Patent GB-291670-A (GB)
Title: Improvements in apparatus for sand blasting metal sheets and plates
IPC: B24C3/12
Filed: 1927-10-27
Abstract: 291,670. Haddan, R., (Blast Co. Corporation). Oct. 27, 1027. Sand-blast.- Apparatus for removing scale from, or cleaning metal plates and sheets consists of abrasive impacting devices having nozzles operating on both faces of the sheets which are passed through the apparatus, the nozzles being reciprocated across the path of travel of the sheets. The apparatus consists of a casing 10 in which is mounted a hopper 15 to contain abrasive particles of sand, steel &c. and having a discharge slot 17 which may be closed by a gate 20 and the opening of which may be adjusted oy plates 26 adjustable by bolts 29; the abrasive after use falls into a hopper 31 and thence into a screw conveyer 35, which moves it into a vertical conveyer 45 whereby it is lifted to a spout 56 and discharged into the hopper 15. Particles of scale are removed from the hopper 15 by a blower 57, the inlet 58 of which opens to the hopper; the hopper may be emptied by a gate 60 which on being moved to the position shown in Fig. 1, discharges into a pipe 61. The upper impacting devices 18, Figs. 4 and 5, consist of a body 68 having a central bore 69 and having shaft portions 71, 72, through one of which 72, air is supplied. A trough 75 is provided on the body 68 to receive abrasive from the spout 17, and the abrasive passes to nozzles 85 whence it is blown by jets 82 provided with valves 87. The lower impacting devices 19 are similar to the upper, having shaft extensions 96, 97 and the abrasive being fed thereto by spouts 122 discharging into a trough 107. In order to reciprocate the impacting devices, the shaft extensions 71, 96 extend through the wall 13 of the casing 10, and have squared parts 126 which are guided by rollers 135 carried by supports 129 adjustable in a frame 127; by adjustment of the supports about the axis of the shafts, the angle of the nozzles, with respect to the sheets being cleaned, may be changed. The shafts have shouldered ends 154 engaging extensions 149 of frames 147 having slots 148 engaged by blocks secured by cranks 159 to discs 160 driven through gearing from a motor; adjustable dash-pots 188 are provided to cushion the movements of the impacting devices. To prevent escape of abrasive through the walls 13 around the shafts, each wall has an opening 174 in which is arranged a pleated leather &c. sheet 176 secured to the shafts by clamps. The sheets are fed through the apparatus by rolls 200, 204, 223, 227 driven by a chain 232 which also drives guide rolls 211, 214, 217, 220, and injury by abrasive to the drive of the rolls is prevented by the use of vacuum hoods 264, 270, 273, 278, 288 connected to a pipe leading to a suction device; stop-doors 292 of leather and steel press against the guide rollers to minimize the passage of abrasive towards the inlet and outlet ends of the apparatus. Side plates 298, 300 are provided to guide the sheets and to take up wear. Adjacent the outlet side of the apparatus, a brush 302 is provided to remove abrasive from the sheets, the brush being pivoted at 304 and connected with springs 311, 312 by an arm 306. The upper surface of the sheets is brushed by brushes 376 carried by a belt and noved across the sheets, two sets of such brushes being provided, travelling in opposite directions across the sheets. The sheets are fed into the apparatus from a platform 390 supported on screws 392 driven from a motor 399 so that successive sheets are fed from a constant level into the apparatus, and therefrom on to a platform 409 which also may be lowered and raised.