Title of Invention	"METHOD OF CONVEYING FURNACE BOTTOM MANTLE FOR BLAST FURNACE"
Abstract	A method conveying a furnace bottom mantle constructing a furnace bottom mantel for a blast furnace in advance at a location other than the blast furnace foundation, installing bricks in the furnace bottom mantel, and conveying the mantel over the blast furnace foundation, wherein the mantel is conveyed while keeping the flexure amount of the top surface of the bricks installed in the furnace down to 3 mm per meter of the mantel radius.

Title of Invention

"METHOD OF CONVEYING FURNACE BOTTOM MANTLE FOR BLAST FURNACE"

Abstract

A method conveying a furnace bottom mantle constructing a furnace bottom mantel for a blast furnace in advance at a location other than the blast furnace foundation, installing bricks in the furnace bottom mantel, and conveying the mantel over the blast furnace foundation, wherein the mantel is conveyed while keeping the flexure amount of the top surface of the bricks installed in the furnace down to 3 mm per meter of the mantel radius.

Full Text	DESCRIPTION METHOD OF CONVEYING FURNACE BOTTOM MANTLE FOR BLAST FURNACE TECHNICAL FIELD The present invention relates to a conveyance method comprising constructing a blast furnace body in advance at a location other than the blast furnace foundation, disassembling the existing furnace body, then conveying the blast furnace on to that foundation, particularly a method of conveying a furnace bottom mantle for a blast furnace which conveys a furnace bottom mantle for a blast furnace, in which bricks have been installed in advance, to the blast furnace foundation. BACKGROUND ART When repairing a conventional blast furnace, the work method of dividing the aged blast furnace (old blast furnace) into small pieces and removing it from the blast furnace foundation, then welding, piece by piece, strip-like shells on the foundation to install a new blast furnace body, then stacking the bricks inside the furnace, in other words, the work method of constructing a new blast furnace from the start, has been adopted. For this reason, with the conventional work method, a long period of time was required for repair; after the installation of the blast furnace body, high elevation work was necessary for attaching the stave cooler and cooling piping and other cooling devices, and problems occurred in regard to safety and construction quality. On the other hand, in recent years, in order to shorten the work period, the practice has been to, in parallel with the operation of the old blast furnace, divide the new blast furnace into a plurality of ring-shaped blocks at a nearby separate location (ground assembly site), start to assemble the blocks all at once, completely remove the old blast furnace from the foundation, then convey these blocks using dollies or other large sized heavy weight transport carts, lifting and install them by a jack, crane, or the like, and weld together the shells, piping, etc. of the parts where the blocks contact each other, that is, the so-called "block work method" has been employed (for example, see Japanese Patent Publication (B2) No. 47-1846, Japanese Patent Publication (A) No. 9-143521, and Japanese Patent Publication (A) No. 10-102778). For example, Japanese Patent Publication (B2) No. 47-1846 discloses the technology of dividing a blast furnace into a furnace bottom, bosh, furnace belly, furnace shaft, furnace opening, and the like, successively moving them in the lateral direction and stacking the divided parts using a mobile scaffold for each part around the blast furnace, connecting the entire assembly to form an integral unit, and thereby shortening the construction period of the blast furnace. As described above, shortening the work period in the repair of a blast furnace has been studied for a long time, but a blast furnace is a large sized structure and a heavy weight object, so actually applying this work shortening work method is difficult. Even now, manufacturers are engaged in various studies and are filing numerous patent applications. For example, Japanese Patent Publication (A) No. 9-143521 discloses a method of repairing and constructing a blast furnace in a short period comprised of the steps of, in the disassembly or rebuilding an existing blast furnace, (a) dividing a furnace body into several ring-shaped blocks from the furnace top to the furnace bottom and constructing them at a location other than the blast furnace foundation, (b) attaching means for preventing warping or strain of the brick stacking part and means for securing circularity to the blocks other than the bottommost furnace bottom block in the ring-shaped blocks, (c) on the other hand, stacking bricks on a furnace bottom plate set at the bottom end to construct the furnace bottom block, (d) conveying the ring-shaped blocks other than the furnace bottom block on to the blast furnace foundation by lateral conveyance, then successively lifting up and joining the blocks from the furnace top using the liftup method, and (e) conveying and installing the furnace bottom block on the foundation by lateral conveyance at the level of the blast furnace foundation level, then joining it with the top blocks. Further, Japanese Patent Publication (A) No. 10-102778 discloses a method of construction of a blast furnace body dividing an existing furnace body of a blast furnace into a plurality of ring blocks from the furnace top to the furnace bottom and dismantling it and fabricating similar ring blocks and assembling the ring blocks on the blast furnace foundation, which method of construction of a blast furnace body comprises installing a hoist apparatus for raising or lowering a ring block of the furnace body at a location other than the blast furnace foundation, transferring the ring block to transport carts carrying a load level adjustment structure so as to match the load level with the blast furnace foundation level, transporting the block to the hoist apparatus, supporting the ring block by the hoist apparatus, then removing the load level adjustment structure, lowering the ring block to the lowest level which the transport cart can carry and transporting it to a placement site by the transport carts, on the other hand constructing the ring block at the lowest level which the transport cart can carry, transporting it to the hoist apparatus by the transport carts, supporting the ring block by the hoist apparatus, lifting it up to a level enabling movement to the blast furnace foundation level, placing it on transport carts carrying the load level adjustment structure matching the load level with the blast furnace foundation level, and conveying it over the blast furnace foundation. The method described in Japanese Patent Publication (B2) No. 47-1846 is a method comprising constructing each divided block on a scaffold of the same height as the assembled finished height, moving each part using the mobile scaffold after completion, and thereby completing the furnace body. By this method, since the height of the blast furnace body is about 100 meters, the furnace body is divided and assembled on the scaffold for each divided height, and the blocks are constructed on the scaffold. Consequently, with this method, even with divided blocks, the weight reaches several thousand tons. A scaffold having a rigidity which can withstand this weight is necessary. Further, since this scaffold is necessary for each divided block, the fabrication cost of this scaffold becomes high. In the end, this method was never realized. In the method described in Japanese Patent Publication (A) No. 9-143521, the ring-shaped blocks of a furnace body are moved over the blast furnace foundation, lifted up, and joined. Finally, the furnace bottom block is moved and the rings are placed over and joined with the furnace bottom block to complete the furnace body. At this time, the furnace bottom block is built up by stacking bricks on the furnace bottom plate. However, the furnace bottom of a blast furnace has a diameter of as much as 10 to 20 meters. When stacking bricks on the furnace bottom plate, the deformation of the furnace bottom plate is the most important problem, but the above publication does not disclose this important problem and means for its solution. Therefore, while there was the idea of stacking bricks at a furnace bottom block, specifically how to solve the above problem is still a pending issue among