IMPROVEMENTS IN APPARATUS FOR CURING BY HEAT OR VULCANIZING DENTAL PLATES AND OTHER ARTICLES
Year: 1879

page_text: LETTERS PATENT to John Smalley Campbell, of North Plainfield, in the State
of New Jersey, United States of America, for the Invention of "IMPROVEMENTS
IN APPARATUS FOR CURING BY HEAT OR VULCANIZING DENTAL PLATES AND
OTHER ARTICLES.
ور
PROVISIONAL SPECIFICATION left by the said John Smalley Campbell at
the Office of the Commissioners of Patents on the 22nd July 1879.
JOHN SMALLEY CAMPBELL, of North Plainfield, in the State of New Jersey,
United States of America. "IMPROVEMENTS IN APPARATUS FOR CURING BY HEAT
OR VULCANIZING DENTAL PLATES AND OTHER ARTICLES."
Small articles such as dental plates are often made of hard rubber or vulcanite,
or else of pyroxyline, otherwise called celluloid.
This Invention relates to an apparatus wherein the moulds containing teeth and
the rubber or composition can be inserted and cured or vulcanized by heat, with
or without the direct action of steam, at the same time the moulds can be closed or
compressed to the desired extent as the operation progresses.
My Invention consists of two vessels, one within the other, and between which
the water and steam are employed to transmit heat to the contents of the inner
vessel, such steam and water surrounding, or nearly so, the inner vessel for rendering
the temperature uniform, and also for maintaining heat while the steam is shut off
from the vulcanizing vessel, or when the same may be opened for examining the
moulds. I provide a door at one side that can be easily opened or closed, steam
tight, and pressure can be applied to the moulds as the material becomes heated,
a screw passing through the top being employed for this purpose.
A cock is provided for admitting steam from the jacket into the inner vessel, or
shutting off the same.
A thermometer is employed for denoting the temperature, and a cock for drawing
off the steam from the inner vessel before the door is opened. The beat is applied
beneath the outer vessel, preferably by a Bunsen burner.
A safety valve should be provided on the outer vessel.

page_text: By my improvement the moulds can be inspected and pressure applied from time
to time_without_the_moulds_becoming cool; this is of great importance, especially
with dental plates of celluloid, in which it is preferable to soften the rigid material
by steam heat and then to apply the pressure without risk of injury to the moulds,
and after the mould is packed to finish the operation by dry heat, the steam being
excluded from the vulcanizing-vessel.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Smalley Campbell in the Great Seal Patent Office on the
22nd January 1880.
JOHN SMALLEY CAMPBELL, of North Plainfield, in the State of New Jersey,
United States of America. "IMPROVEMENTS IN APPARATUS FOR CURING BY HEAT
OR VULCANIZING DENTAL PLATES AND OTHER ARTICLES."
Small articles such as dental plates are often made of hard rubber or vulcanite, or
else of pyroxyline, otherwise called celluloid.
This Invention relates to an apparatus wherein the molds containing teeth and
the rubber or composition can be inserted and cured or vulcanized by heat, with
or without the direct action of steam, at the same time the molds can be closed or
compressed to the desired extent as the operation progresses.
My Invention consists in two vessels, one within the other, and between which
the water and steam are employed to transmit heat to the contents of the inner
vessel, such steam and water surrounding, or nearly so, the inner vessel for rendering
the temperature uniform, and also for maintaining heat while the steam is shut off
'from the vulcanizing vessel, or when the same may be opened for examining the
molds.
I provide a door at one side that can be easily opened or closed, steam tight,
and pressure can be applied to the molds as the material becomes heated, a screw
passing through-the-top-being-employed for this purpose:
A cock is provided for admitting steam from the jacket into the inner vessel, or
shutting off the same. A thermometer is employed for denoting the temperature,
and a cock for drawing off the steam from the inner vessel before the door is
opened.
The heat is applied beneath the outer vessel, preferably a Bunsen burner.
A safety valve should be provided on the outer vessel.
By my improvement the molds can be inspected and pressure applied from time to
time without the moulds becoming cool; this is of great importance, especially with
dental plates of celluloid, in which it is preferable to soften the rigid material by
steam heat and then to apply the pressure without risk of injury to the molds,
and after the mold is packed to finish the operation by dry heat, the steam being
excluded from the vulcanizing vessel.
In the Drawing,
Fig. 1 is a vertical section of the vulcanizing apparatus, and
1
11

