CN113758236A

CN113758236A - Intermittent heat treatment furnace

Info

Publication number: CN113758236A
Application number: CN202110590475.0A
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: JP2021188893A; JP2021188868A; TW202210775A; JP7077360B2; JP6997350B2

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 shape in the furnace formed by the furnace body and the hearth has a cylindrical shape. The plurality of gas outlets are located between the heaters and the side wall 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 furnace interior direction.

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 heat treatment furnace of patent document 1, since the atmospheric gas is supplied into the furnace while being heated by the heater, the gas outlet port is limited to a position corresponding to the heater. That is, the gas outlet is not provided at a position where the heater is not provided. As a result, the batch heat treatment furnace of patent document 1 has a problem that the furnace atmosphere is likely to become uneven. In particular, in the heat treatment performed in the batch heat treatment furnace, the atmosphere in the furnace may be replaced during the heat treatment. In this case, it is necessary to quickly replace the furnace atmosphere and supply a large amount of atmospheric gas from the gas outlet into the furnace. If the gas outlet is limited to the position of the heater, a large amount of the atmosphere gas is supplied from the limited gas outlet, and therefore the furnace atmosphere is likely to be uneven.

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

The batch heating furnace disclosed in this 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 cylindrical. The plurality of gas outlets are located between the heaters and the side wall 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 furnace interior direction.

In the above-described batch heating furnace, the plurality of gas outlets are located between the heater and the side wall in the radial direction in the cylindrical furnace. Therefore, the atmosphere gas is supplied into the furnace from a position closer to the outer side wall than the heater. The plurality of gas outlets are located between circumferentially adjacent heaters in the circumferential direction in the cylindrical furnace. Therefore, the gas discharge ports can be provided in a desired arrangement between circumferentially adjacent heaters. This can suppress the nonuniformity of the atmosphere in the furnace.

Note that the above-mentioned "between the heater and the side wall" includes: in the same position as the heater, or in the same position as the side wall.

Drawings

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

FIG. 2 is a longitudinal sectional view of a batch type heat treatment furnace according to example 1.

Fig. 3 is a diagram for explaining a positional relationship in the circumferential direction of the heater and the gas introduction pipe, and is a diagram in which the furnace inner wall surface, the heater, and the gas introduction pipe are developed in the circumferential direction as viewed from the center of the furnace.

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

Fig. 5 is a view of the gas introduction pipe as viewed from the side where the gas outlet port is provided.

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

Fig. 7 is a diagram for explaining the structure of a gas introduction pipe according to a modification.

Fig. 8 is a diagram for explaining another structure of the gas introduction pipe according to the modification.

FIG. 9 is a cross-sectional view of a batch type heat treatment furnace according to example 2.

FIG. 10 is a vertical sectional view of a batch type heat treatment furnace according to example 2.

Fig. 11 is a diagram for explaining a positional relationship in the circumferential direction of the heater and the gas introduction pipe, and is a diagram in which the furnace inner wall surface, the heater, and the gas introduction pipe are developed in the circumferential direction as viewed from the center of the furnace.

Fig. 12 is an enlarged view of the gas introduction pipe and the furnace inner wall surface near the position where the gas introduction pipe is disposed.

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, 30a, 30d … lower heater, 30b, 30e … middle heater, 30c, 30f … upper heater, 32 … non-heating part, 34 … heating part, 40 … gas introducing pipe, S … furnace inner space.

Detailed Description

(feature 1) in the batch-type heating furnace disclosed in the present specification, the gas blowing direction may be a direction along the side wall. With such a configuration, the gas supplied from the gas outlet port flows along the side wall. Therefore, the atmosphere in the furnace is sequentially replaced from the side wall toward the center of the furnace. Therefore, the variation in the atmosphere in the furnace in the circumferential direction is suppressed, and the atmosphere in the furnace can be made uniform in the circumferential direction.

(feature 2) in the batch-type heating 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. The gas blowing direction may be the same direction as or opposite to the direction in which the upper surface rotates. According to such a configuration, the object to be processed placed on the upper surface of the placement unit is also rotated in the furnace by rotating the placement unit around the axis. Therefore, the entire object to be treated can be heat-treated. Further, by setting the gas blowing direction to the same direction or the opposite direction with respect to the rotation direction of the mounting portion, the supply mode of the atmosphere gas to the furnace can be changed.

