Heating furnace

Abstract

[Problem] To provide a heating furnace that makes it possible to uniformly cool a heating target. [Solution] A heating furnace 1 comprises: a container 10 having an internal space 11 which is for placing a heating target 2 therein and an inner wall 12 which surrounds the internal space 11; a plurality of gas supply pipes 3a and 3b for supplying a cooling gas to the internal space 11; and a gas discharge pipe for discharging the cooling gas from the internal space 11. The plurality of gas supply pipes 3a and 3b spray the cooling gas into the internal space 11 such that the direction in which the cooling gas is sprayed from the plurality of gas supply pipes 3a and 3b is the same rotation direction.

Description

heating furnace

[0001] The present disclosure relates to a heating furnace for performing heat treatment on a workpiece.

[0002] In a heat treatment process, which is one of the workpiece manufacturing processes, the workpiece, a container in which the workpiece is housed, or a stand on which the workpiece is placed (hereinafter referred to as the "heating object") is housed in a heating furnace, and the workpiece is subjected to heat treatment such as drying, annealing, debinding, and firing. In this disclosure, the term "workpiece" refers to, for example, electronic components such as ceramic capacitors, piezoelectric elements, inductor elements, and semiconductor elements, substrate-like workpieces made of ceramics or semiconductors, and equivalents to electronic components or substrate-like workpieces. Examples of containers for housing workpieces or stands for placing workpieces include saggers, sheaths, and equivalents thereof.

[0003] When the heat treatment of the workpiece is completed, the workpiece is removed from the heating furnace. Then, another workpiece is placed in the heating furnace, and the workpiece is subjected to heat treatment. When the workpiece is removed from the heating furnace, a cooling gas is supplied into the heating furnace to cool the high-temperature workpiece. For example, Patent Documents 1 and 2 disclose techniques in which a cooling gas is sprayed onto the workpiece through multiple cooling nozzles arranged below the workpiece.

[0004] JP 2021-001726 A JP 2022-118690 A

[0005] However, in the technology described in Patent Document 1, the cooling gas is ejected vertically upward from the cooling nozzles and sprayed onto the underside of the object to be heated. Therefore, depending on the number of cooling nozzles, the object to be heated may not be cooled uniformly, and there is a risk of the object being damaged.

[0006] In addition, in the technology described in Patent Document 2, the cooling gas is ejected from the cooling nozzle obliquely upward relative to the vertical direction and flows along the underside of the object to be heated. Therefore, depending on the area of ​​the underside of the object to be heated, the object to be heated may not be cooled uniformly, and there is a risk of the object being damaged.

[0007] The present disclosure provides a heating furnace capable of uniformly cooling an object to be heated.

[0008] The heating furnace of the present disclosure comprises a container having an internal space for placing an object to be heated and an inner wall surrounding the internal space, a plurality of gas supply pipes for supplying cooling gas to the internal space, and a gas discharge pipe for discharging the cooling gas from the internal space, wherein the plurality of gas supply pipes spray the cooling gas into the internal space so that the spray directions of the cooling gas sprayed from the plurality of gas supply pipes are in the same rotational direction.

[0009] In the heating furnace of the present disclosure, multiple gas supply pipes eject cooling gas into the interior space so that the ejection directions of the cooling gas from the multiple gas supply pipes are in the same rotational direction. Therefore, the cooling gas supplied from the multiple gas supply pipes cooperates to form a swirling airflow that swirls in the interior space. As a result, the cooling gas is blown onto the object to be heated along the swirling direction of the swirling airflow, allowing the object to be cooled uniformly along the swirling direction of the swirling airflow.

[0010] FIG. 1 is a cross-sectional view of a heating furnace according to a first embodiment. FIG. 2 is a perspective view showing the internal configuration of the heating furnace shown in FIG. 1. FIG. 3 is a cross-sectional plan view of the heating furnace shown in FIG. 2. FIG. 4 is a cross-sectional plan view of a modified example of the heating furnace shown in FIG. 3. FIG. 5 is a cross-sectional plan view of a heating furnace according to a second embodiment. FIG. 6 is a cross-sectional plan view of a modified example of the heating furnace shown in FIG. 5. FIG. 7 is a cross-sectional plan view of a heating furnace according to a third embodiment. FIG. 8 is a cross-sectional plan view of a modified example of the heating furnace shown in FIG. 7. FIG. 9 is a cross-sectional plan view of a modified example of the heating furnace shown in FIG. 7. FIG. 10 is a cross-sectional plan view of a heating furnace according to a fourth embodiment. FIG. 11 is a cross-sectional plan view of a modified example of the heating furnace shown in FIG. 10. FIG. 12 is a cross-sectional plan view of a heating furnace according to a fifth embodiment. FIG. 13 is a cross-sectional plan view of a heating furnace according to a sixth embodiment. FIG. 14 is a cross-sectional plan view of a heating furnace according to a seventh embodiment. FIG. 15 is a cross-sectional plan view of a modified example of the heating furnace shown in FIG. 1.

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the contents shown in the drawings are merely schematic and illustrative for understanding the present disclosure, and the appearance and dimensional ratios may differ from the actual product. Furthermore, the present disclosure is not limited to the following embodiments.

