WO2007147108A2 - Portable heating device ventilation - Google Patents

Abstract

A heating device includes a sealed container and a sleeve inside the container. The sleeve defines an interior space adapted to be in fluid communication with reactants from a user-initiated exothermic chemical reaction. The sleeve has surfaces that respectively define a lower ventilation port between the interior space and a lower ventilation passage and an upper ventilation port between the interior space and an upper ventilation passage. The sleeve and the container have surfaces that cooperatively define the upper ventilation passage and the lower ventilation passage. The upper and lower ventilation passages extend at least partially around a perimeter of the sleeve. The container has a surface that defines an exit port that facilitates fluid communication from the upper and lower ventilation passages to outside.

Description

PORTABLE HEATING DEVICE VENTILATION

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims the benefits of and priority to U.S. Provisional Patent Application Ser. No. 60/814,389, filed on June 16, 2006, the disclosure of which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

This disclosure relates to a heating device and, more particularly, to a portable heating device that uses an exothermic chemical reaction to produce heat.

BACKGROUND

Self-heating devices that use exothermic chemical reactions in a water solution to produce a heating effect are known. Single-use chemical heaters for heating objects, for example food and beverage items, and body parts are well known. One type of heater utilizes the exothermic reaction of a metal oxide, typically calcium oxide, and water to generate heat. U.S. Patent No. 5,035,230 ("the '230 patent"), incorporated by reference herein in its entirety, discloses heaters utilizing the oxidation of primary or secondary alcohols by appropriate oxidizers to provide exothermic chemical reactions.

PCT Publication No. WO 2005/108878 ("the '878 publication"), published November 17, 2005, incorporated by reference, discloses a method of providing a releasable reaction suppressant composition and, in response to a selected temperature occurring at a product compartment, automatically releasing the suppressant composition into the reaction chamber, thereby suppressing the exothermic reaction.

U.S. Patent No. 6,640,801 ("the' 801 patent"), also incorporated by reference, discloses a flexible disposable heating device conformable to a shape defined by its surroundings. The heating device includes a first zone containing a fuel, a second zone containing an oxidizer and a collapsed third zone capable of serving as an expansion chamber. A first frangible separator is disposed between the first zone and the second zone, the first frangible separator being manually operable to provide communication there between the zones, thereby defining a reaction chamber comprising at least one of the first and second chambers. A second frangible separator is provided that is responsive to an exothermic chemical reaction within the reaction chamber. The second frangible separator is operable to provide vapor communication between the reaction chamber and the third zone.

Communication between the first zone and the second zone allows mixing of the fuel and the oxidizing agent to initiate an exothermic chemical reaction capable of generating a vapor and an environmental parameter associated with the exothermic chemical reaction, generally temperature or pressure, operates the second frangible separator, permitting the vapor to flow into the third zone, reducing pressure in the reaction chamber.

In such heaters, heat is typically transferred to the product to be heated by steam from the exothermic reaction condensing on a surface of the product container.

SUMMARY OF THE INVENTION

In one aspect, a heating device includes a sealed container and a sleeve coupled to the container. The sleeve defines an interior space adapted to be in fluid communication with reactants from a user-initiated exothermic chemical reaction. The sleeve has surfaces that respectively define a lower ventilation port between the interior space and a lower ventilation passage, and an upper ventilation port between the interior space and an upper ventilation passage. The sleeve and the container have surfaces that cooperatively define the upper ventilation passage and the lower ventilation passage. The upper and lower ventilation passages extend at least partially around a perimeter of the sleeve. The container has a surface that defines an exit port facilitating fluid communication between the upper and lower ventilation passages and outside. hi some implementations, the lower ventilation port is peripherally displaced from alignment with the upper ventilation port. In some implementations, the lower ventilation port is at a peripherally opposite position from alignment with the upper ventilation port.

Typically, the upper ventilation port is so positioned that, when the heating device is operated in an upright position, the upper ventilation port is above a liquid line associated with the reactants. Additionally, the lower ventilation port typically is positioned so that, when the heating device is operated upside down, the lower ventilation port is above a liquid line associated with the reactants. Moreover, the upper and lower ventilation ports typically are positioned so that, when the heating device is operated on its side, at least one of the upper or lower ventilation ports is above a liquid line associated with the reactants.

In certain embodiments the sleeve and the container have surfaces that cooperatively define a plenum between and in fluid communication with the upper ventilation passage and the lower ventilation passage. In those instances, the exit port enables fluid communication directly from the plenum to outside. hi another aspect, a heating device includes a sealed container and a sleeve coupled to the container. The sleeve defines an interior space adapted to be in fluid communication with reactants from a user-initiated exothermic chemical reaction. The sleeve has surfaces that define upper ventilation ports between the interior space and one or more upper ventilation passages. The upper ventilation ports are peripherally displaced from one another around the sleeve. The sleeve and the container have surfaces that cooperatively define the one or more upper ventilation passages, each of which extends at least partially around a periphery of the sleeve. The container has a surface that defines an exit port adapted to facilitate fluid communication between the one or more ventilation passages and outside. According to yet another aspect, a vent system for a reaction chamber adapted to contain an exothermic chemical reaction is disclosed. The vent system includes a sleeve defining the reaction chamber. Upper reaction chamber openings are formed in the sleeve and peripherally displaced from one another around the sleeve. A vent passage is coupled to each upper reaction chamber opening. The vent passages extend peripherally about the sleeve. An external opening is formed in each vent passage. Each external opening is peripherally displaced from an associated one of the upper reaction chamber openings.

In still another aspect, a method of venting excess steam from an exothermic chemical reaction occurring in a portable heating device is disclosed. The method includes providing a heating device that has a sealed container and a sleeve coupled to the container. The sleeve defines an interior space adapted to be in fluid communication with reactants from a user-initiated exothermic chemical reaction. The sleeve has surfaces that respectively define a lower ventilation port between the interior space and a lower ventilation passage, and an upper ventilation port between the interior space and an upper ventilation passage. The sleeve and the container have surfaces that cooperatively define the upper ventilation passage and the lower ventilation passage. The upper and lower ventilation passages extend at least partially around a perimeter of the sleeve. The container has a surface that defines an exit port facilitating fluid communication from the upper and lower ventilation passages and outside. The method includes initiating the exothermic chemical reaction and enabling excess steam from the exothermic chemical reaction to exit the heating device via at least one of the upper or lower ventilation ports, an associated one or more of the upper or lower ventilation passages and the exit port.

