JP2000337613A - Burner generating hot air - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress generation of NOx and unburnt components while reducing the resistance in a duct and the manufacturing cost by forming a concave combusting part of knit-like heat resistant metallic fibers at the forward end of a premixed gas supply pipe. SOLUTION: The burner 1 generating hot air has a concave combusting part 4 formed of knit-like heat resistant metallic fibers 3 at the forward end of a premixed gas supply pipe 2. The knit-like heat resistant metallic fibers 3 are produced by knitting or weaving metallic fibers. It is commercially available as a metal fiber knit, for example. Although a conical combusting part 4 is shown, various profiles can be employed. The combusting part 4 is obtained by forming a mesh support 5 of specified shape from an expand metal, or the like, and jointing heat resistant metallic fibers 3 thereto by welding. The burner 1 is installed in a duct through which fluid to be heated, e.g. air, flows.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot-air generating burner.

[0002]

2. Description of the Related Art A hot air generating burner used in a hot air generating furnace, a deodorizing furnace, a drying furnace, etc. is installed in a duct such as a duct burner or an air heat burner in which air or the like flows, and is burned. Or a hot air burner such as an EXAS air burner that generates hot air by combustion with a high excess air ratio. A typical structure of such a hot-air generating burner is shown in FIGS.

In this hot-air generating burner, a wedge-shaped baffle plate c having a plurality of baffle holes b is installed in front of a wind box a, and fuel gas is blown out from a base of the baffle plate c and combustion air is blown out. Is used to blow out from the outside of the baffle plate c to the inside of the wedge through the baffle port b, and is installed and used in a duct d of a fluid to be heated such as air. In the burner having this configuration, the fuel gas ejected from the base of the baffle plate c is sequentially mixed with the air jet flowing in from the baffle port b and burns, that is, the step combustion by the premixing method is realized. .

[0004]

However, such a conventional representative hot-air generating burner has the following problems. a. In order to realize the staged combustion by the premixing method, the structure is complicated and the production cost is high. b. Since the wind box portion of the burner is large, if it is installed in a duct, it takes up space and has a large resistance to the fluid to be heated in the duct. c. Since the stage combustion is performed by the premixing method, even if the combustion amount is changed, there is always a flame near the stoichiometric air ratio, and the flame temperature is increased, so that the amount of NOx generated is large. d. The flame is large because of premixed combustion, and the surrounding fluid to be heated is involved in the flame, so that it is easily affected by the flame. For example, when the oxygen concentration of the fluid to be heated is low, unburned components are easily generated. An object of the present invention is to solve such a problem.

[0005]

In order to solve the above-mentioned problems, the present invention proposes a hot-air generating burner in which a knitted heat-resistant metal fiber-shaped concave combustion section is provided at the tip of a premixed gas supply pipe. Is what you do.

In the present invention, it is preferable that the concave-shaped combustion portion is formed by forming a desired concave shape with a mesh support such as expanded metal and joining the heat-resistant metal fiber to the mesh support by welding. suggest.

In the present invention, it is proposed that a dam plate be provided at the tip of the premixed gas supply pipe on the outer periphery of the combustion section.

In the present invention, it is proposed that a spark generating section be provided near the combustion section at the end of the premixed gas supply pipe.

According to the present invention, the premixed gas is burned in the combustion section made of the heat-resistant metal fiber, so that the flame retention is excellent. In particular, in the present invention, since the premixed combustion is performed on the surface of the heat-resistant metal fiber, the combustion is completed with a short flame, and since the combustion surface is inside the concave shape of the heat-resistant metal fiber, it is hardly affected by surrounding conditions. Therefore, in a state where the fluid to be heated is installed in the duct and used, it can be burned at a wide air ratio without being affected by the fluid to be heated, and does not blow out. Also, since a large wind box is not required and it is very compact, it does not take up space and has low resistance to the fluid to be heated in the duct.

