Modified structure of magnetic driving pumping

Abstract

The invention provides an improved structure of a shaft seal-free magnetic-drive pump, aims at improving rigidity of a fixed shaft, and particularly improving a metal magnetic-drive pump provided with a corrosion resisting lining to obtain a high-rigidity fixed shaft system. The improved structure of the shaft seal-free magnetic-drive pump is particularly improved aiming at below 200 DEG C high temperature and high corrosion resistance usages to improve rigidity of a rotor system arranged in the structure and meet high performance requirements. The improved structure of the shaft seal-free magnetic-drive pump comprises a high-rigidity metal supporting seat, a rear shaft hole seat, an impeller and a fixed shaft, wherein the high-rigidity metal supporting seat is an extending member arranged on the axial inner side of the inner diameter of a pump inlet, is covered by corrosion resistance fluoroplastics, and provides main supporting strength for the fixed shaft, the rear shaft hole seat is arranged at the bottom of a sealing rear cover and used for providing auxiliary support for the fixed shaft; the impeller is provided with a special flow channel design to lower inlet flow speed to provide low NPSHr and high-performance pumping outlet; and fixed shaft can be a single ceramic shaft or a high-rigidity compose fixed shaft, and the high-rigidity compose fixed shaft is composed of a ceramic shaft sleeve, a metal shaft and a sealing nut and used for supporting running of an inner rotor.

Description

[0001] This patent is a divisional application of application number 201110344803.5 technical field [0002] The present invention relates to an improved structure of a magnetic drive pump, especially an improvement to the fixed shaft structure of a cast iron magnetic drive pump with a corrosion-resistant lining, in order to enable the pump to operate at a temperature of 200°C It can have high reliability operation ability and meet the high-performance requirements required for pump transportation. The invention improves the fixed shaft support structure of the cast iron pump casing and the related flow channel structure to increase the support rigidity of the fixed shaft to reduce fluorine Plastic structural parts are unfavorable factors affected by temperature, and improve the performance, reliability and service life of the pump. Background technique [0003] Press, the general sealless magnetic drive pump has been widely used in many corrosion-resistant or leak-proof pur...

AI Technical Summary

Problems solved by technology

[0005] In 2006, the US patent US7033146Sealed magnetic drive sealless pump, this citation is to explain the bearing design of the magnetic drive pump dry running, but the illustration clearly shows the bilateral support and fixed shaft structure of the traditional plastic magnetic drive pump. The tripod is located in the inner diameter space of the pump inlet. Axially extending through the impeller hub hole, the shaft fixing seat is located at the end of the tripod and inside the impeller hub hole to support one end of the fixed shaft. The tripod in this case has minimized the flow resistance to the inlet channel, and the rear The cover is a cup-shaped shell structure. There is a shaft hole seat at the bottom without any through hole, which is used to support the other end of the fixed shaft. The strength of the plastic tripod and the back cover is easily affected by temperature. To reduce the influence of the tripod on the inlet channel, deliberately extend the length of the tripod so that the shaft seat passes through the hole of the impeller hub, but this will greatly reduce the radial support force of the tripod, which is only suitable for low temperature and low power applications;

[0009] In 2002, the Chinese patent CN2482597Y Magnetic drive corrosion resistant fluorine plastic liner pump, the cited case is a magnetic drive pump with a plastic lining and a metal shell, the purpose is to explain the structure and corrosion resistance of the fluoroplastic lining, and the fluoroplastic lining is integrally formed The shaft support frame, the fluoroplastic back cover is a cup-shaped shell structure, the bottom has a shaft hole seat without any through holes, and is used to support the other end of the fixed shaft, but it also points out in the text that the fixed shaft supported by both sides is composed of The support structure made of fluoroplastics can deform elastically, and can buffer the vibration of the shaft load when the pump is running, but this cited case does not further explain whether the structural strength and reliability for high-temperature applications at 200°C are applicable

[0015] In 2001, the US patent US7101158B2Hydraulic balancing magnetically driven centrifugal pump, this citation is to explain the axial thrust balance of the magnetic drive pump, but it clearly shows that its fixed shaft is an equal-diameter structure, and its supporting tripod is installed at the pump inlet When the inner diameter is large, the outer diameter of the shaft fixing seat supporting the tripod is too large, which will affect the impeller inlet flow channel and reduce the pump performance. In the structure of the inlet flow channel, its inner diameter must be increased to reduce the flow resistance of the impeller inlet

[0017] 2007 U.S. Patent US7249939B2 Rear casing arrangement for magnetic drive pump, this cited case is applicable to the magnetic drive pump with bilateral support for the fixed shaft and the rotating shaft. The gap between the rotor and the inner rotor is narrow, and the high corrosion-resistant plastic material is a thermoplastic material whose strength decreases with temperature. The conventional technology will add a second layer of reinforcement structure outside the corrosion-resistant material of the back cover. This cited case is In the middle or outside of the two-layer structure of the side cylindrical surface, a non-metallic strip-shaped circular reinforcement is added to increase the strength of the cylindrical part on the side of the back cover. This method is better than the conventional method of using straight fibers in the circumferential direction The multi-layer winding method is better, but this method cannot effectively overcome the bending deformation of the cylindrical part when the shaft hole seat at the bottom of the back cover bears radial force, and this cited case also indirectly proves that the supporting force of the fixed shaft will also be affected by the circular shape of the back cover. Influence of barrel strength

[0019] In 2001, the US patent US6293772B1containment member for a magnetic-drive centrifugal pump was applied to a metal magnetic-drive pump with a corrosion-resistant lining. This cited case clearly pointed out that the strength of the plastic tripod and the back cover of the magnetic-drive pump is a problem that needs further attention. The support tripod often affects the impeller inlet channel and reduces the pump performance. The strength of the back cover is to resist the liquid pressure and provide fixed shaft support. The solution in this case is the first and second layers at the bottom of the back cover. A disc-shaped metal reinforcement is embedded in the middle of the structure, so that the radial force on the cantilever fixed bearing will be evenly transmitted to the cylindrical part of the rear cover, and the shape of the reinforcement does not include a small diameter and an axially inner extension. It is used to strengthen the support and grip of the fixed shaft, so that it is strong enough to support the fixed shaft in a cantilever manner, so that the support tripod can be avoided and the fixed shaft has sufficient support strength, but it does not clearly explain the cylindrical part of the back cover side The strength, whether it can avoid the problem of skewing of the fixed shaft after being strengthened

[0023] 3. The flow resistance of the pump inlet channel

[0024] 4. The cavitation resistance of the impeller inlet channel (NPSHr)

[0025] 5. The strength of the back cover, including the cylindrical part and the bottom

[0026] However, the respective solutions and solutions of these citations cannot simultaneously meet the needs of high-rigidity fixed shafts for high-temperature 200°C liquid transportation. The structural improvement of the magnetic drive pump of the present invention can overcome the above problems at the same time

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