Abstract:
A method for masking at least one turbine engine component wherein the method includes providing at least one masking member, securing each masking member to the at least one turbine engine component, and applying a metal coating to the at least one turbine engine component.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    This invention relates generally to turbine engines, and, more particularly, to methods and apparatus for manufacturing turbine engine components.  
           [0002]    Known turbine engines include a compressor for compressing air which is suitably mixed with a fuel and channeled to a combustor wherein the mixture is ignited for generating hot combustion gases. The gases are channeled to a turbine, which extracts energy from the combustion gases for powering the compressor, as well as producing useful work for propelling an aircraft in flight and for powering a load, such as an electrical generator.  
           [0003]    To shield components from the high temperatures generated within the engine, at least some known components exposed to the gas flow path are coated with a metal coating, such as a thermal barrier coating (TBC). More specifically, thermal barrier coating is typically applied with a spraying process, and often only after the components have been grit blasted. However, the application of thermal barrier coating may actually adversely affect or limit the performance of some components exposed to the gas flow path, such as, for example, seal teeth used with rotating seal assemblies.  
           [0004]    To ensure that metal coating is not applied to such components, at least some spraying processes require that such components are masked prior to the metal coating being applied, and then unmasked after the metal coating has been applied. More specifically, such components are typically masked using a durable adhesive-backed tape, such as glass-filled masking tape. However, such a process may be a time-consuming and labor-intensive task. Furthermore, generally the tape is not reusable after being removed from the components.  
         BRIEF DESCRIPTION OF THE INVENTION  
         [0005]    In one aspect, a method for assembling at least one turbine engine component including a plurality of seal teeth is provided. The method comprises coupling a masking member to the at least one turbine engine component such that the masking member extends between adjacent seal teeth, applying a metal coating to the at least one turbine engine component, such that the masking member prevents contact between a portion of the plurality of seal teeth and the metal coating, and removing the masking member from the at least one engine component.  
           [0006]    In another aspect of the invention, a method for decreasing a heat induced to a turbine engine component is provided. The turbine engine includes a plurality of seal teeth separated by at least one channel. The method comprises positioning a masking member within the at least one channel such that the masking member extends in substantial sealing contact across the channel and between the seal teeth, and applying a metal coating to the at least one turbine engine component, such that the masking member prevents contact between a portion of the plurality of seal teeth and the metal coating.  
           [0007]    In a further aspect, a method for applying a metal coating to a turbine engine is provided. The method comprises coupling a masking member to at least one turbine engine component that includes a plurality of seal teeth, such that the masking member extends through a channel defined between adjacent seal teeth, and applying a metal coating within the turbine engine such that the masking member prevents contact between the seal teeth channel and the metal coating. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    [0008]FIG. 1 is schematic illustration of a gas turbine engine;  
         [0009]    [0009]FIG. 2 is a cross-sectional illustration of an exemplary seal that may be used with the gas turbine engine shown in FIG. 1;  
         [0010]    [0010]FIG. 3 is a partial perspective view of the seal shown in FIG. 2 including an exemplary masking member coupled thereto; and  
         [0011]    [0011]FIG. 4 is a partial perspective view of an exemplary masking member that may be used with the seal shown in FIG. 3. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0012]    [0012]FIG. 1 is a schematic illustration of a gas turbine engine  10  including a low pressure compressor  12 , a high pressure compressor  14 , and a combustor  16 . Engine  10  also includes a high pressure turbine  18  and a low pressure turbine  20 . Compressor  12  and turbine  20  are coupled by a first shaft  24 , and compressor  14  and turbine  18  are coupled by a second shaft  26 . In one embodiment, the gas turbine engine is a GE90 available from General Electric Company, Cincinnati, Ohio.  
         [0013]    In operation, air flows through low pressure compressor  12  and compressed air is supplied from low pressure compressor  12  to high pressure compressor  14 . The highly compressed air is delivered to combustor  16 . Airflow from combustor  16  drives turbines  18  and  20  before exiting gas turbine engine  10 .  
         [0014]    [0014]FIG. 2 is a cross-sectional illustration of an exemplary known seal  30  that may be used with gas turbine engine  10 . FIG. 3 is a partial perspective view of seal  30  including an exemplary masking member  31  coupled thereto. FIG. 4 is a partial perspective view of masking member  31 . Seal  30  includes a plurality of seal teeth  32  that extend radially outwardly from a seal body  34 . Seal teeth  32  are arranged in axially-spaced rows  36  that extend circumferentially within engine  10 . In the exemplary embodiment, seal  30  includes three rows  36  of annular seal teeth  32 .  
         [0015]    A channel  40  is formed between adjacent seal teeth  32 . More specifically, channel  40  has a depth  42  measured from a tip  44  of seal teeth  32  to a radially inner surface  46  of channel  40 , and has a width  50  measured between adjacent seal teeth sidewalls  52 . In the exemplary embodiment, channel  40  has a substantially U-shaped cross-sectional profile. In one embodiment, seal  30  is a forward outer seal. In another embodiment, seal  30  is a compressor discharge pressure seal. Alternatively, seal  30  is any seal including at least one channel defined between adjacent seal teeth.  
