JP6038632B2 - Combustion device - Google Patents

Description

  The present invention relates to a combustion apparatus including a light and dark burner, in which a flame rod is arranged to stop combustion when oxygen is lacking.

  Conventionally, a combustion housing has been provided, and a partition plate for partitioning the space in the combustion housing into a combustion chamber and a supply chamber below the combustion chamber has been provided, and a plurality of light and dark burners are arranged in the combustion chamber in the horizontal direction. A combustion apparatus that is provided side by side so that secondary air is supplied from a supply chamber to a combustion chamber through a number of distribution holes formed in a partition plate. It is known that a flame rod is disposed and combustion is stopped when the flame rod stops detecting flame by a flame lift when oxygen is lacking.

  In addition, the lean burner is located at the upper end of the pale flame outlet that is long in the front-rear direction for jetting a pale mixture whose fuel concentration is less than the stoichiometric air-fuel ratio, and the mixture is jetted on both sides of the pale flame mouth in the lateral direction. A blind flame that is located in the lateral direction outside the blind gap and has a rich flame outlet that ejects a rich fuel mixture having a fuel concentration higher than that of the pale air mixture. Is held by the rich flame formed at the rich flame opening and the reflux of the light mixture over the blind gap. Further, in order to improve the flame holding property of the rich flame, generally, the height of the upper end of the wall plate on the laterally outer side of the rich flame mouth is made higher than the upper end of the pale flame mouth and the blind gap.

  Here, when there is oxygen shortage, the combustion speed becomes lower than the jetting speed of the air-fuel mixture due to oxygen shortage, and flame lift occurs. However, in the light and dark burner, the light flame is lifted before the rich flame. And if a flame rod does not lift even to a deep flame, it will detect a flame, Therefore Combustion is not stopped.

  Therefore, conventionally, in the combustion apparatus as described above, there has been known one in which the amount of secondary air supplied to the portion of the dark and light burner facing the frame rod is larger than that of the other portions (see, for example, Patent Document 1). In this case, the rich flame formed at the rich flame opening located immediately below the frame rod is cooled by the secondary air supplied in a large amount, the combustion speed becomes slow, and the rich flame is easily lifted. Accordingly, not only the light flame but also the rich flame is lifted at the initial stage of lack of oxygen at the arrangement portion of the frame rod, and the flame rod does not detect the flame.

  However, increasing the supply amount of the secondary air, albeit partially, causes a decrease in the temperature of the combustion exhaust gas, and there is a problem in improving the thermal efficiency.

JP 2011-252671 A

  In view of the above points, an object of the present invention is to provide a combustion apparatus in which a flame rod does not detect a flame at an early stage of lack of oxygen without increasing the supply amount of secondary air.

In order to solve the above problems, the present invention includes a combustion housing, and a partition plate is provided in the combustion housing to partition the space in the combustion housing into a combustion chamber and a supply chamber below the combustion chamber. In the section, a pale flame outlet that is long in the front-and-rear direction for jetting a light mixture whose fuel concentration is leaner than the stoichiometric air-fuel ratio, a blind gap that is located on both sides of the pale flame mouth and in which no mixture is jetted, and a blind gap And has a rich flame outlet that ejects a rich mixture with a fuel concentration higher than that of the pale mixture, and the height of the upper end of the wall plate on the laterally outer side of the dense flame is the pale flame. Multiple burners arranged side by side in the combustion chamber are arranged in parallel in the combustion chamber, and the secondary air is supplied to the combustion chamber through a number of distribution holes formed in the partition plate. Combustion device adapted to be used, with a flame rod arranged above a predetermined light and dark burner, and a flame in the absence of oxygen When the flame rod stops detecting the flame at the bottom, the predetermined light and dark burner is located on the portion of the wall plate directly below the frame rod on the laterally outer wall plate of the thick flame opening. It is formed to have a recessed portion that is recessed below the upper end of the other portion, and the height of the bottom side of the recessed portion is equal to the height of the upper end of the blind gap .

  Here, when the recessed portion is formed in the wall plate, the secondary air flowing upward along the outer side surface of the wall plate enters the laterally inner side from the recessed portion and is easily mixed with the rich flame. For this reason, the amount of secondary air mixed into the rich flame increases at the recessed portion, the temperature of the rich flame decreases, and the rich flame tends to lift. Therefore, according to the present invention, even if the supply amount of secondary air is not increased, not only the light flame but also the rich flame is lifted at the initial stage of oxygen deficiency in the arrangement portion of the frame rod, so that the flame rod It will not be detected. As a result, combustion can be reliably stopped before the flammability deteriorates due to lack of oxygen, and deterioration of thermal efficiency can also be prevented.

