US2315172A - Means of atomizing liquids - Google Patents

Description

March 30, 1943. V ORHE.S 2,315,172

MEANS OF ATOMIZING LIQUIDS Filed Dec. 9, 1940 2 Sheets-Sheet 1 VINVENTOR. 7555p TV March 30, 1943. J. T. VooRHQS 2 Sheets-Sheet 2 Filed Dec. 9, 1940 INVENTOR. 75 7.' Vowel-151$ Patented Mar. 30, 1943 UNITED res PTENT OFFICE 1, Claim.

This invention relates to oil burners especially adapted for use in power plant installations, and particularly pertains to a means of atomizing liquids.

In the operation of oil burners of the straight mechanical or pressure type the oil burner atomizes by pressure only. It is of course requisite that the oil shall be heated to reduce its viscosity to approximately 150 S. S. U. or less, except when the normal viscosity of the oil is sufficiently low such as is usually the case when an oil of 28 Be. or A. P. I. gravity or less is used. It is characteristic of oils having such viscosity limits to atomize them under straight pressure. This places a limit on the oil burning capacity range of a burner having tips of any selected size since oil must be delivered under a minimum pressure sufficient to produce proper atomization, after which the capacity can only be increased by increasing the pressure. The formula expressing this phenomena is that the quantity of oil which is atomized with a given size tip varies as the square root of the pressure on the oil, thus in order to double the capacity of the fire without changing the tip it is necessary to multiply the pressure four times. It will be recognized that in varying the pressure the atomizing effect is directly varied in a straight pressure type oil burner. It is desirable to maintain a constant atomizing effect throughout the entire range of pressure while using a given size burner tip. It is the principal object of the present invention, therefore, to provide a method and means of atomizing fuel oil whereby pressure may be applied to the oil and it may be atomized, and by which method the atomization will be maintained uniformly throughout the range of capacity of the burner tip.

The present invention contemplates the provision of an oil burner having a pressure pump for delivering liquid fuel under pressure to an atomizing nozzle from which it is ejected in an atomized spray, the structure including a novel type of nozzle tip and means for permitting a surplus flow of the liquid fuel to return to the source of fuel supply while controlling the fuel pressure.

The invention is illustrated by way of example in the accompanying drawings, in which:

Figure 1 is a View in side elevation showing the general application of the present invention. Fig. 2 is an enlarged fragmentary View showing the fuel supply conduits and a form of nozzle structure embodying the use of a single nozzle tip. Fig. 3' is a view in transverse section through the nozzle tip as seen on the line 33 of Fig. 2. Fig. 4 is a View in transverse section through the nozzle tip as seen on the line 44 of Fig. 2. Fig. 5 is a view in transverse section through the nozzle tip as seen on the line 5-5 of Fig. 2. Fig; 6 is an end view showing a form of the invention in which three nozzles are used.

Fig. '7 is a view in central longitudinal section as seen on the line 1-1 of Fig. 6.

Fig. 8 is a view in transverse section showing the nozzle ducts as seen on the line 88 of Fig. 7.

Fig. 9 is a view in transverse section showing another form of invention having a simplified nozzle.

Referring more particularly to the drawings, ill indicates a T-connection to which a conduit H is connected leading from a suitable source of liquid fuel. A tubular feed pipe I2 is connected to the discharge side of this conduit and leads to a nozzle head l3. This nozzle head is disposed at a desired position within a heat chamber and within which combustion of said fuel is to take place. The nozzle head l3 includes a cylindrical body member I4 which is of substantially greater diameter than the feed pipe I2. This body memher is formed with a central bore i5 at its outer end into which the feed pipe I2 is threaded. Drilled longitudinally of the body member at opposite sides of the bore l5, and shown in Figs. 2 and 3 as being in diametrically opposite sides of the body member, are longitudinal passageways it. the outer end of the bodymember [4 but do not extend entirely through the body member. The innermost ends of these passageway are. closed by threaded plugs H which may be removed when it is desired to clean the burner head. f At the forward end of the body member I4 is a counterbore having a threaded inner end [B and a smooth cylindrical outer bore H). An inclined lip 20 is formed around the forward end of the outer bore to provide a conical seat for a purpose to be hereinafter described. The bore 19 is relatively large in diameter and is provided with radial ducts 21 which form a fuel passageway between the longitudinal passageway l6 and the bore 19. This construction is shown in Figs. 2 and 3 particularly. At the ends of the passageways IG adjacent to the plugs ,ll radial ducts 22 are provided and extend into the, bore l5. These permit the liquid fuel to flow from the feed pipe I2 through the ducts 22 and along the passageway It to the ducts 2| and then into the bore {9.

