JP2012097969A - Heating furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heating furnace that can equally heat up an object to be heated without complicating the structure and depending on the position in a heat treatment chamber while suppressing a heat loss.SOLUTION: A hot air generating circulation part 20 is connected with a heat treatment chamber 10 via a wind direction switching valve 60 and air supply/exhaust flow passages 30 and 40. The first air supply/exhaust flow passage 30 is connected with one side of the heat treatment chamber 10 and the second air supply/exhaust flow passage 40 is connected with the other side of the heat treatment chamber 10. When the wind direction switching valve 60 is switched to the first status, the air supply hot air PW from the hot air generating circulation part 20 passes toward the second air supply/exhaust flow passage 40 from the first air supply/exhaust flow passage 30 in the heat treatment chamber 10. In addition, when the wind direction switching valve 60 is switched to the second status, the air supply hot air PW from the hot air generating circulation part 20 passes toward the first air supply/exhaust flow passage 30 from the second air supply/exhaust flow passage 40 in the heat treatment chamber 10.

Description

  The present invention relates to a heating furnace that supplies hot air to a heat treatment chamber.

  As a conventional heating furnace, for example, a continuous debinding furnace for manufacturing electronic components as in Patent Document 1 is known. This heating furnace circulates the hot air generated by the hot air generator in the furnace and heats the ceramic molded body of the electronic component placed on the setter in the heat treatment chamber by hot air, thereby binding the binder contained in the ceramic molded body. Ingredients are removed. In this heating furnace, the hot air circulates in one direction in the furnace.

JP 2003-097888 A

  However, in the heating furnace described above, hot air circulates in one direction in the furnace. That is, in the heat treatment chamber, the upstream and downstream of the hot air flow are determined. Since the amount of heat supplied to the upstream side of the heat treatment chamber is larger than that on the downstream side, the heated state (degreasing state) between the ceramic molded body disposed on the upstream side and the ceramic molded body disposed on the downstream side. There will be a difference. As a result, in the ceramic molded body heat-treated in a conventional heating furnace, defects such as cracks and deformation occurred during firing. Therefore, it has been required to make the heating state of the object to be heated uniform regardless of the arrangement in the heat treatment chamber. Further, there has been a demand for uniform heating without complicating the structure of the heating furnace and without increasing heat loss.

  The present invention has been made in order to solve such problems. The object to be heated is uniformly heated regardless of the position in the heat treatment chamber without complicating the configuration and suppressing heat loss. It aims at providing the heating furnace which can do.

  A heating furnace according to the present invention is provided independently of the heat treatment chamber, a heat treatment chamber for performing heat treatment of an object to be heated, a hot air generating circulation section for generating hot air and supplying and exhausting the heat treatment chamber, and a heat treatment chamber. A first air supply / exhaust flow path that is connected to one side of the heat treatment chamber and connects the heat treatment chamber and the hot air generation circulation section, and is provided independently from the heat treatment chamber and the first air supply / exhaust flow path, and is connected to the other side of the heat treatment chamber And a second air supply / exhaust flow path connecting the heat treatment chamber and the hot air generating / circulating portion, a first air supply / exhaust flow path, A hot air generation and circulation section, and a wind direction switching valve that connects the second air supply and exhaust passage and the hot air generation and circulation section, and the hot air generation and circulation section includes an air supply passage that allows the hot air supplied to the heat treatment chamber to pass through. An exhaust passage for passing hot air exhausted from the heat treatment chamber, and an air supply passage A heat supply source disposed between the air flow path and an air blowing unit disposed at any position in the air supply flow path and the exhaust flow path, and the wind direction switching valve is provided in the air flow path of the hot air generating and circulating unit. And a first state in which the first air supply / exhaust flow path is the air supply side and the second air supply / exhaust flow path is the exhaust side, and the first air supply / exhaust flow path is the exhaust side And a second state in which the second air supply / exhaust flow path is set to the air supply side.

  According to the heating furnace according to the present invention, the hot air generation / circulation part is connected to the heat treatment chamber via the wind direction switching valve, the first supply / exhaust flow path, and the second supply / exhaust flow path. The first air supply / exhaust flow path is connected to one side of the heat treatment chamber, and the second air supply / exhaust flow path is connected to the other side of the heat treatment chamber. When the air direction switching valve is switched to the first state, the first air supply / exhaust flow path becomes the air supply side and the second air supply / exhaust flow path becomes the exhaust side, and the hot air supplied from the hot air generation circulation section is supplied to the first air supply in the heat treatment chamber. Passes from the exhaust passage toward the second supply / exhaust passage. When the air direction switching valve is switched to the second state, the first air supply / exhaust flow path becomes the exhaust side and the second air supply / exhaust flow path becomes the air supply side. Passes from the two air supply / exhaust flow paths toward the first air supply / exhaust flow path. Thus, since the direction of the hot air is switched in the heat treatment chamber, variation in the heat treatment state of the heated object depending on the hot air supply direction can be reduced, and a plurality of heated objects can be uniformly distributed regardless of the position in the heat treatment chamber. Can be heated. Further, the hot air generating / circulating part and the heat treatment chamber are connected to each other by a first air supply / exhaust flow channel and a second air supply / exhaust flow channel which are provided independently from the heat treatment chamber. Therefore, the hot air supplied from the hot air generating / circulating portion passes through the independent supply / exhaust flow path and is supplied to the heat treatment chamber without leaking to the exhaust side. Further, according to the configuration of the heating furnace according to the present invention, the hot air circulation direction is switched only in the heat treatment chamber, the first air supply / exhaust flow channel, and the second air supply / exhaust flow channel on the downstream side of the air direction switching valve. In the generation circulation part, the circulation direction can always be constant. For example, in the case where a plurality of heat supply sources and supply / exhaust paths are provided according to the configuration in which the air direction is changed or the circulation direction in the blowing unit, the configuration becomes complicated. However, in the heating furnace of the present invention, since the hot air is always circulated in a constant direction in the hot air generating and circulating section, and the object to be heated can be heated uniformly only by switching the air direction switching valve, the structure is complicated. Can be suppressed. Also, for example, there are two exhaust passages from which the exhaust hot air from the wind direction switching valve reaches the heat supply source again, and when the exhaust hot air passes through one exhaust passage, the other exhaust passage When the exhaust hot air does not pass, the other exhaust passage through which the exhaust hot air does not pass loses heat and the temperature decreases. When the circulation direction is switched in this state and the exhaust hot air is passed through the other exhaust passage, heat loss occurs in the exhaust passage whose temperature has decreased. On the other hand, in the present invention, the hot air generating and circulating section can always circulate hot air in the same state, and the same exhaust passage can be used in the first state and the second state. Loss can be suppressed. As described above, the object to be heated can be uniformly heated regardless of the position in the heat treatment chamber without complicating the configuration and suppressing heat loss.

