US1267760A - Liquid-fuel combustion. - Google Patents

Description

J. GOOD. LIQUIDAFUEI. COMBUSTION. APPLlcATmN mep MAR. 244, 191s.

Patented May 28,1918.

3 SHEETS-SHEET l..

LIQUID FUEL COMBUSTION. APPLICATION FILED MAR. 24. 191e.

Patented May 28,1918.

3 SHEETS-SHEET 3.

larly consists in a method of burning such LIQUID-FUEL coM'iaUs'rION. J Y

To Hamam t may concern:

Be itxknown that I, 'JOHN GOOD, a resident of the United States, residing in Brooklyn,

' tion generally 1 l`'New Yorllr, have inventedI the followin -described Improvements in Liquid-Fuel omi bustion.

Y My invention is an improvement inthe art of burning heavy liquid fuels such as kerosene, petroleum, lsolar oil', fuel oil of commerce, and the like, and more particuliquids accordin to the principle of combusentiiied as-surface or flameless combust1on,=and provides a means for creating a blast of combustible mixture containing such liquid fuel, which ignitescold v and burns with a so-.called flamecap at a de'- sired andv predetermined distance from-the discharge nozzle'or place of mixture, as-forV example upon thesurface of a bed ofrefractor-y bodies as commonly usedtof 'establish `the locus of combustion 1n the vsurface com- 'bus'tion" art, the said mixturebeing adapted to rmiintainsuch-combustion substantially without. ame'and to all eifects and purposes the same as heretofore commonly accomyf `plishedonlyby the use of combustible gas-` yao eousmixtures.` l A I'lam aware that it has been proposedto burn asprayof liquidjfuel. in a amecap determined by the surfaces of a bedof refrac- `toryloodiesjor VOthe rwise,'but in such cases nd mea-ns of creating the spray the method -fhave 'required the establishment pf'al high temperature in the bed as a necessary-'prey liminary to the combustion bf the liquid, or

.- the liquid Vfuel (of volatile character) fhas first been required to be converted into vapor or gasepus' form before' its discharge'into the bed, 'fantino' apparatus has my' knowledge .yet been produced possessing `the practical. andfcommercial advantage ofinstantignitij bility when cldfnor thefurtheradvantages and conveniences'which the' presentinven-' 'tion provides.'

Sultsliy Y autori ratiof.regulation 'maintenance l.ofi vv ftrue andV correct proportionsof the liquid .;,divergentfrecovery sectin marked", the,

oth-,ast internal-diameter; Y1idricaljforja ,short distance b e--f` vtween i'sevlzftions' inY order tofaccommodatethe v lplosive mixture-Wheel) combustion can bep j need Aw1th: the least` invention 'further contemplates th and f @Onsttungithe combustible, or. ai..

manipulation andligvithout'--requirngjskilled Specification of Letters Patent.

"lementary to; the; methodfa'nd means liquid 'fuel-'toproduce'thesel're- Y v dudes-'or consists of-a Y enturitube of which heg-@relatively abrupt convergent entrance' vsetaion'isjmarked 5a -andthemore gradually-v -105 f various,y degrees ,off

'- ratus.

the drawings herewith, a as hereinafter fully explained and more particularly and Patented May 28,' 1ers. Application mea Maren 24, 191s. sriai No. 86,455:

attendance to operate and control the appadefinitely pointed outv in the appended' claims. In the accompanying drawings--V Figure l is a partly sectional and partly elevational view of one form of my invention;

tal section, respectively, of `a modified form of elbow tting for the .blast nozzle. Fig. 7 is a partly sectional and partly elevational view of a modified form of burner Fig. 2 shows a modified form of the burner illustrating also the -proportioningappa- -ratus each of these figures the combustion; y l