[0012] (First Embodiment) The heating furnace 1 shown in FIG. 1 is a heating furnace for performing heat treatments such as drying, annealing, debinding, and firing on workpieces in a heat treatment process, which is one of the workpiece manufacturing processes. In the heat treatment process, the workpieces, a container containing the workpieces, or a table on which the workpieces are placed (hereinafter, these will be referred to as "heating objects") are placed in the heating furnace 1. In the present disclosure, the term "workpiece" refers to, for example, electronic components such as ceramic capacitors, piezoelectric elements, inductor elements, and semiconductor elements, substrate-like workpieces made of ceramics or semiconductors, or equivalents to electronic components or substrate-like workpieces. Examples of containers for containing workpieces or tables for placing workpieces include saggers, sheaths, and equivalents thereof. The heating furnace 1 is, for example, a batch-type heating furnace.

[0013] The container for accommodating the workpieces or the table on which the workpieces are placed is made of a heat-resistant material. The material for composing the container for accommodating the workpieces or the table on which the workpieces are placed is not particularly limited, but may be, for example, ceramics such as alumina, magnesia, zirconia, or silicon carbide, metals such as stainless steel, or carbon. The container for accommodating the workpieces may be provided with intake and exhaust pipes for adjusting the atmosphere or temperature inside the container depending on the purpose of the heat treatment.

[0014] The heating furnace 1 has at least a container 10, gas supply pipes 3a and 3b, and a gas exhaust pipe 4. The heating furnace 1 further has a heat source 5 and a support 6 (FIG. 2), but these components are not essential. In the heat treatment process, the container 10 is placed in a heating space with the heating object 2 accommodated therein, and is heated by the heat source 5. The diameter of the container 10 is not particularly limited, but is 100 mm to 300 mm. The height of the container 10 is not particularly limited, but is 6 mm to 30 mm.

[0015] The container 10 is made of a heat-resistant material. The material for the container 10 is not particularly limited, but may be, for example, ceramics such as alumina, magnesia, zirconia, or silicon carbide, metals such as stainless steel, or carbon. The container 10 has an internal space 11, an inner wall 12, a bottom 13, and a top 14.

[0016] Hereinafter, the direction from the bottom 13 to the top 14 along the axial direction of the container 10 (the extension direction of the central axis D of the container 10) will be referred to as "upward." Furthermore, the direction from the top 14 to the bottom 13 along the axial direction of the container 10 will be referred to as "downward." However, "upward" in this disclosure does not necessarily coincide with upward in the vertical direction. Furthermore, "downward" in this disclosure does not necessarily coincide with downward in the vertical direction.

[0017] The internal space 11 is a space for placing the object to be heated 2, and is surrounded by an inner wall 12, a bottom 13, and a top 14. The shapes of the bottom 13 and the top 14 are circular in a plan view, but may be elliptical, rectangular, other polygonal, or other shapes. The bottom 13 faces the top 14 along the axial direction of the container 10.

[0018] The inner wall 12 extends along the circumferential direction of the container 10 and surrounds the internal space 11. The shape of the inner wall 12 is circular in a plan view, but may be elliptical, rectangular, other polygonal, or other shapes.

[0019] As shown in Fig. 2, the support 6 is made up of a rod-shaped member and supports the object to be heated 2. The support 6 is provided on the bottom 13 and extends along the axial direction of the container 10. In the example shown in Fig. 2, a plurality of supports 6 are provided on the bottom 13, but the number of supports 6 is not particularly limited. The object to be heated 2 is placed at the tips of the plurality of supports 6.

[0020] The gas supply pipes 3a and 3b are connected to the inner wall 12 and supply cooling gas to the internal space 11. In this embodiment, there are two gas supply pipes, but as described below, there may be three or more. The outer and inner cross-sectional shapes of the gas supply pipes 3a and 3b are circular, but may also be elliptical, rectangular, other polygonal, or other shapes. The cooling gas is not particularly limited, but may be, for example, an inert gas such as nitrogen, helium, or argon, a reducing gas including hydrogen, or an oxidizing gas including oxygen and water vapor. The gas supply pipes 3a and 3b have a cylindrical shape and extend linearly. However, the gas supply pipes 3a and 3b may be bent or curved.

[0021] 1 , gas supply pipe 3a is inserted into gas supply hole 15a formed in inner wall 12. Gas supply pipe 3b is inserted into gas supply hole 15b formed in inner wall 12. Gas supply holes 15a and 15b are through-holes that penetrate inner wall 12. Gas supply pipes 3a and 3b protrude from inner wall 12 toward the inside of container 10. However, the tip surfaces of gas supply pipes 3a and 3b may be flush with the inner circumferential surface of inner wall 12.

[0022] The height position of gas supply pipe 3a is equal to the height position of gas supply pipe 3b. In the present disclosure, the height direction corresponds to the axial direction of container 10. Furthermore, the term "equal" does not only refer to a state in which the physical quantities of the multiple objects being compared are strictly equal, but also includes a state in which there is an error of ±Δ% or less (for example, Δ=7, 5, or 3, but this is not limited thereto).

[0023] The height position of the gas supply pipe 3a may be higher or lower than the height position of the gas supply pipe 3b. The height position of the gas supply pipe 3a is equal to the height position of the object to be heated 2, but may be higher or lower than this. The gas supply pipes 3a and 3b are provided at the center of the inner wall 12 in the height direction, but may be provided above or below the center of the inner wall 12 in the height direction.

