GB2207741A

GB2207741A - Machine for piercing a shaft furnace taphole

Info

Publication number: GB2207741A
Application number: GB08818343A
Authority: GB
Inventors: Patrick Millen; Jean Metz; Pierre Mailliet
Original assignee: Paul Wurth SA
Current assignee: Paul Wurth SA
Priority date: 1987-08-04
Filing date: 1988-08-02
Publication date: 1989-02-08
Anticipated expiration: 2008-08-02
Also published as: GB2207741B; DE3825100C2; IT8821609A0; DE3825100A1; GB8818343D0; FR2619036B1; FR2619036A1; LU86963A1; IT1226568B

Description

- 3 The hydraulic jack is di sposed between the two boxes in such a manner

that the end of its rod bears against the stand and that its cylinder is connected to each of the two boxes.

The aforesaid means immobilizing the two boxes preferably consist of two pairs of stops fixed respectivety at predetermined points on each side of the top strands of the closed chains.

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

Figure 1 is a side view of the piercing machine in the position in which it grips a piercing rod; Figure 1A shows the machine of Figure 1 partly in plan view and partly in horizontal section; Figure 2 is a section taken on the line II-II in F i gure 1; Figure 3 F igure 6; Figures 4 and 5 are respectively sections taken on the lines IV-IV and V- V in Figure 1; Figures 6 and 6A are views similar to those in Figures 1 and 1A showing the machine in the piercing rod extraction phase, and Figures 7 and 7A are views similar to those in Figures 1 and 1A after the extraction of the piercing rod.

A description will first be given of the machine in the static state, referring simultaneously to Figures 1 to 5.

For reasons of visibility the machine shown in Figure 1 has been opened Longitudinally along the verticat plane identified by the line A in Figure 1A. This Figure 1A shows a plan view of the machine where the part above the longitudinal axis 0 is concerned, and a horizontat section through said axis where the part below the axis 0 is concerned.

is a section takn on the line III-III in The machine comprises a longitudinal stand 10 mounted in known manner at the end of a carrier arm adapted to pivot about a bracket (not shown) erected close to the furnace. The stand consists essentially of two symmetrical longitudinal plates 12 and 14, the plate 14 not being visible in Figure 1A, although it is visible in Figures 2 to 5. These two plates 12 and 14 are joined at the front of the machine and carry means for attachment to a support 13 fastened to the wall of a shaft furnace 16.

The reference 18 designates a piercing rod, which in the example illustrated is a lost rod, that is to say one which enables the taphole to be opened by its extraction from the furnace wall. This extraction is effected with the aid of a coupling device 20 enabling the free en d of the rod 18 to be gripped and, through the displacement of a carriage 22 along the stand 10, enabling the rod 18 to be freed from the furnace wall. The carriage 22 or the coupling device 20 may if necessary be. associated with a unidirectional percussion tool in order to facilitate the disengagement of the rod 18.

This first carriage 22 is slidably suspended by running rollers 24 (see Figure 4) below a second carriage 26, which is turn is adapted to-slide longitudinally in relation to the stand 10. For this purpose the carriage 26 is composed essentially of two lateral longitudinal beams 28, 30 suspended respectively by running rollers 32, 34 on the two fixed plates 12 and 14 of tYe stand 10 (see Figures 2 to 5).

An open chain 36, which may a Galle type chain (the bicycle chain kind), is stretched inside the carriage 26 around two return pulleys 38, 40 mounted at opposite ends of the carriage 26, between the beams 28 and 30, on pivots fixed in support blocks 42, 44. One end of the chain 36 is fixed at 46 to the stand 10, approximately in the central region of the latter. The other end of the chain 36 is likewise fastened to the stand 10 in the region of the rear pulley 40 by means of a tensioner 48.

V 1 4 jack enables the rod to be completely extracted without the assistance of an auxiliary translatory motor.

In order to achieve this aim the invention proposes a piercing machine of the kind described in the preamble, which in one preferred embodiment is essentially characterized in that the second carriage is provided with an open chain passing around two return pulleys provided at the opposite ends of said carriage and having its two ends fastened to said stand, in that said first carriage is fixed to said open chain, and in that the extensible part of the jack is connected to the second carriage by two connections, of which one, which acts indirectly with the aid of a stepup device, automatically taking the place of the other, whose action is direct, starting from a predetermined position of the second carriage.

