Abstract:
An oven is provided for re-baking welding consumables in an efficient and improved heat distribution manner. The oven includes a first chamber having a plurality of first chamber vents positioned on at least one sidewall of the first chamber and a heating source in a second chamber, the second chamber being in fluid communication with the first chamber, and one or more third chambers situated on a sidewall of the first chamber, wherein heat energy from the heating source flows through the third chamber into the first chamber, and wherein the heat energy from the heating source is substantially and evenly distributed inside the first chamber.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. provisional patent application No. 61/242,174 entitled “Oven” and filed on Sep. 14, 2009, which is hereby incorporated by reference herein. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to industrial ovens. More particularly, the present invention relates generally to welding consumable re-baking ovens. 
       BACKGROUND OF THE INVENTION 
       [0003]    Welding consumables, such as electrodes and flux, are integral components when joining steel and alloy steels. With the increased need for higher strength steel and steel alloy, there is a need for specialized welding consumables. Welding electrodes that have been exposed to the atmosphere for extended periods of time negatively affect weld quality, therefore there is a need to recondition or re-bake welding consumables to remove excess moisture from the electrodes. Excess moisture in electrodes increases the propensity for hydrogen in the weld, which can often cause cracking and premature failure of a weld. Due to the increased need for specialized welding consumables, it is critical to properly re-bake electrodes. 
         [0004]    Re-baking ovens use significantly large amounts of energy to maintain high temperatures adequate for proper re-baking. These ovens typically require a duty-cycle in the 30% to 50% range. Further, these ovens are subject to re-baked product quality consistency issues as a result of non-uniform temperatures inside the oven and insufficient positioning of the products during the re-baking process. 
         [0005]    It would be advantageous to have a re-baking oven that is efficient and reduces the amount of operating energy. It would be a further advantage to have a re-baking oven that distributes heat energy evenly throughout a heating chamber to improve quality consistency among the products re-baked in the oven. 
       SUMMARY OF THE INVENTION 
       [0006]    In accordance with at least one embodiment, an oven is provided with a heating element within a heating element chamber having a plurality of chamber vents. The oven also includes a heating chamber for re-baking welding consumables, and a plurality of vent chambers in fluid communication with the heating element chamber and heating chamber. 
         [0007]    In accordance with another embodiment, a welding consumable re-baking oven is provided with a first chamber having a plurality of first chamber vents positioned on at least one sidewall of the first chamber, a heating source in a second chamber, the second chamber being in fluid communication with the first chamber. The oven further includes one or more third chambers situated on a sidewall of the first chamber, wherein heat energy from the heating source flows through the third chamber into the first chamber, and wherein the heat energy from the heating source is substantially and evenly distributed inside the first chamber. 
         [0008]    In accordance with yet another embodiment, a method for re-baking a welding consumable is provided, the method including placing a welding consumable within a first chamber, activating a control unit configured for maintaining a temperature range in the oven by cycling a heat source, and radiating heat energy from the heat source situated in a second chamber. The method further includes directing the radiated heat energy through a plurality of first passages in the sidewall of the second chamber, communicating the radiated heat energy upwards from the first passages into second passages situated in the sidewall of the first chamber, and substantially uniformly distributing the heat energy from the second chamber and second passages into the first chamber. The method in another embodiment further including cycling the heat source with about a ten-percent duty-cycle. 
