Heating furnace pedestal, assembly pedestal and heating furnace

Abstract

To provide a heating furnace pedestal and an assembly pedestal which have excellent heat resistance, load resistance and thermal shock resistance, and a heating furnace which comprises at least one of the heating furnace pedestal and the assembly pedestal.SOLUTION: A heating furnace pedestal is made of an alumina-based inorganic fiber aggregate in the form of plural laminated plates. The heating furnace pedestal is the fired one, and is arranged so that the lamination direction of the alumina-based inorganic fiber aggregate is vertical in a heating furnace, and a material to be heated is placed on an upper face. An assembly pedestal is obtained by parallelling the plural heating furnace pedestals. Regarding the heating furnace, at least one of the heating furnace pedestal and the assembly pedestal is arranged at the inside of the furnace.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a heating furnace pedestal, an assembled pedestal, and a heating furnace.

Background Art

[0002] In a heating furnace for heating a metal workpiece such as steel, a pedestal for placing the workpiece is installed.

[0003] Conventionally, for the pedestal of a heating furnace, castable refractories or the like have been used (Patent Document 1).

[0004] Note that an inorganic fiber molded body is used as a heat insulating material for the inner wall of an industrial furnace, burner tiles, etc. (Patent Document 2).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] A pedestal made of refractory bricks or castable refractories is inferior in thermal shock resistance and may be damaged when heating and cooling are repeated.

[0007] The inorganic fiber molded body described in Patent Document 2 is inferior in load-bearing property and may be damaged when a heavy object such as a metal workpiece is placed on it.

[0008] An example of the object of the present invention is to provide a heating furnace pedestal and an assembled pedestal that are excellent in heat resistance, load-bearing property, and thermal shock resistance, and a heating furnace in which at least one of the heating furnace pedestal and the assembled pedestal is disposed in the furnace. Other objects of the present invention will become apparent from the description herein.

Means for Solving the Problem

[0009] The heating furnace pedestal according to one aspect of the present invention is a heating furnace pedestal composed of a plurality of laminated plate-shaped alumina-based inorganic fiber aggregates, which is fired, and is arranged in the heating furnace such that the lamination direction of the alumina-based inorganic fiber aggregates is in the vertical direction, and a material to be heated is placed on the upper surface.

[0010] The heating furnace pedestal according to one aspect of the present invention is solidified by a fired product of an inorganic binder.

[0011] The heating furnace pedestal according to one aspect of the present invention has a shape extending in one direction and has holes extending at least partially in the one direction.

[0012] The heating furnace pedestal according to one aspect of the present invention has a bulk density of 0.21 to 0.45 g / cm 3 3.

[0013] The heating furnace pedestal according to one aspect of the present invention has a flexural strength in the lamination direction of 0.1 N / mm 2 2 or more.

[0014] The heating furnace pedestal according to one aspect of the present invention has a displacement amount of 6 mm or more when a maximum load is applied in the lamination direction.

[0015] The combined pedestal according to one aspect of the present invention is a structure in which a plurality of heating furnace pedestals of such an aspect are arranged in parallel.

[0016] The combined pedestal according to one aspect of the present invention has a connecting body in which the heating furnace pedestals are connected by a connecting member.

[0017] In the combined pedestal according to one aspect of the present invention, the connecting member has a bar extending in the parallel direction of the heating furnace pedestals and a branched portion extending from the bar and inserted into the heating furnace pedestal.

[0018] In the combined pedestal according to one aspect of the present invention, the connecting bodies are stacked in multiple stages vertically.

[0019] In the heating furnace according to one aspect of the present invention, at least one of the heating furnace pedestal and the combined pedestal of such an aspect is arranged inside the furnace.

Advantages of the Invention

[0020] According to the above aspect of the present invention, it is possible to provide a heating furnace pedestal and a combined pedestal that are excellent in heat resistance, load resistance, and thermal shock resistance, and a heating furnace in which at least one of the heating furnace pedestal and the combined pedestal is arranged inside the furnace.

Brief Description of the Drawings

[0021]

Figure 1

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Figure 10

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Figure 12

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Figure 16

Mode for Carrying Out the Invention

[0022] Hereinafter, embodiments will be described with reference to the drawings.

[0023] [Configuration of Heating Furnace Pedestals 1 and 1A] FIG. 1 is a perspective view showing an example of a heating furnace pedestal 1 according to an embodiment. This heating furnace pedestal 1 has a rectangular parallelepiped shape that is long in one direction and has a hole 1a that extends at least partially in the one direction. However, the heating furnace pedestal 1 may have a shape other than a rectangular parallelepiped. In the present embodiment, an example in which the hole 1a penetrates in the one direction will be described.

