CN108980828B

CN108980828B - Combustion apparatus

Info

Publication number: CN108980828B
Application number: CN201810329521.XA
Authority: CN
Inventors: 小代卓史
Original assignee: Rinnai Corp
Current assignee: Rinnai Corp
Priority date: 2017-05-31
Filing date: 2018-04-13
Publication date: 2022-03-29
Anticipated expiration: 2038-04-13
Also published as: JP6853115B2; JP2018204808A; CN108980828A

Abstract

A combustion apparatus in which combustion gas from a plurality of flat burners arranged in a combustion chamber in a combustion basket is sucked and discharged to the outside by an exhaust fan, secondary air is supplied to the combustion chamber from distribution holes formed in a partition plate on the lower surface of the combustion chamber, and primary air is supplied to an inlet port communicating with an inlet port at the lower tip of the flat burner, which is provided in a rising plate rising from the tip of the partition plate, through a space between a gas manifold and the rising plate. A first air passage and a second air passage are provided to communicate the lower part and the upper part of the space between the gas manifold and the rising plate with the external space of the combustion basket. Further, the gas manifold has formed on its rear surface: a first inclined guide surface facing the first air passage and inclined downward and forward; and a second inclined guide surface facing the second vent passage and inclined upward and forward.

Description

Combustion apparatus

Technical Field

The present invention relates to a combustion apparatus including a combustion basket, in which a plurality of flat burners having flame ports long in the front-rear direction at the upper ends are arranged in the lateral direction in a combustion chamber, and combustion gas generated by combustion of a mixed gas discharged from the flame ports of the flat burners is sucked by an exhaust fan and discharged to the outside.

Background

Conventionally, as such a combustion apparatus, a combustion apparatus in which: a partition plate of a lower surface of the combustion chamber; and a standing plate standing from the front end of the partition plate along the front end of the lower part of the flat combustor, wherein the standing plate is provided with respective inlet ports communicating with the inlet ports opened at the front end of the lower part of the flat combustors, a gas manifold in which respective gas nozzles facing the respective inlet ports are protrudingly provided on the rear surface is disposed to face the front of the standing plate, primary air is supplied from the space between the gas manifold and the standing plate to the inlet ports of the flat combustors via the respective inlet ports, and secondary air is supplied to the combustion chamber via a plurality of distribution holes formed in the partition plate. In this combustion apparatus, the combustion basket is provided with a bottom plate located below the partition plate, an air supply chamber communicating with the space outside the combustion basket through an air supply port formed in the bottom plate is defined between the bottom plate and the partition plate, and the space between the gas manifold and the rising plate is communicated with the air supply chamber.

In the above-described configuration of the conventional example, the air in the air supply chamber is easily supplied as the secondary air to the combustion chamber through the distribution holes by the suction force of the exhaust fan, and the primary air supplied from the air supply chamber to the inlet port of the flat burner through the space between the gas manifold and the rising plate is likely to be insufficient. In order to reduce the proportion of air supplied as secondary air in the supply air chamber and eliminate the shortage of primary air, it is necessary to reduce the number of distribution holes. However, since the ventilation resistance is increased, the fan rotation speed needs to be increased, which increases power consumption and fan noise.

Patent document

Patent document 1: japanese patent laid-open publication No. 2016-29316

Disclosure of Invention

In view of the above problems, an object of the present invention is to provide a combustion apparatus capable of eliminating the shortage of primary air without reducing the number of distribution holes.

