Abstract:
A float sled comprising a body with a substantially flat upper surface, a lift plate operationally associated with the body and adapted to move from a first position in proximity to the upper surface of the body to a second position above the first position and above the body, a set of pneumatic air bag lifts associated with the lift plate to raise and lower the lift plate to various horizontal orientations with differing degrees of tilt, and an air bearing adapted to raise the body above the ground.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application derives and claims priority from U.S. provisional application 61/369,341 filed 30 Jul. 2010, which application is incorporated herein by reference. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     This invention relates principally to a metal oven, furnace or kiln (collectively “furnace”), and more particularly to a unique float sled for the movement of heavy components removably attached to such furnace. 
     Some furnaces that supply molten metal for casting and other procedures utilize a regenerative configuration to improve efficiency. The typical regenerative furnace includes an enclosure having a hearth at its bottom for containing a molten metal, which is often aluminum. At one end of the furnace are two ports located above the hearth. These ports are connected to burner assemblies that operate alternately for supplying hot gases to the interior of the furnace enclosure. The temperature of the hot gasses is very high and is sufficient to maintain the metal in the hearth in a molten condition. 
     A typical regenerative burner system comprises at least one pair of regenerative burner assemblies. Each burner assembly has a burner head and a removable media box containing a media that serves as a heat sink. The media usually take the form of ceramic alumina spheres about one-inch in diameter. Typically, the media box is constructed of heavy gage metal and together with the media can weigh upwards of 10,000 pounds. Even a small media box will be very heavy and may weigh hundreds of pounds. 
     Regenerative burners operate as a duel burner unit or as a pair, e.g. burner “A” and burner “B”. While burner “A” is firing, the media in its media box is releasing stored heat to the combustion air that elevates the temperature of the combustion air. The combustion air flows through the media in the media box to the burner head to mix with the gas or oil for combustion. At the same time burner “B” is being utilized as an exhaust system for the combustion hot waste gasses. An exhaust fan draws these hot waste gasses through the burner head of burner “B” and through the media in the burner “B” media box, where the hot waste gasses elevate the temperature of the media and the media bed lining. Once the exhaust gasses downstream of the media box reach a predetermined temperature, which usually takes about 40 to 60 seconds, a pair of air/exhaust duct cycling valves reverse their positions. This switches burner “A” from the burner firing into the industrial furnace to the burner exhausting out of the furnace, and simultaneously switches burner “B” from the burner exhausting to the burner firing. These air/exhaust duct cycling valves are used for switching and reversing the flow of hot gases and combustion air through the media beds. 
     During operation, impurities, additives and coatings that volatilize during the metal heating process in the furnace (e.g., oxidation, etc.) are picked up in the hot waste gas stream and settle out in the media boxes. As the hot waste gasses flow through the media in the media boxes of the two burner assemblies, some of the contaminants also deposit on the media. These deposits eventually clog the media. Hence, from time to time each media box is detached from the burner and taken to a remote location where the media box and the media may be cleaned and otherwise reconditioned. This is a time-consuming and difficult procedure given the size, weight and temperature of the operating media boxes and the operational temperatures of the furnace. Consequently, replacing a media box traditionally requires the use of heavy lifting equipment such as jacks and lifts. Unfortunately, in many operations the media boxes are in positions or locations that are difficult to access. While lift trucks can be used to remove and replace media boxes, the positioning and alignment of the media boxes relative to the furnace ports must be relatively precise. Lift trucks and the like are not well suited to such fine alignments and extreme care must be exercised in using a lift truck or the like, which can easily damage the media box or the furnace. Further, for some furnaces, there may be insufficient room to readily utilize a lift truck. 
