US2325655A - Apparatus for burning fuel - Google Patents

Description

Aug. 3, 1943. R. E. BRESSLER APPARATUS FOR BURNING FUEL Filed June 21, 1941 I'm/e berf Z firessjer u nin c e mummy Also, it is an objector the inyention apparatus 1 I "Referring nowin detailftothat embodimentpf;

1:1 ounge;

I outinthefapbended oleims The apparatus; with which the, present inven is (C Hoe-101 successively, oceurringl burnihgfiveyjcl'esi In one 1 said cycie, the} fuel isibiirnei faster man it is;

t One ofjthelobjectsfot the; present invention is to royide im ro eo mea s ttor eontrollirj gthe cyclingpctionot the apparatus andwhichnieahs is Simple in eonstr ietion Ior 1ow cost prodnetion v and at the same time: is automatic} ac urate and dependable so at i to he trouble tree in 'operdtion overlong periodsfofusfli reaaw: the fuel bed and wiie 'tn. fuel bed has burned downto a preueter men depth nothr Seriail N6. 399,111

biowe tothwumer to support oombiistion the biowe'rgg 1:

j. Another obje t. oi the invention is to provide improved eans for loontrolling thebyoling ae-u tion of the apparatus, which innotion slby reason o! the ohangefinpressure ot th'e supplied. air,

1 thus eiiminatingjthe necessity for the used! in; t

dependent cyole timing elements,jwhichiiierease means for this purpose, whereby the oyeling action: is ohtained ,without, momentarily; stopping the entire apparatus, thus relieving "the driving:

' motor of the epparatus i'r'oin ,imd iej starting torquesjandimaterially reducing the eonsumpption 0! powerrequireo for theaDDaratusQand The above mentioned objeetsoi the invention,

nithed 'aw n i Fig fl is a iew injside el evati'o nota fuel burn ing apparatus andl assoeiated l ecltrie circuit em;

bodying the invention," with parts of l the appee ratueshownin section or fasbrok'en away, better tov illustrate the parts involved. I

'Fig; 2 is a fverticaljsectional' .view, on an (e nf 'sive elements or diaphragn s embodied in" the the invehtion illustrated ingthel drawin and heiicalfiight Ntheteon of a1 dialmeter epm oxi-i v V mating the'insidegiiar eterv of eaidtubgjSectiong;

thereiorefasshring moreTeconoinical operatiomj 1 i hopperfi andthrough, the t rounded bottom or. the retort endmhere 1tter- 40 m n n the adrn ae e; o gi g retortjare tuyeres I Q whereby gir under pressure e 3 all in ludes a feed ,tjube section s thaflextendsfhrE-l V tweejrijthefrea'r end'oY; thelower portion of" the hopper 6 and 'the fuel inlet opening I5] I ,The

15181 feedingmea n's ras herein. showri also in'cludesb a secondtuble section l1 inaxigl alignment' with] thef rt mentioned one and which isdisposed.

*betweenhthe front end of th'e'lower portion of the hopbrangitherear side of an upright casing [8f located in' front of the hopper.

In the tube sections s and 'l1,,which are dis i 1 posedin the'rhegliahiiiigfbf the hopper, is'looeted a feed 's crew-gthat includes afshaft IQ WitI'iajf be sectionifijinto. the

' ing bearihg inthe fuel' in this part of theretortr 'I'hatend oi'jthefeed screwshaft disposed within thefllcasing IB- is operativekjonnected by speed larged scale through one dune brefss ire responegpjecislly to 1 thereoi, the iniproved appariat u s which is in the John pr; an ,ungierfeed stoker; includes a bur ers; a. the! hopper 6 and rediioi'ng gear ton. horizontal shaft; 22] thatis joujrnalled in the up perl e n d v or the casing "and extends trari$versely oiwthemsha ft of the feed' screw; one .nd; of 5 said. shaft 22 extends beyond one side ofgsaid easing where itisprovicieq with npfilleyj 23; T'hisrpulle y l sj driven by abelt 24 fim"? m lwli-on n e d m t r -1 1' t shzaifttof'thelmotoj11); The other emiof S id; r tu e; shangext n swin ojthe ca i g rime,

