GB1266739A - - Google Patents

Abstract

1,266,739. Electrostatic powder sprayer. NIKKA K.K. 18 Dec., 1969 [27 Dec., 1968], No. 61660/69. Heading B2F. A high tension discharge powder sprayer as shown comprises an elongated main body 10, a powder box 40 separated from the main body 10, a roller 17 mounted rotatably in the main body 10 between left and right holders 11 and 12, with an insulated electric wire 18 stretched close to the roller 17, and a high tension generator to supply a high tension to wire 18 to produce a corona discharge. Upper and lower doctor blades 15 and 16 are fixed to upper and lower plates 13 and 14 and are lightly in contact with the roller 17; and together with the holders 11 and 12, these form a space 20. A U-shaped enclosed passage is formed by bore 23 in holder 12, the space 20, a cut-out portion 24 in lower plate 14, an elongated hole 25 made through plate 14 communicating with portion 24, and a bore 26 in holder 12. Powder is delivered from box 40 by delivery device 50, which comprises a pipe 55 secured between a connector 51 in the powder storage chamber 42 and a connector 53 in bore 23. Pipe 56 is connected in a similar manner. Two helically wound wire coils 57 and 58 having a fixed pitch are provided in the pipes 55 and 56, and connected to connectors 61 and 62 which are fixed to rotary shafts 59 and 60. Coils 57 and 58 act as a flexible feed screw and return screw respectively, so that powder is fed and returned in the direction of the arrows on Fig. 2; both coils rotate at the same speed, but the pitch of coil 58 is greater than that of 57, thus obviating clogging of the powder sprayer. The roller 17, which has notches on its surface, is rotated, and when the powder in the notches is carried near wire 18, it is blown down by an ion wind generated by high tension discharge between the. wire and roller, onto the surface being treated, as a uniform spray. Doctor blade 16 removes any excess powder from the roller.