JPH055131A - Plasma melting apparatus - Google Patents

Abstract

(57) [Summary] [Purpose] In the process of the raw material moving from the raw material charging part to the molten metal pool, it blocks the passage of large raw material in the middle of the guide cylinder, and after a small raw material passes, a large lump is put into the molten metal pool. [Problem] To provide a plasma melting apparatus configured to drop accurately [Configuration] In a raw material charging section of a plasma melting apparatus, a raw material charged from above is guided to a molten metal pool below. As described above, a guide cylinder having a hollow cylindrical shape extending toward the molten metal pool and having a downward tapered shape is provided,
Further, at the inner center position of the guide cylinder, a restricting body for restricting the passage of the raw material so as to freely move back and forth toward the lower downward opening of the guide cylinder is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma melting apparatus in which raw materials are successively supplied to a molten metal pool, and the supplied raw materials are successively melted by using a plasma torch.

[0002]

2. Description of the Related Art A conventional plasma melting apparatus includes a molten metal pool adapted to receive a charged raw material and melt it therein, a raw material charging portion located above the molten metal pool, and the above-mentioned molten metal pool. It consists of a plasma torch that is placed on the side of the upper space of the chamber and that radiates a plasma arc toward the molten metal pool.The raw material charged from the raw material charging section reaches the molten metal pool. The raw material is melted by the plasma arc.

[0003]

In the conventional plasma melting apparatus, when the raw materials are successively dropped through the raw material charging section toward the molten metal pool, the raw materials are small granular particles or large lumps. In this case, the raw material was scattered outside the molten metal pool in the process of being dropped toward the molten metal pool, or even if the raw material fell into the molten metal, there was a risk that part of the molten metal would fly out of the molten metal pool due to the force.

The present invention has been made in order to solve the above-mentioned problems (technical problems) of the prior art. In the process in which the raw material moves from the raw material charging portion to the molten metal pool, a large raw material It is an object of the present invention to provide a plasma melting apparatus configured to prevent passage of a small raw material and to drop a large lump accurately into a molten metal pool after passing a small raw material.

[0005]

In order to achieve the above object, a plasma melting apparatus according to the present invention includes a molten metal pool for receiving a charged raw material and melting it therein, and a molten metal pool of the molten metal pool. It comprises a raw material charging section located above and a plasma torch which is placed on the side of the space above the molten metal pool and radiates a plasma arc toward the molten metal pool. In the plasma melting apparatus in which the raw material charged from the inlet is brought to the molten metal pool and the raw material is melted by the plasma arc, the raw material charged from above is guided in the raw material charging portion. And a guide cylinder having a downward tapered shape that extends toward the above-mentioned molten metal pool toward the molten metal pool below. In a central position are those which gave comprising a limiter for limiting the passage of freely feed the advance and retreat toward the bottom tapering shape of the lower opening of the guide tube.

[0006]

[Function] Among the falling raw materials, the large raw material is temporarily prevented from descending between the inner surface of the guide cylinder and the restricting body, and the large raw material is directed from the position where it stopped to the small raw material in the molten metal pool. Can be lowered slowly.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. The illustrated plasma melting apparatus includes a raw material supply facility A, a plasma melting apparatus B, and a casting apparatus C. First, in the raw material supply facility A, the bucket conveyor 11 has thirteen buckets 12. After receiving the raw material weighed by a weighing device (not shown) into the bucket 12, the bucket conveyor 11 receives the raw material.
Carry to 13. A drum feeder 15, which is used as a raw material supply device, is provided on a frame 14 constructed next to the conveyor. This drum feeder
Two fifteen are provided side by side in parallel (the other is hidden behind what is shown in FIG. 1). A charging port 16 is provided at one end of each drum feeder 15 so that the raw material can be received from the hopper 13. The charging port 16 is closed by a door when the raw materials are not charged. A chute 17 is connected to the other end of the drum feeder 15.

Next, in the plasma melting apparatus B, a melting chamber 20 is fixed to the frame 14 at a position below the drum feeder 15. The melting chamber 20 is configured so that the inside can be hermetically sealed, and a raw material charging portion 21 is provided in the upper central portion. The upper part of the charging part 21 is covered with an airtight surrounding part 22 so that the melting chamber 20 can be kept in a sealed state. The chute 17 communicates with the airtight surrounding portion 22. On the other hand, below the charging part 21, a guide cylinder 23 integrally formed with the airtight surrounding part 22 hangs down, and the raw material charged from the chute 17 toward the charging part 21 is guided by the guide cylinder 23. After that, it falls into the center of the crucible, which will be described later. Six plasma torches 24 are attached to the melting chamber 20 around the charging portion 21. These plasma torches 24 are 60
The cathodes of the respective interiors are mounted at intervals of one degree and are connected to the negative terminal of the dedicated DC power supply. A supporting rod 25 is provided below the melting chamber 20 so as to freely move back and forth in FIG. An arcing piece 26 is attached to the tip of the supporting rod 25.
Is installed. The rear end of the support rod 25 is connected to the advancing / retreating device 27 so that the support rod 25 can move in the above-mentioned direction.

