US2243031A

US2243031A - Method and apparatus for applying metallic sheaths to cables

Info

Publication number: US2243031A
Application number: US273155A
Authority: US
Inventors: Leigh E Fogg
Original assignee: KENNECOTT WIRE AND CABLE COMPA
Current assignee: KENNECOTT WIRE AND CABLE Co; KENNECOTT WIRE AND CABLE COMPA
Priority date: 1939-05-11
Filing date: 1939-05-11
Publication date: 1941-05-20
Anticipated expiration: 1958-05-20

Description

May 20, 1941. 5, F066 2,243,031

METHOD AND APPARATUS FOR APPLYING METALLIC SHEATHS TO CABLES Filed May 11, 1939 2 Sheets-Sheet 1 L. E. FOGG May 20, 1941.

METHOD AND APPARATUS FOR APPLYING METALLIC SHEATHS T0 CABLES Filed May 11, 1939 2 Sheets-Sheet 2 p 3 W 9 @M W f w Patented May 20, 1941 METHOD AND APPARATUS FOR. APPLYING DIETALLIC SHEATHS TO CABLES Leigh E. Folg, East Providence, a. 1., assignor to Kennecott wire and Cable Company, Phillipsdale, R. 1., a corporation Application May 11, 1939, Serial No. 273,155

8 Claims. (Cl. 207-4) This invention relates to improvements in meth- I ods and apparatus for applying metallic sheaths to cables.

Heretofore in the art of applying metallic sheaths to electric cables, which sheaths ordinarily are of lead or lead alloy, considerable trouble has arisen from e presence of oxide and other foreign matter pr impurities being present in the lead when it is extruded from the press into the form of a slteath about the cable and thus causing defects. One of the most serious reasons for the foreign matter causing trouble results from the" fact that the sheathing press or lead press, as it is called, isof such limited capacity that it is unable to contain a sufiiciently large charge of lead to extrude a sheath for a full length of cable. Therefore, as the sheathing press has to be recharged with molten lead one or more times'in order to form a complete length of sheath on a single length of cab1e,,there may be one or more welds or locations along the sheath wherethe successive lead charges join in the sheath, and it is particularly at these locations that the most serious defects due to impurities occur. Although many eiforts have been made to eliminate the impurities from the lead in the press'and thus avoid the difllculty of inferior and defective sheaths, this has not heretofore been satisfactorily accomplished.

I have found that by centrifugally treating the metal in molten condition before putting it in the sheathing press, that the impurities can besubstantially entirely eliminated from the metal, so that a perfect sheath can be formed over a full length of cable, even at the locations where the successive charges of lead merge together.

One object of this invention, therefore, is to provide an improved method of substantially eliminating impurities from the metal in the sheathing press in order to make the sheath free from defects.

Another object of this invention is to provide improved apparatus for carrying out the foregoing method.

With the above and other objects in view, as will appear to those skilled in the art from the present disclosure, this invention includes all features in the said disclosure which are novel over the prior art.

In the accompanying drawings forming part of the present disclosure, in which one way of carrying out the invention is shown for illustrative purposes:

Fig. 1 is a schematic vertical sectional v ew illustratlng one embodiment of an apparatus for carrying out the invention;

Fig. 2 is a cross sectional Fig. 1;

Fig. 3 is a cross sectional view on line 3-3 of Fig. l; and

Fig. 4 is a cross sectional view on line 4-4 of Fig. 1.

In the description and claims, the various parts and steps are identified by specific names for convenience, but they are intended to be as generic in their application as the prior art will permit.

Referring to the drawings showing the particular form of the invention chosen for illustration, the apparatus illustrated, in the main, comprises a melting furnace I, a centrifugal separator Ii, a supply or storage kettle or chamber view on line 2-2 of or tank l2, and a sheathing press It.

The melting furnace ll may'be constructed in any suitable way, and is illustrated as having a suitable burner ll which can receive gas or other suitable heating medium through a pipe l8. Airinlet openings I 9 in the casing Ii provide an ample supply of air to the burner I1, and exit openings 20 provide an adequate exit for the burned gases from the burner, If desired, the melting furnace I. may be, provided with a suitable cover lid, and a pipe lob for introduction of steam or hydrogen or other suitable fluid medium into the melting chamber l4 or for providing a vacuum therein, to maintain a non-oxidizing or reducing atmosphere in contact. with the metal being melted in the melting chamber l4 or otherwise minimize or preclude oxidation.

