Abstract:
An oven having one or more independently adjusted radiant heaters that can be dynamically adjusted before and during a curing or heating process to account for the shape and size of an object being cured or heated, further comprising a means for dynamically controlling the level of heat output from the radiant heaters. The oven preferably has radiant heaters positioned on opposing sides of the object and one or more back panels positioned behind the radiant heaters to absorb any radiant heat that misses the object. The oven of the present invention also has a turbulent fan and a means for deflecting the air flow of the convection heat throughout the internal oven chamber and toward the object. In addition, the oven has an exhaust fan that can discharge the exhaust either outside of the oven or redirect the exhaust back into the oven chamber to raise the ambient temperature, depending on the application for which the oven is being used. A computer system uses one or more object sensors and ambient sensors to control the radiant heaters (both position and level of heat output), the turbulent fan, the exhaust fan, and water flow to the object sensor. The oven of the present invention combines three different types of method of heating: convection, ambient, and radiant. +

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of Application No. 60/163,503, filed Nov. 4, 1999. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to ovens, and more specifically, to ovens using independently controlled radiant heaters, both position and levels of heat output, with the optional combining of different methods of heating including ambient, convection, and radiant heat. 
     2. Related Art 
     Conventional curing ovens typically use one of three methods of heat transfer: convection, ambient, or radiant. Regarding the use of radiant heaters, such curing ovens typically use only one radiant heater which is locked in a fixed position. That is, the radiant heater is not dynamically movable to adjust the direction of the radiant heat emitted from the heater nor is the level of heat output from the radiant heater dynamically controlled. This results in an inefficient means for curing an object because the maximum effect of the heater cannot be customized or adjusted for different shaped objects being cured or for objects combining different compositions. 
     For example, in U.S. Pat. No. 5,836,085 to Ben-Ezra, an improved paint-spraying and curing booth is disclosed having direct fired U-tube radiant heaters. The radiant heaters are built into the radiant heating system, thereby being fixed in position. The radiant heaters are not movable or adjustable. Therefore, regardless of the size or shape of an object placed within the paint-spraying and curing oven, the radiant heaters will emit heat in the same direction and at the same angle every time. The same problem exists with the ovens disclosed in U.S. Pat. No. 5,588,830 to Josefsson, et al., and in U.S. Pat. No. 5,205,273 to Sparks, et al. 
     Therefore, there is a need for an oven having one or more radiant heaters that are dynamically movable such that the radiant heaters can be adjusted to maximize the efficiency of the emitted heat according to the size and/or shape of an object being cured/heated within the oven. There is a further need for an oven in which the levels of heat output from the radiant heaters can be dynamically controlled during the curing/heating process. 
     In addition to using fixed radiant heaters, a conventional curing oven may also combine two different methods of heat transfer, but there does not exist a curing oven that combines all three methods of heating. In the ′830 Patent to Josefsson, et al., a combined radiant and convention heating oven is disclosed wherein the convection air is controlled independent of the radiant heat surfaces. The convection air is circulated via a plurality of fans that are controlled by a plurality of frequency motor drive units. The temperature of the radiating surfaces are controlled by heated air flowing through ducts extending longitudinally through the oven that abut the radiating surfaces. Optionally, dampers may be incorporated into the ducts to provide individual control to each radiating surface. An important feature of the Josefsson oven is the placement and use of a temperature sensor. The temperature sensor is placed in a return plenum to determine the convection air temperature. This temperature is then input into a control device which uses the convection temperature to control the speed of the fans and the amount of fuel supplied to the burners. 
     There are several disadvantages to the Josefsson heating oven, but the principal problem is the temperature sensor. By placing the temperature sensor in a location, e.g., the return plenum, for determining the convection air temperature, the object being cured can easily be either under-baked or over-baked. When an object, having bolts or the other components attached thereto, is under-baked, the paint will flake when a bolt is removed. When an object is over-baked, the paint becomes discolored. 
     Therefore, there is a need for a curing oven that combines ambient, convection, and radiant methods of heating that ensures a constant and uniform temperature of the object during the curing process. 
     SUMMARY OF THE INVENTION 
     The present invention is an oven having independently movable radiant heaters, wherein the levels of heat output from the radiant heaters also are dynamically controlled, and that optionally combines three types of heat: convection, ambient, and radiant. The oven comprises one or more adjustable U-Tube radiant heaters on each side of the internal oven chamber. The radiant heaters can pivot horizontally toward the object being heated as well as pivot vertically to direct the focus of the heaters, thereby taking into account the shape and size of the object. One or more back panels, preferably colored flat black, are positioned behind the radiant heaters to capture any radiant energy emitted from the radiant heaters that misses the object. 
     The oven of the present invention is directed to a curing oven being used for the powder based paint curing of an object; however, this is for convenience purpose only. The oven of the present invention can be adapted for use in pre-baking, baking, or drying-off an object, or in any other oven application requiring the heating of an object. 
     In the present invention, the oven can discharge the heat exhaust from the radiant heaters to either outside of the oven or back within the oven chamber, depending on the object being heated and the type of heating application, to help reach a maximum ambient temperature. This results in achieving ambient temperatures of 300-500 degrees much faster. 
     A conventional turbulent fan may be positioned on the top or side of the oven that works in combination with an air direction unit and a means for deflecting the airflow to circulate air within the oven chamber. The preferred means for deflecting airflow is one or more deflectors positioned along the walls of the oven chamber. The use of deflectors is beneficial to the heating process because they reduce dust build-up and are easier to clean than conventional duct work. 
     The radiant heaters, turbulent fan (convection heat), and ambient temperature (managed via the radiant heaters, exhaust fan and back panels) are all controlled by a computer system connected to one or more temperature sensors monitoring the temperature of the object being cured and the ambient temperature within the oven chamber. There are many advantages to the oven of the present invention. By dynamically controlling the position, direction, and level of heat (turning on and off) of the radiant heaters, the time needed to cure/heat an object is greatly reduced. The cure time is also improved due to the combination of convection, ambient, and radiant methods of heat. The following table illustrates sample test data for curing 14 gauge steel according to the present invention: 
     
