I have seen this before in 1500# TMBV, at the end of the day you as a customer will have to accept the BOM or ask for what you want.
I believe its just a cost savings practice by the manufacturer.
I am interested to hear anybody experience with cryogenic testing of TMBV at -325F, per BS6364.
The main issue i see if the valves holding the allowable leakage thru the multiple cycles at incremental pressure the test ask for.
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)
To answer your question we need more information.
1. What type of valve is this? Soft seated?
2. Is the requirement API 598 or 6D?
For API 598 A hydro seat test is not required unless specified by the customer. Also in API 6D a low pressure seat test is not required unless specified by the...
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?
