Insertable Thermotic Module for Self-Heating Can
A self-heating container having a container body with an internal beverage section and a thermic cavity. A liquid reactant is positioned in a first section of the thermic cavity and a solid reactant is positioned in a second section of the thermic cavity. The solid reactant may be an amount of CaO ranging from about 80 to 99 percent by weight combined with a wax based inhibitor ranging from about 1 to 20 percent by weight. The wax based inhibitor has a melting point ranging from above 100° C. to about 120° C.
This application claims the benefit under 35 USC § 119(e) of U.S. Provisional Application No. 61/119,549, filed Dec. 3, 2008. This application also is a continuation-in-part of U.S. Ser. No. 12/023,093 filed Jan. 31, 2008, which is a continuation of PCT application number US2006/29577, filed on Jul. 28, 2006, which claims priority to U.S. Provisional Application Ser. No. 60/704,471, filed on Aug. 1, 2005, which further claims the benefit of U.S. Provisional Application Ser. No. 60/915,848, filed on May 3, 2007. All of the above applications are incorporated by reference herein in their entirety.
FIELD OF INVENTIONThe present invention relates to self-heating (or self-cooling) cans or other containers holding beverages, food, medicine, epoxy resins and other materials that it is desired to heat (or cool) before consuming or using. In particular, the present invention relates to an improved thermic module for such self-heating (cooling) containers.
BACKGROUND OF INVENTIONContainers may have integral or separate insertable modules for warming materials in the container, such as Japanese sake, coffee, or soup. Examples of such self-heating containers with integral thermic modules are disclosed in U.S. Pat. Nos. 5,461,867 and 5,626,022, issued to Scudder et al and an example of a separately insertable module is disclosed in U.S. Pat. No. 6,134,894 to Searle, et al. Such containers typically include an outer can or body, in which the food or beverage is sealed and an elongated cavity or chamber which extends into the container body from the bottom end. The cavity is sized to accommodate the thermic module. The thermic module normally contains two chemical reactants which are stable when separated from one another, but when mixed in response to actuation of the thermic module by a user, produce an exothermic reaction (or, alternatively, an endothermic reaction) and thereby heat (or cool) the contents of the container. This elongated cavity functions as both a chamber in which to contain the reaction and a heat-exchanger for transferring heat between it and the surrounding contents of the container body.
The thermic module usually has two chambers, each of which contains one of the chemical reactants, separated by a breakable barrier such as metal foil. Typically, one of the reactants is a liquid, and the other is in a powdered or granular solid form. Calcium oxide (quicklime or CaO) and water are examples of two reactants known to produce an exothermic reaction to heat the container contents. Other combinations of reactants (e.g. ammonium nitrate and water) produce endothermic reactions to cool the container contents. The bottom of the thermic module cavity is normally closed off by an end-cap. The outside of the end-cap will serve as an actuator button that a user may depress to initiate the heating or cooling. The end-cap typically has a pushrod or similar prong-like member that extends from the actuator button nearly to the breakable barrier. Depressing the actuator button forces the prong into the barrier, puncturing it and thereby allowing the reactants to mix.
The heat produced by the resulting exothermic reaction (or, alternatively, used by a resulting endothermic reaction) is transferred from the reaction chamber of the thermic module to the contents of the container body by conduction. The end of the container body opposite the cavity has a seal or closure, such as conventional beverage container pull-tab or pop-top, which may be opened and through which the user may consume the heated or cooled contents.
In the embodiment shown, the area of internal cavity 10 above cup 15 will house a solid reactant and a cup 15 will serve as a liquid reactant cup. A breakable barrier 24 will separate the interior space of liquid reactant cup 15 from the area of internal cavity 10 above cup 15. In the embodiment shown, breakable barrier 24 will be formed of a metal (such as aluminum) foil material approximately 10 μm to 60 μm thick and more preferably 20 μm to 40 μm thick. It will be understood that a punch member 23 may be moved upward by a user (as explained in more detail below) in order to puncture breakable barrier 24 and allow the solid and liquid reactants to mix.
