An Improvement in Hermetically Sealing Tins and other Receptacles for Alimentary and other Substances.
Year: 1899

page_text: Date of Application, 22nd Sept., 1899
Complete Specification Left, 22nd June, 1900-Accepted, 22nd Oct., 1900
An Improvement in Hermetically Sealing Tins and other Receptacles
for Alimentary and other Substances.
I, JOHN RADCLIFFE CROFT, of 20, Mark Lane, in the City of London, Merchant,
do hereby declare the nature of this invention to be as follows:-
'
My invention relates to hermetically closing tins or cans and other receptacles
for alimentary and other substances and it has for its object to provide means
whereby to obviate the difficulty which has heretofore been experienced in sealing
up such receptacles after the internal air has been expelled and before the external
air can re-enter and which is apt to lead either to the over-cooking of the con-
tents of the tin or can or the inefficiency of the operation owing to defective
exhaustion of the air.
In the ordinary method of canning, a pinhole is left for the exit of the air
which is forced out by heating the can in a bath. This pinhole is subsequently
closed with solder in order to seal the can hermetically but the operation of
soldering requires skill and is in any case a delicate one subject to considerable
difficulty, owing to the fact that the exact moment for sealing the pinhole must
be seized, that is to say the soldering must be effected the instant the pressure
from within the can ceases.
According to my invention I avoid this difficulty by providing the tin or other
receptacle with a stopper (applied either to the top or side of the tin or other
receptacle) having an orifice into which a plug may be smartly driven to close
the orifice at the required instant, this being possible notwithstanding any con-
tinuance of internal pressure which, although sufficient to prevent the closure of
the orifice by soldering does not prevent the driving in of the plug, which may
afterwards be sealed over if desired so as to prevent liability of displacement, or
in course of time being permeated by either internal or external gases.
Dated this 22nd day of September 1899.
An Improvement in Hermetically Sealing Tins and other Receptacles
for Alimentary and other Substances.
I, JOIN RADCLIFFE CROFT, of 20, Mark Lane, in the City of London, Merchant,
do hereby declare the nature of this invention and in what manner the same is

page_text: to be performed to be particularly described and ascertained in and by the
following statement:-
My invention relates to hermetically closing tins or other receptacles for
alimentary substances which are preserved by heating or boiling in their own
juices or in water, and it consists of a method of and means for, effecting the
sealing, after the complete expulsion of the contained air and before any air can
re-enter.
In the ordinary method of sealing tins the air is expelled (by the steam
generated within the vessel by heat) through a pinhole which is subsequently
closed with solder. The operation of scaling the pinhole must, to be effectual
be performed at the exact instant when the internal pressure ceases because if
the solder be applied before the pressure ceases the steam will blow through the
liquid solder and leave a hole therein, and if the solder be applied after the
pressure has ceased for however short a time, some air will have entered which
unless sterilized will be sufficient to cause the subsequent putrefactive decom-
position of the contents. As it is impossible to seal the pinhole with liquid
solder before the pressure ceases, and as in practical working it is equally im
possible to seal a large number of vessels at the exact moment when pressure
ceases in each, recourse is had to reheating the contents after sealing, in order
to sterilize the air that may have entered, and this reheating necessarily causes
such overcooking of the contents as to materially impair the texture, appearance
and flavour of the food which it is an especial object of my invention to avoid,
whilst ensuring perfect preservation for an indefinite period.
According to my invention I overcome the difficulty by a method and means
of preliminary or ad interim sealing which is performed after the air has been
expelled, but before the internal steam pressure has ceased, and consequently
before any air whatever can have re-entered, said sealing affording a hermetic
closure until the final scaling (which may be performed at leisure) which con-
stitutes a permanent hermetic closure.
For the purposes of my invention I provide an escape orifice in the receptacle
and a plug for closing the same, the escape orifice being adapted to receive,
and to be hermetically closed by the plug when the same is driven in.
According to the method of my invention this is done whilst steam is still issuing
it being possible to drive in the plug notwithstanding the continuance of internal
steam pressure and by this means to close the orifice so tightly as to prevent
the re-entry of any air when by the cooling of the vessel pending the applica-
tion of the final seal, a vacuum is formed within the vessel. The orifice is pre-
ferably formed in a bush seated or fitted in the top of the receptacle or in the
cover or stopper by which the mouth of the receptacle is closed, but the bush
might be omitted and the plug be driven directly into a seat in the top cover
or stopper.
The final sealing is performed by applying a covering of impermeable material
so as to ensure a permanent hermetic closure.
Reference is to be had to the accompanying drawings forming part of this
specification wherein I have illustrated the invention on a magnified scale.
Figure 1 shews a central section of the means of initially sealing a tin, the
plug not yet having been driven in. Figure 2 shows the plug driven in and the
whole finally sealed. Figures 3 and 4 show a modification in which the bush is
omitted. Figure 5 shows the application of the invention to a cork or bung
for closing a wide mouthed bottle or jar, and Figure 6 shows the same applied to
an ordinary bottle cork.
In Figures 1 and 2, A is the bush 'preferably of slightly conical form, tightly
fitted in a corresponding seat B formed by a tube soldered at 6 into an aperture
in the cover C of the tin, the tube B being preferably slightly conical and
seamless. The said bush A has a through orifice D for the escape of the air
during the heating, this orifice being closed by a plug E which is preferably

