UNITED _ "

TECHNOLOGIES

IPTA-007-91

SPE® PROPULSION ELECTROLYZER

for

NASA'S INTEGRATED PROPULSION TEST ARTICLE

w FINAL REPORT

m

November 1988 -- August 1991

Contract No. NAS 9-18030

DRD MA-467T

Data Requirement List Item No. 3

prepared for

NATIONAL AERONAUTICS and SPACE ADMINISTRATION

JOHNSON SPACE CENTER

by

HAMILTON STANDARD DIVISION

SPACE & SEA SYSTEMS DEPARTMENT

ELECTRO-CHEM PROGRAMS

August 1991

® SPE is a Registered Trademark of Hamilton Standard, Division of United Technologies Corporation
b_

_iw

w

UNITED "

TECHNOLOGIES

FINAL REPORT . ItrrA-007-91

SPE® PROPULSION ELECTROLYZER for NASA'S INTEGRATED PROPULSION TESTARTICLE

FINAL REPORT

Contract No. NAS9-18030 • DRD MA-467T, Line Item 3

L_

L .

ABSTRACT

Hamilton Standard has delivered a 3000 PSi•SPE_ Propulsion Electrolyzer Stack and

Special Test Fixture fo the NASA Lyndon B. Johnson Space Center (JSC) Integrated

Propulsion Test Article (IPTA) program in June 1990, per contract NAS9-18030. This

prototype unit demonstrates the feasibility of SPE-high pressure water electrolysis for

future space applications such as Space Station propulsion and Lunar/Mars energy

storage. The SPE-Propulsion Electrolyzer has met or exceeded all IPTA program goals.

It continues to function as the primary hydrogen and oxygen source for the iPTA test

bed at the NASA/JSC Propulsion and Power Division Thermochemical Test Branch.. - -

Recognized potential benefits of an $PE-Electrolysis based Hydrogen-Oxygen (H-O)

propulsion system include a high thruster specific impulse (1_p>400 SEC), high propellant

mass fraction to orbit (>0.8), a safe-to-handle fluid (H20), and the ability to utilize waste

water to produce high performance propellant. The combined effect of these benefits

could produce a significant reduction in the fife cycle cost of large space platforms

such as the NASA Space Station Freedom. While offering these benefits, only limited

testing of an integrated electrolysis based H-O propulsion system had been conducted

prior to the initiation of the NASA/JSC IPTA program. The IPTA ground test bed includes

the water electrolysis system, I-f-0 thrusters, and 3000 PSIgas storage.

The delivered SPE-Propulsion Electrolyzer is a full size Space Station prototype stack,

shown to deliver 3000 PSIA hydrogen and oxygen at any rate from zero (a standby

mode) to the Space Station projected emergency rate of four pounds H-O propellant

per hour. Generation rate may be changed in seconds; start-up from ambient to 3000

PSIArequires less than 20 minutes. More than 850 hours have been demonstrated to date

(August 1991) on the cell stack at full 3000 PSi pressure.

Hamilton Standard has delivered a conceptual flight SPE-Propellant Generator system

design to NASA/JSC in February 199 I, per contract NASg- 18030. The Conceptual System

Design outlined requirements and system configurations for a highly reliable 3000 PSIA

hydrogen-oxygen generator. The study identified critical technologies and

components requiring development. Trade study emphasis was best reliability for a

five-year system life, based on technology to be available by 1995. New concepts

presented include a separate feed wafer supply ORU, a low pressure, low consumption

nitrogen reference system, and a high differential (3000 PSID) pressure cell stack.

Enabling technologies requiring priority development include 3000 PSIA mlcrogravityfunctional gas-water phase separators, high pressure accumulators and a power

supply capable of using excess unused power from the main power bus.

® SPE is a Registered Trademark o( HamiltonStandard, Division of United Technologies Corporation
m

m

w

_ =

w

w

w

w

_ UNITED

TECHNOLOGIES

_&_O_Y@_

5_A_®A_D

FINAL REPORT • IPTA-007-91

KEY WORDS

3000 PSI

Cell Stack

Electrolysis

Electrolyzer

Energy Storage

Hamilton Standard

Hydrogen

Ion-Exchange Membrane

Lunar/Mars

Membrane

NASA

NASA/JSC

Oxygen

Propulsion

Solid Polymer Electrolyte

Space Station

SPE-Propellant Generator

SPE-Propulsion Electrolyzer

SPE-Water Electrolysis

Water

Water Electrolysis

ii
i

m

m

=

i

w

m

J

m

i

_ UNITED

TECHNOLOGIES

FINAL REPORT • IPTA-007-91

T able of Contents page

Abstract .............................................................................................................................. i

1.0 Program Description .................................................................................................. 1

1.1 Phase 1 WBS and Task Descriptions .............................................................. 1

1.2 Major Contract Modifications ........................................................................ 4

1.3 Deliverable Items and Documentation ......................................................... 4

2.0 Prototype SPE-Propulsion Electrolyzer Stack ............................................................. 6

2.1 Cell Stack ........................................................................................................ 6

2,1.1 Cell Stack Design ................................................................................ 7

2.1.2 Stack Fabrication and Assembly ...................................................... 12

2.2 Special Test Fixture ........................................................................................ 15

2.2.1 Basic Test Fixture Design .................................................................... 15

2.2,2 Safety Features .................................................................................. 17

2.2.3 System Control ................................................................................... 18

2.2.4 Data Monitoring and Recording ........................................................ 23

2.2.5 Component Descriptions ................................................................... 23

2.2.6 Fabrication and Assembly ................................................................ 25

2.3 Contractor Verification Test ........................................................................... 34

2.3.1 Test Plan Matrix .................................................................................. 34

2.3.2 Test Set-up ......................................................................................... 35

2.3.3 Test Results ........................................................................................ 35

2.3.4 Delivery to JSC ................................ : ................................................... 43

2.4 IPTA Installation and Operation ...................................................................... 43

2.4.1 Installation .......................................................................................... 40

2.4.2 NASA Operation ................................................................................. 42

3.0 SPE-Propellant Generator Conceptual Design .......................................................... 45

3.1 Trade Studies ................................................................................................. 45

3. 1.1 3000 PSID (One-way) DOMED STACK vs Other Designs ...................... 48

3.1.2 600 PSi GN2 SAVE SYSTEM vs High Pressure Supply ............................ 48

3.1.3 NON-REGENERATIVE vs Regenerative Driers ..................................... 50

3.1.4 "Non- Active" TEMP CONTROL vs 120°F Active Control ..................... 51

3. 1.5 PASSIVE FREEZEPROTECTION vs Active Freeze Control ..................... 52

3.1,6 DOME LOADED REGULATORS vs Electronic Regulators ..................... 53

3.1.7 WATER FEED PUMP Location .............................................................. 54

3.1.8 Combined WATER FEED, TEMPERATURE, DRIER $ Study .................... 54

3. 1.9 Mean Time Between Failure (MTBF) configurations ......................... 56

3.2 Conceptual Design and Layout ..................................................................... 55

3.2.1 System Attributes ............................................................................... 57

3.2.2 System Packaging ............................................................................. 58

3.2.3 Electrical Design .................................................................................

3.2.4 Cell Stack / Phase Separator Module ............................................... 69

3.3 Operating Approach ..................................................................................... 69

3.4 System Development .................................................................................... 72

4.0 Conclusions and Recommendations ....................................................................... 74

Source Document List and Appendixes

iii
E =

t

m

_ UNITED

TECHNOLOGIES

FINAL REPORT • IPTA-007-91

List of Figures page

Figure 1.1

Figure 1.2

Figure 2.1

Figure 2.2

Figure 2.3

Figure 2.4a

Figure 2.4b

Figure 2.5

Figure 2.6a

Figure 2.6b

Figure 2.7

Figure 2.8

Figure 2.9

Figure 2.10

Figure 2.1 la

Figure 2.1 1b

Figure 2.1 lc

Figure 2.1 1d

Figure 2,12

Figure 2.13

Figure 2.14

Figure 2.15

Figure 2.16

Figure 2.17

Figure 2.18

Final Phase 1 Work Breakdown Structure ....................................................... 2

Delivered SPE-Propulsion Electrolyzer and Test Fixture ................................. 3

SPE-Electrolysis Cell Reactions ...................................................................... 7

IPTA 16-Cell Stack and Domes ....................................................................... 8

IPTA 16-Cell Stack Design Summary .............................................................. 12

SPE-Electrolysis Cell Structure ........................................................................ 13

SPE-Electrolysis Cell Components .................................................................. 13

IPTA 16-Cell Stack Assembled ...................................................................... 14

Test Fixture Dimensions .................................................................................. 16

Test Fixture Support Equipment ..................................................................... 16

Simplified Fluid Schematic ............................................................................. 17

Test Fixture Compartments ............................................................................ 18

Mode and State Transitions ........................................................................... 19

Process Control Flow Chaff ............................................................................. 21

Stack and Test Fixture, Front ...........................................................................

Stack and Test Fixture, Right ........................................................................... 27

Stack and Test Fixture, Left ............................................................................. 28

Stack and Test Fixture, Rear ........................................................................... 29

Operator Console .......................................................................................... 30

Electrical Support Console ............................................................................. 31

Control Block Diagram ............................................... :................................... 32

Water Feed Pump Package ......................................................................... 33

Verification Test Matrix .................................................................................. 35

Average Voltage per Cell Performance ....................................................... 37

Stack Efficiencies .......................................................................................... 37

i

iv
z :

=

= ,

i

i

_ UNITED

TECHNOLOGIES

List of

Figure 2.19

Figure 2.20

Figure 2.21

Figure 3.1

Figure 3.2

Figure 3,3

Figure 3.4

Figure 3,5

Figure 3.6

Figure 3,7

Figure 3.8

Figure 3,9a

Figure 3,9b

Figure 3.9c

Figure 3.9d

Figure 3.9e

Figure 3.10

Figure 3.1 1a

Figure 3.1 1b

Figure 3.1 lc

Figure 3.12

Figure 3.13

Figure 3.14

Figure 3.15

Figure 3.16

Figure 3.17

FINAL REPORT • IPTA-007 91

Fi g u r e s (continued) page

Stack Power Requirement ............................................................................. 38

Installation Schematic, NASA/JSC Bldg 356E ................................................ 41

Replacement Liquid Level Sensor ................................................................ 43

Trade Study Criteria ........................................................................................ 45

Interface Definition ......................................................................................... 46

SPE-Propellant Generator Modular Schematic ............................................. 47

Nitrogen Save System ................................................................................... 49

"Non-Active" Thermal Control ...................................................................... 51

Performance of Thermal Coatings ................................................................ 52

MBTF Configurations ...................................................................................... 56

Generator ORU Package ............................................................................... 60

Generator ORU, Front ..................................................................................... 60

Generator ORU, Top ....................................................................................... 61

Generator ORU, Bottom ................................................................................. 61

Generator ORU, Back ..................................................................................... 62

Generator ORU, Left and Right ....................................................................... 62

Regenerable Drier Generator ORU Concept ................................................. 63

Regen. Drier Generator ORU, Front ................................................................ 63

Regen. Drier Generator ORU, Top .................................................................. 64

Regen. Drier Generator ORU, Bottom ............................................................ 64

Feed Water ORU Concept ............................................................................. 65

Generator ORU Electrical System Architecture ............................................. 66

EPC Concept .................................................................................................. 67

Cell Stack / _-Separator Diagram ................................................................ 68

Cell Stack / _-Separator Module ................................................................. 69

SPE-PG Control Mode and State Transitions .................................................. 70

v
UNITED

TECHNOLOGIES

I]:{I&I_I]ILY@_

_AHDA_D

FINAL REPORT - IPTA-007-91

w

w

m

L

m

= 7

m

List of Tables page

TABLE 1-1

TABLE 2-1

TABLE 2-2

TABLE 3-1

TABLE 3-2

TABLE 3-3

DELIVERED ITEMS AND DOCUMENTATION ....................................................... 5

DESIGN ANALYSIS SUMMARY FOR THE CELL STACK ....................................... 11

CELL RESISTANCE DATA .................................................................................. 36

CASE SUMMARY ............................................................................................. 55

BASELINE AND REGENERABLE CONCEPT MASS SUMMARY ............................ 58

ENABLING TECHNOLOGY DEVELOPMENT ITEMS.............................................. 74

Source Document Appendixes

CELL STACK DRAWINGS LIST

TEST FIXTURE PARTS LISTS AND DRAWINGS

TESTFIXTURECOMPONENT DESCRIPTIONS

CELL STACK. TEST FIXTURE TESTDATA

SPE-PG CONCEPT SCHEMATICS, PARTS LISTS

SPE-PG COMPONENT CONCEPT DESCRIPTIONS

vi
m

_ UNITED

TECHNOLOGIES

FINAL REPORT . IPTA-007-91

7

A ckno w le dgeme nt s

Propulsion and Power Division

I IPTA Technical Monitor

Power Branch Chief

IPTA Test Director

Thermochemical Test Branch, Power and Pyro. Head

M. Le

T. Davies

L. Turner

N. Luksa

m

:,._

Space and Sea Systems

Project Engineering L. Moulthrop

E. Shane

R, Petillo

A. Speranza

C. Welch

Business Development J. McEIroy

W. Smith

Analysis S. Bradford

V. Margiott

J. Nason

Electrical Design D. French

Materials P, Qusba

Mechanical Design D. Faye

R. Field

R. Howe

G, Sped

Reliability H. Chan

P. Tremblay

C. Wall

Software Engineering S. Mitchell

Systems Engineering F, Sribnik

Test and Assembly K. Critz

W. Edwards

J. Morse

C. Werther

vii
=

m

w

i

w

_ UNITED

TECHNOLOGIES FINAL REPORT . IPTA-O07-91

1.0 PROGRAM DESCRIPTION

NASA-Johnson Space Center awarded contract NAS 9-18030 on

October 31, 1988 to Hamilton Standard to develop an SPE ® Propellant

Generator, a prototype high pressure water electrolysis system for

propulsion applications. The target application was Space Station

Freedom reboost and attitude control, using hydrogen and oxygen

gaseous propellants generated from excess water. High pressure

water electrolysis has also been identified as an enabling technology

for future Lunar/Mars initiatives. The contract award work was

divided into two consecutive development phases. Phase 1 effort

consisted of development and delivery to NASA-JSC of a full-size

3000 PSIA water electrolysis stack and the preliminary design of a

flight prototype system. The optional Phase 2 consists of final

design, prototype development, delivery and test. This report

relates the activity, results and conclusions of Phase 1.

1.1 Phase 1 WBS and Task Descriptions

The contract statement of work (SOW) for Phase 1 has been

and revised since the initial contract award. The final SOW

(through Amendment 20) for Phase 1 are:

amended

elements

Design, fabricate and test a 3000 PSIA prototype water electrolysis cell stack

sized to produce 99.5% pure propellants at the rates of 0.6 (minimum), 2.0

(nominal) or 4.0 PPH (emergency) with a nominal efficiency better than 70%.

The stack must have a minimum of 15 full-size cells. Preliminary and critical

designs are to be presented to NASA in formal reviews (PDR and CDR).

Fabricate an automated special test fixture for the electrolysis stack and

demonstrate a minimum of 100 hours of 3000 PSIA electrolysis. Provide for

standby, minimum, nominal, emergency and cyclic operating modes.

Conduct a conceptual system design of a flight prototype 3000 PSI hydrogen/

oxygen propellant generator. A flight prototype conceptual design is

necessary to define reference requirements for an SPE-Propellant Generator /

3000 PSI water electrolysis system prior to proceeding with a technology

development program. The results are to be presented to NASA in a formal

System Design Review (SDR).

® SPE is a Registered Trademark of Hamilton Standard, Division of United Technologies Corporation

.
i,,d

_ UNITED

TECHNOLOGIES

FINAL REPORT . IPTA-007-91

These SOW elements were established as separate Work Breakdown

Structure (WBS) elements. Separate WBS elements were also created

for program control and for reliability studies. The final Phase 1

WBS diagram is shown in Figure 1.1.

The Cell Stack task (WBS 100) resulted in delivery to NASA of a

16 cell SPE-Propulsion Electrolyzer prototype stack meeting all SOW

requirements. Preliminary and critical design reviews were

conducted. The cell stack was mounted in the Special Test Fixture,

which was developed under a separate task (WBS 200). The

combined electrolyzer and test fixture demonstrated more than 110

hours of 3000 PSIA operation before shipment and in excess of 740

hours at NASA-JSC. Figure 1.2 shows the SPE-Propulsion Electrolyzer

and special test fixture. { Refer to section 2.0 for further discussion }

The amended Preliminary Design task (WBS 300) resulted in

delivery of a Conceptual System Design focused on high reliability.

A direction for future development was identified. { Refer to section 3.0

for further discussion }

w

I

l Full ,0oScalesPEP Stack )

_110

Full Scale Stack

Design

_120

Full Scale Stack

PDR

--130

Procurement

--140

Full Scale Stack

CDR

_150

Full Scale Stack

Fabric=ion

--160

Slack ,Test

Dale Reduction &

Analysis

I

I PHASE (A88) 1

I

I

200 Special Test Fixture

_210

CorcelX and

Design

220

Procurement

m230

Assembly and

Test

--170

| Package and

Ship

"t--FLDA

Field Support Of

16-cell Slack Test At

NASA

!

I PHASE 2

I

I

System 300 Preliminary Design I

301

to,.,o.oo

System Design Review

I I

Maint. & Salety Management

=410

Reliability Pla_s

& Analyses

--420

Quality Ran

_430

Safely Plan

& Analysis

.--_tO

Program Kickoff

and Setup

--520

Program Management

and Reporls

--530

Financial Control and

Reports

--540

Customer Reviews

Figure 1.1 Final Phase I Work Breakdown Structure

.
: T

w

UNITED

TECHNOLOGIES FINAL REPORT • IPTA-007-91

k..d

96

Figure 1.2 Delivered SPE-Propulsion Electrolyzer and Test Fixture

L

,

ORIGINAL PAGE

COLOR PHOTOGRAPH
_ UNITED

TECHNOLOGIES FINAL REPORT • IPTA--007-91

The amended Reliability task (WBS 400) supported development of a

System Hazard Analysis and Software Requirement Specification for

the Special Test Fixture.

The Program Management task (WBS 500) supported technical and

financial management and control aspects of the effort, including

preparation and submission of all documentation as required by the

contract Data Requirements List (DRL). { re.f section 1.3}

w

_L

w

1.2 Major Contract Modifications

Contract Modification 1 exercised the option to construct a Special

Test Fixture. Coincident with Mod. 1, a Stop Work order was issued

on the Prototype System Preliminary Design task (WBS 300).

Emphasis was directed to the cell stack and special test fixture tasks.

Modifications 15 and 18 directed a down-scope of the original

Preliminary System design task to the present Conceptual System

Design task.

1.3 Deliverable Items and Documentation

Deliverable items and major documentation delivered under this

contract are listed in Table 1-1. Those items required by the DRL are

listed with respective Data Requirement Description (DRD) numbers.

Monthly technical reports were issued on the fifteenth day of each

month from program start until July 1990. Monthly financial

reporting was discontinued in February 1991.

.
=

_ UNITED

TECHNOLOGIES

IH&_I]B,T@_ FINAL REPORT • IPTA-007-9I

TABLE 1-1

DELIVERED ITEMS AND DOCUMENTATION

HARDWARE

I TITLE Cell Stack and Special test Fixture TANNED J,2/90 DATE

TDELIVERY DATE , ]

15/9o ]

DCSEC

DRL T-2183 REQUIRED DOCUMENTS

DRD#

MA-464T

MA-466T

MA-467T

I TITLE

[__Programop.e_r_.a_ting _plan

Monthly Progress Reports

Final Report

PLANNED DATE

December 1988

15 days after

month end

Draft 45 days p_

DELIVERY DATE ....

12/15/88

12/88 through 7/90

2/91 outline---8/91 final

_4_T_ M,_-0307.....

t___

5 OM-084T

,_6Vg_ SE-1186

SE-1198

_1_ _'_' TM-388T

t

Monthly Financial Reports

Operations and

Maintenance Manual

Materials in contact with

02 and H2

Non-Metallic Materials

Materials Usage Report

to final f_E_l a

20 days

month end

50 days before

hardware

With Hardware

January 1989

With Formal Design

Reviews

With Formal Design

12/88 through_91

6/89 draft -- 10/90 final

2/89

2/89

12/22/90

L Reviews

iiM_A.:!2.3.8.L_jFileld..Sei_.@ei•a, lei:)ori................. ASrequjre.qlZiXii_i.i2_.Riigi._iig].9ii_,iii,.iii,i-i=.o

I 17 SE-1150T Preliminary Design Review Feb. 1989 (Stack) 1/23/89

[_ ..........................Pac.k.a_.e ...........................................................................................

I Preliminary Design Review Two weeks after 2/24/89

118

t

1

i

I

_20

12T 

t

L__

.................. Present.a.t.ion ..........................pac .ka.c::je.......................................................................................

Preliminary Design Review Two days after 3/3/89

Minutes _presentation

SE-1151T Critical Design Review May 1989 (Ceil 6/24/89

Packacte............................................ .s!ac_k). ................................

Critical Design Review Two weeks after 7/6/89

Presentation jp_a.,ck.a.g e..........................

Critical Design review Two days after 7/14/89

Minutes p resen_!.a.t!on.................

RA-432TA _Plan December 1988 12/15/88

RA-142TB Acce lance Data Report With hardware 5/10/90

SA-054TD Mishap and Corrective As required

i Action Report

sE-1478T _ign Review 12/90 2/91

System Design Review 12190 2/91

Presentation

NON-DRL REQUIRED DOCUMENTS

TITLE _PLANNED DATE DELIVERY DATE

Safe_ _,December 1988 12/15/88

Hazard Ana!ysis | _--_0T89 final 3/'-8"9"d}'a'_-- 8/89 final

"_--'-fT_ ...................................... _;_ ........ 9;;ii_................................

.
.,...,

w

r...,

_ UNITED

TECHNOLOGIES

FINAL REPORT • IPTA-007-91

2.0 PROTOTYPE SPE-PROPULSION ELECTROLYZER STACK

This section summarizes the configuration and test results of the cell

stack and special test fixture delivered to NASA/JSC for the

Integrated Propulsion Test Article (IPTA) Program. An SPEPropulsion Electrolyzer Stack and Special Test Fixture have been

provided by Hamilton Standard to demonstrate production of

propulsion-grade hydrogen and oxygen by high pressure water

electrolysis.

