Abstract: An engine cooling-system fan formed by combining two fan assemblies of like construction. Each fan assembly comprises a sheet-metal hub with radiating spokes, and a set of fan blades fastened one to each spoke. The hubs of both fan assemblies are riveted or otherwise joined together in axial alignment, with the two sets of fan blades arranged alternately at constant angular spacings. Preferably, the spokes of either or both of the fan assemblies are offset to provide the same plane of rotation for the two sets of the fan blades.

Abstract: An exhaust gas purifier for removing unburned solid particles, sparks, and flames contained in exhaust gas discharged from internal and external combustion engines includes a closed cylindrical member connected to the exhaust port of an internal or external combustion engine and a swirl-generating member disposed in the cylindrical member and provided with a plurality of swirl vanes for swirling the exhaust gas, whereby the length of time that the exhaust gas is disposed in the cylinder is extended and unburned solid particles, sparks, and flames contained in the exhaust gas are centrifugally separated and extinguished thereby discharging relatively clean gas.