JP2024074722A - Wood/pellet dual-use stove, pellet box, and sauna room structure - Google Patents

Abstract

To provide a dual-use firewood/pellet stove that has high combustion efficiency and is suitable for use in saunas during outdoor leisure activities.
[Solution] The wood/pellet dual-use stove is equipped with a supply section which supplies fuel and air for natural combustion, a main combustion chamber which is connected to the supply section and where combustion takes place, an exhaust section, and an attachment pellet box 10 which can be attached to the supply section and stores, supplies, and burns pellet fuel. The pellet box 10 is equipped with a storage section which stores pellet fuel, a pellet quantity adjustment means 3 which adjusts the amount of pellet fuel supplied by natural fall from the storage section 2, an air intake 4, and a combustion section which is connected to the main combustion chamber and where pellet fuel is burned by air intake from the air intake 4. It is also equipped with secondary pellet quantity adjustment means 6 which secondarily adjusts the amount of pellets which have naturally fallen below the pellet quantity adjustment means 3, and below that an air intake amount adjustment means 8 which adjusts the amount of air intake from the air intake 4.
[Selected figure] Figure 3

Description

The present invention relates to a firewood/pellet stove, a pellet box, and a sauna room structure, and in particular to a firewood/pellet stove that can use both firewood and pellet fuels and can be used without any power source or electricity.

A pellet stove is a stove that uses wood pellets (hereafter simply referred to as "pellets"), which are made by compressing and molding wood and other raw materials into a certain shape, as fuel. The carbon dioxide generated by burning pellets is absorbed from the atmosphere during the tree growth process, so it does not affect the carbon dioxide concentration in the atmosphere and is so-called carbon neutral. Pellets also have the advantages of being easier to burn than firewood because they contain less moisture, have a longer burn time, and the amount fed in is easier to adjust. Meanwhile, conventionally, pellet stoves have been operated using a fuel supply motor, screw, blower fan, exhaust fan, etc.

Patent applications have been filed for pellet stoves in the past. For example, Patent Document 1, listed below, discloses a pellet burner and pellet stove that is easy to attach to existing stoves and highly portable, and is equipped with a cylindrical fuel storage section that stores pellets and discharges them from an outlet, and a cylindrical combustion section that receives the pellets discharged from the outlet and burns them, with the fuel storage section removably attachable above the combustion section, and the combustion section being installable in the upper opening of the stove. When not in use, the combustion section can be stored in the fuel storage section.

The applicant has also disclosed a configuration for providing a stove system that can realize fireplace-like combustion, can use pellets as fuel, can effectively prevent soot from adhering to the glass window by preventing the backflow of combustion wind, and can fully enjoy the flickering flames inside, which includes a supply section that supplies firewood fuel and air, a main combustion chamber that communicates with the supply section and burns the firewood fuel, and an exhaust section from which the airflow from there is finally discharged. A main airflow induction chamber is provided between the main combustion chamber and the exhaust section to extend the airflow distribution path, and a front-flow side vent between the main combustion chamber and the main airflow induction chamber is provided at the top of the main airflow induction chamber and a rear-flow side vent between the main combustion chamber and the exhaust section is provided at the bottom. The main combustion chamber is also provided with a window through which the flames inside can be seen (Patent Document 2 listed below). This type of stove can automatically burn at a stable temperature and heat despite being unpowered and unelectrically charged, and has the following effects: it is convenient for heating, cooking, and presentation, has excellent maintenance properties, and is convenient for storage and transportation.

Patent No. 6756963 "Pellet burner and pellet stove" JP 2022-081723 A "Natural combustion stove, its usage method, and pellet box"

In recent years, in response to the growing demand for outdoor leisure and recreation activities such as camping, a variety of products have been developed and offered. One of these is the sauna. These include saunas that are used inside a tent using a portable stove as a heat source (tent saunas) and sauna rooms that are mounted on vehicles. However, there are still only a few stoves available that are suitable for such outdoor saunas, and there is a demand for stoves that have high combustion efficiency, particularly when using pellet fuel, and therefore low fuel consumption. There is also a demand for a method that allows for better control of the combustion state when using pellet fuel.

The problem that the present invention aims to solve is to provide a firewood/pellet stove that can improve the combustion efficiency when using pellet fuel, while taking into account the state of the prior art and based on the invention described in Patent Document 2 previously disclosed by the applicant. Also, to provide a firewood/pellet stove that can better control the combustion state when using pellet fuel, including improving the combustion efficiency.

Another object of the present invention is to provide a detachable pellet box that allows such pellets to be used in a dual-purpose firewood/pellet stove. A further object of the present invention is to provide a sauna that uses such a dual-purpose firewood/pellet stove, has good combustion efficiency, and is suitable for outdoor leisure activities.

The inventors of the present application have studied the above problems. As a result, based on the invention of the natural combustion stove and the pellet box used therein disclosed in the above Patent Document 2, they have discovered that combustion efficiency can be further improved by providing the pellet box with a secondary pellet amount adjustment means that secondarily adjusts the amount of pellets that fall naturally by the pellet amount adjustment means, and an air supply amount adjustment means that adjusts the amount of air supplied from the air supply port, and have completed the present invention based on this. In other words, the invention claimed in this application as a means for solving the above problems, or at least the invention disclosed therein, is as follows.

