Heat treatment system

Abstract

To appropriately confirm a state of a sagger used when performing heat treatment of treatment targets.SOLUTION: A heat treatment system includes: a heat treatment furnace performing heat treatment of treatment targets housed in a sagger while the sagger is conveyed from a carry-in port to a carry-out port; a conveying device which conveys the sagger conveyed from the carry-out port of the heat treatment furnace to the carry-in port of the heat treatment furnace; a recovery device which is provided on a carrying route of the conveying device and recovers from the sagger the treatment targets on which heat treatment is performed by the heat treatment furnace; a supply device which is on the carrying route of the conveying device, is provided between the recovery device and the carry-in port, and supplies a sagger that does not house a treatment target with a treatment target before heat treatment; and a hood covering the carrying route. The carrying route is provided with: a first carrying route provided in at least a part of an area between the recovery device and the supply device; and a second carrying route provided for an area other than the area where the first carrying route is provided in the carrying routes. The hood is provided in the second carrying route but not in the first carrying route.SELECTED DRAWING: Figure 5

Description

[Technical field]

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

[0002] A heat treatment furnace (e.g., a roller hearth kiln, a pusher kiln, etc.) may be used to heat treat an object to be treated. For example, when a powder or other object to be treated is heat treated in a heat treatment furnace, the object is heat treated while being accommodated in a sagger. The sagger is reused and used repeatedly. For example, Patent Document 1 discloses a heat treatment system including a heat treatment furnace and a conveying device that conveys the sagger from the discharge port to the entrance port of the heat treatment furnace. In the heat treatment system, a recovery device that recovers the object to be treated from inside the sagger and a supply device that supplies the object to be treated to the sagger are installed on the conveying path of the conveying device. Patent Document 1 also discloses a hood that covers the conveying path of the conveying device. This prevents foreign matter from being mixed into the sagger while the sagger is conveyed along the conveying path by the conveying device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7041300 Summary of the Invention [Problem to be solved by the invention]

[0004] In the heat treatment system of Patent Document 1, the saggers used for the heat treatment of the objects to be treated are reused. When the saggers are used repeatedly, they may break. In addition, the saggers are reused after the objects to be treated are collected by the collection device, but the objects to be treated after the heat treatment may remain in the saggers. In such a case, it is necessary to perform a process of removing the broken saggers or a process of removing the objects to be treated from the saggers in which the objects to be treated remain before the supply device supplies the objects to the saggers before the heat treatment. For this reason, it is required to check the state of the saggers after the objects to be treated are collected by the collection device. For example, if the saggers after the objects to be treated are collected by the collection device are checked using a laser or the like, it is possible to automatically check the state of the saggers, but in order to check the state of the saggers more accurately, it is necessary to visually check the saggers. However, in the heat treatment system of Patent Document 1, there is a problem that the state of the saggers cannot be visually checked because the conveying path is covered by a hood.

[0005] This specification discloses a technique for appropriately checking the condition of a sagger used when heat treating a workpiece. [Means for solving the problem]

[0006] In a first aspect of the technology disclosed in the present specification, the heat treatment system includes a heat treatment furnace, a transport device, a recovery device, a supply device, and a hood. The heat treatment furnace includes an entrance and an exit, and heat-treats the workpiece contained in the sagger while transporting the sagger from the entrance to the exit. The transport device transports the sagger discharged from the exit of the heat treatment furnace to the entrance of the heat treatment furnace. The recovery device is provided on the transport path of the transport device, and recovers the workpiece heat-treated in the heat treatment furnace from the sagger. The supply device is provided on the transport path of the transport device between the recovery device and the entrance, and supplies the workpiece before heat treatment to the sagger not containing the workpiece. The hood covers the transport path. The transport path includes a first transport path provided in at least a part of the area between the recovery device and the supply device, and a second transport path provided in the transport path other than the area where the first transport path is provided. The hood is provided on the second transport path and is not provided on the first transport path.