odies or balls of alundu'mtor4 otherv Vretracto'ryfmaterial but the said surface mayl j locatin surfacejisconstituted by a bed-of round also be -formed in' other ways known tol be suitable forthe purpose. The bed ofjballsv ,is contained bya support l, ofsuitably refractory material, and -of any desired form and construction,'and within or associated with this support and in heat-receivingrela'- tion to the bed' of balls or'the exhaust from them, is an air passage 2,' supplied with Vair 'l livered by the blower through the passage 2, and becoming highly heated therein when the' ap aratus is in action, passes thence by pipe 4 irectly to the blast nozzle- 5, which for "of th'e. suplport with, its connections in: rear convenience, is mounted inanupright wall -from any suitable source such as the'power- A-drivenblovver illustrated at- 3. 1 rEhe air defuel nozzle 6. The latter is threaded laterally into the cylindrical throat section so as to project slightly into the passageway through it, being thereby adapted to discharge the liquid iuel as a spray which thoroughly irnpreg'nates the a'ir stream. The nozzle t3 taires its fuel liquid through the cock 'l roin a constant-level liquid receptacle 8 thelatter being supplied by a pipe 9 from a larger source of tuel l0 placed at a higher level so as to leed to the receptacle by gravity. The said receptacle 8 niay bea float-controlled liquid supply chamber such as cornnionly used in carbureters for gasolene engines, and is provided with a needle valve ll to give close adjust-nient of the liquid delivery through the nozzle l5.

ln the construction oi llig. l the blower is preterably operated to deliver air to the burner nozzle at a pressure oi somewhere between one quarter oi a pound and tour pounds and the Venturi tube is designed Twith reference to the volume of air so delivereo to produce very considerable rew duction of pressure or relative vacuuin in its throat, This reduced pressure being inuch less than the pressure atznos aheric) acting on the surliace oiC the liquid in the receptacle causes the discharge of the liq uid lirorny the nozzle 6 so that there issues the large end or the Venturi tube a blast oi combustible mixture consisting et air and liquid fuel in iinely divided torni` rllhe proportions orp the air and liquid are those ol an explosive mixture and the subdivision of the liquid therein is so line, resulting iroin the relative vacuum and high relative velocity in the Venturi tube, that notwithstanding' the non-volatility of the liquid ituels employed, as l have discovered, it niay nevertheless be ignited cold, that is to say, before the air has become heated by the passage 2 and Without the aid of heat otherwise applied. VFor this ettect it is essential that the combustion end oiE the vJenturi tube be not remotely separated from the bed and that no material part or pasi sage intervene between the venturi and bed upon which the nely divided fuel may collect by irnpingenient so as to torni a drip, that is to say, the spray developed by the venturi must be allowed to'blow freely therefrom to the bed Without interference by lateral conlining Walls which by collecting and separating the liquid prevent ignition, For this reason it is preferred that the orice or the burner be constituted by the end nozzle 8 be regulated "with nicety which can be readily done by the needle valve ll above referred to. By the adjustment oit this valve when the blower is in operation, the critical proportion in which the blast nozzle vvill ignite cold can be easily found. Regulation olf the liquid delivery troni the nozzle 6 can obviously also be accomplished in various other vvays.

rlhe blast mixture is ignited by placing a lighted taper or a bunch oiha cotton Waste on top oi the bed of balls and then starting the blower. lllie ensuing combustion is initially accompanied by soine darne playing up from. the bed but presently and as the bed becornes heated, the 'darne disappears and the balls beconie and continue in a state of high incandescence without appreciable darne. The air delivered to the Venturi blast nozzle thereupon acquires a high temperature by its passage through the duct 2, and cori respondingly facilitates the combustion by vaporization Within the nozzle, but such heating of the air is not essential igor all purposes. Prc-nipt vaporization is also promoted by t e heat absorbed by the discharge end of the tube and conducted back through its nieta-l Walls to the throat or the venturi which point it is roost edective to produce vaporization because of the local pressure depression existing at that point.

ln the orrn of Fig. 2 the Venturi nozzle is disposed horizontally -in the upright Wall of the support l and the recovery end 5b ol' the venturi proper is provided with a short, full diameter extension which curves slightly downwardly at its extreme end or orifice so as to direct the blast against the bed. This extension should not cause such precipitation of the liquid upon the entended Wall as would give rise to dripping oi the liquid and prevent ignition, the length and curvature or the extended part being slight. "lhe liquid nozzle l2 in this 'torni is inounted in the burner longitudinally and so as to spray on the anis of the tube at the throat, the edect being otherwise the saine as in the torni ot Fig. l and producing a homogeneous line mixture of the liquid and air and also igniting and burning in the saine Way as above described. Air and liquid are understood to' be supplied by the saine nieans as already described, the air becoming heated alterV combustion has been establishedll YConductionciv heat from the orifice of the blast nozzle to the throat part of the venturi is in this' case specially promoted by supplying` the exterior of the nozzle with a series of longitudinal ribs 13 (lig. 3).

