GB708277A - Improved method and apparatus for producing fibers from glass - Google Patents

Abstract

708,277. Glass fibres. OWENS-CORNING FIBERGLAS CORPORATION. June 25,1961 No. 15059/51. Class 56 Glass fibres are formed by feeding a glass filament P into one side of a gaseous blast formed of the products of combustion and in proximity to the source thereof, the blast having a temperature sufficient to soften the glass and a velocity sufficient to draw the softened glass into fibres, and maintaining the temperature of the blast above the softening temperature of the glass for a substantial part of the length of the blast by flowing a gaseous medium over the blast to decrease the heat loss to the surrounding atmosphere. As shown in Figs. 1 and 3 a gaseous mixture is fed to a burner 19 having a refractory body 20 and a combustion chamber 21 which terminates at one end in a perforated wall 22 and at the other end in a restricted outlet 23. The body may be surrounded by a sheet metal shell 20a which forms an inlet chamber beyond wall 22 communicating with the fuel conduit 26. The relation of the cross-sectional areas of outlet 23 and chamber 21 is suitably 1 : 8 to 1 : 4. Glass flowing through orifices 28 is attenuated by rolls 29, 30 into filaments P which are fed into the blast by means of a guide 32 comprising a plate 33 having spaced grooves 34 to receive the filaments, extending downwardly in juxtaposition to the front burner wall, and terminating flush with the top of outlet 23. Two injectors 40 are secured on the front wall of burner 19 above and below outlet 23, and each comprises an elongated chamber 41 having an enlargement 42 at one end to communicate with a source of gaseous medium through conduit 43, the gas being discharged through orifices 44 to the opposite sides of the main blast B at a much lower velocity than that of blast B. The gas from the injectors is carried along by the blast B as at 45 and is eventually ignited by the blast to substantially increase the width of the blast as at 46. The distance from the burner at which this ignition takes place may be varied by using a raw gaseous mixture or one mixed with air, added air expediting the ignition and increasing the temperature. Streams S of molten glass are carried away from the filaments P by the blast and attenuated, the extended attenuating length of the blast resulting in finer fibres. Combustion products may be discharged towards the blast instead of combustion gases, thus in Fig. 4, a pair of burners is supported on the front wall of the main burner 19 above and below the outlet 23, leaving a space 51 for feeding the filament. Each burner 50 comprises a combustion chamber 51a with fuel inlets 53 and outlets 52 adjacent the front wall of burner 19 for the combustion products. The distance between the inner walls of burners 50 is greater than the width of opening 23, forming a continuation of the throat of burner 19. The temperature of the combustion products from burners 50 may be increased by adding oxygen to the gases burned. The outlet 52 of the lower burner is opposite the filaments at the zone where the filaments are introduced to blast B, ,thus the combustion products from burner 50 increase the depth of the blast B in this zone, and prevent the filaments passing through the blast without melting. In the apparatus shown in Fig. 6, a single supplementary burner 66 is supported below the outlet of burner 19 with its outlet 67 directed toward the underside of the blast. The rate at which the supplementary gas is introduced to the blast also exercises some control of the turbulence of the blast at the attenuating part, the turbulence of the blast having a salutary effect on the rate of fibre production. Specification 590,258 is referred to.