US1707474A - Oil burner - Google Patents

Description

April 2, 1929. I:- A, HEATH 1,707,474

OIL BUNER Filed Aug. 5, 1925 4 SheetsK-Sheet E 'MII A zu lllllll April 2, 1929. F; HEATH `1,707,474

' oIL BURNER Filed Aug. 5, 1925l -4 sheets-sheet `4 K fr/'wf Affeazh Patented Apr.. 2, 1929.

UNiTao. srarlaisg PATENT `l.o1-Fica FORREST HEATH,`OF DETROIT, MICHIGAN, ASSIGNOR F ONE-THIRD T0 HIMSELI, ONE-THIRD T0 KARL 1B. SEGALL, AND ONE-THIRD T0 WALTER F. TANT, .ALL 0F DETROIT, MICHIGAN.

OIL BURNER.

`Appiiaitmii ineav August s, 1925. serial no. 47,709.

My present invention is shown in connection with an oil burner of the so-called automatic type adapted to burn liquid fuel, particularly the heavier' or so-called fuel oils,

5 and the construction .of the burner unit peculiarly adapts it -for converting ordinary coa-l burning furnaces into oil burners but it will be evident that various features of the invention may be applied to other burnlo ers adapted for other uses.A

The apparatus includes meansfor initially forming a crude, over rich carbureted mixture of oil spray-suspended in and projected with a relatively small percentage of primary air, in combination with special homogenizing and propelling means whereby the spray in this initial draft is atomized and intimately mixed with said initial air and also with some additional primary air and the whole projected asa homogeneous fuel draft in close relation to the main draft of tom and its inner surface cut off from the' air necessary for complete combustion. 'Ifhis fuel draft may be caused to burn according to my lnewly discovered method described below; but various features of the homogeq nizing and propelling means may be used in connection with fuel mixtures of primary air with vapors or even gases derived from other sources or where the combustion is not caused to develop according to the preferred form of carrying out the invention.

The/means for forming the initial spray and air draft is shown as being of the centrifugal spra cup type. A. small electric motor is emp o ed to rotate thecup at the speeds require for centrifugal operation and preferably this same motor is utilized. fordriving my homogenizing-and propellin means.,

n the preferred embodiment, the draft vmixture is propelled outward, in. a circular sheet, above a hearth that closes the greater part of the bottom of a furnace so that chimney suction or equivalent draft-inducin difference'of pressure is caused to take e fect through the air inlets controlling the main supply of air for supporting complete' combustion, preferably this'main air'draft is through an annular inlet closely surrounding theatomizer outlet and preferably the main air draft is directed upward to inter-v sect the path of the initial air vand spray mixture.

An important feature of the invention is the attainment of practically perfect combustion without the use of excess air, yet

With ractically noiseless operation and freedom rom roaring which has heretofore been an unavoidable accompaniment of eicient' combustion of sprayed or atomized fuel oil. According to the preferred method, the combustible mixture is projected outward from va central rotor with such force and under such conditions that the mixture will be ignited and the flame will begin around a circumference as remote as may be desired from the rotor, with the result that the flame l line may be'localized adjacent the edge of the hearth where it oins the wall of the furnace or boiler', so that the flameline will be the lower edge of a continuous'wall or cylinder` of flame conforming to and, as it were, clinging to the inner surfacesof the walls to be heated.

This cylinder of flame is closed at the botupper face of this layer does not ignite because its air content is too small and too uniformly distributed. Hence instead of burning 4it becomes preheated ready for 'the energetic combustion that follows impingement on the surrounding' walls.I Furthermore, the upper surface of this sheet entrains from above some oftheburned out air which is deficient in free oxygen and rich in carbon dioxide while the lower surface entrains fresh air. posite'sheet impinges on the encircling walls, the impact and commingling of constituents results in a flame which is slow-burning and of non-explosive quality particularly onthe inner or exposed surface, whereas the` surface contacting with the boiler or furnace wall is much better supplied with oxygen. Consequently, the exposed surface has no roaring tendency while the maximum heat When this comdevelopment is close to the wall to 'be heated.

4The circular wall of flame which I produce in this way, though remarkably uni- `form, is likely under varying conditions of tate around the axisof the burner alongthe rotor thatdischarges a relatively powerful :blast alon' -lines more or less tangential to a circle w ich is of substantial diameter as Acompared with Ithe diameter of the furnace or boiler.' The non-radial impingement of such a draft on the outer walls results in the above described slow rotary movement of dll the flame.

