GB2427841A

GB2427841A - Cyclone separator

Info

Publication number: GB2427841A
Application number: GB0513602A
Authority: GB
Inventors: Stuart Robert Bruce; Ross Richardson
Original assignee: Hoover Ltd
Current assignee: Hoover Ltd
Priority date: 2005-07-02
Filing date: 2005-07-04
Publication date: 2007-01-10
Anticipated expiration: 2025-07-04
Also published as: GB2427841B; GB0513602D0; GB0513630D0

Abstract

A cyclone separator unit comprising a cyclone assembly mounted to a dirt collection receptacle 24. The cyclone separator unit comprises a cyclone chamber 28 and a cyclone outlet tube 32 formed with a number of windows in which a mesh is fitted to provide perforations 31. In use dirt-laden air enters the cyclone chamber 28 via inlet port 30, and is constrained to follow a swirling path so solid particles migrate towards the circumferential wall of the cyclone chamber 28. The air from which the solid particles have been separated is drawn through the perforations in outlet tube 32 and flows upwardly through the outlet tube 32. The solid particles pass into receptacle 24 through opening 37. A secondary airflow is set up between the outlet 37, the interior of the receptacle 24 and the outlet tube 32 without returning to the chamber 28. The secondary airflow assists in transferring the separated dirt and dust into receptacle 24. The cyclone assembly is pivotally mounted to the receptacle 24 to allow the receptacle to be emptied. Other optional elements include filter unit 26, chamber lower wall 34, mesh screen 36 and radially enlarge portion of chamber 29.

Description

Cyclone Separator The present invention relates to a cyclone separator,

particularly but not solely for a vacuum cleaner.

Vacuum cleaners are of two principal types, namely the canister or cylinder cleaner, or the upright cleaner. In both types of vacuum cleaner, an electrically-driven motor/fan unit draws air through a chamber in which a separator is disposed, this separator conventionally comprising a filter bag of permeable material, the interior of which is in fluid communication with a conduit conveying air from a floor-engaging nozzle or other suction inlet of the cleaner. Dirt-laden air from the suction inlet is drawn into the filter bag, and the air is then drawn out through the walls of the filter bag and into the separator chamber, leaving the dirt and dust within the filter bag. The clean air is drawn out of the separator chamber by the fan of the motor/fan unit and expelled from the vacuum cleaner through an exhaust port to ambient. It is conventional to provide a pre-motor filter between the separator chamber and the inlet to the fan, and an exhaust filter downstream of the fan.

It is an inherent disadvantage of the filter bag separators of vacuum cleaners that, should the user neglect to replace the filter bag in accordance with the manufacturer's * recommendations, then an excessive quantity of dirt will accumulate in the filter bag and this will give rise to a reduction in the air through- flow rate, with a consequent reduction in the *:::: cleaning power and effectiveness of the vacuum cleaner.

As an alternative to filter bags, it has become common to use cyclone separators in vacuum cleaners. Whilst with filter bags the dirt and dust is fully enclosed within the bag during bag replacement, cyclone separators suffer the disadvantage of requiring an emptying l* .: process which involves tipping a mass of dirt and dust out of a collection receptacle of the separator, typically into a dustbin. This is a dirty and unhygienic process. In addition, many cyclone separators have hitherto exhibited a tendency for becoming blocked, particularly by fibrous material or by dirt or dust of relatively large particle-size, and have not achieved the level of separation performance obtainable with filter bags: smaller cyclone separators, of a size suitable for use in vacuum cleaners of the canister type, are particularly susceptible to blocking. For this reason, the effective use of cyclone separators has, with few exceptions, been confined to cleaners of the upright type, because these are able to accommodate cyclone separators of relatively large size. In many vacuum cleaners employing cyclone separators, a second stage of separation is provided downstream of the cyclone; conventionally this comprises a large filterwhichrequiresroutine maintenance, generallyeitherperiodic washing or replacement.