[0010]

Next, an embodiment of the present invention will be described with reference to the drawings. FIGS. 1 to 4 show a first embodiment of a hot-air generating burner according to the present invention. The hot-air generating burner 1 includes a knitted heat-resistant metal fiber 3 at the tip of a premixed gas supply pipe 2. The combustion unit 4 has a concave shape. The heat-resistant metal fiber is formed by forming a heat-resistant metal into a fibrous shape, and a knit-shaped material can be formed by processing the heat-resistant metal fiber by knitting or weaving. Such a knitted heat-resistant metal fiber 3 is distributed, for example, as a metal fiber knit. In this embodiment, the concave shape of the combustion part 4 is a conical shape, but this shape can be various shapes as described later. As shown schematically in FIG. 4, the combustor 4 having the concave shape is formed into a predetermined concave shape, in this case, a conical concave shape by a mesh support 5 made of expanded metal or the like. And heat resistant metal fibers 3 are joined by welding. According to such a configuration method of the combustion unit 4, the combustion unit 4 in which the concave surface shape is not easily deformed can be easily configured. On the other hand, at the end of the premixed gas supply pipe 1, a weir plate 6 is provided around the combustion unit 4, and a spark generation unit 7 is further provided.

The hot-air generating burner 1 constructed as described above
Is installed in a duct 8 through which a fluid to be heated such as air flows as shown in FIG. In this state, the premixed gas is supplied to the combustion section 4 via the premixed gas supply pipe 1 and the spark is generated by the spark generation section 7 to ignite the premixed gas flowing out through the refractory metal fiber 3 and burn. Can be performed. Since this combustion is premixed combustion on the surface of the heat-resistant metal fiber 3, the combustion is completed with a short flame, and since the combustion surface is inside the concave shape of the heat-resistant metal fiber 3, it is not affected by the surrounding conditions. Excellent flame holding properties. In addition, since premixed lean combustion of high excess air can be performed, the flame temperature can be kept low, and the generation of NOx can be reduced. Further, the heat-resistant metal fibers 3 constituting the combustion section 4 having the concave shape are not overheated because they are always cooled by the premixed gas. And
Since the heat-resistant metal fiber 3 is rich in flexibility, even if it is heated, thermal expansion or contraction is naturally absorbed and no deformation occurs. In particular, in the hot-air generating burner 1 of this embodiment, the weir plate 6 is formed, and the recirculation flow is formed by the weir plate 6, so that the mixing of the fluid to be heated and the high-temperature combustion gas is promoted. Thus, efficient hot air generation is performed.

In the hot-air generating burner 1, the flame length and the amount of combustion can be changed by changing the apex angle α and height H of the conical shape shown in FIG. That is, when the height H is increased, the amount of combustion can be increased, and when the apex angle α is decreased, the flame becomes flat and the flame length can be shortened.

In the present invention, as described above, the concave shape of the combustion portion 4 is not limited to the conical concave shape described above,
As shown in FIGS. 5 to 9, various shapes can be employed. First, FIG. 5 schematically shows various concave shapes of the combustion part 4 when the premixed gas supply pipe 2 is cylindrical. FIG. 5A shows a cylindrical concave shape and the combustion part only on the peripheral wall. 4 and the end is closed. The one shown in (b) has a cylindrical concave shape, and the combustion part 4 is also provided on the end wall.
It is what constituted. Further, the one shown in (c) has a truncated conical concave shape, in which the combustion part 4 is formed only on the peripheral wall, and the end wall is closed. Further, the one shown in (d) is a truncated conical concave shape, in which the combustion part 4 is formed not only on the peripheral wall but also on the end wall. FIG. 5E shows an example in which the combustion section 4 is formed in a hemispherical concave shape.

