This filter press cylinder is the core actuator of chamber, plate-and-frame, and membrane filter presses. Mounted at the follower end of the press, it extends or retracts its piston rod to move the pressure plate, firmly clamping the filter plate stack to form a sealed, pressure-tight filtration chamber. During high-pressure slurry feeding, the cylinder maintains constant clamping force to prevent leakage between plates; when discharging, it quickly retracts the plate to release the filter cake. Designed for ultra-high pressure (up to 45 MPa) with a maximum thrust of 11,889 kN, the cylinder integrates multi-stage sealing, a high-capacity guide system, and a specially treated piston rod. It delivers extremely high reliability and zero-leakage performance under sustained holding, frequent cycling, and exposure to corrosive media — a critical guarantee for the stable operation of large automatic filter presses.