Next, the casting apparatus C is provided inside the pit 31. A support arm 32 is provided at the bottom of the pit 31,
A rail 33 is provided on the upper portion of the rail 33 in a direction perpendicular to the paper surface in FIG. The dolly 34 has wheels 34a and can move along the rails 33. Trolley
A hydraulic jack 35 is attached to 34, and an ingot chamber 36 is attached to its piston rod via a bracket 35a. A crucible 37 is provided in the upper portion of the ingot chamber 36, and the crucible 37 is fitted in a through hole formed in the lower portion of the melting chamber 20. As is well known, the crucible 37 forms a molten metal pool therein. An ingot lowering device 38 is provided inside the ingot chamber 36. The pulling-down device 38 has a multi-stage cylinder. A stub clamp 39 is provided at the upper end of the pulling device 38, and a stub 40 that constitutes the crucible bottom inside the crucible 37 is attached thereto, and the stub clamp 39 has a power supply terminal for supplying power to the stub. It is provided so that it can be connected to the positive terminal of the DC power supply of each plasma torch.

Next, FIG. 2 showing the details of the plasma melting apparatus B.
In the melting chamber 20, the molten metal pool 37a in the crucible 37 is
It is configured by a hollow furnace wall 50 that surrounds the upper space of the. The furnace wall is composed of a lower furnace wall 51 and an upper furnace wall 52. Both furnace walls 51 and 52 have a water cooling structure as is well known. A connecting member 53 is provided at a connecting portion between an upper portion of the lower furnace wall 51 and a lower portion of the upper furnace wall 52, and the furnace wall 50
Gas is not allowed to flow between the inside and the outside. Next, the airtight surrounding portion 22 includes a tubular portion 54 and a plate 55 closing the upper end thereof. An inspection port 56 and a raw material feeding port 57 are provided on the side wall of the cylindrical portion 54. The chute 7 is provided at the inlet 57.
A pipe 57a communicating with is provided. Further, the connecting portion between the lower portion of the tubular portion 54 and the upper portion of the upper furnace wall 52 is configured by using a connecting member 58. Next, the guide cylinder 23 is also called a raw material storage tank, and is composed of an upper guide cylinder 59 having a right cylindrical shape and a lower guide cylinder 60 having a taper shape continuous with the lower end thereof. The inner surface of the lower guide tube 60 is lined with titanium 61
Is provided. The airtight enclosure 22 and the guide tube 23
Are integrally formed as described above, and they are constructed in a water cooling structure as is well known. Next, a cylindrical body 67 fixed to the plate 55 is provided in a hanging shape at the axial center positions of the cylindrical portion 54 and the upper guide cylinder 59. This cylinder 67 is covered with titanium. At the bottom of the tubular body 67, a limiting body 68 made of titanium and having a tubular shape is provided. It is attached to the lower end of an elevating cylinder 69 that is vertically movable in the restricting body 68 and the cylindrical body 67.
An inner cylinder 70 is inserted into the restricting body 68 and the elevating cylinder 69, and they have a double pipe structure. Further, a water supply port 71 and a drain port 72 are provided on the upper part of the elevating cylinder 69. The cooling water sent from the water supply port 71 is supplied to the inner cylinder 70, the restriction body 68, and the elevating cylinder.
After being circulated inside 69 as shown by the arrow to cool them, the water is discharged from the drainage port 72. A support frame 73 is attached to the plate 55, and an elevating cylinder is attached to the upper portion thereof. The piston rod of the cylinder is connected to the elevating cylinder 69 via a connecting member 76, and the limiting body 68 can be moved up and down by the operation of the cylinder. In the present specification, the cylinder, the elevating cylinder 69, etc. are also referred to as elevating means for the restricting body 68. Next, the plasma torch 24 is electrically insulated and attached to the upper furnace wall 52 by using a well-known torch attachment 62. On the other hand, in the lower part of the melting chamber 20, the arcing piece 26 is attached to the supporting rod 25 by using a bracket 63, and in the present specification, this combination is also called an ignition rod. In addition, this arcing piece 26 has a storage chamber 64 formed in a part of the lower furnace wall 51 when the support rod 25 moves to the right in the figure.
It is designed to be stored inside. On the other hand, a magnetic field generation coil 78 for deflecting the plasma arc emitted from the plasma torch 24 is provided around the crucible 37 as is well known.

