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EP0204935B1 - Method for controlling the charging of a shaft furnace - Google Patents

Method for controlling the charging of a shaft furnace Download PDF

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Publication number
EP0204935B1
EP0204935B1 EP86105644A EP86105644A EP0204935B1 EP 0204935 B1 EP0204935 B1 EP 0204935B1 EP 86105644 A EP86105644 A EP 86105644A EP 86105644 A EP86105644 A EP 86105644A EP 0204935 B1 EP0204935 B1 EP 0204935B1
Authority
EP
European Patent Office
Prior art keywords
valve
flow
hopper
charging
real
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
Application number
EP86105644A
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German (de)
French (fr)
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EP0204935A1 (en
Inventor
Gilbert Bernard
Emile Breden
Emile Lonardi
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Paul Wurth SA
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Paul Wurth SA
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Publication date
Application filed by Paul Wurth SA filed Critical Paul Wurth SA
Priority to AT86105644T priority Critical patent/ATE41679T1/en
Publication of EP0204935A1 publication Critical patent/EP0204935A1/en
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Publication of EP0204935B1 publication Critical patent/EP0204935B1/en
Expired legal-status Critical Current

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    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21BMANUFACTURE OF IRON OR STEEL
    • C21B7/00Blast furnaces
    • C21B7/18Bell-and-hopper arrangements
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21BMANUFACTURE OF IRON OR STEEL
    • C21B7/00Blast furnaces
    • C21B7/18Bell-and-hopper arrangements
    • C21B7/20Bell-and-hopper arrangements with appliances for distributing the burden
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27FURNACES; KILNS; OVENS; RETORTS
    • F27BFURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B1/00Shaft or like vertical or substantially vertical furnaces
    • F27B1/10Details, accessories or equipment specially adapted for furnaces of these types
    • F27B1/20Arrangements of devices for charging

Definitions

  • the present invention relates to a method for controlling the loading of a shaft furnace, comprising a rotary or oscillating distribution chute for ensuring the distribution of the material on the loading surface of the furnace, one or more hoppers for storing the material in the above the oven, each provided with a metering valve for adjusting the flow rate of the loading material flowing from the hopper to the chute, a weighing system for determining the content of the hopper, method according to which it is determined, by calculation or experiment, the initial degree of opening of the valve so that the content of a hopper flows in a determined time, we memorize, for different types of material and different loading conditions, the theoretical curves of a flow constant determined as well as the corresponding position of the metering valve to ensure flow over the determined time, these curves providing at all times the set flow rate Q c and the position of the valve and, the actual flow rate Q is established at determined intervals, by measuring the reduction in weight AP of the content of the hopper per unit of time At and the actual flow rate Q is compared with the
  • a shaft furnace When loading a shaft furnace using a distribution chute, it is generally arranged so as to deposit a layer, with diametrical symmetry and circular uniformity, on the loading surface using the contents d 'a storage hopper.
  • a predetermined time imposed by the efficiency and capacity of the furnace, the distribution method and the coordination of operations, such as opening, closing of the valves, supply of the loading material, etc. Knowing therefore this available time, it is necessary to adjust the opening of the metering valve controlling the flow out of the hopper so that it empties at the moment when the chute ends its scanning phase at the expiration of the imposed time.
  • the reduction in weight reduces the thrust on the flow so that the flow falls below the set flow. Because of this slowing, one necessarily exceeds the time imposed by the loading of the contents of a hopper into the oven, which not only disturbs the loading program, but in addition, is the cause of non-symmetrical loading, c that is, the height of the deposited layer is irregular in the circular direction of the loading surface. Other factors, such as the humidity level or the grain size of the loading material, can influence the flow rate.
  • the object of the present invention is to provide a new method for operating the metering valve so as to ensure an almost uniform flow corresponding to the set flow.
  • the method proposed by the present invention is characterized in that the metering flap is opened each time the actual flow is less than the set flow and in that it is maintained in position when the actual flow is higher than the set flow.
  • the valve is opened at an amplitude AS which corresponds to the difference between the position of the valve corresponding to the set flow rate Q c and that corresponding to the actual flow Q ,.
  • the actuation speed of the valve is proportional to the difference AS, that is to say if this difference AS is large, the valve is moved relatively quickly, whereas if this difference AS is weak, the valve is moved slowly.
  • AS the difference between the two valves.
  • Figure 1 shows, in bold lines, the curve representing the actual weight P ,, that is to say the measured weight while the curve in dashed lines represents the target weight P c which should allow a uniform flow of the loading material in the imposed time T.
  • the gradient of these curves that is to say represents the flow rate which is constant for the curve P c .
  • the horizontal evolution of the flow rate of each of the curves P, and P c represents the phase of opening of the metering valve.
  • the reduction in weight of the hopper should be linear to ensure constant flow corresponding to the set flow Q c .
  • the evolution of the two curves shows, from a certain moment, the difference between the weight and the material which is actually in the hopper and that of the material which should still be there to respect the constant flow Q c becomes larger and larger and the hopper will not be empty until well beyond the imposed time T.
  • FIG. 4 shows the head of an oven 10 in which there is a chute 12 driven by a drive device 14 to rotate it around the axis of the oven and adjust its angle of discharge.
  • a frame 16 carried by the oven 10 supports, via a series of load cells 20, a hopper 18. These load cells constantly provide information on the weight of the hopper 18 and, consequently, on its content.
  • the flow orifice of this hopper 18 is controlled by a metering valve 22 which can be composed of two registers with symmetrical movement around the axis of the oven.
  • This metering valve 22 is actuated by a hydraulic cylinder 24, while the actual position of the valve is constantly determined by a position detector 26.
  • the hydraulic cylinder 24 controlling the position of the metering valve 22 is actuated by a hydraulic valve 28 with proportional action which receives the oil under pressure from a hydraulic unit 30.
  • the control circuit also includes a computer 32 for carrying out the operations of calculation and memorizing all the necessary information. The information from this computer 32 is transmitted to a control unit 34 which controls the hydraulic valve 28 to regulate the oil flow, that is to say the operating speed of the hydraulic cylinder 24 and of the valve 22.
  • the oil flow rate is adjusted by the valve 28 on the order of the control unit 34 as a function of the quantity AS, that is to say that the valve 28 is moved faster when AS is large, and conversely, is moved more and more slowly as AS decreases. It is even preferable to stop the valve when AS reaches a predetermined lower limit to be certain to avoid that the valve does not exceed its set position and possibly risk thus finding itself in the situation of FIG. 2.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Filling Or Emptying Of Bunkers, Hoppers, And Tanks (AREA)
  • Vertical, Hearth, Or Arc Furnaces (AREA)
  • Heat Treatment Of Articles (AREA)
  • Blast Furnaces (AREA)
  • Control Of High-Frequency Heating Circuits (AREA)
  • Looms (AREA)
  • Cookers (AREA)
  • Electric Stoves And Ranges (AREA)

