SG180032A1 - System and method for separating dirt from an air flow - Google Patents

Abstract

A system and method for separating dirt from an air flow. The systemcomprises a first centrifugal separation chamber for receiving the air flow to separateat least some dirt particles from the air flow; a second centrifugal separationchamber disposed downstream from the first centrifugal separation chamber forfurther separating at least some of remaining dirt particles from the air flow; and ashroud disposed between the first and second centrifugal separation chambers forpreventing dirt particles having dimensions larger than a pore size of the shroudfrom leaving the first centrifugal separation chamber, wherein the shroud isdisposed, in an operating orientation, above an inlet for the air flow of the firstcentrifugal separation chamber.FIG. 1

Description

SYSTEM AND METHOD FOR SEPARATING DIRT FROM AN AIR

FLOW

FIELD OF INVENTION

The present invention relates broadly {0 a system and method for separating dirt from an air flow, and to a method of fabricating a system for separating dirt from an air flow.

BACKGROUND

Bagless vacuum cleaners such as those marketed under the brand “Dyson” have become increasingly popular. One advantage that such bagless vacuum cleaners have over traditional vacuum cleaners using dirt bags is their relatively constant suction power, whereas traditional vacuum clesaners tend to lose suction power over time due to the accumulation of dirt in the bags. Another major appeal of bagless vacuum cleaners is that the removal of the dirt from a filled bag or replacement of a disposable bag, which may be quite messy, is no longer necessary. in addition, the operating cost of a bagless vacuum cleaner is also lower as no bags need to be purchased.

In a typical bagless vacuum cleaner, dirty air is subjected to cyclonic movement, in e.g. a substantially cylindrical chamber, such that dirt is separated from air as a result of a centrifugal separation process. The dirt then collects at the bottom of the chamber while the clean air is exhausted through an outlet. However, early bagless vacuum cleaners employing single-stage separation are not very effective in separating fine dust particles, which are relatively light, from air.

Subsequent improvements have resulted in systems in which a filter device is disposed adjacent to the chamber outlet for trapping the fine dust particies.

However, the filter device needs to be routinely inspected and, if necessary, cleaned or replaced to ensure consistent performance. Such maintenance work can be troublesome and messy because the filter device may be shaped or positioned in an awkward manner, in a different approach to improve the performance of bagless vacuum cleaners, EF Patent No. 0 042 723 discloses a system using a two-stage separation apparatus, i.e. a low efficiency cyclone unit for dealing with dirt particles of relatively larger size and a high efficiency cyclone unit for dealing with fine particles. However, in that system, a pipe is used, without any mesh or filter, to channel air from the iow efficiency cyclone unit to the high sfficiency cycione unit. Thus, some larger but light particles, e.g. fibers, may move into the pipe and potentially block the airfiow, or into the high efficiency cyclone unit where they may cause noise.

A further improved vacuum cleaner using a two-stage separation apparatus is disclosed in WIPG Publication No. WO 02/067750 where a shroud in the form of an apertured annular wall is disposed at the outlet of the first separation stage.

However, as the shroud causes air to perform a sharp change of direction, the apertures are not evenly utilized. For example, air is more likely to pass through the apertures nearest to the first separation chamber than those further away. Also, as the shroud is placed below the dirty air inlet, some of the large dirt particles may become stuck at the apertures during their downward spiral motion. As a result, the efficiency of the system may be lowered,

Yet another vacuum cleaner using two dirt separation and collection zones is disclosed in US Patent No. 7,419,522. in said prior art system, a conical shroud is disposed between the first separation zone (for coarse dirt) and the second separation zone (for fine dirt). However, similar to the above WIPO pubiication, as the conical shroud is placed below the dirty air inlet, some of the large dirt particles may become stuck at the apertures during their downward spiral motion. In addition, the system may be noisy due to the relatively fast movement of air in the narrow space between the conical shroud and the conical second separation zone.

Furthermore, vanes are required at the opening of the second separation zone to create a cyclonic effect. The use of a conical shroud and vanes also makes the manufacturing and maintenance of the system relatively difficult.

