Magnetic pump phylogeny
In 1940, Charles and Geoffrey Hwward first solved dangerous medium chemical pump leakage problems and solving method is to use magnetic drive pumps. During 30 years later permanent magnetic driving technology progress is slow due to the materials. In 1983, high-performance nd-fe-b magnetic material comes out, supplying the key component material for rapid development of magnetic drive pums. In recent years, permanent magnet drive technology has already extended to other mechanical sealing from pump, focus on the technique to improve the reliability of the equipment and new anti-corrosion medium materials research, fluid technology and manufacturing assembly precision. Magnetic pump represents state manufacturing technology level, in recent years the industrialized countries in efficiency, magnetic pump life, manufacturing cycle, cost and reliability have made breakthrough progress.
Magnetic transmission technology transports the oringinal power through its shaft external magnet components to working shaft internal magnet, internal and external magnetic components are isolated by isolating cover, thus the working shaft does not need to extend closed space, cancel the dynamic sealing, realize no sealing, zero leakage. Magnetic transmission technology is mainly used in chemical industry, petroleum chemical industry, medicine and food industry pumps and compressors, mixer and valve, etc. At present fluid machinery extensive used traditional mechanical seal has been replaced by permanent magnet driving in foreign departments.
2 applicable area broaden, technical performance improved
2.1 magnetic driving is the most effective and safety method in sealing field
Permanent magnetic transmission ie. permanent magnetic coupling is the most safety method to machine that need sealing, to harmful, toxic, pollution, dangerous, pure and valuable products and production process, with a wide range of applications. Petroleum chemical industry, medicine, movies, electroplating, nuclear power industries of liquid mostly have corrosive, inflammable, explosive, toxic, precious, leakage will bring liquid waste and environmental pollution, Vacuum, semiconductor industry needs to prevent external gas intruding, food, medicine need to ensure the purity of medium. Magnetic transmission technology in these areas to find useful. British Howard machinery development Co., LTD. (HMD) devotes itself to manufacture no sealing pump from 1946, from then on, in 37 countries it has sold 70,000 sets and its annual sales of 28 million pounds. An American pharmaceutical factory has hundreds of centrifugal pump with mechanical seal, processing various acids, these pump dry runs due to design problems, can only use 2 ~ 3 months, with a change to ansimag company produced k1516 series magnetic-driving pumps, which is still running from 1993 to 1998 (4.8 hours daily operation 365 days a year). The Midwest, container board factory was disliked the synthesis of rotary vane pump seal of the engineer, said the pump is "the sky of darks" ansimag installed without the company seal magnetic pump liner etfe, 11 months without stop running. America one big plant faces serious difficulties of methanol conveying. Because of methanol flammable, 60 degrees approximate to boil, the flow is only 7m3/h, high differential pressure is 250m. To resolve the problem by dickow magnetic-driving pumps, its flow is 15m3/h, differential pressure is 400m, ensure the methanol zero leakage, ensure the safety of operators and factory, and solve the methanol containing bubbles transportation problem..
2.2 In the technical performance, magnetic pump develops to mini, large-scale
To satisfy the market need, petrochemical company equipment to the large-scale development, China must have a thousand tons of oil refineries, 100 tons of ethylene plant. Mechanical equipment needs to meet heavy load, low energy consumption, long period, and meet the environmental requirements. In China, in cloning foreign products, we find that magnetic pump manufacture technique and requirements of the material is very high. Even small power of 11 ~ 13kw pump, the reliability of manufacturing cost can't be accepted by users. Strong resistance to corrosion, high pressure and high temperature of high-power pump is still blank. Currently the development of magnetic pump limit should be described by HMD company: flow from 1m3 / h to 681m3 / h, differential pressure from 10m to 500m, temperature range from -100℃ to 450℃, the system pressure from the vacuum to 400bar primemover power is 350kw. Miniature pump is specially developed for some departments, such as laser cooling and analytical instruments, chemical agents supplement, biological engineering, cooling cycle and printer nozzle etc. The gear pump and motor integrated connection. Suitable for 24v, 36v DC power, speed artificial automatic control. The minimum flow is 10ml/min, differential pressure is 7bar. Japan iwaki company for the electroplating, cooling cycle with the md micro magnetic transmission gear pump series flow range is 7.5 ~ 288l/min, transmission power is 1/25 ~ 1/3 horsepower.
2.3 Various types of pumps can transform for magnetic-driving pumps
Centrifugal pump is the leading product of magnetic pump, magnetic drive rotating displacement has 25 years of history, only in the near 7-8 years there is a broad base on design and manufacture level and torque capabilities. Emphasis is magnetic transmission gear pump and screw pump, the maximum transmission capacity reaches 400mm, rotate speed is 3500r/min, power is 150kw. Located in the border with the United States and districts of gas turbine compressor lubrication utility plants of aberrant pump is the meshing gear pump. Oil pump due to high-pressure difference and average every two months is excessive wear and scrap, causing compressor closed. In 1992, using magnetic transmission three screw pump, has continuous operation and no maintenance. British tuthill successful application of its magnetic transmission gear pump for Scottish company pumped water system in the process of chemical additive, this pump replaced the screw pump, conform to the hygiene safety regulations.
