The present invention is concerned with a device and method for removing contamination and the like from air. Specifically, but not exclusively, the device is concerned with collecting unwanted airborne matter in different environments such as cities, polluted areas, industrial environments or the like.

In industrial environments, such as factories, unwanted debris and pollutants are often released into the air within the building. This may be a direct result of the processes that are taking place, for example machining operations creating air borne particles. Alternatively, unwanted debris of contamination may be released accidentally, for example a malfunction or accident in a process causing debris to be released into the air within the building inadvertently.

Contamination in the form of airborne particles presents a number of problems in a factory environment. For example, the contamination may present health and safety issues for the operatives working in the environment. The contamination may also be detrimental to the processes that are taking place. Many processes, particularly in the electronics sector, require high levels of air quality i.e. low levels of contamination to prevent processes becoming defective as a result of the contamination. Furthermore, contamination can cause breaches of environmental legislation or laws. Still further, in some processes high levels of airborne matter can present fire and explosion risks.

A variety of conventional systems have been developed to address these problems in the art. For example, air filter systems are commonly installed in factories. Such systems draw air through one or a series of filters which entrap the airborne contaminants (particles/dust or the like) within the filters. As the systems function the air within the factory is slowly cleaned. These systems are effective but need to run continuously and have to process all of the air in the building. For large factories this could be a large volume of air to clean. Other solutions to the problems discussed above include sealing the factory and incorporating airlocks and the like to prevent contaminants entering the building. The machinery can also be enclosed in housings that prevent airborne particles being released. Such systems are very effective but are also extremely expensive to install and are thus only used in very specific applications such as in semiconductor manufacturing.

The present inventor has established an alternative arrangement that can effectively remove contamination from industrial environments and the like. Advantageously the arrangement is inexpensive to install in an industrial environment and allows specific parts of the environment to be targeted for cleaning. This allows localised contaminated areas to be quickly and effectively cleaned of contamination. The inventor has also identified an additional application for the technology that offers environmental benefits on a much larger scale, namely the application to a ground based vehicles.

Summary of the Invention

Aspects of the invention are set out in the accompanying claims. Viewed from a first aspect there is provided a filtration system for a ground-based vehicle wherein air is caused to pass through a semi-permeable membrane, the filter comprising a pair of air permeable electrodes wherein a potential difference is applied between the electrodes and wherein the air is caused in use to pass through a both electrodes and the semi-permeable membrane.

Thus, the technology described herein with reference to an air-borne vehicle can equally be applied to a ground based vehicle. Air cleaning on a far greater scale can thus be realised in a cost effective way. The potential difference may be provided by the electrical systems of the vehicle. Thus a separate electrical supply is not required.

The semi-permeable membrane may be a synthetic fibre or glass fibre, such as a filter cloth which is electrically conductive as one example.

The semi-permeable membrane also be in the form of a multi-layered filter cloth having inside electrically conductive wiring. The cleaning effect can then be increased for the same cross-sectional area. Such layers may be pressed or otherwise assembled together. The system may also include a selectively attachable vacuum system arranged in use to cause a reverse flow of air through the filtration system. Thus the system can be conveniently cleaned. The vacuum systems may have a concave cover attached on top of the filtration system and a hose arranged to supply a vacuum. The system may further comprise a charging connection point for electric cars and wherein the vacuum is generated simultaneously whilst the car is charged.

In one embodiment the system is in the form of a channel through which air is arranged to pass. The channel may be arranged in any suitable position including, but not limited to, a roof, bonnet or spoiler of a vehicle. Viewed from another aspect there is provided a method of cleaning air using a ground-based vehicle, wherein the ground based vehicle comprises a filtration system described herein.

The vehicle may be any suitable ground based vehicle including, for example, a passenger car.

Viewed from another aspect there is provided an air filtering apparatus comprising a plurality of filter surfaces, wherein each filter surface comprises a fan associated with the filter surface and arranged in use to cause air to pass over or through the filter surface, wherein at least some of the plurality of fans are operable to generate sufficient lift to cause the apparatus to become airborne.

Thus, according to an invention described herein, an air filter is provided which incorporates a fan and filter arrangement to cause air to pass through or over a filtering surface. In addition however one or more of the fans also creates a sufficient airflow (thrust) to cause the apparatus to become airborne.

Causing the apparatus to become airborne allows the filter arrangement to be controlled and positioned in 3 dimensions i.e. the apparatus may be controlled and moved into zones or areas of contamination which may not otherwise be reachable from ground level.

