PT3E-0513

Explosion-Proof Calorimeter OHC-800

Sampling Device
RS-400 Series
Operating ManualPreface
Thank you for choosing our explosion-proof calorimeter OHC-800-RS-400.
This product is an explosion-proof calorimeter in a flame-proof enclosure (explosion-proof class: Ex
dIIB+H2 T4) consisting of a gas measuring part "OHC-800" and a sampling device "RS-400-□□□□," which
is designed for continuous, fast-response measurement of the "Calorific value," "Density," and "WOBBE
index" of various fuel gases such as natural gas, coke oven gas, blast furnace gas, converter gas, biomass
gas and biogas.
This manual describes how to use the calorimeter. Not only the first-time users but also the user who havealready used the calorimeter must read and understand the operating manual before using this product.
This manual mainly provides descriptions on the sampling device. Read also the separate volume "OHC800 Operating Manual" for the operation of measuring part OHC-800.
Throughout this manual, the following indications are used to ensure safe and effective work.

DANGER

This message indicates that improper handling may cause death or serious
damage on life, health or assets.

WARNING

This message indicates that improper handling may cause serious damage on
health or assets.

CAUTION

This message indicates that improper handling may cause minor damage on
health or assets.

NOTE

This message indicates advice on handling.

<Contents>
1.
1-1.
1-2.
1-3.

Product Overview .................................................................................................... 2
Product components and accessories ..................................................................... 2
Names and functions for each part .......................................................................... 3
Outline drawing and tubing diagram for each specification ..................................... 4

2.
2-1.
2-2.
2-3.

How to Install Calorimeter ....................................................................................... 15
Precautions on installation site ................................................................................ 15
Precautions on installation....................................................................................... 16
Maintenance space ................................................................................................. 17

3.
3-1.
3-2.
3-3.
3-4.
3-5.

How to Connect Wire............................................................................................... 18
Description of terminal plate .................................................................................... 18
Recommended cable............................................................................................... 20
Cable connection ..................................................................................................... 21
Protective grounding ............................................................................................... 23
Precautions on electrical work ................................................................................. 24

4.
4-1.
4-2.

How to Tube ............................................................................................................ 27
Recommended external tubing system ................................................................... 27
Precautions on tubing work ..................................................................................... 29

5.
5-1.
5-2.
5-3.
5-3-1
5-3-2
5-3-3
5-3-4
5-4.
5-5.
5-6.

How to Adjust/Use Calorimeter ................................................................................ 30
How to start the gas detector................................................................................... 30
How to use three-way switching valve ..................................................................... 32
How to use sampling parts ...................................................................................... 35
Adjusting needle valve............................................................................................. 35
Adjusting pressure reducing valve ........................................................................... 36
Bypass line .............................................................................................................. 377
Relief valve .............................................................................................................. 388
How to adjust reference gas flow rate ..................................................................... 399
How to adjust measuring gas flow rate .................................................................... 40
How to adjust calibration (standard) gas flow rate ................................................... 411

6.
6-1.
6-2.

Maintenance ............................................................................................................ 422
Maintenance item .................................................................................................... 422
Procedures to store the calorimeter or leave it for a long time ................................ 422

7.

Definition of Terms ................................................................................................... 433

8.
8-1.

Product Specifications ............................................................................................. 444
Product Specifications ............................................................................................. 444

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1 Product Overview

1-1. Product components and accessories

1

Product Overview
1-1. Product components and accessoriesGas measuring part "OHC-800": 1 set
Sampling device "RS-400-□□□□": any set* See the following classification of sampling device models.
Operating manuals (this manual and the operating manual for measuring part)

NOTE
This product is designed to have a measuring part "OHC-800" incorporated in the sampling device. The
tubing required for "OHC-800" has been arranged inside the main unit prior to shipment.
[Sampling Device Classification]

RS-400-□□□□
Storage box
0: No storage box
1: Outdoor box (SUS) with shading plate
2: Indoor box (SPCC) with window

Use of pressure reducing valve for measuring gas
0: Pressure reducing valve not used
1: Pressure reducing valve used

Bypass flow rate of measuring gas
0: Not bypassed
1: 0.5 - 5 L/min
2: 1 - 10 L/min
3: 2 - 20 L/min* "0: Selection unavailable" is applied for the casewithout pressure reducing valve.

Pressure gauge unit
1: MPa2: MPa/PSI double units* "1: MPa" is selected for the use in Japanbecause of the Measurement Act.
2 / 45

1 Product Overview

1-2. Names and functions for each part1-2. Names and functions for each part
The following figure shows a typical internal tubing system of the sampling device RS-400 series.

