Clay Guns For Blast Furnaces

Abstract

Improved devices for plugging blast furnaces tapholes, the devices including clay gun means for injecting plugging mud into the taphole, are disclosed. The plugging devices are each characterized by a clay gun which effectively forms one side of a parallalogram-type linking. Movements of the plugging devices are controlled by a hydraulic drive and the guns are moved between rest and work positions along a curved path in a plane inclined from the vertical.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the tapping of blast furnaces. More specifically, this invention is directed to apparatus for plugging the taphole of shaft furnaces and particularly blast furnaces. Accordingly, the general objects of the present invention are to provide novel and improved methods and apparatus of such character.

2. Description of the Prior Art

While not limited thereto in its utility, the present invention is particularly well suited for use in removably plugging a taphole of a blast furnace. Such plugging devices, known in the art as "clay guns," have conventionally been suspended from a jib or arm rotating about a vertical supporting column. In the prior art the clay gun is brought into position vertically over the taphole by rotating the supporting column and slewing the device about the jib. The prior art devices further include means for rectilinearly moving the clay gun into its working position in front of the taphole.

Another form of prior art taphole plugging apparatus employs a supporting column inclined from the vertical. The clay gun is rectilinearly slidable on a carriage and the guide rails thereof are rigidly fixed on the outer end of a jib. In this second type of prior art plugging apparatus the clay gun is brought directly vertically over the taphole, by rotating the jib about the supporting column, and slewing of the gun on the jib is unnecessary.

A taphole plugging machine in which the clay gun is carried on a jib rotating on a vertical column and slewably supported therein in two different planes is also known in the prior art. In this further type of prior art device the clay gun is brought into working position by rotating the jib on the vertical column while simultaneously tilting the clay gun on the jib in the two planes.

In the prior art taphole plugging devices either at least three different rotary or slewing motions or at least one rectilinearly sliding motion are required to bring the clay gun into its working position in front of the taphole of the shaft furnace. The rotation or slewing of the clay gun is universally achieved by electric drive means having a pinion gear which engages a toothed rim on the free end of the supporting column.

In all known taphole plugging apparatus the supporting column and associated jib, together with the drive means, necessarily must be of a substantial minimum height. In addition, the apparatus must be located at the edge of the troughing for molden iron so as to be as close as possible to the taphole. The location and extensive area occupied, due in part to the required comparatively large jib swing, by prior art taphole plugging apparatus considerably hampers the execution of work in the vicinity of the taphole. The inconvenience posed by prior art taphole plugging apparatus is particularly noticeable in the case of modern, high-duty blast furnaces which usually have a number of tapholes disposed around the circumference of the furnace hearth. Modern large blast furnaces with a high daily output cannot be put out of operation for lengthy periods for repairing or exchanging parts, such as tuyere and blast connections, which are exposed to abrasion and susceptible to thermal damage. Consequently, it becomes necessary to make these components particularly accessible in order to guarantee proper maintenance during the operation of the furnace. In the interest of accessibility it is desired to provide, around the hearth, a servicing and maintenance platform accessible to small trucks usually needed for the execution of maintenance work. The presence of a plurality of tapholes around the circumference of the blast furnace and the prior art taphole plugging apparatus associated with each taphole is a substantial impediment to the above noted accessiblity requirement since the plugging apparatus has previously prevented the provision of a continuous maintenance platform. This, in turn, creates the further disadvantage that the furnace components particularly susceptible to thermal damage will not be shielded by the maintenance platform during the teeming of the heat or the slag run.

A further disadvantage of prior art clay guns resides in the manner in which the gun is directed upon and pressed into the taphole. In modern high-duty blast furnaces, and particularly those using a high counter pressure at the furnace throat, the molden metal flows out of the taphole at high pressure. To insure proper plugging of the taphole it is, accordingly, necessary to press the clay gun against the taphole with considerable force. The applied pressure during plugging should be elastic in order to provide compensation for any pressure fluctuations occurring in the furnace as well as any reactive pressure at the taphole such as may arise from deflection of the contact area. Further, an elastic application of clay gun nozzle pressure is intended to insure that the clay gun remains firmly held against the taphole so that lateral leakage of the sealing mud is prevented. These requirements, however, have not been adequately met by prior art taphole plugging machines.

