GB510034A - Improvements in and relating to the dewatering of materials, especially cellulose and the like on a rotary sieve cylinder - Google Patents

Abstract

510,034. Filters. STRINDLUND, J. April 25, 1938, No. 12380. [Class 46] A method of removing water from materials, especially cellulose, in which a rotary sieve cylinder having a plurality of cells rotates partially immersed in a pulp mixture, is characterised in that each cell at or adjacent the point where it emerges from the mixture is exposed to an internal pressure, whereby the layer of pulp on the cylinder is removed. In the construction shown in Fig. 1, a cylinder provided with cloth or perforated sheet 1 is divided into cells 5, each communicating with a discharge passage 6. During rotation of the cylinder, each passage 6 is brought into communication with discharge water in the interior of the cylinder, substantially at the same time as the associated cell 5 emerges from the pulp mixture, so that water flows through the passage and clears pulp from the cell. In a, further construction shown in Figs. 3 and 4, each cell 5 communicates with a passage 6 which terminates in the interior of the cylinder. The interior is in communication with a chamber 7 provided with a stationary ring 10, which is formed with an opening 11. As each cell submerges, the air in the associated passage 6 is forced into the interior of the cylinder to create a pressure in the chamber 7 and this pressure is communicated to a cell through the opening 11 to loosen the pulp from the cell. Compressed air may also be supplied to the chamber 7 by means of a fan or other device. The de-watered pulp may be transferred to a discharge chamber by means of an apertured suction roller, or two rollers, one a pressure roller and the other an apertured roller. The latter roller may also be a suction roller.