GB1258846A - - Google Patents

Abstract

1,258,846. Screening apparatus. H. H. BURKHARDT, H. M. KURTZ and M. KURTZ [trading as HERMANN FINCKH METALLTUCH - UND MASCHINENFABRIK], 14 Aug., 1970 [17 Sept., 1969], No. 39352/70. Headings BID and B2H. An apparatus for classifying fibrous material in suspension in a liquid or gaseous stream comprises a housing 13, a fixed sieve 18 attached to the housing, a rotatable sieve 19 concentric with and closely adjacent the sieve 18 with an upper portion projecting above the sieve 18 into an upper zone 14 of the housing, an inlet 15 for the stream of fibrous material communicating with the zone 14, a channel 24 in the housing located outwardly of the sieves 18, 19 and below the upper projecting portion of the sieve 19, and an outlet 26 from the channel for discharging coarse fibrous particles, the apertures in the upper portion of the sieve 19 being larger than those in the lower portion which are in turn larger than those in the fixed sieve. An annular shield 28 is disposed between the inlet 15 and the upper portion of the screen 19. The sieve 19 is secured to a plate 21 mounted on a shaft 20 extending through an inner support 22 of the housing and driven by a belt pulley 42. Clearing blades 23 are rigidly mounted on the support 22 and extend close to the inside face of the rotating sieve 19. Below the sieves 18, 19 and extending around the support 22 is a channel 25 which communicates with an outlet 27 for the discharge of medium size fibrous particles. A conical chamber 16 surrounds the fixed sieve 18 and has an outlet 17 for fine fibrous particles. In operation, the stream of fibrous material is fed under pressure tangentially through the inlet 15. The heavier constituents pass along the cylindrical part of the shield 28 in the direction of the arrows 31 and fall into the channel 24. The remaining fibres are forced upwardly (arrows 32) over the conical part of the shield 28 and pass through the gap (arrows 33) between the housing cover 12 and the upper edge of the shield 28. Coarser constituents of the fibrous material on approaching the upper portion of the screen 19 are forced under the action of centrifugal force towards the inside of the shield 28 (arrows 34) and pass under gravity into the channel 24 to be discharged with the heavy constituents through the outlet 26. The medium and fine fibrous particles flow into the interior of the rotating sieve 19 (arrows 41). The fine particles then flow through the lower apertures of the sieve 19 and through the sieve 18 (arrows 35) into the chamber 16 to be discharged through the outlet 17. The medium sized particles retained by the lower part of the sieve 19 and the sieve 18 flow down (arrows 36, 43) into the channel 25 and are ejected through the outlet 2.