US2158041A - Fireplace - Google Patents

Description

1939- J. D. COVERT 2,158,041

FIREPLACE Filed July 9, 1936 2 Sheets-Sheet 1 IN VENTOR.

y 1939- J. D. COVERT 2,158,041

FIREPLACE Filed July 9, 1956 2 Sheets-Sheet 2 I MWKWL TTORNEY.

Patented May 9, 1939 UNITED STATES smear OFFICE 5 Claims.

This invention relates to the art of fireplace heating, and is particularly concerned with the provision of a fireplace which is adapted to give off heat by convection as well as by radiation, and which is arranged to supply heated air from without the room in order most efficiently to heat it. The novel fireplace is simple in design, inexpensive of manufacture, easy of installation and attractive in appearance, and utilizes to the fullest practicable extent the heat given out by the fuel which is burned in the space provided for that purpose.

This application is a continuation in part of my copending application, Ser. No. 731,818, filed .June 22, 1934.

While it has heretofore been proposed to provide fireplace heating devices for heating air and circulating it through the room, such devices have been relatively complex in nature and, therefore, expensive and impracticable, or else they have been so designed as to lack the eflici-ent operation required to ensure their ready reception. The present invention is designed to overcome these fundamental difiiculties.

Another object of this invention is to provide a ready-made heating unit for fireplaces which may be readily incorporated in the chimney of a domestic or other structure, and which utilizes the heat of combustion to the fullest practicable extent.

Another object is to provide a construction by means of which the room to be heated is ventilated by utilizing the suction created by the fire to draw heated air into the room from without the room and thus to prevent cold air from being only directed into the room, but is also carried indirectly into the air stream which flows through the device of the invention.

Another object is to provide an efiicient heating unit which after installation is so thoroughly concealed within the masonry of the fireplace that its presence is apparent only to an expert.

A further object is to provide a heating unit of good heat-conducting material constructed integrally and provided with simple standard con- '"nections to lead the heated air into the room,

the whole of which may be very economically manufactured and installed.

A still further object is to provide for the 'expansion of such metal parts of the unit as are subjected to the greatest temperatures, and thus to prevent the buckling of the metal or cracking of the masonry and the consequent disfiguration of the mantel face resulting from leakage of smoke and combustions gases.

A still further object is to provide a scientifically designed form about which the masonry of the fireplace may be built, so that a properly proportioned fire chamber, throat, adjustable damper and smoke chamber is provided for the mason, and he is thus enabled to build a perfect fireplace.

Other objects and advantages of the invention will more clearly appear when reference is had to the following specification and accompanying drawings. 20

Briefly described, the invention comprises a ready-made integral metallic fireplace air-heating and circulating unit adapted to be installed in the masonry of the fireplace, with a channelled air-heating chamber sea-led from the combustion chamber, for directing the air across the hottest part of the back plate of the combustion chamber. The air supply and discharge connections with these channels are easily and economically constructed in the masonry without the use of expensive metal castings or piping, while maintaining a gas-tight passage throughout the air-conducting system.

In the drawings, Fig. 1 is a front elevation, with parts broken away, of a fireplace in which the present invention is utilized; Fig. 2 is a sectional view, also with parts broken away, taken along the line 2-2 of Fig. 1; Fig. 3 is a detailed section of the portion of the device adjacent the side of the masonry of the combustion chamber, showing means for forming a joint between the back plate of the fireplace and themasonry; Fig. 4 is a vertical section taken along line 4-4 of Fig. 1; Fig. 5 is a transverse section taken along line 55 of Fig. 1, showing the construction of the lower part of the air-heating chamber and the manner in which air is supplied thereto; and Fig. 6 is a detail, in section, showing how the air-egress openings are provided for easy and gas-tight connection with the egress piping.

The air-heating chamber proper is constructed of a back plate of heavy metal consisting of a lower vertical portion Ill and an upper portion II, which slants forwardly toward the front of the fireplace, side walls l2 and I3 and rear wall M. The air-heating chamber is designated as It] and is closed at the top by horizontal plate i6. Above this plate a smoke chamber 20 is formed forwardly of the rear wall M by means of wall H, which is inclined rearwardly and upwardly, and side Walls l8 and I9, which are inclined inwardly and upwardly; the upper portion of the respective wall members of the smoke chamber defining a substantially square opening 28 through which the smoke from the fireplace passes into the flue. I prefer to construct the masonry about the upper part of the smoke chamber so that a course of bricks 2| (Fig. 4) extends over the edge of the respective walls, so that the flue lining 22 can be readily set in place on their upper surfaces.

