HK1201035B - Cooking assembly and processing method for cooking - Google Patents

Abstract

Food stuffs are cooked at precise temperatures, which are optionally below 100 ºC, in a vessel that is evacuated to exclude air, in which low pressure steam replaces the air. When a sufficient quantity of air is excluded and replaced with water vapor, the temperature of vapor is accurately measured inside the vessel below the lid to control the temperatures within about 1º C. Air is preferably excluded via a controlled heated process for a relatively short period of time at high temperature to generate steam, the temperature is lowered to condense water vapor upon which the lid will sealingly engage the rim of the vessel, forming a partial vacuum in the cooking vessel.

Description

Cooking assembly and processing method for cooking

Technical Field

The present invention relates to a method of cooking food products, and in particular to cooking food under controlled temperature conditions and a suitable cookware vessel and apparatus for use in the method.

Background

Existing methods of controlling cooking include the so-called Sous Vide method, in which the foodstuff is sealed in a plastic bag, and the sealed bag is then placed in a temperature controlled water bath (water bath). The temperature of the water bath of the food to be cooked is specific and in the case of animal proteins is sufficient to denature some of the proteins and also to dissolve collagen, depending on the nature of the animal proteins, and/or to influence other chemical transformations of the ingredients of the food material at a precise level. However, since the temperature of the food product inside does not exceed the temperature of the sink, the cooking time must be sufficient for the inside of the food to reach this temperature. Cooks use guidelines or experience to determine cooking time and often to determine a desired cooking temperature. Alternatively, a needle-shaped temperature probe may be inserted into the plastic bag through the foam seal to actually measure the internal temperature of the food product during cooking and thus terminate cooking when the entirety of the food has reached the desired temperature. This termination is preferred in the case of fish and other proteins which degrade severely when held at this temperature in excess, compared to other protein sources such as split meats which are generally considered inferior (generally harder due to high collagen content). In these cases, the cooking time is extended by several hours (even if not several days) to at least partially dissolve a large percentage of the collagen to tenderize the meat.

While the use of plastic bags to preserve food material is helpful for the seasoning of some food products and for the subsequent cooling and freezing of cooked food within the plastic bags, it adds expense and complexity to the average consumer. In particular, it should be noted that this is difficult for vacuum-sealed bags containing fluids unless very expensive equipment is used, and that these processes are time-consuming. The vacuum sealing process increases the preparation time of the food relative to other cooking methods, despite the fact that the cook can do other things in the kitchen throughout the cooking period due to the constant temperature of the sink (which largely prevents over-cooking of many types of food).

However, these sinks with precise temperature control are expensive, consume a large amount of counter space and in many cases also constantly flood the kitchen with water vapor. In addition, filling and heating the water bath also delays the cooking time.

Another method of cooking food at low temperatures, i.e., below the atmospheric boiling point of water (100 ℃ or 212 ° F), is performed in a reduced pressure chamber. One such method of heating a microwave transparent container having a lid in a microwave oven is disclosed in U.S. patent application No.2003/0038131a 1. The container lid has a gasket to seal the container and a central one-way valve to release steam. The foodstuffs are heated by microwaves so that they release moisture, which together with the added water is converted into steam at high microwave power. Since the one-way valve is designed to limit the return of air when the steam condenses into water, a vacuum is created in the container. Although a relatively short initial heating cycle can be used to evacuate the air and expanded steam, the food material has already been cooked to some extent by the initial microwave radiation, and therefore, for delicate or thin food materials, the benefits of low temperature cooking are still not obtained. The application also fails to teach or disclose how to maintain a subsequent temperature or pressure within the container.

U.S. patent nos. 5,318,792, 5,767,487, 5,662,959 and 6,152,024 disclose various oven (oven) configurations for cooking in a low pressure steam environment. The oven is sealed with a gasket and is in fluid communication with an external vacuum pump. The food material is held above an internally heated water tank. Similar to the Sous Vide cooking, the sink temperature is measured so that under equilibrium conditions the food product will be exposed to water vapor at the same temperature of the ambient. The devices disclosed in these patents are for commercial use, but also have inherent limitations for consumer use. These ovens are large, bulky, and prone to malfunction due to exposure of moving parts and heaters to water or water vapor.

Us patent No.4,381,438 discloses a cooking device configured with an induction heating base to heat a cookware vessel. Controlling power to inductively heat the cooking base in response to a sensor located in the lid of the container. The sensor detects the steam and reduces the heating power in response to the steam or the temperature of the steam. This disclosure fails to provide an indication of the accuracy of the method and the stability of the temperature within the container.

Disclosure of Invention

It is therefore a general object of the present invention to overcome the above drawbacks of the Sous Vide cooking, in particular to eliminate the vacuum-sealed plastic bag, using a cookware vessel that is also suitable for general use.

It is also an object of the present invention to provide a cooking apparatus and method that enables cooking of a variety of large, thick and/or irregularly shaped foods that a cook should not seal in a vacuum plastic bag for Sous Vide cooking, as these foods will have extremely long cooking times and may cause food safety problems.

It is also an object of the present invention to provide a method of cooking these large sized, thicker and/or irregularly shaped foods without sealing in a vacuum bag at low temperatures below the boiling point of water, which has an accelerated pattern compared to the longer time required for Sous Vide cooking.

It is another object of the present invention to provide these benefits and advantages in a cooking method that can use either the common heating source in the consumer's kitchen, or at least a specific heating source that is compatible with other cooking methods.

In the present invention, the first object is achieved by providing a cooking assembly comprising: an induction heating base having an upper surface for supporting a cookware vessel; one or more induction heating coils disposed below the upper surface; a controller responsive to energize the one or more induction heating coils; a cookware vessel having a base adapted to be supported by the upper surface of the induction heating base, a substantially upright sidewall extending upwardly from the base and terminating in a rim, the sidewall forming a fluid-retainable interior surrounding the base; a lid having a gasket to engage with the cookware vessel at the rim of the vessel to form a vacuum seal, the lid having at least one sealable perforation formed in a surface thereof; an emitter device adapted for removable supportive engagement with the lid and in signal communication with the controller, the emitter device having a heat probe that enters an interior of the container via the sealable perforation of the lid, wherein the controller is operable to energize or de-energize the one or more induction coils in response to a temperature measured by the heat probe to maintain a predetermined temperature input to the controller, wherein the gasket and the sealable perforation in the lid are adapted to maintain at least one of a partial vacuum and a pressure greater than atmospheric pressure in the interior of the container, wherein the cooking assembly comprises means to reduce the partial pressure of air within the cookware container to 0.3 bar and less.

A second aspect of the invention features the cookware assembly wherein the means to reduce the local pressure of the air within the cookware vessel to 0.3 bar and less is the controller that first energizes the induction coil at least until the thermal probe detects a temperature of about 200 ° F.

Yet another aspect of the invention features the cooking assembly wherein the controller is operable to de-energize the induction coil a calculated time after receiving a signal from the transmitter to reach a first predetermined temperature, wherein the time to reach the first temperature is used to determine the calculated time.

Yet another aspect of the invention features the cooking assembly, wherein the calculated time is sufficient to provide for generation of an amount of water vapor operable to vent air from the container such that a vacuum seal is formed between the lid and the rim via the gasket after the calculated time de-energizes the induction coil.

Yet another aspect of the invention features the cooking assembly wherein the calculated time is sufficient to provide generation of an amount of water vapor operable to expel air from the container, the calculated time being a time to reach at least about 94 degrees minus 60 seconds and then divided by 2.

Yet another aspect of the invention features the cooking assembly wherein the transmitter is wireless and includes a processor that calculates a time of transmission based on a change in temperature over time.

Yet another aspect of the invention features the cooking assembly wherein the lid further includes an annular handle surrounding a sealable perforation in the lid and the transmitter is adapted to nest within an inner ring of the annular handle, wherein the heat probe penetrates and seals the sealable perforation via a removable grommet.

Yet another aspect of the invention features a cooking assembly, including: a cookware vessel having a base, a substantially upright sidewall extending upwardly from the base and terminating in a rim, the sidewall forming a fluid-retainable interior surrounding the base; a sealing device that creates a vacuum within the container; heating means for providing thermal communication with the cookware vessel; a controller that regulates an output of the heating device; a thermal probe adapted to measure a temperature of at least a portion of the container or its environment; an emitter device adapted to receive the output of the thermal probe and to send a value to the controller, wherein the controller is operable to energise or de-energise one or more induction coils to maintain a predetermined temperature input to the controller in response to the temperature measured by the emitter device, wherein the cooking assembly comprises means to reduce the partial pressure of air within a vacuum sealed container to 0.3 bar and less.

Yet another aspect of the invention features the cooking assembly, wherein the sealing device is a gasket and a lid, and the gasket is adapted to engage a portion of the rim of the container.

Yet another aspect of the invention features the cooking assembly including a sealable perforation in the lid that is closed by a heat probe portion of the transmitter extending into the container interior.

Yet another aspect of the invention features the cooking assembly wherein the gasket and the sealable perforations in the lid are operable to maintain at least a partial vacuum and a pressure greater than atmospheric pressure in the interior of the container.

Yet another aspect of the invention features the cooking assembly wherein the gasket is operable to be pushed downwardly by the lid when the container is evacuated such that its visible portion above the container rim is disposed below the container rim after evacuation.

Yet another aspect of the invention features the cooking assembly wherein the gasket has an F-shape and a sidewall portion of the container below the rim has a curvilinear portion that contacts portions of the F-shaped gasket when a vacuum is formed within the interior of the container.

