Abstract:
An aircraft check valve assembly where the fluid check valve is indexed in rotational position relative to a first duct flange and to a second opposed duct flange and to a clamping band where the check valve includes an annular check valve flange having at least one index tab extending therefrom. The index tab formed in the check valve annular flange engages a void area formed in an outer annular ridge formed in the first and second duct flanges. A clamping band holds the first duct flange to the check valve flange and to the second duct flange where the clamping band is rotationally indexed to the check valve by index fingers formed on the index tab which and extends to occupy a gap formed in a hinge point of the band clamp. The index finger is oriented relative to the operating direction of the check valve to provide for confirmation of the correct orientation of the check valve for error proofing.

Description:
RELATED CASES 
       [0001]    The present application claims priority of U.S. Provisional Patent Application Ser. No. 61/221,951 filed on Jun. 30, 2009. 
     
    
     TECHNICAL FIELD 
       [0002]    This application relates to aircraft fluid check valves and more specifically to aircraft fluid check valves in an aircraft fluid handing system/that are joined to fluid duct flanges using a clamp band where the fluid duct flanges and/or the clamp band are indexed relative to the fluid check valve. The clamp band is indexed to the check valve using index fingers extending from the check valve. This check valve assembly provides both indexing and error proofing 
       BACKGROUND 
       [0003]    Fluid check valves are known and are commonly used in various types of aircraft fluid control systems such as for the engine bleed air system which supplies pressurized airflow to the cabin and auxiliary systems. The check valves allow the fluid being transported within the piping or ducting system to flow in one direction by opening the check valve. When the fluid starts to reverse flow direction, the check valve closes and thereby prevents the flow from reversing. This feature is especially important in aircraft applications where bleed air from the jet engine compressor is used to supply airflow to the aircraft auxiliary systems should an engine compressor stall occur. Immediately upon the onset of compressor stall, the check valve must close and prevent airflow in an opposite direction from the auxiliary system into the engine compressor. If this does not occur and air is allowed to backflow, re-start of the engine is compromised. 
         [0004]    In certain applications, especially in aircraft applications, it is desirable to rotationally index the various system components such as the fluid ducts leading to and from the check valve. Still in some other applications and installations it is also desirable to index or “clock” the clamping band that is used to hold various parts joined to the check valve such as the fluid duct flanges. In some applications, it would also be desirable to prevent the use of a light duty clamping band when a heavy duty clamping band is required. 
       SUMMARY 
       [0005]    A fluid check valve system which incorporates indexing systems for the duct flanges, the check valve and the band clamp is disclosed. The check valve is designed to include at least one index tab which extends from the outside diameter of an annular flange which is attached and extends from the check valve. This index tab engages a corresponding slot formed in an outer annular ridge in at least one of an inlet duct flange and/or an outlet duct flange. This feature indexes or clocks the duct flanges to the check valve. To index the clamping band, an index finger formed on the end of the index tab, extends and passes at least partially through a gap formed by the retention system on the clamping band. Multiple index tabs and index fingers can be used depending on the number of gaps on the band clamp which can be used to prevent the improper clamp design from being used in a given application. For example, if a light duty clamp has one hinge joint in addition to a fastener section, then it cannot be fitted to a check valve assembly that uses three index tabs and index fingers. That configuration would require the use of a heavy duty band clamp that has two hinge joints in addition to the fastener section. 
         [0006]    The indexing feature of the exemplary check valve assembly is useful as a method of ensuring that the inlet duct, the outlet duct and in some cases the clamping band are all properly aligned one to another to ensure proper assembly and operation. Note that in some applications, it is only necessary to index one of the fluid ducts to the check valve. In addition, using the disclosed check valve assembly, proper assembly can be confirmed by visually inspecting the area of the clamping band and confirming the proper orientation of the index finger relative to the check valve flange and how the clamping band fits onto the check valve assembly. 
