WO1999030565A1 - Lightwave oven having automatic food conveyor - Google Patents

Abstract

A lightwave conveyor oven (10) and method of cooking using a lightwave conveyor oven (10). The oven has food entry and exit ports, a food conveyor (24a-24c, 26, 28, 29a and 29b) extending through the oven chamber, and at least one lightwave cooking lamp disposed in the chamber.

Description

Lightwave Oven Having Automatic Food Conveyor

This application claims the benefit of U.S. Provisional Appln. No. 60/069,813, filed December 17, 1997.

Field of the Invention

This invention relates to the field of lightwave or radiant source ovens. More particularly, this invention relates to lightwave ovens having conveyor mechanisms which carry food items beneath or between arrays of radiant energy sources.

Background of the Invention

Ovens for cooking and baking food have been known and used for thousands of years. Basically, oven types can be categorized in four cooking forms; conduction cooking, convection cooking, infra-red radiation cooking and microwave radiation cooking.

There are subtle differences between cooking and baking. Cooking just requires the heating of the food. Baking of a product from a dough, such as bread, cake, crust, or pastry, requires not only heating of the product throughout but also chemical reactions coupled with driving the water from the dough in a predetermined fashion to achieve the correct consistency of the final product and finally browning the outside. Following a recipe when baking is very important. An attempt to decrease the baking time in a conventional oven by increasing the temperature results in a damaged or destroyed product.

In general, there are problems when one wants to cook or bake foodstuffs with high-quality results in the shortest times. Conduction and convection provide the necessary quality, but both are inherently slow energy transfer methods. Long-wave infra-red radiation can provide faster heating rates, but it only heats the surface area of most foodstuffs, leaving the internal heat energy to be transferred by much slower conduction. Microwave radiation heats the foodstuff very quickly in depth, but during baking the loss of water near the surface stops the heating process before any satisfactory browning occurs. Consequently, microwave ovens cannot produce quality baked foodstuffs, such as bread.

Radiant cooking methods can be classified by the manner in which the radiation interacts with the foodstuff molecules. For example, starting with the longest wavelengths for cooking, the microwave region, most of the heating occurs because the radiant energy couples into the bipolar water molecules causing them to rotate. Viscous coupling between water molecules converts this rotational energy into thermal energy, thereby heating the food. Decreasing the wavelength to the long-wave infra-red regime, the molecules and their component atoms resonantly absorb the energy in well-defined excitation bands. This is mainly a vibrational energy absorption process. In the near-visible region of the spectrum, the main part of the absorption is due to higher frequency coupling to the vibrational modes. In the visible region, the principal absorption mechanism is excitation of the electrons that couple the atoms to form the molecules. These interactions are easily discerned in the visible band of the spectra, where they are identified as "color" absorptions. Finally, in the ultraviolet, the wavelength is short enough, and the energy of the radiation is sufficient to actually remove the electrons from their component atoms, thereby creating ionized states and breaking chemical bonds. This short wavelength, while it finds uses in sterilization techniques, probably has little use in foodstuff heating, because it promotes adverse chemical reactions and destroys food molecules. Lightwave ovens utilizing sources of visible, near-visible and infra-red radiant energy are disclosed and described in U.S. Patent No. 5,036,179 and U.S. Patent No. 5,517,005 which are incorporated herein by reference. These ovens provide high-speed, high-quality cooking and baking of food items by impinging high-intensity visible, near-visible, and infrared radiations onto a food item. Lightwave ovens cook the food items within the short periods of time normally found in microwave cooking while maintaining the browning of infrared cooking and the quality of conduction-convection cooking.

This cooking speed is attributable to the range of wavelengths and power levels that are used.

Typically, wavelengths in the visible range (.39 to .77 μm, or reduced visible range 0.4 to 0.7 μm) and the near-visible range (.77 to 1.4 μm) have fairly deep penetration in most foodstuffs. This range of deep penetration is mainly governed by the absorption properties of water. The characteristic penetration distance for water varies from about 50 meters in the visible to less than about 1 mm at 1.4 microns. Several other factors modify this basic absorption penetration. In the visible region electronic absorption of the food molecules reduces the penetration distance substantially, while scattering in the food product can be a strong factor throughout the region of deep penetration. Measurements show that the typical average penetration distances for light in the visible and near-visible region of the spectrum varies from 2-4 mm for meats to as deep as 10 mm in some baked goods and liquids like non-fat milk.

