ROTATING MACHINERY SERVICES, INC.

RMS

VOLUME 9, ISSUE 3
JULY - SEPTEMBER 2013

The Finish Line

Phone 484-821-0702

RMS POWER SOLUTIONS

Fax 484-821-0710

www.rotatingmachinery.com

By Charles (Chot) Smith

We have some exciting news fromthe RMS Power Solutions ServiceShop. We pulled the shop expansion
project plans off the shelf, dusted
them off, renewed all of the permits
and are due to break ground by mid
fall and be under roof prior to any
bad weather.
The expansion will consist of an additional 10,000 sq. ft. of floor space.
Included in this space in addition tofour assembly bays will be an abrasive blast
cleaning facility, a weld shop, and a nondestructive (NDT) testing bay. The expansion will also have an additional 10 feet under the hook of a 35 ton crane.
We also have recently commissioned ourBullard 90” swing vertical boring mill andare in the process of locating a large horizontal boring mill. As usual, our rotor shop
is overflowing with axial and centrifugal
Bullard Dynatrolcompressor, expander, and steam turbine rotors which are in various stages of inspection and refurbishment.

What’s Inside
Rule of Thumb

2Turbine Steam Purity

2Don’t Abandon thatShaft!

3Shaft Seal Study

4Quality Control

4Blade Runners

5Motoring Along6

Anti-Fouling Coatings

6Promotion

7

New Employees

7

RMS IMPORTANT NUMBERS
HOUSTON SALES OFFICE:
Kurt Diekroeger
281-340-8520 (O)713-898-1015 (C)TENNESSEE SALES OFFICE:
Mike Spangler
865-981-9831 (O)484-896-8438 (C)LOUISIANA SALES OFFICE:
Remus Creel
225-291-4974 (O)225-939-4680 (C)POWER RECOVERY TRAIN (PRT) ROUND TABLE
Rotating Machinery Services will be hosting a Power Recovery Train Round Table scheduled for October 29 and October 30, 2013. A welcome reception
will be held on Monday, October 28th.

UPCOMING
CONFERENCES
42ND TURBOMACHINERYSYMPOSIUM

If you are interested in attending, you can download the registration form on
our website at http://www.rotatingmachinery.com/conferences.html or you cancontact Don Shafer or Kathy Ehasz at 484-821-0702.

George Brown Convention
Center in Houston, TX
OCT. 1 - 3

If you have a topic, question or problem area for the Round Table, please emailDon Shafer at dshafer@rotatingmachinery.com.

GMRC GAS MACHINERYCONFERENCE

We have a few seats available. RSVP as soon as possible!

BOOTH 740

Albuquerque Convention Ctr.
Albuquerque, NMOCT. 6 - 9

BOOTH 643

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ROTATING MACHINERY SERVICES, INC.

Page 2

RULES OF THUMB - TURBOMACHINERYBy Neal Wikert

Flange Slotting

The purpose of keyhole slotting the O.D. of a flange in high temperature machinery is to eliminate the ability of the outer portion of the flange to carry hoopstress. Doing this reduces thermal stresses by allowing the cooler outer portionof the flange to expand less than the hotter bore region. The end result is lesslong-term distortion. Slotting every third bolt hole is a good rule of thumb andslotting more often provides safety margin.

SHCS removal:

Heat the head of the cap screw until cherry red. Allow cap screw to cool momentarily so that heat can soak down the threads. Turn to remove. Cap screw
will loosen.

Hex nut removal:

To remove hex nuts, heat one of the hex flats until red and break nut loose. On
Allen head bolts, heat down in the Allen head and break loose. This heat effectively loosens the nut and gives room for corrodents to move.

Large Joint nuts

(Hex Cap nut with heater hole) In the absence of a stud heater, shield casing jointwith insulation. Aim torch heat down the center stud heater hole. After heating,quickly break nut while stud is elongated from heat.

Gears – HelicalGears are generally manufactured from 4340 through hardened to a Brinell rangeof 340 – 370. Above a surface speed of 7000 ft./min. the gear teeth need to beground to give the part the accuracy needed for spinning at these speeds.