The cell stack is a full size prototype stack, capable of producing

3000 PSIA hydrogen and oxygen at the Space Station projected

emergency electrolysis rate of four pounds of water per hour. The

S PE-Propulsion Electrolyzer Stack is installed in a special test fixture

designed to provide all control and support required to operate the

cell stack in the IPTA test bed. The stack and test fixture are shown

in Figure 1.2. The SPE-Propulsion Electrolyzer system delivered to

NASA/JSC consists of a 16-cell, 3000 PSI water electrolysis cell stack

and a special test fixture. The special test fixture is comprised of a

fluids system package, a control/monitor cabinet which provides

electrical/electronic support and monitors the process output, a high

pressure water pump package, a process control computer and

operator console, and the electrolysis module power supplies.

2.1 Cell Stack

Water electrolysis dissociates water into hydrogen and oxygen ions

using direct current power applied across an electrolyte. Ions form

gas molecules at the anode (02 generating) and cathode (H2

generating) electrodes. A cell stack is a series of electrochemical

water electrolysis cells where the current passes though all cells in

series.

The IPTA SPE-electrolysis cell differs from a conventional cell in that

it uses no liquid electrolyte. Instead it uses a tough, plastic sheet of

perfluorosulfonic acid polymer approximately 0.010 inch thick,

manufactured by DuPont under the trade name Nafion ® This gives

the cell stack the capabilities to withstand large cross cell

differentials (up to 700 PSID). Product gases and water effluent are

09 Naflon is a trademark of E.I. Dupont de Nemoirs

.
m

_ UNITED

iTECHNOLOGIES

_@_@

free of electrolyte.

reactions.

Hydrogen electrode

(cathode)

Hydrogen

Protonic

Water

FINAL REPORT • IPTA-007-91

Figure 2.1 is a diagram of SPE-electrolysis cell

Solid polymer electrolyte

Oxygen electrode

(anode)

Oxygen

Water, Processheat

L

4H+ + 4e- ... 2H2 2H20 -.* 4H+ + 4e- "{'02

(') (+) Water

4e ii DC Power

Figure 2.1 SPE-Electrolysis Cell Reactions

The SPE-electrolysis cell design that is the basis of the IPTA cell

design has been proven reliable in over 8 million cell hours in

US Navy oxygen generating equipment development hardware and

Royal Navy submarines. Demonstration cells continue to run after

more than 12 years continuous operation.

2,1,1 Cell Stack Design

The 16--cell stack shown in Figure 2.2 has a 9.50" diameter and is

approximately 7.25" thick. The electrolysis cells are compressed and

held between a solid end plate and fluid plate that is cored and

drilled to distribute process water and remove product gases and

excess water. Pneumatic end domes enclosing the stack extend its

operating pressure to 3000 PSIA. The cell stack assembly with domes

weighs 193 LBS and is 13" by 13" diameter. A summary chart of

stack design features is presented in Figure 2.3 (see page 12).

= ,

.
w

_ UNITED

TECHNOLOGIES

FINAL REPORT . IVI'A-007-91

w

i

.t__._...:.___

(226469

Figure 2.2 IPTA 16-Celi Stack and Domes

, ORIGINAL PAGE

COLOR PHOTOGRAPH
_ UNITED

TECHNOLOGIES

FINAL REPORT • IPTA-007-91

m

2.1.1.1 The Individual Cell Components used in each of the 16

cell assemblies are shown in Figures 2.4a and 2.4b. Each cell

assembly includes an O2 and H2 frame, screen package, and separator

plate; a membrane/electrode assembly, a pressure pad, and gaskets.

As seen in Figure 2.4a, the process water enters the cell through the

02 inlet port and is distributed by the oxygen screen package across

the membrane electrode surface Electrolysis takes place at the

anode electrode surface bonded to the membrane and oxygen gas is

formed. The excess process water stream carries oxygen and heat

away to 02 outlet ports on the opposite side of the oxygen

compartment. Hydrogen ions ( H+ ) transport across the solid

polymer electrolyte membrane to react and form hydrogen gas at the

cathode electrode. Water is also transported across the membrane by

ionic association with the H + ions. Hydrogen and water collect in the

hydrogen side screen package and exit through the hydrogen outlet

port.

2.1.1.2 Cell Stack Assembly Individual cell assemblies are

stacked one on top of the other to form a stack. This arrangement is

very compact; each cell assembly is little more that 0.12 inches thick.

As a general description, the cells in the stack are configured in

series electrically and in parallel for fluid transport. Current to drive

the electrolysis reaction is passed in series from one cell to the next

so that each cell is operating at the same current density. The

electrically conductive rubber and metal strip pressure pad assembly

is inserted between each cell assembly to provide even cell

compression in each individual cell active area. This, in consort with

selective platinum plating of current conducting surfaces, minimizes

cell contact resistance. Sheet metal dividers separate cell

compartments from the pressure pad. Screen packages serve several

functions: as mechanical supports to the relatively soft membrane; as

electrical conductors; and as fluid distribution and collection

effectors. As cell assemblies are stacked one on top of the other,

respective hydrogen and oxygen ports punched in the individual cell

components align to form the cell stack H2 and 02 parallel manifolds.

Tetrafluoroethylene (TFE) gaskets and the membrane itself work

with molded ridges in the cell frames to promote gas-tight seals on

manifolds and on the cell periphery.

2.1.1.3 Stack Compression The-cells, fluid plate and end plate

are compressed together by belleville springs acting on twelve tie

rods. The spring washers collectively exert the 34 TONS (approximate)

of force necessary to make the cell gasket seals and load the cell

m

.
m

w

i

7 •

_ UNITED

TECHNOLOGIES FINAL REPORT • IPTA--007-91

pressure pads. The assembly is then encapsulated by two high

pressure domes which are fastened together by twenty-seven high

strength bolts (See Figures 2.2, 2.3 and 2.5). Use of pressure domes

extends the operating pressure range of the cell stack hardware,

normally rated at 300 PSID in standard versions and 1000 PSID with

reinforced frames. The domes are designed for 3150 PSIA nitrogen

pressure during operation and have been proof tested at 4600 PSIG.

The tie rods pass through the fluid plate and as such do not exert any

deflective forces on it. The arrangement of two pressure-equalized

domes opposed about the fluid plate also eliminates pneumatic forces

acting on the plate. These design features allow the weight saving

use of a thin section (1" thick) fluid plate. The arrangement of the

spring stacks opposite the cell stack makes good use of the opposing

dome volume and permits use of smaller profile domes.

2.1.1.4 Fluid and Electrical Connections The fluid plate is

ported from the outside edges to the cell stack face to admit inlet

water and to discharge oxygen/water and hydrogen/water streams.

The fluid plate is also ported in two places to admit nitrogen into the

dome space. The fluid plate accepts flanged line connections to these

ports. The flanges are fastened with bolts and have face O-ring

seals.

The fluid plate functions as the negative terminal to the cell stack,

and is tapped to permit negative power cable bonding. The positive

terminal is a flat niobium plate on the opposite end of the stack.

Flexible current conductors are attached at four locations on the

periphery of the positive terminal plate. These flexible conductors

connect in turn to four insulated copper posts that pass through high

pressure insulated gland seals mounted in the fluid plate. Four

small current feed-throughs were used instead of one large current

feed through to save cost, size and weight. Cell voltage leads from

cells 4, 8 and 12 are conducted through a three-conductor high

pressure gland. Cell voltage instrumentation was minimized by

measuring groups of four cells instead of each individual cell. The

fluid plate is bored to accept two temperature probes.

2.1.1.5 Stack Size Analysis The cell stack was designed to

meet the requirements of the SOW. These requirements are listed in

Table 2-1. The design basis was the 0.23FT 2 electrolysis cell

operating at the requisite 3000PSIA. The number of cells for the

cell stack was optimized based on exceeding the efficiency

requirement of 70%, using best cell performance data. Heat rejection

I0.
m

w

m

_ UNITED

TECHNOLOGIES

FINAL REPORT • IPTA-007-91

was based on an oxygen compartment water flow of

300 CC/CELL.MIN. Diffusion current losses were based on theoretical

and experimental data.

It was determined that a stack of 16 cells operating at a nominal

current density of 812ASF (187 amps) would operate at >77%

electric efficiency. Operation at minimum or maximum currents

would result in modest efficiency losses. The diffusion current

(current to overcome gas cross-diffusion) at pressure and

temperature would be in the range of 12--16 amps. Operating

temperature would be in the range of l10--120°F. System power

penalties were estimated; operation at Standby (no net gas

production) was projected to require a minimum of 305 watts. A

summary of the results is presented in Table 2-1.

TABLE 2-1

DESIGN ANALYSIS SUMMARY FOR THE CELL STACK

SOW DESIGN POINTS " 3000 PSIA operation, STANDBY, 0.6, 2.0, 4.0 PPH electrolysis rates ;

Goal of >70% efficiency.

l_l/_J.l_/k_: NATION ® 120 (10-12 MIL) MEMBRANE, LIQUID WATER ANODE FEED

0.23 FT2 CELL AREA, 300 CC/CELL-MIN

m

TEMPERA TURE (oF)

STACK EFFICIENCY (%)

SYSTEM EFFICIENCY (%)

CURRENT DENSITY (ASF)

CURRENT (AMPS)

STACK VOLTS (16 CELLS)

POWER (WATTS)

0.6 PPH 2.0 PPH 4.0 PPH STANDBY

100 120 120 90

74 77 72

70 75 70

280 812 1550 52

65 187 357 12

26.9 29.9 33.7 25.4

1750 56OO 12030 305

F =

u

w

m

m

2.1.1.6 Cell Stack Materials. The cell design has already

been proven in US Navy 3000 PS IG applications to be fully

compatible with oxygen and hydrogen. The oxygen side is primarily

water (98%) by volume, which allows the use of materials not

normally used for high pressure dry oxygen but perfectly safe for

high pressure oxygenated water. The oxygen side cell materials are

Nafion®, niobium metal, TFE, and a proprietary anode catalyst. The

hydrogen side cell materials are Nafion ®, TFE, zirconium and a

proprietary cathode catalyst. Zirconium was selected in part for

resistance to hydrogen embrittlement.

11.
w

_ UNITED

TECHNOLOGIES FINAL REPORT • IPTA--007-91

The central fluid plate material is passivated 316L stainless steel,

selected for good compatibility with water, excellent hydrogen

embrittlement resistance, good machineability and availability.

Alternate materials (NP35-N) or composites were considered for

future development.

The nitrogen-filled end domes were machined of Inconel 718, a high

strength corrosion resistant alloy common to high pressure vessels.

O-rings used to seal against the fluid plate are Viton.

2.1.1.7 Design Reviews This design passed Preliminary and

Critical Design reviews conducted conducted by NASA/JSC in

February and July of 1989. Copies of the design review

presentations are available under separate cover.

2,1,2 Stack Fabriqation and A_se.ml_ly

The cell stack was fabricated at Hamilton Standard facilities in East

Granby, Connecticut during the fall of 1989. Modified proprietary

operations sheets were used to guide final assembly and check-out.

A list of drawings and components is included in the Source

Document section of this report. Performance verification test results

are related in Section 2.3 of this report

iiI

F :

w

w

IIIll

• SIXTEEN CELLS, 0.23 FT2 ACTIVE AREA

• LIGHTWEIGHT PACKAGING OF PROVEN

OGP CELL HARDWARE

• OPPOSED TORISPHERICAL DOMES

ALLOW THIN SECTION FLUID PLATE

• LIGHTWEIGHT SPRING STACKS

• SPRINGS OPPOSITE CELL STACK FOR

LOWEST PROFILE, WEIGHT

• CELL VOLTAGE MONITORING WITH 4-

CELL GROUPS

• SIZE: 13" LONG BY 13" DIAMETER

• WEIGHT: 193 LBS

Figure 2.3 IPTA 16-Celi Stack Design Summary

w

12.
_ UNITED

TECHNOLOGIES FINAL REPORT • IPTA_)07-91

Manifold/screen _-- 02 side

H2/H20 gasket /

"out / 7 /_O 2 seParator

gasket - f' J. O2screen H2Oin

__ .

L E_ '_-__- _'-_ --_-o2 frame

SPE membrane and-_ --

electrodes (M&_

/ H2/H20

H 2 gasket J out"-

H2 sideAir breather screen-

.......... _,_._ _ H 2 frame

___ 1___ ,::____._ . z____." _ L Capped port

-- H_2separator

-- H 2 screen

--ZR fret plate

Air side- -Woven NB strips

I

NB fret plate- _Pressure 'pad

Figure 2.4a SPE-Electrolysis Cell Structure

m

m

= ]

i==,-

Figure 2.4b SPE-Electrolysis Cell Components

w

13. ORIGINAL PAGE

COLOR _:_HOTOqRAPH
7

m

_ UNITED

TECHNOLOGIES FINAL REPORT . _TA_07-91

-"- Z

i

i

_D

L

m

= = : C26688

Figure 2.5 IPTA 16-Celi Stack Assembled

ORIGINAL PAGE

BLACK AI',_D WHITE Pr_OTOGRAPR 14.
w

i

_ UNITED

TECHNOLOGIES FINAL REPORT • IPTA--007-91

2.2 Special Test Fixture

The SPE-Propulsion Electrolyzer Stack is installed in a special test

fixture designed to provide all control and support required to

operate the cell stack in the IPTA test bed. Diagrams of the stack

and test fixture components are shown in Figures 2.6a and b. The

special test fixture is comprised of a fluids system package, a

control/monitor cabinet which provides electrical/electronic support

and monitors the process output, a high pressure water pump

package, a process control computer and operator console, and the

electrolysis module power supplies. The test fixture is designed for

one-gravity ground test conditions only.

Electronic control allows the operator to control and monitor selected

parametric functions in the gas generating process from a remote

location in a manual or fully automatic mode. The test fixture control

program has built-in alarms and thirty-nine automatic shutdowns.

From the control console, the operator can change power to the cell

stack and alter the gas production rate in either a steady or a cyclic

mode.

2.2,1 Basi_ Test Fixture Design

A simplified version of the test fixture fluid schematic is given in

Figure 2.7, showing major fluid components and streams.

The test fixture fluid section provides the means to circulate water,

separate gas/water mixtures, recover water, discharge heat, control

water level and control pressures. The system fluid schematic

SVSKll6070 is provided in the Source Document section. The

following is a brief discussion of the test fixture fluid section.

Process water is circulated on the oxygen side by the circ pump. It is

introduced into the cell stack [ ,4 ] at a rate approximately 200 times

the electrolysis rate. Oxygen and water exit the stack [ B ] and enter

the O2/H20 phase separator. Water exiting the oxygen separator [ F]

gives up heat removed from the cell stack to a heat exchanger.

Oxygen gas [ D ] exiting the separator is back pressured to 3100 PSIA

by a regulator referenced to nitrogen [ L ]at 3141 PSIA. Oxygen

relieved through the regulator is available for storage or use down

stream of the regulator.

15.
_ UNWED

TECHNOLOGIES

_&_T@_ FINAL REPORT • IPTA--007-91

I..................................... li_"i_'6i';_'i:'7_'i"'i_i-_Ti;i'i_l"'_;iCi'6-i_'l'i"i;;'"_'_'_'l_ ........................................

I

l ENVELOPE

FRONT , • INTERFACE

SIDE "_[_ ,_ SIDE

.. 1!.

E

-_ 20" ,,------.4P_- ....i FLUIO _4TIERFACE il.,..

Figure 2.6a. Test Fixture Dimensions

..i

t.,=J

=

SPECIAL TEST FIXTURE

SUPPORT EQUIPMENT

COMMERCIAL PUMP

DEIONIZER, FILTER

fl-cm MONITOR

I I

HP VECTRA 308 CPU AND

MONITOR ELECTRICAL SUPPORT PACKAGE

WIDE FORM PRINTER HP-3497 DATA ACQUISION AND CONTROL

CELL STACK

POWER

40" I SUPPLIES

c,_ls _ (NASA GFE)

to!_rom ]

Sp_a# [

Test _

VALVE AND PUMP POWER

IEEE 488 DATA LINK

IEEE DATA LINK

l_[]l=:=i_iii::i::iiii!ii!ii!ii!!!_:i:_:.i!i_iii!i!_:ii_;ii; ..... _] _

320" coax ctde (IEEE-488)

320" #our.wie (RS-2"J2)

7iiilii7i7{71iii{i{2!7i!_!!:i!i

Jiiili_TJiii!!i!ii_iiTi77!iiiiTiTii;

=

Figure 2.6b Test Fixture Support Equipment

16.
!

L .

r

_ UNITED

TECHNOLOGIES FINAL REPORT . IPTA-007-91

,','$EPN::_TOR

J

1-120

/1

H20 _ K

L

C B

_pA_'rl_

F

-- ,..._ -----------_,oe, e,_,,_ ............. , .......... zzzzzzzrzz ....... -_ .......... :

A 3115 PSI CIRC H 20 IN E 3000 PSI HYDROGEN OUT J DE-GAS / PURGE VENT

B OXYGEN/CIRCH20OUT F 3100PSlRECIRCH20 K 25 PSI FEED H 20

C H2/CATHODE H20OUT G H20W/DISSOLVEDH2 L 3141PSI REFERENCE /

D 3100 PSI OXYGENOUT H RECOVERED H 20 DOME NITROGEN

Figure 2.7 Simplified Fluid Schematic

Hydrogen and water exit the cell stack [ C ] and enter the high

pressure H2/H20 phase separator. Hydrogen gas [ E ] exiting the

separator is back pressured to 3000 PSIA by a regulator referenced

to nitrogen [ L ] at 3141 PSIA. Hydrogen relieved through the

regulator is available for storage or use down stream of the

regulator. Water removed from the hydrogen [ G ] is recovered and

stripped of any dissolved gas [ j ] prior to recycling the water [ H1

back to the feed pump inlet. Level sensors and process conditions

determine the rate that new feed [ K ] and recovered water is

injected into the process water circulation loop to maintain a water

balance.

,,,..--

m

i

m

2.2 2 Safety Features

System safety is based on pressure hierarchy of nitrogen being

higher than oxygen, which in turn is higher than that of hydrogen.

This hierarchy is maintained during operation through a system of

cross-referenced gas pressure regulators. N2 inlet and relief

regulators are referenced to O2 so that any increase or decrease in

O2 is followed by a corresponding change in N2 pressure. H2 and 02

back pressure regulators are both referenced to N2 so that they will

follow N2 pressure trends. In this way, during the initial

pressurization, normal operation and during the rapid

17.
_ UNITED

TECHNOLOGIES

MA_t]ILfi7@I]8 FINAL REPORT • IPTA--007-91

depressurization of a shut down, the regulators will maintain the

pressure hierarchy of N2>O2>H2. In-line precision flow restrictor

orifices keep the fluid flow in check to predetermined safe levels.

Redundant relief valves are installed in designated fluid lines to

ensure controlled pressure venting in the event of overpressure

conditions. In the event of H2 loss, N2 will back-fill the H2 side to

preserve 02 to H2 differential pressure to within mechanical limits of

the cell.

The cell stack is encapsulated in a vessel pressurized with nitrogen.

In the event of external cell stack leakage, inert nitrogen will leak

inboard by virtue of the N2>O2>H2 pressure profile.

SPECIAL TEST FIXTURE

LAYOUT, TOP VIEW

_I_RFACE

Q. E_'T ,_aOE}

BACK

o_ _ _

• VERTICAL PARTITIOn,IS SEPARATE THE O _' AND H= COMPARTMENTS

• BASE IS AN OPEN GRATE; SIDES AND TOP ARE OPEN

Figure 2.8

Test Fixture Compartments

On the test fixture, oxygen and

hydrogen components are

segregated by vertical partitions.

A top view diagram is given in

Figure 2.8. With the exception of

low power instrumentation,

electrical operation is confined to

the nitrogen management

section. The test fixture open

structure allows for any gas

leakage to be diluted and

dissipated in a vented test

facility. H 2 sensors located above

the test fixture will initiate a

system shut down should the

hydrogen exceed a safe level.

Internal unsafe levels of hydrogen-in-oxygen and oxygen-inhydrogen are monitored with sensors in the gas vent lines. A

guarded switch on the electrical console can be used for emergency

shut down, shutting off all AC power and initiating a pneumatic

controlled system depressurization and shut down.

2,2.3 System Control

The special test fixture provides for automatic operation and control

of the production of product oxygen and hydrogen at the minimum,

nominal and maximum rates of 0.6, 2 and 4 PPH. Manual control of

devices can be achieved for pre-operational checkouts• Other

controls include process and system pressure loading, process water

w

i ,

18.
7_

U

__m

w

w

=_

L.J

H

w

_ UNITED

TECHNOLOGIES

FINAL REPORT • IPTA-007-91

circulating pump speed,

components heat tracing.

cooling water regulation and fluid

2.2.3.1 Software Control The software control consists of

four modes and seven states. A State Transition diagram shown in

Figure 2.9 illustrates the possible mode and state transitions. The

four modes are OFF, PREPARE, ON and MANUAL. The seven possible

states are Off, Fail, Fill, Purge, Pressurize, Process-Vent and Process.

The OFF mode can be reached from any mode and state. In the OFF

mode, the system is depressurized to ambient conditions. The

PREPARE mode can only be entered from the OFF mode and the Off

state. During PREPARE, the H2 phase separators are filled to the

correct water level and the H2 volume is purged with N2. ON follows

PREPARE and can only be entered from the Purge state. Electrolysis

occurs only in the ON mode. MANUAL mode is used to check system

communications or hardware operation. Like PREPARE, this mode

can only be reached through the OFF mode and the Off state.

@OOE TP_N$_TUONS

w

W

STATES

A) MANUAL OFF

FAIL

B] OFF OFF

FAIL

C) PREPARE RLL

PURGE

FAIL

D) ON PRESSURIZE

PROC-VNT

PROCESS

FAIL

NOTE - If system fails, the syslem can only be restarted by recycling power. The mode is reset to OFF

Figure 2.9 Mode and State Transitions

19.
w

.-__.

m

w

w

M

w

w

w

_ UNITED

TECHNOLOGIES

FINAL REPORT • IPTA--007-91

The subsystem is in the Off state at the beginning and end of

operation. In this state, all valves are in their unpowered positions

unless the depressurization from Process has not occurred normally

and a powered shutdown was necessary. If a powered shutdown

was engaged, the valves are configured to their unpowered positions

once ambient pressure has been reached.