'llhe :most important factor in obtaining .the above effects is the combination with the primary air and spray projecting means, of a secondary or homogenizing propeller' or fan located'in-the path of the rich mixture from said 'rimary means. This propeller is referab y designed and. operated soas to de ect, bao and homogenize the primary air and oil mixture together iwith a substantial ladiniiiture of additional primary air,

while ensuring the desired high radial veloc? ity of the draft as a whole. By using fan blades having a forwardly wedging coin.n ponent, as in repellers, the blades may be arranged so tat they intercept and break' up all outwardly projected spray drops in the primary mixture, while at the saine time rgreatly accelerating the draft as a whole.

he thorough homogenizing thus accomplished makes it possible to mix in additional primary air to a percentage much nearer that necessary for perfect.combustion than has been heretofore practically attainable. That is to say, in prior motor driven oil sprayers where the' repulsion is mainly hy centrifugal. force, t `e primary carbureted mixture may be as a whole very deficient-in air yet certain regions or spots contain mii:- tures where the air and oil are in approximately explosive condition so that ignition occurs at such' points and 'thecoinbustioii line creeps in quite close to the burner, while relatively large drops of oil are thrown against the walls of the furnace or drop on the hearthunder conditions entirely unsuitable for perfect, efficient combustion; f

. The interference and yliomogenizing function of iny supplemental fanlisclearlyohs tinguishable -from its high velocity propelling function although these two functions are best served each in combination'with the other. j

- The lioinogenizerv referablyincludes two separate sets of bla es operating in succession on the spray'.` Preferabl theyare concentric, -the inner set encirc in projector and, in turn encircled y the outer set. The thus present successively higher periphera speeds to the outwardly travelingy 'sprayed mixture. Thesekblades are carried rby an annular. rim that projects horizontally the spray v trovare into the path of upward draft from the an-` nular'air inlet, deliecting and-baling said draft where it intersects the path of the spray, thoroughly mixing part of it with the spray and, under most conditions; deliecting part ofit outwardly'so that the lower face of the outwardly traveling draft adjacent .oil particles and homogenizing'thei'r mixture with the air. Hence they are designed for `substantial interference and baiing of the spray and draft.

While the blades will be of substantial ad? vantage if set radially, as in paddle wheels, l prefer to have them inclined to' the direction of peripheral 'movement and also incline'd to the plane of rotationso that they have an inclinedfplane or wedge propelling effect as in a screw propeller as well as the.,

centrifugal blower or..ypaddle,.,wheel effect. Preferably', the wedge propellinv effect is upward and as the inner set ,oie blades is closed at the top bythe above described rim or wall at right angles to the axis, the draftinoveinent in this direction is baed .producing compression, deflection and eddy effects that contribute yto the atomizingy and homogenizing of the mixture. rllie outlet lades freely propels f the draft outward side of the outer set org blades is not closed in a circular sheet having its lower Surface overlying' and merging into the purer air' which has been deflected along the upper surface of the hearth.

l ani able to secure the .above homogenizing and propellingeffects with Va rotor say seven or eight inches in diameter driven at relatively low speed, say i700 or 1800 revolutions per minute. rllhese speeds are economical and are not destructive on the motor. @there have employed motor speeds twice as great without attaining or even discovering'` the possibility of. the above described features of oil burning according to my invention.

Furthermore, when the device is installed and-'operating as above described, whereby the non-burning sheet extends entirely to the walls of the furnace or boiler so that the upper face of'the non-burning sheet and the inner face of .the tlamecylinder are lentirely outY olf from freea ir,the diluent action of the products of combustion which ,filll the interior of the furnace is so great that ltemperaturesfon the top of the'burner within Ythe furnace are'in many cases 400 and500 uless'than in the .case off any rior l burners of this t e. `Furtherinoi'e,te temperatures lbelow t e hearth in `the a'sltpit where the;

ico

` sheet extends upward to the crown sheet and into the flues where the final phases ofcomplete combustion are evidenced by t-he blue flame characteristic of hydrogen and carbon-monoxide combination.

It 1s to be understood, however, that the blast of draft mixture which I am able to produce by means of my homogenizer includes vapor in suspension and is more like a gas than a mixture, and it may be controlled to burn in various Ways. For instance, by cutting'down the stack draft and thereby reducing the air supply, the highly colored llame may be made to entirely disappear, in which case the Whole body of the furnace Will appear to be filled With a slightly bluish or almost invisible flame, indicating that my homogenized mixture has some of the qualities and may be used to produce effects similar to those attainable by manipulating the air supply of ordinary illuminating gas, and I attain these results with ordinary fuel oil.

