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CTI Journal, Vol. 27, No. 2 1

The CTI Journal

(ISSN: 0273-3250)

PUBLISHED SEMI- ANNUALLY

Copyright 2006 by The CoolingTechnology Institute, PO Box 73383,Houston, TX 77273. Periodicals

postage paid at FORT WORTH, Texas.

MISSION STATEMENT

It is CTI’s objective to: 1) Maintain andexpand a broad base membership of

individuals and organizationsinterested in Evaporative HeatTransfer Sys tems (EHTS), 2) Identifyand address emerging and evolvingissues co ncerning EHTS, 3) Encour-age and support educationalprograms in various formats toenhance the capabilities andcompetence of the industry to realizethe maximum benefit of EHTS, 4)Encourge and support cooperativeresearch to improve EHTS Technologyand efficiency for the long-termbenefit of the environment, 5) Assureacceptable minimum quality levelsand performance of EHTS and their components by establishing standardspecifications, guidelines, and

certification programs, 6) Establishstandard testing and performanceanalysis systems and prcedures for EHTS, 7) Communicate with andinfluence governmental entitiesregarding the environmentallyresponsible technologies, benefits,and issues associated with EHTS, and8) Encourage and support forums andmethods for exchanging technicalinformation on EHTS.

LETTERS/MANUSCRIPTS

Letters to the editor and manuscriptsfor publication should be sent to: TheCooling Technology Institute, PO Box73383, Houston, TX 77273.

SUBSCRIPTIONS

The CTI Journal is published inJanuary and J une. Complimentarysubscriptions mailed to individuals inthe USA. Library subscrip tions $20/yr.Subscriptions mailed to individualsoutside the USA are $30/yr.

CHANGE OF ADDRESS

Request must be received atsubscription office eight weeks beforeeffective date. Send both old and newaddresses for the change. You mayfax your change to 281.537.1721 or email: [email protected].

PUBLICATION DISCLAIMER

CTI has compiled this publicationwith care, but CTI has not Investi-

gated, and CTI expressly disclaimsany duty to investigate, any product,service process, procedure, design,or the like that may be descri bedherein. The appearance of anytechnical data, editorial material, or advertisement in this publicationdoes not constitute endorsement,warranty, or guarantee by CTI of anyproduct, service process, procedure,design, or th e like. CTI does notwarranty that the information in thispublication is free of errors, and CTIdoes not necessarily agree with anystatement or opinion in thispublication. The entire risk of the useof any information in this publicationis assumed by the user. Copyright

2006 by the CTI Journal. All rightsreserved.

ContentsFeature Articles10 A Performance Compar ison of Counterflow Reduced

Fouling FillsToby L. Daley, P.E.

34 Large Scale Mechanical Equipment Replacement - SimpleSteps for SuccessDavid M. Suptic P.E. LLC

44 Roulette And Mechanical Vibration Switches: What AreYour Odds?Gene Ort

60 Improving Localized Corrosion in a Complex Cooling

Water SystemMichael H. Dorsey,Kevin Daigle,and A.F. Brunn

Special Sections68 CTI Licensed Testing Agencies

70 CTI ToolKit

Departments02 Meeting Calendar

04 View From the Tower

06 Editor’s Corner

08 Data Sheet

s e e . . .p a g e 4 4

s e e . . .p a g e 1 6

s e e . . .p a g e 3 8



CTI Journal, Vol. 27, No. 22

CTI Journal The Official Publication of The Cooling Technology Institute

Vol. 27 No.2 Summer 2006

Journal CommitteePaul Lindahl, Editor-in-Chief

Art Brunn, Sr. Editor Virginia Manser, Managing Editor/Adv. Manager Donna Jones, Administrative AssistantGraphics by Sarita Graphics

Board of DirectorsSteve Chaloupka, President

Thomas Bugler, Vice President

Rich Altice, Secretary

Dennis (Denny) P. Shea, Treasurer

Robert (Bob) Giammaruti, Director

Richard (Rich) Harrison, Director

James Kanuth, Director

Ken Kozelski, Director

Terry Ogburn, Director Mark Shaw, Director

Ad dr ess al l co mm un ic at io ns to :Virginia A. Manser, CTI Administrator Cooling Technology InstitutePO Box 73383Houston, Texas 77273

281.583.4087281.537.1721 (Fax)

Internet Address: http://www.cti.org

E-mail: [email protected]

FUTURE MEETING DATES

Committee Annual

Workshop Conference

July 9-12, 2006 February 4-7, 2007

Sheraton Sand Key Resort Omni Corpus Christi HotelClearwater, FL Corpus Christi, TX

July 8-11, 2007 February 3-7, 2008

The Westin La Cantera The Westin Galleria

San Antonio, TX Houston, TX

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Member







View From The Tower

S t e v e n Ch a l o u p k a

P r e s i d e n t

I want to thank all attendees and participants to

the 2006 Annual Conference for making it the best

meeting we have had in a long time. Continuing

education, fellowship, networking, progress withstandards and codes; all accomplished at the con-

ference! When evaluating personal time spent vs.

cost of participation, I think CTI is offering a pre-

mier value to our industry.

Time flies, and if I read my calendar correctly,

July 9th is rapidly approaching. You might ask

to keep pace with technology advancements. I

hope to see you at this upcoming meeting.

Speaking of the Summer Committee Workshop

I would like to personally invite any and alowner/operators to attend this meeting. We need

your input into the CTI codes and standards

After all, these are for your ultimate benefit. If

you are not able to attend the meeting, but would

like to participate in committee work, please let

me know and I will be happy to get you con-

“What happens on July 9th?” Well, that is the beginning of

the CTI Summer Committee Workshop being held from July

9th through July 12th at the Sheraton Sand Key Resort in

Clearwater, Florida. This is the meeting in which the three

standing committees of Performance & Technology, Water Treating and Engineering Standards & Maintenance are able

to review progress on standards and codes. This is truly the

backbone of CTI and the means in which new standards

and codes are created, plus updating our existing documents

nected with the right people that match your interests and

expertise.

I want to personally welcome Cleanair Engineering, Inc. and

McHale & Associates, Inc. as our two newest CTI licensed

testing agencies. These two new additions bring the CTIofficial licensed testing agencies to four, joining existing com-

panies of Cooling Tower Technologies, Pty., Ltd. and Cooling

Tower Test Associates, Inc. I encourage all owner/opera

tors to use these CTI licensed agencies for performance and

drift code verification on any new or rebuilt cool-

ing towers. By using these licensed agencies

you are assured of accurate data for adherence

to codes and standards. Just one more way CT

can help owners and operators maximize the per-

formance of their cooling towers.

If you have any ideas, suggestions or concernsabout CTI that you would like to discuss with

me, please feel free to contact me. I would be

very interested in discussing anything that migh

improve the offerings of CTI.

Steven Chaloupka,

CTI President












Performance and Testing Program

(Accoustical - Drift - Thermal Testing Agencies)

A hearty welcome to our two newest Multi-Agency Testing Companies, Clean Air Engineering and McHale & Associates

Inc. Here is an introductive discription for both companies to help you get acquainted with each.

Clean Air Engineering, Powell, Tennessee - Clean Air Engineering is proud to continue the relationship that its staff

Thermaland

Drift

Data Sheet:

McHale & Associates, Inc. - is pleased to announce the addition of the CTI Licensefor Drift Testing to our CTI License for Thermal Testing which was established earlierthis year.

McHale is a specialized engineering group providing high quality measurement andconsulting services in plant performance evaluations for cooling towers and BOP testing, audits, monitoring, and optimizationsas well. McHale is the industry leader in supplying cost effective solutions, professional and innovative staff, and quality

precision, calibrated equipment for your testing program.

McHale is the successor of the past Environmental Systems CorporationPerformance Services Division (formerly PGT) and has assumed many oftheir outstanding contracts and potential opportunities. McHale has purchased all of the ESC testing equipment, and technical and intellectuaassets, including the entire calibration facility, to supplement our testingservices capabilities. Our new 7000 sq. ft. facility inKnoxville is ready to calibrate and stage the equipmentneeded for all of your testing requirements.

The McHale cooling tower testing program is being lead

by Mr. Gene Culver. Gene has more than 27 years of experience working in the cooling tower industry, has been an active member of a number of CTI technicalcommittees, and is a highly skilled CTI test representative through his significant experience in providingdrift, plume, and thermal testing services.

Please note the following contact information and let us quote your next testing project:

McHale & Associates, Inc.

(Knoxville Offices) Thomas Wheelock, P.E. Gene Culver

6430 Baum Drive Director of Testing Services Sr. Engineer - Cooling Tower Services

Knoxville, TN 37919 [email protected] [email protected]. (856) 588-2654

Thermaland

Drift

condensers. CleanAir’s other five offices perform emissionstesting, and modeling of ESPs and SCRs for performance

optimization. CleanAir also rents or sells calibrated test

instrumentation for thermal performance and emissions testing.

The Powell, TN office can be reached at (800) 208-6162,

fax (865) 938-7569, or at www.cleanair.com. Their mailing

address is: 7936 Conner Rd., Powell, TN 37849

S e e a d v e r t i s e m e n t o n p a g e 4 1

S e e a d v e r t i s e m e n t o n p a g e 3 1

has had for years

with the Cooling

T e c h n o l o g y

Institute. The

Powell, Tennessee

office is focused

on performance

testing and cooling

tower thermal and

drift tests across a broad array of industries. Within the power

industry, the Plant Performance group routinely conducts

component tests including evaluations of gas turbines, steam

turbines, HRSGs, boilers, cooling towers and steam







Toby L. Daley, P.E.T Daley & Associates, Inc

AbstractThis paper will present the recent testing results of

counterflow film and splash type reduced fouling

fill configurations. It will present a comparison of

the relative performance of the fills. This recent test-

ing program provides a today’s performance per-

spective of the most commonly used fills of this

type.