Two boxes are mounted slidably inside the second carriage and each contains a closed chain, these two closed chains being connected along a straight portion to said second carriage. In addition, each of these boxes is connected to the extensible part of the jack, while the two closed chains are provided with means for immobilization against a cross member fastened to the stand.

The first carriage is carried by the second carriage by means of running rollers. This second carriage is essentially composed of two parallel beams likewise supported by means of running rollers along the two lateral sides of the stand and connected at each of their ends by cross members carrying the return pulleys for the open chain.

The two boxes are disposed one on each side of the open chain and are carried by running rollers on the inside flanks of each of the beams of the second car- riage.

The closed chains each extend around two return pulleys carried by each box, one of each pair of pulleys being mounted in a movable stirrup associated with chain tensioning means.

2 12' 0 7 7 4 MACHINE FOR PIERCING A SHAFT FURNACE TAPHOLE.

The present invention relates to a machine for piercing a shaft furnace taphole, comprising a stand mounted at the free end of a carrier arm and provided with moans of support on the furnace wall, and a device intended for gripping a rod and mounted on a first carriage movable along a second carriage, the latter in turn being movable relative to the stand through the action of a hydraulic jack.

The invention relates more particulary but is not not limited to a piercing machine for carrying out a process by which the closing and opening of the taphole comprise respectively an operation for placing a piercing rod in position and an operation for extracting the piercing rod, which is left in the mass of the taphole between two successive tappings, in contrast to conventional drilling machines designed to open the taphole by drilling with the aid of a percussion drill.

Both conventional drills and lost-rod machines required up to the present time a powerful bidirectional pneumatic percussion tool. It is however well known that a pneumatic toot is extremely noisy and that a percussion tool gives rise to substantial mechanical stresses which cause wear or fracture of the most vulnerable components.

As a'remedy, the document EP-A-0,128,432 proposed a machine of the kind described in the preamble, in which the bidirectional-percussion tool is replaced by a less powerful unidirectional percussion tool, the lost power being made up by a hydraulic jack serving to release the rod by a transtatory movement of the stand. Unfortunate- ly, because of the Length of the piercing rod, the jack does not enable the Latter to be completely extracted, so that use must still be made of an auxiliary motor to move the carriage carrying the percussion tool and the rod along the stand.

The present invention seeks to provide a new machine of the kind described above, in -which the hydraulic The chain is therefore the end 46 and the tensioner 48.

Inside the carriage 26 is disposed a hydraulic jack 50, which is mounted on the axis 0 and which, in its retracted position shown in Figure 1, extends substantially over the Length of the open portion of the chain 36. This jack 50 is pivoted by the end of its rod 52 on a support-54 welded to a cross member 56, which in turn is welded between the two side plates 12 and 14 of the stand 10. On the opposite side to the rod 52 the cylinder 58 of the jack 50 bears against the block 44, which is fastened to the carriage 26 and which carries the rear return pulley 40 for the open chain 36. It is obviously also possible to reverse the jack 50 so that its rod acts on the block 44 if the constructional arrangement allows this.

Inside the carriage 26 are likewise disposed two boxes 60, 62 extending symmetrically on each side of the jack 50. These boxes 60, 62 are supported respectively by running rollers 63 on the inside flanks of the beams 28 and 30 of the carriage 26. In other words, the boxes 60, 62 are slidable relative to the carriage 26, and vice v e r s a.

Each of the boxes 60, 62 has a connection to the cylinder 58 of the jack 50 ' such as that represented by the boss 64, which is engaged in a corresponding notch in the box 60. Inside each of the boxes 60, 62 is disposed a closed chain 66, 68 stretched around two return pulleys, as illustrated at 70 and 72 in Figure 1A. In each of the boxes one of the pulleys 72 is mounted in a sliding stirrup 74, the posi- tion of which is adjustable with the aid of a device 76 regulating the tension of the chain 66, the device regulating the tension of the chain 68 not being visible in the drawings. The two chains 66, 68, which like the open chain 36 are preferably of the Galle chain type, each have a rigid connection 78, 80 to the side beams 30 and 28 respectively on the carriage 26. These connections 78, 80. shown in Figures 3 and 4, are each situated on the lower strand of the two chains 66, 68 close to the return pulley situated on the furnace side in the position shown in Figure 1. On the upper strand of each of the chains 66, 68 two pairs of stops 82, 84 and 86, 88 are disposed diametrically opposite these fastenings 78 and 80. As will be seen further on, these stops are intended for cooperation with two cross members 90, 92 welded between the side plates 12 and 14 of the stand 10. These stops 82, 84 and 86, 88,. although having clearly determined fixed positions on the chains 66, 68, can never theless be changed in position if it is desired to modify the working conditions of the machine.

