JP2022003287A - Combustion device - Google Patents

Abstract

To decrease costs for a manifold 3, in a combustion device equipped with a plurality of burners 2 provided in parallel at a lower part in a combustion housing 1, the manifold 3 supplying combustion gas to these burners 2, a heat exchanger 4 heated by combustion gas from the burners 2, and a fan sucking the combustion gas passing through the heat exchanger 4, in which the manifold 3 is composed of a manifold body 3a protrusively provided with a plurality of nozzles 31 jetting out the combustion gas toward an inflow port 22 of a mixing pipe 21 of each burner 2, and a cover 3b defining a distribution chamber 32 of the fuel gas between the manifold body 3a and the cover 3b.SOLUTION: A manifold body 3a is formed by pressing a plate material. The projecting height of a nozzle 1 is set to be a height that can be drawn by pressing at a time.SELECTED DRAWING: Figure 2

Description

The present invention is heated by a combustion casing, a plurality of burners arranged side by side in the lower part of the combustion casing, a manifold for supplying fuel gas to the plurality of burners, and a combustion gas from a burner arranged in the upper part in the combustion casing. The present invention relates to a combustion device including a heat exchanger.

Conventionally, in this type of combustion device, generally, an air supply chamber is provided under the burner installation portion of the combustion casing, and a fan is connected to this air supply chamber. Then, the air from the fan is supplied to a plurality of burners as combustion air via the air supply chamber (see, for example, Patent Document 1). The front part of the air supply chamber is provided with a primary air chamber that rises upward and communicates with the inlet of the mixing pipe portion of each burner. Then, a manifold is attached so as to seal the front surface of the primary air chamber.

In this manifold, the manifold is a fuel gas between the manifold body and the manifold body, in which multiple nozzles that eject fuel gas toward the inlet of the mixing pipe of each burner are provided corresponding to multiple burners. It is composed of a cover that defines the distribution room of. Since the manifold body also functions as a lid plate for sealing the front surface of the primary air chamber, it is necessary to ensure flatness. Therefore, conventionally, the manifold body is used as a die-cast product to ensure flatness.

JP-A-2019-2594

By the way, some combustion devices are provided with a fan that sucks the combustion gas that has passed through the heat exchanger so that the combustion air is supplied to each burner by the suction force of the fan. In such an exhaust suction type combustion device, it is not necessary to seal the front surface of the primary air chamber described above with a manifold body. Therefore, it is not necessary to secure the flatness of the manifold body.

In view of the above points, it is an object of the present invention to provide an exhaust suction type combustion device capable of reducing costs by not using a die-cast manifold body. There is.

In order to solve the above problems, the present invention comprises a combustion casing, a plurality of burners arranged side by side in the lower portion of the combustion casing, a manifold for supplying fuel gas to these burners, and an upper portion in the combustion casing. A combustion device equipped with a heat exchanger that is heated by the combustion gas from the burner and a fan that sucks the combustion gas that has passed through the heat exchanger, so that combustion air is supplied to each burner by the suction force of the fan. In the manifold, the fuel gas is between the manifold body and the manifold body, in which a plurality of nozzles for ejecting fuel gas toward the inlet of the mixing pipe portion of each burner are provided corresponding to the plurality of burners. The manifold body is formed by pressing the plate material, and the protruding height of each nozzle can be drawn and molded by one pressing process. It is characterized by being set to a high height.

According to the present invention, by forming the manifold body by pressing the plate material, it is possible to reduce the cost as compared with the conventional example in which the manifold body is a die-cast product. Further, in the present invention, by setting the protruding height of the nozzle to a height that can be drawn by one press working, the number of press workings can be reduced and the cost can be reduced as much as possible. can.

If the manifold body is formed by pressing a plate material, it becomes difficult to secure the flatness of the manifold body. However, since the object of the present invention is an exhaust suction type combustion device, no problem occurs even if the flatness of the manifold body cannot be ensured.

By the way, in the distribution process of the combustion device, the load may be handled poorly and the combustion device may fall. Even if the inside of the device is damaged by dropping, if the member exposed on the outer surface of the device is sturdy and does not deform, there is a risk that the combustion device will be used as it is.

