Flame viewing device

Abstract

[Problem] To provide a flame viewing device which is compact so as to allow for a wider range of choice in installation location, and which can prevent fires. [Solution] Provided is a flame viewing device having an enclosure 10 with transparent portions 17, 18 and a burner 40 that releases a gas into an interior space S1 of the enclosure 10, thus allowing a flame produced by burning the gas to be viewed through the transparent portions 17, 18, wherein the gas is supplied from a removable cassette gas cylinder CB, a thermal barrier 73 is laid out above the burner 40 in the interior space S1 to prevent convective heat from the flame from heading to a top panel 15 of the enclosure 10, and at least one of the four sides of the enclosure 10 around the thermal barrier 73 has a heat dissipation port 75 for releasing convective heat into an external space.

Description

Flame viewing device

[0001] The present invention relates to a flame viewing device that uses a cassette gas cylinder.

[0002] It has long been known that the flickering flames produced by burning firewood in a fireplace have psychological effects, such as a sense of relaxation, on viewers. However, fireplaces that use firewood are expensive and difficult to maintain. Therefore, there are flame viewing devices that use fuels other than firewood, such as gas (see, for example, Patent Documents 1 and 2).

[0003] The flame viewing device of Patent Document 1 has a burner that ejects gas, and the gas from the burner is combusted in a sealed casing to generate a flame that can be viewed. The device of Patent Document 1 exhausts the combustion gas outdoors through an exhaust duct to prevent heat damage to walls around the installation location. It also has an air intake duct that supplies outdoor air into the casing to prevent incomplete combustion of the flame. The device of Patent Document 2 is also a fireplace-type heater that allows viewing of the flame generated by burning gas, and similarly, the combustion exhaust is forcibly exhausted outdoors through an exhaust duct by an exhaust fan.

[0004] However, the devices in Patent Documents 1 and 2 are configured to connect to the outdoors via exhaust ducts and air intake ducts, which limits installation locations and necessitates a certain degree of size. Therefore, the applicant considered a small, portable device without exhaust ducts or air intake ducts. However, without an exhaust duct connecting to the outdoors, the device's top plate could overheat and fall on or touch an object, potentially causing a fire. Being portable in particular increases the risk of fire, as the device can be used in a variety of environments different from those of a regular fireplace.

[0005] Patent No. 5394880 Patent No. 4554506

[0006] An object of the present invention is to provide a flame viewing device that is small, can be installed in a wider range of locations, and can prevent fires.

[0007] According to the present invention, the above problem is solved by a flame viewing device which has a housing with a transparent part and a burner which releases gas into the internal space of the housing, and allows the flame produced by burning the gas to be viewed through the transparent part, wherein the gas is supplied from a detachable cassette gas cylinder, and above the burner in the internal space a heat insulating wall is arranged to prevent convection heat from the flame from being directed towards the top plate of the housing, and at least one of the four side surfaces of the housing has a heat release port around the heat insulating wall for releasing the convection heat to the external space.

[0008] With the above-described configuration, the flames generated by gas combustion inside can be viewed through the transparent portion of the housing. Furthermore, since gas is supplied using a portable cassette gas cylinder, the device can be made compact and easily moved, broadening the range of installation locations. A heat shield is provided above the burner in the interior space to prevent convection heat from the flames from reaching the top plate of the housing, preventing the top plate from overheating due to convection heat. Furthermore, at least one of the four side surfaces of the housing has a heat radiator around the heat shield for discharging convection heat to the outside space. Therefore, convection heat that strikes the heat shield can be effectively discharged through the heat radiator, preventing overheating of the top plate.

[0009] Preferably, an object to be heated is provided on the top plate side using heat at a temperature higher than the heat radiation temperature from the heat radiation port. Therefore, the heat can be recovered by the object to be heated, thereby lowering the temperatures of the heat radiation port and the top plate.

[0010] Preferably, the heated object is an incense burner, the top plate has a top plate hole that penetrates the thickness direction, and the incense burner is inserted into the top plate hole. This allows a large amount of heat to be concentrated and consumed in the incense burner, which typically requires a temperature of around 150°C or higher, thereby effectively lowering the temperature of the top plate and the heat dissipation port. Furthermore, because the incense burner is inserted into the top plate hole that penetrates the thickness direction of the top plate, it effectively prevents falling objects from coming into contact with the incense burner and facilitates the transfer of heat to the incense burner before it reaches the top plate. Furthermore, since the effect of burning incense is relaxing, the relaxing effect of watching the flickering flame can be further enhanced. In particular, since the user is close to the device while watching the flame, the fragrance can be effectively inhaled without being conscious of it.

[0011] Preferably, the heat insulating wall separates the flame-side space from the top-plate space without forming any through-holes in the area of ​​the internal space exposed to the flame side, and the bottom surface of the incense burner is in contact with the upper surface of the area of ​​the heat insulating wall exposed to the flame side of the internal space. Therefore, the hole-less heat insulating wall can guide almost all of the convection heat to the heat dissipation port. Furthermore, since the heat from the heated heat insulating wall is conducted to the bottom surface of the incense burner that it contacts and consumed, overheating of the top plate due to heat conduction can be effectively prevented.

[0012] Preferably, the heat-shielding wall has a heat-shielding wall hole that penetrates the wall thickness, and the incense burner is fitted into the heat-shielding wall hole, with its bottom exposed to the flame side of the interior space. Therefore, the bottom of the incense burner can be heated by both the convection heat of the flame and the radiant heat, allowing the incense burner to be heated sufficiently even when burning incense that requires a fairly high temperature. Moreover, since the bottom of the incense burner is easily affected by the heat of the flame, the temperature of the incense burner can be easily adjusted depending on the type of incense, for example, by increasing or decreasing the flame using the operating knob. Furthermore, even if a heat-shielding wall hole is formed to expose the bottom of the incense burner to the interior space, the incense burner is fitted into the heat-shielding wall hole, preventing convection heat from being directed toward the top plate.

[0013] Preferably, the burner has a burner head with a flame nozzle that releases the gas into the internal space, the burner head having a first bypass path and a second bypass path that guide the gas to the flame nozzle, the gas in the first bypass path and the gas in the second bypass path colliding directly below the flame nozzle, and the object to be heated is located above the collision area. This allows the gas (including the gas-air mixture) to slow down as it detours to the flame nozzle, and the detour path splits into the first and second bypass paths, further slowing the gas down. Furthermore, because the gas in the first bypass path and the gas in the second bypass path ultimately collide directly below the flame nozzle, their speed drops significantly, allowing the gas to be released from the flame nozzle in a flickering manner. This results in a flickering flame, similar to that of a fireplace. Furthermore, because the object to be heated is located above the area where the gases collide, the thermal effect on the object to be heated can be enhanced.

