US1999442A - Combustion apparatus - Google Patents

Description

Aprrl 36% H935. L. w. @GREEN m* AL COMBUSTION APPARATUS 2 Sheets-Sheet l Filed Feb. 18, 1932 INVENTORS ATTORNEY April 3(0), H935, l.. W. CORBETT AL,

COMBUSTION APPARATUS Filed Feb. 18, 1952 2 Sheets-Sheet 2 ATTORNEY Patented Apr. 30, 1935 PANN? ore-ICE' 1,999,442 coMis'Us'rIoN APPARATUS Lawrence W. Co'rl'lett', Belmont, and Ralph Ni Doble, HinghamrMass., assignors, bydirect and mesne assignments, of thirty-three per centto` Blanche L. Doble, Hingham, Massi., thirty-.four per cent to William H. Doble, Quincy, Mass.,v and thirty-three per cent 4tosad LaWren'ce`W.

Corbett ApplicationFebruar'y' 18, 1932; Serial"No;-593, 736

3 Claims.

This` invention relates to combustion apparatus for burning? solid fuel, and more particularly to heating apparatusr for domestic purposes, such as toapparatusfforheating dwelling houses and garages, moderate sizedbuildings, and also for heating water for domestic purposes.

Inf general, the invention has for an object to provide a novelI and improved construction of heatingV apparatus of the character specified which is adaptedrto efliciently burn various commercial grades of coal and coke in such manner as to avoid interruption in its operation by reason ofthe formation of clinker in the fuel bed.

.1. ll'itlrV this vgeneral object inview, and such 1 others as may hereinafter appear, `the invention consists in the combustion apparatus and in the structures, arrangements and combinations of partsfhereinafter described` and particularly de* fined in the claims at the end of this specification.

In thedrawings illustrating the preferred ernbodimentof the invention, Fig. l is a vertical sectionalv view of the preferred form of appa-- ratusmg. 2 is a vertical sectional detail through the upper portion of the conical grate showing a portionv` ofthe mechanismprovided for 'cooling the grate; Fig. 3 is a cross `sectional view taken on the line 3 3 of Fig. 2 viewed in the direction of the arrows; and Fig. 4 is a detail in side elevation of afportion ofthe apparatus shownin Fig. 1

t illustrating the grate moving mechanism.

In general,l the present invention'contemplates acombustion apparatus for burning solid fuel,

such asY any of the commercial grades of coal' orV coke', in which provision vis made for reducing to a minimum the interference with the operation of -the apparatus by'reason of the adhesion of clinker to-the grate.

In-the preferred form of.Y apparatusa rotatablev and preferably a conical grate is operatively sup por-tedwithin a combustion chamber; andprovision-is made for depositing fuel upon theupperf portionfof'the grate to maintain a substantially uniform fuel bed upon the `grate as `combustion proceeds. During combustion provisionisfmade formoving and preferably rotating the grate, to

effect Vdischarge of ashfrom the lower portion of the fuel bed and to elfect Vagradual and progressive movement of the burning fuel bed ldown the grateduring periods of active combustion `as dis-l tinguished from bank re periods. In order to prevent adherence to the grateof any cli'nker which may form within the fuel bed, and in order to reduce to a minimum the tendency to -form clinker, provisionis made ffor coolingvthe grate 55: and :particularly l theupper portion thereof dur-v -tion of thercombustion chamber.

(Cl.l 11W-36) preferably comprises wat'erf'which is generated" into steam by heat absorbed from the grate; and the steam thus forrnedisz preferably distributed through portions of the fuel bed.

Referring'now to the drawings, the invention isforpurposes of illustration shown Ias embodied in heating apparatus suitable for heating dwelli ing-houses and other moderate sized buildings, and'for general water heating purposes,` in which larepre'sents a combustion chamber, I2 aconical-grate, lli a supplyhopper for retaining, av supply `of the solid fuel such as coal' from' Whichthe-coal isV discharged through a coal/discharge tube i6 down onto V-theconical grate." The-end of the discharge tubeterminates a short "distance above'theconical grate, andduring the opera-e tion of the apparatus a'const'ant bed of fuelis` maintained inthe position indicated by the dotted-line 25 in'Fig; l. It ispreferred to construct theconical grate lof a plurality of" sections-26' which interlock to rotate as a unit, and 'the'lo'wer section 35i is preferably cast tofprovide` aski-rt 32; the upper surfaceof' which is` preferably sube stantially horizontal and of a 'sufficient Awidth so that theskirt projects outwardly a substantial distance beyond the inner wall of the lower por- Thelower por-Y tion of the inner Wallis-provided with ribsx35' for cooperation with the rotary grate in grinding ash and such clinker as -may beformedlv The' upper'surface of the skirt 32 is spacedfror'nthe lower portion Vof the inner wall of the 'combuseV tion chamber to form aI throat orconstricte'd passageindicated at Y38;'

