JPH025209Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[Industrial Application Field] The present invention relates to a gas burner used in various industrial furnaces and thermal equipment. [Prior art] In various kilns, especially heat retention furnaces and heat treatment furnaces,
When heating or retaining heat of a long object to be heated, a heating method is adopted in which a large number of gas burners are arranged along the long axis of the object to achieve uniform heating. In this way, when installing a large number of gas burners, for example 30 to 100, it is especially important to have a simple structure, low price, and easy maintenance, and to be able to spread over a wide range with fewer phenomena such as blowing out. Therefore, it is desired that the amount of heat output can be increased or decreased. The gas burner shown in Fig. 6 is the gas burner shown in Fig. 6.1a in Section 187 of "Combustion Equipment Engineering" published by Nikkan Kogyo Shimbun on January 20, 1980, with the fuel in the center of the shaft. The fuel gas 1a is ejected from the inner supply pipe, and at the same time combustion air is ejected from the outer air supply pipe 2 while being swirled by the swirling blades 3, and the fuel gas and air are mixed in the burner tile 4 and combustion is performed. It is simple and combustion control is easy, and it is widely used in various industries. [Problem to be solved by the invention] In ordinary heat retention furnaces or heating furnaces, it is desirable to have a wide temperature control range from low temperature range to high temperature range, and in addition, there are cases where it is necessary to equalize the temperature inside the furnace. be. When performing uniform heating, it is effective to increase the ratio A/A ₀ between the amount of air actually used and the theoretical amount A ₀ , that is, the excess air coefficient (hereinafter referred to as m value) to about 2.0 to 3.0. However, ordinary gas burners, including the example shown in FIG. 6, have many problems in terms of reliability due to blowout. Furthermore, the m value is set to about 1.0 in the high temperature range,
Even if efficient heating is achieved by setting the flow velocity of the fuel gas or combustion air to, for example, 15 m/s, the phenomenon of blow-off tends to occur, and stable combustion cannot be expected. Such problems are particularly noticeable in conventional gas burners made of metal tubes. In other words, there are no highly reliable gas burners with limited equipment costs and simple structures, and there are also burners that can use a variety of gases such as LNG, COG, or propane gas, and are suitable for uniform heating in low-temperature ranges. The current situation is that there is nothing. For example, there are approximately 80 problems to be solved with this invention.
To provide a highly economical gas burner that hardly causes a blow-out phenomenon even when the temperature control range is wide when performing uniform heating in a long heat retention furnace in which gas burners are arranged on both sides. [Means for Solving the Problems] The inventors of the present invention have developed a gas burner that is suitable for a wide temperature control range, has a simple structure, and is highly reliable. a fuel gas supply metal inner pipe having a swirler vane, the inner pipe having a diameter substantially the same as the expanding diameter of the swirler vane, and having the inner pipe built therein so that the tip of the swirler vane and the end of the ejection port substantially coincide with each other; an air supply metal outer tube having a lid for holding the inner tube at the center of its axis at an end; a flame retaining rod fixed across the end of the nozzle in a diametrical direction; and a gas mixing lumen; We devised a gas burner consisting of a gas-mixing metal cylinder fitted onto the outside of the cylinder. [Example] Hereinafter, the specific configuration, operation, and effects of the present invention will be explained as follows.
Description will be made based on the embodiments shown in FIGS. 5 to 5. FIG. 1 is a partially cutaway front view of the gas burner according to the present invention, in which the outer circumferential surface 8b of the spout end 8 of the fuel gas supply metal inner pipe 7 connected to the fuel gas main pipe 5 via the joint 6 has no. As shown in the detailed views of FIGS. 4 and 5, petal-shaped swirling vanes 9a to 9d (9c is not shown for convenience of explanation) are welded to the fuel gas supply metal inner pipe 7 with a lid. The air supply metal outer tube 11 held at the center of the shaft by the body 10 has approximately the same diameter as the expanding diameter of the swirl vanes 9a to 9d, and its ejection port end 12 is located at the tip of the swirl vanes 9a to 9d (9d ₁
(represented by ). Further, as shown in FIG. 1, in this example, the lid 10 is constructed as a flange welded to the fuel gas supply metal inner pipe 7, and the outer periphery is welded to the inner surface of the air supply metal outer pipe 11. has been done. 1
3 indicates a metal packing material for preventing gas leakage. Next, the gas mixing metal tube 14 has a gas mixing lumen 15 and a flame retaining rod 16 fixed across the diametrical direction, and the tip end 11 of the air supply metal outer tube 11
It is externally fitted and fixed to a. Furthermore, an air supply branch pipe 17 is connected to the rear end 11b of the air supply metal outer pipe 11, and the air supply branch pipe 17 also communicates with an air main pipe (not shown) via a flange 18. Since the gas burner 19 of the present invention has the above-mentioned configuration, the gas ejected from the ejection port 8a of the fuel gas supply metal inner pipe 7 flows through the swirl vanes 9a to 9.
Since the air from the air supply metal outer tube 11 given a swirling motion by d is vigorously stirred in the gas mixing lumen 15, the combustion efficiency is extremely high. Next, FIG. 2 is a schematic plan view of the gas mixing metal tube 14, in which a flame holding rod 16 fixed in the diametrical direction at the spout end 14a of the gas mixing metal tube 14 has a gas stirring function and also has a gas mixing function. Since it maintains a high temperature due to the heat generated after the initial combustion in the cavity 15, it has an excellent flame retention effect. In addition, the tips of the swirl vanes 9a to 9d and the spout end 12 of the air supply metal outer tube 11 in the present invention are as follows:
As described above, since they are configured to substantially coincide on the same plane, the combustibility is good and the phenomenon of blow-out is extremely small. Although a theoretical analysis of this has not been performed at present, it has been confirmed in numerous experiments that the combination with the gas mixing metal cylinder 14 has a remarkable effect in supplying combustion air at low pressure and large flow rate. . It is well known that combustion efficiency can be increased by mixing and stirring fuel gas and air. Section describes the theory and design method for premix combustion type nozzles and diffusion combustion type nozzles. However, there is no suggestion regarding a gas burner having a simple triple structure of metal tubes and having both premixing and diffusion combustion functions as in the present invention. Next, details regarding the configuration of the swirl vanes 9a to 9d and the gas mixing lumen 15 according to the present invention will be explained. FIG. 3 is a schematic front view of the gas burner according to the present invention, and for the sake of explanation, the flame retaining rod 16 is not shown. FIG. 4 is a schematic longitudinal section of the gas burner tip section taken along the line AA in FIG. 3, and the flame retaining rod 16 is shown by a broken line. The swirling vanes 9a to 9c are each made of a rectangular metal piece, and are arranged at an angle of 45° with respect to the longitudinal direction of the fuel gas supply metal inner pipe 7 at the ejection port end 8 of the fuel gas supply metal inner pipe 7. Base 90 at inclination angle
(represented by swirling vanes 9d) are welded to the outer surface of the fuel gas supply metal inner pipe 7. Therefore, the fuel gas supply metal inner tube 7 to which the swirl vanes 9a to 9d are welded has an appearance as if it had outward-opening petals. Therefore, in the present invention, the fuel gas supply metal inner pipe 7 is defined as having swirling vanes welded in a petal shape, but the number of swirling vanes is about 2 to 6 to be sufficiently effective, and the above-mentioned inclination angle is 30°. A good effect was obtained at ~50°. Accordingly, in the present invention, a stepped portion 20 corresponding to the thickness of the air supply metal outer tube 11 is formed on the ejection end 12 of the air supply metal outer tube 11 and the inner surface of the gas mixing metal tube 14. It has been found that the presence of this minute step 20 generates eddy currents during gas mixing and reduces the phenomenon of blow-off. That is, we have experienced that in a gas burner in which the gas mixing metal tube 14 is removed and the air supply metal outer tube 11 is extended to form the same space as the gas mixing lumen 15, there are many blow-out phenomena, which poses a practical problem. In this invention, the triple structure of metal tubes has a unique function due to its combination, and together with the functions of the gas mixing lumen 15 and the flame holding rod 16, it prevents backfire that tends to occur in premixed combustion. There is no fear, and there is no need to worry about blow-off, which tends to occur with diffuse combustion. That is, the gas burner of the present invention has a two-stage flame retention function and can always maintain a stable combustion condition. Regarding the gas burner of the present invention shown in Fig. 1
Table 1 shows the LNG combustion test results. Table 2 shows the meanings of the symbols in Table 1. As is clear from Table 1, the gas burner of the present invention exhibits very good combustion over a wide range of the m value of 0.60 to 2.78, and the air flow rate also ranges from 50Nm ³ /Hr to 130Nm ³ /Hr in this example. It was able to handle a wide range of HR. The approximate dimensions of the gas burner are a fuel gas supply metal inner tube outer diameter of 34 mm, an air supply metal outer tube outer diameter of 76.3 mm, a gas mixing metal tube outer diameter of 89.1 mm, and a fixed length of the gas mixture metal tube and air supply metal outer tube. The length is 450mm, and the material is stainless steel.

