New INSULATING COMPOUNDS FOR ELECTRICAL PURPOSES
Year: 1884

page_text: I ALEXANDER MUIRHEAD of N° 3 Elm Court Temple in the City of London
Electrical Engineer do hereby declare the nature of my Invention for New
INSULATING COMPOUNDS FOR ELECTRICAL PURPOSES to be as follows:-
According to this invention the new compounds I wish to introduce for electrical
purposes are made by combining gutta-percha with the substitution products which
result from the action of chloride of sulphur or other similar re-agent upon any of
the family of what are known as glycerides in organic chemistry.
In carrying out this invention the glyceride I prefer to use is stearine-one
which can be obtained very pure in commerce-A quantity of stearine dissolved in
bisulphide of carbon or other solvent is taken and subjected to the action of either
fumes of chloride of sulphur or a solution of chloride of sulphur in either paraffin
oil or in a mixture of paraffin oil and bisulphide of carbon, with the assistance of
agitation.
The resulting elastic compound is carefully washed and then combined by means
of hot mixing rollers with a quantity of gutta-percha which has been prepared in
the ordinary way.
I do not wish to limit this invention to the use of stearine. Any of the pure
liquid glycerides extracted from various oils-such as linseed oil, animal fats &C.-
will do to form the elastic compound required for admixture with gutta-percba but
I prefer to use that obtained from the solid glyceride stearine on account of its
higher insulating property.
I am aware that it is not new to mix with gutta-percha various oxidized or
sulphurized oils which originally contained glycerides along with other compounds
but I believe it is new to use pure glycerides in the manufacture of an elastic
compound for electrical purposes.
The compounds formed by using pure glycerides alone in the manner above
described I find are superior in insulation resistance to those formed by the similar
treatment of oils and fats containing glycerides together with other bodies.
TY
001
1001

page_text: I ALEXANDER MUIRHEAD of No 3 Elm Court, Temple E.C. in the City of London
Telegraph Engineer do hereby declare the nature of my Invention for NEW
INSULATING COMPOUNDS FOR ELECTRICAL PURPOSES and in what manner the
same is to be performed, to be particularly described and ascertained in and by
the following statement:-
In the Specification of Letters Patent No 5835 of 1883 granted to me I described
the formation of an elastic substance produced by the action of chloride of sulphur
upon such bodies as linseed oil, castor oil, fats &c., and I also described a new mode
of manufacture of compounds suitable for electrical insulating purposes composed of
mixtures of this elastic body with gutta-percha in various proportions. Since the
date of the above patent I have found that these mixtures of gutta-percha with the
elastic compound made from the oils just as they occur in commerce deteriorate in
time through the action, I suspect, of certain nitrogenized matter which was present
originally in the oils.
Now the object of this invention is to produce a purer and more lasting compound,
and in carrying it out I-when linseed or castor oil is employed-free the oil from
all impurities before submitting the same to the action of chloride of sulphur, the
only ingredients of the oils essential to the formation of the elastic compound being
the glycerides. To effect this I thoroughly exhaust the impure oil in boiling water
and then treat it in the cold with a weak alkaline solution in the way ordinarily
adopted in the purification of rancid oils and fats. A mixture of pure glycerides is
thus obtained. I sometimes employ solid glycerides such as stearine, palmitin, or
olein either singly or in combination with each other. These solid glycerides can
now be obtained in a very pure state commercially.
A quantity of stearine dissolved in bi-sulphide of carbon or other solvent is taken
and subjected to the to the action of either fumes of chloride of sulphur or a
solution of chloride of sulphur in either paraffin oil or in a mixture of paraffin oil
and bi-sulphide of carbon, with the assistance of agitation, when an elastic compound
results similar to that produced from the liquid glycerides contained in linseed,
castor, and other oils.
. I do not wish to limit this part of the invention to the use of solid glycerides like
stearine or palmitin. Any of the pure liquid glycerides extracted from the various
oils such as linseed and castor oils, in the manner above described will do to form
the elastic compound required for admixture with gutta-percha but I prefer to use
that obtained from the pure solid glycerides stearine, palmitin &c., on account of
their higher insulating property.
I am aware that it is not new to mix with gutta-percha various oxidized or
sulphurized products from oils which originally contained glycerides along with
nitrogenized impurities in the manufacture of an elastic and plastic compound for
electrical purposes. The compounds formed by using pure glycerides whether solid
or liquid at the ordinary temperature alone in the manner above described I find
are superior in insulation resistance to those formed by the similar treatment of
impure oils and fats containing glycerides together with other bodies.

page_text: Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed I declare that what
I claim is
1. The compound to be used for electrical purposes which consists of a mixture
of gutta-percha with the elastic body prepared by subjecting pure glycerides, liquid
or solid, to the action of chloride of sulphur, substantially as described.
2. The use of stearine and other pure glycerides in the manufacture of elastic
products formed by the action of chloride of sulphur upon such bodies as described.
3. In the manufacture of the elastic substance required for admixture with gutta-
percha to form new insulating compounds for electrical purposes, purifying the oils
before subjecting them to the action of chloride of sulphur substantially as described.
שי.
1007
ALEX. MUIRHEAD..