IMPROVEMENTS IN TREATING AND PREPARING GUTTA PERCHA AND OTHER LIKE SUBSTANCES, AND IN MACHINERY USED IN THE PREPARING PROCESS
Year: 1870

page_text: LETTERS PATENT to Edwin Thomas Truman, of Old Burlington Street,
in the County of Middlesex, for the Invention of "IMPROVEMENTS IN
TREATING AND PREPARING GUTTA PERCHA AND OTHER LIKE SUBSTANCES, AND
IN MACHINERY USED IN THE PREPARING PROCESS."
Sealed the 15th September 1870, and dated the 25th March 1.870.
PROVISIONAL SPECIFICATION left by the said Edwin Thomas Truman
at the Office of the Commissioners of Patents, with his Petition,
on the 25th March 1870.
I, EDWIN THOMAS TRUMAN, of Old Burlington Street, in the County
of Middlesex, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN TREATING AND PREPARING GUTTA PERCHA AND OTHER LIKE
SUBSTANCES, AND IN MACHINERY USED IN THE PREPARING PROCESS," to be as
follows:-
It has been heretofore usual to place gutta percha and other similar
substances after they have been cleansed in the machine known as the
masticating machine for the purpose of kneading it into a homogeneous

page_text: mass fit for manufacturing purposes. This process has the effect of
softening the gum, and if continued for a long time so as to render the
material homogeneous it effects that result at a sacrifice of cohesive
strength in the prepared material.
My present improvements relate to an improved method of treating t
the cleansed gutta percha, which is usually produced in a spongy or
porous state, the pores being filled with the water employed in cleansing
the gum from impurities, and my object is to desiccate and con-
solidate the cleansed gum so as to prepare it and render it by my
improved finishing process fit to be immediately used for manufacturing 1
purposes.
In the ordinary process of cleansing gutta percha it has become usual
to adopt the plan of kneading in hot water as patented by me on the
25th August 1860, No. 2052. I have recently succeeded in perfecting
a much more efficient process of cleansing gutta percha and other gums 1
by the aid of improved machinery, being an Invention for which I
applied for Letters Patent on the 5th January 1870, No. 41. That
improved method of cleansing raw or crude gutta percha I much prefer
as a first preparatory process; but my improved finishing process
employed as herein-after described is also applicable to gutta percha or 2
other gums when cleansed by the ordinary cleansing processes hitherto
used.
I will now procced to describe the way in which I employ my
improved finishing process by desiccating and consolidating the
cleansed gutta percha, which I will assume to have been cleansed by 2
my improved method, the subject of my said application for Patent
of 5th January 1870. The said cleansing operation having been
rapidly performed, leaves the gutta percha a more or less spongy
mass, cleansed, but saturated to a great extent with moisture. Any
convenient method of cleansing may be used, and in some instances 3
materials that are when imported comparatively free from dirt can be
used for some purposes without cleansing, but in these cases the material
should be made homogeneous to the required degree, and this can be
advantageously done by my new method herein-after described.
I place the material when cleansed, if it requires cleansing, in a 3
machine consisting of a cylindrical metal case, in which works a screw
of (by preference) three blades, or having three threads deeply cut. The

page_text: case has on the top of it a large open hopper, and it has also an exit
opening at one end, towards which the material is forced by the action
of the screw in the act of rotation, as is well understood. To this
opening I attach a bent tube or tubular channel so arranged as to
conduct the material forced into and along it back into the hopper, and
so deliver it again to the action of the forcing screw. The tube or
channel I make of metal or other suitable heat resisting material.
The terminals of the threads of the forcing screw are so constructed as
to press closely by their edge over the exit opening leading into the
tube, and each terminal therefore forces at each rotation a portion of
gum into the tube, and in so doing it cuts into the spongy mass of the
cleansed gum, and liberates a portion of gas, air, or liquid, which is
squeezed out and escapes from the pores of the mass, and the slice cut
is pressed upon and united with the preceding portion already forced
into the tube.
The operation of forcing the material through the case by the forcing
screw which slices successive portions and pushes them through the
tubular channel and delivers them back through the hopper into the
case is repeated over and over again; the number of times will depend
upon the state and quality of the cleansed gum operated upon, and can
be readily determined by an experienced workman. In the early part
of the operation I cause the tube to be highly heated by applying heat
externally to part or to the entire length of the channel, and I prefer
the former, the result being that the moisture contained in the pores of
the gum is converted into steam and is ready to be liberated directly the
gutta percha reaches the opening of the tube leading back into the case.
The partially desiccated gutta percha is then again operated upon in the
machine and pressed out as before. I continue the application of heat
(taking care that it shall be high enough to drive off moisture in the
shape of steam, but not so high as to injure the gum operated upon)
until all or nearly all the moisture is driven off. I then withdraw the
application of heat and continue the operation with the tube cool until
all the air and gas contained in the gum is found to be driven off, and
the gutta percha passes out of the tube desiccated and consolidated as a
dense, close, homogeneous, and more or less transparent gum in a state
fit for being immediately used as an insulator for telegraph wires, or for
other manufacturing purposes.