     As will become evident in this disclosure, the present invention provides benefits over the existing art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The illustrative embodiments of the present invention are shown in the following drawings which form a part of the specification: 
         FIG. 1  is a perspective view of a media bed float sled incorporating one embodiment of the present invention; 
         FIG. 2  is a plan view of the media bed float sled of  FIG. 1  exposing various internal features of the sled; 
         FIG. 3  is a cut away side view of the media bed float sled of  FIG. 1  without the handle attached, but with an elevated lift bag and illustrating various internal features of the sled; 
         FIG. 4  is a cut away side view of the media bed float sled of  FIG. 1  with the handle attached and rotated to approximately 45 degrees above horizontal; 
         FIG. 5  is a perspective view of the hollow frame of the media bed float sled of  FIG. 1 ; 
         FIG. 6  is yet another perspective view of the media bed float sled of  FIG. 1  partially constructed; 
         FIG. 7  is a side view of a media bed float sled of  FIG. 1  floating atop the ground by use of its air bearings and being positioned below a media box attached to a furnace; 
         FIG. 8  is a side view of the media bed float sled of  FIG. 7  lowered to the ground below the media box; 
         FIG. 9  is a side view of the media bed float sled of  FIG. 7  with its actuation bags inflated to raise the media box off of the ground to enable the ready detachment of the media box from the furnace; 
         FIG. 10  is a side view of the media bed float sled of  FIG. 7  lowered to the ground below the media box after the media box has been detached from the furnace; and 
         FIG. 11  is a side view of the media bed float sled of  FIG. 7  raised above the ground by its air bearings while supporting the media box atop the sled to enable ready lateral movement of the media box; 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION 
     In referring to the drawings, an embodiment of the novel heater system media bed (or media box) float sled  10  for a furnace, oven or kiln (collectively hereinafter “furnace”) of the present invention is shown generally in  FIGS. 1-6 , where one embodiment of the present invention is depicted by way of example. The sled  10  has a frame  12 , a pull arm  14  and a handle  16  with a grip  17  attached to the end of the pull arm  14 . As can best be seen in  FIG. 5 , the frame  12  is rectangular and constructed of a multiple lengths of straight heavy gage metal “box” tubing, preferably steel, welded together to provide the foundation for the sled  10 . The frame  12  has a flat rectangular perimeter structure  18  and a flat cross-member structure  20  within the perimeter structure  18 . The perimeter structure  18  has two opposing and parallel short sides  22  joined at right angles at their ends to two opposing and parallel long sides  24 . The perimeter structure  18  is constructed to form a continuous and interconnected hollow conduit about the frame  12 . This can be seen in  FIG. 2 , where arrows A depict the flow of compressed air within the hollow center of the perimeter structure  18 . Indeed, each weld at the corners of the perimeter structure  18  is formed so as to securely seal the interior of the structure&#39;s hollow tubing. 
     Referring again to  FIG. 5 , the cross-member structure  20  comprises a central brace  26  and a series of cross braces  28 . The central brace  26  is parallel to and equally spaced between the long sides  24  of the perimeter structure  18  and extends between and is welded to and rigidly joins the short sides  22  of the perimeter structure  18 . Four parallel and similarly spaced pairs of the cross braces  28  are welded to and rigidly join the central brace  26  to the long sides  22  of the perimeter structure  18 . Each pair of the cross braces  28  are collinear, with one cross brace  28  of each pair extending from the one side of the central brace  26  to one of the long sides  24 , and the other cross brace  28  of that pair extending from the other side of the central brace  26  to the opposite the long side  24 . In this way, the frame  12  takes on the appearance of a window having ten similarly sized rectangular panes P 1 -P 10 . While the cross-member structure  20  is welded to the perimeter structure  18  at multiple junctures and is likewise constructed of rectangular-shaped heavy gage metal “box” tubing, none of the junctures between the structures  18  and  20  breach the interior of the perimeter structure  18 . Hence, the interior of the perimeter structure  18  is isolated from the interiors of the central brace  26  and each of the cross braces  28 . The interior of the central brace  26  acts as a conduit for cables, compressed air hoses and the like. 
     Returning to  FIG. 1 , a rectangular metal top plate  30  is rigidly attached to the upper surface of the frame  12 , and has a rectangular hole  32  formed in its center. The outer perimeter of the top plate  30  is essential the same as the outer perimeter of the frame  12 , such that little or no portion of the top plate  30  overlaps the frame  12 . In addition, the top plate  30  and the hole  32  are configured such that the top plate  30  entirely covers each of four corner panes P 1 , P 2 , P 9  and P 10  of the frame  12  while exposing the six center panes P 3 -P 8  of the frame  12 . A rectangular metal lift plate  34  is positioned in the center of the upper surface of the frame  12 . Both plates  30  and  34  are constructed of heavy gage rigid metals, and preferably steel, both having the same thickness. The lift plate  34  is shaped to fit freely yet closely within the hole  32 . Thus, the hole  32  in the center of the top plate  30  is configured to receive the lift plate  34  such that the plates  30  and  34  form a generally uniform flat upper face when the lift plate  34  is placed into the hole  32 . 
