CYCLONIC SEPARATING APPARATUS

Abstract

A cyclonic separating apparatus for separating particles from a dirt-laden airflow includes a cyclone for separating and collecting dirt and dust from the dirt-laden airflow. The cyclone has an air inlet, an air outlet, a longitudinal axis and a wall. The wall includes a first portion and a second portion spaced farther from the longitudinal axis than the first portion, the first and second portions being spaced along the longitudinal axis. The cyclone also includes at least one lip extending from the first portion of the wall into a portion of the cyclone surrounded by the second portion of the wall. By providing a cyclone with a wall having two portions of different sizes and a lip extending from the portion with the smaller size into the portion with the larger size, the risk of blockages due to re-entrainment and movement of dirt and dust within the cyclonic separating apparatus is reduced.

Description

REFERENCE TO RELATED APPLICATIONS

This application is a national stage application under 35 USC 371 of International Application No. PCT/GB2007/002525, filed Jul. 6, 2007, which claims the priority of United Kingdom Application No. 0614237.6, filed Jul. 18, 2006, the contents of which prior applications are incorporated herein by reference.

FIELD OF THE INVENTION

The invention relates to cyclonic separating apparatus particularly, but not exclusively, for a vacuum cleaner. More particularly, the invention relates to cyclonic separating apparatus for a hand-held vacuum cleaner.

BACKGROUND OF THE INVENTION

Cyclonic separating apparatus is known from, for example, EP 0 042 723. This document discloses a vacuum cleaner which separates particles from an airflow using two reverse flow cyclones. The cyclones comprise a first, low-efficiency cyclone and a second, high-efficiency cyclone downstream of the first cyclone. Dirt- and dust-laden air enters through an inlet in the first cyclone and follows a downward helical path around the interior of the first cyclone. Centrifugal forces act on the entrained dirt and dust to separate it from the airflow. When separated from the airflow, the dirt and dust collects at the base of the first cyclone. Upon reaching the base of the first cyclone, the airflow reverses direction. The partially-cleaned airflow moves back up the first cyclone and exits the first cyclone through an outlet. It is usual to provide a so-called shroud around the outlet from the first cyclone. The shroud comprises a wall with a large number of through-holes through which the airflow passes in order to reach the second cyclone. The air then enters the second cyclone and follows a downward helical path inside the second cyclone. Smaller particles are separated from the airflow in a similar fashion to the first cyclone and are deposited in a collector located beneath the second cyclone. The cleaned air then flows back up the interior of the second cyclone and passes sequentially through a pre-motor filter, a motor and a post-motor filter before being exhausted from the vacuum cleaner.

Occasionally, in this arrangement, some of the dirt and dust which has been separated from the airflow becomes re-entrained in the return airflow. This is undesirable because this dirt and dust may cause blockages in parts of the cyclonic separating apparatus such as the through-holes of the shroud. Blocking the through-holes of the shroud will reduce the efficiency at which the cyclonic separating apparatus operates.

In order to improve the retention of dirt and dust in the first cyclone upstream of the shroud, it is known to provide the shroud with a lip projecting into the first cyclone. An example of such a lip is shown and described in EP 0 800 359. This lip reduces the risk of the shroud through-holes becoming clogged or blocked.

However, whilst this solution is useful for cyclonic separating apparatus which is orientated substantially vertically (such as in an upright machine), this arrangement may be less effective for cyclonic separating apparatus which is orientated away from the vertical. Such a situation may arise when, for example, the cyclonic separating apparatus is arranged at an angle to the vertical in a cylinder machine or forms part of a hand-held vacuum cleaner which may be held at an arbitrary angle by a user. In these circumstances, there is a risk that the separated dirt and dust will move towards the outlet of the first cyclone. This is undesirable because the dirt and dust may block the inlet or the through-holes in the shroud.