page_text: of slightly tapered form and is driven tightly into the orifice D at the proper
moment. Instead of using an apertured bush the plug E might fit directly into
the seat B as in Figures 3 and 4.
In either case the cover C is supposed to have been previously soldered at c
over the mouth in the top of the tin after the latter has been filled with the
food to be preserved, but instead of the seat B being carried by a cover C the
latter might be the top of the tin itself.
In Figure 5C is the cork bung (closing a wide mouthed bottle or jar) in
which a hole is punched to form a seat into which a bush A of conical form is
driven tightly, and in Figure 6 C is an ordinary bottle cork through which a
hole is punched to receive a long bush A which need not in this case be conical,
the bush in either case having an orifice D which is closed by a plug E driven
in as before described. The bush A and plug E may both be made of wood and
to ensure a tight joint the bush A after being driven into its seat should be
boiled in water before use, so as to swell the bush and expel any contained air
from the wood and also from the cork in the case of Figures 5 and 6.
The final sealing is effected by applying a covering layer of impermeable
material such as paraffin wax, or (in the case of a tin) melted solder, which is
run into a recess left for its reception by slightly countersinking the bush into
its seat as in Figure 2 where I represents the wax or solder. The wax or the
solder fills up the recess above the bush and plug and adheres to the sides 6 of the
seat (a flux being used in the case of solder) so as to effectually exclude air.
When paraffin wax is used a covering plate G may be applied over it and
soldered by its edges to the cover C in order to protect it. Or it may be
covered by a paper label.
The final seal of paraffin wax or solder and the covering plate or label in the
case of wax would be applied in the same way in the case of Figure 4, the plug
being sufficiently countersunk in its seat to receive said seal.
In the case of a glass bottle paraffin wax only would be used to cover the
bush and also the cork which would be slightly countersunk in the mouth of the
bottle to receive the seal as shown in Figures 5 and 6.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what I
claim is
1. The herein described method of sealing tins and other receptacles containing
alimentary substances which consists in driving a plug into the escape orifice
after the expulsion of the contained air but before the cessation of internal
steam pressure generated by heating the contents, and afterwards covering the
plug and its seat with a layer of impermeable material, substantially as
specified.
2. The herein described means of preliminarily sealing tins and other recep-
tacles for alimentary substances whilst under internal steam pressure, said means
consisting of a plug driven into the escape orifice as an interim means of
closure, substantially as specified.
3. The herein described means of sealing tins and other receptacles for ali-
mentary substances whilst under internal steam pressure, said means consisting
of a plug driven into the escape orifice as an interim means of closure, in com-
bination with a covering layer of impermeable material such as melted paraffin
wax or melted solder applied as described.
Dated this 22nd day of June 1900.
A. M. & WM. CLARK,
Chartered Patent Agents, 53, Chancery Lane, London.