[0007] In the above heat treatment system, the first transport path provided in a part of the area between the recovery device and the supply device is not covered with a hood, so that an area where the state of the saggers can be visually observed can be provided between the recovery device and the supply device. This makes it easier to check the state of the saggers after the objects to be treated are recovered by the recovery device, and makes it possible to more accurately check whether the saggers are in a reusable state. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of a heat treatment system according to a first embodiment. [Diagram 2] FIG. 2 is a block diagram showing a control system of the heat treatment system according to the first embodiment. [Diagram 3] FIG. 2 is a diagram showing a schematic configuration of a heat treatment furnace, and is a vertical cross-sectional view of the heat treatment furnace taken along a plane parallel to the conveying direction of the saggers. [Figure 4] 4 is a cross-sectional view taken along line IV-IV in FIG. 3 . [Diagram 5] FIG. 4 is a top view showing a first transport path and a second transport path. [Figure 6] FIG. 4 is a side view showing a first transport path and a second transport path.

[0009] The main features of the embodiments described below are listed below. Note that the technical elements described below are independent technical elements that exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing.

[0010] In a second aspect of the technology disclosed in this specification, in the first aspect described above, the hood may include an opening provided between the first transport path and the second transport path, and a blocking portion provided at the opening to block the space inside the hood from the space outside the hood. With this configuration, it is possible to prevent foreign matter from entering the space in the second transport path covered by the hood from the space on the first transport path side that is open without the hood.

[0011] In a third aspect of the technology disclosed in the present specification, in the first or second aspect, the first transport path may have an outer edge parallel to the transport direction of the sagger. The heat treatment system may further include a sensor that detects whether an object is located on the outer edge. With this configuration, it is possible to detect that a worker has entered the first transport path without a hood.

[0012] In a fourth aspect of the technology disclosed in this specification, in the third aspect, the conveying device may stop conveying the sagger when the sensor detects an object, and may convey the sagger when the sensor does not detect an object. With this configuration, when a worker enters the first conveying path, the conveying device can automatically stop conveying the sagger.

[0013] In a fifth aspect of the technique disclosed in the present specification, in any one of the first to fourth aspects, the first transport path may have an outer edge parallel to the transport direction of the sagger. The sagger may have a first side located on the outer edge side and a second side located opposite to the first side. The heat treatment system may further include a reflector disposed on the second side of the sagger transported along the first transport path, and reflecting the second side when the sagger is viewed from the first side. According to this configuration, by providing the reflector, the first side can be directly viewed from the first side of the sagger, and the second side of the sagger reflected by the reflector can also be viewed. This allows the second side, which is a blind spot from the first side, to be viewed.

[0014] In a sixth aspect of the technique disclosed in the present specification, in any one of the first to fifth aspects described above, the heat treatment system may further include an imaging device provided in the first transport path, which images the saggers transported along the first transport path. With this configuration, the state of the saggers can be confirmed by imaging with the imaging device. Also, since there is no hood in the first transport area, there are fewer limitations on imaging conditions such as lighting, unlike the second transport area covered by a hood. Therefore, the saggers can be appropriately imaged.

[0015] In a seventh aspect of the technique disclosed in the present specification, in the sixth aspect, a plurality of imaging devices may be disposed on the first conveying path. With such a configuration, the sagger can be imaged by the plurality of imaging devices, and the state of the sagger can be checked more accurately.

[0016] In an eighth aspect of the technique disclosed in the present specification, in any one of the first to seventh aspects, the heat treatment system may further include a cleaning device provided in the first transport path and configured to clean the saggers transported through the first transport area. With this configuration, when the saggers are attached with objects to be treated or foreign matter, the saggers can be cleaned. This allows the objects to be treated or foreign matter adhering to the saggers to be removed through the first transport path, and the saggers from which the objects to be treated or foreign matter have been removed can be transported to the supply device without removing the saggers from the transport path.

[0017] As a ninth aspect of the technique disclosed in the present specification, in the sixth aspect described above, the cleaning device may be a suction nozzle that sucks up the deposits adhering to the sagger. EXAMPLES

[0018] A heat treatment system 1 according to the present embodiment will be described with reference to the drawings. As shown in Fig. 1 and Fig. 2, the heat treatment system 1 includes a heat treatment furnace 10, a circulating transport device 30, a supply device 40, a recovery device 42, a cleaning device 44, a crack detection device 46, and a management device 48.

