CN112857057A

CN112857057A - Heat treatment furnace

Info

Publication number: CN112857057A
Application number: CN202011341186.9A
Authority: CN
Inventors: 森元阳介
Original assignee: Shimadzu Industrial Systems Co Ltd
Current assignee: Shimadzu Industrial Systems Co Ltd
Priority date: 2019-11-28
Filing date: 2020-11-25
Publication date: 2021-05-28
Anticipated expiration: 2040-11-25
Also published as: JP2021085623A; CN112857057B; JP7338818B2

Abstract

The invention provides a heat treatment furnace capable of uniformly cooling a processed object. The heat treatment furnace comprises: a pressure vessel; a thermal insulator; a heater; a first port for supplying a cooling gas to an internal space of the pressure vessel; a second port for discharging the cooling gas to the outside of the pressure vessel; a first through hole formed in the heat insulator, for guiding the cooling gas to an internal space formed by the heat insulator; a second through hole formed in the heat insulator and configured to discharge the cooling gas from an internal space formed by the heat insulator; a first fan for cold-circulating the cooling gas; a cooling device for cooling the cooling gas; and a sealing box which is arranged in an internal space formed by the heat insulator, accommodates the object to be processed, is cooled by cooling gas, and cools the object to be processed by heat radiation.

Description

Heat treatment furnace

Technical Field

The invention relates to a heat treatment furnace.

Background

Conventionally, a material to be treated, which includes a metal, a magnetic material, or the like, is placed in a heat treatment furnace and heat-treated in a vacuum or pressurized environment. For example, patent document 1 below discloses a heat treatment furnace in which cooling fins are provided on an inner surface of a furnace lid of a pressure vessel. The cooling fins enlarge the area for cooling the gas flowing in the pressure vessel and improve the cooling capacity.

[ Prior art documents ]

[ patent document ]

[ patent document 1] Japanese patent application laid-open No. 2005-121308

Disclosure of Invention

[ problems to be solved by the invention ]

Since a plurality of objects to be processed are processed at once in the heat treatment furnace, it is preferable that all the positions of the objects to be processed in the heat treatment furnace are processed under the same condition. For example, if all the objects to be processed are not uniformly cooled, a part of the objects to be processed may become defective. If the object to be processed becomes a defective product, the yield is deteriorated. Patent document 1 discloses that the cooling capacity is improved, but does not disclose that the object to be treated is uniformly cooled.

Accordingly, an object of the present invention is to provide a heat treatment furnace capable of uniformly cooling a workpiece.

[ means for solving problems ]

In order to solve the above problems, the heat treatment furnace of the present invention has the following configuration.

The heat treatment furnace of the present invention comprises: a container-shaped pressure vessel; a heat insulator disposed in an internal space of the pressure vessel; a heater disposed in an internal space formed by the heat insulator; a first port for supplying a cooling gas to an internal space of the pressure vessel; a second port for discharging a cooling gas to the outside of the pressure vessel; a first through hole formed in the heat insulator, the first through hole being configured to guide the cooling gas to an internal space formed by the heat insulator; a second through hole formed in the heat insulator, for discharging the cooling gas from an internal space formed by the heat insulator; a first fan that circulates the cooling gas; a cooling device for cooling the cooling gas; and a sealing box which is arranged in an internal space formed by the heat insulator, accommodates the object to be processed, is cooled by the cooling gas, and cools the object to be processed by heat radiation.

[ Effect of the invention ]

Conventionally, the cooling gas flows in the front-rear direction of the pressure vessel, and according to the present invention, the cooling gas flows from the first port to the second port, whereby the cooling gas flows so as to surround the seal box. The cooling gas uniformly hits the seal box before hitting the object to be processed, so that the seal box is uniformly cooled. The radiation cooling can be performed on the processed object, so that the processed object can be uniformly cooled.

Drawings

Fig. 1 is a view showing the structure of a heat treatment furnace according to the present invention.

Fig. 2 is a diagram showing the flow of gas when the sealed box cover is opened.

Fig. 3 is a diagram showing the flow of gas when the sealed box cover is opened.

