USRE30684E - Digital mass flow control system - Google Patents

Digital mass flow control system Download PDF

Info

Publication number
USRE30684E
USRE30684E US05/564,965 US56496575A USRE30684E US RE30684 E USRE30684 E US RE30684E US 56496575 A US56496575 A US 56496575A US RE30684 E USRE30684 E US RE30684E
Authority
US
United States
Prior art keywords
digital
counter
mass flow
pulses
conveyor belt
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US05/564,965
Other languages
English (en)
Inventor
Kenneth W. Bullivant
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
K Tron Technologies Inc
Original Assignee
K Tron International Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by K Tron International Inc filed Critical K Tron International Inc
Priority to US05/564,965 priority Critical patent/USRE30684E/en
Application granted granted Critical
Publication of USRE30684E publication Critical patent/USRE30684E/en
Publication of USRE30684F1 publication Critical patent/USRE30684F1/en
Anticipated expiration legal-status Critical
Assigned to K-TRON TECHNOLOGIES, INC., A CORP. OF DE reassignment K-TRON TECHNOLOGIES, INC., A CORP. OF DE ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: K-TRON INTERNATIONAL, INC., A CORP. OF NJ
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D7/00—Control of flow
    • G05D7/06—Control of flow characterised by the use of electric means
    • G05D7/0605—Control of flow characterised by the use of electric means specially adapted for solid materials
    • G05D7/0611—Control of flow characterised by the use of electric means specially adapted for solid materials characterised by the set value given to the control element
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65G—TRANSPORT OR STORAGE DEVICES, e.g. CONVEYORS FOR LOADING OR TIPPING, SHOP CONVEYOR SYSTEMS OR PNEUMATIC TUBE CONVEYORS
    • B65G47/00—Article or material-handling devices associated with conveyors; Methods employing such devices
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01G—WEIGHING
    • G01G11/00—Apparatus for weighing a continuous stream of material during flow; Conveyor belt weighers
    • G01G11/08—Apparatus for weighing a continuous stream of material during flow; Conveyor belt weighers having means for controlling the rate of feed or discharge
    • G01G11/12—Apparatus for weighing a continuous stream of material during flow; Conveyor belt weighers having means for controlling the rate of feed or discharge by controlling the speed of the belt
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01G—WEIGHING
    • G01G11/00—Apparatus for weighing a continuous stream of material during flow; Conveyor belt weighers
    • G01G11/14—Apparatus for weighing a continuous stream of material during flow; Conveyor belt weighers using totalising or integrating devices
    • G01G11/16—Apparatus for weighing a continuous stream of material during flow; Conveyor belt weighers using totalising or integrating devices being electrical or electronic means
    • G01G11/18—Apparatus for weighing a continuous stream of material during flow; Conveyor belt weighers using totalising or integrating devices being electrical or electronic means using digital counting
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65G—TRANSPORT OR STORAGE DEVICES, e.g. CONVEYORS FOR LOADING OR TIPPING, SHOP CONVEYOR SYSTEMS OR PNEUMATIC TUBE CONVEYORS
    • B65G2811/00—Indexing codes relating to common features for more than one conveyor kind or type
    • B65G2811/06—Devices controlling the relative position of articles
    • B65G2811/0673—Control of conveying operations
    • B65G2811/0689—Releasing constant material flow

