US2194453A - Method and apparatus for handling molten metal - Google Patents

Description

March 19, 1946. J. D. BURBY METHOD AND APPARATUS FOR HANDLING MOLTEN MET AL Filed Oct. 19, 1 958 Ill-III lllllllll INVENTOR J- ES Patented Mar. 19 1940 I METHOD AND APPARATUS FOR HANDLENG MOLTEN METAL James D. Barby; Hastings onfiudson, N. L, as-

signor to Anaconda Wire & able Company, New York, N. Y., a corporation of Delaware Application Dctober 19, 1938, Serial No. 235,7?2

Claims.

This invention relates to the transference of molten metal from one chamber to another, and more particularly relates to a method and apparatus for filling the cylinder of a lead press from a melting pot.

Recent developments and investigation have indicated that the extrusion of a satisfactory lead sheath such as is commonly applied to the'larger sizes of electric cables 'is to a great extent, dependent upon proper handling of the lead durin processing. Formerly it was the usual procedure to employ a portable tube which would serve as a conduit between the melting pot and the cylinder of the lead press. When the lead was handled in this manner it was permitted to drop through the atmosphere for a distance which corresponded to the height from the top of the cylinder to the top of the charge. 1 This procedure resulted in considerable degree of splashing which had two major disadvantages; first, the obvioushazard of highly heated'metal to the workmen and second, the fact that small globules of air were introduced into the charge because of the extreme agitation of the lead during pouring. Recently this process has been improved by extending the portable tube in such .a manner that it extends into the cylinder of the press and rests upon the top of the previous charge. Such an arrangement tends to greatly reduce the splashing which attends the pouring of the metal but even this refinement is not wholly satisfactory inasmuch as any impurities or sludge which may be found in the melting pot are carried to the bottom of the molten charge and therefore there is less chance that they will find their way to the surface where they may be skimmed'ofl than if the portable tubehad not extended through the charge.

Accordingly, it is the chief object of this invention to provide a method and apparatus which will avoid splashing and disturbance during the pouring of the metal and. at the same time will introduce the most recently poured metal at a point which is generally close to the surface of the charge. Another object of this invention is to so handle the molten metal that any dross. oxide or impurities which may be included will be confined to the top. of the charge where they may be removed by sldmming after pouring has been completed. A still further object of this invention is to provide a safer and more rapid method for the handling of molten metals.

Other objects of the present invention will be apparent from the following description when read in connection with the accompanying drawing which is an elevational view of a melting pot and lead press cylinder, with suitable means for the transference of molten metal, certain parts having been broken away for purposes of explanation.

Referring to this drawing, a charge of molten lead I is shown within a melting pot 2. (Means for heating the melting pot have not been includedinthe drawing since any one of several methods is entirely suitable for the purpose.) 4 from the melting pot is closed by a suitable valve 5 actuated through the rod 8, by any suitable handwheel or motor which is not shown.

The lead press is indicated as a die block I, a ram 8 and a container 9. In the usual course of i6 operation the container is filled with molten lead which is then allowed to'stand for a time sufilcient to permit it to solidify to a plastic state in. which the lead, ,while not fluid, is still more readily extruded than at normal temperature. When the correct temperature has been reached the ram is brought down upon the charge under high pressure and the lead is thus forced through the die block and extruded, generally as a cylinder surrounding an insulated cable. Of course it is not possible to extrude all the lead since the ram cannot enter the constricted die block and therefore the ram is usually withdrawn while there is a slight amount of solidified lead in the bottom of the cylinder. It is this stage of the operation that is indicated in the accompanying drawing and at this point lead is again admitted into the cylinder by opening the valve 5 and the cycle is repeated. 7

In the apparatus shown a fixed outlet tube It is attached directly to the outlet 4 through a suitable connection, in this case indicated as a threaded joint. The extreme end of the outlet pipe terminatesin a swivel joint H to which is connected a hinged filling tube l2. That portion of the filling tube which is designed to enter the cylinder of the press is preferably formed on the circumference of a circle whose radius is slightly less than the distance from the swiveled joint II to the more distant side of the cylinder, the distance being measured along a line passing through the center of the joint and normal to the wall of the cylinder.