[1] A wood/pellet stove comprising: a supply section for supplying fuel for natural combustion and for supplying air; a main combustion chamber connected to the supply section where combustion takes place; an exhaust section through which the airflow from the main combustion chamber is finally exhausted; and a pellet box which is an attachment for storing and supplying pellet fuel that is detachable from the supply section, wherein the pellet box comprises a storage section for storing pellet fuel, a pellet amount adjustment means for adjusting the amount of pellet fuel supplied by natural fall from the storage section, and an air intake port, and further comprises a secondary pellet amount adjustment means for secondarily adjusting the amount of pellets that have naturally fallen below the pellet amount adjustment means, and an air intake amount adjustment means below the secondary pellet amount adjustment means for adjusting the amount of air supplied from the air intake port.
[2] The pellet box is formed so as to communicate with the main combustion chamber when attached to the supply section, and is equipped with a combustion section in which pellet fuel supplied by air supplied from the air intake port is combusted, characterized in that pellet fuel is burned, as described in [1].
[3] A firewood/pellet dual stove as described in either [1] or [2], characterized in that the pellet amount secondary adjustment means is formed by a lattice structure so that the intake air adjusted by the intake amount adjustment means flows to the combustion section.
[4] The wood/pellet dual stove described in [3], wherein the pellet amount secondary adjustment means is formed to be swingable, and the opening area to the combustion section is adjusted by the swinging.

[5] The firewood/pellet dual-use stove described in [4], wherein the air supply volume adjustment means is formed to be swingable, and the volume of air supply is adjusted by the swinging.
[6] A wood/pellet dual-use stove as described in any of [1], [2], [4], or [5], characterized in that a main airflow guide chamber is provided between the main combustion chamber and the exhaust section to extend the internal airflow path, the main airflow guide chamber has a front-flow side vent between the main combustion chamber at the top and the main airflow guide chamber, and a rear-flow side vent between the main combustion chamber and the exhaust section at the bottom, and the main combustion chamber has a window through which the internal flame can be seen.
[7] The wood/pellet dual-use stove described in [6], characterized in that the main airflow induction chamber is provided back-to-back with the rear of the main combustion chamber, and the exhaust section is provided in contact with the main airflow induction chamber as well as in contact with the main combustion chamber and the supply section.

[8] A pellet box for storing and supplying pellet fuel, which can be attached to and detached from the supply section of a firewood/pellet stove, the pellet box having a supply section for supplying fuel for natural combustion and air, a main combustion chamber connected to the supply section and in which combustion takes place, and an exhaust section through which airflow from the main combustion chamber is finally discharged, the pellet box being characterized in that it comprises a storage section for storing pellet fuel, a pellet amount adjustment means for adjusting the amount of pellet fuel supplied by natural fall from the storage section, and an air intake port, and further comprising a secondary pellet amount adjustment means for secondarily adjusting the amount of pellets that have naturally fallen below the pellet amount adjustment means, and an air intake amount adjustment means below the secondary pellet amount adjustment means for adjusting the amount of air supplied from the air intake port.
[9] The pellet box according to [8], characterized in that it is provided with a combustion section which is formed to communicate with the main combustion chamber when attached to the supply section and in which the pellet fuel supplied by the air supply from the air inlet is combusted, thereby combusting the pellet fuel.
[10] The pellet box according to either [8] or [9], characterized in that the pellet amount secondary adjustment means is formed by a lattice structure so that the intake air adjusted by the intake amount adjustment means flows to the combustion section.

[11] The pellet box according to [10], wherein the pellet amount secondary adjustment means is formed to be swingable, and the opening area to the combustion section is adjusted by the swinging.
[12] The pellet box according to [11], wherein the air supply amount adjusting means is formed to be swingable, and the amount of air supply is adjusted by the swinging.
[13] A wood/pellet dual-use stove as described in any one of [1], [2], [4], [5], or [7], characterized in that it is used as a heat source for a sauna room.
[14] A sauna room structure comprising a wood/pellet dual stove described in any one of [1], [2], [4], [5], or [7], and a sauna room space using the wood/pellet dual stove as a heat source.
[15] The sauna room structure described in [14], characterized in that it can be loaded or installed on a moving means, or is loaded or installed on a moving means.

The firewood/pellet stove, pellet box, and sauna room structure of the present invention are configured as described above, and therefore are able to solve the above-mentioned problems and achieve the respective effects. In other words, based on the invention described in the above-mentioned document 2, which was previously disclosed by the applicant, it is possible to further improve the combustion efficiency when using pellet fuel in a firewood/pellet stove. It is also possible to provide a firewood/pellet stove that allows for better control of the combustion state when using pellet fuel, including improving the combustion efficiency.

It is also possible to provide a pellet box that can be attached and detached from such a wood/pellet stove. Furthermore, by using the wood/pellet stove of the present invention, a sauna with good combustion efficiency and suitable for outdoor leisure activities can be realized.
The definition of combustion efficiency is "energy obtained by combustion / energy contained in the fuel." In the present invention described below, the main point is "energy released into the room (or energy used to heat the sauna stones) / energy contained in the fuel," which is actually "thermal efficiency." However, in this application, we will use the term "combustion efficiency" to explain.

