JPH11125490A - Heat treatment system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure high quality heat treatment of a large work. SOLUTION: A heat treatment chamber 2 for a work W, a wind tunnel 4 formed through a heat storage plate 3, a temperature rising heater 5 being turned on upon temperature rise, and a normal hot air circulation system are arranged in a body 1. The heat treatment chamber 2 is provided, at the inlet and outlet thereof, with an air flow regulation plate 21 and a porous plate 22 while the wind tunnel 4 is provided with an wind tunnel inlet 41 and a porous plate 42 having smaller opening area than the porous plate 22. The heat storage plate 3 has a large number of vents 31. In case of a large work, the flow regulation plate is closed and hot air from the wind tunnel strikes against the lower surface of the work through the vents before being discharged from the porous plate 22. Since no wind flows on the upper surface of the work, the work can be fired with high quality and heat exchanging performance 15 enhanced through turbulence on the lower surface. Temperature of the work can be raised with good temperature distribution by means of the heat storage plate and hot air supply from a large number of vents. Temperature rising rate is increased by means of the temperature rising heater 5 and the efficiency of heat treatment is enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat treatment apparatus for heat-treating a flat article, and more particularly, it is effectively used for a heat treatment apparatus used in production equipment for LCD (liquid crystal display) glass substrates and the like.

[0002]

2. Description of the Related Art As a heat treatment apparatus for an LCD glass substrate or the like, an air circulation heating type apparatus (for example, Japanese Patent Application Laid-Open No.
No. 17514) is often used. In this apparatus, the glass plate was heated by flowing hot air controlled at a predetermined temperature along the glass surface in one direction in parallel with the glass surface. For this reason, the temperature rise of the glass sheet is increased quickly on the windward and slowed downwind, and the difference in the temperature distribution generated in the glass sheet results in variation in firing quality. In this case, if the glass sheet is of a normal size as in the prior art, the temperature difference between the glass sheet on the leeward side and the leeward side is relatively small, and the variation in sintering quality is within an acceptable range.

However, recently, in order to increase the screen size and cost of the liquid crystal display, the size of the mother glass tends to be increased in order to make it possible to take a large number of screens at one time. Technology development of large mother glass is also underway. When a large glass plate exceeding 1 meter square is fired in this way, even if the temperature on the leeward side rises to reach a predetermined temperature for heat treatment, the temperature on the leeward side is several tens of degrees lower than the predetermined temperature. A delay in temperature rise occurs, and variations in firing quality exceed allowable limits. In the case of performing high-quality heat treatment, there is a firing step in which hot air having a high flow velocity cannot be used due to the influence on the surface state of glass.

In such a glass firing step, a hot plate heating type apparatus (for example, JP-A-6-9726) is usually used.
No. 9). Hot plate
A large number of divided heating elements are formed in close contact with the back surface of a metal plate with high thermal conductivity whose surface is processed to a high degree of flatness, and uniformity is achieved by finely adjusting the heating value of each heating element. The surface temperature can be obtained.

[0005] However, such a hot plate is extremely expensive, and a hot plate having an area corresponding to a mother glass exceeding 1 square meter is difficult to equalize in terms of surface processing accuracy and the like. As a result, accurate temperature distribution cannot be achieved. Further, in order to enhance the heating efficiency and facilitate the temperature control of the mother glass itself, it is desirable to make the glass and the hot plate contact, but in order to suppress the peeling charge generated in the mother glass when separating the two, These are kept out of contact with a slight gap of about 0.2 mm. However, when the size of the mother glass is increased, even if the mother glass itself has good planar accuracy, the gap is not precisely maintained due to the thermal expansion distortion of the glass and the hot plate and the deflection of the glass under its own weight, and thus the separation charging can be prevented. Is gone.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems in the prior art and to provide a heat treatment apparatus which can heat-treat even large articles having good heat treatment quality.

