US3724720A
Expired / Lapsed
US
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Digital mass flow control system
Assignee: TRON CORP K
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Filing: 1971-08-05
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Granted: 1973-04-03
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Expires: 1991-08-05
Abstract
Abstract The throughput of a conveyor belt is controlled by a motor whose speed is established by the instantaneous state of an up/down counter. The counter is incremented upwardly by setpoint pulses representative of the desired mass flow rate, and downwardly by feedback pulses from a rate multiplier representative of the actual mass flow rate. When the actual mass flow rate is equal to the setpoint flow rate, the average number of setpoint pulses will equal the average number of feedback pulses with the result that the state of the counter will be stable with time. Speed control means for the motor maintains the belt speed at a level dependent upon the state of the counter. A variation between the actual and desired mass flow rates is manifested by a change in the average number of feedback pulses which results in a change in the state of the counter. The resultant change in the motor speed and hence the belt speed restores the average number of feedback pulses to equality with the setpoint pulses thus restoring stability to the counter and restoring the actual mass flow rate to the setpoint rate.
Inventors
- 👤 K Bullivant
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 20:14
CPC Classifications
G; G05; G05D; G05D7/00; G05D7/06; G05D7/0605; G05D7/0611; B; B65; B65G; B65G47/00; G01; G01G; G01G11/00; G01G11/08; G01G11/12; G01G11/14; G01G11/16; G01G11/18; B65G2811/00; B65G2811/06; B65G2811/0673; B65G2811/0689; Y; Y10; Y10S; Y10S388/00; Y10S388/90; Y10S388/903; Y10S388/907; Y10S388/909; Y10S388/912
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
195 words
A digital volumetric flow control system for use with a motor driving a conveyor belt having means for feeding material onto the belt at a constant rate, said system comprising: first digital means for producing a digital signal in the form of a train of feedback pulses whose frequency is representative of the speed of said conveyor belt, each of said feedback pulses representing an increment of movement of said conveyor belt; set point means fOr generating a digital signal in the form of a train of pulses representative of the desired volumetric flow rate; second digital means responsive to the feedback pulses from said first digital means and set point pulses from said set point means for producing a digital control signal representative of the speed at which said motor must drive the belt in order to establish equality between the desired and the actual volumetric flow rate, said second digital means cancelling a set point pulse for each feedback pulse or vice versa, and being operative to store any excess set point or feedback pulses not cancelled; and speed control means responsive to said control signal for controlling the speed of said motor.
Claim 2
Dependent Claim
195 words
A digital volumetric flow control system for use with a motor driving a conveyor belt having means for feeding material onto the belt at a constant rate, said system comprising: first digital means for producing a digital signal in the form of a train of feedback pulses whose frequency is representative of the speed of said conveyor belt, each of said feedback pulses representing an increment of movement of said conveyor belt; set point means fOr generating a digital signal in the form of a train of pulses representative of the desired volumetric flow rate; second digital means responsive to the feedback pulses from said first digital means and set point pulses from said set point means for producing a digital control signal representative of the speed at which said motor must drive the belt in order to establish equality between the desired and the actual volumetric flow rate, said second digital means cancelling a set point pulse for each feedback pulse or vice versa, and being operative to store any excess set point or feedback pulses not cancelled; and speed control means responsive to said control signal for controlling the speed of said motor.
Claim 3
Dependent Claim
39 words
A digital volumetric flow control system according to claim 1 wherein said second digital means comprises an up/down counter, said up/down counter being counted up in response to set-point pulses and being counted down in response to feedback pulses.
Claim 4
Dependent Claim
192 words
A digital mass flow control system for use with a motor driving a conveyor belt having means for feeding material onto the belt, said system comprising: first digital means for producing a digital signal in the form of a train of feedback pulses whose frequency is representative of the actual mass flow rate of material on the said conveyor belt, each of said feedback pulses representing an increment of mass; setpoint means for generating a digital signal in the form of a train of pulses representative of the desired mass flow rate; second digital means responsive to the feedback pulses from said first digital means and set point pulses from said set point means for producing a digital control signal representative of the speed at which said motor must drive the belt in order to establish equality between the desired and the actual mass flow rate, said second digital means cancelling a set point pulse for each feedback pulse or vice versa, and being operative to store any excess set point or feedback pulses not cancelled; and speed control means responsive to said control signal for controlling the speed of said motor.
