JP2007247923A - Heat treatment device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat treatment device suitable for burning a phosphor film in the glass tube for a fluorescent lamp used in a back light, in particular, to transport a guide pipe in which a glass tube is put, by an endless chain and to continuously rotate the guide pipe. <P>SOLUTION: This heat treatment device has a pair of supporting part links having holes for loosely fitting a guide pipe 1, and comprises a roller 17 and a rail 18 constituting a transporting device for transporting the guide pipe in one direction in a heating furnace in the direction vertical to its shaft, and a chain traveling in the direction opposite to the transporting device. The heating furnace has an air circulation passage including an air suction opening 38 formed on one of side faces of the transporting device, and a sheathed heater 40 disposed in the air circulation passage. On the chain travelling in the opposite direction, a roller 27 connecting the chain, travels on the other pair of rails 28, and kept into contact with a lower face of the guide pipe 1 supported through the hole loosely fitted to the link 14 at a specific zone in the furnace. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention heat-treats a glass tube having a small diameter in a heat-resistant guide pipe, for example, a glass tube having a phosphor film on its inner surface for producing a fluorescent tube used for a backlight of a liquid crystal display device, etc. The present invention relates to a heat treatment apparatus.

  A fluorescent tube of a fluorescent lamp used for a backlight of a liquid crystal display device is manufactured by forming a phosphor film on the inner surface of a glass tube having a small diameter of about 2 to 4 mm. For this phosphor film, a paste obtained by adding a resin binder, an organic solvent for the binder, and other additives such as a film-forming preparation agent to the phosphor powder is applied to the inner surface of the glass tube, and the coating film is subjected to a predetermined heat treatment. Is formed.

  The heat treatment comprises a degreasing process for burning and removing the resin binder and the like by heating to a temperature of 150 to 350 ° C. in an air atmosphere after the coating film is dried, and a baking process for heating and baking to a temperature of 500 to 650 ° C. .

  The glass tube used here has a length of about 500 to 1500 mm, starts softening at about 500 ° C., and warps and strains at a firing temperature of 500 to 650 ° C. Therefore, the glass tube to be heat-treated is put in a heat-resistant guide pipe having a larger diameter, for example, a quartz tube having a diameter of about 20 mm, and the guide pipe is rotated, thereby rotating the glass tube. A method of heat treatment is employed.

A conventional heat treatment apparatus of this type is configured by a heating furnace in which a hot plate is arranged above and below a transfer device that transfers a glass tube, and a mechanism portion that rotates the glass tube is provided outside the hot plate. Therefore, the heating furnace is a teriyaki heating method from the top and bottom, and since the surroundings are in an open state, there is a problem that heat cannot be stored and heat radiation is large, it is easily affected by the outside, and uniform baking treatment cannot be performed. there were.
In the heat treatment apparatus, the glass tube is transported by a so-called walking method, and the guide pipe is lifted one by one by a jig from the rotating part and moved to the next step of one pitch. It was. Therefore, it cannot rotate when the guide pipe is lifted. Therefore, there is a disadvantage that warpage and distortion occur in the glass tube to be heat-treated in the guide pipe.

  Further, in the degreasing process, it is necessary to sufficiently feed air into the glass tube. In order to blow air into a small-diameter glass tube that rotates in the guide pipe, conventionally, a method has been adopted in which a nozzle that blows air faces the guide pipe. For this reason, there has been a problem that the apparatus becomes complicated, for example, the air blowing nozzle is operated in connection with the conveyance of the glass tube.

An object of the present invention is to provide a heat treatment apparatus capable of improving the thermal efficiency of the heat treatment in the degreasing step and the firing step as described above and performing a uniform heat treatment.
Another object of the present invention is to provide a heat treatment apparatus that can supply sufficient air into a glass tube and reliably perform degreasing.

  Furthermore, according to the present invention, the guide pipe can be freely and continuously rotated when the guide pipe is transported in the heating furnace. Therefore, even if the glass tube as the object to be processed is softened, the linearity is maintained. It aims at providing the heat processing apparatus which can be maintained.

