JPH0527126B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an interference-compatible automatic pattern switching temperature control device for a heat treatment furnace having a plurality of zones that thermally interfere with each other. More specifically, the present invention is a heat treatment furnace in which the heat treatment is carried out by moving the treated product from one end of the furnace to the other end using a conveyor or the like while maintaining the longitudinal heat distribution in a constant pattern, and the workpiece is taken out from the other end of the furnace. The present invention relates to an interference-compatible pattern automatic switching temperature control device that automatically switches the temperature of a tunnel furnace for each zone in response to changes in the type of product to be processed.

Conventional technology In tunnel-type heating furnaces such as conveyor furnaces and pusher furnaces, the temperature distribution pattern in the furnace is set to an appropriate temperature distribution that matches the processed product to be heated, and the processed product is fed at an appropriate conveyance speed. Perform the necessary heat treatment.

FIG. 2 shows a prior art approach to obtaining the desired temperature distribution in these furnaces. In the figure, a furnace 1 is divided into a plurality of zones Z1-Zn, and the temperature of a heating element 2 or a heating section provided in each zone is determined by a temperature detection element 4 such as a thermocouple using a controller 28A-28N. is input. Controller 28
A-28N generates the operation signal 5 calculated by the calculator 27A so that the input value matches the temperature set by the built-in setting element 27. This operation signal 5 is applied to an operation section 3 composed of, for example, a thyristor or an electromagnetic switch, and is used to control the temperature of each zone Z1-Zn by adjusting the energy supply from the power supply or other energy source 2A.

As a result, a temperature distribution pattern shown by curve Pa or Pb is generated in the entire furnace. The processed product 6 is carried in from one end of the furnace 1 and taken out from the other end as shown by arrow 30, and subjected to the required heat treatment.

In this case, in order to check whether the desired temperature distribution pattern has been obtained in the furnace by the heating element 2,
That is, in order to check the furnace temperature and temperature distribution, a movable furnace temperature detector 31 is used in the illustrated example. The furnace temperature detector 31 moves inside the furnace 1 and continuously inputs the furnace temperature to the recorder 32, and the recorder 32 records and displays the furnace temperature distribution.

In the conventional method, when the temperature and temperature distribution recorded on the recorder 32 are not desired, the setting element 27 in the controller 28A-28N of the desired zone
It is necessary to manually change the set value of , wait for the temperature inside the furnace 1 to stabilize, and then measure the temperature distribution again. However, although the furnace 1 is divided into zones, the adjacent zones are not completely separate and independent, and it is essential that the processed product 6 passes through the furnace. The temperature inside, ie, the part through which the processed product 6 passes, is different. For this reason, even if the temperature setting value for a specific zone is changed to a desired value independently, the desired temperature distribution is not necessarily obtained due to the influence of zones adjacent on both sides of the zone.

In reality, when changing the above-mentioned temperature set value for each heating element 2, after changing the first set value, wait until the inside of the furnace 1 is thermally balanced and then move the furnace temperature detector 31. The desired temperature distribution pattern can be achieved by checking the furnace temperature and temperature distribution pattern, readjusting the set value according to the difference from the desired value, and then performing the operation of checking the furnace temperature distribution pattern several times or more. The reality is what we were getting.

Therefore, there is a drawback that it takes a considerable amount of time and effort to obtain a desired temperature distribution pattern within the furnace.
Particularly in the recent era of high-mix, low-volume production, temperature distribution patterns are diversifying, and the above adjustment procedure has to be performed frequently.

Furthermore, after finding stable values that will provide the desired temperature distribution pattern for a certain product 6 and setting these in the controllers 28A-28N, the above-mentioned repeated adjustments are made to a large number of set values each time the type of product 6 changes. Not only is it extremely complicated, but it also requires considerable experience and skill.

Problems to be Solved by the Invention ``Therefore, the problems to be solved by the present invention are how to deal with thermal interference between adjacent zones when switching the furnace temperature in a tunnel furnace, and how to change the temperature distribution pattern in the furnace. Automation, especially automation that is synchronized with the progress of products being processed in the furnace, and speeding up temperature distribution pattern switching.

Means for Solving the Problems The means for solving the above problems will be explained in terms of its principle and configuration.

[Principle] FIG. 1 shows a block diagram of a schematic configuration of an embodiment of the present invention and a temperature distribution pattern in a tunnel furnace. In the figure, a tunnel furnace 1 has a plurality of zones Z1-Zn, and the heating elements 2 in each zone are controlled by a digital temperature control device 15 via operating units _31-3n . A movable furnace temperature detector 31 moves within the furnace to measure the furnace temperature distribution pattern. The furnace temperature detector 31 may not be movable but may be attached to each zone. The figure also shows three types of patterns P1, P2, P3 as examples of temperature distribution patterns for different types of processed products 6.
shows.

