JP7525948B1 - High Temperature Furnace - Google Patents

Abstract

A novel high-temperature furnace (1) is provided.
[Solution] A hot air generator 3 for heating and circulating the atmosphere in a high-temperature furnace 1, and a plurality of stations 4 for moving a workpiece W while being placed thereon are provided. Each station 4 includes a first heater 5 for heating the workpiece W from the left and right, and a second heater 6 for heating the workpiece W from above and below.
[Selected figure] Figure 3

Description

This disclosure relates to high temperature furnaces.

A hybrid type continuous tempering heat treatment machine as described in Patent Document 1 is known as a continuous furnace for heat treating workpieces. The heat treatment machine of Patent Document 1 includes a transport path for transporting metal workpieces, a heating zone including a far-infrared irradiation device that heats the workpiece to a predetermined target temperature and a hot air blowing device that blows hot air at a temperature higher than the outside air temperature, and a heat retention zone including a hot air blowing device that blows hot air at a temperature higher than the outside air temperature onto the workpiece and maintains the heated workpiece at the target temperature. In the heating zone, the hot air blowing device and the far-infrared irradiation device are arranged on either side of the transport path. In a heat treatment line including such a heat treatment machine, a series of processes such as quenching, tempering, and cooling are continuously performed on the workpiece.

Patent No. 5129249

In general, in a heating furnace for heat treatment of a workpiece as described in Patent Document 1, the heater is not in direct contact with the workpiece for heating. In a continuous furnace, the workpiece is transported by a conveyor, but the entire production line may be temporarily stopped due to an abnormality. In such a case, the workpiece must not be too cold or too warm. Such a workpiece may be discarded. Since a normal production line is an air atmosphere, unlike a vacuum furnace, it is difficult to maintain the atmospheric temperature for a short period of time. For delicate workpieces such as electromagnetic steel sheets, it is desirable to stop the furnace and turn it on again. However, there is an issue that it takes time and cost to restart the furnace. Also, in a production line with a large number of electrical components, there is an issue that it is desirable to avoid heat effects as much as possible.

This disclosure has been made in consideration of these points, and aims to provide a novel high-temperature furnace.

The high temperature furnace of the present disclosure comprises:
A hot air generator for heating and circulating the atmosphere inside the furnace;
A plurality of stations on which workpieces are placed and moved;
Equipped with
Each of the stations includes a first heater for heating the workpiece from the left and right sides, and a second heater for heating the workpiece from above and below.

In the high temperature furnace of the present disclosure,
One of the second heaters may contact the workpiece to heat it. Also, the second heaters may contact the workpiece from above and below to heat it.

In the high temperature furnace of the present disclosure,
The first heater may be a ceramic heater, and the second heater may be a cartridge heater.

The high temperature furnace of the present disclosure comprises:
The station includes a placement portion,
The platform may be configured to move the workpiece forward to enable cyclic movement through each of the stations.

The high temperature furnace of the present disclosure comprises:
A first control unit that controls the operation of the high-temperature furnace;
A second control unit that controls the temperature of the high-temperature furnace;
The device may further include:

In the high temperature furnace of the present disclosure,
The second control unit may be a PLC that enables centralized temperature control through various combinations of a plurality of temperature sensors, a plurality of the first heaters, and a plurality of the second heaters.

In the high temperature furnace of the present disclosure,
When a current sensor detects a break in a power line of the first heater or the second heater, the second control unit may stop the first heater and the second heater.

In the high temperature furnace of the present disclosure,
When it is determined that the cycle operation cannot be performed, a warming mode may be set to keep the workpiece warm.

The high temperature furnace of the present disclosure comprises:
The heater further includes an air cylinder on which the second heater is mounted,
The air cylinder may move the workpiece up and down.

The high temperature furnace of the present disclosure comprises:
The apparatus may further include a shifter for changing the trajectory along which the work moves.

The present disclosure provides a novel high-temperature furnace.

