Patent ID: 6192813
Filing Date: 2001-02-27
Classification: A01C,G01F,Y02P

Abstract:
In an apparatus for dispensing, the apparatus comprising:a. an air distribution system comprising at least one tube for transporting air borne particles in a flow of air having a flow rate;b. an air flow source for providing a flow of air to the air distribution system;c. a controller operably connected to the air flow source for automatically effecting an adjustment of the flow rate;d. a particle velocity sensor located at the air distribution system for providing a sensor output signal indicative of a velocity of air borne particles in the tube, the particle velocity sensor including:i. an upstream light interruption sensor, including an optical transmitter and an optical receiver, located at the tube to detect particles at a first location in the tube; andii. a downstream light interruption sensor, including an optical transmitter and an optical receiver, located at the tube to detect particles at a second location in the tube, the second location being at a known distance downstream of the first location; ande. wherein the controller is operably connected to the sensor and to the air flow source, such that the controller automatically effects an adjustment of the flow rate by receiving a sensor output signal and automatically effecting an adjustment of the air flow source as a function of the sensor output signal and a target particle velocity value.