       
         
               
               
               
             
               
               
               
             
           
               
                   
                   
               
               
                   
                 Method of Heating 
                 Time to Cure (Minutes) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Ambient only 
                 40 
               
               
                   
                 Ambient + Radiant 
                 20 
               
               
                   
                 Ambient + Radiant + Convection 
                 6 
               
               
                   
                 (Present Invention) 
               
               
                   
                   
               
             
          
         
       
     
     A curing oven of the present invention also requires much less fuel during operation. For example, a thirty (30) minute test using the present invention requires only 1/10th of a cubic foot of gas to maintain a proper cure. In addition, the curing oven of the present invention can be used with either powder based or water based paint. The curing oven also eliminates the majority of the EPA and OSHA problems associated with conventional spray painting of objects. 
     The oven of the present invention also maximizes the use of radiant heaters by allowing the radiant heaters the ability to pivot toward the object being cured or heated. In the preferred embodiment, the radiant heaters can pivot to within 6″ of the object as well as pivot vertically the direction of the emitted heat. The position of the radiant heaters also are adjusted dynamically during the entire curing/heating process, thereby ensuring proper curing at all times. 
     Furthermore, this pivoting of the radiant heaters and dynamic control of the level of heat from the radiant heaters provides the means for proportionally curing or heating an object from top to bottom. That is, the heating of an object can be customized according to the composition of the object. To properly cure an object, one portion, e.g., the bottom, may require slower cure time than another portion, e.g., the top, of the object, such as if the two portions were made from different gauges of steel. Therefore, to enable the object to be cured within the same time frame, thereby ensuring a proper and uniform cure, the radiant heaters may be controlled such that the bottom portion of the object cures at a lower temperature (and slower) than the top portion. In this example, one or more radiant heaters may be farther away from the bottom portion of the object and directed to a lower level of heat, whereas one or more other radiant heaters may be moved in closer to the top portion of the object and directed to a higher level of heat, resulting in the top and bottom portions of the object completing the cure process at the same time. 
     Lastly, one or more temperature sensors of the present invention is used to measure the temperature of the object being cured as well as the ambient temperature within the oven chamber. This is an important distinction over the prior art in that the prior art typically measures only the ambient temperature within the curing oven, and the temperature of an object being cured is always higher than the ambient and convection temperatures. Therefore, conventional curing ovens improperly heats an object resulting in the object being overbaked or underbaked. In contrast, by measuring the temperature of the object being cured, the object will never be incorrectly cured. 
    