the concerned parties. This method has not yet been realized in practice. Further, Japanese Patent Publication (A) No. 10-102778 discloses installing a hoist apparatus which raises and lowers a ring block of a furnace body at a location other than the blast furnace foundation and moving the ring block to the blast furnace foundation by transport carts carrying a load level adjustment structure so as to match the load level to the blast furnace foundation level, but does not disclose the advance installation of bricks to the blocks of the furnace body. In this way, the block work on a blast furnace is technology essential for shortening the work period, but the more advanced the block work, the greater the weight of each block and more sophisticated the conveyance technology required. The above patent publications do not describe such conveyance technology. DISCLOSURE OF THE INVENTION The present invention was completed as a result of intensive studies by the present inventors to solve the above problems and has as its gist the following. (1) A method of conveyance of a furnace bottom mantle for a blast furnace constructing a blast furnace bottom mantel in advance at a location other than a blast furnace foundation, installing bricks at said furnace bottom mantel, and conveying it over the blast furnace foundation, said method of conveyance of a furnace bottom mantle characterized by conveying it while keeping the flexure amount of the top surface of the bricks installed inside the furnace to 3 mm or less per meter of the mantel radius. (2) A method of conveyance of a furnace bottom mantle for a blast furnace according to (1) characterized by installing balance beams with a thickness A of 700 mm to 2200 mm at a bottom surface of said furnace bottom mantel. (3) A method of conveyance of a furnace bottom mantle for a blast furnace according to (1) characterized by installing laying beams with a thickness H of 480 mm to 1000 mm at a bottom surface of said furnace bottom mantel and installing balance beams with a thickness A of 700 mm to 2200 mm at a bottom surface of said laying beams. (4) A method of conveyance of a furnace bottom mantle for a blast furnace according to (2) or (3) characterized by connecting dollies in the longitudinal direction to form a plurality of dolly trains, pulling in the dolly trains in parallel in the clearance formed between said balance beams and the ground surface, and arranging the dolly trains while reducing their lengths the further from the center line to the end lines. (5) A method of conveyance of a furnace bottom mantle for a blast furnace according to any one of (2) to (4) characterized by making the shapes of balance beams shapes according the lengths of the dolly trains drawn in. (6) A method of conveyance of a furnace bottom mantle for a blast furnace according to any one of (4) or (5) characterized by arranging the dolly trains in parallel so that the distance P between hydraulic cylinders set at said dollies becomes within 2.5 m. (7) A method of conveyance of a furnace bottom mantle for a blast furnace according to any one of (1) to (6) characterized by installing a laser transmitter at any position of a top surface of bricks installed at said furnace bottom mantel, similarly arranging a plurality of laser receivers in a line at any position of the top surface of the bricks, and conveying the furnace bottom mantel while measuring the flexure amount of the top surface of the bricks obtained by detecting amounts of displacement of the laser received in the vertical direction. (8) A method of conveyance of a furnace bottom mantle for a blast furnace according to (7) characterized by using the amount of vertical displacement detected by said laser receivers to make corrections canceling out the error generated by the slant of the laser transmitter caused by flexure of the top surface of the bricks so as to make the amounts of vertical displacement after correction the true flexure amount. According to the present invention, even a furnace bottom mantel at which bricks have been installed in advance at a location other than the foundation of the blast furnace and thereby increased in weight can be stably conveyed onto the blast furnace foundation without joint breakage etc. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view explaining an outline of a blast furnace. FIG. 2 is a view showing an outline of the installation of a furnace bottom mantel according to the present invention. FIG. 3 is a view explaining an outline of an experimental mini model. FIG. 4(a) is a view schematically showing a planar structure of laying beams. FIG. 4(b) is a view showing the cross-sectional structure of laying beams. FIG. 5 is a view showing the relationship between the thickness of the laying beams and the flexure amount. FIG. 6 is a view schematically showing the cross-sectional structure of balance beams. FIG. 7 is a view showing the relationship between the thickness of balance beams and the flexure amount. FIG. 8(a) is a view showing a furnace bottom mantel in which bricks are installed at a ground assembly site. FIG. 8(b) is a view showing a furnace bottom mantel conveyed by dollies. FIG. 8(c) is a view showing a furnace bottom mantel conveyed using air casters. FIG. 9(a) is a view showing a layout of dollies according to the present invention. FIG. 9(b) is a view showing a conventional layout. FIG. 10(a) is a view showing an example of a mode of installation of a reinforcing ring. FIG. 10(b) is a view showing the reinforcing ring expanded. FIG. 11(a) is a view showing an example of a mode of installation of stays. FIG. 11(b) is a view showing the stays expanded. FIG. 12 is a view showing an example of a layout of air casters. FIG. 13(a) is a view showing an example of a layout of a laser transmitter and laser receivers. FIG. 13(b) is a view showing the flexure amount of the top surface of the bricks. FIG, 14 is a view showing the error caused by slant of a laser transmitter caused by flexure of top surface of the bricks. FIG. 15 (a) is a view showing another example of a layout of a laser transmitter and laser receivers. FIG. 15(b) is a view showing another example of a layout of a laser transmitter and laser receivers. FIG. 16 is a view showing a method of correction canceling out error generated due to slant of the laser transmitter caused by flexure of the top surface of the bricks. FIG. 17 is a view explaining the technological significance of setting a measuring device on the top surface of bricks installed in a furnace bottom mantel. BEST MODE FOR CARRYING OUT THE INVENTION Below, referring to FIG. 1 to FIG. 17, the best mode for carrying out the present invention will be explained. As seen in FIG. 1, a blast furnace is disassembled and repaired by cutting a furnace body 2 of the blast furnace in the horizontal direction to separate it into a plurality of sections in the vertical direction and removing them from the blast furnace foundation 5 to outside the blast furnace foundation. On the other hand, the furnace body 2 to be newly installed is constructed by a number of blocks set in advance at a location than the blast furnace foundation (ground assembly site) . FIG. 2 is a view showing the state when conveying the furnace bottom mantel 1 divided into blocks and constructed at the ground assembly site. At the ground assembly site where the furnace body is constructed in advance, balance beams 16 are set at the ground surface. On the top surfaces of the balance beams 16, laying beams 12 are placed. Between the laying beams 12 and the balance beams 16 are installed air casters 18 for making the laying beams float up. The furnace bottom mantel 1 is constructed on the top surfaces of the laying beams 12 configured in this way. Note that FIG. 4 and FIG. 12 show one example of the layout of the air casters 18, but the method of arrangement of the air casters 18 is not limited to this. Explained in detail, the shell 7 is placed standing on the furnace bottom plate 6, the stave cooler 8 is laid on the inside of the shell 7, and the hearth bricks 9 are installed via the joint filling material 11 on the top surface of the furnace bottom plate 6. Then, carbon bricks 10 are installed on the top surface of the hearth bricks 9 via a joint filling material. In this state, the weight of the furnace bottom mantel 1 becomes approximately 1000 tons or more. To construct this furnace bottom mantel 1 on the