CN210620882U

CN210620882U - Heat treatment furnace

Info

Publication number: CN210620882U
Application number: CN201921177058.8U
Authority: CN
Inventors: 森元阳介
Original assignee: Shimadzu Corp
Current assignee: Shimadzu Industrial Systems Co Ltd
Priority date: 2019-04-18
Filing date: 2019-07-24
Publication date: 2020-05-26
Anticipated expiration: 2029-07-24
Also published as: JP3221946U

Abstract

The utility model provides a heat treatment furnace which can easily cool the processed object. The heat treatment furnace (10) comprises: a container-shaped pressure vessel (12); a heat insulator (16) disposed in the internal space (14) of the pressure vessel (12), and having a heat insulating main body (52) and a heat insulating cover (54); a heater (20) disposed in the internal space (18) of the heat insulating body (52); a sealed box (24) which is disposed in the internal space (18) of the heat insulation body (52) and accommodates an object to be treated (22); a fan (26) that is disposed in the internal space (14) of the pressure vessel (12) and circulates gas; a cooler (28) that cools gas that circulates in the internal space (14) of the pressure vessel (12); and an air guide path (30) which is an air duct connecting the periphery of the fan (26) and the vicinity of the heat insulating cover (54).

Description

Heat treatment furnace

Technical Field

The utility model relates to a heat treatment furnace.

Background

Conventionally, a material to be treated including a metal, a magnetic material, or the like is put into a heat treatment furnace and heat-treated in a vacuum or pressurized atmosphere. 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. By shortening the treatment time of the object to be treated, the operation time of the heat treatment furnace can be shortened, and the heat treatment efficiency is improved.

[ Prior art documents ]

[ patent document ]

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

SUMMERY OF THE UTILITY MODEL

[ problem to be solved by the utility model ]

However, even if the gas is cooled by the cooling fins, the cooling capacity does not increase unless the gas is efficiently blown onto the object to be processed. For example, if the gas cooled by the cooling fins is not blown on the object to be processed by the shortest route, the temperature of the gas may be increased. If the temperature of the gas rises, the object to be processed cannot be cooled efficiently. The heat treatment furnace of patent document 1 circulates only gas, and there is a possibility that the object to be treated cannot be cooled efficiently.

Accordingly, an object of the present invention is to provide a heat treatment furnace which can easily cool an object to be treated.

[ means for solving problems ]

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

The utility model discloses a heat treatment furnace includes: a container-shaped pressure vessel; a heat insulator disposed in an internal space of the pressure vessel and having a heat insulating body and a heat insulating cover; a heater disposed in an inner space of the heat insulating body; a sealing box (light box) disposed in the inner space of the heat insulation body and used for accommodating the processed object; a fan disposed in an internal space of the pressure vessel and circulating gas; a cooler that cools gas circulating in an internal space of the pressure vessel; and an air guide path which is an air duct connecting the periphery of the fan and the vicinity of the heat insulation cover.

[ effects of the utility model ]

According to the present invention, the gas cooled by the cooler is transported to the vicinity of the heat insulating cover through the air guide path, and thus the cooled gas is transported into the sealed box. Since the cooled gas is blown onto the object to be treated, the cooling efficiency of the object to be treated is good.

Drawings

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

FIG. 2 is a side sectional view of the heat treatment furnace.

FIG. 3 is a plan sectional view of the heat treatment furnace.

Fig. 4 is a graph showing a temperature change during heat treatment of the object to be treated.

FIG. 5 is a view showing the structure of a heat treatment furnace including a buffer tank.

FIG. 6 is a side sectional view of the heat treatment furnace.

FIG. 7 is a plan sectional view of the heat treatment furnace.

[ description of symbols ]

10. 96: heat treatment furnace

12: pressure vessel

14. 18, 32: inner space

16: heat insulator

20: heating device

22: object to be treated

24: sealing box

26. 108: fan with cooling device

28: cooling device

30. 102: air guide path

34: pump and method of operating the same

36: a first gas source

38: a first lead-in pipe

40: second gas source

42: second inlet pipe

44: container body

46: container lid

48: inner wall

50: outer wall

52: heat insulation body

54: heat insulation cover

56: sealing box body

58: sealed box cover

60: motor with a stator having a stator core

62: cooling pipe

64: first box

66. 104: catheter tube

68: second box

70. 106: guide plate

72: air suction inlet

74: exhaust port

76: gap

78: opening of the container

80: first exhaust pipe

82: second exhaust pipe

84. 86, 92, 94, 100: valve with a valve body

88: wax pot

90: wax catcher

98: buffer tank

Detailed Description

The heat treatment furnace of the present invention will be described with reference to the 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.

