Combustion device

Abstract

The present invention provides a combustion device that has a primary combustion chamber, a secondary combustion space located above the primary combustion chamber, and a tertiary combustion space located above the secondary combustion space, and is capable of efficiently supplying tertiary combustion air to the tertiary combustion space. [Solution] In the combustion device 1, the opening at the upper end of the second inner cylinder 5, whose inner circumference is connected to the air intake portion 15 of the outer cylinder 4, is a third intake port 5a for taking in tertiary combustion air from the inner circumference of the inner cylinder 3, and the inner circumference of the second inner cylinder 5 is a passage for tertiary combustion air. In addition, in the combustion device 1, the second intake port 19b for taking in secondary combustion air from the inner circumference of the inner cylinder 3 is connected to an air passage 22 between the outer surface of the inner cylinder 3 and the inner surface of the outer cylinder 4, and the passage for secondary combustion air and the passage for tertiary combustion air are separate passages.

Description

Technical Field

[0001] The present invention relates to a combustion device for burning solid fuels such as wood pellets.

Background Art

[0002] Conventionally, a combustion device for burning wood chips has been known (see, for example, Patent Document 1). The combustion device described in Patent Document 1 includes a main body portion in which a first combustion chamber, a second combustion chamber disposed above the first combustion chamber, and a third combustion chamber disposed above the second combustion chamber are formed inside. In the combustion device described in Patent Document 1, a secondary combustion air supply means is constituted by a flow passage formed in the inner wall of the main body portion and an outlet formed in the lower part of the second combustion chamber, and secondary combustion air is supplied from the outer peripheral side of the second combustion chamber to the inner peripheral side of the second combustion chamber by the secondary combustion air supply means. Further, in this combustion device, a tertiary combustion air supply means is constituted by a flow passage formed in the inner wall of the main body portion and an outlet formed in the upper part of the second combustion chamber, and tertiary combustion air is supplied from the outer peripheral side of the third combustion chamber to the inner peripheral side of the third combustion chamber by the tertiary combustion air supply means.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The inventor of the present application has developed a combustion device in which a primary combustion chamber, a secondary combustion space disposed above the primary combustion chamber for burning combustion gas generated in the primary combustion chamber, and a tertiary combustion space disposed above the secondary combustion space for burning combustion gas generated in the secondary combustion space are formed inside. In this combustion device, in order to perform the tertiary combustion in the tertiary combustion space more effectively, it is preferable that the tertiary combustion air is efficiently supplied to the tertiary combustion space.

[0005] Therefore, the object of the present invention is to provide a combustion device in which a primary combustion chamber, a secondary combustion space located above the primary combustion chamber, and a tertiary combustion space located above the secondary combustion space are formed inside, and which is capable of efficiently supplying tertiary combustion air to the tertiary combustion space. [Means for solving the problem]

[0006] To solve the above problems, the combustion apparatus of the present invention comprises a bottomed cylindrical inner cylinder portion in which solid fuel is contained on the inner circumference side, a cylindrical outer cylinder portion in which the inner cylinder portion is contained on the inner circumference side, and a cylindrical second inner cylinder portion arranged on the inner circumference side of the inner cylinder portion. The axial directions of the inner cylinder portion, the outer cylinder portion, and the second inner cylinder portion coincide with the vertical direction, the lower end of the outer cylinder portion is an air intake portion in which an air intake port is formed, the bottom of the inner cylinder portion is positioned above the air intake portion, an air passage is formed between the outer circumferential surface of the inner cylinder portion and the inner circumferential surface of the outer cylinder portion, the lower end of the air passage is connected to the air intake portion, a first intake port is formed at the lower end of the inner cylinder portion, which is an intake port for taking in primary combustion air on the inner circumference side of the inner cylinder portion, the first intake port is connected to at least one of the air intake portion and the air passage, the lower end of the second inner cylinder portion is fixed to the bottom of the inner cylinder portion, the inner circumference side of the second inner cylinder portion is connected to the air intake portion, and the inner cylinder A primary combustion chamber for burning solid fuel is formed on the inner circumference side of the part and on the outer circumference side of the second inner cylinder part. A second intake port is formed in the part of the inner cylinder part above the primary fuel chamber, which is an intake port for taking in secondary combustion air on the inner circumference side of the inner cylinder part. The second intake port is connected to an air passage. The upper end of the second inner cylinder part is positioned below the upper end of the inner cylinder part and above the second intake port. The opening at the upper end of the second inner cylinder part is a third intake port for taking in tertiary combustion air on the inner circumference side of the inner cylinder part. The part on the inner circumference side of the inner cylinder part and on the outer circumference side of the second inner cylinder part above the second intake port and below the upper end of the second inner cylinder part is a secondary combustion space for burning combustion gases generated in the primary combustion chamber. The part on the inner circumference side of the inner cylinder part above the upper end of the second inner cylinder part is a tertiary combustion space for burning combustion gases generated in the secondary combustion space.

