GB1576815A - Disposable container for use in heating foodstuffs - Google Patents

Description

PATENT SPECIFICATION

kt ( 21) Application No 18220/79 ( 22) Filed 11 Nov 1976 0 ( 62) Divided out of No 1 576 814 ( 31) Convention Application No 7 512 688 A_ ( 32) Filed 12 Nov 1975 in U ( 33) Sweden (SE) ( 44) Complete Specification published 15 Oct 1980 ( 51) INT CL 3 A 47 J 36/16 ( 52) Index at acceptance A 4 A 1 A 1 B 7 A 1 C 1 2 B 3 H 6 C 1 6 MX 6 N 7 A 2 A 4 D X B 8 K 2 KX WA ( 54) DISPOSABLE CONTAINER FOR USE IN HEATING FOODSTUFFS ( 71) I, HANS IVAR WALLSTEN, a Swedish citizen of, Chemin De La Lisiere 6, CH-1018 Lausanne, Switzerland, do hereby declare the invention for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following

statement: -

The present invention relates to a disposable container to be placed in a cooking vessel such as a saucepan for cooking foodstuffs, in particular by boiling and/or steaming.

When boiling food in cooking vessels it is usually impossible to avoid deposits on the floor and walls of the cooking vessel In certain cases these deposits are extremely difficult to remove by cleaning For this reason it is in many cases impossible to clean the cooking vessel in a satisfactory manner in, for instance, a dishwasher, and it is only with difficulty that it can be cleaned manually The deposits may also contain flavouring matter which tends to linger in the vessel, for instance as with potatoes, certain other vegetables and fish In the preparation of food containing fat such as sauces, purees and milk, a fat deposit is obtained on the inner surface of the cooking vessel, which also makes cleaning difficult.

Attempts have been made to place inserts of a disposable character in the cooking vessel, the insert consisting of aluminium foil, for example, being designed to be in contact with the inner wall and the bottom of the cooking vessel.

However, it has been found that for various reasons such an arrangement is not satisfactory.

In the first place water or other liquid may be trapped between the bottom of the vessel and the insert During heating this will rapidly vaporise and expand and may result in such violent expulsion of steam that the contents of the vessel may be partially expelled Secondly it is difficult to provide a suitable material which is resistant to heat but nevertheless has good heat transfer properties Good heat-resistance is necessary because extremely high local temperatures may occur on the insert due to direct contact with the cooking vessel Even if aluminium foil is used for the insert, which in itself has good resistance to heat and good thermal conductivity, it is difficult to fit this to the shape of the cooking vessel so that no pockets of air, steam or water are formed between the vessel and the insert This gives considerably reduced thermal conductivity and thus less economic heating Furthermore, unless coated with for instance a plastics material, aluminium foil is scarcely corrosion-resistant and is also sensitive to mechanical action If a hole appears in the foil due to corrosion or mechanical action, liquid will leak out between cooking vessel and insert, resulting in the expulsion of steam and air mentioned above.

If, on the other hand, the foil is coated with plastics, it loses its heat resistance and the plastics may burn because of the high temperatures which may occur.

According to the present invention there is provided a disposable container for use in heating foodstuffs, said container comprising a liquid-tight member of a thin flexible plastics material and having an open upper end and a continuous body portion, said body portion being sufficiently thin and flexible so that it is capable of being folded and crushed by hand to facilitate disposal of said container and that it needs to be supported in a reinforcing holder when being used for heating foodstuffs; and an annular semi-rigid flange integrally formed at said open upper end of said plastics member and extending generally outward and away from said body portion, said flange having an inner edge integrally formed with said body portion about the entire circumference thereof and said flange being sufficiently strong to maintain the shape of said flexible body portion when a foodstuff is deposited in said container.

( 11) 1576815 1,576,815 When preparing food by boiling, for instance, water is poured into a cooking vessel up to a suitable level and the flexible disposable container is arranged in the vessel and with the foodstuff to be cooked lying therein.

If the vessel is placed on a hot-plate, the water in the bottom of the vessel will be brought to the boil Steam will be produced and at least some of this steam will condense on the outer surface of the disposable container, the heat being transmitted through the wall of the container to the foodstuff If the level of the water is sufficiently high in the cooking vessel for it to come into contact with the bottom of the disposable container, heat may also be conducted directly through the disposable container, and any holder therefor which spaces the disposable container from the base of the vessel Some of the steam produced by the boiling water may also be directed over the upper edge of the disposable container so that the steam condenses directly on the foodstuff.

