Vacuum bellows

    Vacuum bellows is a very common type of vacuum fittings in vacuum piping systems. The bellows used in the ultra-high vacuum system must have reliable sealing performance and service life, and be able to achieve bending, expansion and eccentric bending.

    Bellows are usually divided into two types: formed bellows and welded bellows. The material of bellows used in ultra-high vacuum systems is generally SUS316 stainless steel.

    When making a formed corrugated pipe with a slightly larger diameter, the stainless steel sheet is first rolled into a cylindrical shape, and the joints are welded. Insert the cylinder into the bellows mold, and complete the forming of the bellows by hydraulic pressure.

    In the ultra-high vacuum system, the bellows connecting the molecular pump and the mechanical pump are mostly shaped bellows with NW flanges at both ends. The advantages of forming bellows are simple manufacture and low cost. The disadvantage is insufficient expansion and flexibility. Welded bellows can make up for the shortcomings of forming bellows.

    Welded bellows are thin-walled corrugated hoses formed by welding circular stainless steel sheets with alternating inner and outer diameters. The welding method is plasma welding. This bellows has great flexibility and is an indispensable part of the connection of the ultra-high vacuum system and various motion introducers. Reasonably choose the natural length of the bellows, and the service life can reach hundreds of thousands of times.

(huiputech)