Heating furnace

Abstract

Provided is a heating furnace that addresses the problem of a long path length of a gas line and a large overall size of the heating furnace. The heating furnace (100) includes: a main body portion (10) having a heat treatment space (11) for performing heat treatment of a processed object; a gas supply portion (20) that supplies a gas required for the heat treatment to the heat treatment space of the main body portion; a suction and discharge portion (30) having a gas line (31) connected to the main body portion, which repeatedly performs suction of the gas from the heat treatment space to the gas line and discharge of the suctioned gas to the heat treatment space; and a heat storage body (40) disposed inside the gas line, which is capable of heat exchange. The gas line is configured such that, when the gas is suctioned and discharged via the gas line, the inner product of a unit vector in the direction of travel of the gas discharged from the gas line to the heat treatment space and a unit vector in the direction of travel of the gas suctioned from the heat treatment space to the gas line becomes 0 or less.

Description

TECHNICAL FIELD

[0001] The present application relates to a heating furnace. BACKGROUND

[0002] A heating furnace that supplies gas into a furnace and performs heat treatment of a processed object is known.

[0003] As one of such heating furnaces, a heating furnace is disclosed in Patent Literature 1, in which gas in a furnace is introduced to an outside-furnace circulation path by a circulation fan, and the gas introduced to the outside-furnace circulation path is returned to the furnace again. In this heating furnace, a heat storage body is provided at a position outside the furnace in the outside-furnace circulation path. The gas introduced from the furnace to the outside-furnace circulation path is made low-temperature by heat exchange with the heat storage body, and the gas returned to the furnace is made high-temperature by heat exchange with the heat storage body and then ejected into the furnace. According to such a structure, in the heating furnace described in Patent Literature 1, a high-temperature and strong circulation flow can be supplied to the furnace.

[0004] PRIOR ART LITERATURE

[0005] PATENT LITERATURE

[0006] Patent Literature 1: Japanese Patent Application Laid-Open No. 9-178112

[0007] In the heating furnace described in Patent Literature 1, of a pair of side walls opposing each other, one side wall is connected to one end of the outside-furnace circulation path, and the other side wall is connected to the other end of the outside-furnace circulation path. Therefore, the path length of the outside-furnace circulation path becomes long, and the size of the entire heating furnace becomes large. SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] The present application has been made to solve the above problems, and has an object to provide a heating furnace that can shorten the path length of a gas line connected to a main body portion of the heating furnace and reduce the size of the entire heating furnace.

[0010] MEANS OF SOLVING THE PROBLEM

[0011] The heating furnace of the present application is characterized by comprising:

[0012] a main body portion having a heat treatment space for performing heat treatment of a processed object, and a heating portion disposed in the heat treatment space;

[0013] a gas supply portion that supplies gas required for the heat treatment to the heat treatment space of the main body portion;

[0014] A suction ejection section, having a gas conduit connected to the main body, repeatedly performs the functions of suctioning gas from the heat treatment space into the gas conduit and ejecting the gas suctioned into the gas conduit back into the heat treatment space; and

[0015] A heat storage element, disposed inside the gas pipeline, enables heat exchange.

[0016] The gas pipeline is configured such that, during the attraction and ejection of gas via the gas pipeline, the dot product of the unit vector along the direction of travel of the gas ejected from the gas pipeline into the heat treatment space and the unit vector along the direction of travel of the gas attracted from the heat treatment space into the gas pipeline is less than 0.

[0017] Invention Effects

[0018] In the heating furnace of the present invention, the gas pipeline is configured such that the dot product of the unit vector along the travel direction of the gas ejected from the gas pipeline into the heat treatment space and the unit vector along the travel direction of the gas attracted from the heat treatment space into the gas pipeline is less than 0. By configuring it in this way, the path length of the gas pipeline can be shortened, and the overall size of the heating furnace can be reduced. Attached Figure Description

[0019] Figure 1 This is a schematic cross-sectional view showing the structure of the heating furnace in the first embodiment.

[0020] Figure 2 It schematically shows a cut along line II-II. Figure 1 The diagram shows a cross-sectional view of the structure of the heating furnace.

[0021] Figure 3 This is a schematic perspective view of the structure of a cooler that uses a small heat exchanger.

[0022] Figure 4(a) is a diagram illustrating the operation of drawing gas from the first suction nozzle of the gas pipeline and ejecting gas from the second suction nozzle in the heating furnace of the first embodiment. Figure 4(b) is a diagram illustrating the operation of drawing gas from the second suction nozzle of the gas pipeline and ejecting gas from the first suction nozzle.

[0023] Figure 5 This is a schematic cross-sectional view showing the structure of the heating furnace in the second embodiment.

[0024] Figure 6(a) is a diagram illustrating the operation of drawing gas from the first suction nozzle of the gas pipeline and ejecting gas from the second suction nozzle in the heating furnace of the second embodiment. Figure 6(b) is a diagram illustrating the operation of drawing gas from the second suction nozzle of the gas pipeline and ejecting gas from the first suction nozzle.

[0025] Figure 7 This is a schematic cross-sectional view showing the structure of the heating furnace in the third embodiment.

[0026] Figure 8 This schematically shows the view from the direction of arrow Y1. Figure 7 The diagram shows the structure of the heating furnace.

[0027] Figure 9 This is a schematic cross-sectional view showing the structure of the heating furnace in the fourth embodiment.

[0028] Figure 10 This is a schematic cross-sectional view showing the structure of the heating furnace in the fifth embodiment.

[0029] Figure 11 This is a diagram showing the relationship between the unit vector of the gas ejected from the first extension of the gas pipeline into the heat treatment space via the first suction nozzle in the heating furnace of the fifth embodiment and the unit normal vector extending relative to the side of the plate on which the workpiece is placed, facing the workpiece.

[0030] Figure 12 This is a schematic cross-sectional view showing the structure of the heating furnace in the sixth embodiment.

[0031] Figure 13 This is an enlarged cross-sectional view of the area near the first suction nozzle in the gas pipeline in the heating furnace of the sixth embodiment.

[0032] Figure 14 This is a schematic cross-sectional view showing the structure of the heating furnace in the seventh embodiment.

[0033] Figure 15 This is a schematic cross-sectional view showing the structure of the heating furnace in the eighth embodiment.

[0034] Explanation of reference numerals in the attached figures

[0035] 1: The object being processed;

[0036] 10: Main body;

[0037] 11: Heat treatment space;

[0038] 12: Heating section;

[0039] 13: Drive roller;

[0040] 14: Gas supply port;

[0041] 15: Gas exhaust port;

[0042] 16: First suction nozzle;

[0043] 17: Second suction nozzle;

[0044] 20: Gas Supply Department;

[0045] 30: Suction ejection section;

[0046] 31: Gas pipeline;

[0047] 31a: First extension;

[0048] 31a1: First horizontal section;

[0049] 31a2: First vertical part;

[0050] 31b: Second extension;

[0051] 31b1: Second horizontal section;

[0052] 31b2: Second vertical part;

[0053] 31c: Third extension;

[0054] 32a: First fan;

[0055] 32b: Second fan;

[0056] 32c: Third fan;

[0057] 32d: 4th fan;

[0058] 33a: First cooler;

[0059] 33b: Second cooler;

[0060] 34a: First vaporizer;

[0061] 34b: Second vaporizer;

[0062] 40a: First heat storage body;

[0063] 40b: Second heat storage body;

[0064] 100, 100A, 100B, 100C, 100D, 100E, 100F, 100G: Heating furnace;

[0065] L1: Gas flow path;

[0066] L2: Refrigerant flow path. Detailed Implementation

[0067] The following describes embodiments of the present invention, and the features of the present invention will be specifically explained.

[0068] <First Implementation>

[0069] Figure 1 This is a schematic cross-sectional view showing the structure of the heating furnace 100 in the first embodiment. Figure 2 It schematically shows a cut along line II-II. Figure 1 A cross-sectional view of the structure of the heating furnace 100 shown. Wherein, in Figure 2 The driving roller 13, which will be described later, is omitted in the text.

[0070] Here, the heating furnace 100 is described as a roller hearth furnace. A roller hearth furnace is a continuous heating furnace in which multiple drive rollers 13 are arranged at certain intervals along the travel direction inside the furnace, and the workpiece 1 is conveyed on the drive rollers 13. Figure 1 The diagram shows a cross-section of the heating furnace 100 when cut with a plane orthogonal to the conveying direction of the workpiece 1. However, the heating furnace 100 is not limited to a roller hearth furnace, but may be other types of heating furnaces such as intermittent heating furnaces.

[0071] The heating furnace 100 includes a main body 10, a gas supply unit 20, a suction ejection unit 30, and a heat storage body 40.

