Patent Grant
7488919
The present invention relates to a warming apparatus. The present invention relates more particularly to an electronically controlled warming apparatus, and more particularly to an electronically controlled warming drawer.
Warmer drawers of conventional design are typically configured as closed boxes, having a construction of single walled or a double walled with insulation or air in between and a sliding drawer of some sort to open up the interior of the box. Such conventional warmer drawers often have front door(s) fixed in a vertical plane and heating of the interior has been by a single cal rod (i.e. sheathed heating element) that will radiate heat, thus warming the interior of the box.
The conventional warmer drawers use mechanical controls to control and maintain the food temperatures. These mechanical controls tend to have an undesirable degree of inaccuracy and have a tendency to dry out food, overheat, have large swings in temperature ranges from a desired set point, which results in over and under shoots.
The sensors used in conventional warmer drawers to detect the temperature within the drawer have been mostly capillary tubes. Expanding gases, as temperature increases or decreases, transfers force or relaxes force to a mechanical switch, causing the switch to close or open, thus supplying current to or turning off current to the cal rod (i.e. sheathed heating element). The response time for these types of controls tends to be slow and also contributes to (or exacerbates) over and under shoots in temperature within the warmer drawer.
These sensors and the design of operation generally causes slow response for temperature corrections, thus causing temperatures to over shoot and under shoot. These resulting temperature ranges and swings, from the on to off cycling, have a tendency to drive moisture out of foods, hold more moisture in the chamber, and/or over cook food(s). Also, when set for the proofing temperature, bread will not proof correctly (i.e. not to rise properly) at lower temperatures, and at the higher temperatures bread tends to develop large pockets of air.
Conventional warmer drawer design typically locate the heating elements on the inside top or bottom of the chamber (e.g. box, cavity, compartment). A cal rod (sheathed heating element) used in varying patterns, provides radiant heat. This radiant heat often produces hot spots when placing an object like a pan or plate in close proximity to the cal rod. Temperature hot spots are understood to be due to the radiant heat source being strongest (hottest) near the cal rod and decreasing in temperature as distance increases away from the cal rod. Accordingly, such conventional warmer drawer designs provide undesirable temperature level variation within the chamber. These temperatures variations tend to cause problems for controlling and maintaining the food temperatures, such as stratifying or layering of air temperatures which causes problems for food holding. Also, start-up times to get warm temperatures in the chamber can be long due in part to the cal rod design. Such long start-up times are undesirable and prevent an operator from just turning the warmer drawer on and placing food in the chamber. Accordingly, such conventional warmer drawers have undesirably long start-up or pre-heat times necessary in order to stabilize the temperature inside the cavity at a desired level, otherwise food is held at lower temperatures, which can cool foods or encourage spoilage. Also as the temperature and heat cycles, large temperature over and under shoots tend to be created causing food to dry out, and loss of accurate temperature control for longer periods, and poor food holding capability.
Conventional warmer drawer designs typically use knobs and slides to set and control mechanical switches for setting the desired temperature. However, these mechanical switches are generally known to be inaccurate in their setting and repeatability. The mechanical switches often have problems maintaining a set point and can permit swings in temperature within the chamber partly due to the design of the warmer drawer and method of heating, but also due to the inaccuracy of the mechanical switches themselves. Mechanical control switches have a known condition of hysteresis, which contributes to their inaccuracy in the controllability to obtain a set temperature point or repeat a function. This inaccuracy can be demonstrated (for example) by turning the control to the right and stopping at a set point versus turning the same mechanical control past the set point and then turning the control to the left and stopping at the set point. Both actions end with the same set point selected but the resulting temperature will usually be different. The inaccuracy of the mechanical switches tends to increase the effects of having temperature over and under shoots and contributes to the large temperature swings inside the chamber of the warmer drawer. This inaccuracy is believed to contribute greatly to the gradiant temperature problems found in present warmer drawers with the chamber having problems with temperature over shoot and under shoot.
