US3194546A - Mechanism and method for controlling sintering - Google Patents

Mechanism and method for controlling sintering Download PDF

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Publication number
US3194546A
US3194546A US758106A US75810658A US3194546A US 3194546 A US3194546 A US 3194546A US 758106 A US758106 A US 758106A US 75810658 A US75810658 A US 75810658A US 3194546 A US3194546 A US 3194546A
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Prior art keywords
grate
relay
burn
feed rate
operatively connected
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US758106A
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Thomas R Schuerger
Frank Slamar
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United States Steel Corp
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United States Steel Corp
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Priority to US758106A priority Critical patent/US3194546A/en
Priority to GB27924/59A priority patent/GB906394A/en
Priority to BE581992A priority patent/BE581992A/fr
Priority to FR803729A priority patent/FR1249834A/fr
Priority to DEU6460A priority patent/DE1142619B/de
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    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D11/00—Control of flow ratio
    • G05D11/02—Controlling ratio of two or more flows of fluid or fluent material
    • G05D11/13—Controlling ratio of two or more flows of fluid or fluent material characterised by the use of electric means
    • G05D11/135—Controlling ratio of two or more flows of fluid or fluent material characterised by the use of electric means by sensing at least one property of the mixture
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B1/00—Preliminary treatment of ores or scrap
    • C22B1/14—Agglomerating; Briquetting; Binding; Granulating
    • C22B1/16—Sintering; Agglomerating
    • C22B1/20—Sintering; Agglomerating in sintering machines with movable grates
    • C22B1/205—Sintering; Agglomerating in sintering machines with movable grates regulation of the sintering process
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D5/00—Control of dimensions of material
    • G05D5/02—Control of dimensions of material of thickness, e.g. of rolled material
    • G05D5/03—Control of dimensions of material of thickness, e.g. of rolled material characterised by the use of electric means

Definitions

  • This invention relates to an improved mechanism and method for controlling la sintering operation.
  • a carefully proportioned combustible mix of metal-bearing particles for example iron ore
  • fuel and water feeds to the grate adjacent its entry end.
  • the upper surface of the resulting bed is ignited shortly beyond the line of feeding. Air is drawn or forced downwardly through the bed, and combustion proceeds in a thin zone which slopes downwardly from the line of ignition to a line along the grate, known as the burn-through point.
  • the burn-through point For eflicient operation the location of the burn-through point must be carefully controlled. If the burn-through point lies too near the discharge end of the grate, the finished sinter contains unburned fuel and is of poor quality.
  • the location of the burn-through point is a function of grate speed, the rate at which the material burns, and the rate at which material feeds to the grate.
  • a compounding apparatus which includes a main conveyor belt, a series of bins located above the belt and containing the individual ingredients, and table feeders for feeding these ingredients in controlled quantities to the belt.
  • bins farthest from the discharge end of the belt usually contain ore fines and equivalents.
  • the next bins usually contain fuel (for example coke and anthracite nes) and other additives.
  • the bin nearest the discharge end usually contains hot fines returned from the sintering machine for recycling.
  • hot recycle are another equivalent of ore and must be used approximately as received, except that the bin allows suicient surge capacity to permit their feeding at uniform rates for extended periods.
  • the present invention concerns a control mechanism and method in which the weight of material fed to the grate is adjusted automatically to hold the burn-through point at any set location.
  • the grate speed adjusts itself automatically to maintain the depth of bed on the grate within a predetermined range despite varying feed rates.
  • the setting can be changed, Whereupon both the feed rate land grate speed automatically change accordingly.
  • This invention makes use of a burnthrough indicator on the sintering machine and controls on the feed compounding apparatus similar to those shown in the foregoing applications, plus suitable computing circuits, whereby the burn-through location directly controls the sum of the rates at which ore and hot recycle feed in the compounding apparatus.
  • An object of the present invention is to provide fully automatic control of a sintering operation, whereby both the rate at which material feeds to a sintering machine and the grate speed adjust themselves automatically to values that hold the burn-through point at any desired location and maintain the depth of bed on the grate within a predetermined range.
  • a further object is to provide an improved mechanism and method for controlling a sintering operation in which the only manual adjustments are in setting the location of the burn-through point on the grate and in setting the proportions of additives and water, all other variables being automatically controlled for optimum eiciency in accordance with the setting of the burn-through location.
  • a further object is to provide an improved mechanism and method in which the controls shown in the aforesaid applications are combined to afford completely automated control of a sintering operation.
  • a more specific object is to provide an improved control mechanism and method for a sintering operation in which a burn-through indicator on a sintering machine is connected through a suitable feed rate computing circuit with an ore feed control on a feed compounding apparatus, whereby the circuit automatically regulates the weight of sinter feed produced and fed to the sintering machine to hold the burn-through point at a set location, and in which the grate speed is automatically regulated to maintain the depth of bed on the grate Within a predetermined range.
  • FIGURE 1 is a diagrammatic side elevational view of a sintering installation equipped with control mechanism in accordance with our invention
  • FIGURE 2 is a schematic showing of our feed rate computing circuit, the timer circuit being omitted to simplify the illustration;
  • FIG. 3 is a schematic Wiring diagram of the timer y, 3 circuit for the computing circuit shown in FIGURE 2;
  • FIGURE 4 is a graph showing the sequence of operation
  • FIGURE 5 is-a schematic showing of our grate speed control mechanism.
  • FIGURE 1 shows diagrammatically a sintering installation which includes a feed compounding apparatus 10, a mixer 12, and a traveling grate sintering machine 13, all conventional apart from our control mechanism.
  • the compounding apparatus comprises a suitably driven main conveyor belt 14, a plurality of ore bins 15, two trimmer ore bins 16, two additive bins 1'7, ⁇ and a hot recycle bin 18.