Unit names and functions
Unit
Symbol Part
UNIT-A V1
Needle valve
V2
Needle valve
UNIT-B

UNIT-C

UNIT-D

Functions
Adjusts the flow rate of the measuring gas supplied from UNIT-B.
Adjusts the flow rate of the reference gas or calibration gas
supplied from UNIT-C.
CV
Switching valve Selects a gas to be supplied to the OHC-800.
PR
Pressure
Adjusts the measuring gas supplied from GAS IN to a constant
reducing valvepressure.
PG
Pressure gauge Indicates the pressure of the measuring gas after pressureadjustment.
(Display scale: 0 - 0.2 MPa)FL
Flow meter with Adjusts and indicates the bypass flow rate of the gas discharged
needle valve
from BYPASS OUT.
(Display scale: 0.5 - 5 L/min, 1 - 10 L/min, 2 - 20 L/min* Varies by the specification.)PR
Pressure
Adjusts the reference gas supplied from REF IN to a constant
reducing valvepressure.
PG
Pressure gauge Indicates the pressure of the reference gas after pressureadjustment.
(Display scale: 0 - 0.2 MPa)V
Needle valve
Adjusts the flow rate of the reference gas to be supplied to the
OHC-800.
(Display scale: 0.5 - 5 L/min, 1 - 10 L/min, 2 - 20 L/min* Varies by the specification.)CV
Switching valve Switches the gas to be supplied to UNIT-A between the referencegas and calibration gas.
RV1
Relief valve
When the sampling system malfunctions, lets out an excessive
pressure from RELIEF OUT to prevent breakage of the OHC-800.
RV2
Relief valve* The UNIT-B specification without pressure reducing valve and bypass line is also available.
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1 Product Overview

1-3. Outline drawing and tubing diagram for each specification

1-3. Outline drawing and tubing diagram for eachspecification<RS-400-000□>
No storage box

Tubing diagram
Swagelok fittingfor 1/8" tube

Swagelok fittingfor 1/4" tube

Needle valve
Needle valve
Switching valve
Pressure reducing valve
Pressure gauge
Needle valve
Switching valve
Relief valve
Relief valve

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1 Product Overview

1-3. Outline drawing and tubing diagram for each specification<RS-400-00□□>
No storage box

Tubing diagram
Swagelok fittingfor 1/8" tube

Swagelok fittingfor 1/4" tube

Needle valve
Needle valve
Switching valve
Pressure gauge
Flow meter with needle valve
Pressure reducing valve
Pressure gauge
Needle valve
Switching valve
Relief valve
Relief valve

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1 Product Overview

1-3. Outline drawing and tubing diagram for each specification<RS-400-01□□>
No storage box

Tubing diagram
Swagelok fittingfor 1/8" tube

Swagelok fittingfor 1/4" tube

Needle valve
Needle valve
Switching valve
Pressure reducing valve
Pressure gauge
Flow meter with needle valve
Pressure reducing valve
Pressure gauge
Needle valve
Switching valve
Relief valve
Relief valve

6 / 45

1 Product Overview

1-3. Outline drawing and tubing diagram for each specification<Common between RS-400-100□, RS-400-10□□ and RS-400-11□□>
Outdoor box (SUS) with shading plate* Swagelok fitting for 1/4" tube is used at all connections of tubing.

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1 Product Overview

1-3. Outline drawing and tubing diagram for each specification<RS-400-100□>
Box internal drawing* See Page 7 for the outline drawing of outdoor box (SUS) with shading plate.

Tubing diagram* Swagelok fitting for 1/4" tube is used at allconnections of tubing.
Needle valve
Needle valve
Switching valve
Pressure reducing valve
Pressure gauge
Needle valve
Switching valve
Relief valve
Relief valve

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1 Product Overview

1-3. Outline drawing and tubing diagram for each specification<RS-400-10□□>
Box internal drawing* See Page 7 for the outline drawing of outdoor box (SUS) with shading plate.

Tubing diagram* Swagelok fitting for 1/4" tube is used at allconnections of tubing.
Needle valve
Needle valve
Switching valve
Pressure gauge
Flow meter with needle valve
Pressure reducing valve
Pressure gauge
Needle valve
Switching valve
Relief valve
Relief valve

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1 Product Overview

1-3. Outline drawing and tubing diagram for each specification<RS-400-11□□>
Box internal drawing* See Page 7 for the outline drawing of outdoor box (SUS) with shading plate.

* Swagelok fitting for 1/4" tube is used at allconnections of tubing.

Tubing diagram

Needle valve
Needle valve
Switching valve
Pressure reducing valve
Pressure gauge
Flow meter with needle valve
Pressure reducing valve
Pressure gauge
Needle valve
Switching valve
Relief valve
Relief valve

10 / 45

1 Product Overview

1-3. Outline drawing and tubing diagram for each specification<Common between RS-400-200□, RS-400-20□□ and RS-400-21□□>
Indoor box (SPCC) with window* Swagelok fitting for 1/4" tube is used at all connections of tubing.

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1 Product Overview

1-3. Outline drawing and tubing diagram for each specification<RS-400-200□>
Box internal drawing* See Page 11 for the outline drawing of indoor box (SPCC) with window.

Tubing diagram* Swagelok fitting for 1/4" tube is used at allconnections of tubing.
Needle valve
Needle valve
Switching valve
Pressure reducing valve
Pressure gauge
Needle valve
Switching valve
Relief valve
Relief valve

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1 Product Overview

1-3. Outline drawing and tubing diagram for each specification<RS-400-20□□>
Box internal drawing* See Page 11 for the outline drawing of indoor box (SPCC) with window.

Tubing diagram* Swagelok fitting for 1/4" tube is used at allconnections of tubing.
Needle valve
Needle valve
Switching valve
Pressure gauge
Flow meter with needle valve
Pressure reducing valve
Pressure gauge
Needle valve
Switching valve
Relief valve
Relief valve

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1 Product Overview

1-3. Outline drawing and tubing diagram for each specification<RS-400-21□□>
Box internal drawing* See Page 11 for the outline drawing of indoor box (SPCC) with window.