         [0009]    Other embodiments, aspects, features, objectives and advantages of the present invention will be understood and appreciated upon a full reading of the detailed description and the claims that follow. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    Embodiments are disclosed with reference to the accompanying drawings and are for illustrative purposes only. The embodiments are not limited in their application to the details of construction or the arrangement of the components illustrated in the drawings. Rather, the embodiments are capable of being varied or of being practiced or carried out in other various ways. The drawings illustrate a best mode presently contemplated for carrying out one embodiment. In the drawings: 
           [0011]      FIG. 1  is a perspective view of an exemplary oven; 
           [0012]      FIG. 2  is a front view of the oven of  FIG. 1  in accordance with at least one embodiment; 
           [0013]      FIG. 3  is a front view of the oven in  FIG. 2 , with the oven door open; 
           [0014]      FIG. 4  is a cross-sectional side view along lines  4 - 4  of the oven in  FIG. 2 ; 
           [0015]      FIG. 5  is a cross-sectional front view along lines  5 - 5  of the oven in  FIG. 4 ; 
           [0016]      FIG. 6  is a perspective view of a heating rack for the oven in  FIG. 1 , in accordance with at least one embodiment; and 
           [0017]      FIGS. 7A and 7B  are side cross-sectional views of alternative heating chamber vent configurations in accordance with at least one embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0018]    An exemplary re-baking oven  2  is provided in  FIGS. 1-2 . The oven  2  is generally a cuboidal structure, such as a rectangle, although in some embodiments the oven  2  can include other shapes. The oven  2  includes a top  4 , a bottom  6 , a left side  8 , a right side  10 , and a front  11 . The front  11  includes a door  12 , a control unit  14 , and a power switch  16 . The top includes a set of hoisting eyelets  18  and the bottom includes a set of wheels  20 . The door  12  is operably connected to the oven  2  through a set of two hinges  22  secured to the front  11  and a mechanical handle latch  24 . In one embodiment the oven includes a set of four eyelets  18  and a set of four wheels  20 , although in other embodiments the eyelets and/or the wheels can be omitted. 
         [0019]    The control unit  14  is a typical oven controller, such as the exemplary unit identified below that provides user operational control of the oven  2  such as, allowing a user to turn the oven on or off and to vary the target temperature within the oven. In addition, temperature information and heating element status are provided by the control unit  14 . An exemplary control unit  14  includes a Love model 16B PID controller as manufactured by Dwyer Industries Inc. (Michigan City, Ind.). The power switch  16  serves as a master On/Off switch. An exemplary power switch  16  is a Part # A22SC2M02 Double Pole On/off Power switch as manufactured by OMRON Corporation (Kyoto, Japan). 
         [0020]    Referring to  FIG. 3 , a front view of the oven  2  is provided with the door  12  in an open position exposing the oven interior  27 . The oven interior  27  includes a heating chamber  26  for heating a product and an element chamber  36  for providing heat energy for use by the heating chamber  26 . The heat energy can be provided by one of numerous types of sources, such as one or more electric heating elements  38  ( FIG. 4 ). Oven  2  includes an insulating material  28  situated on at least one of a doorframe  30  or on the door  12  that serves to maintain the heat energy inside the heating chamber  26  about the door opening. A removable rack  32  can be provided within the heating chamber  26  for stacking products, such as welding consumables, during the re-baking process. In at least one embodiment, the rack  32  is configured to extend substantially to the extents of the heating chamber  26  to optimize the space. In another embodiment the rack  32  is omitted. The rack  32  can rest on a bottom portion  34  of the heating chamber  26  or be supported at another location in the heating chamber, such as the sidewalls  41 ,  43 . The bottom portion  34  functions as the top of the element chamber  36 . The heat energy provided by the elements  38  increases the temperature of the medium, such as air, gas or liquid, within the element chamber  36 . The heat energy (e.g., heated gas) is in fluid communication with the heating chamber  26  and travels from the element chamber  36 , through vent chambers  46 ,  48  and into the heating chamber  26 , as discussed below. 
         [0021]    Referring to  FIG. 4 , a cross sectional view of the oven  2  along lines  4 - 4  is provided. The heating elements  38  are shown positioned within the element chamber  36 . In at least one embodiment, heating elements  38  include 3 resistive 1500 Watts heating elements in a 3-phase delta configuration (see  FIG. 5 ) for a total of 4500 Watts. An oven with this heating element configuration has a temperature range from ambient temperature to about 800 degrees Fahrenheit. In another embodiment, a single resistive heating element can be provided that generates greater than 1500 Watts. In another embodiment, one or more suitable heating elements, as known in the art, can be provided to generate an oven temperature range that exceeds 800 degrees Fahrenheit. 
