Vacuum Cleaning System

Handheld vacuum cleaners and ‘stick vacs’ are popular household machines as they are lightweight and manoeuvrable compared to larger mains-connected cylinder and upright cleaners. The useful portability is usually achieved at least in part by being battery-powered, and many such machines now are bagless for convenience such that the collected dirt is stored in an integral dirt bin. Typically, handheld machines are used for frequent spot cleaning tasks but, as battery technology improves, the trend is towards longer cleaning operations. The trend for handheld vacuum cleaners to be the cleaner of choice for many households means that some users may prefer a larger dirt bin so that the cleaner can hold more dirt and debris between bin empties. However, the more compact size of battery-powered vacuum cleaners means that users have to perform regular maintenance such as bin emptying to keep them performing optimally. In addition to bin emptying, users are also required to carry out filter cleaning tasks occasionally in order to clean the fine air filters that such machines usually include to filter the discharged airflow. Such filters may meet HEPA standards of filtration so they need cleaning periodically to maintain their performance. Filter cleaning usually involves the user washing the filter in water and then leaving the filter to dry over an extended period, usuallyhours or more during which time the vacuum cleaner cannot be used. It is desirable to be able to extend the life of such filters without requiring the user to wash them.

In a first aspect, examples of the invention provide a vacuum cleaning system comprising a vacuum cleaner having a vacuum motor, a dirt bin, a primary separation system, a membrane filter, and an air valve arrangement configured to control air flow through at least the membrane filter. The vacuum cleaner is configured to be operable in a surface cleaning mode of operation and a self-cleaning mode of operation. In the surface cleaning mode of operation, the vacuum cleaner is configured such that the vacuum motor draws dirty air from a dirty-air inlet through the dirt bin, the primary separation system and the membrane filter in a first airflow direction, and, in the self-cleaning mode of operation, the vacuum cleaner is configured to permit air to flow from the air valve arrangement through the membrane filter in a second airflow direction to clean dirt from the membrane filter.

Usefully, therefore, airflow can be routed through the vacuum cleaner in a second direction to clean the caked on dirt from the membrane filter. The membrane filter may be used as a pre-motor filter positioned upstream from the vacuum motor, or as a post-motor filter, positioned downstream from the vacuum motor, when considered in an airflow direction during a surface cleaning mode of operation.

In addition to the air valve arrangement permitting air to flow through the membrane filter in the self-cleaning mode of operation, it may be further configured to cause air to flow across a surface of the membrane filter during the self-cleaning mode. Here, air flow across the surface of the membrane filter means that the air flows substantially parallel to the surface. By configuring the air valve arrangement to cause air to flow through the membrane filter, but also across the surface of the membrane filter during a self-cleaning mode of operation, the cleaning effect of the membrane filter is enhanced.

In some examples, the membrane filter is movably mounted within the vacuum cleaner, wherein said movement assists in dislodging dirt from the membrane filter. During this movement, the membrane filter is movable from a first position to a second position when the vacuum cleaner enters the self-cleaning mode of operation to assist in dislodging dirt from the membrane filter. The movement of the membrane filter may be combined with an impact from an impactor that is configured to provide a mechanical impact pulse to the membrane filter. This provides a further improvement to the cleaning of the filter during the self-cleaning mode of operation.

Movement of the membrane filter may be triggered by various events. In one example, movement of the membrane filter from the first position to the second position is caused by operation of the air valve arrangement. In another example, movement of the membrane filter from the first position to the second position is caused by opening of the dirt bin door. In either example, a mechanical or electronic triggering mechanism may trigger the movement of the membrane filter. Such movement may be powered by any suitable means, such as airflow through the membrane filter, or by way of a spring-loaded mechanism.

Although the reverse flow (in the second direction) of air through the membrane filter may be generated by the vacuum cleaner itself, in other examples of the invention, the vacuum cleaning system further comprises a docking station, wherein the docking station comprises a dirt storage chamber and an interface configured to mate with a dirt bin of the vacuum cleaner such that dirt expelled from the dirt bin through a bin opening is ejected into the dirt storage chamber of the docking station. In the self-cleaning mode of operation, the system is configured to: operate the vacuum generator to generate a partial vacuum in the dirt storage chamber and, once a sufficient negative pressure level has been generated, operating the air valve arrangement to cause a pulse of air to flow from the air valve arrangement through the membrane filter in the second airflow direction. In addition, the air valve arrangement may be adapted so that when it is operated when a sufficient negative pressure level has been generated, the air valve arrangement causes a pulse of air to flow into the dirt bin of the vacuum cleaner thereby to eject dirt from the dirt bin through the bin opening and into the dirt storage chamber.

