Fault analysis of magnetic coupling


Fault analysis of magnetic coupling

Analysis and Solution of Common Faults of Magnetic Coupling Pump

Reference - Analysis of magnetic pump faults and solutions to common faults of magnetic pump

What if the magnetic pump encounters problems? Here is the solution.

(1) The magnetic pump shaft is broken. The pump shaft of the magnetic pump is made of 99% aluminum oxide porcelain. The main reason for the pump shaft breaking is that the shaft is twisted due to the dry grinding of the bearing due to the empty operation of the pump. When the pump is disassembled for inspection, it can be seen that the bearing has been seriously worn. The main way to prevent the pump from breaking is to avoid idling.

(2) The bearing of the magnetic centrifugal pump is damaged. The bearing of the magnetic pump is made of high-density carbon. In case of water failure or impurities in the pump, the bearing will be damaged. If the coaxiality between the inner and outer magnetic rotors of the cylindrical coupling is not guaranteed, the life of the bearing will also be directly affected.

(3) Magnetic centrifugal pump can not pump out liquid. The failure of magnetic pump to pump liquid is easy to occur, and there are many reasons. First, check whether there is air leakage in the suction pipe of the pump, whether the air in the suction pipe is discharged, whether the liquid filled in the magnetic pump is sufficient, whether there is debris blocking in the suction pipe, and whether the pump reverses (especially after the replacement of the motor or the maintenance of the power supply line), and whether the pump suction height is too high. If the problem cannot be solved through the above inspection, the pump can be disassembled for inspection to see whether the pump shaft is broken, whether the dynamic ring and static ring of the pump are intact, and whether the whole rotor can move axially in a small amount. If it is difficult to move axially, check whether the carbon bearing is too close to the pump shaft. It is worth noting that the magnetic pump has been repaired for several times and no problem is found. It should be noted whether the magnetic coupling works normally. The bearing, inner magnetic rotor and spacer sleeve will generate heat during operation, which will increase the working temperature, on the one hand, it will reduce the transmitted power, on the other hand, it will cause great trouble to the magnetic pump that transports liquid that is easy to vaporize. The power transmitted by the magnetic steel is a continuous decreasing curve with the increase of temperature. Generally, the decrease of its transmission capacity is reversible below the Ji limit temperature of the magnetic steel, but irreversible above the Ji limit temperature, that is, after the magnetic steel is cooled, the lost transmission capacity can no longer be restored. 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, making the magnetic centrifugal pump coupling invalid. Therefore, the magnetic centrifugal pump should be designed with a reliable cooling system. For the medium that is not easy to vaporize, the cooling circulation system generally leads out the liquid flow from the impeller outlet or pump outlet, and returns to the suction population through the bearing and magnetic drive part. For the medium that is easy to vaporize, the heat exchanger shall be added or the liquid flow shall be led to the storage tank outside the pump to avoid the heat returning to the suction population. For the medium with solid impurities or ferromagnetic impurities, filtration shall be considered, and for the high temperature medium, cooling shall be considered, To ensure that the magnetic coupling does not exceed the operating temperature limit. When considering whether the speed is enough, first check whether the speed of the motor is normal, and use a tachometer to measure. If the speed of the motor is normal, consider whether the magnetic coupling will slip.

(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 proportion of the conveying liquid is too large, and the flow is too large.

Insufficient flow. The main causes of insufficient flow are: impeller damage, insufficient speed, high lift, and blockage of debris in the pipe.

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