Yet another aspect of the invention features a process for cooking, the process including the steps of: providing a container capable of holding a fluid, the container having a lid in sealable engagement with the container rim; introducing at least one of water and an aqueous fluid into the container; placing food material in the container; placing the lid on the container; heating the vessel to a first temperature at least until water is converted to a sufficient amount of water vapor to replace the atmospheric content of the vessel; reducing the heating power to the container to bring the container to a second temperature lower than the first temperature, wherein condensation of water vapor within the container causes a reduction in internal pressure sufficient to engage the lid to seal with the rim of the container; and maintaining the container at the second temperature for a predetermined amount of time.

Yet another aspect of the invention features the process described above, wherein the step of heating to a first temperature is from a radiant heat source below the vessel.

Yet another aspect of the invention features the process described above, wherein the radiant heat source is an induction cooking base.

Yet another aspect of the invention features the process described above, wherein the lid further includes a means for measuring the temperature in the container, and the step of maintaining the container at the second temperature further includes the steps of: the induction cooking base applies a series of spaced apart power pulses, wherein the temperature rise caused by each pulse is measured by the means for measuring temperature, and the power of each subsequent pulse is determined from the measured change from the first temperature.

Yet another aspect of the invention features the process described above wherein the lid further includes means for measuring the temperature in the container and the step of heating the container to a first temperature is terminated at a time calculated from the first time that the predetermined temperature is reached at least until the water is converted to a sufficient amount of water vapor to replace atmospheric content within the container.

Yet another aspect of the invention features the process described above, wherein the predetermined temperature is at least about 94 degrees, and the time to terminate heating to the first temperature is the first temperature minus 60 seconds and then divided by 2.

Drawings

The above and other objects, effects, features and advantages of the present invention will become more apparent from the following description of the embodiments of the present invention taken in conjunction with the accompanying drawings.

Fig. 1 is a cross-sectional view of an induction oven heated cooking vessel arrangement suitable for low pressure steam cooking, wherein the lid includes means to measure the temperature of the vessel contents and communicate with the induction oven for precise temperature control.

Fig. 2 is a flow chart showing steps of a cooking process using the container and lid sensor shown in fig. 1.

FIG. 3 is a block diagram of a thermal control system for the apparatus of FIG. 1.

Fig. 4 is a schematic diagram of the temporal variation of temperature and pressure in the vessel of fig. 1 resulting from operation according to the first mode of the flow chart of fig. 2.

Fig. 5 is a schematic diagram illustrating the application of power during time T3 in the control zone portion of fig. 3 to achieve a consistent cooking temperature T3.

Fig. 6A is a cross-sectional view of an alternative cooking vessel with a preferred lid gasket, while fig. 6B is an enlarged cross-sectional view of a portion of the gasket and lid of fig. 6A.

Fig. 7A-7C compare the temperature change within the container of fig. 6A at different levels of replacement of air with water vapor during the transition from the first control temperature at 158 ° F to the control at 140 ° F.

Fig. 8A and 8B compare the temperature change corresponding to the process according to fig. 1-4 with and without air replacement to maintain a steady state temperature of 120F.

Fig. 9A to 9D compare the temperature change according to the process of fig. 4 when maintained at a range of steady state temperatures at 0.08 bar.

Fig. 10A to 10C are sectional views of a part of a gasket and a container cover.

Fig. 11A is a cross-sectional view of the corresponding portions of the gasket and cap disposed on the rim of the container in the discharge state, while fig. 11B illustrates the distortion of the gasket and the lowering of the cap toward the container in the evacuated state.

12A-12D illustrate a preferred embodiment of a lid handle 215 having an eyelet 170 for sealing engagement with a thermal sensor, wherein FIG. 12A is an exterior elevation view of the eyelet and FIG. 12B is a cross-sectional view of the grommet of FIG. 12A; fig. 12C is a bottom view of the grommet, and fig. 12D is a cross-sectional view of an alternative handle assembly showing the grommet and the temperature sensing device disposed within the handle.

FIG. 13 is a cross-sectional view of the lid handle of FIG. 12 wherein the thermal sensor and gasket are replaced by a valve that operates to communicate with the container and release the vacuum formed therein.

FIG. 14A is a cross-sectional view of the valve of FIG. 13, FIG. 14B being orthogonal to the cross-sectional view to show the wider portions of the valve stem and valve base, and FIG. 14C being an exterior elevational view of the valve in the same orientation corresponding to FIG. 14A; FIG. 14D is a cross-sectional view of the ring securing the handle to the cover; fig. 14E is a sectional view of a handle, and fig. 14F is a corresponding scale sectional view of an assembled handle, ring and valve attached to an adjoining cover portion of the valve in a closed position.

Fig. 15A is a perspective exterior assembly view of the handle of fig. 13 and 14A-14F prior to attachment to the lid, fig. 15B is a perspective exterior view of the handle of fig. 12 and 13 with the valve closed, and fig. 15C shows a perspective view of the valve open position.

Fig. 16A is a cross-sectional view of another embodiment of a cooking apparatus suitable for low temperature steam cooking and cooking under elevated pressure with steam hotter than 100 ℃ (212 ° F), while fig. 16B is a cross-sectional view of an alternative thermal sensor and vacuum forming device.

Fig. 17 is a cross-sectional view of another embodiment of a cooking apparatus suitable for low temperature steam cooking of a container containing raw food or food to be heated in another vacuum container.

Fig. 18 is a cross-sectional view of another embodiment of a cooking apparatus suitable for low temperature steam cooking heated by an ambient temperature controlled oven.

FIG. 19 is a timing diagram of signal transmission of two different thermal sensors each associated with a different container to control a heat source associated with the container and in proximity to each other.

Fig. 20 is a schematic illustration of the time variation of the temperature in the vessel of fig. 1 or 6 resulting from another mode of operation according to the flow chart of fig. 2.

Detailed Description

Referring to fig. 1 through 20, wherein like reference numerals refer to like components in the various views, there is shown a new and improved cookware vessel assembly for low pressure steam cooking, generally designated 1000 herein.

The method and apparatus disclosed below enable cooking of a variety of foods at optimal temperatures and stages of different temperatures, and in a more preferred embodiment enables exceptionally precise control of temperatures to achieve a consistent degree of cooking integrity for a wide variety of food products.

These results are achieved by finding a particular temperature uniformity that can be achieved when the container is sealed with a very low partial pressure of air, which is replaced with water vapour in a stable equilibrium. This result is most preferably achieved in the configuration of fig. 1 where the container is heated from below. The cooking temperature may be well below the boiling point of water at atmospheric pressure (212 ° f (100 ℃)).

Commercially available cooking facilities cook food at temperatures below 212 ° F by sealing the food in a vacuum bag placed in a thermostatic bath. The vacuum bag is maintained in the sink for a time sufficient to bring the center of the food to the sink temperature. This cooking method is commonly referred to as Sous Vide cooking, which is translated from french-in vacuo-Sous Vide cooking, which, although commonly used in commercial kitchens, is not so in ordinary consumer use.

According to the present invention, it should be understood first that low-pressure steam cooking is a process that does not require the food material to be sealed in a plastic bag before cooking, since the food material is immersed in a temperature-controlled low-pressure steam environment. Since the steam does not remove the food's aroma components and vitamins, there is no need to seal the food and plastic bags or other containers, although such sealing can be done when it is desired to provide the aroma components from a liquid or aqueous medium, such as liquid fatty oil or olive oil, or from a boiling liquid, such as sauce.

It has been found that with the apparatus of the present invention all the advantages of Sous Vide cooking can be obtained without the limitations associated with Sous Vide cooking. These limitations include cooking only a small amount of food material that is relatively small and flat, extended cooking times, and unnecessary extraction of liquid from the animal protein into the surroundings of the evacuated plastic bag, among others. Thus, the following disclosure will explain how to overcome these disadvantages using the apparatus and process of the present invention.

Fig. 1 illustrates a preferred embodiment of a cooking device 1000 suitable for the cooking method of the present invention, the cooking device 1000 comprising a container 110 capable of containing a liquid, the container 110 having a rim 113 at the terminating upper edge of a sidewall 112 surrounding a sealed bottom 115. The vessel 110 is disposed on a horizontal heating source 400, the heating source 400 preferably being flat or abutting at least a portion of the exterior bottom of the vessel 110. The lid 200 is adapted to be substantially vacuum tightly engaged with the rim 113 of the container via a gasket 250 that engages and co-seals with the perimeter 214 of the lid 200. The lid 200 provides at least one container vent 111. The temperature measuring device 300 is preferably provided in the cover 200, but may be disposed at an alternative position. The temperature measurement is used to control the output of the heater 400 for a desired combination of power, time, and temperature to achieve the benefits and advantages summarized above, as discussed in more detail below.

It has been found that because of the excellent circulation of the low pressure steam within the vessel, cooking temperatures can be accurately monitored and controlled using a heat probe 322 that descends only a few millimeters into the interior of the vessel 110 via the inlet of the lid 200, as shown in fig. 4-6. In other words, such thermal sensor probes constantly monitor the ambient steam temperature. Since its accuracy will depend on the efficiency of heat transfer between the probe and its surroundings to quickly reach thermal equilibrium, the thermal sensor probe works optimally in a partial vacuum pan when surrounded by saturated low pressure steam after most of the air is expelled out of the pan. The same inlet 205 into which the thermal probe 322 is inserted is the preferred vacuum exhaust.

