Heating furnace

Abstract

To provide a heating furnace having a long gas line route, and a large total size of the furnace.SOLUTION: A heating furnace 100 has a body part 10 having a heating space 11 for heat-treating a heating object, a gas supply part 20 supplying gas necessary for heat-treatment to the heating space 11 of the body part 10, a suction / ejection part 30 having a gas line 31 connected to the body part 10 and sucking gas from the heating space 11 to the gas line 31 and ejecting the sucked gas to the heating space 11 repeatedly, and a heat storage body 40 arranged inside the gas line 31 and allowing heat exchange. The gas line 31 is arranged in such a way that, in gas sucking and ejecting via the gas line 31, an inner product of unit vector along an advancing direction of the gas ejected to the heating space 11 from the gas line 31 and the unit vector along the advancing direction of the gas sucked to the gas line 31 from the heating space 11 is 0 or less.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a heating furnace. [Background technology]

[0002] 2. Description of the Related Art There is known a heating furnace in which a gas is supplied into the furnace to perform heat treatment on an object to be treated.

[0003] As one such heating furnace, Patent Document 1 discloses a heating furnace in which gas in the furnace is introduced into an external circulation path by a circulation fan, and the gas introduced into the external circulation path is returned to the furnace. In this heating furnace, a heat storage body is provided at a position outside the furnace in the external circulation path. The gas introduced from inside the furnace into the external circulation path is heat exchanged in the heat storage body to be cooled, and the gas returned to the furnace is heat exchanged in the heat storage body to be heated to a high temperature before being ejected into the furnace. With such a configuration, the heating furnace described in Patent Document 1 is said to be able to supply a strong circulation flow at a high temperature into the furnace. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-178112 Summary of the Invention [Problem to be solved by the invention]

[0005] In the heating furnace described in Patent Document 1, one end of the external circulation path is connected to one of a pair of opposing side walls, and the other end of the external circulation path is connected to the other side wall, which increases the path length of the external circulation path and increases the overall size of the heating furnace.

[0006] The present invention is devised to solve the above-mentioned problems, and has an object to provide a heating furnace that can reduce the overall size by shortening the path length of the gas line connected to the main body of the heating furnace. [Means for solving the problem]

[0007] The heating furnace of the present invention is a main body having a heat treatment space for performing heat treatment on an object to be treated and including a heating unit disposed within the heat treatment space; a gas supply unit that supplies a gas necessary for performing heat treatment to the heat treatment space of the main body; a suction / blowout unit having a gas line connected to the main body, the suction unit repeatedly sucking gas from the heat treatment space into the gas line and blowing the gas sucked into the gas line into the heat treatment space; A heat storage body capable of exchanging heat is disposed inside the gas line; Equipped with The gas line is arranged so that, when gas is sucked in and ejected through the gas line, the dot product of a unit vector along the direction of travel of the gas ejected from the gas line to the heat treatment space and a unit vector along the direction of travel of the gas sucked from the heat treatment space to the gas line is less than or equal to 0. Effect of the Invention

[0008] In the heating furnace of the present invention, the gas lines are arranged so that the inner product of a unit vector along the direction of travel of the gas ejected from the gas line to the heat treatment space and a unit vector along the direction of travel of the gas sucked from the heat treatment space to the gas line is less than or equal to 0. By arranging in this way, the path length of the gas lines can be shortened, and the overall size of the heating furnace can be reduced. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a cross-sectional view illustrating a schematic configuration of a heating furnace according to the first embodiment. [Diagram 2] 2 is a cross-sectional view showing a schematic configuration of the heating furnace shown in FIG. 1 taken along line II-II. [Diagram 3] FIG. 1 is a perspective view showing a schematic configuration of a cooler using a compact heat exchanger. [Figure 4]1(a) is a diagram for explaining the operation of a heating furnace in the first embodiment when gas is sucked in through a first suction nozzle of a gas line and ejected from a second suction nozzle, and FIG. 1(b) is a diagram for explaining the operation of a heating furnace in the first embodiment when gas is sucked in through a second suction nozzle of a gas line and ejected from a first suction nozzle. [Diagram 5] FIG. 11 is a cross-sectional view illustrating a schematic configuration of a heating furnace according to a second embodiment. [Figure 6] 1(a) is a diagram for explaining the operation of a heating furnace in a second embodiment, when gas is sucked in through a first suction nozzle of a gas line and ejected from a second suction nozzle, and FIG. 1(b) is a diagram for explaining the operation of a heating furnace in a second embodiment, when gas is sucked in through a second suction nozzle of a gas line and ejected from a first suction nozzle. [Figure 7] FIG. 11 is a cross-sectional view that illustrates a schematic configuration of a heating furnace according to a third embodiment. [Figure 8] 8 is a diagram showing a schematic configuration of the heating furnace shown in FIG. 7 when viewed from the direction of arrow Y1. FIG. [Figure 9] FIG. 11 is a cross-sectional view that illustrates a schematic configuration of a heating furnace according to a fourth embodiment. [Figure 10] FIG. 13 is a cross-sectional view that illustrates a schematic configuration of a heating furnace according to a fifth embodiment. [Figure 11] FIG. 13 is a diagram showing the relationship between a unit vector along the direction of travel of the gas ejected from the first extension of the gas line through the first suction outlet into the heat treatment space in a heating furnace in the fifth embodiment, and a unit normal vector extending toward the side on which the workpiece is placed, relative to the mounting surface of the plate on which the workpiece is placed. [Figure 12] FIG. 13 is a cross-sectional view that illustrates a schematic configuration of a heating furnace according to a sixth embodiment. [Figure 13] FIG. 13 is an enlarged cross-sectional view of a portion of a gas line near a first suction jet port in a heating furnace according to a sixth embodiment. [Figure 14] FIG. 13 is a cross-sectional view that illustrates a schematic configuration of a heating furnace according to a seventh embodiment. [Figure 15]FIG. 13 is a cross-sectional view that illustrates a schematic configuration of a heating furnace according to an eighth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The features of the present invention will be described in detail below with reference to embodiments of the present invention.

[0011] <First embodiment> Fig. 1 is a cross-sectional view showing a schematic configuration of a heating furnace 100 in the first embodiment. Fig. 2 is a cross-sectional view showing a schematic configuration of the heating furnace 100 shown in Fig. 1 when cut along line II-II. However, in Fig. 2, a driving roller 13 described later is omitted.

[0012] Here, the heating furnace 100 will be described as a roller hearth furnace. A roller hearth furnace is a continuous type heating furnace in which a plurality of driving rollers 13 are arranged at regular intervals along the traveling direction inside the furnace, and the workpiece 1 is transported on the driving rollers 13. Fig. 1 shows a cross section of the heating furnace 100 cut along a plane perpendicular to the transport direction of the workpiece 1. However, the heating furnace 100 is not limited to a roller hearth furnace, and may be another type of heating furnace, such as a batch type heating furnace.

[0013] The heating furnace 100 includes a main body 10, a gas supply unit 20, a suction / jet unit 30, and a heat storage body 40.

[0014] The main body 10 has a heat treatment space 11 for performing heat treatment on the workpiece 1, and includes a heating unit 12 disposed within the heat treatment space 11. There are no particular restrictions on the shape or size of the main body 10. The heating unit 12 is, for example, a heater capable of heating up to about 1300°C. In this embodiment, a driving roller 13 is disposed in the heat treatment space 11, and the heating unit 12 is disposed on the opposite side of the driving roller 13 with respect to the workpiece 1, i.e., above the workpiece 1, so that the workpiece 1 is located between the driving roller 13 and the heating unit 12. However, the location of the heating unit 12 is not limited to the opposite side of the driving roller 13 with respect to the workpiece 1.

[0015] In this embodiment, the main body 10 has four furnace walls, a first side wall 10a, a second side wall 10b, a hearth wall 10c, and a ceiling wall 10d, as shown in Fig. 1. The first side wall 10a and the second side wall 10b, and the hearth wall 10c and the ceiling wall 10d, face each other in a direction perpendicular to the transport direction of the workpiece 1. As shown in Fig. 2, both ends in the transport direction of the workpiece 1 are open and connected to a loading / unloading port through which the workpiece 1 enters and exits. The furnace walls of the main body 10, including the first side wall 10a, the second side wall 10b, the hearth wall 10c, and the ceiling wall 10d, are made of, for example, a heat insulating material.