m we "8 51mm Qthei hfls'fl .f an or m of any tsuitab1ekindi(not-shownifseoured thereto i The duct {is operatively connected at one end damper for delivery to the fuel bed. i

to the disch arge or outlet side of the blower casing 8 and the other end of said duct is connected to the inlet of the Windbox I. In the duct 9 near the blower casin I'provide a damper 26 -mount'ed on a cross shaft 2'! that is journalled in opposite sides of this part of the duct. One end of this shaft extends outside of the duct where it has fixedthereto an arm 28. By means of the arm 28,;triedamper1may be rocked" from a ver -Q tical position, whereby' onl aininimum'voiume f air can pass the same, to a horizontal position whereby a maximum volume of {air can pass the To move the damper from one position to the other, ,I provide an electromagnetic: devicela having an armature 29a which ls -o'onnected a link 28a to the arm 28 on the; damper shaft.

When the device29 is deenorgized; the damper assumes a vertical and substantially clos ed-posi-' tion in the duct, and at this time only a minimum and opens at its otherend into the duct 9 at a point between the damper 26 and the burner 5.

, tacts Wand 41 respectively that are carried on V tween its ends.

The high pressure diaphragm device 30 operates a single contact switch 36 and the low pressure diaphragm device 3| operates adouble contact switch 31. The'switch includes a fixed contact 36a and a contact 361) carried on one end of an arm 40 which is pivoted at its other end as at Hi The diaphragm S4 of thedevijce 39 carries an axial stem' l l which extends upwardly to en;

gage the under side of the arm 4i! at a point hesepaiatedfrom itsassociated contact 36a.

Y Theiswitchfl includes space'd'ap'art fixed contoots- M and fi -respectively an associatedconone. end oii a. movable contact arm 48 which is volume of air can passthe samewhen'the blower is being, driven;byflti'ie motora WI'ieiiQthe device zs'isenergized;the damper is movedint its hoti z ohtal' andwide open position in the duct, per

mittiiigf thevpas'sage" of..' the maximlim Volume of airihroueh-theduot; If 3 I t From the alioyelit' .is ap'parent' that when the motor loiis energized; the blower is driven to 7 provide air under-pressure and the. shaft" I ot the when t damper, 'lt isi'n'; its substantiall closed pos'ition'ai dthemoto lt' 'is energized the fuel is fdrt'o' the retort faster than it can burn so that the, fuei bed ouilds u in depth and irovides, a

resist'eneehio the nassage of air' th'er'ethroug'h; which increases the ressure-of said airvin' the duct; When thedamper Z6 is iii itssubstantlaliy wide open oositionandthe motor "Li's energized; the fiiel'bed' burns atjarate fasterithanthe rate offeedofiiiei"thereto'so thatthe fuel bedburiis downindepth nddecr eases the, ressure or'the airinthe duct, The movemenvofthe' damper fromxits ciosedto its openpositionconstitutes one cycle of: burnihgeperation in a turnin period of" the a paratus, after which the" damper-is caused to freturn to' its oiosed position to initiate a; succeeding cycle andthe operationgoes on as before: j J

To move thefdaniper from one position to the other inorder to produce the cycling action, I

providethe'followlhgjmeans.

on an suitable part of'itfie apparatus'rprovide apairofipressi re sensitive device's 3U'a'n'd.3Ire-' spectively. As best shown in Fig; 2; each device so -'31 includesapair of" opposed casing parts Ii -3s respectively, with the" peripheralmarginai I part ofa-nexibie diaphragm 34* clamped bet'ween them; For convenience-infuture reference, I

