JP2500032Y2 - Centrifugal sprayer - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centrifugal atomization method device for producing powder by finely crushing a molten metal or alloy.

[0002]

2. Description of the Related Art As a method for obtaining powder by spraying molten metal,
The centrifugal atomization method has been conventionally known. This method is characterized in that the molten metal is introduced to the surface of a disk-shaped high-speed rotating body, the kinetic energy of the rotating body is applied to the molten metal, and the molten metal is scattered by a centrifugal force and pulverized.

This method has the features that the equipment is relatively small, that the atmosphere in the spray chamber is easy to adjust, and that it is also suitable for the production of powders of various kinds of metals and alloys in small quantities. There is. Further, another feature is that the particle size of the obtained powder can be freely adjusted by changing the speed of the rotating body.

[0004]

The conventional centrifugal spraying device has the following problems. In general, a rotating body having a convex shape, a flat shape, a concave shape or a cup shape as shown in FIG. 2 is used. In general, gravity is used to supply the molten metal, so that the rotation axis is vertical and the rotating body is rotated in a horizontal plane. In this case, it is ideal that all the molten metal supplied to the central portion reaches the peripheral portion uniformly as shown in FIG. However, as shown in FIG. 4, a considerable portion of the molten metal jumps out without reaching the peripheral portion, and since such molten metal is not provided with sufficient kinetic energy, the powder particle size becomes coarse,
In addition, some of it hits the walls of the spray chamber and produces flakes, which significantly deteriorates the product yield of the powder. In particular, when the number of rotations is increased, such a tendency is intensified, and it is difficult to obtain a fine powder having a sharp particle size distribution. An object of the present invention is to solve these problems, improve productivity and workability, and stably produce a powder having a fine particle size and a sharp particle size distribution on an industrial scale.

[0005]

According to the present invention, there is provided a cap which covers an open surface of a rotating body, is separated from the rotating body at a central portion of the rotating body, and is in contact with the rotating body at a peripheral portion, and further is provided at a central portion of the rotating body. A cylindrical small chamber is provided, a small hole is provided around the cylindrical small chamber, molten metal is injected into the small chamber from the outside, and the molten metal is guided between the rotating body and the cap through the small hole. By spraying through the gap between the rotor and the cap, the molten metal is prevented from spattering from the middle of the rotor, and the molten metal is given a uniform and sufficient kinetic energy, resulting in a fine and sharp grain size. The gist is that the powder having a distribution can be stably manufactured on an industrial scale. The present invention will be described with reference to the drawings.

First, the device of the present invention will be described. FIG. 1 shows an example of a rotating body of a spraying device according to the present invention. As shown in FIG. 1 (a), an example of a rotating body in the spraying device of the present invention is connected to the main body 1 as a structure of the rotating body, and is provided with a side wall 2 and a cone-shaped wall surface 3 on the outer peripheral portion, and further rotates It is characterized in that a small chamber 4 and a cap 5 for preventing molten metal from jumping out are provided in the center of the body. The rotating body 1 needs an appropriate depth to hold the molten metal. Therefore, the rotating body 1
The cap 5 and the cap 5 are separated from each other in the central portion of the rotating body 1, but are in contact with each other in the peripheral portion of the rotating body to prevent the molten metal from splashing. The cap 5 is pushed open by the centrifugal force of the molten metal, and sprayed to the outside through a slight gap generated between the rotor 1 and the cap 5. As described above, the cap 5 is normally in contact with the rotating body 1, but it is necessary to configure the cap 5 so as to have elasticity so as to slightly separate from the rotating body 1 during spraying. The molten metal is supplied to the small chamber inlet 6 at the center of the rotating body, is discharged from the small chamber outlet 7 and reaches the side wall 2 along the rotating body. The centrifugal force of the molten metal pushes the pop-out prevention cap 5 to open it, and further The kinetic energy of the rotating body is sufficiently imparted from the outer peripheral portion of the cone wall surface 3 to the atomized wall surface 3 for spraying. The small chamber 4 needs a small chamber inlet 6 which is an inlet of the molten metal and a small chamber outlet 7 which is a small hole which is an outlet. The small chamber inlet 6 needs to have an appropriate size for introducing the molten metal, and if it is too small, it is difficult to align the center of the molten metal supply nozzle and workability is deteriorated. On the other hand, if it is too large, it is inevitable that the outer diameter of the small chamber must be increased, which increases the rotational moment and is apt to cause shake due to eccentricity or the like, which is not appropriate. Therefore, usually 4 to 25
mmφ is suitable, and more preferably 5 to 15 mmφ. Further, the small chamber outlet 7 needs to be arranged between the upper surface of the main body 1 of the rotating body and a cap described later, and more preferably, the lower end of the outlet is arranged so as to contact the upper surface of the main body 1 of the rotating body. If the diameter of the small holes is too small, there is a problem that it is difficult to make holes when manufacturing the small chamber, and the molten metal is easily clogged. On the other hand, if it is too large, the molten metal introduced into the small chamber will easily flow out from the uneven small holes, and it will be difficult for the molten metal to flow uniformly over the entire circumference of the rotating body. Therefore, a hole diameter of 0.5 to 3 mmφ is desirable. In addition, it is necessary to distribute the molten metal evenly over the entire circumference of the rotating body. For that purpose, it is desirable that the number of holes is as large as possible due to the structure.
It is desirable to arrange 20 pieces at equal intervals. Inner diameter d of small chamber 4
Is 1mm from the diameter of the small chamber inlet 6 as shown in Fig. 1 (a).
It is necessary to increase the above to surely prevent the backflow of the molten metal. Therefore, 4 to 30 mmφ is suitable. The height h of the small chamber 4 is preferably 5 to 30 mm. The molten metal jump-out prevention cap 5 is made of an elastic and heat-resistant metal thin plate, and if the thickness thereof is too thin, it becomes difficult to process, and it is easily deformed by the heat when the molten metal is sprayed, and does not serve as a cap. On the other hand, if it is too thick, it cannot be pushed open due to the centrifugal force of the melt,
The molten metal accumulates in the rotating body, and the heat capacity becomes large, so that solidification is likely to occur, which causes damage to the rotating body. For example, if the material is SUS304, the thickness of the cap 5 is 0.1-1.0 m.
m, preferably 0.2 to 0.6 mm is suitable.