IntroductionSince the introduction of Poly Vinyl Chloride (PVC)

counterflow film fills there has been a continuing

Fill Media TestedThe fill media that were tested represent a mix o

reduced fouling fills for various water quality ap

plications.

These are:

· FB20

· FC18

· SNCS

· AAFNCS

· RF20

· DF254

· Spaced Tile

A Performance Comparison of Counterflow Reduced Fouling Fills

effort to reduce the fouling characteristics in fouling potential ap-

plications. Physical characteristics of high efficiency film fills such

as close flute spacing, cross corrugation and cross stacking of

packs are all negatives when considering their use in fouling po-

tential applications.

Early applications of these high efficiency fill media in potential

fouling applications in the 1980’s were met with failure due to a lack

of understanding of its behavior in the environment. It was not

uncommon to hear stories of towers which routinely became plugged

after a short period of service. It became accepted to repack a tower

every so many years to maintain the As-New thermal performance.

Thus, the goal of designing a new reduced fouling fill media be-

came how to reduce the fouling potential while trying to maintain

the heat transfer characteristics of a high efficiency fill media. Asthese new generations of reduced fouling fills became available it

was apparent that this goal was not going to be easily achieved. In

most applications the solution to scheduled repacking of high effi-

ciency fill media was the installation of a reduced fouling fill media

with a substantial reduction in tower performance.

However, over the last 15 years fill manufacturers have continued

to reduce the fouling potential and increase the thermal efficiency.

There is a physical limit in achieving this combination that is very

dependent upon the quality of the circulating water, water treat-

ment and environment.

This paper will present the results of recent testing of some of the

most common types of these fills. Basic thermal capability compari-sons will then be performed to provide the user with an under-

standing of fill selection impact versus performance. It is not the

intent to provide water quality guidelines for applying the fills.

There have been several quality technical papers previously pre-

sented to the industry on this subject.

An additional fill is included that is not a PVC film fill but is a

Splash-Film fill known as “Tile Fill” which was created by Ceramic

Cooling Tower in the late 1940’s. This fill has also been classified as

a non-fouling fill.

The testing was performed at the SPX Cooling Technologies De-velopment Center over a period from 2002 thru 2005. The raw tesdata was provided by SPXCT and the author performed the datareduction and analysis using custom developed software whichincludes the Cooling Technology Institute (CTI) Merkel and Psy-chrometric methods.

The configuration of the test cell and testing protocol has been previously described in the CTI Technical Paper TP88-05 “Com- parative Evaluation of Counterflow Cooling Tower Fills”, authored

by Bob Fulkerson.

Fill ConfigurationThe following table presents the fill configuration for each fill tested

Fill Nozzle Type Nozzle Nominal Fill Spray HeightSpacing, Height

inches

FB20 NS5A X 12 26 X 36 4, 6, 8 Ft. 26" C/L branch to

top of fill

FC18 NS5A X 12 26 X 36 4, 6, 8 Ft. 26" C/L branch to

top of fill

SNCS NS5A X 12 26 X 36 1, 1.5, 2 M 26" C/L branch to

top of fill

AAFNCS NS5A X 12 26 X 36 1,1.5, 2, 2.5 M 26" C/L branch to

top of fill

RF20 NS5A X 12 26 X 36 1.5, 2, 2.5 M 26" C/L branch to

top of fill

DF254 NS5A X 12 26 X 36 2.5, 5, 7.5 Ft. 26" C/L branch to

top of fill

Spaced NS5A X 12 26 X 36 3.25, 6.0 Ft. 26" C/L branch

Tile top of fill

Data AnalysisThe data was received in text file format and converted to a spread-sheet format. Using the analysis software, written by the Author, aCTI Merkel KaV/L was then determined for each test L/G, fill typeand height. A multiple regression curve fit analysis was performedto determine the coefficients and the proper equation form to math

ematically represent the L/G and KaV/L relationship.

This same analysis process was performed for each fill velocity andwater loading or Q/A (gallons per minute per square foot of fill plan

Toby L. Daley, P.E.







area) to determine the fill static pressure equation form and coeffi-cients characteristics.

The resulting L/G vs. KaV/L characteristics and Velocity vs. StaticPressure for water loadings of Q/A = 4, 6, and 8 are presented incurve form in Appendix A. The equations and coefficients are con-sidered proprietary.

The L/G vs. KaV/L curves are presented for a hot water temperatureof 100 F.

The Velocity vs. Static Pressure curves are presented at .070 den-

sity (lb dry air/ft^3 mix).

Performance Comparison ModelsThe typical goal for a thermal selection is to determine the mostefficient and economical tower to satisfy a required thermal duty,horsepower, and space available. In clean water applications this isusually straight forward and involves a traditional high efficiencyfill. However, when an installation involves a water quality and/or environment which could interact with the fill and produce foulingthen fill selection process involves other considerations. Theseconsiderations might be hot water temperature, fill velocity, water loading per square foot, etc.

Thus, the need for thermal performance equivalence usually arises.

The following questions generally occur.

· If I leave the cell size and horsepower the same, what is the performance capability if I change to a different fill but keepthe same fill height? (Especially true in an existing tower.)

· If I change the cell size and the fill height, how much larger in plan area is required at the same horsepower?

There can be and usually are many more questions. The answer involves much more that just changing the fill selection. How doesit affect the air inlet heights, fan size, gear reducer, plenum, etc? It isnot the intent to provide these answers herein since there are varia-tions in proprietary rating systems and methodology. However, afill only performance comparison can be performed by using the fillthermal characteristics and static pressure curves.

The performance comparison models involved the following;

· Defining three thermal duties which utilize L/G’s boundingthe characteristic line. This included a varying approach,water loading, fill velocity for a WBT = 78 F.

· Creating a normalization process to reflect % change in ther-mal capability or % change in required plan area.

The following table shows the duties used to create the compari-sons.

Duty Range, F App, F Q/A

A 10.0 6.0 3.5

B 10.0 10.0 6.0

C 10.0 14.0 8.0

The normalization and comparative process consisted of the fol-lowing;

· A 4 Ft. fill height of FB20 was used as the base fill, plan area,and horsepower. All other fills were then compared to it.

· Holding the FB20 plan area constant – % of Capability wascompared.

· Holding the FB20 horsepower constant – Required % plan

area was compared on a normalized basis.

Fill velocities ranged from 300 to 700 feet per minute.

Performance ComparisonsThe results of the performance models are presented in two graphi-

cal forms. One for the capability comparison and second graph fo

the percent adjusted plan area comparison. Each graphical form is

plotted against nominal fill height in feet.

All comparison graphs are at HWT = 100 F.

The following graphs are presented in Appendix A:

Holding the FB20 plan area constant – % of Capability was com

pared.· Figure A1 Duty A R=10 F, A=6 F, Q/A = 3.5, WBT = 78 F

· Figure A2 Duty B R=10 F, A=10 F, Q/A = 6.0, WBT = 78 F

· Figure A3 Duty C R=10 F, A=14 F, Q/A = 8.0, WBT = 78 F

Holding the FB20 horsepower constant – Required % plan area

was compared on a normalized basis.

· Figure B1 Duty A R=10 F, A=6 F, Q/A = 3.5, WBT = 78 F

· Figure B2 Duty B R=10 F, A=10 F, Q/A = 6.0, WBT = 78 F

· Figure B3 Duty C R=10 F, A=14 F, Q/A = 8.0, WBT = 78 F

% of Capability Comparison - Example

Figure A-1 reflects that as compared to 4 Ft. of FB20 in the same fil

plan area it would require the following fill heights or greater to

achieve the 100% capability.

Fill Minimum Equivalent Fill Height – Duty A

FB20 4 Ft. (Base)

FC18 6 Ft.

SNCS 1.5 M

AAFNCS 1.5 M

RF20 1.5 M

DF254 5.25 Ft.

Spaced Tile 4 Ft. = - 35% capability (Not Shown)







Required % Plan Area Comparison – Example

Figure B-1 reflects that as compared to 4 Ft. of FB20 to maintain thesame horsepower would require the following change in plan areato achieve the 100% capability.

Fill Required Minimum Equivalent Fill Plan Area,Ft^2 at Same Hp – Duty A

FB20 4.0 Ft. (Base)

FC18 4 Ft. Requires 2.8% Increase

SNCS 1 M Requires 6.2% Increase

AAFNCS 1 M Requires 4.2% Increase

RF20 1 M Requires 4.2% Increase

DF254 4 Ft. Requires 2.8% Increase

Spaced Tile 4 Ft. Requires 52.1% Increase (Not Shown)

ConclusionsIn concluding it can be seen from the figures in Appendix A thereare several options that exist in fill selections classified as Reduced Fouling Fills. The continued efforts to improve the thermal charac-teristics of these types of fills have produced a varied selection tochoose from depending upon the quality of the circulating water and the environment. However, in general the more reduced foulingeffective the fill is there is a performance trade off due to the physi-cal characteristics required to achieve this goal.