  The heat treatment apparatus of the present invention includes a heating furnace and a transport device that transports the heat-resistant guide pipe in a direction perpendicular to the axis of the heating furnace in one direction, and the heating furnace is one of the transport devices. An air circulation path including an air inlet opening on the side surface of the air and an air outlet opening on the other side surface of the transfer device corresponding to the suction opening, and a heating device provided in the air circulation path And a blower provided in a path from the suction port to the blowout port.

This heat treatment apparatus has an air suction port that opens on one side surface of the transport device, and has an air outlet port that opens on the other side surface of the transport device corresponding to the air suction port. Hot air may be sent to a limited space where the apparatus moves. Therefore, the air is heated by the heating device provided in the air circulation path, and this is circulated by the blower to the air circulation path in the substantially sealed space except for the inlet and the outlet of the transfer device, so that the heat efficiency Can be improved.
If the heating device is provided so as to heat the conveying device in the air circulation path, the guide pipe moving in the furnace can also be heated, so that the thermal efficiency is further improved.

  In addition, the air blower is provided in the path from the air suction port to the blowout port, and has a method of sucking air from the air suction port that opens on the side surface of the transport device, so the air blowout port provided corresponding to the suction port Thus, air can be easily fed into a thin glass tube which is an object to be processed in the guide pipe. For this reason, degreasing | defatting of the fluorescent substance film in a glass tube can be performed uniformly over the full length of a glass tube. Further, since a complicated mechanism for operating the air blowing port to face the guide pipe is not required, the configuration of the apparatus can be simplified. Therefore, a degreasing process can be implemented efficiently. In this method of sucking air, it is preferable that the air in the guide pipe is sucked by the suction force from the air suction port.

The present invention includes a heating apparatus, a pair of support portions having holes for loosely fitting a heat-resistant guide pipe, and a conveying apparatus that conveys the guide pipe in one direction in a direction perpendicular to the axis thereof, And a guide pipe rotating chain that runs in the opposite direction to the conveying device,
The heating furnace includes an air circulation path including an air inlet opening on one side surface of the transfer device and an air outlet opening on the other side surface of the transfer device corresponding to the suction port, the air A heating device provided in the circulation path, and a blower provided in a path from the suction port to the blowout port,
The guide pipe rotating chain is configured to contact a lower surface of a guide pipe supported by the transfer device in a specific section in the furnace.

In this heat treatment apparatus, the guide pipe is supported loosely in holes provided in the pair of support portions of the transport apparatus. And in the specific area in a furnace, the lower surface of a guide pipe contacts the chain | strand which travels in a direction opposite to a conveying apparatus. At this time, the guide pipe rotates in the hole of the support portion due to friction with the chain.
In order to make the lower surface of the guide pipe come into contact with a chain that runs in the opposite direction to the conveying device, the rail for running the guide pipe rotating chain has a chain push-up portion whose height is increased in the specific section. It is preferable that the guide pipe rotating chain travels along the chain push-up portion to rotate in contact with the guide pipe.
Since the guide pipe can be continuously rotated in the heating furnace by such a simple mechanism, the glass tube of the object to be processed in the guide pipe rotates, and thus warps and strains even when softened. There is nothing.

  In the heat treatment apparatus, the heating furnace may include a plurality of the air circulation paths along the moving direction of the transfer apparatus. By changing the set temperature of the heating device of each air circulation path, as the workpiece is transported by the transport device and progresses through the furnace in sequence, the temperature is raised sequentially, or the temperature is lowered gradually from the raised temperature can do.

  In the above heat treatment apparatus, the air circulation path may include an exhaust part having a damper and an outside air intake part having a damper between the air suction port and the air blowing port. By appropriately opening and closing the dampers of the exhaust part and the outside air intake part, by replacing a part of the air in the furnace with the outside air, it is possible to prevent accumulation of contaminated air and contribute to temperature control.

  Since the heating device of the present invention heats the guide pipe supported and moved by the conveying device by circulating hot air, the thermal efficiency is improved. In addition, air (hot air) can be uniformly fed into the workpiece in the guide pipe. Therefore, it is suitable for degreasing the fluorescent substance film in the glass tube for fluorescent lamps used for a backlight.