[0024] This heating furnace pedestal 1 has a plurality of laminated alumina-based inorganic fiber aggregates (hereinafter, sometimes referred to as "inorganic fiber aggregates") 2. Each inorganic fiber aggregate 2 preferably extends continuously from one end face 1x side to the other end face 1y side of the heating furnace pedestal 1. Thereby, the bending strength of the heating furnace pedestal 1 can be improved as compared with the case where the heating furnace pedestal 1 is not continuous in the longitudinal direction.

[0025] The heating furnace pedestal 1A shown in FIG. 2 is formed by laminating inorganic fiber aggregates 2A and 2B that are not continuous from one end face 1x side to the other end face 1y side in the longitudinal direction of the heating furnace pedestal 1A. The symbol 2i indicates the joint of the inorganic fiber aggregates 2A and 2B. In this case, it is preferable to shift the joints 2i of the adjacent inorganic fiber aggregates 2A and 2B in the longitudinal direction without overlapping them in the vertical direction. Thereby, the bending strength of the heating furnace pedestal 1 can be made comparable to the bending strength of the heating furnace pedestal 1 shown in FIG.

[0026] This heating furnace pedestal 1, 1A is solidified by the fired product of the inorganic binder produced in the firing process of the compression body described later.

[0027] In this embodiment, the hole 1a has a square cross-sectional shape in the direction orthogonal to the one direction, but is not limited thereto. Also, the position of the hole 1a is at the center on the end face of the heating furnace pedestal 1, 1A, but is not limited thereto.

[0028] In this embodiment, one hole 1a is provided in the heating furnace pedestal 1, 1A. However, when the size of the heating furnace pedestal 1, 1A is large, two or more holes may be provided. When the size of the heating furnace pedestal 1, 1A is small, the hole 1a may not be provided. In this embodiment, the case where the hole 1a is provided in the heating furnace pedestal 1, 1A will be described. However, the heating furnace pedestal 1, 1A may not have the hole 1a regardless of its size.

[0029] In this embodiment, the inorganic fibers constituting the inorganic fiber aggregate 2, 2A, 2B are made of crystalline alumina-silica fibers or the like. Preferred examples of the inorganic fibers are as described later.

[0030] The bulk density of the heating furnace pedestal 1, 1A of this embodiment is 0.21 g / cm 3 or more, and also 0.45 g / cm 3 or less, particularly 0.40 g / cm 3 or less, and particularly preferably 0.35 g / cm 3 or less.

[0031] This heating furnace pedestal 1, 1A is arranged in the heating furnace so that the surface in the direction orthogonal to the stacking direction (the plate surface 2f of the inorganic fiber aggregate 2, 2A, 2B) is substantially horizontal, and is used such that the material to be heated is loaded thereon. FIG. 16 is a cross-sectional view showing an example of a state where the material to be heated 81 is loaded on the heating furnace pedestal 1 in the heating furnace 80. The heating furnace pedestal 1, 1A may support the material to be heated 81 by only one, or may support the material to be heated 81 by a plurality.

[0032] The bending strength of this heating furnace pedestal 1, 1A in the loading direction (stacking direction) is 0.1 N / mm2 Above, especially 0.15 N / mm 2 Above, for example 0.20 N / mm 2 It is preferably the above. The method for measuring the bending strength is as described in the examples below.

[0033] Also, the displacement amount when the maximum load is applied in the loading direction (lamination direction) of the heating furnace pedestals 1 and 1A is preferably 6 mm or more. In other words, when the maximum load is applied in the loading direction of the heating furnace pedestals 1 and 1A, the heating furnace pedestals 1 and 1A are bent by at least 6 mm or more and do not break in this state. When the displacement amount when the maximum load is applied is 6 mm or more, it can be evaluated that the heating furnace pedestals 1 and 1A have characteristics of being sufficiently bent against the load and being difficult to break. The heating furnace pedestals 1 and 1A can support heavy objects such as the heated material 81 in the bent state. The maximum load means the maximum load when a bending strength test is performed under the conditions shown in the examples described below.

[0034] [Manufacturing method of heating furnace pedestal 1] The manufacturing method of this heating furnace pedestal 1 will be described below with reference to FIGS. 3 to 9. FIGS. 3 to 9 show the forming process of the compression package 8.

[0035] In this manufacturing method, first, using the boat-shaped main mold 3 shown in FIGS. 3 and 6(a), the square tube-shaped medium mold 4 shown in FIG. 4, and the flat plate-shaped plate mold 5 shown in FIG. 5, a compressed body of the inorganic fiber aggregates 7 and 7A is formed. Note that FIG. 6(a) is a cross-sectional view taken along line VIa-VIa of FIG. 3.

[0036] The main mold 3, the medium mold 4, and the plate mold 5 are all made of punching plates (plates having a large number of holes 3a, 4a, and 5a). The holes 3a to 5a are preferably substantially circular holes with a diameter of 2 to 20 mm, particularly about 2 to 5 mm, but the shape and size of the holes are not limited to this. For clarity of the drawing, the reference numerals 3a to 5a are attached only to some of the holes.

