Patent GB-1267670-A (GB)
Title: Process and apparatus for the manufacture of fibres from thermoplastic materials
IPC: C03B37/05
Filed: 1969-03-12
Abstract: 1,267,670. Glass fibre manufacture. COMPAGNIE DE SAINT-GOBAIN. 12 March, 1969 [14 March, 1968; 10 July, 1968], No. 12969/69. Heading C1M. Production of glass or like fibres is effected by (a) forcibly and continuously projecting the molten glass or like material in the form of a jet or jets against the moving outer lateral wall of a moving body; (b) entraining the molten material on the outer lateral wall in the form of a layer; (c) providing or creating a plurality of separate detachment points in the layer of entrained material; (d) detaching entrained material from the detachment points in such manner as to form primary filaments and (e) attenuating the primary filaments to fibres. As shown in Fig. 2, a rotor 1 on a vertical axis 2 with detachment points 4 on the outer surface 3 has a jet 7 of molten glass projected on to it and the resultant filaments 9 are attenuated by the blast 6 from an annular blower 5. In this embodiment, the jet 7 is formed by a stream 10 of molten glass impinging on a rotating disc 11. In variations of this, as in Fig. 15, the jet 7 may pass through a tuyÞre 16 used to focus the jet which should be at such speed that it wets the whole wall height or it be oscillatable as shown so that the jet 7 impinges narrowly over the whole height of the surface 3. The tuyere may be water cooled by a surrounding jacket. A focusing blower may replace the tuyÞre. The disc 11 may have a profiled shape to give a surface of impact of varying shapes. In place of the disc 11, the stream 10 of molten glass may be directed into jet 7 by a high speed jet of gas (23) and this may be directed through an oscillating tuyÞre (24) or a fixed tuyÞre (26) which oscillates the gas flow by fluid acting through ports (27), (27a) in the tuyere. As a further alternative, a vibrator anvil (28), which may be cooled, has a sloped projecting surface and the speed of the reflected jet 7 can be controlled by adjusting the frequency and amplitude of the vibrator. In addition to the attenuating blast 6, an annular blower may be used for assisting in the collection of the fibres. Such blower is also used when attenuation of the filaments to fibres is effected solely by centrifugal action, soft flames being played on the filaments to maintain them at the required temperature. The inside of the rotor may be cooled. As shown in Fig. 21, a number of jets 39 may be projected on to the surface 3 by using reflectors 40, three streams 38 of molten glass being projected from a rotating disc 37 on the same axis as the rotor 1. In modifications, the axis of the rotating disc is spaced from that of the rotor 1, in one case with parallel axes and in the other, with perpendicular axes, that of the rotor being horizontal. As shown in Fig. 30, the moving body comprises a continuous band- 77 rotating round rotating bodies 78 with jets of molten glass impinging on band 77 at 80, 81, the filaments 82 beginning to be projected as the curvature increases at 83. The blower 79 is in two parts. In a variation, a band (70) rotates round three bodies (71) with three jets of molten glass and the three blowers (72) extend only around the curves of the band (70) over the bodies (71). In this case, and in an embodiment with a single rotor, the blowers (72) and (44) have a decreasing section to assist uniformity of the fibres due to varying thickness of the filaments. The detachment points 4 (Fig. 2) may consist of sharp projections which may be triangular or diamond-shaped or as in Fig. 33, may be produced by temperature variations, the wall 62 being provided with cavities 61 which, with cool inner surface 66 provide " hot spots " 67 from which the filaments 68 are detached. Alternatively, the cavities may extend from the inner wall, giving " hot spots " between the cavities. Apertures extending right through the wall may be used, air pressure in the rotor being such that air may or may not actually pass through the apertures.