SUMMARY OF THE INVENTION

The present invention overcomes the above-briefly discussed and other deficiencies and disadvantages of the prior art by providing novel techniques and apparatus for plugging the tapholes of shaft furnaces. Accordingly, the principle object of the present invention is to eliminate the inherent disadvantages of prior art taphole plugging devices and to provide a taphole plugging machine characterized by very low structural height when compared to existing devices of like character in order that the introduction of the clay gun into the taphole can be performed below the level of the maintenance platform of a blast furnace.

A further significant object of the invention is to design the driving and locating means for a taphole plugging apparatus in such a manner that the clay gun can be brought from the rest to working position with the fewest number of and least complicated movements. This object is achieved while the inserting and withdrawing mechanism is arranged to perform a minimum number of rotary and slewing movements in order to assume a firm and rigid working position while the actuating and holding means provides an elastically-yielding high holding pressure.

In accordance with a preferred embodiment of the invention, a clay gun is rotably mounted on the free end of a jib which incorporates a substantially parallel-motion or pseudo-parallelogram linkage; the plane in which the jib travels from the rest into the working position being inclined from the vertical. The long sides or arms of the distorted parallelogram linkage, in accordance with the present invention, are formed by a main supporting arm and a control bar. The other sides of the linkage are defined by a fixed link and a connecting link. The fixed link is attached to a cylindrical pivot or column inclined from the vertical and mounted on a base plate or frame. The main supporting or carrier arm and the control or guide arm or bar are rotably attached by pins to the fixed link. The connecting link is similarly rotably attached by pins at opposite ends of the supporting arm and the control arm respectively. This arrangement produces the above-mentioned form of parallel motion or pseudo-parallelogram linkage in the jib; the linkage consisting of one fixed end link and three movable side links, all of which are movable in the same plane.

Also in accordance with the invention, the slewing and pressing of the clay gun against the taphole is effected by a hydraulic piston drive which acts directly on the main carrier arm of the jib. In one embodiment of the invention the hydraulic piston drive is constructed as a double-acting hydraulic power cylinder which, when the clay gun approaches the taphole, acts as a differential-pressure drive in order to obtain a quick approach action. The same arrangement, when applying the clay gun to the taphole, works as a single-acting power cylinder since substantially higher closing and holding pressures are required.

During operation of the present invention, as the clay gun approaches the taphole, the nozzle of the gun is caused to move along a predetermined curved path lying in the plane inclined from the vertical. This results in the gun making contact with the taphole when accurately in line with the center line of the taphole. The curved path followed by the moving clay gun is determined by the length ratio of the jib arms forming the movable sides of the distorted or pseudo-parallelogram linkage. Compensation for any lateral displacements of the taphole which may occur is easily achieved by changing the length of the control arm. If required, a vertical adjustment of the device of the present invention can easily be obtained by raising or lowering the entire jib assembly; i.e., by means of a hydraulic drive.

If the particular application of the invention requires that the clay gun be rotated from its working position to a rest position 180.degree. or more removed from the working position, the rest position thus being located as far as possible from the iron or slag troughing, in accordance with a further embodiment of the invention the hydraulic piston drive acts on a rotable intermediate member which may take the form of an articulated lever rather than acting directly upon the main supporting arm of the pseudo-parallelogram jib.

In accordance with yet another embodiment of the invention the entire hydraulic drive is removed from the vicinity of the blast furnace to a location not exposed to the rigorous working conditions at the furnace. The hydraulic piston drive is supplied by pressure pipes leading to the fixed part of the taphole plugging machine and thence to hollow trunnions of novel design and, through these trunnions, to the drive piston. Similarly, the hydraulic drive of the clay gun is supplied with hydraulic fluid through the novel trunnions or rotary joint pivots and shielded pipes leading along the main carrier arm of the jib thereby eliminating hose connections which would be exposed to the high temperatures in the vicinity of the furnace.

