US2247855A - Oil burner - Google Patents

Description

July l, 1941.

l.. o. SELBY OIL BURNER 2 Sheets-Sheet l Filed Aug. 2, 1937 vNvENToR: i LYNN QSELBY L. O. SELBY OIL BURNER iFiled Aug. 2. 193'? 2 Sheets-Sheet 2 v VW ENTOR VMM JSSLBY ATTORNQK.

Patented July .1, 1941 on. BURNER Lynn Otis Selby, Rocky Hill, Conn., assignor to" The Sparmal Engineering Corporation, a corporation oi' Connecticut Application August z, 1937, serial No. 156,989

(ci. s-2s) w f Claims.

My invention relates to oil burners.

It has among its objects to provide an improved oil burner, and, more particularlysuch a burner of the so-called power type, i. e. of the typere quiring pressure to operate the same. A further object of my invention is to provide an improved power type burner having improved means for heating and vaporizing the oil and igniting the same and for supplying oil and' air thereto, whereby more complete combustion of an increased amount of oil is obtained in such manner as to produce an exceedingly hot yet entirely clean llame and whereby the burner is adapted to intermittent operation in accordance with variations in demands for heat. Still another object of my invention is to provide an improved burner including a plurality of burners and wherein one of the burners is a preheating burner and constantly maintains the vaporizing means of the other at an operating temperature, and the other is intermittently operable in accordance with variations in demands for heat affecting associated control mechanism. vA still further object of my invention is to provide an improved burner comprising an improved combination of a distillate burner with a power burner wherein the distillate burner can operate independently to contribute substantially to the heat output and wherein it also acts to vaporize and ignite the oil for the power burner in an improved manner maintaining the latter ready for operation at any time. Another object is to provide an improved construction wherein the two burners are coaxially arranged in an improved manner with the oil and air supplies for the power burner passing upward around the axis of the distillate burner in such manner that the burners may cooperate in the new and improved manner above described. A still further object of my invention is to provide an improved burner installation including the above described mechanism and having improved means for Supplying oil to the distillate and power burners and supplying air to the two burners while controlling the air and oil supplies to both burners in accordance with the demands of the installation, the power burner being responsive to changes in temperature or pressure. These and other objects and advantages of my improved construction will, however, hereinafter more fully appear.

In the accompanying drawings, I have shown for purposes ofY illustration, three embodiments which my invention may assume in practice.

In these drawingsy Figure 1 is a diagrammatic view of a heating installation equipped with one iormo! my improvement, a portion of the heater being broken away to show the burner in side elevation there- Fig. 2 is an enlarged view of the burner and its supply and control connections removed from the heater, the outer casing of the burner being broken away to showthe shells of thedistillate burner and the shells also being broken away to show the power burner disposed therein, while the casing containing the supply connections to both burners is also broken away to facilitate illustration;

- Fig. 3 is an enlarged plan vievLof the burner base shown in Figure 2, the shells being removed to facilitate illustration and the casing and power burner tubes being in section on line 3-3 of Fig. 2;

Fig. 4 is a similarly enlarged vertical sectional view through the burner base, the sections being taken on line I-I of Figure 3 and the shells also y being added;

Fig. 5 is an elevational view of a modiiied installation, herein a steam pressing installation quipped with my. improvement, and

of my improvement including oil and air connections for multiple burners, parts of only one of the distillate burners being shown, to facilitate illustration.

Referring to the construction shown in Figure 1, it' will be noted that I have therein shown a heater i of any suitable type for heating air, hot

water or steam, and having mounted in the nre' box A therein above a usual false bottom orbaiile la, a vertically delivering burner of my improved construction, generally indicated at B, this burn- ,er being of a type adapted to be automatically controlled through an electric control mechanism, such, for example, as a usual thermostat 2, lacting to control the supply of liquid fuel from a storage reservoir 3 and air from a blower 4 to thepower burner of the improved burner B, as hereinafter described. I

Referring more particularly to Figures 2, 3 and 4, it will be noted that the burner B' has an outer casing 5, herein having a usual bevelled removable top 6 and a lower axial upstanding neck 1.