  • the bins 15, 16, 17 and 13 are equipped with table feeders 19, 20, 21 and 22 respectively which have variable speed D.-C. drive motors 23,. 24, 25 and 26.
  • the respective ingredients feed from the bins to the belt in quantities individually controlled by regulating the speeds of theY table feeder motors.
  • the sintering rnachine comprises a traveling grate 29, a variable speed D.C. motor 31 for driving the grate, and an ignition device 32.
  • Motor 31 is equipped with a speed control mechanism 33 actuated by low and high level sensing means 34 and 35 mounted adjacent the feed end of the grate.
  • the control mechanism 33 hereinafter fully described, automatically maintains the grate speed at a value such that the bed depth remains within a range defined by the two sensing means regardless of the feed rate.
  • the sintering machine also includes the usual windboXes, blowers, and otherconventional parts, but they are not shown since they are not involved in the present invention.
  • the feed compounding apparatus is equipped with controls essentially like those shown in Schuergerapplication Serial No. 579,326, except we have added an automatic control mechanism 36 for motor 26 which drives the hot recycle feeder 22, an automatic control mechanism 37 formotors 24 which drive the trimmer ore bin feeders 2t), and a reset mechanism 38 for motors 23 which drive the feeders 19 from the other ore bins.
  • the control mechanism 36 is like that shown in our application Serial No. 739,870, and the mechanisms y37 and 38 like those shown tin our application Serial No. 746,261.
  • the sintering machine is equipped with a burn-through indicator 39 like that shown in the Dykeman and Schuerger application.
  • the rate at which ore feeds to belt 14 from bins 15 and 16 is controlled through three signals proportionate to (a) the desired sum of the ore and hot recycle feed rates,
  • the ore feed rate is regulated to maintain the sum of the ore feed rate and the hot recycle setting at a value determined by signalA (a). The sum remains constant between successive computations of this signal. Any change in signals (a) or (c) necessitates .a change in the ore feed rate. As long as only routineadjustments .are
  • the ⁇ control mechanism 37 The belt discharges the asp continuously regulates the speed of motors 24 yand hence changes only the rate at which ore feeds from the trimmer bins ⁇ 16.
  • NormallyV motors 23 run at constant speed, whereby ore feeds at a constant rate from the other bins i 15.v
  • the control mechanism 37 actuates the reset mechanism 38. Thereupon the reset mechanism periodically changes the speed of motors 23 until the feed rate from bins 15 reaches a value at ⁇ which the trimmer bins alone can handle necessary adjustments intheV total ore feed rate. Occasionally the weight of ore reaching belt 14 may change even though the speed of the feeder motors 23 and 24 does,not'change. The resulting change in signal (b) immediately corrects the speed of motors 24 accordingly.
  • the hot recycle control mechanism 36 computesa new speed for motor 26, which drives the feeder 22 on the hot recycle bin 18. If the level of hot recycle 1in the bin is within a predetermined range, the new speed equals the instant speed, or the linstant speed with a temporary increment discontinued. 1f the level is outside the range, the new speed equals the ⁇ algebraic sum of the instant speed, a temporary increment (positive or negative) to return the level to the predetermined range, and a permanent increment (positive or negative) to hold the level within this range after it has returned.
  • Signal (c) is representative of the computed new speed.
  • the control mechanism 37 immediately changes the ore feed rate linversely to the change indicated lin the hot recycle feed rate, and thus maintains the sum at the value Vdetermined by signal (a). After a delay sufficient for belt 14 to carry the changed quantity of ore oppositethe hot recycle bin 13, the computed new speed is applied tormotor 26. Belt 14 runs over conventional belt scales 42 and 43 immediately before and after hot recycle feeds thereto.
  • This summat-or transmits a signal vproportionate to said :total to ratio devices 49, which regulate the Spee-d of motors 25 :driving the additive feeders V21, and to another natio device 50, which regulates ⁇ a valve 51 in the water line 27.
  • ratio devices 49 which regulate the Spee-d of motors 25 :driving the additive feeders V21, and to another natio device 50, which regulates ⁇ a valve 51 in the water line 27.
  • These ratio devices are individually adjustable, whereby additives and water can be included in any desired ratio with respect to the sum of the ore land hot recycle.
  • the Schuerger application cites speci-tic examples of known instruments suitable as sure signal through a suitable transducer, such as that shown in a printed publication by the Foxboro Company, Foxboro, Massachuetts, Bulletin 20-16 entitled E.M.F. Pneumatic Transmitter.
  • Feed rate computing circuit FIGURE 2 shows the t'eed rate computing circuit 40 in more detail, apart from its timer circuit shown separately in IF ⁇ IGURU'1 ⁇ J 3.
  • the circuit 40 acts in conjunction with the burn-through indicator 39 to determine whether .the burn-through point actually is at the location .to which it has been set, yand if not, to compute -a new feed rate to shift burn-through point tothe set location. If the burn-through point lies too far from the discharge end of the grate, the feed rate is increased; if it lies ltoo near the discharge end, the feed rate is decreased.
  • the circuit 40 exercises direct control only Iover the su-m of the ore and hot recycle feed rat-e, but this sum is representative of the total feed rate, since the additives are proportioned :directly in accordance therewith.
  • the b-urn-through indicator 39 includes a servomotor (designated 30 in the Dyketman and Schuerger :application) which is mechanically connected to the arm 52 of a potentiometer 53.
  • the indicator 39 positions this arm ⁇ along the potentiometer slide Wire in accordance with the actual distance L between the ignition point :and the burn-through point.
  • a manually .adjustable set-point -indicator 54 is mechanically connected to the varm 55 of another potentiometer 56 to position this arm along the potentiometer slide Wire in accordance with Ithe set distance L between the same ignition point and the burnthrough point.
