Smelting furnace used in inert gas environment

Abstract

The invention relates to the technical field of smelting furnaces, and discloses a smelting furnace used in an inert gas environment, comprising: a furnace body used for accommodating an object to be smelted; a cavity is formed between the sealing assembly and the furnace body, and the interior of the cavity is divided into a first area and a second area; the air extracting and supplying mechanism comprises an air extracting part for extracting air in the cavity and an air supplying part for injecting air into the cavity; the airflow driving mechanism is provided with a high-pressure end communicated with the first area and a low-pressure end communicated with the second area; according to the smelting furnace used in the inert gas environment, the sealed cavity is formed by the sealing assembly, the graphite crucible is isolated from the external environment, the air exhaust and supply mechanism is vacuumized firstly and then filled with inert gas, and the air pressure sensor and the oxygen concentration sensor are matched for real-time monitoring, so that the problem of molten aluminum oxidation of a traditional open furnace is solved, and generation of Al2O3 inclusions is reduced.

Description

Technical Field

[0001] This invention relates to the field of smelting furnace technology, specifically to a smelting furnace for use in an inert gas environment. Background Technology

[0002] In industrial production, aluminum alloy smelting is carried out using medium-frequency induction furnaces and graphite crucibles. The medium-frequency induction furnace generates eddy currents inside the metal through the principle of electromagnetic induction, achieving rapid and uniform heating. The graphite crucible, as a smelting container, directly holds aluminum ingots or recycled materials.

[0003] Patent CN217005320U discloses a low-energy-consumption medium-frequency induction furnace. This furnace includes a shell, a discharge assembly, a retraction assembly, and a waste heat recovery assembly. An inner liner is located inside the shell, and a discharge pipe is fixedly installed at the bottom of the inner liner. The bottom end of the discharge pipe penetrates the bottom of the shell and extends to the lower part of the shell. An elliptical shell is fixedly installed on the discharge pipe, and an electromagnetic coil is fitted onto the outer wall of the electromagnetic coil. This low-energy-consumption medium-frequency induction furnace facilitates the transport of molten metal from the inner liner to the outside of the shell through the discharge pipe and the elliptical shell, avoiding the need for tilting the furnace. During the metal feeding process, direct contact between the inside of the shell and the external environment is avoided, reducing heat loss and power consumption. Furthermore, waste heat can be recovered from the furnace, further improving energy utilization.

[0004] However, the aforementioned medium-frequency induction furnace still has the following problems in actual use: During the process of heating and melting metallic aluminum using a medium-frequency induction furnace, aluminum, being a chemically reactive metal, readily reacts with oxygen in the air at high temperatures (typically 700–800℃) to form aluminum oxide. This oxide product has a high melting point (approximately 2050℃), is dense, and is difficult to melt. It easily exists in the melt as inclusions, which not only affects the purity of the molten aluminum but may also adversely affect subsequent casting processes and the performance of the castings.

[0005] Currently, most industrially used medium-frequency induction furnaces have an open or semi-open structure, with the graphite crucible placed inside the induction coil and its top opening directly exposed to the atmosphere. Although conventional operations involve sprinkling chloride / fluoride salts onto the surface of the molten aluminum to form a liquid protective film, which isolates it from the air to some extent, this method is still insufficient to completely prevent the molten aluminum from contacting the surrounding atmosphere. Therefore, oxidation reactions inevitably occur during the smelting process, leading to metal loss, which not only reduces the aluminum yield but also increases production costs and the burden of waste disposal. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a smelting furnace for use in an inert gas environment, which can reduce the probability of oxidation of metallic aluminum during the smelting process.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a smelting furnace for use in an inert gas environment, comprising: A furnace body, used to hold objects to be melted; A sealing assembly forms a cavity between itself and the furnace body, and the cavity is divided into a first region and a second region. An air extraction and supply mechanism includes an air extraction component for extracting air from the cavity and an air supply component for injecting gas into the cavity. An airflow drive mechanism having a high-pressure end communicating with a first region and a low-pressure end communicating with a second region; The heat exchange mechanism has a cooling zone for cooling the gas inside the high-pressure end and a preheating zone for preheating the gas at the low-pressure end. The heat exchange mechanism can automatically switch the airflow path according to the pressure. The filtration mechanism is used to filter impurities in the airflow path after cooling.

[0008] Furthermore, the furnace body includes an outer shell, an extension plate, and a graphite crucible with an opening for melting materials. The graphite crucible is located inside the outer shell, and an electromagnetic coil is provided between the graphite crucible and the outer shell. The extension plate is fixedly connected to one side of the upper end of the outer shell, and the extension plate is connected to both the high-pressure end and the low-pressure end of the heat exchange mechanism. The outer shell is connected to the sealing assembly through a rotating component.

[0009] Furthermore, the sealing assembly includes a sealing cover rotatably connected to the housing via a rotating component and a partition fixedly connected inside the sealing cover. The first and second regions of the cavity are located on both sides of the partition, and the cavity is located between the sealing cover, the housing, and the extension plate. A sealing groove is provided on the side of the sealing cover near the housing. A sealing ring is fixedly connected to the upper surfaces of the housing and the extension plate, and the sealing ring cooperates with the sealing groove to seal.

[0010] Furthermore, the suction end of the suction and supply mechanism is a vacuum tube, and the supply end of the suction and supply mechanism is a gas filling tube. Both the vacuum tube and the gas filling tube are fixedly connected to the sealing cover, and both the vacuum tube and the gas filling tube are connected to the cavity.

