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How to Solve the Phenomenon of Magnetic Force Failure of Magnetic Drive Pump

Cause Analysis

The medium conveyed by the Magnetic drive pump is volatile and easy to vaporize when the temperature rises. Moreover, the inner magnetic rotor and the isolating sleeve in the isolating sleeve will generate heat during operation, which will increase the working temperature. If the temperature of the medium entering the pump is higher than the vaporization temperature corresponding to the inlet pressure, the medium will be vaporized. , The formation of air bubbles will cause great safety hazards to magnetic pumps that transport easily vaporized liquids. The static pressure energy obtained by the medium is too low, which leads to a decrease in the vaporization temperature and severe cavitation to cut off the flow of the medium. Dry friction causes the bearing to burn out and the shaft is held. The pressure inside the impeller is different when the pump is running. The magnetic pump has the lowest pressure at the inlet due to centrifugal force, but when the pressure is lower than the saturated vapor pressure in the working state, the medium will cavitation. When the cavitation develops to a certain degree, a large number of bubbles are generated, which block the flow channel, which destroys the continuity of the liquid flow in the pump, and finally causes the pump to evacuate and cut off the flow and dry friction occurs. The vortex loss of the isolation sleeve heats up due to the cooling failure. , Will cause the medium temperature and the temperature of the inner magnetic rotor to rise sharply, which will damage the magnetic force.

Feasible solution

1. Change the shaft of the Magnetic drive pump from semi-hollow to full-hollow and change the return hole drilling to through hole to increase the cooling and lubricating flow of the medium.

2. When installing, make the spiral grooves of a pair of sliding bearings match the direction of rotation, so that the cooling medium flows more smoothly, the heat generated by the high-speed rotation of the outer magnetic rotor and the induced eddy current can be taken away in time, improving the sliding bearing, pump shaft and thrust ring Cooling and lubricating effect.

3. Cut the impeller. Cutting the impeller under the condition that the efficiency is basically unchanged, on the one hand, it can increase the vaporization temperature of the medium by reducing the velocity energy of the liquid and increasing the static pressure energy; on the other hand, it can also reduce the input of external energy to prevent the temperature of the medium from increasing. And vaporization. At the same time, the operating range of the magnetic pump is expanded and the influence of process fluctuations on the pump is reduced.

Magnetic drive pump