US1242114A - Apparatus for burning explosive gaseous mixtures. - Google Patents

Description

c. E. RICHARDSON; w. B. Euls'oN @L H. L. READ. APPARA-TzUS FOR 4BURNING EXPLOSIVE GASEOUS MIXTURES.

APPLICATION FILED NOV123. ISIS- Patem-ed om.. 2, um',

2 SHEETS-SHEET I.

. Attest:

` c. E. RICHARDSON, w. BJEDmsoN @I H.-L.YREAD. APPARATUS FOR BURNING EXPLOSIVE GASEOUS MIXTURES.

APPLICATION FILED NOIl.23.19\6. ,1114. Pawnee oet. um.

2 SHEETS-SHEET 2.

Ink

\L I I h Inventors.' I

jfBY' 2;... f l .,4

@ATTORNEY Wl TNESSES:

1 s PATENT onirica,

' CHARLES EL.`B1CHAR'DSON, ,OF YHORK, WILLIAM ARTON EDDISON, OF IBVINGTON,

' AND HENRY L. READ, YORK, N.Y., A SSIGNORS T THE SURFACE .COMBUS- "non COMPANY, or new To all wkomt may concern:

Be it known that we, CHARLES RIGH- AansoNf, vViLLiAM BARTON EDDISQN, and HENRY L. READ, citizens of the United States, residing, respectively, at New York city, county of New York, and State of New York, Irvington, Westchester'county, New

York, and New York city, countyof Kings', New York, have invented certain new and useful improvements in Apparatus for Burning Explosive GaseousMixtures, fully described and represented in the following specification and. the accompanying drawings, forming a part of the same. t

This invention `relates to apparatus for' burning explosive gaseous mixtures. The

invention has to ,do more particularly with the means for discharging the stream of `mixture tobe burned; and aims generally to reduce the pressure under which it is necessary t'o supply the explosive mixture to thediseharge tubesv or nozzles, to increase vthe range of heat production or amount of mixture burned with a limited maximum supplypressure, audio avoid the danger of blackflashing through the supply passages under any operating conditions but especially when operating with the mixture supplied under relatively low pressures, 'and also to provide a burner tube or nozzle having an approximately constant pressure# capacity characteristic under varying sup- 'plyl pressures, such a tube Aor nozzle being desirable with some types of mixture supply The invention relates to that type of ap` paratus in which coi'1 tiiuious and localized eoiubustion of' au explosive gaseous mixture is 'secured by causing the mixture to flow from a discharge passage or orifice with a velocity greater than the rate of propagation of iniiammation of the mixture in order to prevent backflashing,` and then causing the mixture .to spreadout with rapid freductionof its flow velocity, and burningthe mixture .where its fio'w velocity equals the rate of propagation of inflammation of the mixture. The spreading of 'the mixti'lre may becaused by bafiiing moans consisting of a porous and permeable bed of suitable hi'ghly refractory material, vor other suit-v .able lmeans, located close to the discharge orifice so that the stream is caused to spread immediately as vit leaves the orifice, or the Specification of Letters Patent.

YORK, N. Y.,' A CORPORATION 0F NEW YORK. i i

arranarus son BURNING nxrtosrvr. easnous mx'runfns.

Patented oet. 2, 1917.

i Application led November 28, 17916. Serial No. 133,086.

mixture maybe permitted to flow from the orifice as `an unconfined streamwhich in1- pinges against a baffling means spaced off at a suitable distance from the discharge orifice, or the rapid Vspreading ofthe mix' ture may be caused in other ways.

` By such continuous and localized co1nbustion of explosive" gaseous mixtures, ex-

tremely high tempetatres are' developed,

Whilethe main Vportion of the mixture is.

