US3093317A - Fuel injection nozzle - Google Patents

Description

June 11, 1963 H. c. SIMMONS ETAl. 3,093,317

FUEL INJECTION NOZZLE Filed Aug. 24, 1960 3 Sheets-Sheet 1 FIG. a 2

FIG. 2

INVENTORS. HAROLD C. SIMMONS 8| LAWRENCE B. O'SICKEY ATTORNEYS June 11, 1963 H. c. SIMMONS ETAL 3,0 ,3 7

FUEL INJECTION NOZZLE Filed Aug. 24, 1960 5 Sheets-Sheet 2 INVENTORS.

HAROLD c. SIMMONS a keWRENCE B. O'SICKEY GM,7IZLZ@ a ATTORNEYS J1me 1963 H. c. SIMMONS ETAL 3,0 7

FUEL INJECTION NOZZLE Filed Aug. 24, 1960 3 Sheets-Sheet 3 FIG. 6

INVENTOR. HAROLD C. SIMMONS Q LAWRENCE B. O'SICKEY B Y (3201M, Q Emma-9:99

ATTORNEYS 3,093,317 FUEL INJECTION NOZZLE Harold C. Simmons, South Euclid, and Lawrence B.

OSickey, University Heights, Ohio, assignors to Parker- Hannifin Corporation, Cleveland, Ohio, a corporation of Ohio Filed Aug. 24, 1960, Ser. No. 51,613-

7 Claims. (Cl. 239-453) The present invention relates generally as indicated to a nozzle and, more particularly, to a fuel injection nozzle for gas turbines and the like having combustion chambers into which liquid fuel is introduced in finely sub-divided spray form.

At the present time a popular form of nozzle for this purpose is the variable orifice nozzle having a springbiased pintle valve formed with a conical head adapted to cooperate with the sharp edge or seat of the discharge orifice formed in the nozzle body to provide a variable area annular passage through which the fuel is metered and sprayed. With such nozzle, the spray cone angle is determined by the conical head of the pintle valve, the

conical sheet of fuel breaking up into a spray beyond the base of the conical head. Generally, the edges of the discharge orifice and of the base of the pintle valve head must be free of burrs and other imperfections, otherwise, the quality of the spray is not as good as desired. Likewise, the axes of the discharge orifice and of the conical head of the pintle valve must be truly coincident, or very nearly so, in order to obtain the proper quality of spray necessary for efficient combustion of the fuel in the engine. The presence of burrs, imperfections, eccentricities, etc., are all the more critical in known nozzles at low fuel fiows when the pintle valve has only moved a very small distance away from its position of engagement with the edge of the discharge orifice.

With the foregoing in mind, it is a principal object of this invention to provide a nozzle which produces a better quality spray throughout the entire fuel flow range thereof than is obtainable with known forms of nozzles. V

It is another object of this invention to provide an improved nozzle construction, the superior performance of which is hardly affected by the presence of slight burrs, imperfections, and eccentricities of the discharge orifice and pintle valve head.

It is another object of this invention to provide a nozzle in which the fuel is discharged therefrom through a variable area orifice that is composed of parallel plane annular faces of the nozzle body and pintle valve respectively, and in which the resulting plane circular sheet of fuel is converted into a spray cone of fine droplets by impingement of the fuel on the internal face of a deflector that surrounds said variable area orifice.

It is another object of this invention to provide a nozzle having a conical deflector against which the stream of fluid issuing from the nozzle impinges to break up the stream into fine droplets and to control the spray cone angle.

It is another object of this invention to provide a nozzle having a double-angled conical deflector for increased efficiency in break-up of the fluid impinging thereon into finely divided particles and for accurate control of the spray cone angle.

Other objects and advantages of the present invention will become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail certain illustrative embodiice ments of the invention, these being indicative, however, of a few of the various ways in which the principle of the invention may be employed.

In said annexed drawings:

lFIG. 1 is a central longitudinal cross-section view through one form of nozzle embodying the present invention;

FIG. 2 is an enlarged fragmentary cross-section view of the FIG. 1 nozzle showing the pintle valve thereof in open condition permitting discharge of fuel for producing the desired fine quality of spray of the fuel;

FIG. 3 is a fragmentary cross-section view illustrating another form of nozzle embodying the present invention;

FIG. 4 is a cross-section view of yet another form of nozzle embodying the present invention;

FIG. 5 is an end elevation view of the FIG. 4 nozzle as viewed from the right-hand end of FIG. 4;

FIG. 6 is a central longitudinal cross-section view illustrating yet another form of nozzle embodying the present invention; and

FIG. 7 is a much enlarged fragmentary cross-section view showing how the stream of fuel emerges radially from between the seats of the pintle valve and the nozzle body and impinges against the internal tapered walls of the surrounding deflector to produce the desired spray cone.

