Heat treatment system and atmosphere replacement structure provided in heat treatment furnace

Abstract

A heat treatment system is provided with a first supply device, a first heat treatment furnace, a first recovery device, a second supply device, a second heat treatment furnace, and a second recovery device. The first heat treatment furnace is provided with: an input port disposed in the vicinity of the first supply device; an output port; a heat treatment unit; and the first conveying device conveys the saggar in the first direction from the input port to the output port of the first heat treatment furnace. The second heat treatment furnace is provided with: an input port disposed in the vicinity of the second supply device; an output port; a heat treatment unit; and the second conveying device conveys the saggar in a second direction opposite to the first direction from the input port to the output port of the second heat treatment furnace. Each of the first heat treatment furnace and the second heat treatment furnace is further provided with a replacement part which is disposed between the heat treatment part and the output port and which separates the heat treatment part from the outside of the output port. The replacement part is provided with an openable and closable door formed of a thermal insulation material between the heat treatment part and the output port.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a technology for heat treating a workpiece. Background Art

[0002] Sometimes a heat treatment furnace (such as a roller kiln, a push plate kiln, etc.) is used to heat treat the object to be treated. Usually, in a heat treatment furnace, it is required to improve productivity and reduce the amount of atmosphere gas used. For example, a heat treatment system is disclosed in Patent Document 1, which includes: a heat treatment furnace for conveying the object to be treated in a forward direction, and a heat treatment furnace for conveying the object to be treated in a reverse direction. In the heat treatment system of Patent Document 1, the object to be treated is stored in a sagger and conveyed in the heat treatment furnace, and is heat treated during the period when the sagger is conveyed in the heat treatment furnace. The sagger is repeatedly used for heat treatment of the object to be treated. In the heat treatment system of Patent Document 1, the output port of the heat treatment furnace for conveying the object to be treated in the forward direction is arranged near the input port of the heat treatment furnace for conveying the object to be treated in the reverse direction, and the output port of the heat treatment furnace for conveying the object to be treated in the reverse direction is arranged near the input port of the heat treatment furnace for conveying the object to be treated in the forward direction. Thus, the sagger can be kept in a high temperature state and imported into the next heat treatment furnace. Therefore, the time for heating the sagger is shortened and the length of the heat treatment furnace is shortened. Therefore, the usage amount of the atmospheric gas in the heat treatment furnace is reduced.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2020-85367 Summary of the invention

[0006] Usually, a displacement part for displacing the atmosphere between the inside of the heat treatment furnace (i.e., the heat treatment part for heat treatment of the object to be treated) and the outside of the heat treatment furnace is provided on the output side of the heat treatment furnace. In the displacement part, a door that can be opened and closed is provided at the boundary with the heat treatment part and the boundary with the outside of the heat treatment furnace. When the displacement part displaces the atmosphere, it is necessary to utilize the door to seal the displacement part well. However, in the heat treatment system of patent document 1, in order to keep the sagger at a high temperature and input it into the next heat treatment furnace, the sagger is output from the heat treatment furnace in a high temperature state. Therefore, the temperature in the displacement part also becomes a high temperature, and it is difficult to ensure the sealing of the displacement part realized by the door.

[0007] This specification discloses a technology capable of taking a sagger out of a heat treatment furnace while maintaining the sagger at a high temperature.

[0008] In the first scheme of the technology disclosed in this specification, the heat treatment system includes: a first supply device, a first heat treatment furnace, a first recovery device, a second supply device, a second heat treatment furnace, and a second recovery device. The first supply device is arranged near the second recovery device, and supplies the processed object to the sagger transported from the second recovery device. The first heat treatment furnace includes: an input port, which is arranged near the first supply device, for the sagger supplied with the processed object by the first supply device to be input; an output port, which is for the sagger supplied with the input; a heat treatment section, which is arranged between the input port and the output port of the first heat treatment furnace, and performs heat treatment on the processed object supplied to the sagger during the period when the sagger is transported from the input port of the first heat treatment furnace to the output port; and a first conveying device, which conveys the sagger in a first direction from the input port of the first heat treatment furnace toward the output port. The first recovery device is arranged near the output port of the first heat treatment furnace, and recovers the processed object heat-treated by the first heat treatment furnace from the sagger. The second supply device is arranged near the first recovery device, and supplies new processed objects to the sagger from which the processed objects have been recovered by the first recovery device. The second heat treatment furnace comprises: an input port, which is arranged near the second supply device, and is used to input the sagger supplied with processed objects by the second supply device; an output port, and is used to output the input sagger; a heat treatment section, which is arranged between the input port and the output port of the second heat treatment furnace, and performs heat treatment on the processed objects supplied to the sagger during the period when the sagger is transported from the input port of the second heat treatment furnace to the output port; and a second conveying device, which conveys the sagger from the input port to the output port of the second heat treatment furnace in a second direction opposite to the first direction. The second recovery device is arranged near the output port of the second heat treatment furnace, and recovers the processed objects that have been heat-treated by the second heat treatment furnace from the sagger. The first heat treatment furnace and the second heat treatment furnace are also respectively provided with a replacement section, which is arranged between the heat treatment section of the heat treatment furnace and the output port of the heat treatment furnace, and isolates the heat treatment section of the heat treatment furnace from the outside of the output port of the heat treatment furnace. The replacement part includes openable and closable doors formed of a heat insulating material between the replacement part and the heat treatment part of the heat treatment furnace and between the replacement part and the outlet of the heat treatment furnace.

[0009] In the above-mentioned heat treatment system, a door formed of a heat insulating material is provided at the entrance and exit of the replacement part. By forming the door with a heat insulating material, the heat resistance of the door can be ensured, thereby suppressing the thermal deformation of the door. Thus, the heat treatment part and the outside of the furnace can be isolated by the replacement part, ensuring the airtightness (sealing) of the heat treatment part. Therefore, the sagger can be transported to the replacement part in a high-temperature state, and the sagger can be output to the outside of the heat treatment furnace in a high-temperature state.

[0010] In addition, the atmosphere replacement structure disclosed in this specification maintains the atmosphere of the internal space of the heat treatment part in the heat treatment furnace, and the heat treatment furnace includes: an input port, at which a sagger supplied with a processed object is input into the furnace; a heat treatment part, which performs heat treatment on the processed object supplied to the sagger input from the input port; an output port, at which the above-mentioned sagger supplied with the processed object that has been heat-treated by the heat treatment part is output to the outside of the furnace; and a first conveying device, which conveys the sagger from the input port to the output port. The atmosphere replacement structure includes: a replacement chamber, which is arranged between the heat treatment part and the output port; a first door, which is arranged between the replacement chamber and the heat treatment part; and a second door, which is arranged between the replacement chamber and the output port. The first door and the second door are respectively formed of a heat insulating material.