A need therefore exists to provide a system and method for separating dirt from air that seek to address at ieast one of the above problems, or to at least provide an alternative.

SUMMARY in accordance with a first aspect of the present invention, there is provided a system for separating dirt from an air flow, the system comprising: a first centrifugal separation chamber for receiving the air flow to separate at least some dirt particles from the air fiow; a second centrifugal separation chamber disposed downstream from the first centrifugal separation chamber for further separating at least some of remaining dirt particles from the air flow; and a shroud disposed between the first and second centrifugal separation chambers for preventing dirt particles having dimensions larger than a pore size of the shroud from leaving the first centrifugal separation chamber, wherein the shroud is disposed, in an operating orientation, above an inlet for the air flow of the first centrifugal separation chamber.

The inlet of the first centrifugal separation chamber may be disposed substantially tangential to a side wall of the first centrifugal separation chamber.

An inlet of the second centrifugal separation chamber may be disposed substantially tangential to a side wall of the second centrifugal separation chamber.

The inlets may be tangential in a clockwise manner.

The shroud may be disposed substantially horizontally, in the operating orientation.

The first centrifugal separation chamber may be made of a transparent maierial.

The first centrifugal separation chamber may be substantially cylindrical.

The second centrifugal separation chamber may comprise an inverted cone.

The first centrifugal separation chamber and the second centrifugal separation chamber may be substantially co-axial.

The second centrifugal separation chamber may be disposed substantially within the first centrifugal separation chamber.

The shroud may comprise an annular disk separating the outlet of the first centrifugal separation chamber and the inlet of the second cenirifugal separation chamber,

The shroud may comprise a nylon mesh.

The system may further comprise a filter disposed at an outlet of the second centrifugal separation chamber,

In accordance with a second aspect of the present invention, there is provided a vacuum cleaner comprising the system as defined in the first aspect.

The vacuum cieaner may further comprise a motor compartment disposed horizontally adjacent to said system. tn accordance with a third aspect of the present invention, there is provided a method for separating dirt from an air flow, the method comprising the steps of: separating at least some dirt particles from the air flow in a first centrifugal separation chamber that receives the air flow: further separating at least some of remaining dirt particles from the air flow in a second centrifugal separation chamber disposed downstream from the first centrifugal separation chamber; and disposing a shroud between the first and second centrifugal separation chambers for preventing dirt particies having dimensions larger than a pore size of the shroud from leaving the first centrifugal separation chamber, wherein the shroud is disposed, in an operating orientation, above an inlet for 5 the air flow of the first centrifugal separation chamber. tn accordance with a fourth aspect of the present invention, there is provided a method for fabricating a system for separating dirt from an air flow, the method comprising: providing a first centrifugal separation chamber for receiving the air flow to separate at least some dirt particles from the air flow; providing a second centrifugal separation chamber downstream from the first centrifugal separation chamber for further separating at least some of remaining dirt particies from the air flow; providing a shroud between the first and second centrifugal separation chambers for preventing dirt particles having dimensions larger than a pore size of the shroud from leaving the first centrifugal separation chamber; and disposing the shroud, in an operating orientation, above an inlet for the air flow of the first centrifugal separation chamber,

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will be better understood and readily apparent to one of ordinary skill in the art from the following written description, by way of example only, and in conjunction with the drawings, in which;

Figure 1 shows a schematic diagram illustrating a system for separating dirt from air according to an example embodiment.

Figure 2A shows a perspective view of an example implementation of the sysfem of Figure 1.

Figure 2B shows a cross-sectional view of an example implementation of the system of Figure 1.

Figure 2C shows an exploded perspective view of an example implementation of the system of Figure 1.

Figure 3 shows a perspective view of a first separation chamber according to an example embodiment.

Figure 4 shows a perspeciive view of a second separation chamber according {0 an exampie embodiment. ~ Figure § shows a perspective view of a fine dust collector according to an example embodiment,

Figure 6 shows a perspective view of a shroud according to an example embodiment.