[ 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 an internal space 14 of the pressure vessel 12, a heater 20 disposed in an internal space 18 of the insulator 16, a sealed box (inner case) 24 in which an object to be treated 22 is accommodated, a fan 26 for circulating gas, a cooler 28 for cooling gas, and an air guide path 30 serving as an air passage for gas.

Further, the heat treatment furnace 10 includes: a pump 34 for depressurizing the internal space 14 of the pressure vessel 12 and the internal space 32 of the seal box 24, a first gas source 36 for introducing gas into the internal space 14 of the pressure vessel 12, a first introduction pipe 38 for connecting the pressure vessel 12 to the first gas source 36, a second gas source 40 for introducing gas into the internal space 32 of the seal box 24, and a second introduction pipe 42 for connecting the seal box 24 to the second gas source 40.

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 ]

The pressure vessel 12 includes a vessel body 44 and a vessel lid 46. The container body 44 has a cylindrical shape. The container lid 46 opens and closes both ends of the container body 44. When both ends of the container body 44 are closed by the container lid 46, the internal space 14 of the pressure container 12 becomes a closed 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 is of a dual construction including an inner wall 48 and an outer wall 50. The pipe through which the cooling water flows is disposed between the inner wall 48 and the outer wall 50. The gas contacts the inner wall 48, whereby the gas is cooled. In addition to being cooled by the cooler 28, the gas is also cooled by the pressure vessel 12.

[ Heat insulator ]

The insulator 16 is disposed in the internal space 14 of the pressure vessel 12. The insulator 16 includes an insulator body 52 and an insulator cover 54. The insulating body 52 has a cylindrical shape. The heat insulating cover 54 opens and closes both ends of the heat insulating body 52. As shown in fig. 2 and 3, an opening/closing device (not shown) for the heat insulating cover 54 is provided so that the heat insulating cover 54 can be opened and closed in a state where the container cover 46 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 an internal space 18 formed by the heat insulator 16. The heater 20 may be a rod heater (rod heater) made of graphite. The heater 20 is formed in parallel with the seal box 24. The heater 20 generates heat by supplying three-phase ac power from, for example, electrodes (not shown). Both ends of the heat insulating body 52 are closed by the heat insulating cover 54, thereby preventing heat of the heater 20 from being radiated from the inner space 18 of the heat insulator 16 to the outside.

[ sealed case ]

A sealed box 24 is disposed in the internal space 18 formed by 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, a sealed box cover 58 is attached to the heat insulating cover 54, and the heat insulating cover 54 is opened and closed together with the sealed box cover 58. The both ends of the seal case body 56 are closed by the seal case lid 58, whereby the internal space 32 of the seal case 24 is sealed. Further, a guide rail or the like for moving the seal box 24 into and out of the internal space 18 may be included in a state where the container lid 46 and the heat insulating lid 54 are opened.

[ treated article ]

The object 22 to be treated is disposed in the internal space 32 of the sealed casing 24. The sealed box 24 includes a shelf (not shown) for disposing the object 22. 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 released to the outside of the seal box. Contamination of the inner wall 48 of the pressure vessel 12, the insulator 16, the heater 20, the fan 26, the cooler 28, and the like can be prevented.

[ Fan ]

The fan 26 is mounted on a container cover 46 on one side. The motor 60 is attached to the outside of the container cover 46, and the fan 26 is rotated by the motor 60. The air in the internal space 14 of the pressure vessel 12 and the internal space 32 of the seal box 24 is circulated by the fan 26. The circulation of the gas will be described later.

[ cooler ]

The cooler 28 is disposed in the interior space 14 of the pressure vessel 12. The cooler 28 is a water-cooled cooler, and includes cooling pipes 62 and cooling fins. The cooling pipe 62 penetrates the pressure vessel 12 from the outside of the pressure vessel 12, and cooling water flows through the cooling pipe 62. The gas is cooled by cooling water as it passes through the cooler 28. The cooled gas cools the object 22 and the heat insulator 16. The cooling pipe 62 may be connected to a heat exchanger outside the pressure vessel 12, and the cooling water may be cooled by the heat exchanger and then again introduced into the cooler 28. The cooling fins are attached to the cooling pipe 62. The cooling efficiency of the gas is improved by the cooling fins.