[0007]

According to the present invention, there is provided a heat treatment apparatus for heat treating a flat article by circulating a heated gas.
A heat treatment chamber for heat-treating the article, wherein the heat treatment chamber has an opening / closing plate which is open at one end face and can be opened and closed, and has an outlet opening at the other end face; and a partition member below the heat treatment chamber. One side opening at a position corresponding to the one side end surface and another side resistance plate at a position corresponding to the other side end surface, the other side resistance plate having an opening area smaller than that of the outlet opening. And a plurality of conducting portions provided on the partition member so as to conduct the parallel space and the heat treatment chamber.

The invention according to claim 2 is characterized in that, in addition to the above, a heating means is provided on the side of the parallel space of the conducting portion. According to a third aspect of the present invention, in addition to the features of the first aspect, the partition member is a heat storage plate having a large heat capacity.

[0009]

FIG. 1 shows an example of the overall configuration of a heat treatment apparatus to which the present invention is applied. The heat treatment device circulates hot air, which is a heated gas, to produce a flat article LCD.
An apparatus for heat-treating a work W such as a glass substrate. A heat treatment chamber 2 for heat-treating the work W is provided in a container-shaped main body 1 surrounded by a heat insulating wall 1a, and a heat storage plate 3 serving as a partition member below the heat treatment chamber 2. A wind tunnel 4 as a parallel space formed in parallel with the heater, a heating heater 5 used in heating the work as heating means provided therein, and the like.

In the main body 1, as in the ordinary heat treatment apparatus, the main heater 6, the blower 7, the air supply duct 8, the high-performance filter 9, the plenum chamber 10, the heat treatment chamber 2, the wind tunnel 4, the intake duct 11, and the like. The air is heated to a temperature of about 230 ° C. for heat-treating the work W and circulated. The heat treatment room 2
May be provided in one stage, but in this example, six stages are arranged in the vertical direction in order to increase the processing efficiency.

Although not shown, a heat insulating door is provided on the front side of the main body 1 on the front side of the paper, and an opening for entering and exiting the work is provided at a position corresponding to the work W at each stage. A moving door for opening and closing the door is provided for each stage. The work W is supported at an appropriate height by projecting a plurality of pins and the like from the heat storage plate 3 (not shown). An operation control panel for operating and controlling various devices is also provided at an appropriate position. The temperature control of the main heater 6 and the heating heater 5 and the like are also performed by this operation control panel.

The heat treatment 2 is provided with an air volume adjusting plate 21 which is an opening / closing plate having an open end on one side, and a perforated plate 22 having an outlet opening on the other end. The air volume adjustment plate 21 can open and close the opening from fully open to fully closed. The perforated plate 22 is connected to the intake duct 11.
This is a plate having a large aperture ratio and a low air passage resistance that can prevent backflow of turbulent airflow from the side.

The wind tunnel 4 has a wind tunnel entrance 41 as one side opening and a perforated plate 42 at the wind tunnel exit as the other side resistance plate at positions corresponding to one end and the other end of the heat treatment chamber 2, respectively.
And The opening area of the perforated plate 42 is considerably smaller than that of the perforated plate 22. As described above, the heat treatment chamber 2 and the wind tunnel 4 which are formed in six stages are partitioned by the partition plate 12 together with the heat storage plate 3, and each is a space arranged in parallel with each other.

The heat storage plate 3 is made of a plate having an appropriate thickness and a large heat capacity, such as a metal such as stainless steel, and has a plurality of ventilation holes 31 as conducting parts. The ventilation holes 31 are formed in a suitable shape such as a round hole, a square hole, and a long hole, and are penetrated through the entire surface of the heat storage plate 3 in an appropriate arrangement such as a grid pattern or a staggered shape. Although not shown, the heat treatment chamber 2 of the heat storage plate 3 is not shown.
Grooves are provided on the side surface in a lattice shape to increase the surface area and turbulently flow the hot air flowing on the surface, thereby improving the heat exchange rate. Although the heat storage plate 3 may be arranged in parallel with the wind tunnel 4 as shown in FIG. 1, it is desirable to arrange the heat storage plate 3 at an inclination as shown in FIG. With this configuration, even if the flow rate of the hot air is accumulated in the flow direction and increases, the flow velocity does not become excessive and the hot air easily passes through the lower surface of the work W.

