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[0001]    The application claims priority from U.S. provisional Application No. 60/352,598. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention relates to heating apparatus and systems using such apparatus.  
         BACKGROUND OF THE INVENTION  
         [0003]    It is well known that ice build up on planar surfaces such as roofs may cause physical damage to the structure and also pose a hazard to people passing near to such structures. Typically the build up of ice and snow on a building is caused by localised freeze and thaw cycles that generates an ice dam at a particular locations along the roof These ice dams prevent the drainage of the roof and may cause penetration of moisture through the roof if left unattended.  
           [0004]    It is known to provide localised heating at the edge of the roof by a heating cable secured to the roof by clips. The heating cable can be activated to melt any accumulation of ice and snow that may occur on the edge of the roof. With such installations, the cable is left relatively exposed and the effect of the heating cable is localised. For this reason a serpentine installation is frequently used to extend the area over which heat is applied.  
           [0005]    However the heating effect achieved from the cable is relatively local and leaves the cable exposed to damage from the snow, ice and other external factors.  
           [0006]    It is therefore an object of the present invention to provide a heating apparatus to obviate or mitigate the above disadvantages.  
           [0007]    In general terms, the present invention provides heating apparatus comprising a body of conducting material having a pair of laterally spaced edges, oppositely directed surfaces extending between said edges, a channel formed on one of the surfaces and defined by a pair of walls upstanding from said one surface, and a cover co-operating with the walls to define an enclosed passageway to receive a heating cable.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings in which:  
         [0009]    [0009]FIG. 1 is a perspective view of a house;  
         [0010]    [0010]FIG. 2 is a perspective end view of a heating apparatus for installation on the house of FIG. 1;  
         [0011]    [0011]FIG. 3 is an enlarged view of a portion of the heating apparatus shown in FIG. 2;  
         [0012]    [0012]FIG. 4 is a side view of the heating apparatus of FIGS. 2 and 3 installed on a roof of the house of FIG. 1;  
         [0013]    [0013]FIG. 5 is a end view similar to FIG. 2 of an alternate embodiment;  
         [0014]    [0014]FIG. 6 is a view similar to FIG. 4 utilising the embodiment of FIG. 5;  
         [0015]    [0015]FIG. 7 is a perspective view of a further embodiment of heating apparatus;  
         [0016]    [0016]FIG. 8 is a perspective view of a still further embodiment of the apparatus;  
         [0017]    [0017]FIG. 9 is a perspective view of a further embodiment of the apparatus;  
         [0018]    [0018]FIG. 10 is a schematic representation of an alternative use of the apparatus shown in FIG. 9; and  
         [0019]    [0019]FIG. 11 is a perspective view of a further embodiment of the heating apparatus.  
         [0020]    [0020]FIG. 12 is a perspective view of a further embodiment applied to a pipe. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0021]    Referring therefore to FIG. 1, a house  10  has a roof  11  formed in part by a pair of intersecting roof panels  12 ,  14  which define a valley  16  at their intersection. A dormer window  18  is located in the roof to define further valleys  20  at its intersection with the plane of the roof  12 . An eavestrough  22  extends around the lower periphery of the roof and has a pair of down spouts  24 ,  26  to convey water from the eavestrough  22  to the ground.  
         [0022]    A number of areas on the roof  11  of house  10  pose a significant risk of ice build up due to various environmental factors including freeze/thaw cycles or the loss of heat from the house itself. To avoid the ice build up the heating apparatus shown in FIGS. 2 through 11 is utilised on different areas on the house as will be described more fully below.  
         [0023]    Referring therefore to FIG. 2, a heating apparatus  30  has an elongate body  32  with upper and lower faces  34 ,  36 . The body  32  extends between a pair of laterally spaced edges  38 ,  40  and tapers from a tip  38  to a butt end  40  such that the spacing between the surfaces  34 ,  36  progressively increase from the tip  38  to the butt end  40 . As can be seen more clearly in FIG. 3, a pair of upstanding barbs  42  are integrally formed adjacent the butt end  40  on the upper surface  34 . The barbs  42  are undercut as indicated at  44  to allow a cap  46  to be secured to the body  32 .  
         [0024]    The cap  46  is generally D-shaped with a pair of limbs  48  extending from an intermediate portion  50 . The outer surface of the cap  46  is ribbed as indicated at  52  to increase the surface area of the outer surface of the cap. The lower end of the limbs  48  have barbs  54  complimentary to the undercut  44 . Each of the barbs  42 ,  54  are shaped to permit the cap  46  to be engage with and be snapped onto the barb  44  to retain the cap on the body  32 .  