If water or other liquid leaks through a hole in the disposable container into the space between the insert and cooking vessel, there will be no risk of explosion because of the open-topped structure of the container Furthermore, heat-resistance properties of the material of the disposable container do not need to be exceptionally high since the disposable container, and the holder in which it is supported, are separated from at least the bottom of the vessel and thus the temperature of the walls of the disposable container will not therefore exceed 100 'C during cooking.

The invention will be more clearly understood from the following description which is given by way of example only with reference to the accompanying drawings in which:Figure 1 is a section through a first embodiment of apparatus including the disposable container of the invention; Figure 2 is a vertical section through a second embodiment of apparatus of the invention; Figure 3 shows the apparatus of Figure 2 as seen from above.

Figure 4 shows an enlargement of a part of the supporting holder casing shown in Figure 2; Figure 5 is a vertical section of a serving dish designed to receive a disposable container in accordance with the invention, supported in a holder; and Figure 6 shows a vertical section through a further embodiment of apparatus of the invention.

To boil the foodstuff, the cooking vessel 18 is placed on a hot-plate or some other source of heat As with traditional boiling, the water in the lower part of the vessel 18 should preferably be brought to the boil rapidly, that is to say with the hot-plate set at maximum heat.

During the heating process steam will gradually be produced by the water Initially, the steam will come into contact with the cooler wall of the flexible disposable container 23, whereupon the steam will condense thus liberating heat through the thin disposable container 23 to the water and the foodstuff.

As heat is supplied to the foodstuff, its temperature increases and a certain amount of excess steam circulates in the space between the disposable container 23 and the wall of the vessel 18 In the apparatus illustrated, some of the steam can pass over the upper rim of the disposable container and will also partially condense on the exposed surface of the water and the foodstuff so that the heat is also transferred in this manner Furthermore, as with traditional boiling, there will be a certain amount of condensation on the lid 25, which is preferably and as shown provided with a drip edge 26 in known manner As the heating process continues excess steam will find its way to the surroundings, as with traditional boiling, either by passing between the upper lip 28 of the cooking vessel and the corresponding edge of the lid 25 or through apertures provided in the vessel or the lid for this purpose.

As with the traditional boiling, an increasing quantity of excess steam reaching the surroundings indicates that the heating up stage is almost over and that it is advisable to reduce the rate of supply of heat By setting this at a lower level the quantity of excess steam can be kept down As described earlier, the quantity of water in the bottom of the cooking vessel 18 is small so that the surface of the water is below the bottom of the holder 21.

In this case the effect will be that of a heat pipe, steam from the water will condense on the surface of the disposable container and the condensate will then run back into the vessel 18 where it will once again be vaporised and the process repeated Assuming that the disposable container has good thermal conductivity, being made of a suitable thin material, considerable heat can be rapidly transferred from hotplate to foodstuff However, it has also been found that the water level at the bottom of the vessel may be so high that the disposable container may be partially immersed, without detracting from the heating and cooking processes However, if the water level is too high the thin disposable container may be disturbed by vigorously boiling water and start vibrating in the casing which may be a drawback in certain cases.

The process takes place under a lid 25 in order to reduce the heat losses, especially if the space between the disposable container 23 and the wall of the cooking vessel is large.

When cooking is complete the combination of holder 21 and disposable container 23 may be lifted out of the cooking vessel 18, for instance with the help of a separate handle.

3 1,576,815 The unit consisting of the disposable insert 23 and the holder 21 may now be placed directly on the table for serving However, the disposable container alone or the combination of holder and container may also be placed in an outer bowl which can have a lid and is shaped to receive the disposable container or the unit If the food is not all consumed, either the disposable container alone or the complete unit may be used as a storage container for the left-over food, for instance in a refrigerator or freezebox Leftovers stored in this manner can then be placed in the cooking vessel and reheated to serving temperature, using a smaller quantity of water, upon a later occasion.

