JPH0211704A - Method and apparatus for producing atomized powder - Google Patents

Abstract

PURPOSE:To eliminate water disturbance of liquid coolant caused by liquid jet for atomizing molten metal and to produce metal powder having narrow particle size distribution and uniform particle size at high yield by giving the liquid coolant in an atomizing vessel the horizontal rotating movement at the time of pulverizing by atomizing molten material of the metal, etc., with the liquid jet. CONSTITUTION:The metal, alloy or ceramic is melted in a melting furnace 1 and flowed down into the atomizing vessel 6 containing the liquid coolant 7 as molten material stream 3 from a bottom nozzle. By blowing the liquid jet 5 to the molten material stream 3 from the atomizing device 4, it is pulverized, and by blowing the liquid coolant 7 in the atomizing vessel 6, it is solidified to produce the powdery body of the metal or the ceramic. In this case, by injecting water to horizontal direction from a tangential blowing hole 25 against the liquid coolant 7 in the atomizing vessel 6, the horizontal rotating movement is given to the liquid coolant 7 to form vortex flow 51 and the liquid coolant 5 is collided to deep part at center of the vortex flow 51. The atomizing of the molten material stream 3 caused by the disturbance of the cooling water 7 with the liquid jet 5 does not become unstable, and the atomized powder of the metal or the ceramic having uniform particle size is obtd.

Description

[Detailed Description of the Invention] [Industrial Application Field 1] The present invention relates to a method of manufacturing atomized powder and an apparatus thereof, and is a method for manufacturing various mechanical parts and products by molding and sintering metal powder or ceramics. Regarding manufacturing technology of raw material fine powder.

[Prior Art] FIG. 4 shows a typical example of a conventional atomized fine powder manufacturing technology.

A molten metal or ceramic 2 is stored in a melting furnace 1 consisting of a furnace body 1a, a stopper 1b, a high-frequency heating coil lc, and a molten metal nozzle 1d, and a falling molten metal stream 3 is suspended from the molten metal nozzle ld. On the other hand, the water (or other liquid such as oil) spraying device 4 includes a liquid inlet 4a, an annular liquid nozzle 4
b. A circumferential tank 4C is provided to equalize the pressure, and the spray liquid (liquid jet) 5 is sprayed in an inverted conical shape.

For that cone! ! In the vicinity of 3.3, the molten metal downstream 3 is subjected to liquid collision and cooling, and becomes powder. The liquid and powder mix to form a downwardly expanding portion, ie, a diffusion jet 5a, which spreads out in a substantially conical shape, and falls into the spray tank 6. The spray tank 6 stores a liquid 7 and cushions the impact of the diffusion jet 5a and cools it. The liquid in the diffusion jet 5a still has a considerable speed, and the atmospheric gas 7e is also drawn in, causing the surface of the liquid 7 to swing greatly as shown at 7a and 7b. At this time, a part of the liquid 7 becomes large droplets 7c or lumps 7d and rises (hereinafter this phenomenon is referred to as water rampage), which hits the liquid jet 5 and makes the spray unstable.

As a result, the shape of the resulting powder is irregular, the size does not converge into a narrow particle size range, but has a wide distribution, and sieving is required during use, which leads to a decrease in yield contrary to the intention of obtaining a homogeneous product by liquid atomization. I was invited.

To prevent water damage as a remedy for this problem.

As shown in FIG. 5 or 6, obstacles 11 and 12 that impede the movement of the liquid were placed in the liquid, and some results were obtained. However, these obstacles 11 and 12 are subject to severe wear due to collisions with powder-containing liquid jets, require a great deal of effort to replace, and are still insufficient in that they are unable to sufficiently suppress water surges. there were.

[Problems to be Solved by the Invention] The best way to prevent water turbulence is to prevent the liquid storage 7 from reacting due to the impact of the liquid jet. For this purpose, for example, when the liquid jet collides with the liquid storage 7, the angle of intersection with the liquid surface should be made as small as possible from 90 degrees, and if possible, it is desirable that the surface of the liquid storage 7 be nearly parallel to the direction of the liquid jet. . Furthermore, if the bubbles of the atmospheric gas brought in by the liquid jet do not rise above the stored liquid and are carried away downward, disturbances caused by the bubbles can be eliminated.

The present invention aims to reduce water turbulence in atomized powder production technology in which powder is produced by colliding a pressure fluid with a molten metal stream flowing down from such a nozzle, and the powder is cooled in a spray tank containing liquid. The objective is to prevent this problem and obtain atomized powder with uniform particle size.

[Means for Solving the Problems] The technical means of the present invention for solving the above problems is to apply a horizontal rotational flow to the liquid in the spray tank to make the liquid surface depressed, and to cause the powder generated in the depression to fall. This is a method for producing atomized powder characterized by the following.

Furthermore, the apparatus of the present invention for carrying out this method is a liquid atomization apparatus for producing powder from a dripping molten metal flow by means of a high-pressure liquid, and the apparatus is a liquid atomization apparatus that produces powder from a dripping molten metal flow using a high-pressure liquid. , is an atomized powder production device characterized by having a liquid or gas inlet that gives a horizontally rotating flow to the liquid in the tank, and also has a method for horizontally rotating the liquid in the spray tank to raise the liquid level. It is also possible to use a device in which a recessed rotor is provided within the spray tank.