[0007] In the combustion apparatus of the present invention, the opening at the upper end of the second inner cylinder, whose inner circumference is connected to the air intake of the outer cylinder, serves as a third intake port for taking in tertiary combustion air to the inner circumference of the inner cylinder, and the inner circumference of the second inner cylinder serves as a passage for tertiary combustion air. Furthermore, in the present invention, the second intake port for taking in secondary combustion air to the inner circumference of the inner cylinder is connected to the air passage between the outer surface of the inner cylinder and the inner surface of the outer cylinder, and the passage for secondary combustion air and the passage for tertiary combustion air are separate passages. Therefore, in the present invention, it is possible to supply tertiary combustion air to the tertiary combustion space without being affected by the amount of secondary combustion air supplied. Consequently, in the present invention, it is possible to efficiently supply tertiary combustion air to the tertiary combustion space.

[0008] Furthermore, in the present invention, since the primary combustion chamber and the secondary combustion space are formed on the inner circumference side of the inner cylinder and on the outer circumference side of the second inner cylinder, it becomes possible to heat the tertiary combustion air on the inner circumference side of the second inner cylinder to a higher temperature and effectively generate an upward airflow of tertiary combustion air on the inner circumference side of the second inner cylinder. Therefore, in the present invention, it becomes possible to supply more tertiary combustion air to the tertiary combustion space from the third intake port at the upper end of the second inner cylinder.

[0009] In the present invention, it is preferable that the combustion device includes a lid attached to the upper end of the second inner cylinder portion, which guides the tertiary combustion air to the outer circumference of the second inner cylinder portion. With this configuration, it becomes possible to diffuse the tertiary combustion air in the tertiary combustion space. Therefore, it becomes possible to perform tertiary combustion in the tertiary combustion space efficiently.

[0010] In the present invention, it is preferable that a fourth intake port for taking in air for quaternary combustion is formed above the tertiary combustion space, and the portion above the tertiary combustion space is a quaternary combustion space for burning the combustion gases generated in the tertiary combustion space. With this configuration, it is possible to raise the temperature of the upper end of the combustion device even if the height of the combustion device is increased. Therefore, for example, by installing a trivet above the outer cylindrical part, it becomes possible to grill or boil food in a combustion device of an appropriate height.

[0011] In the present invention, it is preferable that the upper end of the inner cylinder portion is positioned lower than the upper end of the outer cylinder portion, and that the upper end of the air passage is the fourth intake port. With this configuration, it is not necessary to form the fourth intake port in the inner cylinder portion, thus simplifying the structure of the inner cylinder portion.

[0012] In the present invention, the combustion device preferably includes a frame-shaped second lid positioned above the fourth intake port and guiding the quaternary combustion air to the inner circumference of the outer cylinder, with the area above the second lid and on the inner circumference of the outer cylinder being the quaternary combustion space. With this configuration, it becomes possible to diffuse the quaternary combustion air in the quaternary combustion space. Therefore, it becomes possible to efficiently perform quaternary combustion in the quaternary combustion space. [Effects of the Invention]

[0013] As described above, in the present invention, in a combustion device having a primary combustion chamber, a secondary combustion space located above the primary combustion chamber, and a tertiary combustion space located above the secondary combustion space, it becomes possible to efficiently supply tertiary combustion air to the tertiary combustion space. [Brief explanation of the drawing]

[0014] [Figure 1] This is a cross-sectional view of a combustion device according to an embodiment of the present invention. [Figure 2] Figure 1 is a side view of the combustion apparatus shown. [Figure 3] Figure 1 is a plan view of the second lid. [Figure 4] (A) is a plan view of the inner cylinder and the second inner cylinder shown in Figure 1, and (B) is a side view of the inner cylinder shown in Figure 1. [Modes for carrying out the invention]

[0015] Embodiments of the present invention will be described below with reference to the drawings.

