Magnetic pump definition
Magnetic pump is a special pump, which belongs to a branch of the field of water pumps. It is a leakage free fluid conveying machine without dynamic seal. It is mainly designed for the centrifugal pump in the vane pump. Generally, it is composed of the pump body, isolation sleeve and connecting parts to form a shielding sealing chamber that can withstand pressure. There is a rotating permanent magnetic field outside the seal chamber, and through the effect of the magnetic field, the space non-contact drives the magnetic rotor parts inside the seal chamber to rotate synchronously, while the rotor parts inside the seal chamber drive the impeller to work on the fluid. Since there is no dynamic seal in the shielding sealing chamber composed of stator components, and the rotating shaft driving the impeller to work does not penetrate the shielding sealing chamber, zero leakage and pollution of the magnetic pump are ensured, and the problem of "running, emitting, dripping and leaking" is completely solved.
Magnetic pump working principle
N pairs of magnets (n is an even number) are regularly arranged and assembled on the inner and outer magnetic rotors of the magnetic actuator, so that the magnet parts form a complete coupling magnetic system. When the inner and outer magnetic poles are opposite each other, that is, the displacement angle between the two magnetic poles Φ＝ 0, at this time, the magnetic energy of the magnetic system is the lowest; When the magnetic poles rotate to the opposite of the same pole, that is, the displacement angle between the two magnetic poles Φ＝ 2 π/n, at this time, the magnetic energy of the magnetic system is maximum. After removing the external force, because the magnetic poles of the magnetic system repel each other, the magnetic force will make the magnet return to the state with the lowest magnetic energy. The magnet then moves and drives the magnetic rotor to rotate.
The Birth and Development of Magnetic Pump
Birth of magnetic pump
Leakage free pump first appeared in foreign countries. It was developed with the development of chemical industry, especially petrochemical industry and nuclear energy industry. At the beginning of this century, it began to manufacture various chemical products with crude oil, refinery distillate, refinery waste gas, natural gas and other raw materials, which is called petrochemical industry. Polymer chemical industry was born in the 1930s, which opened up a new way for chemical production by using large quantities of petroleum resources. During the Second World War, the production of synthetic rubber and explosives in some capitalist countries developed greatly. After the war, especially in the United States, the three major synthetic materials, rubber, plastic and fiber, developed rapidly. For the purpose of capital competition, some European countries and Japan also developed one after another in the mid 1950s. The rapid development of petrochemical industry has promoted the large-scale plant and the diversification and complexity of process flow. Therefore, the process pump for conveying medium is required to have higher reliability, safety and economy.
The reliability of the general process pump can be said to be the reliability of the shaft seal, while the weakest link of the general process pump (centrifugal pump) is the shaft seal. The inherent disadvantage of the shaft seal is that it must produce leakage to lubricate the seal face. There is always a leakage of 3~8cm3/h (the leakage allowed by the centrifugal pump standard) to maintain the pump operation. In a large and medium-sized chemical plant, there are thousands of pumps at most, and hundreds or dozens of pumps at least. Even if the seal fails to leak, the total amount of leakage to the atmosphere is considerable according to the standard allowable leakage. In addition, seal accidents actually occur frequently, because the shaft seal leakage is proportional to the service time of the pump. The shaft seal is gradually worn during high-speed operation, and its leakage increases with the increase of wear. The leakage of a large number of chemical substances not only pollutes the environment, but also endangers human health and production safety. Although the conventional structure of shaft seal has been improved and optimized in recent 20 years, no matter it is packing seal, mechanical seal (bellows seal), floating ring seal combined with mechanical seal and labyrinth seal, or even double end mechanical seal, it cannot completely eliminate leakage. It can be said that various shaft seals or conventional seals used for ordinary centrifugal pumps have reached the limit of development. Therefore, in some high standard situations where zero leakage is required, the only way is to cancel the shaft seal and develop an absolute leak free pump without shaft seal to replace it.
The magnetic drive pump is the preferred product to replace the original ordinary mechanical seal pump and other leak free pumps.
Aulank magnetic pump can be widely used in the transportation of flammable, explosive, toxic and harmful media in petroleum, chemical, pharmaceutical, printing and dyeing, environmental protection engineering, biological engineering and other fields. It is an ideal pump for creating "leak free factory" and "leak free workshop".
Development of Magnetic Pump
The history of leak free magnetic pump can be traced back to 1943, when Britain granted the patent to Charles Howard and Jeffrey Howard brothers. The early industrial development of magnetic pump was started by Howard Brothers through their company, Howard Machinery Development Co., Ltd. (hereinafter referred to as HMD). At the end of the 1940s, in 1947, the world's first magnetic pump was manufactured. Almost at the same time, Franz of West Germany from 1947 to 1948 Klaus also successfully developed the magnetic pump. Both of the above companies have 50 years of history in manufacturing magnetic pumps. There are also two companies that take the lead in using magnetic pumps in the world: one is Imperial Chemical Company of Britain; The second is Bayer Company in Germany. In the 60 years since the invention of magnetic pump, its development can be generally divided into two stages: the first 30 years and the last 30 years. In the first 30 years (that is, from the end of the 1940s to the middle of the 1970s), the magnetic pump, whether in the manufacturing field or in the application field, can be said to be a bleak 30 years, that is, there has been no large-scale production and no broad application market. Why?
