SELF-COOLING CONTAINER INCLUDING LINER MEMBER, VALVE WITH AUTOMATIC SHUT-OFF AND OVERCAP PROTECTION

Abstract: A self-cooling container (10) including a heat exchange unit (24) mounted to the bottom portion of the container such that a portion of the stem valve (50) protrudes from the botom of the container for cooling a product, such as a beverage. The heat exchange unit (24) includes a chamber (28) for containing a quantity of a gas, the chamber including a wall (32) in contact with the medium to be cooled, a valve (54) for controlling the release of the gas from the chamber, a liner member (34) disposed concentric and inside the wall of the chamber for facilitating flow of the gas throughout the heat exchange unit, and a means for exhausting the gas from the chamber. The liner member includes a plurality of ribs spaced along an outer surface of the liner member to form a plurality of channels (42) when the liner member is disposed adjacent the wall.

Description: SELF-COOLING CONTAINER INCLUDING LINER MEMBER, VALVE WITH AUTOMATIC SHUT-OFF AND OVERCAP PROTECTION REFERENCE TO RELATED APPLICATION This is a continuation-in-part of U.S. Application Serial No. 08/449,131, filed May 24, 1995. BACKGROUND OF THE INVENTION Field of the Invention The present invention relates generally to temperature changing devices, and more specifically to self-cooling containers for cooling a product, such as a beverage. Description of the Prior Art It has long been desirable to provide a simple, effective and safe device which may be housed within a container, such as a beverage container, for the purpose of cooling a product, such as a beverage, on demand. Such self-cooling devices, even if effective, normally will cool the product with all of the attendant disadvantages thereof such as environmental hazard, bulkiness, expense and the like. Various types of devices have been developed to accomplish the desired self-cooling such as devices which rely on chemical endothermic and exothermic reactions, devices which require pneumatic circuits, devices using desiccant absorbing agents and water, and devices which rely on well-known electrical effects for both heating and cooling. Typical self-cooling devices known to Applicant for chilling beverages and the like are exemplified by U.S. Patent Nos. 2,460,765; 3,373,581; 3,636,726; 3,726,106; 4,584,848; 4,656,838; 4,784,678; 5,214,933; 5,285,812; 5,325,680; and 5,331,817. Self-cooling devices utilized in the prior art exemplified by the above-identified patents have generally been unsatisfactory. Some of the difficulties which have been encountered are that the devices (1) generally rely on toxic and environmentally unfriendly chemicals, (2) require very bulky pneumatic circuits and cannot economically be used in small containers such as beverage cans or foods cans, (3) are rather complex and are thus expensive to manufacture and maintain, and (4) are ineffective. What is needed therefore is a device which may be inserted in a container for self-cooling which is simple, effective and safe. SUMMARY OF THE INVENTION The preceding and other shortcomings of prior art products are addressed and overcome by the present invention which provides a container including a heat exchange unit, mounted to the bottom portion of the container such that a portion of the stem valve protrudes from the bottom of the container, for cooling a product, such as a beverage. The heat exchange unit includes a chamber for containing a quantity of a gas, the chamber including a wall in contact with the medium to be cooled, a valve for controlling the release of the gas from the chamber, a liner member disposed concentric and inside the wall of the chamber for facilitating flow of the gas throughout the heat exchange unit, and a means for exhausting the gas from the chamber. The liner member includes a plurality of ribs spaced along an outer surface of the liner member to form a plurality of channels when the liner member is disposed adjacent the wall . The liner member is formed from a material which can be wetted by liquid gas to increase the flow of the gas between the liner member and the wall. The valve additionally includes monitoring means for sensing when the heat exchange unit is tilted beyond a predetermined angle relative to the longitudinal axis of container. When the heat exchange unit is tilted beyond the predetermined angle, the valve is disabled until the heat exchange unit is subsequently repositioned within the predetermined angle. An overcap for preventing inadvertent actuation of the heat exchange unit is mounted on-the container such that it covers the entire portion of the valve stem which protrudes from the bottom portion. The overcap includes a nozzle for accelerating the gases from the chamber to a high velocity and for mixing the gases with a sufficient amount of air such that the mixture of exhaust gas and air is less than the lower flammability limit, thereby preventing any flammability upon dispensing of the product. The foregoing and additional features and advantages of this invention will become apparent from the detailed description and accompanying drawing figures that follow. In the figures and the written description, numerals indicate the various features of the invention, like numerals referring to like features throughout for both the drawing figures and the written description. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of a self-cooling beverage container including a heat exchange unit mounted therein in accordance with the present invention; FIG. 2 is a cross-sectional view of the heat exchange unit; FIG. 3(a) is a top view of the liner member of the heat exchange unit; FIG. 3(b) is a side view of the liner member as illustrated in FIG. 3(a) ; FIG. 4 is a cross-sectional view of the liner member incorporated in the heat exchange unit; FIG. 5 is an exploded view of the liner member incorporated in the heat exchange unit; FIG. 6 is a cross-sectional view of the actuator subassembly of the heat exchange unit; FIG. 7 is a side elevational view of the bottom portion of the container including an overcap mounted therein in accordance with the preferred embodiment of the present invention; FIG. 8 is a cross-sectional view of the overcap shown in FIG. 7; FIG. 9 is a detailed cross-sectional view of the overcap shown in FIG. 7 including depressions; FIG. 10 is a cross-sectional view of the overcap shown in FIG. 7 in an inactivated state; FIG. 11 is a cross-sectional view of the overcap shown in FIG. 7 in an activated state; FIG. 12 is a cross-sectional view of the actuator subassembly of the heat exchange unit mounted to the bottom portion of the container and the overcap in accordance with an alternative embodiment of the invention; and FIG. 13 is a cross-sectional view of the bottom portion of the container with the heat exchange unit mounted therein and the overcap shown in FIG. 12. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, there is shown generally a self-cooling container 10 for holding a product, such as beer, soft drinks, fruit drinks and the like, constructed in accordance with the principles of the present invention. For illustrative purposes, the present invention is illustrated and described herein using a conventional beverage container. The present invention may be implemented in both conventional and specially designed beverage containers. The present invention is not limited, however, to providing self-cooling for beverage-type containers. Rather, the present invention may be used to provide self-cooling for a variety of different applications, including but not limited to cooling beverage, food, chemical and industrial containers of various sizes and shapes, as well as conventional refrigeration systems. As is well known in the art, the conventional beverage container 10 shown in FIG. 1 includes a body portion 20, a top portion 18 and a bottom portion 14. The top portion 18 includes a lid 12 with a pull tab and the bottom portion 14 of the container 10 is substantially countersunk. As is shown in FIG. 1, the container 10, disposed in an inverted or upside down position for activation, includes a heat exchange unit (HEU) 24 mounted therein for facilitating cooling of the beverage 26 as will be explained further herein. As is therein shown, the top end 56 of the HEU 24 is mated to the bottom portion 14 of the container 10, such that a portion of the valve stem 50 of the HEU 24 projects axially beyond the bottom portion 14 of the container 10. By referring now more particularly to FIG. 2, a more detailed illustration of the HEU 24 is provided. As is therein shown, the HEU 24 includes a chamber 28, liner member 34 and actuator subassembly 44. The chamber 28 contains a gas 30, preferably a liquid gas, which is employed to cool the beverage 26 (not shown) and is contained under pressure in a compressed or liquified state. A variety of gases may be used, including, but not limited to, isobutane, propane, carbon dioxide, CFC's, HCFC's, and the like. The preferred gas 30 employed to cool the beverage 26 is HFC 152A (difluoroethane) , typically stored at a pressure of 85 p.s.i.a. at 75 degrees F. A gas mixture which may be used to cool the beverage 26 is a mixture of butane and HFC 134A (tetrafluoroethane) in a ratio of 60:40 (butane:HFC 134A) . Alternatively, the chamber 28 may contain a compressed gas 30 such as air, carbon dioxide, an air/C0 2 mixture or the like. One skilled in the art will appreciate that the mixture of the gases will vary depending on various factors, including but not limited to the degree of cooling that is desired, the nature of the gas 30, the pressure in the HEU 24, and the size and shape of the container 10 with which the HEU 24 is used. As is illustrated in FIG. 2, the chamber 28 is enclosed by a base 31, top end 56 and wall 32. The HEU 24 absorbs heat from the beverage 26 (not shown) through the wall 32 which is preferably manufactured from a heat conducting material such as aluminum. Alternatively, the HEU wall 32 may be manufactured from a plastic material, such as polycarbonate, polyethylene and polyester and the like. Referring now more specifically to FIGS. 3 (a) -5, the liner member 34 is illustrated in further detail. As will further be noted and hereinafter more fully described, the liner member 34 increases the effective heat transfer surface, thereby isolating the evaporation process and reducing the time for the gas to evaporate. As a result of this process, the time required for the heat transfer process is decreased, thereby allowing for more effective cooling of the product. As is therein shown, the liner member 34 is disposed concentric with the HEU wall 32 and surrounds the inner surface 36 of the HEU wall 32 to facilitate the flow of gas 30 throughout the HEU 24. The liner member 34 is preferably manufactured from a material, such as polypropylene, which can be wetted by the liquid gas 30 to increase the flow of gas 30 between the liner