Self-cooling food or beverage container having a heat exchange unit using liquid carbon dioxide and having a dual function valve

A self-chilling food or beverage container including an outer container and a heat exchange unit (HEU) secured internally of said outer container and having liquid carbon dioxide (CO2) therein, the HEU including a valve member which provides a restricted orifice in one position to allow the liquid CO2 to pass from the liquid state directly to the gaseous state while maintaining pressure in the HEU to keep the residual CO2 in the liquid state and in a second position to provide a substantially unrestricted flow path to permit liquid CO2 to be inserted into the HEU.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates generally to containers for holding food or beverage in which there is also included a heat exchange unit using liquid carbon dioxide and having an outer surface which contacts the food or beverage and which when activated alters the temperature of the food or beverage.

It has long been desirable to provide a simple, effective and safe device which may be housed within a container such as a food or beverage container for the purpose of altering the temperature of the food or beverage on demand.

In many instances, such as where one is in locations where ice or refrigeration are not readily available such as camping, at the beach, boating, fishing or the like it is desirable to have beverages which can be cooled before consumption. In the past it has been necessary that the individual take an ice chest or the like which contains ice and the containers for the beverages so that they can be cooled and then consumed in the manner desired. The utilization of such ice chests is cumbersome, takes up a substantial amount of space and lasts for only a very limited time after which the ice must be replaced. While in use it is also necessary that the water resulting from the melted ice be drained from the ice chest from time to time.

As a result of the foregoing, there have been numerous instances of attempts to provide a container housing a food or beverage and also housing therein a heat exchange unit which when activated would cool the food or beverage contained therein. The heat exchange units in such prior art devices housed a refrigerant material usually under pressure which when released would absorb the heat in the surrounding food or beverage thereby cooling the same prior to consumption. The refrigerants utilized in the heat exchange units of the prior art included gases under pressure such as hydroflourocarbons, ammonia, liquid nitrogen, carbon dioxide, and liquid carbon dioxide. There has also been developed a system using compacted carbon particles which adsorb carbon dioxide gas under pressure. When the HEU is exposed to the atmosphere by opening a valve, the carbon dioxide gas desorbs and cools the food or beverage in the container. Examples of such systems are shown in U.S. Pat. Nos. 7,185,511, 6,125,649 and 5,692,381. Examples of such prior art patents including carbon dioxide in its gas or liquid form is shown by U.S. Pat. Nos. 3,373,581; 4,688,395; and 4,669,273. The containers utilizing such heat exchange units as illustrated in the prior art are complex and difficult to manufacturer, thus causing great expense, rendering such prior art self-chilling beverage containers commercially unattractive. In addition, where liquid carbon dioxide was utilized, the release of the liquid carbon dioxide resulted in the liquid carbon dioxide transitioning into the solid state (dry ice) which provided only limited reduction in temperature of the food or beverage. As a result of the foregoing there exists a need for a simple, easy to assemble and efficient self cooling system for a food or beverage.

SUMMARY OF THE INVENTION

A food or beverage containing assembly comprising an outer container for receiving a food or beverage and having a top and a bottom, the bottom defining an opening therethrough, a heat exchange unit (HEU) including a metallic inner container filled with liquid carbon dioxide (CO2) and adapted to be secured to the outer container in the opening. A valve member secured to said HEU for providing a restricted orifice, when activated, to create a dis-equilibrium to permit the liquid CO2 to pass directly from the liquid state to the gaseous state but at the same time to maintain the remaining CO2 in the HEU in its liquid state. The valve member includes a valve stem that provides the dual function of charging the HEU with liquid CO2 and providing the restricted orifice.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring now more particularly toFIG. 1, there is illustrated a phase diagram for carbon dioxide. As is therein illustrated, the carbon dioxide may have a solid phase, a liquid phase or a vapor or gas phase. In accordance with the principles of the present invention it is critical that the carbon dioxide be maintained in its liquid phase and prevented from passing into a solid phase where dry ice is formed during the time that the heat exchange unit is being utilized to lower the temperature of the food or beverage within the container. As is shown, the triple point on the phase diagram is the point at which the three states of matter (gas, liquid and solid) coexist. The critical point is the point on the phase diagram at which the substance, in this instance the carbon dioxide, is indistinguishable between liquid and gaseous states. The vaporization (or condensation) curve is the curve10on the phase diagram which represents the transition between the liquid and vapor or gaseous states. As is shown, the phase diagram plots pressure typically in atmospheres on the ordinate versus temperature on the abscissa, in this case, in degrees Celsius. The lines represent the combinations of pressures and temperatures at which two phases, liquid and vapor, can exist in equilibrium. In other words, these lines define phase change points. In accordance with the principles of the present invention, the heat exchange unit is charged with carbon dioxide at a temperature and pressure such that the carbon dioxide is in its liquid state. The heat exchange unit is then sealed so that the liquid state is retained in equilibrium within the heat exchange unit until such a time as it is desired to cool the food or beverage within the container which surrounds the heat exchange unit. At that point, dis-equilibrium is created so that the liquid carbon dioxide is allowed to pass into the vapor or gaseous state but at the same time it is critical that the pressure within the heat exchange unit is maintained such that any carbon dioxide which still exists within the heat exchange unit is maintained in its liquid state. This is accomplished, as will be described in greater detail hereinbelow, by providing a path for the liquid carbon dioxide to pass from its liquid to its gaseous state and exhaust to the atmosphere by passing through a restricted orifice which has a pressure drop such that the pressure within the heat exchange unit is maintained so that the residual carbon dioxide which is contained within the heat exchange unit remains in its liquid state until such a time as all of the liquid carbon dioxide passes from its liquid state to its gaseous state and passes through the restricted orifice to the atmosphere, thereby completely exhausting the liquid carbon dioxide in the heat exchange unit.

