JPH0452216A - vacuum furnace - Google Patents

Abstract

PURPOSE:To heat the whole material to be treated under uniform temp. distribution by heating the material to be treated with heaters at each face side of upper face, lower face and side faces and controlling calorific value of the heater with the detected value from a temp. detector attached to a dummy material which heat effect from the heater can be received as the same as that of the material to be treated. CONSTITUTION:To the material 31 to be treated, the heat from each heater 12a-12f at the upper face side, lower face side and side face sides, is given to uniformly heat the whole material. In the case of heating as the above, the dummy material 13 receives the heat from each heater, too and the temp. raises. The temp. raising of dummy material is detected with the temp. detector 14, and based on this detected value, the calorific value of the above heater is controlled. In the case of controlling as the above, based on the detected value with one temp. detector, the calorific value of each heater is controlled under condition of giving deflection preset in a deflection setter 29. In this result, the material 31 to be treated is heated under condition of uniformizing the whole temp.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vacuum furnace used for subjecting various materials to heat treatment such as quenching, tempering, sintering, and firing.

[Prior Art] In this type of furnace, for example, heaters are provided on the upper surface side and the lower surface side of the space where the material to be treated is placed in a vacuum container, and a temperature sensor is installed to detect the temperature of the material to be treated. A detector is provided, and the amount of heat generated by the heater is controlled based on the detected value.

In such a vacuum furnace, the material to be processed is heated only from the upper and lower surfaces, so there is a problem in that the side surfaces are not sufficiently heated, resulting in a large temperature difference between the upper and lower surfaces. Therefore, a technique has been devised in which a heater and a temperature detector are separately provided in order to heat the side surface side as well, and the heater for heating the side surface side is controlled based on the detected value by the temperature sensor.

[Problems to be Solved by the Invention] However, even if heaters are provided on each surface as described above and the amount of heat generated by the heaters is controlled based on the detected value of the temperature detector, the following problem occurs. There is a problem. That is, since the material to be treated placed in the storage space is replaced, the temperature detector is placed at a position that avoids the storage space. Since the temperature sensor at this position is affected by the temperature from the material to be processed, the detected value of the temperature detector corresponds to the temperature of the material to be processed. Therefore, considering the correspondence,
Estimate the temperature of the material to be treated using the detected value of the temperature detector,
The heater is controlled. However, if the stacking method or shape of the materials to be treated changes in the storage space, the distance between the materials to be treated and the temperature sensor will change, and for a temperature sensor installed independently, the difference in distance will affect the above correspondence relationship. Makes a big difference. Then, the temperature of the material to be treated estimated from the detected value of the temperature detector differs from the actual temperature of the material to be treated. As a result of controlling the amount of heat generated by the heater based on such an erroneous value, there is a problem in that the material to be treated is heated to an erroneous temperature.

The present invention has been made in order to solve the problems (technical problems) of the prior art described above, and it is possible to heat the material to be treated by heaters on each of the upper, lower and side surfaces of the material, and also to heat the material from the heater. By providing a dummy material that can be affected by heat in the same way as the material to be processed, and controlling the output PAN of the heater using the detected value from the temperature sensor attached to the dummy material, the stacking of the material to be processed can be reduced. The purpose of the present invention is to provide a vacuum furnace that can always accurately detect the temperature of a material to be processed, even if its orientation or shape changes, and can heat the entire material to be processed with a uniform temperature distribution. shall be.

[Means for Solving the Problems] In order to achieve the above object, the vacuum furnace of the present invention has a vacuum container having a storage space for a workpiece inside, and a In a vacuum furnace, the vacuum furnace is equipped with a heater for heating the material to be processed that is placed in the storage space on the side surface side, and a temperature detector for detecting the temperature of the material to be processed in the vacuum container. A dummy material is disposed near the storage space, and the temperature detector is attached to the dummy material, while a heat generation amount controller is connected to the power supply path of each heater, respectively. Each heater is individually installed, and an individual deviation setting device is interposed between the calorific value regulator and the temperature detector so that the calorific value of each of the heaters can have a deviation. It is.

