Improvements in and connected with Canning Goods.
Year: 1898

page_text: Date of Application, 20th June, 1898
Complete Specification Left, 21st Dec., 1898-Accepted, 4th Feb., 1899
We, AUGUST OPAWSKI, of 11, Zeinlhofer-gasse, Merchant, and Dr. ERNST MURMANN,
of 14, Kettenbrücken-gasse, Chemist, both of Vienna, in the Austrian Empire, do
hereby declare the nature of this invention to be as follows:-
This invention relates to sealed sheet iron cans for preserving foods of such a nature
as to require heating before being eaten.
Hitherto, it was necessary for heating such preserved foods, to provide hot water,
or a wood or spirit fire. Now this invention has for its object to obviate this
necessity.
According to the invention a two-chambered sheet iron receptacle is so connected
with the can that the sides of the said receptacle are either in contact with the
contents of the can, or are partly formed by the sides of the said can. The two
chambers of the receptacle, separated from each other by a partition, are filled with
two different substances having chemical affinity with one another (one of them being
by preference in a liquid state) whereby on the partition between the two chambers
being pierced, chemical reaction takes place and heat is developed. If one of the
two substances referred to be water, which may be found nearly everywhere in nature,
the said receptacle may have but one chamber. In this case, the outer side of the
receptacle is pierced when the food is required for use and water is introduced
therein.
In the case of two-chambered receptacles, one of the chambers may contain a
permanent device for piercing the partition between the two chambers or for
loosening a soldered in partition, the said device consisting of a pin so held in position
in the chamber that it pierces or loosens the partition when a portion of the receptacle
is knocked in.
Where water is used it has preferably added to it a suitable substance for preventing
it freezing such for example as certain salts, glycerine alcohol etc.
1000
Improvements in and connected with Canning Goods.
We, AUGUST OPAWSKI, of 11, Zeinlhofer-gasse, Merchant, and DR. ERNST MURMANN,
of 14, Kettenbrücken-gasse, Chemist, both of Vienna, in the Austrian Empire, do
hereby declare the nature of this invention and in what manner the same is to be
[Price 8d]

page_text: performed, to be particularly described and ascertained in and by the following
statement —
This invention relates to cans for preserved foods which before use are warmed in
their said cans, the object of the invention being to obviate the necessity for the
preparation of warın water for heating the food or of igniting wood or spirit.
According to the invention a two-chambered sheet-iron receptacle is so connected
with the can that the food itself is in contact with the sides thereof or in such a
manner that its sides are partly formed by those of the said can. Into each of the
two divisions of the receptacle, which are separated by a partition, we introduce
different substances of distinct chemical affinity for one another and one of which is
a liquid. By reason of this arrangement, when the partition is perforated chemical
reaction takes place and heat is developed. If one of the two substances be water,
which may be found nearly everywhere in nature, the second chamber of the
receptacle can be dispensed with. In this case the receptacle is pierced when the
food is required for use and the water is introduced therein. The receptacle with
two chambers can be provided with a device for piercing or perforating the partition.
This device consists of a pin which is soldered in one of the chambers in such a
manner that it pierces or separates the diaphragm when the outside of the can is
pressed inwards.
As in slaking freshly burnt lime 13,600 calories are developed per molecule of the
hydrate formed, many attempts have been made, and it has been many times
proposed, to employ this process for the present purpose. Burnt lime is slaked with
ordinary water, however, relatively very slowly and still more slowly if the water has
had added to it alcohol or glycerine for the prevention of freezing. The reaction,
therefore, is considerably delayed when the burnt lime has been preserved any length
of time after burning-obviously without exposure to the air. A quarter of an hour
often passes before heat is developed, and the development of heat is only slight;
even with lime in small pieces and in contact with a good conductor of heat it is
scarcely appreciable.
Now, this invention has for its object to suitably hasten the reaction between
unslaked lime and water.
The object is attained by bringing the unslaked lime into contact with a water
transmitting substance instead of with water. Many salts and acids have the
property that when they are dissolved in water a number of molecules of the water
are so loosely combined that the said water molecules can be given up to other
combinations more easily than the molecules of the groups which themselves form
the water. After yielding up the water to the other combination a further com-
bination of water molecules takes place from the surrounding water and this action
goes on so that the salts or acids used remove the water molecules so to say and
transmit them to the other combination.
Amongst the media for conveying the water chloride of calcium is particularly
suitable; next in order come calcium bromide and iodide, after which succeed
magnesium chloride, bromide and iodide; ammonium chloride, bromide and iodide;
zinc chloride, bromide and iodide and all soluble chlorine bromine and iodine salts of
inorganic bases (for example iron oxide) and organic bases (for example aniline,
phenylhydrazin) which are decomposed by lime. The only exceptions are the fixed
alkalies, the chlorides of which do not act at all and the bromides and iodides of
which only act in a weak manner.
Very dilute hydrogen chloride, bromide and iodide which give rise to the formation
of the corresponding halogen compounds of calcium act of course quite as quickly
as the calcium compounds themselves. The following bodies act slowly,-Calcium,
magnesium, aluminium, ammonium, potassium, sodium and barium nitrates, very
dilute nitric and sulphuric acids, magnesium sulphate, ammonium molybdate etc.
Alkaline sulphates; alkaline fluorides; nitrites; alkaline carbonates, alkaline lyes;
sodium tungstate etc., do not act or cause retardation.
The action of chloride of calcium is so intense that unslaked lime for example,
which only reacts weakly with distilled or well water and then only after about ten

