Publication: Electrical World
New York, NY, United States
Notes on Paraffin Insulation.
BY DAVID BROOKS.
In your number of November 29th, in an article headed "Precious Paraffin," and speaking of it as, "A wonderful substance is that snowy, pure, tasteless opalescent wax," etc., etc.
From the "Encyclopaedia of Chemistry," published by Lippincott, I quote as follows: "In 1830, Reichenbach obtained from the tar produced when the wood of the red beech was destructively distilled, a white crystalline body to which he gave the name of paraffin, on account of its being difficultly acted on by chemical agents. A year later Dr. Christison, of Edinburgh, obtained the same substance from Rangoon petroleum and named it petroline. From these sources if was obtained in small quantities and with much labor, so that it remained many years merely a chemical curiosity."
As early as 1845, while engaged under Henry O'Reilly, I had a hand in devising an insulator for overhead wires. In 1848 and '49 it took the form of a pressed glass with an iron shield. A cramp hook was molded into the glass, when the latter was in a molten state, and this insulator was suspended from a cross-arm. We soon found this insulator to be very defective on account of the cracks in the glass. These cracks would absorb moisture which remained in the insulator, and produce an escape of the current, even in clear weather.
About the years 1858-4 we took out these insulators, heated or boiled them in beeswax, drove out the moisture, and filled those crevices with the wax. We used spermaceti, stearine and like substances for that purpose. All our experiments in making an insulator perfect were to detect a current by the tongue — galvanometers were not in use in those days. We had a small hand furnace which the men carried along the line, treated the insulators in this manner, and by that means kept the insulation of the lines in good condition. About the year 1857, while walking past Stevenson's oil store in Second street, between Chestnut and Walnut streets, Philadelphia, I noticed in the window a block of a singular looking substance resembling spermaceti. I went in and asked the name of it, and was told "paraffin." and that it was made from petroleum. I procured a few pounds and applied it to defective insulators in the manner before described with very favorable results. During this time I was superintendent and director of the Atlantic & Ohio telegraph lines. E. Hall Ogden, now deceased, manufactured the insulators, and I find by his books, as early as 1858 and '59, that he purchased small quantities of paraffin and applied it to the insulators before they left his works. The insulators thus used were for repairs, and no very distinct results could be obtained until 1862, when we put up an entire new set of poles and wires between this city and Pittsburgh, on the opposite side of the road being an additional line of two wires.
Alter some two years' use of these wires I made application for a patent, and Prof. Page granted a claim, which, reads as follows: "The use of paraffin applied to insulators for telegraph wires in the manner described, or in any other manner by which the same result is obtained." The word paraffin was applied to candles as a description, because made of such substances and so treated as to resemble paraffin.
Mackintosh spoke of using it to preserve the sheathing of cables as early as 1855 in an English patent, but in his specifications he states he uses paraffin preferably made from animal matter, evidently showing that real paraffin was not used, except in the sense that a mixture of india rubber and sulphur is called ebonite from its resemblance to ebony.
Anterior to the discovery of mineral oil in large quantities and the products distilled therefrom, paraffin was much too costly a substance to be used for insulating purposes.
The patent granted me to which I have made reference, was issued Nov. 24, 1864, but was reissued in Aug. 1867. So far these notes are historical on my connection with the use of paraffin.
Its name was given by Reichenbach, its discoverer, from parum affinis — little affinity.
In all the German, French and English text books it is spelled without an e, the word ending with n, and I have always spelled it so myself.
Pure paraffin, instead of being pearly white or opalescent, has an amber color. The pearly white appearance is produced by the use of acids and soda, and that kind does not stand as high as an insulator as paraffin that is purified without the use of those agents. In this respect I have often thought that it resembled glass which is made clear and transparent by the use of metallic oxides — like what is known as "French plate-glass," which is comparatively a poor insulator.
Glass of the highest insulating properties is made of little or no metallic oxides. The most perfect Leyden jar is made from pure sand and kaolin.
When we find it in a solid stare we call it "paraffin," when in a liquid state we call it "petroleum" or "refined petroleum." In the solid state the English call it "paraffin wax," and in the liquid state "paraffin oil."
Chemically they are the same, but there are different grades designated by their melting points.
Despite the numberless uses to which paraffin is now applied, its real value is scarcely known. One of its most remarkable properties is its repellence of moisture, and how to take advantage of that principle was an object and study of mine for years, which finally resolved itself into the use of a blown glass bottle inverted and securely protected by an iron shield, and the inner surface of the inverted bottle being coated with paraffin.
An insulator thus made is not affected by rain or moisture.
An ordinary glass insulator in rain will give a deflection of a hundred thousand divisions with an astatic galvanometer, when with the same battery a paraffined bottle insulator will not show one division.
A No. 8 iron wire, insulated with the paraffined bottle insulator, forming a circuit of one hundred and thirty miles, with thirty-five relays of a hundred and fifty ohms each, is worked on the Pennsylvania Railroad, to report the passage of trains, with as much ease in the hardest rain as an ordinary circuit of that length is worked in clear weather. This cannot be done with any other insulation, even if a wire giving a resistance of one ohm per mile were used with that amount of resistance in the form of relays in the circuit.
In the course of four or five years these insulators are taken out and rinsed in paraffin and their insulating properties are restored to their original degree. The cost of this work is far less than the labor and expense of replacing the ordinary broken glass insulators.
A No. 10 iron wire insulated with the bottle insulator is worth for business three times as much as a No. 4 gauge iron wire in rain insulated with the ordinary insulator.
How many wires are open and useless in order that others can be worked at slow pace in hard rain? Millions of dollars might have been saved, by the use of paraffin and lighter conductors, that have been spent within the past twenty years in heavy conductors, to overcome the effects of poor insulation.
|Keywords:||General : David Brooks|
|Researcher notes:||E. Hall Ogden operated the Philadelphia Malleable Iron Works; a hardware manufacturing establishment at Ninth & Jefferson Streets, Philadelphia, PA.|
|Supplemental information:||Patent: 45,221 Reissue Patent: 2,717|
|Date completed:||May 4, 2009 by: Bob Stahr;|