US1901005A - Manufacture of loaded electric signaling conductors - Google Patents

Description

March 14, 1933. w. 5. SMITH ET AL MANUFACTURE OF LOADED ELECTRIC SIGNALING CONDUCTORS Filed May 25, 1931 Patented Mar. 14, 1933 WILLOUGHBY STATHAM r orries. 7 1

SMITH, or BENGHAMS,, NEWTO1\T rorrrnronn, HENRY JOSEPH GARNETT, 0F LYMNE, SOLEFIELDS, SEVENO'AKS, AND JOHN NORMAN DEAN, OF ORPINGTON, ENGLAND MANUFACTURE OF LOADED ELECTRIC SIGNALING GONDUGTQBS Application filed May 25, 1981, Serial 110.539,!)64, and. in Great Britain February 14, 1931.

This invention relates to improvements in the manufacture of loaded electric signaling conductors, and more particularly to conductors loaded with a wire or tape of magnetic material wound upon the conductor.

Such conductors are usually subjected to an annealing treatment in order to develop magnetic permeability in the loading. After winding on to the conductor the loading tape or wire, the latter, even after annealing,

tends to grip very tightly the conductor with the result thatthe magnetic properties are apt not to be fully developed.

To overcome this strained condition of the loading tape it is the practice to employ what is known as a spacer between the loading tape or wire and the conductor, which spacer is removed during the subsequent annealing operation.

Various forms of spacer have been proposed, but up to the present all those which are of a carbonaceous nature, such for example as a paper tape or a combustible thread, have not proved satisfactory owing to the deposits of carbon which are formed in the annealing furnace.

The object of the present invention is to overcome these objections to the use of acarbonaceous spacer by removing the carbon deposit. I

Experiments have been made with oxygen, which has been introduced in controlled proportions with the inert gas into the annealing furnace with the object of reacting with the carbon and other reducing bodies that may be present. It has however proved practically impossible to control the inlet of oxygen so that the reducing bodies are fully oxidized while at the same time the conductor is unattacked by the oxygen.

According to the present invention con ductors having a spacer of a carbonaceous nature, are treated in an atmosphere containing a gas, such as water vapor containing combined oxygen, which oxygen is capable of reacting at the temperature of the annealing operation with the carbon or other reducing bodies formed.

An atmosphere consisting of an inert gas e. g. nitrogen admixed with water vapor the carbon in accordance with the equation C+H O=CO+H p and indeed carbon monoxide has been detected in the gases issuing from the tube at the end where the conductor leaves the furnace. I

The proportion of water'vapor admixed 1 With e. g. the nitrogen does not seem to be at alleritical provided sufficient wateris present to oxidize the carbonto carbon monoxide. Loaded conductors have been successfully heat-treated in an, atmosphere consisting almost'entirely of water-vapor. The nickel alloy loadingmaterial of the conductoris substantially unaffected when it has been heat-treated in an atmosphere containing only a relatively small or moderate proportion of water-vapor, but is covered with a very thin film, probably of oxide, when tively thick tape, e.g. .006 inch thick, it is preferable when very thin tape e. ,g. only .001 inch thick is used, to employ such a proportion of water vapor that no oxidation of the metal surface occurs.

The water may be introduced either in the form of steam or as drops of liquid water through a special entrance tube into the furnace or it may be sprayed in with the nitrogen.

As has been stated above, the gases issuing from the end of the furnace tube contain carbon monoxide, the highly poisonous nature of which is well known. In order to prevent this gas escaping into the air of the room,-an adapter is attached to the exit end of the furnace tube, which adapter maybe made of copper, brass, gun-metalor anysuitable material. -Two forms of adapters are illustrated in Figures 1 and '2 of the accompanying drawing which are sectional views. i The adapter may consist ofa length of attached to the heating tube indicated at 3 so as'to restrict for a considerable distance that mouth of the heating tube through which the conductor leaves the furnace, this tapered portion of the tube fitting the conductor fairly closely.

A branch pipe 4 to which a suction pump (not shown) is attached, is fitted to the heating tube at or adjacent the beginning of the restricted portion.

The carbon monoxide and other gases from the furnace are urawn off by the suction pump through the branch pipe 4 and are prevented from escaping into the air of the room by the steady intake of air (indicated by the arrows a) drawn in by the action of the pump through the narrow opening round the emerging conductor. As this causes a vacuum in the tube with con sequent intake of air at the lead in end together 'with the nitrogen and steam, it is better to provide a partition in the heating tube so as-to form a separate chamber at the exit end and to control the pressure in this chamber so that it is only just below that o1 the atmosphere. Such an arrangement is i shown in Figure 2 in which the adapter consists of acylindrical container 5 having axial holes 6 for the passage of the conductor. 7 and 8 are inlet and. outlet pipes connected to the chamber 9 of container 5. Alternatively a controlled amount of air or oxygen may be admitted into the furnace tube at the end of the hot zone, suiticient to oxidize the reducing gases such as carbon monoxide, hydrocarbons (if present) and hydrogen, to carbon dioxide and water. The disadvantage of this method is that it is difficult so: to adjust the amountof air or oxygen admitted that the reducing gases are completely oxidized while the heated conductor is unattached by the oxygen.

What we claim is I. In the manufacture of aloaded sig naling conductor having a spacing materlal applied between the central conductor and the loading material, wherein said spacing material is removed during the process of heat treating the conductor in order to provide a space betweenthe conductor and the loading material retaining a carbonaceous material, the method of subjecting said car-' bonaceous material to an inert atmosphere containing water vapour, which water vapour reacts at the temperature of the heat treatment with the retained carbonaceous material for preventing attack of said carbonaceous material upon said conductor.

2. In the manufacture of a loaded signaling conductor having a carbonaceous material applied between the central conductor and the loading material, wherein said carbonaceous material is removed during the process of heat treating the conductor in order to provide a space between the conductor and the loading material while leaving a carbon residue, the method of subj ecting said carbon residue to an atmosphere consisting of a mixture of nitrogen and water vapour for the purpose of dissipating said carbon residue and preventing the at-

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