FIG. 1 is a perspective view showing an external appearance of a high temperature furnace according to the present disclosure. FIG. 2 is a perspective view showing the high temperature furnace of FIG. 1 with the cover removed. FIG. 2 is a cross-sectional view showing an internal configuration of a station included in a high-temperature furnace. FIG. 11 is a diagram showing an example of movement of a workpiece in a station. 13A and 13B are diagrams illustrating another example of the movement of a workpiece in a station. FIG. 2 is a diagram showing an example of components to which a first control unit and a second control unit of a high-temperature furnace are connected to perform their respective controls. 7A is a diagram showing a correspondence relationship between a conventional temperature sensor and a heater in temperature control, and FIG. 7B is a diagram showing a correspondence relationship in the high-temperature furnace of the present disclosure.

Below, an embodiment of the present invention will be described with reference to the drawings, but the present invention is not limited thereto. In this specification, the term "workpiece" is used in the usual sense to include a workpiece (to be machined), and is not particularly limited. The workpiece may be a metal workpiece, such as a SUS plate, SPCC plate, or electromagnetic steel plate, and there are no limitations on its use, dimensions, etc. In addition, the front of the workpiece refers to the direction in which the workpiece is transported or travels, unless otherwise specified.

[Configuration of high temperature furnace 1]
First, the configuration of the high-temperature furnace according to the present disclosure will be described. FIG. 1 is a perspective view showing the appearance of the high-temperature furnace 1 according to the present disclosure, and FIG. 2 is a perspective view showing a state in which the cover 2a is removed from the high-temperature furnace 1 of FIG. 1. As shown in FIGS. 1 and 2, the high-temperature furnace 1 of the present disclosure includes a hot air generator 3 for heating and circulating the atmosphere inside the furnace, and a plurality of stations 4 in which the workpieces W are placed and moved. The successive stations 4 form one continuous furnace that shares a transport path for the workpieces W. By repeatedly transporting the workpieces W to each station 4 and heating them while heating and circulating the atmosphere inside the high-temperature furnace 1 with the hot air generator 3 (hereinafter also referred to as a cycle operation), efficient heating of the workpieces W can be realized.

In the example shown in FIG. 1, the high-temperature furnace 1 is equipped with a cover 2a for the safety of workers in the workplace. The cover 2a may also have a ceiling portion equivalent to a lid, and an air intake and exhaust fan and an air intake and exhaust port may be provided on the ceiling portion or side of the cover 2a. In addition, a shutter (door) 2b may be provided at the exit and entrance of the transport path inside the high-temperature furnace 1 to prevent outside air from entering and to keep the temperature constant. The cover 2a and the shutter 2b serve to define the high-temperature furnace 1 from the outside.

(Hot air generator 3)
The hot air generator 3 generates hot air to heat and circulate the atmosphere in the high-temperature furnace 1. The hot air generator 3 generates hot air that circulates in the high-temperature furnace 1. In a heat retention mode described later, even if the first heater 5 and the second heater 6 are controlled to stop, the high-temperature furnace 1 may be heated only by the hot air generator 3 to keep the workpiece W warm. The hot air generator 3 is not particularly limited as long as it has such an effect. The type and set temperature of the hot air are also not limited, and can be appropriately changed according to the heating target temperature of the workpiece W, etc.

In the example shown in Figures 1 and 2, two hot air generators 3 are shown for heating the outbound and inbound paths of the transport path of the workpiece W, but the number of hot air generators 3 is not limited and may be one. A person skilled in the art can appropriately install pipes for directing hot air from the hot air generators 3, fans for promoting convection of hot air, etc., inside the high-temperature furnace 1.

(Station 4)
As shown in Fig. 3, each station 4 includes a first heater 5 for heating the workpiece W from the left and right, and a second heater 6 (6a, 6b) for heating the workpiece W from above and below. As a result, the workpiece W can be heated uniformly and in a short time by heating from above, below, left and right in the station 4. In the example shown in Fig. 3, a heat insulating material 16 is provided around the first heater 5, the second heater 6 and the air cylinder 10, and this heat insulating material 16 serves to insulate the workpiece from the outside air.

