HEATER APPARATUS FOR SABBATH FOOD HEATING

Abstract

Apparatus for permissibly heating liquids during the Sabbath comprises a first vessel in which a liquid is received, a heat source for heating the liquid, and cooling apparatus to provide a predetermined regulated liquid temperature. In one embodiment, the apparatus comprises an additional vessel and a reheating vessel, and heating fluid is automatically flowable from the first vessel to the reheating vessel via the additional vessel to heat a liquid at a greater than threshold temperature. The additional vessel has cooling apparatus or an emptying arrangement, or a cooling apparatus is interposed between the additional vessel and the first vessel. In another embodiment, the heat source has a heating element, electrical insulation which is durable within surrounding liquid, and a temperature sensor for detecting heating element temperature or a conductivity sensor for detecting surrounding liquid electrical conductivity. A deactivation signal is transmittable to an electronic adaptor of the heating element.

Claims

1. A heater apparatus for permissibly heating a liquid during the Sabbath, comprising; a first vessel exposed to a heat source, within said first vessel a heating fluid is increased in temperature by said heat source; at least one additional vessel, one of which being settable in discontinuous liquid communication with said first vessel, wherein the heating fluid is automatically flowable from said first vessel to said one additional vessel during a period when the heating fluid is isolated from said first vessel after flowing to said one additional vessel; a reheating vessel which is heated by the heating fluid following discharge from said one additional vessel and which is configured to permissibly heat a liquid to a temperature greater than a threshold Sabbath-forbidden temperature; and means for delivering the heating fluid from said heating vessel to said first vessel, wherein said one additional vessel comprises a cooling apparatus for cooling at least one of a bottom and one or more walls of said one additional vessel; or means for emptying said one additional vessel following flow thereto of the heating fluid; or wherein said heater apparatus comprises a cooling apparatus interposed between said one additional vessel and said first vessel.

2. The heater apparatus according to claim 1, wherein the one additional vessel comprises the cooling apparatus and the means for emptying the one additional vessel following flow thereto of the heating fluid.

3. The heater apparatus according to claim 1, wherein the at least one additional vessel includes a second vessel that is settable in discontinuous liquid communication with, and having an interior at a temperature less than, the first vessel, and a third vessel that is settable in discontinuous liquid communication with, and having an interior at a temperature less than, the second vessel, wherein the reheating vessel is heated by the heating fluid discharged from the third vessel.

4. The heater apparatus according to claim 1, wherein the cooling apparatus is constituted by one or more means selected from the group consisting of passive cooling means, ventilation means, cooling ribs, a nozzle for externally spraying the one additional vessel with a cooling liquid, a mechanism driven by a motor for displacing the one additional vessel in order to be cooled, a pump for cyclically filling and emptying a tub in which the one additional vessel is located with a cooling liquid, refrigeration apparatus, one or more tubes extending to an external component and through which a gaseous or liquid coolant for cooling the heat fluid flows, and a selectively openable and closable valve through which the heating fluid is flowable.

5. The heater apparatus according to claim 4, wherein the mechanism is configured to immerse the one additional vessel in cooling liquid contained within the tub and to subsequently remove the one additional vessel from the tub.

6. The heater apparatus according to claim 1, wherein the means for emptying the one additional vessel following flow thereto of the heating fluid comprises a valve operatively connected to a conduit extending from an outlet of the one additional vessel and a controller in data communication with the valve, the controller operable to define a duration and frequency of each valve opening.

7. The heater apparatus according to claim 6, wherein the controller is additionally in data communication with a valve operatively connected to a conduit extending from the first vessel and with the means for delivering the heating fluid from the heating vessel to the first vessel, to facilitate cyclical flow of the heating fluid.

8. The heater apparatus according to claim 7, wherein the means for delivering the heating fluid from the food heating vessel to the first vessel comprises a recirculation conduit extending from the heating vessel to the first vessel and a pump operatively connected to said recirculation conduit.

9. The heater apparatus according to claim 7, wherein the heat source is a non-glowing heat source.

10. The heater apparatus according to claim 9, wherein the non-glowing heat source is an electrically powered heater having a heating element.

11. The heater apparatus according to claim 10, wherein the controller is additionally in data communication with a first temperature sensor for detecting an interior temperature of the first vessel or a second temperature sensor for detecting the temperature of the heating element of the non-glowing heater, wherein the controller is operable to command temporary deactivation of the heating element of the non-glowing heater in response to a predetermined high temperature detected by the first temperature sensor or the second temperature sensor.

12. The heater apparatus according to claim 8, further comprising a flow interruption unit for momentarily interrupting the flow of the heating fluid within the recirculation conduit extending from the heating vessel to the first vessel.

13. The heater apparatus according to claim 1, further comprising an isolation member for thermally isolating an upstream vessel from a downstream vessel during transfer of the heating fluid, the isolation member configured with a closed base formed with a closable inlet through which the heating fluid is receivable and with a closable annular outlet of a significantly smaller dimension than that of the base from which the heating fluid is dischargeable, wherein the isolation member is fillable with air exclusively following discharge of the heating fluid and closing of its inlet and outlet, and wherein air is captured in an interior of the isolation member when the interior is filled with the heating fluid.

14. The heater apparatus according to claim 1, wherein the first vessel further comprises cooling apparatus that is operable simultaneously, independently or in synchronization relative to the heat source, in order to achieve a predetermined first vessel interior temperature.

15. The heater apparatus according to claim 1, wherein the heating fluid is automatically flowable from the first vessel to the one additional vessel during a period when the heat source is deactivated.

16. A heater apparatus for permissibly heating liquids during the Sabbath, comprising; a first vessel within an interior of which is receivable a liquid; a heat source for heating the received liquid; and cooling apparatus that is operable simultaneously, independently or in synchronization relative to the heat source, in order to heat the received liquid at a predetermined regulated first vessel interior temperature.

17. The heater apparatus according to claim 16, further comprising a controller for defining operation of the heat source and the cooling apparatus, and a user interface for inputting the predetermined first vessel interior temperature to the controller prior to the onset of the Sabbath, wherein the controller is operable to disable the user interface when a Sabbath mode is initiated.

18. The heater apparatus according to claim 17, which is a water heater or an urn.

19. The heater apparatus according to claim 16, further comprising: at least one additional vessel, one of which being settable in discontinuous liquid communication with, and having an interior at a temperature less than, the first vessel, wherein the liquid is automatically flowable from the first vessel to said one additional vessel during a period when the liquid is isolated from the first vessel after flowing to said one additional vessel; a reheating vessel which is heated by the liquid following discharge from said one additional vessel and which is configured to permissibly heat liquid and solid foods to a temperature greater than a threshold Sabbath-forbidden temperature; and means for delivering the liquid from said heating vessel to the first vessel, wherein the liquid is at a temperature greater than the threshold Sabbath-forbidden temperature when discharged from the reheating vessel and is increased in temperature by the heat source after being introduced to the first vessel.

20. A non-glowing electric heater for permissible use on the Sabbath which is configured to transfer heat to a surrounding liquid, comprising an electric heating element made of thermally conductive material, a layer of electrical insulation applied to the heating element which is durable within the surrounding liquid, and a temperature sensor for detecting the temperature of the heating element or a conductivity sensor for detecting electrical conductivity of the surrounding liquid, wherein a detection signal producible by the temperature sensor or the conductivity sensor is transmittable to a controller which is operable to generate a deactivation signal that is subsequently transmittable to an electronic adaptor of the heating element, the deactivation signal being transmittable to the electronic adaptor if the detected temperature of the heating element is greater than a predetermined temperature that will cause the heating element to glow or if the detected electrical conductivity of the heating element is greater than a predetermined electrical conductivity.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0059] The invention may be more clearly understood upon reading of the following detailed description of non-limiting exemplary embodiments thereof, with reference to the following drawings, in which:

[0060] FIG. 1 is a schematic illustration, shown partially in perspective view, of an embodiment of a heater apparatus for permissibly heating liquid and solid food on the Sabbath, shown without its housing.

[0061] FIG. 2 is a cross sectional view of an embodiment of a heater that is suitable to be used in conjunction with the heater apparatus of FIG. 1.

[0062] FIGS. 3-5 are a schematic illustration of three embodiments, respectively, of a heater that is suitable to be used in conjunction with the heater apparatus of FIG. 1.

[0063] FIGS. 6-7 are a schematic illustration of two embodiments, respectively, of apparatus for cooling the second vessel used in conjunction with the heater apparatus of FIG. 1.

[0064] FIG. 8 is a schematic illustration of a control system used in conjunction with the heater apparatus of FIG. 1.

[0065] FIG. 8A is a schematic illustration of a compensation air delivery unit, according to an embodiment.

[0066] FIG. 8B is a schematic illustration of a compensation air delivery unit, according to another embodiment.

[0067] FIG. 9 is a method for transferring heating fluid from one vessel to another of the heater apparatus of FIG. 1.

[0068] FIG. 10 is a schematic illustration of an unconnected isolation member used in conjunction with the heater apparatus of FIG. 1, according to one embodiment.

[0069] FIG. 11 is a schematic illustration of the isolation member of FIG. 10, shown when connected to conduits and valves.