The region of deep penetration allows the radiant power density that impinges on the food to be increased, because the energy is deposited in a fairly thick region near the surface of the food, and the energy is essentially deposited in a large volume, so that the temperature of the food at the surface does not increase rapidly. Consequently the radiation in the visible and near-visible regions does not contribute greatly to the exterior surface browning.

In the region above 1.4 μm (infrared region), the penetration distance decreases substantially to fractions of a millimeter, and for certain absorption peaks down to 0.001 mm. The power in this region is absorbed in such a small depth that the temperature rises rapidly, driving the water out and forming a crust. With no water to evaporate and cool the surface the temperature can climb quickly to 300° F. This is the approximate temperature where the set of browning reactions (Maillard reactions) are initiated. As the temperature is rapidly pushed even higher to above 400° F the point is reached where the surface starts to burn.

It is the balance between the deep penetration wavelengths (.39 to 1.4 μm) and the shallow penetration wavelengths (1.4 μm and greater) that allows the power density at the surface of the food to be increased in the lightwave oven, to cook the food rapidly with the shorter wavelengths and to brown the food with the longer infrared so that a high-quality product is produced. Conventional ovens do not have the shorter wavelength components of radiant energy. The resulting shallower penetration means that increasing the radiant power in such an oven only heats the food surface faster, prematurely browning the food before its interior gets hot.

It should be noted that the penetration depth is not uniform across the deeply penetrating region of the spectrum. Even though water shows a very deep penetration for visible radiation, i.e., many meters, the electronic absorptions of the food macromolecules generally increase in the visible region. The added effect of scattering near the blue end (.39 μm) of the visible region reduces the penetration even further. However, there is little real loss in the overall average penetration because very little energy resides in the blue end of the blackbody spectrum. Conventional ovens operate with radiant power densities as high as about 0.3 W/cm² (i.e. at 400 °F). The cooking speeds of conventional ovens cannot be appreciably increased simply by increasing the cooking temperature, because increased cooking temperatures drive water off the food surface and cause browning and searing of the food surface before the food's interior has been brought up to the proper temperature. In contrast, lightwave ovens have been operated from approximately 0.8 to 5 W/cm² of visible, near-visible and infrared radiation, which results in greatly enhanced cooking speeds.

The lightwave oven energy penetrates deeper into the food than the radiant energy of a conventional oven, thus cooking the food interior faster. Therefore, higher power densities can be used in a lightwave oven to cook food faster with excellent quality. For example, at about

0.7 to 1.3 W/cm², the following cooking speeds have been obtained using a lightwave oven:

Food Cook Time pizza 4 minutes steaks 4 minutes biscuits 7 minutes cookies 11 minutes vegetables (asparagus) 4 minutes

For high-quality cooking and baking, the applicant has found that a good balance ratio between the deeply penetrating and the surface heating portions of the impinging radiant energy is about 50:50, i.e., Power(.39 to 1.4//m)/Power(1.4μm and greater) » 1. Ratios higher than this value can be used, and are useful in cooking especially thick food items, but radiation sources with these high ratios are difficult and expensive to obtain. Fast cooking can be accomplished with a ratio substantially below 1 , and it has been shown that enhanced cooking and baking can be achieved with ratios down to 0.4 (40:60, or 40% in the range of .39 to 1.4) for most foods, and lower for thin foods, e.g., pizza and foods with a large portion of water, e.g., meats. Generally the surface power densities must be decreased with decreasing power ratio so that the slower speed of heat conduction can heat the interior of the food before the outside burns. It should be remembered that it is generally the burning of the outside surface that sets the bounds for maximum power density that can be used for cooking. If the power ratio is reduced below about 0.25 (25:75), the power densities that can be used are comparable with conventional cooking and no speed advantage results.

