Valve Differential Pressure On Trunnion Mounted Ball Valve

[JustABallValve]

A customer is reporting issues with operations of a BV, they have a differential pressure of about 120 PSI between the 2 seats. 1220&1100 PSI.

Should the published torques be increased when both seats are pressurized as appose to only 1 seat?

 

[LittleInch]

So this is differential pressure, i.e. 1220 one side and 1100 the other?

What is the valve pressure in the body?

If very low then possibly would need to increase, but normally you would assume that the pressure is at or close to one side or the other, but I guess the valve could be closed with low pressure in the valve which then increased over time?

Need a bit more information here on how the valve was operated.

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[JustABallValve]

So this is differential pressure, i.e. 1220 one side and 1100 the other? Correct

The valve is DBB so i would assume that any trapped pressure in the cavity would be relived to the LP side. (1100)

 

[LittleInch]

The key is though what was the pressure in the valve cavity when the vane was closed ...

Is there any leak or drain from the valve body?

If not then no, there should not be any increase as torques is based on full DP.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.