JP2000304352A - Combustion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve sufficient performance, secure high durability and reliability and realize miniaturization of equipment by reducing size of a heat exchanger and at the same time suppressing the boiling of fluid in a pipe that is not used when only one function is used in a combustion device with a plurality of functions such as hot water supply, bath, and heating with a single can. SOLUTION: A junction channel 8 where two channels out of first, second, and third channels 5, 6, and 7 through a heat transfer fin 4 are joined each other, a first double-purpose burner 1E, and a second double-purpose burner 1D are heated for reducing the size of a heat exchanger and drastically miniaturizing equipment, at the same time pipes in the channel are connected for increasing the amount of heat transfer, thus suppressing temperature increase in water in the other residence pipe even if an operation for heating each channel individually is made, preventing the scale in a pipe from being produced, and extending the life of the heat exchanger. More specifically, performance that the device has can be fully exhibited, the durability of the combustion device is improved, and product reliability is drastically improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water heater having a heating function and a reheating function for a bath, and relates to a combustion apparatus having a single combustion heat source and satisfying a plurality of functions.

[0002]

2. Description of the Related Art Conventionally, a combustion device capable of simultaneously heating a plurality of flow paths by one combustion heat source has been employed in a combined hot water supply device such as a hot water supply / heating / bath device capable of operating hot water supply, heating and bath operation. A conventional combustion apparatus of this type is disclosed in Japanese Patent Application Laid-Open No. 9-24.
There was one described in Japanese Patent No. 3166.
In this combustion device, as shown in FIG.
And a hot water supply burner 1A, a bath burner 1B, a heating burner 1C, a blower fan 2 for supplying air to the burner 1, and a gas proportional valve 3 for supplying fuel to the burner unit 1.
And a plurality of heat transfer fins 4, a hot water supply pipe 5 penetrating through the heat transfer fins 4 and heated by the burner 1, a bath pipe 6, and a heating pipe 7. The hot water supply pipe 5, the bath pipe 6, and the heating pipe 7 are arranged in parallel to each other, and have a joining flow path 8 in which round pipes are joined to each other. At this time, hot water supply burner 1A heats hot water supply pipe 5, bath burner 1B heats bath pipe 6, and heating burner 1C heats heating pipe 7.

[0003]

However, in the configuration of the conventional combustion apparatus, the hot water supply burner 1A, the bath burner 1B, and the heating burner 1C are completely independent of each other in the burner unit 1. In addition, since the joining flow path 8 joined by the round pipes is always heated when the hot water supply alone operation is performed, the water temperature in the other non-operating bath pipe 6 and the heating pipe 7 is reduced. Will rise. That is, if the joining flow path 8 is simply a joining of circular pipes and the contact area between the pipes is small and the amount of heat transfer is insufficient, when the hot water supply operation is performed, the joining flow rate exceeds The amount of heat received by the bath pipe 6 or the heating pipe 7 of the road 8 increases, and the water temperature in the bath pipe 6 or the heating pipe 7 rises, sometimes leading to boiling. When the water in the pipe boils, scale adheres to the pipe and the flow path is blocked, so that there is a possibility that the operation cannot be performed. Also, when the bath or the heating is operated alone, the joining flow path 8 is constantly heated, so that when the combustion amount exceeds a predetermined amount, the amount of heat received by the hot water supply pipe 5 increases, and the hot water supply pipe 5
In some cases, the temperature of the water inside the building increased and it became hot. for that reason,
There were problems with high-temperature hot water supply due to an increase in the initial water temperature at the start of hot water supply operation, and durability and reliability of the heat exchanger.

[0004]

According to the present invention, in order to solve the above-mentioned problems, a burner unit is provided with a group of common burners for simultaneously heating a plurality of flow paths, and a power supply heated by a high-temperature gas generated by the burner unit. The heat fin has a common heat transfer fin provided with a plurality of flow passages heated by the common burner group, and has a plurality of flow passages penetrating the common heat transfer fin and provided in parallel with the burner unit. Is composed of a first flow path, a second flow path, and a third flow path, and two flow paths of the first flow path, the second flow path, or the third flow path are joined to each other through the common heat transfer fin. Is a combustion device having a heat exchange device having a joined flow path.

