This invention pertains to pressure relief valves of the type that are particularly suited for use on mobile tanks, such as railway tank cars.
U.S. Pat. No. 5,855,225 discloses a valve assembly that includes a base plate which carries a plurality of spring assemblies connected to a valve stem to permit a valve disc to open in response to overpressures.
In actual practice, such base plates have been cast of stainless steel to have precisely located mounting lugs for accurate placement of the spring assemblies. They also have cast opposed valve guides. Molding, and post-molding machining, necessary to form the valve guides, and to place the spring assemblies accurately, is expensive.
To reduce these costs, the present invention provides a valve plate of rolled stainless steel and a novel spring assembly bracket and valve guide that is particularly suited for being welded to the valve plate.