FIG. 1 is an explanatory diagram conceptually showing the basic structure of the wood/pellet dual-use stove of the present invention (with the pellet box removed). FIG. 1 is an explanatory diagram conceptually showing the basic structure of the firewood/pellet dual-use stove of the present invention (with pellet box attached). FIG. 1 is an explanatory diagram conceptually showing the basic configuration of a pellet box according to the present invention. FIG. 4 is an explanatory diagram conceptually showing the operation of the pellet box configuration example of the present invention shown in FIG. 3. FIG. 2 is a side view of an embodiment of a pellet box according to the present invention. FIG. 6 is a perspective view of the embodiment shown in FIG. 5 . 7 is a cross-sectional view taken along the line CC' in FIG. 6 (illustration of some exterior components is omitted). This is an oblique view showing the main body part (with the pellet box removed) of a firewood/pellet dual-use stove embodiment corresponding to the pellet box embodiment shown in Figure 5 etc., from the back side where the exhaust part is located. FIG. 9 is a perspective view showing a state in which a pellet box is attached to the embodiment shown in FIG. 8 . FIG. 10 is a view of the state of FIG. 9 as viewed from the front surface (the side opposite to the surface on which the exhaust portion is provided). 1 is an explanatory diagram conceptually showing the basic structure of the sauna room structure of the present invention. FIG. 1 is an explanatory diagram conceptually showing an example of the form in which the sauna room structure of the present invention is provided. This is a photograph of the interior of an embodiment of a movable sauna room structure. 1 is a perspective photograph of the wood/pellet dual-use stove of the present invention used in the experiment. FIG. 2 is a cross-sectional view of a main part of a pellet box showing the experimental conditions of this experiment. 1 is a graph showing exhaust gas temperature, _O2 concentration, and generated CO concentration as results of a combustion experiment under each experimental condition. 1 is a graph showing exhaust gas temperature, _O2 concentration, and generated CO concentration in a combustion experiment using a stove according to a conventional method not equipped with the adjustment method of the present invention, i.e., the technology disclosed in Patent Document 2. This is a graph showing the sauna stone temperature and the temperature inside the main combustion chamber as results of combustion experiments under each experimental condition.

The present invention will now be described in detail with reference to the drawings.
1 and 2 are explanatory diagrams conceptually showing the basic structure of the firewood/pellet dual stove of the present invention, the former showing the state with the pellet box removed, and the latter showing the state with the pellet box attached. As shown in these figures, the firewood/pellet dual stove 100 is equipped with a supply section 20 that supplies fuel for natural combustion and supplies air, a main combustion chamber 30 that communicates with the supply section 20 and where combustion takes place, an exhaust section 40 where the airflow from the main combustion chamber 30 is finally exhausted, and a pellet box 10 that is an attachment for storing and supplying pellet fuel and is detachable from the supply section 20. The pellet box 10 is mainly configured to have a storage section for storing pellet fuel, a pellet amount adjustment means for adjusting the amount of pellet fuel supplied by natural fall from the storage section, and an air supply port, and further includes a pellet amount secondary adjustment means for secondarily adjusting the amount of pellets that have naturally fallen below the pellet amount adjustment means, and an air supply amount adjustment means below the pellet amount secondary adjustment means for adjusting the amount of air supplied from the air supply port.

When the firewood/pellet dual stove 100 having such a configuration is used as a firewood stove, the fuel for natural combustion, i.e. firewood, is supplied from the supply unit 20 and air for combustion is supplied, and the firewood supplied from the supply unit 20 is burned in the main combustion chamber 30 by this air supply, and the stove functions as a heating and heat source. The airflow from the main combustion chamber 30 is finally exhausted from the exhaust unit 40. The pellet box 10 of the present invention can be attached and detached to the supply unit 20 for supplying air and firewood, and the firewood/pellet dual stove 100 can also be used as a pellet stove. In other words, the firewood/pellet dual stove 100 can be used both ways: using fuel for natural combustion/firewood as fuel, and using pellets as fuel.

When using the wood/pellet stove 100 as a pellet stove, the pellet box 10 is attached to the supply section 20 as shown in FIG. 2. Pellet fuel (hereinafter simply referred to as "pellets") is stored inside the pellet box 10 and supplied for combustion. As a result, pellets are supplied from the supply section 20 and air for combustion is supplied, and the pellets supplied from the pellet box 10 are burned inside the wood/pellet stove 100 by this air supply, and the stove functions as a heating and heat source. The airflow from the main combustion chamber 30 is finally exhausted from the exhaust section 40.

