JP2007303728A - Furnace operation control method and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a furnace operation control method capable of setting a numerical value of appropriate parameter to a furnace for drying or burning a large panel more quickly in comparison with a conventional method. <P>SOLUTION: A model panel 6 coated with an evaporative material is set in an experiment unit 5 independent from a controlled furnace 1, an actual evaporation quantity change characteristic Gs of the evaporative material is calculated by actually measuring the evaporation quantity of the evaporative material, a calculatory time required for evaporation ts for evaporating the evaporative material of a heated panel 2 by a target evaporation quantity is calculated by using the actual evaporation quantity change characteristic Gs, and the numerical value of the parameter of the controlled furnace 1 is changed to make the time required for evaporation ts approaches a target time tr. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for controlling the operation of a furnace for drying or firing used for manufacturing a large display panel.

  In the manufacturing process of PDP panels (Plasma Display Panel), electrode materials, dielectric materials, barrier rib materials, etc. are printed on the panel, dried, exposed, developed, and fired. Thus, a target front panel and a back panel bonded to the front panel are manufactured.

  In the drying or firing process, the panel coated with the evaporable material is passed through an electric furnace for drying or firing, and various parameters of the drying or firing process are used so that the residual amount of the evaporable material approaches the target value. A certain furnace temperature, transfer speed, gas flow rate, etc. are set to appropriate values, and the operation of drying or firing a single panel is completed in a target time.

The configuration of the electric furnace is described in Patent Document 1 and the like, and the specific operation method of this electric furnace is described in Patent Document 2 and the like.
JP 2003-123651 A JP 2003-294371 A

  In the PDP panel, the display screen size is as large as 37 inches, 42 inches, 50 inches, 58 inches, and 65 inches, and the electric furnace tends to be larger. It is difficult to adjust the numerical values of various parameters in the drying or firing process to appropriate values in a short time.

  Specifically, it is necessary to change the numerical value of the parameter of the drying or baking process every time the evaporable material is changed, and the numerical value of the parameter required every time the evaporable material is changed. Currently, the setting work takes time to drive to an appropriate value.

  An object of this invention is to provide the furnace operation control method which can set the furnace which performs drying or baking of a large sized panel to the numerical value of an appropriate parameter quicker than before.

  In the furnace operation control method according to claim 1 of the present invention, when setting the numerical value of the parameter related to the performance of the controlled furnace for drying or firing the heat-treated panel, the evaporative material applied to the heat-treated panel is set. Set the model panel coated with the evaporable material with the same film thickness as the coating film thickness in an experimental unit different from the furnace to be controlled, set the temperature of the experimental unit to a specified temperature, A furnace operation control unit that calculates an actual evaporation amount change characteristic: Gs of the evaporable material by actually measuring the evaporation amount of the evaporable material, and controls the furnace to be controlled to have a predetermined temperature profile. The time required for evaporation: ts required to evaporate the evaporable material of the heat treatment panel by the target evaporation amount is calculated by the measured evaporation amount change characteristic: Gs of the evaporable material calculated based on the actual measurement. The calculated evaporated Duration: ts is target time: and changing the value of parameter of the control object furnace so as to approach the tr.

  In the furnace operation control method according to claim 2 of the present invention, when setting the numerical value of the parameter related to the performance of the controlled furnace for drying or firing the heat-treated panel, the evaporative material applied to the heat-treated panel is set. Set the model panel coated with the evaporable material with the same film thickness as the coating film thickness in an experimental unit different from the furnace to be controlled, set the temperature of the experimental unit to a specified temperature, The actual evaporation amount change characteristic: Gs of the evaporable material is calculated by actually measuring the evaporation amount of the evaporable material, and the actual evaporation amount change characteristic: Gs of the evaporable material calculated on the basis of this actual measurement is calculated. A characteristic of change in evaporation amount of the conductive material: an experimental constant necessary for converting Gr: C, and a furnace operation control unit for controlling the controlled furnace so as to have a predetermined temperature profile. The evaporation required time: ts required to evaporate the evaporable material of the processing panel by the target evaporation amount is calculated by correcting with the experimental constant: C so that the calculated evaporation required time: ts approaches the target time: tr. The numerical value of the parameter of the furnace to be controlled is changed.