Figure 7 shows a perspective view of a top cover according to an example embodiment.

Figure BA shows an image of a prototype of the system for separating dirt from air according to an example embodiment.

Figure 8B shows an alternate view of the prototype of Figure 8A.

Figure © shows an image of an optional filter according to an example embodiment.

Figure 10 shows an image of the prototype of Figure 8A with the optional filter of Figure 9.

Figure 11A shows an image of a front side of a motor assembly according to an example embodiment.

+

Figure 11B shows an image of a back side of the motor assembly of Figure

T1A.

Figure 11C shows a close-up image of a cord winding sub-assembly of the motor assembly of Figure 11A.

Figure 11D shows a close-up image of power button sub-assembly of the motor assembly of Figure T1A.

Figure 12 shows an image of a vacuum cleaner during assembly according to an example embodimant.

Figure 13 shows an image of the vacuum cleaner of Figure 12 with a top housing according te an example embodiment.

Figure 14 shows a flow chart illustrating a method for separating dirt from an air flow according fo an example embodiment.

Figure 15 shows a flow chart illustrating a method of fabricating a system for separating dirt from an air flow according to an example embodiment.

DETAILED DESCRIPTION

Figure 1 shows a schematic diagram illustrating a system 100 for separating dirt from air according to an example embodiment. System 100 comprises a first separation chamber 102 configured for separating substantially large dirt particles from air, a second separation chamber 112 disposed substantially within the first separation chamber 102 and configured for separating substantially fine dirt particles (e.g. dust) from air, and a shroud 108 disposed between the first separation chamber 102 and the second separation chamber 112.

In the example embodiment, the first separation chamber 102 comprises an air inlet 104 disposed tangential to an upper end of a side wall 105. Typically, a suction mechanism (not shown) coupled to the system 100 excites and sucks dirt, from e.g. a floor or carpet, into the first separation chamber 102 via a hose or pipe (not shown} connected to the air intet 104. Thus, the size of dirt is typically limited by e.g. the pipe opening and/or diameter. Dirty air enters the first separation chamber 102 at a substantially tangential direction and high speed, and undergoes a spiral rotational (i.e. cyclonic) motion within the first separation chamber 102.

Due to the different centrifugal forces experienced by air and dirt respectively, dirt particles are separated from air and collect at an area 106 at the bottom of the first separation chamber 102. it will be appreciated that, to maximize the effects of gravity and centrifugal separation, the axis of the first separation chamber 102 is preferably substantially vertical during operation. Partially clean air then moves up the first separation chamber 102 and passes through the shroud 108 disposed at the outst,

As can be seen from Figure 1, the shroud 108 is in the form of a porous annular disk disposed substantially horizontal in the example embodiment (i.e. substantially perpendicular to the axial direction of the first separation chamber 102).

This arrangement advantageously provides a more simple construction and assembly, as well as enables a more even use of the shroud 108 compared to prior art approaches. Also, dirt particles that become temporarily stuck at the shroud 108 during use may fall off under the effect of gravity after the system is switched off. In addition, as the shroud 108 is positioned higher in the first separation chamber 102 with respect io the air inlet 104 during operation in the example embodiment, the shroud 108 is advantageousiy less likely to be choked by large dirt particles, which tend to spiral downwards to be deposited at area 106. Preferably, the shroud 108 allows substantially fine dirt particles to enter the second separation chamber 112.

Similar to the first separation chamber 102, the second separation chamber 112 comprises an air inlet 114 that is substantially tangential to its side wall for initiating a spiral rotational air motion within the chamber 112. In addition, the air intet 114 is disposed adjacent fo the shroud 108 such that the filtered air travels a g substantially short spiral within a space 109 defined by a top cover 110. the shroud 108 and the top end of the second separation chamber 112 before entering the second separation chamber 112.

