Patent Application
20250160558
The present disclosure relates to cooking equipment and more particularly to cooking devices designed for outdoor use.
Many outdoor camping stove systems, particularly those carried by backpackers, are designed to have a small size when packed and typically include a cooking pot that tightly contains everything needed to heat water quickly and efficiently, including the stove and the fuel. Such systems are typically designed for heating water and thereafter cooking food, typically freeze-dried meals, for 1-2 people. Such systems typically have a small pot having a diameter of 3.5 in/90 mm that can store a stove and a 4 oz liquid petroleum gas (LPG) fuel canister.
Some so-called “high efficiency” cooking pots used for such stove systems include a flat-bottomed pot that includes a heat exchanger on the bottom of the pot. The atmospheric burner of the stove system draws primary atmospheric air into the stove, mixes it with the fuel, and ignites the fuel/air mixture as it exits the burner, where it mixes with more secondary atmospheric air to complete the combustion process. The resulting flames contact the bottom of the pot and the heat exchanger, which includes fins that are directly in contact with the flames. The interaction between the heat exchanger fins and the flames can disrupt the complete combustion of the flame. Further, as the heat exchanger fins are intended increase the heat at the cooking surface, such pots may limit the stove system's ability to cook foods on low heat or at a simmer. Also, as a slight breeze in an outdoor environment can extinguish the stove's flame when operating at low output, the user may be required to either compensate by increasing the output or constantly reigniting the stove. The heat exchanger fins can also result in too much heat being focused at certain spots, i.e., hot spots, within the pot that correspond to the locations of the fins. Hot spots are created on the cook surface where the fins are thermally connected to the pot. Food can burn at these hot spot locations and make it more difficult to clean the pot after use.
Stove systems with radiant burners use 100% primary air combustion to safely work with a cooking pot that includes a heat exchanger. In a radiant burner system, the flame output lives on the surface of the stove's burner and does not come out of the burner and therefore the flame does not impinge on the fins of the pot's heat exchanger in a way that disrupts combustion. Radiant burner systems have a limited turn-down ratio, which refers to the lowest output at which combustion can be maintained, thus limiting the system's ability to cook food at low heat or at a simmer. Such stove systems can also be expensive. To achieve a slim profile, i.e., stove height, a low weight, and proper combustion at a high output, a thixomolded body, of magnesium or aluminum, that incorporates fuel delivery, jets and horizontal mixer tubes may be required. These requirements further increase the cost over a more standard stove. In addition, since radiant burner stoves are prone to burn back or flash back (an event where the flame propagates inside the stove), a thermal trip may be required to shut off the fuel source, which further adds to the cost of the stove system.
Accordingly, there is a need for an economical, lightweight, and compact stove system that can safely heat water quickly and efficiently while also being able to cook food at low heat settings, including a simmer.
A cooking assembly is disclosed that includes a pot having cylindrical vertical sides, an open circular top and a closed rounded bottom and a cylindrical containment ring positioned around a portion of the pot that creates a containment volume between the containment ring and the pot, the containment ring including an open circular bottom configured to interface with a portable stove, to hold the pot in a vertical orientation, and to let flame from the portable stove and air to flow freely into the containment volume so as to reduce back pressure, the containment further including a plurality of vent holes at an upper area of the containment volume configured to let combustion gases escape freely
There may be a containment volume 7, as shown by the hashed lines of
The vent holes 4 between the bottom 9 of the pot 1 and the containment ring 2 allow combustion gas in the containment volume 7 to exit at the top of the containment ring 2. As noted above, the addition of a sufficiently large opening 5 in the bottom of the containment ring 2 permits flame from the stove burner and atmospheric air to flow freely into the containment volume 7. It should be noted that if there is too much back pressure in the containment volume 7, the bulk of the flame and air will not fully enter the bottom of the ring through the opening 5, thereby causing the flame and air to stagnate or be trapped and flow back out and around the bottom entrance 5 of the ring. This can disrupt combustion and greatly reduce the efficiency of the stove system, thereby greatly increasing boil time. For a backpacker, where winds are common, it is highly desirable to have the most efficient stove system to reduce the weight of the fuel needed and so the boil time is as low as possible.
