Air intake system for enclosed freestanding fireplace

An improved air intake system for a freestanding fireplace of the type having a tubular base secured to a floor support, a firepot mounted on the base, a substantially cylindrical firepot enclosure, and a conical hood having an internally mounted, upwardly spiraling, flange. The improvement includes an air conduit connecting the tubular base to an outside air source located below the floor support and a second conduit extending between the tubular base and the firepot enclosure, the second conduit terminating adjacent one edge of the firepot in a substantially horizontal direction to impart a circular motion to exiting air. Another conduit extending between the tubular base and the firepot enclosure, terminating adjacent an oppositely disposed edge of the firepot from the second conduit and terminating in a substantially horizontal direction opposite to that of the second conduit may be included. The improvement may also include dampers within the conduits extending from the tubular base to the firepot enclosure for controlling air flow; a screen covering the opening of the first conduit to prevent admittance of rodents; and a filter to prevent dusk intake. A doorway into the tubular base for cleaning or replacement of screens and filters may also be included.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates, in general, to freestanding fireplaces, and in 
particular, to air intake systems for freestanding fireplaces having an 
enclosed combustion chamber. 
2. Description of the Prior Art 
Primarily because of their structural arrangement and because of their 
ornamental characteristics, free standing fireplaces have seldom been 
provided with energy saving devices. The combustion chambers of free 
standing fireplaces are generally characterized by having large 
nonclosable openings which result in a noncontrollable draft which draws 
large amounts of heated air from the room. Heat conduction is largely 
limited to the smooth interior walls of the hood. 
BRIEF SUMMARY OF THE INVENTION 
The present invention comprises an improvement to the freestanding 
fireplace described in my co-pending application; ie., a freestanding 
fireplace having a base, a firepot mounted on the base, a firepot housing 
ring encircling the firepot, a substantially cylindrical combustion 
chamber mounted on the housing, and a conical hood mounted on the 
combustion chamber. The hood contains a substantially horizontally 
projecting, upwardly spiraling, flange mounted on the interior wall for 
imparting a circular motion to the combustion fumes. The improvement 
includes an air conduit extending between a tubular base and an external 
air source located below the floor support; an additional pair of conduits 
extending between the tubular base and the firepot enclosure and 
terminating at oppositely disposed locations adjacent the firepot in a 
substantially horizontal direction so as to impart a circular motion to 
the incoming air; a damper located with these additional air conduits for 
controlling air flow; a screen and filter; and a door openable into the 
tubular base for removal and replacement of screens and filters. 
It is therefore a general object of the present invention to provide an 
enclosed free standing fireplace having an external air source. 
It is a further object of the present invention to provide a freestanding 
fireplace having an external air source which includes oppositely disposed 
air intake vents having their openings in opposite directions for 
imparting a circular motion to air to facilitate burning. 
It is another object of the present invention to provide a freestanding 
fireplace having an external air source which includes a screen and filter 
and means in the base portion for removing and replacing the screen and 
filter. 
Additional objects and advantages will become apparent and a more thorough 
and comprehensive understanding may be had from the following description 
taken in conjunction with the accompanying drawings forming a part of this 
specification.

DETAILED DESCRIPTION OF THE INVENTION 
Referring now to the drawings, and, more particularly, to FIG. 1, an 
embodiment to be preferred of a freestanding fireplace 10, made according 
to the present invention is disclosed. Freestanding fireplace 10 includes 
a base 5, a firepot housing ring 27, a firepot 25, a combustion chamber 
30, and a conical hood 40. 
Base 5 is tubular in construction, having a hollow interior and a 
cylindrical side wall 4. Base 5 may include annular flange 3 welded 
transversely to wall 4. The flange may be attached to floor 2 by bolts, 
screws, or the like. Base 5 is formed with a side opening, not shown, and 
a closure, door 7, which is hingably attached to side wall 4. Base 5 is 
placed over and surrounds air conduit 51 which vertically extends through 
an aperture in floor 2. The distal end of air conduit 51 may terminate 
just below the bottom surface of floor 2, as in mobile homes and other 
homes having air venting under floor 2, or may terminate by means of a 
tubular extension through the vertical foundation of a home, it only being 
essential that conduit 51 terminate to an external air source. Air conduit 
51 includes, preferably, at its proximal end which terminates within the 
interior of base 5, a screen 81 for preventing the entrance of insects, 
rodents, and the like. Screen 81 is annular in form and may be of any 
suitably sized mesh. The screen may be placed upon horizontally extending 
shoulders 82 located on the interior of tube 51 for easy removal and 
cleaning. Located proximal to screen 81, within conduit 51, is an air 
filter 91, preferably capping the conduit. Filter 91 prevents the intake 
of dust and other fine particles into base 5 and therefore into combustion 
chamber 30. It is to be noted that both the screen and filter are easily 
removed through the opening in sidewall 4 of base 5. 
