CN210596169U - Heat treatment furnace - Google Patents

Abstract

The utility model provides a heat treatment furnace which can lead a large amount of gas into a pressure container in a short time. The heat treatment furnace (10) comprises: a container-shaped pressure vessel (12); a heat insulator (16) disposed in an internal space (14) of the pressure vessel (12); a heater (20) disposed in an internal space (18) formed by the heat insulator (16); a sealed box (24) which is disposed in an internal space (18) formed by the heat insulator (16) and which accommodates an object to be treated (22); a pump (28) that depressurizes the internal space (14) of the pressure vessel (12) and the internal space (26) of the seal box (24); a first gas source (30) for introducing a first gas into the interior space (14) of the pressure vessel (12); a first inlet pipe (32) connecting the pressure vessel (12) to a first gas source (30); and a buffer tank (34) which is provided in the middle of the first introduction pipe (32) and stores the first gas.

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 cooling fins are provided, the cooling capacity does not become high if the amount of gas contacting the cooling fins is small. For example, if it takes time to change from a vacuum state to a pressurized state, it takes time to increase the cooling capacity of the heat treatment furnace. Therefore, the heat treatment furnace of patent document 1 may not cool the object to be treated in a short time.

Accordingly, an object of the present invention is to provide a heat treatment furnace capable of introducing a large amount of gas into a pressure vessel in a short time.

[ 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; a heater disposed in an internal space formed by the heat insulator; a sealed box (light box) disposed in the inner space formed by the heat insulator and accommodating the object to be processed; a pump for depressurizing an internal space of the pressure vessel and an internal space of the seal box; a first gas source to introduce a first 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 first gas.

[ effects of the utility model ]

According to the utility model discloses, through depositing first gas at the buffer tank, can be in the short time with leading-in to pressure vessel's inner space in a large number of first gas. The internal space of the pressure vessel can be filled with the first gas in a short time to become a pressurized state. When the object to be treated is cooled, the cooling efficiency is improved by a large amount of the first gas.

Drawings

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

Fig. 2 is a view showing a structure of the heat treatment furnace of the present invention when cooling the object to be treated.

Fig. 3 is a graph showing a temperature change during heat treatment of an object to be treated.

Fig. 4 is a view showing another configuration of the heat treatment furnace in which a plurality of first introduction pipes are provided.

Fig. 5 is a diagram showing a structure of a heat treatment furnace in which a plurality of buffer tanks are provided.

Fig. 6 is a view showing the structure of a heat treatment furnace in which a buffer tank is provided in the second introduction pipe.

[ description of symbols ]

10. 80, 82, 90: heat treatment furnace

12: pressure vessel

14. 18, 26: inner space

16: heat insulator

20: heating device

22: object to be treated

24: sealing box

28: pump and method of operating the same

30: a first gas source

32: a first lead-in pipe

34. 92: buffer tank

36: second gas source

38: second inlet pipe

40: container body

42: container lid

44: heat insulation body

46: heat insulation cover

48: sealing box body

50: sealed box cover

52: first exhaust pipe

54: second exhaust pipe

56. 58, 64, 66, 68, 94: valve with a valve body

60: wax pot

62: wax catcher

70: fan with cooling device

72: cooling device

74: guide piece

76: motor with a stator having a stator core

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 box) 24 in which an object to be treated 22 is accommodated, a pump 28 for depressurizing the internal space 14 of the pressure vessel 12 and an internal space 26 of the sealed box 24, a first gas source 30 for introducing a first gas into the internal space 14 of the pressure vessel 12, a first introduction pipe 32 for connecting the pressure vessel 12 and the first gas source 30, and a buffer tank 34 provided in the middle of the first introduction pipe 32.

Further, the heat treatment furnace 10 includes: a second gas source 36 for introducing a second gas into the interior space 26 of the seal box 24, and a second introduction tube 38 for connecting the seal box 24 to the second gas source 36.

