Abstract:
A check valve includes a valve housing and at least one control member. The valve housing includes a sidewall and an opening extending therethrough. The sidewall defines the opening and includes at least one recess formed therein. Each control member is rotatably coupled to the valve housing within the sidewall recess, and each control member is configured to allow flow of fluid through the valve opening in a first direction. Each control member is further configured to substantially prevent flow of fluid through the valve opening in a second direction that is opposite the first direction.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    This invention relates generally to gas turbine engines and more particularly, to cooling systems used to supply cooling air to gas turbine engine components.  
           [0002]    Gas turbine engines typically include cooling systems to supply cooling air to components exposed to high temperatures. For example, at least some known gas turbine engines include cooling systems which supply air to pressurized sumps. More specifically, within such engines, a pair of ducts are used to route cooling air from a compressor stage to cooling plates positioned within the sumps.  
           [0003]    During engine operation, the cooling air facilitates preventing an operating temperature of the cooling plates from increasing as a result of exposure to heat generated by the engine. The ducts may also be exposed to vibrational stresses induced by the engine during engine operation. Over time, continued exposure to the vibrational and thermal stresses may damage one of the cooling supply ducts. More specifically, such stresses may cause duct breaks. Depending on a severity of the damage to the duct, the cooling air may flow through the duct break rather than into the sump. Furthermore, because the sump is pressurized, cooling air supplied to the sump by the other duct may be exhausted from the sump through the broken duct, thus increasing an operating temperature of the cooling plates. Over time, continued exposure to the higher operating temperatures may damage the cooling plates.  
         BRIEF SUMMARY OF THE INVENTION  
         [0004]    In one aspect, a check valve is provided. The check valve includes a valve housing and at least one control member. The valve housing includes a sidewall and an opening extending therethrough. The sidewall defines the opening and includes at least one recess formed therein. Each control member is rotatably coupled to the valve housing within the sidewall recess, and each control member is configured to allow flow of fluid through the valve opening in a first direction. Each control member is further configured to substantially prevent flow of fluid through the valve opening in a second direction that is opposite the first direction.  
           [0005]    In another aspect, a method for operating a gas turbine engine is provided. The method includes directing fluid downstream from a cooling air supply duct through a check valve that includes a hollow valve housing including a sidewall that has a recess formed therein and at least one control member that is rotatably coupled to the check valve within the recess. The method also includes preventing fluid from flowing upstream into the supply duct with the check valve.  
           [0006]    In a further aspect, a gas turbine engine cooling air supply system is provided. The cooling air supply system includes a cooling air supply duct including an end, and a check valve. The check valve is coupled to the cooling air supply duct end and is configured to permit fluid flow from the cooling air supply duct while substantially preventing fluid flow into the cooling air supply duct, and includes a hollow valve housing and at least one control member. The valve housing includes a sidewall and an opening that extends therethrough. The sidewall defines the opening and includes at least one recess formed therein. The control member is rotatably coupled to the valve housing within the sidewall recess. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    [0007]FIG. 1 is a schematic illustration of a gas turbine engine;  
         [0008]    [0008]FIG. 2 is perspective view of a check valve that may be used with the engine shown in FIG. 1;  
         [0009]    [0009]FIG. 3 is a plan view of the check valve shown in FIG. 2; and  
         [0010]    [0010]FIG. 4 is a cross-sectional schematic view of the check valve shown in FIG. 2 and coupled to a cooling air supply duct. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0011]    [0011]FIG. 1 is a schematic illustration of a gas turbine engine  10  including a fan assembly  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 . Engine  10  has an intake side  28  and an exhaust side  30 . In one embodiment, engine  10  is a CF-34 engine commercially available from General Electric Aircraft Engines, Cincinnati, Ohio. Engine  10  includes a sump (not shown) which is pressurized and cooled with cooling air. In one embodiment, air is routed from a fourth stage of compressor  14  for cooling the sump.  
