Method comprises placing a pipe inside a prefabricated sheath of similar length and slightly larger diameter and made of a relatively corrosion-resistant heat shrinkable plastic material, and heat shrinking the sheath to a tight fit onto the pipe. Pref. the sheath is pressurised with hot air during insertion of the pipe to sustain the shape of the sheath, and may be suspended vertically over a mandrel which can also accept the pipe and emit hot air. Pref. the supporting base can spin to ensure uniform heating. The sheath is esp. of polyethylene, pref. an irradiated grade, e.g. by the 'Raychem' (RTM) process. Esp. suitable for corrosion protection of steel pipes for conveying hydrocarbons or similar fluids. Can be used to apply sheaths =0.5 mm. thick, but more usually =1 mm. Prefabricated sheating is more free of pores or thickness variation than cladding applied as coatings from fluidised bed or flame spray techniques.
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