Extending through'the bore l9 and threaded into the bore'l8 of the body member M is an These passageways terminate adjacent to .hexagonal portion are greater than the dimensions of the bore l9 so that the hexagonal end of the tip projects beyond the endface 26 of the.

body l4. Its. back face, as shown at 21, is inwardly tapered and seats against the tapered face 2|] in the end of the body member l4. As shown in Fig. 3 of the drawings, the cylindrical body of the main nozzle tip 23 is formed with a pairxof diametrically disposed tangential ducts 28 which v communicate with a, central cylindrical bore 29 within the cylindrical body 24 of the main nozzle j tip. The central cylindrical bore has an outer conical face 30 which communicates with a central restricted jet opening 3|. This jet opening occurs at the apexof the bore. The cylindrical portion12'4 of the main tip 23 is formed with a threadediend .which screws into the bore I8 of the body member M. A continuationof the central bore 29. of the main nozzle tip provides an enlarged smooth cylindrical bore length 32 terminating'in a threaded portion 33. The juncture .of the bores 29 and 32 is represented by a transverse shoulder 34. At points midway the length of the wall: section circumscribing the bore portion '32 radial ducts 35 are formed. These ducts, as shown in Fig. 4 of the drawings, establish communication between a space 35 which occurs between the cylindrical portion of the main nozzle tip 23 and the bore section 32 and the central bore 29 of the main nozzle tip.

Mounted withinthe main nozzle tip 23 is an innernozzle tip 31. The inner nozzle tip 31 comprises'a threaded base 38 having a reduced portion 39 which causes anannular space to occur within the bore 29 and'therearound. An annular groove 40 is formed in the outer circumference of the portion .39 of the inner nozzle and lies in the plane of the'ducts 35. Tangential ducts 4| extendinwardly fromv said groove through the wall of the inner nozzle and terminate in a central whirling chamber 420f the inner nozzle. The base member 33 of theinnernozzle has'a shoulder which abuts against the shoulder 34 within'the main nozzle tip. The inner nozzle is formed with a tubular tip portion 43 within which thebore' 42 occurs. This tubular tip has a tapered end'conforming to the taper 35 of the outer noz-v zle. Thus, a whirling chamber 44 for the outer nozzle is formed between the inner nozzle tip 43 and the walls 29 and 35 of the main nozzle tip. A plurality of return ducts 45 extend longitudinally through the base portion 38 of the inner nozzle tip and establish communication between the whirling chamber 44 of the main nozzle and the open end of the bore 33;; V bore 5 of the body member I4 is indicated at 46. This extension is of reduced diameter and communicates with the threaded bore |8 of the body member. A return pipe 41 telescopes through the feed pipe'IZ and projects through the bore 46 with a tight slip fit. The central bore 42 in the inner nozzle jet is fitted with a restricted discharge opening 46 at its forward end. The opposite end of the bore is partially closedwith a threaded plug 49 which is formed with a central bleeder duct 50 .therethroug'h. In the form of the invention shown in Fig. of. the drawings a feed pipe I? and the return An extension of the pipe 41 are carried on a burner head 5|, the end of which is formed with three facets 52. These facets are disposed in inclination to the normal plane of the end of the burner body. Carried in each facet is a nozzle structure as shown and described in Fig. 2'. The end of the feed pipe I2 communicates with a distributing chamber 53 within the head 5|. Distributing passageways 54 lead diagonally from the chamber 53 and terminate near the forward end of the head 5|. A lateral passageway 55 establishes communication between the passageways 54 and the annular space l9. Return passageways 55 lead from the end of the bore l8 to a chamber 51 which is in communication with the return pipe 41.

