| 摘要 |
. A surface safety valve hydraulic actuator of modular construction. The actuator includes separately installable, removable, and interchangeable wirecutting and non-wirecutting spring modules, used with the same hydraulic cylinder and bonnet. The bonnet is attached to the body of the valve. A lower stem extends through a lower seal and into the valve body cavity, and is connected to the gate segments of the valve. A hydraulic cylinder is removably attached to the bonnet. An upper stem with a central bore is disposed in the cylinder chamber and carries a piston thereon, and extends through an upper seal in the top of the hydraulic cylinder. A spring module is removably attached to the hydraulic cylinder, and includes a spring can telescoped over the top of the cylinder. The spring can is rotatably connected to an annular spring retainer, which in turn is mounted on the cylinder. A coupling rod is inserted through the upper stem and screwed into the top of the lower stem. A spring coupler is connected to the upper end of the coupling rod, and bears upon the upper surface of a spring plate. In the non-wirecutting spring module, a single coil spring is disposed in the spring can between the spring plate and the spring retainer. In the wirecutting spring module, dual coil springs are used. |