As a means of transportation, the workpieces W may be moved between multiple stations 4 by placing the workpieces W on a belt conveyor and passing them continuously through each station 4. With such a belt conveyor system, the workpieces W can be kept at a constant height, which allows for simplification of the high-temperature furnace 1.

As another conveying means, each station 4 includes a placement section 7, and when the workpiece W enters the station 4 (see FIG. 3), the workpiece W may be placed on the placement section 7 and passed through the station 4. The placement section 7 can move the workpiece W forward to enable cyclical movement in each station 4. In this way, the heating and movement of the workpiece W are repeated in multiple stations 4 (cyclical movement), and the intermittent heating process can suppress the variation in the degree of heating (single-wafer type). In addition, if a mechanism capable of moving the workpiece W up and down is further provided (for example, a linear actuator or an air cylinder 10 described later), the workpiece W can be lifted toward the upper second heater 6a, thereby realizing contact heating and the workpiece transfer operation from the placement section 7. It is preferable that the placement section 7 is made of a heat-resistant material. The shape and structure of the placement section 7 for placing the workpiece W are not particularly limited. For example, the placement unit 7 may have a hollow box-like structure without a top or bottom surface, and the second heater 6b on the lower side may be able to move up and down through the inside of the box. The placement unit 7 may also have a structure that supports the opposing ends of the workpiece W (for example, a structure that has two parallel plate-like members, and the second heater 6b can move up and down between them).

With reference to Figures 4 and 5, an example of the upward and downward forward movement of the workpiece W in station 4 in the above-mentioned single-wafer type will be described. Note that the open arrows indicate the movement of the workpiece W and the second heaters 6a, 6b, etc., and the filled arrows indicate heating. First, Figure 4(a) shows the state immediately before the workpiece W supported by the jig 8 described later is placed on the placement part 7 (equipped with multiple feed claws) and enters the inside (station 4) of the high-temperature furnace 1 from the outside. Note that, in order to explain the movement of the workpiece W, members such as the first heater 5 of station 4 are omitted. Next, the workpiece W is sent into the high-temperature furnace 1 (station 4) by the placement part 7 (Figure 4(b)). As shown in Figure 4(b), the workpiece W in this state is not in contact with the upper and lower second heaters 6a, 6b (there is a gap). Next, from the state of Figure 4(b), the lower second heater 6b rises and the upper second heater 6a falls (Figure 4(c)). As a result, the workpiece W is lifted and removed from the placement section 7. The upper and lower second heaters 6a and 6b also come into contact with the workpiece W. The workpiece W is then heated. Next, in the state of FIG. 4(c) where the upper and lower second heaters 6a and 6b are in contact with the workpiece W, the feed claws of the placement section 7 return by one pitch, i.e., move backward (FIG. 4(d)). Next, the upper second heater 6a rises and the lower second heater 6b falls (FIG. 4(e)). As a result, the workpiece W remains on the placement section 7 again. Also, as shown in FIG. 4(e), another workpiece W is set on the returned feed claws (placement section 7). In this manner, the cycle operation is repeated.

Figure 5 shows another aspect of the movement of the workpiece W in station 4 in the single-wafer type. In this example, the upper second heater 6a is fixed, and only the lower second heater 6b moves up and down. Figures 5(a) and (b) are in the same state as Figures 4(a) and (b), so their explanations are omitted. From the state of Figure 5(b), only the lower second heater 6b rises (Figure 5(c)). As a result, the workpiece W is lifted and removed from the mounting portion 7, and the workpiece W comes into contact with both the lower second heater 6b and the upper second heater 6a. Then, the workpiece W is heated. Next, in the state of Figure 5(c) where the upper and lower second heaters 6a and 6b are in contact with the workpiece W, the feed claws of the mounting portion 7 return by one pitch, that is, move backward (Figure 5(d)). Next, the lower second heater 6b descends (Figure 5(e)). As a result, the workpiece W is released from contact with the upper and lower second heaters 6a, 6b, and the workpiece W is left on the placement section 7 again. Also, as shown in FIG. 5(e), another workpiece W is set on the returned feed claw (placement section 7). In this manner, the cycle operation may be repeated. In this case, in addition to being able to suppress variations in the degree of heating by the intermittent heating process, the structure of the high-temperature furnace 1 can be simplified by fixing the position of the second heater 6a. The size of the high-temperature furnace 1 is also made compact, allowing for space savings.

