Abstract: A method of treating flat glass to reduce its vulnerability to scratching, e.g. during storage and/or transit, wherein a transparent film of a cationic surface active agent is adsorbed on the glass by applying an aqueous solution of the surface active agent to the glass on the production line and drying the glass. The solution may be applied to the glass after is has been washed, near the end of the production line, using for example an anionic surface active agent as detergent. Alternatively, a solution containing both a cationic surface active agent and an nonionic surface active agent as detergent may be applied to the glass to wash it, followed by rinsing with water and drying.

Abstract: A structural glass assembly in which one or more glass plates are secured by an attachment device to an adjacent element, the attachment device comprising a plate member partially overlying an edge region of the glass plate on one side only thereof and extending parallel to the plane of the plate so as to form a connection between the glass plate and the adjacent element, the plate member being spaced from the glass plate and secured to the edge region of the plate so as to permit the edge region to flex inwardly or outwardly when subjected to load.

Abstract: Glass is heated to a temperature above its strain point and is thermally toughened by chilling with a quiescent gas-filuidized particulate material which has gas-generating properties and a mean particle size in the range 30 .mu.m to 120 .mu.m, a particle size distribution in the range 1.15 to 2.78, a flowability in the range 69.5 to 92, and a thermal capacity per unit volume at minimum fluidization in the range 0.7 to 1.59 MJ/m.sup.3 K.The invention is particularly suitable for thermally toughening glass sheets for vehicle windscreens.

Abstract: The thermal treatment of glass is effected by contacting the glass, when it is hot, with a gas-fluidized mixture of particulate materials, at least one of which is selected to have gas-generating properties when heated by the hot glass. The materials are mixed in selected pre-determined proportions which impart to the mixture a thermal capacity and flowability which are such that a required thermal treatment is achieved.The method is particularly suitable for the thermal toughening of glass sheets for vehicle windscreens.

Abstract: A process for producing a photochromic glass which will exhibit a brown coloration in its darkened state without a degradation in the photochromic properties of the glass taking place. The process includes the steps of forming a batch of specified components which include tin or a tin compound and subjecting the resultant batch to a series of glass-forming steps so as to develop photochromic properties in a glass article formed from the molten batch.The invention also provides a photochromic glass having silver halide crystals and tin dispersed throughout the glass, the glass having in its darkened state a brown coloration which is described in accordance with the Hunter L,a,b, Color Scale System by the rectangular region having corners defined by the (a,b) co-ordinates: (5,1), (1,5), (12,16) and (16,12), the 1/2 OD FT of the glass being 120 seconds or less.

Abstract: In optical glass fibres formed of high-silica glass which is susceptible to the production of color centers on drawing into fibres, the attenuation due to such drawing-induced color centers is suppressed or reduced by incorporating from 1 to 100 (preferably 3 to 50) parts per million of cerium oxide in the glass from which the fibre is drawn, under oxidizing conditions such that a significant proportion of the cerium is in the form of ceric ions and the total attenuation is not more than 20 dB/Km in the wavelength range from 800 to 900 nm.

Abstract: Alkali-resistant glass fibres for use as reinforcement in cementitious products are formed from a composition comprising, in weight percentages:______________________________________ SiO.sub.2 55 to 75% R.sub.2 O 11 to 23% ZrO.sub.2 6 to 22% Cr.sub.2 O.sub.3 0.1 to 1% Al.sub.2 O.sub.3 0.1 to 7% Rare earth oxides + TiO.sub.2 0.5 to 16% ______________________________________where R.sub.2 O is any one or more of Na.sub.2 O, K.sub.2 O or Li.sub.2 O, the content of TiO.sub.2 does not exceed 10%, and the total of the components recited above amounts to at least 88% by weight of the glass, the glass having been melted under non-oxidizing conditions such that all or a substantial proportion of the chromium in the glass is in the trivalent state.Cementitious products incorporating such fibres, e.g. in a proportion of 3 to 6 weight %, can be made using a Magnani-type asbestos cement machine or by a "spray-up" method.

Abstract: A method of finishing a glass surface to a close tolerance and a substantially blemish-free state using a moving polishing lap and an aqueous treatment liquid containing inert abrasive particles, in which the treatment liquid also contains a bifluoride which reacts with the glass to form an insoluble silicofluoride or fluoride, an acid supplying hydrogen ions and a solubility suppressant which ensures that the silicofluoride or fluoride separates out on the glass surface, whereby the lap and inert particles remove the silicofluoride or fluoride from high portions of the glass surface and thereby allow further reaction and glass removal in those areas until the desired finished form of the glass surface has been achieved, whereupon the supply of treatment liquid is stopped and immediately replaced by a supply of an alkaline neutralizing solution, e.g.

Abstract: The invention provides a method and apparatus for treating articles with particulate material, for example for thermally toughening glass sheets. The particulate material consists of or contains permanently magnetized particles and is subjected to an electromagnetic field which travels linearly through the treatment space and is effective to sustain a dispersion of the particulate material in the treatment space. The article is contacted with that dispersion.

Abstract: Alkali-resistant glass fibres, in the form of continuous-filament for use as reinforcement in cementitious products, or in the form of glass wool, are given enhanced alkali resistance by the incorporation of ThO.sub.2. The fibres are formed from a glass composition comprising, in weight percentages:______________________________________ SiO.sub.2 50 to 75% ThO.sub.2 + ZrO.sub.2 5 to 30% with ThO.sub.2 at least 0.4% R.sub.2 O 0 to 25% R'O 0 to 40% R.sub.2 O + R'O 10 to 40% Rare earth oxides 0 to 20% ______________________________________the content of ThO.sub.2 being at least 1% when the content of ZrO.sub.2 is less than 6% but not exceeding 9.5% when ZrO.sub.2 exceeds 8%, where R.sub.2 O represents Na.sub.2 O, K.sub.2 O or LiO.sub.2, with K.sub.2 O not exceeding 10% and Li.sub.2 O not exceeding 5% and R'O represents one or more of MgO, CaO, SrO, BaO, ZnO and MnO.

