An Improved Process of Canning Food.
Year: 1898

page_text: Date of Application, 12th Apr., 1898-Accepted, 25th June, 1898
QUALI DIE DIECIFICATION.
An Improved Process of Canning Food.
I, EDWIN NORTON, of Maywood, in the County of Cook, State of Illinois, United
States of America, Manufacturer, 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:-
-
The purpose of my invention is to improve the flavor of the canned food, _to
remove therefrom the flat taste imparted to the food by the method of canning
now commonly employed, and to preserve in cans articles of food that cannot be
canned successfully by present methods. Also to prevent the formation in
the can of deposits of sulphite of tin, which deposits are now of common occur-
rence in vegetables which contain sulphur and are caused by the air sealed up in
the cans uniting with the sulphur in the vegetables and the tin coating of the
metal and forming sulphite of tin, which deposits on the goods and also on the
inside of the can top, above the air space left in the cans in filling, frequently
to such an extent as to make the goods unsightly, and particularly as the
appearance of this sulphite" is so nearly like that of iron rust that only a
chemical analysis will show the difference.
<<
I overcome this difficulty that has always been present to a greater or less
extent, and herein my invention consists: By first withdrawing the air from the
cans, after they have been filled, to about 90 per cent. of the amount in them,
then sealing the cans and cooking the contents in vacuum. I have discovered by
repeated tests that when a vacuum, say of 25 feet, is maintained in the cans
during the time the food is being cooked that the flavor of the goods is maintained
thereby, and also that the removal of this air from the can before the contents are
subjected to the heat of the water or steam bath in the cooking vessel or retorts
prevents the formation of sulphite of tin deposits on the can and contents. And
another advantage of my improved process over the old is that when the air is
withdrawn from the can and contents before the cooking is done, there is less
expansion and strain upon the cans and their soldered seams than heretofore,
thereby saving a large amount of loss from bursting of cans in the cooking
retorts from undue pressure on the metal of the can.
In the accompanying drawing, which forms a part of this specification, to
enable my invention to be more fully and clearly understood by those skilled in
the art, I have illustrated suitable apparatus for use in practising my invention,
the same being of the construction which I prefer to employ.
In the drawing Fig. 1 is a sectional view showing a suitable construction of
can for use in practising my invention; Fig. 2 is a sectional view of a suitable
construction of air pump receiver or vacuum chamber for use in mechanically
exhausting the air from the cans and hermetically sealing and securing the covers
to the cans by a vacuum or atmospheric pressure seal: Fig. 3 is a sectional view
of the can showing it thus sealed; Fig. 4 is a sectional view of an expansion
seaming machine suitable for use in sealing and securing the covers to the cans
by the mechanical seal or seam; Fig. 5 is a sectional view of the can with its cover
LD 077

page_text: thus sealed to the can both by the vacuum or atmospheric pressure seal and the
mechanical seal. Fig. 6 is a sectional view of a clamping device suitable for use
in clamping the covers on the cans to prevent any danger of the steam pressure
created by the cooking operation in the can from breaking or injuring the her-
metic seal uniting the cover to the can and reinforcing the can while being
subjected to the cooking step or operation, and Fig. 7 is a sectional view of a
cooking retort suitable for use in cooking and sterilizing the contents of the can.
In the drawing similar letters of reference are employed to indicate like parts
in all the figures.
The cans used in practising my invention must be so constructed that when
they are filled and the covers put on and they are placed in the receiver of a
vacuum pump, or in contact with any mechanical, appliance that will produce
a vacuum in them, that the covers can be sealed to prevent the return of the air
into the cans, Any suitable construction of can that will admit of this will
answer. Such a construction is shown in the drawing at Fig. 1, the same being
the construction I prefer to use. After the cans have been sealed by a vacuum
joint or seal and before they are ready to be cooked, they should have their covers
securely fastened on; so that when placed in the cooking retorts and subjected to
steam heat sufficient to sterilize and cook the contents the mechanical seal will
assist in holding the cans sealed air tight during the cooking operation, and until
the atmospheric pressure is again restored or not counterbalanced by the steam
pressure in the can, by cooling off the cans and their contents. This can be done
in any suitable way. I have shown in the drawing a very good and convenient
mechanism, which consists in passing the cans through what is called an expan-
sion capper or seaming machine (shown in Fig. 4,) which expands the counter-
sunk head of the can below a roll on the upper end of the can body and locking
the cover securely to the can. This closure also prevents the tops coming off in
the case at any time the vacuum seal is broken by the goods in the can spoiling
from improper cooking, or other causes. After the mechanical capping or sealing
operation I next place the cans in clamps, a number of rows of cans, for con-
venience being firmly clamped by means of an upper and lower plate connected
by a threaded shaft and provided with a nut for screwing down the upper plate
to clamp the cans. This clamp is illustrated in Fig. 6 of the drawings. Any
device that will prevent the seal being broken while the cooking is done will
answer as well.
The cans, having been filled with food, a vacuum produced by mechanical
means and the covers sealed on, to maintain the vacuum during the cooking pro-
cess, are now placed in an ordinary cooking retort, illustrated in Fig. 7 of the
drawing, and cooked as usual, except that in my process I have only about
ten per cent. of the air remaining in the cans to be sterilized with the food. And
this small quantity does not injure the flavor of the food, and the smallness of the
quantity of air remaining in the can prevents the forming of sulphite of tin in
case tin cans are used. The process can be used in vessels other than tin, such
as glass. After the cooking the cans are immersed in cold water, or cooled off
in any suitable manner before being removed from the clamps.
Referring now to the drawing: A represents the body of the can and B the
cover. The can body has at its upper or mouth end an inwardly projecting roll
or shoulder a The cover B has an outer flange b and an inner flange b¹ forming
between them an annular channel or seat 62 for a packing 63, so that when the
filled can A is placed within the receiver of a vacuum pump with the cover B
loosely in place on the can, the air may be readily pumped out of the can through
its open mouth, and so that when the pressure is suddenly restored to the receiver
the cover will be instantaneously and hermetically sealed and secured thereto by
a vacuum or atmospheric pressure seal.
C (Fig. 2) is the receiver of a vacuum pump in which the cans A are placed,
preferably on a suitable truck C¹ piled in tiers and with a follower plate C³ on
top of the pile to better insure the moving of the covers straight and squarely

