JP2023049556A - Heat treatment device - Google Patents

Abstract

To provide a heat treatment device capable of suppressing leakage of an atmospheric gas from a boundary between adjacent muffles and the like in the plurally divided muffles.SOLUTION: A heat treatment device comprises: ceramic muffles 11 formed with heat treatment spaces S for heat-treating work-pieces W; and a metallic cover 30 covering the muffles 11. The muffles 11 are formed plurally divided, and the plurally divided muffles are arranged side by side so as to connect the heat treatment spaces S. The cover 30 comprises: plural main covers 31 covering a boundary K1 between neighboring muffles of the plurally divided muffles; and auxiliary covers 32 cross-linking the plural main covers 31.SELECTED DRAWING: Figure 3

Description

The present invention relates to a heat treatment apparatus.

Patent Document 1 discloses a heat treatment furnace equipped with a retort in which the outside of a ceramic tube is covered with a metal shell, and configured to heat-treat a workpiece while conveying it in the ceramic tube in the axial direction. In this heat treatment furnace, a ceramic tube is axially divided into a plurality of split bodies, and the plurality of split bodies are inserted into one metal shell.

JP 2015-83919 A

In the heat treatment furnace described in Patent Document 1, it is not easy to completely eliminate gaps at the boundaries between adjacent split bodies of the ceramic tube, and atmospheric gas may leak through these gaps or external gases may enter. have a nature. On the other hand, since the plurality of divided bodies are covered with metal shells, leakage of atmospheric gas through the gaps is suppressed to some extent. However, metal shells are more susceptible to thermal deformation than ceramic tubes. Furthermore, the metal shell consists of one long cylinder. Since the cylindrical body covers all of the plurality of divided bodies, it has a large volume. As the volume of the cylindrical body increases, the cylindrical body is more likely to warp due to heat. Therefore, the amount of thermal deformation of the metal shell increases. As a result, there is a risk that the metal shell will partially float from the ceramic tube, making it impossible to sufficiently close the gap.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a heat treatment apparatus capable of suppressing atmospheric gas leakage from boundaries between adjacent muffles in a muffle divided into a plurality of sections.

(1) The present invention comprises a ceramic muffle in which a heat treatment space for heat-treating a work is formed, and a metal cover covering the muffle, wherein the muffle is divided into a plurality of parts. , in a heat treatment apparatus in which a plurality of divided muffles are arranged so as to connect the heat treatment space,
the cover includes a main cover that covers a boundary between adjacent muffles in the muffle divided into a plurality of sections;
and a sub cover that bridges the plurality of main covers.

According to the above configuration, the divided muffle is covered with the main cover and the sub cover. That is, the cover is divided into a main cover and a sub cover, and the area per single cover is reduced. Therefore, compared with the case where the cover is not divided, deformation of the main cover and the sub cover due to heat can be suppressed. Therefore, it is possible to prevent the main cover from floating from the muffle, and to prevent atmospheric gas from leaking from the boundary to the outside of the muffle and external gas from entering the muffle. Also, the cover has a sub-cover that bridges the plurality of main covers. Therefore, the main cover is pressed from the outside by the sub cover. Thereby, the lifting of the main cover from the muffle is further suppressed.

(2) Preferably, at least one main cover covers a plurality of boundaries.
Such a configuration reduces the total number of covers compared to one main cover per boundary.

(3) Preferably, the heat treatment apparatus includes a holding mechanism that restricts relative movement between the main cover and the sub cover.
With such a configuration, it is possible to prevent the main cover and the sub cover from being superimposed.

Advantageous Effects of Invention According to the present invention, it is possible to suppress leakage of ambient gas from the boundary between adjacent muffles in a muffle divided into a plurality of sections.

