Bonfire

Abstract

To provide a bonfire stand that reduces generated smoke and reduces the mass of combustion residue.SOLUTION: In a bonfire stand including a combustion chamber in which fuel is burned, a base on which the combustion chamber is placed, and a tray which is disposed inside the combustion chamber and on which the fuel is placed, the combustion chamber is an octagonal prism, one side surface of the octagonal prism is a floor surface, and a flame protrusion port for protruding a flame when the fuel is burned is provided on a ceiling surface facing the floor surface.SELECTED DRAWING: Figure 1

Description

[0001] The present invention relates to a fire pit. [Background technology]

[0002] With the recent boom in outdoor activities, open fires at campsites and other outdoor spots are generally prohibited, and instead, fire pits are used. Fire pits allow firewood and other materials to be burned away from the ground. This prevents the spread of fire to surrounding fallen leaves and twigs, avoids damage to plants and insects, and prevents the charcoal and ash remaining after combustion from polluting the soil, rivers, and oceans.

[0003] Patent Document 1 discloses a lightweight and portable fire pit as an example of such a fire pit. However, the fire pit disclosed in Patent Document 1 does not take into consideration the smoke generated, and does not mention the mass of residue remaining after combustion. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-75270 Summary of the Invention [Problem to be solved by the invention]

[0005] The object of the present invention is to provide a fire pit that reduces the amount of smoke produced and the mass of combustion residue. [Means for solving the problem]

[0006] The amount of smoke generated is related to the combustion temperature, and increases when the combustion temperature is low and incomplete combustion gases are included. Also, in an incomplete combustion atmosphere, some fuel remains during combustion, resulting in a large amount of combustion residue.

[0007] The inventors of the present invention have focused on reducing incomplete combustion gases and conducted extensive research. As a result, they have discovered that secondary combustion of incomplete combustion gases reduces smoke and the mass of combustion residues in a fire pit, leading to the completion of the present invention.

[0008] That is, the present invention is as follows. [1] A fire pit comprising a combustion chamber for burning fuel, a base for placing the combustion chamber, and a tray for placing the fuel inside the combustion chamber, The combustion chamber is an octagonal prism, one side of which serves as a floor, and a ceiling surface opposite to the floor surface is provided with a flame projection port for projecting a flame when the fuel is combusted. Bonfire pit. [2] A campfire stand as described in aspect [1], wherein at least two vertical surfaces that are not adjacent to the floor surface and the ceiling surface have multiple vertical secondary air inlet holes for ventilation. [3] A campfire stand as described in aspect [1] or [2], wherein the ceiling surface and the two upper inclined surfaces adjacent to the vertical surface have multiple upper inclined surface secondary air inlet holes for ventilation. [4] At least the top or bottom surface of the octagonal prism is open, according to aspect [3]. [Effects of the Invention]

[0009] The fire pit of the present invention has high combustion efficiency, reduces smoke generation, and reduces the mass of combustion residue. Therefore, the fire pit of the present invention produces little smoke during use, does not require effort to clean up, and is easy to use. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a perspective view of a fire pit according to one embodiment of the present invention. FIG. [Figure 2] FIG. 2 is a front view of a combustion chamber according to an embodiment of the present invention. [Figure 3] FIG. 2 is a right side view of a combustion chamber according to an embodiment of the present invention. [Figure 4] FIG. 2 is a plan view of a combustion chamber according to an embodiment of the present invention. [Figure 5] 1 is a photograph of the fire pit used in Example 1. [Figure 6] 1 is a photograph of the fire pit used in Comparative Example 1. [Figure 7] FIG. 2 is a diagram showing measurement points of combustion temperatures in Examples and Comparative Examples. DETAILED DESCRIPTION OF THE INVENTION

[0011] The following describes the fire pit of the present invention with reference to the drawings.

[0012] (fire pit) The fire pit of the present invention comprises a combustion chamber for burning fuel, a base on which the combustion chamber is placed, and a tray that is placed inside the combustion chamber and on which the fuel is placed.