The' conicalg'rate I 2' is, as herein shown, made' up. of aplurality of sectionsfand each' section isprovidedl withdepending lu'gs' 4l which vcooperate with recesses inthenext succeeding-sectionto lock the sections`A together and toi-space one sec-` tionva short-distancerfrom the next'lower section so `as to provide a series of downwardly and 'out-1- wardly extendingfair channelsi through which the primary air maybe causedto pass through the fuelrbed supported-upon-thegrate. The lower section of vthegrate is 'bolted'orotherwise securedto a ringtslhaving a ring gear 44 co# operating with `a driving pinion '45 secured'upbn the end of a vdrive shaft ll'rotated through suit-r ablemechanisrn, as willfbe described. The grate isisupported on a series of yball-bearingsl5!) with# in a raceway formed by cooperative surfaces 5l, 58 of portions of the lower section of the grate and ring 43 respectively, and the remaining sides of the raceway are formed by an angular recess in a supporting ring 59 mounted upon the frame, as shown. The skirt 32 projecting from the lower section of the grate is provided with a downwardly turned lip 50 extended over the supporting ring 50 illustrated in detail in Fig. 1 to thereby assist in protecting the bearings against the entrance of ash and dirt.

The conical grate 2 is hollow, and as herein shown, cooperates with the bottom wall 54 of the burner pot to form a closed chamber 58 to which air is admitted under pressure through an air inlet pipe 65 from any convenient source of supply, as for example a blower or fan, not shown. Duringthe operation of the apparatus the air under pressure from within the closed air chamber 55 passes through the narrow air passages 49 between successive sections of the grate to supply air for the combustion of the fuel. The construction of air pressure chamber 56 formed within the grate and burner pot serves to assist in preventing the entrance of ash or dirt into the bearings 50 by reason of the pressure through the bearings and outwardly under the projecting skirt.

During the operation of the apparatus, provision is made for rotating the grate, and as herein shown, the driving shaft 45 upon which the driving gear 45 is mounted, has aflixed to its outer end a ratchet wheel with which a pawl 'l2 cooperates to advance the ratchet wheel and consequently to effect rotation of the conical grate when the pawl is advanced. The pawl is carried upon the top of a pawl arm "|11, as best shown in Fig. 1, which is connected to an arm 16, the latter being connected by a link 'I8 to a crank 80. The crank 80 is arranged to be revolved from an electric motor 82 through the medium of a reduction gearing 80 of any usual or preferred form now upon the market. Provision is made for controlling the effective throw ofthe pawl i2 to control the extent of grate movement at each revolution of the crank 80, and as herein shown,a shield member 85 pivoted upon the shaft 45 is arranged to be moved relative to the pawl so as to slide under a pin projecting from the pawl to maintain the nose of the pawl disengaged from the teeth of the ratchet wheel for the desired portion of the normal stroke of the pawl to thereby prevent it from picking up any desired number of teeth. The pivoted shield is preferably connected to a control link 86 running from a thermostat or from a manual control.

In order to supply fuel to the conical grate to maintain a substantially uniform bed of fuel thereon, as herein shown, a bulk supply of fuel is stored within a fuel reservoir l5 located above the grate in a position from which the fuel may automatically flow onto the grate by gravity. The iiow of the fuel is controlled by the rate of consumption of the fuel bed in cooperation with the ash discharged therefrom and as long as fuel remains in the hopper a substantially uniform fuel bed is maintained upon the grate. During the combustion sufficient air is supplied through the fuel bed lto maintain practically the entire fuel bed incandescent, and the ash resulting from the combustion gradually slides and' works downwardly toward the restricted throat or passage between the skirt 32 and the dead ring 34 preparatory to being forced over the skirt to drop into the ash-pit Where it may conveniently be caught in an ash receptacle 92.

In order to reduce to a minimum the tendency of any clinker which may form in the fuel bed to adhere to the surface of the grate and thereby disturb the normal and efficient operation of the apparatus, and also for the purpose of reducing to a minimum clinker formation in the fuel bed when the apparatus is used upon low grade fuel, provision is made for cooling portions of the grate and preferably the upper portions of the grate by a medium other than the air passed through the grate to maintain combustion. As herein shown, the upper portion of the grate is formed so as to transfer heat therefrom to 'a body of water, effecting the generation of steam and the accompanying withdrawal of heat from the upper portion of the grate and the consequent cooling thereof. As shown in Figs. 1, 2 and 3, the two upper grate sections` |50, |52 are providedwith depending metal members |54, |56, respectively, and these depending members are made of sufficient length to project into and a substantial distance below the surface |51 of a body of Water received within the -standpipe |58. The standpipe |58 is preferably mounted upon the bottom wall 64 of the burner pot, and provision is made for maintaining a constant level of water within the standpipe |53 by any suitable constant levelv mechanism, herein shown as including a constant level oat valve |50 of known construction, in the water inlet line |52. A suitable drain cock |64 may be provided and also a shut-01T cock |56 in the line.

