What are the types and characteristics of vacuum bellows?
The picture shows the use of forming vacuum bellows
Vacuum bellows are usually divided into formed vacuum bellows and welded vacuum bellows. The material of vacuum bellows used in ultra-high vacuum systems is generally SUS316 stainless steel.
To make a formed vacuum bellows with a slightly larger caliber, first roll the stainless steel sheet into a cylindrical shape, and weld the joints. The cylinder is inserted into the vacuum bellows mold, and the vacuum bellows is formed by hydraulic pressure.
In the ultra-high vacuum system, the vacuum bellows connecting the molecular pump and the mechanical pump are mostly formed vacuum bellows with NW flanges at both ends.
The advantages of forming vacuum bellows are simple manufacture and low cost. The disadvantage is insufficient expansion and flexibility. To make up for the shortage of the formed vacuum bellows is the welded vacuum bellows.
Welded vacuum bellows is a thin-walled corrugated hose formed by welding circular stainless steel sheets with alternating inner and outer diameters (Figure 2). The welding method is plasma welding. This vacuum bellows has great flexibility and is an indispensable part in the connection of ultra-high vacuum systems and various motion introducers. Reasonably choose the natural length of the vacuum bellows, and the service life can reach hundreds of thousands of times.