[0016] (Configuration of the combustion device) Figure 1 is a cross-sectional view of a combustion device 1 according to an embodiment of the present invention. Figure 2 is a side view of the combustion device 1 shown in Figure 1. Figure 3 is a plan view of the second lid portion 7 shown in Figure 1. Figure 4(A) is a plan view of the inner cylinder portion 3 and the second inner cylinder portion 5 shown in Figure 1, and Figure 4(B) is a side view of the inner cylinder portion 3 shown in Figure 1.

[0017] The combustion device 1 in this embodiment is a device for burning wood pellets 2, which are a solid fuel. The combustion device 1 is made of steel plate. The wood pellets 2 are formed in a cylindrical shape, for example, with a diameter of 6 mm. The combustion device 1 comprises a cylindrical inner cylinder portion 3 in which the wood pellets 2 are housed on the inner circumference, a cylindrical outer cylinder portion 4 in which the inner cylinder portion 3 is housed on the inner circumference, and a cylindrical second inner cylinder portion 5 arranged on the inner circumference of the inner cylinder portion 3. The axial directions of the cylindrical inner cylinder portion 3, outer cylinder portion 4, and second inner cylinder portion 5 coincide with the vertical direction.

[0018] The inner cylinder portion 3 and the outer cylinder portion 4 are formed in a rectangular tubular shape. The second inner cylinder portion 5 is formed in a cylindrical shape. The axes of the inner cylinder portion 3, the outer cylinder portion 4, and the second inner cylinder portion 5 coincide. The axial length (height) of the inner cylinder portion 3 is longer than the axial length of the second inner cylinder portion 5. The axial length of the outer cylinder portion 4 is longer than the axial length of the inner cylinder portion 3. The combustion device 1 also includes a lid portion 6 positioned above the second inner cylinder portion 5, a second lid portion 7 positioned above the inner cylinder portion 3, a trivet portion 8 positioned above the outer cylinder portion 4, a support member 9 supporting the trivet portion 8, and a base 10 positioned below the bottom member 18, which will be described later and constitute a part of the inner cylinder portion 3. Note that the trivet portion 8 and the support member 9 are not shown in Figure 1.

[0019] The outer cylindrical portion 4 is formed in a bottomed rectangular cylindrical shape with an open upper end. The outer cylindrical portion 4 is composed of a flat bottom member 13 that is the bottom of the outer cylindrical portion 4 and a rectangular cylindrical tubular member 14 that rises upward from the bottom member 13. The outer shape of the tubular member 14 when viewed from the vertical direction is square. When viewed from the vertical direction, the outer shape of the bottom member 13 is larger than the outer shape of the tubular member 14. An air intake 14a is formed at the lower end of the tubular member 14. That is, an intake 14a is formed at the lower end of the outer cylindrical portion 4. The intake 14a is formed in each of the four side faces of the tubular member 14 having a rectangular cylindrical shape. The intake 14a is a rectangular notch cut upward from the lower end of the tubular member 14. The lower end portion of the outer cylindrical portion 4 is an air intake portion 15 where the intake 14a is formed.

[0020] The base 10 is composed of a flat top plate 16 and legs 17 extending downward from the top plate 16. The base 10 is placed on the bottom member 13. The base 10 is arranged inside the air intake portion 15. A large number of through holes penetrating the top plate 16 in the vertical direction are formed in the top plate 16, and the air taken in through the intake 14a can pass through the top plate 16 from the lower side to the upper side. The support member 9 is fixed to the outer peripheral surface of the upper end portion of the tubular member 14. The trivet 8 is fixed to the upper end portion of the support member 9.