The preferred method of forming low pressure steam is to replace the air by heating or boiling a very small amount of water, it has been found that a vacuum sufficient for low pressure steam cooking can be obtained without a separate pressure measurement or a separate air pump.

It has also been found that sufficient time for such boiling can be obtained based on the time it takes to heat the water so that the heat probe is close to the boiling point of the water. The time required to form low pressure steam for cooking is approximately 50% of the heating time required to bring the measured steam temperature from room temperature to 94 ℃ (201 ° F) minus 60 seconds. Time t2 is preferably calculated by subtracting 60 seconds from t1 and then dividing the result by 2.

Thus, in a more preferred embodiment of the invention, the heat probe measurements are submitted to the controller 430, which records the time required to reach 94 ℃ (t 1). If the heating time is less than 60 seconds, the heat source 460, preferably an induction furnace, will immediately stop heating.

This control scheme works under a range of conditions including variations in pot size from 16 cm to 24 cm diameter, using both stainless steel and aluminum cookware bodies, and starting with about 30 ml to about 200 ml of additional water in the vessel, regardless of food content. The lack of food content has been successfully simulated by evaluating the control method with 200 ml of ice sealed in the bag. In all cases, further cooling to 30 ℃ ambient temperature achieved a vacuum level of at least about 0.3 bar.

Under these conditions, when the water vapor temperature drops below 95 ℃, a sufficient vacuum is achieved to seal the lid 200 to the rim 113 under its weight via the gasket 250. Thus, low temperature steam cooking can be satisfactorily performed for cooking temperatures up to 190 ° F (about 87 ℃) without having to be lowered to the desired cooking temperature before reheating occurs. In the method of the invention, boiling takes place in 60-300 seconds, depending on the size of the pot and the water/food content, using various 3-4 litre vessels with attached induction cooker base and commercially available induction stoves. Subsequent cooling, lacking heating for 240-1500 seconds, while dependent to some extent on container dimensions and water/food content, enables the water vapor temperature to be reduced to a desired cooking temperature in the temperature range as low as 50 ℃. Thereafter, subsequent heating to the higher cooking temperature takes only about 30-90 seconds.

Accordingly, a further aspect of the invention includes the following processes: the steam temperature is cooked and maintained for at least about 1 ° F (1.8 ℃), more preferably, a desired cooking temperature of 1 ℃.

In the preferred embodiment of fig. 1, the temperature measuring device 300 is provided with a heat probe 322, the heat probe 322 being lowered downwardly through the sealed perforation 205 in the lid 200 to measure the temperature of the interior of the container 110 and the interior of the lid 200 near the rim 113. This original seal penetration 205 is optionally a container vent when the thermal probe 300 is disengaged from the cap 200. As shown in fig. 5, 11 and 15, the temperature measuring device 300 is also preferably a movable handle or assembly nested in a recess in a ring-shaped or handle-like handle 215 for gripping and lifting the lid 200. It is also preferred that the container lid 200 be dome-shaped to provide strength, and more preferably folded about its lower edge to increase the rigidity of the gasket engagement or receiving portion.

Alternatively, the temperature measurement device 300 is optionally an external thermal sensor in thermal communication with the container interior via the sidewall rather than the lid. The internal temperature measuring device 120 is a thermal probe such as a thermocouple, a thermistor, a thermopile, an infrared temperature detector, and the like. The temperature measuring means may also be a thermal probe attached to the side wall of the container, more preferably a thermal probe arranged in thermal communication with the inner wall of the double-walled container, wherein external signal communication from the thermal probe may optionally be through wires extending through or connected to the outer side wall. Alternatively, the container 110 may be equipped with signal feed-throughs for thermal probes (such as thermocouples or thermistors inserted directly into the food product 1).

It should also be understood that the temperature control device optionally resides in the thermal probe, heating device, or other device, and in addition to the preferred control scheme disclosed below, is optionally a proportional-integral, derivative controller (PID) in signal communication with the controller of the output of the heating device. Furthermore, the heating means is preferably an induction furnace base, but may alternatively be an infrared heating base, a heated metal plate, a ring or coil or a gas flame. Alternatively, the heating device may be an oven, as shown in fig. 17. In fig. 18, since the heated interior of the oven surrounds the container 110, the container and its interior will eventually reach the oven temperature of the oven. Heating devices or sources having thermal mass, such as heating rings and hot plates, are less preferred because it is more difficult to precisely control the temperature disclosed in the preferred embodiment.

As shown in the block diagram of fig. 3, the preferred thermal measurement device 300 is configured with a thermal probe 322, the thermal probe 322 in signal communication with an attached signal processor 310 and transmitter 320, the transmitter 320 in turn sending a signal, preferably a wireless signal (such as an RF signal) 305, to a receiver 420 of the heater 400. This signal is transmitted to a preferably programmable controller 430 of heater 400 to regulate the power output from power source 410 to heater element 460, which provides a predetermined power and/or temperature time profile to achieve the desired cooking result. The thermal measurement device 300 preferably contains a power supply 301, a transmitter 320, and the necessary signal processing unit (e.g., microprocessor or controller 310) to convert the temperature probe output to a wireless transmission, such as an RF signal. The controller 430 is preferably programmable with a series of programs or modes of operation that the user can select, options for user input of parameters such as influencing the application of the operating program and temperature cycling, and preset modes (the controller can operate according to a pre-entered program that can be updated or changed in the future). The selection of programs and entry of parameters may be made using any conventional user interface and control panel, such as switches, remote controls, and loading programs from other devices.

The RF signal receiver 420 of the heater 400 may be integrated with the machine housing of the controller 430, the power supply 410, and the induction heating coil 460. In this case, when the heater element 460 is an induction coil, it is preferable to carry the RF signal at a frequency (typically 315MHz) much higher than the induction field frequency (typically 70 kHz). In this case, even in the presence of RF noise generated by the induction furnace, only general commercial measures are necessary to achieve the required signal-to-noise ratio. In addition, the encoding scheme is preferably configured to reduce the read error rate, however, one tenth of the error rate will not affect the cooking process in the preferred process control method of the induction furnace controller 400. An aspect of the presently preferred means of reducing the error rate is also an encoding scheme for transmitting the temperature information twice, each transmission having a predetermined delay period in between, so that if one of them is successfully decoded, updated temperature information will be obtained. It should be understood that the controller 430 is preferably a programmable controller operable to provide different cooking times, temperatures and time-temperature profiles suitable for the food material to be cooked.

In addition, it is also preferable to limit the transmission of temperature information using the controller 330 to ensure the life of the battery or power supply 301. Where the temperature measurements of the sensor 300 are transmitted to the heater 400 by wireless radio frequency transmission, the transmission need not be continuous during t1 to t3 (particularly during t1) unless a vacuum is manually drawn on the container. It is not necessary to transmit the temperature value until about 90 deg.c. It is required to measure and send a temperature value to the controller 430 at a later stage of the cooling process (t2) (requiring several seconds to cool the contents of the pan by 0.1 c). In the reheat cycle, the temperature changes very slowly most of the time.

Each time the controller 430 receives a temperature measurement that is the most recently updated temperature of the sensor (delayed by only the processing time). Thus, in the preferred embodiment in which the heating time is controlled in response to temperature changes, the time at which the data is received when a decision is needed is recorded by the processor 430, i.e., the inductive or other thermal heating element body controller 430 will use the respective signal or signal package as a reference. Thus, by limiting the time of such transmissions in relation to temperature stability, power may be conserved. More specifically, it is preferred that temperature measurement controller 330 be operated to initiate transmission 310 at a frequency of at least every second (difference in consecutive readings greater than 0.5℃), every two seconds (difference greater than 0.25℃), and every four seconds (difference greater than 0.125℃). In this scheme, the number of transmissions required is greatly reduced, thereby reducing power consumption by half.

In this cooking method, the food 1 is optionally supported above the inside bottom of the container 110 by a plate, tray or rack 5. A plate, tray or stand 5 may be used to raise the food 1 above the water level 2 covering the bottom 115 of the container 110. When the gasket 250 or another member is used as a one-way valve, once the steam displaces at least a portion of the internal air in the container 110, the pressure will drop such that when the steam cools and condenses (rather than air being drawn back into the container), the condensation of water from the steam creates a partial vacuum in the container. The lid 200 has sufficient weight in proportion to the flexibility of the gasket 250 such that the gasket 250 sealingly engages the rim 113 of the container 110 and the lower rim 214 of the lid 200 when the pressure drop due to the condensation of the heated water vapor reduces the pressure inside the container 110.

While the absolute vacuum during subsequent cooking is temperature dependent, it is highly desirable to vent enough air so that when the container 110 is cooled down to room temperature as a whole, the partial pressure of any air in the sealed and partially evacuated container is measured to be much less than the partial pressure of water vapor, more preferably the air has a partial pressure of less than about 0.3 bar.

In a preferred embodiment of the method, a low pressure steam environment is formed in the cooking container 110 by the steps in the flowchart of fig. 2. The first step is to provide a container 110 capable of holding a fluid (step 101) and to add the food material (step 102) and an aqueous fluid (step 103) to the container 110 prior to sealing the container 110 with the lid 200 (step 104), for example by engaging its rim 113 with a gasket 250 disposed around the lid rim 214. In a preferred mode or embodiment, the bottom 115 of the vessel 110 is placed on the heater 460 and the heater is energized (105) for a sufficient time to raise the internal temperature of the fluid to T1, then held at T2 and the heater 460 is de-energized in step 106. It should be understood that the above-described methods are applicable to the various embodiments of the cooking vessel, lid and sensor disclosed herein.

