204 



THE INDIA RUBBER WORLD 



[April i, 1907. 



THE INSULATION FIELD. 



PROCESS OF FIREPROtJFING CONDUCTORS. 



A PROCESS of making lireproof coniluctors, for vvliich a pat- 

 '^ ent has been issued to A. M. Lougee, consists in coating 

 the conductor wire with a cover of approximately pure rubber, to 

 which are applied several vulcanizable coatings containing insulat- 

 ing and fireproofing ingredients with increasing proportions of the 

 latter in successive coatings. A closely fitting woven wire jacket 

 is next applied, and outside of this a highly heated, thin, vul- 

 canizable, fireproof and electrolysis proof insulating compound. 

 The latter is applied a number of times, until the heated com- 

 pound has permeated the meshes of the wire jacket and become 

 thoroughly incorporated therewith about the individual strands 

 and on both sides of the jacket. Finally a heavy coaling of vul- 

 canizable fireproofing compound is added. ;ind the whole vul- 

 canized together. 



FIREPROOF INSULATED MAGNET WIRE. 



The problem of heat resisting magnet wire has been the study 

 of years, .'\sbestos has been the basis for the insulation of wire 

 of this class mentioned, and inventors long have been trying vari- 

 ous methods of applying asbestos paper or twine to wire. The 

 paper or twine is held upon the wire in most cases either with 

 cotton thread or a heavy coating of organic paint. But while 

 admirable otherwise, cotton, is incapable of resisting continuously 

 a temperature much above the boiling pomt of water. 



The Heany fireproof insulated magnet wire is the latest form 

 produced. It diflfers from previous attempts inasmuch as the 

 asbestos is used in the fibrous condition, without being worked 

 into twine or paper. The fibers of asbestos arc applied in a filmy 

 condition to the conductor, and then saturated with an inorganic 

 cement which forms a homogeneous, durable, flexible, uniform 

 covering, in the nature of a paint which can be built up from a 

 thickness equivalent to a single wrap of cotton to any desired 

 diameter. The result of this structure is to produce an insulation 

 that cannot be destroyed by heat, no matter of what degree. 



Cotton wound coils may burn out in dififerent ways, but what 

 most commonly happens is the gradual carbonizing of the cotton, 

 rendering it friable and conducting. With fireproof insulation the 

 gradual roasting is obviated, and in consequence the coils have an 

 almost indefinite life instead of from six months to a year, which 

 seems to be the average life of a street railway field coil. This 

 gradual roasting is the fate of any insulation that contains a large 

 percentage of organic matter, whether it also contains asbestos 

 or not. 



TWO NEW INSULATING COMPOUNDS. 



A NF.w insulating compoimd for which a patent has been 

 granted to Samuel G. Peimcy is referred to as having the advan- 

 tage of being durable, fireproof, capable of being readily prepared 

 and easily applied, inexpensive and efficient as an insulator. It is 

 stated that it will resist concussion and vibration imparted to the 

 metal to which it is applied and may be as conveniently and effec- 

 tively used in repairs as in original application. The compound 

 consists of fibrous asbestos, comminuted mica, a double silicate of 

 soda, and a solution of soap, and is especially designed for insulat- 

 ing metallic surfaces by direct application to the surface of the 

 metal. 



.The silicate is created a double silicate by the addition of about 

 15 to 20 per cent of a strong solution of lime, thereby making the 

 silicate impervious to water or any chemical change. It is also 

 treated at the same time and in the same manner to a 15 or 20 

 per cent solution of soap shavings dissolved in hot water, which 

 chemically changes its stiff character into pliability. The metallic 

 surface is first coated with the silicate thus prepared, over which 

 is then given a coating of the asbestos, which is then allowed to 

 dry, after which a coating of the prepared silicate is again given, 

 followed by a coating of comminuted mica. After this has dried 

 as manv additional coatings of the mica and asbestos mav be 



given it as may be desired, dependent upon the insulating effect 

 and insulating property needed. .-Xn outside or finishing covering 

 or coating of paint or liquid tar paint neutralized with a 10 per 

 cent lime solution, may then be given. 



Anotlier patent issued to Mr. Penney relates to an insulating 

 compound that may be applied either as a paint, varnish or paste 

 to bond paper, cotton cloth, metallic surfaces or wherever a coat- 

 ing of insulated compound is required, and may be used either as 

 an air drying varnish or it may be baked on the material to be in- 

 sulated in a suitable oven. .As a varnish or paint the compound 

 consists of maltha, 20 per cent; byerite. 30 per cent; benzin, .12 

 per cent : carbon tetrachlorid, 38 per cent. In compounding these 

 ingredients the maltha and byerite, together with a little colo- 

 phony to act as a flux, are placed in a receptacle and subjected to 

 heat until fused, and then while still hot the benzin and carbon 

 tetrachlorid are added. The compound is then allowed to cool 

 and is drawn off. .X convenient form of maltha is ordhiary 

 asphalt. 



ELECTRICAL TRADE NOTES. 



New York has now a well equipped laboratory for the special 

 testing of india-rubber and gutta-percha covered wires, both for 

 conductivity, insulation resistance, and tensile strength. Indeed, 

 when it comes down to the latter quality, the work is not confined 

 to insulated wire, but broadens out into the general line of me- 

 chanical rubber goods. Tlie headquarters of this insulation insti- 

 tution is the Electrical Testing Lab-iratory, at Eightieth street 

 and East End avenue. New York. 



Linen tape for all the varied uses of the electrician is being put 

 on the market by M. W. Dunton & Co., of Providence, Rhode 

 Island. 



As showing the excellence of Okonite rubber insulation it is 

 interesting to know that the plain insulation, without any protec- 

 tive covering whatever, is soaked three days in water before being 

 tested. 



In answer to an inquiry, the Bishop Gutta-Percha Co. (New 

 York) are not only remarkably well equipped for all kinds of 

 gutta-percha insulation, but they make a very high grade rubber 

 insulation as well. 



Johnson & Phillips, Limited, of the Victoria Works, Charlton, 

 Kent, England, are out with a signed invitation, which bids any- 

 one interested to come to their great cable works and see the 

 whole process of insulated cable making from start to finish. 



The Dickinson Manufacturing Co., formerly the Dickinson 

 Hard Rubber Co. (Springfield, Massachusetts'), are very largely 

 increasing their output of composition devices for an innumerable 

 variety of insulating purposes. 



The National Wire Corporation (New Haven, Connecticut) 

 has been placed in the hands of receivers. This was on the re- 

 quest of the holding company, the National Steel and Wire Co., 

 a JNIainc corporation. The temporary receivers appointed were 

 Henry L. Hotchkiss, president of The L, Candee & Co. (rubber 

 manufacturers), and Homer Wise, of New York. The perma- 

 nent receivers, appointed January 4. were H. Stuart Hotchkiss 

 and F. B. Farnsworth, both of New Haven, under bonds of $150,- 

 000 each. The liabilities are reported at $300,000. 



The installation of the new Summer lane station, m connection 

 with the electricity supply of Birmingham. England, lately com- 

 pleted, is a very notable piece of work. Tlie cable xvork was car- 

 ried out by Callender's Cable and Construction Co., Limited. 

 The direct current cables are insulated with vulcanized india- 

 rubber and fireproofed with asbestos braid. The alternating cur- 

 rent cables are of the three core, paper insulated, lead covered, 

 armored type, and have a subw^ay to themselves. 



The St. Helens Cable and Rubber Co.. Limited (Warrington, 

 England) advertise that they have made very favorable contracts 

 for raw rubber for the season of 1907 and are going to give the 

 benefit of it to their tire customers. 



