Title:
CONVEYOR OVEN WITH MULTIPLE HEATING ZONES
Kind Code:
A1


Abstract:
Multiple top-mounted heaters and at least one bottom heater define multiple heating/cooking zones in a conveyor oven. The top-mounted heaters output different energy levels and thereby define heating/cooking zones whereat foods are cooked differently. By using multiple bottom-mounted heaters, thermal separation of the heating zones can be further enhanced. Liquids, such as air, water, oil or a combination of all three can be sprayed onto foods during the cooking process to control cooking.



Inventors:
Burtea, Sanda (Lindenhurst, IL, US)
Burtea, Constantin (Lindenhurst, IL, US)
Burtea, Sanda (Lindenhurst, IL, US)
Agnello, Frank Anthony (South Elgin, IL, US)
Van Erden, Don (Wildwood, IL, US)
Application Number:
11/830411
Publication Date:
02/05/2009
Filing Date:
07/30/2007
Primary Class:
Other Classes:
126/21A
International Classes:
F24C1/02; F24C15/32
View Patent Images:
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Primary Examiner:
CAMPBELL, THOR S
Attorney, Agent or Firm:
Docket Clerk (Downers Grove, IL, US)
Claims:
What is claimed is:

1. An oven comprising: a cavity having a top, a bottom, a first opening and a second opening; a single, loop conveyor within the cavity, the loop conveyor (conveyor) extending between and capable of moving items on the conveyor in a first direction that is from the first opening to the second opening, the conveyor having a first side and a second side, the first and second sides defined by a geometric line extending between, and substantially orthogonal to, the first and second openings; a first top-mounted heater which directs infrared heat downwardly, infrared heat from the first top-mounted heater being directed toward the first side of the conveyor; a second top-mounted heater which directs infrared heat downwardly, infrared heat from the second top-mounted heater being directed toward the second side of the conveyor; and a first bottom mounted heater which directs infrared heat upwardly toward the first and second sides of the conveyor.

2. The oven of claim 1, wherein the conveyor is a variable speed conveyor.

3. The oven of claim 1 further comprised of a baffle between the first and second top-mounted heaters, said baffle directing and reflecting heat from the first top-mounted heater toward the first side of the conveyor and directing and reflecting heat from the second top-mounted heater toward the second side of the conveyor.

4. The oven of claim 1, wherein the first and second top-mounted heaters are capable of having infrared heat output levels that are different from each other and wherein the infrared heat output levels of the first and second top-mounted heaters are separately and individually adjustable.

5. The oven of claim 4 wherein at least one of the first and second top-mounted heaters are electrically-powered quartz heaters.

6. The oven of claim 5 further comprised of an electrical resistor electrically connected between the first and second top-mounted heaters to determine the heat output from the first and second top-mounted heaters.

7. The oven of claim 5 further comprised of a first variable power source coupled to and providing power to the first top mounted heater and a second variable power source coupled to and providing power to the second top mounted heater.

8. The oven of claim 4 wherein at least one of the first and second top-mounted heaters are gas-fired infrared heaters.

9. The oven of claim 1 wherein the first bottom-mounted burner is an electrically-powered quartz heater.

10. The oven of claim 1 wherein the first bottom-mounted burner is a gas-fired burner.

11. The oven of claim 1 wherein the first bottom-mounted heater directs infrared heat upwardly toward the first side of the conveyor and wherein the oven includes a second, bottom-mounted heater directing infrared heat upwardly toward the second side of the conveyor.

12. The oven of claim 11, wherein the heat output of the first bottom-mounted heater and the heat output of the second bottom-mounted heater are separately and individually adjustable.

13. The oven of claim 12 further comprised of an electrical resistor electrically connected between the first and second bottom-mounted heaters to determine the heat output from the first and second bottom-mounted heaters.

14. The oven of claim 12 further comprised of a first variable power source coupled to and providing power to the first bottom-mounted heater and a second variable power source coupled to and providing power to the second bottom-mounted heater.

