Abstract:
Systems for inspecting clearances in a machine are disclosed. In one embodiment, an apparatus for inspecting a clearance in a machine includes: a base bracket configured to be disposed upon at least one rotor land within the machine; an optical device disposed upon the base bracket, the optical device for capturing an image of at least a portion of the machine wherein the image depicts at least one clearance in the machine; and a computing device communicatively connected to the optical device, the computing device for obtaining and processing the image of at least a portion of the machine from the optical device and determining at least one clearance value from the image.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The subject matter disclosed herein relates to machines and, more particularly, to a system for inspecting clearances in machines, particularly turbines. 
         [0002]    Some power plant systems, for example certain nuclear, simple-cycle and combined-cycle power plant systems, employ turbines in their design and operation. These turbines include rotors which are used to convert thermal energy into rotary motion for use and conversion by power plant systems and generators. These rotors are located within a diaphragm and are driven by a gas (i.e. steam) traveling through the diaphragm. To increase efficiency of the turbine, clearances between turbine elements are minimized and packing elements are used to seal and disrupt channels where the gas may avoid driving the rotors, instead directing a maximum amount of the gas flow into the rotors. Thermal variances and prolonged turbine use have an effect on these clearances, causing diaphragm dishing and both turbine and packing elements to undergo physical changes. The expansion, contraction, damage and wear of turbine and packing elements which comes from turbine operation may cause deviations from the original operational clearances designed for these elements. Further, diaphragm dishing may cause variances in clearances, increased outage costs and inefficient operation. The repair time and costs associated with these clearance variances increase the longer they go undetected. Therefore, it is desirable to quickly, accurately and reliably measure the clearances within a turbine, thereby enabling early detection and correction of clearance variances. Some power plant systems measure clearances manually by use of a taper gage, requiring a technician to slide a tapered instrument into the clearances between the turbine and packing elements and then read and record the measurement. However, these systems are imprecise, time consuming and susceptible to human error, they also fail to provide an accurate, reviewable record of clearances. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0003]    Systems for inspecting clearances in a machine are disclosed. In one embodiment, an apparatus for inspecting a clearance in a machine includes: a base bracket configured to be disposed upon at least one rotor land within the machine; an optical device disposed upon the base bracket, the optical device for capturing an image of at least a portion of the machine wherein the image depicts at least one clearance in the machine; and a computing device communicatively connected to the optical device, the computing device for obtaining and processing the image of at least a portion of the machine from the optical device and determining at least one clearance value from the image. 
         [0004]    A first aspect of the disclosure provides an apparatus for inspecting a clearance in a machine includes: a base bracket configured to be disposed upon at least one rotor land within the machine; an optical device disposed upon the base bracket, the optical device for capturing an image of at least a portion of the machine wherein the image depicts at least one clearance in the machine; and a computing device communicatively connected to the optical device, the computing device for obtaining and processing the image of at least a portion of the machine from the optical device and determining at least one clearance value from the image. 
         [0005]    A second aspect provides an inspection system including: a base bracket configured to be disposed upon at least one rotor land within a machine; an optical device disposed upon the base bracket, the optical device for capturing an image of at least a portion of the machine; and at least one computing device communicatively connected to the optical device, the at least one computing device adapted to inspect the machine by performing actions comprising: obtaining an image of the machine from the optical device; converting pixels in the image into known measurable dimensions; and determining clearance values of the machine from the image. 
         [0006]    A third aspect provides a turbine imaging device comprising: a computing device configured to process an image of a turbine to determine at least once clearance value; an optical device communicatively connected to the computing device, the optical device configured to capture an image of the turbine and transmit the image to the computing device; and a base bracket system fluidly connected to the optical device, the base bracket system including: a first base member configured to be disposed upon a first rotor land within the turbine; a second base member operably connected to the first base member and configured to be disposed upon a second rotor land within the turbine; and an optical device mount disposed upon either or both of the first base member and the second base member. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    These and other features of this invention will be more readily understood from the following detailed description of the various aspects of the invention taken in conjunction with the accompanying drawings that depict various embodiments of the invention, in which: 
           [0008]      FIG. 1  shows a schematic top view of an embodiment of an apparatus for inspecting a clearance in a machine in accordance with an aspect of the invention; 
           [0009]      FIG. 2  shows a schematic top view of an embodiment of a base bracket system in accordance with an aspect of the invention; 
           [0010]      FIG. 3  shows a schematic top view of an embodiment of a base bracket system in accordance with an aspect of the invention; 
           [0011]      FIG. 4  shows a schematic top view of an embodiment of a base bracket system in accordance with an aspect of the invention; 
           [0012]      FIG. 5  shows a schematic top view of an embodiment of an apparatus for inspecting a clearance in a machine in accordance with an aspect of the invention; 
           [0013]      FIG. 6  shows a schematic side view of an embodiment of an apparatus for inspecting a clearance in a machine in accordance with an aspect of the invention; 
           [0014]      FIG. 7  shows a schematic top view of some of the operational clearances in a turbine system in accordance with an aspect of the invention; 
           [0015]      FIG. 8  shows a schematic top view of an embodiment of an apparatus for inspecting a clearance in a machine in accordance with an aspect of the invention; 
           [0016]      FIG. 9  shows a schematic view of an embodiment of portions of a multi-shaft combined cycle power plant in accordance with an aspect of the invention; and 
           [0017]      FIG. 10  shows a schematic view of an embodiment of a single shaft combined cycle power plant in accordance with an aspect of the invention. 