[0037] Both end faces 3T of the main mold 3 are provided with medium-sized insertion ports 3K for inserting the end portions 4T of the medium-sized mold 4. The main mold 3 is preferably an assembled type in which the punching plate on at least one side surface 3S is detachably attached to the punching plate on the bottom surface 3R by bolts or the like. With this assembled main mold 3, when demolding as described later, the main mold 3 can be disassembled and the molded product can be easily demolded.

[0038] The length L4 in the longitudinal direction of the medium-sized mold 4 is the same as or longer than the length L3 in the longitudinal direction of the main mold 3.

[0039] The width W4 in the direction orthogonal to the longitudinal direction of the medium-sized mold 4 is preferably 10 to 40%, particularly about 10 to 35% of the width W3 of the main mold 3. Also, the height H4 of the medium-sized mold 4 is preferably 10 to 60%, particularly about 10 to 40% of the height H3 of the main mold 3.

[0040] To manufacture the heating furnace pedestal 1, first, as shown in Fig. 6(b), a required number of sheet-like inorganic fiber aggregates 7 are laid in the main mold 3. The configuration of the inorganic fiber aggregate 7 will be described later. The inorganic fiber aggregate 7 has a strip shape having substantially the same length as the total length in the longitudinal direction of the heating furnace pedestal 1 and substantially the same width as the width of the heating furnace pedestal 1.

[0041] After stacking a required number of inorganic fiber aggregates 7 to form a laminate 60, it is pressed from above with a pressing plate (not shown) and compressed in the thickness direction to form a compressed laminate 70 of the inorganic fiber aggregates 7 (Fig. 7).

[0042] Then, as shown in Fig. 7, the medium-sized mold 4 is placed on the central portion in the width direction of the compressed laminate 70 of the inorganic fiber aggregates 7. Both end portions 4T of the medium-sized mold 4 are inserted into the medium-sized insertion ports 3K of the main mold 3. At this time, it is preferable that one end portion 4T of the medium-sized mold 4 is flush with the end face 3T of the main mold 3.

[0043] Next, as shown in FIG. 8, an inorganic fiber aggregate 7A is disposed between the side surface 4S of the medium-sized mold 4 and the side surface 3S of the main mold 3. The inorganic fiber aggregate 7A is made of the same material as the inorganic fiber aggregate 7 and has a width substantially equal to the distance d between the side surface 4S of the medium-sized mold 4 and the side surface 3S of the main mold 3.

[0044] After stacking the required number of inorganic fiber aggregates 7A until it is higher than the upper surface 4J of the medium-sized mold 4, it is pressed from above with a pressing plate (not shown), and the upper surface 71J of the laminate 71 of the compressed and shrunk inorganic fiber aggregates 7A is flush or substantially flush with the upper surface 4J of the medium-sized mold 4 (FIG. 8).

[0045] Next, the required number of inorganic fiber aggregates 7 are stacked on the laminate 71 of the compressed and shrunk inorganic fiber aggregates 7A and on the upper side of the medium-sized mold 4. In this case, the stacking height of the inorganic fiber aggregates 7 is set to be higher than the upper end surface 3t of the main mold 3.

[0046] Thereafter, as shown in FIG. 9, the plate-shaped mold 5 is placed on the upper surface 72J of the laminate 72, and the laminate 72 is pressed from above downward so that the upper surface of the laminate 72 of the inorganic fiber aggregates 7 is flush or substantially flush with the upper end surface 3t of the main mold 3. Next, the plate-shaped mold 5 is fixed to the main mold 3 with bolts, screws, etc. to obtain the compression package 8 in FIG. 9. Thus, the formation process of the compression package 8 is completed.

[0047] When forming the compression package 8, it is preferable to compress the laminates 70, 71, and 72 of the inorganic fiber aggregates 7 and 7A so that the thicknesses thereof are 41 to 94%, particularly about 45 to 70%, of the thickness before compression.

[0048] In the above formation process of the compression package 8, a release sheet may be provided on the inner surface of the main mold 3, the outer surface of the medium-sized mold 4, and the lower surface of the plate-shaped mold 5. As the release sheet, a synthetic resin fiber cloth such as a fluororesin or a glass cloth can be used.

[0049] After the formation process of the compression package 8 is completed, the compression package 8 is immersed in a binder liquid containing an inorganic sol, a metal salt, or the like. The binder liquid penetrates into each inorganic fiber aggregate 7, 7A through the holes 3a, 4a, 5a. The preferred composition of the binder liquid is as described below.

[0050] After the binder liquid has sufficiently penetrated into the inorganic fiber aggregates 7, 7A, the compression package 8 is pulled out of the binder liquid and drained. This draining may be performed only by gravity, but it is preferable to perform suction draining.

