KR20070088359A - Heating method for plate materials and retaining device for heating of plate materials - Google Patents

Abstract

A method and an equipment that can uniformly heat plate materials within a short time and a retaining device for uniformly heating the plate materials within a short time are provided. An equipment for heating of plate materials comprises: a heating furnace(1) that is a roller hearth type continuous kiln; a conveyor(3) installed inside a furnace body made of a heat-insulating material; and a retaining device(4) in which a heating target is retained by the roller conveyor, and which sequentially passes through the heating furnace to fore(heat) the heating target. A retaining device for heating of plate materials comprises: a plate retaining member(7) installed on a base(5) having a plurality of holes perforated therein to retain a glass substrate(6) as the heating target; and a radiation sheet retaining member(9) installed on the base to retain radiation sheets(8), wherein the radiation sheets are made from a stainless steel foil which has a thickness of 50 to 100 mu, and an oxide film formed thereon. The heating furnace comprises a hot air exhaust port(10) installed at an upper side of the retaining device, a heater(heat source) disposed at a lower side of the roller conveyor, and a fan(12) for blowing hot air to the exhaust port through a circulation channel(13) and a filter(14).

Description

HEATING METHOD FOR PLATE MATERIALS AND RETAINING DEVICE FOR HEATING OF PLATE MATERIALS}

1 is a cross-sectional view of a heating furnace in a first embodiment of a heating method of the present invention.

2 is a partial cross-sectional view of an embodiment of a glass substrate holding apparatus of the present invention.

Figure 3 is a schematic diagram of the arrangement of the radiation plate and the temperature distribution of the glass substrate during heating according to the present invention.

4 is a graph showing a temperature change of a glass substrate heated by the heating furnace of FIG. 1.

Fig. 5 is a schematic view showing an alternative of the radiation plate arrangement according to the present invention.

6 is a cross-sectional view of a heating furnace in a second embodiment of the heating method of the present invention.

* Explanation of symbols for the main parts of the drawings

1, 1 ': heating furnace

4, 4 ': retaining device

6: glass substrate (plate material)

7, 7 ': plate holder

8: copy

9, 9 ': Copy holder

11: Heater (heat source)

18: prop

20: pressing plate

TECHNICAL FIELD This invention relates to the heating method and heating apparatus of a board | plate material, and the holding apparatus for heating a board | plate material.

The heating of a board | plate material may be needed like the baking process in glass substrate manufacture of a flat-panel display. The heating of such a board | plate material is conventionally described in patent document 1 and patent document 2, and the hot air circulates through the holding apparatus (tray, cassette, etc.) which hold | maintained the board | plate, for example by a roller conveyor. It was performed by passing the inside of a heating furnace. Usually, in such a heating furnace, a some board | plate material is hold | maintained in parallel with the flow direction of a hot air by a holding apparatus at regular intervals. Moreover, as described in patent document 1 and patent document 2, a blowout port is provided in the upper part of a heating furnace, and hot air blows down from a blower outlet in many cases.

In the heating method of the conventional board | plate material, a board | plate material is heated up by the heat conduction from the hot air (air) which contacted (forced convection heat transfer). Since hot air deprives heat of a board | plate material, temperature becomes low on the downstream side from a blower port. Thereby, as for a board | plate material, temperature becomes hard to rise so that it is the downstream side of the flow direction of a hot wind, and a temperature difference arises in an upstream side and a downstream side.

In recent years, especially in manufacture of a flat panel display device, it is desired to heat a board | plate material uniformly. Since the convective heat transfer from the hot air to the plate becomes larger as the temperature difference between the hot air and the plate increases, the temperature difference between the upstream side and the downstream side decreases when the temperature of the plate approaches the take-out temperature of the hot wind. In other words, when the plate is kept in the furnace for a long time, the entire plate is heated up to a temperature substantially equal to the hot air extraction temperature, and the temperature difference between the upstream side and the downstream side of the plate is eliminated. However, the longer the time required for heating, the longer the length of the heating device, the higher the cost of the device, and the shorter the length of the heating device, the lower the number of sheets of sheet material that can be processed. There was problem to say.