[0016] There is no restriction on the type of workpiece 1 to be heat-treated, and it may be, for example, an unfired ceramic body for producing chip-like ceramic electronic components such as a multilayer ceramic capacitor. In this embodiment, a plate 2 on which a plurality of workpieces 1 are placed is configured to be transported on a driving roller 13. The plate 2 is made of, for example, ceramic.

[0017] The gas supply unit 20 supplies gas required for heat treatment to the heat treatment space 11 of the main body 10. The main body 10 is provided with a gas supply port 14, and the gas supply unit 20 supplies the gas required for heat treatment to the heat treatment space 11 via the gas supply port 14.

[0018] The main body 10 is provided with a gas exhaust port 15 for exhausting unnecessary gas so that the pressure in the heat treatment space 11 is kept constant.

[0019] The suction and jetting part 30 has a gas line 31 connected to the main body part 10, and repeatedly sucks gas from the heat treatment space 11 into the gas line 31 and jets the gas sucked into the gas line 31 into the heat treatment space 11. In this embodiment, the gas sucked into the gas line 31 by the suction and jetting part 30 and jetted into the heat treatment space 11 has the same composition as the gas in the heat treatment space 11.

[0020] The gas line 31 is arranged so that, during the suction and ejection of the gas, the inner product of a unit vector along the traveling direction of the gas ejected from the gas line 31 to the heat treatment space 11 and a unit vector along the traveling direction of the gas sucked from the heat treatment space 11 to the gas line 31 is less than or equal to 0. To realize such a configuration, in the heating furnace 100 of this embodiment, as shown in FIG. 2, one end and the other end of the gas line 31 are both connected to the same side wall of the main body 10, more specifically, to the first side wall 10a.

[0021] However, both ends of the gas line 31 may be connected to the second side wall 10b, or may be connected to the hearth wall 10c or the ceiling wall 10d. Alternatively, one end of the gas line 31 may be connected to one of the two side walls 10a, 10b of the main body 10, and the other end may be connected to the hearth wall 10c or the ceiling wall 10d of the main body 10.

[0022] One end of the gas line 31 faces the heat treatment space 11 and constitutes a first suction jet 16. The other end of the gas line 31 faces the heat treatment space 11 and constitutes a second suction jet 17.

[0023] The gas line 31 in this embodiment has a U-shape as shown in FIG. 2. That is, the gas line 31 includes a first extension 31a extending from the first suction jet 16 located at one end toward the outside of the main body 10, a second extension 31b extending from the second suction jet 17 located at the other end toward the outside 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 linear shape. The first extension 31a and the second extension 31b extend parallel to each other in a direction perpendicular to the first side wall 10a, and the third extension 31c extends in a direction parallel to the first side wall 10a. However, the shape of the gas line 31 is not limited to a U-shape.

[0024] The first extension 31a, the second extension 31b, and the third extension 31c are all located at the same height. That is, the gas line 31 is attached to the main body 10 so that the gas flows horizontally.

[0025] In this way, the gas line 31 is arranged so that the inner product of the unit vector along the direction of travel of the gas ejected from the gas line 31 to the heat treatment space 11 and the unit vector along the direction of travel of the gas ejected from the heat treatment space 11 to the gas line 31 during the gas suction and ejection is equal to or less than 0, thereby shortening the path length of the gas line 31 and making the configuration of the heating furnace 100 compact. The shortening of the path length of the gas line 31 improves the degree of freedom in the installation location of the gas line 31 and makes it easier to install the gas line 31. Furthermore, the shortening of the path length of the gas line 31 makes it possible to suppress heat radiation to the outside of the flow path when the gas flows through the gas line 31, thereby improving thermal efficiency.

[0026] In addition, in a configuration such as the heating furnace described in Patent Document 1, in which one end of a gas line is connected to one of a pair of opposing side walls of the main body and the other end of the gas line is connected to the other, the dot product of a unit vector along the direction of travel of the gas ejected from the gas line into the heat treatment space and a unit vector along the direction of travel of the gas sucked from the heat treatment space into the gas line is positive.

[0027] The suction and jetting section 30 in this embodiment includes a first fan 32a disposed in a first extension 31a of the gas line 31 and a second fan 32b disposed in a second extension 31b of the gas line 31. The first fan 32a and the second fan 32b may have any structure as long as they are capable of blowing air. In the following description, the first fan 32a and the second fan 32b may be collectively referred to as the fan 32.

[0028] The first fan 32a is disposed so that, when driven, gas flows from the first extension 31a of the gas line 31 to the third extension 31c. That is, when the first fan 32a is driven, gas is sucked from the heat treatment space 11 to the first extension 31a of the gas line 31 through the first suction jet 16. At this time, the second fan 32b is in a non-driven state. The gas sucked from the heat treatment space 11 to the first extension 31a of the gas line 31 passes through the third extension 31c and the second extension 31b, and is ejected from the second suction jet 17 to the heat treatment space 11.

[0029] The second fan 32b is disposed so that, when driven, gas flows from the second extension 31b of the gas line 31 to the third extension 31c. That is, when the second fan 32b is driven, gas is sucked from the heat treatment space 11 to the second extension 31b of the gas line 31 through the second suction jet 17. At this time, the first fan 32a is in a non-driven state. The gas sucked from the heat treatment space 11 to the second extension 31b of the gas line 31 passes through the third extension 31c and the first extension 31a, and is ejected from the first suction jet 16 to the heat treatment space 11.

[0030] The first fan 32a may be arranged so that the gas flows from the first extension 31a of the gas line 31 to the heat treatment space 11 when the first fan 32a is driven, and the second fan 32b may be arranged so that the gas flows from the second extension 31b of the gas line 31 to the heat treatment space 11 when the first fan 32a is driven. In this case, when the first fan 32a is driven, gas is sucked from the heat treatment space 11 to the second extension 31b of the gas line 31 through the second suction nozzle 17, and the gas is ejected from the first suction nozzle 16 to the heat treatment space 11. When the second fan 32b is driven, gas is sucked from the heat treatment space 11 to the first extension 31a of the gas line 31 through the first suction nozzle 16, and the gas is ejected from the second suction nozzle 17 to the heat treatment space 11.

[0031] As described above, the gas ejected by the suction jet part 30 into the heat treatment space 11 of the main body 10 is gas sucked from the heat treatment space 11 and has the same composition as the gas in the heat treatment space 11. That is, the gas sucked from the heat treatment space 11 into the gas line 31 through the first suction jet 16 is ejected directly into the heat treatment space 11 through the second suction jet 17 without being mixed with other gases, air, etc. Similarly, the gas sucked from the heat treatment space 11 into the gas line 31 through the second suction jet 17 is ejected directly into the heat treatment space 11 through the first suction jet 16 without being mixed with other gases, air, etc. Here, the gas sucked from the heat treatment space 11 and not mixed with other gases, air, etc. is defined as the gas having the same composition as the gas in the heat treatment space 11.

[0032] The heating furnace 100 in this embodiment includes a cooler 33 disposed in the gas line 31 for cooling the gas sucked from the heat treatment space 11 and passing through a thermal storage body 40 described later. The cooler 33 includes a first cooler 33a disposed in a first extension portion 31a of the gas line 31 and a second cooler 33b disposed in a second extension portion 31b of the gas line 31. The first cooler 33a is disposed between a first thermal storage body 40a and a first fan 32a described later. The second cooler 33b is disposed between a second thermal storage body 40b and a second fan 32b described later.

[0033] The first cooler 33a cools the gas that is sucked from the heat treatment space 11 to the first extension 31a of the gas line 31 and passes through the first heat storage body 40a described later. As an example, the gas sucked from the heat treatment space 11 to the first extension 31a of the gas line 31 through the first suction nozzle 16 is cooled to about 100°C by the first heat storage body 40a. The gas cooled by the first heat storage body 40a is further cooled to 50°C or less by the first cooler 33a. This makes it possible to prevent high-temperature gas from flowing into the first fan 32a and causing thermal damage.

