The best way is to enter a relief valve size into the similation and see if it will flow enough to alleviate the pressure and keep the line below its allowable pressure. You can also note the volume of fluid relieved and size your relief tank and reinjection system accordingly.
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"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)
If you are trying to employ a conventional pressure relief valve (PSV) to "relieve" the effects of a water hammer, you can forget it. It simply will not work - primarily because it isn't designed for that service and doesn't even come close to mitigating the hammer effect.
The standard pressure relief device (as covered in API 520 and API 521) cannot physically react fast enough to "relieve" the oncoming liquid hammer and resulting hydraulic pressure rise fast enough. It would probably shatter before it even began to open.
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"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)
BigInch,Montemayor, Artisi
Thank you very much. I have looked at the web links and information you sent me and much appreciated. If I use this valve (surge relief valve in the web link you sent me), do i still need to use check valves on the delivery side of each pump? or else, this valve will do the purpose also for the normal check valve?
If I have four pumps in parrale, and I want to protect them working agianst closed valve, can i use normal safety relief valve? is it better to put one vlve per each pump or only one large size valve on the main discharge headrer?
I might prefer something like the recycle valves that Yarway makes, rather than relief valves.
I'd guess it would probably be better to put one smaller sized valve in the discharge line of each pump, rather than a big one on the header that would have to deal with a wide flowrate range.
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"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)
BigInch
Thank you very much. For the recycle vlves, do you mean they work outmatic or manually, do they call them safety valves? and for their discharge pipe, can we connect it to the suction side of the pumps?
Thanks
You might want to consider putting a rising temp switch on the pump if your afraid of it running against a closed valve. Its a simple install and cheap insurance.
Asking how to survive a hammer is the wrong question. Avoid causing it in the first place. Water is a very rigid fluid, treat it with respect.. 1.Use a VFD or softstart on the pump.
2.Close valves at a controlled rate.
3.Use a surge cushion (accumulator) as a last resort.
Thank you every one
I have seen sometime they use a safty valves on the discharge side of each pump, are those valves work to protect the pumps againest closed valves or buildup of high pressure in the system? do they recommend them to be one valve or multiple vlavles on each pump dilevery? Can the leading of those valves be connected to the main suction header?
Thanks
Safety valves on the pump discharges are to protect the downstream piping and system from overpressure, if the pump is capable of generating more pressure than the system is capable of withstanding.
Thanks TenPenny
So I understand the main reason behind using the safty valves on the dischage is to protect the piping system not the pumps. if that is te case, How do these valves look like, do they call them safty relief valves? Are they the same ones used for reducing water hammer? i gess not. Can I use one of these safty valves on the main valve on the main header? instaead of multiple valves,
Thnaks
Yes you could use one, two, or more. Depends on if you can shut down your system while you remove, repair, or test one safety valve, or if you can't stop and can't safely pump without a working safety valve at all times. Two or more would allow you to do maintenance on one while continuing to pump as usual.
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"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)
aoliman5
There are many assumptions to make on your application, but I would suggest you look in to a surge dampner. Many differnt types and materials of construction to consider based on the pressure and process fluid. Based on the pressure spike anticipated and the piping systems ability to handle the pressure spike, you may set a releif valve just under your maximum pressure point your system can handle. The surge suppresor will soften the peek of the spike with out reduction of fluid in process. The releif valve will allow excessive pressure out of the system.
I would try to think of the system as a p1v1=p2v2 relationship. proportional lost in pressure based on loss of volume. Pick your releif valve based on the ability of the valves Cv or Flowrate. The larger the valve, the faster it can expel capacity/pressure.
Good Luck