According to another aspect, a heating device includes a reaction chamber housing adapted to be in fluid communication with reactants from a user-initiated exothermic chemical reaction. The reaction chamber housing has surfaces that respectively define a lower ventilation port between the chamber and a lower ventilation passage, and an upper ventilation port between the chamber and an upper ventilation passage. Tubes are coupled to the reaction chamber housing and have surfaces that define the upper ventilation passage and the lower ventilation passage. The upper and lower ventilation passages extend at least partially around a perimeter of the sleeve. The tubes have respective surfaces that define exit ports. The exit ports facilitate fluid communication between the upper and lower ventilation passages and outside. In some implementations, the tubes are inside the housing. In other implementations, the tubes are outside the housing. This application includes numerous references to relative terms, such as upper, lower, top, bottom, etc. Unless otherwise indicated, those terms should be understood as identifying the relative positions of elements in the heating devices disclosed herein when the heating device is in an upright position. Moreover, as a variety of specific configurations of the features and techniques described herein are possible, the terminology used herein should be construed broadly. For example, the terms "container" and "sleeve" should be construed so as to include a variety of structures of varying shapes, dimensions, and configurations.

In certain implementations, one or more of the following advantages may be present. In general, overheating of portable heaters that use exothermic chemical reactions to create heat maybe minimized.

More particularly, if food or other product or heat sink intended to be heated is absent from a container, the techniques and features disclosed herein may help to safely ventilate the reaction chamber and release excess steam in a safe manner. The steam is released, while the liquid reactants are contained. Certain implementations enable that functionality regardless of whether the heating device is upright, on its side or even upside down, hi some implementations, the techniques and features disclosed herein can help prevent the build-up of potentially dangerous high pressures inside a reaction chamber of a chemical heater. The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view of an implementation of a portable, user- activatable heating device.

FIGS. 2 A and 2B are cutaway views of the heating device of FIG. 1 in an assembled state. FIG. 3 is an exploded view of another implementation of a portable, user- activatable heating device.

FIG. 4 is a partial cutaway view of the heating device of FIG. 3 in an assembled state. FIG. 5 is a perspective and partial cutaway view of another implementation of a heating device.

FIG. 6 is a cutaway plan view of the heating device of FIG. 5.

FIG. 7 is a perspective and partial cutaway view of yet another implementation of a heating device. FIG. 8 is a cutaway plan view of the heating device of FIG. 7.

Like reference numerals refer to like elements.

DETAILED DESCRIPTION

FIG. 1 is an exploded view of an implementation of a portable, user- activatable heating device 100 that is adapted to heat a product, such as coffee, soup or the like, by using heat from an exothermic chemical reaction inside the heating device 100.

The illustrated heating device 100 includes an external container 102, a mixing chamber 104, a frangible seal 106, a sleeve 108, a sealing element 110, a product container 112 and a suppressant ring 114. To initiate heating, the frangible seal 106 is ruptured, which allows chemical reactants initially contained above the frangible seal to drop into other chemical reactants initially contained below the frangible seal. That mixing of chemical reactants initiates the exothermic chemical reaction. The exothermic chemical reaction produces steam that contacts an outer surface of the product container 112. Typically, the steam condenses on the outer surface of the product container 112 as latent heat of vaporization is transferred from the steam to the product therein.

In certain situations, the amount of product inside the product container may be insufficient to utilize all the heat generated by the exothermic chemical reaction and carried by the steam. In that case, not all of the steam is condensed on the product container's 112 outer surface. The illustrated heating device 100 is adapted so that, in those instances, the steam that is not condensed on the product container's 112 outer surface is released to atmosphere without rupturing the heating device 100 and without releasing the liquid reactants to atmosphere.

The external container 102 has a body portion 116 and a cover portion 118. The body portion 116 is substantially cylindrical, with an open top and a closed bottom. Several exit ports 120 are formed in the body portion 116, each of which enables fluid communication between the inside of the body portion 116 and atmosphere. All of the exit ports 120 are at approximately the same height above the bottom of the body portion 116. More particularly, all of the exit ports 120 are about midway up the height of the body portion 116.

External threads 122 are exposed near the open top of the body portion 116. Below the external threads 122 is a ring of teeth 124. The teeth 124 are adapted to interact with corresponding features (not visible in FIG. 1) on an inner surface of the cover portion to prevent a user from unscrewing the cover portion 118 from the body portion 116.

The body portion 116 also includes an upper row and a lower row of discrete ramped surfaces 126 on its substantially cylindrical inner surface. The upper row of ramped surfaces 126, which is partially visible in FIG. 1, is above the exit ports 120. The lower row, which is not visible in FIG. 1, is below the exit ports 120.

Each ramped surface 126 ramps, in a downward direction, away from the inner surface of the body portion 104 so that the highest points of each ramp, relative to the inner surface of the body portion 116, is at the bottom of the ramp. The ramped surfaces 126 only extend a short distance in an up and down direction; typically, less than an inch. There are spaces between adjacent ramped surfaces 126. When the heating device 100 is activated, the ramped surfaces come into contact with seals 142, 144, causing those seals to deform, thereby compromising their sealing capabilities.

The cover portion of the external container 102 also is substantially cylindrical. The bottom of the cover portion 118 is open and is adapted to receive the threaded upper part of the body portion 116. The cover portion 118 has internal threads, which are not visible in FIG. 1, that mate with the external threads 122 on the body portion 116 of the external container 102.

The top surface 128 of the cover portion 118 has a hole 130 in it. The hole 130 is provided so that the product inside (e.g., coffee) can be accessed. The top surface 128 is recessed relative to the upper edges of the cover portion 118. That arrangement advantageously minimizes spillage of product when, for example, it is being drank.