APPENDIX A% of Capability Comparison

· Figure A1 Duty A R=10 F, A=6 F, Q/A = 3.5, WBT = 78 F

· Figure A2 Duty B R=10 F, A=10 F, Q/A = 6.0, WBT = 78 F

· Figure A3 Duty C R=10 F, A=14 F, Q/A = 8.0, WBT = 78 F

Required % Plan Area Comparison

· Figure B1 Duty A R=10 F, A=6 F, Q/A = 3.5, WBT = 78 F

· Figure B2 Duty B R=10 F, A=10 F, Q/A = 6.0, WBT = 78 F

· Figure B3 Duty C R=10 F, A=14 F, Q/A = 8.0, WBT = 78 F

% of Capability Comparison






% of Capabili ty Compar ison continued Required % Plan Area Compar ison




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Required % Plan Area Comparison cont’d

APPENDIX B

Fill Characteristic CurvesCurve No.1 FB20 4, 6, 8, Ft. Fill Heights

Curve No.5 FC18 4, 6, 8, Ft. Fill Heights

Curve No.9 SNCS 1, 1.5, 2 M Fill Heights

Curve No.13 AAFNCS 1, 1.5, 2, 2.5 M Fill Heights

Curve No.18 RF20 5, 6.5, 8 Ft. Fill HeightsCurve No.22 DF254 2.5, 5, 7.5 Ft. Fill Heights

Curve No.26 Spaced Tile 3.25, 6.0 Ft. Fill Heights

Fill Pressure Drop CurvesCurve No.2 FB20 4 Ft Fill Height Q/A = 4, 6, 8

Curve No.3 FB20 6 Ft Fill Height Q/A = 4, 6, 8

Curve No.4 FB20 8 Ft Fill Height Q/A = 4, 6, 8

Curve No.6 FC18 4 Ft Fill Height Q/A = 4, 6, 8



Curve No.10 SNCS 1 M Fill Height Q/A = 4, 6, 8

Curve No.11 SNCS 1.5 M Fill Height Q/A = 4, 6, 8

Curve No.12 SNCS 2 M Fill Height Q/A = 4, 6, 8

Curve No.14 AAFNCS 1 M Fill Height Q/A = 4, 6, 8Curve No.15 AAFNCS 1.5 M Fill Height Q/A = 4, 6, 8

Curve No.16 AAFNCS 2 M Fill Height Q/A = 4, 6, 8

Curve No.17 AAFNCS 2.5 M Fill Height Q/A = 4, 6, 8

Curve No.19 RF20 5 Ft Fill Height Q/A = 4, 6, 8

Curve No.20 RF20 6.5 Ft Fill Height Q/A = 4, 6, 8

Curve No.21 RF20 8 Ft Fill Height Q/A = 4, 6, 8

Curve No.23 DF254 2.5 Ft Fill Height Q/A = 4, 6, 8

Curve No.24 DF254 5 Ft Fill Height Q/A = 4, 6, 8

Curve No.25 DF254 7.5 Ft Fill Height Q/A = 4, 6, 8

Curve No.27 Spaced Tile 3.25 Ft Fill Height Q/A = 4, 6, 8

Curve No.28 Spaced Tile 6.0 Ft Fill Height Q/A = 4, 6, 8

















































David M. Suptic P.E. LLC

Abstract :Faced with multiple gear reducer

failures on two large cooling tow-

ers, an international power genera-

tion facility replaced 28 sets of rear

reduction drives and supporting

structure with new, upgraded equip-

ment. A description of the unique

nature of this large scale equipment

replacement project provides the

reader with several key steps to

ness, bolt hole locations, and details of the gear reducer loca-

tion relative to existing support beams. (Figure 1)

Large Scale Mechanical EquipmentReplacement - Simple Steps for Success

insure success on construction products of a similar nature.

Introduction:After less than two years of operation a new power genera-

tion facility located in western Turkey experienced a series

of cooling tower gear drive failures. The new cooling towers

were two large counterflow units, each with 14 cells of back

to back 10 Meter diameter fan drives. The cooling towers

provided heat removal for a four unit-1650 megawatt gas

fired cogeneration plant. The cooling towers were constructed

of pultruded fiberglass and circulated sea water for cooling.

Replacement of the failing gear drives was necessary to pre-

vent the loss of power generation capacity. Mechanical fail-

ures and replacements are not uncommon on large industrial

cooling towers, however, such replacements are usually per-

formed on one or two cells with limited plant impact. The

urgency of this particular replacement and the large number

of units to be replaced created the need to apply successful

project management and field construction techniques in an

environment of language and cultural diversity, to say the least!

The writer served as a technical advisor to the project man-

ager for the 28 cell mechanical equipment replacement project.

Background:The project was divided into three distinct phases; initial field

measurement and verification, trial installation, and final in-

stallation. Accurate field measurement of existing mechani-

cal support beams was considered critical to insure the proper

design and fabrication of new mechanical supports. Seven

months before actual equipment installation, the writer per-

formed field measurements of beam sizes, elevations, level-

Figure 1

The condition of the supporting wide flange beams was satis-

factory even though their material was galvanized steel, bu

there was considerable corrosion of the 10" square tube sup-

porting the old mechanical system. (Figure 2)

Figure 2

A trial installation of two gear reducers with torque tube type

supports was scheduled one month prior to final installation

While domestic projects of this type may not require this ex-

tra step, the logistics of shipping a large number of units across

the Atlantic Ocean made it more important to perform this

trial installation. A construction process could also be cre

ated that would be reviewed and approved by power plan

David M. Suptic













managers. The local workers would also have an opportunity

to learn the process of cooling tower construction before full

scale installation.

Final installation was planned for July 2005. Unfortunately

the weather during July in western Turkey is very hot, up to

40 degrees C (104 degrees F). This hot temperature would

impact the construction schedule but worker safety was very

important. The work crew consisted of 17 Turkish carpen-

ters and one construction foreman who was experienced with power plant construction. None of the workers spoke En-

glish or were able to read drawings. The foreman spoke

broken English and was able to instruct workers on the proper

cooling tower construction methods. Two plant engineers

assisted with communication and coordination with plant op-

erations personnel. The engineers spoke fluent English.

Two 50 Ton cranes were used in the final construction phase,

one at each cooling tower. The work crews were split evenly

between the two towers. Only one cell on each tower could

be shut down at a time to keep the plant on line. Work was

initially scheduled for 12 hours per day, six days per week.

The high heat forced the schedule be relaxed to nine hour

days. The project manager believed the total project could be

completed within 18 working days. A construction process

was needed that would produce a safe job with a minimum of

delays.

The Process:Since the gear reducer model and manufacturer were to be

changed, the support system design was also revised. The

new structural support and gear reducer would raise the fan

height by approximately 15.25 cm (6 inches). It was impor-

tant to verify the existing motor power wiring could be used

with the new mechanical system. Although the wire could

not be lengthened, the conduit system had enough play to

accommodate the additional equipment height. (Figure 3)

Figure 3

During the initial trial installation, the complete motor seg-

ment of the fan cylinder was to be removed. This work proved

to be very time consuming for the work crews to erect scaf-

folding and unbolt the segment. There was also concern for

the structural integrity of the remaining fan cylinder segments

So, for subsequent construction a large square opening would

be cut around the motor and support to allow removal of the

old torque tube assembly. (Figure 4)

Figure 4

This opening would later be resealed with the old segment

parts bolted together with fiberglass bands.

The area under the mechanical equipment was completely

covered with scaffold planks and surrounded with a guard

rail. With this level of fall protection in place, no climbing

harnesses were required by the workers as they worked in

the fan cell.

During trial installation, individual mechanical components

were removed and reinstalled by crane hoist. This process

was time consuming but helped the work crew learn how to

handle the mechanical components individually. Each old gear

reducer and fan hub was removed as an assembly and taken

to the plant’s machine shop where a torch, hub puller, and

hydraulic jack were used to separate the hub components

Figure (5)

Figure 5







The galvanized fan hub plates were reconditioned by sand-

blasting and painting with Urethane paint. Epoxy paint would

have been preferred but was not available. There was con-

siderable galvanic corrosion between the Aluminum fan blade

clamps, galvanized steel fan blade shanks, and the galvanized

hub. The use of Aluminum fan blade clamps for sea water duty

cooling towers is not generally recommended. Additional corro-

sion was also observed on the blade skin attachment bolts which

could lead to eventual blade failure. Correction of this deficiency

will be addressed in the future. (Figure 6).filling the gear reducer with oil, fabricating and installing the

fan shroud closure, rewiring the motor and checking rotation

direction, installing a new anti-rotation device to prevent back-

ward fan rotation, and finally clearing the cell of fall protec-

tion equipment, closing the access door, and operating the

fan.

The trial installation of two cells helped the work crew and

project managers fully understand the many steps that mus

be sequenced and performed properly to insure the best pos

sible installation. The new mechanical equipment operated

perfectly but the two trial installations had taken 36 workhours to complete with a crew of seven men.

Final Installation Project:26 new gear reducers, torque tube supports and associated

material arrived at the power plant in time for a project start

date of July 20. The construction process was closely re-

viewed for any potential time saving adjustments. Two

changes were proposed that would drastically reduce overal

time to complete each mechanical system change out.

First, the mechanical equipment would be preassembled on

the ground next to the cooling tower and the complete as-

sembly hoisted on to the tower. This process is used suc-

cessfully in the United States and with some rigging adjust

ments; the Turkish crew became comfortable with the hoist-

ing process. (Figure 8)

Figure 7

Figure 6

New split taper bushings were supplied to reinstall the fans,

and the steel center hub was sandblasted and repainted with

Urethane paint. The original fan assembly bolts were re-

used after careful cleaning. These stainless steel bolts were

torqued to appropriate values without bolt lubricant. As thetrial installation progressed the new torque tubes were set in

place. The position was measured to insure the fan would

be centered with the fan shroud. Hold down hole positions

were marked using the torque tube as a template. The torque

tube was removed with a crane hoist and new holes were

drilled in the existing support beams using a magnetic base

drill.

