Pressure-balanced pull-type manual actuation mechanism for a valve

Abstract

An example manual actuation mechanism includes (i) a piston having: (a) a first flanged portion with a first annular surface area, (b) a second flanged portion with a second annular surface area, (c) a longitudinal cavity bounded by an interior peripheral surface of the piston, and (d) a shoulder on the interior peripheral surface of the piston; and (ii) a pin disposed in the longitudinal cavity of the piston, where the pin has an area with an enlarged diameter configured to interface with and rest against the shoulder of the piston, such that a force applied on the pin in a given axial direction is transferred to the piston, and where a difference between the second annular surface area of the second flanged portion and the first annular surface of the first flanged portion is substantially equal to a cross-sectional area of the pin.

What is claimed is: 
     
       1. A pull-type manual actuation mechanism for a valve, the pull-type manual actuation mechanism comprising:
 a piston having: (i) a first flanged portion with a first annular surface area, (ii) a second flanged portion with a second annular surface area, wherein the first flanged portion and the second flanged portion project from an exterior peripheral surface of the piston, (iii) a longitudinal cavity bounded by an interior peripheral surface of the piston, and (iv) a shoulder on the interior peripheral surface of the piston; and 
 a pin disposed in the longitudinal cavity of the piston, wherein the pin has an area with an enlarged diameter configured to interface with and rest against the shoulder of the piston, such that a force applied on the pin in a given axial direction is transferred to the piston, and wherein a difference between the second annular surface area of the second flanged portion and the first annular surface of the first flanged portion is substantially equal to a cross-sectional area of the pin. 
 
     
     
       2. The pull-type manual actuation mechanism of  claim 1 , wherein the longitudinal cavity is a first longitudinal cavity, and wherein the pull-type manual actuation mechanism further comprises:
 a knob having a second longitudinal cavity therein, wherein the piston is disposed in the second longitudinal cavity of the knob, and wherein the knob is coupled to the piston such that as the knob is pulled in the given axial direction, the piston moves in the given axial direction along with the knob. 
 
     
     
       3. The pull-type manual actuation mechanism of  claim 2 , wherein the knob defines a groove on an interior peripheral surface of the knob, wherein the piston defines a groove on the exterior peripheral surface of the piston, and wherein the pull-type manual actuation mechanism further comprises:
 a roll pin disposed partially in the groove of the knob and partially in the groove of the piston to couple the piston to the knob. 
 
     
     
       4. The pull-type manual actuation mechanism of  claim 2 , further comprising:
 a sleeve disposed in the second longitudinal cavity coaxial with the knob, wherein the sleeve has a third longitudinal cavity therein, wherein the piston is disposed, and is axially movable, within the third longitudinal cavity of the sleeve. 
 
     
     
       5. The pull-type manual actuation mechanism of  claim 4 , wherein the given axial direction is a first axial direction, and wherein the pull-type manual actuation mechanism further comprises:
 a spring disposed about the exterior peripheral surface of the piston such that the spring applies a spring force on the piston in a second axial direction opposite the first axial direction. 
 
     
     
       6. The pull-type manual actuation mechanism of  claim 5 , wherein the spring is disposed between the first flanged portion and a respective shoulder defined on an interior peripheral surface of the sleeve. 
     
     
       7. The pull-type manual actuation mechanism of  claim 4 , further comprising a detent mechanism, wherein the detent mechanism comprises:
 a plurality of balls disposed in a radial array about the sleeve; 
 a spacer that is ring-shaped and interfacing with the plurality of balls; and 
 a spring disposed about an exterior peripheral surface of the sleeve between: (i) a respective shoulder projecting from the exterior peripheral surface of the sleeve, and (ii) the spacer, wherein the piston includes a groove defined on the exterior peripheral surface of the piston, such that as the piston moves in the given axial direction, the spring pushes the spacer in the given axial direction, and the spacer pushes the plurality of balls causing the plurality of balls to move partially in the groove so as to lock the piston in place relative to the sleeve. 
 