1 is a schematic diagram of a heat treatment apparatus according to a first embodiment of the present invention; FIG. FIG. 2 is a cross-sectional view taken along line AA of FIG. 1; FIG. 3 is a cross-sectional view of the muffle and cover taken along line BB of FIG. 2; FIG. 4 is a schematic perspective view showing a muffle and cover; (a) is a cross-sectional view of the cover in the C part of FIG. 3, and (b) is a D arrow view of (a). FIG. 4 is a cross-sectional view of the cover in the E section of FIG. 3; FIG. 3 is a cross-sectional view of the muffle and the cover in section F of FIG. 2; FIG. 5 is a cross-sectional view showing a cover in a second embodiment of the invention; FIG. 11 is a cross-sectional view showing a holding mechanism according to a third embodiment of the invention;

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a schematic diagram of a heat treatment apparatus according to one embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line AA of FIG. 3 is a cross-sectional view of the muffle along line BB of FIG. 2. FIG.
The heat treatment apparatus of this embodiment is a continuous heat treatment furnace 10 . The continuous heat treatment furnace 10 performs heat treatment while sequentially transporting a plurality of works W. As shown in FIG. In the following description, the direction in which the work W is conveyed is denoted by X, the width direction of the muffle 11 perpendicular to the direction X in which the work W is conveyed is denoted by Y, and the vertical direction perpendicular to the directions X and Y is denoted by Z. indicated by .

The continuous heat treatment furnace 10 has a muffle 11, a conveying device 12, a heat insulating wall 13, a heating device 14, a gas supply pipe 15, a cover 30 and the like.
The muffle 11 is formed in a cylindrical shape and has a heat treatment space S inside. The muffle 11 is formed long in the direction X in which the workpiece W is conveyed, and the heat treatment space S also extends in the same direction X. As shown in FIG. Therefore, the work W is conveyed in the longitudinal direction of the muffle 11 . In the following description, the longitudinal direction of the muffle 11 may also be denoted by X. As shown in FIG.

The muffle 11 has a bottom portion 21 , a pair of side wall portions 22 and a ceiling portion 23 . A space surrounded by the bottom portion 21, the side wall portion 22, and the ceiling portion 23 serves as a heat treatment space S. As shown in FIG.

A bottom portion 21 of the muffle 11 has a flat upper surface 21a. The pair of side wall portions 22 linearly extends upward from both ends of the bottom portion 21 in the width direction Y of the muffle 11 . The ceiling portion 23 is provided so as to straddle the upper end portions of the pair of side wall portions 22 .

In the muffle 11 of this embodiment, the side wall portion 22 and the ceiling portion 23 are integrated, and these and the bottom portion 21 are separately configured. Lower ends of the pair of side wall portions 22 are in contact with the upper surface 21 a of the bottom portion 21 . In addition, the muffle 11 of this embodiment is made of ceramic, which is a nonmetallic heat-resistant material. Ceramics are non-metallic and inorganic solid materials other than metallic materials such as iron, aluminum, and copper, and organic materials such as plastics and wood. More specifically, the typical ceramics include old ceramics such as ceramics, refractories (refractory bricks), glass, and cement, and new ceramics (fine ceramics).

The muffle 11 is divided into multiple parts. Specifically, the muffle 11 is composed of a plurality of divided bodies 40 arranged by arranging the plurality of divided bodies 40 in the conveying direction X of the work W. As shown in FIG. The divided body 40 is composed of a lower divided body 11A that forms the bottom portion 21 and an upper divided body 11B that forms the side wall portion 22 and the ceiling portion 23. As shown in FIG.

As shown in FIG. 1, both ends of the muffle 11 in the conveying direction X of the workpiece W, in other words, relatively low-temperature regions at the inlet and outlet of the workpiece W in the muffle 11 have cylindrical or gate-shaped of metal chambers 18 are connected.