In the apparatus of the present invention, the set value of the temperature setting element 40 (FIG. 5) of the temperature control device 15, which is set for the heating part temperature of each zone Z1-Zn, is set to the furnace internal temperature of the required temperature distribution pattern (hereinafter referred to as , "internal temperature"
That's what it means. ) is set to a value that is likely to give, and the control operation is started. After the internal temperature of each zone Z1-Zn has stabilized, the furnace temperature detector 31 is connected to the zone at one end of the furnace 1.
It is moved from Z1 to zone Zn at the other end, and the internal temperature of each zone is sequentially measured and stored in the storage device 20.

Normally, the processed product 6 passes through the furnace as shown by the arrow 30, so the temperature of the heating section near the heating element 2 and the processed product 6 are controlled from the outside of the furnace 1.
This is different from the temperature inside the furnace through which it passes. To distinguish between these temperatures, in the following description furnace 1
The temperature of the heating section near the heating element 2, which is controlled from the outside, is called the "external temperature" x, and the temperature inside the furnace through which the processed product 6 passes is called the "internal temperature" y, as described above. For the sake of simplicity, it is assumed that the external temperature x matches the set value set in the temperature setting element 40 of the temperature control device 15 after the control is performed well and stability is reached.

Internal temperature from external temperature x _i in each zone Zi
The transfer gain to y _i is g _ii , and the external temperature of zone Zj is
The transfer gain from x _j to the internal temperature y _i of zone Zi is g _ij
Then, the relationship between external temperature x and internal temperature y is given by the following equation.

y ₁ = g ₁₁ x ₁ + g ₁₂ x ₂ + g ₁₃ x ₃ ⁺ … ⁺ g _1o x _o y ₂ = g ₂₁ x ₁ + g ₂₂ x ₂ + g ₂₃ x ₃ ⁺ … ⁺ g _2o x _o 〓 y _o = g _o1 x ₁ + g _o2 x ₂ + g _o3 x ₃ ⁺ … ⁺ g _oo x _o …(1) If this is expressed as a determinant, it becomes as follows.

y ₁ y ₂ 〓 y _o =g ₁₁ g ₁₂ g ₁₃ …g _1o g ₂₁ g ₂₂ g ₂₃ …g _2o 〓 〓 g _o1 g _o2 g _o3 …g _oo x ₁ x ₂ 〓 x _o …(2) Here , internal temperatures y ₁ , y ₂ ,...y _o are temperatures measured by the furnace temperature detector 31, and external temperatures x ₁ ,
x ₂ . _. .

Since there are n transfer gains g for each zone, it is necessary to perform measurements n times to obtain all g.
Even if the measurement is performed while the external temperature x is kept constant, the same equation will be obtained, which is meaningless, and it is necessary to reset the external temperature x to a different arbitrary value and then perform the measurement. The measured value obtained by measuring n times in this way satisfies the following equation. However, y _ij is the measured value of the internal temperature of the i-th zone Zi measured j-th time, and x _ij is the external temperature of the i-th zone Zi set or measured j-th time.

y ₁₁ y ₁₂ y ₁₃ …y _1o y ₂₁ y ₂₂ y ₂₃ …y _2o 〓 〓 y _o1 y _o2 y _o3 …y _oo =g ₁₁ g ₁₂ g ₁₃ …g _1o g ₂₁ g ₂₂ g ₂₃ …g _2o 〓 〓 g _o1 g _o2 g _o3 …g _oo x ₁₁ x ₁₂ x ₁₃ …x _1o x ₂₁ x ₂₂ x ₂₃ …x _2o 〓 〓 x _o1 x _o2 x _o3 …x _oo (3) Solving equation (3) for g , the transfer gains g between the outside and inside of all zones and between zones are obtained. Once all the transfer gains g are obtained, any external temperature distribution |x ₁ ′x ₂ ′…x ₃ ′|′ that gives rise to an arbitrary internal temperature distribution |y ₁ ′y ₂ ′…y ₃ ′| 3) Determined by calculation from formula.

The present invention achieves the required temperature distribution pattern inside the furnace using the outside temperature distribution |x ₁ ′x ₂ ′...x ₃ ′|′ determined by the above measurements and calculations. When the number of zones is small, equation (3) can be used as is, but in reality, furnaces with more than 10 zones are not rare, so using equation (3) directly would require a large number of measurements and the calculations would be extremely complicated. Become.

In practice, the following simplified method can be used. i-th zone Zi and its adjacent zone Zi−
1 and Zi+1 are enlarged, and FIG. 4 is an explanatory diagram of the self-transfer gain g _ii and mutual transfer gain g _ij , the transfer gains g _i,i+1 , etc. between directly adjacent zones are shown in FIG. is significant, but it is assumed that the transfer gains g _{i-1, i+1,} etc. between zones that are not directly adjacent are negligibly small. Furthermore, it is assumed that any transfer gains g between zones further apart than shown in FIG. 3 are negligible.

