CN113758246A

CN113758246A - Intermittent heat treatment furnace

Info

Publication number: CN113758246A
Application number: CN202110591318.1A
Authority: CN
Inventors: 山口实; 丹羽浩平; 有马和彦; 中村纪久
Original assignee: NGK Insulators Ltd; NGK Kilntech Corp
Current assignee: NGK Insulators Ltd; NGK Kilntech Corp
Priority date: 2020-06-03
Filing date: 2021-05-28
Publication date: 2021-12-07
Also published as: JP6889313B1; TW202212759A; JP2021188869A

Abstract

The invention provides a batch heat treatment furnace, which can inhibit the non-uniformity of the furnace atmosphere. A batch-type heat treatment furnace (10) is provided with: a furnace body (12) having a ceiling wall and a side wall (14); a hearth (20) having an upper surface on which an object to be treated is placed; a plurality of heaters (30) which are arranged in the furnace body, arranged between the side wall and the object to be processed, and arranged along the side wall with intervals in the circumferential direction; and a plurality of gas outlets for supplying an atmosphere gas into the furnace body. The plurality of gas outlets are located between the heaters and the object to be processed in the radial direction in the cylindrical furnace, and are located between the heaters adjacent in the circumferential direction in the cylindrical furnace. The gas blowing direction in which the gas is blown out from the plurality of gas blowing outlets is the direction of the side wall.

Description

Intermittent heat treatment furnace

Technical Field

The technology disclosed in the present specification relates to a batch heat treatment furnace for heat-treating an object to be treated (for example, a laminated ceramic component such as a ceramic capacitor, a ceramic piezoelectric element, or a ceramic resistor).

Background

In order to stabilize the characteristics of the object after heat treatment, it is necessary to make the furnace temperature and the furnace atmosphere uniform during heat treatment. In the batch heat treatment furnace of patent document 1, a plurality of heaters are arranged at intervals in the circumferential direction, and gas outlets are arranged at positions corresponding to the respective heaters. The gas outlet is disposed between the heater and the furnace inner wall surface, and the atmosphere gas from the gas outlet is heated by the heater and supplied into the furnace. Thereby, the temperature in the furnace and the atmosphere in the furnace are uniformized.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2005-77001

Disclosure of Invention

In the batch-type heat treatment furnace of patent document 1, a plurality of gas outlets are arranged at intervals in the circumferential direction, and the atmospheric gas is ejected from each gas outlet toward the center in the furnace. Therefore, the object to be processed placed in the center of the furnace may be: a portion that is blown out from the gas blowout port by the atmosphere gas, and a portion that is not blown out from the gas blowout port by the atmosphere gas. As a result, the following problems occur: at the position where the object to be treated is placed, the atmosphere in the furnace varies, and the atmosphere in the furnace becomes non-uniform.

The present specification discloses a technique capable of suppressing non-uniformity of the furnace atmosphere.

The batch-type heat treatment furnace disclosed in the present specification includes: a furnace body having a top wall and a side wall; a hearth having an upper surface on which an object to be processed is placed; a plurality of heaters disposed in the furnace body, between the side wall and the object to be processed, and disposed along the side wall with a space in a circumferential direction; and a plurality of gas outlets for supplying atmospheric gas into the furnace body. The shape of the furnace formed by the furnace body and the hearth is a cylindrical shape. The plurality of gas outlets are configured to: (1) a heater located between the cylindrical furnace and the object to be processed in the radial direction; (2) circumferentially inside the cylindrical furnace, between circumferentially adjacent heaters. The gas blowing direction in which the gas is blown out from the plurality of gas blowing outlets is the direction of the side wall.

In the batch heat treatment furnace, the plurality of gas outlets are located between the heater and the object to be treated in the radial direction in the furnace, and the atmospheric gas is blown out from the plurality of gas outlets toward the side wall (the inside and outside of the furnace). Therefore, the atmosphere gas blown out from the plurality of gas blowoff ports flows along the side wall after being blown off to the side wall, and the furnace atmosphere is replaced in order from the side wall side toward the center in the furnace. Therefore, the occurrence of variations in the furnace atmosphere at the position where the object to be treated is disposed can be suppressed.

