| 摘要 |
1483675 Supporting prestressing wires for pipes INTERPACE CORP 24 April 1975 [29 April 1974] 17072/75 Heading B5A [Also in Division F2] A prestressed concrete pipe for use for example as a buried water pipe, comprises a moulded concrete pipe core 10 with a spigot having an axially extending surface 19 for engagement of an O-ring, a tensioned wire wrapping 21 having an end anchored in the vicinity of the surface 19, the core 10 containing a plurality of pretensioned wires 11 spaced apart circumferentially around the core 10 and extending longitudinally substantially the length of the core, a prestressed hoop 20 contained in the concrete of, and substantially coaxial with, the core 10 and located axially toward from the end face of the core 10 at its spigot end, said pretensioned wires 11 engaging the inside of the hoop 20 and having portions thereof deflected radially outwardly from their points of engagement with the hoop 20 and to-, wards the end face of the core at the spigot end. In the preferred embodiment the wrapping 21 is provided with a protective coating of mortar, the edge 25 of which, together with an external flange and surface 19 of the core 10, house an 0-ring. The O-ring may alternatively be housed in a recess formed by two external flanges of the core 10 or a recess of the core 10, the protective coating stopping well short of the recess in the latter case. The wires 11 may be provided with anchoring means such as nuts 14 and 15 at spigot and socket ends respectively, the latter socket end being formed by a steel bell ring 16. The "wires" may be replaced by strands of glass. The core 10 is manufactured by moulding in a rotatable cylindrical mould, Fig. 2, comprising a cylindrical shell 27 closed at each end by an end ring as at 26, each prestressing wire 11 being engaged by a detachable gripper having a head 29 bearing on the end ring 26. The hoop 20 is placed in the mould outside the wires 11 prior to gripping and is held in its intended position by tie wires 31, Fig. 3,' The mould may then be incorporated into a roller suspension moulding machine or a centrifugal' moulding machine.
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