Patent ID: 12201236

DETAILED DESCRIPTION

A portable sous vide cooking appliance that does not require a motor to physically move water or have its own container is provided. The portable sous vide cooking appliance may be used with a separate stock pot or other container holding water. Unlike immersion circulators, in one embodiment of the sous vide cooking appliance, only the heating element and its protected conduit to supply power make contact with the water in the sous vide water bath. The sous vide cooking appliance requires no water circulators to function. The sous vide cooking appliance described requires no electric motor, no impeller pump, no water intakes and no water outtakes. Further, unlike immersion circulators, the sous vide cooking appliance passively circulates water through convection currents and are not required to actively agitate the water bath, creating noise and more evaporation and steam.

The sous vide cooking appliance includes a control unit with a control panel and electronics, as well as a power connection to a heating element and a temperature sensor. In another embodiment, the control panel and electronics are in a separate self-contained unit outside of the cooking container connected with a cord. A PID (Proportional Integral Derivative) controller in the control unit in conjunction with the temperature sensor and heating element are used to accurately control the temperature of the cooking water. In one embodiment, the sous vide cooking appliance hooks on to the side of the cooking container, and in another embodiment the control unit is separate from the cooking container and self-contained.

The portable sous vide cooking appliance is effectively a free-standing PID heating unit using only convection currents as opposed to motors to circulate water. Contrarily, the immersion circulators (typically shaped like a wide stick) require an impeller pump or some other way to move the water over the small heating element located in the tube of the immersion unit. If they have no way to circulate the water, they cannot heat the water evenly. The portable sous vide cooking appliance uses a heating element that covers the bottom of whichever container users choose to use. In one implementation, a number of different interchangeable heating elements can be plugged into the control unit so that the heating elements are sized according to the size of the container. Since the heating element covers substantially the entire base of the container in which the water resides and the food cooks, a convection current is generated that keeps the water temperature constant throughout, and does so without its own insulated container. The user provides their own cooking pot, container or basin.

Several different-sized heating elements can be plugged into the control unit. Users may use the heating element(s) based on what size container they plan to cook in. These different-sized heating elements may run by the same control unit, and the control unit may drive varying sizes of heating elements. This is in contrast to both baths and immersion circulators which have a control unit that drives only one size heating element, which is the heating element included with the unit.

FIG.1Ashows a sous vide cooking appliance100with four main parts, a control unit102, a conduit104(carrying power), a silicone-encased resistance heating element106and a temperature sensor108. In one embodiment, the control unit102contains a Printed Circuit Board (PCB) and a control chip or processor with a PID algorithm programmed therein. The control unit102may also have a memory having software for implementing processes described herein. The sous vide cooking appliance100may be operated through a touch screen, buttons on a control panel110or other suitable input. In one embodiment, the control unit102has a generally cylindrical housing with a slanted top. The electronics of the control unit102are inside the housing. In one embodiment, the control panel110is located on the top of the control unit. The electrical power comes into the power source in the control unit102via a power cord114and is reduced to 5V to run the electronics while shunting full power to the heating element106. The sous vide cooking appliance100may be 110V, 220V or dual-voltage. The sous vide cooking appliance100can include other boards, chips, display drivers and interfaces. The sous vide cooking appliance100maintains consistent water temperature in a water bath, for example, to within 0.5 degrees for extended cooking times. In some embodiments, the control unit102is programmable and includes a timer.

The sous vide cooking appliance100may be sized as a hand-held and is portable for easier storage in kitchen cabinets. Users use their water container112, such as a stock pot, to cook with the sous vide cooking appliance100. Because convection current water flow is created by the sous vide cooking appliance100, the exemplary appliance shown inFIG.1Adoes not forcibly circulate water. No pump or impeller is required for the sous vide cooking appliance100to properly operate. A conduit104running from the control unit102to the heating element106carries the electric wire or cord (electricity) to the heating element at the bottom.

In some embodiments, the conduit104is flexible and in others it is hard or stiff. In some embodiments, the conduit104is adjustable, for example it may telescope or otherwise change in length. By changing length, the conduit104is able to adapt the sous vide cooking appliance100to pots or other containers112of differing height. The conduit104is made from for example a plastic, aluminum, steel stainless steel, rubber, etc. In one embodiment, a plastic tube is used. In yet another embodiment, a tube within a tube design is used to allow telescoping of the conduit104. In some embodiments, the conduit104would be water tight.

