Deep set subsurface safety valve with a micro piston latching mechanism
A subsurface safety valve is operable to close a fluid flow path by virtue of an axially movable flow sleeve. The valve includes a recockable actuator and a latch mechanism so that the valve can be moved to a closed position without overcoming the pressure head and frictional forces currently encountered in conventional safety valves. The latch mechanism includes one or more micro pistons.
1. A safety valve comprising:
a) a body,
b) a flow sleeve positioned within the body and axially movable,
c) a valve element pivotably mounted within the body between an open and closed position,
d) a recockable actuator within the body for moving the flow sleeve in an axial direction, and disengaging from the flow sleeve when the valve is in the open position, the recockable actuator including a piston within a chamber, the piston having a bore extending there though, and,
e) a latching mechanism for locking and unlocking the flow sleeve in a given position.
2. A safety valve according to claim 1 wherein said latching mechanism includes a micro piston.
3. A safety valve according to claim 1 wherein the piston further includes an axially extending notch on an exterior surface thereof.
4. A safety valve according to claim 3 wherein the notch includes a shoulder adapted to engage a flange on the flow sleeve to thereby move the flow sleeve in a downward direction as the piston moves in a downward direction.
5. A safety valve according to claim 4 wherein the length of the notch is greater than that of the flange so that there is lost motion between the flow sleeve and the piston when the piston moves in an upward direction.
6. A safety valve comprising:
a) a body,
b) a flow sleeve positioned within the body and axially movable,
c) a valve element pivotably mounted within the body between an open and closed position,
d) a recockable actuator within the body for moving the flow sleeve in an axial direction, and disengaging from the flow sleeve when the valve is in the open position,
e) a latching mechanism for locking and unlocking the flow sleeve in a given position,
wherein the latching mechanism comprises:
an annular body having an interior chamber,
an annular ring positioned within the chamber, and
an annular collet positioned within the annular body.
7. A safety valve according to claim 6 wherein the annular collet includes a plurality of flexible fingers having an outwardly extending sloping surface that terminates with an edge which is adapted to fit within a groove provided in the annular ring.
8. A safety valve according to claim 7 wherein the fingers also included an inwardly extending tab adapted to be captured by an annular groove provided on an exterior surface of the flow sleeve.
9. A safety valve according to claim 6 wherein the annular ring is axially moveable within the interior chamber, and at least one micro piston located within the interior chamber for moving the ring in an axial direction.
10. A safety valve according to claim 9 further comprising a spring located in the interior chamber between the annular ring and the annular body.