[0070] FIG. 11A is a schematic illustration of an embodiment of a flow interruption unit, shown when positioned between two vessels of the heater apparatus of FIG. 1.

[0071] FIG. 11B is a schematic illustration of another embodiment of a flow interruption unit, shown when positioned within a conduit of the heater apparatus of FIG. 1 and illustrating its flow interruption ability.

[0072] FIG. 11C is a plan view of two exemplary discs used in conjunction with the flow interruption unit of FIG. 11B.

[0073] FIGS. 11D-E are a schematic illustration of two arrangements, respectively, for ensuring operation of the flow interruption unit of FIG. 11B.

[0074] FIG. 11F is a schematic illustration of the isolation member of FIG. 10, shown with an additional flow interruption capability.

[0075] FIG. 12 is a schematic plan view of the food reheating vessel used in conjunction with the heater apparatus of FIG. 1 and of a surplus tank adjoining the food reheating vessel.

[0076] FIGS. 13-15 are a schematic illustration of three embodiments, respectively, of a mechanical thermostatic element.

[0077] FIGS. 16-17 are a schematic illustration of two implementations, respectively, of thermal regulation means, respectively, with use of a mechanical thermostatic element.

[0078] FIG. 18 is a schematic illustration, shown partially in perspective view, of another embodiment of a heater apparatus for permissibly heating liquid and solid food on the Sabbath, shown without its housing.

[0079] FIG. 19 is a schematic illustration, shown partially in perspective view, of another embodiment of a heater apparatus for permissibly heating liquid and solid food on the Sabbath, shown without its housing.

[0080] FIG. 20 is a schematic illustration of another embodiment of a heater apparatus for permissibly heating liquids on the Sabbath.

[0081] FIGS. 21-23 are a schematic illustration of three means, respectively, for emptying a second vessel.

[0082] FIGS. 24-27 are a schematic illustration of four embodiments, respectively, of cooling means that are interposed between two adjacent vessels.

DETAILED DESCRIPTION OF EMBODIMENTS

[0083] The invention may be more clearly understood upon reading of the following detailed description of non-limiting exemplary embodiments thereof, with reference to the drawings.

[0084] The following detailed description of embodiments of the invention refers to the accompanying drawings referred to above. Dimensions of components and features shown in the figures are chosen for convenience or clarity of presentation and are not necessarily shown to scale. Wherever possible, the same reference numbers will be used throughout the drawings and the following description to refer to the same and like parts.

[0085] Illustrative embodiments of the invention are described below. In the interest of clarity, not all features/components of an actual implementation are necessarily described.

[0086] FIG. 1 schematically illustrates an embodiment of a heater apparatus, generally indicated by numeral 100, for permissibly heating food on the Sabbath including solid food, soup, and liquid that generally has already been cooked. Heater apparatus 100 comprises first vessel 10, second vessel 20, third vessel 30, food reheating vessel 40, and pump 44 for delivering a heating fluid, after having previously flowed from first vessel 10, from food reheating vessel 40 to first vessel 10 via conduit 48. Vessel 20 is advantageously considered a second vessel by being configured with means ensuring that its interior will remain at a reduced temperature relative to first vessel 10.

[0087] Heater apparatus 100 is a monolithic apparatus that comprises the aforementioned components and a housing, as well a control system, as will be described hereinafter, although in some embodiments the heater apparatus may be configured without a the third vessel. The heater apparatus may be configured as a heating plate, or alternatively configured as an oven or a minibar or in other suitable ways.

[0088] It will be appreciated that heater apparatus 100 may not be monolithic, and the various vessels may be positioned in a distributed manner,

[0089] First vessel 10 is provided with a heater 12 and preferably with a first vessel thermal insulation layer 15. Heater 12 may be a non-glowing heater, such as an induction heater, an electrical heater, a microwave, steam, or another type of heater, or a combination thereof. As referred to herein, a non-glowing heater is a heater that does not emit, from an outer visible surface or from an interior surface, light caused by incandescing thermal radiation. Alternatively, heater 12 may be a glowing heater. The heater 12, which can be housed within the walls of first vessel 10 or within the first vessel, or both, is configured to heat a fluid therein (usually oil or water, but not limited). In one embodiment, the heating fluid is mixed by a stirrer 14, or mixed by other means, such as a rotating heater, to improve heat transfer and to prevent localized heating, thereby preventing overheating of the heater 12 to the point of emitting light in a dark environment, which may not in accordance with halacha. A first vessel cooling layer 17 (e.g. cooled by a refrigerator, a ventilator/fan, and so on) may be positioned outwardly to insulation layer 15. It will be appreciated that first vessel 10 may be provided without a stirrer.

[0090] After being heated by heater 12, the heating fluid exits the first vessel 10 via conduit 24 that extends to second vessel 20. The second vessel 20 receives the heated fluid from conduit 24, typically through cover 22 of the second vessel. Cover 22, which may be spring loaded, displaceable along a rail by a motor, or pivotally displaceable by a suitable mechanism can be momentarily opened automatically and then closed to retain the heat. The second vessel 20 may cooperate with a larger tub 50 that contains a volume of liquid. Tub 50 may be openable automatically to help the second vessel 20 to cool. The hot fluid cools somewhat by not being heated, and in some embodiments is also cooled by contact with the walls and bottom of the second vessel 20. It may be that in some fluids the natural cooling will be stronger than the cooling of the sides and bottom, but according to some opinions, halacha gives great importance to cooling by the sides and bottom.

[0091] In some embodiments, first vessel 10, second vessel 20, tub 50 and third vessel 30 are all uncovered.

[0092] In some embodiments, second vessel 20 comprises cooling apparatus 26, e.g. such as used in a refrigerator, for cooling the walls and bottom of second vessel 20. The cooling may be stopped before the fluid enters second vessel 20. In some embodiments, the heating fluid itself is not cooled proactively, and the sides and bottom of second vessel 20 are cooled only when there is no fluid in them. In some embodiments, the second vessel 20 (and/or third vessel 30) is cooled while the heating fluid is within those vessels.

[0093] The sides and bottom of second vessel 20 may be cooled to a desired temperature, for example cooled down to at least to 25 degrees Celsius according to a stringent halachic opinion.

[0094] The heating fluid may flow from first vessel 10 to second vessel 20 by gravity (in which case conduit 24 is downwardly extending and is provided with a valve 1A which may be controlled by one or more sensors) or by proactive means such as a pump (not shown). First vessel 10 may be configured with sloped bottom walls 16 leading to conduit 24. This same arrangement is applicable for delivering the heating fluid from second vessel 20 and third vessel 30 through valves 1B and 1C, respectively, to ensure that the corresponding vessel will be completely emptied and will be significantly cooled.

[0095] In some embodiments, second vessel 20 may have an insulation layer (not shown, but which can be similar to the insulation layer 15 of first vessel 10) positioned outwardly to the cooling apparatus 26. Furthermore, there may be an additional cooling apparatus (e.g., tub 50 or cooling layer 17) outwardly to this insulation layer.

[0096] In some embodiments, second vessel 20 may be positioned within a larger tub 50 that contains a volume of liquid, to help cool the sides and bottom of the second vessel 20, optionally between subsequent cycles of heating fluid flow through the apparatus, when there is no fluid in second vessel 20. In some embodiments, the cooling is done while the fluid is not in the vessels 20 and/or 30, and in some embodiments the cooling is done while the fluid is within the vessels. In some embodiments, the second vessel 20 is immersed in the larger tub 50 and is not permanently held therein. In some embodiments, the second vessel 20 is sprayed by water (or other liquid) to cause cooling. Alternatively, or in combination, a ventilator or fan 52 may be provided within the larger tub 50. Fan 50 may be provided without use of the tub. In some embodiments, the cover 22 of second vessel 20 can be openable/closable automatically. In some embodiments, the second vessel 20 could be placed in an automatically openable and closeable cooling room, in accordance with halacha.

[0097] In some embodiments the heating fluid is cooled while within vessel 20 (and/or vessel 30).

[0098] There are three embodiments by which the second vessel is able to be emptied so that its sides and/or bottom will be passively cooled. In all three, the second vessel is isolated from the heat source.

[0099] In the first embodiment, which is preferable, is that second vessel 20, after being completely emptied, is immediately filled partially or completely, and then the filling flow is stopped, whereupon the second vessel is once again emptied during an additional cycle. Alternatively, second vessel 20 is filled partially or completely after a sufficient waiting time following the emptying procedure to enabling cooling to a temperature level in accordance with the halachic opinion. The second vessel is able to be emptied by means of the opening of a valve and the delivery of the heating fluid through a conduit, the operation of a pump 63 and the delivery of the heating fluid through a conduit 27 as shown in FIG. 21, the opening of a hatch 28 or other type of closure to initiate the gravitational delivery of heating fluid from a second vessel 20B to an opening 33 of an underlying vessel 30B as shown in FIG. 22, the rotation of the second vessel 20C by means of a motor 29 and gear train 32 illustrated in FIG. 23, while the heater is stationary or is alternatively rotating as well as shown in FIG. 3, to facilitate discharge of the heating fluid through a dedicated opening 34 to an opening 33 of an adjacent vessel 30B as shown in FIG. 23, or a combination of two or more of these means.