Temperature sensors108are used by the sous vide cooking appliance100to control the temperature of water in the stock pot or other cooking container112. In some embodiments, multiple temperature sensors108are used (e.g., two, three, four, etc.). The temperature sensors108may be located in different positions while still being connected to provide or feed data to the PID controller (not shown) in the control unit102. For example, in one embodiment, the temperature sensor108can be outside the conduit104and in contact with the water of the water bath (shown inFIG.1B). In some embodiments, the temperature sensor(s)108are located inside the conduit104to monitor the temperature of the water bath and send temperature information back to the PID controller to maintain the constant temperature required for sous vide cooking. In these embodiments, the temperature sensor108does not directly contact the water. To accommodate the temperature sensor's lack of contact with the water, a temperature adjustment algorithm is used. The temperature is adjusted from an inside the conduit temperature to the actual water temperature of the water bath. A detailed description of the PID controller and temperature measurements is disclosed in U.S. Pat. No. 9,220,362 issued Dec. 29, 2015, which is incorporated by reference herein.

During manufacture or set-up, using a separate device, temperature readings are taken of the water while readings are taken with the temperature sensors108of the sous vide cooking appliance100. The actual water temperature readings are entered into the sous vide cooking appliance100and the PID controller adjusts the temperature sensor readings to account for the lack of contact with the water. By indirectly taking the water temperature, the temperature sensors108may be protected from the water and the elements providing greater reliability and longer life cycle for the temperature sensor components. Because the temperature sensor(s)108do not have direct contact with the water inside the water bath, the temperatures measured by the temperature sensor(s)108are typically different from the actual water temperature inside the pot by a margin of a fraction of a degree Fahrenheit to several degrees Fahrenheit or possibly more, depending on the thermal conductivity of the protective material surrounding the temperature sensor(s)108(e.g., flexible conduit, wrapping, retractable reel housing and the location of the temperature sensor). Temperature adjustment or conversion factors k1. . . knare experimentally determined for each configuration and individual temperature sensor(s)108so that the measured temperature (MT) reflects the actual water temperature in the pot. Therefore, the temperature determination algorithm allows for precise measurement and control of the water cooking temperature.

In one embodiment, a button control program allows the manufacturer to program the PID controller through a series of tests so that the displayed temperature reflects the actual water temperature inside the cooking chamber. In one embodiment, the PID controller is initialized at three temperature settings, for example: setting A=30 degrees C., setting B=60 degrees C., and setting C=90 degrees C. Briefly, an exemplary water bath is filled, and the PID controller is set at a cooking temperature of 30 degrees C. After the setting temperature is reached on the PID display (i.e., the temperature measured by the temperature sensor is 30 degrees C.), the actual water temperature of the water bath is measured directly by placing a reference thermometer inside the water. The difference between the displayed temperature (i.e., the temperature measured by the temperature sensor108) and the measured temperature (i.e., the actual water temperature measured with the reference thermometer) at the 30 degrees C. setting is entered and stored on a memory chip inside the PID controller or other memory device. This process is repeated at the temperature settings of 60 degrees C. and 90 degrees C. The stored temperature differences, referred to as adjustment values “A,” “B” and “C” for adjustment made at 30 degrees C., 60 degrees C. and 90 degrees C., respectively, are then used by the PID controller to achieve precise control of the cooking temperature in future temperature control cycles.

Temperature measured by the temperature sensor108is changed from an analog signal to a digital value by the sensor A/D detection, and the control unit102calculates the actual cooking temperature of the water bath by using the temperature offset program using a temperature adjustment algorithm and the stored “A,” “B,” and “C” adjustment values. In one embodiment, the temperature correction algorithm creates a temperature adjustment curve using the stored adjustment values. The temperature adjustment curve can be created with a straight-line method, a best fit method or any other method commonly known in the art. For each measured temperature Tm, the curve provides a temperature adjustment value Td. The temperature correction algorithm then calculates actual temperature value Tausing the formula Ta=Tm+Td.

