JP2000018566A - Combustion apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrict a rise in temperature within a casing even when an air feed pipe and an exhaust pipe are too long. SOLUTION: This apparatus houses an enforced ventilation type combustion 1a in a casing 10 installed indoors. In this case, this apparatus includes an air feed pipe 3 which is connected to the casing 10 while being designed to guide feed air from outdoors into the casing 10, an exhaust pipe 4 which is inserted through the air feed pipe 3 to be connected to the combustion 1a while being designed to guide an exhaust outside from the inside of the combustion 1a and a cover pipe 5 which covers the exhaust pipe 4 so as to form an air layer between the pipe and the exhaust pipe while being designed to form a path 30 for feed air between it and the air feed pipe 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion apparatus, and more particularly to a combustion apparatus in which an air supply pipe guides air supply from the outside into a casing installed indoors and an exhaust pipe inserted into the supply pipe from a combustor in the casing. The present invention relates to a combustion device that guides exhaust gas to the outdoors.

[0002]

2. Description of the Related Art FIG. 7 is a diagram showing an outline of the configuration of a conventional water heater (9). The water heater of the same figure as the above combustion device
(9) is a combustor mounted on the casing (9a) installed on the indoor wall.
(9b). The above combustor (9b)
Has a built-in burner (91) and this burner (91)
A heat exchanger (90) for hot water supply heated by the air supply, an air supply fan (92) for feeding air supply in the casing to the burner (91), and an exhaust gas passing through the heat exchanger (90) are collected and exhausted. An exhaust collector (93) having an outlet (94).

[0003] The water heater (9) has a casing.
Air supply pipe (9c) connected to (9a) and penetrating the wall (8)
And an exhaust pipe (9d) inserted into the air supply pipe (9c) and connected to the exhaust outlet (94). Therefore, the supply air is guided from the outside into the casing (9a) by the supply pipe (9c), and the exhaust is guided from the exhaust outlet (94) to the outside by the exhaust pipe (9d).

In this device, an air supply pipe (9) penetrating a wall (8) is provided.
Since the exhaust pipe (9d) is inserted through c), these air supply pipes
(9c) and the exhaust pipe (9d) are separately arranged in parallel, and the construction is simpler than that in which the exhaust pipe (9d) penetrates the wall (8).

[0005]

However, the air supply pipe (9c)
Since the exhaust pipe (9d) is inserted through the inside, the high-temperature exhaust (for example, 200 ° C.) passing through the exhaust pipe (9d) and the air supply pipe (9
The supply air passing through the supply passage between c) and the exhaust pipe (9d) exchanges heat with each other, and the supply air temperature rises. Therefore, the temperature in the casing (9a) into which the supply air is sucked rises.

The air supply pipe (9c) and the exhaust pipe (9d) are relatively long (for example, due to the installation location of the water heater (9)).
3m), the amount of heat exchange between the exhaust and the supply air increases, and the amount of increase in the temperature inside the casing (9a) increases. Therefore, the electronic components (9
6) and the like are overheated, and this water heater (9) is liable to break down.

SUMMARY OF THE INVENTION It is an object of the present invention to suppress a rise in temperature in a casing even if an intake pipe and an exhaust pipe are long. [1]

[0008]

Means for Solving the Problems To solve the above-mentioned problems, a solution of the present invention is a "combustion device in which a forced supply / exhaust type combustor is housed in a casing installed indoors. An air supply pipe connected to the casing and for introducing air supply from outside into the casing; and an air supply pipe inserted into the air supply pipe and connected to the combustor to guide exhaust air from the combustor to the outside. And a cover pipe that covers the exhaust pipe so as to form an air layer with the exhaust pipe and forms the air supply passage between the exhaust pipe and the exhaust pipe. It is characterized by having ”.

In this device, the supply air is guided from the outside into the casing by the supply pipe, and the exhaust gas is guided from the inside of the combustor to the outside by the exhaust pipe. At this time, there is a cover pipe which covers the exhaust pipe to form an air supply passage between the exhaust pipe and the air supply pipe, and an air layer is formed between the cover pipe and the exhaust pipe. The heat exchange between the exhaust gas in the exhaust pipe and the air supply in the air supply passage is suppressed by the heat insulation effect and the heat insulation effect by the cover pipe itself.

