Control Valve Seat Leakage

1% = 0.01; thus 0.01% = 0.0001, which is the multiplier you need. Then 100 x 0.0001 = 0.01 units of leakage (presumably gpm).

so for my example 100 x 0.0001= 0.01 gpm or 37.85 ml/min so when converted to Bubbles/min it should be 252.33?

Oh and can you suggest the test equipment to measure the leakage rate? thanks

Hi,

Well spotted by Tornado (0.1%) not the easy to make error of one tenth.

The valve CV of 100 is a "flow factor" and needs to be checked as to the "flow" I know that for compressed air a CV of 1 is 1000 litres per minute. It should be easy to "Google" the CV.

Best regards,

John

Yes, put a container to catch the leaked fluid, run for a measured time, then pour into a measuring cylinder or similar to find the volume.

Cheers.....Codey

If your calculations are correct in being 253 Bubbles per minute, it is almost impossible to count at this rate. Go back in calculating and use a flowmeter to capture the amount leaking out in the class IV identified. I'm guessing this is a metal seated valve.

Your right about doing the leak test with valve fully closed.

Most class IV valves are metal seated valves, the measured leak should be within spec. Should the leak be higher, considder overhauling the valve.

Keep in mind that regulator class IV valves are no "shut-off valves", most of the regulator valves (should) operate in the range of about 80% of full travel. Then the laek-rate doesn't affect the regulating process at all.