  In the heating furnace according to the present invention, the heat treatment chamber has a plurality of stages of heat treatment spaces formed by being partitioned by a horizontal partition wall, and the hot air from the hot air generating and circulating part is branched and passed through the heat treatment spaces of the respective stages. In addition, a curved first heat loss adjusting plate that protrudes longer toward the first air supply / exhaust flow path as the distance from the heat supply source is larger is disposed at the connection with the first air supply / exhaust flow path in the heat treatment space of each stage. The second heat loss adjusting plate having a curved shape that protrudes longer toward the second air supply / exhaust flow path as the distance from the heat supply source is larger at the connection portion with the second air supply / exhaust flow path in the heat treatment space of each stage. It is preferable that the first heat loss adjusting plate and the second heat loss adjusting plate are arranged symmetrically via the heat treatment chamber. By providing the curved heat loss adjusting plate, the supplied hot air can be uniformly supplied to the heat treatment space of each stage. Since the heat loss adjusting plate protrudes longer as the distance from the heat supply source is larger, the supplied hot air can be supplied uniformly regardless of the position of the heat treatment space. In addition, since the first heat loss adjustment plate and the second heat loss adjustment plate are arranged symmetrically via the heat treatment chamber, the supply air hot air supply state is changed even if the first state and the second state are switched. It can be made the same on the one supply / exhaust flow path side and the second supply / exhaust flow path side.

  In the heating furnace according to the present invention, the wind direction switching valve includes a single switching plate, and the switching plate applies the hot air from the supply air flow path of the hot air generation circulation section to one surface to thereby apply the first supply / exhaust flow path. And the second air supply / exhaust flow path, and the hot air exhausted from the other of the first air supply / exhaust flow path and the second air supply / exhaust flow path is applied to the other surface, so that It is preferable to guide to the road. When exhaust hot air hits the other surface of the switching plate, the temperature drop on the other surface is suppressed. Therefore, the heat loss of the supply hot air when hitting the switching plate can be suppressed.

  In the heating furnace according to the present invention, the length of the first air supply / exhaust flow path and the length of the second air supply / exhaust flow path are preferably the same. Thereby, even if the first state and the second state are switched, the flow path lengths on the air supply side and the exhaust side can be made unchanged, so the supply state of the supply air hot air is changed to the first air supply / exhaust flow path side. It can be made the same on the second air supply / exhaust flow path side.

  According to the present invention, the object to be heated can be uniformly heated regardless of the position in the heat treatment chamber without complicating the configuration and suppressing heat loss.

It is a front view showing a schematic structure of a heating furnace concerning an embodiment of the present invention. It is sectional drawing along the II-II line | wire shown in FIG. It is the schematic block diagram which looked at the hot air generation | occurrence | production circulation part shown in FIG. 1 from the side.

  Hereinafter, preferred embodiments of a heating furnace according to the present invention will be described in detail with reference to the drawings. A heating furnace 1 shown in FIGS. 1, 2 and 3 is used as a degreasing furnace for performing a degreasing process by heating a ceramic molded body before a firing process in a manufacturing process of a ceramic electronic component. FIG. 1 is a front view showing a schematic configuration of a heating furnace 1 according to an embodiment of the present invention. In FIG. 1, the heat treatment chamber and its peripheral part are shown in cross section. FIG. 2 is a cross-sectional view taken along the line II-II shown in FIG. FIG. 3 is a schematic configuration diagram of the hot air generating and circulating unit shown in FIG. 1 as viewed from the side.

  The heating furnace 1 includes a heat treatment chamber 10 that is surrounded by a heat insulating wall and accommodates an object to be heated W of a ceramic molded body, a hot air generation circulation unit 20 that generates hot air and supplies and exhausts the heat treatment chamber 10, and a heat treatment chamber 10 A first air supply / exhaust flow path 30 connecting the hot air generating / circulating part 20, a second air supply / exhaust flow path 40 connecting the heat treatment chamber 10 and the hot air generating / circulating part 20, and a wind direction for switching the hot air supply / exhaust circulation state. And a switching valve 60. In the heat treatment chamber 10, hot air from the hot air generation / circulation unit 20 blows out from either one, and the article to be heated W in the heat treatment chamber 10 is heated and degreased by being exposed to the hot air. By this degreasing treatment, the resin component (binder) in the ceramic molded body is removed prior to the firing treatment. The heating furnace 1 according to the present embodiment can be switched between the first state and the second state by switching the hot air supply direction to the heat treatment chamber 10 by the air direction switching valve 60. FIGS. 1A and 2A show the heating furnace 1 according to the first state, and FIGS. 1B and 2B show the heating furnace 1 according to the second state. As shown in FIG. 1, the heating furnace 1 has a symmetrical configuration when viewed from the front.

  The heat treatment chamber 10 is partitioned by a plurality of horizontal partition walls 11, and in the heat treatment chamber 10, multiple stages (here, five stages) of heat treatment spaces 13 a to 13 e overlapping in the vertical direction are formed. Yes. The partition wall 11 is a plate made of stainless steel, and the object to be heated W can be placed on the upper surface. In this way, by allowing the heated object W to be stored in the respective heat treatment spaces 13a to 13e, the heated object W can be efficiently stored in the heat treatment chamber 10, and the processing efficiency in the heating furnace 1 can be improved. It is illustrated. Both ends of the heat treatment chamber 10 are open, and the supply hot air PW is supplied from one of the openings, the supply hot air PW is passed through the heat treatment spaces 13a to 13e, and the exhaust hot air EW is supplied from the other opening. Exhaust. A more detailed configuration of the heat treatment chamber 10 will be described later.

  As shown in FIG. 3, the hot air generating and circulating unit 20 includes an air supply passage 21 through which the supply hot air PW to the heat treatment chamber 10 passes, an exhaust passage 22 through which the exhaust hot air EW from the heat treatment chamber 10 passes, A heat supply source 23 disposed between the air flow path 21 and the exhaust flow path 22 and a blower (blower unit) 24 that generates an air flow in the heating furnace 1 are provided.

