Rotational shear valve

A method for sealing a passage, the method comprising:

• providing a valve body having a flow passage therethrough;
• providing a gate, the gate comprising a cylinder rotated about a gate axis, the gate being located within the valve body and moveable in a longitudinal direction along the gate axis from an open position to a closed position, the gate permitting flow through the flow passage in the open position and a solid portion of the outer diameter of the gate obstructing the flow passage in the closed position, wherein the valve body is shaped to engage the gate as it moves in the longitudinal direction along the gate axis and initiate rotation of the gate about the gate axis between the open and closed positions when a shear surface of the gate is a predetermined axial distance from the closed position;
• exerting force on the gate in the direction of the gate axis to cause the gate to move in the direction of the gate axis from the open to the closed position, the gate rotating about the gate axis as it moves from the open position to the closed position;
• and
• shearing a cable located in the flow passage with axial and rotational shear forces from the gate as the gate moves from the open position to the closed position, wherein the shear surface of the gate is operable to exert simultaneous axial and rotational shear forces against the cable disposed in the flow passage while moving between the open position and the closed position, such that a fully severed section of the cable is swept into an orifice of the gate, thereby reducing damage to the shear surface of the gate by preventing severed material of the severed section from being caught between the shear surface of the gate and the valve body.

A valve assembly comprising:

• a valve body having an axial flow passage therethrough;
• and
• a gate, the gate comprising a cylinder rotated about a gate axis and an orifice perpendicular to the gate axis, the gate being located within the valve body and moveable in a longitudinal direction along the gate axis from an open position to a closed position, the orifice registering with the axial flow passage in the open position and the gate rotating about the gate axis while moving axially from the open position to the closed position, wherein the valve body is shaped to engage the gate as it moves in the longitudinal direction along the gate axis and initiate rotation of the gate about the gate axis between the open and closed positions when a shear surface of the gate is a predetermined axial distance from the closed position;
• at least one seat located in the valve body, the at least one seat forming a seal against an outer diameter of the gate;
• and
• a shear surface at an end of the orifice, the shear surface being the last portion of the orifice to register with the axial flow passage as the gate moves from the open position to the closed position, wherein the shear surface is operable to exert simultaneous axial and rotational shear forces against a conduit disposed in the axial flow passage while moving between the open position and the closed position, such that a fully severed section of the conduit is swept into the orifice of the gate, thereby reducing damage to the shear surface of the gate by preventing severed material of the severed section from being caught between the shear surface of the gate and the seat.

A valve assembly comprising:

• a valve body having an axial flow passage therethrough and a lateral bore transverse to the axial flow passage;
• and
• a gate, the gate comprising a cylinder rotated about a gate axis, the gate being located within the lateral bore and moveable in a longitudinal direction along the gate axis from an open position to a closed position, the gate permitting flow through the axial flow passage in the open position and a solid portion of the outer diameter of the gate obstructing the axial flow passage in the closed position, the gate comprises a slot on the outer diameter of the gate, the gate comprises an orifice, and the gate rotating about the gate axis while moving axially from the open position to the closed position,
• the slot having a helical portion extending around the outer diameter as it extends in the direction of the gate axis, and wherein the valve body comprises a key, at least a portion of the key being located in the slot, so that when the gate moves along the gate axis, the key causes the gate to rotate about the gate axis,
• the slot further comprises a straight portion that extends along the gate axis and does not rotate in helical fashion about the outer diameter and the key is located in the straight portion of the slot when the valve is in the open position so that when the gate moves from the open position to the closed position, the gate initially moves along the gate axis without rotating and then begins rotating when the key reaches the helical portion,
• the orifice being perpendicular to the gate axis and having opposite ends at the outer diameter of the gate, the orifice registering with the axial flow passage in the open position and having a shear surface, the shear surface being the last portion of the orifice to register with the axial flow passage as the gate moves from the open position to the closed position, and wherein the transition from the straight portion of the slot to the curved portion of the slot is a predetermined axial distance from the shear surface of the orifice so that the gate begins to rotate when the shear surface is the predetermined axial distance crossing a circumference of the axial flow passage, wherein the shear surface of the gate is operable to exert simultaneous axial and rotational shear forces against a conduit disposed in the axial flow passage while moving between the open position and the closed position, such that a fully severed section of the conduit is swept into the orifice of the gate, thereby reducing damage to the shear surface of the gate by preventing severed material of the severed section from being caught between the shear surface of the gate and the valve body.