[0011] Furthermore, the sealed cover is equipped with a monitoring mechanism inside to monitor the internal pressure and oxygen content of the cavity in real time. The monitoring mechanism includes a pressure sensor for monitoring the internal pressure of the cavity and an oxygen concentration sensor for monitoring the internal oxygen content of the cavity.

[0012] Furthermore, the heat exchange mechanism includes: Cooling components are used to cool the airflow from the first area toward the filtration mechanism; A preheating component is used to preheat the airflow from the filtration unit to the second zone; A circulating pump is used to drive the flow of the internal medium between the cooling and preheating components; A diversion pipe is used to divert the airflow from the first area to the filtration unit; Differential pressure control valves are used to automatically change the airflow path inside the manifold based on pressure.

[0013] Furthermore, the cooling assembly includes a cooling tank, a first water pipe, a second water pipe, a main air pipe, an auxiliary air pipe, a first air outlet pipe, a second air outlet pipe, and a manifold. The cooling tank has a cold water chamber inside. The first air outlet pipe, the second air outlet pipe, and the manifold are all located within the cold water chamber. One end of the cooling tank is fixedly connected to both the main air pipe and the auxiliary air pipe. The ends of the main air pipe and the auxiliary air pipe furthest from the cooling tank are respectively fixedly connected to a distributor pipe and a differential pressure control valve. The same end of both the first and second water pipes is fixedly connected to the cooling tank. The first water outlet pipe... The other end is fixedly connected to the circulating pump, the other end of the second water pipe is connected to the preheating component, one end of the first air pipe and the second air pipe are both fixedly connected to the cold water chamber of the cooling tank, the other end of the first air pipe and the second air pipe are both fixedly connected to one end of the collecting pipe, the other end of the collecting pipe is fixedly connected to one end of the filter mechanism, the split pipe, the main air pipe, the first air pipe, the collecting pipe and the airflow drive mechanism are internally connected, the split pipe, the differential pressure control valve, the auxiliary air pipe, the second air pipe, the collecting pipe and the filter mechanism are internally connected.

[0014] Furthermore, the preheating assembly includes a third air outlet pipe, a third water outlet pipe, a fourth water outlet pipe, a fourth air outlet pipe, a preheating tank, and a fifth air outlet pipe. The preheating tank has a preheating chamber inside. The fourth air outlet pipe is located within the preheating chamber. One end of the third air outlet pipe is connected to a filter mechanism, and the other end of the third air outlet pipe is fixedly connected to one end of the preheating tank. The other end of the preheating tank is fixedly connected to one end of the fifth air outlet pipe, and the other end of the fifth air outlet pipe is connected to an extension plate. Both ends of the fourth air outlet pipe are fixedly connected to both ends of the preheating chamber. The filter mechanism... The third, fourth, and fifth air outlet pipes are connected to the interior of the cavity. The same end of the third and fourth water outlet pipes is fixedly connected to the outer wall of the preheating tank. The other end of the third water outlet pipe is fixedly connected to the end of the circulating pump away from the first water outlet pipe. The other end of the fourth water outlet pipe is fixedly connected to the end of the second water outlet pipe away from the cooling tank. A one-way valve restricting the direction of water flow is installed inside the fourth water outlet pipe. The cooling chamber, the first water outlet pipe, the circulating pump, the third water outlet pipe, the preheating chamber, the fourth water outlet pipe, and the second water outlet pipe are internally connected.

[0015] Furthermore, a first connecting pipe and a second connecting pipe are fixedly connected to the side of the extension plate away from the sealing cover. The first connecting pipe and the second connecting pipe are located on both sides of the partition plate. The end of the diversion pipe away from the main gas pipe and the differential pressure control valve is fixedly connected to the first connecting pipe. The end of the fifth gas pipe away from the preheating tank is fixedly connected to the second connecting pipe.

[0016] Furthermore, the filtration mechanism includes a first filter element and a second filter element. The two ends of the first filter element are fixedly connected to the end of the collecting pipe away from the first air outlet pipe and the air inlet end of the airflow drive mechanism, respectively. The two ends of the second filter element are fixedly connected to the air outlet end of the airflow drive mechanism and the end of the third air outlet pipe away from the preheating tank, respectively.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. This type of smelting furnace used in an inert gas environment has a sealing component that forms a closed cavity to isolate the graphite crucible from the external environment. The gas extraction and supply mechanism first evacuates the vacuum and then fills it with inert gas. With the help of a pressure sensor and an oxygen concentration sensor for real-time monitoring, it solves the problem of aluminum liquid oxidation in traditional open furnaces and reduces the formation of Al2O3 inclusions. 2. This type of smelting furnace used in an inert gas environment forms a closed loop of "cavity → cooling component → filtration component → preheating component → cavity" through an airflow drive mechanism. The differential pressure control valve of the heat exchange mechanism automatically switches the airflow path (when the main gas pipe is blocked, the airflow is diverted through the auxiliary gas pipe). The circulating airflow maintains a slight positive pressure to counteract air infiltration caused by seal leakage and reduce inert gas consumption. At the same time, the differential pressure control valve prevents the circulation from being interrupted due to filter blockage. 3. This type of smelting furnace is used in an inert gas environment. The cooling component cools down the high-temperature circulating gas, protecting the downstream equipment (filtration mechanism, airflow drive mechanism) from high-temperature damage. The preheating component uses the residual heat of the cooling medium to preheat the low-temperature circulating gas. The preheated gas enters the cavity to avoid cold gas impacting the aluminum liquid and causing temperature fluctuations. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall appearance of the present invention; Figure 2 This is a schematic diagram of the overall appearance of the invention from another perspective; Figure 3 This is a schematic diagram of the overall appearance of the sealing cap of the present invention after it has been unfolded. Figure 4 This is a bottom-view perspective view of the various components of the furnace body of the present invention; Figure 5 This is a detailed connection diagram of the airflow drive mechanism, heat exchange mechanism, and two filtration mechanisms of the present invention; Figure 6 This is a detailed connection diagram of the cooling assembly, manifold, and differential pressure control valve of the present invention; Figure 7 This is a detailed connection diagram of the various components of the preheating assembly of the present invention.

