US2568880A

US2568880A - Oil burner nozzle

Info

Publication number: US2568880A
Application number: US22379A
Authority: US
Inventors: Cecil R Waldron
Original assignee: EUREKA WILLIAMS CORP
Current assignee: EUREKA WILLIAMS Corp
Priority date: 1948-04-21
Filing date: 1948-04-21
Publication date: 1951-09-25
Anticipated expiration: 1968-09-25

Description

Sept. 25, 1951 c. R. wALDRoN OIL BURNER NOZZLE Filed April 2l, 1948 Patented Sept. 25, 1951 UNITED STATES PATENT OFFICE 3 Claims.

This invention relates to fuel and air mixing nozzles adapted for use in forming a primary mixture to be burned in a blast of secondary air, such nozzles being useful particularly in connection with low-pressure type oil burners.

An object of the invention is to provide a better and a more quiet and eicient nozzle for use in connection with the formation of a primary mixture in loW pressure type oil burners.

Other and further objects of the invention will be apparent by reference to the accompanying drawings of which there is one sheet, which, by way of illustration, shows a preferred embodiment and the principles thereof and what I now consider to be the best mode in which I have contemplated applying these principles. Other embodiments of the invention embodying the same or equivalent principles may be used and structural changes may be made as desired by those skilled in the art without departing from the present invention and the purview of the appended claims. I also contemplate that of the several different features of my invention, certain ones thereof may be advantageously employed in some applications separate and apart from the remainder of the features.

In the drawing:

Fig. 1 is a fragmentary view illustrating an oil burning furnace employing a low-pressure type oil burner having a primary fuel and air mixing nozzle embracing the principles of the invention;

Fig. 2 is an enlarged longitudinal sectional View of a part of the primary fuel and air mixing nozzle embraced in the structure disclosed by Fig. 1;

Fig. 3 is a cross sectional view through the fuel and air mixing nozzle illustrated by Fig. 1. Fig. 3 is taken substantially in the plane of line 3-3 of Fig. 1; and

Fig. 4 is another cross sectional view through the nozzle illustrated by the preceding figures, except that Fig. 4 is taken substantially in the plane of line 4 4 of Fig. 2 with the forward end of the inner tubular body embraced in the nozzle shown in end elevation.

Referring particularly to Fig. 1, the numeral I indicates generally an oil burning furnace having a combustion chamber II which is surrounded by a wall I2 having an opening I3 formed therein for the reception of an air cone or nozzle member I4 through an orifice I6 in which a blast of secondary air is supplied to the combustion chamber II. Disposed outwardly of the orifice I6 and concentrically relative thereto isa primary fuel and air mixing nozzle I'I having an orifice I8 formed concentrically Within the front end thereof and through which orifice a blast consisting of a primary mixture of fuel and air is discharged into the combustion chamber Il concentrically with respect to the blast of secondary air supplied by the orifice I6. The nozzle I'I consists of an outer tubular body or member I9 having a front Wall ZI in which the orifice I8 previously referred to is formed.

The inner surface of the wall 2I is frusto-conical in formation, as is indicated at 22, the orifice I8 being formed at the smaller end of the surface 22 which forms a knife edge around the periphery of the orifice I8.

Rearwardly of the surface 22, the interior of the body I9 is of cylindrical formation as is indicated at 23, the cylindrical surface 23. being adapted to receive and to closely i'lt the exterior cylindrical surface 24 of an inner tubular body 26. The forward end of the inner tubular body 26 is provided with an annular frusto-conical seat indicated at 2l which is adapted to engage the surface 22 at the base thereof to provide within the front end of the outer body I9 a tip chamber 28 communicating with the orice I8.

Within the annular seat 2l the forward end of the inner body 26 is provided with a planular annular surface indicated at 29 and from the central portion of which a conical tip indicated at 3| projects toward the orice I8 in concentric relation thereto.

Beyond the annular seat 27 the inner body 26 has formed within the exterior cylindrical surface thereof a plurality of longitudinally disposed channels or air and fuel mixing chambers indicated by the numeral 32. The inner surfaces of the chambers or channels 32 are plane surfaces which extend in opposite directions toward the inner cyiindricalpsurface 23 of the outer body I9 and at the ends of which are paralleled chanel side walls, the outer edges of which terminate in the exterior cylindrical surface 2li of the inner body 26. Between the vchannels 32 which are equally spaced about the circumference of the inner body 26, the exterior cylindrical surface of the inner body 2B provides a plurality of longitudinally disposed arcuate seats indicated at 33 which engage and form a relatively fluid tight iit with the inner cylindrical surface 23 of the outer body I9. The forward ends of the fuel and air mixing chambers 32 terminate at the seat 21 and are connected with the tip chamber 28 across 3 the seat 21 by angularly disposed passages 34 which are formed in the front end of the inner tubular body 26.

