EP0062770B1 - Shaft furnace charging apparatus - Google Patents

Abstract

The delivery of charge material to the hearth of a pressurized blast furnace under the influence of gravity is accomplished without the necessity of changing the direction of material flow at a point exterior of the furnace. The rate of flow of the charge material, which moves in a vertical stream, is controlled by a metering device including a pair of overlapping register elements which define a variable size aperture which remains generally symmetrical with respect to the stream axis.

Description

The present invention relates to a loading installation of a shaft furnace comprising a distribution device with a rotary or oscillating chute, at least one storage enclosure mounted above this chute, and a metering and closing member for adjusting the flow rate of the material to be put in from this enclosure towards the chute.

Until now, the flow rate of the material to be charged flowing from the storage enclosure to the chute has been controlled by a metering device, generally of the type described in patent FR-A-2 175 452 and provided for in the oblique passage connecting the bottom of this enclosure to a vertical supply channel above the chute.

This oblique passage is at the origin of a problem of distribution of the material in the oven and which is described in detail in patent LU-A-82 840. We have tried to solve this problem in various ways, in particular by providing pallets. guide which are the subject of the aforementioned Luxembourg patent, or a kind of tubular plug, as proposed in patent FR-A-2 317 360. All these systems have the common aim of correcting the flow and fall trajectory of the material to bake so that it falls vertically and symmetrically on the chute. All these systems for rectifying the fall trajectory obviously do not have the same result as that which can be envisaged when the storage enclosure, and its flow orifice, are on the vertical axis and allow a vertical and central fall of the material to put in the chute.

Unfortunately, until now, it was not possible to place the storage enclosure in the axis of the oven, and this for two essential and obvious reasons. The first reason is that the majority of chute loading facilities have two juxtaposed storage enclosures operating alternately. However, it is not possible to have two juxtaposed enclosures, both in the axis of the oven. The second reason is due to the fact that the metering devices currently used can only operate by penetrating a current flowing in an oblique direction. Consequently, even in the hypothesis of a single storage enclosure, as for example proposed in patent Fr-AI-2 443 653, it is necessary to offset the storage enclosure in order to have the inclined section necessary for operation. of the dosing organ.

The object of the present invention is to provide a new installation for loading a shaft furnace with an axial arrangement of the storage enclosure, as well as a new metering member allowing this arrangement, that is to say capable of adjust the flow rate of a vertically flowing current.

To achieve this objective, the installation proposed by the patent application has the characteristics of claim 1.

According to a preferred embodiment, the metering member is located in a valve cage and this metering member consists of two caps-shaped registers each having a substantially V-shaped cutout and carried by shafts arranged diametrically and there is provided a drive mechanism for pivoting the two registers in synchronism and in opposite directions, so that the two cutouts combine their effects to determine and vary the flow section so that it constantly evolves symmetrically around the central axis.

According to a first embodiment, said storage enclosure is an airlock comprising an upper sealing valve and a lower sealing valve, both in the shape of a cap, the lower valve also being provided in the valve cage, said enclosure being surmounted by a holding hopper also mounted on the vertical axis and provided with a material retaining valve.

According to another embodiment, said storage enclosure is surmounted by an airlock equipped with an upper sealing valve and a lower sealing valve, both in the shape of a cap, as well as a material retention.

The check valve fitted, in the two embodiments, the bottom of the upper tank, whether the latter acts as a holding hopper or airlock, will preferably also be in the form of a register of single or double spherical shape, analogous to the metering member, except that it does not need to include a cutout. This check valve, as well as the section of the opening with which it is associated, will preferably be as large as possible. In fact, by providing a large flow opening at the bottom of this tank, it is ensured that the transfer of its contents to the storage enclosure takes place, if not instantaneously, at least in a few seconds. By accelerating in this way the filling phase of the storage enclosure, the total duration of a loading cycle will not be much longer than that of installations with two juxtaposed airlocks working alternately.

According to another particular feature of the invention, both the registers of the metering members or the retaining valves and the sealing valves are in the form of a spherical cap and the pivot axis of the sealing valves is located approximately at the same level than the pivot axis of the registers of the metering or retaining members with which they are associated. This allows the sealing valves to be brought closer to the registers of the metering or retaining members, in comparison with conventional pivoting valves which require more space for operate. This design therefore clearly allows a total reduction in height.

