EP2375953B1

EP2375953B1 - Dust receptacle for a vacuum cleaner

Info

Publication number: EP2375953B1
Application number: EP09803893.8A
Authority: EP
Inventors: Richard Waters; Philip Grove
Original assignee: Techtronic Floor Care Technology Ltd
Current assignee: Techtronic Floor Care Technology Ltd
Priority date: 2008-12-23
Filing date: 2009-12-23
Publication date: 2015-06-03
Anticipated expiration: 2029-12-23
Also published as: GB2466625A; AU2009332757A1; RU2553199C2; CN102300493B; RU2011129396A; EP2375953A1; GB0823442D0; GB2466625B; CN102300493A; WO2010073046A1

Description

This invention relates generally to the field of suction cleaners (which are commonly, and will herein be, referred to as vacuum cleaners), and more particularly to a dust receptacle for a vacuum cleaner.
Vacuum cleaners typically include a suction nozzle with which dirt, dust and the like is sucked into the cleaner, and a body containing a motor and an impeller, by which a suction force is generated. The dust-laden air flows from the nozzle to the body, wherein the dust is separated from the air by some means, such as by a swirling motion in a cyclone unit, and/or by a porous filter through which the dust particles cannot pass. The separated dust is retained in a collecting part of the separator arrangement, and may later be disposed of.
In referring herein to dust, it is to be understood that what is sucked up and entrained in the air stream created by the vacuum cleaner can include particles of a very wide range of sizes, ranging from microns to millimetres or even centimetres. Fibres, including animal and human hair, and scraps of fabric, paper, plastics, etc. are also likely to be sucked up. All such things are to be understood as included within the term "dust" used herein, and whatever system is utilised for dust separation and collection in a vacuum cleaner ought to be able to cope with all of them.
A problem arising with such systems is that the low density of the dust particles means that a relatively large volume is occupied by the dust collected in the collecting part of the cleaner. This is particularly the case where the dust includes fibres and fluff. In cyclonic separator arrangements, a large amount of space is required by the one or more cyclones, and so less space is available to store separated dust. The less dust storage space is provided, the more often the user must empty the collected dust from the vacuum cleaner.
In addition to the problems mentioned above, the process of emptying dust from the vacuum cleaner commonly results in loosely stored dust particles becoming airborne. This makes cleaning the components more difficult, and to some extent negates the removal of dust from the environment in the first instance. Additionally, the increase in airborne dust particles may affect people suffering with conditions such as asthma.
Arrangements have been proposed for compacting collected dust in a vacuum cleaner, so that it occupies less space. EP 1671570 discloses a dust collecting unit for a vacuum cleaner in which a dust collection container of a vacuum cleaner has a plate dividing the container into a upper separating compartment and a lower storage compartment for dust, the plate being supported by a piston and cylinder unit connectable to the negative pressure generated by the motor and fan of the vacuum cleaner. This causes the piston and cylinder unit to be contracted, to cause the plate to compress dust in the storage parts of the container.
JP 2003038396A discloses an arrangement in which a bellows is disposed in a cyclonic separator chamber, arranged to be contracted when the interior of the cyclone is subject to low pressure in operation. When not in operation, the interior of the bellows is subject to atmospheric pressure and the bellows expands to compress dust in the chamber. US 4363156 discloses a vacuum cleaner dust container with a bellows whose interior can be subject to the positive pressure created by the motor and fan of the cleaner to expand the bellows and compress the dust in a dust-collecting bag.
EP1987757 discloses a dust separator that discharges dust into a dust collecting chamber having a dust pressing plate reciprocated by a motor.
According to one aspect of the present invention, we provide a dust receptacle for a vacuum cleaner according to the subject-matter of claim 1.
The higher pressure of air in the interior of the extendible element may be established by the admission of air at atmospheric pressure to its interior. Typically, in a vacuum cleaner, the parts of the air flow path therein upstream of the motor-driven fan which creates the suction air flow of the vacuum cleaner are predominately at a slightly sub-atmospheric pressure because of the resistance to the air flow presented by the passages and dust separators (whether of cyclonic type or filtration type) upstream of the fan. Because of its connection to the separator to receive dust therefrom, the dust collection chamber can be expected to have such a sub-atmospheric pressure in its interior when the cleaner is operating.
Alternatively, the air at higher pressure may be derived from the exhaust of the fan which creates the suction air flow of the vacuum cleaner. Most vacuum cleaners have an exhaust filter following the fan, as a final safeguard against the emission of any dust particles which might somehow avoid the dust separator(s) of the cleaner and to trap any particles such as the dust created by the brush gear of an electric motor which drives the fan. Upstream of such an exhaust filter, the air pressure can be expected to be slightly above atmospheric pressure.
A valve is provided for admitting the higher pressure air to the interior of the extendible element, at intervals as required. Such a valve may be caused to open at pre-determined time intervals, for example under the control of an electrical timer by means of an operating device such as a solenoid, electric motor, or other means.
Alternatively, the valve may be caused to open for a certain time whenever the extendible element is at or near its fully-contracted state.
A bleed aperture provides for controlled equalisation of pressure between the interior and exterior of the extendible element.
The extendible element may be of bellows configuration, incorporating elements of flexible material to enable the extendible element to extend and contract lengthwise.
Conveniently, the extendible element may be constituted by a length of suction hose of the type commonly used in vacuum cleaners, which is able to be extended when subject to lengthwise tension but which contracts when no such tension is applied. Such a hose typically comprises a resilient helical element, for example of metal wire, on which a flexible material, e.g. a suitable plastics material, is supported. The resilience of the helical element is arranged to contract the hose.
The pressing member may comprise a plate moveable within the dust collection chamber. The pressing member may comprise apertures extending between its opposite surfaces, to enable large dust particles to pass therethrough.
According to another aspect of the invention, we provide a dust separator and collector device for a vacuum cleaner, comprising a dust receptacle as above set forth and a dust separator having a dust outlet arranged to discharge separated dust into the inlet of the dust collection chamber.
Preferably the dust separator comprises at least one cyclone.
The cyclone may be of the type in which dust is discharged laterally of a separating chamber in which cyclonic air flow takes place, i.e. transversely, e.g. tangentially, of the axis about which the cyclonic air flow takes place.
The dust separator-collector may be a primary dust separator-collector for a vacuum cleaner, air from the primary separator-collector being delivered to one or more further separator-collectors, before reaching the fan of the cleaner. Such a further separator-collector may comprise one or more further cyclonic separators (which may be of smaller size than the primary cyclone(s), to separate smaller dust particles which might not be separated by the primary cyclone(s) and/or one or more filters.
According to another aspect of the invention, we provide a vacuum cleaner having a dust separator-collector according to the second aspect of the invention.
These and other features of the invention, and the advantages thereof, will now be described by way of example with reference to the accompanying drawings of which:

Figure 1 is a side cross-section of a dust receptacle in connection with a dust separation chamber.
Figure 2 is a plan view of the arrangement shown in Figure 1, showing a secondary cyclonic separator alongside the figure 1 arrangement.
Figure 3 is a diagrammatic perspective view of part of the duct receptacle of figure 1.
Figure 4 is a side elevation of a vacuum cleaner including a dust receptacle in accordance with the invention.

Referring firstly to figures 1 and 3 of the drawings, a dust receptacle 10 for a vacuum cleaner comprises a dust collection chamber indicated generally at 14, alongside a dust separation chamber 12. The dust collection chamber 14 has an upper part 38 and a lower part 39, the lower part having a bottom wall 18 from which a circular peripheral wall 20 extends upwardly towards the upper part 38 of the chamber. As illustrated, the peripheral wall 20 tapers slightly from its bottom end to its top end, but it could be cylindrical. In the upper part 38 of the dust collection chamber 14 is a dust inlet 16 which connects the dust collection chamber to the dust separation chamber 12.
The dust separation chamber 12 is a cyclonic chamber having a tangential inlet 48 for airflow with dust entrained in it, the tangential orientation of the inlet 48 causing air to swirl within the chamber 12 about an upright central axis thereof, so that dust is separated from the air and is expelled transversely from the chamber through a tangential exit passage 13 leading to the inlet 16. Air from which the dust has been separated leaves the chamber by way of an exit 42 at the top of the chamber 12 on the central axis thereof.
At the upper end of the peripheral wall 20 of the chamber 14, spaced a short distance above the dust inlet 16, is a radially inwardly extending annular wall 36. Above the wall 36 there is a wall portion 37 which as illustrated is frustoconical and another annular wall followed by an upwardly extending slightly tapering wall forming a housing part 46. At the top of the receptacle, there is a top wall 32 closing off the top of the housing part 46. The dust collection chamber 14 is provided with a pressing apparatus, including a hollow extendible element 30 and a pressing member 22. The pressing member 22 is circular in configuration and has an upper surface 26 and lower surface 24, with a connection portion 28 extending upwardly from the centre of its upper surface 26. The pressing member 22 is movable upwardly and downwardly within the chamber 14 between an upper limiting position and a lower limiting position. In the upper limiting position (shown in full lines in figure 1), the upper surface 26 of the pressing member contacts the annular wall portion 36, whilst in the lower limiting position (shown in broken lines) the lower surface 24 of the pressing member contacts the bottom wall 18. In the upper limiting position, the pressing member 22 fits closely within the circumferential wall 20 of the chamber, whilst in the lower limiting position it is spaced by a small distance from the circumferential wall 20, in consequence of the slight upward taper of the wall 20.
The pressing apparatus further comprises a hollow extendible element 30 which is connected between the connection portion 28 of the pressing member and a connection fitting on the top wall 32 of the chamber. The extendible element is contracted when the pressing member is in its uppermost limiting position and extended as shown in broken lines in figure 1 when the pressing member is in its lower limiting position. The extendible element 30 is resilient so that when it is not subjected to any external forces it contracts to pull the pressing member 22 to its uppermost position. The extendible element is generally of bellows configuration, and conveniently may be constituted by a portion of extendible suction hose such as are well known for use on vacuum cleaners: such a hose typically comprises a flexible plastics material supported on a helical resilient wire element so that normally it is in the contracted condition but is able to extend when subjected to lengthwise tension.
The pressing member 26 is a circular plate-like element, and has a number of apertures 27 extending between its upper surface 26 and lower surface 24. The apertures in the member allow dust and debris to pass through the element when, as described below, the pressing member is at a position within the collection chamber beneath the dust inlet 16. Thus dust may rest in the lower part 39 of the chamber, on the lower wall 18. For emptying the chamber, lower wall 18 may be openable e.g. by pivoting relative to the wall 20 of the chamber.
The apertures in the pressing member may be of any suitable shape and size, but must provide for particles of dust as large as the vacuum cleaner is capable of handling to pass through the pressing member to reach the lowermost part of the chamber. Disposed on the top wall 32 of the chamber is a device by which the interior of the extendible element 30 can be connected to the external atmosphere, and hence be at atmospheric pressure. This may comprise a valve 40 operable to open and close an aperture in the top wall 32. When the vacuum cleaner is operating, because of the air flow drawn through the separating chamber 12 by the source of suction of the cleaner, the air pressure within the dust collection chamber 14 will typically be some 10 to 20 kilopascals below atmospheric pressure, and possibly a greater difference in pressure may be created if there is any blockage of the inlet to the cleaner. The exterior of the extendible element 30 is, of course, subject to the sub-atmospheric pressure in the chamber 14 when the vacuum cleaner is operating.
