US3540658A

US3540658A - Antierosion fuel injection nozzle

Info

Publication number: US3540658A
Application number: US709650A
Authority: US
Inventors: Harold C Simmons
Original assignee: Parker Hannifin Corp
Current assignee: Parker Hannifin Corp
Priority date: 1968-03-01
Filing date: 1968-03-01
Publication date: 1970-11-17
Anticipated expiration: 1987-11-17
Also published as: GB1195356A; DE1910293A1; BE729087A

Description

United States Patent [72] Inventor Harold C. Simmons Richmond Heights, Ohio 709,650

March 1, 1968 Nov. 1 7, i970 Parker-Hanniiin Corporation Cleveland, Ohio a corporation of Ohio [2!] Appl. No. [22] Filed [45] Patented [73] Assignee [54] ANTIEROSION FUEL INJECTION NOZZLE 5 Claims, 5 Drawing Figs. [52] US. Cl. 239/472, 239/492; 233/19 [51] int. Cl. B05b 1/34 [50] Field of Search 239/402,

[56] References Cited UNITED STATES PATENTS 3,131,3779 5/1964 Ro'wley et a]. 239/602X FOREIGN PATENTS 535,097 3/1941 Great Britain 239/468 Primary Examiner-M. Henson Wood, Jr. Assistant Examiner-Michael Y. Mar Attorney Oberlin, Maky, Donnelly and Renner ABSTRACT: Fuel injection nozzle of the type wherein a hollow conical spray of finely atomized liquid is produced by the action of a vortex within the nozzle. Nozzle characterized in that upstream portion of vortex chamber is diametrically enlarged adjacent the spin slots through which the liquid is tangentially introduced into the vortex chamber, the thus enlarged portion of the vortex chamber preferably being made of hard, erosion-resistant material.

Patented Nov. 17, 1970 3,540,658

l3 7 m l3 |4 2:2 AVID C24 i H 26 Q m F INVENTOR 5.19. .E 25 HAROLD c. SIMMONS BY fiMqMflamwZQ/QKW ATTORNEYS 1 ANTIEROSION FUEL INJECTION NOZZLE BACKGROUND OF THE INVENTION Typically, a fuel injection nozzle of the type with which this invention is concerned comprises a nozzle tip assembly having a discharge orifice and an adjacent coaxial vortex chamber which usually is of three or more times larger in diameter than the discharge orifice, the liquid fuel being forced under pressure into said vortex chamber through tangential inlet holes or slots to impart to the fuel a spinning or vortex action. The fuel is thus discharged from the discharge orifice in the form of a hollow conical spray, and as known in the art, high velocities and high rotational speeds of the fuel are necessary in order to produce a finely atomized fuel for burning in gas turbines and the like.

In practice, although the fuel systems contain filters, it has been found virtually impossible to completely filter all particles of solid matter therefrom. The presence of contaminants in the fuel may be due to inadequate cleaning or filtration of the raw materials from which it is produced, to ingress of airborne dust and dirt through the vents of storage vessels, to chemical changes in the fuel itself, and/or to release of foreign substances from liquid pumping and control systems.

In any event, regardless of the source of the contaminants, it has been found that the peripheral wall of the spin chamber of a nozzle is especially subject to erosion by such contaminants. The contaminants tend to be retained or trapped in the spin chamber at the maximum diameter thereof adjacent the fuel inlet holes. For example, in a particular nozzle where the diameter of the spin chamber is equal to 0.125 inch, where the diameter of each of two inlet holes is 0.018 inch, where the nozzle inlet pressure is 300 p.s.i., where the fuel density is 50 lbs./ft. and where the viscosity is 1.5 centistokcs, spherical particles of about three times the density of the fuel will be retained by centrifugal action when the particles are greater than 12 microns in diameter. Under these conditions the centrifugal acceleration is about 35000 g and the velocity of the liquid in the periphery of the spin chamber is about 75 ft./sec. The quantity of trapped contaminant can increase to significant value and can erode the material of the nozzle tip by a scrubbing action against the wall of the spin chamber. Once the process of erosion has commenced, the pattern of liquid flow within the spin chamber is affected and eddy currents occur which tend to increase the rate of erosion in local areas. The erosion effect is not limited to removal of nozzle material, but in some cases causes plastic flow of the material adjacent the exit edges of the inlet holes. Such erosion has occurred to such extent as to affect nozzle performance with resulting change in flow calibration and deterioration of spray quality.

SUMMARY OF THE INVENTION It is a principal object of this invention to provide a fuel injection nozzle .having a spin chamber which has an internal diametrically enlarged groove which forms a contaminanttrapping groove of larger diameter than the portion of the spin chamber with which the inlet holes communicate.

It is a further object of this invention to provide a fuel injection nozzle having the geometry aforesaid and in which at least the enlarged portion of the spin chamber is of erosion-resistant material.

