Abstract:
A brush seal for installation in an apparatus having features for securing the brush seal, the brush seal comprising: a side plate; a back plate; and a bristle arrangement secured between the side plate and the back plate. The features of the apparatus act as the side plate and the back plate of the brush seal. A method of installing a brush seal in an apparatus, comprising the steps of: providing an apparatus with features for securing the brush seal thereto; providing a bristle arrangement; and securing the bristle arrangement to the features. The features act as a back plate and a side plate for the bristle arrangement.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application is related to U.S. patent application No. 10/074,191, filed on Feb. 12, 2002 and herein incorporated by reference. 
     
    
     
       BACKGROUND OF INVENTION  
         [0002]    This invention relates to a brush seals. Specifically, this invention relates to a brush seal for an apparatus that utilizes features of the apparatus as functioning elements of the brush seal. This enables the brush seal to have fewer parts.  
           [0003]    Brush seals prevent the escape of fluid (i.e. air) through a gap between two parts of an apparatus. One such apparatus that uses brush seals is a gas turbine engine. The placement of the brush seal in the engine typically prevents secondary flow from escaping through a gap between a stationary part ( e.g. a diffuser case) and a rotating part ( e.g. a turbine shaft). The brush seal can have other uses, such as sealing a gap between stationary parts of the engine.  
           [0004]    The brush seal mounts to a support and a removable retainer on the engine.  
           [0005]    Specifically, the brush seal mounts against the support and the removable retainer confines the brush seal against the support. The support typically engages a side of a conventional brush seal and the retainer typically engages a back plate of a conventional brush seal.  
           [0006]    Of the numerous parts involved in this arrangement of a conventional brush seal, some of the parts have redundancy with other parts. This redundancy could impact the weight, cost and complexity of the brush seal arrangement.  
         SUMMARY OF INVENTION  
         [0007]    It is an object of the present invention to provide a brush seal with a reduced part count.  
           [0008]    It is a further object of the present invention to reduce inventory costs.  
           [0009]    It is a further object of the present invention to provide a lighter weight brush seal.  
           [0010]    It is a further object of the present invention to provide a reduced cost brush seal.  
           [0011]    It is a further object of the present invention to manufacture a brush seal assembly in fewer steps.  
           [0012]    It is a further object of the present invention to assemble a brush seal with simpler fixturing.  
           [0013]    It is a further object of the present invention to provide a brush seal assembly method that allows easier inspection.  
           [0014]    It is a further object of the present invention to provide a brush seal assembly with reusable parts.  
           [0015]    It is a further object of the present invention to reduce the cost of replacing a brush on an apparatus.  
           [0016]    These and other objects of the present invention are achieved in one aspect by a brush seal for installation in an apparatus having features for securing said brush The brush seal includes: a side plate; a back plate; and a bristle arrangement secured between the plate and back plate. The features of the apparatus act as the side plate and the back plate of the brush seal.  
           [0017]    These and other objects of the present invention are achieved in another aspect by a method of installing a brush seal in an apparatus. The method comprises the steps of: providing an apparatus with features for securing the brush seal thereto; providing a bristle arrangement; and securing the bristle arrangement to the features. The features act as a back plate and a side plate for the bristle arrangement.  
           [0018]    These and other objects of the present invention are achieved in another aspect by an apparatus having features for securing a brush seal thereto. The improvement comprises the features acting as a back plate and a side plate of the brush seal. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0019]    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:  
         [0020]    [0020]FIG. 1 is a partial cross-sectional view of a conventional multiple stage brush seal installed in an apparatus;  
         [0021]    [0021]FIG. 2 is a partial cross-sectional view of one embodiment of a brush seal of the present invention installed in an apparatus;  
         [0022]    [0022]FIG. 3 is a cross-sectional view of the brush seal of FIG. 2 before installation in an apparatus;  
         [0023]    [0023]FIG. 4 is a partial elevational view of one component of the brush seal of FIG. 3;  
         [0024]    [0024]FIG. 5 is a cross-sectional view of the component of FIG. 4 taken along line V-V; and  
         [0025]    [0025]FIG. 6 is a partial cross-sectional view of another embodiment of a brush seal of the present invention installed in an apparatus. 
