Dynamic valve seal arrangement

Abstract

A valve assembly for a fuel injector that includes a sleeve member having an interior chamber, a piston member supported for movement within the interior chamber of the sleeve member and separating an upstream pressure side of the valve assembly from a downstream pressure side of the valve assembly, and a dynamic sealing device mounted to one of the sleeve member and the piston member for sealingly isolating the upstream pressure side of the valve assembly from the downstream pressure side of the valve assembly. The dynamic sealing assembly includes a PTFE seal member having a generally C-shaped cross-section defining an internal cavity having an opening about the outer periphery thereof the seal member, and a helical spring disposed within the internal cavity of the seal member for providing a constant sealing force to the seal member. The dynamic sealing device is positioned in the valve assembly so that the opening of the internal cavity of the seal member faces away from the upstream pressure side of the valve assembly and towards the downstream pressure side of the valve assembly.

1 . A valve assembly for a fuel injector comprising:
 a) a sleeve member having an interior chamber;   b) a piston member supported for movement within the interior chamber of the sleeve member and delimiting an upstream pressure side of the valve assembly and a downstream pressure side of the valve assembly;   c) a dynamic sealing device mounted to one of the sleeve member and the piston member for sealingly isolating the upstream pressure side of the valve assembly from the downstream pressure side of the valve assembly, the dynamic sealing assembly including:
 i) a seal member having a generally C-shaped cross-section and defining an internal cavity having an opening about the outer periphery of the seal member; and 
 ii) a spring member disposed within the internal cavity of the seal member for providing a constant sealing force to the seal member, wherein the dynamic sealing device is positioned in the valve assembly so that the opening of the internal cavity of the seal member faces towards the downstream pressure side of the valve assembly. 
   
     
     
         2 . A valve assembly as recited in  claim 1 , wherein the sleeve member and piston member are adapted and configured to operate as a check valve. 
     
     
         3 . A valve assembly as recited in  claim 1 , wherein the sleeve member and piston member are adapted and configured to operate as a schedule valve. 
     
     
         4 . A valve assembly as recited in  claim 1 , wherein the sleeve member and piston member are adapted and configured to operate as a combined check valve and schedule valve. 
     
     
         5 . A valve assembly as recited in  claim 2 , wherein an axial collar secures the sealing device in a seat formed in a head portion of the piston member of the check valve. 
     
     
         6 . (canceled) 
     
     
         7 . A valve assembly as recited in  claim 4 , wherein a surrounding retainer ring secures the sealing device in a seat formed in a head portion of the piston member combined check valve and schedule valve. 
     
     
         8 - 12 . (canceled) 
     
     
         13 . A check valve assembly for a fuel injector comprising:
 a) a sleeve member having an interior chamber;   b) a piston member supported for movement within the interior chamber of the sleeve member and separating an upstream pressure side of the check valve assembly from a downstream pressure side of the check valve assembly;   c) a dynamic sealing device secured to the piston member for sealingly isolating the upstream pressure side of the check valve assembly from the downstream pressure side of the check valve assembly, the dynamic sealing assembly including:
 i) a seal having a generally C-shaped cross-section formed from PTFE and defining an internal cavity having an opening about the outer periphery of the seal member; and 
 ii) a metallic helical spring disposed within the internal cavity of the seal member for providing a constant sealing force to the seal member, wherein the dynamic sealing device is positioned in the check valve assembly so that the opening of the internal cavity of the seal member faces away from the upstream pressure side of the check valve assembly. 
   
     
     
         14 . A check valve assembly as recited in  claim 13 , wherein an axial collar secures the sealing device in a seat formed in a head portion of the piston member. 
     
     
         15 . A check valve assembly as recited in  claim 13 , wherein the seal member includes exterior surface features for engaging corresponding surface features on the sleeve member. 
     
     
         16 . A check valve assembly as recited in  claim 13 , wherein the seal member includes exterior surface features for engaging corresponding surface features on the piston member. 
     
     
         17 - 20 . (canceled) 
     
     
         21 . An integral valve assembly of a combined check valve and schedule valve for a fuel injector comprising:
 a) a sleeve member having an interior chamber;   b) a piston member supported for movement within the interior chamber of the sleeve member and separating an upstream pressure side of the integral valve assembly from a downstream pressure side of the integral valve assembly;   c) a dynamic sealing device secured to the piston member for sealingly isolating the upstream pressure side of the integral valve assembly from the downstream pressure side of the integral valve assembly, the dynamic sealing assembly including:
 i) a seal member having a generally C-shaped cross-section formed from PTFE and defining an internal cavity having an opening about the outer periphery of the seal member; and 
 ii) a metallic helical spring disposed within the internal cavity of the seal member for providing a constant sealing force to the seal member, wherein the dynamic sealing device is positioned in the integral valve assembly so that the opening of the internal cavity of the seal member faces away from the upstream pressure side of the integral valve assembly. 
   
     
     
         22 . An integral valve assembly as recited in  claim 21 , wherein a surrounding retainer ring secures the sealing device in a seat formed in a head portion of the piston member of the integral valve. 
     
     
         23 . An integral valve assembly as recited in  claim 21 , wherein the seal member includes exterior surface features for engaging corresponding surface features on the sleeve member. 
     
     
         24 . An integral valve assembly as recited in  claim 21 , wherein the seal member includes exterior surface features for engaging corresponding surface features on the piston member.