Definitions

  • This invention relates to a digital mass flow control system for establishing and maintaining a preselected throughput of a motor driven conveyor belt.
  • Conventional digital mass flow control system may include a transducer and an analog-to-digital (A/D) convertor associated with the conveyor belt for providing an indication of the instantaneous mass on the conveyor belt, and a setpoint generator for establishing the desired throughput (e.g., mass per unit time) of the system.
  • the desired throughput or the setpoint of the system is established by the average frequency of the setpoint pulses produced by the setpoint generator.
  • These pulses are counted in a counter of a digital comparator which produces an output pulse when the count reaches a value determined by the contents of a storage register whose state is established by the output of the A/D convertor.
  • the output pulse serves to clear the counter and increment the stepping motor that drives the belt whereby the latter is also incremented.
  • the primary object of the present invention is to provide a novel digital mass flow control system capable of achieving the results just described.
  • variable speed motor to drive the belt wherein the speed of the motor is established by the instantaneous state of an up/down counter.
  • the counter is incremented upwardly by setpoint pulses representative of the desired flow rate, and downwardly by feedback pulses from a rate multiplier representative of the actual mass flow rate.
  • the pulse input to the rate multiplier is a train of pulses whose instantaneous frequency is a function of the instantaneous belt speed, and is derived from an encoder responsive to rotation of the conveyor belt pulley.
  • the level input to the rate multiplier which establishes the fraction of the count passed by the multiplier, is derived from an A/D converter whose input is a signal produced by a transducer that measures the instantaneous mass of material on the belt of the conveyor.
  • the output of the rate multiplier is thus a train of feedback pulses whose number per unit time is representative of and may serve as an indication of the actual mass flow rate of material. These feedback pulses increment the counter downwardly.
  • FIG. 1 is a schematic view in elevation of a feeder into which the present invention may be incorporated;
  • FIG. 2 is a schematic plan view of the feeder shown in FIG. 1 with portions broken away for purposes of illustration;
  • FIG. 3 is an electrical schematic diagram showing details of the control circuit.
  • Feeder 10 includes a structural base 11, conveyor belt system 12, and drive means 13 operatively associated with the conveyor belt system.
  • System 12 includes conveyor belt 14 and hopper feeder 15.
  • Conveyor belt 14 comprises a pair of spaced longitudinally extending support members-16 rigidly connected to the structural base 11 of the feeder, and providing at the end adjacent hopper 15, a rigid support for a pair of laterally spaced bearings 17 on which is rotatably mounted drive pulley 18 carrying endless belt 19 upon which is deposited dry granular material from hopper 15.
  • Pivotally mounted at the opposite end of support member 16 is a pair of attached 20 upon which is rotatably mounted another pulley 21.
  • Belt 19 rides over each of pulleys 18 and 21, with tension being provided by belt tension means 22.
  • One end of tension means 22 is attached to support member 16, and the other end is attached to a bearing 20 at a point remote from its pivotal connection to support 16.
  • Drive means 13 comprises electric motor 23 attached to structural base 11, and speed reducer means 24 by which the output of the electric motor is coupled to the drive pulley 18 of the conveyor belt system.
  • motor 23 is a D.C. device with a permanent magnet field.
  • the speed of motor is controlled by changing armature current. Increasing the armature current speeds up the motor; and decreasing the armature current slows down the motor.
  • control system 26 comprises weighing means 27 and encoder means 28 associated with belt 19, first digital means 29 responsive to the digital signals of the weighing means and the encoder means for producing feedback pulses representative of the actual mass flow rate, setpoint means 30 for producing setpoint pulses representative of the desired mass flow rate, second digital means 31 responsive to the feedback and setpoint pulses, and control means 32 associated with motor 23 for controlling its speed.
  • Weighing means 27 comprises transducer or load cell 33 and an analog-to-digital convertor in the form of digital voltmeter 34.
  • Transducer 33 is rigidly attached to support member 16 of the conveyor belt system and includes a detector arm 35 which is in operative contact with belt 19.
  • Transducer 33 is conventional and well known in the art, and may be a Type 407000 load cell manufactured by K-Tron Corporation. The weight of the material on the belt causes arm 35 to be deflected, and transducer 33 responds by producing an analog signal representative of the instantaneous mass of material on belt 19.
