Patent Publication Number: US-8528207-B2

Title: Variable vane calibration method

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a method for calibrating compressor and/or turbine variable vanes in a turbine engine and a kit for executing the method. 
     2. Description of Related Prior Art 
     U.S. Pat. No. 4,307,994 discloses a variable vane position adjuster. In the &#39;994 patent, a compressor vane adjustment assembly for calibrating the nozzle/throat width dimension between adjacent adjustable vanes in a nozzle vane ring assembly and for producing conjoint rotation of the individual vane following their calibration includes a vane stem that extends outwardly of a compressor case and further includes a motion converting sleeve in surrounding relationship thereto and “coacting” means between the sleeve and the vane stem that concurrently rotates both the sleeve and the stem and also provides relative axial movement of the sleeve with respect to the vane stem; the adjustment assembly further includes an actuator arm for rotating each of the vanes and means for connecting the actuator arm to the sleeve to cause angular positioning of the actuator arm to be directly transmitted to each of the vanes following calibration thereof. A calibration adjustment nut is located at a point accessible from externally of the compressor case and is associated with the sleeve and operative to axially position it on the vane stem and wherein coacting means on the sleeve and the actuator arm are responsive to axial positioning of the sleeve on the vane stem to rotate it relative to the actuator arm so that the vane stem can be prepositioned to selectively vary the throat width clearance between selected ones of adjacent nozzle vanes in the assembly. 
     SUMMARY OF THE INVENTION 
     In summary, the invention is a method and kit for confirming the position of at least one variably positionable vane, such as a compressor vane. The method includes the step of mounting at least one camera on an exterior of an at least partially assembled turbine engine. The method also includes the step of generating visual data with the at least one camera corresponding to a position of a turbine vane actuation structure positioned on the exterior of the at least partially assembled turbine engine. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: 
         FIG. 1  is a schematic cross-section of a turbine engine with variable vanes that can be calibrated according to an exemplary embodiment of the invention; 
         FIG. 2  is an exploded view of a calibration module, camera, and fixture of a kit according to an embodiment of the invention; 
         FIG. 3  is a perspective view of a camera and fixture according to an embodiment of the invention; 
         FIG. 4  is a top view of the camera and fixture shown in  FIG. 3 ; 
         FIG. 5  is a plan view of the kit shown in  FIG. 2  applied to an at least partially assembled turbine engine; and 
         FIG. 6  is an exemplary screen shot that can be displayed by an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF AN EXEMPLARY EMBODIMENT 
     The invention, as demonstrated by the exemplary embodiment described below, provides an enhanced calibration method such that the positions of variable turbine vanes can be controlled so precisely that other engine parameters can be modified upon reliance of this precision. Analog gages have been used to control/calibrate the position of variable turbine vanes. However, analog gages require a human assembler to read a value corresponding to the positions of the vanes (which are defined by angles). If the analog gage is misread (rotated 180 degrees), the human assembler can be fooled. Digital gages are currently used in place of analog gages. However, digital gages are less precise than analog gages in the sense that digital gages consume more of the tolerance of the vane position. For example, an analog gage can consume around twenty-eight percent of the tolerance of the vane position. In other words, when the analog gage indicates that a vane is in a particular position, the true vane position is within a band or range of values defined by about twenty-eight percent of the overall tolerance for the vane position. The vane&#39;s position is ±14% of the value displayed by the analog gage. When the digital gage indicates that a vane is in a particular position, the true vane position is within a band or range of values defined by about eighty percent of the overall tolerance for the vane position. The vane&#39;s position is ±40% of the value displayed by the digital gage. 
     The embodiment of the invention described below consumes about thirteen to seventeen percent of the tolerance of the vane position. This level of precision yields a higher level of control over the vane position and allows other parts of the turbine engine be designed and/or operated over a broader range and at a higher level of performance. In one embodiment, the physical rpm of a turbine engine was decreased by thirty rpm after the vanes were calibrated, while producing the same amount of power. Also, embodiments of the invention have reduced calibration time by about one hour per engine. 
       FIG. 1  schematically shows a turbine engine  10 . The various unnumbered arrows represent the flow of fluid through the turbine engine  10 . The turbine engine  10  can produce power for several different kinds of applications, including vehicle propulsion and power generation, among others. The exemplary embodiments of the invention disclosed herein, as well as other embodiments of the broader invention, can be practiced in any configuration of a turbine engine and in any application other than turbine engines in which inspection of difficult to access components is desired or required. 
