AN IMPROVEMENT IN APPLYING HEAT IN THE MANUFACTURE OF ARTIFICIAL GUMS AND TEETH, AND OTHER ARTICLES COMPOSED OF INDIA-RUBBER OF GUTTA PERCHA COMBINED SULPHUR
Year: 1859

page_text: Sealed the 28th June 1859, and dated the 21st January 1859.
PROVISIONAL SPECIFICATION left by the said James Childs at the
Office of the Commissioners of Patents, with his Petition, on the
21st January 1859.
I, JAMES CHILDS, of Windsor House, Windsor Road, Putney, in the County
of Surrey, do hereby declare the nature of the Invention for "AN IMPROVEMENT
IN APPLYING HEAT IN THE MANUFACTURE OF ARTIFICIAL GUMS AND TEETH, AND
OTHER ARTICLES COMPOSED OF INDIA-RUBBER OF GUTTA PERCHA COMBINED
SULPHUR," to be as follows:
This Invention has for its object an improvement in applying heat in the
manufacture of artificial gums and teeth and other articles composed of india-
rubber or gutta percha combined with sulphur. When making artificial gums
and teeth of a composition of india-rubber or gutta percha and sulphur, the
moulded gums or teeth, or a combination of gums and teeth are secured
between plaster of Paris casts or moulds of the mouth they are intended to fit,

page_text: and in this state they are placed in a suitable vessel capable of being exter-
nally heated, and this I prefer to do by gas jets,. though heat may be otherwise
applied. The vessel (which is provided with a man-hole) is in connection with
a steam boiler, so that it can be kept full of steam of low pressure, and such
steam when in the vessel is then further beated up to the high degree of heat
requisite for producing the well known hardening effect consequent on high
temperatures being applied to india-rubber and gutta percha when combined
with sulphur. In like manner, other articles of india-rubber or gutta percha
combined with sulphur may, when held in suitable moulds or forms, be intro-
duced into a vessel; which is then filled with steam and heated externally.
In place of, or in adition to the steam being heated in the vessel in which
the articles are placed, it may, after it leaves the boiler, be heated in its way
to and before getting into the vessel. By thus employing steam of low
pressure, and obtaining the requisite high temperature by surcharging the
steam with heat, the process of "converting " india-rubber and gutta percha
combined with sulphur may be more safely and advantageously carried on.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said James Childs in the Great Seal Patent Office on the 21st
July 1859:
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
CHILDS, of Windsor House, Windsor Road, Putney, in the County of Surrey,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-first day of January, in the year of our Lord
One thousand eight hundred and fifty-nine, in the twenty-second year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said James Childs, Her special licence that I, the said James Childs, my
executors, administrators, and assigns, or such others as I, the said James
Childs, 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 "AN IMPROVEMENT IN APPLYING
HEAT IN THE MANUFACTURE OF ARTIFICIAL GUMS AND TEETH, AND OTHER ARTICLES
COMPOSED OF INDIA-RUBBER OR GUTTA PERCHA COMBINED WITH SULPHUR," upon the
condition (amongst others) that I, the said James Childs, my executors or

page_text: 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 James Childs, do hereby declare the
nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement thereof, that is to say:-
This Invention has for its object an improvement in applying heat in the
manufacture of artificial gums and teeth, and other articles composed of
india-rubber or gutta percha combined with sulphur, and consists in applying
for this purpose superheated steam, that is to say, steam of a higher tem-
perature than is due to its pressure; by thus employing steam of low pressure,
and obtaining the requisite high temperature by surcharging the steam with
heat, the process of converting india-rubber and gutta percha combined with
sulphur may be more safely and advantageously carried on. When making
artificial gums and teeth of a composition of india-rubber or gutta percha and
sulphur, the moulded gums or teeth, or a combination of gums and teeth, are
secured between plaster of Paris casts or moulds of the mouth they are
intended to fit, and in this state they are placed in a suitable vessel capable of
being externally heated, and this I prefer to do by gas jets, though heat may
be otherwise applied. The vessel (which is provided with a man-hole) is in
connection with a steam boiler, so that can be kept full of steam, and such
steam when in the vessel is then further heated up to the high degree of heat
requisite for producing the well known hardening effect consequent on high
temperatures being applied to india-rubber and gutta percha when combined
with sulphur. In like manner, other articles of india-rubber or gutta percha
combined with sulphur may, when held in suitable moulds or forms, be intro-
duced into a vessel, which is then filled with steam and heated externally.
In place of or in addition to the steam being heated in the vessel in which the
articles are placed, it may, after it leaves the boiler, be heated in its way to
and before getting into the vessel.
Having thus stated the nature of my said Invention, I will proceed more
fully-to describe the manner of performing the same. It is well known that
india-rubber and gutta percha, when mixed with sulphur in certain proportions
and subjected to high temperatures, are rendered permanently elastic or con-
verted into hard compounds, and such hard compounds have before been
applied in the manufacture of artificial gums and teeth, and also in the making