  • Digital voltmeter 34 includes a storage register whose state is established by the level of the analog signal produced by transducer 33. Such state is the digital representation of the instantaneous mass of the material on the belt, and this value can be visually displayed by reading-out the state of the storage register.
  • the storage register of digital voltmer 34 is associated with a rate multiplier which constitutes first digital means 29.
  • a rate multiplier is a conventional digital device that effectively multiplies an applied pulse train by a number.
  • a rate multiplier is a pulse train distributor which is effective to distribute various fractions of the input pulses into different lines each of which is ANDed with a different level signal derived from an associated cell of a storage register which holds the multiplier.
  • the output of the rate multiplier is derived from all of the outputs of the AND gates. Only a gate whose association cell furnishes an assertion level will pass the fraction of the input pulses by thereto, with the result that the total fraction of input pulses pass by the rate multiplier will depend upon which cells of the storage register provide assertion levels.
  • One-half of the input pulses (e.g., four of each group of eight input pulses) will be sent along a first output line; one-fourth of the input pulses (e.g., two out of each group of eight input pulses) will be sent along a second output line; and one-eighth of the input pulses (e.g., one out of each group of eight input pulses) will be sent along a third output line.
  • Each of these output lines is ANDed with a level derived from a three cell storage register whose contents represents the multiplier.
  • the multiplier would be one-half, and the output of the rate multiplier would be pulses coincident in time with the first, third, fifth and seventh pulses of each group of eight input pulses. If there were an assertion level present only at the AND gate associated with the second line of the pulse distributor, the multiplier would be one-fourth, and the output of the rate multiplier would be pulses coincident in time with the second and sixth pulse of each group of eight input pulses.
  • the multiplier would be three-fourths, and the output of the rate multiplier would be pulses coincident in time with the first, second, third, fifth, sixth, and seventh pulse of each group of eight input pulses.
  • An assertion level present at each AND gate corresponds to a multiplier of seven-eights, and would permit the rate multiplier to pass pulses coincident in time with the first seven of each group of eight input pulses.
  • the number of cells of the rate multiplier determines the size of the group of input pulses that establishes the basis for distribution, and that the time period required for this group of pulses to be received by the multiplier determines a reference period of time. Within such period of time, from one through a number equal of one less than the total number of pulses in a group can be passed by the multiplier, depending on the contents of the storage register. As a consequence, the average frequency of the output pulses of a rate multiplier, namely the number of output pulses per reference period of time, depends on the contents of the storage register.
  • Rate multipliers are not limited to binary counters, and are available for binary-coded-decimal (BCD) counters, for example.
  • BCD binary-coded-decimal
  • a four cell counter is provided for each decimal place, and is arranged to count from 0 to 9 rather than to 15.
  • a BCD rate multiplier could pass between one and nine pulses in each group of ten input pulses, depending on the contents of a four cell storage register. If an eight cell counter were involved to provide two decimal places, from one through 99 pulses in each group of one hundred pulses could be passed by the multiplier.
  • the present invention contemplates using a standard digital voltmeter as a storage register for rate multiplier 29. Voltmeters conventionally used BCD readout; and for this reason rate multiplier 29 is a BCD rate multiplier. However, other types of analog-to-digital converters could be used to convert the analog signal produced by cell 33 to a digital signal. In such case, the rate multiplier would be selected to be compatible with the converter.
  • the output of encoder 28 which is a pulse train whose number of pulses per unit time is representative of the instantaneous belt speed, is applied to the pulse input of multiplier 29.
  • the storage registers of voltmeter 34 whose contents are representative of the instantaneous mass of the material on the belt, are applied to the level input terminals of multiplier 29.
  • the output of rate multiplier 29 is a train of feedback pulses whose number per unit time is representative of the actual instantaneous mass flow rate of material on the belt.
  • a train of pulses is applied to the pulse input terminal 54 of rate multiplier 36 through switch 56.
  • the pulses may be produced by a crystal oscillator or clock 58.
  • pulses may be applied to the pulse input terminal 54 of rate multiplier 36 through input terminal 60 and switch 56.
  • the output of a variable frequency source (not shown) is applied to input terminal 60 with switch 56 in the ratio position, the output of rate multiplier 36 will be equal to that frequency input times the decimal fraction set on thumbwheel switch register 40.