[0014] Preferably, the heat shield wall includes a first heat shield disposed relatively closer to the burner and a second heat shield disposed relatively closer to the top plate, the second heat shield having its edges connected to the inner surfaces of the four side surfaces of the housing, and the first heat shield having its edges bent diagonally to form inclined edges connected to the underside of the second heat shield so as to form an air layer between the first heat shield and the second heat shield, the inclined edges inclined toward the heat dissipation port. Therefore, the first and second heat shields, which are multiple layers, can effectively prevent heat transfer to the top plate. In this regard, the first heat shield has its inclined edge facing the heat dissipation port connected to the underside of the second heat shield, while the second heat shield has its edges connected to the inner surfaces of the four side surfaces of the housing. Therefore, the inclined edges of the first heat shield direct convection heat toward the heat dissipation port, while both the first and second heat shields prevent convection heat from being directed toward the top plate. Furthermore, since there is a layer of air between the first heat shield and the second heat shield, heat conduction from the first heat shield on the burner side to the second heat shield can be suppressed.

[0015] Preferably, the housing has an opening that connects the burner to the outside, and the opening area of ​​the opening is variable. This allows combustion air to be fed through the opening, and in this case, the fluctuation of the flame can be changed by following any change in the opening area of ​​the opening, without changing the amount of gas supplied to the burner. For example, by using the opening as an air adjustment means, the fluctuation can be changed without significantly changing the size of the flame.

[0016] The housing has a door that can be opened and closed to insert and remove the cassette gas cylinder, and the opening is located in the door. Therefore, the opening serves as a clue for opening and closing the door, and also serves as an air adjustment means that can change the flicker of the flame, as described above, killing two birds with one stone.

[0017] As described above, according to the present invention, it is possible to provide a flame viewing device that is small, allows for a wide range of installation locations, and prevents fires.

[0018] 1 is a perspective view of the front side of a flame observation device according to a first embodiment of the present invention (the flame is shown by a dot-dash line); FIG. 1 is a perspective view of the rear side of the flame observation device of FIG. 1; FIG. 2 is a view of the gas supply unit and the periphery of the burner of the flame observation device of FIG. 1 as seen from the rear side; FIG. 3 is a view of the periphery of the burner of the flame observation device of FIG. 1 as seen from the front side; FIG. 4 is a central vertical cross-sectional view taken along the longitudinal direction of the burner of the flame observation device of FIG. 1; FIG. 5 is a perspective view of the burner of the flame observation device of FIG. 1, with the upper half of the burner head omitted; FIG. 6 is a central vertical cross-sectional view taken along the width direction of the flame observation device of FIG. 1; FIG. 7 is a modified example of the incense burner and shielding wall of the flame observation device of FIG. 1; FIG. 8 is a perspective view of a flame observation device according to a second embodiment of the present invention; FIG. 9 is an exploded perspective view of the top plate and heat shielding wall of FIG. 9; FIG. 10 is a central vertical cross-sectional view taken along the A-A and B-B portions of FIG. 9; FIG. 9 is a view of the cylinder storage unit and burner with the door of FIG. 9 removed. 9A shows the opening in a closed state, FIG. 9B shows the opening in an open state, and FIG. 9C shows the opening as viewed from the inside. 13A shows a first modified example of the opening in FIG. 13. 13B shows a second modified example of the opening in FIG. 13.

[0019] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The embodiments described below are preferred specific examples of the present invention, and therefore various technically preferable limitations are applied. However, the scope of the present invention is not limited to these embodiments unless otherwise specified in the following description. Furthermore, components with the same reference numerals in the various drawings have the same configuration unless otherwise specified.

[0020] [Purpose of Flame Viewing Device 1] The flame viewing device 1 (hereinafter referred to as "device 1") according to the first embodiment of the present invention is small and light enough to be carried by one person. Its primary purpose is to allow viewers to enjoy the flickering flames of a fireplace in a variety of settings, regardless of the installation location, such as in the home, the entrance or guest room of a hotel or restaurant, or outdoors while camping. This fireplace-like flickering flame has a relaxing effect on the viewer and can also create a resort-like atmosphere in hotels and other locations. Furthermore, as described below, device 1 is equipped with an incense burner that utilizes the heat generated by the flames, and the resulting fragrance enhances the relaxing effect. Furthermore, since device 1 generates considerable heat from the flames, it also has a limited heating effect around device 1.

[0021] 1 and 2 includes a housing 10 having transparent portions 17 and 18, a burner 40 that releases gas into the internal space S1 of the housing 10, and a gas supply unit 60 that supplies gas to the burner 40. This allows a flame FR that is generated by igniting the gas released from the burner 40 within the housing 10 to be viewed through the transparent portions 17 and 18. Note that, in this embodiment, the gas supply unit 60 is disposed inside the housing 10 in consideration of portability and ease of handling, but the present invention is not limited to this and the gas supply unit 60 may be disposed outside the housing 10.

[0022] [Overview of the Structure of the Housing 10] The housing 10 completely surrounds the flame FR and includes a front panel 11, a back panel 12, left and right side panels 13 and 14, a top panel 15, and a bottom panel 16. In this embodiment, because both the front panel 11 and the back panel 12 have transparent portions 17 and 18, the front and back are not clearly distinguished from each other; the side indicated by reference numeral 12 in the figure may be considered the front panel, and the side indicated by reference numeral 11 may be considered the back panel. The housing 10 in the figure is generally rectangular, with a width W of approximately 30 cm, a depth D of approximately 10 cm, and a height H of approximately 30 cm. As such, the housing 10 is smaller than a typical fireplace, and is quite thin, with the depth D being approximately one-third of the width W.

[0023] The front panel 11 shown in FIG. 1 has a lower opaque portion 11A and an upper transparent portion 17. The opaque portion 11A is a hollow double-wall structure formed, for example, by applying a heat-resistant coating to steel. The transparent portion 17 is made of glass, and can be, for example, a known heat-resistant glass for wood stoves with a thickness of approximately 4 mm that can withstand temperatures of 500°C, but the present invention is not limited to this. This glass may be colorless, but may also have a slight tint, such as a light gray or warm color, to visually convey the warmth of the flame. In other words, the transparent portion 17 referred to in the present invention includes both colored and colorless portions as long as the flame inside the housing 10 can be visible from the outside. Furthermore, the front panel 11 has an edge portion 11B (hereinafter referred to as the "upper front edge portion") above the transparent portion 17, and this upper front edge portion 11B is formed with a heat radiator 75 for dissipating heat inside the housing 10 to the outside.

