1. Field of the Invention
Embodiments of the present invention generally relate to a convection fan for ovens. More specifically, embodiments of the present invention relate to an after market device that can be incorporated in an ordinary oven to improve performance.
2. Description of the Related Art
As people become more aware of rising energy costs and environmental concerns, there is an opportunity to improve the efficiency of appliances and in particular household kitchen ovens. For new construction, renovations and replacements, consumers have the choice to upgrade the oven to a convection oven with a built-in convection fan. Consider that repairing an oven is common since replacement oven parts are widely available, inexpensive and easy to replace. Built-in ovens are often hard to match in size, color, style and require a licensed contractor to handle the electrical power connections. Thus, ovens last a long time.
This invention allows one to enhance an existing oven without the waste, cost, inconvenience, construction, time or hassle of matching appliances required when replacing an otherwise perfectly good oven.
It is well understood in thermodynamics that heat can be transferred using convection, conduction and/or radiation.
It is well understood that closed loop control systems and feedback control systems can be used to improve the individual characteristics of ovens, heaters, motors or fans. Previous to this invention, such closed loop control systems were restricted to include the oven device such as an integrated convection oven. Previous to this invention, the closed loop control system components necessary to operate in the harsh high temperature environment of an oven were expensive relative to the cost of a consumer oven or consumer oven accessory item.
It is well understood in cooking to display food temperature. It is well understood that temperature probes are used to monitor food temperature and signal an alarm or make a sound when a desired temperature is achieved. These devices are limited in ability and do not offer an air moving device and the related benefits.
Previous to this invention, one could purchase table top convention ovens and convection toaster ovens. These devices occupy additional counter space and lack the performance of a full size oven. The exteriors are generally hotter, the insulation is poorer and the efficiency is low when compared to a conventional oven. These devices include one or more heating elements that are more for reheating a small or single serving.
Previous to this invention, a variety of electric fans are available that operate at common room temperatures. These room temperature devices are unable to operate in the sustained high temperature environment found in or around a hot oven. Common fan parts made from plastic and rubber would melt. Paper parts would burn. Electrical insulation on wires and particularly motor windings would fail. Materials would expand and change shape causing moving parts to stick. Energy source devices such as batteries might even explode.
The present invention describes a system for an oven convection fan. This fan allows a user to upgrade the performance of their existing oven. The user obtains a simple and easy way to reduce power consumption, shorten cooking time, lower room temperature on a hot summer day, bake more uniformly, roast more consistently, and/or save money.
Variation of power source solutions, energy conversion solutions, transmissions solutions, air movement solutions, and/or control systems are combined to create similar yet different fans for use in ovens. Other solutions incorporate sensors to detect temperatures, count time, measure air flow rates, and/or measure power consumption to better control the system and/or report information to the user.
In some variations, the system is partitioned with some parts located outside of the oven while other parts are located within the oven. In this way, there is more flexibility in the ease of use and/or the high temperature design requirements for the system.
Power is equal to temperature multiplied by flux (heat flow rate). By raising the amount of air circulation, the oven can produce the same amount of power using a lower temperature at the heating element. Stated another way, given the same temperature at the heating element, the oven produces more power due to the higher flux. The ability to make adjustments in both temperature and flux increases the ability to properly control the cooking process.
Similarly the food (such as a turkey) within the oven cooks more evenly and quickly. Better circulation results in more consistent crusts when baking and crisp exteriors when roasting. Baking or roasting times can be shortened. Total power consumption can be reduced.
Many of the advantages of an integrated convection oven are obtained at a fraction of the cost. A separate convection fan device is also easily replaced and machine washable. Multiple fans can be used together.
A number of novel methods of locating the convection fan within the oven help to maximize useful space. The design of the fan is improved to produce more efficient air flow in low cost production methods. Some designs of the fan incorporate novel sources of power such as using the pre-existing oven light bulb socket and the pre-existing oven light switch.
Advantage of one or more disclosed embodiments may become apparent upon reading the following detailed description and upon reference to the drawings in which:
Described herein are exemplary systems and methods for an oven convection fan device. In the following description, numerous specific details are set forth to provide a thorough understanding of various embodiments. However, it will be understood by those skilled in the art that the various embodiments may be practiced without the specific details. In other instances, well known methods, procedures, components, and circuits have not been illustrated or described in detail so as not to obscure the particular embodiments.
