Telescopic internal expanding type plugging device for submarine pipeline

The invention aims to provide a telescopic internal expanding type plugging device for a submarine pipeline. Radial clamping hydraulic cylinders are installed on a left base and a right base respectively. One end of an axial hydraulic cylinder mechanism is fixed to the inner side of a fixing baffle of the right base, and the other end of the axial hydraulic cylinder mechanism is installed in a connector. The connector penetrates a fixing baffle A to be fixed to a convex block. The convex block is fixed to a fixing baffle C. A wedge block is arranged on the left side of the fixing baffle C. A floating plate is fixed outside the wedge block. A cone structure is arranged inside the wedge block. A hydraulic piston rod is arranged inside the cone structure and connected with a center shaft. The center shaft is provided with a circumferential protruding part. The two ends of the protruding part abut against a fixing baffle B and a pressing plate respectively. The fixing baffle B is adjacent to the floating plate and the cone structure. A trapezoid sealing ring for sealing is arranged between the pressing plate and the base baffle. Pressing blocks firmly clamp the inner wall of the pipeline, so that reliability and stability of primary clamping are guaranteed.