page_text: I have described my improved finishing process as carried on by
repeated action in the same machine; but similar results may be
obtained by substantially similar means, if several or a series of screw-
forcing machines be employed, and the gum operated upon is passed
from one machine to another through connecting tubular channels. In
such a series of machines heat should be applied to the channels used
between the machines in the first part of the operation in a manner
analogous to that above described, and the latter part of the operation
should be conducted without the application of heat to the connecting
channels, so as to produce the gum when ejected from the last machine
of the series in an efficiently desiccated and consolidated state.
Or the process may be in some cases performed in two distinct
operations, two separate machines being used, and the material in
that case may be conveyed by hand or otherwise from one machine to
another.
As an insulator for deep sca cables, gutta percha treated and prepared
by my improved finishing process has many advantages:-1st, it is a
better insulator; 2nd, it has less inductive capacity, because without
excessive kneading or mastication I obtain a finished gum more com-
pletely desiccated and consolidated than has hitherto been practicable
by the means hitherto used. Again I obtain a superior dry, dense,
almost transparent gum more economically by my improved process and
machinery, and a far superior gum than would have been obtained by
the old process, because I effect the operation in about one-third of the
time occupied by the old processes, the longer process being to the
detriment of the material, and the injury being aggravated in proportion
to the length of time for which the operation was continued.
In my improved finishing process the steam generated by driving out
the moisture contained in the pores of the cleansed gutta percha protects
the gum from injury, and also improves its quality. The proper amount
of heat that should be applied and the length of time for which the
continued operation above described should be kept up must depend on
the quality of the crude material, as was above stated, and this will be
well understood by any one accustomed to operations of an analogous
character in preparing or working gutta percha or india-rubber or
other like gums.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Edwin Thomas Truman in the Great Seal Patent
Office on the 22nd September 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWIN
THOMAS TRUMAN, of Old Burlington Street, in the County of Mid-
dlesex, send grecting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-fifth day of March, in the year
of our Lord One thousand eight hundred and seventy, in the thirty-
third year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Edwin Thomas Truman, Her special licence
that I, the said Edwin Thomas Truman, my executors, administrators,
and assigns, or such others as I, the said Edwin Thomas Truman, my
executors, administrators, and assigns, should at any time agree with,
and no others, from time to time and at all times thereafter during the
term therein expressed, should and lawfully might make, use, exercise,
and vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
TREATING AND PREPARING GUTTA PERCHA AND OTHER LIKE SUBSTANCES, AND IN
MACHINERY USED IN THE PREPARING PROCESS," upon the condition (amongst
others) that I, the said Edwin Thomas Truman, my executors or
administrators, by an instrument in writing under my, or their, or
one of their hands and seals, should particularly describe and ascertain
the nature of the said Invention, and in what manner the same was
to be performed, and cause the same to be filed in the Great Seal
Patent Office within six calendar months next and immediately after
the date of the said Letters Patent.
NOW KNOW YE, that I, the said Edwin Thomas Truman, do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement thereof, that is to say:—
It has been heretofore usual to place gutta percha and other similar
substances after they have been cleansed in the machine known as the
masticating machine for the purpose of kneading them into a homo-
geneous mass fit for manufacturing purposes. This process has the effect
of softening the gum, and if continued for a long time so as to render

page_text: the material homogeneous it effects that result at a sacrifice of cohesive
strength in the prepared material.
My present improvements relate to an improved method of treating
the cleansed gutta percha, which is usually produced in a spongy or
porous state, the pores being filled with the water employed in cleansing
the gum from impurities, and my object is to desiccate and con-
solidate the cleansed gum so as to prepare it and render it by my
improved finishing process fit to be immediately used for manufacturing
purposes.
In the ordinary process of cleansing gutta percha it has become usual
to adopt the plan of kneading it in hot water as patented by me on the
25th day of August 1860, No. 2052. I have recently succeeded in
perfecting a much more efficient process of cleansing gutta percha and
other gums by the aid of improved machinery, being an Invention for
which I applied for and obtained Letters Patent dated the 5th day of
January 1870, No. 41. That improved method of cleansing raw or
crude gut'a percha I much prefer as a first preparatory process; but my
improved finishing process employed as herein-after described is also
applicable to gutta percha or other gums when cleansed by the ordinary
cleansing processes hitherto used.
I will now proceed to describe the way in which I employ my
improved finishing process by desiccating and consolidating the cleansed
gutta percha, which I will assume to have been cleansed by my
improved method, the subject of my said application for Patent of
5th January 1870. Any convenient method of cleansing may however
be used, and in some instances materials that are when imported
comparatively free from dirt can be used for some purposes without
cleansing, but in these cases the material should be made homogeneous
to the required degree, and this can be advantageously done by my new
method herein-after described. The said cleansing operation having
been as I prefer rapidly performed, leaves the gutta percha a more
or less spongy mass cleansed but saturated to a great extent with
moisture.
I place the material when cleansed, if it requires cleansing, in a
machine consisting of a cylindrical metal case, in which works a screw
having (by preference) three blades, or having threo threads deeply cut.
The case has on the top of it a large open hopper, and it has also an

