GB1215977A - Machine for forming powdery or paste-like materials into granules - Google Patents

Abstract

1,215,977. Roller and ring extruder. H. LIST. 23 April, 1968, No. 19190/68. Heading B5A. Apparatus for moulding powdery or pastelike materials into a granulate, comprises a pair of oppositely rotating rollers 41, 42 respectively located within and outside the circumference of a rotating ring member 40 and defining a nip whereat the material is compacted into apertures extending through the ring member 40. In the Fig. 5 embodiment, the material is pressed by a smooth roller 42 into apertures extending through the ring member 40, which a roller 41 contacts only at the edges thereof and is provided therebetween with a circumferentially extending recess whereby the material extrudes as strands 46 on the interior of the ring member 40. At the nip 47 of a further similar roller pair 43, 44 the strands 46 are similarly extruded to the exterior of the ring member 40 from whence they are cut by a knife 48. Further pairs of rollers may be provided. In the Fig. 3 embodiment, not shown, a single similar nip (20, 21) is provided whereby the strands (27) are cut by a knife (28) in the interior of the ring member, and a stationary shoe (30) may be provided in the interior of the ring member (23), at the entrance to the nip, which acts to prevent the premature passage through the cavities of powdery materials and has a trough at the trailing end thereof which collects waste material scraped from the interior of the ring member (4) by the trailing contacting edge of the shoe (30). In the Fig. 1 embodiment (not shown), both nip rollers (1, 2) co-operate to pass material into the ring member apertures (5) from which the granulate may be ejected outwardly by compressed air nozzles (8) located within the ring member (4); alternatively, for larger granulate, mechanical ejection devices may be driven by teeth thereon engaging perforations at the end of the ring member (4) or, with a flexible ring member (4), the ejection may be performed by the deflection thereof by rollers or by a jolting action. The ring member (4) is driven by frictional engagement with the nip rollers or by toothed engagement with the interior nip roller (1). Where it is necessary to maintain the material in a plasticized condition, the nip rollers are heated and the granulate solidified by cooling air or gas blown on to the forming member which may be reheated by hot air or inductive means prior to the roller nip. One roller member may also be rotated at a higher velocity or tangentially or radially oscillated. One of the rollers may also be provided with teeth and the forming member may be provided, either externally or internally, with counter teeth at the base whereof the apertures are located.