  • the respective slide wires are connected to .suitable D.C. voltage sources, whereby arms 52 and -55 transmit voltages proportionate to Land L0 respectively.
  • Arms 52 and 55 are :electrically connected to a divider 57, which computes -any variance between the actual and set locations of the burn-through point las Ia ratio LO/L.
  • the divider includes .an electronic conversion amplifier 58, :a servomotor 59 and a potentiometer 60 whose arm 61 is mechanically connected to the servomotor.
  • Arm ⁇ 55 is electrically connected to one input terminal of the amplier, whereby the voltage applied to this terminal is proportionate to L0.
  • Arm 52 is electrically connected to one end of :the slide Wire of potentiometer l, .an-d ⁇ arm 61 of the latter .potentiometer is electrically connected to the other input terminal of the amplifier.
  • the voltage applied to the 'latter terminal is proportionate to L multiplied by a fraction whose value depends on the linear position of arm .61 with respect to its slide wire.
  • Amplifier ⁇ 58 .and servomotor 59 are electrically connected to a suitable A.C. source 62.
  • the output terminals of ampliier S are 'electrically connected to a field winding 63 of the serv-omotor.
  • Amplifier 58 has the characteristic that it energizes the serv-omotor in the appropriate direction Whenever its two input terminals .are yat different voltages. When the servornotor runs, it moves arm 61 .along its slide wire in a direction to equalize the voltages applied lto the input terminals.
  • the Vamplifier 58 per se is ta known device and hence has been shown only in block form, but reference can be made to Wills Patent No. 2,423,540 for a complete showing of :a suitable amplifier of this type.
  • a suitable arnplier is available commercially from Minneapolis- Honeywell Regulator Company runder the tradename Electronik, No. 356,358, and is described in a printed publication by the manufacturer entitled Service Manual 6 SO M for Class 15 Electronik Instruments IIssue 8 .
  • the servomotor 59 of the divider 57 also is mechanically connected ⁇ to the arm 64 of a potentiometer 65.
  • the slide Wire of this potentiometer is connected to a D.-C.
  • Arm o4 assumes a position in accordance with the ratio Lo/L, whereby it transmits la voltage proportionate to the product FLO/L.
  • the corrected feed rate F0 would equal this product, since the corrected .rate F0 bears the same ratio to the actual rate iF as the set distance L0 between .the ignition point and ythe burn-through point bears to the actual distance L, that is However, we preferably apply the Voltage transmitted by arm 64 to an integrator 66 for the purpose of computing an average value of FLO/L over a definite time interval and thus eliminating effects of minor fluctuations or noise in the measured distance L.
  • the integrator includes an electronic conversion ampliher 67 (similar to amplifier 58), a servomotor 68, and a tachometer-generator 69 mechanically connected to the servomotor.
  • the servomotor is a two-phase A.-C. induction motor which has the characteristic that under transient conditions its speed varies with the voltage applied to its iield. We have not described the motor in detail since it is a known device, but for a complete description reference can be made to Thaler and Brown Servo-Mechanisms Analysis, copyright 1953 by McGraw-Hill Book Company, Inc., pages 63 and 391.
  • One input terminal of ampliier 67 is electrically connected to arm 64 of potentiometer 65, whereby the voltage applied to this terminal is proportionate to FLO/L, but subject to fluctuations.
  • the other input terminal of the ampliiier is electrically connected to the generator 69, whereby the voltage applied to the latter terminal is proportionate to the output of the generator.
  • the voltages applied to the two input terminals are of the same polarity, but the latter is smaller.
  • Ampliiier 67 and servcmotor 63 are electrically connected to a suitable A.C. source 70.
  • the output terminals of amplier 67 are electrically connected to a iield winding 71 of servomotor 68.
  • Front contacts A2 of relay A are connected in series with servornotor 68, and are closed automatically by the timer circuit for a definite interval,
  • the integrator o6 is not a null-seeking device like the divider 57, but voltages applied to its two amplifier input terminals approach values which differ by an amount proportionate to the voltage to be integrated.
  • the amplifier 67 allows the servomotor 63 to run as long as contacts A2 remain closed.
  • e2 represent the input voltage to the amplifier derived from the tachometer-generator
  • t represent the time interval the servomotor runs for each computation
  • x represents the number of revolutions of the tachometergenerator during time t.
  • (e2-e1) is the eitective voltage which tends to drive the servomotor
  • lx/dt is the angular velocity of the tachometer-generator.
  • x is a function of e1
  • measurement of x over a definite time interval can be used to obtain a measurement of an average value of el or FLO/L for the same interval.
  • the tachometerugenerator 69 is mechanically connected to the arm 7270i a potentiometer 73 through suitable reduction gearing. Consequently the distance which the arm travels during time interval t furnishes a measure of the number of revolutions x during this interval.
  • the slide wire of potentiometer 73 is electrically connected to a suitable D.C. voltage source, whereby arm 72, transmits a voltage proportionate to thecomputed average value of FLO/L during the interval t. This value is taken as F0, the corrected feed rate.
  • the potentiometer arm 72 is reset to its zero position.
  • the connection between arm 64 and the first input terminal of amplifier 6 ⁇ ? contains a contact B1 of a relay B and the connection between the generator 69 and the other input terminal of the amplier contains a contact B2 of relay B, which contacts are closed while the integrator is performing a computation.
  • a contact B3 of relay B is adapted to connect the irst input vterminal to a ground '74.
  • a contact B., of relay B is .adapted to connect the other input terminal to arm 72 of potentiometer '73.
  • Additional contacts B5 of relay B are adapted to connect servomotor 68 to the A.C. source 7GB, bypassing contacts A2.