[0024] As shown in Figure 3, in a plan view, the internal space 11 is divided into four quadrants by an arbitrary first axis L1 passing through the center (center of gravity) C of the internal space 11 or the container 10, and a second axis L2 perpendicular to the first axis L1. The gas supply pipe 3a ejects cooling gas into the internal space 11 in the first quadrant Q1. The gas supply pipe 3b ejects cooling gas into the internal space 11 in the third quadrant Q3. That is, the gas supply pipes 3a and 3b eject cooling gas into the internal space 11 in different quadrants. The gas supply pipes 3a and 3b eject cooling gas into the internal space 11 in quadrants that face each other across the center C of the internal space 11.

[0025] The gas supply pipe 3a ejects the cooling gas along the second axis L2 from the first quadrant Q1 to the second quadrant Q2, and the gas supply pipe 3b ejects the cooling gas along the second axis L2 from the third quadrant Q3 to the fourth quadrant Q4.

[0026] In this embodiment, the ejection direction A1 of the cooling gas ejected from the gas supply pipe 3a and the ejection direction A2 of the cooling gas ejected from the gas supply pipe 3b are parallel. Furthermore, the ejection directions A1 and A2 are parallel to the second axis L2. That is, the gas supply pipes 3a and 3b eject the cooling gas along the second axis L2. In this disclosure, "parallel" does not only refer to strict parallelism, but also includes a state in which there is an error of ±Δθ° (for example, Δθ = 3) or less from strict parallelism. Furthermore, "perpendicular" or "orthogonal" does not only refer to strict perpendicular or perpendicular, but also includes a state in which there is an error of ±Δθ° (for example, Δθ = 3) or less from strict perpendicular or perpendicular.

[0027] A line extending along the ejection direction A1 of the cooling gas ejected from the gas supply pipe 3a is defined as a first imaginary line I1, and a line extending along the ejection direction A2 of the cooling gas ejected from the gas supply pipe 3b is defined as a second imaginary line I2. The first imaginary line I1 is a line that is an imaginary extension of the axis of the gas supply pipe 3a, and the second imaginary line I2 is a line that is an imaginary extension of the axis of the gas supply pipe 3b. The gas supply pipe 3a ejects the cooling gas so that the first imaginary line I1 intersects with the heating object 2 (excluding the outer periphery of the heating object 2). The gas supply pipe 3b ejects the cooling gas so that the second imaginary line I2 intersects with the heating object 2 (excluding the outer periphery of the heating object 2). The first imaginary line I1 and the second imaginary line I2 are perpendicular to the first axis L1.

[0028] 4 , the gas supply pipe 3a may eject the cooling gas so that the first virtual line I1 does not intersect with the object to be heated 2. Furthermore, the gas supply pipe 3b may eject the cooling gas so that the second virtual line I2 does not intersect with the object to be heated 2. The first virtual line I1 passes between the outer periphery and the inner wall 12 of the object to be heated 2 so as to be perpendicular to the first axis L1. Furthermore, the second virtual line I2 passes between the outer periphery and the inner wall 12 of the object to be heated 2 so as to be perpendicular to the first axis L1.

[0029] As shown in FIG. 3 , positions on the outer periphery of the object to be heated 2 that are located on opposite sides of each other along a first axis L1 are designated as a first position P1 and a second position P2. The first position P1 is one of the intersections of the first axis L1 and the outer periphery of the object to be heated 2. The second position P2 is the other of the intersections of the first axis L1 and the outer periphery of the object to be heated 2. In this embodiment, the distance along the first axis L1 between the first virtual line I1 and the second virtual line I2 is smaller than the distance along the first axis L1 between the first position P1 and the second position P2 (i.e., the diameter of the object to be heated 2). On the other hand, in the example shown in FIG. 4 , the distance along the first axis L1 between the first virtual line I1 and the second virtual line I2 is larger than the distance along the first axis L1 between the first position P1 and the second position P2 (i.e., the diameter of the object to be heated 2).

[0030] When viewed in a direction parallel to the second axis L2, the gas supply pipe 3a is, although not limited to, closer to the first position P1 than to the center C of the container 10. When viewed in a direction parallel to the second axis L2, the gas supply pipe 3b is, although not limited to, closer to the second position P2 than to the center C of the container 10.

[0031] When viewed from the direction along the second axis L2, the gas supply pipe 3a is positioned so as to overlap the object to be heated 2 as a whole. When viewed from the direction along the second axis L2, the gas supply pipe 3b is positioned so as to overlap the object to be heated 2 as a whole. On the other hand, in the example shown in Fig. 4, when viewed from the direction along the second axis L2, the gas supply pipe 3a is positioned so as to overlap the object to be heated 2 as a whole and the inner wall 12 (particularly, the intersection with the first axis L1). When viewed from the direction along the second axis L2, the gas supply pipe 3b is positioned so as to overlap the object to be heated 2 as a whole and the inner wall 12 (particularly, the intersection with the first axis L1).

[0032] 3 , the cooling gas ejected from the gas supply pipe 3a has a direction A1 that is different from (opposite to) the direction A2 of the cooling gas ejected from the gas supply pipe 3b. That is, the gas supply pipes 3a and 3b eject the cooling gas into the internal space 11 so that the ejection directions A1 and A2 of the cooling gas ejected from the gas supply pipes 3a and 3b are in the same rotational direction (counterclockwise). At least a portion of the cooling gas ejected from the gas supply pipe 3a flows along the first imaginary line I1, is blown against the inner wall 12, and flows counterclockwise along the inner wall 12. At least a portion of the cooling gas ejected from the gas supply pipe 3b flows along the second imaginary line I2, is blown against the inner wall 12, and flows counterclockwise along the inner wall 12.