Another advantage of this design of valves is that these can be combined in valve cages with reduced volume and which are removable as a unit, by lateral translation, without dismantling the valves and in a single operation.

The registers are supported on one side by a single shaft and on the opposite side, by two shafts arranged one coaxially with respect to the other and housed in bearings to actuate, by pivoting about their longitudinal axes respectively, both registers.

The register drive mechanism consists, according to a first embodiment, of a sliding fork, movable in a direction perpendicular to the pivot axis of the registers, and provided with two rows of gears respectively forming rack with two toothed sectors respectively integral with the two coaxial shafts for actuating the registers.

The drive mechanism comprises, according to a second embodiment, a rotary shaft arranged perpendicularly to the pivot axis of the registers and driven by a motor, by means of a worm and a wheel endless screw, and carrying two bevel gears arranged on either side of the pivot axis and cooperating respectively with two sectors with conical teeth respectively integral with each of the coaxial shafts to actuate the registers.

• La figure 1 représente schématiquement une coupe verticale à travers un premier mode de réalisation d'une installation de chargement selon l'invention.
• La figure 2 représente une vue analogue d'un deuxième mode de réalisation,
• La figure 3 montre schématiquement une vue d'une coupe horizontale à travers la cage à clapets avec un organe de dosage et un clapet d'étanchéité,
• La figure 4 montre schématiquement une vue suivant le plan de coupe vertical IV-IV sur la figure 3,
• La figure 5 montre schématiquement une coupe verticale à travers la tubulure d'écoulement lorsque les registres occupent une position fermée,
• La figure 6 montre les registres en position de fermeture par une vue en coupe horizontale,
• La figure 7 est une vue analogue à celle de la figure 5 en position semi-ouverte des registres,
• La figure 8 montre une vue correspondant à celle de la figure 6, lorsque les registres occupent la position de la figure 7,
• La figure 9 est une vue latérale d'un premier mode de réalisation d'un mécanisme d'entraînement des registres de dosage,
• La figure 10 est une vue suivant le plan de coupe vertical X-X de la figure 9,
• La figure 11 est une vue suivant le plan de coupe XI-XI de la figure 9,
• La figure 12 est une vue axiale, partiellement en coupe d'un deuxième mode de réalisation d'un mécanisme d'entraînement des registres,
• La figure 13 est une vue suivant le plan de coupe horizontal XIII-XIII de la figure 12,
• La figure 14 montre schématiquement, en coupe verticale, un premier mode de réalisation d'un mécanisme pour actionner les clapets d'étanchéité,
• La figure 15 est une vue analogue illustrant un deuxième mode de réalisation d'un mécanisme pour actionner les clapets d'étanchéité et,
• La figure 16 est une vue analogue illustrant un troisième mode de réalisation d'un mécanisme pour actionner les clapets d'étanchéité.

Other particularities and characteristics will emerge from the detailed description below, given by way of illustration, with reference to several embodiments, and with reference to the appended figures, in which:

• FIG. 1 schematically represents a vertical section through a first embodiment of a loading installation according to the invention.
• FIG. 2 represents a similar view of a second embodiment,
• FIG. 3 schematically shows a view of a horizontal section through the valve cage with a metering member and a sealing valve,
• FIG. 4 schematically shows a view along the vertical section plane IV-IV in FIG. 3,
• FIG. 5 schematically shows a vertical section through the flow pipe when the registers occupy a closed position,
• FIG. 6 shows the registers in the closed position by a horizontal section view,
• FIG. 7 is a view similar to that of FIG. 5 in the semi-open position of the registers,
• FIG. 8 shows a view corresponding to that of FIG. 6, when the registers occupy the position of FIG. 7,
• FIG. 9 is a side view of a first embodiment of a mechanism for driving the dosing registers,
• FIG. 10 is a view along the vertical section plane XX of FIG. 9,
• FIG. 11 is a view along the section plane XI-XI of FIG. 9,
• FIG. 12 is an axial view, partially in section of a second embodiment of a drive mechanism for the registers,
• FIG. 13 is a view along the horizontal section plane XIII-XIII of FIG. 12,
• FIG. 14 schematically shows, in vertical section, a first embodiment of a mechanism for actuating the sealing valves,
• FIG. 15 is a similar view illustrating a second embodiment of a mechanism for actuating the sealing valves and,
• Figure 16 is a similar view illustrating a third embodiment of a mechanism for actuating the sealing valves.

