Patent Publication Number: US-8967206-B2

Title: Flexible fluid conduit

Description:
FIELD OF THE INVENTION 
     The invention relates to generally to fluid delivery systems, and more specifically, to a flexible fuel delivery conduit for use in gas turbine applications. 
     BACKGROUND OF THE INVENTION 
     In a gas turbine engine, fuel burns within the combustor to generate heat so as to provide energy to the turbine section of the engine. The generated heat being very intense, some of it tends to spread to parts surrounding the combustor, such as the fuel nozzles and its fuel supply conduit. Typically one or more fuel nozzles are provided around the combustor to supply fuel. Oftentimes, fuel flowing from fuel supply tubes in the fuel delivery conduit to the fuel nozzles will heat and each separate component of the conduit may expand at different rates due to the various coefficients of thermal expansion for each conduit component. This expansion of the fuel delivery conduit often causes stress on the fuel supply components of the conduit assembly. 
     It would be beneficial therefore to provide a fuel delivery component which conforms to a fuel conduit which fuel delivery component is configured to expand along an axis of thermal expansion growth of the fuel conduit component while maintaining its structural integrity. 
     SUMMARY OF THE INVENTION 
     In one aspect, a process for producing a fluid conduit is described in which an aspect of the invention includes forming at least one fluid delivery channel along the outer surface of a first elongate tubular body member. The first elongate tubular body member defining a longitudinal axis and an outer curved surface having a radius of curvature. A second elongate tubular body having an inner circumference is fitted about the outer circumference of the first tubular body so as to seal the at least one fluid delivery path channel on the outer surface of the first tubular body. A section of the fitted first and second tubular assembly is removed therefrom so as to define at least one fluid delivery path in the form of a sealed fluid conduit. 
     In further aspects, the foregoing product by process can include the steps of defining a plurality of fluid delivery channels along the outer surface of a first elongate tubular body member wherein each fluid delivery channel has at least one curved section defined by a first portion parallel to the longitudinal axis of the first tubular body, a second portion not parallel to the longitudinal axis of the first tubular body, and a third curved portion defined between the first and second portions and wherein each of the fluid delivery channels is formed so as to be nested relative to one another on the first tubular body. A second elongate tubular body having an inner circumference is sealed about the outer circumference of the first tubular body so as to seal each fluid delivery path channel defined along the outer surface of the first tubular body. A plurality of sections from the fitted first and second tubular bodies are removed wherein each removed section corresponds to a respective fluid delivery channel so as to define a plurality of expandable fluid conduits which may be affixed for use in nested relationship to one another. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The objects and features of the invention can be understood with reference to the following detailed description of an illustrative embodiment of the present invention taken together in conjunction with the accompanying drawings in which: 
         FIG. 1  is a perspective view of a first inner tubular body member used in accordance with an illustrated embodiment of the invention; 
         FIG. 2  is a perspective view of a second outer tubular body member used in accordance with an illustrated embodiment of the invention; 
         FIG. 3A  is a perspective view of the first inner tubular body member of  FIG. 1  having a channel formed along its outer surface; 
         FIGS. 3B-3D  are cross-sectional views of the first inner tubular body member of  FIG. 3A  depicting illustrative cross-sectional profiles of the fluid channel formed in the first inner tubular body member of  FIG. 3A ; 
         FIG. 4  is a perspective view of a first inner tubular body member of  FIG. 1  having multiple nested channels formed along its outer surface; 
         FIG. 5  is a perspective view of a first inner tubular body member of  FIG. 3  plated with a brazing alloy; 
         FIG. 6  is a perspective view of a first inner tubular body member of  FIG. 5  brazed and fitted to the second outer tubular member of  FIG. 2 ; 
         FIG. 7  is a perspective view of a fluid conduit removed from the assembly of the brazed and fitted first and second tubular body members of  FIG. 6 ; and 
         FIG. 8  is a perspective view of an environment of use for the fluid conduit of  FIG. 7 . 
     
    
    
     WRITTEN DESCRIPTION OF CERTAIN EMBODIMENTS OF THE INVENTION 
     The present invention is now described more fully with reference to the accompanying drawings, in which illustrated embodiments of the present invention are shown. The present invention is not limited in any way to the illustrated embodiments as the illustrated embodiments described below are merely exemplary of the invention, which can be embodied in various forms, as appreciated by one skilled in the art. Therefore, it is to be understood that any details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative for teaching one skilled in the art to variously employ the present invention. Furthermore, the terms and phrases used herein are not intended to be limiting but rather to provide an understandable description of the invention. 
     It is to be appreciated what is to be described below is a fluid conduit configured to be expandable along multiple axis&#39;. The fluid conduit may be used in a host of applications suitable for use with such an expandable fluid conduit. In accordance with an illustrated embodiment, the present invention, for descriptive purposes, is described in conjunction with a fuel delivery conduit preferably configured for use in gas turbine applications such as a liquid delivery manifold or supply tube designed for a high temperature environment where components of the gas turbine heat and expand at different rates. A noted advantage of providing an expandable liquid delivery manifold or supply tube is it permits fuel to be delivered between components operating under a high temperature by allowing for thermal expansion of the liquid delivery manifold or supply tube which mitigates the stress placed upon such a liquid delivery manifold or supply tube created by high temperatures. 