Drawings

FIG. 1 is a cross-sectional view of a batch type heat treatment furnace according to an example.

FIG. 2 is a longitudinal sectional view of a batch type heat treatment furnace according to an example.

Fig. 3 is a diagram for explaining a positional relationship in the circumferential direction between the heater and the gas introduction pipe in the batch-type heat treatment furnace according to the example, and is a diagram obtained by developing a state in which the side wall is viewed from the axis of the heat treatment furnace in the circumferential direction.

Fig. 4 is a view for explaining the direction in which the atmosphere gas is blown out from the gas introduction pipe.

Fig. 5 is an enlarged view of the gas introduction pipe and the gas outlet formed in the gas introduction pipe.

Fig. 6 is a cross-sectional view of a batch-type heat treatment furnace according to a modification.

Fig. 7 is a vertical sectional view of a batch heat treatment furnace according to a modification.

Fig. 8 is a diagram for explaining a positional relationship in the circumferential direction between the heater and the gas introduction pipe in the batch-type heat treatment furnace according to the modification, and is a diagram obtained by developing a state in which the side wall is viewed from the axis of the heat treatment furnace in the circumferential direction.

Fig. 9 is an enlarged view of the side wall and the gas introduction pipe penetrating the side wall.

Description of the symbols

10 … batch heat treatment furnace, 12 … furnace body, 14 … side wall, 15 … inner peripheral surface, 16 … top wall, 20 … hearth, 22 … main hearth, 24 … auxiliary hearth, 26 … fixed bed, 30 … heater, 32 … non-heating part, 34 … heating part, 40 … gas leading-in pipe, S … furnace inner space.

Detailed Description

(feature 1) in the batch-type heat treatment furnace disclosed in the present specification, the gas blowing direction can be adjusted. With such a configuration, the flow of the atmosphere gas in the furnace can be adjusted by adjusting the gas blowing direction.

(feature 2) the batch-type heat treatment furnace disclosed in the present specification may further include: a plurality of gas inlet pipes penetrating the top wall and extending into the furnace body. The gas outlet port may be formed in the gas introduction pipe. The gas introduction pipe may be supported to be rotatable with respect to the ceiling wall, and the gas blowing direction may be adjusted by rotating the gas introduction pipe with respect to the ceiling wall. With such a configuration, the gas blowing direction can be adjusted with a simple configuration.

(feature 3) the batch-type heat treatment furnace disclosed in the present specification may further include: a plurality of gas inlet pipes penetrating the side wall and extending into the furnace body. The gas outlet port may be formed in the gas introduction pipe. With such a configuration, the atmosphere gas can be supplied into the furnace from the side wall side.

(feature 4) in the batch type heat treatment furnace disclosed in the present specification, the plurality of heaters may include: a plurality of upper heaters positioned at an upper portion in the furnace body; a plurality of intermediate section heaters located at an intermediate section in the furnace body; and a plurality of lower heaters positioned at a lower portion in the furnace body. The plurality of gas blowoff ports may include: a plurality of upper gas outlets disposed adjacent to the upper heater; a plurality of intermediate-portion gas outlets disposed adjacent to the intermediate-portion heater; and a plurality of lower gas outlets disposed adjacent to the lower heater. According to such a configuration, since the heater and the gas outlet are provided in the upper portion, the intermediate portion, and the lower portion in the furnace, respectively, the temperature in the furnace and/or the atmosphere in the furnace can be made uniform.

(feature 5) in the batch-type heat treatment furnace disclosed in the present specification, the upper surface of the hearth may be provided with a placement portion for placing the object to be treated. The upper surface may be circular in plan view and may be rotatable about an axis extending in the up-down direction passing through the center thereof. According to such a configuration, the object to be processed revolves, and thus, the entire object to be processed can be uniformly heat-treated.

