Patent Publication Number: US-2020278032-A1

Title: Dual Seat Valve

Description:
This application is a continuation of U.S. patent application Ser. No. 16/144,175 filed Sep. 27, 2018 which is a continuation of U.S. patent application Ser. No. 14/993,864 filed Jan. 13, 2016, which are each incorporated by reference herein in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The invention relates to a valve for regulating the flow of fluid. The valve may be used as a dump valve in a high pressure fluid system to relieve pressure when desired. It can also be used in any fluid system to provide an extremely tight seal with virtually no leakage, a condition sometimes referred to as a “bubble tight seal” 
     Background of the Invention 
     A bubble tight seal is very desirable, and in some cases required, for pressure decay testing. Currently available technology utilizes highly polished metal to metal seat assemblies, or grease injectable sealing features. Valves using highly polished seat assemblies, can be made to have very small leaks, but not “bubble tight.” Additionally these valves are very susceptible to damage of their highly polished seat assemblies. Another current technology utilizes precision seat assemblies, not highly polished, and a special grease that seals the imperfections of the precision seat assemblies. These valves work as “bubble tight” but required constant greasing to keep them operating properly. 
     When performing a hydrostatic test it is normally a requirement to have a rupture disc in fluid communication with the high pressure fluid that has a rupture rating of not more than 1.5 time the specified hydrostatic test pressure. This is a difficult requirement for most hydrostatic test system to comply with. To comply you are required to dissemble the rupture disc body, remove the currently installed rupture disc, replace it with the appropriate rupture disc, and then reassemble the rupture disc body. Additionally the old certification tag must be removed from the rupture disc body and the new tag installed. Having the certification tag separately attached, usually by a safety wire, can be problematic. This system can lead to a rupture disc that is not properly identified because it is permanently attached to the rupture disc body. 
     Consequently there is a need for a valve that is not highly susceptible to damage and that does not require constant greasing for proper operation, also there is a need for a simple and less burdensome manner for certifying that a correct burst disc was utilized during the testing process. 
     BRIEF SUMMARY OF SOME OF THE INVENTION 
     These and other needs in the art are addressed in one embodiment by a valve that includes two valve seats. A fluid pressure actuated piston has a first valve surface that cooperates with a first valve seat and carries a plunger that is axially movable within the piston. 
     The plunger has a second valve surface that engages a second seat in the valve body. As the valve is opened, the piston initially separates from the first valve seat while the plunger piston still engages the second valve seat. As the piston is further moved away from the valve seats, the second valve surface disengages from the second valve seat. The first valve seat is an elastomeric ring member. Thus as the valve is opened, the piston disengages from the elastomeric ring before the plunger disengages, thereby providing protection for the elastomer from extrusion and erosion. 
     The invention also includes the provision of a rupture disc carrying unit that can be quickly disconnected from the valve by virtue of a quick disconnect coupling. The unit may include a permanently attached certification tag. The unit also is color coded for easy visual identification of the rupture disc pressure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a detailed description of the preferred embodiments of the invention, reference will now be made to the accompanying drawings in which: 
         FIG. 1  is a perspective view of an embodiment of the invention. 
         FIG. 2  is a cross sectional view of an embodiment of the invention. 
         FIG. 3  is a perspective cross sectional view of the front end of the valve shown in  FIG. 1 . 
         FIG. 4  is a cross sectional view of the front end of the valve shown in  FIG. 1  in the open position 
         FIG. 5  is a cross sectional view of the front end of the valve shown in  FIG. 1  with one of the valve seats in the closed position. 
         FIG. 6  is a cross sectional view of the front end of the valve shown in  FIG. 1  with both valve seats in the closed position. 
         FIG. 7  is a cross sectional view of the quick disconnect mechanism for the rupture disc assembly attached to the valve shown in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As shown in perception in  FIG. 1 , an embodiment of the invention of this application includes front housing members  11 ,  12  a central housing member  13 , and an hydraulic actuating assembly  7  which includes fluid inlets and outlets  16 ,  17  for moving a piston  18  housed within the actuating assembly  7  as shown in  FIG. 2 . 
     A quick disconnect rupture disc assembly  8  is removable attached to the front portion of the valve and will be discussed in greater detail below. 
     Housing portions  11 ,  12 , and  13  are bolted together as shown in  FIG. 4  by a plurality of bolts  40  and  72 . 
     Actuating assembly  7  and a spacer plate  14  are secured to housing  13  via a plurality of bolts  6 . 
     The interior of housing portion  11  is provided with a blind bore  26  which includes a first valve seat  27 . An annular ring member  31  surrounds valve seat  27  and includes a second valve seat  32  as shown in  FIG. 4 . Ring member  31  is secured to housing portion  11  by a retainer ring  33  having a beveled section  72  and a plurality of bolts  35 . Ring member  31  may be formed of an elastomeric material such as polyurethane. 
