In Situ Suction Filtration Sampler With Hundreds of Membranes for Deep-Sea Suspensions

Deep-sea microorganisms are highly abundant and diverse and have potential for engineering applications, medicinal uses, and explaining the origin of life. To obtain many long-term time series samples, an in situ suction filtration sampler was proposed, which can wind more than 360 filter membranes with an effective diameter of 60 mm through rollers. A multilayer filter membrane structure was proposed to avoid interactions between filter membranes and seawater. Based on various test results, multilayer filter membrane structures of PET (polyethylene glycol terephthalate, thickness of 0.2 mm)-PES (polyethersulfone, pore size of 0.45 and 1 μm) and PET (thickness of 0.2 mm)-PTFE (polytetrafluoroethylene, pore size of 0.22 μm) were finally selected. These combinations can ensure not only better water-permeability performance but also better strength. Furthermore, based on the data from the water-permeability test of the filtration membranes, the finite element software ANSYS Fluent was used to study the movement and aggregation laws of suspensions in the filtration chamber. The peak concentration in the suspension increases with increasing particle size and decreasing filter membrane pore size. Finally, the device was successfully operated in a 45 MPa high-pressure chamber. Additionally, in sea trials, the sampler successfully obtained an in situ suspension in a methane leakage area.