Abstract:
A Patio Heater Double Dome Infrared Heat Reflector/Converter is disclosed. The patio heater dome attachment is attachable to a conventional patio heater so that the dome attachment covers the heater&#39;s heat shield, while maintaining an air gap therebetween. There are preferably standoff ridges or other features built into the dome attachment to maintain this air gap and to prevent air from flowing freely between the heat shield and the dome attachment. The dome attachment embodies a very low heat load so that very little heat conduction occurs between the heat shield and the dome attachment, such that more of the heater&#39;s energy is reflected towards the usage area. Finally, the perimeter edge of the dome attachment extends downwardly at least until it is essentially horizontally planar with the perimeter edge of the patio heater heat shield.

Description:
[0001]    This application claims priority to Provisional Application Ser. No. 61/130,292, filed May 28, 2008, and is the National Stage filing of subsequent PCT Request Serial Number PCT/US09/45661, filed May 29, 2009 (within one year of said &#39;292 Provisional Application). 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    This invention relates generally to outdoor patio heating devices and, more specifically, to a Patio Heater Double Dome Infrared Heat Reflector/Converter. 
         [0004]    2. Description of Related Art 
         [0005]    Propane-fueled heaters are prevalent for heating outdoor spaces. Many restaurants and taverns provide the heaters to heat outdoor serving areas in the evenings. The typical heater used in such hospitality environments are large units that utilize a five gallon propane cylinder for fuel, although the same issue discussed herein applies to Natural Gas-fueled and Electric heaters. Residential use of these “patio” heaters has grown over the years, with a smaller, table-top version being created that is ideal for the home application. Except for scale/size, the elements of the table-top unit are essentially comparable to the full-size models.  FIG. 1  is a perspective view of a conventional (table-top) patio heater  10 . 
         [0006]    The patio heater  10  has a base  12 , within which the propane cylinder is contained. A stem  14  extends ipwardly from the base  12  to the burner  16 . The propane flow passes through the stem  14  to supply the burner  16  with fuel. Presumably for safety reasons, the burner  16  is topped by a heat shield  18 , and often surrounded by a guard  20 . The heat shield  18  is defined by a circular (typically) perimeter edge  24 , and is removably attached to the burner  16  by a securing nut  22  (or by some other fastening system). 
         [0007]    While the conventional patio heater  10  is very handy to increase personal comfort while entertaining or otherwise spending time outdoors, it does suffer from problems related to inefficiency (large fuel consumption) and environmental problems related to the combustion of the fuel. While there are heaters available that use a fixed fuel source (such a natural gas), rather than a self-contained propane tank, most heaters  10  employ a portable source. Table-top units are generally too small to have a piped-in is fuel source, and the piping would harm the utility of even having a table-top unit. With large models, the portability of the heater is lost if a permanent piped fuel source is used. 
         [0008]    For these reasons, an integrated tank is by far the most useful version of the patio heater  10 . The drawback of the tank version is that there is a finite amount of available fuel. As a result, any way to increase efficiency of the heater  10  and/or burner  16  will extend the lifespan of the fuel in a tank, and therefore reduce the number of tank exchanges. Furthermore, by increasing efficiency and by reducing fuel consumption, it is expected that the environmental concerns associated with the increasing numbers of active propane-fueled heaters would be lessened. 
       SUMMARY OF THE INVENTION 
       [0009]    In light of the aforementioned problems associated with the prior attachments and devices, it is an object of the present invention to provide a Patio Heater Double Dome Infrared Heat Reflector/Converter. The patio heater dome attachment should be attachable to a conventional patio heater so that the dome attachment covers the heater&#39;s heat shield, while maintaining an air gap therebetween. There should be standoff ridges or other features built into the dome attachment to maintain this air gap between the heat shield and the dome attachment and to keep air from flowing through freely. The dome attachment should embody a very low heat load so that very little heat conduction occurs m between the heat shield and the dome attachment, such that heater energy typically lost to the air above the heater is reflected back and radiated to the burner area, and ultimately towards the usage area as radiant heat. Finally, the perimeter edge of the dome attachment should extend downwardly at least until it is essentially horizontally planar with the perimeter edge of the patio heater heat shield. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The objects and features of the present invention, which are believed to be novel, are set forth with particularity in the appended claims. The present invention, both as to its organization and manner of operation, together with further objects and advantages, may best be understood by reference to the following description, taken in connection with the accompanying drawings, of which: 