[0019] The heat treatment system 1 heat-treats the object to be treated housed in the sagger 2 (see FIG. 3). In this embodiment, the object to be treated housed in the sagger 2 is a powder of a positive electrode material for a lithium ion battery. In the heat treatment system 1 of this embodiment, the sagger 2 is configured to circulate between the supply device 40, the heat treatment furnace 10, the recovery device 42, the cleaning device 44, and the crack detection device 46. The object to be treated is heat-treated while the sagger 2 is transported in the heat treatment furnace 10. As shown in FIG. 2, the management device 48 is connected to the heat treatment furnace 10, the circulation transport device 30, the supply device 40, the recovery device 42, the cleaning device 44, and the crack detection device 46. The management device 48 controls the operation of the heat treatment furnace 10, the circulation transport device 30, the supply device 40, the recovery device 42, the cleaning device 44, and the crack detection device 46.

[0020] The heat treatment furnace 10 heat-treats the object to be treated in the sagger 2. As shown in Figures 3 and 4, the heat treatment furnace 10 includes a furnace body 12 and a transport device (24, 26). The heat treatment furnace 10 heat-treats the object to be treated housed in the sagger 2 while the sagger 2 is transported within the furnace body 12 by the transport device (24, 26).

[0021] The furnace body 12 has an outer shape of a substantially rectangular parallelepiped, and the heat treatment space therein is surrounded by a ceiling wall 14a, a bottom wall 14b, a furnace inlet wall 14c, a furnace outlet wall 14d, and side walls 14e and 14f. As shown in FIG. 3, the ceiling wall 14a is arranged parallel to the bottom wall 14b (i.e., parallel to the XY plane). The furnace inlet wall 14c is arranged at the inlet end of the transport path and is arranged perpendicular to the transport direction (i.e., parallel to the YZ plane). The furnace outlet wall 14d is arranged at the outlet end of the transport path and is arranged parallel to the furnace inlet wall 14c (i.e., parallel to the YZ plane). As shown in FIG. 4, the side walls 14e and 14f are arranged parallel to the transport direction and perpendicular to the ceiling wall 14a and the bottom wall 14b (i.e., parallel to the XZ plane). In the heat treatment space in the furnace body 12, a plurality of heaters 16a, 16b and a plurality of conveying rollers 24 are arranged. The heaters 16a are arranged above the conveying rollers 24 at a predetermined interval in the conveying direction, and the heaters 16b are arranged below the conveying rollers 24 at a predetermined interval in the conveying direction. When the heaters 16a, 16b generate heat, the space 18 in the furnace body 12 is heated and the object to be treated housed in the sagger 2 is heated. As shown in FIG. 3, an opening 15a is formed in the furnace inlet wall 14c, and an opening 15b is formed in the furnace outlet wall 14d. The sagger 2 is conveyed into the heat treatment furnace 10 from the opening 15a by the conveying device (24, 26) and conveyed out of the heat treatment furnace 10 from the opening 15b. That is, the opening 15a is used as an inlet, and the opening 15b is used as an outlet.

[0022] The conveying device (24, 26) includes a plurality of conveying rollers 24 and a driving device 26. The conveying rollers 24 convey the sagger 2. The conveying device (24, 26) conveys the sagger 2 into the heat treatment furnace 10 through the opening 15a, and conveys the sagger 2 out of the heat treatment furnace 10 through the opening 15b. The conveying roller 24 is cylindrical, and its axis extends in a direction perpendicular to the conveying direction (i.e., in the Y direction). All of the conveying rollers 24 have the same diameter, and are disposed at equal intervals with a constant pitch in the conveying direction. The conveying rollers 24 are supported rotatably around their axes, and rotate when a driving force of the driving device 26 is transmitted to them. The driving device 26 is a driving device (e.g., a motor) that drives the conveying rollers 24. The driving device 26 is connected to the conveying rollers 24 via a power transmission mechanism. When the driving force of the drive unit 26 is transmitted to the transport rollers 24 via a power transmission mechanism (e.g., a mechanism using a sprocket and a chain), the transport rollers 24 rotate. The drive unit 26 drives each of the transport rollers 24 so that the transport rollers 24 rotate at approximately the same speed. The drive unit 26 is controlled by a control unit 28. In this embodiment, the multiple transport rollers 24 all have the same diameter, but this is not limited to the configuration. Transport rollers of different diameters may be installed inside the heat treatment furnace 10.