I teimthedevicetlf the hlgh'pressure diaphragm device" and" the de'vice fiil the "low pressure" dia phragm device; The casing'partsioreach device 30%3'1 in connection'with the'diaph ragm slpro rides a pressure eiiamo'er-zt i'n'eacll device-at-the bottom" thereof. These devices wan-d arm -be Y located at' any'conyenientplaceon the appara'tus and preferably towardthefitontj'thereof: There:

tore, I have" shown both/of said devices as mounted on" a plate [to 'tfiatis' arranged alcove the motor" m"-a issupportedty abracket itaz- Ktiihe' ttf opens at'one'end into the chamber 35, ofithe thigh:pres ure." diaphragm (lei/168130 and opens ati its, etherpe dfmto the" duct, 9 ate point bet eon, the, casin is and the damperfztl filibther flibjsfif hs' atoneend'into the chamber 35 of the fflow pressured diaphragm device piyot'ally'mountedat its other end as at 49. The diaphragm 34 of the device 3! carries an axial stem 50 'which .extends upwardly to 'engage the' arm 48 atja'pointldetweenits endsf'A' spring 5| is so conn'ecte'd'to the aIInMl' as tonormally, hold i81'andassociated armature 59'. I 7 V 'I'Iiethermostat is usually: located in the room or space being heated; andi thejliinit control, which" is associated with the fuifnace; with which the apparatus. described is used, normally functionsas aclosed switch." The transformer ineludes" primary and 81' respectively; I W

62 and 63" indicate the main current: onductors leading from a suitable source of supplyr The conductortz' passes through the limit control 56'to acontact fiitassociated with the arma tare 59. and" a line: 65' connects said armature to one side" of'th'e' motorifiand to one side ofthe electromagnet 2'9: The other side of the motor is" connected byfa Iihe Gsto the fixed contacts 36a and oftlie switches 36 ands! respective 1y: The other side of'the 'elec-tromagnet 29 is connected" bya line 61 to th'e'iixed contact. 44 of the switch 31 while the main current conductor lit'leads tothe arm lugot the' witch 3B. The oppositeends ofthe primary winding of thetr'anse i formerfil are connectedby lines, 68, and 69 to the" main current" conductors 62" and Q3 respec' 1 ti'velyand' thei'opposite ends of' 'the secondary winding of said transformer are connected ,by

linesflli' and llto one sideofthe thermostat and toon'eside ofthe'coil of'the relay 58 respectively. The other side of the'thermostat and said armature are connected together by a line lz.

' Ina standbyor non burning period of the ap-,

aratus, when the-thermostat 55 is notjcalling for heat, the armature 5915i out of engagement with" the contact so that the circuit is open; When the circuit is open, themotor It! is deenergized'so" thatfth'e' shaft ia'ei the feed screw and'the' bloWerB are stopped. At this time'atmo'sph'eric'pressure exists intheduct l1, and the damper 26 thereinJis inthe closed position. At this time atmospheric pressuregis present in the chambers, 35"of the diaphragm casings of the pressure resp onsive devi'ces 33,-an'd 3| so that the contacts Bite-36!) are disengaged, the contacts A spring 43 is so connectedfto the ann 40 as to normally'hold its contact 3612 secondary windings and deptln' t When the fuel bed has burned down to a predetermined depth, its resistance to the passage of air therethrough is reduced, so that the pressure, of the air inithe, entireqduc't 9- is likewis e reduced. When a predeterniined lower pressure isreached in the duct under the conditions above noted, .the contact 3617 is disengageddrom; the contactitdso that the circfiit to the motor l l, 2,325,055, u and 4a "a e disengaged {while the conta ts a u p and are engaged, t l it When the thermostat ll calls tor -heat, the coilof the relay "becomes energizedf'anddt attracts its armature 59 toengage the same with the con =tact 64. This closes a circuit 1mm thefiline' 62 contact 64, armature as, through the '1inefii5'to one side the motor 10, outthe-other sideof the motori bymeans of line to contacts 38a and 45. As the contact 41 is engaged'with thecon-T tact ltlcurreht passes through the switch ar n l8; connector ilto switch arm lllto line 6 3. The i metor is'nowienergized[anddrivesthe shaft l9 l go -the feed screw, to feed fuel to the bed on the i The motor alsddrives theblower Ito provide air underpress'ure to support combustion'l' -At this tini'efthe damper is closed so f that only a minimum amountof'air can pass the same to provide a relatively low-burningirate ior H the i'uelbed anti which rate islower than the ,fe'edihgcraterof fuel tofthje} fuel bedlu a closed, the U pressure of the air in the duettbetween thedanip f erand blower builds "up and-isexerted through i the tubesa wca e the-diaphragm3lot=device As the darnper at'this ftlmefis'still 30, at some predetermined pressure, in the-easing oi. the pressureiesponsive device 30, to function through" itsstem 42 to operate through the arm dB-to engage; the contact 3 36 5 with the contact 1, 880. This closes asecond part0! the circuit for 3612-486 and arm lll to, the line 63. 1