The torque tube was hoisted and bolted to the support beams.

Then the old motor, gear reducer, and drive shaft were rein-

stalled on the torque tube. The first drive shaft alignment

was performed by a senior millwright from the power plantstaff. Special steel adaptor rings for holding the dial indica-

tor were fabricated in the plant. (Figure 7 ).

Since the workers had little experience with cooling tower

construction it was very interesting observing the trial and

error process used to shim, bolt down, measure alignment,

and do again until correct alignment was achieved. Several

additional steps would be required to finish the installation

including, fan blade installation, oil and vent line installation,Figure 8







By hoisting the completed “power-pack” all the new gear

reducers could be pre mounted to the torque tubes at ground

level. The, as each old motor and drive shaft became avail-

able during the disassembly phase, the power pack assembly

could be completed including initial drive shaft alignment.

One key to success when replacing multiple sets of mechani-

cal equipment is to perform as much work as possible on the

ground. This is especially valid in hot weather because the

work is much more difficult inside the fan shroud with 100%cooling tower humidity surrounding the workers. Workers

inside the fan cell required frequent breaks to prevent heat

exhaustion.

Additional time saving steps were incorporated as the new

power packs were being installed in the fan cell. The power

pack was carefully positioned on the existing support beams

and then centered by measuring the radius from the fan hub

bushing flange to the inside surface of the shroud. By mea-

suring in four places the power pack assembly could be moved

and centered very accurately (within +/- 5 millimeters). (Fig-

ure 9). The hold down hole locations were marked using the

cause of the time required to sandblast, paint, and cure the

hub plates. Fortunately, the plant had two spare hub plates

that were cycled into the process. This ensured two com

pleted plates were available as soon as the rest of the fan hubreconditioning was complete. Fan blade shanks and alumi-

num blade clamps were cleaned up with emery cloth by the

work crew as slack time permitted.

The fiberglass shroud openings were cut with angle grinders

which made quick work of shaping the fiberglass parts to fit

Custom closures for holes in the old shroud were fabricated

by hand and shaped with the grinders too. Workers were

always careful to observe safety precautions when grinding

on the fan deck. Fire extinguishers and a fire hose were a

hand for any unexpected sparks.

It was very important for the work crew to coordinate ef-forts with the plant operation and maintenance personnel

Plant personnel coordinated and performed the fan hub re

furbishment and provided electricians to disconnect and re-

connect the motors and install new vibration switches. Lock

out/tag out of the fan motors was performed by plant engi-

neers when any motor was taken out of service or the new

cell was started up. The plant painter was required to apply

epoxy touch up paint to the torque tube and gear reducers

before they were put into service.

Before each new cell was put back into service the fan blade

pitch was adjusted to 10 1/2 degrees to achieve optimum moto

amperage. Adjusting the pitch was necessary because o

slightly different fan speed and the increased fan elevation

within the fan cylinder. Vibration on the fan shroud had in

creased, compared to original uncut stack, but remained within

acceptable levels.

Conclusion:The time required to deconstruct and reinstall each fan cel

was reduced from 16 -18 hours per cell to less than 12 hours

Figure 10

Figure 9

torque tube as a template. To save even more construction

time the power pack was hoisted and moved aside with the

motor sticking through the fan shroud access door. Holes

were drilled in the support beams and the power pack was

quickly moved back in place and bolted down tight. Drive

shafts were aligned to final tolerances after the power pack was bolted in place.

Another helpful time saver was to preassemble the stainless

steel oil lines and vent lines on the ground. All 26 units were

preassembled when workers had any slack time. They were

easily hoisted into place through the top of the fan shroud and

quickly connected to the power pack assembly. (Figure 10)

The turnaround time for removal and refurbishing the old fan

hubs became the bottleneck in the construction process be-






By Gene Ort, Internet Marketing JV

AbstractYou have a better chance of winning at roulette

than protecting your cooling towers with mechani-

cal vibration switches. The odds at roulette are

relatively straight forward. There are 36 numbers

with which you might win plus two sure-loss

“house numbers”: 0 & 00. If you play just num-

bers with a payoff of 35 to 1 for a win, long-term,

you probably lose 5.26% of your money. That’s

like a mortgage without the house.

The odds of protecting your cooling towers with

mechanical vibration switches from excessive vi-

bration are more difficult to calculate. But they

are so poor, precision isn’t necessary to make the point. It is tempting to para-phrase the old say-

It’s the old 80-20 rule but in reverse: 80% of the

switches handle 20% of the problems. The resof the time, they are clueless. Why do you

think we call them “earthquake switches”?

The Nature of the ProblemIn many plants, cooling towers are still consid

ered BOP (Balance of Plant) meaning they de-

serve less investment and attention than more

critical machines: a legacy from the times of

less plant efficiency and substantial excess

cooling capacity. Now, there is greater produc

tion efficiency and less capital spent on cool-

ing towers. Excess cooling capacity has dimin

ished. In many plants, if you lose a cooling

Roulette And Mechanical VibrationSwitches: What Are Your Odds?

ing, “Close only counts in horseshoes, hand grenades, and me-

chanical vibration switches”, but that does a disservice to horse-

shoes.

In many plants, cooling towers are no longer balance of plant (BOP)

equipment worthy of only “symbolic”, minimal, or lowest cost pro-

tection from excessive vibration. Losing a cell in the heat of sum-

mer can reduce production throughput. With their increasing sig-

nificance, cooling towers require better protection than afforded

by mechanical vibration switches. With any reasonable definition

of “protection”, a case will be made that mechanical vibration

switches, called “earthquake switches” in the trade, may offer no protection at all from the excessive vibration of the rotating equip-

ment in your cooling towers. Mechanical vibration switches do

sense shock. They sense vibration at very high levels or high rpm

and may give notice that a disastrous failure has just occurred.

Better solutions will be listed with pros and cons.

Introduction: It’s Your Choice- Effective Cooling Tower Protection

or Disaster Confirmation

Figure 1 is a greatly simplified nomograph based on physics and

the generally accepted values of the condition of rotating equip-

ment. It represents the accumulated knowledge of decades of the

vibration instrumentation industry. It is developed in detail at the

paper’s end (see figs. 1a-1d). In log scale and at a typical 1 Gacceleration switch setting at 1800 rpm driver speed, the sensitiv-

ity area for mechanical vibration switches in Fig. 1 begins at over

4 times the level designated as “BAD”: at the lower fan speeds, it

is over 20 times!

The 80-20 Rule for Earthquake SwitchesWith any reasonable definition of “protection”, a case can be made

that mechanical vibration switches, derisively called “earthquake

switches” in the trade, offer little or no protection for rotating

equipment from excessive vibration in cooling towers.

Fig. 1

tower in the heat of summer, cooling capacity drops below 100%

production is decreased and cooling towers are Not BOP Anymore

If plant managers and underwriters do not know, vibration analystsdo know that cooling towers present a particularly challenging situ

ation for monitoring its vibration. The train includes an electric

motor drive, usually at 1800 rpm, long jack-shaft, right angle speed

reduction gearbox to approximately 100 to 300 rpm, and large diam

eter fans (fig. 2). This machine is large, complex, production depen

Gene Ort

Fig. 2







dant and may be the last machine in your plant on which you want

a mechanical vibration switch. But 15,000 to 20,000 mechanical

vibration switches go into service every year: most on cooling tow-

ers.

The Scope of the ProblemThere could be over a quarter-million mechanical vibration switches

out there. There are three major manufacturers of mechanical vibra-

tion switches which are typically sold to cooling tower manufactur-

ers (OEMs) in substantial volume. One switch manufacturer claimed on their web site that 125,000 switches have been installed. There

are likely over 15-20,000 new switches going into service every

year. In addition, there is also a switch that uses a pedestal and ball

with a chain to a switch. If the tower shakes enough, the ball falls

off the pedestal to initiate the switch action, to be reset by hand.

TerminologyIn the development of figure 1 and the basic vibration information

that follows, four terms are used:

1. frequency (in cpm= cycles per minute or RPM = cycles at

running speed)

2. acceleration (in Gs)

3. velocity (in ips = inches per second)

4. displacement (in mils peak to peak)

They refer to the movement of points on the machine and are re-

lated by physics. Given frequency and one point, the other two can

be calculated and shown on the graph.

Accepted Use of These TermsBy their design, mechanical vibration switches are sensitive to ac-

celeration only. There is no signal from which to generate more

meaningful information about a machine’s operating condition and

generate meaningful alarm levels.

Electronic switches and monitors use an accelerometer to produce

a “dynamic signal” containing all the significant contributors of interest. This signal can be used with instrumentation to:

1. Develop overall vibration (not shock values)

a. In terms of acceleration

b. Be integrated to show overall vibration in velocity

c. Be integrated again to show overall vibration in

displacement (not recommended)

2. Use the “waveform” (complex signal) for analysis

3. Develop spectra of the various contributors to vibration

for analysis.

Debunking Eight MythsBy misusing the terminology above, some myths developed over

the years about the design, suitability for the purpose and accuracy

of mechanical vibration switches, especially as they relate to cool-

ing tower protection.

Myth #1- Use acceleration, not velocity or d isplacement

To place mechanical vibration switches as solutions for monitoring

cooling towers, vendor’s marketing “promotes” the term accelera-

tion over the other, more relevant terms used for that purpose.