The purpose of the heating in step 105 is to convert a sufficient amount of water vapor to displace atmospheric species in the vessel 110. Next, after step 106, the interior of the container 110 is cooled to a second temperature (T2 or T3) lower than the first temperature (T1), wherein condensation of water vapor within the container 110 causes the internal pressure to decrease sufficiently to cause the lid 200 to seal the rim 113 of the container 110. Next, in step 107, the container is maintained at least one second temperature (T3) for a predetermined amount of time (T3) (preferably from the end of T2).

It will be appreciated that for delicate foods requiring rapid cooking, it is desirable that T1 be as brief as possible to minimize exposure of the food to the maximum temperature T_maxAnd quickly reaches a cooking temperature T3 or T3'. The best way to accomplish this is to use a vessel 110 that is comparable in size to the food being cooked and that does not have excessive excess space around the food and avoid adding excessive amounts of fluid. While the volume of fluid must be large enough to expel air, it is greater than 1000 for water to steam at 1 atm: 1 is still small. If too much water is used relative to the size of the vessel 110, a large thermal mass of hot water is left behind and the time to cool to T2 or T3' is extended. Thus, in most applications with a container capacity of 1-6 liters, only 30 to 60 milliliters is sufficient.

The induction vessel 110 has a magnetic or other susceptor layer 115' at the outside bottom 115 of the vessel 110 that is directly heated only by eddy currents generated therein when the induction coil is energized. When the vessel 110 and its contents are not heated by the thermal mass of the non-radiative heater or any other portion of the vessel (other than the contents), it will be simpler to control the temperature within the vessel since the vessel and its contents are the only thermal mass that can cause the control temperature to be exceeded. In the case of a radiant heat source such as an induction base plate, the circulating vapor will respond quickly to the various conditions of heating the receptor layer in the bottom 115 of the container, since little water is required to replace the air in the container. Where other radiant heat sources are used (e.g., infrared heaters), the induction heating process is preferably very thin and has a small thermal mass of layer 115' so that energy is quickly transferred to the interior of vessel 110 upon internal heating.

In the fully or deeply evacuated container 110, this vapor flow exposes the supported food 1 to a very uniform and temporarily stable temperature during t 3. Thus, the heat probe 322 entering the interior of the container 110 via the inlet 205 in the lid 200 provides an accurate measurement of the environment of the food. In addition, any change in temperature is also detected quickly. This has been demonstrated with the large diameter 32 cm pot shown in fig. 6A, resulting in two-position temperatures at various heating and vacuum levels shown in fig. 7-9.

In addition, various methods of controlling induction heaters with digital electronics are well known. U.S. patent No.5700996 discloses various ways of providing a predetermined current to a resonant coil of an induction hob and is incorporated herein by reference.

U.S. patent No.6630650 discloses a digital control system for controlling the output power of an induction cooker and is incorporated herein by reference.

U.S. patent No.8373102 discloses an induction cooker capable of automatic control of heat output, including in response to selection of a cooking mode, and is incorporated herein by reference.

With accurate and rapid temperature measurements (via radio frequency or wired connections) fed back to the power supply controller, the heat source 400 below the vessel 110 is energized to just maintain a steady temperature or any targeted temperature profile.

Fig. 4 schematically shows the temperatures and pressures in steps of the process of fig. 2. T2 is a temperature sufficient to create a deep vacuum (i.e., a 95% reduction in atmospheric pressure of 0.05 bar or 0.7 psi) prior to heating to the higher cooking temperature T3. If the desired cooking temperature T3 'is below T2, cooling is allowed to continue until T3' is reached and the heater 160 is re-energized at T2. T2 is generally about 180-190F.

In FIG. 2, the container 110 is heated at full power during T1 to reach T1 (less than or equal to 212F.). The vessel 110 is maintained at this temperature for a time t 2. It should be noted that t1 is measured by the control system and predicts the additional heating time t2 required for venting air from the container 110. As the air is exhausted, the power to the heater is reduced or eliminated so that the pressure drops during the start at t 3. When the measured temperature is the target cooking temperature T3', heating may be restarted. Alternatively, for higher cooking temperatures, the temperature should at least reach T2 to ensure sufficient vacuum before warming to the final cooking temperature T3. In a preferred embodiment, the user can visually confirm that sufficient vacuum has been achieved, which is no longer apparent as gasket 250 is forced and pushed along curvilinear edge 113. As the cooking time, T3 optionally includes the time required to drop the temperature from T1 to T3 after T2.

Referring again to fig. 2, after cooking is complete, a warning or alarm light on the body of the heater 400 will activate (180), indicating that the cook can vent the container and remove the lid to consume the food in step 109 ", or alternatively reduce the temperature to hold the food until consumed in step 109", or alternatively re-heat the food to a consumption temperature in step 109 ".

It has been found that a low pressure steam atmosphere can heat food faster, even at temperature, than conventional vacuum cooking methods that seal food in a plastic bag.

Although it is not necessary to specifically create a vacuum by boiling water at atmospheric pressure, the optimal conditions for evacuating the vessel 110 have the following benefits: the food surface is initially steam sterilized at a Tmax or about 209-212F at a lower cost and with the addition of an external vacuum pump for greater reliability. In an additional embodiment, a mechanical vacuum pump may be housed in the thermal sensor 300 and run for a predetermined time before the thermal sensor sends a radio frequency signal to the heater 400 to begin heating the water.

By placing the delicate food items on a rack or plate supported above the bottom of the container 110, overcooking of the delicate food items during t1, t2 may be avoided. Or alternatively an insulating layer, such as a plastic film, bag, waxed paper, aluminium foil or a package or seal of organic and/or edible material (e.g. parchment, grape leaf, fig leaf or banana leaf, corn husks, etc.).

Alternatively, the vacuum may be established mechanically (e.g., by vacuum pump 500 as described in other embodiments). In FIG. 16B, the pump is integrated into the thermal sensor housing 300 and air is exhausted through the tube 501 in the grommet, where the thermal probe 322 is concentric with the tube 501. The double arrows indicate air discharge paths from the pipe 501 to the pump 500 and from the pump 500 to the exhaust port 502 on the side of the housing 300.

If the container 110 is small (relative to the food) and the amount of water or other aqueous fluid added (to produce the steam that expels the air) is not excessive, the interior of the container 110 will quickly cool below 212 ° f and reach the desired cooking temperature, thereby avoiding over-cooking of delicate food items. In this case, the thermal mass of the food ensures that the exterior is heated only to 212 ° F. In addition, supporting the food on a support that is further from the external heat source also prevents overheating of the food.

Excess fluid (i.e., more than is needed to generate the boiling water film shown in fig. 1) will slow the rate of cooling to cooking temperatures that can be as low as 128-140 ° F for cooking proteins, since excess water is simply an excess heat mass that slows the cooling process. This is partially illustrated in fig. 4 and 19, which depict the temperature change time required to reduce the pressure in the vessel 110.

Alternatively, more robust or larger food items may be grilled in the container at high temperatures on one or more sides before arranging the low temperature cooking mode at a controlled temperature, thereby cooking the food items through thickness. The juices and mixed flavors produced during grilling in combination with the addition of wine, beer, fruit juices and meat, poultry, fish or vegetable soup and the addition of other flavorings can be used to form sauces or marinades. It has now been found that subsequent cooking at low temperatures in a sealed container retains and enhances the flavour formed during grilling and infuses it into food. In contrast, unsealed atmospheric pressure steaming can strip the natural flavor and vitamins of the food.

The cooking device and method of the present invention are therefore proposed to produce food of a quality comparable to or even often superior to slow vacuum cooking, and in a shorter time, without the need for bagging or vacuum sealing the food.

Referring again to fig. 1, after the air within the vessel 110 is driven off (by a pump or steam), a thin layer of water or other aqueous fluid 1at the bottom of the pan (or chamber) is heated by an external heating plate or other heat source 460 and boils at a reduced pressure and at a low temperature. The arrows indicate the inherent water vapor circulation that results when the water temperature rise breaks the equilibrium in the vessel and more water vapor is produced. As will be described in detail below, although the heated steam rises to the top of the container 110, when the induction cooker main body is used as the heating element 460, the temperature inside the container 110 can be easily controlled. In this case, the temperature in the center of the container 110 is more constant even though the temperature is measured at the thermal probe 322 inside the container 110 directly below the cover 200 for control purposes.

Without wishing to be bound by theory, it is presently believed that the osmotic power of the circulating steam rapidly permeates certain foods and is more efficient in transferring heat relative to the water bath, thereby evacuating the sealed food. This is partially confirmed by the ability of certain foods to absorb flavors from flavors added to the food as well as aqueous fluids. Such a flavour may be produced by a flavourant disposed on a food product (e.g. ginger, garlic, green onion, lemon grass) or placed in an aqueous fluid. Since the vessel 110 is sealed during cooking, volatile aromatic compounds are not lost to the outside atmosphere, but are retained and concentrated as aromatic elements.

However, the beneficial circulation of such low pressure steam is enhanced when air is driven off and is always excluded. This condition can be achieved by an optimal gasket design that allows the air-purging vapor to escape during t1 and t2, and form a tight seal at the transition of the initial condensation of the vapor at the beginning of t 3. If the gasket does not seal the container 110 immediately upon cooling, cooling air is drawn in and thus a high vacuum condition is not achieved that transfers heat from the susceptor at the bottom of the container uniformly and quickly to the water vapor, resulting in greater temperature fluctuations as shown in fig. 7-9. In this case, the food is easily overheated and exposed to oxygen which may destroy certain flavors during a long cooking period.

