Abstract:
A heat deflection member having a first bend along a central axis of the heat deflection member that forms first and second opposing panels, and opposing first and second parallel edges of the heat deflection member having second and third bends formed parallel the central axis that form opposing first and second coupling flanges along at least a portion of a length of the opposing edges. A method of manufacturing a fireplace baffle and a pre-fabricated fireplace are also provided.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Application Ser. No. 61446939, filed by Joseph A. Benedetti on Feb. 25, 2011, entitled “IMPROVED LINEAR FIREPLACE WITH BURNER,” commonly assigned with this application and incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    This application is directed, in general, to a prefabricated fireplace and, more specifically, to a flue baffle for a gas prefabricated fireplace. 
       BACKGROUND 
       [0003]    Some modern pre-fabricated fireplaces may be made so as to have two opposing hearths wherein each may be in separate interior rooms, or one may be in an interior room and the other directed to a patio or outdoor living area. With this arrangement, the fire is centrally located within the firebox and serves both hearths. These may be referred to as “See Thru” fireplaces. Often these fireplaces may have no damper in a centrally-located, common flue as well as having two screens/glass fronts, each one facing one of the hearths. Under normal circumstances, the absence of a damper would allow much radiant and convective heat to be lost up the central flue along with the fire by-products. To minimize the loss of radiant and convective heat up the flue, as well as to hide what might be considered an esthetically-undesirable, open flue, conventional baffles have been provided. These conventional baffles are not adequate to disperse or redirect, in a controlled fashion, the heat produced so as to accommodate the input BTU rate required for the fireplace assembly. Reflecting radiant heat back toward the floor of the firebox generally increases the heat that the firebox floor must absorb, and consequently limits the BTUs of the fireplace assembly. 
       SUMMARY 
       [0004]    One aspect provides a heat deflection member having a first bend along a central axis of the heat deflection member that forms first and second opposing panels, and opposing first and second parallel edges of the heat deflection member having second and third bends formed parallel the central axis that form opposing first and second coupling flanges along at least a portion of a length of the opposing edges. 
         [0005]    Another aspect provides a method of manufacturing a fireplace baffle comprising forming a heat deflection member having a first bend along a central axis of the heat deflection member that forms first and second opposing panels, and forming second and third bends parallel the central axis that form opposing first and second coupling flanges along at least a portion of a length of opposing first and second parallel edges of the heat deflection member. A prefabricated fireplace assembly is also provided. 
     
    
     
       BRIEF DESCRIPTION 
         [0006]    Reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which: 
           [0007]      FIG. 1  is a plan view of one embodiment of a fireplace baffle  100  constructed in accordance with the present disclosure; 
           [0008]      FIG. 2  is a sectional view of one embodiment of a fireplace baffle  100  of  FIG. 1  along plane  2 - 2 ; 
           [0009]      FIG. 3  is a sectional view of an alternative and preferred embodiment of a fireplace baffle  300  along plane  2 - 2  of  FIG. 1 ; 
           [0010]      FIG. 4  is a vertical sectional view of a prefabricated fireplace  400  along the centerline  130  of  FIG. 1 ; 
           [0011]      FIG. 5A  is a front elevation view of a prefabricated fireplace constructed in accordance with the present disclosure; 
           [0012]      FIG. 5B  is a vertical sectional view of a prefabricated fireplace constructed in accordance with the present disclosure; and 
           [0013]      FIG. 6  is a chart of average temperatures of cabinet, flue and selected surroundings collected with thermocouples at locations within and without one representative prefabricated fireplace with each of the four baffle configurations. