Abstract:
A cleaning preparation method, comprising: providing a part with an internal cavity, an opening, and foreign material within the cavity; and creating an additional opening in the part adjacent the foreign material. A cleaning method, comprising: providing a part with an internal cavity and an opening; creating an additional opening in the part; and flushing the cavity with a fluid. The additional opening acts as an exit or entrance for the fluid. A repair method, comprising: providing a part with an internal cavity, an opening and foreign material within the cavity; creating an additional opening in the part; and removing the foreign material through the additional opening. A part, comprising: an exterior surface; an internal cavity; an opening through the surface to the cavity; and a repaired section of the surface, which was an additional opening that provided a temporary exit or entrance to the cavity for foreign material removal.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     This invention relates to methods of preparing, cleaning and repairing an article an the repaired article.  
       BRIEF SUMMARY OF THE INVENTION  
       [0002]     It is an object of the present invention to provide a method of preparing an article for cleaning.  
         [0003]     It is a further object of the present invention to provide a method of cleaning an article.  
         [0004]     It is a further object of the present invention to provide a method of repairing an article.  
         [0005]     It is a further object of the present invention to provide a repaired article.  
         [0006]     These and other objects of the present invention are achieved in one aspect by a method of preparing a part for cleaning, comprising the steps of: providing a part with an internal cavity, at least one opening in communication with the cavity, and foreign material within the cavity; and creating an additional opening in the part at a location adjacent the foreign material.  
         [0007]     These and other objects of the present invention are achieved in another aspect by method of cleaning a part, comprising the steps of: providing a part with an internal cavity, at least one opening in communication with the cavity; creating an additional opening in the part; and flushing the cavity with a fluid. The additional opening acts as an exit or entrance for the fluid.  
         [0008]     These and other objects of the present invention are achieved in another aspect by a method of repairing a part, comprising the steps of: providing a part with an internal cavity, at least one opening in communication with the cavity, and foreign material within the cavity; creating an additional opening in the part; and removing the foreign material. The removing step occurs through the additional opening.  
         [0009]     These and other objects of the present invention are achieved in another aspect a part, comprising: an exterior surface; an internal cavity; at least one opening through the surface and in communication with the cavity; and a repaired section of the surface. The repaired section was an additional opening that provided a temporary exit or entrance to the cavity for removing foreign material from the cavity. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]     Other uses and advantages of the present invention will become apparent to those skilled in the art upon reference to the specification and the drawings, in which:  
         [0011]      FIG. 1  is a cross-sectional view of a gas turbine engine;  
         [0012]      FIG. 2  is an elevational view of a turbine blade used in the engine of  FIG. 1 ;  
         [0013]      FIG. 3  is a cross-sectional view of the turbine blade of  FIG. 2 ;  
         [0014]      FIG. 4  is the turbine blade of  FIG. 3  showing the presence of foreign material therein;  
         [0015]      FIG. 5  is the turbine blade of  FIG. 3  after a step in one possible method of removing the foreign material;  
         [0016]      FIG. 6  is the turbine blade of  FIG. 3  during another step of one possible method of removing the foreign material; and  
         [0017]      FIG. 7  is the turbine blade of  FIG. 3  after being refurbished by one possible method of removing the foreign material. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0018]      FIG. 1  displays a gas turbine engine  10  used, for example, for propulsion or power generation. Along an axial centerline  12  in the downstream direction, the engine  10  includes a fan section  14 , a compressor section  16 , a burner section  18  and a turbine section  20 .  
         [0019]     The fan section  14  draws air  22  into the engine  10 . A portion of the air  22  drawn in by the fan section  14  travels into the compressor  16  (i.e. “core engine flow”), while the remainder (i.e. “bypass flow”) does not. The core engine flow becomes compressed traveling through the compressor section  16 , then mixes with fuel supplied by fuel injectors in the burner section  18 . Within the burner section  18 , the air/fuel mixture combusts. The combustion gases exit the burner section  18  and enter the turbine section  20 . The combustion gases drive the turbine section  18 .  
