Patent attributes
A thermostatic mixing valve unit in an emergency wash unit has an integrated housing with cold and hot water inlets each having an associated check valve, and a tempered water discharge having a thermostat for cold/hot water mixing to provide a predetermined tempered water discharge. A high temperature limit valve responds to the water discharge temperature to permit or prevent hot water inflow when the water discharge exceeds a preset temperature. A cold water bypass valve is coupled by a diverter valve to the lower of the cold and hot water supply pressures to maintain a substantial water discharge flow when the high temperature limit valve restricts hot water flow or when the hot water check valve is stuck closed, or upon failure of the cold water supply as by sticking of the cold water check valve in a closed position or by a clogged filter screen.