The mechanical switches typically used in conventional warmer drawers are also susceptible to the adverse effects of surrounding environmental influences. For example, if subjected to cold temperatures, mechanical switches could work slowly, crack, become hard to turn, fail to operate, their lubrication can harden causing the operation not to function, cause switch chatter resulting in premature failure or reduced life of product, and cause other detrimental issues to a user. By further way of example, if subjected to hot temperatures mechanical switches could experience slow operation from drying out of lubrication, crack, discolor, become hard to turn, fail to operate, experience switch chatter and/or premature failure, and cause other detrimental issues to a user when trying to set the controls or operate the warmer drawer. Further, if mechanical switches and/or controls are subject to outdoor environments like rain, snow, sun, UV, or the like, then special protected control switches are usually required to prevent intrusion of these environmental contaminants that may otherwise cause premature failure or reduced product life. Special sealed controls used in such environments tends to increase the price of a warmer drawer. Accordingly, mechanical switches and controls when used outdoors in conventional warmer drawers tend to create additional drawbacks such as needing to be covered or otherwise protected from the environment, which tends to increase the cost for such products.
Typical mechanical switches and controls for conventional warmer drawers tend to have poor repeatability and generally do not provide the user the ability to repeatably return to a certain preset position (e.g. reuse of same settings, etc.) or reliably establish the same temperature when using the conventional warmer drawer in a series of different operations. For example, a user generally cannot set a proper temperature on one day and then return the next day to the same set point if the controls were moved during an intervening period (as is often necessary). Temperature swings of as much as 30 degrees or more are believed to occur in such instances.
The conventional warmer drawers are also subject to other deficiencies. For example, conventional warmer drawers are typically constructed for use in permanent (e.g. built-in, etc.) installations, such as to cabinetry, an appliance, or some other generally stationary structure. Examples include conventional warmer drawers built into a cabinet under a product such as a cook top, oven, or some other appliance like a slide-in stove to a drop-in range. In other applications, conventional warmer drawers can be used in a location independently, but are still typically built into a cabinet or some structural frame. This limits the mobility of the warmer drawer from being used in a variety of desirable locations. Accordingly, it would be desirable to provide a warmer drawer capable of being used as a freestanding unit, as a mobile unit, used under a cabinet (e.g. suspended), or in areas with or without the support from a structural frame.
Therefore a need exists for a warmer drawer in which more accurate and controlled heating of objects such as food is accomplished. There also exists the need for an accurate method of controlling the operations and settings of the warmer drawer. There also exists a need for the controls of the warmer drawer to be less susceptible to environmental influences. There also exists a need for a display device to permit a user to be able to view/see the operation, temperature indication(s), set point functions, and view of the contents of the chamber. There also exists a need for a warmer drawer capable of remote control operation. There is a further need to accurately apply and control heat within the chamber of the warming drawer. There is also needed for a warmer drawer such that it can be used in any desirable location to suit the particular needs of a user.
Accordingly, it would be desirable to provide a warming apparatus, such as a warmer drawer having electronic control, with any one or more of these or other advantageous features.
According to an embodiment, the present invention relates to a warmer drawer with an enclosure defining a chamber and having an opening. A movable portion is reciprocally movable within the chamber and a heating element provides heat to the chamber. A user interface receives an input from a user for controlling operation of the warmer drawer and at least one sensor provides a signal representative of a temperature in the chamber. An electronic control system interfaces with the heating element, and the user interface and the sensor and operates to control a supply of electrical power in a regulated manner to the heating element during operation of the warmer drawer, so that an object contained within the chamber is maintained at a pre-determined temperature.
According to another embodiment, the present invention also relates to a warming apparatus having an enclosure defining a chamber to receive objects and a heating device communicating with the chamber. A detection system with at least one sensor is provided to detect a temperature within the chamber. A user interface is provided for interaction with a user and operates to establish a desired temperature for the chamber. An electronic control system receives a signal from the sensor and the user interface to control the operation of the heating device to attain and maintain the desired temperature within the chamber.
According to a further embodiment, the present invention also relates to an electronically controlled warmer drawer that includes an enclosure having sides and a top and a bottom defining a chamber. A movable holder is coupled to the enclosure for movement between a retracted position to support objects within the chamber and an extended position external to the chamber to permit access to the objects by a user. A heating system operates to heat the chamber and a ventilation system operates to move air through the chamber. A user interface with multiple inputs controls a temperature within the chamber. A detection system detects a condition within the chamber and provide a signal representative of the condition. A display device displays information for perception by a user, and an electronic control system interfaces with the heating system and the ventilation system and the user interface and the detection system and the display device so the objects can be maintained at a desired temperature.