[0034] The second cooler 33b cools the gas that is sucked from the heat treatment space 11 to the second extension 31b of the gas line 31 and passes through the second heat storage body 40b described later. As an example, the gas sucked from the heat treatment space 11 to the second extension 31b of the gas line 31 through the second suction jet 17 is cooled to about 100°C by the second heat storage body 40b. The gas cooled by the second heat storage body 40b is further cooled to 50°C or less by the second cooler 33b. This makes it possible to prevent high-temperature gas from flowing into the second fan 32b and causing thermal damage.

[0035] 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 an equilibrium state. In other words, if the first cooler 33a and the second cooler 33b are not provided, the temperatures of the first heat storage body 40a and the second heat storage body 40b will rise in the process of repeatedly sucking gas from the heat treatment space 11 to the gas line 31 and ejecting gas from the gas line 31 to the heat treatment space 11. In that case, the temperatures 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.

[0036] However, in the heating furnace 100 of this embodiment, the first cooler 33a and the second cooler 33b are provided, so that the increase in temperature distribution of the first heat storage body 40a and the second heat storage body 40b can be suppressed, and the temperatures of the gas that has passed through the first heat storage body 40a and the gas that has passed through the second heat storage body 40b can be prevented from significantly exceeding 100°C.

[0037] 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 portion that serves as the gas suction flow path of the first extension portion 31a and the second extension portion 31b of the gas line 31 is turned on, and the cooling function of the cooler disposed in the extension portion that serves as the gas ejection flow path is turned off.

[0038] For example, a known heat exchanger can be used as the first cooler 33a and the second cooler 33b. FIG. 3 is a perspective view that shows a schematic configuration of the cooler 33 (the first cooler 33a and the second cooler 33b) that uses a compact heat exchanger, which is one of the heat exchangers. As shown in FIG. 3, the cooler 33 has a structure in which a gas flow path L1 through which high-temperature gas flows and a refrigerant flow path L2 through which a refrigerant flows are alternately stacked. The gas flow path L1 and the refrigerant flow path L2 are configured to be oriented perpendicular to each other. A plurality of fins are provided in the gas flow path L1 and the refrigerant flow path L2, and heat exchange is performed between the gas flowing through the gas flow path L1 and the refrigerant flowing through the refrigerant flow path L2.

[0039] Although FIG. 3 shows a configuration in which the gas flow passages L1 and the coolant flow passages L2 are each provided in two layers, the number of layers of the gas flow passages L1 and the coolant flow passages L2 is not limited to two.

[0040] By using a heat exchanger in which gas flow path L1 through which gas flows and refrigerant flow path L2 through which refrigerant flows are alternately stacked as the cooler 33, the required gas cooling can be achieved with a small-sized cooler, and the configuration of the heating furnace 100 can be made compact.

[0041] The cooling function of the first cooler 33a will be described. A refrigerant flows through the refrigerant flow path L2 to cool the gas flowing through the gas flow path L1. The refrigerant is, for example, cold air. For example, a cooling fan is provided upstream of the refrigerant flow path L2 to blow cold air through the refrigerant flow path L2. Gas that has passed through the first heat storage body 40a flows through the gas flow path L1.

[0042] As an example, gas at about 100°C that has passed through the first heat storage body 40a flows into the gas flow path L1 of the first cooler 33a at a volume of 30 L / min. When cold air at a volume of 30 to 120 L / min is passed as a coolant through the coolant flow path L2 of the first cooler 33a, the gas flowing through the gas flow path L1 is cooled to about 50°C. The same applies to the second cooler 33b.

[0043] The first cooler 33a and the second cooler 33b may be any cooler capable of cooling the gas, and are not limited to a heat exchanger having a structure in which the gas flow passage L1 through which the gas flows and the refrigerant flow passage L2 through which the refrigerant flows are alternately stacked. If the gas is sufficiently cooled by the heat storage body 40, the cooler 33 may be omitted.

[0044] The heat storage body 40 has a heat exchangeable structure capable of repeatedly storing and releasing heat, and is disposed inside the gas line 31. In this embodiment, the heat storage body 40 is disposed in a portion of the inside of the gas line 31 that is located inside the main body 10, specifically, in a region that penetrates the main body 10. In this embodiment, the heat storage body 40 includes a first heat storage body 40a disposed in the first extension portion 31a of the gas line 31 and a second heat storage body 40b disposed in the second extension portion 31b. The first heat storage body 40a and the second heat storage body 40b may protrude to a region outside the main body 10 within the inside of the gas line 31, but do not protrude into the heat treatment space 11 of the main body 10.

[0045] 1 and 2, the heat storage body 40 is provided in the entire region of the gas line 31 that penetrates the main body 10, but may be provided only in a part of the gas line 31. The heat storage body 40 may be provided in the gas line 31 on the outside of the main body 10.

[0046] The heat storage body 40 may have any structure capable of heat exchange, such as a cylinder having a plurality of honeycomb-shaped cell holes formed from ceramic, or a cylinder containing a plurality of ceramic spheres inside. The honeycomb-shaped cells are generally hexagonal, but may be cells of a shape other than hexagonal, such as a square or triangle. The heat storage body 40 may be made of a material other than ceramic.

[0047] Here, the gas suction and ejection operations through the gas line 31 will be described. As shown in Fig. 4(a), when the first fan 32a is driven and the second fan 32b is not driven, the gas in the heat treatment space 11 of the main body 10 is sucked from the first suction ejection port 16 to the first extension portion 31a of the gas line 31. The temperature of the gas in the heat treatment space 11 is assumed to be, for example, about 1200°C.

[0048] At this time, the cooling function of the first cooler 33a arranged in the first extension 31a which is the suction flow path of the gas is turned on, and the cooling function of the second cooler 33b arranged in the second extension 31b which is the ejection flow path of the gas is turned off. The gas sucked from the heat treatment space 11 through the first suction ejection port 16 passes through the first heat storage body 40a arranged in the first extension 31a of the gas line 31, and at this time, heat exchange is performed and the temperature drops to about 100°C. As a result, the first heat storage body 40a accumulates heat and becomes in a high temperature state.

[0049] The gas that has passed through the first heat storage body 40a passes through the gas flow path L1 of the first cooler 33a, and is cooled to a temperature of 50°C or less. The gas that has passed through the first cooler 33a passes through the third extension part 31c of the gas line 31, flows into the second extension part 31b, and is introduced into the second heat storage body 40b. At this time, the cooling function of the second cooler 33b is turned off, so that the gas introduced into the second heat storage body 40b can be prevented from being cooled more than necessary.

[0050] Since the second heat storage body 40b is in a high temperature state due to the heat stored in it from the previous heat exchange, when the gas passes through the second heat storage body 40b, the gas is heated by heat exchange to a temperature of about 1150° C., which is close to the temperature in the heat treatment space 11. The gas that has passed through the second heat storage body 40b is ejected from the second suction ejection port 17 into the heat treatment space 11 and reaches the surfaces of the multiple workpieces 1 on the plate 2.

[0051] In Fig. 4(a), the arrows indicate the direction of gas flow when gas is sucked from the heat treatment space 11 to the gas line 31 through the first suction nozzle 16 and is ejected to the heat treatment space 11 through the second suction nozzle 17. As shown in Fig. 4(a), the flow direction of gas sucked from the heat treatment space 11 to the gas line 31 through the first suction nozzle 16 is opposite to the flow direction of gas ejected from the gas line 31 to the heat treatment space 11 through the second suction nozzle 17. Therefore, the inner product of the unit vector along the traveling direction of gas ejected from the gas line 31 to the heat treatment space 11 and the unit vector along the traveling direction of gas sucked from the heat treatment space 11 to the gas line 31 during the sucking and ejecting of gas through the gas line 31 is negative.

[0052] Since gas is ejected from the gas line 31 along the direction in which the gas line 31 extends toward the second suction nozzle 17, in the example shown in Fig. 4(a), the unit vector along the direction of travel of the gas ejected from the gas line 31 to the heat treatment space 11 means the unit vector along the direction in which the second extension 31b of the gas line 31 extends toward the second suction nozzle 17. Since gas sucked into the gas line 31 flows along the direction in which the gas line 31 extends, in the example shown in Fig. 4(a), the unit vector along the direction of travel of the gas sucked from the heat treatment space 11 to the gas line 31 means the unit vector along the direction in which the first extension 31a of the gas line 31 extends from the first suction nozzle 16.