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 40 and a vessel lid 42. The container body 40 has a cylindrical shape. The container lid 42 opens and closes both ends of the container body 40. When both ends of the container body 40 are closed by the container lid 42, 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. In the description of the present application, the reduced pressure means a state lower than the atmospheric pressure (the pressure of the sea surface), and includes vacuum.

[ Heat insulator ]

The insulator 16 is disposed in the internal space 14 of the pressure vessel 12. The insulator 16 includes an insulator body 44 and an insulator cover 46. The insulating body 44 has a cylindrical shape. The heat insulating cover 46 opens and closes both ends of the heat insulating body 44. As shown in fig. 2, the heat insulating cover 46 includes an opening/closing device (not shown) for opening/closing the heat insulating cover 46 so that the heat insulating cover 46 can be opened/closed in a state where the container lid 42 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 electrodes (not shown). Both ends of the heat insulating body 44 are closed by the heat insulating cover 46, 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 48 and a seal box cover 50. The seal box body 48 is cylindrical. The seal case cover 50 opens and closes both ends of the seal case body 48. As shown in fig. 2, the sealing cover 50 includes a driving device (not shown) for driving the sealing cover 50 so that the sealing cover 50 can be opened and closed in a state where the cover 42 is closed. The both ends of the seal case body 48 are closed by the seal case lid 50, whereby the internal space 26 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 42 and the heat insulating lid 46 are opened.

[ treated article ]

The object 22 to be treated is disposed in the internal space 26 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 when the object to be treated 22 is degreased can be prevented from being released to the outside of the seal box 24. The inner wall of the pressure vessel 12, the heat insulator 16, the heater 20, and the like can be prevented from being contaminated.

[ Pump ]

The pump 28 is a device for evacuating the internal space 14 of the pressure vessel 12 and the internal space 26 of the seal box 24 and reducing the pressure in the internal space 14 and the internal space 26. 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 28, 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 28 via a first exhaust pipe 52, and the internal space 26 of the seal box 24 is connected to the pump 28 via a second exhaust pipe 54. A valve 56 is disposed in the middle of the first exhaust pipe 52, and if the valve 56 is opened, exhaust is possible, and if the valve 56 is closed, exhaust is not possible.

A valve 58, a wax pot 60, and a wax trap 62 are provided in the second exhaust pipe 54. The internal space 26 of the seal box 24 can be exhausted or stopped by opening and closing the valve 58. The wax pot 60 and the wax trap 62 accumulate the adhesive discharged from the object 22. The adhesive does not reach the pump 28, preventing contamination and malfunction of the pump 28.

[ gas source ]

The first gas source 30 stores, generates, or both the first gas introduced into the interior space 14 of the pressure vessel 12. The second gas source 36 stores, generates, or both the second gas introduced into the interior space 26 of the seal box 24. The first gas is nitrogen or argon, and the second gas is nitrogen, argon, hydrogen, carbon monoxide, helium, methane, and the like. In fig. 1, the number of the first gas source 30 and the second gas source 36 is one, but if the number of the gas species increases, the number of the first gas source 30 and the second gas source 36 increases according to the number of the gas species. The pressurized state can be achieved by introducing a first gas and a second gas into each of the interior spaces 14, 26.

The interior space 14 of the pressure vessel 12 is connected to a first gas source 30 by a first inlet conduit 32, and the interior space 26 of the seal box 24 is connected to a second gas source 36 by a second inlet conduit 38. The first introduction pipe 32 and the second introduction pipe 38 are provided with a valve 64, a valve 66, and a valve 68. Valve 64 controls the flow of the first gas from gas source 30 toward surge tank 34, valve 66 controls the flow of the first gas from surge tank 34 toward pressure vessel 12, and valve 68 controls the flow of the second gas from second gas source 36 toward seal box 24.