page_text: of a great variety of other articles, elastic or non-elastic as required, and
various modes have before been resorted to for applying the heat to such
articles requisite to produce the change which renders such compounds .per-
manently elastic, or into a hard condition resembling horn or bone.
Amongst other methods of applying the requisite temperature to such
compounds, saturated steam of very high pressure has been resorted to, the
use of which is subject to considerable difficulty, and is dangerous. Now,
according to my Invention, I employ steam of comparatively low pressure,
which is, when out of contact with water, heated to the requisite high degree
of temperature known to be necessary for converting articles made of the
'compounds above mentioned into the elastic or the hard or bone, or horn-like
condition as may be required.
The Drawing shows a section of an apparatus suitable for the application of
superheated steam, as above mentioned. a is a boiler or steam generator,
which is supplied with water at the pipe 6 by a pump or other convenient
means; c is a safety valve; d is a steam pipe to supply steam to the vessel e.
The steam boiler is heated by gas jets from a gas supply pipe, on which is a
cock to regulate the heat. The vessel e is also heated by gas jets from the gas
supply pipe, as shown, which has a cock to regulate the quantity of gas passing
to the jets under the vessel e. The vessel or apparatus e is provided with a
tube to contain a thermometer, so that the heat of the interior of the vessel
may be observed and regulated to the degree requisite.. The articles to be
heated (usually contained in suitable moulds) are introduced into the vessel or
apparatus e through the opening e', and they are placed on the false perforated
bottom e², under which the steam pipe from the boiler a is introduced into the
apparatus e, and such pipe is coiled and perforated with numerous small holes.
The opening e' is closed and the cover kept closely shut, as shown, or by other
convenient means; e is a safety valve which I prefer to use, but it is not
essential so long as the one on the boiler acts freely. The under part of the
vessel e being heated as above explained, the steam will become further heated
in this vessel, that is to say, to a temperature exceeding the natural
temperature of the steam in the vessel a. The apparatus e may at its
upper parts and sides be clothed over with non-conducting materials; to
prevent the escape of heat, and such is also the case in respect to the boiler;
is a cock to draw off any water resulting from the condensation of the
steam.
I would remark, that the form or construction of the apparatus e may be
varied, and it may be placed at a greater or less distance from the boiler or
generator which inay be used to supply steam thereto, and the steam may be

page_text: heated as it passes from the boiler or generator, and before passing into the
apparatus e, and in such manner, if desired, as not to require the vessel or
apparatus e to be also heated, but I prefer the arrangement shown in the
Drawing. I would also remark, that although a separate generator may be
employed to ensure that the pressure of the steam should never éxceed that
which is perfectly safe, such separate generator may be dispensed with when
-using superheated steam according to my Invention. When I dispense with
the use of a separate steam generator, then I introduce into the other vessel
about as much water as will, when it is vaporized, fill the vessel with steam of
a pressure such as I wish to employ, and I use a safety valve weighted to the
desired pressure. By these means the vessel, when heat is applied thereto,
will generate steam, and any excess will go off by the safety valve, and the
remaining atmosphere of steam contained in the vessel will then become heated
up to the high degree of heat desired, without so increasing the pressure as to
be liable to injure the vessel.
Figure 2 is a longitudinal section of an apparatus suitable to be used in the
manner above described.
a, a, is an exterior cylinder of wrought iron resting
on feet a', a'; into the top of this cylinder a vessel 6 drops the flange at the
top of this vessel resting on the edge of the cylinder a. The vessel is fur-
nished with a cover, which can be fastened down so as to make a steam-tight
joint; .c is a safety valve, and d a thermometer passing through the top of the
vessel b; e is a gas burner for heating the vessel 6; the supply of gas to the
burner is regulated by suitable taps.
In place of heating the vessel with gas in this manner, other methods of
applying heat may be resorted to, but I prefer gas, as it is most conveniently
applied and regulated. It is preferred to make the vessel 6 of cast iron, as
this material is not liable to be acted on to a prejudicial extent by the sul-
phuretted hydrogen liberated in the converting process. The articles to be
converted, either enclosed in moulds or otherwise according to the nature of
the articles, are placed in the vessel b, together with a small quantity of water,
and the cover is fixed on, and the safety valve weighted to the pressure it is
desired to apply; the gas is then lighted under the vessel b, and steam
generated in the vessel. When the pressure of the steam is sufficient, it raises
the safety valve c, and the steam continues to blow off till all the water is
evaporated; when this is the case the valve closes, and the steam begins to be
superheated. The thermometer should then be carefully observed as the
temperature rises to the desired point, and there it is maintained by regulating
the quantity of gas passing to the burner e by the taps on the gas pipe until
the process is complete. In some cases, in place of putting an indefinite

page_text: quantity of water into the vessel b, and allowing the surplus to blow off by the
safety valve, I only place in the vessel exactly the quantity of water which is
required; thus, if the capacity of the vessel b is one cubic foot, and I desire a
pressure of about 15 lbs. per square inch above atmospheric pressure, I place
two cubic incheses of water in the vessel, and if I desire a pressure of 30 lbs.,
I place three cubic inches of water in the vessel, and so on; the increase of
pressure produced by the heat, after all the water is evaporated, is compa-
ratively small. The pressure of steam in the vessel I prefer to keep at about
ten to twenty pounds on the square inch, or a greater pressure may with
advantage be employed if the articles to be converted are of large size, or a
very hard material be required: this, however, may be varied.
The compositions of india-rubber or gutta percha and sulphur may be such
as have heretofore been employed, and the degree of heat employed, and the
duration of the process will be the same as when saturated steam at a high
pressure is employed, as has been common; the construction of the moulds,
when moulds are employed for containing the articles, will also be as
heretofore.
In witness whereof, I, the said James Childs, have hereunto set my
hand and scal, this Twenty-first day of July, in the year of our Lord
One thousand eight hundred and fifty-nine.