GB2230847A

GB2230847A - Device for injecting preheated air into a shaft furnace

Info

Publication number: GB2230847A
Application number: GB8914974A
Authority: GB
Inventors: Gustave Hoelpes
Original assignee: Paul Wurth SA
Current assignee: Paul Wurth SA
Priority date: 1989-04-21
Filing date: 1989-06-29
Publication date: 1990-10-31
Anticipated expiration: 2009-06-29
Also published as: DE3920223A1; DE3920223C2; GB2230847B; FR2646230B1; GB8914974D0; JPH02285012A; FR2646230A1; LU87504A1; JP2791800B2

Description

P-PWU-190 - 1 DEVICE FOR INJECTING PREHEATED AIR INTO A SHAFT FURNACE is

The present invention relates to a device for injecting preheated air into a shaft furnace, composed of several separate elements consisting of an outer casing and an inner refractory lining and having at least one central tubular element connected, on one side. by means of a first joint and a first compensator to a first connector fixed to a circular pipeline supplying preheated air and surrounding the furnace and, on the opposite side, by means of a second joint and a second compensator to a second connector which which is extended by an elbow and a tuyere, the latter being articulated on the wall of the furnace by means of a third joint.

These devices, known more generally as "blast connections", involve problems of movability and sealing. In fact.. as a result of the temperature of the preheated air (a temperature of the order of 120CC or more) and the high temperature prevailing inside the furnace, the wall of the latter as well as the circular pipeline and the blast connection are exposed to thermal expansions and deformations which cause appreciable relative shifts between the circular pipeline and the wall of the furnace. The blast connection must therefore be capable of compensating the relative shifts, whilst at the same time preventing leaks of preheated gas or air.

To meet these requirements, U.S. Patent - No.

3,766,868 provides a blast connection of the type descri bed in the introduction. This blast connection has since been improved by the design of three universal ball-and socket joints of the type described in the document DE-C2-2218331. The three joints of this blast connection make it possible to compensate all the relative movements between the circular pipeline and the wall of the fur nace. Sealing in the region of the joints is obtained by means of concertina-type compensators, whilst mechanical stability is ensured by means of cardan connections associated with the two opposite ends of the central is tubular element in the region of the f irst and second ball-and-socket joints. These cardan connections preserve the freedom of movement of the joints, whilst at the same time guaranteeing that the width of the balland-socket joint is maintained.

Although these cardan connections perform the functions for which they were designed to the satisfaction of the users, they nevertheless unfortunately increase the cost price and weight of the blast connection.

The object of the present invention is to provide an injection device of the type described in the intro duction, which is of greater simplicity and which at the same time affords all the advantages of the known devices.

To achieve this object, the device provided by the present invention is characterized essentially by a pair of ties which are diametrically opposite one another on either side of the central element and the opposite ends of which are articulated respectively on the first and on the second connector, and by a frame arranged round the central element and articulated on this central element at two opposite cardinal points and on the two ties at the other two opposite cardinal points.

The joints at the four cardinal points are joints allowing pivoting about three axes parallel to one another and perpendicular to a plane defined by the longitudinal axes of the ties.

The two ties ensure a specific distance between the two connectors, whilst the central element is supported by the ties via the frame.

The joints between the ties and the two connectors and those of the frame about the central element make it possible for the latter to occupy all the orientations allowed by the ball-and-socket joint between this element and the opposite connectors.

The ball-and-socket joints can be designed in a conventional way, that is to say oriented parallel in the same direction or oriented in opposite directions, so 4 2 0' that their centres of curvature are located respectively at the centre of each of the adjacent connectors.

Other particular features and characteristics of the invention will emerge from the detailed description of some advantageous embodiments given below as an illustration, with reference to the accompanying drawings in which:

Figure 1 shows a diagrammatic view, in vertical section, of a conventional blast connection according to U.S. Patent 3,766,868; Figure 2 shows a similar view of a blast connection according to a f irst embodiment of the present invention; 1 Figure 3 shows a similar view of a blast connec tion according to a second embodiment of the present invention; Figures 4 and 5 show the central part of the blast connection in two directions perpendicular to one another; Figure 6 is a diagrammatic sectional view corresponding to that of Figure 4; Figure 7 is a view similar to that of Figure 6, showing an offset of the upper and lower connectors; Figure 8 shows a view similar to that of Figure 6 in respect of the inclination of the lower connector in relation to the upper connector, and Figures 9 to 11 show diagrammatic sectional views corresponding to that of Figure 5 and respectively illustrating the various sections in alignment and offset.