yThe cornbustionat the bed can be regulated by controlling the speed of the blower, or changing the throttle 14 between the blower and the burner, Whilecorrespondingly adjusting the liquid supply to maintain proportions, but of course always lreeplill lig@

tended lace. When the combustion'isto be -at diiferentelevations in the ing the velocity ofthe blast, higher than the rate ofliame reparations through it and so that the c vn1 ustion will -lalize at the instoppe it is well to close the cock 10a in the mainfuel line before discontinuing the air supply in order that the fuel pipe and partie arly the fuelnozzle 6, may be cleared of residual liquid which might subsequently carbonize from the heat of the burner and clo the spray orifice.

or automatically maintaining the prop ortion of liquidfuel and air for dilerent rates of combustiommyvinvention includes also the proportioning apparatus illustrated in Fig. 4 and which maintains the propor. tions fixed and correct thro hout -wide rangesandso that they are not ed by change of temperature of either theair or the liquid.' apparatus air supplied from the blower, the ,same being the whole .I

supply that goes to the burner, passes underV the control of the throttle 14 through a spee -cial passage formed by a bushing 15 and acts therein to liftv against gravity, andvsustain a eontrol body 16 which normally rests by gravity upon the bushing and to close the passage. The body 16 is'ixed on a stal 17 appropriately guided for true longitudinal and vertical motion passage and its lower end-is con-` nected to a dash-pot 18 to steady the movement and prevent fluttering. Through the cross-arm 19 at the upper end ofthe staf the air sustained body 16 operates a tapered meter-ing pin 2Og1v1ng 1t dierent positions i in the restricted outlet hole of theliquid receptacle 8, according to the elevation of the body 16 and hence according to the vvolume of air passing between said body and its seat 15. The outlet hole referred to intervenes between the liquid supply and an outlet, nozzle 21 which has its discharge.' opening inside of the casing 22, above the control body and hence .where it is subject to whatever pressure condition is determined by the weight of said body or by its tendency to return to its seat upon-the bushing 15. Inasmuch as the surface pressure in the re?" ceptacle 8 is equal yto the air pressure below the body, by virtue of the pipe connection 23, the liquid is 'thereby caused to flow through the hole and the outlet nozzle 21 and at such rate as is determined by the extent of protrusion of the 'tapered 2O in thre said hole. The shape ortaper of the pinois correlated ,to the'range' of movement vof the body'16 so, that such rate ofliqui'd s ',taining constant-'propgrt air for all l'of-'tire lb owen' Such cor-r this broad feature being an important part relation-to the inl'ow of the air, thus mainiiwalways bears' afpredetermined or fixedns of liquid and relation v.between pin? body can be established inl various ways to Vaccomplish" the results stated; in 'the p pesent casethe has -a straight or conical taper and the bushing or seat 15 of the air body 16 is given a special curvaturedesigned tol control the Ielevation of the body so as to accommodate' thelmown lcharacteristics o^f variation of flow of liquid' from nozzle outlets, or in 'other ways. TheV gravity-controlled body is preferred because of its constant uniformity A of-action,`and with gravity control vthe pressure condition above said body will of course be constant for all values of air inilow. The

' seat 15 can be threaded in the casing 22 as to theY restricted voutlet it controlss The i liquid discharged by the nozzle 21 and measured by the metering in' accordance with the air flow, squirts into the funnel-shaped receiving leads to the .liquid nozzle 6in the Venturi nozzle 5 and such liquid moves through the ipe, by the eiect of the lower pressure existing at the throat of the Aventuri. The liquid is thereby effectively sprayed into and end of a transfer pipe 24 which mixes with the air `of the venturi', quite vthe .v

sameasinthe forms of Figs.' 1 and 2 and producing the'same kind of blast mixture which'is ignitible 'cold. Such air as hap-v pens to oe-drawn through the .transfer pipe with the liquid is measured air, being taken` from thevcasingabove thebody 16 and assists in the latomization withlnthe tube, without a'ecting proportions. The main air supply becomes heated after vcombustion is established, by passage throu h the also be heated by the heat of the'bed, as for example by leading the pi'pe 2 4 around fthe-air pipe 4 which, after the apparatus is in .operatiomof course assumes .a high temperature. It will be observed that in consequence of the measurement of the liquid 'bed' duct 2, as before, 'and Athe liqui may thus heated iswithout -eii'ect upon the proportions of the mixture, andy also that the degreeof heating of the air can be as high as ltheheat upon the hydrocarbon since the entire mixture is projected onto the combustion bed. It will therefore become apparent that'the proportionngtapparatus above de desired without trouble from anyv effect of scribed can be'lconstructed in other ways `within this ventin. to carry out the rln` ciple of,measurement of the liquid an the air while in their' cold or-natural tempera ture, .whereby the subsequent heatingof onel or'both of theconsttuents of. the mixture 'cannot changethe proportions of the blast", f

bf myfinventi'on.

