JP2008180433A - Heat-treating furnace for tabular member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat-treating furnace for a tabular member capable of heat-treating a tabular member with good heat efficiency without using a setter, and conveying it into the furnace without deformation or flawing. <P>SOLUTION: The heat-treating furnace is a furnace carrying out heat treatment of the tabular member P while conveying it in a furnace longitudinal direction. A floor face of a furnace chamber 2 is composed of heat resistant glass or ceramics provided with a vent hole 5, and it has a lifting and holding function of the tabular member P. The vent hole 5 is bored into a heat resistant glass plate 4 or a ceramics plate 3, or it can be an intergranular space of porous ceramic. Or the vent hole 5 can be formed on a flat face of a ceramic pipe. A flat face is maintained, suiting lifting conveyance even in high temperature conditions. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a heat treatment furnace used for drying or firing a flat member represented by a large flat panel such as a plasma display panel or a liquid crystal display panel.

  A flat panel is a flat member manufactured by printing a functional material in multiple layers on a substrate made of glass or ceramics, and applying a heat treatment such as drying or baking. In order to efficiently perform the heat treatment of such a flat member, a roller hearth kiln as disclosed in Patent Document 1 has been widely used.

  A roller hearth kiln is a tunnel furnace in which a large number of rollers are arranged at a constant pitch in the furnace, and each roller is rotated in the same direction by a driving means provided outside the furnace, thereby transporting the workpiece placed thereon. is there. The inside of the furnace is divided into a pre-tropical zone, a dry zone, a firing zone, a cooling zone, and the like, and a predetermined temperature gradient is formed in the furnace chamber by heating means such as a burner and a heater. A plate-like member as a workpiece is heat-treated while passing through a pre-tropical zone, a drying zone, a firing zone, a cooling zone, or the like while being transferred in the furnace length direction by a number of rollers.

  Recently, however, flat panel substrates have become thinner and larger. In order to produce a wide flat plate member, it is necessary to enlarge the furnace width and lengthen the roller. However, if the length of one roller exceeds 3 m, the dimensional accuracy decreases, and the width exceeds that. There is a problem that it is difficult to cope with a large flat plate-like member.

  Even if the roller itself constitutes a horizontal plane, when the flat plate member passes through the high temperature region supported by rollers arranged at a constant pitch, the portion between the rollers hangs down due to gravity, and the flat plate member undulates slightly. There was a deformation. In addition, the contact surface of the substrate with the roller may be wrinkled. Such a tendency becomes particularly remarkable when the flat plate member is a glass substrate. Such a problem can be avoided by placing a flat plate member on a setter and transporting the inside of the furnace. However, not only the flat plate member but also the setter is heated and cooled, so that extra energy is required. As a result, another problem arises that the thermal efficiency of the above becomes worse.

Furthermore, since the flat plate member is mainly heated by radiant heat in the furnace chamber, the upper surface without an obstacle is easily heated, but the lower surface on which the roller is provided is not easily heated, and the temperature distribution on the front and back sides is not uniform. Therefore, there is a possibility that the flat plate member is deformed so as to warp on the roller.
JP 2005-156016 A

  Accordingly, an object of the present invention is to carry out heat treatment with high thermal efficiency by transporting the inside of a furnace without deforming or brazing the flat plate member without using a setter even when the flat plate member is thin and large. It is providing the heat processing furnace of the flat member which can do.

  The flat plate member heat treatment furnace of the present invention made to solve the above problems is a flat plate member heat treatment furnace that performs heat treatment while conveying the flat plate member in the furnace length direction, and is a floor surface of the furnace chamber. Is made of heat-resistant glass or ceramics provided with air holes, and has a function of holding the floating plate member.

  In the present invention, the air hole may be a hole formed in heat-resistant glass or ceramics, or may be a gap between particles of a porous ceramic. The vents may be provided on the entire floor surface, but may be formed at intervals in the furnace length direction. In this case, the air holes can be formed on the flat surface of the ceramic pipe.