In the example embodiment, the second separation chamber 112 comprises an inverted cone (i.e. smaller bottom end}. As the radius of the cone decreases, the speed of the air-dirt mixture increases significantly, thereby enabling the separation of very fine dirt particles from air towards the bottom end as a result of centrifugal separation. The fine dirt particles fall into a dust collector 116 disposed directly below the bottom end of the cone while substantially clean air moves upwards through an outlet 118 to be further treated or exhausted. As will be appreciated by a person skilled in the art, air-tight seals 120, 122 are typically provided at the boundaries between the dust collector 116 and the first separation chamber 102, and between the dust collector 116 and the second separation chamber 112 1S respectively.

Figure 2A shows a perspective view of an example implementation of the system of Figure 1. Figure 2B shows a cross-sectional view of an example implementation of the system of Figure 1. Figure 2C shows an exploded perspective view of an example implementation of the system of Figure 1. As can be seen from

Figure 2A, the first separation chamber 102 is substantially cylindrical in the example embodiment. Also, the air inlet 104 is tangential fo a side wall of the first separation chamber 102. Figure 2A further shows a support structure 124 of a filter (described in detail below) and an adaptor structure 126 for coupling the air inlet 104 to a conventional air hose/pipe.

In addition, as can be seen in Figure 2B, the first separation chamber 102, the dust collector 116, the second separation chamber 112, the shroud 108 and the top cover 110 are substantially co-axial. Furthermore, the shroud 108 is positioned higher than the air inlet 104 in the axial direction in the example embodiment. The inlet 114 of the second separation chamber 112 is disposed in space 109 defined by the top cover 110, the shroud 108 and the top end of the second separation chamber 112. The arrangement according the example embodiment advantageously keeps the system compact. in addition, system efficiency may be enhanced because, after passing through the shroud 108, the air flow can reach the second separation chamber 112 quite fast after undergoing a relatively short spiral movement within space 108.

With reference to Figure 2C, the assembly of the system 100 is now described. In a preferred embodiment, the conical body of the second separation chamber 112 is inserted through an inner ring of the shroud 108 unti} the shroud is secured from axial movement relative to the second separation chamber 112 (to be described in detail below). The bottom end of the second separation chamber 112 securely rests within an opening provided on a top face of the dust coliector 116, e.g. by using give at seal 122. The dust coilector 118, which comprises a hollow bottom face in the example embodiment, is then removably mounted to the bottom surface of the first separation chamber 102, e.g. by engaging with seal 120. The top cover 108 is then mounted over both the first separation chamber 102 and the second separation chamber 112 in 2 manner that prevents rotational or axial movement of the chambers 102, 112 relative to the top cover 110 (to be described in detail below). in addition, the filter together the support structure 124 is mounted on top of the cover 110, and the adaptor structure 126 is mounted to the first separation chamber.

To dissembie the system 100, e.g. during maintenance or removal of dirt, the top cover 110 is first dismounted. In the example embodiment the second separation chamber 112 together with the dust collector 118 can be disengaged from seal 120. Shroud 108 can be easily cleaned {o remove entrenched dirt, or even replaced. Debris collected from both separation stages can be emptied e.g. by pouring into a suitable rubbish bin.

Figure 3 shows a perspective view of a first separation chamber 102 according to an example embodiment. The first separation chamber 102 is preferably made of a material that can withstand the effects associated with the cyclonic movement of the air-dirt mixture, e.g. pressure difference, impact of fast- moving dirt particles on walls, without collapsing or shattering. Preferable materials for the first separation chamber 102 inciude, but are not limited fo, acrylic and polycarbonate, which are also substantially transparent, thereby ailowing a quick inspection of the contents and parts therewithin.

For example, in an embodiment where the diameter of the first separation chamber 102 is about 160 millimeters (mm) and the height of the first separation chamber 102 is about 150 mim, the center of the air inlet 104 is about 40 mm below the top end of the chamber 102. Also, the size of the air inlet 104 is selected for optimizing cyclonic movement of the air flow entering the first separation chamber 104 in the example embodiment. it will be appreciated that the relevant dimensions may be adjusted accordingly in alternate embodiments depending on e.g. operating requirements.

