Patent Publication Number: US-8528540-B2

Title: Fire grate for enhanced combustion with vertical and horizontal expansion sleeves

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 12/620,453, filed Nov. 17, 2009 now abandoned, which is a continuation-in-part application of U.S. patent application Ser. No. 12/501,869, filed Jul. 13, 2009 now abandoned, the entire contents of which is expressly incorporated herein by reference. 
    
    
     STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENT 
     Not Applicable 
     BACKGROUND 
     The improved fire grate for enhanced combustion relates to an apparatus for improving efficiency of a fireplace in relation to reduction in harmful emissions and/or heating a room. 
     A fireplace is a structure to contain a fire for heating. The fire is contained within a firebox which defines a combustion chamber. A chimney or other flue directs combustion gas to the environment. Studies have shown that fireplaces produce a significant amount of emissions (e.g., particulate, carbon monoxide, volatile organic compounds, etc.) that is harmful to humans and the environment. These harmful emissions rise up with the combustion gas and escape through the chimney to the environment. 
     There are three time honored principles to good combustion. They relate to time, temperature and turbulence. Time is residence time or the amount of time combustion gas remains within the combustion chamber. The longer the combustion gas stays within the combustion chamber, the more complete the combustion process and harmful emissions are reduced. Temperature relates to the temperature within the combustion chamber. The higher the temperature, the better and efficient the burn. As such, there are less harmful emissions. Turbulence relates to the amount of air mixing occurring within the combustion chamber. During operation of the fireplace, the biomass/fuel being burned consumes oxygen in the surrounding area. Fresh air is introduced into the combustion chamber through the fireplace opening. Stratified columns of fresh oxygen rich air rise up in the combustion chamber along side the starved combustion gases. The harmful emissions contained within the oxygen starved combustion gases do not come into contact with the oxygen rich air. Turbulence promotes mixing of the stratified layers or columns of fresh oxygen rich air with the oxygen starved air to encourage a cleaner burn and reduce harmful emissions. 
     The biomass/fuel being burned produces harmful emissions because the residence time of the combustion gas in the combustion chamber may be too short to allow the biomass/fuel to completely combust. Additionally, the biomass/fuel being burned may not completely combust because the temperature within the combustion chamber may be too low. Moreover, during the combustion process of the biomass/fuel, oxygen in the surrounding area of the biomass/fuel is consumed thereby producing oxygen starved combustion gases. These oxygen starved combustion gases rise, containing the harmful emissions, up through the combustion chamber into the chimney and out into the environment in a vertical column. 
     BRIEF SUMMARY 
     The improved fire grate addresses the needs of reducing harmful emissions discussed above, discussed below and those that are known in the art. 
     The improved fire grate may be disposed within a combustion chamber of a conventional fireplace. The conventional fireplace defines a single combustion zone. The improved fire grate creates two combustion zones, a primary and secondary combustion zone. This primary combustion zone is at the lower portion of the combustion chamber. The primary combustion zone is the part of the combustion chamber in which the biomass/fuel is being burned. During combustion or burning of biomass/fuel, combustion gases will rise up due to convection (i.e., rising hot air). Any harmful emissions (e.g., particulate matter, carbon monoxide, etc.) may float or be contained within that combustion gas stream. 
     The improved fire grate comprises a hollow tubular conduit that routes fresh oxygen rich air into the combustion chamber and releases the fresh oxygen rich air in a secondary combustion zone of the combustion process. The secondary combustion zone is above the primary combustion zone within the combustion chamber. The hollow tubular conduit may bring fresh oxygen rich air from the room through the fireplace opening or from any reliable oxygen rich air source. The hollow tubular conduit may be routed to the back of the fireplace up and over the biomass/fuel. The hollow tubular conduit may have a plurality of air apertures for releasing the fresh oxygen rich air into the secondary combustion zone where it generally has less oxygen compared to the primary combustion zone. 
     The hollow tubular conduit may define an upper frame comprised of a plurality of hollow tubes. These tubes may be configured to cover a substantial area of the combustion chamber over the biomass/fuel. By way of example and not limitation, first and second tubes may be generally parallel and be placed at the front and rear of the combustion chamber. Side tubes may be in fluid communication with the front and rear tubes. One or more of the first tube, second tube and side tubes may have air apertures which permit the air brought in from the fresh oxygen rich air source to be introduced into the secondary combustion zone of the combustion chamber. The fresh oxygen rich air is introduced into the secondary combustion zone since the secondary combustion zone will typically have less air or oxygen. The air or oxygen resident within the fireplace was partially consumed during the burning process in the primary combustion zone. The combustion gas that rises above the fuel source into the secondary combustion zone is oxygen starved. The fresh oxygen rich air introduced into the secondary combustion zone via the hollow tubular conduit provides an additional source of fresh oxygen rich air to assist in the completion of the burning process for the incompletely combusted harmful emissions. As the fresh oxygen rich air is routed from the fresh oxygen rich air source to the upper frame, the fresh oxygen rich air may be preheated prior to introduction in the secondary combustion zone to maintain the temperature at the secondary combustion zone. This is accomplished by routing the hollow tubular conduit from the fireplace opening, back to the rear of the combustion chamber, and up to the secondary combustion zone. The hollow tubular conduit is exposed to the heat in the combustion chamber. 