  • Contacts B3, B and B5 are open while the integrator is performing a computation.
  • Relay B itself is part of the timer circuit hereinafter described.
  • contacts B1 and B2 open and contacts B3, B4 and B5 close.
  • the servomotor V58 runs in the reverse direction until the voltages applied to the two input terminals of the amplifier 67 are equal. Since one terminal is grounded at 74, these voltages become equal when the other terminal is grounded, that is, when the potentiometer arm 72 reaches its zero setting.
  • the integrator in effect becomes a null-seeking device while it is resetting the arm.
  • the memory device includes ⁇ an electronic conversion amplier 76 (similar to amplifiers 58 and o7), a servomotor 77, and a potentiometer 78 whose arm 79 is mechanically connected to the servomotor.
  • the slide wire of potentiometer 78 is electrically connected to a suitable D.C. source.
  • Arm '72 is electrically connected to one input terminal of amplifier 76, whereby the voltage applied to this terminal is proportionate to F0.
  • Arm 79 is electrically connected to the -other input terminal of the ampliiier, whereby the voltage applied to this terminal equals that applied to the slide wire of potentiometer 78 multiplied by a fraction whose value depends on the linear position of arm 79 with respect to the slide wire.
  • ⁇ Amplifier 76 and servomotor 77 are electrically connected to a suitable A.C. source 80.
  • the output terminals of amplifier 76 are electrically connected to a field winding 81 of the servomotor.
  • the action of the memory device is similar to that of the divider 57; that is, the servomotor 77 stops after moving arm 79 to a linear position along its slide wire representative of the computed value
  • Front contacts C1 of a relay C are connected in the A.C. circuit S0.
  • the relay itself is part of the timer circuit hereinafter described.
  • Y Contacts C1 automatically close long enough to enable the servomotor 77 of theV memory device to set theY potentiometer arm 79 to the new value of F0 computed by the integrator. Thereafter these contacts reopen to hold the arm ⁇ at this setting until another new setting is computed.
  • Theservometer 77 of the memory device 75 also is mechanically connected to the arm 82 of a potentiometer 83, which is electrically connected to a suitable D.C. source. Arm S2 thus assumes a position in accordance with the computed value of F0, and transmits a'proportionate Voltage. Arm 82 is electrically connected to the trimmer bin control mechanism and transmits signal (a) thereto. As already explained the total feed rate bears a known ratio to the sum of the ore and hot recycle feed rates; hence the computed value of Fo also is representative of this sum.
  • the potentiometer arm 82 also is electrically connected to the slide wire of potentiometer 65 and transmits a voltage thereto to be'used as For the instant feed rate in the next computaion.
  • Circuit to thev servomotor 77 of the memory device contains front contacts D3 which close when relay D is energized.
  • the memory device transmits a signal for regulating the trimmer bin control mechanism 37 the same as when the automatic control means is connected.
  • Timer circuit FIGURE 3 is a schematic wiring diagram of a preferred timer circuit.
  • the circuit includes another relay E, two interval timers and 91, and a switch 92 for setting the control to manna or automatica Timers 90 and 91 are of a type which have an adjustable Volt-time and an adjustable on-time that repeat as long as the timer is running.
  • Such timers per se are known and are available commercially; hence no detailed showing is deemed necessary.
  • Thecircuit is energized from two lines 93 and 94 connected to a suitable voltage source.
  • Switch 92 and theV coil of relay D are connected in series across lines 93 and 91%. Forautomatic operation the switch is open and the'relay deenergized, and for manual openation the reverse. Relay D has a back contact D4 which connects the other relays and the timers to line 93 as long as relay D is deenergized, but breaks this connection when the relay is energized.
  • Timer 90 runs all the while the control is set for automatic operation. It has Va contact 90a which opens during its off-time and closes duringits on-time.
  • the on-time defines the interval t, hereinbefore referred to,
  • Conf 9 relay A picks up, its front contacts A1 and A2 close to operate servomotors 59 and 63 of the divider 57 and integrator 66 respectively, as already described.
  • the coil of relay E, a front contact A3 of relay A, and a back contact C2 of relay C lare connected in series across lines 93 and $4, whereby relay E picks up with relay A.
  • Relay E has a front contact E1 through which it seals in, bypassing contact A3.
  • the coil of relay B, a back contact E2 of relay E, and a back contact C3 of relay C are connected in series across lines 93 and 94, whereby relay B is normally energized, but drops out when relay B picks up.
  • contacts B1 and B2 close to apply the voltages from arm 64 of potentiometer 65 and from the tachometer-generator 69 to the input terminals of the amplifier 67 of the integrator; contacts B3 and B4 open to break the connections to the ground 74 and to the arm 72 of potentiometer 73.
  • Contacts B5 open so that the servomotor 68 can be energized only via contacts A2. Since relay B is normally energized, FIGURE 3 shows contacts B1 and B2 open even though they actually are back contacts, and contacts B3, B4 and B5 closed even though they actually are front contacts.
  • Another front contact A.; of relay A and timer 91 are connected in series across lines 93 and 94, whereby timer 91 is energized when relay A picks up.
  • Timer 91 does not run continuously like timer 99, but is set to operate through only a single cycle of ott-time and onetime whenever it is energized. Otherwise any synchronization errors in the timers would be cumulative, and soon would upset the sequence of operations.
  • Timer 91 is also connected to line 93 through a conductor 95 and remains energized through this conductor after relay A drops out. The on-time of timer 90 ends an instant before the on-time of timer 91 commences.
  • contact 90a opens, relay A drops out, and servomotors S9 and 63 stop.
  • the on-time of timer 91 commences, the timer closes a contact 91a which is connected in series with the coil ofrelay C across lines 93 and 94.
  • Relay C picks up and closes its contacts C1 to operate the servomotor 77 of the memory device 75.