balance beams 16 set at the ground assembly site, it is necessary to give rigidity to the balance beams 16 to prevent deformation of the furnace bottom mantel. However, there was never any technology disclosing specifically what to do to prevent deformation of the furnace bottom mantel. Therefore, the present inventors engaged in repeated numerical analyses and experiments by the finite element method and as a result obtained the discovery that if conveying the furnace bottom mantel 1 while keeping the flexure amount per meter of the mantel radius down to 3 mm at the top surface of the carbon bricks 10 installed on the furnace bottom mantel 1, it is possible to place it on the blast furnace foundation and use it as it is. In experiments, as shown in FIG. 3, a mini model obtained by installing hearth bricks 9 on a furnace bottom plate 6 via a stamp material 25 and installing carbon bricks 10 on the top surface of the hearth bricks 9 via a stamp material 25 was employed. As shown in FIG. 3, jacks 24 were placed at the bottom of the furnace bottom mantel of the mini model, the jacks were operated, and the state of gaps with the joints and stamp material 25 installed between the carbon bricks was observed. The results are shown in Table 1. Table I. Relationship of Flexure Amount and Occurrence of Gaps (Table Removed) From the results of Table 1, it is understood that if the flexure is over 3 mm/m, a clearance is formed at the joint t part, while if 3 mm/m or less, no joint breakage occurs due to expansion and contraction of the joints. Therefore, the inventors studied further how to keep the flexure at the top surface of the carbon bricks down to 3 mm/m or less. There are two types of blast furnace bottoms: the type having laying beams 12 and the type setting a furnace bottom plate directly on the foundation. FIG. 2 is a view showing the mode of conveying a furnace body carrying a furnace bottom mantel on laying beams of the former case. The furnace bottom mantel and the laying beams are set on the blast furnace foundation. For this reason, it is necessary to give rigidity to the laying beams 12. The structure of the laying beams 12 is shown in FIG. 4 (a) and FIG. 4 (b) . As shown in FIG. 4 (a) and FIG. 4 (b), the laying beams 12 are comprised of H section steel assembled in rack or lattice state and filled with fire-retardant concrete 15 and has a high rigidity. The flexure amount of the laying beams configured in this way is shown in FIG. 5. If the thickness H of the laying beams is not 480 mm or more, the flexure amount found by experiments ends up exceeding 3 mm/m. It was learned that the thickness H of the laying beams has to be 480 mm or more. Further, if the thickness H of the laying beams is over 1000 mm, only the weight increases. This is not economical. In FIG. 2, the laying beams are placed on balance beams. Therefore, the balance beams 16 support the furnace bottom mantel 1 and laying beams 12 and require rigidity for keeping the flexure of the top surface of the carbon bricks in the furnace bottom mantel down to 3 mm/m or less. To keep the flexure down to 3 mm/m or less, as shown in FIG. 6 and FIG 7, the thickness A of the balance beams has to be 700 mm or more. If 700 mm or more, the flexure of the top surface of the carbon bricks can be suppressed to 3 mm/m or less, but there is a limit to the strength of the dollies for conveying the furnace bottom mantel including the balance beams and the laying beams. The height A of the balance beams therefore become 2200 mm or less. For the conveyance from the ground assembly site to the side of the blast furnace foundation, as shown in FIG. 8(b), large scale heavy weight transport carts, that is, dollies 17, are used. That is, the dollies 17 are connected in the conveyance direction (longitudinal direction) to form a plurality of dolly trains, the formed plurality of dolly trains are pulled in to the inside of the clearance formed between the balance beams 16 and the ground level in parallel, and the hydraulic pressure of the dollies is operated to raise the balance beams 16 and convey the mantel to the side of the blast furnace foundation. Note that FIG. 8(a) shows the furnace bottom mantel at which bricks have been installed at the ground assembly site, FIG. 8(b) shows the furnace bottom mantel being conveyed by the dollies, and FIG. 8(c) shows the furnace bottom mantel being conveyed using air casters. The lengths of the dolly trains arranged in parallel are reduced from the center train to the end trains as shown in FIG. 9(a). The furnace bottom mantel 1 is cylindrical in shape, so by reducing the lengths of the dolly trains from the center to the ends, it is possible to absorb the loads applied to the dollies with a good balance. Further, as the layout of the dolly trains, by making the distance between the dollies within 2.5 m, the distance P between the cylinders arranged at the dollies becomes 2.5 m or less and the distance supporting the balance beams 16 becomes 2.5 m or less. By making the support points of the balance beams 2.5 m or less, the flexure amount of the balance beams can be kept down to a minimum and parts sticking out from the outer circumference of the furnace bottom mantel can be kept to a minimum. Note that, as shown in FIG. 9(b), in the past, the general practice was to make the lengths of the dolly trains the same, but in this case, the further in distance the part from the center of the furnace bottom plate, the less the load applied from furnace bottom mantel 1 and the laying beams 12 and the balance beams 16 at its bottom surface compared with the other parts, so the furnace bottom mantel ends up greatly deforming via the balance beams. Further, the balance beams 16 are preferably shaped in accordance with the lengths of the dolly train. By shaping them in this way, it becomes possible to evenly disperse the loads applied to the dollies and in turn reduce the flexure amount at the amount of conveyance. FIG. 10(a) and FIG. 10(b) are views showing an outline of a reinforcing ring 19. The reinforcing ring 19 is arranged at the upper outer circumference of the furnace bottom mantel 1. If the part where the bricks were installed in advance in the furnace bottom mantel are the hearth bricks 9 and carbon bricks 10, since there is the shell part of the furnace bottom mantel, deformation of the furnace bottom mantel shell by the flexure of this part (collapse to the inside) is prevented. FIG. 11 (a) and FIG. 11(b) are views showing an outline of the stays 21 set at the inner surface of the furnace bottom mantel. The stays 21 are arranged radially. The stays 21 are arranged in the vicinity of the top surface of the carbon bricks installed in the furnace bottom mantel. This is because as close as possible to the top surface of the carbon bricks 10 is better so as to prevent flexure of the top surface of the carbon bricks as much as possible. As explained above, the present invention is an invention completed based on the novel and useful technical discovery never existing in the prior art that even with a furnace bottom mantel 1 increased in weight by installation of bricks in advance at a location other than the foundation of the blast furnace, if conveying the mantle while keeping the flexure amount of the top surface of the bricks installed inside the furnace down to 3 mm per meter of the mantel radius or less, it is possible to stably convey the mantel to the blast furnace foundation without causing joint breakage of the bricks or the like. Consequently, when conveying the furnace bottom mantel 1 using the dollies 17 and the air casters 18 so as to more reliably stably convey the mantel, it is preferable to convey the mantle while measuring the flexure amount of the top surface of the bricks using a predetermined measuring device. Note that an example of the layout of the air casters 18 is shown in FIG. 12. To measure the flexure amount of the top surface of the bricks, it is preferable to set a laser transmitter 26 and a plurality of laser receivers 27 receiving a laser beam 28 emitted from the laser transmitter 26 at the top surface of the bricks installed in the furnace bottom mantel 1 . Originally, when trying to measure the flexure amount of a deforming object, as shown in FIG. 17, a laser or other transmitter is set at a fixed point, an immovable reference point is set at one location of a fixed point, and the vertical direction displacements at