GB2089970A

GB2089970A - Self-heating, Single-portion Container for Foods and Beverages

Info

Publication number: GB2089970A
Application number: GB8137179A
Authority: GB
Original assignee: IRTI Srl
Current assignee: IRTI Srl
Priority date: 1980-12-10
Filing date: 1981-12-09
Publication date: 1982-06-30
Also published as: IT1165571B; GB2089970B; IT8050339A0; FR2495459A1; DE3148758A1; FR2495459B1

Abstract

A self-heating container comprises a first container 1 for beverages and foods made of synthetic material and closed at the top by a tear-off foil 9, and a second container 2, made of metal, for housing reagents to provide an exothermic reaction. The second container 2 is divided by a frangible partition 5 into a lower zone containing solid reagents and an agent for priming the reaction and an upper zone 4 containing liquid reagents with an added hygroscopic substance capable of regulating the velocity of the exothermic reaction. Pressure downwards on the container 1 ruptures the partition 5 to start the exothermic reaction. <IMAGE>

Description

SPECIFICATION Self-heating, Single-portion Container for Foods and Beverages This invention relates to a self-heating, single-portion container for beverages and foodstuffs. In particular, the invention concerns a self-heating container for beverages and foodstuffs, in which the heat supply is ensured extemporarily by chemical substances capable of producing an exothermic reaction at a controlled rate.

It is known from the current state of the art that a number of attempts have been made to overcome the problem of devising a single-portion, self-heating container for beverages or foodstuffs, but without the solutions proposed having given sufficiently satisfactory results to permit industrial production with a guarantee of practicality and safety.

In particular, technical teaching (e.g. Italian Patent 942.063) is well known for the production of a self-heating container for coffee and other drinks, which proposes the use of chemical substances, inside one part of the container, capable of providing by exothermic reaction and at the moment of use, the calories required for the heating desired. However, it should be noted that no measures are indicated for controlling this reaction. The reaction thus takes place with the formation of noxious gases, so much so that holes are provided in the container to allow the gases to escape into the atmosphere. This results in a complication of the method of manufacture and a weakening of the structure of the container, and this without even taking into account the danger caused by the escape of the gases.

Another solution proposed by the prior art (see Italian Patent Application 40456 A/77) resorts to the use of calcium chloride and water as means designed to supply by reaction the calories required.

However, it should be noted that, although the problem of noxious gases is eliminated, the reaction takes place in a closed environment with perfect sealing (a sealed chamber) with the by-no-meansnegligible danger of explosion of the container-it being well known that there is a high rate of reaction between calcium chloride and water-and without doubt this has impeded effective production on an industrial scale of this type of container.

Similarly, the solution of using an unsealed reaction chamber has not lead to any technical progress because of the excessive formation of steam at the moment of use and because of the low efficiency arising from the corresponding heat loss.

Therefore, it is the object of this invention to devise a container of the type described in which, on the one hand, there are utilised both reactions which do not involve the formation of noxious gases and an open reaction chamber, so as to avoid the development of excessive pressure in its interior, and, on the other hand, the reaction rate is controlled so as to avoid any undesirable formation of steam.

This invention also has the object of making available a container in which the substances (beverages or foods) and the heat source required to heat them are arranged in a unitary structure which ensures:- minimum dimensions and weight; immediately utilisable heat source; rapid but controlled heating; absence of gas and steam losses; elimination of danger to the user; and acceptable cost.

If one now considers a beverage or foodstuff having a volume of 40 ml, which is a reasonable quantity for a single portion consisting, for example, exclusively of water to be heated from a temperature of 200C to that of 700 C, in theory 2000 calories are required. To these it is necessary to add the calories required to heat the container, the losses due to dissipation, the calories consumed to heat the reagents and the residual heat generated once the useful contents have been extracted. A total of 5000-6000 calories are required.

It is known that numerous isothermal reactions exist which are able to provide this amount of heat with a relatively low quantity of reagents, but it is necessary to exclude all reactions which may become explosive, as well as those which provide, as reaction product, gases which are noxious to a greater or lesser extent.

