| 摘要 |
1,231,660. Spirally-wound plastics pipes. DYNAMIT NOBEL A.G. 1 Oct., 1968 [2 Oct., 1967], No. 46630/68. Heading F2P. In a method of making a rigid pipe from at least one, spirally wound, continuous profiled band 4 of thermoplastic material having at least one longitudinally extending-channel and at least one longitudinally extending tongue 5 the band 4 is spirally wound, in a heated thermoplastic state, around a mandrel 1 so that the tongue engages in the channel, the channel being temporarily widened, or the tongue temporarily compressed, before being so engaged and finally cooled. As shown, the band 4 is fed between a plurality of pressure rollers 2, 2 and the co-operating rotatable mandrel 1, the band being guided by an element 9 on a wedging tool 8 which spreads apart the channel 6 before the rollers 2, 2 press it over the tongue 5. Cooling air is supplied between the rollers 2 through a pipe 3 the tool 8 being provided with passages which can supply solvents, hot air, &c., to the joint or, direct an additional soft band between the tongue 5 and the channel 6 before being bonded together. Instead of spreading the channel 6 the tongue 5 may be compressed, Fig. 4, not shown. Pipes having several overlapping band layers may be formed of bands having a plurality of tongues and channels, Figs. 8-10, not shown. The mandrel 1 is conically tapered at its take-off end, the angle of the rollers 2, 2 being adjustable with respect to the longitudinal axis of the pipe. |