Ribs 125 are exposed at an outer surface of the cover portion 118 and are distributed around its periphery. The ribs 125 enhance the cover portion's 118 structural rigidity and make it easier for a user to turn the cover portion 118 relative to the body portion 116.

When assembled, the mixing chamber 104 sits in the bottom of the external container 102. The mixing chamber 104 is substantially cylindrical, has a closed bottom and an open top. Ribs 132 are exposed at an outer surface of the mixing chamber 104 and are distributed around its periphery. The ribs 132 enhance the mixing chamber's structural rigidity and interact with the inner surface of body portion 116 to keep the mixing chamber 104 in place. In some implementations, the inner surface of the body portion 116 includes structural features, such as grooves, that complement the ribs 132 on the mixing chamber 104 in such a manner that facilitates keeping the mixing chamber 104 in place. The ribs also helps support the frame 134 of the frangible seal 136.

In assembly, but prior to activation of the heating device 100, the mixing chamber 104 contains at least one of the reactants required to produce the exothermic chemical reaction. Usually, that reactant(s) is in a high surface area solid form. Examples of high surface area solids include powders, aluminum wool, and foil.

The frangible seal 106 includes a frame 134 and a frangible portion 136. The frame 134 is substantially annular and typically is made of a substantially non- frangible material, such as a metal or the like. When assembled, but prior to activation of the heating device 100, the frangible seal 136 sits inside the external container 102, with its frame 134 atop the upper edge of the mixing chamber 104. The frame 134 may be at least partially supported by the ribs 132 on the mixing chamber 104.

The frangible portion 136 of the frangible seal 106 is made of a frangible material, such as glass, plastic or the like. Prior to activation of the heating device 100, the frangible portion 136 is intact and extends across the central portion of the frame 134. The illustrated frangible portion 136 is scored with lines that extend radially outward from its center. Providing score lines in a frangible portion 136 of a frangible seal 106 can help ensure that when the frangible portion 136 ruptures, it does so completely, which is desirable to facilitate thorough mixing of reactants. In some implementations, the frangible seal 106 has a sufficiently large diameter that, when it is positioned inside the external container, its frame 134 contacts the inner surface of the external container 102. In some instances, the frame 134 can seal against that inner surface. Typically, the frangible seal 106 seals against the upper edge of the mixing chamber 104. In assembly, but prior to activation of the heating device 100, the space above the frangible seal 106 contains at least one of the reactants required to produce the exothermic chemical reaction. Usually, that reactant(s) is in a liquid form. Typically, the reactant(s) that is initially stored above the frangible seal 106 is adapted to exothermically react with the reactant(s) that is initially stored in the mixing chamber 104. Accordingly, when the frangible seal 106 is ruptured, the reactant(s) that is initially stored above the frangible seal 106 drops into the reactant that is initially stored in the mixing chamber 104, thereby initiating the exothermic chemical reaction.

The sleeve 108 is substantially cylindrical and hollow. It has an open top and an open bottom. The sleeve 108 includes castellated top 138 and bottom 140 surfaces, an outer surface with annular upper 142 and lower 144 seals, upper 145 and lower 146 threaded sections, and a smooth section 148 between the upper 145 and lower 146 threaded sections.

Each of the upper 145 and lower 146 threaded sections includes four threads 154. Each thread 154 extends at least partially around the perimeter of the sleeve 108 and from the smooth section 148 to near either the upper 142 or lower 144 seal. In some implementations, each thread 154 extends approximately 180 degrees from end to end. In some implementations, the lower ends of adjacent threads 154 are displaced from one another by about 90 degrees and the upper ends of adjacent threads 154 also are displaced from one another by about 90 degrees. The threads are dimensioned such that when the sleeve is inside the external container 102, the outer edges of the threads are in contact with the inner surface of the external container 102. In some implementations, the threads are substantially rigid. In some implementations, the threads are substantially flexible.

Typically, the annular upper and lower seals 142, 144 are made from a deformable material. Those seals 142, 144 are secured to the sleeve 108 so that they can move with the sleeve axially through the external container 102. The annular upper and lower seals 142, 144 are dimensioned to seal against smooth (i.e., ramp- free) sections of the inner surface of the external container. Furthermore, those seals 142, 144 are dimensioned to accommodate a sufficient amount of deformation upon contacting the ramped surfaces 126 in the container 102 that their sealing ability is compromised.

The sealing element 110 is annular and includes an upper portion 150 connected to a lower portion 152. The upper portion 150 has a smaller diameter than the lower portion 152. The sealing element 110 typically is a flexible material, such as rubber, plastic or the like.

In assembly, the upper portion 150 of the sealing element 110 is adhered to the product container 112 and the lower portion 152 of the sealing element 110 is adhered to the sleeve 108. The outer edge of the lower portion 152 of the sealing element 110 is dimensioned so as to contact and substantially seal against the inner surface of the external container 102. Such an arrangement helps to prevent reactants and other reaction fluids from escaping the heating device 100 around the upper edge of the product container 112 either during shipment, use or otherwise.

The product container 112 has an open top, a closed bottom and three annular sections: an upper section 156, an intermediate section 158 and a lower section 160. Of those, the upper section 156 has the largest diameter and the lower section has the smallest diameter. The upper section 156 is adapted to be adhered to the sealing element 110. The intermediate 158 and lower 160 sections define an interior space adapted to contain the product. Typically, the product container 112 is made of a metallic or otherwise thermally conductive material.

The suppressant ring 114 is annular with an open top and an open bottom. It includes a suppressant composition dispersed in a fusible component. In some implementations, the composition of the suppressant ring 114 is similar to the compositions disclosed, for example, in copending U.S. Patent Application Nos. 11/568,683 and 60/864,723, which are hereby incorporated by reference in their entireties. In assembly, the suppressant ring 114 fits around and is adhered to the lower section 160 of the product container 112 in such a manner that, in response to the product container 112 reaching a predetermined temperature, the suppressant ring is automatically released from the lower section of the product container 112 so it can fall into and suppress the reaction occurring below it. FIGS. 2 A and 2B are cutaway views of the heating device 100 of FIG. 1 in an assembled state. In FIG. 2A, the heating device 100 is in an unactivated state (i.e., an exothermic chemical reaction has not yet been initiated). In FIG. 2B, the heating device is in an activated state (i.e., an exothermic chemical reaction has been initiated). When assembled, the product container 112 is nested inside the sleeve 108.