A description will now be given of the operation of the machine with reference to Figures 1, 6 and 7. If, starting from the position shown in Figure 1, the hydraulic jack 50 is operated, it will by means of its cylinder 58 push the block 44 back towards the right, and at the same time, because of its connection to the boxes 60 and 62, will drive them in the same direction. In other words, the assembly consisting of the two carriages 22 and 26 and the boxes 60 and 62 follows the movement of the jack as a unit in-order to start the extraction of the rod 18 from the wall of the furnace 16. This movement can continue until the stops 82, 84, 86 and 88 come into contact with the cross member 92, which thus stops the translatory movement of the boxes 60 and 62 in the position shown in Figure 6.

If it is assumed that the elongation of the jack 50 is equal to a Length X to bring the stops 82, 84, 86, 88 into contact with the cross member 92, the carriage 26 will consequently undergo a backward movement corresponding to the length X in relation to the furnace wall. However, since the open chain 36 is fixed by its two ends on the stand 10, which remains stationary, the chain 36 unwinds around its pulleys 38, 40, relative to the carriage 26, to the extent of a length X. In other words, each point on the lower strand of the chain 26 moves away from the furnace wall by an absolute magnitude corresponding to 2X. In view of the fact that the carriage 22 is connected at 96 to the chain 26, the latter is displaced, between the positions shown in Figures 1 and 6, by a length 2X relative to the furnace.

This fir-st phase, which comprises passing from the position shown in Figure 6 to that shown in Figure 7, is the'phase of release or pulling of the rod 18 from its position in the taphole. If the thrust of the hydraulic jack 50 is equal to p, the pressure force against the support 13 is equal to p/2 and the tensile force on the bar 18 is also equal to p/2. On the other hand, if the speed of extension of the jack 50 is equal to v, the speed of the carriage 22 and of the rod 18 will be equal to 2v. it is therefore possible to choose a reasonable compromise between the dimensions of the jack and its operating speed, so as to pull out the bar with a great force and a low speed of the jack.

If the jack 50 continues its action from the position shown in Figure 6, the boxes 60 and 62 are still subjected to the traction of the jack towards the right in Figure 6. However, in view of the fact that the stops 82, 84, 86 and 88 are locked by the cross member 92, the boxes 60 and 62 are displaced towards the right, while the closed chains 66 and 68 unwind in the counterclockwise direction about their pulleys in each of the boxes 60 and 62. In view of the fact that the chains 66, 68 are connected by their lower strands and by their fastenings 78 and 80 to the carriage 26, the latter is thus moved to the right in the drawings because of the movement of the closed chains 66 and 68. Since the movement of the chains 66 and 68 is composed of a translatory movement corresponding to the movement of the jack 50 and of a simultaneous rotary movement, the fastenings 78 and 80 are thus moved at twice the speed of the boxes 60 and 62, so that the carriage 26 moves telescopically out of the boxes 60, 62 (see Figure 7) by relative sliding with the aid of the 1 - 8 -, running rollers 63 between the carriage 26 and the boxes 60 and 62. Assuming that the length of displacement of the jack 50 between the positions shown in Figures 6 and 7 corresponds to the length y, the carriage 26 is consequently moved away from the furnace wall by a length equal to 2y (see Figure 7). As in the preceding phase, a displacement of the carriage 26 gives rise to a simultaneous unwi nding of the open chain 36, which is superimposed on the translatory movement of the carriage 26. Consequently, if the carriage 26 is moved in this second phase by a length equal to 2y, the first carriage 22 will undergo a relative displacement of 2y in relation to the second carriage 26, so that the absolute displacement of the first carriage 22 corresponds to a length equal to 4y.

Still assuming that the speed of extension of the jack 50 in its second phase is equal to v, the carriage 22 is displaced at a speed equal to 4v. On the other hand the tensile force on the bar 18 is only one quarter of the thrust force of the jack 50.

It is therefore found that a strong force is available for releasing the bar in the first phase at a relatively low speed, while in the second phase, which may be considered as the actual extraction, the translatory speed is higher whereas the tensile force is lower.