In order to solve the above problems, a combustion apparatus according to the present invention includes a combustion basket, in which a plurality of flat burners having flame ports long in a front-rear direction at an upper end are arranged in a horizontal direction in a combustion chamber, and combustion gas generated by combustion of a mixed gas discharged from the flame ports of the flat burners is sucked and discharged to the outside by an exhaust fan, the combustion basket including: a partition plate of a lower surface of the combustion chamber; and a rising plate rising from a front end of the partition plate along a front end of a lower portion of the flat combustor, the rising plate being provided with respective inlet ports communicating with inlet ports opened at the front end of the lower portion of the flat combustors, a gas manifold being disposed to face a front side of the rising plate, respective gas nozzles being provided to protrude from a rear surface of the gas manifold so as to face the respective inlet ports, primary air being supplied from a space between the gas manifold and the rising plate to the inlet ports of the flat combustors via the respective inlet ports, and secondary air being supplied to the combustion chamber via a plurality of distribution holes formed in the partition plate, the combustion apparatus being characterized by comprising: a first air passage for communicating a lower portion of a space between the gas manifold and the standing plate with an external space of the combustion basket; and a second air passage that communicates an upper portion of a space between the gas manifold and the rising plate with an external space of the combustion basket, and a rear surface of the gas manifold is formed with at least one of a first inclined guide surface of a lower portion that faces the first air passage and is inclined forward and downward and a second inclined guide surface of an upper portion that faces the second air passage and is inclined forward and upward.

According to the present invention, since the space between the gas manifold and the rising plate communicates with the space outside the combustion basket through the first air passage and the second air passage, air flows from the space outside the combustion basket into the space between the gas manifold and the rising plate through the air passages without being affected by the suction force of the exhaust fan acting through the distribution holes, and primary air is supplied from the space to the inlet port of the flat burner through the inlet port. The primary air flowing in from at least one of the first air passage and the second air passage flows along at least one of the first inclined guide surface and the second inclined guide surface toward the inlet port, and the primary air is smoothly supplied to the inlet port of the flat burner. Therefore, the shortage of primary air can be eliminated without reducing the number of distribution holes formed in the partition plate. As a result, the number of rotations of the exhaust fan is not increased, and problems such as an increase in power consumption and an increase in fan noise can be prevented.

In the present invention, when the first inclined guide plate is formed on the rear surface of the gas manifold, it is preferable to provide the first inclined guide plate extending obliquely forward and downward from the vicinity of the lower end of the introduction port, and to define the first air passage between the first inclined guide plate and the first inclined guide plate, and when the second inclined guide plate is formed on the rear surface of the gas manifold, it is preferable to provide the second inclined guide plate extending obliquely forward and upward from the vicinity of the upper end of the introduction port, and to define the second air passage between the second inclined guide plate and the second inclined guide plate. Accordingly, the primary air can smoothly flow from each of the first and second air passages to the inlet.

In this case, it is preferable that at least one of an interval between the first inclined guide surface and the first inclined guide plate and an interval between the second inclined guide surface and the second inclined guide plate becomes larger as going forward. Accordingly, more primary air can flow into the interval that becomes larger as it goes forward, and the amount of primary air supplied to the inlet of the flat burner can be increased.

Further, an inclined folded portion inclined downward toward the rear may be provided at the front end of the first inclined guide plate, or an inclined folded portion inclined upward toward the rear may be provided at the front end of the second inclined guide plate. Accordingly, more primary air can be introduced into the first air passage and the second air passage by being guided to the obliquely folded portion from below and above.

Further, it is preferable that a cross-sectional shape of a lateral portion of at least one of the first inclined guide plate and the second inclined guide plate corresponding to each introduction port is curved in an arc shape in a direction away from an inclined guide surface facing the inclined guide plate out of the first inclined guide surface and the second inclined guide surface. Accordingly, the primary air can smoothly flow along the arcuately curved portions of the inclined guide plate to the respective inlets.

Further, a recessed portion may be formed in at least one of the first and second inclined guide surfaces, the recessed portion being located at a lateral portion corresponding to each introduction port and extending in the front-rear direction. Accordingly, the primary air can smoothly flow to the introduction ports along the respective concave portions.

