JPH07233425A - Rotary degassing device - Google Patents

Abstract

PURPOSE:To provide a rotary degassing device for removing the impurities such as gaseous hydrogen, metal oxides and flux in molten aluminum, in the refining of aluminum by micronizing an inert gas injected from an impeller and discharging the micronized gas into the molten aluminum. CONSTITUTION:An inert gas such as argon and nitrogen is introduced from a gas inlet 1, passed through the gas passage piercing the rotating shaft 8 of a rotary degassing device, sent to an impeller 9 from the blowoff port of the impeller 9 and discharged into molten aluminum 13, and the aluminum is refined. In this case, the impeller 9 is formed to entrain the melt, and the inert gas is micronized and discharged into the melt. The rotating shaft 8 of the impeller is aligned with the rotating shaft of a motor with one operation, a gas passage is also provided in the rotating shaft of the motor to reduce the setting space of the motor, and the device is miniaturized.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary degassing device for removing hydrogen gas, metal oxides and inclusions such as flux contained in a molten aluminum ingot containing an alloy or the like.

[Prior Art] When an aluminum ingot, alloy, recycled metal or the like is melted to obtain a casting or an extension material, hydrogen gas, oxides, and the like, which are melted in the molten metal,
These impurities must be removed because they are affected by inclusions such as coarse intermetallic oxides or fluxes and cause defects in the aluminum material when commercialized. As a removal method, a method of blowing an inert gas into a molten aluminum through a nozzle, bringing a finely divided inert gas into contact with these impurities, and adsorbing and floating the inert gas bubbles in the molten aluminum while rising to separate and purify Has been done.

As a kind of refining apparatus which has been used conventionally, there is one shown in FIG. Gas inlet 101
Further, argon, nitrogen, or an inert gas in which chlorine gas of about 5 to 20% is mixed with them is introduced, and the rotary shaft 10 is supported by the bearing 104 via the rotary joint 102.
5 and a gas passage 106 penetrates through the central portion of a shaft 110 made of carbon ceramics connected via a joint 111, and an inert gas atomized from the tip of the impeller 108 is released into the molten aluminum 109. It is becoming like this. The shape of the impeller 108 has been variously modified so that the inert gas is molten aluminum 109.
Although it is designed to be miniaturized and emitted, there is an impeller 108 having a shape as shown in FIG. 6 as an example.

The motor 107 connects the impeller 108
A shaft 1 is provided between the rotary joint 102 and the bearing 104, the rotary shaft 105 is rotated through the belt 103, and the shaft 111 is connected to the shaft by a joint 111.
10 was rotated, and the inert gas blown into the molten metal 109 was atomized and released by the impeller 108, and impurities were separated and purified.

In such a device, a space for mounting the belt on the pulley and for rotating the pulley is required, and it is inevitable that the device becomes a large-scale device, and the rotary joint is a special-purpose rotary joint which also meets the purpose. Was required, and soaring production costs were unavoidable. Also, since the rotating shaft that rotates the impeller is connected by a joint, it is difficult to center the impeller, and it is unavoidable that eccentricity occurs in the rotation of the impeller. There was a problem that it could not be released.

[Problems to be Solved by the Invention] In the above-mentioned conventional method, it is difficult to center the rotary shaft of the impeller,
It is unavoidable that the impeller has rotational eccentricity, and it is difficult to make the bubbles fine enough. According to the present invention, by utilizing the tapered inclined surface formed by connecting the rotating shafts to each other, the axes of the rotating shafts are aligned with each other by one-touch, and the rotating shafts are screw-fixed to each other. In addition to preventing eccentricity, the shape of the impeller was also devised to subdivide the bubbles, and a gas passage was provided in the motor shaft to make the overall structure compact.

[Means for Solving the Problems] A rotary degassing apparatus based on the present invention has a gas passage provided at the center of the rotation axis of the apparatus, and refines aluminum by subdividing an inert gas from an impeller. A rotary degasser, which has a gas passage radially branched, a jetting outlet for increasing gas pressure and jetting speed, and an impeller having a plurality of openings and a suction portion at an acute angle in the peripheral portion. The rotary shaft has an upward convex taper surface and a threaded portion, and the concave taper surface and the threaded portion into which the rotary shaft is fitted allow the impeller rotary shaft to be centered in one-touch. It is desirable that the shape of the impeller subdivision chamber and the screw of the rotary shaft be formed in the reverse shape depending on the rotation direction to subdivide the inert gas.
It is also desirable to provide a gas passage in the center of the motor rotation shaft, install the motor in the center of the rotation shaft to rotate the motor, eliminate the space for installing the motor, and provide a rotary degassing device that is compact in size.

