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Dear All
Which valve comes first, Globe valve or Ball Valve In Control Valve Bypass line, Normally i used to locate Globe valve first,
But i forgot the reasion why i used, Please Advise me.
Globe in, gate out is what I was taught.
Globe in, gate out is what I was taught.
I do not remember ever seeing a control valve bypass with two valves.
In my experience 99% of all CV bypasses had one Globe valve to throttle the flow when the CV was out for maintenance or repair.
The 1% of the time was when we had a bypass that was larger than the available globe size so we used a Gate valve.
Why are you putting two valves in the CV bypass?
Does the P&ID show two valves in the CV bypass?
I do not remember ever seeing a control valve bypass with two valves.
In my experience 99% of all CV bypasses had one Globe valve to throttle the flow when the CV was out for maintenance or repair.
The 1% of the time was when we had a bypass that was larger than the available globe size so we used a Gate valve.
Why are you putting two valves in the CV bypass?
Does the P&ID show two valves in the CV bypass?
Thanks Crashtested and Jop,
Jop,
yes the P&ID shows two (globe and ball ) valves, i used many times in the Piping, I noted the in my note book that globe vale will comes first, but i forgot the reasion,
Thanks Crashtested and Jop,
Jop,
yes the P&ID shows two (globe and ball ) valves, i used many times in the Piping, I noted the in my note book that globe vale will comes first, but i forgot the reasion,
ashokaa,
You say that the P&ID shows two valves in the CV bypass.
Ok, which valve is shown first (in flow direction)?
Now since the Process Engineer is responsible for developing the P&ID, please go ask him (or her) the following:
Why two valves?
Why "that" one first?
Because I for one would like to know the answer to both of these questions..
ashokaa,
You say that the P&ID shows two valves in the CV bypass.
Ok, which valve is shown first (in flow direction)?
Now since the Process Engineer is responsible for developing the P&ID, please go ask him (or her) the following:
Why two valves?
Why "that" one first?
Because I for one would like to know the answer to both of these questions..
Ok jop,
i will check and come back to you,
Ok jop,
i will check and come back to you,
I've seen a globe/ball or gate combination used alot here in Canadian gas plants. I dunno if it really matters who comes first. The globe is for throttling when the CV is out of service and the ball/gate is used to open/close. I dunno the reasoning for both. Maybe its simply a double block.
I've seen a globe/ball or gate combination used alot here in Canadian gas plants. I dunno if it really matters who comes first. The globe is for throttling when the CV is out of service and the ball/gate is used to open/close. I dunno the reasoning for both. Maybe its simply a double block.
I agree with Jop. Normally the Cntrl Valve stations that I have seen is a Control valve with two gate valves on either side and a Globe valve on the bypass. The Gate valves are to isolate the system when the Control valve is not workng while the Globe valve has to throttle the flow.
I agree with Jop. Normally the Cntrl Valve stations that I have seen is a Control valve with two gate valves on either side and a Globe valve on the bypass. The Gate valves are to isolate the system when the Control valve is not workng while the Globe valve has to throttle the flow.