Under this assumption, equations (1) and (2) above can be rewritten as follows.

y ₁ = g ₁₁ x ₁ + g ₁₂ x ₂ y ₂ = g ₂₁ x ₁ + g ₂₂ x ₂ + g ₂₃ x ₃ y ₃ = g ₃₂ x ₂ + g ₃₃ x ₃ + g ₃₄ x ₄ 〓 y = g _o,o-1 x _o-1 +g _oo x _o (4) Therefore, y ₁ y ₂ y ₃ 〓 y _o =g ₁₁ g ₂₁ 0 〓 0g ₁₂ g ₂₂ g ₃₂・0 g ₂₃ g ₃₃・・ 0 g ₃₄ 0・ ・0 g _o・ ・・_o-1 0 0 0 〓 g _oo x ₁ x ₂ x ₃ 〓 x _o (5) y _o 0...0g _o,o-1 g _oo x _o (5) Calculated using equation (5) The number of power transmission gains is (3n-2) in total since there is no one for the outer adjacent portions of the zones at both ends. Therefore, in order to obtain only the necessary transfer gain under the above assumption, it is sufficient to move the furnace temperature detector 31 within the furnace 1 three times and measure it, thereby simplifying the measurement and calculation. The internal temperature distribution y determined by three measurements is expressed by the following equation.

y ₁₁ y ₁₂ y ₁₃ y ₂₁ y ₂₂ y ₂₃ y ₃₁ y ₃₂ y ₃₃ 〓 y _o1 y _o2 y _o3 =g ₁₁ g ₁₂ 0 〓 0g ₁₂ g ₂₂ g ₃₂ 00 g ₂₃ g ₃₃ 0・・・・ 0・・・ g ₃₄ ⁰・ ・・0・・ ・・・ g _o,o-1 0 0x ₁₁ x ₁₂ x ₁₃ x ₂₁ x ₂₂ x ₂₃ x ₃₁ x ₃₂ x ₃₃ (6) From equation (6), the i-th 3 of the internal temperature y _i of the th zone Zi
If we extract the part related to the measured value of times, we can write it as follows.

y _i1 y _i2 y _i3 = x _i-1,1 x _i1 x _i+1,1 x _i-1,2 x _i2 x _i+1,2 x _i-1,3 x _i3 x _i+1,3 g _i,i-1 g _i,i g _i,i+1 …(7) If the external temperature matrix in equation (7) is A, then A≡x _i-1,1 x _i1 x _i+1,1 x _i-1,2 x _i2 x _i+1,2 x _i-1,3 x _i3 x _i+1,3The transfer gain for this zone Zi is given by the following equation.

g _i,i-1 =1/Ay _i1 x _i1 x _i+1,1 y _i2 x _i2 x _i+1,2 y _i3 x _i3 x _i+1,3 …(8) g _i,i =1/ Ax _i-1,1 y _i1 x _i+1,1 x _i-1,2 y _i2 x _i+1,2 x _i-1,3 y _i3 x _i+1,3 …(9) g _{i,i +1} = 1/Ax _i-1,1 x _i1 y _i1 x _i-1,2 x _i2 y _i2 x _i-1,3 x _i3 y _i3 …(10) (8), (9), (10) Calculate the formula for all zones Z1−Zn of furnace 1
By doing this, the required transfer gain g
are all found. According to the method of equations (6) to (10),
Even if the number of zones increases, by setting different external temperatures three times and measuring the internal temperature by moving the furnace temperature detector 31 a total of three times, once for each set value, the transfer gain of equation (6) can be obtained. All g can be found.

The transfer gain g obtained in this way is
5 in the storage device 20. The external temperature distribution required to give the required internal temperature matrix |y _{1 ′} y _{2 ′} …y ₃ ′|′ is _the transfer gain g
The following equation regarding .

y' ₁ y' ₂ y' ₃ 〓 y' _o =g ₁₁ g ₂₁ 0 〓 0g ₁₂ g ₂₂ g ₃₂・0 g ₂₃ g ₃₃・・ ・ 0・・ g ₃₄ 0・ 0g _o,o-1 0 0 0 〓 g _oo x' ₁ x' ₂ x' ₃ 〓 x' _o (11) Since equation (11) is a step-like equation, it gives the required temperature distribution pattern, that is, the above internal temperature matrix | y ₁ ′ The external temperature distribution |x _{1 ′} x ₂ ′...x ₃ ′|′ required to give y 2 ′...y ₃ ′|′ can be easily found sequentially by the process of elimination.

Therefore, pattern switching control of the furnace temperature that takes into account the interference between zones can be achieved by controlling the heating section temperature, that is, the external temperature, using equations (6) or (8)-(11). .

In order to synchronize the switching of the temperature distribution pattern with the change in the type of the processed product 6 progressing in the furnace 1, the following can be done, for example. That is, the quantity (hereinafter referred to as "planned number of processing") of the type of products 6 to be processed in a specific temperature distribution pattern _is set in the product setting element 41 (FIG. 5), and the number of products 6 to be processed in the furnace 1 is Counting means 45 (fifth
), detect the coincidence between the count value of the counting means 45 and the scheduled processing number U _s , and switch the temperature distribution pattern in synchronization with this coincidence detection.