The vacuum motor of the vacuum cleaner is used to discharge the dirt and dust in the vacuum cleaner into the dirt storage chamber of the docking station, which avoids the need for a further vacuum motor to be provided in the docking station. This reduces the energy usage for the bin emptying operation which improves system efficiency. The air pulsation function causes a high speed airflow through the bin to ensure that the dirt bin is emptied effectively and that dirt stuck to surfaces within the vacuum cleaner is removed during the emptying process.

Preferably the dirt bin is associated with a centrifugal or cyclonic separator which is adapted to cause a circulating flow of air which separates entrained dirt from the airflow. In this context, in one example the air valve arrangement is configured to generate a swirling air flow through the dirt bin. A swirling, or rotational, flow of air improves the efficiency with which the dirt is emptied from the bin compared to a flow of air that is directed generally axially through the dirt bin. Further, this type of airflow guards again dust getting stuck in localised patches inside the dirt bin.

The air valve arrangement may be operated by different methods. In one approach, the air valve arrangement may be electronically controlled and, as such, may be configured to communicate with a control system of the vacuum cleaner which commands the air valve arrangement to open and close intermittently in order to achieve the required one or more pulses of air. The time intervals which govern the opening and closing of the air valve arrangement may be set at a predetermined time period. Alternatively, the time intervals may be governed by the control system sensing the pressure within the dirt storage chamber of the docking chamber and actuating the air valve arrangement when a sufficient negative pressure has been detected. However, in another example the air valve arrangement is configured to be operated by differential pressure between the dirt bin and ambient environment.

Although a single pulse of high velocity air through the dirt bin of the vacuum cleaner may be sufficient to clear the membrane filter of dust, and, optionally, eject much of the dust, dirt and debris, preferably the air valve arrangement is configured to be operated repeatedly during sustained operation of the vacuum generator, thereby permitting a plurality of sequential air pulses to flow through the dirt bin. This is envisaged to a more thorough cleaning of the membrane filter of the vacuum cleaner, and a more effective ejection of dirt from the dirt bin. It should also be appreciated at this point that during the self-cleaning mode of operation, the airflow through the membrane filter may flow in the reverse direction, but also in the first airflow direction, for example as part of a pulsed operation to help dislodge dirt/caking from the membrane filter.

The dirt storage chamber may include a first chamber portion and a second chamber portion separated by a one way valve. Beneficially, this allows dirt to pass into the second chamber portion which is then trapped in that location by the valve. This reduces the tendency of dust to blow back out of the docking station, particularly when the vacuum cleaner is disengaged from it.

The second chamber portion of the dirt storage chamber may be removable or have a removable portion such as a bin, bucket or receptacle which allows the dirt stored therein to be removed. One option is for a removable air-permeable dirt bag to be provide in the second chamber portion which operates like a conventional vacuum cleaner bag. A user can therefore simply remove the bag when the docking station needs to be emptied. Since the docking station does not need to be portable, the bag can be made much larger than a typical vacuum cleaner bag so that it needs to be emptied less frequently, thereby providing particular convenience for the user.

In one example, the dirt storage chamber may include one or more air flow apertures to allow air to flow into it during the dirt bin emptying mode. This provides a flow of clean air to enter the dirt storage chamber during a bin emptying cycle which suppresses dirt blow back. Conveniently, the one or more air flow apertures are located in the first chamber portion.

In order to improve the cleaning effectiveness of the airflow in the dirt storage chamber, the one or more air flow apertures are configured to generate a swirling air flow around the dirt storage chamber.

The vacuum generator may create a negative pressure level in the dirt storage chamber by drawing air from the dirt storage chamber through the vacuum cleaner itself, as it would do during a normal vacuum cleaning operation. The system is envisaged to work particularly well with a vacuum cleaner which features a vacuum nozzle i.e. the suction inlet to the vacuum cleaner, which is at least in part surrounded by the bin door. This means that the bin door is engaged with the docking station and the vacuum nozzle accesses the interior of the dirt storage chamber for evacuating the air therefrom. Other configurations could however be acceptable. In such a situation, the interface between the vacuum cleaner and the docking station may be reconfigurable to enable it to mate, selectably, with a second vacuum cleaner. The docking station could then be used with different vacuum cleaning machines that are owned by the same user.

Features described above in connection with the first aspect of the invention are equally applicable to other aspects of the invention, and vice versa.