         [0025]    The cap  46  and body  32  co-operate to define a cavity  56  within which is located a heating cable  58 . The heating cable  58  is of known design and is of a self regulating construction with a pair of conductors  60  electrically connected by a carbon filament  62 . The cable includes a protective outer sheath  64  and operates to provide a heating effect that is proportional to the ambient temperature. Thus the lower the temperature from a pre-set meld point the greater the heating effect. Such a cable is well known and is available from Heat-Line Corporation, Canarvon, Ontario under the trade-mark Paladin I.  
         [0026]    The body  32  and cap  46  are formed from a highly conductive material, typically aluminium. The body  32  is dimensioned to coincide with the dimensions of courses of shingle applied to the roof panels  12  and  14 . In a typical application, the body  32  is in the order of 6.65 inches from the tip  38  to the butt end  40  with the barb  42  closest to the tip  38  spaced 0.7 inches from the butt end  40 . The length of the body  32  may be of any convenient length, typically 4 foot lengths and the thickness of the body  32  at the butt end  40  is in the order of 0.1 of an inch. The cavity  56  will typically be in the order of 0.65 inches between the barbs and in the order of 0.25 deep. These dimensions are of course typical and may vary according to particular applications or physical dimensions. Typically the body  32  and cap  46  may be extruded and subsequently cut to length to suit. A suitable aluminium alloy is 6063 T5 although other alloys may be utilised. The outer surfaces  34 ,  36  of the body  38  may be covered by barrier materials such as Mylar to inhibit galvanic corrosion when used in combination with metal roofing or fastenings.  
         [0027]    The apparatus  30  is installed on the roof panel  12  at a location proned to ice build up. As indicated in FIG. 4, this may be at a location spaced from the lower edge of the roof panel  12 . The apparatus  30  is installed by lifting a shingle  70  to expose the underlying shingle and the body  32  then secured by a screw  72 , nail or adhesive or other fastening to the underlying shingle and roof deck  74 . The apparatus  30  is positioned so that the cap  46  is adjacent to the lower end of the shingle  70  and will run horizontally along the lower edge of the run of shingles. The shingle  70  may then be replaced to cover the body  38  with the tapered cross-section of the body  38  providing a minimum disturbance to the line of the shingles. After installation, the cable  58  is located between the barbs  42  and the cap  56  then snapped into place. The end of the cable is connected to a suitable power source on the outside of the house and may in fact be fed within the down spouts  24  to provide a heating effect and maintain the down spouts clear of ice.  
         [0028]    Sufficient of the apparatus  30  is installed to extend along the roof panel in the area where the ice is likely to form. The apparatus  30  are laid end to end with a small gap between adjacent units to permit contraction and expansion.  
         [0029]    In operation, power is supplied to the cable  58  that provides a self regulating heating effect within the channel  56 . The heat is transferred through the body  32  beneath the shingle  70  which is in contact with the upper surface  34 . The heat is thus transferred over a substantial area through the shingle and into the ice or snow causing it to melt and drain down the roof. As the temperature fluctuates, the heating effect similarly fluctuates and an ice free roof panel is maintained under varying conditions. Naturally, the power source may be used intermittently or may be left in with its self regulation providing economical use of electricity.  
         [0030]    As illustrated in FIG. 4, the apparatus  30  is installed away from the edge of the roof panel  12 . An alternative embodiment as shown in FIG. 5 is particularly useful for use at the edge of the roof panel and like components will be identified with like reference numerals with a suffix “a” added for clarity. In the embodiment of FIG. 5, the body  32   a  of the apparatus  30   a  is cranked as indicated at  80  between the tip  38   a  and butt end  40   a  A cap  46   a  is secured on barbs  42   a . The crank  80  will typically provide an included angle in the order of 140° and is spaced in the order 5.6 inches from the tip  38   a.    
         [0031]    The heating apparatus  30   a  is installed in the manner shown in FIG. 6 is similar to the shown in FIG. 4. The body  32   a  is located beneath the first run of shingles  70   a  with the crank  80  located on the edge of the sheathing  72   a . The chamber  56   a  thus depends below the lower edge of the shingles and provides a heating effect at the edge of the roof panel  12  which is transferred through the body  32   a  into the lower most run of the shingles  80   a . Again the broad band effect of the heating enables the lower edges of the roof panel to be maintained free of ice and the cable  58   a  located securely within the channel  56   a  below the sight line of edge of the roof  11 .  