A failure can occur in any state whereupon the state changes to the

Fail state. Failures are signaled by satisfying anomaly conditions.

To restart the system from Fail state, system power must be cycled

(or the software reinitialized). The system is automatically reset to

the Off state in the OFF mode.

2.2.3.2 Operating ModeState sequences. Figure 2.10 presents

the process control flow chart. To begin operation, the PREPARE

mode is entered and the first state reached is Fill. Here, the operator

is prompted to manually fill the H2 phase separators through fill

ports. When the levels are between 1100 and 1110 on each

separator and the operator is satisfied, the subsystem progresses to

the Purge state. (The level sensor configuration 1100 means that the

first and second level sensors are on and the third and fourth are

not--indicating that the water level is somewhere in between Sensor

2 and 3.) In the Purge state, the 02 phase separator is filled to 1100

using the feed pump. When the 02 phase separator has been filled,

the N2 pressure is raised to 50 PSIA. When the N2 pressure reaches

50 PSIA, the N2-H2solenoid valve is opened and the H2 volume is

purged with N2.

When the N2 pressure has fallen to ambient pressure from 50 PSIA,

the operator may initiate transition to the ON mode. The initial state

in ON mode is the Pressurize state. The N2 pressure is raised to 200

PSIA and then the N2-H2 solenoid valve is opened briefly to bring the

N2-H2 pressure differential within operating pressure bands. Then

the system transitions to the Process-Vent state where current is

applied to the cell stack to begin electrolysis gas generation. In this

state, the current is ramped up to the nominal production rate and

gas is vented for two minutes at approximately 200 PSIA. The two

minute VENTTIME is of sufficient time to allow the subsystem to

produce gases with 99.5% purity. Then, the N2 inlet valve is opened

and the system is allowed to increase in pressure until the N2 volume

can be maintained at approximately 3141 PSIA. At this pressure, the

20.
_ UNITED

TECHNOLOGIES

FINAL REPORT . IPTA-007-91

oxygen generated will be at 3100 PSIA and the hydrogen will be at

3000 PSIA.

The state transitions to Process state when pressure exceeds

3000 PSIA. In Process, the gases are no longer vented. Instead, they

are directed to storage tanks.

T

Static modification

Set data logging interval

PREPARE mode

U

Ii!

L_

W

i

= =

Check Hz/H20 separator level

Check O_¢H20 separator level

I N2 purge H2/H_C)subsystem I

T

i N2 pressurize to 20O PSI

T

i Electrolysis min for at 99.5%200 PSi gas for purityfour I

I pressurization Begin electrolysis to3000 PSl I

I 3100PSIO 3000PSIH /

2; 2

I STEADY operation _ CYCLIC option

",,, -

Figure 2.10 Process Control Flow Chart

21.
u

m

_ UNITED

TECHNOLOGIES

[X]_£I_I][L_@I_ FINAL REPORT • IPTA-007-91

The system operator has two different choices in Process state;

Cyclic or Steady (default). Steady operation is simply continuous

operation at a fixed generation rate. The operator may select one of

three gas generation rates : maximum, nominal (default), and

minimum generation rates (4.0, 2.0, and 0.6 pounds H20 electrolyzed

per hour respectively). The generation rate is selected by toggling a

software defined key (soft-key) labeled GENRATE. The operating

current can be incremented or decremented from the selected

GENRATE value by +1 amp increments using the +AMPS and-AMPS

soft-keys.

During Cyclic operation, the system operates at a fixed generation

rate for 54 minutes and then operates at standby conditions for 36

minutes. A low standby cell stack current (theoretically equivalent

to the cross-cell gas diffusion rate) is estimated from system

temperature and pressure. The standby current is then controlled to

maintain operating pressure in the system. This type of operation is

designed to simulate a Space Station low earth orbit dark side/light

side power cycle.

2.2.3.3 Additional software controls. In addition to the features

described beforehand, the system software has five defined controls.

The first control (Control 1) is for the 02 phase separator, feed pump,

and N2 purge. Basically, this control specifies the sequence of events

in the Purge state and regulates the feed pump in Process-Vent and

Process to maintain the water level in the O2 phase separator.

Control 2 maintains the water levels in the high and low pressure H2

phase separators. Timers are included in these controls to insure

proper drainage or filling. If these timers exceed calculated values,

then a failure occurs.

Control 3 operates the N2 valves in the Pressurized and Process-Vent

states to bring the H2 pressure within control bands and to raise

system pressure. Control 4 is designed to lessen the impact of valve

failure (either open or closed) during depressurization. The system

should detect abnormal depressurization and respond by closing the

appropriate solenoid valve. This action should minimize the

increasing pressure differentials caused by the failure. The last

control, Control 5, defines the operation of the power supply. This

operation is dependant on the configuration options previously

described.

m

u

22.
_ UNITED

TECHNOLOGIES

FINAL REPORT - IPTA-007-91

2.2.3.3 Other Controls. Process and system pressure loading,

process water circulating pump speed, cooling water regulation and

fluid components heat tracing are other controls that are not

managed by the main controller. The system of cross referenced gas

regulators, vent valves and flow restrictors controls pressurization

and depressurization without power. Circ pump speed is manually

set by changing supply voltage to the circ pump motor. Cooling

water regulation is controlled by a freon-actuated coolant regulator

valve set to operate in the range of 100--120°F. Electric heaters on

oxygen regulators and other components are managed by individual

heater controllers mounted in the base of the test fixture fluid

section.

=

u

w

t

2,2,4 Data Monitoring and Re¢0rding

Remote monitoring of the control functions allows the operator to

view operation progress in the hydrogen/oxygen manufacture and

anticipate trends in flow, pressure, water level and electrical power

outputs. Twenty-one data points are printed out from a selected

interval of one to nine minutes and with any automatic shut down.

Data is also displayed on the process monitor and can be recorded on

the controller's 160 meg hard disk drive at the maximum frequency

of one update per control cycle (approximately 2 seconds). These

data points printed out are as follows:

Dale : D/M/Y

Time : H/M/S

Mode :Man/Off/Prep/On

Slate: Off/Fill/Fall/Purge/Press/Proc-Vnt/Proc

Cycle : On/Off

Press H2 : (2) - PSIA

Press02 :(2) -PSIA

Press N2 : (2) - PSIA

Press H2 : - PSIA

Press H2 : - PSIA

CellVollage -groups (4)

CellCurrent-AMPS

Temp HaO In(module) -dog F

Temp H20/O 2 out (module) -deg F

Temp CellSlack -deg F

Row, Cell Slack - CC/MtN.

Resistivity, Water - M-fi

Rate water consumed - CC/M_N.

Temp Heat Ex In/out - deg F

0 2 Separator - Level

H2 Separator - Level

H2 Separalor - Level

2.2...5 (_omp0nen_ Descriptions

The system as supplied to NASA-JSC is comprised of a 16-cell,

3000 PSI water electrolysis cell stack, a fluids system package, a

control/monitor cabinet, a high pressure water pump package, a

process control computer and operator console, and the electrolysis

module power supplies. Descriptions of each of the test fixture major

components follow in this section. Details of major fluid components,

schematics and component lists are provided in the Source Document

section.

23.
m

m

_ UNITED

TECHNOLOGIES

HA_DB_@H FINAL REPORT • IPTA-007-91

2.2.5.1 Special Test Fixture Fluid Package The test fixture

package (shown in Figures 2.11 a, b, c, and d) provides the fluid

processing components and lines which are required to activate and

control the cell stack in a controlled and safe manner. It also serves

as a support stand for the domed cell stack assembly. The open

structure of the test fixture allows for ventilation, dilution and

dissipation of product gases in the event of leakage. The test fixture

is partitioned with vertical panels that separate the hydrogen,

oxygen, nitrogen/water/electrical components in a compact grouping

designed to minimize line length and gas volume. Instrumentation

such as level sensors, gas analyzers, temperature, flow and pressure

transducers are included in the fluid loops. Gas/water separators

allow the gases to be collected and return the process water to the

recirculating loop through pumps. Regulators maintain the product

gases in the pressure hierarchy of nitrogen over oxygen over

hydrogen. Orifices in the fluid lines control the flow during

shutdown. Finally, line filters are installed prior to critical flow

control components to insure functionality.

Metals wetted with oxygen or oxygenated water are primarily

Inconel, whereas metals wetted with hydrogen, hydrogen saturated

water or nitrogen are 316 stainless steel. TFE or Viton were the

elastomers used throughout.

2.2.5.2 Operator Console The operation of the system is

controlled at the Operator Console, Figure 2.12, where all data are

received and control commands are issued to the cell stack support

components. The Console includes a Hewlett-Packard HP 308C

computer with an HP basic control extender card, an EGA monitor for

visual display and a printer to record key data from twenty two

channels. The monitor also displays a map of keyboard function

keys for the different programmed modes of operation.

2.2.5.3 Electrical Support Console Processed operational data

at the Operator Console is received from the Electrical Support

Console, Figure 2.13, through a 320-foot coax cable. The console

includes a Hewlett-Packard Data Acquisition Control Unit (DACU) HP

3497A which receives instrumentation data from the Special Test

Fixture and operates process components. These include hydrogen

monitors, cell stack operation elapse timer, power supplies for the

circulation pump, level sensors, pressure and flow transducers, and

24.
w

k...

_ UNITED

TECHNOLOGIES

I_1_!]1_'_@1_ FINAL REPORT • IPTA-007-91

valve actuators. The control block diagram in Figure 2.14 shows the

input/output of the HP 3497A DACU.

2.2.5.4 Cell Stack Power Supplies Two Sorensen DCR 40-250

Power Supplies provide the electrical power to the cell stack. The

power supplies are connected in parallel and are remote controlled

from the HP 3497A DACU through a current loop. This remote

control allows for output current level variations to the cell stack

including programmed cycling and ramping. The current level is

measured across a shunt (SH102) mounted in back of the power

supplies along with the power contactor (K103).

2.2.5.5 Water Pump Package A commercial high pressure

water pump and water conditioning equipment are packaged

together (Figure 2.15). Electrolysis make-up water and degassed

hydrogen-side water are injected into the 3100 PSI oxygen side

process water loop using a high pressure piston pump (FP500). At

the low pressure inlet, the water flows through a resin bed deionizer

(DI506) and a replaceable cartridge filter (F501). A resistivity

monitor (RS505) checks the incoming process water. On initial

system start, feed water is diverted to drain until a minimum

resistivity of 1 Mr2 is achieved. During operation, a detected water

quality of less than 1 M O will initiate a warning, followed by a shut

down of the system. The pump outlet has a pulse damper plumbed

installed to remove 90% of the pressure pulses from the pump outlet

stream, making pressure control of the system much more even at

full operating pressure. A relief valve (RV510) on the high pressure

pump outlet relieves at pressures exceeding 3200 PSIG.

Materials in contact with the water include ceramic (piston, ball

checks), TFE (supply plumbing, piston seals) and 316 stainless steel

(pressure plumbing, pump and check valve housings).

2.2_6 F_brioatign and Assembly

The test fixture was fabricated and programmed at Hamilton

Standard facilities in East Granby, Connecticut during 1989, with final

modifications during 1990. A Software Requirement Specification

(SRS) was kept up to date to control system software configuration.

The test fixture was pressure checked at 3500 PSIG, the limit of the

actuated valves. A list of drawings and components and other

applicable documentation is included in the Source Document section

of this report. Performance verification test results are related in

Section 2.3 of this report.

25.
_ UNITED

TECHNOLOGIES

I_I_I]IL'_@I_ FINAL REPORT . IPTA-007-91

r

m

k...

L_

Figure 2.11a Stack and Test Fixture, Front

26.

COLOR PHOTOGF(:APH
UNITED

TECHNOLOGIES

FINAL REPORT • IPTA-007-91

-_,_.

m

i

=

i

II

i

Figure 2.11b

COLOR PHOTOGR/_Pi-t

Stack and Test Fixture, Right

27.
UNITED

TECHNOLOGIES

FINAL REPORT • IPTA-007-91

z

r -

=

w

C27398

B

[]

=

[_ _ ¢_ _i -, :- _ :-_

Figure 2.1 lc Stack and Test Fixture, Left

28.
_ UNITED

TECHNOLOGIES

FINAL REPORT . IPTA-007-91

l

m

i

m

Figure 2.11d Stack and Test Fixture, Rear

COLOR :........ r ..... !

29.
w

_ UNITED

TECHNOLOGIES

FINAL REPORT • IPTA-007-91

L ;

w

=

v

!

@

i

i

m

!

!

r_

w

Figure 2.12 Operator Console

30,

ORIGINAL r__,_,..-

COLOR PHOTOGRAPH
UNITED

TECHNOLOGIES

FINAL REPORT • IPTA-007-91

w

m

C27395

C r,, 4, [,,,£ PAGE

COLOR PHOTOGRAPH

Figure 2.13 Electrical Support Console

31.
_ uNrrED

TECHNOLOGIES

FINAL REPORT . IPTA-007-9I

w

IHP 308C

CONTROLLER

OMPUTER

MS_DOS

GPIB" _ COAX. r----------1 GPIB"

...... _- IEXTE NOER}4,-_ -- _1E XTENOER I,_.,,_%.o,,,.,,,_=

L.__._,_J 3Z0FT. L__._._J _

AOOR

1 PT404

2 PT207. I

3 PT207-2

4 PT307-1

5 PT307-2

HP 3497 DATA ACQUISITION

UNIT SERIAL

320 FT. 'SLOT #0 SLOT #1 SLOT 12 SLOT #3

ANALOG IN ANALO0 OUT D)GITAL OUT DIGITAL JH

(option 20) (opllon 1301 (option 1 I0) {option 050)

• GE't_EnAt

PunP,'_SE

IHTEnFACE

BUS

G/L4_

0 FP500 Flow

1 PWR101

CHAN.

0 RS505

1 CELLS 1-4

2 CELLS 5-8

3 CELLS 9-12

4 CELLS 13-16

5 FT205

6 SH102

7 TI06

8 TI05

9 PT308

tO GA3t7-'t

11 T223

12 T224

13 FT511

14 T107-1

15 T1072

16 GA317-2

17

18

19 TC REFERENCE

EbLA/t CHAN

0 SV403 0 LS201-1

1 AOV415.AOV508 1 LS201.4

2 SV507 2 LS301-1

3 SV502, FP500 3 LS301-4

4 GP204 4 LS322.1

5 K103 5 LS322-4

6 AOV304 6 GAt04 (1,2)

7 AOV215 7 GA217

8 AOV216 8

g SV409 9 LS20t.2

IO AOV213 _0 LS201-3

I1 AOV313 11 LS301-2

12 AOV302 . 12 LS301-3

13 AOV327 13 LS322-2

t4 AOV418 14 LS322-3

15 (ALAI_IM) 15 Facilily

Inledock

,i

SLOT#4

V 'T,%Loo,.

IE, V • HAMILTON

STANDARD

® urc _lamdlonSl4_d,lfcl

IPTA SPE®-PE SPECIAL TEST FIXTURE

CONTROL BLOCK DIAGRAM

SVSK116069

pno3 ENG:I.CMQ_hI_ LASTnEv _s 199n

L

Figure 2.14 Control Block Diagram

32.
UNITED

TECHNOLOGIES

FINAL REPORT • IPTA-007-91

\

m

Figure 2.15

_-_L__._,. p,etGE'

COLOR PHOTOGRAPH

Water Feed Pump Package

33.
r .

u

w

w

L___=

it,,,,,/

w

LJ

[]

w

m

r_

w

_ UNITED

TECHNOLOGIES

FINAL REPORT • IPTA-O07-91

2.3 Contractor Verification Test

The contract SOW required a performance verification of the SPEPropulsion Electrolyzer prototype cell stack and test fixture, to be

conducted by Hamilton Standard prior to shipment to NASA/JSC. The

performance requirements to be met at 3000 PSIA during testing

were:

• Operation for a minimum of 100 hours at >3000 PSlA

• Operate at 0.6, 2.0 and 4.0 PPH gas generation rates

• Operate in a Standby mode with no net gas production

• Operate in a 54 min. Generate / 36 min. Standby cyclic mode

• Operate at greater than 70% efficiency at nominal rate

• Produce 99.9% pure hydrogen and oxygen

Verification of all operating modes of the Special Test Fixture,

including start-up, normal and emergency shut downs was also

required.

All of these performance verification requirements were met by

April 1990 and documented in a verification test report issued to

NASA/JSC (IPTA-018-90, June 1990).

2.3.1 Test Plan Matrix

The test plan matrix for the SPE-Propulsion Electrolyzer (SPE-PE)

verification tests conducted at Hamilton Standard is shown in Figure

2.16. All but initial stack leakage and short (Health) checks and the

low pressure initial operation (Green Run) were conducted using the

Special Test Fixture.

Following assembly of the cell stack, cell stack Health checks were

conducted. The Green Run was performed to condition the cell

stack and to obtain parametric performance data on all 16 cells.

Witness filters were used to document final stack cleanliness.

As a final check-out of the operating system, the Special Test Fixture

was operated using a substitute 6-cell stack. Low pressure check-out

tests (LoP Check Out) with'the 16-cell stack installed in the Special

Test Fixture confirmed good system operation in all modes prior to

operating the cell stack at high pressure. Pressure domes were then

installed on the cell stack. High Pressure operation (HiP Check Out)to

3100 PSIA oxygen, 3000 PSIA hydrogen followed to demonstrate basic

high pressure functionality of the combined system. An extended

100 Hour Run followed at high pressure, at the nominal (2 pplt),

34.
_ UNITED

TECHNOLOGIES

_,_1_1]_'i_@1_ FINAL REPORT - IPTA--007-91

(2 PPH), minimum (0.6 PPH) and maximum (4.0 PPH) electrolysis

rates. During this run, the product gas rates was measured and

sampled. Testing concluded with a demonstration of Cyclic

operation and parametric testing.

w

Health

Green Run

Test Fix. (6-cell)

LoP Check Out

HiP Check Out

100 Hour Run

GENERATION RATE

O

Min,Nom,Max

X

X

X

X

@ •

Standby Cyclic

X X

X X

X X

SYSTEM PRESSURE

200 PSIA

X

X

X

3100 PSIA

X

X

O Min., Nom, Max rates: 0.6 PPH H20, 2.0 PPH H20, 4.0 PPH H20

O Standby : maintain system pressures with no net gas output

_} Cyclic : 54 min. of Nora. gas generation followed by 36 min at Standby

O Health checks include cell resistance and cross cell diffusion tests

[I

O

Healtt

X

X

X

X

Figure 2.16 Verification Test Matrix

w

w

m

For all high pressure, integrated (cell stack and test fixture) testing,

test logs were maintained as written operator notes and as automatic

data record sheets printed periodically by the test fixture system

controller.

2,_,2 Test Set-up

Testing was conducted on the cell stack and test fixture during the

period of November 1989 through May 1990 at Hamilton Standard

Space and Sea department, Electro-Chem program facilities in East

Granby, CT. All cell stack and special test fixture tests were

conducted in a steel-walled test chamber (12' x 12'x 10'14) equipped

with high volume air exhaust, hydrogen detection, external venting

of product gases, high purity water supply, high pressure nitrogen

supply, electrical power and provision for remote control.

m

u

35.
= =

m

w

w

w

w

_ UNITED

TECHNOLOGIES FINAL REPORT • IPTA-007-91

2,3.3 Test Results

The test matrix was completed by April 1990. The cell stack

performance met all SOW criteria as stated above, eventually

completing 110 hours of 3100 PSIA operation at Hamilton Standard.

The Special Test Fixture performance was good with the exception of

the high pressure separator level sensors. This problem was

resolved during the NASA/JSC test phase.

2.3.3.1 Cell Stack Performance. All data taken from the

original green run through to the completion of the test matrix shows

cell stack performance as typical of previous high pressure cell

stacks. Efficiency criteria are met for nominal operating currents.

TABLE 2-2

Resistance values

Post test As built

12/22/89 12/1 6/89

cell # m_ m,Q

1 3.1 ...... 2.9 ..........

............ 2 ............. -............ 315 ............ ' 2.8

.........._3................... 2_.=6...... 2.7

,. , 4 .......2.8 .............. 2:4 ..........

.......5 ................ .2....7_................... 2.-.7. ..........

6 2.7 2.6

.......... 7 ........... _..........3..2.......................... .2...§_.......

8 2.6 2.5

.._....

9 3.0 2.6

1 0 2.8 2.5

........................... _.................................. _ .............................

11 3.4

12 2.6

13 2.5

__..L4 ..........2-5............

15 2.6

16 2.5

2.6

2.5

2.5

.......... 2:.6=.....

2.6

2.6

F_.cells................. 4S:i...... ..... &!..7........

.............. 2__8. ............................ .2,.6........

Post test As built

The cell resistance data indicates

typical cell resistances for cells of

this type. Low cell resistance in

the range of 0.6 mf_/FT 2, or 2.5 mf_

per cell is desirable. The cell stack

experienced a slight growth in

cell resistance from when it was

first assembled to completion of

the low pressure Green Run.

Resistance values remained

constant through the remaining

high pressure tests. A test

anomaly and shut down, loss of

water circulation, experienced

during the first hours of the

Green Run is suspected to have

caused the resistance growth.

Operation without proper water

recirculation, even for a few

minutes, will result in some water

loss from the cell membranes.

Performance loss is estimated to

be -0.040 mV per cell. As-built

and post test cell resistances are

listed in Table 2-2.

Figures 2.17, 2.18 and 2.19 present performance data at 3100 PSIA

oxygen pressure, 3000 PSIA hydrogen pressure and temperatures

averaging l15°F (+15°). Data is taken over the minimum to

emergency gas generation range, or 273 to 1500 AS F.

36.
m

_ UNITED

TECHNOLOGIES FINAL REPORT • 1PTA-007 91

3100 PSIA POLARIZATION (26 APR 90)

Avg. Cell

mV

2500

2400

2300

2200

2100

2000

1900

1800

200 400 600 800 1000 1200 1400

I

1600

Current Density, ASF

Figure 2.17 Average Voltage per Cell Performance

i z_==.