flowing on, unburned, to be consumed at the surface or place where its flow velocity has been'i'educed to the rate of propagation of infiammation. This back-creeping of com-4 bastion, which is a totally different thing from back-flashing through the body of the stream of mixture, probablyresults from the presence of a relatively slow7 .moving thin layer or film of mixture against the walls of the discharge passage, dueto the frictional `resistance' 'exerted' by the Walls on the mixture flowing, past them'.v If the edge of the discharge 4'orifice becomes heated to a suflicient temperature, Aprobably a temperature somewhat above the ignition' temperatureof the mixture, this relatively slow;

moving film of mixture becomes ignited at such point and combustion then trav-elsbackward along the walls for -adistance and at a rate depending upon the Itemperature of lthe walls and the velocity at which-the mixture is fiowingthrough the passage. With increase 1n flow velocity ofthe mixture, the

thickness of the relatively slow moving wall4 fihn is reduced and the coolingl effect' of thefstream offmixture on such film and on the walls of Athe `passage themselves 'increases, so that the back-creeping tendency decreases-with such increase in flow velocityv of-tifemixture, and-with a sufficiently-high flow velocity backlcreeping maybe stopped.

and combustion within the discharge passage or orifice entirely prevented. ,l reven tion of .suc-h back-creeping in this way, however,means that continued operation ofthe apparatus requires a relatively high mixture su ply pressure.

his back-'creeping of combustion along the walls of the supply passage is objectionable for a number of rcasonsz IIt causes more or less rapid deteriorationofthe ywalls of the discharge passages according to `the ymaterial of which they arelliormedf; b heating the stream of mixture flowing t rough the passage, itcauscs axiavelop-v ment of back pressure or resistance to flow, which reduces the velocity with which Athe mixture is dischargcdiinder a given suppl pressure, and which is objectionable .mit

some types of means for supplying .themix` ture because of its oiect in changiiigthc proportionsl of the constituent ,gases in the mixture; and it `causes' ignition and explosion of the` slower moving .mixture in supply passages or\ chambers, when the backcrceping reaches such a passage orehamber. 4 By reducing theiveloeity of discharge, the` development` ofback-pressure or resistance to flow resulting from :the .heating of the mixture limits the reduction of supply .pressure under whichthe apparatus will operate charge passage through which the mixture and restricts the range .of operation under a given maximum supply pressure.

lt is desirable, in order to reduce the re` sistance .to iow of the mixture, that the disis caused `to movefwith excessvelocity to prevent backflashing, be relatively short, the

. mixture being supplied to such assage Y sa` through a larger passage in which t, e flow velocity is relatively lower. It is also desirable that :the mixture be discharged through a `short passage or orifice of such form that How `of mixture `,therethrough under varying pressures shallfvaryaccording to the flow -lavv of o'riices, and that. ipe resistance as a dontrolling factor onl t e flow of the mixture he avoided. VithI such a short discharge passage or orifice, the danger'of ignition of the mixture in the larger portion of the passage and backflashing therethrough is, of course, greatly increased,

both from the back-creeping of combustion' along the u'alls `of the discharge passage or orifice, and alsolby" the conduction of heat through the walls themselves.

It is the object ol the present invention to avoid such hack-creeping of combustion tion by means whereby all parts o f the vvalls of the discharge passage or orifice are pre-' of any part of the mixture `within the discharge passage or orifice, even withl a comparatively low mixture `flow velocity, and this result is secured according to the'invenvented from becoming heated tothe ignition i temperature of the mixture.

The nozzle is provided with means where- ,hy' heat reaching the nozzle and which would 4otherwise accumulate and `raise the temperature offthe Wallsl of the discharge lutidrawing mea-ns. AThe circulation of a Ematerial of high heat conductivity, if there discharging the heat to ,the atmosphere or passage or orifice unduly, is carried away with sulicient rapidit to .prevent such result, and the access o heat tothe noszle is limited so as to reduce the loss of heat and to reduce the burden imposed on the heat coo ing fluid may be resorted to -Vfor this pur vgse, but most desirably the nozzle is mae of a suitable metal or other suitable 76 is such other material, and of sufficient mass in all 'its parts which receive heat .either from the furnace chamber or from the iurduet the heat from the exposed end of the 'nozzle back to diipating means, the walls `of the mixture discharge passage or orifice should be of materialy of high heat conductivity, such as iron or other suitable metal. As such material not only conducts heat rapidly, but also rapidly absorbs heat, the nozzle is so far as possible protected from direct access .of heat by a covering of material of relatively low heat conductivity,