The remote location of the hydraulic equipment in accordance with the invention precipitates the further advantage that a number of taphole plugging machines may be supplied from a single hydraulic control unit.

An additional advantage of the invention is derived from the ability to employ hydraulic accumulators of sufficient capacity to enable the apparatus to be operated in case of a failure of the hydraulic pressure source since, in contradistinction to the prior art, the present invention employs no electrically-operated elements.

BRIEF DESCRIPTION OF THE DRAWING

The present invention may be better understood and its numerous objects and advantages will become apparent to those skilled in the art by reference to the accompanying drawing wherein like reference numerals refer to like elements in the several figures and in which:

FIG. 1 is a diagrammatic plan view of the parallel-motion or pseudo-parallelogram linkage jib of a taphole plugging machine according to the invention, the paths of motion of the clay gun from its resting position into its working position being shown;

FIG. 2 is a diagrammatic view of a mechanism for providing compensation for horizontal displacements of the taphole position in accordance with the invention;

FIG. 3 is a plan view of a first embodiment of a taphole plugging machine in accordance with the present invention;

FIG. 4 shows a side elevation of the taphole plugging machine of FIG. 3;

FIG. 5 is a diagrammatic view of a mechanism for providing compensation for vertical positional displacements of the taphole in accordance with the invention;

FIG. 6 shows a rear view of the taphole plugging machine of FIG. 3;

FIG. 7 is a cross-sectional view of a novel rotary pressure-fluid admission device in accordance with the invention;

FIG. 8 is a diagrammatic view of the pseudo-parallelogram linkage jib illustrating the paths of motion of the clay gun while slewing through 180.degree. from the resting into the working position;

FIG. 9a is a top view of a second embodiment of the taphole plugging machine in accordance with the present invention, FIG. 9a depicting the clay gun in front of the taphole;

FIG. 9b is a top view of the taphole plugging machine of FIG. 9a in the resting position;

FIG. 10 shows one part of the articulated lever drive mechanism of the taphole plugging machine of FIGS. 9a and 9b; and

FIGS. 11, 12, 13, 14 and 15 a schematic illustration of examples of hydraulic control systems in accordance with the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The mode of operation of the pseudo-parallelogram linkage jib according to the invention is depicted in FIG. 1. FIG. 1 shows a clay gun 1 intended to be applied by a jib 2 against a taphole 8 in the wall 9 of a blast furnace over a tap spout 7. The jib 2, which in the interest of clarity is shown diagrammatically, substantially consists of a main supporting or carrier arm 3, a fixed leg or link 4, a control or guide arm 5 and a connecting link 6. As is apparent from the drawing, these four elements form a virtual parallel-motion linkage jib 2 with four link joints A, B, C and D. The two joints A and B of the pseudo-parallelogram linkage jib 2 are the fixed pivots of the carrier arm 3 and control link 5 respectively. As will be explained hereinafter, the pivot point A is formed by a fixed supporting column 19 (FIG. 3) inclined from the vertical. The joint C determines the suspension point of the clay gun 1 which is at that point rotatably attached in the plane of the virtual parallel-motion system to the end of the carrier arm 3. The joint D of the virtual parallel-motion system 2 forms the point of application of the control or guide arm 5 to the clay gun 1. The control link 5 is rotatable on the pivot 61 (FIG. 6), located at the joint D and connected with the clay gun 1, with respect to the latter.

FIG. 1 shows, in full lines, the clay gun 1 and the carrier arm 3 in the working position in front of the taphole 8, whereas the resting position is indicated by broken lines and an intermediate position by dot-dash lines. In the above three positions identical components are designated by identical reference numerals provided with appropriate indices in the intermediate and in the resting positions.

As will be seen from FIG. 1, during the approach of the clay gun 1 from its resting position to its working position the joints C and D travel along circular paths E and F having their centres at A and B. Simultaneously, the clay gun mouthpiece or nozzle moves along the curved path G while the rear end or breech of the gun describes the curve H. The curved motion path G of the clay gun mouthpiece is, as may be seen from the FIG. 1, not circular, but exhibits a shape which in the vicinity of the taphole 8 is to the extent possible tangential to the centreline of the taphole. In other words the clay gun mouthpiece swings or slews at some particular greatest possible distance from the taphole 8 into line with the tapspour runner 7 and thence, within that runner 7, moves almost perpendicularly towards the taphole 8.