Since the disposable container consists of a thin-walled material which in itself does not have particularly good mechanical properties such as stiffness, or even have high heatresistance, it is possible to mass-produce the disposable containers inexpensively Since also an inexpensive plastics film can be used, disposable containers manufactured in this way can be readily disposed of after use The disposable container may be given an appropriate shape in relation to the holder at the time of manufacture One suitable construction of the disposable container is in the shape of a bowl or trough manufactured by means of hotforming, for instance vacuum-forming, of plastics film Such disposable containers have the advantage that they can be made relatively stiff at the top, to facilitate handling.

Irrespective of whether the disposable container 23 and holder 21 are to be used for preparing food storing food or heating up food, therefore, the disposable container can be thrown away after use since it can be made so cheaply The cooking utensils need not therefore be cleaned after use, nor of course the serving dish in which the disposable container or the unit is placed for serving or keeping the food It has been found that many cooking operations can be performed in the same cooking vessel without the vessel having to be washed This is a great help in the housework, particularly when preparing dishes which tend to leave deposits on the walls of the cooking vessel which are difficult to remove.

As will be described below, the cooking time and energy consumption is approximately the same when using the apparatus according to Figure 1 as compared with traditional cooking Burning does not occur, presumably because the surface temperature of the insert never exceeds 98-99 C or thereabouts As is known, burning is usually caused by the foodstuff being heated locally to a high temperature It has been found that milk, drinking chocolate, vegetables and fish boiled by the method of the invention do not boil over It has also been found that eggs have less tendency to crack 65 Furthermore, it has been found that by using the apparatus of Figure 1, vegetables and fish, for instance, can be steamed The foodstuff is in this case placed in the insert without water and cooked with the lid on 70 Steam will then find its way between the unit and the wall of the cooking vessel and pass over the upper edge of the unit to condense on the walls and the surface of the foodstuff.

Thus, not only is the advantage gained that 75 the cooking vessel is not dirtied by using the insert, but at the same time the advantages associated with steaming certain foodstuffs are also obtained, namely that the flavour is retained better Steaming generally takes 80 somewhat longer than boiling in accordance with the method described above, however.

Figure 1 shows one embodiment of the invention The cooking vessel is designated 18 and has a support means 19 having an upper 85 edge 20 arranged therein The support means 19 may comprise a number of legs made of sheet-metal, for instance, which are bent upwardly and inwardly as shown in Figure 3.

The holder 21, preferably consisting of a 90 wire basket or a perforated material, has a flange 22 directed outwardly and downwardly, this flange being designated 22 The flange is arranged to rest on the edge 20 of the support leg The flange 22 of the holder 21 is also 95 perforated or consists of mesh so that steam can pass through it The holder 21 with its flange is positioned centrally in the vessel 18.

A disposable plastic container 23, intended for use once only, is placed in the holder 21 100 In the embodiment shown in Figure 1 the disposable container 23 has a flange 24 which fits at least partially over the flange 22 of the casing 21 A lid 25, preferably provided with a drip edge 26 is placed on the cooking 105 vessel 18 In this case also the thin disposable container 23 is suitably provided with one or more pouring lips One such pouring lip is designated 27 in Figure 1 Since the disposable container 23 is made of a thin, flexible 110 plastics material, the pouring edge 27 can be shaped to fit the drip edge 26 of the lid 25 to form a seal between the flange 28 of the cooking vessel and the corresponding outer edge of the lid 25 115 Water is poured into the vessel 18 to a suitable level Heating up and boiling occurs both by means of heat transfer by steam condensing in the disposable container 23 and also possibly by heat conducted directly from the 120 water at the bottom of the cooking vessel 18 to the holder 21 and the disposable container 23 suspended in the vessel 18.

When preparing purees and sauces it is often necessary to beat the mixture either 125 during or after cooking Difficulties would arise if there were no flange 24, especially as the disposable container is very thin and 1,576,815 R 1,576,815 flexible, in that the disposable container with its contents might be drawn in during the heating operation so that the disposable containe, 23 loses contact with the mesh holder 21 This may result in the disposable container 23 folding down into the mixture which would then spread over the container rim and be spoiled and dirty both the holder and the cooking vessel The Figure 1 embodiment of the present invention has the advantage that the flange 24 holds the top of the disposable container in contact with the flange 22 of the holder 21 thus permitting vigorous stirring or beating In the illustrated embodiment it is preferable for the disposable container and also the holder to be designed so that several of them can be stacked one inside the other Thus, in the Figure 1 embodiment it is advisable for the flange 24 to be shaped so that the disposable containers can be stacked.

