JPH0127040Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a molten metal stirring device for melting metal by a burner in a melting chamber of a melting furnace and stirring the molten metal.

Typical prior art is, for example, Japanese Patent Publication No. 56-43374,
JP-A-55-99582, JP-A-54-41207 and JP-A-Sho
52-153802. In these prior art techniques, molten metal stored in the melting chamber of a melting furnace is drawn into an oblique or vertical riser by a vacuum source, and then a compressed gas, e.g. air,
Nitrogen, argon, etc. are supplied, and the molten metal in the riser is returned to the melting chamber of the melting furnace, thereby stirring the molten metal.

Since such prior art uses compressed gas, a means for supplying the compressed gas, such as a pressure vessel, is required. Therefore, the configuration is complicated and maintenance is troublesome. Also, when air is used as the compressed gas, the molten metal clearly oxidizes, resulting in blockage of the standpipe by oxides.

SUMMARY OF THE INVENTION An object of the present invention is to provide an improved molten metal stirring device that is simple in construction, easy to maintain, and prevents the riser from clogging.

The present invention provides a melting process having a melting chamber for melting metal to form molten metal, a burner provided in the melting chamber, and an exhaust gas discharge means for discharging exhaust gas from the melting chamber. In an apparatus for stirring molten metal for a furnace, there is provided a riser extending upwardly from the melting furnace and connected to the melting chamber below the surface of the molten metal in the melting chamber, a vacuum source, and a vacuum source connected to the riser. selectively connecting, thereby reducing the pressure in the riser and drawing molten metal from the melting chamber upwardly into the riser, and connecting said exhaust gas exhaust means to the riser in place of a vacuum source; means for returning the molten metal in the riser to the melting chamber under its own weight, including a switching valve connected to the vacuum source and the riser, the switching valve connecting the vacuum source and the riser; a first position where the vacuum source and riser are connected, and a second position where the vacuum source and riser are disconnected
said means having a valve body movable between said exhaust gas discharge means and said switching valve, said means being connected between said exhaust gas discharge means and said switching valve, said means having said valve body movable between said exhaust gas discharge means and said switching valve with said valve body in said second position; a pipe line 21 for guiding exhaust gas from the means into the riser pipe through the switching valve; a fluid pressure driving means for driving the valve body between a first position and a second position; an electric heater for heating a portion of the riser at the location reached by the drawn-in molten metal, the riser being a molten metal stirring device characterized in that the riser has an inner wall lined with a thermally insulating material. .

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention,
FIG. 2 is a horizontal sectional view thereof. A burner 2 is attached to the melting furnace 1. As a result, the ingots or scraps charged from the input preheating chambers 3, 4 are melted as indicated by reference numeral 5. This molten metal 5 is, for example, aluminum. Molten metal 5 is taken out to the outside from take-out ports 6 and 7.

A riser pipe 10 is installed near a corner of the melting furnace 1 below the surface 8 of the molten metal 5 in the melting furnace 1 . This riser 10 extends vertically outside the melting furnace 1 . At the upper end 11 of the riser pipe 10,
An inspection window 62 is provided. This upper end portion 11 is connected to a protection tank 13 via a conduit 12 . The protection tank 13 is connected to a filter 16 via a data port 14 and a valve 15 . The filter 16 is
It is connected to a three-way switching valve 18 via a conduit 17. The three-way switching valve 18 connects the pipe line 17 to the pipe line 19.
or connect line 17 to line 21 via a vacuum source 20 . Ducts 22 and 23 that guide exhaust gas from the melting furnace 1 are connected to the input preheating chambers 3 and 4. These ducts 22, 23 are led to a stack 25 via a duct 24 and vented to the atmosphere. Pipe line 21 is connected to duct 24. A portion of the molten metal 5 sucked into the riser 10 flows into the protection tank 13 via the pipe line 12 and flows into the pipe line 14.
Prevents future accidental inflow and protects subsequent equipment.

