Valves and valve actuation – Fluid actuated or retarded – With mechanical movement between actuator and valve
Reexamination Certificate
1998-09-18
2001-05-15
Lopez, F. Daniel (Department: 3745)
Valves and valve actuation
Fluid actuated or retarded
With mechanical movement between actuator and valve
C092S136000, C074S057000, C074S089100
Reexamination Certificate
active
06231027
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a rotating actuator for use with valves and chokes that features a driving member with a variable helix angle. This variable helix angle allows the actuator to generate greater torque near the end of its travel when it is needed to close a valve or operate a choke. The high torque rotating actuator lends itself to use with a subsea drilling and production system used in offshore oil and gas wells. This system uses an extension spool between the standard wellhead and production flow package. Flow control valves are positioned in the extension spool. These valves are ball type valves requiring a 90 degree rotation of the valve between the open and closed positions. Since these valves are being used subsea at water depths beyond the access of divers, remote actuation of the valves is required. The high torque rotating actuator of the present invention allows remote operation of the valve and provides additional torque required to operate the valve when it is needed most.
2. Description of the Related Art
U.S. Pat. No. 4,925,154 to G. S. Baker shows a gate valve with a supplemental actuator. The supplemental actuator uses a series of roller cams with the actuator spring to increase the closing force of the actuator during the last portion of its stroke.
A helically shaped cam for operating a gate valve is shown in the brochure entitled “The Cameron ½ 10,000 psi WP Half-Turn Manual Gate Valve”. The assignee of the current invention manufactures and sells this valve.
SUMMARY OF THE INVENTION
This invention relates to a rotating actuator for use with valves and chokes that features a driving member with a variable helix angle. This variable helix angle allows the actuator to generate greater torque near the end of its travel when it is needed to close a valve or operate a choke. The high torque rotating actuator is designed for use with valves and chokes and includes a generally cylindrical housing with a valve actuation stem centrally located within the housing. A cylindrical drive bushing has a plurality of helical grooves formed on its exterior and is internally splined to mate with matching splines on the exterior of the stem. An intermediate head is axially adjacent the drive bushing with a central bore through which the stem extends and includes a plurality of longitudinal grooves on its exterior. An annular piston is between the drive bushing and housing. The annular piston is reciprocable within the housing by hydraulic pressure with a series of belleville springs providing a fail safe close power source. The helical grooves on the exterior of the drive bushing have a variable helix angle to provide a greater torque to the stem at the end of the belleville springs travel. The annular piston has two sets of cam rollers on its interior. One set engages the helical grooves of the drive bushing and the second set engages the longitudinal grooves in the intermediate head. When the annular piston is reciprocated by hydraulic force or spring force, the axial motion of the piston is converted to rotary motion by virtue of the helical grooves in the drive bushing. The stem includes an end configuration to mate with a valve and choke and impart the stems rotary motion to the valve or choke.
In a second embodiment, the high torque rotary actuator is configured with the drive bushing inside the intermediate head to give a shorter overall configuration. As in the preferred embodiment, the high torque rotary actuator includes a generally cylindrical housing with a stem coaxially positioned within the housing. The drive bushing is axially adjacent the stem and includes a bore for receiving the stem. An intermediate head is annularly positioned between the drive bushing and the housing with the intermediate head including a plurality of longitudinal grooves. A pressure responsive piston is formed on the stem with the piston reciprocable within a bore formed in the intermediate housing. The drive bushing includes a plurality of helical grooves with a variable helix angle. The stem has two sets of cam rollers on its end. One set engages the helical grooves of the drive bushing and the second set engages the longitudinal grooves in the intermediate head. When the piston is reciprocated by hydraulic force or spring force, the axial motion of the piston is converted to rotary motion by virtue of the helical grooves in the drive bushing. The stem includes an end configuration to mate with a valve or choke and impart the stems rotary motion to the valve or choke.
A principal object of the present invention is to provide a high torque rotating actuator that can generate a higher output torque nearer the ends of its travel than at the beginning.
Another object of the present invention is to provide a high torque rotating actuator that is compact and can be used on tightly spaced subsea tree valve configurations.
A final object of the present invention is to provide a high torque rotating actuator that can be used with valves or chokes.
These with other objects and advantages of the present invention are pointed out with specificness in the claims annexed hereto and form a part of this disclosure. A full and complete understanding of the invention may be had by reference to the accompanying drawings and description of the preferred embodiments.
REFERENCES:
patent: 2612312 (1952-09-01), Clarke
patent: 3298659 (1967-01-01), Cupedo
patent: 3391722 (1968-07-01), Ligh
patent: 4504038 (1985-03-01), King
patent: 4838102 (1989-06-01), Bode et al.
patent: 4925154 (1990-05-01), Baker
patent: 5134923 (1992-08-01), Wexler
patent: 5447095 (1995-09-01), Weyer
patent: 6032920 (2000-03-01), Takahashi et al.
“The Cameron ½” 10,000 psi WP Half-Turn Manual Gate Valve, Apr. 1988, 2 Pages.
Baker Gerald S.
Garnham David
Hart Brian
Wolff Danny K.
Cooper Cameron Corporation
Duke Jackie Lee
Lopez F. Daniel
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