US2676583A - Downdraft stove - Google Patents

Description

v April 27, 1954 E. J. BLUMSON DOWNDRAFT STOVE F:i .led March 8, 1949 5 Sheets-Sheet 1 V E. J. BLUMSON A April 27, 1954 DOWNDRAFT STOVE 5 Sheets-Sheet 2 Filed March 8, 1949 April 27, 1954 E. J. BLUMSON 76,

' DOWNDRAFT' STOVE Filed March a, 1949 5 Sheets-Shed a i E. J. BLUMSON April 27, 1954 DOWNDRAFT' STOVE 5 Sheets-Sheet 4 Filed March 8, 1949 5 Sheets-Sheet 5 Filed March 8, 1949 Patented Apr. 27, 1954 DQWNDRAFT S'IQXZ-E 'Ernest" James Blumsom, London,"Ei1gIand," as

signorto Allied lronfounders'liimitedi Ii'ondon; England; a-British' company-= Application; March 19% Seriab N o. 80,26:3.

Claimepriority; application Great Bi-itain -March 165 194.8

This invention relates to.- stovesaofi'theakindin which: a fuel' hopper xtendsz upwardly from-5a combustion" zoneto-which solid fuel contained. the hopper feeds by gravityaandiinwhichr'the whole of the primary. air for" combustion? passesdownwardly through. the? column offuel. maintained' in the hopperto the combustion zone, while secondary air is admixed.withtheproducts of combustion-passing: from the combustionv zone to effect complete combustion. of the smoke and/or: soot-formingproducts.

In constructions 1 of stoves" off this kind heretoforev proposed; the primary air" andrsecondary air" areadmitted to the; stove structure through separate iniets which: are separatelycontrollable;

The rate-- of combustion of the stove is deterrminedbycontrolof the inlet for primary air; and the inlet=:f .or secondary-"air is :separateiycontrol:- lablev to achievev the desirediconditions of. cornpletea combustion;

The present invention has for'its object-taprovide' an improved! construction of stoveofthe kind referred? to; wherein any fi1el,: butin particular: bituminous coal or other highly volatile solidi fue1,-may be burned: with. a: minimum: of

smoke or soot, and in general moreefficient:come bustion may be obtained without the necessity of relative adjustmentizof separate-airritriets:according: to the: desired rate: of? combustion;

According to the: present: invention, imaa stove of the kind referred to; aii -iszadmittedhthrough a singlecontrollables-airz inlet to a chamber below the grate-cor" other. fuel support;- in: which. chamber: it' is pre-heated and: from which; it: dis tributed": in proportions: determined? by: the relaz tive crossssection' of"distributing'rpassagesonfiowcontrolj; openings therein: to asupplyrthe: primary air; tow the; top of: thehopper and the. secondary air to the products of combustion passing from the"zoneeoicombustion;

In one embodiment the air is admitted: ton-and 'distributed"from= an: ashpit: chamber: disposed below an-imperforatezfuel support structure; The

imperforate fuel support" structure may be mounted-tobe capableofreciprocatiomunden the control of external actuating means counterrweighted flap members-being arranged soas to seal ash outlet passages between lateraledgesof the fuel support structure 'and the adjacent structureof'the'stove. I

In: anotherenrhodimerit; a; perforatevgiate structure is -utili/'zer11"in' conjunctiona sealed ashpit preventing access" of" air; thereto. and." the air. isadmittedito and-distributedf from. a: cham.-' ber extending around'the aslipit;

vent entry-of air,- counter-weighted flaps 2d, are

ment:

may be agitatedby-a to and fro movement.

or substantial thickness;

"Theinventionw isaliereinafter' described, by way ofwfexampleyv with: referenceito the accompanying diagrammaticdrawings; which- Fig.- 1-- isnazsectional side: elevation: illustrating a continuous combustion convection heaterv'constructedi in: accordance with the present invention;.

