Tower type nonferrous metal melting furnace

Abstract

To provide a tower type nonferrous metal melting furnace which does not cause carbon dioxide, is excellent in energy efficiency and is inexpensive in facility cost.SOLUTION: A nonferrous metal melting furnace 1 melts a nonferrous metal material M charged into a tower-shaped preheating chamber 10 from an upper opening part 10c, by utilizing heating of air by a heating device 11 provided outside the preheating chamber 10, and the heating device 11 is composed of an electrothermal heater. The melting furnace 1 includes: a circulation passage 12 which is provided outside the preheating chamber 10 so as to communicate an upper part 10a and a lower part 10b of the preheating chamber 10, and circulates air therein; and a circulation fan 13 which is provided on the circulation passage 12, and circulates the air in the circulation passage 12 by a route from the lower part 10b of the preheating chamber 10 to the upper part 10a thereof inside the preheating chamber 10, and by a route from the upper part 10a of the preheating chamber 10 to the lower part 10b thereof in the outside the preheating chamber 10, while also taking in outside air. In addition, the heating device 11 is provided on the circulation passage 12.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a tower-type non-ferrous metal melting furnace having a tower-shaped preheating chamber. [Background technology]

[0002] Conventionally, a tower-type non-ferrous metal melting furnace as shown in Fig. 4 has been used as equipment for melting non-ferrous metal materials such as aluminum (see, for example, Patent Document 1). This tower-type non-ferrous metal melting furnace burns fossil fuels such as petroleum or natural gas with burner B, and melts non-ferrous metal material M with the heat.

[0003] Among these non-ferrous metal melting furnaces, there is one shown in Figure 5 that burns natural gas (city gas). In this non-ferrous metal melting furnace 30, non-ferrous metal material M is charged into a tower-shaped preheating chamber 31 from an input opening 31a at the top of the chamber, natural gas supplied continuously through a long gas line 32 leading to a gas source is mixed with air supplied from a combustion blower 35, and combusted by a combustion burner 33 equipped with a pilot burner 34, and the non-ferrous metal material M is heated and melted by the flame and high-temperature combustion gas. Although the non-ferrous metal melting furnace 30 that burns natural gas generates less carbon dioxide than one that burns fossil fuels such as petroleum (as shown in FIG. 4), the problem of carbon dioxide generation still remains due to the mechanism of burning fuel. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2001-272171 A Summary of the Invention [Problem to be solved by the invention]

[0005] Today, from the perspective of eliminating carbon dioxide, research and development is being actively conducted in the field of tower-type non-ferrous metal melting furnaces to switch to technologies that do not use fossil fuels or natural gas, and therefore the emergence of tower-type non-ferrous metal melting furnaces that avoid the use of fossil fuels and natural gas is desirable.

[0006] Furthermore, conventional tower-type non-ferrous metal melting furnaces melt materials using only the heat obtained by burning a continuously supplied amount of natural gas, so there is room for improvement in terms of energy efficiency.

[0007] Furthermore, the structure is large and complicated, requiring a long gas line leading to the gas source and a pilot burner to be attached to the combustion burner, and the equipment costs, including maintenance, are high.

[0008] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a tower type non-ferrous metal melting furnace which does not generate carbon dioxide, has excellent energy efficiency, and requires low equipment costs. [Means for solving the problem]

[0009] In order to achieve the above object, the tower-type non-ferrous metal melting furnace (1) of the present invention is a melting furnace in which non-ferrous metal material (M) is fed into a tower-shaped preheating chamber (10) from an upper opening (10c) by heating air (G) using a heating device (11) provided outside the preheating chamber (10), and is characterized in that the heating device (11) is an electric heater.

[0010] The tower type non-ferrous metal melting furnace (1) of the present invention further comprises a circulation passage (12) for circulating the air (G), the circulation passage (12) being provided outside the preheating chamber (10) so as to communicate the upper portion (10a) and the lower portion (10b) of the preheating chamber (10); a circulation fan (13) is provided in the circulation passage (12), circulating the air (G) through the circulation passage (12) along a route from the lower part (10b) to the upper part (10a) of the preheating chamber (10) inside the preheating chamber (10) and along a route from the upper part (10a) to the lower part (10b) of the preheating chamber (10) outside the preheating chamber (10), and taking in outside air; The heating device (11) is provided in the circulation passage (12).