The motion path G of the clay gun mouthpiece can be adapted to the most suitable shape for prevailing space conditions at the blast furnace by varying the geometry of the pseudo-parallelogram linkage system. For this purpose either length ratios of the different sides of the virtual parallelogram, i.e., the lengths of the carrier and control arms 3 and 5 respectively, and the corresponding connecting links 4 and 6 and/or the relative positions of the link joints A, B, C and D can be altered. Care must be taken that, as already mentioned above, the clay gun mouthpiece approaches the taphole to the extent possible perpendicularly thereto; that the lateral deviations of the clay gun mouthpiece during the longest possible length of approach and withdrawal respectively do not jut out the tapping runner or spout; and that the resting position of the clay gun is as far away as possible from the said runner.

FIGS. 3, 4 and 6 show a preferred embodiment of a taphole plugging machine in accordance with the present invention. The carrier arm 3 is rotatably supported on a fixed column or post 19 which, as shown in FIG. 4, is inclined from the vertical. The angle of inclination of the column 19 from the vertical is preferentially selected so that its centre-line is perpendicular to the centreline of the taphole. The column or post 19 is secured on a base or ground frame 16. The link 4 is attached to the column 19. The free end of the carrier arm 3 carries the clay gun 1 by means of a fork 24 pivoting on the carrier arm 3 (FIGS. 4 and 6). The control arm 5 is rotatably attached, at the link joint B, to the fixed link 4 by a pin 60 and secured by a further pivot pin 61 on the rear or breech end of the gun 1. The length of the control arm 5 can be varied by means of an adjusting device, for example, a turnbuckle 11. As shown in FIG. 2, this allows the position of the link joint D to be continuously changed between the two end positions 12 and 13, thereby continuously changing the end position of the clay gun mouthpiece within the range bounded by the lines 14 and 15. Compensation for horizontal straying or migration of the taphole centreline 1 in the blast furnace wall 10 can be easily achieved by this means.

To compensate for vertical displacements of the taphole, the clay gun 1 is rotatably suspended by the pivot pins 27 and 27' in the fork 24 as shown in FIGS. 4 and 6. The fork 24 is so designed that the clay gun 1 can at its rear end be again supported by adjustable bolts 25 - 25'. As will best be seen from the diagrammatic representation in FIG. 5, the longitudinal axis of the clay gun can be rotated about the suspension points 27 - 27' by varying the elevation adjustment of the attachment points 28 - 28' by means of set screws 26 - 26'. The mouthpiece of the clay gun 1 can accordingly be adjusted between the two end positions indicated at 29 and 30 and adapted to the actual vertical position of the taphole 8. FIG. 5 further shows diagrammatically the manner in which the fork 24 is rotatably suspended from the carrier arm 3 in order to enable the clay gun to be slewed about the point C within the plane of the virtual parallelogram.

In blast furnaces provided with an emergency taphole at a certain height above the normal taphole and corresponding runner, it may become desirable to be able to plug this emergency taphole also, although only exceptionally used, by means of the same taphole plugging machine. Such emergency tapholes are usually located from 1 to 1.5 meters above the normal taphole. If plugging of the emergency taphole is desired, the rear of the ground frame is equipped with a horizontal spindle about which the whole structure of the taphole plugging machine can be rotated to allow the virtual parallelogram linkage to be continuously adjusted until the clay gun mouthpiece butts against the said emergency taphole.

In accordance with the invention, and as may best be seen from FIGS. 3 and 6, the driving means of the pseudo-parallelogram link jib 2 comprises a hydraulic power cylinder 20 with a corresponding piston rod or plunger 21. The hydraulic cylinder 20 is rotatably secured by swivel pivots 22 between two framework discs 17 and 17'. The two discs or plates 17 and 17' are respectively supported by a pivot pin 18 attached to the ground frame 16 and by the fixed post 19. As already mentioned, column 19 and pin 18 are inclined from the vertical. The pivot pin 18 is intended to receive the reactive forces set up when plugging the taphole, which are equally distributed between the two plates 17 and 17', in order to eliminate as far as possible the bending forces acting on the column 19.