The temperature raising heater 5 is provided in the wind tunnel 4 at the inlet of the vent hole 31 of the heat storage plate 3. This heater has a small capacity such that the temperature of the portion of the hot air circulated and heated by the main heater 6 that enters the ventilation hole 31 is raised by several degrees when the temperature of the workpiece is raised. It is turned on / off at a predetermined timing by a control device (not shown).

The above heat treatment apparatus is operated as follows. The work W is placed in all the heat treatment chambers 2 of the six stages, and the temperature to be heat treated is, for example, 230 °.
In a steady operation state in which the temperature reaches about C, the heater 6 and the blower 7 of the hot air circulation system are operating, and
The hot air is circulated inside. The heating heater 5 is off. The work W is supported on the heat storage plate 3 at an appropriate distance from it. In a non-winding operation for heat-treating a large mother glass or a work requiring high-quality baking without wind, the air volume adjusting plate 21 is fully closed.

In a steady state in such a windless operation, the hot air enters the wind tunnel 4, but the opening area of the perforated plate 42 at the outlet thereof is considerably smaller than the opening area of the perforated plate 22 at the outlet of the heat treatment chamber 2. The hot air entering 4 is a perforated plate 42
Makes it difficult to pass through this portion, and the pressure in the wind tunnel 4 increases. On the other hand, since the air volume adjusting plate 21 is fully closed, the pressure in the heat treatment chamber 2 is low. As a result, hot air flows into the heat treatment chamber 2 from the wind tunnel 4 through the ventilation holes 31 of the heat storage plate 3. Such an inflow amount of hot air is determined to be an appropriate amount in an actual apparatus by appropriately determining the opening areas of the perforated plates 22 and 44.

In this state, the work is heat-treated, and when a predetermined heat treatment time elapses for the work in any one of the heat treatment chambers, the work is unloaded and a new work is loaded instead. The loading / unloading of the work is performed by a robot hand or the like provided in an external work transfer system.
The work after the firing step is sent to the next step. The heat treatment chambers 2 formed in multiple stages in the main body 1
Is closed, so that the loading and unloading of the work in any stage does not disturb the temperature in the other stages.

When a new work is carried into the heat treatment chamber 2, hot air is circulated at this time as in the steady state.
The air volume adjusting plate 21 is in a fully closed state. Therefore, the hot air passes through the ventilation holes 31 and flows into the heat treatment chamber 2 having a low pressure from the wind tunnel 4 having a high pressure. After the hot air collides with the back surface of the work W, most of the hot air flows on the back surface side of the work W in the exit direction. At this time, the hot air flowing from the large number of air holes 31 collides with the back surface of the work W, collides with the hot air already flowing, mixes, and furthermore, a lattice-like groove formed on the surface of the heat storage plate 3 and the like. It is turbulent and mediates extremely efficient heat exchange between the work W and the heat storage plate 3.

In this case, since the temperature of the newly-loaded work is low, the hot air heats the work and lowers the temperature. However, heat is immediately absorbed from the heat storage plate 3 by the turbulence effect,
Heat the work while recovering the temperature. And the heat storage plate 3
Is heated by circulating hot air and has a uniform temperature distribution, and its heat capacity is sufficiently large so that hot air can be heated at almost the same temperature and even if heat is applied to the work via hot air, The temperature drop is slight. Further, in the flow direction of the hot air along the work, hot air having substantially the same temperature that has passed through the ventilation holes 31 is sequentially supplied. As a result, even a low-temperature work is heated uniformly in the flow direction of hot air, and the temperature is raised while maintaining a substantially uniform temperature distribution. In addition, the temperature of the work quickly rises due to the turbulence effect.

Further, in this embodiment, a heating heater 5 is provided, which is turned on in conjunction with the loading of the work, and further heats the hot air passing through the ventilation holes 31 by several degrees. As a result, the temperature difference between the hot air and the workpiece increases, and the rate of temperature rise of the workpiece can be increased. In particular, when the temperature of the work approaches the heat treatment temperature, the temperature difference with the hot air usually approaches, the amount of heat exchange is greatly reduced, and the temperature rise time is significantly longer, but when the hot air is reheated as in this example, Even in such a case, a certain temperature difference is maintained between the workpiece and the workpiece, and the time required for raising the temperature, that is, the heat treatment time can be shortened, and the processing efficiency can be increased.

