Small-caliber pipeline rapid maintenance under-pressure plugging sealing cylinder

An under-pressure plugging sealing cylinder for rapid maintenance of a small-caliber pipeline relates to a pipeline maintenance sealing cylinder, and is characterized in that the outer side of a cylinder body is provided with an expansion tile used for expanding outwards, a positive and negative rotation lead screw connected with tapered iron and provided with a hexagon at the top, and the tapered iron which is in contact with the inclined surface of the expansion tile and slides relatively; the guide rail strip is used for connecting the tapered iron and the expansion tile to ensure that the tapered iron and the expansion tile relatively slide in the same plane, the lead sealing plate is used for being in contact with the section of the pipeline to generate deformation to play a sealing role, and the tile pulling hook is used for limiting the expansion tile to only expand in the horizontal direction; the expansion tiles (1) are symmetrically wrapped on the upper and lower inclined irons (3), an elliptical se