[Configuration] Referring to FIG. 5, the interference compatible pattern automatic switching type temperature control device 15 according to the present invention has a plurality of zones Z1- in which the heating section temperature detection elements 4 are provided.
In order to control the temperature of the furnace 1 which has an internal temperature detector 31 for detecting Zn and the internal temperature of each zone, the external temperature set value series x _is or the different values for each zone for a specific temperature distribution pattern P _s is determined. Setting value column
It has a temperature setting element 40 in which x _ir is selectively set, and a processed product setting element 41 in which the scheduled number of processed products 6 U _s is set.

The type S of the product 6 to be processed, the number U _s to be processed by product type for the plurality of products 6, the plurality of temperature distribution patterns P _s to be controlled, and the set value series of different values.
A storage device 20 is provided for storing x _ir and the internal temperature y _ir of each zone detected by the furnace temperature detector 31. Further, calculation means for calculating the heat transfer gain matrix g _ij from the above-mentioned equation (3) or (6) from the setting value string x _ir of different values and the internal temperature y _ir of each zone for the setting value string. 8
Set 0.

The calculation means 80 uses the transfer gain matrix obtained in this way to calculate the set value sequence x _is that should give the temperature distribution pattern P _is from the temperature distribution pattern and the heat transfer matrix, and calculates the set value sequence x is that should give the temperature distribution pattern P is from the temperature distribution pattern and the heat transfer matrix. It also has the function of storing data.

A setting means 60 is provided for selectively setting the set value series stored in the storage device 20 in the temperature setting element 40 according to the operation of the furnace 1. The setting means 60 also reads out the scheduled number of processing items U _s of the processing items 6 from the storage device 20 and sets the processing item setting element 41 .
It also has a function to set. Processed product 6 type S
It is not necessary to provide a special signal for type S, since it can be distinguished based on the number of scheduled processes. However, if the type signal S is provided independently, it can also be set in the processed product setting element 41.

For example, furnace 1 has zones Z1, Z2, Z3, Z4,
In the case of having five _{zones of} Z5 _{, as shown} in FIG _.
, and the temperature pattern P ₂ has a total of five portions P2 ₁ , P2 ₂ , P2 ₃ , P2 ₄ , P2 ₅ for each zone. A workpiece detector 7 provides a workpiece signal 8 for each workpiece 6 to the temperature control device 15 in synchronization with the progress of the workpiece 6 through the furnace 1 . A counting means 45 counts this processed product signal 8. The count value of the counting means 45 for the products 6 to be processed in a certain furnace temperature distribution pattern, for example P ₁ , matches the planned number of products to be processed according to the furnace temperature distribution pattern stored in the storage device 20. At this time, the setting means 60 stores the external temperature setting value sequence x _i2 corresponding to the next subsequent furnace temperature distribution pattern P ₂ from the storage device 20 in synchronization with the progress of the processed product 6 in the furnace 1. Each zone is read out to the element 40.

The heating element 2 of each zone is adjusted according to the difference between the detected temperature detected by the temperature detection element 4 of each zone Z1 to Zn and the external temperature set value x _is read to the temperature setting element 40 for the zone. Control means 50 for operation are included in the temperature control device 15 .

For the furnace 1 where the time constant of temperature change is large, an appropriate number of dummy bodies 14 (Fig. 7) are inserted between type A and type B of the processed products 6, which are treated at different temperatures, so as to match the time constant. After passing through the dummy body 14 for an amount of time, it is also possible to introduce the processed product 6 for a new processing temperature into the furnace 1. When using the dummy body 14, a selection driving means 7 for selectively driving the processed product line 11 (FIG. 7) and the dummy line 12
0 may be included in the temperature control device 15.

Function The function will be explained with reference to FIGS. 5 and 6.
When the operation starts, first, in step 301, the count value r is set to 1, in step 302, a sequence of appropriate temperature setting values x _i1 is set in the temperature setting element 40 and stored in the storage device 20, and in step 303, the sequence of temperature setting values Start control and measurement of internal temperature. In step 304, it is detected whether or not the internal temperature has become stable. If it is stable, the internal temperature y _i1 is stored in the storage device 20 in step 305. Under the monitoring of the count value r by the logic step 306, the count value r is determined in step 307.
is changed, and the set value of the temperature setting element 40 is changed in step 308, and a loop operation is performed in which the above control, measurement, and storage are repeated.
Perform internal temperature measurement and storage.

Next, in step 309, the count value r is reset, and the process proceeds to step 310 for calculating and storing the transfer gain g using equations (8) to (10). In step 311, the internal temperature matrix for the required temperature distribution pattern Pis is input to the calculation means 80 as the y' _i matrix of equation (11). In step 312, calculate the external temperature using equation (11).
A set temperature _x is corresponding to x' _i is calculated, and in step 313 these set temperatures are stored in the storage device 20 and set in the temperature setting element 40.