The conveying device 12 conveys the workpiece W in the longitudinal direction X of the muffle 11 in the heat treatment space S within the muffle 11 . In this embodiment, a plurality (for example, three) of conveying devices 12 are arranged side by side in the width direction Y of the muffle 11 at intervals. The conveying device 12 of this embodiment is a chain conveyor having a conveying chain 12a and sprockets 12b and 12c. Chain 12 a moves on rails 21 b provided on top surface 21 a of bottom portion 21 of muffle 11 . The chain 12a is wound around the drive sprocket 12b and the driven sprocket 12c and moves in the muffle 11 in the longitudinal direction X. As shown in FIG. A tray T for placing the work W thereon is provided on the chain 12a. In this embodiment, a plurality of trays T are stacked in the vertical direction Z at intervals, and a workpiece W is placed on each tray T. As shown in FIG. The transport device 12 may be of other types, such as a belt conveyor or roller conveyor.

As shown in FIG. 2, the heat insulation walls 13 include a lower heat insulation wall 13a arranged below the muffle 11, side heat insulation walls 13b arranged on both sides of the muffle 11 in the width direction Y, and an upper heat insulation wall above the muffle 11. It has a wall 13c. The muffle 11 is arranged in a space surrounded by a lower heat insulating wall 13a, a side heat insulating wall 13b, and an upper heat insulating wall 13c. The heat insulating wall 13 can be made of a heat insulating material formed into a thick plate using ceramic fibers, for example.

The heating device 14 has a heater arranged below the muffle 11 . The heating device 14 heats the muffle 11 from the outside to raise the temperature of the heat treatment space S inside the muffle 11 to a predetermined temperature. As the heating device 14, an electric resistance heating type or a gas combustion heating type can be used. The arrangement and form of the heating device 14 are not particularly limited. The heating device 14 may be embedded in the heat insulating wall 13 .

A gas supply pipe 15 generates a predetermined atmosphere by supplying gas into the muffle 11 . In this embodiment, for example, nitrogen gas is used. The gas supply pipe 15 is arranged along the upper surface 21 a of the bottom portion 21 of the muffle 11 . Specifically, the gas supply pipe 15 is placed on the upper surface 21a of the bottom portion 21 and supported from below by the upper surface 21a.

The gas supply pipe 15 extends in the direction X in which the workpiece W is conveyed. The gas supply pipes 15 are provided on both outer sides of the conveying device 12 in the width direction Y of the muffle 11 and between adjacent conveying devices 12 . Therefore, in this embodiment, a total of four gas supply pipes 15 are provided inside the muffle 11 . An outer peripheral surface of the gas supply pipe 15 is formed with a discharge port for discharging gas. A plurality of discharge ports are formed at intervals in the conveying direction X of the workpiece W. As shown in FIG. The gas supply pipes 15 arranged on both outer sides of the conveying device 12 in the width direction Y of the muffle 11 are formed with discharge ports so as to discharge gas obliquely upward toward the work W positioned inside in the same direction Y. It is Each of the gas supply pipes 15 arranged between the adjacent conveying devices 12 is formed with a discharge port so as to discharge the gas obliquely upward toward the works W arranged on both sides of the muffle 11 in the width direction Y. It is

A gas introduction pipe 16 is arranged adjacent to one gas supply pipe 15 of the two gas supply pipes 15 arranged between adjacent conveying devices 12 . In this embodiment, two gas introduction pipes 16 are arranged adjacent to each other on both sides of the gas supply pipe 15 in the width direction Y of the muffle 11 . This gas introduction pipe 16 is used to introduce the gas inside the muffle 11 and send it out of the muffle 11 in order to detect the concentration of a predetermined gas inside the muffle 11 .

FIG. 4 is a schematic perspective view showing the muffle and cover;
As shown in FIGS. 2-4, the cover 30 covers the muffle 11 from the outside. Specifically, the cover 30 covers the side wall portion 22 and the ceiling portion 23 of the muffle 11 from the outside. Therefore, the cover 30 is formed in a U-shape with an open bottom by a portion 30a covering the side wall portion 22 and a portion 30b covering the ceiling portion 23. As shown in FIG. The cover 30 is made of a heat-resistant metal such as a nickel alloy such as Inconel 601 (“Inconel” is a registered trademark) or stainless steel such as SUS310 or SUS304.