  • the amplifier 76 of the meinory device remains connected to arm 72 of potentiometer 73.
  • the on-time of timer 91 is sufficient that the servomotor 77 operates long enough to set the memory device to the corrected feed rate F0. Subsequently timer 91 is deenergized, whereupon contact 91a opens, and relay C drops out.
  • relay C When relay C picks up, its back contacts C2 and C3 open. Opening of contact C2 drops out relay E, but opening of Contact C3 for the moment prevents relay B from picking up.
  • relay B picks up, whereupon its contacts B3 and B4 connect the amplifier 67 of the integrator to ground 74 and to the potentiometer arm 72, and its contacts B energize the servomotor 68.
  • the potentiometer 73 is reset. It should be noted that relay B cannot be energized until both relays A and C are deenergized; consequently, the potentiometer 73 can be reset only when resetting does not interfere with other operations.
  • FIGURE 4 shows a typical sequence diagram for our feed rate control mechanism when set for automatic operation. Initially timer 9e) is running but is registering ofi-time, timer 91 is stopped, and relay B is energized. Thus no computation is taking place and relay B maintains the integrator 66 and potentiometer -arm 72 in a reset or zero position. Presently the on-time of timer 91) commences. The timer circuit already described drops out relay B and starts timer 91, which at iirst registers ott-time. The divider 57 and integrator 66 now make their computation of a corrected feed rate, and potentiometer arm 72 is positioned accordingly.
  • ignal (a) and the ore feed rate are corrected simultaneously with the positioning of arm 82. Subsequently the on-time of timer 91 ends and this timer stops. Relay B picks up to reset the potentiometer arm 72, but the potentiometer arm 82 retains its setting until a new computation is made.
  • the interval between computations should approximate the time required for a particle to travel from the trimmer bins 16 to the discharge end of grate 29, typically about 4S minutes.
  • the duration of a computation should be suiiicient to furnish a representative average of conditions prevalent on the grate, typically about 1 to 2 minutes.
  • the interval for setting the memory device should be long enough only for the parts to reach their computed positions, allowing a reasonable margin, typically about 15 to 30 seconds.
  • timer 90 can be set for about 45 minutes o-time and about 1 to 2 minutes on-time, and timer 91 for oit-time an instant longer than the on-time of timer 90 and about 15 to 30 seconds on-time.
  • FIGURE 5 shows the grate speed control mechanism 33 in more detail.
  • This mechanism comprises a speed computing circuit 98 and a motor control 99.
  • the speed computing circuit 98 computes a new grate speed which equals the algebraic sum of the instant speed, a temporary increment (positive or negative) to return the depth to the desired range, and a permanent increment (positive or negative) to hold it in the desired range after it has returned. Both increments are of course negative when the bed is too shallow and positive when it is too deep.
  • the circuit 98 computes another new speed which equals the instant speed with the temporary increment discontinued.
  • the speed computing circuit 98 acts periodically, but its cycle is short (for example 5 seconds computing and 5 seconds between computations), whereby the mechanism etlectually exercises continuous control over the grate speed.
  • the speed computing circuit 98 is energized through lines 1110 and 161 connected to a suitable D.C. source.
  • the low level sensing means 34 controls a contact 34a which is connected across these lines in series with the coil of a relay H.
  • the high level Sensing means 35 controls a contact 35a which is connected across these lines in series with the coil of a relay 1.
  • both contacts 34a and 35a open and both relays H and .l are deenergized.
  • contact 34a closes and relay H picks up.
  • both contacts 34a and 35a close and both relays H and .l pick up.
  • Relays H and I control a pair of relays K and L, which in turn control the application of negative and positive temporary speed change increments respectively.
  • relay K is connected acrosslines '100 and 101 in series with a back contact H1 of relay H and a front contact T1 controlled by a timer T.
  • the coil of relay L is connected across these lines in series with a front contact J1 of relay I and a front contact T2 of the timer.
  • Timer T automatically and periodically opens and closes its contacts for brief intervals. If the bed depth is within the desired range when the timer closes its contacts T1 and T2, neither relay K nor L picks up, since both contacts H1 and J1 remain open. If the bed istoo shallow, relay K picks up with the closing of timer contact T1, since relay H is deenergized and its contact H1 closed.
  • relay L picks up with the closing of timer contact T2, since relay J is energized and its Contact I1 closed.
  • relay K or L picks up, it seals in via back Contact T3 or T., of the timer and its own front contact K1 or L1.
  • Relays K and L are relatively slowacting to enable them to remain energized during the interval contacts T1 and T2 are opening and contacts T3 and 'T4 closing.
  • contact H1 or I1 immediately opens. The next time timer T opens its contacts T3 and T4, relay K or L drops out and the temporary increment is discontinued.
  • Relays H and J also ⁇ control a reversing motor 102 which in turn controls the application of permanent speed change increments.
  • This motor is connected across lines 100 and itil in series with back contacts H2 and H3 of relay H and front contacts T5 and T6 of timer T for energizing it in one direction, and in series with front contacts I2 and J3 of relay l' and the same contacts T5 and T5 for energizing it in the opposite direction, If the bed depth is within the desired range when timer T closes its contacts T 5 and T6, the motor does not operate, since contacts H2, H3, I2 and J3 are all'open.
  • the circuit vin cludes a potentiometer 163 whose slide wire is connected to a suitable D.C. source for developing a speed controlling voltage.
  • the potentiometer has an arm Illdwhich is electrically connected to an output terminal 105 via two variable resistances 106 and 107 in series,
  • the motor control 99 illustrated includes a motor-generator 108 and a magnetic amplifier 169 which has Aa control winding 110.
