Hi,
Some of hydro test general perception either for mobile / rigged test bench that I can think of:
a.Valve, should be:
[ul]
[li]Able to regulate / fine tuning pressure : by far this is performed better by Needle valve[/li]
[li]Quick operation for filling (especially for large volume valve) / quick draining (after testing) / quick closing (after xx,xx Psig designated pressure achieved) : normally used are Ball valves[/li]
[li]Tight shut off / zero leakage: Soft seated (normally Ball) valve[/li]
[/ul]
b.Service: water with or without inhibitor
Always think it comes from unreliable (clean) source, used for multiple testing, used for testing dirty valve. The bottom line is: the water is dirty
Dirt will: trapped in the valve cavity (causing Gate valve unable to fully close after sometime), causing soft seated ball valve starts to leak, etc.
By that aspect valves should be maintainable / replaceable easily and not suggested for socket welding. Threaded or flange type is more suitable.
Socket weld is more for Helium testing if someone would minimize leakage path.
If you have other reason for using socket weld, maybe top entry ball valve is a good choice for blocking purpose. Suggest to remove the soft seated first before welding it.
Or else, if you want to have one valve that can do all (block and regulate) maybe 1 or 2 Globe valve can do the trick (Metal seated).
Regards,
MR
All valves will last for years, except the ones that were poorly manufactured; are still wrongly operated and or were wrongly selected