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    Referring initially to  FIG. 1 , illustrated is a plan view of one embodiment of a fireplace baffle  100  constructed in accordance with the present disclosure. In the illustrated embodiment, the fireplace baffle  100  comprises a sheet-metal, heat deflection member  110  having first and second parallel edges  111 ,  112  and a first bend  121  along a centerline  130  thereof, and second and third bends  122 ,  123 , parallel the first and second parallel edges  111 ,  112 , thereby forming first and second opposing panels  141 ,  142 , and first and second parallel mounting flanges  151 ,  152 . As used herein, the term “bend” includes not only those instances where sheet metal is mechanically bent, but it also includes those instances where the bend is formed by welding, brazing, or otherwise attaching individual pieces of metal together. The term “bend” also includes forming the bend in a moldable material, such as a ceramic or similar material, that can be used to produce the heat deflection member  110 . In certain embodiments, the fireplace baffle  100  may also comprise a plurality of mounting apertures  160  distributed along the first and second mounting flanges  151 ,  152 . In a preferred embodiment, the heat deflection member  110  may comprise sheet steel of a thickness from about  30  gauge to about  12  gauge. Of course, other metals such as: stainless steel, aluminum, etc., may also be used. As previously stated, the heat deflection member  110  may also comprise ceramic or other similar material. The first and second opposing panels  141 ,  142  may be trapezoidal in shape with the first and second mounting flanges  151 ,  152  attached to the short parallel sides of the first and second opposing panels  141 ,  142 , respectively. To be described below, cutoffs  171 - 174  will provide voids through which combustion products will exit a firebox. The first bend  121  has a length  1  that is slightly shorter than an interior wall-to-wall measurement of a firebox (shown below). The first and second mounting flanges  151 ,  152  need not be continuous along the short parallel sides of the first and second opposing panels  141 ,  142 , respectively, but may be intermittent yet of sufficient length to support the fireplace baffle  100 . The plurality of mounting apertures  160 , when present, may be used to fasten the fireplace baffle  100  to the ceiling of a gas prefabricated fireplace by any suitable method, e.g., bolts, rivets, etc. Alternatively, a baffle of ceramic or other similar material may be attached without fasteners to the firebox ceiling by sliding into appropriately placed channels attached to the ceiling. 
         [0015]    Referring now to  FIG. 2 , illustrated is a sectional view of one embodiment of a fireplace baffle  100  of  FIG. 1  along plane  2 - 2 . In forming the first, second and third bends  121 - 123 , the sheet metal member  110  may literally be bent in a bending brake or metal-forming press, or the bends may be formed by welding, brazing, etc., individual pieces of sheet metal, as appropriate. The first bend  121  may form an obtuse interior angle α ranging from about 91° to about 179°. In one embodiment, the interior angle α is about 160°. The first and second mounting flanges  151 ,  152  may extend from the first and second opposing panels  141 ,  142  at an interior angle β that may vary from about 135° to about 179°. In one embodiment compatible with an interior angle α of 160°, the interior angle β is about 170°. 
         [0016]    Referring now to  FIG. 3 , illustrated is a sectional view of an alternative embodiment of a fireplace baffle  300  along plane  2 - 2  of  FIG. 1 . In this embodiment, the fireplace baffle  300  comprises a sheet-metal, heat deflection member  310  having first and second parallel edges  311 ,  312  and a first bend  321  along a centerline  330  thereof. The sheet-metal, heat deflection member  310  further comprises second through fifth bends  322 - 325 , respectively, parallel the first and second parallel edges  311 ,  312 , and forming: first and second opposing panels  341 ,  342 , first and second panel extensions  361 ,  362 , and first and second parallel mounting flanges  351 ,  352 . As in the embodiment of  FIG. 2 , forming of the first through fifth bends  321 - 325  may be achieved with the sheet metal member  310  literally bent in a bending brake or a metal-forming press, or the bends  321 - 325  may be formed by welding, brazing, etc., individual pieces of sheet metal, as appropriate to the material used. The first bend  321  forms an obtuse interior angle α whose value may range from about 91° and to about 179°. In one preferred embodiment, the interior angle α may be about 160°. The first and second panel extensions  361 ,  362 , respectively, extend from the fourth and fifth bends  324 ,  325 , respectively. The fourth and fifth bends  324 ,  325  form interior angles β′. The first and second mounting flanges  351 ,  352  extend from the first and second opposing panels  341 ,  342  at interior angles β′, that may vary from about 134.5° to about 90.5°, respectively. In this embodiment compatible with an interior angle α of 160°, the interior angles β′ are about 100°. The fireplace baffle  300  has a height h measured from the bottom of the “V” to the height of the first and second mounting flanges  351 ,  352  as shown. 