  • variable frequency source may be the output obtained from rate multiplier 29 of another similar conveyor thereby permitting slaving of one unit to another.
  • the digital mass flow control system of a conveyor may be slaved to any suitable device such as a turbine flow meter which produces a suitable pulse signal.
  • Rate multiplier 36 is of the same type as rate multiplier 29.
  • the level input terminals of rate multiplier 36 are connected with thumbwheel-switch register 40 which permits assertion levels to be selectively applied to each of the gates of the pulse distributor of multiplier 36.
  • a manual setting of the contents of the thumbwheel-switch register determines the multiplier term by which the clock pulses are to be multiplied.
  • the output of multiplier 36 is thus a train of setpoint pulses whose number per unit time is representative of the desired instantaneous mass flow.
  • the pulse trains from rate multipliers 29 and 36 are applied through synch means 37 and gate means 38 to second digital means 31 constituted by an up/down digital counter.
  • the setpoint pulse train from rate multiplier 36 is applied to "up" terminal 41 while the feedback pulse train derived from multiplier 29 is applied to the "down" terminal 42 of the counter.
  • the pulses representative of the desired instantaneous mass flow rate will cause counter 31 to count upwardly, while pulses representative of the actual instantaneous mass flow rate will cause counter 31 to count downwardly.
  • the state of counter 31 will be stable. In such case, the actual mass flow rate of material on the belt will be the desired setpoint rate.
  • Control means 32 in the form of a current-output type servoamplifier, converts the contents of counter 31 to an analog signal the level of which determines the amount of armature current furnished to motor 23.
  • the output lines 43 associated with the cells of counter 31 may have the usual binary weights: 1, 2, 4, 8, etc. These lines are associated with similarly weighted control circuit in servoamplifier 32. The level of output current from servoamplifier 32 will thus depend upon which of the output lines 43 of counter 31 are asserted.
  • System 26 effects the necessary decrease in motor speed as follows. As the mass of the material on belt 19 increases, there will be an increase in the level of the signal produced by load cell 33 with result that the contents of the storage register of voltmeter 34 will increase. This will effectively increase the value of the term by which the pulses produced by encoder 28 are multiplied in multiplier 29. The average frequency of the output of multiplier 29 will thus increase causing counter 31 to begin to count downwardly.
  • synch circuit 37 is utilized. This is a conventional circuit which will synchronize the setpoint pulses produced by multiplier 36 and feedback pulses produced by multiplier 29 with alternate half cycles of a clock frequency higher than the maximum setpoint or feedback rate. In this manner, correct counting will be achieved even if setpoint and feedback pulses should occur simultaneously.
  • counter 31 When system 26 is unable to provide sufficient corrective action to restore the actual mass flow rate to the setpoint value, counter 31 will continuously count either upwardly or downwardly depending upon the corrective action required. Eventually, the counter would either "overflow” and change from its highest state to its lowest state, or would “underflow” and change from its lowest state to its highest state causing a serious discontinuity in the operation of amplifier 32 and motor 23. To preclude the occurrance of these events, decoding circuits 44 and 45 are employed in connection with output lines 43 of counter 31. Decoding circuit 44 will detect the maximum counter output and produce a control signal at inhibit gate 46 of gate means 38 preventing passage of additional setpoint pulses from multiplier 36 which would normally cause counter 31 to count upwardly and result in an "overflow" situation.
  • decoding circuit 45 will detect the minimum counter output and produce a control signal at inhibit gate 47 blocking additional feedback pulses from multiplier 29 that would normally cause counter 31 to count downwardly and result in an "underflow" situation.
  • the signals derived from decoding circuits 44 and 45 may also be used to initiate an alarm or cause the motor to be shut down.
  • the servoamplifier may be biased so that current flow to the motor armature will begin at some counter value greater than one. This will provide a memory capacity of several counts should the motor armature turn rapidly after overcoming static friction and cause several extra feedback pulses to be applied to the "down" terminal 42 of the counter. Because of these remembered pulses, the motor will not start again until the extra pulses have been offset by incoming setpoint pulses applied to "up" terminal 41.
  • counter 31 may be provided with five binary stages thereby having 32 possible states or counts. Gating means, not shown, may be provided to gate the upper 16 counts of the five stage binary counter to serve as the input to servo amplifier 32. The lower 16 counts of the five stage binary counter may serve as a memory reserve for conditions where the feedback pulses have exceeded setpoint pulses.
