Airtightness refers to the non-leakage performance of components under certain internal and external pressure difference. Bellows class components work, the cavity filled with gas or liquid medium, and there is a certain pressure, so must ensure the tightness. The sealing test methods include pneumatic sealing test, leakage test, liquid pressure test, and leak detection with soapy water or helium mass spectrometer.

Elastic components in industrial use, their working environment often have a certain degree of vibration, some components used as vibration isolation parts, itself in the vibration condition. For the elastic element used under special conditions, the natural vibration frequency (especially the fundamental frequency) of the element must be prevented from being close to the vibration frequency of any vibration source in the system, so as to avoid the damage caused by resonance. Bellows are widely used in various fields. In order to avoid the damage of the resonance surface of bellows, the natural frequency of bellows should be lower than the vibration frequency of the system, or at least 50% higher than the vibration frequency of the system.

Metal bellows are used in a wide range of temperatures and are usually given prior to the design and manufacture of elastic components. Some special purpose bellows, through liquid oxygen (-196℃) or lower temperature liquid nitrogen, pressure resistance up to 25MPa. Large corrugated expansion joints (nominal diameter sometimes larger than lm) used for pipe network connections are required to bear pressure of 4MPa, withstand temperature of 400℃, and have certain corrosion stability. The temperature adaptability of elastic element depends on the temperature resistance of elastic material. Therefore, according to the use of elastic components of the temperature range, choose the appropriate temperature parameters of the elastic material, in order to manufacture qualified bellows components.

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