* -Thelswitches 36 and :1 are so setthat at a pie; determined pressure in the windboi'r and' in the duct 9 between the ,windbox and damper, said pressure functions through the diaphragm 34; in

the-cas ng of the pressure responsive devicejl contact in engagement withsconta'ct 2 n v this arm llj swings downwardly and disengages the contacts 46-: and reengages thecontact- H with i the contact- 45; This :flnishes one burning oy'cle since when 'the contacts 465- are diseri gaged, the circuit to the electromagnet'flbpens and thesame is deener'gize'd: perinittingthe damperagain to"close. a i Asthecontacts fi fl areatthis timeen V F gagedfthecircuit is -'again eompleted to the-motor,lbei.'ore;iti comes tors-dead 'stop,,soi asto rea enerkize =and- 'restart'it agalnto initiate. another burning cycleas before.- Thus, the fe ed oi' fuel end, of, each burning-cycle, it' is again closed so 1 shortly thereafter as to berestarted againbefore to cause its stem 50 to swing the arni 48 upwardly ,to' disengageits contact 41 from the contact andfeng age its contact ll*wlth the cohtactj.

, 'I 'hisjcloses ahcircuit through] the lin'e65 to one side of the electromagnetland out" theother side, and through line 61, contacts "-46, armila; connector 52 to arrnjliand thenout through the maincurrent conductor. i I

' This energizes the-electromagnet 29 which into operation at gages i'rom the' contactitlgwhereby the circuit to thewmotor is broken and the. motdr' 'stopsr Whemthe motor stops,-the partsreturn "to the positionsshown in Figfil, ready to initiates'am it stops entirelyi theslowing down of the motorandi the attached blower causes a 'reduc-\ tion in; pressure in the, duct to produce the recycling action by initiating a succeeding burning "cyclebefore thernot'or stops. 1 Hence, the motor being still under momentum, sta'rtsimuch easier the beginning of each cycle of operationw I p Whenthe thermostat l5is fsatisfied-in its demand for{hea t, 'it opens-{the ,circuit to the relay I58 soj that-the armature drops away or disenother burning'cycleas soon" as a burning period lsf'necessary to satisiythedemand' for heat'by thelthermostat. i i w 1 While in describing the invention Iw-have re-- erred in detail to the-form, arrangement and constructionj'ot thepartsiinvolved, the same is to i be considered only in 'thelllustrati've sense and therefore I do not'wish to' be'limited theretoex-' cept as may be specificallyi set Iorth'in the apswings the damperliintofitsopen horizontal it plurality ot fixedrates, one faster than thefeedpositionfor the passage ottheimaximum amount of air -pastthe same. 'I'he' IueIbed; having'bee'n 1 w previously built upto aoonsiderable depthgthen starts to burn at a rate that is faster than the feeding rate offuel thereto and thereiorethe fuel bedburnsdownindepth. i I when the damperis opened, after a'iuelfbed. build ;up, ithepressureot the air in the entire Iclaimagmyinventionz a 1., Apparatus forfisubstantially power burning solid fuel in cycles each'having a and ern'bodying therein'a retort for supporting'a duct is the samebut it is; still suflicient to iunction through the diaphragm in'thecasingof the a 3 device 30 to hold the contacts 360 and him the engaged position pending a reduction in iuel bed is openedand the motor reducesorslows down ducesl in pro zuqrtioi'r and this momentarily causes a pressure belo w'that at I which the diaphragm in the casing of. the device 3| i ls able t'o maintain fuel bedpmeansfor feeding fuel to the retort,

an air duet leading to the retort, means for inov in; air through the air duct, means forhriving said 'fuel" feeding means and said air moving v means, a damper associated with the air duct and having' relatively heavyyandrelatively light air;