[ air guide route ]

The air guide path 30 is an air duct that efficiently guides the air cooled by the cooler 28 to the hermetic container 24. As shown in fig. 2 and 3, air guide path 30 is formed by first box 64 disposed on the outer periphery of fan 26, duct 66 disposed from first box 64 to the vicinity of heat insulating cover 54, second box 68 disposed on the outer periphery of cooler 28, and guide plate 70 for guiding the gas to second box 68.

The fan 26 draws the air cooled by the cooler 28 into the first box 64. The gas drawn into the first box 64 is blown against the inner surface of the first box 64 and flows into the conduit 66 (fig. 3). The duct 66 is a tubular body including an intake port 72 and an exhaust port 74. The suction port 72 of the duct 66 is provided in the first box 64, and the gas is guided from the first box 64 toward the duct 66. The exhaust port 74 of the conduit 66 is disposed adjacent the insulating cover 54. The exhaust port 74 of the conduit 66 opens toward the heat insulating cover 54, and the gas flowing in the conduit 66 is formed to proceed toward the heat insulating cover 54. When the heat insulating cover 54 is opened, the gas flowing through the duct 66 enters the sealed box 24 opened together with the heat insulator 16.

The first case 64 is connected to the second case 68, and their inner spaces are connected to each other. The gas cooled by the cooler 28 is directly sucked into the inner space of the first case 64. The guide plate 70 is mounted to the inner wall 48 of the pressure vessel 12. The gas passing through the gap 76 between the inner wall 48 of the pressure vessel 12 and the insulator 16 is blown against the guide plate 70 (fig. 3) and is guided to the opening 78 of the second box 68. In the second box 68 there is a cooler 28, the gas being cooled. The gas passing through the gap 76 between the inner wall 48 of the pressure vessel 12 and the insulator 16 passes through the cooler 28, the fan 26, the duct 66, and is directed to the interior space 32 of the seal box 24. The gas is blown onto the object 22 in the sealed box 24, discharged from the sealed box 24, and then passes through the gap 76 between the inner wall 48 of the pressure vessel 12 and the heat insulator 16 again.

[ Pump ]

The pump 34 is a device for evacuating the internal space 14 of the pressure vessel 12 and the internal space 32 of the seal box 24 and reducing the pressure in the internal space 14 and the internal space 32. Further, by depressurizing the internal space 14 of the pressure vessel 12, the internal space 18 of the heat insulator 16 is also depressurized. As the kind of the pump 34, there are listed: dry pumps, turbo-molecular pumps, oil rotary pumps, oil diffusion pumps, and the like.

The internal space 14 of the pressure vessel 12 is connected to the pump 34 by a first exhaust pipe 80, and the internal space 32 of the seal box 24 is connected to the pump 34 by a second exhaust pipe 82. A valve 84 is disposed in the middle of the first exhaust pipe 80, and when the valve 84 is opened, exhaust is possible, and when the valve 84 is closed, exhaust is not possible.

A valve 86, a wax pot 88, and a wax trap 90 are provided in the second exhaust pipe 82. The internal space 32 of the seal box 24 can be exhausted or stopped by opening and closing the valve 86. The wax pot 88 and the wax trap 90 accumulate the adhesive discharged from the object 22. The adhesive does not reach the pump 34, and contamination and malfunction of the pump 34 can be prevented.

[ gas source ]

The first gas source 36 stores, generates, or both the gas introduced into the interior space 14 of the pressure vessel 12. The second gas source 40 stores, generates, or both the gas introduced into the interior space 32 of the seal box 24. The gas of the first gas source 36 is nitrogen or argon, etc., and the gas of the second gas source 40 is nitrogen, argon, hydrogen, carbon monoxide, helium, methane, etc. In fig. 1, the number of the first gas source 36 and the second gas source 40 is one, but if the number of the gas species increases, the number of the first gas source 36 and the second gas source 40 increases according to the number of the gas species. The

interior space

14, 32 can be brought into a pressurized state by introducing gas from the first gas source 36, the second gas source 40, into the interior space.

The interior space 14 of the pressure vessel 12 is connected to a first gas source 36 by a first inlet conduit 38, and the interior space 32 of the seal box 24 is connected to a second gas source 40 by a second inlet conduit 42. The first introduction pipe 38 and the second introduction pipe 42 are provided with a valve 92 and a valve 94. Valve 92 controls the flow of gas from first gas source 36 toward pressure vessel 12 and valve 94 controls the flow of gas from second gas source 40 toward seal box 24.

