GB1229282A - - Google Patents

Abstract

1,229,282. Coating apparatus. RANSBURG ELECTRO-COATING CORP. 15 July, 1968 [14 July, 1967], No. 33656/68. Heading B2L. Electrostatic coating apparatus comprises a plurality of devices for discharging particles of coating material, charging electrode means associated with said discharge means, means for establishing an electrostatic charging field between said devices and an article to be coated, and means for establishing an electrostatic reference potential for said charging field between adjacent discharge devices and at a voltage lead substantially different from that of said discharge devices and electrode means. Articles 12 to be coated are suspended from a conveyor 10 connected to an earth 11. Metallic spray guns 15, 16, 17 having respective charging electrodes 15a, 16a, 17a are mounted on a metallic bar 14 insulated from and arranged to reciprocate on a bar 19. Bar 14 is connected to one terminal of a high voltage generator 18, the opposite terminal of which is earthed. Auxiliary electrodes 20, 21, consisting of high tension cable with the conductive core bared at the face ends, are carried by bar 14 at positions between guns 15, 16 and 16, 17 respectvely. The core ends are substantially aligned with the charging electrodes. Similar auxiliary electrodes 26, 27 are carried by bar 14 outwardly of guns 15 and 17 respectively. The auxiliary electrodes are connected to earth via respective resistors 24, 25, 28, 29 to establish the auxiliary electrodes at an intermediate potential for modifying the electrostatic field to improve the percentage of the coating material discharge which is deposited on the article to be coated. Bar 14, if insulated from the guns, may be used with an appropriate potential upon it to modify the electrostatic field.