The suppression ring 114 is adhered to the lower section 160 of the product container 112. The sealing element 110 is fitted around the product container 112 and adhered thereto. The sealing element 110 also is adhered to the sleeve 108. The sleeve 108 is inside the external container 102 in such a manner that the outer edges of the upper 145 and lower 146 threaded sections are very close to or in contact with the inner surface of the external container 102. The mixing chamber 104 is in place at the bottom of the external container 102.

In FIG. 2A, before the exothermic chemical reaction is initiated, the frangible seal 106 is above the mixing chamber 104 and below the product container 112. The mixing chamber 104 contains at least one of the reactants required for the exothermic chemical reaction. The space 202 above the frangible seal 106 contains at least one other reactant required for the exothermic chemical reaction, typically in a liquid form.

By comparing FIGS. 2A and 2B, it can be seen that, to initiate the exothermic chemical reaction, the product container 112, the sealing element 110 and the sleeve 108 move together from the raised position shown in FIG. 2A (unactivated) to the lowered position shown in FIG. 2B (activated). When those elements are moved in that manner, the bottom surface of the product container 112 breaks through and ruptures the frangible portion of the frangible seal 106. When the frangible portion is ruptured, the liquid reactants that were initially stored in the space 202 above the frangible seal 106 drop into the reactants that were initially contained in the mixing chamber 104 below the frangible seal 106. An exothermic chemical reaction ensues as the reactants mix with each other and steam is generated.

Additionally, as the product container 112, sealing element 110 and sleeve 108 move from the raised position shown in FIG. 2A (unactivated) to the lowered position shown in FIG. 2B (activated), the upper 142 and lower 144 seals on the sleeve 108 move from an upper position where they are in contact with the cylindrical inner surface of the external container 102 and sealing against that surface (FIG. 2A) to a lower position where they are in contact with respective upper 126 and lower 210 sets of ramped surfaces. As discussed above, contact with the ramped surfaces causes the upper 142 and lower 144 seals to deform in a manner that compromises their sealing capabilities, thereby creating a flow path in an axial direction past those seals 142, 144.

Referring now to FIG. 2B, when the exothermic chemical reaction is ongoing and steam is being generated, an interior space 204 within the sleeve 108 is in fluid communication with the reactants and with the steam. The castellated bottom surface 140 of the sleeve 108, in conjunction with the upper surface of the frangible seal frame 134, defines lower ventilation ports 206 that enable fluid communication between the interior space 204 and a space 214 between the sleeve 108 and the external container 102 below the lower threaded section 146 of the sleeve 108. Similarly, the castellated top surface of the sleeve 108, in conjunction with the sealing element 110 defines upper ventilation ports that enable fluid communication between the interior space 204 and a space 216 between the sleeve 108 and the external container 102 above the upper threaded section 145 of the sleeve 108.

The upper threaded section 145 of the sleeve 108, in conjunction with the inner surface of the container 102, defines upper ventilation passages 212 that extend at least partially around a perimeter of the sleeve 108. Similarly, the lower threaded section 145 of the sleeve 108, in conjunction with the inner surface of the container 102, defines lower ventilation passages 220 that extend at least partially around a perimeter of the sleeve 108. A plenum 218 is between the upper ventilation passages 212 and lower ventilation passages 220 and is defined by the smooth section 148 of the sleeve 108 between the upper 145 and lower 146 threaded sections and by the inner surface of the external container 102. The upper ventilation passages 212 extend between space 216 and the plenum 218. Similarly, the lower ventilation passages 220 extend between space 214 and plenum 218. The exit ports 120 enable fluid communication between the plenum 218 and outside (i.e., atmosphere). To move the product container 112, sealing element 110 and sleeve 108 from the raised position shown in FIG. 2A (unactivated) to the lowered position shown in FIG. 2B (activated), a user can rotate the cover portion 118 of the external container 102 clockwise looking downward relative to the body portion 116 of the external container 102. That action causes the cover portion 118 to move axially downward relative to the body portion 116 and to push the product container 112, sealing element 110 and sleeve with it.

During typical operations, if there is product inside the product compartment, heat from the exothermic chemical reaction is absorbed by the product, hi that situation, most of the steam from the reaction condenses on the outer surface of the product container 112. If there is insufficient product in the product container 142 to sufficiently condense the steam, the excess steam can be vented to atmosphere without allowing the liquid reaction components to escape from the heating device 100.

In a typical implementation, the upper ventilation ports 216 are positioned at a height such that, when the heating device 100 is operated in an upright position, the upper ventilation ports 216 are above a liquid line associated with the reactants. Accordingly, if excess steam is generated by the exothermic chemical reaction, that steam can escape by passing through the upper ventilation ports 216, the upper ventilation passages 212, the plenum 218 and out through the exit ports 120. That can happen even if the lower ventilation ports 206 are beneath the liquid line and are, therefore, blocked. Moreover, in that way, excess steam is released without also allowing the liquid reactants to escape.

Additionally, in a typical implementation, the lower ventilation ports 206 are positioned at a height such that, when the heating device 100 is operating and is upside down, the lower ventilation ports 206 are above the liquid line associated with the reactants. Accordingly, if excess steam is generated by the exothermic chemical reaction, that steam can escape through the lower ventilation ports 206, the lower ventilation passages 220, the plenum 218 and out through the exit ports 120. That can happen even if the upper ventilation ports 216 are beneath the liquid line and are, therefore, blocked. Moreover, in that way, excess steam is released without also allowing the liquid reactants to escape.

