JPS6145497B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a burner nozzle for powder thermal spraying used in flame thermal spraying. In conventional powder spray equipment, it is used as fuel gas.
When using gases such as C ₃ H ₈ and C ₄ H ₁₀ , a sufficiently high flame temperature cannot be obtained, and ceramics such as A
It was not possible to flame spray a powder material with a high melting point such as ₂ O ₃ . Therefore, when flame spraying a powder raw material with a high melting point, it is generally used as a fuel gas.
C ₂ H ₂ was used. However, C ₂ H ₂ has the property of causing self-decomposition and it is necessary to keep the supply pressure low, making it unsuitable for large-capacity processing. This invention was made in consideration of these circumstances, and its purpose is to use C ₃ H ₈ ,
It is an object of the present invention to provide a burner nozzle for powder thermal spraying that can obtain a sufficiently high flame temperature even when using C ₄ H ₁₀ or the like and can flame spray powder materials with a high melting point such as ceramics. Another object of the present invention is to provide a burner nozzle that can flame spray powder raw materials with a high welding rate. An embodiment of the present invention will be described below.
Figures 1 and 2 illustrate this embodiment.
1 and 2, a cylindrical outer cylinder 11 is fixedly attached to an inner cylinder 10 made of copper so as to surround it. The inner cylinder 10 has a cylindrical cavity 12, a truncated conical cavity 13, and this cavity 12.
A gas-solid flow supply hole 14 consisting of a cylindrical cavity having a smaller diameter than that of the gas-solid flow supply hole 14 is formed. These cavities 1
Reference numerals 2 and 13 constitute a premixing/combustion chamber 15, and the end of the premixing/combustion chamber 15 on the cavity 12 side is opened as a flame jet port 15a. The end of the premixing/combustion chamber 15 on the other cavity 13 side is connected to the gas-solid flow supply hole 14 described above. Thus, gas-solid flow (flow when powder raw material, for example A ₂ O ₃ is transported with fuel gas such as _{C 3 H 8} , O _{4 H 10} , etc.).
The same applies hereinafter) is introduced into the premixing/combustion chamber 15 via the gas-solid flow supply hole 14, and is then turned into a flame and injected from the flame jet port 15a. Further, the outer diameter of the cylinder 10 on the side of the premixing/combustion chamber 15 matches the inner diameter of the outer cylinder 11, and this premixing/combustion chamber 15 side matches the inner diameter of the outer cylinder 11.
On the combustion chamber 15 side, the outer peripheral surface of the inner cylinder 10 and the inner peripheral surface of the outer periphery 11 are in close contact with each other. On the other hand, the inner cylinder 10
The outer diameter of the gas-solid flow supply hole 14 side is smaller than the inner diameter of the outer cylinder 11, and on the gas-solid flow supply hole 14 side, there is a gap between the outer peripheral surface of the inner cylinder 10 and the inner peripheral surface of the outer cylinder 11. An annular gap is formed in the opening, and this gap constitutes the combustion-supporting gas guide hole 16. On the wall surface (pyramidal surface) of the truncated cone forming the cavity 13 of the premixing/combustion chamber 15, there are four ( Generally, there are a plurality of small-diameter combustion-supporting gas supply holes 17 (in this example, four holes each).
a, . . . , 17b, . . . , 17c, . . . are opened in a circular arrangement. These supply holes 17
a, . . . , 17b, . It is perforated up to the premixing/combustion chamber 15 side. In this way, oxygen gas or oxygen-enriched air (hereinafter referred to as combustion-supporting gas) is supplied to the combustion-supporting gas guide hole 16 and the combustion-supporting gas supply hole 17a,...17b,...17c,
... is supplied to the premixing/combustion chamber 15, where it is mixed with the aforementioned gas-solid stream. Next, the function of the burner nozzle for powder thermal spraying configured as described above will be explained. In Figures 1 and 2, powder raw material A ₂ O ₃ is fuel gas.
C ₃ H ₈ is transported as a gas-solid stream, introduced into the gas-solid stream supply hole 14 as shown by arrow a at a flow rate of about 20 m/sec, and further ejected into the premixing/combustion chamber 15. In addition, the combustion-supporting gas flows through the combustion-supporting gas guide hole 16 for approximately 20 minutes.
introduced as shown by arrow b at a flow rate of m/sec,
After that, combustion supporting gas supply holes 17a,..., 17b,
..., 17c, ... and is injected into the premixing/combustion chamber 15 as shown by arrow c at a flow rate of about 150 m/sec. As a result, the fuel gas and the combustion supporting gas are completely mixed. That is, the combustion supporting gas supply holes 17a,...17b,
...17c, ... are provided at different positions in the generatrix direction, so the gas-solid flow described above first passes near the supply holes 17a, ..., and then sequentially passes through each of the supply holes 17b, ..., 17c, ... passing near. As a result, this gas-solid flow is first mixed with the combustion supporting gas ejected from the supply holes 17a,...
Thereafter, the combustion supporting gases ejected from the supply holes 17b, . . . , 17c, . . . are sequentially mixed. At this time, each combustion supporting gas supply hole 17a,..., 17b,
..., 17c is on the axis and the flame outlet 15a
Since the holes are formed so as to converge in the direction of , the smooth supply of the gas-solid flow from the gas-solid flow supply hole 14 is hindered and the flow is disturbed by the above-mentioned jetting of the combustion-supporting gas. There is no. In this way, the gas-solid flow is smoothly supplied, and moreover, the combustion supporting gas is completely mixed with the gas-solid flow. Therefore, a high flame temperature zone is formed extending from the premixing/combustion chamber 15 to the area outside the flame jet port 15a, and even if the powder raw material in the gas-solid flow has a high melting point, the flame jet does not occur. It is completely melted up to the area outside the outlet 15a. The flow velocity of the gas (flame) ejected from the flame outlet 15a is approximately 250 m/
sec, and the flow velocity (velocity) of the mostly molten powder raw material is approximately 150 m/sec. The powder raw material is ejected from the flame outlet 15a at this flow rate, completely melted in the flame, and then welded to the base material (not shown). Further, the combustion-supporting gas supply holes 17a, ... are arranged in an annular arrangement on the conical surface of the premixing/combustion chamber 15, and are arranged on the axis so as to converge toward the flame jet port 15a. Also, combustion supporting gas supply hole 1
7a, . . . , 17b, . The powder raw material can be concentrated at the center of the flame (in the direction of the central axis of the premixing/combustion chamber 15), and therefore thermal spraying with a high deposition rate can be achieved. According to thermal spraying experiments using the above nozzle,
As shown in the table, even when C ₃ H ₈ and A ₂ O ₃ (pure) were used as the fuel gas and powder raw material, thermal spraying could be performed with an extremely high deposition rate.

