Application of New Technology of Permanent Magnet Transmission in Foreign Countries on Magnetic Pump

Abstract: The latest developments of permanent magnet drive technology in foreign countries are summarized. Application areas broaden, improve technical performance; there are some new technologies, new processes, new structure; application of advanced manufacturing technology and management, the magnetic pump more efficient, reliable and durable.

Keywords: permanent magnet drive technology material structure application

1 Introduction:

British 1940 Charles and Geoffrey Hwward for the first time to solve the problem of leakage of hazardous medium chemical pump, the solution is to use magnetic drive pump. In the following 30 years permanent magnet drive technology due to the reasons for the progress of magnetic materials is very slow. The advent of high performance NdFeB permanent magnet materials in 1983 provided the key components for the rapid development of magnetically driven pumps. In recent years, permanent magnet drive technology has been extended from the pump to other mechanical seal, technically focused on improving the reliability of the equipment, anti-media corrosion of new materials research, fluid technology and manufacturing assembly accuracy. Magnetic pumps represent the level of manufacturing technology in a country. In recent years, magnetic pumps in industrialized countries have made breakthrough progress in efficiency, life expectancy, manufacturing cycle, cost and reliability.

Permanent magnet drive technology is the motive force of the prime mover through the shaft of the outer magnetic components to the inner shaft of the magnetic components, the inner and outer magnetic components separated by the isolation cover, so the working axis need not extend the space to be closed, the cancellation of the move Sealed to achieve no seal, zero leakage. Permanent magnet drive technology is mainly used in chemical industry, petrochemical, pharmaceutical, food industry pumps and compressors, mixers and valves. At present, the large number of traditional mechanical seals used in fluid machinery in foreign countries have gradually been replaced by permanent magnet drives.

2 applications broaden, improve technical performance

2.1 Magnetic drive is the seal of the most effective and safe solution

Permanent magnet drive that is permanent magnet coupling For machinery that needs to be sealed, it is the safest solution to harmful, toxic, polluting, dangerous, pure and expensive products and the production process. It has a wide range of applications. Most liquids in the petrochemical, pharmaceutical, film, electroplating, nuclear power and other industries are corrosive, flammable, explosive, poisonous, expensive and spillage will lead to the waste of working fluid and environmental pollution; vacuum, the semiconductor industry to prevent the outside world Gas intrusion: diet, medicine to ensure the purity of the media. Permanent magnet drive technology has found its way in these areas. British Machinery Development Company Limited (HMD) since 1946 committed to the manufacture of sealless pumps, so far in 37 countries around the world have sold nearly 70,000 units, annual sales of 28 million pounds. A pharmaceutical factory in the United States has hundreds of centrifugal pumps with mechanical seals to handle all kinds of acids. These pumps often run dry due to design problems and can only be destroyed within 2 to 3 months and replaced with Ansimag K1516 series of magnetic transmission pump, put into operation since 1993 (4.8 hours a day for 365 days a year) until 1998 is still running. Synthetic caustic soda is a big problem for rotary vane pump seals in the Midwest container mills where engineers describe the pumps as "maintaining the darkness of the night" with Ansimag's ETFE-lined, sealless magnetic pump running 11 Month without downtime. A large-scale chemical plant in the United States is facing serious difficulties in transporting methanol. Because of methanol flammable, close to boiling 60 ℃, the flow rate of only 7m3 / h, the pressure difference up to 250m. The problem is solved by Dickow magnetic drive multi-stage end suction pump, its flow is 15m3 / h, pressure 400m, to ensure zero leakage of methanol to ensure operator and factory safety and to solve the methanol containing bubbles transport problem.

