Jacket needle type convection displacement positive pressure sampling device

According to the jacketed needle type convection replacement positive pressure sampling device provided by the invention, when gas replacement and gas sampling are carried out on the sampling tank, the sampling needle is utilized to extend to the bottom of the sampling tank, convection is ingeniously formed in the sampling tank, so that original gas in the sampling tank is effectively removed through the convection effect from bottom to top in the gas replacement stage, and further, the sampling efficiency is improved. In the gas sampling stage, the sampling needle is used as a flow limiting buffer to ensure that the gas pressure rises orderly and the pressure does not rise instantly, so that the sampling tank is prevented from bearing overlarge pressure in a short time. In addition, the sampling needles also play a series connection function, and through series connection of the sampling needles, two or more sampling tanks are effectively connected in series, so that parallel propulsion and sample backup of