[0021] The inner cylindrical portion 3 is formed in a bottomed rectangular cylindrical shape with an open upper end. The inner cylindrical portion 3 includes a flat bottom member 18 that is the bottom of the inner cylindrical portion 3 and a rectangular cylindrical tubular member 19 that rises upward from the bottom member 18. Further, the inner cylindrical portion 3 includes four legs 20 extending downward from the lower end portion of the tubular member 19. The inner cylindrical portion 3 of this embodiment is composed of the bottom member 18, the tubular member 19, and the four legs 20. The inner cylindrical portion 3 is placed on the bottom member 13. The upper end of the inner cylindrical portion 3 is arranged lower than the upper end of the outer cylindrical portion 4. In FIG. 1, the illustration of the legs 20 is omitted.

[0022] When viewed from the up-and-down direction, the outer shape of the bottom member 18 and the outer shape of the cylindrical member 19 are square. When viewed from the up-and-down direction, the outer shape of the bottom member 18 and the outer shape of the cylindrical member 19 are equal. The four side surfaces of the cylindrical member 19 having a square cylindrical shape are parallel to the four side surfaces of the cylindrical member 14 having a square cylindrical shape. The leg portions 20 extend downward from the four corners of the lower end portion of the cylindrical member 19. The lower ends of the leg portions 20 are in contact with the upper surface of the bottom member 13. The bottom member 18 is disposed above the air intake portion 15. The lower side of the bottom member 18 forms part of the air intake portion 15. An air flow path 22, which is an air flow path, is formed between the cylindrical member 19 and the cylindrical member 14. That is, an air flow path 22 is formed between the outer peripheral surface of the inner cylindrical portion 3 and the inner peripheral surface of the outer cylindrical portion 4. The lower end of the air flow path 22 is connected to the air intake portion 15.

[0023] A first intake port 18a, which is an intake port for taking in primary combustion air on the inner peripheral side of the inner cylindrical portion 3, is formed in the bottom member 18. Also, a first intake port 19a, which is an intake port for taking in primary combustion air on the inner peripheral side of the inner cylindrical portion 3, is formed at the lower end portion of the cylindrical member 19. That is, at the lower end portion of the inner cylindrical portion 3, first intake ports 18a and 19a for taking in primary combustion air on the inner peripheral side of the inner cylindrical portion 3 are formed. In FIG. 1, the illustration of the first intake port 18a is omitted.

[0024] A plurality (a large number) of the first intake ports 18a are formed in the bottom member 18. A plurality of the first intake ports 19a are formed in each of the four side surfaces of the cylindrical member 19. The first intake port 18a is a through hole that penetrates the bottom member 18 in the up-and-down direction. The first intake port 19a is a through hole that penetrates the cylindrical member 19 in the horizontal direction. The first intake port 18a communicates with the air intake portion 15. The first intake port 19a communicates with the air flow path 22. That is, the first intake ports 18a and 19a communicate with at least one of the air intake portion 15 and the air flow path 22.

[0025] The second inner cylinder portion 5 is formed in a cylindrical shape with openings at both the upper and lower ends. The lower end of the second inner cylinder portion 5 is fixed to the bottom member 18. Specifically, the lower end of the second inner cylinder portion 5 is fixed to a through hole formed in the center of the bottom member 18. The inner circumference of the second inner cylinder portion 5 is connected to the air intake portion 15. The upper end of the second inner cylinder portion 5 is positioned below the upper end of the inner cylinder portion 3.

[0026] A primary combustion chamber 23 for burning wood pellets 2 is formed on the inner circumference side of the inner cylindrical portion 3 and on the outer circumference side of the second inner cylindrical portion 5. Specifically, the primary combustion chamber 23 is formed on the upper side of the bottom member 18, on the inner circumference side of the lower portion of the cylindrical member 19, and on the outer circumference side of the lower portion of the second inner cylindrical portion 5. Wood pellets 2 are contained in the primary combustion chamber 23. Wood pellets 2 are supplied to the primary combustion chamber 23 from the upper side of the primary combustion chamber 23 by the user of the combustion device 1. In the primary combustion chamber 23, the wood pellets 2 are primarily combusted using primary combustion air taken in from the first intake ports 18a and 19a.

[0027] In the portion of the cylindrical member 19 above the primary combustion chamber 23, a second intake port 19b is formed, which is an intake port for taking in secondary combustion air on the inner circumference side of the inner cylindrical portion 3. In other words, a second intake port 19b is formed in the portion of the inner cylindrical portion 3 above the primary combustion chamber 23. Multiple second intake ports 19b are formed on each of the four side surfaces of the cylindrical member 19. The second intake port 19b is a through-hole that penetrates the cylindrical member 19 in the horizontal direction. The second intake port 19b is connected to the air passage 22. The number of second intake ports 19b formed in the cylindrical member 19 is greater than the number of first intake ports 19a formed in the cylindrical member 19.

