Abstract:
A burner for use with fireplace gas logs includes a burner pan having a gas burner extending across it. A flame control plate is located in the burner pan above the burner. The flame control plate has an opening located in it which is partially covered by a damper. The damper can be moved to cover various portions of the opening which allows directing the burner flame to give the desired effect in the fireplace logs. By installing the burner assembly in a particular manner the fireplace logs can be made to look substantially like real burning logs.

Description:
BACKGROUND OF THE INVENTION 
   The subject invention relates to a burner assembly for use with ceramic fireplace gas logs, and to a method of constructing a log set on the burner assembly in a manner that provides a more natural appearance when burning. 
   Fireplace logs are often used in fireplaces or fire pits to give the appearance of real logs. A burner pan having a burner which burns natural gas or propane is placed under the fireplace logs to create a flame which passes through the logs to give them the appearance and effect of burning wood. While the logs themselves are quite realistic, the manner in which the logs are installed typically does not create a realistic appearance when the logs are burning. In addition, prior art fireplace logs are installed in a manner such that most of the flame is at the back or center of the logs where it provides little radiant heat. 
   SUMMARY OF THE INVENTION 
   The subject invention overcomes the shortcoming of the prior art fireplace logs by providing a burner assembly for fireplace log sets having a burner pan with a burner extending across it and a flame control plate which is located in the burner pan above the burner. The flame control plate has an opening, a portion of which can be selectively closed with a damper. The invention also covers a method for using this burner assembly to make fireplace logs look like real logs when burning. 
   The foregoing and other objectives, features, and advantages of the invention will be more readily understood upon consideration of the following detailed description of the invention taken in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE SEVERAL DRAWINGS 
       FIG. 1  is a perspective view of a prior art burner pan. 
       FIG. 2  is a perspective view of the burner assembly of the subject invention with the flame control plate in its closed or operative position. 
       FIG. 3  is a perspective view of the burner assembly of  FIG. 2  with the flame control plate rotated to an open position. 
       FIGS. 4–6  show how the damper can be adjusted to cover varying portions of the opening in the flame control plate. 
       FIGS. 7–13  show the method of installing a fireplace log set over the burner assembly of  FIG. 2 . 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
   A burner assembly  10  includes a burner pan  12  having a planar rectangular base  14  with an upright rectangular back  16  and opposed upright triangular sides  18 . A burner  20 , which extends across the burner pan, is connected to a source of burnable gas, such as natural gas or propane (not shown), through a supply pipe  22 . A series of holes (not shown) located in the bottom of the burner allow the gas to flow out of the burner along its entire length. As shown in  FIG. 1 , burner pans of this type are well known in the prior art. The exact shape of the burner pan can vary and other shapes can be used. The size of the burner pan will vary based on the application. Burner pans of this type are used to supply a distributed flame along their extent for burning fireplace logs in fireplaces, inserts and open fire pits. 
   Referring now to  FIGS. 2 and 3 , located in the burner pan  12  is a flame control plate  24 . The flame control plate is shown as rectangular but could have other shapes depending on the shape of the burner pan it is installed in. The flame control plate is attached to the back  16  of the burner pan by a pair of hinges  25  which allows it to be rotated between an operable position,  FIG. 2 , where it extends over the burner  20 , and a raised position,  FIG. 3 , where the burner  20  is exposed. The flame control plate illustrated has legs  26  which depend from each of its ends and cause it to be positioned slightly above the burner when it is in its operating position. 
