The difference between magnetic pump and shielded pump
1. The shielding pump directly uses the principle of the motor, and the energy consumption of the magnetic pump motor is transferred to the impeller through the internal and external magnetic steel (part of the energy is converted into the heating of the magnetic steel), so the efficiency of the shielded pump is higher than that of the magnetic pump in theory.
2. As can be seen from the structure, the biggest disadvantage of the shielded pump is that it is impossible to maintain (very difficult). In the process of use, whether there is a problem with the pump body or the motor, the user is basically unable to maintain it by himself. The repair of the magnetic pump is not much different from the ordinary pump. The motor bearing of the shielded pump is in contact with the medium, so it is difficult to guarantee its service life. Therefore, the shielded pump is not only difficult to maintain, but also difficult to repair, and its reliability can not be guaranteed (such as bearing faults can not be predicted, you can not detect and observe fault phenomena and precursors), shielded pumps can not find hidden dangers in operation, once there is a problem, it is fatal damage.
3. The thickness of the isolation sleeve of the magnetic pump is more than 3 times that of the shielded pump, so the tightness and reliability are more guaranteed.
4. The motor bearing of the shield pump is lubricated by the medium, the motor does not have a fan, and the heat dissipation of the motor is carried out by the internal circulation of the medium. This leads to a higher failure rate of the shielded motor. Magnetic pump motor is an ordinary motor, which dissipates heat by fan and is mature and reliable. But also because the noise of the magnetic pump is louder than that of the shielded pump.
5. The structure of the shielded pump is more compact, so it is smaller than the magnetic pump and saves space.
6. The shielded pump has no coupling, and the magnetic pump and the motor are connected through the coupling and need to be aligned.
7. Due to the problem of magnetic material, the maximum power of magnetic pump is lower than that of shielded pump, which leads to the limitation of magnetic pump in some heavy load applications caused by high flow rate and high pressure.
8. The magnetic pump is more applicable to the strong corrosive medium than the shielded pump, because its isolation sleeve is thicker (the thickening of the shielding sleeve of the shielding pump will affect the electromagnetic effect of the stator winding and the rotor winding).
9. The magnetic pump can not be used when the medium contains metal particles (such as iron filings), because the ferromagnetic material will be attracted by the magnetic steel, resulting in failure. And the shielded pump can be handled.