(feature 6) in the batch-type heat treatment furnace disclosed in the present specification, the upper surface of the hearth may include: a loading part for loading the object to be processed and a non-loading part for not loading the object to be processed. The upper surface may be circular in plan view and may be rotatable about a first axis extending in the up-down direction through the center thereof. The placing section may be circular in plan view and may be rotatable about a second axis passing through the center thereof and extending in the vertical direction. The placing part can revolve by rotating the upper surface around the first axis, and the placing part can rotate by rotating the placing part around the second axis. The revolving direction of the loading unit may be the same direction as or opposite to the rotating direction of the loading unit, and the gas blowing direction may be the same direction as or opposite to the rotating direction of the loading unit. According to such a configuration, the object to be processed is rotated and revolved, and accordingly, the gas blowing direction can be made to coincide with or be opposite to the rotation direction, and the supply form of the atmosphere gas to the furnace can be diversified.

Examples

The batch heat treatment furnace 10 according to the embodiment will be described below. As shown in fig. 1 and 2, the batch heat treatment furnace 10 includes: a hearth 20; a furnace body 12 that covers the top of the hearth 20; and a plurality of heaters 30 and a plurality of gas introduction pipes 40 disposed in a furnace space S formed between the hearth 20 and the furnace body 12.

The hearth 20 is made of refractory material, and includes: a main hearth 22; 4 sub-hearths 24 provided to the main hearth 22; and a fixed bed 26 disposed around the main hearth 22. The main hearth 22 has a disc-like outer shape, and is arranged such that: the central axis (i.e., a line extending in the vertical direction through the center of the main hearth 22) coincides with the axis of the furnace body 12. The main hearth 22 is connected to a drive device (not shown) and is rotatable about its central axis (the axis of the furnace body 12).

The sub-hearth 24 has a disc-like shape and is provided rotatably with respect to the main hearth 22. In the present embodiment, 4 sub-hearths 24 are provided at equal intervals in the circumferential direction (i.e., 4 sub-hearths 24 are provided at 90 ° intervals in the circumferential direction). The 4 sub-hearths 24 are connected to a driving device (not shown) and are rotatable about their axes (i.e., a line extending in the vertical direction through the center of the sub-hearths 24). The axes of the 4 sub-hearths 24 are parallel to the axis of the main hearth 22, and are disposed at equal distances from the axis of the main hearth 22. The upper surface of the main hearth 22 and the upper surface of the sub-hearth 24 are flush with each other, and the object W to be treated can be placed on both the upper surfaces.

The main hearth 22 and the sub-hearth 24 can be stopped from changing the rotation direction and the rotation speed, respectively. The rotation of the primary hearth 22 causes the object W to be processed to perform a so-called revolution, and the rotation of the secondary hearth 24 causes the object W to be processed to perform a so-called rotation. The rotation direction of each of the

hearths

22 and 24 can be set arbitrarily, and the main hearth 22 and the sub-hearth 24 can be rotated clockwise or counterclockwise in fig. 1, or the sub-hearth 24 can be rotated counterclockwise by rotating the main hearth 22 clockwise, or the sub-hearth 24 can be rotated clockwise by rotating the main hearth 22 counterclockwise. By appropriately controlling the rotation speed and rotation direction of the main hearth 22 and the sub-hearth 24, the object W to be treated placed on the main hearth 22 and/or the sub-hearth 24 can be uniformly heated.

The fixed bed 26 is disposed around the primary hearth 22. Specifically, the fixed bed 26 has a ring shape in plan view and is disposed between the main hearth 22 and the side wall 14 of the furnace body 12. The fixed bed 26 is fixed to the casing, and the main hearth 22 and the sub-hearth 24 rotate relative to the fixed bed 26.

The furnace body 12 is made of refractory material, and includes: a cylindrical side wall 14 and a disc-shaped top wall 16. The side wall 14 is constituted: the lower end of which abuts the fixed bed 26 and the upper end of which extends to the top wall 16. The top wall 16 abuts on the upper end of the side wall 14 and closes the opening at the upper end of the side wall 14. In this embodiment, the side wall 14, the ceiling wall 16, and the hearth 20 form a furnace space S in which the object to be processed is processed. Since the hearth 20 and the ceiling wall 16 are formed in a disc shape and the side wall 14 is formed in a cylindrical shape, the furnace space S has a cylindrical shape. From the above description, it can be seen that: the axis of the furnace space S coincides with the axis of the hearth 20. Further, an exhaust port, not shown, is formed in the center of the ceiling wall 16, and gas in the furnace space S can be exhausted to the outside of the furnace through the exhaust port.