It will therefore be appreciated that the full benefits of the innovative cooking apparatus and method can only be realized if the configuration of the vessel 110, heating and measurement, method and control scheme are optimized to operate in the cooperative manner disclosed herein.

Fig. 4 shows a preferred control scheme for maintaining a constant temperature or series of constant temperatures after T3 is reached. However, the control method of step 107 may employ any known process control method. The presently preferred method employs a series of short bursts of energy from the sensing body 400 to increase the temperature when the lower control limit is reached. The Lower Control Limit (LCL) is preferably set 0.25 ℃ below T3, while the Upper Control Limit (UCL) is set 0.375 ℃ above or at the desired cooking temperature T3.

Thus, FIG. 3 shows the short power pulses in time (Pn, P)_n+1、P_n+2) A schematic depiction of an application of (a), showing a typical measured temperature response in a preferred control scheme. When the LCL is reached by cooling from the no power mode, the induction heater is energized for a predetermined short period of time, producing a pulse of preferably about 5 seconds in the case of a 600W output. Then, the temperature rises in response to the heating, reaches and reachesThe peak Tn associated with the power pulse of the facet. However, due to the heating delay, after the heating pulse, the measured temperature may actually drop slightly below the LCL before rising. The controller 430 records Tn after each pulse, and the controller 430 is then operable to compare Tn to UCL, LCL, and T3 values, such that following a subsequent pulse (P) as follows_n+1) I.e., when Tn is below T3, the pulse is extended to increase the energy; when Tn is above UCL, the pulse is shortened to reduce energy; the same energy is applied in the pulse when Tn is between T3 and UCL or equal to either of T3 and UCL. Thus, when LCL is reached again, a subsequent pulse (P) is applied_n+1) And the pulse time is modulated based on the difference between Tn and T3. The pulse width or time is extended when the existing pulse causes the local temperature maximum Tn to be below T3, and is shortened when the existing pulse causes Tn to be above UCL. Similar modulation is experienced for subsequent power pulses applied when cooling to the LCL so that the temperature remains between the UCL and T3. This pulse width control method is preferably provided at the lowest power output setting. Alternatively, the output power may be increased instead of extending the pulse width.

Power higher than the lowest power can be used by reducing the power instead of shortening the pulse width. Alternatively, the temperature rise rate and maximum temperature after each pulse can be used to calculate subsequent pulse widths or powers to more accurately limit the temperature rise between subsequent temperature peaks.

Further, subsequent pulses of reduced power may be applied before the temperature reaches the LCL, thereby reducing fluctuations between the UCL and the LCL.

U.S. patent No.5004881 discloses an induction cooker body construction and power level control methods in an induction cooker (a combination of time duty control using power level and pulse width modulation control methods) that are suitable for use in the present disclosure and which are incorporated herein by reference.

Fig. 7 through 9 illustrate the temperatures measured at the probe 322 and the test heat probe on the rack 5 in fig. 6 over a range of conditions, showing the importance of purging air in step 105 to achieve the tight temperature control necessary for process control to provide equivalent cooking results to the water bath of the sous vide cooking apparatus. It will be appreciated that in actual measurement, inducing a current to the thermal probe 322 (e.g., a thermistor or thermocouple) may result in a brief negative peak in the output of the thermal sensor. Since these negative peaks are 6 ± 1 second in duration of the heat pulse, and the applied pulse should generally be no faster than 30-90 second intervals, these negative peaks can be ignored in the control scheme or removed using a band pass filter. When the UCL and LCL are between 0.5 ℃, a 600 watt 5 second pulse is typically applied every 40-200 seconds. Alternatively, the UCL may be set slightly above the target cooking temperature because larger foods requiring slow cooking also have their internal temperature gradually increased, while the heat transfer process is driven by the average cooking temperature between the UCL and the LCL.

As can be seen from fig. 7A to 7C, with most of the air excluded (0.08 bar) and the temperature sensing portion of the probe 322 located just inside the cover 200, a slightly higher temperature was measured after each power pulse, but the stent temperature was more stable with a variation of less than about 0.5 ℃ (about 1 ° F) (temperature difference between UCL and LCL). In addition, in a fully evacuated container 110, the probe and holder temperatures are well correlated to allow cooling from a first controlled temperature of 158 ° F to a second controlled temperature of 140 ° F when the heater is not energized.

In contrast, as shown in fig. 7B, with residual air equivalent to 0.3 bar, there is a significant thermal lag at the mount location and the mount temperature is less stable, floating at about 140 ° F. This thermal lag further reduces air emissions with water vapor (1 bar in fig. 7C), with a significant thermal lag from 158 ° F to 140 ° F throughout the cooling phase, and with a large float and variation in probe and holder temperatures.

Poor thermal control without air removal is most evident at low temperatures of about 120 deg., as shown in fig. 8A and 8B, where the LCL is 120 deg. F, the temperature of the probe 322 is compared to the temperature measured on the rack 5 at the food support location below the container rim 113. Under minimal residual air conditions (0.08 bar), the probe position changes predictably by about 0.8 ° F, the stent position stabilizes its change below 1 ℃ and the probe temperature does not exceed the UCL. However, since air is not removed, as shown in fig. 8B, the probe temperature is not controllable between the UCL and the LCL, thereby changing the stent temperature by about 2 ° F (greater than 1 ℃). Furthermore, the temperatures measured in the evacuated containers above 0.08 bar undergo a great fluctuation, even at higher temperatures in fig. 7B and 7C.

Fig. 9A to 9C show the great control stability over a series of temperature plateaus at 0.08 bar, including the cooling transition between them. At the highest plateau of 176 ° F and 158 ° F, the stent and probe temperature rises within the UCL after each power pulse. However, at the lowest plateau of 140 ° F and 122 ° F, the stent temperature is very stable and does not rise or float with the probe temperature.

It should be understood that where it is desirable to limit the initial temperature during air removal, it may be desirable to use a smaller vessel 110 or set the Tmax or time t2 (which somewhat diminishes the control capability within the UCL and LCL) lower.

The cooking method and apparatus avoids raising the temperature inside the food to a level that would detrimentally alter the texture, flavor, or nutritional content of the food. For proteins, cooking temperature is the primary determinant of doneness status, which together with optimal softness and moisture content provides satisfactory mouthfeel. Although some animal proteins with higher collagen content soften by extending the cooking time, overcooking the protein when the collagen dissolves can make the meat harder. By using the device of the invention, collagen can be slowly dissolved at low temperature without overcooking protein, harder meat becomes extremely tender without excess fat, and delicious sauces can be made in a pan.

The cooking process is believed to retain vitamins and flavors. Furthermore, the cooking method does not require the food to be sealed in a plastic bag. An additional benefit is that less water is required than for sous-vide cooking, where it is required to provide a water bath sufficient to submerge the entire plastic bag containing the food. Furthermore, in contrast to many types of sous vide cooking devices, the cookware need not be constantly filled with steam. However, it is also possible to seal the food in a plastic bag or other container and use low pressure steam as the heat transfer fluid.

It will also be understood that a less preferred but alternative temperature control and measurement device compatible with induction cookers is an external heat probe 120, which is mounted in the center of a heating plate with elastic means (e.g. springs), which is then urged into contact with the bottom of the cooking vessel 110. In another alternative temperature control and measurement device, the thermal probe or sensing portion 322 thereof may extend from anywhere into the interior of the vessel 110, such as the water 1, which may optionally be the bottom.

Fig. 10 to 11 illustrate the interaction between the preferred gasket 250 and portions of the preferred cooking vessel 110 and lid 200. The combination provides a quick and stable vacuum seal during the heating cycle of fig. 2 through 3, but allows the container to be used with other lids, including the lid shown in fig. 17 (where the thermal sensor is located outside the container). Lid rim 214 is configured to form a sealing fit with rim 113 of cookware vessel 110. To this end, the lid rim 214 includes a post portion 214a that is substantially parallel to the container sidewall 112 when the lid 200 is assembled with the container 110. The lid rim 214 also includes an outwardly flared flange portion 214b disposed at the free end of a cylindrical portion 214a that is generally parallel to the container bottom 115 when the lid 200 is assembled with the container 110. The cylindrical portion 214a and the flange portion 214b together form an inverted "L" shape to receive the washer member 250.

Lid rim 214 includes a pliable gasket 250 disposed within an interior angle defined between post portion 214a and flange portion 214b and extending around a circumference of lid rim 214. The gasket 250 generally has an upstanding "F" shape when viewed in cross-section to allow the gasket 250 to mate with and form a seal with the inner rim 113 of the container 110. The washer 250 includes an upper horizontal arm 251, a lower horizontal arm 252, a vertical portion 253 extending between the upper and lower horizontal arms, and a skirt 254 that is an extension of the vertical portion 253 and depends from the lower horizontal arm 252. The upper and lower horizontal arms 251, 252 taper in thickness toward their terminal ends (e.g., free ends) 251a, 252a, thereby providing greater flexibility at the free ends 251a, 252 a. However, the root or portion of each arm 251, 252 closest to the vertical portion 253 is thickened to provide support when the free end is deformed to conform to the curved shape of the inner surface 113a of the vessel rim 113 under the evacuated condition of the vessel 110. Upper horizontal arm 251 is longer than lower horizontal arm 252 to accommodate the curvature of container rim 113. Gasket 250 is oriented within the inner corner such that upper horizontal arm 251 abuts and sealingly engages lid rim flange portion 214b and vertical portion 253 abuts and sealingly engages lid rim post portion 214 a. In particular, the vertical portion 253 is shaped to conform to the outer surface shape of the cylindrical portion 214a, and thus, may be curvilinear in some embodiments. This feature ensures contact by providing a larger sealing area and secures the gasket 250 to the lid 200 when the container 110 is vented by lifting the valve 240 to the open position.

