US 3623470 A
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United States Patent  Inventor Murray 0. Wilholte Nashville, Tenn.
 Appl. No. 15,794
 Filed Mar. 2, 1970  Patented Nov. 30, 1971 [7 3] Assignee Telnco, Inc.
 GAS FIREPLACE 8 Claims, 5 Drawing Figs.
 U.S.Cl 126/121, 126/90 R, 126/92 R, 126/116 B. 126/127  Int. Cl. F24c 3/00  Field Search 126/127, 128. 129, 121, 120, 116, 116 B, 110,86, 89,90, 92. 92 C  References Cited UNITED STATES PATENTS 2,270,940 l/l942 Elmore 126/121 2,762,362 9/1956 Nielsen 126/92 3,254,642 6/1966 Tuttle 126/[27 X 3,291,116 12/1966 Brooks 126/92 3,3 82,861 5/1968 Peterson 126/92 FOREIGN PATENTS 925,365 5/1963 Great Britain 126/90 Primary Examiner-Charles J Myhre Attorney-Cushman, Darby & Cushman ABSTRACT: A wall-mounted, gas-fired fireplace unit includes a decorative simulated-log gas burner and a gas-fired, room-heating unit disposed behind the logs within a common decorative cabinet. Room air passes in heat exchange relationship with the exterior of the heating unit, while hot combustion products from the log burner are directly vented to avoid heating room air. A manually operable control system permits the log burner and heating unit to be used separately or together.
INVI-IN'I'UR ATTORNEYS GAS FIREPLACE This invention relates to a combination fireplace and fluid fuel heater and in particular to an improved structure which includes both a decorative simulated-log gas burner and a gasfired heating unit adapted to heat room air.
A gas fireplace typically includes a simulated-log structure and an associated gas burner for producing a flame which in combination with the log structure gives the appearance of burning logs. In some constructions the heat generated by the burning gas is utilized to warm the room air by indirect heat exchange between the combustion products and the room air. In other constructions products can be vented without any appreciable heat exchange with room air. Sometimes an additional gas-fired heating unit is employed in conjunction with the simulated-log burner. So far as is known, all of these known structures suffer from a lack of versatility in that little or no control can be exerted separately over the heating and decorative functions of the devices. As a result, these known devices have the disadvantage of tending to overheat the room when used during warm weather or in mild climates.
It is therefore one object of the present invention to provide a combination gas-operated fireplace and heater unit in which a decorative simulated-log burner and a gas space heater can be operated separately or together. In the preferred embodiment, rather than using a conventional gas control unit for each of the two burners, there is provided a special simplified control unit which achieves separate control of the burners with a minimum ofparts.
A further object of the invention is to provide a combination gas-fired fireplace and heater having an improved internal arrangement of its major parts, particularly the relative positions of the simulated-log burner and the heating unit and the construction of the parts which achieve venting of the combustion products. In particular, there is provided a special draft hood which receives combustion products separately from the simulated-log burner and from the heating unit and channels them into a common main flue.
A further object of the invention is the provision ofa special simulated-log structure and burner combination which produces a particularly pleasing decorative effect during operation. In the preferred construction the simulated-log structure is an integral ceramic structure having the form ofa plurality of logs stacked one on the other with spaced apart openings therebetween to permit flames from the underlying burner to project above the upper surface of the integral log structure.
The invention will further understood from the following detailed description of an illustrative embodiment taken with the drawings in which:
FIG. 1 is a front elevational view, partly broken away, ofa fireplace construction embodying the principles of the present invention;
FIG. 2 is a sectional view taken on the line 22 of FIG. 1;
FIG. 3 is a fragmentary perspective view of the burners and the control system therefor;
FIG. 3A is a schematic sectional view of the main control valve of FIG. 3, and
FIG. 4 is a vertical transverse sectional view through the simulated-log structure.
Referring to FIGS. 1 and 2 there is shown a gas fireplace construction which includes among its major components a decorative simulated-log structure disposed within an open-front hearth box 12 and an upright gas heater unit 14 disposed behind the hearth box 12. An external cabinet 16, open at the front of the hearth box 12, surrounds the internal parts as is conventional in the art. In the illustrated embodiment the fireplace is adapted to be mounted on a wall 17 ofa room, and the cabinet is comprised of front and sidewalls l8 and 20 and suitable wall mounting plates such as shown at 22 and rear heat shields such as shown at 24 and 26. The lower portion ofthe cabinet below the hearth box 12 and heater unit 14 houses a gas supply and control system 28 illustrated schematically in FIG. 2 and more in detail in FIG. 3.
