JP2013213623A - Metal knit burner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal knit burner having a high turndown ratio.SOLUTION: A metal knit burner includes a cylindrical member, a metal knit attached so as to cover an end of the cylindrical member, and a support member arranged in the cylindrical member so as to support the metal knit. The metal knit includes a recessed part which recesses inward from an edge surface of the cylindrical member. The support member includes a plurality of plate members radially arranged from a center axis of the cylindrical member, and the metal knit is supported by oblique sides of the plate members.

Description

  The present invention relates to a gas burner device used in a gas combustion device, and more particularly to a metal knit burner for burning a premixed gas.

  As a burner for burning the premixed gas, a so-called metal knit burner using a metal knit for the burner element is used. The metal knit is formed by knitting heat-resistant metal fibers into a knit shape. Compared to conventional ceramic burners, the metal knit burner can easily change the shape and dimensions of the burner element, shorten the preheating time and cooling time, reduce the turbulence and pressure loss of the premixed gas, etc. Excellent in terms. Accordingly, metal knit burners are used in gas combustion apparatuses in various industrial fields.

  Patent Document 1 describes an example in which a metal knit burner is used in a combustion apparatus for heating a ladle. In this example, a hemispherical or conical metal knit burner element is used.

JP 2001-235107 A

  One of the indexes representing the performance of the gas burner is the turndown ratio. The turndown ratio is the ratio between the maximum (rated) fuel flow rate per burner and the minimum fuel flow rate, and is also called the burner load adjustment range. The larger the turndown ratio, the wider the adjustment range of the flow rate (load). Therefore, it is suitable for an application where the fluctuation of the combustion load is large. Therefore, the combustion apparatus provided with the burner with a large turndown ratio is excellent in economic efficiency and can reduce fuel waste.

  In recent years, a burner apparatus having a large turndown ratio has been demanded due to a demand for energy saving. In the conventional premixing type metal knit burner, it is difficult to increase the turndown ratio.

  An object of the present invention is to provide a metal knit burner having a large turndown ratio.

  According to the present invention, the metal knit burner includes a cylindrical member, a metal knit mounted so as to cover the tip of the cylindrical member, and a support provided inside the cylindrical member to support the metal knit. And the metal knit has a recess recessed inward from the tip surface of the cylindrical member.

  According to this embodiment, the tubular member is provided with a first tubular member, and a spark plug is housed in the first tubular member, and the tip of the spark plug is exposed by the metal knit. Good.

  According to this embodiment, the first tubular member may be disposed on the opposite side of the flame formed by the metal knit and exposed to the flow of premixed gas supplied to the metal knit.

  According to this embodiment, a hole is provided in the first tubular member, and the premixed gas that has flowed into the first tubular member via the hole passes around the spark plug and burns the metal knit. May be discharged to the side.

According to the present embodiment, the tubular member is provided with a second tubular member on the opposite side of the combustion side of the metal knit, and a flame detector is accommodated in the second tubular member, The second tubular member is exposed to a flow of premixed gas supplied to the metal knit;
A hole is provided in the second tubular member, and the premixed gas flowing into the second tubular member through the hole passes through the flame detector and is discharged to the combustion side of the metal knit. Good.

  According to this embodiment, the support member may have a plurality of plate members arranged radially from the central axis of the cylindrical member, and the metal knit may be supported by the oblique sides of the plate member.

  According to this embodiment, the recess may have a quadrangular pyramid recess shape.

  According to the present embodiment, when the inclination angle of the recess with respect to a plane orthogonal to the central axis of the cylindrical member is θ, the inclination angle may be θ = ± 30 °.

  According to the present invention, a combustion apparatus supplies any of the metal knit burners described above, a mixer that mixes air and combustion gas to generate a premixed gas, and supplies the premixed gas to the metal knit burner. And a fan.

