Suction cleaner

Abstract

With reference to Figure 4, we provide a suction cleaner, including: a nozzle defining a suction inlet; a motor for creating a suction flow of air through the cleaner between the suction nozzle and an exhaust outlet; a separator assembly for separating dirt from the air flow between the suction inlet and the motor; and an exhaust assembly for separating fine contaminants from the air flow between the motor and the exhaust outlet, the exhaust assembly including a filter having a filter housing defining a filter inlet opening having a first cross- sectional area and a filter outlet opening having a second cross-sectional area, and including a filter medium, wherein the first cross-sectional area of the filter inlet is less than the second cross-sectional area of the filter outlet.

Description

[0001] This invention relates to a suction cleaner, and particularly (but not exclusively) to a floor-standing upright vacuum cleaner.

[0002] Suction cleaning devices provide motors for establishing flow of air through the device, to transport air and entrained dirt from a suction mouth formed at the floorhead of the cleaner, or from the mouth of a suction hose or cleaning tool connected to the device, to an exhaust outlet for expelling air from the device. The air with entrained dirt is drawn through a separator assembly, removing coarse dirt from the air flow, and a substantial proportion of fine dirt, for storage within a dirt bin. The filtered air is drawn through the motor and is subsequently expelled from the device via the exhaust outlet.

[0003] It is common that air passing through the cleaner is heated by the motor and so is warmer than the ambient air when exhausted. In addition, exhaust outlets of a cleaner may be considered unsightly compared to other surfaces of the cleaner, since they may provide a view of internal parts of a cleaner which would preferably be hidden from view.

[0004] US 2019 / 111373A1 describes a filter assembly for a vacuum cleaner. The filter assembly has a housing, a filter medium disposed in the housing, a recess formed in a surface of the housing, a tab movable between a first position and a second position, and a fixing member movable between a fixing position and a release position. The fixing member is engageable with the vacuum cleaner when in the fixing position to fix the filter assembly to the vacuum cleaner. The fixing member is disengageable from the vacuum cleaner when in the release position such that the filter assembly may be removed from the vacuum cleaner. The tab is movable between the first and second positions to move the fixing member between the fixing and release positions. The tab is disposed within the recess such that the tab is located below the surface of the housing in the first position.

[0005] The present invention seeks to reduce or overcome one or more of the deficiencies associated with the prior art.

[0006] Suction cleaning devices of the prior art often address the issues by minimising the appearance of exhaust outlets so that they cover a small surface area of the cleaner, to avoid detracting from the design aesthetic of the cleaner. The exhaust outlets are often positioned on a portion of the device facing away from a user during use, such as on an underside of the device, wrapped around the sides of the device, with a goal of directing exhausted air away from the user. In this way, the discomfort of a user may be minimised, due to the reduction or avoidance of exhausted air hitting the user as the device is operated.

[0007] However, there are drawbacks associated with minimising the appearance of exhaust outlets, and with repositioning them in order to direct air away from the user. For example, reducing the surface-area of the outlets, when expelling a given volume of air, results in an increased velocity of air leaving the cleaner. Further, providing convoluted routing of exhaust ducting within the cleaner body results in increasing the operating temperature of the device as a whole, as warmed air is effectively recirculated within the body of the cleaner.

[0008] According to a first aspect of the invention, we provide a suction cleaner, including: a nozzle defining a suction inlet; a motor for creating a suction flow of air through the cleaner between the suction nozzle and an exhaust outlet; a separator assembly for separating dirt from the air flow between the suction inlet and the motor; and an exhaust assembly for separating fine contaminants from the air flow between the motor and the exhaust outlet, the exhaust assembly including a filter having a filter housing defining a filter inlet opening having a first cross-sectional area and a filter outlet opening having a second cross-sectional area, and including a filter medium, wherein the first cross-sectional area of the filter inlet is less than the second cross-sectional area of the filter outlet, wherein the filter housing defines a volume between the filter inlet opening and the filter outlet opening, wherein the filter housing provides at least one support extending within the volume defined by the filter housing, a portion of the support lying against a portion of the first filter medium, and wherein the filter housing provides a plurality of supports, configured such that the first filter medium disposed across the filter outlet opening is contacted in a plurality of positions by the supports.

[0009] The first filter medium may be disposed across substantially the entire filter outlet opening.

[0010] The filter inlet opening may be provided with a second filter medium.