[Operation] Heat is applied to the material to be treated from the heaters on the upper surface side, lower surface side, and side surface side, and the entire surface is uniformly heated. In the case of the above heating, the dummy material also receives heat from each heater and its temperature increases. The temperature rise of the dummy material is detected by a temperature detector, and the amount of heat generated by the heater is controlled based on the detected value.

In the case of the above control, the amount of heat generated by each heater is controlled with a deviation preset in the deviation setting device based on a value detected by one temperature detector. As a result, the material to be processed can be heated with the entire temperature being made uniform.

[Example code] The drawings showing the embodiments of the present application will be described below.

In Figure 1.2, 1 indicates a vacuum furnace. Reference numeral 2 denotes a vacuum container, which is composed of a main body 3 and a door 4 provided at the entrance and exit of the main body 3. Reference numeral 5 denotes a heat insulating wall, which is composed of a main body 6 and a door 7 provided at the entrance/exit of the main body 6, and the space inside thereof serves as a heat treatment chamber 8.

Reference numeral 10 denotes a mounting table provided in the heat treatment chamber 8, and the space above it serves as a storage space 11 for the material to be treated.

12a to 12r are heaters disposed around the storage space 11, and are provided on the upper surface side, lower surface side, and left, right, front, and rear sides of the storage space 11, respectively. (In this specification, the door side is called the front, the opposite side is called the back, and left and right refer to the left and right as seen from the door side), each of which is attached to one heat wall. heaters 12e on the front side and rear side;
In some cases, 12f is not provided. Reference numeral 13 indicates a dummy material (storage space 1
1), and are made of material, shape, and size similar to the intended material to be processed. Reference numeral 14 denotes a temperature detector attached to the dummy material 13, which is capable of detecting high temperatures, and uses a thermocouple, for example.

Next, FIG. 3 showing the control system of the heaters 12a to 12f will be explained. In FIG. 3, lowercase letters a to f attached to the reference numbers indicate that each member indicated by the reference number corresponds to each of the heaters 12a to 12f, and in the following, Except when necessary, explanations will be given using symbols omitting lowercase letters a to f.
, 25 are power supply terminals connected to a commercial power supply. Reference numeral 26 denotes a heat generation amount regulator interposed in the power supply path to the heater, and for example, a current regulator is used. For example, a thyristor is used as such a current interval ms. Reference numeral 28 denotes a well-known temperature controller which outputs a control signal based on the detected temperature value obtained from the temperature detector 14.

A deviation setting device 29 receives a control signal from the temperature controller 28, adds a preset deviation value to the control signal, and sends the signal to which the deviation value has been added to the current controller 2.
It is designed to be given to 6.

Next, heat treatment of a material to be treated using the vacuum furnace will be explained.

The doors 4 and 7 are opened, and the material to be processed 31 is placed on the mounting table 10. The placed state is as shown in the figure (the state in which the small processed materials 31 are stacked on a shelf, and the large ones are placed alone on the stand 10. Then, the door 4.7 is closed, and the vacuum container 2 The interior of the heaters 12a to 12f is evacuated, the heaters 12a to 12f are energized to generate heat, and the heaters 12a to 12
The material to be treated 31 is heated mainly by radiant heat transfer from f.

In the case of the above-mentioned heating, the temperature of the material to be treated 31 is measured by the temperature detector 14.
Based on the signal therefrom, the current regulator 26 is controlled via the temperature controller 28 and the deviation setting device 29, and the output of each heater 2a to 12f is controlled. IIJvs of the outputs of these heaters 12a to 12f is performed with a deviation set in advance in the deviation setting device 29.

Therefore, all parts of the material 31 placed in the storage space 11 are heated to a substantially uniform temperature.