Figure 2 shows another embodiment of the invention A holder 29 is arranged in a cooking vessel 28, a flange 30 of the holder fitting over the upper part 31 of the vessel 28 A disposable container 32 is placed in the holder 29 The disposable container 32 also has an upper flange 33 which fits over the flange 30 of the holder 29 The holder 29 is perforated and at least the lower part preferably consists of a mesh basket of suitable material.

The flange 30 of the holder 29 may consist of homogeneous material, but in this case steam apertures 34 are provided at least at certain points in the holder Holes or slits 35 are suitably arranged in the same manner at the top of the disposable container 32, this also being designed so that the slits 35 can easily be positioned over the steam apertures 34.

Figure 3 shows the apparatus of Figure 2 from above The upper flange 30 of the holder 29 forms two projections 36 and 37, which protrude over the flange 31 of the cooking vessel 28 and provide handles for lifting the holder 29 Suitably, and as shown in Figure 2, the handles are provided with a heatinsulating section 38 The disposable container 32 can be similarly extended from the flange 33 so that the handle 36 is covered by the thin material of the disposable container (see 39, Fig 2) The embodiment shown in Figures 2 and 3 has certain advantages over the Figure 1 embodiment Due to the shape of the holder 29 no separate support means or centering means is required to position the holder 29 in the vessel 28 With the aid of the protruding handles 36, 37, which constitute extensions of the holder 29, the holder can easily be lifted out of and into the vessel 28 without the necessity of a separate handle With the aid of the flanges and 33 on holder 29 and the flexible disposable container 32, respectively, the disposable container 32 will be retained at the upper edge of the holder 29 during stirring.

Since the disposable container 32 fits over the 65 flange 30 of the holder 29 and also over the flange of the cooking vessel 28, the contents can be poured out without risk of dirtying the vessel 28.

The flanges on the disposable containers 70 stiffen the upper part of the containers making them easier to handle and lift into and out of the holder when they already contain the foodstuff In certain cases, therefore, the disposable container with the foodstuff can be placed on 75 a suitable surface without the holder being used In this case the extending parts 39 of the disposable container can be used as handles.

Figure 4 shows a detail of the holder 29.

The upper edge, with the flange 30, is pro 80 vided with steam apertures 34 as mentioned previously The rest of the holder consists of a mesh 40 of suitable material, relatively stiff in comparison with the disposable container.

Since the disposable container 32 is also pro 85 vided with protruding parts 39 corresponding to the handle 36 in the holder it is easy to guide the disposable container to such a position that the apertures 35 in the disposable container 32 communicate with corresponding 90 steam apertures 34 in the holder 29 The apparatus shown in Figures 2 and 3 can be provided with a lid in suitable manner.

As mentioned earlier, it is preferable that at least the holders 29 are shaped so that they 95 can be stacked into each other for storage.

Since the disposable containers 32 with their holders can be used not only for cooking, but also for storing and serving food, there must be several holders to fit one size of saucepan 100 in every household Thus the holders are designed so that they can be stacked inside each other to require a minimum of space As shown in Figures 1, 3 and 4, both the disposable container and the holder have been 105 made slightly frusto-conical in their side wall regions to facilitate stacking.

The disposable containers can also be used for storing food prepared earlier, as mentioned above Figure 5 shows a means for 110 serving or storing food using the same disposable container as previously used for preparing the food The disposable container 32 shown in Figure 5 with the holder 29 or 40 has the same shape as that pre 115 viously shown in Figures 2 and 3 The disposable container 32 with the holder 40 is in Figure 5 placed in a bowl-shaped outer dish 41 Because the bowl is suitably shaped, the flexible disposable container 32 120 with its holder will remain suspended by its flange and centred in relation to the bowl wall so that a space 42, 43 is formed This provides good heat-insulation A lid 44 is placed on the dish 41, preferably having a handle 45 The 125 dish 41 is preferably also shaped so that several dishes can be stacked one into the other The lid 44 should also preferably be 1,576,815 stackable In the embodiment shown, furthermore, another dish 41 with its contents can be stacked on top of a similar serving dish with lid 44 if the bottom of the dish is provided with a raised section 46 fitting into the handle 45 of the lid below Of course, the method of stacking shown here is only one example, out of many possible embodiments In many cases it is convenient for the disposable container without a holder to be placed in a dish with lid, designed to fit the shape of the disposable container, for instance for serving or storing after cooking This dish may be double walled to provide good heat insulation The inner wall of the storage dish may possibly be perforated or consist of mesh.

