Pressure drop problem

[bzandy]

HI there,
now i am facing a problem about the pressure drop in ball valve. our company produce a kind of ceramic ball valve against high corrsion and high temp, which was inquried by a mid-east petrochemcial company. the engineer ask for the pressure drop of our reduced ball valve. the ball valve we ganna provide is a reduced version: inlet is 4", but the orifice of ball is only 3", so there must be some pressure drop exist. however, our company never do this kind of experiment to test the flow rate, so is there anybody has any method to give the approximate pressusre drop calculation method. thanks in advance!

 

[Unotec]

You are the manufacturer and you don't have this data? I'd suggest getting it, as the pressure drop will be dictated by your valve's geometry in the internals. Personally, I'd have a hard time buying a valve from a manufacturer that could not supply this info

<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying ” Damn that was fun!” - Unknown>>

 

[belowzero]

It makes you wonder what kind of manufacturers are actually selling valves, when they don't have this basic information. If these valves are being purchased and they most surely are as this one obviously has a market they are catering to, then the standard and quality must also be an unknown factor, an accident waiting to happen maybe.
Engineers had responsibility to fit goods which not only complied with standards and specifications but came from companies who have both the experience and background to know what they are doing. Has this now all gone?
I too would question the purchase of valves from this manufacturer.
B

 

[Unotec]

bzandy, I guess there's no chance to tell us which manufacturer you are, is it?

<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying ” Damn that was fun!” - Unknown>>

 

[rconner]

Maybe would be OK for some applications, at least until someone tried to run a firm full-size pig through the lines (then maybe there would be some real high pressure drop!) See thread

http://eng-tips.com/viewthread.cfm?qid=230721&page=1

below that some folks are apparently now offering more full-port valves, that might help at least a little in pressure drop, as well as allowing pig passage if that is an issue.