[0011] In the above-mentioned atmosphere replacement structure, a first door formed of a heat insulating material is provided at the inlet of the replacement chamber, and a second door formed of a heat insulating material is provided at the outlet of the replacement chamber. Therefore, the same effect as the above-mentioned heat treatment system can be exerted. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a plan view showing a schematic structure of a heat treatment system according to this embodiment.

[0013] Figure 2 It is a diagram showing a schematic configuration of a first heat treatment furnace, and is a longitudinal cross-sectional view when the heat treatment furnace is cut along a plane parallel to the conveying direction of the workpiece.

[0014] Figure 3 yes Figure 2 Cross-sectional view at line III-III.

[0015] Figure 4 It is a block diagram showing the configuration of a control system of the first heat treatment furnace.

[0016] Figure 5 It is a side view showing the schematic structure of an output side atmosphere replacement structure provided on the output side of the heat treatment section.

[0017] Figure 6 It is a front view showing the structure of the door.

[0018] Figure 7 yes Figure 6 Cross-sectional view at line VII-VII.

[0019] Figure 8 1 and 10 are side views showing the structure of a pressing device, wherein (a) shows a state where the door is pressed by the pressing device, and (b) shows a state where the door is not pressed by the pressing device.

[0020] Fig. 9This is a front view showing the structure of the door, chain, and shaft. DETAILED DESCRIPTION

[0021] The main features of the embodiments described below are listed in advance. It should be noted that the technical elements described below are independent technical elements, which can exert technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of application.

[0022] The second scheme of the technology disclosed in this specification is based on the above-mentioned first scheme, and the first heat treatment furnace and the second heat treatment furnace can be further equipped with: a contact surface, which is arranged between at least one door of the doors arranged in the replacement part and the heat treatment part, and abuts against the entire outer periphery of the door when the door is closed; and a pressing device, which is arranged outside the replacement part and presses the door toward the contact surface when the door is closed. According to this structure, the door and the heat treatment part can be sealed by using the pressing device. Therefore, the airtightness of the heat treatment part realized by the door can be improved, so that the atmosphere of the heat treatment part can be maintained.

[0023] The third solution of the technology disclosed in this specification is based on the above-mentioned second solution, and the abutting surface can have a sealing part, which seals between the door and the abutting surface. The sealing part can be formed by a fiber-based sealing material. According to this structure, the heat resistance of the sealing part can be ensured.

[0024] The fourth scheme of the technology disclosed in this specification is based on the second or third scheme mentioned above, and the pressing device can include: a pressing part that can abut against the door; a cylinder that is arranged to be closer to the output port side than the pressing part and presses the pressing part; and a connecting part that connects the pressing part and the cylinder. The pressing part and the connecting part can be formed of a heat-resistant material. According to this structure, by connecting the cylinder and the pressing part with the help of the connecting part, the cylinder can be set at a position away from the door at a high temperature. Therefore, it is possible to suppress the thermal influence on the cylinder.

[0025] A fifth solution of the technology disclosed in this specification is based on the fourth solution described above, wherein the pressing part can be formed of a ceramic material. The pressing part abuts against a door at a high temperature. By making the pressing part of ceramic, the heat resistance of the pressing part can be improved.

[0026] The sixth solution of the technology disclosed in this specification is based on the fourth or fifth solution described above, and the first heat treatment furnace and the second heat treatment furnace can each further include a chain, which is connected to the upper end of at least one of the doors arranged in the replacement part to support the door. According to this structure, the chain is used to make the door in a free hanging state. Therefore, even if the door is thermally deformed, the sealing performance when the door is pressed by the pressing device can be ensured.

[0027] The seventh scheme of the technology disclosed in this specification is based on the above-mentioned sixth scheme, and the first heat treatment furnace and the second heat treatment furnace can be further equipped with: an axis, which is used to roll up the chain by rotating the axis in a first direction, and the chain is released by rotating the axis in a second direction opposite to the first direction; and a driving device, which rotates the axis. The axis can be arranged above the chain in a direction with the axis horizontal and orthogonal to the conveying direction. The door can move upward by rolling up the chain with the axis, and move downward by releasing the chain with the axis. According to this structure, the axis that rolls up or releases the chain is arranged in a direction (lateral) with the axis horizontal and orthogonal to the conveying direction. In addition, one end of the chain is connected to the door, and the other end of the chain is connected to the axis arranged outside the replacement part. Therefore, when the door is open, the space in the heat treatment part is connected to the space outside the replacement part (heat treatment furnace) via the configuration space of the chain. In order to ensure the airtightness of the heat treatment part, it is preferred that the configuration space of the chain is sealed relative to the space outside the replacement part. By adopting a structure in which the chain is rolled up on an axis, the axis as the driving part only performs a rotational motion around its axis, and therefore, the area of ​​the portion that needs to be sealed can be reduced. On the other hand, unlike the above structure, in the case of a structure in which a cylinder is used to move the chain up and down, for example, the cylinder as the driving part needs to have a stroke length corresponding to the size of the door, and the area of ​​the portion that needs to be sealed becomes larger. Therefore, according to the above structure, the area of ​​the portion that needs to be sealed can be reduced.

[0028] The eighth solution of the technology disclosed in this specification is based on the seventh solution described above, wherein the door can be configured such that: the door is opened by moving it downward. The upper part of the door is easily affected by heat. By moving the door downward to open, the door is not easily affected by heat when it is open.

[0029] The ninth scheme of the technology disclosed in this specification is based on the above-mentioned first scheme, and the first heat treatment furnace and the second heat treatment furnace can each further have an input side replacement part, which is arranged between the heat treatment part of the heat treatment furnace and the input port of the heat treatment furnace, and isolates the heat treatment part of the heat treatment furnace from the outside of the input port of the heat treatment furnace. The input side replacement part can be provided with a door that can be opened and closed formed by a heat insulating material between the heat treatment part of the heat treatment furnace and the input port of the heat treatment furnace. According to this structure, in addition to the output side of the heat treatment furnace, a replacement part is also provided on the input side of the heat treatment furnace. Thus, replacement parts are provided on both the input side and the output side of the heat treatment furnace, and the heat treatment part and the outside of the heat treatment furnace can be isolated by replacement parts on both the input side and the output side of the heat treatment furnace. In addition, in the input side replacement part, similarly, doors formed by heat insulating materials are provided at the entrance and the exit, so that the heat resistance of the door can be ensured and the thermal deformation of the door can be suppressed. Therefore, the high-temperature sagger can be transported from the outside to the input-side replacement part, and the high-temperature sagger transported to the input-side replacement part can be imported into the heat treatment furnace.

