US2228766A - Apparatus for saturating the fibrous covering of wire - Google Patents

Description

Jan. 14, 1941. T. s. JOHNSON Erm.

APPARATUS FOR SATURATING TH FIBROS COVERING OF WIRE Filed Feb. 23. 1959 Jam 14, 1941- T. s. JoHNsoN ITAL 2,228,766

APPARATUS FOR STURATIG THE FIBROUS yCOVERING"OFWIRE Filed Feb. 23

. 1939 .2 Smets-'sneer 2 bhw SSH lvl MN Patented Jan. 1,4, 1941` APPARATUS FOR sA'rUnA'rlNG 'rnE minous covnarNG or wma Thor s. Johnson, Irvington, and John w. Olson,

Hastings on Hudson,

N., Y.. assigner: to

Anaconda Wire 8p Cable Company, New York, N. Y., a corporation of Delaware Application February 23, 1939, Serial No. 257,894

1 Claim.

Our invention relates to an apparatus whereby the fibrous coverings of eelctric conductors, such as wires or cables, may be saturated with molten compounds in a continuous manner.

Certain types of wire usedfor electric conductors are covered with' an insulating covering consisting of a fibrous material, such as paper impregnated with a bituminous or asphaltic saturant, which serves to preserve the paper, to prevent access of moisture and to improve the dielectric or insulating properties of the paper. An ex- 'ample of a wire or conductor of this type is shown in Olson Patent No. 2,048,886 in which the wire is rst covered with'strips of paper and then with a l5 braidedsheath to protect the paper against me- Y chanical injury. The whole structure is then completed by treating with a saturating material.

It is very ldesirable to use a hard tough paper for the wrapping immediately in contact with the conductor. Such a wrapping would be a craft paper, preferably of the wrinkle-krinkle type.

When a wire wrapped with a heavy dense paper of this type is saturated inthe usual manner by merely dipping it into a molten saturant, the

saturant material does not penetrate the paper completely andi-thoroughly, or it cannot be depended upon to penetrate freely and thoroughly.

In consequence, the protection of the insulation against the entrance of moisture is imperfect and the insulating qualities of this layer are therefore imperfect. 4

In our present invention we provide an apparatus whereby the iibrous covering of wires or cables may be perfectly saturated in a. 'continuous manner even when the fibrous covering is of a heavy dense nature such as is not readily penetrated by the saturating material.

In the operation of our invention the wire or cable covered with the fibrous covering is passed ,lengthwise or continuously into a vacuum chamber where it is heated and remains for a sulcient time to expel substantially all air and moisture. For example, a vacuum having an absolute pressure of 20 millimeters may be employed and the '45 wire or cable heated to a temperature of approximately 250 F., under which conditions the cable will be freed from substantially all vapors and gases.

The cable or wire passes continuously into the 50 chamber through a seal which prevents air from entering about the cable so that the only/air introduced in the vacuum is that within the cable or wire wrapping. 'Ihe wire or cable remains in the vacuum chamber and subjected to vacuum 55 treatment for a sullicient period of time to permit the complete withdrawal of air from it. During this vacuum treatment the cable is brought to Aa sulcient vertical height and then passes downwardly into hot or molten saturating material t which seals a downwardly opening outlet of the 5 'vacuum chamber. Consequently the wrappings of the wire or cable enter the hot saturating material while still freed from all vapors and gases and with their pores or spaces completely vacuumized. Consequently the hot'saturating liquid 10 readily enters the minute vacuum spaceswithin the fibrous structure and thoroughly penetrates and saturates the fibrous material. vAs this material passes downwardly through the hot molten saturating material, the pressure of the liquid increases to atmospheric pressure at the time that the cable leaves the exit end of the vacuum chamber. This facilitates thepenetration-of the saturant intothe spaces in the brous material. The wire or cable -may then be readily withdrawn under atmospheric pressure. The saturating tank thus serves as a'liquid seal for the exit end of the vacuum chamber.

The various features of the invention are illustrated by way of example inthe accompanying drawings, in which- Fig. l is a diagrammatic elevation of apparatus 'embodying our invention.