Examples of the invention relate to a vacuum cleaning system including a vacuum cleaner which can in some examples be mated, engaged with, fitted to, or docked, to a corresponding docking station. Typically such docking stations are used as a power source to recharge a vacuum cleaner if that vacuum cleaner is battery powered. However, the docking station and vacuum cleaner of the examples of the invention are configured to facilitate the removal and storage or dirt and debris that is emptied from the vacuum cleaner into the docking station. The vacuum cleaner may be battery powered, which is beneficial due to the portability advantages it provides, but this is not essential. Although vacuum cleaners in accordance with examples of the invention may be operated on the docking station to clear out dirt and debris, they may also in other examples be operated on their own without being docked onto a docking station.

Advantageously the vacuum cleaning system of the examples of the invention provides a vacuum-assisted bin emptying function without the need for an additional vacuum generator in the docking station. This makes the overall system less costly and more energy efficient.

show various views of a battery-powered or cordless handheld vacuum cleanerwhich may be used in the system of the invention, thereby providing the reader with useful context.

Referring firstly to, a handheld vacuum cleanercomprises a main bodyhaving an elongate handle, a primary separation system in the form of a cyclonic separating unithaving a longitudinal axis X and a cleaning tool, in the form of a nozzle, which is secured to the cyclonic separating unit. The cleaning toolis detachable from the handheld vacuum cleaner which means it can be used for different cleaning tasks. In, the cleaning toolis in the form of a crevice tool.

However, in other examples, the cleaning toolmay be in the form of an elongated pipe or ‘wand’ which has a floor tool attached to its end distal from the vacuum cleaner. The cleaning toolin this configuration therefore allows the vacuum cleaner to be used as a stick vac. The specific form of cleaning toolwhich is used with the vacuum cleaneris not important to the inventive concept but is shown in these Figures for context and completeness.

The cyclonic separating unitextends away from the handlesuch that the cleaning toolis at the end of the cyclonic separating unitwhich is furthest from the handle. The cleaning toolextends away from the cyclonic separating unitalong the longitudinal axis X of the cyclonic separating unit.

The main bodyfurther comprises a suction generatorcomprising a motorand impellerwhich are located above and towards the rear of the handle. The components of the suction generatorare located in a motor housing or casing. The motor housingis located adjacent to the cyclonic separator unitso that airflow that exits the cyclonic separating unitflows into the motor housingto be expelled from the vacuum cleaner. The motor housingmay include a pre-motor filterlocated in advance or upstream from the motorand impeller with respect to the direction of airflow through the machine in order to filter out contaminants from the airstream that have not been separated by the cyclonic separating unit. The pre-motor filteris shown schematically inand may take various structural configurations. The pre-motor filteris positioned in a direction upstream of the motorwhen considering the airflow direction through the cyclonic separating unitand through the pre-motorin normal operation of the vacuum cleaner. However, a post-motor filter (not shown) may be provided in addition to or instead of the pre-motor filter, in some examples.

A batteryis located directly below the handle. An actuator in the form of a finger-operated triggeris provided at an upper portion of the handle. A trigger guardextends forwardly from the handle below the trigger. The handleis arranged at an anglewith respect to the longitudinal axis X of the cyclonic separating unitsuch that the handleis in a pistol grip configuration. In the example shown, a handle axis H is arranged atdegrees with respect to the longitudinal axis X of the cyclonic separating unit. The angle is the included angle between the longitudinal axis X extending forward of the handleand the portion of the handle axis H extending through the handle.

The cyclonic separating unitcomprises a primary cyclonic separatorand a plurality of secondary cyclonic separatorspositioned downstream of the primary cyclonic separator. The primary cyclonic separatoris adjacent a first end of the cyclonic separating unitand the secondary cyclonic separatorsare adjacent a second end of the cyclonic separating unitwhich is opposite the first end. The secondary cyclonic separatorsare arranged in a circular array which extend about the longitudinal axis X of the cyclonic separating unit.

The primary cyclonic separatorcomprises a separator bodyin the form of a bin having a cylindrical outer walland an end wall. The cylindrical outer walldefines a cyclonic separation chamber. In the example shown, it is the axis of the cyclonic separation chamberwhich defines the longitudinal axis X of the cyclonic separating unit. A central ductextends from the end wallto an inletof the cyclonic separation chamber.

The cleaning toolcomprises a connector portionand a nozzle portionwhich define a ductalong the cleaning tool. The connector portionhas an outer diameter which is smaller than the inner diameter of the portion of the central ductadjacent the end wallsuch that the connector portioncan be inserted into the central duct(as illustrated) thereby ensuring a rigid connection between the cleaning tooland the cyclonic separating unit. This configuration is not essential, however, and the connector portionmay be configured in other ways to mate the cleaning toolto the vacuum cleaner.