Abstract: Apparatus for marshalling glass sheets comprises a conveyor capable of conveying an array of sheets lying in a transverse sheet array across the conveyor to a sheet removal station, transverse conveying means extending transversely above the conveyor and transfer means operable to transfer a sheet or sheets from the conveyor to the transverse conveying means at the sheet removal station. The transfer means includes a plurality of selectively and separately operable transfer devices, such as lifting devices, extending in an array across the array of sheet positions, and control means for controlling simultaneous operation of selected transfer devices.

Abstract: A roll for use under high or low temperature conditions, for example a conveyor roll in a flat glass annealing lehr, comprises a tire of a different material from collars on the roll between which the tire is held. The tire and at least one collar have matching frusto-conical surfaces which are designed so that differential thermal expansion between the tire and the retaining collars causes sliding movement only of frusto-conical surfaces relative to each other.

Abstract: Fast-response photochromic boro-silicate glasses which have a half-fading time of not more than 145 secs, have silver halide crystals dispersed throughout the glass and are free from barium, comprise, in weight percentages:SiO.sub.2 --31 to 59%B.sub.2 O.sub.3 --18 to 28%Al.sub.2 O.sub.3 --8 to 20%R.sub.2 O--6 to 16%wherein R.sub.2 O represents one or more of Li.sub.2 O, Na.sub.2 O and K.sub.2 O in amounts within the ranges 0 to 3% Li.sub.2 O, 0 to 8% Na.sub.2 O and 0 to 16% K.sub.2 O, and where the content of silver, expressed as Ag.sub.2 O, lies within the range 0.05 to 0.4% by weight, while the content of halide lies within the range 0.13 to 1% by weight of the glass.Further optional constituents are MgO (up to 2.6%) and P.sub.2 O.sub.5 (up to 12%). Refractive index n.sub.D can be corrected to the standard ophthalmic value of 1.523 by additions of ZrO.sub.2, TiO.sub.2 and/or PbO.

Abstract: A heating chamber for pellets of glass batch material has a pellet inlet in one wall of the chamber and a pellet outlet at a lower part of the chamber so that a bed of pellets is formed with an upper surface inclined at an angle of repose of the pellets. Hot gas is fed into the bed of pellets through a plurality of outlets arranged in a plane parallel to the surface of the bed so that gas emerging from all the outlets has a substantially constant path length to the surface of the bed.

Abstract: A glass sheet is thermally treated, for example thermally toughened, by heating the glass sheet, and lowering the sheet into a gas-fluidized bed of particulate material which is at a glass-treatment temperature, for example quenching temperature. Extraction of gas from a localized upper region of the bed is commenced prior to the lowering of the hot glass sheet into the bed in order to produce gradually an unfluidized static packed condition of the material in that upper region of the bed. The glass sheet is lowered into the bed at a time after commencement of gas extraction which is such that the lower edge of the sheet passes through that upper region prior to full attainment of the static packed condition.

Abstract: Glass scoring apparatus comprises a cutting tool, means for applying a cutting load to the cutting tool when the tool engages a glass surface to be scored, and a damping member arranged to absorb energy developed by reaction forces opposing the cutting load when the tool is moved into contact with the glass. The damping member has a loss factor tan .delta. which is high enough to prevent any substantial transient reduction in the cutting load.

Abstract: Flat glass is manufactured by the float process and is attenuated to a thickness in the range 1.5 mm to 5 mm. In an attenuation zone of the bath the viscosity of the glass is controlled to regulate attenuation of the float ribbon to a desired width and thickness and transverse barriers are provided on the floor of the tank structure, containing the molten metal along which the ribbon is advanced, to constrain to forward flow the molten metal entrained beneath the ribbon. Upstream counterflow from the cooler end of the tank structure is alongside the ribbon and replenishes the molten metal beneath the ribbon between that transverse barrier and an upstream similar transverse barrier.

Abstract: In a rotary pan pelletizer, a central circular portion of the bottom surface of the pan is raised above the level of the annular portion around this central portion, and a stationary central plough is disposed with its lower surface in close proximity to the raised central portion. Binder liquid is fed on to the raised central portion and in operation the central plough keeps the raised central portion substantially clear of build-up of the material to be pelletized, so reducing formation of lumps and stabilizing operation. Further ploughs or scrapers are disposed over the annular portion to maintain a constant level of build-up of material thereon, at substantially the same depth as the height of the raised central portion.

Abstract: A glass sheet is thermally toughened by heating the sheet to a temperature near to its softening point and then lowering the sheet into a gas-fluidized bed of particulate material. A void region is established beneath the lower edge of the sheet as it is initially immersed in the fluidized bed.

Abstract: To reduce breakage of fibres in optical glass fibre bundles during manufacture caused by formation of loops in the fibre during sheathing, a twist is imparted to the fibre bundle during its formation. The apparatus of the invention includes a furnace, a retaining member for holding clad glass rods in a predetermined spaced relationship one to the other, a guide member adjacent the furnace for maintaining the rods in said spaced relationship, said retaining member being movable with respect to said guide member and connected to a drive means for passing the rods into the furnace, means for drawing the rods into fibres and forming the drawn fibres into a fibre bundle and means for causing relative rotation of the said retaining member and said guide member with respect to said means for drawing the rods into fibres, so as to impart a twist to the fibre bundle as the fibres are drawn from the rods and formed into the bundle.