Gasket 250 has central ribs 255 formed on skirt 254 that are equally spaced around the circumference of lid rim 214 (fig. 10A). In the illustrated embodiment, the gasket 250 includes four ribs 255 spaced 90 degrees apart around the center of the gasket. The ribs 255 project outwardly from the skirt 254 toward the container sidewall 112. In the portion of gasket 250 between ribs 255, skirt 254 has a thickness th1 (fig. 10C), while in the portion of gasket 250 corresponding to ribs 255, skirt 254 has a thickness th2, where th2 is greater than th1 (fig. 10C). The ribs 255 help center, position, the lid 200 in the container rim 210 to ensure a repeatable vacuum seal and eliminate vibration during sealing.

Referring to fig. 11A, when the lid 200 is assembled with the container 110 in a non-vacuum state (e.g., the container interior space is at atmospheric pressure), such as during cooking or when the valve 240 is in an open position, the free ends 252a of the lid 200, the lower horizontal arms 252 contact the curvilinear portion 113a of the inner surface of the container rim 113 to support the lid 200 relative to the container. The arm free end 252a sealingly engages the curvilinear portion 113a over a relatively small area P1 (corresponding to the size of the wedge-type free end 252a along the periphery of the container rim 113). The initial contact area is sufficiently narrow to allow steam to escape without disturbing the alignment of the lid. When viewed in cross-section, region P1 generally corresponds to a single point of contact. In this position, upper horizontal arm 251 and skirt 254 of gasket 250 are spaced from container rim 210 and a vertical gap G exists between lid flange portion 110b and container rim 113.

Referring to fig. 11B, when the lid 200 is assembled with the container 110, the valve 240 is in the closed position (or the thermal probe 322 fills the eyelet 170 disposed in the perforation 205) and the container 110 is in a slight vacuum condition (such as occurs when vapors trapped within the container condense), the weight of the lid 200 and the atmospheric pressure expand the area contacted by the lower horizontal arm 252. By deformation of the lower horizontal arm 252 with more complete engagement, the contact region P1 expands to region P1 'and follows the shape of the container rim surface 113a, e.g., P1' > P1. Specifically, side 252b of lower horizontal arm 252 contacts curved portion 113a of the inner surface of container rim 113 to sealingly engage curved portion 113 a. In addition, upper horizontal arm 251 sealingly engages container rim surface 113a, thereby forming upper contact region P2, wherein upper arm 251 contacts rim surface 113a, and skirt 254 engages the inner wall of container 110 below rim 113, thereby forming lower contact region P3, wherein skirt 252 contacts rim surface 113a and/or container sidewall 112. Furthermore, as the lid is lowered, the vertical gap G provided by the gasket 250 decreases or disappears.

By providing multiple sealing locations (P1', P2, P3), vacuum seal reliability is improved and vibrations during and after sealing, which can cause an audible objectionable noise (squeaking), are eliminated. In addition, the described configuration prevents the gasket 250 from sticking to the rim 113 when the container 110 is vented by lifting the valve 240 or removing the thermal sensor 300.

Fig. 12A-14F illustrate another aspect of the preferred lid 200, which includes a handle 215, and an exhaust valve 240, which can replace the heat probe when the container is in normal use, or in the oven shown in fig. 17. In an alternative embodiment of the present invention, the alternative container venting means 111 is preferably a sealable exit hole in the lid 200 of the container 110, as shown in fig. 6A.

Referring to fig. 12A-12D, although the handle assembly 215 is illustrated with the valve 240 disposed in the opening 205, the handle assembly 215 is not limited to this configuration. For example, in the alternative handle assembly 215, the valve 240 is replaced with a probe 322 and an eyelet 170 that lines the opening 205 and supports the probe 322. The eyelet 170 includes a cylindrical sleeve 171, the cylindrical sleeve 171 including an outwardly extending stop flange 173 formed at one end thereof. When the eyelet 170 is disposed in the opening, the stop flange 173 rests on the ring member base plate 232 and retains the eyelet 170 in a desired position relative to the opening. The inner surface of the sleeve 171 defines an internal bore 172. The outer surface of the sleeve 171 is shaped and sized to correspond to the shape and size of the opening 205. A temperature sensing probe 322 is sealingly received in the grommet bore 172, and an outer surface of the grommet sleeve 171 fits within the opening 205 and forms a seal therein. Thus, the handle assembly 215 allows the temperature sensing probe 322 to be inserted in a sealed manner in the container 110. The wireless transmitter 300 may be powered using an external switch 382. Removing the temperature sensing probe 322 from the bore 172 allows venting of the cookware vessel 110. In other embodiments, the thermal sensor may be replaced with a plug that fills the bore 172, in the grommet 170, to provide an alternative barrier that cooperates to seal and close the opening 205. Such a plug 111 in fig. 6A is also a vacuum sealing device.

In the embodiment illustrated in fig. 13-14F, the valve 240 is generally recessed within the handle 220 when in the closed position. However, in some embodiments, the valve 240 may have a portion that protrudes beyond the outer surface of the handle 120 when in the closed position.

In the illustrated embodiment, the central opening 205 is circular in shape, but it is contemplated that the opening 205 may alternatively be formed having other shapes, including oval and rectangular.

Although gasket 250 is described herein as having a generally upright "F" shape, gasket 250 is not limited to this configuration. For example, in some embodiments, gasket 250 may have a "U" shape that opens to the rim of the container.

Although the cover 200 is described herein as being formed of metal, it is not limited to this material. For example, in some embodiments, the cover 200 is formed of glass or plastic. In other embodiments, the cover is formed of metal and transparent glass. In still other embodiments, the metallic lid is coated with enamel or other material.

Although the cover 200 is described as having a single central opening 205, in some embodiments, such as fig. 6, it is not limited to this configuration. For example, in some embodiments, the lid 200 includes a plurality of openings centered in the center of the lid. In the illustrated embodiment, the handle 120 is formed of a material that is stable at high temperatures. In some embodiments, this material is rubber or silicone rubber, or a thermoset plastic resin, such as a phenolic resin or the like.

As shown in fig. 12D, the removal of the thermal sensor 220 provides the vent 111 using the sidewall of the thermal probe 322 to seal the container 110 via the gasket 116.

The cap 200 is a dome-shaped member having an outer surface 202 and an opposite inner surface 204 that collectively terminate at an annular cap rim 214. The cover 200 is formed of metal and includes a central circular opening 205 that extends between the outer surface 202 and the inner surface 204.

Referring to fig. 13-14F, the handle assembly 215 is used to lift the lid 200 and control the vacuum pressure within the container 110. The handle assembly 215 includes a handle 220, a ring member 230 that secures the handle 220 to the cap 200, and a valve 240.

The annular handle 220 is located at the geometric center of the lid 200 and surrounds the opening 205. Handle 220 is formed from a material that is stable at high temperatures and has a first end 222 that abuts lid outer surface 202 and follows the shape of lid outer surface 202. The handle 220 has a second end 224 opposite the first end 222. The handle second end 224 defines an outwardly projecting shoulder 223 that serves as a gripping surface and is wedge-shaped to be slightly recessed relative to the shoulder 223 at a central portion thereof. The handle 220 has an inner surface 225 that extends between a first end 222 and a second end 224, has a uniform diameter, and has a diameter that is larger than the diameter of the opening 205. Equidistantly spaced slots 228 are formed in the handle inner surface 225 and correspond in size and shape to the size and shape of the struts 236 provided on the ring member 230, as discussed below. A peripheral groove 221 is formed in the handle second end 224 at a location generally midway between the inner surface 225 and the outer surface 226 of the handle 220. The annular portion of the handle second end 224 between the inner surface 225 and the groove 221 forms a land 227. Lands 227 and grooves 221 are configured to receive and support the flange portions of ring member 230, and slots 228 are configured to receive and support struts 236 of ring member 230, as discussed below.

Referring to fig. 13, 14D, 14F and 15A, the handle assembly 215 includes a ring member 230 configured to secure the handle 220 to the cover 200. The ring member 230 surrounds the opening 205 and is disposed between the handle 120 and the valve 240. The ring member 230 has a cylindrical support portion 235, an annular base plate 232 connected to an end of the support portion 235 facing the cover, and a flange portion 231 connected to an opposite end of the support portion 235. In some embodiments, support portion 235 is formed from a strut 236 extending between flange portion 231 and base portion 232. The base plate 232 is concentrically disposed about the lid opening 205 and is secured to the lid outer surface 102, for example, by welding. To this end, the base plate 232 includes spot welding centering holes 239 spaced apart from each other. The flange portion 231 projects outwardly from the support portion 235 in a direction away from the opening 205 and toward the lid rim 214. The shape of the flange portion 231 follows the land 127 and the groove 121 of the handle 120. In use, the base portion 232 is secured to the outer surface 102 of the cover 200 to surround the opening 205, and the post 236 is received in the slot 128. Because the slots 128 engage the struts 236, the handle 120 is prevented from rotating relative to the cover 200. In addition, the flange portion 231 is received within and engages the land 127 and the groove 121 of the handle 120, and thus the handle 120 remains against the outer surface 102 of the lid 200.