The cleaning toolis provided with retaining features (not shown) which engage with the central ductso as to secure the cleaning toolto the central duct. The cleaning toolfurther comprises an annular collarthat abuts the end wallthereby holding the end wallin the closed position, and so prevents accidental opening of the end wallwhile the cleaning toolis attached. The cleaning toolhas a manually operated catchthat is actuated in order to disengage the retaining features from the central ductin order to remove the toolfrom the cyclonic separating unit. Again, it should be noted that these mechanical details are only exemplary and, as such, the cleaning toolmay take other forms and the cleaning toolmay be connected to the vacuum cleaner bodyin other ways.

The central ductand the ductthrough the cleaning tooltogether define an inlet duct,which extends coaxially with the longitudinal axis X and through the end of the cyclonic separating unitwhich is furthest from the handle. That is, through the end wallof the separating unit. As shown here, the end wallis perpendicular to the longitudinal axis X of the machine.

The inletof the cyclonic separation chamberis spaced away from the end walland is located towards the end of the primary cyclonic separatorwhich is opposite the end of the cyclonic separating unitto which the cleaning toolis connected. The cyclonic separation chambertherefore extends about or surrounds the portion of the inlet duct,formed by the central duct. A first portion of the central ductleading from the end wallextends along the axis X of the cyclonic separation chamber. A second portion of the central ductextends from the first portion to the inletof the cyclonic separation chamber. The second portion extends in a direction which has both radial and circumferential components with respect to the cyclonic separation chamberso as to promote rotational flow within the cyclonic separation chamberduring use.

The end walland the portion of the cylindrical outer walladjacent the end walldefine a dirt collector, which is in the form of a dirt collecting bin or more simply ‘dirt bin’, in which dirt separated from the incoming flow by the primary cyclonic separatoris collected.

The end wallis connected to the cylindrical outer wallby a pivotand is held in a closed position by a user-operable catch. The end wallcan be moved from the closed position, in which dirt is retained within the dirt bin, to an open position, in which dirt can be removed from the dirt bin, by releasing the catchand pivoting the end wallaway from the end of the cylindrical outer wall. The end wallcan therefore be considered to be a bin door of the dirt binwhich closes bin openingof the dirt bin.

A cylindrical shroudis disposed centrally within the cyclonic separation chamberand extends coaxially with the axis of the chamber. Aperturesprovided through the shrouddefine a fluid outlet from the cyclonic separation chamber. Note that aperturesare shown as being distinct holes in, although it is envisaged that in other examples the aperturesmay be smaller and more numerous e.g. as part of a fine mesh or perforated membrane.

A duct, which is formed in part by the shroud, provides fluid communication between the outlet from the cyclonic separation chamber formed by the aperturesand inletsof the secondary cyclonic separators. Each secondary cyclonic separatorhas a solids outletat one end which is in communication with a fine dust collectorthat extends along the side of the primary cyclonic separator. A fluid outletat the end of each of the secondary cyclonic separatorsopposite the solids outlet.

In use, the handheld vacuum cleaneris activated by a user pressing the triggerwith an index finger. Dirty air is drawn by the suction generatorthrough the inlet duct,and through the inletinto the cyclonic separation chamber. The rotational flow promoted by the second portion of the central ductwithin the cyclonic separation chamberproduces a cyclonic action that separates relatively heavy or large dirt from the air. Cyclonic vacuum cleaners with dual cyclonic systems or a plurality of cyclonic systems are well-known in the art. Therefore, this discussion is provided for context and to illustrate one type of vacuum cleaner that is suitable for use within the examples of the invention.

Typically, the vacuum cleaneris held such that the cyclonic separating unitpoints downwardly from the handle. Dirt separated in the cyclonic separation chambertherefore falls under the influence of gravity into the dirt bin. The partially cleaned air passes through the aperturesin the shroudand is drawn along the ductto the secondary cyclones. Smaller and lighter particles of dirt are separated from the air by the secondary cyclonesand expelled through the respective solids outlets into the fine dust collector. The cleaned air exits the secondary cyclonesvia the respective fluid outletsof the secondary cyclonesthrough the pre-motor filterand suction generator, and the out of vents (not shown) at the rear of the main body.

shows the vacuum cleanerbeing emptied in a known way. In order to empty the dirt binand the fine dust collector, the user first disconnects the cleaning tool. Then, whilst gripping the handle, the user points the vacuum cleanertowards a suitable receptacle (e.g. a waste bin or bag) into which the dirt is to be emptied. The catchis then released by the user and the end wallpivoted from its closed position into its open position.

