Abstract:
A check valve comprises a valve housing defining a valve opening and a pair of posts arranged on opposed sides of the valve opening. A hinge pin is mounted between the posts. A pair of flapper elements are pivotally mounted to the hinge pin for rotation between a closed position in which they close the valve opening to prevent fluid flow through the opening, and an open position in which they permit fluid flow through the opening. The check valve further comprises a unitary element having at least one washer portion received on the hinge pin and at least one stop portion for forming a stop for engaging the flapper elements in their open position.

Description:
FOREIGN PRIORITY 
     This application claims priority to European Patent Application No. 14461590.3 filed Nov. 20, 2014, the entire contents of which is incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to check valves. 
     BACKGROUND 
     Check valves are valves that allow fluid flow in one direction there through and prevent flow in the opposite direction. They are widely used in a range of applications, for example in air conditioning systems, for example in aircraft air conditioning systems. 
     Check valves commonly include one or more valve elements or flappers located at an opening in a valve housing. The flappers are hingedly supported on a hinge pin mounted to the valve housing for rotation between a closed position in which they lie across and close the opening, preventing fluid flow through the opening in one direction and an open position in which, under the pressure of a fluid (gas or liquid) on one side of the check valve, the flappers rotate from their closed positions so as to allow the fluid to flow through the valve in the opposite direction. Washers are usually provided on the hinge pin in order to assist in locating the flappers on the hinge pin. 
     Typical check valves also often have one or more physical stops, which limit the angle to which the flappers may open. When the flappers move from the closed to the open position, the flappers hit the stop or stops, thereby preventing the flappers from opening further. An example of such a stop is disclosed in U.S. Pat. No. 8,181,669. 
     SUMMARY 
     From one aspect, the present disclosure provides a check valve comprising a valve housing defining a valve opening; a pair of posts arranged on opposed sides of the valve opening; a hinge pin mounted between the posts; a pair of flapper elements pivotally mounted to the hinge pin for rotation between a closed position in which they close the valve opening to prevent fluid flow through the opening, and an open position in which they permit fluid flow through the opening; and at least one unitary element having at least one washer portion received on the hinge pin and at least one stop portion for forming a stop for engaging the flapper elements in their open position. 
     In the disclosed embodiments of this disclosure, therefore, a unitary element performs the function of both a hinge pin washer and flapper element stop. This may prove advantageous in that it may, for example, reduce the number of parts required in the check valve assembly. 
     In embodiments, a washer portion may be arranged between adjacent hinge portions of the flapper elements. In some embodiments, two or more washer portions may be provided between adjacent hinge portions of the flapper elements. In other embodiments, a washer portion may be provided between the hinge portion of a flapper element and an adjacent post, for example between respective ends of the flapper elements and the adjacent posts. In some embodiments, washer portions are provided in both locations. 
     The or each unitary element may have just a single washer portion and a single stop portion. The stop portion may extend away from the washer portion. A plurality of discrete unitary elements may be provided along the hinge pin. 
     The stop portion may take any suitable form. In a simple embodiment, the stop portion may comprise a pair of opposed stop surfaces, one for engaging a respective one of the flapper elements. 
     In order to provide for a relatively large contact area with the flapper elements, in some embodiments the stop surfaces may be formed on elongate arms. Thus in some embodiments, the unitary element may be generally Y-shaped, with the lower limb providing the washer portion and the opposed upper limbs providing the stop portion. 
     In order to locate the unitary element or elements, a locating element, for example a locating pin, may also be mounted between the posts, and the unitary element be provided with a location opening for receiving the locating pin. In embodiments where a plurality of unitary elements is provided, one or more spacer elements may be provided on the locating element between the unitary elements. 
     In other embodiments, a unitary element may comprise more than one washer portion and/or stop portion. For example, the unitary element may comprise multiple washer portions and multiple stop portions. 
     In one embodiment, the unitary element may comprise an elongate medial portion, with one or a plurality of washer portions arranged on one side of the medial portion and one or a plurality of stop portions arranged on the opposite side of the medial portion. 
     The stop portions may be connected by one or more bridging elements, for example joining end portions of the stop elements. In one embodiment, the ends of stop portions are connected by an arcuate bridging element. 
     The end portions of the medial portion may be suitably mounted in the posts. For example, the posts may have upwardly open slots for receiving the end portions of the medial portion. 