     
     
       8. A pull-type manual actuation mechanism for a valve, the pull-type manual actuation mechanism comprising:
 a knob having a first longitudinal cavity therein; 
 a sleeve disposed in the first longitudinal cavity coaxial with the knob, wherein the sleeve has a second longitudinal cavity therein; 
 a piston disposed in the second longitudinal cavity coaxial with the sleeve, wherein the knob is coupled to the piston such that as the knob is pulled in a given axial direction, the piston moves in the given axial direction along with the knob, wherein the piston has: (i) a first flanged portion having a first annular surface area, (ii) a second flanged portion having a second annular surface area, wherein the first flanged portion and the second flanged portion project from an exterior peripheral surface of the piston, (iii) a third longitudinal cavity bounded by an interior peripheral surface of the piston, and (iv) a shoulder on the interior peripheral surface of the piston; and 
 a pin disposed and axially movable in the third longitudinal cavity of the piston, wherein an end of the pin is configured to be subjected to pressurized fluid from an inlet of the valve, wherein the pin has an area with an enlarged diameter configured to interface with and rest against the shoulder of the piston, such that a force applied on the end of the pin via the pressurized fluid in the given axial direction is transferred to the piston, and wherein a difference between the second annular surface area of the second flanged portion and the first annular surface of the first flanged portion is substantially equal to a cross-sectional area of the pin. 
 
     
     
       9. The pull-type manual actuation mechanism of  claim 8 , wherein the knob defines a groove on an interior peripheral surface of the knob, wherein the piston defines a groove on the exterior peripheral surface of the piston, and wherein the pull-type manual actuation mechanism further comprises:
 a roll pin disposed partially in the groove of the knob and partially in the groove of the piston to couple the piston to the knob. 
 
     
     
       10. The pull-type manual actuation mechanism of  claim 8 , wherein the given axial direction is a first axial direction, and wherein the pull-type manual actuation mechanism further comprises:
 a spring disposed about the exterior peripheral surface of the piston such that the spring applies a spring force on the piston in a second axial direction opposite the first axial direction. 
 
     
     
       11. The pull-type manual actuation mechanism of  claim 10 , wherein the spring is disposed between (i) a third flanged portion projecting from the exterior peripheral surface of the piston, and (ii) an end of the sleeve. 
     
     
       12. The pull-type manual actuation mechanism of  claim 8 , further comprising a detent mechanism, wherein the detent mechanism comprises:
 a plurality of balls disposed in a radial array about the sleeve; 
 a spacer that is ring-shaped and interfacing with the plurality of balls; 
 a spring disposed about an exterior peripheral surface of the sleeve between: (i) a respective shoulder projecting from the exterior peripheral surface of the sleeve, and (ii) the spacer, wherein the piston includes a groove defined on the exterior peripheral surface of the piston, such that as the piston moves in the given axial direction, the spring pushes the spacer in the given axial direction, and the spacer pushes the plurality of balls causing the plurality of balls to move partially in the groove so as to lock the piston in place relative to the sleeve. 
 
     
     
       13. A valve comprising:
 a main valve section comprising: (i) a housing, (ii) a sleeve disposed in the housing, wherein the sleeve defines a first port and a second port, and (iii) a movable element configured to move axially within the sleeve; and 
 a pull-type manual actuation mechanism comprising:
 a knob having a first longitudinal cavity therein; 
 a piston disposed partially within the first longitudinal cavity, wherein the knob is coupled to the piston, wherein the piston has: (i) a first flanged portion having a first annular surface area, (ii) a second flanged portion having a second annular surface area, wherein the first flanged portion and the second flanged portion project from an exterior peripheral surface of the piston, and (iii) a second longitudinal cavity bounded by an interior peripheral surface of the piston, and (iv) a shoulder on the interior peripheral surface of the piston, and 
 a pin disposed in the second longitudinal cavity of the piston, wherein the pin is coupled to the movable element of the main valve section, wherein the pin has an area with an enlarged diameter configured to interface with and rest against the shoulder of the piston, such that a force applied on the pin in a given axial direction via pressurized fluid received at the second port acting on a cross-sectional area of the pin is transferred to the piston, and wherein a difference between the second annular surface area of the second flanged portion and the first annular surface area of the first flanged portion is substantially equal to the cross-sectional area of the pin, such that when pressurized fluid is communicated to the first annular surface area and the second annular surface area, the piston is pressure-balanced, and wherein when the knob is pulled in the given axial direction, the piston moves in the given axial direction along with the knob, allowing the pin and the movable element coupled thereto to move in the given axial direction, thereby allowing fluid to flow from the second port to the first port. 
 