FIG. 3 is an enlarged sectional view of the riser 10.
A heat insulating material 28 is provided inside the riser pipe 10 in the radial direction.
The outside of this heat insulating material 28 is covered with a heat insulating material 29. The heat insulating material 29 is covered with an outer skin 30 made of iron or the like. An electric heater 31 is provided at the upper end of the riser pipe 10, surrounding the heat insulating material 28. This electric heater 31 is energized and heats the inner surface temperature of the portion of the heat insulating material 28 surrounded by the electric heater 31 to a temperature higher than the melting point of the molten metal, for example, 650 to 750°C. This prevents the molten metal sucked into the riser 10 from solidifying near the surface 32 where it reaches. Therefore, blockage within the riser pipe 10 is prevented.

When the pipes 17 and 19 are connected through the three-way switching valve 18, the pressure in the pipe 12 is low and the molten metal 5 in the melting furnace 1 is sucked into the riser pipe 10. The surface of this sucked molten metal 5 in the riser 10 is near the reference numeral 32, as clearly shown in FIG. Thereafter, the three-way switching valve 18 is operated to connect the pipe line 17 to the pipe line 21. Therefore, exhaust gas is guided from the duct 24 to the pipe line 12 via the pipe line 21. This exhaust gas is guided into the riser 10 as the molten metal in the riser 10 returns to the melting furnace 1 under its own weight.
Since the molten metal falls under its own weight in this way, the structure is simple. In this way, the riser 10
By returning the molten metal inside the melting furnace 1, the molten metal inside the melting furnace 1 is rotated and stirred as shown by the arrow 33 in FIG. riser pipe 1
0 is provided near the corner of the melting furnace 1, but it may be provided at other positions.

The oxygen concentration of the exhaust gas is low, so oxidation of the molten metal 5 sucked into the riser 10 is suppressed. This also allows riser 1
Blockage caused by oxides in the 0 is suppressed.

FIG. 4 is a sectional view showing a specific configuration of the three-way switching valve 18. A valve body 35 is housed in the valve box 34 . Valve rod 3 fixed to this valve body 35
6 is driven to reciprocate in its axial direction (in the vertical direction in FIG. 4) by a pneumatic cylinder 37. When the pneumatic cylinder 37 is extended and the valve body 35 is in the state shown in the fourth figure, the pipe line 17 is communicated with the pipe line 19 via the valve chamber 60. When the pneumatic cylinder 37 is contracted, thereby keeping the valve body 35 in the position indicated by the phantom line 38, the line 17
is communicated with the pipe line 21 via the valve chamber 60. Of course, this three-way switching valve 18 may be realized by other configurations.

FIG. 5 shows the pneumatic circuit of the control device 40 for controlling the pneumatic cylinder 37 that drives the three-way switching valve 18. The air pressure from the air pressure source 41 is
It is applied from the pipe line 42 to the operating valves 43 and 44. The operating valve 43 is connected to the operating valve 46. Operation valve 4
4 is connected to an operating valve 46. Air pressure from the operating valve 45 is given to a timer circuit 47. The air pressure from the timer circuit 47 and the operating valve 46 is OR
It is applied from circuit 48 and pilot line 52 as pilot pressure to spring offset type pilot actuated two-position switching valve 49. Air pressure from the air pressure source 41 is applied to one chamber 50 or the other chamber 51 of the pneumatic cylinder 37 via a conduit 61 and a switching valve 49 .

In order to automatically stir the molten metal 5 in the melting furnace 1, the operation valves 43 and 45 are operated to be in communication. As a result, the timer circuit 47 releases the supply of air pressure to the pilot line 52 for the first time W1, and supplies air pressure to the pilot line 52 for the next time W2, as shown in FIG. . In this way, the chamber 50 of the pneumatic cylinder 37 is
The pressure becomes high and the pipes 17 and 19 are connected,
Molten metal 5 is sucked into riser 10 . Also, at the next time W2, the room 51 of the pneumatic cylinder 37
becomes high pressure, the pipes 17 and 21 are communicated with each other, and exhaust gas is supplied to the riser pipe 10. For example time
W1=4 to 10 seconds, W2=2 to 4 seconds.