[0033] The cooling gas ejected from gas supply pipe 3a and flowing counterclockwise along inner wall 12 joins with the cooling gas ejected from gas supply pipe 3b and flowing counterclockwise along inner wall 12 to form a swirling airflow swirling in internal space 11. In this manner, in this embodiment, the cooling gases supplied to internal space 11 from gas supply pipes 3a and 3b cooperate to form a swirling airflow swirling in internal space 11.

[0034] For ease of understanding, the approximate swirling direction of the swirling airflow is indicated by arrow B in FIG. 3 . In this embodiment, as indicated by arrow B, a counterclockwise swirling airflow is formed in the internal space 11. The gas supply pipes 3a and 3b eject cooling gas in opposite directions (toward each other) so that a counterclockwise swirling airflow is formed in the internal space 11. The gas supply pipes 3a and 3b also eject cooling gas along the swirling direction of the swirling airflow so that at least a portion of the cooling gas ejected from the gas supply pipes 3a and 3b flows along the swirling airflow (constitutes at least a portion of the swirling airflow). For example, the gas supply pipe 3a ejects cooling gas along the swirling direction of the swirling airflow at and around the first position P1. The gas supply pipe 3b ejects cooling gas along the swirling direction of the swirling airflow at and around the second position P2. However, the periphery of the first position P1 includes a position between the first position P1 and a position that is a distance Δ away from the first position P1. Furthermore, the periphery of the second position P2 includes a position between the second position P2 and a position that is a distance Δ away from the second position P2. The distance Δ is not particularly limited, but may be, for example, 1 / 10 or 1 / 15 of the diameter of the container 10. The angle of the first virtual line I1 with respect to the first axis L1 or the second axis L2 and the angle of the second virtual line I2 with respect to the first axis L1 or the second axis L2 are not limited to the angles shown in FIG. 3 as long as they are angles that can form a swirling airflow in the internal space 11.

[0035] As shown in Fig. 2, the gas exhaust pipe 4 is provided in the bottom 13 and exhausts the cooling gas from the internal space 11. The gas exhaust pipe 4 is located in the center of the container 10 in a plan view. The center of the container 10 includes not only the center C of the container 10 but also a position between the center C and a position that is a distance Δ away from the center C along the radial direction of the container 10. The distance Δ is not particularly limited, and may be, for example, 1 / 10 or 1 / 15 of the diameter of the container 10. However, the gas exhaust pipe 4 may be located at a position other than the center of the container 10.

[0036] As shown in FIG. 1 , the gas exhaust pipe 4 has a cylindrical shape and extends linearly. However, the gas exhaust pipe 4 may be bent or curved. The cross-sectional shapes of the outer and inner circumferences of the gas exhaust pipe 4 are circular, but may also be elliptical, rectangular, other polygonal, or other shapes. In this embodiment, there is one gas exhaust pipe 4, but as described below, there may be two or more gas exhaust pipes. In the example shown in FIG. 1 , the gas exhaust pipe 4 is integrally formed with the bottom 13, but it may also be configured separately from the container 10. For example, the cylindrical gas exhaust pipe 4 configured separately from the container 10 may be inserted into a gas exhaust hole 16 formed in the bottom 13. In this case, the gas exhaust pipe 4 may protrude upward from the bottom 13 toward the inside of the container 10.

[0037] 3, in the heating furnace 1 of this embodiment, the gas supply pipes 3a and 3b eject the cooling gas into the internal space 11 so that the ejection directions A1 and A2 of the cooling gas ejected from the gas supply pipes 3a and 3b are the same rotational direction (counterclockwise). Therefore, the cooling gases supplied from the gas supply pipes 3a and 3b cooperate to form a swirling airflow that swirls in the internal space 11. As a result, the cooling gas is blown toward the object to be heated 2 along the swirling direction of the swirling airflow, and the object to be heated 2 can be uniformly cooled along the swirling direction of the swirling airflow.

[0038] Furthermore, when the internal space 11 is divided into four quadrants Q1 to Q4 in a plan view by an arbitrary first axis L1 passing through the center C of the internal space 11 and a second axis L2 perpendicular to the first axis L1, the gas supply pipes 3a and 3b eject cooling gas into the internal space 11 in different quadrants (the first quadrant Q1 and the third quadrant Q3). Therefore, the cooling gases ejected in the different quadrants join together in the internal space 11, and the joined cooling gases can form a swirling air current in the internal space 11.

[0039] Furthermore, the gas supply pipes 3a and 3b eject the cooling gas into the internal space 11 in quadrants (first quadrant Q1 and third quadrant Q3) that face each other across the center C. This makes it easier to form a swirling airflow that is symmetrical with respect to the first axis L1 or the second axis L2, and the object 2 to be heated can be uniformly cooled along the swirling direction of the swirling airflow.

[0040] The direction of the cooling gas ejected from the gas supply pipe 3 a is parallel to the direction of the cooling gas ejected from the gas supply pipe 3 b, which makes it easier to form a swirling airflow that circulates (one full revolution) around the internal space 11, thereby enabling the object 2 to be uniformly cooled.