The piston rod 21 acts, at points 23, on the carrier arm 3 through the intermediary of a pin 62 held between two lugs 63. Since the hydraulic cylinder 20 is rotatably attached to the fixed pivot 22, the motion of the piston rod slews the carrier arm 3 about the column 19 (at point A) and with it the control arm or guide link 5 swinging about the pin 60 (at point B) while the clay gun mouthpiece describes the curve G as explained in the discussion of FIG. 1.

The double-acting hydraulic cylinder 20 is operated as a differential piston when moving the clay gun into the working position in order to obtain a quick advance of the clay gun with a relatively small pressure-fluid feed. When pressing the clay gun against the taphole the hydraulic cylinder is connected to act as a direct pressure cylinder to continuously maintain a high working pressure. Contrary to the electric drives hitherto used, the described hydraulic system provides an electric control of the working pressure whereby the pressure fluctuations at the taphole are automatically compensated.

The delivery of pressurized fluid to the hydraulic cylinder 20, as well as to the hydraulic drive of the mud piston of the clay gun, is performed by a novel rotary fluid-admission device. FIG. 7 shows a rotary pressure-fluid admission valve 33 for the in- and outflow of the hydraulic pressure-fluid to the working cylinder of the clay gun.

As noted above, the clay gun 1 is suspended on the two shanks 31 and 32 of the fork 24. Fork 24 is rotatably linked, by means of roller bearings 38, 39 with the main slewing carrier arm 3 of the distorted parallelogram linkage jib 2. In order to overcome the reactive forces developed when the clay gun is pressed against the taphole, bearings 38, 39 are conical roller bearings. A shown in FIG. 7, bearings 38, 39 are mounted in such a manner that the length of the bearing line is appreciably greater than the offset distance when compared with the same ratio when non-conical bearings are used. In the case of non-conical bearings the ratio of bearing-line length to offset distance would be represented in FIG. 7 by the distances x' and y', which would result in a construction of far larger dimensions for absorbing the resultant reactive forces and consequently imply an undesirable enlargment in height of the fork head.

The fork 24 has an internal bore 40 which receives the casing 41 of the rotary pressure-fluid admission valve 33. The internal bore of the casing 41 in turn receives a pivot pin 42 supported at both sides in roller bearings 34, 34' inside the casing 41. Casing 41 is further provided with annular grooves 35 and 36 which respectively communicate with fluid admission holes 49 and 50 disposed on the periphery of casing 41.

The fork 24 further contains pressure-fluid ducts or passages 44 and 45 which respectively communicate with the grooves 35 and 36. Packing rings 37, arranged around the grooves 35 and 36 within the rotary pressure-fluid admission valve casing 41, seal the passages between the fork 24 and the said rotary pressure-fluid admission valve casing 41. Admission and discharge of the pressure-fluid takes place through channels 46 and 47, respectively arranged within the pivot pin 42 and the head 48 thereof, the passages 49 and 50 and the slotted grooves 35 and 36. The passages between the pivot pin 42 and the casing 41 are sealed by packing rings 52 held in place by spacer members 53. These spacers 53 have a number of peripheral openings for the passage of the pressure-fluid. The pivot pin 42 and the casing 41 can further be fitted in the appropriate places with additional circumferential grooves in order to increase the free cross-section available for the passage of the pressure-fluid at these places.

The inflow and outflow of the pressure fluid to and from the rotary pressure-admission valve element 33 is effected respectively by pressure pipes 55 and 56 housed within the main supporting arm 3. From these inlets and outlets respectively the pressure-fluid is conducted through the passages 46 and 47 respectively, the bores in the spacers 53 and the passages 50 and 49 respectively, to the annular grooves 36 and 35 to the channels 45 and 44 respectively. The fluid is delivered by rigid or flexible, usually very short, pressure pipes or hoses, to the clay gun actuating cylinder from channels 45 and 44.