     In addition to supplying fresh oxygen to the secondary combustion zone of the combustion chamber, a baffle plate may be disposed over the biomass/fuel to be burned. The baffle plate interrupts the flame path rising up from the biomass/fuel being burnt in the sense of velocity, direction and turbulence. The interruption of the flame path encourages larger incompletely burned harmful particulate to fall out of the combustion gas stream and may be reentrained in the combustion gas stream at an earlier point and rise back up toward the baffle plate. This allows the harmful particulate to stay within the flame path for a longer period of time (i.e., longer residence time) and promotes more complete combustion thereby reducing harmful emissions. There are generally less harmful particulate, the more time the particulate stays within the combustion chamber. Also, a more complete combustion is promoted thereby reducing harmful emissions. The baffle plate may be fabricated from a refractory material or another material having good insulation characteristics. As such, the baffle plate increases the temperature at the secondary combustion zone as well as the primary combustion zone to promote complete burning of the harmful particulate matter. It is also contemplated that the baffle plate may have a lower surface formed with a plurality of channels or other groove shapes to interrupt the flow of gas flowing up from the fuel source to the chimney. The channels or grooves formed in the lower surface of the baffle plate may be configured to route the combustion gas stream toward the sides of the baffle plate. When the gas stream from the sides of the baffle plate and the gas stream from the front of the baffle plate recombines above the baffle plate, turbulence may occur which promotes mixing of oxygen rich air with the oxygen starved air. 
     The baffle plate may also be tilted in the forward direction. Provided that the baffle plate also has good emissivity characteristics, the forward tilt may redirect heat from the burning biomass/fuel into the room to be heated. This may also allow the improved fire grate with enhanced combustion to be utilized in a zero clearance fireplace as well as a masonry fireplace. The baffle plate may optionally be disposed slightly forward of the fuel source to allow flames from the fuel source to rise up behind the baffle plate. This further splits up the gas stream such that the recombined gas streams above the baffle plate may be more turbulent and promote mixing of oxygen starved and oxygen rich air. 
     Optionally, a log lighter may be disposed in the primary combustion zone and below the biomass/fuel to be burned. This log lighter aids in rapid ignition of the biomass/fuel. The log lighter may be turned off after the biomass/fuel starts its burning process. However, it is also contemplated that the log lighter may be left on to promote efficient burning of the fuel source. Other log lighters may be disposed at other areas within the combustion chamber. By way of example and not limitation, one or more log lighters may be disposed in the secondary combustion zone of the combustion chamber. As discussed above, the baffle plate redirects the combusted gas stream having harmful emissions therein. The log lighter disposed in the secondary combustion zone may increase temperature in the secondary combustion zone. The increased temperature aids in completing the burning process of the biomass/fuel and reducing harmful emissions. 
     The improved fire grate provides for a unique and efficient supplement to any existing fireplace. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features and advantages of the various embodiments disclosed herein will be better understood with respect to the following description and drawings, in which like numbers refer to like parts throughout, and in which: 
         FIG. 1  is a perspective view of an improved fire grate; 
         FIG. 2  is a cross sectional view of the improved fire grate shown in  FIG. 1 ; 
         FIG. 3  is an exploded perspective view of the improved fire grate shown in  FIG. 1 ; 
         FIG. 4  is an enlarged view of a log lighter shown in  FIG. 1  having aligned holes; 
         FIG. 4A  is cross sectional view of an elongate tube of the log lighter shown in  FIG. 4 ; 
         FIG. 5  is an alternate embodiment of the log lighter having staggered holes; 
         FIG. 6  is a schematic of an ignition system and logic control system; 
         FIG. 7  is a front view of a second embodiment of the improved fire grate; 
         FIG. 8  is a cross sectional view of the improved fire grate shown in  FIG. 7 ; 
         FIG. 9  is a perspective view of two fire sources connected to a first embodiment of a mixing chamber; 
         FIG. 10  is a top view of a second embodiment of a mixing chamber; 
         FIG. 11  is a cross sectional view of the second embodiment of the mixing chamber shown in  FIG. 10 ; 
         FIG. 12  is a cross sectional view of the second embodiment of the mixing chamber shown in  FIG. 11 ; 
         FIG. 13  is a cross sectional view of the second embodiment of the mixing chamber shown in  FIG. 12 ; and 
         FIG. 14  is an alternate embodiment of an air chamber shown in  FIG. 13 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawings, an improved fire grate  10  for enhanced combustion is shown. The improved fire grate  10  may be disposed within a combustion chamber  12  (see  FIG. 2 ) of a fireplace  14 . The improved fire grate  10  introduces oxygen rich air to a secondary combustion zone  50  of the combustion chamber  12 , retains heat within the combustion chamber  12  to increase a temperature of the combustion chamber  12 , encourages mixing of oxygen rich air with oxygen starved combustion gas stream, and increases residence time of the combustion gas stream for the purpose of reducing harmful emissions during fireplace use. 
     Referring now to  FIG. 3 , an exploded view of the improved fire grate  10  is shown. The improved fire grate  10  may be fabricated from a tubular design made from a cost effective material (e.g., steel, aluminum ceramics, etc.) of appropriate temperature and chemical resistance characteristic. The fire grate  10  may have an adjustable width  22 . To this end, the improved fire grate  10  may have a first side  24  and a second side  26 . The first side  24  may have a plurality of tubes  28   a - d  which are slidably insertable into tubes  30   a - d  of the second side  26  of the improved fire grate  10 . The tubes  28   a - d  telescope into and out of the tubes  30   a - d . More particularly, the tubes  28   a, b, c, d  may be insertable into tubes  30   a, b, c, d , respectively. The tubes  28   a - d  may have a frictional fit with tubes  30   a - d  such that once the tubes  28   a - d  are inserted into tubes  30   a - d , they  28   a - d  and  30   a - d  are set and do not need further adjustment to fit the combustion chamber  12 . The installer adjusts the width  22  such that the first and second sides  24 ,  26  fill a substantial area of the combustion chamber  12 . Alternatively, the first and second sets of tubes  28   a - d  and  30   a - d  may be fixed in relation to each other through a pin, setscrew or other means known in the art. 