10 t usually a part of the furnace wall of brick,

cement or other refractory material, in which the nozzle is Set. Such material, however, because of its 4low heat conductivity, becomes very highly heat-ed under the intense heat of the combustion `of the ex- 1 plosive mixture, the whole refractory wall of' a .furnace chamber `usuallybecoming inore .or less highly incandescent. Contact of any part Yot such materiahtlierefore, with the stream of mixture issuing't'rom the nozzle .oriiice would result in 'ignition of. the

mixture at the edge of the orifice, andto avoid this, `a part of the metal of the nozzle nose immediately surrounding the orifice is 'left uncovered,the width of such .exposed portion -of metal being suicient to yprevent contact .of the issuing stream of mixture with, and ignition thereof by, the surrounding refractory Vmaterial of the fur- 12o nace wallby VWhich' the main portion of .the nozzle is protected. In the accompanying drawings-v Figure 1 is a. central sectional view of a soft metal melting furnace made in-accordance with the invention; Fig. 2 is an enlarged sectional View of a part ,of one of the mixture discharge nozzles such as shown in Fig. 1 'and adjacent portions of the furnace walls;

, Fig. 3 is. a rear end vievy of one of the nozzles shown in Figs. l.' and 2;

Fig. 4 'is 'a view similarto Fig-2 but showing a form of water cooled nozzle.

Referring to the drawings, and*` vfirst t Figs., 1, 2 and 3, the furnace structure shown comprises a bottom -wall or floor and side 'Walls 11 of brick-Work, the brick wall 11l ber .between the vside Walls.

being inclosed'within an outer metal casing v12:vvith an 'intermediate space between/the metal .and the brick filled with heat insulating ymaterial 13, such as powdered silo-cel. Carried by a suitable support' on the` top of the side walls 11, is aimelting pot 15 p which extends down into the furnace cham- The explosive gaseous mixture to be burned is discharged from a plurality of discharge tubes or nozzles 20, of which two are shown in section in the drawings, mounty ed in the side wall 11 and setto direct the jet or stream of mixture issuing therefrom against a suitable baffling means by which "the mixtureis caused to spread ont Wi'th CII rapid reduction of its flow velocity. In the furnace shown the baiiling means is spaced i from the nozzles so that the issuing streamsof mixture are permitted to .travel from the nozzles to the baffling means as `unenfined streams, and as shown the bafiing' means consists of a bed or beds 2l formed of pieces of refractory material ar- `ranged with the surface the bed in suitable relation tothe doW-nwardlyl directed Istream of mixtureso that the stream will Y ,bei baiiied ahdvcaus'ed to spread out in the desired manner. Such a bed will be porous and permeapleand will have the advantage l of permitting the products of `combustion to pass through it'vand escape therefrom be- 3 yond lthe place where lcombustion takesplace, and the combustion may take place at the surface of the bed or Within the bed, according to the size of thestream of mixfture and the velocity with which it strikes the bed. vf i A furnace of this kind may be of any desired shape in horizontal section. IThe lwall v11. Y -f 4 v i The explosive mixture may. be supplied one shown isja circular furnace,'the mixture discharge nozzles, of which there may be any desired or required number, being "arranged radially in 'the cylindrical lside to' the discharge nozzles underr the necessary pressure to cause the mixture to be Edischarged vvit"` a velocity in excess of the `frate of propagation of inlammationof the mixture. from any' suitable source orby any f suitable means. As shown, a mixing injector is provided for supplying an explosive mixture of fuel gas and air, the gas being suppliedto the injector nozzle 25 under` suitable pressure and` air being drawn into the `cmubining tube 26 of the injector by the gas pipe or mani jet, and the s and air thenpassing through l the neck o the injector and throughthe discharge ory pressure cone 27 to a supply old l28 from which branc es 29 lead to the several nozzles 20. The ini jector should be designed, and. the nozzle andcombining tube set in proper relative position, as by adjusting either one, to supply a mixture containing the gas and air in ysuitable proportions,'and the 'gas should reachthe in]ector under sufficient pressure to cause the mixture as'supplied tolthe nozzles to iow through the dischargeporiiices of the nozzles with a velocity in excess of 4the rate of propagation of iiame throughl the mixture. The manifold 28 and supply branches 29 should be large enough to permit the mixture to move therein with such comparatively low velocity as to secure a substantially uniform supply` of mixture to all of the nozzles, and to avoid pressure losses due to pipe friction. The nozzles 20 are formed each with a bore or'pa'ssage 35 extending through the body of the nozzle of a size which is most Adesirably substantially greater than the size n of the discharge orifice, and this passage ta-v pers down at the front or discharge end of the nozzle andv terminates in a restricted short discharge passage or orifice 36 which desirably has parallel Walls for a length sufficient `to cause the mixture to be discharged in the form of a solid jet or stream. The nozzle is formed of material ofliigh thermalconduetivity'; such as cast iron or other suitable metal, and is made of'sullicient cross-section or mass so thatall parts thereicol of'shall have the required-heat conducting to the furnace heat.

