EP0252342B1 - Device for closing a central upper opening of a vessel, and its use in a bunker for a shaft furnace charging installation - Google Patents

Abstract

This invention relates to a device comprising a sealing valve carried by a control arm inside a vessel and cooperating with a seat around an opening. The mechanism for operating the valve comprises a hollow rotary support housed about its axis of rotation X in a leaktight bearing on the wall of the vessel and connected to the other end of the control arm by means of a device permitting axial displacement of the valve in relation to its seat. In order to reduce the space required for the movements of the valve, the support of the valve operating mechanism is mounted in such a manner that its axis of rotation X forms an acute angle with the vertical axis of the opening of the vessel.

Description

The present invention relates to a device for closing an upper central opening of an enclosure comprising a sealing valve in the form of a spherical cap carried by one of the ends of a control arm inside the enclosure and cooperating with a seat around said opening, a mechanism for actuating the valve, this mechanism comprising a rotary hollow support housed around its axis of rotation in a sealed bearing of the wall of the enclosure, and connected to the other end of the control arm by means of a device allowing axial movement of the valve relative to its seat. The invention also relates, by way of application, to a storage hopper of a loading installation of a shaft furnace provided with such a closing device.

An installation for loading a shaft furnace with a closing device of the kind described above is proposed in patent EP0062770. The storage hopper of this patent is provided with upper and lower sample valves as described above and which are shown in detail in particular in FIG. 14 of the aforementioned patent.

The lower valve evolves in a valve cage, outside the enclosure, while the upper valve is always inside the enclosure.

The upper valve therefore entails the disadvantage of reducing the capacity of the enclosure, because when it is open, it is turned around an axis perpendicular to the axis of the hopper to occupy a substantially vertical position. The filling of the hopper must therefore be interrupted before the cone for discharging the loading material touches the valve in its open position, i.e. the capacity of the hopper is reduced by a certain volume which can be qualified as lost, which means that a larger hopper must be provided to introduce, at each cycle, a determined quantity of material into the oven.

The object of the present invention is to provide an improved closing device which allows a significant reduction in the space lost in the upper part of the enclosure by the opening of the valve.

According to a preferred embodiment of the invention, this object is achieved, by a closing device of the kind described in the preamble, which is characterized in that the support of the mechanism for actuating the valve is mounted so that its axis of rotation forms an acute angle with the vertical axis of the enclosure opening.

• La figure 1 montre schématiquement une vue d'ensemble d'une installation de chargement d'un four à cuve;
• la figure 2 montre schématiquement, partiellement en coupe verticale, les détails du dispositif de fermeture de l'ouverture supérieure de la trémie de chargement;
• la figure 3 montre schméatiquement une vue latérale par rapport à la figure 2, illustrant le clapet en position d'ouverture;
• la figure 3a montre schématiquement, en projection horizontale, les positions ouverte et fermée du clapet;
• les figures 4,5 et 5a montrent des vues correspondant respectivement à celles des figures 2, figures 3 et figures 3a pour une trémie de stockage avec une ouverture supérieure plus large;
• la figure 6 montre schématiquement un dispositif de fermeture de l'ouverture supérieure de la trémie, conformément à la présente invention;
• la figure 7 montre une vue analogue à celle de la figure 6, mais avec un clapet en position ouverte;
• la figure 7a montre schématiquement, en projection horizontale, la position ouverte du clapet;
• la figure 8 illustre schématiquement le gain de capacité de la trémie réalisable par le dispositif de fermeture selon la présente invention;
• la figure 9 illustre schématiquement, partiellement en coupe verticale, un mode de réalisation préféré d'une trémie de stockage équipée d'un dispositif de fermeture selon l'invention;
• les figures 10 et 11 illustrent schématiquement le chargement de la trémie montrée sur la figure 9 et
• la figure 11 a montre, en projection horizontale, la position ouverte du clapet de la figure 9.