  According to the present invention, a combustion apparatus system includes a combustion apparatus including a metal knit burner and a mixer that supplies a premixed gas to the metal knit burner, an air supply system that supplies air to the mixer, and the mixing A fuel gas supply system for supplying fuel gas to the machine, the metal knit burner supporting a cylindrical member, a metal knit mounted so as to cover a tip of the cylindrical member, and the metal knit And a support member provided inside the cylindrical member, and the metal knit has a recess recessed inward from a tip surface of the cylindrical member.

  According to the present invention, a metal knit burner having a large turndown ratio can be provided. Furthermore, according to the present invention, it is possible from combustion like a premixed burner to surface combustion on the combustion surface.

FIG. 1A is an explanatory view illustrating the appearance of the metal knit burner according to the present embodiment. FIG. 1B is an explanatory view illustrating the internal structure of the metal knit burner according to the present embodiment. FIG. 2A is an explanatory view illustrating an example of a plate material constituting the support member of the metal knit burner according to the present embodiment. FIG. 2B is an explanatory diagram for explaining the positional relationship between the concave portion of the metal knit of the metal knit burner according to the present embodiment and the tubular member. FIG. 3A is an explanatory diagram for explaining the state of the flame when the combustion amount is relatively large in the metal knit burner of the present embodiment. FIG. 3B is an explanatory view illustrating a flame state when the combustion amount is relatively small in the metal knit burner of the present embodiment. FIG. 4 is an explanatory view illustrating the main part of the combustion apparatus using the metal knit burner of the present embodiment. FIG. 5 is an explanatory view illustrating an example of the structure of the spark plug inserted into the tubular member of the metal knit burner according to the present embodiment. FIG. 6A is an explanatory diagram illustrating an example of the shape of the concave portion of the metal knit burner according to the present embodiment. FIG. 6B is an explanatory diagram illustrating an example of the shape of the concave portion of the metal knit burner according to the present embodiment. FIG. 6C is an explanatory diagram illustrating an example of the shape of the recess of the metal knit burner according to the present embodiment. FIG. 6D is an explanatory diagram illustrating an example of the shape of the recess of the metal knit burner according to the present embodiment. FIG. 6E is an explanatory view illustrating an example of the shape of the concave portion of the metal knit burner according to the present embodiment.

  Hereinafter, embodiments of a metal knit burner according to the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1A shows the appearance of the metal knit burner according to this embodiment, and FIG. 1B shows the internal structure of the metal knit burner according to this embodiment. As shown in FIG. 1A, the metal knit burner according to the present embodiment includes a tubular member 12 and a metal knit 10 that is a burner element attached to the tip end surface thereof. The cylindrical member 12 preferably has a circular cross section, but may be an elliptical cross section or a polygonal cross section. The metal knit 10 is recessed inward at the distal end surface of the cylindrical member 12 to form a recess. In the conventional metal knit burner, the metal knit has a shape that swells outward from the tip surface of the burner, but in the present embodiment, conversely, it is recessed inward from the tip surface of the burner. The recess formed by the metal knit may be a quadrangular pyramid shape, but may be a polygonal pyramid shape such as a triangular pyramid shape, and may be a conical shape, a hemispherical shape, or a semi-elliptical spherical shape. . Further, the inner surface of the concave portion may be configured to be recessed so as to be narrowed stepwise.

  The metal knit 10 is provided with the tips of tubular members 16 and 18. In the illustrated example, the tip of the first tubular member 16 is exposed from the hole provided in the metal knit 10, but the tip of the second tubular member 18 is not exposed. A spark plug is inserted into the first tubular member 16, and the tip thereof is exposed from the hole of the metal knit 10. A flame detector is inserted into the second tubular member 18. Ultravision may be used as a flame detector. Ultravision is a sensor that detects ultraviolet rays in a flame, and is widely used as a safety device for combustion equipment such as boilers.

  The metal knit 10 is a knitted heat-resistant metal fiber knitted. As the heat-resistant metal fiber, for example, an iron alloy containing about 20 to 22% of chromium known as Fecralloy (registered trademark) may be used.