It is desirable to have the nozzle protected so far. as possible from direct access of furnace heat, both for the purpose of keeping down to a minimum theloss of heat through i the nozzle Walls, andto avoid vunduly/increasing the size of the nozzle to give it the necessary heat carrying capacity. On' the other hand, it is necessary, as pointed out ante, that there lshall be some extent of metal about the edge of the disclniige orifice exposedto direct access vof heat from'the g furnace chamber,.in order to prevent contact4 with the stream of mixtureof any material o f relatively low heat conductivity forming part of the furnace Wall. "Because of its 10W heat-carrying capacity, the refractory materia-l of the furnace wall, under the intense heat developed, becomes extremely hot, usually incandescent.I The exposure of any sufficient extent of the metal ofthe nozzle'about the edge of the oriiice prevents contact of such incandescent material with the mixture and avoids` the ignition of the mixture at the edge of the orifice with increase in temperature at this point and increased tendency to back-.creeping which would result from such contact.

The exact width of extent of metal left uncovered at the nose of the nozzle is not particularly important, provided it is sutileient to secure the desired result, but in order to avoid loss of heat and the necessity of providing for the carrying away of such excessive amount of heat, itis most desirably not much wider than is necessary to protect the mixture from the incandescent material.

We have usually found it desirable to set the nose of the `nozzle slightly back from the'face ofthe furnace wall in a small recess formed in the'face of the wall, with the' nose of the nozzle extending somewhat into the recess and then partly lilling in the recess abou-t thenozzlenose with a suitable refractory cement, as indicated at 40, having the cement extend not beyond the outer edge of the annular face at the end of the nozzle and forming it to flare suitably away from the path of the mixture stream. The cement should he carefully placed to form a tight joint with the end of .the nozzle so that it may not only protect the same from direct access of heat, but also by sealing the space4 between the nozzle and the brick-work prevent .the hot furnace gases from flowing in around the nozzle, although this is not'l necessary provided the nozzle is otherwise suitably sealed in the wall so as to prevent thev iow of the furnace gases past it. The nozzle is desirably formed with a tapering nose as shown having. near its discharge end projections 4l of suitable `form to provide a hold for the cement 40.

For .taking from the nozzle the heat conducted Erom its exposed portions backward through its body1 portion, .the nozzle is provided' with heat dissipating fins 42 formed on its rear end outsidethe furnace wall, such lins providing extended surfaces of sufficient extent to discharge to the atmosphere all the heat reaching them through the body of the nozzle with sufficient rapidity to prevent such accumulation of heat in any part of they nozzle as would result in tan undue increase in temperature of any such part. The fins may be of any suitable form. Flat annular tapering fins of about the proportionate sizeshown in the drawings lon nozzles made of cast-iron have been found entinely satisfactory under various conditipnsof operation, and makethe provision of lspr-'eoal moans, :Such Ias means providing a circulating Huid -for .carrying away hea-t lfrom .the nozzle, wholly unnecessary.