(feature 3) in the batch-type heating 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 passing through the center thereof. The mounting portion 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 unit is capable of revolving around a first axis by the rotation of the upper surface, and capable of rotating around a second axis by the rotation of the placing unit. The revolving direction of the loading unit may be the same direction as or opposite to the rotating direction of the loading unit. The gas blowing direction may be the same as or opposite to the rotation direction of the mounting unit. According to such a configuration, the object to be processed is rotated and revolved, and accordingly, the gas blowing direction can be changed, and the supply form of the atmosphere gas into the furnace can be diversified.

(feature 4) in the batch heating furnace disclosed in the present specification, the plurality of heaters may include: 1 or more upper heaters, the 1 or more upper heaters being located at an upper portion in the furnace body; 1 or more middle section heaters, the 1 or more middle section heaters being located at a middle section in the furnace body; and 1 or more lower heaters, the 1 or more lower heaters being located at a lower portion in the furnace body. The plurality of gas blowoff ports may include: 1 or a plurality of upper gas outlets, the 1 or the plurality of upper gas outlets being disposed at positions adjacent to the upper heater and blowing gas toward the upper heater; 1 or a plurality of intermediate portion gas outlets, the 1 or the plurality of intermediate portion gas outlets being disposed at positions adjacent to the intermediate portion heater and blowing gas toward the intermediate portion heater; and 1 or more lower gas outlets, the 1 or more lower gas outlets being disposed at a position adjacent to the lower heater and blowing gas toward the lower heater. According to such a configuration, the heater and the gas outlet are provided in the upper portion, the intermediate portion, and the lower portion in the furnace, respectively, whereby the temperature in the furnace and/or the atmosphere in the furnace can be made uniform.

(feature 5) the batch-type heating 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. With this configuration, the plurality of gas outlets can be arranged at desired positions in the furnace by the gas introduction pipe penetrating the ceiling wall.

(feature 6) the batch-type heating 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 this configuration, the plurality of gas outlets can be arranged at desired positions in the furnace by the gas introduction pipe penetrating the side wall.

(feature 7) in the batch-type heating furnace disclosed in the present specification, the gas blowing direction may be: the adjustment can be made between a direction orthogonal to the side wall to a direction along the side wall. With such a configuration, the furnace atmosphere can be controlled to a desired state by adjusting the gas blowing direction.

The "direction along the side wall" described above includes not only the direction along the left side wall of the gas outlet but also the direction along the right side wall of the gas outlet when viewed in a cross section passing through the gas outlet and orthogonal to the axis. Therefore, the gas blowing direction can be adjusted within the angular range from the direction along the left side wall to the direction along the right side wall of the gas blowing port.

(feature 8) in the batch-type heating furnace disclosed in the present specification, a plurality of recesses may be formed in the inner wall surface of the side wall so as to be recessed outward in the radial direction. The plurality of recesses may be arranged at intervals in the circumferential direction. The gas outlet port may be located in the recess. According to such a configuration, the furnace internal volume can be reduced as compared with a case where the gas outlet is disposed in the furnace.

(feature 9) the batch-type heating 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 disposed in the recess, the gas introduction pipe being supported to be rotatable with respect to the ceiling wall, and the gas blowing direction being adjustable by the rotation of the gas introduction pipe with respect to the ceiling wall. With such a configuration, the gas blowing direction can be easily adjusted by rotating the gas introduction pipe with respect to the ceiling wall.

(feature 10) in the batch heating furnace disclosed in the present specification, the plurality of heaters may include: 1 or more upper heaters, the 1 or more upper heaters being located at an upper portion in the furnace body; 1 or more middle section heaters, the 1 or more middle section heaters being located at a middle section in the furnace body; and 1 or more lower heaters, the 1 or more lower heaters being located at a lower portion in the furnace body. The plurality of gas blowoff ports may include: 1 or a plurality of upper gas outlets, the 1 or a plurality of upper gas outlets being disposed adjacent to the upper heater; an intermediate gas outlet disposed adjacent to the intermediate heater; and 1 or more lower gas outlets, the 1 or more lower gas outlets being disposed adjacent to the lower heater. According to such a configuration, the heater and the gas outlet are provided in the upper portion, the intermediate portion, and the lower portion in the furnace, respectively, whereby the temperature in the furnace and/or the atmosphere in the furnace can be made uniform.

