US816428A - Electric cable. - Google Patents

Description

170. 816,428. PATENTED MAR. 27, 1906. H. W. BUCK.

ELECTRIC CABLE.

APPLIGATION FILED JULY 27,1904.

ITIJESSESI HawoldV/BLJcK.

Q v b amfifl to a subwa v,

UNITED STATES PATENT OFFICE.

x 'lIAROLl.) \V. BUCK, ()I NIAGARA FALLS, .NlflV YORK, ASSIHNUR A (.ORPORAIION OF ERAL ELEC'IRH COMPA NY,

T (H lf- NEW YORK.

ELECTRIC CABLE.

Specification of Letters Patent.

Patented March 27, 1906.

A iicaaoifiiia July 27. 1904. Serial No. 218,407.

To (LZZ whom it may concern: Be it known that l, HAROLD W. BUCK, a citizen of the United States, residii'ig at Niagara Falls, in the county of Niagara and State i of New York, have invented certain new and useful improvements in Electric (ables, of

which the following is a specification.

Where a large number of cables are to be located in close proximity to each other, as in it is necessary that the cables when installed be thoroughly fireproof. The object of my invention is to provide such a fireproof installation. It has been proposed heretofore to render i electric cables fireproof by applying to the cable during the process of manufacture it braid which has been previously impregnated with some fireproof liquid. This method of protection, however, has. proved unsatisfaczo tory, because the subsequent coiling and uncoiling of the completed cables at the factor v and during the installation cracks the tireproof braid, which is naturally hard and brittlc, and leaves it full of minute cracks and pores. Under such circumstances in case of a neighboring short circuit or excessive heating in. the conductor of the cable therubber coinpound of the insulation gives off a conibustiblegas which comes out through" these cracks'and burns in the form of numerous littlc gas jets,-Which is practically the equivalent of the rubber burning directly. It has also been proposed to provide the cable, after ithas been installed, with a wrapping of untreated asbestos,'but this is usually no better even where the asbestos is held by a steel binder, for the reason that the heating of the cable-causes the binder fU llKll and uncoil and allow theasbostos wrapping to fall off, orflif the bindcr does not fall off. the rubber i insulation inside of the wrapping melts comes out through the pores of the asbestos, which acts as a. vicl\'-,,and s o n-*-the.cable is dcst ro vcd. Another objection to the uscof untreated asbestos as a wrapping is that it is a good lilsft- {lat-or 'of heat, and conscipi'cnt l the heat of the eable-eonductor is retained within the wrapping, which thereby direct fva sists in increasin gthe temperature of the cable. Furthermore,theuseofsteel tapeorwireto hold theasbestos wrappingi i position is ver expensive. Ilho object of the present invention is ;to install an electric cable which shall be free from any of the above defects.

i i i i left filled,

In carrying out my invention the cables are placed in their final position and then covered with a iii'cproof fibrous material which has previously been impregnated with some fireproof self-hardening liquid. Specifically, I employ a strip of asbestos and soak the same in a solution of silicate of soda and then while still wet wrap itabout the cable in place. The silicate of soda is then allowed to harden and all the pores of the asbestos are so that in case the cable becomes unduly heated the rubber insulation cannot work out through the asbestos and take fire. Furthermore, the asbestos when so treated becomes a very good conductor of heat, and thus assists in maintaining the cable at a low temperature.

in the accompanying drawings, Figure 1 is an elevation of a cable treated in accordance with my invention and showing a single strip of the fireproof wrapping. Fig. 2 is a similar view showing a wrappin composed of two F overlapping strips, and Fig. 3 is a cross-section of asubwav, showing the cable installed. in said dra\\'ings, 1U designates the cable, which is provided with the usual covering 1], of rubber or other insulation, upon the outer surface of which is wound the wrapping 12. According to li] invention the cable is placed in its final position -as. for example; upon the brackets 13 in the subway H. .\s previousl indicated, when thus positioned a strip of asbestos or equivalent fireproof material is soaked in a silicioiis solution. such as silicatc-of-soda solution, and then when thoroughly impregnated it is wrapped about the cable. It isobvious that this wrapping ina v be done. in different wavsrand for illustration [have shown in Fig. I the impregnated asbestos strip 1;, spirally wound about the cable. in Fig. 2 the singlcstrip is replaced by two overlapping strips 1;? and 12". which are also spirallywound. l l'tlfll the above it will be apparent that my invention possesses man advantages over installations of the prior art,

and that while thc covering is hard and brittle it is nevertheless without cracks or pores, since it is not moved after it has hardened upon the cable, but remains solid and honiogcncous. I

lt will be apparent to those skilled in the art that the asbestos inirv be replaced by other fireproof material and that other sclf hardening solutions might bc employed in stead of a silicate-ot-soda solution. I. therefore do not wish my invention to be unduly limited, but aim to cover by the terms of the appended claims all equivalents.

What I claim as new, and desire to secure by Letters Patent of the United States, is

l. The method of fireproofing electric ca bles which consists in placing the cables in 3. The method of fireproofing electric cables which consists in placing the cables in their final position, imn'egnating asbestos with a silicate-of-soda sofution, and wrapping said impregnated asbestos while wet about the cables so as to completely envelop them.

4. The method of fireproofing electric cables which consists in placing the cables in their final position, impregnating a strip of asbestos with a silicious solution, and wra ping the impregnated strip while wet spiral y about the cables so as to completely incase them.

In witness whereof I have hereunto set my hand this 22d day of July, 1904.

HAROLD W. BUCK.

Witnesses:

G. E. BROWN, 1. M. INNES.

Images