In recognition of the relative advantages and disadvantages of the different types of separator described above, vacuum cleaners have been placed on the market, in recent times, which are able to accept either a filter bag or a cyclone separator, at the choice of the user. A typical example of such cleaners is disclosed in International patent application WOO 1/82767, in the form of a canister cleaner provided with a removable cyclone separator unit or cassette. In order to provide separation and filtration perfonnance comparable with that of a filter bag, the cyclone separator unit comprises a cyclone separator, a dust-collection chamber or receptacle, and a large filter, it is clear that, for this cassette to be accommodated within the space alternatively occupied by a filter bag of perhaps three litres capacity, a unit of extremely compact construction is essential, which clearly places limitations on the size of the cyclone separator itself. It has been found that, in practice, and owing to the small dimensions of the cyclone separator, cyclone separator cassettes of this type are prone to becoming blocked by fibrous material andlor dirt of the larger particle size, with consequent loss in performance and the need for frequent clearing. S...

* . *. We have now devised a cyclone separation unit in which the risk of blockage is *a..

substantially reduced or eliminated, even where the unit is relatively small or compact in size. S...

*. In accordance with the present invention, there is provided a cyclone separation * * 20 unit which comprises a cyclone separation chamber having an inlet for the inflow of air or gas in which particulate material is entrained, a first outlet for air or gas from which said particulate material has been separated by cyclonic action within said chamber, and a second * *: outlet for the separated particulate material, the unit further comprising a collecting receptacle in fluid communication with said second outlet and serving to collect the separated particulate material, and said collecting receptacle being in fluid communication with said first outlet of said cyclone separation chamber such that, in use, there is a secondary flow of air or gas out of said cyclone separation chamber, into said collecting receptacle and through said first outlet.

The secondary flow of air or gas passes out of the cyclone chamber, into the collecting receptacle and then to said first outlet, preferably without returning to the cyclone separation chamber.

Preferably the unit is arranged so that said secondary flow of air or gas forms a relatively small proportion of the total flow of air or gas through the unit.

Preferably the unit comprises an outlet tube extending through the cyclone separation chamber and formed with one or more openings or perforations for the flow of air or gas from said chamber and into said tube, and then along said tube and out through one end thereof, the opposite end of said tube being in fluid communication with the collecting receptacle, for receiving said secondary flow from said receptacle.

Preferably the unit further comprises filtering means through which said secondary flow is constrained to pass. Preferably this filtering means is disposed at or adjacent the upstream end of said outlet tube of the unit.

Conveniently, the unit comprises a cyclone assembly, which includes the cyclone separation chamber, pivotally mounted to the collecting receptacle and arranged to close an opening in the receptacle, typically at the top thereof, but pivotally movable to open said opening to allow the receptacle to be emptied of its contents.

Also in accordance with the present invention, there is provided a cyclone separation unit which comprises a cyclone assembly pivotally mounted to a collecting receptacle and arranged to close an opening in said receptacle but pivotally movable to open I...

* *.* said opening to allow said receptacle to be emptied, said cyclone assembly including a cyclone separation chamber having an inlet for the inflow of air or gas in which particulate material **.

*. : is entrained, a first outlet for air or gas from which said particulate material has been * 20 separated by cyclonic action within said chamber, and a second outlet for the separated * particulate material, said second outlet being in fluid communication with said receptacle.

* * An embodiment of the present invention will now be described by way of example only and with reference to the accompanying drawings, in which: FIGURE 1 is a view of a vacuum cleaner of the upright type in which a cyclone separator unit or cassette in accordance with the present invention may be used; FIGURE 2 is an enlarged view of a front portion of the vacuum cleaner of Figure 1, showing an access cover to the separator chamber being opened; FIGURE 3 is a similar view, showing a cyclone separator unit or cassette being fitted into the separator chamber; FIGURE 4 is a top plan view of the cyclone separator unit or cassette, shown with its filter unit removed; FIGURE 5 is a longitudinal section through the cyclone separator unit or cassette, taken on the line V-V in Figure 4; FIGURE 6 is a longitudinal section through the cyclone separator unit or cassette, taken on the line Vi-VI in Figure 4; and FIGURE 7 is a diagrammatic longitudinal section through the cyclone separator unit or cassette, for use in explaining the manner in which the unit works.