[0041] 2, the gas exhaust pipe 4 is located in the center of the container 10 in a plan view. Therefore, a swirling airflow with the center of the container 10 as the swirl center (swirl axis) is easily formed in the internal space 11, and the object 2 to be heated can be uniformly cooled.

[0042] Furthermore, the gas exhaust pipe 4 is provided at the bottom 13 of the container 10. Therefore, the cooling gas is exhausted from the bottom 13 of the container 10. This makes it easier to form a three-dimensional swirling airflow in the internal space 11, thereby enabling uniform cooling of the entire object to be heated 2. Furthermore, the cooling gas is not exhausted from the inner wall 12 of the container 10, making it easier to form a swirling airflow in the internal space 11.

[0043] Second Embodiment A heating furnace 1A of a second embodiment shown in Fig. 5 has the same configuration as the heating furnace 1 of the first embodiment, except for the following points: Parts that overlap with those of the heating furnace 1 of the first embodiment are given the same reference numerals, and detailed descriptions thereof will be omitted.

[0044] In this embodiment, the gas supply pipe 3a ejects the cooling gas so that the first virtual line I1 contacts a first position P1 on the outer periphery of the heating object 2. The gas supply pipe 3b ejects the cooling gas so that the second virtual line I2 contacts a second position P2 on the outer periphery of the heating object 2. The first virtual line I1 and the second virtual line I2 are perpendicular to the first axis L1 and parallel to the second axis L2. The first virtual line I1 and the second virtual line I2 correspond to tangents to the heating object 2.

[0045] 6 , the gas supply pipe 3a may eject the cooling gas into the internal space 11 in the fourth quadrant Q4. Alternatively, the gas supply pipe 3b may eject the cooling gas into the internal space 11 in the second quadrant Q2. In this case, as shown by arrow B, a clockwise swirling airflow can be formed in the internal space 11.

[0046] In this embodiment, the same effects as in the first embodiment can be obtained. Additionally, in this embodiment, the ejection direction A1 of the cooling gas ejected from the gas supply pipe 3a is directed toward the first position P1. Furthermore, the ejection direction A2 of the cooling gas ejected from the gas supply pipe 3b is directed toward the second position P2. Therefore, the cooling gas ejected from the gas supply pipe 3a and the cooling gas ejected from the gas supply pipe 3b do not collide head-on with each other. This makes it easier to form a swirling airflow in the internal space 11.

[0047] In some embodiments, the ejection direction A1 of the cooling gas ejected from the gas supply pipe 3a may be directed toward the first position P1 so that the first virtual line I1 does not contact the first position P1 of the heating object 2. Furthermore, the ejection direction A2 of the cooling gas ejected from the gas supply pipe 3b may be directed toward the second position P2 so that the second virtual line I2 does not contact the second position P2 of the heating object 2.

[0048] Furthermore, the distance along the first axis L1 between the first virtual line I1 and the second virtual line I2 is equal to the distance along the first axis L1 between the first position P1 and the second position P2 (i.e., the diameter of the object to be heated 2). Therefore, the swirling airflow flows near the object to be heated 2, making it easier to cool the object to be heated 2. Furthermore, the ejection direction A1 of the cooling gas ejected from the gas supply pipe 3a and the ejection direction A2 of the cooling gas ejected from the gas supply pipe 3b are parallel to each other, making it easier to form a swirling airflow in the internal space 11.

[0049] 7 has the same configuration as the heating furnace 1A of the second embodiment, except for the following points: The same reference numerals are used to designate parts that overlap with the heating furnace 1A of the second embodiment, and detailed descriptions thereof will be omitted.

[0050] 7 , the gas supply pipe 3a ejects the cooling gas into the internal space 11 in the second quadrant Q2. The gas supply pipe 3b ejects the cooling gas into the internal space 11 in the third quadrant Q3. That is, the gas supply pipes 3a and 3b eject the cooling gas into the internal space 11 in different quadrants. The gas supply pipes 3a and 3b eject the cooling gas into the internal space 11 in quadrants that face each other across the second axis L2.

[0051] The gas supply pipe 3a ejects cooling gas along the first axis L1 in a direction from the second quadrant Q2 to the third quadrant Q3. The gas supply pipe 3b ejects cooling gas along the second axis L2 in a direction from the third quadrant Q3 to the fourth quadrant Q4. The ejection direction A1 of the cooling gas ejected from the gas supply pipe 3a and the ejection direction A2 of the cooling gas ejected from the gas supply pipe 3b are non-parallel (perpendicular).

[0052] In this embodiment as well, the cooling gas ejected from gas supply pipe 3a and the cooling gas ejected from gas supply pipe 3b join together to form a swirling airflow that swirls counterclockwise in internal space 11. That is, gas supply pipes 3a and 3b eject the cooling gas into internal space 11 so that the ejection directions of the cooling gases ejected from gas supply pipes 3a and 3b are the same rotational direction (counterclockwise).

[0053] The first imaginary line I1 is tangent to the outer periphery of the object to be heated 2 and is parallel to the first axis L1. That is, the gas supply pipe 3a ejects the cooling gas so that the first imaginary line I1 is tangent to the outer periphery of the object to be heated 2. The second imaginary line I2 is tangent to the outer periphery of the object to be heated 2 and is parallel to the second axis L2. That is, the gas supply pipe 3b ejects the cooling gas so that the second imaginary line I2 is tangent to the outer periphery of the object to be heated 2.

