US1441703A - Furnace and means for feeding fuel thereto - Google Patents

Description

Jan, 9. 1923 LMU/@3,

J. E. MUHLFELD ET AL.

FURNACE AND MEANS FOR FEEDING FUEL vTHEIRETO.

' FlLEp H815, 1918I naar s.

JOHN E. MUHLFELD, OF SCARSDALE, AND VIRGINIUS Z. CARACRISTI,

0F BRONXV'ILLE,

NEW YORK, ASSIGNORS TO LOCOMOTIVE PULVERIZED FUEL COMPANY, OF NEW YORK, N. `Y., A CORPORATION OF DELAWARE.

FURNACE AND MEANS FOR FEEDING FUEL THERETO.

E Appucati'mi filed February .5, 191s. serial No. 215,428.

T0 all whom it may concern Be it known that we, JOHN E. MUHLFELD and VIRGINIUS Z. CARACRISTI, citizens of the United States of America, the former a resident of Scarsdale, in the county of Westchester and State of New York, and the latter a resident of Bronxvil'le, in the county of llf'estchester. and State of New York, have invented certain new and useful Improvements in .Furnaces and Means vfor Feeding Fuel Thereto, :of which the following is a specification.

The present'invent'ion relates to improve-4 y ments in furnaces and method of feeding fuel thereto, the present disclosed embodi! ments of our .invention relating particularly to boiler furnaces in which pulverized fuel is burned.

It is an object of the invention to provide an improved method of feeding and mixing with air, tothe end that the'greatest eiiiciency is obtained from the furnace, and the furnace may be maintained in proper condition with facility, and without interfer- 'e'nce with the operation thereof.

l Heretofore those parts of the furnace which deteriorated rapidly were inaccessible during the operation of the furnace, and it was therefore not possible to repair or renew the same withoutputting the furnace out of use.` It is proposed in the present invention l to enable the renewal of these parts while the furnace is in use, and at the same time greatly improve the process of combustion. A further object is to provide an improved feeding means, whereby a more'perfect mixture ofthe fuel and combustion air is afforded, permitting rapid combustion to. take place, and to this end we propose in one 'embodiment of our invention to feed the fuel in separate streams independently embraced by air.

lith these and other objects in View, embodiments of our invention are shown in the accompanying drawings, and these embodiments will be hereinafter scribed with reference thereto, and theinvention will be finally pointed out in the claims.

In the aocompanyingdr'awings;

Figure 1 is a diagrammatic sectional View yauxiliary horizontally more fully deof a furnace, showing one embodiment to a stationary boiler furnace Figure 2 is a front elevation of the fuel feeding burners;

Figure 3 is a sectional view along the line 3--3 of' Figure 2. l

Similar reference characters indicate corresponding parts throughout thev several is provided a projecting mixing oven 11.

In th top wall 12 of the mixing oven, which is pre erably arched, there are provided the substantially vertically disposed Vfuel feed burners hereinafter more fully described, while in the fro-nt wall 13 there are provided disposed air feed pipes 14, having control-ling dampers 15 therein, a suitable number of these being provided, depending upon the width of the oven, and the rate of combustion required.

The floor 16 of the oven is disposed directl-y beneath the feed burners, and may be inclined downwardly from the door 17,

forming a target and deecting wall for the `.products of combustion and fuel impinged thereon, as will be presently pointed out.

Thevrear wall 18 of the combustion chamber may be inclined at its lower portion 19, this inclined 'portion being spaced from and extending above and below the target wall. The floor 2() of the combustion'chamber extends in spaced relation below the target wall to form anoutlet for slag, which may rbe removed through the door 21.

lVater tubes 22 to be heated, are disposed across the combustion chamber. This is an arbitrary arrangement, however, and other means to which heat is to be imparted may be suitably provided. 1

The lfeed burners disposed substantially vertically in the top wall 12 comprise a casing 23 in which there` may be provided a plurality (two in the present disclosure, although one or any suitable number may be provided) of channels' 24, extending above the casing, and having their lower ends at a point above the lower end of the casing. Air' said supports 32 and 33, anda nozzle 'pipe' 36 is mounted therein and extends to the lower end of the channel.. A downwardly turned fjet nozzle 37 may be inserted in the 15 pressure, steam or other suitable gaseous medium linto the pipe for induction.

Inl operation, the pulverized fuel enters throughthe nozzle pipe 35, fed bymeans 2'0 of air underl pressure or by induction produced by the'A induction jet from the nozzle 36 causing the fuel to enter at a relatively high velocity. J A combined mixture of fuel and air is forced by air pressure or induction through the fuel nozzle, 36. 'This stream is surroundedand mxediwith addi,

tional air entering by induction through the channel 24, which mixture of -fuelandair is again surrounded and mixed with addiotionaly air entering by induction through the channels 26, 27, 28. The fuel being now mixed with sufficient air for combustion and subjected 'tothe radiant heatfrom the incandescent target wall 16 burns. .The

' entering the air openingsv 14, which tends to break up .thel surrounding layer of consumed gas by causing eddiefs and permit? ting additional air to come`into intimate .contact with the partially consumedl gas in the core of the flame causing complete combustion. -The -mixture impinges against the Itarget wall x16, and by reason of the inclina# tion of the saidwall, is deiected in the directionl of the :arrows toward the inclined rear wall `19, which guides the same up wardly through the furnace. The target wall is incandescent during operation of the furnace, and causes ignitionaof the fuel.