Here, the manifold generally has a fixed portion fixed to the combustion casing and an inflow portion of fuel gas located below the combustion casing. When the combustion device falls, a force (impact force) is applied to the manifold in the direction in which the fixed portion and the inflow portion approach each other. Therefore, it is desirable to form a notch in the manifold that becomes a stress concentration portion on which shear stress concentrates and acts by applying a force in the direction in which the fixed portion and the inflow portion approach each other. According to this, when the combustion device is dropped, the manifold is easily deformed and broken due to the notch. Therefore, it is possible to call attention not to use the combustion device as it is.

Further, with the juxtaposed direction of the plurality of burners as the lateral direction, the fixing portions are provided at least at the ends of the manifold on both sides in the lateral direction, and the notches are located closer to both ends in the lateral direction than the central portion in the lateral direction of the manifold. It is desirable to be provided in. According to this, stress concentration is likely to occur in the notch portion due to the downward force applied to the fixed portion due to the fall of the combustion device, and the certainty of deformation and breakage of the notch portion at the time of dropping is increased.

Further, it is more preferable that the fixing portion is provided only at the lateral end portions of the manifold and the inflow portion is provided at the lateral central portion of the manifold. According to this, stress concentration is more likely to occur in the notch portion when the combustion device is dropped, and the certainty of deformation and breakage of the notch portion at the time of dropping is further increased.

The perspective view of the combustion apparatus of embodiment of this invention. The cut side view cut by II-II of FIG. The perspective view seen from the diagonally lower side with the manifold of the combustion apparatus of embodiment separated. FIG. 3 is a perspective view seen from diagonally rearward of the manifold included in the combustion device of the embodiment. The perspective view seen from the diagonal front in the state where the manifold main body and the cover of the manifold provided in the combustion apparatus of embodiment are separated. FIG. 6 is an enlarged cross-sectional view of a nozzle portion cut along the VI-VI line of FIG.

With reference to FIGS. 1 and 2, the combustion apparatus of the embodiment of the present invention supplies a combustion casing 1, a plurality of burners 2 arranged side by side in the lower portion of the combustion casing 1, and fuel gas to these burners 2. The manifold 3 and the heat exchanger 4 heated by the combustion gas from the burner 2 arranged in the upper part of the combustion casing 1 are provided.

With the juxtaposed direction of the burners 2 as the lateral direction, each burner 2 is a flat burner having an elongated flame opening portion in the front-rear direction, which is a horizontal direction orthogonal to the lateral direction, at the upper end. A mixing pipe portion 21 is provided at the lower part of each burner 2. At the front end of the mixing pipe portion 21, an inflow port 22 that opens forward is provided. Then, the fuel gas ejected from each nozzle 31 described later in the manifold 3 flows into the inflow port 22 of each burner 2, and the primary air flows into the inflow port 22, and the fuel gas and the primary air are combined with each other in the mixing pipe portion 21. The air-fuel mixture is generated, and the air-fuel mixture is ejected from the flame port of the burner 2 and burned.

With reference to FIG. 3, a stepped portion 111 rising upward is formed on the front portion of the bottom plate 11 of the combustion casing 1. The step portion 111 is provided with an opening 112 facing the inflow port 22 of the mixing pipe portion 21 of each burner 2. In the present embodiment, since the six burners 2 are arranged side by side, six openings 112 are arranged side by side in the lateral direction. The bottom plate 11 is formed with a plurality of upward recesses 113 that sandwich the lower edge of each burner 2 from both sides in the lateral direction. Further, an electrode component 5 having an ignition electrode 51 for igniting the burner 2 and a frame rod 52 for detecting the flame of the burner 2 is mounted on the front plate 12 of the combustion casing 1.

The heat exchanger 4 is composed of a fin-and-tube type heat exchanger having a large number of endothermic fins 41 stacked in the lateral direction and a plurality of endothermic pipes 42 penetrating the endothermic fins 41. These endothermic pipes 42 are connected in series by a plurality of connecting pipes 43 curved in a U shape on the upper outer surface of the combustion casing 1. Then, the water supply pipe 44 is connected to the heat absorbing pipe 42 at the upstream end, and the hot water outlet pipe 45 is connected to the heat absorbing pipe 42 at the downstream end.