[0054] The gas supply pipe 3a may eject the cooling gas in a quadrant different from the second quadrant Q2. For example, the gas supply pipe 3a may eject the cooling gas in the first quadrant Q1 so that the first virtual line I1 and the second virtual line I2 are perpendicular to each other. In addition, although the swirling airflow swirls counterclockwise in this embodiment, the gas supply pipes 3a and 3b may eject the cooling gas so that the swirling airflow swirls clockwise.

[0055] As shown in Fig. 8, the ejection direction A2 (second imaginary line I2) of the cooling gas ejected from the gas supply pipe 3b may be inclined with respect to the first axis L1 and the second axis L2. Furthermore, as shown in Fig. 9, in addition to the ejection direction A2 (second imaginary line I2) of the cooling gas ejected from the gas supply pipe 3b, the ejection direction A1 (first imaginary line I1) of the cooling gas ejected from the gas supply pipe 3a may also be inclined with respect to the first axis L1 and the second axis L2. In this case as well, the cooling gas ejected from the gas supply pipe 3a and the cooling gas ejected from the gas supply pipe 3b join together to form a swirling airflow swirling in the internal space 11.

[0056] In this embodiment, the same effects as in the second embodiment can be obtained. In addition, in this embodiment, the ejection direction A1 of the cooling gas ejected from the gas supply pipe 3a and the ejection direction A2 of the cooling gas ejected from the gas supply pipe 3b are non-parallel. For example, by making the ejection directions of the cooling gas ejected from the gas supply pipe 3a and the gas supply pipe 3b non-parallel depending on the shape of the object to be heated 2, the cooling efficiency of the object to be heated 2 can be improved.

[0057] 10 has the same configuration as the heating furnace 1 of the first embodiment, except for the following points: The same reference numerals are used to designate parts that overlap with the heating furnace 1 of the first embodiment, and detailed descriptions thereof will be omitted.

[0058] 10 , at least a portion of the gas supply pipe 3a is provided along the inner wall 12 (particularly, the inner circumferential surface of the inner wall 12). At least a portion of the gas supply pipe 3b is provided along the inner wall 12 (particularly, the inner circumferential surface of the inner wall 12). The ejection direction A1 (first imaginary line I1) of the cooling gas ejected from the gas supply pipe 3a and the ejection direction A2 (second imaginary line I2) of the cooling gas ejected from the gas supply pipe 3b are inclined with respect to the first axis L1 and the second axis L2.

[0059] Here, a tangent line L3 is a straight line tangent to the outer periphery of the inner wall 12 at the intersection of the first virtual line I1 and the outer periphery of the inner wall 12. A tangent line L4 is a straight line tangent to the outer periphery of the inner wall 12 at the intersection of the second virtual line I2 and the outer periphery of the inner wall 12. The angle θ1 between the tangent line L3 and the first virtual line I1 is not particularly limited, but may be 5°≦θ1≦60°, 10°≦θ1≦45°, or 20°≦θ1≦40°. The angle θ2 between the tangent line L4 and the second virtual line I2 is equal to the angle θ1 between the tangent line L3 and the first virtual line I1, but may be different.

[0060] The gas supply pipe 3a and the gas supply pipe 3b eject the cooling gas into the internal space 11 in quadrants that face each other across the second axis L2. As shown in Fig. 11 , the gas supply pipe 3a and the gas supply pipe 3b may eject the cooling gas into the internal space 11 in quadrants that face each other across the center C of the internal space 11.

[0061] The same effects as those of the first embodiment can be obtained in this embodiment. In addition, in this embodiment, the gas supply pipes 3 a and 3 b are provided along the inner wall 12. Therefore, a swirling airflow is easily formed along the inner wall 12, and the object to be heated 2 can be uniformly cooled along the swirling direction of the swirling airflow.

[0062] Fifth Embodiment A heating furnace 1D of a fifth embodiment shown in Fig. 12 has the same configuration as the heating furnace 1A of the second embodiment, except for the following points: Parts that overlap with those of the heating furnace 1A of the second embodiment are given the same reference numerals, and detailed descriptions thereof will be omitted.

[0063] The heating furnace 1D further includes gas supply pipes 3c and 3d in addition to the gas supply pipes 3a and 3b. The gas supply pipe 3c is located on the second axis L2 and extends along the second axis L2. The gas supply pipe 3c ejects cooling gas into the internal space 11 along the second axis L2. The gas supply pipe 3d is located on the second axis L2 and extends along the second axis L2. The gas supply pipe 3d ejects cooling gas into the internal space 11 along the second axis L2. The ejection direction A3 of the cooling gas ejected from the gas supply pipe 3c is opposite (approaching each other) to the ejection direction A4 of the cooling gas ejected from the gas supply pipe 3d. The gas supply pipes 3c and 3d eject cooling gas toward the center C of the container 10.

[0064] 12, each of the gas supply pipes 3c and 3d may be located in, for example, any of the first quadrant Q1 to the fourth quadrant Q4. Furthermore, the orientation of the gas supply pipes 3c and 3d is not limited to the orientation shown in FIG. 12, and at least one of the gas supply pipes 3c and 3d may be inclined with respect to, for example, the first axis L1 and the second axis L2.