when the filling operation is commenced the only lead in the cylinder is the solid metal (I3) remaining from the previous charge. The filling tube is so placed that a slight distance between the lead and the tube is provided for the escape of the molten metal and the valve -5- is then opened and the molten metal rises in the cylin- The outlet 1 fact that the system is completely sealed, it may be, noted that there are always some impurities carried into the cylinder from the melting pot and it is one of the purposes of this invention to prevent this dross from becoming entrapped in the charge. Because of the high specific grav ity of lead almost all impurities are lighter than the metal and therefore tend to rise through the liquid, however the lead in the cylinder is constantly cooling and if the dross has to travel a considerable distance, the impurities may be entrapped within the solidified metal. This objection is overcome in the present instance by raising the filling tube within the cylinder as the lead rises within the chamber. It is desirable to place some distinctive mark it upon the lower end of the filling tube approximately 2" front. the exit end and the operator may then raise the tube as lead is admitted keeping the mark at the surface of the rising metal. When this is done there will not be any splashing since the mouth of the tube is, always kept beneath the surface of the metal and, on the other hand,,any impurities which are carried into the cylinder will be discharged at a point close to the surface so that there will be but a short distance to travel. When the cylinder is completely filled, it is allowed to overflow slightly so that the dross and impurities may be skimmed off, the filling tube being withdrawn constantly during this procedure as indicated by the dotted outline l5, which is the position of the movable tube when the lead has been filled to the point indicated as A. When the cylinder has been completely filled and no more lead is to be admitted, the filling tube maybe swung to the position indicated as It where it will be out of the way until again required. It has been found in practice that a certain amount of lead is entrapped in the filling tube when it is left .in the position indicated as l6 and this metal will of course solidify upon standing. This is not a serious difficulty since the temperature of the lead within the melting pot is sufficiently high to melt without the frozen metal when the. valve is again opened. In some cases, however, it may be desirable to jacket a portion of the filling tube with a heating medium to maintain the lead in a liquid state. Such heating means may be of any known design.

either gas or electric, and the specification is accordingly not encumbered with this detail.

In the accompanying drawing many mechanical details of the press and melting pot, together with the structure necessary to support and actuate the mechanism have been omitted as they tend to obscure the more important features of the invention.

What I claim is:

1. Apparatus. for handling metal comprising a reservoir containing a supply of a chamber into which the metal is to ,be introduced and means for transferring the metal from said reservoir to said chamber, said means comprising 'a curved pipe, pivoted at oneextremity so that it may be introduced or withdrawn from the chamber without exposing the molten metal to the atmosphere between said reservoir .and the exit end of said pipe, the curvature of said pipe coinciding with the circumference of a circle drawn with the pivot point of said pipe as a center. v

2. In a systemfor the handling of liquids, a storage chamber and a working chamber between which fluids are to be transferred and means for transferring said fluids comprising a tube pivotally attached to said storage chamber and open at the opposite extremity, a portion of said tube being curved so that it may be introduced into or withdrawn from said working chamber by rotation about the point of pivotal attachment, the curve of said tube coinciding with the circumference of a circle of which the point of pivotal attachment is the center.

3. Apparatus for'handling. molten metal comprising a storage chamber and a working chamber between which the molten metal is to be transferred, means for transferring molten metal molten metal,

comprising a pivotally mounted tube in communication with said storage chamber at one extremity and open at the opposite end, said tube being curved so that it may be introduced into or withdrawn from said working chamber by rotation about the point of pivotal attachment, the curve of said tube coinciding with the circumference of 'a circle of which the point of pivotal attachment is the center.

4. The apparatus of claim 1 in which the curved pipe is provided with means for melting metal which may have solidified within it.

5. The system of claim 2 in which the tube is provided with means for melting solidified metal within the tube.

JAMES D. BURBY.

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