Apparatus and method for measuring the real-time volumetric flow rate of grain in a field harvester using acoustical transducers

• US 5,837,906 A
• Filed: 06/09/1997
• Issued: 11/17/1998
• Est. Priority Date: 06/09/1997
• Status: Expired due to Fees

• Current Assignee: Ludwig Kipp
• Original Assignee: Ludwig Kipp
• Inventors: Palmer, John P.
• Primary Examiner(s): Chilcot, Richard
• Assistant Examiner(s): THOMPSON, JEWEL VERGIE
• Application Number:
  US08/871,443
• Time in Patent Office: 526 Days
• Field of Search: 73/861.73
• US Class Current: 73/861.73
• CPC Class Codes: A01D 41/1271 for measuring crop flow
• CPC Class Codes: G01F 1/66 by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters

Abstract

An apparatus and method for measuring the real-time volumetric flow rate of grain in a field harvester, comprising: a transmitting acoustical transducer for transmitting acoustic signals at a selected frequency, the transmitting acoustical transducer being disposed in the harvester with respect to a flow path of an airborne stream of grain during operation of the harvester so as to transmit the acoustic signals through the airborne stream of grain, whereby the transmitted acoustic signals are attenuated or scattered when passing through the airborne stream of grain; a receiving acoustical transducer for receiving the attenuated or scattered acoustic signals after passing through the flow path of the airborne stream of grain; and a computer in communication with the transmitting acoustical transducer and the receiving acoustical transducer for measuring the real-time volumetric flow rate of the airborne stream of grain as a function of the attenuation or scattering of the transmitted acoustic signals and a flow rate calibration characteristic dependent upon the moisture content of the airborne stream of grain; in an alternative embodiment, the transmitting and receiving acoustical transducers being located on the same side relative to the airborne stream of grain, and an acoustical reflector being disposed opposite the transducers to reflect transmitted acoustical signals from the transmitting acoustical transducer back to the receiving acoustical transducer.

Claims

1. An apparatus for measuring the real-time volumetric flow rate of grain in a field harvester, comprising:

a transmitting acoustical transducer for transmitting acoustic signals at a selected frequency, said transmitting acoustical transducer being disposed with respect to a flow path of an airborne stream of grain during operation of said harvester so as to transmit said acoustic signals through said airborne stream of grain, whereby said transmitted acoustic signals are attenuated when passing through said airborne stream of grain;

a receiving acoustical transducer for receiving said attenuated acoustic signals after passing through said flow path of said airborne stream of grain; and

computing means in communication with said transmitting acoustical transducer and said receiving acoustical transducer for measuring the real-time volumetric flow rate of said airborne stream of grain as a function of said attenuation of said transmitted acoustic signals and a flow rate calibration characteristic dependent upon the moisture content of said airborne stream of grain, whereby the real-time volumetric flow rate f is determined in accordance with the equation;

A=100*(1-e^-f/fo), where A is the percent attenuation and fo is a constant dependent upon said calibration characteristic.

2. The apparatus for measuring the real-time volumetric flow rate of grain as recited in claim 1, wherein said transmitting acoustical transducer is disposed on a first side of said airborne stream of grain and said receiving acoustical transducer is disposed on a second side of said airborne stream of grain opposite to said transmitting acoustical transducer.

3. The apparatus for measuring the real-time volumetric flow rate of grain as recited in claim 1, further comprising means for measuring said moisture content of said airborne stream of grain to provide said flow rate calibration characteristic, said means for measuring said moisture content of said airborne stream of grain communicating with said computing means.

4. The apparatus for measuring the real-time volumetric flow rate of grain recited in claim 1, wherein said acoustical transmitting transducer and said acoustical receiving transducer are disposed above a clean-grain hopper for collecting said airborne stream of grain.

5. An apparatus for measuring the real-time volumetric flow rate of grain in a field harvester, comprising:

a transmitting acoustical transducer for transmitting acoustic signals at a selected frequency, said transmitting acoustical transducer being disposed on a first side of a flow path of an airborne stream of grain during operation of said harvester so as to transmit said acoustic signals along a path through said airborne stream of grain, whereby said transmitted acoustic signals are attenuated when passing through said airborne stream of grain;

a receiving acoustical transducer for receiving said attenuated acoustic signals, said receiving acoustical transducer being disposed on said first side of said flow path of said airborne stream of grain;

an acoustically reflective surface disposed on a second side of said flow path of said airborne stream of grain for reflecting said transmitted acoustic signals back to said receiving acoustical transducer; and

computing means in communication with said transmitting acoustical transducer and said receiving acoustical transducer for measuring the real-time volumetric flow rate of said airborne stream of grain as a function of said attenuation of said transmitted acoustic signals and a flow rate calibration characteristic dependent upon the moisture content of said airborne stream of grain, whereby the real-time volumetric flow rate f is determined in accordance with the equation;

A=100*(1-e^-f/fo), where A is the percent attenuation and fo is a constant dependent upon said calibration characteristic.