[0019] In the diagram: 100, furnace body; 110, outer shell; 120, sealing ring; 130, extension plate; 131, first connecting pipe; 132, second connecting pipe; 140, graphite crucible; 200. Sealing assembly; 210. Sealing cap; 211. Sealing groove; 220. Partition plate; 300. Vacuum supply mechanism; 310. Vacuum tube; 320. Gas supply tube; 400. Monitoring agency; 410. Barometric pressure sensor; 420. Oxygen concentration sensor; 500. Filtration mechanism; 600. Airflow drive mechanism; 700. Heat exchange mechanism; 710. Cooling assembly; 711. Cooling tank; 712. First water pipe; 713. Second water pipe; 714. Main air pipe; 715. Auxiliary air pipe; 716. First air pipe; 717. Second air pipe; 718. Manifold; 720. Circulating pump; 730. Preheating component; 731. Third air supply pipe; 732. Third water supply pipe; 733. Fourth water supply pipe; 734. Fourth air supply pipe; 735. Preheating tank; 736. Fifth air supply pipe 740, Diverter pipe; 750, Differential pressure control valve. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0021] Please see Figures 1-7 A smelting furnace for use in an inert gas environment, including: Furnace body 100, used to hold the objects to be melted; The sealing assembly 200 forms a cavity with the furnace body 100, and the cavity is divided into a first region and a second region. The air extraction and supply mechanism 300 includes an air extraction component for extracting air from the cavity and an air supply component for injecting gas into the cavity. The airflow drive mechanism 600 has a high-pressure end communicating with a first region and a low-pressure end communicating with a second region. The heat exchange mechanism 700 has a cooling zone for cooling the gas inside the high-pressure end and a preheating zone for preheating the gas at the low-pressure end. The heat exchange mechanism 700 can automatically switch the airflow path according to the pressure. The 500 filter unit is used to filter impurities in the airflow path after cooling.

[0022] More specifically, the main function of the airflow drive mechanism 600 is to carry the high-temperature gas inside the cavity through the cavity's first region - the cooling zone of the heat exchange mechanism 700 - the filter mechanism 500 - the airflow drive mechanism 600 - the filter mechanism 500 - the preheating zone of the heat exchange mechanism 700 - the cavity's second region to achieve circulation. (In addition, because the heat exchange mechanism 700 can automatically switch the airflow path according to the pressure, if the pressure in the main pipeline increases due to blockage or other reasons in the cooling zone of the heat exchange mechanism 700, the high-temperature gas can automatically switch to the auxiliary path and continue to circulate through the preheating zone of the heat exchange mechanism 700 and subsequent steps of the preheating zone of the heat exchange mechanism 700.) Therefore, the specific model of the airflow drive mechanism 600 can be a centrifugal fan, an axial fan, or an air pump, etc., which is not limited here.

[0023] like Figures 1-3 As shown, the furnace body 100 includes an outer shell 110, an extension plate 130, and a graphite crucible 140 with an opening for melting materials. The graphite crucible 140 is located inside the outer shell 110, and an electromagnetic coil is provided between the graphite crucible 140 and the outer shell 110. The extension plate 130 is fixedly connected to one side of the upper end of the outer shell 110, and the extension plate 130 is connected to both the high-pressure end and the low-pressure end of the heat exchange mechanism 700. The outer shell 110 is connected to the sealing assembly 200 through a rotating component.

[0024] More specifically, by providing the outer casing 110, the graphite crucible 140 inside the outer casing 110 and the electromagnetic coil located between the outer casing 110 and the graphite crucible 140 can be protected, reducing the probability of the graphite crucible 140 and the electromagnetic coil being damaged by impact. By setting the extension plate 130, the area (or length) of the upper surface of the outer shell 110 can be increased, which can provide a connection point for the heat exchange mechanism 700, while the filter mechanism 500 and other components will not affect the normal operation of the graphite crucible 140 and the electromagnetic coil. The graphite crucible 140 is a key piece of equipment in the furnace body 100, with metallic aluminum located inside. To ensure the service life of the graphite crucible 140, a boron nitride coating can be applied to the surface of the graphite crucible 140 (and the subsequent aluminum molten ladle). The main component is hexagonal boron nitride, with a coverage area of ​​25-30 m2 / L, viscosity of 4000-5000 CPS, solid content of 25%-30%, specific gravity of 1.2 (g / cm3), and color and appearance of white milky substance. Low-temperature baking: Place the graphite crucible 140 in a cooled furnace or room temperature furnace, heat it to 100-150°C, keep it at that temperature for 1-2 hours, and completely remove moisture; Medium temperature rise: Continue to slowly rise to 300-400°C and hold for 1 hour. The heating rate during this stage is ≤100°C / hour. Rise to working temperature: Finally, slowly raise the temperature to 750-800°C (the common working temperature for aluminum alloys) and maintain it for more than 30 minutes to ensure that the crucible is heated evenly.