In one embodiment, the temperature adjustment program calculates the difference Ekbetween the setting temperature and the calculated actual temperature Taand calculates the proportion and differential items. The program then decides whether the control value (i.e., the output of the PID controller) of the previous calculation U(k-1)is greater than the maximum value of the output of the PID controller in prior iterations Umax. If U(k-1)is not greater than Umax, the program then decides whether U(k-1)is smaller than the minimum value of the output of the PID controller in prior iterations Umin. If U(k-1)is smaller than Umin, the program decides whether Ekis smaller than zero. If Ekis not smaller than zero, the program calculates a new integral item and then the new control value Ukbased on the calculated proportion, differential and integral items. If Ekis smaller than zero, the program bypasses the routine. If U(k-1)is greater than Umin, the program calculates a new integral item and then the new control value Ukbased on the calculated proportion, differential and integral items.

If U(k-1)is greater than Umax, the program then decides whether Ekis greater than zero. If Ekis not greater than zero, the program calculates a new integral item and then the new control value Ukbased on the calculated proportion, differential and integral items. If Ekis greater than zero, the program bypasses any unnecessary program steps.

The heating element106is controlled based on the control value Uk. A program provides an audio signal to the user if for example, over-heating is detected or if the set cooking time is reached.

In some embodiments, the PID controller uses a temperature correction algorithm that implements a temperature conversion factor. In some embodiments, the temperature conversion factor is not a fixed offset. Using the PID controller, the temperatures measured by the one of more temperature sensors reflect actual water temperature in the pot within 0.5 degrees Celsius.

A description of the temperature adjustment algorithm and PID controller is found in U.S. Pat. No. 9,220,362 issued Dec. 29, 2015 which is incorporated by reference herein. Temperature adjustment algorithms are also deployed, for example, in the Sous Vide Supreme® Oven product sold by Eades Appliance Technology, LLC in the United States and Europe.

In some embodiments, the upper end of the conduit104is connected to the control unit102and the lower end or bottom of the conduit is connected to a silicone-coated heating element106. The heating element106is configured to cover a substantial part or all of the bottom of a container112which may be a standard stock pot, for example. Generally, the more area of the bottom of the stock pot covered by the heating element, the more even the heating. The heating element106creates convection currents throughout the water in the pot or cooking container112.

In some embodiments, the sous vide cooking appliance100includes a connection or hinge at the point in which the heating element connects to the conduit104. Various types of connections and hinges between the conduit104and heating element106may be used. For example, the connection may comprise one or more of joint, ball and socket joint, saddle joint, butt hinge, double hinge, T-hinge, pintle hinge, strap hinge, pivot and swivel hinge. In some embodiments, the connector or hinge enables the sous vide cooking appliance100to fold so that the heating element106swivels or folds toward the conduit104and the control unit102. The sous vide cooking appliance100may be folded for ease of storage, transport and packaging.

Referring toFIG.1B, a sous vide cooking appliance100is shown in use with an uncovered container112(e.g., stock pot) filled with water. The control unit102sits at the approximate height of the pot lip or lid. In some embodiments, the control unit102sits above the water and is not submersed. In other embodiments, the control unit housing is in contact with the water and may also include a temperature sensor108. A clip helps to hold and steady the control unit housing. In some embodiments, the clip is a square bracket. Other shapes for the clip may be used.

The heating element106is shown at the bottom of the container112with the power conduit104extending vertically from the control unit102to the heating element. A connector holds the hard conduit104to the heating element106. A temperature sensor108is shown mounted to the outside of the hard conduit104.

Convection currents are schematically shown moving upwards from the heating element106with curvy lines forming rays with arrow heads. In some embodiments, the heating element106may be constructed with various holes in it which make installation in a pot full of water easier. The heating element106may also be configured with feet or supports204allowing water to be below or underneath the heating element. Configurations of the heating element106with supports204and holes402enhances the convection circulation. In one implementation, the holes402may be a single hole. Since the heating element106of the sous vide cooking appliance100will create convection currents with or without holes402(shown onFIG.4) and supports204(shown onFIGS.2A and2B,) the holes and supports are optional elements. The hot water, heated by the silicon-encased heating element106on the bottom of the container112, will rise and the cooler water from above will fall, creating a continual convection current flow in the water bath resulting in relatively constant temperature throughout the water bath. The holes402in the heating element106are not necessary for convection circulation to occur, but are helpful if not at times necessary to help get the heating element onto the bottom of a container112full of water. It is a lot easier to put a strainer down in a pot of water than it is to lower a solid bottomed item. With the holes402in the heating element106, there is much less resistance from the water in the container112during lowering, because the water will go through the holes as the heating element is inserted into the water bath. The shape of the heating element106is discussed further inFIG.14andFIG.15.