Examples

Example 1 the batch type heat treatment furnace 10 according to example 1 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 and 30d, the heat generating parts 34 of which are positioned at the lower part of the furnace space S;

intermediate heaters

30b and 30e having heat generating portions 34 located in the intermediate portion of the furnace space S; and

upper heaters

30c and 30f, the heat generating parts 34 of which are positioned 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 30a are arranged side by side in the circumferential direction, 2

intermediate heaters

30b and 30b are arranged adjacent to the

lower heaters

30a and 30a, and

upper heaters

30c and 30c are arranged adjacent to the

intermediate heaters

30b and 30b, and similarly, the

lower heaters

30d and 30d, the

intermediate heaters

30e and 30e, and the

upper heaters

30f and 30f are arranged in this order. Intervals are provided in the circumferential direction between the lower heaters 30a, between the intermediate heaters 30b, between the upper heaters 30c, between the lower heaters 30d, between the intermediate heaters 30e, and between the upper heaters 30f, respectively. Intervals are provided in the circumferential direction between the

lower heaters

30a, 30a and the intermediate heaters 30b, between the

intermediate heaters

30b, 30b and the upper heaters 30c, between the

upper heaters

30c, 30c and the lower heaters 30d, between the

lower heaters

30d, 30d and the intermediate heaters 30e, and between the

intermediate heaters

30e, 30e and the upper heaters 30f, 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 to 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 40f are disposed 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 to be treated W) in the radial direction with respect to the furnace space S, and more specifically, are disposed at substantially the same positions as the heaters 30. The gas introduction pipes 40a to 40f are disposed between the upper heaters 30f and the

lower heaters

30a and 30a, between the lower heaters 30a and the

intermediate heaters

30b and 30b, between the intermediate heaters 30b and the

upper heaters

30c and 30c, between the upper heaters 30c and the

lower heaters

30d and 30d, between the lower heaters 30d and the

intermediate heaters

30e and 30e, and between the intermediate heaters 30e and the

upper heaters

30f and 30f in the circumferential direction with respect to the furnace space S. That is, the plurality of gas introduction pipes 40 are 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 into 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, the gas introduction pipes 40a adjacent to the

lower heaters

30a, 30a have gas outlets 42 formed at the same height as the heat generating portions 34 of the

lower heaters

30a, 30a (i.e., at the lower portion of the furnace space S). In the gas introduction pipe 40b adjacent to the intermediate heaters 30b, a gas blowout port 42 is formed at the same height as the heat generation portion 34 of the

intermediate heaters

30b, 30b (i.e., at the intermediate portion of the furnace space S). The gas introduction pipes 40c adjacent to the

upper heaters

30c, 30c have gas outlets 42 formed at the same height as the heat generating portions 34 of the

upper heaters

30c, 30c (i.e., at the upper portion of the furnace space S). Similarly, the gas inlet pipe 40d has a gas outlet 42 formed in a lower portion of the furnace space S, the gas inlet pipe 40e has a gas outlet 42 formed in an intermediate portion of the furnace space S, and the gas inlet pipe 40f has a gas outlet 42 formed in an upper portion of the furnace space S. 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 be along the inner circumferential surface 15 of the side wall 14 (i.e., the tangential direction of the inner circumferential surface 15). As can be seen from fig. 3: the ambient gas is blown out from the gas outlet 42 of the gas introduction pipe 40a toward the heat generating portions 34 of the lower heaters 30a, from the gas outlet 42 of the gas introduction pipe 40b toward the heat generating portions 34 of the intermediate heaters 30b, and from the gas outlet 42 of the gas introduction pipe 40c toward the heat generating portions 34 of the

upper heaters

30c, 30 c. Similarly, the atmosphere gas is blown out from the gas outlet 42 of the gas introduction pipe 40d toward the heat generating portions 34 of the lower heaters 30d, from the gas outlet 42 of the gas introduction pipe 40e toward the heat generating portions 34 of the intermediate heaters 30e, and from the gas outlet 42 of the gas introduction pipe 40f toward the heat generating portions 34 of the

upper heaters

30f, 30 f.

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 along 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, the atmospheric gas is blown out toward the lower portion in the furnace from the gas outlets 42 of the

gas introduction pipes

40a, 40d, toward the middle portion in the furnace from the gas outlets 42 of the

gas introduction pipes

40b, 40e, and toward the upper portion in the furnace from the gas outlets 42 of the

gas introduction pipes

40c, 40 f. 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 and 30d heat the lower portion of the object W, the

heaters

30b and 30e heat the middle portion of the object W, and the

heaters

30c and 30f 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 space S. That is, the atmosphere gas is blown out from the gas outlet 42 of the gas introduction pipe 40 along the side wall 14 of the furnace body 12, and the heating portion 34 of the heater 30 is present at a position to which the atmosphere gas is blown. Therefore, the atmosphere gas blown out from the gas outlet 42 of the gas introduction pipe 40 flows into 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 40f 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 along the circumferential direction of the furnace internal space. 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 appropriately adjusting the rotation direction and/or the rotation speed of the main hearth 22 and the sub-hearth 24 with respect to the gas blowing direction in this manner, 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 rotation of the main hearth 22 and the sub-hearth 24 (i.e., revolution and rotation of the object W to be processed), 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 the same as the position of the heater 30 in the furnace radial direction, but the technique disclosed in the present specification is not limited to such an example. For example, the gas introduction pipe 40 may be disposed closer to the inner circumferential surface of the side wall 14 than the heater 30.