  • the magnetic amplifier and motor por- ⁇ VVtion of the motor-generator are connected to suitable fn-C. sources.
  • 1Terminal 1.05 of thespeed computing circuit is electrically connected tothe Winding 1141i and continuously transmits thereto a voltage proportionate to the most recently computed speed for motorfil. ⁇
  • the magnetic amplifier isconnected to a lield winding i12 of the D.C. generator, whereby the voltage appliedrto the field winding, and hence the voltage output of the generator, vary with the voltage applied to the control winding llt).
  • the generator is electricallyl connected lto the D.C.
  • the mechanism then automatically controls the feed rate and grate speed to hold theburn-through point at this location. Similar results can be attained by using the individual control devices shown in our other applications, ,except that it is necessary also to usel a surge bin between the compounding apparatus and the sintering machine.
  • the present invention overcomes any need for a surge bin,
  • a sintering installation which includes a traveling grate sintering machine, apparatus for assembling and mixing ingredients of a combustible sinter mix and feed- Ying the mix to said machine, and a burn-through indicator -operatively connected with said machine, the combination therewith of a control mechanism comprising computing means operatively connected with said indicator for computing feed rates -to hold the burn-through point at a set location on the grate, and means operatively connected with said computing kmeans Vand said'apparatus' for regulating the quantity of sinter mix fed Yto said machine ⁇ in accordanceV with computed rates.
  • a sintering installation which includes a traveling -grate sintering machine,apparatus for assembling and -mixing ingredients of a combustible sinter mix and feedance with computed rates, and means operatively connected with said'machine to regulatek the speed at which ⁇ its grate travels to maintain the depth of the .bed Within .a predetermined range.
  • a sintering installation which includes a ,traveling Ygrate sintering machine, apparatus for assembling and mixing ingredients to form a combustible sinter mixand 'feeding the mix to said machine, and a burn-through indicator operatively connected with said machine, the comrbination therewith of a control mechanism comprising a ,set-point indicator, computing means .operatively con- 751nected1with said indicators for periodically computing 13 a new feed rate to shift the burn-through point from its actual location on the grate indicated by said burnthrough indicator to a set location indicated by said setpoint indicator, means operatively connected with said computing means and said apparatus for regulating the quantity of sinter mix fed to said machine in accordance with computed rates, and timingr means operatively connected with said computing means ⁇ for regulating the period between successive operations thereof to approximately the time taken for mix of corrected feed rate to reach the discharge end of the grate.
  • said computing means includes means for averaging the computation of a new feed rate over a sufficient period to eliminate effects of minor fluctuations.
  • a control mechanism comprising a set-point indicator, computing means operatively connected with said indicators for periodically computing a new feed rate to shift the burn-through point of the bed from its actual location on the grate indicated by said burn-through indicator to a set location indicated by said set-point indicator, means operatively connected with said computing means and said apparatus for regulating the quantity of sinter mix fed to said machine in accordance with computed rates, timing means operatively connected with said computing means for regulating the period between successive operations thereof to approximately the time taken for mix of corrected feed rate to reach the discharge end of the grate, and means operatively connected with said machine to regulate the speed at which its grate travels to maintain the depth of the bed within
  • a control mechanism comprising a set-point indicator, a first computing means operatively connected with said indicators for determining as a ratio any discrepancy between the actual location of the burn-through point on the grate indicated by said burn-through indicator and the set location indicated by said set-point indicator, a second computing means operatively connected with said first computing means for periodically computing as an average over a period suicient to eliminate effects of minor fluctuations a new feed rate to shift the burn-through point from its actual location to its set location, means operatively connected with said second computing means and said apparatus for regulating the quantity of sinter mix fed to said machine in accordance with computed rates, and timing means operatively connected with said second computing means for regulating the period between successive operations thereof to approximately the time
  • a sintering installation which includes a traveling grate sintering machine, apparatus for assembling and mixing ingredients of a combustible sinter mix and feeding the mix to said machine to form a bed on the grate thereof, and a burn-through indicator operativelyrconnected with said machine, the combination therewith of va control mechanism comprising a set-point indicator,
  • a first computing means operatively connected with said indicators for determining as a ratio any discrepancy between the actual location on the grate of the burn-through point of the bed indicated by said burn-through indicator p and the set location indicated by said set-point indicator,
  • a second computing means operatively connected with said rst computing means for periodically computing as i4 Y Y an average over a period sufficient to eliminate effects of minor fluctuations a new feed rate to shift the burnthrough point from its actual location to its set location
  • means operatively connected with said second computing means and said apparatus for regulating the quantity of sinter mix fed to said machine in accordance with cornputed rates
  • timing means operatively connected with said second computing means for regulating the period between successive operations thereof to approximately the time taken for mix of corrected feed rate to reach the discharge end of the grate
  • means operatively connected with said machine to regulate the speed at which its grate travels to maintain the depth of the bed within a predetermined range.
  • a sintering installation which includes a traveling grate sintering machine, a compounding apparatus for assembling ore, additives and hot recycle, means operatively connected with said apparatus for proportioning the rate at which additives are included in accordance with the sum of the ore and hot recycle rates, and means for mixing materials assembled in said apparatus and feeding them to said machine, the combination therewith of a control mechanism comprising computing means operatively connected with said machine for computing feed rates required to hold the burn-through point at a set location on the grate, and means operatively connected with said computing means and said apparatus for adjusting the sum of the ore and hot recycle rates in accordance with the computed feed rate.
