䞉
Attach a foot valve with a strainer to the end of the suction pipe to prevent entry of foreign
objects. Immerse the foot valve in water and set it at a depth of at least twice the diameter of the
pipe from the surface of water to prevent the suction of air. In addition, ensure that it is set
above 500 mm or more from the bottom of water.
(11) Attach a sluice valve and a check valve to the discharge pipes. If water hammer may occur, attach
a buffer type check valve.
(12) If there is an upward curve in the discharge pipe, ensure that air can be vented from the section.
(13) If two or more pumps are used for negative suction pressure, every pump should have its own
separate suction piping.
(14) If you take heat insulation measures for the pump, be sure to avoid the motor section. Otherwise,
the motor may heat up and ignite. Furthermore, since the mechanical seal needs to be replaced
periodically, install detachable insulation for it.
Warning
Never install heat insulation to the motor section. Otherwise, the motor may heat
up and ignite.
(15) On completion of the piping work, be sure to clean the inside of the receiver tank. Pay attention
not to contaminate the system with foreign matter.
Caution
䞉
Properly install the foot valve vertically. If the valve is not vertical, it does not
open or close properly, which comprises the function of the foot valve.
䞉
Immerse the foot valve in water and set it at a depth of at least twice the
diameter of the pipe from the surface of water to prevent the suction of air. In
addition, ensure that it is set above 500 mm or more from the bottom of water.
Caution
If two or more pumps are used for negative suction pressure, every pump should
have its own separate suction piping. Otherwise, air may be sucked from the
inactive pump during single-pump operation, thus preventing water from being
pumped.
