GB2574477A

GB2574477A - Air purifier

Info

Publication number: GB2574477A
Application number: GB1809473.0A
Authority: GB
Inventors: Rowe Matthew
Original assignee: Matr Tech Ltd
Current assignee: Matr Tech Ltd
Priority date: 2018-06-08
Filing date: 2018-06-08
Publication date: 2019-12-11
Also published as: GB201809473D0

Abstract

An air purifier 100 comprises an elongate housing comprising an air inlet 10 and an air outlet 12,14, wherein the elongate housing has a longitudinal axis. The air purifier also includes a photocatalytic reactor 40 and a fan configured to direct air through the elongate housing from the air inlet to the air outlet via the photocatalytic reactor in an air flow direction. The air purifier also comprises a UV light source 20 configured to direct UV light onto the photocatalytic reactor. The photocatalytic reactor is slanted to deflect, obliquely to the longitudinal axis air flowing in the air flow direction from the air inlet to the air outlet. Further inventions are disclosed relating to a photocatalytic air purifier characterised by a first air quality sensor, a second air quality and a processor; a photocatalytic air purifier characterised by a first air outlet and a second air outlet; an air purification system characterised by a photocatalytic air purifier and a remote control comprising an air quality sensor and a wireless interface for communicating with the air purifier, and the air purifier comprises a wireless communications interface; a remote control for an air purifier and a computer-implemented air quality monitoring system and a method of monitoring air quality.

Description

Air purifier

Field of the invention

The present disclosure relates to an air purifier, a remote control for an air purifier, an air purification system, a computer-implemented air quality monitoring system and a method of monitoring air quality.

Background

Some air purifiers make use of ultraviolet photocatalytic oxidation (UV-PCO) technology to purify air. UV-PCO systems can convert volatile organic compounds (VOCs) to harmless compounds. For example, VOCs such as hydrocarbons can be converted into water and carbon dioxide.

UV-PCO systems in general work in the following manner: when a UV light source is shone onto a photocatalyst, the photocatalyst interacts with oxygen and airborne water molecules to form active oxidation species such as hydroxyl radicals. The hydroxyl radicals then attack the contaminants and initiate an oxidation reaction that converts the contaminants into less harmful compounds, such as water and carbon dioxide. An example UV-PCO control system is described in EP08724109.

UV-PCO are advantageous because they do not require cartridges. However, there is a desire for air purifiers, such as UV-PCO air purifiers, to be as efficient as possible.

Summary of the invention

Aspects of the invention are as set out in the independent claims and optional features are set out in the dependent claims. Aspects of the invention may be provided in conjunction with each other and features of one aspect may be applied to other aspects.

In an aspect there is provided an air purifier. The air purifier is a UV-PCO air purifier. The air purifier comprises an elongate housing comprising an air inlet and an air outlet, wherein the elongate housing has a longitudinal axis. The air purifier also comprises a photocatalytic reactor (comprising a photocatalyst such as titanium dioxide), a fan configured to direct air through the elongate housing from the air inlet to the air outlet via

-2the photocatalytic reactor in an air flow direction and a UV light source configured to direct UV light onto the photocatalytic reactor. The photocatalytic reactor is slanted to deflect, obliquely to the longitudinal axis, air flowing in the air flow direction from the air inlet to the air outlet. In some examples the UV light source emits UV light in the wavelength of 200 to 400 nm, for example 300 to 400 nm, for example 375 nm.

By providing an air purifier that deflects air flowing through the air purifier in this way, the air may be better mixed, therefore providing an increased production of hydroxyl radicals and additional an increased neutralisation of compounds such as VOCs.

The UV light source may be configured to direct light obliquely onto the photocatalytic reactor. The photocatalytic reactor may be shaped to rotate air flowing in the air flow direction in at least a part-circular motion relative to the longitudinal axis. In some examples the photocatalytic reactor forms at least a part-turn of a helix. In some examples the photocatalytic reactor comprises at least two photocatalytic reactor plates transverse to each other along the air flow direction. The photocatalytic reactor may be porous. For example, the photocatalytic reactor may comprise an open cell material, for example a foam/sponge. The photocatalytic reactor may be made from plastic, such as polyester-based polyurethane foam. The photocatalytic reactor may be coated in a layer of photocatalyst such as titanium dioxide, TiO2. The photocatalytic reactor may comprise 10 to 80, for example 35, pores per inch, PPI.

By directing light obliquely onto the photocatalytic reactor in this manner, a greater surface area of the photocatalytic reactor may be exposed to the UV light. This in turn may lead to an increased production of hydroxyl radicals and an increased neutralisation of compounds such as VOCs.

