Equivalent Length Values

[chicopee]

Has anyone seen or remember Equivalent Length published values for Internal Valve with integrated Excess Flow Valves used on LPG tanks. Size of these valves would range from 1-1/2" to 5". I already have values for fittings, Ball/Globe and Check valves.

 

[vzeos]

If you know the EFVs Cv you should be able to calculate the equivalent length. The attached links seem to have pretty good equivalent length calculators.

http://www.uengineer.com/equivleng1.htm

http://kirkmansoftware.com/

 

[chicopee]

Vzeos-The EFV is like a restriction inside the internal valve to the tank and I found no data such as the coefficient factor K that would allow me to determine head loss. I may have to guesstimate. Installation of EFV's on propane tanks is fairly new material in the NFPA 58. Perhaps I should check out Ammonia tank safety devices.

 

[vzeos]

chicopee- I'm familiar with EFVs. We've used them in natural gas service lines for many years... Most manufacturers of flow components can provide you with the component capacity in terms of a Cv value from wich you can calculate the K value from K=891*d^4/(Cv^2) (see Crane page 3.4).

 

[chicopee]

vzeos- Is your formula for the K value derived for a specific gravity of one? I don't have crane but I'll check out my mechanical and chemical handbooks.

 

[vzeos]

chicopee- I would recommend getting a copy of Crane Technical Paper No. 10, if you can... K is independent of fluid and specific gravity... In the formula, Cv expresses flow rate in gallons per minute of 60 F water with 1.0 psi pressure drop across the valve.

 

[chicopee]

vzeos- You gave me the tip that I just needed.