Integrally secured along the front wall I! of the smoke chamber is an apron member I1 extending downwardly and forming between the,

back plate II and the masonry on each side of the fireplace a flue or throat through which the combustion gases from the fire may pass to the smoke chamber 20. Adjacent this apron I1 may be provided an angle bar or arch iron 23 resting upon adjacent side walls of the masonry and extending across the opening of the fireplace to support the brickwork 24 over the fireplace opening.

Forwardly extending from the lower edge of the rear wall !4 are reenforcing straps or bars 25 and 26, the ends of which are upturned as at 2! and 28 and are united to the end portions of the apron member I1 These straps, as well as the associated parts of the heating unit previously described are made of metal, such as iron. or steel, and are integrally formed together, as by welding, in order to form a strong unitary structure. The member 23 need not, however, be connected to the heating unit itself; in fact, it is preferable to supply this member separately in order to allow the mason greater latitude in making the installation.

Pivoted at the forward edge of the plate i6 is a damper 3B, and secured to the upper end of back plate II, is a bracket 33. The damper is operated by an arm 32 pivoted on the bracket and connected to the damper by a link 3|. The arm 32 is preferably pivoted in such a manner that a considerable degree of friction between the bracket and the arm is maintained in order to enable the arm to be adjusted in any desired position. Thus the throat of the fireplace may be opened or closed according to the degree of draft desired to suit any given set of conditions.

In order to'provide for the ingress of air. the rear wall I is provided with an opening 34 designed with an area substantially the same as that or larger than that of the horizontal crosssection of the lower portion of the unit shown in Fig. 5. This permits connection with a supply of air by merely forming a passage 35 in the masonry at the rear, connecting outside the house, to an adjacent room or tothe room located on a lower floor.

The unit thus far described is simply set in place on the floor of the fireplace and bricks laid around it and over the straps 25, 26. This anchors theunit in place and conceals all of it save the back plate structure in. the firebrick.

The construction of the upper part of the air system will be seen in Figs. 1, i and At the upper portions of walls ii}, iii are provided openings 42, about which are welded egress members 3t, which may be in the form of heavy metal elbows, as shown in detail in Fig. 6. These extend upwardly to a point indicated approximately at 37, some distance above the level of plate It and are made of a diameter adapted to receive snugly the crimped end of a standard stove pipe elbow 38, to which are fitted straight lengths 39 and elbows 40 leading to grills 4| in the wall of the room. Only one side of the upper part of the system has been described in view of the fact that the other side is the same. These. conduits are built just prior to the completion of the masonry which is built around it in the manner indicated in Figs. 1, 2 and 4.

In order more fully to utilize the heat conducted to the back of the fire, flanges 45 are integrally formed with back plate It and extended up the rear face thereof in parallel arrangement, as indicated in Figs. 1, 2 and 4. These are preferably provided at the central portion of back plate H, which is the hottest part of the fireplace, since the flames come in direct contact with it over this area. The flanges, however, may be provided over the entire surface of back plate l l, and also to a more limited degree on the rear surface of back plate HI, which, as previously indicated, is integral with plate I i. These flanges 35 are very effective in conducting the heat absorbed by the back plates into the interior of the air-heating chamberlS, and they form channels A i, which tend to accelerate and guide the natural upward tendency of the heated air. This is enhanced by the air coming in contact with the hot back plate I l and mushrooming and expanding to an extent which causes it to drive outwardly and upwardly along the sides of the flanges and along the inside of the back plates, absorbing heat during its passage along this course. Moreover, the expansion of the heated air in, the confined spaces below the channels and within them accelerates its passage, causing a larger quantity to be forced through the exit openings 42 and into the ducts leading into the room, than would otherwise be the case.

In order to provide a space in which the cen tral portions of the unit may expand, flexible strips 45, such as tin, are secured to walls i2, is. These strips are arranged to contact the side Walls 41 of the masonry. They provide a guide for the mason and ensure the maintenance of proper distance between the masonry and the metal unit at the sides.

It should be noted that the air used in the system just described is drawn from a source without the room and thus furnishes ample supply of heated air to replace that taken up the flue by the suction of the fire. This results in a warming and ventilating of the entire room. If the air were not taken from without the room, the fireplace would either draw air down the chimney, or it would draw cold air through the cracks in the windows, doors, Walls or floors, since the system must be provided with air to replace that sucked up the chimney. It is obvious that the construction described avoids sucking in such cold air, ventilates the room with an ample supply of fresh warm air from an independent source lessens the likelihood of having the room entirely cold except in the immediate vicinity of the fire.