. 'The modification shown in Fig. iconsists 130 in the application of an elbow type fitting 25 between the blast nozzle and the hot air pipe l which ntting imparts a violent whirling motion to the air entering the nozzle and in consequence of which a substantial improvementis obtained in the homogeneity7 of the blast mixture with little added expense of construction. Conversely, the whirling motionv permits a. coarser adjustment of the liquid nozzle in the tube to produce a satisfactory thorough mixture and also allows of the use of a pipe extension of the burner or blast nozzle beyond the Venturi tube proper, if ever that should be desired without producing excessive dripping or such as might interfere with the cold ignition of the blast. This htting may obviously be einployed with any of the burner tubes hereinv disclosed.

The modie'd form of Fig. 7 accomplishes the same result as the apparatus described above, and by substantially the same means, excepting that the Venturi tube nozzle .is not employed for creating the blast mixture and that on this account two blowers are employed instead of one, one for deliver ing low pressure air to the burner and the other for delivering air at higher pressure for atomizing the liquid fuel therein. The low pressure blower is marlred 26 and taires its air through the pipe 27 and the proportioning apparatus which will be recognized as the same as that already described. A throttle 28 interposed between the blower and the proportioning apparatus controls theL air inflow. Froml this blower the air passes through the air heating duct 2 and an air pipe @l to the burner of blast nozzle proper 29 which in this form is 'merely a straight cylindrical 'tube mounted in the bed support similarly to thea several Venturi blast nozzles above described.

rEhe liquid fuel discharged from the kfuel nozzle 2l and which has been measured cold and in accordance with the air-sustained po sition of the control b ody 16, is led by a transfer pipe 2a to a nozzle 30 mounted within and close to the axis of the tube 29 from which itis discharged by the aspirating effect ofen associated air nozzle 3l also mounted vinthe tube and alined with its axis. This atomizing air nozzle is supplied with air of requisitehigh pressure (2 to 6 pounds being adequate) from the other blower 32 and the air so supplied is taken by pipe 33 from the interior of the casing 22 above the control body therein so that all of theair which reaches the burner 29 is measured air and the mixture proportions are not thereby disturbed. This high pres# sure air is conveniently and desirablyled through the heating duct 2 and the hot airV pipe 4l, so as to increase its vaporizing effeet upon the fuel. rlhe spray it produces, even when cold, is formed within the main haut/jou stream of air passing through the tube 29 from the blower 26, but near to the outlet or orifice of said tube, so that no dripping from the tube occurs. lt is essential to the operation of this apparatus and especially its cold ignition that the atomizing nozzles 3G and 3l be disposed close to., or within a few inches from, the open end or orifice of the tube 29. Otherwise the impingement of the liquid upon the wall of the tube may be so great as to preclude its cold ignition and satisfactory combustion.

.ln all of the forms above described it will be understood that the velocity of the blast issuing from the nozzle exceeds the rate of propagation of dame through it, so that the locus of the flame cap is maintained at or in the bed where the velocity slows down and substantially the same as where gaseous fuels are employed. ln each case the blast, whether of the Venturi tube form of Figs.

to 6 or the straight tube form of F ig. 7, is ignitible in its initial cold state and consequently the apparatus of this invention possesses the commercial and practical advantage of being at all times ready for instant use to give the well lrnown very efcient surface combustion edect but from heavy fuel oils. Because of the need for only one blower 4or air source7 l prefer the form of my apparatus shown in lr ig. i or in Fig. Ll, but it is evident that in producing a free and unconstricted blast of atomized liquid, which is ignitible cold and in automatically proportioning the mixture, all the forms shown herein embody the same generic principles, and also the saine essential diderences over prior art methods and structures. To safeguard the transfer pipe l from clogging with cooked or carbonized oil, it is desirable to shut olf the oil before the air, so as to clear it of any residuum. Closure of the cock 10a will cause air only to pass through the transfer pipe thereby stopping combustion and at the same time cleaning the pipe.

ico

lt will be evident that the method of burn- A ing liquid fuel above described can be carried out in various diderent forms of apparatus from that herein shown.

