Cork-bitumen coatings for embedding underground pipes - used for remote heating applications

摘要

Process for mfg. a corrosion-protective, thermally-insulating, bedding-in matl., by mixing hot molten bitumen and cork-flour, the matl. being used for the underground laying of pipes carrying a heating medium, e.g. steam, hot water thermal oil etc., esp. pipes for remote- or long distance-heating. The novelty is that heated bitumen is 180-220 degrees C. is stirred intensively while max. 20 pts. wt., esp. 8-15 pts. wt. of a cork-flour mixt. is added, the cork-flour consisting of different types of cork of various density, including natural cork. The cork-flour may include a small amt. of perlite and is pref. stirred continuously into the bitumen using stirrer-blades rotating at 175-200 r.p.m. The pref. mixing plant is included in the claims. In addn. to providing good corrosion protection, this mixt. increases the thermal insulation, thereby reducing heat losses.