[Operation] When refining molten aluminum, an inert gas such as argon or nitrogen is blown in from a gas inlet, and a gas passage hole is passed through the rotary shaft of the motor through an ordinary rotary joint. Through the bearing box, through the tapered threaded attachment that connects the rotary shaft and the impeller rotary shaft, and the inert gas can be blown into the molten aluminum through the outlet provided in the end-mounted impeller. The gas passage was provided. When the inert gas is blown into the molten aluminum, in order to increase the blowout pressure, the outlet is made narrower and the pressure is increased to blow out into the molten aluminum, and the molten aluminum is pushed downward by the rotation of the impeller and the molten metal is rolled up. The impeller is provided with such a notch and is formed in a shape so that the blown out inert gas is subdivided and mixed into the molten metal. By using such a refining device, contact with harmful gas mixed in the molten metal was accelerated to promote refining, and the device was downsized.

[Example] An example of the present invention will be described with reference to the drawings. FIG. 1 is a structural explanatory view of a rotary degassing apparatus of an embodiment of the present invention. FIG. 2 is a sectional view of a rotary motor in the rotary degassing apparatus according to the embodiment of the present invention.
FIG. 3 is an explanatory diagram of a connection structure of a rotary shaft portion in the rotary degassing apparatus of the embodiment of the present invention. FIG. 4 is a structural explanatory view of an impeller portion in the rotary degassing apparatus of the embodiment of the present invention.

In FIG. 1, there is an ordinary rotary joint 2 having a gas inlet 1 at the top of the rotary degasser, and this rotary joint 2 is hermetically connected to the rotary shaft of a motor 4 via an attachment 3. There is. The motor 4 may be either an electric type or an air turbine type, but in the present embodiment, the electric type will be described.

FIG. 2 shows a sectional view of the motor 4. In the center of the rotary shaft 41 of the motor, a gas passage 45 for passing an inert gas for degassing passes through the rotary shaft 41 vertically. The upper part of the rotary joint 2 is air-tightly connected to the rotary joint 2 via the attachment 3 and the lower part of the rotary joint 2 is connected to the rotary shaft of the bearing box 5. The motor 4 is a normal motor having a rotor 42, a stator 43, and a motor case 44, and is different from the normal motor only in that a gas passage 45 penetrates.

At the bottom of the motor 4, there is a bearing box 5 having a gas passage 51 at the center of its rotary shaft.
The rotating shafts of the motor 4 and the bearing box 5 are hermetically connected to each other via the attachment 3 described above.
The bearing box 5 firmly supports the entire rotary degassing device, and the rotational force generated by the motor 4 rotates the impeller 9 immersed in the molten metal 13 via the impeller rotating shaft 8 described later, and the gas passage It serves to support a device for releasing the inert gas passing through 54 into the molten metal 13. Therefore, it is mounted and fixed on the base branch 7, and the base branch 7 is firmly fixed on the furnace lid 12 of the aluminum melting furnace 11.

The lower end of the rotary shaft of the bearing box 5 and the upper end of the impeller rotary shaft 8 are hermetically connected by a screw-type attachment 6 shown in FIG.

FIG. 3A shows a rotary shaft 51 of the bearing box 5, a lower end of which has a taper portion 52 for fitting with the impeller rotary shaft 8, and a screw portion 53 at the inner part thereof. The gas passage 54 penetrates the central portion. The portion opposite to this is an attachment 6 attached to the impeller rotating shaft 8 shown in FIG. 3 (B), and there is a taper portion 61 for fitting the two, and a screw portion 62 on the upper portion thereof. A gas passage 63 penetrates through the center of the. The both screw portions 53 and 62 are right-handed when the impeller 9 is rotated clockwise, and when an impeller load is applied, the attachment 6 receives an external force such that the attachment 6 is screwed into each other. As a matter of course, when the impeller 9 is rotated counterclockwise, the left screw is used.

The embodiment of the attachment 6 shown in FIG. 3 exemplifies the coupling when the impeller rotating shaft 8 is made of carbon or ceramics, but the impeller rotating shaft 8 and the attachment 6 are made of the same steel material. It does not matter if it is manufactured by using it. In that case, the attachment 6 and the impeller rotating shaft may be integrated. This attachment 6 has two tapered portions 52, 6
The surface 1 is in close contact with the gas passages 54, 63, and 10 to keep the gas airtight.

An impeller 9 shown in FIG. 4 is attached to the lower part of the impeller rotating shaft 8, which is located in the deep part of the molten aluminum 13 and is pressure-fed from the inlet 1 while being rotated by the rotating force of the motor 4. The inert gas is discharged as finely divided bubbles into the molten aluminum 13 to refine the aluminum.

The impeller 9 is a rotary body having a circular branch shape,
The inert gas that has passed through the gas passage 10 of the rotary shaft 8 is branched radially into a plurality of directions at the impeller 9 portion and is branched to the impeller internal gas passage 91. The branched gas passage 91 is discharged into the molten aluminum 13 from the ejection port 92 to a plurality of subdivision chambers 93 provided in the peripheral portion of the branch. The spout 92 in the peripheral part of the impeller 9 is
In order to increase the ejection gas pressure and ejection velocity, the gas passage 91
Is defined as a jet port 92 with a narrowed diameter.