Referring to Figure 1 of the drawings, there is shown an upright vacuum cleaner which comprises a wheel-mounted, floor-engaging unit 10 to which an upright body 12 is mounted. The upright body 12 is formed with a chamber 11 (Figures 2 and 3) which is open to the front of the body 12 and provided with a transparent cover 13. An electrically powered motor/fan unit (not shown) is mounted in a compartment of the body 12, below the chamber 11, and serves to apply suction to the chamber 11. The chamber 11 has an inlet port 14 (Figure 3) for dirt-laden air drawn into the cleaner either through a suction inlet in the underside of the floor-engaging unit 10 or through a suction nozzle 15 and associated flexible duct 16. For the separation and retention of dirt and dust from the incoming air flow, a filter bag or a rigid porous dust box or (as shown in the drawings) a cyclone separator unit may be fitted into the chamber 11 and coupled to the inlet port 14. Figure 2 shows the cover 13 of a...

* ..* the chamber 11 being opened and Figure 3 shows a cyclone separator unit or cassette 20 being S...

fitted into the chamber 11. S...

*. : Referring to Figures 4 to 6 of the drawings, the cyclone separator unit 20 comprises a cyclone assembly 22 mounted at the top of an elongate dirt-collection receptacle a. 24, and a filter unit 26 mounted to the top of the cyclone assembly 22. The receptacle 24 is :: generally of the shape of a trapezium in cross-section and the cyclone assembly 22 comprises a tubular outer casing 23 which is pivotally coupled to the top of the receptacle 24 by means of a hinge 25 extending across the narrower or rear side of the separator unit: a catch 27 is provided on the opposite or wider side of the separator unit 20, for retaining the cyclone assembly 22 in its closed position across the top of the receptacle 24, but also being releasable for hinging the cyclone assembly 22 upwards, together with the filter unit 26, to open the receptacle 24 for emptying the latter of dust and dirt collected in it.

The cyclone assembly 22 comprises a cylindrical chamber 28 which is formed with a tangential air inlet communicating with an inlet port 30 provided on the narrower or rear side of the separator unit, above the hinge 25, the inlet port 30 being arranged to couple to the air inlet port 14 of the separator chamber 11 of the cleaner when the cyclone separator unit 20 is fitted into the latter chamber. A cyclone outlet tube 32 extends axially of the cylindrical chamber 28 and an annular wall 33, in the form of a spiral-shaped ramp, closes the space between the top of the chamber 28 and the outlet tube 32. The cyclone outlet tube 32 is formed with a number of windows e.g. 32a in which a mesh (not shown) is fitted to provide a multiplicity of perforations 31 (Figure 7) distributed over its surface. An annular wall 34 closes the space between the lower end of the separator chamber 28 and the lower end of the cyclone outlet tube 32. A mesh screen 36 is mounted across the lower end of the cyclone outlet tube 32. The cylindrical cyclone chamber 28 is radially enlarged, at a location 29 on one side of the chamber 28 and adjacent its lower end, and the lower wall of the chamber 28 is formed at this point with an opening 37 to provide a downwardly-directed passage from the chamber 28 and into the dirt-collection receptacle 24. It will be noted, particularly from Figure 4 of the drawings, that this radially- enlarged portion 29 of the chamber 28 is directed generally into one of the corners of the cyclone separator unit, adjacent its wider side.

It will be appreciated that, in operation of the vacuum cleaner which has been described, the motor/fan unit applies suction to the chamber 11 in which the separator unit 22 is fitted, so that the separator unit or cassette is subjected to a negative pressure over its a...

*1 entire external surface, including the external surface of the filter unit 26. Accordingly, dirt- laden air is drawn into the cleaner, either through the suction inlet in the underside of the ::: : floor-engaging unit 10 or through the suction nozzle 15, into the separator unit 20 via its inlet, then through the cyclone separator 22 and out through its outlet tube 32 and through the filter unit 26. The dirt-laden air which enters the cyclone chamber 28, through its inlet, does so * tangentially of the chamber 28 and is constrained to follow a swirling path, creating a vortex in which solid particles migrate towards the circumferential wall of the cyclone chamber: the air, from which the solid particles have been separated, is drawn radially inwardly towards the cyclone outlet tube 32 and through its perforations and into the outlet tube itself; thereafter, this air flows upwardly through the outlet tube 32, then through the filter unit and into the chamber 11 in the body 12 of the cleaner, after which the air passes through the motor/fan unit and is finally expelled from the cleaner via an exhaust outlet (not shown). A final filtration stage is preferably provided downstream of the motor/fan unit and upstream of the exhaust outlet.