On-delay circuit 5 included in timer circuit 47
3 performs the operation shown in FIG. This on-delay circuit 53 is configured such that when the air pressure shown in FIG. 61 is applied to the pilot port 53a, the ports 53b and 53c are controlled at the time shown in FIG. 62.
Communication occurs after T1. When the air pressure shown in FIG. 71 is applied to the pilot port 54a, the off-delay circuit 54 shuts off the ports 54b and 54c after time T2 has elapsed as shown in FIG. 72.

When switching the switching valve 49 manually, the operation valve 44 is kept in communication, and the operation valve 46 is
cut off. Pilot line 52 is not supplied with air pressure and therefore riser 10 is connected to vacuum source 2.
It will be connected to 0. Further, if the operating valve 46 is opened while the operating valve 44 is kept in communication, air pressure is applied to the pilot pipe line 52, and the riser pipe 10
can be supplied with exhaust gas.

As described above, according to the present invention, the molten metal stored in the melting chamber of the melting furnace is selectively connected to the vacuum source via the switching valve, thereby drawing the molten metal into the riser pipe. It will be lifted up. Thereafter, exhaust gas from the burner of the melting furnace is supplied into the riser pipe through the switching valve, and the molten metal in the riser returns under its own weight into the melting chamber of the melting furnace. The exhaust gas has a low oxygen concentration, so oxidation of the molten metal is suppressed, and oxidation of the molten metal can be prevented from clogging the riser pipe.

Moreover, in the present invention, when the molten metal in the riser returns to the melting chamber, exhaust gas is drawn in. Therefore, the excellent effect of being able to smoothly discharge exhaust gas from the burner in the melting chamber is also
This will be achieved together.

Furthermore, in the present invention, an electric heater is provided in the vicinity of the position of the riser where the molten metal rises and reaches, thereby preventing the molten metal from solidifying and clogging the riser. .

Furthermore, in the present invention, the switching valve is operated by fluid pressure, so even if the switching valve is large, it can be operated relatively easily, maintenance and inspection are easy, and it can be used for a long period of time. It becomes possible to use it.

In this way, according to the present invention, an easy-to-use metal stirring device is realized which has a simple structure, is easy to maintain, and can prevent the riser pipe from clogging.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of one embodiment of the present invention, FIG. 2 is a cross-sectional view thereof, FIG. 3 is an enlarged sectional view of the riser 10, FIG. 4 is a sectional view of the three-way switching valve 18, and FIG.
The figure is a pneumatic circuit diagram of the control device 40, FIG. 6 is a waveform diagram showing the operating state of the on-delay circuit 53, and FIG.
8 is a waveform diagram showing the operating state of the off-delay circuit 54, and FIG. 8 is a waveform chart showing the operating state of the timer circuit 47. 1... Melting furnace, 5... Molten metal, 10... Rise pipe, 18... Three-way switching valve, 20... Vacuum source,
31...Electric heater, 37...Pneumatic cylinder,
40...control device.

Claims (1)

[Claims for Utility Model Registration] A melting chamber for melting metal to form molten metal, a burner provided in the melting chamber, and an exhaust gas discharge means for discharging exhaust gas from the melting chamber. an apparatus for agitating molten metal for a melting furnace, comprising: a riser extending upwardly from the melting furnace and connected to the melting chamber below the surface of the molten metal in the melting chamber; a vacuum source; is selectively connected to the riser pipe, thereby reducing the pressure in the riser pipe, drawing molten metal from the melting chamber upwardly into the riser pipe, and also connecting said exhaust gas exhaust means to the riser pipe in place of a vacuum source. means for connecting and thereby causing molten metal in the riser to return under its own weight to the melting chamber, including a switching valve connected to the vacuum source and the riser, the switching valve connecting the vacuum source to the riser; a first position where the vacuum source and the riser are connected, and a second position where the vacuum source and the riser are disconnected.
said means having a valve body movable between said exhaust gas discharge means and said switching valve, said means being connected between said exhaust gas discharge means and said switching valve, said means having said valve body movable between said exhaust gas discharge means and said switching valve with said valve body in said second position; a pipe line 21 for guiding exhaust gas from the means into the riser pipe through the switching valve; a fluid pressure driving means for driving the valve body between a first position and a second position; an electric heater for heating a portion of the riser at a position reached by the drawn-in molten metal, the riser having an inner wall lined with a heat insulating material.