Abstract: A deep sea microbial sampler with concentrated and isobaric function is designed to get sample with original characters. When large quantity of sea water which driven by deep-sea pump passing through filter membrane, microbial will be captured. Pressure-retaining sample is realized with precharged accumulator. Key techniques of on-line concentrated sampling are analyzed and relations of accumulator precharge pressure and pressure-retaining results are studied. Practical experiments shows that with overflowing technique concentrated sampling can be realized, when sampling depth is 6 km and accumulator precharge pressure is great than 25 Mpa, pres and accumulator precharge pressure is great than 25 Mpa, pressure decrease of sample in 6 h is less than 2% compared with original pressure. Deep sea trial with depth of 1 900 m shows that using accumulator can realize isobaric sampling reliably.

Key words: Sampling technique, Deep sea, Isobaric, Microbial Concentration