  • This digital arrangement may be used as an alternative to biasing servo amplifier 32 as described above. However, it is to be understood that the description in terms of counter 31 being a four or five stage binary counter is not intended to be limiting. Counter 31 in the digital arrangement may be larger or smaller than a five bit counter.
  • counter 31 may be a six bit binary counter in which the upper 32 or some other suitable number of counts are gated to serve as the input to servo amplifier 32 and the remaining lower counts serve as a memory.
  • memory may also be provided at the upper end of the counter range for conditions where motor 23 may not be able to immediately follow a rapidly increasing setpoint due to physical limitations. Under conditions where motor 23 is not able to perfectly track a rapidly increasing setpoint, means would be provided to hold the gates to the input of servo amplifier 32 in an enabled condition.
  • Encoder 28 is a conventional device for converting shaft rotation into a digital signal. As seen in FIG. 2, encoder 28 includes a coded disc 48 attached to the shaft upon which belt pulley 21 is mounted. Optical device 49 of the encoder views disc 48 as it rotates in response to belt movement causing a pulsed signal to appear at output lead 50. This pulsed signal will ave a frequency directly related to the belt speed. While an optical encoder is disclosed, it will be obvious to persons skilled in the art that other types of encoders could also be employed such as a proximity type magnetic pickup with a gear made of a magnetic material.
  • each pulse appearing at the output of multiplier 29 represents a discrete increment of mass passed by the belt.
  • the total mass of material passed by the conveyor can therefore be accumulated by scaling and counting the output of multiplier 29.
  • scaling means 51 divides the pulses produced by multiplier 29 by a predetermined value and provides output pulses accumulated in counter 52. The contents of counter 52 will represent the total mass of material passed by the conveyor belt 19.
  • counter 52 is a bi-directional counter.
  • Counter 52 receives a countup or a countdown signal via line 62 from digital voltmeter 34.
  • Digital voltmeter 34 may be provided with means 64 which provides a tare control.
  • Means 64 may be a zero adjust on commercially available digital voltmeters. Means 64 allows adjustment to produce a zero output level from digital voltmeter 34 for a predetermined input from load cell 33. In order to accurately tare a conveyor belt system it is desirable to have the counter 52 with a readout which is bi-directional in operation.
  • counter 52 does not show a significant net change of reading with an empty conveyor belt despite minor positive and negative excursions caused by variations in the geometry and composition of the conveyor belt.
  • This bi-directional operation of counter 52 is accomplished by providing a polarity output signal on line 62 from digital voltmeter 34 as aforesaid.
  • a switch 66 is provided to by-pass scaling means 51 in order to provide greater sensitivity during the taring operation of the conveyor belt.
  • Switch 25 permits by-passing of rate multiplier 29 when in the volumetric position.
  • Switch 25 in the volumetric position allows the direct feedback of pulses from encoder 28 to up/down counter 31 through synch means 37 and gate means 38. This allows direct control of the conveyor belt speed as contrasted with mass flow or gravity control which is a function of conveyor belt speed and conveyor belt loading. Operation in the volumetric mode may be advantageously used for taring the conveyor belt and for emergency operation as a volumetric (as opposed to a gravimetric) feeder in emergencies such as failure of the load cell 33.
  • a mass flow rate readout is provided by counter 68, storage register 70 and numeric display 72.
  • the output of rate multiplier 29 as described above is a pulse train having a frequency representative of the mass flow on the conveyor belt 14.
  • Counter 68 os provided with timing means which allows it to count for a predetermined period of time. At the end of each predetermined period of time, the contents of counter 68 is transferred to storage register 70. The count stored in storage register 70 is displayed by numeric display 72 providing a visual readout. By suitable selection of the predetermined period of time during which counter 68 counts, numeric display 72 will read directly in engineering units which may be, for example, pounds per hour.
  • encoder 28, weighing means 27, rate multiplier 29, scaling means 51, counters 52 and 68, storage register 70 and numeric display 72 may be operated independently of the remainder of the system as a total mass flow indicator and a mass flow rate indicator.
  • N includes an integer greater than zero. .Iaddend.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Automation & Control Theory (AREA)
  • Mechanical Engineering (AREA)
  • Control Of Conveyors (AREA)
US05/564,965 1971-08-05 1975-04-03 Digital mass flow control system Expired - Lifetime USRE30684E (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US05/564,965 USRE30684E (en) 1971-08-05 1975-04-03 Digital mass flow control system