15. The oven of claim 1, wherein substantially more than fifty percent (50%) of the infrared heat energy from the first top-mounted heater is directed to the first side of the conveyor and substantially more than fifty percent (50%) of the infrared heat energy from the second top-mounted heater is directed to the second side of the conveyor.

16. The oven of claim 1 wherein the single variable speed conveyor has a width dimension that is orthogonal to the conveyor's direction of rotation and wherein the geometric line defining the first and second sides is at the middle of the width dimension.

17. The oven of claim 1 further comprised of an air blower, which causes air to flow over portions at least one of the first and second sides of the conveyor.

18. The oven of claim 1 further comprised of an air blower, which controls food cooking by causing air to flow through a space within the oven that is between the top-mounted heaters and the conveyor.

19. The oven of claim 1 further comprised of a sprayer, which sprays a liquid above the conveyor.

20. The oven of claim 1 further comprised of a sprayer, which controls food cooking by spraying a liquid onto a food item on the conveyor.

21. The oven of claim 23, wherein the liquid is water.

22. The oven of claim 23, wherein the liquid is a cooking oil.

23. An oven comprising: a cavity having a top, a bottom, a first opening and a second opening; a single, variable-speed loop conveyor (conveyor) within the cavity, the conveyor extending between and moving food on the conveyor in a first direction that is from the first opening to the second opening, the conveyor having a first side and a second side, the first and second sides defined by a geometric line extending between, and substantially orthogonal to, the first and second openings; a first set of top-mounted heaters, the first set of top-mounted heaters directing infrared heat downwardly toward the first side of the conveyor; a second set of top-mounted heaters, the second set of top-mounted heaters directing infrared heat downwardly toward the second side of the conveyor; and a first bottom mounted heater which directs infrared heat upwardly toward the first and second sides of the conveyor; wherein the infrared heat output of each top heater is individually controllable.

24. The oven of claim 23 further comprised of at least one baffle between the first and second sets of top-mounted heaters, said baffle directing and reflecting heat from the first set of top-mounted heaters toward the first side of the conveyor and directing and reflecting heat from the second set of top-mounted heater toward the second side of the conveyor.

25. The oven of claim 23 wherein the heaters of at least one set of the first and second sets of top-mounted heaters are electrically-powered quartz heaters.

26. The oven of claim 23 wherein the heaters of at least one set of the first and second sets of top-mounted heaters are gas-fired heaters.

27. The oven of claim 23 the first bottom-mounted burner is an electrically-powered quartz heater.

28. The oven of claim 23 the first bottom-mounted burner is a gas-fired burner.

29. The oven of claim 23 wherein the first bottom-mounted heater directs infrared heat upwardly toward the first side of the conveyor and wherein the oven includes a second, bottom-mounted heater directing infrared heat upwardly toward the second side of the conveyor.

30. The oven of claim 23, wherein substantially more than fifty percent (50%) of the infrared heat energy from each heater in the first set of top-mounted heaters is directed to the first side of the conveyor and substantially more than fifty percent (50%) of the infrared heat energy from each heater in the second set of top-mounted heaters is directed to the second side of the conveyor.

31. The oven of claim 23 wherein the single variable speed conveyor has a width dimension that is orthogonal to the conveyor's direction of rotation and wherein the geometric line defining the first and second sides is at the middle of the width dimension.

32. The oven of claim 23 further comprised of an air blower, which causes air to flow over portions at least one of the first and second sides of the conveyor.

33. The oven of claim 23 further comprised of an air blower, which controls food cooking by causing air to flow through a space within the oven that is between the top-mounted heaters and the conveyor.

34. The oven of claim 23 further comprised of a sprayer, which sprays a liquid above the conveyor.

35. The oven of claim 23 further comprised of a sprayer, which controls food cooking by spraying a liquid onto a food item on the conveyor.

36. The oven of claim 34, wherein the liquid is water.

37. The oven of claim 34, wherein the liquid is a cooking oil.

38. The oven of claim 23, wherein for a first food item placed on first side of the conveyor and for a second food item placed along side the first food item but on the second side of the conveyor, for any conveyor speed, the total amount of heat energy input to the first food item by the first set of top-mounted heaters is different than the total amount of heat energy input to the second food item by the second set of top-mounted heaters, when said first and second food items move from the first opening to the second opening.

