Filters are used to clean liquids or gaseous media. They are used to remove individual components or impurities. Typical areas of application are automobiles, household/domestic technology and industry. Air filters, for example, remove aerosols and impurities, oil filters remove dirt particles and residues from the oil circuit of a vehicle. Modern oil filter modules also perform a cooling function. In the field of pneumatics, filters are important components of maintenance units used in mechanical engineering to prepare and provide compressed air. An exemplary maintenance unit consists of a switch-on valve, pressure regulating valve/filter regulating valve, pressure build-up valve, filter, lubricator and dryer. The quality of the compressed air is crucial for a long service life and high availability of pneumatic industrial systems. Domestic water installations are used for water treatment to remove solid particles and prevent damage to the piping system. Service and industrial water installations are also equipped with filters.