The RD valve is a wafer disk check valve for assembly between UNE-EN-558 Series 49 flanges.
This valve is to be used “all/nothing” (“on/off”). In other words, it must be completely opened, so it should never be used to regulate volume flow, since it was prematurely wear out the inner elements and lead to valve failure.
Available in standard materials such as Carbon Steel, AISI 316L, BRONZE, BRONZE ALUMINIUM, as well as special alloys AISI 904L, SUPERDUPLEX 5A, SUPERDUPLEX 6A, DUPLEX 4A, etc.