39. An oven comprising: a cavity having a top, a bottom, a first opening and a second opening; a single, variable-speed loop conveyor (conveyor) within the cavity, the conveyor having a width dimension and located between the first opening and second opening, the conveyor having first, second and third lanes that correspond to first, second and third segments of the conveyor's width; a first set of top-mounted heaters, mounted above the first lane and directing infrared heat downwardly toward the first lane of the conveyor; a second set of top-mounted heaters mounted above the second lane and directing infrared heat downwardly toward the second lane of the conveyor; a third set of top-mounted heaters mounted above the third lane and directing infrared heat downwardly toward the third lane of the conveyor; and at least one bottom mounted heater which directs infrared heat upwardly toward the first, second and third lanes of the conveyor; wherein the infrared heat output of each top heater is individually controllable such that the heat energy input to a first food item placed in the first lane of the conveyor at the first opening can receive different amounts of heat energy input to second and third food items placed in either of the second or third lanes but where food items placed alongside each other in the first, second or third lanes arrive at the second opening at the same time.

40. The oven of claim 39 further comprised of at least one baffle between each of the sets of top-mounted heaters, the baffle between each set directing and reflecting heat from the sets of top-mounted heaters toward corresponding conveyor lanes.

41. The oven of claim 39 wherein the top-mounted heaters are electrically-powered quartz heaters.

42. The oven of claim 23 wherein the top-mounted heaters are gas-fired heaters.

43. The oven of claim 39 wherein the at least one bottom mounted heater is an electrically-powered quartz heater.

44. The oven of claim 39 wherein the first bottom-mounted burner is a gas-fired burner.

45. The oven of claim 39 wherein the first bottom-mounted heater directs infrared heat upwardly toward the first lane of the conveyor and wherein the oven includes a second, bottom-mounted heater directing infrared heat upwardly toward the second lane of the conveyor and wherein the oven includes a third, bottom-mounted heater directing heat upwardly toward the third lane of the conveyor.

46. The oven of claim 39 further comprised of an air blower, which causes air to flow over portions at least one of the first, second and third lanes of the conveyor.

47. The oven of claim 39 further comprised of an air blower, which controls food cooking by causing air to flow through a space within the oven that is between the top-mounted heaters and the conveyor.

48. The oven of claim 39 further comprised of a sprayer, which sprays a liquid above at least one of the first, second and third lanes of the conveyor.

49. The oven of claim 39 further comprised of a sprayer, which controls food cooking by spraying a liquid onto a food item on the conveyor.

50. The oven of claim 49, wherein the liquid is water.

51. The oven of claim 49, wherein the liquid is a cooking oil.

52. The oven of claim 49, wherein for a first food item placed in the first lane, and for a second food item placed in the second lane and for a third food item placed in the third lane, said first, second and third items being placed adjacent to each other, for any conveyor speed, the total amount of heat energy input to the first food item is capable of being different than the total amount of heat energy input to either the second or third food items when said first, second and third food items move from the first opening to the second opening.

Description:

BACKGROUND

This invention relates to ovens used to cook foods. More particularly, this invention relates to high-capacity conveyor ovens, which are often used in restaurants and food service operations.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of a conveyor oven with multiple heating zones;

FIG. 2 is a top view of the interior of the oven shown in FIG. 1, taken through section lines 2-2;

FIG. 3 is a left side end view of the oven shown in FIG. 1;

FIG. 4 depicts an embodiment of electrical heaters used in various oven embodiments;

FIG. 5A is a schematic diagram showing how power control is achieved in one embodiment of the oven;

FIG. 5B is a schematic diagram of an electrical equivalent of the electrical heaters depicted in FIG. SA.