When the work reaches the heat treatment temperature, the heating heater 5 is turned off. Since the temperature at which the workpiece is to be heat-treated has a certain allowable range, it is desirable to turn off the temperature raising heater 5 at a lower temperature among the heat treatment temperatures. Thereafter, the work is adjusted to and maintained at the heat treatment temperature by the circulating hot air. At this time, since the work has reached the heat treatment temperature, the work itself hardly absorbs heat, the heat loss of the circulating hot air from the main body 1 to the outside is compensated by the main heater 6, and the hot air is maintained at a constant temperature. You.
As a result, during such temperature keeping, the temperature distribution of the work is further improved.

After the heat treatment of the work in any one of the heat treatment chambers is completed, when the heat treatment time of the other work and the work of the other work further elapses, the work is similarly loaded / unloaded in each work. Will be Therefore, when the heat treatment chambers are provided in multiple stages as in this example, the heat treatment of the workpiece is sequentially completed at short time intervals, and the heat treatment efficiency is improved.

As described above, even when the air volume adjusting plate 21 is fully closed, the work can be heat-treated by blowing hot air from the lower surface side of the work. Then, only a small amount of hot air that has passed through both side ends from the lower surface side of the work flows around on the upper surface side of the work, so that the upper surface side of the work is almost in a calm state. The heat treatment chamber 2 itself is the main body 1
Since there is a hot air atmosphere circulating in the inside, there is no heat dissipation from the upper surface of the work as in the case of simple hot plate heating. As a result, it is possible to perform a heat treatment with high baking quality close to no wind, and it is possible to satisfactorily heat-treat a work that cannot directly flow hot air.

The work is heated mainly from the lower surface of the work through the hot air, and the upper surface of the work is also in a hot air atmosphere as described above. The space between them is not brought close to a minute distance unlike heating. As a result, even if the work is large in size, it is possible to reliably prevent electrostatic damage of a circuit or the like formed on the work surface.

When the work has a normal size and hot air is allowed to pass through the surface of the work, the air volume adjusting plate 21 is set to an appropriate opening degree, and hot air is directly introduced into the heat treatment chamber 2. Even in this case, the opening area of the perforated plate 42 is
2, the hot air in the wind tunnel 4
1 also flows into the heat treatment chamber 2, whereby the back side of the work is also heated. As a result, the temperature of the work is quickly and uniformly increased, the temperature distribution is improved, and the heat treatment time is further reduced.

[0027]

As described above, according to the present invention, according to the first aspect of the present invention, the heat treatment chamber for heat-treating a flat article is provided with an opening / closing plate which has an open end on one side and which can be opened and closed. In addition, since the outlet opening is provided on the other end surface, by operating the opening / closing plate, the inside of the heat treatment chamber can be set to any of the no-air state or the normal heated gas blowing state. As a result, in the case of a large article or an article requiring high-quality firing, the heat treatment chamber can be kept in a windless state by closing the opening / closing plate. On the other hand, in the case of other ordinary articles, the heating gas can be introduced into the heat treatment chamber by opening the opening / closing plate, and the article can be subjected to heat treatment while shortening the temperature rise time. That is, such a selection is made possible by the open / close plate. It should be noted that it is easy to hold the opening / closing plate at an appropriate opening position, so that an appropriate breeze can be flowed into the heat treatment chamber, and depending on the article, such ventilation may be good. is there.

Next, a parallel space is provided below the heat treatment chamber via a partition member, a one-side opening is provided at a position corresponding to one end face of the heat treatment chamber, and the heat treatment chamber is provided at a position corresponding to the other end face of the heat treatment chamber. Since the other side resistance plate having an opening area smaller than the outlet opening is provided, and furthermore, a plurality of conducting portions are provided in the partition member, when the opening and closing plate of the heat treatment chamber is closed, heated gas enters from one side opening of the parallel space, This enters the heat treatment chamber through the plurality of conducting portions of the partition member, and can form a gas flow that exits from the opening of the heat treatment chamber.
Also at this time, since the opening / closing plate is closed, the upper surface side of the article is maintained in a state of almost no wind.