The cover pipe may cover a part of the exhaust pipe in the direction in which the exhaust pipe extends, or may cover the entire exhaust pipe.

[0011]

According to the present invention, as described above, since the heat exchange between the air supply and the exhaust is suppressed, the temperature rise in the casing into which the air is sucked is suppressed even if the air supply pipe and the exhaust pipe are long. . Therefore, the electronic components and the like in the casing are not overheated, and the failure of the combustion device is prevented.

Further, since the heat exchange between the supply air and the exhaust gas is suppressed, the cooling of the exhaust gas is suppressed, and thereby, the generation and adhesion of the drain on the inner surface of the exhaust pipe are suppressed. Therefore, corrosion of the exhaust pipe due to drainage is suppressed. Further, when installing the air supply pipe and the exhaust pipe, the above-described heat insulating structure is obtained by simply covering the exhaust pipe with the cover pipe. Therefore, the installation work is more efficient than the method of applying or winding a heat insulating material on the exhaust pipe. It becomes something.

The cover pipe has a structure in which an air layer is formed between the cover pipe and the exhaust pipe. The cover pipe is covered with a sufficient margin, so that the operation of covering the cover pipe on the exhaust pipe is simple. Therefore, also in this respect, the installation work becomes efficient. [2] In the above item 1, it is preferable that "the air supply pipe, the exhaust pipe and the cover pipe are each a bellows-shaped flexible pipe".

In this case, since the air supply pipe, the exhaust pipe and the cover pipe are each a bellows-shaped flexible pipe, they can be adapted to various installation places by bending them.
In this device, since the exhaust pipe and the cover pipe have bellows, respectively, when the exhaust pipes and the cover pipes having different diameters come into contact with each other, the minimum diameter portion of the cover pipe comes into point contact with the outer peripheral surface of the exhaust pipe. Thus, the air layer is reliably formed between the two.

Furthermore, since the cover tube has a bellows shape, the cover tube has a larger surface area than a straight tube, and the heat insulation area of the cover tube itself increases. Therefore, also at this point, the heat exchange is suppressed, and the temperature rise in the casing is suppressed.
The bellows shape may be a shape in which the peaks are arranged in parallel or a shape in which the peaks extend in a spiral shape.

[3] In the above item [1] or [2], in the above-mentioned "the casing has a configuration in which a portion other than a connection portion with the air supply pipe is airtight", Because air does not flow into the casing from
There is no cooling effect in the casing due to the inflow air. Therefore, the necessity of the effect of suppressing the temperature rise in the casing by the above-described cover tube becomes particularly remarkable.

Further, since the casing is configured to be airtight at portions other than the connection portion with the air supply pipe, even when the casing is installed in a place such as a bathroom which is easily wetted by water, water or steam is contained in the casing. Do not invade. Therefore, also in this respect, the failure of the combustion device is prevented. [4] In the above items [1] to [3], wherein the “air supply pipe is connected to an air supply opening formed in the casing, and the exhaust pipe is connected to the combustor located in the casing. Connected to an exhaust outlet, and the cover pipe is placed over the exhaust pipe in a direction in which the exhaust pipe extends from the exhaust outlet. " The exhaust pipe is connected to an exhaust outlet of a combustor located in the casing. From these facts, the uppermost stream of the exhaust pipe is not covered by the air supply pipe, but is exposed in the casing. In this state, heat is directly conducted from the uppermost stream of the exhaust pipe into the casing.

However, the exhaust pipe is covered with a cover pipe over the direction in which the exhaust pipe extends from the exhaust outlet, and the uppermost stream portion of the exhaust pipe is surrounded by the cover pipe.
Due to the heat insulating effect of air between the two and the heat insulating effect of the cover tube itself, heat conduction from the most upstream portion into the casing is suppressed. Therefore, also at this point, the temperature rise in the casing is suppressed.

