Improvements in Air Tight Cans for Preserved Food and other substances.
Year: 1892

page_text: Date of Application, 11th Apr., 1892-Accepted, 21st May, 1892
COMPLETE SPECIFICATION.
Improvements in Air Tight Cans for Preserved Food and other
substances.
I, SALO ZADEK, of Zimmerstrasse 25, Berlin, in the Empire of Germany,
Builder, do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by
the following statement:-
This invention relates to closed vessels such as vessels containing edible or other
preserved substances or liquids.
According to this invention there is employed a plug, strip or stopping piece and
fusible-sealing material, such as resin, mineral wax, or like substance, said material
being laid over the stopping piece of the vessel, either before or after the usual
heating or boiling so that when heated the said fusible sealing material softens or
liquefies and closes such opening part, either before reaching the boiling point, at
the boiling point, or after.
In order to prevent the suction into the vessel of this sealing material after the
condensation of the vapours given off from the contents of the vessel, the vessels
are made of special shapes and, respectively, special kinds of closing parts are
provided as hereafter set forth.
The annexed drawings shew in Figures 1 and 2 two forms of vessels in which the
lids are made tight by means of an india rubber ring a.
In the example shewn in Figure 1, the vent opening of the vessel is shaped
like a tapered funnel having a stopper or cone c which fits in the funnel. The said
cone is covered with the fusible sealing material such as resin, or mineral wax, and
produces an air tight seal or joint when it is pressed down by the pressure of the
atmosphere owing to the partial vacuum in the vessel. Any slight imperfections
in the sealing are filled in by the fusible sealing material.
The opening in the vessel may consist of a simple indent and perforation d in the
lid of the vessel, as shewn at Figure 2, in which case the air tight seal is produced
by laying a small piece of tin or other material e covered with the fusible material
in the indent, and the part e is pressed against the lid when a vacuum is formed in
the vessel; the seal is made good by the fusible material.
In order to ensure the
perfect scaling of this part e, a weight can be laid on the plate e so as to form a
weighted vent hole cover.
In order to ensure an even heating of the contents of the vessel and thereby a
perfect sealing due to the vapours having been driven off, there is attached to the
lid of the vessel a cylindrical part g, open at the top and closed at the bottom,
which reaches to the bottom of vessel and fits into an indent which holds it in its
place and prevents the rubber fastening of the lid being loosened.
The fusible sealing material can be stiffened with chalk or like material, should
it be too liquid, so as to make the suction of it into the interior of the vessel
impossible.
During the cooking process all the vapours escape through the vent, and this
action continues throughout the whole of the cooking operation. As soon as the
cooking heat ceases, a decrease of the temperature inside of the vessel, and a
consequent condensation of the vapours, takes place, and the lid is forced down, the
lid and the closing parts, namely, the small piece of tin e or cone c, by means of the
fusible sealing material produce an airtight sealing. After cooling and hardening
the fusible sealing material provides a seal.
By means of this invention, which acts entirely automatically, there is a saving
in time and labour, besides affording a particularly effective sealing, by which any
chance defect, such as might occur in soldering, becomes impossible. It also makes

page_text: a much cheaper material available than the costly tin solder, as resin, mineral fats,
and such like compositions may be used.
Also a great advantage is gained by its being possible to effect the sealing at a
certain degree of heat, since the sealing material according to its composition
melts at a certain fixed temperature, and by this means the moment of sealing, or
say the degree of heat at which the sealing takes place, can be determined in
advance.
any extra
Should the cooking be repeated after the sealing has taken place, then
pressure of the vapours inside the vessel escapes through the vent hole the cover of
which is raised through the fusible sealing material.
Vessels which have been sealed according to this invention, do not require
cutting to open them: they admit of being opened with ease, by means of an
ordinary knife, and by heating the sealing material, preventing thereby damage to
either vessel or lid, which may both be again used.
Hitherto preserving tins have been more or less soldered on. The cost of this is
considerable and the sealing is often not tight, causing the contents frequently to get
spoiled. To open such tins a special cutting contrivance is always necessary, such
as a can opener, the application of which not unfrequently not only spoils the
contents of the tin but also renders the tin unavailable for subsequent use.
With this invention any number of tins can be subjected to the cooking or boiling
process at the same time, and when the cooking is done they are all closed and
sealed automatically. The tins also open automatically when they are placed in
boiling water or over the fire. They can also be opened with an ordinary pocket
knife.
The tins close entirely to the exclusion of the outer air, since the closing devices,
the cone c, or plate e, act as a non-return valve. It is therefore no longer necessary
to use the whole of the contents if the vessel after being opened, as the tins can, by
reheating, be again closed and the remainder of the contents preserved.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-
1. Effecting the closing and sealing of vessels, containing edible or other
substances, by a plug, strip, or stopping piece, arranged in connection with the
vessel and adapted to operate, substantially as and for the purposes described.
2. The means substantially as herein described of evenly heating the contents of
tins or vessels containing edible or other substances, which means consist of a
cylinder attached to the lid of and fitting into an indent in the bottom of the
vessel, whereby the closing is assisted as set forth.
3. The means of closing vessels substantially as herein described and as shewn in
the annexed drawings.
Dated this 9th day of Anvil 1809
CHEESBROUGH & ROYSTON, Fels. Chart. Inst. P.A.,
15, Water Street, Liverpool, Applicant's Agents.