GB897222A - Pipe sections made of plastics and a method of making them - Google Patents

Abstract

897,222. Non metallic pipes; pipe joints; junction pieces. FARBWERKE HOECHST A.G. Sept. 3, 1959 [Sept. 3, 1958], No. 30171/59. Classes 99(1) and 99(2). A pipe section, especially for effluent pipes, is built up of a plurality of layers of sintered plastic, the inner and outer surface layers being of different plastics each of which possesses at least one desirable chemical or physical property not possessed or possessed in an inferior degree by the other plastic and the intermediate layer consisting of a mixture of the said plastics that bonds the inner and outer layers together. As shown, a branched pipe section consists of an inner layer 1 of polyethylene, an outer layer 2 of polyvinyl chloride and an intermediate layer 3 of a mixture of these substances. The pipe section is formed with socket portions 5 one of which is provided on its inner surface with a layer 6 of adhesive plastic for joining to another pipe section. The outer layer 2 may consist of an adhesive plastic, the free end 8 of the pipe section being connected to another pipe section by means of a bonding sleeve 7. The separate layers may be formed of a plurality of laminations. The pipe section may be made by sintering powdered plastic on the outer surface of a heated core to form the inner layer or on the inner surface of a heated mould to form the outer surface, further layers being formed in succession on the layer first formed by repeatedly heating the core or mould, applying powdered plastic and sintering.