[0051] To perform suction draining, the posture of the compression package 8 is set with its longitudinal direction as the vertical direction (the posture with one end 4T of the medium 4 on the upper side). The end 4T on the upper end side of the medium 4 of the compression package 8 is closed with a non-porous plate (not shown). Also, a suction hose (not shown) is connected to the end 4T on the lower end side of the medium 4. Then, the inside of the medium 4 is suctioned through the suction hose.

[0052] As a result, air flows in through the holes 3a, 5a of the main mold 3 and the plate mold 5, and a considerable portion of the binder liquid stored in each inorganic fiber aggregate 7, 7A passes through the hole 4a and enters the medium 4, then flows downward and is discharged. As a result, a predetermined amount of the binder liquid adheres and remains on the laminate, so the suction is stopped, the mold is removed, and a compressed body of the inorganic fiber aggregates 7, 7A to which the binder liquid is adhered is obtained. After drying this compressed body, it is fired to obtain the heating furnace pedestal 1 shown in FIG. 1. The preferred conditions for drying and firing are as described below.

[0053] Note that, if necessary, post-processing may be performed on the heating furnace pedestal after firing. For example, burrs are cut off with an NT cutter or the like, and the outer surface of the heating furnace pedestal is shaped to the standard dimensions.

[0054] [Function and Effect] The heating furnace pedestals 1 and 1A of the present embodiment are formed by laminating a plurality of inorganic fiber aggregates 7 and 7A, compressing them in the lamination direction, impregnating them with a binder liquid, and drying and firing them to harden. These heating furnace pedestals 1 and 1A are excellent in heat resistance and thermal shock resistance, have a high bulk density, high flexural strength, and can support a heated material 81 with a large weight in the heating furnace 80. These heating furnace pedestals 1 and 1A do not break even at high temperatures and do not crack even when the temperature rise and fall are repeated, and can stably support the heated material 81 over a long period of time.

[0055] In these heating furnace pedestals 1 and 1A, the overlapping inorganic fiber aggregates 2 or the inorganic fiber aggregates 2A and 2B are bonded by a binder fired product, so they are integrated as a whole.

[0056] These heating furnace pedestals 1 and 1A have holes 1a, and by inserting the branched portions 11b of the connecting member 11 described later into the holes 1a, they can be made into a connected body of a plurality of heating furnace pedestals 1 and 1A.

[0057] These heating furnace pedestals 1 and 1A do not crack even due to a sudden change in the furnace temperature or a temperature change at the moment when the heated material is loaded. Also, since they do not crack, the heated material does not fall from the heating furnace pedestals 1 and 1A.

[0058] These heating furnace pedestals 1 and 1A are lighter than castable refractories and are easy to carry into and install in the heating furnace 80.

[0059] [Usage example of heating furnace pedestal] Only one of the heating furnace pedestals 1 or 1A may be arranged in the heating furnace. A plurality of heating furnace pedestals 1 or 1A may be arranged at a plurality of locations in the heating furnace while being separated from each other, or a plurality of heating furnace pedestals 1 or 1A may be arranged adjacent to each other at one or a plurality of locations. Also, a plurality of heating furnace pedestals 1 or 1A may be arranged one above the other. The heating furnace pedestals 1 and 1A may be used in combination.

[0060] [Combined pedestal] The combined pedestal 10 is formed by arranging a plurality of heating furnace pedestals 1 or 1A in parallel. The combined pedestal 10 may be a connecting body 12 in which a plurality of heating furnace pedestals 1 or 1A arranged in parallel in advance are connected by a connecting member 11, or may be in a state where they are not connected by the connecting member 11. Further, the combined pedestal 10 may be formed by arranging a plurality of such connecting bodies or non-connected ones by the connecting member 11 in parallel, or by stacking them in multiple upper and lower stages, or a combination thereof. An example is shown in FIGS. 10 and 11.

[0061] In FIG. 10, a connecting body 12 formed by arranging three heating furnace pedestals 1 in parallel and connecting them with a connecting member 11 is stacked in three upper and lower stages to form the combined pedestal 10.

[0062] The connecting member 11 is made of a heat-resistant material such as stainless steel or ceramics. As shown in FIG. 11, it has a rod-shaped bar 11a and a plurality of branched portions 11b extending from the bar 11a in a direction orthogonal to the longitudinal direction of the bar 11a. The branched portions 11b are spaced apart in the longitudinal direction of the bar 11a and extend in the same direction from the bar 11a. The tip side of the extending direction of the branched portion 11b has a tapered shape, which is easy to insert into the hole 1a. The interval between the branched portions 11b, 11b is the same as the interval between the holes 1a of the parallel heating furnace pedestals 1.

[0063] By inserting the branched portion 11b into the hole 1a of each heating furnace pedestal 1, adjacent heating furnace pedestals 1 are connected. The manner in which the branched portion 11b is inserted into the hole 1a may be either clearance fitting or press fitting.

[0064] The bar 11a can be used as a handle when carrying the connecting body of the heating furnace pedestal 1.

[0065] This combined pedestal 10 is also lighter than the castable refractory, and it is easy to carry into the heating furnace 80 and adjust the position within the heating furnace 80.

