| 主权项 |
1. In a portable cyclonic vacuum cleaner that comprises
a cyclonic chamber formed of a conic body having a conic wall, a transverse wall closing off an upper end of said conic wall, and a narrow nose at a lower end of the conic wall, a vortex tube penetrating a center of said transverse wall and descending into said cyclonic chamber, and an inlet conduit penetrating said conic wall below said transverse wall and adapted to introduce into said cyclonic chamber a flow of air in which dust particles are entrained, said air inlet conduit also being adapted to attach to a vacuum conduit; a dust collection drum positioned below said nose, having a drum lid closing off a top of the dust collection drum, the drum lid having a dust inlet opening, with means coupling the nose of the cyclonic chamber to the dust inlet opening of said drum lid, forming a dust seal with said nose to block leakage of external air into the cyclonic chamber and the drum; a filter chamber positioned in the flow of air after said cyclonic chamber, having a housing, an inlet receiving air that exits the vortex tube of the cyclonic chamber, and a cover plate that is removably mounted on said filter chamber housing and having a discharge opening, an air filter cartridge disposed in said housing, the air filter cartridge having an open core and filter media surrounding said open core, and means supporting the filter cartridge on said cover plate with the open core aligned with said discharge opening, such that air discharged from the cyclonic chamber into said filter chamber passes through said media to said open core and exits out said discharge opening; a vacuum blower supported on said cover plate and having a suction port positioned against the discharge opening of said cover plate, to create said air flow into said cyclonic chamber, and then into said filter chamber, through said filter media and out said discharge opening into said vacuum blower suction port; the improvement which comprises an anti-deflagration screen mounted upon the discharge opening of the cover plate of the filter chamber, and through which filtered air passes in its path from the open core of the filter cartridge into the suction port of the vacuum blower; the anti-deflagration screen being in the form of a metal mesh creating a multiplicity of small passages to permit exhaust air flow from the filter chamber but blocking any flame front. |