           [0011]      FIG. 1  is a perspective view of a conventional patio heater; 
           [0012]      FIG. 2  is a partially exploded perspective view of a preferred embodiment of the present invention being attached to the heater of  FIG. 1 ; 
           [0013]      FIG. 3  is a perspective view of the attachment and heater of  FIGS. 1 and 2 ; 
           [0014]      FIG. 4  is a top view of the attachment of  FIGS. 2 and 3 ; 
           [0015]      FIG. 5  is a partially cutaway side view of the attachment of  FIGS. 2 ,  3  and  4 ; 
           [0016]      FIG. 6  is a cutaway side view of the standoff ridge of  FIGS. 2-5 ; 
           [0017]      FIG. 7  is a top view of a second preferred embodiment of the present invention; 
           [0018]      FIG. 8  is a partial cutaway side view of an uncrumple section of the attachment of  FIG. 7 ; 
           [0019]      FIG. 9  is a partial cutaway side view of a standoff dimple of the attachment of  FIG. 7 ; 
           [0020]      FIG. 10  is a partial cutaway side view of the outer edge area of the attachment of  FIG. 7 ; 
           [0021]      FIG. 11  is a top view of a third preferred embodiment of the present invention; and 
           [0022]      FIG. 12  is a partial cutaway side view of the dome member of the attachment of  FIG. 11 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0023]    The following description is provided to enable any person skilled in the art to make and use the invention and sets forth the best modes contemplated by the inventor of carrying out his invention. Various modifications, however, will remain readily apparent to those skilled in the art, since the generic principles of the present invention have been defined herein specifically to provide a Patio Heater Double Dome Infrared Heat Reflector/Converter. 
         [0024]    The present invention can best be understood by initial consideration of  FIG. 2 .  FIG. 2  is a partially exploded perspective view of a preferred embodiment of the present invention  30  being attached to the heater  10  of  FIG. 1 . The double dome attachment  30  is a secondary member designed to fit do sely above and over the heat shield  18  of the heater  10 . In the depicted heater  10  model, the securing nut  22  is unscrewed from the securing stud  26 , and the attachment  30  is then placed over the stud  26  and the nut  22  is reattached. 
         [0025]    It is known that certain patio heater manufacturers and models use a variety of bolt arrangements for securing the heat shield  18  to the heater  10 . For example, one prior model uses three studs, rather than one. These different bolt/stud arrangements are accommodated by the present invention in a couple of ways. First, the dome attachment  30  is provided with a number of apertures pre-formed in the center area of the dome attachment. Second, the user has instructions regarding forming custom apertures in the double dome attachment  30 , for those cases where the pre-formed apertures fail to align with their heater  10  model. 
         [0026]    On another point, the double dome attachment  30  is available in a variety of shapes (circular, square, etc.) and sizes (small, medium, large) so that virtually all conceivable versions of patio heater  10  available on the market today and in the future could be accommodated. 
         [0027]    If we now turn to  FIG. 3 , we can see how the heater  10  and double dome attachment  30  appear as a combination.  FIG. 3  is a perspective view of the attachment  30  and heater  10  of  FIGS. 1 and 2 . As can be seen, once secured by the securing nut  22 , the double dome attachment  30  completely covers the original equipment heat shield  18 . In this position, the attachment  30  is found to collect, reflect and re-radiate a substantial amount of heat energy that is radiated and convected upwardly from the heat shield. 
         [0028]      FIG. 4  provides additional design details of the present invention.  FIG. 4  is a top view of the attachment  30  of  FIGS. 2 and 3 . In its simplest form, the dome member  32  is made from a very thin sheet of aluminum material. The purpose of using very thin material is to minimize the thermal mass of the attachment  30 . If the thermal mass is very low, then the attachment  30  will reflect and radiate energy without retaining as much heat, thereby creating another radiant heat source. Much of the captured heat energy is returned to the radiant element, thereby increasing the heat radiating from the element as well as from the heat shield (see  FIG. 1 ). 