         [0017]    Referring now to  FIG. 4 , illustrated is a vertical sectional view of a prefabricated gas fireplace  400  along the centerline  130  of  FIG. 1  and constructed in accordance with the present disclosure. The fireplace  400  comprises a firebox  410 , a grate  420 , a gas burner  430 , a fireplace baffle  440 , and a flue  450 . Note that the fireplace baffle  440  is almost equal in length l to the inside width w of the firebox  410 . It should be noted that radiant heat travels in substantially straight lines, while convection heat travels as the gases move about the firebox  410  and up the flue  450 . As the fire burns, thermal currents (convection heat) cause combustion products  460  to rise in the firebox  410 . Upon reaching the fireplace baffle  440 , the combustion products  460  are prevented from immediately entering the flue  450 , but are rather redirected toward first and second ends  441 ,  442  of the fireplace baffle  440 . Without some form of baffle below the flue, much radiant and convective heat would be lost unimpeded up the flue, thus creating higher flue temperatures as will be discussed with reference to  FIG. 6  below. Upon reaching the first and second ends  441 ,  442 , the combustion products  460  flow around the cutoffs  171 - 174  (See also  FIG. 1 ) and back toward a center of the fireplace baffle  440 , then upward and out the flue  450 . While combustion products are thus effectively exhausted, radiant heat  470  created by the gas burner  430  is emitted in straight lines in all directions from the flame  480 . Because of the angled nature of the first and second opposing panels  141 ,  142 , or  341 ,  342 , respectively, the radiant heat  470  is redirected upon impinging the first and second opposing panels  141 ,  142  or  341 ,  342 , toward the glass front of the fireplace  400  or desired areas within the firebox  410 , and ultimately toward the space proximate the outside face of the fireplace  400 , thus making the fireplace  400  more efficient in directing heat where it is most desired. The degree to which radiant heat is redirected can be controlled by the choice of the angle α (See  FIG. 3 ) of the fireplace baffle  440 . Variation in this angle can be controlled by adjusting the depth d of the fireplace baffle  440  (See  FIG. 3 ). It should be noted that adjusting the depth d of the fireplace baffle  440  will also affect the esthetics of the fireplace  400  as a greater depth d will be more visible through the glass doors than a shallow depth d. 
         [0018]    Referring now to  FIG. 5A and 5B , illustrated are front elevation and vertical sectional views, respectively, of a representative prefabricated fireplace constructed in accordance with the present disclosure. For a three-hour test, the test fireplace  400  was installed in an enclosure similar to how the fireplace would be installed in a home. In this instance, the fireplace  400  was installed in an enclosure that included drywall above the fireplace doors, proximate the left and right firebox walls, and extending forward from the right firebox wall to simulate installing the fireplace in a corner of a room. Multiple thermocouples were distributed over each area or panel of interest. The panels or areas were: the flue  450 , right side wall  501 , front floor  502 , front drywall  503 , front upper panel  504 , rear upper panel  505 , firebox ceiling  506 , rear drywall  507 , left side wall  508 , outer side wall  509 , and rear floor  510 . The right side wall  501 , front drywall  503 , rear drywall  507 , left side wall  508 , and outer side wall  509  are parts of the enclosure surrounding the test fireplace  400  replicating how it might be installed in a room. The outer side wall  509  is an extension of the test enclosure and simulates a wall adjacent to the fireplace  400 . The front floor  502  and rear floor  510  are the areas of the facility floor in front of and behind the test fireplace  400 , respectively. The front upper panel  504 , rear upper panel  505  and firebox ceiling  506  are parts of the fireplace  400 . Four different baffle configurations of the fireplace were tested. The four configurations of the fireplace are: (a) no baffle with open flue, (b) flat (conventional) baffle, (c) 1.5″ baffle and (d) 2.25″ baffle. The definition of 1.5″ and 2.25″ baffle refers to the depth d of the baffle with the configuration as shown in  FIG. 3 . 
         [0019]    Referring now to  FIG. 6  with continuing reference to  FIGS. 5A and 5B , illustrated is a chart of average temperatures of the cabinet, flue and surroundings collected with thermocouples at the above listed locations within and without one representative prefabricated fireplace with each of the four baffle configurations. Test results reflect average temperatures measured with a plurality of thermocouples distributed over a given panel or area as noted above for each of the four different configurations of the fireplace  400 . The temperatures were recorded and averaged after three hours of continuous fireplace operation. 
