A blow film line and a method for operating the same relates to improving the flow rate in conventional blow film lines without compromising the production quality.The inner cooling body shows an air outlet path, with a cooling ring being embodied in a height-adjustable fashion, with a controller positioning the cooling ring in a lower area of the inner cooling body for the start-up of the facility. The cooling ring is positioned in the upper area of the air outlet path of the inner cooling body in order to achieve the steady-state production.