[0072] The main body 10 has a heat treatment space 11 for heat treatment of the workpiece 1, and a heating unit 12 disposed within the heat treatment space 11. The shape and size of the main body 10 are not particularly limited. The heating unit 12 is, for example, a heater capable of heating to approximately 1300°C. In this embodiment, a drive roller 13 is disposed in the heat treatment space 11, and the heating unit 12 is disposed on the side opposite to the workpiece 1 and the drive roller 13, i.e., above the workpiece 1, such that the workpiece 1 is located between the drive roller 13 and the heating unit 12. However, the location of the heating unit 12 is not limited to the position opposite to the workpiece 1 and the drive roller 13.

[0073] In this embodiment, such as Figure 1 As shown, the main body 10 includes four furnace walls: a first side wall 10a, a second side wall 10b, a bottom wall 10c, and a top wall 10d. The first side wall 10a and the second side wall 10b, as well as the bottom wall 10c and the top wall 10d, are respectively positioned opposite each other in a direction orthogonal to the conveying direction of the workpiece 1. Furthermore, as... Figure 2As shown, both ends of the conveying direction of the processed object 1 are open and connected to the loading and unloading outlets for the processed object 1. The furnace wall of the main body 10, which includes the first side wall 10a, the second side wall 10b, the bottom wall 10c, and the top wall 10d, contains, for example, heat-insulating material.

[0074] There is no limitation on the type of material 1 to be processed as the object of heat treatment; for example, it is an unfired ceramic body used to manufacture sheet-shaped ceramic electronic components such as multilayer ceramic capacitors. In this embodiment, a plate 2 carrying a plurality of materials 1 to be processed is conveyed on a drive roller 13. The plate 2 may contain ceramic, for example.

[0075] The gas supply unit 20 supplies the gas required for heat treatment to the heat treatment space 11 of the main body 10. A gas supply port 14 is provided in the main body 10, and the gas supply unit 20 supplies the gas required for heat treatment to the heat treatment space 11 through the gas supply port 14.

[0076] In addition, a gas outlet 15 is provided in the main body 10 for discharging unwanted gases, so that the pressure in the heat treatment space 11 remains constant.

[0077] The suction ejection section 30 has a gas pipe 31 connected to the main body 10, and repeatedly performs the suction of gas from the heat treatment space 11 to the gas pipe 31 and the ejection of the gas drawn into the gas pipe 31 into the heat treatment space 11. In this embodiment, the gas drawn into the gas pipe 31 by the suction ejection section 30 and ejected into the heat treatment space 11 is a gas with the same composition as the gas in the heat treatment space 11.

[0078] The gas conduit 31 is configured such that, during gas attraction and ejection, the dot product of the unit vector along the travel direction of the gas ejected from the gas conduit 31 into the heat treatment space 11 and the unit vector along the travel direction of the gas attracted from the heat treatment space 11 into the gas conduit 31 is less than 0. To achieve this structure, in the heating furnace 100 of this embodiment, as follows... Figure 2 As shown, one end of the gas pipeline 31 and the other end are connected to the same side wall of the main body 10, and more specifically to the first side wall 10a.

[0079] However, one end of the gas pipe 31 can be connected to the second side wall 10b, or to the bottom wall 10c or the top wall 10d. Alternatively, one end of the gas pipe 31 can be connected to one of the two side walls 10a and 10b of the main body 10, and the other end can be connected to the bottom wall 10c or the top wall 10d of the main body 10.

[0080] One end of the gas pipe 31 faces the heat treatment space 11, forming the first suction nozzle 16. The other end of the gas pipe 31 faces the heat treatment space 11, forming the second suction nozzle 17.

[0081] like Figure 2 As shown, the gas conduit 31 in this embodiment has a U-shaped shape. Specifically, the gas conduit 31 includes a first extension 31a extending from a first suction nozzle 16 at one end toward the outer side of the main body 10, a second extension 31b extending from a second suction nozzle 17 at the other end toward the outer side of the main body 10, and a third extension 31c connecting the first extension 31a and the second extension 31b. The first extension 31a, the second extension 31b, and the third extension 31c each have a straight shape. The first extension 31a and the second extension 31b extend parallel to each other in a direction orthogonal to the first sidewall 10a, and the third extension 31c extends in a direction parallel to the first sidewall 10a. However, the shape of the gas conduit 31 is not limited to a U-shaped shape.

[0082] The first extension 31a, the second extension 31b, and the third extension 31c are all located at the same height. That is, the gas pipe 31 is installed on the main body 10, allowing the gas to move horizontally.

[0083] In this way, the gas pipe 31 is configured such that, during gas attraction and ejection, the dot product of the unit vector along the direction of travel of the gas ejected from the gas pipe 31 into the heat treatment space 11 and the unit vector along the direction of travel of the gas attracted from the heat treatment space 11 into the gas pipe 31 is less than 0. This shortens the path length of the gas pipe 31, allowing for a smaller structure of the heating furnace 100. The shorter path length of the gas pipe 31 increases the freedom of its placement and simplifies its installation. Furthermore, the shorter path length of the gas pipe 31 suppresses heat loss to the outside of the flow path as the gas flows through it, thereby improving thermal efficiency.

[0084] Furthermore, in a structure where one end of a gas pipe is connected to one of a pair of opposing sidewalls of the main body and the other end of a gas pipe is connected to the other side, the dot product of the unit vector along the direction of travel of the gas ejected from the gas pipe into the heat treatment space and the unit vector along the direction of travel of the gas attracted from the heat treatment space into the gas pipe becomes positive.

[0085] The suction ejection unit 30 in this embodiment includes: a first fan 32a disposed in the first extension 31a of the gas conduit 31; and a second fan 32b disposed in the second extension 31b of the gas conduit 31. The first fan 32a and the second fan 32b can each be of any configuration as long as they are capable of delivering airflow. In the following description, the first fan 32a and the second fan 32b are sometimes collectively referred to as fan 32.

[0086] The first fan 32a is configured such that, when driven, gas flows from the first extension 31a to the third extension 31c of the gas conduit 31. That is, when the first fan 32a is driven, gas is drawn from the heat treatment space 11 to the first extension 31a of the gas conduit 31 via the first suction nozzle 16. At this time, the second fan 32b is in a non-driven state. The gas drawn from the heat treatment space 11 to the first extension 31a of the gas conduit 31 passes through the third extension 31c and the second extension 31b, and is ejected from the second suction nozzle 17 into the heat treatment space 11.

[0087] The second fan 32b is configured such that, when driven, gas flows from the second extension 31b of the gas conduit 31 to the third extension 31c. That is, when the second fan 32b is driven, gas is drawn from the heat treatment space 11 to the second extension 31b of the gas conduit 31 via the second suction nozzle 17. At this time, the first fan 32a is in a non-driven state. The gas drawn from the heat treatment space 11 to the second extension 31b of the gas conduit 31 passes through the third extension 31c and the first extension 31a, and is ejected from the first suction nozzle 16 into the heat treatment space 11.

[0088] Alternatively, the first fan 32a can be configured such that gas flows from the first extension 31a of the gas conduit 31 to the heat treatment space 11 when it is driven, and the second fan 32b can be configured such that gas flows from the second extension 31b of the gas conduit 31 to the heat treatment space 11 when it is driven. In this case, if the first fan 32a is driven, gas is drawn from the heat treatment space 11 to the second extension 31b of the gas conduit 31 via the second suction nozzle 17, and gas is ejected from the first suction nozzle 16 into the heat treatment space 11. Furthermore, if the second fan 32b is driven, gas is drawn from the heat treatment space 11 to the first extension 31a of the gas conduit 31 via the first suction nozzle 16, and gas is ejected from the second suction nozzle 17 into the heat treatment space 11.

[0089] As described above, the gas ejected from the heat treatment space 11 of the main body 10 via the suction ejection section 30 is gas drawn from the heat treatment space 11 and has the same composition as the gas inside the heat treatment space 11. That is, the gas drawn from the heat treatment space 11 through the first suction ejection port 16 into the gas pipeline 31 is not mixed with other gases, air, etc., and is directly ejected into the heat treatment space 11 via the second suction ejection port 17. Similarly, the gas drawn from the heat treatment space 11 through the second suction ejection port 17 into the gas pipeline 31 is not mixed with other gases, air, etc., and is directly ejected into the heat treatment space 11 via the first suction ejection port 16. Here, the gas drawn from the heat treatment space 11 without being mixed with other gases, air, etc., is defined as a gas having the same composition as the gas inside the heat treatment space 11.