The plurality of heaters 30 generate heat by electric power supplied from an external power supply not shown, and control the temperature of the atmosphere in the furnace so as to heat the object W to be processed. As shown in fig. 2 and 3, the plurality of heaters 30 are bent in a U shape, and include: a heat generating portion 34 provided at a portion bent in a U-shape, and 2 non-heat generating portions 32 extending upward from the heat generating portion 34. The heat generating portion 34 is a portion which becomes a high temperature by the energization, and is located in the furnace space S. The non-heating portion 32 is formed of a material having a smaller resistance value than the heating portion 34, penetrates the top wall 16, and has an end located outside the furnace. The heater 30 is constituted by: by adjusting the length of the non-heat generating portion 32, the position of the heat generating portion 34 in the furnace space S (i.e., the position in the vertical direction) can be adjusted. Specifically, the plurality of heaters 30 are classified into:

lower heaters

30a, 30b, 30g, 30h having a heat generating portion 34 located at a lower portion of the furnace space S;

intermediate heaters

30c, 30d, 30i, and 30j, the heat generating parts 34 of which are positioned in the intermediate part of the furnace space S; and

upper heaters

30e, 30f, 30k, and 30l, the heat generating parts 34 of which are located above the furnace space S.

As shown in fig. 1 and 3, the plurality of heaters 30 are positioned radially between the inner circumferential surface 15 of the side wall 14 and the outer circumferential surface of the main hearth 22 (i.e., between the side wall 14 and the object W) with respect to the cylindrical furnace interior space S. The plurality of heaters 30 are disposed in the cylindrical furnace interior space S at intervals along the inner circumferential surface 15 of the side wall 14 in the circumferential direction. Specifically, as shown in fig. 3, 2

lower heaters

30a and 30b are arranged side by side in the circumferential direction, 2

intermediate heaters

30c and 30d are arranged adjacent to the

lower heaters

30a and 30b, and

upper heaters

30e and 30f are arranged adjacent to the

intermediate heaters

30c and 30d, and similarly, the

lower heaters

30g and 30h, the

intermediate heaters

30i and 30j, and the upper heaters 30k and 30l are arranged in this order. Intervals are provided in the circumferential direction between the

lower heaters

30a and 30b, between the

intermediate heaters

30c and 30d, between the

upper heaters

30e and 30f, between the

lower heaters

30g and 30h, between the

intermediate heaters

30i and 30j, and between the upper heaters 30k and 30l, respectively. Intervals are provided in the circumferential direction between the

lower heaters

30a, 30b and the

intermediate heaters

30c, 30d, between the

intermediate heaters

30c, 30d and the

upper heaters

30e, 30f, between the

upper heaters

30e, 30f and the

lower heaters

30g, 30h, between the

lower heaters

30g, 30h and the

intermediate heaters

30i, 30j, and between the

intermediate heaters

30i, 30j and the upper heaters 30k, 30l, respectively.

The plurality of gas introduction pipes 40 are connected to a gas supply source, not shown, and supply the atmosphere gas supplied from the gas supply source toward the furnace space S. As shown in fig. 2 and 3, each of the plurality of gas introduction pipes 40 penetrates the ceiling wall 16 to enter the furnace space S, and its lower end extends to the vicinity of the hearth 20. Since the gas introduction pipe 40 is disposed so as to penetrate the ceiling wall 16, the degree of freedom in designing the disposition position of the gas introduction pipe 40 is improved, and the gas introduction pipe 40 can be disposed at a desired position in the furnace. As shown in fig. 2, the plurality of gas introduction pipes 40a to 40l are disposed radially between the heater 30 and the outer peripheral surface of the main hearth 22 (i.e., between the heater 30 and the object to be treated W) with respect to the furnace space S, and more specifically, at intermediate positions between the heater 30 and the outer peripheral surface of the main hearth 22. The gas introduction pipes 40a to 40l are disposed between the circumferentially adjacent heaters 30a to 30l in the furnace space S in the circumferential direction. Specifically, the heater is disposed between the upper heater 30l and the lower heater 30a, between the lower heater 30a and the lower heater 30b, and between the lower heater 30b and the intermediate heater 30c, and is similarly disposed between all the adjacent heaters 30. Therefore, the plurality of gas introduction pipes 40 can be arranged along the inner circumferential surface 15 of the side wall 14 with a space in the circumferential direction so as not to overlap the heater 30.