Fig. 2 is a diagrammatic sketch showing the Iriavell of the wire or cable in the apparatus of 8- Fig. 3 is an elevation of the apparatus of Fig. 1 foreshortened and 'on a larger scale, and with parts broken away to show the interior of the apparatus. beFig. 4 is an entrance seal to the vacuum cham,-

In the apparatus illustrated in the accompanying drawings, a wire or cable I0 having a fibrous coating to be saturated isdrawn from a drum II through a seal I2 into a vacuum drum I3. After entering the drum I3 the wire is wrapped several times around a rotating drum I4 so as to provide a suilicient period for the withdrawal ofall air and occluded vapors or gases; thence the' wire passes upwardly through a substantially vertical tube or passageway I5 extending upwardly from the drum I3 in a line approximately tangent to the periphery of the drum I4. The passageway I5 forms an extension of the vacuum drum I3 and connects it with an upper chamber I6 of the vacuum system in which there is a rotatable sheave Il. The wire or cable which is still suby jected to vacuum treatment in passing upwardly through the passageway I5 kand into the chamber 55 chambers I3 and II. It will be understood that these heating means are indicated merely dlagrammatically and that the position and arrangement orthe heating means may be varied or changed, or that other means may be employed. 'I'he heating of the cable serves to vaporize any adsorbed moisture in the fibers and decreases theadsorbing tendency of the fibrous vmaterial and, therefore. facilitates-the withdrawal of the gases from the vacuum. Suiiicient time is af-` iorded by the passage of the wire or cable about the drum Il and the sheave II and the passage through the pipe or conduit I to permit allof the water and gases to be withdrawn from the brous coating. For example, fifteen minutes treatment at a high vacuum before immersion in the saturant is generally suflicient to remove all moisture, vapors and gases.

The tank I3 is` heated to maintain the saturant in a mobile liquid condition. In order to prevent chilling and soiidifying of the saturant that is drawn upwardly into the tube I3, they latter is heated by any suitable means. `For example, with a saturant that melts and forms a highly iluid liquid at 250 F., or lower, the conduit I3 as the seal I2, and passes about a capstan 23` may be heated by a steam Jacket 22 to which steam may be admitted through a pipe 23 and exhausted through a pipe 23'.

On entering the tank I3 the :wire is wrapped about a drum 24 a sumcient-number 'of turns to keep it in the saturant bath 2l until the iibrous material is completely saturated. 'I'hen the wire is drawn from the tank through a wiper 23 which may, or may not, be of the same construction which is driven from a motor 21 through a suitable drive 23. Then the wire or cable passes onto a winding drum or reel 23.

'Ihe seal I2 may be of any suitable construction, but that shown in section in Fig. 4 is preierred. In this construction the seal I2 is formed kaiutarci: Y*

and a stationary tubular part fastened in the wall of the tank I3 and has a threaded stem 3| extending parallel to its free end. 'I'his threaded end is joined by 'means of a turnbuckle 32 to the oppositely projecting stem 33 of a collar 34 whereby by turning the turnbuckle 32 in one direction or the other, the collar may be brought toward, or separated from, the tube 30. The space between the tube 30 and the collar 3l is spanned by a piece of rubber tubing securely fastened at its opposite ends to the tube 33 and collar 34. When the collar 34 is moved away from the tube 30, the rubber tubing 35 stretches and contracts and, in this way, may close tightly about the passing cable I0, preventing leakage of air about the latter,'while yet avoiding undue friction.

Through the above invention we are enabled to-saturate wrappings of dense, hard paper such as craft paper uniformly and thoroughly with an impregnating bituminous or asphaltic liquid as, for example, with a blown asphalt. Very eilective insulating qualities are imparted to the wrappings in this manner. For example, a cable formed of a wrapping of wrinkle-krinkle paper saturated by our process with` a blown asphalt has a high dielectric or insulating property and is resistant to deterioration by water or moisture. A sample of such a wire after immersion in water for sixteen hours required voltages of over 10,000 volts to break through. This is not only higher than any voltages and moisture protection that could be obtained on this paper by ordinary saturation, but is higher than that obtainable with non-vacuum saturation or immersion of readily saturable material, such as the porous material used for paper toweling.

What we claim is:

A vacuum chamber for receiving a continuous length of electric conductor having a fibrous wrapping, said vacuum chamber having la seal for said conductor comprising separable tubular members, a rubber tubing engaged at its ends

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