[0024] 2 also has a lower opaque portion 12A and an upper transparent portion 18. The transparent portion 18 is made of glass having the same configuration as the transparent portion 17 of the front panel 11. The opaque portion 12A is a door that can be opened and closed to insert and remove the cassette gas cylinder CB, and when this door is opened, the gas supply unit 60 is exposed. The rear panel 12 also has an edge portion (hereinafter referred to as the "upper rear edge portion") 12B above the transparent portion 18, and this upper rear edge portion 12B also has a heat dissipation port 75 formed therein to release heat from within the housing 10 to the outside.

[0025] The left and right side panels 13, 14 shown in Figures 1 and 2 are hollow double-wall structures formed, for example, by applying a heat-resistant coating to steel. The left and right side panels 13, 14 do not have any transparent portions. This allows the flame FR, even if the flame nozzle 42 of the burner 40 is elongated and thin, to be visible only from the front and / or rear, creating a voluminous flame, as described below. The left and right side panels 13, 14 also have heat vents 75 formed at the same height as the upper front edge 11A and the upper rear edge 12B (near the boundary with the top panel 15) for dissipating heat from within the housing 10 to the outside. An operating knob (also referred to as an "appliance valve knob") 19 is located on the right side panel 13. The operating knob 19 is connected to a known heat source controller 27 used in portable stoves and the like. The heat source controller 27 includes a flow control valve (not shown) that adjusts the opening and closing of the gas flow path and a governor 62, which is a pressure regulator. This allows the flow rate of gas supplied to the burner 40 (including zero) to be controlled by rotating the operating knob 19 .

[0026] The top plate 15 shown in FIG. 1 is made of, for example, steel with a heat-resistant coating. A through-hole is formed in a portion of the top plate 15 (the center in the figure), into which an incense burner 83 is removably inserted. The incense burner 83 will be described later. The bottom plate 16 shown in FIG. 2 is also made of, for example, steel with a heat-resistant coating. The bottom plate 16 has multiple through-holes 21. The through-holes 21 are air intakes for taking in primary air required to generate an air-fuel mixture in the burner 40 and secondary air required for the flame, and also serve to prevent heat from building up in the gas supply unit 60. Legs 23 are arranged at the four corners of the bottom plate 16, making it easier to take in air through the through-holes 21.

[0027] [Overview of the Gas Supply Unit 60] The gas supply unit 60 shown in FIG. 3 supplies gas to the burner 40 from an attached cassette gas cylinder (also referred to as a cartridge-type gas cylinder, hereinafter referred to as "cylinder") CB. It includes the heat source controller 27 and the cylinder housing 68. The cylinder CB is removably attached to the cylinder housing 68. The cylinder CB can be a known cylinder containing compressed liquefied gas. For example, a commercially available Iwatani Cassette Gas (trademark) containing approximately 250 g of liquefied butane compressed at a filling pressure of 0.2 MPa can be used. The attached cylinder CB can be connected to the cylinder connector 25. When the cylinder CB is connected and the operating knob 19 (see FIG. 1) is turned, the compressed gas inside is ejected and supplied to the burner 40 via the heat source controller 27 and the gas conduit 67. The cylinder connector 25 is attached to and detached from the cylinder CB by a magnet so that a safety mechanism is activated to disconnect the cylinder CB when the cylinder CB is heated and its internal pressure rises abnormally.

[0028] [Overview of Burner 40] As shown in Figures 3 and 4, the burner 40 includes a burner head 43 having a flame nozzle 42 that discharges a mixture of gas and primary air into the internal space S1, and a burner body (also referred to as a mixing tube) 45 having an outlet 41 that blows the mixture toward the burner head 43. As described above, gas is ejected into the burner body 45 from the gas cylinder CB via the gas conduit 67. The downstream end of the burner body 45 also includes a damper 45A that introduces primary air into the burner body 45. The burner body 45 also includes a throat 45B inside through which the mixture of primary air and gas passes, and a mixture chamber 45C located at the upstream end (tip). The outlet 41 that blows the mixture toward the burner head 43 is located at the tip of the mixture chamber 45C.

[0029] The burner head 43 has a flame nozzle 42 with numerous holes 32 formed therein, and the air-fuel mixture blown out from the outlet 41 of the burner body 45 toward the burner head 43 is discharged through these numerous holes 32 into the internal space S1. A spark plug 29 and a flame rod 28 are disposed near the flame nozzle 42. A known type can be used for the spark plug 29. Rotation of the operating knob 19 presses an igniter (not shown), generating a pulse voltage. This pulse voltage causes electrodes to discharge, igniting the gas discharged from the flame nozzle 42 and generating a flame. The flame rod 28 can also be a known type, and is a flame detector that flows current when a flame is present and recognizes that the flame has gone out when no current flows.

[0030] The burner 40 is the main burner, and the system also includes a pilot burner 46. The pilot burner 46 does not generate a pilot flame to ignite the main burner, but rather serves to prevent incomplete combustion beyond acceptable limits. Specifically, a gas conduit 67, which conducts gas ejected from a gas cylinder CB, branches into two branches: one branch is supplied to the main burner 40 and the other is supplied to the pilot burner 46. A known spark plug 47 is located near the nozzle 46A of the pilot burner 46, igniting the gas ejected from the nozzle 46A to generate a flame. A flame rod 48 is also located opposite the nozzle 46A. When the CO% of carbon monoxide in the housing increases (e.g., CO% is 0.02% or higher) and the oxygen concentration decreases, the combustion speed of the flame output from the pilot burner 46 slows, causing the flame to move away from the nozzle 46A. This prevents the flame from being detected by the flame rod 48, which then closes a solenoid valve (not shown) to shut off the gas. In this way, the pilot burner 46 of this embodiment can be said to be an incomplete combustion prevention device that prevents incomplete combustion that would cause the concentration of oxygen monoxide to exceed an allowable range.

[0031] It is preferable that such burners 40 and the like are made as difficult to see as possible, and as shown in Figure 1, they have a burner cover 24. The burner cover 24 is ring-shaped and bulges out toward the through-hole 24A in the central region. A space S2 is formed between the burner cover 24 and the burner 40. The space S2 is an intake port for secondary air, and is a hole for supplying air taken in through the through-hole 21 (see Figure 2) in the bottom plate 16 to the flame FR generated above the burner 40.