The term “air moving device” includes but is not limited to turbines, propellers, impellers, blades, wings, blowers, pumps, compressors, rotating or non-rotational air moving devices, piezo electric vibrating devices, MEMS (Micro Electro Mechanical System), explosive devices, pressure difference generating devices, temperature difference generating devices, velocity difference generating devices, mass difference generating devices, arrays of air moving devices, and combinations of air moving devices.
The term “energy source device” includes but is not limited to electric, mechanical, human, fluidic, chemical, rotational, biological, nuclear, atomic, regenerative types of power, connectors to energy, energy plugs, energy sockets, and combinations of energy source devices. Electric power includes but is not limited to AC (alternating current), DC (direct current), switching, inductive, magnetic, hybrid, battery, thermal electric, and combinations of electric power types. Mechanical power includes but is not limited to spring, linear spring, weight, mass, and combinations of mechanical power types. Some sources of energy are stored locally such as from within a battery or spring while others are introduced externally such as from an electrical outlet, bulb socket or hand wound spring.
The term “power conversion device” includes but is not limited to motors, transformers, springs, linear springs, levers, pumps, gears, magnets, coils, wires, electronics, mechanisms, and combinations of power conversion devices.
The term “transmission device” includes but is not limited to shafts, gears, magnetic coupling, rods, arms, clutches, belts, cables, pulleys, bearings, rotational devices, linear motion devices, non-linear motion devices, and combinations of transmission devices.
The term “control device” includes but is not limited to on/off switches, variable switches, limit switches, electronic switches, mechanical switches, chemical switches, fluidic switches, micro switches, control systems, feedback control systems, closed loop control systems, open loop control systems, external switches, oven light bulb switches, touch sensors, smart grid controllers, power management controllers, safety switches, fuses, temperature controlled switches, thermostats, bi-metal materials, wireless control systems, wired control systems, remote control systems, motion sensing control systems, proximity control systems, software, computers, and combinations of control devices.
The term “mechanical device” includes but is not limited to hangers, stands, clips, trays, bars, screws, wires, silicon parts, metal parts, ceramic parts, stone parts, synthetic parts, high temperature parts and combinations of mechanical devices.
The term “lighting device” includes but is not limited to light bulbs, LED lights, chemical lights, gas fire, fire, light reflectors, lens, focusing systems, optical films, wave guides, fiber optics, photon emitting solutions and combinations of lighting devices.
The term “sensor” includes but is not limited to thermometers, thermistors, thermostats, thermocouples, bi-metal materials, timers, clocks, temperature measuring devices, flow measuring devices, pressure measuring devices, voltage meters, current meters, power measuring devices, ohm meters, capacitive sensors, resistive sensors, impedance sensors, electronic instruments, mechanical instruments, size measuring devices, scales, weight measuring instruments, moisture measuring instruments, odor detectors, flavor detectors, chemical measuring instruments, fire detectors, smoke detectors, carbon monoxide detectors, radiation detectors, infrared detectors, and combinations of sensors.
High temperature materials include but are not limited to metal, plastic, glass, ceramic, stone, silicone, silicon, plastics, fluorinated ethylene propylene (FEP), polychloro triflouroethylene (PCTFE), perflouroalkoxy (PFA), vespel polyiminde, polyetherether-ketone (PEEK), Meldin 7001, Torlon 4203, Rulon, polybenzimidazole (PBI), polyimides (PI), polyvinylidene fluoride (PVDF), polycarbonate, and combinations of high temperature materials. Electrical conductive high temperature materials are useful for but not limited to circuits, motors, switches, power supplies, batteries, wires, sockets, plugs, electromagnets, inductors, sensors, semiconductors, processors, and logic.
As cooking involves time 230, various temperatures, thermal flux rates and/or air flow rates 228, it is useful to know the measure of these values as they change. In control systems, these values are commonly called state variables. The temperature of various locations and elements are useful and include ambient temperature 220 of the room, oven temperature 222, heating element temperature(s) 224, and food temperature(s) 226.
The energy source device 110 is capable of withstanding the high temperatures found in or around an oven. A preferred embodiment of a high temperature energy source device 110 is a metal wind-up knob attached to a linear force spring. Another example of a high temperature energy source device 110 is to draw power from the oven light bulb socket.
The air moving device 140 is capable of withstanding the high temperatures found in or around an oven. A preferred embodiment of a high temperature air moving 140 device is a metal impeller or propeller. Another embodiment of a high temperature air moving device 140 is a silicone impeller or propeller.
The power conversion device 120 is capable of withstanding the high temperatures found in or around an oven. A preferred embodiment of a high temperature power conversion device 120 is a linear spring constructed from spring steel and related moving parts of metal. Another embodiment of a high temperature power conversion device 120 is an electric motor with high temperature insulation on the motor windings.