  In addition, if the height of the bottom of the recessed portion is too high, the above-described effects cannot be obtained sufficiently. On the other hand, when the height of the bottom of the recessed portion is made lower than the height of the upper end of the blind gap, the plate member that defines the blind gap is beaten from the side by a rich flame that extends upward from the height of the bottom of the recessed portion. This adversely affects durability. Therefore, it is desirable that the height of the bottom side of the recessed portion is equal to the height of the upper end of the blind gap.

  By the way, in order to reduce the cost, the other dark and light burners other than the predetermined light and dark burner on which the frame rod is exposed are recessed in the light and dark burner of the same model as the predetermined light and dark burner, that is, the wall plate on the laterally outer side of the dark flame outlet. It is desirable to use a light and dark burner having a notch. However, in order to keep the CO concentration in the flue gas before the combustion stop as low as possible, prevent the rich flame from being easily lifted by the recessed portion of the wall plate outside the thick flame outlet of the other dark and light burners. Should.

  Therefore, it is desirable to provide a restricting member that restricts the supply of secondary air to the formation location of the recessed portion of the wall plate on the outer side in the lateral direction of the rich flame port of the other light and dark burner. According to this, the cooling of the rich flame by the secondary air in the recessed portion is suppressed, and the temperature of the rich flame does not decrease so much. Therefore, it is possible to effectively prevent the thick flame from being easily lifted by the recessed portions of the other light and dark burners.

  Note that the combustion apparatus generally includes a positioning member that engages with the front and rear ends of each light and dark burner to position each light and dark burner. If the limiting member is formed integrally with the positioning member, the number of parts does not increase, which is advantageous in avoiding an increase in cost.

The top view of the combustion apparatus of embodiment of this invention. Sectional drawing cut | disconnected by the II-II line | wire of FIG. The perspective view of the principal part of the predetermined density | concentration burner provided in the combustion apparatus of embodiment. (A) Sectional drawing cut | disconnected by the IVa-IVa line | wire of FIG. 3, (b) Sectional drawing cut | disconnected by the IVb-IVb line | wire of FIG.

  1 and 2, reference numeral 1 denotes a combustion housing. The upper surface of the combustion casing 1 is open, and an object to be heated such as a heat exchanger (not shown) is installed on the combustion casing 1.

  In the combustion housing 1, a partition plate 2 that partitions the space in the combustion housing 1 into a combustion chamber 11 and an air supply chamber 12 below the combustion chamber 11 is provided. A combustion fan (not shown) is connected to the bottom surface of the air supply chamber 12 via a duct 12a, and air is supplied from the combustion fan to the air supply chamber 12. A large number of distribution holes 2a are formed in the partition plate 2 so as to be positioned at the arrangement pitch portion of the light and dark burners 3 described later. The air supplied to the air supply chamber 12 is supplied as secondary air to the combustion chamber 11 through these distribution holes 2a.

In the combustion chamber 11, a plurality of dark and light burners 3 that are longitudinal in the front-rear direction are arranged in parallel in the horizontal direction. Positioning members 4 ₁ and 4 ₂ for the light and dark burner 3 are installed on the upper inner side of the front surface of the combustion housing 1 and the upper inner side of the rear surface, respectively. Each positioning member 4 ₁ , 4 ₂ has a comb-like claw portion 4 a at the lower end, and each claw burner 3 is engaged with each end portion in the front-rear direction of each light / dark burner 3, so that each light / dark burner is engaged. 3 is positioned.

  As shown in FIG. 3 and FIG. 4, each of the light and dark burners 3 has a light flame port 31 that is long in the front-rear direction for injecting a light air-fuel mixture whose fuel concentration is less than the stoichiometric air-fuel ratio. A blind gap 32 that is located on both sides in the lateral direction and in which no air-fuel mixture is ejected, and a rich flame port 33 that is located on the laterally outer side of the blind air gap 32 and ejects a rich air-fuel mixture that is richer in fuel concentration than a light air-fuel mixture Prepare. A plurality of rectifying plates 31 a are mounted in the pale flame port 31 with a gap in the horizontal direction. And the narrowing part 31b which divides the pale flame mouth 2 to the front-back direction is formed in the front-back several places of these current plate 31a, making the current-flow-rectifying plates 31a contact in a horizontal direction.

