2 replies to this topic

[MusaP1]

Hi everyone,

In the process i'm studying
there's a control valve in service water system in living quarters platform.
The treating fluid is seawater.

the valve set pressure is 125 psig,it has to dump excess water when the pressure in pipeline come to the set pressure (when little water usage).

anyway,there's an orifice plate at the downstream of the PCV before draining overboard.
for my understanding, the orifice plate is used for reduce the pressure drop across the PCV and help prevent the water hammer.
Now the PCV generates noise when little water usage.and dued to problem of obsolete,now im going to buy a new PCV

what should i do to solve the noise problem.?
is it because of undersize of PCV outlet port?

piping up/down stream of valve size 3" and reduce to 1 1/2" at control valve.
orifice size 7/8".

currently valve : fisher control Type 616-EZ size A,control differential:increasing,pressure:Open,spring range 26-130,Max Diff Press=200
Body size 1 1/2" Port size 1 1/2"
Rating:Class 300
Flow char:Q-open
Travel 7/16"
Trim:K-Monel

(offshore suggested max diff pressure across PCV should be more than 180 psig)


If you need more information,please feel free to tell.
i'm appreciated all your answers.

[joesteam]

The Fisher rep should be able to perform a noise calculation, it is part of the tools they have (I am one of these reps).
They will need to know your maximum flow, and also the Cv of the orifice plate. This plate - as well as preventing cavitation - will take a pressure drop and reduce noise through the valve.

[Zauberberg]

Look at this article: http://www.kcicms.co...f?resourceId=81

It provides you with an algorithm for aerodynamic noise calculation as per IEC 60534-8-3.
The second document http://www.iceweb.co...trol Manual.pdf discusses, amongst other topics, different ways of reducing the noise generated across the control valve.