The following U.S. patents are known:
U.S. Pat. No. 3,313,312 issued April 11, 1967 to W. E. Weese, disclosed a resettable immersion type thermally responsive fluid valve; this evidently would be able to shut off hot water if suitable material were used;
U.S. Pat. No. 3,659,624 issued May 2, 1972 to W. M. Kelly, disclosed another form of valve with fusible link and external sensor;
U.S. Pat. Nos. 3,690,336 issued Sept. 12, 1972 to E. W. Drum and 2,720,220 issued Mar. 13, 1973 to J. A. McMatch, disclosed two forms of thermally responsive ball type shut-off valves. With suitable material substitution either of these valves could evidently be used to set a limit on temperature of water flowing though them.