IMPROVEMENTS IN HARDENING AND VULCANIZING COMPOUNDS OF SULPHUR WITH INDIA-RUBBER AND GUTTA PERCHA
Year: 1859

page_text: LETTERS PATENT to James Childs, of Windsor House, Putney, in the
County of Surrey, for the Invention of "IMPROVEMENTS IN HARDENING
AND VULCANIZING COMPOUNDS OF SULPHUR WITH INDIA-RUBBER AND GUTTA
PERCHA."
Sealed the 27th October 1859, and dated the 18th May 1859.
PROVISIONAL SPECIFICATION left by the said James Childs at the
Office of the Commissioners of Patents, with his Petition, on the
18th May 1859.
I, JAMES CHILDS, of Windsor House, Putney, in the County of Surrey, do.
hereby declare the nature of the Invention for "IMPROVEMENTS IN HARDENING
AND VULCANIZING COMPOUNDS OF SULPHUR WITH INDIA-RUBBER AND GUTTA PERCHA,"
to be as follows:-
This Invention has for its object improvements in hardening and vulcanizing
compounds of sulphur with india-rubber and gutta percha. Heretofore such
compounds have been hardened and vulcanized by several different processes.
In some cases the compound, either enclosed in a mould of plaster of Paris,
or otherwise, has been placed in an oven and exposed to a temperature
sufficient to produce the change required; this process does not, however,
succeed very well in practice, as articles manufactured in this manner are
liable to be porous. In some cases to overcome this difficulty, the compound
has been placed in a steam boiler or chamber in which the steam is maintained
at such a pressure that its temperature shall be sufficiently high to produce

page_text: the desired result. To avoid the risk and inconvenience arising from the use
of a high-pressure boiler, I have myself employed superheated steam to
produce the hardening or vulcanizing change under a Patent granted to me
and dated January 21st, 1859.
My present Invention consists in placing articles formed of india-rubber
and gutta percha compounded with sulphur in a close vessel together with a
hydrated substance, such as gypsum or lime, but without free water, and then
exposing the vessel and its contents to a sufficient heat to produce the change
required in the compound. The hydrated substance during the process
generates steam sufficient to maintain an atmosphere of steam in the close
vessel, but will not under any ordinary heat generate so much steam as to
endanger the safety of the vessel.
In practice I find it convenient to mould the compound of india-rubber or
gutta percha 'with sulphur in a shape or mould made of plaster of Paris, which
plaster of Paris will during the hardening or vulcanizing process yield the
quantity of steam required.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said James Childs in the Great Seal Patent Office on the
16th November 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
CHILDS, of Windsor House, Putney, in the County of Surrey, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighteenth day of May, 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 "IMPROVEMENTS IN HARDENING AND VULCANIZING
COMPOUNDS OF SULPHUR WITH INDIA-RUBBER AND GUTTA PERCHA," upon the con-
dition (amongst others) that I, the said James Childs, my executors or
administrators, by an instrument in writing under my, or their, or one of
heir hands and seals, should particularly describe and ascertain the nature of

page_text: 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
performed, to be particularly described and ascertained in and by the following
statement thereof, that is to say:-
This Invention has for its object improvements in hardening and vulcanizing
compounds of sulphur with india-rubber and gutta percha. Heretofore such
compounds have been hardened and vulcanized by several different processes.
In some cases the compound, either enclosed in a mould of plaster of Paris or,
otherwise, has been placed in an oven and exposed to a temperature sufficient
to produce the change required; this process does not, however, succeed very
well in practice, as articles manufactured in this manner are liable to be
porous. In some cases to overcome this difficulty the compound has been
placed in a steam boiler or chamber, in which the steam is maintained at such.
a pressure that its temperature shall be sufficiently high to produce the
desired result. To avoid the risk and inconvenience arising from the use of a
high-pressure boiler, I have myself employed superheated steam to produce.
the hardening or vulcanizing change under a Patent granted to me, and dated.
the 21st January, 1859.
My present Invention consists in placing articles formed of india-rubber and
gutta percha compounded with sulphur in a close vessel, together with a
bydrated substance, such as gypsum or lime, but without free water, and then.
exposing the vessel and its contents to a sufficient heat to produce the change
required in the compound. The hydrated substance during the process
generates steam sufficient to maintain an atmosphere of steam in the close
vessel, but will not under any ordinary heat generate so much steam as to
endanger the safety of the vessel.
In practice I find it convenient to mould the compound of india-rubber or.
gutta percha with sulphur, and the coloring or other admixtures in a shape or
mould made of plaster of Paris, which plaster of Paris will during the
hardening or vulcanizing process yield the quantity of steam required.
Figure 1 is a vertical section of an apparatus such as I prefer to employ in
carrying my Invention into effect. a, a, is a vessel, by preference of cast iron,
and 6 is the cover of the same; it is attached to the upper flange of the
vessel a by screws c, c, but can be readily removed when required for the
introduction and withdrawal of the materials. d is a case, containing a
thermometer for indicating the temperature within the vessel a; e, e, are ring

page_text: gas burners; f is a hollow plug, screwed into the cover b; this plug is shown
separately at Figure 2; it is filled interiorly with fusible metal, ordinarily a
mixture of tin. and lead, melting at about 350° Fahrenheit, and thus all danger
is avoided, for should the temperature be allowed to rise to a much higher
degree than can ever be required in the process, the fusible metal melts and
relieves the pressure within the vessel. I have found in practice that for a
vessel of the capacity of a cubic foot a lump of air-dried plaster of Paris,
containing about 18 cubic inches, is sufficient to, produce the steam required in
the process, and if a mould of plaster of Paris be employed for containing the
compounds of sulphur with india-rubber or gutta percha, it will generally
contain sufficient plaster for the purpose; if metal or other moulds be
employed, then a lump of plaster of Paris of the required size should be
placed in the vessel with the moulds. In some cases I employ in place of
plaster of Paris a similar quantity of slaked lime, and other matters with
which water is combined may be employed, if preferred. In conducting the
hardening or vulcanizing process, I regulate the heat by means of the taps
connected with the gas burners; the degree of heat employed; and the
length of time during which it is maintained, being regulated according to the
nature of the article to be produced, as is well understood. When the plaster
of Paris or other substance becomes heated, it evolves steam, which, as the
heat is continued, becomes superheated, for the pressure of the steam within
the vessel never rises so high as it would do if the vessel contained water in a
liquid state; this arises from the water being retained with considerable force
by the plaster.
In witness whereof, I, the said James Childs, have hereunto set my
hand and seal, this Fifteenth day of October, in the year of our Lord
One thousand eight hundred and fifty-nine.
JAS. CHILDS. (L.S.)