JPH08135932A - Powder flame-spraying burner - Google Patents

Abstract

PURPOSE: To ensure a powder flame-spraying burner using air as auxiliary combustion gas without causing flame lifting by inserting a powder supply pipe through the center of a main flame cylinder, surrounding a hole outer periphery of the main flame cylinder with an outer cover, and providing a flame keeping small hole in an outer cover bottom toward the outside. CONSTITUTION: A powder supply pipe 2 is inserted into a burner head 1 along a center line of the burner head with a pipe end slightly protruded from the burner head. A flange equipped main flame cylinder 3 is inserted into and fixed to a hole end of the burner head. A hole edge of the main flame cylinder 3 is located slightly withdrawn from the hole edge of the burner head. The hole end of the burner head surrounding the main flame cylinder 3 forms a cover pipe 11 of the main flame cylinder 3. A flame of the rear end of the main flame cylinder 3 forms a bottom surface of a space surrounded by the main flame cylinder and the cover pipe, and a plurality of flame keeping small holes 32 are provided in a line outwardly slantingly. The burner head 1 is welded to the tip end of a grip pipe 4, and mixture gas of fuel gas and air is supplied through the grip pipe 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder spraying burner used for melting powder of metal or ceramic and spraying it onto glass or bricks for mass coating, or for mass-producing small spheres of metal or ceramic. .

[0002]

2. Description of the Related Art In a conventional powder spraying burner, as shown in FIG. 3, a powder supply pipe B is inserted in the center of a burner A to supply oxygen and fuel gas to a fuel injection hole C and an end face of the burner A. Flames are separately ejected from the oxygen ejection holes D, and the powder is transported by the air flow in the supply pipe and supplied into the flame. For this reason, the total amount of gas supplied to the burner tends to be excessive, and since the powder cools the flame on top of it, the speed at which the flame surface travels backward is slow, and the flame easily causes a so-called lift that separates from the crater of the burner. Since many powders for thermal spraying have a high melting point in the past, oxygen was used as the auxiliary gas as described above, so the burning rate was high and there was no problem of flame lift.

However, some of the thermal spraying powders have a low melting point, so even if it is not necessary to use oxygen in view of the temperature of the flame, if air is used as the auxiliary combustion gas, the burner will enter the burner as described above. The total amount of gas supplied becomes excessive, and the flame lifts and sometimes blows off and disappears, resulting in a very poor thermal spraying result. For this reason, conventionally, oxygen is used even when spraying a powder having a low melting point, and it is very uneconomical because oxygen is expensive.

[0004]

To provide a burner for powder spraying which uses air as an auxiliary gas and does not cause lifting of a flame.

[0005]

[MEANS FOR SOLVING THE PROBLEMS] A powder supply pipe is inserted in the center of a burner head to which a mixed gas of fuel and air is supplied,
A sleeve is provided on the outer circumference of the mouth end of the main flame cylinder of the burner head, and several flame-holding small holes are provided obliquely outward at the bottom of the sleeve, and gas is ejected from the small holes to the inner surface of the sleeve. The flame holding was formed by spraying.

[0006]

Since the flame holding small hole is provided obliquely outward at the bottom of the sleeve surrounding the mouth end of the main flame of the burner head, it is formed in the space between the sleeve and the main flame of the burner head. The flame-holding formed hits the inner surface of the sleeve and forms flame-holding between the sleeve and the sleeve so as to swirl around the sleeve. For this reason, the flame holding effect is enhanced, and even if the total amount of the supply gas from the main flame cylinder and the powder supply pipe is excessive, the flame does not lift.

[0007]

FIG. 1 shows an embodiment of the present invention. In the figure, 1 is a burner head and 2 is a powder supply pipe. The powder supply pipe is connected to an air compressor (not shown), and powder is supplied into the pipe from a powder supply hopper. The powder supply pipe 2 is inserted into the burner head along the center line of the burner head 1, and its pipe end is slightly projected from the burner head. At the mouth end of the burner head, a main flame tube 3 with a collar as shown in detail in FIG. 2 is inserted and fixed. The rim of the main flame tube 3 is located at a position slightly retracted from the rim of the burner head. In this embodiment, the mouth end of the burner head surrounding the main flame cylinder 3 is the sleeve 11 of the main flame cylinder 3. The flange 31 at the rear end of the main flame cylinder 3 forms the bottom surface of the space surrounded by the main flame cylinder and the sleeve, and as shown in FIG. Are lined up. The burner head 1 is welded to the tip of the handle tube 4, and a mixed gas of fuel gas and air is supplied through the handle tube 4.

When the burner burns up to 30,000 kcal / h, the dimensions and angles of the parts shown in FIGS. The air amount of the mixed gas supplied to the burner is 0.8 to 1.1 times the theoretical value. Length of sleeve tube e 15 to 25 mm Length of main flame tube L 10 to 20 mm Powder supply tube inner diameter d 10 to 19 mm Sleeve inner diameter D 30 to 40 mm Main flame tube inner diameter D'16 to 25 mm Main flame tube wall thickness t 2 to 5 mm Flame holding small hole diameter m 1 to 3 mm Angle of the small hole α 30 to 60 ° The above-mentioned dimensions may be determined in proportion to the square root of the combustion amount. Each of the above-mentioned values has a range, but it may be selected within the above range so that the flame shape becomes appropriate according to the kind of powder. With the above-mentioned configuration, a swirl flame holding that naturally surrounds the main flame cylinder in either direction is formed in the sleeve, but the direction of the flame holding small hole is inclined slightly outward and tilted in the circumferential direction. A swirling flow may be forcibly created.

[0009]

As described above, the burner for powder spraying according to the present invention encloses the main flame cylinder with the sleeve, and forms the flame holding so as to contact the inner surface of the sleeve in the space between the main flame sleeve and the sleeve. The flame holding is formed so as to swirl between the sleeve and the main flame cylinder, and since the flame holding swirls at the root of the main flame, the flame holding function is enhanced and is supplied to the burner. Even if the total amount of gas is increased, the lift of the main flame does not occur. Therefore, even if air is used as the auxiliary gas, stable powder spraying can be performed. Currently, oxygen costs about 50-60 yen / m ³ for small and medium-sized consumption,
When using methane gas with a burner of 30,000 kcal / h, the amount of oxygen is about 6 m ³ per hour, so ³ hours per hour
Although it costs as much as 00 yen, according to the present invention, this amount becomes unnecessary and the economical efficiency of powder spraying with a low melting point can be improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view of an embodiment of the present invention.

FIG. 2 is a detailed view of the above-mentioned main part.

FIG. 3 is a perspective view of a conventional example.

[Explanation of symbols]

 1 Burner Head 2 Powder Supply Pipe 3 Main Flame Cylinder 11 Sleeve 31 Collar 32 Flame Retaining Small Hole

Claims (1)

[Claims] 1. In a burner to which a mixed gas of fuel gas and air is supplied, a powder supply pipe is inserted through the center of the main flame cylinder, the outer periphery of the main flame cylinder is surrounded by an outer jacket, and the bottom of the outer jacket is slanted. A burner for powder spraying, characterized in that a flame holding small hole is provided toward the outside.