I n the form of the invention shown in Fig. 9 a modified form of the invention is shown in which 3 main nozzle tips 58 are provided and are fed from a main passageway 59 through distributing ducts B0. The nozzle tips 58 are formed with a central bore 6| which terminates at its outer endin a conical end portion 62 from whichla discharge orifice 63 leads. Extending through the side walls of the nozzle tip are radial or tangentially arranged ducts 64 which communicate with a circumscribing chamber v65.. The .chamber 65 is in communication with the distributing ducts 60. The nozzle tips 58 are formed with an enlarged head portion 66, similar to that disclosed in the other views of the drawings, this head having a tapered shoulder 61 fitting in a tapered counterbore 68 of the chamber 65. A threaded bore 69 forms a continuation'of the chamber 65 and re-. 'ceives' the portion of. the nozzle tip. In this particular form of the'invention a plug 10 is inserted into the nozzle tip bore El and is held in position by a pin II. In the form of nozzle tip construction disclosed in Fig. 9, as vwell as the more complicated nozzle tips shown in the other figures of the drawings, it will be recognized that the entire nozzle tip structure is a separate unit, which may be quickly placed in position in the head of the burner structure or removed therefrom as a unit. Due to this arrangement no adjustment of th tips is necessary when or after they are installed. 1

In operation of the presentinvention and with the pump through the feed pipe l2 and along the outside of the return pipe 47. The fuel oil then passes through the ducts 22 in the nozzle head M to and through the longitudinal passageways It. The fiow of fluid thencontinues through the radial passageways 2| to the annular space l9 which occurs around the main nozzle tip 23. The fluid then flows through the tangential jets 2a to the whirling chamber 44. Here it will be given a spinning actionas it passes around the inner tip. It will be forced outwardly through the jet opening 3| in the 'end of themain nozzle. At

the same timea portion ofthe oil which is delivered to the annular space I9 will pass through the tangential ducts 4| and intothe central bore 42 of the inner tip. This will cause a second jet of oil to be created which is projected into the center of the first jet of oilasthe two jets. emanate from the jet opening 3| in the main nozzle. Surplus oil which does not pass through the constrictions formed by the innerjet opening 48 and the outer jet opening 3| will flowto the return pipe 4! throughthe return ducts 45 and 50. The

rate of return flow of the oil is controlled by a V valve 12. It will be seen that the nozzle structure creates two jets of commingling fluid. The tangential ducts 28 and 4| are arranged to cause both sprays to spin in the same direction. The object of the inner spinning spray is to insure thorough atomization of a given quantity of oil without widening the spray angle and while acting upon a minimum volume of fuel oil.

Attention is directed to the fact that the main nozzle tip and the inner nozzle tip are disposed concentrically and that the inner tip is nested within the outer tip. The jet opening 3| of the main tip and the jet opening 48 of the inner tip are in communication with the whirling chamber 44 of the outer nozzle and the chamber formed by the central bore of the inner nozzle, respectively. A whirling action is imparted to the oil delivered to both of said chambers and causes a jet of oil to be projected outwardly through the discharge opening 48 of the inner tip, and then through the discharge opening 3| of the main tip. Thus, atomized oil is discharged from the opening 3| in the main tip, which oil in reality is in two jets, an outer spray jet created by the oil from the whirling chamber 44 and an inner spray jet created within the inner nozzle. It has been found that the action of the inner spray jet tends to prevent the widening of the spray angle as the amount of oil discharged through the final orifice 3| is reduced. In cases where the oil supply is reduced to create a minimum size fire it appears that a hollow space is formed in the main whirling chamber 44, and that the spray from the inner tip strikes this film of oil along the tapered face 30 leading to the final discharge orifice 3| of the main tip. This acts to slow the film of oil down so that the centrifugal force created in spinning the oil in the chamber 14 will not be sufiicient to greatly widen the spray angle. It will therefore be seen that as the valve is regulated the pressure within the nozzle head will be established, and that this re ulation does not depend upon restricting the inflow of fuel oil through the pipe l2. That flow of oil is established by the operation of the fuel pump I0. By this arrangement, therefore, any given volume of oil is delivered to the nozzle while the proportion of oil atomized and discharged from the nozzle is controlled by regulation of the return valve 12. Attention is directed to the fact that the oil returning from both nozzle tips will pass through the return pipe 41 and its pressure will be regulated by the return valve 12.