FIG.1Cis a schematic of a top view of the sous vide sous vide cooking appliance100in an uncovered container112. The control unit102is shown sitting on top of the edge of the stock pot. The control panel110is shown on the top side of the control unit housing. A clip assists the control unit housing to sit atop of the lip of the container112. The heating element106is shown at the bottom of the container112. Various types of heating elements106may be used with this embodiment. Side handles are shown for the container112. A power cord114extends from the control unit housing to be plugged into an electrical outlet or extension cord. The sous vide cooking appliance100may be operated at various voltages and amperages to accommodate international electrical standards.

In many embodiments, the sous vide cooking appliance100uses a PID controller versus other temperature controllers. A PID controller versus other type of temperature controllers reduces overshoot as the temperature is rising to the set temperature, as well as undershoot. A PID controller assists in maintaining the temperature to within a half degree or so over the many hours that sous vide cooking sometimes requires.

While some appliance embodiments use multiple temperature sensors, one temperature sensor108is sufficient. In single sensor embodiments, whether using a flexible conduit104(or flexible wire set up) or a solid conduit, locating the temperature sensor108at roughly the midway point between the bottom of the pan (or the top surface of the heating element106) and the surface of the water is helpful with accuracy. Additional temperature adjustments may be used when the temperature sensor108is located at a height that is far from the midway point.

In some embodiments, sensors are used to determine whether the level of water is below a threshold or desired level. Temperature sensors108or other sensors may be used for this purpose. The sensors sense the lack of water present or a sense a temperature or temperature differential indicating no water at the temperature sensor108. An alarm or other notification is provided by the control unit if the water level is low.

In embodiments in which the conduit104is a solid structure, hinging the heating element106from the solid conduit may be desirable. The hinged heating element106may be folded up and towards the solid conduit carrying the wires to the heating element at the bottom of the appliance. Folding makes storage and transportation of the sous vide cooking appliance100easier.

In some embodiments, the heating element106is configured to lay at the bottom of the pot or cooking basin. To accommodate this positioning of the heating element106with different height pots and containers, the solid conduit's length is configured to adjust. In one embodiment, the conduit104includes a telescopic length adjustment. In this manner, it is possible to have the heating element106on the bottom of the container112regardless of the height of the container. The conduit104telescopes by three or four inches, for example, to accommodate most pots and plastic basins. For greater flexibility, the conduit104can be configured for adjustments of vertical height (for example adjustments of 1 to 2 inches, 2 to 5 inches, 2 to 7 inches, 3 to 10 inches, or greater) such that the conduit with adjustments is able to accommodate pots of a few inches tall to 24 inches tall or greater.

In some soft-conduit or flexible conduit configurations, a slightly weighted heating element106is used with a connection to the control unit housing by a flexible wire. In these embodiments, the resilience of the flexible wire must be adequate, as wires tend to break when they are bent, straightened, and re-bent repeatedly. The wrapping of the electric wire for its full length to the heating element106must be watertight. Also, in these flexible embodiments the temperature sensor(s)108are placed along the electric wire either inside or outside of a protective wrapping. Temperature adjustment algorithms are simplified when the single temperature sensor108is about halfway between the bottom of the water and the top or if multiple temperature sensors are spaced apart in height. The soft or flexible conduit configurations make the sous vide cooking appliance100even more compact and easy to store or transport.

FIG.2Ashows a cut-away side view of a container112, e.g., a stock pot, with a sous vide cooking appliance100mounted on the side of the pot and using a flexible conduit104or wire. The sous vide cooking appliance100includes a control unit110with a control unit housing enclosing electronics, a bracket202, a power cord114, a flexible conduit104, a temperature sensor108mounted to the flexible conduit approximately midway, and a heating element106with supports204connected to the flexible conduit140. In this embodiment, the control unit102housing hangs from the side of the container112on a “C” clip or bracket202. In this configuration, the container lid206may be closed, nearly closed or partially closed onto the top of the container112. A soft-conduit or flexible conduit104is used to bring electric power from the control unit102housing to the heating element106. The conduit104crosses over the lip of the container112and down inside the container. The container lid206may close on the “C” clip bracket202or on the conduit104or both. A heating element106with supports204is sitting on the bottom of the container112.