In step 314, control by the adjusting means 50;
That is, the operation signal 5 is generated to eliminate the difference between the output of the temperature detection element 4 and the set value of the temperature setting element 40, and control is performed using the operation signal 5. At the same time, the internal temperature is measured by the furnace temperature detector 31.

Once the stability of the furnace temperature is confirmed in step 315,
In step 316, the furnace temperature y _i is measured and stored,
The difference Δy _i between the required temperature distribution pattern and the measured furnace temperature is calculated by the temperature comparison means 46 in step 317. When it is detected in step 318 that this temperature difference Δy _i is larger than a certain value K, the correction amount Δx _i of the external temperature is calculated in step 319 using equation (11), and in step 320, the correction number is It is added algebraically to the setting value of the setting element 40. Steps using the set values corrected in this way
The control operation of 314 is repeated until the temperature difference Δy _i becomes equal to or less than a certain value K. According to the present invention, since the correction amount is calculated using the transfer gain, the temperature in the furnace can be quickly converged.

In the example of FIG. 6, once the set value of the external temperature for a specific temperature distribution pattern is determined, step 321
After storing the set value, external temperature set values for other temperature distribution patterns are calculated.

When step 322 detects completion of the external temperature setpoint calculation, control proceeds to control the heat treatment of the processed product.

In an actual furnace, after the temperature setting value is changed, a certain amount of time delay is inevitable until the temperature inside the furnace reaches the new setting value and stable control is performed. Since it is inconvenient to carry the processed product into the furnace during this time delay period, for example, a dummy body 14 is used during the temperature transition period as shown in FIG. 7. In the case of the same figure, the dummy body is fed until the temperature of the zone through which the products from the preceding lot have passed reaches the temperature for the products to be processed from the next subsequent lot. is sent to that zone.

In the control, first, in step 323, the external temperature set value sequence x _is previously calculated for the heat treatment temperature distribution pattern of the processed product 6 of the specific type S is read out from the storage device 20 and set in the temperature setting element 40,
Further, the scheduled processing number U _s of the processing product type S is read from the storage device 20 into the processing product setting element 41 .
At this time, the count value _Vc of the processed product signal 8 in the counting means 45 is reset to zero.

In response to the input of the processed product signal 8 from the processed product detector 7, the count value V _c is increased by 1 at step 324. In the illustrated example, the type S is determined in step 325, and if it is a dummy body, the dummy line side D of the selection drive means 70 is driven. In step 326,
It is determined whether or not the count value V _c is less than the number U _s scheduled to be processed by the processing item setting element 41 .

If the number of items scheduled to be processed has not been completed, the product line side W of the selection drive means 70 is driven, and at step 327 it is determined whether the type S of the product 6 to be processed has changed for each zone Zi. be done. If there is no change in the type S of the processed product 6 in all zones Z1-Zn, the same control and measurement as in step 303 is performed in step B328.

The situation of this change in the processed product type S will be explained with reference to FIGS. 5, 6, and 7. In the graph a of FIG. 7, it is assumed that the temperature distribution pattern P ₁ is suitable for the type A processed product 6, and the temperature distribution pattern P ₂ is suitable for the type B processed product 6.

For a certain temperature distribution pattern, in steps 326 and 327, the counted value of the processed product signal 8 by the counting means 45 is less than or equal to the planned number of processed products 6 to be processed according to the temperature distribution pattern stored in the storage device 20. In addition, if it is determined that there is no change in the type of product to be processed as the product progresses in any of zones Z1 to Z5, the setting means 60 does not operate at all, and the selection drive means 70 also switches the selection. Instead, the adjusting means 50 operates based on the external temperature set value series already set in the temperature setting element 40 and the temperature detected by the temperature sensing element 4, as shown in step 328 in FIG.

On the other hand, in steps 326 and 330, it is recognized that the count value V _c of the processed product signal 8 by the counting means 45 matches the scheduled processing number U _s set in the processed product setting element 41, and furthermore, there is a subsequent processed product 6. In this case, as shown in step 323, the setting means 6
0 is the external temperature set value string corresponding to the temperature distribution pattern P _s+1 that follows the temperature distribution pattern in question.
x _{i (s+1)} is read from the storage device 20 to the temperature setting element 40. At the same time, the planned processing number of subsequent processing products 6 is U _s+1
reading and resetting of the count value _Vc of the counting means 45 are also carried out.

For example, if the counting means 45 has finished counting the planned number of dummy bodies 14 in FIG. In _step 329, the external setpoint value _x12 corresponding to the temperature _P12 of the portion of zone Z1 of zone Z1 is read out from the storage device 20 to the setting element 40. In this way, the adjustment means 50 uses the newly read setting value to the setting element 40.
is activated.

A case will be explained in which it is determined in step 326 that the processing of the planned number of products has not been completed, and furthermore, a change in the type of products to be processed in one of the zones is recognized in step 327. The time point when the first item in the six rows of processed items of type B shown in Fig. 7 reaches zone Z2 is
For example, the time point when the counting means 45 counts that a certain number, for example m, of type B processed products 6 have passed through the processed product detector 7 after the first processed product 6 has been detected by the processed product detector 7 is set as the point in time. Can be detected indirectly. This number m is determined by the dimensions of zone Z1 and each processed product 6.