the measurement points are found by relative comparison with the reference point. However, when trying to measure the flexure amount of the top surface of the bricks installed at the furnace bottom mantel 1, the measured object is positioned inside the part surrounded by the shell 7. It is difficult to observe the measurement points from an outside fixed point . Further, the measured object also moves several tens to several hundreds of meters, so placing the transmitter at a fixed point can be said to be impossible from the point of view of the receiving abilities of the receivers. Further, it is also possible for a person to enter the furnace to measure the flexure amount, but entering the inside of the furnace during conveyance is extremely dangerous. Further, the flexure of the top surface of the bricks changes with each instant. Manual instantaneous measurement is not possible. Consequently, as shown in FIG. 13 (a), it is preferable to set the laser transmitter 26 at any position on the top surface of the bricks installed in the furnace bottom mantel 1 and similarly set a plurality of laser receivers 27 at any positions on the top surface of the bricks. Due to this, it is possible to detect the vertical direction displacements of the laser beam received by the laser receivers 27, that is, how much the laser reception positions at the laser receivers 27 displace in the vertical direction compared with before the mantel conveyance, so as to measure the flexure amount of the top surface of the bricks. In this case, it is preferable to arrange a plurality of laser receivers 27 on a straight line. By arranging them on a straight line, as shown in FIG. 13(b), the vertical direction displacement on the straight line, that is, the flexure amount of the top surface of the bricks, can be accurately measured. The laser transmitter 26 is not particularly limited. The rotary laser shown in FIG. 13 (a) can be used. By using a rotary laser, the constantly changing vertical direction displacement can be instantaneously detected. Similarly, the laser receivers 27 are not particularly limited. Displacement measuring devices for rotary lasers can be used. Further, while not shown, it is preferable to use a wireless or wired communicating means to transmit laser reception position data in the laser receivers 27 to a worker outside the furnace. For example, by using a wireless or wired communicating means to connect the laser receivers 27 and a computer set outside the furnace, it is possible to confirm at any time the constantly changing vertical direction displacements, that is, the flexure amounts, at the laser receivers due to the mantel conveyance. Note that the vertical direction displacement can be detected by the laser receivers themselves when using laser receivers 27 able to store the laser reception positions before the mantel conveyance and able to calculate the difference with the constantly changing laser reception position. The difference can also be calculated by a computer connected by a wireless or wired communicating means. As described above, in the present invention, the laser transmitter 26 and the laser receivers 27 are set on the top surface of the bricks installed in the furnace bottom mantel, so, as shown in FIG. 14, if flexure occurs at the top surface of the bricks, a slant occurs at the laser transmitter 26. Along with this, the laser reception position at each laser receiver 27 and in turn the vertical direction displacement detected include error. The error, as shown in FIG. 14, becomes larger proportional to the distance between the laser transmitter 26 and the laser receivers 27. That is, the greater the radius of the furnace bottom mantel 1 and the greater the flexure amount, the more the liability that the measurement error cannot be ignored. FIG. 15 (a) and FIG. 15(b) are views showing another mode of the layout of the laser transmitter 26 and the laser receivers 27. By arranging them in this way, it is possible to make corrections to cancel out the error caused by the slant of the laser transmitter 26 caused by flexure of the top surface of the bricks. This method arranges a plurality of laser receivers 27 on the same straight line, uses the detected vertical direction displacements to make corrections to cancel out the error caused by the slant of the laser transmitter 26 caused by flexure of the top surface of the bricks, and make the vertical direction displacements after correction the true flexure amount. Specifically, as shown in Table 2, the endmost laser receiver A arranged on the line (measurement point A) is constantly made the reference 0. Further, the value of the laser receiver B arranged at the endmost part at the opposite side is read. The values of the receivers set between these are corrected by the set distance L. According to the above method, as shown in FIG. 16, error caused by the slant of the laser transmitter 26 caused by flexure of the top surface of the bricks can be cancelled. Due to this, the furnace bottom mantel 1 can be more stably conveyed. Table 2 (Table Removed) INDUSTRIAL APPLICABILITY As explained above, according to the present invention, the furnace bottom mantel can be stably conveyed on to the blast furnace foundation. Therefore, the present invention is high in applicability in the ferrous metal industry. We claim: 1. A method of conveyance of a furnace bottom mantle for a blast furnace constructing a blast furnace bottom mantel in advance at a location other than a blast furnace foundation, installing bricks at said furnace bottom mantel, and conveying it over the blast furnace foundation, said method of conveyance of a furnace bottom mantle characterized by conveying it while keeping the flexure amount of the top surface of the bricks installed inside the furnace to 3 mm or less per meter of the mantel radius. 2. A method of conveyance of a furnace bottom mantle for a blast furnace according to claim I characterized by installing balance beams with a thickness A of 700 mm to 2200 mm at a bottom surface of said furnace bottom mantel. 3. A method of conveyance of a furnace bottom mantle for a blast furnace according to claim 1 characterized by installing laying beams with a thickness H of 480 mm to 1000 mm at a bottom surface of said furnace bottom mantel and installing balance beams with a thickness A of 700 mm to 2200 mm at a bottom surface of said laying beams. 4. A method of conveyance of a furnace bottom mantle for a blast furnace according to claim 2 or 3 characterized by connecting dollies in 'the longitudinal direction to form a plurality of dolly trains, pulling in the dolly trains in parallel in the clearance formed between said balance beams and the ground surface, and arranging the dolly trains while reducing their lengths the further from the center line to the end lines. 5. A method of conveyance of a furnace bottom mantle for a blast furnace according to any one of claims 2 to 4 characterized by making the shapes of balance beams shapes according the lengths of the dolly trains drawn in. 6. A method of conveyance of a furnace bottom mantle for a blast furnace according to any one of claim 4 or 5 characterized by arranging the dolly trains in parallel so that the distance P between hydraulic cylinders set at said dollies becomes within 2.5 m. 7. A method of conveyance of a furnace bottom mantle for a blast furnace according to any one of claims 1 to 6 characterized by installing a laser transmitter at any position of a top surface of bricks installed at said furnace bottom mantel, similarly arranging a plurality of laser receivers in a line at any position of the top surface of the bricks, and conveying the furnace bottom mantel while measuring the flexure amount of the top surface of the bricks obtained by detecting amounts of displacement of the laser received in the vertical direction. 8. A method of conveyance of a furnace bottom mantle for a blast furnace according to claim 7 characterized by using the amount of vertical displacement detected by said laser receivers to make corrections canceling out the error generated by the slant of the laser transmitter caused by flexure of the top surface of the bricks so as to make the amounts of vertical displacement after correction the true flexure amount. 9. A method of conveyance of a furnace bottom mantle for a blast furnace, substantially as herein described with reference to the accompanying drawings.