[0090] The heating furnace 100 in this embodiment includes a cooler 33 disposed in the gas pipeline 31 for cooling the gas drawn from the heat treatment space 11 and passing through the heat storage body 40 (described later). The cooler 33 includes: a first cooler 33a disposed in the first extension 31a of the gas pipeline 31; and a second cooler 33b disposed in the second extension 31b of the gas pipeline 31. The first cooler 33a is disposed between the first heat storage body 40a (described later) and the first fan 32a. The second cooler 33b is disposed between the second heat storage body 40b (described later) and the second fan 32b.

[0091] The first cooler 33a cools the gas drawn from the heat treatment space 11 into the first extension 31a of the gas pipe 31 and passing through the first heat storage body 40a (described later). As an example, the gas drawn from the heat treatment space 11 into the first extension 31a of the gas pipe 31 via the first suction outlet 16 is cooled to approximately 100°C by the first heat storage body 40a. The gas cooled by the first heat storage body 40a is further cooled to below 50°C by the first cooler 33a. This prevents thermal damage to the high-temperature gas flowing into the first fan 32a.

[0092] The second cooler 33b cools the gas drawn from the heat treatment space 11 into the second extension 31b of the gas pipe 31 and passing through the second heat storage body 40b (described later). As an example, the gas drawn from the heat treatment space 11 into the second extension 31b of the gas pipe 31 via the second suction outlet 17 is cooled to approximately 100°C by the second heat storage body 40b. The gas cooled by the second heat storage body 40b is further cooled to below 50°C by the second cooler 33b. This prevents thermal damage to the high-temperature gas flowing into the second fan 32b.

[0093] Furthermore, by providing the first cooler 33a and the second cooler 33b, the temperature distribution of the first heat storage body 40a and the second heat storage body 40b can be maintained in a balanced state. That is, without the first cooler 33a and the second cooler 33b, the temperature of the first heat storage body 40a and the second heat storage body 40b rises during the repeated suction of gas from the heat treatment space 11 to the gas pipe 31 and the ejection of gas from the gas pipe 31 to the heat treatment space 11. In this case, the temperature of the gas cooled by the first heat storage body 40a and the gas cooled by the second heat storage body 40b may greatly exceed 100°C.

[0094] However, in the heating furnace 100 of this embodiment, a first cooler 33a and a second cooler 33b are provided, so the rise in temperature distribution of the first heat storage body 40a and the second heat storage body 40b can be suppressed, and the temperature of the gas passing through the first heat storage body 40a and the gas passing through the second heat storage body 40b can be suppressed from greatly exceeding 100°C.

[0095] As described below, the first cooler 33a and the second cooler 33b are configured such that the cooling function of the cooler disposed in the extension of the first extension 31a and the second extension 31b of the gas pipeline 31 is turned on, and the cooling function of the cooler disposed in the extension of the gas ejection path is turned off.

[0096] For example, known heat exchangers can be used as the first cooler 33a and the second cooler 33b. Figure 3 This is a perspective view schematically showing the structure of a cooler 33 (first cooler 33a, second cooler 33b) that uses a small heat exchanger as one of the heat exchangers. Figure 3 As shown, the cooler 33 has a structure in which a gas flow path L1 carrying high-temperature gas and a refrigerant flow path L2 are alternately stacked. The gas flow path L1 and the refrigerant flow path L2 are configured to be orthogonal to each other. Multiple heat sinks are provided in the gas flow path L1 and the refrigerant flow path L2, and heat exchange occurs between the gas flowing through the gas flow path L1 and the refrigerant flowing through the refrigerant flow path L2.

[0097] In addition, Figure 3 Although the diagram shows a structure in which gas flow path L1 and refrigerant flow path L2 are each provided with two layers, the number of layers in gas flow path L1 and refrigerant flow path L2 is not limited to 2.

[0098] As a cooler 33, by using a heat exchanger that alternately stacks a gas flow path L1 for flowing gas and a refrigerant flow path L2 for flowing refrigerant, the required gas can be cooled using a small-sized cooler, and the structure of the heating furnace 100 can be made compact.

[0099] The cooling function of the first cooler 33a will be explained. In the refrigerant flow path L2, a refrigerant used to cool the gas flowing through the gas flow path L1 flows. The refrigerant is, for example, cold air. For example, a cooling fan is installed upstream of the refrigerant flow path L2, causing cold air to flow into the refrigerant flow path L2. In the gas flow path L1, the gas that has passed through the first heat storage body 40a flows.

[0100] As an example, suppose that gas at approximately 100°C, having passed through the first heat storage body 40a, flows into the gas flow path L1 of the first cooler 33a at a flow rate of 30 L / min. In the refrigerant flow path L2 of the first cooler 33a, if cold air at a flow rate of 30–120 L / min flows through it, the gas flowing through gas flow path L1 will be cooled to approximately 50°C. The same applies to the second cooler 33b.

[0101] Furthermore, the first cooler 33a and the second cooler 33b are only required to cool the gas, and are not limited to heat exchangers with alternating layers of a gas flow path L1 for flowing gas and a refrigerant flow path L2 for flowing refrigerant. In addition, cooler 33 can be omitted as long as the gas is sufficiently cooled by the heat storage body 40.

[0102] The heat storage body 40 has a heat-exchangeable structure capable of repeatedly storing and dissipating heat, and is disposed inside the gas pipeline 31. In this embodiment, the heat storage body 40 is disposed inside the gas pipeline 31 in the portion inside the main body 10, specifically in the region penetrating the main body 10. In this embodiment, the heat storage body 40 includes: a first heat storage body 40a disposed in the first extension 31a of the gas pipeline 31; and a second heat storage body 40b disposed in the second extension 31b. Although the first heat storage body 40a and the second heat storage body 40b may protrude into the region outside the main body 10 inside the gas pipeline 31, they do not protrude within the heat treatment space 11 of the main body 10.

[0103] In addition, Figure 1 as well as Figure 2 In this configuration, the heat storage element 40 is disposed inside the gas pipeline 31, penetrating the entire area of ​​the main body 10, but it may also be disposed only in a portion of the main body 10. Alternatively, the heat storage element 40 may be disposed inside the gas pipeline 31 on the outside of the main body 10.

[0104] The heat storage body 40 only needs to have a heat exchange-capable structure, such as a cylindrical body with multiple honeycomb-shaped unit holes formed of ceramic, or a cylindrical body that houses multiple spheres containing ceramic inside. Furthermore, the honeycomb-shaped units are generally hexagonal, but can also be quadrilateral, triangular, or other shapes other than hexagonal. In addition, the heat storage body 40 can also be made of materials other than ceramic.

[0105] Here, the suction and ejection of gas via gas conduit 31 will be explained. As shown in FIG4(a), if the first fan 32a is driven and the second fan 32b is set to a non-driven state, the gas in the heat treatment space 11 of the main body 10 is drawn from the first suction outlet 16 to the first extension 31a of gas conduit 31. The temperature of the gas in the heat treatment space 11 is set to approximately 1200°C, for example.

[0106] At this time, the cooling function of the first cooler 33a, which is located in the first extension 31a that serves as the gas suction flow path, is set to ON, and the cooling function of the second cooler 33b, which is located in the second extension 31b that serves as the gas ejection flow path, is set to OFF. The gas drawn from the heat treatment space 11 through the first suction nozzle 16 passes through the first heat storage body 40a located in the first extension 31a of the gas pipeline 31, but heat exchange occurs at this time, and the temperature drops to about 100°C. As a result, the first heat storage body 40a is heated and becomes a high-temperature state.

[0107] The gas passing through the first heat storage body 40a is cooled to a temperature below 50°C by passing through the gas flow path L1 of the first cooler 33a. The gas passing through the first cooler 33a flows into the second extension 31b through the third extension 31c of the gas pipe 31 and is introduced into the second heat storage body 40b. At this time, the cooling function of the second cooler 33b is turned off, thus preventing the gas introduced into the second heat storage body 40b from being cooled to a degree higher than necessary.

[0108] The second heat storage body 40b has been heated to a high temperature by the previous heat exchange. Therefore, the gas passes through the second heat storage body 40b and is heated to a temperature of about 1150°C, which is close to the temperature inside the heat treatment space 11, through heat exchange. The gas that has passed through the second heat storage body 40b is ejected from the second suction nozzle 17 into the heat treatment space 11 and reaches the surfaces of the multiple objects 1 to be treated on the plate 2.