Examples:

1. Acceleration is your best solution for monitoring cooling

towers

2. Displacement is for deformation or bending (inferring no

machine vibration)

3. Velocity is most useful for sound (again, inferring not ma

chine vibration)

Fact: Velocity and displacement are used to monitor vibration in

the overwhelming majority of rotating equipment in the world. The

claims of mechanical vibration switch vendors fly in the face of alaccepted practice of vibration monitoring whether for protection or

analysis; for cooling towers or most of the other machines in the

world. Remember, acceleration is all that these vendors have.

Myth #2- Design & Suitabili ty for Purpose

Claims are made that a mechanical vibration switch is effective for

“slow to medium speed machines”, or “0 to 3600 rpm”. (Right of the

website)

Fact: “It depends on what the definition of is is.” It depends more

on what the definition of effective is. Take a quick look at Figure 1

again. That claim is simply not true for vibration or any reasonable

definition of effective.

Myth #3- Acceleration is KINGReference by proponents is made to Newton’s Law F=MA. In

context, it is meant to leave the impression that acceleration is

essential and by their absence that displacement & velocity are

not. F=MA is appropriate if you want to launch your cooling tower

and occasionally they do; likely with their mechanical vibration

switch.

Myth #4- Unique Terminology used for MechanicalVibration Switches

Terms are used by proponents of mechanical vibration switches

such as “acceleratory vibration” and “acceleratory shock”. This

looks and sounds good: highly technical.

Fact: An Internet search for acceleratory vibration” brings up one

page and it’s the vendor’s. When is the last time you got a one

page hit for any search? “Acceleratory shock” gets 20 hits, but al

related to sites promoting mechanical vibration switches with no

other reference in the world of internet searches.

Myth #5- Set Point Accuracy

Some manufacturers claim accuracy of set point adjustment.

Fact: These are very crude devices. Do you know how to check to

see if the switch is set for 1 G? Pick it up and rotate the switch 90°

(on its side). If you hear the mechanism “click”, you’re set fo

approximately 1 G. If you can rotate the switch 180° (upside down)

before you hear the “click”, the switch is set for approximately 2 GsNote there was no vibration involved.

Further, this is likely how production sets the unit prior to ship

ping to the OEM or end user since it is quick and less costly than

setting the units on the huge shakers necessary for the switches

large mass. You can also get the “click” if you hit it hard enough

with a big enough hammer. In real life, if the cooling tower ha

substantial shock or “bump” on startup and the switch activates

the solution is to “crank it up” until “it doesn’t bother you” any-

more. That higher setting is unknown and likely quite high, furthe

limiting the switch sensitivity in the cooling tower vibration levels

of interest.







Myth #6- Range Accuracy

In most instrumentation, you match the instrument range to ex-

pected values in operation preferring not to operate too near the

bottom or top of the range. Some mechanical vibration switch

product lines show multiple ranges leaving it up to you to draw

whatever conclusions you wish about the accuracy and suitability

for your use. It’s not clear how one chooses between 2, 4.5, 5, or 10

g models.

Fact: It is likely that all the mechanisms of one manufacture are the

same but different ranges are claimed. Inquiry of your vendor isappropriate. If it is true in your case, the 2 G switch you bought

thinking you have “narrower range with finer adjustment” is really

as course as a 10 G switch.

Myth #7- Cost

Legacy issues include the perception that mechanical vibration

switches are cheap and do the job.

Fact: There are some cheap switches available in the $200-$300

range. Prices off the Internet can go from $200 to over $700 for

some models. But if they are unsuitable to protect your cooling

towers, any price is too high. For similar prices, there are much

better solutions available.

The OEMs that buy mechanical vibration switches in quantity, do

buy for substantially less unit cost. It’s up to the user to specify

better solutions and possibly pay a little more for better protection

of this valuable plant asset.

What is the cost of lost production? What does it cost to replace

a gearbox or repair the damage to the cell if the fan throws a blade?

Or worse? Is saving just one of those disasters worth $200 to

$500?

Very Basic Applied VibrationVibration is a symptom of underlying machine component condi-

tion and the overall function of the machine. To better understand

the statements of this paper and the claims of mechanical vibrationswitch manufacturers, only the basics of vibration needs to be

understood; essential to make your own informed judgment. The

following analogies support this abbreviated vibration primer:

Analogies: Overall Values vs. Complex

Light

We think of light in overall terms as intense, bright, soft, or dim.

We’ve all been fascinated as kids to find that sunlight separates

into its different colors (frequencies) by use of a prism or as an

explanation for what makes a rainbow.

Sound

We know that the sound we hear can be thought of as loud or faintand yet it too is complex. Submariners can tell the class and name

of Russian submarines from their complex and unique “signatures”.

Even without the fancy instrumentation, humans are wonderful

sound analyzers. A song no sooner starts and you know if it Bing

or Sting, Minnelli or Bocelli. Your phone rings, you answer, and

within two words, you know it’s your wife and whether or not you

are in trouble.

Vibration

Overall vibration levels can be high or low, but like sound and light,

are very complex. Basic machine vibration is made up of a variety

of vibrations contributed by the machine components, its mount-

ing, blade aerodynamics, and other process & environmental fac-

tors. In the case of cooling towers, the overall vibration, high o

low, is comprised of the summation of all vibration contributions a

varying frequencies and amplitudes from:

1. the electric motor drive

a. mechanical imbalance, electrical imbalance, misalignment

bearing frequencies, soft motor mounting and more; a func

tion of driver RPM.

2. the gearbox

a. mechanical imbalance, misalignment, bearing frequencies

and gear mesh frequencies; a function of driver RPM and

fan RPM.

3. the fan

a. mechanical imbalance, misalignment, and aerodynamic con

tributions; a function of fan RPM, the number of blades and

other factors.

4. Other cells (propagation) and the environment (such as trains

going by in close proximity)

The most destructive energy on any machine is imbalance andmisalignment. Their energy level at frequencies of one or two times

running speed is so large a part of overall vibration, it usually

masks the other higher frequency contributions depending upon

where the measurement is taken and for what purpose. Overal

vibration is measured by the electronic vibration switch and is

most effected by imbalance and misalignment. Only your analys

can give you the details of the condition of the machine by estab

lishing baselines and watching over time to see how the various

frequencies change. Your GP may tell you if you are in good health

or not, but you wouldn’t go into open heart surgery without a

cardiologist and at least results from your electrocardiogram.

Likely causes of vibration in coo ling towersIn cooling towers, there are many contributors to vibration bu

likely causes of vibration include:

1. Plugging weep holes in a fan blade is a source of grea

imbalance as condensate builds within only one of sev-

eral blades.

2. The aerodynamic performance of the fan blades can be

significant. One reported case had blades getting a lift as

they passed over the jackshaft. That would show us a

significant imbalance at a frequency equal to the number

of blades times running speed.

3. Misalignment of motor to gearbox at the end of the long

jackshaft can be significant at one or two times runningspeed.

4. Gearboxes in early stages of degradation offer dramatic

dynamic signals but show little effect on overall vibration

readings. In later stages, their contribution to overall vi

bration gets significant.

5. The same can be said of rolling element bearings in the

gearbox or motor. An interesting side note to this is tha

rolling element bearings often appear to get “better” jus

before complete failure.












This is not protection 24/7 but a complement to an

installed vibration switch.

2. Electronic vibration switch mounted on the gearbox

3. Vibration transmitter mounted on the gearbox

4. Single channel monitor mounted outside the cell using an

accelerometer on the gearbox.

5. Dual path monitor using a single installed accelerometer

6. A multi-channel monitor with single or double accelerom-

eters installed per machine train.

Alternatives 2 through 6 offer a substantially superior solution

for protecting cooling towers than do mechanical vibration

switches. They share one thing in common: they use an acceler-

ometer and electronic circuitry to capture the relative dynamic vi-

bration signal and process it to meaningful & useful overall vibra-

tion levels or for analysis when needed.

The electronic switch uses an internal accelerometer and is installed

as a unit. The monitor solutions use external accelerometers mounted

on the gearbox with instrumentation outside the cell.

Are there advantages of electronic switches over mechanical vi-

brations switches? Yes. As standard or optional features, you get:

1. Accurate sensing of the vibration found in the rotatingequipment in cooling towers

2. More precise and relevant alarm and shutdown set-point

adjustability

3. Adjustable time delay to ride through transient events

eliminating the need to run at set points higher than those

needed for prudent protection levels

4. Smaller size that is more appropriate for mounting on the

gearbox directly

5. Easy access to the dynamic signal needed for analysis

and quicker turn around on repairs

6. Valuable cooling tower information to trend and display

on your DCS operator interface.

Important Notes:a. REPLACEMENT OF MVS: If you are going to replace a

mechanical vibration switch, do not remove or disconnect

it before your alternative solution is installed and opera-

tional.

b. LEAVE THE MVS INSTALLED: Consider leaving the me-

chanical vibration switch installed in a “belt and suspend-

ers” approach to protecting a cooling tower: you have

already paid for it. Mechanical switches do sense shock

whereas electronic vibration switches sense vibration and

should have adjustable 3 to 5 second time delays built in

to override short-term episodes. Failure of some compo-nent might occur without vibration being a precursor.

c. MOUNTING A VIBRATION SWITCH: As seen in figure

8, both mechanical and electronic vibration switches can

be mounted in a poor or totally ineffective position. This

electronic switch is mounted on an extension of the

structure’s frame. Its axis of sensitivity is parallel to the

jack shaft with its mounting negating most if not all the

benefits of the electronic vibration switch. Consult some-

one who knows this application about the mounting of

your current switch or its replacement. If you like, attach

a digital image of the switch installation to an e-mail and

send it to me at [email protected] for comment.

would be glad to help.

d. SET POINT FOR ALARM OR SHUTDOWN: How do

operators know what cooling tower vibration levels are

normal or tolerable and what levels are dangerous? Tha

is a good question. It is addressed in general terms on the

nomograph overlays of “Good” to “Bad”. See fig. 1C

There is no one answer but 0.5 ips velocity is high in most

applications. But this is only a reference and not a rec

ommendation for any specific machine. Of the many callI have received over the years with this question, I ask“What does your vibration analyst say?” The answer altoo often is, “I don’t know. I didn’t ask.” Check with youanalyst or if you use a contract analyst, ask them. Theyare a good source of this information. The reason is thait is important to know the baseline levels, current levelsand performance of the cooling tower in the past. It de

pends on the vibration sensing device, where it is mountedhow it is mounted and your analyst can answer with thatin mind. Often, the levels are “negotiated” between operations and maintenance for practical plant/machine re-lated issues.