[0030] Example

[0031] The heat treatment system 1 of this embodiment will be described with reference to the accompanying drawings. Figure 1 As shown, the heat treatment system 1 includes: a first supply device 80a, a first heat treatment furnace 10a, a first recovery device 82a, a second supply device 80b, a second heat treatment furnace 10b, and a second recovery device 82b. The heat treatment system 1 stores the Figure 2 ) is subjected to heat treatment. In the present embodiment, the object to be treated contained in the sagger 2 is a powder of a positive electrode material of a lithium-ion battery. In the heat treatment system 1 of the present embodiment, the sagger 2 is configured to circulate between a first supply device 80a, a first heat treatment furnace 10a, a first recovery device 82a, a second supply device 80b, a second heat treatment furnace 10b, and a second recovery device 82b. During the period when the sagger 2 is transported in the first heat treatment furnace 10a or the second heat treatment furnace 10b, the object to be treated is subjected to heat treatment.

[0032] First, the first supply device 80a and the second supply device 80b are described. The first supply device 80a is arranged between the second recovery device 82b and the first heat treatment furnace 10a (in detail, the input port 20a of the first heat treatment furnace 10a). The first supply device 80a supplies a new object to be processed to the empty sagger 2 from which the object to be processed is recovered by the second recovery device 82b. The second supply device 80b is arranged between the first recovery device 82a and the second heat treatment furnace 10b (in detail, the input port 20b of the second heat treatment furnace 10b). The second supply device 80b supplies a new object to be processed to the empty sagger 2 from which the object to be processed is recovered by the first recovery device 82a. The first supply device 80a and the second supply device 80b have the same structure. Therefore, the following describes the first supply device 80a.

[0033] The first supply device 80a is a device for supplying a processed object (i.e., powder) into the sagger 2. It should be noted that the first supply device 80a is configured to supply powder into the sagger 2, and the specific structure is not particularly limited. For example, the first supply device 80a includes a supply portion and a flattening portion. The supply portion is configured to supply powder to the inside of the sagger 2. Specifically, the supply portion includes a supply port for causing the powder to fall from the upper side of the sagger 2 to the inside of the sagger 2. The supply port is configured to be located above the center of the sagger 2 when the sagger 2 is arranged in the supply portion. The supply portion is provided with a positioning device, which positions the sagger 2 transported to the supply portion so that it is located below the supply port. The contact surface between the positioning device and the sagger 2 is formed by a ceramic material. Thus, the heat resistance of the positioning device can be ensured, so that the high-temperature sagger 2 can be positioned in the supply portion. It should be noted that a plurality of supply ports can be arranged in the supply portion. The supply unit supplies powder into the sagger 2 by causing the powder to fall from above. Therefore, when the powder is supplied to the sagger 2 by the supply unit, the upper surface of the powder in the sagger 2 is raised at a position below the supply port. The leveling unit leveled the powder supplied into the sagger 2 by the supply unit. Specifically, the leveling unit is configured to level the upper surface of the powder by pressing the upper surface of the powder in the sagger 2 with the side of a flat plate. By leveling the upper surface of the powder by the leveling unit, the upper surface of the powder stored in the sagger 2 becomes a substantially horizontal plane. In addition, regarding the supply device 80a, a heat insulating material for heat insulation is provided on a component (frame, etc.) located above the sagger 2. Thus, the supply device 80a can ensure the heat resistance of the sagger 2 at high temperatures, thereby being able to supply powder to the sagger 2 at high temperatures.

[0034] Next, the first heat treatment furnace 10 a and the second heat treatment furnace 10 b will be described. The first heat treatment furnace 10 a and the second heat treatment furnace 10 b perform heat treatment on the object to be treated in the sagger 2 .

[0035] like Figure 2 to Figure 4As shown, the first heat treatment furnace 10a includes: a heat treatment section 12, an input side atmosphere replacement structure 40, an output side atmosphere replacement structure 42, a conveying device (24, 26), and a control device 28. The first heat treatment furnace 10a performs heat treatment on the object to be treated stored in the sagger 2 while the sagger 2 is conveyed in the heat treatment section 12 by the conveying device (24, 26).

[0036] The heat treatment section 12 has a substantially rectangular parallelepiped shape and is surrounded by a top wall 14a, a bottom wall 14b, side walls 14c and 14d, and two doors 48 described below. Figure 2 As shown in FIG. 1 , the top wall 14a is arranged parallel to the bottom wall 14b (ie, parallel to the XY plane). Figure 3 As shown, the side walls 14c and 14d are arranged parallel to the conveying direction and perpendicular to the top wall 14a and the bottom wall 14b (that is, parallel to the XZ plane). Figure 2 As shown, the entrance of the heat treatment section 12 is separated from the input side atmosphere replacement structure 40 by one of the two doors 48, and the outlet of the heat treatment section 12 is separated from the output side atmosphere replacement structure 42 by the other door 48. A plurality of heaters 16a, 16b and a plurality of conveying rollers 24 are arranged in the heat treatment section 12. The heater 16a is arranged at a position above the conveying roller 24 along the conveying direction at a predetermined interval, and the heater 16b is arranged at a position below the conveying roller 24 along the conveying direction at a predetermined interval. The heaters 16a and 16b generate heat, thereby heating the space 18 in the heat treatment section 12, and heating the processed object stored in the sagger 2.

[0037] The input side atmosphere replacement structure 40 is disposed adjacent to the input side of the heat treatment unit 12, and the output side atmosphere replacement structure 42 is disposed adjacent to the output side of the heat treatment unit 12. It should be noted that the configurations of the input side atmosphere replacement structure 40 and the output side atmosphere replacement structure 42 are described in detail below.

[0038] The conveying device (24, 26) includes a plurality of conveying rollers 24 and a roller driving device 26. The conveying rollers 24 convey the sagger 2. The conveying device (24, 26) conveys the sagger 2 from the input port 20a of the first heat treatment furnace 10a to the input side atmosphere replacement structure 40, and then passes through the input side atmosphere replacement structure 40 to convey it to the heat treatment section 12. In addition, the conveying device (24, 26) conveys the sagger 2 from the heat treatment section 12 to the output side atmosphere replacement structure 42, passes through the output side atmosphere replacement structure 42, and conveys it to the outside from the output port 22a of the first heat treatment furnace 10a. In the first heat treatment furnace 10a, the conveying device (24, 26) conveys the sagger 2 to the +X direction.

[0039] The conveying roller 24 is cylindrical, and its axis extends in a direction orthogonal to the conveying direction (i.e., the Y direction). The plurality of conveying rollers 24 all have the same diameter and are arranged at equal intervals along the conveying direction at a certain pitch. The conveying roller 24 is supported so as to be rotatable around its axis, and is rotated by the driving force transmitted by the roller driving device 26. The roller driving device 26 is a driving device (e.g., a motor) that drives the conveying roller 24. The roller driving device 26 is connected to the conveying roller 24 by means of a power transmission mechanism. When the driving force of the roller driving device 26 is transmitted to the conveying roller 24 via the power transmission mechanism (e.g., a mechanism based on sprocket teeth and a chain), the conveying roller 24 rotates.

