Inductive weld of joints for optical fiber pipe

The current study presents an induction heating system design for fiber optics pipes joints. Remote heating methods are probably inconvenient due to non-uniform heat distribution resulting in unreliable joints. The induction heating generates uniform heat distribution which can be achieved by proper designing of inductive heating coil, and power system inverter that drives the induction system. Two different shaped open jaw type heating coils were designed i.e open claw type coil (OCTC) and curved spiral rectangular coil (CSRC). The coils were designed in COMSOL simulation software to check the coil and workpiece behaviours. These coil designs were then wounded by hand and resistance and inductance of each coil were measured. The OCTC is a short loop coil, having small inductance while the CSRC has a long loop so its inductance is high. CSRC design was selected in the current application. The CSRC inductance was calculated through modified Wheeler formula and current sheet approximation. To design the power inverter, firstly the power density of heating material i.e workpiece was calculated. Then the thermal losses of the coil were calculated, these losses were due to skin effect and proximity effect; and switch losses due to drain to source resistance(RDS) of Mosfets were estimated. The Mazzilli inverter was proposed for power system inverter design which works as a parallel resonant circuit. It was designed in Mandi simulation software and then implemented on hardware. Theoretical results were compared with the practical measurements through Matlab software. Coil efficiency, power inverter efficiency and overall system efficiency were also calculated. This induction heating method for fiber optics joints is repeatable, consistent, generates uniform heat and is more convenient for site-specific heat generated on workpiece. It is portable, user friendly and environmental friendly as well.