process for continuous extrusion of a plastic mesh tube with polygonal meshes, and device for implementing this process

摘要

1,231,456. Extruding nets. GENERALE ALIMENTAIRE S.A. 1 Aug., 1968 [3 Aug., 1967], No. 36847/68. Heading B5A. A net-extrusion apparatus comprises die rings 24, 28, Fig. 2, having interfitting teeth 25, 30 respectively, which define a corrugated and continuous extrusion gap 31, this gap being obturated by die members 39, 46 apart from an annular gap defined therebetween, the arrangement being such that plasticized material forced outwardly through gap 31 forms a net, e.g. as shown in Fig. 6 (not reproduced), when members 39, 46 are reciprocated axially relative to ring 24, 28. In the embodiment of Fig. 1 die rings 24, 28 are fixed and members 39, 46 are axially reciprocated by a means of an hydraulically, pneumatically, mechanically or electrically driven rod 38, member 46 being connected thereto via a plate 56 and rod 50. The gaps between the rings and the members are adjustable, the latter by displacement of nut 41 and lock-nut 42. Heaters 3 and 11 are provided. Alternatively die rings 24, 28 may be moved with members 39, 46 kept stationary or both rings and members may be moved. Various designs of extrusion gap are described together with the nets produced thereby, Figs. 7a-10b (not shown).