It is known to provide an inwardly-extending projection on the wall of a cyclone. EP 0 728 435 and GB 2 363 744 both show an inwardly-projecting annular collar or rib located around the lower part of the inner surface of such a cyclone. In both of these prior art disclosures, it is suggested that these features will help to prevent dirt and dust becoming re-entrained in the partially-cleaned airflow. However, the introduction of elements such as inwardly-projecting ribs or collars on the inner wall of a cyclone may also introduce unwanted effects. For example, these elements may generate turbulence within the cyclone which may disturb the deposited dirt and dust in an undesirable way. Further, the introduction of these elements can reduce the separation efficiency of the cyclone.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide cyclonic separating apparatus which reduces the risk of re-entrainment of dirt and dust separated from an airflow whilst minimising any detrimental effect on the separation efficiency of the cyclonic separating apparatus. It is a further object to provide cyclonic separating apparatus which minimises the risk of re-entrainment of dirt and dust separated from an airflow when the cyclonic separating apparatus is moved away from a vertical orientation.

The invention provides cyclonic separating apparatus for separating particles from a dirt- and dust-laden airflow comprising a cyclone for separating and collecting dirt and dust from the dirt- and dust-laden airflow, the cyclone having an air inlet, an air outlet, a longitudinal axis and a wall, the wall comprising a first portion and a second portion spaced further from the longitudinal axis than the first portion, the first and second portions being axially spaced along the longitudinal axis, wherein the cyclone further comprises at least one lip extending from the first portion of the wall into a portion of the cyclone surrounded by the second portion of the wall. By providing a cyclone with a wall having two portions of different sizes and a lip extending from the smaller portion into the larger portion, the risk of blockages due to re-entrainment and movement of dirt and dust within the cyclonic separating apparatus is reduced.

Preferably, the first portion of the cyclone is cylindrical and has a first radius. More preferably, at least a part of the second portion of the cyclone is cylindrical and has a second radius.

Preferably, the lip forms a substantially straight extension of the first portion of the wall. This arrangement minimises the protrusion of the lip into the airflow whilst still reducing the risk of re-entrainment of separated dirt and dust within the cyclonic separating apparatus.

Preferably, the cyclonic separating apparatus comprises at least one further cyclone and a collector which are located downstream of the air outlet, the at least one further cyclone being arranged to deposit separated dirt and dust into the collector. More preferably, the collector has a longitudinal axis, a wall and at least one further lip extending from the wall of the collector into the collector. By providing a lip extending from the wall of the collector, the risk of re-entrainment and migration of fine dirt and dust deposited in the collector can be minimised and thus the risk of the further cyclones becoming blocked is reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described with reference to the accompanying drawings, in which:

FIG. 1 shows a hand-held vacuum cleaner incorporating cyclonic separating apparatus according to a first embodiment of the invention;

FIG. 2 is a cross section through the cyclonic separating apparatus of the hand-held vacuum cleaner of FIG. 1 taken along a longitudinal axis thereof;

FIG. 3 is a lateral cross section through the cyclonic separating apparatus of the hand-held vacuum cleaner of FIG. 1; and

FIGS. 4 to 11 are schematic diagrams of alternative embodiments of part of the cyclonic separating apparatus according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a hand-held vacuum cleaner 10. The hand-held vacuum cleaner 10 has a main body 12 which houses a motor and fan unit (not shown). The main body 12 also includes a power source 14 such as a battery. A handle 16 is provided on the main body 12 for manipulating the hand-held vacuum cleaner 10 in use. Cyclonic separating apparatus 100 is attached to the main body 12. An inlet pipe 18 extends from a portion of the cyclonic separating apparatus 100 remote from the main body 12. A dirty air inlet 20 is formed at the distal end of the inlet pipe 18. A brush tool 22 is slidably mounted on the distal end of the inlet pipe 18. A set of exhaust vents 24 are provided on the main body 12 for exhausting air from the hand-held vacuum cleaner 10.

The cyclonic separating apparatus 100 forming part of the hand-held vacuum cleaner 10 is shown in more detail in FIGS. 2 and 3. The cyclonic separating apparatus 100 comprises a cyclone 102 which has a longitudinal axis X-X and a wall 104. The wall 104 comprises a first portion 106 and a second portion 108. An inlet 110 is formed in the wall 104 and arranged so that the first portion 106 of the wall 104 is located between the inlet 110 and the second portion 108 of the wall 104. The inlet 110 is in communication with the dirty air inlet 20 and forms a communication path between the inlet pipe 18 and the interior of the cyclone 102. The air inlet 110 is arranged tangentially to the cyclone 102 so that the incoming air is forced to follow a helical path around the interior of the cyclone 102.

