Draining dredger for totally-closed petrochemical engineering dangerous material pipeline

The invention relates to a draining dredger for a totally-closed petrochemical engineering dangerous material pipeline. The dredger comprises a pipe sleeve, a pipe sleeve upper flange and a pipe sleeve lower flange, wherein a driven worm is arranged in the middle of the pipe sleeve and is provided with a drill of which the top is in a threaded shape; the upper end of the driven worm is connected with an upper bearing inlaid in an upper flange groove; the upper bearing is fixed to the pipe sleeve upper flange by a flange sheet through a bolt; the middle and lower part of the driven worm is connected with a lower bearing which is inlaid in a support sleeve groove; a support sleeve is fixed to a flange and is connected with the pipe sleeve lower flange by the flange through the bolt; a pressure release valve is arranged in the middle of the pipe sleeve; a driving worm wheel chamber which is integrated with the pipe sleeve is formed on the lateral upper part of the pipe sleeve; a driving worm wheel which is match