Views: 0 Author: Site Editor Publish Time: 2022-05-15 Origin: Site
A magnetic drive pump is a new type of sealless pump which uses the principle of permanent magnet transmission technology to realize the contactless transmission of torque. There is no mechanical connection between the driving shaft and the driven shaft, and there is no need for a dynamic seal in the structure. Therefore, this type of pump has no seal and can realize zero leakage. It is especially suitable for conveying flammable, explosive, volatile, toxic, corrosive, and precious liquids. Magnetic pumps are mostly used in occasions where the pump is required to only leak slightly or even no leakage, as well as high vacuum occasions where the mechanical seal is difficult to be competent. In recent years, the pump has been widely used in petroleum, chemical industry, electroplating, pharmaceutical, food, paper selection, printing and dyeing, and other industries abroad.
Al2O3, Si3N4, and SiC ceramics have been successfully used in China for the production of magnetic drive pump shafts.
Ceramics belong to inorganic non-metallic materials, and ceramics in a broad sense is usually defined as an inorganic non-metallic material made by high-temperature sintering. High-temperature structural ceramics are mainly bonded by ionic and donor bonds and the bonding force is the relatively strong electrostatic gravitational force between positive and negative ions or shared electron pairs, so it has a high melting point and hardness. Ceramics is a polycrystalline multiphase system structure, consisting of a large number of microfine grains. There are a certain amount of pores, microcracks, and precipitates between the grains.
The domestic trial ceramic shafts are made of refined ultra-fine powdered raw materials and cold-pressed into shape by reasonable formulation. The formulation contains adhesives, degassing agents, toughening agents, etc., and is sintered at high temperatures.
The mechanical properties of ceramics are usually not significantly deformed or destroyed under the action of external forces, and its elastic modulus is high, tensile and flexural strength is much lower than compressive strength, and impact strength is low.
In foreign countries, ceramic parts are generally produced by the hot isostatic pressing method, which is uniform pressurization of the sample in each direction with gas (argon or nitrogen) in a high-pressure vessel. In this equipment, the gas pressure can reach 300 MPa and the heating temperature can reach 2000°C. Hot isostatic pressing can be sintered complex-shaped products so that the product obtains a very high density and excellent physical and mechanical properties, but expensive, now, China's technology in this area is relatively weak.
At the same time, the use of ceramic pump shafts in the domestic is still a trial or trial stage, at present, mainly from three aspects to improve the working conditions of the ceramic shaft to make up for the manufacturing process deficiencies.
First of all, in the pump shaft design using simple geometry, shaft fixed design for flexible connection, conventional metal shafts are rigid support, while the ceramic shaft is the most afraid of impact load, in order to prevent the shaft brittle fracture, the shaft end is fixed on the fluorine plastic or other soft material pieces, in the process of operation so that the support parts have elastic deformation, the shaft has a certain buffer effect on the load.
Second, try to reduce the load on the ceramic shaft. In the design as far as possible to reduce the impeller, internal magnetic rotor, and other parts of the mass, reduce the load on the shaft.
Third, shorten the length of the shaft. Reasonable structural design, as far as possible to shorten the length of the shaft.
Taicang Magnetic Centrifugal Pump Co., Ltd. was born in 1979. It cooperated with Shanghai Chemical Design Institute to form a unique core research project with magnetic drive pump, and achieved great success. It has become the first company in China to comprehensively design and produce magnetic drive pump. Today, Taicang magnetic centrifugal pump Co., Ltd. has become a leading manufacturer of magnetic drive pumps in China, with many patents and 12 utility model patents.
