Dragon Wholesaling 178 Series Інструкції з монтажу, експлуатації та технічного обслуговування - Сторінка 6
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Piping (General)
Note: Piping must not be connected to the pump until the grout has hardened and the foundation
and pump hold down bolts have been tightened.
Piping should be anchored independently of the pump and as near to it as possible. Pipe com-
panion flanges should line up naturally with pump flanges. Do not draw the pipe to the pump with
flange bolts.
Piping (Suction)
Properly selected and installed suction piping is extremely important to eliminate vibration and
cavitation in the pump. Vibration can cause packing problems or undue bearing loads.
The suction line should be equal to or larger than the pump suction. The capacity of a centrifugal
pump should never be adjusted by throttling the suction line.
A positive shut-off valve of a type to cause minimal turbulence should be installed in the suction
line to permit the closing of the line for removal of the pump for inspection and maintenance.
The suction line should be designed to eliminate any air pockets. The piping should gradually
slope downwards to the supply source to eliminate air pockets.
The suction line should have a straight section into the pump of a length equivalent to at least
two times its diameter; i.e. a 4 inch suction line should have a minimum 8 inch straight run. For
temporary hook-up when flexible hose is used, a non-collapsing hose is essential since the suc-
tion line pressure is often below atmospheric pressure. A collapsed suction line will result in
below average or complete loss of flow.
Piping (Discharge)
A positive shut-off valve should be located in the discharge piping to permit the closing of the line
for removal of the pump for inspection and maintenance.
All piping should be independently supported and accurately aligned. The pump must not support
the weight of the pipe or compensate for misalignment.
If operating conditions are not known with sufficient accuracy, it will be necessary to provide a
throttle valve in the discharge line to ensure that the pump operates at the design point.
If the pump is connected to a pressurized system, it is important to install a check valve between
the pump discharge and the throttling valve. The check valve will prevent back flow through the
pump. Back flow may cause the impeller to become loose on the shaft. A loose impeller will likely
result in mechanical damage and fluid leakage beneath the shaft sleeve.
PART II- PREPARATION for OPERATION
Initial Lubrication
Standard pumps are shipped with oil in the reservoirs. The oil level must be checked and oil
added if necessary before operating the pump. A good grade of SAE 10W30 oil can be used.
The air vent should be kept clean to prevent pressure build-up due to heating that occurs in nor-
mal operation. There is a dipstick that shows the correct oil level. If vertical operation or grease
lubrication of the bearings is preferred, there are plugs in the front and rear bearing caps that can
be removed and replaced with grease fittings.
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