Method and apparatus for depositing nonconductive material onto conductive filaments

摘要

An electrostatic filament coater comprising a plurality of coating chambers arranged coaxially in spaced apart serial relation. Each of the coating chambers has a base and an apex and being generally frusto-conical in shape with an exit opening at the apex and an entrance opening at the base. All of the coating chambers except the last one are positioned with the apex being within the base of the next adjacent coating chamber. The filament is trained through the coating chambers. A plurality of electrodes are positioned within the coating chambers so as to surround the filament. A near arc-over voltage is supplied to the electrodes and a fog of particulate coating material suspended in a gas is passed through the coating chambers and axially of the filament at a velocity which results in the electrostatic deposition of the particulate matter on the filament and the exhaust of the gas and excess particulate matter from between the coating chambers and the apex opening of the last coating chamber. The method of the invention includes the steps of passing a filament through a cloud of particulate coating material suspended in a gas, surrounding the filament with a plurality of spaced apart electrodes, imposing a near arc-over potential to the electrodes and imposing a near arc-over potential to the electrodes to electrostatically deposit the particulate coating material on the filament.