FIG.2Bshows a side view of an embodiment of a sous vide cooking appliance100with a soft or flexible conduit104and two hanging clips holding the control unit housing over the side of a container112. In this view, the control panel110can be seen pointing outward from the side of the container112. A container lid206is shown being placed atop the container112. A power cord114is also shown extending from the control unit102housing to be plugged into an electrical source.

As shown inFIGS.2and3, in soft or flexible conduit embodiments, the control unit102, in particular, the housing for the control unit, can be located outside the container112and out of the way of the container lid206. In one embodiment, the control unit102hangs from the top lip of the container112(using one or two clips202) along the outside of the container. In this embodiment, the control panel110or controls on the control unit102face out from the side of the container112. With this embodiment, users may use the container lid206to cover the container112during sous vide cooking. The thickness of the clips202for hooking the control unit102to the lip of the container112and the thickness of the flexible wire conduit104can be kept to a minimum to allow the container's lid206to close as much as possible. Closing the container's lid206eliminates the need for wrapping tin-foil over the top of the pot, or placing floating ping pong balls in the pot, or doing any of the other things users have to do with immersion circulators to minimize water loss from water evaporation out of the pot. The clips202and flexible or wrapped wire conduit104can be configured to block steam flow from gaps formed between the container lid206, container112, clips202and conduit104. Rubber, silicone, plastic or other materials may be used to minimize the gap or gaps formed when the sous vide cooking appliance control unit102hangs over the side of the container112. The additional material or gap filler can smooth out the bumps or lift created by the clips202and conduit104and allow the lid to uniformly make contact the gap filler.

Referring toFIG.2B, in soft conduit embodiments, the soft conduit104length may also be adjustable. In addition to the components shown inFIG.2A, the embodiment ofFIG.2Bincludes a retractable reel conduit unit208having a magnet210and temperature sensor108attached. In one embodiment, a retractable reel conduit unit208is used in the water to adjust the length of a flexible conduit104. For example, as shown inFIG.2B, the sous vide sous vide cooking appliance100includes a retractable reel conduit unit208positioned about half way between the container lid206and the heating element106. This retractable reel conduit unit208may also include the temperature sensor108mounted on the inside or outside of the reel housing. This retractable reel conduit unit208may extend the soft conduit104length in one direction (between retractable reel conduit unit208and control unit102) or the other direction (between retractable reel conduit unit208and heating element106) or both (bi-directional). In some embodiments, the retractable reel conduit unit208spools the excess flexible wire.

FIG.2Bshows a retractable reel conduit unit208that is bi-directional and includes two spools212. One or two spools212may be used to gather the excess conduit104wire. As shown inFIG.2B, the retractable reel conduit unit208may also include a magnet210to help the retractable reel conduit unit208adhere to the side of a metal container112. While the magnet210is shown mounted to the outside of the retractable reel conduit unit208housing, it may be located within the housing. In other embodiments, the retractable reel conduit unit208is located near or closer to the control unit110and in yet other embodiments, the retractable reel conduit unit208is located near the heating element106.

In some embodiments, a temperature sensor108is mounted to the outside of the retractable reel conduit unit208as shown inFIG.2B. Alternatively, the temperature sensor may be mounted inside the retractable reel conduit unit208housing. In some embodiments in which the temperature sensor108is on the inside of the conduit104or inside of a retractable reel conduit unit208, sealed from contact with water in the water basin, a temperature adjustment is used. In other words, if the temperature sensor108is inside a hard or soft conduit104and does not make contact with the water, a temperature adjustment is available to determine the actual water temperature from the proxy temperature measured in the sealed environment by the temperature sensor. In these embodiments, the PID controller includes a temperature adjustment algorithm which adapts the temperature sensor108readings from inside of the conduit104or inside the retractable reel conduit unit208to actual water temperature. The indirect temperature reading of the temperature sensor108is adjusted to reflect the actual temperature of the water. In some embodiments with sealed temperature sensors108, the conduits104are made from materials which will conduct heat such as stainless steel, other metals or other materials with good heat conductive properties.

