JP2008164234A - Heat treatment furnace for flat plate-shaped member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat treatment furnace for a flat plate-shaped member, which efficiently performs heat treatment of the flat plate-shaped member without deforming and damaging the same. <P>SOLUTION: A floating gas jetting means 4 is disposed on a floor surface of a furnace chamber 2 to float and retain the flat plate-shaped member P, and the flat plate-shaped member is conveyed in the furnace longitudinal direction. A temperature of a floating gas is changed in the furnace longitudinal direction to apply prescribed temperature history to the flat plate-shaped member P floated and retained by the floating gas. The jetting means 4 is composed of a chamber 3 having pores on its top face. The temperature distribution can be also controlled even in the furnace width direction if the chamber 3 divided into the furnace width direction is used. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a heat treatment furnace for a flat member used for manufacturing 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 has been widely used as shown in Patent Document 1.

  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. The plate-like member, which is a workpiece, is heat-treated by being given a predetermined temperature history while passing through the pre-tropical zone, the drying zone, the firing zone, and the cooling zone while being transferred in the furnace length direction by a number of rollers.

  Recently, however, flat panel substrates have become thinner and larger, and glass substrates are often employed. For this reason, when it supported by the roller arrange | positioned by fixed pitch and passes a high temperature area | region, the part between rollers drooped by gravity, and the flat member may deform | transform so that it may wave slightly. In addition, the contact surface of the substrate with the roller may be wrinkled. Such a problem can be avoided by placing a flat plate member on the setter and transporting the inside of the furnace. However, the setter is also heated and cooled, so that extra energy is required, resulting in poor thermal efficiency. This will cause problems.

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. There is a possibility that the substrate is deformed to warp on the roller. This non-uniform temperature distribution may also occur in the furnace width direction, and the temperature difference between the center portion and both side portions of the furnace chamber tends to promote warpage of the flat plate member.
JP 2005-156016 A

  Accordingly, an object of the present invention is to provide a plate-like member that can be heat-treated with high efficiency without using a setter, without deforming or brazing the plate-like member, even when the substrate is thin and large. It is to provide a heat treatment furnace.

  The present invention made to solve the above-mentioned problems is a heat treatment furnace for a flat plate member that performs heat treatment while transferring the flat plate member in the furnace length direction, and jets of levitation gas to the floor of the furnace chamber A means is provided to float and hold the flat plate member, and the temperature of the levitation gas is changed in the furnace length direction to give a predetermined temperature history to the flat plate member that is floated and held by the levitation gas. Is.

  In addition, in this invention, it is preferable to set it as the structure which provided the transfer means of the flat member levitation | floating held by the gas for levitation | floating at the side of the furnace chamber. The levitation gas jetting means preferably includes a chamber divided in the furnace length direction, and each chamber is preferably connected to a supply source of heated gas having different temperatures. It is more preferable if each of the chambers is provided with a chamber that is also divided in the furnace width direction, and each chamber is connected to a supply source of heated gas having different temperatures.

  The heat treatment furnace of the present invention employs a system in which a floating member is provided on the floor surface of the furnace chamber to float and hold the flat member, so that the flat member can be deformed without using a setter. It can be heat-treated while being transported in the furnace without being attached. In addition, the heat treatment furnace of the present invention employs a system in which the temperature of the levitation gas is changed in the furnace length direction and a predetermined temperature history is given to the plate-like member that is levitated and held by the levitation gas. It is directly heated by the levitation gas from the lower surface, and can be heat-treated with high thermal efficiency. Since the levitation gas ejected from the lower surface of the flat plate member fills the furnace chamber, the flat plate member can be heated evenly from both the front and back surfaces without installing another heating means in the furnace chamber. Warpage due to non-uniform distribution can also be prevented.

Preferred embodiments of the present invention are shown below.
FIG. 1 is a conceptual sectional view in the furnace length direction showing an embodiment of the present invention, and FIG. 2 is a conceptual sectional view in the furnace width direction. In these figures, 1 is a furnace body, 2 is a furnace chamber, and 3 is a chamber constituting the floor of the furnace chamber. A large number of pores are formed on the upper surface of each chamber 3 to form a floating gas jetting means 4, and a floating gas such as air or nitrogen supplied into the chamber 3 is jetted upward. Thus, the flat plate member P can be floated and held.

  The pore diameter may be 1 to 5 mm, the pitch is 1 to 20 mm, and the pressure of the levitation gas may be about 0.05 kPa to 1 MPa, and the pores are not necessarily provided uniformly on the entire surface. In this embodiment, the flat plate member P is formed in the shape of a square glass substrate, and the size thereof is about 1 to 3 mm in thickness and about 2 to 3 m on one side.

  Since such a floating holding method is adopted, the flat plate member P moves in the furnace so as to slide without contacting the lower surface with other objects. Can be eliminated at all. Moreover, since it is not necessary to use a setter for preventing wrinkles and deformation as in the prior art, the amount of heat taken out by the setter is eliminated, and the thermal efficiency of the furnace is improved.

  As shown in FIG. 1, the chamber 3 constituting the buoyant gas jetting means is divided into a large number in the furnace length direction. Each chamber 3 is connected to a supply source of heated gas having different temperatures. In this embodiment, a heater 7 is provided on a pipeline 6 that supplies pressurized air from the blower 5 to each chamber 3, and the pressurized air supplied to each chamber 3 is individually heated. A temperature sensor 8 is attached to the outlet side of the heater 7 to detect the temperature of the pressurized air supplied to each chamber 3.