[0023] As shown in FIG. 1, the circulating conveying device 30 conveys the saggers 2 discharged from the discharge outlet (i.e., the opening 15b) of the heat treatment furnace 10 to the discharge inlet (i.e., the opening 15a) of the heat treatment furnace 10. The circulating conveying device 30 includes a plurality of conveying rollers 32 (see FIGS. 5 and 6) and a driving device 34 (see FIG. 2). The conveying rollers 32 are cylindrical, and their axes extend in a direction perpendicular to the conveying direction. All of the conveying rollers 32 have the same diameter and are disposed at equal intervals in the conveying direction at a constant pitch. The conveying rollers 32 are supported so as to be rotatable about their axes, and rotate when a driving force of the driving device 34 is transmitted to the conveying rollers 32. The driving device 34 is a driving device (e.g., a motor) that drives the conveying rollers 32. The driving device 34 is connected to the conveying rollers 24 via a power transmission mechanism. When the driving force of the drive device 34 is transmitted to the transport rollers 32 via a power transmission mechanism (e.g., a mechanism using a sprocket and a chain), the transport rollers 32 rotate. The drive device 34 drives each of the transport rollers 32 so that the transport rollers 32 rotate at approximately the same speed. In this embodiment, all of the multiple transport rollers 32 have the same diameter, but this is not limited to the configuration. Transport rollers of different diameters may be installed on the transport path of the circulating transport device 30.

[0024] As shown in FIG. 5 and FIG. 6, the conveying path of the circulating conveying device 30 has an area covered by the hood 54 and an area not covered by the hood 54. In detail, the conveying path of the circulating conveying device 30 has an area not covered by the hood 54 between the collecting device 42 and the supplying device 40. Hereinafter, the conveying path of the circulating conveying device 30 corresponding to the area not covered by the hood 54 is referred to as the "first conveying path 50", and the conveying path corresponding to the area covered by the hood 54 is referred to as the "second conveying path 52". As shown in FIG. 1, in this embodiment, the first conveying path 50 is provided between the crack detecting device 46 and the supplying device 40. The first conveying path 50 and the second conveying path 52 will be described in detail later.

[0025] As shown in FIG. 1, the supply device 40 is disposed on the transport path of the circulating transport device 30. The supply device 40 is disposed upstream of the entrance of the heat treatment furnace 10, and in this embodiment, it is disposed between the crack detection device 46 and the entrance of the heat treatment furnace 10. In addition, in this embodiment, the supply device 40 is disposed downstream of the first transport path 50 (i.e., the area where the transport path is not covered by the hood 54). The supply device 40 is a device that supplies the object to be treated (i.e., powder) into the sagger 2. The supply device 40 may be configured to supply powder into the sagger 2, and the specific structure is not particularly limited. For example, the supply device 40 includes a supply unit and a leveling unit. The supply unit is configured to supply powder into the sagger 2. Specifically, the supply unit includes a supply port that drops powder from above the sagger 2 into the sagger 2. The supply port is disposed so as to be located above the center of the sagger 2 when the sagger 2 is disposed in the supply unit. The supply unit includes a positioning device, and the positioning device positions the sagger 2 transported to the supply unit so that it is located below the supply port. The supply unit may be provided with a plurality of supply ports. The supply unit supplies powder into the sagger 2 by dropping the powder from above, so that 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 below the supply port. The leveling unit levels 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 contained in the sagger 2 becomes approximately horizontal.