[0066] Since this combined pedestal 10 connects the heating furnace pedestals 1 with the connecting member 11, displacement of each heating furnace pedestal 1 is prevented.

[0067] Since the combined pedestal 10 uses the heating furnace pedestal 1 with standard dimensions, the manufacturing cost is also low.

[0068] In Fig. 10, three heating furnace pedestals 1 are connected in parallel, but the number of heating furnace pedestals 1 can be arbitrarily adjusted according to the application. For example, two or four or more heating furnace pedestals 1 may be connected in parallel. Also, in Fig. 10, the connected bodies of the heating furnace pedestals 1 are stacked in three stages, but it may be in one stage, two stages, or four or more stages.

[0069] In Fig. 10, the heating furnace pedestals 1 are combined, but the heating furnace pedestals 1A may be combined, or the heating furnace pedestals 1 and 1A may be combined.

[0070] [Preferred forms of the inorganic fiber aggregates 7, 7A] In this embodiment, the inorganic fiber aggregates 7, 7A preferably comprise needle inorganic fiber aggregates such as needle blankets subjected to needling treatment. Note that needle marks (pinholes) are formed in the needle inorganic fiber aggregates by the needling treatment.

[0071] Preferred as the alumina-based inorganic fibers constituting the inorganic fiber aggregate are, in terms of heat resistance, fiber strength (toughness), and safety, alumina fibers, particularly alumina / silica fibers, especially polycrystalline alumina / silica fibers. The alumina weight fraction of the alumina fibers is preferably 65 wt% or more and 98 wt% or less, more preferably 70 wt% or more and 95 wt% or less, and even more preferably 70 wt% or more and 74 wt% or less.

[0072] The composition ratio (weight ratio) of alumina / silica of the alumina / silica fibers is preferably in the range called the mullite composition or high alumina composition of 65 - 98 / 35 - 2, more preferably in the range of 70 - 95 / 30 - 5, and particularly preferably in the range of 70 - 74 / 30 - 26.

[0073] It is preferable that 80% by weight or more, preferably 90% by weight or more, and particularly preferably all of the alumina-based inorganic fibers constituting the inorganic fiber aggregate are the polycrystalline alumina / silica-based fibers having the above mullite composition.

[0074] The average fiber diameter of the inorganic fibers is preferably 5 to 7 μm. If the average fiber diameter of the inorganic fibers is too thick, the repulsive force and toughness of the fiber aggregate will be lost. If it is too thin, the amount of dust floating in the air may increase, and the probability of containing fibers with a fiber diameter of 3 μm or less will be high.

[0075] [Method for manufacturing inorganic fiber aggregate] The method for manufacturing the inorganic fiber aggregate is not particularly limited. Usually, it is manufactured through a step of obtaining an aggregate of inorganic fiber precursors, a step of subjecting the obtained aggregate of inorganic fiber precursors to needling treatment, and a firing step of firing the needled aggregate of inorganic fiber precursors to obtain an inorganic fiber aggregate.

[0076] Hereinafter, such a method for manufacturing an inorganic fiber aggregate will be described by exemplifying a method for manufacturing an alumina / silica-based fiber aggregate. However, the inorganic fiber aggregate according to the present invention is not limited to the alumina / silica-based fiber aggregate at all.

[0077] [Spinning process] In order to manufacture an aggregate of alumina / silica-based fibers by the precursor fiberization method, first, a spinning solution containing basic aluminum chloride, a silicon compound, an organic polymer as a thickener, and water is spun by the blowing method to obtain an aggregate of alumina / silica fiber precursors.

[0078] [Preparation of spinning solution] Basic aluminum chloride; Al(OH) 3-x Cl xIt can be prepared, for example, by dissolving metallic aluminum in an aqueous solution of hydrochloric acid or aluminum chloride. The value of x in the above chemical formula is usually 0.45 to 0.54, preferably 0.5 to 0.53. As the silicon compound, silica sol is preferably used, but other water-soluble silicon compounds such as tetraethyl silicate and water-soluble siloxane derivatives can also be used. As the organic polymer, for example, water-soluble polymer compounds such as polyvinyl alcohol, polyethylene glycol, and polyacrylamide are preferably used. The degree of polymerization of these is usually 1000 to 3000.

[0079] The spinning solution has a ratio of aluminum derived from basic aluminum chloride to silicon derived from the silicon compound, in terms of the mass ratio of Al 2 O 3 to SiO 2 usually in the range of 99:1 to 65:35, preferably 99:1 to 70:30, an aluminum concentration of 170 to 210 g / L, and an organic polymer concentration of 20 to 50 g / L is preferred.

