GB1399724A - Process and apparatus for the conditioning of particles such as fibres - Google Patents

Abstract

1399724 Preparing pulp NEYRPIC-BMB and RHONE-PROGIL 27 July 1972 [4 Aug 1971] 35212/72 Heading D2A Fibres to be used in the wet manufacture of non-woven webs are prepared by dispersing them in a gas, depositing them from the gas onto a moving formainous support whereby a fibrous mat is formed on the support, and moving the support and the mat through a liquid bath. The fibres are stored in hoppers 2, 3, 4 from which they are fed by metering devices 5, 6, 7 comprising perforated drums rotated by motors 5', 6', 7' speed controlled by regulators 5", 6", 7" under the overall control of a proportioner 21 itself controlled by a photoelectric cell 22 monitoring the flow of material in a conduit 11. The proportioner 21 also controls a supplementary fluid supply valve 23 via a regulator 24. The drums of the metering devices 5, 6, 7 are subject to suction in their upper portions and pressure in their lower portions, produced by a fan 26, and the fibres leaving the drums are deflocculated and dispersed by rotary members 8, 9, 10 before entering the conduit 11 where they are entrained in a stream of air produced by a fan 29. The conduit 11 leads to an endless cloth 35 on which the fibres are deposited and which moves over suction boxes 36, 37 and then round a rotating perforated cylinder 38 disposed in a liquid bath 39, the wet fibres being thereafter stored in a bin 41. The bath is fed with liquid at 43 and an overflow 45 is disposed in the cylinder 38 or vice versa. In a modification, Fig 2 (not shown), a vertically extending chamber is interposed in the conduit 11 to facilitate dispersion and mixing of the fibres and the introduction of additives into the chamber under the control of the proportioner 21. In a second embodiment Fig 4 (not shown), the fibres leaving the conduit 11 are deposited between two moving cloths and travel with the cloths through two liquid baths, the wet fibres being thereafter stored in a tower form the base of which they are pumped to a manufacturing machine, a liquid such as water being added to the tower base and the liquid flow being regulated in dependance upon the concentration of the fibres in the suspension leaving the tower. Other additives are intorduced into the tower base and the suspension is mixed therein by an agitator. In a third embodiment, Fig 5 (not shown), the fibres leaving the conduit 11 are deposited direct onto a rotating perforated cylinder disposed in a liquid bath, the fibres thereafter forming with the liquid a fibrous suspension fed direct to a manufacturing machine. Liquid is sprayed onto the cylinder above the bath, and through sprinklers onto the surface of the fibrous suspension in the bath to ensure good immersion of the fibres. In a fourth embodiment, Fig 6 (not shown), fibres are taken from a hopper by a rotary disperser and are directed by the disperser onto a rotating cylinder in a liquid bath, liquid flowing into the cylinder from one side of the bath and out of the cylinder at the other, the outflowing liquid entraining fibres from the cylinder and the resultant suspension being fed to a manufacturing machine. The liquid fed to the bath may also carry fibres in suspension. In a fifth embodiment, Fig 7 (not shown), fibres from a hopper are mixed and dispersed by rotary members and then deposited on a cloth travelling to a liquid bath. In a sixth embodiment, Fig 8 (not shown), fibres from two hoppers are deposited by respective rotary dispersers in succession onto endless cloth so as to form two layers on the cloth, the layers being thereafter sandwiched between the cloth and a second endless cloth for passage through a liquid bath to subsequent storage.