Conveyor type oven

A conveyor type oven (10) for processing food products (32) and a method of use that includes heating sections and/or zones, each of the heating sections/and or zones being individually temperature controlled. The conveyor type oven (10) comprises an oven housing (12) forming an oven cavity (14), the oven housing (12) having an inlet opening (16) and an exit opening (18) each in communication with the oven cavity (14), a conveyor system (20) disposed through the inlet opening (16), the oven cavity (14), and the exit opening (18) for transporting food products (18) through the oven cavity (14) for processing the transported food product (32), a first heating section (22) forming a first heating zone (38) disposed within the oven housing (12) positioned on one side of the conveyor (20), the first heating section (38) includes a first type of radiant heat emitter (36) focusing radiant heat toward the conveyor (20); a second heating section (24) disposed within the oven housing and positioned on an opposing side of the conveyor (20) from the first heating section (22), the second heating section (24) may include an inlet heating zone (44) and an outlet heating zone (46), each of the inlet and outlet heating zones having a second type heat emitter (40) substantially focusing radiant heat toward the conveyor (20), and a temperature control system (26) connected to the heat emitters (36, 40) of the first heating zone (38), the inlet heating zone (44), and the outlet heating zone (44) in a manner to monitor and selectively control the temperature of each heating zone separately from the temperature control of the other heating zones.

FIELD OF THE INVENTION

The present invention relates in general to ovens and more specifically to a conveyor type oven for reheating, toasting, and/or cooking food products.

BACKGROUND

Conveyor type ovens have been used for many years in commercial enterprises for heating and/or cooking food items. Conveyor type ovens include a conveyor for transporting food products through the oven. The oven often has one or more heating elements spaced about the conveyor for heating the oven cavity and the food product passed therethrough. These prior art ovens rely on high velocity hot air, infrared, radiant, or convection type heating elements to treat the food products passing through the oven.

A drawback with the prior art conveyor type ovens is the wasted energy produced in reheating, toasting, or cooking of the food product. Often the prior art conveyor type ovens utilize a round bar type emitter that emits infrared waves in at least a 180 degree arc thereby heating the entire oven cavity and limiting the emissions directed toward the conveyor and the carried food product. Another drawback of the prior art conveyor type ovens is that the heating elements of the oven are controlled to maintain a constant air temperature within the oven cavity. Therefore, when a cold or frozen food is introduced into the oven on the conveyor the heating elements are charged to maintain a set air temperature in the oven cavity. This adjustment in the temperature of all of the heating elements wastes energy and increases the cost of operation of the oven and often results in an unacceptable food product.

It is thus a desire of the present invention to provide a conveyor type oven that provides desired heating, cooking, or toasting of a food product in an expedited manner while limiting energy consumption. It is a further desire to provide a conveyor type oven that includes a first heating section located on a first side of the conveyor that focuses energy substantially toward the conveyor, and a second heating section located on a second side of the conveyor that directs energy substantially toward the conveyor. It is a further desire for the second heating section to be divided into two separate zones wherein each zone includes at least one heating element that is controlled to maintain a set surface temperature separate from the other heating zones. It is a still further desire to provide a conveyor type oven that includes a plurality of heating zones wherein each heating zone includes independent heating elements that are operated to maintain a substantially constant temperature within the heating zone.

SUMMARY OF THE INVENTION

In view of the foregoing and other considerations, the present invention relates to conveyor type ovens for heating, toasting, or cooking food products.

It is a benefit of the present invention to provide a conveyor type oven having a first heater section including a heat emitter of a first type positioned on one side of a conveyor and a second heater section having heat emitters of a second type positioned on the opposing side of the conveyor.

It is a further benefit of the present invention to provide a conveyor type oven wherein the heat emitting elements substantially focus the emitted energy toward the conveyor and carried food product.

It is a still further benefit of the conveyor type oven of the present invention to provide a plurality of heating zones, each heating zone including at least one heat emitting element that is controlled to maintain a substantially constant surface temperature.

