Greetings!We need urgent help :) 6 pcs of 38" triple-offset butterfly valves are passing (more than 50% of number installed).Automatic Control Valves The valves worked fine for about 12 months. Increasing the torque from 75% to 100% didn't help.Service: isolation valves for mercury removal filters (dry natural gas)Class 600#Pop = 66 bargDP = 76 bargTop = 25 CDT = 82 CMaterials:body = A351 CF8Mseat = 316SS / GraphitePlant is 1 year old, there is a possibility of large quantity of dust / scale in the piping. Butterfly ValvesIn theory, these valves should be somewhat OK with solids in process fluid.I haven't had a chance to talk to the OEM, will do that tomorrow.Any comments on cause, rectification would be much appreciated. If you need more info please advise.can you please provide the state of disc? There maybe a couple of reasons which may cause such conditions. you may exclude any doubts one by one. Anyway, you'd better check two points following:1. Can the lever be turned? what's the angle of availability?2. Bellows Seal ValvesCheck the disc position, open or close?What is the actual flow and pressure?When 'something' is going wrong on several valves after a certain periode of operating time, and nothing 'unregular' has happened (no pressure peaks, no un-normal operating conditions, no service (opening of pipeline, foreign objects introduced) etc., no wear or mechanical slip on actuators, no wear or slip on adjustment and mechanical transmissions on outside contraptions and no unnormal temperature variations, this will, as you suggest, be inside problems.Check Valves Can you rule out condensation on inside pipeline caused by standstill and sinking temperature, or other inside moisture problems causing particles to clump or fasten to seats?Can you rule out chemical reactions and chemical wear? The inner problem(s) is most likely caused the same thing for all valves.Guesstimate is most likely wear on seats again caused by abration, and/or increased by cavitation caused by valves not beeing able to close 100% because of inital abrational wear or dust particles on seats (tiny opening increasing velocity of gas).Plug Valves If this is the case you have to look at the seat construction, materials and exposure of seat sealings and sealing rings to evaluate improvements.An idea could be to evaluate softer seat sealings.

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