    
     BRIEF DESCRIPTION OF THE FIGURES 
     The present invention is described with reference to the accompanying drawing. In the drawing, like reference numbers indicate identical or functionally similar elements. Additionally, the left-most digit of a reference number identifies the drawing in which the reference number first appears. 
     FIG.  1 : A planar cross sectional view of an oven of the present invention showing the preferred means for heating using radiant heat; 
     FIG.  2 : A planar cross sectional view of the oven showing the heating of an object; 
     FIG.  3 : A planar front view of panel A of radiant heaters; 
     FIG.  4 : A planar front view of panel B of radiant heaters; 
     FIG.  5 : A planar front view of a framework for mounting panel B of radiant heaters; 
     FIG.  6 : A planar front view of an oven of the present invention with a turbulent fan; 
     FIG.  7 : A block diagram of an exemplary computer system for use with the oven; 
     FIG.  8 : A data flow diagram showing the operation of the oven controller software of the present invention; 
     FIG.  9 : A control flow diagram showing the main operation of the curing oven controller software; 
     FIG.  10 : A control flow diagram showing the operation of the Control Curing Oven software; 
     FIG.  11 : A control flow diagram showing the operation of the Check Ambient Temp software; 
     FIG.  12 : A control flow diagram showing the operation of the Turn Off Radiant Heaters software; 
     FIG.  13 : A control flow diagram showing the operation of the Check Radiant Heaters software; 
     FIG.  14 : A control flow diagram showing the operation of the Check Turbulent Fan software; 
     FIG.  15 : A block diagram showing the main screen of the user interface for the Curing Oven Controller software; 
     FIG.  16 : A block diagram showing the display screen of the user interface for the Oven Start/Stop/Monitor process; 
     FIG.  17 : A block diagram showing the display screen of the user interface for the Oven Exhaust Fan process; 
     FIG.  18 : A block diagram showing the display screen of the user interface for the Oven Heater Control process; 
     FIG.  19 : A block diagram showing the display screen of the user interface for the Infrared Water Pump Sensor process; 
     FIG.  20 : A block diagram showing the display screen of the user interface for the Oven Process Parameters; 
     FIG.  21 : A graphical representation of results for Test 1 using the oven of the present invention; 
     FIG.  22 : A graphical representation of results for Test 2 using the oven; 
     FIG.  23 : A graphical representation of results for Test 3 using the oven; and 
     FIG.  24 : A graphical representation of results for Test 4 using the oven. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     I. The Curing Oven 
     All dimensions used in the preferred embodiment are for convenience purpose only. It would be readily apparent to one of ordinary skill in the relevant arts to design and build an oven of the present invention using different dimensions and comparable components. It also is believed that the oven of the present invention is described in sufficient detail such that one of ordinary skill in the relevant art can design, manufacture, and use such an apparatus. Furthermore, the oven of the present invention is described in terms of a curing oven for curing a painted object, but this is for convenience purposes only. The oven of the present invention, and all of its features, can be used for any purpose, including, but not limited to pre-baking, baking, drying-off, curing, and heating an object. 
     A. Structure 
     FIG. 1-5 show the preferred embodiment of a cross section of an oven  100  of the present invention, while FIG. 6 shows the oven  600  with a turbulent fan  602 . The oven  100  comprises an oven chamber  102  having a top  104 , a first side wall  106 , a bottom  108 , a second side wall  110 , a front wall and a back wall. In the preferred embodiment, the oven  100  is made of steel and is about 8′×8′×40′, but it would be readily apparent for one of ordinary skill to build an oven  100  of the present invention to any dimensions. The oven chamber  102  is a closed-door cabinet having a double-door on opposing sides of the oven  100 , such as a first double door on the front wall and a second double door  112 ,  114  on the back wall, to allow for an assembly line application to be achieved for curing/heating an object  202 . That is, an object  202  to be cured or heated is suspended by a central rail  116  and is moved through a first set of double-doors and into the oven chamber  102  of the oven  100 . After the curing/heating of the object  202  is complete, the second set of double doors  112 ,  114  are opened and the object  202  is moved through the double doors  112 ,  114  and out of the oven  100 . One or more doors  112 ,  114  may incorporate a viewing window to allow a user to observe an object within the oven chamber  102 . The number and placement of doors  112 ,  114  is for convenience only. The oven  100  of the present invention can be designed and manufactured with any number of doors  112 ,  114  and placement of such doors  112 ,  114 . 
     In the preferred embodiment, there are three radiant heaters  120   a-c  positioned on the first side wall  106  and three radiant heaters  120   d-f  positioned on the second side wall  110  of the oven  100 , wherein the radiant heaters  120   a-f  are vertically aligned. Each set of radiant heaters has a top radiant heater  120   a,d ; a middle radiant heater  120   b,e ; and bottom radiant heater  104   c,f.    
     The present invention incorporates conventional U-tube radiant heaters  120   a-f  that are uniquely mounted; that is, each radiant heater  120   a-f  is pivotally mounted to a radiant heater support bar  118   a,b  such that the radiant heaters  120   a-b  pivot about two points. The mounting is described in reference to a single radiant heater, such as top radiant heater  120   a  for convenience purpose only. It is equally applicable to all of the radiant heaters  120   a-f.    
     First, the top radiant heater  120   a  is pivotally mounted to an L-shaped bracket  122   a , resulting in the top radiant heater  120  being able to pivot about a central point in relation to the L-shaped bracket  122   a  such that the heat emitted from the top radiant heater  120   a  moves in a vertical plane as the top radiant heater  120   a  is pivoted. Second, the L-shaped bracket  122   a  is pivotally mounted to a radiant heater support bar  118   a , resulting in the L-shaped bracket  122   a  being able to pivot in relation to the radiant heater support bar  118   a  such that the top radiant heater  120   a  moves in a horizontal plane toward and away from the object  202 . 
     In operation, the L-shaped bracket  122   a  of the top radiant heater  120   a  is swung toward or away from an object  202  being cured/heated, then the top radiant heater  120   a  itself can be pivoted around the L-shaped bracket  122   a  to point its heat directly at the object  202  or a portion thereof This provides a means for moving each of the radiant heaters  120   a-f  to cure/heat a specific portion of the object  202 . An L-shaped bracket  122   a  is used for convenience purpose only. It would be readily apparent for one of ordinary skill in the relevant art to use a comparable means for pivotally mounting the radiant heaters  120   a-f  In the preferred embodiment, the radiant heaters  122   a-f  are conventional and commercially available U-Tube radiant heaters. 
     To provide for this means for moving the radiant heaters  120   a-f , the blower units  304 ,  306 ,  404 ,  406  of the radiant heaters  120   a-f  must be rotatably connected to the radiant heaters  120   a-f . In conventional curing ovens, a conventional radiant heater is rigidly connected to a blower unit, thereby preventing the rotation of the radiant heater in relation to the blower unit. In contrast, the present invention uses a new coupling between a blower unit and a radiant heater. 