[0011] At least a portion of the volume defined by the housing may contain a third filter medium.

[0012] The filter housing supports may be configured such that air entering the filter housing via the filter inlet is permitted to leave the filter housing via any portion of the filter medium disposed across the filter outlet other than where it is in direct contact with the supports.

[0013] The filter may be removable from the suction cleaner without the use of tools.

[0014] The filter may further provide a releasable securing mechanism configured to hold the filter in situ, such that the filter inlet opening faces an outlet of the motor.

[0015] The motor may provide a motor housing and an exhaust grill covering its outlet, such that air leaves the motor via the exhaust grill.

[0016] The ratio of the second cross-sectional area of the filter outlet to the first cross-sectional area of the filter inlet may be in the range of 1.1:1, to 10:1. The ratio may be in the range of 1.5:1, to 8:1, or in the range of 2:1 to 6:1, or in the region of 4:1.

[0017] The exhaust assembly may further include an exhaust cover downstream of the filter outlet, the exhaust cover defining the exhaust outlet.

[0018] The exhaust outlet may be defined by a plurality of openings in the exhaust cover.

[0019] The filter outlet opening may lie in a filter plane, and the openings of the exhaust outlet extend through the exhaust cover in a direction substantially parallel to the filter plane.

[0020] According to a second aspect of the invention we provide a filter for separating fine contaminants from the air flow downstream of a suction motor of a vacuum cleaner, including: a filter housing defining a filter inlet opening having a first cross-sectional area and a filter outlet opening having a second cross-sectional area, and a filter medium, wherein the first cross-sectional area of the filter inlet is less than the second cross-sectional area of the filter outlet, wherein the filter housing defines a volume between the filter inlet opening and the filter outlet opening, and wherein a plurality of supports extend within the volume, configured such that the first filter medium disposed across the filter outlet opening is contacted in a plurality of positions by the supports.

[0021] The first filter medium may be disposed across substantially the entire filter outlet opening, and the filter inlet opening is provided with a second filter medium.

[0022] The filter housing supports may be configured such that air entering the filter housing via the filter inlet is permitted to leave the filter housing via any portion of the filter medium disposed across the filter outlet other than where it is in direct contact with the supports.

[0023] The ratio of the second cross-sectional area of the filter outlet to the first cross-sectional area of the filter inlet may be in the range of 1.1:1, to 10:1, or in the range of 1.5:1, to 8:1, or in the range of 2:1 to 6:1, or may be in the region of 4:1.

[0024] According to a third aspect of the invention we provide an exhaust assembly for a vacuum cleaner, comprising a filter according to the second aspect of the invention, and an exhaust cover downstream of the filter outlet, the exhaust cover defining an exhaust outlet.

[0025] The exhaust outlet may be defined by a plurality of openings in the exhaust cover, and the filter outlet opening lies in a filter plane, and the openings of the exhaust outlet may extend through the exhaust cover in a direction substantially parallel to the filter plane.

[0026] Embodiments of the technology will now be described, by way of example only, with reference to the following figures, of which: Figure 1 is a side view of a suction device according to embodiments of the technology; Figure 2 is a rear view of the device illustrated in Figure 2; Figure 3 is a perspective view of a portion of the upright body of the suction device of Figure 1, shown with the separator assembly removed from the device; Figure 4 is a side cross-section through a portion of the upright body and separator assembly of the suction device; Figure 5 is a perspective cut-away view of the motor and exhaust assembly of the suction device according to embodiments of the technology; and Figure 6 is an enlarged view of a portion of Figure 4, illustrating the relative sizes of components of the exhaust assembly.

[0027] With reference to the drawings, we provide a suction cleaner 10 for cleaning a surface. The cleaner illustrated in this example embodiment is a floor-standing upright cleaner, although it should be understood that aspects of the invention may be applied to other types of suction cleaner, and in particular floor-standing cleaners, such as a canister type cleaner, or a cylinder cleaner, for example.

[0028] In general terms, and with reference to Figures 1, 2 and 3, we describe a suction cleaner 10 with a floor head 14 providing a nozzle that defines a suction inlet (or suction mouth) for applying a suction force to a surface being cleaned. A motor 40 creates a suction flow of air through the cleaner 10 between the suction nozzle and an exhaust outlet 26.

[0029] The suction cleaner 10 provides a separator assembly 18 for separating dirt from the air flow between the suction inlet and the motor 40, and an exhaust assembly 50 for separating fine contaminants from the air flow between the motor 40 and the exhaust outlet 26.