-= L..-

Eff

100%

95%

90%

85%

80%

75%

70%

65%

60%

2O0

Cell Stack Efficiency (26 APR 90)

400 600

Figure 2.18

800 1000 1200 1400 1600

AMPS/FT2

Stack Efficiencies

4- Eff

-'_ Veff

I eff

37.
-_.._

u

_ UNITED

TECHNOLOGIES FINAL REPORT . IPTA-007-91

CELL STACK POWER REQUIREMENT (26 APR 90)

14.0

12.0

10.0

8.0

KW

6.0

4.0

2.0

0.0 I I i I I I

200 400 600 800 1000 1200 1400

AMPS/FT2

Figure 2.19 Stack Power Requirement

I

1600

L

Voltage is averaged over the four group readings of four cells each to

produce Figure 2.17. The polarization curve is fairly linear through

to 1300 ASF, the established operating range of the US Navy oxygen

generator cell stacks. Average cell voltage at minimum (273 ASF)

generation rate is 1.82 volts; average cell voltage at nominal (817

ASF) generation rate is 2.10 volts. The maximum voltage reached at

the emergency current density of 1500 ASF is 2.46 volts per cell.

These points agree with typical data for previous new US Navy cell

stacks.

Cell stack efficiency, the product of current and voltage efficiency, is

shown in Figure 2.18. The cell stack is shown to exceed the SOW

requirement of 70% at the minimum and nominal gas generation

rates. Stack efficiency reduces to 62% at the emergency rate of 1500

ASF, The dominant driver in overall efficiency is voltage efficiency,

which ranges from a high of 88% at 273 ASF to a low of 66% at the

emergency 1500 A SF. The voltage efficiency is calculated by

dividing the ideal thermal neutral voltage (Vtnv)by the actual cell

voltage. Vtn v is adjusted from 1.48 V at STP to 1.590 V at 3000

PSIA and 110° F conditions using Nernst' s equations. Current

efficiency is only slightly affected by trend in temperature and it's

effect on diffusion losses.

m

i

38.
i

4k

_w

r.

_ UNITED

TECHNOLOGIES FINAL REPORT • IPTA-007-91

Expressed as current loss, calculated diffusion ranged from 11 amps

at 274 ASF and 100 ° F to I6 amps at 1500 ASF, 130 ° F(83%--95%

current efficiency). Operation at standby conditions required

balancing diffusion with current. The controller was programmed to

increment or decrement current within range to maintain system

pressure and cell stack charge. Agreement with calculated diffusion

values were achieved within +2 amps.

Power required to drive the electrolysis reaction is given in

Figure 2.19. Calculated as the product of current and total stack

voltage, the power ranged from 1.8 kW at minimum, 6.3 kW at

nominal to 13.4 kW at emergency gas generation rate.

Gas purity, measured 20 minutes after start-up when 3100 PSIA

pressures are reached, was better than 99.5% for both hydrogen and

oxygen.

The cell stack maintained full integrity during all phases of testing,

proving the design adaptation from the US Navy hardware to

prototype propulsion electrolyzer to be successful. The cell stack

maintained all internal and external seals from assembly through

completion of testing. Current and cell voltage feed-throughs

functioned well with no overheating, shorting or leak failures. No

internal shorts or leaks developed between cells or between a cell

and ground.

Test logs, data disks and records are available separately.

summary of test runs is given in the Source Documents section.

A

2.3.3.2 Test Fixture Performance. The Special Test Fixture

accommodated all ceil stack and test system goals outlined in the

SOW. At the time of delivery to NASA/JSC, the total system had

accumulated in excess of 110 operating hours at full pressure.

Problems with the process water filter and high pressure liquid level

sensing would be resolved by NASA/JSC and Hamilton Standard after

installation at JSC Thermochemical Test Area.

A summary of test runs, including commentary as to the

development of the test fixture is given in the Source Documents

section. The Operation and Maintenance Manual (IPTA-033-90)

includes description of the system and the level sensor solution.

m

39.
_ UNITED

TECHNOLOGIES

FINAL REPORT - IPTA--007-91

2,3,4 Delivery to JSC

A total of seven packages were prepared for shipment to NASA-JSC

via government bill of lading. The shipment consisted of the cell

stack, the test fixture fluids package, the test fixture electrical

support console, the test fixture high pressure pump, the test fixture

control console and computer, cell stack power supplies, control

cables, power cables, low pressure water line, spare regulator soft

goods, manuals and documentation. All items were crated on

May 5th. The shipment left the dock on May 8th and was received

in good condition at the PPD-TTA.

.____

= :

r-,

2.4 IPTA Installation and Operation

NASA/JSC completed installation of the system in the IPTA test

facility and initiated test in June 1990. Hamilton Standard provided

fieId support to the subsequent tests. As of this writing NASA has

logged in excess of 740 hours on the SPE-Propulsion Electrolyzer and

plans to continue operations in support of H-O thruster testing.

2,4,1 Installation

NASA personnel uncrated the shipment and located the system

components in the Building 356 facility. The cell stack and test

fixture fluids package were placed in the 356E test cell with the

existing IPTA test equipment. The high pressure water feed pump,

cell stack power supplies and the test fixture electrical support

console were located in the compatibility cell adjacent to the test

cell. The control console and computer were located in the Building

356 control room approximately 300 feet away. This system

component layout is shown schematically in Figure 2.20.

On-site contractor support was initiated on May 23rd to assist NASA

in final system installation. By May 31st the cell stack was installed

and water had been circulated through the oxygen side of the system

using the test fixture circ pump and water loop. All control lines

were installed and checked out, and the control computer was

verified operational with all sensors operating. Cell stack resistances

were measured and shown to correlate to the readings taken prior to

shipment, thereby indicating no drying or mechanical damage to the

cell stack due to shipment or storage.

m

40.
.=.

it==.=."

b=.

w

_ UNITED

TECHNOLOGIES FINAL REPORT • IPTA--007-91

A test fixture AC power relay box was built and installed to provide

the NASA test operator with a manual power shut down of the

system in the event of a controller failure. This replicated a similar

device in place at the contractor's test facility during the 100 hour

test.

320 FT TO CONTROL ROOM

DATA LINES TO COMPUTER

HIGH

PRESSURE

WATER

PUMP

I

CELL STACK

POWER

SUPPLIES

16-CELL

STACK

AND TEST

FIXTURE

EXISTING IPTA EQUIPMENT

Figure 2.20 Installation Schematic, NASA/JSC Bldg 356E

w

NASA completed final plumbing installation of vent lines. A Test

Readiness Review (TRR) was called by NASA . Prior to the TRR the

completed NASA installation was inspected by Hamilton Standard.

The cell stack power supplies were phased and calibrated. The

oxygen in hydrogen sensors were found to be malfunctioning due to

a corroded electrical connector at the sensor. The hydrogen /

41.
b

r..2

_i: !

w

_ UNITED

TECHNOLOGIES

@A_rll_"@i_ FINAL REPORT - IPTA-007-9I

nitrogen vent gas line was recommended to be increased from 3/8"

to 1/2" diameter to alleviate back pressure during system

depressurization.

The TRR was held on June 19th as scheduled. NASA Safety

questioned the absence of dedicated relief valves in the oxygen side

of the test fixture. Hamilton Standard was able to satisfy the review

board that adequate relief capability existed with the redundant

back pressure regulator DBPR210-2 and the bypass vent valve AOV213. The review board approved initiation of system testing and

accepted the NASA test plan. The test plan included a leak test at

200 PSI following operation at 3000 PSI, all to verify system

integrity.

2.4.2 NASA Operation

The first NASA start-up at full pressure of >3000 PSI was achieved on

June 21. Operations during June resulted in at least twelve hours of

full pressure operation of the cell stack, the longest run lasting four

hours. Additional run time was curtailed due to facility problems. In

subsequent months, a series of test fixture and NASA test facility

anomalies limited operation of the system to several hours at a time.

Major events and problems were

w

w

• High Pressure optical sense liquid level sensor malfunctions

• Gas mixture sensor failures and moisture problems

• Recirculation water filter (F501) fouling

• Lightning strikes on the facility

• Limited data storage for long term operation

Resolution of these problems eventually led to a reliable system

capable of unattended operation. NASA proceeded toward their goal

of 500 hours continuous operation. The longest run to date is 383

hours, ended by yet another lightning strike. NASA has logged over

740 hours at full pressure as of this writing.

2.4.2.1 Start-up The first attempts to start up the system on

June 20th and 21st were hampered by a failed seal on the water

drain valve V218. The valve was capped off until a repair could be

made. Full pressure of >3000 PSI was achieved on the next attempt.

Operations during June resulted in at least twelve hours of full

pressure operation of the cell stack, the longest run lasting four

hours. Additional run time was curtailed due to facility problems.

42.
= :

. r

_ UNITED

TECHNOLOGIES

_1]_7@_ FINAL REPORT • IPTA--007-91

On June 22nd, the system was operated for two hours at 3000 PSI,

shut down, and the nitrogen supply regulator turned back to 2000

PSI. The system was then operated at the reduced pressure while

personnel examined the system for leaks. This satisfied the proof

and leak test called for in the NASA test plan.

2.4.2.2 Level sensor resolution. The liquid leveI sensor

problems were resolved through a cooperative NASA-HS

development of an electrical conductivity probe to replace all high

pressure liquid level sensors. As shown in Figure 2.21, the principal

of operation is a measurement of water conductivity using a low

level alternating current. A single insulated electrical probe is used

as one conductor; the wall of the phase separator is the other. When

the probe is dry, no current passes. When the probe is wetted, the

AC current flow is detected. The design is such that a retrofit of the

existing optical-sense level sensor was easily accomplished. Probe

and flange materials provided by HS for O2 level sensing were

Inconel, ceramic and Viton. Stainless steel (3169S) was

recommended for hydrogen side use.

Oxygen

Probe Separator

,----,

I

1 Amp

I Transformer I

r,= =. m -= i

.__ Full-wave I_ Bridge _"

1

To

H P 3497

24vdc

Figure 2.21 Replacement Liquid Level Sensor

m

43.
w

w

= ;

w

w

_ UNITED

TECHNOLOGIES

M_MI]I_@_ FINAL REPORT • IPTA--007-91

2.4.2.3 Gas mixture sensor problems. Gas mixture sensors

have caused some problems. Both H2 in Oz and 02 in H2 type sensors

have experienced water droplet fouling leading to false mixture

sensing. TFE hydrophobic membrane ( effective at HS) has been

supplied by along with installation and calibration instructions to

minimize the problems. NASA has procured replacement sensors.

One of the O2 in H2 sensors (GA317-x) showed cracks in the plastic

housing, indicating pressures in excess of the 50 PSI design. NASA

resized the hydrogen vent line with a larger diameter to prevent

overpressurization. As of this writing, resolution of moisture

problems has not occured and NASA has elected to remove the

sensors for closed test cell operation.

2.4.2.4 Reconfiguration of the data storage NASA/JSC has

experienced some difficulty with the data retrieval procedures and

have expressed an interest in alternatives to storage on the computer

hard disk, which limits total storage to approximately eight hours at

a rate of thirty records per minute. NASA and HS cooperated on a

solution which included installation of a 160 Mbyte hard disk and

upgrade of the system controller software and BASIC operating

system. The controller now can log data for seven days continuous at

the rate of one record every 10 seconds. Data retrieval and backup

is accomplished via simple MS-DOS file commands. Hamilton

Standard provided software revision and field support for

installation and check-out.

2.4.2.5 Lightning Strikes NASA/JSC-TTA facilities have

been hit with several electrical storms which have adversely affected

the intelligent pressure transmitters installed on the test fixture.

NASA has twice repaired electronics in the Paroscientific absolute

pressure transmitters, resulting in delays. To date, no isolation

method to prevent future occurrences has been identified.

2.4.2.6 Revised documentation Hamilton Standard has

issued a revised operations manual (IPIA-033-90) and revised

software listing and requirement specification (IP'I'A-054-90) to

document changes and updates to the test fixture.

m

44.
.,...a

w

N

= =

I

r

I

I

_ UNITED

TECHNOLOGIES FINAL REPORT • IPTA--007-91

3.0 SPE-Propellant Generator Conceptual Design

This section summarizes the the Conceptual System Design (CSD)

study conducted by Hamilton Standard in 1990. The System Design

Review (SDR) was delivered to NASA/JSC in early 1991. Concepts

were developed for a flight-type high pressure H2/O2 SPE-Propellant

Generator system for Space Station propulsion. The study emphasis

was best reliability for 5-year life based on projected 1995 available

technology (1990 start). Key trades and key technology areas for

development were identified and a baseline system was concepted.

3.1 Trade Studies

The technology baseline was IPTA demonstrator system delivered

under this contract. The trade studies built upon previous trade

studies conducted for NASA, MDAC and for Hamilton Standard

internal use.

As a guideline for the trade studies,

absolute, primary and secondary criteria for

trade study selection were established

based on Statement of Work definition and

current knowledge of the Space Station

architecture.

Absolute criteria are defined by the SOW.

Gas production requirements are 2 P P H

nominal with a 0.6 to 4.0 PPH range. Product

gas is to have less than 2500 PPM impurities

with a dew point at point of use of -100 ° F.

The system must deliver 3000 PSI gas to

storage. The operating environment will be

zero-G, space vacuum, with a temperature

range of from +150 to -20 ° F. System life is

to be 30 years stack, major components, 5

years to replacement. The basic duty cycle

is 54 min on / 36 min standby, with 3

minutes to reach full power. Electrical

Efficiency is to be better than 70% at B.O.L.

The environmental goal is to be nonventing. Finally, no two independent

failures can harm crew or other systems.

Performance

Safety I

Power j

Weight I

Volume I

Commonality

Flexibility I

Margin 1

Growth I

Potential I

Figure 3. I

Trade Study Criteria

45.
- t

: E !

v

r

m

_ UNITED

TECHNOLOGIES FINAL REPORT • IPTA-007-91

Figure 3.2 illustrates the basic SPE-Propellant Generator (SPE-PG)

interface as derived from the absolute criteria and 1990 Space

Station PDR information. The two-phase ammonia coolant loop

temperature had not been decided on, so the higher temperature

(62+5°F) was used for these trade studies. Also, the nitrogen utility

pressure available to the system is likely to be in the range of 600--

800 PSIA, much lower than that used in previous systems.

PARAMETER

Power

Feed Water

Nitrogen

Coolant

Oxygen

Hydrogen

COMMENTS

120VDC

Hygiene Grade TBD

Press 30:_?. PSIA

Temp 70_:5 °F

Press 600-800 PSIA

2-E_ NH3

Hfg = 500 Btu/Ib

Temp = 62__+5°F or 35°F

3000 PSIA

-100°F dew point

<2500 ppm impurity

3000 PSIA

-100°F dew point

<2500 ppm impurity

Power ==============================::::::::::::::::::::::

-'-t_ili !:_iil:/:::::::::::::iiiii!i::i_i_!i!iiiiiiiliiiiii_ii2iii:: .,. O2

N2 ....Ki_i_i_ili_i_ii_;_ii_i_iiiii_i_iliiii_ii_i_i_i_iiiii:_iiiil

Feed H2_.O__[_::_i_i_i_ 2:::::::::::::::::::::::: "_ _N_ 2

2-_NH3 ti_i_!_!_®i!_ I "

Control_ _Iii!i,,__ '_::::: _:'_iii_i_i_i_i_i_i_i_i_i{!i_iiii_{iii_ii_iiiiiiiiii_!_!_iiiiiiii_i i!iiiiil i!_ i ign{

Figure 3.2 Interface Definition

Primary study criteria considered a maintenance EVA period of 5

years, requiring system reliability to be 5 years. Resupply periods

were assumed to be every 90 days. Secondary criteria considered

component commonality, growth potential and maturity.

The following major trades were considered during the conceptual

study:

3000 PSID (One-way) DOMED STACK vs Present Design

600 PSI GN2 SAVE SYSTEM vs High Pressure Supply *

NON-REGENERATIVE vs Regenerative Driers*

"Non- Active" TEMP CONTROL vs 120°F Active Control

PASSIVE FREEZE PROTECTION vs Active Freeze Control

DOME LOADED REGULATORS vs Electronic Regulators *

WATER FEED PUMP Location

Combined WATER FEED, TEMPERATURE, DRIER $ Study

Mean Time Between Failure (MTBF) configurations

46.
r_

7---"

_m

_ UNITED

TECHNOLOGIES

FINAL REPORT ° IPTA-007-91

Several of these trade studies ( marked with an *) were conducted as

part of an independent study conducted by Hamilton Standard as an

evaluation of QFD product development methodology. The HS

sponsored "QFD - High Reliability SPE-PG" study occurred prior to

award of the CSDR study contract modification. The results of the

QFD studies were reviewed and adopted or revised for the present

CSDR.

A modular system schematic that incorporates the major study

recommendations and meets the study criteria is given in Figure 3.3.

The following sections provide an overview of the CSDR trade study

results as they relate to this schematic. The CSDR trades are

discussed in greater detail in the System Design Review Presentation

(IPTA-055-90).

I

|

LOW

PRESS GN2

SUPPLY

3100 PSI

02

3OO0 PS

H2

BUBBLE

ACC

REF

FEED WATER 3100

ACC PSI

\

\

GAS/WATER

HEAT EXCHANGER

POWER

_mONER

ASSEM6LIES

IL

FEED WATER SUPPLY \ "_==,.-

PACKAGE _ P

Figure 3.3 SPE-Propellant Generator Modular Schematic

=

47.
w

r

;-.

k..,.-

_ UNrrED

TECHNOLOGIES

FINAL REPORT • IPTA-007-91

3.1 ,1 3000 PSID (0ne-way) DOMED STACK vs Other Designs

The cell stack is the primary component in the gas generator system.

It's configuration determines the requirements for the remaining

components. The cell stack trade study considered three options:

1. Phase 1 IPTA design, requiring 3150 PSI nitrogen dome pressure and a pressure

hierarchy system to control membrane BP to within 700 PSlD

2. Enhanced domed cell stack capable of full 3000 PSlD oxygen over hydrogen

membrane differential pressure ('O2>H2 AP*)

3. Enhanced cell stack, undomed, capable of full 3000 PSIDin either direction and

overboard ("full 6P*)

Option 2 was selected based on maturity, projected 1995 availability,

reduced nitrogen consumption, and system reliability enhancement

criteria. The cell stack basic cell design, with the exception of an

enhanced hydrogen side membrane support, would retain the same

proven components of the existing design. High A P designs are

already under development for other products. (Differentials as high

as 3000 PSID have already been demonstrated in similar hardware

and 5000 PSID in specialized electrochemical gas compressor

hardware) The ability of the cell stack to withstand the total loss of

hydrogen pressure without damage allows the electrolysis pneumatic

system to be simplified. Previous systems, including the recently

delivered Special Test Fixture, have a cross-referenced system of

oxygen, hydrogen and nitrogen pressure regulators and relief valves

that are designed to maintain the proper pressure profile in any

event. The _O2>H2 AP" stack allows elimination of this elaborate

system in favor of a fixed oxygen regulator, an O2 referenced

nitrogen system and a N2 referenced hydrogen regulator. The

simpler system with fewer functions and components enhances

reliability.

A qualified "full AP n domeless cell stack (Option 3) was not estimated

to meet the 1995 readiness criteria. It would be an attractive choice

for a future, simpler system as it would require no nitrogen or

nitrogen-referenced pressure controls.

,1.2 600PS!GN2$AVE_;Y_;TEMvs i_Hj.gh.Pressure Supply

Nitrogen is required for cell stack dome pressurant and for

pneumatic reference to the H2 regulator; previous requirements for

N2 purge/backfill of the H2 side during system shut down were

eliminated by the "O2>H2 AP" cell stack trade study selection.

Information from the 1990 Space Station PDR indicated that nitrogen

48.
.....

=

,!.,i.

= .

thin..

_ UNITED

TECHNOLOGIES

FINAL REPORT . IPTA--007-91

would be available for other equipment in the pressure range of

600--800 PSIA; higher pressure would require a special gas source.

The HS QFD-High Reliability team studied an accumulator system

whereby low pressure GN2 would be compressed by generated 02 to

the required 3100 PSIA pressure. On system depressurization, the

nitrogen is "saved" as it is allowed to expand back into the

accumulator. The required nitrogen volume would be minimized by

filling voids in the cell stack pressure dome with an inert, lightweight

material. The concept is depicted in Figure 3.4.

The present CSDR study estimated that the total GN2 pressure volume

could be reduced to 120 IN 3 and that a suitable "boot-strap"

accumulator would require 0.8 FT 3 of space in the SPE-PG package.

On the negative side, up to 6 hours are required ( 2 PPH H20 rate) to

pressurize the accumulator. Also, a large high pressure accumulator

has to be qualified previous assemblies of this size are commercial

devices for hydraulic service.

LOW

PRESSGN2

SUPPLY

BOOT 1¢"_'_ :•; <: i: :.:_

STRAP _k.u_. ::--: :::i

ACC .&.. i eO0

•_ iPSJ

REF

PSJ i

Figure 3.4 Nitrogen Save System

An alternative 5-year high pressure supply was compared on a tank

volume basis. Assuming that the high pressure gas was not

recoverable (vented) and that the SPE-PG experienced a complete

depressurization and restart every 90 days, a 6000 PSI GN2 supply

tank volume of 2.1 FT 3 would be needed. 16.5 LBS of nitrogen would

be vented in 5 years. System start-up pressurization to 3100 PSIA

49.
= :

_ UNITED

TECHNOLOGIES FINAL REPORT • IPTA-007-91

without a boot-strap accumulator would be comparable to the

Phasel Special Test Fixture (<15 minutes).

With the criteria of low supply pressure and a goal of no venting, the

600 PSI GN2 Save System is selected. It requires no significant

resupply, requires no venting, is smaller in volume than a special

supply and is compatible with the planned GN2 utility. If venting

were allowed, however, a simple special high pressure tank may be

more reliable than an accumulator.

w

E _

m

w

r_

3.1.3 NON-REGENERATIVE vs Regenerative Drier_

Gas drier beds for the removal of water vapor from product gas

streams would make use of a molecular sieve material (Linde 13X).

The product gas is dried to a low dew point (-100 ° F) so that

moisture does not condense in gas storage tankage, gas transmission

lines or in the thruster.

The previous drier concept (1988 IPTA proposal HSPC 88T14) was a

pressure swing regenerable drier system. One drier would be

valved on-line while the second one would be purged using a vent

stream expanded to low pressure (200--300 PSI). The drier system

could be made small, based on the frequency of cycling. The wet

purge stream, representing 3--5% of the gas produced, had to be

disposed of in some fashion.

The present study examined the use of a simple non-regenerative

drier sized for 5 years before replacement. A non-regenerable drier

would eliminate the switching valves, pressure swing stress and

purge gas waste features of the regenerable system.

