| 摘要 |
The present invention relates to an apparatus and method for providing hydraulic load compensated time delay in downhole well operations. The apparatus includes a piston stem enclosed by a piston housing. An axial force, acting either in the direction of stretch or in the direction of compression, causes a pressure buildup in one of two hydraulic chambers which are each filled with an incompressible liquid and which are mutually connected through one or more throttle orifices. A sideways floating, supported piston sleeve is arranged between the piston stem and the piston housing. The piston sleeve is adapted to control the differential pressure across the throttle orifice(s) in such a manner that an increasing axial force will, in a predetermined manner, increase the differential pressure across the throttle orifice(s) and hence delay the flow-through of the incompressible liquid from one of the hydraulic chambers to the other chamber, which also causes a predetermined delay of the relative movement between the piston stem and the piston housing. |