Alternatively, the workpiece W may be transported by a belt conveyor as a transport means, while one or both of the upper and lower second heaters 6a, 6b are raised and lowered in each station 4 before heating the workpiece W (a hybrid type of belt conveyor type and single-wafer type). In the example of Figure 3, a belt conveyor is provided instead of the placement section 7 to move only the second heater 6a, or a belt conveyor is provided that does not interfere with the up and down movement of the second heater 6b. Such a hybrid type can simplify the high-temperature furnace 1 and also suppress variations in the degree of heating due to heat radiation.

In one embodiment, a metal jig 8 on which the workpiece W is placed as shown in Figures 2 and 3 may be used. In the example shown in Figure 3, the jig 8 has a base on which the workpiece W is placed and a support connected to the base for fixing the disk-shaped workpiece W. When the workpiece W is heated, the jig 8 is also heated, so that the workpiece W is heated from the inside through the jig 8, allowing the workpiece W to be heated more uniformly.

The dimensions of each station 4 are not particularly limited, and can be appropriately modified to suit the shape, size, material, etc. of the workpiece W, thereby enabling the quality of the workpiece W to be maintained.

The number of stations 4 is not particularly limited, but the more stations 4 there are, the better in order to increase the discharge cycles from stations 4 and shorten the heating time for each station 4. However, taking into account the power consumption for heating, it is preferable that the number of stations 4 be 10 to 20.

(First heater 5)
The first heater 5 heats the workpiece W from the left and right sides in the station 4. There are no particular limitations on the first heater 5, but it is preferable to use a ceramic heater that can heat the workpiece W by radiant heat. In the example shown in Fig. 3, the first heater 5 does not contact the workpiece W and is fixed to the station 4.

(Second heater 6)
The second heaters 6 heat the workpiece W from above and below in the station 4. By heating the workpiece W from above and below in this manner toward the center of the workpiece W, heat can be transferred uniformly. The type of the second heaters 6 is not particularly limited, but a cartridge heater is preferable. The number of second heaters 6 in each of the upper and lower parts of the station 4 is also not limited, and can be appropriately changed depending on the size of the station 4.

The second heater 6 can also heat the workpiece W by contacting it from above and below. At least one of the second heaters 6 (for example, the second heater 6a in FIG. 3) contacts the workpiece W to heat it, which leads to more efficient heating, shorter heating time, and more stable temperature. In the example shown in FIG. 3, a heater plate 9 is provided that contacts the upper and lower second heaters 6 (6a, 6b), and the heater plate 9 has a recess that fits into the support of the jig 8, so that heat from the second heater 6a is transferred to the workpiece W from above and inside via the heater plate 9 and the jig 8. Heat from the second heater 6b is also transferred to the workpiece W from below and inside via the heater plate 9 and the jig 8. The thickness and length of the heater plate 9 may be different between the top and bottom. The amount of heat from the second heater 6a may be the same as or different from the amount of heat from the second heater 6b, and can be changed appropriately depending on the height, volume, etc. of the workpiece W to be heated.

The high-temperature furnace 1 may further include an air cylinder 10 carrying the second heater 6. The air cylinders 10 may be provided above and below, with one pressing the second heater 6a and the other lifting the second heater 6b. These air cylinders 10 can move the workpiece W up and down via the second heaters 6a and 6b. In addition, a pressure suitable for holding and moving a workpiece W of, for example, 1 kg can be generated by the weight of the second heater 6 or the thrust of the upper air cylinder 10.