FIGS. 35 and 36A-36E are a schematic views of a movable display device and use interface according to an exemplary embodiment.
According to the illustrated embodiments, there is disclosed a warming apparatus (shown and described as a warmer drawer 12) controlled by an electronic control system to provide improved chamber temperature control, rapid heat-up, improved temperature set point repeatability and minimal temperature variation from a desired set point. The electronic control system of the warmer drawer is shown to interface with (among others) a detection system having various sensors (e.g. temperature, humidity, infrared, scanners, electrical current, microwave, etc.), a heating element(s), a ventilation system, a display device and a user interface to enable a wide variety of desirable and advantageous features. For example, the warmer drawer is shown as a modular device that is adaptable for use in a wide variety of locations and environments and with other appliances, fixtures or structures. The warmer drawer (when in use) is intended to use a continuously adjustable amount of power in a heating element to maintain a more precise control of temperature within the chamber (rather than conventional and less-precise “on-off” type devices, however, the electronic control system could be configured for use with conventional heating elements and sensors to reduce swings in temperature). The warmer drawer is also shown to include a ventilation system that may be actuated by various technologies to regulate the flow of air, heat and/or moisture throughout the chamber. The ventilation system may include a heating element and/or fan within the chamber, or a heating element and/or fan may be located remotely from the warming drawer and fluidly interconnected by a suitable passage or duct. The warmer drawer is also shown to include a display device configured to display information to a user related to operation, temperature, functions, times or other control parameters for the warmer drawer. The display device is configured to display text (stationary or scrolling) and graphic images or illustrations. The warmer drawer is also shown to include a user interface (locally controlled and/or remote-controlled) to facilitate operation (e.g. selection of inputs, setting changes, start, stop, hold, etc.) of the warmer device by a user. The warmer drawer is further shown to have a temperature-controlled internal chamber that is accessible by access through a door or panel (e.g. “reach-in” etc.) or by a movable portion (e.g. movable holder, extendable portion tray, panel, drawer, etc. configured to hold objects within the temperature controlled environment of the chamber) that is extendable from, and retractable to, the chamber (in a manually-operated or power-operated manner). The warmer drawer is also capable of use in attaining and maintaining a desired temperature(s) for a wide variety of objects including foods (and other non-food items (e.g. plates, towels, etc.). The warming drawer as shown and described may also be constructed as a multi-use drawer (e.g. for warming, drying, baking, boiling, steaming, roasting, etc. and also for cooling). The ability to combine a warmer drawer with an appliance such as range, a mini-oven, a toaster oven, a steam drawer, a baking drawer, a boiling oven, a broiling oven, and a microwave oven thus reducing the space required and the ability to multi task from one appliance. This ability to combine a warmer drawer with an appliance or an appliance combined with a warmer drawer provides the user with advantages in space, reduce energy usage, and time savings. Accordingly, all such features are within the scope of this disclosure. However, this description is not intended to be limiting and any variations of the subject matter shown and described may be made by those of ordinary skill in the art and are intended to be within the scope of this disclosure.