Firepot 25 is conical in shape having an outer shell structure 24. In 
place, the cone shaped fire pot has its apex pointed downwardly and 
centered within base 5. Shell 24 is filled with a fire proof composition 
containing preferably three parts fire clay, one part sand, and one part 
cement. The composition is placed in the shell, filling the shell to the 
top of vertical side walls 23, and is then smoothed out so that it too is 
conical in configuration. Firepot 25 is securely mounted to base 5 by 
welding or otherwise. The preferred composition gives the firepot strength 
and hardness, and keeps the outer part of shell 24 from getting hot, 
thereby eliminating any fire hazard to close by objects or the floor. 
Firepot housing ring 27 is a flat annular ring mounted horizontally flush 
on the top lip of wall 23 of firepot 25. Ring 27 supports combustion 
chamber 30 as will hereinafter be described and also contains apertures 
for air conduits 21. In the preferred embodiment, fireplace 10 includes 
two air conduits, at one end connected to and opening into the interior of 
base 5 and at the other end opening into combustion chamber 30 through 
ring 27 at an angle preferably less than 45.degree. to horizontal. The 
points of entrance through ring 27 of the two conduits 21 are oppositely 
disposed adjacent firepot 25 and have their openings facing in directions 
opposite to one another so as to provide a circular motion to air entering 
the combustion chamber through the conduits. In this regard, conduits 21 
may approach ring 27 at a substantially horizontal angle or baffles 21' 
may be used to accomplish the result. Baffles 21' may simply be an 
extension of conduits 21. Conduits 21 may each contain a conventional 
butterfly damper 61 for controlling air flow to the combustion chamber. 
Combustion chamber 30 may be substantially cylindrical in configuration. 
The chamber is octagonal in the preferred embodiment containing a 
plurality of metallic vertical supports 32, each of which ecases and holds 
in place tempered glass panels 34. The entire structure is securely 
mounted vertically on ring 27. Chamber 30 also includes a tempered glass 
door 38 which sealingly closes the combustion chamber when closed, and 
when open, provides entrance to the firepot for the placement of 
combustible materials and for the removal of ashes. 
A second flat horizontal ring 47 is mounted horizontally on and secured to 
the top most terminal ends of vertical supports 32. Upper ring 47 serves 
to hold vertical supports 32 in place and also serves as a base support 
for hood 40. Hood 40, of conventional conical formation, is provided with 
a flue vent 49 which is centrally mounted adjacent the apex of the 
cone-shaped hood. Mounted on the interior wall 42 of hood 40 is a 
horizontally oriented, upwardly spiraling flange 45 extending from 
substantially the lowermost portion of the hood to the uppermost portion 
of the hood adjacent flue vent 49. Flange 45 may spiral upward in either a 
clockwise or counter clockwise direction, it only being necessary that it 
spiral upward in the same direction as the openings of conduits 21. An 
annular damper plate 43 may be installed, preferably adjacent the base of 
conical hood 40 between opposing portions of the flange. 
In operation, combustible material is either piped into the firepot 25 or 
placed in firepot 25 through door 38, and ignited. Damper controls 61 are 
set at a selected setting to allow a desired amount of air flow into the 
combustion chamber 30 in communication with firepot 25. As the air is 
heated within combustion chamber 30, air will be pulled through the distal 
end of air conduit 51, through screen 81 and filter 91, into base 5 and 
through conduits 21 into combustion chamber 30. With air conduits 21 
opening into the combustion chamber at opposite angles, it will be seen 
that a circular draft is created. The air and fumes of combustion moving 
in a circular motion are pulled upwardly into hood 40 by the draft. Damper 
plate 43 prevents a purely vertical motion to the air, forcing the air to 
continue in its upward spiral along the bottom most edges of flange 45. In 
this manner the upward draft is slowed allowing the extending flange 45 to 
absorb a large portion of the heat from the heated air and fumes. Flange 
45, being metallic and in direct conductive union with hood wall 42, also 
metallic, allows a large percentage of the heat thus absorbed to be 
radiated from the exterior wall 42 of hood 40 into the surrounding air. 
The smoke and fumes then pass through air vent 49 which is connected to a 
chimney or other venting device. 
Having thus described in detail a preferred embodiment of the present 
invention, it is to be appreciated and will be apparent to those skilled 
in the art that many physical changes could be made in the apparatus 
without altering the inventive concepts and principles embodied therein. 
The present embodiment is therefore to be considered in all respects as 
illustrative and not restrictive, the scope of the invention being 
indicated by the appended claims rather than by the foregoing description, 
and all changes which come within the meaning and range of equivalency of 
the claims are therefore to be embraced therein.