[Effect 1: When horizontal rotation is applied to the liquid in the liquid spray tank, a vortex is created, and a liquid-free space is formed in the upper center of the vortex, and the liquid jet that has generated the powder is deep in the vortex 51 to form a vortex. corresponds to

As a result, the collision resistance between the liquid jet and the liquid in the spray tank is eliminated, and water swell is eliminated.

Therefore, liquid jet spraying is stable, and powder with a narrow particle size range and well-shaped powder can be obtained.

〔Example〕

The present invention will be described in detail with reference to FIGS. 1 to 3.

The molten metal stream 3 flowing down from the melting furnace 1 is led to an annular water spray device 4, is pulverized by an inverted conical liquid jet 5, becomes a diffusion jet 5a together with water, and falls into a spray tank 6. The liquid 7 stored in the spray tank 6 is given a horizontal rotational flow to form a depression in its liquid level. In this embodiment, this recess extends from the pump 21 to the electric valve 22 to the distribution ring 23.
, an electric flow control valve 24, and a tangential inlet 25.

In FIG. 1, the blown liquid is introduced tangentially into the spray tank 6 from the two injection ports 25, but as a result, the liquid stored in the tank rotates and creates a vortex as shown in FIG. A space with no liquid storage is formed above the center, and the diffusion jet 5a is connected to the second
As shown in the figure, the deep part of the vortex envelope surface 51 hits the liquid storage 7. Therefore, there is no direct collision between the diffusion jet 5a and the stored liquid 7, and the water surge is eliminated.

Furthermore, in this embodiment, the circulation pump 21 rotates the stored liquid and the stored liquid is continuously discharged from the outlet 6a at the bottom of the spray tank, so that this flow causes the vortex depression to extend downward. The shape of the vortex envelope surface 51 of the liquid surface formed by the vortex can be adjusted by a control valve 6b that regulates the inflow speed of the blown liquid from the inlet 25 and the amount of discharge from the outlet 6a. Further, due to this downward flow of liquid, the generated powder is immediately discharged from the spray tank, and continuous automatic powder collection is enabled by the cyclone 31, cascade settling tank 32, final filtration device 33, and liquid cooling device 34. Therefore, conventionally, powder was stored in the spray tank 6 and banding was performed every fixed amount.
In contrast, it is possible to achieve a labor-saving effect in the spray tank.

Of course, configuring the discharge of the stored liquid in this way and circulating the liquid in this manner are independent of the present invention, and the storage liquid may be rotated by gas or rotary blades, etc., and these means may be used depending on the situation. It is advisable to adopt it according to the situation.

It should be noted that the configuration of this embodiment does not preclude similar changes and applications. For example, the tangential inlet 25 for liquid into the spray tank 6 is not provided at two locations as shown in FIG.
It goes without saying that the number may be 4, 6.8 or more.

Furthermore, as shown in FIG.
It is also possible to set the incident angle to an arbitrary angle such as 20 degrees or 20 degrees, and make the shape of the depression steep.

Further, although it is desirable that the cross-sectional shape of the spray tank 6 is circular, it does not necessarily have to be circular, and the effect of the present invention will not change in any way as long as the vortex can be formed into a trumpet-shaped depression. Further, the present invention can be applied not only to metal powder but also to other powders such as ceramic powder and polymer powder.

[Effect of the invention] As a result of the liquid surface being hit by a liquid jet in a conventional spray tank, there is a large unsteady liquid fluctuation and a water turbulence accompanied by upward splashing and scattering. Jinshomono structures have been proposed, but they are all complicated, require troublesome maintenance, including construction and cleaning, and are not completely effective.

The present invention can moderate and cool the jet flow without placing any structure in the tank, so there is no need to worry about powder staying in the corners of the structure or solidifying, and the swirling flow This prevents powder from adhering to the inner wall of the spray tank, the tank interior is easy to clean, and there is no splashing of liquid, resulting in stable liquid jet spraying. Furthermore, continuous discharge of slurry containing powder and liquid cooling can be easily automated as a closed system.

[Brief explanation of the drawing]

Fig. 1 is an overall configuration diagram of an atomizing device according to an embodiment of the present invention, Figs. 2 and 3 are explanatory diagrams of the intersection of a vortex and a liquid jet, and Fig. 4 is an illustration of the structure and function of a conventional atomizing device. The explanatory drawings, FIG. 5, and FIG. 6 are perspective views showing examples of conventional water splash prevention devices. 1... Melting furnace 2-... Molten metal 3...- Molten metal flow 4... Liquid spray device 5-... Liquid jet 6... Spray tank 7-... Liquid storage 51-... Eddy current envelope surface 11 .12...Water rampage prevention device

Claims (1)

[Scope of Claims] 1. In the production of atomized powder, a powder is generated by colliding a molten metal stream flowing down from a nozzle with a pressure fluid, and the powder is cooled in a spray tank storing liquid, the spray tank A method for producing atomized powder, characterized by applying a horizontal rotational flow to the liquid in the container to make the liquid surface concave, and causing the generated powder to fall into the concavity. 2. In an atomization device that produces powder from a dripping molten metal flow using a high-pressure fluid, a liquid or gas that provides a horizontal rotational flow to the liquid in the spray tank in the tangential direction of the circumference of the spray tank that stores the liquid that cools the powder. An atomized powder manufacturing device characterized by being equipped with an inlet. 3. An atomized powder manufacturing apparatus characterized in that a rotary blade is provided in the spray tank to apply horizontal rotation to the liquid stored in the spray tank to make the liquid surface depressed.