[0040] like Figure 3 As shown, in this embodiment, a plurality of saggers 2 are overlapped in the vertical direction and in a direction orthogonal to the conveying direction ( Figure 3 The conveying device (24, 26) is configured to align the multiple saggers 2 arranged side by side in the Y direction when conveying the saggers 2 from the input side atmosphere replacement structure 40 to the heat treatment section 12, and simultaneously convey the multiple saggers 2 arranged side by side in the Y direction to the heat treatment section 12. Similarly, the conveying device (24, 26) is configured to align the multiple saggers 2 arranged side by side in the Y direction when conveying the saggers 2 from the heat treatment section 12 to the output side atmosphere replacement structure 42, and simultaneously convey the multiple saggers 2 arranged side by side in the Y direction to the output side atmosphere replacement structure 42. It should be noted that, hereinafter, the configuration of the conveying device (24, 26) aligning the multiple saggers 2 arranged side by side in the Y direction will be described.

[0041] The control device 28 is composed of a computer including a CPU, a ROM, and a RAM, for example. Figure 4 As shown, the control device 28 is connected to the heaters 16a, 16b, the roller driving device 26, the door pressing device 56 (described later), and the door lifting device 74 (described later), and controls the heaters 16a, 16b, the roller driving device 26, the door pressing device 56, and the door lifting device 74.

[0042] like Figure 1As shown, the second heat treatment furnace 10b is arranged in parallel with the first heat treatment furnace 10a at an interval in the Y direction. The second heat treatment furnace 10b is arranged so that the direction of conveying the sagger 2 is opposite to that of the first heat treatment furnace 10a. That is, the input port 20b of the second heat treatment furnace 10b is arranged near the output port 22a of the first heat treatment furnace 10a, and the output port 22b of the second heat treatment furnace 10b is arranged near the input port 20a of the first heat treatment furnace 10a. As a result, the conveying direction of the sagger 2 in the first heat treatment furnace 10a (from the -X direction to the +X direction) and the conveying direction of the sagger 2 in the second heat treatment furnace 10b (from the +X direction to the -X direction) are opposite. It should be noted that, as described above, the second heat treatment furnace 10b has substantially the same structure as the first heat treatment furnace 10a, and therefore, a detailed description of the structure is omitted.

[0043] Next, the first recovery device 82a and the second recovery device 82b are described. The first recovery device 82a is arranged between the first heat treatment furnace 10a (in detail, the output port 22a of the first heat treatment furnace 10a) and the second supply device 80b. The first recovery device 82a recovers the processed object that has been heat-treated by the first heat treatment furnace 10a from the sagger 2. The second recovery device 82b is arranged between the second heat treatment furnace 10b (in detail, the output port 22b of the second heat treatment furnace 10b) and the first supply device 80a. The second recovery device 82b recovers the processed object that has been heat-treated by the second heat treatment furnace 10b from the sagger 2. The first recovery device 82a and the second recovery device 82b have the same structure. Therefore, the following describes the first recovery device 82a.

[0044] The first recovery device 82a is a device for recovering the treated object (i.e., powder) heat-treated by the first heat treatment furnace 10a from the sagger 2. It should be noted that the first recovery device 82a is configured to recover the powder from the sagger 2, and the specific structure is not particularly limited. For example, the first recovery device 82a includes: a reversing recovery unit, which reversals the sagger 2 in the up-down direction for recovery; and an air recovery unit, which uses air to peel off the treated object (powder in this embodiment) attached to the surface of the sagger 2 for recovery. The reversing recovery unit moves the powder in the sagger 2 to a recovery container by reversing the sagger 2 in the up-down direction. As a result, almost all of the powder contained in the sagger 2 is moved to the recovery container. The reversing recovery unit includes an operating unit for reversing the sagger 2, and the operating unit is formed of a ceramic material. The operating unit is in contact with the sagger 2. By forming the operating unit from a ceramic material, the heat resistance of the operating unit can be ensured, and the operating unit can grasp the high-temperature sagger 2. Afterwards, the reversing recovery unit reverses the sagger 2 again in the up-down direction and returns to its original orientation. The air recovery unit is used after the powder in the sagger 2 is recovered by the overturning recovery unit. The air recovery unit blows air to the inner surface of the sagger 2 while sucking the air in the sagger 2. By blowing air to the inner surface of the sagger 2, the powder attached to the inner surface of the sagger 2 is peeled off from the inner surface. If the air in the sagger 2 is sucked while blowing air to the inner surface of the sagger 2, the powder peeled off from the inner surface of the sagger 2 is sucked together with the air. Thus, the powder remaining on the inner surface of the sagger 2 is recovered, and the recovery rate of the powder increases. It should be noted that in the above-mentioned example, the first recovery device 82a is equipped with an air recovery unit, but is not limited to this structure. For example, it can be configured as follows: the powder remaining on the inner surface of the sagger 2 is peeled off and recovered by using a rotating brush.

[0045] As described above, the sagger 2 is circulated and transported between the first supply device 80a, the first heat treatment furnace 10a, the first recovery device 82a, the second supply device 80b, the second heat treatment furnace 10b, and the second recovery device 82b. Roller conveyors are respectively arranged between the first supply device 80a, the first heat treatment furnace 10a, the first recovery device 82a, the second supply device 80b, the second heat treatment furnace 10b, and the second recovery device 82b to transport the sagger 2. It should be noted that the sagger 2 can be circulated and transported between the first supply device 80a, the first heat treatment furnace 10a, the first recovery device 82a, the second supply device 80b, the second heat treatment furnace 10b, and the second recovery device 82b, and other conveying devices other than the roller conveyor (such as a belt conveyor, etc.) can be used.

