Abstract:
A tool is provided for use in removing at least one airfoil. The tool includes a skid for mounting tool components, a vibrator attached to the skid, at least one jaw connected to a jaw activator. The jaw is configured to engage the airfoil. Power supply means are provided for powering the tool.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Application Ser. No. 61/170,236, titled “Apparatus And Tools For Use With Compressors” and filed on Apr. 17, 2009. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates to compressors and particularly relates to apparatus for repairing or upgrading components in compressors. 
         [0003]    In axial flow compressors, stator vanes alternate with rotating blades or buckets in the various stages of the compressor. The stator vanes are circumferentially spaced one from the other about the compressor axis and are secured to the upper and lower compressor casing halves. The upper and lower casing halves are joined one to the other at the compressor midline and provide a complete circumferential array of stator vanes for each compressor stage. As each rotating blade mounted on the rotor completes each revolution at a given rotational velocity, the rotating blade receives aerodynamic excitation pulses from each stator vane. This pulse can be generated from the wake of the upstream stator vane or the bow wave of the downstream stator vane. It is also possible to generate excitations in the rotating blade from differences between the upstream and downstream stator vane counts. These pulses induce a vibratory response in the rotating blade that can be deleterious to the rotating blade causing failure due to high cycle fatigue. 
         [0004]    Typically the stator vane or blade count in the upper and lower halves of the compressor casing for a given stage are equal in number to one another. For example, in an initial stage S 0  of a given compressor, the blade count for the stator vanes in each of the upper and lower compressor casing halves may be 24/24. In the next stage S 1 , the blade count may be 22/22. The first number represents the number of stator vanes in the upper casing half and the second number represents the number of stator vanes in the lower casing half of the same stage. The total stator vane count in S 0  and S 1  is therefore forty-eight and forty-four stator vanes respectively. However, because of the vibratory responses of the rotating blades, non-uniform vane spacings between upper and lower casing halves have been used in the past. Thus, different and alternative upper and lower blade counts in succeeding stages have been provided to reduce or eliminate the vibratory response. For example, in one compressor, stages S 0  and S 1  have had vane counts of 24/23 and 23/24, respectively. These non-uniform blade counts have been used in original equipment manufacture. 
         [0005]    There are, however, a significant number of compressors in use in the field where there is an equal number of stator vanes in the upper and lower compressor halves for given stages. Certain other compressors in the field have an unequal number of stator vanes in the upper and lower compressor halves with adjacent stages, e.g. S 0  and S 1 , having equal numbers of blades but alternate blade counts between the upper and lower halves of the compressor casing. Changing blade counts in the field was not previously considered practical since costly removal of the rotor in the field was required. 
         [0006]    Because the rotor is closely fitted to the middle and aft (or rearward) sections of the compressor, it is geometrically difficult to reach the areas where the blades reside or to drill, tap, and counter-bore load dam pin holes in the area desired. Additionally, the current known methods for removal of these blades increase the likelihood that the rotor, stator blades or adjacent hardware may be damaged during the removal process. Moreover, the extended reach and limited access to the stator blades being removed underneath the rotor and rotor blades creates an ergonomic issue potentially leading to operator injury. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0007]    In accordance with one aspect of the present invention, a tool is provided for use in removing at least one airfoil. The tool includes a skid for mounting tool components, a vibrator attached to the skid, and at least one jaw connected to a jaw activator. The jaw is configured to engage the airfoil. A power supply is used for powering the tool. 