The temperature of the material to be treated is detected by the temperature detector 14 as follows. Since the temperature detection l514 is attached to the dummy material 13, the temperature detection S14 directly detects the temperature of the dummy material 13. Since the dummy material 13 is formed as described above, the processing material 31 and the dummy material 1 due to the difference in shape and arrangement of the processing material 31 left in the storage space 11
The difference in distance from the dummy material 13 has a small effect on the temperature rise of the dummy material 13, and the dummy material 13 receives the same heat from the heater as the material to be processed 31, and its temperature rises substantially in the same way as the material to be processed 31. Therefore, the temperature detector 14 can accurately measure the temperature of the material 3 to be treated.
Detect the temperature of 1.

Therefore, the output of the heater can be controlled with high precision.

The deviation values to be set in the improvement reporter deviation settings 5293 to 29f are determined depending on the shape, size, and loading state of the material 31 in the storage space 11, respectively. It is best to experimentally determine in advance various values that can make the temperature uniform, and then select and use one of these values that suits the actual situation.

Once the material to be processed 31 has been heated to a predetermined level as described above, the power supply to the heater is stopped, and cooling gas is introduced into the vacuum container 2 and provided in the vacuum container 2. The material to be treated 31 is cooled by the operation of a well-known roller or fan.

When the cooling is finished, the doors 4 and 7 are opened and the processed material 31 that has undergone heat treatment is taken out.

Next, when the temperature distribution width in the furnace was actually measured in the case where the dummy material 13 as described above was not used and in the case where it was used, improvements as shown in Table 1 below were observed.

Table 1 Next, in the above embodiment, an example was given in which the heat insulating wall was arranged in a square cross-sectional shape as shown in FIG. They may be arranged in a cylindrical shape corresponding to the shape of.

Next, FIG. 4.5 shows a different embodiment of the present application, and shows an example in which a plurality of heaters are controlled by the detected values of temperature detectors provided individually. That is, the dummy members 138 to 13f are arranged on the upper surface side, the lower surface side, and the left, right, front, and rear side surfaces of the storage space 11x, respectively.

Temperature detectors 14 are installed on each of those dummy materials 138 to 13f.
8 to 14f are attached individually. Temperature controllers 28a to 28f are connected to each temperature detector, and the heat output a-breakers 26ax to 26fχ of each heater are connected to the temperature detectors 142 to 14f on each side via each temperature controller. be.

In such a control system, each of the temperature detectors 14
Based on the detected value of 2 to 14f, the heater 1 on the same side as that
Since the heat generation amount of 2ax to 12fx is individually controlled, even if the size, shape, and arrangement of the material to be processed placed in the holding space 11x changes, the output of the heaters on each side is automatically adjusted accordingly. , any material to be treated can be heated with uniform temperature distribution.

In addition, parts that are functionally the same or equivalent to those in the previous figure are marked with the same symbols as in the previous figure and an X in the alphabet.
The redundant explanation has been omitted by adding .

(Also, Alphabear will use the same idea for the next one)
The redundant explanation will be omitted by adding y. ) Next, FIG. 6 shows a further different embodiment of the present invention, in which a dummy material can be selected depending on the type of material to be treated.

In the figure, 13' to 132' are dummy materials of different types. Examples of such types include size,
There are different shapes, materials, etc., and they are available in different shapes and materials. Temperature detectors 14'' to 14'' are attached to each of the dummy members 13'' to 13'', respectively. 33 is a switching means, for example, a switch is used, and each switching contact thereof is connected to each of the temperature detectors 14'' to 14'',
The common contact point is connected to each calorific value controller (
In the figure, only the calorific value double cut 526fy is shown).

In the above configuration, by operating the switching means 33, the dummy material 13° similar to the material to be heated is heated.
By selecting the temperature detectors 14° to 141 attached to 131, the temperature of any material to be treated can be detected with high accuracy, improving the reliability of heater output @ control. I can do it.

[Effects of the Invention] As described above, in the present invention, when heating the material 31 to be treated, heat is applied to the material 31 from the heaters 12a to 12f on the upper surface side, lower surface side, and side surface side. Because you will be
Of course, it has the effect of uniformly heating the entire material 31 to be processed, and in the case of the above heating, the temperature detector 14
and detects the temperature of the heater 12 based on the detected value.
Since the calorific value of a to 12f is controlled, there is an effect that heating can be performed in accordance with the temperature condition of the material to be processed 31.

