I N D U S T R I A L P R O D U C T S A N D S E R V I C E S

Re-torquing vs. spring assembly height to re-apply gland load

ReRe--torquingtorquing vs. spring vs. spring assembly height to reassembly height to re--apply apply gland load gland load Ron FrisardAW Chesterton

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Valve leakingValve leakingValve leaking

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If a valve is If a valve is leaking do you leaking do you first refirst re--torque?torque?

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First attempt: Re-torque to same valuesFirst attempt: ReFirst attempt: Re--torque to same valuestorque to same values

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Maybe you are Maybe you are concerned concerned about a valve about a valve and ask to and ask to verify what the verify what the torque is now??torque is now??

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Re-torque = shooting in the darkReRe--torque = shooting in the darktorque = shooting in the dark

Anti Seize, Thread Pastes are made of oil, thickeners and lubricating solids. K nut factors are based on the “WET” or oily paste at installation only.

One time use!

Once exposed to heat cycles, oil is flashed off. “Dry” Anti-Seize properties K nut factor maybe up to 200-300% higher with wide variance

Not CANNOT get the same gland load when re-applying original torque after any heat on the valve

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“Dry” anti-Seize testing““DryDry”” antianti--Seize testingSeize testing

Using Skidmore device Using Skidmore device torque bolt to 100 fttorque bolt to 100 ft--lbs, lbs, record LOAD and calculate record LOAD and calculate K nut factor or coefficient of K nut factor or coefficient of friction of friction of ““wetwet”” thread paste.thread paste.

Remove bolts, reRemove bolts, re--lube and lube and place in oven at 500C for 6 place in oven at 500C for 6 hours to hours to ““flashflash”” off oiloff oil

Put bolt back in Skidmore Put bolt back in Skidmore and apply 100ftand apply 100ft--lbs, record lbs, record Load and calculate K nut Load and calculate K nut factor of factor of ““DRYDRY”” thread paste.thread paste.

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“Dry” anti-Seize testing““DryDry”” antianti--Seize testingSeize testing

Anti-Seize Torque Cf wet Cf dryLoctite Nickel 100 0.154 0.71 Bostick Ni Nuclear 100 0.151 SeizedLoctite N-7000 100 0.135 0.32 3 cycles, 4th seizedChesterton 772 100 0.164 0.26 2 cycles, 3rd seizedLoctite Marine 100 0.12 SeizedLoctite Heavy Duty 100 0.13 SeizedMolykote P37 100 0.121 0.349

Data average of 6 re-torquing cyclesSeized values attained 100 ft-lbs with NO Load transfer to stud. Threads galled during re-torquingN-7000, corase texture when dry, surface galling got worse with cyclesdry coating on threads being scraped off under load.Chesterton 772, ultrafine particles, smooth film when dry, surface galling with repeat cycles. Coating present yet not sufficient film strength to resist load

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What is your What is your antianti--seize seize ““drydry””coefficient of coefficient of friction and how friction and how accurate is it??accurate is it??Start askingStart asking……..

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“Prototype” Chesterton Anti-seizefocused on re-torque““PrototypePrototype”” Chesterton AntiChesterton Anti--seizeseizefocused on refocused on re--torquetorque

Anti-Seize Torque Cf wet Cf dry

772 Modified( new) 100 0.154 0.28-0.31

passed 6 repassed 6 re--torques dry, no torques dry, no seizure, no galling. Threads seizure, no galling. Threads

burnished smooth and lubricant burnished smooth and lubricant was intact.was intact.

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Valve testing dataValve testing dataValve testing data

Re-torque = 9 ftlbs- Consolidation: 9 ftlbs = 1.17” of

compressed spring height- After Cycles: 9 ftlbs = 1.188” of

compressed spring height- Dried Anti Seize- Bolt condition

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RecapRecapRecap

Re-torque not useful to gauge gland loadGetting “as found” torque not useful in telling gland loadIf thread galling occurs, re-torque is impossible.

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How accurate is Anti-seize “wet”How accurate is AntiHow accurate is Anti--seize seize ““wetwet””

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Live loading as a “load gauge”Live loading as a Live loading as a ““load gaugeload gauge””

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Chesterton Valve SpringsChesterton Valve SpringsChesterton Valve Springs

Creates stored energy with Belleville springs to postpone gland load lossSprings sets designed for specific valve data- System pressure- Dimensions (packing and bolt size)

Chesterton live loading designed over 30 yearsWhat to live load- Thermal Cycling- Vibration- Critical Dynamic Applications- Anywhere you want to measure gland load!!!

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Outer Guide Technology Outer Guide Technology Outer Guide Technology

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Outer GuidesOuter GuidesOuter Guides

Easier to re-energize then inner guide assembly Do not need scale to measure height; can use flat washer / outer guide as visualSprings stay together “in-line” / easier installation then inner guide

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Questions….QuestionsQuestions……..

Feel free to contact me at:ron.frisard@chesterton.com978-469-3993