page_text: home on the cans when the pressure is suddenly restored. C³ is a three-way valve
for opening and closing the communication between the receiver C and the
pipe leading to the vacuum pump or the air inlet pipe C5. The receiver C'is
preferably furnished with doors C at each end so that the trucks of cans can be
rolled in at one end and out at the other.
In Fig. 3 one of the cans is illustrated after being operated upon by the
receiver C, the cover B being forced home on the can and hermetically sealed and
secured thereto by the atmospheric pressure or vacuum seal.
The expansion seaming machine which I prefer to employ for forming the
mechanical seal uniting the cover to the can does this work by making an out-
ward bend or crimp 6 in the inner flange 6 of the cover, and thus locking it
out under and against the inwardly projecting roll a on the can body. And, as
illustrated in Fig. 4, it preferably comprises the clamping ring & surrounding
and embracing the upper end of the can body, seaming rollers d journaled on
levers ², hinged by pivots to a rotating ring or sleeve splined to the shaft ³
which is provided with a grooved head do that engages the inner ends of said
levers.
In Fig. 5 the can A is illustrated in this next step of the process, that is to say
after the cover has been mechanically sealed and secured by the seaming machine
illustrated in Fig. 4.
The cans, as illustrated in Fig. 5, are next placed between a pair of clamps FF
which are connected and adapted to be forced together by the clamp screws F¹.
The cans are preferably placed between the clamps in tiers or columns, as illus-
trated in Fig. 6. After being thus clamped the cans are next placed in the cook-
ing retort G, this being preferably done by placing the cans on a suitable truck G¹
and running the truck into the retort through the door G³ thereof. G³ represents
the steam inlet pipe and G4 the safety valve.
Having now particularly described and ascertained the nature of my said in-
vention, and in what manner the same is to be performed, I declare that what I
claim is:-
1st. The herein described process of canning hermetically sealed food, consist-
ing in placing the food in cans provided with covers adapted to be sealed by
atmospheric pressure, placing the cans with their covers in place within a
receiver, exhausting the air in the cans, and sealing the covers on the cans by the
sudden admission of air to the receiver, substantially as described.
2nd. The herein described process of canning hermetically sealed food, con-
sisting in placing the food in cans provided with covers adapted to be sealed by
atmospheric pressure, placing the cans with their covers in place within a receiver,
exhausting the air in the cans, sealing the covers on by the sudden admission of
air to the receiver, then locking the covers securely to the cans so as to form an
air-tight mechanical seal, and finally cooking the contents while in vacuum,
substantially as described.
3rd. The herein described process of canning hermetically sealed food, which
consists in placing the food in cans with covers for the entire top, placing such
filled cans with their covers in place within a receiver, exhausting the air from
the receiver, cans, and contents, and seaming the covers on the cans so as to form
an air-tight mechanical seal, substantially as described.
4th. The herein described process of canning hermetically sealed food, which
consists in placing the food in cans with covers for the entire top, placing such
filled cans with their covers in place within a receiver, exhausting the air from
the receiver, cans, and contents, and seaming the covers on the cans so as to form
an air-tight mechanical seal, then clamping the filled cans and processing the
same to sterilize the contents, substantially as described.
5th. The process of canning food or other articles, consisting in the following
steps; first, filling the cans, next extracting the air therefrom, next, sealing the
covers on the cans with a vacuum seal, next locking the covers securely to the

page_text: cans by seaming to prevent the escape of their contents or of steam or gases aris-
ing therefrom during the next or cooking step, and finally cooking the contents
while in vacuum, substantially as shown and described.
6th. The process of canning hermetically sealed food, consisting in the follow-
ing steps; first filling the cans, next producing by mechanical means as near a
perfect vacuum in the cans as practicable by removal of the air therefrom, next
sealing the covers on the cans by seaming to prevent the return of air thereto and
to prevent the escape of their contents or of steam or gases arising therefrom dur-
ing the next or cooking step, and next cooking the food contained in the cans
while in a vacuum, whereby the injurious effects upon the cans and contents of
the air always heretofore sealed up in the cans with the food, is avoided, substan-
tially as shown and described.
7th. The herein described process of canning hermetically sealed food, con-
sisting in placing the food in cans provided with covers adapted to be sealed by
atmospheric pressure, placing the cans with their covers in place within the
receiver, exhausting the air in the cans, and sealing the covers on by the
sudden admission of air to the receiver, next removing the cans from the receiver
and securely sealing the covers to the cans by a mechanical seal to prevent the
escape of their contents or of steam or gases arising therefrom, next placing the
cans in suitable clamps to prevent the action of the steam cooking from breaking
the sealed joint between the cans and covers, placing the cans in a cooking retort
and sterilizing and cooking the contents while in vacuum, next removing the
cans from the retort and cooling the contents, and next removing them from the
clamps, substantially as shown and described.
101
1 1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.