       
    
    
       [0018]    It is noted that the drawings of the disclosure may not be to scale. The drawings are intended to depict only typical aspects of the disclosure, and therefore should not be considered as limiting the scope of the disclosure. In the drawings, like numbering represents like elements between the drawings. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0019]    As indicated above, aspects of the invention provide for systems configured to inspect clearances in a machine, (for example, e.g. a driving machine, a turbine, a gas turbine, a steam turbine, a compressor, a generator etc.) by using an optical device. The optical device (i.e. a digital camera, borescope, etc.) is positioned on a base bracket at a set horizontal and vertical distance and a set orientation relative to at least a portion of the machine, the set horizontal and vertical distances and set orientation being known by a computing device communicably connected to the optical device. The optical device is used to capture an image of at least a portion of the machine, thereby creating an accurate record of any element positions and clearances depicted in the image. The image is transmitted to the computing device where, based upon the known resolution, dimensions and orientation, the pixels in the image are then converted into measurable dimensions by the computing device and any of a number of clearance values in the image are determined based upon the converted pixels. 
         [0020]    In the art of power generation systems (including, e.g., nuclear reactors, steam turbines, gas turbines, etc.), machines with small working clearances are often employed as part of the system. For instance, turbines with encased rotors are often used to drive a power generator for the purpose of generating electricity. Typically, the elements within the turbine, including the rotor and casing operate with small working clearances to maximize efficiency, even including packing elements in design and construction to seal and reduce clearances and channels within the turbine where gas may avoid driving the rotors. By reducing the clearances between the various elements of the turbine, more gas is forced to travel through, and subsequently drive, the rotors instead of leaking through these clearances. However, as the turbine is operated, the clearances between elements begin to vary in size, becoming larger or smaller as operational lifetime extends, resulting in wear or damage to the turbine, poor outage quality, diaphragm dishing, diaphragm creep, inefficient operation, longer outage times, higher repair costs, etc. These clearance variances are difficult to detect and accurately record and their negative effects are amplified over time, e.g. the longer they go undetected by operators the greater the costs to the system. 
         [0021]    Turning to the FIGURES, embodiments of a clearance inspection system for a machine such as a turbine are shown, where the clearance inspection system may allow for increases in efficiency and life expectancy of the diaphragm, the rotors, the turbine and the overall power generation system by quickly and accurately identifying clearances between turbine elements which vary from designed operational clearance values. Each of the components in the FIGURES may be connected via conventional means, e.g., via a wired communication, wireless communication, common conduit or other known means as is indicated in  FIGS. 1-10 . Specifically, referring to  FIG. 1 , a schematic top view of a clearance inspection system  100  in accordance with an aspect of the invention is shown. Clearance inspection system  100  may include a first base member  110  operably connected to a second base member  120 , an optical device  190  disposed upon either or both of first base member  110  and second base member  120  and a computing device  192  communicatively connected to optical device  190 . Clearance inspection system  100  may be disposed upon a portion of a turbine  102 , where first base member  110  and second base member  120  may be in contact with turbine  102  positioning optical device  190  at a set orientation and horizontal and vertical distance relative to at least this portion of turbine  102 . The set orientation, horizontal and vertical distances being known by computing device  192 . Optical device  190  may capture an image of at least a portion of turbine  102 , thereby creating a reviewable image which may be processed by computing device  192 . Computing device  192  may convert pixels in the image into measurable dimensions by considering the resolution of optical device  190  and the known orientation and horizontal and vertical distances of optical device  190  relative to turbine  102 . Computing device  192  may compute clearance values for elements of turbine  102  by considering the converted pixels in the image which represent the clearances. In another embodiment, computing device  192  may include a memory  194  for storing the image. In another embodiment, memory  194  may store the image for local or remote processing. Attachment upon turbine  102  and image processing by computing device  192  may be accomplished in any number of ways as is known in the art or discussed further below. 