The hearth box 12 includes a rear wall 30, spaced-apart sidewalls 32 and 34 and a top wall 36 from the central portion of which there extends an upwardly and rearwardly inclined flue conduit 38 having an open upper end 40. In the illustrated embodiment the flue conduit 38 is defined between a sheet of metal 42 extending upwardly from the top wall 36 of the hearth box 12 and a relatively narrow sheet metal channel 44 having flanged edges secured to the front face of the sheet 42. The upper end of the flue conduit 38 is restricted in cross section as by means of an angle piece 46 in order to achieve proper draft characteristics. The front of the hearth box is sealed with a glass panel 47.
The hearing unit 14 includes a combustion chamber which may be of the now conventional construction which includes spaced-apart front and rear walls 50 and 52 secured together along their edges 54 to define a space through which combustion products travel in indirect heat exchange with the room air in contact with exterior surfaces of the walls 50 and 52. The upper end of the rear wall 52 is provided with a centrally located hole 56 through which combustion products pas into a suitable outlet structure 58 having an upwardly directed open-ended discharge tube 60. The end of the tube 60 is restricted in cross section as by a lip 62 in order to achieve proper draft characteristics. The entire combustion chamber is supported within the cabinet 16 in any suitable manner as by a floor-supported bracket 63 or the like located in the lower portion of the cabinet.
The combustion chamber is in communication with the hearth box 12 through a centrally located opening 64 in the lower part of the front wall 50 of the combustion chamber and a complementary opening in the rear wall 30 of the hearth box 12, there being provided for this purpose a suitable tubular connection 68. Two gas burner tubes 70 and 72 are disposed at the elevation of the openings 64 and 68, the forward burner 70 being located within the hearth box 12 below the simulated-log structure 10 and the rear burner 72 being located in the combustion chamber. In the interest of simplicity and economy of construction, a single pilot burner 74 is disposed between the burners and for igniting both the burners. Combustion air from the room reaches the burners by entering through louvers 76 in the cabinet sidewalls near the lower ends thereof and then passing upwardly through an opening 78 in the bottom wall of the hearth box 12 and past a sheet metal radiation shield 80.
Combustion products from the burners 70 and 72 are vented to the outside of the building through a common main flue pipe 82 which may extend upwardly through the roof or upwardly and then horizontally through the wall 17. The combustion products from the inclined flue conduit 38 and from the discharge tube 60 from the combustion chamber enter the lower end ofthe lower end of the main flue pipe 82 by way ofa common draft hood 84 which neutralizes downdrafts likely to be caused by ambient wind conditions while ensuring proper operating updraft during operation.
In the illustrated construction the draft hood 84 is a generally boxlike sheet metal structure of lesser width than the combustion chamber and defined by a rear wall 86, two laterally spaced-apart sidewalls one of which is shown at 88, a partial bottom wall 92 and an inclined front wall 94 extending downwardly a substantial distance below the bottom wall 92. The front wall 94 is spaced away from the parts 42 and 44 which form the flue conduit 38 so as to define a relief opening of substantial cross section. The relief opening 90 functions in the event of a blocked main flue to carry combustion products out of the draft hood 84. The upper end of the flue conduit 38 projects a short distance into the draft hood at a location directly in front of the partial bottom wall 92, and the upper end of the discharge tube 60 projects through the partial bottom wall 92. An L-shaped upwardly and rearwardly inclined antidowndraft baflle 96 is disposed above the upper ends of the flue conduit 38 and the tube 60, and the flow paths for combustion products are shown by the arrows in FIG. 2.
The top wall of the draft hood 84 is provided with an upwardly extending discharge pipe 98 which is telescoped into the lower end of the main flue 82. At this location the fireplace cabinet 16 is provided with an internal top wall structure. in the illustrated embodiment the wall structure is defined by two vertically spaced-apart horizontal plates 100 and 102 which are suitably apertured to allow passage of the main vent therethrough. In order to minimize heating of room air by operation of the simulated-log burner, the upper plate is provided with a layer of thermal insulation 104, and the inner surface of the front wall 20 of the cabinet 16 is also covered with thermal insulation 106. On the other hand, room air is intended to be heated by the heating unit 14, and to this end the cabinet sidewalls 18 are interrupted at the location of the hearth box, as shown at 108 in HO. 1, to allow entry of room air. Louvers 110 in the sidewalls at the location of the draft hood allow passage of warmed air back into the room. A flexible traversing firescreen 112 is mounted in front of the glass plate 47 and around the interrupted sides of the cabinet 16. A vertical metal plate 114 with louvers 116 therein is disposed at each side of the space to cover the internal parts from view while permitting entry of room air.