  The furnace operation control method according to claim 3 of the present invention is the furnace operation control method according to claim 2, wherein the experimental constant: C is calculated for each of the evaporable material and the coating film thickness of the evaporable material, and the furnace operation control unit requires evaporation. When calculating the time: ts, the calculation is performed by correcting with the experimental constant: C corresponding to the evaporable material and the coating film thickness of the evaporable material.

  According to a fourth aspect of the present invention, in the furnace operation control method according to the first or second aspect, the numerical value of the parameter of the control target furnace is changed so that the calculated required evaporation time: ts approaches the target time: tr. This is characterized in that at least one of a temperature profile of the controlled furnace, a gas flow rate of gas supplied to and exhausted from the furnace, and a gas temperature is changed.

  A furnace operation control device according to claim 5 of the present invention is a furnace operation control device for a controlled furnace for drying or firing a heat-treated panel, and the type of evaporable material and the evaporability applied to the heat-treated panel. An experimental constant for correction corresponding to the coating film thickness of the material: a storage unit in which C is written, and the temperature of the furnace to be controlled are controlled based on a predetermined temperature profile, and evaporability applied to the panel to be heat-treated Evaporation required time: ts obtained by correcting the evaporation required time required to evaporate the evaporable material of the panel to be heat-treated by the target evaporation amount by the experimental constant: C read from the storage unit according to the coating thickness of the material. Is provided with a furnace operation control unit for changing numerical values of parameters related to the performance of the controlled furnace so as to approach the target time: tr.

  According to this configuration, the model panel is set in an experimental unit different from the furnace to be controlled, the amount of evaporation of the evaporable material applied to the model panel is measured in advance, and the change in measured amount of evaporation calculated by actual measurement Since the operation of the controlled furnace is controlled using the characteristics, the parameters of the controlled furnace can be set to appropriate numerical values of the parameters more quickly than in the past.

Hereinafter, the furnace operation control method of the present invention will be described based on specific embodiments.
FIG. 1 shows a furnace operation control apparatus for controlling the furnace 1 to be controlled. Here, a large panel such as a front panel for a PDP panel is the panel 2 to be heat-treated, and the panel 2 to be heat-treated is subjected to a drying or firing process by the controlled furnace 1.

  A predetermined inert gas such as air is supplied from the air supply pipe into the furnace to be controlled 1 so as not to blow directly to the heat-treated panel 2, and exhaust is performed through the exhaust pipe. Thereby, the evaporant inside the controlled furnace 1 is discharged to form a desired gas atmosphere, and the furnace temperature is adjusted by the gas temperature, gas flow rate, and heater temperature.

  The numerical value of the parameter for drying or firing processing of the controlled furnace 1 is set by the furnace operation control unit 3 as the value of the control parameter for drying or firing operation. Here, the numerical values of the control parameters for the drying or firing operation are the components of the evaporable material applied to the heat-treated panel 2, the film thickness of the applied evaporable material, and the target film thickness. Target time required for the process: tr, the temperature profile of the heat-treated panel 2 heated in the controlled furnace 1, the gas flow rate of the controlled furnace 1, and the like. The evaporable material contains, for example, an organic solvent such as ethylene glycol or terpineol, or an organic binder such as ethyl cellulose.

  A storage unit 4 is connected to the furnace operation control unit 3. An experimental unit 5 is electrically connected to the storage unit 4. In this storage unit 4, data is written in advance in the files F 1, F 2,..., Fn in accordance with the evaporable material and the coating film thickness of the evaporable material, and specified by the furnace operation control unit 3. The data can be read from the files F1, F2,..., Fn in correspondence with the evaporated material and the coating film thickness of the evaporated material.

  The experimental unit 5 is a furnace that is smaller than the furnace 1 to be controlled. Here, the experimental unit 5 contains a model panel 6 that is smaller than the panel 2 to be heat treated and is dried or fired. Is applied with an evaporable material having the same component as the evaporable material applied to the panel 2 to be heat-treated. The experimental unit 5 is configured so that the gas flow rate is the same as or substantially the same as that of the controlled furnace 1 and temperature control is performed so as to raise the temperature to the specified temperature, and the change characteristics of the evaporation amount of the evaporable material with respect to the elapsed time can be measured. ing.