[5] The method according to the above [4], wherein "the casing is a wall-mounted type, and the combustor is provided with an air supply fan and a burner connected to an upper end of the air supply fan. A burner box, a hot water supply heat exchanger connected to an upper end of the burner box, and an exhaust collecting part connected to an upper end of the hot water supply heat exchanger and having the exhaust outlet; The air outlet is formed in an upper surface plate of the casing, the exhaust outlet is formed at a position facing the air supply port in the exhaust collector, and the air supply pipe is provided with the air supply port. The exhaust pipe is detachably connected to the exhaust outlet, the exhaust pipe is detachably connected to the exhaust outlet, the second air supply port formed in the back plate of the casing, and the exhaust pipe in the exhaust collecting section. A second exhaust outlet formed at a position facing the second air supply port; And a lid detachably attached to the mouth and the second exhaust outlet, wherein the lid is removed from the second air supply opening and the second exhaust outlet. And the air supply pipe and the exhaust pipe can be detachably mounted on the air supply port and the exhaust outlet from which the air supply pipe and the exhaust pipe have been removed. "

In this device, the air supply pipe is detachably connected to an air supply port formed on the upper surface plate of the casing, and the exhaust pipe faces the air supply port in the exhaust gas collecting section. It is detachably connected to an exhaust outlet formed at the position. Therefore, in this upper air supply / exhaust connection state,
The heat exchange between the exhaust gas in the exhaust pipe and the air supply in the air supply passage is suppressed by the cover pipe, and the temperature rise in the casing is suppressed.

Further, in this case, when the upper supply / exhaust air is connected, a second air supply port formed in the back plate of the casing and the second air supply in the exhaust gas collecting section are provided. A lid is detachably attached to a second exhaust outlet formed at a position facing the opening. The lid is removed from the second air supply port and the second air outlet in the connection state of rear air supply and exhaust, and the upper side of the state where the air supply pipe and the exhaust pipe are removed. It is detachably attached to the air supply opening and the exhaust outlet.

In this state, an air supply pipe or the like extending outside is connected to the second air supply port, and an exhaust pipe or the like extending outside is connected to the second exhaust outlet. Supply air into the casing and exhaust air from the exhaust outlet to the outside. Therefore, the upper supply / exhaust method and the rear supply / exhaust method can be easily switched, and the combustion device for the upper supply / exhaust and the combustion device for the rear supply / exhaust can be shared.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described.
This will be described with reference to the drawings. 1 is a front view of a water heater according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line II-II of the water heater of FIG. 1, and FIG. 3 is a sectional view of the water heater of FIG. FIG. 3 is a front view of the casing (10) with a front cover (10a) removed. FIG. 4 is an explanatory view of assembling an air supply pipe (3), an exhaust pipe (4) and a cover pipe (5) of the water heater of FIG. 3, and FIG. 5 is a casing in the water heater of FIG. (10) and an enlarged sectional view of the upper end of the combustor (1a). FIG.
FIG. 4 is an enlarged cross-sectional view of the casing (10) and the upper end of the combustor (1a) when the water heater is a rear exhaust type.

This water heater, as shown in FIGS.
The casing (10) installed on the indoor wall has a configuration in which a forced air supply type combustor (1a) is housed. And this water heater has an air supply pipe (3) that is connected to the casing (10).
An exhaust pipe (4) inserted into the air supply pipe (3) and connected to the combustor (1a), and a cover pipe (5) covered by the exhaust pipe (4). ing.

[Regarding the Configuration of Each Part] * Casing (10) * The casing (10) is formed in a hollow rectangular parallelepiped shape, and is attached and fixed to a wall (8) as shown in FIG. I have. As shown in FIGS. 4 and 5, the casing (10) includes a back plate and a bottom plate, and a support plate (10b) to which a main part of a combustor (1a) described later is attached. The casing is protruded in the middle of the upper edge of the support plate (10b).
A projecting plate (10c) constituting a part of the top plate of (10); a supporting plate (10b) and a projecting plate constituting the side plate, the front plate and the other part of the top plate of the casing (10); (10c) and a cover body (10a) for covering the entire front side of (10c).

FIGS. 4 and 5 show the protruding plate (10c).
As shown in FIG. 5, an opening (101) is formed, and a cylindrical body (100) is provided to stand upright from the periphery of the opening (101). As shown in FIG. 4, the cylindrical body (100) is fixed to the projecting plate (10c) by screwing a flange portion (100a) projecting from the lower end thereof to the projecting plate (10c). The air supply port formed by the opening (101) and the cylindrical body (100) serves as a connection portion with the air supply pipe (3) described later.