[0013] 1 is a perspective view of a fire pit 500 according to one embodiment of the present invention. The fire pit 500 shown in Fig. 1 includes a combustion chamber 100 for burning fuel, a base 300 for placing the combustion chamber, and a tray 200 disposed inside the combustion chamber for placing fuel.

[0014] The combustion chamber of the fire pit of the present invention is an octagonal prism, which is composed of a ceiling surface, a floor surface, two vertical surfaces not adjacent to the ceiling surface or the floor surface, two upper inclined surfaces adjacent to the two vertical surfaces and the ceiling surface, and two lower inclined surfaces adjacent to the two vertical surfaces and the floor surface. One side of the octagonal prism is the floor surface of the combustion chamber, and the ceiling surface opposite the floor surface has a flame projection port for projecting flames when fuel burns.

[0015] 2 to 4 is an octagonal prism that is composed of a ceiling surface 11, a floor surface 12, two vertical surfaces 13 and 14 that are not adjacent to the ceiling surface 11 and the floor surface 12, two upper inclined surfaces 15 and 16 that are adjacent to the two vertical surfaces 13 and 14 and the ceiling surface 11, and two lower inclined surfaces 17 and 18 that are adjacent to the two vertical surfaces 13 and 14 and the floor surface 12. The combustion chamber 100 has floor surface 12, which is one side surface of the octagonal prism, as the floor surface, and the ceiling surface 11 that faces floor surface 12 has a flame projection port 19 for projecting a flame when fuel burns.

[0016] In one embodiment, the combustion chamber 100 has a ceiling surface 11 and a floor surface 12, two pairs of vertical surfaces 13 and 14, an upper inclined surface 15 and a lower inclined surface 18 facing each other, and an upper inclined surface 16 and a lower inclined surface 18 facing each other, all of which are parallel to each other.

[0017] As described above, in one embodiment, the combustion chamber 100 has a ceiling surface 11 and a floor surface 12, two pairs of vertical surfaces 13 and 14, an upper inclined surface 15 and a lower inclined surface 18 facing each other, and an upper inclined surface 16 and a lower inclined surface 18 facing each other, all of which are parallel to one another; however, the combustion chamber of the fire pit of the present invention is not limited to this.

[0018] (vertical plane) The two vertical surfaces of the fire pit that are not adjacent to the floor and ceiling surfaces of the fire pit of the present invention may be non-porous or may have multiple vertical secondary air inlet holes for ventilation. In the fire pit of the present invention, the vertical secondary air inlet holes are holes for introducing air from outside the combustion chamber into the combustion chamber. When the fire pit of the present invention has vertical secondary air inlet holes, fresh oxygen is introduced into the combustion chamber by taking in outside air from outside the combustion chamber, thereby allowing for secondary combustion of incompletely combusted gases, thereby reducing the generation of smoke and the mass of combustion residue.

[0019] As shown in the right side view of FIG. 3, a plurality of vertical secondary air introduction holes 20 are formed on the two vertical surfaces 13 and 14 of the combustion chamber 100 according to the embodiment shown in FIG.

[0020] In the fire pit of the present invention, the shape of the multiple vertical secondary air inlet holes formed on the two vertical surfaces is not particularly limited. Examples of the shape of the multiple vertical secondary air inlet holes formed on the two vertical surfaces include circles and polygons such as triangles and rectangles. The shapes of the multiple vertical secondary air inlet holes formed on the two vertical surfaces may be the same or different. For example, a mixture of circles and polygons may be used. In the present invention, a circular shape is acceptable because it is less likely to generate vortices and the introduction pressure of the secondary air is increased due to interference of circular waves.

[0021] In the fire pit of the present invention, the size of the multiple vertical secondary air inlet holes formed on the two vertical surfaces is not particularly limited. It is sufficient that the size allows sufficient secondary air to flow in. The multiple vertical secondary air inlet holes may be the same or different in size. For example, large and small secondary air inlet holes may be mixed.

