The present invention relates to oil and gas well drilling and safety valves used in oil and gas well drilling. More particularly, the present invention relates to an improved kelly valve actuator assembly which allows the kelly valve to be opened or closed when the kelly is spinning or still from a remote location.
In the oil and gas well drilling industry, a powered rotary table rotates a kelly and a kelly bushing to rotate the drill string at the rig floor. There is commonly employed a valve to close the drill string bore at the rig floor. Such valves are commercially available devices. Some models have patented features. For example, a recent patent is U.S. Pat. No. 4,293,163 which shows certain improvements in the valve stem and seals associated with the valve. Kelly valves are usually manually operated. A socket associated with the valve stem is receptive of a wrench or other such torque imparting tool. Oil rig workers simply rotate a wrench to close or open the valve. By controlling the flow of fluid through the drill string, the kelly valve can be used to prevent in-line blowouts. A problem exists in that rig workers cannot always reach the kelly valve. Sometimes the valve is too high above the rig floor to reach. At other times the kelly valve might be disconnected from the drill string such as during a trip where pipe is being removed from the well (for example, to replace the drill bit).
There have been some attempts to automatically open and close the kelly valve from a remote location. One such device can be seen in U.S. Pat. No. 3,887,161. In the U.S. Pat. No. 3,887,161, a plurality of hydraulic cylinders are supported by a plate that attaches to the hydraulic swivel portion of the drilling apparatus. The hydraulic cylinders are all connected to a single annular plate which surrounds the kelly valve. An arc-shaped cam is connected to the valve stem. Expansion and contraction of the hydraulic cylinders cause an annular plate to engage the cam and push on the cam thereby rotating the valve stem to close the valve. The apparatus normally is used when the kelly is not spinning, and in fact is retracted during spinning of the kelly to a withdrawn position.
Another remotely operable kelly valve actuator can be seen in U.S. Pat. No. 3,941,348 issued to Mott entitled "Safety Valve." That device provides a remotely operable safety valve mounted between the swivel and the kelly in drilling operation including a spherically shaped valve element which is mounted in a tubular housing rotatable with a swivel sub, the kelly and the drill string. Hydraulic cylinders move the valve element between open and close positions in order to control flow through the drill string and prevent in-line blowouts. As an additional safety feature, a spring moves the valve element to a closed position in the event of a failure of the hydraulic means. The Mott patent uses an annular channel which is connected to a rack. The rack engages pinion gears which are associated with the valve stem. Hydraulic cylinders use an annular ring which supports a plurality of space roller bearings that engage the channel. When the hydraulic cylinders expand, the bearings connected to the ring which is moved by the cylinders engages the channel which forces the racks to move so that the pinion gears are rotated. The Mott patent uses a complex linkage which is maintenance prone and which relies upon a large sequence of extraneous linkage members to insure proper operation.
A fluid collector ring forms an interface between spinning and non-spinning portions of a housing in U.S. Pat. No. 4,519,576 to Mitchel E. Winegeart (applicant herein), entitled "Oil Well Safety Valve For Use With Drill Pipe." In that patent, a drill string safety valve operator provides a rotatable tubular body having a longitudinal through bore for conveying fluids. A valve member is movably disposed within the body for valving the fluid flow through the bore. A crank arm extends from and is coupled to the valve member at the valve stem for moving the valve member between open flow and closed flow positions responsive to rotation of the crank arm. A bearing is carried at the outboard end of the crank arm for transmitting load to the crank arm. An annular ring is supported about the tubular housing and provides a surface that can engage the bearing. Hydraulic cylinders power the annular ring so that the annular ring engages the bearing. Downward movement of the ring causes a corresponding downward movement of the bearing and a corresponding rotation of the crank arm. The apparatus thus allows quick remote closure of the valve during a blowout condition of the drill pipe bore.