Referring to the Figures,
The warmer drawer 12 is also shown to include a heating system 20. The heating system is shown to include one or more heating elements 22 within the chamber 16 (shown for example as one heating element 22 within the chamber 16 in
The ability to better regulate the electrical current to the heating elements 22, 24 such that the power output can be increased or reduced with improved accuracy, and similarly increasing or decreasing the heat output to the chamber 16 with greater accuracy is achievable with electronic control. An electronic control system 40 for a warmer drawer 12 is shown, for example, in
According to an exemplary embodiment, the electronic control system 40 includes a positive temperature coefficient of resistance (PTC) current/voltage controller for controlling the heat and power requirements and providing rapid response during start-up. This PTC controller allows current to the heating element(s) 22, 24 and as temperature gets close to the upper limit, the PTC device limits the current to the heating element, stopping the rapid rate of heat/temperature increase in the chamber 16, thus preventing overshoot. PTC thermistors (thermally sensitive resistors) are solid state, electronic devices, which detect thermal environmental changes for use in temperature measurement, control and compensation circuitry and exhibit an increase in electrical resistance when subjected to an increase in body temperature. PTC devices remain in their low resistance state at all temperatures below the temperature corresponding to the desired set point. When the temperature corresponding to the desired set point is reached or exceeded, the PTC exhibits a rapid increase in resistance thereby quickly limiting current to the heating element circuitry to minimize temperature overshoot. Once the temperature within the chamber decreases to a normal operating level, the device resets to its low resistance state providing full load current to the heating element. The dramatic rise in resistance of a PTC Thermistor at the transition temperature tends to makes it an attractive candidate for current limiting applications. For currents below the limiting current, the power being generated in the unit is not sufficient to heat the PTC to its transition temperatures. However, when abnormally high fault currents flow, the resistance of the PTC increases at such a rapid rate that any increase in power dissipation results in a reduction in current. These devices have a resistance temperature characteristic that exhibits a very small negative temperature coefficient until the device reaches a critical temperature for the upper limit or set point of the warmer drawer, which is referred to as the “curie,” switch, or transition temperature. As this critical temperature is approached, the PTC device begins to exhibit a rising positive temperature coefficient of resistance as well as a large increase in resistance. This resistance change can be as much as several orders of magnitude within a temperature span of a few degrees. Thus as the cavity chamber temperature increases from an ambient temperature, the PTC electronic device increases in surface temperature reducing the ability to dissipate heat which results in an increase in resistance resulting in reducing the current to the heating element. This increase in resistance and reducing current also slows down the heat up when coming to the set point. These devices also do not completely stop the flow of current to the heating element, but rather, limit the current. Thus providing and maintaining a steady temperature by substantially eliminating on/off swings that other conventional warmer drawers provide. This design also provides users with cost savings; since the undesirable “on/off cycling” with its corresponding overshoots and undershoots is avoided, the full current draw of the heating element is also avoided and the warming drawer uses only the required current for start-up heating and maintaining the desired temperature. According to other embodiments, the electronic control system includes any one or more of a micro controller(s), micro technology, integrated circuits, drivers and microprocessors that may be mounted on one or more printed circuit boards, to provide the desired functionality of interfacing with the heating elements, the ventilation system, the sensors, the display device and the user interface.
The illustrated power board and control board show one type of electronic control (see
Such embodiment providing and electronic control system as described above is an improvement over prior art methods of cycling power on and off in an attempt to control the heat. With the improved method one can determine the needed heat load for the chamber and supply only that amount of power/heat. This also can prevent temperature over shoots by quick warm ups and when almost reaching the fixed set point, limit the amount of energy heat (current) when reaching the fixed set point. The ability to better regulate the electrical current to the heating elements such that the power output can be regulated will improve accuracy, and similarly increase or decrease the heat output to the chamber with greater accuracy. This innovation reduces the user's cost to operate this product. The electronics and sensors can determine the needed heat load for the chamber and supply only that amount of heat to the chamber.
The warmer drawer 12 also includes a display device 60 (see
The warming drawer 12 also includes a user interface 70 (see
Electronic controls can be placed on any surface to accommodate any design or for matching or simulating the look of other products that may be associated with the warmer drawer. The touch control keypad(s) 72 of the user interface 70 and display(s) 62 of the display device 60 can be placed on the front of a warmer drawer 12 to provide the user with “instant viewing” of the operations and functions without having to open up the warmer drawer. Touch control panels 72 can be made of metal, plastic or glass to suit a particular application. The use of micro controller(s), integrated circuits and drivers, PC board(s), processor, and power, and other electronics can be used in the electronic control system 40 to interface with the touch pads 72 of the user interface 70 to control operation of the warmer drawer 12. Any size from a small to a large warmer drawer can be fitted for use with a touch type control pad (e.g. piezo, capacitance, resistance, etc.). Further, any size from a small to a large warmer drawer can be fitted for use with an induction touch control pad. The design of the electronics can be unique or matched to the other looks, aesthetics, appearance or decor on adjacent or cooperating appliances or structures. The overall size, design, look and feel of a warmer drawer can be matched to the size, design, look and feel of any appliance or structure.
