Centrifugal pump operation and maintenance are critical issues. Centrifugal pump is a very critical equipment in many sectors like domestic, public, and industrial plants. Centrifugal pump is a needful machine in chemical, petrochemical, and refineries. Chemical, petrochemical and refineries are energy-intensive industries. They have to run continuously round the clock. Centrifugal pumps mainly handle water and various liquid chemicals in chemical plants. We will discuss the centrifugal pump operation and maintenance of water pumps. In chemical plants, many processes generate heat during the process. This process heat is to be taken away from the equipment, to run the process and equipment safely and efficiently. To take away the process heat, cooling water is circulated through the equipment. The circulation of water in the plant is carried out by a centrifugal water pump continuously.
CENTRIFUGAL PUMP OPERATION
Centrifugal water pumps are to be operated carefully. Standard Operating procedures for the centrifugal pump to be followed strictly. Any wrong step in the operation of the pump may cause hydraulic and mechanical damage to the pump. It may reduce its efficiency. Centrifugal pump operation and maintenance to be carried out through trained personnel.
STEPS TO START THE PUMP
To start a pump following points to be taken into account:
(1) Hold the coupling of the pump and rotate manually. Ensure that the pump and motor are free to move.
(2) Open the pump suction valve to vent out water through the casing vent. Ensure that the pump casing is filled up with water.
(3) Give a power jerk to the motor and ensure, the correct direction of rotation of the pump. Observe this from the motor side.
(4) If the direction of rotation of the pump is correct, then switch on the power.
(5) See the discharge gauge pressure of the pump. Slowly open the discharge valve of the pump for the required flow of the fluid. Note down load of the electrical motor.
(6) Now keep the pump running.
PUMP PARAMETERS, TO BE OBSERVED
During the running of the pump following parameters to be observed. To ensure the efficient and trouble-free running of the pump:
(1) The suction pressure.
(2) The discharge pressure.
(3) Discharge flow.
(4) Pump speed or motor RPM.
(5) Motor power consumption.
(6) Vibration in the pump.
(7) Bearing temperature
(8) Oil level in the pump housing.
To stop the pump, the following steps to be followed:
(1) Close the discharge valve of the pump slowly.
(2) Switch off the pump motor.
(3) Closed the suction valve of the pump.
(4) If the pump is required to be kept idle for a long time, drain the pump casing completely.
PUMP HEALTH CHECK-UP PLAN
To run the pump continuously without failure, following pump health check-up plan to be followed:
(1) Pump daily check-up
(2) Pump periodic check-up (quarterly)
(3) Pump annual check-up
PUMP DAILY CHECK UP
To log down the following parameters daily.
(1) Discharge pressure.
(2) Bearing housing oil level through the sight glass.
(3) Level in the constant oiler cup.
(4) Bearing temperature.
(5) Abnormal noise and vibration in the pump.
(6) Stuffing box shaft-packing leakage should not be more than dropwise.
(7) Any leakage in the pump piping and flanges.
PUMP QUARTERLY CHECK UP
(1) Pump shaft alignment to be checked. Realign if required.
(2) Bearing oil to be changed quarterly.
(3) Check the foundation bolts of the pump base plate. Get tightened if found loose.
PUMP ANNUAL CHECK UP
Every year the following check-up in the pump to be done:
(1) Pump shut off pressure.
(2) Pump discharge pressure development.
(3) Pump flow rate and efficiency.
(4) Pump power consumption.
Analyze the parameters logged down if the pump is not running efficiently then plan the shutdown for maintenance of the pump.
PUMP MAINTENANCE, SCHEDULE OF ACTIVITIES
(1) Remove the pump from the pipelines.
(2) Dis mental the pump and inspect all internal parts of the pump, like a shaft, shaft sleeve, impeller, etc. Do the replacement of the part if wear and tear are found on the parts.
(3) Check the bearing oil for metallic contamination. Replace the bearing of the pump if metal particles are found in the oil.
(4) Check the thoroughness of the pump shaft, take corrective action.
(5) Check the shaft sleeve condition for corrosion and erosion, if found replace it.
(6) Repack the stuffing box packing. If packing is found hard
(9) Check the impeller for any corrosion and erosion signs, replace it if required.
(10) Pump coupling bolts to be checked for any cracks, bending, or thread damage, if required replace them.
(11) Motor coupling holes to be checked, if any oblong in the holes is found replace the coupling.