In the example embodiment, the side wall 105 and a bottom face 302 of the first separation are molded together as a continuous single part. Sealing means 120, 18 e.g. a resilient elastomer, is provided on the bottom face 302 for sealingly engaging with a bottom circumference of the dust collector 116 (Figure 1). in an alternate embodiment, the bottom face 302 may be moided separately and mounted to the side wall 105 by a hinge mechanism (not shown) that controls the opening of the bottom face 302 for emptying the debris accumulated in the first separation chamber 102. Connecting members 304 are also provided on the sidewall 105 for coupling with the adaptor structure 124 {Figure 24) in the exampie embodiment.

Figure 4 shows a perspective view of a second separation chamber 112 according to an example embodiment. As can be seen from Figure 4, the second separation chamber 112 comprises a conical body 402 having a larger top end 404 and a smaller bottom end 408. Preferably, the draft angie of the conical body 402 is about 10°. However, it will be appreciated that different draft angle values may be used in alternate embodiments,

In the example embodiment, an air inlet 114 is disposed substantially horizontal and tangential with respect to the top end 404. In a preferred embodiment, the tangential direction of the inlet 114 fo the second separation chamber 112 is the same as the tangential direction of the iniet 104 to the first separation chamber 102, e.g. both clockwise. That is, the directions of the spiral motions with the first and second separation chambers 102, 112 respectively are preferably the same, e.g. clockwise. This may advantageously help to enhance the efficiency of the system in the example embodiment. The bottom end 4086 is open and typically rests within the dust collector 116 (Figure 1). In addition, sealing means 122s provided adjacent to the bottom end 406 for forming an air-tight seat with the dust collector 1186.

Also, in the example embodiment, a flange 408 is formed just below the air inlet 114 for securing the shroud 108 (Figure 1). As described above with respect to

Figure 2C, the conical body 402 is inserted through an inner ring of the shroud 108 during assembly. The flange 408 advantageously provides a snap-fit between a channel 410 disposed just above the flange 408 and the inner ring, as appreciated by persons skilied in the relevant art. The radially extended air iniet 114 and the flange 408 together advantageously secure the shroud 108 from axial movement with respect to the second separation chamber 112.

Figure 5 shows a perspective view of a fine dust collector 116 according to an example embodiment. The dust collector 116 comprises a substantially conical body 502 having a flat top face 508 and a hollow bottom face (not shown) in the example embodiment. However, it will be appreciated that a cylindrical body, for example, can be used in alternate embodiments. A circular opening 504 is provided on the top face 506 of the dust collector 116 for receiving the bottom end 406 of the second separation chamber 112 (Figure 3). in addition, the opening 504 sealingly engages with the sealing means 122 provided near the bottom end 408 of the second separation chamber 112, as described above. Also, in the example embodiment, a circumference 508 of the hollow bottom face sealingly engages with the sealing means 120 provided on the first separation chamber 102 (Figure 1), as described above.

Figure 6 shows a perspective view of a shroud 108 according to an example embodiment. The shroud 108 comprises an annular disk of a porous material 610 fixed to a support structure 800 comprising an outer ring 602, an inner ring 604 and a plurality of link members 806 connecting the outer ring 602 to the inner ring 804. In a preferred embodiment, the porous material 610 comprises a thin layer of nylon mesh. The hole area and hole size may be determined based on e.g. the desired air flow rate. For example, in the example embodiment, the hole size is about 425 micrometers (micron), the thread diameter is about 200 micron, giving a mesh count of about 16 per centimeter, and the hole area is about 46% of the total mesh area. it will be appreciated that the relevant dimensions may be adjusted accordingly in alternate embodiments depending on e.g. operating requirements.

As described above with respect to Figure 4, the inner ring 604 snap fits info the channel 410 (Figure 4), thereby securing the shroud 108 io the second separation chamber 112 (Figure 1). Preferably, the support structure 600 prevents a pressure difference existing between the first separation chamber 102 and space 108 (Figure 9) from deforming the porous material 810. Thus, if the flow direction is upwards, the porous material 610 is preferably fixed to the bottom face of the support structure 600. In an alternate embodiment, the porous material 610 and the support structure 600 may be integrally formed, e.g. as single perforated plastic or metal plate.

