Abstract: In ocean science, while the study of dissolved gases in deep-sea water is something of disciplinary frontier, how to obtain seawater samples that can quickly collect the in-situ information on gas components remains a difficult issue. Furthermore, with the existing seawater samplers, the preservation of dissolved gases is often overlooked. The shortcoming of existing routine seawater samplers motivates the design of a new gas-tight deep-sea water sampling system (GTWS), with which the dissolved gases can be well preserved and gases components’ in-situ intact information obtained. Based on the pressure self-adaptive equilibrium technology and effective and reliable sealing, such a GTWS is developed. The pressure self-adaptive equalizer (PSAE) is described in details. Developed according to hydrodynamics principles, the PSAE’s capacity model illustrates that the PSAE’s capacity is supposed to be bigger than or equal to about 12.24% of the GTWS’s capacity. The PSAE’s capacity is in positive correlation with the surrounding water pressure and diversity of temperature (i.e., the greater the hydrostatic pressure and temperature variation are, the greater the PSAE’s capacity should be.) As a kind of effective and reliable dynamic seal, polytetrafluoroethylene-coated O ring is used to achieve the dynamic seal between PSAE’s piston and cavity. The feasibility of this GTWS’s design is verified by gas tightness tests in laboratory and the first sea trial.

Key words: Deep-sea water sampler, Dynamic seal, Gas tightness, Pressure self-adaptive equilibrium