JP4674152B2 - Boiler equipment - Google Patents

Description

  In the present invention, a heat transfer pipe is disposed in a combustion gas flow path through which combustion gas of a burner circulates so as to swivel a central axis of the combustion gas flow path, and water supplied into the heat transfer pipe is supplied to the combustion gas flow path. In particular, boilers that generate steam by heating with combustion gas that circulates in the boiler satisfy the demand for a small amount of steam, such as high-temperature superheated steam used for cooking in home or small-scale business applications Relates to the device.

  As described above, as a so-called burner heating type boiler apparatus that generates steam by heating water with burner combustion gas, a small-sized small once-through boiler is known (see, for example, Non-Patent Document 1). .) Such a small once-through boiler described in Non-Patent Document 1 is arranged such that a heat transfer tube as an evaporation tube for evaporating supplied water is swirled in a coil shape (helical shape) in a combustion gas flow path. It is configured to generate saturated steam of Kg / h to several thousand kg / h.

  Recently, it has been equipped with a so-called electric heating boiler device that generates steam by heating water with an electric heater, and using superheated steam generated by the boiler device, cooking not only steamed products but also pottery products etc. Cooking utensils that can be made are commercially available.

"Handbook of Mechanical Engineering B6 Power Plant" The Japan Society of Mechanical Engineers, published in July 1986, p7

However, the electric heating boiler device used in cooking utensils has a problem that the preparation time required from the start of operation to the generation of superheated steam is relatively long, about 10 minutes, due to the limitation of electric capacity.
Therefore, in such a cooking utensil, if a burner heating type boiler device is used, the preparation time can be shortened, and steam is generated immediately when necessary in other applications such as cleaning and sterilization. It is thought that it can also be comprised. However, conventional small once-through boilers have an excessive capacity for use in homes or small-scale businesses (restaurants, etc.) where cooking utensils are installed, and many of them have a structure where superheated steam can be obtained. is not.
That is, in the small once-through boiler, in order to satisfy a small amount of steam demand such as high-temperature superheated steam used for cooking, when the diameter of the heat transfer tube is reduced, steam supply is not possible due to the pulsation of steam generation. The problem of stabilization occurs, and further, the heat transfer tube burns out due to the drift of water (or steam) in the heat transfer tube, and the performance stability decreases due to the non-uniform flow of combustion gas in the combustion gas flow path. The problem is concerned.

  The present invention has been made in view of the above problems, and an object of the present invention is to supply a small amount of steam, particularly superheated steam, stably and efficiently, and water (or steam) in the heat transfer tube. This is to realize a burner heating type boiler apparatus capable of suppressing the uneven flow and the non-uniform flow of the combustion gas in the combustion gas flow path with a small and rational configuration.

In order to achieve the above object, a boiler apparatus according to the present invention includes a heat transfer tube disposed in a combustion gas flow path through which a combustion gas of a burner circulates so as to swivel a central axis of the combustion gas flow path. The water supplied in the pipe is heated by the combustion gas flowing through the combustion gas flow path to generate steam,
The combustion gas flow path is divided into an upstream passage provided with the burner on an axial center, and a downstream passage communicating with the upstream passage,
A shaft passage that is smaller in diameter than the upstream passage and the downstream passage and flows along the outer wall of the upstream passage flows into the downstream passage along the central axis. Protruding toward the burner in the passage,
In the downstream passage, an evaporation pipe for evaporating the supplied water is arranged as the heat transfer pipe,
In the shaft passage, a superheat pipe that superheats the steam supplied from the evaporation pipe is arranged as the heat transfer pipe,
The evaporator tube is in a point that is coaxially arranged with the superheater tube at a location different from the superheater tube from the central axis.

  According to the boiler apparatus, the heat transfer tube swirls in a state where the central axis of the combustion gas flow path is spiral (also referred to as a spiral), helical (also referred to as a string or coil), or a combination thereof. Is arranged in the combustion gas flow path. Therefore, even if the diameter of the heat transfer tube is reduced (for example, about 4 mm) in order to satisfy a small steam demand (for example, 3 kg / h), the heat transfer area of the heat transfer tube is sufficiently secured while ensuring a sufficient heat transfer area. It is possible to realize a rational configuration with as few junctions as possible, and further to suppress the heat transfer tube from burning due to the drift of water (or steam) in the heat transfer tube.