Figure 7 shows a perspective view of a top cover 110 according to an example embodiment. As can be seen from Figure 7, the top cover 110 comprises an alignment element provided on the inside of its top face for securing the second separation chamber 112 (Figure 1). In the example embodiment, the alignment element is In the form of a C-shaped circular protrusion 702 having an opening matching a width of the air inlet 114 (Figure 4) of the second separation channel 112. Thus, once the top end 404 (Figure 4) of the second separation chamber 112 abuts the top cover 110 and the inner wall of the protrusion 702, the second separation chamber 112 is prevented from axial or rotational movement with respect to the top cover 110. This advantageously reduces vibration and/or noise in this example embodiment,

In the example embodiment, the top cover 110 further comprises a first rim 704 that engages with the outer ring 602 of the shroud 108 (Figure 8) to additionally secure the shroud 108, and a second rim 708 that tightly engages (e.g. press fit) with the top circumference of the first separation chamber 102. In the example embodiment, the top cover 110 is preferably made of a plastic material, e.g.

polyvinyl chlorine (PVC). As will be appreciated by a person skilled in the art, a thin lining of rubber may be provided at e.g. the rim 706 to ensure a tight fit with the first separation chamber. In addition, one or more external locks/latches (not shown) are provided in the example embodiment to secure the top cover 110 to the first separation chamber 102.

As can be further seen from Figures 2B and 7, an outlet 118 of the cover 110 preferably extends downward info the second separation chamber 112 to avoid removing air that has just entered the second separation chamber 112 (i.e. stil containing fine dust particles). In the example embodiment, outlet 118 is advantageously formed integral with the top cover 110 to reduce vibration,

Figure 8A shows an image of a prototype of the above system for separating dirt from air according to an example embodiment. Figure 8B shows an alternate 16 view of the prototype of Figure 8A. Like numerals have the sama meanings as those provided in Figures 1-7.

As can be seen from the prototype, the inlet 104 to the first separation chamber 102 is adapted to receive an end of a typical hose or pipe. The first separation chamber 102 is made of a transparent plastic as described above such that the contents and parts within the first separation chamber 102 can be clearly seen. This may be useful for operating and maintaining the system, e.g. when the chamber 102 is filled with debris, or when the shroud 108 is clogged. Alse, in the prototype, the dust collector 116 is formed in a conical shape.

Figure © shows an image of an optional filter 900 according to an example embodiment. Figure 10 shows an image of the prototype of Figure 8A with the optional filter 800 of Figure 9. The filter 900 in the example embodiment comprises a layer of filter material 910 removably mounted to a support structure 124 which is of 3C¢ a similar construction as the support structure 800 described above with respect {©

Figure 8. As can be seen from Figure 10 the filter 900 is disposed above the outlet 118 to further filter any remaining dirt particles. The filter material 910 is typically obtained as a standard, off-the-shelf part. Preferably, the filter material 910 is washable and holes in the filler material 910 used for the filter 300 are smaller than those in the porous material used for the shroud 108.

The filter 900 advantageously prevents remaining fine dirt particles from entering the mofor assembly (described below) at high speed and possibly damaging the parts such as motor fan. in addition, as the filter 900 is disposed outside of the chambers 102 and 112 in the example ambodiment, the filter 900 can be easily reached and removed for cleaning/washing, if required, without having to dissembie the system 100. This advantageously helps fo simplify maintenance of the system in the example embodiment.

Figure 11A shows an image of a front side of a motor assembly 1100 according fo an example embodiment. Figure 118 shows an image of a back side of the motor assembly 1100 of Figure 11A. Figure 11C shows a close-up image of a 16 cord winding sub-assembly 1106 of the motor assembly 1100 of Figure 11A. Figure 11D shows a close-up image of power button sub-assembly 1104 of the motor assembly 1100 of Figure 11A.