FIG. 3 shows a specific example of the experimental unit 5.
The experimental unit 5 includes an experimental unit body 7 and a weighing device 8 that measures the weight. The experimental unit body 7 includes a lower heater 9 and an upper heater 10, and a cylindrical partition wall 11 whose upper and lower portions are closed by the lower heater 9 and the upper heater 10.

  The model panel 6 in which the coating thickness of the evaporable material 12 is a specified thickness is placed on the lower heater 9 and is heated by the lower heater 9 and the upper heater 10 according to a predetermined temperature profile. A constant amount of air flow 13 is blown from the outside to the inside of the partition wall 11, and the evaporating material 12 applied to the model panel 6 is evaporated by the above-described temperature raising operation, and the solvent gas 14 is separated from the partition wall 11. 11 is discharged from the inside to the outside. The weighing device 8 detects a weight change in which the evaporable material 12 applied to the model panel 6 evaporates and the weight is reduced. From the change in the weight of the weighing device 8, it is read as an actual measured value (evaporation amount change characteristic (measured value) Gs described later) of the occasional film thickness of the evaporable material 12 remaining on the model panel 6.

  In the above-described measurement in the experimental unit 5, the weight change is measured by measuring several kinds of model panels 6 with different coating film thicknesses for each kind of the evaporable material 12, and the evaporation remaining in the model panel 6 is measured. This is read as an actual measurement value of the thickness of the material 12.

Data are written in the files F1, F2,..., Fn of the storage unit 4 as follows.
At the time of this writing, the calculated evaporation amount change characteristic (theoretical value) of the evaporable material calculated based on the actually measured temperature change characteristic of the model panel 6 is calculated by the following equation according to Stephan's law.

_{Ga = (D T / R ·} T) · (P S -P ∞ / δ)
Here Ga evaporation of vaporizable material, D _T is the diffusion coefficient when the solvent vapor spreads into the air, R represents gas constant, T is temperature, P _S is the saturation vapor pressure, P _∞ vapor partial pressure, [delta] Indicates the boundary layer thickness. Each value in the equation is calculated using a well-known equation. For example, the diffusion coefficient D _T is calculated by the following Gillian equation.

D _T = (0.0043T ^3/2 / P (V ^1/3 + Vair ^1/3 ) ² ·
√ ((1 / M) + (1 / M _air ))
Here, P is total pressure, M and M _air are molecular weights, V and Vair are boiling molecular weights, and T is temperature.

  FIG. 2 shows the calculated evaporation amount variation characteristic (theoretical value) Gr and the evaporation amount variation characteristic when the flow rate of the inert gas is the same as or substantially the same as that of the controlled furnace 1 and the temperature of the experimental unit 5 is increased with a predetermined temperature profile. (Actually measured value) Gs is shown, and an experimental constant: C is calculated to convert the calculated evaporation amount change characteristic (theoretical value) Gr into the evaporation amount change characteristic (actually measured value) Gs. Is recorded in the storage unit 4 in correspondence with the coating film thickness of the evaporable material. Hereinafter, the coating constant of the evaporable material at the start with the same evaporable material is changed to another value, and the experimental constant: C in that case is calculated in the same manner. Further, the experimental constant: C is calculated by changing the evaporable material.

FIG. 4 is a flowchart showing how to obtain the experimental constant C.
Input data is physical property data, coating conditions of drying conditions and shape data: d, and physical data are boiling molecular volume, molecular weight, compounding ratio (weight ratio, volume ratio), vapor pressure of solvent of evaporable material It is a curve. The drying or firing conditions are the wind speed on the model panel 6 and the temperature data of the model panel 6.

At steps S1 and S2, to calculate the _{Ga = S · (D T /} R · T) · (P S -P ∞ / δ), is seeking a theoretical value of the solvent evaporation in the coating film. Here, S is an area ratio.

