GB2454690A

GB2454690A - Cyclonic dust separator for a vacuum cleaner

Info

Publication number: GB2454690A
Application number: GB0722414A
Authority: GB
Inventors: Philip Grove; Mohammed Irfan
Original assignee: Vax Ltd
Current assignee: Vax Ltd
Priority date: 2007-11-15
Filing date: 2007-11-15
Publication date: 2009-05-20
Also published as: WO2009063167A3; GB0722414D0; WO2009063167A2

Abstract

A cyclonic separator for a vacuum cleaner, comprising a first cyclone (10, fig 1) having a body 28, 30 with a central axis, an inlet 34 for tangential entry of dust-containing air to the body 30, an outlet 38 for air from which dust has been separated, extending lengthwise of the axis, and an outlet 44 from the body 28 for separated dust; and a plurality of second cyclones (12, 14, 16, 18, fig 1) each comprising a body 58 with a central axis, an inlet 64 for tangential entry of dust-containing air to the body, an outlet 60 from the body for separated dust, and an outlet 78 for air from which dust has been separated extending lengthwise of the axis, the air outlet 38 from the first cyclone communicating with the inlets 64 to the second cyclones, the second cyclones having their axes extending generally parallel to one another. In one arrangement the first cyclone is disposed with its axis extending generally transversely of the axes of the second cyclones, the air outlet 38 from the first cyclone generally facing the air inlets 64 of at least some of the second cyclones. In a second arrangement the first cyclone comprises a generally cylindrical body with an outlet 44 from the body for separated dust facing transversely outwardly from the body.

Description

Title: Dust Separator for Vacuum Cleaner

Description of Invention

This invention relates to a dust separator for a vacuum cleaner (suction cleaner).

A vacuum cleaner incorporates a dust separator to remove dust and other matter (all herein referred to as dust) from the suction airflow which the cleaner draws from whatever is being cleaned, and retain the separated dust for disposal when required. The dust may include a wide range of sizes of particle, from microscopic up to granules or lumps which may be several millimetres large. There may be other things such as small items of jewellery or (parts of) toys, as well as fibres such as human or animal hair or textile threads. A vacuum cleaner separator should be able to cope satisfactorily with all such types of dust.

The separator with which the invention is concerned is of the so-called cyclonic type, wherein separation of dust from the suction airflow is effected by causing the air to flow rapidly in a circular path in a separating chamber so that particles are separated from the airflow by centrifugal forces and, once they are no longer entrained in the airflow, accumulate in a part of the separating chamber, or in an adjacent collecting chamber, for disposal.

Vacuum cleaners using this separating method have become increasingly popular in recent years, in comparison with cleaners using the traditional method of dust separation which is to cause the suction airflow to pass through a filter which either is interposed in the airflow exit from a chamber in which separated dust is accumulated or takes the form of a filter bag in which the separated dust is collected. As compared with such cleaners, cyclonic cleaners present the advantage that the strength of their suction is not reduced as the filter becomes clogged with accumulated dust. Nevertheless, it remains usual for cyclonic cleaners to incorporate a filter following a cyclonic separator, as a final barrier to the emission of dust particles back into the ambient air and to prevent dust particles being drawn through the motor which creates the suction airflow, it being common to cool the motor by flow of the post-separator air through it after it has left the separator.

Cyclonic separator assemblies incorporating a number of individual cyclonic separators are known. Most simply, a separator assembly may comprise two individual cyclonic separators through which the suction airflow passes successively. The first, upstream separator is of relatively low efficiency and removes large particles of dust from the suction airflow, whilst the second or downstream separator is of greater efficiency (for example, of smaller size and therefore higher circulatory air speed) to remove finer dust particles not removed by the upstream cyclone. More recently, separation has been further improved by providing, instead of a single downstream cyclone, a number of smaller downstream cyclones connected in parallel with one another, so that each can be of high efficiency. As many as 15 to 25 downstream cyclones, connected in parallel with one another, have been proposed for use in cleaners.