(Patent Document 1)

Japanese Patent Application Laid-Open No. 11-311484

(Patent Document 2)

Japanese Patent Application Laid-Open No. 2005-114284

In view of the above problems, it is an object of the present invention to provide a heating method capable of uniformly heating a plate in a short time and a holding device for uniformly heating the plate in a short time.

MEANS TO SOLVE THE PROBLEM In order to solve the said subject, the heating method of the board | plate material by this invention hold | maintains several board | plate materials in parallel, hold | maintains the thin plate-shaped or thin-shaped copy boards between the said board | plate materials, and the said in a heating furnace Hot air is passed through the plate and the radiation plate, and the plate is heated by convective heat transfer of the hot air and radiant heat from the radiation plate.

According to this method, a board | plate material is heated not only by the forced convection heat transfer of hot air, but also by the radiant heat from the radiation board heated by hot air. For this reason, the temperature increase rate of a board | plate material is fast, and the whole board | plate material can be heated to predetermined temperature in a short time.

Moreover, in the heating method of the board | plate material of this invention, you may hold | maintain the said radiating plate facing the said hot air downstream of the said board | plate material.

According to this method, since the radiation plate is disposed only on the downstream side where the temperature of the hot air decreases compared to the upstream side and the amount of convective heat transfer to the plate is reduced, only the downstream side receives radiant heat from the radiation plate. As a result, the difference in heat transfer amount due to convective heat transfer between the upstream side and the downstream side of the plate is compensated for by the radiant heat from the radiation plate, so that the difference between the temperature rise rate on the upstream side and the downstream side of the plate becomes small, and the plate is short-lived. Can be heated uniformly.

Moreover, in the heating method of the board | plate material of this invention, you may hold | maintain the said radiating plate so that it may not oppose to the edge part on the side of the said hot air upstream of the said board | plate material, and the edge part near the heat source of the said heating furnace. .

According to this method, the radiant heat from the radiating plate can be transmitted only to a portion of the plate which is low in temperature and low in heat transfer due to convection of hot wind, and is not heated even by radiant heat from the heat source of the furnace. The difference of the temperature increase rate of becomes small and more uniform heating is attained.

Moreover, in the heating method of the board | plate material of this invention, the said radiation plate may be stainless steel foil in which the oxide film was formed in the surface of 100 micrometers or less in thickness.

According to this method, since stainless steel with high heat resistance is used as a radiation plate, it can apply to the heating at high temperature. In addition, when a foil having a thickness of 100 µm or less is used as the radiation plate, since the heat capacity of the radiation plate is small, the heating amount due to convective heat transfer is not reduced without decreasing the temperature of the hot air. In addition, by forming an oxide film on the surface of the radiation plate, the emissivity is high, and the heating efficiency due to radiation is high.

Moreover, the heating apparatus of the board | plate material by this invention makes it pass so that the holding apparatus which hold | maintains a thin plate-shaped or thin-shaped copy board in parallel between several board | plate materials, and between the said board | plate material and the said radiation board may pass. It shall be comprised as a heating furnace which circulates hot air.

According to this structure, a board | plate material and a radiation plate can be heated by convective heat transfer of hot air, and a board | plate material can be heated further by the radiant heat from the heated radiation board. Thereby, a board | plate material can be heated in a short time.

Moreover, according to this invention, the holding apparatus which hold | maintains the board | plate material heated in a heating furnace is the board | plate holder which hold | maintains several board | plate materials in parallel, and between the said board | plate material, and both sides, in parallel with the said board | plate material. It is supposed to include a copy plate holder for holding a thin plate shape or a thin copy plate, respectively.

According to this structure, a copy board can be made to face a board | plate material, and can be hold | maintained. Thereby, since a board | plate material can be heated also by the radiant heat from a radiation board in addition to the convective heat transfer from hot air, a board | plate material can be heated in a short time.