Referring to fig. 13 and 14A-14C, the handle assembly 215 includes a vacuum sealable valve 240 disposed concentrically within the ring member 230 and the annular handle 120. The valve 240 is resilient and has a disc-shaped main portion 244 disposed within the ring member 230 so as to be movable relative to the ring member 230. The valve 240 further includes a generally cylindrical stem portion 245, and an elongated relief portion 246. The stem extends from the cap-facing side of the main portion 244 and is shaped and dimensioned to seal the cap opening 205 in some valve positions 240 relative to the handle 120. The relief portion 246 extends from the cover-facing side of the stem portion 245. The release 246 terminates in a pair of legs 248 that project from opposite sides of the release 246 in a direction generally parallel to the cover 200 (fig. 14B). The leg 248 is larger in size than the opening 205 so that the leg 248 retains the valve 240 in the opening 205. In addition, the relief portion 246 has a small cross-sectional dimension in a direction transverse to the legs 248 relative to the stem portion 245 and the opening 205 (fig. 13 and 14A). In other positions of the valve 240, the release portion 246 is configured to provide venting to relieve the vacuum within the container 110 by allowing outside air to enter the container 110, as discussed further below.

Referring to fig. 15B, the valve 240 is operable to translate between a first closed position (fig. 15B) and a second open position (fig. 15C) relative to the handle 220 and the opening 205. In the closed position, the valve 240 is retracted into the space defined by the handle inner surface 225. As a result, the trunk 245 is disposed in the opening 205 and sealingly obstructs the opening 205. That is, when the valve 240 is in the closed position, the trunk 245 prevents air from flowing through the opening 205. In the open position, the valve main portion 244 is partially advanced outwardly from the handle 220 such that the stem 245 is withdrawn from the opening 205. In this position, the backbone 245 is located on the outer surface side of the cover 200 to be adjacent to the opening 205 and aligned with the opening 205. In addition, the relief 246 extends through the opening 205. Since the relief portion 246 has a size smaller than that of the opening 205, air may flow through a gap between the relief portion 246 and the opening 205, and thus the container 110 is vented.

The valve 240 is manually opened or closed at the discretion of the user. To this end, the outer face 244a of the main portion 244 includes a setback 241 configured to allow grasping of the valve 240.

The valve main section 244 may include features that allow a user to visually determine the position of the valve 240 relative to the cap 200. In the illustrated embodiment, the outer peripheral edge 244b of the main portion 244 includes a circumferentially extending groove 243, and the indicator ring 242 is disposed in the groove 243. The indicator ring is formed with a color that contrasts with the color of the handle 120 and possibly other portions of the valve 240. When the valve 240 is in the open position (fig. 15C), the indicator ring 242 is visible to the user, indicating that the valve is in the open position. When the valve 240 is in the closed position (fig. 15B), the valve main portion 244 is retracted within the handle 220 and the indicator ring 242 is not visible to the user, indicating that the valve 240 is in the closed position.

In fig. 16, the container is capable of operating above or below atmospheric pressure, wherein air and steam are initially vented through the valve prior to vacuum mode operation, wherein the valve is one-way or closed after time t 2. After time t2 the valve may be manually closed using a signal such as light, sound from base 400 for user perception. Alternatively, the valve may be closed by a solenoid-type valve via an electronic signal from the controller 430. The cap 200 has bayonet or jaw clamps to maintain pressure after the valve is sealed. This configuration allows cooking at controlled temperatures above about 190 ° f, raising the safe operating pressure set by the safety relief valve once the valve is closed, which is typically between about 5psi to 15 psi.

Fig. 17 is a cross-sectional elevation view of another embodiment of a cooking apparatus 1000 suitable for low-pressure steam cooking, wherein a vessel 110 containing raw food or food to be heated is within another vacuum vessel 700. Preferably the container 700 is closed with a hinge 750, the hinge 750 attaching a lid 17200, the lid 17200 containing a temperature sensor 17122 for measuring the temperature of the water vapor. Gasket 17250 seals lid 17200 to lower portion 730, with lower portion 730 extending above container 110 to the hinged rim. The container 700 may also contain a flat heating member 17460 in direct contact with the bottom 115 of the container 110. More preferably, the second thermal sensor 17120 is spring loaded and in contact with the outer bottom 115 of the container 110, preferably in the center of the flat heating element 17460 but is not directly heated by the flat heating element 17460. The flat heating element 17460 may be heated by a resistive heating coil, with the current controlled by the controller 17430 in response to predetermined times and temperature rules as described above, as measured by one or more of the thermal sensors 17122 or 17120.

More preferably, the control system 17430 is integrated into the base 17100 of the apparatus 1000 (including the container 700) and connected to the flat heating member 17460. The control panel and appropriate status indicators can be external to the container 700 and/or the base 17100.

The water vapor temperature sensor 17122 may then be in signal communication with the controller 17430 via a wired connection, such as one wired connection 730 extending from the lid 710 to the sidewall outside the container 700. Alternatively, the water vapor thermal sensor 17122' may be embedded in or extend from the sidewall of the inside of the container 700, above the food-containing container 110, or spaced apart from the food-containing container 110. The vent 17111 in the lid 17200 is preferably a one-way releasable valve that prevents pressure from building up within the container 700, but closes itself to create a vacuum, and because it is easily opened by pulling upward, such as 220.

Thus, the device 1000 of fig. 17 has the advantage that the external power of the controller and heater avoids the need for a battery powered or other RF transmitter in the lid, simplifying consumer use and reducing costs. As with other embodiments, the device 1000 is also capable of other cooking modes, such as rice cooking or slow cooking of liquid ingredient mixtures with or without venting air depending on the state of the vent/valve 111.

In another aspect of the invention, illustrated in fig. 18, the vacuum compatible container 110 is filled with a food material, evacuated to a partial vacuum, and then introduced into a temperature controlled oven 18400 in which the temperature is below 100 ℃. The vacuum in the container 110 can be achieved by a heating process to create steam and displace air, followed by a slight cooling on condensation to create a vacuum. This mode avoids the need for an external electronic thermal sensor 300 in the cover 200. Replacement of air with steam can be done on regular storage heads or cooktops and induction bases as long as the heating cycle is timed and/or measured to expel most of the air, as described with respect to fig. 2 and 4.

Alternatively, the container 110 may be evacuated with a hand-held or removable vacuum pump conduit via a closable or one-way valve. The surrounding oven 18400 then replaces a heat source, such as an induction furnace, and as long as the oven 18400 is deployed with an accurate internal temperature measurement device 18322 and an advanced heat control system, such as a PID-type feedback system, to maintain the temperature at a constant level, the heat measurement device does not need to enter the vessel. Convection ovens are particularly suitable for this purpose because the convective mixing of the air provides a uniform temperature. As long as the temperature measuring device 18322 measures the oven air temperature, the food material inside the container will not exceed this temperature and the entire food contained therein will slowly reach this temperature.

The convection oven 18400 in fig. 18 would preferably deploy an internal exhaust system 18001 wherein a fan 18430 draws air from a portion of the oven 18400 and then returns the air to a different portion of the oven by passing it over the heater element 18460. At least one heat probe 18322 is in signal communication with the control system to continuously measure at least one of the internal oven temperature or the temperature within the container (18322'), inserted in the gasket or lid 200 or other sealable portion of the lid vent 240. The opposite portion of probe 18322 'will be connected to the oven's internal controller via guide 18301 of the internal oven wall after the container 110 is evacuated, using a hand held pump or pump tube, or by heating and cooling at the cooking tip/induction base. The control system may energize the heaters and or fans as required to maintain a predetermined temperature or temperature profile, as generally described with respect to other embodiments. This approach has the advantage in a restaurant or other commercial kitchen that a single oven can hold multiple containers for cooking and storage until it is desired to taste the food.

It should now be understood that the inventive cooking apparatus and method is intended to be deployed on induction hobs built into counter tops and including space for multiple containers, or in kitchens where it is desired to use multiple devices 1000 simultaneously. To avoid confusion of the signals sent by the different transmitters 320 in each thermal sensor 300, the sensors may transmit at different frequencies. However, a simpler arrangement is illustrated in fig. 20, in which each sensor sends a pair of signal signals (S1 and S2) at respective times of transmission of the signals (or signal packets for temperature measurement or control instructions) to the receiver 420 and hence the power controller 430, with different predetermined time intervals between each signal in the pair. Thus, the controller 430 of each of the devices 1000 is programmed to only identify pairs of signals at associated predetermined intervals. In the worst case scenario shown in fig. 19, when the first and second thermal sensors 330 are simultaneously transmitting the first signal in a pair, each controller 430 and 430' will only receive 3 signals or signal packets and is further programmed with instructions operable to ignore the value of the first signal or signal packet and use the second signal or signal packet at the appropriate delay time (from the overlapping pair) for control purposes.