The rotating body in the spraying device of the present invention has only a shape having a side wall 2 perpendicular to the main body of the rotating body as shown in FIG. However, the present invention can also be applied to a cup-shaped product such as (b) and a cone-shaped product such as (c). In particular, when the rotating body of the present invention is used, it is possible to rotate the rotating shaft 8 horizontally, and by doing so, the internal volume of the spray chamber 11 can be reduced,
Equipment cost will be reduced, and melting work and spraying work will be monitored.
It is possible to take out the powder and the like on almost the same floor and to bring about an effect such that the workability is remarkably improved.

[0008]

The present invention rotates the molten metal supplied to the small chamber at the center of the rotating body by covering the opening of the rotating body to which the molten metal is introduced with the cap and providing the cylindrical small chamber at the center of the rotating body. It is surely supplied between the body and the cap, spread evenly around the periphery of the rotating body, and surely prevents the molten metal from jumping out from the middle of the rotating body, so that sufficient kinetic energy of the rotating body is imparted to the molten metal. Moreover, the molten metal is discharged from the narrow gap between the rotor body 1 and the cap 5. Therefore, it is possible to obtain a finer powder having a sharp particle size distribution.

[0009]

[Example] Sn63wt% -Pb alloy which is eutectic solder
It melts at 320-330 ° C., and by using the centrifugal spraying device shown in FIG. 5, the rotor of the present invention shown in FIGS. 1A and 1B (dimensions of the rotor are shown in Table 1) and FIG. Centrifugal spraying was performed under the conditions shown in Table 2 using the conventional rotating body shown in (b).
The materials of the rotating body of the present invention shown in FIGS. 1 (a) and 1 (b) are all SUS304, and the dimensions of each part are shown in Table 1.

Table 1

Table 2 Further, the diameter of the conventional rotating body shown in FIG. 2 (b) was 100 mmφ, which is the same as the rotating body of the present invention, and the material was SUS304. After the spraying is completed, the powder is collected, classified with a 90 μm sieve, and the ratio under 90 μm is determined, which is shown in Table 3.

Table 3 In addition, Example No. 1, Example No. 3 and Comparative Example No. 1 were measured using a laser diffraction type particle size distribution measuring device, and the results are shown in FIG. From Table 3 and FIG. 6, when the rotating body of the present invention is used, it is possible to completely prevent the protrusion from the center of the rotating body and achieve good spraying.
It is understood that the lower yield is significantly improved as compared with the conventional product, and it becomes possible to obtain a powder having a sharp particle size distribution.

[0013]

EFFECTS OF THE INVENTION According to the present invention, since the kinetic energy is sufficiently imparted to the molten metal / alloy to be sprayed, it is possible to obtain a powder having a fine particle size and a sharp particle size distribution. Furthermore, since it is not necessary to accurately align the molten metal supply position with the center of the rotating body, workability is good, and powder can be mass-produced economically. In particular, it is possible to completely prevent the molten metal from jumping out from the central portion of the rotating body, so that a stable atomized state can be obtained.

[Brief description of drawings]

1 (a), (b) and (c) are views showing a rotating body of the present invention.

2 (a), (b) and (c) are diagrams showing a rotating body of a conventional centrifugal spraying device.

FIG. 3 is an explanatory diagram showing a case where a centrifugal atomization state is good in a conventional rotating body.

FIG. 4 is an explanatory diagram showing a case where a centrifugal atomization state is poor in a conventional rotating body.

FIG. 5 is an overall view of a centrifugal spraying device.

FIG. 6 is a diagram showing the results of particle size measurement in Examples.

[Explanation of symbols]

1 body part 2 side wall
3 Conical wall 4 Small room
5 Cap 6 Small room entrance
7 Komuro Exit
8 Rotating shaft 9 Double nut for cap fixing
10 molten metal 11 spray chamber
12 heating element 13 powder
14 Powder outlet
15 nozzles 16 motors

Claims (1)

(57) [Scope of utility model registration request] 1. In a centrifugal spraying device for guiding a molten metal melted to a rotating body rotating at a high speed and spraying the molten metal to produce a powder, the open surface of the rotating body is covered, and the rotating body is formed at the center of the rotating body. Separately, a cap that comes into contact with the rotating body is provided in the peripheral portion, and a cylindrical small chamber with a small hole arranged in the center of the rotating body is provided. Molten metal is poured into the small chamber from the outside, and the rotating body is passed through the small hole. And a cap, and is configured to spray from a circumferential portion of the rotating body through a gap between the rotating body and the cap.