Patent GB-997072-A (GB)
Title: Improvements in and relating to the manufacture of objects formed of mineral fibres
IPC: B29C33/36
Filed: 1964-02-24
Abstract: 997,072. Moulding resin-impregnated fibres. COMPAGNIE DE SAINT-GOBAIN. Feb. 24, 1964 [Feb. 26, 1963], No. 7605/64. Addition to 986,203. Heading B5A. [Also in Division F2] In a process according to the parent Specification, e.g. for making insulating cylinders for pipes, the resin-impregnated felt which has been heated to gel the resin and bring it to the plastic polymer state is subjected to pressure to increase the specific density of the felt which is then wound on a mandrel for forming the felt to the required shape. In one embodiment (Fig. 2), the strip of felt (glass fibres) coming from a drying tunnel is carried through ovens along a conveyer band 29 towards the rigid section manufacturing apparatus which is enclosed in an oven (not shown). The front edge of the strip passes a photo-electric cell 32 which actuates automatic contacts to initiate the following operations: The front extremity of the strip passes under calendering rollers 30 which are not lowered and is taken up by a perforated mandrel 35 under vacuum therein. During winding, a counter roller 49 descends progressively under the effect of jacks 53. After formation of the first turns pneumatic jacks 34 act on calendering rollers 30 to press them against the band of felt, and winding round mandrel 35 continues, counter roller 49 exerting a pressure to give the felt the required final density. The speed of rotation of the mandrel is varied by the action of a cam 65 on lever 74 which acts on a variable speed gear 46 so as to maintain the linear speed of the felt constant. At the finish of the winding a limit contact operated by a plate 75 stops the cam 65, raises calendering rollers 30, and disconnects the coupling 61, and coupling 56 which ensures the rapid lowering of counter roller 49 to exert a slicking action on the felt. When the counter roller 49 ceases to be in contact with the rigid section, a contact operates spacing of points 36 by jacks 48, and operates a coupling 83 to raise the racks 76, raising the mandrel by means of forks 77 until a limit switch disengages the coupling 83. The mandrel is removed by rails 84, the articulated part 88 of one of the rails operating a switch for the lowering of the racks. In descent the racks stop for the introduction of an empty mandrel which is fed by rails 90, pins 91, 92 ensuring their separate distribution. In a second embodiment (Fig. 3), the felt is fed along a conveyer band 100 and is wound on a mandrel 106 under vacuum in the latter, the mandrel 106 being supported by one of the spokes 107 of a carrying wheel. After the first turn, calendering rolls 102 are lowered, compressing the felt, and winding continues under rotation of a counter roller 109 which gives the felt the required density. When the section is formed, the carrying wheel is rotated to bring a new mandrel 106a to form a new section, the full mandrel coming into contact with another counter roller 113 to smooth the surface. On further rotation of the carrying wheel, the mandrel is removed by rails 117 to a conveyer 118. An oven 121 surrounds the device.