2.4 magnetic driving compressor
The magnetic transmission inner bearing is located in the sealed space, which using the sealed medium for lubrication and cooling. View our material level, magnetic transmission in gas transmission machinery is still unused. Canada nova magnetic Co., LTD produced overpressure fan, under 170 bar helium pressure, leakage rate is 1cm3 / h, bearing life is more than 10000h. Another series of booster fan, free flow is 750m3/h, when in the flow of 400m3/h, system differential pressure is 35mpa and realize the zero leakage. In addition, the special properties of magnetic drive are also applied to leak-off mixer, valve, etc. The application in the refrigerator haven't got the related information, we are doing the exploring works of realizing the magnetic transmission to used in refrigerant compressor, because the coolant, especially the freon leaked can cause serious environmental problems
3 new technology, new process, new structure
Magnetic transmission technology is not only simple use of magnets functions, it is the transmission technology, material technology, manufacturing technology integration. The world first-class professional factories, their products enjoy reputation in the world, so we can't cloning. Now these "veteran" still on efficiency and quality improvement, reduce cost, extend the average time between twice maintenance.
3.1 new technology, new process
The magnetic material selection basic understanding by each country, ndfeb material working temperature below 150℃, smco working temperature below 250℃, for micro pump can choose ba-ferrite. Pump body materials are divided into metal and non-metal two kinds. Metal stainless steel doesn't mean not rust to all liquids, it is mainly used in the process of its compatible liquids and precious liquids, ultra pure liquid. Nonmetal is specially developed for the corrosive application. It is divided into two categories. One is the pure plastic pump, use pure polypropylene or ethylene fluoride hot plastic molds. Such as Britain vanton CGM pump flow 136m3/h, head: 84m(temperature: 135℃), motor power: 32kw. Secondly, it is currently popular lining pump of corrosion pump liner a method of plastic. General pump body available malleable iron manufacturing and fep, pp, the pfa, PVDF, etfe seamless lining. Magnetix new mta series no sealing pumps and other lined pumps key advantages are using its advanced pfa fluoropolymer lining, with its unique pfa corrosion resistance to chemicals widely ability than etfe, PVDF or other non-metal materials. To use the patent technology: casting process, the film thickness and uniformity, the pfa lined with rotating molded in competition. Applied to high purity and high temperature liquid is more ideal. Iso pump ptfe liner minimum thickness is 3mm, tenon chamfer the pump shell, pump shell with high-borosilicate glass manufacturing. Isolation cover is the key components, it seals the rupture can lead to catastrophic fluid leakage. Single metal sealing cover a wide range of applications, although vortex will generate heat energy loss, if it adopts high strength, high resistance materials can limit to the minimum loss, such as: the Hamiltonian alloy 2.4610-4 (c). Taiani invented by the metal laminated isolation cover made five countries in many patent, has been used in the design, its efficiency can reach 99% and transmitting power reach 150 horsepower. Zirconia ceramics zro2 (single) isolation cover, anti-corrosion of acid solution, has high hardness and good performance, and the sliding high mechanical strength and elasticity (e = 2 x 105n/mm2) already used to working pressure 250bar. But the ceramic wall thickness is big, cannot plastic processing. Early 1999 American patent imo pump, new isolation cover with carbon fiber with epoxy resin manufacturing, thickness less than 2.8 mm, connecting with stainless steel flange. Suitable for operating pressure is 31bar, temperature 232 degrees Celsius, transmission torque 407N.M, under 3600r/min rotate speed, power can reach 149kw. Double isolation cover provides double insurance and available for inspection space. Japan iwaki mde series pump double cover by glass fiber reinforced plastic manufacturing. Ansimag two-coating epoxy resin isolation cover magnetic -driving pumps for conveying alumina mill 2 years without any replacement parts. Isolation cover welding is weak and corrosion sensitive source, advanced manufacturing method is plastic molding, such as deep pulling, spinning, outspread spinning. Axial and slide bearing are manufactured by high abrasion resistance sic. Dry running according to the practice is no sealing magnetic pump. Elaborate fluid balance design, back sealing ring and impeller hole connecting action, balance liquid axial thrust reduces pressure of impeller. Entrance adjustment valves prevent low flow of igv, turbulence, ensure low flow operation. Two sintering sic bearing optimization design of supporting points, sleeve spiral groove helps washing and lubricating shaft diameter, providing dry running 30min guarantee, can make the operators have time to adjust system and normal operation, to avoid catastrophic failure. The Germany company itt Richter produced mnka series pump pure sic bearing, under 2900 r/min can dry running 1h.