         [0022]    Referring now to  FIGS. 4-5 , in at least one embodiment, the element chamber  36  and the heating chamber  26  include sidewalls  41 ,  43  on left and right sides, respectively, the sidewalls include sidewall lower portions  42 ,  44 , situated in the element chamber  36 , and sidewall upper portions  52 ,  54 , situated in the heating chamber  26 . At least one of the sidewall lower portions  42 ,  44  includes a plurality of element vents  40  which form passages through the sidewall lower portions  42 ,  44 . The element vents  40  serve to provide communication between the element chamber  36  and one or more vent chambers  46 ,  48  that extend substantially vertically along the sidewalls  41 ,  43 . The plurality of heating chamber vents  50  are positioned along one or more sidewall upper portions  52 ,  54 . The heating chamber vents  50  form a plurality of passages that provide communication between the heating chamber  26  and the vent chambers  46 ,  48 . In operation, heat energy is generated in the element chamber  36  and is passed through the element vents  40  into the vent chambers  46 ,  48  where it travels upwards and through the heating chamber vents  50  into the heating chamber  26 . 
         [0023]    To provide uniform heating in the heating chamber  26 , both natural and guided convection currents are utilized, at least in part, by configuring ends  31 ,  33 , of the bottom portion  34  to raise upward slightly as they extend a distance from a center point  35  and towards the sidewalls  41 ,  43  to form sloped surfaces  47 ,  49  as seen in  FIG. 5 . Since the bottom portion  34  also acts as the ceiling for the element chamber  36 , the sloped surfaces  47 ,  49  help guide the heated air from the element chamber  36  in the direction of the element vents  40 . In one embodiment, the sloped surfaces  47 ,  49  can be modified by increasing or decreasing the slope angle from what is provided in  FIG. 5 . In another embodiment, the bottom portion  34  can begin sloping up towards the sidewall lower portions  42 ,  44  from the center point  35 . 
         [0024]    After passing through the element vents  40 , the rising heat energy naturally rises in the vent chambers  46 ,  48 . The heated energy is then guided into the heating chamber  26  by the positioning of the heating chamber vents  50 . Since the heating element  38  is close to the bottom portion  34 , this portion of the heating chamber  26  will be naturally heated. However, as the distance from the heating element  38  increases inside the heating chamber  26 , the more guidance the heating energy requires to provide a substantially uniform temperature inside the oven  2 . To accomplish such guidance, an increasing proportional number of heating chamber vents  50  are provided moving from adjacent the bottom portion  34  upwards toward a top  55  of the heating chamber  26 . The increasing proportion of heating chamber vents  50  allow for more heat energy to flow into the heating chamber  26  to compensate for the distance from the heating element. In at least some embodiments, the proportion can decrease prior to increasing. 
         [0025]    In at least one embodiment, the heating chamber vents  50  and element vents  40  are generally circular in shape, having a diameter of about 1 inch. In another embodiment, the heating chamber vents  50  and element vents  40  can range from about 1 centimeter in diameter to about 2 inches or greater in diameter. In other embodiments, the heating chamber vents  50  and element vents  40  can be further varied in size to accommodate various oven requirements. The heating chamber vents  50  and element vents  40  can be identical or different, and can include a variety of one or more shapes, including various sided polygons, and a variety of sizes as desired to accommodate various oven requirements. 
         [0026]    Referring to  FIG. 5 , the oven  2  includes a recess  60  located on the left side  8 . The recess  60  includes various typical oven electrical components for facilitating the operation of the oven, including a transformer  64  and a relay contactor  66 . These and other typical electrical components (not shown) are selectively positioned distal to the heating element  38 . Additionally, insulation (not shown) is located between the heating chamber  26  and the external walls of the oven, thereby inhibiting heat energy from exiting the heating chamber  26 . 