[0053] Next, as shown in FIG. 4(b), when the second fan 32b is driven and the first fan 32a is deactivated, the gas in the heat treatment space 11 of the main body 10 is sucked from the second suction nozzle 17 to the second extension 31b of the gas line 31. At this time, the cooling function of the second cooler 33b arranged in the second extension 31b that serves as the gas suction flow path is turned on, and the cooling function of the first cooler 33a arranged in the first extension 31a that serves as the gas ejection flow path is turned off. The gas sucked from the heat treatment space 11 passes through the second heat storage body 40b arranged in the second extension 31b of the gas line 31, and at this time, heat exchange is performed, and the temperature drops to around 100°C. As a result, the second heat storage body 40b accumulates heat and becomes in a high-temperature state.

[0054] The gas that has passed through the second heat storage body 40b passes through the gas flow path L1 of the second cooler 33b, and is cooled to a temperature of 50°C or less. The gas that has passed through the second cooler 33b passes through the third extension 31c of the gas line 31, flows into the first extension 31a, and is introduced into the first heat storage body 40a. At this time, the cooling function of the first cooler 33a is turned off, so that the gas introduced into the first heat storage body 40a can be prevented from being cooled more than necessary.

[0055] Since the first heat storage body 40a is in a high temperature state due to the heat stored in it from the previous heat exchange, when the gas passes through the first heat storage body 40a, the gas is heated by heat exchange to a temperature of about 1150° C., which is close to the temperature in the heat treatment space 11. The gas that has passed through the first heat storage body 40a is ejected from the first suction ejection port 16 into the heat treatment space 11 and reaches the surfaces of the multiple workpieces 1 on the plate 2.

[0056] In Fig. 4(b), the arrows indicate the direction of gas flow when gas is sucked from the heat treatment space 11 to the gas line 31 through the second suction nozzle 17 and is ejected to the heat treatment space 11 through the first suction nozzle 16. As shown in Fig. 4(b), the flow direction of gas sucked from the heat treatment space 11 to the gas line 31 through the second suction nozzle 17 is opposite to the flow direction of gas ejected from the gas line 31 to the heat treatment space 11 through the first suction nozzle 16. Therefore, the inner product of the unit vector along the traveling direction of gas ejected from the gas line 31 to the heat treatment space 11 and the unit vector along the traveling direction of gas sucked from the heat treatment space 11 to the gas line 31 during the sucking and ejecting of gas through the gas line 31 is negative.

[0057] Since gas is ejected from the gas line 31 along the direction in which the gas line 31 extends toward the first suction nozzle 16, in the example shown in Fig. 4(b), the unit vector along the direction of travel of the gas ejected from the gas line 31 to the heat treatment space 11 means the unit vector along the direction in which the first extension 31a of the gas line 31 extends toward the first suction nozzle 16. Since gas sucked into the gas line 31 flows along the direction in which the gas line 31 extends, in the example shown in Fig. 4(b), the unit vector along the direction of travel of the gas sucked from the heat treatment space 11 to the gas line 31 means the unit vector along the direction in which the second extension 31b of the gas line 31 extends from the second suction nozzle 17.

[0058] Here, the above-described operation of suctioning and ejecting gas by driving the first fan 32a, and the operation of suctioning and ejecting gas by driving the second fan 32b are each defined as "one cycle."

[0059] The above-mentioned cycle, that is, the driving of the first fan 32a and the driving of the second fan 32b are repeated at regular intervals, so that the operation of sucking gas from one of the first suction nozzle 16 and the second suction nozzle 17 into the heat treatment space 11 and ejecting the gas from the other can be repeated. In this manner, in the heating furnace 100 of this embodiment, the suction and ejection of gas through the first suction nozzle 16 and the second suction nozzle 17 are switched by switching between driving and non-driving the first fan 32a and the second fan 32b, so that the suction and ejection of gas can be switched without using a valve. This allows the configuration of the heating furnace 100 to be made compact, and the cost to be reduced.

[0060] The first fan 32a and the second fan 32b can be controlled to any output by, for example, PWM control. Therefore, for example, the first fan 32a and the second fan 32b can be controlled so that the air volume increases and decreases repeatedly during one cycle. By repeatedly increasing and decreasing the air volume, a high gas ejection speed can be obtained instantaneously, and an entrainment phenomenon occurs in the heat treatment space 11, in which the high-temperature gas entrained in the ejected flow increases. As a result, 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 in the heat treatment space 11, so that the heat treatment reaction for each workpiece 1 can be made more uniform.

[0061] Here, the gas temperature at each point was investigated when the air volume of the fan 32 was changed. Here, a cylinder having a diameter of 30 mm and a length of 200 mm and having a honeycomb-shaped cell hole with a cell density of 400 CPSI was used as the heat storage body 40. The temperature inside the furnace was 800°C, and the gas was repeatedly sucked and ejected at 10 seconds / cycle, and the temperature of the gas that passed through the heat storage body 40 and ejected into the heat treatment space 11, the temperature of the gas that was sucked from the heat treatment space 11 and passed through the heat storage body 40, and the temperature of the gas that passed through the heat storage body 40 and flowed into the fan 32 were investigated. The results are shown in Table 1.

[0062] [Table 1]

[0063] As shown in Table 1, the airflow rate of the 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. Note that here, simple coolers were used instead of the first cooler 33a and the second cooler 33b, and the gas temperature was measured when both were operated with the cooling function turned on.

[0064] The air volume of the fan 32 was changed within a range of 14.4 L / min to 44.4 L / min, and the temperature of the gas ejected from the gas line 31 to the heat treatment space 11 was 770° C. or higher and 772° C. or lower. When the temperature of the inner wall of the main body 10 near the first suction jet port 16 and the second suction jet port 17 facing the heat treatment space 11 was measured, it was 783° C., so that the temperature of the gas ejected from the gas line 31 to the heat treatment space 11 was close to the temperature inside the furnace.

[0065] Furthermore, the temperature of the gas sucked from the heat treatment space 11 and passing through the heat storage body 40, and the temperature of the gas when it flows into the fan 32, increased as the air volume of the fan 32 increased. Note that, although it differs depending on the air volume of the fan 32, the temperature of the gas that passed through the heat storage body 40 decreases by about 8°C to 16°C before it flows into the fan 32. In this experimental example, when the air volume of the fan 32 was set to 44.4 L / min, the temperature of the gas when it flows into the fan 32 reached a maximum of 59°C, which is below the heat resistance temperature of the fan 32.

[0066] Even if the temperature inside the furnace is set to a temperature higher than 800°C, the temperature of the gas flowing into the fan 32 can be reduced to 60°C or lower by providing a cooler 33 with high heat exchange properties as in the heating furnace 100 of this embodiment.

[0067] Here, when the workpiece 1 is an unfired ceramic body for producing ceramic electronic components such as a multilayer ceramic capacitor, the heat treatment removes the binder and causes various reactions. The binder is, for example, carbon. For example, the binder in the ceramic body is thermally decomposed at a temperature of about 150°C, and is almost completely removed before the temperature exceeds 1000°C. However, even at temperatures exceeding 600°C, it is desirable to quickly remove the components remaining inside. For example, it is known that if the temperature inside the furnace reaches the maximum temperature in a state where the binder has not been completely removed, structural defects and quality deterioration of the manufactured ceramic electronic components will occur. Therefore, it is important to quickly remove the binder.

[0068] Generally, gas flow is effective in removing binders, so it is desirable to supply gas with a necessary and sufficient flow rate to the vicinity of the workpiece 1. By supplying gas with a necessary and sufficient flow rate to the vicinity of the workpiece 1, the concentration of the scattered gas containing the debris from the inside of the workpiece 1 in the vicinity of the workpiece 1 is reduced, facilitating the removal of the debris from the inside of the workpiece 1. Conversely, if the gas flow rate is low, the removal of the debris from the inside of the workpiece 1 becomes difficult to proceed.