Referring now more particularly to the drawings, and first to FIG. 1, the nozzle 1 there shown comprises a nozzle body 2 having an orifice bushing 3 mounted therein at its forward end. Rearwardly adjacent the orifice bushing 3 said body 2 has mounted therein a guide 4 for the pintle valve 5. The portion of the valve 5 guided in the bore of guide 4 has longitudinal slots which permit equalization of pressures on both sides of the lands between such slots. The orifice bushing 3 may be made as of tungsten carbide or equivalent hard, wear-resisting material, and is brazed or otherwise secured in the nozzle body 2.

The pintle valve 5 has a knurled or serrated cylindrical head 6 on which is secured as by brazing a tungsten carbide or equivalent bushing 7. Adjacent said pintle valve head 6 there is provided a neck portion 8 that defines with the orifice bushing 3 an annular passage 9. The juxtaposed ends of bushings 3 and 7 are formed with plane annular seats '10 and '11.

The rear end of the pintle valve 5 is threaded as shown and has axially adjustably mounted thereon a spring follower and guide 12 for the spring 14 which is adjustably compressed between said follower 12 and the nozzle body 2 by turning the pintle valve 5 with respect to the follower 12. A nut 15 on the threaded end of the pintle valve bears on follower 12 to lock the pintle valve 5 and follower 12 in adjusted position predeterminedly compressing spring 14. Preferably, the spring 14 is fabricated from a length of round tubular stock which has sets of uniformly circumferentially offset transverse slots 16 arranged to eliminate tendency of canting of the ends with respect to each other and with respect to the pintle valve axis and also to provide a relatively rigid lateral support for the rear end of the pintle valve 5 in conjunction with the guide 4 in coaxial position with respect to the orifice bushing 3.

It can be seen that when the fuel pressure acting on the area A of the pintle valve 5 exceeds the preload of spring 14, the pintle valve will be moved forwardly in body 2, thereby moving seat 11 away from seat 10 to permit discharge of fuel radially outward between said seats. As the fuel pressure increases the gap between seats 10 and 11 will progressively increase to permit'increased flow of fuel from the nozzle.

' It is to be noted that the orifice and pintle valve bushings 3 and 7 are coaxial and of the same inside and outside diameters, that the orifice bushing 3 projects axially beyond the surrounding deflector 17 of the nozzle 1, and that the pintle valve bushing projects rearwardly of the head 6. Accordingly, the annular plane ends or seats 10 and 11 of said bushings 3 and 7 respectively, are of equal radial extent and in register.

As aforesaid, there is provided around the orifice and pintle valve bushings 3 and 7 a deflector '17 which, as shown in FIG. 1, is shaped internally to provide a double-angled conical surface 1819 of which both angles are preferably, but not necessarily, of apex angle greater than 90 but substantially less than 180. For good results, the interior conical surface 18-19 of the deflector 17 comprises adjacent coaxial cones 18-19 of different apex angles, with the larger apex angle of cone 18 being about to 15 (preferably greater than the desired spray cone angle, and with the smaller apex angle of cone v 19 being about 5 to (preferably 10) less than the desired spray cone angle. The axial position of the intersection of these cones 18 and 19 relative to seats 10 and 11 is not critical, but it is preferred that said line 20 be in the same plane as the pintle valve seat 11 when the pintle valve *5 is the fully open position of FIG. 2 as determined by the maximum fuel pressure available. The deflector 17 herein also is preferably made of relatively hard material such as tungsten carbide and is herein shown as being brazed to the nozzle body 2.

With a nozzle structure as hereinabove-described, and as best shown in FIG. 2, slight eccentricity of the pintle valve seat 11 with respect to the discharge orifice seat 10 is of no moment in respect of overall improved nozzle performance, nor are slight burrs or other imperfections in these seats or the edges thereof. When the nozzle 1 is in operation with the pintle valve 5 unseated as in FIG. 2, the fuel will flow radially outwardly through the circular gap between the plane annular seats 10 and 11, and will impinge, as shown, on the double-angled conical internal face 18-19 of the surrounding deflector 17 to break up the fuel into fine droplets having the desired spray cone angle which, as aforesaid, is in between the apex angles of the cones 18 and 19.