  In the heat treatment furnace of the present invention, the floor surface of the furnace chamber is provided with the function of maintaining the floating of the flat plate member, so that the flat plate member can be transported in the furnace without being deformed or brazed without using a setter. Can be heat-treated. In the heat treatment furnace of the present invention, since the floor surface of the furnace chamber is made of heat-resistant glass or ceramics provided with vent holes, unlike metal plates and resin plates, expansion and deformation hardly occur even under high temperature conditions. For this reason, there is an advantage that a flat surface suitable for conveyance can be maintained even in a high temperature zone, and the leakage of the floating gas is less likely to occur.

  In particular, if the vent holes are formed at intervals in the furnace length direction as in claim 4, the processing of heat-resistant glass and ceramics constituting the floor surface is reduced, and the supply pipe for the floating gas can be reduced. . Further, if the floor surface is formed by directly forming the vent holes on the flat surface of the ceramic pipe as in the sixth aspect, the seal portion is eliminated, so that the problem of leakage of the floating gas can be avoided.

Preferred embodiments of the present invention are shown below.
FIG. 1 is a sectional view in the furnace length direction showing an embodiment of the present invention, and FIG. 2 is a plan view. In these drawings, reference numeral 1 denotes a furnace body for performing a heat treatment such as firing while transporting the flat plate member P in the furnace length direction, and 2 denotes the furnace chamber. The floor surface of the furnace chamber 2 is composed of a ceramic plate 3 and a heat-resistant glass plate 4.

  The ceramic plate 3 is formed with air holes 5 at regular intervals as shown in the figure, and a floating gas such as compressed air and nitrogen gas supplied from a chamber 6 provided below the ceramic plate 3 is blown out. Can be kept floating on the floor. Further, the heat-resistant glass plates 4 are alternately arranged with the ceramic plates 3 and are merely members for forming a flat surface without the air holes 5. As a result, the vent holes 5 are formed at intervals in the furnace length direction. The heat-resistant glass plate 4 includes a height adjusting mechanism 7 and is adjusted so that there is no step between the heat-resistant glass plate 4 and the ceramic plate 3.

  The material of both the ceramic plate 3 and the heat-resistant glass plate 4 is not particularly limited as long as it has heat resistance capable of withstanding the furnace temperature. Since these materials have a very low coefficient of thermal expansion compared to metal, there is little distortion even in a high temperature range, and a flat floor surface suitable for floating transportation can be maintained. The diameter of the vent holes 5 is 1 to 5 mm, the pitch is 10 to 200 mm, and the pressure of the levitation gas is about 0.05 kPa to 1 MPa. These values depend on the size and weight of the flat plate member P to be floated and held. May be determined as appropriate.

  In this embodiment, the air holes 5 are formed in the ceramic plate 3, but the air holes can also be formed in the heat-resistant glass plate 4. Further, in this embodiment, the air holes 5 are formed in the ceramic plate 3 by drilling, but porous ceramics can be used as the ceramic plate 3 and the inter-particle gaps can be used as the air holes. Such a porous ceramic can be obtained by a known method in which ceramic particles having a relatively large particle size are mixed with an inorganic binder, formed into a flat plate shape, and fired.

  In order to give the floor surface the function of maintaining the floating of the flat plate member P, the air holes 5 may be arranged uniformly over the entire floor surface. As shown in this embodiment, the heat-resistant glass plates 4 without the vent holes 5 are alternately arranged with the ceramic plates 3 provided with the vent holes 5, and the vent holes 5 are formed at intervals in the furnace length direction. There is no problem. This is because the gas blown out from the air holes 5 forms a thin layer while diffusing between the floor surface and the flat plate member P, and exhibits a floating holding function. The partial formation of the zone in which the vent holes 5 are formed in this way is advantageous in reducing the cost of the furnace.

  The arrangement method of the zone in which the vent holes 5 are formed includes a staggered pattern or a stripe pattern. In the case of the stripe pattern, there are a furnace length direction and a furnace width direction. In the present invention, any of these arrangement methods may be adopted. However, the staggered arrangement tends to increase the cost because the piping structure of the levitation gas is complicated. Further, in the arrangement of the stripes in the furnace length direction, the levitation gas having the same temperature is supplied from the same chamber 6 in the furnace length direction, which is the length direction of the stripes. In the place where the temperature curve is set inside, there is a possibility that a temperature difference occurs between the portion of the flat plate member P that is in contact with the levitation gas and the portion that is not in contact. Therefore, as in this embodiment, the vent holes 5 are most preferably striped in the furnace width direction.

