GB767209A - Improvements in or relating to manufacture of pipes by spinning - Google Patents

Abstract

<PICT:0767209/III/1> <PICT:0767209/III/2> Woven glass fibre cloth 11 is wound on a mandrel comprising a cardboard sleeve 12 on a roller 13, either helically or circumferentially. The fibre-coated sleeve is removed from the roller and inserted into the pipe 14 to be lined or the roller may also be inserted and then removed. Metal rings 15, of suitable dimensions to fit inside the pipe and outside the sleeve, are inserted against the edges of the glass cloth 11. The pipe is mounted on rollers 16 and rotated by a roller 18, driven from a motor 20, at a speed sufficient to cause the cloth 11 to expand off the sleeve 12 and cling to the inside of the pipe. The pipe is then stopped and the cardboard sleeve withdrawn. The pipe is rotated again at the same speed while synthetic resin is poured in through a trough in a manner to distribute it evenly, and rotation is continued until the fibre 11 is thoroughly impregnated with the resin. If the resin is cold-setting polyester resin, which advantageously contains 1 per cent oleic acid, it cures without external heat. If hot-curing polyester resin mixture is used external heating may be supplied by burners, which, unless a flame shield is fitted, should not be lit until the pipe is rotating as the liquid resin is inflammable. The plastic material may be in suspension or emulsion with water or an organic liquid, the suspension liquid being eliminated during the spinning. This method may be used to produce pipe linings which are either solid or porous. Porous linings may also be produced by using a plastic material in the form of a foam with air, carbon dioxide or similar inert gas. The glass fibre reinforcement, instead of being wound on a mandrel, may be previously knitted as a tube. Heating, where required, may be by electricity, steam or hot water.