MXPA00012325A - Laser communication system and methods - Google Patents

Abstract

A laser communication system for full duplex wideband data transmission includes first and second terminals having dichroic wavelength-multiplexed optical systems wherein transmitted and received light are multiplexed along a path through the same aperture. The optical systems each preferably comprise a cassegrain receiver having primary and secondary mirrors for directing both transmitted and received laser light. Modulated laser light is generated by a high-power laser diode which is actively cooled by a thermoelectric cooler. A window in the housing, through which the modulated laser light travels, includes a transparent resistive coating to which electrical current is applied to control the temperature of the window. The aspheric primary mirror has a highly reflective surface, preferably a single-point diamond-turned mirror surface, formed on an aluminum substrate as a single piece.

Description

CONTINUOUS FUSION APPARATUS FOR LOW FUSION POINT METAL. IMPROVED CRISOL FOR SUCH APPARATUS AND FUSION METHOD USING SUCH APPARATUS BACKGROUND OF THE INVENTION FIELD OF THE INVENTION The present invention relates to an apparatus for continuously melting a low-melting metal, such as aluminum scrap, aluminum ingot and the like. More specifically, the invention relates to a continuous melting apparatus having a construction base in a crucible furnace. The present invention also relates to an improved crucible for such an apparatus. In addition, the invention relates to a method of fusion for use in the apparatus. s DESCRIPTION OF THE RELATED TECHNIQUE The collected empty aluminum cans are cut to an appropriate size of small pieces and then melted to be recycled as regenerated ingots. Aluminum scrap, such as shear, blades and the like discarded from factories and the like melt similarly to form regenerated ingot. Scrap, such as copper or similar cans can also be recycled, similarly. To promote such recycling, there has been a great demand to operate a melting apparatus facility at a very low cost to be easily implemented even by very small scale business establishments, autonomous agencies and the like. In a large-scale die-casting factory, molten metal such as aluminum melted by a concentrated melting furnace is received by a heat-resistant vessel, such as that called cauldron to be distributed to a clamp furnace as an installation auxiliary of several facilities of casting in the factory. If a large amount of ingot is melted every day to be distributed to several places in a large factory, such a system must be reasonable. However, in a small-scale recycling factory or a die-casting factory, where the quantity to be handled is not so great and the amount handled fluctuates significantly day by day, the concentrated melting furnace Large scale is inadequate for several reasons, however instead a compact and inexpensive device that is easy to operate and facilitates maintenance is more appropriate. Particularly, instead of the batch process, in which the operation to melt certain amount of material and the operation to take the molten bath from the furnace is repeated, it is necessary by all means the functionality to carry out continuously the fusion operation by a continuous supply of the scrap and the ingot one after the other. It is also desired that it be practical to keep the molten bath at a suitable temperature by continuously melting the material and easily removing the molten bath as required. In the prior art, as has been conventionally described, the conventional continuously retaining and melting apparatus which can be adapted to the needs set forth in the above in Japanese Examined Patent Publication No. Showa 56-17586 (hereinafter mentioned as the first prior art) and Japanese Examined Patent Publication No. Showa 62-23234 (hereinafter referred to as the prior art 2). The apparatus described in the first prior art is constructed with a cylindrical melting furnace and a holding furnace. An upper end opening of the melting furnace is a loading opening for the material, and the floor of the melting furnace slopes down towards the holding furnace to form a runner channel. The flame is blown into the furnace from a burner on a lower side wall of the melting furnace to heat the material in the melting furnace. The molten bath flows from the floor of the melting furnace to the holding furnace to be accumulated in the holding furnace. In the holding furnace, a dedicated burner is provided to heat the meniscus of the accumulated molten bath to maintain the molten condition. On the other hand, in the apparatus described in the second prior art, a material loading opening, a preheating chamber, a fusing chamber, a holding chamber and an extraction chamber are formed integrally with a refractory material. The flame of the fusion burner is blown into the preheating chamber and the melting chamber. Then, the material in the preheating chamber is heated and melted. The molten bath flows from the preheating chamber to the melting chamber and then to the holding chamber to accumulate in the holding chamber and the extraction chamber. A dedicated burner is provided in the retention chamber to heat the meniscus of the accumulated molten bath so that the heat maintains the molten state. The holding chamber and the extraction chamber are communicated with each other in the lower portions thereof so that the same level of the molten bath can accumulate in the extraction chamber. In a roof portion of the extraction chamber, an extraction opening with a cover is open to allow extraction of the molten bath. In the type where the flame of the burner acts directly on the Aluminum scrap, ingot or the like for melting, as in the first and second prior art techniques, has a disadvantage that increased loss due to oxidation can be caused. Particularly, in the case of aluminum scrap cut into small pieces, they tend to be subjected to a combustion flame inside the furnace and to be oxidized to degrade the melting performance significantly. Also, hydrogen gas can be absorbed in the molten bath to cause degradation of the quality of the molten bath. Also, in the case of apparatuses similar to those in the first and second prior art, the ceramic planks, the heat insulation boards or the lightweight porous heat insulation bricks are fitted on the outside as a material for forming the kiln wall of cylindrical melting furnaces, holding furnaces or mixed type integrated kilns. And heat insulating and refractory chamotte bricks are additionally placed. On the portion to make contact directly with the molten bath, a brick with a high content of alumina is often used. To join the refractory pieces, the homogeneous refractory mortar with the brick is used mixed with water. In such typical furnace construction, the reaction may be caused between the material of the furnace wall and the molten aluminum bath to grow the native aluminum oxide agglomerate on the liner wall. Such agglomerate of native aluminum oxide has a very high hardness to cause difficulty in the removal. If an attempt is made to remove the native aluminum oxide agglomerate by force, a part of the liner may be damaged simultaneously. If it happens, there is no other option, but change the complete furnace which requires a huge cost. On the other hand, if such an agglomerate of native aluminum oxide is mixed in the molten bath, this can be a cause of defective products. Therefore, the reduction of the agglomerate of native aluminum oxide is important to improve the performance of the products. However, as long as the general refractory is used as the furnace wall, the problem due to the agglomeration of native aluminum oxide is unavoidable.

