US1685482A - Steam and air injector - Google Patents

Description

Sept. 25, 1928.

J.- DOHERTY STEAM AND AIR INJECTOR 1 Filed April 24/1923 2 Sheets-Sheet 1 Sept. 25, 1928.

J. DOHERTY STEAM AND AIR INJECTOR Filed April 24, 1923 2 Sheets-Sheet 2 James 001/52 f).

' 1,685,482 FIGS...

muss mums, n (amass. mammacrim. AND! AIR nma es ATENT or star a i m Ann 2. s i s I9-.634..-232- The present invention relates to boiler and furnace construction, and has particularly to do with means for increasing the 'combustibility of fuel. H "Reference will be had at various tunes to my Patent 1 402,843, issu-ed January 10, 1922,

' and one of the objects of this invention is to provide a modification of and'improvement upon the construction therein described.

Another of the invention isto rovide in a single furnace an adaptabi ity whereby coals of different types may be burned with e ual efficacy, the invention providin means or securing complete and regulated combustion of such fuel.

Another object of the invention is to tovide means for introducing air and steam at various joints within the combustion ch an ber and no passages of a furnace or boiler in order to promote com lete oxidation of the fuel material and fue gases. It is contemplated that such steam and air will be admittedto the fire box and flue passages in regulated portions, and that the steam' will be injected transversely of the gas travel in the boiler or furnace, and that the air will have a controlled temperature.

The invention comprises, in part, the manner of introducing and heating air to be supplied to the combustion chamber, in part, to the manner in which steam is introduced therein, and in part, to the. arrangement of the air and steam passages and of" the steam supply means within the'fnrnace structure.

These objects, and such other objects as will hereinafter appear, are attained by the construction, combination and arrangement of parts now to be described.

The acmmpanying drawings illustrate the preferred form of the invention, and it will be manifest from thedescription herein that the construction and arrangement thereof may be varied without departing from the invention. Y

In the drawings:

Fig. 1 is a perspective view of a typical sectional. water-heating furnace with the side wall broken out and the interior parts shown in i 'ertical'and oblique sections; Fig. 2 is a transverse section adjacentthe front water curtain therein;

- Fig. 3 and Fig. tare details of the steam pipe construction, and n Fig. 5 is a plan view of oneof the sections of the air duct forming members.

Like reference characters are used todesignate similar parts in the drawin and in the description the, invention whic follows,

The furnace shown thedrawing is enlly of t s yp a hat i us a in my patent referred to above, and com rises front a k a r-c n ning sec ion 1 and and a p u a ity o in ermed Wa containing sections, 3, 4, 5, 5' and 6. all of which sections have the same eneral external configuration and areadapted to be clam d or otherwise secured to one another, ad is usual in sectional boilers, The water spaces of each intermediate section and those in the front: and back sections 1 and 2 are in communicat on, as is also customary in boiler construction. i i

i In assembled relation, the several sections referred t fi P o id the fire h x and h flue pa f r xpo i the qui it ur ace for the transfer of heat from the combustion vgases to the water withinthe water s aces.

To increase the surfaces ex osed to the heated gases of combustion as welyas to augment the water covered surfaces, sections 3 and re substantially of a T-shane in cross section, tie depending portion, or the stem of the T, being shorter inthe latter sections. sections 3 and 4 form the roof or crown of the fire box which has its greatest vapor ca acity immediately adjacent and in front o section 5 which comprises a cross member or bathe containing a water space and depending considerably below the crown wall'of the'fir Said section marks the rear limit ofthe upper part of the fire box and providesa water curtain intermediatethe front and rearpor- 'tions thereof.

After combustion gases ass through the I flue spaces in section 6 and etween sald'section and the adjacent sections 3 and 5,

gases are passed forwardly through horizontally directed side flues 7 and then rearwardly rough a ho i ontal c nter flu 3 ar ange p a l to fin s 7 o the ake-eff an c mney,

which latter are not illustnatedy The flue-.2)!- rangement described is at new and is not essentialto the success of t e invention, about to be disclosedfoi other fluetarrangements may be employed without decreasing the'efficacy of the invention.

The bottom of the firebox comprises a per forate up draft grate 9 and is ordinarily arranged in parallel relation to the-crown wall and hence is substantially horizontal. Its rear end terminates withand abuts upon the vertical portion or a bridge'\\"all or banlclO which is upwardly inclined as it approaches thelowermost and depending section of secfaonpr section 5? at the rearofjthe furnace.