2.2 magnetic pump in the technical performance to the micro, large-scale development

To meet the needs of domestic and foreign markets, petrochemical companies complete sets of equipment to large-scale development, China must have a number of annual output of 10 million-ton refinery, million-ton ethylene plant. Mechanical equipment to meet the heavy load, long cycle, low energy consumption, and in line with environmental requirements. My country found in imitation of foreign products, manufacturing magnetic pump material and process requirements are high. Even 11 ~ 13kW medium and small power pumps, the reliability of manufacturing costs can not be accepted by users. For strong corrosion resistance, high pressure, high temperature power pump is still blank. At present, the development limit of the magnetic pump should be described by HMD's products: flow rate from 1m3 / h to 681m3 / h, pressure drop from 10m to 500m, temperature range from -100 ℃ to 450 ℃, system pressure from vacuum to 400bar, Motive power up to 350kW. Micro pumps are specifically developed for research and development in certain sectors such as laser cooling, analytical instrumentation, chemical replenishment, bioengineering, cooling cycles, and printer nozzles. Gear pump and motor closed integration, suitable for 24V, 36V DC power supply, speed manual automatic control. The minimum flow rate is 10ml / min and the pressure difference is 7bar. Japan Iwaki company for electroplating, cooling cycle MD series of miniature magnetic transmission gear pump flow range is 7.5 ~ 288L / min, transmission power 1/25 ~ 1/3 horsepower.

2.3 Various types of pumps can be transformed into magnetic drive pump

Centrifugal pump is the leading product of magnetic pump, magnetic drive rotary displacement pump although 25 years of history, only in the past seven or eight years in the design and manufacturing level and large torque capacity has a wide range of foundation. The focus is magnetic gear pump and screw pump, the maximum transmission capacity of 400Nm, speed 3500r / min power of 150kW. Located in the United States border Juyou Gas Power Plant, the turbine compressor lubrication pump is a regular-track external gear pump. Oil pump due to high pressure on average every two months over wear and scrapped, causing the compressor to shut down. After the switch to magnetic three screw pump in 1992, has been continuous operation, without any maintenance. Tuthill, UK, has successfully applied its magnetic drive gear pump to pump water into the Scottish process water system, which replaces the screw pump and meets health and safety regulations.

2.4 magnetic transmission compressor

The magnetically driven inner bearing is located in the sealed space, which is lubricated and cooled with a sealed medium. In view of the level of material manufacture in China, magnetic transmission has not been applied in gas conveying machinery. Canada Nova Magnetic Co., Ltd. produced overpressure fan, 170bar helium pressure, the leakage rate of 1cm3 / h, bearing life of more than 10000h. Another series of pressurized fan, the free discharge of flow 750m3 / h, 400m3 / h flow system pressure 35MPa, to achieve zero leakage. In addition, the special characteristics of magnetic drive also applies to leak-free blenders, valves and other equipment. The application of the freezer has not been related to information, the author is to achieve the magnetic drive applied to the refrigeration compressor is being explored, due to the leakage of refrigerants, especially Freons can cause serious environmental problems.

3 new technology, new technology, new structure

Magnetic drive technology is not just a simple use of the same magnet repulsion, heterosexual phase suction, it is the transmission technology, materials technology, manufacturing technology integration. The reason why we have a world-class professional manufacturer whose products enjoy a reputation in the world that we can not imitate. Now these "veterans" are still doing efficiency and quality improvements, reducing costs and extending the average time between repairs.

