GB1419392A - Process for producing fleeces or mats from short fibres - Google Patents

Abstract

1419392 Making fibrous webs MESSERSCHMITT-BOLKOW-BLOHM GmbH 29 Nov 1972 [22 Dec 1971] 55188/72 Heading D2A Fleeces having unidirectional short fibres are produced by depositing a liquid suspension of fibres on a carrier provided on a drum, the carrier being subjected to a flow of the suspension initiated by allowing the suspension to flow into a collecting vessel with the carrier on the drum being immersed in the collected suspension and moved continuously therethrough by rotation of the drum, the fibres being deposited on the carrier during repeated rotation of the drum, the carrier and fleece thereon being then removed from the drum. The carrier may be an endless band. As shown in Figure 1, an agitating unit 1 contains suspension 2, e.g. of glycerine and reinforcement fibres. A channel 3 with a valve 4 connects unit 1 with collecting vessel 7 of a drum filter 5 consisting of drum 6 rotatably mounted on vessel 7 and driven by an electric motor in the direction shown by arrow 9. The suspension 2 falls into collecting vessel 7 via channel 3, the base 23 of the vessel being in the form of a trough the base of the trough having a curvature conforming to that of the drum 6. The fibres contained in the suspension in the passage of the drum surface through the bath 10 formed in the channel 7 supplemented by the flow of the suspension 2 deposit themselves on the surface of the drum 6 as an even layer 11 which increases in thickness on each rotation of the drum 6. The adhesion of the fibres to the outer surface of the drum is ensured by a falling pressure gradient of air between the exterior of the drum and the interior. For this purpose the casing of the drum consists of a fine-mesh net structure 12 which before starting up is coated with a permeable filter foil 13 of paper, textile or synthetic plastics acting as the carrier. A pipe is introduced into the interior of the drum through an air-tight mount, the end of the pipe being bent downwards so that through the suction effect liquid in the trough 23 penetrating the outer casing of the drum is sucked off, and a cavity with rarified air is created in the interior of the drum so that the fibres deposited on the casing of the drum adhere firmly thereto. The layer of fibres 11 may be cleansed by spraying a cleansing liquid from spray pipe 21 provided with spray apertures, the valve 4 having been closed. The resulting fleece is detached from drum 6 by cutting in the direction of the axis of the drum and then dried, the foil 13 serving as the carrier. The fibres are then fixed with a suitable solution.