[Control system]
The high-temperature furnace 1 may further include a first control unit 11 for controlling the operation of the high-temperature furnace 1 and a second control unit 12 for controlling the temperature of the high-temperature furnace 1. The first control unit 11 and the second control unit 12 may each be configured with a microcomputer including a CPU and a semiconductor memory. In particular, an example of the second control unit 12 is a PLC (Programmable Logic Controller). FIG. 6 is a diagram showing an example of components of the high-temperature furnace 1 connected to the first control unit 11 and the second control unit 12 for performing their respective controls. In this way, by providing two control units performing different controls, temperature management can be performed centrally.

In temperature control, it is common to assign one temperature sensor to one heater (fixed to three channels in the example at the top of Figure 7 (A)), but if a PLC is used as the second control unit 12, the range of combinations of heaters and temperature sensors will be wider (Figures 7 (B) and (C)). That is, as shown in Figure 7 (C), one temperature sensor (e.g., thermocouple 13) can correspond to multiple heaters (first heater 5, second heater 6), and multiple temperature sensors can also correspond to one heater. Here, one temperature sensor may correspond, for example, to only heaters of the same type, only heaters in one station 4, or heaters in multiple stations 4. In addition, it is also possible to use PLC control to assign 11 sensors to 40 heaters, for example. In this way, the heater and temperature sensor are not limited to a 1:1 or n:1 relationship, and n:n control that enables centralized temperature control by various combinations of multiple temperature sensors and multiple heaters can be realized by the PLC, and the temperature rise time can be shortened and stabilized (at start-up, insertion, and removal). The type of thermocouple 13 can be appropriately selected depending on the heating temperature of the workpiece W.

The high-temperature furnace 1 may further include a current sensor 14. When the current sensor 14 detects a break in the power line of the first heater 5 or the second heater 6, the second control unit 12 may stop the first heater 5 and the second heater 6. When the second control unit 12 determines that either of the power lines has been broken by the current sensor 14, the second control unit 12 may stop the first heater 5 and the second heater 6 to prevent the workpiece W from overheating. The first control unit 11 may also stop the operation of the station 4 and the transport means. The type of the current sensor 14 is not particularly limited, and one having a similar function may be used.

When it is determined that the above-mentioned cycle operation cannot be performed, the high-temperature furnace 1 is set to a heat retention mode. The first control unit 11 may automatically switch to the heat retention mode, or it may be manually switched to the heat retention mode as one of the emergency response measures. In the heat retention mode, the workpiece W can be kept warm by operating only the hot air generator 3. That is, the left and right first heaters 5 and the top and bottom second heaters 6 are stopped, and the temperature inside the furnace (workpiece temperature) is controlled only by the convection of hot air from the hot air generator 3. Alternatively, all heaters may be operated, and the second heater 6 may be moved away from the workpiece. As another embodiment of the heat retention mode, only the first heater 5 may be stopped. The reason for setting the heat retention mode is that if the first heater 5 and the second heater 6 continue to operate while the workpiece W is stagnant, the temperature inside the high-temperature furnace 1 tends to rise. In this way, even if a problem occurs in the production line, the heating process can be continued rather than interrupted. There is also no need to use special heat-insulating materials.

The high-temperature furnace 1 may also be equipped with a safety PLC connected to the second control unit 12. If a normal signal is sent from the second control unit 12 to the safety PLC, the first heater 5 and the second heater 6 will output normally, and if the second control unit 12 fails or cannot be controlled normally, the safety PLC may be designed to cut off the power to the first heater 5 and the second heater 6. In this case, the operation of the hot air generator 3 will also stop, but the safety of the high-temperature furnace 1 can be guaranteed.

(others)
The high-temperature furnace 1 may be equipped with a shifter 15 for changing the trajectory of the workpiece W, such as by making a U-turn. The shifter 15 makes the high-temperature furnace 1 U-shaped instead of linear, as shown in Figures 1 and 2, making it possible to increase the transport distance (saving space in the work area). The structure of the shifter 15 is not particularly limited as long as it can change the trajectory while holding the workpiece W. Heating means such as a cartridge heater may also be installed at the location where the shifter 15 is provided.