  FIG. 1B shows a structure when the metal knit 10 and the cylindrical member 12 are removed from the metal knit burner shown in FIG. 1A. The cylindrical member 12 is indicated by a two-dot chain line. Inside the tubular member 12, a metal knit support member 14 is provided. In the present embodiment, the support member 14 includes a plurality of plate members, for example, four plate members 14A, 14B, 14C, and 14D. The four plate members are arranged so as to extend radially from the central axis of the cylindrical member 12. The shape of the plate material corresponds to the shape of the recess formed by metal knit. On the support member 14, a holding member (not shown) that holds the concave portion of the metal knit is disposed. The holding member has a shape corresponding to the shape of the concave portion of the metal knit, and has a rough gap so that the premixed gas can pass therethrough. An expanded metal may be used as the holding member.

  Two tubular members 16 and 18 are provided inside the tubular member 12. The distal ends of the two tubular members 16 and 18 extend to the concave portion of the metal knit 10. A spark plug is inserted into the first tubular member 16, and a flame detector is inserted into the second tubular member 18. The cylindrical member 12, the support member 14, and the tubular members 16, 18 may be made of stainless steel.

  In the present embodiment, as shown in the drawing, the tubular members 16 and 18 are disposed on the opposite side of the metal knit 10 from the combustion side, that is, on the supply side of the premixed gas. Therefore, the spark plug and the flame detector in the tubular members 16 and 18 are not heated to a high temperature by the flame formed by the metal knit 10.

  FIG. 2A shows an example of a plate material constituting the support member 14. The plate material 14A has a right trapezoidal shape formed by obliquely cutting one side of a rectangular plate material. The metal knit 10 is supported by the oblique side 14a of the right trapezoid. An inclination angle of the hypotenuse 14a with respect to a plane orthogonal to the central axis zz of the cylindrical member 12 is defined as θ (theta). θ may be 10 ° to 60 °, and preferably θ = 30 ± 10 °. When the combustion surface of the metal knit 10 is hemispherical, the hypotenuse 14a is a curved surface.

  FIG. 2B shows the positional relationship between the concave portion of the metal knit 10 and the tubular members 16 and 18. An inclination angle of the metal knit 10 with respect to a plane orthogonal to the central axis zz of the cylindrical member 12 is defined as θ (theta). The inclination angle of the central axes PP, QQ of the tubular members 16, 18 with respect to the central axis zz of the tubular member 12 is defined as θ1. The inclination angle θ1 may be the same as or smaller than the inclination angle θ of the metal knit 10. That is, θ1 ≦ θ may be satisfied.

  With reference to FIG. 3A and 3B, the combustion function in the metal knit burner of this embodiment is demonstrated. 3A and 3B schematically illustrate a cross-sectional configuration obtained by cutting the metal knit burner of the present embodiment along a plane passing through the central axis. The metal knit 10 has a recessed portion 10 </ b> A that is recessed inside the tubular member 12 and an attachment portion 10 </ b> B that extends to the outer edge of the tubular member 12.

  FIG. 3A shows the state of the flame when the combustion amount is relatively large. The premixed gas 101 supplied via the cylindrical member 12 is ignited by a spark plug (not shown), and a combustion surface 102 is generated slightly outward from the surface of the recess 10A of the metal knit 10. When the amount of fuel gas is large, air is insufficient, and a part of the mixed gas that has passed through the central portion of the concave portion of the metal knit 10 becomes unburned gas 103 as shown in the figure. However, the unburned gas 103 is combusted by the combustion surface 102 formed in a region near the outer edge of the recess 10A of the metal knit 10, and becomes a front flame 104 and completely combusted. Therefore, combustion like a premixed burner with a pilot burner is possible. This is because the flame on the combustion surface 102 is oriented in the direction of the central axis, so that high flame holding properties are obtained.