     Additionally, the improved fire grate  10  may have an adjustable height. To this end, vertical tubes  38   a, b  may be telescoping and set to a height to fit within the combustion chamber  12 . The telescoping length of the tubes  38   a, b  may be set by friction fit, pin, set screw or other means known in the art. 
     The improved fire grate  10  may have an upper frame  32  and a lower frame  34 . The upper frame  32  may comprise the tubes  28   a, b  and  30   a, b  but also hollow tubes  28   e  and  30   e  which may be splayed to fit the general configuration of combustion chambers  12  of modern fireplaces  14  and/or to provide better cover of the burning biomass/fuel  20 . One or more of the tubes  28   a, b, e  and  30   a, b, e  may have a plurality of air outlet holes  36  which introduces fresh oxygen rich air above the biomass/fuel  20 , as shown in  FIG. 2 . The air outlet holes  36  may be formed to direct air down toward the biomass/fuel  20 , and/or out toward the outer periphery of the upper frame  32  and/or inward toward the inner periphery of the upper frame  32 . Fresh oxygen rich air  44  may be supplied to the upper frame  32  and out of the air outlet holes  36  via tubular supports  38   a, b  (see  FIG. 3 ) and an airflow path through the tubes  40   a  and  42   a  (see  FIG. 3 ) of the lower frame  34 . 
     During operation, fresh air or oxygen  44  may enter through the tubes  40   a ,  42   a  of the lower frame  34  through induction (convection), forced airflow (e.g., blower), or other means known in the art. If via induction, the fire in the combustion chamber  12  heats up the tubes  38   a ,  38   b ,  40   a ,  42   a , and the upper frame  32 . Since hot air rises, the heat air rises through the tubes  38   a ,  38   b ,  40   a ,  42   a , and the upper frame  32  and out of the air outlet holes  36 . The fresh oxygen rich air  44  may be taken from the bottom front of the fireplace  14  or another fresh air source. The fresh oxygen rich air  44  flows through the tubes  40   a ,  42   a  and up through the tubular supports  38   a, b . The fresh oxygen rich air  44  may be distributed throughout the tubular structure of the upper frame  32  and exit out of the air outlet holes  36  formed in one or more of the tubes  28   a, b, e  and  30   a, b, e . As the fresh oxygen rich air  44  flows through the tubular structure  38 ,  40   a ,  42   a , the fresh oxygen rich air  44  is preheated prior to being introduced into a secondary combustion zone  48  of the combustion chamber  12  (see  FIG. 2 ) to maintain the higher temperature within the combustion chamber. 
     Initially, the biomass/fuel  20  is burned in a primary combustion zone  50  (see  FIG. 2 ), namely, at the biomass/fuel  20 . As the biomass/fuel  20  burns, the combustion process consumes both the biomass/fuel  20  as well as the surrounding oxygen  52 . As the biomass/fuel  20  burns, some of the biomass/fuel  20  does not completely burn and rises as a of the combustion gas stream which includes harmful emissions such as particulate matter  46 . Since hot air rises, the particulate matter  46  rises along with the rising combustion gas stream into the secondary combustion zone  48  where the particulate  46  comes into contact with fresh oxygen rich air  44  introduced into the secondary combustion zone  48  of the burning process via the upper frame  32 . The introduction of fresh oxygen rich air  44  at the secondary combustion zone  48  assists to further the burning process to mitigate release of harmful emissions into the environment. Beneficially, oxygen rich air exits out of the holes  36  (see  FIG. 3 ) in a location (i.e., secondary combustion zone of the combustion chamber) which is oxygen starved to complete the combustion and reduce harmful emissions. As discussed herein, the combustion gas stream may contain columns or stratified columns of oxygen starved air as well as oxygen rich air. The location of the holes  36  may be placed at a location where oxygen starved air is expected. 
     Referring back to  FIG. 1 , a baffle plate  54  having good insulating characteristics may be disposed about the inner periphery of the upper frame  32 . By way of example and not limitation, the baffle plate  54  may be fabricated from a refractory material. As shown in  FIG. 3 , the inner periphery of the upper frame  32  may have a plurality of tabs  56  to hold up the baffle plate  54  within the inner periphery of the upper frame  32 . In the event that the improved fire grate  10  has an adjustable width  22 , the improved fire grate  10  may be provided with a plurality of baffle plate slabs  58   a - e  such that the appropriate slabs  58   a - e  may be fitted to the width  22  of the improved fire grate  10 . The slabs  58   a - e  are shown in  FIG. 3 . The baffle plate  54  may be tilted in the forward direction, as shown in  FIG. 2 . This is to aid in reflecting heat out through the fireplace opening  16 . More particularly, the lower surface  60  of the baffle plate  54  may face the fireplace opening  16  to accomplish the reflection of heat through the fireplace opening  16 . The baffle plate  54 , as discussed above, may have good insulating characteristics. As such, the baffle plate  54  may also increase the temperature in the secondary combustion zone  48  of the combustion chamber  12  to further encourage the combustion process and reduce harmful emissions. The increased heat in the secondary combustion zone  48  caused by the baffle plate  54  aids in the burning process of the harmful emissions in the secondary combustion zone  48  as well as in the primary combustion zone  50  to reduce harmful emissions into the atmosphere. 
