GB1321273A - Method and apparatus for forming peripheral grooves in pipes - Google Patents

Abstract

1321273 Grooving thermoplastics pipes CHEMIDUS WAVIN Ltd 29 Dec 1971 [22 Oct 1970] 50188/70 Heading B5A The end of a thermoplastics pipe 9 (Figure 2) is grooved by inserting into the heat-softened pipe end a mandrel 2, annular ring 8 and abutment 6, withdrawing the abutment 6 (Figure 3) from the vicinity of the ring 8, deforming the pipe wall radially inwardly to conform to the shape of the ring 8 and mandrel 2, and removing the mandrel 2 to leave the ring 8 seated in the formed groove (see Fig. 4, not reproduced). The pipe end is thickened initially by a shrunk-on sleeve (9a) (Fig. 1, not reproduced); the mandrel 2 and abutment 6, in the form of an axially sliding sleeve, are moved by hydraulic rams (10), (12) (Fig. 1). Deformation is produced by a split cavity mould 16a (Fig. 3). In alternative embodiments, the abutment comprises (a) members pivoted on and withdrawable into the mandrel 2, (b) an expandable spider housed on the mandrel 2, (c) an expansible elastomeric ring as described in Specifications 1,084,888 and 1,124,930, (d) an element integral with the mandrel 2 and withdrawable from the pipe together with the mandrel, which is long enough to still support the ring 8. The annular ring 8 comprises heat resistant, hard, silicone rubber removable for reuse by flexing, or ceramic, plaster, or plaster of paris that are removable by crushing, breaking or dissolving. The ring may be removed by disdismantling several ring components. Alternatively, the ring remains in the groove as a sealing component. The mandrel, pipe or both are movable.