[0022] In the fire pit of the present invention, the arrangement of the multiple vertical secondary air inlet holes formed on the two vertical surfaces is not particularly limited. The arrangement of the multiple vertical secondary air inlet holes may be regular or irregular. For example, the arrangement of the vertical secondary air inlet holes may be a mixture of regular and irregular parts. Since secondary air is introduced approximately uniformly and the interference of the introduced air waves occurs approximately uniformly, the multiple vertical secondary air inlet holes may be arranged at the same pitch.

[0023] In the combustion chamber 100 according to one embodiment, as shown in Fig. 3, the multiple vertical secondary air inlet holes 20 formed on the vertical surface 14 are all circular and arranged at the same pitch. In this way, in a fire pit where the vertical secondary air inlet holes 20 are circular and arranged at the same pitch, circular wave interference occurs almost uniformly, so the introduction pressure of the secondary air can be increased, and as a result, incomplete combustion gas can be efficiently subjected to secondary combustion, reducing smoke generation and the mass of combustion residue.

[0024] (Upper slope) The ceiling surface and the two upper inclined surfaces adjacent to the vertical surface of the fire pit of the present invention may be non-porous or may have multiple upper inclined surface secondary air inlet holes for ventilation. In the fire pit of the present invention, by providing secondary air inlet holes on the vertical surface and also on the upper inclined surface, the amount of air introduced can be increased, resulting in more effective secondary combustion of incomplete combustion gases, reducing smoke generation and the mass of combustion residue.

[0025] As shown in the right side view of FIG. 3, a plurality of upper inclined surface secondary air introduction holes 21 are formed in the two upper inclined surfaces 15 and 16 of the combustion chamber 100 according to the embodiment shown in FIG.

[0026] In the fire pit of the present invention, the shape of the plurality of upper inclined surface secondary air inlet holes formed on the two upper inclined surfaces is not particularly limited. The shape of the plurality of upper inclined surface secondary air inlet holes formed on the two upper inclined surfaces may be the same as the shape of the plurality of vertical surface secondary air inlet holes formed on the two vertical surfaces described above.

[0027] In the fire pit of the present invention, the size of the plurality of upper inclined surface secondary air inlet holes formed on the two upper inclined surfaces is not particularly limited. It is sufficient that the size allows sufficient secondary air to flow in, and it may be the same size as the plurality of vertical surface secondary air inlet holes formed on the two vertical surfaces described above.

[0028] In the fire pit of the present invention, the arrangement of the plurality of upper inclined surface secondary air inlet holes formed on the two upper inclined surfaces is not particularly limited. The arrangement of the plurality of upper inclined surface secondary air inlet holes may be the same as the arrangement of the plurality of vertical surface secondary air inlet holes formed on the two vertical surfaces described above.

[0029] The shape, size and arrangement of the upper inclined surface secondary air introduction holes and the above-mentioned vertical surface secondary air introduction holes may be the same or different.

[0030] In the combustion chamber 100 according to one embodiment shown in Figure 3, multiple upper inclined surface secondary air introduction holes 21 are formed on the upper inclined surfaces 15 and 16. The multiple upper inclined surface secondary air introduction holes 21 shown in Figure 3 are all diamond-shaped and arranged at the same pitch. In this way, in a fire pit in which the upper inclined surface secondary air introduction holes 21 are arranged at the same pitch, wave interference occurs approximately uniformly, making it possible to increase the introduction pressure of the secondary air. As a result, incomplete combustion gas can be efficiently subjected to secondary combustion, reducing smoke generation and the mass of combustion residue.

[0031] In the fire pit of the present invention, at least the top or bottom of the octagonal prism of the combustion chamber may be open. The opening may be only on the top, only on the bottom, or on both sides. Also, the entire top or bottom area may be open, or only a portion of the top or bottom area may be open.

[0032] When a portion of the top or bottom surface is open, the area through which the tray can be inserted or removed may be open. When a portion of the top or bottom surface is open, a secondary air introduction hole may be formed in the non-open area.