' Coal is supplied in the usual manner through a feed door'in the front section 1 and air admitted to and beneath the fuel bed upon the grate 9 by'an ash pit door also dis- Jposed in'said section 1 and at the bottom thereof, The air admitted through said ash pit door, of course, constitutes the major portion of a'iremployed in obtaining combustion ofthe fuel in the fire box. M i I have designated the water curtain of sectioii;5j by the ordinal 11. The loweredge thereof extends transversely and horizontally over the rear part of the grate 9 and fuel bed, occupying a level "which issomewhat "'nf earer to the gratethan was crown wall, and "in this position, as in Patent 1,402,848, it cooperates with the fuel bed directly below it, to form therewith asomewhat restricted passa geway or throat through which the fire box opens into. the'fiue space at its rear. Sub- 'stantially the entire volume of fire'gases developed in the furnace flows through this pastil sageway which extends across the furnace with practically uniform vertical dimension. As in the patent referred to above, a duct substantiallycoextensive with the water curtain V 11 is provided, saidduct being'designated by the ordinal 12, and is substantially coincident with the lower edge of said water curtain. Atmospheric air is admitted to said duct through appropriate damper-controlled inlet openingsflil in the side legs of section 5, as shown in Fig. 2 and such air is discharged from'and distributed through a plurality of uniformly spaced and downwardly directed exit orifices 14 opening upon the lower side of duct 12, and therefore, in the direction of the fuel bed. Such air flows into and through said duct and its orifices because of the chimney suction which sufhces to produce a vigorous discharge through the row of orifices and because the air path through the grate 9' ismore or less obstructed by the fuel thereon. .The velocity is so great as to cause the air to penetrate .the throat passage above referred toand seemingly to impinge against the subj'acent bed of fuel, creating an extraordinary mixing effect and turbulence in the fire gases at that passage which is manifested in practical operation by a'sheet of lividlwhite flame extending directly from the water curtain 11 to and through the horizontal hues of "theffurn'ace. 1

,walls.

nient of water sections of less vertical'dimensions, as indicated by theuse. of sections 4, immediately in front of the Water curtain 11 contained in section 5, increases the gas space adjacent said section and materially assists in the securing of awhirling of the generated .fuelgases, causing most intimate mixture thereof and of the supplemental air admitted by duct 12, whereby substantially complete combustion of such gases is obtained.

The general construction of section 5 has not been modified over that disclosed in my earlier patent. The upper and front portion of Water curtain, 11 is completely protected by a vertical tile fire-wall15 contiguous to the water curtain 11 at itsfront, and said wall is maintained 'in position by resting upon the exterior upper surface of duct 12 and bycontact between a portion of its upper section and the enlarged portion of theside legs of the furnace adjacent thecrown wall. V

combustion chamber through the duct 12, passes between a series of teeth 16 formed along the loweredge of the water curtain 11 and providing therebetween the exit orifices. 14, said teeth. being of substantially equal size and all containing Waterfrom the water curtain 11. The duct 12 is completed by resting upon teeth 16 two L-shaped members 12 which may be described as abutting channel bars l1aving..af1'ib.17 of increasing width as the side ofthe section "5 is approached.

The spaces le intermediate the teeth 16 are substantially of the .same width as the teeth The atmospheric air as it is admitted to the v Ill) themselves but their otherjdim'ension is 'grad- 1 I uated by rib. 17 so that while air is delivered .to the fire box in closely adjacent and uniformly spaced jets or blasts, s uch jets are of greater cross section as (in one dimension) the center of the fire box is approached. Such an arrangementinsuresadmission of air in equal volume through each orifice 1a and tends to prevent localization of the air supply-at theorifices adjacent the section side as it is jetted into the fire box is mainly clownwardly and slightly forwardly; andaturbu- The direction of theairgmovement combustion cha'i'nber issuch as to disturb the i v general direction and movement of the-conibustion vapors. The. wall 15, being struc;

amuse turally separate from section 5, is entirely free to expand and retract under thermal changes which occur inthe combustion chamber of the furnace without injury to itself and without imparting strain to or upon the metal of the water curtain proper or to the Wallsof section 5.