[0069] In the heating furnace 100 of this embodiment, the suction and ejection unit 30 repeatedly sucks gas from the heat treatment space 11 into the gas line 31 and ejects the gas sucked into the gas line 31 into the heat treatment space 11, thereby making it possible to supply gas at a necessary and sufficient flow rate to the vicinity of the workpiece 1 without the need to introduce new gas from outside the furnace. Since the gas ejected from the gas line 31 into the heat treatment space 11 has the same composition as the gas in the heat treatment space 11, it is possible to suppress the occurrence of reaction variations between the workpiece 1 at a position where the gas ejected from the gas line 31 hits and the workpiece 1 at a position where the gas ejected from the gas line 31 does not hit.

[0070] Furthermore, in the heating furnace 100 of this embodiment, the heat storage body 40 is arranged in a portion of the gas line 31 that is located inside the main body 10, so that the temperature of the gas ejected from the gas line 31 into the heat treatment space 11 can be made closer to the temperature of the gas in the heat treatment space 11, compared to a configuration in which the heat storage body 40 is arranged outside the main body 10.

[0071] The above-mentioned removal of the binder will be described with a more specific example. Here, an example will be described in which carbon, which is a binder, is present in the processing target 1 and the carbon is removed by burning it. Carbon can be removed by the following reaction formula (1). C+2H2O → CO2+2H2(1)

[0072] The reaction according to formula (1) is known as the water-gas reaction, and is generally carried out to remove carbon at high temperatures of approximately 600°C or higher. In this reaction, as shown in formula (1), H2 gas is also generated in addition to CO2 generated by the combustion of carbon. According to the law of mass action, if the CO2 concentration or H2 concentration in or near the workpiece 1 becomes high, it acts to suppress the reaction shown in formula (1).

[0073] Therefore, during the process of burning carbon, it is necessary to maintain low CO2 and H2 concentrations in the workpiece 1 or in the vicinity of the workpiece 1. To achieve this, it is necessary to constantly supply fresh gas, that is, gas with low concentrations of CO2 gas and H2 gas, which is the gas generated by formula (1), toward the workpiece 1. However, under conditions where the gas flow rate is low and the gas flow rate around the workpiece 1 is low, the generated gas remains in the workpiece 1 or in the vicinity of the workpiece 1, making it difficult for the reaction shown in formula (1) to proceed.

[0074] In contrast, when the heating furnace 100 of the present embodiment is used, the suction and ejection unit 30 sucks gas from the heat treatment space 11 of the main body 10 into the gas line 31, and the gas with the same composition as the gas in the heat treatment space 11 and at a temperature close to the temperature of the gas in the heat treatment space 11 is repeatedly ejected toward the workpiece 1, so that a flow of gas several tens of times larger can be formed in the vicinity of the workpiece 1 compared to a configuration without the suction and ejection unit 30. Therefore, the flow rate of gas flowing in the vicinity of the workpiece 1 is increased, and the flow rate of gas in the vicinity of the workpiece 1 is increased, so that the CO2 gas and H2 gas generated by the reaction of formula (1) are prevented from accumulating in the workpiece 1 or in the vicinity of the workpiece 1, and the concentrations of CO2 gas and H2 gas in the workpiece 1 or in the vicinity of the workpiece 1 can be reduced. Therefore, the reaction shown in formula (1) is easily promoted, so that the removal of carbon in the workpiece 1 proceeds quickly, and the variation in the amount of residual carbon for each workpiece 1 can be suppressed. This makes it possible to obtain high-quality products with less residual carbon.

[0075] <Second embodiment> 5 is a cross-sectional view showing a schematic configuration of a heating furnace 100A according to the second embodiment. The heating furnace 100A according to the second embodiment differs from the heating furnace 100 according to the first embodiment in the configuration of the suction and jetting part 30.

[0076] In the heating furnace 100A of this embodiment, the suction / jet unit 30 further includes a third fan 32c and a fourth fan 32d in addition to the configuration of the suction / jet unit 30 of the first embodiment. The third fan 32c and the fourth fan 32d may have any structure as long as they are capable of blowing air, similar to the first fan 32a and the second fan 32b.

[0077] The third fan 32c is disposed in the first extension 31a of the gas line 31, and is a fan for flowing gas in a direction opposite to the gas flow caused by the driving of the first fan 32a. As described above, the first fan 32a is disposed so that the gas flows from the first extension 31a to the third extension 31c when driven, and therefore the third fan 32c is disposed so that the gas flows from the third extension 31c to the first extension 31a when driven.

[0078] In this embodiment, the first fan 32a and the third fan 32c are arranged so that the gas generated by driving one of the fans flows toward the other fan. As described above, the first fan 32a is arranged so that the gas flows from the first extension portion 31a to the third extension portion 31c when the first fan 32a is driven, and therefore the third fan 32c is provided at a position on the first extension portion 31a of the gas line 31 opposite the first cooler 33a with respect to the first fan 32a. With such an arrangement, the gas generated by driving the first fan 32a flows toward the third fan 32c, and the gas generated by driving the third fan 32c flows toward the first fan 32a.

[0079] The fourth fan 32d is disposed in the second extension portion 31b of the gas line 31, and is a fan for flowing gas in a direction opposite to the gas flow caused by the driving of the second fan 32b. As described above, the second fan 32b is disposed so that the gas flows from the second extension portion 31b to the third extension portion 31c when driven, and therefore the third fan 32c is disposed so that the gas flows from the third extension portion 31c to the second extension portion 31b when driven.

[0080] In this embodiment, the second fan 32b and the fourth fan 32d are arranged so that the gas generated by driving one of the fans flows toward the other fan. As described above, the second fan 32b is arranged so that the gas flows from the second extension portion 31b to the third extension portion 31c when the second fan 32b is driven, and therefore the fourth fan 32d is provided at a position on the second extension portion 31b of the gas line 31 opposite the second cooler 33b with respect to the second fan 32b. With such an arrangement, the gas generated by driving the second fan 32b flows toward the fourth fan 32d, and the gas generated by driving the fourth fan 32d flows toward the second fan 32b.

[0081] In this way, by providing two fans in which the gas flows in opposite directions in each of the first extension 31a and the second extension 31b of the gas line 31, it is possible to distribute the load of the pressure loss caused by the driving of the fans to the two fans. This makes it possible to reduce the size of the fan 32 provided in the gas line 31.

[0082] Here, the gas suction and ejection operations through the gas line 31 of the heating furnace 100A in the second embodiment will be described. When the gas in the heat treatment space 11 of the main body 10 is sucked from the first suction ejection port 16 to the gas line 31, as shown in Fig. 6(a), the first fan 32a and the fourth fan 32d are driven, and the second fan 32b and the third fan 32c are deactivated. At this time, the cooling function of the first cooler 33a is turned on, and the cooling function of the second cooler 33b is turned off.

[0083] Conversely, when gas in the heat treatment space 11 of the main body 10 is sucked from the second suction nozzle 17 to the gas line 31, the second fan 32b and the third fan 32c are driven and the first fan 32a and the fourth fan 32d are deactivated, as shown in Fig. 6(b). At this time, the cooling function of the first cooler 33a is turned off and the cooling function of the second cooler 33b is turned on.

[0084] Here, it is also possible to reverse the arrangement of the first fan 32a and the third fan 32c. However, the inventors' experiments have revealed that such an arrangement increases the pressure loss caused by the non-driven fan 32. Therefore, as in this embodiment, it is preferable to arrange the first fan 32a and the third fan 32c so that the gas generated by driving one of the fans flows toward the other fan.

[0085] Similarly, it is possible to reverse the arrangement of the second fan 32b and the fourth fan 32d, but in order to reduce pressure loss, it is preferable to arrange them so that gas produced by driving one of the second fan 32b and the fourth fan 32d is directed toward the other fan, as in this embodiment.

[0086] In the heating furnace 100A of this embodiment, as in the heating furnace 100 of the first embodiment, the path length of the gas line 31 can be shortened, and the overall configuration of the heating furnace 100A can be made compact. This also applies to the heating furnaces in all the embodiments described below.

[0087] <Third embodiment> In the heating furnace 100 in the first embodiment and the heating furnace 100A in the second embodiment, the gas line 31 is composed of a first extension portion 31a, a second extension portion 31b, and a third extension portion 31c, which are portions extending horizontally.