Moreover, in the holding device of the present invention, the copy plate holder comprises a plurality of struts standing upright on both sides of the holding device, and a plurality of pressing plates for sandwiching the copy plate with the struts, respectively. Also good.

According to this structure, even if it is a radiation plate with low mechanical strength like metal foil, it can be reliably held between plate materials. Moreover, the vertical length of a radiation plate and the vertical position to hold | maintain can be changed easily, and radiant heat can be selectively given to the part from which the hot air temperature becomes low, and a board | plate material can be heated uniformly.

In the holding apparatus of the present invention, the copy plate holder may hold the copy plate against the lower side of the plate member.

According to this configuration, the hot wind is lowered when hot air is blown out from the top of the plate, but the radiant heat from the radiating plate is applied only to the bottom of the plate, whereby the top and bottom temperature difference of the plate can be reduced.

Moreover, in the holding apparatus of this invention, the said radiation plate may be stainless steel foil in which the oxide film was formed in the surface of 100 micrometers or less in thickness.

According to this structure, a board | plate material can be heated efficiently using the radiation board which withstands high temperature, has a small heat capacity, and has a high emissivity.

EMBODIMENT OF THE INVENTION Hereafter, embodiment of this invention is described, referring drawings.

In FIG. 1, 1st Embodiment of the heating method of the board | plate material of this invention is shown. Although this embodiment uses the heating furnace 1, the heating furnace 1 is a well-known roller hearth type continuous kiln and the furnace body 2 which consists of a heat insulating material. The roller conveyor 3 is installed in the interior of the roller conveyor 3, and the holding device 4 in which the heating object is held by the roller conveyor 3 is sequentially passed through the heating furnace 1 to continuously fire (heat) the heating object. will be.

The holding device 4 which is itself an embodiment of the present invention is a plate holding holding a glass substrate 6 which is a heating target plate on a base 5 on which a plurality of holes are opened so that hot air can pass therethrough. A spherical plate 7 and a copy plate holder 9 for holding the copy plate 8 are provided. The radiation plate 8 consists of stainless steel foil of 50 micrometers to 100 micrometers in which the oxide film was formed in the surface. Moreover, the radiation plate 8 is wider than the glass substrate 6, has a height about half of the glass substrate 6, and is hold | maintained facing the center bottom vicinity of the glass substrate 6. In the heating furnace 1, the hot air blowout outlet 10 is provided above the holding apparatus 4, and hot air blows downward as shown by an arrow, and the clearance gap of the glass substrate 6 and the radiation plate 8 is formed. ), It blows straight to the lower part of the roller conveyor 3. The hot air blown out is heated again by the heater (heat source) 11 arranged below the roller conveyor 3, and the circulation flow path provided in the side in the furnace body 2 by the fan 12. Through (13), it is led to the upper part of the heating furnace 1, and it blows out from the blowout outlet 10 again through the filter 14. As shown in FIG.

2, the detail of the holding apparatus 4 is shown. The plate holder 7 is intended to hold the plurality of glass substrates 6 upright in parallel with each other. In addition, the radiation plate holder 9 attaches the radiation plate 8 to the glass substrate 6 on both sides of the front and rear sides of the glass substrate 6 at the center and both ends of the glass substrate 6 to be adjacent to each other. The uprights are opposed to each other, that is, the radiation plate 8 is held parallel to the glass substrate 6.

The plate holder 7 is provided with a lower holding block 15 fixed to the base 5 and a first frame fixed to the base 5 via a support to hold the lower end of the glass substrate 6. And an upper retaining block 17 fixed to the first frame 16 to hold the upper end of the glass substrate 6.

The copy plate holder 9 is composed of a plurality of struts 18 fixed upright on both sides of the base 5, and a pressing plate 20 fixed to the respective struts 18 with bolts 19, respectively. Both ends of each of the copy plates 8 are sandwiched and supported by the support posts 18 and the press plates 20, respectively. In addition, the props 18 are connected to each other by the second frame 21 in order to prevent the tip from being vibrated.

Next, the heating effect of the glass substrate 6 using the said heating furnace 1 and the holding apparatus 4 is demonstrated.