         [0029]    Durability or aesthetic qualities can also be enhanced by utilizing a multi-layered material for the dome member  32 . A multiple layered material will tend to be more rigid than a single thin layer of material, and will provide decorative options, such as the ability to emboss logos and other designs into the member  32 . While such options are available in a limited fashion in the single-layer version of dome member  32 , there would be additional options for the multi-layered type. 
         [0030]    The dome member  32  should be somewhat larger than the heat shield (see  FIG. 1 ) so that rising heat from combustion gases will be captured. It is preferable that there be approximately two (2) centimeters air gap between the heat shield and the dome member  32 . The overhang  38  between the double dome member&#39;s  32  perimeter edge  34  and the heat shield perimeter edge  24  (shown in dashed lines) should be such that the dome member  32  extends downwardly until its perimeter edge  34  is at least even (in a horizontal plane) with the heat shield perimeter edge  24 . As discussed previously, a central aperture  36  is provided for accepting the patio heater&#39;s securing stud therethrough. In the event that the aperture  36  is not needed, a cap may be provided to the user in order to cover the aperture  36 . 
         [0031]    In order to maximize the efficiency of the attachment  30 , there must be a slight gap between the top of the heat shield and the bottom of the attachment  30  is (discussed above as being approximately 2 centimeters). This gap is created by elements extending downward from the bottom surface of the dome member  32 . In the depicted version, these spacer elements are standoff ridges  40 A- 40 F. Each standoff ridge  40 A- 40 F is a crimped portion in the dome member  32  that rests against the top of the heat shield and maintains an air gap between the dome member and the heat shield with only a minimal amount of physical contact (in order to minimize conduction). The lower end feature of the stand-off ridge (e.g.  40 A) design is a portion of a truncated cone shape, rather than a radius, in order to allow water and other debris to escape. Here, there are six standoff ridges  40 A- 40 F; in other versions, either more or fewer ridges  40 A- 40 F might be provided. 
         [0032]    The standoff ridge  40 A design is only one simple type of structure that might be provided by the attachment  30  in order to maintain the proper spacing between the heat shield and the attachment  30 . Clips, brackets, pegs or other apparatus might also alternatively be used. 
         [0033]    Finally, we turn to  FIGS. 5 and 6  to examine the standoff ridge detail more closely.  FIG. 5  is a partially cutaway side view of the attachment  30  of  FIGS. 2 ,  3  and  4 .  FIG. 6  is a cutaway view of standoff ridge  40 E. 
         [0034]    As mentioned, the standoff ridge  40 E is formed by a plurality of bends  42  stamped or otherwise formed into the dome member  32 . The bends  42  are defined by radii R 1  and R 2 . While R 1  and R 2  could be different for different dome  30  designs, in the instant example, they are the same as one another. Here, both R 1  and R 2  are 0.5 (one-half) inch in order to form a smooth, ridge  40 E. 
         [0035]    The ridge  40 E will therefore be contoured to match the parabolic or spherical shape of the dome member  32  so that is closely mirrors the shape of the heat shield. While it has been observed that virtually all heat shields are based on these shapes, in the event that other shapes are available or enter the market, the intent would be to provide a double dome attachment  30  that matches the profile of that new shape. Also, the material chosen for the dome member  32  is selected to be a type that can be formed by the user so that it will mirror the shape of the heat shield (see  FIG. 1 ) (and perhaps even be formed or trimmed to fit by the end user). 
         [0036]    Table I below displays test data for a of conventional 40,000 BTU patio heater before and after installation of the double dome attachment  30  of the present invention. 
         [0037]    *Please note that all possible care has been taken to keep measurements precise and variables controlled. Tests were conducted using a standard “Endless Summer”(Trademark) 40,000 BTU Patio Heater under calm conditions @58 degrees Fahrenheit ambient temperature. 
         [0038]    These tests were performed with a prototype Double Dome and Heat Director made of unpolished 0.025″ aluminum sheet. Thinner and/or more reflective aluminum perform more effectively. 
         [0000]    
       