Claim 5
Dependent Claim
192 words
A digital mass flow control system for use with a motor driving a conveyor belt having means for feeding material onto the belt, said system comprising: first digital means for producing a digital signal in the form of a train of feedback pulses whose frequency is representative of the actual mass flow rate of material on the said conveyor belt, each of said feedback pulses representing an increment of mass; setpoint means for generating a digital signal in the form of a train of pulses representative of the desired mass flow rate; second digital means responsive to the feedback pulses from said first digital means and set point pulses from said set point means for producing a digital control signal representative of the speed at which said motor must drive the belt in order to establish equality between the desired and the actual mass flow rate, said second digital means cancelling a set point pulse for each feedback pulse or vice versa, and being operative to store any excess set point or feedback pulses not cancelled; and speed control means responsive to said control signal for controlling the speed of said motor.
Claim 6
Dependent Claim
88 words
A digital mass flow control system according to claim 3 wherein the digital signal produced by said setpoint means is a train of setpoint pulses whose average frequency is representative of the desired mass flow rate, and wherein said second digital means includes an up/down digital counter having a terminal to which applied pulses cause the counter to count upwardly and a terminal to which applied pulses cause the counter to count downwardly, said feedback and setpoint pulses being applied to respective terminals of said up/down digital counter.
Claim 7
Dependent Claim
52 words
A digital mass flow control system according to claim 4 wherein said second digital means includes gating means, said gating means disabling an output of the instantaneous state of said up/down counter below a predetermined count and enabling an output of the instantaneous state of said up/down counter above said predetermined count.
Claim 8
Dependent Claim
23 words
A digital mass flow control system according to claim 4 wherein the instantaneous state of said up/down counter constitutes said digital control signal.
Claim 9
Dependent Claim
42 words
A digital mass flow control system according to claim 6 wherein said speed control means includes a digital-to-analog converter responsive to the state of said up/down counter for converting said digital control signal to an analog signal that establishes the motor speed.
Claim 10
Dependent Claim
94 words
A digital mass flow control system according to claim 3 including weighing means associated with said conveyor belt for producing a digital signal representative of the instantaneous mass of material on said conveyor belt, encoder means associated with said conveyor belt for producing a digital signal representative of the instantaneous rate of movement of said conveyor belt, said first digital means being responsive to the digital signals of said weighing means and said encoder means for producing said digital signal representative of the instantaneous acTual mass flow rate of material on said conveyor belt.
Claim 11
Dependent Claim
30 words
A digital mass flow system according to claim 8 wherein said encoder means produces a pulse train whose instantaneous frequency is representative of the instantaneous speed of said conveyor belt.
Claim 12
Dependent Claim
55 words
Adigital mass flow system according to claim 9 wherein said encoder comprises a gear composed of a magnetic material and being provided with a plurality of teeth, said gear being mounted upon the shaft of said motor driving said conveyor belt and a magnetic pickup being mounted in proximity to said teeth of said gear.
Claim 13
Dependent Claim
55 words
A digital mass flow control system according to claim 9 wherein said weighing means includes a transducer for producing an analog signal representative of the instantaneous mass of material on said belt, and an analog-to-digital converter having a storage register whose contents constitute a digital representation of the instantaneous mass of material on said belt.
Claim 14
Dependent Claim
78 words
A digital mass flow control system according to claim 11 wherein said first digital means includes a rate multiplier having a pulse input terminal and level input terminals, said pulse input terminal being connected to the output of said encoder means, and said level input terminals being connected to said storage register of said converter, the output of said rate multiplier being a train of feedback pulses whose average frequency is representative of the actual mass flow rate.
Claim 15
Dependent Claim
17 words
A digital mass flow control system according to claim 12 wherein said converter is a digital voltmeter.
Claim 16
Dependent Claim
77 words
A digital mass flow control system according to claim 12 including means for scaling the output of said rate multiplier for producing a scaled digital signal in the form of a pulse train, each pulse of which represents a discrete increment of mass delivered by said conveyor belt, and a counter for counting the pulses produced by said scaling means whereby the state of said counter represents the total mass of material passed by said conveyor belt.