[0088] In contrast, in the heating furnace 100B of the third embodiment, the gas line 31 includes a portion extending in the horizontal direction and a portion extending in the vertical direction.

[0089] In the heating furnace 100B of this embodiment, the suction and jetting part 30 includes not only the first fan 32a and the second fan 32b, but also the third fan 32c and the fourth fan 32d, as in the heating furnace 100A of the second embodiment. However, the third fan 32c and the fourth fan 32d may be omitted.

[0090] Fig. 7 is a cross-sectional view showing a schematic configuration of a heating furnace 100B in a third embodiment. Like Fig. 1, Fig. 7 shows a cross section of the heating furnace 100B cut along a plane perpendicular to the transport direction of the workpiece 1. Fig. 8 is a diagram showing a schematic configuration of the heating furnace 100B shown in Fig. 7 as viewed from the direction of the arrow Y1.

[0091] 5 is bent upward at a position midway between the first extension portion 31a and the third extension portion 31c. That is, the gas line 31 in this embodiment also includes the first extension portion 31a, the second extension portion 31b, and the third extension portion 31c, but the shapes of the first extension portion 31a and the second extension portion 31b are different from those of the gas line 31 shown in FIG.

[0092] In this embodiment, the first extension portion 31a has a first horizontal portion 31a1 which is a portion extending 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 is a portion extending vertically.

[0093] In this embodiment, the second extension portion 31b 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.

[0094] The third extension portion 31c extends in the horizontal direction and connects the first vertical portion 31a2 of the first extension portion 31a and the second vertical portion 31b2 of the second extension portion 31b.

[0095] The first heat storage body 40a is disposed in a first horizontal section 31a1, which is a section extending in the horizontal direction, of the first extension section 31a of the gas line 31. The second heat storage body 40b is disposed in a second horizontal section 31b1, which is a section extending in the horizontal direction, of the second extension section 31b of the gas line 31. In the present embodiment, the first heat storage body 40a and the second heat storage body 40b are also provided in a region penetrating the main body 10 within the gas line 31.

[0096] 8, the first cooler 33a, the first fan 32a, and the third fan 32c are disposed in a first vertical section 31a2, which is a section extending in the vertical direction, of the first extension section 31a of the gas line 31. The relative positional relationship between 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.

[0097] The gas flowing through the gas line 31 is cooled by the first cooler 33a whose cooling function is on. When the temperature of the cooled gas falls below the dew point, the water vapor contained in the gas condenses and adheres to the surface. In the heating furnace 100B of this embodiment, the first cooler 33a is disposed in the first vertical portion 31a2 of the gas line 31, so that the condensed water adhering to the surface of the first cooler 33a can be dropped. This makes it possible to prevent the condensed water from remaining attached to the surface of the first cooler 33a.

[0098] 8, the second cooler 33b, the second fan 32b, and the fourth fan 32d are disposed in a second vertical section 31b2, which is a section extending in the vertical direction, of the second extension section 31b of the gas line 31. The relative positional relationship 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.

[0099] The gas flowing through the gas line 31 is cooled by the second cooler 33b whose cooling function is on. When the temperature of the cooled gas falls below the dew point, the water vapor contained in the gas condenses and adheres to the surface. In the heating furnace 100B of this embodiment, the second cooler 33b is disposed in the second vertical section 31b2 of the gas line 31, so that the condensed water adhering to the surface of the second cooler 33b can be dropped. This makes it possible to prevent the condensed water from remaining attached to the surface of the second cooler 33b.

[0100] The heating furnace 100B in this embodiment further includes an evaporator 34 arranged vertically below the cooler 33 inside the gas line 31 for evaporating water. The evaporator 34 is a heat sink made of, for example, a metal such as aluminum, iron, or copper, or ceramic, and has fins. The surface of the heat sink may be porous. However, the evaporator 34 is not limited to a heat sink as long as it can evaporate water. In this embodiment, the evaporator 34 includes a first evaporator 34a and a second evaporator 34b.

[0101] The first evaporator 34a is disposed in the gas line 31, vertically below the first cooler 33a, at a portion where the first horizontal portion 31a1 and the first vertical portion 31a2 are connected. The first evaporator 34a is disposed to evaporate condensed water that is generated on the surface of the first cooler 33a and then drops down.

[0102] The second evaporator 34b is disposed in the gas line 31, vertically below the second cooler 33b, at a portion where the second horizontal portion 31b1 and the second vertical portion 31b2 are connected. The second evaporator 34b is disposed to evaporate condensed water that is generated on the surface of the second cooler 33b and then drops down.

[0103] As an example, if the dew point of the gas sucked into the gas line 31 from the heat treatment space 11 at 30 L / min is 60° C., the amount of condensation when cooled to 50° C. by the cooler 33 corresponds to 2.3 ccm. When switching between gas suction and ejection in one cycle of 10 seconds, approximately 0.4 cc of condensation is generated per cycle and adheres to the surface of the cooler 33.

[0104] When the gas suction and ejection are switched at predetermined time intervals by controlling the fan 32, the condensed water moves with the switched gas flow to the higher temperature side in the cooler 33 or falls downward. The condensed water that falls downward comes into contact with the evaporator 34 and vaporizes, and flows again into the heat treatment space 11 of the main body 10 as water vapor.

[0105] As described above, according to the heating furnace 100B of the third embodiment, the gas line 31 includes a portion extending in the horizontal direction and a portion extending in the vertical direction, and the cooler 33 is disposed in the portion extending in the vertical direction, so that the condensation water generated on the surface of the cooler 33 can be dropped. This makes it possible to prevent the condensation water from remaining attached to the surface of the cooler 33.

[0106] Furthermore, the heating furnace 100B in the third embodiment is provided with an evaporator 34 for evaporating water, which is disposed vertically below the cooler 33 inside the gas line 31, and can quickly evaporate condensed water that has fallen from the surface of the cooler 33. This allows the condensed water to be quickly returned to the heat treatment space 11 without being retained inside the gas line 31, and therefore allows gas having the same components as the gas sucked from the heat treatment space 11 to the gas line 31 to be ejected from the gas line 31 to the heat treatment space 11.

[0107] If the condensed water that forms on the surface of the cooler 33 and drops therefrom is evaporated inside the gas line 31, the vaporizer 34 can be omitted.

[0108] <Fourth embodiment> FIG. 9 is a cross-sectional view showing a schematic configuration of a heating furnace 100C in the fourth embodiment. The cutting position of the cross-sectional view shown in FIG. 9 is the same as the cutting position of the cross-sectional view shown in FIG. 2. In the heating furnace 100C in this embodiment, the suction and jetting part 30 includes not only the first fan 32a and the second fan 32b, but also the third fan 32c and the fourth fan 32d, as in the heating furnace 100A in the second embodiment. However, the third fan 32c and the fourth fan 32d may be omitted.

[0109] The heating furnace 100C in the fourth embodiment differs from the heating furnace 100A in the second embodiment in the heat storage body 40. That is, the heat storage body 40 in the fourth embodiment is partially exposed in the heat treatment space 11 of the main body 10. As in 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, and a portion of each of the first heat storage body 40a and the second heat storage body 40b is exposed in the heat treatment space 11.

[0110] The length of the heat storage body 40 that protrudes and is exposed in the heat treatment space 11 of the main body 10 may 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.

[0111] Since a part of the first heat storage body 40a is exposed in the heat treatment space 11, the part of the first heat storage body 40a exposed in the heat treatment space 11 is at a higher temperature than the part not exposed. Therefore, the gas passing through the first heat storage body 40a and ejected 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 part of the second heat storage body 40b is exposed in the heat treatment space 11, the gas passing through the second heat storage body 40b and ejected into the heat treatment space 11 is ejected at a higher temperature due to heat exchange with the second heat storage body 40b. This makes it possible to make the temperature of the gas ejected into the heat treatment space 11 closer to the temperature of the gas in the heat treatment space 11, and to further suppress the variation in the reaction between the object 1 and the gas.

