Patent Publication Number: US-4320740-A

Title: Fireplace heater with reflector, heat retainer, forced draft and grate

Description:
BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the fireplace heater of the present invention with the fireplace being diagrammatically illustrated to show the relationship of the present invention to an existing fireplace. 
     FIG. 2 is a vertical sectional view taken substantially upon a plane passing along section line 2--2 of FIG. 1 illustrating the specific structural details of the fireplace heater. 
     FIG. 3 is a sectional view, on an enlarged scale, illustrating the manifold structure and the relationship of the air inlet and air exhaust pipes. 
     FIG. 4 is a detailed sectional view of the heat chamber illustrating the heat retaining plate in elevated position with a pivotal prop securing the plate in this position to enable large logs to be placed into the fireplace heater. 
     FIG. 5 is a fragmental plan view of the forced draft device disposed along one side of the fireplace heater. 
     FIG. 6 is a sectional view of the forced air draft device illustrating further structural details thereof. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now specifically to the drawings, the fireplace heater of the present invention is generally designated by reference numeral 10 and is installed in a conventional fireplace opening 12 having the usual damper arm (not shown) and rests on the hearth 14 inwardly of a closure device 16 for the fireplace opening 12 which may be in the form of folding or sliding transparent glass doors or the like, the details of which are not shown, with the lower end of the closure member 16 including an air panel 18 to be described in detail hereinafter. The fireplace heater 10 is disposed with the rear portion thereof to the rear wall 20 of the fireplace, all of which represents conventional fireplace structure with the dimensional characteristics of the fireplace heater varying depending upon the dimensions of the fireplace in which the fireplace heater is installed. 
     The fireplace heater 10 includes a grate for receiving logs or other combustible fuel with the grate generally being designated by numeral 24 and including two sets of grate pipes including air inlet grate pipes 26 and air exhaust grate pipes 28 which are disposed in spaced parallel relation to each other and include a generally horizontally disposed lower portion, an upwardly curved rear portion and a forwardly and upwardly inclined upper portion as illustrated in FIG. 2. All of the grate pipes 26 and 28 are covered by a grate 30 as illustrated in FIG. 2 with the grate 30 setting on the grate pipes 26 and 28 and conforming to the shape and configuration of the forward and curved portion of the grate pipes. Interconnecting the forward end portion of the grate pipes 26 and 28 is a horizontally disposed lateral manifold 32 with the air inlet grate pipes 26 being communicated with the interior of the manifold 32 and the air exhaust grate pipes 28 extending through the manifold 32 and terminating in forwardly projecting ends 34 which also project through the air panel 18 so that the terminal forward ends of the projecting ends 34 of the air exhaust grate pipes 28 terminate substantially flush with the forward surface of the air panel 18 under the closure member 16 for discharge of heated air forwardly along the hearth or floor level. Air inlet is provided to one end of the manifold 32 by an air circulating fan 36 having a pipe or conduit 38 communicating with one end of the manifold 32. As illustrated, the air circulating fan 36 and the conduit 38 are disposed outwardly of the fireplace and may be oriented on the hearth 14 with the conduit 38 including appropriate elbows or other fittings so that it extends through an opening 40 in the air panel 18 and extends into and connects with an end cap 42 having a fitting 44 to which the conduit 38 is connected with the end cap 42 being releasably secured to the manifold 32 by screws or the like. The end cap 42 may be interchanged with a solid end cap 46 on the opposite end of the manifold 32 to enable the air circulating fan 36 and the conduit 38 to be optionally oriented to either the left or right side of the fireplace heater. 