In addition, the heat treatment apparatus of the present invention includes a transport device having a pair of support portions having holes for mating guide pipes, and a guide pipe rotating chain that runs in the opposite direction to the transport device. It can be conveyed while rotating the guide pipe with a simple mechanism. Therefore, it is suitably used for firing a phosphor film for backlight that has undergone a degreasing process.
Furthermore, according to the said conveying apparatus, an endless drive is possible with mounting a guide pipe. That is, continuous operation can be performed by intermittently stopping the conveying device and discharging a processed object such as a processed glass tube and inserting a new processed object into the guide pipe.

A preferred embodiment of the heat treatment apparatus of the present invention is shown in FIGS.
The heat treatment apparatus 10 shown here includes a base portion 11 and a heating furnace 30 provided on the base portion 11. The base portion 11 is provided with a chain conveyor 12 for transporting a heat-resistant guide pipe into which the object to be heat-treated is placed, and sprockets 13a, 13b, 13c and 13d on which the chain conveyor 12 is stretched. The sprocket 13a is connected to a drive shaft of a motor (not shown) by a chain, and drives the chain conveyor 12 in the direction of the arrow in the figure. The chain conveyor 12 moves in the direction of arrow A in FIG. 1 intermittently, for example, moving for 8 seconds / stopping for 4 seconds. The driving speed of the chain conveyor 12 is, for example, about 600 mm / min.

  The heating furnace 30 provided on the base portion 11 includes an outer frame having a bottom portion 31 and a furnace body upper portion 32 having a substantially U-shaped cross section surrounding the chain conveyor 12 running on the bottom portion 31 from the top and side surfaces. Become. The upper part 32 of the furnace body is closed except for the front part and the rear part, which have an inlet 33 and an outlet of the chain conveyor 12. The outer frame of the heating furnace 30 is composed of a heat insulating material and a stainless steel plate covering the heat insulating material.

  In this example, the heating furnace 30 is configured by connecting six furnaces 34A, 34B,... 34E and 34F, and each furnace is partitioned by a partition wall except for a passage portion through the chain conveyor. Although the internal configuration of each furnace is substantially the same, the temperature of the air circulating through the air circulation path can be changed independently. As a representative, the configuration of the furnace 34A will be described below with reference to FIG.

  The internal space portion surrounded by the outer frame of the furnace 34A is partitioned by a partition wall 35 into a lower space portion 36 and an upper space portion 37, and both space portions communicate with each other at the side surface portion to constitute an air circulation path. . That is, the lower space 36 is formed by an air suction port 38 that opens on the side surface of the chain conveyor 12 that runs on the bottom 31 and an air outlet 39 that opens on the other side of the chain conveyor 12 so as to face the air suction port 38. And the upper space portion 37 communicate with each other.

  In the present embodiment, the air in the guide pipe is sucked by the air suction force of the air suction port 38, whereby the air is smoothly distributed to the guide pipe and the glass tube therein. For this purpose, the opening area of the air suction port 38 is preferably smaller than the opening area of the air blowing port 39. In this example, the air outlet 39 includes a louver.

  The air suction port 38 is at a position facing the opening end of the guide pipe 1 supported by the chain conveyor 12, the vertical length is slightly smaller than the diameter of the guide pipe 1, and the horizontal length is on the chain conveyor 12. It is preferable to have a rectangular shape that includes 10 to 15 guide pipes 1. The chain conveyor 12 may be driven continuously or intermittently. However, when the chain conveyor 12 is moved intermittently, the air suction port 38 corresponds to each of 10 to 15 guide pipes when the chain conveyor 12 stops. You may branch to the some opening part opened so that it may do.