The development history of magnetic pump In the first 30 years, there was little breakthrough in magnetic pump technology, mainly due to three reasons:
The first aspect: and the most important aspect is that the permanent magnetic materials required by the magnetic pump were only ferrite and aluminum nickel cobalt permanent magnets at that time, which could not meet the driving requirements of the magnetic pump due to their low magnetic energy product, weak magnetic induction strength, low intrinsic coercivity and other shortcomings.
The second aspect: The design and manufacturing technology of the magnetic pump has not been improved significantly due to various subjective and objective reasons and the limitations of various materials.
The third aspect: the cost and maintenance cost are particularly expensive.
Due to the imperfect design and manufacturing field and poor reliability, the application scope was greatly limited. In addition, some unsuccessful and unreliable products on the market had adverse effects, which led to the first 30 years of neglect.
The reason for the rapid development of magnetic pump in the past three decades depends on the following conditions:
The first aspect: the successful development of high-performance magnetic materials.
The second aspect: the successful development of high-performance bearing materials.
The third aspect: the continuous improvement of the magnetic pump structure.
The fourth aspect: the reliability, safety, economy and convenience of the magnetic pump have been verified by the application practice (users).
In our country, the magnetic pump appeared in the late 1970s and early 1980s. At the beginning of the research and development stage, the magnetic pump project was only limited to several large scientific research institutions.
In the late 1980s and early 1990s, small magnetic pump manufacturers appeared in Jiangsu and Zhejiang in the south, mainly producing small power plastic magnetic pumps.
According to relevant information, the application of magnetic pumps in foreign countries accounts for 30% of the total use of pumps, and less than 2% in China. The magnetic pump has the tendency to replace the ordinary pump and other leak free pumps within a certain range. Aulank has also been committed to developing innovative magnetic pumps.
Advantages and disadvantages of magnetic pump
Compared with the motor type DC brushless water pump, the magnetic pump has the following advantages:
1. The pump shaft is changed from a dynamic seal to a closed static seal, completely avoiding medium leakage. It can be used both on land and water, and is completely waterproof.
2. No need for independent lubrication and cooling water, reducing energy consumption.
3. It has low power consumption, high efficiency and damping effect, reducing the impact of motor vibration on the pump and the impact of pump cavitation vibration on the motor.
4. When overload occurs, the rotor will slip on the ceramic shaft, protecting the motor and pump.

At the same time, the magnetic pump also has the following disadvantages:
1. The efficiency of the magnetic centrifugal pump is lower than that of the ordinary centrifugal pump. It can not operate under 30% of the lower rated flow. Idling is more prohibited.
2. Magnetic centrifugal pump is generally used to transport the medium of unstable solid particles and magnetic particle materials are strictly prohibited from entering the pump because the wear resistance of the isolation sleeve material is generally poor.
3. Magnetic centrifugal pump of general structure is allowed to deliver liquid containing solid particles with diameter less than 0.15 mm and mass fraction not more than 5% (auxiliary system is required when exceeding).
4. The pump and motor are connected by a coupling. The coupling requires high accuracy for the installation of the centerline. Improper alignment will lead to damage to the bearing at the inlet and wear of the isolation sleeve against unilateral side leakage.
5. The magnetic drive of the magnetic centrifugal pump has two modes: synchronous drive and asynchronous drive. The internal and external magnetic rotors of synchronous drive are equipped with permanent magnets, so the temperature of the liquid transported must be lower than the maximum allowable temperature of the permanent magnet. A certain margin must be reserved. Although the cobalt and samarium permanent magnets can reach 350 ℃, the actual operating temperature generally does not exceed 260 ℃. Otherwise, high temperature may cause loss of excitation of the permanent magnets. For magnetic pumps with special structures, the maximum temperature can reach 450 ℃.
6. The magnetic centrifugal pump has high requirements on the material and manufacturing process of the isolation sleeve. If the material is not properly selected or the manufacturing quality is poor, the isolation sleeve cannot withstand the wear of the internal and external magnetic rotors and will be worn. Once it is broken, the conveyed medium will overflow, causing equipment failure and affecting the normal operation of the device.
7. When the temperature of the medium conveyed by the magnetic centrifugal pump exceeds the specified value, external cooling shall be provided. For example, an insulating chamber shall be set up, and the pump chamber shall be filled with coolant whose pressure is higher than the sealing pressure to cool the internal magnetic rotor and bearing. Alternatively, a spacer sleeve with interlayer can be used. Coolant shall be introduced into the interlayer, or the pump body shall be equipped with a cooling jacket and cooling coil. The single structure is complex and the cost is high.

Aulank MDW MDZ MDH series magnetic drive type high and low-temperature vortex pump, its flow parts are stainless steel, copper, cast-iron.  MDW pump adopts advanced hydraulic power, efficient magnetic transmission structure, novel appearance design, through precise processing and manufacturing technology, it come true energy-saving, safe and reliable, stable performance, long life, and other advantages, MDW pumps are widely used in middle high-end fields.
Application Area: High temperature mold temperature controlling, High and low temperature test instrument, Semiconductor precision temperature control.  Chemical equipment, Template temperature controlling, Ultrasonic cleaning equipment, High end printing and dyeing equipment, TCU.
Circulation Medium: Water, ethylene glycol, alcohol, thermal oil, hydrocarbon solution, silicone oil, refrigerant gasoline, dyestuff, chemical solution, liquid nitrogen, Electronic Fluoride Solution and other liquids without particles and fibers.