And according to said 1st characteristic structure, while dividing said combustion gas flow path into the upstream part channel | path which provided the said burner on the axial center, and the downstream part channel | path connected to the said upstream part channel | path, the said upstream part A shaft passage having a smaller diameter than the passage and the downstream passage and flowing along the outer wall of the upstream passage flows into the downstream passage along the central axis into the upstream passage. The combustion gas that has flowed into the upstream passage flows mainly along the central axis while turning, but a part of the combustion gas that flows along the outer wall of the upstream passage. However, it circulates in a form in which it collides with a section of the shaft passage and is drawn toward the central shaft.
Furthermore, a part of the combustion gas circulates well in a form attracted to the central axis side by the negative pressure generated near the central axis X by the swirling of the combustion gas and the cylindrical protrusion, and along the central axis The unburned air-fuel mixture that circulates in this way is slowly burned by the mixing of the burned combustion gas that circulates in this manner, and the generation of NOx is suppressed.
Also, an evaporation pipe for evaporating the supplied water is arranged as the heat transfer pipe in the downstream passage, and an overheat pipe for heating the steam supplied from the evaporation pipe is arranged as the heat transfer pipe in the shaft passage. in Rukoto is, by equalizing the pressure loss of the combustion gas in the combustion gas flow passage, the flow of combustion gas in the combustion gas passage and made uniform, it is possible to secure stable performance. Furthermore, since a relatively long heat transfer tube can be disposed in a relatively small combustion gas flow path, for example, each heat transfer tube disposed at a plurality of sites can be nested, so that downsizing is realized. be able to.

In addition to the above characteristic configuration , the second characteristic configuration of the boiler device according to the present invention is :
An annular steam drum that separates water from the steam supplied from the evaporation pipe and supplies the steam to the superheat pipe is disposed in the combustion gas flow path.

According to the first characteristic configuration, the high-temperature combustion gas generated by the burner and flowing into the shaft passage passes through the shaft passage at a relatively high speed along the central axis. High-temperature heat suitable for superheating steam to a high temperature can be satisfactorily transmitted to the superheated tube that is the arranged heat transfer tube. Furthermore, since the combustion gas after the temperature flowing into the downstream passage from the shaft passage is slightly lowered flows through the downstream passage at a relatively low speed, the heat transfer tube disposed in the downstream passage is used. A certain amount of heat sufficient to evaporate water can be satisfactorily transmitted to a certain evaporation pipe.
According to the second characteristic configuration in addition to the above configuration, when the combustion gas flow path is configured to expand from the shaft section passage toward the downstream section passage, the steam supplied from the evaporation pipe to the superheat pipe is used. By disposing an annular steam drum for separating water in the combustion gas flow path, the outer wall of the steam drum can also contribute as a heat receiving surface from the combustion gas to improve thermal efficiency. The increase in size due to the installation of the drum can be suppressed.

Further, by composing the combustion gas flow path so as to reduce the diameter from the upstream passage toward the shaft passage, the combustion generated by the burner disposed on the central axis at the upstream end of the upstream passage. A part of the gas flows along the outer wall of the upstream passage, and then flows in a form in which it collides with the stepped portion to the shaft passage and is drawn toward the central axis. Therefore, the unburned gas mixture flowing along the central axis is mixed with the burned combustion gas drawn toward the central axis as described above, so that the low oxygen concentration state (inactive by nitrogen and carbon dioxide) Combusting slowly without forming a local high temperature portion in a high gas concentration state), thereby suppressing the generation of NOx.

A third characteristic configuration of the boiler device according to the present invention is that, in addition to the above-described characteristic configuration, a cylindrical projecting portion that projects from the outer wall side of the shaft passage to the upstream passage side is formed.

According to the third characteristic configuration, the combustion gas that has flowed along the outer wall of the upstream passage and then collided with the stepped portion to the shaft passage and has been drawn to the central axis side further flows to the outer surface of the cylindrical protrusion. Therefore, the burner is well circulated in the form of being drawn toward the upstream side where the burner is disposed, so that the burned combustion gas can be sufficiently mixed with the unburned mixture to further suppress the generation of NOx. .

A fourth characteristic configuration of the boiler apparatus according to the present invention is that, in addition to the above-described characteristic configuration, the burner is configured to swirl the combustion gas around the central axis.