Claim 17
Dependent Claim
39 words
A digital mass flow control system according to claim 14 wherein means are provided to adjust the contents of said storage register of said converter to zero for a prdetermined input to said converter to provide a tare control.
Claim 18
Dependent Claim
38 words
A digital mass flow control system according to claim 15 wherein said counter for counting the pulses produced by said scaling means ia a bi-directional counter which receives a countup or a countdown signal from said converter means.
Claim 19
Dependent Claim
74 words
A digital mass flow control system according to claim 12 including a mass flow rate counter means, said mass flow rate counter means including a counter for repetitively counting the pulses at said output of said rate multiplier for predetermined periods of time, a storage register for storing the contents of said counter at the end of each predetermined period of time, and display means for displaying the count stored in said storage register.
Claim 20
Dependent Claim
145 words
A digital mass flow indicator system for use with a motor driven conveyor belt having means for feeding material onto the belt, comprising: weighing means associated with said conveyor belt for producing a digital signal representative of the instantaneous mass of material on said conveyor belt; encoder means associated with said conveyor belt for producing a digital signal in the form of a pulse train whose instantaneous frequency is representative of the instantaneous rate of movement of said conveyor belt; multiplier means responsive to the digital signals produced by said weighing means and said encoder means for producing a digital signal in the form of a pulse train; and means for scaling the pulse train digital signal produced by said multiplier means to produce a digital signal pulse train in which each pulse is representative of an increment of mass delivered by said conveyor belt.
Claim 21
Dependent Claim
145 words
A digital mass flow indicator system for use with a motor driven conveyor belt having means for feeding material onto the belt, comprising: weighing means associated with said conveyor belt for producing a digital signal representative of the instantaneous mass of material on said conveyor belt; encoder means associated with said conveyor belt for producing a digital signal in the form of a pulse train whose instantaneous frequency is representative of the instantaneous rate of movement of said conveyor belt; multiplier means responsive to the digital signals produced by said weighing means and said encoder means for producing a digital signal in the form of a pulse train; and means for scaling the pulse train digital signal produced by said multiplier means to produce a digital signal pulse train in which each pulse is representative of an increment of mass delivered by said conveyor belt.
Claim 22
Dependent Claim
55 words
A digital mass flow indicator system according to claim 18 wherein said weighing means includes a transducer for producing an analog signal representative of The instantaneous mass of material on said belt, and an analog-to-digital converter having a storage register whose contents constitute a digital representation of the instantaneous mass of material on said belt.
Claim 23
Dependent Claim
77 words
A digital mass flow indicator system according to claim 19 wherein said multiplier means is a rate multiplier having a pulse input terminal and level input terminals, said pulse input terminal being connected to the output of said encoder means, and said level input terminals being connected to said storage register of said converter, the output of said multiplier being a digital signal representative of the instantaneous actual mass flow rate of material on said conveyor belt.
Claim 24
Dependent Claim
17 words
A digital mass flow indicator system according to claim 20 wherein said converter is a digital voltmeter.
Claim 25
Dependent Claim
39 words
A digital mass flow indicator system according to claim 20 including a counter for counting the pulses produced by said scaling means whereby the state of said counter represents the total mass of material passed by said conveyor belt.
Claim 26
Dependent Claim
39 words
A digital mass flow indicator system according to claim 22 whwerein means are provided to adjust the contents of said storage register of said converter to zero for a predetermined input to said converter to provide a tare control.
Claim 27
Dependent Claim
38 words
A digital mass flow indicator system according to claim 23 wherein said counter for counting the pulses produced by said scaling means is a bi-directional counter which receives a countup or a countdown signal from said converter means.
Claim 28
Dependent Claim
74 words
A digital mass flow indicator system according to claim 20 including a mass flow rate counter means, said mass flow rate counter means including a counter for repetitively counting the pulses at said output of said rate multiplier for predetermined periods of time, a storage register for storing the contents of said counter at the end of each predetermined period of time, and display means for displaying the count stored in said storage register.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-02 | 1976-10-02 | 1977-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-02 | 1980-10-02 | 1981-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-02 | 1984-10-02 | 1985-04-03 | $7700.00 | Window Closed / Lapsed |