Coaxially disposed with respect to this neck and 1 within the casing 5 is a distillate burner, generally indicated at 8, and adapted as usual in such burners to have vaporized fuel supplied f thereto andto develop high temperature," and herein comprising usual shells 9 and a base l0 having usual burner grooves I l supplied from a Fig..6 is a perspective view of a modiiied form carbon leg I2. While not limited thereto, herein, this distillate burner is of the so-calledBunsen 2,020,867, the same being found to be Well adapted to my purposes. However, it will be noted that herein the patented construction is modified and improved in certain respects to adapt it to be used in combination with myfimproved power burner. Herein, instead of having a central chamber, it will be noted that I provide an annular vapor distributing or so`called vaporizing chamber I3 to which the carbon leg ;I2 is herein connected at one side of the axis of the base I0 so that the vapor will notllargely;ilow1out but willibe ffor'ced .y 1

through this adjacent channel a to iiow'more evenly tothe next outer groove `I I.

`which, in turn, controls the supply of oil therefrom to a pipe line 24 which is connected to the bottom of the carbon leg I 2. The oil for the power burner chamber I9 is herein also supplied. from the reservoir 3 through the pipe line 20 and float'valve 22, but controlled by a separate needle valve 25 controlling the ow through a pipe line 26 which opens into vthe chamber I9, herein at a point near the bottom thereof. Thus it will be evident that while voilim'ay be supplied from a common reservoir to Yboth burners, thel same may befseparately rcontrolled by the different needle valves 23, 25 to vary the amount Thus, when usual covers Ilaare placed over` the.

radial channels I3b between suitably. connected l .the 'lower end olflthe pipe I6 surrounding the.

ible to,supply' oil l rerentburners whenever desired.

1k Operatively associated withthe tube I1 is improvedair supply means.V Hereinan elbow 21 is as by lthreading or brazing on connection between the pipes Ill and II, and this elbow is, in turn, connected with-ahorizontally disposed air supply pipe 28 which is herein connected to anysuitableblower,

Referring more particularly toy thisfpow'er: 'v

burner, it will benoted that an outer tubular member I6 extends up axiallythroughthis platel I l and the bottom of the burner base- I0 toa point substantially above the herein to a point above the shells gars illustraiz'efiisV ameter, herein, as preferably, terminating Yat substantially the top of the burner base. 'It lwill be noted that the tubes I6 and II are joined at within the outer tube I6 at the top or the tube I`I. Preferably, the lower end Isa of tube I6 is formed of brass or other good heat conducting material so as to abstract heat readily from the base I 0 of the distillate burner, and is screwed, welded or otherwise suitably fixed to the latter, all in such manner as further to facilitate heat transfer therefrom. The upper end I 6b of the tube I8, which is above the burner base and is telescoped over the upper end of portion I6a, suitable alloy steel example, a very high chrome steel. It will be evident that the chamber I9 which is inside the tube I 6 and surrounds the tube II provides, in effect, a vaporizing chamber or generator of large capacity.

The Supply of oil distillate burner 8 I'I afl-smaller di:Av

inner-impe' l1 herein an electric 'vapor inethe power burner vaporizing'chamber I9 and cause said vapor to' be vignited .by the 11am to produce this effect. Here attention is also directed to the fact that I also here provide an outer casing 3| connected to the lower end of the neck 'I and enclosing the air supply 28 of this construction and suitable adjustment of these supports 32, 33, it is made possible not only to control the vertical position of the burner base I0, butto level the same in intersecting planes.

dicated at 99, through conductors 3I, while conductors 98, connected in parallel to the conductors 31, lead to a suitable controlling valve 39 preferablyvof a usual. solenoid type adapted to control the flow through the pipe line 26 and i Cil valso preferably disposed-within the casing 3I.

As a result of this construction and due, lit .isf

believed, to the delay inherent in bringing the*` I motor 36 up to speed, the solenoid v"valve 39L is.y

flrst operated when current ilowsv simultaneously through the lines 31,' 38,111 such manner vas insure that oil will'be supplied-totlrieI power burner chamber I9 before the motori .96 reache its normal operating speed. L;