Fig. 4 is a sectional view taken along line a-a of fig. 2.

Fig. 5 is a view showing the flow of gas when the heat insulator cover is opened.

Fig. 6 is a view showing the flow of gas when the heat insulator cover is opened.

FIG. 7 is a view showing the structure of a heat treatment furnace including shower plates.

[ description of symbols ]

10: heat treatment furnace

12: pressure vessel

14: inner space of pressure vessel

16: heat insulator

18: inner space of heat insulator

20: heating device

22: object to be treated

24: sealing box

26. 28: port(s)

30. 32: through hole

34: cooling unit

36: inner space of sealed box

68: back insulation body

72: second port cover

74: first fan

76: cooling device

80: the first motor

122: spray plate

124: openings of shower plate

Detailed Description

The heat treatment furnace of the present invention will be described with reference to the accompanying drawings. Although a plurality of embodiments are described, the same components may be given the same reference numerals and the description thereof may be omitted even in different embodiments. The x-direction, y-direction, and z-direction in each drawing are mutually orthogonal directions.

[ embodiment 1]

The heat treatment furnace 10 of the present application shown in fig. 1 includes: a container-shaped pressure vessel 12; an insulator 16 disposed in the internal space 14 of the pressure vessel 12; a heater 20 disposed in the internal space 18 of the heat insulator 16; a sealed box (inner box) 24 for accommodating the object to be processed 22; a first port 26 for supplying a cooling gas to the internal space 14 of the pressure vessel 12; a second port 28 for discharging the cooling gas to the outside of the pressure vessel 12; a first through hole 30 for guiding the cooling gas to the internal space 18 of the heat insulator 16; a second through hole 32 for discharging the cooling gas from the internal space 18 of the heat insulator 16; and a cooling unit 34 for circulating a cooling gas.

Further, the heat treatment furnace 10 includes: a gas source 38 for introducing gas into the internal space 14 of the pressure vessel 12 and the internal space 36 of the seal box 24; and a pump 40 for depressurizing the internal space 14 of the pressure vessel 12 and the internal space 36 of the seal box 24.

The heat treatment furnace 10 is a furnace for performing sintering, semi-sintering, calcination, degreasing, welding, metallization, quenching, solution treatment, tempering, annealing, aging heat treatment, or the like.

[ pressure vessel ]

As shown in fig. 2 and 3, the pressure vessel 12 includes a vessel body 42 and a vessel lid 44. The container body 42 has a cylindrical shape (fig. 4). The container lid 44 opens and closes both ends of the container body 42. When both ends of the container body 42 are closed by the container lid 44, the internal space 14 of the pressure container 12 becomes an airtight space. The interior space 14 of the pressure vessel 12 is depressurized, or pressurized. The pressure vessel 12 has a pressure resistance of, for example, about 10MPa, and can be changed according to various designs. The pressure vessel 12 has a double structure including an inner wall 46 and an outer wall 48, and the cooling liquid flows between the inner wall 46 and the outer wall 48. When the temperature of the internal space 14 is lowered, it may be lowered by the cooling liquid.

[ Heat insulator ]

The insulator 16 is disposed in the internal space 14 of the pressure vessel 12. The insulator 16 includes an insulator body 50 and an insulator cover 52. The insulator body 50 is cylindrical. As shown in fig. 2, the insulator body 50 includes an insulator protrusion 54, the insulator protrusion 54 interfacing with the inner wall 46 of the pressure vessel 12. The insulator protrusion 54 is provided at the upper and lower portions of both ends in the longitudinal direction of the insulator 16. There is a gap between the pressure vessel 12 and the insulator 16. The insulator cover 52 opens and closes both ends of the insulator main body 50. The heat insulator cover 52 includes an opening/closing device (not shown) for opening/closing the heat insulator cover 52 in a state where the container cover 44 is closed. The heat insulator 16 includes a heat-resistant material such as graphite felt or graphite foil.