Full Text

DESCRIPTION
METHOD OF CONVEYING FURNACE BOTTOM MANTLE FOR
BLAST FURNACE
TECHNICAL FIELD
The present invention relates to a conveyance method comprising constructing a blast furnace body in advance at a location other than the blast furnace foundation, disassembling the existing furnace body, then conveying the blast furnace on to that foundation, particularly a method of conveying a furnace bottom mantle for a blast furnace which conveys a furnace bottom mantle for a blast furnace, in which bricks have been installed in advance, to the blast furnace foundation.
BACKGROUND ART
When repairing a conventional blast furnace, the work method of dividing the aged blast furnace (old blast furnace) into small pieces and removing it from the blast furnace foundation, then welding, piece by piece, strip-like shells on the foundation to install a new blast furnace body, then stacking the bricks inside the furnace, in other words, the work method of constructing a new blast furnace from the start, has been adopted.
For this reason, with the conventional work method, a long period of time was required for repair; after the installation of the blast furnace body, high elevation work was necessary for attaching the stave cooler and cooling piping and other cooling devices, and problems occurred in regard to safety and construction quality.
On the other hand, in recent years, in order to shorten the work period, the practice has been to, in parallel with the operation of the old blast furnace, divide the new blast furnace into a plurality of ring-shaped blocks at a nearby separate location (ground assembly site), start to assemble the blocks all at once,
completely remove the old blast furnace from the foundation, then convey these blocks using dollies or other large sized heavy weight transport carts, lifting and install them by a jack, crane, or the like, and weld together the shells, piping, etc. of the parts where the blocks contact each other, that is, the so-called "block work method" has been employed (for example, see Japanese Patent Publication (B2) No. 47-1846, Japanese Patent Publication (A) No. 9-143521, and Japanese Patent Publication (A) No. 10-102778).
For example, Japanese Patent Publication (B2) No. 47-1846 discloses the technology of dividing a blast furnace into a furnace bottom, bosh, furnace belly, furnace shaft, furnace opening, and the like, successively moving them in the lateral direction and stacking the divided parts using a mobile scaffold for each part around the blast furnace, connecting the entire assembly to form an integral unit, and thereby shortening the construction period of the blast furnace.
As described above, shortening the work period in the repair of a blast furnace has been studied for a long time, but a blast furnace is a large sized structure and a heavy weight object, so actually applying this work shortening work method is difficult. Even now, manufacturers are engaged in various studies and are filing numerous patent applications.
For example, Japanese Patent Publication (A) No. 9-143521 discloses a method of repairing and constructing a blast furnace in a short period comprised of the steps of, in the disassembly or rebuilding an existing blast furnace, (a) dividing a furnace body into several ring-shaped blocks from the furnace top to the furnace bottom and constructing them at a location other than the blast furnace foundation, (b) attaching means for preventing warping or strain of the brick stacking part and means for securing circularity to the blocks other than the bottommost furnace bottom block in the ring-shaped

blocks, (c) on the other hand, stacking bricks on a furnace bottom plate set at the bottom end to construct the furnace bottom block, (d) conveying the ring-shaped blocks other than the furnace bottom block on to the blast furnace foundation by lateral conveyance, then successively lifting up and joining the blocks from the furnace top using the liftup method, and (e) conveying and installing the furnace bottom block on the foundation by lateral conveyance at the level of the blast furnace foundation level, then joining it with the top blocks.
Further, Japanese Patent Publication (A) No. 10-102778 discloses a method of construction of a blast furnace body dividing an existing furnace body of a blast furnace into a plurality of ring blocks from the furnace top to the furnace bottom and dismantling it and fabricating similar ring blocks and assembling the ring blocks on the blast furnace foundation, which method of construction of a blast furnace body comprises installing a hoist apparatus for raising or lowering a ring block of the furnace body at a location other than the blast furnace foundation, transferring the ring block to transport carts carrying a load level adjustment structure so as to match the load level with the blast furnace foundation level, transporting the block to the hoist apparatus, supporting the ring block by the hoist apparatus, then removing the load level adjustment structure, lowering the ring block to the lowest level which the transport cart can carry and transporting it to a placement site by the transport carts, on the other hand constructing the ring block at the lowest level which the transport cart can carry, transporting it to the hoist apparatus by the transport carts, supporting the ring block by the hoist apparatus, lifting it up to a level enabling movement to the blast furnace foundation level, placing it on transport carts carrying the load level adjustment structure matching the load level with the blast furnace foundation level, and conveying it over