     The exemplary turbine engine  10  can include an inlet  12  to receive fluid such as air. The turbine engine  10  can include a fan to direct fluid into the inlet  12  in alternative embodiments of the invention. The turbine engine  10  can also include a compressor section  14  to receive the fluid from the inlet  12  and compress the fluid. The compressor section  14  can be spaced from the inlet  12  along a centerline axis  16  of the turbine engine  10 . The turbine engine  10  can also include a combustor section  18  to receive the compressed fluid from the compressor section  14 . The compressed fluid can be mixed with fuel from a fuel system  20  and ignited in an annular combustion chamber  22  defined by the combustor section  18 . The turbine engine  10  can also include a turbine section  24  to receive the combustion gases from the combustor section  18 . The energy associated with the combustion gases can be converted into kinetic energy (motion) in the turbine section  24 . 
     In  FIG. 1 , shafts  26 ,  28  are shown disposed for rotation about the centerline axis  16  of the turbine engine  10 . Alternative embodiments of the invention can include any number of shafts. The shafts  26 ,  28  can be journaled together for relative rotation. The shaft  26  can be a low pressure shaft supporting compressor blades  30  of a low pressure portion of the compressor section  14 . A plurality of vanes  31  can be positioned to direct fluid downstream of the blades  30 . The shaft  26  can also support low pressure turbine blades  32  of a low pressure portion of the turbine section  24 . For example, the high pressure turbine can be associated with shaft  28  can provide power to drive the compressor section  14  and the low pressure turbine associated with shaft  26  can provide power to the propeller, fan or shaft. 
     The shaft  28  encircles the shaft  26 . As set forth above, the shafts  26 ,  28  can be journaled together, wherein bearings are disposed between the shafts  26 ,  28  to permit relative rotation. The shaft  28  can be a high pressure shaft supporting compressor blades  34  of a high pressure portion of the compressor section  14 . A plurality of vanes  35  can be positioned to receive fluid from the blades  34 . The shaft  28  can also support high pressure turbine blades  36  of a high pressure portion of the turbine section  24 . A plurality of vanes  37  can be positioned to direct combustion gases over the blades  36 . 
     The compressor section  14  can define a multi-stage compressor, as shown schematically in  FIG. 1 . A “stage” of the compressor section  14  can be defined as a pair of axially adjacent blades and vanes. For example, the vanes  31  and the blades  30  can define a first stage of the compressor section  14 . The vanes  35  and the blades  34  can define a second stage of the compressor section  14 . The invention can be practiced with a compressor having any number of stages. 
     A casing  38  defines a first wall and can be positioned to surround at least some of the components of the turbine engine  10 . The exemplary casing  38  can encircle the compressor section  14 , the combustor section  18 , and the turbine section  24 . In alternative embodiments of the invention, the casing  38  may encircle less than all of the compressor section  14 , the combustor section  18 , and the turbine section  24 . 
       FIG. 1  shows the turbine engine  10  having a fan  40  positioned forward of the compressor section  14  along the centerline axis  16 . The fan  40  can include a plurality of blades  42  extending radially outward from a hub  44 . The fan  40  can be encircled by a fan case  46 . The fan case  46  can be fixed to the casing  38 . The casing  38  is shown schematically as being a single structure. In some embodiments of the invention, the casing  38  can be a single structure. In other embodiments of the invention, the casing  38  can be formed from a plurality of members that are fixed together. The forward-most member can be designated as a “front frame.” The fan case  46  can be mounted to a front frame portion of the casing  38 . 
       FIG. 1  also shows that the vanes  31  and  35  can be variable. In other words, the vanes  31 ,  35  can be pivoted about respective axes to vary the flow of fluid through the turbine engine  10 . The turbine engine  10  can also include inlet guide vanes  48  that can be pivoted about respective axes to vary the flow of fluid through the turbine engine  10 . For example, the vane  31  can include a stem  50  centered on an axis  52 . It is noted that the two vanes marked  31  are distinct vanes; likewise the vanes marked  35  and  48  are distinct. The vane  31  can be pivoted about the axis  52 . The stem  50  can be pivotally connected to a link arm  54  and the link arm  54  can be connected to a ring  56 . The ring  56  can be rotated about the axis  16 . Rotation of the ring  56  about the axis  16  can cause the link arm  54  to pivot and thereby move the vane  31  about the axis  52 . 