  The hot air generating / circulating unit 20 includes an upper flow path 20A, a vertical flow path 20B, a lower flow path 20C, a connection flow path 20D, and a connection flow path 20E. The upper flow path 20A, the vertical flow path 20B, the lower flow path 20C, the connection flow path 20D, and the connection flow path 20E communicate with each other, and the first supply / exhaust flow path 30, the second supply / exhaust flow It is constituted by a pipe independent from the path 40 and the heat treatment chamber 10. The upper flow path 20 </ b> A extends in the direction perpendicular to the first air supply / exhaust flow path 30 and the second air supply / exhaust flow path 40 above the wind direction switching valve 60 (here, the air direction switching valve 60 extends toward the rear side. ). The vertical channel 20B extends downward from the rear end of the upper channel 20A. The lower flow path 20C is located below the wind direction switching valve 60 in a direction orthogonal to the first air supply / exhaust flow path 30 and the second air supply / exhaust flow path 40 from the lower end of the vertical flow path 20B (here, to the wind direction switching valve 60). Toward the front side). The lower flow path 20 </ b> C extends at a height position between the air direction switching valve 60 and the heat treatment chamber 10. The connection flow path 20D extends upward from the lower flow path 20C and connects the lower flow path 20C and the air direction switching valve 60. The connection flow path 20E extends downward from the upper flow path 20A and connects the upper flow path 20A and the wind direction switching valve 60. The airtightness at the connection portion between the connection flow path 20D and the lower part of the wind direction switching valve 60 and the airtightness at the connection portion between the connection flow path 20E and the upper portion of the wind direction switching valve 60 are sufficiently secured. Therefore, the airtightness between the wind direction switching valve 60 and the hot air generating / circulating unit 20 is ensured. As described above, the hot air generation / circulation unit 20 is configured by a pipe that circulates independently from the first supply / exhaust flow path 30, the second supply / exhaust flow path 40, and the heat treatment chamber 10, and is connected to the wind direction switching valve 60. Since the airtightness of the portion is sufficiently ensured, the generated supply air hot air PW can be supplied to the wind direction switching valve 60 without leakage.

  A heat supply source 23 is disposed at a corner between the upper flow path 20A and the vertical flow path 20B. As shown in FIG. 3, the heat supply source 23 may be provided with a heater 23a outside the circulation channel and supply heat into the circulation channel via a pipe 23b. At this time, the heat supply source 23 can function as a blowing means by forming a circulation flow in the system by supplying hot air. Alternatively, a heater may be arranged directly in the circulation channel, heat may be generated in the circulation channel, and a blower 24 as shown in FIG. 3 may be arranged to generate hot air. The blower 24 is disposed on the front end side of the upper flow path 20A and blows downward toward the wind direction switching valve 60 via the connection flow path 20E (in the case of circulating only by the heat supply source 23 outside the circulation flow path). May omit the blower 24). An exhaust pipe 25 for exhausting a part of the hot exhaust air EW to the outside of the circulation flow path is disposed at a corner between the lower flow path 20C and the vertical flow path 20B.

  With such a configuration, the upstream flow path between the heat supply source 23 and the wind direction switching valve 60, that is, the upper flow path 20 </ b> A and the connection flow path 20 </ b> E function as the air supply flow path 21. On the other hand, the downstream flow path between the heat supply source 23 and the wind direction switching valve 60, that is, the connection flow path 20 </ b> D, the lower flow path 20 </ b> C, and the vertical flow path 20 </ b> B functions as the exhaust flow path 22. The supply hot air PW flows through the upper flow path 20 </ b> A and the connection flow path 20 </ b> E by air blown by the heat supply source 23 or the blower 24, and is supplied to the heat treatment chamber 10 via the wind direction switching valve 60. Further, the exhaust hot air EW is exhausted from the heat treatment chamber 10 through the air direction switching valve 60, flows through the connection flow path 20 </ b> D and the lower flow path 20 </ b> C, and is partially exhausted through the exhaust pipe 25. Further, the exhaust hot air EW flows through the vertical flow path 20B and is supplied with heat by the heat supply source 23, so that it again circulates in the circulation flow path as the supply hot air PW. The circulation direction in the hot air generation / circulation unit 20 is always the same regardless of the switching state in the wind direction switching valve 60.

  The arrangement of the heat supply source 23 is not limited to the position shown in FIG. 3 and may be arranged at any position in the flow paths 20A to 20E. In that case, the upstream flow path between the heat supply source 23 and the wind direction switching valve 60 functions as the air supply flow path 21, and the downstream flow path between the heat supply source 23 and the wind direction switching valve 60 is It functions as the exhaust passage 22. When the blower 24 is disposed as a blowing means, the blower 24 may be disposed at any position in the air supply passage 21 and the exhaust passage 22 and at a position where a flow of hot air can be created in the circulation passage. If there is, it will not be specifically limited. The exhaust pipe 25 may be disposed at any position as long as it is the exhaust flow path 22 or may not be provided.

  As shown in FIGS. 1 and 2, the first air supply / exhaust flow path 30 is configured by a single pipe independent from the hot air generating / circulating unit 20, the heat treatment chamber 10, and the second air supply / exhaust flow path 40. The first air supply / exhaust flow path 30 connects the hot air generating / circulating part 20 and the heat treatment chamber 10 via the air direction switching valve 60 on one side (the right side in the drawing) of the heating furnace 1. Specifically, the upper end of the first air supply / exhaust flow path 30 is connected to one side of the wind direction switching valve 60, and the lower end of the first air supply / exhaust flow path 30 is connected to the heat treatment chamber 10. It is connected to one side of the. The first air supply / exhaust flow path 30 extends horizontally from one side of the air direction switching valve 60 and bends vertically downward, the side wall at the lower end opens, and the opening is formed in one opening of the heat treatment chamber. Connected. The airtightness at the connection portion between the first air supply / exhaust flow path 30 and the air direction switching valve 60 and the airtightness at the connection portion between the first air supply / exhaust flow path 30 and the heat treatment chamber 10 are sufficiently secured. As described above, the first air supply / exhaust flow path 30 is a pipe independent of the hot air generation / circulation unit 20, the heat treatment chamber 10 and the second air supply / exhaust flow path 40, and is connected to the wind direction switching valve 60 and the heat treatment chamber 10. Therefore, the air supply hot air PW from the hot air generation / circulation unit 20 can be supplied to the heat treatment chamber 10 without leakage.

  The second air supply / exhaust flow path 40 is constituted by a single pipe independent from the hot air generating / circulating unit 20, the heat treatment chamber 10, and the first air supply / exhaust flow path 30. The second air supply / exhaust flow path 40 connects the hot air generating / circulating part 20 and the heat treatment chamber 10 via the air direction switching valve 60 on the other side (left side of the drawing) of the heating furnace 1. Specifically, the upper end of the second air supply / exhaust flow path 40 is connected to the other side of the wind direction switching valve 60, and the lower end of the second air supply / exhaust flow path 40 is connected to the heat treatment chamber 10. It is connected with the other side part. The second air supply / exhaust flow path 40 extends horizontally from the other side portion of the air direction switching valve 60 and bends vertically downward. The side wall at the lower end portion opens, and the opening portion is formed in the other opening portion of the heat treatment chamber. Connected. The airtightness at the connection portion between the second air supply / exhaust flow path 40 and the air direction switching valve 60 and the airtightness at the connection portion between the second air supply / exhaust flow path 40 and the heat treatment chamber 10 are sufficiently secured. As described above, the second air supply / exhaust flow path 40 is a pipe independent from the hot air generation / circulation unit 20, the heat treatment chamber 10 and the first air supply / exhaust flow path 30, and is connected to the wind direction switching valve 60 and the heat treatment chamber 10. Therefore, the air supply hot air PW from the hot air generation / circulation unit 20 can be supplied to the heat treatment chamber 10 without leakage.