page_text: minutes interval, when brought into contact with a % solution of chloride of
calcium, gives off vapour in a few seconds. If the said lime be introduced into a 3%
solution of chloride of calcium (Ca Cl₂) the development of heat takes place
explosively.
The accompanying drawing illustrates a can made according to the invention.
Figure 1 is a vertical section of the said can; and,
Figure 2 is a sectional plan, the section being upon the line 2-2 of Figure 1.
As shewn in the drawing the cylindrical container c with the bottom c¹ is soldered
into a hole in the cover a of the container b by means of its flange c². The diameter
of the holder c is so chosen that the said holder for a certain capacity nearly reaches
to the bottom a¹ of the container b. This holder c is designed to receive unslaked
lime or a mixture thereof with a water transmitting material.
In the open upper end of the holder c there is soldered a second holder f of a
similar form but of smaller dimensions, its flange f resting upon the flange c².
This holder is filled with water or with an aqueous solution of a water
transmitting material. The holder f is closed by means of a convex cover h soldered
thereto and it contains the pin j for perforating the bottom 2 which here takes the
place of the above described partition. The pin passes through a hole f³ in the
holder-bottom and is provided underneath the said bottom with a head which is so
fitted thereto that it closes the hole f³. If, now, the convex cover h be flattened by
a blow from something heavy the head j¹ of the pin ; is freed, that is, unsoldered,
and the liquid can enter the chamber c.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. A heating device for preserved food cans comprising a two-chambered sheet-
metal container fitted in the can one of which chambers contains unslaked lime and
a water transmitting material and the other of which contains water; or one of
which chambers contains unslaked lime alone and the other an aqueous solution of
the water transmitting material, substantially as hereinbefore described.
2. In a heating device for preserved food cans of the kind described in Claim 1 a
single chambered container which contains unslaked lime and a water transmitting
material so that by perforating or piercing the outer chamber and introducing water
heat is quickly developed substantially as hereinbefore described.
3. In a heating device for preserved food cans of the kind described in Claims 1
and 2 the employment of chloride of calcium as the substance for transmitting the
water, substantially as herein before described.
4. In a heating device for preserved food cans of the kind described in Claims 1
and 2 the addition to the lime or to the water of chlorides, iodides, bromides or
nitrates, which by double decomposition with the lime produce calcium chloride,
bromide or iodide or calcium nitrate, substantially as set forth.
5. In a heating device for preserved food cans of the kind described in Claim 1,
a pin j introduced into the liquid-chamber f, one end of which pin is in contact with
the partition 2 between both chambers and the other end is supported upon the
outer side h of the chamber so that by depressing the said side the partition is
perforated or pierced, substantially as described and illustrated.
6. In a heating device for preserved food cans of the kind described in
Claims 1 and 5 a head upon the pin ; which is soldered in a hole in the
partition, substantially as described and illustrated.
Dated the 21st day of December 1898.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicants.