US2578422A - Burner for liquid fuel operating under low air and fuel pressures - Google Patents

Description

De- 11, 1951 E. J. F. GUlLLoT BURNER FOR LIQUID FUEL. OPERATING UNDER LOW AIR AND FUEL PRESSURES Filed oct, 21, 1947 ATTORNEYS Patented Dec. 11, 1951 BURNER FOR LIQUID FUEL OPERATING UNDER LOW AIR AND FUEL PRESSURES Etienne Jean Francois Guillot, Rives, France Application October Z1, 1947, Serial No. 781,058 In France October 22, 1946 6 Claims.

My invention has for its object a burner adapted more particularly though not exclusively for the burning of a heavy oil while using as cumbustive material low pressure air.

My invention relates more particularly to a burner of the type disclosed wherein the liquid fuel escapes from the burner nozzle under the form of a fluid annulus and is submitted to the action of an inner draught of air that expands it into a thin film and then to the action of an outer current of air ensuring final atomization.

The burner according to the present invention constitutes an improvement on the burner of the above disclosed type. It allows the perfect carburetting of large amounts of fuel reaching up to several hundreds kilos of fuel oil per hour and per burner while using as combustive material low pressure air the pressure of which may be as low as that of 15 mm. of water. It simplifies moreover the automatic control of the rate of combustion.

Tothis purpose, the burner according to the invention includes in association two primary coaxial nozzles each ending with a conical member followed by the cylindrical nozzle carried by a pipe and cooperating each with a secondary nozzle of corresponding shape while an admission of oil is provided between the inner wall of the primary nozzle and the outer wall of the secondary nozzle in association with two admissions of air constituted respectively by inner streams of air opening into the corresponding secondary nozzles and with a third outer stream of air that is fed between the outer wall of -the outermost primary nozzle and a casing surrounding the latter at a certain distance therefrom, said latter elements being shaped in a manner such as to produce an outer annular stream of air assuming a gyratory movement generating a depression inside said stream which converges towards the axis of the burner; the whole system is designed in a manner such that the two Coaxial oil rings escaping from the terminal openings of the two rst mentioned coaxial primary nozzles may be rst expanded and drawn out into very thin lms by the pressure produced by the inner streams of air and the depression produced by the outer streams of air, after which they are atomized by l said outer streams of air.

According to a further feature of the invention a further nozzle cooperating with the outer nozzle Y and constituting therewith the outer system forms at the same time a casing surrounding the nozzle of an inner system in such a manner that the inner stream of air of the outer system may form 2 at the same time the outer stream of air for the inner system.

Further features and advantages of my invention will appear in the reading of the following description given out with reference to accompanying diagrammatic drawing including a single figure illustrating in longitudinal cross-section a burner according to the invention.

In the drawing, 2 designates a primary nozzle mounted at the end of a pipe 3 and cooperating with a secondary inner noozle 4. The front part of the nozzle 2 is a frustoconical part 5 followed by a cylindrical end portion 6 cooperating with similar parts provided on the inner secondary nozzle. Outwardly, the nozzle 2 is surrounded at a certain distance by an outer nozzle l the opening 8 of which is directed towards the firebox.

rThe rear end of the nozzle 2 is shaped so as to form a channel or gap 9 between the inner wall of the nozzle .2 land the outer wall of the inner secondary nozzle. This channel communicates with an input pipe for liquid fuel I2. For regularizing the now of fuel, a ring Ill provided with perforations i I is fitted in the channel The hollow inner portion I3 of the secondary nozzle communicates with a bent pipe I4 the arm i5 of which communicates with a main air feeding pipe Il.

The nozzle 2 is stationary while the secondary nozzle 4 is adapted to move in a longitudinal direction. vTo this purpose the secondary nozzle 4 slides inside a stuffing box lll preventing oil leaks. The bent pipe I4 or more exactly its arm I5 is adapted to slide in a stuing box I6 that is airtight. The longitudinal movement of the secondary nozzle l is controlled by the handwheel 2i that is rotatably carried at 22 inside the stationary body of the burner. The hub of the handwheel 2I is provided with a threaded bore 23 cooperating with the outer thread 24 on a projection rigidv with the pipe Isl. A pointer 48 cooperating with a scale 49 carried by the hub of the handwheel 2| allows defining the position of the latter.