     
    
     DETAILED DESCRIPTION  
       [0026]    [0026]FIG. 1 provides a partial cross-sectional view of a conventional apparatus  50  having a brush seal  51 . The apparatus  50  is preferably a gas turbine engine, but could be any other suitable machine. The brush seal  51  prevents secondary fluid flow from escaping through a gap between a first, typically stationary, part  53  ( e.g. a diffuser case of a gas turbine engine) and a second, typically rotating, part  55  ( e.g. a turbine shaft of a gas turbine engine).  
         [0027]    The brush seal  51  includes a side plate  57  (with an integral windage cover), a middle plate  59  and a back plate  61 . Bristle packs  63  reside between the plates  57 ,  59 ,  61 . The plates  57 ,  59 ,  61  are made from suitable alloys, such as Inconel® or 400-series stainless steel. The bristles are also made from a suitable alloy such as a cobalt alloy. The plates  57 ,  59 ,  61  and the bristle packs  63  are welded together to form an assembly before placement in the engine  50 .  
         [0028]    The brush seal  51  removably mounts to the engine  50 . The engine  50  includes a support  65 , such as an annular flange, and a removable retainer  67  for mounting the brush seal  51 . As a first assembly step, the technician places the brush seal  51  against the support  65  in the engine  50 .  
         [0029]    The technician then places the removable retainer  67  against the brush seal  51 . Finally, the technician secures the retainer  67  to the engine  50  using suitable fasteners  69  such as rivets. The support  65  and the retainer  67  sandwich the brush seal  51  in proper position within the engine  50 .  
         [0030]    During operation, the bristle packs  63  extend from the diffuser case  53  and engage the turbine shaft  55 . In other words, the bristle packs  63  seal a gap between the diffuser case  53  and the turbine shaft  55  to prevent the escape of secondary fluid flow.  
         [0031]    [0031]FIG. 2 provides a partial cross-sectional view of an apparatus  100  having a brush seal  101  of the present invention. As with apparatus  50 , the apparatus  100  could be a gas turbine engine or other suitable machine. The brush seal  101  likewise prevents secondary fluid flow from escaping through a gap between a first part  103  ( e.g. a diffuser case of a gas turbine engine) and a second part  105  ( e.g. a turbine shaft of a gas turbine engine).  
         [0032]    The brush seal  101  removably mounts to the engine  100  using a support  107 , such as an annular flange, and a removable retainer  109 . As with the conventional brush seal  51 , the retainer  109  secures to the engine  100  using suitable fasteners  111  such as rivets, snap rings (not shown), threaded fasteners (not shown) and retaining rings (not shown). Alternatively, the retainer  109  could be welded or brazed to the engine  100 . When fastened to the engine  100 , the retainer  109  sandwiches the brush seal  101  against the support  107  for proper positioning of the brush seal  101  within the engine  100 .  
         [0033]    Differently than the conventional brush seal  51 , the support  107  and the retainer  109  act as the side plate and the back plate of the brush seal  101  of the present invention. The use of the support  107  and the retainer  109  as the side plate and the back plate has clear benefits. For example, the brush seal  101  has fewer parts than the conventional brush seal  51 . With fewer parts, the brush seal  101  should reduce the weight of the engine  100 , lower inventory costs, and have a lower manufacturing cost. Lacking the side plate and the back plate, the present invention can assemble the brush seal  101  in fewer steps than with the conventional brush seal  51 . For example, the conventional brush seal  51  requires the side plate and back plate to undergo a facing operation during assembly. The brush seal of the present invention does not.  
         [0034]    Although FIG. 2 shows an engine configuration with the support  107  and the retainer  109  acting as the back plate and side plate, respectively, the engine could have a different configuration (not shown) with the support  107  and the retainer  109  acting as the side plate and back plate, respectively.  
         [0035]    To act as the side plate and back plate of the brush, the support  107  and the retainer  109  should have a different shape than the support  65  and retainer  67  of the conventional arrangement. Specifically, the support  107  and the retainer  109  should be radially lengthened and should approximate the shape of the side plate  57  (with the integral windage cover) and back plate  61  at locations adjacent the brush seal  101 . In an Original Equipment Manufacturer (OEM) situation, the support  107  and the retainer  109  could be manufactured to the new shape. In a post-OEM ( e.g. repair) situation, the support  107  and the retainer  109  could have extra material added thereto such as by welding.  
         [0036]    Likewise, the brush seal  101  is different from the conventional brush seal  51 . FIG. 3 displays brush seal  101  before installation in the engine  100 . The brush seal includes bristle arrangements  113  separated by a mid plate  115 . Notably, the brush seal  101  lacks a side plate and a back plate. As discussed above, the support  107  and the retainer  109  of the engine  100  act as the side plate and back plate when the brush seal is installed in the engine  100 .  