The term combustion locating bed, as used herein and in the following claims, refers tothe well-known refractory bed common in the art of so-called surface combustion and which serves to change the direction of the blast of theexplosive mixture and by so doing to slow its velocity down to the point where it equals or is Aless than the velocity of dame propagation through the mixture, the velocity of said mixture between the bed and the nozzle being of course in excess of the rate of-hlame propagation.

rlhose features of the invention herein described which relate solely to the maintenance of fuel delivery in proportion to yaryias ' herewith.

such nozzle thereby forming a blast mixture i of finely atomized liquid fuel and air in .the

proportions of an explosive mixture of such fuel, ignitible in an initially cold condition,l

directing such mixture in free and substantially unconstricted form from'its place of formation to and against a combustion-locating bed and maintaining said blast mixture between the nozzle and bed at a velocity exceeding the rate of iiame propagation through it, whereby the locus of the combustion is determined in or on said bed.

2. The method of burning heavy liquid fuels which consists in creating a homogeneous blast mixture of'inely atomized liquid fuel and air in the proportions of an explosive mixture of suchlfuel, directing such mixture in free and substantially unconstricted form from its place of formation to a Vcombustion-locating bed while maintaining the blast velocity between said place of formation and the said bed in excess of the rate of flame propagation throughV the mixture at such rate as will locate the combustion at said bed and then transferring heat lfrom the bed vto said place of formation of said mixture, the atomization of saidliquid fuel being of such degree of neness as to adapt the said mixture to ignite in an initially cold state.

3. The method of burning liquid fuels which consists in controlling the liquid fuel and air in the roportions of an explosive mixture of such 'quid fuel,heating said proportioned air and then finely atomizin and mixing the proportioned liquid therewith to form a blast mixture, and directing said mixture against a combustion-locating bed at a velocity, between its place offormation and said bed, which exceeds the rate of flame propagation through'said mixture, whereby combustin-locatmg ed, a blast nozzle dthe locus Aof the combustion is established and maintained in or on said bed.

4., Surface combustion apparatus comprising in combination with a combustion locating bed, an Vair-blast nozzle provided with means for producing therein a homogeneous mixture of liquid fuel and air and adapted to atomize the liquid to an extent rendering said mixture ignitible in a cold condition, and an air source to supply said nozzle adapted to maintain the blast mixture therefrom at a 'velocity between said nozzle and bed exceeding the rate of flame propagation through said mixture.

5. Combustion apparatus comprising a combustion-locating bed, an air supply having a venturi blast nozziedireaed toward said bed and means for introducing liquid fuel to said nozzle to form a blast mixture having explosive proportions of air and fuel, said air supply being adapted to maintain a blast velocity between the nozzle and the bed in excess of the `rate of liame propagation through the mixture.

6. Combustion a'p aratus comprising a combustion-locating ed, an air supply passage receiving heat from said bed and having a Venturi blast nozzle directed toward said bed and means for introducing liquid fuel to said nozzle to form a blast mixture therein, impinging on said bed said air supply beingadapted to establis a blast velocity between the nozzle and bed in excess of the rate of flame propagation through the mixture.

7. Combustion apparatus comprising a combustion-locating bed, a Venturi blast nozzle directed toward said bed, an air source adapted to discharge initially cold air through said nozzle and means for intro- 'ducing liquid fuel into the throat of the Venturi tube in proportions producing a blast mixture which is ignitible in a cold condition.

8. Combustion apparatus comprising a ombustion-locating bed, a Venturi -blast nozzle connected to means to supply it with air at a suitable pressure and directed toward the bed, means for introducing liquid fuel Vto the throat of said nozzle and means for applying heat to the air and liquid fuel supplied to said nozzle. v

' 9. Combustion apparatus comprisin a combustion locating bed, a Venturi last nozzle directed toward the same, a liquid supply pipe connected to the throat of said venturi, through which liquid fuel moves by virtue of the pressure depression existing at the throat of said venturi, a source of'liquid fuel for said liquid pipe, and

means for forcing air through said blast nozzle to create a blast mixture between said nozzle and bed exceeding in velocity the rate ofiiame propagation through it.

10. Combustion a paratus comprising a rected toward the same and means supplying air thereto adapted to create a velocity of the blast mixture exceeding the rate of

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