[0026] The recovery device 42 is disposed on the transport path of the circulating transport device 30. The recovery device 42 is disposed downstream of the discharge port of the heat treatment furnace 10, and in this embodiment, it is disposed between the discharge port of the heat treatment furnace 10 and the cleaning device 44. The recovery device 42 is a device that recovers the object to be treated (i.e., powder) that has been heat-treated in the heat treatment furnace 10 from the sagger 2. The recovery device 42 only needs to be configured to recover the powder from the sagger 2, and the specific structure is not particularly limited. For example, the recovery device 42 includes an inversion recovery section that recovers the object to be treated (powder in this embodiment) that has adhered to the surface of the sagger 2 by using air to peel it off and recover it. The inversion recovery section moves the powder in the sagger 2 to a recovery container by inverting the sagger 2 in the vertical direction. As a result, almost all of the powder contained in the sagger 2 moves to the recovery container. After that, the inverting and collecting unit inverts the sack 2 again to return it to its original orientation. The air collecting unit is used after the powder in the sack 2 is collected by the inverting and collecting unit. The air collecting unit sucks the air in the sack 2 while blowing air onto the inner surface of the sack 2. By blowing air onto the inner surface of the sack 2, the powder adhering to the inner surface of the sack 2 is peeled off from the inner surface. When the air in the sack 2 is sucked while blowing air onto the inner surface of the sack 2, the powder peeled off from the inner surface of the sack 2 is sucked together with the air. This allows the powder remaining on the inner surface of the sack 2 to be collected, and the powder collection rate increases. In the above example, the collecting device 42 includes an air collecting unit, but is not limited to such a configuration. For example, the powder remaining on the inner surface of the sack 2 may be configured to be peeled off from the inner surface of the sack 2 by a rotating brush and collected.

[0027] The cleaning device 44 is disposed on the conveying path of the circulating conveying device 30. The cleaning device 44 is disposed between the collecting device 42 and the crack detecting device 46. The cleaning device 44 is a device for cleaning the inner surface of the sagger 2 after the object to be treated (i.e., powder) is collected by the collecting device 42. The cleaning device 44 is not particularly limited in its specific structure as long as it is configured to clean the inner surface of the sagger 2. For example, the cleaning device 44 uses a rotating brush to peel off the material adhering to the inner surface of the sagger 2 while sucking in the air, etc., in the sagger 2. The sucked in air, etc., contains the peeled off material. By cleaning the inner surface of the sagger 2 with the cleaning device 44, the powder, etc. remaining on the inner surface of the sagger 2 can be completely removed.

[0028] The crack detection device 46 is disposed on the conveying path of the circulating conveying device 30. The crack detection device 46 is disposed between the cleaning device 44 and the supply device 40. In this embodiment, the crack detection device 46 is disposed upstream of the first conveying path 50 (i.e., the area where the conveying path is not covered by the hood 54). The crack detection device 46 is a device for inspecting whether the sagger 2 is cracked by detecting a crack in the sagger 2. The sagger 2 is repeatedly used in the heat treatment furnace 10 for the heat treatment of the object to be treated. The crack detection device 46 inspects whether the sagger 2 is cracked before being reused after being used in the heat treatment furnace 10 for the heat treatment of the object to be treated. Note that the crack detection device 46 only needs to be configured to detect a crack in the sagger 2, and the specific configuration is not particularly limited. For example, the crack detection device 46 may detect a crack in the sagger 2 using a laser. The crack detection device 46 may also detect a crack in the sack 2 by sealing a gas in the sack 2 and measuring the pressure inside the sack 2. If a crack in the sack 2 is detected, the sack 2 is removed from the conveying path of the circulating conveying device 30. If a crack in the sack 2 is not detected, the sack 2 is conveyed to the supply device 40 by the circulating conveying device 30.

[0029] Next, the first conveying path 50 and the second conveying path 52 will be described in more detail. As described above, the conveying path of the circulating conveying device 30 includes the first conveying path 50 that is not covered by the hood 54 and the second conveying path 52 that is covered by the hood 54. As shown in FIG. 1, the first conveying path 50 is provided only in a portion between the crack detection device 46 and the supply device 40. In other words, the conveying path of the circulating conveying device 30 is the first conveying path 50 in which only a portion between the crack detection device 46 and the supply device 40 is not covered by the hood 54, and the second conveying path 52 in which most of the conveying path is covered by the hood 54. Since the second conveying path 52 is covered by the hood 54, it is possible to prevent foreign matter from entering the sagger 2 conveyed on the second conveying path 52 from the outside. On the other hand, since the second conveying path 52 is covered by the hood 54, the sagger 2 conveyed on the second conveying path 52 cannot be visually observed.