Figures 1 and 2 schematically show the upper part of a shaft furnace 20 in which is suspended a rotary or oscillating chute 22 to ensure the distribution of the loading material discharged into the furnace. This chute 22 is actuated by an appropriate mechanism housed, in the embodiment shown, in a housing designated by 24 and intended to communicate to the chute 22 the desired movement. A central channel 26 guides the material to be put into the chute 22.

According to the first embodiment illustrated in Figure 1, a storage enclosure 28, designed as an airlock and provided for this purpose with a lower sealing valve 36 and an upper sealing valve 44, is mounted above the oven 20. Between the airlock 28 and the oven there is a valve cage 30 containing, in addition to the lower sealing valve 36, a metering member 34 intended to regulate the flow of the loading material through a drain pipe 38 forming the bottom of the airlock 28.

According to one of the features of the invention, the airlock 28 is mounted around the central axis 0 of the furnace, as is the flow pipe 38 and the metering member 34. The material to be put in therefore falls , depending on the position of the metering member 34, directly from the airlock 28 and this, symmetrically with respect to the axis 0, on the chute 22. The flow of material from the airlock 28 is therefore always the same manner and the problems of asymmetry of distribution as a result of an oblique and offset movement of the loading material no longer exist.

The metering, that is to say the control of the metering member 34 to regulate the flow, is carried out according to the loading requirements and according to the content in the airlock 28. For this purpose, this airlock 28 is weighed permanently or periodically to determine its content. This is the reason why the valve cage includes a peripheral compensator 32 to separate the airlock 28 from the oven 20. The weighing is carried out. by means of several, preferably three load cells 40 on which the airlock rests, the load cells being, in turn, carried by fixed uprights 42 forming part of the frame or superstructure.

It should be noted that during the emptying phase of the airlock 28, that is to say when the lower valves are open and that the upper sealing valve 44 is closed, and that the airlock 28 is approximately under the same pressure as that prevailing inside the oven, this airlock undergoes, as a result of this pressure, an upward force proportional to the cross section of the compensator 32. To reduce the influence of this upward force on the measurements provided by the load cells 40 and , if necessary, to avoid negative measurements, these load cells are prestressed with a value corresponding to or greater than this upward force.

Above the airlock 28 is a waiting hopper 46 intended to be filled while the airlock 28 is emptied. A check valve 48 provided at the bottom of a flow pipe 52 of this hopper makes it possible to establish communication between this hopper 46 and the airlock 28 when the sealing valve 44 is open. To ensure the fastest possible transfer of the loading material from the holding hopper 46 to the airlock 28, the section of the flow pipe 52 is preferably as large as possible. To prevent the weight of the hopper 46 from intervening in the weighing of the airlock 28, there is a total separation, for example, at the check valve 48, between the hopper 46 and the airlock 28. The hopper 46 rests on beams 50 forming part of the superstructure not shown.

The different phases constituting a loading cycle, as well as the sequence of these different phases are explained in detail in patent application FR-A-2 443 653 also describing a loading installation with a single airlock surmounted by a hopper d 'waiting.

In the embodiment illustrated in FIG. 2, the upper reservoir designed in the form of an airlock 58 and provided, for this purpose, with an upper sealing valve 62 and a lower sealing valve 64, is mounted at the above the storage enclosure 60 which, according to the present invention, is also arranged along the axis 0 of the furnace and which is provided with a flow pipe 66. The flow adjustment by this pipe 66 is produced using a metering member 68 identical to the metering member 34 of the previous embodiment and also mounted in a valve cage designated by the reference 80.