  FIG. 3B shows the state of the flame when the amount of combustion is relatively small. When air is excessive with respect to the fuel gas, surplus air 105 is generated. In such a case, with the conventional burner, the flame may become unstable and misfire may occur depending on the usage environment. However, in the metal knit burner according to the present embodiment, the combustion surface 102 is formed slightly outward from the surface of the concave portion 10A of the metal knit 10, and this combustion surface 102 faces the central axis direction. Becomes higher. Therefore, when the amount of fuel gas is small, combustion on the surface of the recess 10A of the metal knit 10 is possible. That is, according to the present embodiment, it is possible from combustion like a gun burner to surface combustion in which the combustion surface is heated red.

  With reference to FIG. 4, the principal part of the combustion apparatus using the metal knit burner of this embodiment is demonstrated. The combustion apparatus has a metal knit burner 1, a fan 25 and a mixer 26. In the present embodiment, the mixer 26 is a Venturi mixer. The metal knit burner 1 includes a tubular member 12, a holding member 15, a metal knit 10, and two tubular members 16 and 18. Here, illustration of the support member 14 (FIG. 1B) is omitted.

  A spark plug 21 is inserted into the first tubular member 16. The tip of the first tubular member 16 is exposed to the outside of the metal knit 10. The tip of the spark plug 21 is disposed close to the outer surface of the metal knit 10. The tip of the second tubular member 18 is disposed inside the metal knit 10 and is not exposed. A flame detector 22 is inserted into the second tubular member 18. Ultravision may be used as the flame detector 22. An ultravision adapter may be attached between the inner end of the second tubular member 18 and the ultravision. In the adapter for ultra vision, a circular glass plate is arranged so as to be orthogonal to the axial direction. Ultravision is blocked from the internal space of the second tubular member 18 by the circular glass plate.

  The air supplied via the air supply pipe 27 and the gas supplied via the gas supply pipe 28 are mixed by the mixer 26 to generate a premixed gas. The premixed gas is supplied to the metal knit 10 of the metal knit burner via the fan 25 provided in the premixed gas supply pipe 24 and ignited by the spark plug 21. The flame 104 formed by the metal knit 10 is always observed by the flame detector 22.

  In the present embodiment, the tubular members 16 and 18 are arranged inside the flame 104 of the metal knit 10, that is, upstream of the premixed gas as shown in the drawing. Further, the tubular members 16 and 18 are exposed to the premixed gas supplied via the premixed gas supply pipe 24. Therefore, the spark plug 21 and the flame detector 22 are not heated by the flame 104 formed by the metal knit 10 and become high temperature.

  With reference to FIG. 5, the example of the structure of the spark plug 21 inserted in the 1st tubular member 16 is demonstrated. The spark plug 21 includes an electrode 211 at the front end, an insulator 212, and a terminal (terminal) 213 at the rear end. The electrode 211 has a center electrode 211A and a side electrode 211B.

  The distal end of the tubular member 16 is open to the recess of the metal knit 10. A premixed gas inflow hole 16 a is formed on the side surface of the tubular member 16. The premixed gas supplied via the premixed gas supply pipe 24 flows into the tubular member 16 through the premixed gas inflow hole 16a of the tubular member 16 as shown by an arrow, and is ignited. The metal knit 10 is discharged to the outside through the periphery of the plug 21. Thus, in this embodiment, since the spark plug 21 is cooled by the premixed gas, it is prevented that the spark plug 21 becomes excessively hot.

  In the present embodiment, since the tip of the spark plug 21 is disposed at a position close to the combustion surface of the metal knit 10, the pilot system of the spark plug 21 can be omitted.

  The second tubular member 18 has the same structure, and the flame detector 22 inserted therein is cooled by the premixed gas.

  6A to 6D show examples of cross-sectional shapes of the concave portions of the metal knit of the metal knit burner according to the present embodiment. FIG. 6A shows a cross-sectional shape when the concave portion has a pyramid or conical shape. FIG. 6B shows a cross-sectional shape in the example of FIG. 6A when the bottom surface of the recess is flat. FIG. 6C shows a cross-sectional shape in the case where the concave portion has a shape obtained by combining a plurality of pyramids or conical shapes. FIG. 6D shows a cross-sectional shape when the concave portion has a hemispherical shape or a semi-elliptical spherical shape. FIG. 6E shows a cross-sectional shape when the concave portion combines a plurality of curved surfaces in the example of FIG. 6D.