Non-regenerable drier size is directly related to water content of the

product gas streams, which is determined by system gas generation

temperature and pressure. Water load imposed on the driers is five

times less at 70 ° F than at 120 ° F. Conversely, if system pressure is

allowed to vary from 300 to 3000 PSI, the water load is increased

250% over constant 3000 PSI operation.

The non-regenerative approach was selected in the current study for

reasons of simplicity (higher reliability) and elimination of a purge

stream. An effort to reduce gas generation temperature is required

so as to minimize drier size.

w

--7

50.
L_

L

Z :

r

_ UNITED

TECHNOLOGIES FINAL REPORT * IPTA-007-91

If the no venting criteria can be relaxed and if size becomes more

important, regenerable driers should be reconsidered for their size

advantage. Regeneration studies at NASA/JSC showed temperature

and vacuum to be most effective in regenerating molecular sieve

beds.

3,1 ,4 _ Active" TEMP CONTRQL vs 120°F .Active Control

Previous concepts (1988 IPTA proposal HSPC 88114) showed the most

efficient cell stack temperatures for gas generation to be 110--120 ° F.

Alternatives were considered for the present CSDR trade because of

the non-regenerable drier trade study results and because of the

goal of greater system reliability and simplicity.

The heat sink for rejecting waste heat is the two-phase ammonia

coolant loop. As of the 1990 Space Station PDR the operating

temperature of the heat sink was expected to be 62+5 o F. A noninvasive means of transferring heat to the 2-_ NH3 loop is required

by Space Station PDR guidelines; this mandates use of a cold plate.

: WATER | L

...... ,..... t

I-__4_Ea,Ta_t ..... z_.... F-_r ....

I 1

ITi.,oo2o- f,l 79 I 9s

HEAT EXCHANGER

POWER

CONDITIONER

ASSEMBLIES

62'1:21;}

ammonia

2 PPH B01

Figure 3.5 "Non-Active" Thermal Control

A "non-active" thermal control system was concepted to meet the

study criteria. A heat exchanger is positioned within the 02 side

water recirculation loop between the cell stack outlet and the O2/H20

phase separator inlet. Gas exiting the phase separator is saturated

with water vapor at the bulk water temperature, so by cooling the

two-phase stream prior to phase separation, the lowest dew point is

achieved. The heat exchanger is configured as a flat plate to

interface with a Space Station mounted ammonia cold plate. A

specific cold plate configuration had not been specified by Space

51.
7

_ UNITED

TECHNOLOGIES FINAL REPORT • IPTA-00%91

Station PDR, so a multi-layer plate 2.5' by 4' was concepted.

Figure 3.5 shows the concept schematic and the expected operating

temperatures at beginning of life (BOL) and end of life (EOL). The

average operating temperature and oxygen gas dew point is 85" F.

The minimum temperature possible approaches the NH3 loop

temperature of 62" F. This low temperature during Standby

operation reduces diffusion losses to less than half of the diffusion

loss at 120 ° F.

3.1.5 PASSIVE FREEZE PROTECTION vs Active Freeze Control

Passive and active methods of preventing water freezing of inactive

SPE-PG systems stored on Space Station were examined. The

simplest, most efficient method requires only a thin space suit type

insulation sheath with selective use of a coating to adsorb solar

energy.

w

OF

250

200

150

100

50

°

Copper foil

/

/

I Oxidized Aluminum-75°F

_"_ Sandblasted SS

- = Freezing ............

! I I I I I I

0 1 2 3 4 5 6 7

TIME- DAYS

7

Figure 3.6 Performance of Thermal Coatings

52.
w

_ UNITED

TECHNOLOGIES FINAL REPORT • I1:¢FA-007-91

A transient thermal model was written for study of electrolysis

system freeze protection. The system transient model assumes high

internal thermal conductance ( a uniform internal temp), a 90 minute

low earth orbit (54 min sunlight), and the conceptual design system

rectangular geometry ( absorbtion to radiation view factor = 1/4 ).

Results show that a selective outside surface coating is sufficient to

prevent electrolyzer system freezing when deactivated. The outer

coating should have the proper radiation absorbtivity/emmissivity

(a/e) ratio for system orbit, weight, shape and attitude to sun and

earth. Figure 3.6 shows the estimated performance of three different

surface coatings. Oxidized aluminum ( a/e = 2.7) proved to be the

correct choice, maintaining an internal temperature close to 75 ° F for

days (or years, if required). To retain absorbed heat during solar

occlusion, the use of space suit type thin insulation (0.06 BTU/FT2-°F)

is needed under the aluminum coating.

3.1.6 DOME LOADED REGULATORS vs Electronic Regulators

Pressure control of the generated hydrogen and oxygen and

maintenance of the pressure dome nitrogen blanket was evaluated.

The standard method of pressure control in high pressure SPE-water

electrolysis systems is a system of cross-referenced dome-loaded

pressure regulators. Nitrogen is the common reference gas.

Electronic-variable pressure regulators (EVPR) are a new class of

control devices that have been demonstrated for propellant gas

pressure reduction from 300 to 3 PSI. They eliminate the need for

nitrogen reference gas.

Dome-loaded regulators were retained for the CSDR study because

• Dome-loaded regulators have higher maturity for water electrolysis than EVPR

• GN2 dome reference gas isalready available from cell stack trade

• Pneumatic system controls even in lossof power

• 1995development status criteria

• High pressure materials compatibility with present EVPRmagnetics designs

The selection of the "High O2>1-t2 AP" cell stack allows use of a simple

back-pressure regulator for oxygen. Referenced regulators are still

needed for hydrogen and nitrogen pressure control.

For a post-1995 SPE-PG that would use a domeless cell stack, the

EVPR would have to be developed.

w

53.
m

w

m

_=

_=

t,....

_ UNITED

TECHNOLOGIES FINAL REPORT - IPTA-007-91

3 .1 .7 WATER FEED PUMP I,._O...¢.._,..I.._.

Studies of oxygen-pressurized batch water feed (non-venting and

venting approaches) and integral continuous feed pumps were

conducted by the HS QFD-High Reliability team. The studies

concluded that, while batch feed could be made to operate at a lower

power penalty than continuous feed (3.5 vs. 21 kW), the size and

complexity (690 LBS m 17 components vs. 41 LBS m 5 components ) of

batch feed did not trade well. The team selected continuous feed but

expressed concern that the continuous feed pump would require a

high level of maintenance. A reliable, low maintenance high

pressure feed pump was identified as a critical development item.

The present CSDR study team considered an option: remote location

of the feed pump off the external package to inside the pressurized

Space Station habitat. Internal location of the feed pump eliminates

any need for EVA on this item, minimizing concerns over reliability

and maintenance. The CSDR team surveyed the Work Package II

contractor (McDonnell-Douglas Aerospace) and NASA/JSC and

received concurrence as to the acceptability of 3000 PSI water

generated in a pressurized node. This concept was then incorporated

into the SPE-PG conceptual design.

3.1.8 Combined WATER FEED. TEMPERATURE. DRIER __

Cost sensitivity trades were conducted on the interrelated water

feed, system temperature and drier trades. Five cases, four with

non-regenerable (5-year) and one with a regenerable drier system,

were considered:

® Constant Water Feed / 100°F stack exit / 80°F 02 phase separator inlet

® Batch Water Feed / 100°F stack exit / 80°F 02 phase separator inlet

® Constant Water Feed / 120°F stack exit and 0 2 phase separator inlet

_] Batch Water Feed / 120°F stack exit and 02 phase separator inlet

® 90 day Regenerable Driers; vent to vacuum, heat to 350 ° F for 8 hours to

regenerate/ Case • conditions

Relative weight, power penalties for launch and resupply were

compared using primary criteria cost penalties derived from the

1990 Space Station PDR. Table 3-1 presents a case summary of

weight, energy and cost associated with launch and 30-year

maintenance or resupply for the five cases.

54.
i :

_ UNITED

TECHNOLOGIES FINAL REPORT • IPTA-007-91

Results show Case ® is the lowest weight, largest power, and lowest

power+weight penalty case of the four non-regenerable drier

systems. Regenerable driers (Case ®) have a lower weight penalty

(40% lighter) and only slightly lower power+weight cost (5%) in

contrast to the best non-regenerable system, Case ®.

TABLE 3-1

CASE SUMMARY

n

30-YR WEIGHT, POWER, COST PENALTY FOR DRIERS, TEMPERATURE AND WATER FEED

CASE LAUNCH

30 YR ELECTRICAL 30YR POWER 30YR WEIGHT 30YR PWR+WT

WEIGHT (LBS) ENERGY PENALTY PENALTY PENALTY

RESUPPLYTOTAL WT (KW-HR) ($M) ($M) ($M)

O 445 3575 4020 38894 8.87 27.50 36.37

1527 3670 5197 28908 6.59 34.10 40.69

780 5248 6028 9986 2.28 41.00 43.28

2245 7256 9501 0 0.00 63.10 63.10

149 2093 2242 83440 19.00 15.50 34.50

I IIIIIIII

Launch weight = driers, feed pumps or batch bladder tanks, structural support

Resupply weight=driers (life=5-years), associated valves, feed pump (life=l year)

A power penalty of 110 watts was assessed the 80°F cases for stack voltage inefficiency

A power penalty of 38 wafts was assessed the constant feed cases for the feed pump

Power is required to heat the regenerable driers every 90 days, 500°F for 8 hours

= 1

m

The CSDR team had previously selected the Case ® system based on

reliability and non-venting criteria. For future trades where weight,

volume are of greater concern and venting to space vacuum for

regeneration is allowable, then Case ® should be reconsidered.

w

m

3.1 .9 Mean Time Between Fail0re (MTBF_ configuration_

Using established aerospace criteria, the functional SPE-Propellant

Generator system schematic has an MTBF of 8 months (see Source

Document section for schematic). The SPE-PG MTBF may be

improved to 2-1/2 years by implementing the following measures:

- Redundant control instrumentation - Redundant system relief valves

- Bifilar windings on solenoid valve coils - Redundant control units

- Redundant circulation and protonic water pumps

- Redundant H2, 0 2 pressure regulation modules

- Triple redundant cell stack power converter controller section, one additional

power converter stage (5+ 1)

55.
_ UNITED

TECHNOLOGIES FINAL REPORT . IPTA-007-91

To achieve the goal of a 5-year MTBF, a single propellant generator

unit must include two parallel fluid operating systems, less the cold

plate / heat exchanger assembly. The feed pump is not included in

the MTBF calculations as it is a separate unit serviced without EVA.

u

Basic:

2-1/2 year:

5-year:

1733 LBS, 8 mo. MTBF I +

Baseline modular system I

41LB H20 module Feed I

2043 LBS, 30 mo. MTBF

2X Regulators, pump, control

modules; 5+1 power stages

•I- J41LB H20 module Feed J

1100 Fluid section LBS, 30 mo. MTBF

1100 Fluid section LBS, 30 mo. MTBF

.............................................. + t-t20 module

1186 LBSj60 mo MTBF

Electronics, HX/Cold plate

w

i

Figure 3.7 MBTF Configurations

Figure 3.7 is a diagram of the 8 month, 2.5 and 5-year configurations.

The 2.5-year configuration was the subject of a conceptual

mechanical design packaging effort described in Section 3.2.

3.2 Conceptual Design and Layout

The SPE-Propellant Generator primary function is to produce 3000

PSIA dry (-100 ° F) hydrogen and oxygen for Space Station propulsion.

To accomplish this, it must perform these internal functions:

. Electrolyze water to produce hydrogen and oxygen

• Deliver feed and cooling water to the electrolysis stack

• Separate gas and liquid water

• Dry the product gases

• Reject stack and system waste heat

56.
w

rm.

m

,J.,

_ UNITED

TECHNOLOGIES

lllAl!lll=_@ll

FINAL REPORT • IPTA-007-91

• Maintain pressure control

• Manage protonic water

• Conserve pressurant nitrogen

• Maintain pressure hierarchy and system limits for safety

The Modular Concept SPE-PG shown in Figure 3.3 is designed to

perform these functions. Component modules and major components

have been selected to perform the internal functions required.

A mechanical and electrical design package was concepted for the

SPE-PG in consort with the results of the system trade studies. The

total system package consists of two ORU's (Orbital Replacement

Units): the external mount Generator package and the internal

mount Feed Water package. The Generator ORU consists of a cell

stack / gas separator module, recirculation and protonic water

modules, pressure regulation modules, H2 and 02 driers, four

accumulators, electrolysis power conditioner, control electronics, and

a heat exchanger / cold plate assembly. The Feed Water ORU consists

of a 3100 PSI water feed pump, a valve and sensor module, a feed

water cleanup bed, and control electronics.

_,2,1 System A_ributes

The SPE-Propellant Generator conceptual design features the

following attributes as a result of the trade studies"

• 600 PSI N2 BOOTSTRAP SYSTEM

• UQUID ANODE FEED

• DOMED STACK FILLEDWITH N 2

• STACK OPERATES COLD - 85°F INLET TEMPERATURE

• "Non-Active" TEMPERATURE CONTROL

• DOME LOADED PRESSUREREGULATORS

• OPERATING PRESSURE3100 PSIA WITH 02 MAINTAINED ABOVE H2

• NODE-MOUNT FEEDPUMP CAPABLE OF 3100 PSIHEAD RISE

• PROTONICALLY PUMPED WATER ISSTRIPPEDOF H2 AND REClRCULATED

INTO THERECYCLE LOOP

• NON-REGENERABLE DRIERSARE USED (OPTION CONSIDERED)

• CELL STACK CAPABLE OF 3000 PSID02 >H2

57.
_ UNITED

TECHNOLOGIES

I_1]1_@1_

FINAL REPORT . IPTA-007-9I

3.2,2 System Packaging

One Feed Water ORU and two variations of the Generator ORU were

packaged using mainframe CAD for 2-D and a personal computer

modeling program for 3-D representations. The Generator ORU

representations include electronics and power modules as they reject

heat to the cold plate.

.,, _

w

"L :

m

3.2.2.1 Baseline Concept Figure 3.8 is a perspective view of

the Generator ORU baseline package concept. The non-regenerable

driers are the largest volume pressure vessels. The N2 boot-strap

accumulator, feed water and protonic water recovery accumulators,

and the cell stack/phase separator module are adjacent to the driers.

Mounted on the heat exchanger/cold plate is the stack power supply,

the control electronics, and component modules for pressure

regulation and water management. The Generator ORU dimensions

are 21 by 30 by 104 inches. The estimated mass of the ORU is

2043 LBS based on a two and one-half year MTBF configuration.

Figures 3.9 a--f orthographic views of the Generator ORU baseline

package.

A mass summary of the baseline concept subassemblies, including

mass multiplying factors to achieve 2.5 and 5 year MTBF levels, is

presented as Table 3-2. The factors derive from the level of

component redundancy.

TABLE 3-2

Baseline and Regenerable Concept Mass Summary (Units in LB-M)

CELL STACK/SEPARATOR ASSEMBLY

GAS DRIERS

ACCUMULATORS

PRESSURE REGULATION MODULES

RECIRC/PROTONtC WATER MODULES

RECO IER

HX/COLD PLATE

FRAMEWORK/PLUMBING/MISC

8 Month

247 , 1oo

337 too

218 lOO

77 2.0,0

63 2.00

18 1oo

240 ,oo

193 ,is

POWER SUPPLY ( CELL STACK) 250 1.2o

EIB/ MDM/PROTONIC WATER P.S. 90 2oo

FEED WATER SUBSYSTEM 41 too

2.5 Ye0r

247

337

218

154

126

18

240

222

300

180

41

S Year

x 2Do 494 I (2.syt), loo

2oo 674 I o_o

200 436 I 12o

200 308 I 1Do

2oo 252 I ioo

200 36 I I._

1O0 240 I I oo

187 415 I ioo

1.oo 300 I 1oo

1oo 180 I loo

100 _- - - I O0

Regen Drier

Concept

247

34

262

154

126

18

24o

222

300

180

41

Total Wts: 1774 2083 3376 1823

3.2.2.2 Regenerative Concept The baseline Generator ORU

concept adheres to the non-venting criteria through the use of nonregenerable driers and the N2 save system. An alternative package

was assembled to show the mass and volume reduction realized

58.
Z

l

w

_ UNITED

TECHNOLOGIES

SYA@DA_@

FINAL REPORT • IPTA-007-91

through incorporation of regenerable driers and rearrangement. The

2.5 year MTBF baseline Generator ORU was modified with 90-day

size regenerable driers and repackaged bootstrap and bubble

accumulators. This regenerable drier package concept for the

Generator ORU is shown in Figure 3.10. The alternate ORU package

is 21 by 30 by 65 inches and has an estimated mass of 1782 LBS.

Orthographic views of the regenerable drier Generator ORU concept

are given in Figures 3.11 a---c.

A mass summary comparing the optional concept to the baseline at

the 2.5 MTBF level is included in Table 3-2. A 14 FT 3 volume

reduction is effected by the changes (37.9 FT 3. reduced to 23.7 FT3).

3.2.2.3 Feed Water ORU The Feed Water ORU is the same

for both the baseline and the optional regenerative drier concepts.

This unit is to be located inside the habitable Space Station for ease

of maintenance without the need for EVA. The unit is concepted to

operate for 90 days at the 2 PPH rate before change-out of the

cleanup bed. The clean-up bed is a polishing demineralizer and

organics removal bed. Weight of the Feed Water ORU is estimated to

be 41 LBS Power requirement during operation is 38 watts.

Dimensions are 8 x 11 x 28 inches.

Description of Generator ORU components and subassemblies can be

found in the CSDR presentation (IF)TA-055-90) documentation and in

the Source Document section of this report.

3.2.3 E!ectri¢itl __

The SPE-Propellant Generator electrical system requirements are

divided into functional blocks representing control processing,

instrumentation, sensor signal conditioning, effectors and drivers, the

electrolysis power converter (EPC), and H2 electrochemical "stripper"

power processing. The SPE-Propellant Generator electrical system

must also interface with a Space Station Controller

multiplexer/demultiplexer (C-MDM). The C-MDM interfaces with

the Space Station Data Management System (DMS). The C-MDM is

customer furnished.

A conceptual electrical block diagram of the Generator ORU control

architecture is given in Figure 3.13. Control of the Feed Water ORU is

not represented.

59.
= =

_ UNITED

TECHNOLOGIES

FINAL REPORT • IPTA-007-91

l,,.,3,,,._l_ PAGE

COLOR PHOTOGRAPH

4

,%.i

L

HEAT EXCHANGER / GAS DRIERS

COLD/ PLATE E // CELL STACK POWER EL. CTRONICS

SUPPLY' I ,,,_.f ...... / _.l.-_:_.-,." T'-----

¢ %.- 1

_ _.:.-..--.- ..... ..... ,., A

. / \._...._,_ ....s ,............ ....

/ _-,-' ' 2-_ SEPARATOR

MODULE I MASS: 2043 + 41 Ib

i FRAME AND | (for Feed modulo}

INSULATION COMPONENT II M'rBF: 2-1/2 years (OUTLINE) MODULES

Figure 3.8 Generator ORU Package

WATER MODULE

CELL STACK POWER

CONDITIONER PROTONICALLY PUMPED WATER ACCUMULATOR

HYDROGEN DRIER

-TOP-

-LEFTP

I

30"

f

I

CELL STACK AND PHASE NITROGEN

SEPARATOR MODULE BOOTSTRAP

ACCUMULATOR

OXYGEN REGULATOR MODULE

PROTONIC WATER MODULE

HYDROGEN REGULATOR MODULE

Figure 3.9a Generator ORU, Front

60.
,iie

_ UNITED

TECHNOLOGIES FINAL REPORT . IPTA-007-9I

w

--J

#'_ RECIRC PUMP MOTOR CONTROLLER

,iF

c.o__,o._, °_°_7/r '_=w'_"=c

-1. -" Z_t

"i,.. RECIRCULATION WATER MODULE

" CELL STACK POWER CONDITIONER

Figure 3.9b Generator ORU, Top

;-:: 7

HYDR_EN REGULATOR CELL STACK AND PHASE

PROTONiC WA'_R SEPARATOR MODULE

,,ooo,,7 /-,,o0o,, /

/ I I r BOOTSTRAP ACC

\ \ \ I I I.. OXYGENDRIER / NITROGEN

_i \ \ | J _ REGULATION

_ k / L RECOMBINER MODULE

NIC PUMP MOTOR CONTROLLER HEAT EXCHANGER/

COLDPi..A'i:IE ...... _ -- ELECTRONIC INTERFACE BOX (EIB)

,i

_" PROTONIC HYD STRIPPER POWER SUPPLY

Figure 3.9c Generator ORU, Bottom

6].
_ UNITED

TECHNOLOGIES

l_l_l]i_@l_

FINAL REPORT • IPTA-007-91

: =

w

w

BUBBLE ACCUMULATOR

FEED WATER ACCUMULATOR

iCOMB INE R

-TOP.

-RIGHT-

• %

X

CELL STACK AND PHASE "_ HEAT

SEPARATOR MODULE _-- EXCHANGER

/ COLD PLATE

-LEFTBOOTSTRAP ACCUMULATOR

NITROGEN REGULATOR MODULE

Figure 3.9d Generator ORU, Back

=_

w

&

w

C ELL STACK HYDROGEN

__ -FRONTCOLD PLATE ,_ ..... _,

.o.

HYDROGEN

REGULATION

MODULE

BUBBLE

HYDROGEN ACCUMULATOR 7

DRIEFI _ /

NT- _ OXYGEN

f DRIER

-FRO BACKk_.N,TROGEN

SUPPLY

L BOOTSTRAP MODUL E

ACCUMULATOR

Figure 3.9e Generator ORU, Left and Right

62.
--4

"_ UNITED

TECHNOLOGIES

FINAL REPORT * IPTA-007-91

COLOR PHOTOGRAPH

RECIRC MODULE ACCUMULATORS

ELECTRONICS HEAT EXCHANGER !

COLD PLATE .____ ........

AC ,OW. i

! SUPPLY

_T( A VOLUME FROM BASELINE

..--" / ÷j

SIZE: 21 x30 x 65" I

2-_CELLsEPARAToRSTACK/I MASS: I782+ 41 Ib

MODULE I (for Feed module /

I

-

This package concept shows the effect 4

regenerative driers and different compo["

arrangements on package volume /

, +_ ..... .