[0100] In a second embodiment, less recommended from a halachic point of view, after being partially emptied, second vessel 20 is immediately filled partially or completely, and then the filling flow is stopped, whereupon the second vessel is once again partially emptied.

[0101] A third emptying embodiment is that the second vessel 20 is filled and emptied at the same time, which is the least recommended from a halachic point of view.

[0102] These three emptying embodiments are less recommended than the embodiment related to active cooling of the second vessel walls or the embodiment of waiting a time period for cooling.

[0103] In some embodiments, the apparatus includes a third vessel 30. If there is a third vessel 30, it receives the heating fluid from the second vessel 20. Third vessel 30 can be designed in the same manner as the second vessel 20, but is not necessarily identical thereto.

[0104] A reheating vessel 40 (receives the hot heating fluid from the third vessel 30. Reheating vessel 40 may be a food reheating vessel, and the term food reheating vessel includes an oven, a heating plate, a heating pot, and an urn for preparing for example coffee or tea. Alternatively, the reheating vessel may be a water heater, such as a residential heater for producing heated water for bathing purposes. The following description relates to a food reheating vessel, but it will be appreciated that any other vessel for heating a received solid or liquid by means of the circulating heating fluid is within the scope of the invention, including a reheating vessel, whether for first-time heating of the received solid or liquid or for reheating of the received solid or liquid.

[0105] The heating fluid is introduced via conduit 36 into the differently oriented walls of the food reheating vessel 40. Continuous conduit 36 is suitably bent to facilitate provision within a cavity formed within each wall of food reheating vessel 40 and also to assume the form of a convective-type heat exchanger 42, for example in serpentine fashion, whereby to heat food items including liquid food positioned within the interior of food reheating vessel 40. Alternatively, in lieu of being positioned within a cavity formed in a wall, heat exchanger 42 may be positioned interiorly to the walls of food reheating vessel 40, for example in abutting relation with the food reheating vessel walls or slightly spaced therefrom. Although not shown, a door of food reheating vessel 40 is provided to ensure sufficient heating of the introduced food item. The heating fluid may be releasably retained within heat exchanger 42 by valve 1D, and may be returned to first vessel 10 by proactive means, exemplified by a pump 44. Alternatively, the heating fluid may be gravitationally delivered to first vessel 10 or delivered thereto by means of a pressure differential generated by a pump provided upstream to food reheating vessel 40, such as upstream to third vessel 30. Thus it is understood that the heating fluid is cyclically reusable. The heating fluid is then reheated in first vessel 10, and the procedure continues.

[0106] There may be a halachic requirement that the heat exchanger 42 of the food reheating vessel 40, as well as the entire second vessel 20 and third vessel 30, be visible, for example transparent. There may also be a halachic requirement that food reheating vessel 40 have a ventilation opening.

[0107] As explained hereinabove, heating liquids by a fire-derived heat source to a temperature greater than the threshold Sabbath-forbidden temperature is forbidden on Shabbat even if the liquids are located at a distance from the heat source. Therefore it is in principle halachically forbidden for heat to be transferred through the sides and bottom of the first vessel 10 to the rest of the apparatus and also from the second vessel 20 to the rest of the apparatus. However there are opinions that allow such heat transfer. Most of these opinions are limited to the level of heat transferred, and some permit heat transfer from the second vessel to the third vessel.

[0108] For this purpose to limit heat transfer, it will be desirable to provide an insulation layer 15 on the sides and bottom of the first vessel 10 and of the second vessel 20 and to position first vessel 10 and second vessel 20 such that they will be located at a distant from the other components of the apparatus. If one wants to reduce the distance between the vessels, optionally, one can position a cooler (or cooling layer 17) at the sides and bottom outside the insulation layer 15. That is, there will be an insulation layer 15, and outside this insulation layer there will be a cooling layer 17, in accordance with halacha. In some embodiments, alternatively, or in combination, the vessels 10, 20, 30 and 40 are located at a distance one from the other where heat transfer is not an issue, according to halacha. The vessels 10, 20, 30, and vessel 40 can also be close one to another if it is halachically possible.

[0109] If there is a third vessel 30, it is possible that second vessel 20 has, like for the first vessel 10, an insulation layer 15 and cooling layer 17.

[0110] During those conditions for which the addition of an insulation layer to second vessel 20 slows down the cooling process such that the interior temperature of the second vessel is not sufficiently reduced relative to the first vessel, the distance between the first vessel and the second vessel may need to be increased, or alternatively an insulation layer or cooling layer for the second vessel may be dispensed with. Some halachic authorities may prohibit the use of an insulation layer for the second vessel since the cooling ability of the second vessel will be reduced.

[0111] In some embodiments, the apparatus includes a temperature sensor 13 positioned within first vessel 10. Temperature sensor 13 detects the interior temperature of first vessel 10, to ensure that heater 12 is operable to heat at an intensity less than a value that results in a glowing effect, or to ensure that the first vessel will not burn or explode, or will have a prohibited temperature, such as 100 C. In some embodiments, the control system ensures that the food reheating vessel 40 does not exceed a second threshold temperature, e.g. 85 C.

[0112] The food reheating vessel 40, such as a heating pot, heating plate/sink/stove, heating oven (with or without turbo), is heated using the heating fluid (for example edible oil that is introduced into heat exchanger 42).

[0113] In other embodiments, the food reheating vessel 40 can also be a kettle, an urn, a mini-bar device, or a water supply system for bathing. The food reheating vessel 40 can be a mini-bar or an oven that inside it will be a kettle, an urn, or a heating pot. The food reheating vessel 40 can be permanently connected to the water infrastructure (mains) or any other supply of liquid. The user receives the heated water or liquid, such as soup, via faucet 46.

[0114] A spinning device and a temperature sensor can be installed within the mini-bar. It is possible to attach the food reheating vessel 40 to permanent or temporary piping that leads to faucet 46.

[0115] In another embodiment, food reheating vessel is constituted by a liquid-tight container, or by apparatus that has an internal container; and instead of a pressurized liquid infrastructure, an additional container of heated liquid is provided above and in liquid communication with food reheating vessel 40.

[0116] Alternatively, the heater apparatus comprises one or more conduits through which heated water flows, extending from third vessel 30 or another heated water source that is permissibly heated on the Sabbath and penetrating through food reheating vessel 40, and not extending through an internal cavity. A food item may be heated by the one or more conduits, or may be retained in a liquid-tight container which is immersed in a body of liquid discharged from the conduits and stored in the interior of the food reheating vessel.

[0117] An embodiment of an electric heater 12A comprising a heating element 53 made of a single thermally conductive material, such as metallic material and usually a corrosion resistant material like stainless steel, and provided with a layer of electrical insulation 54, as schematically illustrated in FIG. 2, is adapted to transfer the generated heat to surrounding heating fluid HF well enough to ensure that heating element 53 will not glow. Electrical insulation 54, for example a water-resistant aerogel, is selected to have good thermal conductivity and to be durable within the surrounding liquid environment. The heater 12A may include a sealed temperature sensor 13 for detecting the temperature of heating element 53 to ensure that the heating element will not glow. Alternatively or additionally, heater 12A includes a sealed conductivity sensor 18 for detecting the electric conductivity of the heating fluid HF for purposes of safety. Conductivity sensor 18 is mounted on a wall of first vessel 10 by means of an elongated hanger 31 that comprises a sealed conductor, in order to be positioned in a central region of the accumulated heating fluid HF. A detection signal S1 producible by conductivity sensor 18 is transmitted through the internal conductor within hanger 31 to an electronic adaptor 57A, and from the adaptor through a conductor positioned within housing element 49A to a controller. Likewise a detection signal producible by temperature sensor 13 is transmitted to an electronic adaptor 57B, and from the adaptor through a conductor positioned within housing element 49B to the controller. A signal S2 reflective of a controller generated command to activate or deactivate heating element 53 is transmittable through the conductor, such as a wire, positioned within housing element 49B to electronic adaptor 57B in electrical communication with heating element 53.

[0118] An exemplary heating element 53 is a coiled resistance wire having a diameter of 2 cm that is physically connected to housing element 49B and electrically connected to electronic adaptor 57B while extending into the interior of first vessel 10. First vessel 10, having a length of 40 cm and a diameter of 10 cm, is filled with the heating fluid HF, which may be distilled water, after being discharged from the conduit extending from the food reheating vessel to the first vessel. The control system may be adapted to deactivate the heating element if temperature sensor 13 detects a heating element temperature of greater than a glowing temperature of 150 C. or if conductivity sensor 18 detects an electric conductivity of greater than a predetermined value that is indicative of a dangerous occurrence, such a degradation of electrical insulation 54 or of the heating fluid. Electric heater 12A may also comprise an additional temperature sensor, which may be mounted by a corresponding hanger 31, for detecting the temperature of the heating fluid, in order to regulate the interior first vessel temperature, to a value for example of between 95-98 C.

[0119] It will be appreciated that electrical insulation 54 may be dispensed with when the heating fluid is distilled water.