     It is also contemplated that additional optional baffle plates  55   a, b, c  may be disposed at other areas of the improved fire grate  10 , as shown in  FIG. 1 . By way of example and not limitation, a baffle plate  55   a  may be attached to the rear side of the improved fire grate  10  at tubes  38   a, b . The baffle plate  54  attached to these tubes  38   a, b  may extend from the lower frame  34  to the upper frame  32  to increase a temperature within the primary combustion zone  50  and the secondary combustion zone  48 . Additional baffle plates  55   b, c  may be lined on the sides of the improved fire grate  10  that extends from tubes  40   a ,  28   e  and  42   a ,  30   e . These additional baffle plates  55   a, b, c  as well as baffle plate  54  also aid in maintaining or increasing the temperature at the primary combustion zone  50  and the secondary combustion zone  48  and promote more efficient combustion of the biomass/fuel  20 . The baffle plates  55   a, b, c  may be attached to the fire grate  10  via adhesives, nut and bolts and/or other attachment methods known in the art. 
     The baffle plate  54  increases gas residence time of the combustion gas in the primary and secondary combustion zones  50 ,  48  thereby encouraging or promoting more complete combustion of the biomass/fuel  20  and reduction of harmful particulate. Additionally, the flame produced by the fuel source  20  may impinge the baffle plate  54 . As a result, larger particulate  46  may drop out of the combustion gas stream back toward the primary combustion zone  50  and reenter the combustion gas stream. The residence time of the larger particulate  46  in the combustion gas stream is increased which provides additional time for the larger particulate  46  to complete its combustion process. 
     The baffle plate  54  also prevents the combustion gas from going straight up through the chimney but rather provides a barrier to provide a circuitous flame path around the baffle plate  54 . Since the natural vertical flame path is interrupted, mixing of oxygen rich air with oxygen starved air is encouraged. Additionally, since the length of the flame path is now increased, residence time of the combustion gas in the primary and secondary combustion zones  50 ,  48  is increased to promote more complete combustion and reduction of harmful emissions. Additionally, since the baffle plate  54  is tilted forward, the gas as well as the particulate  46  following such combusted gas stream is re-directed to the front of the improved fire grate  10  at the upper frame  32  where oxygen  44  is introduced to encourage more complete combustion and to reduce harmful emissions (e.g., particulate matter, carbon monoxide, etc.). It is contemplated that the baffle plate  54  may optionally be disposed slightly forward of the fuel source  20  such that a portion of the flames and combustion gas proceeds past the back of the baffle plate  54 . Please note that the fresh oxygen rich air  44  may also be supplied to the back side via tubes  28   a ,  30   a  to aid in combustion of the such combustion gas and particulate. 
     Referring back to  FIG. 2 , the lower surface  60  of the baffle plate  54  may have channels  65  that extend horizontally from left to right. These channels may have a semicircular concave configuration as shown in  FIG. 2  but other configurations (e.g., vertical, diagonal, etc.) are also contemplated. The channels  65  promote the gas to flow toward the perimeter (e.g., sides) of the improved fire grate  10 . The combustion gas may be divided into two or more flame paths, namely, a portion of the combustion gas may proceed forward and around the front edge of the baffle plate  54 . The combustion gas may flow outward toward the sides of the baffle plate  54  and around the baffle plate  54  to join up with the combustion gas that flowed past the front edge of the baffle plate  54 . The separation and recombination of these flame paths encourage mixing of air above the baffle plate  54 . A portion of the combustion gas stream may pass the rear edge of the baffle plate. This increases mixing action, increases particulate drop out and residence gas time within the primary and secondary combustion zones  50 ,  48 . Alternatively, the channels  65  may extend vertically to route combustion gas to the front side of the upper frame  32 . Additionally, through holes  67  may be formed through the baffle plate  54  that extend from the lower surface  60  and/or channels  65  to the upper surface  69  for the purposes of encouraging particulate removal and mixing of oxygen rich air with the oxygen starved air. 
     Referring now back to  FIGS. 1 and 2 , one or more fire sources  62  may be disposed at select locations within the secondary combustion zone  48 . The fire sources  62  may be an elongate tube  64  with a plurality of holes  66  that may be directed outward. These elongate tubes  64  with holes  66  are supplied with combustible gas such as propane, natural gas, etc. via a system of tubes from a gas source. By way of example and not limitation, the fire sources  62  may be a log lighter sold under the trademark BLUE FLAME. The fire source  62   a  is shown in  FIGS. 1 and 2 . 
     Referring now to  FIG. 9 , two fire sources  62  may be disposed below the fire grate  10  (not shown for purposes of clarity). Each of the fire sources  62  may be in fluidic communication with one mixing chamber  79 . Each of the mixing chambers  79  may be in fluidic communication with a manifold  92 . The manifold  92  may have a flammable gas inlet  94  for receiving flammable gas via a conduit  96  connected to a flammable gas source  98 . The fire sources  62  may have elongate tubes  64  with either aligned or straight holes  66  or staggered holes  66  as discussed herein. Each of the mixing chambers  79  may have an air conduit  93  that has an inlet  95  that is either directed to the side or downward. The inlet  95  receives air and introduces air into the mixing chamber. The mixing chambers  79  are in fluid communication with the manifold  92  by way of an orifice  97 . The manifold  92  introduces flammable gas into the mixing chamber  79 . Accordingly, the mixing chambers  79  mix air with flammable gas and introduce the mixed flammable gas/air into the elongate tubes  64 . At the mixing chamber, the mixture of flammable gas and air is combustible. The air conduits  93  prevent embers or an ignition source from falling into the mixing chamber  79  and inadvertently igniting the flammable mixture in the mixing chamber  79  prior to entrance into the elongate tubes  64 . As discussed above, the fire sources  62  are disposed below the fire grate  10 . As such, the mixing chambers  79  are disposed closely adjacent to the biomass/fuel  20  being burned. Embers from the biomass/fuel source  20  may fall into the mixing chambers  79  without the air conduits  93 . The air conduits  93  may have an elongate nature and the inlets  95  may be disposed away (e.g., distanced away, oriented sideways, oriented downward, etc.) from the biomass/fuel source  20 . Falling embers hit the air conduits  93  and do not enter the mixing chambers  79 . 
     Referring still to  FIG. 9 , the fire sources  62  may be disposed in an optimal position with respect to the fire grate  10 . In particular, the flammable gas source  98  may have a half inch connection. A reducer  99  (e.g., ½″ to as small as ¼″) may be connected to the flammable gas source  98 . The reduced sized conduit  96  (e.g., flex tubing, copper tubing, etc.) may be bent or shaped and connected to the flammable gas inlet  94  of the manifold  92 . Accordingly, after the fire sources  62  are optimally placed with respect to the fire grate  10 , the conduit  96  allows the fire sources  62  to remain in the optimal position, regardless of the position of the flammable gas source  98  on a vertical wall or a ground  90 . Regardless of the left to right position or front to back position of the fire sources  62  as well as the vertical position of the flammable gas source  98 , the bendable conduit  96  allows the fire sources  62  to be placed optimally with respect to the fire grate  10 . 
     It is also contemplated that one mixing chamber  79  may be in fluid communication and control combustible gas flow to two or more fire sources  62 . 
     Flammable gas (e.g., propane, natural gas, etc.) may be routed to the fire sources  62   a, b  via pipes  63  (see  FIG. 1 ). During operation of the fireplace  14 , the user may ignite the gas flowing out of the holes  66  of the elongate tube  64 . The rapid ignition and additional heat increases the temperature in the primary combustion zone  50  to reduce harmful emissions and support additional combustion of flue gases. Additional fire sources  62  may also be disposed within the secondary combustion zone  48  such as at the rear (see fire source  62   b  in  FIG. 1 ) of the combustion chamber  12  as well as the sides (not shown) of the combustion chamber  12 . The BTU rating, location and flame hole distribution is to be determined based on test results. The fire sources  62  in the secondary combustion zone are optional. 
     The lower frame  34  may have a similar construction as that compared to the upper frame  32 . The lower frame  34  may be fabricated from telescoping tubes  28   c  and  30   c  as well as telescoping tubes  28   d  and  30   d . These respective tubes may have a frictional fit to fix the width  22  of the improved fire grate  10 . It is contemplated that the tubes  28   c, d  and tubes  30   c, d  may or may not be in fluid communication with tubes  38   a ,  40   a  or tubes  38   b ,  42   a . Fresh oxygen rich air  44  may flow through tubes  40   a ,  42   a ,  38   a  and  38   b  up to the upper frame  32 . A crossbar  68  may be disposed over the tubes  28   c ,  30   c  and  28   d ,  30   d . The biomass/fuel  20  may be laid across tube  40   a , crossbar  68  and tube  42   a  to raise the biomass/fuel  20  above the ground. The tubular supports  38   a, b  along with retaining pipes  70   a, b  retain the biomass/fuel  20  on the lower frame  34 . Two legs  72   a, b  may be attached (e.g., tack welded) to tubes  40   a ,  42   a . Baffle plate  74   a, b  may be attached (e.g., tack welded or other means) to the tubes  28   d ,  30   d  to provide leg support at the front of the improved fire grate  10 . The baffle plate  74   a, b  may also be fabricated from a refractory material or other material having good insulation characteristics. The baffle plates  74   a, b  may overlap one another and provide a semi-enclosed space behind the baffle plates  74   a, b  during operation, as shown in  FIG. 1 . The baffle plates  74   a, b  directs airflow coming through the fireplace opening  16  up and into the primary combustion zone  50  of the combustion chamber. 
     A fire source  62   c  may also optionally be disposed below the lower frame  34 , as shown in  FIG. 2 . The fire source  62   c  may be an elongate tube  64  with a plurality of holes  66 , as shown in  FIGS. 4-5 . The elongate tubes  64  may have a hollow configuration to allow gaseous fuel (e.g., propane, natural gas, etc.) to flow through the elongate tube  64  and out of the holes  66 . This fire source  62   c  provides for rapid initial ignition of the biomass/fuel  20  and may be left on to supplement the combustion process for the entire time the biomass/fuel  20  is being burned to maintain a more efficient burning state. The additional fire source  62  assists in bringing new unburnt biomass/fuel (e.g., wood logs) to an efficient burning state. The holes  66  may be aligned (i.e., straight) to each other along a longitudinal length of the elongate tubes  64 . These holes  66  may be oriented vertically upwards. Alternatively, the holes  66  may be staggered as shown in  FIG. 5  along the length of the elongate tubes  64 . The holes  66  may also be at a ninety (90) degree angle with respect to each other as shown in  FIG. 4A  and be directed in the generally upward direction as shown in  FIG. 2 . The fire source  62   c  may be disposed centrally below the lower frame  34  as shown in  FIG. 2 . It is also it is contemplated that two (2) fire sources  62   d, e  may be disposed below the lower frame  34  evenly distributed there below. The fire sources  62   a, b  disposed in the second stage  48  of the combustion chamber  12  may have the same configuration (e.g., straight, outwardly angled) as the fire sources  62   c - e . The additional fire sources  62   c - e  and the staggered and outwardly angled holes  66  (see  FIG. 5 ) of the fire sources  62   c - e  promote even heat distribution under the biomass/fuel  20  being burned. 
