Improvements in and relating to the Manufacture of Insulating Compositions for Electrical Uses.
Year: 1890

page_text: Date of Application, 12th Dec., 1890-Accepted, 7th Feb., 1841
COMPLETE SPECIFICATION.
Improvements in and relating to the Manufacture of Insulating
Compositions for Electrical Uses.
I TURNER D. BOTTOME of the Town of Hoosick in the State of New York U.S.
Electrician, do hereby declare the nature of this invention, and in what manner
the same is to be performed to be particularly described and ascertained in and by
the following statement :-
This invention relates to improvements in compositions for making articles for
electrical purposes, and it includes the process of preparing the same and the
various steps and manipulation of the product substantially as hereinafter more
fully described.
An important feature of the said invention consists in a novel method of
preparing electrical insulating compounds that are entirely free of hygroscopic
substances and at the same time rendering the same stronger and tougher than
heretofore.
The said invention comprises other improvements hereinafter set forth.
The objects of this invention are to produce a cheap and easily manipulated
mass from which various forms of electrical insulators having very high resistance
may be made by simply moulding or pressing the mass while at an ordinary
temperature, then drying and finally heating the same to form an article that will
withstand all of the usual disintegrating influences that ordinarily occur
insulators for electrical purposes, among which may be mentioned, sudden changes
of temperature, mechanical strains, effects of acid or alkaline vapours or dampness,
high electrical potentials, and so forth.
to
In carrying my invention into practice, I employ powdered silicon di-oxide
(otherwise known as quartz) selecting that of the very finest state of division to be
found in the market, I then dry the powder by subjecting it to a moderate heat for
the purpose of eliminating and freeing it of dampness, occluded gases and other
objectionable substances or impurities.
I then take a sufficient quantity of a solution of the crude sodium or potassium
silicate of about 40 degrees Beaume, to make a plastic mass with the previously
prepared powdered quartz, to which is added about 3 to 5 or more per cent.
of colouring substance when some particular colour is desired, these ingredients
are then thoroughly and intimately mixed together and so proportioned that a
workable plastic mass of doughy consistency is formed, portions of the mass so
prepared are placed or forced in moulds and pressed or otherwise shaped by
suitable mechanical means into such articles as may be desired. The articles thus
formed are placed in a warm place and allowed to become thoroughly dry and hard,
they are then subjected to a red heat which results in all of the volatile matter
being driven off so as to leave nothing but pure oxide of silica behind in
a very
and coherent state.
hard
The articles thus finished will present a slightly roughened surface and when
no colouring substance has been added to the mixture the articles will be of a
grey white colour, where a cheap and effective insulator is required no further treat-
ment will be necessary.
As a final finish to the articles they may be immersed in a mixture composed
of twenty parts of sodium silicate mixed with three parts each of powdered
quartz and precipitated chalk or powdered chalk and two parts of borax. After
this coating has become dry the articles must be heated to redness which causes the
glaze or enamel to fuze and form a bright and smooth surface. This final enamel
finish improves the quality of the insulation when the same is to be used in
damp places, and when a certain colour is desired various ingredients may be

page_text: added to the enamel mixture, thus for a clear white the addition of a small
quantity of arsensic trioxide is very effective. For black the oxides of manganese
are suitable.
For certain purposes metals may be imbedded in the mass while it is yet plastic
and moulded directly therein, the mass may then be dried and finally heated as
before described. By this means caps or bases for incandescent electric lamps
may be made with the metallic conducting pieces firmly secured. Among other
uses the composition may be adapted to, may be inentioned that of replacing mica
between the bars of commutators for dynamo electric machines, the mass is made
as thin in consistency as can be easily worked and then is simply forced in the
interstices and allowed to dry, after moderately heating an excellent insulation will
be formed for the purpose superior to mica in every respect. Other uses such
as the manufacture of insulating blocks, washers, tubes, switch bases and fittings,
incandescent lamp fittings and in fact any article for electrical purposes where
strength imperviousness to disintegrating influences, and high insulating properties
are required. In all cases where possible it is best to use the composition with
as large a proportion of alkaline silicate as can be conveniently worked as the
strength of the finished articles depend upon the quantity of the silicate in the
mixture.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is―
1. The herein described composition consisting of silicon dioxide made into a
plastic mass with a solution of an alkaline silicate, which is dried and subjected
to a red heat substantially as described.
2. A composition for making moulded or pressed electrical insulators, consisting
of powdered quartz mixed with a solution of sodium or potassium silicate to a
plastic consistency in which metallic pieces are embedded, dried and baked,
substantially as and for the purpose described.
3. A composition for making moulded or pressed electrical insulators, consisting
of powdered dried quartz mixed into a plastic mass with an alkaline silicate
having metals imbedded or moulded therein, then dried and coated with a glazing
mixture and finally heated to redness as specified.
Dated this 24th day of November 1890.
TURNER D. BOTTOME.