In addition, in the present invention, the following configuration may be adopted: a second inclined guide surface is formed on the rear surface of the gas manifold, and the flat burner is composed of a rich-lean burner, and the rich-lean burner has, as flame ports: a light flame port through which a light mixed gas having a fuel concentration leaner than a theoretical air-fuel ratio is ejected; and a rich flame port through which a rich mixture gas having a fuel concentration higher than that of a lean mixture gas is discharged as an inflow port, the rich-lean burner including: a light-inlet port for a light flame port; and a rich-flame inlet for a rich flame port, which is located above the lean-flame inlet, and which has an inlet opening formed in the rising plate: a light inlet port communicating with the light inlet port; and a rich inlet port communicating with the rich inlet port, wherein, when a lean gas nozzle facing the lean inlet port and a rich gas nozzle facing the rich inlet port are provided as the gas nozzles in a protruding manner on the rear surface of the gas manifold, a recessed portion is formed on the second inclined guide surface, the recessed portion being located in a lateral portion corresponding to a spacing portion between the respective rich inlet ports adjacent in the lateral direction and extending in the front-rear direction. Accordingly, the amount of primary air flowing from the second air passage to the light inlet can be increased, and the amount of primary air supplied to the rich inlet via the rich inlet can be decreased.

Drawings

Fig. 1 is a perspective view of a combustion apparatus according to a first embodiment of the present invention.

Fig. 2 is a sectional side view taken along line II-II in fig. 1.

Fig. 3 is an enlarged sectional view of an upper portion of a flat burner used in the combustion apparatus of the embodiment.

Fig. 4 is a sectional side view of a main part of the combustion apparatus of the second embodiment.

Fig. 5 is a sectional side view of a main part of the combustion apparatus of the third embodiment.

Fig. 6 is a perspective view of a main part of a combustion apparatus according to a third embodiment in a state where a gas manifold is removed.

Fig. 7 is a sectional side view of a main part of a combustion apparatus of a fourth embodiment.

Fig. 8 is a perspective view of a gas manifold used in the combustion apparatus of the fourth embodiment.

Fig. 9 is a sectional side view of a main part of a combustion apparatus of a fifth embodiment.

Fig. 10 is a perspective view of a gas manifold used in the combustion apparatus of the fifth embodiment.

Description of the reference numerals

1 … combustion basket, 1a … combustion chamber, 2 … flat burner, 21 … light flame port, 22 … rich flame port, 23 … light inlet port, 24 … rich inlet port, 3 … divider plate, 31 … distribution hole, 4 … rising plate, 41 … light inlet port, 42 … rich inlet port, 6 … gas manifold, 61 … light gas nozzle, 62 … rich gas nozzle, 7 … first air passage, 71 … first oblique guide surface, 711 … groove portion, 72 … first oblique guide plate, 721 … oblique folded portion, 722 … arc curved shape portion, 8 … second air passage, 3681 second oblique guide surface, 36811 groove portion, 82 … second oblique guide plate, 821 … oblique folded portion, … arc curved shape portion.

Detailed Description

Referring to fig. 1 and 2, the combustion apparatus according to the embodiment of the present invention includes a combustion basket 1. A plurality of flat burners 2 are arranged in a horizontal direction in a combustion chamber 1a in a combustion basket 1, and the flat burners 2 include: a flame port of which the upper end is longer in the front-rear direction; and an inflow port opened at a front end of the lower portion. Further, the front plate portion 11 at the upper portion of the front surface of the combustion basket 1 is provided with: an ignition electrode 12 and a flame rod 13 facing the upper side of the flat burner 2; and a viewing window 14. Although not shown, the combustion gas generated by the combustion of the mixed gas discharged from the flame ports of the flat burner 2 is sucked into the exhaust fan after passing through the heat exchanger and is discharged to the outside.