         [0007]    The inlet (upstream) flange is shaped differently that the outlet (downstream) flange. This feature prevents the check valve from being inadvertently assembled improperly. An additional novel feature of the disclosed check valve assembly is that if the check valve is installed in a reversed orientation, it will not engage the duct flanges properly and a larger gap will appear between the duct flange and the check valve flange that will alert the technician of improper assembly when he/she tries to fit the band clamp. The increased width of the check valve assembly will prevent the band clamp from fitting properly. Using prior check valve systems, this undesirable result was not ready detectable due to the lack of a method to prevent the check valve from being installed backwards. In that case, the valve would open when the fluid was flowing in a direction opposite to that desired. The check valve would then have to be removed and re-installed in the proper orientation. Note that only one of the duct flanges need to be indexed even though the following detailed description discusses indexing both of the duct flanges. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a sectional perspective view of the exemplary check valve with indexing; 
           [0009]      FIG. 2  is a cross-section view of the exemplary check valve having an indexing tab and an indexing index finger and sections of both the inlet and outlet duct flanges; 
           [0010]      FIG. 3  is a cross-section view of the exemplary check valve and a cross-section of both the inlet and outlet duct flanges; 
           [0011]      FIG. 4  is a cross-section view of the exemplary check valve and a cross-section of the check valve flange with an indexing tab and an indexing index finger; 
           [0012]      FIG. 5  is a cross-section view of the exemplary check valve and a cross-section of the check valve flange without an indexing tab or an indexing index finger; 
           [0013]      FIG. 6  is an end planar view of the check valve flange of the exemplary check valve with indexing; 
           [0014]      FIG. 7  is an end planar view of the check valve flange joined to a duct flange of the exemplary check valve with indexing; 
           [0015]      FIG. 8  is a cross-section view of the exemplary check valve with indexing using a clamping band to hold the assembly together. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    Referring now to the discussion that follows and also to the drawings, illustrative approaches to the disclosed systems and methods are shown in detail. Although the drawings represent some possible approaches, the drawings are not necessarily to scale and certain features may be exaggerated, removed, or partially sectioned to better illustrate and explain the present disclosure. Further, the descriptions set forth herein are not intended to be exhaustive or otherwise limit or restrict the claims to the precise forms and configurations shown in the drawings and disclosed in the following detailed description. 
         [0017]    Moreover, a number of constants may be introduced in the discussion that follows. In some cases illustrative values of the constants are provided. In other cases, no specific values are given. The values of the constants will depend on characteristics of the associated hardware and the interrelationship of such characteristics with one another as well as environmental conditions and the operational conditions associated with the disclosed system. 
         [0018]    Now referring to  FIG. 1  of the drawings, a cross-section perspective view of the exemplary check valve assembly  10  having indexing of the various components including a check valve  15  and a first duct flange  20  and a second duct flange  25  is shown. The check valve assembly  10  has at least one primary index tab  16 A which is used to index or “clock” the check valve  15  to a first duct flange  20  (inlet duct) and to a second duct flange  25  (outlet duct). In this embodiment, two additional index tabs  16 B and  16 C are also used for indexing the check valve  15  to the first and second duct flanges  20 ,  25 . The primary index tab  16 A, in conjunction with the secondary index tabs  16 B and  16 C act to rotationally position the check valve  15  relative to both the first flange  20  and a second duct flange  25 . In this manner, the rotational positioning of the check valve  15  relative to the first flange  20  and the second duct flange  25  is predictable and controllable so as to properly position the check valve assembly  10  and its associated fluid ducting to an aircraft fluid control system. Note that in some systems, it is only necessary to index (clock) only one of the duct flanges  20 ,  25  to the check valve  15  which will change the structure of the duct flanges  20  or  25  to eliminate the outer annular ridge  23  which normally has void areas or slots to only accommodate the index tabs  16 A-C in a specific rotation orientation between the duct flange  20 ,  25  and the check valve flange  13 . 