resistance positions, said driving, means being adapted to drive said-fuelfeeding means to feed fuel to the retort at a rate faster than the burriing rateof the ;fuel bed when; the'damper isin its relatively heavy. air resistance position, means operative upon apredeterminedincrease in air 7 pressure in said duct to moveflthe damperto' a] relatively light air resistance'position whereby .1 i the fuel bed is burned at a rate fast-er than the,

feeding rate, and rneans operative when the pressurefof the fairin the air duct reaches "a 'predef termined lower pressure conditionto deener'gize saidldriving means so thatfitslows down and so drivesj'the air moving means, asto produce a'still ,lower pressurein saidduct to return the damper to said, relatively heavyair resistance position andthereby"reenergize said driving means to V 1 initiate another burning cycle.) f

c continuously :i 2; 1Apparatusr, for substantial-lye continuously power burning: solid'fuel: in cycles, each having a-plurality?of:fixed rates, one faster than the feeding rate and another slowen thani the feeds ingyrate during-"a burning; period of theap-r.

' 'paratus-and-embodying thereiira retortforsupportingw a fuel zbed,,means'; for feeding fuel to the retort, an air duct leading to theretort m'eans formovingjair throughthelairduct, a motorfor driving said fuel feedinggmeans andsaid air moving meansa damperassociated: with the airduct and-'havi-ng relatively heavy andrrelativelyzlight air resistance positions;welectrically p'operable means for moying; said damper from, one of-said positions the other thereof; a; circuit-for said [motor and said. electricallyioperablemeans; said motor being adapted to drive said-fuel feeding means to feed'fuelto'the.retort at a-ratesfaster than; the burningrate of the-fuel bed when-said damper is in: itsrelatively heavyfair" resistance position; switch means in said circuit forcontrolling the" same,ja partof said switch vmeans normally holdingithe circuit closed atone point ,tothe motorand open tosa'idelectrically'operable-means, pressure responsive meansfor actue eating saidfswitchmeans; said pressure'responsive means operating through another partjoi said switch; meansupona predeterminedincrease'of v the duct andthroughsaid switch meansfirst to open said circuit at said second pointto said motor and later to said electrically operable means and close saidcircuit to :the: motor at said first point so that said-damper returns -'to its rela tively heavy air resistance positionand 'said'mo tor is reenergized before it stops to initiate-another burning cycle for the apparatus.

3. Apparatus for substantially continuously power; burning solid fuel in cycles: eachhaving a pluralityof fixed rates; one faster than the feed-' ing rate and another slower than the feeding rate during a burning period of the apparatus and embodying therein a retort for supporting a-f uel bed, means for-feeding fuel-to the retort, an air duct leading to the retort, meansfor'movingair through the air duct, a motor for driving: said fuel feeding means and said airmoving means, a damper associated with the air duct and having relatively heavy'andrelatively light air resistance 'positions,,electrically operable means for moving said-damper from one of said positions toithe other thereof; a-circuitfor said-motor and saidelectrically operable means, said motor being adaptedto drive said fuel'feeding means to feed fuel to the retort ata rate faster than the burning rate of the fuel bedwhen said damper is-in itsrelatively heavy air resistanceposition,

a switch insaidcircuit for controlling only the operation of said motor, a second switch in said circuit for controlling jointly the operation of said motor andsaid electrically operable means, pressure responsive means-for actuating the first mentioned switchand operatively connected to:

said duct at one side, of the damper, a second pressure responsive means forpactuating said second mentioned switchand operatively con-- to maintain the same energized, said, second men- 2,32 new I I V V n'ected to the duct nQtheother side of th'edam-per and normally acting througlritsswitch'to hold saidcircuit closed-to the motor "and; opened to said electrieally operable means at a lower pres sure ofair in said jd iet so thattheidamper nor-,

mally remains in said relatively heavy air re sistance position, said first .mentioned pressure responsive means operating through its switch,

upon'a predeterminedzincrease-of air pressure in said duct to close said circuit to said motor tionedv pressure responsive means operating through its switch at saidincrease in pressureto open thecircuit to the motor andgtov close the;