Accordingly, a conveyor type oven for processing food products and a method of use is provided that includes heating sections, each of the heating sections being individually temperature controlled, and wherein each of the heating sections may include independently controlled heating zones. The conveyor type oven of the present invention comprises an oven housing forming an oven cavity, the oven housing having an inlet opening and an exit opening each in communication with the oven cavity, a conveyor system disposed through the inlet opening, the oven cavity, and the exit opening for transporting food products through the oven cavity for processing the transported food product, a first heating section forming a first heating zone disposed within the oven housing positioned on one side of the conveyor, the first heating section including a first type of radiant heat emitter focusing radiant heat toward the conveyor; a second heating section disposed within the oven housing and positioned on an opposing side of the conveyor from the first heating section, the second heating section having an inlet heating zone and an outlet heating zone, each of the inlet and outlet heating zones having a second type heat emitter directing radiant heat therefrom substantially toward the conveyor, and a temperature control system connected to the heat emitters of the first heating zone, the inlet heating zone, and the outlet heating zone in a manner to monitor and selectively control the temperature of each heating zone separately from the temperature control of the other heating zones.

A method of processing food products is provided comprising the steps of transporting a food product through an oven cavity for processing, emitting radiant heat from a first heating zone toward the food product within the oven cavity, wherein the radiant heat is emitted from a first type of heat emitter, emitting radiant heat from an inlet heating zone toward the food product within the oven cavity, wherein the radiant heat is emitted from a second type of heat emitter, emitting radiant heat from an outlet heating zone toward the food product within the oven cavity, wherein the radiant heat is emitted from a second type of heat emitter, and controlling the temperature of each of the first heating zone, the inlet heating zone, and the outlet heating zone individually.

DETAILED DESCRIPTION

FIG. 1is a representative view of a conveyor oven of the present invention generally designated by the numeral10. Conveyor oven10includes an oven housing12forming an oven cavity14having an inlet opening16and an exit opening18, a conveyor20, a first heating section22, a second heating section24, a temperature control system26, a conveyor speed control28, and an on/off switch30.

Oven housing12is constructed of material familiar to those skilled in the art forming an oven cavity14. Oven housing12includes an inlet opening16and an exit opening18in communication with oven cavity14. A conveyor20extends through inlet opening16, oven cavity14, and exit opening18. Conveyor20is a device such as a belt or chain driving device that moves items such as food product32(FIG. 2) along conveyor20and through oven cavity14. Oven housing12further includes heating sections22and24for treating food product32carried on conveyor20through oven cavity14.

Oven housing12may further include adjustable heat shields34movably positioned proximate inlet and exit openings16and18. Heat shields34may be provided to maintain heat and infrared radiation within oven cavity14. Heat shields34may be adjustable to define the size of inlet and/or exit openings16and18relative to food product32passing through oven cavity14.

Oven housing12further includes first heating section22and second heating section24. The first heating section22and the second heating section24are positioned within oven housing12on opposing side of conveyor20. For descriptive purposes, first heating section22is positioned below conveyor20and second heating section24is positioned above conveyor20. Pursuant to the invention the first and second heating sections22and24may be reversed in relation to conveyor20. Heating sections22and24include heating elements that focus heat energy toward conveyor20within oven cavity14.

FIG. 2is a representative view of conveyor oven10of the present invention along the line I—I ofFIG. 1revealing first heating section22. First heating section22comprises a flat-bar, infrared emitter36. Emitter36may comprise a single heating element or numerous heating elements. Heat emitter(s)36and first heating section22may extend substantially along the length of oven cavity14. First heating section22forms a first heat zone38that is controlled by temperature control system26that is shown and described in further detail in relation toFIGS. 1 and 4.

FIG. 2Ais a representative view of a flat bar heat emitter36of the present invention. Emitter36may be a flat bar sheathed heat emitter having exposed resistance wires or coils. As shown, flat bar emitter36focuses infrared heat, as indicated by the arrows, toward food product32that is carried by conveyor20(FIGS. 1 and 2). Temperature control of heat emitter36, and thus first heat zone38, facilitates controlled processing of food product32.

FIG. 2Bis a representative view of a round type heat emitter37commonly utilized in the prior art conveyor type ovens. As shown by the arrows, infrared heat emitted from round type heater emitter37is directed in at least an arc of approximately 180 degrees. This distribution of emitted infrared heat increases energy use and the associated costs while failing to focus the desired emitted energy toward food product32.