FIG. 5C depicts another embodiment of how power control is achieved in yet another embodiment;

FIG. 6A is a perspective view of the oven shown in FIG. 1 with the housing removed showing the placement of multiple top mounted heaters but also showing the placement of a bottom mounted heater;

FIG. 6B is a perspective view of the oven shown in FIG. 1 with the housing removed showing the placement of multiple top mounted heaters but also showing the placement of multiple bottom mounted heaters;

FIG. 7 is a left end view of the oven depicted in FIG. 1 with a heat deflecting/reflecting baffle mounted between the two top mounted heaters;

FIG. 8 is an end view of an alternate embodiment of the oven depicted in FIG. 1 showing two spatially-separated top-mounted heaters with a baffle between them and with liquid sprayers that dispense various liquids over foods on the conveyor in order to control cooking of various food items on the conveyor;

FIG. 9 is a left side end view of a conveyor oven with three separate cooking lanes, each of which has its own top and bottom mounted infrared heaters;

FIG. 10 is a side view of a multi zone conveyor oven shown in FIG. 9 having separately controllable top and bottom infrared heaters and but also having liquid dispensers along the conveyor path to effectuate cooking control of food items on the conveyor.

DETAILED DESCRIPTION

FIG. 1 shows a side view of a conveyor oven 10 with multiple heating zones. The oven 10 is comprised of a cavity 12 having a top 14, a bottom 16, a first opening 18 on the left side and a second opening 20 on the right side. A single, closed-loop, variable speed conveyor 22 extends between and passes through the first opening 18 on the left side and the second opening 20 on the right side and carries food items through the oven 10 in the direction shown by arrow 24. A controller 32, implemented with a microprocessor (not shown), memory (not shown) and control electronics (not shown) control the delivery of electric power and combustion gas and with a display 33 and input keypad 34

FIG. 2 shows a top view of the interior of the oven 10 shown in FIG. 1 taken through section lines 2-2. The conveyor 22 has a width, W, which is depicted in FIG. 2 as being divided into two sides that are identified by reference numerals 26 and 28 by a geometric center line 30. (The sides 26 and 28 of the conveyor 22 can also be considered to be zones, pathways, lanes or regions.)

The center line 30 of the conveyor 22 runs parallel to the conveyor's direction of travel 24 and orthogonal to the second openings 18 and 20. In the embodiment shown in FIG. 2, the first side 26 and the second side 28 are each one half the width W of the conveyor such that each of the sides' widths are equal to w/2 as shown. Alternate and equivalent embodiments include first and second sides 26 and 28 that are of unequal widths.

A salient aspect of the dual or split zones 26 and 28 of the conveyor 22 is that food items placed on either side 26 or 28 of the conveyor 22 at an input end of the oven 10 will arrive at the output end at substantially the same time, assuming of course they are placed side-by-side or adjacent to each other when they're in put to the oven. If the heat energy supplied to one side of the conveyor 22, is controlled vis-à-vis heat energy supplied to the other side of the conveyor 22, the time that different foods spend in the oven will be equal but their doneness when they exit the oven will be different or varied.

FIG. 3 depicts a left-side end view of the oven 10 depicted in FIG. 1 and FIG. 2. Two, side-by-side, electrically-powered top-mounted heaters 32 and 36 (end views of them shown) produce and direct infrared (IR) heat 33 downwardly toward areas of the conveyor 22 beneath them. Infrared heat 33 from the first or left-side top-mounted heater 32 is directed toward the first or “left” side 26 of conveyor 22. Infrared heat 37 from the second or “right” side top-mounted heater 36 is directed downwardly toward the second or “right” side 28 of the conveyor 22. In the embodiment shown in FIG. 3, a single bottom-mounted heater 38 directs infrared heat upwardly toward the conveyor 22 and toward the bottom of food items on the conveyor 22.

A food item placed on the left or first side 26 of the conveyor 22 such that it is beneath the first or left-side heater 32 will be cooked by heat energy coming from the bottom heater 38, but also by heat energy directed downwardly from the left-side heater 32. Similarly, a food item placed on the right or second side 28 of the conveyor 22 such that it is beneath the second or right-side heater 36 will be cooked by heat energy coming from the bottom heater 38, but also by heat energy directed downwardly from the left-side heater 36. The cooking of an item in the first side 26 can therefore be controlled and different from the cooking of an item in the second side 28 simply by controlling heat from the two separate top-mounted heaters 32 and 36.