  The first air supply / exhaust flow path 30 and the second air supply / exhaust flow path 40 are symmetric with respect to the air direction switching valve 60 and the heat treatment chamber 10. Therefore, the length of the first air supply / exhaust flow path 30 is the same as the length of the second air supply / exhaust flow path 40. Moreover, the cross-sectional shape and flow path area in the corresponding location of the 1st air supply / exhaust flow path 30 and the 2nd air supply / exhaust flow path 40 are also the same. As shown in FIGS. 1A and 2A, in the first state, the first air supply / exhaust flow path 30 is on the air supply side, and the second air supply / exhaust flow path 40 is on the exhaust side. That is, the supply hot air PW from the hot air generation / circulation unit 20 passes through the first supply / exhaust flow path 30, and the exhaust hot air EW from the heat treatment chamber 10 passes through the second supply / exhaust flow path 40. As shown in FIGS. 1B and 2B, in the second state, the second air supply / exhaust flow path 40 is on the air supply side, and the first air supply / exhaust flow path 30 is on the exhaust side. That is, the supply hot air PW from the hot air generation / circulation unit 20 passes through the second supply / exhaust flow path 40, and the exhaust hot air EW from the heat treatment chamber 10 passes through the first supply / exhaust flow path 30.

  As shown in FIGS. 1 and 3, the wind direction switching valve includes a switching plate 61 that switches the direction of hot air, a rotating shaft 62 of the switching plate 61, and a cylindrical cylinder 63 that forms the outer wall of the valve. ing. The outer peripheral wall of the cylinder 63 communicates with the connection flow path 20E of the hot air generation / circulation section 20 on the upper side, and communicates with the connection flow path 20D of the hot air generation / circulation section 20 on the lower side. ) Communicates with the first air supply / exhaust flow path 30 and communicates with the second air supply / exhaust flow path 40 on the other side in the horizontal direction (left side in FIG. 1). The rotation shaft 62 is disposed on the axis of the cylinder 63 in the cylinder 63. The switching plate 61 is a single plate member arranged to divide the internal space of the cylinder 63 into two spaces in the circumferential direction. Here, “one sheet” means that a single switching plate is formed by superimposing or connecting a plurality of plates even when the entire switching plate 61 is formed as a single plate. The case of 61 is also included. The switching plate 61 is pivotally supported by a rotation shaft 62 at the center position, and is switched to a position corresponding to the first state of the heating furnace 1 and a position corresponding to the second state. The outer edge portion of the switching plate 61 is disposed without a gap from the inner surface of the cylinder 63, and airtightness is ensured. The wind direction switching valve 60 is electrically connected to a control device (not shown), and the control device switches the first state and the second state at a predetermined time interval. It is preferable to control the time of the first state and the time of the second state to be equal so that the article W to be heated in the heat treatment chamber 10 is uniformly heat-treated regardless of the place. Specifically, while the total time of heat treatment in the heat treatment chamber 10 is 10 hours to 60 hours, the state is preferably switched at a time interval of 10 minutes to 60 minutes.

  As shown in FIG. 1 (a), in the first state, the switching plate 61 is inclined so that the other end portion faces upward, and the other end portion is connected to the connection flow path 20E of the hot air generating / circulating portion 20 and the second flow path. It arrange | positions between the two air supply / exhaust flow paths 40, and will be in the state arrange | positioned between the connection flow path 20D of the hot air generation circulation part 20 and the 1st air supply / exhaust flow path 30 between downward. As a result, the connection flow path 20 </ b> E constituting the air supply flow path 21 is communicated with the first air supply / exhaust flow path 30 and is blocked from the second air supply / exhaust flow path 40. Further, the connection flow path 20 </ b> D constituting the exhaust flow path 22 is communicated with the second supply / exhaust flow path 40 and is blocked from the first supply / exhaust flow path 30. The switching plate 61 guides to the first air supply / exhaust flow path 30 by applying the hot air PW from the connection flow path 20E related to the air supply flow path 21 to the first surface 61a. Further, the switching plate 61 guides the exhaust hot air EW exhausted from the second air supply / exhaust flow path 40 to the second flow path 61b to the connection flow path 20D related to the exhaust flow path 22. The exhaust hot air EW hits the second surface 61b, so that the switching plate 61 can be kept at a high temperature without lowering the temperature. With such a configuration, it is suppressed that heat is taken away when the supply hot air PW hits the first surface 61a. Since airtightness between the cylinder 63 and the switching plate 61 is ensured, the supply hot air PW leaks to the exhaust flow path 22 side, and the exhaust hot air EW leaks to the first supply / exhaust flow path 30 side. Is prevented.

  As shown in FIG. 1B, in the second state, the switching plate 61 is inclined so that one end thereof faces upward, and the one end is connected to the connection flow path 20E of the hot air generating and circulating unit 20 and the first supply. It arrange | positions between the exhaust flow paths 30, and it will be in the state arrange | positioned between the connection flow path 20D of the hot air generation | occurrence | production circulation part 20 and the 2nd air supply / exhaust flow path 40 between downward. As a result, the connection flow path 20 </ b> E constituting the air supply flow path 21 is communicated with the second air supply / exhaust flow path 40 and is blocked from the first air supply / exhaust flow path 30. Further, the connection flow path 20 </ b> D constituting the exhaust flow path 22 communicates with the first supply / exhaust flow path 30 and is blocked from the second supply / exhaust flow path 40. The switching plate 61 guides to the second air supply / exhaust flow path 40 by applying the hot air PW from the connection flow path 20E related to the air supply flow path 21 to the second surface 61b. Further, the switching plate 61 guides the exhaust hot air EW exhausted from the first air supply / exhaust flow path 30 to the first flow path 61 a to the connection flow path 20 </ b> D related to the exhaust flow path 22. The exhaust hot air EW hits the first surface 61a, so that the switching plate 61 can be kept at a high temperature without lowering the temperature. With such a configuration, it is possible to prevent heat from being taken away when the supply hot air PW hits the second surface 61b. Since the airtightness between the cylinder 63 and the switching plate 61 is ensured, the supply hot air PW leaks to the exhaust flow path 22 side and the exhaust hot air EW leaks to the second supply / exhaust flow path 40 side. Is prevented.