[0032] The device 1 is configured as described above and has the following additional features. Fig. 5 is a central vertical cross-sectional view of the burner 40, and Fig. 6 is a perspective view of the burner 40 with the upper half of the burner head 43 omitted (the dashed arrows indicate the flow of the air-fuel mixture MG). The burner 40 shown in these figures incorporates various features for generating a flickering reddish flame like that of a fireplace.

[0033] [Means for Generating a Reddish Flame] First, to generate a reddish flame (including reddish-yellow), the flame is made to undergo incomplete combustion. Incomplete combustion is achieved not by reducing the amount of secondary air, but by restricting the primary air used to generate the air-fuel mixture MG (including the case where the amount of primary air is zero). In this embodiment, incomplete combustion is achieved by reducing the opening area of ​​the primary air intake 37, which takes in primary air, in the damper section 45A of the burner body 45. As a result, although the flame of a normal portable stove is bluish, a flame color that resembles a mixture of red and yellow can be achieved.

[0034] In this regard, it is appropriate to set the CO% limit for carbon monoxide generated by incomplete combustion to not exceed 0.02% for three hours. That is, for commercially available cassette-type gas cylinders with limited capacity, such as those used in this embodiment, a maximum operating time of approximately three hours is expected, depending on usage. According to figures published by the Japan Gas Appliance Inspection Foundation, a CO% of less than 0.02% for this three-hour period is sufficient to prevent adverse effects such as headaches. Thus, because gas cylinders have a limited operating time, intentional incomplete combustion can be prevented from adversely affecting the human body. It is preferable to keep this CO% as low as possible. In this embodiment, the opening area of ​​the ginkgo-shaped, fan-shaped primary air intake 37 used in typical portable gas stoves (e.g., the Cassette Foo Tatsujin Slim™, product code CB-SS-50 manufactured by Iwatani Corporation) is blocked by approximately 90%, resulting in a CO% limit of approximately 0.004%, further enhancing safety.

[0035] [Means for Generating a Flickering Flame] Next, even if the flame color is reddish, a flame without flickering will not provide the relaxing effect of a fireplace. Therefore, a configuration is provided to generate a flame with a soft flickering (fluctuation). [Regarding the Collision Portion, etc.] First, a collision port 50 is provided inside the burner head 43, facing the outlet 41 that blows the air-fuel mixture MG toward the burner head 43, and against which the air-fuel mixture MG blown out from the outlet 41 collides. The collision port 50 in the figure is generally plate-shaped, formed larger than the opening area of ​​the outlet 41, and faces the outlet 41. This allows the momentum of the air-fuel mixture MG to be weakened even if it is forcefully ejected by compressed gas. Furthermore, a recess 36A recessed toward the burner body 45 is formed around the outlet 41 of the exterior body 36 of the burner head 43, making the space around the outlet 41 larger than the space of the gas flow path within the rest of the exterior body 36. This recess 36A receives a part or all of the air-fuel mixture MG after it collides with the collision target portion 50.

[0036] [Regarding the Detour Path] Secondly, the burner head 43 has a detour path RD that guides the air-fuel mixture MG around the collision target portion 50 to the flame nozzle portion 42 in order to slow down the flow velocity of the mixture. In this embodiment, the detour path RD branches off from the outlet 41 and includes a first detour path 53 and a second detour path 54 along which the air-fuel mixture MG flows in opposite directions. The distance of the first detour path 53 and the distance of the second detour path 54 in the figure are the same. The first and second detour paths 53 and 54 each have, from the downstream side, a separation path RD1 that guides the air-fuel mixture MG away from the outlet 41 after colliding with the collision target portion 50, and a U-turn path RD2 that detours around the ends 51 and 52 of the collision target portion 50 that are farthest from the outlet 41. Furthermore, downstream of the U-turn flow path RD2, the first detour path 53 has a first approach flow path RD3 through which the air-fuel mixture MG approaches the second detour path 54 located immediately below the flame nozzle portion 42 after going around one end 51 of the collision target portion 50. The second detour path 54 has a second approach flow path RD4 through which the air-fuel mixture MG approaches the first detour path 53 located immediately below the flame nozzle portion 42 after going around the other end 52 of the collision target portion 50. The first and second approach flow paths RD3, RD4 are arranged immediately below the flame nozzle portion 42, so that the air-fuel mixture MG1 flowing through the first detour path 53 and the air-fuel mixture MG2 flowing through the second detour path 54 collide immediately below the flame nozzle portion 42.

[0037] In this way, the burner head 43 can weaken the momentum of the mixture MG by the amount of branching, and furthermore, the collision of the mixture MG1 in the first detour 53 and the mixture MG2 in the second detour 54 can reduce the momentum. Furthermore, because the first approach flow path RD3 and the second approach flow path RD4 in the figure are on the same straight line, the mixtures MG flowing through these flow paths collide head-on directly below the flame port 42, more effectively reducing the flow velocity. Also, because the mixture MG1 via the first detour 53 and the mixture MG2 via the second detour 54 do not necessarily have the same momentum, the mixture MG that collides head-on may be pushed toward the first detour 53 at times and toward the second detour 54 at other times, depending on the difference in momentum, which leads to flame fluctuations.

[0038] In this way, in this embodiment, the air-fuel mixtures MG coming from different directions collide head-on, but the present invention is not limited to this as long as it is possible to weaken the momentum of the air-fuel mixture heading toward the nozzle 42. For example, the flow velocity heading toward the nozzle 42 can be reduced by forming multiple detours and blowing the air-fuel mixture from one detour from the nozzle 42 side (from above in FIG. 5) onto the air-fuel mixture from the other detour, causing them to collide. Also, in the figure, two detours are formed by branching from the outlet 41, but three or more detours may be formed.

[0039] The collision target portion 50 serves as a partition plate for forming the above-described detour paths, and will now be described. The collision target portion 50 extends in the X direction, which is perpendicular to the Z direction in which the air-fuel mixture MG is blown out from the outlet 41. It exists between the separation flow path RD1 and the first and second approach flow paths RD3 and RD4, separating these flow paths. Furthermore, with respect to one end 51 and the other end 52 of the collision target portion 50 in the X direction (the direction of extension), the central portions in the Y direction (thickness direction of the housing), which is perpendicular to both the X direction of extension and the Z direction of blowing, are bent downward. The bent portion 56 is connected to the lower inner surface 36B of the exterior body 36 of the burner head 43 so as to form spaces above and below the collision target portion 50. As a result, the space below the collision target portion 50 becomes the separation flow path RD1, and the space above becomes the first and second approach flow paths RD3 and RD4. Furthermore, a U-turn flow path RD2 is formed through which the mixture MG passes around from both sides of the central bent portion 56 at the ends 51 and 52 of the collision target portion 50. The mixtures MG passing around from both sides also collide with each other (see FIG. 6), and the flow velocity of the mixture MG also decreases in the U-turn flow path RD2.