【table】

【table】

[Effect of idea]

The gas burner according to the present invention has a simple structure, no failures, easy maintenance and inspection, and has little blowout, so it can be used in a wide range of m values, and therefore can be used in a wide temperature control range in thermal equipment. is possible.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway front view of a gas burner according to the present invention, Fig. 2 is a schematic front view of a gas mixing metal tube, Fig. 3 is a schematic front view of a gas burner according to the present invention, and Fig. 4 is a front view of the gas burner tip. FIG. 5 is a partially cutaway schematic perspective view of the gas burner according to the present invention. FIG. 6 shows a schematic cross-sectional view of a conventional gas burner. 1: fuel supply inner pipe, 1a: fuel gas, 2: air supply outer pipe, 3: swirl vane, 4: burner tile,
5: Fuel gas main pipe, 6: Joint, 7: Fuel gas supply metal inner pipe, 8: Spout end, 8a: Spout port, 9a
~9d: swirling vane, 10: lid, 11: air supply metal outer tube, 11a: tip, 11b: rear end, 1
2: Spout end, 13: Metal packing material, 14: Gas mixing metal tube, 14a: Spout end, 15: Gas mixing lumen, 16: Flame holding rod, 17: Air supply branch pipe, 1
8: flange, 19: gas burner, 20: paragraph,
90: Base.

Claims (1)

[Scope of utility model registration request] a fuel gas supply metal inner pipe 7 having a plurality of swirl vanes welded to the spout end 8 in the shape of outwardly opening petals;
It has approximately the same diameter as the expanded diameter of the swirling vane, has the inner tube 7 built-in so that the tip of the swirling vane and the spout end 12 substantially coincide with each other, and holds the inner tube 7 at the center of the axis at the other end. It has an air supply metal outer tube 11 equipped with a lid body 10, a flame retaining rod 16 fixed across the diametrical direction of the spout end 14a, and a gas mixing lumen 15, which is externally fitted and fixed to the outer tube 11. A gas burner consisting of a gas mixing metal cylinder 14.