  When the inner diameter of the guide pipe is 20 mm, the air suction port 38 is preferably a rectangle having a length of 30 mm and a horizontal length of 470 mm. The air outlet 39 is larger than the air inlet and preferably has a length of 70 mm and a horizontal length of 470 mm. Although depending on the inner diameter of the guide pipe, the air suction port 38 has a suitable length of 20 to 30 mm, and the air outlet 39 has a suitable size of 30 to 70 mm. The distance between the air blowing port and the opening end of the guide pipe 1 on the chain conveyor 12 depends on the diameter of the guide pipe 1, but is preferably about 30 to 50 mm, more preferably about 30 mm. The distance between the air outlet 39 and the opening end of the guide pipe may be the same as that of the air inlet.

  An exhaust cylinder 41 and a supply cylinder 42 are provided in the furnace body upper part 32 so as to communicate the upper space 37 and the outside. By appropriately opening and closing the damper of the exhaust cylinder 41 and the damper of the supply cylinder 42, the furnace By replacing a part of the air inside with the outside air, it is possible to prevent the accumulation of contaminated air and to contribute to temperature control. A blower block 43 is further attached to the furnace body upper part 32.

  As the heating means for heating the air in the air circulation path, a plurality of sheathed heaters 40 installed in the lower space 36 in parallel with the air circulation direction are used. In the illustrated example, the sheathed heater 40 passes through a portion that connects the air suction port and the air outlet and the upper space 37. The lower space 36 has a support member 47 that appropriately supports the sheathed heater 40.

  The blower block 43 includes a sirocco fan 44 disposed in a portion that partitions the upper space portion 37 and a motor 45 that drives the sirocco fan 44. The sirocco fan 44 circulates heated air through the lower space 36, the upper space 37, and an air circulation path constituted by an air suction port 38 and an air blowing port 39 that communicate with each other. The temperature in the air circulation path includes, for example, a temperature detector 46 provided in the upper space portion 37, a sheathed heater 40 based on the temperature detected by the temperature detector, dampers of the exhaust cylinder 41 and the supply cylinder 42, and the like. It is adjusted by the control device that controls In addition, by controlling the motor 45 that drives the sirocco fan 44 with an inverter, the air inflow speed at the air suction port 38 can be adjusted. Although depending on the size of the air suction port 38, the air inflow speed is suitably 3 to 10 m / sec.

  As described above, air having a predetermined temperature flows through the lower space 36 in the furnace 34A. And since the air suction port 38 is in the position facing the opening end of the guide pipe 1 held by the chain conveyor on the side surface of the chain conveyor 12, the air in the guide pipe 1 is sucked. The air in the glass tube 2 that is the object to be heat-treated is also sucked. For this reason, the air of the predetermined temperature which blows off from the blower 39 of air is suck | inhaled in the guide pipe 1 and the glass tube 2 in it.

  As described above, each of the furnaces 34A to 34F can circulate air at a predetermined temperature. For example, the furnace 34A and 34B sequentially perform the degreasing process so as to increase the temperature, and then from the furnace 34C. The degreasing step and the firing step can be carried out continuously, such as performing a firing step of raising the temperature up to the furnace 34D, holding the furnace 34E at a constant temperature, and finally cooling slowly in the furnace 34F.

Next, the structure for heat-treating the glass tube as the object to be processed in the baking step will be described.
The chain conveyor 12 as a conveying member integrally includes an attachment having a hole 15 in which the link 14 constituting the chain loosely engages the guide pipe 1. One end of the guide pipe 1 is supported by the pair of links 14 having such a structure. The pair of links 14 are connected to adjacent pairs of links by pins 16 one after another to form a chain, and a roller 17 is pivotally supported on each pin 16. The roller 17 travels on the rail 18 provided on the bottom 31. A pair of such rails 18 are provided on the bottom 31, and the guide pipe 1 is conveyed by a pair of chains that run on the rails.