The pellet box itself, which is one element constituting the wood/pellet dual stove of the present invention, is also within the scope of the present invention. The pellet box will now be described.
Fig. 3 is an explanatory diagram conceptually showing an example of the configuration of the pellet box of the present invention. The reference numeral "10" is used to indicate the pellet box in this diagram, which is the same as the reference numeral "10" used to indicate the pellet box in the conceptual explanatory diagrams of Figs. 1 and 2. As shown in the diagram, the pellet box 10 of the present invention is mainly composed of a storage section 2 for storing pellet fuel, a pellet amount adjusting means 3 for adjusting the supply amount of pellets by natural drop from the storage section 2, and an air supply port 4, and further includes a pellet amount secondary adjusting means 6 for secondarily adjusting the amount of pellets naturally dropped below the pellet amount adjusting means 3, and an air supply amount adjusting means 8 for adjusting the amount of air supplied from the air supply port 4 below the pellet amount secondary adjusting means 6.

In this pellet box 10, with this configuration, pellets are stored in the storage section 2 and supplied for combustion. During supply, the pellet quantity adjustment means 3 adjusts the supply amount of pellet fuel that falls naturally from the storage section 2. Air for combustion is also supplied from the air inlet 4. The pellets are burned by the pellets supplied in an amount adjusted by the pellet quantity adjustment means 3 and the air supplied from the air inlet 4. In the pellet box 10 of the present invention, the conditions of this combustion can be further adjusted. That is, the amount of pellets that fall naturally below the pellet quantity adjustment means 3 can be secondarily adjusted by the pellet quantity secondary adjustment means 6, and the amount of air supplied from the air inlet 4 can be adjusted by the air supply amount adjustment means 8.

Figure 4 is an explanatory diagram conceptually showing the operation of the pellet box configuration example of the present invention shown in Figure 3. As shown in Figure 2 above, the pellet box 10 is formed to communicate with the main combustion chamber 30 when attached to the supply unit 20, but at the same time, as shown in Figure 4, the pellet box 10 can be configured to include a combustion unit 5 in which the pellets supplied by the air supplied from the air inlet 4 are burned. In other words, the pellets are burned within the pellet box 10.

With this configuration, in this pellet box 10, the combustion BR of the pellets PL supplied from the storage section 2 is carried out in the combustion section 5, which communicates with the main combustion chamber 30, by the supply air AR from the air inlet 4. Here, the supply amount of the pellets PL supplied from the storage section 2 can be adjusted by the pellet amount adjustment means 3 and the secondary pellet amount adjustment means 6, and the supply air AR can be adjusted by the supply air amount adjustment means 8. Examples of these adjustment methods will be described below.

As shown in Figures 4 and 3, the pellet amount secondary adjustment means 6 of the pellet box 10 of this firewood/pellet dual stove is formed in a plate-like shape that can be swung (SW) to block/open the cross section of the supply path for the pellets PL that fall naturally from the storage section 2, and the adjustment method can be one in which the opening area to the combustion section 5 is adjusted by the swing SW. The swing SW for blocking/opening the pellet amount secondary adjustment means 6 can be made continuous. However, other structures, such as a stepped structure, are also acceptable.

In the pellet box 10 according to the present invention having such a configuration, the opening area to the combustion section 5, i.e., the cross-sectional area of the pellet PL supply path to the combustion section 5, is adjusted by the swing SW of the swingable pellet amount secondary adjustment means 6, which is installed so as to be able to block and open the cross section of the supply path of the pellets PL that naturally fall from the storage section 2 while being adjusted in natural fall amount by the pellet amount adjustment means 3, thereby adjusting the final pellet PL supply amount and the combustion BR of the pellets PL in the combustion section 5. The angle range, shape, size, etc. of the swing SW of the pellet amount secondary adjustment means 6 can be designed arbitrarily. In addition, the swing SW can be structured so as to be operable from outside the pellet box 10.

As shown in Figures 4 and 3, the air intake adjustment means 8 of the pellet box 10 of this firewood/pellet stove is formed on the air intake AR flow path leading to the combustion section 5 so that it can swing to adjust the cross-sectional area of the flow path so that the amount of air intake AR from the air intake port 4 can be adjusted, and the swing SW can be used to adjust the opening area to the combustion section 5 and adjust the amount of air intake. The swing SW for adjusting the intake amount of the air intake adjustment means 8 can be a continuous structure. However, other structures such as a stepped structure are also possible.

In the pellet box 10 of the present invention having such a configuration, the air supply AR from the air supply port 4 is adjusted by the swing SW of the swingable air supply amount adjustment means 8 installed on the flow path leading to the combustion section 5 so that the size of its cross-sectional area can be adjusted, thereby adjusting the opening area to the combustion section 5, i.e., the cross-sectional area of the air supply AR to the combustion section 5, and thus the final amount of air supply can be adjusted, and the combustion BR of the pellets PL in the combustion section 5 can be adjusted. The angle range, shape, size, etc. of the swing SW of the air supply amount adjustment means 8 can be designed as desired. In addition, the swing SW can be structured so that it can be operated from outside the pellet box 10.

As shown in the figure, the pellet amount adjustment means 3 is in the form of a plate that receives the pellets PL in the storage section 2 from below, and can be configured to adjust the amount of pellets PL that naturally fall from the storage section 2 by blocking and opening with a sliding movement SL. The sliding movement SL for blocking and opening the pellet amount adjustment means 3 can be continuous. However, other structures, such as a stepped structure, are also possible.

