GB446625A - Process for the manufacture of reinforced concrete pipes and the like hollow bodies - Google Patents

Abstract

446,625. Reinforced-concrete pipes. OVERVAD, M., 9, Hadsherredsvej, Aarhus, Denmark. Oct. 17, 1935, No. 28757. [Class 99 (ii)] [See also Group V] In a process for centrifugally moulding concrete pipes and like hollow bodies having an internal metal pipe reinforcement, an outer layer of concrete is first moulded in a rotating mould, a metal pipe slit longitudinally in one or more places is then applied to the interior, and finally an inner layer of concrete is moulded centrifugally, whereby the concrete, or a sealing cement applied near the slits, passes through the slits during the final moulding operation, so as to ensure the solidity of the outer layer. In the form shown in Fig. 1, the pipe 3 is slit longitudinally in one place, and the edges overlap at 4, 5. In other forms, one or more open slits may be employed. The open slits may be covered by a curved strip fitting against the inner surface of the pipe 3, and secured thereto on one side only of the slit. The metal pipe may be formed of two or more parts overlapping at the edges. The slit metal pipe may be resilient, so that it can be compressed to a smaller diameter to facilitate its insertion into the outer moulded layer. The inner edge 5 of the pipe may be provided with a flange 9, Fig. 6, to form a recess to receive sealing cement 10. In another form, Fig. 7, the edge 5 is bent to provide a hollow rib 11 which is filled with sealing material before the pipe is inserted in the mould, openings 12 being provided to enable concrete to penetrate during the subsequent centrifugal moulding. Alternatively, a rib 13, Fig. 8, may be attached to or formed in the pipe so as to prevent dispersion, during moulding, of the sealing material applied behind the flange 9.