  Generally, a resin component is contained in the article to be heated W of the ceramic molded body, and in the heating furnace 1, the resin component in the article to be heated W is gradually removed over a long period of time. The removal rate of the resin component depends on the temperature, the air volume, and the resin concentration in the atmosphere gas of the atmosphere gas that contacts the object to be heated W as hot air. Here, when there are variations in the temperature of the atmosphere gas, the air volume, and the resin concentration for each position in the heat treatment chamber 10, the resin removal speed is increased for each object to be heated W arranged in each position in the heat treatment chamber 10. It will vary. For example, when the removal rate of the resin is too fast, there is a possibility that cracks may occur in the article to be heated W. In addition, when the resin removal rate is too slow, the resin component remains in the article to be heated W even after the processing is completed. Therefore, in order to perform uniform degreasing without unevenness on all the objects to be heated W in the heat treatment chamber 10, it is necessary to reduce variations in the temperature distribution, the air volume distribution, and the resin concentration distribution in the heat treatment chamber 10.

  Therefore, the heating furnace 1 includes stainless heat loss adjusting plates A51a to A51e and B51a to B51e respectively corresponding to the five stages of heat treatment spaces 13a to 13e. Among these, 1st heat loss adjustment board A51b-A51e is provided in the connection part 31 with the 1st air supply / exhaust flow path 30 in each heat processing space 13b-13e, respectively. The first heat loss adjustment plates A51b to A51e are fixed to the end portions of the partition wall 11 forming the upper wall that partitions the heat treatment spaces 13b to 13e, and the first heat loss adjustment plates A51b to A51e are respectively The first supply / exhaust flow path 30 extends so as to protrude. And 1st heat loss adjustment board A51b-A51e is curving so that a front-end | tip may face upwards. With such a curved shape, each of the first heat loss adjusting plates A51b to A51e guides the hot air PW in the vertical direction from the first air supply / exhaust flow path 30 in the first state to generate hot air in the horizontal direction ( 1 (a)), hot air is smoothly introduced into each of the heat treatment spaces 13b to 13e. The first heat loss adjustment plate A51a is fixed to the lower wall surface of the heat treatment chamber 10, but the supply hot air PW is supplied to the heat treatment space 13a with the same configuration as the other first heat loss adjustment plates A51b to A51e. Introduce smoothly.

  The length of the first heat loss adjusting plates A51a to A51e protruding toward the first air supply / exhaust flow path 30 is longer in the order of the first heat loss adjusting plates A51e, A51d, A51c, A51b, A51a. That is, the lengths of the heat loss adjustment plates A51a to A51e are longer as they are positioned below. In other words, as the distance from the heat supply source 23 increases, the first heat loss adjustment plates A51a to A51e. A51e is longer. The widths and thicknesses of the first heat loss adjustment plates A51a to A51e are all the same.

  The second heat loss adjustment plates B51a to B51e have a symmetrical configuration with the first heat loss adjustment plates A51a to A51e via the heat treatment chamber 10. The second heat loss adjusting plates B51b to B51e are provided at the connection portions 41 with the second air supply / exhaust flow paths 40 in the corresponding heat treatment spaces 13b to 13e, respectively. The second heat loss adjustment plates B51b to B51e are fixed to the end portions of the partition wall 11 forming the upper wall that partitions the heat treatment spaces 13b to 13e, and the second heat loss adjustment plates B51b to B51e are respectively The second air supply / exhaust flow path 40 extends so as to protrude. And 2nd heat loss adjustment board B51b-B51e is curving so that a front-end | tip may face upwards. With such a curved shape, each of the second heat loss adjustment plates B51b to B51e guides the vertical supply air hot air PW from the second air supply / exhaust flow path 40 in the second state to generate horizontal hot air ( 1 (b)), hot air is smoothly introduced into each of the heat treatment spaces 13b to 13e. The second heat loss adjustment plate B51a is fixed to the lower wall surface of the heat treatment chamber 10, but the supply hot air PW is supplied to the heat treatment space 13a with the same configuration as the other second heat loss adjustment plates B51b to B51e. Introduce smoothly.

  The length of the second heat loss adjustment plates B51a to B51e protruding toward the second air supply / exhaust flow path 40 is longer in the order of the second heat loss adjustment plates B51e, B51d, B51c, B51b, and B51a. That is, the lengths of the heat loss adjustment plates B51a to B51e are longer as they are positioned below. In other words, the longer the distance from the heat supply source 23, the greater the second heat loss adjustment plates B51a to B51a. B51e is longer. The widths and thicknesses of the second heat loss adjustment plates B51a to B51e are all the same.

  Further, in each of the heat treatment spaces 13a to 13e, two mesh members arranged in a double layer so as to close the openings on both sides of the heat treatment chamber 10 are provided. Among these, the outer mesh material with respect to the heat treatment chamber 10 is a first mesh material 53, and the inner mesh material is a second mesh material 55. The first mesh material 53 and the second mesh material 55 are located between the placement position of the article to be heated W and the first heat loss adjusting plates A51a to A51e, and the placement position of the article to be heated W and the second heat loss. It is located between the adjustment plates B51a to B51e. The first mesh material 53 and the second mesh material 55 are stainless steel wire mesh members having a predetermined opening ratio (about 60%), and supply air hot air PW introduced into the heat treatment spaces 13a to 13e. Passes through the first mesh material 53 and the second mesh material 55 in order. The first mesh material 53 and the second mesh material 55 at each stage are all arranged at the same position as viewed from above. However, the second mesh material 55 at each stage may be arranged so as to gradually shift inward as it goes upward. The second mesh material 55 at each stage can be adjusted in the front-rear direction by a configuration that is detachably attached to the partition wall 11 by, for example, screwing. The opening ratios of the first and second mesh members 53 and 55 in each step are adjusted for each step and are different from each other. The mesh materials 53 and 55 on the first air supply / exhaust flow path 30 side and the mesh materials 53 and 55 on the second air supply / exhaust flow path 40 side are configured symmetrically via the heat treatment chamber 10.

  Thus, since the first mesh material 53 of each step is disposed at the same position when viewed from above, hot air is introduced into each of the heat treatment spaces 13a to 13e under substantially the same conditions to adjust the position of the second mesh material 55. By doing so, even if the radiant heat from each of the heat treatment spaces 13a to 13e varies, the influence on the second mesh material 55 can be made common in the heat treatment spaces 13a to 13e of each stage. Moreover, the aperture ratios of the mesh materials 53 and 55 at each step are adjusted for each step and are different from each other. Thus, by adjusting the aperture ratio of the mesh materials 53 and 55 for each step, the temperature distribution for each heat treatment space 13a to 13e of each step can be adjusted more precisely.

