Vacuum cleaner
AssigneeA/S Fisker & Nielsen
InventorHans Mathiesen Dall
Life of this patent
Estimating the term…
Abstract
A vacuum cleaner has a casing with an internal duct connecting the air outlet of the vacuum cleaner fan with a discharge aperture. The casing has one or more primary apertures formed in its wall and communicating through the interior of the casing with one or more secondary apertures in the duct wall, whereby the air flow through the duct induces a secondary flow of ambient air through the primary apertures. This secondary air flow effects a cooling of the casing wall and a reduction of the temperature of the discharged air. An apertured internal partition may be provided for locally reducing the cross-section of the coolant air flow path, thereby insuring a uniform cooling effect upon the casing wall.
Claims7
In a vacuum cleaner comprising a motor-driven fan unit mounted in a casing having an unobstructed discharge aperture, internal duct means defining a first air flow passage connecting said discharge aperture with the outlet of said fan unit, and a flow restriction in said first air flow passage intermediate the ends thereof, the improvement comprising the provision of at least one primary air inlet aperture in an outerwall of said casing spaced from said discharge aperture and at least one secondary aperture in a wall of said internal duct means, which primary and secondary apertures communicate by way of a second air flow passage extending through the interior of said casing, said secondary aperture being provided downstream of said flow restriction in an area of said wall, which is obstructed by a hose coupling associated with the vacuum cleaner, when said hose coupling is inserted in said discharge aperture.
Dependencies are inferred from the claim text.