Differences between magnetic and shielded pumps

　　Magnetic pumps and shielded pumps in a number of aspects there are significant differences, these differences are mainly reflected in their working principle, structural characteristics, performance and maintenance difficulties and so on. The following is a detailed analysis of the differences between the two:

　　First, the working principle

　　Magnetic pump: magnetic pump through the magnetic coupling to achieve contactless transmission of power. Its motor and pump shaft are separate, the outer magnet on the motor shaft and the pump shaft of the inner magnet through magnetic interaction, driving the pump shaft and impeller rotation. This approach avoids direct contact between the medium and the motor, thus realizing leak-free operation. However, due to the magnetic transfer process will be part of the energy into the magnet heating, so the efficiency of the magnetic pump will be somewhat affected.

　　Shielded pumps: shielded pumps are directly utilized by the motor principle, its pump shaft and motor shaft share a common shaft, impeller and motor rotor are made on the common shaft and rotate together. Motor stator winding in the shielding set of peripheral, motor and pump into one, through the motor principle directly drive the impeller rotation. This way makes the shielded pump has high efficiency, because the energy transfer is more direct and efficient.

　　Second, structural characteristics

　　Magnetic pump: the structure of magnetic pump is relatively complex, the motor and pump shaft are separated and connected by magnetic coupling. The thickness of its isolation sleeve is usually more than three times that of the shielded pump, which makes the magnetic pump more advantageous in terms of sealing and reliability. However, magnetic pumps need to be connected to the motor via a coupling and require centering operations.

　　Shielded pumps: Shielded pumps are much more compact, with the motor and pump integrated into one unit, eliminating the need for couplings and centering operations. This structure makes shielded pumps more compact in size, saving space. However, because the motor bearings are in direct contact with the medium, and the motor does not have a fan, its heat dissipation and lubrication are dependent on the internal circulation of the medium, which may lead to a higher failure rate of the motor.

　　Third, the use of performance

　　Magnetic pumps: magnetic pumps have better applicability to strong corrosive media, because its isolation sleeve is thicker, can effectively protect the motor and bearings from media erosion. However, the magnetic pump is sensitive to magnetic materials, the medium contains metal particles (such as iron filings) can not be used, because the ferromagnetic material will be attracted by the magnet steel leading to failure. In addition, due to the energy loss in the magnetic transfer process, the maximum power that magnetic pumps can achieve is lower than shielded pumps, so they may be limited in high flow and high pressure applications.

　　Shielded pumps: Shielded pumps, on the other hand, are more suitable for media containing metal particles, as their motors are not in direct contact with the media and are not affected by magnetic materials. At the same time, because the shielded pump directly utilizes the motor principle, its efficiency is theoretically higher than the magnetic pump. However, the shielded pump may not be as good as the magnetic pump in terms of sealing and reliability, and its maintenance is also more difficult.

　　Fourth, maintenance difficulty

　　Magnetic pumps: magnetic pump maintenance is relatively simple, its repair process is similar to ordinary pumps. However, due to the complex structure of the magnetic pump and sensitive to magnetic materials, so in the maintenance process requires special attention to avoid damage and contamination of magnetic materials.

　　Shielded pumps: shielded pumps are relatively difficult to maintain. Because of its compact structure and the motor and the media in direct contact, once the failure is often difficult to repair themselves. In addition, the shielded pump motor bearing lubrication and heat dissipation are dependent on the internal circulation of the medium, which also increases the complexity of its maintenance.

　　In summary, magnetic pumps and shielded pumps in the working principle, structural characteristics, performance and maintenance difficulties, there are significant differences. In the choice of which pump to use according to the specific conditions and needs for comprehensive consideration.