  Although the combustion apparatus provided with one metal knit burner has been described in the above example, a plurality of small metal knit burners may be bundled to form one burner.

  Although the metal knit burner according to the present embodiment has been described above, these are merely examples and do not limit the scope of the present invention. Additions, deletions, changes, improvements, and the like that can be easily made by those skilled in the art with respect to the present embodiment are within the scope of the present invention. The technical scope of the present invention is defined by the appended claims.

DESCRIPTION OF SYMBOLS 1 ... Metal knit burner, 10 ... Metal knit, 10A ... Recessed part, 10B ... Mounting part, 12 ... Cylindrical member, 14 ... Support member, 14A-14D ... Plate material, 14a ... Oblique side, 15 ... Holding member, 16 ... Tubular member 16a ... Premixed gas inflow hole, 18 ... Tubular member, 21 ... Spark plug, 22 ... Flame detector, 24 ... Premixed gas supply pipe, 25 ... Fan, 26 ... Mixer, 27 ... Air supply pipe, 28 ... 101 ... Premixed gas, 102 ... Combustion surface, 103 ... Unburned gas, 104 ... Flame, 105 ... Excess air, 211 ... Electrode, 211A ... Central electrode, 211B ... Side electrode, 212 ... Insulator, 213 …Terminal

Claims (10)

In a metal knit burner having a cylindrical member, a metal knit mounted so as to cover the tip of the cylindrical member, and a support member provided inside the cylindrical member to support the metal knit ,
The metal knit burner is characterized in that the metal knit has a recess recessed inward from the tip end surface of the cylindrical member. In the metal knit burner according to claim 1,
The tubular member is provided with a first tubular member, an ignition plug is accommodated in the first tubular member, and the tip of the ignition plug is exposed by the metal knit. Metal knit burner. In the metal knit burner according to claim 2,
The first tubular member is disposed on the opposite side of the flame formed by the metal knit, and is exposed to the flow of a premixed gas supplied to the metal knit. In the metal knit burner according to claim 2,
A hole is provided in the first tubular member, and the premixed gas that has flowed into the first tubular member through the hole passes through the periphery of the spark plug and is discharged to the combustion side of the metal knit. Metal knit burner characterized by In the metal knit burner according to claim 1,
The tubular member is provided with a second tubular member on the opposite side to the combustion side of the metal knit, and a flame detector is accommodated in the second tubular member, and the second tubular member Is exposed to the flow of premixed gas supplied to the metal knit,
A hole is provided in the second tubular member, and the premixed gas flowing into the second tubular member through the hole passes through the flame detector and is discharged to the combustion side of the metal knit. This is a metal knit burner. In the metal knit burner according to claim 1,
The metal knit burner, wherein the support member includes a plurality of plate members arranged radially from a central axis of the cylindrical member, and the metal knit is supported by the oblique sides of the plate member. In the metal knit burner according to claim 1,
The metal knit burner, wherein the recess has a quadrangular pyramid recess shape. In the metal knit burner according to claim 1,
A metal knit burner, wherein an inclination angle of the recess with respect to a plane orthogonal to the central axis of the cylindrical member is θ, θ = ± 30 °.   A metal knit burner according to any one of claims 1 to 8, a mixer for mixing air and combustion gas to generate a premixed gas, and a fan for supplying the premixed gas to the metal knit burner. And a combustion apparatus. Combustion device comprising a metal knit burner and a mixer for supplying premixed gas to the metal knit burner, an air supply system for supplying air to the mixer, and a fuel gas supply for supplying fuel gas to the mixer A combustion system comprising:
The metal knit burner is
A cylindrical member, a metal knit mounted so as to cover the tip of the cylindrical member, and a support member provided inside the cylindrical member to support the metal knit,
The said metal knit has a recessed part hollow inside the front end surface of the said cylindrical member, The combustion system characterized by the above-mentioned.

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