The motor assembly 1100 is used in conjunction with the system 100 as described above to form a vacuum cleaner in the exampie embodiment. Typically, the motor assembly 1100 houses a fan (not shown} that provides suction power to suck dirty air into the first separation chamber 102 (Figure 1) and moves substantially ciean air from the outlet 118 (Figure 1) through back grilles 1110 of the motor assembly 1100.

The power rating of the fan in the example embodiment is substantially similar to that of a typical vacuum cieaner, e.g. about 1600 Watts (W). The air may be further filtered, e.g. through a high efficiency particulate arresting (HEPA) filter as may be required by regulations, before being expelied through front grilles 1102. The power button sub- assembly 1104 and the cord winding sub-assembly 1106 mounted to the motor assembly 1100 are similar to those found in conventional vacuum cleaners, and are thus not described in detail herein. in addition, a plurality of wheels 1108 are mounted to the bottom of the motor assembly 1100 to facilitate movement of the vacuum cleaner across a floor.

Figure 12 shows an image of a vacuum cleaner 1200 during assembly according to an example embodiment. In the vacuum cleaner 1200 of the example embodiment, the separation system 100 is disposed horizontally adjacent to the motor assembly 1100 to provide greater stability as a result of a tower center of gravity. However, it will be appreciated that a vertical arrangement is possibile in alternative embodiments, e.g. positioning the separation system vertically above the motor assembly 1100. Also, as can be seen from Figure 12, an air channel 1202 is formed fo link the separation system 100 and the motor assembly 1100.

With reference to Figure 12, the operation of the vacuum cleaner 1200 according to the example embodiment is now described. The fan inside the motor assembly 1100 draws dirty into the separation system via inlet 104. Inside the separation system 100, dirty air undergoes a 2-stage centrifugal separation process to successively separate large and fine dirt particles. Substantially clean air exits the system 100 at outlet 118 and moves through an optional filter S00. The clean air then moves across the air channel 1202 to the back grilles 1110 of the motor assembly 1100. inside the motor assembly, the air may be further filtered through a HEPA filler as may be required and/or used to cool the fan motor before being expelled through the front grilles 1102.

Figure 13 shows an image of the vacuum cleaner of Figure 12 with a top housing assembled according to an example embodiment. The housing 1302 provides structural support for the componenis of the vacuum cleaner as well as aesthetic appeal.

As described above, the system according the example embodiment uses relatively fewer parts than conventional systems. This may advantageously provide for simple manufacturing and maintenance. in addition, as the second separation chamber is disposed substantially within the first separation chamber and the shroud is horizontally positioned, the design may be advantageously compact. Also, as the shroud is horizontal, dirt particles that become temporarily stuck at the shroud during use preferably fali off under the effect of gravity after the system is switched

Off.

Furthermore, the air fiow in the space after the shroud preferably follows a spiral path before entering the second separation chamber, thereby eliminating the need fc use vanes io create cyclonic motion. It will aiso be appreciated that, as the shroud is positioned above the air inlet of the first separation chamber in the example embodiment, the shroud is advantageousiy less likely to be clogged by iarge dirt particles, which tend to spiral downwards fo be deposited at the base of the chamber.

Figure 14 shows a flow chart 1400 illustrating a method for separating dirt from air according to an example embodiment. At step 1402, at least some dirt particles are separated from the air flow in a first centrifugal separation chamber that receives the air flow. At step 1404, at ieast some of remaining dirt particles are separated from the air flow in a second centrifugal separation chamber disposed downstream from the first centrifugal separation chamber. At step 14086, a shroud is disposed between the first and second centrifugal separation chambers for preventing dirt particles having dimensions larger than a pore size of the shroud from leaving the first centrifugal separation chamber, wherein the shroud is disposed, in an operating > orientation, above an inlet for the air flow of the first centrifugal separation chamber.