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. In this case, the gas introducing pipe 44 has a tip positioned in the furnace space S, and forms the gas outlet 42 (see fig. 7) so as to blow the atmosphere gas along the side wall 14. With such a configuration, the same operational effects as those of the batch heat treatment furnace 10 of example 1 can be exhibited. Further, the gas introduction pipe 44 may be short in length as long as the tip end thereof is exposed to the furnace space S. 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.

As shown in fig. 8, the gas introduction pipe 44 penetrating the side wall 14 may be configured to: including a horizontal pipe 46 and a vertical pipe 48 connected to the 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 provided with a plurality of gas outlets 49a to 49c, and the atmosphere gas can be supplied to the furnace space S from the plurality of gas outlets 49a to 49 c.

(example 2) next, a batch type heat treatment furnace 110 according to example 2 will be described. The point of difference between the batch type heat treatment furnace 110 and example 1 is: the gas introduction pipe 140 is embedded in the side wall 114 of the furnace body 112, and has substantially the same configuration as the batch heat treatment furnace 10 of example 1 in other respects. Hereinafter, the difference from embodiment 1 will be mainly described.

As shown in fig. 9 to 11, the batch heat treatment furnace 110 includes, as in example 1: a hearth 120, a furnace body 112, a plurality of heaters 130, and a plurality of gas introduction pipes 140. The hearth 120 has the same configuration as the hearth 20 of example 1, and the heater 130 has the same configuration as the heater 30 of example 1. The batch type heat treatment furnace 110 is different from the furnace body 12 and the gas inlet pipe 40 of example 1 in the furnace body 112 and the gas inlet pipe 140.

The furnace body 112 is made of refractory material and includes a side wall 114 and a ceiling 116. The side wall 114 has substantially the same configuration as the side wall 14 of embodiment 1, but differs therefrom in that: a plurality of recesses 118 are formed in the inner peripheral surface 115 thereof. The plurality of concave portions 118 are arranged at intervals in the circumferential direction, and are provided at the arrangement position of the gas introduction pipe 140. Specifically, the plurality of concave portions 118 are disposed between the adjacent lower heaters 130, between the adjacent middle heaters 130, and between the adjacent

upper heaters

130 and 130, respectively (see fig. 11). Each recess 118 extends from a position of the lower end of the top wall 116 to a position near the hearth 120 in the up-down direction. The opening width in the circumferential direction of each recess 118 is: the center side of the furnace is wide and gradually becomes narrow as it goes away from the center of the furnace (i.e., a shape in which the opening width becomes wider from the outer side of the furnace toward the center (so-called trumpet shape)). The ceiling wall 116 has the same structure as the ceiling wall 16 of embodiment 1.

The plurality of gas introduction pipes 140 have a plurality of gas outlet ports, as in example 1. Each gas introduction pipe 140 penetrates the top wall 116 and is disposed in the recess 118 of the side wall 114. More specifically, the gas introduction pipe 140 is disposed at the bottom (position on the outermost periphery) of the recess 118. Since heater 130 is located inside inner circumferential surface 115 of side wall 114, gas introduction pipe 140 is located outside heater 130. The gas introduction pipe 140 is supported to be rotatable about its axis with respect to the top wall 116. Therefore, as shown in fig. 12, the direction in which the atmosphere gas is blown out from the gas introduction pipe 140 can be adjusted along the circumferential direction within the range of the opening width of the recess 118. That is, the ambient gas from gas introduction pipe 140 can be blown out toward the heat generating portions of heaters 130 arranged on the left and right sides thereof. By blowing the atmosphere gas toward heater 130, a part of the atmosphere gas that collides against the heater flows along inner circumferential surface 115 of side wall 114. As a result, the furnace space S is replaced in order from the outer peripheral side toward the furnace inner side by the atmosphere gas supplied from the gas introduction pipe 140. As a result, the same effects as those of the batch heat treatment furnace 10 of example 1 can be exhibited.