  Further, in each of the heat treatment spaces 13a to 13e, a plurality of (here, six) stainless steel heat distribution adjusting plates are provided in the space between the first mesh material 53 and the second mesh material 55 on both sides. 57 is provided. The heat distribution adjusting plate 57 is provided on the upper surface of the partition wall 11 (or the bottom wall surface of the heat treatment chamber 10), and is arranged horizontally in the depth direction in FIG. The heat distribution adjusting plate 57 is slightly inclined when viewed from above, thereby affecting the flow of hot air at the installation position of the article to be heated W. That is, the heat distribution adjusting plate 57 is inclined so as to guide the hot air PW near the center to the outside as viewed from above. With this configuration, in each of the heat treatment spaces 13a to 13e, variation in the air volume in a plane orthogonal to the hot air is reduced. The heat distribution adjusting plate 57 on the first air supply / exhaust flow path 30 side and the heat distribution adjusting plate 57 on the second air supply / exhaust flow path 40 side are configured symmetrically via the heat treatment chamber 10.

  The first mesh material 53 disperses the distribution of hot air passing therethrough, thereby making the temperature distribution equal. Further, since the horizontal temperature variation remaining after passing through the first mesh material 53 is compensated by the heat distribution adjusting plate 57 functioning as a heat storage material, the horizontal temperature distribution in the heat treatment spaces 13a to 13e is made uniform. Is done. Further, the second mesh material 55 suppresses the direct influence of the radiant heat from the heat treatment spaces 13 a to 13 e on the heat distribution adjusting plate 57, and disperses the radiant heat within the surface of the second mesh material 55. Thereby, the temperature of the heat distribution adjusting plate 57 is stabilized without suddenly changing, and the temperature distribution of the cross section perpendicular to the flow in the hot air that has passed through the second mesh material 55 is made uniform.

  The heat loss adjusting plates A51a to A51e, B51a to B51e, the mesh materials 53 and 55, and the heat distribution adjusting plate 57 are made of stainless steel. As described above, the heat loss adjusting plates A51a to A51e and B51a to B51e as the heat distribution compensating members, the mesh materials 53 and 55, and the heat distribution adjusting plate 57 are made of stainless steel having high heat retention (poor heat conduction). With this configuration, even if a disturbance occurs, these heat distribution compensation members do not rapidly change in temperature, and it is easy to maintain a constant temperature distribution in the heat treatment chamber 10.

  The heat treatment chamber 10 includes a heated object storage magazine 12 that can be inserted into and removed from the furnace body. This heated article storage magazine 12 is separate from the portion where the heat loss adjusting plates A51a to A51e, B51a to B51e, the mesh materials 53 and 55, and the heat distribution adjusting plate 57 are fixed to the furnace body side. Thus, only the region where the article to be heated W is placed can be removed. Moreover, the airtightness between the furnace body and the article to be heated storage 12 is ensured, and the supplied hot air PW can be supplied to the heat treatment spaces 13a to 13e without leaking to other heat treatment spaces. With such a configuration, it becomes easy to put the workpiece W into and out of the heat treatment chamber 10.

  Then, the effect of the heating furnace 1 based on the above-mentioned structure is demonstrated.

  In the first state, as shown in FIGS. 1 (a), 2 (a), and FIG. 3, the supply hot air PW is supplied to the upper side of the supply air flow path 21 by the heat supply and the ventilation from the heat supply source 23. It flows through the flow path 20A and the connection flow path 20E and hits the first surface 61a of the switching plate 61 of the air direction switching valve 60. The supply hot air PW guided by the first surface 61a passes through the first air supply / exhaust flow path 30, and is guided by the first heat loss adjustment plates A51a to A51e while being heat-treated spaces 13a to 13e at the respective stages of the heat treatment chamber 10. It branches into and flows in. Thereafter, the exhaust hot air EW exhausted from the heat treatment chamber 10 joins again while being guided by the second heat loss adjusting plates B51a to B51e and passes through the second air supply / exhaust flow path 40. The exhaust hot air EW hits the second surface 61 b of the switching plate 61 of the air direction switching valve 60 and is guided to the exhaust flow path 22 of the hot air generating and circulating unit 20. The exhaust hot air EW flows through the connection flow path 20D and the lower flow path 20C and is partially exhausted through the exhaust pipe 25. Further, the exhaust hot air EW flows through the vertical flow path 20B and is supplied with heat by the heat supply source 23, so that it again circulates in the heating furnace 1 as the supply air hot air PW.

  In the second state, as shown in FIGS. 1 (b), 2 (b), and 3, the supply hot air PW is supplied to the upper side of the supply flow passage 21 by the heat supply and the air blowing from the heat supply source 23. It flows through the flow path 20A and the connection flow path 20E and hits the second surface 61b of the switching plate 61 of the air direction switching valve 60. The supply hot air PW guided by the second surface 61b passes through the second supply / exhaust flow path 40 and is guided by the second heat loss adjusting plates B51a to B51e while being heat-treated spaces 13a to 13e at the respective stages of the heat treatment chamber 10. It branches into and flows in. Thereafter, the exhaust hot air EW exhausted from the heat treatment chamber 10 joins again while being guided by the first heat loss adjusting plates A51a to A51e and passes through the first air supply / exhaust flow path 30. The exhaust hot air EW hits the first surface 61 a of the switching plate 61 of the air direction switching valve 60 and is guided to the exhaust flow path 22 of the hot air generating and circulating unit 20. The exhaust hot air EW flows through the connection flow path 20D and the lower flow path 20C and is partially exhausted through the exhaust pipe 25. Further, the exhaust hot air EW flows through the vertical flow path 20B and is supplied with heat by the heat supply source 23, so that it again circulates in the heating furnace 1 as the supply air hot air PW. Such switching between the first state and the second state is performed at the same time interval.

  As described above, according to the heating furnace 1 according to the present embodiment, when the air direction switching valve 60 is switched to the first state, the supply hot air PW from the hot air generation / circulation unit 20 causes the first supply / exhaust flow in the heat treatment chamber 10. It passes from the path 30 toward the second air supply / exhaust flow path 40. When the air direction switching valve 60 is switched to the second state, the supply hot air PW from the hot air generation / circulation unit 20 is directed from the second supply / exhaust flow path 40 to the first supply / exhaust flow path 30 in the heat treatment chamber 10. pass. Thus, since the direction of the supply air hot air PW is switched in the heat treatment chamber 10, variation in the heat treatment state of the article to be heated W depending on the supply direction of the supply air hot air PW can be reduced, and the position in the heat treatment chamber 10 can be reduced. Regardless of this, a plurality of articles to be heated W can be heated uniformly. The hot air generating / circulating unit 20 and the heat treatment chamber 10 are connected to each other by a first air supply / exhaust flow channel 30 and a second air supply / exhaust flow channel 40 that are provided independently from the heat treatment chamber 10. Therefore, the supply hot air PW from the hot air generation / circulation unit 20 is supplied to the heat treatment chamber 10 through the independent supply / exhaust flow path without leaking to the exhaust side.