Since a flat article is put into the heat treatment chamber for heat treatment, the gas flow as described above causes the heated gas having passed through the plurality of conducting portions to hit the lower surface of the article and flow along the lower surface side of the article. The article can be heated from the lower surface side with the upper surface side substantially in a windless state. As a result, in the firing step in which the heating gas with a high flow rate is not applied to the surface of the article, which is the firing surface, firing is performed from the lower surface side to the upper surface side of the article, and the firing quality is not affected by the flow rate of the heating gas. High heat treatment.

In this case, the heated gas collides with the article to pass through the conductive portion of the partition member, and flows from a plurality of conductive members. Therefore, the heated gas flowing on the lower surface side of the article collides and mixes with each other. In addition, the flow of the heated gas becomes turbulent, and the heat exchange efficiency is improved. As a result, the temperature of the article can be increased quickly. Further, since the heating gas can be supplied uniformly by the plurality of conducting portions, a large temperature difference cannot be generated between the heating gas on the upstream side and the downstream side of the article as in the related art. The temperature distribution can be improved.

According to the second aspect of the present invention, in addition to the above, since the heating means is provided on the side of the parallel space of the conducting portion, the temperature of the circulating heated gas can be increased and the gas can be passed through the conducting portion. As a result, when the temperature of the article approaches the temperature to be heat-treated at the time of temperature rise, it is possible to secure a certain temperature difference between the article and the heated gas, increase the rate of temperature rise of the article, and increase the heat treatment efficiency. it can.

According to the third aspect of the present invention, in addition to the first aspect of the present invention, the partition member is a heat storage plate having a large heat capacity. The temperature hardly drops. As a result, even when the temperature of the article is raised, the article is uniformly heated, and the temperature distribution can be further improved.

In this case, the heat treatment chamber in which the articles are placed is under the atmosphere of the circulated heating gas, and heat exchange between the heat storage plate and the articles is performed through the heating gas on the lower surface side of the articles. The articles may be arranged at an appropriate distance from the heat storage plate. Therefore, unlike the conventional hot plate heating, there is no need to bring the article and the heat storage plate close to each other, and even in the case of a large-sized article, the problem of peeling charging can be solved and heat treatment can be performed safely.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an example of a heat treatment apparatus to which the present invention is applied.

FIG. 2 is an explanatory diagram showing an arrangement relationship between a heat storage plate and a work of the apparatus.

[Explanation of symbols]

 2 Heat treatment room 3 Heat storage plate (partition member) 4 Wind tunnel (parallel space) 5 Heating heater (heating means) 21 Air flow adjusting plate (opening / closing plate) 22 Perforated plate (outlet opening) 31 Vent hole (plurality of conducting portions) 41 Wind tunnel entrance (one side opening) 42 Perforated plate (other side resistance plate) W Work (flat article)

Claims (3)

[Claims] 1. A heat treatment apparatus for heat-treating a flat article by circulating a heated gas, comprising: a heat treatment chamber for heat-treating said article, an opening / closing plate having an open end on one side and capable of opening and closing the heat treatment chamber. And a heat treatment chamber having an outlet opening on the other side end face, and one side opening and the other side end face at positions corresponding to the one side end face formed in parallel with a partition member below the heat treatment chamber. And a parallel space provided with a second resistor plate having a smaller opening area than the outlet opening at a position where the other space is provided, and the partition member is provided so as to conduct the parallel space and the heat treatment chamber. A heat treatment apparatus comprising: a plurality of conducting portions. 2. The heat treatment apparatus according to claim 1, wherein heating means is provided on the side of the parallel space of the conduction portion. 3. The heat treatment apparatus according to claim 1, wherein the partition member is a heat storage plate having a large heat capacity.