As shown in fig. 5, a plurality of gas outlets 42 are formed in the gas introduction pipe 40. The atmosphere gas supplied from the gas supply source to the gas introduction pipe 40 is blown out from the gas blowoff port 42 toward the furnace interior space S. By adjusting the formation position (position in the height direction) of the gas outlet 42 with respect to the gas introduction pipe 40, the position in the height direction at which the atmosphere gas is supplied to the furnace space S can be adjusted. Specifically, as shown in fig. 3, in the gas introduction pipe 40a disposed between the upper heater 30l and the lower heater 30a, gas blowout ports 42 are formed at the same height as the heat generation portions of the upper heater 30l and the lower heater 30a (i.e., at the upper and lower portions of the furnace space S). In the gas introduction pipe 40b disposed between the

lower heaters

30a and 30b, a gas outlet 42 is formed at the same height as the heat generating portions 34 of the

lower heaters

30a and 30b (i.e., at a lower portion of the furnace space S). Hereinafter, similarly, the gas introduction pipes 40c to 40l have gas discharge ports 42 formed at positions corresponding to heat generating portions of the heaters adjacent to the gas introduction pipes. In the present embodiment, although a plurality of gas outlets 42 (fig. 5) are formed in the gas introduction pipe 40, the present invention is not limited to such an example, and for example, a slit-shaped opening extending in the axial direction of the gas introduction pipe 40 may be formed in the gas introduction pipe 40.

Further, as shown in fig. 4, by adjusting the formation position of the gas outlet 42 (the position in the circumferential direction of the gas inlet pipe 40) with respect to the gas inlet pipe 40, the direction in which the atmosphere gas is blown out toward the furnace interior space S can be adjusted. In the present embodiment, as shown in fig. 1 and 4, the direction in which the gas is blown out from the gas outlet 42 is adjusted to a direction toward the inner peripheral surface 15 of the side wall 14 (i.e., a radial direction of the furnace interior space S). As can be seen from fig. 3: the atmospheric gas blown out from the gas outlet 42 of each of the gas introduction pipes 40a to 40l passes through the space between the heaters adjacent to the gas introduction pipes and collides with the inner peripheral surface of the side wall 14.

When the object to be treated W is heat-treated in the batch heat treatment furnace 10, first, the hearth 20 is moved downward with respect to the furnace body 12, and then, the hearth 20 is moved in the horizontal direction, and the object to be treated W is placed on the hearth 20. For example, the object to be treated W is placed on the upper surface of the sub-hearth 24. Next, the hearth 20 is moved in the horizontal direction and disposed directly below the furnace body 12, and then the hearth 20 is moved upward and fitted into the furnace body 12, thereby sealing the furnace space S. After the furnace space S is sealed, the atmosphere gas is supplied from the gas introduction pipe 40 to the furnace space S, and the gas in the furnace space S is discharged from the exhaust port of the ceiling wall 16 to replace the furnace space S with the atmosphere gas. At this time, since the atmosphere gas is blown out from the gas outlet 42 of the gas introduction pipe 40 toward the side wall 14 of the furnace body 12, the furnace space S is gradually replaced with the atmosphere gas from the side wall 14 toward the furnace center. Further, 6 of the gas introduction pipes 40a to 40l blow out the atmosphere gas toward the lower portion in the furnace, 6 of the

gas introduction pipes

40c, 40d, 40e, 40i, 40j, 40k blow out the atmosphere gas toward the middle portion in the furnace, and 6 of the gas introduction pipes 40a to 40l blow out the atmosphere gas toward the upper portion in the furnace, 40a, 40e, 40f, 40g, 40k, 40l blow out the atmosphere gas toward the middle portion in the furnace. Therefore, the atmosphere gas is replaced from the upper portion to the lower portion of the furnace interior space S uniformly in a short time.

