JPS6145495B2 - - 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 O ₃ H ₆ 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.
_O2H2 was _used . However, since O ₂ H ₂ has the property of causing self-decomposition, 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 O ₂ H ₈ ,
The object of the present invention is to provide a burner nozzle for powder thermal spraying that can obtain a sufficiently high flame temperature even when using O ₄ H ₁₀ or the like and can flame spray powder materials with a high melting point such as ceramics. Furthermore, another object of the present invention is to provide a burner nozzle capable of flame spraying powder raw materials at a high welding rate. An embodiment of the present invention will be described below.
1, 2 and 3 show a burner nozzle body 9 according to this embodiment. Figures 1 and 2
In the figures and FIG. 3, 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 cone-shaped cavity 13 and a gas-solid flow supply hole 14 formed of a cylindrical cavity having a smaller diameter than the cavity 12 are formed. These cavities 12,
Reference numeral 13 constitutes 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. Premixing/combustion chamber 1
The end of 5 on the other cavity 13 side is connected to the gas-solid flow supply hole 14 described above. In this way, a gas-solid flow (a flow in which powder raw material, e.g. A ₂ O ₃ is transported with a fuel gas such as C ₃ H ₈ , C ₄ , H ₁₀ etc., e.g. O ₃ H ₈ ; hereinafter,
(similar) is introduced into the premixing/combustion chamber 15 through the gas-solid flow supply hole 14, and is then turned into a flame and injected from the flame jet port 15a. In addition, the outer diameter of the inner cylinder 10 on the premixing/combustion chamber 15 side 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 cylinder 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. Wall surface (conical surface) of cavity 13 of premixing/combustion chamber 15
are provided with four small diameter first combustion-supporting gas supply holes 17a (four in this embodiment, generally not limited to four but plural) at two different positions in the generatrix direction.
..., 17b, ... are provided in a circular arrangement. These supply holes 17a, 17b, . . . are bored in the tangential direction of the wall surface (conical surface) of the cavity of the premixing/combustion chamber 15 from the combustion-supporting gas guide hole 16 to the premixing/combustion chamber 15. It is being Further, on the wall surface (conical surface) of the cavity 13 of the premixing/combustion chamber 15, eight second combustion-supporting gas supply holes 17c, . are arranged in a circular arrangement. The second combustion-supporting gas supply holes 17c, . It is perforated up to the mixing/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, ...17.
It is supplied to the premixing/combustion chamber 15 via c, . . . and 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, 2, and 3, powder raw material A ₂ O ₃ is transported to fuel gas C ₃ H ₈ as a gas-solid stream of about 20
The gas-solid flow is guided through the gas-solid flow supply hole 14 as shown by the arrow a at a flow rate of m/sec, and further flows into the premixing/combustion chamber 15.
It is squirted. In addition, the combustion-supporting gas is connected to the combustion-supporting gas guide hole 1.
6 at a flow rate of about 20/sec as shown by the arrow b, and then the combustion-supporting gas supply holes 17a,...,
17b, ... 17c, ... at a flow rate of approximately 150 m/sec as shown by arrows c, d, and e, respectively.
It is ejected into the combustion chamber 15. As a result, the fuel gas and combustion supporting gas are mixed. That is, the combustion supporting gas supply holes 17a,...,17
Since b,..., 17c,... are provided at different positions in the generatrix direction, the gas-solid flow described above first passes near the supply holes 17a,..., and then sequentially passes through the supply holes 17b,..., 17c,... passing near each of them. As a result, the combustion-supporting gases ejected from the supply holes 17a, . .
At this time, the first combustion supporting gas supply holes 17a,...17b,
... is oriented in the tangential direction of the conical surface of the cavity 13 of the premixing/combustion chamber 15, and the second combustion supporting gas supply hole 1
7c, ... are in the direction of the flame outlet 15a and are premixed and
Since the gas is converged on the axis of the combustion chamber 15, the above-mentioned jetting of the combustion-supporting gas does not cause disturbances in the flow that prevent the smooth supply of the gas-solid flow from the gas-solid flow supply hole 14. do not have. 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 over the area outside the flame jet port 15a from the premixing/combustion chamber 15, and even if the powder raw material in the gas-solid flow has a high melting point, the flame It is completely melted up to the area outside the spout 15a. Flame spout 15a
The flow velocity of the gas (flame) ejected from is approximately 250
m/sec, and the flow rate (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 first combustion-supporting gas supply holes 17a, . . . are arranged in an annular arrangement on the conical surface of the premixing/combustion chamber 15, and are oriented in the tangential direction of this conical surface. Similarly, the first combustion supporting gas supply holes 17b, . . . are also provided in the premix combustion chamber 15. Further, the second combustion-supporting gas supply holes 17c, ... are arranged in an annular manner on the conical surface of the premixing/combustion chamber 15, and converge in the direction of the flame jet port 15a and on the axis of the premixing/combustion chamber 15. It is set in. Therefore, the powder raw material in the gas-solid flow is not needlessly scattered, and the powder raw material in the gas-solid flow is concentrated at the center of the flame (in the direction of the central axis of the premixing/combustion chamber 15). Therefore, thermal spraying with a high welding rate can be achieved. According to thermal spraying experiments using the above nozzle, as shown in the table, O ₃ H ₈ and A ₂ O ₃ (pure) were used as fuel gas and powder raw material, respectively.
Even when using this method, thermal spraying was possible with an extremely high welding rate.

[Table] In this example, the powder raw material was transported using fuel gas as a gas-solid flow, but the powder raw material may be transported using a mixed gas of fuel gas and combustion supporting gas. Furthermore, although the second combustion-supporting gas supply holes 17c are small diameter holes arranged in an annular arrangement, they may be formed by annular slits. Furthermore, the second combustion-supporting gas supply holes may be provided in multiple stages in the longitudinal direction of the premixing/combustion chamber. As described above with respect to the embodiments, according to the present invention, it is possible to completely mix the combustion-supporting gas into the gas-solid flow, and as a result, it is possible to achieve a high flame temperature, and moreover, the powder raw material in the gas-solid flow can be mixed with the flame. Since it can be collected at the center of the fuel gas, powder raw materials with high melting points can be thermally sprayed with a high welding rate even if C ₃ H ₈ , C ₄ H ₁₀ , etc. are used as the fuel gas.

[Brief explanation of the drawing]

The drawings show one embodiment of the invention.
2 is a cross-sectional view taken along the - line in FIG. 1, and FIG. 3 is a cross-sectional view taken along the - line in FIG. 1. DESCRIPTION OF SYMBOLS 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,...
First combustion-supporting gas supply hole, 17c...second combustion-supporting gas supply hole.

Claims (1)

[Claims] 1. A premixing/combustion chamber having a front end opening as a flame outlet, a circular cross section and a cavity that expands toward the flame outlet, and a rear end of the cavity having a gas-solid flow supply holes for ejecting a gas-solid flow towards the premixing/combustion chamber, arranged in a ring shape around the axis of the cavity, and oriented in the tangential direction of the circular cross section; A plurality of communicating first combustion-supporting gas supply holes are formed in one stage or in a plurality of stages in the front-rear direction of the cavity, are arranged in an annular shape around the axis of the cavity, and gradually approach the axis toward the flame jet port. A powder characterized by forming one stage or a plurality of stages of second combustion-supporting gas supply holes in the front-rear direction of the cavity, which are formed by drilling or slits or groups of small holes drilled or arranged in such a direction. Burner nozzle for thermal spraying.