Fig is a; sectional 'front elevation correspondingtoFig. 1';-v

. Fig. 3iis-a sectiononthelineIIL-III of Fig; 2;

Fig; 4 is a. view: similarrt'o: Fig: .1- illustrating a modification; and

Fig: 5' is aisectional front elevation correspondingztot Fig: 42

Irv-carrying the invention into efi'ect according to: one-embodiment,- and -w-ith reference to' Figs.

1. to 3 of thetaccompanying" diagrammatic drawings; a..'continuous1burning convection heater comprises. axvertically disposedchamber I. of

rectangular: OIfOSSF SGCtlOH forming" a fuel hopper in-whiclrisiaestablished a column of fuel'that feeds progressively downwarwto a combustion zone l w locatediat-zthe lower end of 'the chamber l said chamben'beingprovided with a. door la at the front fora charging the' hopper; and a flat roof lb healer prod ecting: teetlr. 2e 01" the like which v slide overrsimilan-memhers i I projecting from; an ad'- jacentt, part? of. the stove; the structure thereby providhigugrids for ash riddling. In order that the" ash outieta may be. normally: sealed to prearranged to contact the lower'edge' of the fuel support i and of' the a'djacent'xpart of the stove structure when the-fuel support 2 isin the intermediatez'position' between the limits of its move- The' -sidewalls' lc' of the chamber i are constituted oyslabs of-suitabierefractory material At the outer side of these; refractory; side; walls [0, channels Id are provided, saidhhannels' i at being coveredfby plates 4 :50 as to form'tverticall fiues 5"=which' communicate atia vsuitable:hei'ghtlabove thegrate 2 with the" combustion zone through inlets 521. At the the hot zone Ida of the fire. secondary portion of the air from the ashpit 3 also passes up through the passages Na and II top the said flues 5 communicate with a passage 6 extending over the roof Ib and leading to a flue I communicating with a chimney outlet 8.

The rear wall Ie of the chamber I, which wall also may be of refractory material, has an outer wall 9 spaced therefrom to provide an upwardly extending primary air duct It at the back of the chamber I and extending the full width thereof. This duct Ill at the botom communicates with the ashpit 3 below the fuel support 2 and the rear wall Ie of the chamber I extends short of the top of the side walls Ic so that the duct I is in communication with the chamber I at its upper part. Passages I la for secondary air also extend upwardly from the ashpit 3 and. communicate with passages II disposed externally of inclined walls Ig defining the combustion zone and leading through openings I2 to the fines 5, the openings I 2 in this embodiment being suitably positioned above the inlets a from the combustion zone so that the secondary air from the passages I I is introduced at zones which normally are incandescent, thereby ensuring complete combustion of volatile or smoke and soot-forming products.

In accordance with this invention all of the primary air for combustion with the solid fuel and all of the secondary air for ensuring complete mounted on an ashpit door Sb. A primary portion of this air passes through the duct I 9 behind the chamber I to the top of the chamber and thence downwardly through the fuel it so as to carry volatile products of combustion to or into Furthermore, a

to the fines 5, the primary and secondary portions of the air being distributed on these two main paths in suitable proportion by suitable determination of the relative cross-section of the respective air passages or of flow control openings associated therewith at any suitable point.

In the modification illustrated in Figs. 4 and 5, the general construction of the stove is similar to that shown in Figs. 1 to 3 except that the plates ll of Fig. 2 are replaced by refractory slabs 4a.

til

grate bar structures 2e, 2 may be relatively movable by any suitable means for eifecting ash riddling.

In both embodiments, in order to obviate outrush .of flame or smoke when the door la is opened for charging the hopper, a valve plate I5 is supported by means of cams IEia mounted upon or operated by a locking handle I6 on the door Ia so that when the handle It is turned to unlock the door la, the valve member I5 is permitted to drop so as to open an outlet I9 and thus establish direct communication between the upper part of the chamber I and the through passage 6 across the top thereof before the door Ia is opened.

