The bellows described in this paper can be used in ultra-high vacuum systems for bending, telescoping and eccentric action (Fig. 1), which requires reliable sealing performance and service life of bellows.
Fig.1 Use forms of formed bellows
Bellows are usually divided into two types: formed bellows and welded bellows. The bellows used in ultra-high vacuum system is generally made of SUS316 stainless steel.
In the ultra-high vacuum system, the bellows connecting the molecular pump and the mechanical pump are mostly formed bellows with NW flanges at both ends.
The advantages of the formed bellows are that they are simple to manufacture and low in cost. The disadvantage is that there is no insufficient flexibility. It is the welded bellows that compensates for the lack of formed bellows.