The extendible element 30 is of impermeable material, but a small bleed aperture is provided to enable air to pass at a predetermined rate between its interior and exterior. The bleed aperture may be provided in the wall of the extendible element, or possibly in the connection portion 28 of the pressing member 22. When air passes between the interior and exterior of the extendible element, any differential in pressure between the two is reduced, in the absence of any other influences.
The valve 40 may take various forms. It may be operated to open and allow air at atmospheric pressure into the interior of the extendible element 30 by a member provided on the pressing member 22, so that the valve is opened when the pressing member is at or very near its uppermost position and be closed when the pressing member has moved a predetermined distance downwardly from its uppermost position. For example, an elongate rod may be provided inside the extendible element 30, connected so as to extend upwardly from the connecting part 28 of the pressing member. Such an elongate rod may engage a flap valve to push it open when the pressing member is at its highest point. Closure of the flap valve element after the pressing element has moved downwardly from its uppermost position may be damped, so that after the pressing member has descended until the elongate rod is disengaged from the valve element, the valve element remains open for a short additional time, e.g. about 0.3 seconds.
When the vacuum cleaner starts to operate with the pressing member in its uppermost position, when a sub-atmospheric pressure is established in the chamber 14 while the interior of the extendible element is at atmospheric pressure, the pressing member begins to descend. When the pressing member has descended to the point at which the valve element has closed, the interior pressure of the extendible element will begin to equalise with the pressure in the collecting chamber by way of the bleed aperture above described. The pressing member will continue to descend until the force exerted as a result of the reduced pressure difference is balanced by the tension in the extendible element. When the pressures have equalised, the pressing member will be raised by virtue of the tension force exerted by the extendible element when it is extended. As long as the vacuum cleaner continues to operate, the pressing member will be successively lowered then raised causing the dust beneath it to become compacted to some extent. As above mentioned, there are apertures in the pressing member 22 so that dust can fall through the pressing member in the chamber 14. Since the pressing member is not guided accurately within the collecting chamber, each time it reaches the lowermost point of its travel within the collection chamber it is likely to do so in a slightly different orientation, so the effect will be a degree of compaction of all the dust at the bottom part of the chamber.
Instead of a valve operated mechanically in response to the position of the pressing member, it may alternatively be operated by a solenoid mechanism, e.g. controlled by a timer or otherwise. Alternatively a valve e.g. a rotary valve could be operated on a timed basis by an electric motor or the like,.
The rate at which the pressing member descends is determined by the cross sectional area of the extendible element and the difference in pressure between its interior and exterior. The speed at which it returns to the top of the collecting chamber will depend on the rate at which air bleeds out of the bleed aperture associated with the extendible element and hence the rate at which the pressure differential between its interior and exterior decreases.
If large items of debris fall into the dust collection chamber 14 and become lodged below the pressing member 22, this may prevent the lower surface 24 of the pressing member 22 from contacting the dust as effectively as it would otherwise do. However, in the embodiment above described, the pressing member is not fixed in a horizontal position and may tilt within the chamber so that it is still effective in compacting, to some extent, the collected dust.
It may, in some cases, be preferable for the pressing member to be stabilised so that it remains in an approximately horizontal orientation throughout its upwards and downwards movement within the collecting chamber. A guide or guides for this purpose may be provided. For example, the pressing member may be provided with a number of spaced guide formations which extend upwardly and/or downwardly from its periphery, to maintain its orientation by contact with the peripheral wall of the chamber. Alternatively, the pressing member may be provided with a peripheral skirt formation, extending upwardly and/or downwardly from the pressing member to contact the peripheral wall of the chamber if the pressing member tilts significantly from the horizontal.