FIG. 3 illustrates the two burners 70 and 72, arranged parallel to each other, and the control system by means of which the burners may be used together or separately. The fireplace burner 70 includes an elongated hollow cast iron body 118 and an integral venturi-type gas and air inlet structure 120 which merges with a hollow projection 122 on the body 118. The upper surface of the body 118 is provided with a plurality of spaced-apart ports each of which is fitted with a tip 124 designed to produce a tall, irregular or flickering flame. In the illustrated embodiment the tips are ceramic disks perforated with a plurality of radial slots 126. The spacing between the tips 124 is irregular, and some of the tips are offset with respect to others in order to conform generally to the pattern of holes in the ceramic log structure 10. A pilot light 128 is disposed adjacent the outer end of the projection 122, and a series of small ignition ports 130 is provided in the projection 122 is order to carry the initial flame to the tips 124. Additional ignition ports 130 are provided between some of the tips 124 where the spacing is too great to permit flame propagation between tip 124 and its neighbor.
The heating unit burner 72 is a separate structure although it is physically connected to the projection 122 of the fireplace burner 70 as by suitable brackets (not shown). The burner 72 may be of any conventional design which is compatible with the dimensions of the heating unit 14 (FIG. 2) 106 in which it is employed. The pilot light 128 is arranged so that it will light both the burner 72 and the ignition ports 122 of the burner 70.
The control system for burners 70 and 72 includes thermostatic and manual valving which permit operation of the burners together or separately by means of two manually rotatable control knobs 132 and 134 mounted at some convenient location on the exterior of the cabinet 16. The knob 132 controls a conventional off-on valve 136 which supplies gas to the venturi mixer 120 of the burner 70 through an extension 137, there being provided a rigid connecting rod 138 between the knob and the valve. Gas flow to the burner 72 is by way of a line 139 and is controlled by a conventional adjustable thermostatic valve located within a main control valve 140, the arrangement including a conventional thermostatic element 142 and the usual tubes 144,146. Rotation of the knob 134 to a desired temperature setting has the effect of opening the valve when the room temperature drops to a predetermined temperature and closing the valve when room temperature reaches a predetermined higher temperature. Adjusting the knob 134 to, for example. a setting of 40 F. has the practical effect of turning off the heating unit 14.
The main control valve 140 may be of conventional construction with one important exception, and in the interest of simplicity the major parts of the valve 140 are illustrated schematically in FlG. 3A. Valves of this kind are conventionally constructed of two basic valve components 140:: and 14011,
one of which embodies a safety feature in the form of a shutoff valve which cuts off the gas flow in the event that the pilot light 128 becomes extinguished. The other component 1401? includes the previously mentioned adjustable thermostatic valve, illustrated in FIG. 3A at 152.
Conventionally, the safety valve 150 is constructed in such a manner that it is held open by the electric current generated by a thermocouple 156 disposed to receive heat from the flame of the pilot light 128. If the pilot light 128 becomes extinguished, the valve 150 closes, and no gas can flow to the thermostatic valve 152.
in the illustrated construction the valve component 1400 is provided with a first outlet 149 for the burner 72 and a second outlet 151 for the burner 70. However, the gas passing through the safety valve 150 passes first into a chamber 153 in the valve component 140)). Gas from the chamber 153 can pass to the outlet 149 only when the thermostatic valve 152 is open, while gas is always available to the outlet 151 by means of a bypass hole 155 drilled through a wall 157 within the body of the valve component 140b, Ordinarily the component 140i: is manufactured with a single operational gas outlet, such as the outlet 149. However, it is customary for the component to have one or more nonoperating, dead end outlets facing in various directions so that a conveniently located outlet may be selected for making the desired connection, it being only necessary to drill a hole between the downstream side of the valve 152 and the appropriate outlet. According to the present invention, however, two outlets are employed, and one of them bypasses the valve 152. By this arrangement one safety valve 150 serves both burners 70 and 72, while at the same time the fireplace burner 70 can be operated independently of the thermostatic valve 152.
The heat output of the burner 70 is considerably less than the output of the burner 70. For example, a burner of 20,000 B.t.u. has been found to provide the necessary decorative flame, and actual heat to the room may be only 10,000 Btu. due'to the intentionally inefficient construction of the vent conduit 38. On the other hand the burner 72 may be designed to produce 35,000 B.t.u., 75 percent of which will be transferred to the room air by the walls 50 and 52 of the combustion chamber.
FIG. 4 illustrates the construction of the simulated-log structure 10 and its relationship to the burner 70. The structure 10 is an integral refractory ceramic structure simulating four logs piled one on another and having a plurality of relatively large horizontally elongated openings 160 extending vertically through the structure at randomly spaced-apart locations between simulated logs. The openings 160 correspond to the naturally occurring spaces between piled logs resulting from the irregular diameters of the logs or the presence of protrusions on the logs. in practice, the openings 160 will be horizontally spaced apart in both a longitudinal and transverse direction with respect to the axes of the logs, and will conform generally to the pattern of tips 124 on the burner 70. This arrangement, in operation, permits the tall flickering flames to project upwardly through the openings and above the upper surfaces of the ceramic structure 10.