     Some embodiments of the disclosure will now be described by way of example only. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  shows a perspective view of a first embodiment of check valve in accordance with this disclosure; 
         FIG. 2  shows a vertical section through the check valve of  FIG. 1 ; 
         FIG. 3  shows a perspective view of a second embodiment of check valve in accordance with this disclosure; 
         FIG. 4  shows a vertical cross-section through the embodiment of  FIG. 3 ; and 
         FIG. 5  shows a perspective view of a third embodiment of check valve in accordance with this disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     With reference firstly to  FIGS. 1 and 2 , a first embodiment of check valve  2  in accordance with this disclosure is illustrated. 
     The check valve  2  comprises a valve housing  4 . The valve housing  4  defines an opening there through in form of two generally D-shaped apertures (not shown) separated by a central web  6  of the housing (see  FIG. 2 ). The opening is closed by a pair of flapper elements  8   a ,  8   b  which are mounted on a hinge pin  10  which is mounted at its ends  12 ,  14  to a pair of posts  16  which extend upwardly from the valve housing  4  on opposed sides of the valve opening. In the illustrated embodiments, the posts  16  are formed integrally with the valve housing  4 , although in other embodiments they may be formed as separate components and suitably attached to the valve housing  4 . 
     As can be seen from  FIG. 2 , the hinge pin  10  is provided with an enlarged head  18  at one end  14 , the enlarged head  18  being received within a bore  20  formed in one of the posts  16 . The other end  12  of the hinge pin  10  is formed with a circumferential groove  22  which receives a circlip  24  which is received in a bore  26  in the other mounting post  16 . The circlip  24  retains the hinge pin  10  to the posts  16 . 
     Each flapper element  8   a ,  8   b  comprises a generally D-shaped planar portion  28   a ,  28   b  which closes the respective valve opening, and a number of mounting lugs  30   a ,  30   b  having bores  31  formed there through to receive the hinge pin  10 . In the illustrated embodiment, each flapper element  8   a ,  8   b  is provided with three mounting lugs  30   a ,  30   b , although any number of mounting lugs  30   a ,  30   b  may be provided on each flapper element  8   a ,  8   b.    
     The check valve  2  further comprises a plurality, in this case four, unitary washer/stop elements  32 ,  34 ,  36 ,  38 . In this case a pair of inner unitary stop/washer elements  34 ,  36  is provided symmetrically between two sets of adjacent lugs  30   a ,  30   b  of respective flapper elements  8   a ,  8   b  on either side of the check valve centerline. A second pair of outer, unitary washer/stop elements  32 ,  38  is provided between the outermost lugs  30   a ,  30   b  of the respective flapper elements  8   a ,  8   b  and the posts  16 . The respective inner unitary elements  34 ,  36  and outer unitary elements  32 ,  38  are mirror images of one another. It will be understood that the terms “inner” and “outer” used in this context refer to the relative positions along the length of the hinge pin  10 , the inner unitary elements  34 ,  36  being nearer the middle of the hinge pin  10  and the outer unitary elements  32 ,  38  being nearer the ends of the hinge pin  10 . The respective unitary elements  32 ,  34 ,  36 ,  38  are arranged parallel to one another. 
     The unitary elements may, for example, be made from a low friction material such as Stellite (which may be useful in high temperature applications) or even aluminum or composite material, for example a fibre or carbon fibre composite material, having a metallic or polymeric matrix (for lower temperature applications). An example composite material would be a carbon filled PEEK (polyether ether ketone). 
     Each of the inner unitary washer/stop elements  34 ,  36  is generally Y-shaped having a lower, washer portion  40  and an upper, stop portion  42 . The washer portion  40  is received between the mounting lugs  30   a ,  30   b  of the flapper elements  8   a ,  8   b  and has a bore  44  which is received over the hinge pin  10 . As can be seen in  FIG. 1 , the washer portion  40  is less wide than the stop forming portion  42 , being provided with relief pockets  46  formed on opposed sides thereof. 
     The upper, stop portion  42  comprises a pair of opposed limbs  48 , each having a stop surface  49 . The limbs  48  are angled such that they will receive the planar portions  28  of the flapper elements  8   a ,  8   b  along the entire length of the stop surface  49  when the flapper elements  8   a ,  8   b  move to the open condition so as to maximize the surface area of contact between the flapper elements  8   a ,  8   b  and the stop portion  42 . The limbs  48  are also sized such as to engage substantially along the entire height of the planar section  28   a ,  28   b  of the flapper elements  8   a ,  8   b . This minimizes the impact loading on the flapper elements  8   a ,  8   b.    