         [0019]    The check valve  15  has a circumferential flange  13  which includes at least one index tab shown as index tabs  16 A,  16 B and  16 C which are spaced at an angle of 120 degrees but could be spaced in any desired manner. The primary index tab  16 A is wider than the secondary index tabs  16 B and  16 C to index the rotational orientation of the check valve  15  to the first and second duct flanges  20 ,  25 . When the check valve  15  is properly rotationally positioned to the first duct flange  20 , the index tabs  16 A,  16 B and  16 C occupy corresponding void areas  41 A,  41 B and  41 C (see  FIG. 7 ) formed in the first flange  20  which allows the check valve flange  13  to properly seat and fit onto the first flange  20 . Note that the width of void area  41 A is wider than either void area  41 B or void area  41 C to fit only with the index tab  16 A. In a like manner, the check valve flange also seats and fits onto the second duct flange  25  when the index tabs  16 A,  16 B and  16 C occupy similar void areas formed in the second duct flange  25 . 
         [0020]    The primary index tab  16 A and the secondary index tabs  16 B and  16 C function to index the check valve  15  but can also include respective index fingers  17 A,  17 B and  17 C which function to not only rotationally index the band clamp  30  but also prevent the improper band clamp from being used in a given application. At the end of the primary index tab  16 A a primary index finger  17 A extends at a right angle and in a like manner, from the secondary index tabs  16 B and  16 C secondary index fingers  17 B and  17 C extend at a right angle from their respective index tabs  16 B and  16 C. 
         [0021]    The first flange  20  can be joined at one end to an ordinary fluid duct section ( 11 ) where flange  20  and the second duct flange  25  can be what is known in the industry as an S.A.E. AS1895 type flange. In fact, in aircraft applications, it is common to position the check valve ( 15 ) between what is known in the industry as AS1895 flanges. The check valve  15  can be any one of a number of prior art check valve designs or it could be the check valve design disclosed in co-pending International Application Ser. No. PCT/US10/40591 filed Jun. 30, 2010, the contents of which is incorporated herein in its entirety, if installation clearance is an issue. 
         [0022]    Now referring to  FIG. 2  of the drawings, a portion of the check valve assembly  10  as shown in  FIG. 1  is shown more clearly illustrating more clearly the primary index finger  17 A. The check valve  15  includes a check valve flange  13  which, in this case, extends to form the primary index tab  16 A and the primary index finger  17 A. The first flange  20  is connected to the flange portion mounting flange portion  38  which includes apertures  37  for mounting and combine to form the mounting flange assembly mounting flange assembly  35 . Seals  21  and  26  contact the first duct flange  20  and the second duct flange  25 , respectively. On the opposite side of seals  21  and  26  contact is made with either side of the check valve flange  13  thereby providing a fluidic seal between the first flange  20  and the check valve flange  13  and in a like manner between the second duct flange and the check valve flange  13 . 
         [0023]    Holding the first flange  20  and the second duct flange  25  together is the band clamp  30  which can be what is known in the art as a “V-Band” clamp which sandwiches the first flange  20  and the second duct flange  25  together with the seals  21  and  26  and the check valve flange  13  all together when the band clamp  30  is tightened. An inner annular ridge  22  is formed on the first flange  20  and extends to hold the seal  21  in place relative to the first flange  20 . An annular ridge  27  extends from the second duct flange  25  and retains the seal  26  in position on the second duct flange  25 . If both the first and second duct flanges  20 ,  25  need to be indexed to the check valve  15 , then both duct flanges  20 , and  25  need to include void areas  41 A,  41 B,  41 C and  43 A,  43 B,  43 C in both the outer annular ridge  23  and in the annular ridge  27  respectively, to receive the index tab  16 A. Now referring to  FIG. 3  of the drawings a cross section of a portion of the check valve assembly of  FIG. 1  is shown where the check valve is shown in a rotational position such that  FIG. 3  does not show the primary or secondary index tabs  16 A,  16 B,  16 C or primary or secondary index fingers  17 A,  17 B,  17 C. Extending from the first flange  20  is an annular ridge  22  and an outer annular ridge  23  where the inner annular ridge  22  retains the seal  21  in position on the first flange  20 . Because there is not a primary index tab  16 A or secondary index tabs  16 B,  16 C in this particular orientation of the check valve assembly  10 , there is an outer annular edge shown  23  and not one of the void areas  41 A,  41 B,  41 C. In other words, the outer annular ridges  23  and  27  are present except where there are void areas  41 A,  41 B,  41 C in outer annular ridge  23  and void areas  43 A,  43 B,  43 C (not shown) in annular ridge  27  for accommodating the primary or secondary index tabs  16 A,  16 B or  16 C. In this manner, the first flange  20  and second duct flange  25  can be rotationally indexed to the check valve  15  since the primary and secondary index tabs  16 A,  16 B,  16 C must be located within those void areas  41 A,  41 B,  41 C and  43 A,  43 B,  43 C (see  FIG. 7 ) where the outer annular ridges  23  and  27  has been removed on not only the first flange  20 , but in an identical manner on the second duct flange  25 . If either one of the duct flanges  20 ,  25  do not have to be indexed, then the outer annular ridge  23  or the annular ridge  27  can be deleted. 