[ Heater ]

A heater 20 is disposed in the internal space 18 of the heat insulator 16. The heater 20 may be a rod heater (rod heater) made of graphite. The heater 20 is disposed in parallel with the seal box 24. Further, a plurality of heaters 20 are arranged so as to surround the seal box 24 (fig. 4). The heater 20 generates heat by supplying three-phase ac power from electrodes (not shown).

[ sealed case ]

A seal box 24 is disposed in the internal space 18 of the heat insulator 16. The seal box 24 contains graphite or the like. The seal box 24 includes a seal box body 56 and a seal box cover 58. The seal box body 56 has a cylindrical shape. The seal case cover 58 opens and closes both ends of the seal case body 56. As shown in fig. 2 and 3, an opening/closing device 60 that seals the cover 58 is included in order to seal the cover 58 so as to be openable and closable. The opening/closing device 60 is attached to the heat insulator cover 52, and moves the sealed box cover 58 toward the heat insulator cover 52. Both ends of the seal case body 56 are closed by the seal case lid 58, whereby the internal space of the seal case 24 is sealed.

[ treated article ]

The object 22 to be treated is disposed in the internal space 36 of the sealed box 24. The material of the object 22 is a superhard metal, an iron-based metal, a nonferrous metal, a magnetic material, ceramics, graphite, high-speed steel, die steel, low alloy steel, or the like, and the metal includes an alloy. The object to be treated 22 is a powder or a solid having a predetermined shape. By housing the object to be treated 22 in the seal box 24, the adhesive (gas and wax) released from the object to be treated 22 when the object to be treated 22 is degreased can be prevented from being directed to the outside of the seal box 24. Contamination of the inner wall 46 of the pressure vessel 12, the heat insulator 16, the heater 20, and the like can be prevented.

[ Port ]

The heat treatment furnace 10 includes a first port 26 for supplying a cooling gas into the internal space 14 of the pressure vessel 12 and a second port 28 for discharging the cooling gas. A first port 26 is provided in the lower portion of the pressure vessel 12. A second port 28 is provided in the upper portion of the pressure vessel 12. The first port 26 and the second port 28 are disposed at positions symmetrical with respect to the center of the pressure vessel 12. The cooling gas flows from the first port 26 across the interior space 14 of the pressure vessel 12 to the second port 28. The number of the

ports

26 and 28 is not limited.

[ through-holes ]

The heat insulator 16 includes a first through hole 30 for supplying the cooling gas to the internal space 18 of the heat insulator 16 and a second through hole 32 for discharging the cooling gas. The first through hole 30 is provided at a lower portion of the insulator body 50. The second through hole 32 is provided in the upper portion of the insulator body 50. The first through-hole 30 and the second through-hole 32 are disposed at positions symmetrical with respect to the center of the insulator 16. The cooling gas flows from the first through hole 30 to the second through hole 32 across the internal space 18 of the heat insulator 16. The number of through-

holes

30 and 32 is not limited, and the number of through-

holes

30 and 32 is not limited. So that the cooling gas flows uniformly in the inner space 18 of the insulator 16.

In order to guide the cooling gas from the first port 26 to the first through hole 30 and from the second through hole 32 to the second port 28, a heat insulating member 64 (fig. 4) is provided between the pressure vessel 12 and the heat insulator 16. The heat insulating member 64 connects the container body 42 and the heat insulator body 50. Both ends of the heat insulating member 64 are in contact with the heat insulator protrusion 54. The container main body 42, the insulator main body 50, the insulating member 64, and the insulator protrusion 54 form an air passage 66 for cooling air.

The cooling air passage 66 may include a heat insulating back insulator 68 in contact with the inner wall 46 of the container main body 42. The back insulator 68 includes a through hole 70 that communicates with the first port 26 and the second port 28. The first through-hole 30 and the second through-hole 32 are formed in the heat insulator 16, so that the heat insulating performance of the internal space 18 of the heat insulator 16 may be lowered, but the lowering of the heat insulating performance is prevented by the back heat insulator 68.

A second port cover 72 (fig. 1) may also be included to open and close the second port 28. The second port cover 72 is opened and closed by an opening and closing device (not shown). The second port cover 72 comprises an insulating material. When the object 22 is heat-treated, the second port cover 72 is closed to insulate the internal space 18 of the heat insulator 16.