In the pellet box 10 of the present invention having such a configuration, the pellet amount adjustment means 3 forms the bottom of the storage section 2, and the sliding SL adjusts the advancement and retreat of the pellet amount adjustment means 3, which is the bottom, to adjust the width of the opening at the bottom, and the amount of pellets PL that fall naturally from the storage section 2 is adjusted depending on the width of the opening. The sliding SL can be structured so that it can be operated from outside the pellet box 10.

FIG. 5 is a side view of an embodiment of a pellet box according to the present invention.
Fig. 6 is a perspective view of the embodiment shown in Fig. 5, and Fig. 7 is a cross-sectional view taken along the line CC' in Fig. 6 (illustration of some exterior components is omitted). As shown in Figs. 7 and 6,
The pellet amount secondary adjustment means 56 of this pellet box 510 is characterized in that it is formed with a lattice structure so that the intake air adjusted by the intake amount adjustment means 58 flows to the combustion section 55.

In the pellet box 510 of this embodiment, the pellet amount secondary adjustment means 56, which is made of a lattice structure with gaps, allows the supply air adjusted by the intake amount adjustment means 58 to flow smoothly to the combustion section 55. As shown in the conceptual explanatory diagrams of Figures 3 and 4 above, both the pellet amount secondary adjustment means 56 and the intake amount adjustment means 58 can be structured to freely adjust the degree of opening and closing by swinging, and the flow path of the supply air by the intake amount adjustment means 58 may be blocked by the pellet amount secondary adjustment means 56. However, even in such a case, since the pellet amount secondary adjustment means 56 has a lattice structure, the intake air to the combustion section 55 is not blocked, and the final supply air amount adjustment is made by the degree of opening and closing of the intake amount adjustment means 58.

As shown in FIG. 5, the secondary pellet amount adjustment means 56 can be swung by an operating part 56m, the intake amount adjustment means 58 can be swung by an operating part 58m, and the pellet amount adjustment means 53 can be slid by an operating part 53m, all from outside the pellet box 510. The storage section 52 also has a storage section slit 52s for checking the remaining amount of pellets stored inside, the combustion section 55 has a combustion section door 55d for performing maintenance, and an ash receiver 57 is provided below the combustion section 55.

Figure 8 is a perspective view showing the main body (with the pellet box removed) of a firewood/pellet dual stove embodiment corresponding to the pellet box embodiment shown in Figure 5 etc., from the rear side where the exhaust section is located. As shown in the figure, when the pellet box, which is a component of this firewood/pellet dual stove 5100, is removed, the supply section 520 is exposed, and natural combustion fuel, i.e. firewood, can be supplied from the supply section door 520d into the main combustion chamber 530 and burned, allowing it to be used as a natural combustion stove as a heating/heat source.

Figure 9 is a perspective view showing the embodiment shown in Figure 8 with a pellet box attached. Also, Figure 10 is a view of the state shown in Figure 9 from the front side (the side opposite the exhaust section). As shown in these figures, the firewood/pellet dual-use stove 5100 can be turned into a pellet stove that burns pellet fuel by attaching the pellet box 510 to the supply section 520, and can be used as a heating/heat source. The effects of increasing combustion efficiency and adding control over the combustion state when used as a pellet stove are as described above.

Although not specifically shown, a main airflow induction chamber is provided between the main combustion chamber 530 and the exhaust section 540 to extend the internal airflow path, similar to the technology disclosed in Patent Document 2, and this main airflow induction chamber has a front-flow side vent between the main combustion chamber 530 at the top and a rear-flow side vent between the main combustion chamber 530 and the exhaust section 540 at the bottom. The main combustion chamber 530 can be configured with a window through which the internal flame can be seen, i.e., a main combustion chamber window 530w, and the same effects as the disclosed technology can be obtained.

Although this is not shown, similar to the technology disclosed in Patent Document 2, the main body airflow induction chamber can be provided back-to-back with the rear surface of the main body combustion chamber 530, and the exhaust section 540 can be provided in contact with the main body airflow induction chamber as well as in contact with the main body combustion chamber 530 and the supply section 520, thereby obtaining the same effects as those of the disclosed technology.

In addition, a firewood/pellet dual-use stove having at least one of the following configurations <Op1> to <Op3> is also within the scope of the present invention.
<Op1> An oven installed below the main combustion chamber. <Op2> An upper lid installed on the upper surface of the main combustion chamber. <Op3> Legs using the four-leg stable installation structure or four-leg horizontal installation structure described in Japanese Patent No. 3594299.

Figure 11 is an explanatory diagram conceptually showing the basic configuration of the sauna room structure of the present invention. As shown in the figure, the firewood/pellet dual stove 6100 of the present invention having any of the configurations described above can be installed in the sauna room space 6200 and used as a heat source for the sauna room. In this way, the sauna room structure 6300 consisting of the firewood/pellet dual stove 6100 and the sauna room space 6200 that uses it as a heat source is also within the scope of the present invention.

Figure 12 is an explanatory diagram conceptually showing an example of the form in which the sauna room structure of the present invention is provided. As shown in the figure, the sauna room structure 7300 can be loaded or installed on a mobile means 7900, or can be in a form in which it is loaded or installed. With this configuration, the sauna room structure 7300 can be used anywhere the mobile means 7900 can move, making it convenient for outdoor use such as camping.

