Treatment fluid guidance in a film stretching plant

A film stretching plant is described, which comprises a furnace (3), which consists of several treatment zones (1, 1a) which each respectively comprise a ventilation unit (2). The film (4) is suppliable to the furnace (3) through a film inlet region (5) and is thermally treatable zone-wise in the treatment zones (1, 1a). The treatment fluid (6) supplied to the film stretching plant flows over the film (4) on its upper surface and its lower surface in the treatment zones (1, 1a). In the film stretching plant according to the invention, the treatment fluid (6) is circulatable in the respective treatment zone (1, a) by its associated respective ventilation unit (2) for the thermal treatment of the film (4), and a portion (6a) of the treatment fluid (6) is conveyed from the respective treatment zone (1) to the process-technically following treatment zone (1a). This portion (6a) of the treatment fluid (6) that is conveyed into the following treatment zone (1a) is conveyed decoupled from the passage region of the f