Reliable sealing and renovating installed pipes

摘要

Small i.d. laid pipes are sealed and internally renovated by introducing sealant to close off the leaks and blowing through the abrasive followed by recoating with resin. When one or more leaks have been detected in a pipe it is dried out where necessary using compressed hot air; then either (a) finely powdered dry bentonite, which swells up in water; and/or (b) a sealant contg. dried resin dispersion which swells up with water plus inert additives of (c) a finely divided inert material of Sg1 +/-0.8g/cm3 used by means of water, is blown through; when the pipe has been blown through with sealant and, opt. drained with finely divided abrasive, it is filled with mixed water vapour/air at not less than 2 bars pressure or filled or blown through with water in cases where it is dry sealed. After checking that the pipe is leak-free it is cleaned by continuously blowing through compressed air contg. abrasive particles of hardness greater than 4 Moh and average particle size less than 2mm plus, where necessary, a small amt. of the dry setting material already mentioned. Finally the i.d. of the pipe is coated by blowing through an epoxy resin free from any solvent and filled with 40 + /-10 mm long cellulose fibre sand/or 5 + /-3 mm long glass fibres. Pref. resin dispersions are acrylic esters styrene copolymers or polyvinylacetal copolymers; pref. sealants contain dry light-blown clay or polystyrene foam, cork or kieselguhr as inert additives; the sealant binder can also contain fine Portland cement.