[ others ]

The heat treatment furnace 10 of the present application includes: a thermometer (not shown) for measuring the temperature of the internal space 18 of the heat insulator 16, 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 pump 34, the valve 84, and the valve 86 are controlled during pressure reduction, and the

valves

92 and 94 are controlled during pressure increase, in accordance 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 was performed in the following order (1) to (5). The heat treatment described above is an example, and the temperature and the pressure may be different.

(1) Preparation step

The sealed box cover 58, the heat insulating cover 54, and the container cover 46 are opened, and the object 22 is accommodated in the internal space 32 of the sealed box 24, and then the sealed box cover 58, the heat insulating cover 54, and the container cover 46 are closed, thereby turning to the state shown in fig. 1. Further, the internal space 14 of the pressure vessel 12 and the internal space 32 of the seal box 24 are controlled to have predetermined pressures by discharging air with the pump 34.

(2) Step of temperature rise

As shown in fig. 4, the current is caused to flow into the heater 20, thereby raising 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 is further heated. At this time, the

valves

92 and 94 may be opened to introduce the first gas and the second gas into the internal space 14 of the pressure vessel 12 and the internal space 32 of the seal box 24, respectively, and pressurize the

internal spaces

14 and 32.

(3) Degreasing step

The current flowing into the heater 20 is increased to raise the temperature of the internal space 18 of the heat insulator 16 as compared with the temperature raising step, and the object 22 to be treated is degreased. At this time, the

valves

84 and 86 are opened, and the pump 34 is started to reduce the pressure in the

internal spaces

14 and 32. The binder generated from the object 22 when the object 22 is degreased is accumulated in the wax tank 88 and the wax trap 90. At this time, the

valves

92 and 94 are closed, and the introduction of the first gas and the second gas is stopped.

(4) Heat treatment step

After the degreasing of the object 22 is completed, the temperature of the object 22 is raised by increasing the current flowing into the heater 20, and the heat treatment is performed. For example, the object 22 is sintered at about 500 to 2400 ℃. The pressure of the

interior space

14, 32 is controlled by the heat treatment process. When the pressurization is performed, the

valves

84 and 86 are closed to stop the pump 34, and the

valves

92 and 94 are opened to introduce the first gas and the second gas into the

internal spaces

14 and 32. When the pressure is reduced, the

valves

84 and 86 are opened to drive the pump 34, and the

valves

92 and 94 are closed to stop the introduction of the first gas and the second gas into the

internal spaces

14 and 32.

(5) Step of Cooling

After the object 22 is heat-treated, the object 22 is cooled as follows. The

valves

84, 86 are closed to bring the pump 34 to a stop state, and the valve 92 is opened to introduce the first gas into the interior space 14 of the pressure vessel 12. At this time, the internal space 14 of the pressure vessel 12 is brought into a pressurized state. For example, the first gas is introduced into the internal space 14 of the pressure vessel 12 so as to change from a vacuum state to about 0.6 MpaG.

Simultaneously with the introduction of the first gas into the internal space 14 of the pressure vessel 12, as shown in fig. 2 and 3, the heat insulating cover 54 and the sealed case cover 58 are opened with the case cover 46 closed, and the fan 26 is rotated. The gas is circulated by the rotation of the fan 26. As indicated by arrow w in fig. 2 and 3, the gas is discharged from the sealed box 24 to the outside of the sealed box 24, passes through the gap 76 between the inner wall 48 of the pressure vessel 12 and the heat insulator 16, the cooler 28, the fan 26, and the duct 66, and enters the sealed box 24 again. The gas is blown onto the object 22 in the seal box 24 to cool the object 22. The gas heated by the object 22 is cooled by the cooler 28.

Simultaneously with the introduction of the first gas into the interior space 14 of the pressure vessel 12, the valve 92 may also be opened to introduce the second gas into the interior space 32 of the seal box 24. As shown in fig. 2 and 3, in the cooling step, the sealed cover 58 is opened, and the first gas and the second gas are mixed and circulated. In this case, the first gas and the second gas are preferably the same kind of gas.

As described above, the gas cooled by the air guide passage 30 can be guided to the internal space 32 of the seal box 24 by the shortest route. Since the gas can be blown onto the object 22 before the temperature is raised, the cooling efficiency of the object 22 becomes good. Since the cooling time of the object 22 to be treated is shortened, the cycle time of the heat treatment furnace 10 is shortened.