In yet a further alternative, one or more upright guide formations may be provided within the peripheral wall of the chamber, engaging corresponding formations in the pressing member for guiding the latter. Yet further, a cylindrical guide may be provided centrally in the dust collection chamber, extending up from positions at or adjacent the uppermost and lowermost limits of movement of the pressing member within the chamber. Such a guide may be of smaller diameter than the inside diameter of the extendible element, so that as the pressing member descends the extendible element receives the guide within its interior. The pressing member may have a formation which engages the guide sufficiently closely to control the orientation of the pressing member.
As an alternative to a bellows-type extendible element, conveniently provided by a length of extendible suction hose, it would be within the scope of the invention for the element to comprise a telescopically-extendible assembly of hollow portions slidable lengthwise of one another, or a piston and cylinder device or devices.
Although, as described, a cyclonic separator of the "throw-off" (lateral discharge of separated dust) type is disposed alongside the dust collection chamber, other types of separator may be utilised in the invention. Figure 2 shows in plan view the disposition of the cyclonic dust separation chamber 12 alongside the dust collection chamber 14, together with the disposition of the inlet 48 to the separation chamber 12 and the dust exit passage 13 leading to the collection chamber 12. The air exit 42 from the separation chamber may extend, by means of suitable ductwork not shown, to a secondary cyclonic separator and collector assembly indicated generally at 50. This secondary cyclonic dust separation and collection unit 50 may comprise a plurality of individual secondary cyclones 52, connected in parallel with one another to the exit 42 of the separator 12 so that the total airflow is shared between them. The individual secondary cyclones 52 are each of relatively small diameter, so that they are capable of removing much smaller particles from the air flow than can be removed by the cyclonic separator 12, so that substantially all dust particles are effectively removed from the air flow by the successive effects of the separators 12, 50. The cyclones 52 may be of the type having a frustoconical cyclonic chamber, with separated dust emerging from the smaller-diameter lower ends of the cyclones to be collected in a further dust collection chamber beneath the cyclones.
Air from which further dust particle separation has been effected by the secondary cyclones 52 is led, again by appropriate passages and ductwork, and possibly a pre-motor filter element, to a motor and fan which create the suction airflow of the vacuum cleaner. Thence, clean air may be expelled the ambient atmosphere, possibly by way of an exhaust filter to remove any fine dust particles which may have escaped removal by the previous separation stages, and also to trap any debris emitted by the fan motor.
The invention is applicable to the dust separators and collectors of vacuum cleaners of both the cylinder type and the upright type. The exact disposition of the dust separation and collection chambers 12, 14 relative to one another may be chosen to suit the particular machine in which they are to be used and arranged to suit the styling as well as the technical characteristics of such a machine. Similarly, any suitable disposition of the secondary dust separator and collector unit relative to a primary unit may be arranged to suit the particular machine. For example, a cleaner of the upright type more readily accommodates a relatively tall but narrow dust separator and collector assembly than does a cleaner of the cylinder type: hence an arrangement of a secondary cyclonic separator-collector assembly alongside a primary separator and collector assembly, as shown in figure 2, may be more readily accommodated in a cleaner of the cylinder type, although it could be accommodated in either type of cleaner.
Figure 4 illustrates in side elevation a vacuum cleaner of the upright type, having a cleaning head 60 moveable over a ground surface to be cleaned on wheels 62, with a suction opening 64 at the front end of the head 60 relative to the wheels 62. A dust separation-collection assembly is indicated at 66, with a lower part of a dust collection chamber as 14 indicated at 68. Individual cyclones 52 of a secondary cyclonic separator-collector assembly 70 are indicated as being disposed at a relatively high level compared with the collection chamber 68: for example they may be disposed alongside or around part of the periphery of an uppermost part of the primary dust collection chamber 68, and may discharge any dust which they separate from the airflow through them into a collection chamber disposed in an uppermost part of the separator-collector unit. Many possible arrangements of primary and secondary cyclonic separation and collection assemblies have been proposed for use in vacuum cleaners, and the invention is, in principle, applicable to many of them.
The invention is applicable to vacuum cleaners of both the "upright" type and the "cylinder" or "canister" type
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.
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.

