Weigh feeder system

• US 4,054,784 A
• Filed: 04/19/1976
• Issued: 10/18/1977
• Est. Priority Date: 06/18/1975
• Status: Expired due to Term

• Current Assignee: Acrison, Inc.
• Original Assignee: Angelo Ferrara, Joseph L. Hartmann, Ronald J. Ricciardi
• Inventors: Ricciardi, Ronald J., Ferrara, Angelo, Hartmann, Joseph L.
• Primary Examiner(s): Wise, Edward J.
• Application Number:
  US05/678,391
• Time in Patent Office: 547 Days
• Field of Search: 235/151.33, 235/151.34, 222/52, 222/55, 222/59, 222/71, 222/77, 222/58, 177/105
• US Class Current: 700/240
• CPC Class Codes: G01G 11/12 by controlling the speed of the belt
• CPC Class Codes: G05D 7/0605 specially adapted for solid materials

Abstract

Disclosed herein is an automatically controlled weigh feeding apparatus including a container prefilled with a substance, a device for discharging the substance from the container at a controllable rate, apparatus for weighing the container and its contents and for producing an electrical signal proportional to that weight, a first amplifier for amplifying the electrical signal, a first analog-digital converter coupled to said first amplifier and a digital computer coupled to said first analog-digital converter for computing the weight of substance remaining in the container. A second amplifier is coupled to said first amplifier and a ramp off-set circuit which is controlled by the digital computer inputs a second signal to the second amplifier means having a controlled stepping output applied as a second input signal to the second amplifier to maintain the output of the second amplifier within a given selected range of amplitude during one time cycle of operation. A second analog-digital converter interposed between the second amplifier and the digital computer. The digital computer is adapted to compute a corrective signal based on the signal received for controlling the discharge of the substance from the container.

Claims

1. A weigh feeding apparatus comprising a container for a prefilled substance, means for discharging said substance from said container at a controllable rate;

means for weighing said container prefilled with said substance;

means coupled to said weighing means for producing a first electrical signal proportional in amplitude to the weight determined by said weighing means;

high gain amplifier means for amplifying said first electrical signal, an analog-digital converter coupled to said amplifier means, digital computer means coupled to said analog-digital converter for computing and outputting a signal corresponding to the signal received, digital-analog converter ramp offset means controlled by said computer output signal, having a controlled stepping output applied as a second input signal to said amplifier means to algebraically combine with said first electrical signal, each step corresponding to one time cycle of operation thereby to maintain the output of said amplifier in a given preselected range of amplitude during said one time cycle of operation, said computer means being adapted to compute a corrective signal based on said signal received, and means coupled between said computer means and said means for discharging said substance from said container for controlling the rate of discharge responsive to said corrective signal.

2. A weigh feeding apparatus according to claim 1 further comprising means for inputting into said computer means a preselected feed rate, said computer means being adapted to store in memory a series of said signals received from said analog-digital converter for each of said time cycles of operation and computing said corrective signal by comparing said signals received with said preselected feed rate.

3. A weigh feeding apparatus according to claim 2 wherein said computer means is adapted to maintain said corrective signal constant during the time when a preselected number of said signals received from said analog-digital converter exceeds preselected upper or lower limits, during one time cycle of operation.

4. A weigh feeding apparatus according to claim 2 wherein said computer means is further adapted to compute said corrective signal disregarding a preselected number of said signals received from said analog-digital converter exceeding preselected upper or lower limits, during one time cycle of operation, when computing said corrective signal.

5. A weigh feeding apparatus according to claim 2 further comprising means for correcting said signal received to compensate for errors due to extraneous noise.

6. A weigh feeding apparatus according to claim 5 wherein said means for correcting said signal received includes shaft encoder means coupled between said means for discharging said substance from said container and said digital computer means.

7. A weigh feeding apparatus comprising a container for a prefilled substance, means for discharging said substance from said container at a controllable rate;

means for weighing said container prefilled with said substance;

means coupled to said weighing means for producing a first electrical signal proportional in amplitude to the weight determined by said weighing means;

first amplifier means for amplifying said first electrical signal, a first analog-digital converter coupled to said first amplifier means, digital computer means coupled to said first analog-digital converter for computing a first output signal corresponding to the weight of said substance in said container, second amplifier means for amplifying the signal received from said first amplifier means, a second analog-digital converter coupled to said second amplifier means, said digital computer means being coupled to said second analog-digital converter, said couputer means being adapted to compute a corrective signal based on said signal received from said second analog-digital converter, and means coupled between said computer means and said means for discharging said substance from said container for controlling the rate of discharge responsive to said corrective signal.

8. A weigh feeding apparatus according to claim 7 further comprising under-weight limit input means to said computer means, and over-weight limit input means to said computer means, said computer means being adapted to actuate alarm means when said signals received from said first analog-digital converter exceed one of said limits.

9. A weigh feeding apparatus according to claim 7 further comprising means for inputting into said computer means a preselected feed rate, said computer means being adapted to integrate said preselected feed rate with respect to time and output a display corresponding to the desired total feed commanded, said computer means being further adapted to integrate the actual total weight of material fed as determined by the signal received from said first analog digital converter means and, by comparing said total feed commanded to said actual total weight of material fed, adjust said corrective signal.