         [0037]    [0037]FIGS. 4 and 5 show the bristle arrangement  113  for the brush seal of the present invention. Although the figure only shows an arcuate segment, the bristle arrangement  113  is preferably annular. In an annular configuration, the bristle arrangement  113  can be referred to as a bristle ring.  
         [0038]    The bristle ring  113  includes a plurality of bristles  117  made from a suitable alloy such as a cobalt alloy. An annular joint  119  secures the bristles together. Preferably, the joint  119  is a weld joint. U.S. patent application No. 10/074,191 describes in further detail the steps involved in making the bristle ring  113 . As seen in FIG. 4, the bristles  117  are not aligned with a radial line of the bristle ring  113 . Rather, the bristles  117  form a lay angle (in the direction of rotation of the turbine shaft  105 ) with the radial line of the bristle ring  113 .  
         [0039]    The mid plate  115  for the brush seal  101  of the present invention can be identical to the mid plate  51  for the conventional brush seal  51 . As with the plates of the conventional brush seal  51 , the mid plate  115  can be made from a suitable alloy, such as Inconel® or 400-series stainless steel.  
         [0040]    The technician assembles the brush seal  101  by first placing one bristle ring  113  within a fixture (not shown). The technician then places the mid plate  115  into the fixture, followed by the second bristle ring  113 . The technician then secures another fixture (not shown) to the first fixture for holding the bristle rings  113  and mid plate  115  together temporarily. The fixturing used assemble the bristle ring  113  is simpler than the fixturing used to assemble the conventional brush seal  51 . The conventional brush seal fixturing is more complex since the fixturing must accommodate the side plate and the back plate. The fixturing for the present invention does not require these complexities since the brush seal  101  has neither a side plate nor a back plate.  
         [0041]    The technician secures the bristle rings  113  and mid plate  115  together using a suitable technique such as by welding. The technician can then disconnect the fixturing to reveal the fully assembled brush seal  101  of the present invention.  
         [0042]    Lacking the side plate and the back plate, inspection of the brush seal  101  of the present invention is easier than with conventional brush seals  51 . Inspecting the conventional brush seal  51  is more difficult because the side plates and back plate obscure portions of the weld joint.  
         [0043]    Since the brush seal  101  lacks a side plate and a back plate, the present invention modifies the support  107  and the retainer  109  to act as the side plate and the back plate. Specifically, the support  107  is radially lengthened. As with the back plate  61  of the conventional brush seal  51 , the lengthened support  107  engages a substantial length of the bristles  117  to limit bristle blowover in the flow direction. The support  107  could be lengthened by, for example, welding additional material thereto.  
         [0044]    Since the retainer  109  is removable, the present invention can either can either radially lengthen the retainer  109  similar to the support  109 , or the present invention can use a replacement retainer  109  that made to-length. As with the side plate  57  of the conventional brush seal, the proximal ( i.e. radially outer) end of the retainer  109  abuts the bristles  113 . The distal ( i.e. radially inner) end of the retainer is laterally spaced from the bristles  113  to act as the windage cover.  
         [0045]    Replacement of the brush seal  101  of the present invention should be less expensive than the replacement of the conventional brush seal  51 . When replacing the conventional brush seal  51 , the technician removes the rivets  69  to release the retainer  67 , removes the brush seal  51  (including the side plate, back plate and bristle packs), provides a replacement brush seal (with side plate, back plate and bristle packs) and resecures the retainer  67 . When replacing the brush seal  101  of the present invention, the technician only needs to remove the rivets  111  to release the retainer  109 , remove the bristle ring  113 , replace the bristle ring  113  and reattach the retainer  109 . In essence (since the side plate and back plate are engine part not part of the brush seal  101 ), the present invention reuses the side plate and the back plate of the brush seal.  
         [0046]    Although FIG. 2 displays a multiple stage brush seal  101 , the present invention could also be used on a single stage brush seal. FIG. 6 displays an engine  200  with such a single stage brush seal  201 . In the single stage version, the brush seal  201  comprises just a bristle ring  213 . As with the multiple stage version, a support  207  and a retainer  209  of the engine  200  act as the side plate and the back plate of the brush seal  201 .  
         [0047]    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.