Cover 30 includes a main cover 31 and a sub cover 32 . A plurality of main covers 31 and sub-covers 32 are provided. The main covers 31 and the sub-covers 32 are alternately arranged in the work W transport direction X. As shown in FIG. Therefore, the plurality of main covers 31 are spaced apart in the work W transport direction X, and the multiple sub-covers 32 are spaced apart in the work W transport direction X. As shown in FIG. The interval between the main covers 31 arranged side by side in the conveying direction X of the workpiece W is set so that the main covers 31 do not interfere with each other when the main covers 31 expand due to heat. The interval between the sub-covers 32 arranged side by side in the conveying direction X of the work W is such that the sub-covers 32 do not interfere with each other when the sub-covers 32 expand due to heat.

Each main cover 31 covers a boundary K1 between adjacent divisions 40 of the muffle 11 . Specifically, the main cover 31 has a length slightly longer than the length of the divided bodies 40 in the conveying direction X of the workpiece W in the same direction X, and has two boundaries K1 located on both sides of each divided body 40. It straddles and covers these two boundaries K1 from the outside. Therefore, the main cover 31 prevents the atmosphere gas in the muffle 11 from leaking from the boundary K<b>1 of the divided body 40 and the external gas from entering the muffle 11 .

Each sub cover 32 is arranged over the main covers 31 adjacent to each other in the work W transport direction X. As shown in FIG. In other words, the sub cover 32 is arranged across the adjacent main covers 31 to bridge the two main covers 31 . Each sub cover 32 covers the edge of the adjacent main cover 31 from the outside. Therefore, the main cover 31 and the sub cover 32 overlap each other at the ends in the transport direction X of the work W. As shown in FIG. The sub cover 32 is formed to be one size larger than the main cover 31 and is arranged with a gap corresponding to the thickness of the main cover 31 with respect to the outer surface of the muffle 11 .

The sub cover 32 presses the main cover 31 by covering the end of the main cover 31 from the outside. In particular, the portion of the main cover 31 that covers the ceiling portion 23 of the muffle 11 is pressed from above by the weight of the sub cover 32 . As a result, the sub cover 32 acts as a "weight" for the main cover 31, and the lifting of the main cover 31 from the muffle 11 can be suppressed. A portion of the main cover 31 that covers the side wall portion 22 of the muffle 11 is pressed from the outside in the width direction Y of the muffle 11 by a sub cover 32 . Thereby, in the width direction Y of the muffle 11 , the main cover 31 can be prevented from spreading outward or floating from the muffle 11 . Therefore, the auxiliary cover 32 enhances the effect of the main cover 31 blocking the boundary K1 of the divided body 40, and can effectively suppress leakage of ambient gas and intrusion of external gas from the boundary K1. In addition, the sub-cover 32 further suppresses the entry of outside air into the muffle 11 by blocking the space between the adjacent main covers 31 .

The main cover 31 and the sub-cover 32 prevent the heat of the muffle 11 from escaping to the outside by covering the entire muffle 11 from the outside. In addition, the main cover 31 and the sub cover 32 suppress unevenness in heat throughout the muffle 11 . The main cover 31 and the sub cover 32 are made of metal and have the property of adsorbing oxygen. Therefore, for example, when the inside and outside of the muffle 11 are filled with a predetermined gas such as nitrogen gas and the atmosphere inside the muffle 11 is to be maintained in a low-oxygen state, oxygen can be adsorbed by the main cover 31 and the sub-cover 32. , the atmosphere in the muffle 11 can be easily maintained in a low-oxygen state.

The cover 30 is divided into a main cover 31 and a sub-cover 32, and the volume per single cover is small. Thermal deformation of 32 can be reduced. Therefore, it is possible to prevent the main cover 31 from rising from the boundary K<b>1 of the divided body 40 . Similarly, since deformation of the sub cover 32 due to heat can be reduced, the sub cover 32 is prevented from being lifted from the main cover 31, and the effect of the sub cover 32 pressing the main cover 31 can be ensured.

