Patent ID: 8671987
Filing Date: 2014-03-18
Classification: F16K,H01L,Y10T

Abstract:
1. Two-stage valve apparatus, comprising: a valve body and a valve bonnet enclosing a valve chamber between a first port and a second port; a major valve seat around the second port; a major valve closure assembly positioned in the valve chamber between the first port and the second port including a major valve closure member positioned in axial alignment with the major valve seat and being movable between a closed mode, in which the major valve closure member is seated on the major valve seat to prevent fluid flow between the first port and the second port, and an opened mode, in which the major valve closure member is moved away from the major valve seat to allow fluid flow between the first port and the second port, wherein the major valve closure assembly has an alternate flow channel extending through the major valve closure member between a first location on the major valve closure member that is in fluid-flow communication with the first port when the major valve closure member is seated on the major valve seat and a second location on the major valve closure member that is in fluid-flow communication with the second port when the major valve closure member is seated on the major valve seat; a major piston in a major piston chamber over the valve bonnet and a major piston rod extending from the major piston to the major valve closure member for moving the major valve closure member between the closed mode and the open mode; and minor valve closure apparatus positioned in the alternate flow channel in the major valve closure member between the first location and the second location, said minor valve closure apparatus including a minor valve seat around one opening of the alternate flow channel and a minor valve closure member positioned in axial alignment with the minor valve seat and being movable between a closed mode, in which the minor valve closure member is seated on the minor valve seat to prevent fluid flow between the first location and the second location, and an opened mode, in which the minor valve closure member is moved away from the minor valve seat to allow fluid flow between the first location and the second location, wherein the minor valve closure apparatus includes: (i) a minor piston positioned in a minor piston chamber in the major valve closure member, an upper end of the minor piston chamber over the minor piston being in fluid flow communication with a minor valve actuation fluid duct that extends longitudinally through the major piston rod from above the major piston to the minor piston chamber; (ii) a minor spring retainer plate positioned a distance below the minor valve seat such that there is a space between the minor valve seat and the minor spring retainer plate; (iii) a minor valve closure member connected to the minor piston and positioned in the space between the minor valve seat and the minor spring retainer plate in a manner that accommodates upward movement of the minor valve closure member between the minor valve seat and the minor spring retainer plate to the closed mode and downward movement of the minor valve closure member between the minor valve seat and the minor spring retainer plate to the opened mode; and (iv) a minor valve spring positioned between the minor spring retainer plate and the minor valve closure member for applying a closure force on the minor valve closure member.