In an alternative arrangement, the inlet duct,may be spaced from the axis of the cyclonic separating unit. Nevertheless, the cyclonic separating unitmay be arranged to extend partly around a portion of the inlet duct or to entirely surround a portion of the inlet duct,. For example, the inlet ductmay be recessed into the side of the cyclonic separating unitsuch that duct extends within the profile of the cyclonic separating unitwhen viewed along the axis of the cyclonic separating unit.

When emptying the vacuum cleaner, it will be appreciated that dirt and dust is ejected from the dirt binthrough the action of gravity. It is also known to include a mechanical agitator such as a plunger to urge the dirt out of the dirt bin. However, in an emptying operation, fine dust tends to float upwards which is undesirable for the user. Some examples of the invention are directed to address this issue.

Turning now to, there is shown a schematic representation of the handheld vacuum cleanerthat is dockable with a docking stationthereby to define a vacuum cleaning systemalthough in other examples the vacuum cleaning systemmay not require a docking station. The vacuum cleanershown inis similar in configuration to that shown in. Therefore the same reference numerals will be used to refer to the same or similar parts.

In, the handheld vacuum cleaneris spaced from the docking station, whereas inthe vacuum cleaneris docked onto the docking station. As will become apparent from the discussion that follows, the vacuum cleaneris operable in a bin emptying and/or ‘self-cleaning’ mode or of operation during which dirt contained in the dirt binis sucked into the docking stationdue to a partial vacuum therein which has been generated by the vacuum cleaner.

Reference firstly will be made to the docking station. In this example, the docking stationhas a generally cylindrical bodyand is taller than it is wide. More specifically, its vertical height (as orientated in the Figures) is approximately three times its width, i.e. its diameter. It should be noted that the geometry shown here is only exemplary and as such the docking stationneed not be cylindrical and may be differently shaped.

The bodyof the docking stationis defined by a thin wallhaving a base endand a top end. The base endrests on the floor (not shown) and stabilisation is benefitted by a flared standor foot. The footmay be removable from the docking stationand is optional.

The top endof the docking stationprovides an interfacethat is configured to engage with the vacuum cleaner. In principle the interfacemay be configured in various ways, but it should provide the functionality that the central ductof the vacuum cleaneris able to communicate with the interior of the docking stationand that the pivotable end wallof the dust collectoris able to open into the interior of the docking stationthereby exposing its contents.

In the illustrated example, the interfaceis configured as an annular closure located on the top endof the docking station. The interfacecan be fixed to the bodyof the docking stationso as to be removable and/or to be pivoted with respect to the body. Alternatively the interfacemay be a fixed e.g. integral part of the docking stationsuch that it cannot be removed, although currently this is not considered preferable. An interfacethat is removable may permit the replacement of a differently configured interface that is adapted for a different configuration of vacuum cleaner, as will be made apparent later.

The annular shape of the interfacedefines a central openingthat is dimensioned to be comparable to that of the separator bodyof the vacuum cleaner. The central openingtherefore receives the separator bodyof the vacuum cleaner. Preferably the central openinghas a suitable sealing arrangement (not shown) such as a rubber lip seal or a type of fringe that seals against the outer surface of the separator bodyalthough this is considered optional.

Turning now to the interior of the docking station, init can be appreciated that the docking stationhas a compartmentalised interior volume, in this example. In particular, the docking stationis configured to define a dirt storage chamberand an intermediate chamber or antechamber. Both of these chambers,are surrounded by the interior volumethat is bounded by the outer wallof the docking station. The intermediate chamberprovides a volume of space that leads from the interfaceof the docking stationto the dirt storage chamber. The intermediate chamberhas a chamber wallthat is shaped in the form of a tapered chute and, as such, has a larger upper portionwhich leads to a narrower throat portion. The vertical height of the throat portionis, in the illustrated example, less than the vertical height of the upper portion. However, in other examples, the length of the throat portionmay be longer than this, which may provide benefits in terms of preventing dirt blow back from the dirt storage chamber.

A lower end of the throat portionterminates at the dirt storage chamber. The dirt storage chambermay depend or hang from the intermediate chamber, more specifically from the throat portion, in this example. Thus, the dirt storage chambermay be removably clipped or otherwise be attached to the intermediate chamber.

A valveseparates the intermediate chamber, and more specifically the throat portionthereof, from the dirt storage chamber. In this example, the valveis a one-way or ‘check’ valve that is configured to permit dirt to travel into the dirt storage chamberfrom the intermediate chamber, under the influence of a vacuum, as will be explained. Once pressure has normalised, the valvecloses to prevent dirt or dust travelling back into the throat portionfrom the dirt storage chamber.