As shown in FIG. 5, an opening (102) is formed in the upper part of the support plate (10b).
Is hermetically closed by a lid (2) described later.
Further, the cover (10a), the support plate (10b) and the protruding plate (10c)
Packing (not shown) is interposed between each other,
Thereby, the opening (101) in this casing (10)
The parts except for are airtight.

* Combustor (1a) * The above-mentioned combustor (1a) has a casing as shown in FIG.
(10), a burner box (13) connected to the upper end of the supply fan (11) and containing a burner (12), and a burner box (13). ), And a heat exchanger (14) for hot water supply connected to the upper end of the hot water supply. Note that the heat exchanger (14) is a rectangular cylindrical peripheral wall through which a combustion gas (exhaust gas) from the burner (12) passes through a water pipe having fins (not shown).
(14a).

As shown in FIGS. 3 and 4, the combustor (1a) has a lid (16) covering the entire upper end of the heat exchanger (14).
And a forked pipe (17) attached to the center of the lid (16), and the lid (16) and the forked pipe (17) exhaust the exhaust gas from the heat exchanger (14). It becomes an exhaust collecting part to be collected. As shown in FIG. 5, the bifurcated pipe (17) has an upper exhaust outlet (111) composed of a tubular part that opens upward and a rear exhaust outlet (112) composed of a tubular part that opens backward. Provided. The upper exhaust outlet (111) is located at a position facing the opening (101), and the rear exhaust outlet (112) is located at the opening (10).
2) It is in a position facing.

Further, the combustor (1a) has a control circuit for controlling gas supply to the burner (12), water supply to the heat exchanger (14), hot water temperature from the heat exchanger (14), and the like. And an electric component (18) constituting a power supply unit and the like. These electrical components
Each of the components (18) is composed of various electronic / electric components and the like, and all of the electrical components (18) are arranged in the casing (10).

* Air supply pipe (3), exhaust pipe (4) and cover pipe
(5) * The air supply pipe (3), the exhaust pipe (4) and the cover pipe (5) are all bellows-shaped flexible pipes, but the air supply pipe (3) is made of aluminum and has an exhaust pipe ( 4) Stainless steel, cover tube (5)
Has a configuration in which ceramic fibers are hardened with an adhesive material such as cement paste. The cover tube (5) may be made of glass or carbon as long as it is a material having a high heat insulating property. Further, the exhaust pipe (4) may be made of a material having a high corrosion resistance because the drain may adhere to the inner surface thereof.

As shown in FIG. 2, an exhaust pipe (4) is inserted into the air supply pipe (3), and this exhaust pipe (4)
A cover tube (5) is covered so as to form an air space therebetween. An air supply passage (30) is formed between the cover pipe (5) and the air supply pipe (3). In addition, the cover tube
(5) is covered on the exhaust pipe (4) in the direction in which the exhaust pipe (4) extends from the upper exhaust outlet (111).

In this device, the air supply pipe (3) has an inner diameter of 100
mm, outer diameter 110mm, exhaust pipe (4), inner diameter 60mm,
Outer diameter 63mm, cover tube (5) has inner diameter 65mm, outer diameter 7
It is set to 0 mm. When connecting the intake pipe (3) and the exhaust pipe (4) to the casing (10) and the combustor (1a), as shown in FIGS. 4 and 5, the exhaust pipe (4) was It is inserted into the cylindrical body (100) and through the opening (101) and externally connected to the upper exhaust outlet (111), and the entire exhaust pipe (4) is covered with a cover pipe (5). After this, the air supply pipe is connected to the cover pipe (5).
Cover (3) and externally connect the air supply pipe (3) to the cylinder (100).
A fixing band (not shown) or the like is used to fix the air supply pipe (3) to the cylinder (100) and fix the exhaust pipe (4) to the upper exhaust outlet (111).

In this apparatus, as shown in FIG. 2, the air supply pipe (3) is connected to the air supply cylinder (7a) inserted through the wall hole (81), and the exhaust pipe (4) is connected to the air supply cylinder. (7a) is connected to the exhaust pipe (7b) inserted and fixed inside. The air supply cylinder (7a) is fixed to the wall (8) via a cylindrical holder (70) closely fitted into the wall hole (81), and the air supply cylinder (7a) and the exhaust cylinder ( 7b) are connected so as to form an air supply passage all around between them.

