US3137903A - Molten metal feeding tube for metal casting machines - Google Patents

Description

June 23, 1964 MQRTQN 3,137,903

MOLTEN METAL FEEDING TUBE FOR METAL CASTING MACHINES Filed. Feb. 13, 1961 2 Sheets-Sheet 1 IN V EN TOR.

616M 14 MOFfO/V June 23, 1964 MORTON 3,137,903

MOLTEIN METAL FEEDING TUBE FOR METAL CASTING MACHINES Filed Feb. 15. 1961 2 Sheets-Sheet 2 INVEN TOR.

Git M16 MOET 0 BY F" M (i Mow/97v 6. 7697/86 United States Patent 3,137,963 MGLTEN METAL FEEDENG TUBE FOR METAL CASTING MACHINES Glenn R. Morton, 7025 Sarpy Ave., Omaha, Nebr. Filed Feb. 13, 1961, Ser. No. 88,873 8 Claims. (Cl. 22-68) This invention relates to material feeding tubes for casting machines and especially to a molten metal supply tube for metal casting devices.

Metal casting is an old art. However, modern times require highly efiicient machines that are at least semiautomatic. Electrically controlled vacuum type machines have solved many problems present in volume casting. However, much trouble is still experienced in the metal feeding tube or conduit that passes the molten material into the shot cylinder or into the mold cavity. Firstly, the molten metal between intermittent supply flows, tends to solidify onto the walls of the feeding tube. Secondly, the feeding tube transfers objectionable heat to the shot cylinder and its ram piston. Thirdly, and perhaps more important, the molten mass tends to stratify both as to composition and temperature, thereby interfering with the successful and proper filling of the mold cavity.

Therefore, one of the principal objects of my invention is to provide a molten metal feeding tube that prevents the molten material from solidifying at the communicating orifice of the shot cylinder or well.

A further object of this invention is to provide a molten material feeding tube that transfers very little heat from the furnace to the shot cylinder or mold.

A still further object of this invention is to provide a molten material feeding tube that materially aids in the successful and proper filling of the mold cavity.

A still further object of this invention is to provide a molten material feeding tube that eliminates the solidifying of the molten material at the communicating orifice of the shot well or cylinder thereby not only keeping the orifice open, but also permitting the use of a cooling means for the shot well or cylinder and its piston. A still further object of this invention is to provide a molten material feeding tube that greatly reduces the initial impact shock of the molten material intermittently passing therethrough.

More specifically, the object of my invention is to provide an insulated molten material feeding tube that imparts to its discharging molten material a spiral impetus.

A still further object of my invention is to provide a molten material feeding tube that is economical in manufacture and durable in use.

These and other objects will be apparent to those skilled in the art.

My invention consists in the construction, arrangements, and combination, of the various parts of the device, whereby the objects contemplated are attained as hereinafter more fully set forth, specifically pointed out in my claims, and illustrated in the accompanying drawings, in which:

FIG. 1 is a longitudinal sectional view, taken on line 11, FIG. 2, of my molten metal feeding tube means detachably secured to a shot cylinder;

FIG. 2 is a sectional view of my device taken from line 22 of FIG. 1, and more fully illustrates its construction;

FIG. 3 is a sectional view of my feeding tube taken from line 33 of FIG. 1;

FIG. 4 is a longitudinal sectional view of a modified form of structure of my material feeding tube;

FIG. 5 is a cross-sectional view of the upper portion of the feeding tube taken on line 55 of FIG. 4, and

FIG. 6 is a plan view of the feeding tube taken from line 66 of FIG. 4.

