| 摘要 |
A hydraulic, especially a hydrostatic impact device, for example for marine sampling or pile driving, comprises a low pressure reservoir (33) which is completely or partially filled with air or other gas under, for example, atmospheric pressure, and a piston cylinder (34, 35, 49), where the space (35) in the piston cylinder below the piston (10) is openly connected with the low pressure reservoir (33). The impact device's lifting stroke is activated by the opening of a filling valve (6, 71) to the top (34) of the piston from a fluid reservoir (32) at higher pressure than the low pressure reservoir, and the drop stroke is activated by the opening of a drain valve (52a-b) and the draining of fluid from the top of the piston to the low pressure reservoir while at the same time the filling valve closes and vice versa. Between the piston cylinder and, for example, a sampler tube (64, 65) there is provided a so-called jump slide valve (39, 40) which can convert the drop hammer's kinetic energy into potential energy for the entire impact device. The impact device can thereby continue the drop hammer's upwardly directed movement after the completion of the cylinder's lifting stroke. |