[ embodiment 2]

As in the heat treatment furnace 96 of fig. 5, a buffer tank 98 may be provided in the middle of the first introduction pipe 38. The gas is temporarily stored in the buffer tank 98. By storing the gas in the buffer tank 98, the gas can be introduced into the internal space 14 of the pressure vessel 12 at a time. The time during which the internal space 14 of the pressure vessel 12 can be brought into a pressurized state by the gas can be shortened. The capacity of the buffer tank 98 is set to be two times or more (ten atmospheres) of the internal space 14 of the pressure vessel 12, for example, about two times to four times. By making the capacity of the buffer tank 98 larger than the capacity of the internal space 14 of the pressure vessel 12, the gas can be introduced into the internal space 14 of the pressure vessel 12 at once.

The first introduction pipe 38 from the first gas source 36 to the buffer tank 98 has a bore of, for example, 5mm to 10 mm. The gas is supplied from the first gas source 36 toward the buffer tank 98 at the same flow rate as before, and is accumulated in the buffer tank 98. The diameter of the first introduction pipe 38 between the pressure vessel 12 and the buffer tank 98 is made larger than the diameter of the first introduction pipe 38 from the first gas source 36 to the buffer tank 98. This is to introduce the gas from the buffer tank 98 into the internal space 14 of the pressure vessel 12 at a time. For example, the diameter of the first introduction pipe 38 between the pressure vessel 12 and the buffer tank 98 is about 20mm to 100 mm. The pressure vessel 12 can be pressurized by filling the pressure vessel 12 with a gas at a higher flow rate from the buffer tank 98 to the pressure vessel 12 than before.

The gas is introduced into the pressure vessel 12 from the buffer tank 98 at a time during the cooling step of the treatment object 22, and the valve 100 is opened during the cooling step. In other steps, the valve 100 may be controlled to reduce the flow rate of the gas or set the flow rate to 0 to store the gas in the buffer tank 98. Before the buffer tank 98 is filled with gas, gas is supplied from the first gas source 36 toward the buffer tank 98 regardless of the pressure state of the pressure vessel 12.

By providing the buffer tank 98, the gas can be introduced into the internal space 14 of the pressure vessel 12 at a time. The internal space 14 of the pressure vessel 12 can be brought into a pressurized state in a short time. Since the gas can be introduced into the internal space 14 of the pressure vessel 12 in a short time, the internal space 14 of the pressure vessel 12 can be filled with the gas for cooling the object 22 to be processed. The cooling time of the object 22 to be treated can be shortened.

[ embodiment 3]

The air guide path 102 provided in the internal space 14 of the pressure vessel 12 in fig. 6 and 7 is formed as follows: a conduit 104 connects the inner wall 48 of the pressure vessel 12 to the gap 76 of the insulation 16 and the first box 64, and a guide plate 106 guides the gas from the vicinity of the insulation cover 54 to the second box 68. Unlike embodiment 1, the fan 108 conveys the gas from the duct 104 toward the cooler 28. As indicated by arrows w in fig. 6 and 7, the gas flows from the internal space 32 of the sealed box 24 through the gap 76 between the inner wall 48 of the pressure vessel 12 and the heat insulator 16, and then flows through the duct 104. From the duct 104, through the fan 108, through the cooler 28, and into the interior space 32 of the seal box 24.

[ embodiment 4]

The flow of gas may be reversed by changing the structures of the fan 26 and the fan 108 described in the above embodiments.

[ embodiment 5]

Cooling fins may be attached to the inner wall 48 of the pressure vessel 12. The heat of the gas is conducted from the fins to the cooling water passing between the inner wall 48 and the outer wall 50. By cooling the gas, the cooling efficiency of the object 22 becomes good.

(first embodiment) the heat treatment furnace of the first embodiment includes: a container-shaped pressure vessel; a heat insulator disposed in an internal space of the pressure vessel and having a heat insulating body and a heat insulating cover; a heater disposed in an inner space of the heat insulating body; a sealed box disposed in the inner space of the heat insulation body and accommodating the processed object; a fan disposed in an internal space of the pressure vessel and circulating gas; a cooler that cools gas circulating in an internal space of the pressure vessel; and an air guide path which is an air duct connecting the periphery of the fan and the vicinity of the heat insulation cover.