3,137,903 Patented June 23, 1964 As hereinbefore indicated, my feeding tube is particularly adapted to modern casting machines such as described in my co-pending application on 2. Vacuum Casting Machine filed November 4, 1957, and bearing Serial Number 694,315, now Patent No. 3,121,926. In most such machines there is a shot cylinder and ram piston for injecting the molten mass into the die cavity. A material supply tube leads from the furnace having the molten material vat to the inside of the shot cylinder forward of its piston. Mechanical means may be employed to draw or force the molten material through the feeding tube. However, with casting machines of the vacuum type, the molten material is sucked through the feeding tube. In fact, with some materials, a vacuum machine may dispense entirely with the shot cylinder and connect the feeding tube direct to the mold. In the drawings I show my material feeding tube having its upper end communicating with the inside of a shot cylinder or well 10 and its lower end portion extending into the molten casting material 11 of the furnace. The numeral 12 designates the entrance orifice extending through the wall of the shot cylinder. This passageway is tapered as shown in FIG. 1, i.e., its diameter increases as it extends outwardly through the wall of the cylinder. The numeral 13 generally designates the outer cylindrical wall of my feeding tube. The major portion of the length of this tube 13 extends downwardly and laterally from the shot cylinder 10 with its lower end portion extending into the molten material 11 as shown in FIG. 1. The upper end of this tube housing 13 is adjacent to the opening 12 in the bottom portion of the shot cylinder 11). I will first describe the specific structure of the feeding tube shown in FIGS. 1, 2 and 3. The numeral 15 designates a simple insulation inside the tube housing 13 and which, in fact, protrudes beyond the upper end of the tube housing 13 as shown in FIG. 1. Any suitable insulation material that would not be affected by the molten casting material may be used, such as a composition of aluminum and silica or the like. Irnbedded in the upper end of this insulation and in the upper end of the tube housing 13 is a nozzle generally designated by the numeral 16. This nozzle 16 has a discharge opening or orifice 17 and a circular chamber 19 communicating with and directly back of the opening 17. This circular compartment 19 is concentric with the opening 17 and has a diameter substantially greater than that of the diameter of the opening 17. This nozzle 16 has its outer reduced end protruding beyond the open top end of the tube 13, but its periphery is completely embraced by insulation 15. That part of the insulation that protrudes beyond the open end of the cylindrical housing 13 tapers inwardly as it extends forwardly in order to properly engage and conform to the hole 12 of the shot cylinder 10. The numeral 2t designates a lug on the under upper end portion of the cylindrical housing 13. The numeral 21 designates an ordinary C-clamp having its cap screw 22 engaging the other side of the cylinder 10 and its lower end detachably hooked over the lug 20. By this arrangement, the material feeding tube unit is detachably secured to the shot cylinder. A gasket 23 may be used in the shot cylinder hole 12. Obviously, the metallic cylinder 13 does not directly contact the shot cylinder 10. The insulation 15 has a longitudinal bore 25 decreasing in diameter as it extends upwardly. The upper end of this bore 25 communicates with the outer area of the compartment 19 at a tangent thereto as shown in FIG. 3. The nozzle opening 17 extends from a central part of the chamber 19 along an axis through the opening 12 into the shot cylinder. Thus, the outer area of the compartment 19 which communicates with the bore 25' is offset from the axis through the opening 12. By this tangential angle of the bore 25 relative to the compartment 19, molten material will enter the compartment 19 at an angle, engage the circular wall of the compartment 19, which will cause the molten material to rotate and spiral upwardly through the nozzle opening 17. This rotating or spiraling of the molten mass will obviously solve several problems. Firstly, it will automatically self-clean the upper end portion of the feeding tube. Secondly, the whirling action of the molten material will keep it successfully mixed against stratification as to composition and/or temperatures. To further promote the whirling and discharging of the molten material from the feeding tube, I have provided a dome 26 to extend from the main mass of insulation into the central area of the compartment 19 of the nozzle. This dome 26 is spaced from and directly back of the nozzle opening 17 The point of entrance of the bore 25 into the compartment 19 is obviously at one side of this dome 26. Even if in one cycle of a casting machine some molten metal would congeal within the discharge nozzle, the next cycle of whirling molten metal would eliminate such previously congealed metal. However, substantially all of the molten metal will either run into the shot cylinder or back into the furnace. This return of the molten metal to the furnace is encouraged by the bore 25 increasing in diameter as it extends downwardly. The insulation of my material feeding tube also prevents rapid chilling. Therefore, the molten material is maintained in suitable liquid state during the use of the casting machine. Thus, it is possible and practical to feed molten metal from the center of the bath to the shot well with no thought of solidification, even when starting from cold. It takes about one hour for the thermal tube to come up to heat on the inside, but it need never be removed once it is installed as the highly insulating material is not affected by the molten metal. Ordinarily the metal travels up the tube slowly and at a constant speed, but with the orifice up to the top out of the bath, the metal travels at a terrific speed until it hits the restricted orifice and the sudden stopping of the metal is like a hammer blow. This would obviously ruin the insulation, but by tapering this hole from large at the bottom to small at the top, this impact is reduced to the degree that this material will stand up. This also explains to a degree why the bath level does not affect the size of the shot since the time element for the metal to reach the orifice is so short it is negligible. Furthermore, by my construction the metal cylindrical housing 13 will not unduly transfer heat to the shot cylinder. This makes possible the auxiliary cooling of the shot cylinder if desired. If desired, the outside of the cylindrical housing 13 may be insulated.

