Metal Disc to metal seat. Non-metallic Disc to metal seat. Gage pressure in pounds per square inch. Parts that can be replaced or repaired without removing the valve body from the line. The pressure surge that occurs whenever liquid flow is suddenly arrested as by the quick closure of a valve.
Shock can occur also whenever reciprocating pumps are used in liquid carrying lines.
All bronze check valves shall be new, unused, and a currently standard products of an established manufacturer except for such deviations as may be required by this specification. Valves shall be free of all imperfections, defects, and hazards which might affect appearance, normal life, serviceability, or user safety. Valves shall be shipped complete, fully assembled, sealed and ready for immediate unpacking and installation. Parts and components not specifically mentioned in this specification, but which are required to provide a complete operating valve or which are standard for the model bid, shall be included. When no service application is specified, non-metallic discs shall be suitable for steam service.