the blast furnace foundation.
The method described in Japanese Patent Publication (B2) No. 47-1846 is a method comprising constructing each divided block on a scaffold of the same height as the assembled finished height, moving each part using the mobile scaffold after completion, and thereby completing the furnace body. By this method, since the height of the blast furnace body is about 100 meters, the furnace body is divided and assembled on the scaffold for each divided height, and the blocks are constructed on the scaffold.
Consequently, with this method, even with divided blocks, the weight reaches several thousand tons. A scaffold having a rigidity which can withstand this weight is necessary. Further, since this scaffold is necessary for each divided block, the fabrication cost of this scaffold becomes high. In the end, this method was never realized.
In the method described in Japanese Patent Publication (A) No. 9-143521, the ring-shaped blocks of a furnace body are moved over the blast furnace foundation, lifted up, and joined. Finally, the furnace bottom block is moved and the rings are placed over and joined with the furnace bottom block to complete the furnace body. At this time, the furnace bottom block is built up by stacking bricks on the furnace bottom plate.
However, the furnace bottom of a blast furnace has a diameter of as much as 10 to 20 meters. When stacking bricks on the furnace bottom plate, the deformation of the furnace bottom plate is the most important problem, but the above publication does not disclose this important problem and means for its solution. Therefore, while there was the idea of stacking bricks at a furnace bottom block, specifically how to solve the above problem is still a pending issue among the concerned parties. This method has not yet been realized in practice.
Further, Japanese Patent Publication (A) No. 10-102778 discloses installing a hoist apparatus which
raises and lowers a ring block of a furnace body at a location other than the blast furnace foundation and moving the ring block to the blast furnace foundation by transport carts carrying a load level adjustment structure so as to match the load level to the blast furnace foundation level, but does not disclose the advance installation of bricks to the blocks of the furnace body.
In this way, the block work on a blast furnace is technology essential for shortening the work period, but the more advanced the block work, the greater the weight of each block and more sophisticated the conveyance technology required. The above patent publications do not describe such conveyance technology.
DISCLOSURE OF THE INVENTION
The present invention was completed as a result of intensive studies by the present inventors to solve the above problems and has as its gist the following.
(1) A method of conveyance of a furnace bottom
mantle for a blast furnace constructing a blast furnace
bottom mantel in advance at a location other than a blast
furnace foundation, installing bricks at said furnace
bottom mantel, and conveying it over the blast furnace
foundation, said method of conveyance of a furnace bottom
mantle characterized by conveying it while keeping the
flexure amount of the top surface of the bricks installed
inside the furnace to 3 mm or less per meter of the
mantel radius.
(2) A method of conveyance of a furnace bottom
mantle for a blast furnace according to (1) characterized
by installing balance beams with a thickness A of 700 mm
to 2200 mm at a bottom surface of said furnace bottom
mantel.
(3) A method of conveyance of a furnace bottom
mantle for a blast furnace according to (1) characterized
by installing laying beams with a thickness H of 480 mm
to 1000 mm at a bottom surface of said furnace bottom mantel and installing balance beams with a thickness A of 700 mm to 2200 mm at a bottom surface of said laying beams.
(4) A method of conveyance of a furnace bottom
mantle for a blast furnace according to (2) or (3)
characterized by connecting dollies in the longitudinal
direction to form a plurality of dolly trains, pulling in
the dolly trains in parallel in the clearance formed
between said balance beams and the ground surface, and
arranging the dolly trains while reducing their lengths
the further from the center line to the end lines.
(5) A method of conveyance of a furnace bottom
mantle for a blast furnace according to any one of (2) to
(4) characterized by making the shapes of balance beams
shapes according the lengths of the dolly trains drawn
in.
(6) A method of conveyance of a furnace bottom
mantle for a blast furnace according to any one of (4) or
(5) characterized by arranging the dolly trains in
parallel so that the distance P between hydraulic
cylinders set at said dollies becomes within 2.5 m.
(7) A method of conveyance of a furnace bottom
mantle for a blast furnace according to any one of (1) to
(6) characterized by installing a laser transmitter at
any position of a top surface of bricks installed at said
furnace bottom mantel, similarly arranging a plurality of
laser receivers in a line at any position of the top
surface of the bricks, and conveying the furnace bottom
mantel while measuring the flexure amount of the top
surface of the bricks obtained by detecting amounts of
displacement of the laser received in the vertical
direction.
(8) A method of conveyance of a furnace bottom
mantle for a blast furnace according to (7) characterized
by using the amount of vertical displacement detected by
said laser receivers to make corrections canceling out
the error generated by the slant of the laser transmitter caused by flexure of the top surface of the bricks so as to make the amounts of vertical displacement after correction the true flexure amount.
According to the present invention, even a furnace bottom mantel at which bricks have been installed in advance at a location other than the foundation of the blast furnace and thereby increased in weight can be stably conveyed onto the blast furnace foundation without joint breakage etc.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view explaining an outline of a blast furnace.
FIG. 2 is a view showing an outline of the installation of a furnace bottom mantel according to the present invention.
FIG. 3 is a view explaining an outline of an experimental mini model.
FIG. 4(a) is a view schematically showing a planar structure of laying beams.
FIG. 4(b) is a view showing the cross-sectional structure of laying beams.
FIG. 5 is a view showing the relationship between the thickness of the laying beams and the flexure amount.
FIG. 6 is a view schematically showing the cross-sectional structure of balance beams.
FIG. 7 is a view showing the relationship between the thickness of balance beams and the flexure amount.
FIG. 8(a) is a view showing a furnace bottom mantel in which bricks are installed at a ground assembly site.
FIG. 8(b) is a view showing a furnace bottom mantel conveyed by dollies.
FIG. 8(c) is a view showing a furnace bottom mantel conveyed using air casters.
FIG. 9(a) is a view showing a layout of dollies according to the present invention.
FIG. 9(b) is a view showing a conventional layout.
FIG. 10(a) is a view showing an example of a mode of installation of a reinforcing ring.
FIG. 10(b) is a view showing the reinforcing ring expanded.
FIG. 11(a) is a view showing an example of a mode of installation of stays.
FIG. 11(b) is a view showing the stays expanded.
FIG. 12 is a view showing an example of a layout of air casters.
FIG. 13(a) is a view showing an example of a layout of a laser transmitter and laser receivers.
FIG. 13(b) is a view showing the flexure amount of the top surface of the bricks.
FIG, 14 is a view showing the error caused by slant of a laser transmitter caused by flexure of top surface of the bricks.
FIG. 15 (a) is a view showing another example of a layout of a laser transmitter and laser receivers.
FIG. 15(b) is a view showing another example of a layout of a laser transmitter and laser receivers.
FIG. 16 is a view showing a method of correction canceling out error generated due to slant of the laser transmitter caused by flexure of the top surface of the bricks.
FIG. 17 is a view explaining the technological significance of setting a measuring device on the top surface of bricks installed in a furnace bottom mantel.
BEST MODE FOR CARRYING OUT THE INVENTION Below, referring to FIG. 1 to FIG. 17, the best mode for carrying out the present invention will be explained.
As seen in FIG. 1, a blast furnace is disassembled and repaired by cutting a furnace body 2 of the blast furnace in the horizontal direction to separate it into a plurality of sections in the vertical direction and removing them from the blast furnace foundation 5 to

outside the blast furnace foundation. On the other hand, the furnace body 2 to be newly installed is constructed by a number of blocks set in advance at a location than the blast furnace foundation (ground assembly site) .
FIG. 2 is a view showing the state when conveying the furnace bottom mantel 1 divided into blocks and constructed at the ground assembly site. At the ground assembly site where the furnace body is constructed in advance, balance beams 16 are set at the ground surface. On the top surfaces of the balance beams 16, laying beams 12 are placed. Between the laying beams 12 and the balance beams 16 are installed air casters 18 for making the laying beams float up. The furnace bottom mantel 1 is constructed on the top surfaces of the laying beams 12 configured in this way.
Note that FIG. 4 and FIG. 12 show one example of the layout of the air casters 18, but the method of arrangement of the air casters 18 is not limited to this.
Explained in detail, the shell 7 is placed standing on the furnace bottom plate 6, the stave cooler 8 is laid on the inside of the shell 7, and the hearth bricks 9 are installed via the joint filling material 11 on the top surface of the furnace bottom plate 6. Then, carbon bricks 10 are installed on the top surface of the hearth bricks 9 via a joint filling material. In this state, the weight of the furnace bottom mantel 1 becomes approximately 1000 tons or more. To construct this furnace bottom mantel 1 on the balance beams 16 set at the ground assembly site, it is necessary to give rigidity to the balance beams 16 to prevent deformation of the furnace bottom mantel.
However, there was never any technology disclosing specifically what to do to prevent deformation of the furnace bottom mantel. Therefore, the present inventors engaged in repeated numerical analyses and experiments by the finite element method and as a result obtained the discovery that if conveying the furnace bottom mantel 1

while keeping the flexure amount per meter of the mantel radius down to 3 mm at the top surface of the carbon bricks 10 installed on the furnace bottom mantel 1, it is possible to place it on the blast furnace foundation and use it as it is.
In experiments, as shown in FIG. 3, a mini model obtained by installing hearth bricks 9 on a furnace bottom plate 6 via a stamp material 25 and installing carbon bricks 10 on the top surface of the hearth bricks 9 via a stamp material 25 was employed.
As shown in FIG. 3, jacks 24 were placed at the bottom of the furnace bottom mantel of the mini model, the jacks were operated, and the state of gaps with the joints and stamp material 25 installed between the carbon bricks was observed. The results are shown in Table 1.
Table I. Relationship of Flexure Amount and Occurrence of Gaps

(Table Removed)

From the results of Table 1, it is understood that if the flexure is over 3 mm/m, a clearance is formed at the joint t part, while if 3 mm/m or less, no joint breakage occurs due to expansion and contraction of the joints. Therefore, the inventors studied further how to keep the flexure at the top surface of the carbon bricks down to 3 mm/m or less.
There are two types of blast furnace bottoms: the type having laying beams 12 and the type setting a furnace bottom plate directly on the foundation. FIG. 2 is a view showing the mode of conveying a furnace body carrying a furnace bottom mantel on laying beams of the former case. The furnace bottom mantel and the laying beams are set on the blast furnace foundation. For this reason, it is necessary to give rigidity to the laying beams 12.

