The 5 Hydraulic Troubleshooting Tools You Don't Have
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- čas přidán 2. 08. 2024
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Great info. What a great demonstration of the variable displacement pump. You did such a great job. Thank you
Thanks. Really interesting info
Thanks, Michael!
EXCELLENT WELL DETAILED EXPLANATION
Thank you for your kind comment, Felix!
Great video Sir
DGB Thanks!
Bien.
How do you prevent pressure shock when measuring pressure upstream?
Thank you for your question! I presume you are talking about protecting your expensive gauge from the shock in the system. The gauge is one of your most valuable troubleshooting tools, so it is crucial that it be taken care of. There are two common ways to do this. The best is a gauge isolation valve. This is a three-way pushbutton type valve that releases pressure from the gauge whenever it is not actively being read. You push the button and read the gauge, then when the button is released, pressure is drained to tank and the gauge drops to 0. Second best is a "snubber". This is a small, variable orifice flow control that you crack open when reading the gauge. By metering the flow to the gauge, spikes are eliminated. The gauge response is tempered, keeping it from damage while allowing the pressure to be read. Once you are finished monitoring the pressure, close the snubber, locking pressure in the gauge and isolating it from the system. Hope this helps!
Thanks for the reply, although what I meant was if pressure testing were to be done near to the pump, one would have to shut off the valve nearest to the pump yes? In that case, pressure acceleration would be extremely quick and likely destroy the pump, so how does one test for pressure near the pump safely?
OK, I think I see what you mean now. It is true that, in order to get a reliable pressure setting, the pump needs to be deadheaded. This is best done by blocking flow to everything in the system EXCEPT the system relief valve. If you are checking pressure with a fixed displacement pump, the pressure in the system will be determined by the relief valve. If your purpose here is to test the condition of the pump, you should also have a flow meter installed either upstream of the relief valve or in the relief valve tank line. Check the amount of flow first with the relief valve adjusted at a very low pressure. In this case, even a badly worn pump will deliver all or nearly all of its rated flow. Now, begin to slowly increase the pressure while monitoring the flow meter. If the pump is any good, there will be little if any change in the flow once you have reached normal system pressure. If, however, the flow drops more than ten percent, the pump is becoming worn and will soon need to be replaced (depending, of course, on the system flow requirements).
If you are checking a variable displacement pump, the procedure is the same except that the pressure adjustment on the pump must be higher than the highest setting on the relief valve. This ensures that the relief valve is determining pressure rather than the pump, giving a reliable indication of the pump condition.
In no case should a system be operated WITHOUT a relief valve. I have seen system designs with no relief valve, operating on the assumption that the pump regulates pressure so there is no need for a relief valve. This is dangerous, because the pump's pressure compensator valve can stick either open or closed. Depending upon the pump design, one way will keep any pressure from building in the system, the other will keep the pump at full stroke all the time, causing it to perform as a fixed displacement pump.
Hope this answers your question!
Thanks for the detailed answer man I learnt alot. Have a great one.