     Turning to  FIG. 2 , in each of the four corner panes P 1 , P 2 , P 9  and P 10  under the top plate  30 , a spacing plate  40  is rigidly and horizontally mounted to the frame  12 . Each of the spacing plates  40  is adapted to house an air bearing  42 , which is rigidly, yet removably, mounted in a horizontal orientation in the spacing plate  40  below the top plate  30  in each of the panes P 1 , P 2 , P 9  and P 10 . Each of air bearings  42  faces downward away from the top plate  30  so as to direct compressed air supplied to the air bearing downward toward the ground under the sled  10 . Further, the thickness of the spacing plate  40  is such that the bottom of each air bearing  42  extends just slightly below the bottom surface of the frame  12  so as to enable the air bearings to properly operate. Hoses  43  operatively connect each of the air bearings  42  to air ports  44  positioned along the inner surfaces of the longs sides  24  of the frame  12 . The ports  44  open to the interior of the perimeter structure  18  of the frame  12 . In this way, the compressed air A directed into the hollow perimeter structure  18  of the frame  12  provides the compressed air supply required to operate each of the air bearings  42 . Compressed air is supplied to the interior of the perimeter structure  18  of the frame  12  through either of the connectors  45  positioned in the structure  18  near the pull arm  14 . Of course, the connectors  45  or other additional such compressed air supply connectors can be positioned at any convenient position along the perimeter structure  18 , or along the pull arm  14  or on the handle  16  with additional hosing that leads to and supplies the structure  18 . 
     Under the lift plate  34  in each of the four panes P 3 , P 4 , P 7  and P 8 , a compressed air bag  46  is mounted on top of a plate  48  rigidly mounted in a horizontal orientation to the frame  12 . A compressed air bag  46  is mounted on top of each of the plates  48 . Each of the plates  48  is positioned within the panes P 3 , P 4 , P 7  and P 8 , such that the a gap is formed between the underside of the lift plate  34  and the top side of the plates  48  having sufficient thickness for the compressed air bags  46  to set when deflated between the plates  34  and  48  without lifting the plate  34  above the plate  30 . Each of the four air bags  46  has an actuation bellows or sack  50  that is directed upward away from the mounting plates  48 . The plates  48  and air bags  46  are configured and situated in the frame  12  so as to have no pressurized engagement with the lift plate  34  when the air bags  46  are fully deflated, but to engage the lower surface of the lift plate  34  when the air bags  46  initially begin to inflate. In this way, the lift plate  34  can rest within the hole  32  in the top plate  30 , and nearly all of the vertical lift available through the air bags  46  can be applied to the lift plate  34  to raise the lift plate  34  above the top plate  30  (see  FIG. 3  showing one end of the lift plate  34  raised by an inflated actuation sack  50 ). Alternatively, the plates  48  and air bags  46  can be configured and situated in the frame  12  so as to have limited engagement with the lift plate  34  when the air bags  46  are fully deflated such that the lift plate  34  will rest within the hole  32  in the top plate  30 . 
     Additionally, a set of retention springs (not shown) can be attached to the plate  34  to the frame  12  below the plate  30  to hold the plate  34  in alignment with the hole  32  when the plate  34  is raised or lowered by the air bags  46 . Hence, while the plate  34  is otherwise free floating atop the air bags  46  when the air bags  46  are inflated, the retention springs ensure that the plate  34  rises above the hole  32  upon inflation of the air bags  46  and returns to seat in the hole  32  when the air bags  46  deflate. 
     Each of the air bags  46  has a corresponding low profile electric air compressor  52  mounted in the sled  10  that inflates and deflates the actuation sack  50 . The compressors  52  are positioned in the panes P 3 , P 4 , P 5  and P 6 , each in proximity to its corresponding air bag  46 . The compressors  52  are selected, in part, by their height such that when mounted in the sled  10 , the compressors  52  must fit below the plate  34  positioned in the hole  32 . The operation of each compressor  52  is controlled by an electric three-way switch  54  located on the upper surface of the handle  16  for ease of operation. An electric cable  56  operatively connects each compressor  52  with its respective three-way switch  54 . The actuation sacks  50  inflate when the three-way switch  54  is turned to a first position, deflate when the three-way switch  54  is turned to a second position, and hold pressure when the three-way switch  54  is turned to a third position. Hence, each of the actuation sacks  50  can be independently inflated and deflated to any level of inflation from full deflation to full inflation, by manipulation of the three-way switch  54  on the handle  16 . For compactness and protection, the compressed air hoses  56  are threaded through the interior of the handle  14  and through the interior of the central brace  26  of the frame  12 . 
     A pivot joint  60  rotationally attaches one end of the pull arm  14  to the frame  12  midway along the length of one of the short sides  22 , while the handle  16  is rigidly attached to the opposite end of the pull arm  14 . The pivot  60  allows for adjustment of the pull arm  14  for ease of use and for storage. The sled  10  is therefore very compact and has a very low profile, which allows for the positioning the sled  10  under equipment having very little clearance above the flooring. 