     For example, in the first set of radiant heaters  120   a-c , shown as panel A on FIG. 2, the top radiant heater  120   a , having a top U-tube  308   a , and middle radiant heater  120   b , having middle U-tube  308   b , are rotatably connected to a first blower unit  304  while the bottom radiant heater  120   c , having bottom U-tube  308   c , is rotatably connected to a second blower unit  306 . Referring to the top U-tube  308   a  of the top radiant heater  308   a , the exhaust end  312  of the top U-tube  308   a  is secured to a first coupler  316  that fits within, and is rotatable in relation to, a second coupler  314  attached to the first blower unit  304 . The use of a rotatable first coupler  316  and second coupler  314  are well known in the relevant arts. It would be readily apparent for one of ordinary skill in the relevant art to use such a first coupler  316  and second coupler  314 . Similar to the top U-tube  308   a  of the top radiant heater  120   a , the middle U-tube  308   b  of the middle radiant heater  120   b  and the bottom U-tube  308   c  of the bottom radiant heater  120   c  are connected to the first blower unit  304  and the second blower unit  306  respectively via a first coupler  316  rotatably connected to a second coupler  314 . 
     The second set of radiant heaters  120   d-f , shown as panel B on FIG. 2, are similarly attached to a first blower unit  404  and a second blower unit  406  via a first coupler  416   a-c  rotatably connected to a second coupler  414   a-c.    
     Also in the preferred embodiment, a back panel  124   a,b  is positioned on each side wall  106 ,  110  of the oven  100  behind the radiant heaters  120   a-f . The back panels  124   a,b  are preferably made of stainless steel, and optionally may be painted flat black. The back panels  124   a,b  are used to capture any radiant energy emitted from the radiant heaters  120   a-f  that miss the object  202 . The ambient temperature of the oven  100  is maintained via these back panels  124   a,b  with the exhaust fan  132  and the radiant heaters  120   a-f.    
     Also in the preferred embodiment, the radiant heaters  120   a-f  discharge their exhaust air through the exhaust fan  132  and out of the oven chamber  102 . However, alternatively, the exhaust fan  132  redirects partial exhaust air back into the oven chamber  102 , during which negative pressure must be maintained within the oven chamber  102  to ensure proper flow of the exhaust air through the exhaust fan  132  and the distribution of heat throughout the oven chamber  102 . This internal routing of partial exhaust air raises the ambient temperature within the oven  100  faster than in conventional curing ovens, resulting in the oven  100  reaching ambient temperatures of 300-500° F. much faster. Furthermore, in the alternative embodiment, the re-entry of the partial exhaust air is preferably through a vent in the bottom  108  of the oven chamber  102  as a means for reducing the amount of dust and/or foreign particles introduced into the oven chamber  102  and as a means for taking advantage of rising hot air in curing/heating the object  202 . 
     In an alternative embodiment, a conventional turbulent fan  602  is mounted to the top wall  104  of the oven  600 . The turbulent fan  602  is mounted on the top wall  104  for convenience purpose only. It would be readily apparent to mount the turbulent fan  602  on a different wall of the oven  600 . The turbulent fan  602  is used in combination with a means for deflecting the air flow, including an air direction unit  604 , to circulate air within the oven chamber  102  of the oven  600 , thereby employing convection heat. 
     An air direction unit  604  is used to divide the circulated air into a first air flow  620  directed to the first side wall  106  of the oven  600  and a second air flow  618  directed to the second side wall  110  of the oven  600 . A first deflectors  612  is positioned in proximity to the first side wall  106  to direct the first air flow  620  from the top of the oven chamber  102 , down the side wall  106  to the bottom wall  108 , then up from the bottom wall  108  toward the object  202  being cured/heated. The first deflector  612  has a first curved portion  614  at one end and a second curved portion  616  at its other end to aid in the deflection of the first air flow  620 . Similarly, a second deflector  606  is positioned in proximity to the second side wall  110  to direct the second air flow  618  from the top of the oven chamber  102 , down the sidewall  110  to the bottom wall  108 , then up from the bottom wall  108  toward the object  202  being cured/heated. The second deflector  606  has a first curved portion  608  at one end and a second curved portion  610  at its other end to aid in the deflection of the second air flow  618 . Therefore, the first deflector  612  and the second deflector  606  aim the heated air directly at the object  202  being cured/heated. The turbulent fan  602  is controlled by a variable frequency driver and the computer system  700  for full flow control of airflow within the oven chamber  102 . 
     In the preferred embodiment, one or more types of sensors are placed throughout the oven chamber  102  to assist in regulating the radiant heaters  120   a-f . For example, a water-cooled object temperature sensor (“object sensor”)  126  is positioned within the oven chamber  102  and is directed at the object  202  being cured/heated. In the present invention, the object sensor  126  is pivotally connected on top of a support frame  128  that is vertically adjustable. Therefore, the object sensor  126  can be adjusted to read the temperature of the object  202  at an appropriate spot on the object  202 . In another embodiment, the object sensor  126  may be suspended from the top  104  of the oven chamber  102  to monitor the temperature of the object  202  being cured/heated. 
     The objected sensor  126  is described in terms of a water cooled sensor for convenience purpose only. It would be readily apparent for one of ordinary skill to use a comparable object sensor  126  for determining the temperature of the object  202  as it is being cured/heated. Furthermore, water cooled sensors are well known in the relevant arts and are commercially available. Although the figures only show the use of a single object sensor  126 , this too is for convenience only. It would be readily apparent to one of ordinary skill in the relevant art to incorporate a plurality of object sensors  126  to monitor the object&#39;s  202  temperature. The temperature readings from all object sensors  126  are input directly into the computer system  700  described below and are used to regulate the radiant heaters  120   a-f  of the oven  100 . In addition, the computer system  700  monitors and regulates the water flow to the object sensor  126  to ensure the gradual heating of the water, thereby preventing any fogging of the lens of the object sensor  126 . The computer system  700  regulates the water pressure to the object sensor  126  using a variable frequency driver according to well known methods. 
     In addition, the oven  100  may incorporate zero or more ambient temperature sensors  130  positioned throughout the oven chamber  102 . Sensors for monitoring ambient temperature are well known in the relevant art and it would be readily apparent for one of ordinary skill to incorporate one or more such ambient temperature sensors  130  in the oven  100  of the present invention. The temperature readings from all ambient temperature sensors  130  are input directly into the computer system  700  described below and are used to regulate the radiant heaters  120   a-f  of the oven  100 . 
