Patent GB-1429580-A (GB)
Title: Purification treatment process and apparatus
IPC: D04H1/4209
Filed: 1974-10-03
Abstract: 1429580 Reducing pollution in making resin-fibre mats SAINT GOBAIN INDUSTRIES 3 Oct 1974 [10 Oct 1973] 42998/74 Heading D1R In the production of a bonded fibre mat 23 pollution is reduced by recycling waste products by repeated passage through the mat, washing the waste products, purifying part of the waste at each cycle and transferring part of the heat resulting from fibre formation to a fluid which is then cooled. Glass fibres are produced by introducing molten material 102 into a perforated rotor and drawn downwards by an annular array of high speed hot gas jets. Alternatively the fibres are extruded from spinneret (112, Fig. 13, not shown), by directing a molten glass net (121, Fig. 14, n.s.) upon high speed rotors (123, 124) or by the action of hot gas jets upon glass rods or filaments (115, Fig. 12, n.s.). The drawn fibres are sucked onto perforated belt 15 by blower 19, distribution being achieved by oscillating nozzle 14 or by air pair of compressed air nozzles (14, Fig. 13, n.s.). Binder is applied by jets 13, preferably as an aqueous solution or dispersion of phenol formaldehyde resin, urea-formaldehyde resin, oxidised linseed oil or bitumen. Cooling water is supplied by sprays 50 situated above or below binder sprays 13 and/or below perforated belt 15 to remove the heat produced by fibre formation. (Little or no atmospheric air is drawn in for cooling, c.f. the prior art, Fig. 1, n.s.). The gases drawn through mat 23 are washed by sprays 45, by bubbling through wales in jar (48, Fig. 12, n.s.) or by counter-current contact with thin films of water flowing over dividing walls (46, Fig. 4, n.s.). Heat is also removed. Chamber 16 below the perforated belt may increase in cross section to reduce the velocity of the gas and thus collect particles of solid waste. A cyclonic or electrostatic precipitator 18 proceeds blower 19. Most of the partly purified gas is returned by duct 34 to mat forming chamber 22 and again passes through mat 23. 5% to 10% of the gas is taken to burner 39 where remaining organic impurities are connected to carbon dioxide and water and released to the atmosphere. Duct 35 leading to burner 39 may be situated in chamber 22 (Fig. 4, n.s.). Noise is reduced by absorbing panels 99, 100. The washing water collects at sump 103 and is passed through vibratory mesh filter 51 to remove fibres and insoluble binder. The filtered water is cooled by circulation through heat exchanger 105. Cooled filtered water is supplied via pump 55 to cooling sprays 50, washing means 45 binder preparation 108 and water treatment station 109. As illustrated station 109 comprises a pump 77 which raises the pressure to 16 bar, a heat exchanger 83 which raises the pressure to 80C, a mixer 78 in which superheated steam raises the water to 200C and a reactor 82 in which the treated water is kept for 2 to 4 minutes. The treated water is cooled in the heat exchanger, decompressed, centrifuged at 110 to remove binder insolubilised by the heat and returned to tank 52. In other embodiments heat is applied to the interior of a treatment tank by steam or an immersed burner or electric arc. In other embodiments the dissolved binder is removed by flocculation or bacterial action. The solid waste removed by filter 51 and centrifuge 110 is heated to 600 to 700C to burn organic material and frit the fibres into low volume plates which are returned to the fibre production station, or heated to 1000C to melt the waste fibres.