Bellows

Bellows consist of a corrugated flexible tube generally made of plastic, rubber or metal (stainless steel). Typical applications include the protection of moving components (e.g. bellows), compensating for differences in length (e.g. expansion joints) or use as a high-quality, maintenance-free stem seal for valves.
See Fig. 1 Bellows

Fig. 1 Bellows: Globe valve, stem sealed by bellows

 Fig. 1 Bellows: Globe valve, stem sealed by bellows

 

;