US3180332A - Metal fireplace structures with air supply means for combustion chamber - Google Patents

Description

Apnl 27, 1965 H. GRUSHKIN 3,180,332

METAL F EPLACE STRUCTURES WITH AIR SUPPLY NS FOR COMBUSTION CHAMBER Filed April 30, 1962 2 Sheets-Sheet 1 FIG. 2

INVENTOR: HARRY GRUSHKIN BY I J ATT'YS April 27, 1965 H. GRUSHKIN' 3,180,332 METAL FIREPLACE STRUCTURES WITH AIR SUPPLY MEANS FOR COMBUSTION CHAMBER Filed April 30, 1962 2 Sheets-Sheet 2 FIG. 5

INVENTOR.

HARRY GRUSHKIN so Y ATT'YS United States Patent Filed Apr. 30, 1962, Ser. No. 190,958 3 Claims. (Cl. 126- 121) This invention, in general, relates to improvements in I fireplace structures and more particularly relates to fireplace structures embodying means for supplying outside air instead of room air to the fireplace to support combustion. v

Virtually all houses in cool and cold climates today are heated by a central heating system. The fireplace has been outmoded by these more etficient central heating systems. However, the fireplace is still a popular feature in homes for its aesthetic qualities. These fireplaces burn fuel with combustion, air drawn into the fireplace from the room.

Such fireplaces actually place an added burden on the central heating system of the home because the room air drawn into the fireplace and vented up the chimney is replaced by outside air drawn into the home through cracks and openings about windows, doors, etc. In many cases, the cold air drawn into the home exceeds the useable heat output of the fireplace. Furthermore, rooms which are not heated by the fireplace chill quickly because of the cold air drawn through crevices and openrings in these rooms into the home to replace the air vented up the fireplace chimney.

This invention has as one of its primary objectives the provision of fireplace structure which alleviates the aforesaid conditions during fireplace usage. This is achieved by incorporating into the fireplace a structure or structures through which most or all of the air consumed by the fire and air drawn into the chimney with [flue gases is supplied through said structure or structures, which in turn are connected by suitable ductwork to an outside source of air.

These structures are preferably metal shell structures having metal walls of sufiicient strength to permit their being built in as a part of the firewall of the fireplace, in accordance with one type of embodiment of the invention. In another type of embodiment of the invention, the structures are made as a component part of a metal shell or shells of the type wherein cool room air is drawn into a lower part of the shell(s), heated therein by the hot shell surfaces, and discharged into the room as warmed 'all.

Another primary objective of this invention is to provide structures used in the construction of fireplaces to improve the elficiency of fireplace operation by supplying air to one or more openings in the firewall of the fireplace through air supply passages having a wall in the firewall of the fireplace so that cold, outside air is warmed by the heat of combustion in the fireplace before reaching the combustion Zone.

This objective is achieved by utilizing a structure or heater-type fireplace embodying in its metal shell structure a combustion air-supply unit for the fireplace.

FIG. 2 is a cross-sectional view of the embodiment of FIG. 1 taken on section 22 of FIG. 1.

FIG. 3 is an enlarged, cross-sectional view of the lower fragment of embodiment of FIG 1 taken on section 33 of FIG. 2.

FIG. 4 is an enlarged, cross-sectional view taken on section 4-4 of FIG. 3.

:FIG. 5 is a cross-sectional view ofthe embodiment of FIG. 1 taken on section 55 of FIG. 2.

FIG. 6 is a rear perspective view with a fragment of the rear wall broken awayof the embodiment of FIG. 1.

FIG. 7 is a cross-sectional view of a fireplace showing another embodiment of the invention with a portion of the structure broken away to facilitate illustration of the embodiment. 2

Referring first to FIGS. l-6, the fireplace 1 comprises a hearth 2, facework 3 and mantle 4 of any desired, suitable construction and materials. The firechamber of the fireplace is a three-sided, open front enclosure com-prising metal walls 5, 6 and 7. These metal walls are a part of a prefabricated metal shell adapted to be set in place in a building structure provided for it. The front part of the firechamber of the prefabricated metal shell has metal top wall 8 bridging the walls 5 and 7. The rear portion of the firechamber has a flue 9 made from a'metal, front flue wall 10 attached to or integral with the top wall 8, a pair of side flue walls 11,12 which are integral with or attach-ed to the rear portionsof the firechamber side walls 5, 7, respectively, and a rear structures having a metal wall of an air passage or passages built into the firewall of the fireplace so that the metal wall becomes heated by the fire and warms air passing therethrough.

