31 POROUS MEDIA AIR FILTERS AND PRESCREENERS FOR GAS TURBINE ENGINES AND INTERNAL COMBUSTION ENGINES; OIL BATH AIR CLEANERS FOR INTERNAL COMBUSTION ENGINES; AIR-OIL SEPARATORS HAVING A COALESCING ELEMENT FOLLOWED BY AN INERTIAL SEPARATOR; AIR INTAKE CAPS AND HOODS FOR AIR FILTERS FOR INTERNAL COMBUSTION ENGINES; VENTILATION PANEL FILTERS FOR VEHICLE OPERATOR CABS, AIR CONDITIONERS, ELECTRONIC EQUIPMENT AND INDUSTRIAL VENTILATION; AIRCRAFT GYRO FILTERS; AND AUTOMATIC SELF-CLEANING DUST FILTERS FOR INDUSTRIAL APPLICATION