The webs 6 of the containment ring 2 formed between each of the holes 4 may need to be far enough from where flame from the stove impinges the bottom 9 of the pot 1 so the webs 6 do not impinge the flame. Impinging the flame at the webs 6 may disrupt the combustion reaction, thereby causing unsafe levels of carbon monoxide (CO). The webs 6 need to have sufficient cross section so as to enable sufficient heat transfer from the containment ring 2 material below the webs 6 to the welds 3 above the webs 6. Likewise, the thermal connection between the containment ring 2 and the pot 1 must also provide sufficient heat transfer so as to fully take advantage of the containment ring 2 being thermally connected, thereby increasing thermal efficiency, and in some cases to prevent the containment ring 2 from getting too hot. The containment ring 2, along with its opening 5, also allows for the pot 1 to be set down on its rim 10 without falling over and allows it to be put on the top of a stove 11.
In order to maintain an overall stove system with a small-packed size, as partly illustrated in
As shown in
The pot interface/mounts 15 do not fold such that they purposely interface with the pot 1 so as to reduce user interaction in deploying and storing the stove 11 within the pot 1. When stored, the mounts, burner and fuel canister of the stove are designed to fit within or at least partially within the pot; and when in operation, are assembled under the bottom of the pot. However, when the stove system is intended to be used with cookware other than the pot 1, the mounts 15 include legs 54 that can fold out and be used to support the other cookware. The stove 11 also includes a threaded interface 16 for coupling with the LPG fuel canister 72 (as shown in
As illustrated in
As noted herein, the fuel/primary air mixture is combusted as it exits the burner where it mixes with secondary air completing the combustion reaction. The chemical reaction of combustion is still occurring while the flame is traveling along the pot bottom. If the pot is relatively smooth and far enough away from the burner, the bulk of the combustion reaction is not disturbed, such as by the fins of a heat exchanger, and thus the combustion products have low CO. Replacing a flat bottomed pot with a hemispherically shaped pot allows the flame to enter the opening 5 in the bottom of the containment ring 2, create volume for combustion, and increase the surface area in contact with the flame, thereby enabling a fast boil that is more efficient.
The hemispherical shape of the pot also reduces the amount of welds that are required, thereby making it less expense to manufacture the stove system. Pots that have heat exchangers consisting of an array of fins usually have the fins welded or brazed to the pot. Such fins may include a corrugated heat exchanger ribbon that is typically welded between each corrugation.
In addition to requiring more welds and potentially leading to more CO caused by the flames' interaction with the fins, so-called “high efficiency” stove systems produce intense heat at the bottom of the pot, which may produce a fast water boil, but also makes it difficult to cook food at a low temperature or simmer. The combination of the hemispherical pot 1 and containment ring 2, however, cooks more like a normal cooking pot which makes it possible to cook at lower temperatures, including a simmer. If there is a breeze, the output of the stove can be increased without overheating the cooking surface. By allowing combustion to occur at the bottom of the pot and the containment volume 7 around a portion of the side, the localized hot spots created by excessive heat being generated at the welds between the heat exchanger fins and the pot, are eliminated. This reduces food burning and sticking to the bottom of the pot, thereby making the pot easier to clean. As the welds between the containment ring 2 are much higher along the side of the pot 1, as long as the food volume is below those locations, food may not stick to the pot 1.
For typical high efficiency stove systems, the burner typically produces a vertical, small diameter flame so that the burner puts as much heat in the center of the pot as possible so as to maximize dwell time of the flame and to exhaust gas as it travels outward along the bottom of the pot. With flat bottomed pots, the higher the surface area (up to a point) the higher the efficiency of the pot. If the flame is too large on a small diameter, flat bottomed pot, the flame will simply shoot outward past the pot diameter and the energy contained in the unutilized flame will be wasted, thereby reducing efficiency.