         [0008]    In accordance with another aspect of the present invention, a tool is provided for use in removing at least one airfoil. The tool includes a skid for mounting tool components and the skid is configured to engage and slide along at least one groove in a case of a dynamoelectric machine. A vibrator is attached to the skid, and at least one jaw is connected to a jaw activator. The at least one jaw is configured to engage the airfoil. A power supply is used for powering the tool. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a schematic illustration with parts broken out for clarity of the upper half of a compressor illustrating various compressor stages; 
           [0010]      FIG. 2  is a perspective view of stage S 0  and stage S 1  with rotating blades or buckets therebetween, illustrating the different blade counts in the upper and lower compressor halves of these stages; 
           [0011]      FIG. 3  is a schematic end view illustrating a compressor having an equal stator vane count in both upper and lower halves of the compressor stage; and 
           [0012]      FIG. 4  is a schematic illustration of the removal of the upper compressor half; 
           [0013]      FIG. 5  is a perspective illustration of a tool that can be used to remove a stator vane, according to one aspect of the present invention; 
           [0014]      FIG. 6  is a perspective illustration of a tool grasping a blade, and a portion of the hook fit slot in a compressor case, according to an aspect of the present invention; 
           [0015]      FIG. 7  is a perspective illustration of extension handles that may be used in conjunction with the tool of  FIG. 5 , according to an aspect of the present invention. 
           [0016]      FIG. 8  is a block diagram of a power and control system that may be used in conjunction with the tool of  FIG. 5 , according to an aspect of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0017]    Referring to  FIG. 1 , there is illustrated an upper half of a compressor generally designated  10 . Compressor  10  includes a rotor  12  mounting buckets or blades  14  for rotation about the axis of the compressor and stator vanes  16  fixed to the upper casing half  18 . Buckets, blades and/or vanes can be referred to as airfoils, and the term airfoil can be defined to include rotating or stationary, buckets, blades, and/or vanes. It will be appreciated that the blades  14  of the rotor are circumferentially spaced one from the other about the rotor axis and that the stator vanes  16  are similarly circumferentially spaced one from the other about the axis. The vanes and buckets form various stages of the compressor. For example, the vanes  20  and buckets  22  constitute compressor stage S 0  while the vanes  24  and buckets  26  constitute stage S 1 . Inlet guide vanes  28  are also illustrated in  FIG. 1 . 
         [0018]    Referring to.  FIG. 2 , there is schematically illustrated the stator vanes  20  of stage S 0  and the stator vanes  24  of stage S 1 . The buckets  22  mounted on the rotor  12  are illustrated disposed between the stator vanes  20  and  24 . The stator vanes  20  and  24  as well as stator vanes of other stages are typically attached to the upper and lower casing halves, schematically illustrated at  30  and  32  respectively in  FIGS. 3 and 4 . The upper and lower halves of the compressor casing may be secured at the horizontal midline to one another by bolted flanges  34  which enable the upper half  30  of the casing to be removed from the lower half  32  with the rotor (not shown) retained in the lower half. The upper and lower halves of the stator vanes  20  and  24  illustrated in  FIG. 2  are shown separated from one another for clarity. 
         [0019]    Compressors and their associated components may need to be repaired or upgraded during their service life. In some applications it may be desired to replace stator vanes with vanes having a new shape or profile and/or grouping configuration. Some known processes currently require the removal of the rotor, which significantly increases outage duration and cost. An apparatus, according to aspects of the present invention, utilizes an iterative process for removing single stator blades with the rotor in place. This in-situ process greatly facilitates upgrading or repairing the compressor as the previous known method required removing the rotor. 
         [0020]      FIG. 5  illustrates a cross-sectional view of an apparatus, according to aspects of the present invention, that can be used to remove a compressor stator vane. The tool  500  may be designed to utilize the hook fit area where the blades reside to locate the tool during use. The hook fit  505  or “T” slot is an area of the compressor case that is designed to guide and hold the stator vanes  590  or stationary components in their relative position in the compressor. The hook fits  505  can be an array or series of circumferential grooves disposed on the inward surface of the compressor case, and span the various stages of the compressor. This hook fit can vary in size in different portions of the compressor, and may be designed to accommodate segmented as well as single blades. The hook fit positions the stationary components both axially and radially for correct positioning relative to the rotating blades found on the rotor. 