' It is well established, and equally well evidenced by a number of patents which have been granted, that the admission of steam, if it is properly legulated, to a fire box in order that it may comingle with the combustion gases, has a salutary eflect upon combustion, rendering it more complete and increasing the volume of heat units obtained. So far as I have been advised, none of the devices which heretofore have been presented, has caused the proper comingling of thesteam with the combustion gases, and therefore the devices have been failures or partial successes. It is also a tly demonstrated that the admission to the box and fines of supplemental air, in regulated quantities, and with proper conditions of ingress, tends to increase the combustibility of fuel'n'iaterial, and permits of complete oxidation of the carbon thereof within the walls of the furnace, doing away with the loss of heat resultant from partly consumed fuel va ors or gases, and overcoming smoke nuisances. I will now describe my improved methods of admitting steam and air, to a furnace whereby to cause proper corningling thereof with the combustion gases thereof. Such description willalso include the means Wl'iieh I have employed whereby such air and steam may be admitted at various stages of fuelcomhustion with the combustion gases and cat'ise their complete oxidation and maximum heat'development.

, I have found, from actual practice, that in ccrtain'classes of fuel, air which is admitted through the updraft grate 9 and through duct 12 in section in which is formed the water curtain 11, is insuilicient to provide complete combustion of the fuel, and the gases generated by such fuel, and such gases reach the flue spaces rich in uncombined carbon and other combustible products which may be made to ignite and roduce additional heat, if additional air is admitted at. the proper point in the combustion space. To overcome this condition, immediately adjacent the rear section 2 and intermediate said section and section 6 through. which flue spaces are arranged, a section '5, identical with section 5, is pmvided. Air there admitted is adapted to be thrown vertically downward and slightly forward againstthe inclined top of wall in order that it may quickly mix with the onrushing current of heated gases endeavoring to reach the horizontal titles 7 and 8 above. I It will be noted that gases which ass under'the water curtain 11 willattain a high sontally through duct 12.

"curtain l1 and throu h the restricted throat thereunder. This being true, atmospheric air admitted through section 5* will have considerable velocity, enough to cause it to impinge and agitate and rapidly comingle with the heated combustion gases. Such portions of the combustion gases as have had insanicient intermixture of oxygen to be completely consumed in the fire box and flue space adjacent thereto will take fire adjacent the rear flue space 6 and in the horizontal upper fines, thus increasing the heat values tobe' transferred to the water in the spaces about these fiues. It is, of course, contemplated that the openings into ducts Hand 12' will be damper controlled.

To convey a volume of steam to the combastion chamber and flue spaces in order that the steam may be decomposed into oxygen and hydrogen or otherwiseaid combustion and increase the value of the burning fuel, I provide a pipe Which is bent to pass from the to of one of the furnace sections, preferably t iat'of section 5, downwardly and hori- A lurality of vents or openings are arran upon said pipe, coextensive with the duct 19, in order that steam may escape therefrom in a finely atomized condition. The openings of said cent are preferably in a sin le row and downwaldly' pointed and may in so disposed as to coincide with the exit orifices 14. A valve (not shown) may be placed at any convenient point upon said pipe 20. ,Said pipe 20 is'continued out of and be yond duct 12 and passes horizontally under the updraft grate 9,, where a plurality of o nings or vents similar to those described a ve are arranged in the top surface of the pipe. A second valve (not shown) may be provided upon pipe 20 at any convenient point intermediate its two horizontal sections. In the arrangement thus described, steam is finely divided or atomized before sslng into the combustion chamber. That which is released in the duct 12 passes therefrom in intimate mixture with the air admitted through said duct and impinges the burning! combustion vapors 1mm above while moving in a vertical downward direction forming what may be aptly termed a curtain of vapor across the restricted throat passage beneath water curtain 11. The steam so discharged into the combustion chamber has equal or greater velocity than the air'with which it is mixed, and immediately comingles with the combustion vapors, creating great turbulence therein, and producing immediately changes r n which ase the combustibility o the gas mixture.

I Steam'va 301 dischar ed verticall u )ward bet, behaves in the samemanner. as thefsteam which is admitted into the duct 12,: It too is mingledwith air. This 'may become part of. the curtain of vapor previously; adverted to. The perpendicular. flow ofsteam-vapor fronrabove andfroni below the'fuel bed .differs from the steam flow produced by other devices, so far as I am informed, in that'none of these otherdevices secures proper and intimate admixture of the steam vapor and the combustion gases, and 110% provides means forcreating a steam or vapor curtain through which the combustion gases must necessarily pass on their journey to the flue passages.

