7 Filters for the purification of air, gases and fluids as parts of motors, engines and machines, namely, filters for motors and engines, membrane filters for use as parts of machines; filter systems comprising filter housing and replaceable filter elements as parts of machines, motors and engines, namely, filters for motors and engines, membrane filters for use as parts of machines; filter elements for filters and filter systems as parts of motors, engines, and machines all used for mechanical purposes, namely, filter elements for fuel filters, in-line fuel filters, in-tank fuel filter, oil filters, gear oil filters, urea filters, filters for hydraulic fluids, filters for coolants, cooling water filters, washer system filters, spin-on filters, air filters, intake-air filters, aeration filters, ventilation filters, filters for electric discharge machines, liquid filters for machine tools, backflushing filters for liquids, disc filters, filters for compressors, filters for vacuum pumps, vacuum filters, and filters for compressed air systems; air filters for motors and engines; air filter systems for motors and engines comprising air filter housing and replaceable air filter elements; cyclone centrifugal separators for air filters and air filters systems for machines, motors and engines; centrifuges; resonators as parts of motor and engine air intake systems for the attenuation of sound and absorption of vibration; sound absorbers as parts of machines, motors and engines; flaps as parts of motors, engines and machines, namely, orifice flaps, hot air flaps, cold air flaps, and intake manifolds for internal combustion engines; valves as parts of motors, engines and machines; ducts, namely, air intake ducts of motors and engines, clean side ducts of motors and engines, dirty side ducts of motors and engines, exhaust gas recirculation ducts of motors and engines, intake manifolds for internal combustion engines