In the embodiment shown in FIG. 3, a spatial separation of the first heater 32 from the second heater 36 helps to define two separate, i.e. multiple, heating lanes (also considered to be zones, pathways or regions) 26 and 28 due to the fact that most of the heat 33 from the first heater 32 will be directed onto a corresponding zone or area of the conveyor 22 directly below the first heater 32. Similarly, the infrared heat 37 from the second heater 36 will be directed substantially straight downwardly onto a corresponding area or region of the conveyor 22 immediately below the second heater 36. In alternate embodiments, such as those depicted in FIG. 7 and FIG. 8, the top mounted heaters 32 and 36 are substantially contiguous, owing to the fact that they use electric heating elements constructed as shown in FIG. 4.

FIG. 4 depicts an electric heating element used in embodiments of the conveyor oven 10 with multiple heating zones. The first or left side heater 32 is made up of boustrophedonic windings of electrically resistant wire or “cal rod” attached to a substantially planar and thermally-resilient substrate (not shown). The second or right side heater 32 is also made up of boustrophedonic winding of electrically resistant wire. It is important to note that the two windings of electrically-resitive wire that make up the left and right side heaters are connected in series with each other. In such an embodiment, the electrical resistance per unit length is the same, but the number of windings 41A in the first heater 32 is greater than the number of windings 41B in the second heater 36 and their spacing is closer. Since the number of windings in the side 32 is greater that the number of windings in the second side 36, and since the winding spacing is closer in the first heater 32 than in the second heater 36, the heat output from the first heater 32 is inherently greater than the infrared energy output from the second heater 36. Thus, by appropriately winding electrically resistant conductors, one of the heaters depicted in FIG. 3 is capable of having an infrared heat output level that is different from the infrared heat output level from the other heater. Those of ordinary skill in the art will recognize that while the windings depicted in FIG. 4 are boustrophedonic, crenellated windings could also be used as well as spiral or circular windings.

FIG. 5A depicts an end view of another embodiment of the oven shown in FIG. 1 wherein infrared output energy levels of the two, top-mounted heaters 32 and 36 are adjusted by a resistor 44 between power supply 42 and the second heater 36. FIG. 5B is a schematic diagram of the electrical equivalent circuit of the embodiment shown in FIG. 5A. The resistor 44 in series with the second heater 36, which is an electrically-resistive wire form a voltage divider with the voltage across the heater 36 being determined by the voltage drop across the resistor 44. For any energy source 42, the power dissipated by the second or right side heater 36 will be a function of its resistance and the resistance of the control resistor 44. By varying the value of resistor 44, the infrared energy level input to the second or right side 28 of the oven can be controlled with respect to the power level delivered to the left or first side of the oven 26.

FIG. 5C shows another embodiment of the 10 oven wherein the first and second top mounted heaters 32 and 36 generate different infrared output levels. The first top mounted heater 32 is driven by its own separately and individually controllable power supply 48. The second top mounted heater 36 is driven by its own power supply 50. The power supplies 48 and 50 are separately and individually controlled by a processor 52, which executes stored program instructions. The processor 52 also receives commands that are entered into a user interface 54 on the front panel of the oven 10 shown in FIG. 1.

In addition to separately and individually controlling IR from the top-mounted heaters 32 and 36, IR from the bottom heater 38 is also controllable through the CPU 52. In one embodiment the bottom mounted infrared heater 38 is gas fired. Infrared energy output from the bottom heater 38 is controlled by modulating the amount of gas supplied to a gas-fired heater, or, adjusting the electrical energy provided to a resistive heater.

FIG. 6A shows a perspective view of the oven 10 shown in FIG. 1 albeit with the cabinet removed in order to show the placement and orientation of multiple top mounted heaters 32 and 36 on both sides 26 and 28 of the conveyor 22. The top heaters identified by reference numerals 32A and 32B comprise a first set of top mounted heaters that direct infrared heat downwardly toward the conveyor 22 left or first side 26. The top heaters identified by reference numerals 36A and 36B comprise a second set of top mounted heaters that direct infrared heat downwardly toward the conveyor 22 right or second side 28. The bottom mounted heater 38, the width W′ of which is substantially equal to the width W of the conveyor, directs heat upwardly toward both sides of the conveyor 22.

