CA1132870A

CA1132870A - High efficiency fireplace modification

Info

Publication number: CA1132870A
Application number: CA379,052A
Authority: CA
Inventors: Harold Aidla
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-06-04
Filing date: 1981-06-04
Publication date: 1982-10-05

Abstract

ABSTRACT OF THE DISCLOSURE
A fireplace extension is provided, which extends forwardly from a traditional fireplace, having two sets of doors, a first set of doors within the extension, and a second set of doors which close the extension. Fresh air duct means open into the fireplace extension between the first and second set of doors, and damper means are pro-vided in the first set of doors, whereby, a surprising increase in efficiency in the fireplace itself is achieved, not only from the point of view of heat generated, but from the duration of time during which such fireplace is effective in generating heat.

Description

~13Z8~0 This invention relates to a modification -to standard fire-places of the type having heat reclaiming systems known under such trade marks as HEATILATOR and the like.
The invention provides a fireplace structure which permits both higher heat output plus greatly extended burn times.
The invention is specifically directed to an extension projecting forwardly from a standard fireplace already equipped with warm air circulating apparatus as is well known to those skilled in the art.
The structure described hereinafter is adapted for easy installation to an existing fireplace, at relatively low cost.
The fireplace modification described herein may be finished with brick identical to or complementing the brick used in the fire-place itself, and thus be visually unobtrusive, and, in fact, attrac-tive.
A principal object of the invention is to provide an exten-; sion extending unitarily forwardly of a fireplace comprising a pair ; of side walls and a top and bottom; a first set of doors within said extension; a second set of doors adapted to close said extension; a fresh air duct means opening into said extension between said firstand second set of doors; and damper means in said first set of doors.
Reference will be made to the accompanying drawings in which:
Figure 1 is a perspective view of the fireplace addition with portions broken away; and Figure 2 is a top plan of the fireplace addition according to the invention, with elements omitted for purposes of simplicity.
Detailed reference will now be made to the drawings, wherein like reference numerals will identify like parts.
An existing fireplace 10 has a fireplace opening 12, fire-place lO being provided with heat reclaiming apparatus, not illustrated~

, 1~32870 and is modified by at-taching thereto a rectangular, metal U-shaped frame member 14 surrounding the top and both sides and bottom of fire-place opening 12, as shown in Figure 1. A brick enclosure is partly illustrated in Figure 1, comprising a side wall 16, and a facing side wall 18 is illustrated in Figure 2. The extension is also provided with a top, not illustrated for purposes of simplicity.
A pair of innter doors 20 are hingedly mounted on frame 14 and are adapted effectively to close fireplace opening 12, doors 20 being double-walled, and as seen most clearly in Figure 2 an inner panel 20a is spaced apart from the outer panel of door 20, by spacer and retainer nuts and bolts 20b.
Damper 22 in door 20 is seen in Figure 1. A plurality of air holes 24 are provided on inner door panels 20a, whereby air flow into the fireplace opening 12 may be selectively controlled.
A fresh air inlet 26 is provided immediately in front of fireplace opening 12, and it will be appreciated that when doors 20 are securely closed, as by means of locking handle 28, that fresh air available from duct inlet 26 will be drawn through dampers 22 to the fireplace opening.
Outer doors 30, which as illustrated may include transparent panels, are adapted to completely seal the extension created by wall 16, 18, and the top thereof. The provision of transparent panels in outer doors 30 will permit viewing of a fire within fireplace opening 12, when desired, by leaving inner doors 20 in the open position illustrated in Figure 1.
In operating a fireplace modified according to the invention described herein, some experimentation will be required on the part of the user, in order to determine the extent to which dampers 22 should be open. After short experimentation, however, it will be found that the efficiency of the fireplace modified as described will be .

dramatically increased.
Using equal quantities oE identical fuel, it has been found that not only has the quantity of heat generated, but the duration of a fire has been improved as illustrated in the accompanying table.
In taking heat measurements, to obtain the results shown hereinafter, the fire box was pre-heated to 300F. by burning small kindling. The fire was built by placing two six and a half inch diameter 16 inch long birch logs into the fire opening where tempera-ture readings were taken every 15 minutes at the fire box, the chimney, and the heat reclaimer outlets.
The results of these burns are shown in the following table.

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~4 ~ C) -4b-113Z8~'0 It will be seen tha-t with both of -the fireplace extension doors closed a drama-tic increase in temperature outpu-t and in duration of burn were achieved. It is significant that the duration of the burn achieved with both se-ts of doors closed ex-tended the useful heat output by one and three quarters (1-3/4) of an hour, with heat produced through the fireplace firebox ductwork being at significantly higher temperatures than the output when only the inner doors were closed.
It is not possible -to explain all of the reasons for the dramatic improvement in fireplace efficiency using the modification described herein. Part of the reason is obviously because of air pre-heating within the extension, as fresh air flows from vent 26, and then through damper 20, to within the space between interior door panels 20 and 20a, before entering the fireplace opening. This explanation in itself does not account for the very significant improvement in the fireplace performance.
It will be evident to those skilled in the art that the relatively low cost of an extension to a standard fireplace as described in the light of increasing fuel costs and the results achieved represent a significant advance in the fireplace art.
The structure described herein is by way of example and it will be evident that, for example, the bricks illustrated may be replaced by other building materials, and -the invention should be limited only by the scope of the appended claims.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a fireplace, an extension extending unitarily forwardly thereof comprising a pair of side walls and a top and bottom;
a first set of doors within said extension;
a second set of doors adapted to close said extension;
a fresh air duct means opening into said extension between said first and second sets of doors;
and damper means in said first set of doors.

2. In a fireplace extension according to claim 1, said set of doors within said extension each having a pair of spaced-apart panels whereby air flowing through said damper means is pre-heated.

3. A fireplace extension comprising:
a unitary box-like extension projecting forwardly from said fireplace, having hingedly mounted doors at the front thereof, and a second pair of doors within said extension adapted to close said extension;
fresh air duct means communicating with the interior of said box-like extension.