[0030] The first conveying path 50 is not covered by the hood 54. Therefore, the saggers 2 conveyed on the first conveying path 50 can be visually observed from outside the conveying path of the circulating conveying device 30. After the objects to be treated in the saggers 2 are collected by the collecting device 42, the saggers 2 are conveyed to the first conveying path 50 after passing through the cleaning device 44 and the crack detection device 46. That is, the saggers 2 are cleaned by the cleaning device 44, inspected by the crack detection device 46 for cracks, and then conveyed to the first conveying path 50. Therefore, the first conveying path 50 conveys saggers 2 whose insides are cleaned and that are not cracked. However, even if the saggers 2 are cleaned by the cleaning device 44, objects to be treated may remain in the saggers 2. For example, the corners of the rectangular saggers 2 are more difficult to clean than other parts, and objects to be treated may remain in the corners of the saggers 2. In addition, when the recovery device 42 recovers the objects to be treated in the sack 2, if there are many objects remaining in the sack 2, the cleaning device 44 may not be able to completely remove (e.g., suck) the objects to be treated in the sack 2. In addition, since the recovery device 42 recovers the objects to be treated from the sack 2 by inverting the sack 2, the objects to be treated that are blown up during the inversion may adhere to the outer surface of the sack 2. In such a case, even after the sack 2 is cleaned by the cleaning device 44, the objects to be treated may still adhere to the inside or outer surface of the sack 2. In addition, the crack detection device 46 may not be able to detect the cracks in the sack 2. For example, when the cracks generated in the sack 2 are minute or when the cracks are present at the corners of the sack 2, it is difficult for the crack detection device 46 to detect the cracks in the sack 2. For this reason, in this embodiment, after the sagger 2 has been transported through the cleaning device 44 and the crack detection device 46, the worker visually checks the sagger 2 to see if there are any objects not cleaned by the cleaning device 44 or any cracks not detected by the crack detection device 46. Since the first transport path 50 is not covered by the hood 54, the condition of the sagger 2 can be visually checked while it is being transported along the first transport path 50.

[0031] The hood 54 is provided with an opening 54a between the first conveying path 50 and the second conveying path 52. The opening 54a is provided perpendicular to the conveying direction of the saggers 2. By providing the opening 54a, the saggers 2 can pass between the first conveying path 50 and the second conveying path 52.

[0032] In addition, a door 56 is installed in the opening 54a. The door 56 is a flat plate and has a shape that covers the opening 54a. The door 56 can be moved in the vertical direction by a driving device (not shown). When the door 56 is located at the lower position, it is in a closed state that covers the opening 54a, and when it is located at the upper position, it is in an open state that the opening 54a is open. The door 56 is in an open state when the sack 2 is transported between the first transport path 50 and the second transport path 52, and is in a closed state when the sack 2 is not transported between the first transport path 50 and the second transport path 52. By installing the door 56 in the opening 54a, the sack 2 can be transported through the opening 54a between the first transport path 50 and the second transport path 52, and it is possible to suppress the intrusion of foreign matter and the like into the second transport path 52 from the outside of the hood 54 through the opening 54a.

[0033] In this embodiment, the door 56 is installed at the opening 54a, but the present invention is not limited to such a configuration. Any configuration may be used to prevent foreign objects from entering the second conveying path 52 from the outside of the hood 54. For example, an air curtain may be installed at the opening 54a. The air curtain has an air outlet. The air outlet is configured to blow air from the air outlet in a direction perpendicular to the conveying direction of the sagger 2 along the opening 54a. Air is constantly blown out from the air outlet while the sagger 2 is being conveyed between the first conveying path 50 and the second conveying path 52. Even when the air curtain is installed at the opening 54a, the sagger 2 can be conveyed between the first conveying path 50 and the second conveying path 52, and the intrusion of foreign objects from the outside of the hood 54 into the second conveying path 52 through the opening 54a can be prevented.

