Mixing valve

A mixing valve for mixing a first relatively hotter fluid and a second relatively colder fluid, the mixing valve comprising

• a valve body including a cold fluid inlet, a hot fluid inlet, a mixed fluid outlet, a cavity wherein fluid from the cold and hot fluid inlets flow together, the cavity having an upstream region and a downstream region, the downstream region being between. the upstream region and the mixed fluid outlet, a first seat disposed in the upstream region, and a second seat disposed in the downstream region;
• a thermostat assembly including a thermostat responsive to the temperature of the mixed fluid, the assembly movable between an extended position when the thermostat senses a relatively higher temperature and a retracted position when the thermostat senses a relatively lower temperature;
• and
• a valve member in the valve body movable in response to movement of the thermostat assembly between a first position engaging the first seat when the thermostat senses a first mixed fluid temperature, and a second position engaging the second seat, in the first position the valve member blocking the hot fluid inlet, the valve member moving to the second position in response to failure of the thermostat, and the valve member moving to a third position between the first and second seats when a second mixed fluid temperature lower than the first mixed fluid temperature is sensed by the thermostat, wherein the valve member blocks the cold inlet.

A mixing valve comprising

• a valve body providing a first fluid inlet, a second fluid inlet, a mixed fluid outlet, and a cavity having a longitudinal axis, the cavity defined by at least one internal wall, and the cavity being in commodification with the inlets and the outlet,
• a first valve seat extending from the at least one internal wall,
• a second valve seat extending from the at least one internal wall, and
• a piston in the cavity and movable along the axis, the piston including a piston bore extending longitudinally therethrough and having a first piston end, a second piston end, a middle region between the ends, an engagement surface at the first piston end bordering the piston bore and engaging the first seat to block flow of the first fluid through the piston bore, a failure shutoff surface at the second piston end movable to engage the second valve seat, the first fluid entering the piston bore between the first valve seat and the engagement surface, the piston formed to include a slot therein positioned axially closer to the engagement surface than to the failure shutoff surface to facilitate mixing of the first and second fluids.