[0046] In this embodiment, the first heat treatment furnace 10a and the second heat treatment furnace 10b are provided in such a manner that the conveying direction of the sagger 2 of the first heat treatment furnace 10a and the conveying direction of the sagger 2 of the second heat treatment furnace 10b face opposite directions. That is, the distance between the output port 22a of the first heat treatment furnace 10a and the input port 20b of the second heat treatment furnace 10b becomes closer, and the distance between the output port 22b of the second heat treatment furnace 10b and the input port 20a of the first heat treatment furnace 10a also becomes closer. Thus, the sagger 2 used for heat treatment in the first heat treatment furnace 10a can be kept at a high temperature and input to the second heat treatment furnace 10b. Similarly, the sagger 2 used for heat treatment in the second heat treatment furnace 10b can also be kept at a high temperature and input to the first heat treatment furnace 10a. Therefore, the time for heating the sagger 2 in the heat treatment furnaces 10a and 10b can be shortened, so the length of the heat treatment section 12 of the first heat treatment furnace 10a and the second heat treatment furnace 10b can be shortened, thereby reducing the energy required for heating the object to be treated. In addition, since the sagger 2 is kept at a high temperature and output from the first heat treatment furnace 10a or the second heat treatment furnace 10b, it is not necessary to set a cooling unit on the output side of the heat treatment unit 12 of the first heat treatment furnace 10a and the second heat treatment furnace 10b, or even if a cooling unit is provided, since the sagger 2 does not need to be cooled to a lower temperature, the length of the cooling unit can be shortened. For example, in the previous heat treatment furnace, the sagger 2 is cooled to about 200 degrees and output from the heat treatment furnace, but in the heat treatment system 1 of the present embodiment, the sagger 2 can be cooled to 400 degrees and output from the first heat treatment furnace 10a or the second heat treatment furnace 10b. In this way, the length of the first heat treatment furnace 10a and the second heat treatment furnace 10b can be shortened, so the usage of the atmosphere gas in the first heat treatment furnace 10a and the second heat treatment furnace 10b can be reduced.

[0047] Here, the input side atmosphere replacement structure 40 and the output side atmosphere replacement structure 42 are described. It should be noted that, as described above, the first heat treatment furnace 10a and the second heat treatment furnace 10b are arranged in opposite directions of conveying of the sagger 2, and other than that, they have the same structure. Hereinafter, the input side atmosphere replacement structure 40 and the output side atmosphere replacement structure 42 of the first heat treatment furnace 10a are described. The input side atmosphere replacement structure 40 is arranged between the input port 20a of the first heat treatment furnace 10a and the heat treatment part 12, and the output side atmosphere replacement structure 42 is arranged between the heat treatment part 12 and the output port 22a of the first heat treatment furnace 10a. The input side atmosphere replacement structure 40 and the output side atmosphere replacement structure 42 are used to maintain the atmosphere of the internal space of the heat treatment part 12.

[0048] As described above, in the heat treatment system 1 of the present embodiment, the sagger 2 used for heat treatment in one of the two heat treatment furnaces 10a and 10b is kept at a high temperature and transported to the other heat treatment furnace 10b and 10a. Therefore, at the input ports 20a and 20b of the heat treatment furnaces 10a and 10b, it is necessary to have a structure capable of inputting the sagger 2 in a high temperature state, and at the output ports 22a and 22b of the heat treatment furnaces 10a and 10b, it is necessary to have a structure capable of outputting the sagger 2 in a high temperature state. Therefore, the input side atmosphere replacement structure 40 has a structure capable of inputting the sagger 2 in a high temperature state to the heat treatment section 12, and the output side atmosphere replacement structure 42 has a structure capable of outputting the sagger 2 in a high temperature state from the heat treatment section 12. The input side atmosphere replacement structure 40 and the output side atmosphere replacement structure 42 have substantially the same structure. Therefore, the output side atmosphere replacement structure 42 provided on the output port 22a side of the first heat treatment furnace 10a is described in detail below.

[0049] like Figure 5 As shown, the output side atmosphere replacement structure 42 includes a replacement chamber 44 , a heat treatment part side sealing structure 46 , and an external side sealing structure 47 .

[0050] The replacement chamber 44 is arranged adjacent to the heat treatment section 12 on the downstream side of the heat treatment section 12. A door 48a is provided between the replacement chamber 44 and the heat treatment section 12, and a door 48b is provided between the replacement chamber 44 and the output port 22a. The doors 48a and 48b can be opened and closed, and are configured to seal the replacement chamber 44 and the heat treatment section 12 and the output port 22a in a closed state. It should be noted that, hereinafter, the configuration in which the doors 48a and 48b seal the replacement chamber 44 and the heat treatment section 12 and the output port 22a is described. A conveying roller 24 is provided in the replacement chamber 44. The sagger 2 is transported from the heat treatment section 12 to the replacement chamber 44 by the conveying roller 24. An air supply port is provided in the replacement chamber 44, and the same gas as the atmosphere gas supplied to the heat treatment section 12 is supplied from the air supply port. The atmosphere is replaced between the interior of the heat treatment section 12 and the exterior of the first heat treatment furnace 10a in the replacement chamber 44. By configuring the replacement chamber 44, it is possible to suppress the air outside the first heat treatment furnace 10a from invading the heat treatment section 12, and it is possible to suppress the atmosphere gas in the heat treatment section 12 from flowing out to the exterior of the first heat treatment furnace 10a.

[0051] Here, the conveying of the sagger 2 in the replacement chamber 44 is described. The conveying roller 24 disposed near the replacement chamber 44 of the heat treatment section 12 is driven by a roller driving device 26 (hereinafter referred to as a roller driving device 26b) different from the roller driving device 26 (hereinafter referred to as a roller driving device 26a) that drives other conveying rollers 24 in the heat treatment section 12. In addition, the conveying roller 24 disposed in the replacement chamber 44 is driven by a roller driving device 26 (hereinafter referred to as a roller driving device 26c) different from the roller driving devices 26a and 26b that drive the conveying rollers 24 in the heat treatment section 12. In addition, the conveying roller 24 is also disposed outside the replacement chamber 44 (that is, outside the first heat treatment furnace 10a), and the conveying roller 24 disposed outside the replacement chamber 44 is driven by a roller driving device 26 (hereinafter referred to as a roller driving device 26d) different from the roller driving devices 26a, 26b, and 26c. The roller driving devices 26a and 26d drive the conveying rollers 24 so that the conveying rollers 24 rotate at substantially the same speed. The roller driving devices 26b and 26c are configured to change the rotation speed of the conveying rollers 24 by adjusting the output.

[0052] A mechanism for aligning a plurality of saggers 2 arranged side by side in the Y direction is provided near the displacement chamber 44 of the heat treatment section 12. Specifically, a stopper not shown is provided near the boundary with the displacement chamber 44 of the heat treatment section 12. The stopper is configured to be movable in the up-down direction. When the stopper is located at the top, it protrudes upward from the conveying roller 24 and abuts against the side surface of the conveying direction side of the plurality of saggers 2. When the stopper retreats downward, it is stored under the conveying roller 24. By locating the stopper at the top, a plurality of saggers 2 arranged side by side in the Y direction are aligned.