First, in FIG. 3, the model which simplified the heating method of this invention WHEREIN: The temperature distribution of the glass substrate 6 at the time of heating for a fixed time by hot air is shown. In FIG. 3, the radiation plate 8 is arrange | positioned between each glass substrate 6 and both sides so that it may face about three quarters of the hot air downstream of the glass substrate 6. When the glass substrate 6 and the radiation plate 8 of the normal temperature arranged in this way are heated by blowing hot air from above in the heating furnace 1, the glass substrate 6 and the radiation plate 8 are convection from the hot air. Heated by heat transfer.

In the graph of FIG. 3, the broken line shows the temperature distribution in the absence of the radiation plate 8. FIG. Since the temperature of the hot air which lost heat to the glass substrate 6 falls, as shown, the glass substrate 6 has a high temperature increase rate on the upstream side, and becomes high temperature on the upstream side. In addition, the temperature distribution at the time of placing the radiation plate 8 is shown by the solid line. When the radiation plate 8 is arrange | positioned, the radiation plate 8 similarly heats up by the convective heat transfer from hot air, and the radiation plate 8 which became high temperature performs the radiation which discharge | releases the heat as an electromagnetic wave. Since the glass substrate 6 is heated not only by the convective heat transfer from the hot air but also by the radiation of the radiation plate 8, the part facing the radiation plate 8 becomes high compared with the case by only the convection heat transfer from the hot air. . Thus, when the radiation plate 8 is arrange | positioned only in the downstream part from which the hot air temperature becomes low, the difference of the temperature rise of the upstream of the glass substrate 6 and the temperature rise of the downstream can be made small, and the upper and lower temperature difference can be made small.

In the embodiment shown in FIG. 2, the radiation plate 8 is not disposed not only at the upper end of the glass substrate 6 but also at the portion facing the lower end. 1, since the heater 11 is arrange | positioned under the glass substrate 6 as shown in FIG. 1, the vicinity of the lower end of the glass substrate 6 near the heater 11 radiates the radiant heat from the heater 11, and so on. It is because it does not need the radiant heat from the radiation board 8 because it receives and heats up. That is, the radiation plate 8 can minimize the temperature difference in the glass substrate 6 by arranging the radiation plate 8 on the hot wind downstream side of the glass substrate 6 so as to face only the portion away from the heat source.

4, the temperature change of the upper end part and the lower end part at the time of heating the glass substrate 6 with the holding apparatus 4 of FIG. The heating furnace 1 is divided | segmented into several vanishing | disappearance in the conveyance direction of the holding | maintenance apparatus 4, and it is set so that the taking-out temperature of the hot air in each vanishing | heating gradually increases. In FIG. 4, the temperature change of the lower end of the glass substrate 6 in the state which removed the radiation plate 8 is shown with a broken line, and the temperature change of the lower end of the glass substrate 6 at the time of attaching the radiation plate 8 is shown with a solid line. . The temperature of the upper end of the glass substrate 6 is not different depending on the presence or absence of the radiation plate 8. As shown in the drawing, the effect of the radiation plate 8 is seen when the hot air extraction temperature is 350 ° C. or higher, and as the temperature becomes higher, the effect of reducing the temperature difference between the upper end and the lower end of the glass substrate 6 is higher. have. This is because radiant heat is proportional to the square of temperature, and the radiation plate 8 shows that it is especially effective with respect to the heating at the high temperature of 400 degreeC or more.

In order not to reduce the temperature of a hot air, the radiation plate 8 needs to have a small heat capacity, and a thin plate and foil of 100 micrometers or less in thickness are preferable. In addition, the radiation plate needs to withstand a high temperature of 400 ° C or higher, and is preferably formed of a metal, in particular, stainless steel. Moreover, since the radiation plate 8 has a high effect of heating the glass substrate 6, the higher the emissivity, it is preferable to form an oxide film on the surface of the stainless steel.