[0025] like Figures 1-3 As shown, the sealing assembly 200 includes a sealing cover 210 rotatably connected to the outer shell 110 via a rotating member and a partition 220 fixedly connected inside the sealing cover 210. The first region and the second region of the cavity are located on both sides of the partition 220, and the cavity is located between the sealing cover 210, the outer shell 110 and the extension plate 130. A sealing groove 211 is provided on the side of the sealing cover 210 near the outer shell 110. A sealing ring 120 is fixedly connected to the upper surfaces of the outer shell 110 and the extension plate 130. The sealing ring 120 cooperates with the sealing groove 211 to seal.

[0026] More specifically, by setting the sealing cover 210, which has an indented space on the side facing the outer shell 110, the sealing cover 210, together with the outer shell 110 and the extension plate 130, can form the aforementioned "cavity", thereby isolating the metallic aluminum inside the graphite crucible 140 from the external environment, thereby reducing the probability of oxidation when the metallic aluminum melts. In addition, by setting the sealing groove 211 and the sealing ring 120, the sealing performance between the sealing cover 210 and the outer shell 110 and the extension plate 130 can be further improved when the sealing cover 210 is placed on the outer shell 110 and the extension plate 130, thus improving the effective conditions for vacuuming and subsequent injection of inert gas. It should be noted here that: Figure 2 As shown, the outer casing 110 and the sealing cover 210 can rotate via a rotating block and a rotating rod. Alternatively, other components with equivalent functions can be used (the effect is as follows). Figure 3 As shown in the figure, the specific details are not limited; in addition, the outer shell 110 and the sealing cover 210 can also be locked together by a mounting plate and bolts (or other locking structures) to further improve the sealing effect.

[0027] like Figure 1 and Figure 3 As shown, the vacuuming end of the vacuuming and supplying mechanism 300 is a vacuum tube 310, and the supplying end of the vacuuming and supplying mechanism 300 is a gas supply tube 320. Both the vacuum tube 310 and the gas supply tube 320 are fixedly connected to the sealing cover 210, and both the vacuum tube 310 and the gas supply tube 320 are connected to the cavity.

[0028] More specifically, by setting up a vacuum tube 310, after solid aluminum is added into the graphite crucible 140, the sealing cap 210 is sealed through the sealing groove 211 and the sealing ring 120. At this time, in order to prevent the solid aluminum from reacting with the oxygen inside the cavity, a vacuum pump can be connected to the vacuum tube 310 to remove the gas inside the cavity first, thereby directly reducing or isolating the oxygen. By setting up the gas supply pipe 320, after the external vacuum pump removes the gas inside the cavity, oxygen may still enter the cavity from the sealing groove 211 and sealing ring 120 (or other locations). At this time, connect the gas supply pipe 320 to an external gas pump to supply inert gas (such as nitrogen or argon). As the inert gas content inside the cavity increases, the probability of external oxygen entering can be effectively reduced.

[0029] like Figure 1 and Figure 3 As shown, the sealing cover 210 is equipped with a monitoring mechanism 400 for real-time monitoring of the internal pressure and oxygen content of the cavity. The monitoring mechanism 400 includes a pressure sensor 410 for monitoring the internal pressure of the cavity and an oxygen concentration sensor 420 for monitoring the internal oxygen content of the cavity.

[0030] More specifically, by setting up a pressure sensor 410, the micro-positive pressure environment inside the furnace (such as 0.1-0.2 kPa) can be monitored in real time to prevent air from seeping in (if the pressure is <0.1 kPa, the external inert gas supply pump will be automatically started). By setting up an oxygen concentration sensor 420, the oxygen concentration in the furnace can be monitored in real time to ensure that it is ≤0.1% (O2≈5% in traditional furnaces), thus preventing the aluminum liquid from oxidizing and generating Al2O3 inclusions. In addition, it should be noted that the pressure sensor 410 and the oxygen concentration sensor 420 are both installed on the top of the sealing cover 210 and do not come into contact with the molten aluminum. The pressure sensor 410 is encapsulated with a high-temperature alloy (such as 316L stainless steel) or ceramic diaphragm, and has an operating temperature range of 200-800℃ (meeting the requirements of aluminum smelting). Its basic principle is to measure pressure through strain gauges or capacitance, without contact with high-temperature media. The oxygen concentration sensor 420 uses ceramic encapsulation and operates in a temperature range of 600-1000℃ (fully covering the 700-850℃ range of aluminum smelting). Its basic principle is to detect oxygen concentration by utilizing the oxygen ion conductivity of zirconium oxide. It is important to note that even with the sealing groove 211 and the sealing ring 120, an absolute seal between the sealing cover 210 and the outer shell 110 cannot be achieved (e.g., due to aging of the seals or thermal expansion of the furnace body causing gaps). If circulation is not controlled, the pressure inside the furnace will drop (air infiltration), causing the oxygen concentration to rise again (from <0.1% to over 1%), and the oxidation of the molten aluminum will intensify (increase in Al2O3 inclusions). By setting up the airflow drive mechanism 800, the gas inside the furnace is extracted from the bottom, purified, and sent back to the cavity, forming a closed loop to maintain a slight positive pressure (0.1-0.2 kPa) and counteract the air infiltration caused by leakage. In addition, during the smelting process, inert gases (such as argon and nitrogen) are consumed (e.g., inert gas molecules are adsorbed on the surface of the molten aluminum and in the pores of the furnace lining). Therefore, at this time, the gas loss in the circulation (such as leakage) is monitored by the pressure sensor 410 and the oxygen concentration sensor 420. Of course, a gas flow meter can also be added to achieve automatic replenishment of a small amount of inert gas by the external gas pump (only 10%-20% of the initial injection amount) to maintain a low-oxygen environment.