Thus in a complete system using the disposable container according to the invention for preparing, keeping, serving and reheating food, one and the same disposable container can be used The system is exemplified in the following manner referring to the apparatus of Figures 2, 3 and 5.

A suitable cooking vessel for preparing food is taken, together with an appropriate holder and disposable container The disposable container is lowered into the holder in such a way that the steam apertures cover each other.

The unit consisting of holder and disposable container is placed in the cooking vessel after a suitable quantity of water has been poured into the vessel The food to be cooked is placed in the disposable container The lid is then placed on the cooking vessel and the boiling process is initiated, being performed as described above The quantity of heat is thus regulated according to how much excess steam escapes between the edge of the lid and the vessel or through special holes in the lid.

In the embodiments according to Figures 2 and 3 cooking may also be performed without the lid since the steam losses will be relatively small assuming that the steam apertures are not too large.

When food is ready it can, of course, be served straight from the cooking vessel Hlowever, for many reasons it is preferred to use the storage and serving system proposed In this case the unit 29, 32 is for instance lifted out of the cooking vessel 28 shown in Figure 2 and placed in the storage and serving dish 41 shown in Figure 5 If the food is not to be consumed immediately it should be covered with the lid 44 The lid 44 may possibly be provided with extra heat insulation It has been found that newly cooked food can be kept hot for a relatively long time in the outer dish 41 described in Figure 5.

If the food in the dish 41 is only partially consumed, the dish together with unit 29, 32 and contents can be used for storage in a refrigerator or deep-freeze If the food is to be reheated, the unit 29, 32 is lifted out of the outer dish and once again placed in a cooking 65 vessel, after which the food can be quickly reheated as described earlier The unit 29, 32 can then once more be lifted out of the cooking vessel and placed in the serving dish When the food is consumed the disposable container 70 32 is removed from the holder 29 and thrown away.

Thus, as described above, the thin, disposable container has protected the cooking vessel from becoming dirty during preparation 75 of the food as well as protecting the storage dish from becoming dirty during serving and if stored The cooking method, made possible by the use of inexpensive, thin, flexible disposable containers which need to be streng 80 thened and stiffened by being combined with a casing permeable to steam and water, assures that the foodstuff will be kept in the same disposable container during preparation, storage and serving This not only avoids cleaning 85 the cooking vessel, but also cleaning the storage vessel Furthermore, there is less waste since the foodstuff does not have to be transferred from one vessel to another.

In the embodiments described so far water 90 is poured into the bottom of a traditional cooking vessel in order to cook foodstuff by steaming when heat is applied Other methods and means for cooking are of course possible using the dis 95 posable container of the present invention.

It is, for example, possible to use means other than those described for applying heat and producing steam The food can be cooked in special cooking apparatus which can be auto 100 mated to a certain extent in order to facilitate the cooking process Figure 6 reveals such a device This Figure shows a cooking vessel 47 placed on a hot plate 48 and housing a holder 49 similar to the holder 29 described 105 previously A disposable container 50 according to this invention is placed in the holder 49 A lid 51 fits over the vessel 47 The base 52 of the cooking arrangement according to Figure 6 includes a means for producing steam 110 This is not shown in Figure 6 but may comprise an electric coil of the type employed in automatic coffee-making machines A container 53 for liquid is placed above the steam generator A steam channel 54 provided with 115 a suitable connection at 55 directs steam to the space between the wall of the vessel 47 and the holder 49 The steam produced is con.

densed while at the same time transmitting heat to the outer surface of the disposable con 120 tainer 50 Steam also passes through apertures in the disposable container to heat the food to be cooked.

The condensate runs down to the bottom of the vessel 47 and is vaporised again by the 125 heat from the plate 48 The device is preferably provided with a dispensing means for the continuous supply of water and steam in 1,576,815 adjustable quantities The device is also preferably provided with a timer and thermostat.