[0120] In some embodiments, a heater 12B shown in FIG. 3 is rotatable or a heater 12C shown in FIG. 4 is capable of producing alternating translational movement using a suitable arm assembly 58 having one or more links, by means of a motor 59 and a set of gears 61. Alternatively or additionally, the heating liquid in first vessel 10 can be circulated using a pump 56, within the interior of the first vessel or from the first vessel to the second vessel. Another suitable heater 12D shown in FIG. 5 is a motor 67 immersed in the heating fluid that generates heat when operating. It is also possible that the majority of the heat be generated by the frictional force that is produced during the movement of an arm 69 with respect to the heating fluid HF, while an additional amount of heat will be generated by motor heating and perhaps by proactive electric heating. The frictional force may prevent the heating fluid from emitting smoke if it is a combustible fluid such as oil and also prevent the heater 12D from increasing in heat to such a degree that it glows. It is also possible to add a heating element to the sides/bottom of the first vessel 10. A signal for controllably activating or deactivating any of the heaters may be transmitted by a relay.

[0121] As explained, there is a halachic advantage to generate non-glowing heating such as when a doubt arises, according to some opinions.

[0122] After the heating fluid is heated in the first vessel, the heating fluid undergoes a cooling process that will change its halachic status from a first vessel status to a second vessel status, and then from a second vessel status to a third vessel status (if the apparatus comprises a third vessel 30). By classifying the heating fluid with a second vessel status or a third vessel status, cold liquid foods, as well as other types of foods and liquids, are advantageously able to be permissibly heated to a temperature greater than the threshold Sabbath-forbidden temperature with the apparatus on Shabbat, or alternatively to room temperature according to some opinions.

[0123] The cooling process is as follows, to accommodate the requirements of halacha: the heating fluid is delivered by means of a pump, a pressure difference or gravity. It may be desirable from a halachic point of view to transfer the heating fluid through a conduit that is located above the second vessel 20 and not adjacent to it. There may also be a halachic advantage to add an insulation layer and a cooling layer to the conduit as described regarding the first vessel 10 and optionally to the second vessel 20. It is also desirable to install a valve that is operatively connected to the conduit located above second vessel 20 and that can be automatically closed between heating fluid transfer cycles.

[0124] The heating fluid flows from first vessel 10 into an empty second vessel 20 whose sides and bottom are automatically cooled or after having been cooled without intervention of the control system. In some embodiments, the sides and bottom of the second vessel 20 are cooled before the heating fluid flows thereinto. In other embodiments, the sides and bottom of the second vessel 20 are cooled while the heating fluid is within vessels 20 and 30. The second vessel 20 is required to be of a reasonable size which is defined according to the halacha as the size of a cooking pot or smaller than that and not a large size which is defined according to the halacha as a tub. It should be clarified that apparently the sides (and the bottom) should not be very cold but at a cool temperature (e.g., 25 degrees Celsius) or lukewarm. Apparently in halacha there is no requirement for cooling below 25 degrees Celsius.

[0125] Cooling apparatus 26 for cooling the sides and bottom of the second vessel 20 may include one or more of the following means: [0126] 1. Passive cooling means such as in conjunction with a control system that prevents influx of a heating fluid to a vessel for a predetermined period of time and therefore urges the vessel to be passively cooled. [0127] 2. Ventilation. [0128] 3. Cooling ribs, usually a metallic body with a large surface area. [0129] 4. A nozzle for externally spraying the second vessel 20, which is fed by a source of coolant or water. [0130] 5. A mechanism 47 schematically illustrated in FIG. 6, such as a four-bar linkage operable in conjunction with motor 59, raises second vessel 20 when empty and then immerses it into the cooling fluid contained within tub 50. Mechanism 47 also removes the cooled second vessel 20 from tub 50 in order to be subsequently filled with heating fluid transferred from first vessel 10. Mechanism 47 may also be used to transfer second vessel 20 to a dedicated cooling room. The displaceable second vessel 20 employs flexible conduits. [0131] 6. The cooling process can also be performed in conjunction with a stationary secondary vessel 20 located within tub 50 and with a pump 63 that cyclically fills and empties tub 50 for example via a conduit 71 in liquid communication with the interior of the latter, schematically illustrated in FIG. 7. Alternatively or additionally, cold or lukewarm air or gas bubbles or a cold or lukewarm coolant can be injected into tub 50. [0132] 7. The sides and/or bottom of the second vessel 20 are cooled using a cooling mechanism (e.g. refrigerator). In some embodiments, the sides and bottom of vessel 20 (and/or vessel 30) are cooled when the vessels are empty. In some embodiments, the heating fluid is cooled when it is received within vessel 20 (and/or vessel 30). In some embodiments, both the heating fluid is cooled and vessel container 20 (and/or vessel 30) is cooled. [0133] 8. Valve 1B at the exit of second vessel 20 is occluded after the second vessel 20 is filled with the heating fluid, for a duration of a few seconds or until the temperature is reduced, e.g. 5 C. Valve 1B is then reopened so that the heating fluid will flow to the third vessel 30 if the apparatus contains a third vessel. If the apparatus does not include a third vessel 30, the heating fluid flows to food reheating vessel 40.

[0134] In other embodiments, the cooling apparatus is interposed between two adjacent vessels. For example, a heat exchanger 272 shown in FIG. 24 or an evaporator 274 shown in FIG. 25 serves to cool the heating fluid discharged from first vessel 10 and introduced into second vessel 20 with a coolant. Alternatively, the heating fluid is cooled by a blower 276 shown in FIG. 26 or a radiator 277 shown in FIG. 27, which is interposed between second vessel 20 and third vessel 30.

[0135] Instead of some or all of the cooling means listed above, the heating fluid can be introduced into and be directed to exit second vessel 20 periodically, for example by means of an external heat exchanger or evaporator. Automatic fluid cycles may be provided by which (a) the second vessel 20 is filled (or partially filled), (b) the fluid flow leading to the second vessel is terminated when the second vessel is filled (or partially filled) with the desired amount of fluid, and (c) only then is second vessel 20 emptied (or partially emptied) into third vessel 30 or into food reheating vessel 40 (if there is no third vessel 30).

[0136] The third vessel 30, if provided, is configured similarly as the second vessel 20. The third vessel 30 receives heating fluid from the second vessel 20 and transfers the heating fluid to the food reheating vessel 40. When the second vessel 20 transfers heating fluid to the third vessel 30, heat transfer through the walls of the second vessel 20 or the first vessel 10 to the third vessel 30 or to reheating vessel 40 is limited or altogether prevented.

[0137] After exiting third vessel 30, if provided, the heating fluid is introduced into the food reheating vessel 40 and circulates within heat exchanger 42 thereof.

[0138] As the heating fluid heats the food reheating vessel 40 and the food item positioned within its interior, the heating fluid cools passively as a result of the heat transfer. The heating fluid is also cooled passively as it is delivered to the first vessel 10. The cycle is then repeated over and over again automatically.

[0139] For enhanced heat transfer, the conduits of any or all of first vessel 10, second vessel 20, third vessel 30 and food reheating vessel 40 through which the heating fluid flows may be configured with fins (not shown). In some embodiments, first vessel 10, second vessel 20, third vessel 30 and food reheating vessel 40 may be provided with an internal grille (not shown) for improving the heat transfer to the heating fluid.

[0140] FIG. 8 schematically illustrates an automatic control system 110, according to one embodiment. Control system 110 facilitates cyclical flow of the heating fluid from first vessel 10 to second vessel 20, from second vessel 20 to third vessel 30, from third vessel 30 to food reheating vessel 40, and from food reheating vessel 40 to first vessel 10. When the heater apparatus is configured without a third vessel, the heating fluid flows cyclically from second vessel 20 to food reheating vessel 40. Cyclical flow means interrupted flow that flows at set intervals without being influenced by external factors, although the flow rate may be dependent upon temperature according to some halachic opinions.

[0141] Control system 110 comprises a controller 106, e.g. a PID controller, for controlling the operation of various components, including non-glowing heater 12, stirrer 14, equipment 109 such as a refrigerator or fan for generating cooling air adapted to flow within cooling layer 17 (FIG. 1), and valve 1A that are associated with first vessel 10. Controller 106, which may be housed within a wall of the heater apparatus, is in data communication with these components via a wired connection extending through a wall of the heater apparatus as well as with a temperature sensor 13A for detecting the interior temperature of first vessel 10, a temperature sensor 13B for detecting the temperature of the heating element of heater 12, and a temperature sensor 13C for detecting the temperature of the room in which the heater apparatus is located. The heating element of heater 12 and possibly stirrer 14 will be temporarily deactivated in response to a predetermined high temperature detected by any of temperature sensors 13A-C. A high temperature is detected by temperature sensor 13C, for example, is indicative of a high heat transfer rate from first vessel 10 to the room.

[0142] Controller 106 is additionally in data communication with temperature sensor 13D for detecting the interior temperature of second vessel 20, cover actuator 23 for actuating displacement of the second vessel cover upon transfer of the heating fluid to the second vessel, cooling apparatus 26 for cooling the walls and bottom of the second vessel, tub actuator 54 for actuating a controlled displacement of a closure of the tub, valve 1B for partially or completely emptying the second vessel, valve 1C for partially or completely emptying the third vessel, valve 1D for partially or completely emptying the food reheating vessel, and pump 44 for delivering the heating fluid exiting the heat exchanger of food reheating vessel 40 to the interior of first vessel 10.