Abstract

A process for controlling the charging of a shaft furnace of the type utilizing a distribution spout and one or more storage hoppers with each hopper being provided with a dosing device for regulating the flow of charging material from the hopper to the spout. The shaft furnace also includes a weighing system to determine the contents (weight) of the hopper and to adjust the position of the dosing device wherein the dosing valve is opened whenever the real flow Qr is below the reference flow Qc and is held in position when the real flow Qr is above the reference flow Qc.

Description

La présente invention concerne un procédé de contrôle du chargement d'un four à cuve, comprenant une goulotte de distribution rotative ou oscillante pour assurer la distribution de la matière sur la surface de chargement du four, une ou plusieurs trémies de stockage de la matière au-dessus du four, pourvues chacune d'un clapet de dosage pour régler le débit de la matière de chargement s'écoulant de la trémie vers la goulotte, un système de pesée pour déterminer le contenu de la trémie, procédé selon lequel on détermine, par calcul ou expérimentation, le degré d'ouverture initial du clapet pour que le contenu d'une trémie s'écoule en un temps déterminé, on mémorise, pour différents types de matière et différentes conditions de chargement, les courbes théoriques d'un débit constant déterminé ainsi que de la position correspondante du clapet de dosage oour assurer l'écoulement dans le temps déterminé, ces courbes fournissant à chaque instant le débit de consigne Qc et la position du clapet, on établit à intervalles déterminés le débit réel Q, en mesurant la diminution de poids AP du contenu de la trémie par unité de temps At et l'on compare le débit réel Q, au débit de consigne Qc.The present invention relates to a method for controlling the loading of a shaft furnace, comprising a rotary or oscillating distribution chute for ensuring the distribution of the material on the loading surface of the furnace, one or more hoppers for storing the material in the above the oven, each provided with a metering valve for adjusting the flow rate of the loading material flowing from the hopper to the chute, a weighing system for determining the content of the hopper, method according to which it is determined, by calculation or experiment, the initial degree of opening of the valve so that the content of a hopper flows in a determined time, we memorize, for different types of material and different loading conditions, the theoretical curves of a flow constant determined as well as the corresponding position of the metering valve to ensure flow over the determined time, these curves providing at all times the set flow rate Q c and the position of the valve and, the actual flow rate Q is established at determined intervals, by measuring the reduction in weight AP of the content of the hopper per unit of time At and the actual flow rate Q is compared with the reference flow rate Q c .