BREV7E DESCRIPTION OF THE INVENTION The present invention has been delineated in view of the problems set forth in the foregoing. It is an object of the present invention to provide a continuous low melting metal retaining and melting apparatus which satisfies the following points (a) to (e): (a) that it is implemented in a compact and inexpensive manner and that it is easy to manage or perform maintenance; (b) that is capable of continuously melting the scrap or aluminum ingot load one after the other; (c) that is capable of retaining the molten bath continuously at an appropriate temperature and that it is easy to remove the molten bath as required; (d) that the loss due to oxidation is very small and the mixed amount of hydrogen in the molten bath is also very small because the material, such as scrap or aluminum ingot, is not directly subjected to the flame of the burner; and (e) that the native aluminum oxide agglomerate due to the reaction of the molten aluminum bath and the material of the furnace wall is avoided. The present invention is basically directed to a continuous melting apparatus for a low melting metal, developed from crucible furnaces and comprises: a main body of a melting furnace forming a combustion chamber surrounded by a refractory lining; a crucible formed with a female screw hole in an appropriate position of a body and housed in the central portion of the combustion chamber; a burner provided on a portion of the side wall of the main body of the melting furnace for heating the crucible in the combustion chamber; and a receptacle for receiving a molten bath flowing outwardly through the female screw hole of the crucible. It is preferred to implement the invention by appropriately adding the following elements to the basic construction stated in the foregoing. (1) A crucible base is fixed on a floor of the combustion chamber and the crucible is mounted on the base of the crucible. (2) In the aspect of (1), the floor portion of the combustion chamber serves as a first receptacle receptacle for accumulating the molten bath flowing through the female receptacle hole, and the first receptacle receptacle communicates with a second receptacle receptacle located outside the receptacle. combustion chamber. In this case, the "second receptacle container is provided with a retention heater to heat the molten bath received therein. (3) A tundish is connected to the external part of the female screw orifice of the crucible and the molten bath which flows out through the female screw hole it is guided to the receptacle located outside the combustion chamber by means of the tundish. (4) In the aspect of (3), the receptacle comprises a body of the holding furnace which forms a heating chamber surrounded by a refractory lining, a holding crucible provided in the central portion of the heating chamber, and a heater of retention provided on the portion of the side wall of the main body of the retention furnace and heating the retention crucible. (5) In the aspect of (3), a plurality of receptacles are provided, and the trough is constructed to distribute the molten bath flowing through the female screw hole to the respective plurality of receptacles. (6) A baffle plate is disposed within an appropriate distance to the inlet of the female screw hole. Alternatively, an open pipe 51 extending downwardly from the female screw hole is located in the crucible. In addition, alternatively, a rising direction channel 52 is connected to the external part of the female screw hole. They are provided in order to prevent pieces of metal from flowing from the crucible. (7) A window that unloads pieces of metal is formed in the portion of the body of the crucible in a different orientation position with respect to the hole in the crucible. female thread, with the lower edge located at the level close to the female screw hole and being elongated in the width direction, and a working opening for unloading the piece of metal is formed on the side wall portion of the main body of the furnace of fusion in a spatially continuous position with respect to the unloading window of pieces of metal. (8) In the aspect of (1), an air flow hole is formed to extend laterally at the base of the crucible. On the other hand, in the present invention, to build the above continuous melting apparatus, a crucible has been developed as an upwardly open refractory vessel comprising: a female screw hole formed through a body portion in a position lower proper with respect to the upper edge of the container; a locking member provided in the portion of the female screw hole and which prevents pieces of metal from flowing out through the female screw hole, and a metal pieces unloading window formed through the body portion in a different orientation position with respect to the female screw hole, which has a lower edge at a level close to the entrance of the female screw hole, and being elongated in the width direction. In the crucible as set forth above, it is preferred that the unloading window of pieces of metal be defined by a recess cut reaching the upper end thereof with respect to the upper edge of the container. Also, a channel can be integrally connected to the outside of the metal pieces unloading window, the channel can be provided in an upward inclination from the lower edge of the metal pieces unloading opening. Also, in the present invention, as a method for melting and separating aluminum from a material containing aluminum and other metals having higher melting point, using a continuous melting apparatus as set forth above, wherein an amount Appropriate material is additionally loaded into the crucible at appropriate times to keep the unmelted aluminum in a molten aluminum bath in the crucible, it has been developed.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be understood more fully from the detailed description given in the following and from the attached drawings of the modality Preferred of the present invention, which, however, should not be taken as limiting the present invention, but are for purposes of explanation and understanding only. In the drawings: Figure 1 is a longitudinal section of the first embodiment of the continuous melting apparatus according to the present invention; Figure 2 is a cross section of the apparatus of Figure 1; Figure 3 is a longitudinal section of the apparatus shown in Figure 1 as taken along line A-A of Figure 2; Figure 4 is a front elevational view partially in section showing a modification of a window unloading metal pieces in the apparatus of Figure 1; Figure 5 is a section showing in diagrammatic form a -modification of a locking member provided erf in the vicinity of a tap hole of a crucible of the apparatus in Figure 1; Figure 6 is a cross-section showing a discharge operation of pieces of metal in the apparatus of Figure 1; Figure 7 is a longitudinal section of a modification of a crucible of the apparatus of Figure 1; Figure 8 is a cross section of the second embodiment of a continuous melting apparatus according to the present invention; Figure 9 is a longitudinal section of the apparatus of Figure 8; Figure 10 is a cross section of the third embodiment of the continuous melting apparatus according to the invention; Figure 11 is a longitudinal section of the apparatus of Figure 10; Figure 12 is a section showing an example of improvement of a crucible base with respect to the apparatus of the present invention; Figure 13 is a longitudinal section of the fourth embodiment of a continuous melting apparatus according to the present invention; Figure 14 is a cross section of the apparatus of Figure 13; Fig. 15 is a longitudinal section of the fifth embodiment of a continuous melting apparatus according to the present invention; Figure 16 is a longitudinal section including a stirring apparatus that can be installed in the apparatus of Figure 15; Figure 17 is a longitudinal section of the sixth embodiment of the continuous melting apparatus according to the present invention; Figure 18 is a longitudinal section of the seventh embodiment of the continuous melting apparatus according to the present invention; Figure 19 is a longitudinal section of the eighth embodiment of a continuous melting apparatus according to the present invention; and Figure 20 is a temperature elevation curve (time frame) in a continuous melting method embodiment according to the present invention.