Tubing diagram* Swagelok fitting for 1/4" tube is used at allconnections of tubing.
Needle valve
Needle valve
Switching valve
Pressure reducing valve
Pressure gauge
Flow meter with needle valve
Pressure reducing valve
Pressure gauge
Needle valve
Switching valve
Relief valve
Relief valve

14 / 45

2 How to Install Calorimeter2-1. Precautions on installation site

2

How to Install Calorimeter2-1. Precautions on installation site
Do not install this product in any of the following locations.

(1) Place where the calorimeter is exposed
to oil, chemicals etc.

(2) Place with vibrations(3) Place where radio wave or noise isgenerated(4) Place where the calorimeter may dropor receive strong shock(5) Place exceeding the operating
temperature range
Place where the calorimeter is exposed
to direct sunlight or radiant heat

(6) Place where maintenance of thecalorimeter cannot be performed
Place where handling of thecalorimeter involves dangers

15 / 45

2 How to Install Calorimeter2-2. Precautions on installation

2-2. Precautions on installation
CAUTION
Do not drop or give strong shock to the calorimeter during installation.
Otherwise, the device may be damaged.

CAUTION
If the calorimeter is to be fixed on the wall, install it properly
where can hold its weight.

CAUTION
When installing the calorimeter on a freestanding rack (fixed type), fix the freestanding rack withanchor bolts.

CAUTION
When performing construction work, prevent dust from entering the inside of the calorimeter.

16 / 45

2 How to Install Calorimeter2-3. Maintenance space

2-3. Maintenance space
Before installation, a maintenance space shown in the figure on the right must be secured. Be sure tosecure this space during construction planning or installation.

Without storage box

With storage box

Maintenance space






(Unit: mm)

CAUTION
Do not drop or give strong shock to the calorimeter during transportation or installation.
Otherwise, the calorimeter may be damaged, or the explosion-proof performance may be lost.
When installing the calorimeter on a freestanding rack (fixed type), fix the freestanding rackwith anchor bolts.
If the calorimeter is to be fixed on the wall, install it properly where can hold its weight.
When performing construction work, prevent dust from entering the inside of the calorimeter.

17 / 45

3 How to Connect Wire

3-1. Description of terminal plate3

How to Connect Wire
3-1. Description of terminal plate
Open the front lid of the OHC-800 to find the terminal
shown in the figure below. The terminal plate has thelayout shown in the table below.

(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
(12)
(13)
(14)
(15)
(16)

Contact output
1

CONTACT
1

Contact output
2

CONTACT
2

Contact output
3

CONTACT
3

Power

FG
L/+
N/-

RS-485
communication
4 - 20 mA
external output

A
B
G
Y
Z
(+)
(-)

plate

Activates if the FUNCTION CHECK condition is met or the OUT
OF SPECIFICATION condition is met.
[No-voltage contact, contact capacity of 2 A, 30 VDC (resistanceload)]
Activates if the FAILURE condition is met.
[No-voltage contact, contact capacity of 2 A, 30 VDC (resistanceload)]
Activates if the MAINTENANCE REQUIRED condition is met.
[SSR contact, contact capacity of 20 W, 240 VAC (resistanceload)]
Functional Grounding (EARTH)
100 - 240 VAC ±10%, 50/60 Hz, max. 18 VA or
24 VDC ± 10%, max. 5 W

Input-output terminals for communication via RS-485
4 - 20 mA DC (insulated, source current type) maximum load
resistance of 300 Ω
Minimum resolution of 0.01 mA or less18 / 45

3 How to Connect Wire

3-1. Description of terminal plate

M4 is used as the terminal screws for the terminal plate. Attach an insulated ring terminal with insulating
coating for M4 to the tip of a cable for wiring.

NOTE
If you are considering the use of the RS-485 communication function, contact RIKEN KEIKI.

NOTE
Contact output 3 (SSR)Contact output 3 of the calorimeter makes SSR output.

AC power supply is required to drive the contact output.
Converting SSR contact into dry contact
Add an external relay.
Contact output 3 of the calorimeter makes SSR output. (Load specification: 75 - 264 VAC, 20 mA - 1 A)
It is not possible for a DC input unit to obtain SSR output.
In this case, add an external AC relay to convert SSR contact output into dry contact output.
<Wiring Diagram>
OHC-800(5) (6)

Hazardous location
Non-hazardous location
Relay
~
~

100 VAC
Input unitInstall an AC relay in the non-hazardous area.
Use a coil with specified voltage of 75 - 264 VAC and current of 20 mA - 1 A for the relay.
E.g.) MK3ZP (OMRON): Rated current 23.1 mA (100 VAC, 60 Hz)

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3 How to Connect Wire

3-2. Recommended cable

3-2. Recommended cable
Connected toPower (AC) line
Power (DC) line
4 - 20 mA line
Contact x 1 lines
Contact x 2 lines
Contact x 3 lines
RS485 line

Recommended cable

Cable overall outer diameter

CVV 1.25 sq/3-core
CVV 2 sq/3-core
CVVS 1.25 sq/2-core
CVVS 2 sq/2-core
CVVS 1.25 sq/2-core
CVVS 2 sq/2-core
CVVS 1.25 sq/2-core
CVVS 2 sq/2-core
CVVS 1.25 sq/4-core
CVVS 2 sq/4-core
CVVS 1.25 sq/6-core
CVVS 2 sq/6-core

Ø10.0
Ø11.0
Ø10.0
Ø11.0
Ø10.0
Ø11.0
Ø10.0
Ø11.0
Ø11.0
Ø12.0
Ø13.0
Ø14.0

Shielded cable of KPEVS etc.
0.75 sq/2P

Ø11.0

NOTE
The overall outer diameters must be checked because they may slightly vary between manufacturers.