  In step S3, the solvent evaporation amount at a specific time obtained from the theoretical value obtained in step S2 and the weight change measured in the experimental unit 5 using the model panel 6 as described above in steps S4 and S5. Compare with experimental values. In step S6, step S7, and step S8, an experimental constant: C is determined so that the actual measurement value overlaps the experimental value and the theoretical value.

  The experimental constant C obtained in this way is, for example, the experimental constant C for each evaporative material coating film thickness at the start of each evaporable material, and the files F1, F2,. , Fn.

  In addition, since drying starts from the surface of the film, a thick film having a thickness of 100 microns or more is more stretched on the surface of the coating film than a thin film having a coating thickness of several microns to several tens of microns. Since a phenomenon that inhibits evaporation of the solvent in the film to the outside occurs, the experimental constant: C is a function of the coating film thickness: d.

  When drying or firing the panel 2 to be heat-treated in the controlled furnace 1, the furnace operation control unit 3 gives the type of evaporable material with various parameters as operating conditions, the coating thickness of the evaporable material, the temperature profile, and the application. When a target time: tr or the like for drying the evaporable material that has been input is input, the furnace operation control unit 3 refers to the storage unit 4 and executes a simulation.

  Specifically, the furnace operation control unit 3 designates the type of evaporable material and the coating thickness of the evaporable material at the start from the files F1, F2,. Read the experimental constant C corresponding to. Although it is preferable to read the coating film thickness of the evaporable material from the same file as that of the furnace to be controlled, it can be used by reading from the file having the coating film thickness of the evaporable material substantially the same.

The furnace operation control unit 3 shows the calculated evaporation amount change characteristic (theoretical value) of the evaporable material over time when the panel 2 to which the specified evaporable material is applied is operated with the specified temperature profile. The calculated evaporation amount change characteristic is dried or baked using the evaporation amount change characteristic corrected by the experimental constant C read out from the storage unit 4. Required evaporation time: ts is obtained. As a result of simulation,
ts = tr or ts ≒ tr
In this case, the furnace operation control unit 3 operates the controlled object furnace 1 under the simulation conditions at that time. When the error between ts and tr is large, the temperature profile, gas flow rate, and gas temperature as parameters of the controlled furnace are adjusted so that the calculated evaporation time: ts approaches the target time: tr. Change at least one of them and repeat the simulation. When the panel 2 to be heat-treated is transferred in the loading / unloading direction inside the controlled furnace 1, the simulation is repeated with at least one change including this.

  It has been described that when the simulation result is ts = tr or ts≈tr, the furnace operation control unit 3 executes the operation of the controlled furnace 1 under the simulation conditions at that time. When the furnace operation control unit 3 automatically reconfirms that the solvent concentration in the furnace of the controlled target furnace 1 during operation is not a preset explosion concentration or a concentration close thereto, and clears this condition Only the drying operation of the controlled furnace 1 based on the simulation result is started. If it is found that the explosion concentration is set at or near the preset concentration, the simulation routine is repeated until a safe condition is found again by returning to the simulation routine. For this reason, the furnace operation control unit 3 is set in advance with weighting for designating the order of changing the parameters in one or a plurality of combinations.

  In this way, the furnace operation control unit 3 refers to the storage unit 4 and corrects the calculated evaporation change characteristic with the experimental constant: C, and automatically executes the simulation so that ts approaches tr. Thus, since the operation of the controlled object furnace 1 is executed, the controlled object furnace 1 can be operated quickly with appropriate parameters as compared with the conventional case, and an improvement in the yield of the heat-treated panel 2 can be expected.

Moreover, it is particularly effective in a drying line that switches and produces a variety of heat-treated panels 2 having different evaporable materials.
In the above embodiment, the case where the experimental data is corrected based on the experimental constant for correction C and the parameters of the controlled furnace 1 are set is described as an example. Even when the numerical value of the parameter of the controlled furnace is set so that the time required for evaporation: ts approaches the target time: tr without correcting the data, the numerical value of the parameter of the controlled furnace is set to be faster than before. It can approach the appropriate value and contribute to the realization of a high yield.