According to the fourth feature, the burner is configured to swirl the combustion gas around the central axis, so that a negative pressure is generated by the swirling of the combustion gas near the burner on the central axis, A part of the combustion gas circulates in a form attracted to the central axis side by the negative pressure. Therefore, the unburned gas mixture flowing along the central axis slowly forms a local high-temperature part in a low oxygen concentration state by mixing the burned combustion gas drawn toward the central axis as described above. It burns without doing, and it can control generation of NOx by this.

A fifth characteristic configuration of the boiler apparatus according to the present invention is formed such that, in addition to the above-described characteristic configuration, the heat transfer tubes constituting the superheater tube rotate in a helical shape while being in close contact with each other in the direction along the central axis. It is in the point.

According to the fifth characteristic configuration, a cylindrical surface along the outer wall of the combustion gas flow path can be formed by the heat transfer tube swirling as described above around the central axis of the combustion gas flow path. In particular, it is possible to prevent the outer wall of the combustion gas flow path from becoming excessively high on the upstream side where the high-temperature combustion gas flows. Therefore, a general metal material such as stainless steel can be used without using a brittle and high-weight ceramic refractory material unsuitable for conveyance or a metal heat-resistant material such as a nickel-based alloy that is expensive and difficult to process. Can be used to configure the outer wall of the combustion gas flow path, while the heat transfer tube is also cooled by water or steam flowing through it, so that it is not burned out without using a particularly high-grade heat-resistant material. Can be suppressed.
Naturally, since this heat transfer tube also acts as a heat transfer tube that receives heat from the combustion gas, the heat transfer area is effectively secured by forming the heat transfer tubes so as to be in close contact with each other in the direction along the central axis. be able to.

The sixth characteristic configuration of the boiler apparatus according to the present invention is such that, in addition to the above-described characteristic configuration, the outer wall of the combustion gas passage has an air cooling structure, and air after cooling the outer wall is supplied as combustion air for the burner. It is in the point which is comprised.

According to the sixth characteristic configuration, the outer wall of the combustion gas passage is not a heat insulating structure that causes an increase in size and weight, but an air cooling structure, thereby achieving a reduction in size and weight, as well as stainless steel. The outer wall of the combustion gas flow path can be configured using a general metal material such as steel.
Furthermore, the air used for cooling the outer wall of the combustion gas channel can be used as combustion air for the burner, and the heat released through the outer wall of the combustion gas channel can be recovered and circulated without waste. it can. Further, in the burner, the fuel is burned with preheated combustion air, which can improve the combustibility of the fuel and reduce NOx by lean combustion.

Embodiments of the present invention will be described with reference to the drawings.
The boiler apparatus 50 shown in FIGS. 1-3 is arrange | positioned in the combustion gas flow path 10 with which the combustion gas G of the burner 2 distribute | circulates the heat exchanger tube 11 with the form swirling the central axis X of the said combustion gas flow path 10, The It is configured as a burner heating type boiler device that generates steam S by heating the water W supplied into the heat transfer tube 11 with the combustion gas G flowing through the combustion gas passage 10.
Further, the boiler device 50 is characterized in that the heat transfer tubes 11 are swung around the same central axis X over a plurality of portions whose distances from the central axis X are different from each other, that is, coaxially arranged. Steam, particularly superheated steam S, is supplied stably and efficiently, and also suppresses the uneven flow of water W (or steam S) in the heat transfer tube 11 and the non-uniform flow of the combustion gas G in the combustion gas passage 10. It is configured to be able to.
Hereinafter, the detailed structure of the boiler apparatuses 51, 52, and 53 of the first to third embodiments configured as the boiler apparatus 50 will be described.

[First embodiment]
A boiler apparatus 51 of the first embodiment shown in FIG. 1 includes a main body casing 1 made of a cylindrical body sealed at both ends, and the burner 2, the combustion gas flow path 10, the heat transfer tube 11, and the like described above are included therein. Has been placed.
The combustion gas flow path 10 is formed inside the main casing 1 as a flow path having a circular flow path cross-sectional shape centering on the central axis X that is the cylindrical axis.

  Further, the combustion gas passage 10 has a shaft portion passage 10b through which the combustion gas G flows along the central axis X, and is located downstream of the shaft portion passage 10b and has a larger diameter than the shaft portion passage 10b. Downstream portion passage 10c and an upstream portion passage 10a that is located upstream of the shaft portion passage 10b and has a larger diameter than the shaft portion passage 10b.

