FlangeMetal bellowsIt is widely used in various piping systems to compensate for axial, lateral and angular displacements caused by temperature and pressure fluctuations. The core component of the flanged metal bellows is the bellows, which can be axially, laterally and angularly displaced by the deformation and pressure resistance of the bellows, and withstand the fluid pressure of the system. Other parts are structural parts, which play the role of guiding, supporting, connecting and shunting. According to the design and use requirements, the metal bellows and related structural parts are welded into different types of bellows expansion joints in the axial, transverse and angular directions according to the required structure.

The characteristic of the corrugated expansion joint is that it can produce corresponding displacement under the action of pressure, axial force, lateral force or bending moment. It has the characteristics of pressure resistance, vacuum sealing, corrosion resistance, temperature stability and long service life. Therefore, it has been widely used in many industrial fields. Mainly used in the following aspects.

1. Elastic sensitive element for instrument

As a kind of elastic sensitive element, flange metal bellows has high requirements for its elastic performance. The bellows serving as an elastic sensing element essentially converts pressure into a displacement output or pressure into a concentrated force output. The bellows that turns the pressure into a concentrated force output has almost no deformation, so the stress on the bellows is less than the stress on the bellows that outputs the displacement, and the effects of elastic aftereffect and hysteresis can be said to be zero. Thus, the reliability and accuracy of an instrument using a force balancing bellows as an elastic sensitive element can be very high. This is why multi-force balance bellows are used as elastic sensitive elements in measuring instruments. The bellows that converts pressure to displacement output will generate a larger pressure on the bellows. Attention should be paid to the design. At the same time, the elastic aftereffect and hysteresis have a certain influence on the elasticity of the bellows.

For the bellows used as an elastic sensitive element in the instrument, the stiffness of the bellows should be as small as possible in the design. It can use the bellows internal (or external) volume changes in the displacement process for temperature control and temperature measurement.

2. Vacuum switch vacuum seal

Vacuum switch is a kind of switch equipment that makes and breaks current in vacuum. Its main contact is located in the vacuum interrupter,Metal bellowsIt is a key component in the vacuum interrupter. Only after the metal bellows is used, the moving contact can be moved from the outside of the vacuum interrupter by mechanical force, and the housing of the vacuum interrupter can be kept completely sealed. Every time the vacuum switch is opened or closed, the dust cover will undergo a large displacement. Large and frequent axial displacement is easy to cause bellows fatigue damage. The bellows is an important part of the vacuum interrupter shell. If the vacuum interrupter is damaged, the service life of the vacuum interrupter will be terminated due to air leakage.

The fatigue life of flanged metal bellows is related to its structure, material and service conditions. The working stroke of bellows for vacuum switch has a great influence on its fatigue life. For the same kind of bellows and vacuum switch, in order to obtain a longer fatigue life, can only reduce the working stroke of the bellows or contact opening distance. On the contrary, ifMetal bellowsThe working stroke or contact opening distance increases, and the fatigue life of the bellows will be greatly shortened. Therefore, the main performance of the vacuum switch bellows is axial displacement and vacuum tightness. The vacuum switch has two working states, on or off. After opening, the bellows needs to be stretched and deformed. When it is closed, the bellows will be compressed and deformed. In order to ensure the service life of the vacuum switch, the tension and compression displacement of the bellows must be reasonably designed.