         [0032]    The valley areas  16 ,  20  are also susceptible to the build up of ice and the embodiments shown in FIGS. 7 and 8 are useful in these locations. Again like components will be identified with like reference numerals with a suffix “b” and “c” respectively provided for clarity. In FIG. 7, the body  32   a  extends on either side of the cap  46   b  and is cranked to provide an inclination corresponding to the included angle in the valley  16 . The relatively malleable nature of the aluminium alloy facilitates the adjustment of the inclination so as to match the included angle with each of the bodies  32   b  tapering towards their tips  38   b . The cap  46   a  is secured as a snap fit on barbs  42   b  so that the heating table  58  may pass along the cavity  56   b  along the axis of the valley  16 . Thus heat is transferred through the bodies  32   b  into the adjacent shingles as well as the valley itself to promote the thawing of ice build up in that location.  
         [0033]    The embodiment of FIG. 8 is particularly useful in the valleys  20  where walls may intersect at 90°. Bodies  32   c  extend from either side of a channel  56  formed between the cap  46   b  and an apex defined by the intersection defined by the bodies  32   c . Barbs  42   c  project upwardly from each of the bodies  32   c  to allow a snap fit of the cap  46   c . The unit  30   c  may thus be fitted adjacent the walls in the valleys  20  to provide a heating effect on the lower edge of the wall and the adjacent shingles.  
         [0034]    In a further embodiment shown in FIG. 9, the body  32   d  extends to either side of the channel  56   d  but is essentially planar so it may be fitted to a horizontal surface such as a flat roof to provide drainage channels. The unit  30   d  is particularly useful in maintaining eavestroughs clear of ice, particularly the wide eavestroughs found on commercial and industrial buildings.  
         [0035]    The embodiment of FIG. 9 may also be used to provide a heating effect to walkways or floors by being placed side by side as shown in FIG. 10 beneath the floor. The apparatus  30   d  is embedded within a mortar  84  and capped with a wear surface  86 . The cables may then be run through the channels  56   d  with the bodies  32   d  distributing the heating effect over a wide area through the mortar and to the overlay  86 .  
         [0036]    The heating effect of the cables  56  may also be incorporated into a snow fence for use on roofs as indicated in FIG. 11. Snow fences are used to inhibit the discharge of snow from roofs en masse. As shown in FIG. 11, a heating apparatus  30   e  includes a body  32   e  extending from a tapered tip  38   e  to the butt end  40   e . A pair of supports  100  extend upwardly from the upper surface  34   e  adjacent the butt end  40   e . The supports  100   e  carry a pair of channel members  102  extending horizontally parallel to the butt end  40   e . The channels include a pair of barbs to receive a cap  46   e  and define an enclosed channel. The cable  58   e  is located within the channel  102  and secured by the cap  46   e.    
         [0037]    Upon application of power, the heat of the cable is transferred through the channel members  102  and supports  100  into the body  32   c . A controlled discharge of the snow held by the fence provided from the supports  100  in channel members  102  is provided with progressive thawing as the heat is applied through the cables.  
         [0038]    In a further embodiment shown in FIG. 12, the heating apparatus  30   f  is used in conjunction with a ductile pipe  104 , such as may be used for soil or waste water. As can be seen in FIG. 12, the body  32   f  of the apparatus  30   f  is curved to conform to the outer surface of the pipe  104 . A channel  106  is formed on the outwardly directed convex surface to receive a cable  58   f  and is closed by a top cap  46   f.    
         [0039]    The body  32   f  tapers towards the opposite lateral edges and is held in situ by bands  110  or other suitable fasteners. In use, the bodies  32   f  are aligned along the pipe  104  over the area to which the heat is applied. The channels  106  are aligned so the cable may run along the length of the pipe  104  and transfer heat through the body  32   f  to the walls of the pipe  104  over an extended area.  
         [0040]    If preferred, the cable may be inserted after the pipe has been buried or covered by using the channel as a race for the cable.  
         [0041]    Although the invention has been described with reference to certain specific embodiments, various modifications thereof will be apparent to those skilled in the art without departing from the spit and scope of the invention as outlined in the claims appended hereto.

Summary:
Heating apparatus comprising a body of conducting material having oppositely directed surfaces extending between the edges, a channel formed one of the surfaces and defined by a pair of walls upstanding from the one surface, and a cover cooperating with the walls to define an enclosed passageway to receive a heating cable.