Fail-safe gate valve
AssigneeVetco Gray Inc.
InventorStephen P. Fenton
Life of this patent
Estimating the term…
Abstract
A gate valve has a body with a gate chamber intersected by a flow passage and a stem chamber extending from the gate chamber. A gate is carried in the gate chamber. A stem, when rotated, causes linear movement of the gate between open and closed positions. A neck on the gate extends into the stem portion of the chamber. The neck has a cylindrical outer diameter, and a seal seals the neck to the stem portion of the chamber. The stem extends into engagement with a cavity in the neck. A ball screw interface is located between the stem and the cavity of the neck.
Claims17
A gate valve, comprising:
- a body having a gate chamber intersected by a flow passage and a stem chamber extending from the gate chamber;
- a gate carried within the gate chamber for movement between a closed position and an open position;
- the gate having a neck having a cylindrical outer diameter and extending into the stem chamber;
- a rotatable member;
- an interface between the rotatable member and the neck of the gate for effecting movement of the gate between the open and closed positions in response to rotation of the rotatable member;
- a seal that seals between the stem chamber and the neck, thereby preventing any fluid in the gate chamber from contacting the interface;
- wherein:
- the neck has a pressure area defined by the seal;
- fluid pressure within the gate chamber when the valve is in one position acts against the pressure area to exert a force on the gate urging the gate to the other position and thereby urging the rotatable member to rotate;
- and the gate valve further comprises:
- a clutch for selectively preventing rotation of the rotatable member.
A gate valve having a body with a gate chamber intersected by a flow passage and a stem chamber extending from the gate chamber, a gate carried within the gate chamber, and a stem for causing linear movement of the gate between open and closed positions in response to rotation of the stem, the improvement comprising:
- a neck on the gate with a cavity therein and a cylindrical outer diameter, the neck extending into the stem chamber, the stem having an inner end extending into the cavity;
- an interface between the stem and the cavity in the neck, the interface having mating helical grooves;
- and
- a seal that seals between the stem chamber and the neck, thereby preventing any fluid in the gate chamber from contacting the interface;
- a clutch that engages the stem to selectively prevent rotation of the stem;
- and
- a controller that maintains the clutch in an engaged position in response to an externally applied signal;
- wherein the neck has a pressure area selected to cause the gate to move to a fail-safe position in response to a selected fluid pressure differential across the seal and in the event the signal ceases.
A gate valve, comprising:
- a body having a gate chamber intersected by a flow passage and a stem chamber extending from the gate chamber;
- a gate carried within the gate chamber, the gate having a neck extending into the stem chamber, the neck having a cavity therein;
- a non-rising stem extending into the stem chamber and having an inner end located within the cavity in the neck, the stem having an outer end exterior of the body for rotating the stem;
- a ball screw interface between the neck and the stem for effecting movement of the gate between open and closed positions in response to rotation of the stem;
- a seal that seals between the stem chamber and the neck, thereby preventing any fluid in the gate chamber from contacting the interface;
- and
- a clutch that selectively prevents the stem from rotating in response to fluid pressure in the gate chamber while the gate is in the a normal operating position;
- wherein the neck has a pressure area selected to cause the gate to move to a fail-safe position in response to a selected fluid pressure differential across the seal and in the event the clutch is not in an engaged position.
Dependencies are inferred from the claim text.