IMPROVEMENTS IN THE MANUFACTURE OF SEAMED TIN VESSELS FOR USE IN HERMETICALLY ENCLOSING AND PRESERVING FOOD, CHEMICALS, OR OTHER SUBSTANCES, AND IN APPARATUS FOR EXHAUSTING THE AIR FROM AND EFFECTING THE HERMETIC CLOSING OF SUCH VESSELS OR OTHER RECEPTACLES FOR A LIKE PURPOSE
Year: 1879

page_text: LETTERS PATENT to Thomas George Fonnereau Dolby, of Dulwich, in tho
County of Surrey, Manufacturer, for the Invention of "IMPROVEMENTS IN
THE MANUFACTURE OF SEAMED TIN VESSELS FOR USE IN HERMETICALLY
ENCLOSING AND PRESERVING FOOD, CHEMICALS, OR OTHER SUBSTANCES, AND IN
APPARATUS FOR EXHAUSTING THE AIR FROM AND EFFECTING THE HERMETIC
CLOSING OF SUCH VESSELS OR OTHER RECEPTACLES FOR A LIKE PURPOSE,"
PROVISIONAL SPECIFICATION left by the said Thomas George Fonnereau
Dolby at the Office of the Commissioners of Patents on the 11th October
1879.
THOMAS GEORGE, FONNEREAU DOLBY, of Dulwich, in the County of Surrey,
Manufacturer. IMPROVEMENTS IN THE MANUFACTURE OF SEAMED TIN VESSELS
FOR USE IN HERMETICALLY ENCLOSING AND PRESERVING FOOd, Chemicals, oR
OTHER SUBSTANCES, AND IN APPARATUS FOR EXHAUSTING THE AIR FROM AND
EFFECTING THE HERMETIC CLOSING OF SUCH VESSELS OR OTHER RECEPTACLES FOR
A LIKE PURPOSE."
My Invention has reference to the manufacture of seamed tin vessels to be
employed for the preservation of food or provisions, and which are to be hermetically
closed (in the manner described in the Specification of Letters Patent granted to
me on the 8th August 1878, No. 3140) by a lid or cover kept down (after the air
has been exhausted from the vessels) by atmospheric pressure (with a suitable
packing interposed) upon a flange, which is formed around either the inside or
outside edge of the top of the vessel. The Invention has also reference to the
apparatus employed for exhausting the air from the vessels or from other receptacles
for a like purpose in order that they may be hermetically closed in the manner
aforesaid, and the food or other substance contained therein be preserved.
In these vessels it is essential in order to obtain the required hermetic closing
that the flange above referred to, whether it be an inside or outside flange, shall be
perfectly smooth and flush all round. But in the manufacture of a flanged seamed
tin vessel in the ordinary manner the overlapping edges of the flange produce an
unevenness, which is fatal to the obtaining of hermetic closing in the mauner
before referred to.
Now, in order to form the upper surface of the flange perfectly smooth and flush,
after the edges of the body part of the vessel have been brought together and united
in the ordinary manner, and after the bottom has been soldered thereto, I form the
flange as follows:-I either throw the edge over by a "jenny" in the usual way,
and then finish it, and make the top surface smooth by dies of special construction,
as about to be described, or I perform the whole process by special dies.

page_text: These dies, whether for performing the whole process or for smoothing the flange
after having been thrown over by the "jenny," are made as follows:-
That for the top surface of the flange is plain, but of course of the proper shape,
while that for the under surface is formed with a recess which is equal to or slightly
exceeds in depth the thickness of the metal of the tin, and in length the extent of
the overflap, so that when the dies are forced together to form the flange, the extra
thickness of the metal is depressed or forced into the said recess, and the upper
surface of the flange is therefore formed perfectly true and flush. The seam at the
flange may then be resoldered, if necessary, to make it quite sound.
I do not limit myself to making the overlap correspond with the amount of seam,
as a piece clipped off from the underlap, and then struck into a corresponding
indent in a die would produce the same result or the whole of the underlap of the
flange could be clipped, and the flange brought edge to edge forced true by dies,
and strengthened by solder to accomplish the same end.
I construct as follows the apparatus for exhausting the air from these vessels or
from other like receptacles, which have to be hermetically closed by lids, kept down
solely by atmospheric pressure, in order that the contents of the vessels may be
preserved :-
In a cylinder which may be open at its lower end works a plunger or piston.
The plunger rod is connected with any suitable mechanism for imparting to it up
and down motion by hand or other power. The cover to the cylinder is made
by preference removable. A chamber is either permanently fixed to the cover so
as to be removable therewith or attached to the cover, so as to be separately
removable; this chamber should correspond in shape as much as practicable with
the vessels or receptacles from which the air has be extracted, and should be only
slightly larger, so as to leave only a small air space at the sides and top. And in
order to allow of the pump being advantageously employed for exhausting air from
vessels of different shapes, I provide a series of correspondingly shaped chambers
which are removable either with or without covers. The chamber is either open
at the bottom or formed at the bottom with one or more holes. The cover of the
chamber is composed of a plate to fit hermetically, preferably by atmospheric
pressure, and with the aid of an india rubber washer or other packing upon the
upper edge of the vessel. There is an aperture in the cover provided with a valve
which I prefer to be in the form of a ball, which may be elastic or fit upon an elastic
seat, and is kept from falling by a suitable cage, which may conveniently form a
handle to the cover.