         [0020]    Commencing on the left side of the chart, it can be clearly seen from the first column group  610  that the average flue temperature drops for configurations b, c and d above (relative to the no-baffle state, configuration a), due to the baffling holding heat in the firebox area and forcing more radiant heat toward the glass front and the surrounding room. The “V-baffling” (configurations c and d) demonstrate that more radiant heat is directed outwardly toward the glass front and the front floor  502 , i.e., the third column group  630 . The first column group  610  further demonstrates that the deeper V-baffle (configuration d) allowed more heat to escape into the flue  450  (increased flue temp vs. configuration c); however, overall, the flue temperature was still reduced, i.e., about at least 130° F., and comparable to the conventional baffle (configuration b). Nonetheless, an increased temperature in the front floor area, the third column group  630 , was demonstrated; thereby indicating better heat reflection toward the desired area, i.e., the glass front and proximate area. The third column group  630  shows average temperatures recorded at the front floor  502  and indicate an increase in the recorded temperatures for all baffle configurations, b through d, relative to the un-baffled configuration a, from increased heat reflected downwardly and outwardly through the desired area, i.e., the glass front. 
         [0021]    The fourth column group  640  shows a slight decrease in the average temperature of the front drywall  503  above the fireplace  400  front as might be expected from reflected radiant heat being directed more toward the floor than toward the upper front of the fireplace  400 . Yet, the results show a slight decrease in average temperature at the front drywall of the “V” baffled configurations c and d relative to the conventional flat baffle. 
         [0022]    The fifth column group  650  shows a slight increase in average temperature at the front upper panel  504 , relative to the conventional flat baffle, likely indicative of increased convective heat caused by the extra radiant heat exiting from the glass front as well as convective currents increased by the increased temperatures of the front floor  502  as shown in the third column group  630 . 
         [0023]    The second column group  620  (right side wall  501 ) and the ninth column group  690  (left side wall  508 ) are more indicative of, and relative to, a reduction in overall enclosure temperatures as they are not as exposed to radiant heat as the other surfaces, and more heat energy is being directed toward and through the glass front than the no-baffle configuration a. 
         [0024]    The sixth column group  660  (rear upper panel  505 ) and the eleventh column group  695  (rear floor  510 ) do not show much variation from the conventional baffle, configuration b, as the rear glass in this test configuration was both double pane and tinted. 
         [0025]    The seventh column group  670  (firebox ceiling  506 ) shows relatively constant ceiling temperature in all configurations, while the eighth column group  680  (rear drywall  507 ) shows decreases in average temperatures above the rear glass doors as might be expected because of the double pane and tinted glass of the rear doors. 
         [0026]    The tenth column group  693  (outer side wall  509 ) shows an increase in temperatures on the wall adjacent to the right side of the fireplace  400 . This would be indicative of the increased heat emanating from the glass doors of the fireplace  400  thereby heating the proximate surfaces and the surrounding air. 
         [0027]    Thus, a new baffle configuration for gas prefabricated fireplaces has been described that dramatically reduces flue temperatures while reflecting more radiant heat toward the desired surface, i.e., the glass front and fireplace surroundings without significant increase in overall firebox temperatures as compared to conventional baffles. A reduction of flue temperature of about at least 130° F. from the no-baffle configuration and yet a reduction of between about 8° F. to about 35° F. from the conventional baffle was seen while other areas, e.g., the front floor increased 2° F. to 3° F. over the conventional baffle yet as much as 5° F. over the no-baffle configuration, indicating improved direction of radiant heat toward the front glass over conventional designs. As such, the fireplace implementing the baffle as covered by the embodiments herein allow a higher BTU per hour or higher temperature operation of the fireplace, thereby providing more heat to a room. While the above discussion has been directed toward a baffle for a gas fireplace, other applications such as stoves, inserts, etc., may also benefit from the described apparatus. It should be noted that the data displayed is for the fireplace configuration as described and exact results using other “V” baffle configurations may vary. 
         [0028]    For the purposes of this discussion, use of the terms “providing” and “forming,” etc., includes: manufacture, subcontracting, purchase, etc. Those skilled in the art to which this application relates will appreciate that other and further additions, deletions, substitutions and modifications may be made to the described embodiments.