EP0363576A1 - Apparatus for blowing preheated air into a shaft furnace - Google Patents

Abstract

The device comprises a central tubular element (126) which is connected to adjacent pipes (128) (130) by spherical joint orientations (138) (140) and compensators (144) (146) and a pair of tie rods connecting said tubes adjacent to each other. In order to reduce the length of the assembly, the ball joints (138) (140) are oriented in opposite directions so that their respective centers of curvature are on the axis of each of the adjacent pipes (128) (130 ).

Description

The present invention relates to a device for injecting preheated air into a shaft furnace, consisting of several separate elements consisting of an outer shield and an inner refractory lining and comprising at least one central tubular element connected, on one side, by a first ball joint and a first compensator to a first tube integral with a circular duct for supplying preheated air surrounding the furnace and, on the opposite side, by a second ball joint and a second compensator to a second tube which is extended by an elbow and a nozzle, the latter being articulated by a third articulation with a spherical joint with respect to the wall of the furnace and further comprising at least one pair of tie rods connecting, by articulated means, the first tube to the second tube and in which said first articulation is oriented so that its center of curvature is on the axis of said first tube inside thereof.

These devices, more generally known under the name of "wind carrier" are exposed to mobility and sealing problems. Indeed, as a result of the high temperature of the preheated air (temperature of 1,200 ° C or more) and the high temperature inside the oven, the wall of the oven, as well as the circular pipe and the blower are exposed to thermal expansions and deformations causing significant relative movements between the circular pipe and the oven wall. It is therefore necessary that the wind carrier is able to compensate for these relative displacements while avoiding leaks of gas or preheated air.

To meet these requirements, US Patent No. 3,766,868 provides a wind carrier of the kind described in the preamble. This wind carrier was subsequently perfected by the design of universal joints with spherical joints of the kind described in document DE-C2-2218331. The three articulations of this wind carrier allow the compensation of all relative movements between the circular duct and the wall of the oven. The tightness at the joints is ensured by bellows compensators, while the mechanical stability is ensured by cardanic connections associated at the level of the first and of the second articulation with a spherical joint at the two opposite ends of the tubular element. central.

To reduce the amplitude of the angular displacements of the central element and thus relieve the compensators, it is desirable that the distance between the centers of articulation of this element is as great as possible. On the other hand, to reduce the size and cost of the wind carrier, it is desirable to reduce the dimensions.

The object of the present invention is to provide an injection device of the kind described in the preamble which allows a better compromise between these contrary requirements.

To achieve this objective, the device proposed by the present invention is essentially characterized in that the second articulation is oriented in the opposite direction relative to the first articulation and in that its center of curvature is on the axis of the second tubing, inside of it or of the elbow.

By orienting the two articulations of the central element in opposite directions, it is possible to substantially reduce the length of this central element while maintaining the same distance between the centers of its two articulations.

According to a first embodiment, the tie rods are connected to the two tubes by joints, the centers of which are respectively in two diametrical planes of the tubes, each containing the center of curvature of one of said first or second spherical articulation.

According to another embodiment, the end of each of the tie rods is connected to a flange of said said first or second tubing by a pair of washers with adjacent spherical sliding surfaces, the center of curvature of which is situated beyond the end of the tie rod in a diametral plane of the tubing containing the center of curvature of said first or second articulation spherical.

According to an advantageous embodiment, the central tubular element is connected to the tie rods by a device for guiding and supporting the central element.

• La figure 1 représente une vue schématique, en coupe verticale, d'un porte-vent classique selon le brevet US 3766868 ;
• La figure 2 représente une vue analogue d'un porte-­vent conformément à la présente invention ;
• Les figures 3 et 4 représentent deux coupes verti­cales perpendiculaires l'une à l'autre d'un premier mode de réalisation de la partie centrale du porte-vent selon la présente invention.
• Les figures 5 à 8 représentent des vues analogues à celles des figures 3 et 4 et illustrant les différents déplacements de l'élément tubulaire central par rapport aux tubulures adjacentes ;
• La figure 9 illustre un second mode de réalisation de l'élément central ;
• La figure 9a, montre en détail, une partie agrandie de la figure 9 ;
• Les figures 10 et 11 montrent la partie centrale du porte-vent suivant deux directions perpendiculaires l'une à l'autre, d'un troisième mode de réalisation;
• La figure 12 est une vue schématique en coupe correspondant à celle de la figure 10;
• La figure 13 est une vue analogue à celle de la figure 10 montrant un désaxement des tubulures supé­rieures et inférieures;
• La figure 14 représente une vue analogue à celle de la figure 10 en cas d'inclinaison de la tubulure inférieure par rapport à la tubulure supérieure et
• Les figures 15 à 17 montrent des vues schématiques en coupe correspondant à la figure 11 et représentant respectivement les différentes sections en alignement et en désaxement.