Specifically, a furnace wall member 5 is provided on the upstream side in the main body casing 1 so as to have a cylindrical shape centered on the central axis X and to be reduced in diameter toward the downstream side. The passage 10 a is formed as a space inside the furnace wall member 5.
Then, between the outer surface of the furnace wall member 5 and the inner surface of the main casing 1, the combustion air A that flows from the air fan 20 through the combustion air port 22 formed in the outer wall of the main casing 1 is transferred to the furnace wall. An air flow path 23 that leads to the opening 5 a on the upstream side of 5 is formed. As will be described in detail later, the burner 2 uses the combustion air A that flows through the combustion air 23 to supply the fuel F. Combustion gas G flows into the upstream passage 10a through the opening 5a.
Further, the combustion air A flows from the opening 5 a into the air flow path 23 in the direction of turning the central axis X, and is supplied to the burner 2 while turning along the outer peripheral surface of the furnace wall member 5. . Therefore, the furnace wall member 5 has a so-called air cooling structure that is cooled by the combustion air A, and the combustion air A preheated by cooling the furnace wall member 5 is supplied to the burner 2.
And this burner 2 is comprised so that the fuel F may carry out the lean combustion with little generation | occurrence | production of NOx using the combustion air A preheated by cooling the furnace wall member 5 in the air flow path 23, Furthermore, the swirler 4 is arranged in the opening 5a on the upstream side of the furnace wall member 5, and the combustion gas G flowing into the upstream passage 10a through the opening 5a is swirled around the central axis X by the swirler 4. It is configured as follows.

Further, a disc-shaped partition member 7 joined to the downstream end of the furnace wall member 5 is provided at a substantially central portion in the main body casing 1, and the downstream passage 10 c is located upstream of the partition member 7. It is formed as a side space. An exhaust port 15 through which the combustion gas G after flowing through the downstream portion passage 10c flows out as exhaust gas is formed outside the downstream portion passage 10c.
And the combustion gas G which flowed out from the exhaust port 15 is guide | induced to predetermined places, such as a ventilation part, through the flue 16 formed of the duct 17 as waste gas, and is discharged | emitted.

  Further, a substantially cylindrical portion 6 in the main body casing 1 is provided with a cylindrical protrusion 6 that protrudes from the edge of the inner opening of the partition member 7 toward the upstream passage 10a. It is formed as a space inside the protrusion 6.

  The burner 2 is disposed on the central axis X on the upstream side of the combustion gas flow path 10, that is, on the upstream side of the upstream passage 10 a, and specifically, is formed on the upstream side of the furnace wall member 5 in the air flow path 23. A plurality of jets formed on the inner surface of the fuel F such as natural gas city gas, etc. formed at equal intervals in the circumferential direction. Combustion is performed using the combustion air A that is blown inward from the hole 2a and supplied through the air passage 23.

With the configuration as described above, the combustion gas G that has flowed into the upstream passage 10a from the opening 5a flows mainly along the central axis X while turning, but the combustion gas that flows along the outer wall of the upstream passage 10a. A part of the gas G circulates in a form in which it collides with the partition member 7 which is a step portion to the shaft passage 10b and is drawn toward the central axis X side.
Furthermore, a part of the combustion gas G circulates well in a form that is attracted to the central axis X side by the negative pressure generated in the vicinity of the central axis X by the swirling of the combustion gas G and the cylindrical protrusion 6, The unburned mixture flowing along the central axis X is slowly burned by the mixing of the burned combustion gas G that circulates in this way, and the generation of NOx is suppressed.

On the other hand, the secondary fuel nozzle 3 is disposed in the opening 5a of the furnace wall member 5 so as to extend toward the upstream side, and the secondary fuel nozzle 3 has the fuel F supplied therein. Are blown out radially from a plurality of nozzle holes 3a formed on the outer surface at equal intervals in the circumferential direction, and burned using the combustion air A flowing into the upstream passage 10a from the opening 5a. ing.
And supply of the fuel F to this secondary fuel nozzle 3 so that the general air ratio in the combustion gas flow path 10 may be maintained in an appropriate range (for example, about 1.1 to 1.6) in which energy saving operation is possible. The amount is controlled.
The secondary fuel nozzle 3 is configured to function as a pilot burner that keeps the combustion of the burner 2 by burning the fuel F at the start of operation and a burner for quickly warming up. Can do.