As before indicated, FIGS. 4, 5, and 6 show a modified structure and which has the advantage of better drain back into the furnace. The modified structure also has the outer tube housing 13, the insulation 15 and the passageway 25, decreasing in diameter as it extends upwardly. It, however, does not have the ring 16. Instead I imbed in the upper end of the tube 13 and in the insulation a cone-shaped ceramic insert nozzle 30. The upper open end 31 of this nozzle 30 discharges the molten material into the shot cylinder or mold as shown in FIG. 4. The open base of the cone-shaped nozzle insert communicates with a cavity 32. The upper end of the passageway 25 communicates with, but at a tangent to, the cavity 32 as shown in FIG. and FIG. 6. This arrangement of parts gives a whirling or spinning action to the molten material as shown by broken lines in FIG. 6. Also, by the structure shown in FIG. 4, the molten material in the feeding tube will not be trapped, but will drain properly back into the furnace. The ceramic cone-shaped nozzle is excellent in resisting high temperatures and is of long life. The numeral 35 designates a metal tip or ring in the tapered opening of the shot cylinder to protect the ceramic insert 30.

Some changes may be made in the construction and arrangement of my molten metal feeding tube for metal casting machines without departing from the real spirit i and purpose of my invention, and it is my intention to cover by my claims, any modified forms of structure or use of mechanical equivalents which may be reasonably included within their scope.

I claim:

1. A molten metal feeding tube for use in feeding molten metal from a molten metal supply reservoir to a shot cylinder of a molding machine having an opening in one wall thereof, said molten metal feeding tube comprising an axially elongated outer tubular wall, insulating means extending through the entire inside of said outer tubular wall, means providing a chamber in said insulating means at the end of said outer tubular wall adjacent said shot cylinder, said chamber being provided with a smaller discharge orifice leading from a central part of said chamber along an axis through said opening into said shot cylinder, and a passage in said insulating means opening into said reservoir and extending along the feeding tube and having a portion entering said chamber in an area ofiset from said axis through said opening, said passage portion having a longitudinal axis which intersects a chamber wall and is spaced from said axis extending through said opening to cushion the impact of the charge of metal drawn through and discharged from the feeding tube and to maintain the homogeneous composition and temperature of the charge.

2. A molten metal feeding tube for use in feeding molten metal from a molten metal supply reservoir to a shot cylinder of a molding machine having an opening in one wall thereof, said molten metal feeding tube comprising an axially elongated outer tubular wall, insulating means extending through the entire inside of said outer tubular wall, a nozzle member embedded in said insulating means at the end of said outer tubular wall adjacent said shot cylinder and providing a chamber and having a discharge orifice smaller than said chamber leading from a central part of said chamber along an axis through said opening into said shot cylinder, and a passage in said insulating means opening into said reservoir and extending along the feeding tube and having a portion entering said chamber in an area offset from said axis through said opening, said passage portion having a longitudinal axis which intersects said chamber wall and is spaced from said axis extending through said opening to cushion the impact of the charge of metal drawn through and discharged from the feeding tube and to maintain the homogeneous composition and temperature of the charge.