What is claimed is:
1. A gas-fired fireplace comprising:
a simulated-log structure including a first gas burner;
a flue conduit extending from an open lower end above said first burner upwardly to an open upper end;
a heating unit disposed behind said simulated-log structure and including a vertically elongated combustion chamber of greater height than said structure, said combustion chamber being formed by spaced-apart front and rear walls joined together along their edges and a second gas burner disposed within the lower part of said combustion chamber, said combustion chamber having a combustion gas outlet aperture at its. upper end; an upwardly extending main vent conduit having a lower end common to both said flue conduit and said combustion gas outlet;
wall means surrounding said flue and at least that portion of said combustion chamber which is above said simulatedlog structure and defining with said combustion chamber a space for heating room air, said wall means being provided with at least one room air inlet aperture at an elevation near the lower end of said combustion chamber and at least one heated air outlet aperture at an elevation near the upper end of said combustion chamber; and
manually operated gas supply means for selectively supplying gas to said first and second burners.
2. A gas-fired fireplace comprising:
wall means defining an open-front hearth box having an upwardly extending flue conduit;
a gas-fired heating unit disposed behind said hearth box in spaced relation to the rear wall of said hearth box, said heating unit including a vertically disposed combustion chamber formed by spaced-apart front and rear walls joined together along their edges, said combustion chamber having a combustion gas outlet at its upper end and said front wall having an aperture opening into the rear ofsaid hearth box;
a first gas burner disposed within said combustion chamber at the location of said aperture;
simulated-log burner means including a second gas burner disposed within said hearth box and closely adjacent said first burner;
gas supply and control means for said first and second burners including a single pilot burner disposed in a position to light both burners.
3. A gas-fired fireplace as in claim 2 wherein said second gas burner is constructed with a plurality of relatively large upwardly facing ports each of which is fitted with a gas distribution plug which effects a tall flame during operation, said fireplace further including an integral ceramic structure simulating a plurality of logs piled one on the other, said ceramic structure overlying said ports and having a plurality of spacedapart relatively large openings extending upwardly therethrough at locations between the simulated logs, said openings permitting the tall flames from said gas distribution plugs to project above the upper surfaces of said integral ceramic structure.
4. A gas-fired fireplace as in claim 2 wherein said gas supply and control means includes:
a main gas inlet conduit, a first gas feed line for delivering gas to said first burner, a manually adjustable thermostatically controlled valve connected between said inlet conduit and said first gas feed line, a second gas feed fine for delivering gas to said second burner connected between said main gas inlet and said then'nostatically controlled valve so as to bypass the latter, and a manual off-on valve connected into said second gas feed line whereby said first and second burners may be operated together or separately.
5. A gas-fired fireplace comprising:
a simulated-log gas burner;
wall means defining an open-front hearth box surrounding the top, bottom and sides of said simulated-log gas burner;
a flue conduit extending upwardly from the top of said hearth box and having an open upper end;
a gas-fired heating unit disposed behind said hearth box, said unit including a combustion chamber adapted to heat room air by heat-exchange between the exterior surfaces of said combustion chamber and room air, said combustion chamber being provided with an upwardly extending combustion gas outlet tube having an open upper end;
a draft hood disposed above said hearth box to receive combustion products from said flue conduit and from said combustion gas outlet tube, said draft hood being defined by front, side, rear and top walls which form a space into which the open upper ends of said flue conduit and said outlet tube project; and
a main flue conduit extending upwardly from the top of said draft hood for carrying off all combustion products.
6. A gas-fired fireplace as in claim 5 including a downdraft baffle located within said hood in overlying and spaced relation to the upper ends of said flue conduit and said outlet tube, the bottom of said draft hood being open and unobstructed at a location forward of said flue conduit.
7. A gas-fired fireplace as in claim 6 including a cabinet surrounding said flue conduit, draft hood and combustion gas outlet tube and defining with said combustion chamber a space for heating room air, said cabinet being provided with at least one room air inlet aperture near the lower end of said combustion chamber and with at least one heated room air outlet aperture at a higher elevation at the level of said draft hood.
8. A gas-fired fireplace comprising:
a room-heating unit including a first gas burner located in a combustion chamber which is adapted for heating room air;
a decorative simulated-log structure disposed in front of said heating unit and including a second gas burner;
a gas supply and control system adapted for manually operating first and second burners separately or together, said simulated-log structure, heating unit and supply and control system being disposed within decorative cabinet means having a hearth opening which exposes said simulated-log structure;
said gas supply and control system including a main gas inlet conduit, a first gas feed line for delivering gas to said first burner, a valve connected between said inlet conduit and said first gas feed line, temperature-responsive manually adjustable control means operatively connected to said valve for opening and closing said valve at preselected low and high room temperatures, respectively, a second gas feed line for delivering gas to said second burner connected between said main gas inlet and said valve so as to bypass the latter, and a manual off-on valve connected into said second gas feed line.