  Further, the combustion gas G that has flowed from the upstream passage 10a into the shaft passage 10b having a smaller diameter than the upstream passage 10a flows to the shaft passage 10b along the central axis X at a relatively high speed while turning. The combustion gas G that has flowed from the shaft passage 10b into the downstream passage 10c having a larger diameter than the shaft passage 10b flows to the downstream passage 10c in the radially outward direction at a relatively low speed while turning, and then the downstream passage It flows out from the exhaust port 15 formed outside 10c.

As for the heat transfer tubes 11 arranged coaxially over a plurality of portions whose distances from the central axis X are different from each other, a region outside the outer shape of the axial passage 10b of the downstream passage 10c is helically formed in the central axis X. The evaporator tube 11a which consists of the heat exchanger tube arrange | positioned with the form which swirls is provided, and the superheater tube 11b which consists of the heat exchanger tube arrange | positioned with the shaft part path | route 10b helically turning the center axis | shaft X is provided. The superheat pipe 11b is arranged from the inside of the cylindrical protrusion 6 constituting the shaft passage 10b to the downstream passage 10c.
Note that turning the central axis X helically means turning three-dimensionally around the central axis X while moving in one direction along the central axis X.

  The heat transfer tubes 11 are formed so as to rotate helically in a state in which they are spaced apart from each other in the direction along the central axis X, and are adjacent to each other in the direction along the central axis X. The combustion gas G can circulate well in the gap formed between the two.

  And the evaporation pipe | tube 11a is arrange | positioned so that the supplied water W may be distribute | circulated in the heat exchanger tube 11 toward upper direction from the downward direction. A sufficient amount of heat is transferred from the combustion gas G flowing through the downstream passage 10c at a relatively low speed to heat and evaporate the water W, thereby generating saturated steam S ′. Yes.

  On the other hand, the superheater tube 11b is arranged so that the saturated steam S 'supplied from the evaporator tube 11a flows through the heat transfer tube 11 from the upper side to the lower side. Then, the saturated steam S ′ is superheated to a high temperature from the high-temperature combustion gas G that circulates relatively upstream in the downstream portion passage 10c and further from the high-temperature combustion gas G that circulates at relatively high speed in the shaft portion passage 10b. Therefore, the high-temperature heat suitable for the heat transfer is satisfactorily transmitted, and the saturated steam S ′ is superheated to a high temperature to generate the high-temperature superheated steam S.

The partition member 7 that partitions the upstream passage 10a and the downstream passage 10b is integrally formed with a steam drum 8 that is formed in a ring shape between the evaporation pipe 11a and the superheat pipe 11b and that has a circular cross section. The steam drum 8 is configured to separate the water W that has not evaporated from the saturated steam S ′ supplied from the evaporation pipe 11a and supply the saturated steam S ′ to the superheated pipe 11b.
The outer wall of the steam drum 8 also contributes as a heat receiving surface that receives heat from the combustion gas G flowing in the combustion gas flow path 10, and can heat and separate the separated water W.
Further, a part of the water W separated by the steam drum 8 is partially discharged to prevent the concentration of impurities as necessary.

[Second Embodiment]
The boiler device 52 of the second embodiment shown in FIG. 2 omits the description of the same configuration as the first embodiment described above, but the heat transfer tube 11 constituting the superheater tube 11b is in the direction along the central axis X. Are arranged so as to turn in a helical shape while being in close contact with each other.

  In other words, the superheater tube 11b is configured as a close contact portion 25 that spirally turns in a state in which the heat transfer tubes 11 from the vicinity of the steam drum 8 to the lower end thereof are in close contact with each other in the direction along the central axis X.

Therefore, as described in the first embodiment, the contact portion 25 also functions as the cylindrical protrusion 6 (see FIG. 1) for promoting the circulation of the combustion gas G. The cylindrical protrusion 6 can be omitted.
Further, the close contact portion 25 also acts as the heat transfer tube 11 that receives heat from the combustion gas G, and an effective heat transfer area is ensured.

  Moreover, in the said 1st and 2nd embodiment, the state which separated the heat exchanger tube 11 which comprises the evaporation pipe 11a arrange | positioned along the inner surface of the main body casing 1 in the downstream part channel | path 10c in the direction along the central axis X. However, if the heat transfer tube 11 is formed so as to swirl along the inner surface of the main body casing 1 in a state of being closely attached in the direction along the central axis X, Since the combustion gas G is suppressed from reaching the inner surface side of the main casing 1, the excessively high temperature of the main casing 1 is suppressed.