         [0012]    In operation, air flows through fan assembly  12  and compressed air is supplied to compressor  14 . The compressed air is delivered to combustor  16 . Airflow from combustor  16  drives turbines  18  and  20 , and turbine  20  drives fan assembly  12 .  
         [0013]    [0013]FIG. 2 is perspective view of a check valve  40  that may be used to regulate fluid flow on a gas turbine engine, such as engine  10  (shown in FIG. 1). More specifically, in one embodiment, valve  40  is utilized within a cooling air supply system (not shown in FIG. 2) to supply cooling air from a compressor, such as compressor  14  (shown in FIG. 1) to a downstream engine sump (not shown). Valve  40  is hollow and includes a housing  42  including a downstream end  44 , an upstream end  46 , and a sidewall  50  extending therebetween.  
         [0014]    Housing downstream end  44  includes an integral flange  60  which may be used to couple valve  40  to an engine component (not shown). Flange  60  extends radially outwardly from a centerline axis of symmetry  64  of valve  40 , such that flange  60  has an outer diameter  62  that is larger than an outer diameter (not shown in FIG. 2) of housing upstream end  46 . In the exemplary embodiment, flange  60  is substantially circular. Flange  60  includes a pair of stops  66  that extend radially inwardly towards centerline axis of symmetry  64 . Stops  66  are diametrically opposed and are identical.  
         [0015]    Housing upstream end  46  includes a lip  68  that is used to coupled valve  40  to a cooling supply duct or tube (not shown in FIG. 2). In the exemplary embodiment, lip  68  is substantially circular and is welded to the cooling supply duct. More specifically, lip  68  enables valve  40  to be coupled to the cooling supply duct such that an orientation of valve  40  with respect to the duct geometry is maintained.  
         [0016]    Sidewall  50  is substantially cylindrical and defines an opening  70  that extends between housing downstream and upstream end  44  and  46 , respectively. In the exemplary embodiment, at housing ends  44  and  46 , opening  70  is substantially circular, and has a diameter  72  at each end  44  and  46 . Sidewall  50  includes an interior surface  74  and an exterior surface  76 . Valve opening  70  is defined by sidewall interior surface  74 .  
         [0017]    A pair of recesses  80  are formed by sidewall  50 . Recesses  80  are identical and are diametrically opposed. In the exemplary embodiment, recesses  80  are substantially aligned with respect to flange stops  66 . Each recess  80  extends radially outwardly from valve centerline axis of symmetry  64 . In the exemplary embodiment, each recess  80  has a substantially triangular cross-sectional profile. Each recess  80  includes a pair of openings  90  that extend through sidewall  50 . More specifically, openings  90  are substantially aligned with respect to each other, and are each sized to receive a hinge pin  92  therethrough.  
         [0018]    A ledge  96  extends radially inward from sidewall  50 . More specifically, ledge  96  extends radially inward from sidewall interior surface  74 . Ledge  96  does not extend circumferentially within sidewall interior surface  74 , but rather extends arcuately between recesses  80 .  
         [0019]    A pair of control members or petals  100  are coupled to valve  40  within recesses  80 . Members  100  are identical and are rotatably coupled to valve  40  with hinge pins  92 . Accordingly, members  100  are rotatable between a fully-closed position (not shown in FIG. 2) and a fully-open position (not shown in FIG. 2). Accordingly, members  100  include a flapper portion  106  which extends across valve opening  70 , and an attachment portion  110  which extends into each respective sidewall recess  80 .  
         [0020]    Each control member portion  106  is substantially semi-circular and includes an upper surface  112  and a lower surface  114 . Members  100  are contoured and accordingly, each portion  106  is not planar. In one embodiment, each member portion  106  is substantially semi-spherical. In the exemplary embodiment, each member lower surface  114  is contoured with respect to each member upper surface  112  such that a thickness  118  of each member portion  106  remains substantially capable of withstanding operating mechanical loads. A projection  119  extends from each control member upper surface  112  for contacting a respective flange stop  66  when a respective member  100  is in the fully-open position.  