[0080] When the amount of the silicon compound in the spinning solution is less than the above range, the alumina constituting the short fibers is liable to be α-aluminized, and moreover, embrittlement of the short fibers due to coarsening of the alumina particles is likely to occur. On the other hand, when the amount of the silicon compound in the spinning solution is more than the above range, the amount of silica (SiO 2 O 3 ·2SiO 2 ) generated together with mullite (3Al 2 ) increases and the heat resistance is liable to decrease.

[0081] When the concentration of aluminum in the spinning solution is less than 170 g / L or the concentration of the organic polymer is less than 20 g / L, in either case, an appropriate viscosity of the spinning solution cannot be obtained, and the fiber diameter of the resulting alumina / silica-based fibers becomes small. That is, as a result of too much free water in the spinning solution, the drying rate during spinning by the blowing method is slow, the stretching proceeds excessively, the fiber diameter of the spun precursor fibers changes, and short fibers with a predetermined average fiber diameter and a sharp fiber diameter distribution cannot be obtained.

[0082] On the one hand, when the concentration of aluminum exceeds 210 g / L or the concentration of the organic polymer exceeds 50 g / L, in either case, the viscosity is too high to form a spinning solution. The preferred concentration of aluminum in the spinning solution is 180 - 200 g / L, and the preferred concentration of the organic polymer is 30 - 40 g / L.

[0083] The above spinning solution is prepared by adding a silicon compound and an organic polymer in an amount such that the ratio of Al 2 O 3 :SiO 2 is obtained, and concentrating so that the concentrations of aluminum and the organic polymer are within the above ranges.

[0084] [Spinning] Spinning (fiberization of the spinning solution) is usually carried out by the blowing method of supplying the spinning solution into a high-speed spinning air flow, whereby an alumina / silica-based fiber precursor is obtained. The structure of the spinning nozzle used in the above spinning is not particularly limited. For example, as described in Japanese Patent No. 2602460, the air flow blown out from the air nozzle and the spinning solution flow extruded from the spinning solution supply nozzle are parallel flows, and moreover, a structure in which the parallel flow of air is sufficiently rectified and contacts the spinning solution is preferable.

[0085] Also, during spinning, first, under conditions where evaporation of moisture and decomposition of the spinning solution are suppressed, fibers sufficiently drawn from the spinning solution are formed, and then it is preferable that these fibers are quickly dried. For this purpose, it is preferable to change the atmosphere from a state where evaporation of moisture is suppressed to a state where evaporation of moisture is promoted in the process from when the fibers are formed from the spinning solution until they reach the fiber collector.

[0086] An aggregate of alumina / silica fiber precursors can be recovered as a continuous sheet (thin layer sheet) by an aggregating device having a structure in which an endless belt made of wire mesh is installed so as to be substantially perpendicular to the spinning air flow, and while rotating the endless belt, a spinning air flow containing the alumina / silica fiber precursors is made to collide with the endless belt. By stacking these thin layer sheets, an aggregate of alumina / silica fiber precursors can be obtained.

[0087] [Needling treatment step] The aggregate of alumina / silica fiber precursors obtained by spinning is then subjected to needling treatment. Usually, the needling treatment is performed by a needle punching machine. Needle punching is a method in which an aggregate of alumina / silica fiber precursors (fibers) is repeatedly pierced with needles (pins) that move up and down at high speed, and the fibers are entangled by protrusions called barbs engraved on the needles.

[0088] The needle mark density is 2 to 200 punches / cm 2 , particularly 2 to 150 punches / cm 2 , especially 2 to 100 punches / cm 2 , among which 2 to 50 punches / cm 2 is preferable.

[0089] [Firing step of aggregate of alumina / silica fiber precursors] The firing of the aggregate of alumina / silica fiber precursors after the needling treatment is usually carried out at a temperature of 900 °C or higher, preferably 1000 to 1500 °C. When the firing temperature is less than 900 °C, only fragile alumina / silica fibers with low strength can be obtained due to insufficient crystallization. When the firing temperature exceeds 1500 °C, only fragile alumina / silica fibers with low strength can be obtained due to the progress of crystal grain growth of the fibers. Therefore, this firing temperature is more preferably 1000 to 1400 °C, and even more preferably 1100 to 1400 °C. Also, the firing time depends on the thickness of the inorganic fiber precursor aggregate, etc., but is usually 0.1 to 10 hours, preferably 0.2 to 8 hours, more preferably 0.3 to 6 hours, and particularly preferably 0.5 to 4 hours.

[0090] The bulk density of the inorganic fiber aggregate obtained by this firing is 0.05 to 0.2 g / cm 3 , particularly preferably 0.08 to 0.18 g / cm 3 . Also, the thickness of the inorganic fiber aggregate is not particularly limited, but is preferably about 2 to 35 mm, particularly preferably about 4 to 15 mm.

[0091] [Binder liquid to be impregnated into the compression package 8] There are no particular restrictions on the inorganic binder that constitutes the binder liquid to be impregnated into the compression package 8, and any inorganic sol, metal salt, or mixture thereof that forms an oxide after firing may be used. Specific examples will be described below, but the present invention is not limited thereto.

