Abstract: In the production of glass fibers by the use of a multi-tipped bushing arranged beneath an opening in the floor of a fore-hearth along which the molten glass flows, an apertured cover plate is disposed across the opening at or near its bottom and carries an upwardly extending duct connecting the aperture in the cover plate with a position in the fore-hearth above the floor and below the normal surface level of the glass, so that molten glass is supplied to the bushing from this position, where the glass is uninfluenced by cooling effects, and on its way thence to the bushing the glass can only contact the surface of the duct which is kept hot by the molten glass in the floor opening outside the duct. The risk of divitrified glass reaching the bushing and causing breakages is thereby much reduced.

Abstract: A glass article is moulded by supplying a gob of molten glass to a mould, regulating the temperature of the mould and the time of closure of the mould so that when moulding is complete the surface viscosity of the glass is at mmost 10.sup.10.5 poises and the viscosity at the centre of the glass is at most 10.sup.8 poises, rapidly transferring the article from the mould before the surface viscosity exceeds 10.sup.10.5 poises and passing it to a cooling medium where the heat transfer is regulated to cool the article to a temperature such that its surface viscosity is at least 10.sup.12.5 poises. The moulding apparatus may open and drop the moulded article into the cooling medium or a gas jet may be provided to blow the article off a support in the open mould into the cooling medium.

Abstract: A stirrer for stirring molten glass comprises a stirring member for immersion in molten glass, a rotary shaft extending upwardly from the stirring member so that in use the shaft may extend above the molten glass and connect the stirring member to a drive device, a platinum or platinum alloy hollow casing surrounding the rotary shaft in spaced relationship thereto, the casing terminating above the stirring member, and separate inlet and outlet means in the casing for introducing and removing a flow of inert gas through the space between the casing and the shaft.

Abstract: Apparatus for detecting and reducing bowing of a rotating roll used with hot material comprises a proximity sensor mounted adjacent the surface of a roll or of a member attached thereto, and arranged to generate an electric signal which varies between maximum and minimum limit values during each revolution of the roll in dependence on any bowing of the roll, cooling means for selectively cooling parts of the roll and a bowing detection circuit arranged to receive the electric signal and provide an operating signal when the electric signal varies by more than a predetermined amount from one of the said limit values, and actuating means arranged to respond to the operating signal and operate the cooling means to cool a required part of the roll to reduce bowing.

Abstract: A method of shaping glass to a desired form comprises delivering molten glass on to a porous support member while feeding a gas under pressure through the porous support member from the reverse side thereof, so as to support the molten glass out of contact with the support member on a cushion of gas, allowing the glass to assume a shape approximating to that of the support member under the forces of surface tension, gravity and gas cushion pressure, cooling the glass while thus supported on the gas cushion to a temperature at which it is so conditioned that it can be shaped by contact with a solid surface without any substantial surface damage, and shaping the conditioned glass by a shaping process which involves contact with a solid surface.The shaping process may be a moulding process, which can be carried out either in the porous support member or in a separate mould to which the glass is transferred. The gas, e.g.

Abstract: Molten glass is poured on to a bath of molten metal to form a pool of molten glass on the bath, which pool is held back on the bath surface by a solid member, preferably wetted by the glass, extending across the downstream end of the pool. A ribbon of glass is drawn from a forward flow of molten glass beneath the solid member and the ribbon is rapidly cooled to stabilize its dimensions as it is drawn away from the solid member.The method is suitable for the production of flat glass of thickness in the range 0.5 mm to 10 mm; also the production of glass foil of thickness in the range 0.005 mm to 0.5 mm.

Abstract: Surface modified glass is produced by method and apparatus in which the glass is contacted with a molten body, for example of a molten metal or molten alloy while the glass temperature is such that it can be modified by migration of cations from the molten body into the glass surface. This cationic migration is electrically induced and the molten material is periodically connected as a cathode with respect to the glass for a preset time sufficient at least partially to deoxidise the molten material. Non-oxidising conditions may be maintained in the molten material and the electrical action at the interface between the molten body and the glass while the molten body is connected as a cathode causes reduction of at least a proportion of the cations in the glass surface to produce a metallic dispersion.The invention is particularly applicable to the modification of the upper surface of a ribbon of float glass advancing along a molten metal bath.

Abstract: A cementitious product and production method wherein the product comprises cement with reinforcing glass fibres therein which are coated with a composition which consists essentially of a protective material to reduce deterioration of the glass fibres, the material being a monocyclic or polycyclic aromatic compound which has at least three hydroxyl groups on the aromatic ring, or when a polycyclic compound is employed, on at least one of the aromatic rings. Preferably, the aromatic compound is soluble in a calcium hydroxide solution, and a preferred such compound is pyrogallol. The composition can also contain a film-forming agent such as a polyvinyl acetate of cationic character or a polyethylene glycol of non-ionic character, as well as a linking agent such as a silane.

Abstract: Ophthalmic glass compositions suitable for toughening by the known ion-exchange process have a composition in weight percentages of: SiO.sub.2 58 to 67% Al.sub.2 O.sub.3 4.5 to 8.0% Na.sub.2 O 8.5 to 17% K.sub.2 O 2 to 11% ZnO 0 to 10% ZrO.sub.2 0 to 6.5% TiO.sub.2 0 to 5.0% As.sub.2 O.sub.3 0 to 1% Sb.sub.2 O.sub.3 0 to 1% B.sub.2 O.sub.3 0 to 6%The total of the foregoing constituents amounting to at least 95% of the composition and the balance, if any, being composed of compatible constituents; the composition including an effective amount of either one or both of ZnO and ZrO.sub.2, to promote ion penetration in an ion-exchange toughening process, either one or both of ZrO.sub.2 and TiO.sub.2 being present; the total of Na.sub.2 O + K.sub.2 O being not more than 22%; B.sub.2 O.sub.3 being present when the total of Al.sub.2 O.sub.3 + ZrO.sub.2 exceeds 10%; and the total of ZrO.sub.2 + TiO.sub.2, when TiO.sub.2 is present, being not more than 5.5%. Refractive index n.sub.d is close to the standard value of 1.

Abstract: Apparatus for feeding material to a glass melting tank comprises a batch material feed system and a cullet feed system. A first control unit controls the rate of the batch feed and a second control unit controls the cullet feed rate. One of the control units receives a signal dependant on the glass level in the tank and thereby controls the rate of one feed system in dependance on the glass level. A ratio control unit is provided to adjust the other control unit so the two feed systems operate at a predetermined ratio of feed rates.