The stove structure is enclosed in an outer casing l1 providing air passages Ila for convection currents, said passages Ila having inlets ill? at the bottom and outlets Ilc at the top. The upper part Ild of the casing may have an opening Ile and the top We of the stove structure may be provided with fins lm for more effective radiation of heat therefrom. As shown more particularly in Fig. 3 the side walls in of the stove structure may be provided with fins I2 Instead, however, of providing an imperforate fuel support structure for preventing passage of air upwardly through the fuel supported thereon, a perforate grate structur is provided comprising grate bars 2c, 2) fixed on cross members 29,

21?. respectively, said cross members being supported on fixed members 21', and in order to prevent upward flow of air through the fuel on the grate, said grate is enclosed in a sealed ashpit 3 having side walls Ir, a rear wall Is, bottom wall lo and removable front panel It, the latter being held in place by suitable means, such as a spring Isa associated with the damper I3 on the door 31). This construction of ashpit provides an air passage I I0 at the front extending downwardly from the damper IS, an air passage I Ib extending beneath the ashpit, air passages Ha extending up the sides of the ashpit, and at the rear a direct from the passages H are disposed in the inclined walls Ig and communicate with zones in the vicinity of the inlets 5a to the fines 5. The two It will be understood that, owing to the arrangement of the air passages in or adjacent walls of the vertical chamber, the air supply is effectively pre-heated.

Furthermore, it will be understood that the invention is not limited to th particular embodiment hereinbefore described. For example, instead of the air passages iI extending upwardly from the ashpit 3 to the fines 5, they may extend downwardly from the upper part of the air duct It so that in effect the subdivision of the air supply takes place at the upper part of the chamber i. Moreover, the grate may be of conventional construction so that the air supply is distributed in three paths, i. e. upwardly through the grate in addition to the two main paths before referred to.

Furthermore, it will be understood that the invention is applicable to other constructions of stoves of the kind referred to, and the arrangement and disposition of the air passages may be modified in various ways.

I claim:

1. A magazine-feed solid fuel burning stove of the down draft type comprising an upright chamber constituting a hopper for receiving a column of the fuel, a support at the lower end of said chamber for the lower end of the fuel column to establish a combustion zone in the fuel column limited to the lower part thereof on the support, wall members forming an air distributing chamber beneath said fuel support, adjustable air inlet means to said distributing chamber through which the entire air for the stove passes, means pre venting air flow upwardly through said fuel support into the combustion zone, air passageways extending from said distributing chamber to the top of said upright chamber through which the whole of the primary air for combustion passes upwardly and thence downwardly through the column of fuel in said upright chamber to the combustion zone, exhaust passageways leading from said combustion zone to the exterior of said stove through which the products of combustion are conveyed, and passageways leading from said distributing chamber to the vicinity of the entrance ends to said exhaust passageways for introducing secondary air for burning off any unburned combustible products entering said exhaust passageways.

2. A magazine-feed stove as defined in claim 1 wherein said fuel support is imperforate, being provided with normally closed ash outlet passages between lateral edges of said fuel support and adjacent members of the stove, and said air distributing chamber comprises an ashpit disposed below said fuel support and ash outlet passages, said ashpit being normally walled-off from said combustion zone.

3. A magazine-feed stove as defined in claim 2 wherein said imperforate fuel support is provided with means whereby the same may be reciprocated and wherein counter weighted flap members are used to normally close oil said ash outlet passages.

4. A magazine-feed stove as defined in claim 1 wherein said fuel support is performated, an ash pit disposed beneath said perforated fuel support normally communicates with said combustion zone, said ash pit being sealed against entry of air, and said air distributing chamber extends around said ash pit.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 231,163 Hamlin Aug. 17, 1880 573,170 Watson Dec. 15, 1896 603,967 Piron May 10, 1898 725,228 Deprez et al. Apr. 14, 1903 2,399,814 Martin May 7, 1946 FOREIGN PATENTS Number Country Date 224,116 Germany Jan. 10, 1910 422,302 France Jan. 16, 1911 50,816 Norway May 9, 1932 808,783 France Nov. 24, 1936

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