Lors du chargement d'un four à cuve à l'aide d'une goulotte de distribution, on s'arrange généralement de manière à déposer une couche, à symétrie diamétrale et uniformité circulaire sur la surface de chargement à l'aide du contenu d'une trémie de stockage. A cet effet, on dispose généralement d'un temps prédéterminé imposé par le rendement et la capacité du four, le mode de distribution et-la- coordination des opérations, telles que ouverture, fermeture des clapets, amenée de la matière de chargement etc. Connaissant donc ce temps disponible, il faut régler l'ouverture du clapet de dosage contrôlant l'écoulement hors de la trémie de manière que celle-ci se vide au moment où la goulotte termine sa phase de balayage à l'expiration du temps imposé.When loading a shaft furnace using a distribution chute, it is generally arranged so as to deposit a layer, with diametrical symmetry and circular uniformity, on the loading surface using the contents d 'a storage hopper. For this purpose, there is generally a predetermined time imposed by the efficiency and capacity of the furnace, the distribution method and the coordination of operations, such as opening, closing of the valves, supply of the loading material, etc. Knowing therefore this available time, it is necessary to adjust the opening of the metering valve controlling the flow out of the hopper so that it empties at the moment when the chute ends its scanning phase at the expiration of the imposed time.

Le réglage du clapet est réalisé, à cet effet, de la manière indiquée ci-dessus et comme décrit également dans les brevets US 3 929 240 et 4 074 816. Théoriquement, un réglage effectué de cette manière devrait permettre le dépôt d'une couche telle que souhaitée par les sidérurgistes. En pratique, il n'en est malheureusement pas ainsi, car certains paramètres peuvent influencer le débit d'écoulement, indépendamment de la position du clapet. Ainsi, par exemple, lorsque l'on choisit la position d'ouverture du clapet à partir de données étalon mémorisées et suivant la nature du matériau à charger afin d'obtenir un débit bien déterminé, on constate qu'en début de la phase d'écoulement le poids de la colonne des matières se trouvant au-dessus de l'ouverture d'écoulement peut provoquer une augmentation du débit. Par contre, au fur et à mesure de la vidange de la trémie, la diminution du poids réduit la poussée sur l'écoulement de sorte que le débit tombe en-dessous du débit de consigne. A cause de ce ralentissement, on dépasse nécessairement le temps imposé par le chargement du contenu d'une trémie dans le four, ce qui non seulement perturbe le programme de chargement, mais en plus, est la cause d'un chargement non symétrique, c'est-à-dire que la hauteur de la couche déposée est irrégulière dans le sens circulaire de la surface de chargement. D'autres facteurs, comme par exemple le degré d'humidité ou la granulométrie du matériau de chargement, peuvent influencer le débit.The adjustment of the valve is carried out, for this purpose, in the manner indicated above and as also described in US Patents 3,929,240 and 4,074,816. Theoretically, an adjustment carried out in this way should allow the deposition of a layer as desired by the steelmakers. In practice, this is unfortunately not the case, because certain parameters can influence the flow rate, regardless of the position of the valve. Thus, for example, when the opening position of the valve is chosen from stored standard data and according to the nature of the material to be loaded in order to obtain a well-determined flow rate, it can be seen that at the start of the phase d The weight of the column of materials above the flow opening can cause an increase in flow. On the other hand, as the hopper is emptied, the reduction in weight reduces the thrust on the flow so that the flow falls below the set flow. Because of this slowing, one necessarily exceeds the time imposed by the loading of the contents of a hopper into the oven, which not only disturbs the loading program, but in addition, is the cause of non-symmetrical loading, c that is, the height of the deposited layer is irregular in the circular direction of the loading surface. Other factors, such as the humidity level or the grain size of the loading material, can influence the flow rate.

Pour y remédier, on a essayé de corriger la position du clapet de dosage en fonction des fluctuations du débit, c'est-à-dire que l'on ferme légèrement le clapet lorsque le débit réel mesuré par la diminution du poids de la trémie est supérieur au débit de consigne et que l'on ouvre davantage le clapet lorsque le débit tombe au-dessous de la valeur de consigne. Toutefois, en réalité, la détermination du débit pour une position bien précise du clapet n'est possible qu'après que cette position ait été atteinte et, compte tenu du laps de temps nécessaire à la détermination du débit, la position idéale ou de consigne du clapet lors des corrections de position esttoujours atteinte, avant que l'on puisse le savoir. Autrement dit, quel que soit le sens de déplacement du clapet, c'est-à-dire ouverture ou fermeture, il est toujours déplacé trop loin et il est nécessaire d'effectuer des corrections successives et alternativement en sens opposé. Le résultat est que le débit réel oscille constamment autour de la valeur de consigne.To remedy this, an attempt was made to correct the position of the metering valve as a function of fluctuations in the flow rate, that is to say that the valve is closed slightly when the actual flow rate measured by the reduction in the weight of the hopper is greater than the setpoint flow and the valve is opened further when the flow falls below the setpoint. However, in reality, the determination of the flow rate for a very precise position of the valve is only possible after this position has been reached and, taking into account the period of time necessary for the determination of the flow rate, the ideal or setpoint position. of the valve during position corrections is always reached, before we can know. In other words, whatever the direction of movement of the valve, that is to say opening or closing, it is always moved too far and it is necessary to carry out successive corrections and alternately in the opposite direction. The result is that the actual flow fluctuates constantly around the setpoint.