3. A molten metal feeding tube as set forth in claim 2 wherein said nozzle member is ceramic.

4. A molten metal feeding tube as set forth in claim 2 wherein said outer tubular wall is maintained in spaced relation to said shot cylinder by said insulating means.

5. A molten metal feeding tube as set forth in claim 2 wherein both said outer tubular wall and said nozzle member are maintained in spaced relation to said shot cylinder by said insulating means.

6. A molten metal feeding tube as set forth in claim 2 additionally including a dome-like projection in said chamber on the side thereof opposite said discharge orifice and projecting along said axis toward said discharge orifice to induce the movement toward said discharge orifice of the molten metal entering said chamber.

7. A molten metal feeding tube as set forth in claim 2 wherein said passage is of diminishing cross sectional size from said reservoir to said chamber.

8. A molten metal feeding tube for use in feeding molten metal from a molten metal supply reservoir to a shot cylinder of a molding machine having an opening in one wall thereof, said molten metal feeding tube comprising an axially elongated outer tubular Wall, insulating means extending through the entire inside of said outer tubular wall, means providing a chamber in said insulating means at the end of said outer tubular wall adjacent said shot cylinder, said chamber having a cylindrical inner wall surface, said chamber being provided with a smaller discharge orifice leading from a central part of said chamber along an am's through said opening into said shot cylinder, and a passage in said insulating means opening into said reservoir and extending along the feeding tube and having a portion entering said chamber in an area offset from said axis through said opening, said passage portion having a longitudinal axis which intersects said cylindrical inner wall surface and is spaced from said axis extending through said opening to cause the charge of metal to engage the cylindrical wall and spiral outwardly of said chambers through said opening in said shot cylinder wall and thereby to cushion the impact of the charge of metal drawn through and discharged from the feeding tube and to maintain the homogeneous composition and temperature of the charge.

References Cited in the file of this patent UNITED STATES PATENTS 1,732,515 Hunter Oct. 22, 1929 1,978,765 Sargent Oct. 30, 1934 2,708,298 Beckes May 17, 1955 2,817,884 Ring Dec. 31, 1957 2,856,656 Ring Oct. 21, 1958 2,977,649 Morton Apr. 4, 1961

Claims (1)

1. A MOLTEN METAL FEEDING TUBE FOR USE IN FEEDING MOLTEN METAL FROM A MOLTEN METAL SUPPLY RESERVOIR TO A SHOT CYLINDER OF A MOLDING MACHINE HAVING AN OPENING IN ONE WALL THEREOF, SAID MOLTEN METAL FEEDING TUBE COMPRISING AN AXIALLY ELONGATED OUTER TUBULAR WALL, INSULATING MEANS EXTENDING THROUGH THE ENTIRE INSIDE OF SAID OUTER TUBULAR WALL, MEANS PROVIDING A CHAMBER IN SAID INSULATING MEANS AT THE END OF SAID OUTER TUBULAR WALL ADJACENT SAID SHOT CYLINDER, SAID CHAMBER BEING PROVIDED WITH A SMALLER DISCHARGE ORIFICE LEADING FROM A CENTRAL PART OF SAID CHAMBER ALONG AN AXIS THROUGH SAID OPENING INTO SAID SHOT CYLINDER, AND A PASSAGE IN SAID INSULATING MEANS OPENING INTO SAID RESERVOIR AND EXTENDING ALONG THE FEEDING TUBE AND HAVING A PORTION ENTERING SAID CHAMBER IN AN AREA OFFSET FROM SAID AXIS THROUGH SAID OPENING, SAID PASSAGE PORTION HAVING A LONGITUDINAL AXIS WHICH INTERSECTS A CHAMBER WALL AND IS SPACED FROM SAID AXIS EXTENDING THROUGH SAID OPENING TO CUSHION THE IMPACT OF THE CHARGE OF METAL DRAWN THROUGH AND DISCHARGED FROM THE FEEDING TUBE AND TO MAINTAIN THE HOMOGENOUS COMPOSITION AND TEMPERATURE OF THE CHARGE.

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