     Referring now to  FIGS. 7-11 , the implementation and use of the novel sled  10  is depicted. As can be appreciated, when it is desirable to move a heavy component X, such as for example a media box, that extends laterally from a furnace F, away from attachment to the furnace F at the flange B, particularly where the furnace component X must be lifted in a vertical or angular fashion before being moved laterally away from the furnace F, the sled  10  can be moved into place underneath the component X ( FIG. 7 ). 
     The initial placement of the sled  10  can be accomplished by floating the sled  10  in place under the component X with the activation of the air bearings  42 , directing compressed air  100  against the ground, or through use of other mechanical means. Thereafter, the compressed air  100  is shut off and sled  10  is allowed to rest upon the floor beneath the sled  10  under the component X ( FIG. 8 ). The air bags  46  are then inflated to raise the lift plate  34  under the furnace component X until the lift plate  34  fully engages the underside of the component X ( FIG. 9 ). It is also an option to lift the component X above the floor at this stage. Because the underside of the furnace component X may not be level, each of the air bags  46  is independently controlled so that the lift plate  34  may be moved to a position that is not parallel to the top plate  30  or the ground upon which the sled  10  is resting, but that is in full contact with the underside of the component X. The air bags  46  are then manipulated, independently if necessary, to lift the furnace component X out of engagement with the furnace F at the flange B. At this juncture, attachment such as bolts and latches, used to secure the component X to the furnace F at flange B and wedged in place due to the weight of the component X, can easily be removed or loosened to free the component X from the furnace F. 
     The air bags  46  are then deflated ( FIG. 10 ) to lower the component X resting on the lift plate  34  until the lift plate  34  is resting upon the frame  12 . The air bearings  42  are then engaged to direct compressed air  100  against the ground and raise the sled  10  which will then be supporting the furnace component X atop the lift plate  34  ( FIG. 11 ). As depicted in  FIG. 11 , the air bags  46  can also be utilized to partially raise or level the component X atop the sled  10 . The furnace component X can then be moved about easily atop the sled  10  to a desired location. Of course, these steps can be reversed to place the furnace component X onto the furnace F. Moreover, while the component X depicted in  FIGS. 7-11  rests upon the ground, it is fully contemplated that the novel sled  10  can be used in the same manner described herein to remove a component X attached to a furnace F that extends laterally from the furnace F, but does not contact the ground. 
     While I have described in the detailed description a single configuration that may be encompassed within the disclosed embodiments of this invention, numerous other alternative configurations, that would now be apparent to one of ordinary skill in the art, may be designed and constructed within the bounds of my invention as set forth in the claims. Moreover, the above-described novel media bed float sled  10  of the present invention can be arranged in a number of other and related varieties of configurations without expanding beyond the scope of my invention as set forth in the claims. 
     For example, instead of electric compressors  52  to inflate the actuation sacks  50 , compressed air may be directly supplied to each of the sacks  50 . Also, alternate lift devices, such as for example linear actuators or hydraulic cylinders, may be used instead of the air bags  46 , so long as the lift devices are capable of low profile placement on the sled  10  and can operate as the air bags  46  as disclosed herein. Moreover, there may be fewer than or more than four of the air bags  46  to lift the lift plate  34 , so long as the number is sufficient to enable the sled  10  to operate as disclosed herein. Likewise, there may be fewer than or more than four of the air bearings  42 , so long as the number is sufficient to enable the sled  10  to operate as disclosed herein. Further, insulation, such as for example high temperature pads, can be placed upon or attached to those portions of the sled  10  that may be exposed to high temperatures that could otherwise damage one or more of the components of the sled  10  without such insulation. More than one handle  14  may be attached to the sled  10 , and the handle  14  may be attached to the sled  10  at any of a variety of locations on the sled  10  nearly without limitation. The handle  14  need not be pivotally attached to the sled  10 , or may be pivotally attached with greater or less angular rotation, or may even be universally attached to the sled  10 . The shape of the sled  10 , the lift plate  34  and the frame  12 , need not be rectangular in shape, but may be other shapes, such as for example, oval, octagonal or square. The sled  10  may be of various vertical thicknesses. 
     Additional variations or modifications to the configuration of the novel heater system media bed float system  10  of the present invention may occur to those skilled in the art upon reviewing the subject matter of this invention. Such variations, if within the spirit of this disclosure, are intended to be encompassed within the scope of this invention. The description of the embodiments as set forth herein, and as shown in the drawings, is provided for illustrative purposes only and, unless otherwise expressly set forth, is not intended to limit the scope of the claims, which set forth the metes and bounds of my invention.