         [0024]    According to the present check valve assembly  10  with indexing, the first and second duct flanges  20 ,  25  are indexed in rotational position with respect to the check valve  15  through the use of index tabs including at least the primary index tab  16 A and in this case, the secondary index tabs  16 B and  16 C which, when properly positioned, engage void areas created in the  23  formed in the first flange  20  and in the annular ridge  27  formed in the second duct flange  25 . Three index tabs and corresponding void areas are shown in the drawings but other numbers of tabs and tab and matching void area shapes can be used and are contemplated within the scope of this disclosure. 
         [0025]    Now referring to  FIG. 4  of the drawings, a portion of the check valve  15  where the primary index finger  17 A is formed on the primary index tab  16 A to make up that portion of check valve flange  13 . An annular segment cavity  29  is shown as formed in one side of the check valve flange  13  to provide for clearance for the seal  21  and the inner annular flange  22  that are used in conjunction with the first flange  20 . The primary index tab  16 A is shown as part of and extending from the check valve flange  13 . Formed from the primary index tab is the primary index finger  17 A. The primary index finger  17 A is used to position the band clamp  30  on the assembly during assembly where the primary index finger  17 A extends into one of the gaps  55 A,  55 B or  55 C formed by either the hinge joints  50 A or  50 B or by the fastener  49  (see  FIG. 8 ). 
         [0026]    Now referring to  FIG. 5  of the drawings, a cross section of the check valve assembly  10  is shown which more clearly illustrates the section of the check valve flange  13  which is not in the area of any of the index tabs  16 A,  16 B or  16 C.  FIG. 5  shows a section of the check valve  15  and the attached check valve flange  13  that includes the annular segment cavity  29  where the check valve flange  13  includes at its extreme edge an annular flange ridge  18 . Note that the annular segment cavity  29  continues around the surface of the check valve flange  13  and accommodates the seal  21  and the inner annular ridge  22 . Note that in some applications it is only necessary to index (clock) either the first duct flange  20  or the second duct flange  25  to the check valve  15  but not both. 
         [0027]    Now referring to  FIG. 6  of the drawings a planar view of the check valve  15  is shown. Primary index tab  16 A extends outwardly from the check valve flange  13  and is then deformed in an approximate 90 degree angle to form the primary index finger  17 A. The primary index tab  16 A is greater in width than the secondary index tabs  16 B and  16 C and consequently the void area  41 A formed in the outer annular ridge  23  formed in the first flange  20  is wider o accommodate the increased width of the primary index tab  16 A. 
         [0028]    At a position approximately 120 degrees from the primary index tab  16 A is a secondary index tab  16 B which is narrower than the primary index tab  16 A. In a substantially identical manner, the secondary index finger  17 B is formed by bending the secondary index tab  16 B to form a 90 degree angle to the secondary index tab  16 B. At a distance of 120 degrees following the primary index tab  16 A or the secondary index tab  16 B is another secondary index tab  16 C which in a substantially identical fashion to the secondary index finger  17 B the secondary index finger  17 C is formed by bending the secondary index tab  16 C to a 90 degree angle. Alternative methods of forming the primary and secondary index fingers are possible such as by attaching separate pieces of the index fingers to their respective index tabs or by welding additional material to the index tabs to form the index fingers. Many other methods of producing the index tabs and index fingers are possible, as are known in the art. Also, the spacing between the index tabs can be varied from the 120 degrees shown in this disclosure and will still function as contemplated. 
