System for on-line detection of polyester oil-free silk or less-oil silk

The invention relates to a system for on-line detection of polyester oil-free silk or less-oil silk, a polyester production process flow sequentially comprises the steps of polyester melt conveying, metering, spinneret plate melt extrusion, cooling, drafting setting, oiling, main network and winding, and the system for on-line detection of polyester oil-free silk or less-oil silk comprises an electrostatic recognition device; the electrostatic recognition device comprises a U-shaped yarn guide, a transparent glass tube and a frequency sensor; the U-shaped yarn guide is installed between the oiling process and the main network process, and an opening of the U-shaped yarn guide faces downwards; a foam ball with the surface coated with tin foil paper is placed in the transparent glass tube, and the two ends of the transparent glass tube are sealed through a metal piece A and a metal piece B respectively; the metal piece A is connected with the U-shaped wire guide through a wire, and the metal piece B is grounded