Method and device for tempering preforms

A method for tempering preforms is a blow-molding machine, comprising the steps of:

• arranging at least one heating box equipped with reflective walls along a transport path for the preforms, said heating box forming a heating channel;
• guiding the preforms through the heating channel in a transport direction, the heating box comprising heating elements for heating the preforms in the heating channel and at least one cooling device comprising a blower for cooling the reflective walls of the heating channel, wherein the cooling of the walls is achieved by a quantity of air flowing along the walls outside the heating channel, wherein heating output of the heating elements of the heating channel is adjustable;
• controlling the cooling of the reflective walls by adjusting cooling output of the cooling device with a control device that provides open-loop or closed-loop control of the cooling output of the cooling device as a function of an associated heating output of the heating elements of the heating channel;
• and monitoring a temperature of the reflective walls and/or of neck areas of the preforms with temperature sensors that are connected to the control device.