     It is also contemplated that an ash pan  76  may be disposed below the lower frame  34  and the fire source  62   c, d, e . The ash pan  76  aids in the cleanup of the fireplace  14  after use. 
     Referring now to  FIG. 6 , an ignition system/logic control system  78  is contemplated. The log lighters  62   a, b, c, d, e  disclosed herein may be in fluid communication with a manifold  80  that receives flammable gas (e.g., propane, natural gas, etc.) from a flammable gas source  82 . Based on the configuration of the improved fire grate  10  and the placement and number of heat sources  62   a - e  incorporated into the system, an ignition and logic control unit  84  which may be electro-mechanically connected to the manifold  80  opens and closes various valves to supply flammable gas to one or more of the log lighters  62   a - e . Various sensors  86  (e.g., carbon monoxide sensor, temperature sensor, oxygen sensor, etc.) may be disposed within the combustion chamber  12 , the room to be heated, the chimney, or at other various locations within or adjacent the fireplace  14  to measure the efficiency of the fireplace  14 . Based on the sensed information, such sensed information may be transmitted to ignition and logic control unit  84  such that the appropriate amount of flammable gas is being supplied to one or more of the log lighters  62   a - e . To light the log lighters  62   a - e , an ignition switch  88  may be disposed adjacent the log lighter to provide a spark or initial pilot flame to the log lighter. Based on which log lighters  62   a - e  is to be ignited, the ignition and logic control unit  84  may send a signal to the ignition switch  88  to either start and leave on one or more of the log lighter  62   a - e . To turn off one or more of the log lighters  62   a - e , the ignition and logic control unit  84  may shut off supply of flammable gas to that particular log lighter  62   a - e.    
     Still referring to  FIG. 6 , the heat sources  62   a - e  may be controlled by a manual push button switch  91 . The user will place biomass/fuel source  20  on the fire grate  10 . At this time, the user may push the push button switch  91  to activate the ignition and logic control unit  84 . At this time, gas is provided to the pilot and the ignition switch  88  supplies a spark to supply pilot flame. The pilot flame is located at or near the path of flammable gas flow through the holes  66  in the elongate tubes  64 . A thermocouple may recognize that the pilot flame is currently lit. Once the pilot flame is lit and recognized, the manifold  92  may feed flammable gas into one or more of the heat sources  62   a - e  as determined by the logic control unit  84 . At this time, the pilot flame lights the gas flowing through the holes  66  of the elongate tubes  64  of each of the heat sources  62   a - e . Once the flame of the heat sources  62   a - e  is recognized by way of a thermocouple or other device, gas to the pilot flame may be terminated. Preferably, the ignition and logic control unit  84  supplies flammable gas to the heat sources  62   a - e  by way of the manifold  80  for a set period of time (e.g., ten (10) minutes) to allow the biomass/fuel source  20  to burn at an efficient state. After this set period of time, the manifold  80  shuts off gas flow to one or more of the fire sources  62   a - e  as desired. By way of example and not limitation, the heat sources  62  disposed below the fire grate  10  are turned off after the set period of time. However, the other heat sources  62  disposed at other areas within the fireplace  14  may remain on to promote efficient burn as discussed herein. The logic control unit  84  may also shutoff gas flow to the heat sources  62   a - e  if a flame is not recognized by way of a thermocouple or other device. 
     The switch  91  may also have two different settings, namely, a manual setting which the operator must push or activate as discussed above and an automatic setting. In the automatic setting, the above procedure will occur when one or more of the sensor  86  (e.g., temperature) indicates that a condition exists in the fireplace that would benefit from the temporary or long term burning of one or more of the fire sources. By way of example and not limitation, a temperature sensor  86  may indicate a low temperature reading within the fireplace  14 . The user may place a biomass/fuel source on the fire grate  10 . A sensor  86  may detect the presence of the biomass/fuel source and temporarily turn on one or more of the fire sources  62  disposed below the fire grate  10  and/or the other fire sources  62  disposed at other locations. Conversely, in the automatic setting, the logic control unit  84  may shut off gas flow to one or more of the fire sources  62  when one or more of the sensors  86  indicate efficient burning of the biomass/fuel source  20 . 
     Referring now to  FIGS. 7 and 8 , a second embodiment of the improved fire grate  10   a  is shown. The improved fire grate  10   a  may be vertically and horizontally expanded or contracted so as to be sized and configured to fit within one of a plurality of different fireplace sizes. It is contemplated that the improved fire grates  10 ,  10   a  may be fabricated and provided to the public in a small range size, medium range size and a large range size. The height and width of the improved fire grate  10 ,  10   a  may be adjusted to fit within the combustion chamber  12  of the fireplace  14 . 