The transmission device 130 is capable of withstanding the high temperatures found in or around an oven. An embodiment of a high temperature transmission device 130 is a set of gears or shafts manufactured from metal.
The control device 170 is capable of withstanding the high temperatures found in or around an oven. An embodiment of a high temperature control device 170 is an on/off switch manufactured from metal.
The mechanical device 180 is capable of withstanding the high temperatures found in or around an oven. A preferred embodiment of a high temperature mechanical device 180 is a hanger made from metal. Another embodiment of a high temperature mechanical device 180 is a mating electrical connector that fits an existing oven light bulb socket.
An energy source device 110 is attached to an air moving device 140 using a power conversion device 120 and a transmission device 130. The rate of air movement is varied using a control device 170. An example of a basic control device 170 is a switch that turns the oven light and convection fan device 200 on and off. The oven light and convection fan device 200 is located within an oven using a mechanical device 180. An embodiment of the mechanical device 180 is to locate the oven convection fan and lights system 200 in a convenient position within the oven that occupies less space and/or improves air circulation.
The energy source device 110 is capable of withstanding the high temperatures found in or around an oven. An embodiment of a high temperature energy source device 110 is to draw power from the oven light bulb socket.
The air moving device 140 is capable of withstanding the high temperatures found in or around an oven. An embodiment of a high temperature air moving 140 device is a metal impeller or propeller. Another embodiment of a high temperature air moving device 140 is a silicone impeller or propeller.
The power conversion device 120 is capable of withstanding the high temperatures found in or around an oven. An embodiment of a high temperature power conversion device 120 is an electric motor with high temperature insulation on the motor windings.
The transmission device 130 is capable of withstanding the high temperatures found in or around an oven. An embodiment of a high temperature transmission device 130 is a set of gears or shafts manufactured from metal.
The control device 170 is capable of withstanding the high temperatures found in or around an oven. An embodiment of the control device 170 is to use the oven light on/off switch typically located outside of the oven chamber.
The mechanical device 180 is capable of withstanding the high temperatures found in or around an oven. An embodiment of a high temperature mechanical device 180 is a mating electrical connector that fits an existing oven light bulb socket
The lighting device 150 is capable of withstanding the high temperatures found in or around an oven. An embodiment of a high temperature light device 150 is an incandescent light bulb made mainly of glass and metal.
One embodiment of a control system is to use a bi-metal material (as commonly found in a thermostat) to automatically turn on the air moving device 140 above a given temperature and/or automatically turn off the air moving device 140 below the same or different temperature. In this way, the fan would automatically turn on and off.
Another use for the sensor information from one or more sensors 160 is to display status information to the user such as food temperature or cooking time remaining.
An energy source device 110 is attached to an air moving device 140 using a power conversion device 120 and a transmission device 130. The rate of air movement is varied using a control device 170. An example of a basic control device 170 is a switch that turns the oven convection fan and sensor(s) system 300 on and off. The oven convection fan and sensor(s) system 300 is located within an oven using a mechanical device 180. An embodiment of the mechanical device 180 is to locate the oven convection fan and sensor(s) system 300 in a convenient position within the oven that occupies less space and/or improves air circulation.
The energy source device 110 is capable of withstanding the high temperatures found in or around an oven. An embodiment of a high temperature energy source device 110 is a metal wind-up knob attached to a linear force spring. Another example of a high temperature energy source device 110 is to draw power from the oven light bulb socket.
The air moving device 140 is capable of withstanding the high temperatures found in or around an oven. An embodiment of a high temperature air moving 140 device is a metal impeller or propeller. Another embodiment of a high temperature air moving device 140 is a silicone impeller or propeller.
The power conversion device 120 is capable of withstanding the high temperatures found in or around an oven. An embodiment of a high temperature power conversion device 120 is a linear spring constructed from spring steel and related moving parts of metal. Another embodiment of a high temperature power conversion device 120 is an electric motor with high temperature insulation on the motor windings.
The transmission device 130 is capable of withstanding the high temperatures found in or around an oven. An embodiment of a high temperature transmission device 130 is a set of gears or shafts manufactured from metal.
The control device 170 is capable of withstanding the high temperatures found in or around an oven. An embodiment of a high temperature control device 170 is and on/off switch manufactured from metal.