member 34 and the wall 32 of the HEU 24. Other plastics, including, but not limited to, polyester (PET) and the like may be used as well. As is shown in FIGS. 3(a) and 3(b), the liner member 34 includes a plurality of ribs 38 spaced along the outer surface 40 of the liner member 34 to form a plurality of channels 42 along the inner surface 36 of the HEU wall 32. As is shown in FIG. 4, the channels 42 extend substantially from the base 31 to the top 56 of the HEU 24. In the preferred embodiment, the ribs 38 are disposed substantially vertically, that is, substantially perpendicular to the base 30 of the HEU 24. It will be understood by those skilled in the art that the ribs 38 may be disposed in alternative configurations to provide for effective cooling of the beverage 26. For example, the ribs 38 may alternatively be spiraled to form a series of channels which are spiraled along the length of the wall 32 of the HEU 24. Typically, each rib 38 extends from the liner member 34 approximately 0.02 inch (0.51 mm) and is approximately 0.02 inch (0.51 mm) in width, and the liner member 34 is approximately 2.23 inches (56.6 mm) in height and has a length sufficient to engage the entire inside surface of the HEU wall 32. The ribs 38 are preferably spaced approximately 10 degrees apart, thus creating a liner member 34 containing approximately 36 ribs. Those skilled in the art will readily recognize that the dimensions of the ribs 38 and channels 42 will vary depending on factors, including but not limited to the dimensions of the HEU 24 in which the liner member 34 is used and the dimensions of the container 10 the HEU 24 is designed to cool. To activate the HEU 24, the container is inverted or disposed upside down as is illustrated in FIG. 1 and the HEU 24 is activated via the portion of the valve stem 50 of the HEU 24 which projects axially beyond the bottom portion 14 of the container 10. Referring to FIGS. 1 through 5, once the HEU 24 has been activated, the pressure on the liquified gas 30 in the chamber 28 decreases which causes the liquified gas 30 to flow into the bottom 31 of the chamber 28. The initial heat transfer between the beverage 26 and the liquified gas 30 occurs within the plurality of channels 42. Heat from the beverage 26 is absorbed by the liquified gas 30 through the wall 32 of the chamber 28 as the liquified gas 30 vaporizes by means of adiabatic expansion. As the temperature of the liquified gas 30 increases, the liquified gas 30 begins to boil causing bubbles which are pumped upward into the channels 42. This boiling action thus propels the liquified gas 30 upward into the channels 42 and causes virtually the entire interior surface area of the HEU wall 32 to be bathed with liquified gas, even as the liquified gas 30 level drops down to small amounts. For example, even when the level of the liquified gas 30 drops to a quarter of an inch, the liquified gas 30 will continue to be pumped up and bathe virtually the entire interior surface area of the HEU wall 32. Further exposure of the upward flowing liquified gas 30 to the heat exchange surface of the chamber 28 ' causes the liquified gas 30 to boil off. This progressive boiling and propagation of the liquified gas 30 insures that the entire interior surface of the wall 32 and the base 31 of the chamber 28 is bathed with liquified gas 30. The liner member 34 thus increases the effective heat transfer surface, thereby isolating the evaporation process and reducing the time for the gas to evaporate. As a result of this process, the time required for the heat transfer process is decreased, thereby allowing for more faster cooling of the product. Normally, when a pressurized container containing a liquefied gas is allowed to vent to atmosphere, liquefied gas will evaporate. During and after the time it self cools to a new temperature corresponding to its new vapor pressure, it absorbs heat from its surroundings. This heat causes ' the liquefied gas to evaporate. Self cooling also generates some gas. After self cooling takes place, all the gas that is generated is a result of heat being transferred through the skin of the container from its surroundings. The rate at which heat transfers into the container determines the rate at which gas is generated. Since vapor has such a poor coefficient of heat, the only surface which has effective heat transfer is the portion of the surface which is in contact with the liquefied gas. As evaporation continues, the liquefied gas level decreases in the container, thus the rate at which heat can be transferred decreases. Where the pressurized container is inside a beverage container surrounded by the beverage, there is a portion of the surface on the side of the pressurized container in contact with the beverage where little heat transfer is taking place because evaporated gas is immediately on the other side of the skin of the container. In accordance with an advantage of the present invention, by incorporating the liner into the pressurized container, essentially the entire surface area on the sides can be kept to transferring heat until nearly all the liquefied gas has been evaporated. Since evaporation can only occur where the required heat is available, evaporation on the sides will only occur in the vertical channels. The gas that is generated forms bubbles which travel up the channels to the top. When they burst, the gas collects in the top of the container and eventually exits out the valve opening to the atmosphere. As the