At the time of detection in this way, zone Z2
The only difference is that the incoming processed product and the outgoing processed product are different. In other words, if the type B processed product 6 enters and the dummy body 14 is sent out, then the temperature distribution pattern P ₂ for the type B processed product 6 corresponds to the part corresponding to zone Z2.
External temperature setpoint x ₂₂ corresponding to P ₂₂ is step 329
The setting value is read out from the storage device 20 to the setting element 40, and the part corresponding to zone Z2 in the setting value shown in curve b in FIG. Make adjustment movements.

When the row of processed products 6 and dummy bodies 14 advances one step on the processing line 30 in FIG.
The processed product 6 or dummy body 14 subsequent to 4 is detected. In this way, one cycle of operation of the temperature control device 15 is completed. Thereafter, the process signal 8 is applied to the bus 25 of the temperature control device 15, and the same operation as described above is repeated.

Predetermined number of processing plans for type S processing product 6
When the processing of U _s is completed, it is determined in step 330 whether there are any subsequent processed products, and if there are any subsequent processed products, control returns to step 323, where the heat treatment of all processed products is completed and the subsequent processed products are processed. If not, control ends.

If not only the temperature distribution pattern but also the control parameters are stored in the storage device 20 for each zone according to the type S of the processed product 6, the control parameters are transferred from the storage device 20 to the adjustment means 50 when reading out the temperature distribution pattern. It is possible to perform adjustment operations based on the read control parameters.

storing in the storage device 20 a string of information consisting of the type and number of processed products 6 and the number of dummy bodies 14;
Further, when the processed products 6 and the dummy bodies 14 are arranged in a row according to the information string, the selection driving means 7
0 can be omitted.

When the selection drive means 70 is provided, the following configuration can be further used. That is, from the time when the setting means 60 sets the external temperature setting value for a certain furnace temperature distribution pattern, the internal temperature y ₁ of the processed product entrance terminal zone Z1 of the furnace 1 and the temperature distribution pattern specified at the time of the setting are changed. Temperature comparing means 46 (FIG. 5) for detecting a temperature difference Δt between P _s and the temperature P _1s of the terminal zone Z1 portion is provided, and the selection driving means 7 is provided until the temperature difference Δt becomes equal to or less than a certain value.
0 allows the dummy body 14 to continue to be fed into the furnace 1.

In addition, if the variation range of the temperature distribution pattern to be used is small enough that the heat transfer gain does not change, it is possible to memorize only a specific heating section temperature setting value pattern and use settings other than the memorized pattern. When a temperature distribution pattern requiring a value is required, the heating section temperature setting value may be determined and set by proportional calculation using inside or outside.

In order to increase the control speed, if necessary, the furnace temperature detector 31 may be of a fixed type installed in each zone instead of a movable type. In this case, the temperature inside the furnace, especially the distribution of the internal temperature, can be measured by switching the output of the fixed furnace temperature detector 31, thereby saving time for moving the movable type inside the furnace. I can do it.

Embodiment FIG. 9 is a block diagram showing in detail the essential parts of an embodiment of the temperature control device according to the present invention shown in FIG. Indicate by number. The multiplexer 16 sequentially applies temperature signals from the furnace temperature detector 31 and the temperature detection elements 4 of zones Z1 to Zn to the bus 25 via an analog/digital (A/D) converter 17. Digital/analog (D/A) converter 18 ₁ to 18n corresponding to each zone
converts the operation signals 5 ₁ to 5n on the bus 25 into digital signals and applies them to the operation units 3 ₁ to 3n.

A microprocessor (CPU) 19 that controls the operation of the temperature control device 15 and a storage device 20 are connected to the bus 25, as well as a display interface 21a of a display 21. In addition, storage device 2
A keyboard 22 used for inputting 0, etc. is connected to a bus 25 via a keyboard interface 22a.
connected to. A processed product signal 8 from a processed product detector 7 for counting processed products 6 and a signal on a signal line 33 from a temperature distribution pattern changeover switch 34 are applied to a bus 25 via an input/output interface 23. For example, one switching position of the changeover switch 34 corresponds to one temperature distribution pattern.

The operation of the embodiment shown in FIG. 9 will be explained. External temperature signals from the temperature detection elements 4 of each zone Z1 to Zn of the furnace 1 are switched at fixed time intervals by a multiplexer 16, converted by an A/D converter 17, and then added to a bus 25 as an input value of external temperature x. It is stored in the storage device 20. The internal temperature measurement value signal from the furnace temperature detector 31 is similarly digitized by the multiplexer 16 and then stored in the storage device 20 as the internal temperature y. The temperature distribution pattern signal P _{is is} applied to the bus 25 from the changeover switch 34 via the signal line 33 and the input/output interface 23, or is applied from the keyboard 22 to the bus 25 via the keyboard interface 22a, and is stored. It is stored in the device 20.