[Table] In this example, a powder raw material transported by fuel gas was used as a gas-solid flow, but a mixed gas powder raw material of fuel gas and combustion supporting gas may be transported. Further, although the combustion-supporting gas supply holes are arranged in an annular arrangement and have small diameters, they may be formed by annular slits. As described above with respect to the embodiments, according to the present invention, the combustion supporting gas can be completely mixed into the gas-solid flow,
As a result, a high flame temperature can be achieved, and the powder raw material in the gas-solid flow can be collected at the center of the flame, so even if C ₃ H ₈ , C ₄ H ₀₀ , etc. are used as fuel gas, high melting point powder can be obtained. Body materials can be thermally sprayed with a high welding rate.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the present invention, in which FIG. 1 is a cross-sectional view taken along the - line in FIG. 2, and FIG. 2 is a vertical cross-sectional view. 10... Inner cylinder, 11... Outer cylinder, 14... Gas-solid flow supply hole, 15... Premixing/combustion chamber, 15a... Flame jet port, 16... Combustion supporting gas guide hole, 17a, 17b, 1
7c... Combustion supporting gas supply hole.

Claims (1)

[Claims] 1 It has a premixing/combustion chamber consisting of a cavity whose front end opens as a flame outlet and whose cross section widens in the direction of the flame outlet, and the rear end of the cavity has air flowing into the cavity. A gas-solid flow supply hole for ejecting a solid flow is arranged in a row, and further arranged in an annular shape around the axis of the cavity, and has a direction gradually approaching the axis toward the flame spout. A burner nozzle for powder thermal spraying, characterized in that a combustion-supporting gas supply hole is formed by forming a plurality of arranged small hole groups or slits in the front-rear direction of the wall of the cavity.