[0109] In Figure 4(a), arrows indicate the direction of the gas flow when gas is drawn from the heat treatment space 11 into the gas pipeline 31 via the first suction nozzle 16 and ejected from the heat treatment space 11 via the second suction nozzle 17. As shown in Figure 4(a), the direction of the gas flow drawn from the heat treatment space 11 into the gas pipeline 31 via the first suction nozzle 16 and the direction of the gas flow ejected from the gas pipeline 31 into the heat treatment space 11 via the second suction nozzle 17 are opposite to each other. Therefore, during the drawing and ejection of gas through the gas pipeline 31, the dot product of the unit vector along the direction of travel of the gas ejected from the gas pipeline 31 into the heat treatment space 11 and the unit vector along the direction of travel of the gas drawn from the heat treatment space 11 into the gas pipeline 31 becomes negative.

[0110] Furthermore, since gas is ejected from gas pipe 31 toward the second suction nozzle 17 along the direction of gas pipe 31's extension, in the example shown in FIG4(a), the unit vector along the direction of travel of the gas ejected from gas pipe 31 toward heat treatment space 11 means the unit vector along the direction of travel of the second extension 31b of gas pipe 31 toward the second suction nozzle 17. Moreover, since the gas attracted to gas pipe 31 flows along the direction of travel of gas pipe 31's extension, in the example shown in FIG4(a), the unit vector along the direction of travel of the gas attracted from heat treatment space 11 toward gas pipe 31 means the unit vector along the direction of travel of the first extension 31a of gas pipe 31 from the first suction nozzle 16.

[0111] Next, as shown in Figure 4(b), if the second fan 32b is driven and the first fan 32a is set to a non-driven state, the gas in the heat treatment space 11 of the main body 10 is drawn from the second suction nozzle 17 to the second extension 31b of the gas pipe 31. At this time, the cooling function of the second cooler 33b, which is disposed in the second extension 31b that becomes the gas suction flow path, is turned on, and the cooling function of the first cooler 33a, which is disposed in the first extension 31a that becomes the gas ejection flow path, is turned off. The gas drawn from the heat treatment space 11 passes through the second heat storage body 40b disposed in the second extension 31b of the gas pipe 31, but heat exchange occurs at this time, and the temperature drops to about 100°C. As a result, the second heat storage body 40b is heated and becomes a high-temperature state.

[0112] The gas passing through the second heat storage body 40b is cooled to a temperature below 50°C by passing through the gas flow path L1 of the second cooler 33b. The gas passing through the second cooler 33b flows into the first extension 31a through the third extension 31c of the gas pipe 31 and is introduced into the first heat storage body 40a. At this time, the cooling function of the first cooler 33a is turned off, thus preventing the gas introduced into the first heat storage body 40a from being cooled to a degree higher than necessary.

[0113] The first heat storage body 40a is heated to a high temperature by storing heat from the previous heat exchange. Therefore, the gas passes through the first heat storage body 40a and is heated to a temperature of about 1150°C, which is close to the temperature inside the heat treatment space 11, through heat exchange. The gas that has passed through the first heat storage body 40a is ejected from the first suction nozzle 16 into the heat treatment space 11 and reaches the surfaces of the multiple objects 1 to be treated on the plate 2.

[0114] In Figure 4(b), arrows indicate the direction of the gas flow when gas is drawn from the heat treatment space 11 into the gas pipeline 31 via the second suction nozzle 17 and ejected from the heat treatment space 11 via the first suction nozzle 16. As shown in Figure 4(b), the direction of the gas flow drawn from the heat treatment space 11 into the gas pipeline 31 via the second suction nozzle 17 and the direction of the gas flow ejected from the gas pipeline 31 into the heat treatment space 11 via the first suction nozzle 16 are opposite to each other. Therefore, during the drawing and ejection of gas through the gas pipeline 31, the dot product of the unit vector along the direction of travel of the gas ejected from the gas pipeline 31 into the heat treatment space 11 and the unit vector along the direction of travel of the gas drawn from the heat treatment space 11 into the gas pipeline 31 becomes negative.

[0115] Furthermore, since gas is ejected from gas pipe 31 toward the first suction nozzle 16 along the direction of gas pipe 31's extension, in the example shown in FIG4(b), the unit vector along the direction of travel of the gas ejected from gas pipe 31 toward heat treatment space 11 means the unit vector along the direction of travel of the first extension 31a of gas pipe 31 toward the first suction nozzle 16. Moreover, since the gas attracted to gas pipe 31 flows along the direction of travel of gas pipe 31's extension, in the example shown in FIG4(b), the unit vector along the direction of travel of the gas attracted from heat treatment space 11 toward gas pipe 31 means the unit vector along the direction of travel of the second extension 31b of gas pipe 31 from the second suction nozzle 17.

[0116] Here, the actions of drawing in and ejecting gas generated by the drive of the first fan 32a and the actions of drawing in and ejecting gas generated by the drive of the second fan 32b are respectively defined as "one cycle".

[0117] By repeatedly driving the first fan 32a and the second fan 32b at regular intervals, the operation of drawing gas from the heat treatment space 11 through one of the first suction nozzle 16 and the second suction nozzle 17 and ejecting gas into the heat treatment space 11 through the other can be repeatedly performed. Thus, in the heating furnace 100 of this embodiment, by switching the driving and non-driving of the first fan 32a and the second fan 32b, the drawing and ejection of gas through the first suction nozzle 16 and the second suction nozzle 17 can be switched, allowing the switching of gas drawing and ejection without the use of valves. This makes the structure of the heating furnace 100 more compact and reduces costs.

[0118] Furthermore, the first fan 32a and the second fan 32b can be controlled to arbitrary outputs, for example, via PWM control. Therefore, for example, the first fan 32a and the second fan 32b can be controlled separately to repeatedly increase and decrease the airflow within a cycle. By repeatedly increasing and decreasing the airflow, a large gas ejection velocity can be obtained instantaneously, thus generating an entrainment phenomenon within the heat treatment space 11, where the high-temperature gas entrained into the ejected flow increases. Consequently, the temperature of the gas ejected into the heat treatment space 11 and flowing near the workpiece 1 becomes closer to the temperature of the gas within the heat treatment space 11, thereby making the heat treatment reaction of each workpiece 1 more uniform.

[0119] Here, the gas temperature at various points was investigated when the airflow of fan 32 was changed. The heat storage body 40 used was a cylinder with multiple honeycomb-shaped unit holes of 400 CPSI each, a diameter of 30 mm, and a length of 200 mm. Furthermore, with the furnace temperature at 800°C, gas was repeatedly drawn in and ejected at 10-second cycles, and the temperatures of the gas ejected from the heat storage body 40 into the heat treatment space 11, the gas drawn from the heat treatment space 11 through the heat storage body 40, and the gas flowing into fan 32 through the heat storage body 40 were investigated. The results are shown in Table 1.

[0120] [Table 1]

[0121]

[0122] As shown in Table 1, the airflow of fan 32 was changed to 14.4 L / min, 18.0 L / min, 24.0 L / min, 30.0 L / min, 37.2 L / min, and 44.4 L / min. Furthermore, a simplified cooler was used instead of the first cooler 33a and the second cooler 33b, and the gas temperature was measured when both were operating with the cooling function activated.

[0123] Although the airflow of fan 32 was varied within the range of 14.4 L / min to 44.4 L / min, the temperature of the gas ejected from gas pipe 31 into heat treatment space 11 was above 770°C and below 772°C. The temperature of the inner wall of the main body 10 near the first suction nozzle 16 and the second suction nozzle 17 facing heat treatment space 11 was measured to be 783°C. Therefore, the temperature of the gas ejected from gas pipe 31 into heat treatment space 11 was close to the furnace temperature.

[0124] Furthermore, the greater the airflow of fan 32, the higher the temperature of the gas drawn from heat treatment space 11 through heat storage body 40 and the temperature of the gas flowing into fan 32. Additionally, although the temperature varies depending on the airflow of fan 32, the gas passing through heat storage body 40 experiences a temperature drop of approximately 8°C to 16°C before flowing into fan 32. In this experimental example, when the airflow of fan 32 was set to 44.4 L / min, the temperature of the gas flowing into fan 32 reached a maximum of 59°C, but this temperature is below the heat resistance temperature of fan 32.

[0125] Furthermore, even when the furnace temperature is set to a temperature higher than 800°C, by providing a cooler 33 with high heat exchange capacity, such as the heating furnace 100 in this embodiment, the temperature of the gas flowing into the fan 32 can be reduced to below 60°C.

[0126] Here, when the object to be processed 1 is an unfired ceramic body used to manufacture ceramic electronic components such as multilayer ceramic capacitors, the binder is removed and various reactions are performed by heat treatment. The binder is, for example, carbon. For example, the binder in the ceramic body undergoes thermal decomposition at a temperature of around 150°C, and is eventually almost completely removed during the period up to a temperature exceeding 1000°C. However, it is preferable to remove the remaining components rapidly even at a temperature of approximately 600°C or higher. For example, it is known that if the temperature inside the furnace reaches its maximum temperature while the binder is not completely removed, structural defects and quality degradation will occur in the manufactured ceramic electronic components. Therefore, rapid removal of the binder is important.