In order to promote `the production ofV a perfect mixture of the fuel and air, and to prevent the impinging of the fuel upon the target wall in spots, air is admitted trans.

versely of the incoming streams from the this being to thoroughly mix-the fuel and air and to-exert a change in the course of the fuel to Athe extent that it impinges upon the ent-ire surface of the incandescent target wall. f

The pipes 14`are preferably arrangedalternately of the vertical burners, so that air 'isadmittedbetween and at the sides of the streams, the general effect being to How transversely pastl the incoming vertical nozzle pipe, which may inject air under4 `burnt out refractory material 4forming the process of combustionis assisted by the airfrom the particles are stripped therefrom burners through the pipes 14, the effect of igienica iing melted,`-burnt out and otherwise affected so that renewal becomes' necessary. Here- 75 tofore renewal or repair of such parts necessitated the putting out Vof operation and complete cooling of the furnace. Accord# ing to the present invention,`we propose to permit the renewal of the target wall surface during operation of the furnace. To thisend, the target wall is disposedlaterally adjacent 4the front wall of the mixing oven or other point at which accessibility may be possible, and byopening the door, 17 bricks maybe inserted and placed upon the target wall by a suitable tool, or the same may be thrown therein, thereby providing a newsurface. ISlag and the melted and target wall, iiow into the base 20 and may be Vremoved through thel door 21.. By enabling thisrenewal of the target wall surface at vfrequent intervals, the furnace may be maintained at-its maximum efficiency at all times, without necessitating any loss of time or heating effect.'

In addition to the general. effect 'above noted, it should also be observed that the air entering.through'pipes 14 is relatively cold as compared to the fuel and flame stream and since such air is induced its velocity is lower. thanl that ofthe incoming fuel.' -Two 'res'ults flow therefrom. First the incoming Y fuel is, as it' were', projected through or 105 -caused to flow past a slower moving body of air, and therefore, each burning vparticleofl -solid is insured of being brought into contact with fresh air, i. e.,.air containing oxygen, as

it traverses the combustion space, which means not' only that oxygen for combustion is always athand, as combustion proceeds, but also thata sort o f scouring action takes place byY virtue of which the gases v,emanating and the surface of the particles kept exposed to air. The other result is that while eddying is set up at the outer surfaces of the fuel and flame stream, complete admixture of the fuel and air doesnot occur at once. This follows fromthe fact-that a relatively cold streamjof air, 4because of its temperature, follows astreamline course or path, well defined and definite until its temperature is considerably raisedA when complete commingling occurs. The downcoming fuel stream ofV higher velocity determines the y path of the incoming air to a large ,extent, by virtue Yof'its forceeffects, and this with the feature above noted, causes the in- A 464,849, lled April coming air to follow the general stream line course of the fuel and flame stream, with some air at the lower region thereof, until the temperature is suiliciently raised for complete commingling. Thus a body of air into which heavier particles of the fuel will find oxygen in gravitating, is insured. Furthermore, the admission of air through the pipes 14 protects the front wall and makes it possible to shift the admission means or burner near such wall which in turn makes possible the U-shaped course of the fuel and iiame stream in the chamber.

We have illustrated. and described preferred and satisfactory embodiments of our invention, but it is thereof, as defined in the appended claims.

No vclaim is made herein to the process disclosed, the Same being made the subjectv matter of a divisional application, Serial No.

We claim:

posed to the outlet iow, means for introducing the pulverized coal 1n particles flow past a slower moving bordering body of air.

2. In apparatusl for burning. pulverized of said chamber in a downward direction ad jacent the front wall of the chamber and at a velocity greater than the .outlet flow, th

whereby the entering fuel particles flow past a slowerimoving bordering body of air. 3. In apparatus for burning pulverized coal, the combination of a furnace' chamber having an outlet in an upper part and draft creating VVmeans, heat absorbing surfaces exposed to the outlet fiow, means for introducingr the chamber and at a velocity obvious thatchanges Inay be made therein within the spirit and scopeffrhaving an an upper ward 'direction adjacent the front wall of greater than the outlet `flow, the coal admission means being located to one side of the outlet so that the fuel and flame stream describes a U- ,coursc through thegchamber to the o utlet under the action of the draft, said chamber under theaction of the draft, said chamber means through .which posed to the-.outlet flow, means for introducing pulverized coal and air in an upper part of said chamber in a downward diflame stream whereby the particles of fuel flow past a slower moving body of air and heatabsorbing surfaces eX- y theirs" part of said chamber in a downwhereby also air is provided on the'conveX i side of the fuel and 'flame stream into which heavier particles of fuel gravitate and find' their oxygen.

6. In apparatus for burning pulverized coal, the combination of a furnace chamber.

having an outlet in an upper part and draft creating means, heat absorbing surfaces eX-v posed tothe outer Howa and means for in- I direction adjacent the front wall o-f the` troducing pulvdlrized-coa-l and air. in an upper part of the said chamber in a. downward chamber and at avelocity greater than the outlet flow, such means being located-to one side -of the loutlet so that the fuel and flame stream describes a Ufshaped course through the chamber to the outlet under the action of the draft, together with .means for ad mitting a trough-shaped body of air ad jacent to the incoming fuel, the base of .said4 trough-shaped body being on the convex side of the fuel and flame stream.

7. In a furnace of the class described, a fire brick structure providing van essentially vert-ical combustion chamber having an outlet in the upper part thereof, and an extenc sion to a side of said outlet, means creating a draft, burner means to one side of the outlet introducing pulyerized vcoal and a por tion of' the air required for combustion downwardly at the upper part of said eX- tension Whereby'the fuel and flame 'stream stream, saidv burner mea-ns introducing therif `fuel -at a velocity higher than that of the air admitted through said battery of inlets.

In testimony that we claim' the foregoing as our invention, we have signed our names in presence -of two subscribing witnesses.

JOHN E. MUHLFELD. Vvinci-Nuis. z. cARAcRisTI.

Witnesses: Y K C'. G. MILLER,

J; C. CHAPPLm

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