A fan 7 is connected to the upper end of the combustion casing 1 via an exhaust hood 6. A fan motor 71 is attached to the fan 7. The combustion gas that has passed through the heat exchanger 4 is sucked into the fan 7, and the combustion gas is discharged to the outside through an exhaust stack (not shown) connected to the outlet 72 of the fan 7. Further, as shown in FIG. 3, a large number of small holes 114 are formed in the bottom plate 11 of the combustion casing 1. Then, combustion air is supplied to each burner 2 by the suction force of the fan 7. That is, the air sucked from the inflow port 22 through each opening 112 is supplied to each burner 2 as the primary air for combustion, and the air sucked from the small hole 114 is supplied to each burner 2 as the secondary combustion air. It is supplied as air.

At the lower front end of the side plates 13 on both lateral sides of the combustion casing 1, a tongue piece portion 131 projecting forward from the step portion 111 of the bottom plate 11 is provided. Then, the manifold 3 is fixed to the tongue piece portion 131 with screws 34a in the fixing portions 34 provided at the ends on both sides in the lateral direction.

With reference to FIGS. 4 to 6, the manifold 3 has a plurality of nozzles 31 for ejecting fuel gas toward the inflow port 22 of the mixing pipe portion 21 of each burner 2 corresponding to the plurality of burners 2 (the present embodiment). 6) It is composed of a protruding manifold body 3a and a cover 3b that defines a fuel gas distribution chamber 32 between the manifold body 3a. The cover 3b is seam welded to the manifold body 3a at its peripheral edge. The manifold 3 further has an inflow port 33, which is an inflow portion of fuel gas, located below the combustion casing 1. The fixing portion 34 and the inflow port 33 described above are provided in the manifold body 3a. Fuel gas flows into the inflow port 33 via the valve unit 8 connected to the inlet 33. Then, the fuel gas flowing in from the inflow port 33 is distributed to each nozzle 31 through the distribution chamber 32, and is ejected from each nozzle 31 toward the inflow port 22 of the mixing pipe portion 21 of each burner 2.

Here, as in the present embodiment, in the exhaust suction type combustion device provided with the fan 7 for sucking the combustion gas that has passed through the heat exchanger 4, it is not necessary to secure the flatness of the manifold body 3a as described above. Therefore, in the present embodiment, the manifold body 3a is formed by pressing a plate material such as a stainless steel plate. As a result, the cost can be reduced as compared with the conventional example in which the manifold body 3a is a die-cast product. In this embodiment, the cover 3b is formed by pressing a plate material thinner than the material of the manifold body 3a.

Further, in the present embodiment, the protrusion height H (see FIG. 6) of the nozzle 31 is set to a height that can be drawn by one press working. For example, when the plate material of the manifold body 3a is a stainless steel plate (SUS304) having a plate thickness of 1.2 mm and the protrusion height H of the nozzle 31 is 4 mm, the nozzle 31 is squeezed by one press working. Can be molded. Then, the cost can be reduced as much as possible by drawing and forming the nozzle 31 by one press working.

Here, as shown in FIG. 6, each nozzle 31 has a tubular nozzle body 311 having an internal space 311a into which fuel gas flows from the distribution chamber 32, and a base end of the nozzle body 311 on the fuel gas inflow side. Is provided with an end wall portion 312 located on the opposite side. The end wall portion 312 is formed with a nozzle hole 313 from which the fuel gas flowing into the internal space 311a of the nozzle body 311 is ejected. When the protrusion height H of the nozzle 31 is set to a relatively small value that can be drawn and formed by one press working, the flow of combustion gas is not sufficiently rectified in the internal space 311a of the nozzle body 311 and the combustion performance is stable. Problems such as disappearance or the generation of so-called whistle blowing noise are likely to occur. Therefore, in the present embodiment, the base of the nozzle hole 313 located on the internal space 311a side of the nozzle body 311 is provided with a tapered portion 313a whose diameter gradually increases toward the internal space 311a of the nozzle body 311. According to this, even if the flow of fuel gas is not sufficiently rectified in the internal space 311a of the nozzle body 311, the flow of fuel gas is adjusted by the tapered portion 313a of the nozzle hole 313, the combustion performance is stabilized, and the whistle blows. The generation of sound can also be suppressed.