In the operation of my improved construction it will be understood thatrthejdistillate' br'ne l l is rs't started vina usualmanner ndjthat `this burner lcontinuesfto operate',. preferably',.at

constant flame determinedjbyQthejsetting needle valve 2l, throughoutfthe,l operationjo y th device, the damper, Ilja "t course fbeingf adjusted as needed. .When this burner has been'ioperatin the entry'of air into the vaporizng chamber while the vapor passes in the iforml of f unburned gaseous vapor into the combustionjchamber With the vaporizing: chamber I9 thus"jlieat'ed,'fit

will be evident. that vthe power burner will'. be

started 'automatically-f whenever oill is fsllpplied throughthe line 26 into thelchamber I9 and the blower 29 is started. VIn practice, thev distillate burner 9 brings the tube I8 to a suilciently high temperature that the power burner pennies'.thesbumer,hase we and the vpartici tubular-' member' Ifformingfjtheiouteruwallof ,the power burner vaporizingf cham-v fber I9, to va propertemperatur-e,v i; e. `to such` temperature as to yvaporlze 'oil in that chamber and cause vapor 'tovrise therefrom byf its own v` heat and in suchV vmanner asfto act to prevent vfrom 'afsingle'boilerwhile at the same time submay thus be started within ten to twenty min\ v ute's after starting the distillate burner. Attention here is further directed-to the' fact thatwith the pipe I 6 at high temperature, the oil` in the chamber I9 between this pipe and the air pipe I I is very completely vaporized as described above and is also sucked up along the outside of the pipe I I by the air stream and into the path of the air flowing from the blower through the pipe 29 and pipe II as heretofore described; the baffle ring 30 also assisting in obtaining an effective mixture of the air and gas and directing the flame` up through the combustion chamber. In practice, it is found that the flame burning at the upper end of the pipe l1, as heretofore described. and extending above the upper end of the pipe I6 may operate over long periods without any evidences of carbonization, whilel in that portion o1' the flamewhere such heat 75` is most useful, i. e. in the heater fire box, while the blue llame, being in the tube I6, is disposed in the most effective heat conducting relation for such a blue flame with respect to the vaporizing and combustion chambers. Obviously,

when the power burner hasv once been started, it'

will continue to operate under the control of the thermostat in a well known manner, the motor 36 forthe blower 29 being stopped and started in accordance with changes in temperature acting upon the thermostat; the heated base I0 and tube I6, due to the continuously operating distillate burner, acting to maintain the chamber I 9 at vaporizing temperature in such manner asto insure 'immediate starting of the power burner whenever oil and air 'are supplied thereto.

In this connection, attention is also directed to the fact that with the'tube I64 thus maintained at a high temperature by the distillate burner, the power4 burner canl` either start l or stop in accordance with temperature require? ments of thermostat 2 and with a minimum of smoking.v Y

lIn Figure 5 I. have illustrated a modified form of-installation. In this figure, I havev shown an improved'burner Aof the sameV general character as that heretofore described, used in connection with any. suitable steam boiler 40 of the vertical tube-"tipe'usual in connection with a steam presser,"the latter including a usual stationary pressingelement 4I and a movable cooperating pressingzelement 42 which is controlled by usual controllmechanism voperated by afoot lever 43'. With, steam-supplied from the boil I0 to heat the kcoop'eratir`-1g,lzpressing elements and'42 and the operation off thereto .pei

the. latter and the steam lsupplied. n fcontrolledby .the Vfoot klever 43 own manner,"it isvfound that my rovedu urn'erkv will supply suilcientsteam to ntlnuous Aoperation ofthe pressing maery ubstantially vreducing the cost ch machines, heretofore opas. In fact, with my'improved v urner ,connectedjto',such a boilerw, it is possi- 'bleto operatefalplurality of pressing machines stantially reducing the heating expense. Here obviously, ,asusual in boilers, a .pressure responsive control (not shown) will be used in 50' place of the temperature responsive mechanism heretofore described.

In Figure 6. I have illustrated a further modified construction wherein while utilizing my improved burners, a plurality of the same may be connected to a single-air supply line 44. Here it will be understood that the distillate burners, parts of only one of which are illustrated, are each of the same construction heretofore described in connection with Figures 2 to 4, so that a further description thereof is unnecessary. However, it will be noted that, as in a preferred construction, the connections between the air supply M and the several tubes I6, on which the burner bases are carried as heretofore, include connections V45,46 so constructed and arranged that the connections to the several tubes from v the common air supply are of equal length in such manner as to insure uniform operation of all the burners. Here oi' course, it will be understood that while only an air supply has been shown in this figure, oil and air supplies similar to those heretofore described in connection with Figures 2 to 4 and similarly controlled, are also provided, while the member 44 is also enclosed in an adjustably mounted casing similar to the `tion, as well as to the long casing 3|. It will also be understood that while only three such burners have been shown, I contemplate the use of two, four, or as many as may be desired, arranged in such a cluster as shown, or in alignment, while I further contemplate the use of one or more of these burners either in connection with a single boiler or in connection with a series of boilers.