According to the above-mentioned invention, in a combustion apparatus having a plurality of functions such as hot water supply, bathing, and heating in one can body, the heat exchanger can be reduced in size, so that the equipment can be downsized. When only the function is used, the boiling of the fluid in the pipe that is not used can be suppressed, so that sufficient performance can be exhibited and high durability performance and reliability performance can be secured.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention provides a burner unit having a plurality of common burners for heating a plurality of flow paths simultaneously,
A shared heat transfer fin provided with a plurality of flow passages heated by the shared burner group, a first flow passage and a second flow passage which penetrate the heat transfer fin and constitute a plurality of flow passages provided in parallel with the burner unit. A flow path and a third flow path are provided, and the flow path penetrating the shared heat transfer fin constitutes a bonded flow path in which two flow paths of the first flow path, the second flow path, or the third flow path are bonded to each other. Things.

[0007] The common heat transfer fins are heated by heating the common heat transfer fins, and the shared heat transfer fins are joined to each other by joining two of the first, second, and third passages. A large size reduction of the equipment can be realized by having a configuration that penetrates, and even if the operation of heating each flow path independently is performed by joining the tubes and increasing the amount of heat transfer,
It is possible to suppress a rise in the temperature of the water in the other remaining pipe, prevent the generation of scale in the pipe, and prolong the life of the heat exchanger.

The burner unit includes a common burner group and a first burner group. The common burner group heats a second flow path and a third flow path which are bonding flow paths penetrating the common heat transfer fins. The first burner group mainly heats the first flow path that passes through the first dedicated heat transfer fin dedicated to the first burner group provided in the heat transfer fin.

By heating the first flow path penetrating the first dedicated heat transfer fin, the first flow path is provided with a dedicated fin. Can be satisfied, and the size of the device can be reduced.

The burner unit includes a common burner group, a first burner group, and a second burner group, and the common burner group includes a first flow path, a second flow path, or a third flow path penetrating the common heat transfer fin. The first burner group heats the first flow path penetrating the first dedicated heat transfer fin provided in the heat transfer fins, and the second burner group heats the joint flow path joining the two flow paths. The second flow path passing through the second heat transfer fin provided on the heat fin is heated.

By providing dedicated fins in the first flow path and the second flow path, the first flow path and the second flow path can satisfy the required performance even if a plurality of functions are used simultaneously.
Equipment can be downsized.

Further, the burner unit includes a first shared burner group, a second shared burner group, a first burner group, a second burner group, and a third burner group, wherein the first shared burner group is connected to a first shared heat transfer fin. Heating a joining flow path that joins the two flow paths of the first flow path and the second flow path provided, the second shared burner group is the first flow path and the third flow path provided in the second shared heat transfer fin. Heating the joining flow path where the two flow paths are joined, the first burner group heats the first flow path penetrating the first dedicated heat transfer fin provided in the heat transfer fin, and the second burner group is The second flow path passing through the second dedicated heat transfer fin provided in the heat transfer fin is heated, and the third burner group passes through the third dedicated heat transfer fin provided in the heat transfer fin. This is for heating the flow path.

The first flow path and the second flow path can satisfy the required performance even when a plurality of functions are used simultaneously.
Equipment can be downsized.

[0014]

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

(First Embodiment) A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a configuration diagram of a heat exchanger and a burner unit of a combustion device, in which hot water supply, heating, and a bath are simultaneously operated. FIG. 2 is a schematic diagram of a whole in which the combustion device is incorporated in a hot water supply / heating bath device. It is. In the figure, 1
Is a plurality of burner units, and burner unit 1
Is a shared burner group 1D for heating hot water supply and heating water and a common burner group 1 for heating hot water supply and bath water at a boundary indicated by a broken line.
E. A fan 2 for blowing air to the burner unit 1, a gas proportional valve 3 for controlling a gas supply amount to the burner unit 1, a plurality of heat transfer fins 4 heated by a high-temperature gas generated by the burner unit 1, A plurality of solenoid valves 9 for switching between a hot water supply operation, a heating operation and a bath operation and for switching the number of burners of the burner unit 1, and a heat transfer fin 4 intersecting with the flow of the hot gas downstream of the hot gas;
, A hot water supply pipe 5 as a first flow path, a bath pipe 6 as a second flow path, and a heating pipe 7 as a third flow path provided in parallel with the burner unit 1. The hot water supply pipe 5 has a substantially heart-shaped pipe flow path and is brazed to a bath pipe 6 and a heating pipe 7 to form a connection flow path 8. The joint flow path 8 between the hot water supply pipe 5 and the bath pipe 6 is heated by a plurality of common burners 1E, and the hot water supply pipe 5 and the heating pipe 7 are heated by a plurality of common burners 1D. Further, the heating pipe 7 is provided with a heating circulation pump 10 for circulating hot water and a heating terminal device 11. The bath pipe 6 has a bath circulation pump 12 for circulating hot water,
A bathtub 13 is provided.