     The inner unitary elements  34 ,  36  also comprise a bore  50  at the lower end of the stop portion  42  which receive a locating pin  52  which is mounted to the posts  16  vertically above the hinge pin  10 . The locating pin  52  has a similar construction to that of the hinge pin  10  having an enlarged head  54  received in a counterbore  56  of one post  16  and a groove  58  receiving a circlip  60  at the other end of the locating pin  52  for retaining the locating pin  52  in the check valve  2 . 
     The outer unitary stop/washer elements  32 ,  38  also comprise a lower, washer portion  40  and an upper, stop portion  42 . The washer portion  40  of the outer unitary elements  32 ,  38  are similar to those of the inner elements  34 ,  36 , having a bore  44  receiving the hinge pin  10 . 
     The stop portion  42  of each of the outer unitary elements  32 ,  38  is, however, shorter than the stop portion  42  of the inner unitary elements  34 ,  36 . Thus, as can be seen for example in  FIG. 1 , the outer unitary elements  32 ,  38  have a truncated stop section  42  compared to the stop section  42  of the inner elements  34 ,  36 . This is because the flapper elements  8   a ,  8   b  are shorter at their ends than at their middle, meaning that there need only be a smaller contact area provided by the stop portion  42 . 
     It will be understood that the stop surfaces  49  of the respective stop portions  42  on the respective unitary elements  32 ,  34 ,  36 ,  38  will be arranged parallel to and coplanar with one another so as to engage the planar portion  28   a ,  28   b  of the respective flapper elements  8   a ,  8   b.    
     The outer unitary elements  32 ,  38  also comprise a bore  50  received on the locating pin  52 , similarly to the inner unitary elements  34 ,  36 . In addition, a plurality of spacing elements  62  are received on the locating pin  52  between adjacent unitary stop/washer elements  32 ,  34 ,  36 ,  38 . Whilst these spacers  62  are not essential, they may assist in locating the unitary stop/washer elements  32 ,  34 ,  36 ,  38 . 
     In the above embodiment, a plurality of discrete, unitary stop/washer elements  32 ,  34 ,  36 ,  38  are used. However, it may be possible to integrate two or more of these elements. The embodiments of  FIGS. 3 to 6  illustrate alternative arrangements in which a single unitary body incorporates multiple washer portions and stop portions. 
     With reference to  FIGS. 3 and 4 , a second embodiment of check valve  102  is illustrated. 
     Similarly to the check valve  2  of the first embodiment, the check valve  102  comprises a valve housing  104 . The valve housing  104  defines an opening there through in form of two generally D-shaped apertures (not shown) separated by a central web  106  of the housing (see  FIG. 4 ). The opening is closed by a pair of flapper elements  108   a ,  108   b  which are mounted on a hinge pin  110  which is mounted at its ends  112 ,  114  to a pair of posts  116  which extend upwardly from the valve housing  104  on opposed sides of the valve opening. In the illustrated embodiments, the posts  116  are formed integrally with the valve housing  4 , although in other embodiments they may be formed as separate components and suitably attached to the valve housing  104 . 
     As can be seen from  FIG. 4 , the hinge pin  110  is provided with an enlarged head  118  at one end  114 , the enlarged head  118  being received within a bore  120  formed in one of the posts  116 . The other end  112  of the hinge pin  110  is formed with a circumferential groove  122  which receives a circlip  124  which is received in a bore  126  in the other mounting post  116 . The circlip  124  retains the hinge pin  110  to the posts  116 . 
     Each flapper element  108   a ,  108   b  comprises a generally D-shaped planar portion  128   a ,  128   b  which closes the respective valve opening, and a number of mounting lugs  130   a ,  130   b  having bores  131  formed there through to receive the hinge pin  110 . In the illustrated embodiment, each flapper element  108   a ,  108   b  is provided with three mounting lugs  130   a ,  130   b , although any number of mounting lugs  130   a ,  130   b  may be provided on each flapper element  108   a ,  108   b.    
     To this extent the check valve  102  of the second embodiment is similar to that of the first embodiment. However, the check valve  102  differs from the check valve  2  in other respects. 
     In particular, instead of having multiple discrete unitary washer/stop elements  32 ,  34 ,  36 ,  38 , the check valve  102  of the second embodiment has a single unitary washer/stop element  132 . 