The centrifugal separator ll includes a lower fixed bearing 2| on which is rotatably mounted a centrifugal bowl or cylinder 22, which bowl 22 has a shaft 23 rotatably mounted in a fixed upper bearing 24 forming part of a spider 25 having its rim portions 26 and 21 respectively fitting within, and resting upon the upper edge of, the

upper rim portion 28 of a storage or circulating pot has the parts 30, 3|, 32 and part of coupling 33 1 carried thereon, so that when the cover 34 is swung down to the position shown and locked by the bolt 31 and 'nut 38, the parts of the coupling 33 are in driving engagement with one another, so that the motor 30 can rotate the centrifugal bowl 22. A flexible or other suitable pipe or tube 39 leads through the cover or other suitable part of the tank 29 to provide for the introduction of steam or hydrogen or other suitable fluid medium or to provide a vacuum in the tank, to maintain a non-oxidizing or reducing atmosphere in contact with the metal being purified by the centrifugal separator or otherwise preclude or mini- 3 mize oxidation. The tank 29, at its lower end carries the lower bearing 2| of the centrifugal 1 separator The sheathing press or lead press l3 can be of any suitable or usual form, and in the form shown includes a cylinder 48 and a power-actuated piston or ram 4| adapted to slidingly lit the inner cylindrical surface of the cylinder 49. The cable I 42 to be sheathed, is adapted to extend completely press |3 including the sheathing die at the far side of the press, in a well-known in the art.

through the lower part of the sheathing manner that is usual and A pipe 44 leads from the bottom of the melting |4 through a control valve 45 to a T 46,

and thence in one direction downwardly through a drain valve 41 and a drain pipe 48, and in the opposite direction upwardly through a pipe sec- 'tion 49 to the interior passage 58 of the bearing 2| and into the centrifugal cylinder or bowl 22. 1 One or more inlet or ingress ports or openings 5| 1 provide ingress into the passage 59 leading to the centrifugal bowl 22, from the interior 52 of the storage or circulation tank or kettle 29. The ingress openings 5| can be controlledbyanysuitable valve means such, for example, as the rotary valve-sleeve 53 having an arm 54 provided with a slot 55 engaged by the end of a rod 56 slidably extending through a lead-tight packing-connection 51 and carrying an operating knob 58. One

ports 59 are v or more egress or outlet openings or provided at the upper end of the centrifugal bowl with a channel leading from the outlet openings 59 of the centrifugal separator, thus entirely eliminating the use of any storage or re-circulating tank. Or, a supply or storage tank or kettle for molten metal could be in the form of a separate sealed kettle.

When a charge of metal has been melted in the melting pot I4 and brought to a desired temperature, the drain valve 41 is closed, valve-sleeve 53 is rotated by the knob 58 to close the ports 5|, and control valve 45 is opened to permit the Y molten metal to flow from pot l4 through the pipes 44 and 49 into the interior 50 of bearing 22. The egress port or ports will have a suitably smaller cross-sectional area than the ingress port or ports to ensure that V der remains fully charged with both lead and the separated impurities.

A pipe 60 leads from the interior 52 of the tank 29 through a control valve 6| and through the passage 62 into the interior chamber 63 of the cylinder of the sheathing press |3.

Although heat insulation has only been shown as surrounding the melting pot, it will be appreciated that any other parts of the apparatus that it is found preferable to have surrounded with heat insulation material can be readily so provided to aid in retaining the metal in molten condition at all locations from the melting pot to the sheathingpress. Also, electrical or other suitable heating means may desired, to aid in maintaining the metal in molten condition.

Instead of having the storage tank 29 surrounding the centrifugal separator II, a storage tank or kettle could be arranged away from the centrifugal separator with suitable piping leadthe centrifugal cylinbe provided where ing from the outlet openings 59 of the separator 2| and into the centrifugal bowl or cylinder 22, which when adequately full, is set into operation by starting the motor 25. The centrifugal force created by the rotating metal in the rotating centrifugal cylinder 22 causes the impuri-' ties, which are lighter than the molten metal, to be forced by the heavier metal to move inward toward the center of the rotating mass of molten metal. As the mass of molten metal speeds up, it rises inthe centrifugal cylinder and starts passing out of the egress ports 59. The molten metal which passes out through the egress ports 59 drops down into the interior'of the tank 29 until the molten metal in the tank 29 rises to such a height as is desired, whereupon the control valve is closed and the knob 58 is actuated to rotate the valve-sleeve 53 to open the ingress ports 5|, whereupon molten metal flows by gravity through the ingress ports 5| and upwardly through the center opening to constantly replenish the supply of metal that is being centrifugally purified within the cylinder 22 and thrown out through the egress ports 59. The egress ports 59 are of suitably less total area than the total area of the ingress ports 5| so that a suflicient amount of molten metal can enter the centrifugal cylinder to maintain the latter adequately full.

Thus, as the centrifugal cylinder 22 continues to rotate, the metal in the vicinity of the cylinder wall moves up and flows out of the egress ports 59, and other metal flows in the ingress ports 5|, thus bringing about a circulation of the body of molten metal in the tank 29 to thus subject this mass of metal to repeated purification. If desired, at any time, the centrifugal separator can have its rotation stopped, the valve-sleeve 53 can be closed, and the drain valve 41 can be opened to drain out the lead within the cylinder 22 with,

the impurities contained therein.