  • a sintering installation which includes a traveling grate sintering machine, a compounding apparatus for assembling ore, additives and hot recycle, means operatively connected with said apparatus for proportioning the rate at which additives are included in accordance with the sum of the ore and hot recycle rates, and means for mixing materials assembled in said apparatus and feeding them to said machine to form a bed on the grate thereof, the combination therewith of a control mechanism comprising computing means operatively connected with said machine for computing feed rates required to hold the burn-through point of the bed at a set location on the grate, means operatively connected with said computing means and said apparatus for adjusting the sum of the ore and hot recycle rates in accordance with the computed feed rate, and means operatively connected with said machine to regulate the speed at which its grate travels to mainta-in the depth of the bed within a predetermined range,
  • a sintering installation which includes a traveling grate sintering machine, a compounding apparatus for assembling ore, additives and hot recycle, means operatively connected with said apparatus for regulating the rate at which hot recycle is included at substantially the rate received, means operatively connected with said .apparatus for proportioning the rate at which additives are included in accordance with the sum of the ore and hot recycle rates, and means for mixing materials assembled in said apparatus and feeding them to said machine, the combination therewith of a control mechanism comprising computing means operatively connected with said machine for computing feed rates required to hold the burn-through point at a set location on the grate, and means operatively connected with said computing means and said apparatus for adjusting the ore rate to values at which the sum of the ore and hot recycle rates is in accordance with the computed feed rate.
  • a sintering installation which includes a traveling grate sintering machine, a compounding apparatus for assembling ore, additives and hot recycle, means operatively connected with said apparatus for proportioning the rate at which additives are included in accordance with the sum of the ore and hot recycle rates, means for mixing materials assembled in said apparatus and feeding them to said machine, and a burn-through indicator operatively connected with said machine, the combination therewith of a control mechanism comprising a set-point indicator, computing means operatively connected with said indicators for periodically computing a new feed rate to shift the burn-through point from its actual location on the grate indicated by said burn-through indicator toa set location indicated by said set-point indicator, means operatively connected with said cornputing means and said apparatus for adjusting the sum of the ore and hot recycle rates in accordance with the computed feed rate, and timing means operatively connected with said computing means for regulating the period between successive operations thereof to approximately the time taken for mix of corrected feed rate to reach the discharge end of the grate
  • a method of controlling a traveling grate sintering operation comprising periodically computing rates of feeding material to the grate to shift the burn-through point from its actual location to a set location, changing the feed rate to the computed rate, and regulating the speed at which the grate travels to maintain the depth of material thereon within a predetermined range.
  • a method of control comprising periodically computing a new feed rate to shift the burn-through point of the bed from its actual location on the grate to a set location, changing the sum of the ore and hot recycle rates in accordance with the computed new rate, proportioning additives in accordance with this sum, the period between successive computing steps approximating the time taken for material of a new feed rate to reach 'the discharge end of the grate and regulating the speed at which the grate travels to maintain the depth of the bed within a predetermined range.
  • a sintering installation which includes a traveling gratesintering machine, apparatus for assembling and mixing ingredients of a combustible sinter mix and feeding the mix to said machine to form a bed on the grate thereof, and a burn-through indicator operatively connected with said machine for indicating the actual location of the burn-through point on the grate
  • a control mechanism comprising a set point indicator for indicating the desired Vlocation of the burn-through point, respective voltage sources operatively connected with said indicators for developing a first voltage which varies with the actual location of the burn-through point and a second voltage which varies with the desired location, a divider operatively connected with said voltage sources for determining the ratio of said voltages ⁇ and thus determining the magnitude of any discrepancy between the actual and desired locations, means for developing a third voltage propor ⁇ tionate to the instant feed rate of sinter mix to said sintering machine, multiplying means operatively connected with said last named means and said dividerfor developing
  • a control mechanism comprising a set lrpoint indicator for indicating the desired location of the burn-through point, respective voltage sources operatively connected with said indicators for developing a first voltage which varies with theactual location of the burnthroughpoint and a second voltage which varies with the desired location, a divider operatively connected with said voltage sources for determining the ratio of said voltages and'thus determining the magnitude of any discrepancy between the actual and desired locations, means for developing a third voltage proportionate to the instant feed rate of sinter mix to said sintering machine, multiplying means operatively connected with said last named
  • a sintering installation which includes a traveling rgrate sintering machine, apparatus for assembling and mixing ingredients of a combustible sinter mix and feeding the mix to said machine to form a bed on the grate thereof, andahum-through indicator operatively connected with said machine for indicating the actual location of the burn-through point on the grate, the combination therewith of a control mechanism comprising a set ,point indicator for indicating the desired location of the burn-through point, respective voltage-sources operatively connected with said indicators for developing a first voltage which varies with the actual location of the burnthrough point and a secondY voltage which varies with the desired location, a divider operatively.
  • a sintering installation which includes a travelmg grate sintering machine, apparatus for assembling and vmixing ingredients of a combustible sinter mix and feeding the mix to said machine Vto form a bed on the grate thereof, and a burn-through indicator operativelyconnected with said machine for indicating the actual location of the burn-through point on the grate, the combinai?