[0028] As described above, the upper end of the second inner cylinder 5 is positioned below the upper end of the inner cylinder 3. Also, the upper end of the second inner cylinder 5 is positioned above the second intake port 19b. The opening at the upper end of the second inner cylinder 5 is the third intake port 5a, which is an intake port for taking in tertiary combustion air to the inner circumference of the inner cylinder 3. The lid 6 is attached to the upper end of the second inner cylinder 5. The lid 6 comprises a flat top plate 24 and a plurality of legs 25 connecting the top plate 24 to the upper end of the second inner cylinder 5. The top plate 24 is positioned above the third intake port 5a with a gap between it and the third intake port 5a in the vertical direction. The lid 6 serves to guide the tertiary combustion air taken in from the third intake port 5a to the outer circumference of the second inner cylinder 5.

[0029] As described above, the upper end of the inner cylinder portion 3 is positioned below the upper end of the outer cylinder portion 4, and the upper end of the air passage 22 is positioned below the upper end of the outer cylinder portion 4. The upper end of the air passage 22 is the fourth intake port 26, which is an intake port for taking in air for quaternary combustion. The second lid portion 7 is positioned above the fourth intake port 26. The second lid portion 7 is formed in a frame shape, and the inner circumference of the second lid portion 7 is open. In this embodiment, a square-shaped opening 7a is formed on the inner circumference of the second lid portion 7. When viewed from above or below, the outer shape of the second lid portion 7 is a square shape which is approximately the same as the shape of the inner circumference of the cylinder member 14. The second lid portion 7 is placed on a mounting member 27 which is fixed to the inner circumference of the cylinder member 14.

[0030] The second lid portion 7 is composed of four flat plate portions 7b. The flat plate portions 7b are inclined downwards toward the outer circumference of the second lid portion 7, and in the longitudinal cross-section of the second lid portion 7, the side portions of the second lid portion 7 are inclined downwards toward the outer circumference of the second lid portion 7 (see Figure 1). The lower end (outer circumference end) of the flat plate portions 7b is located at approximately the same position as the upper end of the inner cylinder portion 3 in the vertical direction. The upper end of the flat plate portions 7b (i.e., the edge of the opening 7a) is located on the inner circumference side of the inner circumference surface of the cylinder member 19. The second lid portion 7 serves the function of guiding the air for quaternary combustion to the inner circumference side of the outer cylinder portion 4.

[0031] In this embodiment, the portion on the inner circumference of the inner cylinder portion 3 and the outer circumference of the second inner cylinder portion 5, above the second intake port 19b and below the upper end of the second inner cylinder portion 5, forms a secondary combustion space 28 for burning the combustion gases generated in the primary combustion chamber 23. Secondary combustion air is drawn into the secondary combustion space 28 from the second intake port 19b. Furthermore, the portion on the inner circumference of the inner cylinder portion 3, above the upper end of the second inner cylinder portion 5, forms a tertiary combustion space 29 for burning the combustion gases generated in the secondary combustion space 28. Tertiary combustion air is drawn into the tertiary combustion space 29 from the third intake port 5a. The tertiary combustion space 29 is formed below the upper end of the inner cylinder portion 3.

[0032] Furthermore, the area above the second lid 7 and on the inner circumference of the outer cylindrical portion 4 is a quaternary combustion space 30 for burning the combustion gases generated in the tertiary combustion space 29. In other words, the portion above the tertiary combustion space 29 is a quaternary combustion space 30 for burning the combustion gases generated in the tertiary combustion space 29. Quaternary combustion air is drawn into the quaternary combustion space 30 from the fourth intake port 26. The fourth intake port 26 is formed above the tertiary combustion space 29.