[0031] like Figure 1 , Figure 2 , Figures 5-7 As shown, the heat exchange mechanism 700 includes: Cooling assembly 710 is used to cool the airflow from the first region to the filter unit 500; Preheating component 730 is used to preheat the airflow from the filter unit 500 to the second zone; A circulating pump 720 is used to drive the flow of the internal medium between the cooling assembly 710 and the preheating assembly 730. The diversion pipe 740 is used to divert the airflow from the first region to the filter unit 500; Differential pressure control valve 750 is used to automatically change the airflow path inside the diverter 740 according to the pressure.

[0032] More specifically, by setting up a circulating pump 720, the power to circulate the heat exchange medium within the cooling assembly 710 and the preheating assembly 730 can be provided; By setting up the diversion pipe 740, when the main pipe inside the cooling assembly 710 is blocked and the differential pressure control valve 750 is automatically opened, the gas flowing from the first area of ​​the cavity can be guided to the differential pressure control valve 750 and flow from the differential pressure control valve 750. By setting a differential pressure control valve 750, under normal conditions (e.g., no blockage) of the main pipe inside the cooling assembly 710, the internal valve disc of the differential pressure control valve 750 closes the bypass under the action of spring force, and all the gas flows through the main pipe; while in the main pipe, due to the accumulation of dust / slag, the flow cross-sectional area is reduced, the friction resistance increases, the pressure at the outlet end drops and the differential pressure increases. When it exceeds the set threshold, the differential pressure force overcomes the spring force, the valve disc opens, and the gas is diverted through the bypass (secondary pipe).

[0033] like Figure 6 As shown, the cooling assembly 710 includes a cooling tank 711, a first water pipe 712, a second water pipe 713, a main air pipe 714, an auxiliary air pipe 715, a first air outlet pipe 716, a second air outlet pipe 717, and a manifold 718. The cooling tank 711 has a cold water chamber inside. The first air outlet pipe 716, the second air outlet pipe 717, and the manifold 718 are all located within the cold water chamber. One end of the cooling tank 711 is fixedly connected to both the main air pipe 714 and the auxiliary air pipe 715. The ends of the main air pipe 714 and the auxiliary air pipe 715 furthest from the cooling tank 711 are fixedly connected to a distributor pipe 740 and a differential pressure control valve 750, respectively. The same end of both the first water pipe 712 and the second water pipe 713 is fixedly connected to the cooling tank 711. The other end of 712 is fixedly connected to the circulating pump 720, the other end of the second water pipe 713 is connected to the preheating component 730, one end of the first air pipe 716 and the second air pipe 717 are both fixedly connected to the cold water chamber of the cooling tank 711, the other end of the first air pipe 716 and the second air pipe 717 are both fixedly connected to one end of the collecting pipe 718, the other end of the collecting pipe 718 is fixedly connected to one end of the filter mechanism 500, the branch pipe 740, the main air pipe 714, the first air pipe 716, the collecting pipe 718 and the airflow drive mechanism 600 are internally connected, the branch pipe 740, the differential pressure control valve 750, the auxiliary air pipe 715, the second air pipe 717, the collecting pipe 718 and the filter mechanism 500 are internally connected.

[0034] More specifically, by setting up a cooling tank 711, heat exchange medium can be stored in its internal cold water chamber, which, together with the high-temperature gas passing through the first air outlet 716 and the second air outlet 717, can be cooled. This can prevent high-temperature gas from flushing the filter mechanism 500 for a long time and reducing the life of the filter mechanism 500 (although the filter mechanism 500 is made of high-temperature resistant material, even the most heat-resistant material will have its lifespan reduced if it is exposed to high temperatures for a long time). By setting up the first water pipe 712 and the second water pipe 713, the heat exchange medium inside the cooling chamber can be guided into the preheating component 730 in conjunction with the circulating pump 720. By setting up a main air pipe 714, an auxiliary air pipe 715, a first air outlet pipe 716, and a second air outlet pipe 717, which are respectively connected to a diverter pipe 740 and a differential pressure control valve 750, it is possible to ensure that the second air outlet pipe 717 will not affect the gas flow when the high-temperature gas is flowing normally inside the first air outlet pipe 716. Conversely, if the pressure rises due to blockage inside the first air outlet pipe 716, the differential pressure control valve 750 can be automatically opened to allow the high-temperature gas to flow away from the second air outlet pipe 717. Since both the first air outlet pipe 716 and the second air outlet pipe 717 are located in the cooling chamber, the heat exchange effect is not affected. By setting up the collection pipe 718, the gas flowing from either or both of the first air outlet pipe 716 and the second air outlet pipe 717 can be accurately collected and guided into the filter mechanism 500.

