Magnetic coupling drive pump (referred to as magnetic drive pump) was first developed in 1947 by the British company HMD Geoffrey Howard. A few years later, Franz Klaus of West Germany also succeeded in developing one after another. The first companies to use magnetically driven pumps were Imperial Chemical Industries in the United Kingdom and Bayer Chemical in Germany. The primary purpose of developing a magnetically driven pump was to protect the safety and health of people working in industrial, chemical, nuclear, and defense industries. Since the mid-1970s, due to the development of a new generation of permanent magnet and silicon carbide bearing technologies, such as rare earth cobalt (1978) and the most powerful neodymium iron boron (1983), the technical level of magnetically driven pumps has been greatly improved . According to foreign samples and literature data, the flow rate of the magnetically driven pump can now reach 1150m3 / h; the lift reaches 500m; the medium temperature range is -120 ℃ ~ 450 ℃; the viscosity limit is 100-200cp; the abrasive solid content in the medium can reach 1.5 % (By weight), the solid particle size up to 100μm; take special measures, the pump can transport 20% insoluble solids in the slurry, the solid diameter of up to 20mm; system pressure up to 450bar. Magnetically driven pumps are also adapted to the high vacuum conditions that mechanical seals can not handle. These technical breakthroughs and other improvements make the magnetic drive pump reliability and economy have astonishingly improved. Investigation of the availability and ease-of-maintenance of magnetically-driven pumps and mechanical seal pumps showed that the rate of damage and failure of sealed pumps was significantly higher than that of magnetically driven pumps. For example, an average life of 6 months for a mechanical seal on a hydrothermal pump at 400 ° C, whereas a magnetically driven pump can operate for many years, the only maintenance required is for proper lubrication of the external bearings of the pump and the motor. The wealth of experience gained in the chemical industry has led to the conclusion that magnetically driven pumps have become the most economical solution to many process installations. Therefore, the use of magnetically driven pumps has increased not only because of a reliable environmental factor, but also significantly reduces the economic factors of operating and maintenance costs. Its range of applications has expanded from the delivery of hazardous liquids and valuable liquids to common pump applications where long life and low maintenance are required. For example, offshore vessels are driven by magnetic pumps to transport cold water for air conditioning systems due to high maintenance costs. The rapid growth in use of magnetically driven pumps in the last decade has become a common fixture in a variety of applications. Magnetically driven pumps now cover 90% of all applications in sealless pumps. Magnetically driven pumps use magnets to attract ferromagnetic materials and the magnetic or magnetic field between the magnetic properties of non-ferromagnetic material does not affect or seldom affect the size of the magnetic force, it can be non-contact through the non-magnetic conductor (isolated Sets) for power transmission, this drive known as the magnetic coupling. Motor through the coupling and the outer magnet together, the impeller and the inner magnet together. Between the outer magnet and the inner magnet with a fully sealed isolation sleeve, the inner and outer magnet completely separated so that the inner magnet in the medium, the motor shaft through the magnet pole between the suction force directly impeller synchronization Turn. Its main advantages: Because the drive shaft does not need to penetrate the pump housing, but the use of magnetic field through the air gap and the isolation sleeve thin-walled transmission torque, driven by the inner rotor, thus fundamentally eliminating the shaft seal leakage channel, to achieve a complete seal ; Overload protection when transmitting power; in addition to magnetic materials and magnetic circuit design have higher requirements, the remaining part of the technical requirements are not high; magnetic drive pump maintenance and repair workload is small. Its main drawback: magnetic drive pump efficiency lower than ordinary centrifugal pump; anti-single-sided leakage isolation cover materials and manufacturing requirements; magnetic drive pump due to material and magnetic transmission restrictions, so the domestic general only for transportation 100 ℃ the following, 1.6MPa below the media; As the isolation sleeve material wear resistance is generally poor, so the magnetic drive pump is generally used for conveying medium without solid particles; Coupling requirements of high, right in the wrong, Can lead to damage to the bearings at the inlet and to the wear of the one-sided leak isolation sleeve.