Le seul résultat positif réalisable par ce procédé est que l'on arrive plus ou moins à respecter le temps imposé pour l'écoulement du contenu d'une trémie. Par contre, à cause des fluctuations du débit, le dépôt de la matière de chargement devient encore plus irrégulier que sans corrections. En plus, ce procédé entraîne un inconvénient supplémentaire, dans la mesure-où-les inversions du movemenmt de déplacement du clapet entre ouverture et fermeture et vice-versa provoquent des coups entraînant de fausses impulsions dans le système de mesure du poids.The only positive result achievable by this process is that we more or less respect the time imposed for the flow of the contents of a hopper. On the other hand, because of the fluctuations in the flow rate, the deposition of the loading material becomes even more irregular than without corrections. In addition, this method involves an additional drawback, insofar as the reversals of the movement of movement of the valve between opening and closing and vice versa cause knocks causing false pulses in the weight measurement system.

Le but de la présente invention est de prévoir un nouveau procédé pour manoeuvrer le clapet de dosage de façon à assurer un débit quasi uniforme correspondant au débit de consigne.The object of the present invention is to provide a new method for operating the metering valve so as to ensure an almost uniform flow corresponding to the set flow.

Pour atteindre cet objectif, le procédé proposé par la présente invention est caractérisé en ce que le clapet de dosage est ouvert chaque fois que le débit réel est inférieur au débit de consigne et en ce qu'il est maintenu en position lorsque le débit réel est supérieur au débit de consigne.To achieve this objective, the method proposed by the present invention is characterized in that the metering flap is opened each time the actual flow is less than the set flow and in that it is maintained in position when the actual flow is higher than the set flow.

L'ouverture du clapet est réalisée suivant une amplitude AS qui correspond à la différence entre la position du clapet correspondant au débit de consigne Qc et celle correspondant au débit réel Q,.The valve is opened at an amplitude AS which corresponds to the difference between the position of the valve corresponding to the set flow rate Q c and that corresponding to the actual flow Q ,.

Selon un mode d'exécution avantageux, la vitesse d'actionnement du clapet est proportionnelle à la différence AS, c'est-à-dire si cette différence AS est grande, le clapet est déplacé relativement vite, alors que si cette différence AS est faible, le clapet est déplacé lentement. Comme mesure supplémentaire permettant d'assurer que le clapet ne dépasse pas la position visée, sa vitesse de déplacement devient nulle lorsque la différence AS atteint un minimum prédéterminé.According to an advantageous embodiment, the actuation speed of the valve is proportional to the difference AS, that is to say if this difference AS is large, the valve is moved relatively quickly, whereas if this difference AS is weak, the valve is moved slowly. As an additional measure to ensure that the valve does not exceed the target position, its displacement speed becomes zero when the difference AS reaches a predetermined minimum.

D'autres particularités et caractéristiques ressortiront de la description détaillée d'un mode d'exécution avantageux décrit ci-dessous, en référence aux dessins annexés, dans lesquels:Other particularities and characteristics will emerge from the detailed description of an advantageous embodiment described below, with reference to the appended drawings, in which:

la figure 1 montre la courbe représentant la diminution du poids de la trémie sans correction de la position du clapet;

  • la figure 2 montre la courbe représentant la diminution du poids de la trémie avec correction de la position du clapet dans les deux sens;
  • la figure 3 montre la courbe représentant la diminution en poids de la trémie avec correction de la position du clapet dans un sens seulement selon la présente invention et
  • la figure 4 montre un schéma synoptique d'un dispositif pour la mise en oeuvre de ce procédé selon la présente invention.
Figure 1 shows the curve representing the decrease tion of the hopper weight without correction of the valve position;
  • FIG. 2 shows the curve representing the reduction in the weight of the hopper with correction of the position of the valve in both directions;
  • FIG. 3 shows the curve representing the reduction in weight of the hopper with correction of the valve position in one direction only according to the present invention and
  • FIG. 4 shows a block diagram of a device for implementing this method according to the present invention.