Furthermore, in order to perform the necessary control management for the high-temperature furnace 1, a memory unit for storing the control program, a display unit (output unit) for displaying and outputting the temperature and disconnections at each location, an operation unit (input unit) for operating each component, etc. can also be provided (see Figure 1).

[Method and use of high-temperature furnace 1]
The dimensions of each station 4 and the type of the first heater 5 are adjusted depending on the material and dimensions of the workpiece W, the target heating temperature, etc. Needless to say, the size and positional relationship of each member of the high-temperature furnace 1 should be appropriately adjusted according to the size of the workpiece W and the station 4.

The high-temperature furnace 1 of the present disclosure can be used to heat the workpiece W. The high-temperature furnace 1 can heat the workpiece W to a desired temperature using the hot air generator 3, the first heater 5, and the second heater 6. According to the high-temperature furnace 1 of the present disclosure, when it is desired to heat the workpiece W to, for example, 200°C before a subsequent process, the workpiece W can be heated (kept warm) to a temperature within the range of 170°C to 230°C, preferably within the range of 190°C to 210°C.

The heating (heat retention) temperature can also be set in the high-temperature furnace 1 for the purpose of performing heat treatment such as tempering.

[motion]
(Normal mode)
In order to heat the workpiece W, as described above, the first control unit 11 controls the operation of the high-temperature furnace 1, and the second control unit 12 controls the temperature of the high-temperature furnace 1. More specifically, the first control unit 11 controls, for example, a conveying means for passing the workpiece W through the multiple stations 4. The second control unit 12 controls the hot air generator 3, the first heater 5, the second heater 6, etc., so that the workpiece W is heated to a desired temperature.

The first control unit 11 can also control the transport speed (transport interval) of the workpiece W. As described above, in the high-temperature furnace 1, the workpiece W can be efficiently heated by three types of heaters, so the transport speed within the high-temperature furnace 1 can be increased and the heating time can be shortened.

Whether the workpiece W has reached the desired temperature may be checked at any point in the high-temperature furnace 1 (station 4, shifter 15, etc.). For ease of checking the temperature, it is preferable to check at the turning point of the transport path (shifter 15). If the workpiece W has not yet reached the desired temperature before it is discharged from the high-temperature furnace 1, the heating temperature of the hot air generator 3, etc. can be increased. Also, if the workpiece W is at a high temperature for a long time, it will be affected by heat (thermal hardening, distortion, oxidation, discoloration), so it is preferable to have the workpiece W reach the target heating temperature at the point where it is discharged from the high-temperature furnace 1.

(Keep warm mode)
As described above, the high-temperature furnace 1 of the present disclosure is used to heat the workpieces W, and can be incorporated into a series of manufacturing lines. It is therefore possible that the high-temperature furnace 1 (station 4) may be stopped due to a cause before or after the manufacturing line other than the high-temperature furnace 1. In this case, the first control unit 11 stops the conveying means and sets the high-temperature furnace 1 to a heat retention mode. After the shutter 2b is closed, the second control unit 12 can maintain the temperature in the high-temperature furnace 1 by the hot air generator 3 based on the space temperature and the plate temperature. In the heat retention mode, all the workpieces W may be set to move into station 4 based on the space temperature and the plate temperature (the workpieces W are not left in the shifter 15).

The high-temperature furnace 1 of this embodiment, configured as described above, is provided with a hot air generator 3 for heating and circulating the atmosphere within the high-temperature furnace 1, and multiple stations 4 on which the workpiece W is placed and moved. Each station 4 includes a first heater 5 for heating the workpiece W from the left and right, and a second heater 6 for heating the workpiece W from above and below.

The high-temperature furnace 1 of this embodiment has the advantage that the three types of heaters can be used to achieve uniform heating throughout the high-temperature furnace 1 and to shorten the heating process. Furthermore, by heating within the station 4 as described above, there is also the advantage that heat is not lost compared to heating on a simple belt conveyor.