The above and other features and noveldetails of my invention will be more fully understood from the following description in connection with the accompanying drawings, in which Fig. 1 is a viewof one form of my burner and one form of installation and use thereof,

the burner and arts of the furnace inwh ich it is installed being shown in perspective Aand parts of the furnace'being broken away;

Fig. 2 is a vertical axial section through the burner and a portion of the hearth;

Fig. 3 is a vertical section on the line 3-3,

Fig. 4, showing a form of homogeni'zing.

mixer and propeller which is preferred for use in place of those shown in Figs. 1 and 2;

Fig. 4 is a plan View from below, Figd;

Fig. 5 is a vertical section like that of Fig. 2 but showing modified details of construction Fig. 6 is a sectional detail on the line G-G, Fig. 5; and

Fig. 7 is a. sectional detail on the line 7-7, Fig. 2;

In Fig. l, I have shown a complete installation in accordance with my present invention, because as is evident from the for"- going explanation of the preferred operamember having an' upst-andmg defining a drainage groove 17 and affordtion, there is a .true combination between the oil atomizer and projector ano the furnace in which it is installed, the latter being, ineffect the burner and the former being not really a burner but rather a carburetor for supplying the periphery of the hearth with a peculiarly uniform, stratified, combustible. As shown, the furnace is of conventional type, comprising an 'ash pitA, boiler walls B, combustion dome C, tlues l), l), communicating with the chimney, not shown, through pipe E, which may be controlled by the butterfly damper F and air inlet Gr., Such a furnace may be of conventional type, originally designed for coal burning,l but for my purposes the gratehas been removed And `the combustion chamber H closed in at the bottom by hearth I of refractory material at the center of which is the annular air inlet surrounding the rotary sp lay cup carburetor K. x

The air draft is through collar 10, through which projects'shaft 11 carrying homogenizing rotor12 having propeller blades 13v surrounding the outlet from the centrifugal spray-cup 30,' which is alsoimounted on said shaft. i f

As shown more clearly in Figs. 2 and 5, there is an annular passage' between the spray cup and collar 10, not only for clearance to permit rotation of the former,

.'butalso to provide for thelmain air draft' that is drawn into the furnace by chimney suction. i

The collar 10 is supported by a latform ange 16 ing asupport for the circular plate 18 on which `rest theinner ends of the hearth blocks. Near the edge of the hearth, and

referably outwardly directed, is a gas pilot light burner a', which is kept continuously 'l burning by gas supplied from any suitable source. The weight of the hearth support 15, 16 is carried by leg sections 19 telescoped in leg sections 20 and' adjustably held by screws 2l. There are preferably three legs to afford three-point support. v

As shown more clearly in Fig. 2, each leg sec-tion 20 has screw-threaded into the lower end thereof, anadjustableextension 22 secured by lock nut 23, whereby the legs may be readily adjusted to true vertical even though the floor of the ash pit be very uneven. The lower. end of each member 22 is ieo preferably headed as at 22. and the head is cushioned by a rubber block 24., held bv metal clip25 secured by central screw 26. Three-point support makes the adjusting operation easy.

Projecting through and concentric with the collar 10 is the :entrifugal or carbureting spray-cup 30, formed at the bottom with inlets 3l. fol-the primary air and carrying the'picker .tubes 3 2 for supplying the oil to viously the -cover member 39 may be .con-

sidcrcd as part of the cup 30. ln the form shown in Fig. 2 there is a second cover member fitted on top of 39. Preferably these covers 39 and 40 carry the baille annulus and the propeller blades described below. l` Disc 37 and cover plates 39 and 40 are clamped down on the top of the tubular cup memberl 34 by an annular clamping collar'41 secured by a clamping nut 42. All of the parts may* be suiiciently held against rotation on the shaft 35'by the clamping action of nut 42, but I prefer to provide a keyv44 engaging clamping collar 41 and extending. through v40, 39 and /37 into 34, as shown.

The bottom of the cup 30 is 'thickened downwardly to provide an adequate lateral bearing for the picker 'tubes thatextend.

downwardly therethrough and are Secured therein in any desired position of ,verticall adjustment by means -of screws 46. Also.

integral with the bottom ofthe cup Iand outside of the downwardly extending icker ltubes is a circular depending lip .47 a apted to close the opening into a suitable oil well casing 48. This casing is preferably provided with a plurality of horizontal diaphragms, as 49 and 50, which clear the rotary'closure 47 and' with itv form a labyrinth facilitating downward drainage of oil intov the oil supply chamber orwell 51- and baf- {lingeseape of oil'from said chamber to the outside. The depending annulus '52 serves similarly to baiile' splash and damps wave motion that maybe set u bythe pickers when rapidly rotated tolli t the oil. Rotation 'of the oil is damped by radial ribs 54 projecting from the bottom of the oil reservoir almost to the level of the normal surface of the'oil.

The oil well has a cylindrical barrel 55 and the cup bearingshaft 11, 35 hasta dow-n ward extension which is journaled on ball bearings in said barrel. For lubricating 4 purposes the top and bottom of the barrel below the lower` ball bearing and above the upper ball bearing are closed by packing held in bushing 58 'screw-threaded therein, the lower one being secured by lock nut 59.