       FIG. 2  is an exploded view of kit for confirming the position of the vanes, such as vanes  31 ,  35 , and  48  shown in  FIG. 1 . The method and kit according to the exemplary embodiment of the invention can be applied to turbine engines that are fully assembled and to turbine engines that are less than fully assembled. The exemplary embodiment has been applied to turbine engines intended for aircraft propulsion, but the exemplary embodiment and other embodiments of the invention can be applied to turbine engines in other operating environments. 
     The exemplary embodiment provides a method for confirming the position of variably positionable turbine vanes. The position can be “confirmed” in that a current position of one or vanes can be detected or assessed. The position can also be “confirmed” in the sense that the position can be changed to a desired or calibrated position. In the exemplary embodiment, the position of a vane corresponds to an angle, but the position could correspond to other forms of data in alternative embodiments of the invention. 
     Kits according to various embodiments of the invention can include at least one camera operable to generate visual data. The exemplary kit  58  includes first and second cameras  60 ,  62  (camera  62  is shown in  FIG. 5 ). The cameras  60 ,  62  can be substantially similar if not identical; therefore camera  60  will be described in detail and this description also applies to camera  62  in the exemplary embodiment of the invention. 
     As shown in  FIG. 3 , the camera  60  can include a lens  64  for receiving images. First and second light bars  66 ,  68  can be positioned on opposite sides of the lens  64  to enhance the capacity of the camera  60  to capture a detailed view of the structures to be observed. The camera  60  can be a Sony® XC HR70 Machine Vision Camera and incorporate a Cognex frame grabber and breakout module. The camera  60  can acquire images for assessment. The breakout module can provide an input/output interface. The frame grabber can provide power to the camera through the camera cable. The light bars  66 ,  68  can be supplied by CCS America and be controlled by a signal to a variable strength strobe controller. 
     As shown in  FIGS. 3 and 4 , a bracket or fixture  70  can be engaged with the camera  60  for mounting the camera  60  to the at least partially assembled turbine engine  10  (referenced in  FIG. 1 ). The fixture  70  can be shaped to conform to an exterior portion of the turbine engine  10 . The exemplary fixture  70  can include a mounting surface  72  operable to mate with a surface defined on an exterior of an at least partially assembled turbine engine  10  such that when the at least one camera  60  is mounted to the at least partially assembled turbine engine  10  the at least one camera  60  is positioned to generate visual data corresponding to a position of a turbine vane actuation structure positioned on the exterior of the at least partially assembled turbine engine  10 . The exemplary mounting surface  72  is arcuate and operable to conform to a radially-outer surface of the ring  56  (referenced in  FIGS. 1 and 5 ) and the turbine vane actuation structure to be observed can be the link arm  54 . 
     A turbine engine typically includes more than one vane actuation ring such as ring  56 . The mounting surface  72  can be shaped to correspond to the largest diameter of these rings so that the fixture can be mounted on all of the rings. The fixture  70  is thus operable to engage a plurality of differently-configured surfaces on the exterior of the at least partially assembled turbine engine  10 . A plurality of clamps can be positioned on the fixture  70  and the clamps can be arranged to accommodate size differences between the differently-configured surfaces on the exterior of the at least partially assembled turbine engine  10 . In the exemplary embodiment, a first clamp  74  includes a handle  76 , a rod  78  fixed to the handle  76 , a latch portion  80  fixed to the rod  78 , and a spring  82 . The rod  78  can extend through an aperture  84  in the fixture  70 . In operation, the handle  76  can be urged toward the fixture  70 , thereby compressing the spring  82 , until the latch portion  80  is radially inward of the ring  56 . The handle  76  can then be rotated until a cantilevered end of the latch portion  80  is behind the ring  56 . The handle  76  can then be released, allowing the spring  82  to bias the handle  76  radially outward and press the latch portion  80  against the radially-inner surface of the ring  56 . A second clamp  86  like the first clamp  74  can be positioned on an opposite side of the fixture  70 . It is noted that the clamps  74  and  86  are not shown in  FIG. 3  in order to more clearly show the mounting surface  72 . 
     To further enhance the stability of the camera  60 , clamps  88  and  90  can be positioned on opposite sides of the fixture  70 . The clamps  88 ,  90  can be similarly constructed. Clamp  88  can include a handle  92  with a rod (not visible) that interconnects three plates  94 ,  96 ,  98 . The plate  96  can be desirable to limit to the extent of radially-inward travel of the clamp  88  relative to the ring  56 . Turning the handle  92  in a first angular direction can cause the plates  94  and  98  to move closer together to pinch the ring  56  between the cantilevered ends of the plates  94  and  98 . Turning the handle in a second angular direction opposite the first angular direction can cause the plates  94  and  98  to move apart from one another and release the ring  56 . 
