Design and Experimental Study of Full-Process Automatic Anti-Corrosion Joint-Coating Equipment

Pipeline joint coating is key to maintaining the integrity and service life of oil and gas pipelines. This study presents a novel full-process automatic joint-coating system, comprising a modular design of a universal chassis and four operational modules: abrasive blasting, medium-frequency heating, primer spraying, and heat-shrink-tape wrapping. The innovation lies in its axial obstacle-crossing mechanism, automated opening/closing device, and circumferential rotation system, enabling semi-automated joint-coating operations with the potential for full automation in future iterations. Finite element simulations confirmed the structural strength and safety margins of critical components under operational loads. Experimental validation demonstrated that pre-heating to 120 °C via 5 kHz heating took only 2 min (versus 3 min at 4 kHz and over 5 min at 3 kHz) and that primer-spraying parameters (nozzle height/travel speed) produced uniform coating thickness above 400 µm. Adhesion tests at pipe temperatures above 200 °C and rolling speeds ≤ 16 mm/s consistently exceeded 100 N/cm, while speeds above 20 mm/s caused defects. The system therefore offers a reliable engineering solution for high-efficiency, reproducible pipeline joint-coating operations.