The cross section of the passages 34 is not as great as the cross section of the air and fuel mixing chambers or channels 32, so as to increase the velocity of the primary fuel and air mixture to be formed in the chambers 32 as this mixture moves through the passages 34 from the chambers 32 to the tip chamber 28. The passages 34 are eccentrically related to the end of the inner tubular body 26 and the tip chamber 28, the forward ends of the passages 34 terminating within the tip chamber 28 within the annular surface 29 and in eccentric relation to the tip chamber 28. The rear ends of the passages 34 also terminate in thelforward ends ofthe chamber 32 in eccentric relation to the latter chambers and midway between the side walls thereof.

The inner body 26 is provided with a liquid fuel supply passage 38 formed internally and toward the front end thereof, the passage 36 being connected to the chambers 32 intermediate the ends thereof by a plurality of radially disposed fuel supply ports 31. The outer ends of the ports 31 which terminate within the central portions of the channels 32 are formed with relatively sharp edges so as to tend to divide and to atomize fuel which may be discharged from the ports 31 into the air which moves forwardly within the `channels 32.

Air ata relatively low pressure is adapted to be supplied to the channels 32 by a conduit 38 which projects from the casing 38 of a low pressure type oil burner which is provided with a pumping unit adapted to supply fuel and air to the nozzle I1 'at approximately the same pressures. The oil burner also is provided with a fan for supplyingsecondary air which is discharged into the combustion chamber II c through the orifice I8. For a morel complete description of an oil burner system of this type and the primary and secondary air, and the fuel pumping, metering and fanmechanism employed therein, reference may .be had to the co-pending applications for UnitedStates LettersPatent of Howard E. Earl, Serial No. 2,881, led January l1, 19 18, for Oil Burner System, now Patent ANo. 2,554,481, issued,` May 29,1951; Howard MEI. Earl, Serial No. 772,970,1,led VSeptember 9, 1947,4f7or MotorCompressonUnit, now PatentNo. 2,542,- 121; and Robert R. WitherelhuSer. No. 13,718, filed March 8, 1948, for Oil Burner Pumping Unit. d

The nozzle I1 'removably secured to the threaded end of the conduit 38 by a coupling member 4I. Within the conduit 38 and also connected to the oil burner pumping unit referred to is a'noil supply conduit 42 which supplies oil to the 'cavity or passage 36 of the nozzle I1 through a 'tube 43. The tube 43 is removably positioned at `its opposite ends within the cavity 35 and the interior of the conduit 42. Surrounding the tube `43 is a spring 44 which `en-4 gages the 'adjacent ends -of the conduit 42 and the 'inner body 26, this spring being adapted to resiliently Yposition the inner body 28 within the outer body I8 with the annular seat 21 in engagement with the front wall 2I of the outer body IS.

The volume of the primary air supplied by the conduit 38 is several times the volume of fuel supplied by the conduit 42, the ratio 'between these quantities of fuel and air vbeing whatever ratio may be desired to produce the primary mixture required.

From the conduit 38 the air supplied to the fuel and air mixing chambers 32 moves forwardly within the mixing chambers toward the passages 34. As the air passes over the sharp outer ends of the ports 31 the air picks up and moves along the interior surfaces of the chambers 32 the quantity of fuel required for producing the primary mixture. The fuel and air so proportioned moves forwardly from the ports 31 at approximately the velocity of the air supplied t the opposite ends of the chambers 32 until the forward ends of these chambers are reached. In such regions the fuel and air mixture in the chambers 32 passes over the edges defining the rear extremities of the passages 34, thereby further tending to divide and to atomize the fuel content of the mixture. Due to this reduced cross section 'of the passages 34, the mixture V,so described as moving forwardly within the chambers 32 increases in velocity in the passages 34 thereby tending to increase the atomizaton of the fuel and air mixture and to prevent a separation of the fuel from the air before the mxtureis discharged into the tip chamber 28. Owing to' the eccentric relation between the passages 34 and the

chambers

32 and 28, the mixture from the passages 34 is discharged into the tip chamber 28 in such manner as to rotate the fuel and air mixture within the tip chamber 28. From the tip chamber 28 the mixture isn discharged over the knife edges of the orifice I8 in a blastV of fuel and air which moves forwardly through the orifice I6 into the combustion chamber II in concentric relation to the secondary 'air also discharged in a blast through u*the* ori'ce IG. During the discharge of the oil and air mixture lfrom the orice I8, the cnical tip 3| which projects within the orifice y serves Athe purpose of preventing the formation of large drops of oil in the nozzle during the operation thereof. The tip y3| which projects Ainto the orifice `I8 progressively increases f the velocity of 'the 01'1 anu air mixture as it approaches passes over the knife edge of the orifice I8, thus 'causing a finer break-up of the fuel oil particles as the mixture vis discharged from 'the orifice I8 and into and through the orifice )16.