[0033] When the secondary air inlet holes are formed on the top or bottom surface, the shape, size, and arrangement of the secondary air inlet holes may be similar to those of the vertical surface secondary air inlet holes and upper inclined surface secondary air inlet holes described above.

[0034] If the top or bottom surface has an opening, the area of ​​the opening may be larger than the area of ​​the flame outlet. If the area of ​​the opening on the top or bottom surface is larger than the area of ​​the flame outlet, the amount of inflow air will be sufficiently large, improving combustion efficiency and allowing you to enjoy the performance of the flame.

[0035] The combustion chamber 100 in the fire pit according to one embodiment shown in Figure 3 is open on both the top surface 22 and the bottom surface 23. By opening both the top surface 22 and the bottom surface 23, the flame can be viewed directly, and the air heated inside the combustion chamber 100 flows out around the fire pit, making it easier to heat the surrounding atmosphere.

[0036] The metal used to make the combustion chamber of the fire pit of the present invention is not particularly limited. The metal used to make the combustion chamber may be, for example, iron, stainless steel, titanium, or an alloy thereof. Stainless steel provides a combustion chamber with excellent corrosion resistance and heat resistance. Iron may also be used when emphasis is placed on workability and cost.

[0037] The thickness of the metal material forming the combustion chamber is not particularly limited as long as it is thick enough to withstand thermal deformation. The thickness of the metal material forming the combustion chamber may be a thin plate, for example, 1.6 mm or less.

[0038] In the fire pit of the present invention, the size of the combustion chamber can be designed appropriately according to needs. For example, if it is used for family camping, it only needs to be small, and if it is used for group campfires, it can be medium to large.

[0039] In the fire pit of the present invention, the method for forming the combustion chamber is not particularly limited. As long as it can be formed into an octagonal prism shape, it can be fastened with bolts or processed by bending, for example.

[0040] (tray) The tray used in the fire pit of the present invention is placed inside the combustion chamber and serves to place fuel. The fire pit of the present invention burns the fuel placed on the tray inside the combustion chamber to create a fire.

[0041] 1 is a perspective view of a fire pit 500 according to one embodiment of the present invention. In the fire pit 500, the tray 200 is in surface contact with the lower inclined surfaces 17 and 18 of the combustion chamber 100 and is placed on the floor surface 12 of the combustion chamber 100 without being separated therefrom.

[0042] The shape of the tray is not particularly limited. It is sufficient if it has a substantially rectangular tray floor on which fuel is placed and four side surfaces connected to it. For example, the rectangular opening may be larger than the rectangular bottom surface. This allows the tray sides to be inclined.

[0043] The tray used in the present invention may have a ceiling surface connected to the four side surfaces. When the tray has a ceiling surface, the ceiling surface has an opening for ejecting a flame when the fuel burns.

[0044] The material of the tray of the fire pit of the present invention is not particularly limited. The material of the tray may be metal, for example, iron, stainless steel, titanium, or an alloy thereof. As with the combustion chamber described above, stainless steel provides a base with excellent corrosion resistance and heat resistance. Iron may also be used when emphasis is placed on processability and cost.

[0045] (pedestal) The base that constitutes the fire pit of the present invention is used to place the combustion chamber in the fire pit.

[0046] By placing the combustion chamber on the base, the combustion chamber is arranged in a state where it is raised above the installation surface of the lawn, etc. This makes it possible to prevent the lawn, etc. from being burned by the heat generated during combustion.

[0047] The shape and size of the base are not particularly limited as long as it can accommodate the combustion chamber. The material of the base of the fire pit of the present invention is also not particularly limited. The base material may be metal, such as iron, stainless steel, titanium, or an alloy thereof. As with the combustion chamber described above, stainless steel provides a base with excellent corrosion resistance and heat resistance. Iron may also be used when emphasis is placed on workability and cost.

