Magnetic pump structural characteristics and use and maintenance

Asia Pump Network News】 【magnetic pump (magnetic drive pump) mainly by the pump head, magnetic actuator (magnetic cylinder), motor, connecting the backplane and other parts of several components. Magnetic pump Magnetic drive by the outer rotor, the inner rotor and the non-magnetic isolation sleeve composition When the motor drives the outer rotor rotation, the magnetic field can penetrate the air gap and non-magnetic material, driven by the impeller with the inner rotor for Synchronous rotation, synchronous power transmission to achieve non-contact, easy to leak of the dynamic seal structure into zero leakage static seal structure. As the pump shaft, the inner rotor is completely closed by the pump body and isolation sleeve, thus completely solving the problems of running, running, dripping and leakage. Structural characteristics of the magnetic pump and the use of maintenance 1, the structure of the magnetic pump Magnetic pump by the pump, magnetic coupling and drive motor is composed of three parts. The left end of the shaft is equipped with impeller, the right end is equipped with an inner rotor, the shaft supported by the sliding bearing. The brackets connect the pump to the motor and ensure the position accuracy of the inner and outer magnetostric rotors. When the motor drives the outer magnetic rotor to rotate, the magnetic field drives the inner magnetic rotor to rotate synchronously by the air gap and the separation sleeve, so as to drive the impeller to rotate. 1.1 Pump Pump generally use corrosion-resistant, high-strength engineering plastics, corundum ceramics, stainless steel, etc. as a production material, has good corrosion resistance, and can be transported medium from pollution. Such as CQB series of magnetic drive pump contact is transported liquid part is made of chemical resistant fluorine plastic alloy. Fluoroplastics alloys consist of a mixture of ultra-high molecular weight, poly-FEPs thermoplastically-processed with one or more other plastics, which can be added to fillers. Such as by the ultra-high molecular weight poly FEP and PTFE plastic alloy, the former accounted for the weight ratio of 0.1% to 99.9%, which accounted for the weight ratio of 99.9% to 0.1%, with a dry powder co-grinding or wet Method of co-grinding method of manufacturing. Using hot or cold pressure sintering and other methods into a variety of products, to overcome the cold PTFE flow and deformation defects, can extend the service life. Magnetic pump bearings are immersed in the transport medium, and transport medium lubrication and cooling. More commonly used bearings in China are mostly graphite and reinforced plastic. Graphite, especially impregnated graphite, has good self-lubrication, heat-resistant corrosion, low friction coefficient and wide range of applications. However, graphite is more brittle and has lower strength and is sensitive to shaft bending and local overload. Special attention should be paid to graphite. Steel as the matrix, the porous bronze as the middle layer, the plastic surface layer of the three-layer composite bearing high compressive strength, low friction coefficient, dimensional stability, noise reduction shock absorber, has been applied in recent years. 1.2, magnetic coupling Magnetic coupling is to achieve non-contact torque transmission so as to achieve a complete leak-free key components. There are generally disc-shaped and cylindrical two forms. Since the disc-shaped coupling consists of two ring-shaped magnets facing each other and a spacer therein, an axial force exists between the two ring-shaped magnets, and in particular, when the power is large, the axial force is large and it is very difficult to overcome it. Generally less used. The cylindrical coupling comprises an outer magnet rotor, an inner magnet rotor and a spacer (separate) sleeve. The outer magnet rotor is connected with the motor and is in the atmosphere. The inner magnet rotor is integrated with the pump shaft. The whole rotor is Contained in the pump housing and spacer and immersed in the transport medium, the spacer between the inner and outer rotor and fixed to the pump housing, the pump housing and the isolation sleeve to form a communication within the completely sealed chamber. Magnetic steel in the outer cylindrical surface of the outer rotor and the inner cylindrical surface of the rotor closely arranged in the circumferential direction, forming a "combination of push-pull magnetic circuit." At present, there are many magnetic materials available for the magnetic pump, commonly used are SmCo5 (abbreviated as 1: 5), Sm (Co, Cu, Fe, Zr) 7.4 (referred to as AlNiCo, ferrite and rare- 2:17), Nd-Fe-B and the like. The rare earth permanent magnet material is the most preferred, the most powerful is the hinge iron boron Nd-Fe-B, the maximum energy product as high as 28 × 104T · A / m or more, the inspected coercivity of over 1120kA / m, highly favored . However, its working temperature can not exceed 120 ℃ under the condition of high temperature. The energy product of Sm (Co, Cu, Fe, Zr) 7.4 is about 192 × 103T · A / m and its operating temperature can reach as high as 300 ℃ Cylindrical couplings should pay great attention to the position between the inner and outer magnetic rotors in the process of design, machining and assembly, otherwise radial force will be generated. This radial force not only affects torque transmission, but also has a direct bearing on the life of the bearing, serious, will make the magnetic coupling can not work. The key to solve this radial force is to ensure that the magnetic rotors inside and outside should have the necessary coaxiality. In addition, the magnetic pump assembly and disassembly, there should be dedicated tooling and tools to protect personnel and parts from knocking bruises. In the magnetic pump work, the spacer in an alternating magnetic field, will induce eddy currents. This eddy current, on the one hand, consumes shaft power and reduces transmission efficiency. On the other hand, it is transformed into heat, to the medium and to the temperature of the circulating medium. Therefore, the design of the spacer must pay attention to the material selection and geometry size, especially for conveying easily vaporized liquid. After the parameters and requirements of the pump are given, the main factor for the loss of power p of the spacer can be approximated as Pαd2 / p · σ, where d is the spacer diameter and p is the resistivity of the material. Allowable stress for the material. Visible, the main way to reduce eddy current loss is to use high resistivity, high strength materials, and minimize the spacer diameter. There are two general categories of materials that are commonly used to make glands: metallic and non-metallic materials. Metal materials have high mechanical strength, wall thickness can be controlled at the thinnest, in order to reduce the gap between the inner and outer magnetic rotor, increasing transmission efficiency, while reducing the eddy current loss generated within the spacer. China generally use 1Cr18Ni9Ti and alloy. Non-metallic materials have good corrosion resistance, eddy current loss will not produce, can improve the transmission efficiency, but often by the pressure of the media and temperature constraints and limits the scope of application, the domestic commonly used is PTFE. 1.3, Motor Magnet pump commonly used motor is commonly used motor, special requirements according to the provisions of matching. 2, the use and maintenance of the magnetic pump 2.1, the use of precautions (1) After the installation is complete, turn the coupling by hand to check for friction phenomenon. (2) In order to prevent debris from entering the pump, a filter is arranged at the inlet of the pump, and the filtering area is larger than 3 to 4 times of the cross-sectional area of ​​the pipe. (3) is strictly prohibited air transport. (4) Lift the pump should be installed in the outlet pipe check valve to prevent water hammer suddenly shut down damage. (5) open the pump program: open the inlet valve before driving, the pump filled with liquid to be transported; close the outlet valve; jog the electric motor, check the steering pump is correct; pump start, the outlet valve should be slowly open, Pump to be up to the normal operation, then the outlet valve transferred to the desired opening. Trial run 5 ~ 10min, if no exception, can be put into operation. Shutdown procedure: Close the outlet valve; cut off the power supply; shut down the inlet, clean the flow passage in the pump and cut off the power when not in use for a long time. (Editor: LLX QQ:) Recommended reading: 2017 Exhibition Information 2016 Yiwu Fair

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