The cavity is initially filled in with bearing grease and additional grease may be forced in at any time through duct 6()-qt by removing screw plug 61 and applying a grease gunu Below the shaftv and in alignment theremore@ with is the electric motor 63, which may be of ordinary construction adapted to use alternating or direct current, and designed to rotate the spray cup, pickers and homogenizing propellers carried thereby at the required speed which, as explained above, may

be as lowI as 1700 to 1800 revolutions per minute for a model, built on a scale which will make the extreme over-all diameter of the homogenizer eight (8) inches.

The armature shaft of motor 63 is detachably secured to the spray cup shaft by a flexible coupling conventionally indicated as comprising two similar members 75, 75, each having driving lugs 76, engaging a block 77 through'which the driving thrust is applied.

The oil well structure and motor are supported in any suitable way. As shown in Fig. 2, the oil well has three-point support fromthe platform member 15 by means ofl stud bolts 80 screw-threaded into 15 and passing through vertically k,apertured ears 81 which are integral withv and outside of a drainage gutter 83 which is integral withl "theoil well.4 Any desired positionof verti cal adjustment for. the oil welldrive shaft Aand spray cup carriedtherebymay be xed by loclrn1`1t84, vertical displacement being prevented by thumb nut .85.` In the form lshown, 'the motor issecured by screws 90 adjustably engaging adepending bracket 91 which is secured to the bottomv of the oil well -casing by ange 92 fitting against the same and secured thereto by screws not shown.

by deep iianges'93, and 94.

Oil is supplied through the bottom of the oil well by pipe 95 and waste oil from collecting gutter 83 is drained offthrough pipe 96 J The vertical bracket'member -91 is stayed lIhe gutter 83 is in position to collect oil i from the spray cup and also from the groove 17, which discharges through the duct '17,,

but its main .purpose is to lcollect oil that drains from the inclined hearth when the pilotl light fails --or for any other reason vwhen oil is being discharged at a rate greatly in excess of the rate at which it is being burned. In such cases the oil drains down the incline of .the hearth and through the' slots 10t1 in collar 10 and drips into the col-` lecting gutter 83, whence it goes through ipe 96 to a suitable control mechanism orming no pa'rt of my present invention.

i'It issuiicient to say that this mechanismaccurately controls the level of the oil in the oil well and completely shutsof the supply of oil whenever there is excess drainage through pipe 96.

The icker tubes are' preferably' of the shape siown in Fig. 7, the picker at -the lower end consisting of a narrow integral extension 322L formed by cutting away the tube, bending it horizontally through something less than a quadrant of a circle andV I- cutting the end to V-shape, as at 321 so that it acts 4asa plow to throw aside the oil that is not skimmed oli by the upper surface of the picker. The thin film of oilis skimmed o by reason of the fact that the oil is stationary while the picker tip is traveling circularly at high linear speed around a circle which may be, say, six or'eight inches in circumference, driven by a motor which is rotating, say, 1750'revolutions per minute.

Although the oil is mobile, it is held by.

. inertia against the thrust of the picker' and is deflected upward through the tube at high velocity. .Air is also carried up in the same way and the upward movement of both of them is facilitated by the fact that thetube is cut olf at an angle on the rear side as shown at 32C. The elect is-that since the speed of rotation of the? upper end of the tube is greater than that ofthe air within the spray cup, there is 'asuction effect applied at the outlet.' In this connection, it is to be remembered that an even greater suction effect is applied'by reason of the fact that the cup itself is a centrifugal blower and tends to draw in air through tube 32 as well-as through the regular air inlet 31. Ob-

viously also the picker is itself an air scoopv as well as an oil scoop.

The amount of oil supply can be gauged withl greatest\\accuracy by 'adjusting the vdepth ofoil in the oil well, and one advantage in havin therpicker cut away to a mere finger as s own; in lthe drawings, is thatthe amount of oil lifted will be 4more nearly-proportional to the depth of the oil.

The amount of oil could lalso be v.varied by vertically'V adjusting the picker tubes, but this isan undesirable way, since the oil level in the well should be kept 'as near-the top of the ribs '54 asl is'practicable, thereby mak ing the ribs as efective' as possible 1n pre- `venting'A the pickers from imparting rotary desirmotion tothe' oil, it being obviousl the oil able to minimize all disturbances o and hold it stationary as against the-scoop action of the pickers.

