testing bench for RTJ end valves

[mbelly84]

Sorry for the weird question here.

Usually, when customers ask us to test RTJ valve with oval ring gaskets (to test RTJ groove integrity) we test it out of bench with blind RTJ flanges (full end thrust test).

Would it be possible to do the same thing on a vertical hydraulic testing bench (with plugs modified to accept oval rings)?
Would the reaction force on the bench be enough to simulate bolt preload on an RTJ flange?

 

[Danlap]

Hello,

The answer is Yes (possible).
Conservatively (without considering internal pressure which can vary from 600 Psig to 10,000 Psig or more let say), the Sealing/seating stress (σ) for metal gasket (RTJ) is 125 MPa(RTJ soft iron) up to 180 MPa (RTJ Stainless Steel).
Therefore: your RTJ diameter are outside dia. (OD) and inside dia. (ID).

Minimum force to be exerted by the test bench will be simplified as:
F =σ x A = σ x 1/4 x Π x (OD^2 - ID^2)

No, its not weird question.
Good luck,
Regards,


All valves will last for years, except the ones that were poorly manufactured; are still wrongly operated and or were wrongly selected

 

[Piper1962]

Usual practice is to use test flanges/plugs that have O-ring grooves. The O-ring seats on the raised face of the valve flange inside of the RTJ groove. The O-rings of course need much less sealing force.
Testing in a clamp is frowned upon for valves with split bolted bodies (end entry ball valves for instance) because the flange body joints are compressed by the test clamp.