Disengageable valve backseat system and method
A valve assembly includes a valve body, a bonnet coupled to the valve body, a stem within the stem bore, a bonnet cap axially aligned with the bonnet along a stem bore axis, and a valve drive train coupled to the stem. The valve assembly also includes a first eutectic ring, positioned between a bonnet cap interior surface and an upper shelf of the valve drive train, the first eutectic ring blocking axially upward movement of the valve drive train when in a solid state, and a second eutectic ring, positioned between a lower bonnet cap interior surface and a lower shelf of the valve drive train to fill a gap, wherein the bonnet cap is configured to move in an axially downward direction after the first and second eutectic ring transition to a flowable state.
1 . A valve assembly, comprising:
a valve body having a stem bore extending along a stem bore axis and a flow bore extending along a valve body axis;
a bonnet coupled to the valve body;
a stem extending along the stem bore axis and within the stem bore;
a bonnet cap axially aligned with the bonnet along the stem bore axis;
a first eutectic ring;
a second eutectic ring; and
wherein the bonnet cap is configured to move in a direction after the first eutectic ring transitions to a flowable state from a solid state and after the second eutectic ring transitions to the flowable state from the solid state.
2 . The valve assembly of claim 1 , further comprising:
first drain holes adjacent to the first eutectic ring, wherein the first eutectic ring flows through the first drain holes in the flowable state; and
second drain holes adjacent to the second eutectic ring, wherein the second eutectic ring flows through the second drain holes in the flowable state.
3 . The valve assembly of claim 1 , wherein the first eutectic ring has a first melting point substantially similar to a second melting point of the second eutectic ring.
4 . The valve assembly of claim 1 , wherein the first eutectic ring has a first melting point substantially different from a second melting point of the second eutectic ring.
5 . The valve assembly of claim 1 , further comprising:
an actuator coupled to the stem.
6 . The valve assembly of claim 1 , wherein a space is created between a backseat profile of the bonnet and the stem when the bonnet cap is moved in the direction.
7 . The valve assembly of claim 1 , wherein a gap is closed when the bonnet cap is moved in the direction.
8 . The valve assembly of claim 1 , wherein a first inner diameter of the first eutectic ring is smaller than a second inner diameter of the second eutectic ring.
9 . The valve assembly of claim 1 , wherein a first axial thickness of the first eutectic ring is greater than a second axial thickness of the second eutectic ring.
10 . The valve assembly of claim 1 , wherein the bonnet cap is configured to move in the direction by using a tool to grip flats on an outer surface of the bonnet cap.
11 . A valve assembly, comprising:
a valve drive train;
a valve stem;
a bonnet cap;
a first eutectic ring, wherein the first eutectic ring, when in a first state, blocks movement of the valve drive train, and wherein the first eutectic ring, when in a second state, enables the valve drive train to move; and
a second eutectic ring, wherein the second eutectic ring, when in a third state, blocks movement of the bonnet cap, the valve drive train, or the valve stem, and wherein the second eutectic ring, when in a fourth state, enables the bonnet cap, the valve drive train, or the valve stem to move.
12 . The valve assembly of claim 11 , further comprising:
first drain holes.
13 . The valve assembly of claim 11 , further comprising:
second drain holes.
14 . The valve assembly of claim 12 , wherein the first eutectic ring, when in the second state, flows out of the valve assembly via the first drain holes.
15 . The valve assembly of claim 13 , wherein the second eutectic ring, when in the fourth state, flows out of the valve assembly via the second drain holes.
16 . A method for disengaging a valve stem from a backseat profile of a bonnet of a valve assembly, comprising:
providing a valve assembly, the valve assembly including a first eutectic ring at a first position and a second eutectic ring at a second position;
melting the first eutectic ring and the second eutectic ring to a flowable state; and
causing a bonnet cap to be driven in a direction after the first eutectic ring and the second eutectic ring flow, at least partially, out of the bonnet cap when in the flowable state.
17 . The method of claim 16 , wherein providing the valve assembly is for a testing and verification procedure.
18 . The method of claim 16 , wherein causing the bonnet cap to be driven in the direction also causes a valve drive train to be driven in the direction.
19 . The method of claim 16 , wherein the melting creates a gap between a lower bonnet cap interior surface of the bonnet cap and a lower shelf.
20 . The method of claim 16 , wherein the first position of the first eutectic ring is axially above the second position of the second eutectic ring along a stem bore axis.