After the furnace space S is replaced with the atmosphere gas, power is supplied to the heater 30, and the temperature of the furnace atmosphere is raised to a predetermined temperature while the object W to be processed is heated. At this time, the rotation of the main hearth 22 and the sub-hearth 24 causes the revolution and rotation of the object W, and the entire object W is uniformly heated. The

heaters

30a, 30b, 30g, and 30h heat the lower portion of the object W, the

heaters

30c, 30d, 30i, and 30j heat the middle portion of the object W, and the

heaters

30e, 30f, 30k, and 30l heat the upper portion of the object W. Therefore, the object W can be heated without variation from the upper portion to the lower portion thereof. The output of the heater W is controlled in a predetermined pattern, and the temperature of the object W is changed according to a predetermined temperature profile. Thereby, a desired heat treatment is performed on the object W to be treated. After the heat treatment of the object W is completed, the hearth 20 is moved downward with respect to the furnace body 12, and the object W is taken out from the furnace space S.

Here, when the object W is subjected to the heat treatment, the atmosphere in the furnace space S may be replaced with a new atmosphere from the atmospheric state. In this case, similarly, the atmosphere gas is supplied from the gas introduction pipe 40 to the furnace space S, and the gas in the furnace space S (the atmosphere gas before replacement) is discharged from the exhaust port of the ceiling wall 16, so that the furnace space S is replaced with new atmosphere gas. At this time, power is supplied to the heater 30 to heat the atmosphere gas supplied from the gas introduction pipe 40 to the furnace interior space S. That is, the atmospheric gas from the gas outlet 42 of the gas introduction pipe 40 is blown out toward the side wall 14 of the furnace body 12, collides with the side wall 14, and flows along the inner circumferential surface 15 of the side wall 14. The atmospheric gas is also blown out toward the side wall 14 from the gas outlet 42 of the adjacent gas introduction pipe 40. Accordingly, the atmospheric gas flowing along the side wall 14 next changes the direction of flow toward the center in the furnace. At this time, the heating portion 34 of the heater 30 is present at a position where the atmosphere gas flows. Therefore, the atmospheric gas blown out from the gas outlet 42 of the gas introduction pipe 40 flows toward the center of the furnace space S while being heated by the heat generating portion 34 of the heater 30. Accordingly, the furnace space S is sequentially replaced from the side wall 14 toward the furnace center by the atmospheric gas blown out from the gas blowoff port 42 and heated by the heater 30. Further, since the atmosphere gas is supplied from the plurality of gas introduction pipes 40a to 40l toward the furnace space S, the atmosphere gas is replaced from the upper portion to the lower portion of the furnace space S without variation. Therefore, the ambient temperature is suppressed from becoming uneven in the circumferential direction and the vertical direction around the position where the object to be treated W is placed. This improves the heat treatment quality of the object W.

In the batch-type heat treatment furnace 10, the gas introduction pipe 40 and the heater 30 are arranged at circumferentially displaced positions. Therefore, the heater 30 can be disposed at a position suitable for heating the object to be processed W and controlling the temperature of the atmosphere in the furnace, while the gas introduction pipe 40 can be disposed at a position suitable for controlling the atmosphere in the furnace. Accordingly, the temperature in the furnace and the atmosphere in the furnace can be controlled to a desired state.

In the batch-type heat treatment furnace 10, the atmospheric gas is blown out from the gas outlet 42 of the gas introduction pipe 40 toward the side wall 14 of the furnace space S. Accordingly, the furnace atmosphere is sequentially replaced from the side wall 14 toward the furnace center, and the occurrence of variation in the furnace atmosphere along the circumferential direction at the arrangement position of the object W to be processed can be suppressed.

