User Manual
15
2. IMPORTANT OPERATION STEPS
1) Check before the test run
a) Assurance the level of liquid. The liquid level in the storage tank must be
maintained at more than 3 meters, the inlet pressure conforms to the provisions of
the pump nameplate.
b) Before putting pump body into tank pump vacuum jacket, should first connect
motor and inverter wiring, 3 wires were insulated joints.
c) Set parameters of converter, reference parameters of motor pump nameplate.
d) Piping accessories such as inlet and outlet pressure gauge, import / export valve
are correct installed and degreasing treated, according to the pump flow chart.
e) Use sufficient nitrogen to replace the inside air of whole device including the
pump tank, pump , motor, tank and pipeline system, to ensure the system without
water and all the compounds containing oxygen.
2) Cryogenic pump fully Pre-cooling
The cryogenic pump system by oxygen replacement after the completion of the work,
slowly open the inlet valve and return valve, pre-cooling for at least 15 minutes, to
observe the return air temperature. After ensuring the pump cooling had finished,
half open return valve, slowly open the outlet valve to the opening degree of 1/3.
3) Start the pump
After check the startup conditions have completely, start the pump at the rated speed
65%. If there is abnormal sound, should stop immediately and check. If the pressure
raise up after starting pump, adjusting the outlet valve opening and adjust the
frequency, so that the pump to normal working condition.
If the pump can’t increase pressure within 10 seconds (pressure gauge without
swinging back and forth), need to immediately stop the pump and cooling pump for 3
minutes, and then restart the pump. If pump can’t increase pressure twice again,
need to change steering pump via the frequency converter then restart.
4) Stop the pump
After stopping the pump, close the inlet, outlet valve, and open the valve, release
the pressure of pump tank.
After the pump is stopped firstly should ensure that the safety valve of the pump can
work normally. After the pump is stopped, must maintain a certain slight pressure in
pump tank. If the vent valve located on pump tank open for a long time, after pump
pressure drop to atmospheric pressure, because the pump tank and the pump body
is still cold, moisture in the air will enter the pump tank, lead to them in the pump
body condenses into drops of water. These attached to the bearing, impeller, water,
are relatively closed, it is difficult to purge out. The next time, water will be frozen into
the ice of a cryogenic liquid, the bearing can’t operate normally, it’s serious that this
still can burn out the motor.