As in the previous embodiment, the storage enclosure 60 is also designed in the form of a weighing hopper and rests, for this purpose, on several fixed load cells 72 supported by the superstructure 74. To allow the weighing of the enclosure 60 , this is isolated from the furnace by a compensator 70, and from the airlock 58 by a second compensator 76. If the cross section of the compensator 76 is equal to that of the compensator 70, the upward force due to the back pressure in the furnace has no effect on the results of the weighing and, therefore, it is not necessary to pre-stress the load cells 72, the metering member 68 not being tight against the back pressure.

It should be noted that both in FIG. 1 and in FIG. 2, only one load cell 40 and 72 respectively has been presented, and that, if three load cells are used, these are arranged at 120 degree intervals around the enclosure.

The airlock 58 rests on the superstructure schematically designated by the beams 84 The communication between the airlock 58 and the enclosure 60 is carried out, by means of a check valve 78, when the sealing valve 64 is open. This check valve 78 may be analogous to the metering member 68, that is to say be composed of two complementary registers, without cutouts, since there is no metering function. This has the advantage of a symmetrical and vertical flow of the airlock 58. It is, of course, possible to design this check valve 78 in the form of a simple valve, as shown by 48, in FIG. 1. Vice -versa, the latter can be designed as a double valve like the valve 78 of Figure 2.

In the second embodiment, the upper valves 64, 78 are located in a valve cage 82. This cage is removable and can be released laterally, as a unit, with the valves. The same is true of the lower valve cages 30 and 80 which are also removable and can be removed laterally with the valves and the flow pipes 38 and 66.

These valve cages will moreover be described in more detail with reference to FIGS. 3 and 4.

The characteristic of the invention of having the storage enclosure 28 or 60 on the axis 0 of the oven has been shown with reference to two different embodiments, since these each have very specific advantages. However, before mentioning these specific advantages of each of the embodiments, it should be noted that they have common advantages over the state of the art, in addition to that of solving the problem of central and symmetrical discharge by in relation to axis 0. In fact, in the two embodiments, it was possible to eliminate the inclined plane necessary in existing installations formed by what is called “funnel of flow above the central channel 26 In addition, the axial arrangement of the storage enclosure 28, 60 allows the elimination of the moment inevitably exerted on this enclosure by the upward force of the back pressure, when this enclosure is off-axis with respect to the central axis 0.

As regards the particular advantages of each of the embodiments compared to the other, it should be mentioned, as regards the embodiment of FIG. 1, that this allows a lower construction than that of FIG. 2. This is due to the fact that the waiting hopper 46 is open and that the height necessary in the embodiment of FIG. 2 is gained to actuate the flap valve. higher density 62. The wide opening of this hopper 46 also facilitates its filling by skips or by conveyor.

The particular advantage of the embodiment of Figure 2 has already been mentioned. This is the possibility of eliminating the upward force on the enclosure 60 when the sections of the compensators 70 and 76 are equal and, consequently, the elimination of the measures necessary to eliminate the false measurements which result therefrom.

Another advantage common to the two embodiments is obtained by harmonizing the shapes of the sealing valves and of the metering members. Indeed, as the shapes of the registers forming the metering members correspond to the shapes of the sealing valves and that the axes of rotation of one and the other are approximately at the same level, they allow a very compact construction of the valve cages.

Figures 3 and 4 show a more detailed view of the valve cage 30. The metering member 34 consists of two registers 86, 88 with concentric spherical curvature whose center of curvature is located at the intersection of their axis of pivoting, represented by X and the central axis of the furnace 0. These two registers 86, 88 are carried on one side by the same pivoting shaft 90 which is sealed in a bearing in the wall 92 of the cage 30. On the side diametrically opposite to the shaft 90, the upper register 86 is carried by a shaft 94 passing coaxially through a hollow shaft 96 carrying the lower register 88. The two shafts 94 and 96 can rotate one relative to the 'other and relative to the wall 92 of the cage and there are provided suitable bearings to allow these rotations, as well as seals, known per se, to provide the necessary seal.