The latter can be set in suitable manner so that a suitable rate of vaporisation is obtained from the bottom of the cooking vessel The advantages obtained with an arrangement like the one shown in Figure 6 include the fact that the cooking process can be automated by using the thermostat and time-setter Furthermore, the water is brought to the boil quickly since the quantity of water is adjusted to the capacity of the vaporiser and vigorous production of steam will be obtained shortly after the machine is started The water supply to the vaporiser may be controlled by a timer.

The use of a thermostat combined with the vaporiser prevents boiling dry Instead of a timer to control the water supply, the quantity of water poured into the container 53 may be adjusted to the desired cooking time This can easily be achieved since the water container 53 is preferably transparent and marked with graduations.

The device shown in Figure 6 is only one example of the many ways of making use of the great advantages gained by the use of thin, disposable containers according to the invention combined with the reinforcing holder.

It has been mentioned earlier that the disposable containers should be liquid-tight and have good thermal conductivity.

A plastics film used for making the flexible disposable containers must be suitable for contact with foodstuff It has been found that satisfactory results can be obtained using disposable containers made of plastics such as polyolefins, polystyrenes, styrene/butadienes, PVC, all of which are suitable for hotmoulding provided good heat-conductivity isensured by making the disposable container sufficiently thin Disposable containers have been made from HD-polyethylene by means of hot moulding, for instance, with very good results It has been found that a special type of HD-polyethylene, namely, a so-called HD-HM-polythene (High Density Hot Moulding) has given extremely satisfactory results since the material is suitable for hot moulding and the walls can be made extremely thin so that the disposable container will easily crumple up after use so that the used container does not take up much space A disposable container can be made in this material which has a wall-thickness of about 0 01 mm at the thinnest part Conventional moulding technique of course enables adjustment of the wall-thickness of the disposable container to its function so that the upper flange of the disposable container is slightly thicker to pro 60 vide a certain stiffness A wall-thickness as thin as 0 01 to 0 06 mm offers great advantages in the form of good thermal conductivity, small quantity of raw material and easy compressibility upon disposal 65 Good thermal conductivity is also obtained with disposable containers manufactured by hot-moulding since the side walls of the disposable container body portion are smooth and better thermal conductivity is obtained than 70 could be obtained, for example, with a pleated aluminium foil wall The advantage of a thin flexible disposable container is of course not only that of good thermal conductivity It is important that the disposable container is 75 inexpensive and since the cost of material is a major part of the manufacturing costs for disposable containers, a thin container is also desirable from the cost point of view A third advantage is also gained, as mentioned, and so that is that if the disposable container is thin it can easily be crushed when thrown away, so that it occupies very little space in the refuse bin.

HD-polyethylene has previously been men 85 tioned by way of example as suitable for disposable containers made by means of hotmoulding This is, however, only one example Many other plastics materials suitable for moulding to the desired dimensions can 90 also be used within the scope of the invention.

When vacuum-forming a thin plastics film, for example, it may also be advisable for the disposable container to have greater thickness at the upper edge than at the bottom and the 95 lower portions of the sides In this case the advantages of good thermal conductivity, low weight and easy crushability are obtained while at the same time the upper edge is given a certain stiffness since the material is thicker 100 there as well as being reinforced by the formation of the semi-rigid flange The stiffness in the upper edge facilitates handling of the disposable container.

As emphasised previously, it is important 105 that the disposable containers do not weigh too much, not the least from the cost point of view It may be mentioned that disposable containers having a volume of 1 litre which were manufactured for various materials were 110 found to have the following weights:

1,576,815 Initial Thickness, Material mm Weight, g Vacuum-formed polypropylene 0 45 11 0 Vacuum-formed polythene 0 18 4 5 Vacuum-formed polythene O 15 3 7 Vacuum-formed polythene 0 09 2 3 Polythene bag having a stiff upper flange 0 02 1 5 As mentioned earlier, extensive studies have been made in preparing food by boiling using the disposable container in accordance with the invention The studies have also covered comparison with boiling in water in the traditional manner Steaming has also been tried, that is to say without liquid in the disposable container In all cases the foodstuff was cooked using the same boiling programme for both the traditional boiling and the use of the disposable container in accordance with the invention Samples were then taken and the result tested Testing was both visual and by taste Sampling was performed by a jury who gave their verdicts without knowing the manner in which the food had been cooked The result showed that potatoes, vegetables, meat and fish, i e, food requiring relatively long cooking times, did not differ in the cooking time according to the invention or for traditional cooking In the preparation of food requiring only a short period of heating up, such as readymade soups or boiling eggs, slightdifferences in cooking time have been observed, i e, it has taken slightly longer with the disposable container according to the invention However, the differences are such that they must be considered insignificant in comparison with the great advantages gained by use of the disposable container according to the invention It has been found that deepfrozen foods can be thawed by placing them in the disposable container and then heating them by means of steam from the water in the bottom of the cooking vessel, for instance.

An extra high supply of heat should be used for quick thawing Due to the great temperature differences between the cold food and the steam, considerable quantities of steam will be condensed, thus resulting in rapid thawing.

Also included in the system for preparing, serving and storing food is the deep-freezing of goods in a mould shaped to resemble the contour of the thin disposable container so that when placed in the disposable container, preferably having removed wrapping applied for deep-freezing, the deep-frozen product has good contact with the walls of the container body portion to facilitate thawing In certain cases, the food can be frozen and stored directly in disposable containers which can then be placed in the holder for thawing and possibly also preparing, serving and keeping in the same disposable containers.

Experiments have unexpectedly shown that when using disposable containers of extremely thin plastics film, a temperature-time chart can be obtained which, with respect to the cooking process, coincides with the corresponding temperature-time chart for traditional boiling.

Various aspects of the cooking process and of the apparatus disclosed herein are also described and claimed in my co-pending British Patent Application No 47068/76 (Serial No.

1,576,814).

Claims (11)

WHAT I CLAIM IS: -

1 A disposable container for use in heating foodstuffs, said container comprising a liquidtight member of a thin flexible plastics material and having an open upper end and a continuous body portion, said body portion being sufficiently thin and flexible so that it is capable of being folded and crushed by hand to facilitate disposal of said container and that it needs to be supported in a reinforcing holder when being used for heating foodstuffs; and an annular semi-rigid flange integrally formed at said open upper end of said plastics member and extending generally outward and away from said body portion, said flange having an inner edge integrally formed with said body portion about the entire circumference thereof and said flange being sufficiently strong to maintain the shape of said flexible body portion when a foodstuff is deposited in said container.

2 A disposable container according to Claim 1, wherein said body portion is thermoformed into a substantially bowl-shaped configuration so that said body portion includes a side wall and an integral bottom, said inner edge of said flange being integrally formed with said side wall.

3 A disposable container according to Claim 8 1,576,815 8 1 or 2 wherein said container is shaped so as to be insertable in a holder in a cooking vessel so that the said side wall and integral bottom of the container body portion smoothly conform with a side wall and a bottom of said holder.

4 A disposable container according to Claim 3, wherein said side wall is generally conical in shape to facilitate stacking.

5 A disposable container according to Claim 2, 3 or 4, wherein said flange formed at said open upper end of said plastics member body portion has a thickness greater than said side wall and integral bottom to further strengthen said plastics member.

6 A disposable container according to any one of the preceding claims, wherein said flange has a downwardly extending free end surrounding at least a major portion of the circumference of said flange.

7 A disposable container according to any one of the preceding claims, wherein said liquid-tight plastics member is formed irom a polyolefin.

8 A disposable container according to any one of the preceding claims, wherein said liquid-tight plastics member has a thickness of between 0 01-0 18 mm.

9 A disposable container according to Claim 7 wherein the thinnest part of said body portion has a thickness no greater than 0.06 mm.

A disposable container according to any one of Claims 1 to 8 wherein said liquidtight plastics member is thermoformed from a sheet of plastics material whose thickness is substantially 0 18 mm.

11 A disposable container according to any one of the preceding claims wherein a pouring lip is formed in said flange.

J A KEMP & CO.

Chartered Patent Agents, 14 South Square, Gray's Inn, London WC 1 R 5 EU.

Printed for Her Majesty's Stationery Office by the Courier Press, Leamington Spa, 1980.

Published by the Patent Office, 25 Southampton Buildings, London, WC 2 A l AY, from which copies may be obtained.

1,576,815