[0143] Control system 110 may be operable to limit operation of the heater or of the cooling apparatus during any of the following events: i. a high temperature event of the heating element of greater than approximately 150 C. that is liable to result in the heater to glow or otherwise emit light, ii. a predetermined high temperature event that is liable to result in burning of the heating fluid or in damage to the first vessel, iii. a regulation event during which the heating element operates in accordance with a predetermined duty cycle, for example is activated every 2 minutes for a constant operation of 5 seconds, until the heating fluid achieves a predetermined maximum temperature, iv. a regulation event by which the heater operates with a constant heat intensity and cooling apparatus of the first vessel operates in accordance with a predetermined duty cycle until the heating fluid achieves a predetermined maximum temperature, v. a high temperature event influenced by the heater that causes the first vessel cooling layer or an external wall or insulation layer of the second vessel, whether filled with heating fluid or empty, not to exceed the threshold Sabbath-forbidden temperature or another temperature value, vi. a low temperature event that causes the sides and bottom of the second vessel and/or the third vessel to reach a predetermined low temperature.

[0144] The heating fluid flows in a closed cycle throughout the heater apparatus. To compensate for subatmospheric pressure that may result following the flow of heating fluid from one vessel to another, each of the first, second and third vessels may be provided with a supply of air that is isolated from the corresponding vessel by an isolation valve 83A-C. A pressure sensor 86A-C in data communication with the controller is provided within the interior of the corresponding vessel, and transmits a signal to controller 106 upon detecting subatmospheric pressure, whereupon the controller commands opening of the corresponding isolation valve to increase the pressure to atmospheric pressure. The corresponding isolation valve may be commanded to open and to reduce pressure if an excessive pressure is detected. Alternatively, the controller may command opening of the corresponding isolation valve in response to a predetermined high liquid level within the vessel that is detected by a level switch or other types of a level sensor. Termination of introduction of heating fluid into the vessel may be synchronized with the detection of a predetermined high liquid level.

[0145] Compensation for the generation of subatmospheric pressure air in a corresponding vessel following discharge of heating fluid therefrom may be by means of a balloon-based compensation unit 115 schematically illustrated in FIG. 8A. Balloon 111 is secured to a portion of a wall 113 of the vessel, e.g. the second vessel, surrounding a dedicated aperture 112 through which compensation air is flowable. Balloon 111 is normally inflated with compensation air, and the compensation air flows into the vessel interior to deflate the balloon when subatmospheric pressure air is generated within the vessel interior. Upon introduction of additional heating fluid into the vessel, a significant amount of the compensation air is displaced in return into the interior of balloon 111. Compensation unit 115 may also comprise a pressure relief valve 117 mounted on wall 113 or on any other desired region of the vessel, for releasing air from the vessel interior during an excessive pressure buildup event, and also a drainage port 119 through which moisture that condenses from the compensation air is able to be discharged. The condensation discharged from drainage port 119 may be combined with the heating fluid when the heating fluid is water.

[0146] Another embodiment of a compensation unit 125 is schematically illustrated in FIG. 8B. In this embodiment, a container 121 presupplied via port 102 with compensation air, for example air pressurized at a pressure of 1.1 atmospheres, is common to all vessels, for example to vessels 10, 20 and 30. Container 121 is subdivided into corresponding chambers 123 that each is capable of directing pressurized air to a specific vessel via a dedicated aperture 112 formed in the wall of that vessel. Despite the uninhibited passageway through aperture 112, flow of heating fluid through a corresponding chamber 123 into container 121, after being introduced into the specific vessel, is able to be prevented by controlling the duration of the upstream valve opening. The volume of heating fluid that is permitted to flow into the specific vessel in response to the upstream valve opening is therefore less than the available volume of heating fluid that can accumulate within the specific vessel until rising through the aperture into the corresponding chamber.

[0147] When the pressure in a vessel interior drops, the pressurized air flows to the vessel having a reduced pressure, to compensate for the reduced pressure. Compensation unit 125 also comprises cooling apparatus 26, a pressure relief valve 117 and a compressor 104, within each chamber 123 or alternatively which may be common to all chambers. Cooling apparatus 26 is operated in such a way to maintain a compensation air temperature of no more than 39 C., in order to cool the walls of an empty vessel to a temperature less than the threshold Sabbath-forbidden temperature. A drainage port 119 and optionally a check valve 97 through which moisture that condenses from the compensation air is able to be discharged is provided for each chamber 123. A discharge conduit 108 extends from the corresponding drainage port 119 to a conduit 36 through which the heating fluid flows, and a pump 107 in data communication with the controller is adapted to deliver accumulated drainage through discharge conduit 108. Drainage pump 107 may be activated in response to a predetermined level of drainage as detected by level sensor 103. Alternatively, pump 107 may deliver accumulated drainage to first vessel 10 if a temperature sensor located in a corresponding discharge conduit 108 detected a drainage temperature of greater than the threshold Sabbath-forbidden temperature. It will be appreciated that a pump 107 and a discharge conduit 108 may also be provided for compensation unit 115 of FIG. 8A.

[0148] Although the aperture of the vessel through which compensation air is introducible is shown to be in a central region of the vessel for purposes of clarity, it will be appreciated that in actuality the aperture is located at or near the top of the corresponding vessel, to minimize interference with any accumulated heating fluid.

[0149] The regeneration of the pressure of compensation air may be performed at the end of the Sabbath, following a pressure check.

[0150] An exemplary flow cycle of the heating fluid through the heater apparatus is as follows, in response to command signals transmitted by controller 106: [0151] i. after the heating fluid underwent a cooling process in the second vessel and acquired a second vessel status, valve 1B at the exit of the second vessel is opened for a duration of 28 seconds at the commencement of a heating cycle to facilitate complete emptying of the second vessel and transfer of the heating fluid to the interior of the third vessel, [0152] ii. cooling apparatus for cooling the heating fluid within the third vessel is operated for a duration of 3 minutes, [0153] iii. for a duration of 2 seconds, valve 1B at the exit of the second vessel is closed and a pump between the second and third vessels, if provided, is deactivated, [0154] iv. the cooling apparatus for cooling the walls and bottom of the second vessel is operated for 45 seconds, until an elapsed time of 75 seconds from the commencement of the heating cycle, to ensure that the temperature of the walls and bottom of the second vessel will be reduced to a temperature of 39 C., for example, [0155] v. for a duration of 28 seconds, valve 1A at the exit of the first vessel is opened and a pump between the first and second vessels, if provided, is activated, to facilitate transfer of the heating fluid from the first vessel to the second vessel, [0156] vi. for a duration of 2 seconds, valve 1A is closed and the pump between the first and second vessels, if provided, is deactivated, [0157] vii. at an elapsed time of 105 seconds from the commencement of the heating cycle, an operation to cool the heating fluid within the second vessel is initiated while the cooling operation to cool the heating fluid within the third vessel continues simultaneously, [0158] viii. at an elapsed time of 210 seconds from the commencement of the heating cycle after the temperature of the heating fluid within the third vessel has been reduced by 5 C., the cooling operation to cool the heating fluid within the third vessel is ended, valve 1C at the exit of the third vessel is opened and pump 44 is operated for a duration of 28 seconds, so that the heating fluid will flow from the third vessel to the heat exchanger of the food reheating vessel at a temperature of 75 C. to suitably heat the food item positioned within the interior of the food reheating vessel, and additionally the heating fluid previously located within the heat exchanger of the food reheating vessel will be transferred to the first vessel, [0159] ix. for a duration of 2 seconds, valve 1C is closed and pump 44 is deactivated, [0160] x. at an elapsed time of 240 seconds from the commencement of the heating cycle, the cooling apparatus for cooling the walls and bottom of the third vessel is operated for 45 seconds and, simultaneously, the heater within the first vessel is operated with an intensity of 3000 W for a duration of 45 seconds, by thermostatic control for example, until the heating fluid achieves a temperature of 95 C., and [0161] xi. at an elapsed time of 285 seconds from the commencement of the heating cycle, after the walls of the third vessel have cooled to a temperature of 38.5 C. and the heating fluid within the second vessel has been cooled for approximately 3 minutes and its temperature has been reduced by a temperature of 5 C. to 90 C., the heating fluid is suitable to be delivered from the second vessel to the third vessel.

[0162] The cooling apparatus for cooling the walls and bottom of a vessel may include a blower. The cooling apparatus for cooling the heating fluid within a vessel may include a mixer.

[0163] The flow rate of the heating fluid and the duration and frequency of each valve opening are preferably constant, being set before Shabbat, since an increased flow rate of the heating fluid or an increased duration and frequency of a valve opening will result in a prohibited increase in temperature of the heating fluid during Shabbat. According to some halachic authorities, the flow rate of the heating fluid and the duration and frequency of each valve opening may be adjustable in response to the detection of one or more temperature sensors.

