P vs V of water
P vs V of water
(OP)
My company makes liquid level gauges (my area being boiler trim). I am working on calcs for a gauge with a valve at each end. The gauge is pressurized to hydrostatic test pressure (at 70°F) and the valves are closed. Over the course of an hour the gauge loses about 150 psig of pressure (starting pressure = 4500 psig). After performing a hydrogen leak test, it is assured that the gauge is not leaking. My thought is that the gauge glass is lifting a bit, therefore reducing the pressure. I need to quantify how much the glass would be lifting for a given pressure drop, however, I can not find any equation that would correlate pressure and volume with a liquid, specifically water. Any thoughts? Any other thoughts as to the drop in pressure?
Thanks in advance for any help!
Thanks in advance for any help!





RE: P vs V of water
RE: P vs V of water
RE: P vs V of water
Is there any temperature change? (it sure wouldn't take much)
= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.
http://www.trenttube.com/Trent/tech_form.htm
RE: P vs V of water
I have worked through the calculations using the bulk modulus equation, it seems to be giving me data that is in the realm of believable.
RE: P vs V of water
RE: P vs V of water
If it is not a leak, than my guess is that it has to do with a slight change in the temperature of the hydrotest water over the course of the test. A quick calculation shows that a temperature change from 70°F to 67°F would be enough. Even if you were monitoring temperature, this small a change might not be enough to be noticeable.
Tim