Fig. 20 illustrates another important advantage of the inventive cooking apparatus and method over low-temperature-under-vacuum (Sous Vide) cooking in that large and irregularly shaped food items, such as whole fish and poultry, with open body cavities can be cooked in an accelerated method using multiple temperature control stages. The same mode may be deployed in rice cooking or slow cooking liquid ingredients and mixtures where it is desired to briefly heat or monitor (seer) food at high temperatures, followed by cooking at low temperatures. Fig. 20 is a schematic diagram of the temporal variation of the temperature in the container of fig. 1 resulting from another mode of operation according to the flow chart of fig. 2. First, at full power to energize the heater 460, the controller 430 records the time T1 to T1 (generally 210 ° f). The time T2 at which the maximum power is maintained (during which T is reached) is calculated as described above_max) And exhausting the air and the heater is then de-energized to allow cooling to the first predetermined cooking temperature T2. T2 is maintained for time T2' using any of the process control schemes described above. In the case of large birds, whole fish, or frozen seafood at 3-4 pounds, T2 is about150 to 180 ° f and a holding time t3 of about 10-30 minutes. Then after T2' is reached, the heater is again de-energized to allow cooling to T3, during which time T3 is maintained for time T3 using any of the process control schemes described above. T3 is generally the final cooking temperature, corresponding to the degree of cooking of the protein, such as about 128-135 ° f for fish or seafood, 130-165 ° f for meat or poultry, where T3 depends on food thickness or weight. In this example, T3 is the optimum temperature to avoid overcooking and dehydration of proteins, keeping the cooked food material satisfying moisture and aroma. More stages may be deployed between T and T3 to speed cooking and gradually lower the temperature to avoid overheating the exterior of the food at an early stage.

After T3, the heater controller 430 may be operable to maintain the food at a lower temperature, say T4, until it is desired to taste the food. In this case, a manual command may be entered to heat the interior of the container 110 to T4', which is the final taste temperature, generally 150 to 170 ° f, to merely warm the exterior of the food to this taste temperature, which takes only about 1-4 minutes. The staged heating illustrated in fig. 20 allows large poultry and whole fish that cannot be done in the Sous Vide cook to be completed in less than 1 to 1.5 hours. Frozen fish and shellfish may also be used in this cooking method and will not be overheated during the initial phase of creating steam to expel the air. This staged heating is possible because the air discharge state (where low pressure steam fills the interior of the vessel) allows for rapid and accurate transitions between temperature stages without exceeding the desired control limits.

Also after cooking is complete, the food may remain at the final cooked or lower temperature until the food is ready to taste, in which case the controller 430 may be manually commanded to increase the temperature to a fourth or taste temperature for a limited time that will still avoid overheating the interior, but give the food a warmer aroma and mouthfeel from the slightly warmer exterior of about 160 to 170 ° f. The ability to rapidly heat the food to a slightly higher temperature (T4 in fig. 3) than the cooking temperature (T3 or T3') prior to tasting enhances the mouthfeel of warmer foods and increases aroma release without over-cooking. This is not practical when using a water bath as the cooking medium because it takes a relatively long time to increase the water bath temperature, and when the vessel 110 is heated by the inside of the induction coil, the water vapor temperature will increase almost immediately.

While the invention has been described in connection with a preferred embodiment, it is not intended to limit the scope of the invention to the particular form set forth, but on the contrary, it is intended to cover such alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.

Claims (13)

1. A cooking assembly, comprising:

a. an induction heating substrate having an upper surface for supporting a cookware vessel, one or more induction heating coils disposed below the upper surface, and a programmable controller responsive to energize the one or more induction heating coils,

b. a cookware vessel having a base adapted to be supported by the upper surface of the induction heating base, a generally upstanding sidewall extending upwardly from the base and terminating in a rim, the sidewall surrounding the base to form an interior portion capable of retaining a fluid,

c. a lid, and a gasket engaged with said cookware vessel at its rim adapted to form a vacuum seal therewith, said lid having at least one sealable perforation formed in its surface,

d. an emitter device adapted for removable supportive engagement with the lid and in signal communication with the programmable controller, the emitter device having a heat probe that accesses an interior portion of the container via the sealable perforation of the lid,

e. wherein the programmable controller is operable to energize and de-energize the one or more induction heating coils to maintain a predetermined temperature input to the programmable controller in response to the temperature measured by the thermal probe,

f. wherein the gasket and the sealable perforation in the lid are adapted to maintain at least one of at least a partial vacuum and a pressure greater than atmospheric pressure in the interior portion of the container,

g. wherein the cooking assembly comprises means for reducing the partial pressure of the air in the cookware vessel to 0.3 bar and below,

wherein the programmable controller is operable to de-energize the induction heating coil a calculated time after receiving a signal from a transmitter that a first predetermined temperature was reached, wherein the time to reach the first predetermined temperature is used to determine the calculated time.

2. The cooking assembly of claim 1, wherein the means for reducing the partial pressure of air in the cookware vessel to 0.3 bar and below is the programmable controller that first energizes the induction heating coil at least until the heat probe detects a temperature of about 200 ° f.

3. The cooking assembly of claim 1, wherein the transmitter is wired or wireless.

4. The cooking assembly of claim 1, wherein the calculated time is sufficient to provide generation of an amount of water vapor operable to vent air from the container such that a vacuum seal is formed between the lid and the rim via the gasket after the calculated time to de-energize the induction heating coil.

5. The cooking assembly of claim 4, wherein the calculated time is sufficient to provide generation of an amount of water vapor operable to expel air from the container for a time of up to about 94 degrees, minus 60 seconds, and then divided by 2.

6. A cooking assembly, comprising:

a. an induction heating substrate having an upper surface for supporting a cookware vessel, one or more induction heating coils disposed below the upper surface, and a programmable controller responsive to energize the one or more induction heating coils,

b. a cookware vessel having a base adapted to be supported by the upper surface of the induction heating base, a generally upstanding sidewall extending upwardly from the base and terminating in a rim, the sidewall surrounding the base to form an interior portion capable of retaining a fluid,

c. a lid, and a gasket engaged with said cookware vessel at its rim adapted to form a vacuum seal therewith, said lid having at least one sealable perforation formed in its surface,

d. an emitter device adapted for removable supportive engagement with the lid and in signal communication with the programmable controller, the emitter device having a heat probe that accesses an interior portion of the container via the sealable perforation of the lid,

e. wherein the programmable controller is operable to energize and de-energize the one or more induction heating coils to maintain a predetermined temperature input to the programmable controller in response to the temperature measured by the thermal probe,

f. wherein the gasket and the sealable perforation in the lid are adapted to maintain at least one of at least a partial vacuum and a pressure greater than atmospheric pressure in the interior portion of the container,

g. wherein the cooking assembly comprises means for reducing the partial pressure of the air in the cookware vessel to 0.3 bar and below,

wherein the transmitter is wireless and comprises a processor for calculating a transmission time based on a change in temperature over time.

7. A cooking assembly, comprising:

a. an induction heating substrate having an upper surface for supporting a cookware vessel, one or more induction heating coils disposed below the upper surface, and a programmable controller responsive to energize the one or more induction heating coils,

b. a cookware vessel having a base adapted to be supported by the upper surface of the induction heating base, a generally upstanding sidewall extending upwardly from the base and terminating in a rim, the sidewall surrounding the base to form an interior portion capable of retaining a fluid,

c. a lid, and a gasket engaged with said cookware vessel at its rim adapted to form a vacuum seal therewith, said lid having at least one sealable perforation formed in its surface,

d. an emitter device adapted for removable supportive engagement with the lid and in signal communication with the programmable controller, the emitter device having a heat probe that accesses an interior portion of the container via the sealable perforation of the lid,

e. wherein the programmable controller is operable to energize and de-energize the one or more induction heating coils to maintain a predetermined temperature input to the programmable controller in response to the temperature measured by the thermal probe,

f. wherein the gasket and the sealable perforation in the lid are adapted to maintain at least one of at least a partial vacuum and a pressure greater than atmospheric pressure in the interior portion of the container,

g. wherein the cooking assembly comprises means for reducing the partial pressure of the air in the cookware vessel to 0.3 bar and below,

wherein the lid further comprises an annular handle surrounding a sealable perforation in the lid, and the transmitter is adapted to be embedded within an inner ring of the annular handle, wherein the heat probe passes through and seals the sealable perforation via a removable grommet.

8. A treatment method for cooking, the treatment method comprising the steps of:

a) providing a container capable of holding a fluid, the container having a lid sealably engaged with a rim;

b) introducing at least one of water and an aqueous fluid into the vessel;

c) placing food material in the container;

d) placing the lid on the container;

e) heating the vessel to a first temperature at least until water is converted to a sufficient amount of water vapor to replace atmospheric constituents of the vessel;

f) reducing the heating power to the container to bring the container to a second temperature lower than the first temperature, wherein condensation of water vapor within the container causes a reduction in internal pressure sufficient to engage the lid to seal with the rim of the container; and

g) maintaining the container at the second temperature for a predetermined amount of time.

9. The process for cooking according to claim 8, wherein the step of heating to a first temperature uses a radiant heat source located below the container.

10. The process for cooking of claim 9 wherein the radiant heat source is an induction cooking base.

11. A process for cooking as claimed in claim 10, wherein the lid further comprises means for measuring temperature for measuring the temperature in the container, and the step of maintaining the container at the second temperature further comprises the steps of: the induction cooking base applies a series of spaced apart power pulses, wherein the maximum temperature rise caused by each pulse is measured with the means for measuring temperature, and the power of each subsequent pulse is determined by the measured change from the first temperature.

12. The process for cooking as claimed in claim 9, wherein the lid further comprises means for measuring temperature in the container,

wherein the step of heating the container to the first temperature at least until water is converted to a sufficient amount of water vapor to replace atmospheric constituents of the container is terminated based on a time calculated from the first time to reach the predetermined temperature.

13. The process for cooking according to claim 12, wherein the predetermined temperature is at least 94 degrees, and the time to terminate heating to the first temperature is the time to reach the first temperature, minus 60 seconds, and then divided by 2.