IMPROVEMENTS IN THE PREPARATION OR PRODUCTION OF INSULATING MATERIALS OR ARTICLES.
Year: 1882

page_text: LETTERS PATENT to John Ambrose Fleming of Hampstead in the County of
Middlesex Doctor of Science for an invention of "IMPROVEMENTS IN THE
PROVISIONAL SPECIFICATION left by the said John Ambrose Fleming at
the Office of the Commissioners of Patents on the 22nd May 1882.
JOHN AMBROSE FLEMING of Hampstead in the County of Middlesex Doctor of
Science "IMPROVEMENTS IN THE PREPARATION OR PRODUCTION OF INSULATING
MATERIALS OR ARTICLES.
"
My Invention relates to the preparation or production of Insulating materials
or articles that is to say materials or articles which when used for such purpose are
capable of interrupting the communication or preventing the escape of electricity
and it has reference partly to former Inventions in respect of which I obtained
Letters Patent dated the 23rd April 1881 No 1762 and the 5th December 1881
No. 5309.
According to one part of my present Invention I prepare the materials by taking
solid wood (preferably English poplar) and thoroughly desiccating the same either
in a vacuum, or by superheated steam or otherwise, and then impregnating it under
pressure with a mixture of melted Bitumen or asphalte, and substances of the
paraffin, anthracene, or resin type Among the substances of the paraffin type
which I may use in the said mixture are paraffin proper, Hatchettine or mineral
tallow and Sheererite. Among the substances of the anthracene type which may
be used are Anthracene Napthaline pyrene, and chrysene. The resins which may
be used are resins either fossil or recent. I may employ in one and the same
mixture with Bitumen or asphalte one of the substances of either type separately
or two or more of them in conjunction, or I may employ together substances of
two or all of the types in conjunction with Bitumen or asphalte
The material thus prepared is cut or shaped with tools into the required form.
Or in lieu of employing solid wood I take wood in a finely divided condition,
or other vegetable fibrous material such for example as wood flour, bran, straw,
cotton, jute, hemp papier maché in a finely divided condition, or asbestos and
Di 131

page_text: having thoroughly desiccated the same in a vacuum, or by superheated steam or
otherwise I saturate or impregnate it under pressure or not with one of the
mixtures before mentioned, and then mould the mass under pressure into the
required shape.
Or in lieu of using solid wood or materials in a finely divided condition I
produce articles such for example as battery cells, telephone cases, pipes or tubes
by taking compressed wood flour made up in the forin of sheets like paper, and
cutting or moulding the same into the required form, thoroughly desiccating it in
a vacuum or by superheated steam or otherwise, and then saturating or
impregnating under pressure the articles thus partially prepared with one of the
mixtures before mentioned or with melted paraffin wax or with a mixture of
melted paraffin wax and resin.
The proportions in which the substances constituting the mixtures before
mentioned are used may be varied but the following proportions will give good
results
When Bitumen, or asphalte with substances of the Paraffin, anthracene or resin
type are used
Bitumen, or asphalte about 2 parts by weight
Substances of paraffin anthracene or resin type say from 1 to 2 parts by weight
When paraffin wax and resin are used
Danathin

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Ambrose Fleming in the Great Seal Patent Office on the
18th November 1882.
JOHN AMBROSE FLEMING of Hampstead in the County of Middlesex Doctor of
Science "IMPROVEMENTS IN THE PREPARATION OR PRODUCTION OF INSULATING
MATERIALS OR ARTICLES
">
My said Invention relates to the preparation or production of Insulating
materials or articles that is to say materials or articles which when used for such
purpose are capable of interrupting the communication or preventing the escape of
Electricity and it has reference partly to former Inventions in respect of which I
obtained Letters Patent dated the 23rd April 1881 No 1762 and the 5th December
1881 No 5309.
According to the first part of my present Invention I prepare the materials by
taking solid wood (preferably English poplar) and thoroughly desiccating the same
either in a vacuum or by superheated steam or otherwise and then impregnating
it under pressure with a mixture consisting of melted Bitumen or Asphalte incor-
porated with a substance or substances of the resin type and a substance or
substances of the paraffine type or of the anthracene type or of both the paraffine
and anthracene types. Among the substances of the paraffine type which I may
use in the said mixture are paraffine proper, Hatchettine or mineral tallow and
Sheererite the point to be looked to being that the melting point should not be
too low. Among the substances of the Anthracene type which may be used are
Anthracene, Naphthaline, pyrene, and Chrysene, similar considerations also
applying here. The resins which may be used in, this part of my Invention are
the substances known commercially as "resin" or "rosin which are the exudation
of various species of pines and firs.
The material thus prepared is cut or shaped with tools into the required form.
According to the second part of my Invention in lieu of employing solid wood
I take wood in a finely divided condition or other vegetable fibrous material such
for example as wood flour, bran, straw, cotton, jute, hemp, papier maché, in a finely
divided condition and having thoroughly desiccated the same in a vacuum or by
superheated steam or otherwise I saturate or impregnate it under pressure or not
with a mixture consisting of melted Bitumen or Asphalte incorporated with a
substance or substances of the resin type in conjunction or not with a substance
or substances of the paraffine type or of the anthracene type or of both the
paraffine and anthracene types and then mould the mass under pressure into the
required shape. The substances of the paraffine and Anthracene types which may
be used are the same as in the former part of my Invention. Those of the resin
type which may be used are those mentioned above with the addition of the fossil
resin, amber, provided that (if amber is used) neither paraffine nor Anthracene is
used or is only used in so small a proportion that it does not affect the
practicability of effecting a thorough mixture of the ingredients of the mixture
I find that the melting point of Amber is too high to admit of its being readily
made to mix with substances of the paraffine and anthracene types for the purposes
of my Invention.
In order that my Invention may be perfectly understood I shall now proceed
particularly to describe the best methods with which I am acquainted of carrying
the same into effect.
In carrying out the first part of my Invention I take solid wood (preferably
English poplar) thoroughly desiccated either in a vacuum (say for example in the
manner described in the Specification to my said former Letters Patent No. 1762

