| 摘要 |
Attenuated fibres of heat-softened mineral material are produced at one or more fibre-forming stations, have an aqueous binder applied to them at the fibre-forming station, and are collected on a moving foraminous collector. Waste binder is continuously removed from the collector by recirculating wash water to which an alkaline detergent is added. Some of this wash water is diverted for use in the binder composition, for which purpose its alkalinity is reduced, and it is mixed with binder ingredients. In the embodiment described, the mineral material is glass and is formed into fibres in each of several rotary apparatus, from which the fibres are attenuated by and entrained in a blast of gas which carries them to a foraminous conveyor belt beneath which is a suction box. The gas from this suction box is washed by a spray of water. The return run of the conveyor belt is also washed by water. The water from both of these washing operations together with water draining from the material on the conveyor and any binder and fibres entrained therein are passed through a screen to a tank where are added sufficient fresh water to maintain a constant volume and sufficient barium hydroxide to maintain a constant alkalinity. The water in this tank is heated and recirculated by pumps to both washing points. Part of it is also circulated to another tank, maintained at constant level by an overflow, where it is cooled. It is drawn off as required from this tank to a mixing vessel where it is mixed with ammonium sulphate, to reduce the alkalinity and precipitate barium sulphate, and with ammonia, resin and oil to form the binder composition. When there is more than one fibre-forming station, the rate of flow of binder to a binder applicator associated with each may be independently variable, to give a varying distribution of binder through the thickness of the product, e.g. to give a low binder content near each surface and a higher binder content in the middle of the mass. |