[0127] Generally, gas flow is effective for removing adhesives, therefore it is preferable to supply gas at a sufficiently high flow rate to the vicinity of the workpiece 1. By supplying gas at a sufficiently high flow rate to the vicinity of the workpiece 1, the concentration of the gas containing the loose particles from the interior of the workpiece 1 decreases, thereby promoting the removal of the loose particles from the interior of the workpiece 1. Conversely, at low gas flow rates, it becomes difficult to promote the removal of the loose particles from the interior of the workpiece 1.

[0128] In the heating furnace 100 of this embodiment, the suction ejection section 30 repeatedly draws gas from the heat treatment space 11 to the gas pipe 31 and ejects the gas drawn into the gas pipe 31 back into the heat treatment space 11. This eliminates the need to reintroduce gas from outside the furnace, allowing for the supply of gas at a sufficiently high flow rate to the vicinity of the workpiece 1. Since the gas ejected from the gas pipe 31 into the heat treatment space 11 has the same composition as the gas inside the heat treatment space 11, reaction deviations between the workpiece 1 at the location reached by the gas ejected from the gas pipe 31 and those at locations not reached by the gas ejected from the gas pipe 31 can be suppressed.

[0129] Furthermore, in the heating furnace 100 of this embodiment, a heat storage body 40 is disposed in the part of the gas pipeline 31 located inside the main body 10. Therefore, compared with the structure in which the heat storage body 40 is disposed outside the main body 10, the temperature of the gas ejected from the gas pipeline 31 into the heat treatment space 11 can be close to the temperature of the gas inside the heat treatment space 11.

[0130] Regarding the removal of the aforementioned adhesive, more specific examples will be given. Here, an example will be given of carbon present in the treated material 1 as an adhesive, which is removed by burning the carbon. The removal of carbon can be carried out by the reaction formula (1) below.

[0131] C + 2H₂O → CO₂ + 2H₂ (1)

[0132] The reaction based on equation (1) is called an aqueous gas reaction, which is generally carried out to remove carbon at a high temperature of about 600°C or above. In this reaction, as shown in equation (1), in addition to CO2 produced by the combustion of carbon, H2 gas is also produced. According to the law of mass action, if the concentration of CO2 or H2 in or near the treated object 1 increases, it will act in the direction of inhibiting the reaction shown in equation (1).

[0133] Therefore, in the process of carbon combustion, it is necessary to maintain a low concentration of CO2 and H2 in or near the processed object 1. For this purpose, it is necessary to continuously supply fresh gas, i.e., a gas with a low concentration of CO2 and H2 as the generated gas based on equation (1), toward the processed object 1. However, under conditions of low gas flow rate and low gas velocity around the processed object 1, the generated gas remains in or near the processed object 1, and the reaction shown in equation (1) becomes difficult to advance.

[0134] In contrast, when using the heating furnace 100 in this embodiment, since the suction ejection section 30 repeatedly draws gas from the heat treatment space 11 of the main body 10 into the gas pipe 31 and ejects gas with the same composition and temperature as the gas in the heat treatment space 11 toward the workpiece 1, a gas flow substantially tens of times greater can be formed near the workpiece 1 compared to a structure without the suction ejection section 30. Therefore, the flow rate of gas near the workpiece 1 increases, and the flow velocity of gas near the workpiece 1 increases, thus suppressing the retention of CO2 and H2 gases generated by the reaction of formula (1) in or near the workpiece 1, thereby reducing the concentration of CO2 and H2 gases in or near the workpiece 1. Therefore, the reaction shown in formula (1) becomes easier to advance, and the removal of carbon from the workpiece 1 proceeds rapidly, suppressing deviations in the amount of residual carbon in each workpiece 1. Thus, a high-quality product with low residual carbon can be obtained.

[0135] <Second Implementation Method>

[0136] Figure 5 This is a schematic cross-sectional view showing the structure of the heating furnace 100A in the second embodiment. The heating furnace 100A in the second embodiment differs from the heating furnace 100 in the first embodiment in the structure of the suction ejection section 30.

[0137] In the heating furnace 100A of this embodiment, the suction ejection section 30, compared to the structure of the suction ejection section 30 in the first embodiment, also includes a third fan 32c and a fourth fan 32d. The third fan 32c and the fourth fan 32d, like the first fan 32a and the second fan 32b, can be of any configuration as long as they can deliver air.

[0138] The third fan 32c is a fan disposed in the first extension 31a of the gas conduit 31, used to make the gas flow in the opposite direction to the gas flow generated by the drive of the first fan 32a. As described above, the first fan 32a is configured such that gas flows from the first extension 31a to the third extension 31c when driven, therefore the third fan 32c is configured such that gas flows from the third extension 31c to the first extension 31a when driven.

[0139] In this embodiment, the first fan 32a and the third fan 32c are configured such that gas generated by driving one fan flows toward the other fan. As described above, the first fan 32a is configured such that gas flows from the first extension 31a to the third extension 31c during driving; therefore, the third fan 32c is positioned in the first extension 31a of the gas duct 31 on the opposite side from the first fan 32a and the first cooler 33a. With this configuration, gas generated by driving the first fan 32a flows toward the third fan 32c, and gas generated by driving the third fan 32c flows toward the first fan 32a.

[0140] The fourth fan 32d is a fan disposed in the second extension 31b of the gas conduit 31, used to make the gas flow in the opposite direction to the gas flow generated by the drive of the second fan 32b. As described above, the second fan 32b is configured such that gas flows from the second extension 31b to the third extension 31c when driven, therefore the fourth fan 32d is configured such that gas flows from the third extension 31c to the second extension 31b when driven.

[0141] In this embodiment, the second fan 32b and the fourth fan 32d are configured such that gas generated by driving one fan flows toward the other. As described above, the second fan 32b is configured such that gas flows from the second extension 31b to the third extension 31c during driving; therefore, the fourth fan 32d is positioned in the second extension 31b of the gas duct 31 on the opposite side from the second fan 32b and the second cooler 33b. With this configuration, gas generated by driving the second fan 32b flows toward the fourth fan 32d, and gas generated by driving the fourth fan 32d flows toward the second fan 32b.

[0142] In this way, by providing two fans with opposite gas flow directions at the first extension 31a and the second extension 31b of the gas pipeline 31, the load of pressure loss generated by the fan drive can be distributed between the two fans. As a result, the fan 32 provided in the gas pipeline 31 can be miniaturized.

[0143] Here, the suction and ejection of gas via gas pipe 31 in the heating furnace 100A of the second embodiment will be described. When gas is drawn from the first suction outlet 16 into the gas pipe 31 from the heat treatment space 11 of the main body 10, as shown in FIG6(a), the first fan 32a and the fourth fan 32d are driven, while the second fan 32b and the third fan 32c are in a non-driven state. At this time, the cooling function of the first cooler 33a is set to on, and the cooling function of the second cooler 33b is set to off.

[0144] Conversely, when gas is drawn from the second suction nozzle 17 into the gas pipe 31 from the heat treatment space 11 of the main body 10, as shown in FIG6(b), the second fan 32b and the third fan 32c are driven, while the first fan 32a and the fourth fan 32d are in a non-driven state. At this time, the cooling function of the first cooler 33a is set to off, and the cooling function of the second cooler 33b is set to on.

[0145] Here, the configurations of the first fan 32a and the third fan 32c can also be reversed. However, the inventors have found through experiments that, with such a configuration, the pressure loss generated by the non-driven fan 32 increases. Therefore, it is preferable to configure it as in this embodiment, such that the gas generated by driving one of the fans, the first fan 32a and the third fan 32c, is directed towards the other fan.

[0146] Similarly, the configuration of the second fan 32b and the fourth fan 32d can be reversed, but in order to reduce pressure loss, it is preferable to configure it as in this embodiment so that the gas generated by the drive of one of the fans, the second fan 32b and the fourth fan 32d, is directed toward the other fan.

[0147] The heating furnace 100A in this embodiment, like the heating furnace 100 in the first embodiment, can shorten the path length of the gas pipeline 31, making the overall structure of the heating furnace 100A more compact. Furthermore, the same applies to the heating furnaces in all the embodiments described below.

[0148] <Third Implementation Method>

[0149] In the heating furnace 100 of the first embodiment and the heating furnace 100A of the second embodiment, the gas pipeline 31 includes a first extension 31a, a second extension 31b, and a third extension 31c, which are portions extending in the horizontal direction.

[0150] In contrast, in the heating furnace 100B of the third embodiment, the gas pipeline 31 includes a portion extending in the horizontal direction and a portion extending in the vertical direction.