The operation is as follows:-The plunger being at the top of its stroke, and a
receptacle (containing the food or substance to be preserved) with its loose cover
and an elastic washer between the cover and receptacle having been placed in the
chamber, the cover of this chamber is put on. The plunger is then made to
descend, whereby all the air in the chamber and in the food receptacle is withdrawn
(the cover of the said receptacle rising freely to allow the air to escape), while the
pressure of the outer atmosphere keeps the cover of the chamber hermetically closed,
so that no more air can enter. By the time the plunger has reached the bottom of
its stroke, the air in the chamber and food receptacle will have been sufficiently
exhausted. The ball or valve is then forced off its seat so as to admit air to the
chamber when the cover of the food receptacle will be immediately hermetically
closed by the atmospheric pressure. The cover of the chamber is then lifted off, the
food receptacle removed, another receptacle introduced, and the plunger having
meanwhile been returned to the top of the cylinder, the operation is repeated. It is
important that the chamber should be only so much larger than the food receptacle,
as is necessary to allow the air to pass readily between them, because if there were a
considerable difference between the size of the said chamber and that of the
receptacle, the volume of air to be extracted from the chamber would be large, and
require a proportionate pump power.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Thomas George Fonnereau Dolby in the Great Seal Patent Office
on the 10th April 1880.
THOMAS GEORGE FONNEREAU DOLBY, of Dulwich, in the County of Surrey,
Manufacturer. "IMPROVEMENTS IN THE MANUFACTURE OF SEAMED TIN VESSELS
FOR USE IN HERMETICALLY ENCLOSING AND PRESERVING FOOD, CHEMICALS, OR
OTHER SUBSTANCES, AND IN APPARATUS FOR EXHAUSTING THE AIR FROM AND
EFFECTING THE HERMETIC CLOSING OF SUCH VESSELS OR OTHER RECEPTACLES FOR
A LIKE PURPOSE.”
My Invention has reference to the manufacture of seamed tin vessels to be
employed for the preservation of food or provisions, and which are to be hermetically
closed (in the manner described in the Specification of Letters Patent granted to
me on the 8th of August 1878, No. 3140) by a lid or cover kept down (after
the air has been exhausted from the vessels) by atmospheric pressure (with a
suitable packing interposed) upon a flange, which is formed around either the inside
or outside edge of the top of the vessel. The Invention has also reference to the
apparatus employed for exhausting the air from the vessels or from other receptacles
for a like purpose in order that they may be herinetically closed in the manner
aforesaid, and the food or other substance contained therein be preserved.
In these vessels it is essential in order to obtain the required hermetic closing
that the flange above referred to, whether it be an inside or outside flange shall be
perfectly smooth and flush all round. But in the manufacture of a flanged seamed
tin vessel in the ordinary manner the overlapping edges of the flange produce an
unevenness, which is fatal to the obtaining of hermetic closing in the manner
before referred to.
Now, in order to form the upper surface of the flange perfectly smooth and flush,
after the edges of the body-part of the vessel have been brought together and united
in the ordinary manner, and after the bottom has been soldered thereto, I form tlie
flange as follows:-I either throw the edge over by a "jenny" in the usual way,
and then finish it, and make the top surface smooth by dies of special construction,
as about to be described, or I perform the whole process by special dies.
These dies, whether for performing the whole process or for smoothing the flange
after having been thrown over by the "jenny," are made as follows:-That
for the top surface of the flange is plain, but of course of the proper shape, while
that for the under surface is formed with a recess which is equal to or slightly
exceeds in depth the thickness of the metal of the tin, and in length the extent of
the overlap, so that when the dies are forced together to form the flange, the extra
thickness of the metal is depressed or forced out into the said recess, and the upper
surface of the flange is therefore formed perfectly true and flush. The seam at the
flange may then be resoldered, if necessary, to make it quite sound.
Figures 1 to 4 of the annexed Drawings serve to illustrate this part of my
Invention. Figure 1 is a side elevation of a finished vessel with an outwardly
turned flange constructed according to my Invention; Figure 2 is a perspective
view shewing the appearance of the flange if the vessel were unrolled or flattened
out; Figure 3 is a section of a vessel having an inturned Hange constructed
according to my Invention, and Figure 4 shews the flange and body of the vessel
flattened out.
I do not limit myself to making the overlap correspond with the amount of seam,
as a piece may be clipped off from the underlap, and the remainder be then struck
into a corresponding indent in a die or the whole of the underlap of the flange
could be clipped off, and the flange be then brought edge to edge forced true by
dies, and strengthened by solder to accomplish the same end.