  • a control mechanism comprising a set point indicator for indicating the desired location of the burn-through point, respective voltage sources operatively connected with sa-id indicators for developing a first Volt age which varies with the actual location of the burnthrough point and a second voltage which varies with the desired loc-ation, a divider operatively connected with said voltage sources for determining the ratio of said voltages and thus determining the magnitude of any discrepancy between the actual and desired locations, means for developing a third voltage proportionate to the instant feed rate of sinter mix to said sintering machine, multiplying means operatively connected with said last named means and said divider for developing a fourth voltage proportionate to the product of said third voltage and said ratio and thus determining a corrected feed rate to shift the burn-through point to the desired location, an integrator operatively connected with said multiplying means for developing periodically a fifth voltage proportionate to said fourth voltage averaged over an interval sufficient to eliminate effects of minor iluctuations in the actual location, a memory device operatively

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US758106A US3194546A (en) 1958-08-29 1958-08-29 Mechanism and method for controlling sintering
GB27924/59A GB906394A (en) 1958-08-29 1959-08-14 Mechanism and method for controlling sintering
BE581992A BE581992A (fr) 1958-08-29 1959-08-25 Mécanisme et procédé pour la conduite d'opérations de frittage
FR803729A FR1249834A (fr) 1958-08-29 1959-08-27 Mécanisme et procédé pour la conduite d'opérations de frittage
DEU6460A DE1142619B (de) 1958-08-29 1959-08-28 Regeleinrichtung fuer eine Sinteranlage

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Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3615344A (en) * 1967-12-01 1971-10-26 Centre Nat Rech Metall Methods of controlling the process of agglomeration
US3746537A (en) * 1971-08-27 1973-07-17 Dravo Corp Process and apparatus for the control of the speed of movement of sinter strand
US3772958A (en) * 1971-06-16 1973-11-20 Thermal Reduction Corp Apparatus for ammunition disposal
US3779077A (en) * 1972-04-10 1973-12-18 Siderurgie Fse Inst Rech Method and apparatus for establishing the firing temperature curve of a sintering charge
US3793101A (en) * 1971-06-16 1974-02-19 Thermal Reduction Corp Method for ammunition disposal
US4120643A (en) * 1975-01-15 1978-10-17 Delattre-Levivier Method of regulating the process of agglomeration of a mineral on an endless chain
DE3039854A1 (de) * 1979-10-22 1981-04-30 Asarco Inc., New York, N.Y. Verfahren und anordnung zum abkuehlen einer sinterschicht
US4416394A (en) * 1981-08-20 1983-11-22 Vsesojuzny Nauchno-Issledovatelsky I Proektno-Konstruktorsky Institut Po Avtomatizatsil Predpriyaty Promyshlennosti Stroitelnykh Materialov Regulating apparatus for automatically controlling the production of a comminuted mixture having prescribed composition
US4501412A (en) * 1979-10-22 1985-02-26 Asarco Incorporated Non-polluting heat recuperative sintering method and apparatus
US5857847A (en) * 1997-04-17 1999-01-12 Chrysler Corporation Brazing furnace parts feeding control
CN105716987A (zh) * 2016-05-05 2016-06-29 中冶北方（大连）工程技术有限公司 一种烧结配合料水分检测分析装置及其分析方法

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US2047579A (en) * 1933-08-31 1936-07-14 Mid Continent Invest Company Thermostatic stoker control
US2055941A (en) * 1932-08-22 1936-09-29 Allis Chalmers Mfg Co Cooler
US2273126A (en) * 1939-08-10 1942-02-17 Brown Instr Co Control system
US2410944A (en) * 1943-05-13 1946-11-12 American Smelting Refining System for sintering
US2796197A (en) * 1955-03-08 1957-06-18 American Mach & Foundry Anti-hunting system for electrical regulators
US2878003A (en) * 1956-08-08 1959-03-17 United States Steel Corp System for determining peak location of temperature

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2055941A (en) * 1932-08-22 1936-09-29 Allis Chalmers Mfg Co Cooler
US2047579A (en) * 1933-08-31 1936-07-14 Mid Continent Invest Company Thermostatic stoker control
US2273126A (en) * 1939-08-10 1942-02-17 Brown Instr Co Control system
US2410944A (en) * 1943-05-13 1946-11-12 American Smelting Refining System for sintering
US2796197A (en) * 1955-03-08 1957-06-18 American Mach & Foundry Anti-hunting system for electrical regulators
US2878003A (en) * 1956-08-08 1959-03-17 United States Steel Corp System for determining peak location of temperature

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3615344A (en) * 1967-12-01 1971-10-26 Centre Nat Rech Metall Methods of controlling the process of agglomeration
US3772958A (en) * 1971-06-16 1973-11-20 Thermal Reduction Corp Apparatus for ammunition disposal
US3793101A (en) * 1971-06-16 1974-02-19 Thermal Reduction Corp Method for ammunition disposal
US3746537A (en) * 1971-08-27 1973-07-17 Dravo Corp Process and apparatus for the control of the speed of movement of sinter strand
US3779077A (en) * 1972-04-10 1973-12-18 Siderurgie Fse Inst Rech Method and apparatus for establishing the firing temperature curve of a sintering charge
US4120643A (en) * 1975-01-15 1978-10-17 Delattre-Levivier Method of regulating the process of agglomeration of a mineral on an endless chain
DE3039854A1 (de) * 1979-10-22 1981-04-30 Asarco Inc., New York, N.Y. Verfahren und anordnung zum abkuehlen einer sinterschicht
US4337083A (en) * 1979-10-22 1982-06-29 Asarco Incorporated Non-polluting, cooling method and heat recuperative sintering method
US4501412A (en) * 1979-10-22 1985-02-26 Asarco Incorporated Non-polluting heat recuperative sintering method and apparatus
US4416394A (en) * 1981-08-20 1983-11-22 Vsesojuzny Nauchno-Issledovatelsky I Proektno-Konstruktorsky Institut Po Avtomatizatsil Predpriyaty Promyshlennosti Stroitelnykh Materialov Regulating apparatus for automatically controlling the production of a comminuted mixture having prescribed composition
US5857847A (en) * 1997-04-17 1999-01-12 Chrysler Corporation Brazing furnace parts feeding control
CN105716987A (zh) * 2016-05-05 2016-06-29 中冶北方（大连）工程技术有限公司 一种烧结配合料水分检测分析装置及其分析方法
CN105716987B (zh) * 2016-05-05 2018-06-29 中冶北方（大连）工程技术有限公司 一种烧结配合料水分检测分析装置及其分析方法

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GB906394A (en) 1962-09-19
BE581992A (fr) 1960-02-25

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