Some application issues for each electronic vibra-tion switch solution include:

1. Mounting an accelerometer on gearbox (see fig. 7)

Using an accelerometer and running the cable to a box

outside the cell is a partial solution. In itself, it is no

installed “protection” but is used by many to manually

monitor a tower periodically. It gets the dynamic vibra

tion signal into an area more easily and safely accessed by an analyst collecting the data for long-term trending o

trouble shooting. It is data you should get regardless o

your protection solution. If done well, it will complemen

vibration switches by giving early warning of problems

and likely pin-point the source for quicker repairs. If it i

already installed, install an electronic vibration switch for

the 24/7 protection of the machine as soon as possible.

2. Electronic vibration switch mounted on the gearbox

This is a common replacement tactic offering the advan-

tages of an internal accelerometer, relatively moderate cost

Figure 8







but if replacing a mechanical vibration switch, requires

power be run to the unit and with some added cost. If the

switch is mounted on the gearbox, it still leaves the ques-

tion of getting that important dynamic signal out to the

vibration specialist.

ADVANCED NOTICE: By the time this paper is distrib-

uted, there will be on the market (or soon to be on the

market) an inexpensive two-wire electronic switch de-

signed specifically to replace mechanical vibration switches

without the sometimes high cost of running added power lines to new powered electronic vibration switches. Just

pull the mechanical switch and install the electronic switch.

It will run off of the same line and you get all the benefits

of an electronic switch.

3. Vibration transmitter mounted on the gearbox

While not common in use on cooling towers, a vibration

transmitter mounted on the gearbox, can be used in con-

junction with a PLC or DCS trending the 4-20mA signal

and giving relay action based on preset alarm and shut-

down levels. Some offer 4-20 mA signal and the dynamic

signal which can be run to a box with a BNC jack for the

analyst although the full range of frequencies for appro-

priate analysis may not be available to the analyst. Cau-

tion is suggested.

4. Single channel monitor mounted outside the cell

Using an existing installed accelerometer or install one

and add a single channel monitor outside the cell. Make

sure the dynamic signal is available for the vibration ana-

lyst. Note the terminology in the industry: A single chan-

nel monitor may be called an electronic vibration switch

with a remote accelerometer. The terms are interchange-

able. The device does the same job.

5. Dual path monitor

This is a solution using a single installed accelerometer

to a monitor that splits the signal and processes it for

both velocity (for the driver speed) and displacement

(for the low speed fan). At 1800 rpm, velocity is the best

choice. For 100 to 600 rpm, displacement is a better

choice. The problem with this solution is that the signal

from the accelerometer is integrated once to get velocity

which is standard industry practice. Double integration

of the signal is required to get displacement and this

gives signals with high noise to signal ratios. This can

be problematic so caution is advised. Worst case: if

tried and problems arise, you can ignore displacement

and still have a full functioning electronic vibration

switch with all of the advantages over mechanicalvibration switches.

6. Multi-channel monitor

Given that multiple cooling tower cells are in a common

structure, there can be advantage to running the signals

from installed accelerometers to a common instrument for

processing. This depends on a comparison of total in-

stalled costs.

Some Notes About Vendors

There are many vendors of electronic vibration switches with good

products that will outperform mechanical vibration switches. Those

who supply both may have compromised their credibility in the

manner in which they market their mechanical offerings. That judg

ment is yours to make. You are welcomed to contact me a

[email protected] or call my cell at 979-739-7279 to find ou

more about products and services available to meet your cooling

tower monitoring needs.

Bio: Gene Ort is a thirty year resident of southeast Texas with amechanical engineering degree & holds two patents. Employmen

history includes working for a major gas turbine and AC motor

manufacturer, and major manufacturers of instrumentation for vi-

bration monitoring of rotating equipment including cooling towers

He has had the training for vibration analyst. Gene successfully

led a project that outfitted an entire grassroots refinery in Thailand

with all of the installed vibration monitoring instrumentation as

well as the portable vibration data-loggers and analysis software

He has spoken to many audiences interested in the protection of

rotating equipment including the Saudi Arabian Chapter of the Vi

bration Institute.

Vibration Nomograph SimplifiedThe “vibration nomograph” referred to in figure 1 at the papers

beginning, is a standard representation of the relationship among

frequency, acceleration, velocity and displacement. It is based

upon physics and I have used it since the early seventies. It is

used in vibration analysis courses as well as by most vibration

instrument manufacturers for the practical application of their prod-

ucts. The only arbitrary data shown are the superimposed lines

labeled from “Good” to “Bad”. This represents the accumulated

knowledge and consensus of what constitutes acceptable vibra-

tion levels for most machines. Example of the conservative nature

of these values. “Bad” is over 0.5 inches/second (ips) velocity.

For the purpose of this paper and its relatively narrower scope, thegraph is simplified in steps illustrated in figures 1a through 1d tha

follow. If you are familiar with the subject, reading further on is no

necessary. If you are not familiar with the subject, it does not take

great study to see the logic of the argument.

Co n t i n u e d o n p a g e 5 6







Fig. 1a is the nomograph with all the lines designating :

· Frequency in terms of machine speed (vertical)

· velocity (horizontal)

· displacement (diagonal bottom left to upper right)

· acceleration (diagonal bottom right to upper left)

This is a complex graph, log based, and difficult to use for novices:

simplification is in order.

Fig. 1b is the “ skeleton” of the nomographThis shows only the lines for frequency, displacement, velocity

and acceleration of interest for cooling tower rotating equipment

Fig. 1a

Figure 1b

Co n t i n u e d o n p a g e 5 8







Fig. 1c shows the superimposed values of Good to BadThese are the commonly accepted vibration levels for machines

running at various speeds.

Figure 1c

Fig. 1d is fi gure 1 at the paper’s beginning with the 1 Glevel added for reference

Greatly simplified, it assumes likely set-points for mechanical vibra-tion switches at 1 G (though likely higher), cooling tower drive at1800 rpm, and accepted vibration levels of a cooling tower.







IntroductionHistorically, water systems in industry have not

received the same attention as process systems.

Until a problem or failure occurred, water sys-

tems were typically considered a cost center

whereas the process systems were a profit

center. As a result, many water systems

evolved into applications that in today’s stan-

dards would not be considered a viable option

for new construction. One such system exists

at DuPont Sabine in Orange, Texas. The pur-

built and different heat transfer metallurgies

were introduced, the need for better quality

water became apparent. A pond system was

developed for additional cooling. It consisted

of a 500,000,000 gallon natural bottom pond

for cooling; a water distribution and return sys-

tem, with entry into the pond system well away

from the pumping station (Figure 1.0). Water

was taken from the Sabine River about 30 miles

upstream from the plant. The water was sup-

plied to the plant-site via the Sabine River Au

Improving Localized Corrosion in aComplex Cooling Water System

Michael H. Dorsey, E.I. DuPont de Nemours & Co.Kevin Daigle, ChemTreat, Inc.A.F. Brunn

pose of this paper is to document how this large, multifunc-tional, cooling water system has been revised to meet the

plant cooling requirements while maintaining acceptable cor-

rosion and deposition control.

BackgroundThe first production units at DuPont’s Sabine River Works

were placed into operation in the mid-1940’s. Although none

of the original production units are still operational, the basic

cooling water system that developed over time remains one

of the primary sources of heat removal at the site. Initially,

water was taken from Adams Bayou, adjacent to the plant,

and circulated once through for production areas in the complex. The plant is about 30 miles upriver from the Gulf of

Mexico and during times of dry weather Adams Bayou was

subject to chloride intrusion. As new production units were

thority (SRA) canal system and not subject to chloride intru-

sion. Supply water temperature was achieved by surface

evaporation in the pond plus enough water was discharged

from the pond and replenished with cooler SRA water. In

reality the system was just slightly better than once through

The site currently has nearly a dozen different operating ar-

eas with an extremely complex site cooling water system.

After the mid-1960’s new production units installed their own

recirculating cooling tower systems for process cooling since

the existing systems had reached their full heat rejection ca

pacity.

During the late 1980’s and early 1990’s there was a strong

push to lower the amount of water discharged to the river

The two most obvious high flow sources were the once

through water and the discharge from the pond system. From

the various options available, it was decided to enclose the

pond circulating water system and eliminate the once through

water from Adams Bayou.

Operation ConditionsThe current system circulates between 100,000 and 130,000 gpm

Fluctuations in flow are due to varying heat loads in the dif-

ferent process units and to some degree seasonal changes

Since radiation from the pond would no longer provide the

necessary supply water temperature to the process units, a

125,000 gpm cooling tower with a 25OF temperature differ-

ential was erected at the edge of the pond. Return water

from the plant is pumped across the cooling tower and dis-

charged directly into the pond. Suction for the site closed

cooling water system is taken at a point about 200 yards from

the cooling tower (west loop) and a second pumping station

about 400 yards from the pumping station (east loop). The

system is supplied by 65,000 gpm off the East lift station and

Michael H. Dorsey

Figure 1.0 – DuPont Sabine Site ClosedCooling Water System







35,000 gpm from the West lift station. Return water from the

west side of the plant (about 70,000 gpm at this time) crosses

the cooling tower; return water from the east side of the

plant (about 30,000 gpm) is sent through a ditch system to the

far southwest end of the pond system to obtain maximum

natural cooling.