     In the preferred embodiment, the radiant heaters  120   a-f , the turbulent fan  602 , the exhaust fan  132  and the ambient temperature of the oven  100  are electronically controlled via a computer system  700  which is described in more detail below. The computer system  700  is connected to the oven  100 , the radiant heaters  120   a-g , the turbulent fan  602 , and exhaust fan  132  via a control box  134  using conventional means. Alternatively, the radiant heaters  120   a-f , the turbulent fan  602 , exhaust fan  132  and ambient temperature can be controlled manually. 
     In operation, an object  202  is placed centrally within the oven chamber  102  of the oven  100 . An operator manually or electronically pivots and rotates the radiant heaters  120   a-f  to ensure that the emitted heat is directed to the appropriate portion(s) of the object  202  to ensure a uniform curing of the object  202 . The operator also positions the object sensor  126  to point at the center, or other spot, of the object  202 . Based on the composition of the object  202 , the operator then programs the radiant heaters  120   a-f  via the control box  134  to specific temperatures and time durations to customize the cure process for the object  202 . If the turbulent fan  602  is to be used, then once the gel process of the powder paint on the object  202  occurs, e.g., after a five (5) minute delay, the computer system  700  turns on the turbulent fan  602 , forcing the heated air to the bottom  108  of the oven chamber  102  where the deflectors  124   a,b  force the air flow toward the center of the oven chamber  102 , resulting in a uniform flow of convection heat transfer to the object  202  being cured. 
     B. Control of Heating Methods 
     FIG. 7 is a block diagram showing an exemplary computer system  700  which can be used with a curing oven  100  of the present invention. The computer system  700  includes one or more processors, such as a processor  704 . The processor  704  is connected to a communication infrastructure  702 , e.g., a communications bus, cross-over bar, or network. Various software embodiments are described in terms of this exemplary computer system  700 . After reading this description, it will become apparent to a person of ordinary skill in the relevant art(s) how to implement the invention using other computer systems and/or computer architectures. 
     The computer system  700  includes a display interface  708  that forwards graphics, text, and other data from the communications infrastructure  702  (or from a frame buffer not shown) for display on the display unit  710 , e.g., a computer screen or monitor on which a graphical user interface, including a window environment, may be displayed. The display interface  708  can also include one or more input peripherals, including, for example, a keyboard, a mouse, a light pen, a pressure-sensitive screen, etc., which provide a user with the capability of entering such input to the computer system  700 . 
     The computer system  700  also includes a main memory  706 , preferably random access memory (RAM), and may also include a secondary memory  712 . The secondary memory  712  may o include, for example, a hard disk drive  714  and/or a removable storage drive  716 , representing a floppy disk drive, a magnetic tape drive, an optical disk, a compact disk drive, etc. which is read by and written to by a removable storage unit  718 . The removable storage unit  718 , also called a program storage device or a computer program product, represents a floppy disk, magnetic tape, optical disk, compact disk, etc. As will be appreciated, the removable storage unit  718  includes a computer usable storage medium having stored therein computer software and/or data. The removable storage drive  716  reads from and/or writes to a removable storage unit  718  in a well known manner. 
     In alternative embodiments, secondary memory  712  may also include other similar means for allowing computer programs or other instructions to be loaded into the computer system  700 . Such means may include, for example, an interface  720  and a removable storage unit  722 . Examples of an interface  720  may include a program cartridge and cartridge interface (such as that found in video game devices), a removable memory chip (such as EPROM, or PROM) and associated socket, and other removable storage units  722  and interfaces  720  which allow software and data to be transferred from the removable storage unit  722  to the computer system  700 . 
     In this document, the term “computer program medium” and “computer usable medium” are used to generally refer to media such as removable storage unit  718 ,  722 , a hard disk installed in hard disk drive  714 . These “computer program products” are means for providing software to a computer system  700 . Portions of the present invention are directed to such computer program products. It would be readily apparent for one of ordinary skill in the relevant art to design and implement the described software for controlling the radiant heaters  120   a-f  and turbulent fan  602  of the curing oven  100 . 
     Computer programs (also called computer control logic) are stored in main memory  706  and/or secondary memory  712 . Such computer programs, when executed, enable the computer system  700  to perform the features of the present invention as discussed herein. In particular, the computer programs, when executed, enable the processor  704  to perform the features of the present invention. Accordingly, such computer programs represent controllers of the computer system  700 . 
     In an embodiment where portions of the invention are implemented using software, the software may be stored in a computer program product and loaded into computer system  700  using removable storage drive  716  or a hard disk drive  714 . The software, when executed by the processor  704 , causes the processor  704  to perform the functions of the invention as described herein. 
     In another embodiment, the invention is implemented primarily in hardware using, for example, a hardware state machine, such as application specific integrated circuits (ASICS). Implementation of the hardware state machine so as to perform the functions described herein will be apparent to persons skilled in the relevant arts. 
     In yet another embodiment, the invention is implemented using a combination of hardware and software. 
     The preferred computer system  700  is a SLC500 which is commercially available. The SLC500 is used for convenience purpose only, the present invention also can be developed on any appropriate computer system, e.g., a personal computer, sun workstation or mainframe computer. The present invention is described in terms of a computer system  700  having a single processor  704  for convenience purposes only. It would be readily apparent, however, to one skilled in the relevant arts to use a computer system  700  having multiple processors  704 , thereby executing the present invention in parallel. The preferred embodiment of the present invention is implemented in software, and more specifically, is written in the programming language RSLogix 500, version 2.5, available from Rockwell Software. The preferred embodiment is described in these terms for convenience purpose only. Other comparable computer systems  700  and programming languages could alternatively be used. 
     FIG. 8 is a data flow diagram showing the operational flow of the process of curing an object  202  using an oven  100  of the present invention. The curing oven controller  802  is a software program executing within the computer system  700  of the control box  134 . The curing oven controller  802  receives input from temperature sensors  804 , user input  806 , and a water gauge sensor  824 . The temperature sensors  804  comprise one or more object sensors  126  as well as zero or more ambient temperature sensors  130 , wherein both types of sensors send sensor temperatures  808  to the curing oven controller  802 . The user input  806  comprises various curing parameters  810  used to control and maintain the curing process within the curing oven  100 . The curing parameters  810  include, but are not limited to, a preset time for setting the cure time of the object  202 , a preset temp for setting the cure temperature of the object  202 , a maximum ambient temperature for the oven chamber  102 , a maximum temperature for the top radiant heaters  120   a,d , a maximum temperature for the middle radiant heaters  120   b,e , and a maximum temperature for the bottom radiant heaters  120   c,f . The water gauge sensor  824  provides a negative static pressure  822  to the curing oven controller  802  for use in controlling the exhaust fan  132 . 