[ Cooling Unit ]

As shown in fig. 1, the cooling unit 34 includes a first fan 74 and a cooling device 76. The first fan 74 and the cooling device 76 are housed in a housing 78. The first fan 74 circulates the cooling gas. A first motor 80 is provided for rotating the first fan 74. The cooling device 76 is a water-cooled heat exchanger. The cooling unit 34 and the first port 26 are connected by a first pipe 82, and the cooling unit 34 and the second port 28 are connected by a second pipe 84. The cooling gas cooled by the cooling device 76 is sent into the pressure vessel 12 through the first pipe 82 and the first port 26. Further, the cooling gas returns to the cooling unit 34 through the second port 28 and the second pipe 84. The cooling gas is cooled by the cooling unit 34 and is again delivered to the pressure vessel 12. Further, valves may be provided in the first pipe 82 and the second pipe 84, respectively, to control the flow of the cooling gas.

The cooling unit 34 may be mounted directly to the pressure vessel 12 or may be located remotely from the pressure vessel 12. The cooling unit 34 is installed at any place according to the area of the installation place of the heat treatment furnace 10 and the size of the pressure vessel 12.

[ gas source ]

The gas source 38 stores, generates, or stores and generates nitrogen, argon, hydrogen, carbon monoxide, helium, methane, and the like. The gas source 38, the interior space 14 of the pressure vessel 12, and the interior space 36 of the seal box 24 are connected by a third tube 90. The third pipe 90 is branched and provided with a valve 92 and a valve 94, respectively. The flow rate of the gas can be controlled by opening and closing the

valves

92 and 94. Gas is introduced from the gas source 38 into the internal space 14 of the pressure vessel 12 and the internal space 36 of the seal box 24 via the third pipe 90. The gas source 38 may be provided in plural numbers, and plural kinds of gases may be supplied to the internal space 14 of the pressure vessel 12 and the internal space 36 of the seal box 24. A plurality of third pipes 90 are provided to supply a plurality of gases. Further, since the insulator 16 is not completely airtight, gas can be introduced from the internal space 18 of the insulator 16 into the internal space 14 of the pressure vessel 12.

[ Pump ]

The pump 40 evacuates the internal space 14 of the pressure vessel 12 and the internal space 36 of the seal box 24. The pump 40 and the pressure vessel 12 are connected by a fourth pipe 96, and the pump 40 and the seal box 24 are connected by a fifth pipe 98. The internal space 14 of the pressure vessel 12 and the internal space 36 of the seal box 24 are depressurized by the pump 40. The fourth pipe 96 and the fifth pipe 98 include a valve 100 and a valve 102, respectively, and exhaust may be controlled by opening and closing the valve 100 and the valve 102.

The fifth pipe 98 includes a wax tank 104 and a wax filter 106. The adhesive degreased in the object 22 is captured by the wax pot 104 and the wax filter 106. The adhesive does not reach the pump 40.

[ others ]

A second fan 108 may also be included in the interior space 14 of the pressure vessel 12. The second fan 108 rotates when the container lid 44 is closed and the insulator lid 52 is opened. The gas circulates through the internal space 14 of the pressure vessel 12 and the internal space 18 of the insulator 16. The gas may also be a gas introduced into the

interior space

14, 18 from a gas source 38. There are also situations where the sealed cover 58 is opened. A second motor 110 for rotating the second fan 108 is mounted to the container cover 44.

A guide 112 may also be provided that connects the insulator body 50 with the second fan 108. The direction of the circulating gas is determined by the guide 112. If the direction of the gas is specified, the shape of the guide 112 is not limited. Since the pressure vessel 12 has a double structure and a coolant flows through the interior thereof, the circulating gas is cooled by the coolant. Further, a water-cooled heat exchanger may be disposed between the second fan 108 and the insulator main body 50, and the gas may be cooled by the heat exchanger.