The novel rotary pressure-fluid admission valve of FIG. 7, being disposed inside the fork, considerably reduces the structural height of jib 2. A similar rotary pressure fluid admission valve system is arranged at the pivot point A on the jib. The connecting conduits between the individual, rotary pressure-fluid admission valves are rigid pipe elements which require far less space than flexible hose connections and can readily be shielded from the high ambient temperatures; thus being far less susceptible to disturbing influences than the conventional hose connections of the prior art.

FIGS. 8, 9a, 9b and 10 show an embodiment of the taphole plugging machine according to the invention which enables slewing the clay gun about an arc of 180.degree. from its working position to its resting position.

The apparatus shown in FIG. 8 comprises, similarly to the embodiment of FIG. 1, a clay gun 1 which is approached to and held against the taphole 8 in the blast furnace wall 9 over a spout or iron runner 7 by mean of a jib 2. The jib 2 is shown diagrammatically, and is mainly constituted of a main carrier arm 3, a link 4, a guide arm or control arm 5, and a connecting link 6. The arms 3 and 5 and the links 4 and 6 form the virtual parallel-motion linkage system or pseudo-parallelogram with the four corner points or joints indicated at A, B, C and D. The two joints A and B of the virtual parallel-motion link jib 2 form fixed pivots for the carrier arm 3 and control arm 5 respectively. The joint C provides a suspension point for the clay gun 1 which is rotatably attached on the carrier arm 3. The joint D of the jib 2 forms the rotatable pivot point of the control arm 5 on the clay gun 1.

FIG. 8 shows the clay gun 1 and carrier arm 3 in the working position in front of the taphole 8 in full lines, while the resting position is shown in broken lines; identical component parts being indicated by identical reference numerals provided with the appropriate indices.

In the resting position shown in FIG. 8 the clay gun 1 has been slewed through 180.degree. about the two fixed points of the pseudo-parallelogram jib 2 and away from its working position in front of the taphole 8. The pivot points C and D describe circular motion paths E and F, respectively, and the clay gun mouthpiece moves along the curved motion path G and its rear end or breech, along the curve H. The path of the curve G is so adjusted that the clay gun mouthpiece slews into position in front of the taphole 8 as far as possible tangentially to the centreline thereof.

Since the clay gun has been slewed through 180.degree. about the fixed point A, the two longitudinal side arms 3 and 5 of the pseudo-parallelogram jib 2 must necessarily become crossed. In order to effect this crossing of the pseudo-parallelogram arms the hydraulic drive must act on the main carrier arm 3 of the pseudo-parallelogram linkage jib through an intermediate connecting link.

FIGS. 9a and 9b show one embodiment of the driving arrangement according to the invention; FIG. 9a showing the working position and FIG. 9b the resting position of the taphole plugging machine. In the resting position identical elements of the machine are designated by the same reference numerals, with the appropriate indices, as those used in the representation of the working position. As shown in FIGS 9a-9b, the carrier arm 3 is rotatably mounted on fixed supporting column or post 19. The column 19 is preferably somewhat inclined, or inclinable from the vertical; and is fixed to ground frame 16. The control arm 5 is rotatably secured by means of a pivot pin 60, to a shank (not shown) affixed to the column 19. The free ends of the arms 3 and 5 are linked, for instance as described with reference to FIGS. 1 to 6, with the clay gun 1.

The actuating means of the pseudo-parallelogram linkage jib 2 include a hydraulic power cylinder 20 whose piston rod 21 is held, by means of a rotatable crosshead 81, between a pair of mutually parallel bearing plates 17 and 17'; only plate 17' being shown in FIGS. 9a-9b. The two bearing plates 17, 17' are supported by a rotatable pivot pin or trunnion 18 on the ground frame 16 and by the column 19. The trunnion 18 serves to absorb the reactive moments set up during the plugging operation.

