US Patent 11173421 Forward secant swirl tube

A forward secant swirl tube may be used to separate heavier particles such as oil and moisture from an air flow. The swirl tube includes a central hub having a centerline and a circular perimeter. An outer circular housing extends from an inlet edge to an outlet edge. A plurality of vanes extends from the central hub to the outer housing. The vanes are equally spaced around the central hub. Each vane has an inlet transition portion connected to a discharge portion. The top edge of the inlet transition portion of each vane is offset from the centerline of the central hub forming a forward secant line with respect to the centerline of the central hub and a direction of spin induced by the plurality of vanes.