     To this end, the improved fire grate  10   a  may be expandable in the horizontal direction similar to the fire grate  10  discussed above. In particular, the improved fire grate  10   a  may have one or more horizontal expansion sleeves  100   a, b  and  c . The horizontal expansion sleeves  100   a, b, c  may be sized and configured to snugly receive horizontal tubes  102   a, b  of the upper right section  104  and horizontal tubes  102   c, d  of the upper left section  106  of the improved fire grate  10   a . The horizontal expansion sleeve  100   c  may be sized and configured to snugly receive horizontal tubes  102   e, f  of the lower right section  108  and lower left section  110  of the improved fire grate  10   a . The horizontal tubes  102   a - f  may be slid into and out of the horizontal expansion sleeves  100   a - c  to fit the improved fire grate  10   a  horizontally within the combustion chamber  12  of the fireplace  14 . Once the width  22   a  of the improved fire grate  10   a  is adjusted to the width of the combustion chamber  12  of the fireplace  14 , set screws  112   a, b, c, d  are engaged such that the width  22   a  of the improved fire grate  10   a  does not change during use. In particular, the horizontal expansion sleeves  100   a, b  may have a threaded through hole which receives the set screws  112   a - d . The set screws  112   a - d  engage the exterior surfaces of the horizontal tubes  102   a - d  such that the horizontal tubes  102   a - d  cannot slide within the expansion sleeves  100   a - b  once set. 
     The horizontal expansion sleeves  100   a, b  may have holes  114  equidistantly spaced apart from each other (e.g., 1″ apart). A first set of holes may be oriented to blow air horizontally forward as shown in  FIG. 8 . A second set of holes  114  may be oriented to blow air directly downward as shown in  FIG. 8 . The downwardly directed holes  114  may also be equidistantly spaced apart from each other (e.g., 1″). Moreover, the downwardly directed holes  114  may be offset from the forwardly directed holes  114  (e.g., ½″), as shown in  FIG. 7 . Holes  114  and  116  may be formed in expansion sleeve  100   b  and horizontal tubes  102   b, d  in a similar fashion as the holes  114 ,  116  in expansion sleeve  100   a  and tubes  102   a, c . As shown in  FIG. 8 , one set of holes  114 ,  116  are oriented rearward of the improved fire grate  10   a  and one set of holes  114 ,  116  are oriented downward. When the width  22   a  in the improved fire grate  10   a  is adjusted, the width  22   a  is adjusted by the spacing of the holes  114 ,  116 . In this example, the width  22   a  of the improved fire grate  10   a  is adjustable in 1″ increments. The reason is that for air to blow out of the holes  114 ,  116  which form the air outlet holes  36   a , the holes  114 ,  116  must be aligned to each other. To align the holes  114 ,  116 , a pin  118  may be inserted into the holes  114 ,  116  prior to engagement of the set screws  112   a, b  and  112   c, d.    
     Once the width  22   a  of the fire grate  10   a  is set, the horizontal height  120  is adjusted. To this end, the improved fire grate  10   a  may have vertical expansion sleeves  122   a, b . The upper right section  104  and the lower right section  108  of the improved fire grate  10   a  may have vertical tubes  124   a, b  that are sized and configured to be received within the vertical expansion sleeve  122   a . Likewise, the upper left section  106  and the lower left section  110  may have vertical tubes  124   c, d  which are sized and configured to be received into the vertical expansion sleeve  122   b . To adjust the height  120  of the improved fire grate  10   a , the tubes  124   a - d  are slid into and out of the expansion sleeves  122   a, b  until the appropriate height  120  of the improved fire grate  10   a  is achieved. Preferably, the height  120  of the fire grate  10   a  is sized and configured to fit within the combustion chamber  12  of the fireplace  14 . As the tubes  124   a - d  are slid into and out of the vertical expansion sleeves  122   a, b , the tubes  102   e, f  are also slid into and out of the horizontal expansion sleeve  100   c  since the tubes  124   a - d  are skewed and not parallel with each other. As such, when the width  22   a  of the improved fire grate  10   a  is being adjusted, set screws  112   e, f  are not set. The tubes  102   e, f  are allowed to slide into and out of the expansion sleeve  100   c . After the height  120  of the improved fire grate  10   a  is adjusted, the set screws  112   e, f  are engaged. Additionally, set screws  126   a - d  are set to prevent movement of the tubes  124   a - d  within vertical expansion sleeves  122   a, b.    
     The tubes  102   a - f  may be sized and configured to snugly fit within expansion sleeves  100   a - c . However, it is also contemplated that the reverse orientation is possible. The expansion sleeves  100   a - c  may be slid into the tubes  102   a - f . The same is possible with the vertical expansion sleeves  122   a, b . Also, preferably, there is no more than 1/32″ gap between the expansion sleeves  100   a - c  and tubes  102   a - f  as well as between tubes  124   a - d  and expansion sleeves  122   a, b . For example, the outer diameter of the tubes  102   a - f  and tubes  124   a - d  may be no more than 1/16″ smaller than the inner diameter of the expansion sleeves  100   a - c  and vertical expansion sleeves  122   a - b . It is also contemplated that a fire resistant putty may be disposed about the periphery of the distal ends of the expansion sleeves  100   a, b  and expansion sleeves  122   a, b  prevent leakage of air. 
