Implementation of a Seafloor Sediment Corer With a Novel Hydrostatic Motor

Abstract

AbstractThis work deals with the design and application of a seafloor sediment corer with a novel hydrostatic motor. The motor uses seawater pressure energy as the power for the penetration by the sediment corer. It is automatically triggered by mechanical linkage when the corer lands on the seafloor, enabling the corer to accomplish an initial gravity penetration before the motor is activated. As a key feature of the motor, a hydraulically actuated valve is employed to control the transfer of ambient high-pressure seawater to a vacant chamber. Driven by the pressure transfer, the corer head continuously repeats movements of lifting and lowering, analogous to a pile driver. Since the motor directly uses the seawater as the energy transmission medium, the corer can be very compact in size. The prototype of the sediment corer with the motor was tested in the East China Sea at a depth of 90 m on September 25, 2011. The results of the experiment show that the corer is able to complete nearly 42 hammering action cycles. This demonstrates the feasibility of the seafloor sediment corer with the hydrostatic motor. By extrapolation, the application of the system to deep sea environs, such as at 1,000 m depths, is shown to be feasible as well.