La figure 1 montre, en traits gras, la courbe représentant le poids réel P,, c'est-à-dire le poids mesuré tandis que la courbe en traits mixtes représente le poids de consigne Pc qui devrait permettre un écoulement uniforme de la matière de chargement dans le temps imposé T. Le gradient de ces courbes, c'est--à-dire

Figure imgb0001
représente le débit de l'écoulement qui est constant pour la courbe Pc.Figure 1 shows, in bold lines, the curve representing the actual weight P ,, that is to say the measured weight while the curve in dashed lines represents the target weight P c which should allow a uniform flow of the loading material in the imposed time T. The gradient of these curves, that is to say
Figure imgb0001
represents the flow rate which is constant for the curve P c .

Comme on peut le constater, l'évolution horizontale du débit de chacune des courbes P, et Pc représente la phase d'ouverture du clapet de dosage. Lorsque celui-ci a atteint sa position d'ouverture correspondant au débit de consigne Qc calculé d'après les données mémorisées et basées sur des calculs ou des expériences de chargement précédents, la diminution de poids de la trémie devrait être linéaire pour assurer un débit constant correspondant au débit de consigne Qc. Toutefois, comme le montre l'évolution des deux courbes, à partir d'un certain moment, la différence entre le poids et la matière qui se trouve réellement dans la trémie et celui de la matière qui devrait encore s'y trouver pour respecter le débit constant Qc devient de plus en plus grande et la trémie ne sera vide que bien au-delà du temps imposé T.As can be seen, the horizontal evolution of the flow rate of each of the curves P, and P c represents the phase of opening of the metering valve. When the latter has reached its open position corresponding to the nominal flow rate Q c calculated from the stored data and based on previous calculations or loading experiments, the reduction in weight of the hopper should be linear to ensure constant flow corresponding to the set flow Q c . However, as the evolution of the two curves shows, from a certain moment, the difference between the weight and the material which is actually in the hopper and that of the material which should still be there to respect the constant flow Q c becomes larger and larger and the hopper will not be empty until well beyond the imposed time T.

Comme expliqué ci-dessus, des manoeuvres de correction de la position de clapet pour tenter de compenser l'écart entre les courbes P, et Pc entraînent la situation de la figure 2 dans laquelle le débit réel oscille autour de la valeur de consigne car le clapet est toujours déplacé trop loin, quel que soit le sens de son déplacement.As explained above, maneuvers for correcting the valve position in an attempt to compensate for the difference between the curves P, and Pc lead to the situation in FIG. 2 in which the actual flow rate oscillates around the set value because the valve is always moved too far, regardless of the direction of its movement.

Par contre, en manoeuvrant conformément à la présente invention, c'est-à-dire en effectuant les corrections de la position du clapet seulement dans le sens de son ouverture, on arrive à linéariser la courbe P, et la confondre avec la courbe Pc pour respecter le débit de consigne, comme le montre la figure 3.On the other hand, by maneuvering in accordance with the present invention, that is to say by effecting the corrections of the position of the valve only in the direction of its opening, we manage to linearize the curve P, and confuse it with the curve P c to comply with the set flow rate, as shown in Figure 3.

Si en manoeuvrant conformément à la présente invention, l'ouverture du clapet était trop grande, c'est-à-dire que le débit mesuré était supérieur au débit de consigne, on ne bouge pas le clapet, car sur base des connaissances de la figure 1, on sait que le débit va nécessairement diminuer sans modifier la position du clapet.If when operating in accordance with the present invention, the opening of the valve was too large, that is to say that the measured flow rate was greater than the set flow rate, the valve is not moved, because based on knowledge of the Figure 1, we know that the flow will necessarily decrease without changing the position of the valve.

On va maintenant décrire en référence à la figure 4, un mode d'exécution avantageux pour la réalisation de ce procédé de correction de la position du clapet. Cette figure montre la tête d'un four 10 dans laquelle se trouve une goulotte 12 animée par un dispositif d'entraînement 14 pour la faire tourner autour de l'axe du four et ajuster son angle de déversement. Une charpente 16 portée par le four 10 supporte par l'intermédiaire d'une série de pesons 20 une trémie 18. Ces pesons fournissent constamment des indications sur le poids de la trémie 18 et, par conséquent, sur son contenu. L'orifice d'écoulement de cette trémie 18 est contrôlé par un clapet de dosage 22 qui peut être composé de deux registres à déplacement symétrique autour de l'axe du four. Ce clapet de dosage 22 est actionné par un cylindre hydraulique 24, tandis que la position réelle du clapet est constamment déterminée par un détecteur de position 26.We will now describe with reference to Figure 4, an advantageous embodiment for carrying out this method of correcting the position of the valve. This figure shows the head of an oven 10 in which there is a chute 12 driven by a drive device 14 to rotate it around the axis of the oven and adjust its angle of discharge. A frame 16 carried by the oven 10 supports, via a series of load cells 20, a hopper 18. These load cells constantly provide information on the weight of the hopper 18 and, consequently, on its content. The flow orifice of this hopper 18 is controlled by a metering valve 22 which can be composed of two registers with symmetrical movement around the axis of the oven. This metering valve 22 is actuated by a hydraulic cylinder 24, while the actual position of the valve is constantly determined by a position detector 26.