The current of air passing through the bent pipe I4 may be adjusted through a shutter I 8 that is movable round a spindle I9 rigid with a crank handle 2U the position of which may be defined by means of suitable marks.

The channel l5 defined between the outer nozzle or casing 'i and the nozzle 2 communicates with the air-feeding pipe Il through the agency of a rotary shell or plug 38 that is rotatably carried inside a sleeve 39 and held in place by a nut 46 screwed over said sleeve 39. The angular position of the shell 3S may be adjusted by means of a handle fil rigid therewith. A pointer 122 mounted on the handle 5i cooperates with the scale 43 for allowing the angular location of the shell 3e to be readily ascertained.

A second primary nozzle 25 arranged coaxially with reference to the rst nozzle 2 has a shape similar to that of said nozzle 2. Said second inner nozzle 25 is mounted on the outer frustoconical end 25 of a pipe 25 and cooperates with a secondary nozzle 2l' of corresponding shape. A channel or gap 2S is formed between the inner wall of the nozzle 25 and the outer wall of the secondary nozzle El, said channel communicating with a fuel inlet pipe 3i. A ring 29 provided with perforations 3% is fitted in the channel 22 for regularizing the ow of fuel.

The nozzle 25, like nozzle E, is stationary whereas the associated secondary nozzle 21 cooperating therewith mayl be displaced longitudinally. To this purpose the rear end of the secondary nozzle El slides inside an oil-tight stuing-box 32. This movement is controlled by a handwheel rigid with a sleeve threadedly engaging a member carried by the bent pip-e lf3, the hub of the handwheel 34 engaging a base 556 rigid with the secondary nozzle 2.

The channel 33 inside the secondary nozzle 2 is connecte-d with a flexible pipe 3l.

The ends of the primary nozzles 2 and 25 are provided outwardly with helical blades dit and 46 respectively, that impress a gyratory movement to the currents of air passing over said nozzles.

The above-described burner operates as follows: when starting, the secondary nozzles 4 and 2l lie in the position illustrated in the drawing wherein the channels 9 and 28 for the fuel are closed. The shutter i8 and the shell 38 are also in a position wherein they close the admission of air respectively through I4 and I'I.

When the air blowing means is started, the air enters through the pipe I1, the arm I5 and the yielding pipe 37 the hollow part 33 of the secondary nozzle 2l of the inner system. The throttle valve or shutter I8 is then opened by means of the handle so as to admit air into the channel i3 between the two systems. The hand wheel 34 is then rotated in a direction such that the secondary nozzle 21 may be moved towards the right hand side of the drawing. Through such a movement an opening is established between the front ends of the nozzle 25 and of the secondary nozzle 21 through which the fuel from the pipe 3l and the channel is expanded and drawn out as a very thin film under the action of the inner stream of air passing through the channel 33 and of the depression produced by the outer current of air fed through the channel i4 and to which the blades 46 impress a gyratory movement. At a small distance from the end of the nozzle 25, the outer air stream which is directed obliquely with reference to the axis of the burner engages the ring shaped fuel mass in its expanded and drawn out forni and atomizes it into iine particles.

Lastly, the plug or shell 38 is rotated through the handle 4I so as to admit air into the channel formed between the nozzle 2 and the casing 1. Then the secondary nozzle 4 of the outer system is caused to recede by operating the hand wheel 2|. Through the opening thus established between the ends of the nozzle 2 and of its associated secondary nozzle 4 may pass fuel admitted from the pipe l2 through the channel il so as to form a second ring that is coaxial with the first ring of fuel escaping between the nozzle 25 and the secondary nozzle 2l therein. This second ring is also caused to expand and is drawn out by the inner pressure exerted by the stream of air admitted through the channel i3 and the depression produced by the outer current of air arriving through the channel 45 to which the blades 44 impress again a gyratory movement. This outer current of air is also directed obliquely with reference to the axis of the burner so as to take hold of the expanded fuel ring at a small distance from the end of the nozzle 2 and to atomize it into fine particles.

It should be noticed that each fuel ring is submitted on its inner side to the pressure of the air from an inner air stream and on the outside to the depression produced by an outer air stream, said depression being obtained by the shape of the nozzles and the gyratory movement of the air streams produced respectively by the blades 44 and 46.

