(1) The pump shaft is broken.

The pump shaft of the CQB magnetic pump is made of 99% alumina porcelain. The main reason for the fracture of the pump shaft is that the shaft is twisted due to the dry running of the pump and the dry grinding of the bearing. When the pump is disassembled for inspection, it can be seen that the bearings are severely worn. The main way to prevent the pump from breaking is to avoid dry running of the pump.


(2) The bearing is damaged.

The bearing of CQB magnetic pump is made of high-density carbon. If the pump is cut off or there are impurities in the pump, the bearing will be damaged. If the coaxiality requirements between the inner and outer magnetic rotors of the cylindrical coupling are not guaranteed, it will directly affect the life of the bearing.


(3) The pump cannot pump liquid.

The failure of the pump-to-pump liquid is the most common failure of the pump, and there are many reasons for it. First of all, check whether there is any air leakage in the suction pipe of the pump, check whether the air in the suction pipe is discharged, whether the amount of liquid poured into the pump is sufficient, whether there is any debris in the suction pipe, and check whether the pump is reversed (Especially after the motor has been replaced or the power supply line has been overhauled), attention should also be paid to whether the suction height of the pump is too high. If you still can't solve the problem through the above inspections, you can disassemble the pump and check to see if the pump shaft is broken. You should also check whether the moving and static rings of the pump are intact, and whether the entire rotor can move a little axially. If the axial movement is difficult, check whether the carbon bearing is too tightly combined with the pump shaft.


It is worth noting that the pump has been repaired several times and no problem can be found. Attention should be paid to whether the magnetic coupling is working normally. Bearings, internal magnetic rotors and spacers will generate heat during operation, which will increase the working temperature, reduce the transmitted power on the one hand, and cause great trouble to the pump that transports easily vaporized liquid. The power transmitted by the magnet steel is a continuous decline curve with the increase of temperature. Usually, the decline in the transmission capacity of the magnet steel is reversible below the working limit temperature of the magnet steel, but it is irreversible above the limit temperature, that is, the cooling of the magnet steel Afterwards, the lost transmission capacity can never be regained. Under special circumstances, when the magnetic coupling slips (out of step), the eddy current heat in the spacer will increase sharply, and the temperature will rise sharply. If it is not handled in time, it will cause demagnetization of the magnetic steel and make the magnetic coupling invalid. Therefore, the magnetic pump should be designed with a reliable cooling system. For the medium that is not easy to vaporize, the cooling circulation system generally draws the liquid flow from the outlet of the impeller or the pump outlet, and returns to the suction port through the bearing and magnetic transmission part. For the medium that is easy to vaporize, a heat exchanger should be added or the liquid flow should be led out of the pump. For storage tanks, avoid heat returning to the suction port. For media with solid impurities or ferromagnetic impurities, filtration should be considered. For high-temperature media, cooling should be considered to ensure that the magnetic coupling does not exceed the working limit temperature.


When considering whether the speed is sufficient, first check whether the speed of the motor itself is normal, which can be measured with a tachometer. If the speed of the motor is normal, consider whether there will be slippage of the magnetic coupling.


(4) Insufficient lift.

The reasons for this failure are: there is air in the conveying medium, the impeller is damaged, the speed is not enough, the specific gravity of the conveying liquid is too large, and the flow rate is too large.


(5) Insufficient flow.

The main reasons for the lack of flow are: damage to the impeller, insufficient speed, high lift, and blockage of debris in the pipe.


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