A still further objective of the invention is to provide metal shell, fireplace air-supply structures which can be readily built into the firewall of a fireplace, be it a fire- Ibrick wall or a prefabricated metal firewall.

These and other objectives and advantages of the invention inherent therein or hereinafter described may be achieved by practice of the invention in accordance with the illustrated embodiments thereof in the accompanying drawings wherein: i

. FIG. 1 is a perspective view-of anair-conduction,

'erals have been used to designate like parts.

line Wall 13 integral with the rear wall 6 of the tire: chamber.

The sides of the prefabricated metal shell have hollow chambers 14, 15. Hollow chamber 14 is defined by side wall 5, an opposing, metal wall 1 6, a rear wall 17 which is an extension of fire chamber rear wall 6, a front wall 18, a bottom wall 19 spaced above the bottom of the metal shell unit, and a top wall 20. These walls are formed and attached together in any suitable manner so as to form the hollow chamber .14. a l

The hollow chamber 14 has ou-twardly directed duct members 21 and 22 adjacent the bottom and top of chamber 14. These duct members extend through a side wall of the fireplace facework and open into the room. The openings in the fireplace face work may be covered by grillwork 2 3 such as shown in FIG 1. These ducts allow room air to circulate through the hollow chamber 14 by convection, the air therein being heated by the wall(s) of the chamber which in turn is heated by the fire in the combustion chamber. Room air is drawn into the chamber 14 through the lower duct 21, and the warmed air is discharged through upper duct 22.

The chamber 15 is constructed similarly to the chamber 14 on the opposite side of the firechamber and like num- The structures of the heating chambers 14, 15 herein disclosed are shown primarily for purposes of illustration. The convection principle for heating room air by fireplace fires is well known, and any structure utilizing these principles may be used in the practice of the invention in lieu of the illustrated structure for the hollow chambers 14, 15. Other structures which may be used in the practice of the invention may be found, for example, in

'U.S. Patent Nos. 2,080,323; 2,494,527; 2,705,488;

'turcated air passagestructure for conducting combustionsupporting air to the firechamber. This bifurcated strucis ture is located in the lower or bottom portion of the metal shell structure so that the combustion-supporting air is supplied to the firechamber adjacent the chamber floor and is drawn into the fire zone by the draft of the fireplace.

This feature of the invention comprises, in the embodiment of FIGS. 16, a hollow, metal wall duct 25 extending across the bottom of the rear wall 6 on the rear face thereof. The duct 25 is formed by walls 26, 27 and 28 and the rear face of the lower portion of the rear wall 6 of the firechamber. The ends of the duct 25 are closed by plate segments 29 which project rearwardly from the lower, rear edges of the plates 16. Two air passages 30, 31 connect to and project forwardly from the duct 25. Each passage 36, 31 is formed by a bottom wall 32, the lower portions of firewall or 7 and the lower portion of the outer side wall 16 of the shell, and the wall 19. The walls 19 are divider walls dividing passages 30, 31 from chambers 14, 15, respectively. p

The metal shell of FIGS. 1-6 is constructed for use in a chimney structure located on an outside wall of the building. The supply of outside air to passages 25, 30 and 31 is through a short duct 33 communicating with and extending rearwardly from passage 25 a distance sufficient to extend through the chimney so that its opening 34 is approximately at the outer face of the chimney. The opening 34 may be covered by a grille 35 or a damper or shutter if the latter are desired. I

There should be in the combustion air supply system one or more dampers, valves, shutters or the like to stop drafts through the air supply system when the fireplace is not in use. A convenient place for such closure structure is at the outlet of the air supply passage on the firechamber wall(s).

As an example thereof, there is shown in FIGS. l-6 a pair of closures over the openings 36, 37 of passages 3t 31. A plate 38 having vertical slots 3? is attached to each of firechamber walls 5, 7. Between the rear face of plate 38 and a pair of angle irons 4t], 41 attached to walls 32, 19 is slidably mounted a closure plate 42 having vertical slots 43 corresponding to slots 39. A handle 44 is attached by pin 45 to the plate 42. The pin 45 is slidable in a horizontal slot 46 of a guide plate 47 attached to the front face of plate 38. The handle 44 is used to slide plate 42 to position slots 39 and 43 in the desired alignment or nonalignment to admit the desired amount of draft air for the fireplace or to close oi? the fireplace air supply when it is not in use.