The first portion 106 of the wall 104 is substantially cylindrical and is in two parts. This is so that the parts can be separated to allow cleaning of the interior of the cyclone 102. However, this is not material to the invention. The second portion 108 of the wall 104 is spaced further from the longitudinal axis X-X than the first portion 106 of the wall 104. The second portion 108 of the wall 104 includes a shoulder 112 and a cylindrical part 113. A lip 114 extends from the first portion 106 of the wall 104 into the space surrounded by the second portion 108 of the wall 104 of the cyclone 102. The lip 114 forms a substantially straight extension of the first portion 106 of the wall 104. The function of the lip 114 will be described later.

A base 116 closes one end of the cyclone 102. The base 116 is pivotably mounted on the lower end of the second portion 108 of the wall 104 by means of a hinge 118. The base 116 is retained in a closed position (as shown in FIGS. 1 to 3) by means of a catch 120.

A shroud 121 is located inwardly of the wall 104 of the cyclone 102. The shroud 121 comprises a cylindrical wall 122 having a plurality of through-holes 123. The shroud 121 surrounds an outlet 124 from the cyclone 102. The outlet 124 provides a communication path between the cyclone 102 and a further cyclone assembly 126. A lip 128 is provided at the base of the shroud 121. The lip 128 has a plurality of through-holes which are designed to allow air to pass through but to capture dirt and dust.

The further cyclone assembly 126 comprises a plurality of further cyclones 130 arranged in parallel. In this embodiment, six further cyclones 130 are provided. Each further cyclone 130 has a tangentially-arranged air inlet 132 and an air outlet 134. Each air inlet 132 and air outlet 134 is located at a first end of the respective further cyclone 130. A cone opening 136 is located at a second end of each further cyclone 130. The cone opening 136 of each further cyclone 130 is inclined with respect to a longitudinal axis (not shown) of the respective further cyclone 130 as can be best seen in FIG. 3. The cone openings 136 of each of the further cyclones 130 are in communication with a passageway 138 defined by a wall 140 located inwardly of the shroud 121.

A collector 142 is located at the lower end of the passageway 138. The collector 142 comprises a frustoconical first portion 144 and a cylindrical second portion 146. The interior of the collector 142 is surrounded by the base 116 and the sides of the first and second portions 144, 146 of the collector 142.

A further lip 148 extends into the portion of the collector 142 surrounded by the cylindrical second portion 146. The further lip 148 comprises a frustoconical portion 148a and a cylindrical portion 148b which extends substantially parallel to the sides of the second portion 146 of the collector 142. The function of the further lip 148 will be described later.

Each of the air outlets 134 of the further cyclones 130 is in communication with a duct 150. The duct 150 provides an airflow path from the cyclonic separating apparatus 100 into other parts of the hand-held vacuum cleaner 10. Located at the downstream end of the duct 150 is a pre-motor filter 152. The pre-motor filter 152 comprises a porous material such as foam.

In use, the motor and fan unit draws a flow of dirt-laden air into the dirty air inlet 20, through the inlet pipe 18 and into the cyclonic separating apparatus 100. Dirt-laden air enters the cyclonic separating apparatus 100 through the inlet 110. Due to the tangential arrangement of the inlet 110, the airflow is forced to follow a helical path around the interior of the wall 104. Larger dirt and dust particles are separated by cyclonic motion around the wall 104. These particles are then collected at the base 116 of the cyclone 102. Separation of larger particles will occur in the region of the cyclone 102 surrounded by the first portion 106 of the wall 104 and also the portion of the cyclone 102 surrounded by the lip 114. Separated particles gather in the portion of the cyclone 102 surrounded by the second portion 108 of the wall 104.

The partially-cleaned airflow then flows back up the interior of the cyclone 102 and exits the cyclone 102 via the through-holes in the shroud 121. Once the airflow has passed through the shroud 121, it enters the outlet 124 and from there is divided between the tangential inlets 132 of each of the further cyclones 130. Each of the further cyclones 130 has a diameter smaller than that of the cyclone 102. Therefore, the further cyclones 130 are able to separate smaller particles of dirt and dust from the partially-cleaned airflow than the cyclone 102. Separated dirt and dust exits the further cyclones 130 via the cone openings 136. Thereafter, the separated dirt and dust passes down the passageway 138 and into the collector 142. The separated dirt and dust eventually settles at the base of the collector 142.