* Lid (2) * As shown in FIG. 5, this water heater has the above-mentioned opening (10).
2) and a lid (2) that is detachably attached across the rear exhaust outlet (112). This lid (2)
Cover plate (21), and a tubular portion (2) projecting from the back surface of the cover plate (21) and externally fitting to the rear exhaust outlet (112).
2).

The cover plate (21) and the cylindrical portion (22) are formed by pressing stainless steel, and are caulked to each other. In addition, the cover plate (21) is
0b), and a packing (not shown) is interposed between them. Therefore, the opening (102)
Are airtightly closed. Further, the O-ring (23) mounted on the inner peripheral portion of the cylindrical portion (22) ensures airtightness between the cylindrical portion (22) and the rear exhaust outlet (112).

[Use of this water heater] In this water heater, when the air supply fan (11) in the casing (10) is operated, the air supply pipe (3) connected to the cylinder (100) and the air supply pipe (3) connected thereto are connected. The supply air is guided from outside into the casing (10) through the supplied air supply cylinder (7a). The air supply in the casing (10) is supplied into the burner box (13) by the air supply fan (11), and is used for gas combustion in the burner (12). The combustion gas (exhaust) generated by this combustion is transferred to the peripheral wall of the heat exchanger (14).
(14a) When passing through the inside, heat exchange occurs with water in the water pipe, whereby the water in the water pipe is heated to hot water. This hot water
Used and supplied to baths and toilets.

Further, the combustion gas after the heat exchange (exhaust gas)
Collects in the forked pipe (17) via the lid (16), and then passes through the exhaust pipe (4) connected to the upper exhaust outlet (111) and the exhaust pipe (7b) connected to this. Led outside. In this apparatus, there is a cover pipe (5) which is placed over the exhaust pipe (4) to form an air supply passage (30) between the exhaust pipe (4) and the air supply pipe (3).
An air layer is formed over the entire circumference between (5) and the exhaust pipe (4). Therefore, the heat insulating effect of the air layer, and
The heat exchange between the exhaust gas in the exhaust pipe (4) and the air supply in the air supply passage (30) is suppressed by the heat insulating action of the cover tube itself. Thereby, the casing into which the air supply is sucked
The temperature rise in (10) is suppressed.

Therefore, the air supply pipe (3) and the exhaust pipe (4) are relatively long (for example, 3 mm) in relation to the installation location of the water heater.
m), the electrical component (18) and the like in the casing (10) are not overheated, and the failure of the water heater is prevented. Also, exhaust pipe
Since the heat exchange between the exhaust gas in (4) and the air supply in the air supply passage (30) is suppressed, the cooling of the exhaust gas in the exhaust pipe (4) is suppressed,
As a result, the generation and adhesion of drain on the inner surface of the exhaust pipe (4) is suppressed. Therefore, corrosion of the exhaust pipe (4) by the drain is suppressed.

In this case, the casing (10) has the above-described airtight structure, and since indoor air does not flow into the casing (10), the casing (10) is
There is no cooling action in (10). Therefore, the above cover tube
The necessity of the effect of suppressing the temperature rise in the casing (10) by (5) becomes particularly remarkable. Further, since the casing (10) has the above-mentioned airtight structure, even if the casing (10) is installed in a place such as a bathroom that is easily wetted by water, the casing (10)
No water or water vapor enters. Therefore, also in this respect, the failure of the water heater is prevented.

In this case, since the cover tube (5) has a bellows shape, the surface area is larger than that of a straight tube, and the heat insulating area of the cover tube (5) itself is larger. Therefore, also at this point, the heat exchange is suppressed, and the temperature rise in the casing (10) is suppressed. In this case, the air supply pipe (3) is
00), and the exhaust pipe (4) is connected to the upper exhaust outlet (111) located in the casing (10).
Of the casing (10) without being covered by the air supply pipe (3)
In this state, heat is directly conducted from the most upstream portion of the exhaust pipe (4) into the casing (10).

However, the exhaust pipe (111)
The exhaust pipe (4) is covered with a cover pipe (5) over the direction in which (4) extends, and the uppermost stream of the exhaust pipe (4) is covered with the cover pipe.
(5), the heat conduction from the uppermost stream portion into the casing (10) is suppressed by the heat insulating effect of the air between them and the heat insulating effect of the cover tube (5) itself. . Therefore, also in this point, the temperature rise in the casing (10) is suppressed.

