2. OPERATION
IOM manual Tapflo Hose pumps
15
2.2.1.
Dry running
Although the pump is prepared for dry running it is important to have in mind that long
periods of dry run may cause damage to the wearing parts of the pump. What is more, an
empty pump should operate at low speeds
–
controlled by a frequency inverter.
2.2.2.
Dead head
The pump cannot operate with closed discharge valve. This may lead to pump malfunction
and cause injury to operators in the vicinity of the pump.
The discharge pressure can never exceed pump rated pressure.
2.2.3.
Optimization of the pump lifetime
➢
Continuous operation at higher frequency than 50 Hz will cause premature wear of the
components. As a general rule, we recommend to run
the pump at ±20% of the rated
frequency.
➢
When reducing the motor rotation speed, control the gear-motor surface temperature
if it does not exceed the nominal working temperatures stated by the gear-motor
manufacturer.
2.3.
Pump stopping
Turn off the motor to stop the pump. Close the discharge shut-off / regulation valve
immediately after. The reverse sequence is not recommendable, especially with larger
pumps or longer delivery piping. That is to avoid any problems due to water hammering.
It
is therefore advised to install a check valve on the discharge to protect the pump. If a
suction shutoff valve has been installed, it is advisable to close it completely after pump is
fully stopped.
The pump should be stopped by cutting of electrical power to the motor or frequency
inverter (if used
–
at 50 Hz cool down should be set to 5 seconds).
NOTE!
Never stop the pump by completely closing the discharge valve without motor shut
down.
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