[0011] In the present invention, a dust collecting section (14) for collecting dust is provided between the upper portion (10a) of the preheating chamber (10) and the circulation passage (12).

[0012] Here, the symbols in parentheses indicate corresponding elements or items in the drawings and in the detailed description to be described later. Effect of the Invention

[0013] According to the tower-type non-ferrous metal melting furnace of the present invention, non-ferrous metal materials are fed into a tower-shaped preheating chamber from an upper opening, and are melted by heating the air with a heating device installed outside the preheating chamber.Since the heating device is an electric heater, no carbon dioxide is generated, unlike conventional melting furnaces that burn fossil fuels or natural gas.

[0014] That is, in the tower-type non-ferrous metal melting furnace of the present invention, non-ferrous metal materials are melted with heated air, so no carbon dioxide is generated during the melting process. Also, since the air is heated by a heating device composed of an electric heater, no carbon dioxide is generated during the heating process. Therefore, non-ferrous metal materials can be melted without generating carbon dioxide.

[0015] In addition, according to the present invention, a circulation passage is provided that connects the upper and lower parts of the preheating chamber, and a heating device is provided in the circulation passage, so that air heated by the heating device can be repeatedly sent to the preheating chamber. This prevents the heated air from being wasted and results in excellent energy efficiency.

[0016] In addition, because the circulation passage is provided in the order that reaches from the bottom to the top of the preheating chamber, the air used to melt the non-ferrous metal materials in the bottom of the preheating chamber can also be used to heat (preheat) the non-ferrous metal materials that are to be melted after being introduced into the top of the preheating chamber. This allows the non-ferrous metal materials to be melted efficiently with little energy.

[0017] Furthermore, since the heating device for melting non-ferrous metal materials is composed of an electric heater, there is no need to install a long gas line leading to a gas source or a pilot burner attached to a combustion burner, as in the conventional technology. Therefore, the structure is simple, and the equipment costs, including maintenance, are low.

[0018] Furthermore, according to the present invention, a dust collector is provided between the top of the preheating chamber and the circulation passage, so that dust contained in the air discharged from the preheating chamber can be removed by this dust collector. Therefore, clean air can be sent to the circulation passage, the circulation fan, and the heating device, and a decrease in energy efficiency caused by dust can be prevented. In addition, failures of the heating device and the like caused by dust can be prevented, making maintenance easier. [Brief description of the drawings]

[0019] [Figure 1] 1 is a side view showing a configuration of a tower type non-ferrous metal melting furnace according to an embodiment of the present invention. FIG. [Diagram 2] FIG. 2 is an enlarged cross-sectional view showing a portion A in FIG. [Diagram 3] FIG. 2 is an enlarged cross-sectional view showing a portion B in FIG. [Figure 4] FIG. 1 is a cross-sectional view showing a tower-type non-ferrous metal melting furnace according to a conventional example. [Diagram 5] FIG. 11 is a side view showing the configuration of another tower type non-ferrous metal melting furnace according to a conventional example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] A tower type non-ferrous metal melting furnace 1 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG. The tower-type non-ferrous metal melting furnace 1 according to this embodiment has a fundamental configuration that is significantly different from conventional melting furnaces that burn fuels such as fossil fuels and natural gas. That is, this tower-type non-ferrous metal melting furnace 1 heats air G with a heating device 11 composed of an electric heater, and uses the heated air G to melt non-ferrous metal material M such as an aluminum alloy that is fed into a tower-shaped preheating chamber 10, and does not involve a means for burning fuel as in the conventional technology.

[0021] The tower-type non-ferrous metal melting furnace 1 of this embodiment having such a basic configuration includes, in addition to the heating device 11, a circulation passage 12, a circulation fan 13, an air G valve 15, a heated air G supply section 16, multiple temperature sensors 17, and a dust collection section 14.

[0022] The heating device 11 is composed of an electric heater that operates with electricity, and is provided downstream of the circulation passage 12 (between the circulation fan 13 and the heated air supply unit 16). The heating device 11 has a function of heating the air G to a temperature equal to or higher than the melting point of the non-ferrous metal material M to be melted. For example, when the non-ferrous metal material M is an aluminum alloy, its melting point is 660°C, so the heating device 11 heats the air G to a temperature higher than that (for example, close to 1000°C).