The problem with the configuration of the conventional example is that the hot water supply burner 1A and the bath burner 1B are completely independent from each other, so that there is a limit to the miniaturization of the equipment body. Further, since the control of the combustion amount is performed only by the gas proportional valve 3, the joining flow path 8 is always heated when performing each independent operation, so that the temperature of the water in the other pipe not operating increases. For example, when a hot water supply operation is performed, if the amount of combustion exceeds a predetermined amount of heat, the amount of heat received by the bath tube 6 increases, and the temperature of the water in the bath tube 6 rises, sometimes leading to boiling. When the water in the bath tube 6 boils, a scale may adhere to the inside of the bath tube 6 and block the bath tube 6, so that there is a possibility that the bath operation cannot be performed. Further, even when the bath is operated alone, the joining flow path 8 is constantly heated, so that the amount of heat received by the hot water supply pipe 5 increases when the combustion amount exceeds a predetermined amount, and the water temperature in the hot water supply pipe 5 rises to a high temperature. There were things. Therefore, there have been problems in hot water supply due to an increase in the initial water temperature at the start of hot water supply operation, and in durability and reliability of the heat exchanger.

As means for solving this problem, a common burner group for simultaneously heating two flow paths is provided in the burner unit 1 as in this embodiment, and the hot water supply pipe 5 and the bath pipe 6 are connected in parallel with the arrangement of each burner. A heating pipe 7 is provided, and a joining flow path 16 that joins the hot water supply pipe 5 and the bath pipe 6 and a joining flow path 16 that joins the hot water supply pipe 5 and the heating pipe 7 are provided. The pipe 5 is provided with a deformed pipe obtained by deforming the pipe 5 into a substantially heart shape.

Therefore, according to the configuration of the embodiment of the present invention shown in FIG. 1, the burner unit 1 is entirely composed of the common burner 1D and the common burner 1E, and the flow path is formed by the joint flow path 8 which can realize two functions. Therefore, the size of the combustion device can be significantly reduced. Further, since the hot water supply pipe 5 in the connection flow path 8 is deformed into a substantially heart shape and is connected to the bath pipe 6 or the heating pipe 7, the connection area becomes large, and the accumulated water inside the pipe whose operation is stopped is reduced. The heat is easily transferred to the other tube, and the temperature rise of the stagnant water can be suppressed. That is, it is possible to suppress the adhesion of scale in the staying pipe and extend the life of the heat exchanger, to improve the durability performance, and to greatly improve the reliability of the product.

Next, according to another configuration of the embodiment of the present invention shown in FIG. 3, the heating pipe 7 and the bath pipe 6 are heated by the common burner 1D, the heating pipe 7 is deformed into a substantially heart shape, and upstream of the flame. It is located on the side. In addition, the hot water supply pipe 5 and the bath pipe 6 are heated by the common burner 1E, and the hot water supply pipe 5 is deformed into a substantially heart shape and arranged on the upstream side of the flame. By adopting the above configuration, simultaneous operation in which priority is given to the hot water supply capacity and the heating capacity can be realized, and the joining area of the joining flow path 8 becomes large, and the heat of the stagnant water in the stopped pipe is reduced to the other. Easily transfer heat to the tube and
The temperature rise of the stagnant water can be suppressed. That is, it is possible to suppress the adhesion of scale in the staying pipe and extend the life of the heat exchanger, to improve the durability performance, and to greatly improve the reliability of the product.

Next, according to another configuration of the embodiment of the present invention shown in FIG. 4, the joining flow path 8 heated by the shared burner 1D is used.
Among them, the heating pipe 7 close to the flame is deformed into a substantially heart shape and joined to the hot water supply pipe 5. Even with such a configuration, it is possible to significantly reduce the size of the device and suppress the adhesion of scale.

In this embodiment, the flow path penetrating the heat transfer fins 4 is described as an example in which the flow path is applied to the hot water supply pipe 5, the bath pipe 6, and the heating pipe 7, but the hot water supply pipe 5 and the two bath pipes 6, or Hot water pipe 5 and two heating pipes 7, bath pipe 6 and two heating pipes 7,
The same effect can be obtained even if the combination is changed and applied like the heating pipe 7 and the two bath pipes 6. Furthermore, although an example is shown in which only one of the hot water supply pipe 5 and the heating pipe 7 in the joining flow path 8 is deformed into a substantially heart shape, a similar effect can be obtained by deforming all the pipes to increase the joining area. Can be demonstrated. Even without using a deformed pipe, the size of the equipment can be reduced and the temperature rise of the stagnant water can be suppressed to some extent.