The nozzle may b e secured to the outer cas- 'walledinixture tube 50 provided With-a tapered nose piece 51 formed to provide a restricted discharge orifice, and a metal casing 52 .extending about the tube 50 and connected with the edges of the nose piece 51, o the space between the mixture tube and the casing being-divided by a partition tube 53 which ends short ofthe front .end of the casing seas .to provide concentric supply and retuin flow passages for water or .other cooling uid which is supplied and discharged through pipes '55 and This jacketed nozzle may be set in the furnace wall` in substantially the same manner as the air cooled nozzle shown in Figs. l to A3 the front end of the nozzle-being protected more or less from direct access O15-,furnace heat by a protecting covering formed by a filling of cement or .other part of the furnace wall, such protecting covering ending.` short of the edge of the discharge .orifice as shown and for the purposes hereinhegfore described,

It will be .understood that by ,the term explosive gaseous mixture as used herein4 is meant ,a mixture of a suitable combustion supporting gas, either oxygen alone or air or other oxygen-,containing gas, with ycombustible matter 1n a gaseous or other finely divided state in proper proportions, that is, in proportions such .that the. mixture will have the property of self-propagation of infiainmation.' For producing the highest temperature, the oxygen should .be undiluted and the mixture should contain .oxygen 11o and combustible matter in chemical com bining proportions at the time of combustion; but there may be yan excess of either the ,combustible matter or the combustion supporting gas within the limits which determine t e property of self-propagation. The mixture may be varied in this respect' according to the desired character of the products of combustion, thatis, whether it is desired that the products shall be neutral, oxidizing or reducing. Also, the mixture may of course contain neutral gas such as nitrogen, carbon dioxid or water vapor, so long as the amount of such neutral gas is not sulieient to make the mixture non-explosive. What is claimed is: I

1. Apparatus for burning explosive'gascons mixtures, comprising in comhiiuilion V with a furnace wall, mixture discharge 'im its 55 e A a veloci i nozzle set in said wall, `means for su an explosive gaseous mixture tof sai nozzle under pressure sufficient'to cause the mixture to be dlSCharged from the nozzle with a velocity' greater than the rate ofv propagation of infiammatim of the mixture, and means for 'causing the stream of mixture issuing from? the nozzle to spread out with Z of simcientextent rapid reduction'of its flow velocity, the nozthe furnace heat by material f the end of the nozzle immediately adjacent and surrounding Iits discharge orifice, such exf posed portionzjof'the endof the nozzle being of limited extent to limitthe amount' of heat directly absorbed by the nozzle while toprevent contact of the issuing .stream ofemixture with any .part of the material of low heat conductivitl of the furnace wall, and means for withdrawing 'heat from thewalls of the dischar e orice of the nozzle and from n such expose portion of the .nozzlejto maintain the temperature thereof below the ignition temperature of 2. t Apparatus for burningexplosive gase ousmixtures, com rising in combination with a'furnace wa l', a mixture discharge nozzle set `insaid wall, means for su plyingmixture to sai nozzle an explosive gaseous yunder pressure suiicient to cause the mixture to be discharged from the nozzle with greater than the `rate of propagation offinilammation of the` mixture, and

conducted. away i issuing stream means llerI causing the stream of mixture issuing from' thenozzle to spread out with rapid reduction of its flow velocity, the nozzle being formed of material of high heat conductivity and being' protected from direct access of the furnace heat by material of" low heat conductivity forming part of the furnace wall except .for a portion. of the end of the nozzle. immediately adjacent and surrounding its discharge orifice, such exposed portion of the end of lthe nozzle being of limited `extent -to limit the amount of heat directly absorbed by the nozzle whileextent to prevent contact of the ofl mixture with anypart of low heat conductivity oi'l the of sulicient the material of 'furnace wall, and the nozzle hein provided vwith heat discharging means an bein o such mass between -i-ts exposed end an heat discharging means that heat will be fromthe walls of the dis'- v4charge orifice with suiicient rapidity to .ous mixtures, comprising maintain the walls of the orifice at` all times below the temperature 'oignitionof the mixture;

