Probelm with MOV passing
Probelm with MOV passing
(OP)
Dear,
I have a problem with MOV motor operated valve paaing through. when I looked at the MOV data sheet, it was not speified that the valve as Tight Seal Closed but it is referred the seat leakage rate to API 598. So, i realized that the passing from the seat. Can any body help me to find a way to stop the passing?
Thanks
I have a problem with MOV motor operated valve paaing through. when I looked at the MOV data sheet, it was not speified that the valve as Tight Seal Closed but it is referred the seat leakage rate to API 598. So, i realized that the passing from the seat. Can any body help me to find a way to stop the passing?
Thanks





RE: Probelm with MOV passing
Pump the lubricators with grease.
Remove and send the valve to a shop.
RE: Probelm with MOV passing
I fthis is correct I will support JLSeagull and add that a first class actuator will have both torque and limit switches for open and closed included.
In this case it is important that the closing (and opening) is stopped by the limit switches at a point where the valve is thight enough.
The torque switch for closing should be set/adjusted higher than the necessary closing torque, but not used to stop the valve in closed position, or stop the valve before properly closed. (The limit switch will give closed position, and should be accordingly adjusted, as mentioned above).
If valve is not thight enough after adjustment: seat or seat-sealing is damaged or you have a non-satisfactorily valve in general.
RE: Probelm with MOV passing
RE: Probelm with MOV passing
RE: Probelm with MOV passing
As suggested by ione, check your paperwork & verify the original seat leakage class requested, and remember that there is no such thing as a "zero-leakage" valve, even though you may see the term mentioned, it basically tells you how much a "zero-leakage" valve can pass; Eg. class V allowable leakage rates (critical service) 5 x 10-4 ml per minute of water per inch of orifice diameter per psi differential (5 x 10-12 m3 per second of water per mm of orifice diameter per bar differential).
Ciao,
RE: Probelm with MOV passing
RE: Probelm with MOV passing
Ciao,
RE: Probelm with MOV passing
Could you please give all details of fluid, pressure, valve, observed leakage and desired thightness.
You have either damage, unsuitable valve, or comability problems.
RE: Probelm with MOV passing
How do you notice and/or measure that?
The six Leakage Classes for Control Valves may be a good reference just to speak a common language... but please remember that the relevant standards"cannot be used as a basis for predicting leakage at conditions other than those specified" (see IEC 60534-4, NOTE to para. 4.2 and/or FCI-70-2, para. 2.2).
Regards, 'NGL
RE: Probelm with MOV passing
1. What type of valve do you have?
2. Define the leaking gas (type, pressure, temperature)
3. Measure or estimate the amount of leakage. A few bubbles per minute or is it blowing through like the valve is partially open?
From this, we can direct the dialogue towards a conclusion for you.
RE: Probelm with MOV passing
RE: Probelm with MOV passing
GTStartup - I believe you!