The duct 25, its bifurcated passages 30, 31, their closure structure and the duct 33 may be used without the remaining structure of FIGS. l-6 in constructing a fireplace of the invention without a convection air-heating feature. In such case, the ductwork comprising memers 25, 3t 31 and 33 can be made of metal sheeting of sufiicient strength so that it will support the usual firebrick wall of the firechamber of a fireplace, which firebrick wall is built on top of duct 25 and passages 30, 31 so that the latter become the lower part of the firebrick firewall of the fireplace. Also, where room permits, the duct 25 and passages 30, 31 may be located entirely behind the firebrick firewall of the fireplace with appropriate, inwardly-directed ductwork to provide openings in the firebrick sidewalls or" the combustion chamber equivalent to the openings 43 in the illustrated embodiment.

For fireplaces on inside walls of buildings, the duct 33 may be directed downwardly and may be connected to additional ductwork beneath the subfiooring of the building. The latter ductwork in turn extends through a wall of the building or its foundation to connect the duct 25 and its associated passages 30, 31 to a source of air outside the building.

FIG. 7 shows another form of the invention in which the combustion air supply unit is built into the firebrick firewall of the fireplace. The fireplace is of the usual construction-having a combustion chamber comprising a firebrick side wall 50, a firebrick rear wall 51, and a second firebrick side wall (not shown). The combustion air supply unit in this case is a rectangular, heavy wall metal box 52 which is built into the firebrick wall 50. The metal box has a pair of side walls 53, a rear wall 54, a top wall 55 and a bottom wall 56. The front wall of the box 52 is covered with a removable cover plate 57 having vertical slots 58.

Cover plate 57 carries a slidable plate by which the slots 58 can be closed off in the same manner as described with respect to slots 39 of plate 38 of the embodiment of FIGS. l-6. Hence, the details of this structure will not be repeated.

The opposite side wall (not shown) of the fireplace should also have a metal box 52 and associated parts to provide a balanced air fiow to the combustion chamber. Each box 52 is supplied with outside air by a vertical duct 59' opening into the bottom wall 56 of the metal box. Duct(s) 59 is connected by suitable ductwork 60 beneath the building floor 61 and terminates at an outside wall of the building. In some instances, e.g., homes with an unheated foundation crawl space, unheated, ventilated basements, etc., the ductwork may terminate in these areas.

It is to the best advantage in the practice of the invention to supply the combustion air to the combustion chamber through both side walls of the firechamber with the air openings in the side walls being toward the open front of the fireplace. Under these arrangements, an even, easy draft of combustion air is supplied to the fireplace With little induction into the fireplace of room air. Cold air is no longer drawn into the house through cracks and crevices, and the over-all effect is a better performance of the fireplace and a lesser load on the central heating system of the home. In fact, with a combustion air supply system of the invention, the open front of the fireplace may have a glass front or panel to completely separate the room from the firechamber. Especially in cases where the air supply ductwork is so small that duct resistance to air flow through the supply passages and ducts is inadequate under the normal draw of the fireplace, a blower B may be incorporated in the air supply ductwork to assure an adequate supply of combustion air to the combustion chamber. 7

, There are many embodiments of fireplace structure in which the principles of the invention may be practiced. Furthermore, even in the specific embodiments shown and described heretofore, structural changes or additions may be made without departing from the spirit and scope of the invention. For example, While it is preferred that the opening(s) communicating the firechamber and the combustion-supporting air passage(s) be in the forward portion of the side wall(s), they may be in the middle or rear portion of the side wall(s) or even in the rear wall of the firechamber.