Figure 15 shows a flow chart 1500 illustrating @ method for fabricating a system for separating dirt from an air flow according to an example embodiment. At step 1502, a first centrifugal separation chamber is provided for receiving the air flow to separate at least some dirt particles from the air flow. At step 1504, a second centrifugal separation chamber is provided downstream from the first centrifugal separation chamber for further separating at least some of remaining dirt particles from the air flow. At step 1508, a shroud is provided between the first and second centrifugal separation chambers for preventing dirt particles having dimensions larger than a pore size of the shroud from ieaving the first centrifugal separation chamber. At step 1508, the shroud is disposed, in an operating orientation, above an inlet for the air flow of the first centrifugal separation chamber. it will be appreciated by a person skilled in the art that numerous variations and/or modifications may be made to the present invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described.

The present embodiments are, therefore, to be considered in all respects to be iliustrative and not restrictive.

Claims (1)

1. A system for separating dirt from an air flow, the system comprising: a first centrifugal separation chamber for receiving the air flow to separate at least some dirt particles from the air flow; a second centrifugal separation chamber disposed downstream from the first centrifugal separation chamber for further separating at least some of remaining dirt particles from the air flow; and a shroud disposed between the first and second centrifugal separation chambers for preventing dirt particles having dimensions larger than a pore size of the shroud from ieaving the first centrifugal separation chamber, wherein the shroud is disposed, in an operating orientation, above an iniet for the air flow of the first centrifugal separation chamber.

2. The system as claimed in claim 1, wherein the inlet of the first centrifugal separation chamber is disposed substantially tangential to a side wali of the first centrifugal separation chamber.

3. The system as claimed in claims 1 or 2, wherein an inlet of the second centrifugal separation chamber is disposed substantially tangential to a side wall of the second centrifuga! separation chamber. 4, The system as claimed in claims 2 or 3, wherein the inlets are tangential in a clockwise manner.

5. The system as claimed in any one of the preceding claims, wherein the shroud is disposed substantially horizontally, in the operating orientation.

8. The system as claimed in any one of the preceding claims, wherein the first centrifugal separation chamber is made of a transparent material.

7. The system as claimed in any one of the preceding claims, wherein the first centrifugal separation chamber is substantially cylindrical.

8. The system as claimed in any one of the preceding claims, wherein the second centrifugal separation chamber comprises an inverted cone.

9. The system as claimed in claims 7 or 8, wherein the first centrifugal separation chamber and the second centrifugal separation chamber are substantially co-axial.

10. The system as claimed in ciaim 9, wherein the second centrifugal separation chamber is disposed substantially within the first centrifugal separation chamber.

11. The system as claimed in claim 10, wherein the shroud comprises an annutar disk separating the outlet of the first centrifugal separation chamber and the inlet of the second centrifugal separation chamber.

12. The system as claimed in any che of the preceding claims, wherein the shroud comprises a nylon mesh.

13. The system as claimed in any one of the preceding claims, further comprising a filter disposed at an outlet of the second centrifugal separation chamber. 14, A vacuum cleaner comprising the system as claimed in any one of claims 1 fo 13. 15, The vacuum cleaner as claimed in claim 14, further comprising a motor compariment disposed horizontally adjacent to said system.

16. A method for separating dirt from an air flow, the method comprising the steps of separafing at least some dirt particles from the air flow in a first centrifugal separation chamber that receives the air flow;

further separating at least some of remaining dirt particies from the air flow in a second centrifugal separation chamber disposed downstream from the first centrifugal separation chamber; and disposing a shroud between the first and second centrifugal separation chambers for preventing dirt particles having dimensions larger than a pore size of the shroud from leaving the first centrifugal separation chamber, wherein the shroud is disposed, in an operating orientation, above an inlet for the air flow of the first centrifugal separation chamber.

17. A method for fabricating a system for separating dirt from an air flow, the method comprising: providing a first centrifugal separation chamber for receiving the air flow to separate at least some dirt particies from the air flow: providing a second centrifugal separation chamber downstream from the first centrifugal separation chamber for further separating at least some of remaining dirt particles from the air flow; providing a shroud between the first and second centrifugal separation chambers for preventing dirt particles having dimensions iarger than a pore size of the shroud from leaving the first centrifugal separation chamber; and disposing the shroud, in an operating orientation, above an inlet for the air fiow of the first centrifugal separation chamber.