[0112] <Fifth embodiment> In the heating furnace 100 of the first embodiment, gas is jetted horizontally from the first suction jet 16 and the second suction jet 17 of the gas line 31. For this reason, it is preferable that the first suction jet 16 and the second suction jet 17 are provided at a position as close as possible to the height of the driving roller 13 on which the plate 2 is placed, so that the gas is jetted toward the plurality of workpieces 1 on the plate 2.

[0113] 1, 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 to which the gas line 31 is connected. Therefore, if the first suction jet 16 and the second suction jet 17 are located at a height position as close as possible to the drive roller 13, there is a possibility that the drive unit of the drive roller 13 and the gas line 31 will interfere with each other, which requires some ingenuity in the design.

[0114] For this reason, in the heating furnace 100D in the fifth embodiment, the first suction jet 16 and the second suction jet 17 are provided at positions away from the drive portion of the drive roller 13.

[0115] Fig. 10 is a cross-sectional view showing a schematic configuration of a heating furnace 100D according to the fifth embodiment. Like Fig. 1, Fig. 10 shows a cross section of the heating furnace 100D taken along a plane perpendicular to the transport direction of the workpiece 1.

[0116] Compared with the heating furnace 100 in the first embodiment, the first suction jet 16 in this embodiment is provided at a higher position relative to the driving roller 13, that is, at a position farther away from the driving roller 13 in the height direction perpendicular to the conveying surface of the driving roller 13. Although not shown in the figure, the same is true for the second suction jet 17. With such an arrangement, interference between the driving part of the driving roller 13 and the gas line 31 can be suppressed.

[0117] 10, in the heating furnace 100D of this embodiment, like the heating furnace 100C of the fourth embodiment, a part of the first heat storage body 40a is exposed in the heat treatment space 11. Similarly, a part of the second heat storage body 40b is exposed in the heat treatment space 11. However, a configuration in which a part of the first heat storage body 40a and a part of the second heat storage body 40b are not exposed in the heat treatment space 11 is also possible.

[0118] In this embodiment, the gas line 31 is arranged so that the inner product of a unit normal vector extending to the side where the workpiece 1 is placed relative to the placement surface on which the workpiece 1 is placed in the heat treatment space 11 and a unit vector along the traveling direction of the gas ejected from the gas line 31 into the heat treatment space 11 is negative. This will be described with reference to FIG.

[0119] In addition, since gas is ejected from gas line 31 in the direction in which gas line 31 extends toward its tip, a unit vector along the direction of travel of gas ejected from gas line 31 into heat treatment space 11 means a unit vector along the direction in which gas line 31 extends toward its tip.

[0120] 11 is a diagram showing the relationship between a unit vector v along the traveling direction of the gas ejected from the first extension 31a of the gas line 31 through the first suction nozzle 16 into the heat treatment space 11, and a unit normal vector n extending toward the side on which the workpiece 1 is placed, with respect to the mounting 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 direction of the first extension 31a of the gas line 31 is adjusted so that the gas is ejected from the gas line 31 obliquely downward through the first suction nozzle 16.

[0121] Although not shown in the figure, the inner product (v·n) of a unit vector v along the traveling direction of the gas ejected from the second extension 31b of the gas line 31 through the second suction nozzle 17 into the heat treatment space 11 and a unit normal vector n extending toward the side on which the workpiece 1 is placed, with respect to the mounting surface 2a of the plate 2 on which the workpiece 1 is placed, is also negative. In other words, the orientation of the second extension 31b of the gas line 31 is adjusted so that the gas is ejected from the gas line 31 obliquely downward through the second suction nozzle 17.

[0122] According to the heating furnace 100D of the fifth embodiment, it is possible to suppress interference between the drive part of the drive roller 13 and the gas line 31. In addition, since gas is blown from diagonally above onto the multiple workpieces 1 on the plate 2 in the heat treatment space 11, it is possible to blow gas onto a larger number of workpieces 1. This makes it possible to promote reactions on a larger number of workpieces 1, and further suppress variation in reactions between the workpieces 1.

[0123] Sixth embodiment Fig. 12 is a cross-sectional view that shows a schematic configuration of a heating furnace 100E in the sixth embodiment, and Fig. 13 is an enlarged cross-sectional view of a portion of a gas line 31 near a first suction jet nozzle 16.

[0124] 13, the cross-sectional area of ​​the first extension portion 31a of the gas line 31 becomes smaller toward the first suction jet port 16. More specifically, among the cross-sectional areas when the first extension portion 31a of the gas line 31 is cut along a plane perpendicular to the extension direction, the cross-sectional area Si of the tip 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 arranged.

[0125] Although not shown in the figure, the same is true for the second suction nozzle 17 side of the gas line 31. That is, the cross-sectional area of ​​the second extension portion 31b of the gas line 31 becomes smaller toward the tip on the heat treatment space 11 side. More specifically, among the cross-sectional areas when the second extension portion 31b of the gas line 31 is cut along a plane perpendicular to the extension direction, the cross-sectional area Si of the tip on 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 arranged.

[0126] In this way, the cross-sectional area of ​​the gas line 31 becomes smaller toward the end on the heat treatment space 11 side, so that the flow rate of the gas increases when it is ejected from the gas line 31 into the heat treatment space 11. This allows a gas flow with a higher flow rate to be formed in the vicinity of the workpiece 1, so that the heat treatment reaction can be further promoted and the reaction variation for each workpiece 1 can be further suppressed. Therefore, the quality variation of the product obtained by the heat treatment of the workpiece 1 can be further suppressed.

[0127] Furthermore, as the flow velocity of the gas ejected into the heat treatment space 11 increases, an entrainment phenomenon occurs in which an increase in the amount of high-temperature gas caught in the ejected flow occurs in the heat treatment space 11. As a result, 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 in the heat treatment space 11, so that the reaction variation for each workpiece 1 can be further suppressed.

[0128] <Seventh embodiment> In the heating furnace 100 in the first embodiment to the heating furnace 100E in the sixth embodiment, the main body 10 is a substantially rectangular parallelepiped with both ends open in the transport direction of the workpiece 1. In contrast, in the heating furnace 100F in the seventh embodiment, the main body 10 has a substantially spherical shape.

[0129] In the heating furnace 100F of this embodiment, like the heating furnace 100A of the second embodiment, the suction and jetting part 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, the third fan 32c and the fourth fan 32d may be omitted.

[0130] 14 is a cross-sectional view showing a schematic configuration of a heating furnace 100F according to the seventh embodiment. The cut position of the cross-sectional view shown in FIG.

[0131] In the heating furnace 100F of this embodiment, the gas line 31 is also arranged so that the inner product of the unit vector along the direction of travel of the gas ejected from the gas line 31 to the heat treatment space 11 and the unit vector along the direction of travel of the gas ejected from the heat treatment space 11 to the gas line 31 is equal to or less than 0 during the gas ejection and ejection. In order to shorten the path length of the gas line 31, it is preferable to arrange the gas line 31 so that the positions of the first suction jet 16 and the second suction jet 17 are close to each other. In FIG. 14, the arrows indicate the flow of gas when the gas is sucked from the heat treatment space 11 to the gas line 31 through the first suction jet 16 and ejected to the heat treatment space 11 through the second suction jet 17.

[0132] In the heating furnace 100F of the seventh embodiment, the gas line 31 is also arranged so that the inner product of the unit vector along the traveling direction of the gas ejected from the gas line 31 to the heat treatment space 11 and the unit vector along the traveling direction of the gas sucked from the heat treatment space 11 to the gas line 31 is equal to or less than 0 during the gas intake and ejection, so that the path length of the gas line 31 can be shortened and the configuration of the heating furnace 100F can be made compact. Furthermore, by shortening the path length of the gas line 31, heat radiation to the outside of the flow path when the gas flows through the gas line 31 can be suppressed, and thermal efficiency can be improved.

[0133] <Eighth embodiment> Each of the heating furnaces 100 in the first embodiment to the heating furnace 100F in the seventh embodiment is provided with one suction and jetting part 30. In contrast, the heating furnace 100G in the eighth embodiment is provided with a plurality of suction and jetting parts 30.

[0134] 15 is a cross-sectional view showing a schematic configuration of a heating furnace 100G according to the eighth embodiment. The cut position of the cross-sectional view shown in FIG. 15 is the same as the cut position of the cross-sectional view shown in FIG.