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3 How to Connect Wire

3-3. Cable connection

3-3. Cable connection
As shown on the right side of the figure below, attach the parts in the following order: (1) cable gland, (2)clamp washer, (3) washer, (4) rubber seal and (5) washer to the cable, then connect the cable into lead-in
port through the enclosure by attaching an insulated ring terminal to the tip in order to complete theconnection to the terminal plate.
An unused cable lead-in port must be closed with a rubber seal and a seal plug as shown on the left of the
figure below.

Set screw for fastening
Cable lead-in ports (five)(5) Washer
Rubberseal(4) Rubber seal
(3) Washer(2) Clamp washer(Note: Place the rightside of the face)

Seal plug(1) Cable gland






CAUTION
Ensure the tightening torque for the cable gland and seal plug to be 40 Nm or larger.
If it is difficult to tighten the cable gland and seal plug, grease its screw part and then tighten
them with the tool.
After completing tightening the cable gland and seal plug, use a set screw for fastening toprevent it from loosening.
To improve noise immunity, connect the shield of the CVVS cable inside the enclosure.

The rubber seals, washers and clamp washers to be needed for cable connection vary depending on theoverall outer diameter of a cable to be used. The table below shows the relationships between the overall
outer diameters of cables and inner diameters of parts. Please specify parts needed for cables to be used.

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3 How to Connect Wire

3-3. Cable connection

Cable overall outer
diameter (mm)Rubber seal
Inner diameter (mm)WasherInner diameter (mm)Clamp washer
Inner diameter (mm)Ø10, Ø10.5

Ø11

Ø12

Ø10.8

Ø11, Ø11.5

Ø12

Ø14

Ø11.8

Ø12, Ø12.5

Ø13

Ø14

Ø12.8

Ø13, Ø13.5

Ø14

Ø14

Ø13.8

Inner diameter
Inner diameter

Inner diameter

Inner diameter ofrubber seal

Rubber seal

Washer22 / 45

Clamp washer

3 How to Connect Wire

3-4. Protective grounding

3-4. Protective grounding
Connect the calorimeter to the ground using the "external grounding terminal" or "No. (7) of the terminal
plate" shown in the figure below.

No. (7) of terminal
plate
External
grounding terminal






WARNING
Before turning on the calorimeter, never fail to connect it to the ground.
Ensure to connect the calorimeter to the ground for stable operation and safety.
Do not connect the grounding wire to a gas pipe.
Ensure the grounding to be D type grounding or equivalent (less than 100 Ω of the grounding
resistance).
Use cable lugs for the grounding wire without any slack or tangle for safe connection.

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3 How to Connect Wire

3-5. Precautions on electrical work

3-5. Precautions on electrical work






CAUTIONBe careful not to damage the internal electronic circuit when wiring. In addition, be careful not
to apply stresses on the calorimeter due to load or installation of cables.
Do not install the power cables and signal cables in parallel with motor power cables, etc.
When these cables must be installed in parallel for unavoidable reasons, put the power cables
and signal cables in a metal conduit and connect the conduit to the ground.
Use ring terminals.
Use appropriate cables to wire.

Using a stable power supply
Not only when the power is turned on but also when the calorimeter is restarted due to momentary
blackout, note that OHC-800 is switched to a warm-up status for 15 minutes and stops measurement forfunction check status (see Sections 4.1, "From display just after power-on to measurement start" and 4.4,
"Self-diagnostic and monitoring function").
To reduce risk of momentary blackout, use a UPS (uninterruptible power supply) or take other appropriate
action.
The calorimeter must be provided with the following power supply.
Power supply
voltage
100 VAC ± 10% - 240 VAC ± 10% [AC specification](Terminal voltage of 24 VDC ± 10% [DC specification]
the calorimeter)
Allowed time of
momentary blackout

Up to 40 milliseconds(The calorimeter recovers frommomentary blackouts that last 40
milliseconds or longer by restarting
itself.)Example of actions
Install a UPS etc. on the outside of thecalorimeter to ensure continuous
operation and activation.

OthersDo not use it with a power supply oflarge power load or high-frequency
noise.

Example of actions
Use a line filter etc. to avoid the noise
source if necessary.

24 / 45

3 How to Connect Wire

3-5. Precautions on electrical work

Introducing protective measures against lightning
If cables are installed outside the factory/plant, or if internal cables are installed in the same duct as thecables coming from outside the factory/plant, "inductive lightning surge" may be caused by lightning.
Because lightning acts as a large emission source while cables act as a receiving antenna, devices
connected to the cables may be damaged.
The occurrence of lightning cannot be prevented, and even cables installed in a metal conduit or under the
ground cannot be completely protected from inductive lightning surge caused by lightning.
Although complete elimination of damages caused by lightning is impossible, the following protective
measures can be taken.
Take appropriate measures in accordance with the importance of the facilities
and the environment.
Protection against
lightning

Grounding*

Provide protection by a lightning arrester (cable arrester).
Install a lightning arrester before the field devices and central processing
equipment to mitigate any risk due to inductive lightning surge transmitted
through the cable. For information on how to use a lightning arrester, pleasecontact the manufacturer.
In addition to lightning, there are more sources of surge noise. To protect devices
from these noise sources, the devices must be grounded.

