The invention relates to a
dry ice sublimation hole bottom refrigerating and pressure keeping sampler and a sampling method. The device is mainly composed of a suspension differential action mechanism, a single action mechanism, a control mechanism, a refrigerating mechanism and a pressure keeping mechanism. The method comprises: using
dry ice as
refrigerant,
alcohol as
refrigeration assisting catalyst and secondary
refrigerant, and applying low temperature
alcohol to the hole bottom to refrigerate the
rock core; closing a
ball valve to keep pressure of the
rock sample so as to inhibite the
decomposition of the
hydrate rock core; dismounting a blocking tube and a
drill bit when sampling, dismounting a clamp spring and a clamp spring seat, pulling out a half combining tube and the
rock core from the rock core tube, and using a
liquid nitrogen holdup vessel or a
high pressure container to keep the rock
core sample. When drilling for sampling the rock core, the external tube and the
drill bit gyre, but the internal tube
assembly does not gyre, thus avoiding the damage of
mechanical force to the rock core caused by the gyrus of the drilling tool to a larger degree, improving the rock core sampling rate, integrity and representativeness more effectively, and realizing pure
refrigeration sampling as well as a combination of
refrigeration sampling and rock core pressure keeping; compared with the prior art, the invention has simple process, convenient operation and greatly reduces the cost.