gas bubbles travel upward, they carry liquefied gas with them, thus keeping the entire side wall bathed with liquefied gas regardless of the liquefied gas level in the container. The entire side of the wall remains effective throughout the heat transfer process. As liquefied gas evaporates, it is replaced by liquefied gas flowing into the bottom of the channels. The net result is a significant decrease in the time required to chill the beverage. In accordance with an advantage of the present invention, when a mixture of gases is desired, the present invention does not require the gases to azeotrope because of- the local agitation that occurs. In other words, as a result of the bubbling which occurs and the isolation of the evaporation process, a mixture of gases will still evaporate and maintain their initial percentages throughout the evaporation process without having to be azeotropic. As is shown more in detail in FIG. 6, the HEU 24 further includes an actuator subassembly 44 for actuating the HEU 24. The actuator subassembly 44 includes a valve 54 having a valve stem 50, which when reciprocated axially will open and close the valve 54 to allow the gas to discharge. The valve stem 50 is substantially tubular in construction and preferably fluted. The valve stem 50 extends through the top end 56 of the HEU 24 on one end and cooperates with the valve 54 on the other end. The valve stem 50 and the valve 54 are preferably manufactured from polyester (PET) , although other types of plastic, including but not limited to polypropylene, polyethylene and nylon and the like may be used. Referring now more specifically to FIG. 1, the container 10 including the HEU 24 mounted therein is illustrated in detail. As is therein shown, the top end 56 of the HEU 24 is mated to the bottom portion 14 of the container 10. In accordance with an advantage of the present invention, with the HEU 24 mounted in this configuration, the need for specially designed filling apparatus or methods is eliminated. The container 10 designed in accordance with the present invention is virtually transparent during the bottling process, thus allowing use of conventional beverage filling apparatus. The present invention, however, is not limited to mounting of the HEU 24 in the configuration illustrated in FIG. 1 and described herein. Rather, the HEU 24 may be mounted in various configurations, including but not limited to on the top portion 18 of the container 10 and along the body portion 20 of the container 10. The location where the HEU 24 is mounted will depend on various factors, including but not limited to the type of container and product to be cooled, the particular geometry of the container, and to the particulars of the filling process for the product. When the HEU 24 is inserted into the container 10 with the valve shaft 50 projecting axially through the container bottom portion 14, both the container bottom portion 14 and the HEU top portion 56 are secured together preferably by adhesive although other conventional securing means may be used as well. It will be recognized by those skilled in the art that any adhesive which is compatible with the various coatings that are internally in the container 10 and also the product, so that there is no organic or other toxic contamination insofar as the product is concerned, may be utilized to adhere the HEU 24 to the bottom 14 of the container .10. The adhesives which may be used to securely attach the HEU 24 to the container 10 include but are not limited to conventional thermal set adhesives such as an epoxy-based adhesive. This novel construction not only secures the container bottom portion 14 against unauthorized access to its inner components, but also maintains an air-tight seal for the container 10 including the HEU 24. The valve 54 includes a valve stem 50, which when reciprocated axially will open and close the valve 54 to allow the gas to discharge. For activation of the HEU 24, the container 10 is, as illustrated in FIG. 1, inverted or positioned upside down, such that the bottom portion 14 of the container 10 is exposed for activation. In accordance with the preferred embodiment of the present invention, the valve 54 includes as an integral part thereof an orientation monitor which senses if the container 10 is tipped beyond a prescribed angle relative to the longitudinal axis of the valve stem 50 and if it is, either automatically shuts off the valve 54 or only allows evaporated gas 30 to be expelled rather than liquified gas 30. The valve preferably used is the valve disclosed in U.S. Patent No. 5,348,199 incorporated herein for reference. Alternatively, the valve 54 could be of any conventional design having a valve stem 50 which when reciprocated axially will open and close the valve to 131142 PC17US96/ 07575 12 allow the gas to discharge further modified to include the orientation monitor feature described herein. For example, the valve 54 could be a conventional mechanical valve, such as a filler valve having a ball fitting in a seat and operated by spring pressure or a specially designed valve including the orientation monitor feature described herein. In a typical operation, with the valve stem 50 depressed so that the container 10 can otherwise discharge, if the container 10, which is positioned upside down for activation, is tilted too far one way or the other, the orientation monitor will cause the valve 54 to shut off, thus preventing the liquified gas 30 from spraying. In