tube made of plastic; see wall transverse and enacting terms for the manufacture of tubes made of plastic are interim wall transverse

摘要

1395962 Extruding partitioned plastics tubes W HEGLER 5 July 1972 [31 July 1971] 31517/72 Heading B5A [Also in Divisions F2 and C1] A plastics tube is extruded having an integral partitioning wall means which extends across the tube interior between the tube wall and follows a helical path axially of the tube, to divide all of the bore of the tube into separate helical passages. The tube wall may be helically corrugated, and the partitioning wall means may be of the hand 24 shown in Fig. 3, dividing the tube diametrically, may be of the opposite hand (25), Fig. 4 (not shown), dividing the tube into three equal segments, or may be of alternating hand 26 and divide the tube into four segments as shown in Fig. 5, The tubes may be coiled around a cylinder which is rotated to scoop air and effluent or sewage through the tube whilst agitated for biological treatment in contact with a biological "lawn" which develops inside the tube, and which treatment is enhanced by additional agitation provided by the tube corrugations. Alternatively, the effluent may be passed through bundles of uncoiled tubes by gravity, or pressure. The tubes may alternatively be used for the conveyance of solid suspensions without settlement of the solids. The tube is extruded from an orifice, Fig. 1 defined between a stationary external die 1, and a mandrel 2 which rotates to define the helical path of a partition wall 16 which is formed by slots 13 extending radially inwardly of the mandrel 2 and to which plastics material is delivered by upstream mandrel grooves 14. The extruding tube is engaged between moving opposed chains of co-operating mould halves 17 which form corrugations, upon application of vacuum via mould passages 21 communicating with stationary vacuum sources 23, the formation of the corrugations being facilitated by communication of the tube interior with atmosphere, by passages 18 through the mandrel 1. The mandrel 1 is mounted for rotation within stationary spider 10 to which it is sealed by a flexibly deformable sleeve 12, urged against the mandrel by the pressure of the plastics 8 within the die head. The 1 is rotated by external sprockets 6 the drive of which is transmitted, by chains passing through the spider arms, to mandrel sprockets 4 housed within a spider cavity containing lubricant and in which a bearing 3 for the mandrel 4 is housed. The mandrel air passages 18 communicate with atmosphere through the spider arms, via an outlet 19 from the mandrel which is located above the level of lubricant 11 in the cavity and to which the ingress of lubricant is prevented by a surrounding drip shield.