[ buffer tank ]

A buffer tank 34 is provided in the middle of the first introduction pipe 32. The first gas is temporarily stored in the buffer tank 34. By storing the first gas in the buffer tank 34, the first gas can be introduced into the interior space 14 of the pressure vessel 12 at a single time. The time during which the internal space 14 of the pressure vessel 12 can be brought into a pressurized state by the first gas can be shortened. The capacity of the buffer tank 34 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 34 larger than the capacity of the internal space 14 of the pressure vessel 12, the first gas can be introduced into the internal space 14 of the pressure vessel 12 at a time.

[ first introducing tube ]

The first introduction pipe 32 from the first gas source 30 to the buffer tank 34 has a bore of, for example, 5mm to 10 mm. The first gas is supplied from the first gas source 30 toward the buffer tank 34 at the same flow rate as before, and is stored in the buffer tank 34. The diameter of the first introduction pipe 32 between the pressure vessel 12 and the buffer tank 34 is made larger than the diameter of the first introduction pipe 32 between the first gas source 30 and the buffer tank 34. This is to introduce the first gas from the buffer tank 34 into the internal space 14 of the pressure vessel 12 at a time. For example, the diameter of the first introduction pipe 32 between the pressure vessel 12 and the buffer tank 34 is about 20mm to 100 mm. The pressure vessel 12 can be pressurized by filling the pressure vessel 12 with the first gas with a gas flow rate larger than that before from the buffer tank 34.

The first gas is introduced into the pressure vessel 12 from the buffer tank 34 at a time during the cooling step of the treatment object 22, and the valve 66 is opened during the cooling step. In other steps, the valve 66 may be controlled to reduce the flow rate of the first gas to 0, or the first gas may be stored in the buffer tank 34. Before the buffer tank 34 is filled with the first gas, the first gas is supplied from the first gas source 30 toward the buffer tank 34 regardless of the pressure state of the pressure vessel 12.

[ others ]

The heat treatment furnace 10 of the present application includes: a fan 70, a cooler 72, and a guide 74. The fan 70 is attached to one of the container covers 42, and is rotated by a motor 76 attached to the container cover 42. As indicated by arrow Y in fig. 2, the fan 70 circulates the gas in the internal space 14 of the pressure vessel 12 and the internal space 26 of the seal box 24. The cooler 72 cools the circulating gas, and the guide 74 guides the gas to the cooler 72. As the cooler 72, a heat exchanger can be cited. The gas is cooled by the cooler 72, and the cooled gas cools the object 22 to be processed, the heater 20, and the heat insulator 16.

Further, the heat treatment furnace 10 of the present application includes: a thermometer (not shown) for measuring the temperature of the internal space 26 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 28, the valve 56, and the valve 58 are controlled in accordance with the pressure measured by the pressure gauge when pressure reduction is performed, and the valve 64, the valve 66, and the valve 68 are controlled when pressure increase is performed.

[ 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 object 22 to be treated is accommodated in the internal space 26 of the sealed box 24, and the sealed box cover 50, the heat insulating cover 46 and the container cover 42 are closed to be in the state shown in fig. 1. Further, the internal space 14 of the pressure vessel 12 and the internal space 26 of the seal box 24 are controlled to have predetermined pressures by discharging air by the pump 28.

(2) Step of temperature rise

As shown in fig. 3, 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 64, 66, and 68 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 26 of the seal box 24, respectively, and pressurize the internal spaces 14 and 26.

(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 56 and 58 are opened, and the pump 28 is started to reduce the pressure in the internal spaces 14 and 26. The binder generated from the object 22 when the object 22 is degreased is accumulated in the wax tank 60 and the wax trap 62. At this time, the valves 66 and 68 are closed, and the introduction of the first gas and the second gas is stopped. The valve 64 is opened until the first gas is accumulated in the buffer tank 34, and the valve 64 is closed when the first gas is accumulated in the buffer tank 34.

