Method and apparatus for improvements in convective heating
OwnerJoseph Henriquesinventor
Life of this patent
Estimating the term…
Abstract
The efficiency of a convective heating system employing an elongate firebox is dramatically increased by, inter alia, increasing combustion zone volume to approach that of the firebox and increasing residence time of rising combustibles at ignition temperatures.
Claims29
An improved convective heating system of the type having fireplace enclosure walls, a chimney with an apertured fireplace pan (74) for receipt of nascent products of combustion, and an elongate firebox (10) having bottom (12), top (14), back (16) and side walls (18) positioned in spaced relation to the corresponding fireplace enclosure walls and defining therewith a convective flow path of air across said firebox walls, said firebox having a front wall with a fuel receiving opening and a hearth area rearwardly of said front wall, the walls of the firebox defining an elongate volume of space within the firebox, the improvement comprising:
- (A) means, connected to the firebox, for maintaining an ignition temperature range substantially throughout that elongate volume of said firebox overlying said hearth area, said means including a flue assembly (20) having a flue extension (24) passing downwardly through the top wall of the firebox into the firebox with an opening (22) for receipt of nascent combustion products, the flue extension extending below the top wall of the firebox so as to create a blanket of hot combustion products (44) adjacent the firebox top wall, the flue assembly having a flue pipe (78) connected at one end to the outlet end of the flue extension and at its other end to the apertured fireplace pan (74) of the chimney for allowing the combustion products to pass up the chimney while preventing the convective flow path of air from passing up the chimney;
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- (B) combustion air inlet means including a preheat manifold (28) mounted within the firebox and extending between the side walls of the firebox, the preheat manifold having at least one opening (50) at one end extending through the corresponding firebox side wall for receipt of combustion air and also having means for distributing this combustion air to the firebox hearth area.
An improved elongate firebox of the type having a central flue opening, a bottom, top, back and side walls, a frontal fuel receiving opening, and an elongate fuel support area of length "2 b" that exceeds the height "a" from said fuel support area to the top wall of said firebox as measured along the axis of said flue opening, the improvement comprising:
- (A) means, connected to the firebox for increasing the path length to the flue opening that products of combustion emanating from fuel located at ends of the fuel support area must travel from a value approaching .sqroot.a.sup.2 +b.sup.2 to a value approaching a+b;
- said means including a flue assembly having an annular entry opening spaced below said top wall for momentarily entrapping rising products of combustion above the level of the annular entry opening;
- (B) glass doors forming the fuel receiving opening in the firebox;
- (C) a preheat manifold extending along the bottom wall of said firebox between the front wall thereof and the fuel support area and including a plurality of combustion air inlet apertures extending to and between remote ends of the firebox and at least one opening at one end of the manifold extending through the corresponding firebox side wall for receipt of combustion air;
- (D) an elongate baffle positioned rearwardly with respect to the fuel receiving opening and extending downwardly below the length of the annular entry opening and rearwardly to overlie said preheat manifold;
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- (E) common means in said central flue opening for selectively controlling central draft and combustion air admission.
An improved elongate firebox of the type having a central flue opening, a bottom, top, back and side walls, a frontal fuel receiving opening, and an elongate fuel support area whose length "2 b" exceeds the height "a" from said fuel support area to the top wall of said firebox, the improvement comprising means, connected to the firebox for increasing the path length to the flue opening that products of combustion emanating from a discrete portion of said fuel support area horizontally spaced a distance "X", from the axis of said flue opening must travel, from a value approaching .sqroot.a.sup.2 +x.sup.2, to a value approaching;
- a+x, said means including a flue assembly having an annular entry opening spaced below said top wall, a disc shaped baffle having a diameter approximately equal to the diameter of the annular entry opening, the baffle spaced below the entry opening so as to allow the products of combustion to enter the entry opening throughout approximately 360 degrees, and means, connected to the flue assembly and the baffle, for adjustably positioning the baffle below the entry opening, where the distance "x" is equal to or less than "b".
A free-standing convective heating unit for use with a chimney, comprising:
- (A) a free-standing unit (84) having bottom, back, side, and top insulative walls for defining a frontally open space, the top wall having an aperture communicable with a chimney for the escape of combustion products and at least one delivery conduit (86 or 88) for providing secondary convective air flow to a room;
- (B) a fireplace enclosure (114) mounted within the frontally open space of the free-standing unit, having a bottom wall (106) spaced above the bottom wall of the free-standing unit so as to provide for secondary convective air flow therebetween, side walls (108), a back wall (110), and a top pan (112) having an aperture for passing products of combustion therethrough, the bottom wall, side walls, back wall and top pan defining a frontally open enclosure, and the back wall of the fireplace enclosure spaced away from the back wall of the free-standing unit so as to provide for a space between these walls for the secondary convective air flow, this space having access of air through portions of the fireplace enclosure and also communicating with the delivery conduit in the free-standing unit for removal of this secondary convective air flow to a room;
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- (C) a firebox (10) mountable within the fireplace enclosure, having a bottom wall (12), top wall (14), back wall (16) and side walls (18) and pivotal glass doors at its front for defining a fuel access opening to the interior of the firebox, the firebox having legs (104) depending from the bottom wall of the firebox for spacing the bottom wall of the firebox above the bottom wall of the fireplace enclosure so as to define therebetween a space for the in-flow of primary convective air (96), the back wall of the firebox spaced from the back wall of the fireplace enclosure so as to define a space therebetween for the passage of primary convective air flow, and the top wall of the firebox spaced beneath the top pan of the fireplace enclosure so as to define a space therebetween for the exiting of the primary convective air flow (100) into a room, the firebox having a flue assembly passing through the top wall of the firebox to communicate with the aperture in the top wall of the free-standing unit for the escape of combustion products from the firebox, the firebox further having means communicating with the primary convective air flow for bleeding combustion air from this primary convective air flow into the interior of the firebox for combustion purposes;
- whereby the secondary convective air flow is in surrounding relationship with the primary convective air flow for the dual purpose of maintaining the walls of the free-standing unit at a relatively low temperature so that the unit may be enclosed within a room, and for purpose of obtaining secondary heat recovery between the fireplace enclosure walls and the free-standing unit for delivering this secondary convective air flow into a room for heating purposes, and wherein the primary convective air flow is delivered to the room for heating purposes with the combustion air obtained from the primary convective air flow and with the secondary convective air also obtained from the primary convective air flow.
A method of effecting substantially complete combustion within an elongate firebox having bottom, top, back, and side walls, and having a central flue opening therein, an elongate fuel support area having a length "2b" that exceeds the height "a" from the fuel support area to the top wall of the firebox, comprising the steps of:
- (A) increasing the path length to the flue that products of combustion emanating from fuel located at ends of the fuel support area must travel from a value approaching .sqroot.a.sup.2 +b.sup.2 to a value approaching a+b;
- by establishing a flow path of said products of combustion first upwardly above the level of said flue opening, then laterally toward said flue opening and then downwardly to exit said flue opening;
- and
- (B) establishing a stoichiometric oxygen supply across the fuel support area.
Dependencies are inferred from the claim text.