[0023] 2 and 3, the circulation passage 12 is composed of a pipe (duct) P made of metal or the like, and is provided outside the preheating chamber 10 in a state in which the upper part 10a and the lower part 10b of the preheating chamber 10 are in communication with each other. Air G circulates inside the circulation passage 12. This pipe P has a heat resistance that allows air G of nearly 1000°C to pass through.

[0024] The circulation fan 13 is provided on the upstream side of the heating device 11 in the circulation passage 12 (between the circulation fan 13 and the heated air supply section 16) and has the ability to send air G along a path from the lower part 10b to the upper part 10a of the preheating chamber 10 inside the preheating chamber 10, and to send air G along a path from the upper part 10a to the lower part 10b of the preheating chamber 10 outside the preheating chamber 10, thereby circulating the air G smoothly and continuously.

[0025] Air valve 15 is provided on the upstream side of circulation fan 13 in circulation passage 12 (between dust collection section 14 and circulation fan 13). Opening and closing this air valve 15 adjusts the amount and temperature of air G flowing through circulation passage 12. That is, opening air valve 15 increases the inflow of air G and lowers the temperature of air G flowing through circulation passage 12, and conversely closing air valve 15 raises the temperature.

[0026] The heated air supply unit 16 is provided in the outer lower part 10b of the preheating chamber 10. The downstream end of the circulation passage 12 is connected to the heated air supply unit 16, and heated air G is supplied to the lower part 10b of the preheating chamber 10 through this heated air supply unit 16. The heated air supply unit 16 is preferably provided with an injection mechanism (such as a nozzle) so that high-pressure air G can be supplied to the non-ferrous metal material M in a jet state.

[0027] The multiple temperature sensors (thermocouples) 17 can be provided at least upstream of the air valve 15 in the circulation passage 12 (between the air valve 15 and the dust collector 14), between the heater 11 and the heated air supply unit 16, and in the heated air supply unit 16. The multiple temperature sensors 17 measure the temperature at each location and send the signals to a control device (not shown). Based on this, the control device sends command signals to the heater 11 and the air valve 15 to control the heating temperature and the amount of air G flowing in, thereby adjusting the temperature of the air G.

[0028] The dust collector 14 is provided between the upper portion 10a of the preheating chamber 10 and the upstream end of the circulation passage 12. The dust collector 14 removes dust discharged together with the air G from the upper portion 10a of the preheating chamber 10. As a result, only clean air G is sent to the heating device 11 and the circulation fan 13.

[0029] The tower type non-ferrous metal melting furnace 1 according to this embodiment operates as follows. First, the heating device 11 is operated by electricity, and the circulation fan 13 is also operated by electricity. As a result, high-temperature air G heated by the heating device 11 is supplied to the lower part 10b of the preheating chamber 10 via the heated air supply unit 16. The high-temperature air G supplied to the lower part 10b of the preheating chamber 10 melts the non-ferrous metal material M present in the lower part 10b of the preheating chamber 10. The melted non-ferrous metal material M becomes fluid and flows into the holding chamber 20 due to its own weight, where the molten state is maintained.

[0030] The high-temperature air G supplied to the preheating chamber 10 heats (preheats) the non-ferrous metal material M in a lump state that has been introduced from the upper opening 10c in the upper part 10a of the preheating chamber 10 by the action of the circulation fan 13. The high-temperature air G that has melted the non-ferrous metal material M in the lower part 10b of the preheating chamber 10 has a temperature that is sufficient to heat the non-ferrous metal material M introduced in the upper part 10a of the preheating chamber 10, although the temperature of the high-temperature air G drops due to the melting (heat exchange). The non-ferrous metal material M heated in the upper portion 10a of the preheating chamber 10 is brought to a high temperature state, and is melted in the lower portion 10b of the preheating chamber 10 in a short period of time.

[0031] The air G sent to the upper part 10a of the preheating chamber 10 heats the nonferrous metal material M by the action of the circulation fan 13, and then passes from the upper part 10a through the dust collector 14 into the circulation passage 12, and is sent again to the heating device 11 where it is heated and becomes high-temperature air G. The air G is then supplied again to the lower part 10b of the preheating chamber 10 via the heated air supply part 16. By circulating the air G in this way, the nonferrous metal material M is continuously heated and melted.

