We have purchased several manifolds from an instrument vendor and during our full range pressure testing we have found a portion of them begin to leak out the handle of the process isolation valve. When the leak occurs it is a definite cracking sound at higher pressures (3500-4500psig) and the first drop of water is milky white, then they run clear from the water in the pressure tester. Any ideas on what is failing? It seems to me it is a supplier quality issue and the vendor should be testing their products across the full rated range. (These manifolds are rated up to 5000psig)

 

>It seems to me it is a supplier quality issue and the vendor should
> be testing their products across the full rated range. (These
> manifolds are rated up to >5000psig)

Agreed.

Not too long ago I encountered a newly installed gauge pressure transmitter ranged -0.8 atm to +1.0 atm that was indicating a continuous leak through a seal.

When the transmitter was isolated with a -0.5atm vacuum between the valve and the transmitter, the indicated gauge pressure would slowly increase towards atmosphere as the vacuum slowly dissipated.

So instrument valves can leak at low pressures, too.

 

Luke,

ASAP make vendor returns with attached test reports. And look for
suppliers with better product quality.

PETER MACALUA
PORT ARTHUR TEXAS