sametc saidlelectrical ly operable means so that it causes said damper to move,tosaidrelatively light'air resistance position whereby said fuel switch to open the circuit to saidelectricallyoperable mean sothat the damper returns to its substantially heavy air; resistance position and toreclose; said circuit-i0 said motor before it stops and" thereby tol'initiate anotherqburning cyclefor-the a aratus,v 4. In. a fuellburning apparatus having burning periods; each. constituting a plurality of successively occurring burning cycles,';the-comoination ofa reto1jt, means for feeding fuel to the retort to form afuel-bed-thereon; meansfor supplying air under pressureto the; fuel bed to support combustiontliereof,ineansfor driving said fuel feeding, means and said air supplying means, means operative in a burning period'of the apparatus for controllingthe volume of air supplied to the fuel-bed, means-for initiating a burning cycle for theapparatus and embodying-therein means for connectingsaid driving means at one point; to said-fuel feeding: means and said air supplying means for driving the same and: for causing said controlling means toreduoe the pressure and the volume of the air supplied to the fuel bed a so that fuel isfed-tothe retort-faster than the supplying means at another point and for disconnecting'said driving means from said fuel feeding means= and from said air supplying meansat-the first-mentioned pointand for causing said air controlling means to provide a max- 5. In a fuel burning:apparatushaving burning periods, eachconstituting a plurality of successively occurring burning cycles, the combination of a retort, m'eanslfor feeding fuel to the retort to'forrn a fuel bed thereon','a1neans forsupplying.

air under pressure to the fuel bed to support combustion thereoiamotor for driving said fuel feeding means, and 'said air; supplying meansg'a heenre su ei nd the v lu e a e airvsupplied H to, thefuel -,be,d so that fuel iisied to the-retort. faster than the burning rate thereof and whereby, Q the fuel ,bed, builds up linedjepthe and increases its sisian t t e pa e i e1 h m h i 1 in e e th Pre ure er of and me s ov r- 3e a e :tn t c o ioft he n ea e re s r 2 thesu ii s ne e iaa eid i cui r S i m t: ano he Pa t and u f r i Sa cir ui 1?, he t e i' edi m n or ca s n said air controllingmeans to provide amaxi mum ,vo lume of air under pressure tothe fuel bed so' itslburning rateis faster than its feeding i a e e a her y sa f el b u s down in :dent ami ec ase s r s s n to 'eir upnned-1 v 1% thatw ch i i iate a su e d n n e c e at Pr u e w e sldeq eas for; the apparatus duringlahurningperiod.

, i r recu r n h r ias le -the com ieei ai lei-fi a m means rme nzg n lqther to? ,to,form a fuel bed thereomineansf for supb yr 1 1e r. u i rPr SuIewith uelbedb up rt i combustion thereof, 1 means for; I driving: said fuel l a n ns a a r ip l in a e t electrically operated means for controlling f the Me a Q f u p edsto t e l a P 9 for said electricallyr operated means, means operf ative in alhurning' period of theapparatus for i g initiating a burning eyes for the apparatus and embodying therein means for connecting] said flaming {means at .onefpoint tdsal'id lfuel feeding and said air. supplying means for driving the same" andforso changing the condition of circuit as to cause said, controlling, means to reduce the pressure.andftheyolume 0f the .t air suppliedto thefuel bedso that-fuelfis'fedx the'retort faster tl'i'an the burning rate there [of and whereby the fuelfbedhuilds up depth andlincr'eases "its resistance to thepassage of air therethrough toincrease the pressure there? =ir it f r said ma h meen ia eo wl ns th r v'alum f 1 a r i u dim s id fu be n a 1 er tive in a ch rn n Pe f t a p ra u ifqrflin t atins a n cy le fo he parat s an embad s 1 therein ea rmi n t e i :dr u ne int o l i m r 9! dr insfisaidg t ueltfe d ns m ansa s l e t p l nsi m an i and for; causing said controlling means to reduce l d 'Qitheap a s or, tia ab in y e ite the an ara sy em o the e n imeansr rorc s n z ircui at n poi o i rnotorgso thatjit drives said fueijeeding-means and said air supplyingmeans andjonso changing; the condition oi said circuit as to cause said controlling rneans to reduce the pressure and the }volume of I the air Sup lied to ,the, fuel bed; sg that said u l is e 0513 et rtx t h nt burning rate of thefuel lbed thereon ,and where- ,by the fuel bed builds upin depth and "increases its resistance? to the passage of air. therethrough g toim r e e p t ereo ea eansl 'e .ative under the action o'fnthe'increased pressure t n ii nfi si srth p rcui catfi i a t m nimaid m er; andaz pa sth cirjcuit at the first mentionedpoint andforagain changing the :cond'ition, of said circuitfwith 1 re- *1 i e t m th i l c r c l Re eate ns, s