In this case, since the air supply pipe (3), the exhaust pipe (4) and the cover pipe (5) are each a bellows-shaped flexible pipe, these air supply pipe (3), exhaust pipe (4) and cover The pipe (5) can be bent to accommodate various installation locations.
In this case, when installing the air supply pipe (3) and the exhaust pipe (4), the above heat insulation structure is achieved simply by covering the exhaust pipe (4) with the cover pipe (5). The installation work is more efficient than applying or winding.

The cover pipe (5) has a structure in which an air layer is formed over the entire circumference between the cover pipe (5) and the exhaust pipe (4).
Since the cover (5) can be covered with a margin, the work of covering the exhaust pipe (4) with the cover pipe (5) is simple. Therefore, also in this respect, the installation work becomes efficient. Further, since the exhaust pipe (4) and the cover pipe (5) are each bellows, when the exhaust pipe (4) and the cover pipe (5) having different diameters come into contact with each other, the cover pipe (5) Exhaust pipe is the minimum diameter of
(4) is in point contact with the outer peripheral surface, and the air layer is reliably formed between the two. Therefore, the exhaust pipe (4)
(5) The air layer is formed over almost the entire periphery just by covering the air layer.

Further, the exhaust pipe (4) and the cover pipe (5) have a configuration in which the pitches of the peaks are different. For example, the pitch of the peak of the exhaust pipe (4) is about 1.5 mm,
The pitch of the peaks in (5) is about 1 mm. Therefore, the ridges of the exhaust pipe (4) and the cover pipe (5) do not overlap and come into close contact with each other. In this respect, an air layer is reliably formed between the two. Further, since the close contact is prevented, the work of inserting the exhaust pipe (4) into the cover pipe (5) becomes easy.

[Regarding change to rear air supply / exhaust type] In this water heater, as described above, the cylindrical body (100) and the upper exhaust outlet
Although an air supply pipe (3) and an exhaust pipe (4) are connected to (111), an upper air supply / exhaust type as shown in FIG. 5 can be used, but this can be changed to a rear air supply / exhaust type. For this change, the cylinder (100)
Without connecting the air supply pipe (3) and the exhaust pipe (4) to the upper exhaust outlet (111), the cylinder (1) is inserted through the projecting plate (10c) of the casing (10).
00) and the opening (102) and the rear exhaust outlet (1
Remove lid (2) from 12).

In this device, an opening (101) and an upper exhaust outlet are provided.
The relative positional relationship between the opening (102) and the opening (102) and the rear exhaust outlet (112) are set to be the same, and as a result, as shown in FIG. (2) Open
(101) and upper exhaust outlet (111). At this time, the cover plate (21) is attached to the protruding plate (10c) so that the opening (101) is closed by the cover plate (21) and the cylindrical portion (22) is fitted to the upper exhaust outlet (111). Screw. In this protruding plate (10c), the screw hole for the lid (2) and the screw hole for the cylinder (100) are shared.

An air supply pipe (not shown) extending outside is connected to the opening (102), and a rear exhaust outlet is provided.
An exhaust pipe (not shown) extending outside is connected to (112). As a result, the supply air is guided from the outside into the casing (10), and the exhaust is guided from the rear exhaust outlet (112) to the outside. Therefore, in this device, the upper supply / exhaust type and the rear supply / exhaust type can be easily switched, and the upper supply / exhaust water heater and the rear supply / exhaust water heater can be shared. [Other embodiments]. In the above embodiment, the air supply pipe (3) and the exhaust pipe (4)
Are connected to the supply cylinder (7a) and the exhaust pipe (7b) through the wall hole (81).
Instead of using (7b), the air supply pipe (3) and the exhaust pipe (4) may be directly inserted into the wall hole (81).

[0049] In the above embodiment, the exhaust pipe (4) is covered with the cover pipe (5) in the direction in which the exhaust pipe (4) extends. A configuration in which a cover pipe (5) is put on a part of the exhaust pipe (4) may be adopted. . In the above-described embodiment, the air supply pipe (3), the exhaust pipe (4), and the cover pipe (5) are all bellows-shaped flexible pipes. Alternatively, it may not be a flexible tube. If the exhaust pipe (4) and the cover pipe (5) are not formed in a bellows shape, the exhaust pipe (4) and the cover pipe are installed so that an air layer is formed around them all around. .