[0032] An opening / closing lid 18 is provided at the upper opening 10c of the preheating chamber 10, and by closing this opening / closing lid 18, the air G sent to the upper part 10a of the preheating chamber 10 can be prevented from being discharged to the outside.

[0033] In the tower-type non-ferrous metal melting furnace 1 according to this embodiment, non-ferrous metal material M is melted with air G heated to a high temperature, and the air G is heated by a heating device 11 composed of an electric heater, so no carbon dioxide is generated at this heating stage. In addition, since the non-ferrous metal material M is melted with the heated high-temperature air G, no carbon dioxide is generated at this melting stage either. Therefore, the non-ferrous metal material M can be melted without generating carbon dioxide.

[0034] In addition, the tower-type non-ferrous metal melting furnace 1 according to this embodiment is provided with a heating device 11 in the circulation passage 12, and the air G heated by the heating device 11 is continuously sent to the preheating chamber 10 while being circulated. Therefore, unlike, for example, heating and sending fresh air G having the outside air temperature, this has extremely excellent energy efficiency.

[0035] In addition, since the circulation passage 12 is provided in a route such that the air G reaches the upper part 10a from the lower part 10b of the preheating chamber 10, the air G used to melt the non-ferrous metal material M in the lower part 10b of the preheating chamber 10 can be used to heat the non-ferrous metal material M in a lump state that is not melted in the upper part 10a of the preheating chamber 10. This use of the air G can also improve energy efficiency.

[0036] Furthermore, since the heating device 11 is an electric heater, there is no need for a configuration like that of a conventional non-ferrous metal melting furnace, which requires a combustion burner, pilot burner, etc. Therefore, the structure is simple, and the equipment costs, including maintenance, can be kept low.

[0037] Furthermore, since a dust collecting section 14 for collecting dust is provided between the upper portion 10a of the preheating chamber 10 and the circulation passage 12, the dust contained in the air G discharged from the preheating chamber 10 can be removed by this dust collecting section 14. Therefore, only clean air G can be sent to the circulation passage 12, the circulation fan 13, and the heating device 11, and a decrease in energy efficiency caused by the influence of dust can be prevented. Furthermore, breakdowns of the heating device 11, the circulation fan 13, etc. caused by dust can be prevented, making maintenance easier.

[0038] Furthermore, the non-ferrous metal melting furnace 1, which heats air G with a heating device 11 consisting of an electric heater and uses this heated high-temperature air G to melt non-ferrous metal material M, is not described at all in the above-mentioned patent documents. [Explanation of symbols]

[0039] 1 Tower type non-ferrous metal melting furnace 10 Preheating chamber 10a Upper 10b Lower 10c Upper opening 11 Heating device 12 Circulation passage 13 Circulation fan 14 Dust collection section 15 Air valve 16 Heated air supply section 17 Temperature Sensor 18 Opening and closing lid 20 Holding chamber 30 Non-ferrous metal melting furnace 31 Preheating Room 31a Input opening 32 Gas Line 33 Combustion burner 34 Pilot Burner 35 Combustion Blower B Burner G Air M Non-ferrous metal materials P Pipe

Claims

1. A tower-type non-ferrous metal melting furnace in which non-ferrous metal materials are fed into a tower-shaped preheating chamber from an upper opening, and the non-ferrous metal materials are melted by heating air with a heating device provided outside the preheating chamber, 4. A tower-type non-ferrous metal melting furnace, wherein the heating device is an electric heater.

2. a circulation passage provided outside the preheating chamber so as to communicate an upper portion with a lower portion of the preheating chamber, the circulation passage allowing the air to circulate; 2. The tower type non-ferrous metal melting furnace according to claim 1, further comprising a circulation fan that is provided in the circulation passage and that circulates the air through the circulation passage in a sequence from the lower part to the upper part of the preheating chamber inside the preheating chamber and in a sequence from the upper part to the lower part of the preheating chamber outside the preheating chamber, and that takes in outside air, and the heating device is provided in the circulation passage.

3. 3. The tower type non-ferrous metal melting furnace according to claim 2, further comprising a dust collecting section for collecting dust provided between an upper portion of said preheating chamber and said circulation passage.

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