The heat treatment furnace 10 includes a thermometer (not shown) for measuring the temperature of the internal space 18 of the heat insulator 16 or the internal space 36 of the seal box 24, and a pressure gauge (not shown) for measuring the pressure of the internal space 14 of the pressure vessel 12. The power supplied to the heater 20 is controlled in accordance with the temperature measured by the thermometer. The gas source 38 and pump 40 are controlled in correspondence with the pressure measured by the pressure gauge.

[ Heat treatment ]

Next, a heat treatment using the heat treatment furnace 10 of the present application will be described. The heat treatment described above is an example, and is appropriately changed depending on the type of the object 22 to be treated and the treatment method.

(1) The object 22 to be treated is accommodated in the internal space 36 of the sealed box 24, and the sealed box cover 58, the heat insulator cover 52, and the container cover 44 are closed.

(2) The internal space 14 of the pressure vessel 12, the internal space 18 of the heat insulator 16, and the internal space 36 of the seal box 24 are controlled to predetermined pressures by exhausting gas with the pump 40. Gas is introduced from a gas source 38 into the internal space 14 of the pressure vessel 12, the internal space 18 of the heat insulator 16, and the internal space 36 of the seal box 24, and the

spaces

14, 18, and 62 are filled with a predetermined gas.

(3) An electric current is passed through the heater 20 to raise the temperature of the internal space 18 of the heat insulator 16. The sealed box 24 disposed in the internal space 18 of the heat insulator 16 is heated, and the object 22 to be treated is further heated. At the time of warming, the port cover 72 is closed.

The temperature of the object 22 to be treated located in the internal space 36 of the seal box 24 rises, and the object 22 to be treated is degreased. During degreasing, the pump 40 is driven, and the binder generated from the object 22 is accumulated in the wax tank 104 and the wax filter 106 located in the middle of the fifth pipe 98.

After the degreasing of the object 22 is completed, the current flowing through the heater 20 is increased to raise the temperature of the object 22, and the heat treatment is performed. For example, the object 22 is sintered at about 1600 ℃.

(4) After the object 22 is heat-treated, the object 22 is cooled. The cooling of the object 22 to be treated is performed in two stages. In the first stage, the port cover 72 is opened, and the first fan 74 is rotated. As indicated by reference numeral w1 in fig. 2, the cooling gas is supplied to the internal space 18 of the heat insulator 16 through the first port 26 and the first through hole 30. The cooling gas is blown toward the lower portion of the seal box 24. Thereafter, as indicated by symbol w1 of fig. 4, the cooling gas is circulated around the seal box 24. The object 22 to be processed disposed in the internal space 36 is cooled by heat radiation by cooling gas through the seal box 24.

As shown in fig. 2, the y direction (height direction) of the seal box 24 is shorter than the x direction (length direction). The cooling gas uniformly hits the seal box 24 in the y direction, and thus the seal box 24 is easily and uniformly cooled. The sealed box 24 uniformly cools the object 22 to be treated.

As shown in fig. 2 and 3, the sealed cover 58 is opened from the position indicated by the reference numeral 58'. A portion of the cooling gas enters the interior space 36 of the seal box 24. The object 22 is directly cooled by the cooling gas. The cooling rate of the object 22 becomes high. The presence or absence of opening and closing and the degree of opening and closing of the sealed box cover 58 during cooling are appropriately changed according to the cooling method for the object 22.

The cooling gas that hits the seal box 24 passes through the second through hole 32 and the second port 28 while increasing the temperature, and returns to the cooling unit 34. The cooling device 76 of the cooling unit 34 reduces the temperature of the cooling gas. Thereafter, the cooling gas is again fed to the first port 26. That is, the cooling gas is cooled by the cooling device 76 by the circulation of the gas in the internal space 18 of the heat insulator 16, and is sent again to the internal space 18 of the heat insulator 16.