According to the heat treatment furnace described in the first embodiment, the gas cooled by the cooler is sent to the vicinity of the heat insulating cover through the air guide path, and therefore the cooled gas is sent to the sealed box. Since the cooled gas is blown onto the object to be treated, the cooling efficiency of the object to be treated is good.

(second embodiment) the air guide path may include: a first case disposed on an outer periphery of the fan; and a duct having an air inlet provided in the first case and an air outlet disposed in the vicinity of the heat insulating cover.

According to the heat treatment furnace described in the second embodiment, the gas can be directly sent from the fan to the vicinity of the heat insulating cover through the duct. The cooled gas may be transported into a sealed box before warming.

(third embodiment) the air guide path may include: a second case disposed on an outer periphery of the cooler; and a guide plate for conveying gas from between the inner wall of the pressure vessel and the heat insulator toward the interior of the second case; and the first cartridge is connected to the second cartridge.

According to the heat treatment furnace described in the third embodiment, the heated gas after cooling the object to be treated is guided to the cooler located in the second cassette, and then immediately sent to the fan, and the gas can be sent from the fan to the vicinity of the heat insulating cover via the duct. The cooled gas can be transported into the sealed box by cooling the gas until the gas is transported to the vicinity of the heat insulating cover without bringing the gas into contact with the object to raise the temperature of the gas.

(fourth embodiment) the pressure vessel may also include an inner wall and an outer wall, and the cooling water flows between the inner wall and the outer wall.

According to the heat treatment furnace described in the fourth embodiment, the gas may be cooled by contacting the gas with the inner wall of the pressure vessel. Since the gas can be cooled in addition to the cooler, the cooling efficiency of the gas is good.

(fifth embodiment) the cooler may be a water-cooled cooler.

According to the heat treatment furnace described in the fifth embodiment, the cooling capacity of the gas is increased by the water-cooled cooler.

(sixth embodiment) may also include: a first gas source that introduces a gas into the interior space of the pressure vessel; a first inlet pipe connecting the pressure vessel with a first gas source; and a buffer tank provided in the middle of the first introduction pipe and storing the gas supplied from the first gas source.

According to the heat treatment furnace described in the sixth embodiment, the gas is stored in the buffer tank, so that the gas can be introduced into the pressure vessel at once. The pressure vessel can be filled with gas in a short time, and the cooling efficiency is improved.

The present invention is also applicable to embodiments to which various improvements, modifications, and changes have been made based on the knowledge of those skilled in the art without departing from the scope of the present invention. The embodiments described are not independent embodiments, but 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 characterized by comprising:

a container-shaped pressure vessel;

a heat insulator disposed in an internal space of the pressure vessel and having a heat insulating body and a heat insulating cover;

a heater disposed in an inner space of the heat insulating body;

a sealed box disposed in the inner space of the heat insulation body and accommodating the processed object;

a fan disposed in an internal space of the pressure vessel and circulating gas;

a cooler that cools gas circulating in an internal space of the pressure vessel; and

and an air guide path which is an air duct connecting the periphery of the fan and the vicinity of the heat insulation cover.

2. The heat treatment furnace according to claim 1,

the air guide path is provided with:

a first case disposed on an outer periphery of the fan; and

and a duct having an air inlet provided in the first case and an air outlet disposed in the vicinity of the heat insulating cover.

3. The heat treatment furnace according to claim 2,

the air guide path is provided with:

a second case disposed on an outer periphery of the cooler; and

a guide plate for conveying a gas from between an inner wall of the pressure vessel and the heat insulator toward an interior of the second case; and is

The first cartridge is connected to the second cartridge.

4. The heat treatment furnace according to any one of claims 1 to 3,

the pressure vessel comprises an inner wall and an outer wall, and cooling water flows between the inner wall and the outer wall.

5. The heat treatment furnace according to any one of claims 1 to 3,

the cooler is a water-cooled cooler.

6. The heat treatment furnace according to claim 4,

the cooler is a water-cooled cooler.

7. The heat treatment furnace according to any one of claims 1 to 3, characterized by comprising:

a first gas source that introduces a gas into the interior space of the pressure vessel;

a first inlet pipe connecting the pressure vessel with the first gas source; and

and a buffer tank provided in the middle of the first introduction pipe and storing the gas supplied from the first gas source.

8. The heat treatment furnace according to claim 4, characterized by comprising:

9. The heat treatment furnace according to claim 5, characterized by comprising:

10. The heat treatment furnace according to claim 6, characterized by comprising: