Valve mechanism for a water operated waste disposal unit

A valve assembly for a water actuated waste disposal unit that includes an annular toroidal chamber with stop means therein and an operating piston slidably mounted in said toroidal chamber and connected with cutting means for cyclically rotating said cutting means in opposite directions, said toroidal chamber having water inlet means on each side of said stop means, comprising:

• a valve unit having source connection means for connection to a source of pressurized water and including a valve body having a control cylinder therein;
• chamber connecting passage means in said valve body communicating with said toroidal chamber;
• a control piston slidably disposed in said control cylinder and including a circumferential supply channel for providing supply water from said source connection means through first passage means in said valve body;
• a pair of circumferential exhaust channels on said control piston, one on each side of said circumferential supply channel and separated therefrom by land means on said control piston, and alternately connected by second passage means internally located in said control piston for exhausting water through third passage means in said valve body;
• a pilot cylinder in said valve body;
• a pilot piston slidably disposed in said pilot cylinder, said pilot piston having internal channels for mating with said first passage means in said valve body and diverting supply water alternately to opposite ends of said control cylinder, the opposite ends of said pilot cylinder being connected with said chamber connecting passage means whereby the pilot piston is responsive to differential pressure on opposite sides of said chamber connecting passage means;
• spaced apart pairs of openings on the circumference of said pilot piston for alternately aligning with said first passage means in said valve body, each of said pairs of openings communicating with a separate internal passage in said pilot piston;
• exhaust passages in said pilot piston for alternately aligning with exhaust passages in said valve body to exhaust water from each end of the said control cylinder;
• and
• biasing means for holding said pilot piston at each end of its reciprocating stroke, said biasing means preventing movement of said pilot piston between opposite ends of the pilot cylinder below a predetermined pressure.