As one of the modern engineering ceramics, SiC ceramics is a new synthetic inorganic non-metallic material. Hardness is second only to diamond, with excellent chemical resistance, wear resistance, high temperature resistance and 1/4 of stainless steel "target=_blank> stainless steel. When the temperature of the medium is high, it is matched with stainless steel" target=_blank> Stainless steel parts produce gaps or interference and cause bearing damage; the fracture toughness is 1/50 of stainless steel "target=_blank> stainless steel, the material is brittle, and it is easy to break when subjected to impact force, especially at the corners.
The modulus of elasticity is 1/50 of stainless steel "target=_blank> stainless steel, which is mechanically brittle and easily broken. The coefficient of thermal expansion is 1/4 of stainless steel "target=_blank> stainless steel, when it is combined with (stainless steel "target=_blank> stainless steel) It should be noted.
Structural problems
If the pump with a liquid temperature of 100 (°C) uses a rotor shaft of diameter d=50 (mm) (stainless steel "target=_blank> stainless steel), the following problem will occur: the gap between the bushing and the rotor shaft will reach 0.052 mm, That is, the gap between the sleeve and the rotor shaft is reduced by 0.052 mm at room temperature (20 ° C). To obtain the gap at normal temperature, the gap between the sleeve and the rotor shaft becomes larger. Therefore, the sleeve is easily broken at normal temperature operation, and reused. It is more prone to failure when it is hot.
Dalian Sifang Electric Pump Co., Ltd. has solved the stress concentration caused by the end of the bearing sleeve through continuous improvement and improvement, improved the reliability, and added an elastic automatic compensation sleeve, which can automatically compensate the difference of the material expansion due to the temperature rise due to the temperature rise. The silicon carbide bearing has been successfully applied on the shielded electric pump, and the pump can operate normally in the temperature range of 0 °C - 250 °C. Silicon carbide bearings are used in our company's basic PB, reverse cycle PBN, water cooled high temperature PBG, mud type PBLK, self-priming PBZ, thermal insulation PBB, high power vertical PBGL, small flow PBX and other shielded electric pump products. The actual application has been fully realized. The power used is 0.75-75Kw, and the temperature range is 0°C-250°C. The main application conditions are: a. long life is required, b. medium has strong chemical corrosion, c. low density, easy to vaporize medium, d. The temperature is high, e. There are traces of small soft particles in the medium, f. The medium does not allow the powder to be worn by the friction pair, such as the pure water industry, or the conditions with high purity requirements.
Characteristics of SiC bearings developed by Dalian Sifang Electric Pump Co., Ltd.:
1. The bearing adopts pressureless sintered crystal SiC, grade: SSiC, purity: ≥99.5%.
2. The unique structure can automatically compensate for the difference in material expansion caused by the temperature rise in the radial direction, so that the pump can operate normally in the temperature range of 0 °C - 250 °C.
3. The service life is more than 10 times that of ordinary graphite bearings. Http://news.chinawj.com.cn Editor: (Hardware Business Network Information Center) http://news.chinawj.com.cn
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