JP2008286448A - Flat gas burner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flat gas burner capable of reducing combustion noise and preventing increase in manufacturing costs. <P>SOLUTION: In this flat gas burner wherein a burner main body 1 provided with a long burner flame port 3 on its upper end portion and composed of a pair of side plates 1a, is provided with a lower mixing pipe, a distributing pipe 6 connected with the mixing pipe and extending in the longitudinal direction at an upper side of the mixing pipe, and a throttle 7 formed by narrowing a lateral width between the distributing pipe 6 and the burner flame port 3, and a straightening member 9 having a plurality of straightening vanes 10-13 laterally arranged in parallel with each other, is mounted in the burner flame port 3, the pair of straightening vanes 11, 12 positioned at a center of the lateral width of the burner flame port 3 and laterally adjacent to each other are linearly inclined in the directions to be gradually close to each other from a lower end toward an upper end. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a flat gas burner used as a heat source for a hot water supply heat source machine or the like.

  In general, in a heat source machine, a plurality of flat gas burners having an elongated flame opening at an upper end thereof are arranged in parallel in a combustion casing forcibly supplying combustion air by a combustion fan. Conventionally, this type of flat gas burner has a burner body composed of a pair of side plates facing each other in the longitudinal direction when the longitudinal direction of the flame port is the front-rear direction and the short direction of the flame port is the horizontal direction. A mixing pipe part, a distribution pipe part connected to the mixing pipe part and extending in the front-rear direction on the upper side of the mixing pipe part, and a throttle part having a narrow lateral width between the distribution pipe part and the flame port part And a rectifying member having a plurality of rectifying plates arranged in parallel in the lateral direction is mounted in the flame opening.

  The rectifying member is provided to rectify the air-fuel mixture and eject it from the flame opening. Here, when the flat gas burner is disposed in the combustion housing for forcibly supplying the combustion air by the combustion fan, turbulent flow is likely to occur due to the influence of the primary air forcibly flowing into the mixing tube portion. Therefore, in order to rectify the flow of the air-fuel mixture, the number of rectifying plates constituting the rectifying member needs to be four or more.

  By the way, as an example, in the case where the number of rectifying plates is four, each rectifying plate defines three flame opening channels. Among these, when the ejection speed of the air-fuel mixture from the upper flame outlet at the upper end of the central flame outlet channel located in the center in the lateral direction becomes slower than the ejection speed of the air-fuel mixture from the upper flame outlet at the upper end of the flame outlet channel, The flame at the mouth becomes unstable and combustion noise is likely to occur.

  Therefore, the pair of rectifying plates forming the central flame channel is bent at the midway position in the vertical direction, and the downstream gap is made narrower than the upstream gap through the bent portion, thereby the central flame outlet. An apparatus that accelerates the flow velocity of the air-fuel mixture passing through the flow path is known (see Patent Document 1).

However, when the bent portion is provided at the midway position in the vertical direction of the rectifying plate forming the central flame channel as described above, the flow direction of the air-fuel mixture is suddenly changed by the bent portion to generate a vortex. As a result, the rectifying action of the air-fuel mixture by the rectifying plate is adversely affected by the vortex and the combustion noise cannot be sufficiently reduced. Furthermore, there is a disadvantage that the flow resistance of the air-fuel mixture flowing in the flame mouth channel increases due to the vortex flow caused by the bent portion, and the flow rate of the air-fuel mixture in the central flame channel can not be sufficiently accelerated. In addition, since the bent portion extending in the front-rear direction of the current plate is provided, the number of processing steps for the current plate is increased, resulting in an increase in manufacturing cost.
Japanese Unexamined Patent Publication No. 2000-193213 (FIG. 1)

  This invention makes it the subject to provide the flat gas burner which can reduce a combustion noise and can prevent the increase in manufacturing cost in view of the above point.

  In order to achieve such an object, the present invention has an elongated flame mouth portion opening upward at the upper end portion, the longitudinal direction of the flame mouth portion being the front-rear direction, and the short direction of the flame mouth portion being the lateral direction. A burner body composed of a pair of side plates facing each other in the lateral direction, a lower mixing tube portion, a distribution tube portion connected to the mixing tube portion and extending in the front-rear direction above the mixing tube portion, and a distribution tube portion A flat gas burner in which a narrowing portion having a narrow lateral width is formed between the flaming portion and a rectifying member having a plurality of rectifying plates arranged side by side in the flaming portion. The pair of rectifying plates adjacent to each other in the lateral direction located in the center of the lateral width of the portion is provided so as to be inclined linearly in a direction gradually approaching from the lower end to the upper end.