Next, FIGS. 3 and 4 show a state in which a raw material is charged into the melting chamber 20 and melted by an arc from a plasma torch. The operation in that case will be described below. First, normally, the limiting body 68 is lowered by the lifting cylinder, and the lower end thereof faces the lower opening 60a of the lower guide cylinder 60. In this case the opening
Between the inner surface of 60a and the outer surface of the restricting body 68 is a fine-grained or sponge-like titanium raw material (the size is, for example, 3 mm to 20 mm).
There is an interval of 149 that can pass through. In this state, a small titanium raw material 150 such as a sponge-like or fine granular material of the raw material fed from the drum feeder through the chute 17 and the feeding port 57 toward the charging portion 21 is a lower guide tube 60. Is guided toward the center of the melting chamber (the center of the crucible) by means of the melting chamber 37, and passes through the space 149.
It is charged toward the center of the molten metal pool 37a. On the other hand, large titanium raw material 151 such as scrap of raw material sent to the charging section 21 cannot pass through the interval 149, and as shown in FIG. It is sandwiched between and stops there. If the large-sized raw material 151 stops at the above-mentioned place, the small-sized titanium raw material 150 is allowed to drop toward the molten metal pool 37a for a while, and then the restricting member 68 as shown in FIG. And the large-sized raw material 151 is dropped toward the molten metal pool in the crucible. In this case, as described above, the small-sized raw material 150 is first dropped toward the center of the molten metal pool 37a in the crucible 37, and the small-sized raw material is accumulated in the molten metal pool 37a. 151 ingredients are dropped. Therefore, the small-sized raw material that has been dropped first and accumulated in the center of the molten metal pool serves as a cushioning material, and the impact of the drop of the large-sized raw material 151 is mitigated. Thus, even when a large-sized raw material is charged, the molten metal is prevented from scattering due to the control of the falling speed by the action of the limiting body 68 and the buffering effect of the small-sized raw material. The size of the interval 149 can be variously set by appropriately selecting the height at which the limiting body 68 is located. As a result, as described above, the size of the raw material temporarily stopped in the guide cylinder 60 can be variously selected.
Further, as described above, since the restricting body 68 is in the melting chamber 20 and the large-sized raw material can be temporarily stopped at a position relatively close to the crucible and then dropped into the crucible, the crucible falls outside the crucible. In addition, it is possible to prevent the small raw material 150 from being damaged, and when the small raw material 150 is put in advance and the large raw material 151 is put thereon, the large raw material 151 is prevented from directly falling into the molten metal in the crucible. It is prevented that the molten metal overflows on the crucible and that the splashes adhere to the torch 24 and damage it.

[0012]

As described above, in the present invention, since the plasma torch 24 is arranged so that the raw material placed on the surface of the molten metal pool 37a can be heated by the plasma arc,
There is an effect that the raw materials supplied one after another onto the molten metal pool can be melted one after another.

In addition, when the raw material is supplied to the molten metal pool 37a, the raw material is guided by using the guide tube 23, so that the raw material accurately drops toward the molten metal pool, and unnecessary scattering occurs. There is also an effect that can be prevented.

In particular, in the present invention, since the restricting body 68 is simply movable up and down, the structure has the feature that it can be simplified, and in addition to providing a structure with few failures, it is a breakthrough. Have a positive effect. Moreover, even with a simple structure in which a failure is unlikely to occur, simply moving the restricting body 68 up and down will guide the guide tube.
It is possible to prevent the large raw material from descending between the 23 and the restriction body 68. This allows the passage of small raw materials, but temporarily blocks the passage of large raw materials, and then allows the lowering of large raw materials as necessary. Alternatively, depending on the state of melting, in some cases the mixed raw materials of large and small sizes are lowered onto the molten metal pool, and in some cases only the small raw materials and in some cases the large raw materials are once received by the buffer piece and the descent force is relaxed. It has an excellent effect that the descending state can be controlled as desired by directing it to the molten metal pool.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional view of a melting and casting apparatus.

FIG. 2 is a vertical sectional view of a melting device.

FIG. 3 is a vertical sectional view of a melting chamber.

FIG. 4 is a vertical cross-sectional view showing the relationship between the restriction body and the molten metal pool.

[Explanation of symbols]

 20 Melting chamber 21 Raw material charging section 23 Guide tube 24 Plasma torch 37a Molten metal pool 68 Restricted body

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Hiroyuki Yamada 131, Nishichimaru Nishinomaru-cho, Konan-shi (72) Inventor Yasuo Watanabe 1-908 Nishinodai, Chita-shi

Claims (1)

Claim: What is claimed is: 1. A molten metal pool adapted to receive a charged raw material and dissolve it therein, a raw material charging portion located above the molten metal pool, and the molten metal pool. It consists of a plasma torch that is placed on the side of the upper space and that radiates a plasma arc toward the molten metal pool, and reaches the molten metal pool from the raw material charged from the raw material charging section. In the plasma melting apparatus which is adapted to melt the raw material by the plasma arc,
The raw material charging portion is provided with a guide cylinder having a hollow cylindrical shape and a downward tapered shape extending toward the molten metal pool so as to guide the raw material charged from the upper side toward the molten metal pool below. In addition, at the inner center position of the guide cylinder, a restricting body for restricting the passage of the raw material to freely move back and forth toward the downward narrowed opening of the guide cylinder is provided. Plasma melting device.