Referring to the form of the invention shown in Figs. 6 to 8, inclusive, the operation and control of the nozzle is the same as previously described with the exception that there are a plurality of nozzles to which the fuel oil is simultaneously fed and from which the surplus oil is allowed to escape through the return pipe 41 as regulated by the valve 12. The form of the invention shown in Fig. 9 functions in the same manner save that there is no inner nozzle and no return feature.

It will thus be seen that the invention here disclosed provides a nozzle structure in which a high ratio of pressure to fuel oil may be created and regulated, and whereby thorough atomization may be brought about at all times over a capacity range of a particular nozzle while varying the nozzle capacity to meet the demand of the equipment with which it is used.

While I have shown the preferred method and means of atomizing a fuel oil and controlling the volume of oil being atomized, it is to be understood that various changes might be made in the steps of the method and the combination, construction and arrangement of parts by those skilled in the art without departing from the spirit of the invention as claimed.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

In combination, a burner head including a cylindrical body member having longitudinal passageways therein closed .at opposite ends, a central passageway therethrough open at its opposite ends, the inner end of said passageway receiving a fluid supply pipe of relatively large diameter, the opposite end of said passageway being formed with a smooth cylindrical bore continuing with a threaded bore, said threaded bore communicating with a length of passageway of reduced diameter, a return pipe fitted within said length of passageway of reduced diameter and extending longitudinally of the supply pipe, said return pipe being suiiiciently less in diameter than the supply pipe as to form an annular passageway between the pipes for the flow of liquid fuel, radial passageways leading from said annular space to the longitudinal passageways in the body member, radial passageways at the outer end of said longitudinal passageways establishing communication between said passageways and the smooth cylindrical bore in the body member, a main burner tip extending through said smooth cylindrical bore and being screwed into the threaded bore of the body member, the outer end of said burner tip closing the outer end of the cylindrical bore, whereby an annular chamber will occur around the burner tip, a central cylindrical bore within the burner tip in substantially the same plane as that of the smooth cylindrical bore of the body member, the outer end of said central cylindrical bore continuing in a frustoconical wall converging outwardly and centrally of the burner tip, a restricted discharge opening at the apex of said wall section, tangential ducts through the wall of the burner tip establishing communication between the cylindrical bore within the body member and the cylindrical bore within the burner tip, an inner burner tip mounted within the bore of the outer burner tip and spaced from the walls thereof, said inner burner tip having means to close the cylindrical bore within the outer burner tip at the inner end thereof. the forward end of said inner burner tip being frusto-conical and spaced from the frusto-conical section of the bore of the inner burner tip, a relatively small discharge passage in the end of the inner burner tip in axial alignment with the discharge passage in the outer burner tip, tangential ducts in the walls of the inner burner struc ture for delivering liquid to the central passageway thereof, ducts through the wall of the outer burner tip communicating with the annular bore in the body member and the last said tangential ducts to supply oil to the inner burner tip and return ducts establishing communication between the interior of the inner burner tip and the return pipe and the interior of the outer burner tip and the return pipe.

JOSEPH T. VOORHEIS.

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