US2864358A - Door mounted down draft flue for wood burning stoves - Google Patents

Description

Dec. 16, 1958 G. w. HARDING 2,864,358

DOOR MOUNTED DOWN DRAFT FLUE FOR woon BURNING STOVES Filed June 30, 1954 1N VENTOR fi. )Y/Ymd BY WM ATTORNEYE United States Patent DOOR MOUNTED DOWN DRAFT FLUE FOR WOOD BURNING STOVES George W. Harding, Lynchburg, Va., assignor to Automatic Draft and Stove Co., Inc., Lynchburg, Va.

Application June 30, 1954, Serial No. 440,428

4 Claims. (Cl. 126--77) This invention relates to down draft wood burning heating stoves. In such stoves, as in all other stoves for that matter, it is logical and conventional to have the smoke pipe connection at the rear, since the back of the stove is adjacent the chimney. This necessitates that the down draft pipe be at the front, which is also conventional, since for efliciency the air intake should be as remote as possible from the smoke pipe.

Obviously, since the front of the stove is occupied by the down draft pipe, the only place for the fuel door is at the top of the stove, and insofar as is known to applicant, all down draft wood burning stoves heretofore have had the fuel door on top. This high location of the fuel door requires that the chunks of wood which are generally heavy, be lifted the full height of the stove, and users have often wished that it were practicable to put in the fuel at a lower level.

The present invention has for its object to provide a down draft wood burning stove having a door at the front, closing an opening in thebody wall of the stove, the down draft flue being on the inside of the stove at the front, and having at least that portion which would normally obstruct the door opening, incorporated in the door so as to move with the door out of obstructive relation to the door opening when the door is opened.

- Other objects of the invention will appear as the followingdescription of a practical embodiment thereof proceeds. I 1

In-the drawing which accompanies. and forms a part of the following specification, and throughout the figures of which the same reference characters have been used to denote identical partsr Y I Figure 1 is a perspective view of a stove of the type described, embodying the principles of the invention;

Figure 2 is a section taken along the line 2-2 of Figure 1;

Figure 3 is a view similar to Figure 1, showing a modified embodiment of the invention;

Figure 4 is a section taken along the line 4-4 of Figure 3;

Figure 5 is a section taken along the line s-5 of Figures 2 and 3.

Referring now in general to the drawing, it may be stated that while the invention comprehends broadly any down draft stove that has both the fuel door and the down draft flue at the front, the specific stove selected by Way of illustration is one in which the down draft is regulated by a damper controlled by a thermostat mounted in heat exchanging relation to the stove structure at the upper end of the down draft flue, responsive predominantly to stove temperature, but having a modicum of control derived from room temperature effective when the fire becomes low to keep the damper open to a greater extent than it would be in response to stove temperature, to prevent the combustion from diminishing to the point at which the fire dies out. The specific thermostatic damper used as shown is fully described and covered in my co-pending application. Serial No. 403,497, filed January 12, 1954, now Patent No. 2,797,874, and is not per se herein claimed.

Adverting now in detail to Figures 1, 2 and 5, the stove as shown comprises a curved body 1 with top 2,

and bottom. 3. The lower part of the space within the stove may be considered the combustion chamber to which chunks of wood are supplied through an opening 4 in the front of the body, located at an intermediate point in the height thereof, having its lower edge above the bottom of the combustion chamber and being closed by a curved door 5 conforming to the curvature of the body and hinged at one side so as to open outwardly.

Within the body at the front is a flat plate 6 extending downward from a point above the door substantially to the level of the bottom of the door opening, said plate being flanged at the sides and being of such width as to assume chordal relationship to the curvature of the door when applied to the door. This plate is transversely divided at the level of the upper edge of the door opening into two sections, the upper section 7 being secured to the body of the stove and the lower section 8, to the door, by fastening means such as stove bolts engaging the side flanges. The two sections of the plate 6 are in registry when the door is closed, constituting with the door and with the part of the body that they subtend, a down draft flue 9. The lower part of the down draft flue swings outward with the door, leaving unobstructed space back of the door for the insertion of the chunks of wood into the combustion chamber.

The upper part of the down draft flue 9 communicates with an opening 10 in the body of the stove located above the door opening. The upper section 7 of the plate 6 has a forwardly extending upper end forming a top closure within the stove and the down draft flue, its forward edge fitting closely the curvature of the stove body abovesthe-upper edge of the opening 10.