With a hemispherical pot, there is two times as much surface area relative to the planar circle of a traditional flat bottom pot. This significantly increases the contact time between the flame and hot exhaust gas, which decreases boil time and increases efficiency. In addition, flame directed at the center of a hemisphere follows the bottom to the sides, instead of shooting outward past the bottom of a flat-bottomed pot. Since the flame and exhaust gas follow the shape of the hemisphere up the sides, it further increases its flame contact area, thereby boiling water faster and increasing efficiency, when compared to a flat bottom pot.
A cauldron has a hemispherical bottom, but no containment ring. By adding a containment ring to a cauldron, prolonged heat input is enabled, while reducing boil time and efficiency, and also enabling the hemispherical bottom to sit on a flat surface and not fall over. In addition, as the containment ring 2 is made from a conductive material and is thermally connected to the pot 1, it collects heat from the flame and hot exhaust gas through radiation and convection and transfers that heat through conduction to the pot 1, and therefore its contents. Alternatives to welding the containment ring to the pot include brazing, shrink-fitting or clamping of the containment ring 2 to the pot 1, each of which may also be thermally connect the ring to the pot.
As noted herein, the pot 1 is make from a conductive material. Ideally, the pot 1 is constructed of thin, low density, high thermal conductive material with lower heat capacity and lower specific heat, such as aluminum, which reduces the losses and has a high heat transfer rate. It also reduces the weight of the stove and pot combination. Further, if the pot 1 is darker in color, such as anodized aluminum, it will have a higher emissivity and therefore adsorb more electromagnetic radiation in the form of heat. In other words, the darker colored pot material will collect more heat, in the form of light given off from the flame or anything else that is hot. This is true even for hot objects that do not emit visible light because heat transfer can still occur through radiation, such as from infrared light.
Although the pot has been described herein as hemispherical, other shapes may achieve similar results in terms of boil time and efficiency, including ellipsoidal, paraboloid, or combinations of radii or shapes which generally create a round pot that allows flames and hot exhaust to transfer heat along its bottom and sides and when combined with a containment ring 2 are still highly efficient and safe. A number of embodiments are provided in
As noted above, the pot 1 may be designed for a stove system using a 4 oz LPG fuel canister. The pot illustrated in
Additional pot shapes are illustrated in
The pot 26 as illustrated in
The pot 27 of
The pot 33 and containment ring 34 of
The pot 36 and shroud 37 of
The pot 39 and shroud 40 of
Further embodiments, not shown per se, but represented via different combinations of the components of the embodiments that are illustrated in
In a further embodiment, the pot may have a hemispherical bottom with no annular area (i.e., not a step in either the pot or the shroud) between the shroud and the pot such that the shroud is tight to the pot diameter.
In another embodiment, the pot may have a hemispherical bottom with a shroud that has an annular area between the pot and the shroud, but with no step in the pot or the shroud, but connected by some other means than welds, etc., such as by tabs that bend in on the shroud or some other means of attachment.
In an embodiment, a cooking assembly, comprising: a pot having cylindrical vertical sides, an open circular top and a closed at least partially rounded bottom; and a cylindrical containment ring positioned around a portion of the pot creating a containment volume between the containment ring and the pot, the containment ring including an open circular bottom receiving a portable stove when configured for cooking, holding the pot in a vertical orientation, and letting flame from the portable stove and air to flow freely into the containment volume so as to reduce back pressure and increase heating efficiency, without disrupting combustion reactions; the containment ring further including a plurality of vent holes at an upper area of the containment volume letting combustion gases escape freely.
In the embodiment, wherein the vent holes are formed below a connection between the pot and the containment ring.
In the embodiment, wherein the containment ring includes a plurality of webs, each web among the plurality of webs formed between the vent holes, and wherein the plurality of webs does not impinge the flame from the portable stove.
In the embodiment, wherein the webs have a cross-sectional area sufficient to enable heat transfer from the entirety of the containment ring to the pot.