(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 1500 to 1600 ℃. The pressure of the interior spaces 14, 26 is controlled by the method of heat treatment. When the pressurization is performed, the valves 56 and 58 are closed to stop the pump 28, and the valves 64, 66 and 68 are opened to introduce the first gas and the second gas into the internal space 14 and the internal space 26. When the pressure is reduced, the valves 56 and 58 are opened to drive the pump 28, and the valves 66 and 68 are closed to stop the introduction of the first gas and the second gas into the internal spaces 14 and 26.

(5) Step of Cooling

After the object 22 is heat-treated, the object 22 is cooled as follows. The valves 56, 58 are closed to bring the pump 28 to a stop state and the valves 64, 66 are opened to introduce the first gas into the interior space 14 of the pressure vessel 12. At this time, the first gas stored in the buffer tank 34 is introduced to pressurize the internal space 14 of the pressure vessel 12. For example, the first gas is introduced into the internal space 14 of the pressure vessel 12 so that the vacuum state becomes about 0.6MpaG within about 30 seconds to 2 minutes. The interior space 14 of the pressure vessel 12 is filled with a first gas. Simultaneously with the introduction of the first gas into the internal space 14 of the pressure vessel 12, as shown in fig. 2, the heat insulating cover 46 and the sealed case cover 50 are opened with the case cover 42 closed, and the fan 70 is rotated. The first gas circulates as indicated by arrow Y in fig. 2. The first gas is cooled by the cooler 72, and the cooled first gas cools the object 22. The internal space 14 is filled with the first gas for a short time, and thus the cooling efficiency is improved for a short time.

While the first gas is introduced into the interior space 14 of the pressure vessel 12, the valve 68 may also be opened to introduce the second gas into the interior space 26 of the seal box 24. As shown in fig. 2, the hermetic container cover 50 is opened in the cooling step, and the first gas is mixed with the second gas to be circulated. In this case, the first gas and the second gas are preferably the same kind of gas.

As described above, the present application may introduce a first gas into the interior space 14 of the pressure vessel 12. The internal space 14 of the pressure vessel 12 can be brought into a pressurized state in a short time. Since the first gas can be introduced into the internal space 14 of the pressure vessel 12 in a short time, the cooling time of the object 22 to be treated can be shortened, and the cycle time of the heat treatment furnace 10 can be shortened.

[ embodiment 2]

As in the heat treatment furnace 80 shown in fig. 4, a plurality of first introduction pipes 32 may be provided from the buffer tank 34 to the pressure vessel 12. By increasing the number of the first introduction pipes 32, the amount of the first gas that can be introduced into the pressure vessel 12 from the buffer tank 34 increases.

[ embodiment 3]

As in the heat treatment furnace 82 of fig. 5, the first gas source 30, the first introduction pipe 32, the buffer tank 34, the valves 64, and the valves 66 may be provided in plural numbers. When the number of the first gas sources 30 and the buffer tanks 34 is increased, the amount of the first gas that can be introduced into the pressure vessel 12 increases, and the pressure vessel 12 can be filled with the first gas in a short time.

[ embodiment 4]

As in the heat treatment furnace 90 shown in fig. 6, a buffer tank 92 may be provided in the middle of the second introduction pipe 38. In the cooling process, the seal case cover 50 is opened, and the first gas and the second gas are mixed inside and outside the seal case 24. Therefore, the first gas and the second gas are introduced into the internal space 14 and the internal space 26 from the buffer tanks 34 and 92 at a time, and thus the pressurized state can be achieved in a short time. The amount of the second gas introduced from the buffer tank 92 into the internal space 26 is controlled by a valve 94 located midway in the second introduction pipe 38.