In addition, according to the high-temperature furnace 1 of this embodiment, the first heater 5 may be a ceramic heater, and the second heater 6 may be a cartridge heater. Conventionally, in continuous furnaces, it is common to heat the workpiece W, which is the object to be heated, by hot air or radiant heat. Although it is possible to heat the object to be heated to, for example, 600°C by using a cartridge heater, a furnace is intended to heat metal to high temperatures of 300°C or higher, glass to 700°C, and ceramics to 1000 to 2,000°C or higher, and cartridge heaters are rarely used due to their capabilities. In contrast, according to the high-temperature furnace 1 of this embodiment, in addition to the hot air generator 3, the cartridge heater 6 and ceramic heater 5 are used to heat the workpiece W from above, below, left and right, making it possible to heat the workpiece W uniformly, which is particularly suitable when precise heat treatment is required.

In addition, according to the high-temperature furnace 1 of this embodiment, as described above, one of the second heaters 6 (6a, 6b) may contact and heat the workpiece W. Furthermore, the second heaters 6 (6a, 6b) may contact and heat the workpiece W from above and below. This allows for more efficient heat transfer, leading to more efficient heating, shorter heating time, and more stable temperature. For example, when the second heater 6a is used alone to contact and heat the workpiece W, this can also be applied to a belt conveyor used as a means for transporting the workpiece W. In other words, by lowering the second heater 6a directly above the workpiece W transported to station 4 by the belt conveyor and heating it in contact with it, intermittent heating is possible within station 4, and heating variations can be suppressed.

In addition, according to the high-temperature furnace 1 of this embodiment, the station 4 includes a placement section 7, and the placement section 7 may move the workpiece W forward to enable cyclic operation of movement at each station 4. The cyclic operation in which heating and movement are repeated enables intermittent heating and suppresses uneven heating.

The high-temperature furnace 1 of this embodiment may further include a first control unit 11 that controls the operation of the high-temperature furnace 1, and a second control unit 12 that controls the temperature of the high-temperature furnace 1. By providing two control units that perform different controls, temperature management can be performed centrally.

In particular, by using a PLC as described above as the second control unit 12, multiple temperature sensors, multiple first heaters 5, and multiple second heaters 6 can be combined in various ways to realize centralized temperature control (n:n control). For example, since it is possible to control one heater by looking at the values of multiple temperature sensors, precise temperature control can be performed at each station 4 or at each heater position. A thermocouple 13 can be suitably used as a temperature detection means for temperature control.

In addition, according to the high-temperature furnace 1 of this embodiment, when the current sensor 14 detects a break in the power line of the first heater 5 or the second heater 6, the second control unit 12 may stop the first heater 5 and the second heater 6. In this way, the safety of the high-temperature furnace 1 can be ensured.

In addition, according to the high-temperature furnace 1 of this embodiment, when it is determined that the cycle operation cannot be performed, a heat retention mode may be set to keep the workpiece W warm. In this way, even if a problem occurs on the production line, heating can be continued without using special heat retention materials. As described above, various heat retention modes can be set in advance.

The high-temperature furnace 1 of this embodiment may further include an air cylinder 10 on which the second heater 6 is mounted, and may be configured to move the workpiece W up and down by the air cylinder 10. For example, by moving the second heater 6 (6a, 6b) by the thrust of the air cylinder 10, it is possible to accommodate changes in the thickness, volume, etc. of the workpiece W to be heated (i.e., the workpiece W can be contacted and uniformly heated regardless of the thickness, volume, etc. of the workpiece W). In addition, the second heater 6 can be in uniform contact with the workpiece W without excessively pressurizing it. In particular, if the size of the workpiece to be heated is large, there is a possibility that only the outside will be overheated. However, even if the high-temperature furnace 1 of the present disclosure does not have a cooling system such as a chiller, the upper and lower second heaters 6a, 6b can be brought into contact with the workpiece W or avoided, thereby making it possible to heat and cool the workpiece W (temperature adjustment).