particular, when the angle the container 10 is tipped exceeds a prescribed angle relative to the longitudinal axis of the container 10, the valve 54 either automatically shuts off or only allows evaporated gas 30 to be expelled rather than liquified gas 30. In the preferred embodiment, the valve shuts off or only allows evaporated gas 30 to be expelled when the container is tipped at, or approximately at, 45 degrees. One skilled in the art will recognize that the prescribed angle may be varied to accommodate other desired operating conditions. Thus, in operation, when the container 10 is disposed upside down for activation on a substantially flat horizontal surface, the angle the container 10 is tipped is zero and the orientation monitor feature of the valve 54 is not triggered. However, when the container 10 is tipped more than 45 degrees in any direction relative to the longitudinal axis of the container 10, the orientation monitor will either automatically shut off the valve or only allow evaporated gas 30 to be expelled. So long as the degree the container 10 is tipped meets or exceeds the prescribed angle, the valve 54 remains in the closed position thus precluding all leakage of liquified gas 30. Under certain circumstances, the pressure present internally in the HEU 24 will become great enough potentially to rupture the HEU 24. For example, the HEU 24 may be particularly susceptible to internal over pressure conditions caused by external heat sources such as sunlight, heaters, radiators and the like which are normally found in the environment in which the container containing the HEU 24 is used and stored. Under these circumstances, provisions need to be made to preclude further flow of gas into the HEU 24 and to release the pressure. Thus, in accordance with another embodiment of the invention, a pressure release mechanism may be additionally incorporated into the valve 5 . The pressure release mechanism may be a conventional or specially designed pressure release mechanism integrated into the valve 54. Alternatively, a pressure relief system, such as one commonly used to release pressure in an aerosol container, may be incorporated into the container 10. In a typical operation, when the valve 54 is closed, i.e., when an elastomeric ring or gasket covers the openings in the valve stem 50, the chamber 28 is sealed and neither the liquified or evaporated gas 30 can escape from the HEU 24. When the actuator mechanism is activated, it contacts the valve stem 50 and causes the valve stem 50 to move upwardly relative to the elastomeric ring. Valve designs are also possible wherein the actuator mechanism causes lateral displacement of the stem 50 in the gasket which allows gas to flow. When the stem 50 is moved up, the openings are no longer blocked by the elastomeric ring or gasket and fluid communication is e s tablished between the gas in the chamber 28 and the axia_. passageway in the stem 50. Thus, upward movement of the stem 50 releases the pressure in the chamber 28 and allows the gas 30 to expand and evaporate and evaporative cooling occurs in the HEU 24. The HEU 24 absorbs heat from the beverage through the external wall of the HEU 24 which is preferably formed from a heat conductor like aluminum. The gas 30 flows through the passageway and is ultimately exhausted from the container 10 through the opening produced by valve stem 50. When the gas is released from the HEU 24 by depressing the bottom mounted valve 54, there is typically initially a release of a mist, this mist though harmless is startling to the user and also generates a substantial noise which is irritating to the user. To overcome these problems, the present invention provides an overcap 112 which is preferably molded from polyethylene plastic, although other durable materials may be used as well. As is shown in FIG. 7, the container 10 with the HEU mounted in the bottom portion 14 of the container has the overcap 112 attached thereto. The overcap 112 merely slips over the bottom portion 14 of the container 10 and is held in place by an adhesive which is applied to the upstanding flange. The use of the adhesive is required because upon initial activation of the valve 54 to release the gas, a pressure build up occurs and without the adhesive, the overcap 112 can be blown off the bottom portion 14 of the container 10. FIG. 8 is a cross-sectional drawing which shows the configuration of the overcap 112 upon the bottom portion 14 of the container 10. As is shown, the HEU 24 has the valve release or stem 50 extending through the bottom 14 of the container 10, which has an end thereof exposed for actuation. Actuation of the valve occurs by applying a force as shown by the arrow 122 against a button 124 which is integrally molded with the overcap 112. The button 124 moves inwardly in the direction of the arrow 122 and through the retention capabilities of the plastic stays in the activated position thus holding the stem 50 in an activated position. Being so activated, the opening in the bottom portion 20 of the container 10 into the space 128. The escaping gas then travels around the inner portion of the overcap 112 and passes upwardly along the outer surface of the container 10. As is shown FIG. 9, there is a continuous rim 130 on the bottom of the container 10. To permit the gas to pass under the continuous rim 130, there are a plurality of depressions 132, equal-angularly disposed so as to shunt the continuous rim 130 to allow the gas to pass thereunder and