  According to the present invention, since the pair of current plates adjacent to each other in the lateral direction is inclined at the center of the width of the flame opening, the horizontal distance between both current plates is lower than the lower end (upstream end). Narrow at the upper end (downstream end). Thereby, the flow velocity of the air-fuel mixture in the flame opening channel formed by both rectifying plates can be accelerated. Since both the rectifying plates are linearly inclined, the air-fuel mixture can be smoothly accelerated without forming a vortex in the air-fuel mixture in the flame channel by the both rectifying plates. In addition, since it is only necessary to incline both the current plates, the structure becomes simple and the manufacturing cost can be kept low.

  By the way, it is also possible to provide the aperture portion at a position offset to one side in the lateral direction. However, in this case, the burner body has an asymmetric shape with respect to the center of the lateral width, and the production becomes troublesome. Therefore, it is desirable that the narrowed portion is formed so that the center of the width thereof coincides with the center of the width of the burner body. In this case, it is preferable that the pair of inclined rectifying plates are provided so as to oppose each other in the lateral direction via a center line extending upward through the lateral width center of the throttle portion. By doing so, the lower end of the flame opening channel by both rectifying plates is located immediately above the restricting part, so that a sufficient amount of air-fuel mixture from the restricting part can be smoothly guided between the two rectifying plates, which is unnecessary. Turbulent flow can be prevented and combustion noise can be reduced.

  Furthermore, in this case, by providing a pair of inclined current plates symmetrically with respect to the center line, symmetry about the horizontal center of the burner body is ensured, and the amount of air-fuel mixture ejected from the flame port Can be made uniform in the horizontal distribution. Thereby, a flame can be stabilized and a combustion noise can be reduced reliably.

  In the present invention, the pair of inclined rectifying plates are characterized in that extended lines extending upward from the upper end along the inclined direction intersect with each other at an angle of 0.3 ° to 1 °. The present inventor has conducted various tests in order to find a good inclination angle of the pair of rectifying plates. As a result, when the angle between the extension lines is smaller than 0.3 °, the air-fuel mixture passing between the rectifying plates is obtained. It was found that sufficient acceleration could not be obtained in the air-fuel mixture due to the rapid focusing of the air-fuel mixture at the upper end sides of both rectifying plates even if it was larger than 1 °. Furthermore, when the angle at which the extension lines intersect is greater than 1 °, the lower ends of both rectifying plates are relatively large and spread in the lateral direction, making it difficult to accommodate in the burner body. Based on these findings, the angle at which the extension lines cross each other is set to 0.3 ° to 1 °, the rectifying plate is made compact, and the mixture is sufficiently accelerated.

  Further, in the present invention, another rectifying plate is provided on each laterally outer side of the pair of inclined rectifying plates so as to face each of the inclined rectifying plates in parallel. Since the other rectifying plate is provided in parallel to the laterally outer side of the inclined rectifying plate, the interval between the inclined rectifying plate and the other rectifying plate outside thereof is the same on the lower end side and the upper end side, The passing air-fuel mixture is not accelerated. As a result, the speed of the air-fuel mixture ejected from both sides becomes slower than the speed of the air-fuel mixture ejected from between the two rectifying plates that are inclined, so that the flame at the flame opening is stabilized and the generation of combustion noise is reduced.

  An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a lean combustion type flat gas burner used as a heat source of a hot water supply heat source machine. Although not shown, the heat source device includes a combustion casing that forcibly supplies combustion air by a combustion fan, and a plurality of flat gas burners are arranged in parallel in the combustion casing.

  The flat gas burner shown in FIG. 1 includes a burner body 1 and a burner cap 2 that covers the upper part of the burner body 1. At the upper end of the burner body 1, an elongated flame opening 3 that opens upward is formed. Also, the burner cap 2 forms slit-shaped sleeve flame openings 4 located on both sides of the flame opening 3. Then, an air-fuel mixture having a leaner fuel ratio than the stoichiometric air-fuel ratio (air-rich air-fuel mixture) is ejected from the flame port 3, and an air-fuel mixture having a higher fuel ratio than the stoichiometric air-fuel ratio (gas-rich air-fuel mixture) is The generation of NOx can be reduced by ejecting from 4 and performing so-called light and dark combustion.