         [0027]    The oven  2  configuration as described above provides an efficient generation of high re-baking temperatures. By example, the duty-cycle of the oven  2  can be lower than the typical value for a conventional oven, for example, in at least one embodiment, the duty-cycle can average about 10%-35%. In another embodiment, the duty-cycle can average about 10%-25%. In still another embodiment, the duty-cycle can average less than 30%. In yet another embodiment, the duty-cycle can average about 10%. The reduced duty-cycle results in a significant energy savings and reduced cost as compared to ovens in the prior art, for example, the oven  2  in one embodiment can consume from about 30% to about 50% less power than typical re-baking ovens. Furthermore, the placement of the heating chamber vents  50  enables substantially uniform heat distribution within the heating chamber  26 , which provides for the uniform re-baking of products, which in turn can provide increased performance of the products. By example, the re-baking of welding consumables with the oven  2  translates into increased weld performance based upon the higher quality electrodes produced by the re-baking process. Comparative testing has shown that when the oven  2  is used for the re-baking of electrodes, the oven  2  provides higher quality electrodes (e.g., more uniform evaporation of moisture) and requires significantly less energy (e.g., reduced duty-cycle) than previously known re-baking ovens. 
         [0028]    An exemplary heating process for re-baking welding consumables using oven  2  includes several steps. The welding consumable is placed on the rack  32  within the heating chamber  26 . The oven  2  is activated by using the power switch  16  to power-on the oven for control, and setting the control unit  14  to select a heating temperature and re-baking time. The temperature and re-baking time are based at least in part upon the material properties of the consumable being re-baked. The control unit  14  activates the heating element  38  generating heat energy within the element chamber  36 . Heat energy in the element chamber  36  radiates outwards and upwards towards the bottom portion  34  (ceiling of the element chamber) and is at least partially directed away from the center point  35  and towards sidewall lower portions  42 ,  44 , and subsequently is pushed through the element vents  40  into the vent chambers  46 ,  48 . Heating energy then proceeds upwards along the vent chambers  46 ,  48  and migrates through the heating chamber vents  50  into the heating chamber  26 . Heating energy that enters the heating chamber  26  surrounds the rack  32  and the consumable situated on the rack  32 . The control unit maintains a desired temperature range and the products are re-baked for a desired amount of time. 
         [0029]    Once the re-baking process is complete, the consumables can be removed. Alternatively, the oven  2  can be used as a holding oven. While functioning as a holding oven, the heating chamber  26  is maintained at a temperature about equal to or less than that used during the re-baking process. Alternatively, welding consumables can be placed in the oven  2  after having been re-baked in a separate oven. In this case, the oven functions only as a holding oven. Welding consumables remain in the oven  2  in order to avoid extended exposure to the atmosphere where they can absorb moisture from the atmosphere. 
         [0030]    Referring now to  FIG. 6 , an exemplary removable rack  32  is shown. The rack  32  includes a plurality of surfaces  58  for positioning products inside the oven  2 . Each of the surfaces  58  include a plurality of heat distribution passages  56  for assisting with the uniform distribution of heat energy inside the oven  2 . Although the rack  32  is shown in  FIG. 6  with the surfaces  58  forming a criss-cross (e.g., diamond) configuration, the shape and orientation of the surfaces  58  can vary to accommodate various products being placed inside the oven  2 . In addition, the heat distribution passages  56  can vary in size and shape, or not be included at all. In one embodiment, the load capacity of the oven  2  with the rack  32  is about 400 lbs. In another embodiment, by varying the size of the oven  2  and the configuration of the rack  32 , the load capacity of the oven  2  can range from about zero to about 1000 lbs or greater. 
         [0031]    Referring to  FIGS. 7A and 7B , alternative heating chamber vent  50  configurations are provided. The configuration in  FIG. 7A  generally has an upside-down triangle shape, which allows for a greater proportion of heating chamber vents  50  situated away from the bottom surface  34 . The configuration in  FIG. 7B  is a randomized pattern with a greater proportion of heating chamber vents  50  situated away from the bottom surface  34 . Both sidewalls  41 ,  43  for the ovens shown in  FIGS. 7A and 7B  can include heating chamber vents  50 . 
         [0032]    It is specifically intended that the aforementioned embodiments and illustrations not be limited as shown and described herein, but rather also include modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come within the scope of the following claims.