US Patent 8936434 Portable in-line fluid blower

A portable fluid blower with a housing having a central axis and defining a fluid flow path extending axially between an upstream inlet and a downstream outlet. A fan assembly has a rotary component that is operable to draw fluid into a first stage of the flow path and accelerate fluid incoming at the inlet radially outwardly to against a first housing surface portion that diverts the fluid to a second stage of the flow path. The second flow path stage is defined by facing second and third housing surface portions that cause the fluid to flow substantially fully axially in an annular space extending around the central axis between the first stage and a third stage. The fluid flows from the third stage to and through the downstream outlet.