BYPASS REQUIREMENT IN GATE VALVE
BYPASS REQUIREMENT IN GATE VALVE
(OP)
In which scenarios we will prefer to provide bypass for GATE VALVE/GLOBE VALVE...WHY? THANKS IN ADVANCE
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BYPASS REQUIREMENT IN GATE VALVE
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BYPASS REQUIREMENT IN GATE VALVEBYPASS REQUIREMENT IN GATE VALVE(OP)
In which scenarios we will prefer to provide bypass for GATE VALVE/GLOBE VALVE...WHY? THANKS IN ADVANCE
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RE: BYPASS REQUIREMENT IN GATE VALVE
Other isolation valves are, in general, not suited for large differential pressures / stopping or starting flow.
Some gate valves are better than others depending on the fluid, differential pressure and location and types of seals.
Bypasses are more common on gas systems which can generate very large velocities on opening / closing but usually only where there is a significant differential pressure or where there is a big volume on the lower pressure side. For short pipe lengths it is often not required.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: BYPASS REQUIREMENT IN GATE VALVE
Control valves are often blocked and bypassed using a block valves and a manual throttling valve should the control valve need to be taken out of service temporarly for maintenance purposes.
RE: BYPASS REQUIREMENT IN GATE VALVE
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: BYPASS REQUIREMENT IN GATE VALVE
RE: BYPASS REQUIREMENT IN GATE VALVE
http://www.spxflow.com/assets/pdf/mj-1761-us_expan...
RE: BYPASS REQUIREMENT IN GATE VALVE
I agree - expanding wedge gate valves are much better. However, when you open against high pressure, you still get some impact on the valve as the seals lift off and the gate starts to move.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: BYPASS REQUIREMENT IN GATE VALVE
RE: BYPASS REQUIREMENT IN GATE VALVE
RE: BYPASS REQUIREMENT IN GATE VALVE
So, in my experience, what I've seen is a small line as a bypass around a facility inlet to avoid having someone crack open that big inlet valve too much when starting up.
A bypass around a globe valve, haven't seen that except if the globe valve is automated, in which case you would also put isolation valves around that globe control-valve so you can work on it if you need to. Change the trim, etc. So in the meantime, you'd have a bypass around the "valve station", usually using a globe valve also, but smaller, that someone could adjust manually while the control valve is out of service.
Are you looking at a drawing with such a bypass, or did you see one in the field and were curious, or did someone ask you to put a bypass in and you weren't sure why?
RE: BYPASS REQUIREMENT IN GATE VALVE
1. To fill/pressure the downstream side of an isolation valve before opening it. This means the pressure will equal over the valve gate and making it much easier to open. Only works if the downstream side is a closed system.
2. An open by-pass around a control valve gives a minimum flow when the control valve is closed. Stops having to use the larger valve at small opening.
RE: BYPASS REQUIREMENT IN GATE VALVE
There's an MSS standard that covers relative sizes and orientations. (Sorry - don't have my MSS standards handy)
Regards,
donf
RE: BYPASS REQUIREMENT IN GATE VALVE
Having said that I can't see why the expanding wedge gate should not be classified as a DIB valve and allow operations when you activate the body bleed. Otherwise why bother?
I always fight against bypasses around control valves unless you duplicate it. If it's there to control something then installing a bypass, gate valve or manual valve simply defeats the whole purpose of the valve in the first place. I've fought this many times in HAZOPS and nearly always won the argument.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: BYPASS REQUIREMENT IN GATE VALVE
RE: BYPASS REQUIREMENT IN GATE VALVE