| 摘要 |
An accelerator having a tubular housing and a tubular mandrel substantially coaxial arranged for telescoping longitudinal movement within the tubular housing, the accelerator also including: a first piston positioned radially between the tubular housing and mandrel, the first piston being adapted for movement with the mandrel in response to movement of the mandrel in a first longitudinal direction relative to the housing and adapted to resist longitudinal movement in response to movement of the mandrel in a second longitudinal direction relative to the housing; and a second piston positioned radially between the tubular housing and mandrel, the first and second pistons forming a substantially sealed gas chamber therebetween, the second piston being adapted for movement with the mandrel in the second longitudinal direction relative to the housing and adapted to resist longitudinal movement in response to movement of the mandrel in the first longitudinal direction relative to the housing, and whereby the chamber has an increase in pressure in response to movement of the mandrel in both the first and second longitudinal directions relative to the housing until released by a jar mechanism, said accelerator also having fluid reservoirs formed between said tubular housing and mandrel and adapted for receiving an operating fluid therein, said reservoirs adapted for providing said operating fluid adjacent to said first and second pistons opposite said gas chamber, said first and second pistons having at least one seal to separate said gas chamber from said reservoirs. |
