SE301618B - - Google Patents

Abstract

<PICT:1032322/C1/1> A device for opening up the fibres of crude asbestos, separated from the source rock, comprises a cylindrical housing closed, at least at one end, by a cylindrical cover and a closed rotatable drum eccentrically mounted on an axial shaft, within the housing. The rotation of the drum defines an annular passage of varying width. A slurry of fibres and liquid is forced into said passage under controlled hydraulic pressure and the fibres are subjected to bending to and fro in constantly varying directions. A baffle plate is mounted on the hub of the drum so as to be concentric with the housing and integral with the drum and form a discharge gap which is narrow in relation to the eccentric annular passage defined by the drum. The driving shaft of the drum may be arranged to perform short reciprocating strokes. As shown, the fibre/liquid slurry is introduced at 36 and following the arrows is forced into the narrow gap between the housing 1, and the drum 30. The drum may have a resilient lining 33 of rubber or synthetic resin. The width of the annular passage may vary, e.g. between 0.5 and 5 mm. After treatment, the slurry passes through the narrow gaps 35 between the baffle plates 34 and the housing, into the chambers 37 and finally into funnels 39 for discharge or subsequent recycling if dressing is not complete. The optional embodiments comprise the reciprocating mechanism for the shaft and also the trap doors 43 in the cylindrical housing, which may be used when the asbestos fibres to be dressed are not tightly adhered and require shorter and less vigorous treatment. A further optional embodiment is illustrated in Fig. 3 (not shown) in which small circumferential grooves are described both on the housing wall and the resilient lining of the drum; this gives a more vigorous treatment to the fibres.