[0151] Furthermore, in the heating furnace 100B of this embodiment, similarly to the heating furnace 100A of the second embodiment, the suction ejection section 30 not only includes the first fan 32a and the second fan 32b, but also includes the third fan 32c and the fourth fan 32d. However, it is also possible to omit the structure of the third fan 32c and the fourth fan 32d.

[0152] Figure 7 This is a schematic cross-sectional view illustrating the structure of the heating furnace 100B in the third embodiment. Figure 1 Similarly,Figure 7 A cross-section of the heating furnace 100B is shown when it is cut with a plane orthogonal to the conveying direction of the workpiece 1. Figure 8 This schematically shows the view from the direction of arrow Y1. Figure 7 The diagram shows the structure of the heating furnace 100B.

[0153] In this embodiment, the gas pipeline 31 has the following characteristics: Figure 5 The gas conduit 31 shown is bent upwards at the midpoint of the first extension 31a and the third extension 31c. That is, the gas conduit 31 in this embodiment also includes the first extension 31a, the second extension 31b, and the third extension 31c, but the shapes of the first extension 31a and the second extension 31b are different from those of the gas conduit 31c. Figure 5 The gas pipeline 31 shown is different.

[0154] The first extension 31a in this embodiment has: a first horizontal portion 31a1, which extends horizontally from the first suction nozzle 16 toward the outside of the main body portion 10; and a first vertical portion 31a2, which is connected to the first horizontal portion 31a1 and extends vertically.

[0155] The second extension 31b in this embodiment has: a second horizontal portion 31b1, which extends horizontally from the second suction nozzle 17 toward the outside of the main body portion 10; and a second vertical portion 31b2, which is connected to the second horizontal portion 31b1 and extends vertically.

[0156] The third extension 31c extends in the horizontal direction and connects the first vertical portion 31a2 of the first extension 31a and the second vertical portion 31b2 of the second extension 31b.

[0157] The first heat storage body 40a is disposed in the first extension 31a of the gas pipeline 31 as a first horizontal section 31a1 extending in the horizontal direction. The second heat storage body 40b is disposed in the second extension 31b of the gas pipeline 31 as a second horizontal section 31b1 extending in the horizontal direction. Even in this embodiment, the first heat storage body 40a and the second heat storage body 40b are disposed inside the gas pipeline 31 and penetrate the area of ​​the main body 10.

[0158] like Figure 8 As shown, the first cooler 33a, the first fan 32a, and the third fan 32c are arranged in the first extension 31a of the gas pipeline 31 as a first vertical portion 31a2 extending in the vertical direction. The relative arrangement of the first cooler 33a, the first fan 32a, and the third fan 32c is the same as that of the heating furnace 100A in the second embodiment.

[0159] The gas flowing through the gas pipe 31 is cooled by the first cooler 33a, which is activated by the cooling function. When the temperature of the cooled gas is below its dew point, water vapor contained in the gas condenses and adheres to the surface. In the furnace 100B of this embodiment, since the first cooler 33a is located at the first vertical portion 31a2 of the gas pipe 31, the condensate adhering to the surface of the first cooler 33a can be allowed to fall off. Therefore, the state of condensate adhering to the surface of the first cooler 33a can be prevented from changing.

[0160] like Figure 8 As shown, the second cooler 33b, the second fan 32b, and the fourth fan 32d are arranged in the second extension 31b of the gas pipe 31 as a second vertical portion 31b2 extending in the vertical direction. The relative arrangement of the second cooler 33b, the second fan 32b, and the fourth fan 32d is the same as that of the heating furnace 100A in the second embodiment.

[0161] The gas flowing through the gas pipe 31 is cooled by the second cooler 33b, which is activated by the cooling function. When the temperature of the cooled gas is below its dew point, water vapor contained in the gas condenses and adheres to the surface. In the furnace 100B of this embodiment, since the second cooler 33b is located at the second vertical portion 31b2 of the gas pipe 31, the condensate adhering to the surface of the second cooler 33b can be allowed to fall off. Therefore, the state of condensate adhering to the surface of the second cooler 33b can be prevented from changing.

[0162] The heating furnace 100B in this embodiment also includes a vaporizer 34, which is disposed inside the gas pipeline 31, vertically below the cooler 33, for vaporizing water. The vaporizer 34 may be, for example, a radiator containing metals such as aluminum, iron, or copper, or ceramic, and has heat dissipation fins. The surface of the radiator may also be porous. However, the vaporizer 34 is not limited to a radiator as long as it can vaporize water. In this embodiment, the vaporizer 34 includes a first vaporizer 34a and a second vaporizer 34b.

[0163] The first vaporizer 34a is disposed inside the gas pipeline 31, vertically below the first cooler 33a, and at the junction of the first horizontal part 31a1 and the first vertical part 31a2. The first vaporizer 34a is configured to vaporize the condensate that forms and falls on the surface of the first cooler 33a.

[0164] The second vaporizer 34b is disposed inside the gas pipeline 31, vertically below the second cooler 33b, and at the junction of the second horizontal portion 31b1 and the second vertical portion 31b2. The second vaporizer 34b is configured to vaporize the condensate that forms and falls on the surface of the second cooler 33b.

[0165] As an example, when the dew point of the gas drawn from the heat treatment space 11 to the gas line 31 at a rate of 30 L / min is 60°C, the amount of condensation when cooled to 50°C by the cooler 33 is equivalent to 2.3 ccm. When the gas is drawn in and ejected in a cycle of 10 seconds, about 0.4 cc of condensation is generated per cycle and adheres to the surface of the cooler 33.

[0166] If the suction and ejection of gas are switched at given intervals by the control of the fan 32, the condensed water carried by the switched gas flow moves to the higher temperature side in the cooler 33 or falls downwards. The condensed water falling downwards comes into contact with the vaporizer 34 and vaporizes, flowing back into the heat treatment space 11 of the main body 10 as water vapor.

[0167] In this way, according to the heating furnace 100B in the third embodiment, the gas pipeline 31 includes a portion extending in the horizontal direction and a portion extending in the vertical direction, and the cooler 33 is arranged in the portion extending in the vertical direction, so that the condensate generated on the surface of the cooler 33 can fall off. As a result, it is possible to prevent the state of condensate adhering to the surface of the cooler 33 from remaining unchanged.

[0168] Furthermore, the heating furnace 100B in the third embodiment includes a vaporizer 34 disposed vertically below the cooler 33 inside the gas pipe 31 for vaporizing water, thus enabling the condensate falling from the surface of the cooler 33 to be rapidly vaporized. As a result, the condensate is not retained inside the gas pipe 31 and can be quickly returned to the heat treatment space 11, allowing a gas with the same composition as the gas drawn from the heat treatment space 11 into the gas pipe 31 to be ejected from the gas pipe 31 into the heat treatment space 11.

[0169] Furthermore, the vaporizer 34 can be omitted as long as the condensate that is generated and falls on the surface of the cooler 33 is vaporized inside the gas pipe 31.

[0170] <Fourth Implementation>

[0171] Figure 9 This is a cross-sectional view schematically showing the structure of the heating furnace 100C in the fourth embodiment. Figure 9 The cut-off position of the sectional view shown is... Figure 2 The cut-off points in the cross-sectional views shown are the same. Furthermore, in the heating furnace 100C of this embodiment, similar to the heating furnace 100A of the second embodiment, the suction ejection section 30 includes not only the first fan 32a and the second fan 32b, but also the third fan 32c and the fourth fan 32d. However, it is also possible to omit the structure of the third fan 32c and the fourth fan 32d.

[0172] The heating furnace 100C in the fourth embodiment differs from the heating furnace 100A in the presence of a heat storage body 40. Specifically, a portion of the heat storage body 40 in the fourth embodiment is exposed within the heat treatment space 11 of the main body 10. Similar to the heating furnace 100A in the second embodiment, the heat storage body 40 includes a first heat storage body 40a and a second heat storage body 40b, with portions of both the first heat storage body 40a and the second heat storage body 40b exposed within the heat treatment space 11.

[0173] The length of the heat storage body 40 protruding into the heat treatment space 11 of the main body 10 can be set appropriately. As an example, when the length of the heat storage body 40 is 221 mm, the length of the part exposed in the heat treatment space 11 is 20 mm.

[0174] Since a portion of the first heat storage body 40a is exposed within the heat treatment space 11, the exposed portion of the first heat storage body 40a reaches a higher temperature than the unexposed portion. Therefore, the gas ejected through the first heat storage body 40a and into the heat treatment space 11 is ejected at a higher temperature due to heat exchange with the first heat storage body 40a. Similarly, since a portion of the second heat storage body 40b is exposed within the heat treatment space 11, the gas ejected through the second heat storage body 40b and into the heat treatment space 11 is ejected at a higher temperature due to heat exchange with the second heat storage body 40b. This allows the temperature of the gas ejected into the heat treatment space 11 to be further close to the temperature of the gas inside the heat treatment space 11, further suppressing the reaction deviation between the processed object 1 and the gas.