         [0021]    [0021]FIG. 3 is a plan view of check valve  40  viewed towards valve housing upstream end  46 . FIG. 4 is a cross-sectional schematic view of the check valve  40  coupled to a cooling air supply system  120 . More specifically, within FIG. 3, a control member  100  is in a fully-open position  122 , and the other control member  100  is in a fully-closed position  124 . When each control member  100  is in the fully-closed position  124 , an outer perimeter portion  126  of each member portion  106  is positioned adjacent each respective sidewall ledge  96 , and a center perimeter portion  128  extends substantially diametrically across valve opening  70 . Center perimeter portion  128  includes a tapered outer edge  130  which enables the member center perimeter portions  128  of each respective member portion  106  to mate substantially flush against each other when members  100  are in the fully-closed position  124 .  
         [0022]    When each control member  100  is in the fully-open position  122 , each respective member projection  119  is positioned against each respective flange stop  66 . Flange  60  has an outer diameter  62  that is larger than an outer diameter  140  of housing upstream end  46 . Moreover, when each control member  100  is in the fully-open position  122 , the curved contour of each respective control member portion  106  facilitates increasing a valve effective area for valve  40  in comparison to valves which include substantially planar valve petals.  
         [0023]    Valve  40  is then coupled within a cooling air supply system  120  to supply cooling air to downstream engine components (not shown). More specifically, in the exemplary embodiment, cooling air supply system  120  includes a supply duct  152  used to route cooling air from a compressor, such as compressor  14  (shown in FIG. 1) downstream to cooling plates (not shown) positioned downstream of a gas turbine engine sump (not shown). Duct  152  has a diameter  154  at an exit end  156  of duct  152  that is slightly smaller than an outer diameter  160  of housing upstream end  46 . Accordingly, when housing upstream end lip  68  is welded to duct end  156 , an orientation of valve  40  is fixed with respect to duct  152 . Moreover, because valve upstream end  46  is only slightly larger than duct diameter  154 , the design of valve  40  is considered compact, and existing engine hardware does not require modification to accommodate an increased diameter  140  of valve  40 .  
         [0024]    During assembly of valve  40 , each hinge pin  92  is inserted through a respective sidewall recess opening  90  and through a respective control member  100 . Hinge pins  92  are then welded to securely couple each control member  100  within valve  40 . In the exemplary embodiment, hinge pins  92  may be removed to facilitate replacing control members  100 . Furthermore, because valve  40  is fixedly coupled to duct  152 , the orientation of valve  40  is maintained, thus facilitating reducing valve petal flutter and failure, and increasing a useful life of valve  40 .  
         [0025]    During operation, as fluid flows downstream through supply duct  152  and into valve  40 , fluid pressure forces control members  100  to rotate from fully-closed position  124  to open position  122 . More specifically, fluid pressure forces each members  100  to rotate until each respective member projection  119  contacts a respective flange stop  66 . Because each member portion  106  is curved, and because each member is coupled to valve  40  within a respective sidewall recess  80 , a valve effective area is facilitated to be increased. Furthermore, the curved contour of each member  100  facilitates reducing fluid blockage through valve  40 . As a result, pressure drops across valve  40  are facilitated to be reduced, and flow loss margins within valve  40  are facilitated to be maintained.  
         [0026]    Furthermore, when fluid flow is reversed through a supply duct  152 , or if a supply duct fails upstream from valve  40 , control members  100  rotate to the fully-closed position  124  and fluid is substantially prevented from flowing upstream through valve  40 , or from valve downstream end  44  to valve upstream end  46 .  
         [0027]    The above-described check valve is cost-effective and highly reliable. The check valve includes a pair of control members that include contoured control members. The contoured control members define a blockage area within the valve that is smaller than that of other known check valves, and as such, facilitate reducing pressure losses of fluids flowing through the valve. Accordingly, the fluid is discharged from the check valve with reduced pressure drops across the valve. Furthermore, the check valve substantially prevents fluid from flowing upstream through the valve. As a result, a reliable and cost-effective check valve is provided.  
         [0028]    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.