The main cover 31 and the sub cover 32 have substantially the same length in the work W transport direction X. As shown in FIG. Therefore, both have approximately the same amount of deformation due to heat. That is, since it can be assumed that the main cover 31 and the sub-cover 32 have substantially the same range where there is a risk of warping and floating due to heat, the overlap of the covers 31 and 32 required for the sub-cover 32 to hold the main cover 31 Makes it easier to manage your bills. As a result, the gaps between the covers 31 and 32 are also suppressed, and the occurrence of gaps between the muffle 11 and the cover 30 can be suppressed.

5(a) is a cross-sectional view of the cover at the C portion in FIG. 3, and FIG. 5(b) is a view in the direction of arrow D in FIG. 5(a).
Relative movement in the transport direction X of the workpiece W is restricted between the main cover 31 and the sub cover 32 . Specifically, a bar-shaped projection 51 is provided on the outer surface of the end portion of the main cover 31 so as to protrude upward. A hole 52 into which the projection 51 is inserted is formed at the end of the sub cover 32 . The hole 52 is an elongated hole elongated in the direction X in which the workpiece W is conveyed. In this embodiment, projections 51 and holes 52 are provided in a portion 30 b of the main cover 31 and the sub cover 32 that covers the ceiling portion 23 of the muffle 11 . However, the protrusions 51 and the holes 52 may be provided in the portion 30a of the main cover 31 and the sub-cover 32 that covers the side wall portion 22 of the muffle 11 .

The main cover 31 and the sub cover 32 are allowed to move relative to each other within the length of the hole 52 when they are extended in the transport direction X of the work W by heat, and within the range exceeding the length of the hole 52 , the relative movement of the workpiece W in the transport direction X is restricted. By restricting the relative movement, the main cover 31 and the sub cover 32 are kept in an overlapping state, and the main cover 31 is kept covering the boundary K1 between the adjacent divided bodies 40 . Therefore, leakage of ambient gas from the boundary K1 is suppressed. Here, the projections 51 and the holes 52 constitute a holding mechanism 50 that holds the state in which the main cover 31 covers the boundaries K1 of the adjacent divided bodies 40 . In addition, since the holding mechanism 50 keeps the muffle 11 covered from the outside by the main cover 31 and the sub-cover 32, the heat of the muffle 11 can be suppressed from escaping to the outside.

The length of the hole 52 of the holding mechanism 50 (the amount of relative movement between the main cover 31 and the sub-cover 32) depends on the size of the overlapping margin between the main cover 31 and the sub-cover 32 and the expansion of the main cover 31 and the sub-cover 32 due to heat. A state in which the main cover 31 and the sub-cover 32 overlap and a state in which the main cover 31 covers the boundary K1 are set according to the amount and the like.

6 is a cross-sectional view of the cover at E section of FIG. 3. FIG.
One end of the main cover 31 arranged at the end of the work W in the conveying direction X is connected to the sub cover 32 via the holding mechanism 50 , and the other end is connected to the inlet and outlet of the muffle 11 . is fixed to the metal chamber 18. Specifically, a bar-shaped protrusion 53 is provided on the outer surface of the metal chamber 18 so as to protrude upward, and a hole 54 into which the protrusion 53 is inserted is formed at the end of the main cover 31 . The hole 54 is a round hole having an inner diameter slightly larger than the diameter of the projection 53 . Accordingly, the main cover 31 with the holes 54 formed therein is substantially fixed to the metal chamber 18 . In this way, by fixing the main covers 31 arranged at both ends of the workpiece W in the direction X in the same direction X, it is possible to limit the amount of movement of the other main covers 31 and sub-covers 32 arranged therebetween. It is possible to suppress detachment of the main cover 31 and the sub cover 32 from each other. Furthermore, it is possible to prevent each main cover 31 from deviating from the boundary K1 of the divided body 40 due to accumulation of movements of these covers 31 and 32 .

