GB1075404A - Electrostatic tablet coating apparatus - Google Patents

Abstract

1,075,404. Electrostatic coating apparatus. TANABE SEIYAKU CO. Ltd. and Z. TAKASONO. June 18, 1964 [June 19, 1963], No. 25314/64. Heading A2A. [Also in Divisions A5, B2 and B8] In coating medicinal tablets electrostatically, the tablets 100, Fig. 1, which may be circular and in the form of pills or capsules, are fed, from a hopper 12, on to the upper run of an endless travelling conveyer belt 10. The tablets are thus conveyed in rows, and are equally spaced apart in each row. Finely distributed particles of a solution of a coating substance or composition, issuing from an atomizer or spraying device 13, are charged in an electrostatic field, created by a highvoltage grid 19, and deposited on the upper sides of the tablets. The half-coated tablets are dried by a device 14, e.g. an infra-red heater. The rows of tablets are then transferred into corresponding channels in a downwardly inclined shoot 32, Fig. 2, and slide into corresponding pockets 26, each receiving an individual tablet, arranged in the periphery of a revolving cylindrical rotor 15, enclosed in a. cylindrical casing 28. The rotor, after turning through 180 degrees, delivers the tablets, from the pockets 26, into corresponding channels in another shoot 33, from which they are deposited, with their uncoated sides uppermost, on the upper run of a second endless, travelling conveyer 10<SP>1</SP>. The said uncoated sides then receive a coating of the coating solution issuing from an atomizing or spraying device 13<SP>1</SP> electrostatically charged by a high-voltage grid 19<SP>1</SP>. The grids 19 and 19<SP>1</SP> may be maintained at a potential between 70 and 100 kilovolts. The completely coated tablets are dried by a device 14<SP>1</SP>, e.g. another infra-red heater, and discharged into a receptacle 43. The lower runs of the conveyers 10 and 10<SP>1</SP> may pass over and under guide rollers 18 and 18<SP>1</SP>, immersed in washing liquid, contained in tanks 20 and 20<SP>1</SP>. Brush rollers 21 and 21<SP>1</SP> may assist in removing the coating substance or composition from the lower runs of the belts.