Heating installation and reflecting device for a heating installation

A reflective module made of at least one thermal conductive material to be stacked with other reflective modules according to a stacking axis so as to form a complete reflective device of a heating installation,

• comprising:
• at least one elongated and opened cavity having inner surfaces able to reflect at least a part of IR spectrum and arranged to lodge elongated lamps within, wherein the at least one cavity comprises:
• a curved bottom portion (23a);
• and
• two opposite side surfaces (23b), the curved bottom (23a) joining each of the two opposite side surfaces at a respective longitudinal break of slope,
• wherein, an angle is defined at each break of slope of said cavity and at each break of slope of said cavity the angle of the corresponding side surface with respect to the median plane (P) of the cavity is lower than the angle of the tangent of the curved bottom portion with respect to this median plane.

A process for heating plastic preforms, comprising:

• positioning the preform along a first axis;
• directing radiation from a plurality of elongated lamps onto the preform, each of said plurality of elongated lamps located with a respective elongated and opened cavity defined in a reflective device, with said opened cavities each defining an aperture, and with said opened cavities stacked one onto the other according to a stacking axis, where the aperture of each cavity faces the first axis, and where said stacking axis is parallel to the first axis, and wherein at least one cavity comprises:
• a curved bottom portion, and
• two opposite side surfaces, the curved bottom portion joining each of the two opposite side surfaces at a respective longitudinal break of slope,
• wherein, at each break of slope of said cavity, an angle of the corresponding side surface with respect to a median plane of the cavity is lower than the angle of the tangent of the curved bottom portion with respect to this median plane.