     Once the curing oven controller  802  receives these curing parameters  810 , the curing oven controller  802  controls the radiant heaters  120   a-f  via radiant heater (RH) controls  814 , the exhaust fan  132  via exhaust fan controls  820 , the water pump  828  via water pump controls  826 , and optionally controls the turbulent fan  602  via turbulent fan controls  812 . The curing oven controller  802  sends display status  818  data to the display unit  710  as a means for informing the operator of the status of the curing process. 
     FIG. 9 provides an operational control flow for the processing of the curing oven controller  802 . Processing begins at step  902  and immediately continues to step  904 . In step  904 , the curing oven controller  802  loads the curing parameters  810 . Continuing to step  906 , the curing oven controller  802  scales the curing parameters  810  according to standard scaling principals. Once the scaling is complete, the curing oven controller  802  continues to step  908  in which the curing oven controller  802  controls the curing oven  100 . The operation of step  908  is described in greater detail below. After completing the curing of the object  202 , the curing oven controller  802  proceeds to step  910  wherein it turns off the curing oven  100 , including the radiant heaters  120   a-f , the exhaust fan  132 , and the turbulent fan  602  if used. All processing is complete, thereby the curing oven controller  802  continues to step  912  in which it turns on a finished lamp signal on the control box  132  and an audible alarm, signaling the completion of the curing process within the oven  100 . Processing is terminated at step  914 . 
     Referring again to step  908 , the processing of the control of the curing oven  100  is shown on FIG.  10 . Processing begins at step  1002  and immediately proceeds to step  1004 . In step  1004 , the curing oven controller  802  determines whether the curing timer (a timer used to calculate the actual cure time of the object  202 ) has reached the preset time entered by the operator. If the curing timer does not equal the preset time, processing proceeds to step  1008 . 
     In step  1008 , the curing oven controller  802  determines whether the curing timer has even been activated or started. If the curing timer has not been started, processing proceeds to step  1010  wherein the curing oven controller  802  determines whether the object temperature via the objected sensor  126  is equal to the preset temp entered by the operator. If the object temperature equals the preset temp, then the curing stage has begun and the curing timer must be started. Processing proceeds to step  1012  wherein the curing timer is started. Processing continues to step  1016  described in greater detail below. 
     Referring against to step  1010 , if the object temperature does not equal the preset temp, then the curing stage has not begun and processing proceeds directly to step  1016  described in greater detail below. 
     Referring back to step  1008 , if the curing oven controller  802  determines that the curing timer has already started then the object  202  is in the curing stage and curing oven controller  802  proceeds to step  1014 . 
     In step  1014 , the curing oven controller  802  checks the turbulent fan  602  and controls when it is turned on and off. Step  1014  is described in greater detail below. After checking the turbulent fan  602 , processing continues to step  1016 . In step  1016 , the curing oven controller  802  checks the ambient temperature within the oven chamber  102 . Step  1016  is described in greater detail below. Once the ambient temperature is regulated, the curing oven controller  802  continues to step  1018  to check the radiant heaters  120   a-f  and regulate their activity. Step  1018  is also described in greater detail below. 
     Once the temperature of the object  202  has been controlled and regulated, the curing oven controller  802  returns to step  1004  to determine whether the curing stage of the object  202  is complete. If the curing timer equals the preset time, the curing oven controller  802  proceeds to step  1006  wherein processing is returned to step  908  and continues immediately to step  910 . 
     FIG. 11 is the operational flow of step  1016  wherein the curing oven controller  802  checks and regulates the ambient temperature within the oven chamber  102 . Processing begins at step  1102  and immediately continues to step  1104 . In step  1104 , the curing oven controller  802  determines whether the ambient temperature in the oven chamber  102 , as received via an ambient temperature sensor  130 , is less than a maximum ambient temperature. In the preferred embodiment, the maximum ambient temperature is input to the computer system  700  via the curing parameters  810 . If the ambient temperature is greater than or equal to the maximum, processing continues to step  1110 . 
     In step  1110 , the curing oven controller  802  initiates an alarm, visual and/or audible, because the ambient temperature within the oven chamber  102  is too hot. Continuing to step  1114 , which is described in greater detail below, the curing oven controller  802  turns off the radiant heaters  120   a-f  before moving to step  1118 . The curing oven controller  802  also can electronically pivot the radiant heaters  120   a-f  such that any residual radiant heat emitted from the radiant heaters  120   a-f  are now directed away from the object  202 . 
     In step  1118 , the curing oven controller  802  increases the speed of the exhaust fan  132  as a means for quickly removing heat from within the oven chamber  132 . Processing continues to step  1120  wherein the curing oven controller  802  returns processing to step  1016  and it continues immediately to step  1018 . 
     Referring again to step  1104 , if the ambient temperature is less than the maximum ambient temperature, processing proceeds to step  1106 . In step  1106 , the curing oven controller  802  determines whether there is a negative static pressure  822  within the oven chamber  102 . If there is, processing proceeds to step  1108 . In step  1108 , the curing oven controller  802  decreases the speed of the exhaust fan  132  to maintain a stable heat environment within the oven chamber  102 . Processing continues to step  1116  wherein the curing oven controller  802  clears the ambient timer before proceeding to step  1120 . In step  1120 , the curing oven controller  802  returns processing to step  1016  wherein it continues immediately to step  1018 . 
     Referring again to step  1106 , if the curing oven controller  802  determines that there is not a negative static pressure  822  within the oven chamber  102 , processing proceeds to step  1112 . In step  1112 , the curing oven controller  802  increases the speed of the exhaust fan  132  to lower the temperature within the oven chamber  102 . Processing continues to step  1116  wherein the curing oven controller  802  clears the ambient timer before proceeding to step  1120 . In step  1120 , the curing oven controller  802  returns processing to step  1016  wherein it continues immediately to step  1018 . 