DESCRIPTION OF THE PREFERRED MODALITY The present invention will now be discussed in detail in terms of the preferred embodiment of the present invention with reference to the accompanying drawings. In the following description, numerous specific details are set forth to provide a total understanding of the present invention. It will be obvious, however, for those skilled in the art that the present invention can be practiced without these specific details. In another case, well-known structures are not shown in detail to avoid unnecessary darkness of the present invention.

- A Series of Modalities of the First Type - The construction of one embodiment of a crucible and a crucible furnace according to the present invention are shown in Figures 1, 2 and 3. First, the construction of the crucible 1 will be discussed only. The crucible 1 is formed of graphite, graphite / silicon carbide or graphite / clay and in a ladle configuration with a large opening in the upper portion and a flat bottom for self-support. A body of the crucible 1 is formed with a plug hole 2 in a position below the end of the opening with an appropriate distance. The male hole 2 is an elongated rectangular shape with the width direction, but has a relatively small dimension. As a blocking member to prevent pieces of metal from being discharged through the male hole 2, the embodiment shown employs a baffle plate 3. The body of the crucible 1 has a substantially cylindrical surface. On the internal part of the body in a position where the tap hole is formed, the deflector plate 3 of the graphite crucible material is formed integrally. Both side portions of the baffle plate 3 are connected to the body portion, but the remaining portion thereof is placed away from the inner surface of the body portion. Particularly, in the position of the male hole 2, the distance between the baffle plate 3 and the body portion is maximized. As shown in the planar construction of Figure 2, as seen from the center of the crucible 1, a window 4 for unloading pieces of metal is formed through the body portion in a position with angular deviation of 90 ° from the orifice. 2 of male The window 4 for unloading pieces of metal has a rectangular shape elongated in the width direction. The dimension of the window 4 for unloading metal pieces is much greater than that of the male hole 2. The position of the lower edge of the window 4 for unloading metal pieces is fixed to a position slightly higher than the position of the lower edge of the male hole 2. It should be noted that, as in the embodiment illustrated in Figure 4, when the window 4 for unloading pieces of metal is constructed to reach the upper edge thereof with respect to the upper edge of the crucible 1, the window 4 for unloading pieces of metal means a recess cut. With such construction, the production of the crucible can be facilitated. Next, it will be discussed with respect to the crucible furnace. In the center of a combustion chamber 6 surrounded by a refractory lining of a furnace body, a crucible base 7 is fixed. On the crucible base 7, the crucible 1 constructed as established in the above is assembled. By means of a burner 8 provided through the holes in the side wall portion of the furnace body 5, the crucible base 7 and the crucible 1 in the combustion chamber are heated. In a furnace door 9 in the upper portion of the furnace body 5, a material loading opening is provided. A diameter of the material loading opening is smaller than the diameter of the crucible 1. The crucible 1 is located just below the loading opening. Through this loading opening, the scrap aluminum and successively in this way is loaded into the crucible 1. On the other hand, as shown in Figures 2 and 3, when the crucible 1 is correctly fixed in a predetermined orientation in the combustion chamber 6, a working opening 10 for removing the pieces of metal, formed in the side wall portion of the furnace body 5 and the window 4 for unloading pieces of metal becomes consistent in such a way that both are connected spatially During other operations than the work of removing pieces of metal, the working opening 10 is closed by a door 11. On the other hand, a floor of the combustion chamber 6 is provided with a downward inclination towards the opposite side with respect to the position of the burner 8. On the lowest part of the ground, a hole is formed that is going to be a runner channel extended externally. The channel The runner communicates with a retention chamber 13 of the molten bath 12. Next, as discussed in detail, the molten bath to be discharged from the male orifice 2 of the crucible 1 flows down to the combustion chamber 6 for flow along the inclination of the floor to accumulate in the holding chamber 13. Namely, the floor portion of the combustion chamber 6 serves as a first receptacle receptacle for receiving the molten bath flowing outwardly through the male orifice 2. The first receptacle receptacle communicates with the retention chamber 13 as a second receptacle receptacle. It will be discussed with respect to the method of use and operation of the crucible and crucible kiln constructed as stated in the above. The aluminum material, such as an empty aluminum can properly cut into small pieces, is loaded into the crucible 1 through a loading opening of the oven door 9, and then the crucible 1 is heated by the burner 8. By this heat, the aluminum material is melted in the crucible 1. A combustion gas is discharged through a throat between the oven door 9 and the crucible 1. It should be noted that, in order to promote the fusion of the aluminum, the aluminum material and the molten bath should be agitated with a stirrer.