[Third embodiment]
The boiler device 53 of the second embodiment shown in FIG. 3 omits the description of the same configuration as the first or second embodiment described above, but the heat transfer tube 11 constituting the evaporation tube 11a is not helical. The center axis X is configured to turn in a spiral shape.
Note that turning the central axis X in a spiral shape means that the central axis X does not move along the central axis X, but rotates around the central axis X while rotating in a plane while gradually reducing or increasing the rotational radius. .
Further, in the present embodiment, the heat transfer tubes 11 that rotate around the central axis X in a spiral shape are arranged in a double manner along the central axis X, and an effective heat transfer area is ensured.
Further, the steam drum 8 is configured to have a square cross-sectional shape, and is further arranged in the steam drum 8 in a form of partitioning the top and bottom in order to satisfactorily separate the water W from the saturated steam S ′. A plate-like separation wall 8a having a large number of holes is provided. Then, the saturated steam S ′ is supplied from the evaporation pipe 11a to the lower side of the separation wall 8a, and the saturated steam S ′ flows out to the upper side through the hole formed in the separation wall 8a. It will be supplied to the superheater tube 11b.

  Further, the heat transfer tube 11 constituting the superheater tube 11b revolves around the central axis X in a helical manner as in the first to second embodiments described above, but has an appropriate flow state of the combustion gas G. Therefore, the upper turning radius is formed smaller than the lower turning radius.

  In each of the above-described embodiments, the boiler device 50 is configured to take out the superheated steam S by providing the superheat pipe 11b, but separately configured to take out the saturated steam S ′ provided with only the steam generation unit 11a. It doesn't matter.

  The boiler apparatus according to the present invention can supply a small amount of steam, particularly superheated steam, in a stable and heat efficient manner, particularly for household use or small-scale business use, and water (or steam) in a heat transfer tube. The present invention can be effectively used as a burner heating type boiler apparatus capable of suppressing uneven flow and non-uniform flow of combustion gas in the combustion gas flow path.

Schematic configuration diagram of the boiler device of the first embodiment Schematic block diagram of the boiler device of the second embodiment Schematic block diagram of the boiler device of the third embodiment

Explanation of symbols

2: Burner 6: Cylindrical protrusion 8: Steam drum 10: Combustion gas channel 10b: Shaft channel 10c: Downstream channel 10a: Upstream channel 11: Heat transfer tube 11a: Evaporating tube 11b: Superheated tubes 50, 51, 52, 53: Boiler device A: Combustion air F: Fuel G: Combustion gas S: Superheated steam S ': Saturated steam W: Water X: Center axis

Claims (6)

Combustion in which a heat transfer tube is disposed in a combustion gas flow path in which the combustion gas of the burner circulates so as to swivel the central axis of the combustion gas flow path, and the water supplied into the heat transfer pipe flows through the combustion gas flow path A boiler device that generates steam by heating with gas,
The combustion gas flow path is divided into an upstream portion passage having the burner on an axis thereof and a downstream portion passage communicating with the upstream portion passage, and has a smaller diameter than the upstream portion passage and the downstream portion passage, A shaft passage through which the combustion gas flowing along the outer wall of the upstream passage flows to the downstream passage along the central axis is provided in the upstream passage so as to protrude toward the burner.
In the downstream passage, an evaporation pipe for evaporating the supplied water is arranged as the heat transfer pipe,
In the shaft passage, a superheat pipe that superheats the steam supplied from the evaporation pipe is arranged as the heat transfer pipe,
The said evaporation pipe is a boiler apparatus arrange | positioned coaxially with the said superheat pipe in the site | part from which the distance from the said central axis differs from the said superheat pipe.   The boiler apparatus according to claim 1, wherein an annular steam drum that separates water from steam supplied from the evaporation pipe and supplies the steam to the superheat pipe is disposed in the combustion gas flow path.   The boiler apparatus according to claim 1, wherein a cylindrical projecting portion that projects from the outer wall side of the shaft portion passage toward the upstream portion passage side is formed.   The boiler apparatus as described in any one of Claims 1-3 comprised so that the said burner may turn combustion gas centering | focusing on the said central axis. The boiler apparatus as described in any one of Claims 1-4 currently formed so that the heat exchanger tube which comprises the said superheater tube may rotate helically, mutually adhering in the direction along the said central axis. The boiler device according to any one of claims 1 to 5, wherein an outer wall of the combustion gas passage has an air cooling structure, and air after cooling the outer wall is supplied as combustion air for the burner. .

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