| 摘要 |
1468780 Pipe joints FREEMAN CHEMICAL CORP 7 Oct 1975 [21 Oct 1974] 40917/75 Heading F2G [Also in Division C3] A spigot and socket joint between vitrified clay pipes 10A, 10B is formed by a factory applied casting 17A of a foamed unsaturated polyester resin within the bell end 12A of pipe 10A, and an 0-ring 23B held in a groove in a factory applied ring 19 of a urethane elastomer or unsaturated polyester resin at the spigot end 11B of the pipe 10B. The composition of the resin for the casting 17A and its method of formation including the application of a primer to the inside of the bell end 12A are given in the Specification. |