  Hereinafter, the configuration of the flat gas burner will be described with the longitudinal direction of the flame port 3 as the front-rear direction and the short direction of the flame port 3 as the horizontal direction. As shown in FIGS. 2 and 3, the burner body 1 is composed of a pair of side plates 1a facing each other in the lateral direction. The both side plates 1a are formed of a single continuous plate, and the burner body 1 is formed by bending the plates into a palm-joined state along a fold line that becomes the lower edge of the burner body 1. Then, by pressing each side plate 1 a, the burner body 1 is connected to the upper end flame port portion 3, the lower mixing tube portion 5, and the mixing tube portion 5, and in the front-rear direction above the mixing tube portion 5. An extending distribution tube portion 6 and a narrowed portion 7 having a narrow lateral width between the distribution tube portion 6 and the flame port portion 3 are formed.

  The mixing tube portion 5 extends forward from an opening end 5 a located at the lower rear edge of the burner body 1, and its front end portion is bent upward and communicates with the distribution tube portion 6. In addition, at the rear part of the burner main body 1, a mixing pipe part 8 for a sleeve fire is formed between the mixing pipe part 5 and the distribution pipe part 6. The mixing tube portion 8 is terminated by slightly extending forward from an opening end 8a located at the rear edge of the burner body 1, and a plurality of vent holes 8b are formed on the side surface of the front portion. Fuel gas is supplied to the mixing pipe portions 5 and 8 from different gas nozzles (not shown) facing the open ends 5a and 8a. At the same time, by supplying air (primary air) from the combustion fan, the fuel gas and the primary air are mixed in the mixing pipe portions 5 and 8 to generate an air-fuel mixture.

  The opening end 5a of the mixing tube portion 5 is formed to be relatively large. Therefore, the inflow amount of primary air increases in the mixing pipe unit 5 and an air-rich air-fuel mixture is generated. On the other hand, the opening end 8a of the sleeve-fire mixing tube portion 8 is formed to be relatively small. Therefore, in the mixing pipe portion 8, the amount of primary air flowing in is reduced, and a gas rich mixture is generated.

  As shown in FIGS. 1 and 3, the burner cap 2 includes a pair of side plates 2 a that are placed on the outside of the pair of side plates 1 a of the burner body 1, and a plurality of bridge portions 2 b that connect the side plates 2 a at their upper edges. It consists of Between the side plate 1a of the burner main body 1 and the side plate 2a of the burner cap 2, the sleeve flame opening 4 at the upper end and the outer side of the burner main body 1 through the vent hole 8b from the mixing tube portion 8 for the sleeve fire. A passage for guiding the air-fuel mixture flowing out to the sleeve flame opening 4 is formed.

  The side plate 2a of the burner cap 2 is in contact with the outer surface of the intermediate portion in the front-rear direction of the distribution pipe portion 6 of the burner body 1, and has a recess 2c that distributes the flow of the air-fuel mixture from the vent hole 8a in the front-rear direction. A plurality of longitudinally recessed portions 2d are formed in contact with the outer surface of the flame mouth portion 3 of the burner body 1 and partition the sleeve flame mouth portion 4 into a plurality of front and rear areas.

  A rectifying member 9 is mounted in the flame opening 3 of the burner body 1. As shown in FIG. 3, the rectifying member 9 has four rectifying plates 10, 11, 12, 13 arranged side by side in the lateral direction, and a horizontal width is provided between the rectifying plates 10, 11, 12, 13. Narrow flame channel 14, 15, 16 is defined. As shown in FIG. 2, these rectifying plates 10, 11, 12, and 13 are abutted and polymerized at a plurality of abutting portions 17 at the front and back of the rectifying plates 10, 11, 12, and 13. Divided into multiple areas. As shown in FIG. 1, the bridge portion 2 b of the burner cap 2 is positioned directly above the contact portion 17. As shown in FIGS. 2 and 3, the flame opening 3 of the burner body 1 is formed with a narrowed portion 3 a that is positioned in the middle in the vertical direction and sandwiches the rectifying member 9 from both lateral sides. . As a result, a blind gap 3b is formed between the portion of the side plate 1a on the upper side of the narrowed portion 3a and the outermost rectifying plates 10 and 13 (other rectifying plates) of the rectifying member 9 so that no air-fuel mixture flows.