[0164] As described above, it is forbidden to turn the heater apparatus or any component thereof on or off on Shabbat or to press electrical switches (or a touch screen) on Shabbat, and therefore the electrical apparatus should be set before Shabbat. The temperature sensors are adapted to control the level of heating of the first vessel 10, second vessel 20 and third vessel 30, as well as the level of cooling or duration of heating and cooling, such as in conjunction with heating or cooling apparatus. The temperature sensors can also control the transfer rates of the heating fluid as well as the frequency of the heating cycles and the cooling cycles. The temperature sensors can also determine that the vessels will not be filled completely in each cycle. The temperature sensors can also control the means of rotation for various parts of the apparatus and in each component of the apparatus.

[0165] The function of the flow cycles is to provide sufficient heat in the food reheating vessel 40 to heat a food item and maintain the temperature. The food item may be able to be heated in some embodiments even if additional heating fluid is not introduced to the food reheating vessel during a given period of time. A portion of the heating fluid is adapted to be discharged from food reheating vessel 40 via faucet 46 in order to be consumed (or otherwise used).

[0166] A supply of water from the municipal water infrastructure (mains) may be connected to food reheating vessel 40 and heated thereby. Alternatively, edible liquid such as soup is introducible into the food reheating vessel 40 through a dedicated port formed in a cover or wall of the food reheating vessel 40, provided that an introduction mechanism is built for this implementation from a halachic point of view.

[0167] Sensors in data communication with the control system for detecting depletion of the edible liquid may cause automatic termination of the operation of the heater apparatus if it is foreseen that a dangerous consequence is liable to result.

[0168] FIG. 9 illustrates a method according to one embodiment for transferring heating fluid from one vessel to another of the heater apparatus while avoiding simultaneous contact by a stream of heating fluid with heated first and second vessels. By avoiding simultaneous contact with two heated vessels by the heating fluid, the second vessel need not be classified with the halachic status of a first vessel. This method also prevents the third vessel or the food reheating vessel to be classified with the halachic status of a first or second vessel.

[0169] The second and third vessels are completely emptied in step 114 before the heating fluid is heated in step 116 by the heater in the first vessel. In this fashion, a volume of air in the second vessel isolates the third vessel from the first vessel. Thus when the heating fluid is subsequently delivered to the second vessel in step 118, heat is advantageously not transferred to another volume of heating fluid via valve 1B.

[0170] Likewise the third vessel and the heat exchanger of the food reheating vessel are completely emptied in step 120 before the heating fluid is transferred from the second vessel to the third vessel in step 122. Also, the first vessel and second vessel are completely emptied and the heater is deactivated in step 124 before the heating fluid is transferred to the first vessel in step 126.

[0171] FIGS. 10-11 illustrate one embodiment of an isolation member 131 for isolating one vessel from the other during the transfer of heating fluid. Isolation member 131 has a conical periphery 132 that is delimited by an upper closed base 137, such that the heating fluid is received through an inlet 134 formed in base 137 and is discharged through a lower annular outlet 136 of a significantly smaller dimension than that of base 137. The height of periphery 132 is sufficient to define a space within which a desired volume of heating fluid to be transferred is receivable. An isolation valve 133 in data communication with the controller is operatively connected to inlet 134.

[0172] Isolation member 131 is positioned in secured juxtaposition with, for example, valve 1A downstream to the exit of the first vessel and with a portion of conduit 24 leading to the second vessel. Outlet 136 is adapted to abut and to be in liquid communication with valve 1A, and isolation valve 133 is adapted to abut and to be in liquid communication with an upstream portion of conduit 24. When isolation valve 133 is closed, the upstream heating fluid is prevented from flowing into isolation member 131, resulting in the isolation member being filled with air exclusively. The air contained within isolation member 131 serves to thermally isolate the confined upstream heating fluid from the downstream vessel, so that the downstream vessel will not have to be classified with the same halachic status as the upstream heating fluid. When isolation valve 133 is subsequently opened and valve 1A is closed, the heating fluid is urged to flow to the interior of isolation member 131, become increasingly cooled, and then flow to the downstream vessel after valve 1A is opened at a later time. The air within the interior of isolation member 131 becomes compressed while the heating fluid flows to the downstream vessel. Due to the presence of compressed air, at least a residual portion of the heating fluid always remains within the isolation member interior, and therefore limits the degree to which the isolation member is able to become cooled.

[0173] Isolation member 131 may be configured without cooling apparatus, and the captured air within its interior serves to isolate the downstream vessel from the upstream vessel.

[0174] Alternatively, isolation member 131 may be provided with cooling apparatus 26 that will ensure that the captured air will be sufficiently cooled to a temperature below the threshold Sabbath-forbidden temperature or any other temperature and the downstream vessel will be classified with a downstream vessel status even according to stringent halachic opinions. Cooling apparatus 26 is preferably cooled as the same time as cooling apparatus 26 of the first vessel, and may be configured similarly as or differently than cooling apparatus 26.

[0175] The isolation member may assume other configurations, such as a bell shape and a dome shape, to facilitate alternating air isolation and heating fluid holding operations. During a heating fluid holding operation, the heating fluid may occupy approximately 10% of the isolation member interior. A similar isolation member is preferably provided at the inlet to each vessel.

[0176] FIG. 11A schematically illustrates a flow interruption unit 145 whereby the flow of heating fluid from food reheating vessel 40 to first vessel 10 is periodically or intermittently interrupted, to avoid having the food reheating vessel classified with the halachic status of a first vessel. Alternatively, a flow interruption unit 145 may be provided between first vessel 10 and second vessel 20, or between second vessel 20 and third vessel 30.

[0177] One embodiment of a flow interruption unit 145 is a quickly opening and closing control valve that is operatively connected to the conduit extending between food reheating vessel 40 and first vessel 10, the flow of heating fluid of course being interrupted such in the form of a spray when the control valve is closed, to produce a volume of captured air. Other flow interruption units are also in the scope of the invention.

[0178] A flow interruption unit 145A, according to another embodiment schematically illustrated in FIG. 11B, comprises two or more apertured discs 138 and 141 that are fitted in conduit extending from the 48 food reheating vessel to the first vessel and that may each be differently apertured. At least one of discs 138 and 141 is rotated whereby corresponding apertures of discs 138 and 141 are at times aligned to allow flow F of heating fluid therethrough and at times are misaligned to interrupt the flow therethrough. At any given time, there is no continuum of flow between the food reheating vessel and the first vessel due to the influence of flow interruption unit 145A and particularly of the various apertures. As a result of the presence of the apertures, air is captured upstream to flow interruption unit 145A. To ensure flow between discs 138 and 141, even though it is interrupted, the two discs are preferably in abutting relation with each other while being made of an abrasion resistant material such as a polymeric material, or alternatively are in close proximity to each other, for example positioned by a separation of no greater than 0.3 mm.

[0179] An exemplary disc 138 is shown in FIG. 11C to be formed with six apertures 139, four of which circumferentially separated by the same radius R1 from the center 142 and two of which separated by a different radius R2 from the center. An exemplary disc 141 that is formed with two apertures 139 is also shown which are separated by radii R1 and R2 from the center 142, respectively. Alternatively, the same aperture arrangement provided in disc 138 may also be provided in disc 141; however, when the two discs rotate at a different rate or one is eccentrically rotated, the corresponding apertures are periodically misaligned to interrupt the flow.

[0180] Discs 138 and 141 may be fitted in conduit 48 by means of an interiorly positioned sleeve 129, as shown in FIG. 11D. While bottom disc 138 is fixed to sleeve 129, upper disc 141 is caused to rotate by shaft 154 that is rotatably mounted in annular mounts 157a-b which are fixedly connected by corresponding braces 127 to the sleeve. Shaft 154 in turn is driven by a gear train 159 or other type of transmission that is connected to motor 162 positioned externally to conduit 48 and that passes via a corresponding aperture through the wall of conduit 48 and of sleeve 129.

[0181] Alternatively as shown in FIG. 11E, discs 138 and 141 may be mounted in a dedicated hollow housing 168 to which conduit 48 is fed and from which an additional conduit 172 extends, whereby the heating fluid is delivered from food reheating vessel 40 to first vessel 10 via conduit 48, housing 168 and additional conduit 172. While bottom disc 138 is fixed to housing 168, upper disc 141 is caused to rotate by shaft 154 that is rotatably mounted in upper wall 184 and lower wall 186 of housing 168. Shaft 154 in turn is driven by a gear train 159 or other type of transmission that is connected to motor 162 positioned externally to housing 168 and that passes through a cavity formed in upper housing wall 184. Upper wall 184 and lower wall 186 of housing 168 are formed with dedicated apertures through the heating fluid is able to flow.

[0182] Flow interruption unit 145A may be positioned externally to the base 137 of isolation member 131 as shown in FIG. 11F, to provide both isolating means and flow interrupting means. Alternatively, flow interruption unit 145A may be positioned internally within isolation member 131.