3.1 new materials, new technology

The selection of magnetic materials Basic recognition of the common understanding of all countries, NdFeB material operating temperature below 150 ℃, SmCo material operating temperature below 250 ℃, the micro-pump barium ferrite can be used. Pump material sub-metal, non-metallic two categories. Metal stainless steel does not mean that all liquids are stainless, it is mainly used for its compatible process liquid, precious liquid, ultra-pure liquid. Nonmetal is developed specifically for corrosive applications. It is divided into two kinds of situations. One is pure plastic pump, with pure polypropylene or vinyl fluoride thermoplastic mold. Such as the British Vanton CGM pump flow of 136m3 / h, head 84m (temperature 135 ℃), the motor power 32kW. The second is the lining pump, which is a popular method of plastic corrosion-resistant pump lining. General pump body made of malleable iron, FEP, PP, PFA, PVDF, ETFE seamless lining. The key advantage of Magnetix's new MTA series of hermetically sealed pumps and other liner pumps is the use of its advanced PFA fluoropolymer liner, which is more resistant to chemicals than ETFE, PVDF or other non-metallic materials due to its unique, Famous Patented technology: Casting film technology, coupled with thick and uniform PFA lining, and rotary die casting competition. Used in high purity and high temperature fluid is more ideal. ISO pump PTFE liner minimum thickness of 3mm, with mortise and tenon pressure pump casing, pump casing made of borosilicate glass. The shield is a key component of the seal and its rupture can lead to a catastrophic hazard to fluid leakage. Single-layer metal enclosures are used in a wide range of applications. Although eddy currents generate heat and energy losses, the use of high-strength, high-resistance materials minimizes the loss, such as Hastelloy C-4 (2.4610). The patented 5-ply metal shield made by Taiani has been used in many designs with 99% efficiency and 150 horsepower. Monolithic ceramic ZrO2 barrier, resistant to caustic solution, acid corrosion, high hardness and good sliding properties, as well as high mechanical strength and elasticity (E = 2 × 105N / mm2) have been used for working pressure 250bar. However, larger ceramic wall thickness, plastic processing can not be. IMO pump, patented by the United States in early 1999, is made of carbon fiber and epoxy with a thickness of less than 2.8 mm and is attached to a stainless steel flange. Suitable for operating pressure 31bar, temperature 232 ℃, transmission torque 407Nm, power 3600r / min up to 149kW. Double shield provides double insurance and space for inspection. Japan IWAKI MDE series double-skin pump made of glass fiber reinforced plastic. AnSimag Double Epoxy Isolator Magnetic Drive Pump delivers alumina to the paper mill, running for 2 years without changing any parts. Isolation welding is the weak point of the structure and the sensitive source of corrosion. The advanced manufacturing method is plastic forming, such as deep drawing, spinning and extending spinning. Shafts and plain bearings are made of high wear resistance SiC. Dry-running is the unscrupulous magnetic pump unsightly sign. Careful fluid balance design, the rear seal and the impeller hole joint action to balance the liquid axial thrust to reduce the impeller pressure. The inlet trim valve prevents pre-rotation at low flow rates, reduces turbulence, and ensures low flow operation. The two sintered SiC bearings are optimized for design support points. The helical grooves in the bushing help flush and lubricate the shaft diameter, providing a guaranteed 30-minute dry run, giving the operator time to adjust the system, resume normal operation and avoid catastrophic damage. Germany ITT Richter's MNKA series of pure SiC bearings pump, can be dry operation at 2900r / min 1h.

3.2 new technology

The optimum physical size to ensure cost-effective use of the magnet volume, magnetostatic torque and temperature dependence of the finite element calculation and a wide range of experiments. Axial and radial bearings are lubricated by the pumped medium. Lubrication flow path to provide the necessary flow. The new self-adjusting bearings can withstand large axial thrust and radial forces. A sliding bearing made of SiC or carbon graphite with superior resistance to corrosion and abrasion, which is shrink-fitted in a metal housing to ensure the stability of the machine operation, maintains the reliability and maintainability of the bearing even if the shoulder breaks. Another technique is to balance the fluid so that the bearing is limited to a minimum. The current bearing life of up to 10000h. High temperature issues: The KSB hot oil pump uses a circular cooler to surround the coupling chamber, keeping the temperature near the magnet below the maximum allowable material temperature, although the average medium temperature is 350 ° C. The HMD vortex-type coupling has a unique "torque ring" design, expanding the temperature range to 450 ° C without cooling. Patented technology - Automatic fan cooling: The magnetic coupling is automatically cooled over a wide range of speeds without the need for an external cooling system and is done automatically with the toroidal rotor only. Complete reliability: the magnetic coupling is equipped with a muzzle ring to protect the magnet; to prevent dry operation, the flow sensor can be installed in the user pipeline to determine the flow or low flow; foreign units randomly equipped with digital power control monitor Determine the overload conditions, leakage sensors, temperature sensors, the use of PLC (programmable logic controller) real-time monitoring of magnetic transmission work. Continuous monitoring of the outer bearing running clearance, monitoring any ball pump wear, the shaft pump in time before damage replacement.