In a preferred embodiment, the IR output from each heater 32A, 32B, 36A and 36B, and 38 shown in FIG. 6A is separately controllable by controlling the electrical power delivered to each heater. In an alternate embodiment, the left or first side heaters 32A and 32B are controlled together but their heat output is variable vis-à-vis the right or second side heaters 36A and 36B such that both left side heaters can be either increased or decreased relative to both right-side heaters.

FIG. 6B shows yet another embodiment, wherein the sets of top mounted heaters are separately and individually controlled, however, in FIG. 6B, several bottom-mounted heaters 38 are provided. In one embodiment, each of the bottom-mounted heaters is individually controllable with respect to the others. In another embodiment, the left side, bottom-mounted heaters (one shown and identified by 38A) are controlled together with respect to the right-side bottom-mounted heaters (two shown, identified by reference numerals 38B and 38C).

The foregoing figures depict conveyor ovens with multiple heating zones 26 and 28, which are effectuated by multiple top-mounted heaters that direct IR downwardly and onto an area directly below the heaters. One or more bottom-mounted heaters direct IR upwardly. By controlling or varying the IR delivered to the different sides of the conveyor, the cooking that occurs on one side of the conveyor will be different than the cooking that occurs on the other side of the conveyor to thereby provide a conveyor oven with multiple cooking/heating zones.

Those of ordinary skill in the art know that infrared energy is a form of electromagnetic energy. It will therefore disperse as it travels from the heaters toward the conveyor. Since the IR disperses as it travels from the heaters, at least some of the IR emitted from a top mounted heater in one zone will reach one or more other zones. Experimentation revealed that more than 50% of the IR from a top mounted heater reached the conveyor area directly below the heater, with the balance being lost to adjacent spaces. Experimentation also showed that the thermal separation of the two zones 26 and 28 can be effectively improved (and less heat directed to adjacent zones) more cooking differences between the two zones 26 and 28 significantly enhanced by the use of a baffle 60 located between the heaters to deflect and/or reflecting IR emitted from one heater. The baffle 60 is believed to cut off the IR waves that disperse from the heater toward adjacent zones.

The baffle 60 is preferably a relatively rigid stainless steel panel or vane that extends downwardly from the top 14 of the oven 10. The further that the baffle 60 extends downwardly the greater will be its separation effect. Extending the baffle 60 downwardly all the way to the conveyor 22 will completely separate the IR emitted from the top mounted heaters, however, a baffle that extends from the oven top 14 to the conveyor might limit the types of foods that the oven can accommodate.

Additional experimentation revealed that the reflection and deflection effectuated by the baffle 60 varies by the angle θ formed between the baffle 70 and a line normal to the oven's top surface 14. When the baffle 60 is at an angle θ, relative to the plane of the top 14, the baffle effectively directs and reflects infrared heat from the second heater 26 toward the second or right side zone 28 such that substantially less than 50% of the IR heat output from the second heater 36 reaches the first side 26 of the conveyor 22. It is believe that the baffle 60 effectuates greater thermal separation between the first zone 26 and the second zone 28.

In the embodiment of the element shown in FIG. 6B, additional thermal separation between the two zones or lanes 26 and 28 by using at least one bottom-mounted baffle 61.

FIG. 8 shows yet another end view of the oven depicting the first zone 26. One or more liquid dispensers or sprayers 64 and 66 dispense (e.g., spray or mist) a liquid 70 onto food items placed on the conveyor belt 22 in order to vary cooking time. In one embodiment, the dispensers 64 spray water, cooking oil, seasonings or air, as the food items enter the oven. Dispensing water or a cooking oil onto food items necessitates more input heat energy in order to cook a food item. Dispensing any form of liquid, whether gas or solid, can significantly affect the cooking process that takes place in the oven 10 because oil, water or heat will require the absorption and dissipation of heat provided by the heaters. Dispensing liquids can thereby slow the cooking process.

In one embodiment, the liquid dispensed into the conveyor oven is high pressure air, which effectuates a temperature drop or cooling over one or both of the conveyor zones. The liquid can also be oil, water, or solutions of seasonings or a combination thereof.

FIG. 9 depicts yet another embodiment of a conveyor oven with multiple cooking zones. Food items can be placed in three separate zones or lanes, which are identified by reference numerals 26, 28, and 76 to be cooked by corresponding first, second and third sets of top-mounted infrared heaters identified by reference numerals 32, 36 and 74 respectively. In the embodiment shown in FIG. 9, the heaters of each set of top mounted heaters, are individually controllable with respect to each other. Each heater directs infrared energy downwardly onto a corresponding area of the conveyor 22 directly beneath each heater. Top mounted baffles 60A and 60B separate the top mounted heaters from each other but also separate the infrared heat emitted from each heater by reflecting and directing infrared heat from adjacent heaters, downwardly to thereby provide greater control.

The first, second and third lanes 26, 28 and 76 are further defined by separate individually controlled bottom heaters 38A, 38B, and 38C. The bottom heaters can also be separated by baffles to further direct and reflect infrared energy emitted from them.

In FIG. 9, each of the lanes 26, 28 and 76 is substantially equal in width. Alternate embodiments would of course include different widths with respect to each other.

By providing separate and individually controllable top mounted infrared heaters and separate and individually controllable bottom mounted heaters, the amount of heat energy input to food items in each of the lanes 26, 28 and 76, can be varied to effectuate a different doneness to food items in each of the food lanes. Food items cooked in one lane can be cooked differently than food items in a different lane with the food items in each lane arriving at the output side of the oven at the same time.

By way of example, if the infrared energy output from the heaters in the first lane 26, is greater than the infrared energy output from the heaters in the third lane 76, identical or substantially identical food items placed in first and third lanes at the conveyor input end, will be cooked differently as they pass through the oven 10. The food item cooked in the first lane will be more well done, i.e., cooked more, than the food item in the third lane but both food items will arrive at the output or right end 20 at the same time.

The conveyor oven 10 with multiple heating zones depicted in the figures and described and claimed herein provides significant advantages over prior art conveyor ovens, especially to restaurants and food services that provide made-to-order foods. Three people, who dine together at a restaurant and who each order steaks, but who prefer them cooked rare, medium and well, can have their steaks cooked to match their preferences but with each party's steak being ready to be served at the same time. Different constituents of a food item, such as a toasted sandwich, and which require different levels of cooking but which should also be ready at the same time, can be easily prepared and their cooking concluded simultaneously using the conveyor oven with multiple heating zones.

FIG. 10 is a side view of another embodiment of a multi zone conveyor oven. In FIG. 10, additional cooking control is accomplished by multiple liquid dispensers 66A, 66B and 66C, which are distributed lengthwise along the conveyor 22 and which dispense liquids such as air, water or cooking oil or seasonings onto food items as they pass through the oven 10.

In the embodiments shown in each of the figures the top mounted heaters were electrically powered quartz heaters. In one embodiment the top mounted heaters are identical in that they use a substantially baustrophodontic electrically resistant wire the number of windings and spacing of which are identical on each side or in each zone. In an alternate embodiment, the number of windings is greater and the spacing is narrower as shown in FIG. 4 with a fixed power level applied to both sides. In yet a third embodiment, the power control resistor can be used between a power supply source and one of the heaters to effectuate power control.

In the embodiments described above, the top-mounted heaters are electrically powered whereas the bottom-mounted heaters are gas fired. In an alternate embodiment, either of the top and bottom mounted heaters, or both can be gas fired heaters such as the gas fired heater disclosed in the inventors' co-pending patent application, the U.S. serial number of which is, Ser. No. 11/692,465, and which is entitled, Infrared Emitting Gas Burner, the teachings of which are incorporated by reference herein in their entirety. The ability to control or provide different amounts of heat energy to different food items traveling on the same conveyor allows for variable cooking control of different food items used in the same food product or service.

The description and embodiments set forth above are for purposes of illustration and not limitation. The appurtenant claims define the scope of the invention disclosed herein.