When the temperature of the object 22 to be treated is changed from high to low by the cooling in the first stage, the cooling in the second stage is performed. In the second stage, in addition to the cooling in the first stage, the insulator cover 52 is opened, and the second fan 108 is rotated. As shown by reference numeral w2 in fig. 5 and 6, the gas also circulates in the internal space 14 of the pressure vessel 12 when the insulator lid 52 is opened. The furnace is cooled by the coolant inside the double structure of the pressure vessel 12. The cooling capacity is improved and cooling is rapidly achieved. The sealed box cover 58 may also be opened in conjunction with the insulator cover 52 to allow gas to also circulate within the interior space 36 of the sealed box 24.

During cooling, gas may also be introduced from the gas source 38 into the internal space 14 of the pressure vessel 12, the internal space 18 of the insulator 16, and the internal space 36 of the seal box 24.

The boundary of the first and second stages is any temperature of the interior space 36 of the seal box 24. The temperature is appropriately changed by the object 22 to be treated. If the temperature is higher than the above temperature, the first stage is performed, and if the temperature is lower than the above temperature, the second stage is performed. The present invention cools the object 22 uniformly in the first stage and rapidly cools the object 22 in the second stage.

When the object 22 is cooled, the container lid 44, the heat insulator lid 52, and the sealed box lid 58 are opened to take out the object 22.

As described above, in the present embodiment, the object 22 to be treated disposed in the internal space 36 of the seal box 24 can be uniformly cooled by the passage of the cooling gas from the first through hole 30 to the second through hole 32. In particular, when the temperature is high, which tends to cause defective products due to uneven cooling, the object 22 to be processed is uniformly cooled, and thus the yield can be improved.

[ embodiment 2]

The positions of the first port 26 and the second port 28 may be switched relative to embodiment 1. The first port 26 is disposed at an upper portion of the pressure vessel 12, and the second port 28 is disposed at a lower portion of the pressure vessel 12. Further, the first through-hole 30 is disposed above the insulator 16, and the second through-hole 32 is disposed below the insulator 16. The cooling gas flows from the upper portion toward the lower portion of the pressure vessel 12.

[ embodiment 3]

A port cover for opening and closing the first port 26 may be provided. The port cover 72 is provided to the first port 26, the second port 28, or both the first port 26 and the

second port

28, 26. By closing the port cover 72, the heat insulating performance of the heat insulator 16 is improved. The port cover 72 is opened when the object 22 to be treated is cooled.

[ embodiment 4]

A shower plate 122 (fig. 7) may be disposed between the pressure container 12 and the heat insulator 16 in the air passage 66. The shower plate 122 has a plurality of openings 124 in the plate body. The flow of the cooling gas is made uniform by the shower plate 122. The density of the openings 124 of the shower plate 122 may vary depending on the location. For example, the density of the openings 124 is made thin at a position close to the

ports

26 and 28, and the density of the openings 124 is made dense at a position far from the

ports

26 and 28.

(first item) the heat treatment furnace of the embodiment includes: a container-shaped pressure vessel; a heat insulator disposed in an internal space of the pressure vessel; a heater disposed in an internal space formed by the heat insulator; a first port for supplying a cooling gas to an internal space of the pressure vessel; a second port for discharging a cooling gas to the outside of the pressure vessel; a first through hole formed in the heat insulator, the first through hole being configured to guide the cooling gas to an internal space formed by the heat insulator; a second through hole formed in the heat insulator, for discharging the cooling gas from an internal space formed by the heat insulator; a first fan that circulates the cooling gas; a cooling device for cooling the cooling gas; and a sealing box which is arranged in an internal space formed by the heat insulator, accommodates the object to be processed, is cooled by the cooling gas, and cools the object to be processed by heat radiation.

According to the heat treatment furnace described in the first aspect, the cooling gas flows from the first port to the second port, and the cooling gas flows so as to surround the seal box as compared with the conventional art. The sealed box is uniformly cooled, and the object to be treated is uniformly cooled.

(second item) the first port is provided in a lower portion of the pressure vessel and the second port is provided in an upper portion of the pressure vessel, or the first port is provided in an upper portion of the pressure vessel and the second port is provided in a lower portion of the pressure vessel.

According to the heat treatment furnace described in the second aspect, the cooling gas flows in the vertical direction of the seal box, and therefore the seal box is easily and uniformly cooled.