The above data, translated into figures, mean that if the jack undergoes an extension of 40 cm in the first phase and an extension of 85 cm in the second phase, that is to say a total of 125 cm, the rod 18 is displaced a distance of 80 cm in the first phase and a distance of 340 cm in the second phase, that is to say a total travel of 4.20 m for a stroke of only 1.25 m of the hydraulic jack.

The operation of the machine is similar for the placing in position of the rod 18. In a first phase the travel and the speed of the first carriage are twice the speed and the stroke of the jack, this being the case until the stops 82, 84, 86 and 88 are stopped by the cross member 90. From that moment on, the continuation of the i J 9 movement of the jack entails the unwinding of the closed chains 66 and 68 in the clockwise direction, so that the ratio between the movement of the carriage 22 and that of the jack 50 is multiplied by four.

4'-

Claims

Machine for piercing a 'shaft furnace taphole, com prising a stand (10) mounted at-the free end of a carrier arm and provided with means of support on the wall of the furnace (16), a device (20) intended for gripping a rod (18) and mounted on a first carriage (22) movable along a second carriage (26), the latter in turn being movable relative to the stand (10) through the action of a hy draulic jack -(50), characteri zed in that the second car riage (26) is provided-with an open chain (36) passing around two return pulleys (38, 40) provided at the oppo site ends of said carriage (26) and having its two ends fastened to said stand (10), in that said first carriage is fixed to said open chain (36), and in that the exten sible part of the jack (50) is connected to the second carriage (26) by two connections, of which one, which acts indirectly with the aid of a step-up device, automatically taking the place of the other, whose action is direct,.

starting from a predetermined position of the second car riage (26).
2. Machine according to Claim 1, characterized by two boxes (60, 62) mounted slidably inside the second carriage (26) and each containing a closed chain (66, 68), these chains being connected along a straight portion to said second carriage (26), in that each of said boxes (60, 62) is connected to the extensible part of the jack (50), and in that the two closed chains (66, 68) are p-6vided with means for immobilization against cross members (90, 92) fastened to the stand (10).
3. Machine according to Claim 1, characterized in that the first carriage (22) is carried by the second carriage (26) by means of running rollers (24).
4. Machine according to any one of Claims 1 to 3, characterized in that the second carriage (26) is essen tially composed of two parallel beams (28, 30) supported by means of running rollers (32, 34) along the two later al sides of the stand (10) and joined at each of their 1 ends by the cross members (38, 40).
5.

1 - 11 carrying said return pulleys Machine according to Claim 2, characterized in that the two boxes (60, 62) are disposed one on each side of the open chain (36) and are carried by running rollers (63) on the inside flanks of each of the beams (28, 30) of the second carriage (26).
6. Machine according to Claim 5, characterized in that each closed chain (66, 68) passes around two return carried by each box (60, 62), one of each pair of being mounted in a movable stirrup (74) associ- pulleys pulleys ated
7. Machine according to Claim 1, characterized in that at least one end of the open chain (36) is fastened to the stand (10) by means of a tensioner (48).

Machine according to Claim 2, characterized in closed chains (66, 68) and the open chain (36) with chain tensioning means (76).
8.

that the are Galle type chains.
9. Machine accordi that the hydraulic jack boxes (60, 62), in that against the stand (10), connected to each of the
10. Machine according t6 Claim 2, characterized in that said immobilization means consist of two pairs of stops (82, 84) and (86, 88) fixed respectively at deter mined points on each side of the top strands of the closed chains (66, 68).
11. Machine according to Claim 10, characterized in that the positions of the stops (82, 84) and (86, 88) on the chains (66, 68) are adjustable.
12. Machine for piercing a furnace taphole, substantially as described with reference.to the accompanying drawings.

ng to Claim 2, characteri (50) is disposed between the end of its rod (52) and in that its cylinder boxes (60, 62).

zed in the two b e a r s (58) i PublIshed 1988 at The Patent Office, State House, 66f71 High Holborn, London WC1R 4TP. Further copies may be obtained from The Patent Office, Sales Branch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by Multiplex techniques ltd, St Mary Cray, Kent. Con. 1,87 owes nranen, oz zaary uray, urpirigDon, iicilT, isno onii. rnnwa cy iiauiTapiex Tecnmques ltd, St Mary Crav, Kent. Con. 1,87