  The type of the heater 7 is not particularly limited, and may be a structure in which the air passage is heated by a burner from the outside in addition to various electric heaters. However, since the heated air is in direct contact with the flat plate member P, a structure in which the burner frame and the pressurized air are in direct contact with each other is not preferable because foreign matter may adhere to the flat plate member P. Moreover, it is good also as a system which collect | recovers the exhaust heat from a furnace chamber with a heat exchanger instead of the heater 7, and heats the levitation gas.

  The temperature of the heated air supplied to each chamber 3 divided and arranged in a large number in the furnace length direction is set sequentially higher from the pre-tropical zone toward the firing zone, and is sequentially set lower from the firing zone toward the cooling zone. . The output of the temperature sensor 8 is fed back to the heater 7 so that the temperature is accurately maintained. In the present invention, by changing the temperature of the levitation gas in the furnace length direction as described above, when the flat plate member P is conveyed from the furnace inlet to the furnace outlet while being levitated and held by the levitation gas, the flat plate member P is It becomes possible to give a predetermined temperature history. Since the heated air is blown directly onto the flat plate member P, the heat transfer coefficient is increased, and excellent thermal efficiency can be achieved.

  In order to float and hold the flat plate member P, the levitation gas is injected from the chamber 3 toward the lower surface of the flat plate member P. The injected levitation gas is applied to the end surface along the lower surface of the flat plate member P. It reaches the upper surface and finally fills the furnace chamber 2 to bring the furnace chamber 2 to the same temperature as the set temperature of the levitation gas. For this reason, even if a heater for heating the upper surface is not separately installed in the furnace chamber 2, the flat plate member P is heated from the upper and lower surfaces. In the roller hearth kiln, compared to the upper surface, there is a roller on the lower surface, so it was difficult to heat, but in the present invention, a floating gas for floatingly holding the flat plate member P is used as a heating source. It becomes possible to heat both upper and lower surfaces evenly. Needless to say, a heater for heating the upper surface can be separately installed in the furnace chamber 2.

  As shown in FIG. 2, the width of the chamber 3 constituting the buoyant gas jetting means may be equal to the furnace width, but the chamber 3 is also divided in the furnace width direction as shown in FIG. The temperature of the supplied heated gas can be changed in the furnace width direction. Since the flat plate member P is more easily heated and cooled at the end than at the center, for example, the temperature of the heated gas at the center is slightly higher than the temperature at the end in the heating process, and is slightly lower in the cooling process. Such operations are possible. The temperature difference in that case is about 5 to 50 ° C.

  The means for floating and holding the flat plate member P and imparting a temperature history has been described above, but actually means for conveying in the furnace length direction is required. In this embodiment, the conveyance roller 9 is brought into contact with and rotated on both sides of the flat plate member P, and is moved forward at a constant speed while regulating the position of the flat plate member P in the furnace width direction. In this case, there is an advantage that the driving unit 10 of the transport roller 9 can be provided outside the furnace, and a very small force such as a frictional force generated between the transport roller 9 and the edge of the flat plate member P in the floating state. The flat plate member P can be moved. However, in the present invention, the conveying means is not particularly limited, and various means such as a belt drive type and a chain type with a hook can be adopted.

  In addition, if the roller 9 for conveyance is arrange | positioned on both sides, if the width | variety of the flat member P changes, the space | interval of the roller 9 for conveyance must be readjusted. For this reason, it can also be set as the structure where the chamber 3 which comprises the floor surface of a furnace chamber inclines slightly in a furnace width direction, and the roller 9 for conveyance is arrange | positioned only below.

  As described above, since the heat treatment furnace of the present invention adopts the levitation holding method, heat treatment can be performed while transporting in the furnace without deforming or brazing the flat plate member without using a setter. it can. In addition, the heat treatment furnace of the present invention employs a system in which a predetermined temperature history is imparted to the flat plate member using the levitation gas as a heating source, so that it can be heated efficiently and evenly from both the front and back surfaces, and the temperature distribution Warpage due to non-uniformity can also be prevented.

It is a notional sectional view in the furnace length direction showing an embodiment of the present invention. It is a conceptual sectional view in the furnace width direction. It is a conceptual sectional view in the furnace width direction showing another embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Furnace 2 Furnace room 3 Chamber 4 Ejection means 5 Blower 6 Pipe line 7 Heater 8 Temperature sensor 9 Roller 10 for conveyance 10 Drive part

Claims (4)

  A heat treatment furnace for a flat plate member that performs heat treatment while transferring the flat plate member in the furnace length direction, and is provided with a jetting means for floating gas on the floor surface of the furnace chamber to float and hold the flat plate member. A flat plate member heat treatment furnace characterized in that the temperature of the working gas is changed in the furnace length direction and a predetermined temperature history is given to the flat plate member that is levitated and held by the levitation gas.   The flat plate member heat treatment furnace according to claim 1, further comprising a means for transferring a flat plate member that is levitated and held by a levitation gas at a side of the furnace chamber.   The levitation gas ejection means includes chambers divided in the furnace length direction, and each chamber is connected to a supply source of heated gas having different temperatures. Heat treatment furnace for flat members.   The levitation gas jetting means includes chambers that are also divided in the furnace width direction, and each chamber is connected to a supply source of heated gas having a different temperature. A heat treatment furnace for flat plate members according to claim 1.

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