  Moreover, according to the structure of the heating furnace 1 which concerns on this embodiment, the circulation direction of hot air PW and EW is the heat processing chamber 10, the 1st air supply / exhaust flow path 30, and the 2nd air supply / exhaust downstream of the wind direction switching valve 60. The flow direction is switched only in the flow path 40, and the circulation direction can always be constant in the hot air generation circulation section 20. For example, in the case where a plurality of heat supply sources and supply / exhaust paths are provided according to the configuration in which the air direction is changed or the circulation direction in the blowing unit, the configuration becomes complicated. However, in the heating furnace 1 of the present embodiment, the hot air PW and EW are always circulated in a constant direction in the hot air generating and circulating unit 20, and the object to be heated W is uniformly heated only by switching the wind direction switching valve 60. Therefore, the complexity of the structure can be suppressed.

  Further, for example, when there are two exhaust passages from which the exhaust hot air EW from the wind direction switching valve reaches the heat supply source, and the exhaust hot air EW passes through one exhaust passage, the other exhaust passage When the exhaust hot air EW does not pass through the other exhaust passage, the other exhaust passage through which the exhaust hot air EW does not pass loses heat and the temperature decreases. If the circulation direction is switched in this state and the exhaust hot air EW is passed through the other exhaust passage, heat loss occurs in the exhaust passage whose temperature has decreased. On the other hand, in the heating furnace 1 according to the present embodiment, the hot air generating and circulating unit 20 can always circulate hot air PW and EW in the same state, and the same exhaust flow path 22 is used in the first state and the second state. Therefore, heat loss in the exhaust passage 22 can be suppressed. As described above, the object to be heated W can be uniformly heated regardless of the position in the heat treatment chamber without complicating the configuration and suppressing heat loss.

  Here, for example, as a comparative example of a heating furnace that changes the direction of hot air in the heat treatment chamber, a switching plate that has one large opening at the top of the heat treatment chamber and can switch the inclination direction at the position of the opening. Considering a heating furnace in which a hot air generation source is disposed outside the heat treatment chamber at a position facing the opening and the switching plate, and the heat treatment chamber and the entire hot air generation source are surrounded by wall surfaces. The hot air generating source generates hot air so that hot air is applied to the surface of the switching plate (the outer surface as viewed from the heat treatment chamber), and rotates the switching plate through the opening to switch the direction of the air in the heat treatment chamber. Specifically, when the switching plate tilts to one side (one end of the switching plate enters the heat treatment chamber and the other end tilts away from the heat treatment chamber), the supply hot air is guided to the surface of the switching plate and switched. Enter the heat treatment chamber from one end of the plate. The hot air that has entered enters the heat treatment chamber from one side to the other side to perform heat treatment, is guided by the back surface of the switching plate, and is discharged from the other end side of the switching plate to the outside of the heat treatment chamber. The exhaust hot air discharged from the heat treatment chamber moves while being guided by the wall surface on the other side of the heating furnace (the movement path at this time functions as the first exhaust flow path) and is returned to the hot air generation source again. . When the switching plate tilts to the other side (the other end of the switching plate enters the heat treatment chamber and one end tilts away from the heat treatment chamber), the supply air hot air is guided to the surface of the switching plate and the other end of the switching plate Enter the heat treatment chamber. The hot air that has entered enters the heat treatment chamber from the other side to the one side, performs heat treatment, is guided to the back surface of the switching plate, and is discharged from the one end side of the switching plate to the outside of the heat treatment chamber. The exhaust hot air discharged from the heat treatment chamber moves while being guided by the wall surface on one side of the heating furnace (the moving path at this time functions as a second exhaust flow path) and is returned to the hot air generation source again. .

  However, in the heating furnace according to the comparative example, when the supply hot air from the hot air generation source is applied to the surface of the switching plate, some of the hot air flows to other parts without being guided into the heat treatment chamber. The entire amount of hot air cannot be supplied to the heat treatment chamber. Furthermore, since it is necessary to secure a flow path for exhaust, it is not possible to eliminate the escape path of the supplied hot air by closing the hot air generating source and the switching plate with a pipe or the like and making an airtight connection. Therefore, heat loss occurs on the supply side. As described above, there are two exhaust flow paths depending on the direction of the exhaust hot air exhausted from the heat treatment chamber. When exhaust hot air is passing through one exhaust passage, the temperature of the other exhaust passage is lowered. Therefore, heat loss also occurs on the exhaust side. On the other hand, in the heating furnace 1 according to the present embodiment, the air supply flow path 21 of the hot air generation and circulation unit 20 and the air direction switching valve 60 can be connected in an airtight manner, and between the air direction switching valve 60 and the heat treatment chamber 10. In addition, the air supply and exhaust passages 30 and 40 can be connected in an airtight manner. Accordingly, it becomes possible to supply the entire amount of the supply air hot air PW to the heat treatment chamber 10, and heat loss on the supply side can be suppressed. Furthermore, the movement path of the exhaust hot air EW from the wind direction switching valve 60 to the heat supply source 23 can also be integrated into one exhaust flow path 22 of the hot air generation / circulation unit 20 regardless of the wind direction. Therefore, the temperature drop of the exhaust hot air EW is suppressed, and heat loss on the exhaust side can be suppressed.

  In the heating furnace 1 according to the present embodiment, the heat treatment chamber 10 includes a plurality of heat treatment spaces 13 a to 13 e that are partitioned and formed by horizontal partition walls 11, and supplies the supplied hot air PW from the hot air generation circulation unit 20. The heat treatment spaces 13a to 13e of each stage can be branched and passed. In addition, the connection portion 31 of each stage of the heat treatment spaces 13a to 13e with the first supply / exhaust flow path 30 has a curved shape that protrudes longer toward the first supply / exhaust flow path 30 as the distance from the heat supply source 23 increases. The first heat loss adjusting plates A51a to A51e are arranged, and the connection portion 41 with the second air supply / exhaust flow path 40 in each stage of the heat treatment spaces 13a to 13e has a second distance as the distance from the heat supply source 23 increases. Curved second heat loss adjustment plates B51a to B51e that protrude long on the air supply / exhaust flow path 40 side are arranged, and the first heat loss adjustment plates A51a to A51e and the second heat loss adjustment plates B51a to B51e are heat treatment chambers. Are arranged symmetrically.

