Patent GB-533943-A (GB)
Title: Improvements relating to the opening and cleansing of asbestos fibrous material
IPC: B07B4/00
Filed: 1939-11-14
Abstract: 533,943. Opening and cleaning asbestos &c. TURNER & NEWALL, Ltd., and ELLISON, W. J. Nov. 14, 1939, No. 30065. [Class 120 (i)] Asbestos fibrous material, which may be mixed with other fibres of animal or vegetable origin, are opened by conveying them in a stream of detached tufts or bunches at high velocity into and through the casing of an opener in which a beater having a large number of separated beating elements rotates at a high speed, the clearance between the beating elements and the casing in the area between the regions of admission and discharge being sufficient to prevent any disintegration of the material by rubbing or tearing action between the elements and the casing ; the material is projected into the casing in a substantially tangential direction against the path of the advancing beating elements so that the material is beaten by the rotating elements while it is freely moving in the air and is discharged at another part of the circumference of the casing in the general direction in which the beating elements are then moving. As shown, the opener comprises a series of interconnected smooth-walled casings 26, each with a rotary beater having arms 27 which have a small clearance at the top of the casing ; the fibrous material is carried into the first casing by the air current and is directed by the inlet passage 28 tangentially into the path of the arms 27 which are moving oppositely to the air current at this point, and which knock the bunches of fibres downwards towards or against the wall of the casing and impel the fibres through the passage 38 into the second casing. From the tangential outlet 29 of the last casing the air borne opened fibres pass through the trunk 32 leading to a centrifugal separator 30 where air and fine dust are discharged through the fan 31 which draws air at high velocity through the inlet passage 28, and a perforated drum 25 onto which the fibrous material to be opened is discharged from a feeding mechanism ; the opened asbestos and any rock particles &c. are delivered from the separator 30 to a rotating screen 34 from which the fibres pass to a receptacle 35 while the rock particles &c. and short fibres pass into a hopper 36 and onto a discharging belt 37. If the rock particles are such that they offer great resistance to reduction in size and are not sufficiently reduced for adequate separation in the screen 34, the fibres &c. from the last casing 26 may be conveyed by the air current to a box having an angularly adjustable baffle against which the fibres &c. impinge before the opened asbestos leaves by an outlet leading to the trunk 32, the rock particles falling to the bottom of the box and being discharged through an airsealed valve. The material is fed into the opener from a hopper 11, a slowly moving apron 12 in the hopper discharging the material intermittently upon an inclined lipped plate 14 ; a paddle wheel 13 regulates the delivery of the apron, and a slowly rotating paddle wheel 16 lifts material from the plate and delivers it to a receptacle 17 below from which it is discharged in a shower by a rotating beater 18 down a tapering shoot 19 to a rapidly rotating beater 20 which distributes the material on to a conveyer 22 by which it is discharged over an inclined plate 24 to the surface of the perforated drum 25. The arms 27 of the beaters are preferably arranged spirally in rows along the axes of the beater with substantial spaces between them so that the air current may pass comparatively freely between the arms which may be straight or not and articulated or flexible. For longer fibres the paddle wheel 16 of the feeding mechanism is formed with blades having pins projecting beyond their edges and rotates at a high speed ; the plate 14 has no lip and the material deposited on the plate falls over the end thereof and down the inclined side of a tapering shoot, a rotating beater having arms revolving close to the side of the shoot and separating the material into small pieces which can pass between the beater and side of the shoot to the beater 20.