7 COOLING APPARATUS FOR INTERNAL COMBUSTION ENGINES AND THEIR PARTS; BLOWERS OF VENTILATORS, ELECTRICAL, HYDRAULIC, PNEUMATIC VENTILATION DRIVES OR TRANSMISSIONS AND THEIR PARTS; HYDRAULIC LIQUID-COUPLINGS AND THEIR PARTS; COOLING APPARATUS FOR HYDRAULIC AND MECHANICAL TRANSMISSIONS OR POWER GEARS AND FOR MACHINE TOOLS AND THEIR PARTS