The filtering surface may be any suitable surface arranged to entrap or collect debris. The type and porosity of the filter surface may be selected depending on the degree of filtering required. For example, to selectively remove large debris a coarse filter (i.e. a filter with relatively large holes or porosity) may be used. In another example, electric air cleansing may be used, such as a polarised-media electronic air cleaner or ioniser purifier to collect smaller debris with a help of electrical forces. Furthermore, in other examples, different types of filters may be used.

On rotation the fan associated with a respective filter surface advantageously causes air to be drawn (pulled) and/or pushed through or past the filter surface causing debris to be collected or entrapped. The fans may be operated by independent motors or in groups using a suitable drive train. In one arrangement each of said plurality of filter surfaces may be located in a circular housing wherein the housing is concentric with a respective fan. In effect the filter surface is a cylinder surrounding the fan such that air flow and vortices caused by the rotation of the fan proximate the filter surface causes debris to come into contact and/or pass through the surrounding filter.

In some examples, the fans may be oriented at an angle with respect to the housing. In other examples, some but not all of the blades of the fans may be oriented at an angle with respect to the housing.

Some or all of the fans may advantageously have a vertical axis of rotation such that rotation of the fan about the axis directs air in a downwards direction to generate the desired lift. All or a subset of the fans may be arranged to generate lift or thrust.

Advantageously the fans may not all rotate at the same speed but may be selectively controllable. For example, the fans arranged to generate lift and movement of the apparatus may operate at a higher rotational speed that the fans arranged to cause filtration. All or a sub-set of the fans and associated fan housing may be movable with respect to the body of the apparatus. Thus air can be directed in different directions to allow for control of movement of the apparatus. A suitable control arrangement may be used to remotely control the operation of the fans and thus the movement of the apparatus through the air. As discussed above the filter surfaces may be arranged radially with respect to the tips of the fan blades. In effect a cylindrical housing is defined around each fan. Advantageously the filter surfaces may be concentric with the rotational axis of a respective fan with the hub of the fan in the centre of the cylinder. The filter surface itself may be in the form of a simple porous surface and/or may include cavities or the like to entrap larger debris. A range of surface porosities may be used. The surfaces may also comprise standard activated carbon filters.

The plurality of filter surfaces across the apparatus may be dissimilar i.e. some or all of the plurality of filter surfaces may have differing filter properties. For example one filter may be arranged with an activated carbon filter and another with a coarse porous filter. Thus, a range of filtering may be achieved simultaneously. Alternatively each filter may be selectively operated so that different debris can be filtered perhaps at different locations for example.

In some examples, different filter portions may be used in a single filter surface.

The apparatus may be fitted with a pollution detector for example able to measure the density of debris in the air.

A filter surface may also be arranged so as to be located over the aperture through which the fan pushes and/or pulls air i.e. the surface is located axially with respect to the fan. Thus, debris can be collected on the surface by virtue of the air flow caused by each fan's rotation. Advantageously each filter may be in the form of a detachable assembly. Thus, a filter that is full of debris or even damaged can be changed for a new, replacement filter. The filters may for example be independently changed or changed as a single unit thus requiring only 1 action to change the filters of the apparatus.

For example, the filter surfaces may be located in a housing arranged to hold and support the filter surface. The housing may in turn have a coupling allowing the housing to be selectively coupled and decoupled from the apparatus. Any suitable coupling could be used including quick release couplings, latch couplings or even Velcro couplings.

The fans (and associated filter surfaces) may be arranged in any suitable configuration. For example the fans may be arranged in a ring shape defining a central region to accommodate a battery supply and control arrangement.

The movement and filtration tasks may be divided between sub-sets of fans. For example, one sub-set of the fans may be configured to provide vertical lift to the apparatus and another sub-set may be arranged to filter air. Viewed from another aspect there is a method of filtering a volume of contaminated air, the method comprising directing one or more filtering apparatuses as described herein into the volume of contaminated air so as to collect contaminants from said volume.

The debris may be conveniently collected from a remote location and returned to a contamination collection location where the filters may be conveniently cleaned or replaced by means of the couplings described above. For example, the contamination collection location may be a landing site or docking station arranged to receive the filter arrangement.

Figures

Aspects of the invention will now be described, by way of example only, with reference to the accompanying figures in which:

Figure 1 shows a base view of the air filtering or purification apparatus;

Figure 2 is an orthogonal view of the apparatus; Figure 3 also shows two positions for the filter surfaces according to the apparatus;

Figure 4 shows an alternative arrangement of housing according to an embodiment of the invention; Figures 5, 6 and 7 show additional views of the apparatus;

Figure 8 shows a schematic of a building in which the apparatus may be deployed; and Figure 9 shows a further application in a moving vehicle;

Figure 10 shows a roof air purification channel on a passenger vehicle; Figure 1 1 shows a front view of the channel from figure 10; Figure 12 shows a front grille mounted alternative embodiment;

Figure 13 shows a cross-section of a car radiator position of the invention; Figure 14 shows an alternative configuration to that shown in figure 13 ; and

Figure 15 shows an example cleaning system for the filter.

