To keef,
The Edwards valve company has a good product line of steam valves, including the non-return valve for a boiler steam drum. They have a sizing calculation to ensure disk full opening to avoid flutter of disk at turndown flows. You might be better off with a stop check valve of one or two sizes smaller than pipe size.
Common globe valves are available up to size DN300. The Edwards products have CL600 to size DN800 (NPS 32") and the CL2500 valves to size DN600.
Edwards valve company is now part of the FLOWSERVE Corp.,