The air purifier may further comprise a filter comprising a washable non-woven fabric between the air inlet and the fan, wherein the filter is configured to allow the passage of air therethrough. The filter may comprise a synthetic fibre.

In some examples the air purifier further comprises a first air quality sensor such as a CO and/or VOC sensor exterior to the air purification system and a second air quality sensor

-3such as a CO and/or VOC sensor proximal to the air outlet, and wherein the air purification system comprises a processor configured to (i) receive signals from the first and second air quality sensors and (ii) make a determination of the air purifying efficacy of the air purifier. It will be understood that the first air quality sensor and/or the second air quality sensor may each comprise a plurality of sensors, such as a VOC (air quality) sensor, carbon monoxide (air quality) sensor, light brightness lux sensor, light colour sensor, temperature sensor, humidity sensor and pressure sensor.

In another aspect there is provided a photocatalytic air purifier. The photocatalytic air purifier comprises an air inlet and an air outlet, a first air quality sensor such as a CO and/or VOC sensor exterior to the air purifier and a second air quality sensor such as a CO and/or VOC sensor proximal to the air outlet. The air purifier comprises a processor configured to (i) receive signals from the first and second air quality sensors and (ii) make a determination of the air purifying efficacy of the air purifier. The air purifier may further comprise a fan configured to direct air from the air inlet to the air outlet via a photocatalytic reactor in an airflow direction.

In examples where the air purifier has a processor, the processor may be configured to control the speed of the fan based on the determination of the air purifying efficacy of the air purifier.

In some examples the air outlet comprises a first air outlet for directing air away from the air purifier in the same direction as the longitudinal axis, and a second air outlet for direction air away from the air purifier in a direction transverse to the longitudinal axis, and wherein the air purifier is operable to direct air away from the air purifier via either the first air outlet or the second air outlet.

In another aspect there is provided a photocatalytic air purifier. The photocatalytic air purifier comprises an elongate housing comprising an air inlet and an air outlet, wherein the elongate housing has a longitudinal axis, and a fan configured to direct air from the air inlet to the air outlet via a photocatalytic reactor in an air flow direction. The air outlet comprises a first air outlet for directing air away from the air purifier in the same direction as the longitudinal axis, and a second air outlet for direction air away from the air purifier

-4in a direction transverse to the longitudinal axis, and wherein the air purifier is operable to direct air away from the air purifier via either the first air outlet or the second air outlet.

In some examples the second air outlet has a smaller cross-sectional area than the first air outlet such that air directed through the second air outlet travels at a greater speed than air directed through the first air outlet. In some examples the air purifier further comprises a selector coupled to the air purifier and configured to block at least one of the first air outlet and the second air outlet, wherein the selector is operable to vary the degree to which the first air outlet and the second air outlet are blocked by the selector between (a) a first configuration where the first air outlet is open and the selector blocks the second air outlet, and (b) a second configuration where the selector blocks the first air outlet and the second air outlet is open.

The air purifier of any of the above aspects may be provided as part of an air purification system. The air purification system may also comprise, in addition to the air purifier, a remote control. The remote control comprises an air quality sensor, and may also comprise a GPS or other location tracking device/sensor, and is configured to communicate wirelessly with the air purifier to control the speed of the fan of the air purifier based on at least one of:

(i) an air quality measurement determined based on signals received from the air quality sensor of the remote control; and (ii) the proximity of the remote control to the air purifier.

In another aspect there is provided an air purification system comprising a photocatalytic air purifier and a remote control. The air purifier of the air purification system comprises an air inlet and an air outlet, and a fan configured to direct air from the air inlet to the air outlet via a photocatalytic reactor in an air flow direction along a longitudinal axis. The remote control of the air purification system comprises an air quality sensor and a wireless interface for communicating with the air purifier. The air purifier of the air purification system comprises a wireless communications interface for communicating with the remote control, and a processor coupled to the wireless communications interface and to the fan. The processor is configured to receive signals from the air quality sensor of the remote control and to control the speed of the fan based on at least

-5one of:

The air purifier may also comprise a wireless charging interface, and the remote control may also comprise a wireless charging interface configured to couple with the wireless charging interface of the air purifier for charging a battery of the remote control.

The remote control of the air purification system may be configured to record air quality measurements as a function of time and location. In such examples, the air purification system may be configured to communicate with a remote device that aggregates air quality measurements from a plurality of locations as a function of time, and map the air quality measurements to a transport infrastructure. In such examples the remote device may be configured to determine a route to take on the transport infrastructure based on the air quality measurements.

The remote control may also comprise other sensors, such as a VOC (air quality) sensor, carbon monoxide (air quality) sensor, light brightness lux sensor, light colour sensor, temperature sensor, humidity sensor and pressure sensor.

