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Closing valve
- Thread starter Ebbot
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OK, I suppose that Engineering is not your first language so I'll try to help define your question. First, both gas and liquid are "fluids". Let's assume that you meant to say "the media is liquid, but it will contain some gas".
Second, you didn't say what technology your valve was. If it is a rising stem gate valve, then a closing mechanism must turn the valve bushing dozens of times against varying torque, not insurmountable but also not trivial. If it is a ball valve or other 1/4 turn device then the options are much broader. If it is a solenoid valve then there are many electrical options.
Third, what do you mean by "high pressure"? Is it a 2 bar system that needs to shut in at 3 bar, or a 100 bar system that needs to shut in at 100.5 bar? Both the magnitude of normal operating pressure/temperature and the acceptable transient need to be known to answer your basic question.
If you'll clear up these questions I'm sure that the members here can help.
David
Second, you didn't say what technology your valve was. If it is a rising stem gate valve, then a closing mechanism must turn the valve bushing dozens of times against varying torque, not insurmountable but also not trivial. If it is a ball valve or other 1/4 turn device then the options are much broader. If it is a solenoid valve then there are many electrical options.
Third, what do you mean by "high pressure"? Is it a 2 bar system that needs to shut in at 3 bar, or a 100 bar system that needs to shut in at 100.5 bar? Both the magnitude of normal operating pressure/temperature and the acceptable transient need to be known to answer your basic question.
If you'll clear up these questions I'm sure that the members here can help.
David
The valve manufacturer can provide torque information required to close the valve. With some luck you have a quarter turn valve like a ball valve or butterfly valve that could be used with a single acting piston actuator. The actuator supplier should select the actuator based upon the minimum air supply (or other supply source) and about 25% safety factor. Single acting includes a spring return for a failure position. If a fail-safe position is not part of the concern, then consider a double acting actuator with no spring. You often find actuators by looking for "automated valve" or "shutdown valve" suppliers.
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- #4
Sorry about the diffuse question.
1. Yes, i meant liquid. (crude/water)
2. I don't have a valve at the moment. I'm trying to find out what kind of valve that best surves my purpose.
3. The line (1") will normally be ~1 bar, but when it gets pressurised (~5 bar) it should close.
1. Yes, i meant liquid. (crude/water)
2. I don't have a valve at the moment. I'm trying to find out what kind of valve that best surves my purpose.
3. The line (1") will normally be ~1 bar, but when it gets pressurised (~5 bar) it should close.
Suggestion 1.
Difficult to say, but for a pure liquid (particle free) a pilot or spring operated pressure reducing valve will close the inlet to the pipeline at a preset pressure, and open the inlet at a (lower, because of hysteresis) pressure.
Two problems to be solved
a) Particles must be filtered out before the control valve.
A multitude of commercial available solutions and filters exists.
b) Gas must be bled out before the valve. If the gas is air, or even by other gases, there is again a multitude of outlet valves and methodes.
How often will this pressure peak occur? Only safety measure or repetitive in some way?
Suggestion 2
Connect a pressure switch to the pipeline, pressure switch with flush face for contaminated fluids. If no available electrical supply arrange with battery operated solenoid valves to open when pressure switch reches preset value, to feed air from air accumulator to operate suitable air operated shutdown valves, placed where suitable.
If away from normal pressurized air resources the accumulatur could be refed with pressurized air from pump, nearest gas station or a separate small compressor.
It is not necessary to do anything with the fluid in the pipeline.
Suitable air operated valves: single or double acting ballvalves should work.
Difficult to say, but for a pure liquid (particle free) a pilot or spring operated pressure reducing valve will close the inlet to the pipeline at a preset pressure, and open the inlet at a (lower, because of hysteresis) pressure.
Two problems to be solved
a) Particles must be filtered out before the control valve.
A multitude of commercial available solutions and filters exists.
b) Gas must be bled out before the valve. If the gas is air, or even by other gases, there is again a multitude of outlet valves and methodes.
How often will this pressure peak occur? Only safety measure or repetitive in some way?
Suggestion 2
Connect a pressure switch to the pipeline, pressure switch with flush face for contaminated fluids. If no available electrical supply arrange with battery operated solenoid valves to open when pressure switch reches preset value, to feed air from air accumulator to operate suitable air operated shutdown valves, placed where suitable.
If away from normal pressurized air resources the accumulatur could be refed with pressurized air from pump, nearest gas station or a separate small compressor.
It is not necessary to do anything with the fluid in the pipeline.
Suitable air operated valves: single or double acting ballvalves should work.
1-inch, 1-bar NOP, 5 bar close is a very easy range to work on. If you have an air (or pressurized natural gas, or nitrogen) supply around 3 bar then Oil-Field pneumatic valves from Kimray are very reliable in rough service and reasonably priced. Rigging pilots to close one of these valves at a set pressure is done all the time. I've used pilots from Axelson for this function in rough service and they have worked very well.
If you don't have a pressurized gas source and do have electricity, then I would look at using a 1/4 turn ball valve with an electric actuator. The control logic is a bit more complex, but still pretty much mainstream.
David
If you don't have a pressurized gas source and do have electricity, then I would look at using a 1/4 turn ball valve with an electric actuator. The control logic is a bit more complex, but still pretty much mainstream.
David
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