Among the possible reactions, there are now taken into consideration only those reactions which are of practical use because of the low cost of the reagents and because of the small volume required, namely: (1) CaO+H20=Ca(OH)2 g 20+9 6,4=5570 calories (2) CaCI2+6H20=Cacl26H20 g 25+g 24,4=5225 calories (3) AlCl3+6H20=AlCl36H20 g 11 +g 8=5368 calories (4) Na2SO4+ 1 OH20=Na2S0410H20 g 40+g 50=5480 calories (5) Mgo+H2o=Mg(OH)2 g 25+ g 11,2=5475 calories By simple observation, it is evident from the above data that the most advantageous reaction should be (3) because of the small quantity of reagents used. However, it is not without drawbacks in view of the fact that it proceeds too quickly and is difficult to control.

Reaction (1) also is certainly of interest. However, in this reaction the priming is difficult and therefore the hydration process is started with difficulty. Once a certain temperature is reached (about 400 C) the reaction adopts an exponential course and terminates within a very short time.

In the following, there will be illustrated the system used, according to this invention, for controlling this reaction, with the practical result of achieving the immediate generation of heat and at the same time the slowing down of its emission, so as to prolong its activity for several minutes so that all of the heat generated can be utilised.

In order to prime the reaction, a quantity of calcium chloride (e.g. 10%) is added to the calcium oxide. The calcium chloride reacts immediately when contacted with water and it at once activates the reaction of the basic reagents used, for example, in the following quantities: calcium oxide 18 9 calories 501 3 calcium chloride 1.8 g calories 376 water 7.46 ml calories 5389 The calcium chloride is dispersed in the mass of the oxide; the percentages indicated are the best, as determined by experiment.

In fact, there is thus attained a consistency of response which does not depend on the manner in which the water reaches the reagent.

Nevertheless, in order to have a consistency of response the reagents have to have a grain size of approximately 20 mesh for calcium oxide, whereas the calcium chloride has to be powder.

Other chemical compounds have been tested to achieve the priming effect, but calcium chloride has been found to be the most convenient As previously indicated, the second disadvantage was that the reaction proceeds too rapidly. This disadvantage is obviated in accordance with this invention in the manner described below.

It should be noted first of all that one appropriate method for this purpose could be that of increasing the quantity of water provided to react. In fact, by increasing the mass of reagents the time required for its heating is prolonged. However, there would be a heat loss because of the necessity of having to heat all of the mass, and hence the volume of reagents would have to increase considerably.

These drawbacks are certainly not acceptable in practice.

In accordance with the invention, it has now been found that the addition to the reaction water of small quantities of organic substances, which are strongly hygroscopic or able to form viscous liquids with water, slows down the absorption of water by the reagent, calcium oxide, thus providing the desired retarding effect.

The hygroscopic substances found to be effective are numerous: derivatives of cellulose (carboxymethyl cellulose, methyl cellulose, etc.); derivatives of seaweeds (agar-agar, carragheen, alginates, etc.); soluble starch; and glycols and polyglycols.

Other substances, contrary to all expectations, have proven to be ineffective, for example such as polyvinyl pyrolidone.

The optimum compound was found to be ethylene glycol, since it is immediately soluble, acts at a low concentration (e.g. 1%) and does not ferment.

Therefore, according to the invention, the optimum formulation is as follows: calcium oxide 18 9 calcium chloride 1.8 g aqueous solution of ethylene glycol at 1% 8 ml.

If the container in which the operations take place comprises a body with two chambers, in one of which there has been placed a quantity of liquid to be heated extemporarily, for example equal to 40 ml, and the other one contains the mixture of the powders, it is possible for the heating to be achieved by adding to the powder the aqueous solution of ethylene glycol.

The whole assembly has to be insulated so as to prevent heat dissipation.

In the course of 30 to 50 seconds the reaction is in full progress and in 4 to 5 minutes a temperature of 700 is attained, if the starting temperature was 200.