     The upper ends of the grate pipes 26 and 28 are rigidly connected to and communicated with a horizontally disposed, transversely extending heat chamber 48 which has removable end caps 50 thereon corresponding to the end caps 46 or 42 so that conduits can be connected thereto, if desired, for discharge of heated air forwardly from the fireplace at any elevation desired or into duct works for conveying the heated air to any desired location. The heat chamber includes rigid nipples 52 along the bottom thereof which are rigidly affixed to the grate pipes 26 and 28 in any suitable manner such as by using set screws, or the like, which may also be used to connect manifold 32 to the pipes to enable disassembly and assembly of the components thereby enabling storage and shipment when in a compact knocked down condition. The heat chamber 48 communicates all of the grate pipes so that air entering the heat chamber from the air inlet grate pipes 26 will exit the heat chamber through the air exhaust grate pipes 28 for discharge of the heated air through the terminal projecting ends 34 at floor level. Any suitable number of grate pipes may be employed with alternate pipes being inlet and exhaust pipes or, if desired, a larger number of the exhaust pipes may be utilized to provide for expansion of the heated air during passage through the pipes and heating chamber. Depending upon the nature and size of the fire, heated air may be discharged into the room at floor level at approximately 500° F. For additional efficiency and heat, end tubes can be added to either end of the heat chamber 48 by utilizing an end cap 42 rather than an end cap 50 with such end tubes or conduits including elbows or any other fittings which can be swiveled in any direction for piping heated air into any desired area. 
     This unit is a stable unit and is supported from the hearth by the lower surface of the manifold 32 and downwardly projecting supporting legs 54 adjacent the juncture between the horizontal portion and the upwardly curved portion of the pipes. Thus, this unit can be installed in the fireplace and constitutes a stable, self-supported unit and may be used with the air panel 18 when a closure member 16 is employed. If a different type of closure member is employed for the fireplace opening, in some instances, the air panel 18 may not be used or may be modified. The air panel 18 is a rectangular, hollow filler member between the lower edge of the closure member 16 and the hearth 14 and may be secured to the lower end of the closure member 16 in any suitable manner with preformed openings formed therein or openings may be easily cut therein to receive the projecting ends 34 of the air exhaust grate pipes 28. The air circulating fan 36 may be of conventional construction or constructed in accordance with our co-pending application Ser. No. 955,171, filed Oct. 27, 1978, with the source of the air being the surrounding space or room or, if desired, air may be taken from the exterior of the house especially when a portion of this air will be used to support combustion through a forced draft assembly described hereinafter, thereby reducing heat loss up the chimney opening 22 due to the draft conditions induced within the interior of the house by the discharge of combustion products. 
     A reflector plate 56 extends transversely in front of the upper portions of the grate pipes 26 and 28 and the lower edge of the heat chamber with the upper edge of the reflector plate 56 being received behind a downwardly extending plate or flange 58 rigidly fixed to the front surface of the heat chamber 48 and extending downwardly therefrom in slightly spaced relation to the upper end portions of the grate pipes 26 and 28, so that the upper edge of the reflector plate 56 may be placed behind the plate 58 and moved upwardly so that rearwardly inclined tabs 60 formed in the lower edge of the plate 56 may pass over the top edge of the grate 30 and the reflector plate 56 then moved downwardly slightly so that the upper edge of the grate 30 is received between the tabs 60 and the bottom edge of the reflector plate 56 as illustrated in FIG. 2. The tabs 60 may be simply formed by lancing the lower edge of the reflector plate 56 and the tabs rearwardly deflected in a manner well-known in the art so that reflector plate 56 will be retained in position but can be easily assembled and disassembled when desired. The reflector plate will reflect heat forwardly from the fireplace heater so that radiated heat will be discharged into the room or space in which the fireplace heater is used. 