The lightning arrester has a circuit to remove a surge voltage which damages field devices.
Therefore, signals may be attenuated by installing the arrester. Before installing a lightning
arrester, verify that it works properly.

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3 How to Connect Wire

3-5. Precautions on electrical work

Proper use of contact
If the contact output of this product is used on a line where large inductive load occurs, the following errors
may occur due to counter electromotive force generated at the contact.
Deposition, defective insulation or defective contact at the relay contact
Damage of any electric parts due to high-voltage generation
Abnormal operations by an out-of-control CPU

CAUTION
Do not use the contacts of the calorimeter directly for drive control over external devices thatgenerate large inductive load, such as a fluorescent lamp or large-scale motor.
To control a line where large inductive load occurs, provide an external relay for contact
amplification. However, because the coil of an external relay also involves inductive load,
select a relay at a lower voltage, and then protect the contact of the calorimeter with anappropriate surge absorbing part, such as a CR circuit.

To control a line where large inductive load occurs, protect the contacts of this product as shown in the
figure below.
OHC-800

Power
supplyContact





SK2

Load

Coil

SK1

Power
supplyExternal relay(low voltage relay)* SK1, SK2: Surge absorbing

Relay it with an external relay (contact amplification). At the same time, the surge absorbing partSK1 suitable for the specifications must be attached to the external relay.
In addition, the surge absorbing part SK2 must be attached to the loaded side of the external relay
if necessary.
It may be recommended that the surge absorbing part should be attached to the contact for certain
load conditions. It must be attached to an appropriate position by checking how the load is
activated.

26 / 45

4 How to Tube

4-1. Recommended external tubing system

4

How to Tube
4-1. Recommended external tubing system
If the sampling point is on a high-pressure line over 0.9 MPa, decompression must be performed outside
the sampling device. Decompression must be performed as close to the sampling point as possible toensure the quickest possible arrival of the measuring gas at the OHC-800. (Use the direct-insertion type ofpressure reducing valve if possible.)
Since the OHC-800 consumes approximately 300 mL/min of measuring gas, which is small, the bypass
flow rate must be increased to ensure quicker arrival of the gas.
If there is a low-pressure line of about 20 kPa, BYPASS OUT can be connected. If there is no low-pressureline, release the gas from BYPASS OUT into the atmosphere.
Since there is no limit on the arrival time of the reference gas, there is no problem unless the pressure
exceeds 0.9 MPa.
The gas from GAS OUT should be released into the atmosphere in principle, but it can be exhaust into an
exhaust duct equivalent to the atmospheric pressure (atmospheric pressure ±3 kPa) if any.
If RELIEF OUT converges on GAS OUT, use tubing with inner diameter of 10 mm or more (3/8" or more) if
the length of the tube is 20 m or shorter in order to decrease the load from the converging point todownstream.
The end point of a vent for atmosphere release should form an inverted "T" shape to prevent inflow ofrainwater or variations of exhaust pressure due to wind inflow.

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4 How to Tube

4-1. Recommended external tubing system

If the length is 20 m or
shorter,the inner diameter must be 10
mm or larger.

High-pressure line

Low-pressure line
0.02 MPa or less

Reference gas
0.9 MPa Max

Only during
maintenanceIf there is any potential risk of drain or dust inflow, install a trap or filter to prevent inflow of those foreign
substances.
Use of storage box

Storage box not used
RS-400-0□□□

Storage box used
RS-400-1□□□ (outdoor use)
RS-400-2□□□ (indoor use)

Connection of tubing
REF INSPAN IN
Swagelok fitting for 1/8" tube is used at all
BYPASS OUT
connections of tubing.
GAS IN
Swagelok fitting for 1/4" tube is used at all
GAS OUT
connections of tubing.
RELIEF OUTSwagelok fitting for 1/4" tube is used at all connections of tubing.

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4 How to Tube

4-2. Precautions on tubing work

The table below shows the guideline values for the "setting pressures of external pressure reducing
valves" and "bypass flow rates" corresponding to the "tubing diameters" and "tubing lengths" from theexternal pressure reducing valve to GAS IN of the sampling device in the tubing system shown on theprevious page.
Use this table only for your reference because it shows estimated values for assumed arrival time of six
seconds or shorter, without any view for upstream tubing structure from external pressure reducing valve
or filters installed at any point of the tubing.
Tubing length
10m

20 m

Setting pressure: 0.04 MPa
Bypass: Not required
Setting pressure: 0.1 MPa
Bypass flow rate: 2.5 - 5 L/min
Setting pressure: 0.1 MPa
Bypass flow rate: 5 - 10 L/min
Setting pressure: 0.1 MPa
Bypass flow rate: 10 - 20 L/min

Setting pressure: 0.2 - 3 MPa
Bypass flow rate: 2 - 5 L/min
Setting pressure: 0.1 MPa
Bypass flow rate: 5 L/min
Setting pressure: 0.1 MPa
Bypass flow rate: 10 L/min
Setting pressure: 0.1 MPa
Bypass flow rate: 20 L/min