 
     
     
       14. The valve of  claim 13 , further comprising:
 a pull-type solenoid actuator mechanism comprising:
 a solenoid tube disposed partially within the housing of the main valve section; and 
 an armature disposed within the solenoid tube, wherein the armature is coupled to the movable element and the pin, such that axial motion of the pin in the given axial direction causes the armature to move axially along with the pin, thereby causing the movable element to move axially in the given axial direction. 
 
 
     
     
       15. The valve of  claim 14 , further comprising:
 a spacer that is ring-shaped and disposed within the solenoid tube, wherein the piston is disposed partially within and interfaces with the spacer, such that pressurized fluid is allowed to traverse unsealed spaces between the spacer and the solenoid tube and between the piston and the spacer so as to be communicated to the first annular surface area and the second annular surface area. 
 
     
     
       16. The valve of  claim 13 , wherein the sleeve is a first sleeve, wherein the pull-type manual actuation mechanism further comprises:
 a second sleeve disposed in the first longitudinal cavity coaxial with the knob, wherein the second sleeve has a third longitudinal cavity therein, wherein the piston is disposed, and is axially movable, in the third longitudinal cavity of the second sleeve. 
 
     
     
       17. The valve of  claim 16 , wherein the pull-type manual actuation mechanism further comprises a detent mechanism, wherein the detent mechanism comprises:
 a plurality of balls disposed in a radial array about the second sleeve; 
 a spacer that is ring-shaped, slidably disposed about the second sleeve, and interfacing with the plurality of balls; 
 a spring disposed about an exterior peripheral surface of the second sleeve between: (i) a shoulder projecting from the exterior peripheral surface of the second sleeve, and (ii) the spacer, wherein the piston includes a groove defined on the exterior peripheral surface of the piston, such that as the piston moves in the given axial direction, the spring pushes the spacer in the given axial direction, and the spacer pushes the plurality of balls causing the plurality of balls to move partially in the groove so as to lock the piston in place relative to the second sleeve. 
 
     
     
       18. The valve of  claim 16 , wherein the given axial direction is a first axial direction, and wherein the pull-type manual actuation mechanism further comprises:
 a spring disposed about the exterior peripheral surface of the piston such that the spring applies a spring force on the piston in a second axial direction opposite the first axial direction, wherein the spring is disposed between the first flanged portion and a respective shoulder defined on an interior peripheral surface of the second sleeve. 
 
     
     
       19. The valve of  claim 13 , wherein the knob defines a groove on an interior peripheral surface of the knob, wherein the piston defines a groove on the exterior peripheral surface of the piston, and wherein the pull-type manual actuation mechanism further comprises a roll pin disposed partially in the groove of the knob and partially in the groove of the piston to couple the piston to the knob. 
     
     
       20. The valve of  claim 13 , wherein the movable element is a first movable element, wherein the main valve section further comprises:
 a second movable element configured to be seated on a first seat defined on an interior peripheral surface of the sleeve, wherein when the second movable element is seated on the first seat, the second movable element blocks the second port, wherein the first movable element is disposed within the second movable element, wherein the first movable element is configured to be seated on a second seat defined on an interior peripheral surface of the second movable element, and wherein when the first movable element moves axially off the second seat, the second moveable element follows the first movable element and moves off the first seat, thereby allowing fluid to flow from the second port to the first port.