If the starting temperature is much lower, the time required to attain a rise of 500 is greater.

If the starting temperature is much higher, the time required for the rise of 500 is less.

Therefore, the present invention has a specific subject-matter a self-heating, single-portion container for beverages and foods, in which the calories required are supplied by an exothermic reaction, characterised by comprising a first container, made of synthetic material, for the beverages or foods and closed at the top by a tear-off foil or sheet, a second container, made of metal, for the reagents and divided by a frangible partition into two zones, i.e. a lower zone which constitutes the reaction chamber which contains the solid reagents and an agent for priming the reaction, and an upper zone which contains the liquid reagents to which has been added a strongly hygroscopic substance capable of regulating the velocity of the exothermic reaction which takes place, when, as a result of rupture of said frangible partition, they come into direct contact in said reaction chamber.

The preferred solutions proposed in this invention for the reagents, for the priming agents and for those controlling the reaction rate have already been indicated above.

The invention will now be illustrated with reference to the accompanying drawings of one preferred form of embodiment, wherein: Figure 1 is a vertical section of the twin-chamber container according to the invention, ready for use; Figure 2 is a vertical section af the container in Figure 1 in the position in which the exothermic reaction occurs; Figure 3 is a vertical schematic section showing the essential parts of the container; Figure 4 is a view in vertical section of a detail of the connection between the main container for foods or beverages and the secondary container for the reagents; Figure 5 is a view in section of the rupturing element for breaking the frangible partition between the reaction chamber and the chamber containing the liquid reagents; Figure 6 is a view from below of the rupturing element in Figure 5;; Figure 7 is a side view of the plug for closing the container for the reagents, and Figure 8 is a view in vertical section of the outer beaker-like casing or shell for the thermal insulation of the container according to Figure 1.

With particular reference to the drawings, Figure 1 illustrates the container of unitary construction, according to the invention, formed by a main container 1 for the foods or beverages and made of plastics material, and a secondary container 2 made of metal, preferably of aluminium, for the reactive substances, these two containers being interconnected by intrusion on their contact surface 3.

This reagent container 2 has in its upper part a chamber 4 for the liquid reagents (water and reactioncontrolling agent) closed at the bottom by the frangible partition 5, on which the rupturing action of a rupturing element is exerted when this latter is urged upwards under the effect of a light external application of pressure. The container 2 contains in its lower part the solid reactive substance (CaO) and the priming substance (CaCI2). This container is closed at the bottom by the plastics plug 7, on which the external pressure is applied at the instant of use. The entire double-container structure is enclosed in a plastics, heat-insulating beaker-like casing 8 welded to the lower outer wall of the plug 7.

The container 1 is closed at the top by the tear-off foil 9.

Figure 2 illustrates the same container as in Figure 1, ready for use, but in the position attained after the external compression, the rupture af the frangible partition 5 and the penetration of the rupturing element 6 up to the upper wall of the chamber 4; the foil 9 having been torn off.

Figure 3 illustrates the basic details of the construction of the two containers, the connection of which is illustrated in the detail of Figure 4, corresponding to the rim point A, said connection being obtained by means of forming (moulding) by intrusion between the plastics material of the container 1 and the aluminium of the container 2 along their contact surface 3.

Figure 5 provides structural details of the rupturing element 6 of frustoconical shape and terminating in an upper cutting part 10, of which Figure 6 illustrates a view from below showing the circular ring shape of the base 11.

Figure 7 illustrates the closure plug 7 for the reagent container 2, on which are visible the horizontal ribs 12 and 13 which ensure its locking in the two operative positions indicated in Figures 1 and 2.

Finally, Figure 8 illustrates the entire beaker-like casing 8 made of expanded polystyrene and having a heat-insulating effect.

Production and utilisation of the container according to the invention are very simple.

The beverage or food to be heated extemporarily is introduced into the main container 1 made of plastics. Subsequently, it is tightly sealed with the foil 9.

