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Flow rate loss due to pressure loss

  1. Oct 9, 2014 #1
    If I'm losing 30 psi every 20 seconds at a pump, how many gallons am I losing in that time frame? I don't really have a lot of information to go on, which is frustrating. I know the diameter of the pipe is 8" and there's a total length of 500 feet of the pipe. With this info I'm having trouble finding a good starting point on figuring this out. I do t know if it's being losses over a distance or just at a point. Can someone point me in the right direction? Feels like I'm missing something obvious.
  2. jcsd
  3. Oct 9, 2014 #2


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    Yep, as it is it's unclear what is even going on; you need to explain the situation properly. Diagrams help.
  4. Oct 10, 2014 #3


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    You are going to have to explain more about what the application is and what your end goal is? Pressure loss over time means you are losing stored energy somewhere, what is the pipe transferring water from/to?
  5. Oct 10, 2014 #4
    Yea, rarely in a pump system do you have to deal with delta-psi / min, or any variation thereof. Certainly systems change in their overall pressure (and therefore flow rates, or vice versa) but a progressive drop in pressure, where there wasn't one before, indicates that something is amiss with your system. What that could be is anyone's guess at this point. Could be a faulty valve (perhaps with a mis-programmed or buggy control loop?) somewhere, could be a slipping coupling in the pump, could be issues with pump seals and internals, could be an issue with the suction side (if it's a tank it could be that the air spaces are not replenishing quick enough and you are drawing a vacuum, which is dropping your NPSHa. Lots of stuff.
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