While the invention is susceptible to various modifications and alternative forms, specific embodiments are shown by way of example in the drawings and are herein described in detail. It should be understood however that drawings and detailed description attached hereto are not intended to limit the invention to the particular form disclosed but rather the invention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the claimed invention. It will also be recognised that alternative embodiments may be used in any suitable combination.

Detailed Description

Figure 1 shows a base view of the air filtering or purification apparatus 1 according to an invention described herein. The apparatus comprises a plurality of circular housings 2a - 2h arranged in a generally ring configuration around a central region 3.

Although circular housings are shown in a ring arrangement it will be recognised that other arrangements may equally be employed. Each housing 2a-2h is connected to adjacent housings to form a rigid body 4.

Each of the housings comprises a centrally located propeller or fan 5 which in the embodiment shown has a pair of fan or propeller blades. Each propeller or fan 5 is arranged to rotate about a hub 6 which is centrally located with respect to the circular housing. Thus, the fan blades rotate within the circular opening defined within the housing as shown in figure 1 .

The hub 6 may comprise an electrically operated motor (not shown) which causes the blades of the fan to rotate. Each hub is supported and connected to the central region 3 by an arm 7. In an arrangement which the hub contains the electric motor the arm 7 may comprise the electrical wiring needed to power the motor.

In an alternative arrangement the motor may be located in a suitable housing within the central region 3. In such an embodiment the arms 7 may incorporate a drive train communicating rotational movement to the hub. The hub may in turn comprise suitable gearing to convert the rotation within the arm to rotation of the fan blades.

The central region 3 comprises a battery power supply (not shown) and controller (not shown). In other examples, the controller may be located elsewhere in the air filtering or purification apparatus. The controller is configured to receive signals from a remote control unit to selectively and independently control each of the fans (discussed further below). Such remote control systems and the necessary electronics and communication arrangements needed to remotely control electric motors would be known to someone skilled in the art.

Figure 2 is an orthogonal view of the apparatus. As shown in figure 2 the apparatus comprises an upper ring 8 of housings 2a - 2h and a lower ring 23 of housings 24a - 24h. In the example shown in figure 2, the lower ring 23 of housings 24a - 24h is used for support and protection of the fans. In other examples, the housings 24a - 24h could be used for further filters.

Figure 2 also illustrates the support legs 9 which provide the support when the apparatus lands and protects the body and fans from damage. Figure 2 also shows one of the filtration surfaces 10 which are described in more detail with reference to figure 3.

Figure 3 is a cross-section through one of the housings (2a) and shows the fan 5 and hub 6 located centrally with respect to the axis x of the housing. The fan blades rotate about the axis x-x. In alternatively arrangements one or more of the fans may be inclined to the vertical by a predetermined angle a to improve the stability of the apparatus in flight.

Figure 3 also shows two positions for the filter surfaces which may be employed independently or simultaneously i.e. each housing 2a may incorporate both an axial filter surface and a radial filter surface.

The axial filter surface 10 (also shown in figure 2) is located across the upper aperture of the housing 2a and comprises a porous membrane which has a predetermined porosity i.e. the holes in the filter are a predetermined size. The filtration surface 10 is located in a direction further along the axis x-x with respect to the housing 2a in order to allow the fans access to make-up air.

The axial filter serves three purposes: (i) firstly the axial filter prevents any large objects being ingested into the housing by the airflow created by the rotating fan. This advantageously prevents damage to the fan blades and allows the apparatus to move through zones containing larger airborne debris; (ii) secondly the axial filter can act as a first coarse filter to collect and entrap larger debris contained within the air through which the apparatus is directed. This provides a first step filtering action. (iii) thirdly, the axial filter acts as a fan cover to protect the fan in the event of, for example, collisions.

The axial filter may be a simple wire mesh or gauze for example. Importantly, the axial filter must not be such that it prevents airflow passing through the filter surface, particularly for the fans that are functioning to provide the desired lift. Thus, some housings 2a - 2h may be provided with finer filter surfaces than others. More specifically, housing that are configured to provide lift may comprise a coarser filter surface than housings that are configured to provide filtration. Similarly the fans may be configured to operate at different rotational speeds.

