Abstract: A cooling ring for a film blowing line, with a ring chamber, which at a peripheral edge forms an outlet gap for the delivery of a cooling medium onto the film bubble (14) and is divided by radial cross members (24) into several segments (34), and with fittings (30, 32) for homogenizing the flow of the cooling medium in the individual segments (34), wherein the fittings have deflector plates (30), which are disposed obliquely to the radial direction and deflect a portion of the cooling medium from the central regions of the segments (34) to the cross members (24).

Abstract: The invention relates to a process for the film correction of the thickness profile of a blown portion in the production of bubble film in which the flow of cooling air is varied in individual peripheral regions of the film bubble. According to the invention, at least part of the cooling air is taken via an exit slot which is divided into individual separately fed segments in the peripheral direction of the film bubble and the supply of additional cooling air via the exit slot is, for example, controlled per segment using radial blowers. In this manner it is possible accurately to regulate the cooling action and thus the film thickness in the individual peripheral regions of the film bubble.