         [0022]    In an embodiment of the present invention, optical device  190  may be positioned at a center of clearance inspection system  100  between first base member  110  and second base member  120 . In one embodiment, pixels in images captured by optical device  190  may be pre-converted to known measurable lengths stored in memory  194  on computing device  192 . It is understood that optical device  190  may include a camera, a borescope, etc. It is understood that computing device  192  may include a plurality of computing devices. 
         [0023]    Turning to  FIG. 2 , a schematic top view of a base bracket system  200  is shown according to embodiments of the invention. It is understood that in embodiments shown and described with reference to  FIGS. 2-10 , like numbering may represent like elements and that redundant explanation of these elements has been omitted for clarity. Finally, it is understood that the components of  FIGS. 1-10  and their accompanying descriptions may be applied to any embodiment described herein. Returning to  FIG. 2 , in this embodiment, base bracket system  200  may include an optical device mount  230  which may be disposed upon either or both of first base member  110  and second base member  120 . In this embodiment, first base member  110  and second base member  120  are configured to be disposed upon rotor  240 . In one embodiment, first base member  110  and second base member  120  may be configured to be disposed upon rotor lands  242 , positioning optical device mount  230  a known distance and orientation relative to either or both of rotor  240  and rotor lands  242 . In one embodiment, first base member  110  and second base member  120  may be configured to position optical device mount  230  a known distance and orientation relative to either or both of large packing teeth  252  and small packing teeth  254 . In another embodiment, a width of base bracket system  200  may be adjustable. 
         [0024]    Turning to  FIG. 3 , a schematic top view of a base bracket system  300  is shown according to embodiments. In this embodiment, base bracket system  300  includes adjustment system  322  for adjusting the positions of first base member  110  and second base member  120  relative to one another. In this embodiment, adjustment system  322  may be used to adjust the width of base bracket system  300  relative to rotor lands  242 . In one embodiment, first base member  110  and second base member  120  may be adjusted evenly relative to a center-point  327  of base bracket system  300 . In one embodiment, adjustment system  322  may include a geared apparatus  324  between first base member  110  and second base member  120 , where the geared apparatus  324  is configured to evenly adjust both first base member  110  and second base member  120  about center-point  327 . In another embodiment, first base member  110  and second base member  120  may be adjustable relative to one another such that base bracket system  300  may be disposed upon any of a number of rotor lands  242 . In one embodiment, first base member  110  and second base member  120  may slide together or apart to adjust the width of base bracket system  300 . In another embodiment, first base member  110  and second base member  120  may be disposed upon rotor  240  such that base bracket system  300  brackets an even number of rotor lands  242 . In another embodiment, base bracket system  300  may be disposed upon rotor  240  such that center-point  327  is located at a centerline  328  (shown in phantom) between two rotor lands  242 . In another embodiment, adjustment system  322  may enable base bracket system  300  to be interchangeable between different types of turbines. 
         [0025]    Turning to  FIG. 4 , a schematic top view of an embodiment of a base bracket system  400  is shown according to embodiments of the invention having a directional indicator  445  disposed upon first base member  110 . Directional indicator  445  may be configured to indicate an orientation of rotor  140  relative to base bracket system  400 . In one embodiment, directional indicator  445  may be disposed upon either or both of first base member  110  and second base member  120 . In another embodiment, directional indicator  445  may be formed as an arrow. In another embodiment, directional indicator  445  may be adjustable. In another embodiment, directional indicator  445  may include a digital display. In another embodiment, directional indicator  445  may be affixed upon rotor  240 . 
         [0026]    Turning to  FIG. 5 , a schematic top view of a clearance inspection system  500  according to embodiments of the invention is shown having a borescope  550  disposed within an optical device mount  554 . In one embodiment, optical device mount  554  positions borescope  550  at a center of base bracket system  200 . In another embodiment, optical device mount  554  may comprise an optical device casing. In another embodiment, optical device mount  554  may secure borescope  550  in a fixed position. In another embodiment, optical device mount  554  may be adjustable. In another embodiment, optical device mount  554  may configure borescope  550  such that a focal point  582  of borescope  550  is located approximately halfway between a set of rotor lands  242  of rotor  240 . In another embodiment, optical device mount  554  may be rotatable about focal point  582 . In another embodiment, an additional known distance M between rotor packing lands  242  may be obtained from turbine design materials and entered into computing device  192  to assist with converting pixels to measurable dimensions. 