Because the male orifice 2 is located in the intermediate position at an appropriate height of the body portion of the crucible 1, when a certain amount of the molten bath accumulates within the crucible, the molten bath flows out through the orifice 2. from male to chamber 6 d combustion to flow in holding chamber 13. In this way the molten bath accumulates in the holding chamber 13. Although not illustrated, to avoid cooling of the molten aluminum bath in the holding chamber 13, it is desirable to heat the molten bath 12 from the top by attaching an auxiliary burner to the body 5 of the furnace. As stated in the foregoing, the molten aluminum bath in an amount corresponding to the position of the male hole 2 accumulates the crucible 1. Therefore, the aluminum material loaded from the upper part makes contact with the molten bath and It melts efficiently. Depending on the melting rate within the crucible 1, the aluminum material is sequentially loaded into the crucible 1 to effect the "continuous melting process which is different from the batch process carried out by the conventional crucible furnaces. Effectively the heat discharged from the loading opening of the oven door 9, the aluminum material is effectively preheated by the ascending process of immersing in the molten bath in the crucible in such a way that the deposition, As moisture or oil resides on the aluminum material, such deposition can be removed - as it passes through the preheating zone. In this way, the possibility of provoking a strong reaction, such as the phreatic explosion, is reduced to achieve high security. Additionally advantageously, the preheating zone has a non-oxidative atmosphere which leads to a very small oxidation loss. On the other hand, the construction where the baffle plate 3 is provided on the inner surface of the male hole 2 to protect the tap hole 2 slightly distanced away from it in such a way that the male hole 2 can not be blocked by the aluminum material loaded in the crucible 1. Around the surface of the molten bath, the pieces of metal float with the aluminum material that has not yet been melted or with the aluminum material in the form of sorbet. If these flows together with the bath, fused in the male hole 2 to block the male hole 2, the meniscus of the molten bath rises to make the molten bath mixed with the pieces of aluminum flow over through the large opening to the window 4 for unloading pieces of metal. The member to avoid this is the baffle plate 3 as the blocking member. It should be noted that the mode of the locking member is not limited to the baffle plate 3.

For example, as shown in Figure 5 (a) open pipe 51 (this is the blocking member) extending downwardly from the tap hole 2 can be provided in the crucible. Or for example, as shown in Example 5 (b), it is also possible to mount a channel 52 as the blocking member is provided upwardly in the external position of the male hole 2. When a large quantity of pieces of metal accumulate around the surface of the molten bath in the crucible, the working opening 10 is opened by the opening of the door 11 in the side portion of the body 5 of the furnace to effect the unloading operation. of the pieces of metal around the surface of the molten bath through the window 4 of discharge of pieces of metal. Because the working opening 10 is located on the side surface of the furnace body, the worker is not subjected to extreme heat, even if the metal pieces unloading operation is performed manually. The operation of unloading pieces of metal is done in the following way. The meniscus of the molten bath is placed at a level slightly lower than the lower edge of the window 4 for discharging pieces of metal from the crucible 1. The piece of metal 16 accumulates around the meniscus. Therefore, as shown in Figure 3, inserting a receptacle 14 of pieces of metal into a shape similar to a dust boot through the work opening 10, and a metal scraper 15 with a long bar is inserted into the crucible to sweep and pick up the pieces of metal from the meniscus of the molten bath over the receptacle 14 of pieces of metal. By repeating this procedure, the meniscus of the molten bath is cleaned. Figure 6 is a diagrammatic illustration showing the case where the sweeper 15 of pieces of metal is mechanically reciprocal. In this example, by means of a belt mechanism driven in the forward direction and in the reverse direction by means of the motor 19, the sweeper 15 of metal pieces is driven. Another embodiment of the crucible 1 and the crucible furnace employing the same according to the present invention is illustrated in Figure 7. In the crucible 1 of Figure 7, a channel 18 is integrally connected to the exterior of the window portion. 4 discharge of pieces of metal. The channel 18 is provided in ascending inclination from the lower edge of the window 4 for unloading pieces of metal. In this embodiment, even when the amount of material charge in the crucible 1 increases abruptly to exceed a quantity of female thread through the female screw hole 2, or even when the molten bath boils by the flow process or so successively to a temporary position the meniscus of the bath fused to a position higher than the female screw hole 2, the piece of metal is prevented from flowing to the combustion chamber 6 together with the molten bath for the presence of the rising channel 18. Advantageously, because the channel 18 extends from the internal part of the furnace as shown in Figure 7 through the working opening 10 of the furnace body 5, the operation is easily performed to discharge the pieces of metal out of the furnace. oven.

