Vacuum cleaner having two cyclonic cleaning stages

Abstract

A vacuum cleaner has a first and second cyclonic cleaning stages in series. The second cyclonic cleaning stage has a plurality of second stage cyclones. A conduit connects the first cyclonic cleaning stage outlet and the second stage cyclone inlets.

Description

[0001] This application is a continuation of application Ser. No. 10 / 828,250 filed on Apr. 21, 2004 which is a continuation of U.S. patent application Ser. No. 09 / 679,353 filed on Oct. 5, 2000 which is a division of application Ser. No. 09 / 239,860 filed on Jan. 29, 1999 now issued as U.S. Pat. No. 6,334,234, which is a continuation-in-part of U.S. application Ser. No. 09 / 227,534 filed on Jan. 8, 1999 now issued as U.S. Pat. No. 6,141,826.FIELD OF THE INVENTION [0002] The present invention relates generally to vacuum cleaners having at least two cyclonic separation stages. BACKGROUND OF THE INVENTION [0003] Various types of vacuum cleaners are traditionally produced. These include built in vacuum cleaners, canister vacuum cleaners and upright vacuum cleaners. Upright vacuum cleaners have a ground engaging portion and an upwardly extending portion. The ground engaging portion typically has wheels for movement of the cleaning head across a floor and a suction inlet for the intake of di...

AI Technical Summary

Benefits of technology

[0020] In another embodiment, the upper portion is positionable in a lowered in use position wherein the longitudinally extending axis is at an angle of 40° to the vertical and, when the upper body portion is in the lowered in use position, the centre of gravity of the upper body portion is positioned above the open space. The upper body portion may further comprise a handle, the weight of the handle in the lowered in use position being 2 lbs. or less.

[0021] The spaced apart rear members may have floor contacting members such as glides or wheels adjacent the ends thereof. The floor contacting members may be positioned rearwardly of the centre of gravity when the upper body portion is in the lowered in use position.

[0022] In another embodiment, the upper body portion is pivotally connected to the cleaning head whereby the upper body portion is moveable between an in use positi

Problems solved by technology

If the blockage occurs at a midpoint of the conduit, it may be difficult to clear the blockage.

Further, the addition of a port increases the cost and complexity of the manufacture of the product.

A bend in a conduit for a fluid causes a turbulent pressure loss in the conduit as the fluid travels through the bend in the conduit and the greater the sharpness of the bend, the greater the pressure loss.

One disadvantage of cyclonic vacuum cleaners is the amount of power which is required to create an air flow sufficient to convey the dirty air through the cyclones at sufficient speeds to maintain the air flowing cyclonically through the cyclones

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