The structure of the laying beams 12 is shown in FIG. 4 (a) and FIG. 4 (b) . As shown in FIG. 4 (a) and FIG. 4 (b), the laying beams 12 are comprised of H section steel assembled in rack or lattice state and filled with fire-retardant concrete 15 and has a high rigidity. The flexure amount of the laying beams configured in this way is shown in FIG. 5.
If the thickness H of the laying beams is not 480 mm or more, the flexure amount found by experiments ends up exceeding 3 mm/m. It was learned that the thickness H of the laying beams has to be 480 mm or more. Further, if the thickness H of the laying beams is over 1000 mm, only the weight increases. This is not economical.
In FIG. 2, the laying beams are placed on balance beams. Therefore, the balance beams 16 support the furnace bottom mantel 1 and laying beams 12 and require rigidity for keeping the flexure of the top surface of the carbon bricks in the furnace bottom mantel down to 3 mm/m or less.
To keep the flexure down to 3 mm/m or less, as shown in FIG. 6 and FIG 7, the thickness A of the balance beams has to be 700 mm or more. If 700 mm or more, the flexure of the top surface of the carbon bricks can be suppressed to 3 mm/m or less, but there is a limit to the strength of the dollies for conveying the furnace bottom mantel including the balance beams and the laying beams. The height A of the balance beams therefore become 2200 mm or less.
For the conveyance from the ground assembly site to the side of the blast furnace foundation, as shown in FIG. 8(b), large scale heavy weight transport carts, that is, dollies 17, are used. That is, the dollies 17 are connected in the conveyance direction (longitudinal direction) to form a plurality of dolly trains, the formed plurality of dolly trains are pulled in to the inside of the clearance formed between the balance beams 16 and the ground level in parallel, and the hydraulic
pressure of the dollies is operated to raise the balance beams 16 and convey the mantel to the side of the blast furnace foundation.
Note that FIG. 8(a) shows the furnace bottom mantel at which bricks have been installed at the ground assembly site, FIG. 8(b) shows the furnace bottom mantel being conveyed by the dollies, and FIG. 8(c) shows the furnace bottom mantel being conveyed using air casters.
The lengths of the dolly trains arranged in parallel are reduced from the center train to the end trains as shown in FIG. 9(a). The furnace bottom mantel 1 is cylindrical in shape, so by reducing the lengths of the dolly trains from the center to the ends, it is possible to absorb the loads applied to the dollies with a good balance.
Further, as the layout of the dolly trains, by making the distance between the dollies within 2.5 m, the distance P between the cylinders arranged at the dollies becomes 2.5 m or less and the distance supporting the balance beams 16 becomes 2.5 m or less. By making the support points of the balance beams 2.5 m or less, the flexure amount of the balance beams can be kept down to a minimum and parts sticking out from the outer circumference of the furnace bottom mantel can be kept to a minimum.
Note that, as shown in FIG. 9(b), in the past, the general practice was to make the lengths of the dolly trains the same, but in this case, the further in distance the part from the center of the furnace bottom plate, the less the load applied from furnace bottom mantel 1 and the laying beams 12 and the balance beams 16 at its bottom surface compared with the other parts, so the furnace bottom mantel ends up greatly deforming via the balance beams.
Further, the balance beams 16 are preferably shaped in accordance with the lengths of the dolly train. By shaping them in this way, it becomes possible to evenly
disperse the loads applied to the dollies and in turn reduce the flexure amount at the amount of conveyance.
FIG. 10(a) and FIG. 10(b) are views showing an outline of a reinforcing ring 19. The reinforcing ring 19 is arranged at the upper outer circumference of the furnace bottom mantel 1. If the part where the bricks were installed in advance in the furnace bottom mantel are the hearth bricks 9 and carbon bricks 10, since there is the shell part of the furnace bottom mantel, deformation of the furnace bottom mantel shell by the flexure of this part (collapse to the inside) is prevented.
FIG. 11 (a) and FIG. 11(b) are views showing an outline of the stays 21 set at the inner surface of the furnace bottom mantel. The stays 21 are arranged radially. The stays 21 are arranged in the vicinity of the top surface of the carbon bricks installed in the furnace bottom mantel. This is because as close as possible to the top surface of the carbon bricks 10 is better so as to prevent flexure of the top surface of the carbon bricks as much as possible.
As explained above, the present invention is an invention completed based on the novel and useful technical discovery never existing in the prior art that even with a furnace bottom mantel 1 increased in weight by installation of bricks in advance at a location other than the foundation of the blast furnace, if conveying the mantle while keeping the flexure amount of the top surface of the bricks installed inside the furnace down to 3 mm per meter of the mantel radius or less, it is possible to stably convey the mantel to the blast furnace foundation without causing joint breakage of the bricks or the like.
Consequently, when conveying the furnace bottom mantel 1 using the dollies 17 and the air casters 18 so as to more reliably stably convey the mantel, it is preferable to convey the mantle while measuring the

flexure amount of the top surface of the bricks using a predetermined measuring device.
Note that an example of the layout of the air casters 18 is shown in FIG. 12.
To measure the flexure amount of the top surface of the bricks, it is preferable to set a laser transmitter 26 and a plurality of laser receivers 27 receiving a laser beam 28 emitted from the laser transmitter 26 at the top surface of the bricks installed in the furnace bottom mantel 1 .
Originally, when trying to measure the flexure amount of a deforming object, as shown in FIG. 17, a laser or other transmitter is set at a fixed point, an immovable reference point is set at one location of a fixed point, and the vertical direction displacements at the measurement points are found by relative comparison with the reference point.
However, when trying to measure the flexure amount of the top surface of the bricks installed at the furnace bottom mantel 1, the measured object is positioned inside the part surrounded by the shell 7. It is difficult to observe the measurement points from an outside fixed point .
Further, the measured object also moves several tens to several hundreds of meters, so placing the transmitter at a fixed point can be said to be impossible from the point of view of the receiving abilities of the receivers. Further, it is also possible for a person to enter the furnace to measure the flexure amount, but entering the inside of the furnace during conveyance is extremely dangerous. Further, the flexure of the top surface of the bricks changes with each instant. Manual instantaneous measurement is not possible.
Consequently, as shown in FIG. 13 (a), it is preferable to set the laser transmitter 26 at any position on the top surface of the bricks installed in the furnace bottom mantel 1 and similarly set a plurality