Referring now more particularly toFIG. 2, there is illustrated partially in cross section a beverage container12having a top14and a bottom16. The bottom16has an opening therein to which is attached a heat exchange unit18. Food or beverage contained within the container12surrounds the exterior of the heat exchange unit (HEU) which is charged with liquid carbon dioxide which when released by way of a valve mechanism shown generally at20and which will be more fully described hereinafter will lower the temperature of the food or beverage to a desired level for consumption. The top14is open during the manufacturing process to permit the insertion of the HEU into the position shown inFIG. 2.

Referring now more particularly toFIG. 3, the area shown inFIG. 2circled in a dashed line and labeled as3is shown in greater detail. As is illustrated inFIG. 3, there is provided a fitting or attachment adapter22which is metal and preferably aluminum and includes threads23formed thereon to be threadably received within the upper open portion of the HEU18which has complementary threads thereon. The attachment adaptor22receives a plastic valve member24having first17and second19ends in an opening or a first bore25provided therethrough and also receives a burst disc assembly26which is also threadably received within an opening or second bore27provided within the attachment adaptor22. The attachment adaptor22has a plastic overmolded base support ring29which is applied thereto in a overmolding process in which the plastic member is formed by injection molding of polypropylene into a mold into which the attachment adaptor22has been placed. The support ring29includes an outwardly extending flange having a top surface which seats against the bottom portion16of the beverage can12and the entire assembly of the attachment adaptor22, valve24and burst disk assembly26is held in place by a base component28which will be described in greater detail below. The base component28has a snap ring member30formed by a plurality of claws that snaps over a circumferential protrusion32on the upper portion of the attachment adaptor22and thereby secures the HEU with the valve assembly20and the burst disk assembly26onto the bottom of the beverage can12. A plastic washer (not shown) may also be seated between the bottom of the can and the upper surface of the base support ring. A button component34is held in place in the base component28and, when moved downwardly, a protrusion36will engage the upper or second end19of the plastic valve member24and push it downwardly against the force of the valve spring37to provide a restricted orifice through which the liquid carbon dioxide contained within the HEU may enter the gaseous state and escape the HEU. The valve spring37is seated against a shoulder39formed by a reentrant bore41of the first bore25in the top or upper surface43of the attachment adaptor22and the lower surface of the plastic valve retainer45which is snap fitted to the top of the valve stem21. The gaseous state CO2 will pass along a restricted flow path between the exterior of the plastic valve and the opening provided in the attachment adaptor22so that the liquid CO2 which now is passing from the liquid state to the gaseous state may flow upwardly around the outer surface of the plastic valve stem21to exit the attachment adaptor22. There is, however, a gas deflector38which is positioned across the upper portion of the attachment adaptor22and operates such that when the carbon dioxide in the gaseous state flows upwardly through the opening around the valve stem21of the plastic valve24, it will be deflected radially outwardly and it will then be caused to be deflected downwardly by the base component along the outer surface40of the beverage can12as will be described more fully below.

Referring now more particularly toFIG. 4, the plastic valve24is illustrated in greater detail. As is therein shown, the plastic valve24is molded with an outwardly extending lower portion49which has a continuous sharp edge42which engages the lower surface44of the attachment adaptor22to provide a very effective seal. The valve24is molded of a polymer material which has some flexibility. As is shown inFIG. 4Athe sharp edge42of the valve24bends slightly outwardly against the surface44as shown at47to more effectively create the seal. The forces exerted on the valve24by the valve spring37and the pressure of the liquid CO2 in the HEU cause this bending. As is shown inFIG. 5to which reference is hereby made when the valve24is depressed downwardly as illustrated inFIG. 5, the section46has a first surface which is still within the bore25provided in the attachment adaptor22and functions to provide the pressure drop and the desired throttle to maintain the liquid carbon dioxide within the HEU in the boiling state so that it passes directly from the liquid to the gaseous state. This prevents the formation of dry ice and thus allows maximum cooling according to the enthalpy of vaporization. The section46of the valve24and the diameter of the bore25in the region where the section46resides are dimensioned to provide a gap between two and fourteen microns when the section46is perfectly concentric in the bore25. If the section46is not perfectly concentric then the dimensions are such that a maximum gap of between four and 28 microns is provided. The gap extends for the entire length of the section46which in accordance with the presently preferred embodiment is 0.5 mm. This gap provides the critical restricted orifice which when activated allows the liquid carbon dioxide to pass directly from the liquid state to the gaseous state but at the same time maintains the pressure in the HEU such that all of the residual carbon dioxide remains in the liquid state.

