Patent Publication Number: US-2009235919-A1

Title: Screen for gas fireplace window

Description:
This application claims priority to Canadian Patent Application XXXXXXXX, filed 20 Mar. 2008, the specification of which is hereby incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to gas-burning fireplaces. In particular, this invention relates to a means of preventing the buildup of milky film on the inside of the transparent front panel of a gas-burning fireplace. 
     2. Description of the Related Art 
     A common but persistent problem with gas-burning fireplaces is the buildup on the inside surface of the front window of a milky or hazy film. The film detracts from the appearance of a fireplace and from the ability to appreciate the fire within. 
     While the cause of the film is not clearly known, some manufacturers have speculated that it is the result of the curing process of the paint and log sets used in the fireplaces. It has also been suggested that the white film deposit arises from additives used in the gas and reference has been made in industry literature to a mineral residue left from water vapor as the gas burns. Regardless of the cause, the film is perceived to be a problem and detrimental to the look of the fireplace. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention offers a solution to the film problem in gas fireplace windows. 
     The inventor has found that providing a mesh screen spaced a short distance from the inside surface of the transparent front panel of a gas-burning fireplace has the effect of preventing or alleviating the buildup of the film. 
     It is postulated that the effectiveness of the invention is due to the interruption or modification of the air flow from the inside of the fireplace towards the inside surface of the panel. However, the preferred and other contemplated embodiments are effective and the claims made herein are not dependent on a definitive understanding of why the invention works. 
     The foregoing was intended as a broad summary only. It was not intended to define the limits or requirements of the invention. Various aspects of the invention will be appreciated by reference to the detailed description of the invention and to the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described by reference to the detailed description of the invention and to the drawings thereof in which: 
         FIG. 1  is an illustration of the undesirable white film on the window panel of a gas-burning fireplace; 
         FIG. 2  is a front view of an embodiment of the invention; 
         FIG. 3  is a cross-section taken along line  3 - 3  of  FIG. 2 ; 
         FIG. 4  is a detail cross-section of the means of securing the top of the screen to the window panel frame; 
         FIG. 5  is a front view of the mesh used in an embodiment of the invention; and, 
         FIG. 6  is a perspective exploded view of an embodiment of the invention in a gas fireplace. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  illustrates the milky white haze or film  10  that tends to build on the inside of the window panel  12  of gas-burning fireplaces  14 . 
       FIGS. 2 ,  3 ,  4  and  6  illustrate an embodiment of the invention. According to the invention, a screen  16  is provided so as to substantially span the inside surface of the window panel  12  of the gas fireplace  14 . As can be appreciated by reference to  FIG. 4 , the screen  16  is spaced from the inside surface  18  of the panel  12  by a short distance “d”. The screen  16  lies in a plane  20  that is substantially parallel to the plane  22  of the panel  12  so that a reasonably consistent spacing d between the panel and the screen is maintained. In one or more embodiments, the distance d is between ¼ and 1 inch but may be as much as 8 inches. 
     Referring to  FIG. 4 , the screen  16  is secured by means of a bent portion  24  of the peripheral screen frame  26  that is seated in a gap  28  between the window panel  12  and an inside shoulder  30  of the frame of the fireplace. It is contemplated that the screen can be made removable for replacement or cleaning if necessary. 
     Referring now to  FIG. 5 , the mesh size  40  of the screen  16  in one or more embodiments is approximately ¼ inch. However, it is contemplated that the mesh size will be effective between 1/16 and ⅜ of an inch. 
     In one or more embodiments, the screen is made of steel wire cloth mesh but other materials that are capable of withstanding the environmental conditions in the fireplace are likely to be equally effective, including notably Teflon™-coated fiberglass. 
     The parameters of mesh size and spacing d that will be effective for the purposes of the invention will be dependent on the size of the fireplace, the distance of the burners and log sets from the front panel and the air and gas flows within the fireplace. These vary with different fireplace designs and configurations, but in one or more embodiments and ranges discussed herein should be effective for the majority of commercial gas fireplaces on the market. 
     It will be appreciated by those skilled in the art that the embodiments have been described in some detail but that certain modifications may be practiced without departing from the principles of the invention.