[0040] Because this embodiment has the above-described flow paths, it is assumed that the air-fuel mixture MG forcefully blown out from the outlet 41 goes through a complex process before being released from the nozzle 42. That is, the air-fuel mixture MG slows down and becomes turbulent in the collision section 50, is straightened while slowing down slightly in the separation flow path RD1, is slowed down and becomes turbulent in the U-turn flow path RD2, is straightened while slowing down slightly in the first and second approach flow paths RD3 and RD4, and finally, the air-fuel mixture MG that has sufficiently slowed down is released from the nozzle 42, while the air-fuel mixture that has not yet slowed down collides with each other, further slows down, and is then released from the nozzle 42.

[0041] [Regarding the flame nozzle] Third, the flame nozzle 42 is formed of a porous material with many holes. The porous material may be a punched metal with many through-holes, but it is preferable to use a mesh-like material (i.e., a mesh material), as shown in the enlarged partial view of the flame nozzle 42 surrounded by the dashed line in Figure 5. A mesh material produced a soft flame. The mesh material in this embodiment is a plain woven wire mesh with a wire diameter of 0.29 mm. Note that the mesh material is not limited to a plain woven wire mesh, and may be, for example, a crimped wire mesh in which wires are crimped into a wavy shape.

[0042] Such a porous member is composed of multiple layers spaced apart in the height direction (Z direction), with the mesh positions of the first layer 42A and the second layer 42B offset in plan view. For example, as shown in the enlarged partial view enclosed by the dashed line in Figure 5, the second layer 42B does not have mesh at the same horizontal position as the mesh 39A of the first layer 42A, and even if it does exist, its shape is different. This increases the resistance of the mesh and creates a softer flame. Note that the mesh positions of the first layer 42A and the second layer 42B need only be offset generally, and some mesh positions may be in the same position. Furthermore, while the flame port 42 shown in the figure consists of two layers of mesh, it may also consist of one layer or three or more layers.

[0043] The above-described flame port portion 42 extends along the first approach flow path RD3 and the second approach flow path RD4, and as shown in FIG. 1 , the dimension in the width W direction is larger than the dimension in the thickness D direction of the housing 10. Therefore, this elongated flame port portion 42 effectively fluctuates the air-fuel mixture in the extension direction, generating a flickering flame FR. That is, as shown in FIG. 5 , when the airflows of the first approach flow path RD3 and the second approach flow path RD4 collide, the air-fuel mixture MG does not always collide midway between the first approach flow path RD3 and the second approach flow path RD4. Even after the collision, the air-fuel mixture MG may be released from the flame port portion 42 biased to one side or the other. Furthermore, some air-fuel mixture MG may be released from the flame port portion 42 before the collision. The flame port 42 is disposed directly above the first and second approach flow paths RD3 and RD4 so that this flow can be reflected.

[0044] [Means for Preventing Overheating of the Housing] Next, the means for preventing overheating of the housing 10 will be described using Figure 7. Figure 7 is a central longitudinal cross-sectional view of the device 1. Note that the cross section of the burner 40 has been omitted to avoid cluttering the drawing. The dashed arrows indicate the flow of convection heat HE. In the device 1, the housing 10 completely surrounds the flame FR, so unless some ingenuity is taken, heat will build up in the internal space S1, and the top plate 15 in particular will overheat. Therefore, it is necessary to prevent the risk of something falling from above and burning. Therefore, this embodiment has the following various configurations.

[0045] [About the Heat Shield Wall] First, a heat shield wall 73 is disposed above the burner 40 (specifically, the burner head 43) in the internal space S1 of the housing 10 to prevent the convection heat HE of the flame FR from being transmitted to the top plate 15 of the housing 10. The heat shield wall 73 is formed of steel with a heat-resistant coating. The heat shield wall 73 in this embodiment is composed of a first heat shield plate 71 and a second heat shield plate 72, with the first heat shield plate 71 being disposed on the burner head 43 side and the second heat shield plate 72 being disposed on the top plate 15 side.

[0046] The second heat shield 72 is located between the flame FR and the top plate 15, and its edges are joined to the inner surfaces of the four side surfaces of the housing 10 (in this embodiment, the front plate 11, rear plate 12, right side plate 13, and left side plate 14), completely separating the flame FR side space from the top plate 15 side space, except for the heat shield wall holes 80 described below. In contrast, the first heat shield 71 has an end 71A bent obliquely upward, and the edge of the bent end (inclined end) 71A or the edge beyond it is joined to the underside of the second heat shield 72. In this way, an air layer S3 is formed between the first heat shield 71 and the second heat shield 72, making it difficult for heat from the first heat shield 71 on the flame FR side to be transmitted to the second heat shield 72. Although the first and second heat shielding walls 71 and 72 in this embodiment are each formed from a single plate, the present invention is not limited to this, and for example, the second heat shielding wall 72 may be formed from two or more plates. Also, the heat shielding wall 73 may be made from a single plate by changing the material or coating thickness of the wall.

[0047] [Regarding the Heat Dissipation Ports] Second, heat dissipation ports 75 for dissipating heat from within the housing 10 to the external space are formed around the heat shield wall 73 on at least one of the four side surfaces of the housing 10 (in this embodiment, all four side surfaces shown in FIGS. 1 and 2 ). The heat dissipation ports 75 are elongated through-holes extending laterally and are located closer to the burner head 43 than the second heat shield plate 72 (at the same height as the inclined end portion 71A described below). The illustrated heat dissipation ports 75 are located in the upper front edge 11B, upper rear edge 12B, upper right edge 13B, which is the upper edge of the right side panel 13, and upper left edge 14B, which is the upper edge of the left side panel 14. As shown in FIG. 7 , the obliquely bent end (inclined end portion) 71A of the first heat shield wall 71 is inclined toward the heat dissipation port 75. Therefore, the convective heat HE is guided to the heat radiating openings 75 along the inclined end portions 71A of the heat shield wall 73. As shown in FIGS. 2 and 7 , the inclined end portions 71A are located on the front, rear, left, and right side surfaces of the first heat shield wall 71, and guide the heat HE to all of the heat radiating openings 75. Furthermore, because the heat radiating openings 75 are at the same height as the inclined end portions 71A, they can effectively radiate heat from the first heat shield wall 71, which is prone to overheating. Depending on the opening area, the heat radiating openings 75 do not need to be provided on all four side surfaces of the housing 10, and the opening area may vary depending on the location. For example, the heat radiating openings 75 (see FIGS. 1 and 2 ) on the front panel 11 and / or back panel 12, which have the transparent portions 17 and 18, may be larger than the heat radiating openings 75 on the left and right side panels 13 and 14, so that heat can be supplied to a user viewing the flame FR through the transparent portions 17 and 18.