If blackbody sources are used to supply the radiant power, the power ratio can be translated into effective color temperatures, peak intensities, and visible component percentages. For example, to obtain a power ratio of 1 , it can be calculated that the corresponding blackbody would have a temperature of 3000°K, with a peak intensity at .966 μm and with 12% of the radiation in the full visible range of .39 to .77 μm (or 10% in the reduced visible range of 0.4 to 0.7 μm). Tungsten halogen quartz bulbs have spectral characteristics that follow the blackbody radiation curves fairly closely. Commercially available tungsten halogen bulbs have successfully been used with color temperatures as high as 3400 °K. Unfortunately, the lifetime of such sources falls dramatically at high color temperatures (at temperatures above 3200 °K it is generally less that 100 hours). It has been determined that a good compromise in bulb lifetime and cooking speed can be obtained for tungsten halogen bulbs operated at about 2900-3000 °K. As the color temperature of the bulb is reduced and more shallow-penetrating infrared is produced, the cooking and baking speeds are diminished for quality product. For most foods there is a discernible speed advantage down to at least 2500° K (peak at about 1.2 /m; full range visible component of about 5.5%) and for some foods there is an advantage at even lower color temperatures. In the region of 2100°K the speed advantage vanishes for virtually all foods that have been tried. For rectangular-shaped commercial lightwave ovens using polished, high-purity aluminum reflective walls, it has been determined that about 4 KW of lamp power is necessary for a lightwave oven to have a reasonable cooking speed advantage over a conventional oven. Four kilowatts of lamp power can operate four commercially available tungsten halogen lamps, at a color temperature of about 3000°K, to produce a power density of about 0.6-1.0 W/cm² inside the oven cavity. This power density has been considered near the minimum value necessary for the lightwave oven to clearly outperform a conventional oven. It has been discovered that the uniform time-average power density can be optimized in lightwave ovens by improving the reflectivity of the oven wall materials and by optimizing the reflective characteristics of the oven geometry. Uniform cooking of foodstuffs is achieved by using novel reflectors adjacent to the lamps.

Lightwave ovens can use one or more lamps, such as commercially available tungsten halogen lamps, or an array of several lamps either operated in unison or selectively operated in varying combinations as necessary for the particular food item sought to be cooked. These radiation sources are ordinarily positioned on opposite sides of the food item. The walls of the surrounding food chamber are preferably made from highly reflective surfaces. The visible and infrared waves from the radiation sources impinge directly on the food item and are also reflected off the reflective surfaces and onto the food item from many angles. This reflecting action improves oven efficiency uniformity of cooking.

Conveyor driven grilling and broiling devices are currently available for commercial applications. A device of this type typically includes a chamber having open ends and containing infrared cooking elements, and a horizontal conveyor belt which carries food into one open end, through the cooking chamber, and out the other end. Such devices may not be well suited for lightwave cooking applications for a number of reasons.

For example, because the ends of the oven are open, radiant energy emitted by the lamps could exit the oven through the open ends, decreasing the amount of direct and reflected radiant energy striking the food and thus compromising oven efficiency. Moreover, food traveling on the horizontally-extending conveyor can produce drippings which can land and dry on the lamps. While this may not present a significant problem for conventional cooking techniques which rely on heat conduction for cooking, it may have a significant negative impact on lightwave cooking efficiency. This is because in lightwave cooking it is the action of the radiant energy on and beneath the food surface, rather than heat conduction alone, which is the primary mechanism for cooking the food. Food drippings on the lamps (or on shields positioned between the food and the lamps) would block transmission of radiant energy from the lamps and thus decrease cooking efficiency.

It is therefore desirable to provide a conveyor-style cooking apparatus which affords the convenience of conventional conveyor cooking devices but which accommodates lightwave cooking techniques.

Summary Of The Invention

The present invention is a lightwave conveyor oven and method of cooking using a lightwave conveyor oven. The oven includes an oven chamber having a food entry port and a food exit port, a moveable food conveyor extending through the oven chamber, and at least one lightwave cooking lamp disposed within the chamber. During use, the lightwave cooking lamp is illuminated, causing it to emit lightwave cooking energy. An item of food is placed on the moveable conveyor, and the conveyor is caused to move the food through the oven chamber causing the food to be exposed to the lightwave cooking energy.