     The unitary washer/stop element  132  comprises a medial rib  134  having a plurality of washer portions  140  extending downwardly therefrom, and a plurality of stop portions  142  extending upwardly therefrom. In this embodiment, the washer portions  140  are arranged parallel to one another and comprise a pair of outer washer portions  140   a ,  140   d  which are arranged between mounting lugs  130   a ,  130   b  and the adjacent posts  116  and a pair of inner washer portions  140   b ,  140   c  between adjacent mounting lugs  130   a ,  130   b . The shape of each of the washer portions  140  is the same. Each washer portion  140  is formed with a bore  144  for receiving the hinge pin  110 . 
     The upper, stop portions  142  comprise three generally parallel, inner diverging limbs  144  and a pair of outer limbs  146 . More or less inner limbs  144  may be provided in other embodiments, and their lateral positions may be different from those illustrated. 
     The outer ends of the limbs  144 ,  146  are joined by an arcuate bridging element  148 . To reduce weight, apertures  150  are provided in the bridging element  148 . 
     The side surfaces of the inner and outer limbs  144 ,  146 , the bridging element  148 , the medial rib  134  and an upper portion  151  of the washer elements  140   a ,  140   b  together form diverging planar stop surfaces  152  which will receive the planar portions  128   a ,  128   b  of the flapper elements  108   a ,  108   b  when the flapper elements  108   a ,  108   b  are in the open position, thereby providing a very large area of contact between the stop surfaces and the flapper elements  108   a ,  108   b , thereby reducing impact forces on the flapper elements  108   a ,  108   b . The bridging element  148  may have a curvature similar to the outer portion of the flapper elements  108   a ,  108   b , such that it engages around a peripheral portion of the flapper elements  108   a ,  108   b.    
     It will also be seen that the unitary element  132  is provided with a pair of lugs  154  formed generally at the ends of the medial rib  134 . Each lug  154  has a pair of parallel flat surfaces  156  connected by circularly arcuate surfaces  158 . Each lug  154  is received in a keyhole shaped slot  160  in a respective post  116 . 
     The keyhole shaped slot  160  has a straight entrance portion  162  and a circular receiving portion  164 . The unitary element  132  will be mounted by aligning the parallel flat surfaces  156  with the entrance portion  162  of the slots  160 , moving the lugs  154  fully into the slots  160  and rotating the unitary element  132  through 90° to the position shown in  FIG. 3  so as to engage the arcuate surfaces  158  of the lugs with the circular receiving portion  164 . The hinge pin  110  can then be inserted through the posts  116  and mounting lugs  130   a ,  130   b  and secured in position. The interaction between the lugs  154  and the slots  160  will assist in retaining the unitary element  132  in position. 
     The unitary element  132  may be made from any suitable material, for example Nitronic 60®, an austenitic stainless steel having good anti-galling properties. The unitary element may be formed by sintering for example. 
     This embodiment may have the advantage of potentially providing an increased stop surface area compared to the first embodiment. 
     Turning now to  FIG. 5 , a modification of the embodiment of  FIGS. 3 and 4  is illustrated. The only difference between these embodiments is the manner in which the unitary element is mounted. For this reason the detail of the check valve  202  which is common with that of the check valve  102  will not be described, only the differences. 
     In this embodiment, the unitary element  232  of the check valve  202  is also provided with lugs  254  which engage within slots  260  in posts  216 . However, lugs  254  are generally U shaped and received within U-shaped slots  260 . Thus in this embodiment the unitary element  232  is retained solely by the hinge pin  210 , with the lugs  254  simply acting to locate, rather than retain, the unitary element  232 . 
     It will be understood that a potential advantage of the illustrated embodiments is that a unitary element may be used to perform both the function of a washer and a stop element. This may reduce the number of components required in assembly of the check valve. 
     Moreover, the components may be made from any suitable material. For example the unitary elements may be made from a low friction or low-galling material such as Stellite, aluminum, a composite material, for example a fibre or carbon fibre composite material, having a metallic or polymeric matrix, or Nitronic 60®. An example composite material would be a carbon filled PEEK (polyether ether ketone). The material of the unitary element may therefore be optimised for its intended purpose, rather than being determined by another component of the check valve. 
     The above description is of specific embodiments only and it will be appreciated that variations may be made to the embodiments without departing from the broad scope of the disclosure as defined by the following claims.