Due to the relatively shallow construction of the bottom part of chamber t5 the front-to-back dimension, or depth, being considerably less its height (see Figs. 4 and 5), the incoming air mushrooms out against the back plate It and simultaneously expands in this chamber while it is drawn upwardly by the natural suction of the previously heated rising air. This draws the air into channels 44 where it is further heated and expanded and given an added upward impetus. The result is that a large volume of hot air moving at high velocity is driven through the grills and into the room, where it circulates over the upper portion of the room, driving the cooler air downwardly to the floor, where it is sucked into the fire and up the flue. This heats the room with surprising efficiency.

The structure described is extremely simple and may be installed by the mason employed to build the fireplace. Instead of providing large quantities of metal of complex arrangement, a relatively small proportion of metal is required. This is so arranged that it absorbs heat only from the greatest heat-giving area at the rear of the fireplace, which it does with marked eificiency. This considerably reduces the amount of metal and metal-working required for the manufacture of the unit, simplifies the construction and reduces the cost to the user. The sides of the fireplace are lined with firebrick, and the unit is thus concealed entirely, except for the back plates, which soon become blacked and made indistinguishable, so that the fireplace has a natural appearance. The metal straps anchor the unit securely into the masonry. The entire unit, including the combustion chamber, throat, smoke chamber and flue base are preconstructed and scientifically designed so that the mason has an exact form which will permit him to make no errors in construction.

The suction of the air system has a strong tendency to draw combustion gases through the smallest crack in the masonry construction. For this reason the upwardly-extended portion of the steel elbow 36 forces the mason to place the hot air pipe connection to the grill outlets 4|, well away from the vicinity of the combustion chamber, and by this means the combustion gases and smoke are prevented from being drawn into and contaminating the air circulatory system.

Having thus described my invention, what I claim is:

1. A fireplace air-heating unit, comprising a metallic back plate extending upwardly from a hearth and forming the back of the combustion space, an air-heating chamber disposed to the rear of said back plate and formed by metallic side and rear walls integrally connected together and to said back plate, an air-ingress opening in the rear wall of said chamber, a top plate sealing the top of said chamber, a smoke chamber disposed above said top plate and formed by upwardlyand inwardly-inclined metallic walls integral with the walls of said air-heating chamber, an apron integral with a wall of said smoke chamber and extending parallel with said back plate and with the top of said back plate defining a throat for the passage of combustion gases from the combustion space to said smoke chamber, said apron being supported by metal straps extending downwardly to the hearth and rearwardly to the rear wall of the air-heating chamber; said straps being integrally formed with the connecting members, air-egress openings in the side walls of said air-heating chamber connected. to integrally-formed metallic members, and heat-conducting flanges integrally secured to said back plate within said air-heating chamber.

2. A fireplace air-heating device, comprising a metallic back plate forming a part of a unitary metallic casing comprising an air-heating chamber disposed to the rear of said plate and upon the hearth of the fireplace and having an airingress opening therein, a smoke chamber disposed within said casing above said air-heating chamber, an apron disposed forwardly of said back plate and defining with the forward uppermost edge of said back plate a throat communieating with said smoke chamber, supporting straps for said apron; said apron being integrally connected to said casing and to said straps, which rest on the hearth and connect to a wall of said air-heating chamber, air-egress openings in said casing, and heat-conducting flanges extending into said air-heating chamber and integrally formed with said back plate.

3. A fireplace heating device, comprising a unitary metallic casing disposed wholly at the rear of said fireplace on the hearth thereof and anchoredi in the masonry comprising the walls thereof, said casing having an air-heating chamber sealed from the combustion space of the fireplace, and a smoke chamber communicating by a throat to said combustion space, said air-heating chamber having an air-ingress opening at the lower part thereof and air-egress openings formed at the upper part thereof, said openings being adapted to communicate with air ducts built in the masonry of the fireplace, said airheating chamber having disposed within it a plurality of heat-conducting members integrally secured to that wall of said chamber constituting the back plate of the fireplace and the front plate of the air-heating chamber.

4. A fireplace heating device, comprising a unitary metallic casing disposed wholly at the rear of said fireplace on the hearth thereof and anchored in the masonry comprising the walls thereof; said casing having an air-heating chamber sealed from the combustion space of the fireplace, and a smoke chamber communicating by a throat to said combustion space; said air-heating chamber having openings adapted to connect with air ducts built in the masonry of the fireplace, andhaving a relatively shallow bottom portion. co-operating with a plurality of air-accelerating channels formed by metallic flanges integrally secured to the side of the casing constituting the back plate of the fireplace.

5. A fireplace air-heating unit, comprising an integral casing disposed wholly to the rear of the combustion chamber of the fireplace, said casing having one side constituting the back plate of the fireplace and having a lower chamber comprehending a relatively restricted space disposed immediately below said side which is provided with heat-conducting flanges integrally constructed therewith and extended into said casing.

JAMES D. COVERT.

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