Central cylinder structure of spiral plate heat exchanger

The utility model discloses a central cylinder structure of a spiral plate heat exchanger. The central cylinder structure comprises a hollow cylindrical body, the side peripheral wall of the cylindrical body is at least composed of two arc-shaped walls which are sequentially connected end to end in the circumferential direction and protrude outwards, every two adjacent arc-shaped walls form a group, namely a first arc-shaped wall and a second arc-shaped wall, and the first arc-shaped wall and the second arc-shaped wall are arranged in the clockwise or anticlockwise first circumferential direction. The wall thickness of the first arc-shaped wall is gradually increased to form a structure with the first end portion being small in wall thickness and the second end portion being large in wall thickness, the wall thickness of the second arc-shaped wall is also gradually increased to form a structure with the first end portion being small in wall thickness and the second end portion being large in wall thickness, a