Figure 13 is a photograph of the interior of an embodiment of a portable sauna room structure. As shown in the figure, this sauna room structure 8300 is installed on a means of transportation (vehicle), and is configured with a firewood/pellet stove 8100 installed as a heat source in a sauna room space 8200. In this example, you can enjoy a sauna while being able to see the combustion and flames inside the main combustion chamber 830 through the main combustion chamber window 830w of the firewood/pellet stove 8100.

<Experiment>
An experiment was conducted to confirm the effect of improving the combustion efficiency of the firewood/pellet dual-use stove of the present invention.
Fig. 14 is a perspective photograph of the wood/pellet stove of the present invention used in the experiment. As shown in the figure, the wood/pellet stove 9100 is configured to include a supply section 920 that supplies fuel for natural combustion and supplies air, a main combustion chamber 930 that communicates with the supply section 920 and performs combustion, an exhaust section (not shown) that finally exhausts the airflow from the main combustion chamber 930, and an attachment pellet box 910 that is detachable from the supply section 920 and stores and supplies pellet fuel. The pellet box 910 is configured as already described, that is, includes a storage section, a pellet amount adjustment means, an air intake port, a pellet amount secondary adjustment means, an air supply amount adjustment means, and a combustion section.

Figure 15 shows the experimental conditions of this experiment using a cross-sectional view of the main parts of the pellet box. The purpose of this experiment was to confirm the effect of controlling the combustion state and improving the combustion efficiency by adjusting the pellet supply amount and the air supply amount. The pellet supply amount was set under two conditions, with the pellet amount adjustment means 93 fully open and the opening degree of the pellet amount secondary adjustment means 96 at the minimum and maximum, and the air supply amount was set under two conditions, with the opening degree of the air supply amount adjustment means 98 at the minimum and maximum. Combustion was performed under four conditions by combining these, and the specified parameters were measured. The four experimental conditions are as follows. In the following, the opening degree for the air supply amount is also referred to as the "air port opening degree".

Experimental condition 1 ((a) in the figure)
Pellet supply amount: minimum, Air port opening: minimum, Experimental condition 2 ((b) in the figure)
Pellet supply amount: minimum, air port opening: maximum, experimental condition 3 ((c) in the figure)
Pellet supply amount: maximum, air port opening: minimum, experimental condition 4 ((d) in the figure)
Pellet supply amount: maximum, Air port opening: maximum. Each of the experimental conditions 1 to 4 was performed using one firewood/pellet dual-purpose stove 9100, with the combustion conditions switched in the order of these conditions.

The measured parameters are as follows:
- Temperature of exhaust gas from combustion (℃)
- _O2 concentration in exhaust gas (%)
- CO concentration in exhaust gas (ppm)
・Sauna stone temperature (℃)
・Main combustion chamber (combustion chamber) temperature (℃)
This experiment was conducted using a wood/pellet stove 9100 as the heat source for the sauna room. "Sauna stone temperature" is the temperature of the sauna stones heated by the stove 9100.

FIG. 16 is a graph showing the exhaust gas temperature, _O2 concentration, and generated CO concentration as the results of the combustion experiment under each experimental condition. In the figure, the horizontal axis indicates the elapsed time, the left vertical axis indicates the exhaust gas temperature (℃) and _O2 concentration (%) in the exhaust gas, and the right vertical axis indicates the CO concentration (ppm). The figure shows the results of testing experimental conditions 1, 2, 3, and 4 in order between 11:30 and 14:00 on the day of the experiment. As shown in the figure, the firewood/pellet dual-use stove 9100 was preheated with firewood before the start of the experiment, and the combustion section door ("window" in the figure) was opened and taken out immediately before the start of the experiment. In addition, ash was removed at the start of the experiment under experimental condition 3, and the combustion door was opened once during the experiment to remove soot from the glass surface.

Fig. 17 is a graph showing the exhaust gas temperature, _O2 concentration, and generated CO concentration in a combustion experiment using a conventional stove not equipped with the adjustment method of the present invention, i.e., a stove according to the technology disclosed in Patent Document 2. In the figure, the horizontal axis shows the passage of time, the left vertical axis shows the exhaust gas temperature (°C) and _O2 concentration (%) in the exhaust gas, and the right vertical axis shows the CO concentration (ppm). The horizontal axis corresponds to Fig. 16, and shows the results of testing the conventional stove between 14:30 and 15:30 on the day of the experiment.

Figure 18 is a graph showing the sauna stone temperature and the temperature inside the main combustion chamber as the results of the combustion experiment under each experimental condition. The horizontal axis shows the passage of time, and the vertical axis shows the temperature (°C). As with Figure 16, the results are shown for experimental conditions 1, 2, 3, and 4, tested in that order between 11:30 and just after 14:00 on the day the experiment was conducted.