of laser receivers 27 at any positions on the top surface of the bricks.
Due to this, it is possible to detect the vertical direction displacements of the laser beam received by the laser receivers 27, that is, how much the laser reception positions at the laser receivers 27 displace in the vertical direction compared with before the mantel conveyance, so as to measure the flexure amount of the top surface of the bricks.
In this case, it is preferable to arrange a plurality of laser receivers 27 on a straight line. By arranging them on a straight line, as shown in FIG. 13(b), the vertical direction displacement on the straight line, that is, the flexure amount of the top surface of the bricks, can be accurately measured.
The laser transmitter 26 is not particularly limited. The rotary laser shown in FIG. 13 (a) can be used. By using a rotary laser, the constantly changing vertical direction displacement can be instantaneously detected. Similarly, the laser receivers 27 are not particularly limited. Displacement measuring devices for rotary lasers can be used.
Further, while not shown, it is preferable to use a wireless or wired communicating means to transmit laser reception position data in the laser receivers 27 to a worker outside the furnace. For example, by using a wireless or wired communicating means to connect the laser receivers 27 and a computer set outside the furnace, it is possible to confirm at any time the constantly changing vertical direction displacements, that is, the flexure amounts, at the laser receivers due to the mantel conveyance.
Note that the vertical direction displacement can be detected by the laser receivers themselves when using laser receivers 27 able to store the laser reception positions before the mantel conveyance and able to calculate the difference with the constantly changing
laser reception position. The difference can also be calculated by a computer connected by a wireless or wired communicating means.
As described above, in the present invention, the laser transmitter 26 and the laser receivers 27 are set on the top surface of the bricks installed in the furnace bottom mantel, so, as shown in FIG. 14, if flexure occurs at the top surface of the bricks, a slant occurs at the laser transmitter 26. Along with this, the laser reception position at each laser receiver 27 and in turn the vertical direction displacement detected include error.
The error, as shown in FIG. 14, becomes larger proportional to the distance between the laser transmitter 26 and the laser receivers 27.
That is, the greater the radius of the furnace bottom mantel 1 and the greater the flexure amount, the more the liability that the measurement error cannot be ignored.
FIG. 15 (a) and FIG. 15(b) are views showing another mode of the layout of the laser transmitter 26 and the laser receivers 27. By arranging them in this way, it is possible to make corrections to cancel out the error caused by the slant of the laser transmitter 26 caused by flexure of the top surface of the bricks.
This method arranges a plurality of laser receivers 27 on the same straight line, uses the detected vertical direction displacements to make corrections to cancel out the error caused by the slant of the laser transmitter 26 caused by flexure of the top surface of the bricks, and make the vertical direction displacements after correction the true flexure amount.
Specifically, as shown in Table 2, the endmost laser receiver A arranged on the line (measurement point A) is constantly made the reference 0. Further, the value of the laser receiver B arranged at the endmost part at the opposite side is read. The values of the receivers set
between these are corrected by the set distance L.
According to the above method, as shown in FIG. 16, error caused by the slant of the laser transmitter 26 caused by flexure of the top surface of the bricks can be cancelled. Due to this, the furnace bottom mantel 1 can be more stably conveyed.

Table 2

(Table Removed)

INDUSTRIAL APPLICABILITY
As explained above, according to the present invention, the furnace bottom mantel can be stably conveyed on to the blast furnace foundation. Therefore, the present invention is high in applicability in the ferrous metal industry.

We claim:
1. A method of conveyance of a furnace bottom
mantle for a blast furnace constructing a blast furnace
bottom mantel in advance at a location other than a blast
furnace foundation, installing bricks at said furnace
bottom mantel, and conveying it over the blast furnace
foundation, said method of conveyance of a furnace bottom
mantle characterized by conveying it while keeping the
flexure amount of the top surface of the bricks installed
inside the furnace to 3 mm or less per meter of the
mantel radius.
2. A method of conveyance of a furnace bottom
mantle for a blast furnace according to claim I
characterized by installing balance beams with a
thickness A of 700 mm to 2200 mm at a bottom surface of
said furnace bottom mantel.
3. A method of conveyance of a furnace bottom
mantle for a blast furnace according to claim 1
characterized by installing laying beams with a thickness
H of 480 mm to 1000 mm at a bottom surface of said
furnace bottom mantel and installing balance beams with a
thickness A of 700 mm to 2200 mm at a bottom surface of
said laying beams.
4. A method of conveyance of a furnace bottom
mantle for a blast furnace according to claim 2 or 3
characterized by connecting dollies in 'the longitudinal
direction to form a plurality of dolly trains, pulling in
the dolly trains in parallel in the clearance formed
between said balance beams and the ground surface, and
arranging the dolly trains while reducing their lengths
the further from the center line to the end lines.
5. A method of conveyance of a furnace bottom
mantle for a blast furnace according to any one of claims
2 to 4 characterized by making the shapes of balance
beams shapes according the lengths of the dolly trains
drawn in.
6. A method of conveyance of a furnace bottom

mantle for a blast furnace according to any one of claim 4 or 5 characterized by arranging the dolly trains in parallel so that the distance P between hydraulic cylinders set at said dollies becomes within 2.5 m.
7. A method of conveyance of a furnace bottom
mantle for a blast furnace according to any one of claims
1 to 6 characterized by installing a laser transmitter at
any position of a top surface of bricks installed at said
furnace bottom mantel, similarly arranging a plurality of
laser receivers in a line at any position of the top
surface of the bricks, and conveying the furnace bottom
mantel while measuring the flexure amount of the top
surface of the bricks obtained by detecting amounts of
displacement of the laser received in the vertical
direction.
8. A method of conveyance of a furnace bottom
mantle for a blast furnace according to claim 7
characterized by using the amount of vertical
displacement detected by said laser receivers to make
corrections canceling out the error generated by the
slant of the laser transmitter caused by flexure of the
top surface of the bricks so as to make the amounts of
vertical displacement after correction the true flexure
amount.
9. A method of conveyance of a furnace bottom mantle for a blast furnace, substantially as herein described with reference to the accompanying drawings.

Documents:

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Patent Number

278335

Indian Patent Application Number

7475/DELNP/2007

PG Journal Number

53/2016

Publication Date

23-Dec-2016

Grant Date

20-Dec-2016

Date of Filing

27-Sep-2007

Name of Patentee

NIPPON STEEL ENGINEERING CO.,LTD

Applicant Address

6-3, OTEMACHI 2-CHOME, CHIYODA-KU, TOKYO 100-8071, JAPAN.

Inventors:

#	Inventor's Name	Inventor's Address
1	KAZUMI KURAYOSHI	C/O NIPPON STEEL ENGINEERING CO.,LTD.,46-59, OAZA-NAKABARU, TOBATA-KU, KITAKYUSHU-SHI, FUKUOKA 804-8505, JAPAN.
2	HIROSHI TAKASAKI	C/O NIPPON STEEL ENGINEERING CO.,LTD.,46-59, OAZA-NAKABARU, TOBATA-KU, KITAKYUSHU-SHI, FUKUOKA 804-8505, JAPAN

PCT International Classification Number

C21B 7/00

PCT International Application Number

PCT/JP2006/306984

PCT International Filing date

2006-03-27

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	2005-363618	2005-12-16	Japan
2	2005-094898	2005-03-29	Japan