[0033] (Main effects of this form) As explained above, in this embodiment, the inner circumference of the second inner cylinder 5 leading to the air intake section 15 serves as the passage for tertiary combustion air. Furthermore, in this embodiment, the second intake port 19b for taking in secondary combustion air is connected to the air passage 22, and the passages for secondary combustion air and tertiary combustion air are separate passages. Therefore, in this embodiment, it is possible to supply tertiary combustion air to the tertiary combustion space 29 without being affected by the supply amount of secondary combustion air, and as a result, it is possible to efficiently supply tertiary combustion air to the tertiary combustion space 29.

[0034] In this embodiment, the primary combustion chamber 23 and the secondary combustion space 28 are formed on the inner circumference side of the inner cylinder portion 3 and on the outer circumference side of the second inner cylinder portion 5. Therefore, in this embodiment, it is possible to heat the tertiary combustion air on the inner circumference side of the second inner cylinder portion 5 to a higher temperature, thereby effectively generating an upward airflow of tertiary combustion air on the inner circumference side of the second inner cylinder portion 5. Consequently, in this embodiment, it is possible to supply more tertiary combustion air to the tertiary combustion space 29 from the third intake port 5a at the upper end of the second inner cylinder portion 5.

[0035] In this embodiment, a lid portion 6 that guides the tertiary combustion air to the outer circumference of the second inner cylindrical portion 5 is attached to the upper end of the second inner cylindrical portion 5. Therefore, in this embodiment, it becomes possible to diffuse the tertiary combustion air in the tertiary combustion space 29, and as a result, it becomes possible to perform tertiary combustion in the tertiary combustion space 29 efficiently.

[0036] In this embodiment, a quaternary combustion space 30 is formed above the tertiary combustion space 29. Therefore, in this embodiment, even if the height of the combustion device 1 is increased, it is possible to raise the temperature of the upper end of the combustion device 1. Accordingly, by installing a trivet 8 on the upper side of the outer cylindrical part 4 as in this embodiment, it becomes possible to grill or boil food in a combustion device 1 of an appropriate height. In addition, in this embodiment, the upper end of the air passage 22 is the fourth intake port 26, and there is no need to form the fourth intake port 26 in the inner cylindrical part 3. Therefore, in this embodiment, it is possible to simplify the configuration of the inner cylindrical part 3.

[0037] In this embodiment, the area above the frame-shaped second lid 7, which guides the air for quaternary combustion to the inner circumference of the outer cylinder 4, and the inner circumference of the outer cylinder 4, forms the quaternary combustion space 30. Therefore, in this embodiment, it is possible to diffuse the air for quaternary combustion in the quaternary combustion space 30. Consequently, in this embodiment, it is possible to efficiently perform quaternary combustion in the quaternary combustion space 30. Furthermore, in this embodiment, in the vertical cross-section of the second lid 7, the side surface of the second lid 7 is inclined downwards as it approaches the outer circumference of the second lid 7, making it possible to efficiently guide the air for quaternary combustion to the inner circumference of the outer cylinder 4.

[0038] (Other embodiments) In the above-described configuration, the second lid portion 7 may be formed in the shape of a flat plate with the vertical direction as the thickness direction. Also, in the above-described configuration, the combustion device 1 does not have to be equipped with the second lid portion 7. In this case, for example, instead of the fourth intake port 26, a fourth intake port may be formed in the portion of the cylindrical member 19 above the tertiary combustion space 29, penetrating the cylindrical member 19 horizontally and leading to the air passage 22. In this case, the axial length of the cylindrical member 19 is longer than in the above-described configuration. Also, in this case, the portion of the inner circumference of the inner cylindrical portion 3 above the fourth intake port becomes the quaternary combustion space 30, and quaternary combustion air is taken into the quaternary combustion space 30 from the fourth intake port formed in the cylindrical member 19.

[0039] In the above-described embodiment, the inner cylindrical portion 3 may be formed in a cylindrical shape other than a rectangular cylindrical shape, such as a cylindrical shape. Similarly, the outer cylindrical portion 4 may be formed in a cylindrical shape other than a rectangular cylindrical shape, such as a cylindrical shape. Furthermore, in the above-described embodiment, the second inner cylindrical portion 5 may be formed in a cylindrical shape other than a rectangular cylindrical shape, such as a rectangular cylindrical shape. Also, in the above-described embodiment, the axis of the inner cylindrical portion 3 and the axis of the outer cylindrical portion 4 do not have to coincide, and the axis of the inner cylindrical portion 3 and the axis of the second inner cylindrical portion 5 do not have to coincide.