Tables 1 to 5 show the 5-minute averages, maximum values, and minimum values of the measured parameters under each of the experimental conditions 1 to 4. In each table, "Experimental condition 1" is shown as "Condition 1", etc. Also, in Table 5, "Conventional model" refers to a conventional stove. In the tables, "air ratio" refers to the ratio of the amount of air actually used to the theoretical amount of air. The theoretical amount of air is the amount of air required for complete combustion of fuel. In reality, it is impossible to mix fuel and air evenly, so even if only the theoretical amount of air is supplied, there is a tendency for air to be insufficient. Therefore, a slightly larger amount of air is supplied.

From the results shown in the graphs and tables, the following was confirmed and considered:
1) Under experimental condition 1, in which both the pellet supply amount and the air amount were adjusted to a minimum, the temperature inside the combustion chamber rose to nearly 400°C. On the other hand, under experimental condition 2, the opening of the air port was changed to the maximum, and as a result, the temperature inside the combustion chamber and the exhaust gas temperature decreased. From this, it is believed that the increased amount of air under experimental condition 2 flowed into the combustion chamber without being used for combustion, resulting in a decrease in the temperature inside the combustion chamber.

Therefore, when using the wood/pellet dual-use stove 9100 of the present invention and keeping the minimum pellet supply amount as a common condition, it was shown that a combustion control method can be adopted in which the amount of air supply is reduced when it is desired to increase combustion efficiency, and conversely, when it is desired to suppress combustion efficiency and thereby the temperature inside the combustion chamber, the amount of air supply is increased as in experimental condition 2.

2) In experimental condition 1, where both the amount of pellets supplied and the amount of air were adjusted to a minimum, combustion could continue for approximately two hours without the need for additional pellet supply. In addition, the temperature of the sauna stones rose to nearly 90°C, confirming that it was possible to burn with low fuel consumption by limiting the amount of pellets supplied while still functioning as a heat source and sauna stove. In this experiment, the temperature sensor was placed relatively close to the surface of the sauna stones, so it can be assumed that the temperature in the center was higher, and it is believed that condition 1 provided sufficient functionality as a sauna stove.

Therefore, it has been shown that by using the firewood/pellet dual-purpose stove 9100 of the present invention and restricting the amount of pellets supplied and the amount of air supplied, it is possible to achieve desirable combustion in terms of both improved combustion efficiency and reduced fuel consumption.

3) Under experimental condition 3, in which the pellet supply amount was maximized, the temperature inside the combustion chamber exceeded 600°C. In addition, under these conditions, in which the amount of air supplied was restricted, the CO concentration decreased, reaching a 5-minute average value of 181.2 ppm, indicating favorable combustion conditions.

Therefore, when using the wood/pellet dual-use stove 9100 of the present invention, it was shown that in order to control the combustion state to a favorable state in which the CO concentration produced is minimized, it is appropriate to adjust the amount of pellets supplied to a large amount and the amount of air supplied to a small amount, as in this condition.

4) Even under experimental condition 4, in which the pellet supply amount was at its maximum, the temperature inside the combustion chamber exceeded 600°C. On the other hand, under these conditions, a drop in the exhaust gas temperature was observed. From this, it is believed that, similar to experimental condition 2 described above, a portion of the supplied air flows into the combustion chamber without being used for combustion, resulting in a phenomenon that causes a drop in the temperature inside the combustion chamber.

Therefore, when using the wood/pellet dual-use stove 9100 of the present invention, and increasing the amount of pellets supplied to achieve high combustion efficiency, if you wish to reduce this and suppress the temperature inside the combustion chamber, it has been shown that a combustion control method can be adopted in which the amount of air supplied is increased, as in condition 4.

5) Regarding exhaust gas temperature, the measurement locations (distance from the combustion chamber) are different between experimental conditions 1 to 4 and the conventional method, so a simple comparison cannot be made; however, it is presumed that the combustion conditions under the conventional method are close to those under experimental conditions 1 and 2 of the present invention. Based on this presumption, it can be said that the CO concentration can be kept lower under experimental conditions 1 and 2 of the present invention as well, compared to the conventional method, and the combustion conditions have been improved. The same is true for experimental condition 3 of the present invention. Furthermore, as mentioned above, under experimental condition 3 of the present invention, the CO concentration is significantly improved compared to the conventional method.

6) In addition, the _O2 concentration in the exhaust gas is also lower than that of the conventional method under the experimental conditions 1 and 2 of the present invention. Therefore, it is considered that the supplied air is efficiently used for combustion under the experimental conditions 1 and 2 of the present invention.

The results of the above experiments confirmed that the adjustment method of the present invention makes it possible to improve combustion efficiency and control the combustion state in various ways.

The wood/pellet stove, pellet box, and sauna room structure of the present invention, based on the invention described in the above-mentioned document 2 previously disclosed by the applicant, can provide a wood/pellet stove with higher combustion efficiency, and can be used to provide a sauna for outdoor leisure activities with high combustion efficiency. Therefore, this invention has high industrial applicability in all fields of use, manufacturing, and all related fields of wood/pellet stoves, including outdoor recreational uses such as camping.