into the space 134. In the preferred embodiment, there are six depressions although any number may be used depending on the particular configuration desired. To allow the gas to escape from space 134, there are provided a plurality of equal angularly spaced vents 136 along the inner surface of the overcap 112 which contacts the outer surface of the container 10. The vents 136 cause the escaping gas to pass upwardly as shown by the arrow 138 along the surface of the container 10. In the preferred embodiment, there are 24 vents 136 although any number may be used depending on the particular configuration desired. In accordance with the present invention, the overcap 112 functions to eliminate misting, muffle noise and cause the escaping gas to pass along the surface of the container 10 thereby cooling the surface of the container 10. It is to be noted that the escaping gas 138 does not create any kind of harmful situation to the user and it is believed in particularly warm climate situations would provide an even somewhat welcome cooling feeling about one's hands. As indicated above, the overcap 11'2 is preferably molded in one piece from polyethylene plastic. As is shown in FIG. 10, the activating button 124 is situated approximately at the center of the bottom portion 14 of the overcap 112. The button 124 is interconnected with the body 140 of the overcap 112 by means of a flexible molded transition area 142. When the force as shown by the arrow 122 is applied to the button 124, it moves into the position as shown in FIG. 11 and retains that position once so depressed. The portions 144 of the overcap 112 are flexible to allow movement of the button 124 as shown from the position in FIG. 10 to the position in FIG. 11 but at the same time will not return to the position shown in FIG. 10 from the position shown in FIG. 11 after the force as shown by the arrow 122 is removed. In this fashion, there is a positive activation of the valve member 26 allowing the refrigerant to change phase from the liquid to the gas thereby cooling the contents of the product contained within the container 10. Referring now more specifically to FIG. 12, the bottom portion 14 of the container 10 with an overcap 74 in accordance with an alternative embodiment is illustrated in detail. As is therein shown, the bottom portion 14 of the container 10 is substantially countersunk and includes an aperture 60 defined in the center portion thereof for receiving a portion of the valve stem 50. The container bottom portion 14 is terminated at its open end by an integrally formed coupling portion 62 and the HEU top portion 56 is terminated at its open end by an integrally formed HEU coupling portion 64, which matingly fits within the container coupling portion 62. The HEU coupling portion 64 includes an inner cylinder 68 which is terminated by an inwardly extending lip 70. The inwardly extending lip 70 is preferably rolled or curled during the fabrication of the HEU 24, to provide a rounded guide for the valve stem 50. The HEU coupling portion 64 extends in an outwardly latitudinal direction (relative to the longitudinal axis of the valve stem 50) along a portion of the countersunk portion of the container bottom portion 14 until it terminates at the wall 32 of the HEU 24. Referring now more particularly to FIG. 13, an overcap 74 for facilitating actuation and preventing inadvertent actuation of the HEU 24 by carelessness, tampering and the like is illustrated in greater detail. As is therein shown, the overcap 74 is mounted on the valved end or bottom portion 14 of the container 10 such that it covers the entire portion of the valve stem 50 which protrudes from the bottom portion 14 of the container 10. A user depresses the overcap 74 to actuate the valve 54. The construction of the overcap 74 is such than when the overcap 74 is in the locked condition, the valve 54 cannot be either intentionally or accidentally actuated until the actuator on the overcap 74 is first manually placed in an operative or unlocked condition as is explained in detail below. The overcap 74 is preferably a one-piece molded overcap manufactured from a plastic such as polypropylene, although other types of plastic, including but not limited to polyethylene, nylon and the like, may be used as well. As is illustrated in FIG. 13, the overcap 74 is provided with a substantially dome-shaped body portion 75 including an outwardly extending retaining lip 76 for securing the overcap 74 to the bottom portion 14 of the container 10. The overcap 74 includes an inner support ring 78 disposed concentric with the body portion 75 such that it surrounds and encloses the portion of the valve stem 50 which protrudes from the bottom 14 of the container 10. The dimensions of the overcap 74 may be adjusted to accommodate valve stems of various heights. In a typical construction, an approximate 0.07 inch span exist between the top center portion of the valve stem 50 and the center portion of the overcap 74. With the inner support ring 78 enclosure, considerable force is required to activate the portion of the overcap 74 such that it contacts the valve stem 50, thus minimizing inadvertent actuation. To insure retention of the overcap 74 to the container 74, one of several retaining means may be employed. In the preferred embodiment of the invention, the retaining lip 76 on the overcap 74 is configured such that it may be snap or press fitted about the outer circumference of the bottom portion 14 of the container 