There have been many different arrangements of upstream and downstream cyclone in a multi-cyclone separator. For example, it has been proposed that a number of downstream cyclones may be disposed around the periphery or part of the periphery of an upstream cyclone, the axes of all the cyclones being parallel or more or less parallel to one another. A typical arrangement for collection of dust from the cyclones has an inner collecting chamber which forms the bottom part of the upstream cyclone, surrounded or partly surrounded by an annular or part-annular collection chamber, for the downstream cyclones, in which chamber those cyclones are disposed or with which the dust outlets communicate. Another arrangement is to have an upstream cyclone of annular configuration arranged with an interior cavity which forms a dust-collecting chamber for the downstream cyclones, those cyclones being disposed above the level of the upstream cyclone with their dust outlets leading into the interior collecting chamber. Such arrangements of cyclonic separator assemblies, however, have disadvantages in terms of packaging, the former arrangement tending to be of large outside diameter and the latter somewhat tall. Whilst the latter consideration is not highly important for vacuum cleaners of the upright type, it remains the case that if its height is limited to enable the separator assembly to be packaged in a compact, usable and ergonomic vacuum cleaner, the result is that the usable dust1collection capacity is limited for a given overall height of the assembly.

Attempts to incorporate such large numbers of cyclones in a cyclonic separator assembly have introduced problems. Particularly, to provide for the flow of air from an upstream cyclone into the downstream cyclones, divided more or less equally between them, is difficult and has involved complex configurations of passages and large numbers of separate components. It is necessary to provide for flow of air to and exit of cleaned air from each cyclone, and if there are large numbers of cyclones the passages must necessarily be small if the cleaner having the separator is not to be inconveniently large. As well as the difficulty in providing such passages, the necessarily small dimensions thereof lead to the possibility of clogging with dust, giving a further reduction in suction efficiency beyond that which might result simply from the presence of tortuous passages.

A further factor to be considered is that the inlet to a cyclone characteristically extends tangentially of the body of the cyclone, whilst the outlet for cleaner air extends along the axis of the cyclone. In the case where there are multiple downstream cyclones arranged with their axes substantially parallel to one another, and an upstream cyclone whose axis is also substantially parallel to those of the other cyclones, not only are multiple passage portions required to extend to the downstream cyclones but the passage(s) must provide for a more or less right-angled change in the direction of flow of air through the passage. It can be envisaged that this introduces the potential for unduly restricting airflow between the upstream and downstream cyclones.

It is broadly the object of the present invention to address one or more of these problems, and the particular features and advantages of the invention in relation to such problems are particularly described hereafter.

According to one aspect of the invention, we provide a cyclonic separator for a vacuum cleaner, comprising a first cyclone having a body with a central axis, an inlet for tangential entry of dust-containing air to the body, an outlet for air from which dust has been separated, extending lengthwise of the axis, and an outlet from the body for separated dust; and a plurality of second cyclones each comprising a body with a central axis, an inlet for tangential entry of dust-containing air to the body, an outlet from the body for separated dust, and an outlet for air from which dust has been separated, extending lengthwise of the axis, the air outlet from the first cyclone communicating with the inlets to the second cyclones, the second cyclones, having their axes extending generally parallel to one another; wherein the first cyclone is disposed with its axis extending generally transversely of the axes of the second cyclones, the air outlet from the first cyclone generally facing the air inlets of at least some of the second cyclones.

The first cyclone may be arranged, when in a normal orientation assumed in use of a vacuum cleaner in which the separator is used or intended to be used, with its axis extending generally horizontally while the axes of the second cyclones lie generally upright orientation.

A dust-collecting chamber for collecting dust separated by the first cyclone may lie generally beneath the first cyclone. The first cyclone may have a generally cylindrical body, and the outlet for dust separated from the suction air flow by the first cyclone may face transversely outwardly of the body, at or adjacent an end thereof opposite from a first end portion thereof in which the inlet for suction air flow is provided.

The outlet for separated dust from the casing of the first cyclone may comprise a passage extending tangentially from the body, and face a complementary opening in an upper part of the dust-collecting chamber.

Each of the second cyclones may comprise a generally frusto-conical body with an upper portion thereof, having the inlet for air from the first cyclone to enter the second cyclone, generally level with the outlet for air flow from the first cyclone.