Other particularities and characteristics of the invention will emerge from the detailed description of some advantageous embodiments, presented below, by way of illustration, with reference to the appended drawings in which:

• Figure 1 shows a schematic view, in vertical section, of a conventional wind carrier according to US Pat. No. 3,766,868;
• Figure 2 shows a similar view of a wind carrier according to the present invention;
• Figures 3 and 4 show two vertical sections perpendicular to each other of a first embodiment of the central part of the wind carrier according to the present invention.
• Figures 5 to 8 show views similar to those of Figures 3 and 4 and illustrating the different displacements of the central tubular element relative to the adjacent tubes;
• FIG. 9 illustrates a second embodiment of the central element;
• Figure 9a, shows in detail, an enlarged part of Figure 9;
• Figures 10 and 11 show the central part of the wind carrier in two directions perpendicular to each other, of a third embodiment;
• Figure 12 is a schematic sectional view corresponding to that of Figure 10;
• Figure 13 is a view similar to that of Figure 10 showing a misalignment of the upper and lower tubes;
• FIG. 14 represents a view similar to that of FIG. 10 in the event of inclination of the lower tubing relative to the upper tubing and
• Figures 15 to 17 show schematic sectional views corresponding to Figure 11 and respectively representing the different sections in alignment and offset.

The known wind carrier shown in Figure 1 by the reference 20 connects a main circular pipe 22, arranged around a blast furnace, to the wall 24 thereof. This blower 20 has a rectilinear oblique section consisting of a central tubular element 26 articulated by its upper end on a tube 28 secured to the circular pipe 22 and by its lower end on a tube 30 which is clamped on an elbow 32. This elbow 32 is extended by a nozzle 34 whose end is articulated on a nozzle 36 fixed in the wall 24 from the oven. The upper articulation 38 and the lower articulation 40 of the element 26 are spherical joint joints whose centers of curvature are identified by X and Y. Likewise the articulation between the nozzle 34 and the nozzle 36 is a joint 42 with a spherical joint whose center of curvature is represented by Z. The three points X, Y and Z therefore constitute a three-point articulation in space which allows sufficient angular displacements of the nozzle 34 and of the central element 26 to compensate for all the relative movements between the circular pipe 22 and the wall 24 of the oven.

Sealing at the joints 38 and 40 is ensured by bellows compensators 44, 46 fixed respectively on the tubular element 26 and the adjacent pipes 28 and 30. Mechanical stability is ensured by cardan joints 48, 50 connecting also the central element 26 to the adjacent pipes 28 and 30. All the elements of the blower are made up of an external metal shield and an associated internal refractory lining Lement to a sealing material at the joints 38, 40 and 42.

The distance between the centers of curvature X and Y of the joints 38 and 40 is represented by 1 in FIG. 1. The amplitudes of the angular displacements of the central element 26 and, consequently, the stresses of the compensators 44 and 46 will be as much smaller as this distance 1 is greater. On the other hand, lengthening the length 1 increases the dimensions of the wind carrier.

In accordance with the present invention, the lower articulation of the central tubular element is turned over so that the two upper and lower ends of this central element become concave, while the corresponding adjacent ends of the pipes of the circular pipe and that of the elbow become convex. This windshield proposed by the present invention is shown in Figure 2 and the elements corresponding to those of Figure 1 bear the similar references of the 100 series. As can be seen from this Figure 2, the centers of curvature X and Y of the ball joints 138 and 140 are separated by a distance l ′ which, in the example shown, is equal to the distance l in FIG. 1. On the other hand, the total length of the central element 126 has been considerably reduced, the difference in length being illustrated by the distance between the axis O ′ of the circular pipe of FIG. 2 and the location of the axis O of the wind carrier of FIG. 1, which has also been shown in FIG. 2. This shortening of the wind carrier 120 allows consequently, a lowering of the circular pipe 122 and a bringing it closer to the wall of the furnace. The result, of course, is a reduction in size and a reduction in the cost of manufacturing the wind carrier.

It would also be possible to keep the length of the central element 26 of FIG. 1, which would allow an extension of the distance l between the centers X and Y of the spherical joints 38 and 40, that is to say a reduction the amplitude of the angular displacements of this element.

Figures 3 and 4 show in more detail the two joints 138 and 140 on either side of the central tubular element 126. The radii of curvature R1 and R2 of the two spherical joints 138 and 140 are preferably equal.

The present invention also proposes the elimination of the cardan joints 48 and 50 of FIG. 1. However, since the compensators 144, 146 are not able to support the weight of the wind carrier, a pair of tie rods has been provided diametrically opposite to each other and connecting the upper tube 128 to the lower tube 130. In the embodiment of Figures 3 and 4, these tie rods 152, 154 are simply engaged on pivots 156 integral with the pipes 128 and 130. However, to allow the necessary mobility described with reference to the following figures, the tie rods 152, 154 must be engaged on the pivots 156 with sufficient clearance. To allow this mobility it is also necessary that the axis of the two pivots 156 of the tubing 128 passes through the center of curvature X of the upper articulation 138. Similarly, the lower pivots 156 must be fixed on the tubing 130 so that their axes also pass through the center of curvature Y of the lower joint 140.