[0035] like Figure 7 As shown, the preheating assembly 730 includes a third air pipe 731, a third water pipe 732, a fourth water pipe 733, a fourth air pipe 734, a preheating tank 735, and a fifth air pipe 736. The preheating tank 735 has a preheating chamber inside, and the fourth air pipe 734 is located within the preheating chamber. One end of the third air pipe 731 is connected to the filter mechanism 500, and the other end of the third air pipe 731 is fixedly connected to one end of the preheating tank 735. The other end of the preheating tank 735 is fixedly connected to one end of the fifth air pipe 736, and the other end of the fifth air pipe 736 is connected to the extension plate 130. Both ends of the fourth air pipe 734 are fixedly connected to both ends of the preheating chamber. The filter mechanism 500... The third air pipe 731, the fourth air pipe 734, and the fifth air pipe 736 are connected to the interior of the cavity. The same end of the third water pipe 732 and the fourth water pipe 733 are fixedly connected to the outer wall of the preheating tank 735. The other end of the third water pipe 732 is fixedly connected to the end of the circulation pump 720 away from the first water pipe 712. The other end of the fourth water pipe 733 is fixedly connected to the end of the second water pipe 713 away from the cooling tank 711. The fourth water pipe 733 is equipped with a one-way valve to restrict the direction of water flow. The cooling cavity, the first water pipe 712, the circulation pump 720, the third water pipe 732, the preheating cavity, the fourth water pipe 733, and the second water pipe 713 are internally connected.

[0036] More specifically, by setting up a preheating tank 735, the preheating medium can be stored in its internal preheating chamber, and the high-temperature medium transported from the cooling chamber can be transferred to the fourth air outlet pipe 734 to preheat the gas that was cooled in the early stage. By setting up the third air outlet pipe 731, the fourth water outlet pipe 733, the fourth air outlet pipe 734 and the fifth air outlet pipe 736, the low-temperature clean gas flowing from inside the filter mechanism 500 can be preheated and heated, preventing cold gas from entering the cavity and affecting the normal smelting of aluminum. By setting up the third water pipe 732 and the fourth water pipe 733, the preheating tank 735 can be connected to the circulating pump 720, while providing a flow path for the heat exchange medium (because the fourth water pipe 733 is equipped with a one-way valve, the heat exchange medium can only flow in the direction of cooling chamber - first water pipe 712 - circulating pump 720 - third water pipe 732 - preheating chamber - fourth water pipe 733 - second water pipe 713 - cooling chamber).

[0037] like Figure 2 and Figure 4 As shown, the first connecting pipe 131 and the second connecting pipe 132 are fixedly connected to the side of the extension plate 130 away from the sealing cover 210. The first connecting pipe 131 and the second connecting pipe 132 are located on both sides of the partition plate 220. The end of the diversion pipe 740 away from the main gas pipe 714 and the differential pressure control valve 750 is fixedly connected to the first connecting pipe 131. The end of the fifth gas pipe 736 away from the preheating tank 735 is fixedly connected to the second connecting pipe 132.

[0038] More specifically, by setting the first connecting pipe 131 and the second connecting pipe 132, a connection point can be provided between the extension plate 130 and the heat exchange mechanism 700, ensuring that the spare gas of the heat exchange mechanism 700 can be accurately and effectively circulated. By setting the partition 220, the end of the sealing cover 210 near the extension plate 130 can be separated, so that the gas entering the first connecting pipe 131 can be slightly separated from the gas coming out of the second connecting pipe 132, thereby improving the gas circulation effect inside the cavity.

[0039] like Figure 1 and Figure 2 As shown, the filtration mechanism 500 includes a first filter element and a second filter element. The two ends of the first filter element are fixedly connected to the end of the collecting pipe 718 away from the first air outlet pipe 716 and the air inlet end of the airflow drive mechanism 600, respectively. The two ends of the second filter element are fixedly connected to the air outlet end of the airflow drive mechanism 600 and the end of the third air outlet pipe 731 away from the preheating tank 735, respectively.

[0040] More specifically, the filter mechanism 500 is divided into an "upstream" part and a "downstream" part. The two parts are respectively installed at the air inlet end and the air outlet end of the airflow drive mechanism 600, and different filter materials can be filled inside the two parts respectively.

[0041] It is important to note that because the particle size of impurities in the circulating gas of aluminum smelting varies greatly (from large slag fragments >100μm to fine Al2O3 dust and fluorides <10μm), if filter materials with the same structure are used, such as small-particle filter materials (e.g., porous ceramics), large-particle impurities will clog the ceramic pores (leading to a sharp drop in filtration efficiency and a dramatic increase in wind resistance), requiring frequent replacement of the ceramics; while if large-particle filter materials (e.g., sintered metal mesh) are used, fine-particle impurities will penetrate the mesh (and cannot be removed, leading to an increase in Al2O3 inclusions in the furnace). Therefore, in practical applications, the filter mechanism 500 is located in the "upstream" part of the air inlet end of the airflow drive mechanism 600, and its interior can be equipped with filter materials (such as metal sintered mesh) that can intercept larger particles. The filter mechanism 500 is located in the "downstream" part of the air outlet end of the airflow drive mechanism 600, and its interior can be equipped with filter materials (such as porous ceramics) that can intercept smaller particles. Specifically, the airflow drive mechanism 600 is the core power equipment of the system. Large particulate impurities (>10μm) will cause severe wear to it. The filtration accuracy of the sintered metal mesh (1-50μm) can effectively intercept these large particles and prevent them from entering the airflow drive mechanism 600. In addition, large particulate impurities will increase the viscosity and density of the gas, resulting in an increase in the workload of the airflow drive mechanism 600. After the sintered metal mesh intercepts the large particles, the flow resistance of the gas is reduced, and the airflow drive mechanism 600 can maintain operation at the optimal operating point. Molten aluminum is highly chemically reactive (metal activity series: Al > Fe). Fine particulate impurities (such as Al2O3 dust <10μm and fluorides) react with molten aluminum to form an Al2O3 oxide film (melting point 2050℃), leading to accelerated oxidation of the molten aluminum. The high-precision filtration (0.1-10μm) of porous ceramics can effectively remove these fine particles (filtration efficiency >99%), preventing them from contacting the molten aluminum. Furthermore, the purity of inert gases (such as argon) directly affects the quality of aluminum smelting (such as the purity of aluminum and the mechanical properties of castings). The high filtration precision of porous ceramics can remove "active impurities" (such as O2 and H2O) from the gas, ensuring the purity of the inert gas. Finally, it should be noted that the "upstream" and "downstream" parts of the filter mechanism 500 are connected by flanges. Therefore, during regular maintenance, the flanges can be separated to inspect and replace the filter material inside the two parts. This is existing technology and will not be described in detail here.