Brief Description Of The Drawings

Fig. 1 is a partially cut away perspective view of a first embodiment of a lightwave conveyor-style cooking apparatus according to the^' present invention.

Fig. 2 is a front elevation view of the support panel of the lightwave conveyor oven of Fig. 1.

Fig. 3 is a front elevation view of a lamp reflector of the lightwave conveyor oven of Fig. 1.

Fig. 4 is a cross-sectional end view of the lamp reflector of Fig. 3.

Fig. 5 is a side plan view of the lamp reflector of Fig. 4.

Fig. 6 is a perspective view of a second embodiment of a lightwave conveyor-style cooking apparatus.

Fig. 7 is a side elevation view of a third embodiment of a lightwave conveyor-style cooking apparatus.

Detailed Description

Referring to Fig. 1 , a first embodiment of a lightwave conveyor oven 10 is particularly suitable for roasting, cooking, broiling or baking items such as meats and bread products which can be passed through a cooking chamber on a vertical conveyor. One or more cooking lamps are positioned within the cooking chamber. The vertical orientation of this embodiment is desirable in that it prevents drippings and crumbs from falling onto the lamps or lamp shields where they might reduce transmission of radiant energy and thus decrease cooking efficiency. However, as can be readily appreciated, a horizontal or other non-vertical lightwave cooking conveyor may alternatively be used and produce highly beneficial cooking results. The first embodiment includes a housing 12 having a front wall 14 and a rear wall 16. Pairs of spaced support panels 18 are mounted inside the housing 12 near both the front and rear walls 14, 16 (only the front support panels can be seen in Fig. 1).

As shown in Fig. 2, the support panels are formed of substantially rectangular sheets of reflective material, such as Alanod aluminum or other highly polished metal. Each support panel is provided with three holes 20, each located near a corner of the rectangular sheet. An elongate slot 22 is formed in the support panel 18 next to a pair of the holes 20.

Referring again to Fig. 1 , six spring loaded corner rollers 24a, 24b, 24c are rotatably mounted within the holes 20 and extend between the front and rear support panels 18. Two top rollers 26 are rotatably mounted to extend between the interior surfaces of the front and back walls 14, 16. As can be seen in the drawings, the top rollers 26 are vertically aligned with the outermost corner rollers 24c and are located higher within the chamber than are the uppermost corner rollers 24a.

At each side of the chamber, a belt 28 extends around a top roller 26 and three corner rollers 24a,b and c to form a loop. There are therefore two loops within the chamber: a first loop 29a which in Fig. 1 is located at the left side of the chamber, and a second loop 29b which is at the right side of Fig. 1. Because the top rollers 26 are located at higher points within the oven than are the uppermost corner rollers 24a, each loop has a top side 31a which angles downwardly towards the opposing belt. Each belt further includes substantially vertical side sections 31b, 31c and a substantially horizontal bottom section 31 d. A motor is engaged to at least some of the belts to cause movement of the belts when activated.

Each belt is preferably a stainless steel wire link belt utilizing 1/2" pitch, 0.72 inch diameter wire. The interior side sections 31b of the belts are spaced from one another by a distance selected so that food items having common thickness (i.e. a common range of thicknesses for chicken, steaks and other types of food likely to be cooked using an apparatus of this type), will become engaged between the interior side sections 31b, as will be described in detail below. The spacing may be manually or automatically adjustable to allow the conveyor to be used for a variety of foods having a variety of food thicknesses.

Highly reflective (e.g. made from highly polished metal such as Alanod aluminum) reflectors 30 are mounted between the vertical side sections 31b, 31c of each of the belt loops 29a, 29b. Referring to Figs. 3-5, each reflector 30 includes a rectangular plate 32, a pair of walls 34 extending angularly from the plate, and pair of beveled sections 36 extending angularly from the walls 34. It should be appreciated that other reflector configurations may be envisioned to optimize the amount of radiant energy from the lamps that is reflected onto the food. Slots 38a, 38b are formed in the walls 34 and are proportioned for receiving elongate lamps 39, with each lamp 39 supported between one of the slots 38a and a corresponding slot 38b. In the embodiment shown in the drawings, the reflectors are configured such that an array of seven such lamps are mounted in each reflector. The lamps are secured in these positions and electrically connected to a power source using conventional means.