FIG.3shows that, in some configurations, the control unit110can hang down from the lip of the pot over the side of a container112on hooks302or the like. In one embodiment, the control unit102is hung well over the side of the container112away from the container lid206. When using a container lid206on the container112or other cooking vessel, the opening caused by the hooks302to hang the control unit102, direct the steam in the direction of the control unit. By hanging the control unit102below the level of the top of the pot, the steam will rise and not directly hit the control unit. With the control unit102hanging off the side of the container112, a soft conduit104configuration is preferred with the conduit104traveling over the side of the container112and down to the heating element106.

FIG.4shows an additional embodiment in which the control unit102and control panel110are in a separate housing outside of the container112and connected by a wired conduit104. In this embodiment, the wired conduit104may be flexible and connect the heating element106to the control unit102with the control panel110, which may lie on a surface external to the container112, such as a counter top. This system has an advantage that the electronics are away from the water and heat source, there are no moving parts, and it is easy to clean. In some embodiments, the control unit102has a flat rubber bottom for securing it to a counter. In other embodiments, the control unit102has supports204beneath the base for air flow. The electronics are located with the control unit102. A battery back-up power may be included.

In one embodiment, the conduit is a flat cable for a lower profile throughout or at the point where the cable exits the pot to minimize the gap between the container lid206and the container112. A lid may be used with a cut-out for the flat cable. In another embodiment, the supports204may be weighted to keep the heating element106and cable submerged. A number of supports204of varying type may be used.

In one implementation, there are two temperature sensors108on the wire leading to the heating element106, one near the heating element, and one a few inches up, for example. The temperature sensor108by the heating element106informs the control unit102if the container112has water in it when it is turned on. This can be accomplished by sensing whether liquid is present or sensing the temperature to determine the presence of a liquid.

In another implementation, the control unit102has a safety feature which automatically turns off the machine if the temperature near the heating element changes outside of the norm, too high or too low. For example, if the temperature goes up too quickly, which is a sign that there is no water in the pot or the system is overheating, the safety feature will turn the system off. If the temperature remains unusually low for an extended period of time, it could signify a fault in the system requiring shut-down. In some embodiments, the control panel will stay on but power to the heater is turned-off for safety reasons. Once the container112has water and is heating normally, the control unit102reads the temperature from the temperature sensor108several inches up from the bottom, which is the temperature about at mid-depth of the water and reflects the temperature throughout the water as the convection currents keep it moving. The control unit102may also get feedback from the lower temperature sensor108, but that will typically be a little warmer since it is almost right on the heating element. Additional temperature sensors may be used at other locations along the line or in the system. In some embodiments, the system averages the temperatures between sensors. In other embodiments, temperature correction calculations are used and in yet other embodiments, temperature conversion factors are used for one or more of the temperature sensor readings.

Additionally, given that different-sized heating elements106may be used, the control unit may also regulate the power provided to the heating element106based on its size. Generally, larger heating elements106are provided more power. In some embodiments, the heating elements106are exchanged by plugging or unplugging them into the system100.

In one implementation, the control unit102may be connected to more than one heating element106at a time. For example, the control unit102may control a heating element106in one pot cooking one type of food, while controlling another heating element in another pot cooking a different type of food. The control unit102is used to set the water temperature and different water temperatures may be programmed for each heating element106. Also, different timers may be set for each heating element106depending upon the cooking time required for each food.

FIG.5illustrates the heating element106of the embodiment ofFIG.4, in which the control unit is housed separately. As shown, the sous vide cooking appliance100may have two temperature sensors108, one centered on bottom of the pad, and one up the side wall of the container112at the base of the conduit104near the heating element106. In one implementation, this may be 2.25 inches up the side wall of the pot, for example. Additional heating elements106may be placed on the conduit104.

The heating element106may also be foldable for ease of storage. There may be a hinge at the base where the conduit104connects with the heating element106. Examples of hinges are described earlier.

FIG.6illustrates the back of the control unit102of the embodiment ofFIG.4, in which the control unit is housed separately but connected by a flexible conduit104. As shown, there may be a single plug for simplicity of device setup at the user's end, such that the plug from the conduit104and the power cord114are connected and plug into the back of the control unit102. In other embodiments, there are two plugs.