[0034] Sensors (58a, 58b) are installed on the first transport path 50. The sensors (58a, 58b) are optical sensors equipped with a light-emitting unit 58a and a light-receiving unit 58b. The first transport path 50 has two outer edges 50a, 50b parallel to the transport direction of the sagger 2. The sensors (58a, 58b) are arranged to detect objects located on the outer edges 50a, 50b of the first transport path 50. That is, the light-emitting unit 58a and the light-receiving unit 58b are installed on the outer edge 50a side and the outer edge 50b side, respectively. In addition, the light-emitting unit 58a is arranged downstream of the outer edges 50a, 50b, and the light-receiving unit 58b is arranged upstream of the outer edges 50a, 50b. The light-emitting unit 58a is arranged to irradiate light along the outer edges 50a, 50b, and the light-receiving unit 58b is arranged to receive the light irradiated from the light-emitting unit 58a. The light emitting unit 58a may be disposed upstream of the outer edges 50a and 50b, and the light receiving unit 58b may be disposed downstream of the outer edges 50a and 50b. Since the first conveying path 50 is not covered by the hood 54, there is a risk that a worker may enter the first conveying path 50. When a worker enters the first conveying path 50 from outside the first conveying path 50 beyond the outer edges 50a and 50b, the light from the light emitting unit 58a is blocked by the worker, and the sensors (58a and 58b) detect the worker located on the outer edges 50a and 50b. The sensors (58a and 58b) may detect not only the worker located on the outer edges 50a and 50b, but also the sagger 2 located on the outer edges 50a and 50b.

[0035] The sensor (more specifically, the light receiving unit 58b) outputs the detection result to the control unit (not shown) of the circulating conveying device 30. When the control unit of the circulating conveying device 30 obtains the detection result that an object (e.g., a worker, etc.) is located on the outer edges 50a, 50b, it stops the conveying of the sack 2 by the conveying rollers 32. Specifically, it stops the driving of the driving device 34 and stops the rotation of the conveying rollers 32. This stops the conveying of the sack 2. When a worker enters the first conveying path 50, it is possible to prevent the sack 2 being conveyed from coming into contact with the worker by stopping the conveying of the sack 2 by the conveying rollers 32. When the control unit of the circulating conveying device 30 obtains the detection result that an object (e.g., a worker, etc.) is not located on the outer edges 50a, 50b, it causes the conveying rollers 32 to convey the sack 2. This makes it possible to automatically resume the conveying of the sack 2 when the state in which the worker has entered the first conveying path 50 is resolved.

[0036] On the first transport path 50, a reflecting plate 60, an imaging device 62, and a suction nozzle 64 are installed.

[0037] The reflecting plate 60 is disposed between one of the two outer edges 50a, 50b (the outer edge 50a in FIG. 5) and the sagger 2 being transported on the transport rollers 32. In this embodiment, the first transport path 50 is configured so that an operator can view the first transport path 50 from the -Y direction side. The reflecting plate 60 is disposed near the outer edge 50b (i.e., the outer edge 50b on the -Y direction side) which is located away from the position where the operator views the first transport path 50 (the -Y direction side in this embodiment).

[0038] The reflector 60 is arranged so as to reflect the side surface 4a of the sack 2 on the reflector 60 side, which is conveyed on the first conveying path 50, toward the position where the worker sees the first conveying path 50 (in this embodiment, the -Y direction side). By arranging the reflector 60, the worker can directly see the side surface 4b of the sack 2 opposite to the side surface 4a on the reflector 60 side, and can also see the side surface 4a of the sack 2 on the reflector 60 side through the reflector 60. Therefore, the worker can simultaneously check both side surfaces 4a, 4b parallel to the conveying direction of the sack 2 from one of the two outer edges 50a, 50b (the outer edge 50a in FIG. 5). By installing the reflector 60 on the first conveying path 50, the worker can check the part of the sack 2 that is blind spot for the worker. In this embodiment, two reflectors 60 are arranged. By disposing a plurality of reflecting plates 60 (two in this embodiment) on the first transport path 50, it becomes easier to check the entire sagger 2 from one side of the two outer edges 50a, 50b. The number of reflecting plates 60 to be installed is not limited, and may be one, or three or more.

[0039] The imaging device 62 is disposed so as to capture an image of the sack 2 being conveyed along the first conveying path 50. A plurality of imaging devices 62 (two in this embodiment) are disposed along the first conveying path 50. As shown in FIG. 5, the imaging device 62 is disposed near the outer edge 50a (i.e., the outer edge 50a on the +Y direction side) located away from the position where the worker views the first conveying path 50 (the -Y direction side in this embodiment), and captures an image of the sack 2 from the outer edge 50a side. As described above, since the worker views the first conveying path 50 from the outer edge 50b side, the outer edge 50b side of the sack 2 can be directly viewed, while the outer edge 50a side of the sack 2 is difficult to view. By capturing an image of the sack 2 from the outer edge 50a side with the imaging device 62, it is possible to check the blind spot of the sack 2 from the worker. 6, the imaging device 62 captures an image of the sack 2 conveyed on the first conveying path 50 from above. This makes it easier to check the inside of the sack 2. The number of imaging devices 62 to be installed is not limited, and may be one, or three or more.