On the other hand, another pair of rails 28 is provided inside the rail 18, and the guide pipe rotating chain 22 runs on the rails. The chain 22 includes a link 24, a pin 26 that connects the links 24 to each other, and a roller 27 that is pivotally supported by the pin 26. The upper surface of the link 24 is flat, and the guide pipe is rotated by bringing the upper surface of the link 24 into contact with the guide pipe 1 supported by the chain 12 as described below. That is, the chain 22 is driven in the opposite direction to the chain 12. The rail 28 for running the chain 22 has a chain push-up portion in which the rail height is slightly increased in the section H (FIG. 1) from the approximate center of the furnace 34C to the end of the furnace 34E.
Therefore, when the chain 22 runs on the chain push-up portion, the chain 22 slightly lifts the guide pipe 1 on its upper surface. As a result, the guide pipe 1 supported by the chain 12 floats slightly in the hole 15 and rotates in the direction of arrow C in FIG. 4 due to friction with the chain 22 moving in the opposite direction. In FIG. 4, the guide pipe 1 is drawn so as to be in contact with the edge of the hole 15 of the chain 12, but when the guide pipe rotates, the guide pipe 1 is slightly lifted by the chain 22 and is centered in the hole 15. Therefore, the rotation is not prevented by the chain 12.

  The diameter of the hole 15 in the link 14 of the chain 12 and the outer diameter of the guide pipe 1 are determined between the upper surface of the guide pipe and the upper inner surface of the hole 15 when the guide pipe 1 is slightly lifted in contact with the chain 22. The relationship is preferably such that a slight gap is formed. As a result, the guide pipe 1 can rotate due to friction with the chain 22. Before and after the section H, the rail 28 is inclined so as to change the height gently.

As the guide pipe 1 rotates as described above, the glass tube 2 having the phosphor film therein rotates by its own weight and tends to be positioned at the bottom of the rotating guide pipe 1. Even if the tube 2 is softened during firing, no warping or distortion occurs. In FIG. 4, the example which put the two glass tubes 2 in the guide pipe 1 is shown. When the glass tube 2 having an outer diameter of 4 mm is placed in the guide pipe 1 having an inner diameter of 20 mm, up to three glass tubes can be inserted if the number of rotations of the guide pipe is about 6 to 20 times / minute. Needless to say, one glass tube may be used, but two to three glass tubes are more efficient. However, if four or more glass tubes are put in the guide pipe 1 or if the number of rotations of the guide pipe is further increased, the glass tubes may be entangled with each other like a rope, so that the glass tube 2 put in the guide pipe 1 It is better to avoid further increasing the number of guides and further increasing the number of rotations of the guide pipe.
The length of the glass tube for manufacturing the fluorescent lamp for the backlight is about 600 to 1500 mm, and the length of the guide pipe is about 1000 to 1800 mm according to this.

  As described above, when the baking process is completed and the temperature reaches a low temperature in the furnace, the rail 28 is provided with an inclined portion that gradually decreases in height, and the guide pipe 1 is again in the hole 15 of the chain conveyor 12. Return to the original position.

  As described above, the chain conveyor 12 includes a pair of support portions having the holes 15 for mating the guide pipes. Therefore, as shown in the figure, the guide pipe can be held even when the support portion is made to be endless and the support portion faces downward, so that a special auxiliary member for holding the guide pipe is not required. Furthermore, since the chain conveyor 12 is driven intermittently, when the stop is taken out, if the baked glass tube is extracted from the guide pipe and a new glass tube is inserted into the empty guide pipe, degreasing is performed. A process and a baking process can be performed continuously.

The guide pipe is completely cooled while the chain conveyor 12 reaches the sprockets 13a to 13d.
Between the sprocket 13d and the furnace inlet 33, the fired glass tube is extracted from the guide pipe, and a new glass tube is inserted into the empty guide pipe. A push-up member 51 that pushes up a plurality of guide pipes is provided below the chain conveyor 12 so as to move up and down. On the other hand, above the chain conveyor 12, a plurality of pressing members 52, 53, and 54 for pressing, for example, four guide pipes are provided so as to be moved up and down by a pressing member 55.