The bottom portion of container 1 will accommodate the means for puncturing breakable barrier 24 and allowing the solid and liquid reactants to mix. These elements located in the bottom portion of this embodiment of container 1 generally form the “thermic module” when charged with reactants and are seen individually in the exploded view of
Viewing
The external features of liquid reactant cup 15 are best seen in
The assembly of the various components in the lower portion of body 2 is best seen in
When the components of container 1 are assembled as illustrated in
In a preferred embodiment, the side of breakable barrier 29 which faces end cap 32 will be have a distinct coloration (for example red) which will allows breakable barrier 29 to be easily visible through the sections 34 of removed material in center portion 33. This will allow easy visual inspection of breakable barrier 29 through sections 34 to ensure breakable barrier 29 is still intact prior the initiation of the heating reaction. If breakable barrier 29 is not intact, the user is alerted to the possibility that the self-heating container has been damaged or may not be in working order.
Viewing
It will be understood that when the heating module is in its assembled state, cutting projections 36 are positioned very close to (almost contacting or barely contacting) breakable barrier 29. In addition to breaking through barrier 29 upon activation by a user, this allows cutting projections 36 to act as a safety mechanism should breakable barrier 24 fail and allow the liquid and solid reactants to mix. If a user has not activated the thermic module, barrier 29 will be intact and will contain the pressure buildup within the module due to the mixing reactants. If barrier 29 is not broken while the initial pressure in the module is low, the pressure may increase sufficiently to cause a dangerous explosion of the container. However, because barrier 29 is positioned quite close to cutting projections 36, even low pressure from the initial stages of the reaction will press barrier 29 against cutting projections 36 and cause them to tear barrier 29. Thus, pressure is never allowed to reach dangerous levels within the thermic module.
In one embodiment of the present invention, the liquid reactant will be water and the solid reactant will be a “quick lime” or CaO based mixture. The solid reactant may be a mixture of CaO and a granular or powdered wax which will act as a reaction inhibitor to slow the reaction rate. In a more preferred embodiment, the wax will be a palm oil based wax with melting point above 100° C. One illustrative example is a wax designated SW-10 and supplied by Suka Chemicals, Sdn Bhd of Selangor, Malaysia. More preferably, the wax will have a melting point of ranging from above 100° C. to about 120° C., and still more preferably, ranging from about 105° C. to about 115° C. Also in a preferred embodiment, the wax will be in the form of granules having a size of approximately 0.5 mm. In one preferred embodiment, the solid reactant will comprise CaO content ranging from about 80 to 99 percent by weight and a wax content ranging from about 1 to 20 percent by weight, and more preferably a CaO content ranging from about 95 to 98 percent by weight and a wax content ranging from about 2 to 5 percent by weight. Alternatively, the solid reactant could comprise a CaO content ranging from about 90 to 96 percent by weight and a wax content ranging from about 4 to 10 percent by weight. In certain embodiments, for example where the liquid reactant is water, the ratio of water volume to solid reactant weight could be about 0.25 to about 0.5 with one preferred embodiment being about 0.35.
As one example, in a container where 210 ml of beverage is being heated, the solid reactant could consist of 80 grams of CaO and 3 grams of the above described wax. Naturally, the above percentages of CaO are only approximate and factors such as impurities in the CaO or different types of waxes may result in mixtures outside of the above stated ranges or wherein the combined weight percentages of CaO and wax are less than 100%. In one preferred embodiment, a very low moisture content CaO will be employed with the CaO having been vacuum packed soon after exiting the kiln.
One experiment found that the above reactant combination of 80 grams of CaO and 3 grams of wax when combined with 27 ml of water in the above described thermic module will cause an increase in the temperature (delta T) of 210 ml of a water based beverage (located in beverage space 6) to at least above 50° C. and more commonly to about 55° C.