In the embodiment, wherein the containment ring is thermally and structurally connected to the pot to promote heat transfer.
In the embodiment, wherein the containment ring is structurally connected to the pot by a series of welds.
In the embodiment, wherein the containment ring is structurally connected by a tight fit between the containment ring and the pot.
In the embodiment, wherein the containment ring is structurally connected to the pot by at least one of a series of welds and a tight fit between the containment ring and the pot.
In the embodiment, wherein an outer diameter of the pot steps down to create an annular space near the upper area of the containment volume.
In the embodiment, further comprising a plurality of fins within the annular space below the plurality of vent holes.
In the embodiment, wherein the portable stove includes a mount connected to a pot interface ring that interfaces with the pot and promotes location of the pot between the plurality of mounts.
In the embodiment, wherein the mounts are rigid and do not fold.
In the embodiment, wherein the containment ring steps down in diameter from a first diameter of an upper portion of the containment ring to a second diameter of a lower portion of the containment ring.
In the embodiment, wherein the lower portion of the containment ring includes a plurality of air openings.
In the embodiment, further comprising an insulated collar that surrounds an upper portion of the pot and a handle.
In the embodiment, wherein the containment ring includes a plurality of air holes at the upper portion of the containment ring under the handle reducing back pressure and exhaust exiting the containment volume in an area under the handle.
In the embodiment, wherein the pot and the containment ring are formed of anodized aluminum.
In the embodiment, wherein the at least partially rounded bottom has a shape that is one of hemispherical, ellipsoidal, paraboloid, and a combination thereof.
In the embodiment, wherein the rounded bottom includes a plurality of raised bumps on a surface of the rounded bottom.
In the embodiment, wherein the rounded bottom includes a plurality of indented dimples on a surface of the rounded bottom.
In the embodiment, wherein the rounded bottom includes a plurality of curved grooves on a surface of the rounded bottom.
In the embodiment, wherein the rounded bottom includes a plurality of curved protrusions on a surface of the rounded bottom.
In the embodiment, wherein the containment ring includes a series of flow channels between the containment volume and outer sides of the containment ring for hot exhaust gas to travel along a longer flow path.
In the embodiment, wherein the containment ring is configured to slide up and down along the vertical sides of the pot and includes a latch assembly for securing the containment ring to the vertical sides of the pot.
In the embodiment, wherein the containment ring includes a plurality of fins at the open circular bottom of the containment ring that radiate outward from a smaller diameter central area.
Conditional language used herein, such as, among others, “can,” “could,” “might,” “may,” “e.g.,” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements, and/or steps. Thus, such conditional language is not generally intended to imply that features, elements and/or steps are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without author input or prompting, whether these features, elements and/or steps are included or are to be performed in any particular embodiment. The terms “comprising,” “including,” “having,” and the like are synonymous and are used inclusively, in an open-ended fashion, and do not exclude additional elements, features, acts, operations, and so forth. Also, the term “or” is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term “or” means one, some, or all of the elements in the list.
The present disclosure describes particular embodiments and their detailed construction and operation. The embodiments described herein are set forth by way of illustration only and not limitation. Those skilled in the art will recognize, in light of the teachings herein, that there may be a range of equivalents to the exemplary embodiments described herein. Most notably, other embodiments are possible, variations can be made to the embodiments described herein, and there may be equivalents to the components, parts, or steps that make up the described embodiments. For the sake of clarity and conciseness, certain aspects of components or steps of certain embodiments are presented without undue detail where such detail would be apparent to those skilled in the art in light of the teachings herein and/or where such detail would obfuscate an understanding of more pertinent aspects of the embodiments.
The terms and descriptions used above are set forth by way of illustration only and are not meant as limitations. Those skilled in the art will recognize that those and many other variations, enhancements and modifications of the concepts described herein are possible without departing from the underlying principles of the invention. The scope of the invention should therefore be determined only by the following claims and their equivalents.
