JPH0120356B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a non-ferrous metal molten metal holding device.

(Prior art and problems) Conventionally, crucible-type melting and holding furnaces such as graphite crucibles or iron crucibles for non-ferrous metals such as aluminum, zinc, and their alloys have been operated using an external indirect heating method using heavy oil, gas, etc. as a heat source. General. However, from the viewpoint of reducing fuel costs in product prices and improving quality, holding furnaces that use electricity as a heating source have come to be used instead of these crucibles (for example, as described in Japanese Patent Publication No. 38342 of 1982). ). In this case, it is not possible to use a so-called external heating method in which the furnace is heated from outside the furnace. Therefore, the molten metal can be heated by indirect heating from the surface of the molten metal or by direct heating by immersing an electric heater into the molten metal.
However, in the case of surface heating, when the molten metal is being pumped out, the molten metal may come into contact with an electric heater installed on the ceiling away from the surface of the molten metal, or when the material is being added, it may come into contact with the electric heater. There is a problem that oxides (ghosts) that have grown on the furnace wall come into contact with the electric heater and shoot out, damaging the electric heater and causing sudden accidents that make the electric heater unusable. Since the terminals of the electric heater must be located outside the furnace, it is necessary to sufficiently seal the space between the electric heater and the furnace wall to prevent molten metal from leaking. The reality is that it is difficult to complete this seal and the sealing operation cannot be performed quickly. In any case,
Heating with an electric heater cannot apply a sudden heat load compared to heating with external heating type heavy oil or gas. Therefore, when handling a large amount of molten metal or when raising the temperature in a short time, it is necessary to increase the number of electric heaters in one furnace. As the number of electric heaters increases, the amount of labor and expense spent on the electric heaters increases accordingly. The present invention eliminates the various drawbacks of the conventional method by employing a direct heating method in which a radiant heating element using gaseous fuel is charged into the molten metal. Examples will be described in detail below.

(Structure and operation) Reference numeral 1 indicates a heating body, and this heating body has the following configuration. That is, a flame holding section 3 is provided on one side of the inner tube 2, an outer tube 4 is provided outside the inner tube 2, and a heat exchanger between combustion air and exhaust gas is provided upstream of the flame holding section 3. This is a configuration in which a section is provided. The heating body 1 having such a structure is inserted into the molten metal holding furnace 6. Reference numeral 11 denotes a fireproof partition wall provided on both sides of the heating element 1, and the partition wall 11 allows the pouring chamber 12,
A heating chamber 13 and a pumping chamber 14 are configured. The refractory partition wall 11 does not reach the bottom of the furnace, but is configured to communicate with the chambers 12, 13, and 14 below. The fireproof partition wall 11 has the function of protecting the heating element 11 when pouring molten metal into the pouring chamber 12, and
Since the pumping chamber 14 is on the opposite side from the pouring chamber 12,
During pumping, impurities such as oxides are not removed. That is, a purifying effect can be achieved and the quality of the product can be improved. FIG. 2 shows another embodiment of a graphite crucible 1 having a pouring and drawing outlet 19.
5 is placed on a stand 18 inside a container 17 made of a heat insulating material 16, and a heating element 1 is provided inside the crucible 15. In this case, since the crucible 15 is not directly heated by a burner as in the conventional case, the refractory life of the crucible 15 can be greatly improved. Therefore, the gas introduced from the gas introduction part 7 and the air introduced from the air introduction part 8 are partially mixed in the flame holding part 3, and combustion is continued in the inner tube 2 while holding the flame. do. A portion of the combustion gas flows through a small hole 9 provided in the inner pipe 2.
Most of the combustion air exits the outer tube 4 from the tip of the inner tube 2 and returns to the exhaust heat recovery section 5, where it exchanges heat with the combustion air introduced from the air introduction section 8. be discharged. In this flow of combustion gas, combustion heat is transferred to the outer tube 4 and heats the molten metal 10. It is preferable that the outer tube 4 has no reactivity with the molten metal 10 and is durable. For example, a material made of silicon carbide or silicon nitride is suitable. It is desirable that the heating element 1 can be configured to be movable and replaceable.

(Effects of the Invention) Since the present invention is as described above, it has the following advantages. Since it uses the heating element described above, it is capable of high-load combustion, has a large temperature-raising capacity, has high thermal efficiency, and can heat a large amount of molten metal in a short time, offering outstanding workability. . Therefore, the number of heating elements installed in the furnace can be extremely reduced.
Since the above-mentioned heating element is used, there is an advantage that the heating element can be replaced as if replacing a single rod, and there is no fear of leakage of molten metal as with electric heaters. Since combustion energy is used effectively, compared to electrical energy,
It is much more energy efficient. When a graphite crucible is used as a melting and holding furnace, the life of the graphite crucible can be significantly improved compared to the conventional external heating type.
When fireproof partition walls are provided on both sides of the heating element, there are excellent advantages as described above, such as protection of the heating element and improvement in the quality of the molten metal pumped out.

[Brief explanation of drawings]

1 and 2 are explanatory diagrams of the present invention. Reference numerals 1... Heating body, 2... Inner tube, 3... Flame stabilizing section, 4... Outer tube, 5... Exhaust heat recovery section, 6... Molten metal holding furnace, 7... Gas introduction section, 8... ...Air introduction part,
9... Small hole, 10... Molten metal, 11... Fireproof partition wall, 12... Pouring chamber, 13... Heating chamber, 14...
Pumping chamber, 15...graphite crucible, 16...insulation material,
17... Crucible stand, 18... Pouring and pumping outlet.

Claims (1)

[Claims] 1. A flame stabilizing section is provided on one side of the inner tube, an outer tube is provided outside the inner tube, and a combustion exchange section for combustion air and exhaust gas is provided upstream of the flame stabilizing section. A non-ferrous metal molten metal holding device in which a heating element is placed in a molten metal holding furnace. 2. A heating body comprising a flame holding part provided on one side of the inner pipe, an outer pipe provided outside the inner pipe, and a heat exchange part for combustion air exhaust gas provided upstream of the flame holding part,
A non-ferrous metal molten metal holding device, which is charged into a molten metal holding furnace, and has fireproof partition walls on both sides of the heating body, and the partition walls constitute a pouring chamber, a heating chamber, and a pumping chamber.