Said opening forms a passage from the down draft controls the intake of air to the combustion chamber by" way of the down draft flue. The damper is controlled by a thermostat 15 within the casing 12, which is in thermal contact with the damper shaft and in heat exchanging proximity to the stove structure so that it responds predominantly to stove and not room temperature. However, in order to subject the damper operation to a minor factor of control responsive to room temperature, the thermostat is located in a vertical duct 16 open to atmosphere at both ends, through which a convection current of relatively cool room air contacts the thermostat during operation of the stove. While combustion is active, the heat from the stove to which the thermostat responds far outweighs the room temperature control factor, but when combustion diminishes, relatively cool room air accelerates the opening of the damper so that combustion is stimulated before the fire gets too low to be revived,

Figures 3 and 4 disclose a modification of the invention in which the entire down draft flue and including the there mostatic damper control unit are carried by the door, In this form of the invention the door is provided with an opening 18 therethrough in its upper part and carries on its inner side the flat laterally flanged plate 19 in chordal relation to the curvature of the door, and which is similar to the section f the plate 6 present in the Patented Dec. 16, 1958" first described modification of the invention. On the outside, ofthe. door is the casing12 defining the duct 13, which communicates through the opening 18 with the down draft fiue defined between the plate 19 and the portion ofl'the: door which it subtends; 12 isrsimila-r or identical with the-one illustrated in Figure 2, it is constructed to provide the duct lm in which the; thermostat l5 isr located, being fixedat one-end to the shaft 16: of the damper 14 The plate 19- is-angularly deflected toward the: door at the top -simila-rito theplate sectionlin Figure 2, with itswedget conforming to the curvature of the door andgfittingclosely thereagainst in a substantially: airtight manner. formsrohthe invention, is. thatathesentire thermostatic dampercontrolled down draft feature iswholly. carried by the. door;,-forrns part of the door structure, and can be manufactured and; sold with the door asa part thereof, and, installed; on wood stove bodies. having a suitable opening: at, the. front.

While I have in the above description disclosed practical embodiments of the broad inventive principle, it will be, understood by those, skilled in. the art that the main coneeptof, the invention is a wood burning stove having a down draftat the front with at least a part of the down draft, fiuecarried by the door and movable, therewith so that it is out of obstructive position, when the door is opened, with. respect to the introduction of fuel into the stove. It will also be understood that the broad concept of, the, invention includes anystructural means of forming the down draft flue, which is whollyor partially carried by the door at the front of the stove,

1. Wood burning stove'comprising a hollow body having its front wall of cylindrical curvature about an upright axis,, and havingafuel access opening in the front wall at an intermediate point between, the top and bottom of, said body, a laterally hinged door for closing said opening, forming part of the front wall of said body, a planiform partition plate within said body extending vertieally upward, from a level adjacent the bottom thereof, intersecting the inward geometrical projection of said fuelaccess opening, said plate being in chordal relation to the frontwallof said body defining with said front wall the inner limb of a down draft flue, said inner limb being ofsubstantially uniformcross-sectional shape and area throughout the .lengthof said plate, a fitting on the outer side of said cylindical front wall partitioned to form a conduit adjacent said front wall constituting the outer limb, of said down draft flue, open to atmosphere at the top and communicating with said inner limb through an Since the-lcasing The advantage of this i opened;

2. Wood burning stove as claimed in claim 1, said fitting being mounted on said front wall above said fuel access opening.

3. Wood burning stove comprising a hollow cylindrical body forming an enclosure defining a grateless combustion chamber having an unobstructed fuel access opening at the front at an intermediate position in the height of said enclosure, the latter including a laterally hinged door for closing said opening, a partition within said enclosure at the front, forminga down draft flue in conjunction with said enclosure, so much of said partition as is in conjunction with said door being swingable unitarily therewith,

said down draft fiuehaving its lower end terminating at a level adjacent the bottom ofsaid door opening andextending upward therefrom, and having anair inlet opening through said enclosure at its upper end, a casing on the outer side of said enclosure overlying said inlet open ing constituting the outer limb-of said down draft flue, a damper withinsaid casing controlling the inlet of air to said down draft flue, a thermostat within said casing having itsthermal element connected metallically tosaid enclosure to respond predominantly to stove temperature, said casing being open at top and bottom respectively over and under said thermostat, providing for an upward con vection flow of air at room temperature about said-thermostat.

4'. Wood burning stove as claimed in claim 3, said air inlet opening beingrin said door, and said casing damper and thermostatbeing carried by said door.

References Cited in the file of thispatent UNITED. STATES PATENTS 610,260 Culter Sept. 6, 1898' 666,460 Blanchard Jan. 22, 1901 938,543 Anthony Nov. 2, 1909 2,170,728 Montague Aug. 22, 1939 2,199,875 Brogden May 7, 1940 FOREIGN PATENTS 2,733 Great Britain Sept. 13, 1872

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