The hydraulic cylinder 20 acts on a U-shaped stirrup 82, suitably at the middle thereof, by means of pivot pins 83. The U-shaped stirrup 82, preferably executed as a double stirrup having the hydraulic cylinder 20 disposed between the two stirrup plates, is rotatably connected to the bearing plates 17 and 17' by means of a fixed pivot pin 84. The free end of the stirrup 82 is rotatably connected to an arm 85 by means of a further pivot pin 86. Arm 85 is linked with the carrier arm 3 by means of another pivot pin 87. The fluid feed to the hydraulic drive is arranged on the outer end of the piston rod or plunger 21, which passes through the crosshead 81, by means of short hose connections which require little freedom of motion. An alternative possibility for supplying pressure fluid to the piston rod 21 is to provide for a rotary pressure-fluid admission valve element in the axis of rotation of the crosshead 81. Pressurized fluid is supplied to the hydraulic cylinder 20, which is of the double-acting type, by internal passage in the piston rod 21.

The movement of the taphole plugging machine from its resting position into its working position and vice-versa, and the forces acting on the different points of application in the carrying and slewing device, may best be seen from FIG. 10 which shows the motions of the stirrup 82 during the approach and withdrawal of the clay gun 1 from and to the taphole 8. In FIG. 10 the working position of the carrying and slewing device or frame is shown in full lines while the resting position is represented in broken lines. Similarly the individual components of the taphole plugging machine are shown in the resting position with the same reference numerals but with appropriate indices.

While slewing the taphole plugging machine from its resting position into its working position, the piston rod 21 is forced outwardly with respect to cylinder 20. Since the piston rod 21 is secured to the fixed pivot 81, the point of attack 83 of the cylinder 20 on the stirrup 82 is moved along the circular path K. The centre of rotation of the curved path K is determined by the fixed pivot pin or bolt 84. Simultaneously the point of attack 87 of the carrier arm 3 rotates in a path L about the column 19 or the fixed pivot point A, while the point of attack 86 of the movable connecting link 85 moves along the circular path M, whose centre of rotation is likewise at the bolt 84.

During these motions the centreline of the hydraulic power cylinder will have moved from its starting position 0' into the position 0. Similarly, the angle .alpha. formed by the centerline of the link 85 and the line P connecting the fixed point 84 with the pivot point 86, will assume a succession of different values and attain preferably its least value when the clay gun has assumed its working position. This ensures that the force necessary to press and hole the clay gun against the taphole, which may attain a value of 20 tons or more, is appreciably reduced by the action of the above described toggle mechanism so that the hydraulic drive is not required to withstand the whole pressure load. In this way the required driving force to produce the required contact pressure can be much less than in case of direct action of the hydraulic drive on the carrier arm 3. It will therefore be of advantage to design the articulated lever system formed by the stirrup 82 and the link 85 in such a manner that in the working position of the clay gun the angle .alpha. has its smallest possible value.

As will be seen from FIG. 10, the point 87 rotates through 180.degree. about the fixed point A during the slewing motion of the device so that in its resting position the clay gun is turned 180.degree. away from its working position. It is, of course, possible to design apparatus in accordance with the invention in such a manner that, depending on the space conditions at the furnace, the angle through which the clay gun is slewed is greater or less than 180.degree. .

FIGS. 11 to 15 represent various embodiments of the hydraulic control system for the taphole plugging machine according to the invention. In these figures the conduits for supplying the hydraulic pressure fluid to the working cylinder 20 of the jib 2 are designated by numeral 70, while the conduits for supplying pressurized fluid to the cylinder of the clay gun are indicated by numeral 71. For the sake of clarity the pressure fluid conduits 71 are shown as leading directly to the clay gun. In practice these conduits pass through the novel rotary pressure-fluid admission valves 33 described above with reference to FIG. 7.

FIG. 11 shows a simple layout in which the pressurized fluid is drawn directly from a storage tank pumping unit located in a hydraulic plant 72 and delivered through a regulating and control desk 74 to the taphole plugging machine.

FIG. 12 shows a similar arrangement with a main and central regulating and controlling unit 76 remotely actuating an electro-hydraulic power drive system 78 for supplying pressure fluid to the taphole plugging machine.