t t itope a es t r v e a maximumv um 9 a r m e rp e sii e tame e b dzso; t ht 1 gburning rate is faster than its feeding rate of fi In, a fuel burning apparatus having burning ,Zperiolis, each constitu-ting a plurality ,of 511C08 fuel tithe fuehbedand wherebvsaid tiu el hed b own in depth d decre se i msis'tan i to thetainsupplied so thatgthel-pressurethereof offand'means operative underthe action of that increased pressureof the supplied air for operatively connecting said driving means to said fuel feeding means and to'said air supplying means at another point and fordisconnecting said driv-' ing meansfor said fuel feeding means and said 1 air supplyingjmeans at the first mentioned point andlfor changing the condition of said circuit soas to cause said air controlling means to pro- ,vide a maximum volume of air underpressure to the fuel bed so that its burning rate is faster than its feeding rate and whereby said-fuel bed, burns down in depth and decreases its'r'esistance to the air-supplied so that the DIBSSHIBI thereof is decreased to that whichinitiates a succeeding v b minsper df 1 8. Ina fuel burning drivingsaidafuel feeding means and said blower, a; duot gfor conveying air from the blower to the jr etortQmeansinsaid ductl and operable to con: V trol the ivol u me of 'yair;passing therethrough to at 33W" @Q I ffl t M dibY t e. low essur of theair in theduct on onepside of saidcon- I H q i m an a i n v n eb i ins va ie P t ewa p sa qrin t ng a bur i cycle -:9 e apparetusa o nec n sa d dr me at on "point tas isL l' f e e me ns "e d eid lqwer a r driving the eamezw i .saf 99 1"?! ae in ,amsi q nw di s rthe P sa e oi-airthroush t d st tax the retort and whereby theair in theduct on the;

gburm'ng cycle for the, apparatusduring a burning 1 period.

t '7. In a fuel burning apparatushaving burning periods, each constituting ,aplurality of successively occurring burning cycles, the combination, ofatretort, means for feeding fuelto the retort .toj'form a fuel bed thereon, means f orsupply ing airlunder Jpressuretothe fuel bedto support combustion thereof, amotor for drivingsaid fuel feeding means and said air supplying means, a

" e a e t tha hi h nitiates-a succeedi Y eu a e s id a ing burning cycle; for

is lume. 1 a r fi der; P e su m ns o other'sidefof the control means ,builds up to a relatively high pressure, and means actuated by saidhigh pressure of air in the duct for connect- ,ing said drivingimeans at another point to said fuel feeding means andto said blower while lower pressure air in the duct ontheotherjside of said control: means, through said means actuated therebydisconnects said driving means; I therefrom at the first mentioned point and operates said control means topermit-the maxi -mum' passagetof air throughi the duct to pro"- vide aburning rate for the fuelbed that is faster than the feeding rate for the fuelthereto in the final partof said burning cycle-so that the} pressure isjreducedfthroughout .thedirct; said twolast mentioned means operating'atsaid re; duced pressure to initiate a succeedin'g burning cycle of the apparatus; i

9. In a fuel burning apparatus Ingj a V Iume oftair under pressure, amotor for ap ar t isy in periods, each constituting a plurality of succesit i i l q eiu' insr ar ins yc e th com inatio of a retort, means for feeding fuel-,to 'theretort f m a e b dt r aera ihleweri r odu I g having burning i periods, each constituting a. plurality of succesi sively occurring burning cycles; the combination} f of a retort,,means for feeding fuel to ytheretort j to form a fuel bedthereoma blower for produc.-

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