[0175] <Fifth Implementation>

[0176] In the heating furnace 100 of the first embodiment, gas is ejected horizontally from the first suction nozzle 16 and the second suction nozzle 17 of the gas pipe 31. Therefore, the first suction nozzle 16 and the second suction nozzle 17 are preferably positioned at a height as close as possible to the drive roller 13 of the mounting plate 2, so that gas is ejected toward the plurality of processed objects 1 on the plate 2.

[0177] However, although in Figure 1 The details are omitted, but a drive unit such as a motor for driving the drive roller 13 is provided on the first side wall 10a of the main body 10 connected to the gas pipeline 31. Therefore, if the first suction nozzle 16 and the second suction nozzle 17 are positioned at a height as close as possible to the drive roller 13, the drive unit of the drive roller 13 and the gas pipeline 31 may interfere with each other, requiring careful design considerations.

[0178] Therefore, in the heating furnace 100D of the fifth embodiment, the first suction nozzle 16 and the second suction nozzle 17 are located at a position away from the drive section of the drive roller 13.

[0179] Figure 10 This is a schematic cross-sectional view illustrating the structure of the heating furnace 100D in the fifth embodiment. Figure 1 Similarly, Figure 10 A cross-section of the heating furnace 100D is shown when it is cut with a plane orthogonal to the conveying direction of the workpiece 1.

[0180] Compared to the heating furnace 100 in the first embodiment, the first suction nozzle 16 in this embodiment is positioned higher than the drive roller 13, that is, it is positioned away from the drive roller 13 in the height direction orthogonal to the conveying surface of the drive roller 13. The same applies to the second suction nozzle 17, although the figure is omitted. This configuration helps to suppress interference between the drive section of the drive roller 13 and the gas pipeline 31.

[0181] like Figure 10 As shown, in the heating furnace 100D of this embodiment, similarly to the heating furnace 100C of the fourth embodiment, a portion of the first heat storage body 40a is exposed within the heat treatment space 11. Similarly, a portion of the second heat storage body 40b is exposed within the heat treatment space 11. However, it is also possible to configure a structure in which a portion of the first heat storage body 40a and a portion of the second heat storage body 40b are not exposed within the heat treatment space 11.

[0182] In this embodiment, the gas conduit 31 is configured such that the dot product of a unit normal vector extending toward the side on which the workpiece 1 is placed relative to the placement surface within the heat treatment space 11 and a unit vector along the direction of travel of the gas ejected from the gas conduit 31 into the heat treatment space 11 is negative. For this purpose, using... Figure 11 Let me explain.

[0183] Furthermore, since gas is ejected from the gas pipe 31 toward the front end along the direction of the gas pipe 31, the unit vector along the direction of travel of the gas ejected from the gas pipe 31 toward the heat treatment space 11 means the unit vector along the direction of travel of the gas extending toward the front end along the direction of the gas pipe 31.

[0184] Figure 11This diagram illustrates the relationship between the unit vector v, which represents the direction of travel of the gas ejected from the first extension 31a of the gas conduit 31 via the first suction nozzle 16 into the heat treatment space 11, and the unit normal vector n, which extends towards the side of the plate 2 on which the workpiece 1 is placed, relative to the placement surface 2a of the plate 2 on which the workpiece 1 is placed. The dot product (v·n) of the unit vector v and the unit normal vector n is negative. That is, the orientation of the first extension 31a of the gas conduit 31 is adjusted so that gas is ejected obliquely downward from the gas conduit 31 via the first suction nozzle 16.

[0185] Although the diagram is omitted, the dot product (v·n) of the unit vector v along the direction of travel of the gas ejected from the second extension 31b of the gas pipe 31 through the second suction nozzle 17 into the heat treatment space 11 and the unit normal vector n extending toward the side of the plate 2 on which the workpiece 1 is placed relative to the plate 2 on which the workpiece 1 is placed is also negative. That is, the orientation of the second extension 31b of the gas pipe 31 is adjusted so that gas is ejected obliquely downward from the gas pipe 31 through the second suction nozzle 17.

[0186] According to the heating furnace 100D in the fifth embodiment, interference between the drive section of the drive roller 13 and the gas pipeline 31 can be suppressed. Furthermore, since gas is blown from an oblique upward direction onto the multiple workpieces 1 on the plate 2 within the heat treatment space 11, gas can be blown onto more workpieces 1. This allows for a more efficient reaction on more workpieces 1 and further suppresses deviations in the reaction of each workpiece 1.

[0187] <Sixth Implementation>

[0188] Figure 12 This is a schematic cross-sectional view illustrating the structure of the heating furnace 100E in the sixth embodiment. Furthermore, Figure 13 This is an enlarged cross-sectional view of the area near the first suction nozzle 16 in the gas pipeline 31.

[0189] like Figure 13 As shown, the cross-sectional area of ​​the first extension 31a of the gas pipe 31 decreases toward the first suction nozzle 16. More specifically, among the cross-sectional areas when the first extension 31a of the gas pipe 31 is cut off with a plane orthogonal to the extension direction, the cross-sectional area Si of the front end on the heat treatment space 11 side is smaller than the average cross-sectional area Sm of the region where the first heat storage body 40a is disposed.

[0190] Although the diagram is omitted, the same applies to the side of the second suction outlet 17 of the gas pipe 31. That is, the cross-sectional area of ​​the second extension 31b of the gas pipe 31 decreases towards the front end of the heat treatment space 11. More specifically, among the cross-sectional areas when the second extension 31b of the gas pipe 31 is cut with a plane orthogonal to the extension direction, the cross-sectional area Si of the front end of the heat treatment space 11 side is smaller than the average cross-sectional area Sm of the region where the second heat storage body 40b is disposed.

[0191] In this way, the cross-sectional area of ​​the gas pipe 31 decreases towards the front end facing the heat treatment space 11, thus increasing the flow rate when gas is ejected from the gas pipe 31 into the heat treatment space 11. This allows for the formation of a faster gas flow near the workpiece 1, further advancing the heat treatment reaction and suppressing reaction deviations in each workpiece 1. Consequently, it further suppresses quality deviations in the product obtained through heat treatment of the workpiece 1.

[0192] Furthermore, due to the increased flow rate of the gas ejected into the heat treatment space 11, an entrainment phenomenon occurs within the heat treatment space 11, resulting in an increase in the high-temperature gas entrained in the ejected flow. Consequently, the temperature of the gas ejected into the heat treatment space 11 and flowing near the workpiece 1 becomes closer to the temperature of the gas within the heat treatment space 11, thus further suppressing reaction deviations in each workpiece 1.

[0193] <Seventh Implementation>

[0194] In the heating furnace 100 of the first embodiment to the heating furnace 100E of the sixth embodiment, the main body 10 is generally cuboid and has openings at both ends in the conveying direction of the processed object 1. In contrast, in the heating furnace 100F of the seventh embodiment, the main body 10 has a generally spherical shape.

[0195] Furthermore, even in the heating furnace 100F of this embodiment, similar to the heating furnace 100A of the second embodiment, the suction ejection section 30 not only includes the first fan 32a and the second fan 32b, but also the third fan 32c and the fourth fan 32d. However, it is also possible to omit the structure of the third fan 32c and the fourth fan 32d.

[0196] Figure 14 This is a schematic cross-sectional view showing the structure of the heating furnace 100F in the seventh embodiment. Figure 14 The cut-off position of the sectional view shown is... Figure 2 The cut-off points in the sectional views shown are the same.

[0197] Even in the heating furnace 100F of this embodiment, the gas pipe 31 is configured such that, during gas attraction and ejection, the dot product of the unit vector along the travel direction of the gas ejected from the gas pipe 31 to the heat treatment space 11 and the unit vector along the travel direction of the gas attracted from the heat treatment space 11 to the gas pipe 31 is less than 0. To shorten the path length of the gas pipe 31, it is preferable to configure the gas pipe 31 such that the positions of the first attraction nozzle 16 and the second attraction nozzle 17 are close together. Furthermore, in Figure 14 In the diagram, arrows indicate the gas flow as gas is drawn from the heat treatment space 11 into the gas pipeline 31 via the first suction nozzle 16 and ejected into the heat treatment space 11 via the second suction nozzle 17.