FIG. 7 is a cross-sectional view of the muffle and cover in section F of FIG. 2;
As shown in FIG. 7, a portion 30a of the main cover 31 that covers the side wall portion 22 of the muffle 11 covers a boundary K2 between the side wall portion 22 and the bottom portion 21 from the outside. Therefore, leakage of ambient gas from the boundary K2 and entry of external gas from the boundary K2 can be suppressed.

FIG. 8 is a cross-sectional view showing a cover according to a second embodiment of the invention.
In this embodiment, a plurality of main covers 31 cover one boundary K1 between adjacent divided bodies 40, respectively. Therefore, each main cover 31 has a shorter length in the transport direction X of the work W than the main cover 31 of the first embodiment. In addition, the sub-covers 32 overlapping the main cover 31 are spaced apart from each other in the conveying direction X of the workpiece W. As shown in FIG.

Also in this embodiment, the same effects as those of the above-described embodiment are obtained. Moreover, in this embodiment, the plurality of main covers 31 cover one boundary K1 between the adjacent divided bodies 40 respectively. Therefore, since the main cover 31 only needs to cover the periphery of at least one boundary K1, the length of the work W in the transport direction X can be made shorter than in the first embodiment. Therefore, the area of the main cover 31 can be made smaller than that of the main cover 31 of the first embodiment, and the amount of deformation due to heat can be made smaller than that of the main cover 31 of the first embodiment. Therefore, the lifting of the main cover 31 from the divided body 40 can be further suppressed, and the leakage of ambient gas from the boundary K1 to the outside of the muffle 11 and the infiltration of external gas into the muffle 11 can be suppressed.

FIG. 9 is a cross-sectional view showing a holding mechanism according to a third embodiment of the invention.
In this embodiment, the form of the holding mechanism 50 is different from that of the above embodiment.
In this embodiment, a bar-shaped protrusion 55 is provided on the inner surface of the end of the sub cover 32 so as to protrude downward. The amount of protrusion of the protrusion 55 is smaller than the thickness of the main cover 31 . A groove 56 into which a protrusion 55 is inserted is formed in the outer surface of the end of the main cover 31 . The groove 56 is a long groove that is long in the direction X in which the workpiece W is conveyed.

Therefore, in the present embodiment as well, the relative movement of the main cover 31 and the sub-cover 32 in the transport direction X of the work W is restricted within the range of the length of the groove 56, and the main cover 31 and the sub-cover 32 do not overlap. It is held, and the state where the main cover 31 covers the boundary K1 is held.

In this embodiment, the grooves 56 can be changed to holes that penetrate the main cover 31 . Further, in the first embodiment shown in FIG. 5, the amount of protrusion of the projections 51 can be made smaller than the thickness of the sub cover 32, and the holes 52 can be changed to grooves (long grooves) formed in the lower surface of the sub cover 32. .

As described above, the continuous heat treatment furnace 10 according to the embodiment described above includes a non-metal muffle 11 in which a heat treatment space S for heat-treating the workpiece W being conveyed is formed, and a metal and a cover 30 of The muffle 11 includes at least three divided bodies 40 (for example, three divided bodies arranged side by side in FIGS. 3 and 8; hereinafter, these are referred to as "first divided body", "second divided body", and "third divided body"). (also called "body"). These first to third divided bodies 40 are arranged in the conveying direction X of the workpiece W. As shown in FIG. The cover 30 includes a main cover (hereinafter also referred to as “first main cover”) 31 that covers the boundary K1 between the first divided body 40 and the second divided body 40, the second divided body 40 and the third divided body 40. and a main cover (hereinafter, also referred to as a “second main cover”) 31 covering the boundary K1. With such a configuration, the plurality of boundaries K1 of the divided body 40 are covered with the plurality of main covers 31. As shown in FIG. Therefore, the cover 30 is divided into a plurality of main covers 31 to reduce the area per single cover. Therefore, deformation of each main cover 31 due to heat can be suppressed compared to the case where the cover 30 is not divided. As a result, the main covers 31 are prevented from floating from the muffle 11 , and atmospheric gas leakage from the boundary K<b>1 to the outside of the muffle 11 and external gas from entering the muffle 11 can be suppressed.