It is a further object of this invention to provide a fuel injection nozzle as aforesaid, wherein the remaining portions of the spin chamber adjacent the grooved portion thereof which is of erosion-resistant material may be made of conventional readily machinable materials such as are presently used in nozzle construction.

It is a still further object of this invention to provide a fuel injection nozzle which has not only the enlarged portion of the spin chamber formed of erosion-resistant material, but also the remaining portions of the spin chamber including the discharge portion, to minimize wear and erosion in the discharge orifice.

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 embodiments of the invention, these being indicative, however, of a few of the various ways in which the principle of the invention may be employed.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a partial cross section view of a fuel injection nozzle embodying the present invention;

FIG. 2 is a cross section view taken substantially along the line 2-2, FIG. 1; and

FIGS. 3, 4,,and 5 are fragmentary cross section views illustrating three further embodiments of this invention.

DESCRIPTION-OF THE PREFERRED EMBODIMENTS 0 Referring to FIGS. 1 and 2, the fuel injection nozzle 1 shown therein comprises a nozzle body or connector 2 which has a threaded connection with a nozzle mount 3 of a spray bar 4, a lock ring 5 being interposed between the mount 3 and the connector 2. The connector 2 has a fuel passage6 which, through the nozzle mount 3, communicates with a fuel supply passage in the spray bar 4.

Screwed onto the connector 2 is a nozzle cap 7 between which and the end of the connector 2, is clamped a ring 8 which is formed with an internal groove or undercut 9 of larger diameter than the maximum diameter D of the vortex chamber 10 which is defined between the end of the connector and the conical bore 11 of the nozzle cap 7. The ring 8 aforesaid is fabricated of erosion-resistant material such as tungsten carbide or chromium carbide for a purpose which hereinafter is described in further detail.

The fuel which enters the inlet passage 6 flows through the cross bore 12 in the connector 2 into the annular space 13 defined between the nozzle cap 7 and said connector 2 and thence flows into the spin chamber 10 through a pair of tangentially disposed inlet holes 14 thus to cause the incoming fuel to have a whirling or spinning velocity imparted thereto. As the spinning fuel flows axially toward the discharge orifice, it will pass the groove 9 in the ring 8, whereby solid contaminant particles in the fuel will be centrifuged into the groove 9 and not allowed to remain in contact with other portions of the spin chamber 10. The hollow liquid sheet with contaminants left behind in the contaminant-trapping groove 9 then flows along the conical approach 11 to the discharge orifice 15 at increasing spin velocity so that when discharged through the orifice 15 the liquid sheet will be broken up into finely divided particles to provide a hollow spray cone. Because the ring 8 is madeof erosion-resistant material, erosion due to centrifuging of contaminants in the groove 9 is minimized.

In the embodiment of the invention illustrated in FIG. 3, the contaminant-trapping groove 16 is defined by a pair of rings 17 made of erosion-resistant material. Because the contaminant-trapping groove 16 is made in two parts, machining'or forming thereof is facilitated.

FIG. 4 illustrates a fuel injection nozzle similar to FIG. 3 except that the nozzle cap 18 has been modified to accommodate two

rings

19 and 20 which define the contaminanttrapping groove 21, ring 20 also being integrally formed with the conical approach 22 and discharge orifice 23. Both

rings

19 and 20 are made of erosion-resistant material to minimize erosion not only in the groove 21 but in the conical approach 22 and in the orifice 23.

In the embodiment of the invention illustrated in FIG. 5, the connector 24 which has the tangential inlet holes 14 is also provided with the contaminant-trapping groove 25, the connector 24 being made of conventional nozzle material. To render the contaminant-trapping groove 25 erosion resistant it is provided with a surface coating 26 of hard material which may, for example, be flame-sprayed tungsten carbide.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described.

I claim:

1. In a spray nozzle of the type having a spin chamber into which liquid is introduced through a tangential inlet opening to impart a spinning motion to the liquid and from which liquid is discharged through an orifice in the form of a hollow conical spray, the improvement which comprises the provision of a radially inwardly open annular groove in the wall of said spin chamber between said orifice and said inlet opening into which groove contaminants in the liquid are centrifuged to become trapped therein, said nozzle comprising a nozzle body, a nozzle cap, and a ring of erosion-resistant material between said cap and body and having such contaminanttrapping groove therein.

2. The nozzle of claim 1 wherein said ring comprises a pair of rings of erosion-resistant material defining therebetween such contaminant-trapping groove.

3. The nozzle of claim 2 wherein one of said rings contains said orifice and a portion of said spin chamber between said orifice and said groove.

4. The nozzle of claim 1 wherein said ring is integral with said body, at least the surface of such groove being of erosion resistant material.

5. The nozzle of claim 4 wherein the erosion resistant material is in the form of a flamesprayed coating applied at least on the surface of such groove.