10. Alternatively, the overcap 74 may be snap or press fitted about an inner circumference of the bottom portion 14 of the container 10. Alternatively, the overcap 74 may be configured with grooves which engage corresponding grooves formed on the container 10, thus allowing the overcap 74 to be rotatably screwed onto the appropriate portion of the container 10. In another alternative embodiment, both the retaining lip 76 and the corresponding portion of the container 10 may be secured together with adhesive. It will be recognized by those skilled in the art that any adhesive which can be utilized to adhere the overcap 74 to the container 10 and which is compatible with the various coatings that are internally in the container 10 and also the product, so that there is no organic or other toxic contamination insofar as the product is concerned. The adhesives which may be used to securely attach the HEU 24 to the container 10 include but are not limited to conventional thermal set adhesives such as an epoxy-based adhesive. Alternatively, the overcap 74 may be constructed such that it snaps onto the flange on the bottom portion 14 of the container 10. Preferably, the HEU 24 will be actuated when the overcap 74. is depressed. In a typical operation, the user must use considerable force to push the overcap 74 until it collapses and contacts the valve stem 50. It should be recognized that the present invention is not limited to a push type actuator. Rather, other types of actuators, including but not limited to actuators which require pulling or twisting for activation may be used as well. For example, a pull type actuator or a twist-type actuator may be used. The overcap 74 may additionally include tamper detection means. When the overcap 74 is actuated by pushing, a seal disposed within the overcap 74 is punctured thus providing indication to a user that the HEU 24 has been activated. It should be recognized that the present invention is not limited to the above configuration. Rather, other means to show tamper detection, including but not limited to a pull type mechanism having a seal which is punctured upon actuation and a twist type mechanism which becomes deformed after actuation, and the like. From the foregoing, it will be understood by those skilled in the art that any conventional actuating means including described herein can be utilized alone or in combination with any conventional detection means including those described herein. In accordance with the present invention, in addition to preventing inadvertent actuation of the HEU 24, the overcap 74 includes a nozzle 94 for preventing flammability of the gases. The nozzle 94 incorporated therein accelerates the exhaust gases from the chamber to a high velocity and mixes the exhaust gases with a sufficient amount of air such that the mixture of exhaust gas and air is less than the lower flammability limit, thereby preventing any flammability upon dispensing of the product . The nozzle 94 includes a plurality of orifices which are disposed on the outer circumferential end of the overcap 74 and are preferably manufactured from injection molded plastic. In the preferred embodiment of the invention, two orifices are disposed on opposing circumferential ends of the overcap 74. As is well known by those skilled in the art, certain concentrations of gas and air must co-exist in the presence of an ignition source for a flame to propagate. In particular, the lower flammability limit is the minimum concentration of an oxidizable gas in air below which propagation of flame does not occur upon contact with the ignition source. Similarly, the upper flammability limit is the maximum concentration of oxidizable gas in air, above which flame propagation does not occur. In accordance with the present invention, the orifices 96 allow enough air to be mixed in with the gas such that the concentration of gas and air is below the lower flammability limit, thus minimizing flammability hazards. Thus, in a typical operation, the nozzle 94 accelerates the escaping gases from the chamber to a velocity such that the gases will not propagate a flame and then mixes the escaping gases with a sufficient amount of air such that the mixture of exhaust gas and air is less than the lower flammability limit, thereby minimizing flammability of the gases. Furthermore, as was previously described, a variety of gases may be used in the HEU 24, including but not limited to a mixture of butane and HFC 134A. One skilled in the art will appreciate that increasing the quantity of HFC 134A in the mixture will raise the lower flammability limit of the mixture, thereby decreasing the flammability of the mixture. From the foregoing, it will be understood by those skilled in the art that the mixture herein described when used in combination with the nozzle 94 described above further minimizes flammability. As is shown above, the overcap 74 and the valve 54 are constructed such that they fittingly mate together to form one assembly. In an alternative embodiment of the invention, the overcap 74 and the valve 54 may be constructed as one integral unit which is mounted to the bottom of the container 10 as described above. It will be appreciated by persons skilled in the art that the present invention is not limited to what has been shown and described hereinabove, nor the dimensions of sizes of the physical implementation described immediately above. The scope of invention is limited solely by the claims which follow.