         [0020]      FIG. 2  displays a portion of the turbine section  20 . Specifically, the figure displays a turbine blade  22  with a root section  26  and an airfoil section  28  separated by a platform  30 . The root section  26  secures to a correspondingly shaped feature on a rotor  32  (shown in phantom). Since the platform  30 , in combination with other features of the engine  10 , defines the radially inner boundary of the core gas path, the airfoil section  28  resides within the core gas path. The engine case  34  (shown in phantom) defines the radially outer boundary of the core gas path. During operation, the rotor  32  and turbine blades  22  spin as a result of the combustion gases CG exiting the burner section  18 .  
         [0021]     So the turbine section  20 , particularly the airfoil section  28  of the turbine blades  28 , can endure prolonged exposure to the high temperature of the combustion gases CG, the engine  10  introduces cooling air to the turbine section  20 . Typically, the engine  10  draws such cooling air from the compressor section  16 . One path for introducing cooling air to the turbine section  20  is through the turbine blades  22 . As explained in more detail below, the turbine blade  22  is hollow so as to receive cooling air CA.  
         [0022]      FIG. 3  displays a cross-sectional view of the turbine blade  22 . The turbine blade  22  has an internal cavity  36 . The cavity  36  includes one or more openings, such as one or more inlets  38  and one or more outlets  40 . In addition to the exterior surface  42 , the turbine blade  22  could include one or more internal walls  44  arranged to form a serpentine passageway  46  between the inlets  38  and outlets  40 . The cooling air CA can enter the internal cavity  36  through the inlets  38 , travel along the passageway  46 , then exit the outlets  40 . Although shown in the figure as disposed along the trailing edge, the outlets  40  could reside anywhere on the airfoil section  28  and in any desired arrangement.  
         [0023]     As seen in  FIG. 4 , foreign material F can become trapped within the cavity  36 . Various causes can introduce the foreign material F to the cavity  36 . For instance, harsh operating conditions can introduce the foreign material F (e.g. sand) into the engine  10 . In addition, maintenance operations (e.g. coating removal) can introduce the foreign material F to the cavity  36 . In fact, the manufacturing process that produces the turbine blade  22  could introduce the foreign material F. Although shown at one specific location within the cavity  36 , the foreign material F could reside at any location within the cavity  36 .  
         [0024]     The presence of the foreign material F within the cavity  36  can reduce the effectiveness of the cooling air CA. Unless successful removal of the foreign material F occurs, the turbine blade  22  will likely not return to service (i.e. scrapped). Scrapping a turbine blade  22  can be costly. Removal of the foreign material F from the cavity  36  can prove difficult for several reasons. First, the operation of the engine  22  with the foreign material F present, the performance of maintenance operations and the manufacturing processes tend to sinter the foreign material F in place. Second, the typical size of the inlets  38  and outlets  40  and the shape of the serpentine passageway  46  make access to the foreign material F difficult.  
         [0025]     The following describes the steps in one possible method of refurbishing the turbine blade  22  by removing the foreign material F. Although described with specific reference to a turbine blade, the methods described herein have applicability with any part having an internal cavity that may contain foreign material F. These parts could be other parts of the engine  10 , such as turbine vanes, or parts unrelated to gas turbine engines.  
         [0026]     One step in a possible method of removing the foreign material F is to locate the foreign material F within the cavity  36 . Depending on the position of the foreign material F within the serpentine passageway  46 , various techniques are available to locate the foreign material. For example, the technician may visually identify the location of the foreign material F. Most likely, however, the technician would need to rely on suitable machines to locate the foreign material F. For instance, the technician could use x-ray, neutron radiography, ultrasound and thermal imaging to locate the foreign material F.  
         [0027]     Another step in a possible method of removing the foreign material F is to create another opening in the turbine blade  22 .  FIG. 5  shows the turbine blade  22  with an additional opening  48  in communication with the cavity  36 . The technician could rely on any suitable technique to create the additional opening  48  in the turbine blade  22 . For example, a technician could utilize a router, milling machines, electrical discharge machining (EDM) or laser drilling to create the additional opening  48 . As seen in the figure, the additional opening  48  could have the shape of a channel on the tip of the turbine blade  22 , transversing the turbine blade  22  from a concave side to a convex side of the airfoil section  28 , but other shapes are possible. The figure also shows the opening  48  extending in the radial direction, but other orientations (e.g. angled relative to the radial direction) are possible.  