Tubing diameterØ3, 1/8"
Ø6, 1/4"
Ø8, 5/16"
Ø10, 3/8"

Use tubing with a large inner diameter for GAS OUT and RELIEF OUT.
Ø6 - 4
Ø8 - 6GAS OUT
5 m or shorter
25 m or shorter
RELEF OUT
0.5 m or shorter4 m or shorterØ10 - 8----10 m or shorter

4-2. Precautions on tubing work
1)
2)
3)

4)
5)

Use stainless tubing.
After the tube is cut, its cut point may have a smaller inner diameter.
Use a file etc. to expand the inner diameter of the cut point.
Cut-dust of tubing may cause failures of the needle valve, flow rate detection mechanism, three-way
switching valve etc.
To remove cut-dust remaining inside of the tube, blow compressed air etc., into the tube before
connecting it to the calorimeter.
Determine a sampling point inlet for the measuring gas, considering the airflow of the measuring gasline, unevenness in the manufacturing process of the fuel gas.
Adjust the measuring gas equivalent to the ambient temperature before supplying it to the sampling
device.

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5 How to Adjust/Use Calorimeter5-1. How to start the gas detector

5

How to Adjust/Use
Calorimeter5-1. How to start the gas detector
1)
2)
3)
4)
5)

6)

Check that the external wiring has been done properly.
Check that the power supply voltage is compliant with the specification.
Rating: 100 - 240 VAC ±10%, 50/60 Hz or 24 VDC ±10% (The setting can be changed to either the
AC or DC specifications.)
Check that the external tubing has been connected properly.
Check that no leak occurs from a tube between the measurement location and gas inlet.
Turn on the measuring part "OHC-800" to start up the calorimeter.
(The cover of OHC-800 cannot be opened/closed in an explosion-proof area. Therefore, thecalorimeter needs to be installed with the internal power turned on, and it is started by turning on themain or external power switch.)
After turning on the power, wait until the 15-minute warm-up state is exited before use.

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5 How to Adjust/Use Calorimeter5-1. How to start the gas detector

Power terminal unit

Power switch
Power terminal unit with DC
specifications

Power terminal unit with AC
specifications

Warm-up finishes 15
minutes after power-on.

OHC-800 display

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5 How to Adjust/Use Calorimeter5-2. How to use three-way switching valve

5-2. How to use three-way switching valve
The three-way switching valves (CV) of UNIT-A and UNIT-C are used to switch the gas lines in thefollowing cases (1) to (3).
(1) In measuring a gas, a reference gas is supplied from REF.IN to the reference gas line of themeasuring part (OHC-800), and a measuring gas is supplied from GAS IN to the measuring gas line of
the measuring part (OHC-800).
(2) In performing a reference gas calibration, a reference gas is supplied from REF.IN to the reference
gas line and measuring gas line of the measuring part (OHC-800).
(3) In performing a span calibration, a reference gas is supplied from REF.IN to the reference gas line of
the measuring part (OHC-800), and a calibration (span) gas is supplied from SPAN IN to themeasuring gas line.
<(1) Gas Measurement>

Turn the three-way
switching valve handle
to the Sampling gas
idTurn the three-way
switching valve handle
to the REF GAS side.

UNIT-A
Supply sampling (measuring) gas

UNIT-C
Supply reference gas

Tubing diagram

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5 How to Adjust/Use Calorimeter5-2. How to use three-way switching valve<(2) Reference Gas Calibration>

Turn the three-way
switching valve handle to
the REF GAS side.

UNIT-C
Supply reference gas

Turn the three-way
switching valve handle to
the Calibration gas side.

UNIT-A
Supply calibration (reference) gas

Tubing diagram

33 / 45

5 How to Adjust/Use Calorimeter5-2. How to use three-way switching valve<(3) Span Calibration>

Turn the three-way
switching valve handle to
the SPAN GAS side.

UNIT-C
Supply reference gas

Turn the three-way
switching valve handle to
the Calibration gas side.

UNIT-A
Supply calibration (span) gas

Tubing diagram

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5 How to Adjust/Use Calorimeter5-3. How to use sampling parts

5-3. How to use sampling parts
5-3-1 Adjusting needle valve

V

Needle valve

V
2

UNIT-A

UNIT-CThe needle valves of UNIT-A and UNIT-C are used to adjust theflow rate of gases (measuring gas, reference gas or calibrationgas) supplied to the measuring gas or reference gas chamber ofthe measuring part OHC-800 to the specified value. Turn theneedle valve to the right (clockwise) to decrease the flow rate or to
the left (counterclockwise) to increase the flow rate.

Needle valve(1) UNIT-A needle valve V2: Adjusts the flow rate of sampling gas line.
(2) UNIT-A needle valve V: Adjusts the flow rate of calibration gas (span and reference calibration gases)line.
(3) UNIT-C needle valve V: Adjusts the flow rate of reference gas line.

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5 How to Adjust/Use Calorimeter5-3. How to use sampling parts

5-3-2 Adjusting pressure reducing valve

Pressure gauge

Pressure reducing
valve

UNIT-B

UNIT-CThe pressure reducing valves of UNIT-B and UNIT-C are used to adjust the pressure of gases (measuringgas, reference gas or calibration gas) supplied to the measuring gas or reference gas chamber of themeasuring part OHC-800 to the specified value. Turn the needle valve to the right (clockwise) to increase
the pressure or to the left (counterclockwise) to decrease the pressure. Check the pressure with thepressure gauge located above the valve.
After adjusting the pressure, turn the stopper to the left (counterclockwise) and fix the valve to avoid
operational error.