Figures 5 to 8 illustrate different possibilities of mobility of the blower. FIG. 5 illustrates, for example, a relative lateral offset, of an amplitude s between the upper tube 128 and the lower tube 130. Such an offset can, for example, be caused by a horizontal displacement of the circular pipe 122 relative to in the oven or a rotation of this pipe with respect to the oven. As shown in FIG. 5, the axes of the pipes 128 and 130 remain parallel to each other while the central element 126 compensates for this offset by positioning itself so that its axis passes through the centers of curvatures X and Y of the two joints 138 and 140. This movement causes, on the one hand, a compression of the undulations of the compen sators 144 and 146 and a relaxation of the undulations of these compensators on the opposite side.

FIGS. 6 and 7 show flexions, respectively in one direction and in the opposite direction of the wind carrier at the level of the central element 126. In each case the axis of the lower tube 130 is inclined at an angle by relative to the axis of the upper tube 128. This bending is compensated by the central element 126 which is automatically positioned so that its axis passes through the centers of curvature X and Y of the two joints, that is to say that its axis forms an angle α / 2 with the axis of the upper tube 128 and an angle α / 2 with the axis of the lower tube 130. The positions of FIGS. 6 and 7 result essentially from a relative vertical movement between the circular pipe 122 and the wall 124 of the oven.

Figure 8 shows a lateral offset between the upper and lower pipes 128 and 130 similar to that of Figure 5, but in a direction perpendicular to the movements of Figure 5, that is to say the offset of Figure 8 is located in the plane of Figure 2. It should be noted that Figures 5 to 8 show, by way of illustration, elementary movements, but in practice, the movements of the blower are more complex, it is that is, the offsets and inclinations shown in Figures 5 to 8 can occur at the same time.

Figure 9 shows an advantageous embodiment which allows a shortening of the tie rods of the embodiment of Figure 3. In this embodiment of Figure 9, the two pipes 228 and 230 respectively have a circular flange 258 and 260 which are attached to the compensators 244, 246 and which are crossed by tie rods 252, 254.

The connection between the ends of the tie rods 252, 254 and the flanges 258 and 260 is illustrated in detail in FIG. 9a and with reference to the connection between the tie rod 254 and the flange 258, the three other connections being identical to that of the figure. 9a. The flange 258 has a passage opening 262 of the tie rod 258 which is wide enough to allow a certain inclination of the tie rod 254 relative to the flange 258 as a result of the movements illustrated in FIGS. 5 to 8. The tie rods are maintained by nuts 264 screwed onto the ends of the tie rods, outside the flanges 258, 260. Between each nut 264 and the corresponding flange 258 or 260 are two washers 266, 268 whose adjacent surfaces slide one over the other by following the inclination of the tie rod relative to the flange. According to the particularity of this embodiment, the adjacent sliding surfaces of the washers 266, 268 have spherical curvatures whose center of curvature is located beyond the flanges 258, 260 on the axis of the tie rods 252, 254 or on the extension of these axes. The center of curvature of the washers 266, 268 must also be located in a diametral plane of the tube 228 containing the center of curvature X of the spherical joint 238 between this tube 228 and the central element 226. note that the two washers 266 and 268 can be replaced respectively by a seat secured to the flange 258 and a curved surface of the nut 264.

The advantage of the design according to FIGS. 9 and 9a is that one can either bring each of the flanges 258, 260 closer to the central element 226 by a distance R corresponding to the radius of curvature of the washers 266, 268 and reduce by 2R the length of each tie rod 252, 254, or increase the radii of curvature of the two spherical joints 238, 240 and thus lengthen the distance between their center of curvature X and Y.

Figures 5 to 8 have shown that the compensation of the different relative movements between the upper and lower tubing is achieved by aligning the axis of the central element on the centers of curvature X and Y of the two spherical joints. It is proposed, in the embodiment of FIGS. 10 to 17, to assist the optimal positioning of the central element 226 to avoid any random movements and superfluous friction at the joints of the joints.

Figures 10 and 11 show side views of the central tubular element 326 provided on either side with its compensators 344, 346 surrounding the spherical seals 338 and 340, not visible in these figures.

