Conveyor oven with multiple heating zones

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.

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.