[0030] The exhaust assembly 50, described in detail below, includes a post-motor filter 58 having a filter housing 68 defining a filter inlet opening 55 having a first cross-sectional area and a filter outlet opening 66 having a second cross-sectional area, and includes a filter medium 65.

[0031] The first cross-sectional area of the filter inlet opening 55 is less than the second cross-sectional area of the filter outlet opening 66. This means that the flow of air entering the filter inlet opening 55 is dispersed over a larger area when exiting the filter housing 68 via the filter outlet opening 66. This causes the fluid flow rate to drop so that the air exiting the filter 58 is moving relatively slowly. Furthermore, the dissipation of the air flow throughout the interior of the filter housing, from a relatively small inlet to a relatively large outlet means that any fine dirt entrained in the airflow is spread over and deposited across a larger surface area at the outlet.

[0032] Dissipating the air flow and dirt in this manner provides a filter which traps a greater proportion of the dirt particles from the air flowing through the filter, in addition to slowing the air speed of the air leaving the filter, so that it is relatively slower when leaving the suction cleaner 10 via the exhaust outlet 26.

[0033] In the embodiment illustrated, the suction cleaner 10 comprises an upright body 12 providing a handle portion 16 including a first user-graspable handle 30 to allow a user to operate and steer the device. The floor head 12 provides rollers 20 (e.g. wheels) for moving the suction cleaner 10 across a surface.

[0034] The floor head 14 provides one or more agitators for dislodging dirt from the floor surface and a floor head outlet from which air and entrained dirt are drawn from the floor head towards a separator assembly 18 via a suction passage 36. The suction passage 36 fluidly connects the floor head 14 to an inlet of the separator assembly 18. An outlet of the separator assembly 18 fluidly connects the separator assembly 18 to the motor 40, via which a suction air flow is generated within the suction cleaner, so as to draw air and entrained dirt through the floor head 14, to the separator assembly 18, and to draw cleaned air from the separator assembly 18. An exhaust outlet 26 vents air from the suction device 10, downstream of the motor 40.

[0035] In embodiments, and as shown in Figure 3, the separator assembly 18 comprises a housing 22 that provides a collecting volume 48 for collecting dirt separated from the incoming air flow. The housing 22 also contains a separator, which in embodiments is formed of a first stage cyclonic separator 44 to remove large particles of dirt, and a second stage cyclonic separator 46 for removing smaller particles of dirt from the air flow. In embodiments, and as shown, the first stage separator 44 provides a mesh shroud for filtering relatively large particles, and the second stage separator 46 provides a plurality of cyclonic separators, each formed as a cone shape as is known in the art, for filtering fine dirt particles from the air flow.

[0036] In embodiments, the separator assembly 18 is mounted on a portion 34 of the upright body 12 during use, but is detachable from the body 12 for the purpose of emptying the dirt from the separator assembly collecting volume 48. The separator assembly 18 may further include a pre-motor filter 52 (comprising a filter material layer 62) positioned downstream of the separator stages described above. In embodiments this pre-motor filter 52 is housed within a removable lid portion 24 of the housing 22. In this way, the removable lid portion 24 may be detached to expose the filter 52 for cleaning. The lid portion 24 may further provide a handle 32 to allow a user to lift away the housing 22 when detached from the upright body 12 of the cleaner.

[0037] The body 12 further provides a power source, which in embodiments is a rechargeable battery pack 31. The battery pack 31 may be rechargeable in situ, or when removed from the body 12, as is known in the art. Alternatively, or in addition, the suction cleaner 10 may be provided with a power cable for connection to a mains power source.

[0038] The body 12 further includes a carrying handle 28 configured to enable a user to lift and carry the device 10.

[0039] A motor inlet 38 communicates with the outlet of the separator assembly 18 when it is mounted on the upright body 12 of the suction cleaner 10. Air is drawn into a motor housing 60 of the motor 40 via the motor inlet 38, and expelled through a motor outlet 54. A grill is provided at the motor inlet 38 and at the motor outlet 54 to allow air to flow through the motor housing between the inlet 38 and outlet 54 during operation of the motor. Typically, even though the air passing through the separator assembly 18 has passed through the primary separator (and in the described example, through a secondary stage of separation), and through a pre-motor filter, very small particles of dirt contaminate the air drawn through the motor 40. This means that the air exhausted via the motor outlet 54 is expected to contain some level of contamination due to these tiny particles.