The known blast connection, designated by the reference 20 in Figure 1, connects a main circular pipeline 22 arranged round a blast furnace to the wall 24 of the latter. This blast connection 20 comprises a straight oblique section consisting of a tubular element 26 articulated at its upper end on a connector 28 fixed to the circular pipeline 22 and at its lower end on a connector 30 flanged to an elbow 32.

This elbow 32 is extended by a tuyere 34, the end of which is articulated on a nozzle 36 fastened in the wall 24 of the furnace. The upper joint 38 and the lower joint 40 of the element 26 are ball-and-socket joints, the jentres of curvature of which are identified by X and Y. Likewise, the joint between the tuyere 34 and the nozzle 36 is a ball-and-socket joint 42, the centre of curvature of which is designated by Z. The three points X, Y and Z consequently form a joint with three points in space, which allows sufficient angular shifts of the tuyere 34 and of the central element 26 to compensate all the relative movements between the circular pipeline 22 and the wall 24 of the furnace.

Sealing in the region of the joints 38 and 40 is achieved by means of concertina-type compensators 44, 46 fastened respectively to the tubular element 26 and to the adjacent connectors 28 and 30. Cardan joints 48, 50 connecting the central element 26 to the adjacent connectors 28 and 30 ensure mechanical stability and maintain a specific width of the ball-andsocket joint. All the elements of the blast connection consist of an outer metallic casing and of an inner refractory lining associated, if appropriate, with a sealing material in the region of the joints 38, 40 and 42.

The present invention proposes to eliminate the two cardan joints 48 and 50 of Figure 1 and replace them with a frame 52 (see Figures 2 and 3) which is articulated, on the one hand, on the central connector at two diametrically opposite points and, on the other hand, on a pair of ties themselves articulated on the connectors 28 and 30, as explained in more detail with reference to Figures 4 to 11. Figure 2 illustrates the use of this new design on a conventional blast connection, in which the ball-andsocket joints are oriented in the same direction. The various elements of this blast connection of Figure 2 corresponding to those of Figure 1 bear the similar references of the series 100.

Figure 3 shows the use of the design according to the present invention on a new blast connection, as provided in the Luxembourg Patent Application No. 87,283.

In the embodiment illustrated in Figure 3, the elements corresponding to those of Figure 1 bear similar references of the series 200. This embodiment differs -from that of Figure 2 in the reversal of the curvature of the lower joint 240, so that the two joints 238 and 240 have curvatures oriented in opposite directions, thus making it possible to reduce the length of the central element 226.

Figures 4 to 11 show the constructive and functional details of the stabilizing device provided by the present invention as a substitute for the cardan joints 48 and 50 of Figure 1. This device will be described by way of example with reference to the preferred embodiment of Figure 3. It is clear, however, that the device can be used in the embodiment of Figure 2 without any modification.

Figures 4 and 5 show side views of the central tubular element 226 equipped, on either side, with its compensators 244, 246 surrounding the ball-and-socket joints 238 and 240 not shown in these Figures.

A frame 52, for example square or preferably ring-shaped, is arranged round the central element 226, on which it is articulated by means of two diametrically opposite pivots 54 and 56, for example seated in passage orifices in the ring 52 and in the casing of the central element 226. The ring 52 can therefore execute a pivoting movement relative to the common axis 0 of the two pivots 54, 56, and vice versa. The ring 52 also possesses, offset at 90' relative to the pivots 54, 56, two diametrically opposite joints connecting it to two ties 58, 60. These joints can consist, in the simplest way, of two pairs of forks 62 and 64 which are welded externally to the ring 52 And in the rounded recess of which is engaged a crosspiece 66, 68 of round cross-section integral with the ties 58, 60. The axes of the crosspieces 66, 68 therefore form two pivoting axes between the ring 52 on the one hand and the ties 58, 60 on the other hand, and vice versa, these two axes both being parallel to the pivoting axis 0 described above.

Moreover, each of the two ties 58, 60 is articulated respectively on the upper connector 228 and lower connector 230 at its upper and lower ends. Each of these jont; can consist of a simple hinge 70 comprising a pivoting hub 72 engaged through a double lug fixed to the connector in question and an orif ice at the end of the tie 58 or 60. The passage orifices at the ends of the ties 58, 60 are made as oblong holes and preferably have rounded bearing surf aces, in order also to allow the ties 58, 60 to pivot in the plane of Figure 5.

