Thermostatic mixing faucet having improved stability

A thermostatic mixing valve having a cold water inlet port and a hot water inlet port including:

• a base having two supply ports;
• a rotatable handle body mounted onto said base and operably connected to a first valving surface with a hot water and cold water inlet passage therethrough that are operably positioned adjacent said two supply ports for controlling volume flow into said housing;
• a thermostat element operably connected to a movable second valving surface that is movable between first and second seats for controlling the relative flow from the cold and hot water inlet passages in response to the temperature of fluid in a mixing chamber;
• said ports and said first valving surface being incorporated in two concentrically mounted plates that can be rotated with respect to each other and provided with openings therethrough for the controlled passage of the fluid through the two plates;
• said thermostatic mixing valve characterized by:
• at least one opening in one of said valve plates, is formed with two distinct fields so as to subdivide the entire field of regulation determined by the relative rotation of the plates into at least two successive fields, the first field of regulation, adjacent to the shut off position, being determined by an inlet passage aperture first section of restricted flow and the second field of regulation, after the first, formed by an enlarged cross section;
• and
• a discrete third intermediate field of regulation interposes between said first and second sections.