Characteristics and Application of Welded Metal Bellows Mechanical Seal

Welded metal bellows mechanical seal is a new type of mechanical seal developed rapidly in recent 30 years. Because of its special structure and material selection, its application scope is more and more extensive. With the development of the national economy, especially the development of the production capacity and technical level of China's petrochemical industry, the requirements for the shaft seal are becoming more and more strict and the use parameters are becoming higher and higher. In the case of temperature from - 200% to - 40%C, or above 200 centigrade and some medium with high temperature and high pressure, and under the condition of varying duty, the welding metal bellows mechanical seal is generally better solved, whether it is the pump, the reaction kettle, the high speed centrifugal compressor seal. The welded metal bellows developed by ourselves have also achieved good results. In 1998, China successively issued and implemented the mechanical seal standard JB/T 8723-998 for welding metal corrugated pipe for pump and JB/T 3 124-998 for welding metal corrugated pipe kettle.

Characteristics of mechanical seal of metal bellows

(1) Good floating. One of the most remarkable features of metal bellows type mechanical seal is its good floatability. Therefore, the vibration, deflection and rotation axis of the shaft are not sensitive to the deflection of the shell hole. For example, the machine seal with a large swing, the sealing with severe vibration and the deviation caused by improper installation, the corrugated pipe machine seal has a good adaptability and a satisfactory sealing effect.

(2) The secondary moving sealing ring is cancelled. Therefore, the high temperature resistance, corrosion resistance and gas escape and loss of elasticity of rubber are excluded. It is also possible to avoid the relaxation tendency of the tetrafluoroethylene ring, the U type seal and the malady that the sealing material will lose its sealing effect at high temperature or low temperature because it is not easy to maintain its original shape under the load.

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