[0042] like Figures 1 to 7 As shown, the smelting furnace for an inert gas environment of the present invention can be used according to the following steps: First, place the solid aluminum to be melted into the graphite crucible 140, and then put the sealing cover 210 on top. At this time, the sealing groove 211 of the sealing cover 210 coincides with the sealing ring 120 on the outer shell 110 and the extension plate 130, and the sealing ring 120 is embedded in the sealing groove 211 to achieve a seal (it can also be used with fasteners such as mounting block bolts for limiting the position). Then, the external vacuum pump is turned on, and the air in the cavity is removed through the vacuum tube 310. Then, the external gas supply pump is turned on, and the inert gas is replenished into the cavity through the gas supply tube 320. During the evacuation and replenishment of gas, the pressure sensor 410 and the oxygen concentration sensor 420 continuously monitor and transmit the data to the external control system (such as a PLC controller, which is not limited here, and because PLC is a mature technology, it will not be described in detail here). Then, the electromagnetic coil located between the outer shell 110 and the graphite crucible 140 is activated to melt metallic aluminum. During melting, the airflow drive mechanism 600 is activated, and the high-temperature gas inside the cavity enters the diversion pipe 740 through the first connecting pipe 131, provided that there is no blockage inside the first air outlet pipe 716: High-temperature gas with impurities circulates through the following channels: splitter pipe 740 - main pipe 714 - first outlet pipe 716 - collecting pipe 718 (low-temperature gas with impurities) - upstream of filter mechanism 500 - airflow drive mechanism 600 - downstream of filter mechanism 500 (low-temperature clean gas) - third outlet pipe 731 - fourth outlet pipe 734 - fifth outlet pipe 736 - cavity. Assuming there is no blockage inside the first airway 716: High-temperature gas with impurities circulates through the following channels: splitter 740 - differential pressure control valve 750 - auxiliary gas pipe 715 - second gas outlet 717 - manifold 718 (low-temperature gas with impurities) - upstream of filter mechanism 500 - airflow drive mechanism 600 - downstream of filter mechanism 500 (low-temperature clean gas) - third gas outlet 731 - fourth gas outlet 734 - fifth gas outlet 736 - cavity. In addition, because the heat exchange medium located in the preheating tank 735 and the cooling tank 711 is also flowing, its flow path is: cooling chamber - first water pipe 712 - circulating pump 720 - third water pipe 732 - preheating chamber - fourth water pipe 733 (with a one-way valve inside) - second water pipe 713 - cooling chamber. Finally, gas circulation is achieved (during circulation, the pressure sensor 410 and the oxygen concentration sensor 420 monitor the interior of the cavity in real time, and automatically turn on the external air pump to replenish inert gas in a timely manner based on the monitoring results).

[0043] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A smelting furnace for inert gas environment, comprising: a furnace body (100) for containing objects to be smelted; a sealing assembly (200) forming a cavity between the furnace body (100), and the cavity is divided into a first region and a second region; an air extraction and supply mechanism (300) comprising an air extraction part for extracting air inside the cavity and a gas supply part for injecting gas into the cavity; an air flow driving mechanism (600) having a high-pressure end communicating with the first region and a low-pressure end communicating with the second region; a heat exchange mechanism (700) having a cooling area for cooling the gas inside the high-pressure end and a preheating area for preheating the gas of the low-pressure end, and the heat exchange mechanism (700) can automatically switch the air flow path according to the pressure; a filtering mechanism (500) for filtering impurities in the cooled air flow path.

2. The smelting furnace for inert gas environment according to claim 1, characterized in that: The furnace body (100) comprises an outer shell (110), an extension plate (130), and a graphite crucible (140) with an opening and smelting material, the graphite crucible (140) is located inside the outer shell (110), and an electromagnetic coil is arranged between the graphite crucible (140) and the outer shell (110), the extension plate (130) is fixedly connected to one side of the upper end of the outer shell (110), and the extension plate (130) is connected to the high-pressure end and the low-pressure end of the heat exchange mechanism (700), and the outer shell (110) is connected to the sealing assembly (200) through a rotating part.

3. The smelting furnace for inert gas environment according to claim 2, characterized in that: The sealing assembly (200) comprises a sealing cover (210) rotatably connected to the outer shell (110) through a rotating part and a partition plate (220) fixedly connected inside the sealing cover (210), the first region and the second region of the cavity are located on both sides of the partition plate (220), the cavity is located between the sealing cover (210) and the outer shell (110) and the extension plate (130), a sealing groove (211) is formed on the side of the sealing cover (210) close to the outer shell (110), a sealing ring (120) is fixedly connected to the upper surfaces of the outer shell (110) and the extension plate (130), and the sealing ring (120) is sealed with the sealing groove (211).