Return water to the cooling tower from the west side of the

plant was directed through a wood lined ditch system that

existed in the past and discharged into the river. In fact, theentire wood lined ditch return was re-directed to the cooling

tower. This included demineralizer regenerant waste, filter

backwash, boiler blowdown, cooling tower blowdown, pro-

duction area washdown water, rain water runoff from the

site production areas, runoff from the site parking lot, some

runoff from the state highway in front of the site, and even

the runoff from the company golf course across the road

from the plant. All of this water was returned to the site

closed cooling water system across the cooling tower.

Initially, it was thought that the golf course and runoff from

the roadway was a major contributor to many of the prob-

lems seen in the site cooling water system. Analyses taken

for some time after this was discovered have never shown a

significant contribution of contamination.

Cooling water is used for a wide variety of process heat re-

duction methods from jacket cooling of high pressure extrud-

ers to in-column, direct cooling of process gases to standard

heat exchangers. There is a wide variety of metallurgy in the

system, from carbon steel and copper bearing metals to a

significant number of various stainless steels.

Before the cooling tower was installed and the system closed,

treatment consisted of chlorination of the circulating water at

the pump suctions. Target control was approximately 1 mg/

l free chlorine, but the capacity of the chlorination system

could not always achieve this residual. Lack of attention to

the chlorine feed system was also a factor in the overall op-

eration of this system. This continued into the initial stages of

the system being closed. Although there is no historical data,

it has been reported that corrosion rates on carbon steel were

in the 20 to 30 mils per year range.

Chemical Treatment HistoryWhen the cooling tower started up in late 1994 the once

through river water circulating system was integrated into

the pond system, the Adam’s Bayou water abandoned, and

the discharge to the river significantly reduced. Makeup to

the system was untreated SRA water, a low hardness, low

alkalinity, low silica, low solids water. However, during high

rain periods the organic content and suspended solids content

of the raw water increases dramatically. The system appar-

ently operated without too many problems for the first two

years although there is a lack of historical data to totally sup-

port that supposition. During periods of high organic intru-

sions, generally in the late fall and winter, it was impossible to

maintain a free chlorine residual in the system.

In early 1996 there was a perception that corrosion in the

system was increasing. Corrosion coupon racks (Figure 2.0

were set up in a number of operating areas and the results

were, at best, very poor. Carbon steel corrosion rates on 30

Figure 2.0 – Typical Corrosion Rack

day coupons of 20 to 40 mpy were not uncommon and up to

80 mpy was recorded. There was a significant pitting prob

lem on the unheated coupons as well. A review of the sys-

tem showed the chlorine feed to satisfy the demand was high

enough to drop the pH of the system water well under neu-

tral, sometimes below pH 5. A caustic feed system was in

stalled to overcome the pH suppression and increase alkalin-

ity on both the east and west loops in the fall of 1999. ORP

control of chlorine feed and pH control of caustic feed was

initiated at this time. Although chlorine feed is controlled by

ORP on the supply water downstream of the injection pointwater being returned to the ditch system is regularly checked

for free chlorine. These changes brought the pH back under

control and increased the almost negligible alkalinity back into

a somewhat reasonable range.

Corrosion rates, although much lower, still remained wel

above the target 5 mpy on carbon steel (Figure 3.0). Even

Figure 3.0 - Corrosion Rates (mpy)




with the lower corrosion rates, the pitting of

carbon steel continued at a higher than desir-

able rate. In addition, under deposit corrosion

on 304L and 316L stainless steel tubing oc-

curred in a number of exchangers resulting in

equipment failure and unplanned production

area shutdowns.

Other 304L and 316L stainless exchangers have

operated without significant problems since thecooling water system was closed in 1994. Stain-

less steel corrosion coupons in the system gener-

ally showed excellent corrosion rates, usually less

than 0.01 mpy and little to no pitting on the cou-

pons, although there has been an occasional cou-

pon that did show pitting and indication of mi-

crobiologically influenced corrosion (MIC). The

failed tubing was replaced and inspected for pos-

sible feeling that MIC had been the cause of the

tubing failures. Some analyses of deposits from

the failed tubes showed the presence of manga-

nese and there has never been a consensus as to

the exact cause of the failures.In early 2000 a program was established to

determine microbiological activity both by as-

sessing the sessile and planktonic bacteria

counts in various locations served by the

closed cooling water system. In general,

counts of both were very low when chlorina-

tion was maintained properly. These counts

ran between 102 and 104 with averages around

103. There has been an inherent problem with

the chlorination in the summer months. There

have been many times when the demand ex-ceeds the capacity of the chlorine delivery

system to provide sufficient chlorine to main-

tain the desired residual. This situation is be-

ing addressed with a proposed project to in-

crease the pressure of the motive water by

adding booster pumps in the chlorination educ-

tion system.

The plant also started a formal chemical treat-

ment program is early 2000. Because of en-vironmental concerns, several treatment chemistries were not

considered an option. Use of zinc as a cationic inhibitor was

recommended, but site environmental concerns precluded theuse of zinc until all other avenues were investigated. Using

water from the pond system, laboratory spinner bath studies

were performed to determine which treatment program would

provide the best return for the chemical investment.

The initial program consisted of an ortho phosphate, organic

phosphate, and a dispersant (Figure 4.0). It took nearly two

months for the system to stabilize because of its large size

and mud bottom in the pond. In June of 2000, sodium

hexametaphosphate was added to the system to evaluate the

benefits of polyphosphate. In July, 2001, due to a pH of ove

8.0 and sometimes approaching 8.5, the oxidizing biocide treat-

ment was modified to include a bromine component. The

addition of bromide was justified based on the high system

pH. Tripol yp ot as si um phos ph at e fe ed repl ac ed the

hexametaphosphate in an attempt to reduce reversion to or-

thophosphate and maintain a higher polyphosphate residual in

the system. Treatment modifications each resulted in sligh

improvement of carbon steel corrosion rates, but the success

was always questionable due to inconsistencies in the newer




corrosion data. Later review of the data indicated that some

of the flucuations could have been the result of seasonal

changes that impact the system. However, there are even

some inconsistencies with that assumption. Figure 4.0 pro-

vides a timetable of the treatment chemistries used in various

trials at the site. It does not include chlorine and caustic

since they have continuously been used.

Even when corrosion rates were lowered, the pitting rate on

carbon steel remained at an unacceptable high level.

would not exceed the zinc limitations at the outfall. It was

anticipated that there would be some insoluble zinc in the

system which proved to be correct. Curves had been devel

oped by the water treatment supplier to show a direct rela-

tionship between zinc concentration, orthophosphate concen-

tration, and pH. This data indicated that the best pH range

for operation without excessive zinc precipitation would be in

the range of 7.5 or under. There have been some periods

when insoluble zinc residuals were higher than normal, bu

generally these are periods are when the pH in the system is

somewhat high.

Zinc residuals have been closer to 0.2 – 0.3 ppm, but as can

be seen from Figure 5.0 corrosion rates have improved. Or-

thophosphate has been controlled between 5 to 7 ppm. The

pH has been a little harder to control. Although the tota

alkalinity was lowered from about 70 ppm to 20 to 30 ppm

the summer months saw pH increases from during dayligh

hours of 1.0 to 1.5 units. The automatic pH system cut the

caustic feed off when the pH increased above the set point

Figure 4.0 – Timetable of Treatment Chemistries

Numerous studies were conducted in the laboratory in an

effort to get a better handle on the microbiological compo-

nent in the overall problem. Various on-line, real time analyz-

ers were studied to determine if the claims that they could

predict microbiological fouling were overstated. Although in

some cases there were somewhat positive results the overall

result was not as definitive as we had hoped. The results of

these tests have been reported elsewhere.

In 2005 it was decided to review the possible use of zinc as a

cathodic inhibitor into the system. The environmental con-

cerns were overcome by agreeing that zinc concentrations in

the outfall would be held well below the allowable limits as

established by the NPDES permit. There was concern that

the mud bottom of the pond would adsorb a great deal of the

zinc, but the decision was made to give the program a try and

evaluate the results. The program would be initiated in four

steps. First, zinc would be added to the system and with

remaining controls held in place. Next the pH would be re-

duced to 7.5 to maintain solubility of zinc, and then the bro-mine component would be eliminated since the pH would be

lowered to a range where bromine did not improve the effec-

tiveness of the oxidizing biocide program. Finally, the chlo-

rine injection points would be changed with the addition of

higher motive pressure for chlorine induction and the ability

to inject the chlorine solution into a pressurized line.

Zinc feed was initiated in mid-January, 2005. The control

range for soluble zinc was targeted to be 0.5 to 0.75 ppm and

Figure 5.0 – Corrosion Rate Improvements (mpy)

but the pH continued to rise during daylight. Based on expe-

rience from other DuPont sites, we attribute this to algae

activity during the hot, sunny days that feeds on free carbon

dioxide in the circulating water. Addition of sulfuric acid i

being considered and would be used during these periods to

control the pH below 7.5. Table 1.0 shows this data.

Figure 6 provides a wider look at corrosion rates. This figure

shows corrosion rates at the same four locations since 1998Corrosion rates have decreased based on corrosion coupon

data.