2, 52, 92...Storage section 3, 53, 93...Pellet amount adjustment means 4, 54, 94...Air intake port 5, 55, 95...Combustion section 6, 56, 96...Pellet amount secondary adjustment means 8, 58, 98...Air intake amount adjustment means 10, 510, 610, 710, 910...Pellet box 20, 520, 620, 720, 920...Supply section 30, 530, 630, 730, 830, 930...Main combustion chamber 40, 540, 640, 740, 840...Exhaust section 100, 5100, 6100, 7100, 8100, 9100...Firewood/pellets Dual-purpose stove 52s...storage section slits 53m, 93m...operation portion 55d of pellet amount adjustment means...combustion section door 56m...operation portion 57, 97 of secondary pellet amount adjustment means...ash receiver 58m...operation portion 520d, 920d of intake amount adjustment means...supply section door 530w, 830w, 930w...main combustion chamber window 6200, 7200, 8200...sauna room space 6300, 7300, 8300...sauna room structure 7900...moving means 99...ash removal means AR...air supply BR...combustion PL...pellet fuel SL...sliding SW...swing

Claims (15)

A supply unit that supplies fuel for spontaneous combustion and supplies air;
a main combustion chamber communicating with the supply section and in which combustion takes place;
The apparatus includes an exhaust section through which the airflow from the main combustion chamber is finally exhausted, and a pellet box which is an attachment for storing and supplying pellet fuel and is detachable from the supply section,
The pellet box is
a storage section for storing pellet fuel;
The fuel cell further includes a pellet amount adjusting means for adjusting the amount of pellet fuel supplied by natural fall from the storage portion, and an air inlet.
a pellet amount secondary adjusting means for secondarily adjusting the amount of pellets naturally falling below the pellet amount adjusting means;
This firewood/pellet dual-use stove is characterized in that an air intake amount adjustment means for adjusting the amount of air intake from the air intake port is provided below the pellet amount secondary adjustment means. The wood/pellet dual-use stove described in claim 1 is characterized in that the pellet box is formed to communicate with the main combustion chamber when attached to the supply section, and is equipped with a combustion section in which pellet fuel supplied by air supplied from the air inlet is burned, thereby burning pellet fuel. A firewood/pellet dual-use stove as described in claim 1 or 2, characterized in that the pellet amount secondary adjustment means is formed with a lattice structure so that the intake air adjusted by the intake amount adjustment means flows to the combustion section. The wood/pellet dual-use stove of claim 3, characterized in that the secondary pellet amount adjustment means is swingable, and the opening area to the combustion section is adjusted by the swinging motion. The firewood/pellet dual-use stove of claim 4, characterized in that the air supply volume adjustment means is swingable, and the volume of air supply is adjusted by the swinging motion. A main airflow guide chamber is provided between the main combustion chamber and the exhaust section to extend the internal airflow path,
The main airflow induction chamber has a front-flow side vent between the main combustion chamber and the upper part.
A downstream side vent is provided between the lower portion and the exhaust portion,
6. A wood/pellet stove as claimed in claim 1, 2, 4 or 5, characterized in that the main combustion chamber is provided with a window through which the internal flame can be seen. The wood/pellet dual-use stove of claim 6, characterized in that the main body airflow induction chamber is provided back-to-back with the rear surface of the main body combustion chamber, and the exhaust section is provided in contact with the main body airflow induction chamber as well as in contact with the main body combustion chamber and the supply section. A pellet box for storing and supplying pellet fuel, which is detachable from the supply section of a firewood/pellet stove, is provided, the pellet box being attached to and detachable from the supply section of the firewood/pellet stove, the pellet box comprising: a supply section for supplying fuel for natural combustion and supplying air; a main combustion chamber communicating with the supply section in which combustion takes place; and an exhaust section through which the airflow from the main combustion chamber is finally exhausted;
a storage section for storing pellet fuel;
The fuel cell further includes a pellet amount adjusting means for adjusting the amount of pellet fuel supplied by natural fall from the storage portion, and an air inlet.
a pellet amount secondary adjusting means for secondarily adjusting the amount of pellets naturally falling below the pellet amount adjusting means;
A pellet box characterized in that an air supply amount adjusting means for adjusting the amount of air supplied from the air supply port is provided below the pellet amount secondary adjusting means. The pellet box according to claim 8, characterized in that it is formed to communicate with the main combustion chamber when attached to the supply section, and is provided with a combustion section in which the pellet fuel supplied by the air supply from the air supply port is combusted, and the pellet fuel is combusted. The pellet box according to claim 8 or 9, characterized in that the pellet amount secondary adjustment means is formed with a lattice structure so that the intake air adjusted by the intake amount adjustment means flows to the combustion section. The pellet box according to claim 10, characterized in that the pellet amount secondary adjustment means is swingable, and the opening area to the combustion section is adjusted by the swinging. The pellet box according to claim 11, characterized in that the air supply amount adjustment means is formed to be swingable, and the amount of air supply is adjusted by the swinging. A wood/pellet dual-use stove as described in any one of claims 1, 2, 4, 5, and 7, characterized in that it is used as a heat source for a sauna room. A sauna room structure comprising a firewood/pellet stove as described in any one of claims 1, 2, 4, 5, and 7, and a sauna room space using the firewood/pellet stove as a heat source. The sauna room structure according to claim 14, characterized in that it can be loaded or installed on a moving means, or is loaded or installed on a moving means.