     A heat retaining plate 62 extends transversely of the fireplace heater substantially throughout the heat chamber 48 with the plate 62 extending normally forwardly and downwardly from the heat chamber 48 but the plate 62 is spaced vertically from the top surface of the heat chamber 48 so that combustion products may pass between the heat retaining plate 62 and the heat chamber 48. To provide for this spaced relationship, the rearward edge of the heat retaining plate 62 is pivotally attached to the top surface of the heat chamber 48 by hinge structures 64 which are in spaced relationship to each other and which space the heat retaining plates 62 from the heat chamber 48. The hinge structures 64 are located at the rear edge of the heat chamber 48 and the rear edge of the plate 62 and the forward edge of the heat chamber 48 is provided with a plurality of upwardly projecting stop pins 66 which engage the undersurface of the heat retaining plate 62 to maintain the heat retaining plate 62 in generally spaced parallel relation to the top surface of the heat chamber 48 as illustrated in FIG. 2 but with the forward edge of the heat retaining plate extending forwardly beyond the heat chamber 48 and terminating in a downwardly extending narrow flange 68 at its forward edge. This structure enables the heat retaining plate 62 to move from its normal operative position as illustrated in FIG. 2 to an elevated position illustrated in FIG. 4 to enable placement of relatively large logs into the fireplace heater. In order to temporarily retain the heat retaining plate 62 in its open or elevated position as illustrated in FIG. 4, a pivotal prop 70 is attached to the undersurface of the plate 62 in a manner such that it will fall due to gravity into an inclined position with the lower end setting on heating chamber 48 to prop the heat retaining plate 62 in its open or elevated position when it is elevated to a position such that the prop 70 will assume a vertical position so that subsequent release of the plate 62 will cause the prop 70 to slide down and forwardly along the top surface of the heat chamber 48 and rest thereon. When it is desired to lower the plate 62 to its operative position, a conventional poker may elevate the plate and be engaged with the prop 70 adjacent its lower end and the lower end of the prop 70 may then be moved to its folded or collapsed position with the heat retaining plate 62 then being lowered to its operative position. 
     The forward portion of the grate 30 is upwardly inclined as at 72 so that it passes above the manifold 32 with the upwardly inclined portion 72 terminating in a downturned flange 73 and a pair of upstanding brackets 74 are rigidly secured thereto with the lower ends of the brackets 74 being inclined as at 76 and attached in any suitable manner to the inner surface of the upwardly inclined portion 72 of the grate 30. Attached to the brackets 74 is a log retaining plate 78 secured to the outer surface of the brackets 74 by fasteners 80 or the like which serves to retain logs, sparks and coals on the grate 30. As illustrated in FIG. 2, the space between the top edge of the log retaining plate 78 and the forward edge of the heat retaining plate 62 provides access to the interior of the fireplace heater and this space is closed by a cover plate 82 which has spaced tabs 84 formed in the lower edge thereof by lancing the lower edge of the cover plate 82 and deflecting the tabs 84 so that the downwardly opening notches formed thereby will be engaged over the top edge of the log retaining plate 78. The top edge of the cover plate 82 rests against the downwardly inclined flange 68 of the heat retaining plate 62 which is inwardly of the top edge of the log retaining plate 78 so that gravity will retain the cover plate in position. The cover plate is provided with a loop 86 on its outer surface adjacent the center upper edge thereof which facilitates the insertion of the poker hook, or the like, therein to lift the cover plate upwardly away from the heat retaining plate 62 and the log retaining plate 78 so that it can be set aside when logs or other combustible fuel is being added to the fireplace heater. Thus, with the heat retaining plate 62 in its operative position and the cover plate 82 in position, the logs or other combustible fuel supported on the grate 30 will effectively heat all the components and the combustion products will pass between the heat chamber 48 and the heat retaining plate 62 with the space for such passage being designated by reference numeral 88 which assures efficient heat transfer between the adjacent surface areas of the furnace heater and the air passing through the heat chamber 48. The structural components may be constructed of any suitable material having requisite strength characteristics and requisite characteristics to resist deterioration from high temperatures. 
     The end of the fireplace heater may be partially closed with an end plate or end plates 90 which conform with the inner surfaces of the grate 30 and log retaining plate 78. The end plate 90 is retained in position on the grate by two or more projecting tongues along the edges thereof which are received in slot-like openings 92 formed in the side edge portions of the grate 30 with the two tongues and slots being spaced longitudinally and generally in surfaces at the rearward curved portion of the grate and either in the horizontal portion adjacent the forward edge thereof or in the inclined portion 72 of the grate 30. 