As a result of my improved construction, it is made possible to obtain wholly new results as regards maximum temperature from a power burner, temperature tests indicating that the ame produced by my improved burner is substantially hotter than that obtained by any other power burner of which I am advised. This is believed to be due to an improved and more complete v'aporization and resultant more complete combustion, resulting from my improved construction. Attention is further directed to the fact that these results are obtained without requiring an intermittently operated supplementary burner, the distillate burner in my improved construction operating continuously and without necessity for manual throttling or other attention on the part of` the operator, than the starting operation and the setting of the needle valve and damper to insure continued operation at the desired rate of oil and air ilow. Further, it will be noted that these results are obtained without requiring any supply of oil under pressure to the power burner, the oil instead being supplied by gravity from the reservoir, and, moreover, being vaporized completely in the power burner chamber I! before it is ignited, as distinguished from as heretofore being sprayed into the air stream or otherwise picked up by the air stream and supplied in globules of cold oil directly into a combustion chamber. As compared with prior power burners having a stationary oil delivery, attention is also particularly directed to the fact that while obtaining the above advantages, I am also able to produce a power burner which is free from objectionable roar in operation, this being believed to be due to the use of my improved power burner structure and in part also to the use of an air supply which is of substantially the same diameter, and preferably a substantial diameter, from the blower to the outlet inside the pipe I6 and also to the provision of the ring 30. Here also it will be noted that due to the use of gravity and the constant level valve 22 in the oil supply to the distillate and power burners, it is made possible to produce an exceedingly safe construction wherein the oil levels may not exceed the limits set under the most strict municipal regulations, all danger of flooding thus being eiectually avoided even should the burner go out for any reason, as, for example, upon failure of the oil supply. Attention is further directed to the marked flexibility of the same in operation in accordance with temperature, or hot water or steam requirements, it being possible in my improved construction to vary the oil consumption by the power burner, as de- Sired, by adjusting the needle valve to any selected point between the limits thereof, without affecting the heating character of the power burner ilame or causing the latter to smoke and carbonize the burner and ilre box. Attention is also directed to the simplicity of the construcwearing qualities of the structure, all need for high pressure pumps andignition mechanism being eliminated and the only moving parts, apart from the relay, being the simple motor driven blower and the .when the -pipe Ii is made of a suitable alloy adapted to withstand the high heat, the mechau nism is adapted to function indenitely without attention other than ordinary service requirements in connection with the thermostatic control of the same. Attention is also particularly directed to the markedly reduced manufacturing cost and the reduced operating and maintenance expense of my improved mechanism. These and other advantages of my improved construction will, however, be .clearly apparent to those skilled in the art.

While I have herein specifically described three embodiments which my invention may assume in practice, it will be understood that these forms are shown for purposes of illustration, and that my invention may be moditled and embodied in various other forms without departing from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1. In combination, a burner having vaporizing means and oil supply means therefor, means for delivering air under pressure entraining the vapor as it emerges from said vaporizing means, a

combustion chamber for the combustible mixture above said vaporizing and delivering means and receiving air and vapor therefrom, mechanism for conditioning the burner-for starting including means for heating said vaporizing means to a vaporizingtemperature and for effecting ignition of the combustible mixture, and means controlling the supplies of air and oil for starting and stopping said burner.

2. A power burner having pressure air and oil passage means, and having a vaporizing chamber supplied from said oil passage means having an upwardly directed outlet, and means for maintaining said chamber sui'llciently heated tov vaporize oil in said chamber throughout the operation of the burner, and said burner also having a combustion chamber above and communicating with said vaporizing chamber, the air supply means delivering air adjacent the outlet of the vaporizing chamber and entraining the vapor as it emerges from said vaporizing chamber and said air supply means discharging sufilcient air into said combustion chamber to maintain combustion therein.

3. A power burner having pressure air and oil passage means therein, and having a vaporizing chamber supplied from said oil passage means and disposed out of the path of the air supply, means for heating said chamber to vaporize liquid oil supplied thereto by said oil passage means throughout the operation of the burner, and means forming a combustion chamber having an outlet delivering to a point remote from said vaporizing chamber and communicating with said vaporizing chamber, said air supply means delivering air entraining the vapor as it rises from said vaporizing chamber to form a combustible mixture burning in said combustion chamber 'and said air blowing the flame from the outlet 'of said vaporizing chamber through said combustion` chamber.