1 It will lbe 'noted that the 'slope of the surface of the ltip 3| is -greater than the slope of the surface 22 forming the inside of the front end N2'I of the body 'I8. Under Vsuch circumstances 'the 'cross sectional Varea o'f Athe tip chamber 28 therefore decreases 'frein the front end of the body 25 to the knife edge orifice I8. Under s'uch circumstances, Jth'e 'rotating body vo'f fluid forming the mixture in the 'tip 'chamber 28 will increase in `velocity as vit approaches the knife edge orifice I8 and the apex of the tip 3 I.

The relation between the cross sectional varea V'of the air supply 'and mixing chambers 32, the 'eccentric passages 34, and the size and shape of the Vtip 'chamber 28 is Vsuch 'that 'the velocity of the fluid inthese chambers as 'it moves toward the knife edge orifice `I'8 'progressively increases.

Beyond the nozzle I1 'the V'primary air and fuel and the secondary Vair nmixture so formed 'may be ignited by electrodes indicated at 46 for forming la. suitable -fire within the combustion chamber I I.

When the oil burner 'controls are operated in such manner as to discontinue the supply of fuel andair delivered to the nozzle I1 by the conduits 3^8 and 42, the conical tip 3| within the tip chamber 28 will tend to collect and to prevent the discharge from the orifice I8 of any large drops of fuel which otherwise might drip from the end of the nozzle H.

While I have illustrated and described a preferred embodiment of my invention, it is understood that this is capable of modification, and I therefore do not wish to be limited to the precise details set forth, but desire to avail myself of such changes and alterations as fall within the purview of the following claims.

I claim:

1. An oil burner nozzle comprising an outer tubular body having a circular sharp edged orifice formed coaxially therewith at the front end thereof, an inner tubular body within said outer body and having a front end formed to provide an annular seat disposed in engagement with said outer body and being spaced from said outer body at the front side of said seat to provide a tip chamber communicating with said orifice, said front end of said inner tubular body having a conical tip disposed within said tip chamber and projecting toward said orifice concentrically with respect thereto, said inner body on the side of said annular seat remote from said tip chamber being formed to provide a plurality of seats engaging the interior of said outer body and a plurality of longitudinally disposed air supply and mixing chambers between said seats, one of said bodies being formed to provide a plurality of passages across said annular seat extending between said air supply and mixing chambers and said tip chamber, said passages being of less cross-sectional area than said air supply and mixing chambers and being formed in sloped relation to said air supply and mixing chambers and said tip chamber with the forward ends of said passages terminating within said tip chamber and the rearward ends thereof terminating in said air supply and mixing chambers, said passages being disposed in directions eccentrically of said tip chamber so that said passage ends open into said tip chamber in a -direction for inducing the rotation of fluid in said tip chamber, a plurality of spaced oil supply ports extending between the interior of said inner tubular body and said air supply and mixing chambers and through which oil supply ports oil is supplied to said mixing chambers, the outer ends "of said ports forming relatively sharp edges across said latter chambers facing the direction of flow of fluid in said latter chambers, said air supply and mixing chambers supplying air for mixture with the oil supplied through said oil supply ports.

2. An oil burner nozzle comprising an outer tubular body having a circular sharp edged orice formed coaxially therewith at the front end thereof, an inner tubular body within said outer body and having a front end formed to provide an annular seat disposed in engagement with said outer body and being spaced from said outer body at the front side of said seat to provide a tip chamber communicating with said orifice, said inner body on the side of said annular seat remote from said tip chamber being formed to provide a plurality of seats engaging the interior of said outer body and a plurality of longitudinally disposed air supply and mixing chambers, said inner body being formed to provide a plurality of passages across said annular seat between said air supply and mixing chambers and said tip chamber, said passages being of less cross-sectional area than said air supply and mixing chambers and being formed in sloped relation to said air supply and mixing chambers and said tip chamber with the forward ends of said passages terminating in equally spaced relation within said tip chamber and the rearward ends thereof terminating in said air supply and mixing chambers, said passage ends opening into said tip chamber in a direction related to said tip chamber for inducing the rotation of fluid in said tip chamber, a plurality of spaced oil supply ports extending between the interior of said inner tubular body and said air supply and miX- ing chambers and through which oil under pressure is supplied to said air supply .and mixing chambers, the outer ends of said ports forming relatively sharp edges across said latter chambers facing the direction of flow of fluid in said latter chambers, said air supply and mixing chambers supplying air under pressure for mixture with the oil supplied through said oil supply ports.

3. A nozzle according to claim 1 wherein the relation between the cross sectional area of the air supply and mixing chambers, said passages and the size and shape of the tip chamber is such that the velocity of the fluid progressively increases as it moves toward the knife edge orifice.

CECYIL R. WAIDRON.

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

UNITED STATES PATENTS Number Name Date 1,227,867 Young May 29, 1917 1,934,755 Williams Nov. 14, 1933 2,055,864 Harsch Sept. 29, 1936 A 2,249,482 Macchi July 15, 1941 FOREIGN PATENTS Number Country Date 82,573 Sweden June 28, 1932 87,106 Austria Jan. 25, 1922