Abstract:
A flow splitter for accurately dividing fluid flow into different outlets includes a splitter valve and a calibration member. The calibration member blocks a portion of fluid flow to reduce differences in the divided fluid flows.

Description:
BACKGROUND 
       [0001]    This disclosure generally relates to a fluid flow splitter device that provides fuel to two or more outlet ports. More particularly, this disclosure relates to a fluid flow-splitter that provides a desired accuracy of fluid flow division between two or more ports. 
         [0002]    A fuel system for providing fuel flow to an engine, combustor or other energy conversion device can require essentially identical fuel flows to different locations. Such a requirement is measured and specified as a maximum difference between flow rates at each of the outlet locations. Dividing fuel flows between different outlets is often provided by a flow splitter device that includes an electrically or hydraulically actuated valve. The valves are provided to accommodate the desired split of flows over a range of fuel flow rates. The desired accuracy requirements are becoming more stringent and therefore it is desirable to design and develop devices and methods that improve the accuracy in dividing fluid flows among several outlets. 
       SUMMARY 
       [0003]    A fuel delivery system is disclosed and includes a flow splitter that divides fuel flow into two substantially equal flows. The flow splitter includes a splitter valve that divides fuel flow from an inlet into two separate flows that exit through a first outlet and a second outlet. A calibration member is disposed in the first outlet and provides adjustment of fuel flow such that the difference between fuel flows can be reduced and/or eliminated. 
         [0004]    These and other features disclosed herein can be best understood from the following specification and drawings, the following of which is a brief description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]      FIG. 1  is a schematic representation of an example fuel system for a gas turbine engine. 
           [0006]      FIG. 2  is a cross-sectional view of an example flow splitter. 
           [0007]      FIG. 3A  is a cross-section of the example calibration member in a retracted position. 
           [0008]      FIG. 3B  is a cross-section of the example calibration member in an extended position. 
           [0009]      FIG. 4  is a cross-section of the example calibration member mounted within an outlet. 
           [0010]      FIG. 5  is a cross-section of a fixed length calibration plug. 
           [0011]      FIG. 6  is a schematic view of a plurality of fixed calibration plugs. 
           [0012]      FIG. 7  is a cross-section of an example flow splitter including the fixed length calibration plug. 
           [0013]      FIG. 8  is an enlarged cross-section of the example fixed length calibration plug within the flow splitter. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    Referring to  FIG. 1 , a fuel delivery system  10  is schematically shown and includes a fuel controller  14  that receives fuel from a fuel tank  12  and expels a fuel flow to a flow splitter  16 . The flow splitter  16  divides fuel flow F into two substantially equal fuels flows F 1  and F 2 . The flow splitter  16  includes a splitter valve  30  that divides fuel flow from an inlet  24  into two separate flows that exit through a first outlet  26  and a second outlet  28 . A valve member  34  is disposed within a cavity  36  of the splitter valve  30  to provide the desired divided flow. An orifice  40  is disposed within a supply line that provides flow to a portion of the chamber  36 . The orifice  40  controls a relative pressure within the cavity  36  to provide the desired control of the fuel flows F 1  and F 2 . Although an example splitter valve  30  is disclosed, other configurations of valves could be utilized with this disclosure. 
         [0015]    A calibration member  42  is disposed in the first outlet  26  and provides adjustment of fuel flow F 1  such that the difference between fuel flows F 1  and F 2  can be reduced and/or eliminated. Fuel from the first outlet  26  is directed to a first manifold  18 . Fuel flow from the second outlet  28  is directed to a second manifold  20 . The first and second manifolds  18 ,  20  in turn direct fuel to an energy conversion device  22 , such as a combustor for a gas turbine engine or other combustion engine. 
         [0016]    Referring to  FIG. 2 , the example flow splitter  16  comprises a housing  15  within which are formed the inlet  24 , the outlets  26 ,  28  and a cavity  36  for the splitter valve  30 . The features of the housing  15  can be formed by casting, machining, and/or any other fabrication process capable of providing for multiple interconnected passages. 
         [0017]    The example outlets  26 ,  28  are formed as a first portion  44  that is in communication with the cavity  36  for the splitter valve  30 . The first portion  44  includes an open end  45  within which the calibration member  42  is installed. The first portion  44  of the first outlet  26  intersects a second portion  46  that communicates fuel flow out of the housing  15  and to the first manifold  18 . 
         [0018]    The calibration member  42  includes a fixed portion  48  that is threaded into the opening  45  and supports a movable adjusting member  50 . The adjusting member  50  extends into first portion  44  at the intersection with the second portion  46  to block a portion of fluid flow F. The end of the adjusting member  50  includes a restriction  52  that extends a distance  54  into the first outlet  26 . The distance  54  is variable by rotating the adjusting member  50 . The shape of the restriction  52  provides for blocking a sufficient amount of fuel flow to match flows between the outlets  26  and  28 . Substantially equal fuel flows are desired to the first and second manifolds  18 ,  20  to provide the desired proper operation of the energy conversion device  22 . 