Since there are upper 216 and lower 206 ventilation ports are distributed around substantially the entire periphery of the sleeve 108, if the heating device 100 is operational while laying on its side, there should always be one or more ventilation ports (upper and/or lower) that are above the liquid line associated with the reactants. Accordingly, if excess steam is generated by the exothermic chemical reaction, that excess steam can escape, even if some of the ventilation ports are beneath the liquid line and, therefore, blocked. Moreover, in that way, steam is released without also allowing the liquid reactants to escape.

FIG. 3 is an exploded view of another implementation of a heating device 300. The illustrated heating device 300 is similar to the heating device 100 of FIG.

1 except the sleeve 308 has a different design and, operationally, only the product container 102 and the sealing element 110 move axially relative to the body portion 116 of the external container 102. The sleeve 308 remains stationary relative to the body portion 116 of the external container 102. The illustrated sleeve 308 is hollow and substantially cylindrical. The sleeve

308 has surfaces that define ventilation ports that extend from inside the sleeve 308, radially through the sleeve 308 to outside the sleeve 308, Although only two are visible in FIG. 3, that implementation includes two upper ventilation ports 316 and two lower ventilation ports. The non- visible upper and lower ventilation ports are at approximately radially opposite spots as the visible upper 316 and lower 306 ventilation ports, respectively.

A channel is formed in the outer surface of the sleeve 308. The channel 380 defines axial extensions 382, each of which is associated with one of the upper 316 or lower 306 ventilation ports. Each axial extension 382 is directly connected to a peripheral extension 384 that extends at least partially around a periphery of the sleeve 308. Each peripheral extension connects to a plenum connector 386, which connects to a plenum surface 388.

FIG. 4 is a partial cutaway view of the heating device 300 of FIG. 3, assembled. In assembly, the sleeve 308 sits inside the external container 102 so that the outer surface of the sleeve 308 is in close contact with the corresponding inner surface of the external container 102. When so assembled, the axial extensions 382 associated with the upper ventilation ports 316, the associated peripheral extensions 384 and the associated plenum connectors 386, in conjunction with the inner surface of the external container's body portion 116, define upper ventilation passages 412. Each upper ventilation passage 412 extends approximately 180 degrees around a periphery of the sleeve 308. Each upper ventilation passage 412 enables fluid communication between its associated ventilation port 316 and the plenum 418.

Similarly, the axial extensions 382 associated with the lower ventilation ports 306, the associated peripheral extensions 384 and the associated plenum connectors 386, in conjunction with the inner surface of the external container's body portion 116, define lower ventilation passages 420. Each lower ventilation passage 420 extends approximately 180 degrees around a periphery of the sleeve 308. Each lower ventilation passage 420 enables fluid communication between its associated lower ventilation port 306 and the plenum 418.

The exit ports 120 in the external container's body portion are aligned with the plenum 418 so that the exit portions enable fluid communication between the plenum 418 and outside {i.e., atmosphere). In a typical implementation, the upper ventilation ports 316 are positioned at a height such that, when the heating device 300 is operated in an upright position, the upper ventilation ports 316 are above a liquid line associated with the reactants. Accordingly, if excess steam is generated by the exothermic chemical reaction, that steam can escape by passing through the upper ventilation ports 316, the upper ventilation passages 312, the plenum 418 and out through the exit ports 120. That can happen even if the lower ventilation ports 306 are beneath the liquid line and are, therefore, blocked. Moreover, in that way, excess steam is released without also allowing the liquid reactants to escape. Additionally, in a typical implementation, the lower ventilation ports 306 are positioned at a height such that, when the heating device 300 is operating and is upside down, the lower ventilation ports 306 are above the liquid line associated with the reactants. Accordingly, if excess steam is generated by the exothermic chemical reaction, that steam can escape through the lower ventilation ports 306, the lower ventilation passages 420, the plenum 418 and out through the exit ports 120. That can happen even if the upper ventilation ports 316 are beneath the liquid line and are, therefore, blocked. Moreover, in that way, excess steam is released without also allowing the liquid reactants to escape.

Since there are upper ventilation ports 316 situated approximately diametrically opposite one another and since there are lower ventilation ports 306 similarly situated relative to one another, but displaced from alignment with the upper ventilation ports by about 90 degrees, if the heating device 300 is operational while laying on its side, there should always be one or more ventilation ports (upper and/or lower) that are above the liquid line associated with the reactants. Accordingly, if excess steam is generated by the exothermic chemical reaction, that excess steam can escape, even if some of the ventilation ports are beneath the liquid line and, therefore, blocked. Moreover, in that way, steam is released without also allowing the liquid reactants to escape.

FIGS. 5 and 6 depict an embodiment of a heating device 500 that is adapted to produce heat through an exothermic chemical reaction. The heating device 500 includes a container 502 and a sleeve 508 inside the container 502. In some implementations, a product compartment (not shown) containing a product to be heated is nested within the sleeve 508 and thermally coupled to the reaction that takes place at an interior space inside the sleeve. The illustrated sleeve 508 is cup-shaped and has a closed bottom. The sleeve

508 has surfaces that define upper ventilation ports 526 that enable fluid communication between the interior space and associated upper ventilation passages 514. The illustrated container 502 is annular and adapted to fit around the sleeve 508 at such height that is equal to the height of the upper ventilation ports 526 formed in the sleeve 508.

In some implementations, a cross-section of the container 502 (taken, for example, at A-A in FIG. 5) includes four walls. In those instances, the container 502 includes openings through its inner wall that align with the upper ventilation ports 526 formed in the sleeve 508. In those instances, the inner wall of the container 502 is in contact with the outer surface of the sleeve 508 and the container defines the upper ventilation passages independently (i.e., not in cooperation with the sleeve 508).

In some implementations, a cross-section of the container 502 (taken for example, at A-A in FIG. 5) includes three walls. In those instances, the container 502 defines the upper ventilation passages in cooperation with the outer surface of the sleeve 508.

The upper ventilation ports 526 are peripherally displaced from one another around the sleeve 508. The sleeve 508 and the container 502 also have surfaces that cooperatively define the upper ventilation passages 514, each of which extends at least partially around a periphery of the sleeve 508. The container 502 has surfaces that define exit ports 520 that facilitate fluid communication between the associated upper ventilation passages 514 and outside.