4. The smelting furnace for inert gas environment according to claim 3, characterized in that: The air extraction end of the air extraction and supply mechanism (300) is a vacuum extraction pipe (310), the gas supply end of the air extraction and supply mechanism (300) is a gas injection pipe (320), and the vacuum extraction pipe (310) and the gas injection pipe (320) are fixedly connected to the sealing cover (210) and communicate with the cavity.

5. The smelting furnace for inert gas environment according to claim 4, characterized in that: The sealing cover (210) is provided with a monitoring mechanism (400) for monitoring the pressure inside the cavity and the oxygen content inside the cavity, the monitoring mechanism (400) comprises an air pressure sensor (410) for monitoring the pressure inside the cavity and an oxygen concentration sensor (420) for monitoring the oxygen content inside the cavity.

6. The smelting furnace for inert gas environment according to claim 5, characterized in that: The heat exchange mechanism (700) comprises: a cooling assembly (710) for cooling the air flow from the first region to the filtering mechanism (500); a preheating assembly (730) for preheating the air flow from the filtering mechanism (500) to the second region; a circulating pump (720) for driving the medium inside the cooling assembly (710) and the preheating assembly (730) to flow. A shunt pipe (740) is used to shunt the airflow from the first area to the filtering mechanism (500); A differential pressure control valve (750) is used to automatically change the airflow path inside the shunt pipe (740) according to the pressure.

7. The smelting furnace for inert gas environment according to claim 6, characterized in that: The cooling assembly (710) comprises a cooling tank (711), a first water pipe (712), a second water pipe (713), a main gas pipe (714), an auxiliary gas pipe (715), a first gas pipe (716), a second gas pipe (717), and a collection pipe (718). The cooling tank (711) is internally provided with a cold water cavity. The first gas pipe (716), the second gas pipe (717), and the collection pipe (718) are all inside the cold water cavity. One end of the cooling tank (711) is fixedly connected with the main gas pipe (714) and the auxiliary gas pipe (715). The other ends of the main gas pipe (714) and the auxiliary gas pipe (715) away from the cooling tank (711) are fixedly connected with the shunt pipe (740) and the differential pressure control valve (750), respectively. The same ends of the first water pipe (712) and the second water pipe (713) are fixedly connected with the cooling tank (711). The other end of the first water pipe (712) is fixedly connected with a circulating pump (720). The other end of the second water pipe (713) is connected with a preheating assembly (730). One end of the first gas pipe (716) and the second gas pipe (717) is fixedly connected with the cold water cavity of the cooling tank (711). The other ends of the first gas pipe (716) and the second gas pipe (717) are fixedly connected with one end of the collection pipe (718). The other end of the collection pipe (718) is fixedly connected with one end of the filtering mechanism (500). The shunt pipe (740), the main gas pipe (714), the first gas pipe (716), the collection pipe (718), and the airflow driving mechanism (600) are internally communicated. The shunt pipe (740), the differential pressure control valve (750), the auxiliary gas pipe (715), the second gas pipe (717), the collection pipe (718), and the filtering mechanism (500) are internally communicated.

8. The smelting furnace for inert gas environment according to claim 7, characterized in that: The preheating assembly (730) comprises a third gas pipe (731), a third water pipe (732), a fourth water pipe (733), a fourth gas pipe (734), a preheating tank (735) and a fifth gas pipe (736), the preheating tank (735) is internally provided with a preheating cavity, the fourth gas pipe (734) is located in the preheating cavity, one end of the third gas pipe (731) is connected with the filtering mechanism (500), the other end of the third gas pipe (731) is fixedly connected with one end of the preheating tank (735), the other end of the preheating tank (735) is fixedly connected with one end of the fifth gas pipe (736), the other end of the fifth gas pipe (736) is connected with the extension plate (130), both ends of the fourth gas pipe (734) are fixedly connected with both ends of the preheating cavity respectively, the filtering mechanism (500), the third gas pipe (731), the fourth gas pipe (734), the fifth gas pipe (736) and the cavity are in internal communication, the same end of the third water pipe (732) and the fourth water pipe (733) is fixedly connected with the outer wall of the preheating tank (735), the other end of the third water pipe (732) is fixedly connected with the end of the circulating pump (720) away from the first water pipe (712), the other end of the fourth water pipe (733) is fixedly connected with the end of the second water pipe (713) away from the cooling tank (711), and the inside of the fourth water pipe (733) is provided with a one-way valve for limiting the water flow direction, the cooling cavity, the first water pipe (712), the circulating pump (720), the third water pipe (732), the preheating cavity, the fourth water pipe (733) and the second water pipe (713) are in internal communication.

9. The smelting furnace for inert gas environment according to claim 8, characterized in that: The extension plate (130) is fixedly connected with a first connecting pipe (131) and a second connecting pipe (132) on the side away from the sealing cover (210), the first connecting pipe (131) and the second connecting pipe (132) are located on the two sides of the partition plate (220) respectively, one end of the shunt pipe (740) away from the main gas pipe (714) and the differential pressure control valve (750) is fixedly connected with the first connecting pipe (131), and one end of the fifth gas pipe (736) away from the preheating tank (735) is fixedly connected with the second connecting pipe (132).

10. The smelting furnace for inert gas environment according to claim 9, characterized in that: The filtering mechanism (500) comprises a first filter and a second filter, both ends of the first filter are fixedly connected with the end of the collecting pipe (718) away from the first gas pipe (716) and the air inlet end of the airflow driving mechanism (600) respectively, and both ends of the second filter are fixedly connected with the air outlet end of the airflow driving mechanism (600) and the end of the third gas pipe (731) away from the preheating tank (735) respectively.

Images