Abstract: A plate-type filter press has sidebars carried on fixed frames, and the filter press plates, the queen end and the king end are all supported on the sidebars by means of pins projecting laterally from the plates and the king and queen ends and resting on the bars. The plates and the queen end are able to slide along the bars on their pins, and even the king end is allowed a limited amount of float between stops on the bars. The press is opened and closed by means of double-acting hydraulic piston-and-cylinder units which are mounted on the king end and are coupled to the queen end by longitudinally extending tie rods so as to close the press by pulling the queen end towards the king end.