(Embodiment 2) FIG. 5 shows Embodiment 2 of the present invention, and is a configuration diagram of a heat exchanger and a burner unit of a combustion apparatus according to an embodiment of the present invention, in which simultaneous operation of hot water supply, heating and bath is performed. If you are. The objects and effects of the present invention are the same as those shown in the first embodiment. The difference in the configuration from the present embodiment is that the burner unit 1 is provided with a heating burner 1C which is the first burner group 1A, and is a single tube. Heating pipe 7 is the first dedicated fin 1
4 and a dedicated heating configuration. The components having the same reference numerals as those in the first embodiment have the same structure, and a description thereof will be omitted.

As shown in FIG. 5, the hot water supply pipe 5 is deformed into a substantially heart shape and joined to the bath pipe 6 to form a joining flow path 8 and heated by the shared burner 1E, thereby realizing miniaturization of the equipment for the two functions. it can. Furthermore, by heating the heating pipe 7 with a heating burner, even if the heating operation is performed for the longest operation time, the joint flow path 8 is not heated, so that the durability of the combustion device is improved, and the reliability of the product is greatly improved. To improve.

Next, a first burner group 1A as shown in FIG.
The same effect can be exhibited by using a hot water supply burner as a special configuration and heating the hot water supply pipe 7 exclusively.

Further, in the present embodiment, an example is described in which the flow path penetrating the heat transfer fins 4 is applied to the hot water supply pipe 5, the bath pipe 6, and the heating pipe 7, but the hot water supply pipe 5 and the two bath pipes 6, or Hot water pipe 5 and two heating pipes 7, bath pipe 6 and two heating pipes 7,
The same effect can be exerted even when applied to the heating pipe 7 and the two bath pipes 6. Furthermore, although an example is shown in which only one of the hot water supply pipe 5 and the heating pipe 7 in the joining flow path 8 is deformed into a substantially heart shape, a similar effect can be obtained by deforming all the pipes to increase the joining area. Can be demonstrated. Even without using a deformed pipe, the size of the equipment can be reduced and the temperature rise of the stagnant water can be suppressed to some extent.

(Embodiment 3) FIG. 7 is a configuration diagram of a heat exchanger and a burner unit of a combustion apparatus according to Embodiment 3 of the present invention, in which hot water supply, heating and bath are simultaneously operated. The objects and effects of the present invention are the same as those shown in Embodiment 1,
The difference between this embodiment and the present embodiment is that the burner unit 1 includes a heating burner which is a first burner group 1A and a second burner group 1B.
The first dedicated fin 1 is provided with a hot water supply burner.
The configuration is such that the heating pipe 7 penetrating the four portions and the hot water supply pipe 5 penetrating the second exclusive fin 15 are exclusively heated. The components having the same reference numerals as those in the first embodiment have the same structure, and a description thereof will be omitted.

As shown in FIG. 7, the hot water supply pipe 5 is deformed into a substantially heart shape, and is joined to the bath pipe 6 to form a joining flow path 8 and is heated by the shared burner 1E. it can. Further, when the capacity in the steady heating state is small, the heating pipe 7 is heated by the heating burner which is the third burner group 1C, so that the junction flow path 8 can be heated even in the longest heating operation. As a result, the durability performance of the combustion device is improved, and the reliability of the product is greatly improved. Further, when a small amount of hot water supply output is required by heating a part of the hot water supply pipe 5 with a dedicated hot water supply burner that is the first burner group 1A, the joining flow path 8 can be heated because the hot water supply pipe 5 can be heated only by the hot water supply burner. As a result, the durability performance of the combustion device is improved, and the reliability of the product is greatly improved.

Further, in this embodiment, the example in which the flow path penetrating the heat transfer fins 4 is applied to the hot water supply pipe 5, the bath pipe 6, and the heating pipe 7, but the hot water supply pipe 5 and the two bath pipes 6, or Hot water pipe 5 and two heating pipes 7, bath pipe 6 and two heating pipes 7,
The same effect can be exerted by changing the combination of the heating pipe 7 and the two bath pipes 6 and applying them. Furthermore, although an example is shown in which only one of the hot water supply pipe 5 and the heating pipe 7 in the joining flow path 8 is deformed into a substantially heart shape, a similar effect can be obtained by deforming all the pipes to increase the joining area. Can be demonstrated. Even without using a deformed pipe, the size of the equipment can be reduced and the temperature rise of the stagnant water can be suppressed to some extent.