According to an exemplary embodiment, the touch control panels 72 of the user interface 70 can be remotely controlled having the electronics or a portion of the electronics located not on the product, but in a different location not on the warmer drawer (see
The structures for the display device 60 and the user interface 70 control functions could be mounted to the fixed faceplate or the movable face/door of a warmer drawer (see
According to another exemplary embodiment, the display device 60 and/or user interface 70 may be placed on any desired surface of the warmer drawer or associated structure (e.g. to accommodate any design for matching or simulating the look of other products the appliance may be paired with, or to protect the components from damage, or exposure to adverse environments, etc.). By way of example, the display device 60 and user interface 70 may integrated (shown for example as an integrated display/interface 79; however, the display and interface may be kept as separate devices) and arranged to be “hidden” from normal view by the closing of a sliding panel (which may be spring-biased) or by integrating the display/interface 79 with a rotating panel or L-shaped plate (shown for example as a rotating drum 76 in
According to another embodiment shown for example in
According to the embodiment illustrated in
According to another embodiment the warmer drawer 12 may be configured as a multi-use—warmer drawer that combines a mini-oven, warmer drawer/broiling cavity, multi-use warmer drawer/steam oven, multi-use warmer drawer/baking oven and multi-use warmer drawer/microwave oven in any suitable combination. Combining the warmer drawer with other heating or cooking products can reduce space used in a kitchen (institutional, commercial, residential, etc.). Using these warmer drawer/multi-use drawers can save electricity and heat energy due to their small size. A large portion of the energy consumed in cooking applications is often associated with preparation of small amounts of food. Having to heat up a large oven takes time and is more expensive than using a mini-oven/warmer drawer. This mini-oven/warmer drawer could take the place of a toaster oven saving counter space. When combined with a broiling element within the chamber 16, additional capabilities for cooking and providing temperature holding capabilities may be realized that are not presently found in conventional products. Another embodiment provides a “multiple use” warmer drawer/mini-oven/broiling cavity. It is readily apparent from the above description that combining the warmer drawer 12 as described herein with other cooking equipment can be a great benefit to a home kitchen or other food preparation or maintenance location. It also readily apparent from the disclosure that any desirable appliance with a warmer drawer.
According to another embodiment, a warmer drawer 12 or multi-use drawer can be configured as a modular unit having the ability to be adapted to “fit” into a range or other appliance(s) without being built-in (see
According to another embodiment the warmer drawer 12 is adaptable as a warmer drawer/multi-use drawer shown for example as a mobile pedestal heated chamber with drawers, slides, or doors for warming, cooking and holding food and non-food applications (see
A mobile heated warmer drawer/multi-use drawer can also be installed into a mobile island or cart 87 to be used for cooking and holding food (and for non-food applications as well) (see
According to another embodiment, a warmer drawer/multi-use drawer 12 is provided that is configured to be controlled by the electronic control system 40 and equipped with an AC or DC electronic temperature sensor 52 located inside the chamber 16 such that the temperature of the chamber 16 can be detected accurately. Controlled by electronics and equipped with an AC or DC electronic temperature sensor 52 provides control and operation response, to sense temperatures in the chamber 16 and then the electronic control system 40 provides a suitable output to control the heating element(s) 22, 24 functions for on/off or regulated power operation. Any electronic sensor used for detecting temperature, resistance, or power using such devices as thermos/thermal detection device(s) for the control of the chamber temperature can be used with the electronic system in a warmer drawer/multi-use drawer. The heating element is electronically connected to a temperature-sensing device and is AC or DC powered in accordance with requirements for the warmer drawer installation or use location. With user selected settings (e.g. through the user interface 70) or preset (factory or otherwise) settings of the electronic control system 40, the signals associated with maintaining the desired temperature(s) within the chamber 16 are sensed and sent by the temperature-sensing device 52 within a predetermined desired range of operating temperature(s) or set point(s). The sensor 52 can be mounted on the electronic board or it can be attached by itself to any wall or location in which detection of the temperature can be made. The ability to better detect the temperature within the chamber improves the response time to the changes inside the chamber and improves the accuracy of the actual temperature in the chamber when compared to the desired set point. This quick response and control reduces the effects of overshoot and undershoot. Any electronic, mechanical, or electromechanical sensor can be used for detecting temperature, resistance, or power for detection and control of the temperature in the chamber with the use of electronics. Any electronic, mechanical, or electromechanical, AC or DC sensor can be used for detecting and control of temperature, resistance, or power for better control of the chamber temperature. Such sensing or detecting devices, which can be used include, but are not limited to temperature sensors, thermostats, thermal, temperature controls, thermal protectors, thermal cutoffs, thermal switch, thermocouples, adjustable thermostats, printed circuit board thermostats, hermetically sealed, time delay relay, bulb and capillary, cold controls, electronic controls, bimetallic, pressure switches, creep action thermostats, resistance temperature detectors, controllers, manual reset, automatic reset, disc thermostat, snap action switch, negative temperature coefficient of resistance thermistors, power positive temperature coefficient of resistance thermistors that can be controlled by electronics, or other suitable device. The sensing devices, along with the electronic control system is intended to provide better temperature control of objects within the chamber and ultimately, improved user satisfaction.