     As will be depicted in accordance with illustrated embodiments, the present invention provides a fuel tube that curves in multiple dimensions enabling it to confirm around a particular configured fuel component while permitting the fuel tube to expand along an axis of growth for a particular configured fuel component while maintaining its structural integrity. Therefore, what is to be appreciated and understood from the below description is a fuel delivery component (e.g. fuel tube, liquid delivery manifold, supply tube and the like) having a resultant geometry providing an enhanced reliable end position and stress profile relative to conventional mechanically bent fuel tubes. It is to be appreciated the below described fluid conduit, in accordance with the illustrative embodiments, is not to be understood to be restricted to a conduit for use with delivery of fluids, but may likewise be also used in conjunction with delivery of gaseous matter. 
     Optional embodiments of the present invention may also be said to broadly consist in the parts, elements and features referred to or indicated herein, individually or collectively, in any or all combinations of two or more of the parts, elements or features, and wherein specific integers are mentioned herein which have known equivalents in the art to which the invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth. 
     Starting with reference to  FIG. 1 , in accordance with the below illustrated embodiments, the process by which a present invention fluid conduit is produced will now be described. As shown, a first inner tubular body member, designated generally by reference numeral  10 , is provided, which as to be described below, is used to form a fluid conduit. First inner tubular body member  10  preferably has a cylindrical configuration having a circular cross-section as shown, but is not to be understood to be limited thereto as it may have any cylindrical configurations (e.g., elliptical) or other configurations (e.g., a squared shape cross-sectional body tubular body member) required for a particular application. First inner tubular body member  10  defines a longitudinal axis (as designated by arrow “A”) and is defined by outer  12  and inner  14  cylindrical surfaces. First inner tubular body member  10  may be fabricated from any material suitable for a particular fluid conduit application. For instance, when a produced fluid conduit is used as a fuel delivery conduit configured for use in gas turbine applications such as a liquid delivery manifold or supply tube designed for a high temperature environment where components of the gas turbine heat and expand at different rates, the first inner tubular body member  10  is preferably fabricated from a nickel-based temperature alloy such as Inconel® or a highly corrosion or oxidation resistant stainless steel. 
     With reference now to  FIG. 2 , a second outer tubular body member, designated generally by reference numeral  20  is provided, which as described below is used to provide a top seal for each fluid conduit formed in the first inner tubular member  10 . Second outer tubular body member  20  preferably has a cylindrical configuration which confirms to that of the first tubular body member  10  also defined by an outer  22  and inner  24  cylindrical surface wherein in an exemplary illustrated embodiment of the invention the diameter of its inner cylindrical surface  24  is preferably slightly greater than the diameter of the outer cylindrical surface  12  of the first tubular member  10  such that the second outer tubular member  20  is fitted about the first inner tubular member  10 , as described below. It is to be understood, in another embodiment of the invention, the diameter of inner cylindrical surface  24  of the second tubular member  20  is preferably slightly less than the diameter of the outer cylindrical surface  12  of the first tubular member  10  such that the second outer tubular member  20  is fitted about the first inner tubular member  10  by a heat/freeze shrink process so as to fit the second outer tubular member  20  about the first inner tubular member  10  via an interference fit. 
     Like the first inner tubular body member  10 , it is to be understood and appreciated the second outer tubular member  20  may be fabricated from any material suitable for a particular fluid conduit application. For instance, a fluid conduit may be used as a fuel delivery conduit configured for use in gas turbine applications such as a liquid delivery manifold or supply tube designed for a high temperature environment where components of the gas turbine heat and expand at different rates. 
     With reference now to  FIG. 3A , shown is the first outer tubular body member  10  wherein a channel  30  is formed along the outer surface  12  of the first tubular body member  10  preferably extending from a first end  16  to a second end  18  of the first inner tubular body member  10 . It is to be understood and appreciated the channel  30  may be formed along the outer surface  12  of the first inner tubular body member  10  using any suitable process for doing so (e.g., via a router means, laser, chemical etching and the like). It is to be further understood and appreciated the channel  30  may be formed to have any desired cross-sectional configuration, such as a squared configuration  30 B ( FIG. 3B ), a circular configuration  30 C ( FIG. 3C ) or an elliptical configuration  30 D ( FIG. 3D ). As shown, the channel is formed to have a desired depth (as indicated by arrow “C”) on the outer surface  12  of the first inner tubular member  10 , which is preferably less than the thickness (as indicated by arrow “D”) defining the cylindrical wall of the first inner tubular member  10 . 