Through the associated action of these air streams, the fuel rings are expanded and drawn out into very thin transparent lms. As soon as these films leave the zones of depression, they are atomized through the action of the outer air streams that are directed obliquely with reference to the axis of the burner and engage the rings or annuli at a certain distance to the front of the nozzle.

According to an important feature of my invention, the two systems forming the two fuel rings are associated in a manner such that the air stream on the inside of the outer system forms at the same time the outer stream for the inner system. The burner includes thus two systems constituted by a nozzle and associated secondary nozzle, each of which systems is fed with fuel by a separate pipe for forming a fuel ring, and three independent air streams acting on the fuel rings in accordance with the above disclosed principles.

The adjustment of the combustion rate is executed preferably by adjusting, in accordance with a substantial hit and miss operation either of the two systems producing the fuel rings. This is obtained advantageously by controlling both the handle 4l governing the admission of air into the outer channel 45 and a member not illustrated governing the admission of fuel into the channel of the outer system by a pyrometer, a thermostat or any like suitable means through the agency of magnetic or the like valves in a manner such that the outer system constituted by the primary nozzle 2 and its associated secondary nozzle 4 may operate either at full rat-e or at a very reduced rate or even be inoperative.

Of course the form of execution described hereinabove and illustrated in the drawings is given out solely by way of example and it is pos sible to modify in any desired manner the shape, arrangement and mounting of the different elements considered without widening unduly thereby the scope of the invention as dened in accompanying claims.

What I claim is:

1. 1n a burner for heavy liquid fuel, the combination of two primary nozzles having an unbroken wall and including frusto-conical ends opening coaxially in a same terminal plane perpendicular to their common axis, a hollow secondary nozzle having an unbroken wall and arranged coaxially inside each of the first mentioned primary nozzles, defining with the corresponding primary nozzle an annular gap and opening in the plane of the opening in the corresponding primary nozzle, the -inner primary nozzle lying inside the outer secondary nozzle and defining an annular space therewith, independent means for feeding heavy liquid fuel at low pressure into the annular gap separating each primary nozzle from the associated secondary nozzle inside same, means for feeding air under low pressure into the secondary nozzle located inside the inner primary nozzle, into the annular space defined between the outside of the last mentioned inner primary nozzle andthe inside of the secondary nozzle associated with the outer primary nozzle and further over the outer wall of the Vlast mentioned outer primary nozzle, and means for adjusting the relative output of the different jets of air under low pressure, fed through the innermost secondary nozzle, the space above mentioned and over the outer wall of the outer primary nozzle, deflecting means on the outer surface of the outlet ends of the two primary nozzles adapted to impart an angular movement of the air passing over the primary nozzle ends.

.2. In a burner for heavy liquid fuel, the combination of two primary nozzles having an unbroken wall and including frusto-conical ends opening coaxially in a same terminal plane perpendicular to their common axis, a hollow secondary nozzle having an unbroken wall and arranged coaxially inside each of the first mentioned primary nozzles, defining with the corresponding primary nozzle an annular gap and opening in the plane of the opening in the corresponding primary nozzle, the inner primary nozzle lying inside the outer secondary nozzle and defining an annular space therewith, independent means for feeding heavy liquid fuel at low pressure into the annular gap separating each primary nozzle from the associated secondary nozzle inside same, means for feeding air under low pressure into the secondary nozzle located inside the inner primary nozzle, into the annular space dened between the outside of the last mentioned inner primary nozzle and the inside of the secondary nozzle associated with the outer primary nozzle and further over the outer wall of the last mentioned outer primary nozzle, and means for adjusting the cross-sectional area of the gaps fed with fuel between each primary nozzle and the cooperating secondary nozzle.