The illustrated heating device 500 is adapted to accommodate an exothermic chemical reaction to produce heat therein. In some implementations, the reaction involves the oxidation of primary or secondary alcohols by appropriate oxidizers to produce heat. Compounds of manganese and chromium are commonly used oxidizing agents. Glycerol and ethylene glycol are commonly used primary alcohol fuels. Alkali metal permanganates also are useful as oxidizing agents, generally in aqueous reactions. Water can be used to dilute the fuel component and to lower the chemical reaction rate by reducing fuel-to-oxidizer contact. The reaction can involve embedded solid oxidizer particles, such as particles of potassium permanganate, in a dissolvable binder, for example sodium silicate, to further reduce the fuel-to-oxidizer contact for improved control over the rate of reaction.

The reaction typically results in steam being produced in the interior space of the sleeve 508. That steam is used to heat the product (for example, food or drink) that is in thermal contact with that heat. If, for example, a product container (not shown) is nested inside the sleeve 508, heat from the steam passes through the product container and heats the product therein. With the heat transfer, steam condenses on an outer surface of the product container.

Li FIG. 5, the container 502 is shown in an upright position (i.e., it is not on its side or upside down). With the container 502 oriented in that way, excess steam can be vented to atmosphere through either or both of the upper ventilation ports 526, their associated upper ventilation passages 514 and the associated exit ports 520. Moreover, if the heating device 500 is oriented on its side, since the upper reaction chamber ventilation ports 526 are provided at approximately diametrically opposite points on the sleeve 508, one will likely always be above a liquid line associated with the reactants and steam will be allowed to escape through that port. The two illustrated upper reaction chamber ventilation ports 508 are positioned approximately equidistant above the bottom 510 of container 502.

A filter 512 is positioned in each upper ventilation port 508. In one implementation, the filters 512 are a woven or nonwoven material that allows water vapor or steam to pass through but prevents liquid from passing. The filters 512 may be either manufactured or treated in a particular way to produce such a characteristic. The material is typically nonwetting but permeable, so that water vapor can pass through but not liquid. Suitable materials with this property are well known. The filter 512 material may include one or more of the following materials: Gortex GAW 104 Polyester, Gortex 10 micron 12405072.3, Repel Treated Supor 1200-80730, Ernflon PTFE, Versapor 3012, Versapor 10000 R or TR, Versapor 5000 R or TR, Pallflex ® Emfab TX1040 or Timonium. Each filter 512 may be formed as a membrane that is a modified acrylic copolymer cast on a thin, non-woven polyester support. The membrane may then be FluoroRepel™ treated for superior oleophobicity/hydrophobicity. In one implementation, the filters 512 are applied to the upper ventilation ports 508 using an adhesive or an ultrasonic seal. Other methods of adhering the filters 512 to the upper reaction chamber so as to cover ventilation ports 508 are possible.

Each upper ventilation port 508 provides a path from the interior space of the sleeve 508 into an associated one of the ventilation passages 514. Each ventilation passage 514 is in fluid communication with the interior space via at least one of the upper ventilation ports 526. The ventilation passages 514 extend partially around a periphery of the container 502. In some implementations, the ventilation passages 514 are molded with the sleeve 508. In some implementations, the container 502 and the sleeve 508 are formed as separate elements and then brought together. In some implementations, the exit ports 516 may open into a common steam collection chamber (i.e., a plenum). The plenum may or may not vent to atmosphere. If the plenum vents to atmosphere, then the exit ports are formed in the plenum, not upper ventilation passages.

Typically, the exit ports 520 are covered, at least during shipping, with a mesh screen, for example, or some other covering to prevent external contaminants from entering the upper ventilation passages 514.

In the illustrated implementation, the two upper ventilation passages 514 are contiguous and extend around the entire circumferential periphery of the sleeve 508. The container 502 is annular in shape and is oriented horizontally and positioned near a top of the sleeve 508. The two exit ports 516 are at approximately diametrically opposite points on that container 502. Baffles 550 are provided inside the container 502 and act as fluid barrier between the upper ventilation passages 514.

When the illustrated heating device 500 is in an upright orientation and is producing more steam than can be condensed inside its reaction chamber, excess steam can escape through either one or both of the upper ventilation ports 526.

Furthermore, if the container 502 is on its side and the heating device 500 is generating more steam than can be condensed inside the reaction chamber, at least one of the two ventilation ports 526 will be sufficiently above the liquid line associated with the reactants to allow steam to escape through it. The excess steam that does escape through that ventilation port 526 travels approximately halfway around the periphery of the container through an associated ventilation passage 514, and exits through an associated exit port 516.

FIGS. 7 and 8 show another implementation of a heating device 700. Heating device 700 is similar to heating device 500 shown in FIG. 5. The primary difference is that heating device 700 has one upper ventilation passage 514 and one lower ventilation passage 714. The illustrated lower ventilation passage 714 is similar to the illustrated upper ventilation passage 514 except for the extension 730 that extends approximately perpendicularly downward toward the bottom edge 510 of the sleeve 508. That extension 730 is hollow and is in fluid communication with a lower ventilation port 726 that extends into the sleeve's interior space. The lower ventilation port 726 is at a location that is lower than the upper ventilation port 526. In some implementations, the lower ventilation port 726 also includes a filter (not shown).

The lower ventilation port 726 is positioned so that, if the container 502 is upside down, the lower ventilation port 726 will be above the liquid line associated with the reactants. Also, the lower ventilation port 726 is peripherally displaced from alignment with the upper ventilation port 526 by about 180 degrees.

The implementation of FIGS. 7 & 8 is adapted to vent excess steam properly regardless of whether the heating device 700 is upright, on its side or upside down.

A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention.

For example, the number of, the specific positioning of and the relative positioning of the upper and lower ventilation ports, the upper and lower ventilation passages, the plenum, and the exit ports can vary considerably. Moreover, the length of each upper and/or lower ventilation passage can vary considerably. The container could have a variety of shapes, including rectangular, oblong or any other shape suitable for a container.