[0092] Examples of the inorganic sol include alumina sol, zirconia sol, titania sol, magnesia sol, and calcia sol. Examples of the metal salt include organic acid salts such as formate, acetate, citrate, oxalate, benzoate, and malate of aluminum, zirconium, titanium, or magnesium, and mineral acid salts such as nitrate. Among them, alumina sol is preferable in that its coefficient of thermal expansion is close to that of the inorganic fiber aggregate. A plurality of inorganic sols may be used as the inorganic binder.

[0093] The concentration of the inorganic binder liquid is preferably 5 to 15% by weight as a solid content, particularly preferably 7 to 12% by weight. Also, it is preferable to adjust the viscosity of the binder liquid to 5 to 150 cp.

[0094] The adhesion rate of the inorganic binder is preferably 10 to 50% by weight, particularly preferably about 20 to 35% by weight.

[0095] Here, the adhesion rate of the inorganic binder refers to the ratio, expressed as a percentage, of the weight of the inorganic binder solid content after drying and before firing to the weight of the inorganic fiber, as shown in the following formula.

[0096] (Adhesion rate) = (Weight of inorganic binder solid content) / (Weight of inorganic fiber aggregate) × 100

[0097] As a method for measuring the adhesion rate of an inorganic binder to inorganic fibers, a firing method can be mentioned. Specifically, it is preferable to measure by the method described in a known document (International Publication No. 2013 / 035645) (a method based on weight loss by firing at 1000 ° C for 3 hours).

[0098] By setting the binder adhesion amount and bulk density high in this way, the strength and rigidity of the heating furnace pedestal will be high.

[0099] [Drying conditions after draining the binder liquid] There are no particular restrictions on the drying conditions after draining the binder liquid. Specifically, methods such as contacting hot air at 40 to 200 ° C, particularly 60 to 150 ° C, or allowing it to stand for about 2 to 15 hours in an atmosphere of 100 ° C to 200 ° C can be mentioned. The suction dehydration step and the drying step may be performed simultaneously, and in this way, the working efficiency is improved.

[0100] [Firing conditions of the compact] By firing the compact, volatile components (such as organic components) contained in the solid content of the binder liquid are removed, and the inorganic substance or metal salt is fired (including calcination) to form a metal oxide or a fired product mainly composed of it. The inorganic fibers are bound to each other by this fired product (fired body), and the heating furnace pedestal is hardened, and the required strength and rigidity are imparted to the heating furnace pedestal. In the present invention, it is preferable to fire at 600 to 1200 ° C, particularly 1000 to 1200 ° C for 2 to 6 hours, particularly 2 to 4 hours, in an oxygen-containing atmosphere such as air so that the organic components completely disappear and the inorganic binder such as alumina sol is corundumized.

Example

[0101] A heating furnace pedestal was manufactured using the main mold 3 having the shape shown in FIGS. 3 and 6(a) and the plate mold 5 having the shape shown in FIG. 5. Since the medium mold 4 is not used, the manufactured heating furnace pedestal has a rectangular parallelepiped shape without the hole 1a. The inner dimensions of the main mold 3 and the diameters of the holes 3a and 5a are as follows.

[0102] Length in the longitudinal direction: 640 mm Width: 150 mm Depth: 150 mm Diameter of holes 3a and 5a: 3 mm

[0103] [Manufacturing procedure] Needle inorganic fiber aggregate of alumina / silica-based fiber with a thickness of 10 mm, a bulk density of 0.165 g / cm 3 , and a needle mark density of 3 punches / cm 2 The needle blanket (MAFTEC (registered trademark) manufactured by Maftec Co., Ltd., average fiber diameter 5.5 μm, alumina content approximately 72% by weight, silica content approximately 28% by weight), which is a needle inorganic fiber aggregate of alumina / silica-based fiber, was cut into a width of 150 mm and a length of 660 mm.

[0104] A glass cloth with a thickness of 0.5 mm (Tyuco Flow (registered trademark) G-type fabric manufactured by Chukyo Kasei Co., Ltd.) was attached to the master mold 3 as a release sheet. Then, 23 sheets of the above needle blanket (total thickness 230 mm) were laminated in the master mold 3, and then compressed to a thickness of 150 mm with the plate mold 5. Next, the plate mold 5 was bolted to the master mold 3 and fixed to form a compressed package in the same state as in Fig. 9 (however, the medium mold 4 was not present).

[0105] This compressed package was immersed in an alumina sol with a solid content concentration of 9.6% by weight (alumina sol 200 manufactured by Nissan Chemical Industries, Ltd.) for 15 hours and then lifted, and de-liquefied by suction at a negative pressure of -11.3 to -13.0 kPa for 40 minutes. Then, the compressed package was surrounded by a box-shaped body, and while suction was continued, warm air at 100 to 140 °C was introduced into the box-shaped body for 4 hours to dry it. After drying, it was demolded. When the binder adhesion rate of this dried compressed body was measured by the method described in International Publication No. 2013 / 035645, it was 24% by weight.