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US16939871A 1971-08-05 1971-08-05
US05/564,965 USRE30684E (en) 1971-08-05 1975-04-03 Digital mass flow control system

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
US16939871A Reissue 1971-08-05 1971-08-05

Publications (2)

Publication Number Publication Date
USRE30684E true USRE30684E (en) 1981-07-21
USRE30684F1 USRE30684F1 (enrdf_load_stackoverflow) 1983-05-03

Family

ID=26865016

Family Applications (1)

Application Number Title Priority Date Filing Date
US05/564,965 Expired - Lifetime USRE30684E (en) 1971-08-05 1975-04-03 Digital mass flow control system

Country Status (1)

Country Link
US (1) USRE30684E (enrdf_load_stackoverflow)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4386302A (en) 1979-11-12 1983-05-31 Olympus Optical Co., Ltd. Control device for a multispeed motor
US20090321664A1 (en) * 2006-09-25 2009-12-31 Basf Se Method for the Continuous Production of Water-Absorbent Polymer Particles
US20140327383A1 (en) * 2013-05-06 2014-11-06 Raf Technology, Inc. Parcel and mass flow scale
US9863801B2 (en) 2014-05-01 2018-01-09 Velox Robotics, Llc High speed robotic weighing system

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3110853A (en) * 1958-06-05 1963-11-12 Westinghouse Electric Corp Electrical control apparatus
US3176208A (en) * 1962-07-02 1965-03-30 North American Aviation Inc Phase locking control device
US3278747A (en) * 1963-07-29 1966-10-11 Ohmart Corp Method and apparatus for continuously weighing material on a conveyor comprising a radioactive source and detector
US3303967A (en) * 1965-09-28 1967-02-14 Westinghouse Electric Corp Feedback control for a material handling system providing automatic overshoot correction
US3407656A (en) * 1966-03-17 1968-10-29 Alsthom Cgee Apparatus for continuous weighing of powdered or granular materials with weight regulation of the flow
US3412699A (en) * 1966-03-22 1968-11-26 Babcock & Wilcox Co Fuel feeding apparatus
US3494507A (en) * 1966-07-05 1970-02-10 Ronald J Ricciardi Metering apparatus
US3543116A (en) * 1968-05-01 1970-11-24 Avtron Mfg Inc Digital variable speed controller comparing a tachometer pulse source with a reference

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3110853A (en) * 1958-06-05 1963-11-12 Westinghouse Electric Corp Electrical control apparatus
US3176208A (en) * 1962-07-02 1965-03-30 North American Aviation Inc Phase locking control device
US3278747A (en) * 1963-07-29 1966-10-11 Ohmart Corp Method and apparatus for continuously weighing material on a conveyor comprising a radioactive source and detector
US3303967A (en) * 1965-09-28 1967-02-14 Westinghouse Electric Corp Feedback control for a material handling system providing automatic overshoot correction
US3407656A (en) * 1966-03-17 1968-10-29 Alsthom Cgee Apparatus for continuous weighing of powdered or granular materials with weight regulation of the flow
US3412699A (en) * 1966-03-22 1968-11-26 Babcock & Wilcox Co Fuel feeding apparatus
US3494507A (en) * 1966-07-05 1970-02-10 Ronald J Ricciardi Metering apparatus
US3543116A (en) * 1968-05-01 1970-11-24 Avtron Mfg Inc Digital variable speed controller comparing a tachometer pulse source with a reference

Non-Patent Citations (20)