Other features and characteristics of the invention will emerge from the description of a preferred embodiment, presented below, by way of illustration, with reference to the appended drawings, in which:

• Figure 1 schematically shows an overview of a loading installation of a shaft furnace;
• FIG. 2 schematically shows, partially in vertical section, the details of the device for closing the upper opening of the loading hopper;
• Figure 3 schematically shows a side view with respect to Figure 2, illustrating the valve in the open position;
• FIG. 3a schematically shows, in horizontal projection, the open and closed positions of the valve;
• Figures 4,5 and 5a show views corresponding respectively to those of Figures 2, Figures 3 and Figures 3a for a storage hopper with a larger upper opening;
• FIG. 6 schematically shows a device for closing the upper opening of the hopper, in accordance with the present invention;
• Figure 7 shows a view similar to that of Figure 6, but with a valve in the open position;
• FIG. 7a schematically shows, in horizontal projection, the open position of the valve;
• Figure 8 schematically illustrates the gain in capacity of the hopper achievable by the closure device according to the present invention;
• FIG. 9 schematically illustrates, partially in vertical section, a preferred embodiment of a storage hopper equipped with a closing device according to the invention;
• Figures 10 and 11 schematically illustrate the loading of the hopper shown in Figure 9 and
• FIG. 11 a shows, in horizontal projection, the open position of the valve of FIG. 9.

Figure 1 schematically shows a known loading installation of the kind described in the aforementioned patent EP0062770. This figure shows the upper part of a tank oven 20 in which a chute 22 is suspended to ensure the distribution of the loading material poured into the oven. This chute 22 is actuated by an appropriate mechanism housed, in the embodiment shown, in a chamber defined around a central channel 26 ensuring the guidance of the material to be placed in the chute 22.

In the embodiment shown, a storage enclosure 28, designed in the form of 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 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 flow pipe. 38 forming the bottom of the airlock 28.

In the embodiment shown, the airlock 28 is subject to permanent or periodic weighing 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 actual weighing is carried out by means of several, preferably 3 load cells 40, on which the airlock, the load cells rests. being, in turn, carried by fixed uprights 42 forming part of the frame or superstructure of the oven.

Above the airlock 28 is a waiting hopper 46 which is filled while the airlock 28 is emptied. A check valve 48 provided at the bottom of a flow pipe 52 of this hopper allows blir the 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 waiting hopper 46 to the airlock 28, the section of the passage between the waiting hopper 46 and the airlock 28 is preferably as large as possible and the size of the valve 44 in particular must be designed as a function of the size of this section.

The upper sealing valve 44 is in the form of a spherical cap and cooperates, with a view to establishing the sealing of the airlock 28 with an annular seat 54 turned towards the inside of the airlock 28. FIG. 2 shows the details d 'An embodiment of a mechanism for actuating the valve 44 corresponding to that of Figure 14 of the aforementioned European patent EP0062770. This mechanism essentially comprises a rotary hollow support 60 housed around its axis of rotation X in a sealed bearing 62 of the wall 58 of the enclosure 28. This support 60 is extended towards the inside of the enclosure 28 by a yoke 64 comprising, at its end, a pivot 66 forming a support and pivot axis to a bent arm 68, one of the ends of which carries the valve 44 and the opposite end of which is articulated on a rod 70 undergoing an axial longitudinal movement in the support 60 under the action of a motor 72, for example an electric, hydraulic or pneumatic motor. The support 60 comprises an arm 74 directly connected to a hydraulic cylinder or an endless screw, not shown, to pivot the support 60 around the axis X.

The total opening of the valve 44 consists first of all in disengaging it from its seat 54 by actuating the motor 72 which moves the rod 70 to the right in FIG. 2. This movement allows the valve to pivot, under the influence of the engine and its weight, around the pivot 66 in an anti-clockwise direction. The release of the valve 44 from the opening, i.e. the opening of the passage in the enclosure 28 consists in turning the assembly formed by the valve 44, the bent arm 68 and the support 60 around the axis X by acting on the arm 74 by the jack not shown, to place the valve 44 in a garage or opening position illustrated diagrammatically in FIG. 3 which shows a view turned through 90 _° with respect to that of FIG. 2. Closing the valve 44 comprises the same operations in reverse, c . the rotation of the support 60 around the axis X followed by a translation, towards the left in FIG. 2 of the rod 70 by the motor 72 to apply the valve 44 against its seat 54.

Given the position of the valve 44 when it is open (see FIG. 3 and FIG. 3a) the maximum filling level of the airlock 28 is represented by the line in broken lines 76 representing the discharge cone. This means that the space between the level 76 and the upper wall 58 of the airlock 28 is lost for the capacity of the latter.