- A Series of Modalities in the Second Type - The other embodiment of the present invention is illustrated in Figures 8 and 9. The embodiment shown of the continuous melting apparatus is constructed with an individual melting furnace A as a main body of the apparatus and an individual holding furnace B as a receptacle container located outside the previous combustion chamber. The melting furnace A includes a main body 305 of the melting furnace which forms a combustion chamber 306 surrounded by a refractory lining 392, a crucible base 307 fixed in the center of the combustion chamber 306, a melting crucible 301 formed with a female screw hole 302 at an intermediate height of the body portion, and a melting burner 308 provided on the side wall portion of the main body 305 of the oven melting to heat the crucible 301 from the circumference. Base 307 of crucible and crucible 301 are formed of graphite, graphite / silicon carbide or graphite / clay. On the side wall portion of the main body 305 of the oven, a cleaning opening 367 is formed. On the main body 305 of the melting furnace, a door 309 of the donut-shaped oven is placed. The holding furnace B includes a main body 395 of the holding furnace which forms a heating chamber 396 surrounded by a refractory lining 382, a holding crucible 391 fixed in the central portion of the heating chamber 395, a heating burner 398 provided on the side wall portion of the main body 395 of the holding furnace to heat the crucible 391 from the circumference. The crucible 391 is formed of graphite, graphite / silicon carbide or graphite / clay. On the side wall portion of the main body 395 of the holding furnace, a cleaning opening 377 is formed. On the main body 395 of the holding furnace, an oven door 399 is placed in the form of a donut plate. It should be noted that the holding burner 398 can be replaced with other heating equipment, such as an electric heater or the like. A molten bath passage 360 connecting the melting furnace A and the holding furnace B is a channel in section formed through a graphite crucible material. The molten bath passage 360 is formed through the side wall of the main body 305 of the furnace. In an end portion of the molten bath passage 360 is connected to the external part of the female screw hole 302 of the melting crucible 301 in the melting furnace A. The other end of the passage 360 of the molten bath is supported above the door 399 of the holding furnace B. In this way, the tip end of the molten bath passage 360 is located in opposition to the upper opening of the holding crucible 391. The molten bath passage 360 has a slightly downward inclination from the melting furnace A to the holding furnace B. The material, such as aluminum scrap, is continuously loaded into the crucible 301 of the melting furnace A with heating by the melting burner 308. By this heat, the aluminum material in the crucible 301 melts from the bottom side. The combustion gas is discharged through a throat between the furnace door 309 and the crucible 301. It may be possible to agitate the aluminum material and the molten bath 312 by means of a stirrer to promote melting of the aluminum material. Because the hole 302 is threaded female it is located in the intermediate height position of the body portion of the melting crucible, when a certain amount of the molten bath 312 accumulates within of the crucible, the molten bath 312 flows out through the female screw hole 302 to flow downwards to the crucible 391 of the holding furnace B through the molten bath passage 360. By heating the crucible 391 appropriately by the burner 398 of the holding furnace B, the molten bath accumulated in the crucible 391 can be maintained at a suitable temperature. The molten bath accumulated in the holding crucible 391 can be extracted as required. The extraction operation and the continuous melting operation in the melting furnace A can be carried out in parallel without any obstruction. As stated in the above, because the molten aluminum bath accumulates in the crucible in an amount corresponding to the position of the female screw hole 302, the aluminum material loaded from above can be melted efficiently by placing it in contact with the accumulated 312 molten bath. By continuously loading the aluminum material depending on the melting rate in the crucible 301, the continuous melting process, different from the batch process as carried out in conventional crucible furnaces, can be carried out. On the other hand, by using the heat discharged from the loading opening of the oven door 309, the aluminum material is effectively preheated by the process of submerging in the molten bath in the crucible in such a way that the deposition such as moisture or oil resides on the aluminum material, such deposition can be removed while passing through the preheating zone. Therefore, the possibility of causing a strong reaction, such as the phreatic explosion is reduced to achieve high security. On the other hand, the preheating zone is in a non-oxidative atmosphere to have very little oxidation loss. Also, little hydrogen can be mixed in the molten bath. Another embodiment of this type is illustrated in Figures 10 and 11. The embodiment shown of the continuous melting apparatus is constructed with an individual melting furnace A and two holding furnaces Bl and B2 arranged in close proximity to one another. The construction of the melting furnace A is the same as in the previous mode, and the constructions of the firing furnaces Bl and B2 is substantially the same as in the holding furnace B in the previous embodiment. The molten bath passage 460 differs from the previous embodiment and is constructed to connect the individual melting crucible 401 and two retaining pots 491 to distribute the molten bath. Specifically, the molten bath passage 460 is formed in the T-shaped configuration such that the flow of molten bath out of the melting crucible 401 flows distributively into the crucibles 491 of retention of the left and right retention furnaces Bl and B2. By providing an appropriate division in the branching portion of the passageway 460 of the molten bath, the molten bath can be selectively supplied to the holding furnaces Bl and B2. In this case, once the crucible of the holding furnace Bl is filled with the molten bath, the molten bath supply passage changes towards the side of the holding furnace B2. Then, the filled retention furnace Bl moves to the position requiring the molten bath by conveying means, such as a forklift or the like. Namely, the holding furnace can serve as a cauldron. Therefore, a very reasonable work procedure can be established.

- Improved Crucible Base - Next, the preferred form of the crucible base in the continuous melting apparatus according to the present invention will be discussed. In the continuous melting apparatus shown in Figures 1 or 8, with respect to an annular space between the inner peripheral wall of the combustion chamber and the outer peripheral surface of the base of the crucible, a flame of the burner is blown in the direction tangential. The flame from the burner propagates along the floor of the combustion chamber to heat surrounding the side surface portion of the bottom surface of the crucible. Accordingly, the temperature of the crucible raises the temperature of the lower side. However, in a strict sense, the temperature rise in the central portion of the bottom of the crucible is not necessarily the fastest. Because the center of the bottom of the crucible is in contact with the base of the crucible protects the heat of the flame by means of the base of the crucible causes delay in raising the temperature in the center of the bottom in comparison with the side wall of the lower part of the external portion of the crucible of the base of the crucible. In particular, when a refractory fiber is placed between the base of the crucible and the crucible, the heat protection of the center of the bottom of the crucible becomes more significant. By providing superior efficiency of the thermal conduction of the center of the bottom of the crucible, the melting rate of the metal in the crucible can be higher to save fuel. Also, because the heat of the crucible base increases to improve the degassing effect by the natural convection of the molten bath. On the other hand, in the event that the base of the conventional crucible is of cylindrical shape, it has a superior heat protection effect to cause the delay in temperature rise in the lower portion of the crucible.

To solve the problem set forth in the above, the improved form of the crucible base as shown in Figures 12 (a) to 12 (e) is described. The base mode 507 of the crucible shown in Figure 12 (a) is constructed with a closed cylindrical body of upper end, and two holes 597 of air flow. These air flow holes 597 reach the hollow portion 590 of the inner part. When this crucible base is applied to the crucible furnace shown in Figure 1, the flame or combustion gas enters the hollow portion 590 through the air flow hole 597 to make the rate of rise of the temperature of the crucible. the base 507 of the upper crucible. Consequently, the large amount of calories is transmitted to the center of the bottom of the graphite crucible from the base 507 of the crucible to promote the temperature rise of the bottom of the crucible. In the crucible base mode as shown in Figure 12 (b), in addition to the air flow hole in the lateral alignment in the embodiment of Figure 12 (a), two air flow holes 594 that are they intersect in a transversal way they form. Because the number of passages of the air flow increases, the heat capacity of the crucible base per se decreases, and can improve the effect of introducing combustion gas.

The mode of the base of the crucible shown in Figure 12 (c), is formed with a hole 593 of air flow that extends vertically in the portion of the sky of the base of the crucible, in the construction of the modality shown in Figure 12 (a). Therefore, by means of the combustion gas introduced into the central portion, the base of the crucible can be heated efficiently by the combustion gas. The crucible base of the embodiment shown in Figure 12 (d) is formed with the airflow passage extending laterally in the straight cylindrical portion through which the hollow portion 592 extends vertically, corresponding to that of the diameter of the air flow hole 593 shown in the embodiment of Figure 12 (c) is increased in the mode. The base of the crucible of Figure 12 (e) is formed with a hole 589 of air flow extending in the lateral direction in the solid cylindrical body. On the other hand, on the upper end surface, the central recess portion 587 and the radial recess 588 are formed. Because the airflow passage 589 is present, an effect is achieved to promote the rise in temperature at the base of the crucible. In spite of this, because the radial recess 588 and the central recess portion 587 are present, the combustion gas directly promotes the rise of temperature of the contact portion of the base of the crucible and the graphite crucible and the base of the crucible.