The mechanical device 180 is capable of withstanding the high temperatures found in or around an oven. An embodiment of a high temperature mechanical device 180 is a hanger made from metal. Another embodiment of a high temperature mechanical device 180 is a mating electrical connector that fits an existing oven light bulb socket.
The sensor device(s) 160 is(are) capable of withstanding the high temperatures found in or around an oven. An embodiment of a high temperature resistant sensor device is a bi-metal strip that senses oven temperature. Another embodiment of a high temperature resistant sensor device that measures food temperature is a thermocouple.
The air moving propeller device 142 is turned on and off using a control device 170. An embodiment of the mechanical device 180 is a mechanical hanging device that suspends the wind-up propeller fan device 300 from an oven rack or shelf.
Air intake moves generally co-axially towards the propeller device 142. The air exhaust moves generally co-axially away from the propeller device 142.
The air moving impeller device 144 is turned on and off using a control device 170. A preferred embodiment of the mechanical device 180 is a mechanical hanging device that suspends the wind-up propeller fan device 300 from an oven rack or shelf.
Air intake moves generally co-axially towards the impeller device 144. The air exhaust moves generally radially away from the impeller device 144.
An embodiment of the air moving device is an impeller device 144 with air intake generally co-axial and air exhaust generally radial to the impeller device 144.
The energy source device is attached to the impeller device 144 through a power conversion device 120 and transmission device 130. An embodiment is to use a hand wound linear force spring. Another embodiment is to use a machine such as a power drill to assist in winding the linear force spring.
The power conversion device 120 converts the electrical energy to rotational energy which is transmitted to the air moving device 140 using a transmission device 130. An embodiment of the power conversion device 120 is an electric motor with high temperature windings 420, high temperature rotor 432, and high temperature motor bearing 422 able to operate at the temperatures commonly found within an oven.
The transmission device 130 connects the motor rotor 432 to the air moving device 140. The air moving device 140 draws air into the air intake 436 and pushes air out the exhaust 434.
We teach that the control device is provided by the oven light bulb switch located externally to the oven chamber.
The mechanical device 180 is fitted to the oven light bulb socket. An embodiment is to use a screw thread 430 that mates with the existing oven light bulb socket. The shape of the oven light and convection fan device 400 is designed to mate the existing oven light bulb opening allowing the lighting device 150 to perform in a similar manner as the original oven light bulb.
The transmission device is partitioned such that the outside magnets 530 of the transmission device are located outside of the oven 502 and the inside magnets 532 of the transmission device are located inside of the oven 504. The outside magnets 530 of the transmission device creates a magnetic force which is transmitted through the oven door glass 506 driving the inside magnets 532.
The air moving device 140 is located inside the oven 504. The air moving device 140 is propelled by the energy source device 110 through the power conversion device 120 and transmission devices outside magnets 530 and inside magnets 532.
The mechanical device 180 is located on both the inside 502 and outside 504 of the oven door glass 506. An embodiment of the mechanical device 180 is to use magnets.
The air moving device 140 is located inside the oven 504. The air moving device 140 is propelled by the inductive energy source device 560 through the inductive energy receiver 562, and power conversion device 120.
The mechanical device 180 is located on both the inside 502 and outside 504 of the oven door glass 506. An embodiment of the mechanical device 180 is to use magnets.
A flexible cable 630 is routed around the oven door 508 and used as a transmission device to attach the power conversion device 120 to the air moving device 140. An embodiment of the flexible cable 630 is a spiral metal drive shaft with a metal sleeve that is thin enough to fit around the oven door 508 insulation or gaps in the insulation.
The air moving device 140 is located inside the oven 504. The mechanical device 180 is located on both the inside and outside of the oven door 508. An embodiment of the mechanical device 180 is to use magnets.
A flexible belt device 660 is routed around the oven door 508 and used as a transmission device to attach the power conversion device 120 to the air moving device 140. An embodiment of the flexible belt 660 is a thin metal strap within a metal sleeve that is thin enough to fit around the oven door 508 insulation or gaps in the insulation.
The air moving device 140 is located inside the oven 504. The mechanical device 180 is located on both the inside 502 and outside 504 of the oven door 508. An embodiment of the mechanical device 180 is to use magnets.
The control function 760 accepts the state variables 750 to produce a control vector 730. The control vector 730 is combined with the input vector 710 using a sum device 720. In this way, the input control vector 730 values are modified before being used by the oven control device to more precisely achieve the desired cooking result.
The display 780 allows the user to observe the values for one or more state variables 750. One embodiment is to show an indication of the food temperature. Another embodiment is to show an indication of the amount of time remaining before the desired cooking is completed.