[0048] [About the Heated Object] Third, as shown in Figures 1 and 7, the device 1 includes a heated object 83 that concentrates heat within the housing 10 as much as possible at a specific location, thereby effectively suppressing heating of the top plate 15 and all four side surfaces. The heated object 83 utilizes the heat of the flame FR. For example, this could be a water container for humidifying a room. In the present invention, this could also be a humidifying water container. However, since water does not reach temperatures above 100°C, it does not effectively suppress heating of the top plate 15 and all four side surfaces, and there is also a risk of spilling water during transport. Therefore, the heated object 83 is preferably an object that is heated using heat at a temperature at least higher than the heat radiation temperature from the heat radiation vent 75. In this embodiment, an incense burner is used. The heated object, the incense burner 83, requires a temperature of approximately 150°C to 200°C, depending on the type of incense placed inside, a temperature that allows sufficient concentration of heat within the housing 10 without causing any problems. As a result, in this embodiment, the temperature of the top plate 15 can be kept below 100 degrees, and the heat radiation temperature of the heat radiation port 75 can be kept at approximately 100 degrees.

[0049] The incense burner 83 is detachable from the housing 10. The incense burner 83 includes a separable incense burner body 85 and a lid 86. In this embodiment, the entire incense burner is made of steel. However, the incense burner body 85 may be made of a metal with good thermal conductivity, such as iron plate, and the lid 86 may be made of ceramic with poorer thermal conductivity. The incense burner body 85 can also be called an incense burner tray, and its inner space S4 is a storage container for non-flammable incense, such as fragrant wood, powdered incense, fragrant herbs, incense seals, and kneaded incense, or aromatic oils. These incense products also have a relaxing aroma, further enhancing the relaxing effect of viewing the flame. While the incense burner body 85 shown in the figure has a cylindrical outer surface, it may be elongated to match the shape of the flame nozzle 42. The lid 86 covers the upper opening of the incense burner body 85 and has multiple through-holes 86A to effectively release the aroma when heated. A finger can be inserted into the largest through-hole 86A, making it easy to remove the lid.

[0050] This incense burner 83 has the following configuration to achieve a maximum temperature of the incense burner body 85 of approximately 200°C. First, a top plate hole 15A, which is a through-hole penetrating the top plate 15 in the thickness direction, is formed, allowing the incense burner body 85 to be inserted into this top plate hole 15A. Specifically, as shown in the enlarged partial view of the incense burner 83 surrounded by the dashed line in Figure 7, the peripheral portion 15B of the top plate hole 15A is recessed from the remaining surface of the top plate 15. The upper flange portion 85A of the incense burner body 85 is then placed and engaged on the upper surface of this peripheral portion 15B. As a result, most of the incense burner body 85 is positioned below the top plate 15, allowing the heat to be utilized before it is transferred to the top plate 15 (conversely, the temperature of the top plate 15 can be reduced accordingly).

[0051] The heat shield wall 73 also has a heat shield wall hole 80, which is a through-hole that penetrates the wall in the thickness direction. The heat shield wall hole 80 in the figure is a through-hole 82 in the first heat shield plate 71 and a through-hole 81 in the second heat shield plate 72, which are formed continuously in the thickness direction. In this way, at least the bottom surface 85B of the incense burner 83 is exposed to the internal space S1 on the flame FR side, and the bottom surface 85B is directly exposed to the convection heat HE of the flame FR and is also heated by radiant heat, thereby sufficiently heating the incense burner 83. Furthermore, since the bottom surface 85B of the incense burner 83 is exposed to the internal space S1, it is easily affected directly by the heat of the flame FR. Therefore, by operating the operating knob 19, the flame FR can be made larger (FR2) or smaller (FR1) as shown in the figure, making it easy to change the temperature of the incense burner 83 depending on the type of incense.

[0052] As described above, the air-fuel mixture MG in the first bypass 53 and the air-fuel mixture MG in the second bypass 54 shown in FIG. 5 collide directly below the flame nozzle 42, and as shown in FIG. 7, the incense burner 83 is positioned above the collision area AR. This allows the incense burner 83 to be heated more effectively. It is preferable to fit the incense burner 83 into the heat shield wall hole 80 to prevent the convection heat HE of the flame FR from being directed toward the top plate 15. Preferably, the incense burner 83 is fitted into both the through-hole 82 of the first heat shield plate 71 and the through-hole 81 of the second heat shield plate 72 to prevent the convection heat HE from being transmitted to the top plate 15.

[0053] The present invention is not limited to a configuration in which the bottom surface 85B of the incense burner 83 is exposed to the internal space S1. For example, the configuration shown in FIG. 8 may be used. FIG. 8 is a longitudinal cross-sectional view of a modified example of the incense burner 83 and its surroundings. This figure differs from the above-described embodiment in terms of the incense burner 83 and the heat shield wall 73. In other words, in this modified example, of the first and second heat shield plates 71 and 72 constituting the heat shield wall 73, the first heat shield plate 71 exposed on the flame side (the area of ​​the heat shield wall 73 exposed to the internal space S1 on the flame side) does not have a through-hole. The heat shield wall 73 completely separates the flame-side space from the top plate 15-side space (except for small gaps) with the first and second heat shield plates 71 and 72, allowing essentially all of the convective heat HE shown in FIG. 7 to be released to the outside through the heat radiator 75. Furthermore, as shown in FIG. 8, the bottom surface 85B of the incense burner 83 contacts the upper surface 71B of the first heat shield plate 71. This facilitates the transfer of heat from the first heat shielding plate 71 to the incense burner 83, facilitating the collection of heat to the incense burner 83. In other words, since almost all convection heat is released from the heat radiating holes, heat is mainly transferred to the top plate 15 by thermal conduction from the heat shielding wall 73 and the four side surfaces, but since the incense burner 83 is in contact with the heat shielding wall 73, heat tends to concentrate on the incense burner 83. When incense is burned in the incense burner 83, the concentrated heat is consumed, effectively preventing the top plate 15 in contact with the incense burner 83 from overheating.