Cleaned air then flows back up the further cyclones 130, exits the further cyclones 130 through the air outlets 134 and enters the duct 150. The cleaned air then passes from the duct 150 sequentially through the pre-motor filter 152, the motor and fan unit, and a post-motor filter before being exhausted from the vacuum cleaner 10 through the air vents 24.

It is likely that, in use, the hand-held vacuum cleaner 10 will be held in a variety of orientations. It may even be held upside down in use. When the cyclonic separating apparatus 100 is tilted away from the vertical, a large proportion of the separated dirt and dust that may otherwise move towards the inlet 110 and the shroud 121 is caught in an annular pocket created between the lip 114 and the second portion 108 of the wall 104. Further, the presence of the above-described pocket may assist in the creation of stagnation points and eddy-currents within the lower portion of the cyclone 102. This may further prevent re-entrainment of separated dirt and dust into the return airflow.

Regarding the collector 142, a pocket is created between the second portion 146 of the collector 142 and the further lip 148. The pocket will prevent a proportion of the separated dirt and dust which may potentially block the cone openings 136 or other parts of the further cyclones 130 from re-entering the passageway 138 when the hand-held vacuum cleaner 10 is tilted away from the vertical.

The cyclone 102 and collector 142 can be emptied simultaneously by releasing the catch 120 to allow the base 116 to pivot about the hinge 118 so that the separated dirt and dust can fall away from the cyclonic separating apparatus 100.

Both the lip 114 and the further lip 148 may take different configurations or shapes from those shown in the first embodiment. FIGS. 4 to 11 illustrate schematically eight further alternative configurations of the lip or lips which fall within the scope of the invention. In these illustrations, all detail will be omitted other than the general shape of the lip and adjoining wall portions. These configurations of lip may be applied to either the lip in the cyclone or to the further lip in the collector.

FIG. 4 shows a second embodiment of the invention. In this embodiment, the cyclonic separating apparatus 200 includes a lip 202 which extends from a first portion 204 of a wall into a region surrounded by a second portion 206 of the wall. The lip 202 has a plurality of through-holes which allow air to pass but block larger particles of dirt and dust. Otherwise, the lip 202 is the same as the lip 114 described above.

FIG. 5 shows a third embodiment of the invention. In this embodiment, the cyclonic separating apparatus 250 includes a lip 252 which extends from a frustoconically-shaped first portion 254 of a wall into a region surrounded by a second portion 256 of the wall. The second portion 254 of the wall is partly frustoconical-shaped and partly cylindrical.

FIG. 6 shows a fourth embodiment of the invention. In this embodiment (which is not shown to scale), the cyclonic separating apparatus 300 has a longitudinal axis X′-X′ and includes a lip 302 which extends from a cylindrically-shaped first portion 304 of a wall into a region surrounded by a second portion 306 of the wall. The lip 302 extends inwardly from the first portion 304 of the wall at an angle to the longitudinal axis X′-X′.

FIG. 7 shows a fifth embodiment of the invention. In this embodiment (which is also not shown to scale), the cyclonic separating apparatus 350 has a longitudinal axis X″-X″ and includes a lip 352 which extends from a cylindrically-shaped first portion 354 of a wall into a region surrounded by a second portion 356 of the wall. The lip 352 extends outwardly from the first portion 304 of the wall at an angle to the longitudinal axis X″-X″.

FIG. 8 shows a sixth embodiment of the invention. In this embodiment, the cyclonic separating apparatus 400 includes a lip 402 which extends from a cylindrically-shaped first portion 404 of a wall into a region surrounded by a second portion 406 of the wall. The lip 402 comprises two parts—a first part which forms a substantially straight extension of the first portion 404 of the wall and a second part which forms an inwardly-extending annular part at right angles to the first part.

FIG. 9 shows a seventh embodiment of the invention. In this embodiment, the cyclonic separating apparatus 450 includes a lip 452 and first and second portions 454, 456 of a wall. This embodiment is the same as the sixth embodiment except that the annular part extends outwardly.