PRESSURE

If REGULATION

REGEN'ERATIVE MODULES

GAS DRIERS

Figure 3.10 Regenerable Drier Generator ORU Concept

L_

f

.1

30"

1

i

OXYGEN OXYGEN BUBBLE

CELL STACK POWER

CONDITIONER MODULES DRIER ACCUMULATORS

ACCUMULATOR

HYDROGEN REGEN DRIER

HYDROGEN REGULATOR MODULE

NITROGEN

BOOTSTRAP

ACCUMULATORS

CELL STACK AND PHASE

SEPARATOR MODULE

Figure 3.11a Regen, Drier Generator ORU, Front

63.
_ UNITED

TECHNOLOGIES FINAL REPORT . IPTA-007-91

r

HEAT EXCHANGER /

COLD PLATE

T21"

CELL STACK C-MDM

POWER CONDITIONER

/

RECIRC PUMP MOTOR

OXYGEN REGULATION MODULES

OXYGEN REGEN DRIER

ACCUMULATORS

-BACKNITROGEN

BOOTSTRAP

 ou u To. 

RECIRCULATION

W;ET;DRv_;T_ :L_3 CUMU LATO R

Figure 3.1 Ib Regen. Drier Generator ORU, Top

_=r==.

CELL STACK AND PHASE HYDROGEN REGEN DRIER

-LEFT7 _:o_o.,_u_ ---.WATER / SEPN_R_TO_SOULE

O / /.- REGULATION

/ ./ MODULE

-R/G/IT.

ACCUMULATORS

PROTONIC HYD. STRIPPER POWER SUPPLY

\ - ELECTRONIC INTERFACE BOX (EIB)

COLD PLATE

ULATOR MODULES

Figure 3.1 Ic Regen. Drier Generator ORU, Bottom

64.
w

m

_ UNITED

TECHNOLOGIES

_A_IL_@M FINAL REPORT • IPTA--007-91

o__oo 000

IWE,G.T__,I I

[ POWER = 38 W

I DIMENSIONS: 8 x 11 x 28 IN

{. ...............................

Figure 3.12 Feed Water ORU Concept

i

.,...,=

m

3.2.3.1 Control and Signal Conditioning The C-MDM provides

standard signal conditioning for RTD temperature sensors, pressure

transducers, solenoid/relay driver outputs, discrete input/output

(I/O), high and low level analog interfaces, and serial data I/O. An

Electrical Interface Box (EIB) is the Propellant Generator interface to

the C-MDM. Custom sensor signal conditioning is provided in the EIB

where C-MDM standard interfaces are not available. Feed Water

ORU control is managed by a separate, local C-MDM.

Redundant controls are needed to achieve multi-year reliability. The

second C-MDM has a full redundant set of instrumentation and

effector drivers. The primary and secondary C-MDM's communicate

sensor and status information via a serial data link. The primary CMDM has access to equivalent secondary redundant sensor data in

event of a failure in the primary instrumentation set.

3.2.3.2 Electrical Power Two power services are required

to the Generator ORU. A dedicated 120VDC, 16.3 kW service is

provided to the EPC. A second 120VDC, 360W service is provided to

the EIB for an internal logic supply, pump motor controllers, solenoid

drivers, and H2 stripper power supply. The Feed Water ORU

requires a 75W power service in the pressurized node.

i

w

65.
=

w

=

_ UNWED

TECHNOLOGIES FINAL REPORT . IPTA-007-91

155:

Bus

[34O

E3¢3

C-MDM

i

II +

Electrical Interface Box

m

T !!1

redund Power ConverterJ

C-MDM

120 VDC

(16.3 kW peak)

Electrolysis Power

Converter

+

S t"_l RECIRC

_,JI _TOR COmROL

_ PROTONIC

"-'---'--I kJl MOTORCONTROL

_-_H2 Slripper L

_IFFEC3"_

H2 Stripper

Sense Cells

Figure 3.13 Generator ORU Electrical System Architecture

3.2.3.3 Electrolysis Power Converter A modular power

stage architecture concept for the EPC was developed in response to

unique requirements:

• RAPID RESPONSE TURN ON/OFF

• 2 to 15 kW OUTPUT RANGE (Basis: 5-year EOL)

• MAXIMUM RELIABILITY

• 200 W STANDBY POWER OUTPUT (STACK DIFFUSION)

• CONTROLLED OUTPUT POWER RAMPING RATE

• DROP POWER WITHOUT USE OF BREAKERS OR FUSES

• MINIMUM WEIGHT AND VOLUME

• 92% PEAK EFFICIENCY, GOOD LOW POWER EFFICIENCY

• EMI COMPLIANCE

The EPC concept shown in Figure 3.14 features six 3.0 kW power

modules in parallel: five modules to meet the 15 kW output range

requirement and one redundant module for reliability. Individual

contactors and control lines are employed for flexible power module

selection. A single module is used to support the 200 watt standby

66.
L_

• I

L

= ....

_ UNITED

TECHNOLOGIES FINAL REPORT • IPTA-007-91

requirement; additional modules can be brought on-line to support

up to the maximum 15 kW.

A resident EPC controller (EPCC) with built-in diagnostics and it's own

resident programming allows the EPC to respond rapidly to

commands from the C-MDM. An auto-protective "down-program"

drops power output to the electrolysis stack without the use of

breakers or fuses. Critical EPCC circuitry is redundant.

E

B

120 VDC

Electrolysis Powe 1

Converter Controlh [

l:)o_r Co'"l_rol .| ...... c°n:e! ....... M_°ni.._°._._.+. J_

++ ++;

120 VD CELL STACK

ELEC TROL YSIS

(16.3 kW pm POWER

(15 kw Peak)

._ 3.0 kw Power Module

3.0Powerkw Module

3.0 kw

Power Module

3.0 kw

Power Module

3.0 kw

Power Module

3.0 kw

Power Module

Figure 3.14 EPC Concept

The EPCC enables the power supply to respond to rapid changes in

the Space Station power bus, so that the SPE-PG can function off of

so-called "unscheduled" power that cannot be utilized to charge the

Space Station energy storage batteries or operate other loads. SPEWater Electrolyzer cell stacks has demonstrated the ability to

accommodate power surges and transients within seconds.

3.2.3.4 Software Items There are two software configuration

items: the UAS (User Application Software ) for the C-MDM and

67.
J

w

_ UNITED

TECHNOLOGIES

FINAL REPORT • IPTA-007-91

control software for the EPCC. The redundant C-MDMs communicate

via an RS-449 link. Each will have the capability to assume primary

control. One will be commanded "ON" while the other will be on

standby.

Prototype development programs will be written in "C". Commercial

hardware would be used during development to emulate the MDM

interface. Software specifications will have commonality with the

flight design. Flight unit UAS will comply with the Data Management

System (DMS) standards and defined support environments.

_,2,4 Cell Stack / Phage Separator Module

The key module in the SPE-PG is the cell stack and phase separator

module. The cell stack and phase separators are co-located within

the same pressure vessel to reduce size and weight and to take

advantage of the cell-like static phase separator technology currently

under development. A combined cell stack and phase separator

module has been demonstrated at low pressure.

Figure 3.15 is a functional

diagram of the cell

stack/phase separator

module. The oxygen phase

separator removes 02 gas

from the water recirculation

stream. The hydrogen

phase separator separates

gaseous H2 from H20. The

H 2 stripper electrochemically removes any

dissolved H2 remaining,

and the hydrogen sensor

detects any H2 that was not

stripped.

A conceptual cross-section

of the module is given in

Figure 3.16. Features

determined in the cell stack

trade study are seen. Figure 3.15

Cell Stack / (_-Separator Diagram

68.
L _

m

_ UNITED

TECHNOLOGIES FINAL REPORT - IPTA-007-91

VOID-FILLING BLOCK

Block minimiz_

I Manifold plate divides stack and separator sections, allowing

independent assembly or servicing

CELLS

DOME FOR PHASE

SEPARATORS

I

•SIZING CRITERIA- 16CELLS AS INIPTA PROTOTYPE CELL STACK

TECHNOLOGY -UQUID ANODE FEED INA NITROGEN DOME (SAME AS IPTA)

SLIGHT MODIFICATIONS ASSUMED AS FOLLOWS:

f o UTILIZE MANIFOLDING AT FLUID PLATE TO COOL H2/H20 EXIT DOWN TO STACK INLET TEMP.

I

f (REDUCES LOAD ON DRYERS)

• INCREASE FRAME SIZETO REDUCE FREEVOLUME IN THE STACK AND TO REDUCE GAS DIFFUSION

l THROUGH THE FRAME i

i • USETEFLON AT THE EDGE OF THE MEMBRANE TO REDUCE H20, H2 AND 02 DIFFUSION

• DOME VOLUME ISMINIMIZED BYADDITION OF POLYSULFONE PLUGS

i • THEREIS A SMALL AMOUNT OF CATALYST IN THE DOME TO RECOMBINE DIFFUSED H2 AND 02

I • WATER FORMED BY RECOMBINATION OF DIFFUSEDH2 AND 02 IS ABSORBED BYA DESICCANT

0 O2>H2 CROSS-PRESSURECAPABILITY INCREASED TO 3000 PSID

Figure 3.16 Cell Stack / ®-Separator Module

Additional details of cell stack / phase separator functionality

found in the CSDR documentation.

can be

m

3.3 Operating Approach

The SPE-PG is required to operate in a prescribed manner to

accomplish it's mission. Upon installation it may reside in a dormant

state. When commanded to activate, the SPE-PG would proceed

through various operations:

B

69.
_ UNITED

TECHNOLOGIES FINAL REPORT • IPTA-007-91

ACTIVATE FROM A "DORMANT" STATE

PREPARE FOR GAS GENERATION

PRESSURIZETO 3000 PSI OPERATING PRESSURE

GENERATE 3000 PSIH2 AND 02 AT DEMANDED RATES

ENTER INTO 36 MINUTE "HOLD" STATEDURING L.E.O. ECLIPSE

PERFORM WATER, PRESSURE MANAGEMENT

DEPRESSURIZEAND RETURN TO "DORMANT" STATE

PERFORM FAULT DETECTION AND SYSTEM SAFING

k

_-7-_

System operations can be defined in terms of modes and states. The

modes used for the SPE-Propellant Generator are MANUAL, OFF, ON,

and STANDBY. System states of operation exist within each system

mode. Transitions from state to state within each mode and between

modes are predetermined by control code.

IOFFMode I ION Mode I

_ Dormant State -"- j Prepare State

Depre,_surization <--... },_ Pressurization

"N ////,,,_ Process <--._ ',, Fail ._........ ______/.j , _.. \

Fail "_

\ I MANUALMode I ISTANDBY Mode 'Oorm nt S,,e ,o,,,S.,a,e

Fail _ Fai_

( Transitions Irom State to State within each Mode and between Modes are predetermined by control code )

q;;,.,

Figure 3.17 SPE-PG Control Mode and State Transitions

The mode and state control approach conceived for the SPE-PG is

diagrammed in Figure 3,17. The initial state is the Dormant state in

the OFF mode. It is an inactive state where the propellant generator

components are unpowered and depressurized. The controller is

active and the cell stack is in a benign "02 takeover" situation.

System pressure is N30 PSI, set by vent relief valves. Freeze

protection is expected to be totally passive, requiring no power or

control.

70.
=,m#t-

=--._£.

W

m

!

W

_ UNITED

TECHNOLOGIES

M_I_I][L_@_ FINAL REPORT • IPTA-007-91

On activation, control transitions to the ON / Prepare mode/state.

Here, devices are selectively activated to adjust accumulators,

activate pumps, and check system readiness. The water feed control

is activated, governed by water accumulator quantities. Cyclic

operation logic is activated to initiate transfer between STANDBY and

ON modes to accommodate to solar array power cycles as the Station

orbits through light and dark. The nitrogen bootstrap accumulator is

topped off at 600 PSI, if required. Recirculation of water on the O2

side is started and tested. Some anomaly checking is initiated.

On completion of Prepare state, control transitions to the ON /

Pressurization mode/state. The electrolysis system is activated to

pressurize up to 3100 PSI delivery pressure. First, the 02 stack

takeover is reversed electro-chemically using low voltage and

current. Then, gas evolution begins at 2 PPH rate (-180 amps). The

protonic water management logic control activated to work with the

water feed control. As product gas is generated, O2 pressure will

slowly rise to 3100 PSI. O2 pressure bootstraps the N2 in the

bootstrap accumulator up to O2 + 6 PSI (set by accumulator spring).

Most of the fault conditions are being continually checked at this

point. H2 excess pressure may need to vent to maintain pressure

control.

On completion of Pressurization state, control transitions to the ON /

Process mode/state. This is the normal operating mode/state where

the SPE-PG supplies dry 3000 PSI gases to storage. Generation rate

will vary to follow power profile. The supply valves to tanks are

open, process anomalies detection is fully enabled, and load control

logic initiates transfer between STANDBY and O N and varies

production rate according to available power.

STANDBY is a system ready mode, an energy conservation state used

during dark side operation or on command. While in this mode, no

net gas production occurs as cell stack current is controlled to offset

and oppose the diffusion current (-8 amp). All other system logic

controls are active. The expected time distribution in Low Earth

Orbit (LEO) is 54 minutes ON, 36 minutes STANDBY, but other power

profiles such as unscheduled power can be accommodated.

The OFF / Depressuration mode/state is a controlled depressurization

of system in the event of full tanks or OFF mode selection.

Electrolysis continues at the STANDBY rate. The propellant storage

tanks are isolated. The O2 vent valve is controlled to limit the

71.
T

_ UNITED

TECHNOLOGIES

MAB_rlEL_@_ FINAL REPORT • IPTA--007-91

depressurization rate. N2 expands into the bootstrap accumulator as

O2 vents; H2 vents to follow the N2 reference gas depressurization.

When 02 pressure is less than 30 PSI, power is removed from the cell

stack and pumps. Water management and cyclic logic control is

discontinued. Anomaly detection is selectively disabled thoughout

Depressurafion. The system control reverts to Dormont state or Foil

state at completion. Eventually, residual oxygen within the cell stack

module will diffuse to both sides of the membranes, completing an

oxygen takeover of the cell stack.

In the event a critical fault is detected, the OFF / Foil mode/state is

entered. The SPE-PG control is configured such that upon loss of

power or a failure, the oxygen outlet solenoid valve is unpowered

open to allow system depressurization. The cell stack module and

water pumps will be unpowered. The oxygen in the recirculation

loop water will expand into a bubble accumulator designed for that

purpose.

w

3.4 System Development

Certain enabling technologies require further study and earnest

development to bring the SPE-Propellant Generator to the flight

prototype stage. These enabling technologies are listed in order of

importance in Table 3-3. A parallel development effort beginning in

1991 could produce a flight prototype by 1995 at an estimated cost

of $25M (1990 dollars). Additional background information on the

specific items can be found in the CSDR documentation.

w

72.
_ UNITED

TECHNOLOGIES

FINAL REPORT • IPTA-007-91

TABLE 3-3

ENABLING TECHNOLOGY DEVELOPMENT ITEMS

ZERO-G GAS/WATER PHASE SEPARATORS

DEVELOP AND DEMONSTRATE ZERO-G, 3000 PSI OPERATING PHASE SEPARATORS FOR THE

OXYGEN AND HYDROGEN SUBSYSTEMS. USE EXISTING 200 PSI ZERO-G SEPARATORS AND

TRADE STUDIESAS POINT OF DEPARTURE.

HIGH " ONE -WAY" 6P CELLSTACK MODIFICATION

DEMONSTRATE 3000 PSlD OXYGEN > HYDROGEN CELL STACK. POINT OF DEPARTURE IS

EXISTING 700 TO 1000 PSlD STACK. ELIMINATES NEED FOR GN2 PURGE, SIMPLIFYING

SYSTEM. (HAVE DEMONSTRATED UP TO 5000 PSlD IN GAS CONCENTRATOR CELLS)

CONFIRM BEST CELL STACK SIZEIN STUDY OF SSFPOWER PROFILE

(FUTURE DEVELOPMENT WILL RESULTIN DOMELESS STACK)

POWER SUPPLIES

DEMONSTRATE MULTI-STAGE DESIGN. DEMONSTRATE CELL STACK POWER SUPPLY

CAPABLE OF FOLLOWING RAPID CHANGES IN AVAILABLE POWER. ASSESS H2 STRIPPER

POWER SUPPLY REQUIREMENT AND DESIGN. ESTABLISHSSFPOWER PROFILE FOR DESIGN

GAS DRIERS

TRADE OFF HIGHER MTBF, NON-REGEN DESIGN AGAINST LOW WEIGHT VACUUM+HEAT

DESORBED REGEN DESIGN. ESTABLISH VENTING SCENARIO FOR REGEN DRIERS.

DEMONSTRATE RELIABLE HUMIDITY SENSORS.

LONG HFEPUMPS

DEVELOP ClRC WATER PUMP BASED ON UP(GRADE OF EXISTING SHU1-FLEPUMP. DEVELOP

100 PSID PROTONIC WATER PUMP, NON-LEAK 3100 PSI FEEDPUMP

ACCUMULATORS

DEMONSTRATE RELIABILITY AND LIFE FOR BELLOWS AND POSITION SENSORS.

TECHNOLOGIES FOR REDUCED SIZEAND WEIGHT.

REVIEW

HEAT EXCHANGER/COLD PLATE

PROVE MANUFACTURING TECHNIQUES FOR LARGE PLATES. REVIEW TECHNOLOGY FOR

GREATER COMPACTNESS, LOWER WEIGHT. ADAPT TO FINAL SSF COOLANT SYSTEM.

73.
7

_ UNITED

TECHNOLOGIES

FINAL REPORT • IPTA--007-91

m

4.0 Conclusions and Recommendations

Recognized potential benefits of an SPE-Water Electrolysis based

hydrogen-oxygen propulsion system include a high thruster specific

impulse (Isp >400 SEC), high propellant mass fraction to orbit (>0.8), a

safe-to-handle fluid (HzO), and the ability to utilize waste water to

produce high performance propellant. The combined effect of these

benefits could produce a significant reduction in the life cycle cost of

large space platforms such as the NASA Space Station Freedom.

While offering these benefits, only limited testing of an integrated

electrolysis based H-O propulsion system had been conducted prior

to the initiation of the NASA/JSC IPTA program. The ongoing IPTA

testing is enhancing the SPE-Water Electrolysis knowledge and

experience base for future high pressure H-O propulsion and energy

storage applications.

SPE-Water Electrolysis for the production of hydrogen and oxygen

propellants is a developing technology. The heart of the process, the

high pressure SPE-cell stack, is highly developed. The IPTA Phase 1

test program has demonstrated the robustness of the SPE-Propulsion

Electrolyzer through nearly 900 hours of accumulated test time,

including test system problems and several environmental "act of

God" events. The basic cell stack design was and can again be readily

adapted to meet the Space Station or other mission goals.

The SPE-Propellant Generator system concepts show promise.

Several key technologies, most notably zero-G gas and water phase

separation, require development from low pressure or experimental

prototypes to fully reliable 3100 PSIA components. As future mission

goals are clearly identified, the development path for the accessory

package can be directed to meet those goals.

A development program to pursue the enabling technologies is

highly recommended. A development plan that identifies all

applicable missions, their goals and probability, and establishes .a

logical, evolutionary development path for the SPE-Propellant

Generator technology is needed.

w

= := 74.
_ UNITED

TECHNOLOGIES FINAL REPORT • IPTA-007-91

SOURCE DOCUMENTS

SPE-Propulsion Electrolyzer for NASA's Integrated Propulsion Test

Article, Volume 1, (contract proposal)

HSPC88T14

Statement of Work, Contract NAS 9-18030 (through Mod. 19)

SPE-Propulsion Electrolyzer Critical Design Review package,

IPTA-036-89

100 Hour Test Completion Summary Report,

IPTA-018-90

Operations and Maintenance Manual,

IPTA-033-90

SPE-Propellant Generator Conceptual System Design Review package,

IPTA 055-90

SOURCE DOCUMENT APPENDIX

PARTS LISTSAND DRAWINGS

COMPONENT DESCRIPTIONS

TEST DATA

COMPONENT CONCEPT DESCRIPTIONS
UNITED

TECHNOLOGIES FINAL REPORT . IPTA-007-91

SOURCE DOCUMENT APPENDIX

SOURCE DOCUMENT APPENDIX

v

r

CELL STACK DRAWINGS LIST

TEST FIXTURE PARTS LISTS AND DRAWINGS

[]

=--

==
UNITED

TECHNOLOGIES

IPTA CELL STA(_K DRAWINGS

FINAL REPORT • IPTA-007-91

SOURCE DOCUMENT APPENDIX

(_QNTRACT NA_; 9-18030

CELL SUBASSEMBLIES & PARTS

Divider, Oxygen

VOLTAGE TAB

OXYGEN DIVIDER

Assembly

GASKET, 02

DIVIDER, OXYGEN

02 Frame and Screen Assembly

OXYGEN FRAME

PROTECTOR RING (Niobium)

OXYGEN SCREEN

H2 Frame and Screen Assembly

HYDROGEN FRAME

PROTECTOR RING (Polysulfone)

Screen and Fret Sheet Assembly

FRET SHEET

H2 SCREEN

GASKET, H2

Hydrogen Divider and Rings

HYDROGEN DIVIDER

Fret Sheet and Ring Assembly

FRET SHEET

PROTECTOR RING (Mylar)

Pressure Pad Assembly

PRESSURE PAD

PRESSURE PAD STRIP

PRESSURE PAD STRIP

Screen and Ring Pad

PROTECTOR RING (Mylar)

PAD SCREEN

M & E ASSEMBLY

GASKET, MANIFOLD

GASKET, MANIFOLD

IPTA SVSK#

SVSK117701-1

SVSK117703-1

SVSK117702-1

SVSK117704-1

SVSK1 17702-1

SVSK117705-1

SVSK117706-1

SVSK117707-1

SVSK117708-1

SVSK1 1771 1 -1

SVSK117713-2

SVSK117707-2

SVSK117712-1

SVSK117714-1

SVSK117715-1

SVSK1 1771 6-1

SVSK117717-1

SVSK117718-1

SVSK117719-1

SVSK117722-1

SVSKI 17707-3

SVSKI 17720-1

SVSK117724-1

SVSK117725-1

SVSK117725-2

SVSK117721-1

SVSKI 17707-3

SVSK117726-1

SVSK1 1 7709-1

SVSK115596-1

SVSK115596-2

w
w

w

u

0

Z

415 / .,_1 4--.,-,.

_< 31"1 _

21S 4--.--,

213

v_

r;

,_:_ _>_, ,

,i,.

uu.,_

:,..,.o_,.

.<_,.

