Patent GB-882022-A (GB)
Title: Improvements relating to machines for spraying asbestos or the like
Inventor: MOODY BRYAN
IPC: B05B7/14
Filed: 1958-05-30
Abstract: 882,022. Mineral fibre spraying machines. ROBERTS Ltd., J. W. May 25, 1959 [May 30, 1958;June 17, 1958], Nos. 17361/58 and 19370/58. Class 93 [Also in Groups IX and XXX] A machine for forming asbestos or other mineral fibre into a suspension in air and spraying it on to a surface comprises a hopper for the fibre with a bottom opening, two or more toothed feed rollers adapted to engage the fibre, draw it downwardly and drop it into an air space, a toothed roller above the feed rollers working at a lower peripheral speed than those rollers for loosening asbestos to pass to the feed rollers, the rollers being so spaced apart that they do not intermesh but together serving when they are stationary to support the mass of fibres in the hopper, and means in the air space for breaking up clots of fibre which have passed between the rollers. As shown in Fig. 1, the hopper 1 of rectangular cross-section supports three rotatable rollers 6, 7 and 8 carrying spikes 9, the end spikes being inclined outwardly to work near the hopper walls. The roller shafts project outside the hopper and carry sprockets interconnected by chains, the speeds of rotation of the rollers 6, 7 and 8 being in the ratio 3:1:2. Below the rollers is an inverted V-shaped surface 12 arranged at such a height that any clot drawn down between the rollers 6 and 7 cannot readily pass between the left-hand side of the surface 12 and the spikes 9 on the roller 6. There is a similar trapping action on clots between the right-hand side of the surface 12 and the spikes on the roller 8. The surface 12 also arrests small flocks of asbestos that fall between the rollers when the apparatus is temporarily not in use. Below the surface 12 is a rotating drum 14 carrying radial vanes 16 running parallel to the axis and also end radial vanes 15, the vanes 16 flinging the fibre towards the metering cylinder 17 rotating in the same direction as the drum 14 and carrying spikes 18. The fibre is stripped from the cylinder by the brush 19 rotating in the opposite direction to the cylinder at a higher surface speed, and the stripped fibre is sucked as a suspension through a tube 20 by a fan 21 to a spraying nozzle. An adjustable steel comb 22 combs the fibre as it is revolved on the cylinder 17. The rotating parts are driven by a variable speed electric motor 24, a gearbox being provided so that the speeds of rotation of the rollers 6, 7 and 8 may be altered without alteration of the speeds of rotation of the parts 19, 17 and 14, and vice versa. As shown in Fig. 5, the vaned cylinder 14 throws the fibre on to an endless conveyer belt 32 carrying spikes 34, and the fibre layer carried thereby is evened by the rotating brush 37 and is stripped off, to fall into the suction inlet of a fan 36 delivering the fibre to a nozzle, by the stripping brush 35. In a modification, the endless band is replaced by a rotary drum with a spiked surface. In a further modification, the fibre pulled by the rollers falls on to a disc rotated about a vertical axis and having radial projecting ribs on its upper surface. The outwardly-flung fibres are sucked downwards through an annular gap surrounding the disc by a coaxial fan impeller, and are delivered to a spray nozzle. Specifications 617,468 and 844,788 are referred to.