The spray thrown from theupp'er end of the picker tube is .subjected to centrifugal,

force tending to drive it'throu h the air `currents within the-cup 30 and 1n practice a much of its impinges on the side of the cup L adjacent the outlet annulus. Much of it,

however, goes into suspension .in the primary' air, which is dischargedl through the same outlet by centrifugal force which is assisted by the fan blades 38, although the latter may be omitted if desired. The richly carbuthe cover member39, and the adjacent bases l reted mixture is discharged upwardly agalnst the horizontal bale annulus 100 of ofthe inner propeller blades`13. The unsuspended oil creeps up the 'walls of the cup'l by centrifugal force and-fis projected. in

" have greater peri minute drops against the intermediate ortions of seid blades. `This is on a leve below the primarily carbureted air and in the path of the main air draft coming up through thecollar 10 at an angle to the horizontally projected liquid. This tends todrive upward the minute 4drops that have been shattered by impact with the inner faces of the blades 13, toward the baille 4plate 100 and those that have been caught by the outer surface of blades 13 upward toward the horizontal or baille annulusl 101 of the outer propeller. As la result of the baflling, eddying, mixing and shattering thus produced, a desired amount' of additional primary air becomes incorporated in homogenized mixture with a finely atomized liquid which is propelled outward. A large part of the upward maindraft, however, 1s

deflected art being driven outward by the' propeller lades as'an air 'stratum merging such high outward velocity that if any particles of oil remain too heavy for suspension in the carbureted mixture they will nevertheless be carried alone toward' the peripheryof the hearth or, ifJ any of them fall onA the' hearth, -as when the furnace is beitl started up, they will be speedily evapora and swept to the'periphery of the hearth.

the up` The homogenizing propeller may be made in a variety of ways provided 4the blades be formed with a view to propelling aswell as bathing and homogeniz'ing the draft. In-

Fig. 1, the blades are formed by radially and then bending these blades downward so slitting a circular disc to form narrow blades that they will surround and extend belowy l the lip of the lcentrifugal carburetercup and also twisting them so that they willl have the outward .wedging orpro elling effect in addition to the centrifuga effect.

and the bailiing effect. Even as shown in Fig.' 1, the lblade substantially encompasses the outlet of thecup so that when in rapid rotation, any drops from the -lip of the cup are interce ted and shattered. Even iao so, 'it mav be advisable to use an inner homoge I enizer of similar construction but of less radius `and preferably .with blades *of greater pitch than the outer blades.- A s before' pointed out .the inner set of blades heral. speed than the lip of the cup and t e outer set of blades .has

:so a sufficient distanceto A permit passa e of all greater peripheral speed than the inner set.

A rugged 4construction for the above purpose in which the blades are combined with extensive baflie surfaces at angles between 45 and 90 to thepath of outwardly projected drops, 4is shown in Figs. 3 Vand 4.

Here the cover discs 39b and 40a have the horizontal bafllin'g surfaces 100EL and 101a lset 4of blades has -a marginal rim v113",

which `increases the structural strength. of the anchorage for blades `1,13b and also serves as a guard to lessen danger from Contact with the periphery'. of the device While it is rotating at'high speed.

In F1g. 2 the homogenizing propellors are shown as being scantily supplied with propeller blades. Good results may be obtained by having the spaces between the blades in each set approximately equal to the widths of the adjacent blades, particularly if the registry'is such that a blade 13'rt coincides with each space between vblades l13, but in general it will be found that the close setting shown in Fig. 1 and even the non-propelling baille surfaces 113d in Figs.`3 and 4, will produce better results. In all cases, however, much depends upon the proportions,

designs and pitch, angles of the blades as well as on theirI dist-ance apart and relations to each other.

A. somewhat different arrangement of homogenizing propeller isshcwn in Fig. 5. Here the outer propeller Vcarried by the motorv shaft and rotating at the same speed.- as the ,cup may be the'same 'as that shown in any of the figures above. described, but

in lieu of the inner ropellorl -IJnay arrange a stationar set of lades 213, mounted on an upwar ly extending sleeve 248 spaced apart from the outer Wall of the cup 230 or a large .part offthe main ,air supp y.y 4.The stationary blades 213.l1atf the upper.. Y'edge thereof are inclined loutward-ly and are also twisted about their longitudinal axes 'so that they furnish inclined surfaces deflecting the spray from the c u'p outlet annulus upwardly and circumferentially forward in the direc-- -tion of rotation of the cup. This causes deec- L tion of the draft mixture and also the main airisupply toward the rear faces of the rotating blades 13, but the stationary blades may be more nearly radial andrmay even be inclined in the o posite direction so as to tend t0 baillev the raft in a direction contrary to the direction of rotation of the blades 13. In the preferred arrangement, the.

blades 213 tend strongly to deflect the drops from the draft upward toward the baille surface 101.