FIGS. 6 to 9 show the premixed gas supply pipe 2 having the tip end side and the combustion section 4 in the shape of a horizontally long section, and increasing the combustion amount by adopting such a shape. be able to. 6, 7 and 8, the combustion portion 4 has a wedge-shaped horizontally long concave surface. In this case,
As in the case of the conical concave shape, the flame length, the amount of combustion, and the like can be changed by changing the apex angle α, the height H, and the lateral length L shown in FIGS. . That is, when the height H and the length L are increased, the amount of combustion can be increased, and when the apex angle α is decreased, the flame becomes flat,
Flame length can be shortened. FIGS. 9A and 9B show examples of various shapes of the horizontally long combustion section 4, and FIG. 9A shows an example in which the combustion section 4 is formed in a rectangular cylindrical concave shape over the entire surface, and FIG.
(A) has a rectangular cylindrical concave shape, but the combustion portion 4 is formed only on two opposing surfaces, and (c) shows a trapezoidal cylindrical concave shape and the combustion portion 4 is formed on the entire surface. d)
1 shows a trapezoidal cylindrical concave shape, in which the combustion portion 4 is formed only on two opposing surfaces, and (e) shows a shape in which the combustion portion 4 is formed in a semi-cylindrical concave shape.

[0015]

As described above, the present invention has the following effects. a. The combustion surface is the surface of the combustion section composed of heat-resistant metal fibers, and since premixed combustion is performed on this combustion surface, it has excellent flame holding properties, so it can be burned with a wide air ratio,
Does not blow out. b. The combustion surface is inside the concave shape of the heat-resistant metal fiber,
Further, since the combustion is premixed, the combustion is completed with a short flame, so that it is hardly affected by surrounding conditions. c. By performing premixed lean combustion of high excess air, the flame temperature can be kept low, and NOx can be reduced. d. Since the heat-resistant metal fibers constituting the combustion part are always cooled by the premixed gas, they are not overheated, and even if heated, the thermal expansion or contraction is naturally absorbed and no deformation occurs. e. Compared with the conventional burner, it has a very simple structure, the manufacturing cost is low, and the handling and maintenance are easy. f. Since the wind box portion is small, it is compact, the installation space in the duct is small, and the air resistance to the fluid is small. g. The length and shape of the combustion part can be freely designed,
The flame length and the amount of combustion can be changed. h. If a weir plate is formed, the recirculation flow is formed by this weir plate, so that mixing of the fluid to be heated and the high-temperature combustion gas is promoted, and efficient hot air generation is performed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a hot-air generating burner according to the present invention.

FIG. 2 is a longitudinal sectional view of FIG.

FIG. 3 is a sectional view showing a state where the burner of FIG. 1 is installed in a duct through which a fluid to be heated flows.

FIG. 4 is an explanatory diagram showing a configuration method of a combustion unit.

FIG. 5 is a perspective view showing another example of the shape of the combustion section.

FIG. 6 is a perspective view showing another embodiment of the hot-air generating burner according to the present invention.

FIG. 7 is a side view of the burner of FIG. 6;

8 is a schematic perspective view showing a state where the burner of FIG. 6 is installed in a duct through which a fluid to be heated flows.

FIG. 9 is a perspective view showing another example of the shape of the combustion section.

FIG. 10 is a perspective view of a conventional hot-air generating burner.

FIG. 11 is a sectional view of a main part of the burner of FIG. 10;

FIG. 12 is a schematic diagram showing a state where the burner of FIG. 10 is installed in a duct through which a fluid to be heated flows.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hot-air generating burner 2 Premixed gas supply pipe 3 Heat-resistant metal fiber 4 Burning part 5 Reticulated support 6 Weir plate 7 Spark generating part 8 Duct

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 3K017 AA01 AA02 AA03 AA06 AA07 AB06 AC01 AD08 AD10 AD12 AF02 AG06 3L113 AC04 AC54 AC74 AC76 DA07 DA14 DA17 DA22 DA26

Claims (5)

[Claims] 1. A hot-air generating burner characterized in that a concave-shaped combustion section made of a knitted heat-resistant metal fiber is formed at the end of a premixed gas supply pipe. 2. The hot-air generator according to claim 1, wherein the combustion portion has a desired concave shape formed by the mesh support, and is formed by joining heat-resistant metal fibers to the mesh support by welding. Burner 3. The hot-air generating burner according to claim 2, wherein the reticulated support is an expanded metal. 4. The hot-air generating burner according to claim 1, wherein a weir plate is provided at an end of the premixed gas supply pipe on an outer periphery of the combustion part. 5. The hot-air generating burner according to claim 1, wherein a spark generating section is provided near the combustion section at the end of the premixed gas supply pipe.