[0054] Next, a flame observation apparatus 100 according to a second embodiment of the present invention will be described with reference to Figures 9 to 13. Figure 9 is a perspective view of the flame observation apparatus 100, Figure 10 is an exploded perspective view of the top plate 15 and heat shield wall 110 of the flame observation apparatus 100, Figure 11 is a central vertical cross-sectional view taken along lines A-A and B-B in Figure 9, Figure 12 is a view of the cylinder storage section 68 and burner 150 with the door 160 removed in Figure 9, and Figure 13 is a diagram illustrating the opening 170 in Figure 9. Note that in Figures 9 to 13, components with the same reference numerals as those in the flame observation apparatus 1 described above have substantially the same configuration, and the following description will focus on the differences. The flame observation apparatus 100 in these figures differs mainly from the flame observation apparatus 1 in Figures 1 to 8 in the heat shield wall 110, the heat vent 130, the burner 150, and the door 160 for inserting and removing the cylinder CB.

[0055] [About the Heat Shield Wall and Heat Dissipation Vent] First, the heat shield wall 110 and the heat dissipation vent 130 will be described mainly with reference to Figures 9 to 11. The heat shield wall 110 does not have the first heat shield wall 71 on the burner side shown in Figure 7, and is composed of only one layer as shown in Figure 11. As in the first embodiment, the heat shield wall 110 has a through-hole 81 into which an incense burner 83 is inserted, and not only the bottom surface 85B of the incense burner 83 but also the lower portion 85C on which incense, aromatic oils, etc. are placed are exposed to the internal space S1. This makes it easier for incense, etc. to be heated.

[0056] The main surface of the heat shield wall 110 is flat, and as in the first embodiment, the heat dissipation vents 130 are located around the heat shield wall 110. Therefore, convective heat impinging on the heat shield wall 110 spreads horizontally and is guided to the heat dissipation vents 130. However, because the heat shield wall 110 does not have the inclined end portion 71A of the first heat shield wall 71 shown in FIG. 7 , it is difficult to guide the convective heat HE to the heat dissipation vents 130. Therefore, the opening area of ​​the heat dissipation vents 130 in the second embodiment is larger than that of the first embodiment, making it easier for the convective heat HE to escape to the outside. Furthermore, the heat dissipation vents 130 are positioned at the same height as the lower portion 85C of the incense burner 83, where incense, aroma oils, etc. are placed. By increasing the opening area of ​​the heat dissipation vents 130 and positioning the heat dissipation vents 130 at the same height as the lower portion 85C of the incense burner 83, overheating of the top plate 15 can be effectively prevented. In the second embodiment, the temperature of the top surface of the tabletop 15, excluding the area around the incense burner 83, could be kept below approximately 100°C, and even down to the 80°C range depending on the measurement location. While a larger heat dissipation port 130 can prevent the tabletop 15 from overheating, a larger port size is not desirable because it can adversely affect the flame due to wind, result in insufficient heating of the incense burner 83, and increase the size of the housing 10. The area of ​​the heat dissipation port 130 can be determined taking into account its position and shape, the type and pressure of the gas, the type and size of the burner 150, the type and size of the object to be heated (the incense burner 83 in this embodiment), and the material and size of the housing 10.

[0057] In the first embodiment, the heat dissipation vent 75 was formed in the top plate 15 as shown in Fig. 1 , but in the second embodiment, as shown in Figs. 10 and 11 , the heat shield wall 110 has a frame-shaped side portion 112 with four edges extending downward (towards the burner) like a cover, and the heat dissipation vent 130 is formed in this side portion 112. This makes it difficult for the ambient temperature of the heat dissipation vent 130, which is heated by the passage of hot air, to be transferred to the top plate 15. The top plate 15 has a protrusion 114 that protrudes downward from a part of its periphery, and this protrusion 114 is inserted into a through hole 116 in the periphery of the heat shield wall 110, and this protrusion 114 and the side portion 112 of the heat shield wall 110 are connected by a connecting member 118 such as a screw or a bolt.

[0058] [Burner, etc.] Next, a burner 150 and other components will be described with reference to FIG. 12 . Like the first embodiment, the burner 150 includes a burner head 43 with a flame nozzle 42 and a burner body 152 that blows the air-fuel mixture toward the burner head 43. The burner head 43 has a similar configuration to that of the first embodiment, except that its overall thickness is thinner than that of the first embodiment. While the burner body 152 was horizontal in the first embodiment, it is vertical in the second embodiment, shortening the throat portion 152A through which the primary air and gas mixture passes inside. This shortens the time from operating the operating knob 19 (see FIG. 1 ) to ignition and extinguishing. In this embodiment, ignition and extinguishing are possible in approximately two seconds after operation.

[0059] As described above, the burner 150 has a small overall volume. In this case, in order to generate a fluctuating flame, it is preferable to reduce the pressure of the gas supplied to the burner 150 in proportion to the volume. In the second embodiment, the pressure of a typical portable portable stove (e.g., Cassette Foo Tatsujin Slim (trademark) product code CB-SS-50 manufactured by Iwatani Corporation) is approximately 7.2 KPa, but by adjusting the governor 62, etc., the pressure is reduced to approximately 2.94 KPa. Note that the primary air intakes 141 of the burner body 152 are formed on the side and bottom surfaces, and because a reddish-colored flame (including reddish-yellow) is generated due to incomplete combustion, approximately 90% or more of the opening area of ​​the primary air intake 37 used in the above-mentioned typical portable portable stove is blocked, as in the first embodiment.

[0060] [Regarding the Door for Inserting and Removing a Cassette Gas Cylinder] Next, the door 160 for inserting and removing the cylinder CB will be described with reference to Figures 9, 12, and 13. As shown in Figure 12, the housing 10 has a cylinder storage section 68 for detachably mounting the cylinder CB. As shown in Figure 9, this cylinder storage section 68 is covered with a door 160 that can be opened and closed to insert and remove the cylinder CB. The door 160 can be opened and closed by rotating in the RL direction on an axis of a lower portion 160A. An opening 170 is formed in the door 160. The opening 170 is a communication section that connects the burner to the outside (in other words, a through hole that spatially connects the space surrounding the burner with the outside), and serves to adjust the amount of air used for combustion and to open the door 160.

