GB856407A - Apparatus and method for preheating cementitious insulating material for moulding - Google Patents

Abstract

856,407. Moulding cementitious insulating materials. FIBREBOARD PAPER PRODUCTS CORPORATION. July 20, 1959, No. 24811/59. Class 87(2). An aqueous slurry of a light weight porous cementitious insulating material is preheated substantially to the point of incipient thickening in a resiliently supported container 12, preferably made of flexible material e.g. rubber, before its introduction into a mould 26. Steam introduced into the slurry through a pipe 13 causes the container to vibrate gently while the mass of the slurry remains relatively stationary. The inner wall of the container is coated so that the cementitious material does not adhere to it, and the preheated material is discharged from the container through a freely suspended clamping valve 21. The various ingredients of which the cementitious material is composed are fed from a plurality of vessels 2, 3 to a mixer 9, which is vibrated to avoid reaction taking place. The resultant slurry is carried to the container 12 by a travelling container 11. When the steam has raised the temperature of the slurry sufficiently it is shut off by the actuation of a switch by a thermo-couple 19 and the valve 21 is opened, the slurry then flowing through a rubber conduit 22 into a hopper 23, which previously has been positioned over the mould, and then into the mould cavities 24 when pistons 27 are lowered therein. Reciprocating fingers 28 follow the pistons 27 with a limited but rapid reciprocating movement and orient the fibres and crystals in the slurry. The mould is heated by hot water circulation through pipes 29, 31. The slurry sets to a self-sustaining mass of insulating material which is ejected from the mould by the ascent of the pistons 27. As shown in Fig. 2, the preheating container 12 is clamped to a frame 16 at its top, by clamps 14, and hangs freely with a resilience which allows vibration. The steam pipe 13 ends in a double nozzle 36, comprising a wider angled outer cone and a narrower angled inner cone between which steam flows in a manner tending to dislodge any material which accidently becomes preset in the passage. The valve 21 comprises members 42, 43 which, to shut the valve, are moved towards one another to clamp the rubber conduit 22 and are suspended by wires 41 so that the vibration of the container 12 is unrestricted. Examples are given of suitable compositions of cementitious materials, one including crystals of magnesium carbonate trihydrate and another including calcium oxide and diatomaceous earth, suitable temperatures, steam pressures and preheating times being specified.