Similarly to the first introduction pipe 32, the diameter of the second introduction pipe 38 from the buffer tank 92 to the internal space 26 of the seal box 24 is increased. A plurality of second introduction pipes 38 may be provided from the buffer tank 92 to the internal space 26 of the seal box 24. The second gas stored in the buffer tank 92 may be introduced into the inner space 26 at a single time. The second gas source 36, the second introduction pipe 38, the buffer tank 92, the valve 68, and the valve 94 may be provided in plural numbers. The amount of the second gas that can be introduced into the internal space 26 of the seal box 24 can be increased, the second gas can be introduced into the internal space 26 in a short time, and further, the second gas can also flow into the internal space 14 of the pressure vessel 12.

[ embodiment 5]

When the first gas and the second gas circulate in the internal space 14 of the pressure vessel 12, they may circulate in the direction opposite to the direction of the arrow Y shown in fig. 2. That is, the cooling is performed by sending the gas from the fan 70 to the cooler 72, and the cooled gas is sent to the internal space 18 of the heat insulator 16 and the internal space 26 of the seal box 24 to cool the object 22 and the like.

[ embodiment 6]

Cooling fins may be attached to the inner wall of the container cover 42. The heat of the gas is released from the heat radiation fins through the container lid 42. The pressure vessel 12 may be provided with a water-cooled pipe or the like on the outer periphery of the pressure vessel 12 to dissipate heat.

(first embodiment) the heat treatment furnace 10 of the first embodiment 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 formed by the heat insulator 16; a sealed box 24 disposed in the internal space 18 formed by the heat insulator 16 and accommodating the object 22 to be treated; a pump 28 for depressurizing the internal space 14 of the pressure vessel 12 and the internal space 26 of the seal box 24; a first gas source 30 for introducing a first gas into the interior space 14 of the pressure vessel 12; a first inlet pipe 32 connecting the pressure vessel 12 with a first gas source 30; and a buffer tank 34 provided in the middle of the first introduction pipe 32 and storing the first gas.

According to the heat treatment furnace 10 described in the first embodiment, the first gas is stored in the buffer tank 34, so that a large amount of the first 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 first gas to become a pressurized state in a short time. When the object 22 is cooled, the cooling efficiency is improved by a large amount of the first gas.

(second embodiment) the inner diameter of the cross section of the first introduction pipe 32 from the buffer tank 34 to the pressure vessel 12 may be 20mm to 100 mm.

According to the heat treatment furnace 10 described in the second embodiment, since the diameter of the first introduction pipe 32 is larger than the known diameter of the pipe, the first gas can be easily introduced from the buffer tank 34 to the internal space 14 of the pressure vessel 12.

In the third embodiment, the number of the first introduction pipes 32 from the buffer tank 34 to the pressure vessel 12 may be plural.

According to the heat treatment furnace 10 described in the third embodiment, the number of the first introduction pipes 32 is increased, so that the amount of the first gas which can be transported from the buffer tank 34 to the pressure vessel 12 can be increased, and the first gas can be easily introduced into the internal space 14 of the pressure vessel 12.

(fourth embodiment) the buffer tank 34 may be plural.

According to the heat treatment furnace 10 described in the fourth embodiment, the buffer tank 34 is provided in plural, and the amount of the first gas that can be introduced into the pressure vessel 12 at one time can be increased. The first gas is easily introduced into the pressure vessel 12 at a time.

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 (5)

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;

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

a sealed box disposed in an internal space formed by the heat insulator and accommodating an object to be treated;

a pump for depressurizing an internal space of the pressure vessel and an internal space of the seal box;

a first gas source to introduce a first 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 first gas.

2. The heat treatment furnace according to claim 1,

the inner diameter of the cross section of the first introduction pipe from the buffer tank to the pressure vessel is 20mm to 100 mm.

3. The heat treatment furnace according to claim 1 or 2,

the number of first introduction pipes from the buffer tank to the pressure vessel is plural.

4. The heat treatment furnace according to claim 1 or 2,

the buffer tank is in plurality.

5. The heat treatment furnace according to claim 3,

the buffer tank is in plurality.

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