It should be noted that the single pivot shaft 90 supporting on one side the two registers 86, 88 is not visible in FIG. 4, given that this is not a diametrical section, but a section along the broken line IV-IV, in order to be able to illustrate in FIG. 4 the sealing valve 36. This valve 36 is applied, in the closed position against a seat 98 fixed to the lower part of an intermediate tube 100 surrounding the flow pipe 38. This valve 36 is also in the form of a spherical cap, the center of curvature of which is also located at the intersection of the axes 0 and X, the axis of rotation Y of the valve 36 however making a predetermined angle with l 'axis of rotation X of the member 34. This angle between the axes X and Y results from the need to provide the space necessary for the movement of the different parts and to avoid striking the shaft 90.

The sealing valve 36 is supported in the wall 92 of the cage 30 by support and drive means, described in more detail below, to pivot the valve 36 around the Y axis, that is that is, to bring it from the closed position in FIG. 4 to a garage position in which it is raised in the annular space formed between the intermediate tube 100 and the wall 92 of the cage 30. The registers 86 and 88 are also driven by suitable means, described in more detail below, to turn them in opposite directions and in synchronism around the X axis and to bring them from the closed position according to FIG. 4 to an open position in which they occupy the annular space between the two pipes 38 and 100 and vice versa. The operation of these registers 86 and 88 will moreover be the subject of the description which follows, with reference to FIGS. 5 to 8.

Figures 5 and 6 first show the two registers 86 and 88 in the closed position. As can be seen, in particular in FIG. 6, the two registers 86, 88 have the shape of a spherical cap in each of which is provided a cutout 86a and 88a respectively. These cutouts 86a and 88a are substantially in the shape of a "V" and are symmetrical with respect to the same diametral plane. For each of the two registers 86 and 88, these cut-outs must be located on the side which constitutes the leading side when the register enters the stream of material flowing through the tubing 38 and must not be deeper. as the radius of the tubing 38, this in order to allow the complete closure of the latter. In fact, as shown in FIGS. 5 and 6, the cutout 86a of the register 86 is completely doubled by the solid part of the register 88, while the cutout 88a of the latter is completely covered by the solid part of the register 86. For the desired effect to be achieved, it suffices that, in the closed position of the valves, each of these cutouts diverges from the central region towards the edge of the valve. On the other hand, it is not necessary that the two sides which delimit each of these cutouts extend, seen in plan, in a straight line. They can, for example, be slightly curved relative to the opening of the cutout, this in order to determine the geometric shape of the flow opening during opening.

The evolution of this opening is shown in FIGS. 7 and 8. When the two registers 86 and 88 are pivoted in opposite directions according to the arrows in FIG. 7, the solid parts of each of the registers 86 and 88 move apart. one from the other, while the cutouts 86a and 88a intersect to determine the opening section which goes from the complete closure according to FIG. 6 to a total opening, not shown, progressively passing through intermediate openings, one of them being represented by the hatched surface 102 in the form of a tile in FIG. 8. The particularity of these two registers is therefore that they provide an increasing or decreasing opening which remains permanently symmetrical with respect to the axis central 0, like the apertures determined by diaphragms. The central and symmetrical flow is therefore guaranteed by this opening. As already mentioned above, we can influence the geometric shape of the section of this opening for the geometric shape of the sides delimiting one of sections 86a and 88a in the registers. For example, instead of having a square with concave sides, as in FIG. 8, it is possible to obtain, with another shape, cutouts 86a and 88a a square with convex sides, and tending towards a circle.

Figures 9 to 11 schematically show a first embodiment of a mechanism for actuating the two registers symmetrically and in opposite directions. This mechanism is contained in a housing 110 mounted outside the valve cages 30, 80, 82. The essential element of this mechanism is a sliding fork 112 mounted so that it can be moved along its longitudinal axis perpendicular to the trees 94 , 96. The two branches 114 and 116 of this fork each have an inner row of teeth forming a rack respectively with a toothed sector 118 secured to the shaft 94 and a toothed sector 120 secured to the shaft 96. These two sectors 118 and 120 and, consequently, the registers 86 and 88 are rotated synchronously, in opposite directions, in one direction or the other, according to the direction of movement of the fork 112.

To actuate the fork 112, there is shown, by way of example, a third rack consisting of a pinion and a row of teeth provided on the handle 122 of the fork 112. This pinion 124 is integral with a shaft 126 housed in suitable sealed bearings of the housing 110 and driven by a motor not shown by means of a worm gear assembly the worm wheel of which is designated by 128. The reference 130 schematically designates a simulation device and reproducing the movement of the registers for the purpose of monitoring and controlling their operation. It should be noted that the fork 112 can be actuated by other means, such as for example, a hydraulic cylinder, a form of threaded rod, etc.

Figures 12 and 13 show a second embodiment of a mechanism for actuating the two registers 86 and 88. The essential element of this mechanism is a drive shaft 140 carrying two bevel gears 142 and 144 located on both sides. other of the extension of the pivot axis X. The pinion 142 forms a gear with a conical toothed sector 146 secured to the shaft 94, while the pinion 144 forms a gear with another conical toothed sector 148 secured to the shaft 96 These gears 142-146 and 144-148 being arranged on either side of the axis X of pivoting of the shafts 94 and 96, a rotation of the drive shaft 140 in one direction or the other causes always a rotation between opposite directions, of the shafts 94 and 96. The drive shaft 140 is carried by suitable bearings provided in a wall 150 of a housing, while its movement derives from an external electric motor 152 through a reduction system 154 comprising a worm 156 and a worm wheel 158 fixed on the shaft 140.

Sealing between the inside of a valve cage and the outside can be carried out either between this cage and the box containing the mechanism for actuating the dampers, or between this box and the outside in which case this box is located under a pressure approximately equal to that existing in the oven.

FIG. 14 shows a first embodiment for actuating a sealing valve, for example the valve 36. This mechanism essentially comprises a hollow rotary support housed around its axis of rotation Y in a sealed bearing 162 of the wall 92 of the valve cage 30. This support 160 is extended towards the inside of the cage by a yoke 164 comprising a shaft 166 forming a support and pivot axis with an arm 168 whose lower end carries the valve 36 and whose upper end is articulated on a rod 170 undergoing an axial longitudinal movement under the action of an electric, hydraulic or pneumatic motor 172. The support 160 comprises an arm 174 directly connected to a hydraulic cylinder or an endless screw, not shown, for pivoting the support 160 around the Y axis.

The complete opening of the valve 36 consists first of all in disengaging the latter from its seat 98 by actuating the motor 172 which displaces the rod 170 to the left in the figure. This movement allows the valve to pivot, under the influence of the motor and its weight, around the shaft 166 and change from the position shown in solid lines to the position in broken lines. The complete release of the valve 36 consists in turning the assembly formed by the valve 36, the bent arm 168 and the support 160 around the axis Y, by acting on the arm 174 by the jack not shown, to place the valve 36 in a garage position located between the pipe 100 and the wall 92 (see Figure 4). The closing of the valve comprises the same operations, in opposite direction, that is to say the rotation of the support 160 around the axis Y followed by a translation, towards the right in FIG. 14, of the rod 170 by the motor 172 for applying the valve 36 against its seat.

FIG. 15 shows a second embodiment for actuating the sealing valve 36, in which this valve is removable from its mechanism. This essentially comprises a pivoting support 180 in the form of an “L”, one of the branches 180a of which is housed around its axis of rotation in a sealed bearing 162 provided in the wall 92 of the cage. Inside the branch 180a of this support 180 is a hydraulic piston 182 permanently undergoing the action of a helical spring 186 wound around its rod 184 and bearing on an inner rim traversed by this rod. In the other branch 180b of this support 180 is a slide 188 which can slide inside this branch 180b and whose rotation relative to the latter is prevented by keying or a polygonal shape. This slide 188 is connected to the piston rod 184 by a rod 190 articulated both on the slide 188 and on the piston rod 184. The slide 188 is also connected outside the support 180, to an arm 192 carrying the valve 36. The connection between the slide 188 and the arm 192 is removable, which is symbolized by the nut 194, and anti-revolving to avoid relative rotation between the arm 192 and the slide 188.

The support 180 is provided, outside the valve cage with an arm 196 actuated directly, for example by a hydraulic cylinder, not shown to pivot the support 180 with the valve 36 around the axis X. By elsewhere, a rotary connector represented by 198, makes it possible to subject the piston 182 to the action of a hydraulic fluid under pressure to move the piston 182 and the rod 184 against the action of the spring 186, while allowing rotation of the support. 180 around the axis X. The opening of the valve 36 comprises an initial phase consisting in moving this valve 36 away from its seat 98. To this end, the piston 182 is subjected to the action of the pressure of the hydraulic fluid against the action of the spring 186, which moves the rod 184 to the left, until in the position indicated by broken lines. This displacement of the rod 184 allows the sliding of the slide 188 in the branch 180b of the support 180, which allows the valve 36 and the arm 192 to come to occupy the position in broken lines. From this position, the arm 196 can be actuated to rotate the support 180 and the valve 36 around the axis X to bring the latter into the garage position. The closure includes the same phases in reverse order, that is to say that the valve is brought from the garage position to the position illustrated in broken lines by the action of the jack not shown on the arm 196. A from this position, the pressure of the hydraulic fluid on the piston 182 is released, which allows the spring 186 to return the piston 182 to the position indicated in FIG. 15 and to lift, by this movement, the slide 188 and the valve 36 against its seat 98. In order for the system to function, it is of course necessary for the force exerted by the spring 186 to be greater than the force resulting from the weight of the valve 36, of the arm 192 and of the slide 188.

FIG. 16 illustrates a third embodiment of a mechanism for actuating the valve 36. This embodiment is based on the same operating principle as the embodiment of FIG. 15, and consequently comprises similar elements which are represented by the same references as in FIG. 15. A pivoting support 200 in the shape of an "L" is housed, in a sealed manner, in a bearing 162 of the wall 92 and comprises an arm 196 undergoing the action for example of a jack hydraulic, not shown, to turn it around the X axis. In the other branch of this support 200 is a piston 210 which can slide perpendicular to the X axis and undergoes, on the one hand, the action of a spring 202 around its rod 204 and, on the other hand, the action of a hydraulic fluid penetrating through a fitting 198 and an axial pipe 206 in a chamber 208 on the front side of the piston 210. The end of the piston rod 204 is removably connected to arm 192 of the valve pet 36 in the same way as the slide 188 of the embodiment of FIG. 15. Any relative rotation between the arm 192 and the rod 204, on the one hand, and between the rod 204 and the support 200, on the other hand , is prevented by keying or other known means.

The first phase of opening the valve 36 therefore consists of sending hydraulic fluid into the chamber 208 to move the piston 210 against the action of the spring 202 and bring the valve 36 down to the position shown in broken lines. After that, the valve 36 can be pivoted in the garage position by pivoting the support 200 around the axis X. After having brought the valve 36 from the garage position to the position illustrated in broken lines by a reverse rotation of the support 200, a release of the pressure of the hydraulic fluid on the piston 210 allows the spring 202 of the latter to raise the piston and bring the valve against its seat 98 in the position shown in solid lines.

It is obvious that the various mechanisms described above for actuating the registers of the metering member, as well as the sealing valves, have only been shown by way of illustration.

Claims (13)

1. Charging installation for a shaft furnace (20) comprising a distribution apparatus with a rotary or oscillating spout (22), at least one storage enclosure (28, 60) mounted above the said spout (22) and a dosing and closing device (34, 68) serving to regulate the rate at which the furnace charging material is fed from the said enclosure (28, 60) to the spout (22) characterized in that the said enclosure (28, 60) is provided at the bottom with a discharge pipe (38, 66) on the vertical axis (0) of the furnace (20) and in that said discharge pipe (38, 66) is controlled by a dosing device (34, 68) designed to increase and reduce the discharge section of this pipe (38, 66) symmetrically about the central axis (0).

2. Installation in accordance with claim 1, characterized in that said dosing device (34, 68) is mounted in a valve cage (30, 80) and consists of two registers (86, 88) which are of the shape of a spherical cap, each having a substantially V-shaped cut-out portion (86a, 88a), and which are borne by shafts (90, 94, 96) positioned diametrically, and in that a driving mechanism is provided for the purpose of displacing the two registers (86, 88) synchronously and in opposite directions, in such a way that the two cut-out portions (86a, 88a) combine their effects in order to determine and vary the discharge cross section so that it will at all times remain symmetrically around the central axis (0).

3. Installation in accordance with claim 2, characterized in that said enclosure is a chamber (28) comprising an upper sealing valve (44) and a lower sealing valve (36), both of the shape of a spherical cap, the lower valve (36) being likewise situated in the valve cage (30), the said enclosure (28) being surmounted by a stand-by hopper (46) likewise mounted on the vertical axis (0) and provided with a retaining valve (48).

4. Installation in accordance with claim 2, characterized in that the said enclosure (60) is surmounted by a chamber (58) equipped with an upper sealing valve (62) and a lower sealing valve (64), both of the shape of a spherical cap, and also a retaining valve for controlling the discharge of material into the enclosure (60).

5. Installation in accordance with any one of claims 3 or 4, characterized in that the retaining valves (48, 78) also comprise two registers similar to those of the dosing device (34, 68) but without a cut-out portion.

6. Installation in accordance with any one of claims 2 to 5, characterized in that the valve cages (30, 80, 82) can be dismantled by extracting them sideways in the form of a complete block including the sealing valves (36, 64) and the dosing devices (34, 68) or retaining valves (78).

7. Installation in accordance with claim 2, characterized in that the registers are supported on one side by one single shaft (90) and on the other side by two shafts (94, 96) positioned coaxially with each other and accomodated in bearing systems, in order to actuate each of the two registers (86, 88) by pivoting about their respective longitudinal axes (X).

8. Installation in accordance with claim 7, characterized in that the driving mechanism for the registers (86, 88) consists of a sliding fork (112) displaceable in a direction perpendicular to the pivoting axis (X) of the registers (86, 88) and provided with two rows of gearings (114, 116) forming a rack with two toothed sectors (118, 120) integral with the two respective coaxial shafts (94, 96) for the operation of the registers (86, 88).

9. Installation in accordance with claim 7, characterized in that the driving mechanism of the registers comprises a rotary shaft (140) positioned perpendicularly to the pivoting axis (X) of the registers (86, 88) and driven by a motor (152) via an endless screw (156) and a wormwheel (158) and bearing two conical pinions (142, 144) situated on the two sides of the pivoting axis (X) and interacting with two conical toothed sectors (146, 148) integral with the respective coaxial shafts (94, 96) for the operation of the registers (86, 88).

10. Installation in accordance with any one of claims 2 to 6, characterized in that the mechanism for the operation of a sealing valve (36) comprises a hollow rotary support (160) mounted about its rotation axis in a tight bearing system (162) in the wall (92) of the valve cage and prolonged towards the inside of the cage in the form of a link (164) comprising a shaft (166) forming a support and pivoting axis for an arm (168) of which the lower end bears the valve (36) and of which the upper end is articulated to a rod (170) undergoing an axial longitudinal movement under the action of an external motor (172).

11. Installation in accordance with any one of claims 2 to 6, characterized in that the mechanism for actuating a sealing valve (36) comprises a hollow rotary support (180, 200) mounted about its rotation axis in a tight bearing system (162) in the wall (92) of the valve cage and comprising a piston (182, 210) which is exposed on one side to the action of the hydraulic fluid and on the other to the action of the spring (186, 202) and of which the rod (184, 204) is connected to an arm (192) bearing the valve (36) the action of the spring (186, 202) being such that it tends to displace the piston (182, 210) in the direction corresponding to the application of the valve (36) to its seating (98).

12. Installation in accordance with claim 11, characterized in that the arm (192) of the valve (36) is removably affixed to the piston rod (204) by means of an anti-gyratory device in order to prevent any relative rotation from taking place between the valve (36) and the support.

13. Installation in accordance with claim 11, characterized in that the arm (192) of the valve is removably affixed to a slide (188) which is displaceably in the support (180) in a direction perpendicular to the rotation axis (X) of the said support and which is connected by an articulated link (180) to the piston rod (184) and that an anti-gyratory device prevents the arm (192) of the valve from rotating in respect of the support (180).

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