     It is to be appreciated channel  30  is formed on the outer surface  12  of first inner tubular member  10  between its first  16  and second  18  ends to any desired pattern, including helical (in which the channel would be formed to wrap around the outer surface  12  of first inner tubular member  10 ). As shown in the illustrated embodiment of  FIG. 3A , a portion of the channel  30  is formed to have a first portion  40  parallel to the longitudinal axis “A” of the first inner tubular body member  10 , a second portion  42  not parallel to the aforesaid longitudinal axis “A” and a third curved portion  44  defined between the first  40  and second  42  portions. Thus, as shown in the illustrated embodiment of  FIG. 3A , the channel  30  is formed to have portions  40 ,  46  and  49  which extend substantially along the longitudinal axis “A” and portions  42 ,  48  which extend substantially perpendicular to the longitudinal axis “A”, of the first inner tubular body member  10 , the significance of which will be apparent below. 
     Additionally, it is to be appreciated and understood that while the illustrated embodiment of  FIG. 3A  depicts a single channel  30  formed in the first inner tubular body member  10 , a plurality of such channels, with same or varying cross-sectional configurations and/or patterns, may be formed along the outer surface  12  of the first inner tubular body member  10 . For instance, with reference to another illustrated embodiment of the invention as shown in  FIG. 4 , the first inner tubular body member  10  is shown to have first, second and third  50 ,  52  and  54  channels formed along its outer surface  12 , wherein each first, second and third  50 ,  52  and  54  channel is preferably formed in a nested relationship to one another. 
     Once the desired channels are formed on the outer surface  12  of the first inner tubular body member  10 , the outer surface portion  12  of the first inner tubular body member  10  is preferably plated with a suitable brazing alloy (e.g., such as nickel phosphorus or nickel boron) as illustrated in  FIG. 5 . Next, and with reference to  FIG. 6 , the second outer tubular member  20  is fitted about, and preferably brazed to, the outer surface  12  of the first inner tubular member  10  so as to provide a top seal (e.g., the inner surface  24  of the second outer tubular member  20 ) to each aforesaid channel  30  formed on the outer surface  12  of the first inner tubular body member  10 . Thus, each aforesaid channel  30  formed on the outer surface  12  of the first inner tubular body member  10  now forms a liquid passage or fluid conduit with the first and second fitted tubular members  10 ,  20  now forming a unitary structure. It is to be appreciated and understood that the aforesaid affixation of the second outer tubular member  20  to the first inner tubular body member  10  is not to be limited to a brazing process but rather may include any suitable means for affixation of the first and second tubular body members  10  and  20  to one another, including for example a welding, gluing or like a adhesive process which preferably provides a water-tight, gas-tight, and/or leak-tight seal between the affixed first and second tubular body members  10 ,  20 . 
     With reference now to  FIG. 7 , after the first and second tubular body members  10 ,  20  are affixed to one another, this assembly of the first and second tubular body members  10 ,  20  is preferably machined to remove a fluid conduit  70  formed by the channel  30  defined in the first inner tubular member  10  with the second outer tubular member  20  sealed thereto. Preferably, the fluid conduit  70  is machined from the assembly of the first and second tubular body members  10 ,  20  so as to only include enough supporting material from each aforesaid tubular body member  10 ,  20  to provide the necessary strength required for the intended function of the fluid conduit  70 . It is to be appreciated that machining the fluid conduit  70  from the assembly of the first and second tubular body members  10  and  20  is not to be understood as the only process for doing so, as any suitable process (e.g., laser cutting) may be utilized. Additionally, if the assembly of the first and second tubular body members  10 ,  20  is to produce multiple fluid conduits arising from an embodiment where the first outer tubular member  10  is formed with multiple channels ( FIG. 4 ), the aforesaid process is repeated with respect to each respective channel so as to produce a respective fluid conduit. For instance, in the illustrated embodiment of  FIG. 4  in which three channels  50 ,  52  and  54  are formed in the outer surface  12  of the first inner tubular member  10 , three distinct fluid conduits would result, wherein each fluid conduit may be affixed for use in nested relationship to one another. An illustrative environment of use for a fluid conduit  70  is shown in  FIG. 8  depicting a fuel injector assembly as used in a power generation gas turbine engine. 
     It is to be appreciated and understood each portion (e.g.,  40 ,  42 ,  44 ,  46 ,  48  and  49 ) of the resultant fluid conduit  70  is flexible, thus the fluid conduit  70  is expandable along multiple axis&#39;. Hence, one use of fluid conduit  70  is as a fuel delivery component having a resultant geometry providing a more reliable end position and stress profile than a conventional fuel tube requiring multiple bends. 
     Although illustrated embodiments of the present invention has been described, it should be understood that various changes, substitutions, and alterations can be made by one of ordinary skill in the art without departing from the scope of the present invention. For instance, the invention is not to be understood to be limited for use with a single layer of fluid or gas channels but rather may be used with numerous layers of embedded fluid or gas channels with each being joined in a similar process as described above.