Experimental study of self-locking seal structure based on full ocean depth sediment pressure retaining sampler

Abstract

The full ocean depth environment is characterized by high pressure, low temperature, and high corrosiveness, making it difficult for the current deep-sea sampling equipment to obtain pressure-retaining sediment samples from the seafloor. A new self-locking seal structure is designed with an automatic centering plus floating valve core structure to ensure that the long needle valve core only carries the axial load and autonomously fits the sealing cone of the pressure retaining device. The novel self-locking seal design makes the sampler seal more reliable under high pressure. We conducted a series of experiments to verify the sealing performance of the self-locking seal structure, and the test results show that the self-locking seal structure has better sealing performance when the pressure difference between the inside and outside is larger. This new self-locking seal structure has been used for the full ocean depth sediment sampler during the TS-21 cruise in 2021 and was tested in situ at a depth of 7700 m in the West Philippine Basin, retrieving pressure-retaining sediment samples with 94 % pressure retention.