CPC A01D 41/1276 (2013.01) [A01D 41/1272 (2013.01); A01F 12/181 (2013.01); A01F 12/28 (2013.01); A01F 12/444 (2013.01); A01F 12/448 (2013.01); A01F 12/48 (2013.01); A01F 12/52 (2013.01); G01P 5/248 (2013.01)] | 20 Claims |
1. A grain cleaning system comprising:
a screening apparatus having a duct and a sieve disposed in the duct;
a fan arranged to generate a cleaning airstream through the duct;
an ultrasonic sensing device comprising:
a transmitter configured to transmit a base signal through the cleaning airstream; and
a receiver spaced from the transmitter and configured to receive and transduce a modified signal that comprises a modified portion of the base signal and;
an electronic control unit (ECU) that is in communication with the sensing device, wherein the ECU is configured to generate control signals based upon a phase shift value which is determined from a parameter of the base signal and a parameter of the modified signal,
wherein the receiver is configured to transduce a signal reflected off of airborne particles in the cleaning airstream, and wherein the ECU is configured to generate a value for the particle velocity from a Doppler frequency which is determined from a frequency of the base signal and a frequency of the reflected signal.
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