Abstract: A vertical pump (1) having a single or plurality of helical blades (10, 11, 12) mounted on a forward end of a rotary drive shaft (2) of the pump. The pump is of nonblocked type in which the helical blade or blades (10, 11, 12) are disposed with superior balance with respect to the rotary drive shaft (2), and is wide in flow passage between blade portions of the helical blades. The pump is particularly suitable for sewage treatment or the like.

Abstract: A screw press for dehydrating slurry and comprising an outer screen casing, a screw shaft, a slurry supplying portion, and a driving unit which rotates the outer screen casing and the screw shaft. The driving unit rotates the screw shaft in one rotational direction and the outer screen casing in the opposite rotational direction. The driving unit comprises a transmission for changing the rotational frequency of at least one of the outer screen casings or the screw shaft. It is possible to have a high dehydrating effect by rotating the outer screen casing in the opposite rotational direction of the screw shaft at a predetermined rotational frequency.

Abstract: A filter press is provided with filter plates supported vertically in a horizontal row in a frame structure and with filter cloth disposed between the filter plates for treating slurries introduced between the filter plates. The filter press includes bars supported at a height above the filter plates to support the filter cloth, shafts disposed orthogonally under the bars, cylinders to move the shafts toward and away from the bars, and vibrators mounted on the shafts to vibrate the shafts. The shafts are moved to come into contact with the bars, and the vibrators are actuated to make the bars vibrate to drop cake remaining on the filter cloth when the filter plates are opened. The filter press further includes photoemissive and photoreceptive devices for detecting deflection and sinking of the bars due to weight of the cake on the filter cloth, and wash pipes for washing down the filter plates and filter cloth.