JPH0238877B2 - KINZOKUYOTOKAKUHANSOCHINIOKERUMETARUHISANBOSHIHOHO - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for preventing metal scattering in a molten metal stirring device.

In a metal melting furnace for aluminum, copper, zinc, etc., if the molten metal is not stirred, the melting time becomes longer and the temperature at which the molten metal surface must be heated becomes higher. As a result, various drawbacks such as an increase in the amount of oxides generated occur, which is known to be a factor in low quality and high costs. In order to suppress oxidation phenomena and obtain high quality products, it is required to lower the heating temperature and shorten the time required for melting. For this purpose, stirring the molten metal is of great help. In the case of aluminum, stirring reduces both the amount of oxides generated and the melting time by about 10%, but the current situation is that the remaining 90% of oxides cannot be stopped from being generated.

As shown in FIG. 1, a conventionally well-known mechanical stirring device for performing effective stirring work includes a refractory intermediate body 3 with communicating holes 2 provided in the lower part of the side wall of a melting furnace 1. A pump cylinder 4 whose inner wall is lined with a fireproof material is attached to the intermediate body 3. The pump cylinder 4 and the inner bottom of the melting furnace 1 are communicated through the communication hole 2, and a ventilation pipe 8 is provided with an automatic switching valve 5 between outside air and negative pressure, a cyclone 6, a filter 7, etc. The upper part of the pump cylinder 4 and the vacuum blower 9 are connected. The vacuum blower 9 is operated by a motor 10 to operate the pump cylinder 4 to a vacuum pressure to draw the molten metal into the cylinder 4, and after a certain period of time has passed, the automatic switching valve 5 is switched to introduce outside air. Since the vacuum suction force is removed and outside air is introduced, the molten metal sucked up into the pump cylinder 4 returns to the melting furnace 1 by its own weight, causing convection in the accumulated molten metal and stirring the inside of the melting furnace 1.
After this stirring work is completed, the hot water is tapped to complete one cycle of work steps. However, in the next work cycle, the material is charged into the melting furnace 1, heated and melted,
When starting the stirring work, the cylinder 4 is opened with the molten metal water level in the furnace down to the communication hole 2 at the bottom of the cylinder.
When suction is performed, metal oxides and air on the surface of the melting furnace 1 are sucked together with the molten metal.
Usually, the cylinder 4 of the molten metal 11 is sucked in for stirring.
The water level 14 in the cylinder is approximately at a fixed position, but when the metal oxide and air are sucked together as described above, the air containing the metal oxide is lighter than the molten metal, so it blows up strongly above the fixed water level 14, and the cylinder 4. Metal powder is scattered on the upper part of the inside of the ventilation pipe 8.
Adheres to the area near the entrance/exit 15 and solidifies, causing the entrance/exit 15
may become obstructed. If the inlet/outlet 15 is blocked, the vent pipe 8 will be of no practical use unless it is disassembled, cleaned and reassembled, so the molten metal stirring device 1 cannot be used during that time.

The present invention has been made to solve the above problems, and the vent hole of the cylinder that sucks in and discharges the molten metal is not blocked by the metal oxide generated during stirring in the melting furnace. , the purpose of which is to provide a method for preventing metal scattering in a molten metal stirring device that enables continuous use of the molten metal stirring device, and the molten metal is periodically vacuumed from the melting furnace into the cylinder. The molten metal stirring device is characterized in that a metal sensor is installed in the upper part of the cylinder 4, and the detection signal of this metal sensor is linked to the opening and closing of the automatic switching valve 5 and the opening and closing of the motor switch. .

Next, embodiments of the present invention will be described with reference to the drawings. In this embodiment, a metal sensor 13 is installed inside the cylinder 4 as shown in FIG. 2 near the entrance/exit 15 of the vent pipe 8 provided at the top of the cylinder 4 in the conventional molten metal stirring apparatus shown in FIG. It was established. As shown in FIG. 3, the metal sensor 13 has a metal tube 16 with an arcuate cross section erected on a metal disk 21 to serve as a negative electrode, and a metal column 17 is installed at the center of the tube 16. Insulator 20 at the terminal of
This is a positive electrode that is erected through the electrode.

With the above configuration, in this embodiment, when the water level of the molten metal in the melting furnace 1 has fallen to the communication hole 2 at the bottom of the cylinder and suction into the cylinder 4 is performed, the vacuum pressure in the cylinder 4 is reduced. As a result, the air containing the metal oxide is blown upward from the normal molten metal level 14, and the aluminum powder is scattered, and when it adheres to the metal sensor 13, the positive and negative electrodes 16 and 17 are short-circuited. This short-circuit signal closes a switch (not shown) of the motor 10, and at the same time switches the automatic switching valve 5 to immediately introduce outside air pressure to the vent pipe 8 in order to bring the vacuum pressure in the cylinder 4 to zero and stop subsequent suction. It is possible to prevent the inlet/outlet 15 from being blocked by metal powder adhesion and solidification.

As described above, the present invention can prevent the metal powder from clogging the ventilation pipe due to suction into the cylinder when the water level of the molten metal in the melting furnace has fallen below the communication hole at the bottom of the cylinder. Of course, the same effect can be obtained not only in the case of copper, zinc, etc. Further, if the entrance/exit port 15 is blocked by metal oxide, the cylinder must be cleaned due to the suspension of stirring work for a long time, resulting in a large loss. Therefore, the method for preventing metal scattering according to the present invention greatly contributes to the effective operation of

[Brief explanation of drawings]

FIG. 1 shows a schematic configuration of a conventional aluminum metal molten metal stirring device, FIG. 2 is a sectional view showing a schematic configuration inside a cylinder according to an embodiment of the present invention, FIG. 3a is a front view of a metal sensor, and FIG. FIG. 3b is a plan view of the same. DESCRIPTION OF SYMBOLS 1... Metal melting furnace, 2... Communication hole, 3... Intermediate, 4... Cylinder, 5... Automatic switching valve, 6
...Cyclone, 7...Filter, 8...Vent pipe, 9...Vacuum blower, 10...Motor, 11
... Aluminum molten metal, 12 ... Aluminum oxide, 12' ... Aluminum oxide inside the cylinder, 13 ... Metal sensor, 14 ... Suction aluminum molten metal water level during normal operation, 15 ... Inlet/exit to vent pipe 8 , 16...metal sensor negative electrode, 17
...Metal sensor positive electrode, 18, 19...Metal sensor detection signal output terminal, 20...Insulator, 21...
...Metal disk.

Claims (1)

[Claims] 1 In a molten metal agitation device that periodically sucks molten metal in a melting furnace into a cylinder by evacuating the cylinder and discharges the molten metal into the furnace, a metal powder is formed in an upper part of the cylinder. Built-in metal sensor with both poles that short-circuit
When the molten metal surface in the melting furnace is lower than the cylinder suction port, the metal powder sucked into the cylinder short-circuits both poles of the metal sensor, and the short-circuit signal of the metal sensor poles causes
A metal molten metal stirring device characterized in that an automatic switching valve for switching between outside air and vacuum pressure to the cylinder is switched to the outside air side, and a motor circuit is opened to drive a vacuum blower that generates vacuum pressure to the cylinder. How to prevent scattering.