page_text: of 1881) or by superheated steam or otherwise by the aid of any one of the well known
types of apparatus for such purposes and I then impregnate it under pressure
(preferably in the manner described in the last mentioned former Specification)
with the following mixture.
I take what is commonly called paraffine wax and reduce the same to a molten
condition and then add to it resin of any one of the types of that product above
mentioned in that behalf (by preference previously comminuted) in the proportion
of say about two parts by weight of paraffine wax to one part by weight of resin
and to this mixture I add sufficient Bitumen or Asphalte (also by preference
previously powdered) to render the whole perfectly black without impairing its
fluidity when kept at a temperature of say about 200° Centigrade. It should be
observed that the object of using the Bitumen or Asphalte is to obtain an
impregnating material with a higher melting point than is attainable when paraffine
wax and resin are alone employed.
The mixture having been maintained at the said temperature and stirred for a
sufficient length of time for the whole of the ingredients to become thoroughly
incorporated is then ready for use for the impregnation of the wood as hereinbefore
described.
Although for ordinary insulating purposes I prefer to compose the impregnating
mixture as hereinbefore described yet I may substitute in the said mixture for
what is commonly called paraffine wax other or others of the substances of the
paraffine type or one or more of the substances of the Anthracene type as herein
above stated or I may use one or more of the substances of both the paraffine and
Anthracene types in conjunction, it being clearly understood that Bitumen or
Asphalte and resin are in all cases employed.
The material thus prepared is cut or shaped with tools into the required form.
In carrying out the second part of my Invention I take wood flour, or wood
reduced to a fine state of division, or other vegetable fibrous material such for
example as bran, straw, cotton, jute, hemp, papier maché in a finely divided
condition, and thoroughly desiccate the same either in a vacuum (say for example
in the manner described in the Specification to my said former Letters Patent
No 1762 of 1881) or by superheated steam, hot air or otherwise. I also take equal
parts by weight of Bitumen or Asphalte and Amber, the Bitumen or Asphalte
being first comminuted and the amber prepared by preliminary heating the same
so as to render it more easily fusible and then reducing it to the state of powder.
I then introduce the vegetable fibrous material in a finely divided state together
with the prepared Bitumen or Asphalte and amber (in the proportion of say about
equal parts by weight of the finely divided vegetable material and of the Bitumen
or Asphalte and Amber taken together) into a drum and subject the same to an
elevated temperature (of say about 200° Centigrade) whilst continually stirring
the mixture for a sufficient length of time for the whole to become thoroughly
incorporated. I then introduce the material thus prepared into a mould of the
required form (by preference 'previously warmed) and subject it to pressure as
described in the Specification to my said former Letters Patent No 5309 of 1881
and I allow the material to remain in the mould until cool when it is taken.out
and will be found to have become perfectly hard and to possess high insulating
qualities.
.:
For some purposes I may substitute for Amber ordinary resin or resins either
with or without the addition of Amber but in all cases in conjunction with Bitumen
or Asphalte and I may in some cases add small quantities (say for example in the
proportion of about from 5 to 10 per cent of the Bitumen or Asphalte and resin used)
of one or more of the substances of either the paraffine type or of the Anthracene type
before referred to or both of such types. For ordinary insulating purposes however
I prefer the mixture above mentioned.
*The proportions in which the several ingredients are employed may be some-
what varied according to circumstances and the exigencies of particular cases but
those mentioned have been found to give good results in practice.

page_text: Having now described and particularly ascertained the nature of my said
Invention and the manner in which the same is or may be used or carried into
effect I would observe in conclusion that what I consider to be novel and original
and therefore claim as the Invention secured to me by the herein before in part
recited Letters Patent is :-
First The preparation or production of Insulating materials or articles by the
employment of wood deprived of its moisture and impregnated under pressure with
a mixture consisting of melted Bitumen or Asphalte incorporated with a substance
or substances of the resin type as herein set forth and also with a substance or
substances of the paraffine type or of the Anthracene type or of both the paraffine
and Anthracene types substantially as hereinbefore described.
Second-The preparation or production of Insulating materials or articles by
the employment of wood or other vegetable fibrous material as herein set forth in
a finely divided condition desiccated and saturated or impregnated with a mixture
consisting of melted Bitumen or Asphalte incorporated with a substance or
substances of the resin type as herein set forth in conjunction or not with a
substance or substances of the paraffine type or of the Anthracene type or of both
the paraffine and Anthracene types the whole being moulded under pressure
substantially as herein before described.
In witness whereof I the said John Ambrose Fleming have to this my
Specification set my hand and seal this sixteenth day of November One
thousand eight hundred and eighty two.
J. A. FLEMING (L.S.)