[0053] The sagger 2 is transported in the heat treatment unit 12 by the conveying roller 24 connected to the roller driving device 26a, and is transported by the conveying roller 24 connected to the roller driving device 26b near the displacement chamber 44. At this time, the stopper is located above the conveying roller 24, the door 48a becomes closed, and the door 48b also becomes closed. When the sagger 2 is transported to the vicinity of the boundary with the displacement chamber 44, the multiple saggers 2 arranged side by side in the Y direction are aligned by the stopper. A sensor is provided near the stopper, and when all the saggers 2 arranged side by side in the Y direction are detected by the sensor, the door 48a opens. Then, when the door 48a opens, the output of the roller driving devices 26b and 26c becomes larger, and the stopper moves to the bottom. At this time, the roller driving devices 26b and 26c drive the conveying rollers 24 respectively so that the conveying rollers 24 rotate at approximately the same speed. The output of the roller driving devices 26b and 26c becomes larger, so that the roller driving devices 26b and 26c rotate at a high speed. Then, the sagger 2 is input into the replacement chamber 44 at high speed through the conveying roller 24 connected to the roller driving device 26b, and in the replacement chamber 44, it is conveyed at high speed through the conveying roller 24 connected to the roller driving device 26c. When the sagger 2 is conveyed to the specified position in the replacement chamber 44, the roller driving devices 26b and 26c stop the rotation of the conveying roller 24. Thus, the sagger 2 stops at the specified position in the replacement chamber 44. After that, the door 48a is closed. Thus, the sagger 2 is stored in the replacement chamber 44, and the two doors 48a and 48b become closed. After that, after the set specified time, the door 48b is opened, and the conveying roller 24 in the replacement chamber 44 is rotated by the roller driving device 26c. At this time, the roller driving devices 26c and 26d drive the conveying roller 24 respectively so that the conveying roller 24 rotates at approximately the same speed. Then, the sagger 2 is carried out to the outside of the replacement chamber 44 (ie, outside the first heat treatment furnace 10a) by the conveying rollers 24 in the replacement chamber 44, and is further completely conveyed to the outside of the replacement chamber 44 by the conveying rollers 24 connected to the roller driving device 26d.

[0054] Next, the heat treatment part side sealing structure 46 and the external side sealing structure 47 are described. The heat treatment part side sealing structure 46 is arranged between the replacement chamber 44 and the heat treatment part 12, and has a structure for sealing the replacement chamber 44 and the heat treatment part 12. The external side sealing structure 47 is arranged between the replacement chamber 44 and the outside of the first heat treatment furnace 10a, and has a structure for sealing the replacement chamber 44 and the outside of the first heat treatment furnace 10a. The heat treatment part side sealing structure 46 and the external side sealing structure 47 have the same structure. Therefore, the heat treatment part side sealing structure 46 is described in detail below.

[0055] like Figures 5 to 9As shown, the heat treatment section side sealing structure 46 includes a door 48 a (hereinafter referred to as “door 48 ”), a door pressing device 56 , a chain 70 , a shaft 72 , and a door lifting device 74 .

[0056] The door 48 is disposed between the replacement chamber 44 and the heat treatment unit 12. Figure 6 As shown, the door 48 is a substantially rectangular plate and is larger than the inner surface of the heat treatment section 12 when the heat treatment section 12 is cut in a direction perpendicular to the conveying direction (see Figure 5 ). A chain hanging portion 50 (described in detail below) is connected to the upper portion of the door 48. A chain 70 (described in detail below) is connected to the chain hanging portion 50. The door 48 is connected to the chain 70 by means of the chain hanging portion 50. The door 48 is configured to be movable in the up and down directions using the chain 70. When the door 48 is located at the top, the door 48 is arranged between the heat treatment section 12 and the displacement chamber 44, and blocks the heat treatment section 12 and the displacement chamber 44. That is, when the door 48 is located at the top, the door 48 is in a closed state. On the other hand, when the door 48 moves to the bottom, the door 48 is located at a position lower than the conveying roller 24, and the heat treatment section 12 is connected to the displacement chamber 44. That is, when the door 48 is located at the bottom, the door 48 is in an open state.

[0057] The door 48 is formed by a plate-shaped heat insulating material of a cement system or a calcium silicate system. As described above, the first heat treatment furnace 10a outputs the sagger 2 in a high temperature state. Therefore, near the boundary between the heat treatment unit 12 and the displacement chamber 44, the atmosphere temperature also rises. The door 48 is exposed to the space of the heat treatment unit 12 when closed. By forming the door 48 by a plate-shaped heat insulating material of a cement system or a calcium silicate system, the heat resistance of the door 48 can be ensured, and the thermal deformation of the door 48 can be suppressed.

[0058] like Figure 6 and Figure 7 As shown, a sealing structure 52 is provided on the door 48. The sealing structure 52 is arranged on the surface of the door 48 on the side of the heat treatment unit 12, and is arranged so that when the door 48 is arranged between the heat treatment unit 12 and the displacement chamber 44 (when the door 48 is closed), it is consistent with the end surface of the heat treatment unit 12 on the side of the displacement chamber 44. That is, the sealing structure 52 is arranged in the circumferential direction along the end surface on the output side of the heat treatment unit 12. A frame (not shown) arranged in the circumferential direction along the end surface is provided on the end surface on the output side of the heat treatment unit 12, and the sealing structure 52 is arranged to abut against the frame. That is, the surface of the sealing structure 52 on the side of the heat treatment unit 12 has an abutting surface abutting against the frame.

[0059] The sealing structure 52 includes a sealing portion 53 and a retaining member 54. The sealing portion 53 is formed by one part that is continuous in the circumferential direction. The sealing portion 53 is arranged on the entire circumference of the sealing structure 52. In addition, the sealing portion 53 is formed by a fiber-based sealing member. The retaining member 54 is fixed to the door 48 and is arranged along the sealing portion 53. Specifically, the retaining member 54 is configured to clamp the sealing portion 53 on the surface of the heat treatment portion 12 side of the door 48. The retaining member 54 retains the sealing portion 53. In the present embodiment, the retaining member 54 is formed by a plurality of parts that are divided in the circumferential direction. It should be noted that the retaining member 54 may also be formed by one part that is continuous in the circumferential direction. By using the sealing portion 53, it is possible to seal between the heat treatment portion 12 and the door 48 when the door 48 is closed. In addition, by forming the sealing portion 53 by a fiber-based sealing material, the heat resistance of the sealing portion 53 can be ensured. In addition, in this embodiment, a space is provided inside a frame (not shown) provided at the end surface of the heat treatment unit 12, and a cooling medium is accommodated in the space. By accommodating the cooling medium (such as air, water, etc.) in the frame, the frame can be cooled, and thus the door 48 can be cooled. It should be noted that in this embodiment, the sealing structure 52 is provided on the door 48, but the sealing structure may also be provided on the surface of the frame provided at the end surface of the heat treatment unit 12 that is opposite to the door 48.

[0060] The door pressing device 56 is disposed above the replacement chamber 44, and presses the door 48 toward the heat treatment unit 12 when the door 48 is closed. Figure 5 As shown, the door pressing device 56 is provided at two locations near the upper end and the lower end of the door 48, and presses the upper end and the lower end of the door 48. Figure 8 As shown in (a) and (b) of FIG. 8 , the door pressing device 56 includes a pressing portion 58 , a cylinder 60 , and a connecting structure 62 connecting the pressing portion 58 and the cylinder 60 .

