The suction pipe should be sized to obtain a flow velocity of 4 to 7 feet per second. Changes in flow di-
rection should be avoided wherever possible, especially near the pump suction. A reducer at the pump
suction flange to smoothly accelerate and stabilize flow into the pump is desirable.
Refer to the nearest Goulds representative for further information.
Installations with pump above source of supply - suction lift
1.
Keep suction pipe free from air pockets - See
.
2.
Piping should slope upwards from source of supply.
3.
No portion of piping should extend above the pump suction nozzle.
4.
All joints must be air tight.
Installations with pump below source of supply - suction head or flooded suction
1.
A gate valve should be installed in the suction line to permit dosing of the line for pump inspec-
tion and maintenance.
2.
Keep suction pipe free from air pockets.
3.
Piping should be level or slope gradually downward from the source of supply.
4.
No portion of the piping should extend below pump suction flange.
5.
The size of entrance from supply should be no smaller than the suction pipe.
6.
The suction pipe should be adequately submerged below the liquid surface at the source of sup-
ply.
2.8 Piping - discharge
1.
Gate and check valves should be installed in the discharge line. The check valve should be locat-
ed between the gate valve and pump to permit inspection of the check valve. The gate valve is
required for priming, regulation of flow and for inspection and maintenance of the pump. The
check valve is required to prevent reverse flow through the pump when the driver is turned off.
2.
Increasers, if used in discharge line, should be placed between the pump and check valves.
3.
If quick-closing valves are installed in the system, cushioning devices should be used to protect
the pump from surges and water hammer.
2.9
Connection of piping
Connect suction and discharge piping to the pump. Rotate pump shaft several times by hand to be sure
there is no binding and that all parts are free. Recheck alignment.
NOTICE:
On non-metallic pumps, use gaskets which are suitable for the flanges. PTFE envelope style is
recommended.
2.10 Rotation
Serious damage may result if pump is run in wrong direction. Before coupling is connected, the motor
should be wired and the direction of rotation checked. The direction of rotation is marked on the pump.
Make sure driver rotates in the same direction.
2.8 Piping - discharge
20
Model 3415 Installation, Operation, and Maintenance Manual