  The air-fuel mixture generated in the mixing tube portion 5 of the burner body 1 flows to the flame opening portion 3 through the distribution tube portion 6 and the throttle portion 7, and is connected between the four rectifying plates 10, 11, 12, and 13. It is jetted above the flame port portion 3 through the two flame port channels 14, 15, 16 and burned. The lateral width of the throttle portion 7 gradually increases from the front portion toward the rear, and the flow rate distribution in the front-rear direction of the air-fuel mixture flowing into the flame port portion 3 is equalized. In addition, the narrowed portion 7 is formed so that the center of its width coincides with the center of the width of the burner body 1.

  As shown in FIG. 3, among the four rectifying plates 10, 11, 12, and 13 of the rectifying member 9, the adjacent rectifying plates 11 and 12 that are located adjacent to each other at the center of the lateral width of the flame port 3 are the lateral width of the throttle unit 7. Opposing through a center line x extending upward through the center, the central flame channel 15 is formed directly above the throttle portion 7. The rectifying plates 11 and 12 at the central position are linearly inclined in a direction of gradually approaching toward the upper end. The other rectifying plates 10 and 13 located on the outermost side (both outer sides of the rectifying plates 11 and 12 at the central position) are provided in parallel and inclined along the rectifying plates 11 and 12 at the central position. Outer flame opening channels 14 and 16 are formed along both outer sides of the mouth channel 15.

  More specifically, as shown in FIG. 3, both the rectifying plates 11 and 12 at the central position are symmetrical with respect to each other via the center line x, and the inclination of both the rectifying plates 11 and 12 is inclined in the direction of inclination from the upper end thereof. The angle θ at which the extended lines r extending upward along the lines intersect is set to be 0.3 ° to 1 °. In FIG. 3, for convenience of explanation, the slopes of both rectifying plates 11 and 12 are exaggerated. Accordingly, it is assumed that the illustrated angle θ exceeds 1 °, but is actually within a range of 0.3 ° to 1 °. Thereby, the space | interval dimension of the upper end (downstream end of the central flame flow path 15) of both the baffle plates 11 and 12 of a center position is narrower than the space | interval dimension of a lower end (upstream end of the central flame flow path 15). . Further, the outermost rectifying plates 10 and 13 are parallel to the rectifying plates 11 and 12 at the central position adjacent to each other, so that the upper end (the downstream end of the outer flame channel 14 and 16) and the lower end ( The same interval dimension is set at the upstream end of the outer flame opening channels 14 and 16.

  The rectifying plates 10, 11, 12, and 13 constitute the rectifying member 9 in a state of being connected to each other. That is, as shown in FIG. 4A, in the state of being punched from a metal plate material, both the rectifying plates 11 and 12 at the central position are connected to each other via a pair of front and rear connecting portions 18, and each rectifying plate is The rectifying plates 10 and 13 are connected to the outer sides of 11 and 12 via a plurality of connecting portions 19, respectively. A raised portion 20 serving as a contact portion 17 is formed on the upper end side of both the rectifying plates 11 and 12 at the center position, and as shown in FIG. A protruding portion 21 that abuts against each other and inclines between the rectifying plates 11 and 12 is formed to protrude in the opposing direction. Further, on the upper end side of the outer rectifying plates 10, 13, a raised portion 22 that is in contact with each rectifying plate 11, 12 and becomes the abutting portion 17 is formed, and on the lower end side, each rectifying plate 11, The ridges 23 are formed so as to be parallel to the rectifying plates 11 and 12 adjacent to the rectifying plates 10 and 13 in contact with the rectifying plates 10 and 13. When the rectifying member 9 is formed, as shown in FIG. 4B, the connecting portion 18 between the rectifying plates 11 and 12 at the central position is folded in a mountain fold, and the outer rectifying plates 10 and 13 are connected to the connecting portion. Fold it into valley folds through 19. Thereby, as shown in FIG.4 (c), the rectification | straightening member 9 formed in the assembly | attachment state is formed. At this time, as shown in FIG. 5, both the rectifying plates 11 and 12 at the center are inclined and face each other due to the abutment of the protruding portions 21. In addition, the inclination state of both the baffle plates 11 and 12 of a center position can be formed very easily by presetting the protrusion amount of the protrusion part 21 so that the above-mentioned inclination angle (theta) may be obtained. Further, the rectifying plates 10 and 13 outside the respective rectifying plates 11 and 12 are opposed to the rectifying plates 11 and 12 in parallel by a raised portion 22 serving as the contact portion 17 and a raised portion 23 below the raised portion 22. And the rectification | straightening member 9 used as the assembly | attachment state shown in FIG.4 (c) is mounted | worn in the flame opening part 3, as shown in FIG.