     Baffle plate  55   a  may be disposed at the rear of the improved fire grate  10   a . To this end, a U-channel  128   a, b  may be attached to medial sides of the expansion sleeves  122   a, b . The baffle plate  55   a  may be slid into the U-channels  128   a, b  to hold the same in place during use. To adjust the width and height of the baffle plate  55   a , the baffle plate  55   a  may be provided to the consumer in an oversized state. Once the appropriate height  120  and width  22   a  of the improved fire grate  10   a  is achieved, the consumer may cut the baffle plate  55   a  to size. The same is also possible for baffle plates  54  which are suspended via tabs  56   a  (refractory tabs). 
     Referring now to  FIG. 8 , baffle plates  74   a, b  (deflector plates) are shown. The baffle plates  74   a, b , and more particularly, a lower edge  81  of the baffle plates  74   a, b  extend to the ground of the fire box of the fireplace  14  to mitigate air from flowing in front of the baffle plates  74   a, b  to the rear of the baffle plates  74   a, b . To further mitigate air transfer in front of to the rear of the baffle plates  74   a, b , baffle plate extensions  83   a, b  (see  FIG. 7 ) may be slid into pipes  85   a, b  and adjusted to overlap the baffle plates  74   a, b . The lower edges  87  of the baffle plate extensions  83   a, b  may extend to the ground of the fire box to prevent flow of air underneath the baffle plate extensions  83   a, b . Additionally, the baffle plate extensions  83   a, b  may be extended outwardly such that lateral edges  89  may extend to side surfaces of the fire box of the fireplace  14 . As such, the baffle plates  74   a, b  and the baffle plate extensions  83   a, b  form a barrier to prevent flow of air underneath and around the sides of the baffle plates  74   a, b . The improved fire grate  10   a  may be suspended above the ground via spacers  130  having a height sufficient to allow the heat source  18  between the improved fire grate  10   a  and the ground. Retaining members  70   a, b  are also shown. Referring now to  FIG. 8 , the set screws  112  are not protruding out of the backside of the improved fire grate  10 ,  10   a . As such, the improved fire grate  10 ,  10   a  may be backed up and contact the backside of the combustion chamber  12 . 
     Referring now to  FIGS. 10-13 , a second embodiment of the mixing chamber  79   a  is shown. The two mixing chambers may be in fluid communication with a manifold  92   a  by way of orifices  97   a  (see  FIG. 11 ). Flammable gas is introduced into the manifold  92   a  through flammable gas inlet  94   a . The flammable gas is then flowed through into the mixing chamber  79   a  which is combined with fresh air through air inlets  132  and  134 . The air inlets  132  may be threaded to allow attachment of an air conduit  93  that can be directed toward the front of the fireplace  14  so that fresh air may be flowed into an air chamber  136  (see  FIG. 11 ). In contrast to the embodiment shown in  FIG. 9 , it is contemplated that one of the two air inlets  132  may be plugged with an air conduit attached to the unplugged air inlet  132 . The determination of which air inlet  132  to plug and which air inlet  132  to attach to an air conduit  93  is dependent on the orientation of the mixing chamber  79   a . Preferably, the unplugged air inlet  132  is directed to a front open space of the fireplace  14 . The air conduit  93  may be attached to the unplugged air inlet  132  and may provide fresh air into both of the mixing chamber  79   a  by way of the common air chamber  136 . Air flow paths  138  are shown in  FIG. 11 . 
     Referring now to  FIG. 12 , the mixing chamber  79   a  may have curved back surfaces  140 . As flammable gas flows through the orifices  97   a  in the direction of arrows  142 , the flammable gas enters the mixing chamber  79   a  and mixes with fresh air introduced into the mixing chamber  79   a  by way of air inlets  134  (see  FIG. 11 ). The mixed air/flammable gas is flowed through the mixing chamber  79   a  in the direction of arrows  144 . The curved back surfaces  140  are optional and are meant to assist in providing less turbulence by guiding the mixture to the mixed flammable gas/air outlets  146  that may be connected to the fire sources  62 . 
     Referring now to  FIG. 13 , fresh air may enter the air chamber  136  by way of air inlets  132 . It is contemplated that one of the air inlets  132  may be plugged while the other air inlet is attached to an air conduit  93 . It is also contemplated that both of the air inlets  132  are unplugged with two separate air conduits attached to the air inlets  132 . After air enters the air chamber  136  by way of the air inlets  132 , the air is introduced into the mixing chamber  79   a  by way of air inlets  134 . Referring now to  FIG. 14 , an alternate embodiment of the air chamber  136  is shown. In particular, air chamber  136   a  may have a trapezoidal configuration. Sidewalls  148  may be skewed so that air conduits  93  that are attached to one or both of the air inlets  132  can be directed toward the side as shown in  FIG. 9 . 
     The tubular supports  38   a, b , vertical tubes  124   a, b  and sleeves  122   a, b  have been shown as being generally round tubes. However, it is also contemplated that these tubes  38   a, b ,  124   a, b ,  122   a, b  may also be square, rectangular or other configurations. A generally flatter rectangular tube will allow the wood to be placed further back on the fire grate. 
     The above description is given by way of example, and not limitation. Given the above disclosure, one skilled in the art could devise variations that are within the scope and spirit of the invention disclosed herein, including various ways of fixing the width  22  of the improved fire grate after adjustment. Further, the various features of the embodiments disclosed herein can be used alone, or in varying combinations with each other and are not intended to be limited to the specific combination described herein. Thus, the scope of the claims is not to be limited by the illustrated embodiments.