- In the rearwardly disposedsection 5 I have also provided means for. atomizing steamlvapor, and allowing it to comingle with the air admitted through said section, for the .pipe 21 passing into duct 12 in section 5* is connected with pipe 20 to receive steam therefrom. If required, a valve may also be placedupon pipe 21 at any convenient point. a a

-An additional supply of steam may be employechwithout admixing such steam and air, through the agency of pipe 22, valve controlled but valvenot shown, which pipe is disposed nnmedlately ZIdJilCeDt to and rear-.

ward of the rearmost of sectionsi-B above the fuel bed. The vents or openings for the discharge of steam therefrom are, preferably disposedupon the under s-idethereof in order that the steam discharged therefrom will driven downwardly into thefvaporsbeing generated upon the grate 9 and increasethe whirling movement of said vapors between thev fire bed and crown wall. Each of said pipes, 20, 21 and 22, may be provided with means whereby to cut oil the flow ofsteam adapted to'be; discharged therefrom,-just as each of sections 5.has a damper for the con trol of the admission of air thereto.

. A fire is begun in the usual way in my furnace; The portion of the fuel adjacentto section 1 takes fire first. That portion adjacent section 5 cokes more'rapidly because the gasestherefrom comingle with the airand the steam admitted from section and pipes 20 and 22. The gases pass, under the Water curtain lland into the combustion space at the rear of the boiler where additional steam servation of combustion conditions within the fuel ch amber and of the smoke dlscharged from the chimney. Instead of the yellowishwhite and sooty flame which is ordinarily present in most boilers and particularly so with certain kinds, of fuel, there should be fdeveloped,rapidlyan. incandescent flame indicative of,admixture with the fuel gases .of ;a sufficient supply A of; oxygen". Tests] show greatly increased heat, ,both ,in volume and in .temperature.- lheefiect produced is notunlike that of the Bunsen burner; where air and gas may be mixed in order to',compl etely consume thecarbonparticles within the gas,

doing awaytwith, un consumed particles. producing both ilhuninationand carbon deposits.

;-The additional portions ofair, together with fireworks toivardthefront. of the furnace and fully consumesthe-fuel, leaving only a finely disi ashgw y o s The arrangement ofthe several. sections of the boiler may be Tvaried .atwill, and I do not want to be. limited to-either the particular constructlon; or. the particular, arrangement herein shown, for the essence of theinvention is not any, particular v and specific construction of theboiler, itself, but is the arrangement of air ductsin .properjpositions'to insure more-complete -.combu stion, andlin the mannerof admittingsteam to theboiler to obtain a proper admixture and comingling of such steam with the combustible elements of the fuel gases. ,Ofcourse, with respect to the employment of supplemental air, I have provided; the samegeneral means for insuring admissionof such air, and for obtaining its admissionat a proper temperature, as I provided in prior patent, hereinbefore frequently referred to.

It is quite manifest which is given here that the water curtain and other features of section F could with equal facility be nadea part of rearvend section 2 without departing from the spirit of invention or modifying the eificiencyof the device. i t lVhatI claim as new and desireto secureby Letters Patent oftheUnited States,is: Y 1. An air and steam injectorfor use furnace or the like, comprising an air duct provided with air-passages of graduated and increasing sizeas the center of the furnace is approached whereby an equal volume of air is distributed from each of said passages and transversely of the direction of flow of combustion vapors in said furnace, anda steam supplying member provided with a series of equidistant-1y disposed orifices adapted to discharge equal, volumesof steaminto each of said air passages. 1

,2. A furnace having. a fire boX, a grate, a water curtain, and. a bridge wall adapted to form a transverse restricted passageway into the rear, portion of the firebox-and between ntegrated; completely exhausted from the description 7 i in a admitting air to said furnace from the side thereof and for distributing such admitted air thereacross to form a curtain of uniformly mixed steam and air.

3. The combination as defined in claim 2 and in which said means for admitting air comprises a transverse air passage associated with the water curtain, the transverse air passage having graduated apertures therein, and in which said steam admitting member comprises an apertured pipe positioned in said transverse air passage and designed to discharge steam into said passage to become mixed with the air therein before the discharge thereof through the graduated apertures.

4. The combination with a furnace comprising a fire box, and flue, and a grate in said firebox and designed to support material in combustion, of a bridge wall against which burning material is designed to be banked, a water curtain depending from the roof of said firebox and in advance of said bridge wall forming a restricted passageway across said firebox, means for discharging a mixture of air and steam from a sectional portion of said water curtain, and means for discharging steam upwardly through said grate in a region directly beneath said water curtain whereby a mixed curtain of steam and air is produced across said restricted passageway. v

5. The device described in claim 2, and having means for admitting steam below said restricted passage.

JAMES DOHERTY.

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