3.3 new structure

Almost all of the magnetic drive pump are used "back out" structure. The entire coupling parts, bearing parts, respectively, as a unit, do not have to demolish the pipeline, from the bottom to take out the pump casing, benefit maintenance services. For example, Japan's Fujifilm Film Chemical Company previously used dual mechanical seal centrifugal pumps, due to chemical corrosion wear, shaft seal at least once. This seal replacement is expensive and typically accounts for 25% of the pump's total value, which can take up to 5 hours to change. After using Global Magnetic Drive Pump, it has been completely successful for 2 years. Compared with the double mechanical seal, inspection cycle increased by 1 times, the installation and disassembly reduced to 15min. All pumps were replaced by magnetic pumps during 1997 and the pump's life expectancy (without any service) was set at 5 years. ALLweiler reason-free design of the impeller shaft, impeller mounted in the middle of SiC bearings, the standard clearance is applying for a patent. Separate fan motor applications, plug-in sleeve bearings, whether it is maintenance or fan fan bearings can be completed within 30min. Parts of a wide range of EN22858 / ISO2858, ANSIB73.1, API610, DIN, BS and other standard pump interchangeable. Balanced according to API / ISO implementation.

4 advanced manufacturing technology and management

In order to meet the competition and cooperation in the world, the world's pump industry is developing its own technological advantages and expanding its product range to meet the diverse and individual needs of the world's largest markets. Products meet the functional requirements at the same time, no doubt should fully meet the stringent safety, reliability and environmental requirements. Advanced manufacturing technology is the theme of advanced products. Three years ago HMD, a pioneer of magnetic transmission pumps, introduced long-term production methods and a complete research program and finally redesigned its assembly equipment. Invest £ 1 million to expand HMD's product capabilities, spend $ 700,000 on new high-speed machining systems and purchase 6 machining centers. However, not only advanced machines are used to increase production, it is important to establish flexible processing to reduce cycle time. In the past, torques had to be transmitted around the factory by 540 m and in the manufacturing chain for 8 to 9 weeks. Today, manufacturing is a family-style organization. Many machines are connected to the company's CAD / CAM system. Engineers rapidly make standard parts according to users' needs A creative reform, upload directly to the machining center. Running the same torque ring 30m, online only takes 2 days. Due to the rapid manufacture, the material pump can be delivered very quickly, in some cases a few days. In their words, "Competitive advantages will allow us to embark on the next century and create more business opportunities." Advanced products from advanced design and rigorous testing, 3D design and simulation, non-paper processing, virtual manufacturing, rapid prototyping are under way. Metallurgical testing of high-strength alloy materials, pumps, impellers and isolation sleeves ensure long life: Lubricated cooling systems for non-abrasive SiC shaft pumps undergo extensive testing in the chemical process industry, including high system pressures 345bar, self-priming and thermowell design. Each part, component and system are thoroughly inspected and rated. HMD believes that the principles of manufacturing and demand are: advanced strategic raw materials; the development of key supply relationships; manufacturing cycle through the organization to reduce the manufacturing cycle; reduce queuing and speed up the process. The author inquired about 20 well-known magnetic transmission companies online and found that they have subsidiaries and sales networks all over the world. Quality design and manufacturing are determined by skilled pump distributors around the world to react strategically and strategically to the market. Services include answering user application problems, pump selection, special pump design, technical advice for users 24 hours a day. 21st century manufacturing technology will not only continue to make machines and equipment that operate under normal conditions, but will also create machines that operate in extreme conditions. Products manufactured in the 21st century should be eco-friendly, friendly and green products, magnetic drive technology is to adapt to this development trend, let us learn from advanced foreign experience to promote the development of this technology now!

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