  The blind gap 32 is defined between the laterally outer rectifying plate 31a and the side plate 34 constituting the burner body located outside the lateral rectifying plate 31a. To prevent the air-fuel mixture from being supplied to the blind gap 32. Further, the rich flame port 33 is defined between the side plate 34 and the wall plate 35 disposed on the outer side in the lateral direction. In addition, the height of the upper end of the wall plate 35 is higher than the upper ends of the pale flame port 31 and the blind gap 32 in order to enhance the flame holding property. In addition, a plurality of front and rear recesses 35a are formed at the front and rear portions of the wall plate 35 to divide the rich flame port 33 in the front and rear direction. The bridge part 35b to be connected at is provided.

  Referring to FIG. 2, a light mixture inlet 36 is provided at the lower front end of the light and dark burner 3, and a rich mixture inlet 37 is provided on the upper side thereof. The fuel concentration of the rich air-fuel mixture is generally set to be higher than the stoichiometric air-fuel ratio, but can be set to be slightly leaner than the stoichiometric air-fuel ratio.

  Further, a rising portion 21 is bent at the front edge of the partition plate 2, and a manifold 5 is mounted on the front side of the rising portion 21 so as to close the lower front surface of the combustion housing 1. The manifold 5 is provided with gas nozzles 51 and 52 for the light mixture and the rich mixture that face the inlets 36 and 37 of the light and dark burners 3, respectively. The fuel gas is supplied from the gas nozzles 51 and 52 to the inlets 36 and 37, and the inlets 36 are formed from the supply chamber 12 through gaps defined between the rising portion 21 and the manifold 5. , 37 is supplied with primary air.

  A damper plate 22 having openings corresponding to the inlets 36 and 37 of the light and dark burners 3 is provided on the front surface of the rising portion 21. Then, the opening of the damper plate 22 corresponding to the inlet 36 for the light mixture is formed large so that the amount of primary air supplied to the inlet 36 is increased so that a light mixture is generated, The opening of the damper plate 22 corresponding to the air inlet 37 for the air-fuel mixture is formed small so that the amount of primary air supplied to the air inlet 37 is reduced so that a rich air-fuel mixture is generated.

  A spark plug 6 is attached to the front surface of the combustion housing 1 and a frame rod 7 is attached so as to face a predetermined light / dark burner 3. Specifically, the frame rod 7 is arranged so as to face the upper front part of the fifth and sixth light and dark burners 3 from the right side in FIG. When the flame rod 7 no longer detects flames due to a flame lift when there is oxygen deficiency, that is, the frame current flowing through the flame between the frame rod 7 and the predetermined light and dark burner 3 is higher than the frame rod 7. When the flame lift drops to below a predetermined threshold, the solenoid valve (not shown) provided in the gas supply path upstream of the manifold 5 is closed to stop the combustion.

  Here, if it becomes deficient in oxygen, the light flame formed in the light flame port 31 is lifted early, but the heavy flame formed in the heavy flame port 33 is difficult to lift. Is detected, and combustion cannot be stopped at the initial stage of lack of oxygen.

  Therefore, in the present embodiment, the predetermined light and dark burner 3 that the frame rod 7 faces is located in a portion located directly below the frame rod 7 of the wall plate 35 on the laterally outer side of the rich flame port 33, as shown in FIGS. As shown in FIG. 4B, the wall plate 35 is formed to have a recessed portion 35c that is recessed below the upper end of the other portion.

  Here, when the recess 35c is formed in the wall plate 35, the secondary air flowing upward along the outer surface of the wall plate 35 enters the inner side in the lateral direction from the recess 35c, and is easily mixed into the rich flame. . Therefore, in the recessed part 35c, the mixing amount of the secondary air to the rich flame increases, the temperature of the rich flame decreases, and the rich flame easily lifts due to the decrease in the combustion speed due to the temperature drop. Accordingly, not only the light flame but also the rich flame is lifted at the initial stage of lack of oxygen at the arrangement portion of the frame rod 7, and the frame rod 7 does not detect the flame. As a result, combustion can be reliably stopped before the flammability deteriorates due to lack of oxygen. Further, unlike the prior art, since it is not necessary to increase the amount of secondary air supplied to the portion where the frame rod 7 faces, the temperature of the combustion exhaust gas does not decrease due to the increase in the amount of secondary air, and deterioration of thermal efficiency can be prevented. .