Moreover, the shape and dimensions of the container, the shape and dimensions of the sleeve, and the relative arrangement of the container and the sleeve can vary considerably. For example, the sleeve can be coupled to the container in a number of ways, m some instances, the sleeve may be located outside the container.

In some implementations, a heating device can be implemented by coupling one or more tubes to a reaction chamber housing. For example, in some instances, the reaction chamber housing defines an interior space adapted to be in fluid communication with reactants from a user-initiated exothermic chemical reaction.

The housing has surfaces that respectively define a lower ventilation port between the interior space and a lower ventilation passage; and an upper ventilation port between the interior space and an upper ventilation passage. The tubes are coupled to the sleeve and have surfaces that define the upper ventilation passage and the lower ventilation passage. The upper and lower ventilation passages extend at least partially around a perimeter of the sleeve. The tubes also have surfaces that define exit ports facilitating fluid communication between the upper and lower ventilation passages and outside, hi some implementations, the lower ventilation port is peripherally displaced from alignment with the upper ventilation port, hi some implementations, the lower ventilation port is at a peripherally opposite position from alignment with the upper ventilation port. The tubes can be inside or outside the housing.

The term "tube" should be construed broadly to include tubing, pipes, channels, etc. The tubes can be made of any suitable material. They may be flexible or rigid. The exit ports need not be at the same heights as long as they are positioned in a manner that enables steam to exit the heating devices in a manner than is consistent with the concepts described herein. hi some implementations, the heating device includes as few as one upper and one lower ventilation ports. However, particularly in those instances, it is preferable that, at least one of the upper ventilation ports is peripherally displaced from alignment with at least one of the lower ventilation ports. It is further preferable that, at least one of the upper ventilation ports is at about a peripherally opposite position from alignment with the upper ventilation port. hi some implementations, the heating device can include as few as two upper and no lower ventilation ports. Particularly in those instances, it is preferable that, the upper ventilation ports are peripherally displaced from one another. Moreover, it is preferable that, at least two of the upper ventilation ports are at about peripherally opposites from one another.

Moreover, details of the heating device and its operations can very considerably. For example, the activation mechanism may be different, the chemistry associated with the exothermic chemical reaction may be different, the specific way in which the various elements are assembled may be different.

Additionally, thermal insulation typically is applied to the heating devices disclosed herein to thermally insulate, for example, the heating device's reaction space and to help ensure that a user is not harmed when handling the heating device during use.

Accordingly, other implementations are within the scope of this application and the following claims.

Claims

What is claimed is:

1. A heating device comprising: a sealed container; a sleeve coupled to the container, the sleeve defining an interior space adapted to be in fluid communication with reactants from a user-initiated exothermic chemical reaction; the sleeve having surfaces that respectively define: a lower ventilation port between the interior space and a lower ventilation passage; and an upper ventilation port between the interior space and an upper ventilation passage; the sleeve and the container having surfaces that cooperatively define the upper ventilation passage and the lower ventilation passage, wherein the upper and lower ventilation passages extend at least partially around a perimeter of the sleeve; the container having a surface that defines an exit port facilitating fluid communication between the upper and lower ventilation passages and outside.

2. The heating device of claim 1 wherein the lower ventilation port is peripherally displaced from alignment with the upper ventilation port.

3. The heating device of claim 3 wherein the lower ventilation port is at a peripherally opposite position from alignment with the upper ventilation port.

4. The heating device of claim 1 wherein the upper ventilation port is so positioned that, when the heating device is operated in an upright position, the upper ventilation port is above a liquid line associated with the reactants.

5. The heating device of claim 1 wherein the lower ventilation port is so positioned that, when the heating device is operated upside down, the lower ventilation port is above a liquid line associated with the reactants.

6. The heating device of claim 1 wherein the upper and lower ventilation ports are so positioned that, when the heating device is operated on its side, at least one of the upper or lower ventilation ports is above a liquid line associated with the reactants.

7. The heating device of claim 1 comprising: at least two upper ventilation ports at about peripherally opposite locations from one another; and at least two lower ventilation ports at about peripherally opposite locations from one another, wherein the upper ventilation ports are peripherally displaced from alignment with the lower ventilation ports by about 90 degrees.

8. The heating device of claim 1 wherein the sleeve and the container have surfaces that cooperatively define a plenum between and in fluid communication with the upper ventilation passage and the lower ventilation passage, wherein the exit port enables fluid communication directly from the plenum to outside.

9. The heating device of claim 8 wherein the upper and lower ventilation passages extend from respective upper or lower ventilation ports, approximately halfway around the perimeter of the sleeve, to the plenum.

10. The heating device of claim 8 wherein the sleeve comprises: an outer surface that is in contact with an inner surface of the container; and grooves formed in the outer surface to define the upper and lower ventilation passages and the plenum.

11. The heating device of claim 1 further comprising: a product container nested within the sleeve, the product container containing a product that is adapted to absorb heat generated by the exothermic chemical reaction.

12. The heating device of claim 11 further comprising a fusible material containing reaction suppressant adhered to a reaction-chamber side of a common wall between the product container and the reactants.

13. The heating device of claim 11 further comprising: a frangible seal below the sleeve and initially separating reactants for the exothermic chemical reaction, wherein the product container is movable so as to break the frangible seal, thereby causing the reactants to mix and the exothermic chemical reaction to be initiated.

14. The heating device of claim 13 wherein the reactants comprise: a first reactant, in a liquid form, initially located above the frangible seal; and a second reactant, in a high surface are solid form, initially located below the frangible seal; wherein when the frangible seal is ruptured, the liquid first reactant flows downward into the second reactant.

15. The heating device of claim 1 further comprising: a deformable upper seal around the sleeve between the upper ventilation port and the upper ventilation passage; and a deformable lower seal around the sleeve between the lower ventilation port and the lower ventilation passage, wherein the sleeve is movable between: a first position where the deformable upper and lower seals are sealed against an inner surface of the container and respectively impede fluid communication between the upper ventilation port and the upper ventilation passage and between the lower ventilation port and the lower ventilation passage, respectively; and a second position where the deformable upper and lower are deformed by contacting one or more features on the inner surface of the container so as to not impede fluid communication either between the upper ventilation port and the upper ventilation passage or between the lower ventilation port and the lower ventilation passage, respectively.