     A forced draft assembly 94 is disposed alongside of the end of the fireplace heater adjacent the end edge of the grate 30 in generally parallel relation thereto and is in the form of a pipe 96 connected to the conduit 38 extending from the air circulating fan 36 into the manifold 32. The pipe 96 is connected to the conduit 38 adjacent its point of connection with the manifold 32 and is connected thereto in any suitable manner with the opposite end of the pipe 96 being plugged or closed so that the interior of the pipe is provided with air under pressure from the circulating fan 36. The pipe or tube 96 is provided with a plurality of longitudinally spaced holes 98 therein which are selectively opened and closed by a sliding sleeve 100 having corresponding holes 102 for selective registry with the holes 98. Any suitable means such as a pin and slot arrangement 104 interconnects the pipe 96 and the sleeve 100 to limit the longitudinal movement of the sleeve and to retain the sleeve 100 from becoming angularly displaced. An elongated operating rod 106 is connected to the sleeve 100 and extends outwardly generally in a parallel relation to the pipe 96 and terminates in an operating knob 108 outwardly of the manifold 32 and outwardly of the air panel 18 if the air panel is being used. A supporting prop 110 is attached to the inner end of the pipe 96 for support of the same from the hearth with the support leg or prop 110 being reversible so that the forced air draft assembly 94 may be used either to the left or to the right of the fireplace heater. Also, the connection between the operating rod 106 and the sleeve 100 is reversible in a similar manner so that the operating rod 106 will be disposed at the bottom inner portion of the air draft pipe 96 when it is placed at the opposite side of the fireplace heater. Our prior U.S. Pat. No. 3,930,490 also discloses a forced draft similar in function to draft assembly 94. 
     It is pointed out that the fireplace heater as disclosed fully contains the fire thus providing for a longer burning, low flame fire with heat being prevented from flowing directly up and out the chimney. Rather, heat must flow under the heat retaining plate and over and around the top heating chamber thus effectively extracting heat from the combustion products before these gases exit through the space provided between the top heating chamber and the heat retaining plate. Thus, high efficiency and intense heat is obtained since the cold air flows in and upwardly into the heating chamber and then downward for discharge into the room with the circulating air extracting heat from the combustion products throughout its passage through the fireplace heater. The removable cover plate 82 and the hinged heat retaining plate 62 enables large logs to be effectively loaded into the fireplace heater. The cover plate 82 may be lifted and easily handled, even when hot, with a conventional poker and the same poker may be used for lifting the front edge of the heat retaining plate 62 to move it to its elevated position and also used to move the prop to collapsed position to lower the heat retaining plate 62 after logs have been placed into the fireplace heater. The interchangeable end caps on the manifold and heat chamber enable the forced air circulating fan and forced draft assembly to be installed at either side of the fireplace heater. Also, end caps with nipples may be provided at either or both ends of the heat chamber to which conduits are connected for conveying heated air into any desired area. The optional end plates and optional forced draft assembly enables not only retention of the heat and fire but also adequate supply of combustion supporting air. If a forced draft is not desired or necessary, the usual draft at the lower end of the closure member may be employed for supplying combustion supporting air and the forward portion of the grate may be provided with a conventional slide draft to enable inflow of combustion supporting air into the area containing the logs or other combustible fuel. The heat reflector plate 56 prevents heat from being absorbed by the back wall of the fireplace and reflects radiant heat towards the front of the fireplace. Also, the construction of the various components enable assembly and disassembly thereof so that the components can be stored and shipped in a knocked down condition and then easily set up at the site of installation. For example, the pipes 26 and 28 may be connected to the manifold and chambers by a telescopic arrangement between short nipples and the ends of the pipes and a single screw extending through the nipples into engagement with the pipes, so that the plates are detachable from the tubes and detachable from each other. 
     The structure of the grate, forced draft and heat retainer is of one standard depth and is placed to the very back of the fireplace and is so designed that the back curvature of the heater allows for conventional construction of the fireplace having back wall tapering inwardly to the fireplace throat. Varying depths of fireplaces are provided for by simply varying the length of air tubes which are furnished to allow for the greatest depth fireplaces and which can easily be cut to desired length in the field. The grate simply sets on and over all the heater tubes, the grate being formed of one standard shape. 
     The grate is a very important and integral functioning part of the fireplace heater by providing a firebox that extracts the energy and heat to the highest degree of efficiency, adding a great measure of safety by providing a low, hot burning fire, prevents danger of sparks or logs rolling out or into glass doors, allows large logs to be used for continuous burning, allows for efficiently burning newspapers. The grate will outlast cast iron grates and can easily be repaired when burn through does occur. 
     The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.