The plant has now had nearly a year of service on the zinc/

polyphosphate/quad polymer program and the average cor-

rosion rate remains approximately 5-9 mpy with periodic in-

creases at individual units. Pitting can still be seen on the

carbon steel coupons, but it is also significantly less than was

found previously.




It will take a much longer period to determine if the MIC

problems have also been alleviated. In 2000, additional local

treatment for several production areas containing the 304 stain-

less steel reactor tubes was initiated. This supplemental treat-

ment included sodium hypochlorite to be sure there is always

controlled free chlorine residual in that production area. The

stainless steel reactor tubes have been again repaired be-

cause of leaks occurring in 2004 and only time will tell whether

this situation is also under control.

SummaryThere are times when people have questioned the continued

viability of this system. There have been many, some expen-

sive, problems with this system. We continue to look at cost

effective improvements that can be made to reduce these

problems as they develop. However, the goal of reducing the

environmental problems that the plant experienced during the

pre-1995 days has been met.

This system is complex and expensive to treat with chemi-

cals. It requires a substantial amount of operator, technical,

and management time to be sure the system is controlled very closely. Faced with the reality of having a large, com-

plex system with many of its shortcomings not recognized in

Figure 6.0 – Histor ical Corrosion Coupon Data

the initial installation, the resulting problems have been ad-

dressed and significantly improved with the assistance of a

committed management, concerned operating group, and in-

terested technical assistance.




Table 1.0 - Analytical Data

pH FreeHalogen Filtered Zinc Unfiltered Zinc M Alkalinity Filtered Phosphate Unfiltered Phosphate

Date East West East West East West East West East West East West East West

31-Oct-05 7.38 7.34 0.28 0.35 0.23 0.22 0.26 0.25 26 26 3.8 3.8 3.8 3.9

17-Oct-05 7.19 6.90 0.31 1.67 0.31 0.62 0.33 0.63 24 24 3.0 3.1 3.0 3.216-Sep-05 7.08 7.13 0.46 0.78 0.22 0.38 0.26 0.42 24 24 5.6 5.7 5.8 5.8

29-Aug-05 7.55 7.44 0.36 0.71 0.25 0.40 0.29 0.46 34 30 5.2 5.1 5.3 5.2

19-Aug-05 7.30 7.29 0.19 0.27 0.26 0.30 0.29 0.34 24 24 4.9 4.9 5.0 5.0

08-Aug-05 7.15 7.50 0.20 0.41 0.20 0.26 0.24 0.31 22 28 5.4 5.1 5.6 5.2

25-Jul-05 7.74 7.65 0.15 0.20 0.15 0.20 0.20 0.24 28 24 5.2 5.0 5.3 5.0

15-Jul-05 7.58 7.43 0.19 0.30 0.13 0.18 0.19 0.24 28 26 4.3 4.9 4.6 4.9

28-Jun-05 8.37 8.39 0.22 0.28 0.14 0.28 0.22 0.35 84 86 5.2 5.0 5.4 5.0

17-Jun-05 7.30 7.39 0.39 0.52 0.13 0.26 0.19 0.31 34 34 5.8 5.8 5.9 5.8

06-Jun-05 7.71 7.59 0.38 0.39 0.15 0.31 0.20 0.38 46 35 5.7 5.7 5.9 5.9

26-May-05 7.51 7.40 0.56 0.67 0.16 0.27 0.20 0.32 5.7 6.0 5.8 6.2

13-May-05 8.10 7.59 0.41 0.76 0.15 0.27 0.25 0.36 82 78 5.0 4.9 5.5 5.0

06-May-05 9.06 8.81 0.22 0.15 0.12 0.16 0.21 0.30 100 100 5.1 5.3 5.3 5.6

27-Apr-05 7.78 7.80 0.46 0.72 0.17 0.22 0.22 0.27 78 78 6.1 6.2 6.3 6.3

18-Apr-05 8.02 8.04 0.41 0.52 0.22 0.21 0.25 0.26 78 76 6.0 6.1 6.3 6.3

08-Apr-05 7.86 7.79 0.27 0.90 0.24 0.30 0.33 0.38 68 68 5.9 5.9 6.1 6.0

01-Apr-05 7.85 7.73 0.27 0.84 0.29 0.37 0.42 0.52 68 68 5.9 5.9 6.0 6.0

23-Mar-05 7.95 7.80 0.18 0.91 0.30 0.40 0.39 0.54 68 68 6.0 5.8 6.1 5.9

16-Mar-05 8.00 8.00 0.35 0.52 0.22 0.43 0.35 0.43 70 69 6.3 6.1 6.4 6.3

09-Mar-05 8.00 7.92 0.52 0.65 0.24 0.31 0.40 0.48 62 64 6.0 6.3 6.0 6.5

02-Mar-05 7.73 7.95 0.51 0.75 0.27 0.34 0.34 0.40 68 68 7.1 7.1 7.2 7.3

23-Feb-05 7.79 7.71 0.41 0.74 0.20 0.25 0.29 0.34 68 66 6.6 6.5 6.8 6.6

16-Feb-05 8.02 8.01 0.35 1.04 0.20 0.26 0.32 0.38 7.1 7.3 7.2 7.5

11-Feb-05 7.44 7.49 0.39 0.98 0.20 0.29 0.22 0.32 7.3 7.3 7.5 7.6

08-Feb-05 8.01 8.08 0.51 0.48 0.20 0.25 0.22 0.26 7.7 7.7 7.9 7.9

03-Feb-05 7.72 7.68 0.66 0.86 0.20 0.22 0.25 0.33 8.2 8.2

14-Jan-05 8.21 7.89 0.42 0.29 0.07 0.11 0.07 0.15 84 72 8.5 8.4 7.5 7.7







Cooling Technology Institute

Licensed Testing AgenciesFor nearly thirty years, the Cooling Technology Institute has

provided a truly independent, third party, thermal performance

testing service to the cooling tower industry. In 1995, the CTI

also began providing an independent, third party, drift

performance testing service aswell. Both these services are

administered through the CTI

Multi-Agency Tower Perfor-

mance Test Program and provide

comparisons of the actual operat-

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tower installation to the design

performance. By providing such

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installation, the CTI Multi-

Agency Testing Program stands

in contrast to the CTI Cooling

Tower Certification Programwhich certifies all models of a

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To be licensed as a CTI Cooling Tower Performance Test

Licensed CTI Thermal Testing Agencies

License Agency Name Contact Person Telephone

Type* Address Website / Email Fax

A,B Clean Air Engineering Kenneth Hennon 800.208.6162

7936 Conner Rd www.cleanair.com 865.938.7569

Powell, TN 37849 [email protected]

A, B Cooling Tower Technologies Pty Ltd Ronald Rayner 61 2 9789 5900

PO Box N157 [email protected] 61 2 9789 5922

Bexley North, NSW 2207

AUSTRALIA

A,B Cooling Tower Test Associates, Inc. Thomas E. Weast 913.681.0027

15325 Melrose Dr. www.cttai.com 913.681.0039

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A, B McHale & Associates, Inc Thomas Wheelock 865.588.2654

6430 Baum Drive www.mchale.org 425.557.8377

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* Type A license is for the use of mercury in glass thermometers typically used for smaller towers.

Type B license is for the use of remote data acquisition devices which can accommodate multiple measurement locations required by larger towers.

Licensed CTI Drift Testing Agencies

Agency Name Contact Person Telephone

Address Website / Email Fax

Clean Air Engineering Kenneth Hennon 800.208.6162

7936 Conner Rd www.cleanair.com 865.938.7569

Powell, TN 37849 [email protected]

McHale & Associates, Inc. Thomas Wheelock 865.588.2654

6430 Baum Drive www.mchale.org 425.557.8377

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Agency, the agency must pass a rigorous screening process and

demonstrate a high level of technical expertise. Additionally, it

must have a sufficient number of test instruments, all meeting

rigid requirements for accuracy and calibration.

Once licensed, the Test Agenciesfor both thermal and drift testing

must operate in full compliance

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Manuals which were developed

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specifically for this program. In-

cluded in these requirements are

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Cooling tower owners and manu-facturers are strongly encouraged

to utilize the services of the licensed CTI Cooling Tower

Performance Test Agencies. The currently licensed agencies are

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Albemarle 67

Aggreko Cooling Tower Services 36, 37

AHR Expo 69

Amarillo Chittom AirFlo 55

Amarillo Gear Company IBC

Amcot Cooling Tower Corporation 23

American Cooling Tower, Inc. 15, 51

AMSA, Inc. 25, 57

Bailsco Blades & Castings, Inc. 56

Bedford Reinforced Plastics 17

Beetle Plastics, LLC 21

Brentwood Industries, Inc. 9

ChemTreat, Inc. 13

Clean Air 41

Cooling Tower Resources, Inc. 33

CTI License Test Agencies 68

CTI ToolKit 70, 71

Dynamic Fabricators, LLC 7

Engelhard Corporation 35

Gaiennie Lumber Company 2

Goodway 63

Howden Cooling Fans 5

Hudson Products Corporation 29

Industrial Cooling Tower 58,IFC

KIMCO 45

LaMotte 6

McHale and Associates 31

Metrix 61

Midwest Towers, Inc. 53

Moore Fans 47

Multi-Wing America, Inc. 49

Myron L Company 4

Paharpur Cooling Towers Ltd. 39

Rexnord 3

C.E. Shepherd Company, L.P. 27

SPIG 59

Spraying Services, Inc. 11

SPX Cooling Technologies OBC

Strongwell 19

Swan Secure Products, Inc. 65

Tower Performance, Inc. 72

Vangd 18

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