As shown inFIG. 6to which reference is hereby made, the valve24has the section46that cooperates with the bore25in the attachment adaptor22as above described. In addition thereto, the stem21of the valve24is formed with a second surface56having a smaller diameter than the first surface and is formed with a plurality of slots or flutes, some of which are shown at50,52and54. These slots operate to provide a greater flow area than is provided by the restricted orifice between the section46and the bore25in the attachment adaptor22and are used to charge the HEU with the liquid carbon dioxide. The charging is accomplished by pressing the valve24downwardly so that the section46extends below the bore25and only the second surface56is now within the bore25and at that time the carbon dioxide in liquid form under pressure from a source (not shown) is allowed to pass through the valve24through the slotted area56into the interior of the HEU in a substantially unrestricted flow path. This is maintained for a period of time, seconds, sufficient to permit the desired amount of liquid carbon dioxide to enter the HEU. At the present time, it is determined that between 85 and 95 grams of carbon dioxide in liquid form passes into the HEU. It also should be understood that the source of the carbon dioxide in liquid form is approximately 150 pounds per square inch (psi) (10.34 bar) and that the application of this pressurized source to the upper portion of the valve24will also cause it to move downwardly to allow the slotted area56to come into operation to allow the carbon dioxide to flow into the HEU.

It is better shown inFIG. 6that the valve spring37is seated within the opening41of the attachment adaptor22and also operates against the retainer45which is snap fitted onto the upper portion of the valve24and functions to retain the seal between the sharp portion42of the valve24and the lower surface44of the attachment adaptor22when the unit is in its sealed condition. The plastic valve retainer45is a molded member of polypropylene and that piece is press fitted over the end of the valve stem and it holds the spring37in place internally and is put in place once the valve is put through the bore25in the attachment adapter22. The spring37is dropped in and then the retainer45is snapped onto the top of the stem21. Referring now toFIG. 6A, the end of the valve stem21is shown at53and there is a groove55that is formed that provides a shoulder57that runs all the way around. The retainer45also has a shoulder59and when it is pressed down, it will actually expand going over the end53and then snap back into place and it then holds the retainer45on the end of the valve stem21.FIG. 6Aillustrates the manner in which the retainer is held in place on the valve stem21.

FIG. 7to which reference is hereby made shows the valve24in its closed position and is sealed. A valve top60protrudes slightly above the top62of the attachment adaptor22so that it is accessible to the button protrusion for operation as above discussed in conjunction withFIG. 3.

Referring now toFIG. 8, the valve24is shown in its gassing or charging position. As is herein shown, the filling head on the source of liquid CO2 (not shown) depresses the valve downwardly so that it is well below the upper surface62of the attachment adaptor22and in the preferred embodiment, it should be one millimeter below the top62. This then causes the section46of the valve24to be out of the bore25in the attachment adaptor22to thereby cause the slotted area56to come into operation as above discussed in conjunction withFIG. 6. This then creates the substantially unrestricted gas flow path for charging the HEU with the liquid CO2 very quickly and without generating heat.

Referring now toFIG. 9, the valve24is shown in the venting position which is accomplished by pressing the button downwardly so that the protrusion engages the top of the valve. This position opens the valve but keeps the section46inside the bore25thereby creating the restricted orifice or the throttle needed to maintain the carbon dioxide in the liquid state boiling so that it passes from the liquid to the gaseous state without the formation of solid CO2.

Referring now more particularly toFIG. 10, the function of the gas deflector is shown in greater detail. As is therein illustrated, when the liquid carbon dioxide passes into the gaseous state and flows upwardly through the space between the valve stem21and the bore25in which it is seated as above described, it will be deflected by the gas deflector38and then pass outwardly between the lower surface of the base component28and the outer surface of the center container12and is then deflected down along the outer surface of the outer container12as illustrated by the arrow64.

Referring now more particularly toFIG. 11, the base component28is illustrated in greater detail. The illustration of the base component28inFIG. 11is a perspective view of the interior surface of the base component28which creates the flow path for the liquid CO2 in a gaseous state to be deflected and passed so that it moves outwardly and downwardly around the outer surface of the beverage container12. As is shown, there are a plurality of grooves66through76extending radially outwardly through which the CO2 in the gaseous form may flow toward the outer periphery78of the base component28. The gas under this circumstance will then pass into the area shown generally at80and then will be deflected downwardly by the inner surface82of a downwardly directed outer circumferential flange83of the base component28causing it to move downwardly along the outer surface of the beverage can12as above described to enhance the cooling effect of the escaping gaseous CO2. The plurality of claws30which are used to secure the HEU assembly to the beverage can12are shown in better detail. As will be understood by those skilled in the art, when the base component28is snapped into place the claws will move outwardly over the protrusion32and then back into the groove to be secured.