Patent ID: 6568655
Filing Date: 2003-05-27
Classification: E03C,E03D,G01S,Y10T

Abstract:
A fluid flow control device comprising:an actuator for controlling fluid flow; a radio frequency transmitter configured and arranged to produce a plurality of bursts of pulses, wherein each burst comprises two or more substantially uniformly-spaced pulses of radio frequency energy having a frequency to form a sensor field, the pulses being transmitted at a pulse rate, wherein a time space between adjacent bursts is greater than the pulse rate; a receiver gated open after transmission of each pulse to receive radio frequency energy reflected by objects within the sensor field determined by a delay time between transmission of each pulse and gating open the receiver; a processor coupled to the gated receiver for evaluating the reflected radio frequency energy, wherein the processor is coupled to the actuator and is configured and arranged for activating the actuator in response to the reflected radio frequency energy.