Abstract: Conventional plant to produce peroxomonosulphuric acid (Caro's acid) is large and emphasises extensive cooling, so that it is awkward to transport, can be cumbersome to install beside existing plant and can suffer from relatively expensive capital and/or running costs.In the present invention, Caro's acid is generated continuously in relatively small plant adiabatically, by introducing concentrated hydrogen peroxide into a stream of concentrated sulphuric acid in a reaction chamber dimensioned so that the throughput is very fast. In particularly suitable embodiments, the reaction chamber is annular at the points of introduction of the reagents, its width being greater in the vicinity of the hydrogen peroxide inlet than in the vicinity of the sulphuric acid inlet. The hydrogen peroxide inlet is preferably angled backwardly so that its encounter angle with the sulphuric acid stream is over 90.degree. to about 165.degree..

Abstract: A method for lining a pipe such as a sewer pipe by applying to the interior of the pipe a layer of a settable composition including a mixture of one or more organic resins with one or more inorganic filling materials, thereafter covering the surface of the said layer with sheet material and thereafter compacting the said layer onto the pipe by exerting pressure thereon through the sheet material, the sheet material being in the form of a tube of polyethylene film or other polymeric film and in that the tube is removed after the pipe lining composition has at least partly set by pulling one end thereof through the interior length of the lined pipe.