[0061] In Figure 9, the opening 170 is shown in a state where it is roughly half-closed by the variable mechanism 135, which can change the opening area. The variable mechanism 135 slides up and down to open and close the opening 170 in stages or gradually, as shown in Figure 13(A) when the opening 170 is closed and in Figure 13(B) when the opening 170 is open. Specifically, as shown in Figure 13(C), the variable mechanism 135 comprises a plate-shaped member 129 and a guide 137 that regulates the movement of the plate-shaped member 129. The illustrated guide 137 is located on the back (inside) of the door, on the left and right sides of the opening 170, and has grooves 137A running vertically. The left and right ends of the plate-shaped member 129 fit into these grooves 137A, allowing the plate-shaped member 129 to slide vertically along the grooves 137A. This allows the amount of combustion air to be freely changed and the flame fluctuation to be altered without changing the amount of gas sent to the burner.

[0062] This adjustment means 135 is provided with a knob 146 that protrudes outward from the plate-like member 129, and the plate-like member 129 can be easily slid using the knob 146 as a handle. When opening the door 160 in Figure 9, the knob 146 can be pinched and pulled, or a finger can be inserted into the opening 170 and pulled. Note that the adjustment means 135 in the figure slides up and down, and therefore the opening 170 is vertically long accordingly, but the adjustment means 135 may also be structured to slide left and right, in which case the opening 170 should be horizontally long.

[0063] The variable means may also have the configuration shown in Fig. 14. The variable means 180 in Fig. 14 is a cover that can cover the entire opening 170, and is detachable from the door 160 by means of attachment / detachment means 159 such as a magnet. When the variable means 180 is removed, the opening 170 is fully opened, and conversely, when it is attached to the door 160 so as to cover the entire opening 170, the opening 170 is closed. The variable means 180 can also be attached to the door 160 at any position so that part of the opening 170 is exposed to the outside. In this way, the opening area of ​​the opening 170 can be freely changed.

[0064] The variable means may also have the configuration shown in FIG. 15 . The hatched portion in FIG. 15 is the opening 172. In other words, in FIG. 15 , the variable means 155 is rotated to open or close the opening 172 in a stepwise or gradual manner. Specifically, the variable means 155 includes, for example, a semicircular plate-like member 132 having a rotation axis CL and a knob 133 protruding outward from the plate-like member 132, and is rotatable in the R direction by turning the knob 133. In contrast, the opening 172 is a through-hole (a semicircular hole in the illustrated example) formed within the range of rotation of the variable means 155. Note that, in this configuration in which the opening area is changed by rotation, the plate-like member 132 and the opening 172 are not limited to being semicircular in shape and may be, for example, rectangular, elliptical, or have a complex shape.

[0065] The present invention is not limited to the above-described embodiment and various modifications may be made without departing from the scope of the claims. The configurations of the above-described embodiment may be partially omitted or arbitrarily combined differently. For example, while the burner of the above-described embodiment discharges a mixture of gas and primary air into the internal space of the housing, the present invention is not limited to this configuration. In the present invention, if the significant adverse effects of carbon monoxide concentration on the human body can be avoided by adjusting various specifications such as the size of the housing, the size and number of through-holes in the bottom plate, or the gas combustion time, the primary air intake of the burner body may be completely blocked (without forming the primary air intake 37 shown in Figures 4 to 6), and the fluid from the burner body 45 to the flame nozzle 42 via the bypass route RD shown in Figure 5 may be almost entirely gas (a gas that is not a mixture without primary air). This reduces the flow rate of the fluid within the burner 40 of Figure 5 compared to the above-described embodiment, and the gas flow rate can be reduced if the cross-sectional area of ​​the flow path of the burner 40 is the same, making it easier to generate a more fluctuating flame.

[0066] REFERENCE SIGNS LIST 1: Flame viewing device, 10: Housing, 15: Top plate, 15A: Top plate hole, 17, 18: Transparent portion, 40: Burner, 42: Flame mouth portion, 43: Burner head, 71: First heat shield plate, 72: Second heat shield plate, 73: Heat shield wall, 75: Heat radiator port, 53: First bypass path, 54: Second bypass path, 83: Heated object (incense burner), CB: Cassette gas cylinder, RD: Bypass path, S1: Internal space, MG: Gas (air-fuel mixture)

Claims

1. A flame observation device having a housing with a transparent part and a burner that releases gas into the internal space of the housing, and allowing the flame produced by burning the gas to be observed through the transparent part, wherein the gas is supplied from a detachable cassette gas cylinder, a heat insulating wall is arranged above the burner in the internal space to prevent convection heat from the flame from being directed toward the top plate of the housing, and at least one of the four side surfaces of the housing has a heat release port around the heat insulating wall for releasing the convection heat to the external space.

2. A flame viewing device as described in claim 1, characterized in that a heated object is provided on the top plate side, which is heated using heat of a temperature higher than the heat radiation temperature from at least the heat radiation port.

3. The flame viewing device according to claim 2, wherein the object to be heated is an incense burner, the top plate has a top plate hole that is a through hole that penetrates through the thickness direction, and the incense burner is inserted into the top plate hole.

4. The flame viewing device described in claim 3, characterized in that the heat insulating wall separates the flame-side space from the top-plate-side space without forming a through-hole in the area of the internal space exposed to the flame side, and the bottom surface of the incense burner contacts the top surface of the heat insulating wall in the area of the internal space exposed to the flame side.

5. A flame viewing device as described in claim 3, characterized in that the heat insulating wall has a heat insulating wall hole that is a through hole that penetrates through the heat insulating wall in the thickness direction, and the incense burner is fitted into the heat insulating wall hole so that its bottom surface is exposed to the flame side of the internal space.

6. The flame observation device described in claim 5, characterized in that the burner has a burner head with a flame nozzle that releases the gas into the internal space, the burner head has a first detour path and a second detour path that guide the gas in a detour to the flame nozzle, the gas in the first detour path and the gas in the second detour path collide directly below the flame nozzle, and the heated object is positioned above the area of collision.

7. A flame viewing device as described in any one of claims 1 to 6, characterized in that the heat shield wall has a first heat shield plate arranged relatively closer to the burner and a second heat shield plate arranged closer to the top plate, the edges of the second heat shield plate are connected to the inner surfaces of the four side surfaces of the housing, the ends of the first heat shield plate are bent diagonally to form inclined ends, and the first heat shield plate is connected to the underside of the second heat shield plate so as to form a layer of air between it and the second heat shield plate, and the inclined ends are inclined towards the heat dissipation port side.

8. A flame observation device according to any one of claims 1 to 6, characterized in that the housing has an opening that connects the burner to the outside, and the opening area of the opening is variable.

9. A flame viewing device as described in claim 8, characterized in that the housing has a door that can be opened and closed to insert and remove the cassette gas cylinder, and the opening is located in the door.

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