Dead Weight Tester used in Hydrotest
Dead Weight Tester used in Hydrotest
(OP)
We need to do a pretest on a pipe at 350psi for 4hrs. Will report the air content at 0.2% of volume by using a dead weight tester to pressurize the system to target pressure.
1) So in the UUT port of my DWT i will attach a pressure transducer (for the pipe pressure reading) and connected in series with the pipe system. Is that ok?
2) However, I only have a DWT with oil medium.
How can I convert it to water?
3) Im obviously no piping engineer but i want to learn more on pipe testing (hydro and air), can you suggest any good reference for starter like myself?
Highly appreciate your generous thoughts.
1) So in the UUT port of my DWT i will attach a pressure transducer (for the pipe pressure reading) and connected in series with the pipe system. Is that ok?
2) However, I only have a DWT with oil medium.
How can I convert it to water?
3) Im obviously no piping engineer but i want to learn more on pipe testing (hydro and air), can you suggest any good reference for starter like myself?
Highly appreciate your generous thoughts.





RE: Dead Weight Tester used in Hydrotest
RE: Dead Weight Tester used in Hydrotest
RE: Dead Weight Tester used in Hydrotest
I only got the idea from California State Lands Commission
A Procedure for the Hydrostatic Pressure Testing of Marine Facility Piping (as per attached, page 11).
So initially my pipe is already filled with water using an external pump and I will just raise the pressure using a DWT.
It seems I cannot use a caibrated pressure gauge as the requirement for the pressure test is quite tight, 0.2% accuracy.
A manufacturer suggested that I can have a 2~3 m stainless pipe and fill it up oil, hence when I do the test, the water will not go into my DWT. But Im not sure if there's any effect in the accuracy of my measurement.
RE: Dead Weight Tester used in Hydrotest
If you operate with an oil column, you could correct the reading based on the known height of the column, adding or subtracting the piezo head difference caused by the difference in specific gravity of the oil relative to water. If you do this calculation, you will find that the difference is pretty trivial (about 0.1 psi or so for typical oil s.g. of 0.8) for a few feet of oil column.
RE: Dead Weight Tester used in Hydrotest
Instead of the pressure difference due to specific gravity, will it be a greater concern for me about some possible bubbles or trapped air as I need to compute for the air content.
RE: Dead Weight Tester used in Hydrotest
RE: Dead Weight Tester used in Hydrotest
Truly appreciate your inputs and patience with me.