In addition, in this embodiment, as shown in FIG. 5, one copy board 8 is hold | maintained with respect to the glass substrate 6, ie, only one of the front and back sides of the one glass substrate 6 is shown. The copy plate 8 may be disposed to face each other. This is because the radiant heat of the radiation plate 8 is at least good when the difference in the amount of convective transfer heat in the upper and lower portions of the glass substrate 6 is small, such as when the temperature decrease of the hot air is small.

In addition, since the copying plate holder 9 of this embodiment is made to support the copying plate 8 between the support | pillar 18 and the pressing board 20, the material of the copying plate 8 consists of stainless steel foil. Even if the mechanical strength is low, it can be reliably maintained. In addition, the radiation plate holder 9 can easily and steadily maintain the radiation plate 8 even if the vertical length of the radiation plate 8 and the height to hold the radiation plate 8 change, so that the temperature of the hot air, the quantity of air, and the glass substrate In order to minimize the temperature difference of the glass substrate 6 according to various conditions, such as a physical property, it is easy to change the vertical length of the radiation plate 8, and the height to be maintained.

6, 2nd Embodiment of the plate heating method of this invention is shown. In FIG. 6, the same code | symbol is attached | subjected to the component which makes the function the same as 1st Embodiment, and description is abbreviate | omitted.

The heating furnace 1 'of this embodiment is comprised so that hot air may be blown | emitted in the horizontal direction with respect to the glass substrate 6. As shown in FIG. The holding member 4 'which conveys the inside of the heating furnace 1' by the roller conveyor 3 is the board | plate material holder 7 which laminates and holds the several glass substrate 6 horizontally at regular intervals. And a radiation plate holder 9 'for horizontally holding the radiation plate 8 between the glass substrate 6'.

Also in this embodiment, the operation | movement of the radiation plate 8 is the same as that of 1st Embodiment. In this embodiment, since the heater 11 is provided in the circulation flow path 13, the radiation plate 8 is arrange | positioned so that it may oppose to the edge part of the downstream side of the glass substrate 6. In addition, in the heating furnace 1 'which blows out the hot air horizontally, the glass substrate 6 and the radiation plate 8 may be held vertically.

According to this invention, when heating a board | plate material with hot air, a board | plate is hold | maintained between board | plate materials, and it can raise a board | plate material also by the radiant heat from a copy board. For this reason, a board | plate material can be heated immediately. In addition, by applying radiant heat only to a portion where the temperature of the hot air is lowered, the difference in temperature increase rate can be reduced, and the plate can be uniformly heated.

Claims (9)

The plurality of plates are kept in parallel, A thin plate-like or thin-shaped copy plate is held between the plate members, Hot air is passed between the plate and the radiation plate in a heating furnace, And the plate is heated by convective heat transfer of the hot air and radiant heat from the radiation plate. The method of claim 1, wherein the radiation plate is held opposite to the hot air downstream side of the plate. The method of claim 1, wherein the radiating plate is held so as not to face an end portion on the hot wind upstream side of the plate material and an end portion on a side close to a heat source of the heating furnace. The said radiating plate is stainless steel foil in which the oxide film was formed in the surface of thickness 100 micrometers or less, The heating method of the board | plate material in any one of Claims 1-3 characterized by the above-mentioned. A holding device for holding a plurality of plate members in parallel and holding a thin plate-like or foil-shaped copy plate between the plate members; And a heating furnace for circulating hot air to pass between the plate and the copy plate. As a holding device which holds the board | plate material heated in a heating furnace, Plate holder for holding a plurality of plate in parallel, And a copying plate holder for holding a thin plate-like or thin-shaped copy plate in parallel with the plate, between the plate and on both sides thereof. 7. The radiation plate holder according to claim 6, wherein the radiation plate holder comprises a plurality of struts standing up on both sides of the holding device, and a plurality of pressing plates for sandwiching the radiating plate therebetween with the struts. Retaining device. The holding device according to claim 7, wherein the copy plate holder holds the copy plate opposite to the bottom of the plate. The holding device according to any one of claims 6 to 8, wherein the radiation plate is a stainless steel foil having an oxide film formed on a surface of 100 µm or less in thickness.

Images