3. In a burner for heavy liquid fuel, the oombination of two primary nozzles having an unbroken wall and including frusto-conical ends opening coaxially in a same terminal plane perpendicular to their common axis, a hollow secondary nozzle having an unbroken 'wall and arranged coaxially inside each of the first mentioned primary nozzles, defining with the corresponding primary nozzle an annular gap and opening in the plane of the opening in the corresponding primary nozzle, the inner primary nozzle lying inside the outer secondary nozzle and delining an annular space therewith, independent means for feeding heavy liquid fuel at low pres sure into the annular gap separating each primary nozzle from the associated secondary nozzle inside same, means for feeding air under low pressure into the secondary puzzle located inside the inner primary nozzle, into the annular space defined between the outside of the last mentioned inner primary nozzle and the inside of the secondary nozzle associated with the outer primary nozzle and further over the outer wall of the last mentioned outer primary nozzle and means for adjusting the admission of air over the outer wall of the outer primary nozzle and of fuel into the space between the outer primary nozzle and its associated secondary nozzle.

4. In a burner for heavy liquid fuel, the com bination of two primary nozzles having an unbroken wall and including frusta-conical ends opening coaxially in a same terminal plane perpendicular to their common axis, a hollow secondary nozzle having an unbroken wall and arranged coaxially inside each of the first mentioned primary nozzles, defining with the corresponding primary nozzle an annular gap and opening in the `plane of the opening in the corresponding primary nozzle, the inner primary nozzle lying inside the outer secondary nozzle and dening an annular space therewith, a common annular casing surrounding coaXially the different nozzles, independent means for feeding heavy liquid fuel at low pressure into the annular gap separating each primary nozzle from the associated secondary nozzle inside same, means for feeding air under low pressure into the secondary nozzle located inside the inner primary nozzle, into the annular'space defined between the outside of the last mentioned inner primary nozzle and the inside of the secondary nozzle associated with the outer primary nozzle and further over the outer wall of the last mentioned outer primary nozzle and over the inside of the casing, and means for adjusting the relative output of the different jets of air under low pressure.

5. In a burner for heavy liquid fuel, the combination of two primary nozzles having an unbroken wall and including frusto-conical ends opening coaXially in a same terminal plane perpendicular to their common axis, a hollow secondary nozzle having an unbroken wall and arranged coaXially inside each of the rst mentioned primary nozzles, dening with the corresponding primary nozzle an annular gap and opening in the plane of the opening in the corresponding primary nozzle, the inner primary nozzle lying inside the outer secondary nozzle and defining an annular space therewith, an annular casing surrounding coaXially the different nozzles, independent means for feeding heavy liquid fuel at low pressure into the annular gap separating each primary nozzle from theassociated secondary nozzle inside same, means for feeding air under low pressure into the secondary nozzle inside the inner primary nozzle, into the annular space dened between the outside of the last mentioned inner primary nozzle and the inside of the secondary nozzle associated with the outer primary nozzle and further over the outer vvall of the last mentioned outer primary nozzle and over the inside of the casing, and means for adjusting the cross-sectional area of the gaps between each primary nozzle and the cooperating secondary nozzle.

6. In a burner for heavy liquid fuel, the combination of two primary nozzles having an unbroken wall and including frusto-conical ends opening coaxially in a same terminal plane perpendicular to their common axis, a hollow secondary nozzle having an unbroken wall and arranged coaxially inside each of the rst mentioned primary nozzles, defining with the corresponding primary nozzle an annular gap and opening in the plane ofthe opening in the corresponding primary nozzle, the inner primary nozzle lying inside the outer secondary nozzle and defining an annular space therewith, independent means for feeding heavy liquid fuel at low pressure into the annular gap separating each primary nozzle from the associated secondary nozzle inside same, means for adjusting the longitudinal location of each secondary nozzle inside the corresponding primary nozzle, means for feeding air under low pressure into the secondary nozzle located inside the inner primary nozzle, into the annular space defined between the outside of the last mentioned inner primary nozzle and the inside of the secondary nozzle associated with the outer primary nozzle and further over the outer wall of the last mentioned outer primary nozzle, and means for adjusting the relative output of the different jets of air under low pressure fed through the innermost secondary nozzle, the space above mentioned and over the outer wall of the outer primary nozzle.

ETIENNE JEAN FRANCOIS GUILLOT.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,011,100 Zander Dec. 5, 1911 1,136,115 Frost Apr. 20, 1915 1,429,434 Jones Sept. 19, 1922 1,763,387 Beach June 10, 1930 1,965,465 Magowan July 3, 1934 2,214,568 Thomas Sept. 10, 1940 2,417,445 Finkel Mar. 18, 1947

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