UNIT

UNIT-B

Model

RS-400-□１１□
RS-400-□１２□

Valve

UNIT-C
RS-400-□１３□

RS-400-□１１□
RS-400-□１２□
RS-400-□１３□
Valve

Valve

Appearance
Stopper (fixed)
Stopper (fixed)

Stopper (fixed)

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5 How to Adjust/Use Calorimeter5-3. How to use sampling parts

5-3-3 Bypass line
Since the flow rate of measuring gas requiredfor proper operation of OHC-800 is small(approx. 300 mL/min), sampling needs to be
performed with a relatively large flow rate to
the sampling device, and unused gas needs to
be bypassed in order to shorten the delay timein the tube between a sampling point and thesampling device. A bypass flow rate can be set
to an arbitrary value within the range specified
by the selected flow meter.

Needle valve installed
Flow meter

UNIT-B

Sampling device model and UNIT-B flow meter measuring range
0.5 -5 L/min
0.03 MPa
RS-400-□11□
RS-400-□12□

1 - 10 L/min

0.3 MPa

RS-400-□13□

2 - 20 L/min

0.1 MPa37 / 45

5 How to Adjust/Use Calorimeter5-3. How to use sampling parts

5-3-4 Relief valve
The relief valve of UNIT-D is used as a safety valve to prevent the measuring part OHC-800 from being
damaged by excessive pressure.
The relief valve is released when the specified pressure (10 kPa) or more is applied to the valve, and thepressure is transferred to the RELEFE OUT gas line.
To OHC-800

To OHC-800

UNIT-A
From three-way
switching valve (CV)UNIT-C
From needle valve(V)

To RELIFE OUT

To RELIFE OUT
Relief valve

UNIT-D
Tubing diagram

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5 How to Adjust/Use Calorimeter5-4. How to adjust reference gas flow rate

5-4. How to adjust reference gas flow rate
1)

Check that a reference gas is supplied
from REF IN (0.05 - 0.9 MPa).

2)Adjust the pressure reducing valve PR sothat the pressure gauge PG on UNIT-C
reads 0.03 MPa, and then fix the valve.

3)

Turn the three-way switching valve (CV) on
UNIT-C to the REF.GAS side.

4)

Turn the three-way switching valve (CV) on
UNIT-A to the Calibration gas side.

5)

Adjust the needle valve V on UNIT-C sothat the black circle that indicates REF flowrate comes to the middle of the scale.

6)

Adjust the needle valve V2 on UNIT-A sothat the black circle that indicates GAS flowrate comes to the middle of the scale.

Tubing diagram

OHC-800 display

Displays the flow rate of the reference gas(REF). Make adjustment so that the black circle
comes between the two solid lines that represent
the upper (right) and lower (left) limits. *When adjusted to the middle of the scale, theflow rate is about 10 mL/min.

Displays the flow rate of the measuring gas(GAS).
Make adjustment so that the black circle comes
between the two solid lines that represent theupper (right) and lower (left) limits. *When adjusted to the middle of the scale, theflow rate is about 300 mL/min.

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5 How to Adjust/Use Calorimeter5-5. How to adjust measuring gas flow rate

5-5. How to adjust measuring gas flow rate
1)

Check that a measuring gas is supplied
from GAS IN.

2)Adjust the pressure reducing valve PR sothat the pressure gauge PG on UNIT-B
reads the following specified value , andfix it with the stop valve.
Sampling
device model

the specified value

RS-400-□11□

0.03 MPa

RS-400-□12□

0.3 MPa

RS-400-□13□

0.1 MPa

3)

Adjust the needle valve installed flow
meter FL on UNIT-B to determine thebypass flow rate (it can be set arbitrarily
within the flow meter measuring range).

4)Turn the three-way switching valve on
UNIT-A to the Sampling gas side.

5)

Adjust the needle valve V1 on UNIT-A sothat the black circle that indicates GAS
flow rate comes to the middle of the scale.

Tubing diagram

Displays the flow rate of the reference gas(REF). Make adjustment so that the black circle
comes between the two solid lines that represent
the upper (right) and lower (left) limits. *When adjusted to the middle of the scale, theflow rate is about 10 mL/min.

Displays the flow rate of the measuring gas(GAS).
Make adjustment so that the black circle comes
between the two solid lines that represent theupper (right) and lower (left) limits. *When adjusted to the middle of the scale, theflow rate is about 300 mL/min.

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5 How to Adjust/Use Calorimeter

5-6. How to adjust calibration (standard) gas flow rate

5-6. How to adjust calibration (standard) gas flowrate
1)

Connect a standard gas cylinder to SPAN
IN.

2)

Adjust the secondary pressure of thecylinder to 0.03 MPa.

3)

Turn the three-way switching valve on
UNIT-A to the Calibration gas side.

4)

Turn the three-way switching valve on
UNIT-C to the SPAN GAS side.

5)

Adjust the secondary pressure of thecylinder so that the black circle thatindicates GAS flow rate comes to the
middle of the scale.
(If it is difficult to fine-tune the flow rate,
make adjustment using the needle valve
V2 on UNIT-A.)