Lightwave cooking lamps producing visible, near-visible and infrared radiation as described in the Background section, such as quartz-halogen tungsten lamps, quartz-arc lamps or equivalent lamps are preferably used in the embodiments described herein. The lamps are preferably operated at a color temperature of at least 2100°K, preferably between 2500 and 3000° K, and most preferably above 2800°K, to take full advantage of the amounts of visible and near- visible radiant energy emitted at these color temperatures. It has been found that cooking with at least approximately 40-50% of the radiant energy in the visible and near-visible ranges of the electromagnetic spectrum provides substantial speed advantages over conventional cooking techniques using primarily infrared energy. If blackbody sources are used, 40% of the radiant energy in the range of .39 - 1.4 microns correlates to a color temperature of approximately 2560°K.

Lamp shields 46 are disposed within the elongate slots 22 in the support plates 18, such that each lamp shield 46 extends between a front and a rear lamp plate 18 and such that each array of seven lamps is disposed between a reflector plate 32 and a lamp shield 46. The shields can be formed from materials, such as high quality heat- resistant glasses and pyroceramic materials, that are transparent to visible, non-visible and infrared radiations. The shields are plates made of a glass or a glass-ceramic material that has a very small thermal expansion coefficient. For the preferred embodiment glass- ceramic material available under the trademarks Pyroceram, Neoceram and Robax, and the glass material available under the name Pyrex, may be used. These lamp shields isolate the lamps and reflecting surfaces so that drips, food splatters and food spills do not affect operation of the oven, and they are easily cleaned since each shield consists of a single, plate of glass or glass-ceramic material.

Mounted at the bottom of the chamber is a base wall 40 (Fig. 5) which includes a rectangular cutout 42. A top wall 44 having a similar cutout (not shown) forms the top of the chamber housing).

During use, a motor is activated to cause rotation of the rollers. The roller spindles engage the loops 29a, 29b, causing them to move continuously in the direction of the arrows shown in Fig. 1 (i.e., such that the angled top portions 31a and the inner side portions 31b move downwardly). Items of food are introduced into the chamber via the cutout in the top wall 44 of the housing, and fall onto top portions 31a or inner side portions 31b of the loops 29a, 29b. Movement of the loops 29a, 29b carries the food between the loops, such that the food becomes pinched between inner side portions 31b.

A sensor detects the presence of food items entering the chamber, and, in response, causes a signal to be initiated which causes the lamps to be illuminated. The food is carried through the chamber by the belts where it is exposed to the cooking effects of the lamps. The speed with which the conveyor carries the food through the chamber depends on the amount of power which will be delivered by the lamps and the amount of time needed to cook the food at the given power.

When the food reaches the lowermost end of inner side portions 31 b, it is released from the loops 29a, 29b and drops out of the chamber via the cutout 42. Beneath the base wall 40 is a catch container 46, shown in Fig. 1 , in which the cooked food is collected. A second sensor located at the bottom of the chamber senses the food as it exits the chamber and, if no subsequently placed food items have entered the chamber, it initiates a signal which causes the lamps to be turned off.

A second embodiment of a lightwave conveyor oven is shown in Fig. 6. The second embodiment is preferably a conveyor oven having a conveyor 100 which carries food through a lightwave cooking section 102 and a conventional cooking section 104. The conventional cooking section 104 may be of the type in which infrared cooking elements and/or fixtures for cooking by directing heated air onto the foodstuffs are located within a housing through which the conveyor 100 passes. In a preferred embodiment, the conventional and lightwave cooking sections are adjacent to one another, although other configurations are possible. For example, the lightwave and conventional cooking fixtures may be housed together in a single housing. As another alternative, the lightwave cooking conveyor may be provided without a conventional cooking component and be used on its own for cooking and/or baking.