According to another embodiment, sensing technology such as scanner detection technology may be used to directly sense the temperature of an object in the chamber for providing a signal to the electronic control system for controlling the power and heat from the heating element and/or controlling operation of the ventilation system 30. A warmer drawer 12 can have the ability to detect objects placed inside the chamber 16 and then set temperature(s) for maintaining required temperature. For example, in a warmer drawer with item detection on a target surface, an IR sensor 56 collects a small amount of energy (usually 0.0001 watt) radiated from the target, generates an electrical signal that is amplified by a precision amplifier and converted into voltage output. A CPU digitizes the signal by an Analog-to-Digital Converter, an Arithmetic Unit solves a temperature equation based on Planck's Radiation Law, compensates for the ambient temperature and emissivity resulting in a temperature reading within a fraction of a second after user places the item in the field. Using this technology one can measure the temperature of an item or cover the complete surface from a five (5) meter distance as long as the Field of View is filled by the target. Also, many IR sensors measure in the 8 um to 15 um wavelength band where the atmosphere is almost totally transparent. IR sensors can operate in complete darkness. In the 8 um to 15 um wavelength band, IR can penetrate PE film (for example: a plastic trash bag or saran wrap). The IR thermometer sensor 56 can detect the presence of the object.
IR sensing can measure objects that move, rotate, or vibrate (e.g., web process or any moving process). They are understood not to damage or contaminate the surface of the object of interest. They measure the temperature of the actual product being used in a warmer drawer and not some of the other parts of the surfaces. Thermal conductivity of the object being measured such as glass, metal, wood or even very thin objects does not present a problem, as is the case with certain other sensors. Response time is typically in the millisecond range, which gives the user more information per time period. The IR detector system can be used for heat/fire and/or distance in the warmer drawer. The use of thermal sensing technology such as RTDs (resistance temperature detectors), integrated circuit sensors (IC), thermistors, IR thermometers, bimetallic, and thermocouples can also be used. Other sensors like photoelectric, photon, optics, indium-gallium-arsenide, and thermal detector could be used in place of IR for the detection of items placed on the surface.
Another embodiment provides a warmer drawer/multi-use drawer configured for outdoor locations having the ability to weather typical outdoor temperatures and environments. The use of electronics for warmer drawer/multi-use drawer can provide better sealing for use in these environments. With the use of remote locations for the electronic controls when the drawer 12 is used outdoors, the effects of the environment on the controls is minimized. Electronics are typically not subject to mechanical problems of “turning force” due to cold temperatures in certain locations. They are usually resistant to environmental conditions and problems to an extent unlike mechanical controls and switches, which can develop rusting or dust build-up for example. The electronic controls are also usually not subject to cleaning problems, as are mechanical controls. Electronic controls can be best suited for outdoor applications where extreme temperatures and weather conditions exist, because they typically have no (or minimal) mechanical moving parts to fail.
