GB770888A - Improvements in and relating to structural materials - Google Patents

Abstract

Cork granules having a flexible moisture proofing coating are made by treating the granules with a moisture-proofing liquid and drying them, the liquid penetrating a short way into the surface of the <PICT:0770888/III/1> granules during drying. The granules may be baked or carbonized before treatment, and the liquid may be emulsified bitumen As shown, the cork granules 10 are first carbonized by heating, and then delivered to a hopper 12 whence they fall into the sifter 16 which comprises a vibrated sieve having two sizes of mesh, or other suitable device such as a rotating perforated cylinder by which the finer particles are removed, the remainder flowing into the hopper 24. The particles, either from the hopper 24 or from a hopper 32 are passed through a constant-level bath 28 of coating material such as emulsified bitumen, which is circulated by pumps 36, their movement being assisted by paddle-wheels 40. They are then removed by a bucket conveyer 46, the buckets 50 of which are made with mesh, perforated or like open lower and side portions, a drain shoot 52 returning superfluous liquid to the bath 28. The granules are deposited in one or more drying chambers 54, heated by gas, electric heating elements 56, hot air or other means or through which a stream of cold air is passed; they are fed forward by a travelling conveyer, and agitated as by a spiral rotor 60; alternatively a vibrated, heated metal plate may be used, or the drying may be carried out continuously or discontinuously in perforated metal drums rotating in a closed chamber heated as by hot air, hot moist air or steam. The dried granules fall on to a perforated vibrating bed 82 which is cooled as by blowing air through it, and are collected through a hopper. The granules may be used to form a structural cellular mass as by suspending them in a wet cement or cement and sand mixture, to which calcium chloride and air-entraining or foaming substances may be added; or they may be spread on a support and grouted with the wet mixture. Expansion joints or blankets can be made by compressing them between sheets of paper, card, foil or the like.ALSO:Cork granules having a flexible moisture-proofing coating are made by treating the granules with a moisture-proofing liquid and drying them, the liquid penetrating a short way into the surface of the granules during drying. The granules may be baked or carbonised before treatment and the liquid may be emulsified bitumen. The granules may be used to form a structural cellular mass as by suspending them in a wet cement or cement and sand mixture, to which calcium chloride and air-entraining or foaming substances may be added; or they may be spread on a support and grouted with the wet mixture.