PerformanceStandard conditions:ISO:
59 deg. F, Sea Level (14.696 psia), 60% R.H.
NEMA: 80 deg. F, 1000 ft (14.17 psia)API:
60 deg F, 14.7 PSIA, Dry (0% RH)

TURBINE STEAM PURITY

By Scott MacFarlane

When it comes to steam turbines, the steams purity is a prevailing concern to the turbine’s functionality and life
expectancy. Steam purity is defined as the amount of solid, liquid or vaporous contaminates found in the steam.
Basically, any particles beside the pure steam are considered contaminates and these particles can have a severely
detrimental effect to the overall operation of the turbine. These
Manufacturers Recommended
contaminates can originate from many different sources
Steam Purity Limits
throughout the process of converting the feed water to steam.
Boiler carryover, feed water impurities and vaporization of silica
Sodium
5 - 20 ppb
and other compounds are just a few examples. There are indusSilica
10 - 20 ppb
trial steam contaminate limits set by manufactures that should
be followed to determine if the steam is acceptable. The chart
Chlorides
3 - 15 ppb
on the right is an average turbine manufacturers recommended
Sulfates
3 - 15 ppb
limit for some commonly found contaminates.

Volume 9, Issue 3
TURBINE STEAM PURITY (Con’t)

Page 3RMS

By Scott MacFarlane

Reduced steam purity can cause internal components of the turbine to accumulate deposits and cause severe corrosion. The more serious types of corrosion are stress corrosion cracking and corrosion fatigue. Stress corrosion cracking isthe collaboration of corrosion and mechanical stresses to causea failure by cracking the surface. Corrosion fatigue is the collaboration of corrosion and alternating or cycling stresses thatcauses a rupture of the surface, which in turn accelerates thecorrosion. These specific cases of failure are particularly detrimental during cold startups due to large condensation of steam.
When the turbine reaches its operating temperature, the condensate evaporates leaving concentrated contaminates on thesurface. Unfortunately these concentrations of contaminates
mainly form on hard to reach surfaces where the steam’s flow
cannot provide a washing effect. These surfaces also happen to be heavily stressed areas which will increase thechances for stress corrosion failures. Rotor blades and vanes manufactured from an AISI 403 12%Cr stainless steel
is the most commonly used material to prevent these failures. Other potential hazards that are associated with thesteam’s purity come in the form of erosion, particle accumulation, flow obstruction, high thrust loading and stickingof valve stems. An example of flow path deposits from steam impurities can be seen in the photograph.

DON’T ABANDON THAT SHAFT JUST YET!

By Dirk Paraschos

RMS works at providing services to our customers that can often save thousands of dollars and months of downtime. Recently, we have had quite a few projects where we have reassembled rotors with abandoned compatible
parts. By reworking and providing a few new parts in a timely manner, RMS is able to meet customer needs.
This past month, we shipped a rebuilt compressor rotor to a customer one month ahead of their turnaround. We
were able to accomplish this task by re-using an abandoned shaft, impellers from a second rotor, and reworking theexisting sleeves and balance piston. By weld repairing the abandoned shaft’s damaged journals we were able to makeit reusable. The 5 impellers de-stacked in our shop needed to be weld repaired and re-riveted. The re-riveting wasa huge job made manageable by our experienced machinists. Over 65% of the rivets needed to be replaced on threeof the impellers, while the other two needed blending and weld repair. After reworking the sleeves and balance
piston, designing and machining all new support rings we were ultimately able to deliver the customer a rebuilt rotor that met Engineering requirements. The whole project from start to finish was accomplished in 18 weeks byadhering to our Project Schedule and support from all the departments at RMS. This saved the customer thousandsof dollars by not having to purchase all new components and not to mention the revenue that would have been lost
due to additional down time.
This is a just one successful example of many projects that are currently flowing through our shop. By paying constant attention to the details of the project schedules we have been able to deliver quality service to our many different customers all across the country and around the world.

RMS

Page 4

Page 4ROTATING MACHINERY SERVICES, INC.

SHAFT SEAL STUDYRMS

By Tony Rubino, P.E.

Rotating Machinery Services, Inc. was contracted to do a shaft seal improvement study for I-R CDP24 single stage
pipeline compressors on natural gas pipeline service. The purpose of the study was to determine how to minimize
or eliminate seal oil carryover into the pipeline. The customer reported that they were experiencing as much as
200 gal/day make up oil requirements with the existing bushing oil seal arrangement on some of the compressors.
The customer also described complaints received from power plants along the pipeline that the seal oil carryover
was the cause of combustion system fouling of their gas turbines drawing combustion gas from the pipeline.
The scope of the study included a site visit to perform compressor dimensional and documentation inspections by
RMS during a maintenance outage performed by the customer. The customer’s preference was to convert to a drygas seal. The result of the study and the follow-on execution determined that a dry gas seal was not feasible due tospace limitations. Working in cooperation with Kaydon (seal supplier), a suitable mechanical face seal was designed
and manufactured. RMS also performed controls system and rotordynamics reviews to ensure proper integration of
the new seals. New pressure dam journal bearings were provided to improve compressor rotor stability. After approximately one month operation, the customer could not provide oil usage data since the oil level had notchanged appreciably. In the customer’s words, “The seals are doing what they are supposed to be doing”. The teamapproach and collaborative effort between the customer, Kaydon and RMS got it done right the first time.