16. A heating device comprising: a sealed container; a sleeve coupled to the container, the sleeve defining an interior space adapted to be in fluid communication with reactants from a user-initiated exothermic chemical reaction; the sleeve having surfaces that define upper ventilation ports between the interior space and one or more upper ventilation passages, the upper ventilation ports being peripherally displaced from one another around the sleeve; the sleeve and the container having surfaces that cooperatively define the one or more upper ventilation passages, each of which extends at least partially around a periphery of the sleeve; the container having a surface that defines an exit port adapted to facilitate fluid communication between the one or more ventilation passages and outside.

17. The heating device of claim 16 wherein the sleeve has a surface that defines a lower ventilation port that is peripherally displaced from alignment with the upper ventilation port.

18. The heating device of claim 17 wherein the lower ventilation port is at a peripherally opposite position from alignment with the upper ventilation port.

19. The heating device of claim 17 wherein the lower ventilation port is so positioned that, when the heating device is operated upside down, the lower ventilation port is above a liquid line associated with the reactants.

20. The heating device of claim 17 wherein the upper and lower ventilation ports are so positioned that, when the heating device is operated on its side, at least one of the upper or lower ventilation ports is above a liquid line associated with the reactants.

21. The heating device of claim 17 wherein the sleeve and the container have surfaces that cooperatively define a plenum between and in fluid communication with at least one of the upper ventilation passages and at least one of the lower ventilation passages, wherein the exit port enables fluid communication directly from the plenum to outside.

22. The heating device of claim 16 further comprising: a product container nested within the sleeve, the product container containing a product that is adapted to absorb heat generated by the exothermic chemical reaction.

23. The heating device of claim 22 further comprising a fusible material containing reaction suppressant adhered to a reaction-chamber side of a common wall between the product container and the reactants.

24. The heating device of claim 22 further comprising: a frangible seal below the sleeve and initially separating reactants for the exothermic chemical reaction, wherein the product container is movable so as to break the frangible seal, thereby causing the reactants to mix and the exothermic chemical reaction to be initiated.

25. The heating device of claim 22 wherein the reactants comprise: a first reactant, in a liquid form, initially located above the frangible seal; and a second reactant, in a high surface area solid form, initially located below the frangible seal; wherein when the frangible seal is ruptured, the liquid first reactant flows downward into the second reactant.

26. A vent system for a reaction chamber adapted to contain an exothermic chemical reaction, the vent system comprising: a sleeve defining the reaction chamber; upper reaction chamber openings formed in the sleeve and peripherally displaced from one another around the sleeve; a vent passage coupled to each upper reaction chamber opening, wherein the vent passages extend peripherally about the sleeve; and an external opening formed in each vent passage, wherein each external opening is peripherally displaced from an associated one of the upper reaction chamber openings.

27. The vent system of claim 26 further comprising a filter coupled to each upper reaction chamber opening, wherein each filter is adapted to: enable vapor to pass between the reaction chamber and an associated one of the vent passages; and prevent liquid from passing between the reaction chamber and the associated one of the vent passages.

28. The vent system of claim 26 wherein a first one of the upper reaction chamber openings is formed at a substantially opposite position in the sleeve as a second one of the upper reaction chamber openings.

29. The vent system of claim 26 wherein a first one of the external openings is formed at a substantially opposite position relative to the sleeve as a second one the external openings.

30. The vent system of claim 26 wherein the vent passages form a ring- shaped container that extends around an entire perimeter of the sleeve.

31. The vent system of claim 30 further comprising a baffle positioned inside the ring-shaped container to separate a first one of the vent passages from a second one of the vent passages.

32. The vent system of claim 30 further comprising: a lower reaction chamber opening formed in the container at a position lower than the upper reaction chamber openings; wherein at least one of the vent passages includes an extension that extends approximately perpendicularly downward to fluidly communicate with the lower reaction chamber opening.

33. The vent system of claim 32 wherein the lower reaction chamber opening is formed at a position in the container such that, if the container were upside down, the lower reaction chamber opening would be above a liquid line in the reaction chamber.

34. A method of venting excess steam from an exothermic chemical reaction occurring in a portable heating device, the method comprising: providing a heating device comprising: a sealed container; a sleeve coupled to the container, the sleeve defining an interior space adapted to be in fluid communication with reactants from a user-initiated exothermic chemical reaction; the sleeve having surfaces that respectively define: a lower ventilation port between the interior space and a lower ventilation passage; and an upper ventilation port between the interior space and an upper ventilation passage; the sleeve and the container having surfaces that cooperatively define the upper ventilation passage and the lower ventilation passage, wherein the upper and lower ventilation passages extend at least partially around a perimeter of the sleeve; the container having a surface that defines an exit port facilitating fluid communication from the upper and lower ventilation passages and outside; initiating the exothermic chemical reaction; and enabling excess steam from the exothermic chemical reaction to exit the heating device via at least one of the upper or lower ventilation ports, an associated one or more of the upper or lower ventilation passages and the exit port.

35. A heating device comprising: a reaction chamber housing adapted to be in fluid communication with reactants from a user-initiated exothermic chemical reaction; the reaction chamber housing having surfaces that respectively define: a lower ventilation port between the chamber and a lower ventilation passage; and an upper ventilation port between the chamber and an upper ventilation passage; tubes coupled to the reaction chamber housing and having surfaces that define the upper ventilation passage and the lower ventilation passage, wherein the upper and lower ventilation passages extend at least partially around a perimeter of the sleeve; the tubes having respective surfaces that define exit ports that facilitate fluid communication between the upper and lower ventilation passages and outside.

36. The heating device of claim 35 wherein the lower ventilation port is peripherally displaced from alignment with the upper ventilation port.

37. The heating device of claim 36 wherein the lower ventilation port is at a peripherally opposite position from alignment with the upper ventilation port.

38. The heating device of claim 35 wherein the tubes are inside the housing.

39. The heating device of claim 35 wherein the tubes are outside the housing.