Device to visualize in-line and quantify the polymer melting in plasticating screw machines without significantly affecting its thermal regime

Device to visualize in-line the polymer melting in plasticating screw machines, which comprises an external metallic cylinder fixed in an external radial position relative to a barrel of the plasticating machine, a bushing with an optical window clear to the visible light spectrum resistant to pressure and temperature, positioned in such a way that its external face is tangent to the internal surface of the barrel of the plasticating machine, and an internal metallic cylinder positioned between the external metallic cylinder and the barrel of the plasticating machine to guide the coolant gas and allow the use of an observation probe with operating temperature limits and an illumination system.