In the batch type heat treatment furnace 110 of example 2, the gas introduction pipe 140 was disposed in the concave portion 118 of the side wall 114. Therefore, the distance between the outer peripheral surface of the main hearth 120 and the inner peripheral surface 115 of the side wall 114 can be shortened, and the volume of the furnace space S can be reduced. As a result, the following can be shortened: the time required for replacing the furnace space S with the atmospheric gas supplied from the gas introduction pipe 140. In addition, the amount of the supplied atmosphere gas can be reduced, and therefore, the heat treatment efficiency can be improved. Further, the heat radiation area of the furnace body 12 can be reduced, and therefore, the capacity of the heater 130 can be reduced.

In the above-described embodiment, the positions (positions in the height direction) of the

gas outlet ports

42 and 142 are provided at positions (positions in the height direction) corresponding to the heat generating portions 34 and 134 of the

heaters

30 and 130, but 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 side wall 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 furnace interior direction.

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

the gas blowout direction is a direction along the side wall.

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

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,

the gas blowing direction is the same direction as or opposite to the direction in which the upper surface rotates.

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

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 the same as or opposite to the rotation direction of the loading unit.

5. The batch heat treatment furnace according to any one of claims 2 to 4,

the plurality of heaters includes:

1 or more upper heaters, the 1 or more upper heaters being located at an upper portion within the furnace body;

1 or more mid-section heaters, the 1 or more mid-section heaters located in a mid-section within the furnace body; and

1 or more lower heaters, the 1 or more lower heaters being located at a lower portion in the furnace body,

the plurality of gas outlets include:

1 or a plurality of upper gas outlets, the 1 or the plurality of upper gas outlets being disposed at positions adjacent to the upper heater and blowing gas toward the upper heater;

1 or a plurality of intermediate portion gas outlets, the 1 or the plurality of intermediate portion gas outlets being disposed at positions adjacent to the intermediate portion heater and blowing gas toward the intermediate portion heater; and

and 1 or more lower gas outlets, the 1 or more lower gas outlets being disposed at a position adjacent to the lower heater and blowing gas toward the lower heater.

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

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.

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

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.

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

the gas blowing direction can be adjusted between a direction orthogonal to the side wall and a direction along the side wall.

9. The batch type heat treatment furnace according to claim 1 or 8,

a plurality of recesses recessed radially outward are formed in an inner wall surface of the side wall,

the plurality of recesses are arranged at intervals in the circumferential direction,

the gas outlet is located in the recess.

10. The batch type heat treatment furnace according to claim 9,

the gas outlet is formed in the gas inlet pipe,

the gas introduction pipe is disposed in the recess,

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.

11. The batch heat treatment furnace according to any one of claims 8 to 10,

the plurality of heaters includes:

the plurality of gas outlets include:

1 or a plurality of upper gas outlets, the 1 or the plurality of upper gas outlets being disposed adjacent to the upper heater;

an intermediate gas outlet disposed adjacent to the intermediate heater; and

and 1 or more lower gas outlets, wherein the 1 or more lower gas outlets are disposed at positions adjacent to the lower heater.

12. 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 gas introduction pipes that supply an atmosphere gas into the furnace body;

a plurality of recesses recessed radially outward are formed in the inner wall surface of the side wall at intervals in the circumferential direction,

the gas introduction pipe is disposed in each of the plurality of concave portions, and includes 1 or a plurality of gas discharge ports,

the gas outlets of the plurality of gas introduction pipes communicate with the furnace interior space, and can blow an atmospheric gas into the furnace interior space.

13. The batch type heat-treating furnace according to claim 12,

the plurality of gas introduction pipes are located radially outside the heaters in the cylindrical furnace, and are located between the heaters adjacent in the circumferential direction in the cylindrical furnace.

14. The batch type heat-treating furnace according to claim 12 or 13,

the plurality of gas introduction pipes extend into the furnace body through the top wall,

the gas introduction pipe is supported to be rotatable with respect to the ceiling wall, and the gas blowing direction can be adjusted within a range of an opening width of the recess by rotating the gas introduction pipe with respect to the ceiling wall.

15. The batch heat treatment furnace according to any one of claims 12 to 14,

the plurality of heaters includes:

the plurality of gas introduction pipes include:

a first gas introduction pipe including 1 or more upper gas discharge ports, the 1 or more upper gas discharge ports being disposed adjacent to the upper heater and discharging gas toward the upper heater;

a second gas introduction pipe that includes 1 or more intermediate portion gas outlets, the 1 or more intermediate portion gas outlets being disposed adjacent to the intermediate portion heater and blowing gas toward the intermediate portion heater; and

and a third gas introduction pipe including 1 or more lower gas discharge ports, the 1 or more lower gas discharge ports being disposed adjacent to the lower heater and discharging gas toward the lower heater.