         [0019]    Referring to  FIG. 3A , the example calibration member  42  is shown in a retracted position with the restriction end  52  disposed within the fixed portion  48 . The fixed portion includes external threads  58  that provides for mounting into the open end  45  of the housing  15 . The adjusting member  50  includes threads  60  that engage corresponding internal threads of the fixed portion  48 . A seal  56  is provided between the adjusting portion  50  and internal surface of the fixed portion for preventing leakage through the calibration member  42 . 
         [0020]    The adjusting member  50  includes a groove  64  that provides an indication of the length  54  in which the restriction end  52  has been retracted. The groove  64  also provides a visual indication of the narrowed threaded portion relative to the seal  56  within the fixed portion  48 . The visual indication alerts that the narrowed portion of the adjusting member  50  is approaching the seal  56  to prevent errant dislodgement. A head portion  62  of the adjusting member  50  includes a shape that corresponds with a tool for rotating the adjusting member  50  from the retracted position shown in  FIG. 3A . 
         [0021]    Referring to  FIG. 3B , the adjusting member  50  is shown in an extended position where the threaded portion  60  is extended a length  54  from the fixed member  48 . The head portion  62  includes a flange that limits extension of the adjusting member  50  from the fixed portion  48 . 
         [0022]    Referring to  FIG. 4 , in operation, the calibration member  42  is installed with the opening  45  such that the restriction end  52  is disposed within the first portion  44  of the first outlet  26 . The restriction end  52  extends the length  54  into the flow stream F to block a portion of the fluid flow. The fluid flow F 1  is measured and compared to fluid flow F 2  from the second outlet  28 . In the disclosed example, it is desired to match the flows F 1  and F 2  for differing flow rates. The splitter valve  30  divides the incoming fluid flow F into the two flows F 1  and F 2 . However, the splitter valve  30  does not provide the desired accuracy in flow rates. Therefore, the calibration member  42  is provided in the first outlet  26  to provide a fine final adjustment that provides for matched fluid flows F 1  and F 2 . 
         [0023]    The flow matching process begins with the initial installation of the calibration member  42  into the opening  45 . Fluid flow is driven through the flow splitter  16  and the outgoing flows F 1  and F 2  are measured relative to each other. The adjusting member  50  is then extended into the first outlet  26  to block a portion of the fluid flow until the flows F 1  and F 2  are substantially the same, within an acceptable tolerance range. In the illustrated example, the restriction  52  is disposed at the intersection of the first portion  44  with the second portion  46 . However, the calibration member  42 , and thereby the restriction  52  could be placed at other locations with the first outlet  26  as would be consistent with matching flows from the outlets  26  and  28 . 
         [0024]    Referring to  FIG. 5 , once the flows F 1  and F 2  are satisfactorily matched, a fixed plug  66  is installed in place of the calibration member  42 . As appreciated, the calibration member  42  could remain in place and remains a permanent part of the flow splitter  16 . Replacement of the adjustable calibration member  42  with the fixed plug  66  prevents tampering. The example fixed plug  66  includes a restriction of the fixed length  54  that is matched to the length  54  determined to provide the desired flow matching between the outgoing flows F 1  and F 2 . That is, once the proper length  54  is determined that provides for the desired flow matching of the flows F 1  and F 2 , a fixed plug  66  including the same length  54  is installed and the desired flow rates verified. The fixed plug  66  provides the desired flow matching between outgoing flows F 1  and F 2 . 
         [0025]    Referring to  FIG. 6  with continued reference to  FIG. 5 , a plurality of plugs  66 A,  66 B,  66 C are provided and selected based on the length  54  determined through calibration with the calibration member  42 . Each of the plugs  66 A,  66 B, and  66 C include different lengths  54 . Once the length is determined that provides matching flows F 1  and F 2 , one of the plurality of fixed plugs  66 A,  66 B, and  66 C that corresponds to that length is selected and installed within the opening  45  to block a portion of the fluid flow F. 
         [0026]    Referring to  FIGS. 7 and 8 , a calibrated flow splitter  16  is shown and includes the fixed plug  66  of a length  54  within the opening  45 . The second outlet  28  includes a plug  72  that does not block or otherwise restrict flow. The example plug  72  is provided to plug the opening in the outlet  28  that is created during the machining process and formation of the various passages and cavities of the flow splitter  16 . 
         [0027]    The calibrated flow splitter  16  receives flow F from the flow controller  14 . Flow F is divided by the splitter valve  30  into passages comprising the first and second outlets  26 ,  28 . The fixed plug  66  extends into the first outlet  26  a length that blocks a portion of the fluid flow such that the outgoing flows F 1  and F 2  are within a desired range. In the example, the flows F 1  and F 2  are matched; however other relationships and ratios between flows are within the contemplation of this invention. 
         [0028]    Accordingly, the example flow splitter  16  is calibrated to provide a fine adjustment in matching fluid flows beyond the capability of the splitter valve  30 . Moreover, the example flow splitter  16  provides such matched flows without the need for identically machining each of the outlets  26  and  28 . 
         [0029]    Although a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.