(Embodiment 4) FIG. 8 shows a fourth embodiment of the present invention, in which a heat exchanger and a burner unit of a combustion apparatus according to the present invention are shown, in which hot water supply, heating and bath are simultaneously operated. It is. The objects and effects of the present invention are the same as those described in the first embodiment. The difference in the configuration from the present embodiment is that the burner unit 1 includes a heating burner as the first burner group 1A and a second burner group 1B. A certain hot water supply burner and a bath burner as the third burner group 1C are provided, and the heat transfer fins 4 pass through the heating pipe 7 and the second dedicated fin 15 that pass through a part of the single dedicated fin 14 that is a single tube. The configuration is such that the bath pipe 6 penetrating the hot water supply pipe 5 and the third exclusive fin 16 is heated exclusively. The components having the same reference numerals as those in the first embodiment have the same structure, and a description thereof will be omitted.

As shown in FIG. 8, the hot water supply pipe 5 is deformed into a substantially heart shape and joined to the bath pipe 6 to form a joining flow path 8, which is heated by the first common burner 1E, and the heating pipe 7 is deformed into a substantially heart shape. By joining with the bath tube 6 to form the joining flow path 8 and heating it with the second shared burner 1D, the miniaturization of the equipment for the two functions can be realized. In addition, when the capacity in the steady heating state is small, the heating pipe 7 is heated by the heating burner of the third burner unit 1C, so that the joining flow path 8 can be heated even when the heating operation is performed for the longest operation time. Since there is no combustion device, the durability performance of the combustion device is improved, and the reliability of the product is greatly improved. Further, when a small amount of hot water supply output is required by heating a part of the hot water supply pipe 5 with the hot water supply burner of the first burner group 1A, the hot water supply pipe 5 can be heated only by the hot water supply burner, so that the joining flow path 8 is not heated. Therefore, the durability performance of the combustion device is improved, and the reliability of the product is significantly improved. Further, the bath pipe 6 can be heated exclusively by the bath burner 1B even when the bath is operated alone.

In this embodiment, the flow path penetrating the heat transfer fins 4 is applied to the hot water supply pipe 5, the bath pipe 6, and the heating pipe 7, but the hot water supply pipe 5 and the two bath pipes 6, or Hot water pipe 5 and two heating pipes 7, bath pipe 6 and two heating pipes 7,
The same effect can be exerted by changing the combination of the heating pipe 7 and the two bath pipes 6 and applying them. Furthermore, although an example is shown in which only one of the hot water supply pipe 5 and the heating pipe 7 in the joining flow path 8 is deformed into a substantially heart shape, a similar effect can be obtained by deforming all the pipes to increase the joining area. Can be demonstrated. Even without using a deformed pipe, the size of the equipment can be reduced and the temperature rise of the stagnant water can be suppressed to some extent.

[0032]

As described above, the following effects can be obtained in the heat exchange apparatus having the configuration as described above.

(1) The burner units are all composed of a common burner group to heat the common heat transfer fins, and the common heat transfer fins are formed by two of the first flow path, the second flow path, and the third flow path. With the configuration in which the joining flow paths joined to each other penetrate, the size of the equipment can be significantly reduced, and the operation of heating each flow path independently by joining the tubes and increasing the amount of heat transfer is realized. Even if it is performed, it is possible to suppress an increase in the temperature of the water in the other remaining pipe, prevent the generation of scale in the pipe, and prolong the life of the heat exchanger. That is, the performance of the device is sufficiently exhibited, the durability of the can body is improved, and the reliability of the product is greatly improved.

(2) A common burner group and a first burner group are provided in the burner unit, and the common burner group heats the second and third flow paths which are the joining flow paths penetrating the common heat transfer fins. One burner group heats the first flow path penetrating the first dedicated heat transfer fin provided in the heat transfer fin, so that the dedicated fin is provided in the first flow path. The required capacity can be satisfied even when used, and the size of the device can be reduced.