  With such a configuration, each of the heat loss adjustment plates A51a to A51e and B51a to B51e functions as a heat storage material. It is set and heat capacity increases. Accordingly, the hot air in contact with the heat loss adjusting plates A51a to A51e and B51a to B51e having larger heat capacities is introduced into the heat treatment spaces 13a to 13e of the respective stages as the amount of heat loss of the hot air is larger. For example, the hot air introduced into the lowermost heat treatment space 13a has a large heat loss because the flow path length from the heat supply source 23 is long. The hot air comes into contact with the heat loss adjusting plates A51a and B51a having a large heat capacity, and the hot air is introduced into the heat treatment space 13a in a state where the temperature is compensated. As described above, the heat loss adjusting plates A51a to A51e and B51a to B51e having different lengths and different heat capacities for the respective stages make the temperature of the hot air introduced into the heat treatment spaces 13a to 13e of the respective stages uniform and perform the heat treatment. The temperature distribution for each of the spaces 13a to 13e is made uniform. In addition, since the first heat loss adjustment plates A51a to A51e and the second heat loss adjustment plates B51a to B51e are arranged symmetrically via the heat treatment chamber 10, even if the first state and the second state are switched, the supply is not performed. The supply state of the hot air PW can be made the same on the first supply / exhaust flow channel 30 side and the second supply / exhaust flow channel 40 side.

  In the heating furnace 1 according to the present embodiment, the air direction switching valve 60 includes a single switching plate 61, and the switching plate 61 receives the supply hot air PW from the supply air passage 21 of the hot air generation circulation unit 20 on the first surface. The exhaust air flow 22 of the hot air generating and circulating unit 20 is guided to either the first air supply / exhaust flow channel 30 or the second air supply / exhaust flow channel 40 by hitting 61a, and the hot exhaust air EW is applied to the second surface 61b. Can be guided to. By the exhaust hot air EW hitting the second surface 61b of the switching plate 61, the temperature drop in the second surface 61b is suppressed. Therefore, the heat loss of the supply hot air PW when it hits the switching plate 61 can be suppressed.

  In the heating furnace 1 according to the present embodiment, the length of the first air supply / exhaust flow path 30 and the length of the second air supply / exhaust flow path 40 are the same. Accordingly, even if the first state and the second state are switched, the flow path lengths on the air supply side and the exhaust side can be made unchanged, so the supply state of the supply air hot air PW is changed to the first air supply / exhaust flow path. It can be made the same on the 30 side and the second air supply / exhaust flow path 40 side.

  The present invention is not limited to the embodiment described above. For example, the pipe length, shape, and arrangement of the hot air generating / circulating part and the supply / exhaust flow paths 30 and 40 are not limited to those shown in the embodiment, and may be changed as appropriate. In addition, the positional relationship between the hot air generation / circulation unit 20 and the heat treatment chamber 10 may be changed as appropriate, and the hot air generation / circulation unit 20 may be disposed on the side of the heat treatment chamber 10 or on the lower side. Moreover, in the above-mentioned embodiment, although the heating furnace 1 was made into the left-right symmetric structure as a particularly preferable example, it does not need to be left-right symmetric. For example, the length and thickness of the first air supply / exhaust flow path 30 and the second air supply / exhaust flow path 40 may be different.

  DESCRIPTION OF SYMBOLS 1 ... Heating furnace, 10 ... Heat processing chamber, 20 ... Hot air generation circulation part, 21 ... Supply air flow path, 22 ... Exhaust flow path, 23 ... Heat supply source (heat supply source, blowing means), 24 ... Blower (blowing means) 30 ... 1st air supply / exhaust flow path, 40 ... 2nd air supply / exhaust flow path, A51a-A51e ... 1st heat loss adjustment plate, B51a-B51e ... 2nd heat loss adjustment plate, 60 ... Airflow direction switching valve, 61 ... Switching Plate, 61a ... first surface (one surface), 61b ... second surface (the other surface), W ... object to be heated.

Claims (4)

A heat treatment chamber for heat-treating an object to be heated;
A hot air generating and circulating unit for generating hot air and supplying and exhausting the heat treatment chamber;
A first air supply / exhaust flow path that is provided independently from the heat treatment chamber and is connected to one side of the heat treatment chamber and connects the heat treatment chamber and the hot air generation circulation section;
A second air supply / exhaust flow path that is provided independently from the heat treatment chamber and the first air supply / exhaust flow path, is connected to the other side of the heat treatment chamber, and connects the heat treatment chamber and the hot air generation circulation section;
The first air supply / exhaust flow path and the hot air generation / circulation part, and the second air supply / exhaust flow path and the hot air generation are disposed between the first air supply / exhaust flow path and the second air supply / exhaust flow path. A wind direction switching valve for connecting the circulation part,
The hot air generating and circulating part is
An air supply passage for passing hot air supplied to the heat treatment chamber;
An exhaust passage for passing hot air exhausted from the heat treatment chamber;
A heat supply source disposed between the air supply channel and the exhaust channel;
Air blowing means disposed at any position in the air supply flow path and the exhaust flow path,
The wind direction switching valve is
Arranged between the air supply flow path and the exhaust flow path of the hot air generating and circulating section,
A first state in which the first air supply / exhaust flow path is the air supply side and the second air supply / exhaust flow path is the exhaust side, and the first air supply / exhaust flow path is the exhaust side and the second air supply / exhaust flow A heating furnace characterized by switching between a second state in which the passage is on the supply side. The heat treatment chamber has a plurality of stages of heat treatment spaces formed by being partitioned by a horizontal partition wall, and the hot air from the hot air generation circulation section is branched and passed through the heat treatment spaces of the respective stages,
A curved first heat loss adjustment that protrudes longer toward the first air supply / exhaust flow path as the distance from the heat supply source is larger at a connection portion with the first air supply / exhaust flow path in the heat treatment space of each stage The board is placed,
A second heat loss adjustment having a curved shape that protrudes longer toward the second air supply / exhaust flow path as the distance from the heat supply source is larger at a connection portion with the second air supply / exhaust flow path in the heat treatment space of each stage The board is placed,
2. The heating furnace according to claim 1, wherein the first heat loss adjusting plate and the second heat loss adjusting plate are arranged symmetrically via the heat treatment chamber. The wind direction switching valve includes a single switching plate,
The switching plate guides one of the first air supply / exhaust flow path and the second air supply / exhaust flow path by applying hot air from the air supply flow path of the hot air generating and circulating part to one surface, The hot air exhausted from the other of the first air supply / exhaust flow channel and the second air supply / exhaust flow channel is applied to the other surface of the hot air generation / circulation unit so as to be guided to the exhaust flow channel. Or the heating furnace of 2. The length of said 1st air supply / exhaust flow path and the length of said 2nd air supply / exhaust flow path are the same, The heating furnace as described in any one of Claims 1-3 characterized by the above-mentioned.

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