FIG. 10 shows an eighth embodiment of the invention. In this embodiment, the cyclonic separating apparatus 500 includes a lip 502 extending from a cylindrically-shaped first portion 504 of a wall into a region surrounded by a second portion 506 of the wall. The lip 502 comprises two parts—a first part which extends inwardly and a second part which extends parallel to the first portion 504 of the wall.

FIG. 11 shows a ninth embodiment of the invention. In this embodiment, the cyclonic separating apparatus 550 includes a first portion 552 of a wall which has a cylindrical part and an annular part. A lip 554 extends from the annular part of the first portion 552 into a region surrounded by a second portion 556 of the wall.

The arrangements illustrated in FIGS. 4 to 11 are intended to show that the number, shape and configuration of the lip or lips can be varied. It will be understood that other arrangements are also possible. For example, the further cyclone assembly may comprise any number of cyclones. Alternatively, the further cyclone assembly need not be present and a filter or other separating media may take its place.

There need not be a collector or a lip on the collector. What is important is that there is one cyclone which has a wall with two portions of different sizes, and a lip extends from the smaller portion into the larger portion.

The lips in the above-described embodiments all extend around the whole of the circumference of the wall of the cyclone. However, this need not be so. The lip may extend around only part of the circumference of the wall of the cyclone. Alternatively, a plurality of lips may be provided, each of which extends partly around the circumference of the wall of the cyclone.

The lip may extend into a small part of the region surrounded by second portion of the wall of the cyclone or, alternatively, the lip may extend further into the cyclone. Any number of lips may be provided; for example, several concentric lips may be provided.

Claims

1. A cyclonic separating apparatus for separating particles from a dirt- and dust-laden airflow comprising a cyclone for separating and collecting dirt and dust from the dirt- and dust-laden airflow, the cyclone having an air inlet, an air outlet, a longitudinal axis and a wall upon which cyclonic separation takes place, the wall comprising a first portion and a second portion spaced further from the longitudinal axis than the first portion, the first and second portions being axially spaced along the longitudinal axis,

wherein the cyclone further comprises at least one lip extending from the first portion of the wall into a portion of the cyclone surrounded by the second portion of the wall.

2. The cyclonic separating apparatus of claim 1, wherein the first portion of the wall is cylindrical and has a first radius.

3. The cyclonic separating apparatus of claim 2, wherein at least a part of the second portion of the wall is cylindrical and has a second radius.

4. The cyclonic separating apparatus of claim 1, 2 or 3, wherein the first portion of the wall is located between the air inlet and the second portion of the wall.

5. The cyclonic separating apparatus of claim 1, 2 or 3, wherein the at least one lip has a plurality of holes therethrough.

6. The cyclonic separating apparatus of claim 1, 2 or 3, wherein the at least one lip forms a substantially straight extension of the first portion of the wall.

7. The cyclonic separating apparatus of claim 1, 2 or 3, wherein a distal end of the at least one lip is spaced at a distance from the longitudinal axis greater than that of the first portion.

8. The cyclonic separating apparatus of claim 1, 2 or 3, wherein a distal end of the at least one lip is spaced at a distance from the longitudinal axis less than that of the first portion.

9. The cyclonic separating apparatus of claim 7, wherein the at least one lip extends from the first portion of the wall at an angle to the longitudinal axis.

10. The cyclonic separating apparatus of claim 1, 2 or 3, wherein a single lip is provided, the lip extending around the circumference of the wall.

11. The cyclonic separating apparatus of claim 1, 2 or 3, further comprising at least one further cyclone and a collector which are located downstream of the air outlet, the at least one further cyclone being arranged to deposit separated dirt and dust into the collector.

12. The cyclonic separating apparatus of claim 11, wherein the collector has a longitudinal axis, a wall and at least one further lip extending from the said wall into the collector.

13. The cyclonic separating apparatus of claim 12, wherein the further cyclone has an inlet and a cone opening and the at least one further lip extends away from the cone opening of the at least one further cyclone.

14. The cyclonic separating apparatus of claim 12, wherein at least a part of the at least one further lip is parallel to a part of the wall of the collector.

15. (canceled)

16. A vacuum cleaner comprising the cyclonic separating apparatus of claim 1, 2 or 3.

17. The vacuum cleaner of claim 16, wherein the vacuum cleaner is a hand-held vacuum cleaner.