[0040] To address or minimise the issues caused by dirt particles remaining in the air leaving the motor, the exhaust assembly 50 is provided. The exhaust assembly 50 lies downstream of the motor 40, to filter tiny particles from the air flow leaving the motor outlet 54, so that the air leaving the suction cleaner 10 via the exhaust assembly 50 is relatively clean. In this way, the air leaving the suction cleaner is purer than would otherwise be the case. Further, as previously described, the configuration of the filter 58 allows the air speed to reduce as it passes through the filter housing 68, thereby resulting in a slower air speed as the air is exhausted from the suction cleaner 10.

[0041] The exhaust assembly 50 includes a post-motor filter 58 and an exhaust cover 57 downstream of the motor outlet 54, the exhaust cover 57 defining one or more exhaust outlets 26. As shown, preferably the exhaust cover 57 defines a plurality of exhaust outlets 26.

[0042] The filter 58 provides a filter housing 68 formed by a frame. The frame provides a rim 70 which is configured to sit against a portion of the body 12 of the suction cleaner 10, so as to locate the filter correctly relative to the motor 40. In embodiments, portions of the rim 70 provide a lip or projection, configured to engage with a corresponding ridge or recess in the body 12.

[0043] The filter housing 68 defines the filter inlet opening 55 at one side of the housing, and the filter outlet opening 66 on the opposing side of the housing. A volume is defined between the inlet and the outlet, within the frame. The filter inlet opening 55 defines a first cross-sectional area and the filter outlet opening 66 defines a second cross-sectional area, which is larger than the first cross-sectional area. This means that the flow of air entering the filter inlet opening 55 is dispersed over a larger area when exiting the filter housing 68 via the filter outlet opening 66.

[0044] In embodiments, a filter medium 65 is disposed across substantially the entire filter outlet opening 66. A second filter medium 53 may be disposed across the filter inlet opening 55. It should be understood that the term 'opening' refers to a fluid-permeable opening, which in the case of a filter medium as described, allows air to flow through the opening. The opening may nevertheless inhibit or prevent movement of solid particles through the opening, into or out of the filter housing 68. The filter media may be mesh material, a woven material, a foam material or any other suitable porous material as is known in the art.

[0045] In embodiments, the filter medium 65 at the filter outlet opening 66 and / or the filter medium 53 at the filter inlet opening 55 may be removable from the filter housing 68. In other embodiments, the filter media 53, 65, are fixed in place relative to the filter housing 68.

[0046] As described above, a first cross-sectional area, of the filter inlet opening 55, is less than a second cross-sectional area, of the filter outlet opening 66. Correspondingly, the surface area of the filter medium 53 at the filter inlet opening 55 is smaller than the surface area of the filter medium 65 at the filter outlet opening 66. In embodiments, the ratio of the second cross-sectional area of the filter outlet opening 66 to the first cross-sectional area of the filter inlet opening 55 is in the range of 1.1:1, to 10:1. In embodiments, the ratio is in the range of 1.5:1, to 8:1, or in the range of 2:1 to 6:1, or in the region of 4:1.

[0047] To achieve the increased surface area of the filter outlet opening 66, the filter housing 68 has a curved profile which extends from a relatively short height / length denoted A in Figure 6 at the filter inlet opening 55, to a relatively tall height / length denoted B at the filter outlet opening. The ratio of the height / length of the inlet opening to the outlet opening, A:B, is < 1:1. Preferably the ratio is less than 1:2, and more preferably still the ratio is around 1:3. To fit within the body 12 of an upright suction cleaner of the type described, it is preferable for the filter 58 to be tall and thin, to make use of the otherwise unused space within the rear of the upright body 12. In this way, the air flow leaving the motor 40 can be dissipated over a relatively large surface area within the body 12, before reaching the exhaust outlet(s) 26.

[0048] In embodiments, further filter material may be contained within the volume defined by the filter housing 68, between the inlet opening 55 and outlet opening 66, to inhibit or prevent passage of fine dirt through the filter 58. The filter material may substantially fill the volume within the housing, or may be spaced out within the volume, or only in a portion of the volume.

[0049] In embodiments, the filter outlet opening 66 is formed in a plane, referred to herein as the "filter plane". The filter medium 65 at the filter outlet opening 66 therefore lies substantially flat, across the opening, in the filter plane.