         [0016]    In the exemplary embodiment, masking member  31  includes a body  58  including a radially inner wall  60  and an oppositely-disposed radially outer wall  62  that are connected by a pair of oppositely-disposed sidewalls  64  and  66  and by a pair of radial edges  68  and  70 . Sidewalls  64  and  66  define ends for masking member  31  and a length  72  of masking member  31  is measured between sidewalls  64  and  66 . Masking member length  72  is variably selected depending on the seal member  30  being masked, and such that length  72  is slightly shorter than a circumferential length defined by seal channel  40 .  
         [0017]    A width  80  of masking member  31  is measured between sidewalls  68  and  70 . Masking member width  80  is variably selected depending on a seal channel width  50  of a seal  30  being masked. More specifically, masking member width  80  is substantially equal to, or slightly larger than, a width of channel  40 . A thickness  86  of masking member  31  is measured between walls  60  and  62 , and is variably selected depending on a depth  42  seal  30  being masked.  
         [0018]    A cross-sectional shape of body  58  is variably depending on a seal  30  being masked. More specifically, as described in more detail below, a shape of body  58  is selected to facilitate substantially scaling channel  40 . For example, in one embodiment, body  58  is substantially semi-circular. In another embodiment, is substantially semi-elliptical. Although masking member  31  is herein described and illustrated in the exemplary manner, it should be understood that the particular geometry and cross-sectional shape of member  31 , will vary depending on the particular configuration and geometrical shape of seal  30 . The embodiment illustrated is intended as exemplary, and is not intended to limit the geometry and cross-sectional shape of member  31  or seal  30 .  
         [0019]    Masking member  31  is fabricated material that enables member  31  to be flexible and stretchable along length  72 . For example, in the exemplary embodiment, masking member  31  is fabricated from extruded silicone rubber. The extruded silicone rubber is then cut to a desired length  72 .  
         [0020]    To shield engine components from high temperature generated therein, components exposed to the high temperatures may be coated with a metal coating, such as but not limited to thermal barrier coating (TBC). The metal coating may either facilitate reducing heat transfer into the components, which may permit the engine to operate with an increased operating temperature for increasing an efficiency of the engine, and/or providing wear resistance to the components being coated. As described in more detail below, masking member  31  prevents an undesirable build-up of metal coating from forming within seal channel  40  as the metal coating is applied to components adjacent seal  30 .  
         [0021]    Specifically, before the metal coating is applied, and before any components adjacent seal  30  are grit-blasted, masking member  31  is coupled to seal  30  to facilitate preventing at least a portion of seal  30  from being grit blasted and/or sprayed with metal coating. More specifically, initially a desired length  72  of masking member  31  is cut from an extruded length of masking member material. Masking member  31  is then inserted within a desired seal channel  40  to be shielded. Because member  31  is pliable, and because seal channel  40  may be tapered, masking member  31  may be forcibly inserted within channel  40  such that masking member  31  extends across channel  40  and is substantially flush against at least a portion of each adjacent seal tooth sidewall  52 . In one embodiment, a sealant is applied to channel  40  before masking member  31  is inserted within channel  40 . In one embodiment, the sealant is a silicone rubber commercially available from Shercon, Inc., Santa Fe Springs, Calif. In another embodiment, the sealant is a silicone rubber commercially available from Cynflex, Ltd, Nottinghamshire, U.K.  
         [0022]    Masking member  31  is then stretched circumferentially around channel  40  such that masking member first end  64  is adjacent masking member second end  66 . First end  64  is then coupled to second end  66 . In one embodiment, heating the sealant facilitates coupling the first and second ends  64  and  66 , respectively, together. In another embodiment, a vulcanizing process is used to couple first end  64  to second end  66 . In a further embodiment, a molding process is used to couple first end  64  to second end  66 . Stretching masking member  31  facilitates forcing masking member  31  radially inwardly towards channel inner surface  46  such that sealing member body  58  is plastically deformed against seal teeth  32  and in sealing contact with seal teeth sidewalls  52 .  
         [0023]    A metal coating is then applied through spraying to the engine components adjacent seal  30 . In one embodiment, the metal coating is a thermal coating such as, but not limited to, thermal barrier coating (TBC). In another embodiment, the metal coating is a wear-resistant coating. Masking member  31  facilitates preventing contact between seal channel  40  and the thermal barrier coating, and thus prevents the metal coating from being undesirably deposited within channel  40 . Furthermore, if seal  30  or any engine component are grit blasted, masking member  31  facilitates shielding channel  40  from the abrasive material sprayed during the grit blasting. In addition, because masking member  31  is pliable, following the application of the metal coating, or the application of the grit blasting, masking member  31  is removed and may be reused. More specifically, once removed, masking member  31  returns to its original shape.  
         [0024]    The above-described methods for manufacturing engine components are cost-effective and highly reliable. More specifically, the masking member allows a plurality of seal configurations to be quickly masked in an efficient and timely manner, resulting in reduced manufacturing costs. Furthermore, the masking member facilitates improving the quality and repeatability of the masking of components in a cost-effective and reliable manner.  
         [0025]    Exemplary embodiments of seal assemblies and masking members are described above in detail. The assemblies and members are not limited to the specific embodiments described herein, but rather, components of each assembly may be utilized independently and separately from other components described herein. Each masking member can also be used in combination with other seal assembly components.  
         [0026]    While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.