By the way, in the distribution process of the combustion device, the load may be handled poorly and the combustion device may fall. Even if the inside of the device is damaged by dropping, if the member exposed on the outer surface of the device is sturdy and does not deform, there is a risk that the combustion device will be used as it is.

Here, when the combustion device falls, a force (impact force) in a direction in which the fixing portion 34 and the inflow port 33 approach each other is applied to the manifold 3. Therefore, in the present embodiment, the manifold 3 is formed with a notch 35 which is a stress concentration portion on which the shear stress concentrates and acts due to the force applied in the direction in which the fixing portion 34 and the inflow port 33 approach each other. .. According to this, when the combustion device is dropped, the manifold 3 is easily deformed and broken by the notch 35, and it is possible to call attention not to use the combustion device as it is.

When the fixing portion 34 is provided at least at the ends on both sides in the lateral direction of the manifold 3, it is desirable that the notch 35 is provided at a position closer to the ends on both sides in the lateral direction than the central portion in the lateral direction of the manifold 3. According to this, stress concentration is likely to occur in the notch 35 due to the downward force applied to the fixed portion 34 when the combustion device is dropped, and the certainty of deformation and breakage of the notch 35 at the time of dropping is increased. In particular, in the present embodiment, the fixing portion 34 is provided only at the ends on both sides of the manifold main body 3a in the lateral direction, and the inflow port 33 is provided at the central portion in the lateral direction of the manifold main body 3a. A pair of upper and lower notches 35 are formed at positions closer to both ends in the lateral direction than the central portion in the lateral direction of the manifold body 3a. According to this, stress concentration is more likely to occur in the notch 35 when the combustion device is dropped, and the certainty of deformation and breakage of the notch 35 at the time of dropping is further increased.

Although the embodiments of the present invention have been described above with reference to the drawings, the present invention is not limited thereto. For example, in the above embodiment, the fixing portion 34 provided on the manifold main body 3a projects laterally outward from the cover 3b, but the fixing portion 34 provided on the manifold main body 3a is fixed at both ends in the lateral direction of the cover 3b. It is also possible to provide a fixed portion that overlaps the portion 34. In this case, the notch 35 may be formed on both the manifold main body 3a and the cover 3b so as to be located near the ends on both sides in the lateral direction.

1 ... Combustion casing, 2 ... Burner, 21 ... Mixing pipe section, 22 ... Inflow port, 3 ... Manifold, 3a ... Manifold body, 3b ... Cover, 31 ... Nozzle, 32 ... Distribution chamber, 33 ... Inflow port (inflow section) , 34 ... Fixed part, 35 ... Notch, 4 ... Heat exchanger, 7 ... Fan.

Claims (4)

A combustion case, a plurality of burners arranged side by side in the lower part of the combustion case, a manifold for supplying fuel gas to these burners, and a heat exchanger heated by the combustion gas from the burner arranged in the upper part in the combustion case. It is a combustion device equipped with a fan that sucks the combustion gas that has passed through the heat exchanger, and the combustion air is supplied to each burner by the suction force of the fan.
The manifold has a fuel gas distribution chamber between the manifold body and the manifold body, in which multiple nozzles that eject fuel gas toward the inlet of the mixing pipe of each burner are provided corresponding to multiple burners. In what is composed of a cover that is imaged,
The manifold body is formed by pressing a plate material, and the protruding height of each nozzle is set to a height that allows drawing and forming in one press working. The combustion apparatus according to claim 1, wherein the manifold has a fixed portion fixed to the combustion casing and a fuel gas inflow portion located below the combustion casing, and the manifold is fixed to the manifold. A combustion device characterized in that a notch is formed as a stress concentration portion on which shear stress concentrates and acts by applying a force in a direction in which the inflow portion approaches. The combustion device according to claim 2, wherein the plurality of burners are arranged side by side in the lateral direction, the fixing portions are provided at least at both ends in the lateral direction of the manifold, and the notches are formed in the manifold. A combustion device characterized in that it is installed closer to the ends on both sides in the lateral direction than the central portion in the lateral direction. The combustion device according to claim 3, wherein the fixing portion is provided only at both ends in the lateral direction of the manifold, and the inflow portion is provided at the central portion in the lateral direction of the manifold. Device.

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