[0050] In embodiments, the filter housing 68 provides at least one support 74 extending within the volume defined by the housing 68. Preferably, the filter 58 provides a plurality of supports 74, formed as struts or walls extending into the volume formed within the filter housing 68, from a wall of the housing 68. The supports 74 are preferably formed integrally with the frame of the filter. One of more of the supports 74 has a portion which lies against or otherwise abuts a portion of the filter medium 65 disposed at the filter outlet opening 66. In this way, the supports 74 assist in maintaining the shape of the filter 58, so that the filter medium 65 at the filter outlet lies substantially flat across the filter plane defined by the filter outlet opening 66. Where the filter outlet opening 66 is significantly larger than the filter inlet opening 55, the additional support provided by these supports 74 can be particularly advantageous.

[0051] In embodiments, the filter medium 65 disposed across the filter outlet opening is contacted in a plurality of positions by the supports 74. In embodiments, the filter medium 53 at the inlet opening 55 is contacted by the supports 74 which serve to maintain the shape of the filter medium 53 at the filter inlet opening 55, also lying in a flat plane.

[0052] In embodiments, the supports 74 are configured such that air entering the filter housing 68 via the filter inlet opening 55 is permitted to leave the filter housing 68 via any portion of the filter medium 65 disposed across the filter outlet opening 66 other than where it is in direct contact with the supports 74. In other words, the supports 74 do not extend the full width of the filter housing 68 - between the inlet and outlet - thus allowing air to flow over and around the supports 74 as it moves from the inlet to the outlet. The supports 74 may be curved in profile, as illustrated in Figure 5, for example. In this way, the supports 74 provide structure within the filter housing 68, to assist in maintaining the structural rigidity of the filter housing 68, and / or to assist in maintain the shape of the filter media 53, 65, disposed across the inlet and outlet. Further, in embodiments in which further filter media is provided within the volume of the filter housing 68, the supports 74 assist in maintaining the distribution of that filter material throughout the volume, or confining it to parts of the volume.

[0053] Preferably, the filter 58 is removable from the suction cleaner 10 without the use of tools. In embodiments and as shown in the figures, the filter 58 provides a releasable securing mechanism 72 configured to hold the filter 58 in situ when installed in the cleaner. The filter housing 68 provides a resiliently-biased latching formation (which may be formed integrally with the housing) for engaging part of the body of the suction cleaner 10 when installed in position. A user may depress a portion of the latching part to move it from its engaged position, thus disengaging the latch from a detent formed in the body, so that the user can remove the filter 58. When installed, the filter inlet opening 55 faces the outlet 54 of the motor 40, so that air leaving the motor via the motor outlet 54 is directly incident on the filter inlet opening 55.

[0054] In embodiments, the exhaust outlet 26 is defined by a plurality of openings in the exhaust cover 57. These openings may be provided in the form of a grill, for example, through which the air flow passes. The air passing through the post-motor filter 58 leaves the filter housing 68 through the filter outlet opening 55, in a direction generally perpendicular to the filter plane.

[0055] The exhaust cover 57 substantially covers the rear of the cleaner directly downstream of the post-motor filter 58. In embodiments, and as shown in the figures, the openings forming the exhaust outlet 26 extend through the exhaust cover 57 in a direction substantially parallel to the filter plane. In this configuration, described in terms of the orientation of the cleaner shown in the Figures - in which the body of the cleaner is disposed in its upright position - the air leaving the filter 58 travels backwards towards the exhaust cover 57. The exhaust outlets 26 are situated on either side of the exhaust cover 57, oriented substantially sideways to the direction of travel of the cleaner 10, so that the air follows a path angled through approximately 90 degrees in order to exit the body of the suction cleaner 10 via the exhaust outlets 26.

[0056] In embodiments, the exhaust cover 57 is removably connected to the body 12 of the suction cleaner 10. The exhaust cover 57 provides a release mechanism operable by a user to remove the cover without using tools. For example, the mechanism may provide a resiliently deformable latch similar to that described in relation to the filter.

[0057] When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

[0058] 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.

[0059] Although certain example embodiments of the invention have been described, the scope of the appended claims is not intended to be limited solely to these embodiments. The claims are to be construed literally, purposively, and / or to encompass equivalents.