* Cited by examiner, † Cited by third party
Title
98-100 Series Ratio Set Module, 19-410 Aug. 1969, Foxboro Co. *
98-100 Series Ratio Set Module, Foxboro Co., GS7-7A2A-F, Sep. 1965. *
98-200 Standardized Module, 19-420, 2/70, Foxboro Co. *
98-300 Series Automatic Pacing Digital Controller, 19-430, Jul. 1969, Foxboro Co., pp. 1-8. *
98-400 Digital Controller with Memory, 19-440, Foxboro Co., 7/69. *
98-500 Series Master Demand Module 19-450, Jul. 1969, Foxboro Co., 11/70. *
Control Systems for Belt Feeders, Instrumentation Technology, L. D. McEvoy, Feb. 1968, pp. 41-45. *
Drawing, Merrick Scale Co., Sketch 252, 7-24-63. *
Electronic Digital Techniques, Paul Kitner, McGraw Hill Book Co., pp. 258-268, 1968. *
Foxboro Catalogue, Bulletin 570, p. A54-A64. *
Mineral Processing, Apr. 1965, pp. 19-22, Title Digital vs. Analog Proportional Feed Control. *
One Kiln, Two Mills, Minerals Processing, May 1966, pp. 16-19. *
Proportioning Systems for Food Industry, Reynold Zanetti, Merrick Scale Mfg. Co., Oct. 1970. *
Proportioning Systems, Merrick Scale Mfg. Co. Application Data Sheet ADS1041, 3/69, pp. 3-12. *
Tech Information Bulletin 16-54a, Foxboro Co., Foxboro, Mass., Aug. 30, 1965, pp. 1-6. *
Technical Information 16-51a, Foxboro Co., Aug. 30, 1965. *
Technical Information 16-53a, Foxboro Co., Aug. 30, 1965, pp. 1-5. *
Technical Information 16-55a, Foxboro Co., Aug. 30, 1965, pp. 1-4. *
Total Capability, Foxboro, pp. 2-11, L-15A. *
Weightometer, Merrick Co., Specification Sheet 331, 12/68. *

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4386302A (en) 1979-11-12 1983-05-31 Olympus Optical Co., Ltd. Control device for a multispeed motor
US20090321664A1 (en) * 2006-09-25 2009-12-31 Basf Se Method for the Continuous Production of Water-Absorbent Polymer Particles
US8610097B2 (en) * 2006-09-25 2013-12-17 Basf Se Method for the continuous production of water-absorbent polymer particles
US20140327383A1 (en) * 2013-05-06 2014-11-06 Raf Technology, Inc. Parcel and mass flow scale
US9564849B2 (en) * 2013-05-06 2017-02-07 Raf Technology, Inc. Scale for weighing flowing granular materials
US9857214B2 (en) 2013-05-06 2018-01-02 Velox Robotics, Llc Scale for weighing parcels
US9863801B2 (en) 2014-05-01 2018-01-09 Velox Robotics, Llc High speed robotic weighing system

Also Published As

Publication number Publication date
USRE30684F1 (enrdf_load_stackoverflow) 1983-05-03

Similar Documents

Publication Publication Date Title
US3724720A (en) Digital mass flow control system
CA1048557A (en) Apparatus for controlling the feed rate and batch size of a material feeder
US4054784A (en) Weigh feeder system
GB1584886A (en) Weigh feeding machine
US4301510A (en) Weigh feeder system
USRE32102E (en) Weigh feeding apparatus
GB1427774A (en) Metering device for flowable materials
US3679010A (en) Digitally controlled mass flow feeder and weight integrator
CA1297588C (en) Measurement of flow rate of power from a hopper
US3754126A (en) Integrating conveyor scale
USRE30684E (en) Digital mass flow control system
US3610908A (en) Electronic integrator system
US3802522A (en) Batch weighing system
GB1429679A (en) Method for metering commodities with respect to weight
US3960225A (en) Conveyor belt system with positional transformation of weight data
DE2149300A1 (de) Geraet zur Ermittlung der Auswuchtwerte eines Fahrzeugrades
US4257261A (en) Method and apparatus for controlling load of dynamometer
FR2440576A1 (fr) Doseur ponderal de matieres granuleuses ou pulverulentes
CA1196997A (en) Apparatus for controlling the speed of a rotating body
US3778035A (en) Moisture compensating system
US3202317A (en) Detection and control system
US3405842A (en) Gravimetric belt feeder
JPS5722517A (en) Device for measuring flow rate of granular material
US3139578A (en) Continuous automatic ore assay system
SU670816A1 (ru) Дозатор сыпучих материалов

Legal Events

Date Code Title Description
AS Assignment

Owner name: K-TRON TECHNOLOGIES, INC., DELAWARE TRUST BLDG., 9

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:K-TRON INTERNATIONAL, INC., A CORP. OF NJ;REEL/FRAME:005556/0338

Effective date: 19901227