Improvements in the Manufacture of Electrical Insulating Materials.
Year: 1890

page_text: Date of Application, 21st Oct., 1890
Complete Specification Left, 20th Aug., 1891-Accepted, 26th Sept., 1891
Improvements in the Manufacture of Electrical Insulating
Materials.
I, JAMES RAPER THAME of 17 Godolphin Road Shepherds Bush London in
the County of Middlesex Mechanical Engineer do hereby declare the nature of
this invention to be as follows:-
This invention relates to improvements in the manufacture of electrical insulating
materials intended to take the place of ebonite, slate, porcelain etc. etc. In the
manufacture of this insulating material or materials. I use as the base pure or
nearly pure cellulose prepared chemically from any suitable fibre such as cotton, linen,
wood, flax, hemp, & the like, the cellulose so obtained is moulded by pressure into
the desired shape & is afterwards treated with a solution of gum or gums in
alcohol or other suitable medium or I may use any suitable drying oil which may
be oxidized or otherwise treated to increase the rapid after drying of same with
or without the addition of resin gum etc. said drying oils & resin or gum may be
dissolved in a suitable medium such as naptha, and to ensure perfect saturation of
the moulded articles, may cause the above named solutions to be forced into the
said moulded articles by means of a vacuum & pressure in suitable tanks, the
solvent may afterwards be recovered by distillation or heating of the goods in
closed tanks the solvent being condensed in the usual way.
For the production of a cheaper material I may use any suitable kind of waste
fibre such as willow waste from paper mills waste fibre or dust from cotton or other
works.
When the material is intended to replace sheets or articles of slate I may use
slate dust combined with drying oils & resin, or soda, or potash silicate the com-
bination of the slate dust & drying oils or soda or potash silicate being submitted
to a heavy pressure in moulds of the desired shape.
In the manufacture of conduits casings & the like for containing cables for
underground circuits I prefer to use a mixture of Portland or other cement which
is mixed with a proportion of paper pulp or other suitable fibre or materials in a
dry or wet state with or without ballast sand, or other materials, said mixture is
poured or rammed into suitable moulds, having a contracting & expanding core and
around this core I place a tube of metal or wire said tube of metal or wire being
corrugated or otherwise made to give the best toothing to the mixture of cement etc.,
the conduits so made may after being partially or wholly dried be treated with any
suitable materials possessing high insulating properties such as wax, ozokerite,
pitch, resin tar etc. etc. and to ensure perfect saturation of the said conduits the
above named insulating materials may be forced into them by the same means as
described above for the saturation of the articles made from cellulose etc. etc.
n 3 this 01st day of October 1800

page_text: COMPLETE SPECIFICATION.
Improvements in the Manufacture of Electrical Insulating
Materials.
I, JAMES RAPER THAME formerly of 17 Godolphin Road, but now of 112 St.
Stephens Avenue, Shepherds Bush, in the County of Middlesex, Mechanical
Engineer 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 the manufacture of electrical insulating
materials intended to take the place of ebonite, slate, porcelain, etcetera, etcetera.
In the manufacture of this insulating material and materials I use as the base
pure or nearly pure cellulose, prepared chemically. from any suitable fibre; such as
cotton, linen, wood, flax, hemp and the like, the cellulose so obtained is moulded by
pressure into the desired shape and is afterwards treated with a solution of gum or
gums in alcohol such as shellac using 4 pounds of gum to one gallon of alcohol
preferably methylated spirit or other suitable medium or I use any suitable drying
oil such as linseed oil which may be oxidized or otherwise treated to increase the
rapid after drying of same with or without the addition of resin, gum, ctcetera said
drying oils and resin or gum may be dissolved in a suitable medium such as naptha
and to ensure perfect saturation of the moulded articles using by preference a
mixture of part oxidized oil and 1 part resin the whole mass being thinned down
by the addition of a sufficient quantity of commercial naptha I cause the above
named solutions to be forced into the said moulded articles by means of a vacuum
and pressure in suitable tanks the solvent may afterwards be recovered by dis-
tillation or treating of the goods in closed tanks the solvent being condensed in the
usual way.
For the production of a cheaper material I use any suitable kind of waste fibre
such as willow, waste from paper mills, waste fibre or dust from cotton or other
works. When the material is intended to replace sheets or articles of slate I use
slate dust combined with drying oils and resin in the proportion of 10 parts slate
dust to 5 parts of soda, or soda or potash silicate the combination of the slate dust
and drying oils or soda or potash silicate being submitted to a heavy pressure in
moulds of the desired shape.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed I declare that what I
claim is :-
1: The preparation or manufacture and use of electrical insulating materials
from cellulose obtained from chemically prepared wood pulp the material after
being moulded being treated with gums or resins to render it hard, the solvent of
the gums being distilled off for reuse or removed substantially as set forth.
2: The preparation or manufacture and use of insulating material by incor-
porating slate dust (i.e. waste slate ground up) with soda or potash silicate the
plastic material so obtained being first slowly dried and afterwards submitted to a
red heat in a suitable furnace or retort substantially as set forth.
Dated the 20th day of August 1891
WM. BROOKES & SON,
55 & 56, Chancery Lane, London, Agents for the Applicant.