In a preferred embodiment, some printing may be written on the inner surface of shrink wrap film 40 with thermographic ink or may be applied to certain areas of the can such as the can lid. Thermographic ink changes colors upon reaching a predetermined temperature. In this manner, certain areas of the can could change color when the contents of the can have reached a temperature which is considered to be sufficiently hot. As an example,
Naturally, the thermographic ink could take on any design and could be formulated to change color over any given range of temperatures. For example, with infant baby formula the ink might change color at approximately 40° C. to indicate the beverage is ready to drink as opposed to the approximately 65° C. for an adult beverage. More preferably, when dealing with drinks for infants, the first color indication could take place at approximately 37° C. to indicate a suitable drinking temperature and a second color indication could take place at approximately 43° C. to indicate the drink was too hot for infants to drink. For adults, the first color indication could take place at approximately 60° C. to indicate a suitable drinking temperature and a second color indication could take place at approximately 80° C. to indicate the drink was too hot to drink. Naturally, variations of these temperature ranges are within the scope of the present invention. Additionally, the present invention encompasses the first and second indicators not only being true “colors” such as red and green, but also the indicators being different shades of a single color including different shades of gray and even the ink changing from opaque to transparent or some particular color. The term “color” as used herein is intended to encompass all these alternatives. For example, in the embodiment suggested in
Another embodiment of the present invention includes a container having a thermotic module and a label attached to a surface of the container, the label comprising an ink which gives an indicia when said thermotic module has been activated. One purpose of such a label is to indicate whether the thermotic module has been activated in order to assist consumers in identifying containers which may have previously been activated but not otherwise opened. In preferred embodiments, the ink is irreversible so that once the container has been activated, the indicia remains permanently visible even after the container has cooled to ambient temperatures.
The ink forming the indicator is a type of ink which changes states based upon the occurrence of some condition. As used herein, “ink” means any substance, usually a liquid but possibly a gas or solid, which is used to impart color to another material. For example, many embodiments employ a thermochromatic ink which changes color or otherwise becomes visible when a certain temperature range is reached.
In one embodiment, the ink comprises a leuco dye, i.e., a dye whose molecules can acquire two forms, one of which is colorless. One nonlimiting example of leuco dye based thermochromatic inks are available from New Prismatic Enterprise Co. Ltd of Taipei, Taiwan. In preferred embodiments, the indicator becomes visible when the label reaches about 40 degrees Celsius and more preferably when the label reaches about 60 degrees Celsius. However any temperature or range of temperatures at which food or beverages could be consumed (e.g., 0 degrees to 100 degrees Celsius or any temperature of range therebetween) could be designed as the activation temperature for the ink.
The size and shape of the label could vary greatly from application to application. In
Nor is it necessary that the irreversible thermochromatic ink be printed on a separate section of material in order to form the label. In certain embodiments, the irreversible ink could be printed directly on the container (for example the container lid as suggested in
To this end, a removable plug is formed over nursing aperture 45. In the embodiment seen in the figures, the removable plug consists of a pull tab 55 integrally formed with attachable nipple 45. Where the lower section of the pull tab 55 attaches to nursing aperture 49, a v-shaped cut is produced through nipple head 46 such that only a thin section of material holds tab 55 to nipple head 46. This produces a fault or fatigue point along which tab 55 will break off. When tab 55 is pulled, it readily tears away or twists off and leaves aperture 49 open to fluid flow induced by an infant's suckling. All the features of nipple attachment 45, including v-shaped cuts and pull tabs 55, may be integrally formed by any conventional technique such as pour molding or injection molding of silicon.
A second aperture, air aperture 53, is also formed in the shoulder portion 48 of nipple attachment 45. Air aperture 53 is closed with a removable plug 54 in the same manner as nursing aperture 49. The purpose of air aperture 53 is to allow air into container 1 to displace fluid removed through the infant's nursing and prevent a vacuum from forming in container 1. Naturally an air aperture could be positioned anywhere on the container which would allow air to replace the fluid removed.
