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Anonymous Poster

Leakage Rate Formula

01/15/2008 5:11 AM

I would be grateful for any and all help,what is the leakage rate formula for globe type control valve ?

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Guru
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#1

Re: Leakage rate Formula

01/15/2008 5:33 AM

<....leakage rate formula....>

Eh? There's no such thing.

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Power-User
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#2

Re: Leakage rate Formula

01/15/2008 8:19 AM

I have dealt more with the mobile hydraulics industry, and I think the leakage rate should depend on the design of the valve you purchase.

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Associate

Join Date: Feb 2007
Location: Concord CA, (near San Francisco)
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#3

Re: Leakage Rate Formula

01/15/2008 3:34 PM

Dear Guest:

Contact the Fluid Controls Institute and ask for a copy of ANSI B16.104 (current version). There is a table in that which defines Leakage rates for Classes II thru VI. I have a copy of the table, but no way to scan it in for you. If you have a fax machine available, let me know the number and I'll send it to you.

Hank

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Participant

Join Date: Nov 2007
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#4
In reply to #3

Re: Leakage Rate Formula

01/16/2008 12:10 AM

Thank u v much dear,

I have this copy of leakage classification, but actually I want the exact formula thro which we can calculate the leakage rate of any control valve and the other problem is that there is no mention the leakage class on the tag plate of control valve in the field or in the data sheet,so what are the parameters or the factors need to calculate the leakage formula and most importantly what is the leakage rate formula.

Thank u v much for attention.

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Associate

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Location: Concord CA, (near San Francisco)
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#5
In reply to #4

Re: Leakage Rate Formula

01/16/2008 11:17 AM

Reyan:

Well now, at least we know your name. Glad to meet you, Reyan.

Back to the subject. I must assume you have no way of obtaining ANSI B16.104. The leakage rate of a valve is a function of design and manufacturing tolerances. There is no way to "calculate" what it will be. It's a parameter that is usually specified by the system control engineers. The only way to know if the valve meets the specified leakage rate is to test it. That's why you need ANSI B16.104...it describes the test methods necessary to determine the leakage rate for a particular valve. It's time to start Googling and looking up the information. Another source is the Valve Manufacturers Association. They would be glad to help you with this.

Good Luck. I hope I have helped you.

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Power-User

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#6

Re: Leakage Rate Formula

01/28/2008 9:02 PM
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Anonymous Poster
#7

Re: Leakage Rate Formula

07/29/2010 1:21 PM

Did you ever obtain this formula?

I'm trying to create a leakage rate chart for a local CV repair shop & need this formula as well for 50 psig air test pressure.

From what I can see Q(scfh)=1360CvP1([(P1-P2)/P1]/(GTZ))^.5,; if P1-P2 = P1, then

Q=1360CvP1/T^.5, G=1, Z=1.0, air. T=oR; P1=psia(psig+14.7)

So for Cl. II, Ql = .005 x Q

Cl. IV, Ql=.1 x Q

Can you advise how this compares to yr research?

Thanks,

Mike Cognevich

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Anonymous Poster
#8

Re: Leakage Rate Formula

07/29/2010 1:37 PM

Did you ever get this formula?

I'm trying to create a Control valve leakage chart for air at 50 psig for a local valve repair shop, so I need the same formula.

From what I can see, Q(SCFH)=1360CvP1[((P1-P2)/P1)/(GTZ)]^.5, If (P1-P2)=P1, & G=Z=1.0, Q=1360CvP1/T^.5

So for Class II, Ql=.005 x Q, Ql=leak rate(SCFH)

Class IV, Ql=.0001 x Q

Thanks & Regards,

Mike

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