[0040] In the above-described configuration, the combustion device 1 does not necessarily have to have a quaternary combustion space 30. Also, in the above-described configuration, the combustion device 1 does not necessarily have to have a lid 6. Furthermore, the combustion device 1 does not necessarily have to have a trivet 8 and a support member 9, nor does it necessarily have to have a stand 10. Moreover, in the above-described configuration, the solid fuel burned in the combustion device 1 may be a solid fuel other than wood pellets, such as wood chips. [Explanation of Symbols]

[0041] 1. Combustion device 2. Wood pellets (solid fuel) 3 Inner cylinder part 4 Outer cylinder part 5 Second inner cylinder part 5a Third intake port 6 Lid 7 Second lid part 14a Intake 15 Air intake section 18. Bottom component (bottom of the inner cylindrical part) 18a, 19a First intake port 19b Second intake port 22 Airflow channels 23 Primary Combustion Chamber 26 Fourth intake port 28 Secondary combustion space 29. Tertiary combustion space 30. Quadratic combustion space

Claims

1. It comprises a bottomed cylindrical inner cylinder portion in which solid fuel is housed on the inner circumference, a cylindrical outer cylinder portion in which the inner cylinder portion is housed on the inner circumference, and a cylindrical second inner cylinder portion arranged on the inner circumference of the inner cylinder portion. The axial directions of the inner cylinder portion, the outer cylinder portion, and the second inner cylinder portion coincide with the vertical direction. The lower end of the outer cylindrical portion is an air intake section where an air intake port is formed. The bottom of the inner cylindrical portion is positioned above the air intake portion. An air passage, which is an airflow channel, is formed between the outer circumferential surface of the inner cylinder and the inner circumferential surface of the outer cylinder. The lower end of the air passage is connected to the air intake section. At the lower end of the inner cylindrical portion, a first intake port is formed on the inner circumference side of the inner cylindrical portion, which is an intake port for taking in primary combustion air. The first intake port is connected to at least one of the air intake section and the air passage, The lower end of the second inner cylinder portion is fixed to the bottom of the inner cylinder portion. The inner circumference of the second inner cylinder portion is connected to the air intake portion, A primary combustion chamber for burning the solid fuel is formed on the inner circumference side of the inner cylinder portion and on the outer circumference side of the second inner cylinder portion. In the portion of the inner cylinder above the primary fuel chamber, a second intake port is formed on the inner circumference side of the inner cylinder, which is an intake port for taking in secondary combustion air. The second intake port is connected to the air passage, The upper end of the second inner cylinder portion is positioned below the upper end of the inner cylinder portion and above the second intake port. The opening at the upper end of the second inner cylinder portion is a third intake port, which is an intake port for taking in tertiary combustion air on the inner circumference side of the inner cylinder portion. The portion on the inner circumference of the inner cylinder and the outer circumference of the second inner cylinder, above the second intake port and below the upper end of the second inner cylinder, serves as a secondary combustion space for burning the combustion gases generated in the primary combustion chamber. The combustion apparatus is characterized in that the portion of the inner circumference of the inner cylinder portion above the upper end of the second inner cylinder portion is a tertiary combustion space for burning the combustion gas generated in the secondary combustion space.

2. The combustion apparatus according to claim 1, further comprising a lid attached to the upper end of the second inner cylinder portion, which guides the tertiary combustion air to the outer circumference of the second inner cylinder portion.

3. A fourth intake port, which is an intake port for taking in air for quaternary combustion, is formed above the tertiary combustion space. The combustion apparatus according to claim 1 or 2, characterized in that the portion above the tertiary combustion space is a quaternary combustion space for burning the combustion gas generated in the tertiary combustion space.

4. The upper end of the inner cylindrical portion is positioned lower than the upper end of the outer cylindrical portion. The combustion apparatus according to claim 3, characterized in that the upper end of the air passage is the fourth intake port.

5. It is provided with a frame-shaped second lid portion positioned above the fourth intake port and guiding the quaternary combustion air to the inner circumference of the outer cylindrical portion, The combustion apparatus according to claim 4, characterized in that the upper side of the second lid and the inner circumference side of the outer cylindrical portion form the quaternary combustion space.

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