BRIEF DESCRIPTION OF THE DRAWINGS
So that those skilled in the art to which the subject invention appertains will readily understand how to make and use the fuel injectors of the subject invention without undue experimentation, preferred embodiments thereof will be described in detail hereinbelow with reference to certain figures, wherein:
FIG. 1 is a side elevational view, in cross-section, of a prior art fuel injector having an injector body with a longitudinal bore supporting a fuel delivery tube, wherein the fuel delivery tube has an inlet end joined to a fitting at an inlet end of the injector body and an outlet end joined to an atomizer at an outlet end of the injector body;
FIG. 2 is a side elevational view, in cross-section, of a fuel injector constructed in accordance with a preferred embodiment of the subject invention, wherein a corrugated metallic diaphragm is joined to an inlet end portion of the fuel delivery tube and to an interior wall of the longitudinal bore formed in the injector body;
FIG. 3 is an enlarged side elevational view, in cross-section, of the inlet end of the fuel injector of FIG. 2, illustrating the shape of the corrugated flexible metallic diaphragm when the injector body undergoes thermal expansion relative to the fuel delivery tube during engine operation;
FIG. 4 is an enlarged perspective view, in cross-section, of the corrugated metallic diaphragm shown in FIGS. 2 and 3, illustrating the concentric corrugations thereof;
FIG. 5 is an enlarged side elevational view, in cross-section, of an inlet end of another fuel injector constructed in accordance with a preferred embodiment of the subject invention, wherein two conjoined corrugated flexible metallic diaphragms are associated with an inlet end portion of the fuel delivery tube;
FIG. 6 is an enlarged side elevational view, in cross-section, of an inlet end of still another fuel injector constructed in accordance with a preferred embodiment of the subject invention, wherein a flat flexible metallic diaphragm is joined to an inlet end portion of the fuel delivery tube and to an interior wall of the longitudinal bore formed in the injector body;
FIG. 7 is an enlarged side elevational view, in cross-section, of the inlet end of the fuel injector of FIG. 6, illustrating the shape of the flat flexible metallic diaphragm when the injector body undergoes thermal expansion relative to the fuel tube during engine operation; and
FIG. 8 is an enlarged side elevational view, in cross-section, of an inlet end of yet another fuel injector constructed in accordance with a preferred embodiment of the subject invention, wherein a generally C-shaped flexible metallic channel is associated with an inlet end portion of the fuel tube.
ENABLING DESCRIPTION OF PREFERRED EMBODIMENTS
Referring now to the drawings, there is illustrated in FIG. 1 a prior art fuel injector 10 for a gas turbine engine. Fuel injector 10 has an injector body 12 with a longitudinal bore 14 extending therethrough supporting a fuel delivery tube 16. The fuel delivery tube 16 has an inlet end fixedly joined by way of brazing or welding to a fitting 18 at an inlet end of the injector body 12 and an outlet end fixedly joined by way of brazing or welding to an atomizer nozzle 20 at an outlet end of the injector body 12.
The injector body 12 includes a support flange 22 for mounting the injector 10 to the outer casing of a gas turbine engine combustor (not shown). Once mounted, the fitting 18 is located exterior to the outer casing and the atomizer support body 12 is located on the interior of the engine casing, with the atomizer nozzle 20 issuing atomized fuel into the combustor of a gas turbine engine. During engine operation, the injector support body 12 is surrounded by high temperature compressor air flowing through the engine casing, while the fuel delivery tube 16 located within the injector support body 12 is maintained at a relatively lower temperature, because it carries lower temperature fuel to the atomizer nozzle 20. Consequently, injector support 12 undergoes thermal expansion differently than the fuel delivery tube 16.
Referring now to FIG. 2, there is illustrated a fuel injector constructed in accordance with a preferred embodiment of the subject invention and designated generally by reference numeral 100. Fuel injector 100 includes a corrugated flexible metallic diaphragm 130 that is joined to the inlet end portion of the fuel delivery tube 116 and to an interior wall of the longitudinal bore 114 formed in the injector body 112. The outlet end portion of fuel delivery tube 116 is brazed or otherwise rigidly connected to the atomizer nozzle 120.
As best seen in FIG. 3, during engine operation, when the injector body 112 is surrounded by high temperature compressor air and the fuel tube 116 carries lower temperature fuel, the corrugated flexible metallic diaphragm 130 compensates for the thermal expansion of the injector support body 112 relative to the fuel delivery tube 116 by expanding downwardly. The depicted expanded configuration of diaphragm 130 and the extent to which the diaphragm is shown to expand are merely illustrative of the concepts embodied herein, and should not be construed in any way to limit the scope of the subject invention.