The liquid reagent (water plus ethylene glycol) is introduced into the bottom of the secondary container 2 and it is closed with the frangible partition 5. Subsequently, there are introduced, likewise into the container 2, the rupturing element 6 and then the solid reagent (CaO+CaCI2). Closure is then effected with the plug 7 which is only partly inserted. A beaker-like casing 8 encloses the whole assembly so as to insulate it thermally. Preferably, the casing consists of expanded polystyrene.

In these circumstances, the container is in the position shown in Figure 1 and is ready for use. At this moment, only a slight pressure applied to the entire arrangement is required for the closure plug 7 to penetrate into the secondary, aluminium container 2, thus causing the rupturing element 6 to act on the perforable partition 5 and by penetrating up to the upper wall of the chamber 4 causing the liquid reagent to drop on to the solid reagent, thus initiating the exothermic reaction (Figure 2). The heat generated easily passes through the aluminium wall which heats up the useful contents.

Claims

1. A self-heating, single-portion container for beverages and foods, in which the required calories are supplied by an exothermic reaction, characterised by comprising a first container, made of synthetic material, for the beverages or foods and closed at the top by a tear-off foil, a second container, made of metal, for the reagents and divided up by a frangible partition into two zones, a lower one which constitutes the reaction chamber containing the solid reagents and an agent for priming the reaction, and an upper zone containing the liquid reagents to which a strongly hygroscopic substance has been added, capable of regulating the velocity of the exothermic reaction which takes place when, as a result of rupture of said frangible partition, they come into direct contact in said reaction chamber.

2. A self-heating, single-portion container for beverages and foods as claimed in claim 1, characterised in that said second container is accommodated in an inner cavity of the first container and is rigidly connected thereto over the entire surface of their contact by intrusion forming.

3. A self-heating, single-portion container for beverages and foods as claimed in claim 1 or claim 2, characterised in that a rupturing element is accommodated inside the reaction chamber, the lower end of the second container being closed by a plastics plug provided on its outer surface with two circumferential ribs which determine its position in an initial phase, in the course of industrial production, and in a final phase after application of the external manual pressure which causes, by displacement of said rupturing element upward as far as the inner upper surface of said second container, the rupture of the frangible partition.

4. A self-heating, single-portion container for beverages and foods as claimed in claim 3, characterised in that said rupturing element is of frustoconicai shape with its circular major base arranged lowermost in the interior of the reaction chamber and the minor base with a cutting point arranged uppermost.

5. A self-heating, single-portion container for beverages and foods as claimed in any one or claims 1 to 4, characterised in that the entire rigid, double-chamber structure is accommodated in a beaker-like casing made of thermally insulating material, welded to the outer lower surface of the closure plug of said metal container for the reagents.

6. A self-heating, single-portion container for beverages and foods as claimed in any one of claims 1 to 5, wherein said second metal container is made of aluminium.

7. A self-heating, single-portion container for beverages and foods as claimed in any one of claims 1 to 6, wherein said outer, beaker-like casing is made of expanded polystyrene.

8. A self-heating, single-portion container for beverages and foods as claimed in claims 1 to 7, wherein the solid reagent consists of CaO, the priming agent of CaCI2 in a quantity of up to 10%, and the liquid reagent of water mixed with a glycol or a polyglycol.

9. A self-heating, single-portion container for beverages and foods as claimed in claim 8, wherein said glycol is ethylene glycol.

10. A self-heating, single-portion container for beverages and foods as claimed in claim 9, wherein said ethylene glycol is present in a quantity of 1% in relation to the content of water.

11. A self-heating, single-portion container for beverages and foods as claimed in claim 10, wherein, for a quantity of 40 ml of foods or beverages to be heated, there are used 1 8 g of CaO, 1.8 g of CaC12 and 8 ml of an aqueous solution of ethylene glycol at 1%, for a total of 5389 calories.

12. A self-heating, single-portion container for beverages and foods as claimed in claims 8 to 11, wherein the grain size of the calcium oxide is 20 mesh and the calcium chloride is present in powder form.

13. A self-heating, single portion container for beverages and foods as claimed in claim 1 substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.