FIG. 3is a representative view of conveyor oven10of the present invention along the line II—II ofFIG. 1revealing second heating section24. Second heating section24includes heat emitters40that are a second type of heat emitter of a type different from first section emitter36(FIG. 1). Heat emitters40may be a ceramic emitter having a heating wire (not shown) embedded therein. Ceramic emitters40are concave shaped having a concave face42that focuses infrared energy toward conveyor20(FIG. 1) and the carried food product. An example of ceramic emitter40is an emitter that provides watt densities from approximately 6 watts per square inch to 39 watts per square inch, wavelengths from approximately 2 to 7 micrometers, and temperatures up to approximately 700 degrees centigrade.

Second heating section24is divided into at least two heating zones. As shown inFIG. 3, heating section24includes an inlet heating zone44and an outlet heating zone46, each zone44and46having at least one heat emitter40. In relation toFIG. 1, inlet heating zone44is positioned proximate inlet opening16and outlet heating zone46is positioned proximate exit opening18.

Each of the heating zones44and46of heating section24includes one or more ceramic heat emitters40. The number of heat emitters40provided in each heat zone is a design choice related to the size of the oven cavity and the desired throughput of food products. Each heating zone44and46is independently controlled via temperature control system26further described in relation toFIG. 4.

FIG. 4is a block diagram of a temperature control system26of the present invention. Temperature control system26includes a digital controller48, solid-state relays50, and temperature sensors52. Temperature sensors42may be a thermocouple functionally connected to emitters36and/or40so as to detect the temperature of the surface or face42of the emitter and/or the temperature proximate the emitter. Temperature control system26facilitates control of each heating zone38,44, and46without regard to the ambient temperature of oven cavity14(FIG. 1).

Each heating zone38,44, and46is connected to a digital controller48for providing a set point temperature for each of the heating zones. Temperature control system26further includes an individual heat sensor52in functional connection with each heat zone and the associated emitters36or40and controller48via an individual solid state relay50. Temperature sensors52are positioned so as to substantially detect the temperature of the proximate heat emitter and thus facilitate control of the temperature of the heat emitter and associated heat zone as opposed to adjusting the temperature of the heat emitters in relation to the ambient temperature of the oven cavity.

A method of operation of the present invention is described in relation toFIGS. 1 through 4. A food product32is selected for processing through oven10. An appropriate temperature and pass through time is selected for processing food product32. An operator turns oven10on, sets a conveyor speed for passing product32through oven10, and temperature control system26is set to the desired temperature for the particular food product32.

Digital controller48may be programmed so that first heating zone38has a first set point temperature and the inlet and outlet heating zones44and46are programmed at a second set point temperature. As should be realized, each heating zone is defined as an area proximate the heat emitters for each section, the heat zone may be monitored and controlled by sensing the temperature of the surface of the heat emitter(s). Control system26operates to maintain each of the heating zones38,44, and46at the assigned set point temperature.

Food product32is placed on conveyor20so as to be introduced and carried through oven cavity14. As food product32, often cold or frozen, enters oven cavity14inlet heating zone44is controlled through digital controller48to maintain the temperature of heating zone44. As food product32continues through oven cavity14, outlet heating zone46reacts as necessary through digital controller48to maintain a constant temperature. Due to the initial heat maintenance by inlet heat zone44, first heat zone38and outlet heat zone46do not require substantial temperature adjustment to sustain a selected set temperature, thus reducing energy consumption and providing for consistent quality of processing of food product32. Additionally, the focused emission of infrared energy from emitters36and40toward conveyor20and food product32eliminates excess heat production for the purpose of heating oven cavity14as in the prior art conveyor ovens.

From the foregoing detailed description of specific embodiments of the invention, it should be apparent that a conveyor type oven and method that is novel has been disclosed. Although specific embodiments of the invention have been disclosed herein in some detail, this has been done solely for the purposes of describing various features and aspects of the invention, and is not intended to be limiting with respect to the scope of the invention. It is contemplated that various substitutions, alterations, and/or modifications, including but not limited to those implementation variations which may have been suggested herein, may be made to the disclosed embodiments without departing from the spirit and scope of the invention as defined by the appended claims which follow. For example, various materials of construction may be made, varying numbers and arrangement of heating zones in the heating sections are contemplated by the invention, and variations in the manner of sensing controlling the temperature of the emitters and heat zones may be made.