[0061] The pressing portion 58 is cylindrical and is arranged so that the axis is consistent with the conveying direction. The pressing portion 58 is arranged near the door 48. The pressing portion 58 is formed of a ceramic material. The cylinder 60 is connected to the pressing portion 58 by means of a connecting structure 62. The cylinder 60 is arranged on the same straight line as the axis of the pressing portion 58 and is arranged at a position farther from the door 48 than the pressing portion 58 (in the +X direction). The cylinder 60 presses the pressing portion 58 toward the door 48 by means of the connecting structure 62. Figure 8As shown in (a), when the door 48 is in the closed position, if the pressing portion 58 is pressed by the cylinder 60, the pressing portion 58 abuts against the surface of the door 48 on the side opposite to the heat treatment portion 12 side (the surface on the side of the replacement chamber 44 in the heat treatment portion side sealing structure 46). By pressing the door 48 toward the heat treatment portion 12 side by the pressing portion 58, the sealing performance of the sealing portion 53 can be improved. In addition, the pressing portion 58 abuts against the door 48. As described above, the door 48 is at a high temperature in the closed state. By forming the pressing portion 58 from a ceramic material, the heat resistance of the pressing portion 58 can be ensured. It should be noted that in the present embodiment, the pressing portion 58 is formed of a ceramic material as a whole, but is not limited to this structure. The pressing portion 58, especially the front end portion 58a, only needs to have high heat resistance, and only the front end portion 58a can be formed of a ceramic material.

[0062] The connection structure 62 includes: a sleeve 64, a joint 66, and a sealing portion 68. The sleeve 64 is mounted on the wall surface of the displacement chamber 44, and the end of the pressing portion 58 on the cylinder 60 side is inserted therein in a slidable manner. The sleeve 64 is formed of a heat-resistant material. The joint 66 is arranged between the pressing portion 58 and the cylinder 60. In this embodiment, the joint 66 is a floating joint. The gap between the sleeve 64 and the pressing portion 58 is sealed by the sealing portion 68. The sealing portion 68 is formed of a fiber-based sealing material. In the connection structure 62, the sleeve 64 and the sealing portion 68 are arranged at a position close to the pressing portion 58, that is, a position relatively close to the door 48. Therefore, the sleeve 64 and the sealing portion 68 are prone to high temperature. By forming the sleeve 64 and the sealing portion 68 from a heat-resistant material, the heat resistance of the sleeve 64 and the sealing portion 68 can be ensured. On the other hand, since the cylinder 60 is connected to the pressing portion 58 via the connecting structure 62, it is arranged at the pressing portion 58, that is, at a position relatively far from the door 48. By arranging the cylinder 60 via the connecting structure 62, thermal influence on the cylinder 60 can be suppressed.

[0063] The chain 70 is used to open and close the door 48. Fig. 9As shown, the chain 70 is arranged in the chain hanging part 50. The chain hanging part 50 is provided on the upper part of the door 48 and on the top wall of the replacement chamber 44. Specifically, two chain hanging parts 50 are provided on the top wall of the replacement chamber 44. The two chain hanging parts 50 are located on the upper part of the door 48, one is provided near the end of the door 48 in the +Y direction, and the other is provided near the end of the door 48 in the -Y direction. The chain hanging part 50 extends upward from the top wall of the replacement chamber 44. The chain hanging part 50 is provided with a hole 50a extending in the up-down direction and a through hole 50b extending parallel to the upper surface of the door 48 (i.e., in the Y direction). The lower end of the hole 50a is open inside the replacement chamber 44, and the upper end of the hole 50a is connected to the through hole 50b. The chain 70 is arranged in the hole 50a. The through hole 50b is provided near the upper end of the chain hanging part 50. The shaft 72 passes through the through hole 50b. The through hole 50b is provided with a seal 76, which seals the gap between the shaft 72 and the chain hanging part 50. This prevents the inside of the replacement chamber 44 from communicating with the outside of the replacement chamber 44 via the hole 50a and the through hole 50b.

[0064] The chain 70 is configured such that the lower end is connected to the door 48, and the upper end is connected to the shaft 72. Specifically, a sprocket is provided at the connection portion between the shaft 72 and the chain 70, and the chain 70 is connected to the sprocket. The shaft 72 is configured such that the two ends respectively penetrate the through holes 50b of the two chain hanging parts 50, and the central part is arranged above the door 48. The shaft 72 is arranged above the door 48 along the upper surface of the door 48. The shaft 72 is supported so as to be rotatable around its axis, and is rotated by the driving force of the door lifting device 74 being transmitted. The door lifting device 74 is a driving device (such as a motor) that drives the shaft 72. The door lifting device 74 is connected to the shaft 72 by means of a power transmission mechanism. When the driving force of the door lifting device 74 is transmitted to the shaft 72 via the power transmission mechanism (such as a mechanism based on sprockets and chains), the shaft 72 rotates. The door lifting device 74 can rotate the shaft 72 in two directions (forward and reverse) by adjusting the output. Hereinafter, one of the rotation directions of the shaft 72 is referred to as a “first direction”, and the rotation direction opposite to the first direction is referred to as a “second direction”.

[0065] When the shaft 72 is rotated in the first direction, the chain 70 connected to the shaft 72 is wound around the sprocket teeth of the shaft 72. That is, when the shaft 72 is rotated in the first direction, the shaft 72 winds up the chain 70. The lower end of the chain 70 is connected to the door 48. Therefore, when the shaft 72 winds up the chain 70, the door 48 moves upward. On the other hand, when the shaft 72 is rotated in the second direction, the chain 70 wound around the sprocket teeth of the shaft 72 moves downward. That is, when the shaft 72 is rotated in the second direction, the shaft 72 unwinds the chain 70. When the shaft 72 unwinds the chain 70, the door 48 moves downward.

[0066] As described above, the door 48 moves in the up and down directions by the chain 70. That is, the door 48 is held in a freely suspended state by the chain 70. In addition, as described above, the joint 66 of the door pressing device 56 is a floating joint. The door 48 is formed of a ceramic material, and therefore, heat resistance can be ensured, but it is possible that it is slightly thermally deformed due to exposure to high temperatures. For example, when the door 48 slides and opens and closes, when the door 48 is deformed by thermal deformation, sometimes a part of the sealing portion 53 provided in the sealing structure 52 does not contact the end of the heat treatment portion 12, and the sealing performance of the sealing portion 53 is reduced. In this embodiment, the door 48 is suspended by the chain 70, and the door pressing device 56 uses a floating joint, whereby, even when the door 48 is thermally deformed, the sealing portion 53 can be made to contact the end of the heat treatment portion 12 as a whole by pressing with the door pressing device 56. Therefore, the sealing performance of the sealing portion 53 (i.e., the door 48) can be ensured.