Moreover, since the temperature detector 14 is attached to the dummy material I3, the temperature of the material to be processed 31 is detected as described above, and the amount of heat generated by the heaters 12a to 12f is controlled based on the detected value. When performing heating, even if the stacking method or shape of the material to be processed 31 changes, the difference in distance between the material to be processed 31 and the temperature sensor 14 caused by such changes will not affect the temperature detection 514. Can be made small and processed material 3
1 can be detected with high accuracy, and the material to be processed 31 can be heated to an appropriate temperature.

Furthermore, in the present invention, in the case of the above control, even if the temperature is detected by the temperature detector 14 at one location, the amount of heat generated by each of the heaters lQa to 12f can be controlled with a deviation from each other. Therefore, the material to be treated 31 has the feature that the temperature can be controlled over the entire area in the same manner as when each of the heaters 12a to 12f is individually controlled. This has the requirement that it is possible to simplify the control network for equalizing the temperature of the material to be treated.

In addition, in the present invention, a plurality of dummy materials 13" of different types
~13'', when heating various materials to be treated, a temperature detector used for control is attached to a dummy material similar to the material to be treated.
By switching to "°", no matter which material to be treated is heated, it is possible to heat each material to an appropriate temperature with high precision.

Furthermore, in the present invention, when temperature detectors 142 to 14f with dummy materials are provided on each side of the storage space 11X and the calorific value of each heater 12ax to 12fx is controlled by each, the material to be treated may be changed. Even if the temperature is detected on each surface side and control is performed based on the detected value, it is possible to properly heat any material to be processed.

[Brief explanation of drawings]

The drawings show an embodiment of the present application, and FIG. 1 is a vertical sectional view of a vacuum furnace, FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1 to show the arrangement of the heater, and FIG. 4 is a longitudinal sectional view of a vacuum furnace showing different embodiments, FIG. 5 is a circuit diagram showing different embodiments of the heater control system, and FIG. 6 is a further different embodiment. Partial view shown. 2... Vacuum container, 11... Storage space, 12a-12
f... Heater, 13... Dummy material, 14... Temperature detector, 26... Calorific value regulator, 29... Deviation setting device.

Claims (1)

[Claims] 1. In a vacuum container having a space for holding a material to be processed inside, the material to be processed placed in the space is heated on the upper surface side, the lower surface side, and the side surface side of the space, respectively. In a vacuum furnace that is equipped with a heater to detect the temperature of the material to be processed, and a temperature detector in the vacuum chamber to detect the temperature of the material to be processed, a dummy material is placed near the above-mentioned storage space, and A temperature detector is attached to the dummy material, and on the other hand, a calorific value regulator connected to the temperature detector is individually interposed in the power supply path of each of the heaters, and these calorific value regulators and A vacuum furnace characterized in that an individual deviation setting device is interposed between the temperature detector and the heater so as to provide a deviation in the amount of heat generated by each of the heaters. 2. Multiple dummy materials of different types are provided,
Each dummy material is individually attached with a temperature detector, and the temperature detectors are connected to switching means for selectively using each one, and each deviation setting device is connected to the switching means. A vacuum furnace according to claim 1. 3. In a vacuum container having a storage space for the material to be processed inside, heaters are provided on the upper surface side, lower surface side, and side surface side of the storage space to heat the material to be processed stored in the storage space, respectively. Furthermore, in a vacuum furnace equipped with a temperature detector for detecting the temperature of the material to be processed in the vacuum chamber, dummy materials are arranged on the upper surface side, lower surface side, and side surface side of the above-mentioned storage space, respectively. Temperature detectors are individually attached to each of these dummy materials, and heat generation amount regulators are individually interposed in the power supply paths of each of the heaters. The heat generation amount of each heater can be controlled individually based on the detected value of the temperature sensor on the same side as the heater.
A vacuum furnace characterized by being connected to a temperature sensor on each side.