U.. ,

W _

_.,<

-ILl

"'I

£oo

I'-- =

0

).-

UJ
_Z

Ua .,a' .,._ Z ,,.a

._J___o LU UJ _a UJ

_ 0,. 0 _ u. (.3

UJ

C_

/-. x_O

-LU

w_.l

.<

14J

C3 -

C/3

cd3 =

Cr_

=

_U4ud

_a

w
MAJOR PARTS LIST

_ITEM NAME

MAJOR PARTS LIST

TEST FIXTURE SCHEMATIC SVSK 116070 L

P/N l SUPPLIER t MATERIAL T, PRESSURE

/

TEST FIXTURE SCHEMA TIC SVSK 1 18070

WETTED I

P/N MA"

MODULE

CURRENT SENSOR

_SOR

TEMPERATURE_ SENSOR

TEMPERA'RJRE SENSOR

GP'204

CELL STACK

DATA AQ. AND CONTROL

HAMILTON STANDARD REF DWG

!NSEN

EMPRO

MODEL 580 MSA

_;01-T

OMEGA

C01-T OMEGA

SORENSEN

SVSK117505 HAMILTON STANDARD INCONEL 718

19D HEWLETT PACKARD

PNEU. ACTUATOR VALVE 8380A2 ASCO ALUMINUM, VITON I 80 N2

L VALVE V47-AB-2 _ PENN BRASS

PARATOR SVSK117764 t HAMILTON STANDARD INC 718 VITON A 3100

LEVEL SENSOR 4G2536 TEDECO 3100

ICIRC PUMP M.H.Q_EL 220 MICROPUMP 31 (30

It

m

FLOW TRANSDUCER

BACK PRESS. REG.

FPNEU. N.C.

HX I ! I IH AT EXCHANGER

CV 220 I CHECK VALVE

T ! I ! MP RATURES N OR

HPS 300 1 IHYD. PHASE SEP. HI. PRESS.

LS 3o_I, !L_EVEL SENSOR

AOV 302_ _ .'PNEU. VALVE NO.

AOV 304t _ TPNEU. VALVE N.C. --

3061 2 _DIFFBACKPRESS mEG.

2 IPRESSURE TRANSDUCER

F 309 3 IFILTER

_DIFFBACK PRESS. REG.

A 317 JC MB. GA S NSOR

HPS 3_E SEP. LOW PRESS.

S 3 2 4 ! VE SWITCH

RV 3231 1 tRELIEFVALVE

RV 324i 1 RE IEFVA V

RV 325 I tRELIEFVALVE

A V 3 7 1 PN U. VALVE NC.

CV 321_1 1 ICHECKVALVE

V 330 1 MANUA VALV

SP711-1 lO-L_._L._L SPONSLER INC718, "I"FE 3100

29058 ___ 3100

1006-K-INC INCONEL 718 _ 3100

r 3100

269-4 76G .L TESCOM 31 CO

LEE MONEL

SS-HBVS4-C WHITEY 3165S 31 00

WHn'_ 316S_ 3100

SS-HBVS4.-C wHrrE_Y. 3t6SS VESPEL 3100

HTC-(NM-,4C- 1,_

COI-T

NUPRO

PARKF_._._

NUPRO...._

-- OM GA

OMEGA

316SS vIT N

INC VITON A I 3_00

INCONEL 600 t 3't00

MONE VITON A F 31 00

.L

t

SVSR 117750 HAM ILTON STANDARD

4G2535 TEDECO

SS-HBVS4-O

SS-HBS4-C

JETX05241 00B R..L.R__.ev_A_J

316L. 316 vrroN A I 3000

3000

316SS_ VESPEL FLEECO

WHrFEY 3000

wHrrEY 316SS, KEL-F } 3000

316SS T 3000

TESCOM

269-474(3iF:r1 " I

269-.475G

316SS KEL-F T 3000

lO06-K-A286 PAROSCIENTIFIC A-286 J_ 3000

AMETEK 316SS / 15

SS-4FW- 15 NUPRO 3000

JETX0524000B RevA

SS-HBVS4-C

4741 Modi6

SV SK 117736

SS-4CA-50

TESCOM

LEE CO

wHrrEy

USA

HAMILTON STANDARD

TE EC

NUPRO

NUPRO

NUPRO

H Y

NUPRO

JPRO

NUPRO

SS-4C-1

SS-H V C

SS-4C- I/3

S S-4P4T

SS-4P4T

316SS ]

316SS KEL.F 1" 30OO

316SS i 3000

316 SS V.,._.y_ESPEL i

POLYCARBONATE TFE I

3000

10

316L 316 VII'ON A 1 3000

316SS VITON A I 10

316SS. vITON A I 3

316SS VITON A 1

16SS VESP _0

316SS. VITON A I 10

I... 3 6_ _0

__°

w

Page t

w
w

!MAJOR PARTS LIST

,. r

ITEM NO. QN.T ITEM NAME

DPR 400I 1 IDIFF. PRESS REDUCER

' RV 401I 1 RELIEFV'ALV E

I P_ 402' 1'" !PRESSURE REDUCER

sv 4o3! 1 tSOLVALVE,N.C.

PT 404( 1 iPRESS. TRAN,SOUCER

F _s,! 1 ]FIt.'rER

DBPR 406 1 iDIFF. BACK. PRESS. REGULATOF

OR 407 ! fORIFICE '

F 408 1 FII_TER

SV 409 1 SOL VALVE, N.C

, OR 410 1 O.RIFICE

OR 412 I IORIFICE

R_ 413 1 tRELIEFVALV E

AOV 4151 1 iPNEU. VALVE, N.0.

C..V. 4161 1 ICHECKVALV E

OR 417i 1 IORIFICE

AOV 41e! 1 !PNEU _VALVE, N.C.

CV 419! I _CHECKVALVE

OR 420! I IORIFICE

OB 421] _ PORIFICE

T i

F; 500{ I iWATER FEE[)'PUMP

sv _7

TEST FIXTURE SCHEMATIC SVSK 116070

wETrE0 i

PfN SUPPLIER

269-477G TESCOM

MATERIAL I PRESSURE

316SS, KEL-F I

SS:4RCA-350 NUPRO .316SS, VITON A I

44-1125-2.4 I TESCOM 31,6SS, KEL-F J .

MV100 MAROTrA CRES300 , VESPEL, VITON AI

1006-K-INC PAROSCIE NTIFIC ..... INCONEL 718 ..

SS-4FW- 15 NUPRO, . 31.6SS

269--471_.. TESCOM .316SS , KE_-F

J,E,HA 1875350L ,LEE co 304 L ss

s.._4FW- !5 _ NUPRO .316SS

MVIO0 1 MAROTI"A CRES300, VESPEL, VITON A

JEHA1875350L LE.E CO 304L SS

JEHA1875350L . LEE- CO 304 L SS

S._P4CA.350 NUPRQ 316_S, VITON A

SS-HBVS4-O WHITEY 316SS, VESPEL

SS-4C-i/3 ( NUPRO 316SS, V1TON A

JETA1875170D ! LEE C,O 304L SS

SS-HBVS4-C I., WHITEY 31SSS, VESPEL

SS-4C-1,'3 L .NU.pRO, 316SS, VITON A

VOCX0513600B, R.ey.A I LEE C.O. _04L SS

JEHA187_..50L LEE CO 316SS

MB1-A13-PQ71 J .M.!LTON ROY 316SS, TFE, CERAMIC

MCY4463H025 PAU, POI, YPROPYI.E NE3250

3250

5000

32OO

3150

315o

3150

3150

3150

3150

3150

3150

3150

3150

3150

3150

3150

3150

3100

10

10

1o

lo

5021 I iTHREE-WAY ,._OLVALVE

50_i,I IW,A_RR_S,_;T_vrrY SENSOR

IDEIONIZER COLUMN

I !SOL VALVE, N. C.

508! 1 iPNEU VALVE, NC.

CV! .50gJ 1 !CHECKVALV E

203.3414-21-5

8.74RS-AT

_._ .510 i 1 IRELEF VALV E

511! I IFLOW TRANSDUCER

GALTEK PFA CrFEI

FOXBORO TITANIUM, 316ss

HAMILTON STAND.ARD RESIN, POLYCARBONATE i

203-1414-21-5 GALTEK PFA ITFE) j ' 10 ...

SS-HBVSa.-C WHITEY 316SS, VESPEL I 10 ..

H-4C-1/3 NUPRO HASTELLOY C _ [ 3100

.SS-4RCA-3,50 NUPR o 316SS, VITON A j 3200_

MF-30 . SPONSLER INC718, .TFE J 3100

w

r

w

L

Page 2
=

: iwLw

p%

o

c,0

if') r.D .<

<iloII \

++.=<°

C')

x(D_

u_<:_ _-

.uO

<-00d O-J

__m co

__a CO

w< O-b _.-

Lu@_ ''- _''

<LU>_

b-- _.J -;

_-LLI CO°

Ix.

ZG <7,

o_

_--il.l __,_o

z-J<_-S

=l"- _i"l#l :__ N -m r _
m

p

w

w

m

"°r

;J.

O.

:IZ

0

_J

09

Z _

o -- o

0

_ Z

LU

(n

_v

¢on-n

Zo

Oo

0

e.

×_

_<_

culf_ "_

<

_0

__ r..o =o

,,,_., :.._ cz E

r-.z.r-z

w
_ UNITED

TECHNOLOGIES

I_&1_11%_@1_

SOURCE DOCUMENT

FINAL REPORT • IPTA 007-91

SOURCE DOCUMENT APPENDIX

APPENDIX

Tp_,.-

COMPONENT DESCRIPTIONS

i

--J

w

w

m

=

m
",..j

_--t

m

w

f

_ UNITED

TECHNOLOGIES

IX]AI_flILY@_

FINAL REPORT " IPTA-007-91

SOURCE DOCUMENT APPENDIX

Major Components Descriptions, Special Test Fixture

Major fluid components in the system are described by class in the following

sections.

Pressure Transducers/ Transmitters

Pressures of the oxygen and hydrogen produced, the nitrogen reference gas

and the differential pressure between nitrogen and each product gas are

needed for process control and fault detection. For 3000 + PSI measurements, a

high accuracy absolute pressure transmitter with a range capability of 0 to 6000

PSIA, an accuracy of +0.01% and a 5x10 -8 resolution was selected

(Paroscientific model 1006-K). These devices are temperature compensated

and communicate with the process controller via a RS-232 bi-directional "daisychain" two-wire loop. The test fixture pressure transmitters are designated

PT207-x (two required) for oxygen; PT307-x (two required) for hydrogen; and

PT404 for nitrogen. The process controller computes differential pressures

using the respective absolute pressure transmitter readings. Material wetted by

the gases are Inconel for oxygen and A286 and 316 stainless steel for

hydrogen. The standard Inconel material is used on nitrogen service.

Excitation voltage to the transmitters is 15 VDC.

A 60 PSIG strain gauge type pressure transducer is used to measure hydrogen

pressure in the low pressure hydrogen water recovery circuit. Protonic water is

reduced in pressure in a phase separator to release dissolved hydrogen. This

sensor, designated PT308, is located on the vent output of the low pressure

phase separator HPS318. Wetted materials are 316SS. (Ametek p/n IPT)

Pressure Reaulators

The role of ba(:k pressure regulators DBPR 210, 310 and 406 is to maintain a

pressure differential between the gases at any operating pressure within

minimum hardware.

Safe operation requires that nitrogen pressure dominates that of oxygen, which

in turn exceeds that of hydrogen. This scheme will always allow for a total

system nitrogen flush-down.

To keep a balance between inside and outside cell stack pressure, a dome

sensed reducing regulator, DPR 400, will control the nitrogen pressure to the

cell stack dome as referenced by the oxygen produced. A manually set positive

bias insures the pressures to be nitrogen over oxygen.

In a similar way, when the cell stack is depressurized, oxygen sensed dome

regulator DBPR 406 will vent the cell stack external pressure so that the

nitrogen pressure is favored over the oxygen as set by a positive bias. Although

the oxygen production is the control factor in the cell stack operating pressures,

hydrogen pressure is also controlled by negative bias, back pressure regulator

DBPR 310. The dome pressure of this regulator is nitrogen sensed instead of

oxygen for safety reasons. The differential between nitrogen and hydrogen will

be sufficiently larger throughout the working range so that oxygen pressure will
w

m

G

= ......

UNITED

TECHNOLOGIES

I_&MI]l_fiZ@l_ FINAL REPORT • IPTA-007-9 l

SOURCE DOCUMENT APPENDIX

be maintained over that of hydrogen. Control bands for the regulators require

regulation to +9 PSI at any pressure. Refer to Operations Manual,

Appendix D for the pressure set on each regulator.

In addition, two regulators, DBPR 306-1 and -2, reduce the water/hydrogen

pressure for the low pressure separator. The upstream regulator, -2, is

referenced to the system nitrogen to reduce pressure downstream. The

downstream regulator, -1, maintains a constant pressure for the -2 regulator,

assisting in the control of pressure reduction from 3000 PSlA to 20 - 50 PSIA.

Wetted materials in contact with oxygen include Inconel 600/X750, Elgiloy,

Haynes 188 and Vespel SP21, Teflon soft goods. Wetted materials in contact

with hydrogen and nitrogen include 316 stainless steel and KeI-F, Teflon soft

goods.

Regulator setting records are included in Operations Manual, Appendix D.

Feed Water Pumo (FP 500_

Electrolysis feed water and pressure-reduced protonic water at near-ambient

pressure is pressurized to 3100 PSIA and injected into the oxygen side water

recirculation loop with a positive displacement pump, part of a pump package

(Figure 2-9a). The pump is a Milton Roy Model MB1-A13-P071, packed

plunger liquid end, totally enclosed self-lubricating, controlled volume, with

double ball checks. The stroke length is adjustable from 0-100% capacity while

the pump is in operation. Capacity adjustment is done through an electronically

controlled actuator. The plunger is 7/16 ceramic and at 113 SPM delivers 4.8

GPH at 3200 PSIG. The plunger is sealed with replaceable Teflon rope packing.

The ball checks are ceramic with carbide seats.

Power rating of the pump motor is 1 HP; the electric power supply is three

phase 240 VDC. A pulsation damper ( LDI Model PH 4.5 - 5000P - D 4.5 ) is

connected immediately after the pump discharge and removes 90% of the

pulses in the pressure range of 2500 to 3200 PSIG. The damper is made of 316

stainless steel and has a Viton diaphragm. The diaphragm is inflated with

gaseous nitrogen through a valve adapter to 80% of the operating pressure.

Water Circulating PumD (GP 204_

Water is circulated through the oxygen side (anode) compartments of the

electrolysis cell stack in order to provide electrolysis feed water and to remove

product oxygen and heat. This oxygen side water is circulated by a high case

pressure gear pump. A special version of the Micropump Model 220 gear pump

was made so that the case will withstand 3000 operating pressure with an

input/output differential pressure of 30 PSI. Materials in contact with feed water

and entrained/dissolved oxygen include Ryton gears, Inconel pump case, and a

tantalum shroud around the drive magnet sealed by a Viton "O"-ring. The Ryton

gears are replaceable.

The pump motor is operated and controlled from a 24 VDC power supply which

provides delivery of feed water from 2500 to 6200 ml/min, depending on the
w

7

w

==

m

w

W

L

UNITED

TECHNOLOGIES

voltage and current selected.

or off as required.

FINAL REPORT • IPTA-007-91

SOURCE DOCUMENT APPENDIX

The process controller turns the power supply on

Flow Transducers (FT 205, FT 511)

The water circulation flow rate through the cell stack is measured with an in-line

Sponsler turbine flowmeter, Model MF 175. The flowmeter has a range of 300

to 11,355 cc/min at 3000 PSIA pressure. Flow reading is obtained from the

magnetic rotor by a modulating coil. The output signal of the transducer is then

fed into a signal conditioner, where it is amplified and linearized. The output of

the signal conditioner is a 0-5 VDC signal that is proportional to flow rate. Due

to the dissolved oxygen in the water, the wetted components of the transducer

are Inconel and TFE.

At the time of shipment, FT 511 sensor was not active. (The signal has been tied

to ground.)

Valves

A mixture of electric solenoid (SV) and air-operated (AOV) actuated valves are

used in the test fixture. The following table lists all process valves in the system

according to valve type, unpowered position, system operating pressure,

working fluid and major materials of construction.

PROCESS VALVES

VALVE # OP PRESS FLUID MATERIALS

AOV 213

AOV 215

AOV 216

AOV 3O2

AOV 304

AOV 313

AOV 327

SV 403

SV 409

AOV 415

AOV 418

SV 502

SV 507

AOV 508

POS

nc

no

nc

no

nc

nc

nc

nc

RC

no

nc

3-WAY_

nc

nc

3100 PSIA OXYGEN

3100 PSIA OXYGEN

3100 PSIA OXYGEN

3000 PSIA HYDROGEN

3000 PSIA HYD./WATER

3000 PSIA HYDROGEN

3000 PSIA HYDROGEN

3200 PSIA NFFROGEN

3150 PSIA NITROGEN

3150 PSIA

3150 PSIA

NIT./HYD.

NIT._XYGEN

316SS_ Vespel

316SS, Vespel

316SS, Vespel

316SS TVespel

316SS_ KEL-F

316SS, Vespel

316SS, Vespel

ALUM, SS, Nylon

ALUM, SS, Nylon

316SS, Vespei

25 PSIA WATER

25 PSIA WATER PFA, Kalrez

25 PSIA WATER 316SS, Kalrez

316SS_ Vespel

PFA, Kalrez

Pneumatic Valves (AOV-xxx)

The pneumatically-actuated process valves used for all H2 and 02 service

(Nupro p/n HBVS4-x) consist of a valve body coupled to a pneumatic actuator

which is isolated from the wetted area of the valve by a high pressure design

bellows and diaphragm assembly. The pneumatic actuator has a spring to

return the valve to its normal open or close configuration ( Normally open is

designated by a "-O" suffix to the part number; normally closed by a "-C" suffix ).

A vent hole between the valve body and the valve operator prevents pressure

build-up should a leak occur in the bellows/diaphragm assembly. The valve

body, seat and stem are rated at 3500 PSI. Material in contact with process

i
: _

=

W

w

m

m

_ UNITED

TECHNOLOGIES FINAL REPORT . IIYTA--007-91

SOURCE DOCUMENT APPENDIX

fluids is 316 stainless steel; the valve stem has a soft seat insert made of

Vespel (AOV304 has a KeI-F insert, p/n HBS4-C).

The pneumatic valves are actuated using 75 PSi nitrogen applied by remote,

dedicated pilot valves (designated as SV112-x, manufactured by Asco as p/n

8380A2 ) These 3-way valves vent the AOV actuator pressure when

deactivated, returning the AOV to its normal open or closed position.

Respective pilot valve/AOV pairs are indicated on the system fluid schematic

SVSK116070

Solenoid Valves (SV403. SV409_

The Marotta solenoid valves, Model MV100A, are 2-way, 2-position electric

valves requiring 24 VDC, 1.0 amps. The valve operates at pressures from 0 to

3200 PSIG by actuating a poppet connected to the armature through a seal;

poppet return is by a spring. The valve features a balanced pressure poppet

design, assuring positive shutoff at full pressure. Wetted material includes a

forged CRES body, 304SS poppet, and Vespel seat.

Solenoid Operated Diaphragm Valve (SV 507)

This valve admits low pressure feed water to the system, making up for that

water which is converted to product gases. Wetted parts in this solenoidactuated valve are PFA/'reflon except for the Kalrez poppet seal. The valve

operating pressure range is limited from atmospheric to 70 PSIG; operating fluid

temperature range is 0 to 100 °F. The valve is actuated by 24 VDC and draws

0.5 amperes. The wetted area and electrical components are isolated from

each other by a PFA diaphragm.

Three-way Valve (SV 502)

A three-way valve in the pump package is used to divert low resistance process

water (<1 M_) away from the feed pump inlet to a waste drain during PREPARE

mode. Normal unpowered position of the valve rejects water via a drain port in

the pump package. When the water is at or above 1 M_, the three-way valve is

actuated, admitting the water to the high pressure pump inlet. Materials used in

the valve are similar to diaphragm valve SV507.

SeDarators. H2 (HPS 300, HPS 318)

Gas/water separators were designed and built to separate hydrogen gas and

protonically pumped water in the cell stack hydrogen outlet stream. The high

pressure separator (HPS300) receives hydrogen and water directly from the

cell stack at 3000 PSI and separates the hydrogen from the water through

impingement of the incoming two-phase stream on a baffle and by swirling

action inside the separator body. Water collects in the bottom half of the

separator due to gravity. High pressure hydrogen exits the top of the separator,

passing through a screen to trap fine aerosol mist. Water exits through a screen

in the base of the separator; the screen holds back most entrained gas bubbles.

Water from the high pressure separator is saturated with dissolved hydrogen

gas at the operating pressure of 3000 PSIA. This dissolved gas must be
!

_ UNITED

TECHNOLOGIES

SYA_SDA_@

FINAL REPORT • IPTA-007-91

SOURCE DOCUMENT APPENDIX

removed prior to injecting the water into the oxygen side water recirculation

loop via the feed pump. "De-gassing" of the protonic water is accomplished by

pressure reduction and a second gravity phase separation stage. The

water/dissolved gas stream passes through a pressure reduction stage

consisting of two back-pressure regulators, a flow restrictor and a shut-off valve.

The valve is controlled by level sensors in the primary phase separator

HPS300, preventing this separator from draining completely and passing gas

into the second stage. In the second separator (HPS 318), hydrogen escapes

from the water due to reduced pressure (0 to 15 PSIA) and is vented to the low

pressure outlet of the test rig. The water is collected at the bottom of the low

pressure separator. Protonic water is recycled until a need for make-up feed

water is sensed. Level sensors mounted in HPS318 detect the quantity of

accumulated protonic water available and direct the controller to keep water

supply valve SV507 closed until a low level is reached, indicating the need for

make-up water.

Separator, 02 (OPS 200)

The high pressure oxygen/water separator receives oxygen and water directly

from the cell stack outlet at 3100 PSI and separates them by impingement and

by a swirling action induced by the tangential inlet. The high pressure oxygen

escapes through the separator top, passing through a de-mister screen. Most

entrained gas bubbles in the water are removed by a screen as the water flows

through the bottom of the separator and exits to the circulation pump (GP204)

downstream.

