Testing Methods & Standards for Brass Spring Check Valve??

In a properly designed check valve there should be little or no flow back once the valve is closed.

You must have a defective check valve there.

Dear Frank787

Thanks for your immediate assistance.

But how could we define the "little"?

I have no testing methods or standards to check if it is defective.

Could anyone advise?

Jones

There are standards available for this, for example you can always rely on API 6D where in general all the requirements and tests to be carried out are covered.

(Usually no visible leakage at minimum 1.1 rated pressure)

Dear SB,

Thanks. I will check API 6D.

By the way, I have question about 1.1 rated pressure.

It means 1.1 Mpa, right?

thanks.

Jones

Dear Jones,

There is dedicated standard available for brass-bronze gate globe & check valves,i.e.MSS-SP 80.In this u can get design,testing mathod,test pressure w.r.t.rating .

rated pressure means : e.g. if ur valve rating is 150#,then your valve will have a rated pressure of 19 bar,as per asme b 16.5.this value is selected based on max.ratio of pressure/all.stress at temp. from table.

I had a similar problem on a potable water system and on disassembling it to do a visual inspection,found that the spring had deteriorated which lessened the tension against the disc,which also was worn bad,and there was debris inside the chamber the seat was pitted,and the labor involved with the removal of this particular valve was intense,so I just replaced it.It was'nt very much, I think it was less than $100 for a 2 inch.It was a common and easily availiable valve,and I had ordered it and had it on board before I did anything.But, if your valve is very expensive to replace and is on a critical system,my method probably won't work too well. hope you solve your problem,Skip

On an earlier series of fire trucks, we spec'd. spring loaded check valves for fast filling. The original design were not well sealing, and always leaked. When we forced the manufacturer to change to better sealing valves, the problem went away except one side of one truck. The four inch pipe was long enough to reach into to check for the problem. It seems a frog had crawled into the supply hose attached to the hydrant. When the driver filled his truck, the frog got half way through the check valve. When I reached into the pipe I found the other half.

How was your day?

I think it normally happens:i should work a little with some abrasive paste,and clean, it will finish any leakage at all.

1.1 rated pressure means if the valve is rated for schedule and say the pressure rating is 20kg/cm2 (3000PSI) then the testing should be done at 22kg/cm2

Pl note this is not the pressure at which the system is working but what the valve is designed for.

Idon't try to remember the exact values and rarely i look for in tables but i remember the air compressors gauges: 14 kg/cm2 is almost 200psi so 3000psi is not 20kg/cm2.The rest of your comment is very useful to me:i thought it was like in hoses test pressure ¿four times? work pressure.-

It sounds as though the <...testing methods...for Brass Spring Check Valves....> are already being deployed. They are, after all, relatively simple things.

One assumes that the valve is installed such that gravity will close it when there is no flow, is that right?

<...water volumn is less than 1 kg...>

What does that mean?