-Other Modality- The construction of other embodiments of the present invention is shown in Figures 13 and 14. A crucible base 607 is fixed in the center of the combustion chamber 606 surrounded by the refractory lining of a furnace body 605. On crucible base 607, a crucible 601 of graphite is mounted. By means of a burner 608 provided in the hole of the side wall portion of the furnace body 605, the crucible 601 and the crucible base 607 in the combustion chamber 606 are heated. In two portions of the side wall portion of the body 605 of the oven, the cleaning openings 620 are provided in two positions. On the other hand; a table 621 extending over the upper portion of the body 605 of the furnace is provided. In table 621, the aluminum charger 622 and agitator 623 are mounted. A female screw hole 602 is formed through the intermediate height portion of the crucible body 601. Within the crucible 601, a baffle plate 603 is provided in the portion where the female screw hole 602 is formed. The deflector 603 covers the female screw hole 602 in a position suitably spaced from the opening surface of the female screw hole 602. In addition, the lower end of the baffle plate 603 suitably extends beyond the lower end position of the female screw hole 602. In practice, the graphite crucible is a cylindrical shape of 1100 mm in height. An individual female screw hole 602 of 60 mm in height x 100 mm in width is substantially formed in the intermediate body portion. The deflector plate 603 in the embodiment shown, is mounted by hooking on the upper edge of the crucible 601 and hangs vertically within the crucible 60-1. Between the surface of the baffle plate 603 and the opening surface of the female screw hole 602, a throat in the length of 30 mm is provided. In addition, the lower end of the baffle plate 603 extends approximately 80 mm lower than the lower end of the female screw hole 602. Further, as shown in Figure 14, both end portions of baffle plate 603 are bent towards the wall surface of crucible 601 so that both ends are in contact on the inner peripheral surface of crucible 601. The material 624 of aluminum, such as scrap aluminum cut into small pieces is charged through the upper opening in the crucible 601, and heated from the outer periphery of the crucible 601. By this heat, the aluminum material in the crucible 601 melts from the lower portion. The combustion gas is discharged from the opening portion 626 of the oven door 609 through a throat between the oven door 625 and the crucible 601. To promote melting of the aluminum 624 material, a 623 agitator device is used. , in which the aluminum material 624 and the molten bath are mixed by stirring. Because the female screw hole 602 is present in substantially the intermediate position of the crucible body 601, the molten bath in the crucible 601 accumulates in a certain amount. Then, the molten bath flows outwardly externally from the crucible 601 and accumulates in the holding chamber 613 in the body 605 of the furnace. Within the body 605 of the furnace, a molten bath passage extending from the combustion chamber 606 to the holding chamber 613 and then to the female tundish 627 is formed. The molten bath 612 of aluminum accumulated in the holding chamber 613 is discharged out of the furnace from the female tundish tundish 627 by the effect of grammatical force. To prevent cooling of the molten aluminum bath 612 accumulated in the holding chamber 613, an auxiliary burner 628 is provided in the body 605 of the furnace to heat the molten bath 612 from above.

As discussed in the foregoing, the molten aluminum bath of the amount corresponding to the position of the female screw hole 602 is accumulated within the crucible 601. The aluminum material 624 loaded from above is melted efficiently upon contacting the accumulated molten bath. The upper space from the meniscus of the molten aluminum bath in the crucible becomes a preheating zone. The charged aluminum material 624 accumulates in the preheating zone and melts in the molten bath from the lower portion gradually. On the other hand, a construction of the additional embodiment is illustrated in Figure 15. A crucible base 707 is fixed in the center of the combustion chamber 706 surrounded by the refractory lining of the body 705 of the furnace. On the base 707 of crucible, a crucible 701 of graphite is mounted. By means of a burner 708 provided in the bore of the side wall portion of the body 705 of the furnace, the crucible 701 and the crucible base 707 in the combustion chamber 706 is heated. The uppermost space of the combustion chamber 706 communicates with a funnel 730 through a gas conduit 729. In two portions of the side wall portion of the body 705 of the oven, the cleaning openings 720 are provided in two positions. A female screw hole 702 is formed through the crucible in the vicinity of the bottom. In practice, Graphite crucible 701 has a cylindrical shape with a height of 1100 mm. On the peripheral surface, slightly above the lower surface, four portions of the female screw holes 402 of diameter are formed. The height of the base 707 of the crucible is 350 mm. The aluminum material 724 is loaded from the upper opening in the crucible 701, the crucible 701 is heated from the outer periphery by the burner 708. By this heat, the aluminum material 724 melts from the lower portion of the crucible 701. In the vicinity of the lower part of the crucible 701 the female screw hole 702 is formed. Therefore, the molten aluminum bath in the crucible 701 is discharged out of the crucible through the female screw hole 702 by the action of gravity and accumulates in the lower part of the combustion chamber 706 of the body 705 of the furnace . The internal structure of the body 705 of the furnace formed the molten bath passage that extends from the combustion chamber 706 to the female tundish 727. The molten bath 712 of aluminum accumulated in the lower part of the combustion chamber 706 is discharged out of the furnace from the female tundish trough 727 by the action of gravity. To prevent cooling of the molten bath 712 of aluminum in the molten bath passage from the combustion chamber 706 to the female tundish 727, the body 705 of the furnace is heated when fixing the auxiliary burner 729. Depending on the melting rate within the crucible 701, the aluminum material 724 is loaded in the crucible 701 gradually to effect the continuous melting process different from the batch process as is done by conventional crucible furnaces. The aluminum material 724 loaded in the crucible 701 is not directly in contact with the molten bath, but gradually falls down to be melted therewith being heated in the upper space of the crucible 701. Mainly, the space of the upper portion of the The crucible serves as a preheating zone and the space in the lower portion serves as a melting zone for the melting to progress. Even when the deposition, such as moisture or oil on the aluminum material 7 resides, such deposition can be removed while passing through the heating zone. Because a large amount of molten bath is not present in the -fusion zone, the possibility of causing a strong reaction, such as groundwater explosion, is reduced to achieve high safety.

