US Patent 7516509 Pneumatic device for cleaning ventilation ducts

The present application relates to a pneumatic device for cleaning ventilation ducts, which includes a guiding air hammer, a turning conduit, an air-supply pipe and a slewing mechanism for the conduit. The guiding air hammer has a hollow spherical or hemispherical shape and is connected to the turning conduit. A cleaning fumarole and a guiding fumarole are provided on the rear arc wall of the guiding air hammer. When in operation, the air-supply pipe stretching means retracts and stretches the air-supply pipe, which enables the guiding air hammer to clean out the dust on the inner walls and in the corners of a ventilation duct without the need of an operator entering the ventilation duct. The air-supply pipe stretching means may be controlled by manual operation or program composition. The device may be used for cleaning ventilation ducts with a polygonal section.