When the centrifugal pump starts, there is no water in the outlet pipeline of the pump, so there is no pipeline resistance and lifting height resistance. After the pump starts, the pump head is very low and the flow rate is very large. At this time, the output of pump motor (shaft power) is very large (according to the pump performance curve), which is easy to overload, which will damage the pump motor and circuit. Therefore, the outlet valve should be closed when starting to make the pump run normally.
(1) close the inlet and outlet pressure (or vacuum) meters and water outlet valves (if there is a bypass pipe, it should also be closed at this time).
(2) Always pay attention to the power reading of the prime Mover and the vibration of the pump during the starting process, the vibration number should not exceed 0.06 mm, and the measuring part is the bearing seat.
(3) Check whether the leakage of shaft seal meets the requirements, and the leakage of sealing medium shall not exceed the following requirements: for mechanical seal, 10 drops /min of light oil and 5 drops/min of heavy oil; For packing seal, light oil 20 drops /min, heavy oil 10 drops /min.
(4) Start the motor after turning is no problem; Start the motor (it is best to start the operation after inching and confirming that the pump turns correctly), and then open the inlet and outlet pressure (or vacuum) meters. When the pump reaches normal speed and the meter indicates the corresponding pressure, slowly open the outlet valve and adjust it to the required working condition.
(5) When the pump outlet pressure and motor current are normal, gradually open the pump outlet valve, closely monitor the motor current, and control the current within the red line to prevent the motor from being overloaded and burning down;
(6) Check whether the outlet pressure indication is normal and the lubrication condition is in good condition;
(7) Sealing condition: the mechanical seal shall be free from leakage and heating, and the packing seal shall be in continuous dripping state.
(8) Check whether the cooling system operates normally;
(9) Check whether the vibration value and bearing temperature of the pump are within the allowable range. The vibration value shall conform to ISO 2372 and ISO 3495 standards. The bearing temperature should meet the following requirements: for forced lubrication system, the temperature of bearing oil should not exceed 28℃, and the temperature of bearing metal should be less than 93℃; For oil ring lubricating oil or splash lubricating system, the temperature rise of oil pool shall not exceed 39℃.
(10) Pay attention to the outlet flow and pressure of the pump at any time, and judge the blockage of the filter according to its changes. When the blockage is serious, stop the pump immediately.
(11) seriously and properly handle the problems in operation, and make detailed records, and at the same time cooperate with other positions to do a good job in the aftermath of operation.
(1). Check the heating of pump and motor (the temperature rise of bearing should not exceed 75℃) and the oil supply of oil level gauge. (generally, after every 1500 hours of operation, all lubricating oils should be replaced once).
(2) The suction valve cannot be used to adjust the flow rate to avoid cavitation.
(3) The pump should not run continuously at a flow rate lower than 30% of the design flow rate. If it must run continuously under this condition, a bypass pipe should be installed at the outlet to discharge the excess flow rate.
(4). Pay attention to whether there is any noise in the pump operation. If any abnormal state is found, it should be eliminated in time or stopped for inspection.
(1). Slowly close the gate valve of the spit outlet pipeline (if the pump is used under the condition of backward flow, close the gate valve of the suction pipeline), and close the switches of various instruments.
(2) Cut off the power supply and turn off the motor.
(3). If the seal adopts external liquid introduction, the liquid introduction valve should also be closed.
(4) If the ambient temperature is lower than the freezing point of the liquid, drain the liquid in the pump to prevent frost crack.
(5). If you don't use it after stopping for a long time, apart from draining the corrosive liquid in the pump, all parts should be disassembled and cleaned, especially the sealed cavity. It is best to remove the pump, clean it, and then reinstall it. Besides oil-coated antirust treatment and sealing the inlet and outlet of the pump, it should also be checked regularly.