When the chain conveyor 12 stops, the push-up members 51 and 55 are operated, and the guide pipes engaged with the support portions of the chain conveyor are sandwiched between the members 51 and the members 52, 53, and 54, respectively. Position the guide pipe at a certain position. Here, an extrusion bar is inserted into the guide pipe in contact with the member 52, and the internal glass tube is pushed out to a predetermined receiving portion. On the other hand, a new glass tube is inserted into the guide pipe in contact with the member 53 with a push-out bar. The glass pipe is aligned with respect to the guide pipe in contact with the member 54.
Thus, the glass tube can be processed continuously by intermittently driving the endless chain conveyor.

  The most preferred embodiment has been described above. However, various modifications are possible without impairing the features of the present invention. That is, in the above embodiment, the heat treatment apparatus has been described in which the degreasing process and the firing process of the glass tube having the phosphor film for producing the backlight of the liquid crystal display device are continuously performed. In this heat treatment apparatus, six furnaces are connected to constitute one heat treatment apparatus. Depending on the purpose, one or more of the furnaces described above constitute a heat treatment apparatus dedicated to the degreasing process or the firing process. can do.

As described above, the heating device of the present invention has good thermal efficiency and can send air evenly to the narrow tube in the guide pipe, so it is suitable for degreasing the phosphor film in the glass tube for a fluorescent lamp used for the backlight. is there.
Moreover, according to this invention, it can convey, rotating the guide pipe to convey for a predetermined area continuously. Therefore, it is suitably used for firing a phosphor film for backlight that has undergone a degreasing process.

  The heat treatment apparatus of the present invention can be applied not only to the manufacture of fluorescent lamps for backlights, but also to heat treatment for supplying heated air into the narrow tube and heat treatment of the object to be processed while continuously rotating the guide pipe. It is.

It is a side view which shows the schematic structure of the heat processing apparatus in one embodiment of this invention in the cross section. FIG. 2 is a sectional view taken along line 2-2 of FIG. It is an enlarged view of the principal part of FIG. It is a side view of the principal part of the chain used for the conveying apparatus. It is a side view of the principal part of the chain for guide pipe rotation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Guide pipe 2 Glass tube 11 Base part 12 Chain conveyor 13a-13d Sprocket 15 Hole 18, 28 Rail 22 Guide pipe rotation chain 30 Heating furnace 31 Bottom part 32 Upper part of furnace body 34A-34F Furnace 38 Air suction port 39 Air blowing port 37 Lower space 40 Sheath heater 43 Blower block 44 Sirocco fan

Claims (5)

A heating apparatus, a conveying device having a pair of support portions having holes for loosely fitting a heat-resistant guide pipe, and conveying the guide pipe in one direction in a direction perpendicular to the axis thereof, and the conveying device A guide pipe rotating chain that runs in the opposite direction to
The heating furnace includes an air circulation path including an air inlet opening on one side surface of the transfer device and an air outlet opening on the other side surface of the transfer device corresponding to the suction port, the air A heating device provided in the circulation path, and a blower provided in a path from the suction port to the blowout port,
The heat treatment apparatus, wherein the guide pipe rotating chain is configured to contact a lower surface of the guide pipe supported by the transfer device in a specific section in the furnace.   The guide pipe rotating chain includes a rail that travels, and the rail includes a chain push-up portion that is increased in height in the specific section, and the guide pipe rotating chain travels the chain push-up portion. The heat processing apparatus according to claim 1, wherein the guide pipe is rotated in contact with the guide pipe.   The heat treatment apparatus according to claim 1 or 2, wherein the heating furnace includes a plurality of the air circulation paths along a moving direction of the transfer device, and the specific section is continuously provided in one or more furnaces. .   The heat treatment apparatus according to any one of claims 1 to 3, wherein the air circulation path includes an exhaust portion having a damper and an outside air intake portion having a damper between the air suction port and the air outlet.   A heating apparatus, and a conveying device that conveys the heat-resistant guide pipe in a direction perpendicular to the axis of the heating furnace in one direction, and the heating furnace is configured to transfer air that opens to one side surface of the conveying device. An air circulation path including an air inlet and an air outlet opening on the other side of the conveying device corresponding to the inlet, an air blower provided in a path from the inlet to the outlet, and the air The heat processing apparatus characterized by having a heating apparatus which heats the said conveying apparatus in the circulation path of this.

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