DEVICE FOR SEPARATING CAST ALUMINUM GAS AND IMPURITIES FIELD OF THE INVENTION The present invention relates generally to a device for melting an aluminum product, and more particularly to a device for separating gas and impurities from molten aluminum. BACKGROUND OF THE INVENTION In the process of manufacturing an aluminum alloy product by casting or mold casting, the aluminum ingot is melted and then injected into a molding tool. Molten aluminum is susceptible to a chemical reaction in which it reacts with atmospheric water vapor to produce hydrogen and aluminum oxide, as illustrated in the chemical equation 3H20 + 2A1? 3H2 + A1203. As a result, the molten aluminum is injected into the molding tool together with hydrogen and aluminum oxide, which can cause the aluminum product to have uneven structural strength and uneven surfaces. The conventional way to deprive molten aluminum of hydrogen and aluminum oxide is to use a quartz tube, which is installed in the bottom of a container containing the molten aluminum to inject chlorine or nitrogen into it. Meanwhile, the molten aluminum is manually stirred with an iron bar or carbon rod to promote the chemical reaction between hydrogen and chlorine or nitrogen, with the result, therefore, that the mass of aluminum oxide floats in the surface of the molten aluminum. The gas formed by the combination of hydrogen and chlorine or nitrogen is allowed to escape into the atmosphere while the aluminum oxide mass is removed to purify the molten aluminum. Said conventional way of depriving the molten aluminum of gas and impurities as described above is defective in its design insofar as it is dangerous for operator safety, and while the manual agitation of the molten aluminum is, at most, inefficient, and also in Both the stirring iron bar is vulnerable to corrosion, and even more so as the carbon stir bar is rather expensive. SUMMARY OF THE INVENTION It is therefore the primary objective of the present invention to provide a highly automated device for separating gas and impurities from molten aluminum. It is another object of the present invention to provide a device capable of stirring the molten aluminum efficiently and completely. It is still another object of the present invention to provide a device capable of injecting gas into the molten aluminum such that the gas diffuses through the molten aluminum to separate the hydrogen gas present therein.
The device of the present invention is composed of a driving portion, a transmission portion and a stirring portion. The drive portion has an output arrow while the transmission portion has a transmission arrow such that the axis of the transmission shaft is parallel to the axis of the output shaft, and that the transmission shaft is driven by the exit arrow. The stirring portion comprises a plurality of vanes, which are driven by the transmission shaft. Each of the vanes has an upper end surface and a lower end surface, which respectively form a predetermined angle with the axis of the transmission shaft. The transmission shaft is provided with an axial hole of a predetermined length. Each of the vanes is provided there with a channel to expel the gas contained in the molten aluminum. The features, functions and advantages of the device of the present invention will be more readily understood after a deliberate deliberation of the following detailed description of a preferred embodiment of the present invention together with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 shows a front view of the preferred embodiment of the present invention assembled in a crucible in which aluminum ingots are melted.
FIGURE 2 shows a sectional view of the preferred embodiment of the present invention. FIGURE 3 shows a sectional view taken along the direction indicated by a line 3-3 shown in FIGURE 1. DETAILED DESCRIPTION OF THE INVENTION As shown in FIGURES 1-3, a device 10 of the present invention for separating gas and impurities in molten aluminum is composed of a driving portion 12, a transmission portion 14 connected to the driving portion 12, and a stirring portion 16. The driving portion 12 comprises a motor 20 and a decelerating device. 22 connected to the motor 20 and provided with an exit arrow 24 that extends downwards and that has an appropriate length. The transmission portion 14 comprises a connection seat 40 and a transmission shaft 50. The connection seat 40 is fixed under the drive portion 12 and is provided with an axial bore 42 extending through the upper end and the lower end of the connection seat 40. The axial hole 42 is provided with an inner wall with an annular groove 44. Located between the inner wall of the axial hole 42 and the outer wall of the connection seat 40 is a gas pipe 46. The transmission shaft 50 is pivotally fitted at one end thereof with the axial bore 42 together with two bearings 51 and is provided with a C-shaped retaining ring 52 corresponding in location to the bearings 51. The transmission shaft 50 it is additionally provided there with a connection block 53 welded thereto to mount the outlet arrow 24 of the deceleration device 22. The transmission shaft 50 is provided with Additionally, a plurality of gas guide holes 56 correspond in location to the annular groove 44 in such a manner as to allow the axial bore 55 to be in communication with the gas conduit 46 through the annular groove 44 at the time. wherein the transmission arrow 50 is in motion. The stirring portion 16 comprises a main body 60 and eight vanes 70 attached to the periphery of the main body 60 of a different construction. The main body 60 is provided in its interior with a receiving cell 62 having an opening 64 in communication with the upper side of the main body 60. The transmission shaft 50 is secured to the receiving cell 62 by welding in such a way that the hole axial 55 of the transmission shaft 50 is in communication with the receiving cell 62. The vanes 70 are respectively provided with a channel 72, an upper end surface 74 and a lower end surface 76. The upper end surface 74 and the bottom end surface 76 are seen from the longitudinal cut of the vane 70. The normal line of the surface of the upper end 74 forms an angle with the axis of the transmission shaft 50. In operation, the transmission portion 14 is driven by the portion 12 so that the vanes 70 are activated to rotate in a positive direction in the molten aluminum contained in a crucible 90, as shown in FIG. FIGURE 1. Thus, the molten aluminum is agitated in the directions indicated by the arrows A that appear in FIGURE 1, which results, therefore, in the upward circulation of the aluminum oxide contained in the molten aluminum. As shown in FIGURE 3, each vane 70 is tilted in such a way that the molten aluminum is forced to move towards the bottom of the crucible 90, as indicated by the arrows B that appear in FIGURE 1 when the transmission shaft 50 it is driven by the drive portion 12 to rotate in the counterclockwise direction. Further, when the vanes 70 are operating to produce agitation, nitrogen gas may be introduced into the annular groove 44 through a hose 48 in communication with the gas conduit 46. The injected nitrogen gas is transported from the annular groove 44. through the gas guide holes 56, the axial hole 55, the receiving cell 62 and the channels 72 to be mixed with the molten aluminum that is being agitated. The hydrogen gas present in the molten aluminum is thus combined with the injected nitrogen gas.
Meanwhile, the aluminum oxide mass is forced to move towards the surface of the molten aluminum. The device 10 of the present invention is composed of a base 18 to facilitate the mounting of the device 10 in the crucible 90. The base 18 comprises a seat body 80 having three slots 81 which are located on the periphery of the body of the seat 80 so radiated in such a way that they form an angle of 120 degrees between them. Each of the three grooves 81 is provided therewith with an extension bar 82 capable of sliding along the axis direction of the slot 81. The extension rods 82 are respectively provided with a groove 83 parallel to the axis of the groove. extension bar 82. The seat body 80 is provided with three tightening screws 84 fastened thereto such that one end of each screw 84 is received in the groove 83 to locate the extension bar 82, which, therefore, , it can not move and exit the slot 81. Each extension bar 82 has one end, which is located outside the slot 81 and is provided with a leg 85 secured thereto. The extension rods 82 can be freely adjusted by the operator in such a way that the device 10 of the present invention can be mounted in crucibles of various sizes.