Surrounding the pintle valve biasing spring 14 in frictional contact therearound is the longitudinally split damping sleeve 21 which is effective to dampen vibrations or flutter of the pintle valve 5. Accordingly, turbulent flow of fuel between the seats 10 and 11 and fuel pressure pulsation and fluctuation will not cause fluttering or vibration of the pintle valve 5, the frictional drag of the damping sleeve 21 about the pintle valve spring being effective to absorb such movements of the pintle valve. Moreover, the seats 10 and 11 are thereby prevented from pounding against each other.

The nozzle 25 shown in FIG. 3 basically is of the same construction as that shown in FIGS. 1 and 2 except that the deflector 26 and orifice bushing 27 are formed as a single part, as of tungsten carbide or the like, adapted to be brazed or otherwise secured in the nozzle body 28. Here again, as in FIGS. 1 and 2, there is provided a double-angle conical surface 29-30 on the interior of the deflector 26 for the purposes described in relation to FIGS. 1 and 2.

The nozzle shown in FIGS. 4 and 5 also has all of the attributes of the FIGS. 1 and 3 nozzles. In FIGS. 4 and 5 the nozzle body 36 is itself made of hardened steel or the like, and is integrally formed with the discharge orifice 37 and the plane annular seat 38 for the pintle valve 39, the seat 38 again as in FIGS. 1 to 3, extending axially within a deflector ring 40 secured as by brazing to the nozzle body 36' and having a doubleangled conical deflecting surface 41-42 surrounding the cylindrical head 43 and plane annular seat 44 of the pintle valve 39. The pintle valve spring 45 is generally of the same form as the spring 14 employed in the FIG. 1 nozzle and bears at one end against the shoulder 46 of the body 36 and at the other end against the shoulder 47 of the spring follower 48, the degree of compression of the spring being changed by manipulating the nuts 49 and 50 that are screwed onto the rear threaded end of the pintle valve 39. The spring follower 48 herein is formed with a series of longitudinal grooves 51 forming fuel flow passages and, in addition, the spring follower 48 is formed with a longitudinal slot 52 radially through the wall thereof so that the surfaces of the ribs 53 between adjacent grooves 51 will frictionally engage the inside face of the pintle valve spring 45, such frictional engagement serving as a damping means to eliminate or minimize fluttering and vibration of the pintle valve 39. The stem portion 54 of the pintle valve 39 is preferably a close fit in the bore of the spring follower 48 so that the pintle valve seat 44- will be held coaxially relative to the plane annular seat 38 of the nozzle body 36.

By way of illustration, it has been found that nozzles according to the present invention having a rating of 1000 lbs/hr. fuel flow at 800 psi. fuel pressure and an opening pressure of 100 p.s.i. as set by the pintle valve springs provide good spray quality even at low fuel flows of 20 lbs/hr. In contradistinction, variable area nozzles of the same rating but employing conical bead pintle valves have much deteriorated spray quality at fuel flows from 50 lbs/hr. and less.

In the case of the nozzle shown in FIGS. 1 and 2, for example, wherein the discharge orifice in bushing 3 is of .088" diameter and the stem 8 of the pintle valve 5 is of .038" diameter, good results as aforesaid have been obtained by making the seats 10 and 11 of about .020" radial width. The conical surfaces 18 and 19 of about 128 and 102 apex angle respectively then should intersect as represented by the line 20 which is of about .11"

' diameter and which is substantially in the same plane as the seat 11 of the pintle valve 5 when the latter is in open position (about .012" gap between seats 10 and 11) under the influence of the maximum available fuel pressure.

With reference to the nozzle shown in FIG. 6, it is much like that shown in FIG. 1, except for two things, namely, upon removal of the hood from the nozzle body 61, the deflector 62 with its double-angle surfaces 63-64 may be readily assembled and disassembled by reason of the provision of the cap 65 which has threaded engagement, as shown with the nozzle body 61. As evident from the discussion of the other nozzles herein, they are all of very small size and, therefore, welding or brazing operations are quite fussy and may result in damage or distortion of the parts. The bore of the deflector 62 is preferably a close fit on the forwardly projecting end of the orifice bushing 67.