Sur la figure, on n'a représenté qu'une seule trémie de chargement centrale 18. Il est toutefois évident que l'invention s'applique également à d'autres installations comprenant deux ou plusieurs trémies de chargement.In the figure, only one central loading hopper 18 has been shown. It is however obvious that the invention also applies to other installations comprising two or more loading hoppers.

Le cylindre hydraulique 24 commandant la position du clapet de dosage 22 est actionné par une vanne hydraulique 28 à action proportionnelle qui reçoit l'huile sous pression d'une centrale hydraulique 30. Le circuit de commande comporte également un ordinateur 32 pour effectuer les opérations de calcul et mémoriser toutes les informations nécessaires. Les informations de cet ordinateur 32 sont transmises vers une unité de contrôle 34 qui commande la vanne hydraulique 28 pour régler le débit de l'huile, cest-à-dire la vitesse de manoeuvre du cylindre hydraulique 24 et du clapet 22.The hydraulic cylinder 24 controlling the position of the metering valve 22 is actuated by a hydraulic valve 28 with proportional action which receives the oil under pressure from a hydraulic unit 30. The control circuit also includes a computer 32 for carrying out the operations of calculation and memorizing all the necessary information. The information from this computer 32 is transmitted to a control unit 34 which controls the hydraulic valve 28 to regulate the oil flow, that is to say the operating speed of the hydraulic cylinder 24 and of the valve 22.

L'ordinateur 32 reçoit en permanence les informations P, et S, représentant respectivement le poids réel du contenu de la trémie 18 et la position réelle du clapet de dosage 22. Il réçoit, par ailleurs, des informations de consigne par le programme de chargement, notamment le temps T qu'on s'impose pour l'écoulement du contenu de la trémie 18 en fonction du programme de chargement et/ou de la distribution de la matière. Dans l'ordinateur 32 sont mémorisées les informations nécessaires à la commande, tels que différents paramètres relatifs à la nature de la matière de chargement, la position du clapet pour assurer un débit déterminé d'un matériau déterminé etc. Ces informations mémorisées résultent principalement de mises à jour successives basées sur les connaissances obtenues par des chargements précédents. C'est sur base de ces informations que l'ordinateur calcule et donne des informations de consigne à l'unité de contrôle 34 pour la manoeuvre du clapet 22. Ainsi, par exemple, sachant le temps T imposé pour l'écoulement du contenu de la trémie 18 et connaissant le poids de celui-ci et les paramètres relatifs à la nature du matériau, notamment sa granulométrie et éventuellement d'autres paramètres influençant la vitesse d'écoulement, l'ordinateur détermine le débit de consigne Qc et à partir de celui-ci la position d'ouverture initiale du clapet 22. L'unité de contrôle 34 commande, sur base des informations de consigne reçues de l'ordinateur 32, la vanne hydraulique 28 qui actionne le cylindre 24 jusqu'à ce que la vanne 22 occupe la position d'ouverture de consigne. Cette manoeuvre est contrôlée par le détecteur 26 qui fournit les informations concernant la position instantanée du clapet à l'unité de contrôle qui arrête le mouvement d'ouverture du clapet 22 lorsque la différence AS entre la position réelle S, et la position de consigne Sc est approximativement égale à zéro. A partir de ce moment, cest-à-dire lorsque le clapet 22 occupe sa position d'ouverture de consigne, l'ordinateur détermine à intervalles prédéterminés, par exemple toutes les trois à quatre secondes, l'évolution de la diminution du poids de la trémie 18. Trois cas différents peuvent dès lors se présenter:

  • 1 ) Si le débit réel Qr, c'est-à-dire la diminution de poids Pr par unité de temps est égale au débit de consigne Qc ou est différent de celui-ci d'une quantité négligeable dont la valeur a été fixée arbitrairement au préalable, le clapet 22 est maintenu dans sa position d'ouverture initiale.
  • 2) Si le débit réel Qr est supérieur au débit de consigne Qc, c'est-à-dire que la position S, du clapet est trop grande et que AS = Sc - Sr est négatif, aucune correction de la position du clapet n'est effectuée sachant d'après les renseignements de la figure 1 que le débit Q, va diminuer automatiquement sans modification de la position du clapet 22 pour se rapprocher du débit de consigne Qc. Il est néanmoins possible de prévoir comme mesure de prévoyance, par exemple en cas de faute de programmation, que si AS dépasse exceptionellement une limite supérieure, que le clapet soit automatiquement fermé d'une grandeur correspondant à cette limite prédéterminée.
  • 3) Si le débit réel Q, devient inférieur au débit de consigne Qc, sela signifie que la position de consigne Sc précédente du clapet 22 était en fait trop petite et l'on procède dès lors à une correction de la position du clapet. A cet effet, l'ordinateur calcule les positions du clapet correspondant respectivement au débit de consigne Qc et au débit réel Qr et détermine la différence AS entre ces deux positions. L'unité de contrôle 34 commande dès lors à travers la vanne hydraulique 28 l'ouverture du clapet 22 d'une valeur égale à AS. Cette correction est répétée chaque fois qu'il devient nécessaire, cest-à-dire chaque fois que le débit réel s'écarte du débit de consigne d'une valeur prédéterminée. Ces positions de consigne successivement corrigées du clapet 22 sont mémorisées dans l'ordinateur 32, de sorte que le chargement ultérieur effectué dans des conditions comparables ne nécessitent plus de corrections ou des corrections de moins en moins fréquentes.
The computer 32 permanently receives the information P, and S, representing respectively the actual weight of the content of the hopper 18 and the actual position of the metering valve 22. It also receives setpoint information by the loading program , in particular the time T that is imposed for the flow of the content of the hopper 18 according to the loading program and / or the distribution of the material. In the computer 32 are stored the information necessary for the control, such as various parameters relating to the nature of the loading material, the position of the valve to ensure a determined flow rate of a determined material etc. This stored information mainly results from successive updates based on the knowledge obtained by previous loadings. It is on the basis of this information that the computer calculates and gives setpoint information to the control unit 34 for the operation of the valve 22. Thus, for example, knowing the time T imposed for the flow of the contents of the hopper 18 and knowing the weight of the latter and the parameters relating to the nature of the material, in particular its particle size and possibly other parameters influencing the flow speed, the computer determines the reference flow rate Q c and from from this the initial opening position of the valve 22. The control unit 34 controls, on the basis of setpoint information received from the computer 32, the hydraulic valve 28 which actuates the cylinder 24 until the valve 22 occupies the set point opening position. This maneuver is controlled by the detector 26 which transfers the information concerning the instantaneous position of the valve to the control unit which stops the opening movement of the valve 22 when the difference AS between the actual position S and the reference position S c is approximately equal to zero. From this moment, that is to say when the valve 22 occupies its set point opening position, the computer determines at predetermined intervals, for example every three to four seconds, the evolution of the reduction in weight of hopper 18. Three different cases can therefore arise:
  • 1) If the actual flow rate Q r , i.e. the reduction in weight P r per unit of time, is equal to or different from the target flow rate Q c by a negligible quantity whose value a been fixed arbitrarily beforehand, the valve 22 is kept in its initial opening position.
  • 2) If the actual flow Q r is greater than the set flow Q c , that is to say that the position S, of the valve is too large and that AS = S c - S r is negative, no correction of the valve position is performed knowing from the information in Figure 1 that the flow Q, will decrease automatically without changing the position of the valve 22 to approach the set flow Q c . It is nevertheless possible to provide as a provident measure, for example in the event of a programming fault, that if AS exceptionally exceeds an upper limit, that the valve is automatically closed by a quantity corresponding to this predetermined limit.
  • 3) If the actual flow rate Q, becomes lower than the setpoint flow rate Q c , sela means that the previous setpoint position S c of the valve 22 was in fact too small and a correction is therefore made of the valve position . To this end, the computer calculates the positions of the valve corresponding respectively to the reference flow Q c and to the actual flow Q r and determines the difference AS between these two positions. The control unit 34 therefore controls through the hydraulic valve 28 the opening of the valve 22 with a value equal to AS. This correction is repeated each time it becomes necessary, that is to say each time the actual flow deviates from the set flow by a predetermined value. These successively corrected reference positions of the valve 22 are stored in the computer 32, so that the subsequent loading carried out under comparable conditions no longer requires corrections or less and less frequent corrections.

Suivant un mode de mise en oeuvre avantageux de l'invention, le débit d'huile est reglé par la vanne 28 sur ordre de l'unité de contrôle 34 en fonction de la grandeur AS, c'est-à-dire que le clapet 28 est déplacé plus vite lorsque AS est grand, et inversement, est déplacé de plus en plus lentement au fur et à mesure que AS diminue. Il est même préférable d'arrêter le clapet lorsque AS atteint une limite inférieure prédéterminée pour être certain d'éviter que le clapet ne dépasse sa position de consigne et risquer éventuellement ainsi de se retrouver dans la situation de la figure 2.According to an advantageous embodiment of the invention, the oil flow rate is adjusted by the valve 28 on the order of the control unit 34 as a function of the quantity AS, that is to say that the valve 28 is moved faster when AS is large, and conversely, is moved more and more slowly as AS decreases. It is even preferable to stop the valve when AS reaches a predetermined lower limit to be certain to avoid that the valve does not exceed its set position and possibly risk thus finding itself in the situation of FIG. 2.