Upon the control valve 6| being opened byturning the handle 61, purified lead can flow from the tank 29 through the pipe 69 into the interior 63 of the sheathing press l3, the filling of the chamber 63 being facilitated by raising the ram 4| which tends to cause a vacuum. If undercut groove means 86 is avoided in the underface of the ram 4|, it will aid in causing the residual lead adjacent the ram to be drawn up with the ram, thus leaving the inner end of the passage 62 unobstructed. The control valve 6| is then closed by properly turning its handle When the ram 4| is caused to move down under power to press the plastic metal in the chamber 63, plastic lead is formed into a solid metal sheath 64 surrounding the cable 42, as the cable moves from left to right as indicated by the arrow in Fig. 1.

When the ram reaches the end of its downward movement, it is caused by the operator to be actuated to be retracted upward again to draw in a renewed supply of molten metal. The

ram isthen again caused to move downward to force molten metal to continue to form another section of sheath about the cable 42. The operation is repeated as often as necessary to completely sheath a complete length of cable.

Thus, it will be seen that by interposing a centrifugal separator between a melting chamber and a sheathing press, whether or not any storage tank is employed in connection with the centrifugal separator, all metal fed to the sheathing press will have been centrifugally purified so as to be substantially free of oxides or other impurities, and thus permit of applying metal sheaths to cables with the metal sheaths substantially perfect and free from oxides or other impurities, throughout all portions of the sheath.

The invention may be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of the invention, and the present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

I claim: 1. The method of applying lead-base metallic sheaths to electric cables, comprising: centrifugally removing impurities from lead-base sheath metal while in a molten condition and ing press for forming lead-base sheath metal into a sheath on a cable; a centrifugal separator constructed and arranged to retain a substantial body of molten lead-base sheath metal and-centrifugally remove impurities from the said molten metal by causing the impurities to travel to the interior portion of the body of molten metal; a tank for receiving said centrifugally purified lead-base sheath metal from said centrifugal separator; and means for conveying said centrifugally purified lead-base sheath metal from said tank into said sheathing press. I

3. Apparatus for applying metallic sheaths to cables, including: a sheathing press for forming sheath metal into a sheath on a cable; a centrifugal separator for centrifugally removing impurities from sheath metal while in a molten condition; a tank adapted to recirculate molten sheath metal through said centrifugal separator; and means for conveying said centrifugally purified sheath metal into said sheathing press.

4. Apparatus for applying metallic sheaths to cables, including: a sheathing press for forming sheath metal into a sheath on a cable; a centrifugal separator for centrifugally removing impurities from sheath metal while in a molten condition; a tank surrounding said centrifugal separator and adapted to recirculate molten sheath metal through said centrifugal separator;

and means for conveying said centrifugally purl fied sheath metal into said sheathing press.

5. Apparatus for applying metallic sheaths to cables, including: a sheathing press for forming sheath metal into a sheath on a cable; a centrifugal separator for centrifugally removing impurities from sheath metal while in a molten condition; drain means communicating with the lower end of said centrifugal separator; and means for conveying said centrifugally purified sheath metal into said sheathing press.

6. Apparatus for applying metallic sheaths to cables, including: a melting chamber for sheath metal; asheathing press for forming sheath metal into a sheath on a cable; and a centrifugal separator for centrifugally removing impurities from sheath metal while in a molten condition having an inlet end communicating with said melting chamber for receiving molten sheath metal therefrom and an outlet end communicating with said sheathing press for conveying said centrifugally purified sheath metal into said sheathing press.

7. Apparatus for applying lead-base metallic sheaths to electric cables, including: a centrifugal separator constructed and arranged to retain a substantial body of molten lead-base sheath metal and centrifugally remove impurities from the said molten metal by causing the impurities to travel to the interior portion of the body of molten metal, and to cause purified molten metal to be removed from the said centrifugal separator from the exterior portion of the body of molten metal without carrying with it any of the impurities which had been caused to travel to the interior portion of the body of molten metal.

8. Apparatus for applying lead-base metallic sheaths to electric cables, including: a centrif- 1188.1- separator constructed and arranged to retain a substantial body of molten lead-base sheath metal and centrifugally remove impurities from the said molten metal by causing the impurities to travel to the interior portion of the body of molten metal, and to cause purified molten metal to be removed from the said centrifugal separator from the exterior portion of the body of molten metal without carrying with it any of the impurities which had been'caused to travel to the interior portion of the body of molten metal, said centrifugal separator having an inner inlet and an outer outlet for the molten metal. v

IEIGH E. FOGG.