  In the present invention, since such a floating holding method is adopted, the friction coefficient between the flat plate member P and the floor surface becomes almost zero. Moreover, since the floor surface is constituted by the heat-resistant glass plate 4 or the ceramic plate 3, unlike a metal plate or a resin plate, the flat surface can be maintained with little expansion or deformation even under high temperature conditions. In this way, heat treatment can be performed while transporting in the furnace without deforming or brazing the flat plate member P without using a setter.

  In addition, the flat plate member P cannot be advanced in the furnace simply by providing the floor surface with a floating holding function. For this reason, it is necessary to provide an appropriate conveying mechanism in the furnace to apply a forward force to the flat plate member P. However, since the force required for this is very small, for example, as shown in FIG. 2, a large number of conveying rollers 8 are arranged on the side of the floor surface and rotated around the vertical axis. The flat plate member P can be moved forward by the frictional force therebetween. The conveyance rollers 8 may be arranged on both sides, but the floor surface is slightly inclined about 1 to 10 ° in the furnace width direction, and the conveyance rollers 8 are arranged only on the lower side where the flat plate member P slides under its own weight. That's fine.

  In the above-described embodiment, the air holes 5 are formed in the ceramic plate 3, but in this case, a seal for preventing leakage of the floating gas is required at the joint portion with the chamber 6. The second embodiment shown in FIGS. 3 and 4 eliminates the need for this seal, and is formed by drilling the vent holes 5 on the flat surface of the ceramic pipe 9 having a square cross section at predetermined intervals. The portions between the ceramic pipes 9 are connected by the heat-resistant glass plate 4 or the ceramic plate 3 to constitute a flat floor surface.

  In this case, since the ceramic pipe 9 itself functions as the chamber 6, the chamber 6 as in the first embodiment can be omitted, and of course the seal between the ceramic plate 3 and the chamber 6 described above. Is also unnecessary. As shown in FIG. 4, the levitation gas may be supplied from one end of the ceramic pipe 9. According to this embodiment, there is no risk of seal leakage even in a high temperature portion, and there is an advantage that the supply pipe for the floating gas can be simplified.

  In any embodiment, temperature-controlled hot air can be used as the levitation gas. In this case, the temperature of the hot air can be set individually in the furnace length direction, and the levitation gas itself can be used as a heating source for the flat plate member P. Since the levitation gas is directly blown onto the flat plate member P, excellent heating efficiency can be achieved. However, it goes without saying that auxiliary heating means such as a heater may be arranged in the furnace chamber 2.

It is sectional drawing of the furnace length direction which shows the 1st Embodiment of this invention. It is a top view of FIG. It is sectional drawing of the furnace length direction which shows the 2nd Embodiment of this invention. It is a perspective view of a ceramic pipe.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Furnace 2 Furnace room 3 Ceramic plate 4 Heat-resistant glass plate 5 Vent 6 Chamber 7 Height adjustment mechanism 8 Roller 9 Ceramic pipe

Claims (5)

  A flat plate heat treatment furnace that performs heat treatment while conveying the flat member in the furnace length direction, and the floor surface of the furnace chamber is made of heat-resistant glass or ceramics provided with vent holes, and the floating retention function of the flat plate member A heat treatment furnace for flat plate members characterized by having   2. The heat treatment furnace for a flat plate member according to claim 1, wherein the vent hole is formed by drilling a heat resistant glass or ceramic.   2. The flat plate member heat treatment furnace according to claim 1, wherein the air holes are inter-granular gaps of porous ceramic.   2. The flat plate member heat treatment furnace according to claim 1, wherein the vent holes are formed at intervals in the furnace length direction.   2. The flat plate-shaped heat treatment furnace according to claim 1, wherein the vent hole is formed on a flat surface of the ceramic pipe.

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