Il reste finalement à souligner que le hardware décrit en référence à la figure 4 pour la mise en oeuvre du procédé n'a été montré qu'à titre d'illustration et qu'il est possible de remplacer certains éléments par d'autres ayant les mêmes fonctions. Par exemple, le circuit de commande hydraulique du clapet de réglage pourrait être remplacé par un circuit pneumatique ou un réseau électrique, la vanne à action proportionnelle 28 étant remplacée respectivement par une servo-vanne ou un circuit à thyristor.It finally remains to emphasize that the hardware described with reference to FIG. 4 for the implementation of the method has only been shown by way of illustration and that it is possible to replace certain elements with others having the same functions. For example, the hydraulic control circuit of the regulating valve could be replaced by a pneumatic circuit or an electrical network, the proportional action valve 28 being replaced respectively by a servo valve or a thyristor circuit.

Claims (4)

1. Process for controlling the charging of a shaft furnace, comprising a rotary or oscillating distribution spout for distribution the material over the charging surface of the furnace, one or more hoppers for the storage of the material above the furnace, each provided with a dosing valve serving to regulate the flow of charging material from the hopper to the spout, and a weighing system to determine the contents of the hoppers, which process determines, by calculation or by experiment, the extent to which the valve must be initially open for the contents of the hopper to flow out within a given period, and memorizes for different types of material and different charging condition the theoretical curves of a given constant flow and of the corresponding position of the dosing valve required to ensure the outflow within the given period, these curves indicating at each moment the reference flow Qc and the position of the valve, the real flow Qr being determined at given intervals by measuring the reduction of weight AP in the contents of the hopper per unit time At and comparing the real flow Qr with the reference flow Qc, characterized by the fact that the dosing valve is opened in accordance with an amplitude AS which is equal to the difference between the valve position corresponding to the reference flow Qc and that corresponding to the real flow Qr whenever the real flow Qr is below the reference flow Qc and held in position when the real flow Qr is above the reference flow Qc.
2. Process in accordance with claim 1, wherein the initial opening of the valve is selected to ensure that the resulting flow corresponds to the calculated reference flow Qc.
3. Process in accordance with either of claims 1 or 2, wherein the speed at which the valve acts is proportional to the difference AS of the necessary valve displacement.
4. Process in accordance with claim 3, wherein the valve displacement speed becomes zero when the difference AS reaches a predetermined minimum.
EP86105644A 1985-05-10 1986-04-23 Method for controlling the charging of a shaft furnace Expired EP0204935B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT86105644T ATE41679T1 (en) 1985-05-10 1986-04-23 PROCEDURE FOR CONTROLLING THE LOADING OF A TUBE FURNACE.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
LU85892A LU85892A1 (en) 1985-05-10 1985-05-10 METHOD FOR CONTROLLING THE LOADING OF A TANK OVEN
LU85892 1985-05-10

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EP0204935A1 EP0204935A1 (en) 1986-12-17
EP0204935B1 true EP0204935B1 (en) 1989-03-22

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US (1) US4714396A (en)
EP (1) EP0204935B1 (en)
JP (1) JPH0776372B2 (en)
KR (1) KR930009386B1 (en)
CN (1) CN1006554B (en)
AT (1) ATE41679T1 (en)
AU (1) AU574574B2 (en)
BR (1) BR8602270A (en)
CA (1) CA1269831A (en)
CZ (1) CZ320186A3 (en)
DE (1) DE3662533D1 (en)
ES (1) ES8703618A1 (en)
IN (2) IN165912B (en)
LU (1) LU85892A1 (en)
SU (1) SU1493112A3 (en)
ZA (1) ZA863206B (en)

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Also Published As

Publication number Publication date
EP0204935A1 (en) 1986-12-17
ATE41679T1 (en) 1989-04-15
ZA863206B (en) 1987-02-25
IN167117B (en) 1990-09-01
AU574574B2 (en) 1988-07-07
IN165912B (en) 1990-02-10
CN1006554B (en) 1990-01-24
JPS61266512A (en) 1986-11-26
SU1493112A3 (en) 1989-07-07
CN86103226A (en) 1986-11-05
BR8602270A (en) 1987-01-21
CZ320186A3 (en) 1994-01-19
AU5687486A (en) 1986-11-20
ES554736A0 (en) 1987-03-01
DE3662533D1 (en) 1989-04-27
JPH0776372B2 (en) 1995-08-16
KR930009386B1 (en) 1993-10-02
KR860009133A (en) 1986-12-20
LU85892A1 (en) 1986-12-05
CA1269831A (en) 1990-06-05
ES8703618A1 (en) 1987-03-01
US4714396A (en) 1987-12-22

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