4. In combination, heating means', a burner having vaporizin'gmeans maintained at a vaporizing temperature by the heat of said heating means throughout the operation of the burner and also an upwardly opening cbmbustin chamber above and communicating with said Vaporizingxmeans at a point inside said burner and having an outlet at its top delivering at a point remeans and delivering the combustible mixture to.

said combustion chamber.

5. In combination, heating means, a burner having vaporizing means maintained at a vaporizing temperature throughout the operation of the burner by the heat of said heating means, and a chamber in said burner communicating with said vaporizing means and having fuel and air mixing means within said chamber, means for supplying fuel to said vaporizing means, and means for supplying air under pressure to said chamber including an air supply passage forming means extending through said vaporizing means into said chamber and discharging air entrainlng and forming a combustible mixture with said vapor as said vapor emerges from said vaporizing means into said chamber.

6. In combination, combined heating and igniting means, a burner having vaporizing means heated by said means to constantly maintain the burner in condition for starting, said burner also having passage forming means for delivering oil to said vaporizing means and passage forming means for delivering air under pressure for entraining the vapor as it emerges from said vaporizing means and also mixing the air and vapor and delivering the mixture for ignition by said heating and igniting means, and mechanism for starting and stopping the burner including devices for establishing and interrupting delivery of air and oil through said air and oil passage forming means.

7. A power burner having pressure air and oil passage means, a vaporizing chamber surrounding said pressure air passage means and receiving oil from said oil passage means and having an outlet at its top so disposed that the vapor generated in said chamber will rise under its own heat through said outlet,- and said burner also having an upper chamber positioned to receive vapor rising from said vaporizing chamber and having a constriction above and adjacent the outlet of the latter, and means for maintaining said vaporizing chamber throughout operation of said burner at a suiliciently high temperature to effect vaporization of oil supplied thereto, said air passage means supplying air under pressure to said upper chamber to effect entraining of the rising unburned vapor with said air supply as said vapor emerges from said'vaporizing chamber into said upper chamber to form an ignitable mixture burning in the latter.

8. A power burner having pressure air and oil passage means therein and having a vaporizing chamber surrounding said air passage means and adapted to be heated to vaporize oil in said chamber, and also having a. mixing and initial combustion chamber communicating with said vaporizing chamber at the top of the latter and in which burning takes place, the air from said air passage means entr-aiming the vapor as it emerges from said vaporizing chamber to form a combustible mixture in said chamber and said air passage means discharging an air stream blowing the flame upwardly in said combustion chamber, and vapor flow directing baille means in said chamber directing the vapor into the path of the moving air stream.

9. In combination, a power burner having a mixing and initial combustion chamber and vaporizing means of substantially smaller cross sectional area than the adjacent portion of said chamber `and delivering into the latter, means responsive to demands for more or less heat for delivering or stopping delivery of both fuel to said vaporizing means and air under pressure entraining and forming a combustible mixture in said combustion chamber of said air and the vapor rising from said vaporizing means into the air stream, and heating means for constantly maintaining said vaporizing means at an operating vaporizing temperature ready to start said power burner upon delivery of fuel and air as aforesaid.

10. In combination, a combustion chamber having an upwardly directed outlet delivering a flame upwardly into a re box, ar vaporizing chamber having oil heating and vaporizing passage forming means adjacent and disposed beneath and communicating with said combustion chamber, means for supplying air under pressure for entraining gaseous vapor emerging from. between said passage forming means and for blowing flame from adjacent said vaporizing chamber through said combustion chamber, means for so heating said passage forming means throughout the operation of the burner as to vaporize oil therein and ,cause gaseous vapor to rise and emerge from said vaporizing means to form a combustible -mixture with the air stream, and means located in said combustion chamber between the outlet thereof and the upper ends of said vaporizing chamber and air supply means for mixing the air and vapor into a combustible mixture.

11. In combination, an annular preheating burner including a burner base, a power burner connected to said base and having a vaporizing chamber extending centrally through and preheated by said annular burner and said power burner delivering flame upwardly within the flame of said annular burner, means for supplying oil to said preheating burner, and means for intermittently supplying both air and oil to said power burner to start and stop the latter while air supply means and a coaxially disposed fuel vaporizing chamber for said power burner, and having said chamber heated by said outer burner and disposed out of the path ofl the air supply, and an upwardly opening chamber coaxial with and above said vaporizing chamber into which said air supply means discharges air and into which said vaporizing chamber discharges vaporized fuel.