3.2 new technology
Using optimum physical size to ensure the economic effectively use magnets volume, static magnetic withdraws torque and temperature dependency through finite element calculation and extensive testing. Axial and radial bearing are lubricated by pumping medium. The lubricated flow passage must provide necessary flow. The new automatic adjustment bearing can withstand big radial and axial thrust. With outstanding corrosion resistance capability sic or carbon graphite slide bearing, it shrinks in metallic enclosure, guarantee the stability of the mechanical operation, even if the shoulder is damaged, remains reliability and maintainability of the bearings. Another technique is fluid balance, bearing strength is limited to the minimum. Currently inner bearing life can achieve 10000h. High temperature problem: KSB hot oil pump uses annular cooler, surrounded by coupling to keep the temperature in the near magnet materials under the maximum allowed temperature, although medium average temperature is 350 degrees. HMD type vortex coupling has unique "torque circle" design, expand temperature range to 450℃ without cooling. The patent technology -- fan automatic cooling: in all kinds of speed range magnetic couplings can automatic cooling, need not external cooling system, only using ring gas rotor automatically finished. Completely reliability: on the magnetic-coupling there is friction ring to protect the magnets, to prevent dry running, flow sensor can be installed in the pipeline, ensuring cut off or low flow, Foreign digital power control monitors unit random equipment determines the overload condition, temperature sensors, leakage sensor, using PLC (programmable controller) magnetic transmission of real-time monitoring of work. Continuous monitoring of the bearing clearance, monitoring any ball shaft pump wear, make shaft replaced in time before damage.
3.3 new structure
Almost all of the magnetic drive pumps adopt "back pull" structure. The whole coupling parts, bearings components separately as a unit, without disassemblying pump shell from pipeline and bottom seat, beneficial for maintenance. For example, Japanese Fuji film chemical company before use double mechanical seal, because the chemical centrifugal pump shaft seal, corrosion wear at least once. The seal of the replacement is very expensive, often accounts for 25% of the total pump, replacing time spend 5 hours. Use global magnetic drive pumps, two years running after completely successful. Compared with double mechanical seal, maintenance cycle doubled, with reduced to 15min. In 1997, all pump are replaced by magnetic pump, and change of the pump life expectancy (without any service) for five years. allweiler proposed no impeller shaft design, impeller is installed in the middle of sic bearing, standard clearance is applied for patents. Fan should use separated type electrical motor, insert sleeve bearing, both repairing motor and fan bearing can be finished within 30min. A wide range of components exchange with en22858 / iso2858, ansib73.1, api610, din, bs standards. Balance according to api/iso implementation.
4 The advanced manufacturing technology and management
In order to adapt to the global competition and cooperation, the world pump industry is developing its own technical advantage, expand the scope of products to meet the market diversity demand. Products fit for the functional requirements at the same time, no doubt should fully meet strict safety, reliability and ecological environment protection requirement. The advanced manufacturing technology is advanced topics. Three years ago, magnetic drive pumps pioneer---HMD introduced long-term production mode and research programs, and finally completely redesigned it assembly equipment. Investment 100 million pounds to expand the HMD product capability, and spend 70 million for the new high-speed processing system, buy six sets of machining center. However it is not only with the advanced machine to increase output, important is to establish the flexible processing, reduce cycle time. Before transmitting torque laps around the factory to manufacture chains in 540m, spend 8-9 weeks and today, is a family organization, many machines are even in the company of cad/CAM system, the engineer of standard according to user's rapid reform, make creative directly on the processing center. The same circle torque operation, only need 30 online spending 2 days. Due to the rapid manufacturing, material pump can quick delivery, in some cases, within 3 days. According to their words "competitive advantage, we will make the next century, create more business opportunities. Advanced product from the advanced design and strict test, 3d design and simulation, without drawing processing, virtual manufacturing, rapid prototyping in. High strength alloy material, metallurgical test pump body, impeller and isolation of strong corrosive action by ensuring long life: the wear of sic pumps in chemical process lubrication cooling system in the industry, including the extensive testing system of high pressure 345bar self-priming and hot, cover design. Each parts, components and systems are careful examination and evaluation. With the demand that the HMD made strategic principle is: advanced materials, development of key supplier relationships, through the organization of manufacturing cycle, reduce manufacturing cycle, reduce queuing, accelerate the process. The author inquire on the net for 20 several famous magnetic transmission company in the world, and found that they were subsidiaries and sales. Quality design and manufacturing technology exquisite pump by world, can decide for issuers to respond quickly market strategy. Services include answer user application problems encountered, pump selection, special pump designed, 24 hours a day for users technical consultation. The 21st century will continue to manufacture technology not only manufactured under the condition of proper running machines and equipment, and will create extreme environment of mechanical equipment operation. The 21st century should be in conformity with the products manufactured and eco friendly green products, magnetic transmission technology is adapt to this trend, let us learn from foreign advanced experience in promoting the development of this technology!