FIGS.7and8show external view of a container112, control unit102, power cord114and conduit104of the embodiment shown inFIG.4from in front and behind the control unit102.

FIGS.9and10show see-through views of a container112, control unit102, power cord114, conduit104of the embodiment shown inFIG.4from in front and behind the control unit102. In this view, the heating element106may be seen in the container112

FIGS.11and12show alternative embodiments of heating elements106. In particular,FIG.14shows a heating element106with holes402andFIG.15shows a heating element106generally in the shape of a grating. Various materials may be used to form the heating element106. These heating elements106are adapted to be submerged into the water basin of a pot or other container112. Silicone encasing, rubber encasing or other water tight casing may be used to protect the heating element106from the water. A connection1202must be made between the heating element106and the conduit104wire carrying electric power to the heating element. In various embodiments, the connection1202is durable and has some flexibility. Silicone, rubber or other material may be used to encase the connection1202and provide it protection from pulling apart.

FIG.13illustrates a flowchart1600of a method in accordance to one embodiment. The control unit102activates the heating element106in a separate container112containing a liquid for sous vide cooking without a motor for circulating water (step1602). The temperature sensor108detects a temperature of the liquid in the separate container112(step1604). The control unit102determines whether to deactivate and activate the heating element106based on the temperature of the liquid (step1606). The deactivates and activates the heating element by the control unit based on the determination (step1608). In one implementation, the control unit102may keep the temperature of the liquid within a 1 degree range, for example, by controlling the heating element106, for sous vide cooking. Other ranges may be also be used.

To begin, a user may put the heating element106in a separate container112, and turn on the control unit102using the control panel110. The user may also disconnect the heating element106from the control unit102, and connect a different heating element of a different size than the original heating element to the control unit. Additionally, a second heating element may be connected to the control unit102, and be used in a different container112at the same time as the original heating element106.

A seller of the sous vide cooking appliance100can provide one or more of the system elements described. For example, a seller may provide a consumer the control unit102, power cord114, conduit104, temperature sensors and one or more hinged or unhinged heating elements106. In distributed sous vide appliances100in which multiple heating elements106are provided, they may be of different sizes.

In alternative embodiments, the control unit102electronics are solely battery powered and in yet other embodiments run on battery or electricity interchangeably. In some embodiments, the batteries are stored with the control unit102housing, in others it is external to the housing. Battery power or battery back-up power for the control unit provides safety against power outages by arming the user with valuable information about the food being cooked, for example, when the power went out, how long the power was out, and for how long at what temperature the food was left to cool off. Knowing the coldest temperature the food was subjected to in the water bath is useful information. Also, knowing the length of time that the food was exposed to reduced temperature is useful to calculate risk of spoilage. For food safety, this type of knowledge is helpful in order to determine whether the food must be discarded or can be cooked, reheated and/or eaten. Various methods may be used to determine risk of spoilage using on information on temperature and time. In one embodiment, the entire sous vide cooking appliance100, including the heating element106, is solely on battery power or has an available battery back-up. The cordless or battery only configuration allows for remote operation of the cooking appliance100without an electric wall outlet. The battery back-up configuration can accommodate power outages. In one embodiment, the battery unit is a self-standing device remaining on the counter and not attached to the pot or water container112.

The sous-vide cooker appliance100is described as being used with water. However, other fluids may be used in the bath.

In one embodiment, the electric wire is housed in a water tight conduit connecting the control unit housing to the heating element.

In another embodiment, the conduit length is adjustable from 1 to 12 inches, or adjustable from 4 to 20 inches.

In yet another embodiment, there is a flexible waterproof cover connecting the control unit to the heating element, and the electric wire is located within the flexible cover. Furthermore, the conduit may include a flexible covering for the electric wire leading to the heating element that is water tight.

The heating element may further comprise slots for water to pass through, or a grating, and the grating may have equally spaced apart parallel heating components. The heating element may be a circular grating with equally spaced apart parallel heating components arranged longitudinally and latitudinally in a two-dimensional grid.

The sous vide cooking appliance100may also comprise two or three temperature sensors spaced apart in height. The one or more temperature sensors may also be attached to the outside of the conduit.

The foregoing description of various embodiments provides illustration and description, but is not intended to be exhaustive or to limit the invention to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice. It is to be understood that the invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the claims.