The subdivision chamber 93 is, as shown in FIG.
The upper surface of the impeller 9 has an opening having a suction portion 94 with an acute angle, and when the impeller 9 rotates, a force to take the molten metal 13 into the subdivision chamber 93 from the opening works, so that the broken line arrow F in the figure A flow of the molten aluminum as shown in (3) appears, and the inert gas ejected from the ejection port 92 is subdivided and released into the molten metal 13. This drawing shows an embodiment of a right-handed impeller, and in the case of a left-handed impeller, its structure is a left-right inverted structure.

The operation of this embodiment will be described with reference to the drawings. 1 to 4, on the base plate 7 on the furnace lid 12 of the aluminum melting furnace 11, there is a bearing box 5 that is firmly fixed to the base branch 7, and the rotary degassing apparatus according to the present invention is provided. The rotating part is maintained. On the upper part of the bearing box 5, a motor 4 having a gas passage 45 bored at the center of its rotating shaft is placed.
An inert gas for refining aluminum, such as argon and nitrogen, is press-fitted from a gas inlet 1 via a rotary joint 2 connected to 1.

This inert gas is the bearing box 5
The gas passages 45, 54, 6 penetrating through the central portions of the rotary shafts 41, 51, 6, 8 which are rigidly supported by
3 and 10 to reach the impeller 9 immersed in the molten aluminum 13 melted at 720 to 780 ° C., pass through the radial gas passage 91 in the impeller 9, and be added from the jet port 92. It is pressurized / accelerated and released into the subdivision chamber 93 in the peripheral portion.

In order to sufficiently subdivide the air bubbles, the motor 4 is used to move the rotary shafts 41, 51, 6, 8 to about 300 to 700 r.
It is rotated at pm, and the blow-in portion 94 of the peripheral portion provided in the impeller 9 directly connected to this and the molten aluminum 13 flowing into the subdivision chamber 93 are mixed and subdivided, and an inert gas is discharged into the aluminum melt 13. Removal of impure inclusions such as hydrogen gas, metal oxides, and fluxes that are molten in aluminum.

[Advantages of the Invention] As described above in detail as the embodiments, the rotary degassing apparatus according to the present invention has various advantages.

Since the motor rotary shaft is provided with a gas passage and the rotary joint and the bearing box are directly connected to the shaft, there is no need to rotate the rotary shaft by using a pulley belt or the like. Since a rotating mechanism such as the above is not required, miniaturization can be achieved, and since a commercially available rotary joint can be used, cost town can be achieved.

Since the connection between the impeller rotary shaft and the bearing box is done by eliminating the flange connection and using the one-touch screw by the tapered surface, the rotary shaft can be easily centered and the runout of the rotary shaft is eliminated.

In the shape of an impeller, a gas ejection port and a subdivision chamber for subdividing air bubbles were provided, and a suction part was provided to forcibly circulate the molten aluminum to improve the contact between the inert gas and the molten aluminum. Therefore, the purification efficiency was improved.

[Brief description of drawings]

FIG. 1 is a structural explanatory view of a rotary degassing apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional view of a rotation motor in the rotary degassing apparatus according to the embodiment of the present invention.

FIG. 3 is an explanatory view of a connecting structure of a rotary shaft portion in the rotary degassing apparatus of the embodiment of the present invention.

FIG. 4 is a structural explanatory view of an impeller portion in the rotary degassing apparatus of the embodiment of the present invention.

FIG. 5 is an explanatory diagram of a configuration of a conventional rotary degassing device.

FIG. 6 is a structural explanatory view of an impeller in a conventional rotary degassing device.

[Explanation of symbols]

1: Gas inlet 2: Rotary joint 3: Attachment 4: Motor 5: Bearing box 6: Screw-in type attachment 7: Stand branch 8: Impeller rotating shaft 9: Impeller 10, 45, 54, 63: Gas passage 11: Furnace Wall 12: Furnace lid 13: Molten metal 52, 61: Tapered surface 53, 62: Screw part 93: Subdivision chamber 94: Suction part

Claims (3)

[Claims] 1. An inert gas is subdivided by an impeller through a gas passage in the apparatus and discharged into molten aluminum,
In a rotary degasser for purifying aluminum, a subdivision is provided with a gas passage that radially branches an inert gas, a jet port that increases the gas pressure and its jet speed, and a plurality of openings and a suction part that forms an acute angle in the periphery. It has an impeller with a chamber, a taper surface with its rotating shaft protruding, and a screw part, and an impeller rotating part that can be centered in one-touch by the concave tapered surface and the screw part of the upper rotating shaft. Characteristic rotary degassing device. 2. The rotary degassing apparatus according to claim 1, wherein the shape of the impeller subdivision chamber and the rotation shaft screw portion are formed in opposite shapes depending on the rotation direction. 3. A rotary degassing apparatus according to claim 1, wherein a gas passage is provided at the center of the motor rotating shaft to serve as a power unit to reduce the size of the apparatus.