WEB DEFLECTION ANALYSIS

AND

THE USE OF WEBMAPSOFTWARE

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OUTLINE

A WEB DEFLECTION SURVEY IS.. WHY RUN WEB DEFLECTIONS TOOLS AND TECHNIQUES WEBMAP DEVELOPMENT CASE HISTORIES DEMONSTRATIONS: SOFTWARE

and HARDWARE

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A WEB DEFLECTIONSURVEY IS:

MEASURING CRANKSHAFT WEBFLEXURE AS A FUNCTION OFCRANK ROTATION

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WHY CONDUCT A SURVEY

REALIGNMENT / MAJOR REPAIR ROUTINE MECHANICAL

INSPECTION

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Repairing Block Separation

Courtesy: Adhesive Services

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CRANKSHAFT BEHAVIOR

Large crankshafts are flexible Can sag 60+ mils from gravity Crankshaft assumes frame shape

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Courtesy: Clark Bros Co.

FACTORY ASSEMBLY: TCV-16

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FINAL GRIND

Courtesy: Fusion, Inc.

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CRANKSHAFT BEHAVIOR Bending takes

place primarilyin the webs!

Web acts like ahinge

Max stressesoccur at thefillets

Apparent hinge points

Location of max stress

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WEB DEFLECTION MECHANICS If the bearings in a machine are not precisely

aligned, the crankshaft webs will move fartherapart or closer together as the crankshaft isrotated.

Bearings alignedweb deflection zero

Bearings misalignedwebs closer togetherwith pin up

Bearings misalignedwebs farther apartwith pin down

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Courtesy: Philadelphia Resins

GAS PLANT COMPRESSOR

DONT

I

WISH!

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KING RANCH GAS PLANT TLA-8

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Clark Cross-section

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DISTORTION GAGE BETWEEN WEBS

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THE WEB DEFLECTION ISOVER THE LIMIT !!

TheSuperintendentis going to killme!

Easy, Now,Dont Panic.

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GET AN ACTION PLAN !

Check tools/ Rerun survey. Suspect bad bearings before

suspecting distorted frame. Check bearing clearances. Replace bearings as necessary. A bent crankshaft is rarely the

cause of excessive deflections.

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The Web Deflection Survey

Tools Techniques Recording the data (Forms to use) Units (Inches, Mils, MM, Whatever) Maximum Limits

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TOOLS FOR THE SURVEY

INSIDE MICROMETER STARRETT DISTORTION GAUGE INDIKON ELECTRONIC GAUGE LASER ALIGNMENT KIT

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INSIDE MICROMETER

USED BY DRESSER-RAND CAN REACH BETWEEN VEE RODS SLOWER AND MORE DIFFICULT

THAN USING A DISTORTIONGAUGE

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STARRETT DISTORTIONGAUGE

TRADITIONALLY RECOMMENDED SUBJECT TO SOME UNCERTAINTY FULLY ADEQUATE

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DISTORTION GAGE AND EXTENSIONS IN BOX

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STARRETT TECHNIQUES

USE FACTORY POINTS AVOID BENT EXTENSIONS REVIEW ACCURACY

PERIODICALLY USE CARE REGARDING PUNCH

MARK INDENTIONS

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INDIKON ELECTRONIC

VERY HIGH RESOLUTION SOMEWHAT COMPLICATED PROVIDES ANGULAR DATA RECOMMENDED, BUT IS NOT

NECESSARY WHEN USINGWEBMAP

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LASER ALIGNMENT KIT

THEORETICALLY EXCELLENT NOT YET DEVELOPED AS AN

APPLICATION DETECTS OFFSET AS WELL AS

ANGULAR MISALIGNMENT

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FACTORS AFFECTING DATA Condition of the Tools Positioning of the Tool Temperature of the Engine Temperature of the Instrument Condition of the Punch Marks Extensions: Bolts or

Counterweights

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EXTENSIONS

RECORD EXTENSION LENGTHS DO NOT RECORD CORRECTED

READINGS AS DATA CORRECT FOR EXTENSION LATER WEBMAP CORRECTS READINGS

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Maximum Deflection Limits Three mils is about the number

you will hear for most largeengines (10 to 20 inches of stroke)

It is best considered a function ofthe stroke length

Traditional formula 0.18 mils /inch of stroke (Courtesy: CooperEnergy Services)

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Recording the Data

Do not use inches Make written marks in Mils Use a form for recording data Employ circles for the data, not a

table Show approximate angle for data

points

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This Many Inches Deflection?This Many WHAT?

0.00025 Inches, You say? 0.0025 Or was it this many? Uh...Well. It was about a quarter

of a mil. I was looking at it!

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INCIDENTAL DATA

DATE AND TIME ENGINE SUMP TEMPERATURE MECHANICAL CONSIDERATIONS COMPLETE IDENTIFICATION

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Typical Deflection Readings

As Viewed From Oil Pump End

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FILE The DATA

Keep a good file on location or atthe nearest field office.

Send a copy to the area engineer.

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WEBMAP DEVELOPMENT

EXXONS KING RANCH GASPLANT

ALIGNMENT PROBLEMS GROUT CREEP ASSISTED BY RAY JAMES CONVERTED TO PC BY GMRC

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Courtesy: Cooper Bessemer

THE QUESTION WEBMAP ANSWERS

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MATHEMATICAL BASIS

ASSUME A HARMONIC FUNCTION DEVELOP A SIMPLE ANALOGY INCLUDE ENGINE GEOMETRY THE RESULTS APPLY DIRECTLY

TO THE SHAFT, BUTINDIRECTLY TO THE FRAME

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APPLYING THE THEORY

CHOOSE A ZERO REFERENCE FIT WEB DEFLECTION DATA TO A

SINE FUNCTION FORMULA FOR CORRECTIONS FOR

EXTENSIONS RELATES ENTIRE SURVEY FOR

VERTICAL AND HORZ. PROFILES

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WEBMAP ANALYSIS

SCREENS FIELD DATA CORRECTS FOR EXTENSIONS EXTRAPOLATES FOR 360 DEGREES GENERATES A LONGITUDINAL

PROFILE OF THE INFERREDFRAME POSTURE

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EXAMPLES OF WEBMAP

KVR CASE CONFIRMS CRUCIALDATA

HRA CASE ILLUSTRATES HEATEFFECTS

OFFSHORE GMVA DATACONFIRMS FRAME DISTORTIONMEASUREMENTS

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INGERSOLL-RAND 3400 HP KVR

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CRANKSHAFT ALIGNMENTAND WEB DEFLECTIONS

WHY RUN A WEB SURVEY DOING SURVEYS RIGHT WHAT WEB SURVEYS REVEAL THEY WILL ALWAYS BE

NECESSARY

BUT...

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BUT...THE WEB SURVEY

IS ONLY AN INDIRECTINDICATOR OF FRAME ALIGNMENT

BEST PRACTICES CALL FORDIRECT MEASUREMENTS OFFRAME SETTING POSTURE ANDPOSITION?

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NEW SPLIT STEEL CHOCKS

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