The invention relates to fan units for ventilators, in particular for CPAP-apparatus. A non-conformal stressed film that is thicker on the gate structures than between the gate structures is formed over the substrate. If the current waypoint information is positioned on a link after the apparatus passes the node, it means that the apparatus is not deviated from a guidance route corresponding to guidance route information, so that it cuts the connected communication line. The densification treatment is particularly suitable for silicon-oxygen-carbon low dielectric constant films that have been deposited at low temperature. Data is written by applying optical or electric action to the organic compound layer. A filter is positioned in the first conduit for preventing conglomerations of components of the plastic feed stock and fibrous mats formed from components of the plastic feed stock from entering the storage silo and thereby preventing fouling of the plastic plant.