Inner aligning device for flat welding flange

The invention relates to an internal aligning device for a flat welding flange. The inner aligning device comprises a central shaft, screwing nuts, a rotating support, jacking blocks, connecting rod assemblies and a supporting ring; the screwing nuts are in threaded connection with the front section of the central shaft, a hole is formed in the middle part of the body of the rotating support, the rotating support is connected with the middle section of the central shaft in a sliding mode through the hole, and the surface of the central shaft on the two sides of the rotating support is provided with a limiting part used for limiting transverse movement of the rotating support; and the two connecting rod assemblies each is connected with one of the jacking blocks, a corresponding screwing nut hinge seat and a rotating support hinge seat. According to the internal aligning device for flat welding flange, when rotating the central shaft, the distance between the screwing nuts and the rotating support is shortened