This type of sealing is made using a 98 Sh hardening elastomer with circular or delta section.

This configuration can be added to an insert that performs the function of a scraper (configuration recommended for fully welded valves).

The advantage of this seal is that it can be coupled to non-lapped balls while losing effectiveness with increasing and decreasing temperature and increasing pressure.

Delta with metal ring and thermoplastic insert

Delta with thermoplastic insert

Delta with metal ring