The swirling airflow within the cyclone chamber 28 of the separation unit or cassette causes the separated particles to move over the inner wall of the chamber 28, circumferentially thereof, towards and out through the opening 37 in the lower wall 34 of the cyclone chamber28, the particles of dirt passing into the dirt-collection receptacle 24, where they are retained. It will be noted that the interior of the dirt-collection receptacle 24 is in communication with the lower end of the cyclone outlet tube 32, via the mesh screen 36. A secondary airflow is accordingly set up between the tangential inlet of the cyclone chamber 28 and the outlet of the cyclone separator, by way of the separated- material outlet 37 of the cyclone chamber 28, the interior of the dust receptacle 24, the mesh screen 36 and the cyclone outlet tube 32, and without returning to the cyclone chamber 28. The overall area and mesh size of the screen 36 are so chosen that this secondary airflow forms only a relatively small proportion of the total airflow through the cyclone separator unit or cassette 20.

The above-described secondary airflow, passing through the dust receptacle 24, assists in transferring the separated dirt and dust from the cyclone chamber 28 and to the dirt collection receptacle 24. As a result, the purging of separated dirt from the cyclone is greatly improved and the risk of the cyclone becoming blocked owing to the accumulation of coarse andlor fibrous material, even where the cyclone is relatively small or compact, is substantially reduced or eliminated. q *Se.

* *** Whilst a cyclone separation unit or cassette in accordance with the present invention has been described for use in a vacuum cleaner of the upright type, it will be CI..

appreciated that the unit may instead be arranged for use in vacuum cleaners of the canister type. 0 * $ o. 0$ I s

Claims

1. A cyclone separation unit which comprises a cyclone separation chamber having an inlet for the inflow of air or gas in which particulate material is entrained, a first outlet for air or gas from which said particulate material has been separated by cyclonic action within said chamber, and a second outlet for the separated particulate material, the cyclone separation unit further comprising a collecting receptacle in fluid communication with said second outlet and serving to collect the separated particulate material, and said collecting receptacle being in fluid communication with said first outlet of said cyclone separation chamber such that, in use, there is a secondary flow of air or gas out of said cyclone separation chamber, into said collecting receptacle and through said first outlet.

2. A cyclone separation unit according to claim 1, wherein the secondary flow of air or gas passes out of the cyclone chamber, into the collecting receptacle and then to said first outlet without returning to the cyclone separation chamber. *S

::::

3. A cyclone separation unit according to claim I or claim 2, wherein the cyclone separation unit is arranged so that said secondary flow of air or gas forms a relatively small * : :* proportion of the total flow of air or gas through the cyclone separation unit.

4. A cyclone separation unit according to any preceding claim, wherein the S... . . . * S cyclone separation unit compnses an outlet tube extending through the cyclone separation chamber and formed with one or more openings or perforations for the flow of air or gas from said chamber and into said tube, and then along said tube and out through one end thereof and wherein the opposite end of said tube is in fluid communication with the collecting receptacle, for receiving said secondary flow from said receptacle.

5. A cyclone separation unit according to any preceding claim, wherein the cyclone separation unit further comprises filtering means through which said secondary flow is constrained to pass.

6. A cyclone separation unit according to claim 5, wherein the filtering means is disposed at or adjacent the upstream end of said outlet tube of the cyclone separation unit.

7. A cyclone separation unit according to any preceding claim comprising a cyclone assembly, including the cyclone separation chamber, pivotally mounted to the collecting receptacle and arranged to close an opening in the collecting receptacle and pivotally movable to open said opening to allow the receptacle to be emptied of its contents.

8. A cyclone separation unit which comprises a cyclone assembly pivotally mounted to a collecting receptacle and arranged to close an opening in said receptacle but pivotally movable to open said opening to allow said receptacle to be emptied, said cyclone assembly including a cyclone separation chamber having an inlet for the inflow of air or gas in which particulate material is entrained, a first outlet for air or gas from which said particulate material has been separated by cyclonic action within said chamber, and a * . second outlet for the separated particulate material, said second outlet being in fluid :: :a: 15 communication with said receptacle. * * * a S *S lb

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