GB864446A - Electrostatic separation apparatus - Google Patents

Abstract

864,446. Electrostatic separators. GREENSHIELDS. J. B. June 30, 1959 [Oct. 6, 1958], No. 22360/59. Class 117 [Also in Group XXXV] Electrostatic separation apparatus for separating stalk from tea leaf comprises three metal feeder trays 21-23 arranged in a frame 24 which is secured to the main frame 26 by four leaf springs 27 to enable the frame 24 to move in the directions B. Vibration of the frame 24 is produced by means of a cam 30 driven by a motor 34, and the material to be treated is contained within a hopper 38 of which the outlet gap 54 is controlled by an arcuate plate 49 rotatably adjustable by an arm 53. A number of radially disposed arms 48 are rotatable by the motor 34 and project into the gap 54 through slots in the plate 49. Separator plates 59-61 of electrically insulating material are hinged to fixed hardboard trays 56-58 respectively and may have their angle of inclination adjusted by cords 64 connected to a handwheel 67. Sheets 71, 72 of flexible electrically insulating material are secured to the upper edges of the separator plates. A deflector plate unit 73 includes three metal strips 77-79 electrically connected together and to a generator 95 (see Group XXXV) also driven by the motor 34. Thin films 81 are stretched across channels 74- 76 containing the strips 77-79, and supports 82 for the channels are adjustable by rack and pinion in the directions D; the films, channels and supports are of electrically insulating material. Passage of the mixture of tea leaf and stalk from the hopper is facilitated by an inclined plate 127 secured to the tray 21 and by the action of the arms 48. The leaf, with a proportin of stalk, falls on to the tray 22 via tray 56, and the bulk of the stalk is attracted towards the channel 74 to fall on the sheet 71. Further separation takes place at the plates 60, 61. The electrostatic field may be generated by a transformer and rectifier, and electromagnetic means may be used for producing the vibration.