The lightwave cooking section 102 includes a reflectorized box 106 having lightwave cooking elements 108 of the types described above installed inside. The lightwave cooking elements 108 may be positioned in a number of configurations within the box, such as above and/or below the conveyor. It may be desired to fit the box 106 to have baffles which minimize the amount of radiant energy which can escape from the box 106 and which thereby minimize losses of efficiency. The front edge of the reflectorized box 106 (i.e. the edge below which the food enters the box 106) may extend well beyond the regions in which the elements 108 are mounted to minimize loss of radiant energy out the opening of the oven. The edge may also be blackened to prevent radiant energy from reflecting off the edge of the reflector box and out of the oven.

Lightwave conveyor ovens according to the present invention are preferably configured so that the lamps may be independently controlled, and so that their intensities may be modulated so that particular types of food items get the proper amount of cooking energy. This is desirable because different foods have different absorption characteristics and thus cook differently when exposed to lightwave cooking energy. Thus, for example, the lamps may operate at a certain percentage of full intensity to cook a meat product, and then adjusted to another percentage of full intensity to cook a pizza or baked product.

Referring to Fig. 6, a plurality of sensors 110 may be arranged within the box 106, such as beneath the conveyor. The sensors detect the presence and location of food entering the oven and initiate illumination of the cooking elements 108 to which the food will be exposed as it travels along the conveyor. As can be seen in Fig. 6, one group of lamps is illuminated due to detection of a pizza by the sensors. Another group of lamps has remained in an "off¹ condition because no food has been detected by the sensors corresponding to that section of the lamp array.

During a cooking cycle, the food may first be subjected in the lightwave component 102 to deeply penetrating radiation in the visible and near-visible range of the electromagnetic spectrum in order to quickly heat the interior regions of the food. The food is then carried into the conventional component where the food is browned and finished using conventional hot air and infra-red heating.

The conveyor oven according to the second embodiment has a number of advantages over conventional conveyor ovens. First, it is capable of quickly cooking foods to a high level of quality. Second, it allows for instantaneous and independent heating control of serially placed food items. Thus, the oven could cook and bake a variety of foods that could not be sequentially cooked and/or baked using a constant power conveyor in which only the conveyor belt speed could be adjusted. Thus, for example, a pizza could be cooked in the oven and be immediately followed by a bread product or another type of food without adjusting belt speed as must be done using conventional conveyor ovens. Instead, lamp intensity (or color temperature) may be adjusted upwardly or downwardly between food items to appropriately cook each type of food placed into the oven. A third advantage is that, because the conventional portion 104 of the oven is to be used only for finishing the cooking cycle, the conventional portion and the conveyor may be made shorter (in terms of the length of the conveyor travel path) than in conventional conveyors and so the oven may be provided to have a much smaller footprint than that currently found on conveyor ovens.

Conventional pizza conveyor ovens which direct heated air at high velocities onto the food during cooking can also suffer from a problem in which pizza toppings are propelled off of the pizzas by the streams of heated air. Another advantage of the oven is that it avoids this problem because the pizza cheese is melted during the lightwave cooking step, and so the toppings adhere to the melted cheese by the time the pizza reaches the heated air stream.

Yet another advantage of the second embodiment is that the lightwave cooking component may be adapted to mount onto already existing conveyor ovens. Fig. 7 shows a third embodiment of a conveyor oven according to the present which, like the second embodiment, is a combination lightwave/conveyor oven. The third embodiment is particularly suitable for retrofitting existing conventional convection ovens having conveyor belts. It includes a reflector having lamps of the type used for lightwave cooking mounted therein. The lamps are preferably oriented such that the long axis of each lamp is not parallel to the plane of the conveyor belt as shown, although they may be positioned such that they extend parallel to the food conveyor. A series of lamps is mounted within the reflector to achieve the appropriate power density while minimizing space over the conveyor and thus minimizing the overall footprint needed for the oven.