In the above-described embodiment, the cover 30 has the sub-cover 32 arranged across the first main cover 31 and the second main cover 31 and overlapping the first main cover 31 and the second main cover 31 from the outside. . Therefore, the first and second main covers 31 are pressed from the outside by the sub-cover 32 , and the boundary K1 between the adjacent divided bodies 40 can be covered by the first and second main covers 31 . In particular, the first and second main covers 31 are pressed from above by the weight of the sub cover 32 . Therefore, the sub-cover 32 acts as a weight on the first and second main covers 31 , and the first and second main covers 31 are restrained from rising from the muffle 11 .

In the first embodiment, the muffle 11 further has the divided body 40 (hereinafter also referred to as "fourth divided body") arranged side by side with the third divided body 40 in the conveying direction X of the work W, and the second The main cover 31 also covers the boundary K1 between the third divided body 40 and the fourth divided body 40 . In other words, the cover 30 has a second main cover 31 covering the boundaries K1. Therefore, compared to the case where the second main cover 31 covers only one boundary K1, the total number of covers 30 can be reduced.

In the above-described embodiment, the continuous heat treatment furnace 10 includes the holding mechanism 50 that restricts relative movement between the first main cover 31 and the second main cover 31, and the sub cover 32 straddling them. As a result, it is possible to prevent the first and second main covers 31 and the sub cover 32 from being detached from each other. Furthermore, by providing the holding mechanism 50, it is possible to prevent the first and second main covers 31 from being displaced from the boundary K1. Therefore, it is possible to suppress leakage of ambient gas from the muffle 11 and infiltration of external gas into the muffle 11 .

The present invention is not limited to the above embodiments, and can be modified as appropriate within the scope of the invention described in the claims.

For example, the main cover 31 may have a length in the transport direction X of the workpiece W that covers three or more boundaries K1. Moreover, the cover 30 may include a plurality of types of main covers 31 that differ in the number of boundaries K1 that can be covered. For example, for manufacturing reasons such as ease of production of the muffle 11, if each divided body 40 is formed small and a large number of the divided bodies 40 are arranged, a plurality of types can be used as described above. It is more effective to combine the main covers 31 of the two.

For example, the muffle 11 is composed of the side wall portion 22 and the ceiling portion 23, and the bottom portion 21 separately, but the present invention is not limited to this. For example, the muffle 11 may be integral as a whole. Further, the muffle 11 may have the side wall portion 22 and the bottom portion 21 as one piece, and the ceiling portion 23 as separate pieces. In addition, the muffle 11 may be configured with separate upper and lower parts with a middle portion in the vertical direction Z of the side wall portion 22 as a boundary.

Although the cover 30 covers the side wall portion 22 and the ceiling portion 23 of the muffle 11, it may cover either one. Also, the cover 30 may cover the bottom portion 21 .

10: Continuous Heat Treatment Furnace 11: Muffle 30: Cover 31: Main Cover 32: Sub Cover 40: Divided Body 50: Holding Mechanism K1: Boundary K2: Boundary S: Heat Treatment Space W: Workpiece X: Transfer Direction

Claims (3)

A ceramic muffle in which a heat treatment space for heat-treating a workpiece is formed, and a metal cover covering the muffle, wherein the muffle is divided into a plurality of divided muffles. are arranged side by side so as to connect the heat treatment space,
the cover includes a main cover that covers a boundary between adjacent muffles in the muffle divided into a plurality of sections;
and a sub cover bridging the plurality of main covers. 2. The thermal processing apparatus of claim 1, wherein at least one said main cover covers a plurality of said boundaries. 3. The heat treatment apparatus according to claim 1, further comprising a holding mechanism for restricting relative movement between said main cover and said sub-cover.

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