A frame 352, eg square or, preferably, in the form of a ring, is arranged around the central element 326 to which it is articulated by two pivots 354 and 356, diametrically opposite, eg housed in openings passage of the ring 352 and the shielding of the central element 326. The ring 352 can therefore perform a pivoting movement relative to the common axis O of the two pivots 354, 356 and vice versa. The ring 352 further comprises, offset by 90 ° relative to the pivots 354, 356, two diametrically opposite articulations, connecting it to two tie rods 358, 360. These articulations can be formed, in the simplest way, by two pairs of forks 362 and 364 welded externally to the ring 352 and in the rounded hollow of which is engaged a cross-piece 366, 368 with round section, integral with the tie rods 358, 360. The axes of the cross-pieces 366, 368 therefore form two pivot axes between the ring 352, on the one hand, and the tie rods 358, 360, on the other hand, and vice versa, these two axes being both parallel to the pivot axis O described above.

Each of the two tie rods, 358, 360 is, moreover, articulated by its upper and lower ends respectively to the upper tubes 328 and lower 330. Each of these articulations can be constituted by a simple hinge 370 comprising a pivoting hub 372 engaged through a double eyelet secured to the tubing concerned and an opening at the end of the tie-rod 358 or 360. The passage openings at the ends of the tie-rods 358, 360 are made in oblong holes and preferably have rounded bearing surfaces in order to allow also pivoting of the tie rods 358, 360 in the plane of FIG. 11.

The hinges 372 can also be replaced by more sophisticated articulations, eg ball joints to make an arrangement in accordance with FIG. 9.

The tie rods 358 and 360 therefore maintain a constant and predetermined distance between the pipes 328 and 330, while they carry, by means of the ring 352, the central element 326 floating between the pipes 328 and 330.

FIGS. 12 to 17 illustrate different possibilities of relative movements and pivotings between the pipes 328 and 330 and the manner in which these movements are compensated by a corresponding positioning of the central element 326.

The relative movements and pivotings between the tubes 328 and 330 which are illustrated in FIGS. 12 to 14 stress only the articulations at the hinges 372 between the tie rods 358, 360 and the tubes, while the articulations at the level of the ring 352 are not used because, as shown in FIGS. 12 and 13, the latter retains, relative to the tie rods and the central element 326, its neutral diametrical position in FIG. 10.

On the other hand, the transverse deformations relative to the plane of FIGS. 12 to 14 and illustrated by FIGS. 15 to 17 stress the articulations at the level of the ring 352. As shown more particularly in FIGS. 16 and 17, the displacements in this plane cause parallel deformation between the tie rods 358, 360 and the ring 352 by pivoting of the latter around the axis O relative to the central element 326 and by relative pivoting between the ring 352 and the tie rods 358, 360.

Claims (7)

1. Device for injecting preheated air into a shaft furnace consisting of several separate elements consisting of an outer shield and an inner refractory lining and comprising at least one central tubular element (126) connected, on one side, by a first articulation (138) with a ball joint and a first compensator (144) to a first tube (128) integral with a circular duct (122) for supplying preheated air surrounding the oven and, on the opposite side, by a second articulation (140) with a ball joint and a second compensator (146) to a second tube (130) which is extended by an elbow (132) and a nozzle (134), the latter being articulated by a third joint (142) with ball joint relative to the wall (124) of the oven and further comprising at least one pair of tie rods (152, 154) connecting, by articulated means, the first pipe (128) to the second pipe (130) and in which said first articulation (138) is oriented so that its center of curvature (X) is on the axis of said first tube (128), inside the latter, characterized in that said second articulation (140) is oriented in the opposite direction with respect to said first articulation (138) and in that its center of curvature (Y) is on the axis of said second tube (130) inside the latter or the elbow (132). 2. Device according to claim 1, characterized in that the tie rods (152, 154) are connected to the two pipes (128, 130) by joints, the centers of which are respectively in two diametrical planes of the pipes (128, 130) each containing the center of curvature (X), (Y) of one of said first or second spherical joints (138, 140). 3. Device according to claim 1, characterized in that the end of each of the tie rods (252, 254) is connected to a flange (258, 260) of said first or second pipes (228, 230) by a pair of washers ( 266, 268) with adjacent spherical sliding surfaces, the center of curvature of which is situated beyond the end of the tie rod (252, 254) in a diametrical plane of the tube (228, 230), containing the center of curvature (X), (Y) of said first or second ball joint (238, 240). 4. Device according to any one of claims 1 to 3, characterized in that the central tubular element (326) is connected to the tie rods (358, 360) by a device for guiding and supporting the central element (326 ). 5. Device according to claim 4, characterized in that the guide and support device consists of a frame (352) disposed around the central element and articulated by two cardinal points opposite to this central element (326) and by the other two cardinal points opposite to the two tie rods (358), (360). 6. Device according to claim 5, characterized in that the frame (352) is in the form of a ring. 7. Device according to claim 5, characterized in that the joints at the four cardinal points of the frame (352) are joints allowing pivoting around three axes parallel to each other and perpendicular to a plane defined by the longitudinal axes of the tie rods.

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