page_text: exit opening at one end, towards which the material is forced by the
action of the screw in the act of rotation, as is well understood. To this
opening I attach a bent tube or tubular channel so arranged as to
conduct the material forced into and along it back into the hopper, and
so to deliver it again to the action of the forcing screw. The tube or
channel I make of metal or other suitable heat resisting material.
The terminals of the threads of the forcing screw are so constructed
as to press closely by their edge over the exit opening leading into the
tube, and cach terminal therefore forces at each rotation a portion of
gum into the tube, and in so doing it cuts into the spongy mass of the
cleansed gum, and liberates a portion of gas, air, or liquid, which is
squeezed out and escapes from the pores of the mass, and the slice cut
off is pressed upon and united with the preceding portion already forced
into the tube.
The operation of forcing the material through the case by the forcing
screw which slices successive portions and pushes them through the
tubular channel and delivers them back through the hopper into the
case is repeated over and over again; the number of times will depend
upon the state and quality of the cleansed gum operated upon, and can
be readily determined by an experienced workman. In the early part
of the operation I cause the tube or case to be highly heated by applying
heat externally to part or to the entire length of the channel, and I
prefer the former, the result being that the moisture contained in the
pores of the gum is converted into steam and is ready to be liberated
directly the gutta percha reaches the opening of the tube leading
back into the casc. The partially desiccated gutta percha is then
again operated upon in the machine and pressed out as before.
I continue the application of heat (taking care that it shall be high
enough to drive off moisture in the shape of steam, but not so high as to
injure the gum operated upon) until all or nearly all the moisture is
driven off. I then withdraw the application of heat and continue the
operation with the tube cool until all the air and gas contained in the
gum are found to be driven off, and the gutta percha passes out of
the tube desiccated and consolidated as a dense, close, homogeneous,
and more or less transparent gum in a state fit for being immediately
used as an insulator for telegraph wires, or for other manufacturing
purposes.

page_text: I have described my improved finishing process as carried ou by
repeated actions in the same machine; but similar results may be
obtained by substantially similar means if several or a series of screw-
forcing machines be employed, and the gum operated upon is passed
from one machine to another through connecting tubular channels. In
such a series of machines heat should be applied to the channels used
between the machines in the first part of the operation in a manner
analogous to that above described, and the latter part of the operation
should be conducted without the application of heat to the connecting
channels so as to produce the gum when ejected from the last machine
of the series in an efficiently desiccated and consolidated state.
Or the process may be in some cases performed in two distinct
operations, two separate machines being used, and the material in
that case may be conveyed by hand or otherwise from one machine to
another.
As an insulator for deep sea cables, gutta percha treated and prepared
by my improved finishing process has many advantages:-1st, it is a
better insulator; 2nd, it has less inductive capacity, because without
excessive kneading or mastication I obtain a finished gum more com-
pletely desiccated and consolidated than has hitherto been practicable
by the means hitherto used. Again, I obtain a superior, dry, dense,
almost transparent gum more economically by my improved process and
machinery, and compared with that which is ordinarily obtained by the
old process. I effect the operation in about one-third of the time
occupied by the old processes, the longer process being to the detriment
of the material, and the injury being aggravated in the old process in
proportion to the length of time for which the operation is continued.
In my improved finishing process the steam generated by driving out
the moisture contained in the pores of the cleansed gutta percha protects
the gum from injury and also improves its quality. The proper amount
of heat that should be applied, and the length of time for which the
continued operation above described should be kept up must depend
on the quality of the crude material as was above stated, and this will
be well understood by any one accustomed to operations of an analogous
character in preparing or working gutta percha or india-rubber or
other like gums.

page_text: Having now described my Invention and the manner in which it is
performed, I claim,—
First. The application of my improved finishing process applied in the
manner and for the purpose substantially as herein-before described to
the preparation of gutta percha and other analogous gums.
Second. The combination of parts forming my improved apparatus
constructed and employed substantially in the manner herein-before..
described for the purpose of treating and preparing gutta percha and
other analogous gums.
In witness whereof, I, the said Edwin Thomas Truman, have here-
unto set my hand and seal, this Twentieth day of September
One thousand eight hundred and seventy.
EDWIN THOS. TRUMAN. (L.S.)