Claims: WHAT IS CLAIMED IS: 1. A heat exchange unit for cooling a medium comprising: a chamber for containing a quantity of a gas, said chamber including a wall in contact with said medium to be cooled; a valve for controlling the release of said gas from said chamber; a panel disposed concentric and inside said wall of said chamber for facilitating flow of said gas throughout said heat exchange unit; and a means for exhausting said gas from said chamber. 2. The heat exchange unit claimed in claim 1, wherein said valve further comprises: a valve stem which when reciprocated axially will open and close said valve to allow said gas to discharge through said stem. 3. The heat exchange unit claimed in claim 2, wherein said valve further comprises: monitoring means for sensing when said heat exchange unit is tilted beyond a predetermined angle relative to the axis of said valve stem; and disabling means responsive to said monitoring means for disabling said valve when said heat exchange unit exceeds said predetermined angle and enabling said valve when said heat exchange unit is subsequently positioned within said predetermined angle. 4. The heat exchange unit claimed in claim 3, wherein said valve either automatically shuts off or only allows evaporated gas to be expelled when disabled. 5. The heat exchange unit claimed in claim 4, further comprising: pressure release means for releasing pressure when a predetermined pressure is reached. 6. The heat exchange unit claimed in claim 5, wherein said panel further comprises : a plurality of ribs spaced along an outer surface of said panel to form a plurality of channels when said panel is disposed adjacent said wall. 7. The heat exchange unit claimed in claim 6, wherein said plurality of ribs are disposed vertically along said panel to form said plurality of channels running from the top to bottom of said heat exchange unit. 8. The heat exchange unit claimed in claim 7, wherein said panel is formed from a material which can be wetted by said gas to increase the flow of said gas between said panel and said wall. 9. The heat exchange unit claimed in claim 8, wherein said gas is liquified gas and said panel is formed from polypropylene. 10. The heat exchange unit claimed in claim 9, wherein the heat exchange unit is mounted in a pressurized container having a top, body and bottom portion, wherein the pressure in said container decreases when said container is opened. 11. The heat exchange unit claimed in claim 10, wherein said heat exchange unit is mounted to said bottom of said container. 12. The heat exchange unit claimed in claim 11, wherein said valve stem projects axially through said bottom portion of said container. 13. The heat exchange unit claimed in claim 10, wherein said heat exchange unit is mounted to said top portion of said container. 14. The heat exchange unit claimed in claim 10, wherein said heat exchange unit is mounted to said body portion of said container. 15. A self-cooling container having a top, body and bottom portion for holding a product to be cooled, comprising: a heat exchange unit for cooling a medium comprising: a chamber for containing a quantity of a gas, said chamber including a wall in contact with said product; a valve including a valve stem for controlling the release of said gas from said chamber; a panel disposed concentric and inside said wall of said chamber for facilitating flow of said gas throughout said heat exchange unit; and a means for exhausting said gas from said chamber; means for mounting said heat exchange unit to said container such that a rortion of said valve stem projects axially through conta. , er; and actuator means disposed adjacent said valve stem for activating said heat exchange unit. 16. The container claimed in claim 15, further comprising: an overcap for preventing inadvertent actuation of said heat exchange unit mounted on said container such that it covers the entire portion of said the valve stem which protrudes from said bottom portion. 17. The container claimed in claim 16, wherein said overcap further comprises: a nozzle for accelerating said gases from said chamber to a high velocity and for mixing said gases with a sufficient amount of air such that the mixture of exhaust gas and air is less than the lower flammability limit, thereby preventing any flammability upon dispensing of the product. 18. The container claimed in claim 17, wherein said nozzle further comprises: a plurality of orifices which are disposed on the outer circumferential end of said overcap and are preferably manufactured from injection molded plastic. 19. The heat exchange unit claimed in claim 18, wherein said valve -stem which when reciprocated axially will open and close said valve to allow said gas to discharge through said stem. 20. The heat exchange unit claimed in claim 19, wherein said valve further comprises: monitoring means for sensing when said heat exchange unit is tilted beyond a predetermined angle relative to the axis of said valve stem; and means responsive to said monitoring means for disabling said valve when said heat exchange unit exceeds said predetermined angle and enabling said valve when said heat exchange unit is subsequently positioned within said predetermined angle. 21. The heat exchange unit claimed in claim 20, wherein said valve either automatically shuts off or only allows evaporated gas to be expelled when disabled. 22. The heat exchange unit claimed in claim 21, further comprising: pressure release means for releasing pressure when a predetermined pressure is reached. 23. The heat exchange unit claimed in claim 22, wherein said heat exchange unit is mounted to said bottom of said container. 24. The heat exchange unit claimed in claim 23, wherein said valve stem projects axially through said bottom portion of said container. 25. The heat exchange unit claimed in claim 24, wherein said heat exchange unit is mounted to said top portion of said container. 26. The heat exchange unit claimed in claim 25, wherein said heat exchange unit is mounted to said body portion of said container. 27. The container claimed in claim 26, wherein said panel further comprises: a plurality of ribs spaced along an outer surface of said panel- to form a plurality of channels when said panel is disposed adjacent said wall. 28. The heat exchange unit claimed in claim 27, wherein said plurality of ribs are disposed vertically along said panel to form said plurality of channels running from the top to bottom of said heat exchange unit. 29. The heat exchange unit claimed in claim 28, wherein said panel is formed from a material which can be wetted by said gas to increase the flow of said gas between said panel and said wall. 30. The heat exchange unit claimed in claim 29, wherein said gas is liquified gas and said panel is formed from polypropylene.

Inventors: JOSLIN WILLIAM DANIEL JR, JOSLIN, WILLIAM , DANIEL, JR.
Applicants: JOSEPH CO, THE JOSEPH COMPANY
Application year: 1996
Main classification: F25D3
IPC codes: F25D3