What I claim under the first part of my Invention is:-The manufacture of
seamed tin vessels with a flange turned at the top, the upper surface of the

page_text: said flange being made true, smooth, and flush all round, substantially in the manner
and for the purpose herein before described.
I now proceed to describe the second part of my Invention, that is to say, my
improved apparatus for exhausting the air from these vessels or from other like
receptacles which have to be hermetically closed by lids kept down solely by
atmospheric pressure, in order that the contents of the vessels may be preserved.
Figures 5 and 6 of the annexed Drawings serve to illustrate this part of my
Invention; Figure 5 is a vertical mid section of the apparatus, and Figure 6 is a
plan of the sanie. A is a cylinder which may be open at its lower end or provided
with a perforated cover; B is a packed plunger or piston fitted to and adapted to
play in the cylinder; C is a piston rod which passes through and is guided by the
head D. To this piston rod may be attached a treadle, if desired, or other mechanism
whereby the piston may be conveniently operated. E is the upper cylinder
head which is made by preference removable. Upon this is mounted a chamber F
to receive the vessel or can from which the air is to be exhausted. This chamber
is by preference made removable from the cylinder head so that it may be
replaced by others of different shapes and sizes to fit the different sizes of the cans
or vessels, as I deem it advisable that the said chamber should correspond very
nearly, both in size and shape, with the vessels operated upon, so as to leave
only a narrow space for the air around the said vessels. G represents a can
arranged in the chamber F in position to be operated upon.
The chamber F is provided with a cover a adapted to be hermetically closed by
some suitable means, I have shewn it provided with a flange or rim which finds a
seat upon a packing ring, upon a projecting rim on the chamber F, and I prefer
that it should be held in place by atmospheric pressure alone, but it may be held
down by other means. In this cover is a valvular opening adapted to be closed
by a valve of any convenient form. The valve shewn is a spring valve c, which is
binged at d, and is formed with a finger piece or extension e, by means of which it
is operated. Holes b, b, through the cover E serve to form a communication
between the chamber F and the cylinder A. f is a disc on a plunger g, which
passes through a cap h, screwed to the cover a; i is an air tight diaphragm
between the plunger g and the cap and cover; k is a cross bar fixed by means of a
nut to the top of the plunger g; this cross bar has at each end a hole or eye to
pass over vertical pins m, m, fixed to the cover a, and each of these pins is fitted
with a spring; n is a hand lever,' by means of which the plunger g can be forced
down as required. This lever is centred at o to an upright p, and it bears on an
antifriction roller q at the top of the plunger g.
The operation is as follows:-The piston B being pushed to the upper end of the
cylinder, as shewn, a vessel G is placed in the chamber F. On its top is first
placed a packing ring, and then a suitable lid or cover. The cover a is then put on
the chamber F, and the piston B forced down. This exhausts the air from the
vessel G and chamber F, the lid of the vessel rising freely to let the air escape.
The lever n is then brought down, so as to force down the plunger g, and bring the
disc fupon the lid of the vessel G; while this lid is thus held down the valve c is
opened so as to admit the outer air to the chamber F, or the piston is raised to allow
the air to return, and the lid of the vessel G is immediately fixed in place by
atmospheric pressure. The lever being now thrown back the cover a may be
removed, the vessel G taken out, another vessel introduced, and the cover a
returned, when the operation may be repeated, and so on indefinitely. The power
of the springs should exceed that of the atmospheric pressure upon the area of the
plunger g. If desired, the disc f, plunger g, lever n, and parts connected therewith,
may be dispensed with, the air being in such case re-admitted to the chamber F
when the lid of the vessel is not held down except by its own weight, but I find in
practice that if the lid be not held down in the manner described or by some other
equivalent arrangement while the air is being re-admitted to the chamber some air
will occasionally re-enter the vessel G before the lid is sufficiently held down by the
atmospheric pressure.

page_text: What I claim under the second part of my Invention is,—
First. Constructing apparatus for exhausting the air from and effecting the
hermetic closing of vessels or cans used for preserving food or other substances
with a cylinder piston and rod, the cylinder being in communication with a
chamber in which the vessel or can to be operated on is placed, and the said
chamber being fitted with a removable cover provided with a valve, all sub-
stantially as herein before described.
Second. Constructing the apparatus with means or appliances for exerting
pressure upon the lid of the vessel or can while air is being re-admitted to the
chamber, substantially as and for the purpose herein before described.
Third. The improved combination of parts, substantially as herein before described
and shewn in the annexed Drawings, forming improved apparatus for exhausting
air from and effecting the hermetic closing of vessels or receptacles of the kind
herein referred to.
In witness whereof, I, the said Thomas George Fonnereau Dolby, have here-
unto set my hand and seal, this Tenth day of April, One thousand eight
hundred and eighty.
T. G. F. DOLBY. (L.S.)