[0183] FIG. 12 schematically illustrates a surplus tank 144 for holding heating fluid not introduced into heat exchanger 42 of food reheating vessel 40. Surplus tank 144 may be positioned within the interior of food reheating vessel 40, or alternatively, exteriorly thereto, and in liquid communication therewith by valves 146 and 147 that are in data communication with the controller. Three-way valve 146 is normally set to direct the heating fluid flowing through conduit 36 to heat exchanger 42. However, if it is anticipated that the available volume within heat exchanger 42 will not suffice, valve 146 will be reset to momentarily direct the heating fluid via conduit 143 to the interior of surplus tank 144. When the flow conditions return to normal, valve 146 is first completely closed and valve 147 in liquid communication with heat exchanger 42 and conduit 149 is opened, to allow the surplus liquid to flow from tank 144 via port 148 and conduit 149 to heat exchanger 42 when pump 44 is operated. Afterwards, valve 147 is closed and valve 146 is once again reset to direct the heating fluid via conduit 143 to heat exchanger 42. A pump 187 may be used to suction surplus liquid from tank 144 to conduit 149, and another pump 189 may be used to assist in the circulation of heating fluid within heat exchanger 42.

[0184] A slow and constant flow of surplus liquid may circulate from surplus tank 144 to heat exchanger 42 in order to be mixed with the heating fluid flowing through heat exchanger 42, to produce a slow and constant flow of heating fluid that is discharged from food reheating vessel 40 for use in a subsequent heating cycle. By use of surplus tank 144, pump 44 adapted to deliver heating fluid from food reheating vessel 40 to first vessel 10 is able to operate substantially continuously and a food item is able to be heated substantially constantly by the heat exchanger since deactivation cycles are rendered unnecessary. To ensure that food reheating vessel 40 will remain with

[0185] a status of a third vessel even though the heating fluid flows continuously therethrough, a flow interruption unit may be added to conduit 149 or to heat exchanger 42 downstream to valve 147, or an isolation member 131 (FIG. 11) may be added to conduit 36 upstream to valve 146. Alternatively, the heater in the first vessel may be deactivated when transferring the heating fluid from the first vessel to the second vessel. Other means to reduce the stringency of food reheating vessel 40, in addition or in lieu of these previously mentioned means, is by adding a fourth vessel through which the heating fluid circulates that is interposed between the third vessel and the food reheating vessel. The fourth vessel overcomes a stringent opinion that if a heating element operates during flow of a heating fluid, the second vessel will be considered a first vessel, the third vessel will be considered as a second vessel. Accordingly, the fourth vessel will be considered as a third vessel. Alternatively, the heating element can be deactivated before the flow of the heating fluid.

[0186] According to some halachic authorities, temperature regulation during the Sabbath by means of electronic temperature sensors is prohibited due to a change in heat intensity or frequency that is liable to be initiated by a user's activity. There is an added stringency of using an electronically controlled heating element relative to a pump or electronically controlled cooling apparatus, for example, according to these halachic authorities. To comply with the opinion of these halachic authorities, the heater apparatus may be configured without temperature sensors and all settings will be defined before Shabbat. Alternatively, temperature regulation during the Sabbath may be carried out by means of a mechanical thermostatic element (MTE).

[0187] One mechanical thermostatic element is a bimetallic strip 152 schematically illustrated in FIG. 13 that is made of two connected metals 153a-b having different coefficients of thermal expansion. Alternatively, strip 152 may be made of two other connected materials having different coefficients of thermal expansion. Strip 152 is used to convert a temperature change into mechanical displacement by physically expanding or contracting in response to a sensed temperature, and is configured to assume for example the illustrated convex shape when a predetermined temperature is reached, whereupon an actuator 156 of an interface element 158, such as a valve element, button or a closure, which may be spring loaded, is pressed. Following actuation of interface element 158, the opening state, whether opened, closed, or partially closed, of interface element 158 is changed, and a cooling medium associated with cooling equipment 163 is either introduced through an intervening cavity or is blocked, the term blocked also including a situation for which operation of the interface element is disabled. Actuator 156 may be a mechanical, hydraulic, pneumatic or electrical actuator, for example a clutch or a motor.

[0188] Other apparatus that may be operated by means of interface element 158 and the mechanical thermostatic element include a continuously operating motor, a hydraulic motor, a pneumatic motor, and a clutch based mechanism.

[0189] Another mechanical thermostatic element is a wax thermostatic element 161 schematically illustrated in FIG. 14 that is configured with a solid wax pellet that is received with a sealed chamber 164. In response to a predetermined sensed temperature, the wax having a specific composition melts and expands together with sealed chamber 164, such that the expanded chamber or an extension thereof, or an element in driving relation thereof, presses actuator 156 of interface element 158. Alternatively, a different solid material may be used that is adapted to melt at a specific temperature.

[0190] A reactive force may be applied to a mechanical thermostatic element by means of a member that causes resistance, such as a piston mechanism, a spring based mechanism, fluid resistance in conjunction with a hollow expandable element, and a gravity responsive element.

[0191] Another mechanical thermostatic element is a gas or liquid-filled probe 167 schematically illustrated in FIG. 15 that is in liquid communication via a capillary line 166 with an inner cavity of a secured expandable member 169 such as a membrane, diaphragm, balloon and a piston-based unit that is operatively coupled to actuator 156 of interface element 158. Member 169 expands in response to an increased temperature sensed by probe 167, to induce the actuated action of interface element 158.

[0192] One implementation of a MTE for temperature regulation is in conjunction with a thermal storage unit (TSU) 171, as schematically illustrated in FIG. 16. A TSU 171 may be a pressure vessel that is preloaded or periodically loaded via closable port 173 with a temperature-regulating fluid, such as a gas or a pressurized liquid having a temperature significantly higher than the interior temperature of first vessel 10 being heated by a heater 12A that is constantly operating or operating for a predetermined duration, or alternatively comprises heating means 176 for maintaining the high temperature of the temperature-regulating fluid whose temperature or intensity is not adjustable or its adjustment means is disabled on the Sabbath, for example following selection of a Sabbath control mode. In one embodiment, TSU 171 may be filled with a solid or granular medium such as sand through which the temperature-regulating fluid is able to circulate. A heat exchanger 177 is configured with a first passageway 178 for the flow therethrough of the temperature-regulating fluid from TSU 171 and with a second passageway 179 for the flow therethrough, for example in counterflow fashion, of the heating fluid from first vessel 10 and in heat exchanger relation with first passageway 178 enables the temperature-regulating fluid to transfer heat to the heating fluid and to thereby increase the temperature of the latter.

[0193] When the interior temperature of the heating fluid within first vessel 10 is lowered below a threshold temperature, MTE 151A and 151B, which are exposed to the temperature of the first vessel and may be any of the MTE types described hereinabove, undergo a predefined change in shape. Accordingly, MTE 151A initiates actuation of interface element 158A by which the temperature-regulating fluid is urged to flow from TSU 171 into first passageway 178. For the purposes of this embodiment, interface element 158A may be a pump, valve or other type of fluid delivery device. The changed-shape MTE 151B is adapted to actuate interface element 158B and to adjust its opening or operating state, to enable the heating fluid to flow through second passageway 179 and to be brought in heat exchange relation with the temperature-regulating fluid. The temperature-regulating fluid is discharged from first passageway 178 into TSU 171, preferably via check valve 182, and the heating fluid is discharged from second passageway 179 into first vessel 10. Once the interior temperature of the heating fluid within first vessel 10 is raised above the threshold temperature, MTE 151A and 151B return to their original shape or size and discontinue their actuation of interface elements 158A and 158B, respectively, thereby terminating the flow of the temperature-regulating fluid into the first passageway and the flow of the heating fluid into the second passageway.

[0194] A pump may be used to circulate the temperature-regulating fluid within the TSU 171 or within heat exchanger 177.

[0195] To ensure that the temperature of the temperature-regulating fluid will not be excessive and cause heater 12A to glow, TSU 171 may be provided with cooling equipment 174 to ensure that the temperature of the temperature-regulating fluid will be less than a predetermined threshold. A MTE 151C is exposed to the interior temperature of TSU 171, and is adapted to actuate cooling equipment 174 when the interior temperature of TSU 171 rises above another threshold temperature, causing a reduction in temperature. Cooling equipment 174 may be similar to any cooling apparatus described herein with respect to first vessel 10, and may also include a radiator that is cooled by an actuated fan.

[0196] TSU 171 may be implemented for heating water for use in a pool or an urn.

[0197] In other embodiments, first vessel 10 may be equipped without a heater and the heating fluid may be heated by heat exchanger 177 exclusively.

[0198] MTE 151A-C may be in physical contact with the fluid to which they are exposed, or alternatively may be housed in a cavity that is contiguous and in heat exchange relation with the fluid to which they are exposed.

[0199] The other components of the heater apparatus such as valves 1A-D may be cyclically controlled by controller 106, as similarly described in relation to FIG. 8.

[0200] Another implementation of a MTE for temperature regulation is for displacing an overheated first vessel 10 in conjunction with mechanism 47, as schematically illustrated in FIG. 17. In this embodiment, constantly operating heater 12A is normally positioned externally to, and in contact with, first vessel 10. When the temperature of an outer surface of the first vessel rises above a predetermined threshold, a MTE 151D in heat exchanger relation with the outer surface of the first vessel undergoes a predefined change in shape and presses actuator 156 of motor 59 that is configured to drive mechanism 47. After being driven by motor 59, mechanism 47 raises or otherwise displaces first vessel 10 in such a way so as to be significantly separated from heater 12A and to undergo a reduction in temperature. Motor 59 is configured to drive mechanism 47 in reverse until first vessel 10 once again contacts heater 12A, when the temperature of the outer surface of the first vessel is lowered below the predetermined threshold. Alternatively or additionally, a MTE 151D is adapted to undergo a predefined change in shape to actuate cooling equipment that cools heater 12A. The conduit extending from first vessel 10 to another vessel such as the second vessel and that includes at least a valve is sufficiently flexible to accommodate the displacements to which the first vessel is anticipated to be subjected.