This lost space is a function of the diameter of the opening and of the valve 44. In fact, when the valve 44 opens, it evolves in a circle whose radius corresponds to the distance between the point of intersection of the X axis of rotation of the valve with the vertical axis O of the airlock 28 and the level of the opening. However, if the diameter of the opening and of the valve 44 increases, the radius of the circle described by the valve also increases as shown in FIGS. 4,5 and 5a. By comparing these latter figures to FIGS. 2-3, it is recognized in particular that an increase in the section of the valve 44 from d to causes the diameter of the sphere of movement of the valve from D to D to pass, and significantly increases the space lost above the discharge cone 76. In other words, to reduce this lost space, it would be necessary to reduce the section of the valve 44, which is in contradiction with the tendency aiming to provide a filling opening as large as possible in the aim of reducing the filling time of the airlock 28.

To remedy this problem, the present invention provides another arrangement of the support 60 of the valve 44, which allows a less deep penetration of the valve 44 in the airlock 28 when it is opened. In other words, an arrangement of the support 60 according to the invention illustrated by FIG. 6, allows, for the same section of the opening of the airlock 28 a better filling thereof or, for the same filling of the airlock 28 an increase in the section of its opening.

This possibility is achieved by placing the support 60 as shown in FIG. 6, so that its axis of rotation X makes an acute angle with a horizontal plane, instead of being horizontal as in the execution of FIGS. 2 and 4.

The effect of this oblique arrangement of the axis of rotation of the valve 44 is twofold. By comparing FIG. 6 to FIG. 4, it can be seen that for a valve of the same section d, the diameter D of the sphere of movement of the valve 44 has significantly increased in FIG. 6. This is due to the fact that, by following the inclination of the X axis, the point of intersection of the latter with the O axis is lowered, which increases, of course, this distance to the valve 44, i.e. the radius of the valve displacement sphere.

By comparing between them Figures 5a and 7a which show, in horizontal projection the position of the valve 44 when open, we see that, in the embodiment of Figure 4, the center of the valve 44 is moved in a vertical plane diametral perpendicular to the plane of Figure 4, while in the embodiment of Figure 6, the displacement plane of the center of the valve is offset by an angle (see Figure 7a) relative to that of Figure 5a, l angle being proportional to the inclination of the X axis relative to the horizontal.

By comparing between them Figures 5 and 7 which are vertical sections each time containing the displacement curve of the center of the valve 44, i.e. according to the sectional planes aa in FIGS. 5a and 7a, it can be seen that the valve, in the open position, occupies in FIG. 5 an almost vertical and deeper position, while in the embodiment of FIG. 7 it is less inclined and therefore more raised. Since in the embodiment of Figure 7 the valve penetrates less deeply into the airlock 28 during opening, the maximum loading level may be higher. This difference is clearly visible in Figure 8 on which the loading level maximum for the embodiment of Figure 4 is represented by 76 and that of the embodiment of Figure 6 by 76 '.

The advantage achievable by the inclination of the axis of rotation of the valve 44 becomes all the more significant as this inclination becomes large. FIG. 9 shows an advantageous embodiment applying the principles of the present invention and in which the same reference numbers have been used as in the preceding figures to designate two corresponding elements. In this embodiment, the axis of rotation X of the valve 44 is strongly inclined relative to the horizontal, i.e. that the angle a 'is appreciably greater than the angle a in FIG. 6. This sharp inclination further descends the point of intersection between the axis X and the axis O, which greatly increases the radius of the sphere of displacement of the valve 44. This is the reason why the airlock 78 of the embodiment of FIG. 9 has the general shape of a pear, the widest section of which is at the level of the path printed on the valve. 44 by its inclined support 60.

The open position of the valve 44 is shown in broken lines on the axis of rotation X in FIG. 9. It will be noted that in this embodiment the valve 44 occupies a position even less inclined than that of FIG. 7, which further raises its lower edge and allows a filling which is even better than that of the embodiment of FIG. 6.

The end of the loading phase of the airlock 78 is schematically illustrated in Figures 10, 11 and 11a which correspond respectively to the views shown in Figures 6, 7 and 7a. Given the width of the airlock 78 in the upper region, it is necessary to provide a device for distributing the loading material in order to be able to direct it into the peripheral region of the airlock 78. For this purpose, the check valve 80 which regulates the flow of the loading material of the hopper 46 in the airlock 78 is designed in the form of a bell and is movable in the vertical direction, in a manner known per se by means not shown. To direct the loading material into the central region, the bell 80 is lowered into the position shown in broken lines. At the end of the loading phase, the bell 80 is gradually raised to move the fall path of the loading material away from the axis O and thus direct it towards the peripheral region of the airlock 78.

Claims (3)

1.

Images