Centrifugal pump operation process

Working principle of centrifugal pump

Centrifugal pump, also known as centrifugal pump It is a pumping machine that utilizes the centrifugal motion of water. Before starting, the pump should be filled with water. The rotating impeller after starting drives the water in the pump to rotate at high speed, causing the water to undergo centrifugal motion and be thrown outward and pressed into the outlet pipe. After the water is thrown out, the pressure near the impeller decreases, forming a low-pressure zone near the shaft. The pressure here is much lower than atmospheric pressure, and the external water, under the action of atmospheric pressure, rushes open the bottom valve to enter the water inlet The pipe enters the pump. The rushing water is thrown out again during the high-speed rotation of the impeller and pressed into the outlet pipe. The impeller rotates continuously at high speed driven by the power machine, and water is continuously pumped from low to high.

Inspection items before starting the centrifugal pump

(1) Add lubricating oil: There should be at least one-third to two-thirds of the oil level in the center line of the sight glass or the constant level oil cup, and the mechanical, instrument, and electrical equipment of the pump should be checked for completeness;

(2) Filling pump: Close the inlet valve, open the outlet valve and vent valve, and close the exhaust valve when liquid is seen; Turn the pump after filling;

(3) Jog: Check if the rotation direction is correct (the rotation of the pump rotor must be in the same direction as the arrow on the suspension).

Operating steps when starting a centrifugal pump

(1) Open the inlet valve to the fully open position and confirm that the outlet valve is fully closed;

(2) Confirm that all cooling, heating, and flushing pipelines are started and stable;

(3) Start the motor and slowly open the outlet valve after setting the speed, adjusting until the required flow rate is obtained; (The minimum flow rate cannot be less than the minimum flow limit);

(4) Check and confirm the sound and vibration of the pump operation, as well as the temperature of the bearing seat and motor, and confirm that there are no abnormal leaks or odors;

(5) Confirm that the indications on each pressure gauge are stable.

Switching operation of the pump

(1) Check the backup pump and turn it to confirm that the machinery, instruments, electrical appliances, cooling and lubricating oil systems are in good condition, and the equipment is ready for start-up;

(2) Open the inlet valve of the standby pump and start the standby pump motor;

(3) Slowly open the outlet valve of the standby pump;

(4) Gradually close the outlet valve of the running pump, confirm that the outlet valve of the running pump is fully closed, and open the outlet valve of the standby pump to the appropriate position;

(5) Stop the motor of the pump and close the inlet valve;

(6) Check and confirm that the sound, vibration, and temperature of the bearing seat and motor of the running pump are normal, and confirm that there are no abnormal leaks or odors.

Key points for operating centrifugal pumps

(1) If the pump is damaged due to empty transfer, the flow rate must be adjusted by the outlet valve, and the inlet valve cannot be used to adjust the pump flow rate;

(2) After starting the motor, the outlet valve of the pump must be opened for a short period of time, otherwise it may cause heat accumulation and damage to the pump;

(3) After the pump stops running, the supply of cooling water can only be stopped after the pump has completely cooled down;

(4) Immediately stop the pump in the following situations: severe leakage, abnormal vibration, odor, sparks, smoke, impact, continuous high current.

Daily maintenance and upkeep of centrifugal pumps

(1) Timely check and inspect the shaft seal and all joint sealing surfaces for leaks;

(2) Check whether the cooling system and sealing lubrication system are smooth, and whether the pressure and temperature are within a reasonable range;

(3) Check the smoothness of operation and whether there is vibration;

(4) Check if the coupling, safety cover, and base bolts are loose;

(5) If the vehicle is parked for a long time, the materials in the system should be discharged thoroughly. When the temperature is low, the anti freezing and anti condensation conditions should be checked.