On demand sensor flush valve

An on demand, non-contact sensor controlled flush valve actuation system comprising:

• a flush valve having a valve body controlling the flow of water between a pressurized water supply and a plumbing fixture, said flush valve including a trip mechanism therein;
• an actuator assembly positioned within said flush valve and including a movable piston which is in fluid communication with a control water inlet therethrough;
• a control water conduit positioned external of said body having one end connected to said flush valve body and in constant fluid communication with the pressurized supply water;
• a normally closed solenoid operated control valve having an inlet port connected to the other end of said control water conduit and having an outlet port connected to said control water inlet of said actuator assembly;
• a radiation generating and sensing unit which immediately generates a first control signal in response to the return reflection of electromagnetic radiation generated therein, said sensing unit having a sensitivity range of four inches or less, so that only deliberate actions of a use will cause the return reflection of said electromagnetic signal;
• and
• a timer which receives first control signal and in response thereto immediately generates a second control signal of a predetermined duration, with said second control signal supplied to and activating said solenoid operated control valve, thereby opening said control valve and permitting a portion of said pressurized supply water to flow into said control water inlet and against said piston, with said piston moving from said pressurized supply water and moving said actuator assembly against the trip mechanism and opening the flush valve.