As shown in fig. 3, the flat burner 2 of the present embodiment is composed of a rich-lean burner having, as flame ports: a light flame port 21 for ejecting a light mixture gas whose fuel concentration is leaner than a theoretical air-fuel ratio through the light flame port 21; and rich flame ports 22 which are located on both lateral sides of the lean flame port 21, and which eject a rich mixture gas having a fuel concentration that is richer than the fuel concentration of the lean mixture gas by the rich flame ports 22, and which are provided as an inflow port, the rich-lean burner comprising: a light-ends inlet 23 for the light-ends flame port 21; and a rich-gas inlet 24 for the rich flame port 22, which is located above the lean-gas inlet 23. A plurality of rectifying plates 21a are mounted in the thin flame ports 21. On both sides of the light flame ports 21, return regions 21b are provided which are located between the light flame ports 21 and the rich flame ports 22 and which do not eject the mixed gas.

Provided in the combustion basket 1 are: a partition plate 3 on the lower surface of the combustion chamber 1 a; and a rising plate 4 rising from the front end of the partition plate 3 along the lower front end of the flat burner 2. A plurality of distribution holes 31 are formed in the partition plate 3. Then, the secondary air is supplied to the combustion chamber 1a through the distribution holes 31 by the suction force of the exhaust fan. In the present embodiment, the bottom surface of the combustion basket 1 located below the partition plate 3 is open, but the bottom surface may be closed by a bottom plate, so that air flowing in from an air supply port opened in the bottom plate is supplied as secondary air to the combustion chamber 1a through the distribution holes 31.

The rising plate 4 is provided with a light inlet 41 and a rich inlet 42 which communicate with the light inlet 23 and the rich inlet 24 of each flat burner 2, respectively. Further, a baffle 5 is provided on the front surface of the rising plate 4, and the baffle 5 has an opening portion overlapping the light inlet 41 and the rich inlet 42. The upper end of the rising plate 4 is bent forward and reaches the lower end of the front plate 11.

The gas manifold 6 is disposed to face the front of the rising plate 4. A rear surface of the gas manifold 6 is provided with: the fresh gas nozzles 61 facing the fresh gas introduction ports 41; and rich gas nozzles 62 facing the rich introduction ports 42. The gas injected from each of the light gas nozzles 61 is supplied to the light-gas inlet 23 of each of the flat combustors 2 through each of the light-gas inlet ports 41, primary air is supplied to the light-gas inlet 23 of each of the flat combustors 2 through each of the light-gas inlet ports 41 from the space between the gas manifold 6 and the rising plate 4, and a light mixed gas generated by mixing the gas and the primary air in the mixing passage in the flat combustor 2 connected to the light-gas inlet 23 is ejected from the light-gas flame port 21. The fuel gas injected from each of the rich gas nozzles 62 is supplied to the rich inlet 24 of each of the flat combustors 2 through each of the rich inlet ports 42, primary air is supplied to the rich inlet 24 of each of the flat combustors 2 through each of the rich inlet ports 42 from a space between the fuel gas manifold 6 and the rising plate 4, and a rich mixed gas generated by mixing the fuel gas and the primary air in the mixing passage in the flat combustor 2 connected to the rich inlet 24 is ejected from the rich flame port 22.

Here, in the present embodiment, there are provided: a first air passage 7 for communicating a lower portion of a space between the gas manifold 6 and the rising plate 4 with an external space of the combustion basket 1; and a second air passage 8 for communicating an upper portion of a space between the gas manifold 6 and the rising plate 4 with an external space of the combustion basket 1. Further, on the rear surface of the gas manifold 6, there are formed: a lower first inclined guide surface 71 facing the first air passage 7 and inclined forward and downward; and an upper second inclined guide surface 81 facing the second air passage 8 and inclined forward and upward.