FIGS. 13 and 14 show the same installations as in FIGS. 11 and 12, respectively, with the exception that a hydraulic accumulator 80 is connected in series with the tank and pumping unit 72. These installations have the substantial advantage that the power fluid supply can be maintained even should the electric current supply fail, and the operation of the blast furnace can thus be maintained. FIG. 15 shows an installation in which a number of taphole plugging machines are supplied with pressurized fluid from a common tank and pumping unit 72 and a common hydraulic accumulator 80.

While preferred embodiments have been shown and described, various modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustration and not limitation.

Claims

What is claimed is:

1. Apparatus for use in plugging a taphole of a shaft furnace comprising:

clay gun means including a clay gun having a nozzle for injecting plugging material into a furnace taphole;

linkage means including three side members, said linkage means side members cooperating with said clay gun means to define a parallel-motion linkage;

stationary pivot means for rotatably supporting said clay gun and linkage means at the junction of two of said side members of said linkage means;

hydraulic actuator means; and

means for transmitting forces generated by said actuator means directly to one of said linkage means side members intermediate its ends whereby said linkage means may be moved between a rest position and working position and said clay gun will simultaneously be moved from a position remote from the furnace taphole to abutting relationship to the furnace taphole.

2. The apparatus of claim 1 wherein said linkage means comprises:

carrier arm means;

means rotatably suspending said clay gun means from a first end of said carrier arm means;

guide arm means, said guide arm means being pivotally connected at a first end to said clay gun means whereby a portion of said clay gun means defines a side of a parallelogram intermediate said first ends of said carrier and guide arm means; and

fixed position link means for interconnecting the second ends of said carrier and guide arm means, the second end of said carrier arm means and a first end of said fixed link means being interconnected by said stationary pivot means.

3. The apparatus of claim 2 wherein said stationary pivot means comprises:

a support column inclined at an angle with respect to the vertical.

4. The apparatus of claim 3 wherein the means for suspending said clay gun means comprises:

conical roller bearing means for increasing the line of application of reactive forces generated during operation; and

means for connecting said bearing means to said clay gun means and to said carrier arm means.

5. The apparatus of claim 3 wherein the guide arm means of said linkage means includes an elongated guide arm and means for continuously adjusting the length of said elongated guide arm within specified limits so as to adapt the path of motion of the clay gun nozzle to horizontal positional displacements of the furnace taphole.

6. The apparatus of claim 5 wherein said guide arm is attached to said clay gun adjacent the end disposed opposite to the nozzle by means of a pivot pin.

7. The apparatus of claim 3 wherein said clay gun suspending means includes means for slewing said gun about an axis.

8. The apparatus of claim 7 wherein the inclination of the clay gun is adjusted by rotating said gun with said slewing means to readjust said gun to compensate for any vertical positional displacements of the furnace taphole.

9. The apparatus of claim 3 wherein said force transmitting means comprises a rotatable intermediary link member.

10. The apparatus as claimed in claim 3 wherein said force transmitting means comprises an articulated lever.

11. The apparatus of claim 10 wherein said articulated lever includes a U-shaped stirrup and a link arm rotatably connected therewith, said hydraulic actuator means being coupled to the stirrup, said stirrup having a fixed end rotatably engaged with a fixed pivot means and a free end rotatably connected to said link arm, whereby said link arm acts upon said carrier arm means of the linkage means through a rotatable coupling means.

12. The apparatus of claim 3 wherein said hydraulic actuator means includes a double-acting hydraulic power cylinder, said power cylinder being connected for differential pressure operation when positioning the clay gun being connected as single-acting pressure cylinder when said clay gun is in abutting relationship to the taphole.

13. The apparatus of claim 3 further including rotary pressure-fluid admission valve means for supplying hydraulic fluid to said hydraulic actuator means.

14. The apparatus of claim 13 further including hydraulic control and supply means, said control and supply means being located remotely from the vicinity of the furnace.

15. The apparatus of claim 14 further including hydraulic accumulator means connected between said control and supply means and said drive means for supplying fluid to said hydraulic actuator means whereby said hydraulic accumulator means delivers an elastically-yielding holding pressure to said clay gun when in abutting relationship to the taphole to compensate for any fluctuations of pressure during the plugging operation.