     Referring again to  FIG. 2 , the exemplary kit  58  can also include a module  100  housing a processor  102  operable to receive visual data from the at least one camera  60  and convert the visual data into a numerical value corresponding to the position of a turbine vane actuation structure. The exemplary module  100  can be a moveable structure mounted on casters  104 . The module  100  can also support a monitor screen  106  for providing a graphical user interface and display. The monitor screen  106  can be controlled by the processor  102 . The module  100  can also support a keyboard  108  and mouse  110 . Power and communication wires/cables  112 ,  114  can extend between the camera  60  and the processor  102 . 
     At the start of an exemplary method for confirming the position of at least one variably positionable turbine vane, the camera  60  can be mounted on the module  100  to calibrate (or confirm calibration of the camera  60 ). The module  100  can define a surface  116  operable to receive the mounting surface  72  of the fixture  70 . The processor  102  is operable to receive visual images from the camera  60  when the mounting surface  72  is received by the surface  116  of the module  100  and confirm a calibration of the camera  60  and the fixture  70 . 
     After calibration of the camera  60 , the camera  60  can be mounted to the at least partially assembled turbine engine  10 .  FIG. 5  shows the at least partially assembled turbine engine  10  having a plurality of vane-actuating rings, such as ring  56 . Each of the rings can be formed from two ring halves connected together to form a 360 degree ring. Each ring can be connected to a torque tube  118  by respective turnbuckles  120 . The torque tube  118  can be pivoted about its central axis  122  by an actuator  124 . When the torque tube  118  is rotated in a first angular direction, the rings rotate about the centerline axis  16  (which is parallel and spaced from the axis  122 ) in a first angular direction. When the torque tube  118  is rotated in a second angular direction opposite the first angular direction, the rings rotate about the centerline axis  16  in a second angular direction opposite the first angular direction. 
     Each ring can be pivotally connected to a plurality of link arms, such as link arm  54 . Each link arm  54  can be connected to a variable turbine vane, such as through a stem  50 . The vane rotates about an axis  52  which extends out of the page in  FIG. 5 . The camera  60  can be mounted to the ring  56  by directing a first pin  122  through one of the apertures  126 ,  128 ,  130  in the fixture  70  (see  FIGS. 3 and 4 ) and also through an aperture in the ring  56 . Also, a pin  124  can be directed through the aperture  132  in the fixture  70  (see  FIGS. 3 and 4 ) and also through an aperture in the ring  56 . The aperture  132  can be slot like to ease the assembly of both pins  122 ,  124  by simplifying alignment of the various apertures. Next, the clamps  74 ,  86 ,  88 , and  90  can be engaged as described above to fix the camera  60  to the ring  56  through the fixture  70 . The camera  60  is thus mounted on the exterior of the at least partially assembled turbine engine  10 . 
     The second camera  62  can be mounted similarly. The cameras  60 ,  62  can be spaced at least forty-five degrees apart from one another about the centerline axis  16  of the turbine engine  10 . The exemplary embodiment includes two cameras  60 ,  62 , but any number of cameras can be applied in alternative embodiments of the invention. 
     It is noted that the processor  102  can be operable to assess the visual data received from one or both cameras  60 ,  62  to confirm that the respective camera is mounted on a particular ring from among a plurality of differently-sized rings. For example, the processor  102  can be programmed with the desirable position for each variable vane. The desirable position for each vane can vary for the various stages of the compressor. Prior to placement of the cameras  60 ,  62 , the processor  102  can receive input from an operator relating to the particular compressor stage being calibrated or can dictate to the operator which stage to calibrate. The visual display observed by the camera and communicated to the processor  102  can be different for different rings because the rings are slightly different in size. When the cameras  60 ,  62  are first assembled to the ring  56 , the processor  102  can assess the visual data and if the cameras  60 ,  62  are not positioned on the appropriate ring, the processor  102  can emit an error message to the operator. 
     After the cameras  60 ,  62  are mounted on the appropriate ring of the at least partially assembled turbine engine  10 , the processor  102  can control the monitor screen  106  to provide a graphical user interface and/or display for the operator. The monitor screen  106  can display the positions of the link arms viewed by the cameras. 