[0135] 15, four suction jetting portions 30 are provided. Specifically, two suction jetting portions 30 are provided on the first side wall 10a of the main body portion 10, and two suction jetting portions 30 are provided on the second side wall 10b opposite the first side wall 10a. However, the number of suction jetting portions 30 is not limited to four, and all of the suction jetting portions 30 may be provided on one side wall.

[0136] According to the present invention, the gas line 31 is arranged so that the inner product of the unit vector along the traveling direction of the gas ejected from the gas line 31 to the heat treatment space 11 and the unit vector along the traveling direction of the gas sucked from the heat treatment space 11 to the gas line 31 is equal to or less than 0, thereby shortening the path length of the gas line 31 and making it possible to provide a plurality of suction and ejection parts 30. This makes it possible to further suppress the reaction variation of the workpiece 1.

[0137] The suction jetting section 30 provided on the first side wall 10a of the main body 10 and the suction jetting section 30 provided on the second side wall 10b are preferably provided at positions facing each other. More specifically, it is preferable that the first suction jetting port 16 of the gas line 31 connected to the second side wall 10b is located at a position facing the first suction jetting port 16 of the gas line 31 connected to the first side wall 10a of the main body 10, and the second suction jetting port 17 of the gas line 31 connected to the second side wall 10b is located at a position facing the second suction jetting port 17 of the gas line 31 connected to the first side wall 10a.

[0138] Furthermore, it is preferable to control the suction jetting part 30 so that the gas flows in the same direction in the direction in which the first side wall 10a and the second side wall 10b face each other, as shown in FIG. 15. In the example shown in FIG. 15, the arrows indicate the gas flow when the gas is sucked from the first suction jetting port 16 of the gas line 31 connected to the first side wall 10a and is jetted from the second suction jetting port 17. The arrows indicate the gas flow when the gas is jetted from the first suction jetting port 16 of the gas line 31 connected to the second side wall 10b and is sucked from the second suction jetting port 17. In this way, by controlling the suction and jetting of the gas, the gas can be sucked at the same time at the position in the straight direction of the gas jetted into the heat treatment space 11, so that the straightness of more gas can be maintained among the gas jetted from the gas line 31 into the heat treatment space 11. This allows the gas to flow over and near the surfaces of a greater number of objects 1 to be treated, making it possible to further suppress variations in the reaction during heat treatment for each object 1 to be treated.

[0139] The present invention is not limited to the above-described embodiment, and various applications and modifications can be made within the scope of the present invention. For example, the characteristic configurations of the heating furnace in each embodiment can be appropriately combined.

[0140] The shape of the main body 10 is not limited to the shapes described in the above-mentioned embodiments. Even if the shape of the main body 10 is a shape other than the above-mentioned substantially rectangular parallelepiped shape or substantially spherical shape, the gas line 31 may be arranged so that the inner product of a unit vector along the traveling direction of the gas ejected from the gas line 31 to the heat treatment space 11 and a unit vector along the traveling direction of the gas sucked from the heat treatment space 11 to the gas line 31 during the intake and ejection of the gas via the gas line 31 is equal to or less than 0.

[0141] In each of the above-described embodiments, the suction / jet unit 30 is provided with the fan 32, and the fan 32 is driven to suction gas from the heat treatment space 11 into the gas line 31 and to jet the gas from the gas line 31 into the heat treatment space 11. However, the power source for suctioning and jetting the gas is not limited to the fan 32. For example, a piston may be disposed in the gas line 31, and the gas may be suctioned and jetted by a movable part reciprocating inside the cylinder of the piston. [Explanation of symbols]

[0142] 1. Workpiece 10 Main body 11 Heat treatment space 12 Heating section 13 Drive roller 14 Gas supply port 15 Gas exhaust port 16 First suction nozzle 17 Second suction nozzle 20 Gas supply section 30 Suction spout part 31 Gas Line 31a First extension part 31a1 First horizontal section 31a2 First vertical section 31b Second extension part 31b1 Second horizontal section 31b2 Second vertical section 31c Third extension 32a The First Fan 32b Second Fan 32c The Third Fan 32d The Fourth Fan 33a First Cooler 33b Second Cooler 34a First Carburetor 34b Second Carburetor 40a First heat storage body 40b Second heat storage body 100,100A,100B,100C,100D,100E,100F,100G Heating furnace L1 Gas flow path L2 Coolant flow path

Claims

1. a main body having a heat treatment space for performing heat treatment on an object to be treated and including a heating unit disposed within the heat treatment space; a gas supply unit that supplies a gas necessary for performing heat treatment to the heat treatment space of the main body; a suction / blowout unit having a gas line connected to the main body, the suction unit repeatedly sucking gas from the heat treatment space into the gas line and blowing the gas sucked into the gas line into the heat treatment space; A heat storage body capable of exchanging heat is disposed inside the gas line; Equipped with the gas line is arranged such that, when gas is sucked in and ejected through the gas line, an inner product of a unit vector along a traveling direction of the gas ejected from the gas line to the heat treatment space and a unit vector along a traveling direction of the gas sucked from the heat treatment space to the gas line is equal to or less than 0; the gas line includes a first extension portion extending from a first suction jet located at one end toward the outside of the body portion, and a second extension portion extending from a second suction jet located at the other end toward the outside of the body portion, the suction and jetting section includes a first fan disposed in the first extension section and a second fan disposed in the second extension section, The gas supply system further includes a cooler disposed in the gas line for cooling the gas that has been drawn from the heat treatment space and passed through the heat storage body; The heat storage body includes a first heat storage body arranged in the first extension portion and a second heat storage body arranged in the second extension portion, The heating furnace is characterized in that the coolers include a first cooler arranged between the first heat storage body and the first fan, and a second cooler arranged between the second heat storage body and the second fan.

2. 2. The heating furnace according to claim 1, wherein the heat storage body is provided in a portion of the inside of the gas line that is located inside the main body.

3. 3. The heating furnace according to claim 2, wherein the heat storage body is provided in an area inside the gas line that penetrates the main body.

4. 4. The heating furnace according to claim 1, wherein 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 4, characterized in that the gas line is arranged so that the dot product of a unit normal vector extending toward the side on which the workpiece is placed, with respect to a placement surface on which the workpiece is placed in the heat treatment space, and a unit vector along a traveling direction of the gas ejected from the gas line into the heat treatment space, is negative.

6. A heating furnace as described in any one of claims 1 to 5, characterized in that, among the cross-sectional areas when the gas line is cut along a plane perpendicular to the extension direction, the cross-sectional area of ​​the end on the heat treatment space side is smaller than the average cross-sectional area of ​​the region in which the heat storage body is located.

7. The heating furnace as described in claim 1, characterized in that the suction and jetting section further comprises a third fan arranged in the first extension section for flowing gas in a direction opposite to the gas flow caused by the drive of the first fan, and a fourth fan arranged in the second extension section for flowing gas in a direction opposite to the gas flow caused by the drive of the second fan.

8. the first fan and the third fan are arranged such that gas generated by driving one of the fans is directed toward the other fan, 8. The heating furnace according to claim 7, wherein the second fan and the fourth fan are arranged so that gas generated by driving one of the fans flows toward the other fan.

9. 2. The heating furnace according to claim 1, wherein the cooler is a heat exchanger in which gas flow passages through which gas flows and refrigerant flow passages through which a refrigerant flows are alternately stacked.

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 serving as a gas intake passage, of the first extension and the second extension of the gas line, is turned on, and the cooling function of the cooler disposed in the extension serving as a gas ejection passage is turned off.

11. The gas line includes a portion extending in a horizontal direction and a portion extending in a vertical direction, 11. A heating furnace as claimed in any one of claims 1, 9 and 10, characterized in that the heat storage body is arranged in a portion of the gas line extending in the horizontal direction, and the cooler is arranged in a portion of the gas line extending in the vertical direction.

12. 12. The heating furnace according to claim 11, further comprising an evaporator for evaporating water, the evaporator being disposed vertically below the cooler inside the gas line.

13. 13. The heating furnace according to claim 1, wherein a plurality of the suction and jetting portions are provided.

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