     FIG. 12 is an operational diagram showing the processing of step  1114 . In step  1114 , processing begins at step  1202  and proceeds immediately to step  1204 . In step  1204 , the curing oven controller  802  determines whether the ambient timer has been started. If the ambient timer has not been started then processing continues to step  1206 . In step  1206 , the ambient temperature in the oven chamber  102  is too hot, therefore, the curing oven controller  802  starts the ambient timer to calculate the duration of time that the ambient temperature is too high. Once the timer is started, processing proceeds to step  1220  wherein processing returns to step  1114 . 
     Referring again to step  1204 , if the ambient timer has not been started, the curing oven controller  802  continues to step  1208 . In step  1208 , the curing oven controller  802  determines weather the ambient timer has been active for 1 minute. If the time has been so active, the curing oven controller  802  continues to step  1210  wherein it turns off the top radiant heaters  120   a,d . The curing oven controller  802  may also pivot the top radiant heaters  120   a,d  away from the object  202  such that any residual radiant heat emitted from the top radiant heaters  120   a,d  is directed away from the object  202 , thereby lowering the object  202  temperature. Once the top radiant heaters  120   a,d  have been turned off, processing proceeds to step  1220  and returns to step  1114 . 
     Referring again to step  1208 , if the ambient timer has not been active for 1 minute, the curing oven controller  802  continues to step  1212 . In step  1212 , the curing oven controller  802  determines weather the ambient timer has been active for 2 minutes. If the timer has been so active, the curing oven controller  802  continues to step  1214  wherein it turns off the middle radiant heaters  120   b,e . The curing oven controller  802  may also pivot the middle radiant heaters  120   b,e  away from the object  202  such that any residual radiant heat emitted from the middle radiant heaters  120   b,e  is directed away from the object  202 , thereby lowering the object  202  temperature. Once the middle radiant heaters  120   b,e  have been turned off, processing proceeds to step  1220  and returns to step  1114 . 
     Referring again to step  1212 , if the ambient timer has not been active for 2 minutes, the curing oven controller  802  continues to step  1216 . In step  1216 , the curing oven controller  802  determines weather the ambient timer has been active for 3 minutes or more. If the timer has been so active, the curing oven controller  802  continues to step  1218  wherein it turns off the bottom radiant heaters  120   c,f . The curing oven controller  802  may also pivot the bottom radiant heaters  120   c,f  away from the object  202  such that any residual radiant heat emitted from the bottom radiant heaters  120   c,f  is directed away from the object  202 , thereby lowering the object  202  temperature. Once the bottom radiant heaters  120   c,f  have been turned off, processing proceeds to step  1220  and returns to step  1114 . 
     Referring again to step  1216 , if the ambient timer has not been active for 3 minutes or more, the curing oven controller  802  continues to step  1220  because it has already turned off all of the radiant heaters  120   a-f  and returns to step  1114 . 
     FIG. 13 shows the operational flow of step  1016  for checking the radiant heaters  120   a-f . Processing begins at step  1302  and proceeds immediately to step  1304 . In step  1304 , the curing oven controller  802  determines whether the object temperature is less than the top radiant heater maximum temperature and whether the top radiant heaters  120   a,d  are turned off. If so, the curing oven controller  802  proceeds to step  1306  wherein it turns the top radiant heaters  120   a,d  on. Processing continues to step  1316  wherein processing returns to step  1016 . 
     Referring again to step  1304 , if the curing oven controller  802  determines that the object temperature is not less than the top radiant heater maximum temperature or the top radiant heaters  120   a,d  are already turned off, the curing oven controller  802  proceeds to step  1308 . In step  1308 , the curing oven controller  802  determines whether the object temperature is less than the middle radiant heater maximum temperature and whether the middle radiant heaters  120   b,e  are turned off. If so, the curing oven controller  802  proceeds to step  1310  wherein it turns the middle radiant heaters  120   b,e  on. Processing continues to step  1316  wherein processing returns to step  1016 . 
     Referring again to step  1308 , if the curing oven controller  802  determines that the object temperature is not less than the middle radiant heater maximum temperature or the middle radiant heaters  120   b,e  are already turned off, the curing oven controller  802  proceeds to step  1312 . In step  1312 , the curing oven controller  802  determines whether the object temperature is less than the bottom radiant heater maximum temperature and whether the bottom radiant heaters  120   c,f  are turned off. If so, the curing oven controller  802  proceeds to step  1314  wherein it turns the bottom radiant heaters  120   c,f  on. Processing continues to step  1316  wherein processing returns to step  1016 . 
     Referring again to step  1312 , if the curing oven controller  802  determines that the object temperature is not less than the bottom radiant heater maximum temperature or the bottom radiant heaters  120   c,f  are already turned off, the curing oven controller  802  proceeds to step  1316  wherein processing returns to step  1016 . 
     FIG. 14 is an operational diagram showing the processing of step  1014  wherein the curing oven controller  802  checks the turbulent fan  602 . Processing begins at step  1402  and immediately proceeds to step  1404 . In step  1404 , the curing oven controller  802  determines whether the turbulent fan  602  is on. If the turbulent fan  602  is on, processing proceeds to step  1410  wherein control is returned to step  1014  and immediate continues to step  1016 . 
     Referring again to step  1404 , if the curing oven controller  802  determines that turbulent fan  602  is off, processing proceeds to step  1406 . In step  1406 , the curing oven controller  802  determines whether a time delay, e.g., five minutes which is enough time for the gel process of powder based paint curing to occur, has elapsed. If the delay has occurred, processing proceeds to step  1408  wherein the curing oven controller  802  turns on the turbulent fan  602 . Continuing to step  1410 , processing returns to step  1014  wherein it immediately continues to step  1016 . 
     Referring again to step  1406 , if the curing oven controller  802  determines that the time delay has not occurred, processing proceeds to step  1410 , wherein it returns to step  1014  and immediately continues to step  1016 . 
     FIGS. 15-20 illustrate the preferred embodiment of user screens used in connection with the curing oven controller  802  as displayed on the controller box  130 . FIG. 15 shows the main screen  1502  of the user interface for the Curing Oven Controller  802 . FIG. 16 shows the display screen of the user interface for the Oven Start/Stop/Monitor process  1602 . FIG. 17 shows the display screen of the user interface for the Oven Exhaust Fan process  1702 . FIG. 18 shows the display screen of the user interface for the Oven Heater Control process  1802 . FIG. 19 shows the display screen of the user interface for the Infrared Water Pump Sensor process  1902 . FIG. 20 shows the display screen of the user interface for the Oven Process Parameters  2002 . 
     II Test Results 
     Test results using the curing oven  100  of the present invention are shown in FIGS. 21-24. The tests show the cure time for an object  202  comprised of 14 gauge steel using a curing oven  100  of the present invention. 
     A. Test 1 
     The following curing parameters  810  were used for Test 1: 
     