The invention is hereby claimed as follows:

1. A metal fireplace structure comprising a firechamber including a vertical metal rear wall and two forwardly-extending, vertical metal side walls, metal wall structure defining with each side wall a hollow chamber on each of said side walls of said firechamber, a horizontal divider wall in each hollow chamber dividing each chamber into separate, upper and lower hollow chamber segments, each upper segment having an air-entry opening in its lower part and an air-exit opening in its upper part whereby room air may circulate by convection through said upper segment, each lower segment defining a forwardly-extending air supply passage extending along the lower portion of the respective side wall, additional metal wall structure defining with the lower portion of said rear wall a horizontal, air supply passage extending across the lower portion of said rear wall, the opposite ends of said last-mentioned air supply passage being open and in communication with the respective air supply passages of said lower segments, the lower, forward corner of each of said side walls having an opening therein communicating the forward portion of the respective forwardly-extending passage with the firechamber of said fireplace, closure means at said openings adapted to close said openings when the fireplace is not in use, and duct means communicating with said horizontal air supply passage for supplying to said firechamber through said horizontal passage and said forwardly-extending passages combustion-supporting air drawn from a source outside the room in which said fireplace is located.

2. A fireplace structure as claimed in claim 1 wherein said duct means is a horizontal, rearwardly-extending duct connected to and communicating with the mid-portion of the rear Wall of said horizontal passage.

3. A fireplace structure as claimed in claim 1 wherein said closure means comprises a slotted plate fixedlymounted across each of said openings, a slotted closure plate on a face of each of said fixedly-mounted slotted plates, and means holding each of said closure plates for movement relative to said fixedly mounted plates to align References Cited by the Examiner UNITED STATES PATENTS 737,382 8/03 Frederick 126-131 1,196,766 9/16 Elkin 126121 1,250,712 12/17 Thorne 126-120 1,430,781 10/22 Ackroyd 126--120 2,103,171 12/37 Nilson 126--120 2,497,486 2/50 Barber 126-120 2,725,874 12/55 Payne 126121 2,970,590 2/61 Fauser 126121 JAMES W. WESTHAVER, Primary Examiner.

PERCY L. PATRICK, Examiner.

Claims (1)

1. A METAL FIREPLACE STRUCTURE COMPRISING A FIRECHAMBER INCLUDING A VERTICAL METAL REAR WALL AND TWO FORWARDLY-EXTENDING, VERTICAL METAL SIDE WALLS, METAL WALL STRUCTURE DEFINING WITH EACH SIDE WALL OF HOLLOW CHAMBER ON EACH OF SAID SIDE WALLS OF SAID FIRECHAMBER, A HORIZONTAL DIVIDER WALL IN EACH HOLLOW CHAMBER DIVIDING EACH CHAMBER INTO SEPARATE, UPPER AND LOWER HOLLOW CHAMBER SEGMENTS, EACH UPPER SEGMENT HAVING AN AIR-ENTRY OPENING IN ITS LOWER PART AND AN AIR-EXIT OPENING IN ITS UPPER PART WHEREBY ROOM AIR MAY CIRCULATE BY CONVECTION THROGUH SAID UPPER SEGMENT, EACH LOWER SEGMENT DEFINING A FORWARDLY-EXTENDING AIR SUPPLY PASSAGE EXTENDING ALONG THE LOWER PORTION OF THE RESPECTIVE SIDE WALL, ADDITIONAL METAL WALL STRUCTURE DEFINING WITH THE LOWER PORTION OF SAID REAR WALL HORIZONTAL, AIR SUPPLY PASSAGE EXTENDING ACROSS THE LOWER PORTION OF SAID REAR WALL, THE OPPOSITE ENDS OF SAID LAST-MENTIONNED AIR SUPPLY PASSAGE BEING OPEN AND IN COMMUNICATION WITH THE RESPECTIVE AIR SUPPLY PASSAGES OF SAID LOWER SEGMENTS, THE LOWER, FORWARD CORNER OF EACH OF SAID SIDE WALLS HAVING AN OPENING THEREIN COMMUNICATING THE FORWARD PORTION OF THE RESPECTIVE FORWARDLY-EXTENDING PASSAGE WITH THE FIRECHAMBER OF SAID FIREPLACE, CLOSURE MEANS AT SAID OPENINGS ADAPTED TO CLOSE SAID OPENINGS WHEN THE FIREPLACE IS NOT IN USE, AND DUCT MEANS COMMUNICATING WITH SAID HORIZONTAL AIR SUPPLY PASSAGE FOR SUPPLYING SAID FIRECHAMBER THROUGH SAID HORIZONTAL PASSAGE AND SAID FORWARDLY-EXTENDING PASSAGES COMBUSTION-SUPPORTING AIR DRAWN FROM A SOURCE OUTSIDE THE ROOM IN WHICH SAID FIREPLACE IS LOCATED.

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