Patent GB-904517-A (GB)
Title: Coated glass fibre mat
IPC: D04H1/645
Filed: 1958-12-17
Abstract: 904,517. Bitumen-coated glass fabrics. SCHULLER, W. H. W. Dec. 1, 1959 [Dec. 17, 1958], No. 40802/58. Class 140. A bituminous impregnated and coated glass fibre mat for roofing, or pipe and cable wrapping, is produced by carrying forward a glass fibre mat, to which no binder has been applied, on conveying means, e.g. an endless belt, to the surface of which a dusting material has been applied, in such manner that no tension is exerted on the mat in the movement of the conveyer, a bituminous composition then being applied on the upper surface of the mat so as to seep through the mat to ensure perfect impregnation and coating thereof. The bituminous composition may be applied in a hot liquid condition by spraying, e.g. at 180‹ C.; in cold granular form and then heated and rolled into the mat; or applied to a coating band which is moved relatively to the mat so as to transfer the coating to the mat. The dusting material applied to the upper surface of the belt is maintained at an exact level, any excess material being removed by suction. The binder-free mat may be lightly pre-sprayed with a bituminous composition. The coated product may be cooled by the application of air to the top and/or bottom surfaces of the mat. A dusting material may be applied on the upper surface of the coated mat and the product subsequently further cooled. Excess bituminous composition may be removed from the mat. The impregnated mat, after setting, may be passed between pressure rollers to press the dusting powder into the coating, and excess dusting material may be brushed off. The edges of the mat may be reinforced by the application of staple glass fibre slivers or rovings in or on the surfaces of the mat. The edges of the coated mat may be trimmed by slitting-wheels, or the product may be slit into strips for use as wrapping material. The width of the finished product may be maintained by endless limiting steel belts having spaces between them of predetermined width which may be kept constant by rigid guides. The belt may be cleaned by scraper members which may be heated and inclined at an angle to the movement of the mat, or by a heated roller. The belt may be supported on slide rails of brass or copper, or on a jointed endless belt moving on rollers at the same speed as the belt. Suitable dusting material consists of particulate or pulverulent material such as silica, sand, talc, slate, and mica dust. Apparatus for producing the impregnated and coated glass fibre mat includes means for feeding binder-free glass fibre mat t on to conveying means, means 6 for applying a dusting powder to the belt, and means for applying the bituminous composition on to the upper surface of the mat. The means for feeding the mat t to the belt may comprise an inclined conveyer belt 2 from which the mat passes over a supporting member 3 on to the horizontally disposed belt 4. The composition may be applied by heated spray tubes adapted for movement transversely of the mat, slotted nozzle 10, or a coating band 36 adapted for movement relatively to the mat and means 37 for spraying the coating band with bituminous composition. Scrapers 12, 39, one or more of which may be heated, and suction tubes 11, 38, may constitute the means for controlling the thickness of the applied coating. Preliminary spraying of the mat with bituminous composition is effected by spraying tube 9 which is positioned in front of where the mat is received on the conveyer belt. Cooling means 13, 15 comprising cold air fans are disposed before and/or after device 14 which applies dusting material, and near to where the mat is removed from the belt prior to passage through pressure rollers 16, 17, and brushes 18 to remove excess dusting material. Slitting wheels 19, 20 trim the edges or slit the coated product, the edges being sealed by gas flames 21. A pair of endless belts 26, 27 movable in the direction of the conveying means, are provided, and the space b<SP>1</SP> between the bands is kept constant by guide rails 28, 29 mounted at the side of the belt. Movement of the conveying means is effected by slide rails 32, or jointed endless band 33. Scraper means 24 cleans the belt on its return travel.