         [0021]    The tool  500  is a combination of several components assembled to vibrate and extract the single blades. The tool is made up of a vibrator  520 , pneumatic cylinder  530 , jaws  515  (e.g., left hand and right hand) all mounted on a skid  535 . The skid  535  includes pins  537  that fit into and slide along a portion of the blade hook fit  505 . Air supply lines (not shown), which may use/transport compressed air, can be used to power the tool  500 . A bracket  540  can be used to retain the cables and hoses used to control and/or power the tool  500 . The vibrator  520 , may include power supply connections  522 ,  524  for connection of any appropriate power source. For example, compressed air supply lines (not shown), can be connected to connections  522 ,  524 . Alternatively, any other suitable power source could also be used (e.g., electrical power supply lines, battery power, etc.) to power the vibrator  520  or other elements of tool  500 . 
         [0022]    A blade tip pushing device  550  is attached to the skid  535  via a bracket  555 . The tip pushing device  550  may be powered by compressed air, electric motor or any other suitable means. The device  550  includes a moveable plunger  551  having a blade contact element  552 . The tip pushing device can be used to rock the blade  590  (shown in phantom) back and forth, or push it to stay in contact with the blade  590 . An additional base contact point  560  (e.g., a bolt head) may also be used to contact the base portion of blade  590 . As can be seen, the present invention provides a device having multiple blade contact points (e.g., the jaws  515 , blade contact element  552 , base contact point  560 ) and enables a blade or vane  590  to be removed in an improved manner compared to known removal techniques. In other embodiments of the present invention, multiple blades or groups of blades may be removed with tool  500 . 
         [0023]      FIG. 6  illustrates a perspective view of the tool  500  grasping a blade  590 , and a portion of the hook fit slot  505  in a compressor case. The tool  500  may also be equipped with a control device (not shown), to control and actuate the clamping action of the jaws  515 , to control the vibrator  520  and/or tip pushing device  550 . The control device may include computerized control or manual control devices. 
         [0024]      FIG. 7  illustrates the short and long metal extensions  710  that may be linked together with pins  715  or other suitable fasteners/couplings to allow for the needed length to reach the various blades in the compressor. A handle  720  may be provided that can be adjusted by loosening or tightening the handle clamp  730  to fit the position an operator, machine or machine attachment. The metal extensions  710  and handle  720  may be straight, curved or combinations thereof as desired for the specific application. An additional feature of the tool  500  is that it may be equipped with a mechanical jack (not shown), or other pulling device to provide additional pulling force as necessary for severely stuck or hard to move vanes or blades. 
         [0025]      FIG. 8  illustrates a power and control system that may be used with tool  500 . A power source or supply  810  is connected to tool  500  via connection lines  830 . The power supply may include electrical power (e.g., AC and/or DC power), pneumatic power (e.g., compressed air), hydraulic power or any other suitable power source. The connection lines  830  may be any suitable device for the transmission of the power (e.g., conductive cables/wires, compressed air hoses/lines, etc.). A control system may be used to control and/or actuate the power supply  810  and/or tool  500 , and may comprise computer control devices or manual control devices). In one example, the control device could be a laptop computer having a graphic interface allowing an operator to control the removal process. In another example, the control device may be a simple set of manually operated switches or levers that activate or deactivate various features of the power supply  810  and/or tool  500 . The control system  820  may be connected to the power source  810  and/or the tool  500  via any suitable communication medium (e.g., wired or wireless communication lines, cables, etc.) 
         [0026]    The apparatus or tool  500  is moved into place by sliding down the hook fit until it engages a stator blade. The tool&#39;s jaws  515  are actuated and the blade is captured in the jaws  515 . The vibrator  520  is turned on to provide a vibrating action to the blade being extracted. Alternatively, a peening apparatus or peening gun can be used in place of vibrator  520 . At this point the operator pulls on the handle  720 , attached to the tool  500  via extensions  710 , and pulls the stator blade toward the horizontal joint of the compressor case where it is removed from the compressor. This process is repeated until all, or the desired number of, blades have been removed from the compressor. The tool may be used with any dynamoelectric machine, including, but not limited to compressors, gas turbines or steam turbines. 
         [0027]    It will be appreciated that the removal of the upper casing half of the compressor to add, repair or upgrade additional stator vanes does not require the removal of the rotor from the lower casing half. This enables the compressor to be modified in the field or in situ. 
         [0028]    While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.