  In addition, when the height of the bottom side of the recessed part 35c is too high, the above-described effects cannot be obtained sufficiently. On the other hand, when the height of the bottom side of the recess 35c is made lower than the height of the upper end of the blind gap 32, the side plate 34, which is a plate member that defines the blind gap 32, extends upward from the height of the bottom of the recess 35c. It is beaten from the side by a rich flame, and the durability is adversely affected. Therefore, as shown in FIG. 4B, the height of the bottom of the recessed portion 35c is equal to the height of the upper end of the blind gap 32 (even if it does not exactly match, the difference is slight and substantially the same. It is desirable that the

  Moreover, in this embodiment, the part which corresponds to the bridge part 35b of the upper end of the wall board 35 is also depressed below like the recessed part 35c. However, this portion is a portion that divides the rich flame opening 33 by a hollow 35a inward in the horizontal direction, and no rich flame is formed, so that it does not function like the recessed portion 35c.

  By the way, it is possible to form only the predetermined light and dark burner 3 that faces the frame rod 7 into the wall plate 35 having the recess 35c. However, in this embodiment, in order to reduce the cost, the frame rod 7 The other light and dark burners 3 other than the predetermined light and dark burner 3 are exposed to a light and dark burner of the same model as the predetermined light and dark burner, that is, a light and dark burner having a recess 35c in the wall plate 35. In this case, in order to keep the CO concentration in the combustion exhaust gas before the combustion stop as low as possible, it is necessary to prevent the rich flame from being easily lifted by the recessed portion 35c of the other light and dark burner 3.

Therefore, a restricting member 8 is provided for restricting the supply of secondary air to the location where the recessed portion 35c of the wall plate 35 of the other light and dark burner 3 is formed. In this embodiment, the claw portion 4a of the positioning member 4 ₁ of the lower end is provided on the front side of the combustion housing 1, the other shades burner 3 of the arrangement pitch portions so as to close concave portion 35c (the flame rod 7) A tongue piece extending to the same longitudinal position is extended, and the restricting member 8 is constituted by this tongue piece.

According to this, the cooling of the rich flame by the secondary air at the recessed portion 35c of the other light and dark burner 3 is suppressed, and the temperature of the rich flame is not lowered so much. Therefore, it is possible to effectively prevent the deep flame from being easily lifted by the recessed portions 35c of the other light and dark burners 3. Moreover, since the restriction member 8 is integrally formed by extending the claw portion 4a on the positioning member 4 _1, the number of components is not increased, it is possible to avoid an increase in cost.

DESCRIPTION OF SYMBOLS 1 ... Combustion housing, 11 ... Combustion chamber, 12 ... Supply chamber, 2 ... Partition plate, 2a ... Distribution hole, 3 ... Concentration burner, 31 ... Pale flame opening, 32 ... Blind gap, 33 ... Rich flame opening, 35 ... Wall plate, 35c ... recessed portion, 4 ₁ ... positioning member, 7 ... frame rod, 8 ... limiting member.

Claims (3)

A combustion housing, and a partition plate that divides the space in the combustion housing into a combustion chamber and an air supply chamber below the combustion chamber is provided in the combustion housing;
At the upper end, a pale flame outlet that is long in the front-and-rear direction that emits a lean air-fuel mixture with a leaner fuel concentration than the stoichiometric air-fuel ratio, and a blind gap that is located on both sides of the pale flame mouth and in which the air-fuel mixture does not jet, It is located outside the air gap in the lateral direction, and has a rich flame outlet that ejects a rich air-fuel mixture with a higher fuel concentration than the light air-fuel mixture. A plurality of light and dark burners that are higher than the upper end of the flame opening and the blind gap are arranged side by side in the combustion chamber,
A combustion apparatus in which secondary air is supplied from a supply chamber to a combustion chamber through a number of distribution holes formed in a partition plate,
In the case where the flame rod is arranged facing the upper side of the predetermined light and dark burner, and the flame rod stops detecting the flame by the flame lift at the time of lack of oxygen, the combustion is stopped.
The predetermined light and dark burner is formed in a part having a recess notched below the upper end of the other part of the wall plate in a part located directly below the frame rod of the wall plate on the laterally outer side of the rich flame mouth ,
A combustion apparatus characterized in that the height of the bottom of the recess is equal to the height of the upper end of the blind gap . A combustion apparatus according to claim 1 Symbol placement, in what are other shades burner other than the predetermined gray burner which consists of a predetermined grayscale burner and shades burner of the same model,
A combustion apparatus comprising: a restricting member that restricts the supply of secondary air to a portion where a recessed portion is formed on a wall plate on the laterally outer side of a thick flame opening of another light and dark burner. The combustion apparatus according to claim 2 , further comprising a positioning member that engages the front and rear end portions of each light and dark burner to position each light and dark burner.
A combustion apparatus, wherein the restriction member is integrally formed with a positioning member.

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