         [0029]    Now referring to  FIG. 7  of the drawings, a planar view of the mounting flange assembly mounting flange assembly  35  including the check valve flange  13  is shown. In this view the void areas  41 A,  41 B,  41 C formed in the outer annular ridge  23  in the first flange  20  are more clearly shown. The inner annular ridge  22  is shown as a continuous ring segment. Note that the width of the void area  41 A is wider to accommodate the increased width of the primary index tab  16 A. These void areas  41 A,  41 B and  41 C provide clearance for the index tabs  16 A,  16 B and  16 C to occupy when the first flange  20  is assembled to the check valve  15 . Segments of the outer annular ridge  23  have been removed to form the void areas  41 A,  41 B,  41 C whereas the inner annular ridge  22  is continuous. If it is desired to also index or clock the second duct flange  25 , then the annular ridge  27  must be used and void areas or slots  41 A,  41 B,  41 C must be formed in the first duct flange  20  and void areas  43 A,  43 B,  43 C (not shown) must be formed in the second duct flange  25  to accommodate the index tabs  16 A,  16 B and  16 C. 
         [0030]    Now referring to  FIG. 8  of the drawings, a planar view of the exemplary check valve assembly  10  is shown. In this view, it is more clearly illustrated how the primary index finger  17 A and the secondary index fingers  17 B and  17 C work together to ensure that the proper model of band clamp  30  is used with the check valve assembly  15  to clamp the first flange  20  to the second duct flange  25 . A light duty band clamp (not shown) only uses one hinge joint and one fastener whereas, the heavy duty band clamp uses one fastener  49  and two hinge joints  50 A,  50 B as is shown in  FIG. 8 . The gaps  55 A  55 B and  55 C formed in the fastener  49  and the hinge joints  50 A,  50 B allow for the index fingers  17 A,  17 B and  17 C to extend into the gaps  55 A,  55 B,  55 C if the proper band clamp  30  is used and is rotationally positioned in the proper orientation to the check valve  15 . Also shown is the annular ridge  27  of the second duct flange  25 . 
         [0031]    In this view it is clearly shown how the primary index finger  17 A extends into a gap  55 B formed in the band clamp  30  although the primary index finger  17 A could occupy any of the gaps  55 A,  55 B,  55 C. In a similar fashion, the secondary index fingers  17 B and  17 C extend into the two other gaps  55 A,  55 C formed by the band clamp  30 . Gaps  55 A,  55 B and  55 C formed in the fastener  49  and the hinge joints  50 A and  50 B allow the primary index finger  17 A and the secondary index fingers  17 B,  17 C to pass into the fastener  49  and the hinge joints  50 A and  50 B equally as well one as the other. Thus, this particular configuration only allows for the use of a band clamp  30  having a fastener  49  and two hinge joints  50 A,  50 B. This prevents the inadvertent use of a different model of band clamp  30  not having three gaps  55 A-C or not orientated with the same spacing. 
         [0032]    The present disclosure has been particularly shown and described with reference to the foregoing illustrations, which are merely illustrative of the best modes for carrying out the disclosure. It should be understood by those skilled in the art that various alternatives to the illustrations of the disclosure described herein may be employed in practicing the disclosure without departing from the spirit and scope of the disclosure as defined in the following claims. It is intended that the following claims define the scope of the disclosure and that the method and apparatus within the scope of these claims and their equivalents be covered thereby. This description of the disclosure should be understood to include all novel and non-obvious combinations of elements described herein, and claims may be presented in this or a later application to any novel and non-obvious combination of these elements. Moreover, the foregoing illustrations are illustrative, and no single feature or element is essential to all possible combinations that may be claimed in this or a later application.