'3. Apparatus fo'ii'burning explosive gasein combination with a furnace Wall, a mixture discharge Plying 'to maintain the Walls of the oriice at allv passage,

perature its! ` ture ofthe mixture,

nozzle set in said wall, means for supplyingy explosive gaseous mixture to said nozzle'- under 'pressure sufficient to cause ythe mix ture to be discharged from the nozzlewith afvelocity greater than the rate of propagation of inflammation of the mixture, hai.` l fiing'means spaced away from the nozzle 'to f cause the unconfined stream of mixture .tok 1 spread out withrapid'reduction of its-flow i y i'elocity, the nozzle 'being formed of matev75 rial of high heat conductivity and being pro#` tected from direct access of the furnace heat by 'material of low heat conductivity form" ing part of the furnace wall. except for a portion o the end of the nozzle immediately adiacent and surrounding its discharge orifice, such exposed portion of the end of the nozzle `heing of limited extent to limit thev amount of heat directly absorbed by the;v nozzle while of sufficient extent to preventpsr; contact of the issuing'stream of mixture', -with any part ofhe material of low heat lso conductivity of the furnace wall, and the ,j

nozzley being provided with heat discharg-y ing means outside the furnace wall and y-beingoof'such mass between its exposed end,- and its heat discharging means that heat will be conducted away from the wallsof the discharge orifice with suiiicient rapidity i times below 'the temperature the mixture.

4. Apparatus for burning explosive s-v eous mixtures, comprising means provi ing of ignition ci a mixture supply passage constricted atits y discharge end to form a short discharge l passage, the walls of said'discharge passage being of material of high heat conductivity, means for reducing the flow velocity'of 'a' stream of the 'mixture escaping from said 105 .and means for withdrawing heat fromv the walls of said discharge passage with suilicient rapidity to maintain the temof said walls and of the Walls of* the supply passage below the ignition tein- 11o perature of thevmixture.

5. Apparatus for burning explosive gaseous mixtures, comprising means providing y a mixture supply passageconstricted' at its discharge end to form a short discharge passage, the walls of said discharge passage being of material of high heat conductivity, means -for reducing the flow velocity of a stream of the mixture escaping from saith passage, means for withdrawing .heat from the walls of said discharge, passage 'with suflicient rapidity to maintain the temperay ture of said wav ls and of the walls of thev supply passage below the ignition temperaf and means for. limiting '125 access of heatto the walls of said discharge f passage.y 6. ppa-ratus for burning explosive gaseous mixtures, comprising means providing a4 mixture supply passage having aconisoV passage and said heat abstracting means' stricted discharge orifice7 the walls ofy said orifice being of material of high heatk conductivity, means for withdrawing heat from said orifice walls with sulicient rapidity to'- l'naintain the temperature of said walls below the ignition temperature of the mixture immediately adjacent and -surrounding lits. discharge orifice, such portion being leftA ex posed `to prevent contact of the issuing stream oi? mixture withk any part of. such protecting material, the opposite end of the nozzle being ,formed with heat dissipating fins, and the body` ofthe nozzle between its lexposed yend` and its heat dissipating fins being of. such mass that heat will he con`- ducted away from the walls of the discharge orifice with suiiicient rapidity to maintain the' walls of the orifice at all' times `below the temperature ofignition ofthe mixture.

8. A mixture discharge tube for apparatusfor burning explosive gaseous mixtures,

formed of metal and having'a supply pas sage extending therethrough constrieted at itsxdischarge end to form ashort discharge passage, the tube being providedat a point removedt from said7 discharge passage with means `for taking heat therefrom, andthe` body of the tube between the walls of .said

set our hands, in the saidfins being'of such mass as to conduct heat away from the walls of the discharge passage with suliicient rapidity to maintain I the' temperature of such walls below the tem.

peratureo ignition of the mixture.

` 10i 'Apparatus for burning explosive gaseous' mixtures, comprising means providing a supply passage having a discharge orifice, the walls of said orifice being of material of high heat conductivity, means for withdrawing heat from Said orifice walls with sutlicient rapidity to maintain thetemperature of saidA walls below the ignition, temlperaiure of the mixture, and a 'protecting covering for limiting the access of heat to the walls of said orifice; said covering leaving a narrow band of metal at the edge of said orifice exposed to direct access of heat.

In testimony whereof, we have hereunto presence of two sub-l scribing witnesses..

' CHARLES E. RICHARDSON.

W. BARTON, EnDisoN'. l imNarLeREADe witnesses i Bonsai* Q. Gambino, J rl, ,y q l '.*BnnonriiryRmon

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