       FIG. 6  shows an exemplary screen shot in which a link arm  54   a  viewed by the camera  60  is displayed and a link arm  54   b  viewed by the camera  62  is displayed. The link arm  54   a  is connected to a stem  50   a  of variable turbine vane that can rotate about a pivot axis  52   a  (extending out of the paper). The link arm  54   b  is connected to a stem  50   b  of variable turbine vane that can rotate about a pivot axis  52   b  (extending out of the paper). 
     The visual data corresponds to a position of a turbine vane actuation structure positioned on the exterior of the at least partially assembled turbine engine  10 . In the exemplary embodiment, the turbine vane actuation structure is a link arm for both cameras  60 ,  62 . Other structures can be observed in alternative embodiments of the invention. The respective positions of the link arms  54   a  and  54   b  are defined by angles referenced at  134  and  136  respectively. The angles  134 ,  136  are defined between respective longitudinal axes  138 ,  140  of the link arms  54   a ,  54   b  and respective longitudinal axes  142 ,  144  of the at least partially assembled turbine engine  10 . A longitudinal axis of the turbine engine  10  can extend between a forward end of the turbine engine  10  and an aft end. The centerline axis  16  of the turbine engine  10  is one longitudinal axis of the turbine engine. In  FIG. 6 , the respective axes  142 ,  144  extend parallel to and spaced from the centerline axis  16  shown in  FIG. 1 . 
     The positions of the link arms  54   a ,  54   b  can be shown relative to one another in a field defining at least two of preferred values, acceptable values, and unacceptable values.  FIG. 6  shows a portion of the graphical display being a field  146 . An exemplary initial value for the angle referenced at  134  is shown to be “17.54.” An exemplary initial value for the angle referenced at  136  is shown to be “17.77.” The average of these two values is shown to be “17.68.” These values are positioned in the field  146 . The field  146  can be divided into different-colored areas. In  FIG. 6 , the areas are distinguished by solid horizontal lines. Areas  148  and  150  can be colored red to represent values that are out of tolerance. Areas  152  and  154  can be colored yellow to represent values that are acceptable but not preferred. Area  156  can be colored green to represent values that are preferred. In the example, the angle  134  associated with the link arm  54   a  is out of tolerance and the angle  136  associated with the link arm  54   b  is within tolerance but not preferred. The average of the two values is out of tolerance. 
     The positions of the link arms  54   a ,  54   b  can be assessed and then adjusted. Referring again to  FIG. 5 , the turnbuckle  120  can be adjusted to adjust the positions of the ring  56  relative to the torque tube  118  such that the average of the positions of the link arms  54   a ,  54   b  changes to a desired value. During adjustment, the processor  102  can be adjusting the values displayed in the field  146  in real time. For example, the numerical values displayed in the field  146  can change and the positions of the values within the field  146  can change. At the completion of adjustment in the example, an exemplary final value for the angle referenced at  134  is shown to be “18.37,” an exemplary final value for the angle referenced at  136  is shown to be “18.54,” and the average of these two values is shown to be “18.46.” During adjustment, the values were moving upward and changing. After adjustment all of the values are now within acceptable tolerances and the value of angle  136  is preferred. The average of the values is almost preferred. Embodiments of the invention can be practiced in numerous ways. For example, the turnbuckle  120  can be adjusted until the average of the angles is preferred. 
     After the final positions are established, the ring  56  can be moved between first and second opposite end limits of travel by the torque tube  118 , returning to the initial position to ensure the modified link arm positions remain established at the adjusted values. The cameras  60 ,  62  can continue to generate visual data for processing by the processor  102  and for display on the monitor  106  during this movement. After the vanes connected to the first ring  56  have thus been calibrated, the first and second cameras  60 ,  62  can be disconnected from the ring  56  and mounted to a second ring  158  spaced from the ring  56  along the centerline axis. The first and second cameras  60  and  62  are thus connectible to both the first and second rings  56 ,  158  with the same fixture  70 . 
     It is noted that components for producing embodiments of the invention can be acquired from Clarke Engineering Services, Inc., located at 9114 Technology Lane, Fishers, Ind. 46038-2839. 
     While the invention has been described with reference to an exemplary embodiment, 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. Further, the “invention” as that term is used in this document is what is claimed in the claims of this document. The right to claim elements and/or sub-combinations that are disclosed herein as other inventions in other patent documents is hereby unconditionally reserved.