[0198] Even in the heating furnace 100F of the seventh embodiment, the gas pipe 31 is configured such that, during gas attraction and ejection, the dot product of the unit vector along the travel direction of the gas ejected from the gas pipe 31 to the heat treatment space 11 and the unit vector along the travel direction of the gas attracted from the heat treatment space 11 to the gas pipe 31 is less than 0. Therefore, the path length of the gas pipe 31 can be shortened, and the structure of the heating furnace 100F can be made smaller. Furthermore, by shortening the path length of the gas pipe 31, heat dissipation to the outside of the flow path when the gas flows through the gas pipe 31 can be suppressed, thereby improving thermal efficiency.

[0199] <Eighth Implementation>

[0200] The heating furnace 100 in the first embodiment to the heating furnace 100F in the seventh embodiment each have one suction ejection section 30. In contrast, the heating furnace 100G in the eighth embodiment has multiple suction ejection sections 30.

[0201] Figure 15 This is a cross-sectional view schematically showing the structure of the heating furnace 100G in the eighth embodiment. Figure 15 The cut-off position of the sectional view shown is... Figure 2 The cut-off points in the sectional views shown are the same.

[0202] exist Figure 15 In the example shown, four suction ejection sections 30 are provided. Specifically, two suction ejection sections 30 are provided on the first sidewall 10a of the main body 10, and two suction ejection sections 30 are provided on the second sidewall 1ob opposite to the first sidewall 10a. However, the number of suction ejection sections 30 is not limited to four, and all suction ejection sections 30 may be provided on one sidewall.

[0203] As in this invention, by configuring the gas conduit 31 such that the dot product of the unit vector along the direction of travel of the gas ejected from the gas conduit 31 into the heat treatment space 11 and the unit vector along the direction of travel of the gas attracted from the heat treatment space 11 into the gas conduit 31 is less than 0, the path length of the gas conduit 31 can be shortened, thus allowing for the provision of multiple suction ejection sections 30. This, in turn, further suppresses reaction deviations in the processed material 1.

[0204] The suction ejection portion 30 disposed on the first sidewall 10a of the main body 10 and the suction ejection portion 30 disposed on the second sidewall 10b are preferably disposed in opposite positions. More specifically, the first suction ejection outlet 16 of the gas pipe 31 connected to the second sidewall 10b of the main body 10 is preferably located opposite to the first suction ejection outlet 16 of the gas pipe 31 connected to the first sidewall 10a, and the second suction ejection outlet 17 of the gas pipe 31 connected to the second sidewall 10b is located opposite to the second suction ejection outlet 17 of the gas pipe 31 connected to the first sidewall 10a.

[0205] Furthermore, it is preferable to control the suction ejection section 30 to be positioned in the direction opposite to the first sidewall 10a and the second sidewall 10b, such as... Figure 15 As shown, the gas flows in the same direction. Figure 15 In the example shown, arrows indicate the gas flow when gas is drawn from the first suction nozzle 16 of the gas pipe 31 connected to the first sidewall 10a and ejected from the second suction nozzle 17. Similarly, arrows indicate the gas flow when gas is ejected from the first suction nozzle 16 of the gas pipe 31 connected to the second sidewall 10b and drawn from the second suction nozzle 17. By controlling both the gas suction and ejection, gas can be suctioned simultaneously at the same position as the gas ejected into the heat treatment space 11 in its straight-line direction of travel, thus ensuring greater straight-line propagation of the gas ejected from the gas pipe 31 into the heat treatment space 11. Consequently, gas can flow over and around the surface of more of the workpieces 1, further suppressing reaction deviations in the heat treatment of each workpiece 1.

[0206] This invention is not limited to the embodiments described above, and various applications and modifications can be applied within the scope of this invention. For example, the characteristic structures of the heating furnace in each embodiment can be appropriately combined.

[0207] The shape of the main body 10 is not limited to the shape described in the above embodiments. Even if the shape of the main body 10 is other than the above-described approximately cuboid or approximately spherical shape, it is sufficient that the dot product of the unit vector of the gas pipe 31 along the direction of travel of the gas ejected from the gas pipe 31 to the heat treatment space 11 and the unit vector along the direction of travel of the gas drawn from the heat treatment space 11 to the gas pipe 31 is 0 or less when the gas is drawn in and ejected through the gas pipe 31.

[0208] In the embodiments described above, the suction and ejection section 30 is equipped with a fan 32, and the suction of gas from the heat treatment space 11 to the gas pipe 31 and the ejection of gas from the gas pipe 31 to the heat treatment space 11 are described by driving the fan 32. However, the power source for suction and ejection of gas is not limited to the fan 32. For example, a piston may be arranged in the gas pipe 31, and the suction and ejection of gas may be achieved by the reciprocating movement of a movable part inside the piston cylinder.

Claims

1. A heating furnace, characterized in that, have: The main body has a heat treatment space for performing heat treatment on the workpiece, and includes a heating unit disposed within the heat treatment space. A gas supply unit that supplies the gas required for heat treatment to the heat treatment space of the main body; The suction ejection section has a gas pipeline connected to the main body, and repeatedly performs the suction of gas from the heat treatment space to the gas pipeline and the ejection of the gas attracted to the gas pipeline to the heat treatment space. and A heat storage element, disposed inside the gas pipeline, is capable of heat exchange. The gas pipeline is configured such that, during the attraction and ejection of gas via the gas pipeline, the dot product of the unit vector along the travel direction of the gas ejected from the gas pipeline into the heat treatment space and the unit vector along the travel direction of the gas attracted from the heat treatment space into the gas pipeline is less than 0. The gas pipeline includes a first extension extending from a first suction nozzle at one end toward the outer side of the main body and a second extension extending from a second suction nozzle at the other end toward the outer side of the main body. The suction ejection section includes a first fan disposed in the first extension and a second fan disposed in the second extension. The heating furnace also includes a cooler disposed in the gas pipeline for cooling the gas drawn from the heat treatment space and passing through the heat storage body. The heat storage body includes a first heat storage body disposed in the first extension and a second heat storage body disposed in the second extension. The cooler includes a first cooler disposed between the first heat storage body and the first fan, and a second cooler disposed between the second heat storage body and the second fan.

2. The heating furnace according to claim 1, characterized in that, The heat storage body is disposed inside the gas pipeline, located in the part inside the main body.

3. The heating furnace according to claim 2, characterized in that, The heat storage element is disposed inside the gas pipeline and penetrates the area of ​​the main body.

4. The heating furnace according to any one of claims 1 to 3, characterized in that, A portion of the heat storage body is exposed within the heat treatment space of the main body.

5. The heating furnace according to any one of claims 1 to 3, characterized in that, The gas pipeline is configured such that the dot product of a unit normal vector extending toward the side on which the workpiece is placed and a unit vector along the direction of travel of the gas ejected from the gas pipeline into the heat treatment space is negative, relative to the placement surface on which the workpiece is placed.

6. The heating furnace according to any one of claims 1 to 3, characterized in that, Of the cross-sectional areas when the gas pipeline is cut off with a plane orthogonal to the extension direction, the cross-sectional area of ​​the front end of the heat treatment space side is smaller than the average cross-sectional area of ​​the region where the heat storage body is disposed.

7. The heating furnace according to claim 1, characterized in that, The suction ejection section further includes: a third fan disposed in the first extension for causing the gas to flow in the opposite direction to the gas flow generated by the drive of the first fan; and a fourth fan disposed in the second extension for causing the gas to flow in the opposite direction to the gas flow generated by the drive of the second fan.

8. The heating furnace according to claim 7, characterized in that, The first fan and the third fan are configured such that the gas generated by the drive of one fan is directed toward the other fan. The second and fourth fans are configured such that the gas generated by the drive of one fan is directed toward the other fan.

9. The heating furnace according to claim 1, characterized in that, The cooler is a heat exchanger that alternately stacks a gas flow path for flowing gas and a refrigerant flow path for flowing refrigerant.

10. The heating furnace according to claim 1 or 9, characterized in that, The first cooler and the second cooler are configured such that the cooling function of the cooler disposed in the extension of the gas pipeline that serves as the gas suction flow path is turned on, and the cooling function of the cooler disposed in the extension of the gas ejection flow path is turned off.

11. The heating furnace according to claim 1 or 9, characterized in that, The gas pipeline includes a portion extending in the horizontal direction and a portion extending in the vertical direction. The heat storage body is disposed in the portion of the gas pipeline extending in the horizontal direction, and the cooler is disposed in the portion extending in the vertical direction.

12. The heating furnace according to claim 11, characterized in that, The heating furnace also includes a vaporizer disposed inside the gas pipeline, vertically below the cooler, for vaporizing water.

13. The heating furnace according to any one of claims 1 to 3, characterized in that, The suction ejection section is provided in multiple ways.

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