The second filtration surface is the radial filtration surface 1 1 which is also shown in figure 3. The high fan speeds causes high speed vortices and circulating air flows within the housings. This air flow causes the air to be forced against and to pass over the inner surfaces 1 1 of the housing. This advantageously allows a second filtration action to be established. Thus, the radial filtration surface 1 1 may comprise protuberances or entrapment recesses to collect a finer level of airborne debris.

Alternatively, or additionally, the surface may comprise an activated carbon surface to filter the air passing over it. An activated carbon layer on the surface of the radial filtration surface may remove debris by means of chemical absorption. Such an arrangement allows for extremely small contaminants to be collected or filtered from the zone through which the apparatus passes.

Figure 4 shows an alternative arrangement of housing 2a. In figure 4 a single wall of the housing is shown.

As shown the fan 5 causes air to flow in a vertical direction (shown by arrows 12). As well as vertical movement of the air vortices 13 are also generated by the air flow around the tip of the blade 5. In the embodiment shown in figure 4 the housing 2a comprises a plurality of apertures 13 which are formed by vanes 14 located on the inner surface of the housing 2a. The vanes are inclined such that airborne debris 15 entrained within the airflow is captured by the vanes and directed to a hopper or collection portion 16 of the housing 2a.

This represents another way in which filtration can be achieved according to the apparatus.

Figures 5, figure 6 and figure 7 show plan and side views of the apparatus respectively. Figure 7 also illustrates the inclusion of the fan 5 with respect to the vertical. In the embodiment shown the angle is shown by reference a.

Figure 8 shows as schematic of the apparatus in use. A building 17 is shown in which a cloud or zone of contamination 18 has formed and which requires filtration.

The filtering apparatus 1 is first positioned on a docking station 19 which provides recharging facilities and filter changing facilities for the apparatus. Filters are cleaned periodically or during every visit to the docking station 19 during the battery replacement and tool changing process. Cleaning is carried out using a vacuum cleaner or the like. In some examples, multiple vacuum cleaners may be used, i.e. one for each filter. In other examples, one vacuum cleaner may be used which moves around the robot and cleans each of the filters. This could be implemented with a carousel on the roof or floor of the dock. Alternatively, the filtering unit itself can move around its own axis so all the filters can be cleaned. The vacuum cleaner or vacuum cleaners can also include an arm and joints which help with the cleaning of the filters in the bottom of the unit. In some examples, a brush may be used in the cleaning process. The brush may be attached to a robot hand.

Changing the filters can happen about once in a month and it will be implemented with a robot hand (or some other changing system) by detaching the whole frame and replacing it with a new one. Also single filters may be replaced using the same system.

The apparatus 1 is activated and directed either manually by an individual or automatically towards the zone 18 along flight path 20. The apparatus passes through the zone 18 collecting debris using the axial and/or radial filter surfaces (depending for example on the contamination found) and then returns along flight path 21 to the docking station 19. The filters can then be changed/cleaned and the same flight path route repeated. In a further embodiment of a system described herein a plurality of filtering apparatuses 1 may be used sequentially or in parallel to detect and filter airborne contamination from within the building or other space.

Sensors 22 could, in another embodiment, detect airborne contamination and send data to the controller of the apparatus which can then be used to automatically remove the detected contamination without user control i.e. an automated air filtration system. In a further enhancement the severity or danger associated with multiple zones 18 could be determined by such detectors 22 and the zone prioritised for filtration. For example, a human health danger caused by contamination may be filtered as a priority over other contamination. In other examples, the apparatus 1 itself may contain sensors for detecting airborne contamination.

Alternative Embodiment The inventor has also established that the electric air cleansing (such as a polarised-media electronic air cleaner or ioniser purifier) described above with reference to an airborne filtration system can also be employed in other applications for moving vehicles. One such example is a passenger car. Referring to figure 9 the two different systems are illustrated, a first airborne filtration device and a second modified ground based vehicle which can also act to purify and clean the air.

As shown in figure 9 the airborne vehicle 1 captured debris and impurities 23 from the air at an altitude. In an alternative arrangement a ground based vehicle 24 can similarly collect debris and impurities from airflows 25 closer to the ground. It many instances, for example on busy roads, there may in fact be a higher density of debris and impurities in the airflow such as flow 25, particularly in heavy traffic.

The location of the filtration system may vary depending on the vehicle. Although a passenger car is illustrated it will be recognised that other vehicles could also be modified with a technology described herein. For example heavy goods vehicles, busses, agricultural or machinery or any other mode of transport where the vehicle moves through the air may be used.