Tubing diagram

Displays the flow rate of the reference gas(REF). Make adjustment so that the black circle
comes between the two solid lines that represent
the upper (right) and lower (left) limits. *When adjusted to the middle of the scale, theflow rate is about 10 mL/min.

Displays the flow rate of the measuring gas(GAS).
Make adjustment so that the black circle comes
between the two solid lines that represent theupper (right) and lower (left) limits. *When adjusted to the middle of the scale, theflow rate is about 300 mL/min.

41 / 45

6 Maintenance

6-1. Maintenance item

6

MaintenanceThis product is supposed to be operated continuously over a long period of time. Regular maintenance isnecessary to maintain the appropriate performance during the period of use.

- Maintenance Contract We recommend you to conclude a maintenance contract with us for regular maintenance including
span adjustment, adjustment, maintenance etc. to ensure stable operation and accuracy of thecalorimeter.
Please contact RIKEN KEIKI for more information on a maintenance contract.

NOTE
See the separate volume "OHC-800 Operating Manual" for the maintenance of the measuring part (OHC800).

6-1. Maintenance item
Maintenance area/item

Criteria

Actions

Check that the black circles that indicate theReference gas (REF) andAdjust the flow rates
reference gas (REF) and measuring gas (GAS) flow
measuring gas (GAS) flowusing the respective
rates stay between the two solid lines that represent
rates
needle valve.
the upper and lower limits.

6-2. Procedures to store the calorimeter or leave it
for a long time(1) If the calorimeter is to be left unused for a long time, expel the measuring gas from the tubing insidethe device using fresh air, nitrogen etc.
(2) Storage conditions
The calorimeter must be stored under the following environmental conditions.
(1) In a dark place under the normal temperature and humidity away from direct sunlight(2) In a place where gases, solvents or vapors are not present

42 / 45

7 Definition of Terms

6-2. Procedures to store the calorimeter or leave it for a long time

7

Definition of Terms
The terms used in this manual are defined as follows.
Measuring gas:

Gas used to measure calorific value, density and WOBBE index on thisproduct.

Reference gas:

Gas used on an optical sensor unit as a reference for measuring therefractive index of a measuring gas. The gas type varies depending on
the product specifications.

Reference gas
calibration(REF CAL.):

Operation for adjusting the reading when measuring the reference gas.

43 / 45

8 Product Specifications

8-1. Product Specifications

8

Product Specifications
This sampling device is used in combination with the measuring part OHC-800. Therefore, the productspecifications include OHC-800.

8-1. Product Specifications
Model
Measuring principle
Measuring gas
Measuring targets
Measuring range
Sampling method
Selfmonitoring/diagnostic
function

Display

External Output 1
External Output 2
External Output 3
Contact output 1
Contact output 2
Contact output 3
How to Operate
Power supply
Protection class
Ambient temperature
Ambient humidity

OHC-800
Opt-Sonic calculation through measurement of refractive index and soundspeed
See "Measuring gas specification sheet" attached.
Calorific value, density (specific gravity) and WOBBE index
See "Measuring gas specification sheet" attached.
Constant-flow-rate gas introduction using external sampling devices
Status monitoring using four classification categories

FAILUREFUNCTION CHECKMAINTENANCE REQUIREDOUT OF SPECIFICATION
Full-dot LCD (with backlight)
EV lamps
Green:
Lights up at power-on.
Orange: Lights up in conjunction with Contact Output 1.
Red:
Lights up in conjunction with Contact Output 2.
Green:
Lights up in conjunction with Contact Output 3.
4 - 20 mA DC (insulated, source current type) maximum load resistance of300 Ω
Minimum resolution of 0.01 mA or less
RS-485 communication function
IrDA communication output (for maintenance)
Activated if the FUNCTION CHECK or
OUT OF SPECIFICATION condition is met.*[No-voltage contact, contact capacity of 2 A, 30 VDC (resistance load)]
Activated if the FAILURE condition is met.*[No-voltage contact, contact capacity of 2 A, 30 VDC (resistance load)]
Activated if the MAINTENANCE REQUIRED condition is met.*[SSR contact, contact capacity of 20 W, 240 VAC (resistance load)]
Operation using a magnet control key(The calorimeter can be operated while maintaining the explosion-proof
performance.)
100 - 240 VAC ±10%, 50/60 Hz, max. 18 VA
or 24 VDC ±10%, max. 5 W (The setting can be changed to either the AC or
DC specifications.)
Equivalent to IP66 or IP67
Japan EX： -20 to +57°C (no sudden changes)
ATEX/IECEx： -20 to +60°C (no sudden changes)
95%RH or less (non-condensing)
44 / 45

8 Product Specifications
Measuring gas
temperature
Outer dimensions
WeightExplosion-proof
structure
Explosion-proof class

8-1. Product Specifications
Same as ambient temperature
Approx. 286 (W) x 453 (H) x 150 (D) mm
Approx. 23 kg
Flame-proof enclosures
Japan EX
ATEX
IECEx

： Ex d ⅡB + H2 T4： Ⅱ 2G Ex db ⅡB + H2 T4 Gb： Ex db ⅡB + H2 T4* The operating conditions of contacts can be changed.
* Specifications subject to changes without notice.

45 / 45