Claims

A dust receptacle (10) for a vacuum cleaner, the receptacle including:
a dust collection chamber (14) having an inlet (16) for dust, the dust inlet being in communication with an air flow to a source of suction; and
a pressing member (22) moveable within the chamber for contacting dust therein;
a hollow extendible element (30) operable on the pressing member to move same within the chamber, the extendible element having an interior and an exterior, and being operable to extend in response to the establishment in the interior of a higher air pressure that is higher than a chamber air pressure within the chamber and to which its exterior is subject, and to contract when the interior is not subject to the higher air pressure,
a valve (40) for admitting air with the higher air pressure to the interior of the extendible element at intervals, and
a bleed opening for equalisation of air pressure between the interior and the exterior of the extendible element,

wherein the dust receptacle is configured such that the interior of the extendible element is subject to the higher air pressure at intervals, which higher air pressure is then relieved, to cause successive extension and contraction of the extendible element while the cleaner is operating.
A dust receptacle according to claim 1, wherein the higher air pressure in the interior of the extendible element is established by the admission of air at at least atmospheric pressure to the interior of the extendible element.
A dust receptacle according to claim 1 or claim 2, wherein the valve (40) is caused to open at pre-determined time intervals.
A dust receptacle according to claim 3, wherein the valve (40) is caused to open for a predetermined time whenever the extendible element is at or near its fully-contracted state.
A dust receptacle according to any one of the preceding claims, wherein the extendible element (30) is of bellows configuration.
A dust receptacle according to claim 5, wherein the extendible element is of flexible material supported on a helical resilient element.
A dust receptacle according to any one of the preceding claims, wherein the pressing member (22) is able to change its orientation within the dust collection chamber.
A dust receptacle according to any one of claims 1 to 6, wherein the pressing member (22) is guided to remain in a generally constant orientation within the dust collection chamber.
A dust receptacle according to any one of the preceding claims, wherein the pressing member (22) is a circular plate-like element and has a number of apertures (27) extending between its upper and lower surfaces (26, 24).
A dust separator and collector device for a vacuum cleaner, comprising a dust receptacle according to any one of the preceding claims, together with a dust separator having a dust outlet arranged to discharge separated dust into the inlet of the dust collection chamber.
A dust separator and collector device according to claim 10, wherein the dust separator comprises at least one cyclone.
A dust separator and collector device according to claim 11 wherein the or each cyclone is of the type in which dust is discharged laterally of a separating chamber in which cyclonic airflow takes place.
A dust separator and collector device according to any one of claims 10 to 12, which is a primary dust separator and collector device for a vacuum cleaner, wherein the primary dust separator and collector device is configured such that air from the primary dust separator and collector device is delivered to one or more further dust separator and collector device.
A dust separator and collector device according to claim 13 in combination with a further dust separator and collector device, the further dust separator and collector device arranged to receive air discharged from the primary dust separator and collector device comprises one or more further cyclonic separators and/or one or more filters.
A vacuum cleaner having a dust receptacle according to any one of claims 1 to 9 or a dust separator and collector device according to any one of claims 10 to 14.