The CPU 19 stores the external temperature set value x _ir (step 302 in FIG. 6) for calculating the transfer gain corresponding to the temperature distribution pattern P is set from the keyboard 22 or specified by the changeover switch ₃₄ in the storage device 20 in this case. temperature setting element 40, which is a part of the temperature setting element 40. The CPU 19 then compares the input value with the set value, performs arithmetic operations, and generates operation signals ₅₁ to 5n so that the input value matches the set value. The operating signals 5 ₁ to 5n are applied to the operating units 3 ₁ to 3n via the D/A converters 18 ₁ to 18n to control the heating elements 2 .

Thereafter, the CPU 19 calculates the transfer gain g already explained with reference to FIG. 6, calculates and sets the external temperature set value _xs for the required temperature distribution pattern P,
The heat treatment for the processed product 6 is controlled.

In the embodiment shown in FIG. 9, the keyboard 22 or the changeover switch 34 functions as a part of the setting means 60 shown in FIG. , the selection drive means 70, and the calculation means 8
It has the effect of 0.

The display 21 is used to monitor signals when inputting a temperature distribution pattern from the keyboard 22, for example.

The embodiment shown in FIG. 9 uses a so-called multi-loop control device in which a plurality of loops are controlled by a single control device, but recently, so-called single-loop or one-loop distributed controllers are often used. FIG. 10 shows an embodiment of the invention using a distributed controller. Zones Z1 to Zn of furnace 1 are connected to single loop controllers 101 ₁ to 101n, respectively.
These single loop controllers are controlled by a computer 103 via transmission line 102.
It is connected to the. In this embodiment, the processed product signal 8 from the processed product detector 7 and the output of the pattern changeover switch 34 are directly interfaced to the computer 103, and the controller 101 ₁ -10
If 1n is capable of digital interface, the interface may be input to any of the controllers.

The furnace temperature detector 31 is connected to a temperature distribution measuring unit 105 via a signal line 104, and the unit 105 is connected to a computer 103 via a transmission line 102.

In the configuration of FIG. 10, the furnace temperature detector 3
1, the computer 103 calculates the heat transfer gain g based on the internal temperature y detected by the detector 31, calculates the set value _xs of the external temperature required to obtain the required temperature distribution pattern P, etc. computer 1
Since the capacity of the storage device 20 of No. 03 is considerably larger than that of a normal controller, it has the advantage of being able to store many temperature distribution patterns, types and quantities of processed items, etc.

Each controller 101 ₁ to 101n has a transmission line 1
It receives various setting values, control parameters, etc. from the computer 103 via 02, performs control based on these setting values, control parameters, etc.
The measurement results are transmitted to the computer 103. When changing the temperature distribution pattern, all or some of the controllers 1011 to _101n are connected to the computer 1.
From 03 onwards, the heating section temperature set value and control parameters corresponding to the new temperature pattern are sequentially received, and from that point onwards, control is performed under the new temperature set value and control parameters. In this manner, temperature control similar to that of the embodiment shown in FIG. 9 can be performed.

Effects of the Invention As explained above, the interference-compatible automatic pattern switching type temperature control device according to the present invention adjusts the set value of the furnace control part temperature, that is, the external temperature, for the required temperature distribution pattern, taking into account interference between zones. Furthermore, the temperature distribution pattern in the furnace is automatically switched for each zone in synchronization with the change in the type of product being processed inside the furnace, resulting in the following remarkable effects.

(a) It is possible to simultaneously achieve rapid and automated switching of the temperature distribution pattern in the furnace.

(b) The temperature distribution pattern in the furnace can be switched accurately, and the pattern after switching can be maintained accurately.

(c) In the case of high-mix, low-volume production, etc., automatic feeding of dummy bodies and automatic switching between processed products can be used to wait for the temperature inside the furnace to reach the required value, and then feed the processed products into the furnace without delay. Therefore, it is possible to improve the efficiency of the treatment process and the furnace utilization rate.

(d) The complicated manual operations conventionally required for switching temperature setting patterns can be omitted, saving not only labor and time but also power.

(E) A highly accurate temperature control system can be constructed by eliminating the timing deviation of setting value changes that accompanies manual switching.

