Patent Application
20160003479
The present invention is directed to processes of assembling fuel nozzle components having fuel nozzles. Most specifically, the present invention is directed to processes of assembling fuel nozzle end covers.
In general, gas turbines are being subjected to more demanding operation. Higher temperatures, harsher environments, use in more diverse environments, and extended duration of use result in challenges for gas turbines and their components. Extending the useful life of such components and improving capability for repair of such components can decrease costs associated with the gas turbines and can increase the operational aspects of the gas turbines.
Known end covers on fuel nozzles in gas turbines have an insert brazed into the end cover. Generally, such inserts have four braze joints securing the inserts within the end cover. These braze joints are subject to failure, for example, resulting in leaking proximal to the braze joints. Such braze joints can also suffer from a drawback of requiring frequent repair. Such repairs can be complex and expensive. In addition, the ability to perform such repairs may be limited.
A process of assembling a fuel nozzle end cover that shows improvements over the prior art would be desirable in the art.
In an embodiment, a process of assembling a fuel nozzle end cover includes machining a base material of the fuel nozzle end cover to define a cylindrical region, the cylindrical region including ports for fluid transport within the fuel nozzle end cover, then positioning a ring insert in contact with the base material within the cylindrical region in a position that permits the fluid transport through the ports, then welding the ring insert to the base material to define one or more ledge features within the fuel nozzle end cover in the position that permits the fluid transport through the ports. The ring insert has a net shape or near-net shape.
In another embodiment, a process of assembling a fuel nozzle end cover includes machining a body to form a ring insert and machining a base material of the fuel nozzle end cover, then positioning the ring insert in contact with the base material, then welding the ring insert to the base material to define one or more ledge features within the fuel nozzle end cover. The ring insert has a net shape or near-net shape.
In another embodiment, a process of assembling a fuel nozzle end cover includes machining a base material of the fuel nozzle end cover, then positioning a first ring insert in contact with the base material, then welding the first ring insert to the base material, then positioning a second ring insert in contact with the base material, then welding the second ring insert to the base material. The first ring insert and the second ring insert have net shapes or near-net shapes.
Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.
Wherever possible, the same reference numbers will be used throughout the drawings to represent the same parts.
Provided are processes of assembling a fuel nozzle end cover, for example, for a fuel nozzle in a turbine system. Embodiments of the present disclosure, in comparison to similar concepts failing to include one or more of the features disclosed herein, permit better sealing within fuel nozzle end covers, permit increased operational efficiency of turbine systems using fuel nozzles, reduce or eliminate weld spatter within fuel nozzle end covers, overcome challenges presented by brazing within fuel nozzle end covers, permit use of fuel nozzle end covers with otherwise incompatible fuel nozzle inserts, or a combination thereof.
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In one embodiment, at least one of the ring inserts 300 has a stepped geometry. In a further embodiment, at least one of the ring inserts 300 includes a first surface 203 to be positioned to abut the base material 106 when secured, a second surface 204 extending in a direction substantially perpendicular to the first surface 203 (for example, to be positioned to extend into the cavity 110), a third surface 206 extending in a direction substantially perpendicular to the second surface 204 (for example, to be positioned parallel to the first surface 203), a fourth surface 208 extending in a direction substantially perpendicular to the third surface 206 (for example, to be positioned to extend into the cavity 110), a fifth surface 210 extending in a direction substantially perpendicular to the fourth surface 208 (for example, to be positioned parallel to the first surface 203), and a sixth surface 212 extending in a direction substantially perpendicular to the fifth surface 210 when secured (for example, to be positioned in a direction extending toward the base material 106). In one embodiment, at least one of the ring inserts 300 includes a geometry that is not stepped, for example, having at least one of the ledge features 108 with a sloping portion 220 (see
According to the present disclosure, the ring inserts 300 are secured to the base material 106 by welding. The securing of the ring inserts 300 to the base material 106 results in a predetermined microstructure (not shown) based upon the welding process utilized. The welding permits repeated insertion and removal of the insert 102 into the fuel nozzle end cover 104. For example, in one embodiment, the insert 102 is capable of being removed from the fuel nozzle end cover 104 with little or no damage to the fuel nozzle assembly 100 at least a predetermined number of times, for example, more than three times, more than four times, more than five times, or more than ten times. The welding is by gas tungsten arc welding, gas metal arc welding, cold metal transfer, and combinations thereof and/or by beam welding, friction welding, and combinations thereof. As will be appreciated by those skilled in the art, other embodiments include characteristics distinguishing from techniques using brazing.
The ring insert(s) 300 is/are welded to permit fluid transport within the fuel nozzle end cover 104 through feed holes or ports 101 positioned within the fuel nozzle assembly 100 (see
The material within the ring inserts 300 and the base material 106 are the same materials, substantially the same materials, or different materials. Such materials include any suitable metal or metallic composition (for example, stainless steel or stainless steel variations). In one embodiment, the ring inserts 300 and/or the base material 106 include austenitic stainless steel. In another embodiment, the ring inserts 300 and/or the base material 106 include ferritic stainless steel. In another embodiment, the ring inserts 300 and/or the base material 106 include martensitic stainless steel. In further embodiments, the ring inserts 300 include austenitic stainless steel, ferritic stainless steel, or martensitic stainless steel and the base material 106 includes a different stainless steel selected from the group of austenitic stainless steel, ferritic stainless steel, and martensitic stainless steel. In one embodiment, the material of the ring inserts 300 includes an equal or greater ductility in comparison to materials used for brazing and/or than the base material 106 would have when secured by welding, such as, beam welding (such as laser and/or electron beam), friction welding, (such as tungsten inert gas welding), and/or gas metal arc welding (such as metal inert gas welding).
While the invention has been described with reference to one or more embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. In addition, all numerical values identified in the detailed description shall be interpreted as though the precise and approximate values are both expressly identified.