         
               
             
               
               
               
               
             
           
               
                   
               
               
                 Percentage of Fuel Savings @ Highest Stock Temperatures** 
               
             
          
           
               
                 Measurements in 
                   
                 With 
                 % of Gas Savings 
               
               
                 Degrees 
                   
                 Double 
                 W/Dome at stock 
               
               
                 Fahrenheit 
                 Stock 
                 Dome 
                 temperature. 
               
               
                   
               
               
                 Radiant Collector @ 
                 135 
                 166 
                 29% 
               
               
                 32″ 
                   
                   
                   
               
               
                 Top of Burner 
                 782 
                 906 
                 34% 
               
               
                 Holder 
               
               
                   
               
               
                 **Gas Savings are computed by drawing a horizontal line across the graph from the highest stock temperature at maximum consumption temperature on the line with the device installed. Divide the gas consumption at that temperature, using that device stock by 6.5 (the maximum gas consumption at that temperature) to obtain the percentage of “stock” consumption at that temperature, using that device. 100% − Percentage Consumed = Percentage Saved. See notes below for the calculations. 
               
               
                 Math Notes: 
               
               
                 Percentage of Fuel Saved by Temperatures @ the radiant collector: 
               
               
                 % of Gas Savings W/Dome 
               
               
                 4.6 (0.046 m 3  per minute)/6.5 (0.065 m 3  per minute) = 71% consumption, 
               
               
                 100% − 71% = 29% Fuel Savings 
               
               
                 Percentage of Fuel Saved by Temperatures @ the Top of the Burner Holder: 
               
               
                 % of Gas Savings W/Dome 
               
               
                 4.3 (0.043 m 3  per minute)/6.5 (0.065 m 3  per minute) = 66% consumption 
               
               
                 100% − 66% = 34% Fuel Savings 
               
             
          
         
       
       
      
