Heating system for heating plastic material preforms

A heating system for heating plastic material preforms upstream of a blow molding or stretch-blow molding machine, the heating system comprising a heating module adapted to be crossed by a plurality of preforms advancing along a transport line,

• wherein the heating module is provided with a plurality of heating elements arranged along a first plane substantially parallel to a second plane containing axes of the preforms adapted to cross said heating module,
• wherein the heating module comprises
• a first heating zone, proximal to a support area of a neck of the preforms, and comprising at least one first heating element of said plurality of heating elements,
• and at least one second heating zone, arranged adjacent to said first heating zone and at a passage zone of a tubular body of the preforms, and comprising at least one second heating element of said plurality of heating elements,
• wherein the heating system further comprises
• at least one first temperature sensor arranged externally to the heating module and at said first heating zone,
• and at least one second temperature sensor arranged externally to the heating module and at said at least one second heating zone,
• wherein an electronic control device is provided, adapted to receive temperature data detected both by said at least one first temperature sensor and said at least one second temperature sensor compare said temperature data with predefined target temperatures of said first heating zone and said at least one second heating zone and act in feedback by regulating a power of said at least one first heating element and said at least one second heating element;
• and wherein both said at least one first temperature sensor and said at least one second temperature sensor are arranged immediately downstream of the heating module and are facing an outside of said heating module.