As illustrated in FIG. 4, the corrugated metallic diaphragm 130 is generally circular in configuration with a plurality of concentric corrugations 132. A mounting aperture 134 is provided at the center of diaphragm 130 for receiving the inlet end portion of fuel delivery tube 116. Diaphragm 130 also has an outer peripheral edge 136 to facilitate a rigid connection between the diaphragm and the interior wall of bore 114. More particularly, diaphragm 130 is accommodated within an enlarged cavity 114a of longitudinal bore 114, which is located at the inlet end of injector body 112 proximate inlet fitting 118. Although the diaphragm 130 is illustrated and described as having a generally circular configuration, those skilled in the art will readily appreciate that the shape of the diaphragm can and will vary depending upon the cross-sectional shape of the cavity or bore within which the diaphragm is mounted. Furthermore, the number and geometry of the corrugations can vary to achieve a particular degree of flexibility.
Referring to FIG. 5, in another embodiment of the fuel injector 100, a dual diaphragm structure 140 is operatively associated with the inlet end portion of fuel delivery tube 116. Dual diaphragm 140 is preferably formed from two conjoined corrugated flexible metallic diaphragms, including an upper diaphragm 142a and a lower diaphragm 142b. The upper diaphragm 142a is brazed or otherwise rigidly connected to an inlet section 116a of fuel delivery tube 116, while the lower diaphragm 142b is brazed or otherwise rigidly connected to the main section of fuel delivery tube 116. In this embodiment of the invention, the inlet end section 116a of fuel delivery tube 116 is in turn brazed or otherwise rigidly connected to the fuel passage of inlet fitting 118. Here, there is no rigid connection between the dual diaphragm 140 and the interior wall of the enlarged cavity 114a of longitudinal bore 114. Those skilled in the art will readily appreciate that the dual diaphragm 140 could be formed as a one-piece, unitary structure, rather than from two conjoined diaphragms, as described above.
Referring now to FIGS. 6 and 7, in another embodiment of fuel injector 100, a flat flexible metallic diaphragm 150 is joined to an inlet end portion of the fuel delivery tube 116 and to an interior wall of the longitudinal bore 114 formed in the injector body 112. More particularly, a mounting aperture 152 is provided at the center of diaphragm 150 for receiving the inlet end portion of fuel delivery tube 116, and diaphragm 150 has an outer peripheral edge 154 to facilitate a rigid connection between the diaphragm 150 and the interior wall of bore 114a. When the engine employing nozzle 100 is not in operation, the flat flexible metallic diaphragm 150 is preferably disposed in a pre-stressed or pre-loaded state, which is shown for example in FIG. 6. To compensate for the thermal expansion of the injector support body 112 relative to the fuel delivery tube 116 during engine operation, the flat pre-loaded diaphragm moves to an expanded state, shown for example in FIG. 7. The depicted pre-stressed and expanded configurations of diaphragm 150 and the extent to which diaphragm 150 is shown to expand are merely illustrative of the concepts embodied herein, and should not be construed in any way to limit the scope of the subject invention.
Referring now to FIG. 8, in yet another embodiment of the subject invention, a bent or generally C-shaped flexible metallic channel structure 160 is associated with an inlet end portion of fuel tube 116a to compensate for the thermal expansion of the injector support body 112 relative to the fuel delivery tube 116 during engine operation. Channel structure 160 has an internal fuel path communicating with fuel delivery tube 116, and it includes a straight upper leg portion 162a, a straight lower leg portion 162b and a curved connective portion 162c between the upper and lower leg portions 162a, 162b. The upper leg portion 162a is brazed or otherwise rigidly connected to an inlet section 116a of fuel delivery tube 116, while the lower leg portion 162b is brazed or otherwise rigidly connected to the main section of fuel delivery tube 116. In this embodiment of the invention, the inlet end section 116a of fuel delivery tube 116 is in turn brazed or otherwise rigidly connected to the fuel passage of inlet fitting 118. Here, there is no rigid connection between the channel structure 160 and the interior wall of the enlarged cavity 114a of the longitudinal bore 114 of injector 100.
It is envisioned and well within the scope of the subject disclosure that the concepts and embodiments described herein could be employed in a two-stage or dual-fuel injector that has two concentric fuel delivery tubes extending through a bore in an injector support body. In a two-stage fuel injector, for example, a primary inner fuel tube delivers fuel to a pilot atomizer of the injector nozzle and a secondary outer fuel tube delivers fuel to a radially outer main atomizer of the injector nozzle. It is envisioned that the inlet end portion of the outer fuel tube would have a first flexible metallic diaphragm associated therewith and the inlet end portion of the inner fuel tube would extend beyond the inlet end portion of the outer fuel tube and have a second flexible metallic diaphragm associated therewith. The two diaphragms would be axially spaced apart from one another and rigidly connected to the interior wall of the longitudinal bore of the injector body at axially spaced apart locations.
While the apparatus and method of subject invention have been shown and described with reference to preferred embodiments, those skilled in the art will readily appreciate that changes and/or modifications may be made thereto without departing from the spirit and cope of the subject invention.
Patent Application
20070283931
