Abstract: The screw conveyor 200A includes a first flight 211 and a second flight 212 for transporting cake to cake discharging ports 105 in the small diameter section 103. Each flight 211, 212 has a small clearance portion 211a, 212a defining a small clearance d1 and a large clearance portion 211b, 212b defining a large clearance d2 between the tip of the flight and the inner peripheral surface of the small diameter section 103. The whole region of the large clearance portion 211b, 212b of each flight 211, 212 overlaps with the small clearance portion 212a, 211a of another flight 212, 211 at the same point in the direction of the rotation axis C.

Abstract: This invention provides a cleaning method for removing sediment from the inner wall of the rotary drum of a horizontal drum-type centrifugal separator which comprises charging a plurality of solid cleaning medium pieces such as globules, balls, cubes, rods, springs etc., into the rotary drum, supplying a cleaning liquid to the rotary drum, rotating the drum, and discharging the sediment together with the cleaning liquid. The solid cleaning medium is charged into the rotary drum either before centrifugal separation or at the time of cleaning after centrifugal separation.

Abstract: A surface polishing method comprises allowing a holder to hold a flat sheet-like workpiece, placing a pad tape in a location opposite to the holder, the pad tape consisting of a tape substrate and grains bonded to the substrate surface, supplying free grains between the holder and the pad tape, and rotating the holder and/or a mechanism holding the tape, thereby causing the free grains to polish the workpiece. An apparatus for practicing the method comprises a holder capable of holding a flat sheet-like workpiece, a tape holding mechanism located opposite to the surface of the workpiece and carrying a pad tape which consists of a tape substrate and grains bonded to the substrate, a rotary mechanism for rotating the holder and/or the tape holding mechanism, and an abrasive supplying mechanism for supplying free grains between the surface of the workpiece and the pad tape.

Abstract: A concentration measurement apparatus capable of accurately measuring the concentration of suspended matter in a liquid is provided.A transmitter 1 which transmits sound waves, light waves, or the like, and a receiver 2, which is disposed in opposition to this transmitter 1, are provided, small pipes 3 and 4, which enclose the transmitting surface position of the transmitter and the receiving surface position of the receiver, and which are opened in the direction of transmission and the direction of reception, respectively, are provided, and a mechanism for filling these small pipes with a clean liquid or gas is provided.The transmitting surface of the transmitter and the receiving surface of the receiver are not contaminated by means of the deposition or generation of suspended matter, so that it is possible to conduct the accurate measurement of the concentration in a constant manner.