Accordingly, the space between the gas manifold 6 and the upright plate 4 communicates with the space outside the combustion basket 1 through the first air passage 7 and the second air passage 8, and therefore, air flows from the space outside the combustion basket 1 into the space between the gas manifold 6 and the upright plate 4 through the

air passages

7 and 8 without being affected by the suction force of the exhaust fan acting through the distribution holes 31, and primary air is supplied from the space to the light inlet port 23 and the rich inlet port 24 of the flat burner 2 through the light inlet port 41 and the rich inlet port 42. The primary air flowing in from the first air passage 7 and the second air passage 8 flows along the first inclined guide surface 71 and the second inclined guide surface 81 toward the light inlet port 41 and the rich inlet port 42, and thus the primary air is smoothly supplied to the light inlet port 23 and the rich inlet port 24 of the flat burner 2 through the

respective inlet ports

41 and 42. Therefore, the shortage of primary air can be eliminated without reducing the number of distribution holes 31 formed in the partition plate 3. As a result, it is not necessary to increase the rotation speed of the exhaust fan, and it is possible to prevent problems such as an increase in power consumption and an increase in fan noise.

In the present embodiment, the present invention is provided with: a first inclined guide plate 72 extending obliquely forward and downward from the vicinity of the lower end of the inlet port opened in the rising plate 4, specifically, from the vicinity of the lower end of the fresh inlet port 41 located downward, and defining a first air passage 7 with the first inclined guide surface 71; and a second inclined guide plate 82 extending obliquely forward and upward from the vicinity of the upper end of the inlet port opened in the rising plate 4, specifically, from the vicinity of the upper end of the rich inlet port 42 located upward, and defining a second air passage 8 with the second inclined guide surface 81. This enables the primary air to flow more smoothly from the first and

second air passages

7, 8 to the light and

rich inlets

41, 42. In the present embodiment, in order to reduce the number of components, two inclined guide plates, i.e., the first inclined guide plate 72 and the second inclined guide plate 82, are formed integrally with the baffle 5.

Further, the distance between the first inclined guide surface 71 and the first inclined guide plate 72 increases as going forward. Accordingly, the amount of primary air flowing into the first air passage 7 can be increased, and the amount of primary air supplied to the light-inlet 23 of the flat burner 2 can be increased. Further, the distance between the second inclined guide surface 81 and the second inclined guide plate 82 can be made larger as going forward, and the amount of primary air supplied to the rich inlet 24 of the flat burner 2 can be increased.

Further, an inclined folded portion 721 inclined rearward and downward is provided at the front end of the first inclined guide plate 72, and an inclined folded portion 821 inclined rearward and upward is provided at the front end of the second inclined guide plate 82. Accordingly, more primary air can be introduced into the first air passage 7 from below through the obliquely folded portion 721, and more primary air can be introduced into the second air passage 8 from above through the obliquely folded portion 821.

However, in the first embodiment described above, the lean gas nozzle 61 is provided with: the light gas introduction port 41 faces the center in the vertical direction, but the position of the light gas nozzle 61 may be shifted upward from that of the first embodiment as in the second embodiment shown in fig. 4. Accordingly, the primary air easily enters the fresh air inlet 41 at a position below the fresh gas nozzle 61, and the amount of primary air supplied to the fresh air inlet 23 can be increased. Further, the amount of primary air supplied to the rich inlet 24 can be increased by offsetting the position of the rich gas nozzle 62 downward.

Next, a third embodiment shown in fig. 5 and 6 will be explained. In the third embodiment, the cross-sectional shape of the lateral portion of the first inclined guide plate 72 corresponding to each light inlet 41 is curved in an arc shape in a direction away from the first inclined guide surface 71 facing the first inclined guide plate 72, and the cross-sectional shape of the lateral portion of the second inclined guide plate 82 corresponding to each rich inlet 42 is also curved in an arc shape in a direction away from the first inclined guide surface 81 facing the second inclined guide plate 82. Accordingly, the primary air can smoothly flow along the arcuate

curved portions

722 and 822 of the first inclined guide plate 72 and the second inclined guide plate 82 to the light inlet 41 and the rich inlet 42. Further, only one of the first inclined guide plate 72 and the second inclined guide plate 82 may be formed in the shape of the third embodiment.