On the other hand, the preheating zone is in a non-oxidative atmosphere to have very low oxidation loss. Another modality of this type will be discussed. When the heat transfer to the upper space (zone of preheating) is not efficient, it is effective to agitate the aluminum material 724 by means of the agitator 723 as in the embodiment illustrated in Figure 16. On the other hand, in the embodiment illustrated in Figure 17, the smallest crucible 732 that has the smaller diameter than the crucible 701 is fixed upwardly in the center of the crucible 701 through the base 733. Within the smaller crucible 732, the molten aluminum bath and a dip heater 735 are positioned in such a way that the material 724 of Aluminum is in the space between the crucible and the smallest crucible. In the embodiment of Figure 16, a degassing hole 731 is formed through the upper peripheral wall of the crucible 701. The degassing hole 731 is opposite in the vicinity of the gas conduit 729 connected to the funnel 730. With the construction discussed in the foregoing , black smoke caused in the crucible 701 enters the combustion chamber 706 to mix with the combustion gas to be discharged into the funnel 730 through the gas conduit 729. A non-oxidative atmosphere can be maintained within the crucible 701. On the other hand, in the embodiment of Figure 18, a cylindrical pipe 737 of iron of 1200 mm height is provided to be continuous with the upper opening of the crucible 701. With this construction, the preheating zone in the crucible extends upwardly. to improve the effect of removal of the residual deposition on the 724 aluminum material. In addition, the non-oxidative atmosphere of the preheating zone is established with greater certainty. An embodiment having a molten bath extraction passage different from that of the previous embodiment is illustrated in Figure 19. In this embodiment, a female screw hole 802 (not shown) is defined in the center of the bottom of the crucible. 801. In a base 807 of the crucible, a female screw opening 842 directly communicated with the female screw hole 802 of the crucible is defined. On the other hand, the base 807 of the hollow crucible per se extends through the lower part of the body 805 of the furnace to oppose the tundish 860 disposed below the body 805 of the furnace. In addition, a smaller crucible 840 having a smaller diameter than the crucible 801 is arranged in a head shape to close the female screw hole 802 in the center of the crucible 801. A set of holes 841 formed in the vicinity of the edge of the crucible. the lower opening of the smaller crucible 840 serves as the passages of the molten bath connecting the space defined between the crucible 801 and the smaller crucible 840 and the female screw hole 802. Mainly, the molten aluminum melt bath in the crucible 801 flows through the opening 841 of the smaller crucible 840 to the female screw hole 802. in the center of the bottom of the crucible 801 to the base 807 of the crucible of the hollow pipe form - and to the tundish 860. The molten bath is supplied from the tundish 860 to the holding furnace 895 to accumulate therein. In the holding furnace 895, a dividing wall 843 and an immersion heater 844 are provided. Above the tundish 860, a gas conduit 845 communicated with the combustion chamber 806 is provided to prevent cooling of the molten bath flowing through the tundish 860 by the heat transmitted from the gas conduit 845. It should be noted that for a work supply mechanism consisting of a conveyor 846, a thread 847, a chain 848, a motor 849 and a hopper 850, the aluminum material 824 to be melted can be continuously charged to the crucible 801.

- Method to Melt and Separate Aluminum- By employing the continuous melting apparatus discussed in the foregoing in detail, the operation of melting and separating the material containing aluminum and metal having a higher melting point can be effected very efficiently and rationally. Waste metal products, such as motor vehicles, motorcycles, refrigerators electrical, etc. they are dismantled by crushing and other means, and the portion that can be used is recycled as a regenerated ingot. Among these metal products, there is a large number of parts, in which members of aluminum and iron, members of copper, etc. are integrated. These parts include many parts that are difficult to mechanically separate into respective elementary materials. Therefore, a method has been carried out to separate the elementary materials using the difference of melting points of aluminum, copper, etc. However, in the conventional method, the melting and separation operation can not be effected efficiently, and the temperature control in the melting furnace is difficult. This is the reason why aluminum and copper alloy often occurs in conventional ovens or methods, which leads to frequent failures in the separation process. Therefore, a method according to the present invention performs the melting and separation operation in the following manner. ? For example, the continuous melting apparatus as illustrated in Figures 8 and 9 is employed. It is assumed that the material is a radiator in an electric refrigerator. This is a mixed material in which the portion of aluminum fin and the portion of the copper pipe are integrated. Such material hangs by cables to receive in a melting crucible 301 and then the crucible 301 is heated by the burner 308. The melting point of the aluminum (660.4 ° C) is lower than the melting point of the copper (1084.5 ° C). Therefore, the portion of aluminum fin in the material begins to melt first. At this time, in order not to completely melt the aluminum fin portion, additional material is appropriately loaded into the crucible 301 to cause the operation to progress to reside a certain amount of the solid aluminum material in the crucible 301. A part of the heat applied by the burner 308 is consumed as the heat of fusion (94.8 Kcal / Kg) of the aluminum material, the temperature of the molten bath of aluminum in the crucible 301 is kept substantially constant at a temperature close to the melting point of the aluminum. Therefore, the temperature of the aluminum metal will never be excessively high. Thus, separation failure by causing the aluminum-copper alloy reaction to melt the portion of copper tubing in the material can be successfully avoided. A relationship between the temperature and a time in the crucible in the above embodiment is illustrated in the graph shown in Figure 20. During a certain period in the initial stage of heating, the temperature in the crucible rises sharply. After 12.3 seconds, the temperature rise decreases, and increases to 60.6 seconds, the The temperature of the molten bath is maintained substantially at the melting point. Additional material is added appropriately to maintain this condition. When the molten aluminum bath in the crucible 301 reaches the female screw hole 302. Then, the molten bath flows into the holding furnace B. As can be seen from the above discussion, the present invention achieves the following effects. (1) The fusion process can be carried out efficiently and continuously. (2) Because the apparatus is based on the crucible furnace, the installation space may be small, the investment for installation and maintenance low, and the operating cost may be low. (3) The operation to remove the pieces of metal accumulated on the surface of the molten bath in the crucible is facilitated and the operation of removing pieces of metal can be done without interrupting the continuous melting process, and the worker is not subjected to extreme heat. (4) Because the level of the molten bath in the crucible can be kept constant, the appropriate preheating zone above the meniscus of the molten bath can be defined. Although the material passes through the preheating zone, the residual deposition on the material can be removed effectively. Therefore, the reaction strong, such as the phreatic explosion is difficult to cause to allow a safe progress of the fusion operation. (5) Because the inner part of the crucible can be maintained in an atmosphere of non-oxidation, the oxidation loss can be very small. (6) Because the apparatus uses crucible furnace technologies, it can be done in a compact form and at a low cost. Because the molten bath can be received in the respective crucibles when it is in the melting furnace and when it is in the holding furnace, handling becomes easier. In addition, when exchanging the empty crucible, the device can be cooled as if it were a new device. Therefore, maintenance becomes very easy. (7) Aluminum scrap or ingot can be continuously melted by keeping the molten bath at an adequate temperature, functionality can be achieved and it is practical to allow the extraction of the molten bath as required. (8) Because the scrap and the aluminum ingot are not directly subjected to the furnace flame, the oxidation loss is very small, and the amount of hydrogen mixed in the molten bath is very small. (9) The agglomerate of native aluminum oxide due to the reaction of the molten aluminum bath and the wall material of the furnace is avoided.