  When the current plates 10, 11, 12, 13 are arranged as described above, the air-fuel mixture from the throttle portion 7 smoothly flows through the central flame channel 15 and the outer flame channels 14, 16, and is thereby rectified. The state is rectified by the plates 10, 11, 12, and 13. At this time, the air-fuel mixture flowing in the central flame channel 15 is accelerated by the inclination of the both rectifying plates 11 and 12 at the central position and the interval between the central flame channels 15 becoming narrower toward the downstream side. . On the other hand, the air-fuel mixture flowing through the outer flame channel 14 and 16 is not accelerated because the distance between the upstream side and the downstream side does not change. As a result, the flow rate of the air-fuel mixture ejected from the upper end of the central flame channel 15 becomes faster than the flow rate of the air-fuel mixture ejected from the upper ends of the outer flame port channels 14 and 16. As a result, the flame formed in the flame opening 3 is larger in the central part in the lateral direction of the flame opening 3 than both sides thereof, so that a stable flame that hardly vibrates and burns is formed.

  Although the embodiment in which the number of the rectifying plates 10, 11, 12, 13 constituting the rectifying member 9 is four has been described above, other than that, although not shown, the number of rectifying plates may be five or more. . When the number of current plates is an odd number, a single current plate is positioned along the center line x of the diaphragm 7, and a pair of current plates opposite to each other are gradually approached from the lower end to the upper end. What is necessary is just to incline linearly in the direction to do.

  Moreover, although the flat burner of the said embodiment is a concentration combustion type burner provided with the burner cap 2, this invention is applicable similarly to the flat gas burner which does not have the burner cap 2, and is not a concentration combustion type.

The perspective view which shows the flat gas burner of one Embodiment of this invention. The perspective view which shows a burner main body. III-III sectional view explanatory drawing of FIG. (A) is an expanded view of a rectification member, (b) is explanatory drawing which shows the assembly process of a rectification member, (c) is explanatory explanatory perspective view of the assembly state of a rectification member. VV sectional view explanatory drawing in FIG.4 (c).

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Burner main body, 1a ... Side plate, 3 ... Flame port part, 5 ... Mixing pipe part, 6 ... Distribution pipe part, 7 ... Restriction part, 9 ... Rectification member 10, 11, 12, 13 ... Rectification board, 11, 12 ... A pair of inclined current plates, 10, 13 ... Outer current plates (other current plates), x ... Center line, θ ... Angle.

Claims (5)

The upper end has an elongated flame opening that opens upward, and consists of a pair of side plates facing each other in the lateral direction, with the longitudinal direction of the flame opening being the front-rear direction and the short direction of the flame opening being the lateral direction. The burner body is connected to the lower mixing tube, the distribution tube that extends in the front-rear direction on the upper side of the mixing tube, and the width between the distribution tube and the flame opening is reduced. In the flat gas burner in which a throttle part is formed, and a rectifying member having a plurality of rectifying plates arranged in parallel in the lateral direction is mounted in the flame opening part,
A flat gas burner characterized in that a pair of rectifying plates adjacent to each other in the lateral direction located in the lateral width center of the flame opening portion are linearly inclined in a direction gradually approaching from the lower end to the upper end. The throttle part is formed such that the center of the width of the throttle part coincides with the center of the width of the burner body,
2. The flat gas burner according to claim 1, wherein the pair of rectifying plates that are inclined face each other in a lateral direction through a center line that extends upward through the lateral width center of the throttle portion.   The flat gas burner according to claim 2, wherein the pair of inclined current plates are provided symmetrically with respect to the center line.   4. The pair of inclined current plates, wherein extension lines extending upward along the inclined direction from the upper ends thereof intersect at an angle of 0.3 [deg.] To 1 [deg.]. The flat gas burner described.   5. The rectifying plate according to claim 1, further comprising a rectifying plate arranged parallel to the rectifying plate that is inclined in parallel with each of the inclined rectifying plates. The flat gas burner described.

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