Claims

1. A suction cleaner (10), including: a nozzle defining a suction inlet; a motor (40) for creating a suction flow of air through the cleaner between the suction nozzle and an exhaust outlet (26); a separator assembly (18) for separating dirt from the air flow between the suction inlet and the motor; and an exhaust assembly (50) for separating fine contaminants from the air flow between the motor and the exhaust outlet, the exhaust assembly including a filter (58) having a filter housing (68) defining a filter inlet opening (55) having a first cross-sectional area and a filter outlet opening (66) having a second cross-sectional area, and including a first filter medium (65), wherein the first cross-sectional area of the filter inlet is less than the second cross-sectional area of the filter outlet, and wherein the filter housing (68) defines a volume between the filter inlet opening and the filter outlet opening, the filter housing (68) providing a plurality of supports (74) extending within the volume defined by the filter housing, and configured such that the first filter medium (65) disposed across the filter outlet opening (66) is contacted in a plurality of positions by the supports (74).

2. A suction cleaner according to claim 1, wherein the filter housing supports are configured such that air entering the filter housing via the filter inlet is permitted to leave the filter housing via any portion of the first filter medium disposed across the filter outlet other than where it is in direct contact with the supports.

3. A suction cleaner according to claim 1 or claim 2, wherein the first filter medium is disposed across substantially the entire filter outlet opening.

4. A suction cleaner according to any preceding claim, wherein the filter inlet opening is provided with a second filter medium (53).

5. A suction cleaner according to any preceding claim, wherein at least a portion of the volume defined by the housing contains a third filter medium.

6. A suction cleaner according to any preceding claim, wherein the filter is removable from the suction cleaner without the use of tools; and / or wherein the filter further provides a releasable securing mechanism configured to hold the filter in situ, such that the filter inlet opening faces an outlet of the motor; and / or wherein the motor provides a motor housing and an exhaust grill covering its outlet, such that air leaves the motor via the exhaust grill.

7. A suction cleaner according to any preceding claim, wherein the ratio of the second cross-sectional area of the filter outlet to the first cross-sectional area of the filter inlet is in the range of 1.1:1, to 10:1, or wherein the ratio is in the range of 1.5:1, to 8:1, or wherein the ratio is in the range of 2:1 to 6:1, or wherein the ratio is 4:1.

8. A suction cleaner according to any preceding claim, wherein the exhaust assembly further includes an exhaust cover (57) downstream of the filter outlet, the exhaust cover defining the exhaust outlet.

9. A suction cleaner according to claim 8, wherein the exhaust outlet is defined by a plurality of openings in the exhaust cover.

10. A suction cleaner according to claim 9, wherein the filter outlet opening lies in a filter plane, and the openings of the exhaust outlet extend through the exhaust cover in a direction substantially parallel to the filter plane.

11. A filter (58) for separating fine contaminants from the air flow downstream of a suction motor (40) of a vacuum cleaner, including: a filter housing (68) defining a filter inlet opening (55) having a first cross-sectional area and a filter outlet opening (66) having a second cross-sectional area, and a first filter medium (65), wherein the first cross-sectional area of the filter inlet is less than the second cross-sectional area of the filter outlet, wherein the filter housing defines a volume between the filter inlet opening and the filter outlet opening, and wherein a plurality of supports (74) extend within the volume, configured such that the first filter medium disposed across the filter outlet opening is contacted in a plurality of positions by the supports.

12. A filter according to claim 11, wherein the filter housing supports are configured such that air entering the filter housing via the filter inlet is permitted to leave the filter housing via any portion of the first filter medium disposed across the filter outlet other than where it is in direct contact with the supports.

13. A filter according to claim 11 or claim 12, wherein the first filter medium is disposed across substantially the entire filter outlet opening, and the filter inlet opening is provided with a second filter medium (53).

14. A filter according to any one of claims 11 to 13, wherein the ratio of the second cross-sectional area of the filter outlet to the first cross-sectional area of the filter inlet is in the range of 1.1:1, to 10:1, and preferably is in the range of 1.5:1, to 8:1, and more preferably is in the range of 2:1 to 6:1, and more preferably still is 4:1.

15. An exhaust assembly for a vacuum cleaner, comprising a filter according to any one of claims 11 to 14, and an exhaust cover (57) downstream of the filter outlet, the exhaust cover defining an exhaust outlet (26), optionally wherein the exhaust outlet is defined by a plurality of openings in the exhaust cover, and wherein the filter outlet opening lies in a filter plane, and the openings of the exhaust outlet extend through the exhaust cover in a direction substantially parallel to the filter plane.

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