Thermostatic mixing valve

Abstract

The invention provides a thermostatic mixing valve for use within a water discharge fixture. The mixing valve comprises a cover defining an interior region, a stationary lower disk residing within the interior region, and a moveable upper disk. The lower and upper disks each have a central opening and at least one peripheral groove, wherein the grooves are alignable to form a peripheral water outlet. The mixing valve also includes a spindle assembly extending through the cover region and operably connected to the upper disk to enable alignment of the grooves and formation of the water outlet. A pressure relief cavity is formed between the spindle assembly and the cover, and wherein water flows through an opening in the spindle assembly and into the relief cavity. In order to reduce friction during operation of the valve, the water in the pressure relief cavity applies downward pressure to the spindle assembly which counter-balances upward pressure applied to the spindle assembly by water flowing through the lower and upper disks. The mixing valve further includes a slide bolt and a mixer, wherein depending upon the selected discharge water temperature, water from the cold and hot water cavities flows through the slide bolt into the mixer for subsequent discharge through the fixture.