[0201] It will be appreciated that a mechanical thermostatic element may be deployed with respect to any component of the heater apparatus, including for example the second vessel, the third vessel or the food reheating vessel.

[0202] FIG. 18 schematically illustrates heater apparatus 180 for permissibly heating food on the Sabbath, according to another embodiment. Heater apparatus 180 comprising first vessel 10A, second vessel 20A, third vessel 30A and food reheating vessel 40A is identical to heater apparatus 100 of FIG. 1, and additionally comprises one or more of the following cooling units, or other types of apparatus: [0203] a. Additional cooling equipment for first vessel 10A that is embodied by a fan 60 and/or a nozzle 62 for generating a coolant spray, in addition to or instead of the equipment used to cool the cooling layer 17 provided with first vessel 10 of FIG. 1. [0204] b. A cooling gas injection element 66 injects a cooling gas such as air, for example at room temperature, into the second vessel 20A or the third vessel 30A. [0205] c. Heat is removed from the heating fluid from the second vessel 20A or third vessel 30A by means of a liquid cooling member 68, such as a plate heat exchanger or water block configured with a metal having a high thermal conductivity that is formed with passages through which the heating fluid and a cooling liquid flow. A portion of the heating fluid is diverted by valve 181, for example at the exit of second vessel 20A, through conduit 73 that passes through liquid cooling member 68 and extends to conduit 24 at the inlet of the same vessel after the heating fluid is reduced in temperature. [0206] d. A mixer 72 is provided for the liquid inside second vessel 20A or third vessel 30A, to help it cool. [0207] e. Some of the heating fluid exiting food reheating vessel 40A via conduit 48 is diverted to second vessel 20A (and/or third vessel 30A), using a three-way valve 70, to facilitate mixing of the heating liquid in the second or third vessel with the liquid exiting food reheating vessel 40A, in order to reduce the heating fluid temperature. The remaining undiverted portion of the heating fluid exiting food reheating vessel 40A is directed to first vessel 10A. [0208] f. A source of a salt water type heating fluid, which has an advantage over regular water because salt water produces less steam than water without salt, and the use of a vaporized heating fluid in a second vessel is more stringent than an unvaporized heating fluid according to some halachic authorities. One halachic opinion is that using salt water is preferable relative to an oil heating fluid. If heater 12A (FIG. 2) lacks electrical insulation, the heating fluid has to be without electrical conductivity, such as distilled water. [0209] g. First vessel 10A comprises an altitude detector 74 to determine whether a heating fluid that is not water will reach the boiling point of water or whether water will boil at less than 100 C., when located at a high altitude. Altitude detector 74 may comprise a barometric pressure based altimeter, a GPS receiver for measuring elevation, or a combination thereof. The controller receives a signal representative of the detected altitude, and is therefore able to determine the local boiling point, controlling operation of the heater so as to avoid having the heating fluid achieve the local boiling point. [0210] h. According to some opinions, there may be a halachic prohibition for the side of the food reheating vessel 40A to be closed. Thus, in some embodiments, the door is replaced by an air curtain 64. Apparatus for generating air curtain 64 may be in data communication with the controller. There can be more than one air curtain, e.g. from the top or sides. The air curtain is preferably recessed, e.g. several centimeters from the opening that is left by removing the door.

[0211] Some or all of these components of heater apparatus 180 may be controlled by controller 106 (FIG. 8) together with other components of control system 110. Alternatively, some or all of these components of heater apparatus 180 may be actuated in response to a predefined change in shape by a mechanical thermostatic element.

[0212] FIG. 19 schematically illustrates heater apparatus 220 for permissibly heating food on the Sabbath, according to another embodiment. Heater apparatus 220 comprises first vessel 10A, a radiator 80 for receiving the heating fluid discharged from first vessel 10A, and food reheating vessel 40A for receiving the heating fluid discharged from radiator 80. Heater apparatus 220 lacks a third vessel.

[0213] Radiator 80 is configured with a plurality of tubes 82, generally finned, through which the heating fluid flows in order to be cooled after being discharged from first vessel 10A via conduit 24. Tubes 82 may be air cooled, such as by means of a fan positioned in close proximity thereto. Alternatively, tubes 82 may be cooled by a coolant flowing through conduits that are in heat exchanger relation therewith, or may also be cooled by a heat pump. The cooled heating fluid is discharged from radiator 80 through conduit 86 and flows through heat exchanger 42 of food reheating vessel 40A.

[0214] The controller commands the emptying of heating fluid from radiator 80 after being transferred thereto from first vessel 10A, such as by closing valve 1A and opening valve 88 operatively connected to conduit 86 following a sufficiently long period during which the heating fluid circulates within tubes 82 and is cooled. Thus radiator 80 is considered to be a second vessel as it is isolated from first vessel 10A, particularly when an isolation member 131 (FIG. 11) is employed.

[0215] As the heating fluid received within tubes 82 is cooled by, for example, at least 5 C., it is advantageously considered to have a halachic status of a second vessel, and can therefore permissibly heat a food item received within the interior of food reheating vessel 40A.

[0216] Some or all of these components of heater apparatus 220 may be controlled by controller 106 (FIG. 8) together with other components of control system 110. Alternatively, some or all of these components of heater apparatus 220 may be actuated in response to a predefined change in shape by a mechanical thermostatic element.

[0217] FIG. 20 schematically illustrates heater apparatus 240 for permissibly heating liquids on the Sabbath, according to another embodiment, which comprises first vessel 10A, and particularly a heater 242 according to any configuration described herein including enhancement by a TSU as shown in FIG. 16, and cooling apparatus 246 according to any configuration described herein, but without a second vessel or a food reheating vessel. For example, heater 242 or cooling apparatus 246 may be operated or temperature regulated in conjunction with mechanism 47 and MTED 151D as shown in FIG. 17, or with respect to any implementation of a MTED described herein.

[0218] A user interface (UI) 247, such as a set of finger pressable buttons for making selective electrical contact, a GUI or a touchscreen, is used to set a predetermined temperature of the heating fluid within the interior of first vessel 10A prior to the onset of the Sabbath. When a Sabbath mode is initiated, user interface 247 is preferably disabled to avoid an inadvertent interfacing action, while heater 242 and cooling apparatus 246 operate simultaneously, independently or in synchronization, for example in conjunction with a controller, in order to achieve the predetermined temperature. The heating fluid is introduced to the interior of first vessel 10A via inlet port 251 and is dischargeable therefrom via outlet port 253.

[0219] The first vessel may also comprise tubes of a heat exchanger or an evaporator within which a coolant circulated to cool the heating fluid that extend outwardly from the heater apparatus or are in embedded within the walls of the heater apparatus that are positioned inwardly to the insulation layer.

[0220] The cooling apparatus 246 may be influenced by the MTED. Alternatively, the cooling apparatus 246 may operate continuously, and a valve actuated by the MTED is interposed between the first vessel and the cooling apparatus. Alternatively, a pump may be provided that circulates the heating fluid through the cooling apparatus of the first vessel, or that circulates the coolant including a liquid or gas the tubes locate within the first vessel. The pump may operate continuously or may be influenced by the MTED. If there is no pump, the first vessel is preferably located bellow the cooling apparatus due to the rising heat.

[0221] It will be appreciated for any use of a MTED described herein, an automatically controlled element may be used as a replacement.

[0222] Heater apparatus 240 having an electrical connection may be a water heater generally adapted for residential use, for heating water in a pool, or an urn for dispensing hot water. Regarding an urn, outlet port 253 may be a spigot and inlet port 251 through which water is manually introducible may be accessed upon removal of the lid, for example threadedly.

[0223] A desired water temperature provided by heater apparatus 240 may be set prior to the onset of the Sabbath, and may advantageously be permissibly regulated by the control system during the course of the Sabbath. The ability to be temperature regulated is in contrast to prior art Sabbath compliant urns whose heating element is constantly operated, resulting in an unforeseeable water temperature that depends on the ambient air temperature. When heater apparatus 240 is a water heater, the water temperature can be regulated for the benefit of elderly users for purposes of bathing, for example.

[0224] Some or all of these components of heater apparatus 240 may be controlled by controller 106 (FIG. 8) together with other components of control system 110. Alternatively, some or all of these components of heater apparatus 240 may be actuated in response to a predefined change in shape by a mechanical thermostatic element.

[0225] The heater apparatus according to any embodiment described herein may be implemented for other use having halachic related importance, such as related to bathing and dietary laws, whereby a heated second or third vessel is a valid substitute for a prior art first vessel configured with a heat source.

[0226] While some embodiments of the invention have been described by way of illustration, it will be apparent that the invention can be carried out with many modifications, variations and adaptations, and with the use of numerous equivalents or alternative solutions that are within the scope of persons skilled in the art, without exceeding the scope of the claims.