GB1178390A - Screens. - Google Patents

Abstract

1,178,390. Cleaning screens. COAL INDUSTRY (PATENTS) Ltd. 21 July, 1967 [26 July, 1966], No. 33507/66. Heading B2H. A vibratory screen 1 is cleaned by means of a wiper blade 12 mounted for movement along an endless guide way 7 and movable across and in contact with the upper surface of the screen in the direction of travel of the material passing along the screen. Two or more wiper blades 12 spaced around the guideway 7 are interconnected by a rope 10 carried on pulleys 9 at each end of the guide way. The latter consists of a pair of parallel guide rails 7 each having upper and lower rails 7a, 7b interconnected by a semi-circular rail part 8. Each wiper blade 12 consists of a blade proper 16 formed of a flat flexible polyurethane strip secured to a holder 15 mounted on a bracket 13 carrying pairs of rollers 14a, 14b adapted to run above and below the rails respectively. In operation, as the material remaining on the upper surface of the screen is carried along by the vibration of the screen, it bears against the blades 16 in contact with the screen and urges them along the guide rails 7b in the direction of its movement along the screen. As each blade reaches the output end of the screen it is carried by the rope 10 upwardly and along the upper guide rails 7a in an inverted position to be returned to the input end of the screen. Alternatively, the blades may be positively driven, e.g. by an electric motor driving one of the pulleys; they may be supported independently of the screen frame; they may have slotted holes for attachment to the blade holder so that the blades can be adjusted relative to the blade holder to compensate for wear of the blades.