The hinges 72 can also be replaced by more sophisticated joints, for example knuckles. It should be noted that, to allow the correct functioning of the device, the axes of the hubs must necessarily pass through the centres of curvature X and Y of the ball-andsocket joints 238, 240.

The ties 58 and 60 consequently maintain a constant and predetermined distance between the connectors 228 and 230, whilst by means of the ring 52 they carry the central element 226 in a floating manner between the connectors 228 and 230.

Figures 6 to 11 illustrate different possibilities for relative movements and pivoting between the connectors 228 and 230 and how these movements are compensated by corresponding positioning of the central element 226.

The relative movements and pivoting between the connectors 228 and 230 which are illustrated in Figures 6 to 8 subject to stress only those joints in the region of the hinges 72 between the ties 58, 60 and the connectors, whereas the joints in the region of the ring 52 are not subjected to stress, because, as shown in Figures 7 and 8, the latter maintains its neutral diametral position of Figure 6 in relation to the ties and to the central element 26.

In contrast, the transverse deformations relative to the plane of Figures 6 to 8 and illustrated in Figures 9 to 11 subject the joints in the region of the ring 52 to stress. As shown more particularly in Figures 10 and 1 is 11, the movements in this plane cause a parallel deformation between the ties 58, 60 and the ring 52 as a result of the pivoting of the latter about the axis 0 in relation to the central element 226 and a result of relative pivoting between the ring 52 and the ties 58, 60.

It should be noted that, as an illustration, Figures 6 to 11 show elementary movements (exaggerated in the Figures to make it easy to understand them), but in practice the movements of the blast connection are more complex, that is to say the offsets and inclinations shown in these Figures can occur at the same time.

The combination of the ring 52 with the ties 58 and 60 therefore makes it possible to perform the same functions as the two cardan joints 48 and 50 of Figure 1, whilst at the same time being of simpler and cheaper construction. In other words two cardan joints have been replaced by only one which, moreover, can be lighter because the frame only has to carry the central element. whereas the conventional cardan joints must support a pressure prevailing inside the blast connection and are therefore exposed to stresses approximately ten times higher.

The invention has been described by way of example with reference to a blast connection with balland-socket joints. It must be pointed out, however, that the invention is not limited to this type of blast connection, but can also be used on a blast connection with trapezoidal or cascade-type joints.

Furthermore, the combination of the ring 52 with the ties 58, 60 affords an additional advantage. In fact, the permanent and forced parallel alignment of the axis of the central element 226 with the ties 58, 60 allows these to assist the ideal positioning of this central element 226 in such a way that, in all the positions and orientations, its longitudinal axis passes through the centres of curvature X and Y of the ball-andsocket joints 228 and 230, thus eliminating any possibility of random movements and superfluous friction in the region of the joints.

- 8

Claims

Claims.

1. Device for injecting preheated air into a shaft furnace, composed of several separate elements consisting of an outer casing and an inner refractory lining and having at least one central tubular element connected, on one side, by means of a first joint and a first compensator to a first connector fixed to a circular pipeline supplying preheated air and surrounding the furnace and, on the opposite side by means of a second joint and a second compensator to a second connector which is extended by an elbow and a tuyere, the latter being articulated on the wall of the furnace by means of a third joint wherein a pair of ties are arranged diametrically opposite on either side of the central element and the opposite ends of which are articulated respectively on the first and on the second connector and by a frame arranged round the central element and articulated on this central element at two opposite cardinal points and on the two ties at the other two opposite cardinal points.

2. Device according to Claim 1, characterised in that the frame is ringshaped.

3. Device according to Claim 1, characterised in that the joints at the four cardinal points of the frame are joints allowing pivoting about three axes parallel to one another and perpendicular to a plane defined by the longitudinal axes of the ties.

1 ll

4. Device for injecting preheated air into a shaft furnace substantially as described herein with reference to the figures.

Published 1990 at The Patent Office. State House. 6671 High 1101borri. London WC1R 4TP Further copies maybe obtained from The Patent Office. Sales Branch. St Mary Cray, Orpington. Kent BR5 3RD. Printed by Multiplex techniques ltd, St Mary Cray, Kent. Con. 1187