Test to find pressure drop through valve?

[daftdave11]

Hi all

I am trying to design a test that can be carried out on a valve to calculate the pressure drop and flow coefficient through said valve. i need to have a 6 bar inlet pressure into the valve and the ID of valve will be 50mm. the fluid i am proposing to use is water. My design is to have a 100L tank and a pump attached to this to get the water up to the necessary pressure at inlet of valve. is this feasible? also what measuring devices would i need to measure the pressure at outlet? my knowledge on the topic is fairly limited. i look forward to a reply. Thanks in advance

David

 

[gerhardl]

I take it you are primarily looking for suitable equipment, secondly if your suggested test will give a result.

If you look for the test, this is a test this should be directly comparable to tests carried out to decide the Cv (or European Kv) for a valve.

Suggestion: familiarize yourselv with the formulas for Kv and Cv and tests (search for instance within this site or open on net).

When you have selected further details on your method, you will perhaps still be left with detailed questions for measurement instruments and placing of instruments, which perhaps can be asked on more specialized forums.

 

[cvg]

if you want accurate results, than focus on accurate measurement of pressure and flow. pressure gauges and flow meters have limits to the accuracy and may not be adequate for your test.

measure pressure with a manometer
measure flow volumetrically
measure flow time with a good digital timer

100 liter tank seems a bit small. You may want to have flow velocities of 10 - 20 feet/sec. this would require 200 gallons per minute flow. your tank should hold enough water for maybe 1 minute of run time.

 

[reverman]

Get a copy of "Crane Technical paper 410" it has some nice pictures and descriptions of the test rig they used. Plus the Paper is a great resource for valve flow calculations in general.