Lowermost ends of the frusto-conical bodies of the second cyclones may extend downwardly into a dust-collecting chamber for receiving dust separated by the second cyclones.

It will be apparent from the following description of an embodiment of the invention that a separator in accordance with the first aspect of the invention can give the advantages of compactness and efficiency with, particularly, an extremely straightforward path of flow of air between the first cyclone and the second cyclones, thereby limiting potential losses from airflow restrictions in this area. The configuration of separator is particularly advantageous for vacuum cleaners of the "cylinder" type, although such a separator can be used advantageously in vacuum cleaners of the "upright" type. However, a first cyclone in which the outlet for dust faces laterally, for example tangentially, of that cyclone's body can be useful in providing a compact separator "package" even if it is not arranged to provide the benefit of reduced air flow restriction achieved if the air outlet from the first cyclone faces the air inlet of at least some of the second cyclones.

Therefore, according to a second aspect of the invention, we provide a cyclonic separator for a vacuum cleaner, comprising a first cyclone having a body with a central axis, an inlet for tangential entry of dust containing air to the body, an outlet for air from which dust has been separated, extending lengthwise of the axis and an outlet for separated dust from the body; and a plurality of second cyclones each comprising a body with a central axis, an inlet for tangential entry of dust containing air to the body, an outlet from the body for separated dust, and an outlet of air from which dust has been separated, extending lengthwise of the axis, the air outlet from the first cyclone communicating with the inlets to the second cyclone, the second cyclones having their axis extending generally parallel to one another; wherein the first cyclone comprises a generally cylindrical body and the outlet from the body for separated dust faces transversely outwardly of the body.

Preferably the outlet for separated dust faces generally tangentially of the body. A collecting chamber for dust separated by the first cyclone may have a part which faces the dust outlet from the cyclone, with an opening communicating with the dust outlet.

By use of a first cyclone with such a dust outlet, a compact separator assembly with an upstream first cyclone and multiple downstream second cyclones can be designed.

These and other features of the invention will now be described by way of example with reference to the accompanying drawings, of which: Figure 1 is a diagrammatic perspective view of an embodiment of a cyclonic separator, for a vacuum cleaner, in accordance with the invention.

Figure 2 is a perspective view of the separator as figure 1, but from a different view point.

Figure 3 is a diagrammatic exploded perspective view of the separator.

Referring to the drawings, the embodiment of separator which is illustrated comprises the principal components or sub assemblies of a first, upstream, cyclone indicated generally at 10 and four second, downstream cyclones indicated generally at 12, 14, 16, 18. The separator further comprises a collection bin indicated generally at 20 for dust which is separated from suction airflow by the cyclones, the bin 20 taking the form of a housing 22 with flat side and end walls arranged in rectangular configuration and curved edges, with a transversely extending internal divider wall or partition 23 which separates the interior space of the bin 20 into two parts, one of which lies beneath the first cyclone 10 and the other of which has the second cyclones 12 to 18 extending downwardly into it, so as respectively to be able to receive dust separated from suction airflow by the first and second cyclones. The bin 20 has a base wall assembly indicated generally at 24 for emptying of dust accumulated in the respective parts of the bin 20. The base wall assembly may be, or have a part or parts, pivotably connected to the housing 22 to enable such emptying to be performed, a suitable catch or catches being provided so that the pivotable part(s) can be held in the closed position and opened when required.

The part of the bin 20 lying generally beneath the first cyclone 10 has its upper end closed by a wall 26. a

The first cyclone 10 has a generally cylindrical body which is intended to lie generally in a horizontal orientation when the separator is in use, and comprises two body parts 28, 30, which fit together axially and are secured to one another by, for example and as illustrated, a bayonet connection. The end part 30 has a tangentially-extending inlet duct for dust-laden air drawn by the suction airflow of the vacuum cleaner from whatever is being cleaned. The air inlet duct 32 as illustrated is generally of rectangular cross-sectional shape but could be of any suitable shape or cross-section, and connects to a further inlet duct portion 34 which extends downwardly inside one corner of the part of the bin 20 which forms the collection chamber for dust separated by the first cyclone 10, and extends beneath the lower wall assembly 24 to connect with a suction airflow passage in the vacuum cleaner. The part 30 of the body of the first cyclone further comprises an outlet duct 38 for suction airflow from which some of the dust borne in it, typically larger particles, has been separated by the first cyclone, the outlet duct 38 being provided within the body of the first cyclone with a somewhat frusto-conical perforated "shroud" component 40.