       
         
               
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 preheat data 
                 = 
                 400° F. for 16 minutes 
               
               
                   
                 preset time 
                 = 
                 30 minutes 
               
               
                   
                 preset temp 
                 = 
                 400° F. 
               
               
                   
                 max ambient 
                 = 
                 450° F. 
               
               
                   
                 top heater max 
                 = 
                 375° F. 
               
               
                   
                 middle heater max 
                 = 
                 400° F. 
               
               
                   
                 bottom heater max 
                 = 
                 425° F. 
               
               
                   
                   
               
             
          
         
       
     
     The elements on FIG. 21 are: 
     Element  2102 =top air temperature—first top sensor (peak temp=473) 
     Element  2104 =side one of oven chamber (peak temp=466) 
     Element  2106 =side two of oven chamber (peak temp=473) 
     Element  2108 =top air temperature—second top sensor (peak temp=428) 
     B. Test 2 
     The following curing parameters  810  were used for Test 2: 
     
       
         
               
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 preheat data 
                 = 
                 400° F. for 16 minutes 
               
               
                   
                 preset time 
                 = 
                 30 minutes 
               
               
                   
                 preset temp 
                 = 
                 400° F. 
               
               
                   
                 max ambient 
                 = 
                 450° F. 
               
               
                   
                 top heater max 
                 = 
                 375° F. 
               
               
                   
                 middle heater max 
                 = 
                 400° F. 
               
               
                   
                 bottom heater max 
                 = 
                 425° F. 
               
               
                   
                   
               
             
          
         
       
     
     The elements on FIG. 22 are: 
     Element  2202 =bottom air temperature—first bottom sensor (peak temp=423) 
     Element  2204 =side one of oven chamber (peak temp=464) 
     Element  2206 =side two of oven chamber (peak temp=478) 
     Element  2208 =bottom air temperature—second bottom sensor (peak temp=403) 
     C. Test 3 
     The following curing parameters  810  were used for Test 3: 
     
       
         
               
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 preheat data 
                 = 
                 350° F. for 16 minutes 
               
               
                   
                 preset time 
                 = 
                 30 minutes 
               
               
                   
                 preset temp 
                 = 
                 350° F. 
               
               
                   
                 max ambient 
                 = 
                 400° F. 
               
               
                   
                 top heater max 
                 = 
                 375° F. 
               
               
                   
                 middle heater max 
                 = 
                 400° F. 
               
               
                   
                 bottom heater max 
                 = 
                 425° F. 
               
               
                   
                   
               
             
          
         
       
     
     The elements on FIG. 23 are: 
     Element  2302 =top air temperature—first top sensor (peak temp=423) 
     Element  2304 =side one of oven chamber (peak temp=415) 
     Element  2306 =side two of oven chamber (peak temp=406) 
     Element  2308 =top air temperature—second top sensor (peak temp=379) 
     D. Test 4 
     The following curing parameters  810  were used for Test 4: 
     
       
         
               
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 preheat data 
                 = 
                 350° F. for 16 minutes 
               
               
                   
                 preset time 
                 = 
                 30 minutes 
               
               
                   
                 preset temp 
                 = 
                 350° F. 
               
               
                   
                 max ambient 
                 = 
                 400° F. 
               
               
                   
                 top heater max 
                 = 
                 375° F. 
               
               
                   
                 middle heater max 
                 = 
                 400° F. 
               
               
                   
                 bottom heater max 
                 = 
                 425° F. 
               
               
                   
                   
               
             
          
         
       
     
     The elements on FIG. 24 are: 
     Element  2402 =bottom air temperature—first bottom sensor (peak temp=379) 
     Element  2404 =side one of oven chamber (peak temp=403) 
     Element  2406 =side two of oven chamber (peak temp=397) 
     Element  2408 =bottom air temperature—second bottom sensor (peak temp=374) 
     Conclusion 
     While various embodiments of the present invention have been described above, it should be understood that they have been presented by the way of example only, and not limitation. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the specification and the appended claims. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined in accordance with the specification and any equivalents.