Water Level Sensors (LS201-x. LS301-X, ,LS322-x)

Four sensors are mounted vertically in each phase separator column to detect

and control water level. The top level sensor (designated LSxxx-4) provides a

high water level alarm. The water level is controlled between the middle two

level sensors (designated LSxxx-3 and LSxxx-2 ). A low level alarm is

provided by the bottom level sensor (designated LSxxx-1).

As-shi.o.Ded level sensors. The sensors supplied at the time of shipment sense

the presence of water by optical means. An arrangement consisting of a

borosilicate glass prism, a photodiode and a photosensor detect the change in

refraction at the exposed conical end of the prism when wetted by water. On

board sensor circuitry provides a digital signal to the controller. The sensor

housings are made of Inconel 718 for oxygen; 316SS for hydrogen. The

sensors are model 4G2536 for oxygen service and 4G2535 for hydrogen

service, manufactured by Vickers/TEDECO.

Alternate level sensors. In response to operational instability of the high level

optical level sensors in the oxygen phase separator (LS201-4 and LS201-3

positions) , an alternate level sensor based on sensing low voltage AC

electrical conductivity was developed by Hamilton Standard. Subsequent

modifications by NASA led to replacement of all high pressure sensors with low

voltage AC conductivity sensors. Diagrams and description of the sensor are

included in Operations Manual, Appendix E.
UNITED

TECHNOLOGIES FINAL REPORT • IPTA-007-91

SOURCE DOCUMENT APPENDIX

Heat Exchanger (HX 219)

Heat generated as a byproduct of the water electrolysis reaction is removed

from the cell stack by the process water recirculation flow. This heat is

subsequently removed from the process water stream through a dual heat

transfer coil type heat exchanger (Parker DHTC-IN-6). The Inconel center tube

conducts the process water through the heat exchanger while the surrounding

copper tube allows the coolant to counter flow. A flow control valve (TV113) on

the coolant inlet meters the coolant flow required to maintain a controlled

process water temperature between 100 and 130°F. The valve is actuated by a

freon sensor bulb in thermal contact with the water outlet tube from the oxygen

separator. Inlet and outlet thermocouples monitor coolant temperature.

t, ,4

mm
_ UNITED

TECHNOLOGIES

SOURCE DOCUMENT

FINAL REPORT . 1PTA-007-91

SOURCE DOCUMENT APPENDIX

APPENDIX

CELL STACK, TEST FIXTURE TEST DATA
DD E' x k . v • i

)_<

v

<00

c_0

O_

¢- 0

(DE0

O_ oo

cov

Q. 00

0,1

O4

Ckl

_D

,°
= :

p==z

Zw_

N

(.3 (_ --DO .

_o

O-T-

,,, (J_

._ e-"

m 0

_,.

"Z

_o

_-CL

oF--

_gn

¢.D -_-
W cxi

O0

0- ,i,--

WO)

_z

F..-_ m

0

_o

_,.

"Z

_oQ

\

\

_ "-"--.

-\
7

---,..

i....,

m..__.__

N

Z _

-J

_0

o-CO

O0

_CO

I.u

hncox

LU

¢C t--

0

_=__

o_Q.

(,5"T--

-_ CC

c_ C_

.d _ _ _ o

c_ LTj

0

 ̧

ut _ ,._

0 o")

b_

° _'.,.I

= i_ :>_ 0

--," _ -_ CO

U o3 E

r_ "_ "-'

0 0 _

,--, I_ Cr_ U _ .,_, 0

_ 0 "0 0 _ "_

o_ _f_ o

r._ 0 _ _ 0 _ _ 0

I I l

I'-. 0 cO

',- _ 04

l I I

0 0 0 0 0

0% 0% 0% 0% 0%

l l I I I

I I I I I
=

.

w

ILJ

---

IL

--7

0

_-X
I

,,,,I

.,.,0.0,,_

m

¢.D

_g

0 _

p m

o

t-- <:_

w (D

Z _

_,.

oo

I_ -e,-

mO')

_z

F..._

_,.

"Z

o1--

Nm

ed'l "_r'-
w

w

b_

0 _

I-- O_

I--._

Z

0 •

_-O'J

O0

,

,,-<

u- Z

5o

o1---

a.
w

o__

¢0

--13..

0 °

_o

_.0'3

O0

a.._-

1,1.103

_z

k- "*"

ffl I--

_,.

"Z

_o

ol-.-

_g

x_

g

ffl

0

?_

if)

_ _._

_ E_ E,

.____ -- _

O_o._

_ag

E m

P.

! .

,_ o '-" _ o

__n

o _ .'-

o
2

b

•--.- Z

Z_

¢:

,,,az

i

,

I

!

Z

0

[,-,

Z

0

[-,_I

Z

,,,,_

= "5

9"_ o

e.__ _

o 0 "_

o ._ o"

o

8 o

t.0

o o 0 Ooc_ 0 o 0 o o ¢_ ,-- _ 0 o

Go

& & & &&& o_ & && !&&& & & &

ioJ

o o 0 0 0 0 0 0 0 0 0 0 0 0 0 0

B _B B B _B B_{_ B _ B

o

o

©
o

_ b

--Z

Z_

-- U3_

0 0

]

_z

Z

0

D-d

Z

.i

,.nl

Z

:.4

_ _ o .-_''_ --- 0. "" _"_ 0

, O_ "_ "_ r-4_

_,,,o._.,..1o_=,,,>,, ..,,.,,,,__,o o_o_=_>___, e_._

"_ ® o_ z

_-_ =_

, o® ;_o

_ _= _> ,.._ =-_. -_

_-o-- _.=_=_ __o x g ,_o=

oZ Z Zizo ,

r_,o tm

. z-' t-

- v- tSi_

_ _ 0077 7

__ > I_ -J v- v- v13 _.-- -J -J -J

_ _ _'_ E > > >

_ g

e...

_e_o r_ _oZ oZ _

_o__- o

Z_'_

o. O. c_ o. cl. I_ 13. 13. cu

o o o o o IO o o o

o o o <D <D I(D _D _D <D

0 ,"- _0 0 ",- 0 ',," 0

9--

I.o 14") to co

_o

i <_ i:[_

_ Io

o__

_o o

=== o.. , _-._

=-= _ _ ,--.-

c

,_o_ _,

o=o_'

0

z

o

t_

t_

co

&

O3

_J

60o4

--=

q)

0

z

._

°

_o__

_8===

_o

0

(13 q)

o£

o

o

e3

e3

o

(D

,,r==

o

e'3

o

p,...

',r--

C3

0

¢'3

0

04

,e..-

C4

,0
m

T

O

.<

r#.]

rJ3

O

_zl

o

I

_ j

ol

•<_ L I

,,=1

_q

2

g

_>,E

O 03

"oeo_o_

to

03o

'u., O

8._

0

N

-_ o" "-

_,_=

cO

_o o

LI,

_T.-O

>LL t" (f) O

• 0 = "--" = •

i

0

E 0 Z=

•--¢ o

,.. _ _._

÷.=_o=_._

_ _z_

"_ "_- ,._ o

o._-._ o0 - 00_ ¢/_ _

o ; _'o ¢_ _ _"

E

x

o

, -_

--_g

._._"

_ 0

_ R <

_ _> o

o

o

o

,6

tJ)

,o_ E

o-_ t-_

_>,_-_ ._

z.g .

- ¢._ .¢,.)

o

0'3

I_.

_._ --__ _='-EE - .-

_t-o o

2 8-6 _ _-. _._o_._.

__>

•_ _--E

o -_ Z ->'°

_>

o o

o o

03

o,I _1

"7 "7

0_3 O3

t.O t.D

os

Z

z"

0 .

0

0'3

"7,

O3

¢.-

0,1_ 0

__ _

_ e'-_

_- ==-

-o

c_

o

o

o3

"7

O3

aO

_ "_ o

o

•-- _ 0 _ o.._

z:_ _ _ _0._ Z ^

-= r ">.a-;,_

_,.,u ¢.,,.,..... _ "_ -r"_ _'_=- o-'S of...9_ _ ,, (---rr- ,_ o.)

_o ."=-(3...

"_ ==E O o3

z n'-N _.

o.

o

o

o3

"7,

O3

O3

0
r

,[.

i

Z

O0

_Z

_ 4

r_ Z

[.,,_

z"

g

ee3 o

03 o

(&. o.._

>=m_o

o'_-_

¢t)

t'-

z" _"

t_

d_
iO

i_,.d

I0_

_ J_

-- r_ ,r'T'l

_ [...,

,...1z

-- O0

rz.,l

Z !

-__ o i

- Z

- r_,

| i

!

o "_

,,.-.1.1...

._1 "" LI..

_o

i._ _Iz_ =_.E_"_

_oo ___..®_ z E I,... E__

_. ¢-I_ "_ 0 0 _2-0

o ,- _; _'_ "_ _" _ _"_'_

• • gO t,/_ _.

_._o

._=_-_

•"_"6 ,.. _

_=oo.£ o

_@-

>

,... o >_ £ ::::

,_.., _ "_ _,, ,.- _

E _,o= > oo o m

a ";" °m o _

"-'.._®_.- j_ &o. "_¢9 ,-,"-r_ _9

"T,

g-

_' ,..o

io=- "_o

§ o:..

"0> o

-__ n

"_- _o

"7, _ ,...._ "_

.,-.. -_ "-" t'_ _.)

0

Z

o o

o o

N ""

o

d_ m

(xl t_

o o o

o o o

.,- .,- _

_1 o,,I co

o o

o o

co co

¢,_ ¢,1

o,1 o

4. 4-

co

o

co

e0

i

¢0

e0
=

J

w

r

qm_

Z

i2

!<

P<0

,...1z

O0 I,,

==olI

<_ '-I Z

;=>:_1

,oooo

_c.3

5_E

_-o

c'o_

_c_o

_'__

'_" ._ < X" •_ <

ou-,>

e_ e_ o o

r--o | 4

',_ u')

o'1 ("3

o

oo

o_

_'.c (3

._._ "_ _ oe0

_ gg

--c _= _-_

__ .Bo

.,_ "_o ..c: 0,- o o

oE_-

-- C_O _u

co

o "_,

_n-,_

©

co
w

UNITED

TECHNOLOGIES FINAL REPORT . IPTA-007-91

SOURCE DOCUMENT APPENDIX

SOURCE DOCUMENT APPENDIX

SPE-PG CONCEPT SCHEMATICS, PARTS LISTS

SPE-PG COMPONENT CONCEPT DESCRIPTIONS

w

=

u
w

4

z._z

G_

w

i

z

__777-

!

ID

O.

! "_o_

0

I

I

0

_5_ j

e(.) _

2

,!!i!

'_El_i_l_i
=

,

%_.:

7_

_.7

=

w

SPE® PROPELLANT GENERATOR

CONCEPTUAL FLIGHT FLUID SCHEMATIC PARTS LIST

=TEM .NO.

EM 100

PWR 101

EIB 103

PWR 111

OPS 2OO T 201

HX 2O3 P 204 F 206

PT 207

RV 20e

OBPR 210

OR 211

2!2

SV 213

SV 214

SV 215

ACC 21S D 218

CV 220

DPT ,222

CV 223

HT 226

PT 227

PT 228

LS 229

BPR 230

RV 231

HPS 300

DPBR 301

RE 302 D 3O3 P 3O4

SV 3O6

PT 307

SV 310

OR 311

SV 313

_cc 314

RV 316

CV 317

SV 318

SV 319

RV 320

RV 322

0S 323

DPT 325

HT 327

PT 328

PT 329 T 33O

LS 334

CV 3.36

PT 337

DT 338

O1N" III1

2'" 1111213112111111111122111

MAJOR STRUCTURAL

REVF

11/28/90

OPERATING

PRESSURE

3loops!

N_

N_A

N_

ITEM NAME

CELL STACK, ELECTROLYSIS

POWER SUPPLY, STACK ,,,

INTERFACE BOX, ELECTRONIC

POWER SUPPLY, H2 STRIPPER

PHASE SEPARATOR, OXYGEN

TEMP. SI_ _SOR, STACK INLI_T

HEAT EX HEAT REJECTION

PUMP= RECIRCULATION"

FLOW TRANSDUCER, RECIRCULATIOH

FILTER I RECIRCULATION WATER, ,,

PRESSURE TRANS., STACK 02 EXIT

RELIEF VALVE, 02 VENT

MATERIAL

VARIOUS

VARIOUS

VARIOUS

VApK_Js

TBD

INCONEL718 .....

tNCONEL718

INCONE.L71S

INCONE_.711_

TBD

INCONEL71S

INCONEL718

3100p_i

3100p61

3100psi

3100psi

3100p#t

310opsi

310opsl

3100psi

DIFFERENTIAL BACK PF_ESSURE REG., 02 EXIT

ORIFICE,' 02 EXIT

TEMP. SENSOR, STACk' _XIT

S@LENO/D VALVE, 02 VENT

ISOLATION VALVE, 02 EXIT

SO(.ENOID VALVE, 02 VENT

ACCUMULATOR_ BUBBLE

DRIER, OXYGEN.

CHECK VALVE, 02 EXIT

DIFF. PRESSUR_ TRANS., O2 PHASE S_PARATOR

CHECK VALVE_ HEAT EX. INLET

HUMIDITY DETECTOR, O2 DRIER EXIT

PRESSURE TRANSDUCER, 0_ TANK

PRESSURE TRANS.f 02 RELIEF VALVE INLET

LEVEL SENSOR= BUBBLE ACCUMULATOR

PRESSURE RI_.GULATOR, OXYGEN

RELIEF VALVE, OXYGEN 0VERPR_SSURE

PHASE SEP/STRIPPER/$ENSOR ASSY, H2

PRESSURE RI_GULATORS, HYDROGEN

RECOMBINER

DRIER, HYDR',C_..'EN

PUMP, PROTON_C H20

SOLENOID VALVE, H2 VENT

PRESSURE TRANS.= STACK I_,,X,I,TH_

ISOLATION VALVE, H2 _,XIT

ORIFICE, H2 EXIT..

SOLENOII_ VALVE, H2 VE,NT

ACCUM,ULATOR, PROTONIC PUMP

RELIEF VALVE, H2 VENT

CHECK VALVE, H2 EXIT

ISOLATION VALVE_ PROTONIC H_ INLrET

ISOLATION VALVEt PROTONtC H20 PUMP EXIT

RELIEF VALVE, PROTONIC H.20 RCYCLE

KICKBACK RELIEF VALVE, PROTONIC PUMP

DOPPLER BUBBLE SENSOFI, H2

DIFF. PRESSURE T'RANSMITI'ER, H2 PHASE SEPARA.TOR

HUMIDITY DETECTOR, H;_DRIER EXIT

PRESS. TRANS._H2 RELIEF VAI_.VEINLET

PRESSURE TRA.NS.,H2 TANK ...

TEMPERATURE SENS., RECOMBINER

LEVEL S,ENSORj PROTONIC WATER ACCUMULATC_,

CHEC_ VAI_,VE,PROT. WATER ..MIXPOINT

INCONEL718

INCONEL718

lNCONEL71

!_.,ONE(.Z_ e

INCONEL718

INCONEL718

INCONEL718

INCONEL718

INCONEL718

INCONEL718

INCONEL718

TBD

INCONE_.71S

INCONEL718 ....

TBD

INCONI_L71_

INCONEL718

TBD

316L

A2e_

CRYOFORMED S.S.

316_,

3161.

31s_,

316L

, 3161_

316t,

31,6L

316L

TBD

TBD

316L

3_

316L

316L

"1"80

316L

316L

316L

31oopsl

31oopsi

3lOOps,I

31oopsl

310Opsl

31001361

3100pSi

310opsl

310opSl

310opsi

310opsi

310opsi

,, 310opsl

3100psl

310olosi

3100[_I

3_o0p6_

,_

3(_01_1

30cx_i

300o1_i

_oo1_1

30oomi

330o?si

3ooo1_1

_1

30oo1_i

30oo1_i

0o,0o_

3ooo_i

_1

_1

,3ooo_i

3ooo_i

_i

30oo_i

3ooo_

3o0o_i

PRESSURE TRANS, PROTONIC PUMP EXIT

TUBE, DWELL TIME 316L

30oopsl

3o0opsl

ACC

OR

SV

, PT

OR

SV

RV

LS

4001

4021

4031

4041

4081

4101

4151

4161

ACC ,UMULATOR, BOOT _TRAP

ORIFICE, N2 IINLET

SOLENOID VA[.V.E, N2 INLET ...

INCONEL718

3161.

3_

3150

3150

3150

PRE ,SS,URE TRANSDUCER, N;_

ORIFIC.E, N2 EXIT

SHUTOFFVALVE, N2 VENT

RELIEF .V.ALVE_N2 VENT

3_6L

3_s_

POSITION SENSORS' O_N2 ACCUMULATOR TBD

3150

3150

3150

3150

31.5_,

PF

CV

RV

RS

Ol

SV

ACC

CV

LS

5001

5021

5031

5051

5O61

5071

5081

5o92

5132

PUMP, FEED WATER

CARTRIDGE FILTER, FEEDWATER

CHECKVALVE, FEEDWATER ACCUMULATOR EXIT

KICKBACK RELIEFV.ALVE_FEEDPUMP

RESISTIVITY SENSOR, FEEDWA.TER

CLEAN UP BED, FEEDWATER

SHUTOFF VALVE, INLET WATER

ACCUMULATOR_ FEED WATER

CHECK VALVES, FEEDWATER

LEVEL SENSORS, FEED WATER ACCUMULATOR

3161.

TBD

TBD

TBD

TBD

TBD

mD

INCONEL718

TBD

TBD

3100

15

3100

3100

15

15

15

3100

3100

3100
i_m

__= Wm

,,+

oL

l-I

(13

k.

-p0

+(D

L -P 0 "'--

__ c-o ©E

gm© N 0 0 0 ""-

k_Q

® L)

I,I
4

r-- l

--=:

iiw

im

(%1 z

iiiii

on

)

0

rd

0

®

U.I

a.

I!1

=__

m

m

L

!

m

m

W
=

:

mzm l

bmmBl

IvI

_1I

i,,mi

v!

zo _A

•o

, o_o1

i.-

z<

o<o3

0 c__

0.. I

_¢.ov IL

_<

II _

UJ

OZQ

C_

"T,

,..J

c_

q, Q

c_

c_

c_

c_

lit
J

..-.,

III
,...,,

!,-

= z

w

w

=

_,._. 0

,..,_

m

A Ill

w

N

z

I

-,,/

_o_

,, !

,., i

°" i

•;- , b,

r,_ I \

O0 'LLk

o, .z '_I

._ x ,Fn,

w z ;co 7

'-,-' ,z", ,o

ug t-r'_ _,r,_" o( d':,

'ZD _-\ '

". -T (

m

I

4 _,=,, _<

z -I,: o z

,o: >.,,_

-T-,

v

I

o

0o

P_

aO

ug

L±]

0

I---

0

,G

..0.o<

_UJ_l _

_1'- :[:U)

-.J

-t..,,

q...,

®

Ill
=

_

n_nmuw

ffl
m

m0

zL

v

m

Rm

C_

C_

:30

t_

m

t_

:3

Q. U

t-OU

1,1,1 m

.-4

q)

q)

q.) E£

(I)

q3

q.) ®

III
m

m

@

m

vl

v

v.,=.-

ffl

_=,.,

,.O0<

_z_m

I-3:_Z

.---N 2__

_,,__ •

O0(_

®

Ill
wi

,_,.,...- rLL

0

aiDoi

m

v

I""

U.l 0

COZ

OC

I--

LU

OC

O0

O0

LU

n" non

m

_za

-lr-- _

_ _=_= • N I :

r.O

O>

LLI_I

-_.-'_ "-__I .'"

_';" ,I" ""

i,

/

_a

cJn

c_,l LIJ

I--'

r,,Q

CO

rr

UJZ

<_

rr

_0_ I--__ LJ_ L_. --J

a_E

L_®

lit
!,--

0

,¢,,,,,m

m

__'Sooooooooooooooooo_:=_---==-_-_

......._IILIZI,IIILIZ/_112 ........................... _-_=

_0_

w

L

• • • • •

L

E

q_

n_

£

®

Ill

° I_° 11
w

1

m

z_

in

(.I

®
= :

--Z

I,-,' I

OI

u.n

-o9,_

p=:z

Q

E

®
wi=.

o

w i -- i wmw | l I m ! im

or; 0

llm

m

m0Z

r_

F,,Q w

(DO(D

r"O "-

•.,-, (.0_

O9

OO c" OO

00m

-o.o m in o3

im

OZ.-_

,.,00<

c_

q)

b')

C_

(J

_)

(J

q_

q_®

o_ i
w

w

w

m

III

m

0

N

rn

m

u

_o

U) m

_E_

o_g

o_

_-N _.

u

m

_:1_®__o

c,,-d

o-_ _ -d

°

am _ m

e,,

• • • 0

I#I

W

n

_za

o_

,.,d

q

Ib

r_

q

q_

0

co

0

rg

®

tu

q..

w
L

.

wm=7 i"

_•

V I w B_I I L . w !

rtl ! 0

_z

c)

qo®

t_

III

w
w

w

w

v |

maw I

P_ a

_,01 I

A n

N i

w

i11

c_'_o ! [;;;; .-- LL

=_.___= . ._E _ o_.=o_

_-_ o •

_-_ l

=o_o,.

o_> ! "" +.,,(3) _..

_o . _.= (_._ _ _

O

_=E i

_-______ .. __ =_._.= o

._-_. a • 0 "" 0 •

_ _ '_u- I _) _= (/) __ .,._ | ,4,' _o_£,1 (_ (/] _ • 0 "_ O

___.(n__ 0

_-__! ,--= _ -_o _

a_ _- _ _! O_ 0

(/).4=-(3 _. _L _£o1 o "- •

,- "5o ,,, 0

o_o._i )< • 0 .,..r • ^

=_-_ ol o _ _,.o

__! '_ -" _ _-

_,.,= _ _ ! O_O

'-.'.,__-= _ _'t3) 0

_ t::: _ -" i

_1_ ("=") {"" ,,_ l _m lJ_-mE _!_

(-_mOl

I--__ •
ww

W

_jw

wn

I00

I

UJ

uJ ZlZ I

W

I

L) XWWI

III
!

w

w

v

m

0

N

v

r_m_ I

i-.

LLI

T

W

C_

nO

I--

rr'_

wo

Z

W

I[LII

/

m

_z_

_z_a

-.J

c_

c_

@

c_

c_

c_

c_

c_

®

cs')
_::= l! wAv

I'"e..-s

r.rJ

m

_z_qE®

a.