(3) A common burner group, a first burner group, and a second burner group are provided in the burner unit, and the common burner group includes a first flow path, a second flow path, or a third flow path penetrating the common heat transfer fins. Heating the joint channel that joined the two channels,
The first burner group heats the first flow path passing through the first heat transfer fin provided on the heat transfer fin, and the second burner group heats the first flow path passing through the second dedicated heat transfer fin provided on the heat transfer fin. By heating the path, the first flow path and the second flow path can satisfy the required capacity even if a plurality of functions are used at the same time by providing dedicated fins in the first flow path and the second flow path. In addition, the size of the device can be reduced.

(4) A first common burner group, a second common burner group, a first burner group, a second burner group, and a third burner group are provided in the burner unit, and the first common burner group is a first common heat transfer fin. Heats the joining flow path in which the two flow paths of the first flow path and the second flow path provided in the first flow path and the second flow path are joined, and the second shared burner group is the first flow path and the third flow path provided in the second shared heat transfer fin. The first burner group heats the first flow path that penetrates the first dedicated heat transfer fin, and the second burner group heats the first flow path that penetrates the second dedicated heat transfer fin. The second flow path is heated, and the third burner group heats the third flow path passing through the third dedicated heat transfer fin, so that the first flow path, the second flow path, and the third flow path simultaneously use a plurality of functions. Even if you can meet the required capacity,
Equipment can be downsized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a combustion device according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram of the entire apparatus.

FIG. 3 is another configuration diagram of the first embodiment of the present invention.

FIG. 4 is another configuration diagram of the first embodiment of the present invention.

FIG. 5 is a configuration diagram of a combustion device according to a second embodiment of the present invention.

FIG. 6 is another configuration diagram of the second embodiment of the present invention.

FIG. 7 is a configuration diagram of a combustion device according to a third embodiment of the present invention.

FIG. 8 is a configuration diagram of a combustion apparatus according to a fourth embodiment of the present invention.

FIG. 9 is an overall view of a conventional combustion device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Burner unit 1A 1st burner group 1B 2nd burner group 1C 3rd burner group 1E 1st common burner 1D 2nd common burner 1F 3rd common burner 4 Heat transfer fin 5 1st flow path (hot water supply pipe) 6 2nd flow path (Bath pipe) 7 Third flow path (heating pipe) 8 Joining flow path 14 First exclusive fin 15 Second exclusive fin 16 Third exclusive fin

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Fumitaka Kikutani 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Kazuya Ariyama 1006 Kadoma Kadoma, Kadoma City Osaka Pref. F-term (for reference) 3L034 BA29 BB03 3L036 AA04

Claims (4)

[Claims] 1. A burner unit provided with a group of common burners for heating a plurality of flow paths at the same time, a shared heat transfer fin provided with a plurality of flow paths heated by the set of common burners, and the shared heat transfer fin. A first flow path, a second flow path, and a third flow path that pass through a fin and constitute a plurality of flow paths provided in parallel with the burner unit; the first flow path or the second flow path or the third flow path; A combustion device comprising a joining channel in which two of the channels are joined to each other. 2. The burner unit includes a common burner group and a first burner group. The common burner group heats a second flow path and a third flow path which are bonding flow paths penetrating the common heat transfer fins. 2. The combustion device according to claim 1, wherein the first burner group mainly heats a first flow path passing through the first dedicated heat transfer fin dedicated to the first burner group provided on the heat transfer fin. 3. 3. The burner unit includes a common burner group, a first burner group, and a second burner group, and the common burner group includes a first flow path, a second flow path, or a third flow path penetrating the common heat transfer fins. Heating the joining flow path where the two flow paths are joined, the first burner group heats the first flow path penetrating the first dedicated heat transfer fin provided in the heat transfer fin, and the second burner group is The combustion device according to claim 1, wherein the second flow path passing through the second exclusive heat transfer fin provided in the heat transfer fin is heated. 4. The burner unit includes a first shared burner group, a second shared burner group, a first burner group, a second burner group, and a third burner group, wherein the first shared burner group is a first shared heat transfer fin. Heats a joining flow path obtained by joining two flow paths of the first flow path and the second flow path provided in the first flow path and the second flow path. The first burner group heats the first flow path penetrating the first dedicated heat transfer fin provided in the heat transfer fin, and heats the joining flow path that joins the two flow paths of the path, and the second burner group Heats the second flow path passing through the second dedicated heat transfer fin provided in the heat transfer fin, and the third burner group passes through the third dedicated heat transfer fin provided in the heat transfer fin. The combustion device according to claim 1, wherein the three flow paths are heated.