Another embodiment provides for the use of aromatic materials 90 such as favoring additives, e.g. wood clips, liquid smoke, etc.) or fragrances that can be added into a receptacle 92 within the chamber 16 to impart flavoring to food objects or desirable fragrances to non-food objects inside the chamber of the warmer drawer (see
According to another embodiment, the chamber 16 of the warmer drawer/multi-use drawer 12 may be illuminated when the drawer is opened or when a switch is turned on (see
According to another embodiment, the warmer drawer/multi-use drawer 12 may be configured for use through the electronic control system 40 to provide programmable set point(s), programmable set time(s) and programmable set operation(s) as well as multiples of set time(s), function(s), set points, operations or power on/off, by suitable interaction with the user interface. The ability to select multiple functions, operations and times gives the warmer drawer/multi-use drawer advantages over non-electronic controlled units. Timed on/off control can provide the ability to control the on/off time of the drawer. On/off time(s) can be infinitely set with the use of electronics. This programmability provides the advantage of being able to enter different functions or operations (e.g. more than one, etc.) into the electronic control system and have the warmer drawer/multi-use drawer control all desired functions, an advantage over mechanical or single function units. One can have one, two or more functions, operation(s), set point(s) with substantially limitless programming for control of these events. For example, one may start out with one temperature, at high temperature such as 200 degrees F. for one hour and then being able to reduce the temperature to 160 degrees F. for the remaining time. With a single function controlled warmer drawer the operator would typically have to manually reset the temperature. An electronically controlled warmer drawer/multi-use drawer (e.g. dual use drawer/triple use drawer) permits more user freedom.
A timer device, for example a clock, on the display device can also be provided, which can be changed to permit other programmable information to be displayed. Display illumination may also be selectable such that if the drawer is configured to expose the display, the display may serve as a night light or be adjusted for ease of viewing.
Another embodiment provides a warmer drawer/multi-use drawer 12 configured with a hinged door(s) (see
Referring to
According to another embodiment, the warmer drawer 12 may also be configured to cool (e.g. refrigerate) objects placed in the drawer. For example, a heat pump system may be substituted for the fan and heater (previously described). By further way of example, a magnetic refrigeration device, or may be a thermoelectric heating/cooling module (e.g. a Peltier-type device or module, etc.).
According to any exemplary embodiment, a warming apparatus such as a warmer drawer for use in stationary or mobile applications in any desirable environment is provided with an electronic controller that interfaces with a heating system (having one or more heating elements within the chamber or remote from the chamber, and that receive electrical power in a continuously variable and regulated manner to provide precise temperature control within a chamber), a ventilation system (including an air flow device such as a variable speed fan/motor, and a variably positionable louver/vent device driven by an actuator for air, heat and/or humidity control), a user interface (locally-controlled or remote-controlled) to permit a user to control the operation of the warmer drawer in a simple and convenient manner, and a display device arranged to provide information to a user in the form of alpha-numeric text messages (stationary or scrolling) and/or graphic images. The warmer drawer may be converted to a multi-use drawer by providing suitable elements within the chamber, (e.g. for cooling, or for other purposes such as baking, broiling, boiling, steaming, roasting, etc.). The warmer drawer may be installed in any convenient arrangement such as on a mobile pedestal, or supported by a cabinet, such as under a counter, or with a built-in oven as more fully described in a publication entitled Warming Drawer Installation Instructions, 803150/983-0152-000 REV C, 11/04, commercially available from Wolf Appliance Company LLC of Madison, Wis. The warmer drawer may also feature stainless steel construction, ball bearing drawer glides and accessories such as optional drawer fronts and racks for staking objects in the chamber, and may have an automatic shut-off mode, or a preset programming mode, and variable moisture selection operating features as more fully described in a publication entitled Warming Drawer Use & Care Information, 803149/983-0145-000 REV C, 1/04, commercially available from Wolf Appliance Company LLC of Madison, Wis.
The construction and arrangement of the elements of the warning apparatus as shown in the illustrated and other exemplary embodiments is illustrative only. Although only a few embodiments of the present inventions have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, circuit form, type and interaction, use of sensors, etc.) without materially departing from the novel teachings and advantages of the subject matter recited herein. For example, elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. Other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the preferred and other exemplary embodiments without departing from the scope of the present inventions.
The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. In the claims, any means-plus-function clause is intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Other substitutions, modifications, changes and omissions may be made in the design, operating configuration and arrangement of the preferred and other exemplary embodiments without departing from the spirit of the present inventions as expressed in the appended claims.
This Application claims the benefit of priority under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application No. 60/606,396 titled “Warmer Drawer” filed on Sep. 1, 2004, and U.S. Provisional Patent Application No. 60/622,185 titled “Non-Food Warmer Drawer” filed on Oct. 26, 2004 which are incorporated herein by reference in their entirety.
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