[0050] In the above embodiment, the casing (1
The upper exhaust outlet (111) of the combustor (1a) is located more inward than the opening (101) of the opening (101).
The upper exhaust outlet (111) may be configured to protrude further outward. . In the above-described embodiment, the air supply fan (11) for pushing air supply toward the burner (12) is used in order to make the combustor (1a) a forced supply / exhaust type. ) May be configured to use an exhaust fan that sucks the exhaust gas generated in the above. In this case, a configuration in which an exhaust fan is mounted between the lid (16) and the forked pipe (17) can be adopted.

[0051] In the above embodiment, the combustion device described above is a water heater, but as long as the combustion device accommodates a forced air supply type combustor in a casing installed indoors,
For example, it may be a heating device.

[Brief description of the drawings]

FIG. 1 is a front view of a water heater according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the water heater of FIG. 1 taken along the line II-II.

3 is a front view of the water heater of FIG. 1 with a cover (10a) of a casing (10) removed.

FIG. 4 is an explanatory view of assembling an air supply pipe (3), an exhaust pipe (4) and a cover pipe (5) of the water heater of FIG.

FIG. 5 is an enlarged cross-sectional view of the casing (10) and the upper end of the combustor (1a) in the water heater of FIG. 2;

FIG. 6 is an enlarged cross-sectional view of the casing (10) and the upper end of the combustor (1a) when the water heater of FIG. 5 is a rear exhaust type.

FIG. 7 is a diagram showing an outline of the configuration of a conventional water heater (9).

[Explanation of symbols]

 (10) ・ ・ ・ Casing (1a) ・ ・ ・ Combustor (3) ・ ・ ・ Air supply pipe (4) ・ ・ ・ Exhaust pipe (5) ・ ・ ・ Cover pipe

Claims (5)

[Claims] 1. A combustion apparatus in which a forced supply / exhaust type combustor is housed in a casing installed indoors, comprising: an air supply pipe connected to the casing and for introducing air supply into the casing from outside; An exhaust pipe inserted into the air supply pipe, connected to the combustor, and for guiding exhaust gas from inside the combustor to the outside, wherein an air layer is formed between the exhaust pipe and the exhaust pipe. And a cover pipe that covers the exhaust pipe and forms the air supply passage between the exhaust pipe and the air supply pipe. 2. The combustion apparatus according to claim 1, wherein the air supply pipe, the exhaust pipe, and the cover pipe are each a bellows-shaped flexible pipe. 3. The combustion device according to claim 1, wherein a portion of the casing other than a connection portion with the air supply pipe is airtight. 4. The air supply pipe is connected to an air supply opening formed in the casing, the exhaust pipe is connected to an exhaust outlet of the combustor located in the casing, and the cover pipe is The combustion apparatus according to any one of claims 1 to 3, wherein the exhaust pipe is covered from the exhaust outlet in a direction in which the exhaust pipe extends. 5. The casing is a wall-mounted type, wherein the combustor includes an air supply fan, a burner box connected to an upper end of the air supply fan and containing a burner, and an upper end of the burner box. A hot water supply heat exchanger connected in series, and an exhaust gas consolidation section connected to the upper end of the hot water supply heat exchanger and having the exhaust outlet, wherein the air supply port is an upper surface plate of the casing. The exhaust outlet is formed at a position facing the air supply port in the exhaust gas collecting section, and the air supply pipe is detachably connected to the air supply port, and the exhaust pipe Is detachably connected to the exhaust outlet, and has a second air supply port formed in the back plate of the casing, and a position facing the second air supply port in the exhaust gas collecting part. A second exhaust outlet formed in the second exhaust port, the second air supply port, and the second exhaust port. A lid detachably attached to an outlet, wherein the lid is detached from the second air supply port and the second exhaust outlet, and the air supply pipe and the exhaust pipe are provided. The combustion device according to any one of claims 1 to 4, wherein the combustion device is configured to be removably attached to the air supply opening and the exhaust outlet from which the air supply has been removed.