As the stationary blades have no rotary` mot-ion tendingto throw ofi' the oil by centrifugal force, I may provide the outside of the cup with helical propeller blades 228 designed to powerfully accelerate the main air draft in its upward movement so that it will be effective in its tendency to strip the oil upward off of the upper ends of the blades 213. A

The enclosing of the main air draft by the cylindrical wall 248 makes it possible to closely control the amount of air in this draft by means of a rotary damper 250 (see Fig. 6) controlled by an operating handle 350 projecting outward beyond the leg supports of the device.

his figure also differs from the others in that the Aspray cup 230 is flared outward more nearly in parallelism with the natural trajectory of `the spray and ainthrown from the outlet ends of the tubes 32, Ithus allowing more o-f the oil to be carried through the outlet annulus without impingemen't on the Walls of the cup. Moreover, such drops as do impinge on the walls will be cleared therefrom more rapidly by reason of the more favorable angle of impingement and also because of the much greater effect of centrifugal force duel to lthe wide angle of the mouth of the cup. In this Fig. 5 the motor and other rotating parts are carried by 'adjustablestud bolts 80, very much as in Fig. 2, but the drip trough 285 is on a lower level and more accessible. It is in position not only to receive drip from the hearth, but also fromY an opening at 290 in the side ofthe oil well. This opening is well above any level the .pickers are intended to work at and 'will only `come into operation in case the oil well' is flooded.

A further feature is having the baffles for reventing rotation of the oil not only along the bottom of the oil'well as at 254, but also around the sides of the well as at 354.

As explainedl above, my 4invention is not limited to the details of construction above described, nor is it limitedto the preferred method of use. Any of the homogenizer constructions shown in the other figures may be used in combination with the carbureting cup and air supply means shown in Fig. 5,

and with any of the forms it ispossible to adjust the amount of air and oil and` the proportions of air and oil and the outward velocit-ies with which theyfare propelled, so that the homogenized fuel sheet or layer will be non-burning until it reaches th'e periphery of the hearthy and will there burn in a wall lof flame clinginglto the walls of the furnace and extending into the flues. This .CFI

flame lmay be varied from a comparatively thin layer of dense yellow flame until the inner surface' becomes more indefnite'and more blue and the blue can be made to shade out towards the center until the entire fur- .nace cavity is filled with a bluish almost invisible flame in lieu of the highly colored y definite flame. l

As will be understood from the foregoing, a very important feature of my invention is having the central centrifugal spray cup spraying the fuel oil in a narrow zone about the periphery of the hearth, at the base of the upright Walls tol be heated thereby, in

rectly coupled -to the spraycup, althoughV such mannen that the flame line is localized 1n said zone along said base and is prevented from creeping inward toward the central spray cup. lThe various contributing factors are in the aggregate so effective, that an or.-

di-nary commercial type motor turning 17 OO.

to. 1800 vrevolutions per minute can be disimilar results may be achieved by the superspeed specially built motors'now-commonly used for such purposes.

An important factor tending to ensure this' locatlon of the flame line is thehomogenizing,

* and projecting with the spray of a relatively large volume of primary air propelled outward with and at approximately the same Ivelocity as the spray, thus serving the double a better fuel draft p ur o se of producing f whi e at the same time adding greatly to the volume, weight and ycarrying powervthat is practically effective in'carry-mg the fuel.

the hearth, at the base ofthe upright. walls,

instead of near the'sprayvv cup. The initial-l combustion zone is 'thus remote from the intermediate surfaces of the hearth between the cup and the peripheral walls. Thus their lnitially cold lsurfaces remain cold until the entire combustion process above described is in fullo eration, and thereafter they are protected rom being heated to combustion promoting temperature by theheat absorbvIng action of the unignited spray and air Continuously projected from the center out-y lward above said hearth surfaces.

I' have found in certain cases, however',

that if for any reason the flame line 'does break back to lt-he homogenizer, it will con- Y tinue there until the apparatus is stopped und restartedagain. Hence in stopping and l, restarting, it is highly im ortant tohave A,the motor reach full spee before turning vto promote l cracking of theheav creasing the speed of the motor.

rWhile there are various ways' of ensuring ignition at a oi'nt remote' from thefyspray cup, I prefert e arrangement shown Iin Fig. 2, where the pilot light is shown as'projecton` the oiland to turn off' the oil before ing its jet outward but at 'an angle lnclined towards theobserve'r, which, as will be noted, is substantially parallel. with the direction of spray and draft tangentially pro- 'ected from the s ray cup and homogenizer referabl ,this ]et is directed against the --surface o a cast iron member w', which is lkept hot by the continuously lighted pilot light impingingthereon atv all times, regardless of whether the burner is or is not operrating. Homogenized gases sweeping lengthwise along the flame of this pilot light may be ignited, particularly between it and the surfaces of thereby augmenting the effectof 'the that may fa l upon said surface and promotpilot flame in igniting Aoil spray ing circumferential progress of combustion around the periphery of the hearth.

