relief valves 2

[duika]

Hello,

For sizing a relief valve (surge anticipator) in a water supply pipeline i am using the next formulae:

Q = 2 x g x H / a x v

where

Q = flow to discharge
g = gravity
H = normal head
a = celerity
v = velocity of the flow

Depending the value of Q and knowing the Cv of the valve, i can calculate the diameter of the valve.The actual formulae assumes no head loss in the pipeline neither water column separation.

Is it OK?? Can i use others formulaes??

Thanks

 

[quark]

I highly suspect the equation and its origin. Q = axv and what is it doing in the denominator? Further, 2gh is the potential that causes flow, particularly for gravity flow from tanks.

Search for crossby safety valve handbook from tyco valves.

Regards,

 

[Montemayor]

Applying engineering solutions to problems is not like downloading a recipe from the Food Network. A real, professional engineer doesn't merely take a formula or equation from whereever and resolves a problem.

If you don't know the origin, the derivation, the source, or the intent and reasoning behind an equation, I wouldn't even think of applying it to a problem! Engineering is logical science and ingenuity applied to resolving problems. If you don't know how or where to obtain mathematical relationships, you are not prepared to resolve the problem at hand. You've got some research to do and background to investigate on your problem. In doing so, you'll find the appropriate mathematical relationships (if they exist) and know how to apply them.

 

[MortenA]

You should take a look at this source:

http://www.tycovalves-na.com/ld/CROMC-0296-US.pdf

Its the crossby enginering hand book. Its for API relief avlves - but it will also be true for other types.

This is the exatc same info (and some more) that can be found in API 520.

Best regards

Morten