Provision is made for effecting the passage through the fuel bed of the steam which may be generated by heat transferred to the body of water from the depending portions |54, |56 of the grate sections |50, |52, and for this purpose the depending members |54, |56 are preferably shaped, as illustrated in section in Fig. 3, to provide vertical passages or channels |68 through which the steam may rise and pass outwardly between the grate sections. To facilitate the passage of the steam outwardly, both grate sections are fluted, as shown, providing a plurality of outwardly extended steam passages. In order to rotate the grate sections |50, |52 as the main body of the grate is rotated, the second section |52 is arranged to be rotated through a lug |10 which cooperates with a slot in the next lower grate section and the top section or apex |50 of the grate is rotated by the grate section |52 through the reception of a pin |14 in one of the steam channels |68, as illustrated in Figs. 2 and 3.

From the description thus far, it will be observed that during the operation of the apparatus, heat is withdrawn from Vthe upper grate sections |50, |52 through the generation of steam within the standpipe |58 and the steam thus generated is forced upwardly through the channels |68 and thence outwardly between the grate sections into the fuel bed. In this manner the uppermost grate sections |50, |52 are reduced in temperature sufficiently to prevent the adhesion thereto of any clinker which may form, and furthermore, the passageof the steam outwardly through the upper portion of the fuel bed has the effect of maintaining a certain porosity in the fuel bed and thereby reducing to a minimum the clinker formation as well as maintaining any clinker which happens to form in the shape of small pieces as distinguished from a solid mass. As a result, any clinker which does form works downwardly and is ground and discharged as ash. The diminution of temperature of the upper portion of the grate indirectly reduces to some extent the temperature of the fire immediately surrounding such portion of the grate and this of itself assistsv in maintaining clinker formation at a minimum.

While it is preferred to utilize water as a medium for cooling the grate, nevertheless other mediums in addition to the air passing through the grate may be used if found desirable.

While the preferred embodiment of the invention has been herein illustrated and described, it will be understood that the invention may be embodied in other forms within the scope of the following claims.

Having thus described the invention, what is claimed is:-

1. In a heating apparatus adapted to burn solid fuel with maximum heating efficiency, in combination, a combustion chamber, a conical grate rotatably mounted therein, means for slowly rotating the grate during active combustion periods to effect the travel of fuel and ash down the surface of the grate, means for automatically supplying fuel to the upper portion of the grate to maintain thereon a fuel bed of substantially constant volume and conical shape, air supply means adapted to maintain the fuel bed at incandescence during active combustion, said combustion chamber and grate being constructed to provide an open annular passage surrounding the lower portion of the grate for permitting free discharge of ash therethrough, and means for cooling the upper portion of the grate sufficiently to prevent adherence of clinker thereto whereby to enable unrestricted downward movement of the fuel bed when the grate is rotated, said means including an open container located within the conical grate containing a body of water, the upper portion of the conical grate being provided with a heat conducting depending portion extending downwardly into said container a substantial distance beneath the water level therein to effect a heat transfer from the upper portion of the grate to the water Within the container.

2. ln a heating apparatus adapted to burn solid fuel with maximum heating eciency, in combination, a combustion chamber,` a conical grate rotatably mounted therein, means for slowly rotating the grate during active combustion periods to effect the travel of fuel and ash down the surface of the grate, means for automatically supplying fuel to the upper portion of the grate to maintain thereon a fuel bed of substantially constant volume and conical shape, air supply means adapted to maintain the fuel bed at incandescence during active combustion, said combustion chamber and grate being constructed to provide an open annular passage surrounding the lower portion of the grate for permitting free discharge of ash therethrough, and means for cooling the upper portion of the grate sufficiently to prevent adherence of clinker thereto whereby to enable unrestricted downward movement of the fuel bed when the grate is rotated, said means including an open container located within the conical grate containing a body of water, the upper portion of the conical grate being provided with a plurality of heat conducting depending portions extending.

downwardly into the said container a substantial distance beneath the water level therein to effect a heat transfer from the upper portion of the grate to the water within the container.

3. In a heating apparatus adapted to burn solid fuel with maximum heating efliciency, in combination, a combustion chamber, a conical grate rotatably mounted therein, means for slowly rotating the grate during active combustion periods to effect the travel of fuel and ash down the surface of the grate, means for automatically supplying fuel to the upper portion of the grate to maintain thereon a fuel bed of substantially constant volume and conical shape, air supply means adapted to maintain the fuel bed at incandescence during active combustion, said combustion chamber and grate being constructed to provide an open annular passage surrounding the lower portion of the grate for permitting free discharge of ash therethrough, and means for cooling the upper portion of the grate sufciently to prevent adherence of clinker thereto whereby to enable unrestricted downward movement of the fuel bed when the grate is rotated, said means including a container for a body of water located within the grate, means for supplying water to said container including control mechanism for maintaining a definite depth of water therein, the upper portion of the grate being provided with a heat conducting depending portion extending downwardly into the container a substantial distance beneath the water level therein to effect a heat transfer from the upper portion of the grate to the water within the container.

LAWRENCE W. CORBETT. RALPH N. DOBLE.

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