Next, a fourth embodiment shown in fig. 7 and 8 will be explained. In the fourth embodiment, the first inclined guide surface 71 is formed with the recessed groove 711, and the recessed groove 711 is located at a lateral portion corresponding to each of the light fuel gas introduction ports 41, that is, a lateral portion corresponding to each of the light fuel gas nozzles 61 and extends in the front-rear direction. Accordingly, the primary air can smoothly flow to the light inlet 41 along the concave portions 711. Further, a recessed portion may be formed in the second inclined guide surface 81 at a lateral portion corresponding to each rich introduction port 42 and extending in the front-rear direction. This enables the primary air to smoothly flow to each rich inlet 42.

Next, a fifth embodiment shown in fig. 9 and 10 will be described. In the fifth embodiment, the second inclined guide surface 81 is formed with a recessed groove portion 811, and the recessed groove portion 811 is located at a lateral portion corresponding to a spacing portion between the

rich inlets

42, 42 adjacent in the lateral direction, that is, a lateral portion corresponding to a spacing portion between the

rich gas nozzles

62, 62 adjacent in the lateral direction, and extends in the front-rear direction. Accordingly, the primary air flowing along the concave portion 811 easily flows toward the lower fresh air inlet 41. Therefore, the amount of the primary air flowing from the second air passage 8 to the light inlet 41 can be increased, and the amount of the primary air supplied to the rich inlet 24 through the rich inlet 42 can be reduced. This makes it possible to appropriately adjust the air-fuel ratio of the rich air-fuel mixture.

The embodiments of the present invention have been described above with reference to the drawings, but the present invention is not limited thereto. For example, in the above embodiment, two inclined guide surfaces, i.e., the first inclined guide surface 71 and the second inclined guide surface 81, are formed on the rear surface of the gas manifold 6, but only one of the first inclined guide surface 71 and the second inclined guide surface 81 may be formed. In the above embodiment, the flat burner 2 is constituted by a rich burner, but may be constituted by a general bunsen burner. In this case, the rising plate 4 may be provided with an inlet port communicating with a single inlet port opened at the lower end of each flat burner, and the primary air may be caused to flow into the inlet port via the first ventilation path 7 and the second ventilation path 8.

Claims

1. A combustion apparatus comprising a combustion basket, wherein a plurality of flat burners are arranged in a horizontal direction in a combustion chamber in the combustion basket, each flat burner has a flame hole at an upper end thereof, the flame holes being long in the front-rear direction, and combustion gas generated by combustion of a gas mixture discharged from the flame holes of the flat burners is sucked and discharged to the outside by an exhaust fan, wherein the combustion basket is provided with: a partition plate of a lower surface of the combustion chamber; and a standing plate standing from the front end of the partition plate along the front end of the lower portion of the flat combustor, wherein the standing plate is provided with respective inlet ports communicating with the inlet ports opened at the front end of the lower portion of the flat combustors, a gas manifold is disposed to face the front of the standing plate, respective gas nozzles facing the respective inlet ports are provided to protrude from the rear surface of the gas manifold, primary air is supplied from a space between the gas manifold and the standing plate to the inlet ports of the flat combustors via the respective inlet ports, and secondary air is supplied to the combustion chamber via a plurality of distribution holes formed in the partition plate,

the combustion device is characterized in that,

the combustion apparatus is provided with: a first air passage for communicating a lower portion of a space between the gas manifold and the standing plate with an external space of the combustion basket; and a second air passage for communicating an upper portion of a space between the gas manifold and the rising plate with an external space of the combustion basket,

a first lower inclined guide surface is formed on a rear surface of the gas manifold, wherein the first inclined guide surface faces a first air passage and is inclined forward and downward, and the combustion apparatus is provided with a first inclined guide plate which extends obliquely forward and downward from a vicinity of a lower end of the introduction port and which defines the first air passage between the first inclined guide plate and the first inclined guide surface.

