Using valve in place of orifice
Using valve in place of orifice
(OP)
I have been tasked with specifying a valve to replace an orifice that the client has been unable to properly size after several calculations and attempts. The orifice is a 7/32" plug-resistant orifice in a 1" line that is a bypass around a 3" extraction steam line drain AOV to a condenser at vacuum. The idea is that an operator can set the bypass valve such that the 3" AOV only cycles less than once per shift and should the AOV start to cycle more frequently, the bypass valve can be adjusted to eliminate the cycling. The existing orifice sizing calc says the orifice passes approx 1,500 lb/hr of condensate with the design upstream pressure of 273 psia and design outlet of 1.7 psia, temp 409F.
I have asked Fisher to specify a globe valve for this and Valve Technologies to specify a metal-seated ball valve for a normal flow of 2,000 lb/hr and max of 5,000 lb/hr and they have done that but having little experience with valves in this type of service, I'm not sure what the best choice would be in terms of longevity and ability to control flow and would appreciate any input. I already suggested upsizing the orifice again but that didn't go over well.
Fisher:
1" EZ Globe made w/ WC9 steel body, ANSI 600# SW ends, flow down, Equal pct characteristic, unbalanced, 316 plug
Valve Technologies:
Valvtechnologies # C5L12SA2SA0A Metal Seated Ball Valve, ANSI 300# Class, A182-F22 material, Mark I Control Valve with characterized upstream seat guide, 0.625” Ball Bore, Chrome Carbide Hardcoated A182-F6a Ball and Integral A182-F22 Seat, Zero Leakage
Thanks!
Matt
I have asked Fisher to specify a globe valve for this and Valve Technologies to specify a metal-seated ball valve for a normal flow of 2,000 lb/hr and max of 5,000 lb/hr and they have done that but having little experience with valves in this type of service, I'm not sure what the best choice would be in terms of longevity and ability to control flow and would appreciate any input. I already suggested upsizing the orifice again but that didn't go over well.
Fisher:
1" EZ Globe made w/ WC9 steel body, ANSI 600# SW ends, flow down, Equal pct characteristic, unbalanced, 316 plug
Valve Technologies:
Valvtechnologies # C5L12SA2SA0A Metal Seated Ball Valve, ANSI 300# Class, A182-F22 material, Mark I Control Valve with characterized upstream seat guide, 0.625” Ball Bore, Chrome Carbide Hardcoated A182-F6a Ball and Integral A182-F22 Seat, Zero Leakage
Thanks!
Matt





RE: Using valve in place of orifice
Geoffrey D Stone FIMechE C.Eng;FIEAust CP Eng
www.waterhammer.bigblog.com.au
RE: Using valve in place of orifice
What's the Cv of each valve at 20% and 80% open? If you want help, give us some data that is helpful.
What noise level is expected of each valve? I agree with stanier, you should fax a spec off to CCI, quick! It'll be extremely expensive (more mark-up for the contractor!), but it'll be quiet and last forever!
I expect more than this from a fellow NCSU graduate! Anticipate!
Good luck,
Latexman
RE: Using valve in place of orifice
RE: Using valve in place of orifice
Good luck,
Latexman
RE: Using valve in place of orifice
ValvTech is still working on a CV curve and CCI priced themselves out of consideration
RE: Using valve in place of orifice
RE: Using valve in place of orifice
RE: Using valve in place of orifice
% CV
30 0
50 .23
70 1.0
90 1.5
100 1.56
I asked them to defend their choice of the Mark I over the Mark III which has pressure reducing plates upstream and they said the Mark I is more than capable of handling the pressure drop. Both valves would operate between 50-70% open
RE: Using valve in place of orifice
And once again, what are the prices? Comparable? % difference?
What is the warrantee period against wire-draw for these two valves? Just for kicks, what was the warrantee on the CCI valve?
Good luck,
Latexman
RE: Using valve in place of orifice
"Most of the pressure drop occurs in the Mark I upstream of the critical seating surface through the characterized orifice in the upstream seat guide. Your maximum pressure drop under normal conditions is only 278 PSIG. The seating surfaces of the Valvtechnologies Ball Valve are Chrome Carbide that has a Rockwell C hardness of 66-69.
Typical Valves use Stellite that is approximately 46."
The area downstream of the ball is "RAM 31 hardened" F22 and the upstream is "H.F." (hard faced?) F22.
I don't have any warantee info for any of the valves just promisses from the sales guys that they will last