QUALITY CONTROL

By Robert DeHart ASQ CQTPortable Metrology – Co-ordinate Measuring Machine (CMM)
Portable measuring devices such as CMMs can facilitate the capture of heretofore unobtainable geometric attributes of measured parts. However, measurements acquired using a portable measurement device require an evaluation of the method and the process of taking the measurements to ensure the integrity of data and to understandthe implications of measurement results for decisions made about the product or process.
Changes in the measuring process such as temperature fluctuations, vibration, the stability of the instrument andthe fixturing of the part being measured can affect the assignment of a number to a measurement characteristic.

Volume 9, Issue 3
QUALITY CONTROL (Con’t)

Page 5

Page 5RMS
RMS

By Robert DeHart ASQ

For example, in situ measurement of blade cross sections and flow path characteristics of an axial compressor rotor
must be preceded by the fixturing of the rotor and the CMM to ensure zero relative movement. A co-ordinate system is created using the system software to establish x, y zeros at both ends of the rotor. During the measurement
process, these zeros are continuously monitored by re-measurement. Any significant change would require compensation, re-zeroing or re-starting the measurement process from scratch.
Accurate measurements will enhance the designer’s confidence in rerate recommendations such as:
 increasing pressure rise by adding stages, changing blade camber or increasing the speed.
 increasing the flow by adding a new stator casing, longer blading, stagger angle decrease, speed increase.

.

RMS BLADERUNNERS - LEHIGH VALLEY HEALTH NETWORK VIA RELAY
For the third consecutive year, RMS participated in the Lehigh Valley Health Network Via relay race on September
8th. The race, which benefits children and adults with disabilities like Autism, Cerebral Palsy and Down syndrome, isa certified marathon course from Allentown toEaston PA along the scenic Lehigh Canal and River.
The RMS team Blade Runners this year were, in order of relay legs, Sydney Gross, Corey Jones, JoanBerg, Bob Klova and Neal Wikert. Sydney also wenton from the first leg to complete the marathon.
The weather was beautiful and RMS, in the spirit ofcontinuous improvement, bettered their last year’stime by 20 minutes. There was a record turnout forthe marathon this year in the wake of the Boston
bombing owing to the fact that it is one of the lastqualifying races of the season for the Boston Marathon.

RMS

Page 6ROTATING MACHINERY SERVICES, INC.

MOTORING ALONG

By William Sullivan, P.E.

Recently the structural analysis group at RMS stepped out of its turbomachinery paradigm and entered the electricworld of motor vibration.
One of our customers was having chronic vibration problems with the drive motor for a power recovery train.
Proposed solutions to the vibration issue included a coupling change and a motor bearing redesign. When field
vibration data pointed to the possibility of a resonance condition close to operating speed, the customer, a major
refinery, asked RMS to get involved.
Exploring the motor vibration problem was a perfect fit for ouranalytical capabilities and experience. We constructed a finite
element structural model of the motor that consisted of the basestructure, casings, end-walls, bearing housings and rotor (SeeFigure 1). We then ran a parametric analysis consisting of 25
different cases. Using the frequencies and deflected modeshapes as guides, we were able to identify some relatively inexpensive and easily implemented modifications that would reduce
vibration response significantly.
Some of the recommended modifications were implemented, themost significant being stiffer motor end bells of RMS design, andmotor vibrations have been reduced to more typical levels andhave remained consistently low since start-up over a year ago.