   Located in the rear center portion of the flame control plate is an opening  28 . The opening  28  is preferably located mostly behind the burner  20 , but the front edge of the opening can extend over or slightly in front of the burner. In the embodiment illustrated the opening is elongate and is progressively wider moving toward its center. A damper  30 , which is releasably mounted to the flame control plate, partially covers the opening  28 . In the embodiment illustrated the damper is rectangular, but its shape could vary depending on the shape of the opening and the shape of the flame control plate. The damper is attached to the flame control plate by a screw  32  which fits loosely through a hole (not shown) in the damper and threads into one of a series of holes  34  in the flame control plate. The holes  34  are located forwardly of the center of the opening  28 . By having multiple holes  34  the amount of the opening covered by the damper, and the amount of flame positions through the log set, can be varied as shown in  FIGS. 4 and 5 . This allows varying the location of the flame front to rear on the log set. Having a single attachment point through the screw  32  allows the damper to be rotated about the screw and have more open area on one side of the opening than the other as shown in  FIG. 6 . This adjustment in conjunction to the opening  28  becoming progressively wider moving toward its center allows varying the location of the flame side to side along the log set to create a natural-appearing burn and to overcome a tendency of the flame to primarily be on one side. 
   Also located in the flame control plate are a series of small openings  36  which are located around the opening  28 . The small openings  36  are located on each side and in front of the opening  28  to allow some of the flame to extend across the entire log set. However, because the opening  28  is much larger than the openings  36 , the majority of the flame will be at the center of the logs, as it is with real wood logs. 
   Referring now to  FIG. 4 , before the burner assembly  10  is placed on a burning surface sand  38  is spread on top of the burning surface. The sand creates a base which prevents the burner assembly from moving around. After the burner assembly is in place and the supply pipe  22  has been connected to a source of burnable fuel, the burner assembly and the area surrounding the burner assembly are filled with vermiculite  40  or a similar material,  FIG. 5 . A grate  42  is then placed over the burner assembly. More vermiculite  40  is placed on and around the burner assembly to completely cover the burner assembly and to partially cover the grate, primarily its front portion,  FIG. 7 . 
   The vermiculite is then covered with a thin layer of zonalite  44 . The front of the grate  42  is then covered with a layer of thermal fiber  46 ,  FIG. 7 , and the fireplace log set  48  is built on the grate  42 ,  FIG. 8 . 
   Once the log set  48  has been built on the grate  42 , more thermal fiber  46  is used to cover any openings between the lower front log  48   a  and the vermiculite/zonalite base. A pitch-like glue  50  can be applied to selected locations on the fireplace logs and more thermal fiber  46  adhered to the glue,  FIG. 9 . The thermal fiber  42  on the logs is then painted with a high temperature paint  52 , which preferably is black or a dark color which appears essentially black, and vermiculite  40  and/or zonalite  44  is placed on top of the paint before it dries,  FIG. 10 . Openings  54  no more than ½ inch wide are cut in the thermal fiber  46  located at the front of the bottom log  48  with a knife or other sharp object to allow a small amount of the flame to go in front of the logs and create an ember effect. 
   Decorative rock  56  can be placed in front of the log set. If desired, the rock can be covered with paint  52  and vermiculite  40  and/or zonalite  42  can be applied to the paint before it dries. The burner is then lit to see how the flame penetrates the log set, and, if necessary, the damper  30  can be adjusted to create the desired flame pattern. 
   The purpose of the burner assembly and the method of installing it is to force the flame toward the front and center of the logs where more of the heat generated by the flame will be radiated into the room. With the prior art most of the flame is at the back or center of the logs and the majority of the heat it generates is lost up the chimney. The legs  26  cause the front of the flame control plate to be raised so that more of the flame will be at the front of the logs. However, this alone would cause a large portion of the draft caused by the burning fireplace to be drawn under the logs which would tend to negate the effect of the flame being forced to the front of the log set. Thus, it is important that the vermiculite  40  and thermal fiber  46  completely cover any open space at the front of the logs with only the small openings  34  in the thermal fiber to create an ember effect below the logs. 
   When heated the thermal fiber covered with vermiculite and/or zonalite glows much like ambers on real burning logs, giving an appearance of natural burning logs. In addition it allows the flame to pass almost completely through the logs rather than around them, which creates the appearance of real burning logs. The overall result is that when burning the log set appears far more realistic than is normally the case with fireplace logs. 
   The terms and expressions which have been employed in the foregoing specification are used therein as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding equivalents of the features shown and described or portions thereof, it being recognized that the scope of the invention is defined and limited only by the claims which follow.