[0065] In this embodiment, the same effects as those in the second embodiment can be obtained. In addition, in this embodiment, the heating furnace 1D has gas supply pipes 3c and 3d in addition to the gas supply pipes 3a and 3b. Therefore, the cooling efficiency of the heating object 2 can be improved.

[0066] 13 has the same configuration as the heating furnace 1A of the second embodiment, except for the following points: The same reference numerals are used to designate parts that overlap with the heating furnace 1A of the second embodiment, and detailed descriptions thereof will be omitted.

[0067] The heating furnace 1E has a gas supply pipe 3c in addition to the gas supply pipes 3a and 3b. A line along the ejection direction A3 of the cooling gas ejected from the gas supply pipe 3c is defined as a third imaginary line I3. The third imaginary line I3 is a line that is an imaginary extension of the axis of the gas supply pipe 3c.

[0068] The first imaginary line I1 and the third imaginary line I3 are parallel to the first axis L1 and perpendicular to the second axis L2. The second imaginary line I2 is parallel to the second axis L2 and perpendicular to the first axis L1. The first imaginary line I1, the second imaginary line I2, and the third imaginary line I3 correspond to tangents to the object 2 to be heated.

[0069] 13 , the first position P1 and the second position P2 are located on opposite sides of the outer periphery of the object to be heated 2 along the second axis L2. The first position P1 is one of the intersections of the second axis L2 and the outer periphery of the object to be heated 2. The second position P2 is the other of the intersections of the second axis L2 and the outer periphery of the object to be heated 2. The third position P3 is the intersection of the first axis L1 and the outer periphery of the object to be heated 2.

[0070] In this embodiment, the gas supply pipe 3a ejects the cooling gas so that the first virtual line I1 contacts a first position P1 on the outer periphery of the heating object 2. The gas supply pipe 3b ejects the cooling gas so that the second virtual line I2 contacts a third position P3 on the outer periphery of the heating object 2. The gas supply pipe 3c ejects the cooling gas so that the third virtual line I3 contacts a second position P2 on the outer periphery of the heating object 2.

[0071] In some embodiments, the first imaginary line I1 may not be tangent to the first position P1 of the object to be heated 2. The second imaginary line I2 may not be tangent to the third position P3 of the object to be heated 2. The third imaginary line I3 may not be tangent to the second position P2 of the object to be heated 2.

[0072] In the second quadrant Q2, the gas supply pipe 3a ejects the cooling gas into the internal space 11 along the first axis L1, in a direction from the second quadrant Q2 to the third quadrant Q3. In the third quadrant Q3, the gas supply pipe 3b ejects the cooling gas into the internal space 11 along the second axis L2, in a direction from the third quadrant Q3 to the fourth quadrant Q4. In the fourth quadrant Q4, the gas supply pipe 3c ejects the cooling gas into the internal space 11 along the first axis L1, in a direction from the fourth quadrant Q4 to the first quadrant Q1. Therefore, as shown by arrow B, a counterclockwise swirling airflow is formed in the internal space 11. In other words, the gas supply pipes 3a and 3b eject the cooling gas into the internal space 11 so that the ejection directions of the cooling gas from the gas supply pipes 3a and 3b are the same rotational direction (counterclockwise).

[0073] In this embodiment, the same effects as in the first embodiment can be obtained. In addition, in this embodiment, the cooling gas ejected from the three gas supply pipes 3 a to 3 c forms a swirling airflow that swirls in the internal space 11. Therefore, the swirling airflow is more likely to be formed along the inner wall 12, and the object to be heated 2 can be uniformly cooled along the swirling direction of the swirling airflow.

[0074] 14 has the same configuration as the heating furnace 1E of the sixth embodiment, except for the following points: The same reference numerals are used to designate parts that overlap with the heating furnace 1E of the sixth embodiment, and detailed descriptions thereof will be omitted.

[0075] The heating furnace 1F has a gas supply pipe 3d in addition to the gas supply pipes 3a to 3c. A line along the ejection direction A4 of the cooling gas ejected from the gas supply pipe 3d is defined as a fourth imaginary line I4. The fourth imaginary line I4 is a line that is an imaginary extension of the axis of the gas supply pipe 3d. The fourth imaginary line I4 is parallel to the second axis L2 and perpendicular to the first axis L1. The fourth imaginary line I4 corresponds to a tangent to the object 2 to be heated.

[0076] 14 , the third position P3 and the fourth position P4 are located on opposite sides of the first axis L1 on the outer periphery of the object to be heated 2. The third position P3 is one of the intersections between the first axis L1 and the outer periphery of the object to be heated 2. The fourth position P4 is the other of the intersections between the first axis L1 and the outer periphery of the object to be heated 2.

[0077] In this embodiment, the gas supply pipe 3d ejects the cooling gas so that the fourth imaginary line I4 contacts a fourth position P4 on the outer periphery of the heating object 2. In some embodiments, the fourth imaginary line I4 does not need to contact the fourth position P4 of the heating object 2.