6. The apparatus for measuring the real-time volumetric flow rate of grain as recited in claim 5, further comprising means for measuring said moisture content of said airborne stream of grain to provide said flow rate calibration characteristic, said means for measuring said moisture content of said airborne stream of grain communicating with said computing means.

7. A method for measuring the real-time volumetric flow rate of grain in a field harvester, comprising the steps of:

transmitting acoustic signals at a selected frequency from a transmitting acoustical transducer being disposed with respect to a flow path of an airborne stream of grain during operation of said harvester through said airborne stream of grain, whereby said transmitted acoustic signals are attenuated when passing through said airborne stream of grain;

receiving said attenuated acoustic signals with a receiving acoustical transducer after passing through said flow path of said airborne stream of grain; and

measuring the real-time volumetric flow rate of said airborne stream of grain as a function of said attenuation of said transmitted acoustic signals and a flow rate calibration characteristic dependent upon the moisture content of said airborne stream of grain, whereby the real-time volumetric flow rate f is determined in accordance with the equation;

A=100*(1-e^-f/fo), where A is the percent attenuation and fo is a constant dependent upon said calibration characteristic, with computing means in communication with said transmitting acoustical transducer and said receiving acoustical transducer.

8. A method for measuring the real-time volumetric flow rate of grain in a field harvester, comprising the steps of:

transmitting acoustic signals at a selected frequency from a transmitting acoustical transducer being disposed on a first side of a flow path of an airborne stream of grain during operation of said harvester through said airborne stream of grain, whereby said transmitted acoustic signals are attenuated when passing through said airborne stream of grain;

reflecting said transmitted acoustic signals with an acoustically reflective surface disposed on a second side of said flow path of said airborne stream of grain;

receiving said attenuated acoustic signals with a receiving acoustical transducer being disposed on said first side of said flow path of said airborne stream of grain; and

measuring the real-time volumetric flow rate of said airborne stream of grain as a function of said attenuation of said transmitted acoustic signals and a flow rate calibration characteristic dependent upon the moisture content of said airborne stream of grain, whereby the real-time volumetric flow rate f is determined in accordance with the equation;

A=100*(1-e^-f/fo), where A is the percent attenuation and fo is a constant dependent upon said calibration characteristic, with computing means in communication with said transmitting acoustical transducer and said receiving acoustical transducer.

9. An apparatus for measuring the real-time volumetric flow rate of grain in a field harvester, comprising:

a transmitting acoustical transducer for transmitting acoustic signals at a selected frequency, said transmitting acoustical transducer being disposed with respect to a flow path of an airborne stream of grain during operation of said harvester so as to transmit said acoustic signals through said airborne stream of grain, whereby said transmitted acoustic signals are scattered when passing through said airborne stream of grain;

a receiving acoustical transducer for receiving said scattered acoustic signals after passing through said flow path of said airborne stream of grain; and

computing means in communication with said transmitting acoustical transducer and said receiving acoustical transducer for measuring the real-time volumetric flow rate of said airborne stream of grain as a function of said scattering of said transmitted acoustic signals and a flow rate calibration characteristic dependent upon the size and density6 of the granules of said airborne stream of grain, whereby the real-time volumetric flow rate f is determined in accordance with the equation;

S=So*(1-e^-f/fo), where S is the received scattered signal density, So is the saturation value of scattering at high grain flow rates and fo is a constant dependent upon said calibration characteristic.

10. A method for measuring the real-time volumetric flow rate of grain in a field harvester, comprising the steps of:

transmitting acoustical signals at a selected frequency from a transmitting acoustical transducer being disposed in said harvester on the first side of a flow path of an airborne stream of grain during operation of said harvester so as to transmit the acoustic signals along a path through the airborne stream of grain, whereby said transmitted acoustic signals are scattered when passing through said airborne stream of grain;

receiving said scattered acoustic signals with a receiving acoustical transducer being disposed on a second side of the flow path of said airborne stream of grain, the location of which is such that said acoustical signal received by said receiving acoustical transducer is maximized in response to said scattered acoustic signals;

measuring the real-time volumetric flow rate of said airborne stream of grain as a function of the scattering of said acoustic signals and a flow rate calibration characteristic dependent upon the size and density of the granules of the airborne stream of grain, whereby the real-time volumetric flow rate f is determined in accordance with the equation;

S=So*(1-e^-f/f0), where S is the received scattered signal intensity, So is the saturation value of scattering at high grain flow rates, and fo is a constant dependent on the calibration characteristic.