In some examples the remote device is configured to determine a route to take on the transport infrastructure for a user based on historical routes taken on the transport infrastructure by that user, or by other users for example from crowdsourced data.

In some examples the remote control is configured to communicate with a user’s mobile device and to provide a notification to the user’s device in the event that the determined air quality measurement falls below a selected threshold.

In another aspect there is provided a remote control for an air purifier. The remote control comprises an air quality sensor, and the remote control is configured to communicate wirelessly with the air purifier to control operation of the air purifier based on at least one of:

In another aspect there is provided a computer-implemented air quality monitoring system. The computer-implemented air quality monitoring system is configured to receive and aggregate a plurality of air quality measurements from a plurality of portable air quality sensors as a function of time and position, map the air quality measurements to a transport infrastructure, and determine a route to take on the transport infrastructure based on the air quality measurements. For example, the system may be configured to determine a route to take on the transport infrastructure based on historical routes taken on the transport infrastructure by the user and/or other users, for example via crowdsourced data.

In another aspect there is provided a method of monitoring air quality. The method comprises receiving and aggregating a plurality of air quality measurements from a plurality of portable air quality sensors as a function of time and position, mapping the air quality measurements to a transport infrastructure, and determining a route to take on the transport infrastructure based on the air quality measurements. For example, determining a route to take on the transport infrastructure may comprise determining a route to take on the transport infrastructure based on historical routes taken on the transport infrastructure by the user and/or other users, for example via crowdsourced data.

Drawings

Embodiments of the disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which:

Fig. 1 shows a perspective rendered view of an example air purifier;

Fig. 2 shows a perspective rendered view of the example air purifier of Fig. 1 with the housing made transparent to show some of the internal features of the air purifier;

Fig. 3 shows a perspective rendered cross-section through the air purifier of Figs. 1 and 2;

-7Fig. 4 shows a wireframe drawing of selected features of the air purifier of Figs. 1 to 3; Fig. 5 shows a perspective rendered cross-section through the features shown in Fig. 4; Fig. 6 shows the perspective view of Fig. 2 but zoomed in on selected features of the air purifier shown in Figs. 1 to 5;

Fig.7 shows a wireframe version of Fig. 2;

Fig. 8 shows a schematic cross-section of a remote control for use an air purifier such as with the air purifier of Figs. 1 to 7;

Fig. 9 shows a schematic view of a remote device for use with an air purification system, for example comprising the air purifier of Figs. 1 to 7 and/or the remote device of Fig. 8;

Fig. 10 shows an example flow chart for a method of monitoring air quality;

Fig. 11 shows a perspective zoomed in view of selected features of the air purifier shown in Figs. 1 to 7; and

Fig. 11 shows a perspective zoomed in view of selected features of the air purifier shown in Figs. 1 to 7 and 11.

Specific description

Embodiments of the claims relate to an air purifier, a remote control for an air purifier, an air purification system, a computer-implemented air quality monitoring system and a method of monitoring air quality.

Fig. 1 shows an example air purifier 100 of embodiments of the disclosure. Aspects of the air purifier 100 shown in Fig. 1 are also shown in more detail in Figs. 2 to 7. Like reference numbers have been used to denote similar or the same features with similar or the same functionality.

The air purifier 100 shown in Fig. 1 has an elongate tubular housing comprising an air inlet 10 and a first air outlet 12. As such, the air purifier 100 has a longitudinal axis L formed by the elongate tubular housing generally corresponding to an airflow direction in a direction going from the air inlet 10 to the first air outlet 12. In the example shown in Fig. 1, the air inlet 10 is proximal to one end of the housing, and the first air outlet 12 is proximal to the other end of the housing. The air purifier 100 also comprises an optional second air outlet 14 on one side of the housing. The optional second air outlet 14 is between the air inlet 10 and the first air outlet 12 along the longitudinal axis L and has a

-8smaller cross-sectional area than the first air outlet 12.

Fig. 2 shows the air purifier 100 of Fig. 1 but with the housing made transparent so that the internal workings of the air purifier 100 can be seen. Fig. 2 also shows an optional remote control 200 coupled to the top of the air purifier 100 (the remote control 200 is described in more detail below with reference to Fig. 8). Fig. 3 shows a cross-section through the air purifier 100 shown in Fig. 1. The air purifier 100 may have a magnetic coupling for removeably coupling the remote control 200 magnetically to the top of the air purifier 200.

As shown in Figs. 2 and 3, the air purifier 100 comprises a photocatalytic reactor 40, a fan 30, a UV light source 20 and an optional filter 25. The fan 30 is located between the filter 25 and the photocatalytic reactor 40 along the longitudinal axis L. The optional filter 25 may be removable and washable, and is located between the air inlet 10 and the fan 30 in the longitudinal axis. The filter 25 may be, for example, manufactured from a nonwoven fabric.