page_text: The internal vessel a is of suitable size for the dental molds, and the outer vessel b
is larger, leaving a sufficient space for water between the two vessels.
It is preferable to cast these two vessels a, b, together, and connect them by
vertical cross plates c between the bottoms. The cover d may also be cast at the
same time with the vessels a, b, there being the necessary space between the top of
the vessel a and said cover d, or else such cover d may be bolted upon the top of
the vessel b. If this cover is movable it is necessary to provide packings at the
joints to make the vulcanizing vessel tight.
The cylindrical portions of the vessels a, b, are united at e, and an opening is
made through the side to obtain access to the inner vessel for introducing or
withdrawing the dental molds, and around the opening there is a projecting rib i,
against which the yielding packing in a groove around the door fis pressed to
make a tight joint when the door is closed.
It is preferable to use the inovable cross-bar h that passes at its ends into grooves
above and below the doorway, and a screw or screws l serves to apply the necessary
pressure to keep the door tight.
When the door is opened it can be turned down level, as shown by dotted lines
in Fig. 1, and held by hooks 2, 2, at its lower corners that act like hinges, the same
as in drop oven doors, so that the door becomes a platform for the molds in entering
or withdrawing the same.
I prefer to introduce glass windows in the doors so that the molds may be
observed without the necessity of opening the door, such glasses being secured in
the door by a clamping frame, or in any suitable manner.
The pressure is applied to the molds by the screw n and follower m, or it may
be done in any other manner; I do not limit myself in this particular.
The screw n is within a tube at the top of the vulcanizing vessel, and there is a
loose follower on its lower end that rests upon the mold. The screw is operated by
a key at the end of a handle taking a square at the end of the screw. The removable
screw cap o is taken off when the screw is to be operated and replaced before steam
is admitted into the inner or vulcanizing chamber to prevent steam escaping around
the screw. The screw may, however, be prolonged as a smooth stem passing
through a packing gland. At s I have shown a thermometer, the same being in
a suitable metal case or plug screwed into the cover of the apparatus, and a
safety valve or fusible plug may also be added to the apparatus.
In order to admit steam into the vulcanizing chamber I employ a valve or cock,
and the same is constructed so as to shut off the steam when it is desired to employ
only a dry heat. In most instances it is preferable to cure or vulcanize the dental
plate in the presence of steam, and then to shut off such steam when the process is
being completed. The tubular valve shown in Fig. 1 has a screw cap or
cock t upon the top, hence it allows steam to pass into the vulcanizing cham-
ber when the valve is unscrewed, and when screwed to its seat the steam is
excluded, and the screw cap or cock t can be opened to allow the steam to pass
out of the vulcanizing chamber.
Having now described the nature of my said Invention, and in what manner the
same is to be performed, I declare that I claim as my Invention,-
First. The combination with a dental vulcanizing vessel of an outer vessel
surrounding, or nearly so, the vulcanizing vessel, so as to obtain uniformity in the
action of the beat, substantially as set forth.
Second. The combination with the vulcanizing vessel a, and exterior vessel b,
of a movable door applied to an opening in the side of the vessels, substantially
as set forth.
Third. In a vulcanizing apparatus a door connected at its bottom edge with the
vessel so as to form a platform when open, in combination with the packing around
the door, and a screw or its equivalent to close the door lightly, substantially as
set forth.

page_text: Fourth. The combination with the vulcanizing vessel a enclosing vessel b and
door-f-of-the-cocks-or-valves, to admit_steam_into_the_vessel.or_exclude_the_same,
substantially as set forth.
-In witness whereof, I, the said John Smalley Campbell, have hereunto set
-my-hand-and¯ seal, this 5th day of November, A.D. 1879.