In the above embodiment, the main hearth 22 and the sub-hearth 24 are configured such that: by changing the drive connection method, the direction in which the atmosphere gas is blown out from the gas outlet 42 can be made the same direction as or opposite to the rotation direction of the main hearth 22 and/or the sub-hearth 24. That is, the main hearth 22 and the sub-hearth 24 may be rotated in the gas blowing direction, or the main hearth 22 and the sub-hearth 24 may be rotated in the direction opposite to the gas blowing direction. Alternatively, one of the main hearth 22 and the sub-hearth 24 may be rotated in the gas blowing direction, and the other of the main hearth 22 and the sub-hearth 24 may be rotated in the direction opposite to the gas blowing direction. In addition, not only the rotation direction but also the rotation speed of the main hearth 22 and the sub-hearth 24 may be changed. By adjusting the rotation direction and/or rotation speed of the main hearth 22 and the sub-hearth 24 independently of the gas blowing direction in this way, the furnace atmosphere and the furnace temperature can be controlled to a desired state.

In the batch-type heat treatment furnace 10 according to the above-described embodiment, the direction in which the atmospheric gas is blown out from the gas outlet 42 is fixed, but the technique disclosed in the present specification is not limited to such an example. For example, the gas introduction pipe 40 may be supported rotatably with respect to the top wall 16, and the direction in which the atmosphere gas is blown out from the gas blow-out port 42 may be changed by rotating the gas introduction pipe 40 about its axis. With this configuration, depending on the operating conditions of the batch heat treatment furnace, the blowing direction of the atmosphere gas may be set to the same direction as or opposite to the rotation direction of the main hearth 22 (the revolving direction of the object W) or the rotation direction of the sub-hearth 24 (the rotating direction of the object W). Accordingly, the ambient temperature and the ambient gas around the object W can be controlled to a desired state. In addition, if this configuration is adopted, the atmosphere gas can be supplied toward the center of the furnace by adjusting the rotation angle of the gas introduction pipe 40 with respect to the ceiling wall 16. In this case, the atmosphere gas supplied from the gas introduction pipe 40 toward the furnace center is rapidly stirred by the object W to be processed which revolves and rotates due to the rotation of the main hearth 22 and the sub-hearth 24, and the atmosphere gas at the furnace center can be replaced in a short time.

In the batch-type heat treatment furnace 10 according to the above-described embodiment, the position of the gas introduction pipe 40 in the furnace radial direction is located between the heater 30 and the outer peripheral surface of the main hearth 22. For example, the gas introduction pipe 40 may be located at the same position as the heater 30 in the furnace radial direction or may be located closer to the inner circumferential surface of the side wall 14.

In the batch-type heat treatment furnace 10 described above, the gas introduction pipe 40 is disposed so as to penetrate the ceiling wall 16, but the technique disclosed in the present specification is not limited to such an example. For example, as shown in fig. 6 and 7, the gas introduction pipe 44 may be disposed so as to penetrate the side wall 14 of the furnace body 12. The gas introduction pipe 44 may be configured to: as shown in fig. 9, includes a horizontal pipe 46 and a vertical pipe 48 connected to a front end of the horizontal pipe 46. In this case, the horizontal tubes 46 penetrate the side wall 14, and the vertical tubes 48 are located in the furnace space S. The vertical pipe 48 is formed with a plurality of

gas outlets

49a, 49b, and the plurality of

gas outlets

49a, 49b are open toward the side wall 14. By disposing the gas introduction pipe 44 as described above, the atmospheric gas can be blown out toward the side wall 14 of the furnace body 12. As shown in fig. 8, the gas introduction pipe 44 is disposed only in: between circumferentially adjacent lower heaters (30a, 30b), (30g, 30h), and between circumferentially adjacent upper heaters (30e, 30f), (30k, 30 l). That is, the gas introduction pipe 44 is not disposed between adjacent heaters 30 having the heat generating portions 34 at different heights, such as between the lower heater 30b and the intermediate heater 30c, and between the intermediate heater 30d and the upper heater 30 e. Accordingly, the length of the vertical pipe 48 can be made to be: the length of the heater is the same as that of the heating part of each heater.