'The cast iron surface itself when hot tends hydrocarbons to produce combustible met ane and `oxidation of carbon to produce carbon monoxide, but, if desired, the cast iron surface ma be covered with refractory materials, inc uding oxides or carbonates of well known catalytic metals.

curves into the upright surfaces of the furnace may be of similar refractory materials or may' be of ordinary fire clay.

The lagging` around the edge of the hearth where it- These refinements are not essential, howfever,.b ecause, when in full operation', mere lmplngement and deflection of my vcomposite draft causes very hlgh temperatures,

say 1800 F. or more, in the 'annular' zone of the corner between the periphery of the hearth and base of 4the furnace walls. Undoubtedly this intense heat evolution islargely the' result of incomplete combustion or exothermic .reaction yielding carbon monoxidey land lmethane fuel gases along with some superheated steam and-carbondioxide products of some complete'combustion that also occurs in-this zone. completecombustion is localized adjacent the hot furnace surfaces where the purer air Probablyv also the naturally' flowswhilev the oil cracking and fuel' -gas reactionsy are" mainly in the inpresented layers where there is only enoug oxygen for the exothermicreactions and wherediluent products of combustion entrained .from within the furnace serve to slowdown the ox1d1z1ng processes.

Whatever vmay be the*` .precise details of' working out vof thesereactions, the characteristic effect attained in full operati-on issudden very high temperature in this narrow zone at' the basev of the walls resulting in the production of sufficient fuel gas 'to complete the breaking down of all the fuel Constituents of the draft and with decreasing temperatures as the slow bright flame flows up the walls of the furnace, until at the upper part and`in the fiues there is only the dark or blue flame characteristic of complete combustion of fuel gas.` When the furnace has been brought to high temperature by this method, the air may be cut down until the combustion is nearly or entirely two-stage, i. e., exothermic reaction or partial oxidation producing fuel gases followed by slow complete combustion of said gases, evidenced by great decrease'or even complete disappearance of the bright llame sheet and diffusing of dark or blue flame combustion from the walls toward the center of the furnace. Intermediate conditions are easily produced -by simple changes o f the proportions and quantities lof oil and air. f

T he furnace, particularly the hearth, is an important factor, as will be evident from` `the fact that a burner cup provided with the homogenizer shown in Figs. 3 and 4, when operated in the open air without any hearth, will be found to'deflect, and downf wardly project the main body of the air draft at an angle of approximately Of course, no such thing happens in practice, because the hearth serves to support and guide the draft that sweeps its surface.

I claim:

l. Oil burning apparatus for use in a furnace having a combustion chamber with a stack gas outlet and a hearth with a cen-` tral. opening closingthe lower end of said chamber, said 'apparatus including a mixing and projecting device in the opening in the hearth spaced therefrom to provide l an annular inlet for a main draft of air ensaid hearth to a main draft o tering the combustion chamber, and comprising rotary means having a `rotor element to draw up oil and air therethrough,

within the main draft annulus, and mix the same to produce a rich mixture; and to pro-v ject 1t laterally between .the products of com-l bustion in the combustion chamber and the main air draft, said rotor element including a. deflector element above the path of said rich'inixture adapted to force the main. air draft outwardly above the hearth, said fuel. draft entraining products of combustion at its uppersurface and air at its lower surace. i

2'. Oil burning apparatus for use in a furnace having a combustion chamber with aA vstack gas outlet and a hearth with ,a central opening closing the lower end of said chamber, said apparatus including a mixing and projecting device arranged in the opening, and spaced from the inner edge .of provide an annular` inlet for air entering the combustion chamber, and comprising means, including a rotary element having outlet means at its periphery,

to draw up oil and air and mix the same to produce a rich mixture and to mixture through said outlet project th-e j the products of combustion 1n means between ,the combustion chamber and the main draft stack gas outlet and a hearth with a central opening closing the lower end of said chamber, said apparatus including a mixing and projecting device in the opening in the hearth spaced therefrom to provide an annular inlet for a main draft of air around the mixing and projecting device, and comprising a rotary element to draw up oil and air and mix the same to produce a rich mixture vand to project said mixture laterally between the tion in the combustion c amber and the main air draft, and to deflect the main air draft outwardly above the hearth soV that the fuel draft strikes the upper portion of the main air draft, thus entraining products of combustion at its upper surface and air at its lower surface.

