Improvements in manufacture of pipe

摘要

709,251. Pipes of fibrous material. GANAHL, C. DE. June 18, 1952 [July 7, 1951], No. 15401/52. Class 99 (2). In a pipe consisting essentially of fibrous rovings, e.g. glass fibres, bonded together by and substantially embedded in a substantially impervious body of plastic material, the rovings are in part disposed in at least two helically wound layers 5, 6, the pitches of the helices being equal in magnitude but opposite in direction, and in part disposed in a layer 7 in which the rovings extend parallel to the axis of the pipe and may be widely spaced. There may be two outer helically wound layers 8, 9 of rovings. The helically disposed rovings may be arranged at an angle of 35 degrees to a plane normal to the axis of the pipe, or at an angle a such that 3 sin2a+2/m sina=1 where m is the ratio of the total cross-sectional area of all the helically disposed rovings to the total crosssectional area of all the rovings extending parallel to the axis of the pipe. The plastic material may be thermosetting or thermoplastic in character, and comprise a composition of styrene and an alkyd resin or vinyl halide resins and copolymers with vinyl esters, nylon, methacrylate resins, polyethylene, phenol-, urea-, and melamine-formaldehyde condensation polymers, cellulose esters and various blends, of these materials, or a natural wax, resin or gum may be employed. The pipe may be made on a machine such as that described in Specification 687,552 wherein packages of glass fibre rovings are carried on a number of horizontal tables revolving about upwardly advancing mandrels onto which the plastic-coated fibres are wound, the machine being modified by the addition of one or more non-rotative tables for the longitudinally applied fibres. In a modification, the pipe has a single outer layer of helically disposed fibres overlying closely-spaced longitudinal fibres.