Another feature of the FIG. 6 nozzle is that the slotted portion of the pintle valve spring 68 is free to yield and will not be subject to erratic action owing to presence of foreign particles in the fuel. In other words, the yieldable portion of the spring 68 has no sliding fits with any of the nozzle parts.

Yet another feature of the FIG. 6 nozzle is that frictional damping of the movements of the pintle valve 69 is provided by adjustable binding action of the stem 70 thereof in the bore 71 of the guide 72. In the present case the spring follower 73 is formed with a transverse slot 74 and a setscrew 75, When turned, tends to spread apart the slot 74 and thereby cause bending of the stem 70 with resultant frictional drag in the guide bore 71 of the guide 72. In this way, there is provided controlled and adjustable damping of the movements of the pintle valve 69 with resulting elimination or minimization of vibration and flutter thereof. As in the other nozzles, the orifice bushing 67 and the pintle valve 69 have cooperating plane annular seats 76 and 77.

Finally, with reference to FIG. 7, it will be seen that when the pintle valve 5 (or pintle valve 39 or 69 in FIG.

4 or 6) is unseated as shown, the fuel will flow radially as a relativel thin sheet between the plane annular seats and 11, (or seats 38 and 44 in FIG. 4, or seats 76 and 77 in FIG. 6) and it is believed that by reason of the provision of the sharp inner edges 78 and 79 there will be a vena contracta 80 where the fuel first enters the orifice defined between the plane annular seats 10 and l l. The outer face 81 of the fuel sheet, in the rated flow position of the pintle valve 5, will coincide with the intersection 20 of the faces 18 and 19. The inner face 82 of the fuel sheet will impinge on surface 18 as shown and will be reflected thereby and will intersect like elements between faces 81 and 82. The resultants 83, in turn will impinge on face 19 and bounce therefrom as indicated by lines 84 to produce a spray cone of desired angle and of finely sub-divided fuel droplets for eflicient distribution and combustion in the combustion chamber.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims, or the equivalent of such, be employed.

We therefore particularly point out and distinctly claim as our invention:

1. A fuel injection nozzle comprising a body having an inlet for fuel under pressure and a discharge orifice, said orifice terminating in a plane annular seat; a springbiased, fuel pressure actuated pintle valve movable in said body and having a plane annular seat, said pintle valve being movable under the influence of progressively increasing fuel pressure in said inlet from a position whereat said seats are in engagement to a position whereat said seats are spaced apart a progressively increasing distance for discharge of fuel from between said seats; spring means between said body and valve biasing the latter as aforesaid; spring damping means in frictional contact with said spring means; and a deflector on said body disposed around said seats and against which the fuel emerging from between said seats impinges and thus is broken up into spray form.

2. A nozzle according to claim 1 wherein said spring means has a cylindrical surface and said spring damping surface is a cylindrical surface in frictional contact therewith.

3. A nozzle according to claim 1 wherein said spring means comprises a tubular portion having transverse slots providing axially adjacent pairs of diametrically opposed and circumferentially offset bridges; and, wherein said spring damping means comprises a sleeve surrounding said tubular portion in frictional contact therewith.

4. A nozzle according to claim 1 wherein said body has a guide therein in which the lands of a longitudinally slotted portion of said pintle valve is movable.

5. A fuel injection nozzle comprising a body having an inlet for fuel under pressure and a discharge orifice, a pintle valve movable in said body, spring means between said body and valve; and spring dam-ping means having a surface in frictional contact with said spring means.

6. A nozzle according to claim 5 wherein said spring means is cylindrical in shape and said damping means comprises a cylindrical surface in frictional contact therewith.

7. A nozzle according to claim 5 wherein said spring means comprises a tubular portion having transverse slots providing axially adjacent pairs of diametrically opposed and circumferentially offset bridges; and, wherein said spring damping means comprises a sleeve surrounding said tubular portion in frictional contact therewith.

References Cited in the file of this patent UNITED STATES PATENTS 1,893,457 Tartrais Jan. 3, 1933 2,145,429 Nelson Jan. 31, 1939 V FOREIGN PATENTS 248,119 Germany Mar. 3, 1911 628,922 France July 11, 1927

Claims (1)

1. 5. A FUEL INJECTION NOZZLE COMPRISING A BODY HAVING AN INLET FOR FUEL UNDER PRESSURE AND A DISCHARGE ORIFICE, A PINTLE VALVE MOVABLE IN SAID BODY, SPRING MEANS BETWEEN

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