[0040] The suction nozzle 64 is used by the worker to clean the sack 2 transported on the first transport path 50. The suction nozzle 64 is connected to the dust collector 66. As described above, the inside or outer surface of the sack 2 transported on the first transport path 50 may have a processing object attached thereto. When the processing object is attached to the sack 2 transported on the first transport path 50, the worker finds that the processing object is attached to the sack 2 by directly looking at the sack 2, looking at the sack 2 through the reflector 60, or checking the state of the sack 2 from the image captured by the image capture device 62. In such a case, the worker uses the suction nozzle 64 to suck the processing object attached to the sack 2. This makes it possible to remove the processing object attached to the sack 2 on the first transport path 50, and the sack 2 from which the processing object has been removed can be transported to the supply device 40.

[0041] Points to note regarding the heat treatment system 1 described in the embodiment will be described below. The circulating transport device 30 in the embodiment is an example of the "transport device", and the door 56 is an example of the "blocking section".

[0042] Although specific examples of the technology disclosed in this specification have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. Furthermore, the technical elements described in this specification or drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technology exemplified in this specification or drawings achieves multiple objectives simultaneously, and achieving one of the objectives itself has technical utility. [Explanation of symbols]

[0043] 1: Heat treatment system 2: Box 10: Heat treatment furnace 30: Circulation transport device 32: Transport roller 34: Drive unit 40: Feeding device 42: Recovery device 44:Cleaning device 46: Crack detection device 50: First transport route 52: Second transport route 54: Food 56: Door 58a: Light-emitting part of the sensor 58b: Light receiving part of the sensor 60:Reflector 62: Imaging device 64: Suction nozzle

Claims

1. a heat treatment furnace having an inlet and an outlet, for heat-treating the workpiece contained in the sagger while transporting the sagger from the inlet to the outlet; a conveying device that conveys the sagger discharged from the discharge outlet of the heat treatment furnace to the discharge inlet of the heat treatment furnace; a recovery device that is provided on a transport path of the transport device and recovers the workpiece that has been heat-treated in the heat treatment furnace from the sagger; a supply device that is provided on the transport path of the transport device between the recovery device and the entrance and that supplies the workpiece before heat treatment to the sagger in which the workpiece is not contained; A hood that covers the conveying path, The transport path is a first transport path provided in at least a portion of an area between the recovery device and the supply device; a second transport path provided in a region of the transport path other than a region in which the first transport path is provided, A heat treatment system, wherein the hood is provided on the second transport path and is not provided on the first transport path.

2. 2. The heat treatment system according to claim 1, wherein the hood comprises an opening provided between the first transport path and the second transport path, and a blocking portion provided at the opening to block a space inside the hood from a space outside the hood.

3. the first conveying path has an outer edge parallel to a conveying direction of the saggers; The thermal processing system of claim 1 , further comprising a sensor for detecting whether an object is located on the outer edge.

4. The heat treatment system of claim 3 , wherein the transport device stops transporting the sagger when the sensor detects the object, and transports the sagger by the transport device when the sensor does not detect the object.

5. the first conveying path has an outer edge parallel to a conveying direction of the saggers; The sagger has a first side located on the outer edge side and a second side located opposite the first side, The heat treatment system of claim 1 , further comprising a reflector arranged on the second side of the sagger transported along the first transport path, and reflecting the second side when the sagger is viewed from the first side.

6. The heat treatment system according to claim 1 , further comprising an imaging device provided on the first transport path, for capturing an image of the sagger transported on the first transport path.

7. The heat treatment system according to claim 6 , wherein the imaging device is a plurality of imaging devices arranged on the first transport path.

8. The heat treatment system according to claim 1 , further comprising a cleaning device provided in the first transport path for cleaning the saggers transported through the first transport region.

9. The heat treatment system according to claim 8 , wherein the cleaning device is a suction nozzle that sucks up deposits adhering to the sagger.

Images