[0078] In the second quadrant Q2, the gas supply pipe 3a ejects the cooling gas into the internal space 11 along the first axis L1, in a direction from the second quadrant Q2 to the third quadrant Q3. In the third quadrant Q3, the gas supply pipe 3b ejects the cooling gas into the internal space 11 along the second axis L2, in a direction from the third quadrant Q3 to the fourth quadrant Q4. In the fourth quadrant Q4, the gas supply pipe 3c ejects the cooling gas into the internal space 11 along the first axis L1, in a direction from the fourth quadrant Q4 to the first quadrant Q1. In the first quadrant Q1, the gas supply pipe 3d ejects the cooling gas into the internal space 11 along the second axis L2, in a direction from the first quadrant Q1 to the second quadrant Q2. Therefore, as shown by arrow B, a counterclockwise swirling airflow is formed in the internal space 11. That is, the gas supply pipes 3a to 3d eject the cooling gas into the internal space 11 so that the ejection directions of the cooling gas from the gas supply pipes 3a to 3d are in the same rotational direction (counterclockwise).

[0079] In this embodiment, the same effects as in the sixth embodiment can be obtained. In addition, in this embodiment, the cooling gas ejected from the four gas supply pipes 3a to 3d forms a swirling airflow that swirls in the internal space 11. Therefore, the swirling airflow is more likely to be formed along the inner wall 12, and the object to be heated 2 can be uniformly cooled along the swirling direction of the swirling airflow.

[0080] The present disclosure is not limited to the above-described embodiments, and various modifications can be made within the scope of the present disclosure.

[0081] 15 , the container 10 may be provided with two gas exhaust pipes 4. One gas exhaust pipe 4 is provided at the bottom 13, and the other gas exhaust pipe 4 is provided at the top 14. The gas exhaust pipe 4 provided at the bottom 13 and the gas exhaust pipe 4 provided at the top 14 are located at the center of the container 10 in a plan view. In this case as well, a three-dimensional swirling airflow is formed in the internal space 11, and the entire object 2 to be heated can be uniformly cooled.

[0082] As shown in FIG. 1, the heat source 5 is provided separately from the container 10, but it may be provided integrally with the container 10.

[0083] The techniques shown in Figures 3, 4, 6 to 11, 13, 14, and / or 15 may be applied to a heating furnace 1D of the fifth embodiment shown in Figure 12. Furthermore, the techniques shown in Figures 3, 4, 6, 8 to 11, 12, and / or 15 may be applied to a heating furnace 1E of the sixth embodiment shown in Figure 13. Furthermore, the techniques shown in Figures 3, 4, 6, 8 to 11, 12, and / or 15 may be applied to a heating furnace 1F of the seventh embodiment shown in Figure 14.

[0084] DESCRIPTION OF SYMBOLS 1, 1A to 1F... Heating furnace 2... Heating object 3a, 3b, 3c, 3d... Gas supply pipe 4... Gas exhaust pipe 5... Heat source 6... Support 10... Container 11... Internal space 12... Inner wall 13... Bottom 14... Top 15a, 15b... Gas supply hole 16... Gas exhaust hole

Claims

1. A heating furnace comprising: a container having an internal space for placing an object to be heated and an inner wall surrounding said internal space; a plurality of gas supply pipes for supplying cooling gas to said internal space; and a gas discharge pipe for discharging said cooling gas from said internal space, wherein said plurality of gas supply pipes spray said cooling gas into said internal space such that the spray directions of said cooling gas from said plurality of gas supply pipes are in the same rotational direction.

2. A heating furnace as described in claim 1, wherein when the internal space is divided into four quadrants in a plan view by an arbitrary first axis passing through the center of the internal space and a second axis perpendicular to the first axis, the plurality of gas supply pipes eject the cooling gas into the internal space in different quadrants.

3. The heating furnace according to claim 2, wherein the plurality of gas supply pipes include at least a first gas supply pipe and a second gas supply pipe, and the first gas supply pipe and the second gas supply pipe eject the cooling gas into the internal space in quadrants that face each other across the center.

4. A heating furnace as described in claim 2 or 3, wherein the plurality of gas supply pipes include at least a first gas supply pipe and a second gas supply pipe, the outer periphery of the object to be heated has the first position and the second position located on opposite sides along the first axis, the direction of the cooling gas ejected from the first gas supply pipe is directed toward the first position, and the direction of the cooling gas ejected from the second gas supply pipe is directed toward the second position.

5. The heating furnace according to claim 4, wherein the first gas supply pipe and the second gas supply pipe eject cooling gas along the second axis, and when a line along the ejection direction of the cooling gas ejected from the first gas supply pipe is defined as a first imaginary line and a line along the ejection direction of the cooling gas ejected from the second gas supply pipe is defined as a second imaginary line, the distance along the first axis between the first imaginary line and the second imaginary line is equal to the distance along the first axis between the first position and the second position.

6. A heating furnace according to any one of claims 1 to 3, wherein the plurality of gas supply pipes include at least a first gas supply pipe and a second gas supply pipe, and the direction of the cooling gas ejected from the first gas supply pipe is parallel to the direction of the cooling gas ejected from the second gas supply pipe.

7. A heating furnace according to any one of claims 1 to 3, wherein the plurality of gas supply pipes include at least a first gas supply pipe and a second gas supply pipe, and the direction of the cooling gas ejected from the first gas supply pipe is non-parallel to the direction of the cooling gas ejected from the second gas supply pipe.

8. A heating furnace according to any one of claims 1 to 3, wherein the gas exhaust pipe is located at the center of the container in a plan view.

9. A heating furnace according to claim 8, wherein the gas exhaust pipe is provided at the bottom of the container.

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