[0048] In FIG. 1, which is a perspective view of the fire pit of the present invention, a base 300 has a combustion chamber 100 placed thereon. [Example]

[0049] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. [Example]

[0050] The combustion chamber shown in Figure 5 is an octagonal prism, and the vertical surfaces of the side of the octagonal prism that are not adjacent to the floor or ceiling do not have secondary air inlet holes, but are equipped with an outlet for projecting the flame onto the ceiling surface opposite the floor, and a campfire stand was used that is open on the entire top or bottom surface.

[0051] 2130g of a mixture of softwood and hardwood was prepared as fuel. The fuel was placed on a tray and ignited with a burner to create a bonfire. The mass was measured using a TASCO ELETRONIC CHARGING SCALE MODEL TA101FA / TA101FB.

[0052] <Evaluation method> The combustion temperature and combustion residue were evaluated by the following methods.

[0053] (Combustion temperature) The temperatures at seven points a to g shown in Figure 7 15 minutes after ignition were measured using a temperature measuring device. The measurement points are indicated by the arrowheads shown in a to g in Figure 7. The temperature measuring device used was an IR THERMOMETER ROOK model 400 / 600SP manufactured by Erickhill. The results are shown in Table 1.

[0054] (combustion residue) The residue was collected 30 minutes after ignition, and the mass of the combustion residue was measured using the mass measuring device described above. The obtained results were used to calculate the residue rate using the following formula. The combustion mass and residue rate are shown in Table 1. Residue rate (%) = (mass of combustion residue / mass before combustion) x 100

[0055] The state of the combustion residue was also visually observed and the evaluation criteria are shown below. Excellent: The entire fuel is charcoal or ash Good: 80% or more of the fuel surface is charcoal or ash Not allowed: Some fuel remains.

[0056] [Table 1] [Example]

[0057] A bonfire was started in the same manner as in Example 1, except that the combustion chamber was an octagonal prism and a bonfire stand was used that had a secondary air inlet hole on the vertical surface of the side of the octagonal prism that was not adjacent to the floor or ceiling. Various measurements and observations were made in the same manner as in Example 1. The results are shown in Table 1.

[0058] <Comparative Example 1> Except for using a fire pit whose combustion chamber shown in Figure 6 was cylindrical, had no flame outlet, had a secondary air inlet at the top of the cylinder, and had a part of the top or bottom open, a fire was started in the same manner as in Example 1, and various measurements and observations were carried out in the same manner as in Example 1. The results are shown in Table 1.

[0059] <Consideration> The results in Table 1 show that Examples 1 and 2, which had an octagonal prism-shaped combustion chamber, had higher combustion temperatures and generated less smoke than Comparative Example 1, which had a cylindrical combustion chamber. Examples 1 and 2 also generated less combustion residue than Comparative Example 1.

[0060] From the above results, it can be seen that campfire stoves with combustion chambers that are octagonal pillars have high combustion efficiency. [Explanation of symbols]

[0061] 100 combustion chamber 200 trays 300 pedestal 500 fire pit 11 Ceiling surface 12 Floor 13 Left vertical plane 14 Right vertical plane 15 Upper left slope 16 Upper right slope 17 Lower left slope 18 Lower right slope 19 Flame outlet 20 Right side secondary air intake 21 Secondary air intake on upper right inclined surface 22 Top side 23 bottom abcdefg Arrows indicating combustion temperature measurement points

Claims

1. A fire pit comprising a combustion chamber for burning fuel, a base for placing the combustion chamber, and a tray for placing the fuel inside the combustion chamber, The combustion chamber is an octagonal prism, one side of which serves as a floor, and a ceiling surface opposite to the floor surface is provided with a flame projection port for projecting a flame when the fuel is combusted. Bonfire pit.

2. The fire pit according to claim 1, wherein at least two vertical surfaces that are not adjacent to the floor surface and the ceiling surface have a plurality of vertical secondary air inlet holes for ventilation.

3. The fire pit according to claim 1 or 2, wherein the ceiling surface and the two upper inclined surfaces adjacent to the vertical surface have a plurality of upper inclined surface secondary air inlet holes for ventilation.

4. The fire pit according to claim 3, wherein at least the top or bottom surface of the octagonal prism is open.

Images