     A hollow sleeve member  21  having a front surface  70  shown in  FIG. 5  and an aperture  71  in the front surface is threadably attached to piston  18 . 
     Front surface  70  includes a forward facing valve surface  37  which is adapted to engage valve surface  32  of ring member  31  as shown in  FIGS. 5 and 6 . 
     A plunger  24  is movably positioned within a chamber  5  located within sleeve  21  and extends through aperture  71 . A plurality of Bellville springs  22  normally bias flange  25  against the inner forward surface of sleeve portion  70 . 
     Plunger  24  includes a frusto-conical valve surface  28  which is adapted to mate with first valve seat  27 , when the valve is in a closed position. Plunger  24  and valve seat  27  may be made from stainless steel. 
     Second housing portion  12  is positioned between housing portions  11  and  13  and includes an interior chamber  36 . 
     As shown in  FIG. 3 , high pressure fluid enters the valve through an inlet  9  and passageway  5 . In the closed position shown in  FIG. 6 , fluid flow is blocked by the first valve seat and surfaces  27 ,  28  and second valve seat and surfaces  32 ,  37 . 
     When it is desired to open the valve, pressurized fluid is applied through inlet  16  in the actuator assembly  7  which moves piston  18  to the right as shown in  FIG. 5 . Movement of piston  18  separates valve seat  32  and second valve surface  37  as shown in  FIG. 5 . However springs  22  will maintain valve seat  27  and first valve surface  28  in contact with each other. Springs  22  are compressed initially when the valve is moved to the closed position as shown in  FIG. 6 . To close the valve assembly, piston  18  is moved by fluid pressure to first cause valve seat  27  and valve surface  28  to engage. Further movement of the piston  18  to the left as shown in  FIG. 6  will cause plunger  24  to engage surface  27  thereby forcing plunger  24  to compress springs  22 . 
     Thus, as the piston  18  is retracted under fluid pressure, valve seat  32  and valve surface  37  will separate but springs  22  will maintain plunger  24  and valve seat  27  and first valve surface  28  together. As the piston  18  moves further to the right as shown in  FIG. 4 , valve surface  28  will move from valve seat  27  and the valve is in the fully open position. Fluid exits chamber  36  via an outlet passageway  4  in housing portion  12  as shown in  FIG. 3 . When the dump valve is opened surface  37  will disengage first before the plunger  24  thereby protecting the elastomeric valve seat  31  from extrusion and erosion. 
     According to a further aspect of the invention a quick disconnect rupture disc assembly  8  is attached to a top portion of housing portion  12  as shown in  FIG. 7 . The assembly includes a body  54  having a fluid inlet  91  and a fluid outlet  92 . 
     As shown in  FIG. 7 , the top portion of housing  7  includes a first fitting  65  which has an interior passageway  52  which is in fluid communication with inlet port  9 . 
     The top portion of housing  7  includes a second fitting  41  which is in fluid communication with chamber  36  via a passageway  67 . 
     A pair of quick disconnect members  56  are removably connected to fittings  65  and  41 . Each disconnect member includes a sleeve  53  which is axially moveable to disconnect members  56  from fittings  41 ,  65  in a manner known in the art. See for example U.S. patent number  3 / 404 ,  705  the entire contents of which incorporated herein by reference thereto. Any one of the known quick disconnect mechanisms known in the art may be used that include an axially movable outer sleeve. Sleeves  53  are rigidly attached to a handle  64 . 
     The upper portion of quick disconnect members  56  are connected to a rupture disc housing  54  which includes a passageway  55  in fluid communication with passageway  68 . 
     A rupture disc  59  is held in place by a shoulder  57  and plug  73  and is located within passageway  55 . Plug  73  passages  74  and is held in place by a second plug  61 . 
     A plurality of housing  54  with different pressure rated rupture discs may be provided. The rupture disc assembly may be quickly connected to the valve body by grasping handle  64  and moving the cylindrical sleeves  53  in an upward direction. 
     Coupling member  56  may then be placed over fittings  41  and  63  and moved downwardly. Sleeves  53  can them be moved downwardly to connect members  56  to fittings  41  and  65 . 
     To disconnect the quick disconnect assembly from the valve, handle  64  is grasped by the user and sleeves  53  can be moved upwardly to disconnect members  56  from fittings  41  and  65  in a known manner. 
     If pressure in inlet  9  becomes too high, rupture disc  59  will burst and fluid will flow from inlet  9  through passageways  68 ,  55 ,  74 , and  67  into chamber  36 . From chamber  36  fluid will exit through outlet  4 .