4. In an oil burning apparatus, means for projecting a fuel draft of oil and air in combustible `relation to the air supply required-for complete combustion, including a centrifugal carbureting cup, means for rotating said cup at high speed to atomize and project oil and primary air in an annularly spreading layer constituting the fuel draft and means for directing the main air supply in an annulus surrounding said cup and in a direction for intersecting the path of the annular' layer constituting the fuel draft, an annular deflector carried by the carbureting cup above the fuel draft, and inner and outer sets of propeller blades carried by said deflector and radially surrounding the annular outlet4 thereof-to interroducts of combusi les cept, homogenize and propel the draft mixcombustible relation to the air supply required for complete combustion, including' a centrifugal carburetin cup, means for rotating said cup at hig speed to atomize and project oil and primary air in an annularly spreading layer lconstituting the fuel draft, means for directing'the main air vsup ly in an annulus surrounding said cup an in a direction for intersecting the pat tends to minglewith the annularly spreading fuel supply and all portions of the mainair supply are deflected towardI parallelism with said fuel draft.

6. In an oil burning apparatus, means for projecting a fuel draft of oilland air in combustible relation to the air draft required for complete combustion, including a centrifugal carbureting cup, means for rotating said cup at high speed toV atomize and project oil and primary air `in an annularly spreading layer constituting the fuel draft, means for directing the mainair draft in an -annulus surrounding said cup and inA a direction for intersecting the path of the annular layer constituting the fuel draft at an angle greater than forty-five degrees, an annular dellector carried by said cup arranged abo-ve the fuel draft or mixture of oil and primar air to deflect said main air draft where y-thc'inner portion of the main air draft tends to mingle with the annularly spreading fuel draft and all portions of the mam air draft are deflected toward parallelism with said fuel draft, said deflector being of much greater diameter than the fuel cup and having at its margin a downwardly directed flange lmember adapted to intercept the path of the centrifugally projected fuel draft from the carbureting cup and to baffle both thefuel draft and the portion of the main air draft impinging thereon.

7. In an oil burning apparatus, means for projecting a fuel draft of oil and air in -combustible relation to the air draft required for complete combustion, including a centrifugal carbureting cup, means for rotating said cup at high speed to atomize and project oil and primary air in an annularly Spreading layer constituting the fuel draft, means for directing the main air draft in an annulus surrounding said cup and in a direction for intersecting the path of the anynularfuel draft at an angle greater than forty-five degrees, an annular dcflector carried by said cup arranged above the fuel draft or mixture of oil and primary ai'r to deect said main air draft whereby the inner portion of the main air draft tends to mingle with the annularly spreading fuel draft and all portions of the main air draft. vare deflected toward parallelism with said4 fuel draft, said deflector being of much .greater diameter than; the fuelcup and having at its margin a downwardly 'directed flange member adapted `to intercept the path of the centrifugally projected fuel draft from the carbureting cup and to baille both the fuel draft and theA ortion of Ithe main I air draft impinging. t ereon and having openings through which the -deflected air and the baffled mixture may escape radially.

8. In an oil burning apparatus, means for projecting a fuel draft of oil and air in combustible ,relation to the air draft rcquiredv for complete combustion, including a centrifugal carbureting cu means for rotating said cu at high spee to atomize and project oil andl spreading layer constituting the fuel draft,

primary air in an annular-ly means for directing the main air draft in an annulusI surrounding said cup and in a direction for intersecting the path ef the annular fuel -draft at an angle greater than forty-five degrees, an annular deflector car,`

ried by said cup arranged above the fuel draft or mixture of oil and primary air to deflect said main air draft whereby the inner portion of the main air draft tends to mingle with the annularly'spreading fuel draft and all portions of the main air draft are deflected .toward parallelism with said fuel draft, said dellector being of much greater diameter than the fuel cup and having at its margin a downwardly directed flargc member adapted to intercept the path of the centrifugally projected fuel draft from the carbureting cup and to baffle both the fuel draft and the portion of the main air draft impinging thereon and having openings through` which the deflected air and the baffled mixture may escape radially, said margin being formed with propeller blades radially intercepting, baflling and ropelling outward the portion of the dra t mix'- ture impinging thereon. i

9. In an oil burning apparatus, means ,for projecting oil and air in combustible relation, including a centrifugal spray means and means for rotating said first means at high speed to project theoil in an annular spreadmg layer of spray, in combination with a set of propeller blades and means for supporting the same in fixed relation with.

the centrifugal spray means but located radiall youtside of such spray means and extendmg across the plane of said annular l layer ofspray.

10. In an oil burning apparatus means for radially projecting oil an air in comlmstible, relation, including a centrifugal sprayv intercept, homogenize and propel the draft mixture impinging thereon.

11. In an oil burning apparatus, means for projectingl oil and a1r in combustible reprojecting an annularlypspreading oil spra draf t,'` and audriving motor rotating said and means for directing an u ward dra t .,blades.

of air across the path of the projected spray, Signed at New York in the' conntyv 'of 10 a series of outwardly acting fan blades in an New York and State of New York this 31st i 5 yannulus spaced from and encircling said oil day of July, A. D. 1925.

A projecting means and extending across the path of the projected Aoil and intothe air f' -VFORREST A.

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