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I N S T A L L A T I O N , O P E R A T I O N A N D M A I N T E N A N C E M A N U A L
It is advisable to increase the size of both suction and discharge pipes at the pump
connection to decrease the loss of head from friction,
Where reducers are used, eccentric reducers are to be fitted in suction lines and
straight taper reducers in discharge and vertical lines. Misuse of reducers may
cause the formation of air pockets in the pipe and thus preventing the correct
operation of the pump.
The suction pipe should be as short and direct as possible. Where suction lift is not
very high, it is advisable to use a foot valve. Horizontal suction line must have a
gradual rise to the pump.
Typical suction pipes layouts, "Correct and Incorrect", are shown in figures as
below.
The pump must never be throttled by the use of a valve on the suction side if the
valve provided. Suction valves should be used only to isolate the pump for
maintenance purpose.
The discharge pipe is usually provided by a non-return valve or check valve and a
discharge gate valve as shown in below picture. The check valve is to protect the
pump from excessive back pressure and reverse rotation of the unit and to prevent
back flow into the pump in case of stoppage or failure of the driver. The discharge
valve is used in priming, starting and when shutting down the pump.
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D E C C A N I N D U S T R I E S
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