ANTI-FOULING COATINGS FOR COMPRESSOR FLOWPATHS

By Marc Rubino

Turbo compressors in petrochemical service are often subjected to gradual, destructive phenomena, such as corrosion and fouling, in the flowpath. Compressor fouling wanes efficiency since unwanted process particles accumulate
on rotating and stationary flowpath components. In time, the build-up from fouling can impede flow capacity, negatively influence dynamic rotor balance, and obstruct running clearances. In addition to online performance degradation, fouling and corrosion damage will extend outage time and increase overhaul costs.
Anti-fouling corrosion resistant coatings are engineered to enhance online performance and prevent corrosion to
the base metal. They are typically multi-layer systems consisting of a barrier, inhibiting, and sacrificial coating. Thebarrier or top coat prevents corrosion by isolating and sealing the base metal from damaging liquids. If the barrier
coat remains intact, corrosion is unable to occur. Under the barrier coat, one or more inhibiting or intermediatecoats are applied to chemically alter corrodants. The corrodants are essentially rendered inert as they penetrateinto the inhibiting coating. And finally, a sacrificial or base coat is designed to “sacrifice” itself by corroding insteadof the base metal. Once the base coat is depleted, it can no longer corrode in place of the base metal.
RMS was recently contracted to overhaul two
Cooper-Bessemer model RA(6)-4B inner barrel
assemblies. The overhaul for both barrels included
rotor destacking, diaphragm disassembly, cleaning,
non-destructive examination, flowpath component
repair or replacement and reassembly. Major replacement parts included impellers, inlet guides, allinterstage labyrinth seals and new/refurbishedjournal and thrust tilt-pad style bearings.

Volume 9, Issue 3

Page 7RMS

ANTI-FOULING COATINGS FOR COMPRESSOR FLOWPATHS (Con’t)
Most relevant to this article, however, was the improvement coating of the impellers, diaphragms, inlet guides, andother flowpath components. Through a collaborative approach between RMS and Praxair, an anti-fouling coating
system was specified and successfully applied to all critical parts. According to Praxair, the selected coating system,“…provides an aerodynamically smooth, non-reactive, non-stick outer surface that resists wetting and the foulingbuild-up it causes.” The preventative multi-layer coating is designed to extend the time between outages, enhance
performance, and reduce repair costs. With the expertise and quality provided by RMS and its dedicated suppliers,
the overhauled compressors’ aerodynamic assemblies are expected to exceed the OEM’s performance and reliability.

CONGRATULATIONS KELLY HILL

By RMS Staff

We are pleased to announce the promotion of Kelly Hill to Staff Accountant. Kelly joined RMS
in 2012 as an Administrative Assistant. She previously worked at Hoffman Manufacturing Inc., astheir Accountant. Kelly brings with her 4 years Accounting experience in an industrial environment.
Kelly graduated from Northampton Community College in 2004 with an Associate’ Degree inBusiness Administration. Her future plans are to pursue her Bachelors Degree in Accounting/Finance.

WELCOME RMS NEW EMPLOYEES

By RMS Staff

MAURY HENRICHSEN, P.E.
PRODUCT MANAGER - CENTRIFUGAL COMPRESSORS

Maury brings with him 34 years’ machinery engineering experience in the process/industrial gas and power generation industry participating in OEM, aftermarket, service, and end user roles. He served various
engineering and design roles with GE Energy, Bently Nevada, Conmec, and A-C Compressor. He also
served as an internal machinery consultant for industrial gas companies Air Liquide America and Air
Products and Chemicals. Primary experience includes centrifugal compressor design and rerates as wellas field performance/mechanical integrity evaluation. He also has extensive experience with field vibration analysis and troubleshooting. Maury graduated with a BS in Mechanical Engineering from the South
Dakota School of Mines & Technology and maintains a Professional Engineering license with the State of California.
BETH VETOVITZAPPLICATIONS ENGINEER

Beth is a business professional who has 20 years of experience with meeting customers’ needs. Herroles have included proposals, customer service and contract management related to equipment modifications and spare parts. She has spent her career supporting customers from many different manufacturing and service industries. She graduated from Temple University with a BBA in Marketing and from DeSales University with an MBA in Management.
CHARLENE KRATZERADMINISTRATIVE ASSISTANT

Charlene Kratzer has joined RMS, Inc. as our Administrative Assistant. She brings with her 2 years ofcustomer relations experience. She is currently continuing to work on getting her Associate’s degree inMathematics at Northampton Community College.

RMS

Rotating Machinery
Services, Inc.

2760 Baglyos Circle
Bethlehem, PA 18020
Phone: 484-821-0702 / Fax: 484-821-0710
www.RotatingMachinery.com

PRODUCT LINESAXIAL COMPRESSORS •CENTRIFUGAL COMPRESSORS •EXPANDERS • GAS TURBINES •POWER TURBINES • STEAM TURBINES