Referring to figure 10, there is shown a modified roof structure 26 of a passenger vehicle 24. In effect the roof has been provided with a raised portion or possibly a hollow portion which comprises an inlet 27 and an outlet 28. As the vehicle travels along air enters the inlet 27 and travels along an air purification channel 29 before reaching an outlet 28 where the air is release back to atmosphere. The purification channel 29 allows the air to be treated in a continuous process and air continuously flows through the channel. This is illustrated by the flow lines 25 in figure 10.

Within the channel the air passes between charged surfaces and against a filtration film. The film captures debris as the air flows along and through the channel. The electrical charge may be provided across the channel by means of electrodes further enhances the purification process by causing debris to be attracted to the film.

The electrodes may be continuous along the length of the channel or may be a series of discrete electrodes arranged along the channel's length. The channel may also incorporate debris receiving recesses or the like in the same manner as are used in the airborne arrangement described above.

The first grey area A pictured in Figure 10 may include a miniature wind turbine that powers the filter and excess electricity can be used for the car.

The second grey area B pictured in Figure 10 is a charged surface. It is analogous to the airborne filter described above, There is another charged surface at the end of the channel, which has an opposite charge. The darker grey area C in front of or around the charged surface at the end of the channel is a filtration film. It is also analogous to the airborne filter arrangement described above.

The system may equally be applied to other parts of a vehicle i ncluding the bonnet or spoiler for example where suitable inlets and outlets may be provided.

Figure 1 1 shows a front view of the inlet 27 of the roof mounted filtration passage. Figure 12 shows an alternative position at which the system may be used, namely at the front of the vehicle where the vehicle received air for cooling and combustion. This is the radiator inlet.

Referring to figure 13 a cross-section of the front of the vehicle is shown. The arrangement comprises a pair of electrically charged surfaces 30, 31 which are arranged in the airflow of the vehicle downstream of the radiator inlet 29. The surfaces are air permeable such that air can pass through them. They are also however electrically conductive such at a potential difference AV can be applied between the surfaces my means of voltage from , for example, the car's battery 32 or from the wind turbine of Figure 10. Alternatively, there may be a separate battery for this system or a dynamo or alike, They can be conveniently connected by means of electrical cables 33. The arrangement also comprises a filtration film 34 which is arranged again with the airflow from the radiator inlet 29 and extends across the charged surface 31 (and additionally across the front of the radiator 36). The film is also permeable to air but has a filter density such that debris 35 can be collected on its leading edge surface. In use air passes through the radiator inlet 29, through the charged plates and through the radiator so as to perform its normal use of cooling the car's radiator. However, because of the charged plates and the film debris can be continuously collected as the car moves through the air. Air which is discharged from the radiator is thus cleaner that the air that enters the radiator.

Figure 14 shows a still further embodiment of the invention in which the charged plates are arranged on the opposing side (the downstream side) of the car's radiator. The reference numerals correspond to the features described with reference to figure 13. Here a wind turbine 37 is the same as A in Figure 10.

The film described herein may be, for example, a synthetic fibre or glass fibre from a suitable manufacturer. For example, a filter cloth may be used which is electrically conductive. One possibility is to have a multi-layered filter cloth having inside electrically conductive wiring (e.g. copper wiring) evenly spreading the electric charge across the filter. The layers are pressed or otherwise assembled together. Figure 15 shows a vacuum system that has a concave cover attached on top of the filtration system, and a hose (same as with the home vacuum cleaner). For example the cover can be attached to the filtration system with four clips on the each corner of the cover. In Figure 15, F marks a charging connection point for electric cars. E is a counterpart for F. This is designed for the electric car charging spots. The cleansing of the filter happens at the same time as charging of an electric car. The vacuum in itself is the same part as the charger of an electric car.

The other figure shows the vacuum / charger attached to the car. The alternative is to have it without the charger or the charger is disabled for combustion engine cars or non-compatible electric cars so that it can be used for any vehicle.

The film or cloth may be intermittently cleaned by causing a reverse flow of air into a suitable collection device. This could for example be by means of a suitable industrial or other vacuum system.

It will be recognised that whilst three examples of positioning the arrangement are described herein the system could be installed at any suitable location of a vehicle where there is an airflow.

An arrangement as described with reference to the second embodiment of an invention provides the potential to purify and clean a significant volume of air if it is applied to a sufficiently large number of vehicles. For example, millions of vehicles could be modified with such technology and by means of their normal everyday use could clean significant volumes or air.

It will also be recognised that whilst the embodiment refers to a conventional passenger car the system could equally be applied to an electric vehicle which necessarily has the required electric power source needed to operate the system.