(f) As a computer-combined system, it can store a large amount of temperature distribution patterns, etc., and can be applied to large-scale systems with many temperature adjustment points.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of a temperature control device according to the present invention applied to a tunnel furnace, Fig. 2 is an explanatory diagram of a temperature controller according to the prior art, Fig. 3 is an explanatory diagram of an adjacent block, and Fig. 4 is an explanatory diagram of a transfer gain. 5 is an explanatory diagram of the configuration of the device of the present invention, FIG. 6 is a flowchart showing the operation of the device of the present invention, FIG. 7 is a graph and explanatory diagram used to explain the operation of the present invention, and FIG. FIG. 9 is a detailed block diagram of a main part of one embodiment of the present invention, and FIG. 10 is a detailed block diagram of a main part of another embodiment of the present invention. 1...Furnace, 2...Heating element, 3...Operation unit, 4
...Temperature detection element, 5...Operation signal, 6...Processed product, 7...Processed product detector, 8...Processed product signal, 1
1...Processed product line, 12...Dummy line, 1
3... pusher, 14... dummy body, 15... temperature control device, 16... multiplexer, 17...
A/D converter, 18...D/A converter,
19... CPU, 20... Storage device, 21... Display, 22... Keyboard, 23... Input/output interface, 25... Bus, 27... Setting element,
28A-28N...controller, 30...processing line, 31...furnace temperature detector, 32...recorder,
33... Signal line, 34... Changeover switch, 40...
...Temperature setting element, 41...Processed product setting element, 45
... Counting means, 46 ... Temperature comparison means, 50 ...
Adjustment means, 60... Setting means, 70... Selection driving means, 80... Calculating means, 101... Single loop controller, 102... Transmission line, 103... Computer, 104... Signal line, 105... ...Temperature distribution measurement unit.

Claims (1)

[Scope of Claims] 1. A temperature control device for a furnace having a plurality of zones Z _i provided with heating section temperature detection elements and a furnace temperature detector for detecting the internal temperature of each zone,
A processing product setting element in which the scheduled number of processing products for a specific processing product is set; a temperature setting element in which a set value string x _i of the heating section temperature for each zone is set; a set x _ir of heating section temperature set value sequences of different values to be set, a plurality of temperature distribution patterns P _is , and an internal temperature detected by the in-furnace detector under the heating section temperature set value sequence of the set A storage device for storing the set y _ir of the set value sequence of different values; calculates the heat transfer matrix g _ij between the set x _ir of the set value string of different values and the set y _ir of the internal temperature, and uses the heat transfer matrix g _ij to Arithmetic means for calculating the set x _is of the set value sequence for the temperature distribution pattern P _is and storing it in the storage device; Counting means for counting the number of processed products to be heat-treated; and the count value of the counting means When the number of items to be processed matches the set value of the number of items to be processed in the item setting element, the number of items to be processed for the next subsequent item to be processed is read from the storage device to the item setting element, and the heating is performed for the next subsequent furnace temperature distribution pattern. 1. An interference compatible pattern automatic switching type temperature control device, comprising a setting means for reading out a series of temperature setting values for each zone from the storage device to the temperature setting element in synchronization with the progress of the processed product in the furnace. 2. In the automatic switching temperature control device according to claim 1, the set value sequence of different values is
a set of measured values detected by the heating section temperature detection element under the heating section temperature setting value of x _ir ; and a set of internal temperatures detected by the furnace temperature detector under the heating section temperature setting value. y _ir , in which the calculation means calculates a heat transfer matrix g _ij . 3. An automatic pattern switching temperature control device according to claim 1, comprising a switching switch means for selecting the temperature distribution pattern of the storage device. 4. In the automatic switching temperature control device according to claim 1, the difference between the temperature detected by the temperature detection element in each zone and the temperature in the set value string read out to the temperature setting element for that zone. an interference-compatible automatic pattern switching temperature control device, comprising adjusting means for operating said heating element of said zone according to said interference-compatible pattern automatic switching temperature control device; 5. In the automatic switching temperature control device according to claim 4, control parameters for each type of processed product are stored in the storage device for each zone, and when the setting value string is read by the setting means, An interference compatible pattern automatic switching type temperature control device, wherein the control parameters are read out to the adjustment means by the setting means. 6. The automatic pattern switching temperature control device according to claim 4, wherein the planned number of dummy bodies to be processed is added to the column of the planned processing number. 7. In the automatic switching temperature control device according to claim 6, when the planned number of each processed product or dummy body is counted by the coefficient means, the subsequent dummy body or processed product is selectively An interference compatible pattern automatic switching type temperature control device that is equipped with a selective drive means for feeding the feed into the furnace. 8. In the automatic switching temperature control device according to claim 7, when the setting value string is read by the setting means, the internal temperature of the processed product entry terminal zone of the furnace and the temperature distribution in the subsequent furnace are determined. An automatic interference compatible pattern is provided with a temperature comparison means for detecting a temperature difference between the terminal zone temperature and the temperature of the terminal zone in the pattern, and the dummy body is fed into the furnace by the selection drive means until the temperature difference becomes below a certain value. Switchable temperature control device. 9. The automatic switching temperature control device according to claim 4 or 5, wherein the adjustment means is a multi-loop adjustment means that generates an operation signal for the heating means of each zone, and an interference compatible pattern automatic switching device is provided. temperature control device. 10. In the automatic switching temperature control device according to claim 4 or 5, the adjustment means comprises a plurality of units provided for each zone and having a temperature setting element and a control parameter element for the zone. An interference compatible pattern comprising a loop controller, a computer having a storage device and a transmission means for the temperature distribution pattern and the control parameters, and a transmission line connecting the plurality of single loop controllers and the computer. Automatic switching temperature control device.