  INDUSTRIAL APPLICABILITY The present invention can contribute to realizing various large panel drying or firing processes quickly and with a high yield.

The block diagram of the furnace operation control apparatus used for implementation of the furnace operation control method of this invention Relationship diagram between calculated evaporation amount change characteristic (theoretical value) Gr and evaporation amount change characteristic (actual value) Gs in the same embodiment Configuration diagram of the experimental unit in the same embodiment Flowchart for determining experimental constant: C in the same embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Control object furnace 2 Panel to be heat-treated 3 Furnace operation control part 4 Memory | storage part 5 Experimental unit 6 Model panel Gs Measured evaporation amount change characteristic Gr Calculated evaporation amount change characteristic C Experimental constant ts Evaporation time tr Target time

Claims (5)

When setting the numerical values of the parameters related to the performance of the controlled furnace that dries or fires the panel to be heat-treated,
A model panel coated with the evaporable material with the same film thickness as the evaporable material applied to the panel to be heat-treated is set in an experimental unit different from the controlled furnace,
By setting the temperature of the experimental unit to a specified temperature and measuring the amount of evaporation of the evaporable material with respect to the elapsed time, the measured evaporation amount change characteristic of the evaporable material: Gs is calculated,
Based on the actual measurement, the furnace operation control unit that controls the furnace to be controlled to have a predetermined temperature profile needs the evaporation time: ts required to evaporate the evaporable material of the heat-treated panel by the target evaporation amount. The calculated actual evaporation amount change characteristic of the evaporable material: calculated by Gs,
A furnace operation control method in which the numerical value of the parameter of the controlled furnace is changed so that the calculated required evaporation time: ts approaches the target time: tr. When setting the numerical values of the parameters related to the performance of the controlled furnace that dries or fires the panel to be heat-treated,
A model panel coated with the evaporable material with the same film thickness as the evaporable material applied to the panel to be heat-treated is set in an experimental unit different from the controlled furnace,
By setting the temperature of the experimental unit to a specified temperature and measuring the amount of evaporation of the evaporable material with respect to the elapsed time, the measured evaporation amount change characteristic of the evaporable material: Gs is calculated,
Calculate the experimental constant: C necessary to convert the calculated evaporation amount change characteristic: Gr of the evaporable material into the measured evaporation amount change characteristic: Gs of the evaporable material calculated based on the actual measurement.
The furnace operation control unit that controls the furnace to be controlled so as to have a predetermined temperature profile, the evaporation required time: ts required for evaporating the evaporable material of the heat-treated panel by the target evaporation amount is the experimental constant: C. Corrected and calculated,
A furnace operation control method for changing the numerical values of the parameters of the furnace to be controlled so that the calculated required evaporation time: ts approaches the target time: tr. Calculate the experimental constant: C for each evaporable material and the coating thickness of the evaporable material,
3. The furnace operation control method according to claim 2, wherein when the furnace operation control unit calculates the evaporation required time: ts, the calculation is performed by correcting with the experimental constant: C corresponding to the evaporation material and the coating film thickness of the evaporation material. . Changing the numerical value of the parameter of the controlled furnace so that the calculated evaporation time: ts approaches the target time: tr,
The furnace operation control method according to claim 1 or 2, wherein at least one of a temperature profile of a controlled furnace, a gas flow rate of gas supplied to and exhausted from the furnace, and a gas temperature is changed. A furnace operation control device for a controlled furnace for drying or firing a heat-treated panel,
A storage unit in which C is written in accordance with an experimental constant for correction corresponding to the type of the evaporable material and the coating thickness of the evaporable material applied to the panel to be heat-treated;
The temperature of the furnace to be controlled is controlled based on a predetermined temperature profile, and the heat treatment is performed by the experimental constant: C read from the storage unit according to the coating thickness of the evaporable material applied to the heat treated panel. The numerical value of the parameter related to the performance of the controlled furnace is changed so that the time required for evaporation: ts corrected for the time required for evaporation to evaporate the evaporable material of the panel by the target evaporation amount approaches the target time: tr A furnace operation control device provided with a furnace operation control unit.

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