Plastic blow molding automatic screen replacing device

The invention discloses a plastic blow molding automatic screen replacing device. The plastic blow molding automatic screen replacing device is arranged between a screw cylinder and a handpiece of a blow molding machine and comprises a main body (1), a middle gate plate (2) and an executing part (3) used for converting pressure of fluid to mechanical energy; the main body (1) is connected with thescrew cylinder and the handpiece separately; the middle gate plate (2) penetrates through the main body (1) and is provided with multiple holes (4), and filter screens (5) are installed at the holes(4); and a sealing ring (6) is arranged in the main body (1) and used for ensuring the sealing property of the front and back contact faces of the middle gate plate (2) and the main body (1), and a spring (7) is arranged in the sealing ring (6). The executing part (3) pushes the middle gate plate (2) to move to enable a used filter screen to be pushed out of the main body (1), then the filter screen located at another hole