[0106] Next, it was fired at 1000 °C for 3 hours in an air atmosphere. After cutting off the burrs after firing with a cutter, the outer shape was shaped to 150 × 150 × 640 mm with a band saw. Then, test pieces with a thickness of 50 mm and a thickness of 25 mm were prepared as the rectangular parallelepiped-shaped heating furnace pedestal 1' shown in Fig. 12.

[0107] Also, as shown in Fig. 12, the bending strength of this heating furnace pedestal 1' (test pieces with thicknesses of 50 mm and 25 mm) was measured. In Fig. 12, a load P was applied in the direction of arrow P perpendicular to the lamination plane (the lamination direction, i.e., the loading direction) at a load application acceleration of 1 mm / min. The distance between the support jigs A1 and A2 was set to 100 mm, and the length D of the contact surfaces between the support jigs A1 and A2 and the indenter A3 and the heating furnace pedestal 1' was set to 150 mm.

[0108] In Fig. 13, for the heating furnace pedestal 1' (test piece with a thickness of 50 mm), a load P was applied in the same direction as the lamination plane (the direction of arrow P in Fig. 13) at a load application acceleration of 1 mm / min. The distance between the support jigs B1 and B2 was set to 100 mm, and the length D of the contact surfaces between the support jigs B1 and B2 and the indenter B3 and the heating furnace pedestal 1' was set to 150 mm.

[0109] As a result, the bending strength in the case of a thickness of 50 mm in Fig. 12 was 0.262 N / mm 2 and the bending strength in the case of Fig. 13 was 0.004 N / mm 2 The load-displacement curve during the bending strength measurement test is shown in Fig. 15. As shown in Fig. 15, in the lamination direction for the test piece with a thickness of 25 mm, the displacement amount when a maximum load of 0.08 kN was applied was 6 mm. Also, in the lamination direction for the test piece with a thickness of 50 mm, the displacement amount when a maximum load of 0.22 kN was applied was 22 mm. The deformed state of the heating furnace pedestal 1' during the bending strength measurement is shown in Fig. 14.

[0110] From the above embodiments, it was confirmed that this heating furnace pedestal 1' has a sufficiently high bending strength in the lamination direction, and even when a large-weight workpiece to be heated is placed on the heating furnace pedestal 1', the heating furnace pedestal 1' is sufficiently bent and does not break.

[0111] The embodiments and examples of the present invention have been described above with reference to the drawings, but these are examples of the present invention, and various configurations other than the above can also be adopted.

Description of Reference Numerals

[0112] 1, 1A, 1' Heating furnace pedestal 1a Hole 2, 2A, 2B alumina-based inorganic fiber aggregate 3 main mold 3a hole 4 medium mold 4a hole 5 plate mold 5a hole 7, 7A inorganic fiber aggregate 10 combined pedestal 11 connecting member 11a bar 11b branched part 12 connecting body 60 laminate of inorganic fiber aggregate 7 before compression 70 laminate of compressed inorganic fiber aggregate 7 71 laminate of compressed inorganic fiber aggregate 7A 80 heating furnace 81 material to be heated

Claims

1. A heating furnace pedestal comprising a plurality of laminated plate-shaped alumina-based inorganic fiber aggregates, wherein the heating furnace pedestal is fired, and in the heating furnace, it is arranged such that the lamination direction of the alumina-based inorganic fiber aggregate is in the vertical direction, and a material to be heated is placed on the upper surface.

2. The heating furnace pedestal according to claim 1, wherein the heating furnace pedestal is solidified by a fired product of an inorganic binder.

3. The heating furnace pedestal according to claim 1, having a shape extending in one direction and having holes extending at least partially in the one direction.

4. The bulk density is 0.21 to 0.45 g / cm ３ The heating furnace pedestal according to claim 1, which is such that

5. The bending strength in the stacking direction is 0.1 N / mm ２ or more, the heating furnace pedestal according to claim 1.

6. The heating furnace pedestal according to claim 1, wherein the displacement amount when the maximum load is applied in the lamination direction is 6 mm or more.

7. An assembled pedestal in which a plurality of the heating furnace pedestals according to claim 1 are arranged in parallel.

8. The assembled pedestal according to claim 7, having a connected body in which the heating furnace pedestals are connected by a connecting member.

9. The assembled pedestal according to claim 8, wherein the connecting member has a bar extending in the parallel direction of the heating furnace pedestals and a branched portion extending from the bar and inserted into the heating furnace pedestals.

10. The assembled pedestal according to claim 8, wherein the connected bodies are stacked in multiple upper and lower stages.

11. A heating furnace in which at least one of the heating furnace pedestal according to any one of claims 1 to 6 and the assembled pedestal according to any one of claims 7 to 10 is arranged in the furnace.

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