The high-temperature furnace 1 of this embodiment may further include a shifter 15 that changes the trajectory of movement of the workpiece W. In this way, the transport path of the high-temperature furnace 1 and the workpiece W is not limited to a linear shape, but can be designed to be U-shaped as in the examples of Figures 1 and 2, or can be designed in various shapes as appropriate according to the area and installation location of a work area such as a factory.

The high-temperature furnace 1 according to this embodiment is not limited to the above-mentioned configuration, and various modifications can be made.

Conventionally, when stacked workpieces are heated, there is a problem that the heat conduction is poor due to the air layer between the workpieces, resulting in temperature unevenness. In contrast, according to the high-temperature furnace 1 of the present disclosure, it is possible to suppress the heating variation even for stacked workpieces W by using three types of heaters and intermittent heating in each station 4. In addition, according to the high-temperature furnace 1 of the present disclosure, it is also possible to heat one workpiece. In this case, as described above, the height of the second heater 6 can be adjusted by the air cylinder 10 to match the height of the workpiece W. Also, for example, even if the upper second heater 6a is fixed and its height cannot be adjusted, it is also possible to adjust the position of the workpiece W to match the first heater 5 by the lower second heater 6b. For example, it is also possible to match the center position of the workpiece W to the position of the hot spot of the first heater 5 (for example, the position where the heat amount is highest in the center part of the first heater 5 in FIG. 3). In this way, the shape, size, material (for example, glass, ceramic), etc. of the workpiece to which the high-temperature furnace 1 of the present disclosure can be applied are not particularly limited.

In the example shown in FIG. 3, station 4 is in a semi-sealed state that allows hot air from hot air generator 3 to enter, but each station 4 may be sealed by using an insulating member that can be opened and closed.

Reference Signs List 1 High-temperature furnace 2a Cover 2b Shutter 3 Hot air generator 4 Station 5 (5a, b) First heater 6 (6a, b) Second heater 7 Placement section 8 Jig 9 Heater plate 10 Air cylinder 11 First control section 12 Second control section 13 Thermocouple 14 Current sensor 15 Shifter 16 Heat insulating material W Workpiece

Claims (11)

A hot air generator for heating and circulating the atmosphere inside the furnace;
A plurality of stations that share a transport path for disk-shaped metal workpieces and move the workpieces while placing them thereon ;
A jig having a base on which the workpiece is placed and a support that passes through an opening in the center of the workpiece;
Equipped with
Each of the stations includes a first heater for heating the workpiece from the left and right sides and a second heater for heating the workpiece from above and below,
The second heater also heats the workpiece from the inside through the jig. The high temperature furnace of claim 1 , wherein one of the second heaters contacts and heats the workpiece . The high-temperature furnace according to claim 1 , wherein the second heater heats the workpiece by contacting the workpiece from above and below. The high-temperature furnace according to any one of claims 1 to 3, wherein the first heater is a ceramic heater and the second heater is a cartridge heater. The station includes a placement portion,
The high temperature furnace according to claim 1 , wherein the placement section moves the workpiece forward to enable a cyclical movement of the workpiece through each of the stations. A first control unit that controls the operation of the high-temperature furnace;
A second control unit that controls the temperature of the high-temperature furnace;
The high temperature furnace of claim 1 further comprising: The high-temperature furnace according to claim 6, wherein the second control unit is a PLC and enables centralized temperature control by various combinations of multiple temperature sensors, multiple first heaters, and multiple second heaters. The high-temperature furnace according to claim 6, wherein the second control unit stops the first heater and the second heater when a current sensor detects a break in the power line of the first heater or the second heater. 6. The high-temperature furnace according to claim 5, further comprising a heat-retention mode for retaining the workpiece when it is determined that the cycle operation cannot be performed. The heater further includes an air cylinder on which the second heater is mounted,
2. The high temperature furnace according to claim 1, wherein the workpiece is moved up and down by the air cylinder. The high-temperature furnace according to claim 1 , further comprising a shifter for changing a trajectory of movement of the workpiece.

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