[0067] In addition, by rolling up or releasing the chain 70 using the shaft 72, the through hole 50b provided in the chain hanging portion 50 and through which the shaft 72 passes can be made smaller. Therefore, the area in which the sealing portion 76 is arranged can be made smaller. For example, when a cylinder or the like is used to move the chain in the up-down direction, a guide portion in the up-down direction is provided in the chain hanging portion, and the guide portion needs to be sealed. In this case, the guide portion needs to have a length corresponding to the dimension of the door 48 in the up-down direction, so that a larger range in the up-down direction needs to be sealed. In this embodiment, by rolling up or releasing the chain 70 using the shaft 72, the range to be sealed can be made smaller.

[0068] The precautions related to the heat treatment system 1 described in the embodiment are described. The replacement chamber 44 of the embodiment is an example of a "replacement unit", the door pressing device 56 is an example of a "pressing device", the connecting structure 62 is an example of a "connecting unit", and the door lifting device 74 is an example of a "driving device".

[0069] The specific examples of the technology disclosed in this specification are described in detail above, however, these specific examples are only examples and do not limit the claims. The technology described in the claims includes examples obtained by various deformations and changes of the specific examples illustrated above. In addition, the technical elements described in this specification or the drawings exert technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of application. In addition, the technology illustrated in this specification or the drawings achieves multiple purposes at the same time, and the solution to achieve one of the purposes itself has technical usefulness.

Claims

1. A heat treatment system comprising: a first supply device, a first heat treatment furnace, a first recovery device, a second supply device, a second heat treatment furnace, and a second recovery device, The heat treatment system is characterized in that The first supply device is arranged near the second recovery device, and supplies the processed object to the sagger conveyed from the second recovery device. The first heat treatment furnace comprises: an input port, the input port being arranged near the first supply device and being used for inputting the sagger supplied with the processed object by the first supply device; An output port, through which the sagger inputted is outputted; a heat treatment section disposed between an input port and an output port of the first heat treatment furnace, and heat-treating the object to be treated supplied to the sagger while the sagger is being transported from the input port to the output port of the first heat treatment furnace; as well as a first conveying device for conveying the sagger in a first direction from an input port toward an output port of the first heat treatment furnace, The first recovery device is disposed near the output port of the first heat treatment furnace, and recovers the processed object heat-treated in the first heat treatment furnace from the sagger. The second supply device is arranged near the first recovery device, and supplies new processed objects to the sagger from which the processed objects have been recovered by the first recovery device. The second heat treatment furnace comprises: an input port, the input port being arranged near the second supply device and being used for inputting the sagger supplied with the processed object by the second supply device; An output port, through which the sagger inputted is outputted; a heat treatment section disposed between an input port and an output port of the second heat treatment furnace, and heat-treating the object to be treated supplied to the sagger while the sagger is being transported from the input port to the output port of the second heat treatment furnace; as well as a second conveying device, the second conveying device conveying the sagger from an input port to an output port of the second heat treatment furnace in a second direction opposite to the first direction; The second recovery device is disposed near the output port of the second heat treatment furnace, and recovers the processed object heat-treated in the second heat treatment furnace from the sagger. The first heat treatment furnace and the second heat treatment furnace each further include a replacement portion, which is disposed between the heat treatment portion of the heat treatment furnace and an output port of the heat treatment furnace to isolate the heat treatment portion of the heat treatment furnace from the outside of the output port of the heat treatment furnace. The replacement section includes openable and closable doors formed of a heat insulating material between the replacement section and the heat treatment section of the heat treatment furnace and between the replacement section and the outlet of the heat treatment furnace.

2. The heat treatment system according to claim 1, characterized in that: The first heat treatment furnace and the second heat treatment furnace each further include: an abutment surface, the abutment surface being arranged between at least one of the doors arranged in the replacement portion and the heat treatment portion, and abutting against the entire outer periphery of the door when the door is closed; as well as A pressing device is arranged outside the replacement portion and presses the door toward the abutment surface when the door is closed.

3. The heat treatment system according to claim 2, characterized in that: The abutting surface includes a sealing portion that seals between the door and the abutting surface. The sealing portion is formed of a fiber-based sealing material.

4. The heat treatment system according to claim 2, characterized in that: The pressing device comprises: A pressing portion, the pressing portion being capable of abutting against the door; a cylinder disposed closer to the output port than the pressing portion and pressing the pressing portion; and a connecting portion connecting the pressing portion and the cylinder, The pressing portion and the connecting portion are formed of a heat-resistant material.

5. The heat treatment system according to claim 4, characterized in that: The pressing portion is formed of a ceramic material.

6. The heat treatment system according to claim 4 or 5, characterized in that: The first heat treatment furnace and the second heat treatment furnace each further include a chain connected to an upper end of at least one of the doors disposed in the replacement portion to support the door.

7. The heat treatment system according to claim 6, characterized in that: The first heat treatment furnace and the second heat treatment furnace each further include: a shaft, the chain is wound up by rotating the shaft in a first direction, and the chain is unwound by rotating the shaft in a second direction opposite to the first direction; as well as a drive device that causes the shaft to rotate, The shaft is arranged above the chain with its axis horizontal and perpendicular to the conveying direction. The door moves upward by winding up the chain using the shaft, and moves downward by unwinding the chain using the shaft.

8. The heat treatment system according to claim 7, characterized in that: The door is configured to be in an open state by being moved downward.

9. The heat treatment system according to claim 1, characterized in that: The first heat treatment furnace and the second heat treatment furnace each further include an input side replacement portion, which is arranged between the heat treatment portion of the heat treatment furnace and the input port of the heat treatment furnace to isolate the heat treatment portion of the heat treatment furnace from the outside of the input port of the heat treatment furnace. The input-side replacement section includes openable and closable doors formed of a heat insulating material between the input-side replacement section and the heat treatment section of the heat treatment furnace and between the input-side replacement section and the heat treatment furnace.

10. An atmosphere replacement structure for maintaining the atmosphere of an inner space of a heat treatment portion in a heat treatment furnace, The heat treatment furnace has: An input port, at which a sagger supplied with processed objects is input into the furnace; a heat treatment section that performs heat treatment on the workpiece supplied into the sagger input from the input port; an output port at which the sagger supplied with the object to be processed which has been heat-treated in the heat treatment section is output to the outside of the furnace; and a first conveying device, which conveys the sagger from the input port to the output port, The atmosphere replacement structure is characterized by comprising: a displacement chamber disposed between the heat treatment portion and the output port; a first door disposed between the replacement chamber and the heat treatment part; and a second door, the second door being disposed between the displacement chamber and the output port, The first door and the second door are respectively formed of a heat insulating material.

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