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    kensingtonm's Avatar
    kensingtonm Posts: 4, Reputation: 1
    New Member

    Oct 10, 2006, 07:12 AM
    Why is it always advisable to start a pump against a closed valve?
    bhayne's Avatar
    bhayne Posts: 339, Reputation: 4
    Full Member

    Oct 12, 2006, 03:41 PM
    I'm not mechanical but I believe you are talking about reciprocal pumps with full voltage starters. This is typical for these pumps because for short periods they can operate without any discharge. Other types of pumps would either stall out or cause damage.

    Reciprocal pumps also need to be primed if they start at negative pressure. To reduce the negative pressure, sometimes the valve upstream is closed until the pump is primed.

    Also, depending on the type and length of pipe, water hammer is removed by starting the pump with a closed valve and opening it slowly. In this case, a soft start can remove need to close the valve before starting.
    anagat's Avatar
    anagat Posts: 1, Reputation: 1
    New Member

    Oct 18, 2006, 07:59 PM
    How do you size tanks for booster pumps
    kensingtonm's Avatar
    kensingtonm Posts: 4, Reputation: 1
    New Member

    Oct 18, 2006, 10:37 PM
    As I understand , Booster pumps are normally installed in an existing pipeline to boost/increase capacity of the pipeline.I'm not sure what "tanks" you are referring to.Are these storage tanks where the booster pumps are pumping to or something else?
    nileshgem's Avatar
    nileshgem Posts: 1, Reputation: 1
    New Member

    Oct 23, 2006, 01:29 AM
    I am working in printing industry. Over here have centralize compressor. But now we want to develop centralise vacuum system for our plant, want somebody who can design and develop system for us. Let me known who can help us in above. We are placed in INDIA
    caibuadday's Avatar
    caibuadday Posts: 460, Reputation: 10
    Full Member

    Nov 1, 2006, 05:19 PM
    Quote Originally Posted by kensingtonm
    Why is it always advisable to start a pump against a closed valve?
    With the valve open, a lot of mass will move at start up, will cause the pump, piping to shift, and connections may( will) break
    JoeWong's Avatar
    JoeWong Posts: 2, Reputation: 1
    New Member

    Apr 25, 2007, 01:36 AM
    Closed valve start-up is relate to motor rating of centrifugal pump.

    Pump shaft power is a function of head (H) and flow (Q). Open valve start-up will result large flow passing through centrifugal pump (as backpressure is yet to developed) and causing pump motor trip.

    Open valve start-up may required larger motor... :)

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