Although the present invention has been illustrated and described with respect to the exemplary embodiment thereof, those skilled in the art will understand that the foregoing, as well as various other changes, omissions and additions can be made therein and the same, without departing from the spirit of the invention. spirit and scope of the present invention. Therefore, the present invention should be understood not as limiting the specific modality set out in the foregoing, but to include all possible modalities that can be modalized within a scope encompassed and the equivalents thereof with respect to the aspect set forth in the appended claims. . -

Claims (16)

1. A continuous melting apparatus for a metal of low melting point, characterized in that it comprises: a main body of a melting furnace forming a combustion chamber surrounded by a refractory lining; a crucible formed with a female screw hole in a suitable position of a body and housed in the central portion of the combustion chamber; a burner provided on a side wall portion of the main body of the melting furnace to heat the crucible in the combustion chamber; and a receptacle for receiving the molten bath flowing through the female screw hole of the crucible.

2. A continuous melting apparatus, according to claim 1, characterized in that the base of the crucible is fixed on a floor of the combustion chamber and the crucible is mounted on the base of the crucible.

3. A continuous melting apparatus, according to claim 2, characterized in that the floor portion of the combustion chamber serves as a first receptacle receptacle for accumulating the molten bath flowing outwardly through the female screw hole, and the first receptacle container communicates with a second receptacle receptacle located outside the combustion chamber.

4. A continuous melting apparatus, according to claim 3, characterized in that the second receptacle container is provided with a retention heater for heating the molten bath received therein.

5. A continuous melting apparatus, according to claim 1, characterized in that a tundish is connected to the external part of the female screw hole of the crucible and the molten bath flowing through the female screw hole is guided to the receptacle located outside the the combustion chamber by means of the trough.

6. A continuous melting apparatus, according to claim 5, characterized in that the receptacle comprises a retention furnace body forming a heating chamber surrounded by a refractory lining, a retention crucible provided in the central portion of the heating chamber , and a holding heater provided on the side wall portion of the main body of the holding furnace to heat the holding crucible.

7. A continuous melting apparatus, according to claim 5, characterized in that a plurality of receptacles are provided, and the tundish is constructed to distribute the molten bath flowing through the female nipple to the respective plurality of receptacles.

8. A continuous melting apparatus, according to claim 1, characterized in that a baffle plate is arranged with a suitable distance from the female screw hole inlet to prevent pieces of metal from flowing out of the female screw hole of the crucible .

9. A continuous melting apparatus, according to claim 1, characterized in that an open pipe extending downwardly from the female screw hole is located in the crucible to prevent pieces of metal from flowing out of the female screw hole of the crucible. . "

10. A continuous melting apparatus, according to claim 1, characterized in that an upwardly directed channel is connected in the external part of the female screw hole to prevent the pieces of metal flow out of the female screw hole of the crucible.

11. A continuous melting apparatus, according to claim 1, characterized in that a window is formed that unlocks pieces of metal in the body portion of the crucible in a different orientation position relative to the female screw hole, with the lower edge located in the level next to the female screw hole and being elongated in the width direction, and a working opening for unloading the pieces of metal is formed on the side wall portion of the main body of the melting furnace in a spatially continuous position to the unloading window of metal pieces.

12. A continuous melting apparatus, according to claim 2, characterized in that an air flow hole is formed to extend laterally in the base of the crucible Y

13. A crucible as an upwardly open refractory container comprising: a female screw hole formed through a body portion in a suitable lower position of the upper edge of the container; a locking member provided in a portion of the female screw hole and which prevents pieces of metal from flowing out of the female screw hole; and a metal pieces unloading window formed through the body portion in a different orientation position relative to the female screw hole, having a lower edge at a level close to the female screw opening, and being elongated in the width direction.

14. A crucible, according to claim 13, characterized in that the unloading window of pieces of metal is defined by a recess cut reaching the upper end thereof with respect to the upper edge of the container.

15. A crucible, according to claim 13, characterized in that a channel is integrally connected to the external part of the unloading window of pieces of metal, the channel is provided with an upward inclination from the lower edge of the unloading window of metal. pieces of metal.

16. A method to melt and separate aluminum from the material containing aluminum and another metal that has a point melting apparatus, using a continuous melting apparatus, according to claim 1, characterized in that a suitable amount of the material is additionally charged to the crucible at a suitable time to keep the non-molten aluminum in a molten aluminum bath in the crucible.