(third) the sealed box includes a cylindrical sealed box body and sealed box covers for opening and closing both ends of the sealed box body, and an opening and closing device for the sealed box covers, and the sealed box covers can be opened and closed when the cooling gas is supplied to the internal space of the heat insulator.

According to the heat treatment furnace described in the third aspect, when the sealed box is cooled, the sealed box cover can be opened, and the cooling gas can be directly applied to the object to be treated by opening the sealed box cover.

(fourth item) a shower plate is disposed between the pressure vessel and the heat insulator.

According to the heat treatment furnace of the fourth aspect, the flow of the cooling gas can be made uniform by the shower plate.

(fifth item) the first fan and the cooling device are provided outside the pressure vessel.

According to the heat treatment furnace of the fifth aspect, the first fan and the cooling device can be freely disposed outside the pressure vessel.

(sixth item) the pressure vessel includes a second fan in the inner space thereof.

According to the heat treatment furnace described in the sixth aspect, the gas can be caused to flow in the internal space of the pressure vessel.

(seventh aspect) a back insulator is disposed on an inner wall of the pressure vessel.

According to the heat treatment furnace described in the seventh aspect, the heat insulating performance lowered by the first through-hole and the second through-hole can be improved by the back insulator.

(eighth item) the first port, the second port, or both of the first port and the second port includes a port cover capable of opening and closing the ports.

According to the heat treatment furnace of the eighth aspect, the first port and the second port are closed, whereby the heat insulating performance of the heat insulator can be maintained.

The present invention may be implemented in various forms of improvement, modification, and alteration according to the knowledge of those skilled in the art without departing from the gist thereof. The embodiments described are not independent embodiments, and may be implemented by combining them as appropriate according to the knowledge of a person skilled in the art.

Claims

1. A heat treatment furnace comprising:

a container-shaped pressure vessel;

a heat insulator disposed in an internal space of the pressure vessel;

a heater disposed in an internal space formed by the heat insulator;

a first port for supplying a cooling gas to an internal space of the pressure vessel;

a second port for discharging a cooling gas to the outside of the pressure vessel;

a first through hole formed in the heat insulator, the first through hole being configured to guide the cooling gas to an internal space formed by the heat insulator;

a second through hole formed in the heat insulator, for discharging the cooling gas from an internal space formed by the heat insulator;

a first fan that circulates the cooling gas;

a cooling device for cooling the cooling gas; and

and a sealing box which is arranged in an internal space formed by the heat insulator, accommodates the object to be processed, is cooled by the cooling gas, and cools the object to be processed by heat radiation.

2. The heat treatment furnace according to claim 1, wherein the first port is provided at a lower portion of the pressure vessel and the second port is provided at an upper portion of the pressure vessel, or the first port is provided at an upper portion of the pressure vessel and the second port is provided at a lower portion of the pressure vessel.

3. The heat treatment furnace according to claim 1, wherein the seal box includes a cylindrical seal box body and a seal box cover for opening and closing both ends of the seal box body, and

comprises an opening and closing device of the sealed box cover,

the opening and closing of the sealed box cover can be performed when the cooling gas is supplied to the inner space of the heat insulator.

4. The heat treatment furnace according to claim 2, wherein the seal box includes a cylindrical seal box body and a seal box cover for opening and closing both ends of the seal box body, and

comprises an opening and closing device of the sealed box cover,

5. The heat treatment furnace according to any one of claims 1 to 4, wherein a shower plate is disposed between the pressure vessel and the heat insulator.

6. The heat treatment furnace according to any one of claims 1 to 4, wherein the first fan and the cooling device are provided outside the pressure vessel.

7. The heat treatment furnace according to any one of claims 1 to 4, wherein a second fan is included in the inner space of the pressure vessel.

8. The heat treatment furnace according to any one of claims 1 to 4, wherein a back insulator is disposed on an inner wall of the pressure vessel.

9. The heat treatment furnace according to any one of claims 1 to 4, wherein the first port, the second port, or both of the first port and the second port includes a port cover capable of opening and closing the port.