         [0027]    Turning to  FIG. 6 , a schematic side view of an embodiment of a clearance inspection system  600  according to embodiments of the invention is shown. This illustrates positioning borescope  550  at known distances C and D and angle α relative to a portion of turbine  102 . Base bracket system  200  may be disposed upon portions of turbine  102  such that optical device mount  554  consistently configures borescope  550  at known angle α, vertical height D and horizontal distance C relative portions of turbine  102 . In one embodiment of the invention, borescope  550  may capture an image of at least a portion of turbine  102  which may be processed by computing device  192 . In one embodiment, computing device  192  may convert pixels in the image into known measurable dimensions by considering the resolution of borescope  550 , distances C and D and angle α. In another embodiment, computing device  192  may have the resolution of borescope  550 , set distances C and D and set angle α stored on memory  194  such that pixels in images captured by borescope  550  may be pre-converted into known measureable distances stored on memory  194 . 
         [0028]    Turning to  FIG. 7 , a schematic top view illustrating some example axial clearance values A and B is shown according to embodiments of the invention. The values A and B may represent distances between rotor lands  242  of rotor  240  and packing teeth  252 . In one embodiment, optical device  190  may be configured with focal point  582  at a center of rotor lands  242  such that A and B will be computable by computing device  192 . 
         [0029]    Turning to  FIG. 8 , a schematic top view of a clearance inspection system  800  is shown according to embodiments of the invention. In this embodiment, clearance inspection system  800  is shown having a rotational optical device casing  880  and a rotational directional indicator  882  disposed upon base bracket system  200 . Rotational optical device casing  880  may be configured to dispose optical device  190  upon base bracket system  200 . In one embodiment, clearance inspection system  800  may include a rotational directional indicator  882  disposed upon rotational optical device casing  880 , rotational directional indicator  882  being configured to be visible in and indicate an orientation of images captured by optical device  190 . In one embodiment, rotational optical device casing  880  may be configured to rotate optical device  190  while maintaining a constant focal point position  582  with relation to rotor  140 . In another embodiment, rotational directional indicator  882  may rotate with optical device  190  and rotational optical device casing  880 . 
         [0030]    Turning to  FIG. 9 , a schematic view of portions of a multi-shaft combined-cycle power plant  900  is shown. Combined-cycle power plant  900  may include, for example, a gas turbine  942  operably connected to a generator  944 . Generator  944  and gas turbine  942  may be mechanically coupled by a shaft  911 , which may transfer energy between a drive shaft (not shown) of gas turbine  942  and generator  944 . Gas turbine  942  may be operably connected to clearance inspection system  100  of  FIG. 1  or other embodiments described herein. Also shown in  FIG. 9  is a heat exchanger  946  operably connected to gas turbine  942  and a steam turbine  948 . Heat exchanger  946  may be fluidly connected to both gas turbine  942  and steam turbine  948  via conventional conduits (numbering omitted). Heat exchanger  946  may be a conventional heat recovery steam generator (HRSG), such as those used in conventional combined-cycle power systems. As is known in the art of power generation, HRSG  946  may use hot exhaust from gas turbine  942 , combined with a water supply, to create steam which is fed to steam turbine  948 . Steam turbine  948  may optionally be coupled to a second generator system  944  (via a second shaft  911 ). It is understood that generators  944  and shafts  911  may be of any size or type known in the art and may differ depending upon their application or the system to which they are connected. Common numbering of the generators and shafts is for clarity and does not necessarily suggest these generators or shafts are identical. Generator system  944  and second shaft  911  may operate substantially similarly to generator system  944  and shaft  911  described above. Steam turbine  948  may be fluidly connected to clearance inspection system  100  of  FIG. 1  or other embodiments described herein. In one embodiment of the present invention (shown in phantom), clearance inspection system  100  may be used to inspect clearances in either or both of steam turbine  948  and gas turbine  942  during an outage. In another embodiment, two clearance inspection systems  100  may be operably connected to combined-cycle power plant  900 , one clearance inspection system  100  for each of gas turbine  942  and steam turbine  946 . In another embodiment, shown in  FIG. 10 , a single-shaft combined-cycle power plant  990  may include a single generator  944  coupled to both gas turbine  942  and steam turbine  946  via a single shaft  911 . Gas turbine  942  and steam turbine  946  may be fluidly connected to clearance inspection system  100  of  FIG. 1  or other embodiments  200 ,  300 ,  400 ,  500 ,  600 ,  700 ,  800  or  900  described herein. 
         [0031]    The clearance inspection system of the present disclosure is not limited to any one particular machine, driven machine, turbine, fan, blower, compressor, power generation system or other system, and may be used with other power generation systems and/or systems (e.g., combined-cycle, simple-cycle, nuclear reactor, etc.). Additionally, the clearance inspection system of the present invention may be used with other systems not described herein that may benefit from the early detection, inspection, imaging, recording, and measurement capabilities of the turbine clearance inspection system described herein. 
         [0032]    The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
         [0033]    This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.