A source of a portion of the heated air used to cook the food in the convection portion of the oven may be in the air that is typically used to cool lightwave cooking lamps to maintain lamp efficiency. In typical lightwave ovens, the air that is used to cool the lamps is vented from the ovens. In a conveyor oven according to the second or third embodiments, this air, which is ultimately heated by the lamps, can be used to form a "hot air curtain" at the entrance to the oven, or to preheat the convection portion of the oven, or (if sufficiently heated) to perform direct cooking of the food.

While the subject invention has been described with reference to three embodiments, various changes and modifications could be made therein, by one skilled in the art, without varying from the scope and spirit of the subject invention as defined by the appended claims.

Claims

What is claimed is:

1. A lightwave conveyor oven comprising: an oven chamber having a food entry port and a food exit port; a moveable food conveyor extending through the oven chamber; and at least one lightwave cooking lamp disposed within the chamber.

2. The lightwave conveyor oven of claim 1 wherein the lightwave cooking lamp is operable to emit radiant energy having a visible and near-visible component of at least approximately 40%.

3. The lightwave conveyor oven of claim 1 wherein the lightwave cooking lamp is operable at a color temperature of at least approximately 2500┬░K.

4. The lightwave conveyor oven of claim 1 wherein the lightwave cooking lamp is operable at a color temperature of at least approximately 2800┬░K.

5. The lightwave conveyor oven of claim 1 , wherein the moveable conveyor is fully disposed within the oven chamber.

6. The lightwave conveyor oven of claim 1 wherein the moveable conveyor is vertically oriented.

7. The lightwave conveyor oven of claim 1 , further comprising a conventional cooking element positioned to direct heat onto the moveable conveyor.

8. The lightwave conveyor oven of claim 7 wherein the conventional cooking element is an infrared cooking element.

9. The lightwave conveyor oven of claim 7 wherein the conventional cooking element is a source of heated air directed onto the conveyor.

10. The lightwave conveyor oven of claim 7 wherein the conventional cooking element is mounted within the oven chamber.

11. The lightwave conveyor oven of claim 7, further comprising a second oven chamber adjacent to the oven chamber, and wherein the conventional cooking element is mounted within the second oven chamber.

12. The lightwave conveyor oven of claim 1 , further including a baffle at the entry port to minimize escape of radiant energy from the chamber.

13. The lightwave conveyor oven of claim 1 , further including a baffle at the exit port to minimize escape of radiant energy from the chamber.

14. A method of cooking using a lightwave oven, comprising:

(a) providing a lightwave oven having an oven chamber, a moveable conveyor extending through the oven chamber, and a lightwave cooking lamp disposed within the oven chamber;

(b) illuminating the lightwave cooking lamp, causing it to emit lightwave cooking energy;

(c) placing an item of food on the moveable conveyor; and (d) causing the conveyor to move the food through the oven chamber causing the food to be exposed to the lightwave cooking energy.

15. The method of claim 14 wherein the lightwave cooking energy emitted in step (b) includes a visible and near-visible component of at least approximately 40% of the radiant energy emitted by the lamp.

16. The method of claim 14 wherein in step (b) the lamp is illuminated at a color temperature of at least approximately 2500┬░K.

17. The method of claim 14 wherein in step (b) the lamp is illuminated at a color temperature of at least approximately 2800┬░K.

18. The method of claim 14 wherein the method includes the step of sensing for the presence of on the conveyor prior to step (b), and then initiating step (b) upon detection of food by the sensor.

19. The method of claim 15 wherein the method further includes sensing to detect the food item exiting the oven and then turning off the lightwave cooking lamp after the food item has been detected to have exited the oven.

20. The method of claim 14 wherein in step (b) the lamp is illuminated to a predetermined percentage of full lamp power, and wherein the method further comprises the steps: placing a second food item on the moveable conveyor; and illuminating the lightwave cooking lamp to a second predetermined percentage of full lamp power.

21. The method of claim 14 wherein the method further comprises a conventional cooking element positioned to direct heat onto the moveable conveyor, wherein the method further includes causing the conventional cooking element to emit heat, and wherein step (d) further includes causing the conveyor to move the food through the oven chamber causing the food to be exposed to the heat emitted from the conventional cooking element.