10. A weigh feeding apparatus according to claim 7 further comprising means for inputting into said computer means a preselected feed rate, said computer means being adapted to store in memory a series of said signals received from said second analog-digital converter means for each of said time cycles of operation and compute said corrective signal by comparing said signals received with said feed rate;

electrically actuated means for refilling said container, means for inputting into said computer means a preselected low level of value corresponding to the desired minimum level of substance in said container;

means for inputting into said computer means a preselected out of low level value corresponding to the desired maximum level of substance in said container;

said computer means being adapted to compare the actual weight of substance in said container as determined by the signal received from said first analog-digital converter means with the preselected low level value and when said values coincide search said corrective signal until said corrective signal is within preselected deviation limits, and when the corrective signal is within said preselected limits, acutating said means for refilling said container while maintaining said corrective signal constant, and when the actual weight of sbustance in said container as determined by the signal received from said first analog-digital converter reaches said preselected out of low level value, said means for refilling said container being disengaged and said corrective signal being again actuated.

11. A weigh feeding apparatus according to claim 7 wherein said means for discharging said substance from said container comprises an electric motor, means interconnecting said motor with said computer means to input into said computer means the rotational speed of said motor, and input means to said computer means to preselect a desired rotation speed of said motor, switching input means for said computer means to selectively control said corrective signal by comparing the actual motor speed with the desired motor speed.

12. A weigh feeding apparatus comprising a container for a prefilled substance, means for discharging said substance from said container at a controllable rate;

means for weighing said container prefilled with said substance;

means coupled to said weighing means for producing a first electrical signal proportional in amplitude to the weight determined by said weighing means;

first amplifier means for amplifying said first electrical signal, a first analog-digital converter coupled to said first amplifier means, digital computer means coupled to said first analog-digital converter for computing a first output signal correspnding to the weight of said substance in said container, second amplifier means for amplifying the signal received from said first amplifier means, a second analog-digital converter coupled to said second amplifier means, said digital computer means being coupled to said second analog-digital converter for computing and outputting a signal corresponding to the input signal received from said second analog-digital converter, digital-analog converter ramp offset means, controlled by said second computer output signal, having a controlled stepping output applied as a second input signal to said second amplifier means to algebraically combine with said input to said second amplifier means form said first amplifier means, each step corresponding to one time cycle of operation thereby to maintain the output of said second amplifier in a given preselected range of amplitude during said one time cycle of operation, said computer means being adapted to compute a corrective signal based on said signal received from said second analog-digital converter, and means coupled between said computer means and said means for discharging said substance from said container for controlling the rate of discharge responsive to said corrective signal.

13. A weigh feeding apparatus according to claim 12 further comprising means for inputting into said computer means a preselected feed rate value, said computer means being adapted to store in memory a series of said signals received from said second analog-digital converter for each of said time cycles of operation and computing said corrective signal by comparing said signals received with said preselected feed rate value.

14. A weigh feeding apparatus according to claim 12 wherein the output from said first amplifier means ranges between about -10 volts when the container is full to about +10 volts when the container is empty.

15. A weigh feeding apparatus according to claim 12 wherein the output from said second amplifier means ranges between about +5 volts and -5 volts during one time cycle of operation.

16. A weigh feeding apparatus comprising container means, means for discharging a substance from said container means at a controllable rate, means for detecting the weight of the substance being discharged from said container means, means coupled to said detecting means for producing electrical signals proportional to the weight determined by said detecting means, an analog-digital converter for receiving said electrical signals, digital computer means coupled to said analog-digital converter for computing a corrective signal based on the signals received, means coupled between said computer means and said means for discharging said substance from said container for controlling the rate of discharge responsive to the corrective signal, means for inputting into said computer means a preselected feed rate, said computer means being adapted to store a series of the signals received from said analog-digital converter for a time cycle of operation and computing said corrective signal by comparing said signals received with said preselected feed rate, said computer means being adapted to maintain said corrective signal constant during the time when a preselected number of said signals received from said analog-digital converter exceeds preselected upper or lower limits, during one time cycle of operation.

17. A weigh feeding apparatus according to claim 16 wherein said computer means is further adapted to compute said corrective signal disregarding a preselected number of said signals received from said analog-digital converter exceeding preselected upper or lower limits, during one time cycle of operation, when computing said corrective signal.

18. A weigh feeding apparatus according to claim 16 further comprising means for correcting said signal received to compensate for errors due to extraneous noise.

19. A weigh feeding apparatus according to claim 16 wherein said means for correcting said signal received includes shaft encoder means coupled between said means for discharging said substance from said container and said digital computer means.

20. A weigh feeding apparatus comprising a container for prefilling with a substance, means for discharging said substance from said container at a controllable rate, means for weighing said container prefilled with said substance, means coupled to said weighing means for producing electrical signals proportional to the weight determined by said weighing means, an analog-digital converter for receiving said electrical signals, digital computer means coupled to said analog-digital converter for computing a corrective signal based on the signals received, means coupled between said computer means and said means for discharging said substance from said container for controlling the rate of discharge responsive to the corrective signal, means for inputting into said computer means a preselected feed rate, said computer means being adapted to store a series of the signals received from said analog-digital converter for a time cycle of operation and computing said corrective signal by comparing said signals received with said preselected feed rate, said computer means being adapted to maintain said corrective signal constant during the time when a preselected number of said signals received from said analog-digital converter exceeds preselected upper or lower limits, during one time cycle of operation.