2. The combustion apparatus as claimed in claim 1,

the distance between the first inclined guide surface and the first inclined guide plate increases as going forward.

3. The combustion apparatus as claimed in claim 1 or 2,

an inclined turn-back portion inclined downward toward the rear is provided at the front end of the first inclined guide plate.

4. The combustion apparatus as claimed in claim 1 or 2,

the first inclined guide plate has a cross-sectional shape of a portion in the transverse direction corresponding to each of the introduction ports, and is curved in an arc shape in a direction away from the first inclined guide surface.

5. The combustion apparatus as claimed in claim 1,

the first inclined guide surface is formed on the rear surface of the gas manifold, and the first inclined guide surface is formed with a recessed portion that is located at a lateral portion corresponding to each of the introduction ports and extends in the front-rear direction.

6. A combustion apparatus comprising a combustion basket, wherein a plurality of flat burners are arranged in a horizontal direction in a combustion chamber in the combustion basket, each flat burner has a flame hole at an upper end thereof, the flame holes being long in the front-rear direction, and combustion gas generated by combustion of a gas mixture discharged from the flame holes of the flat burners is sucked and discharged to the outside by an exhaust fan, wherein the combustion basket is provided with: a partition plate of a lower surface of the combustion chamber; and a standing plate standing from the front end of the partition plate along the front end of the lower portion of the flat combustor, wherein the standing plate is provided with respective inlet ports communicating with the inlet ports opened at the front end of the lower portion of the flat combustors, a gas manifold is disposed to face the front of the standing plate, respective gas nozzles facing the respective inlet ports are provided to protrude from the rear surface of the gas manifold, primary air is supplied from a space between the gas manifold and the standing plate to the inlet ports of the flat combustors via the respective inlet ports, and secondary air is supplied to the combustion chamber via a plurality of distribution holes formed in the partition plate,

the combustion device is characterized in that,

the combustion device is provided with a second inclined guide plate which extends obliquely upward from the vicinity of the lower end of the introduction port and which defines the second gas passage between the second inclined guide plate and the second inclined guide plate.

7. The combustion apparatus as claimed in claim 6,

the distance between the second inclined guide surface and the second inclined guide plate increases as going forward.

8. The combustion apparatus as claimed in claim 6 or 7,

an inclined turn-back portion inclined upward and rearward is provided at the front end of the second inclined guide plate.

9. The combustion apparatus as claimed in claim 6 or 7,

the second inclined guide plate has a cross-sectional shape of a portion in the transverse direction corresponding to each of the introduction ports, and is curved in an arc shape in a direction away from the second inclined guide surface.

10. The combustion apparatus as claimed in claim 6,

the second inclined guide surface is formed on the rear surface of the gas manifold, and a recessed portion is formed on the second inclined guide surface, the recessed portion being located at a lateral portion corresponding to each of the introduction ports and extending in the front-rear direction.

11. The combustion apparatus as claimed in claim 6,

the second inclined guide surface is formed on the rear surface of the gas manifold, and the flat burner is a rich-lean burner including, as the flame ports: a light flame port through which a light mixed gas having a fuel concentration leaner than a theoretical air-fuel ratio is ejected; and a rich flame port through which a rich mixture gas having a fuel concentration that is richer than a fuel concentration of a lean mixture gas is discharged, the rich flame port serving as the inflow port, the rich-lean burner including: a light-inlet port for a light flame port; and a rich-flame inlet for a rich flame port, which is located above the lean-flame inlet, and which is provided as the inlet, wherein the rising plate is provided with: a light inlet port communicating with the light inlet port; and a rich inlet port communicating with the rich inlet port, wherein a lean gas nozzle facing the lean inlet port and a rich gas nozzle facing the rich inlet port are protruded from a rear surface of the gas manifold as the gas nozzle, and a groove portion extending in the front-rear direction at a lateral portion corresponding to a spacing portion between the rich inlet ports adjacent in the lateral direction is formed on the second inclined guide surface.