         [0028]     Furthermore, the additional opening  48  could have any suitable position on the turbine blade  22 . The position of the additional opening  48  could be selected relative to the location of the foreign material F and to the specific techniques used in later method steps. Generally speaking, one suitable location for the additional opening  48  is radially outboard of the foreign material F and as close to the foreign material F as possible. As seen in the figure, the additional opening  48  is downstream of the foreign material F.  
         [0029]     Performing the locating step is not mandatory. Without the locating step, the technician does not know the exact location of foreign material or if foreign material even resides within the cavity  36 . In this instance, one suitable location for the additional opening  48  is adjacent an expected location of the foreign material F, determined either by prior experience or estimation. After adding the additional opening  48 , preparation of the turbine blade  22  has occurred. The turbine blade  22  can proceed to another step in a possible method, the removal of the foreign material F.  
         [0030]      FIG. 6  shows another step in a possible method of removing the foreign material F. The figure displays a cleaning device for the cavity  36 , such as a high-pressure washer  50 . The washer includes a fluid source  52 , a manifold  54  for receiving fluid W from the fluid source  52  and one or more probes  56  for discharging the fluid into the cavity  36 . The shape of the serpentine passageway  46  can determine the length and positioning of the probes  56  within the cavity  36 . As an example, the location of the probes  56  helps direct the fluid through the serpentine passageway  46  and out of the cavity  36 . While water appears the most economical and environmentally friendly choice to flush out the foreign material F, the washer  50  could operate with other fluids, or even with water having additives therein.  
         [0031]     The washer  50  could operate, for example, at pressures of between approximately 1000 and 20,000 psi. In addition, the washer  50  could have an automatic wash cycle or the technician could manually operate the washer  50 . As an example, the washer  50  could be a HDP52 Power Flush unit available from Hammelmann Corporation of Dayton, Ohio.  
         [0032]     Although shown in  FIG. 6  as entering the cavity  36  through the inlets  38 , the probes  56  could enter the cavity  36  through any suitable opening. In other words, the probes  56  could enter the cavity  36  through the outlets  40  or the additional opening  48 . That allows the additional opening  48  to either serve as an entrance for the fluid into the cavity  36  or, as seen in  FIG. 6 , as an exit for the fluid W from the cavity  36 . The technician may need to repeat the aforementioned method any number of times to remove the foreign material F entirely.  
         [0033]     Rather than using the washer  50 , the present invention could use alternate steps to dislodge the foreign material F. As one example, a technician could use an implement, such as a pick, to enter the cavity  36  and to physically contact the foreign material F. The technician could insert the implement through the additional opening  48 , although the other openings are also available. Entering the cavity  36  through the additional opening  48  may require the additional opening  48  to have a different location or shape than that described above. For example, the additional opening could be directed towards the foreign material F to assist insertion of the implement.  
         [0034]     After dislodging the foreign material, another step in a possible method is to close the additional opening  48 . The technician could use any suitable technique to close the additional opening  48 . Depending on the material used for the turbine blade  22 , suitable techniques include, for example, weld build-up, a weld plug, transient liquid phase bonding and brazing a filler material therein.  
         [0035]      FIG. 7  displays the turbine blade  22  after closing the additional opening  48 . The turbine blade  22  now has a repaired section  58  that was once the additional opening  48 . In other words, the additional opening was a temporary feature on the turbine blade  22 . Preferably, the repaired turbine blade  22  mirrors the turbine blade before the repair, except for the foreign material F. The present invention allows for the salvage of turbine blades  22  that, due to the presence of the foreign material F in the cavity  36 , would typically require scrapping.  
         [0036]     The present invention has been described in connection with the preferred embodiments of the various figures. It is to be understood that other similar embodiments may be used or modifications and additions may be made to the described embodiment for performing the same function of the present invention without deviating therefrom. Therefore, the present invention should not be limited to any single embodiment, but rather construed in breadth and scope in accordance with the recitation of the appended claims.