The body part 28 of the first cyclone is predominantly cylindrical, but tapers slightly towards its end opposite the air outlet duct 38 of the cyclone, at which end it is closed by an end wall 42. Adjacent the end wall 42 the body part 28 of the cyclone 10 has a generally tangentially extending outlet passage 44, opposite the inlet duct 32, for dust separated from the air flow by the first cyclone. The outlet passage 44 extends through a corresponding-shaped rectangular opening 46 in the upper wall 26 of the bin 20, so dust separated by the first cyclone can enter the part of the bin 20 beneath the first cyclone.

Each of the second cyclones 12 to 18 comprises a predominantly frusto-conical body of which the bodies of the cyclones 14 to 18 are clearly visible at 54, 56, 58 in figure 3. The uppermost end part of each body is parallel, and such parallel upper part of the body of the cyclone 12 is visible at 52. The lowermost, smallest diameter, ends of the bodies of the second cyclones are open and they have baffle plates supported a short distance below the open ends, as seen at 60 in figure 3 for the cyclone 18 and just visible for the other cyclones. The cyclone bodies 52 to 58 are connected to one another by a joining flange component 62, and are disposed with their central longitudinal axes substantially parallel to one another. The cyclones are arranged with their axes lying generally on an arc of a circle, as the separator is viewed in plan view.

The uppermost parts of the bodies of the cyclones 12 to 18 are formed with tangential air inlet passages, that for the cyclone 16 being visible at 62 in figure 3 and that for the cyclone 18 being visible at 64. Parts of the corresponding inlet passages for the cyclones 12, 14 are visible at 66, 68. In plan view, the passages 62, 64 extend tangentially into their respective cyclones in a clockwise direction so that the circular air flow in the cyclone is in that direction, whilst the inlet passages to the cyclones 12, 14 extend in the opposite direction, i.e. anti clockwise. In an alternative arrangement, all the inlet passages may extend in the same direction as one another.

The inlet passages 62 to 68 of the second cyclones communicate with the air outlet duct 38 of the first cyclone 10. A cover component indicated generally at 70 covers the open tops of the bodies of the cyclones 12 to 18 and with the flange component 62 defines a passage which faces and matches up with the outlet duct 38. Hence the partially dust-separated air leaving the first cyclone enters the second cyclones in which further dust separation takes place.

Since the second cyclones are of smaller diameter than the first cyclone, this dust removal stage is more effective at removing finer dust particles from the suction air flow.

The cover component 70, as well as closing the open tops of the bodies of the cyclones 12 to 18, also defines outlet ducts for clean air leaving the cyclones.

Such ducts are indicated at 72, 74, 76, 78 and each has a short tubular formation which extends downwardly into the respective second cyclone.

Baffles or vanes 80, 82, 84, 86 in such outlet ducts are visible in the drawings; they have the effect of inhibiting circular or turbulent air flow in the outlet ducts of these cyclones, which is beneficial in terms of reducing noise and energy losses.

Although not shown in the drawings, a further cover component would be provided to cover the tops of the cyclones 12 to 18 to receive all the air leaving such cyclones by way of their outlet ducts and to deliver such air to the source of suction (i.e. an electric motor driving an appropriate impeller) of the vacuum cleaner wherein the separator is to be used. Such a further cover may be of any suitable configuration to suit the machine in which the separator is to be used and suitable ductwork would be provided to deliver the air from the cyclones to the source of suction. Usually, a pre-motor filter would be provided to remove any dust particles which might remain in the suction airflow after the successive stages of cyclonic dust separation effected by the separator.

