Abstract: The present invention is directed to a concrete roof tile having a front edge surface, which is that surface of the tile across the width of the tile and which faces downwardly when in use on a roof. The front edge surface has a progressively greater depth as between a relatively thin profiled central portion and thicker profiled side portions. In use, the horizontal rows of the roof tiles are laid in half-bond relationship with adjacent horizontal rows to give a pleasing appearance in which the combined overlapped thicknesses of the tiles in one such row of tiles and the tiles of adjacent rows of tiles above and/or below at overlapped headlap and tail portions are the same or substantially the same.

Abstract: A conveyor-collator assembly for use in forming stacks of articles, e.g. concrete roof tiles (T) at speeds of up to 200 tiles per minute, is provided with a conveyor means (42) by which tiles (T) are fed seriatim to a velocity control means (72) whereby each tile (T) is transferred under "no-load" or substantially "no-load" conditions onto a falling shelf conveyor (140). Tiles (T) held in the conveyor (140) are thereafter deposited onto a support (26-28) of a stack forming means (24) under "no-load" or substantially "no-load" conditions whereby breakages of tiles (T) due to "shock loads" experienced hitherto in prior art arrangements is eliminated.

Abstract: The invention relates to a silicate compound having at least one alkaline oxide and silicon dioxide-containing amorphous binder matrix and also containing oxides from the aluminum, calcium, titanium, magnesium, zirconium, and/or boric oxide group. To provide a silicate compound which is suitable for both making a moulding and coating a substrate, resistant to effects like weathering, especially through alternate frost and thaw, and attack by acids, lyes or fouling, it is proposed that the amorphous binder matrix contain 4 to 25 mol silicon dioxide per mol alkaline oxide, the alkaline oxide being lithium, sodium, and/or potassium oxide and the amorphous binder matrix also contains up to 80 mol aluminum oxide and/or up to 45 mol calcium, titanium, magnesium, zirconium, and/or boric oxide evenly distributed per 100 mol silicon dioxide.

Abstract: A roof tile making machine and its method of operation. The reinforcement ribs on the underside of a concrete roofing tile are formed during their manufacture by directing mortar into recesses in a pallet on which the tile is made, with a compactor means in the form of multi-tined wheels compacting the mortar in the recesses, and providing thereafter a secondary layer of mortar over the compacted reinforcement ribs, to complete the tile in a conventional manner. A tile provided by the apparatus of the invention has reinforcement ribs which are compacted to the same degree as the remainder of the tile, thereby ensuring that the finished product, when cured, has a uniform, or substantially uniform, strength.

Abstract: An uncured cementitious dough or paste, which is substantially free of particulate components having a diameter greater than 100 microns, said paste comprising in admixture;(a) At least one hydraulic cement;(b) at least one polymer latex, the polymer being present in an amount of 1 to 20 parts by weight per 100 parts of the cement;(c) total water in an amount from 8 to 20 parts by weight of water per 100 parts by weight of cement.A cured cementitious composition may be produced by heating said dough or paste at a temperature of above 100.degree. C. and may be used for products such as roofing elements, for cladding the exterior walls of buildings and other building products.

Abstract: An uncured cementitious composition comprising in admixture:(a) at least one hydraulic cement;(b) at least one reactive water-soluble polymer which is capable of providing a viscous solution in water at low addition levels;(c) water in an amount of from 10 to 25 parts by weight of water per 100 parts by weight of the cement; and(d) a water soluble cross-linking agent capable of effecting chemical cross-links between molecules of the said polymer in the presence of the cement and water.

Abstract: A board of sandwich construction which comprises two outer preformed support membranes consisting of or comprising fibrous material, the said membranes having interposed therebetween an aerated intermediate layer comprising at least 70% by weight based on the dry board of an unfired clay which contains less than 20% by weight of expandable minerals and the intermediate layer also including fibres therein.The boards of the present invention are intended mainly for use as plasterboard substitute.

Abstract: A vortex combustion furnace (1) for the production of glass beads or the like is generally cylindrical and has an outlet flue (24) at its upper end. A burner (13) at the lower end burns a gas/air mixture. Secondary air is introduced into the chamber through tangential air inlets (16) and creates a vortex (71) within the chamber. Tertiary air is introduced through a ring of angled nozzles (71) surrounding the burner further to swirl the flame. The vortex has a top-hat temperature profile with a central heating region with a temperature in excess of 1000.degree. C. and a surrounding cooling region with a temperature not much above ambient. Glass cullet is supplied to a fluidized bed (53) and then entrained in a pipe (44) to be injected into the chamber. The cullet follows a spiral path in the vortex, is heated, melts to form glass beads, is then cooled and finally is collected after striking the wall of the chamber.

Abstract: A vortex combustion furnace (1) for the production of glass beads is generally cylindrical and has an outlet flue (24) at its upper end. A burner (13) at the lower end burns a gas/air mixture. Secondary air is introduced to the chamber through tangential air inlets (16) and creates a vortex within the chamber. The vortex has a top-hat temperature profile with a central heating region with a temperature in excess of 1000.degree. C. and a surrounding cooling region with a temperature not much above ambient. Glass cullet injected into the chamber follows a spiral path in the vortex, is heated, melts to form glass beads, is then cooled and finally is collected after striking the wall of the chamber.