Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

2 identical parallel centrifugal pumps ?

  1. May 28, 2010 #1
    2 identical parallel centrifugal pumps ???

    hello everyone i have a very confusing problem with a cold water system sonsists of 2 identical centrifugal pumps their position is under the tank so there is always a +ve suction head then those pumps takes water from the tank and deliver it to a very simple pipes network to acheive the required processes with the water such as cooling gases via heat exchangers and this water is used also as feed water to some other water systems but to make cooling """other words """"""""" closed circuit

    so the problem now is that some times when i operate one pump i found out that there is no water at all in the circuit althoug i can see the vortex of suction in the tank
    also all of the heat exchangers are okay no mixing
    i dont know where does the water go ???


    and when i work both of them everything is okay
    but each pump is 100 hp and 196 m3/hr and has a head of more than 100 mt
    so can this be an impeller problem of the pump ???
    or whats the problem i dont know ??????
     
  2. jcsd
  3. May 29, 2010 #2
    Re: 2 identical parallel centrifugal pumps ???

    its a very big problem i know can anyone help me ??????????
     
  4. May 29, 2010 #3
    Re: 2 identical parallel centrifugal pumps ???

    Is it possible that the flow is going back to the tank via the second pump? If you have isolating valves try shuting off the non-running pump.
     
  5. May 29, 2010 #4
    Re: 2 identical parallel centrifugal pumps ???

    well i have also check those valves
     
  6. May 29, 2010 #5
    Re: 2 identical parallel centrifugal pumps ???

    but u know there is a phase in the flow in pipes nammed syphon ?? can it be this problem ???
     
  7. May 29, 2010 #6
    Re: 2 identical parallel centrifugal pumps ???

    but the pump head is very high for this application
     
  8. Jul 10, 2010 #7
    Re: 2 identical parallel centrifugal pumps ???

    Dear MR or Modam:

    I think you dont have the CHECK VALVE in the discharg of pumps. yor prolem hapend in the time tath you dont close the shoted pump discharg valve .
    the water circulate inthe shoted pump .and it cuse the rotation of shoted pump in on usual rotation side and probably cuse to open the impeller nut of shoted pump.

    close the shoted pumps valves to solve the problem.


    Mortaza Lotfi


    lotfiplan@hotmail.com
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook