Influence of type of high-coercivity permanent magnet on characteristics of end magnetic clutch

Abstract

In this work, a study has been made of the influence of various types of high-coercivity permanent magnets on the key parameters (misalignment angle of half-clutches, power loss in current-conducting screen, screen temperature exceeding ambient temperature, liquid flow rate required to cool the screen with water, and forces of attraction between half-clutches) of a sealed equipment having an end magnetic clutch with retention of its basic parameter, namely, the value of the transferring torsional moment (torque). The overall dimensions of the magnetic clutch and half-clutches where various types of magnets are used remain unchanged.In [1], a study was made of the influence of type of high-coercivity permanent magnet on the characteristics of a cylindrical magnetic clutch (MC). End MCs having high-coercivity permanent magnets (barium oxide magnets or magnets from alloys of rare-earth elements samarium-cobalt (Sm-Co) and neodymium-iron-boron (Nd-Fe-B)) are used also in sealed (leak-proof) equipments operating in atomic, chemical, and other branches of the industry. Sealed equipments and end MCs are manufactured at specialized enterprises. In the manufacturing process, it is often necessary to use in the same MC different types of magnets while keeping the basic parameter, viz., the value of the transferring torsional moment of the MC, unchanged. Let us examine on an example the influence of various types of magnets on the key parameters of a sealed equipment having a magnetic clutch: misalignment (mismatch) angle of half-clutches, power loss in current-conducting screen, screen temperature above ambient temperature, liquid flow rate required to cool the screen with water, and forces of attraction between half-clutches.As an example, let us consider a sealed labyrinth screw pump of the trademark LG-1/20 (head 20 m and volume delivery 1 m 3 /h) [2] made by Sverdlovskii Research and Design Institute of Chemical Machine Building (SverdNIIkhimmash) for radiochemical plants.The general view of the pump is shown in Fig. 1. On the axis 1 of the casing 2 is mounted on the sliding bearings 15 the driven (slave) end magnetic half-clutch 4 assembled with the screw bushing 11. The axis 1 is secured between the flange 14 and the screen 9 by the bolt 5. The sleeve nut 12 is immovably fixed in the casing 2 and fastened to the flange 14 by dowels (pins). The electric motor 6, with the driving end magnetic half-clutch 8 fastened to its shaft, is mounted on the support 7.The support 7, the casing 2, and the flange 14 are braced together by the dowels 10. The material of the sealing gaskets is fluoroplastic-4 (Teflon). The casing 2 of the pump has a suction (intake) pipe 13 and a delivery pipe 3.

Dynamic Characteristics of Magnetic Coupling in Horizontal Axis Wave Energy Device

“…During the sea trials, the problems such as seal failure and excessive starting torque of the mechanical drive device were found. In order to solve these problems, the magnetic coupling is applied, which is an isolated transmission and usually used in the situation wherestrictsealing property is required to achieve complete sealing [13][14][15][16][17].…”