     
         [0039]    As shown here, the heater actually produced a significantly higher temperature after installation of the double dome attachment  30  at both high and low settings. The user can choose to throttle back the fuel flow to the heater by twenty-five to thirty percent, and still enjoy the same radiant heat output to the area of use as an unmodified heater that is not so throttled back. Consequently, the fuel tank will be expected to last twenty-five to thirty percent longer than the prior standard heater, and will provide the environmental benefits of less fuel consumed and less carbon emissions. 
         [0040]    A second preferred embodiment of the attachment  30  of the present invention is depicted in  FIG. 7 , which is a top view of the present invention. The dome  32  of this version of the attachment  30  will be made from very thin aluminum (preferably in the range of 0.006 to 0.008 inches thick), and have a bright, shiny finish. Instead of standoff ridges (see previous figures), this version  30  has a plurality of standoff dimples  72  dispersed around the dome  32 . It should be understood that certain (non-depicted) versions may have a variety of standoff protrusions (whether ridge-shaped, dimple-shaped, or other shapes) 
         [0041]    This embodiment  30  is designed to ship flat, but allow the user to place it over the heater (see  FIGS. 1 and 2 ), and then pull it down until it fits the shape of the heat shield (see  FIGS. 1 and 2 ). This functionality is possible because the dome  32  is configured to have alternating uncrumple sections  74  and smooth sections  75 . The standoff dimples  72  are formed in the smooth sections  75 . the uncrumple sections  74  have concentric “waves” or creases formed in them in order to allow the user to re-shape the contour of the dome  32 , as appropriate. 
         [0042]    There is a center dimple  73  that is designed to be detachable from the dome member  32 . Essentially, the central dimple  73  is a standoff dimple  72  that has a bottom that can be popped out. This design accommodates a wide variety of patio heaters (see  FIGS. 1 and 2 ), since some heaters do not have a central attachment bolt (see  FIG. 2 ), and some do. Whether or not a central attachment bolt exists on the heater (see  FIGS. 1 and 2 ), the attachment  30  will be held (at least in part) to the heat shield (see  FIG. 2 ) by a plurality of securing clips  70  that extend downwardly from the outer edge of the attachment  30 , as discussed below in connection with the description of  FIG. 10 . 
         [0043]    In this exemplary version  30 , there are also reinforcing clips  85  attached to m the outer edge of the dome member  32  in ceder to provide additional reinforcing strength to each securing clip  70 .  FIG. 10  depicts these reinforcing clips  85  in a cutaway side view. 
         [0044]      FIG. 8  is a partial cutaway side view of an uncrumple section  74  of the attachment of  FIG. 7 . As shown, the section  74  is made of a series of circular, concentric creases  76  that will permit “stretching” and compression of the dome member (see  FIG. 7 ) to fit a heat shield (see  FIG. 2 ). The creases  76  could be made from smooth bends, as shown, or other shapes, as desired. 
         [0045]      FIG. 9  is a partial cutaway side view of a standoff dimple  72  of the attachment of  FIG. 7 . Essentially, the standoff dimples  72  have the same shape as the standoff ridges (see  FIGS. 4 and 6 ), but in the form of a circle, rather than an elongate ridge. The dimples  72  will provide the same functionality as the ridges (see  FIGS. 4 and 6 ). 
         [0046]    Finally,  FIG. 10  is a partial cutaway side view of the outer edge area of the attachment of  FIG. 7 . The attachment clips  70  are bendable metal strips extending inwardly from the outer edge of the dome member  32  and covered by a reinforcing clip to strengthen the attachment of the securing clips. In the depicted version, there is a peripheral ring stabilizer  78  captured within a fold  80  formed in the outer edge of the dome member  32 . The ring stabilizer  78  serves to stiffen the dome member  32  so that it will be sufficiently durable and will not be affected by wind or other inclement weather. 
         [0047]    The clips  70  are preferably captured within the foil  80  formed around the ring stabilizer  78  and reinforced with an external clip or ring. The clips  70  can be bent to fit the under surface of the heat shield (see  FIGS. 1 and 2 ), to hold the attachment (see  FIG. 7 ) securely in place. 
         [0048]      FIGS. 11 and 12  depict a third embodiment of the attachment  30  of the present invention.  FIG. 11  is a top view of the third embodiment  30 , and  FIG. 12  is a partial cutaway side view of the dome member  32  of this version  30 . Here, the dimples  72  are formed as sort of a hybrid between those depicted in  FIG. 4 , and those depicted in  FIG. 8 , that is to say that they are somewhat elongated, rather than circular. Also, the bottom of the dimples  72  will tend to have a somewhat flattened bottom in order to promote drainage of incident water and the like. 
         [0049]    Another distinction in this version  30  is that there are a plurality of central dimples  73  at a variety of different distances from the center of the dome member  32 . Each of these dimples  73  has an downwardly-protruding dome that can be perforated, if desired, in order to accommodate a mounting bolt passing therethrough (i.e. from the patio heater—see  FIGS. 1 and 2 ). 
         [0050]    Finally, and as depicted in  FIG. 12 , the smooth sections  75  of this version  30  are curved to the same contour as the smooth section at the center of the dome member  32 . The uncrumple sections  74  will incline (as shown) when the dome member  32  is in a flattened condition, but will be contoured to fit the heat shield (see  FIGS. 1 and 2 ) when the attachment  30  is attached to the patio heater (see  FIGS. 1 and 2 ). 
         [0051]    Those skilled in the art will appreciate that various adaptations and modifications of the just-described preferred embodiment can be configured without departing from the scope and spirit of the invention. Therefore, it is to be understood that, within the scope of the appended claims, the invention may be practiced other than as specifically described herein.