13. In combination, a constantly operating outer burner delivering llame upwardly and having means for delivering vaporized oil thereto, and a cooperating power burner centrally disposed with respect to and preheated by said first mentioned burner and having vertical pressure air passage means in said power burner and a. coaxlally disposed fuel vaporizing chamber in said power burner and also having means forming a combustion chamber ln said power burner above said air passage means in which the vapor from saidvvaporizing chamber is burned for directing a llame upwardly with respect to said vaporizing chamber centrally within the flame of said i'lrst mentioned burner.

14. In combination, a burner having means for delivering vaporized oil thereto and also including coaxial perforated shells dening combustion spaces, and a power burner preheated by said first mentioned burner and having vertical pressure air passage means in said power burner and a coaxially disposed fuel vaporizing chamber in said power burner, said power burner being disposed coaxial with respect to said shells and also having a combustion chamber above said vaporizing chamber and in which vapor rising therefrom is burned and also having said combustion chamberextending upwardly within said shells and delivering the flame upward with respect to saic' vaporizing chamber.

l5. In combination, a substantially annular constantly operating burner having means for supplying vaporized oil'thereto and including an eccentrically disposed fuel supply connection and a central aperture, and a power burner in said aperture centrally disposed relative to said first mentioned burner and preheated by said first mentioned burner and having vertical air passage means and a fuel vaporizing chamber for said power burner coaxially disposed relative to said aperture, and a combustion chamber above said vaporizing chamber in which the mixture of air and fuel supplied to said combustion cham- Der is burned and having an outlet delivering the fiame upwardly from said vaporizing chamber.

16. In combination, a burner having vaporizing means for supplying vaporized oil thereto, a power burner preheated by said rst mentioned burner and having vertical air supply means and a fuel vaporizing chamber, and also having a central chamber in which partial combustion of said air and fuel takes place above said vaporizing chamber, said first mentioned burner having vapor conducting grooves surrounding said vaporizing chamber and the latter having its bottom disposed below the bottoms of said grooves, and a constant level fuel supply means common to both burners having fuel supply connections to said vaporizing means and to said vaporizing chamber.

17. In combination, a pair of cooperating burners including a power burner having an annular vaporizer and upwardly directed communicating air and flame passage forming means in said power burner coaxial with said vaporizer and a cooperating preheating burner having annular combustion chamber forming means relative to which said vaporizer is centrally disposed, and a burner base connected to said vaporizer and supporting said combustion chamber forming means and through which base said air passage forming means supplies air axially under pressure to said flame passage forming means.

18. In combination, an outer burner having va-l porizer means for vaporizing oil supplied thereto and communicating upwardly directed combustion chamber forming means, and a cooperating power burner within and preheated by said first mentioned burner and delivering flame in the same direction as said first mentioned burner and comprising coaxially disposed pressure air and oil passage means, a vaporizing chamber above and communicating with said oil passage means, and 'also comprising a combustion chamber communicating with said vaporizing chamber and of substantially greater cross sectional area than said vaporlzing chamber in the portion of said combustion chamber adjacent said vaporizing chamber and above the latter and said air passage means.

19. In combination, a preheating burner having vaporizing means and annular perforate shells disposed in vapor conducting grooves communicating with said vaporizing means, and a power burner extending centrally through said preheating burner, said power burner having a vaporizing chamber heated by said preheating burner and a pair of coaxially disposed tubular elements providing passages for pressure air and combustion products, one delivering pressure air for entraining and delivering for burning in said power burner the vapor rising from the vaporizing chamber of said power burner and the other carrying away the products of combustion from within said power burner.

20. In combination, a pair of cooperating distillate and power burners one within the other and each having vaporizing means and each having coaxial upwardly directed flame delivering means and said delivering means in said power burner having a bottom portion of greater cross sectional area. than the vaporizing means of said power burner, said distillate burner being so disposed as to heat the vaporizing means of said power burner and thereby maintain said vaporizing means ready to start said power burner in full operation upon delivery of oilto the vaporizing means thereof and air to mix with the rising vapor for burning within said flame delivering means of said power burner, and mechanism controlled by demands for more or less heat including intermittently operating starting and stopping means for supplying oil and air under pressure .to cooperate with the vaporizing means of said power burner.

LYNN OTIS SELBY.

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