It will be noted from the above description that the air inlet passages 62, 68 for the cyclones 14, 16 are well aligned with the outlet duct 38 of the cyclone 10, so that in flowing from the first cyclone to those Iwo second cyclones there is little energy loss resulting from passages involving significant changes in air flow direction. The passages 64, 66 leading to the cyclones 12, 18 are not quite so well aligned with the duct 38, but nevertheless the air flowing to these cyclones does not have to undergo a change of direction as severe as a right-angle bend in a passage. Therefore, by arranging the first and second cyclones in this way a high degree of airflow efficiency is achieved. The arrangement of the first and second cyclones and the respective dust-collecting chambers therefore is extremely compact and is particularly advantageous in vacuum cleaners of the "cylinder" or "canister" type, although there is still a need for efficient and compact cyclonic separators in vacuum cleaners of the upright" type and a separator assembly in accordance with the invention is also beneficial in meeting this requirement.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof a

Claims

Claims 1. A cyclonic separator for a vacuum cleaner, comprising a first cyclone having a body with a central axis, an inlet for tangential entry of dust-containing air to the body, an outlet for air from which dust has been separated, extending lengthwise of the axis, and an outlet from the body for separated dust, and a plurality of second cyclones each comprising a body with a central axis, an inlet for tangential entry of dust-containing air to the body, an outlet from the body for separated dust, and an outlet for air from which dust has been separated extending lengthwise of the axis, the air outlet from the first cyclone communicating with the inlets to the second cyclones, the second cyclones having their axes extending generally parallel to one another; wherein the first cyclone is disposed with its axis extending generally transversely of the axes of the second cyclones, the air outlet from the first cyclone generally facing the air inlets of at least some of the second cyclones.
2. A separator according to claim I wherein the first cyclone is arranged, when in use of a vacuum cleaner in which the separator is used or intended to be used, with its axis extending generally horizontally.
3. A separator according to claim 2 wherein the axes of the second cyclones lie in a generally upright orientation.
4. A separator according to any one of the preceding claims wherein a dust-collecting chamber for dust separated by the first cyclone lies generally beneath the first cyclone.
5. A separator according to claim 4 wherein the first cyclone has a generally cylindrical body, and the outlet for dust separated from by the first cyclone faces transversely outwardly of the body, at or adjacent an end thereof opposite a first end portion in which the inlet for dust containing air and the air outlet are provided.
6. A separator according to claim 5 wherein the outlet for dust separated by the first cyclone comprises a passage extending tangentially from the body, facing a complementary opening in an upper part of the dust-collecting chamber.
7. A separator according to claim 3 wherein each of the second cyclones comprises a generally frusto-conical body with an upper portion thereof, having the inlet for entry of dust-containing air to the body, generally level with the outlet for flow of air from the first cyclone.
8. A separator according to claim 7 wherein each body of each of the second cyclones has an outlet for separated dust extending axially at the smaller end of the body.
9. A separator according to claim 7 or claim 8 wherein lowermost ends of the bodies of the second cyclones extend into a dust-collecting chamber for receiving dust separated by the second cyclones.
10. A separator according to claim 9 wherein the dust collecting chambers for the first and second cyclones form respective parts of a dust-collecting bin.
11. a cyclonic separator for a vacuum cleaner, comprising a first cyclone having a body with a central axis, an inlet for tangential entry of dust containing air to the body, an outlet for air from which dust has been separated, extending lengthwise of the axis and an outlet for separated dust from the body; and a a plurality of second cyclones each comprising a body with a central axis, an inlet for tangential entry of dust containing air to the body, an outlet from the body for separated dust, and an outlet of air from which dust has been separated, extending lengthwise of the axis, the air outlet from the first cyclone communicating with the inlets to the second cyclone, the second cyclones having their axes extending generally parallel to one another; wherein the first cyclone comprises a generally cylindrical body with an outlet from the body for separated dust facing transversely outwardly from the body.
12. A separator according to claim 11 wherein the outlet from the first cyclone for separated dust comprises a passage extending tangentially from the body.
13. A separator according to claim 11 or 12 wherein a dust-collecting chamber for the first cyclone comprises a part facing the dust outlet from the cyclone, with an opening communicating with the outlet.
14. A separator substantially as hereinbefore described with reference to and/or as shown in the accompanying drawings.
15. Any novel feature or novel combination of features described herein and/or in the accompanying drawings.