Connecting nipple attachment 45 to container 1 may be accomplished as follows. Nipple attachment 45 will have an attachment perimeter which is sufficiently large in diameter in order to stretch across the container rim. The lid rim will then be placed over the attachment perimeter and the container rim and the lid rim will be crimped into place. It will be understood that when the rubber-like material is tightly crimped between the container rim and the lid rim, it will form an air-tight seal for retaining and sealing in the contents of container 1.
When nipple attachment 45 is used in combination with container 1, a plastic rim cap or protective ring 5 (see
In a preferred embodiment, container 1 will include some type of easy-opening lid 3, such as a conventional lid having a rim, a peel-back top, and a finger ring as suggested in
It will be seen that placing nipple attachment 45 in the folded position within container 1 allows it to be sealed therein by the lid as suggested by
The present invention will further include a novel lip protector 60 as seen in
The present invention also includes a method of retorting a self-heating container. “Retorting” is a conventional process of sterilizing the contents of a canned goods and the like. Retorting typically comprises subjecting the contents of a sealed can to elevated temperatures (about 120° C.) and pressures (about 10 psi). The method begins with the step of providing a metal container 1 (see
While the present invention has been described in terms of specific embodiments, many variations and modifications will be apparent to those skilled in the art. For example, the reactants in the above embodiments were CaO and water, but other reactants are within the scope of the present invention. Likewise, while wax is disclosed as the temperature moderating substance in the above embodiments, any substance maintaining the reaction temperature at between about 105° C. and about 120° C. is within the scope of the present invention. All such modifications and variations are intended to come within the scope of the following claims.
Claims
1. A container having a thermotic module and a label attached to a surface of said container, said label comprising an irreversible ink which gives an irreversible indicia when said thermotic module has been activated.
2. The container according to claim 1, wherein said irreversible ink is a thermochromic ink.
3. The container according to claim 2, wherein said indicia comprises lettering formed by said irreversible ink.
4. The container according to claim 2, wherein said indicia comprises the negative image of lettering formed by said irreversible ink.
5. The container according to claim 2, wherein said irreversible ink is a thermochromic leuco dye ink.
6. The container according to claim 2, wherein said label comprises a PVC film and said ink is printed on a surface of said film which attaches to said container.
7. The container according to claim 2, wherein said label comprises said ink applied directly to a metal surface of said container.
8. The container according to claim 2, wherein said ink changes color state at a temperature of at least about 40 degrees Celsius.
9. The container according to claim 5, wherein said ink changes color state at a temperature of at least about 40 degrees Celsius.
10. The container according to claim 6, wherein said ink changes color state at a temperature of at least about 40 degrees Celsius.
11. The container according to claim 6, wherein said ink changes color state at a temperature of at least about 40 degrees Celsius.
12. The container according to claim 2, wherein said label is applied to a metal surface of said container.
13. A self-heating container comprising:
- a. a metal container body having an enclosed volume for receiving a beverage and a bottom end with a cavity formed of metal internal walls extending upward into said enclosed volume;
- b. a solid reactant positioned within said cavity;
- c. a liquid reactant cup having a top and bottom end and a breakable barrier covering said top end to retain a liquid reactant therein;
- d. said liquid reactant cup having a an outer shoulder with a vent passage formed therethrough such that no pressure differential is created in a space above and a space below said cup; and
- e. a label attached to a surface of said container, said label comprising an irreversible ink which gives an irreversible indicia when said thermotic module has been activated.
14. The self-heating container according to claim 13, further comprising a metal end ring with a second breakable barrier attached thereto, said end ring being crimped onto a bottom of said metal container body to form a substantially moisture tight seal between an interior of said cavity and an environment outside said container.
15. The container according to claim 13, wherein said label comprises said ink applied directly to a metal surface of said container.
Type: Application
Filed: Dec 3, 2009
Publication Date: Apr 1, 2010
Inventor: Kenneth W. Kolb (Selangor)
Application Number: 12/630,599
International Classification: F24J 1/00 (20060101); B65D 85/00 (20060101);