Abstract
A control for a batch bin and a continuous loss bin system having a separate weight measuring device for each bin whose sum at transfer is used to establish continuously digitally desired weights at fixed intervals to be compared with the actual weight in the continuous loss bin to provide an error signal for a continuous feeder.
Filing date: Apr 14, 1977
Issue date: Sep 5, 1978
Inventors: William H. Ward, Henry F. Henderson, Jr., Kenneth H. Kardux
Assignee: H. F. Henderson Industries
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What is claimed is:
1. In a material feeding apparatus having a first storage means for storing a preselected weight of material, a transfer means at the outlet of said first storage means, a second storage at the outlet of said transfer means for storing material, a continuous feed means at the outlet of said second storage means and control means for operating said transfer means and said continuous feed means the improvement being said control means which comprises:
- first measuring means for measuring the weight of material in said first storage means;
- second measuring means for continuously measuring the weight of material in said second storage means;
- logic means for providing a control signal for said continuous feed means as a function of the weight measurement of said second measuring means relative to the sum of weight measurements of said first and second measuring means prior to opening of said transfer means.
2. The material feeding apparatus according to claim 1 wherein said logic means includes digital weight prediction means responsive to weight measurements of said first and second measuring means to provide desired weights at specific time intervals and a means for comparing said desired weights and weight measurements of said second measuring means to produce said control signal for said continuous feed means.
3. The material feeding apparatus according to claim 2 wherein said weight prediction means includes means for digitally storing weight measurments from said first and second measuring means immediately prior to said transfer means opening and means for decrementing said storing means to provide said desired weights.
4. The material feeding apparatus according to claim 2 wherein said weight prediction means includes a down counter for storing sum of weight measurements from said first and second measuring means, means for counting down said counter at a fixed rate and a digital to analog converter for converting the contents of said down counter to said desired weight for a desired feeding rate.
5. The material feeding apparatus according to claim 4 wherein said comparing means includes an analog comparator for comparing said desired weight with the weight measurement from said second measuring means and said countdown means includes a variable reference for modifying said desired weight as a function of a desired feeding rate.
6. The material feeding apparatus according to claim 2 wherein said comparing means includes a sample and hold means for holding said control signal for said continuous feed means at a fixed value during said transfer.
7. The material feeding apparatus according to claim 6 including timing means responsive to a low weight signal from said second measuring means for activating said transfer means and said sample and hold means for a fixed period of time.
8. A control system for material feeding apparatus comprising:
- first means for measuring the weight of a batch supply;
- second means for measuring the weight of a continuous loss supply;
- means for transferring said batch supply to said continuous loss supply;
- logic means for continuously providing a desired weight signal at fixed intervals based on the sum of the signals of said first and second measuring means immediately prior to said batch supply being transferred to said continuous loss supply; and
- means for providing a weight error signal responsive to said desired weight signal and said signal of said second measuring means.
9. A control system according to claim 8 wherein said logic means includes means for digitally storing the sum of signals from said first and second measuring means immediately prior to said transfer and means for continuously decrementing said digital storage means at a rate sufficient to provide desired weight signals at said fixed intervals.
10. A control system according to claim 9 wherein said logic means further includes a digital to analog converter for converting the decremental sum to an analog desired weight signal and wherein said error means includes analog means for comparing said desired weight signal with the weight signal from said second measuring means to provide said weight error signals.
11. A control system according to claim 10 wherein said error means includes means connected to the output of said analog comparing means for sampling the output of said analog comparing means and holding the sampled value during said transfer.
12. A control system according to claim 9 wherein said digital storage means includes a down counter and said logic means includes means for summing said signals from said first and second measuring means and means for inserting the sum from said summing means to said digital storage means at a preselected value of said signal of said second measuring means.
13. A control system according to claim 12 wherein said decrementing means includes a means for producing pulses and means for accumulating said pulses to produce said decrementing at said fixed interval, and said inserting means receives pulses from said accumulating means to insert said sum between one of said fixed intervals.
14. A control system according to claim 12 wherein said error means includes means for sampling and holding said weight error signal and wherein said logic means includes a timing means for providing a batch transfer signal and a sample and hold signal for a fixed period of time in response to said preselected value of said signal of said second measuring means.