With such a configuration, the same operational effects as those of the above embodiment can be exhibited. In the case where the gas introduction pipe 44 penetrates the side wall 14, similarly, the gas introduction pipe 44 may be supported rotatably about its axis with respect to the side wall 14, and the gas blowing direction may be changed by rotating the gas introduction pipe 44 about its axis.

In the above-described embodiment, the position (position in the height direction) of the gas outlet 42 is set to: a position (position in the height direction) corresponding to the heat generating portion 34 of the heater 30, however, the technique disclosed in the present specification is not limited to such an example. For example, the gas outlet port may be provided at a height corresponding to the position of the non-heat-generating portion, or may be provided over the heat-generating portion and the non-heat-generating portion. Further, the gas outlet provided in the gas introduction pipe adjacent to the upper heater or the intermediate heater may be provided in: the position (height) where the upper heater or the intermediate heater is not provided. For example, the gas introduction pipe adjacent to the upper heater may form a gas outlet at an intermediate height or a lower height of the furnace space S.

Although specific examples of the technology disclosed in the present specification have been described above in detail, these are merely examples and do not limit the claims. The techniques described in the claims include examples in which various modifications and changes are made to the specific examples illustrated above. The technical elements described in the specification and drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing.

Claims

1. A batch-type heat treatment furnace, characterized by comprising:

a furnace body having a top wall and a side wall;

a hearth having an upper surface on which an object to be processed is placed;

a plurality of heaters disposed in the furnace body, between the side wall and the object to be processed, and disposed along the side wall with a space in a circumferential direction; and

a plurality of gas outlets for supplying an atmospheric gas into the furnace body,

the shape of the furnace formed by the furnace body and the hearth is a cylindrical shape,

the plurality of gas blow-out ports are located between the heaters and the object to be processed in a radial direction in the cylindrical furnace, and are located between the heaters adjacent in a circumferential direction in the cylindrical furnace,

the gas blowing direction in which the gas is blown out from the plurality of gas blowing outlets is the direction of the side wall.

2. The batch type heat treatment furnace according to claim 1,

the gas blowing direction can be adjusted.

3. A batch type heat treatment furnace according to claim 2,

the batch-type heat treatment furnace further includes: a plurality of gas introduction pipes extending into the furnace body through the top wall,

the gas outlet is formed in the gas inlet pipe,

the gas introduction pipe is supported to be rotatable with respect to the ceiling wall, and the gas blowing direction can be adjusted by rotating the gas introduction pipe with respect to the ceiling wall.

4. A batch type heat treatment furnace according to claim 2,

the batch-type heat treatment furnace further includes: a plurality of gas introduction pipes extending into the furnace body through the side wall,

the gas outlet is formed in the gas inlet pipe.

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

the plurality of heaters includes:

a plurality of upper heaters positioned at an upper portion in the furnace body;

a plurality of intermediate section heaters located at an intermediate section within the furnace body; and

a plurality of lower heaters positioned at a lower portion in the furnace body,

the plurality of gas outlets include:

a plurality of upper gas outlets disposed adjacent to the upper heater;

a plurality of intermediate-portion gas outlets disposed adjacent to the intermediate-portion heater; and

and a plurality of lower gas outlets disposed adjacent to the lower heater.

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

the upper surface of the hearth is provided with a placing part for placing the object to be treated,

the upper surface is circular in plan view and is rotatable about an axis passing through the center thereof and extending in the vertical direction.

7. A batch type heat treatment furnace according to claim 6,

the upper surface of the hearth is provided with: a loading part for loading the object to be processed, and a non-loading part for not loading the object to be processed,

the upper surface is circular in plan view and is rotatable about a first axis passing through the center thereof and extending in the vertical direction,

the placing section is circular in plan view and is rotatable about a second axis passing through the center thereof and extending in the vertical direction,

the placing part revolves by the rotation of the upper surface around the first axis,

the placing section is rotated about the second axis to rotate,

the revolution direction of the carrying part is the same as or opposite to the rotation direction of the carrying part,

the gas blowing direction is a direction that is the same as or opposite to the rotation direction of the mounting unit.