In the example shown in Fig. 2 the UV light source 20 is located at the bottom of the photocatalytic reactor 40 in the air flow direction, although of course it will be appreciated that the UV light source 20 could be located elsewhere. As shown in Figs. 4 and 6 described below, the UV light source 20 in the example shown comprises a plurality of (in this example, four) UV LEDs spaced at intervals around a ring 22 inside the housing. The ring 22 is shaped to allow the passage of air through the ring 22 and onto the photocatalytic reactor 40. As shown in more detail in Fig. 12, the UV LEDs 20 are coupled to the ring 22 via arms 23 that project inwardly towards the centre of the ring 22 and are arranged to direct light upwards in the air flow direction, and in the example shown, parallel to the longitudinal axis L of the housing. By coupling the UV LEDs 20 to the ring 22 in this manner the UV LEDs 20 can be better directed onto a larger surface area of the photocatalytic reactor 40.

As can be seen in the example shown in Fig. 12 (and as described in more detail below), the ring 22 is not circular but is instead elliptical so as to provide a region with a larger area for coupling to and supporting the power interface 23, processor and a “break-off”

-9printed circuit board (PCB) 60 mounted transverse to the ring 22 and parallel to the longitudinal axis L, comprising first air quality sensor 62. The arms 23 vary in length such that each UV LED 20 is at the same distance radially from the centre of the housing. However, it will of course be understood that other arrangements of the UV light source 20 could be envisaged.

The photocatalytic reactor 40 is better shown in Figs. 4 and 5. Figs. 4 and 5 show the air purifier 100 of Figs. 1 to 3 but with some features removed to better highlight the structure of the photocatalytic reactor 40. In the example shown, the photocatalytic reactor 40 is shaped to rotate air flowing in the air flow direction in at least a part-circular motion relative to the longitudinal axis L and comprises two photocatalytic reactor plates transverse to each other along the airflow direction.

In this example the photocatalytic reactor 40 forms at least a part-turn of a helix, although it will be understood that in other examples the photocatalytic reactor 40 may be shaped in other ways to deflect air relative to the longitudinal axis L. For example, the photocatalytic reactor 40 may comprise a series of plates or baffles arranged to deflect and mix the air flowing in the airflow direction along the longitudinal axis L.

In the examples shown the photocatalytic reactor 40 is porous, and comprises an open cell material, which in this example is a polyurethane foam. The photocatalytic reactor 40 is also coated in a thin layer (for example, less than 1 pm, for example less than 100 nm) of photocatalyst, which in this example is titanium dioxide, TiO2.

Figs. 4 and 5 also show optional power interface 23 (shown in more detail in Fig. 12 described below). The power interface 23 is for powering the fan 30 and the USB light source 20 (as well as any other components of the air purifier 100 that may require power such as a processor, sensor 62, the wireless communications interface and visual indicator 69 described below), and may comprise, for example, a USB-C interface.

Also shown are optional honeycomb mesh 27 and processor. The optional honeycomb mesh 27 is located between the filter 25 and the fan 30, and may serve as a support for the filter 25 and also serve to protect the fan 30 from the filter 25, for example if the filter

- IQ25 is removed and replaced for cleaning (for example washing) by a user. The processor is coupled to the fan 30 and the UV light source 20 and is configured to control operation of the fan 30 and UV light source 20. The processor may also be coupled to or comprise a wireless communications interface, such as a WiFi® and/or a BlueTooth® interface, for communication with a remote control 200 (or a plurality of remote controls 200) and/or a remote device 800 and/or a user’s mobile device.

The fan 30 is configured to direct air through the elongate tubular housing from the air inlet 10 to the air outlet 12 and via the photocatalytic reactor 40 in the air flow direction. The fan 30 may also direct air optionally via the filter 25 (for example by drawing air through the filter 25) before it passes through the photocatalytic reactor 40 in the airflow direction. As such the filter 25 is configured to allow the passage of air therethrough. In the example shown, the air flow direction is parallel to the longitudinal axis L of the elongate tubular housing. The photocatalytic reactor 40 is slanted to deflect, obliquely to the longitudinal axis, air flowing in the air flow direction from the air inlet 10 to the first air outlet 12. By providing an air purifier 100 that deflects air flowing through the air purifier 100 in this way, the air may be better mixed, therefore providing an increased production of hydroxyl radicals and additional an increased neutralisation of compounds such as VOCs.

The arrangement of the UV light source 20 and the photocatalytic reactor 40 is shown in closer detail in Fig. 6. As can be seen in Fig. 6, the UV light source 20 is configured to direct UV light onto the photocatalytic reactor 40. In the example shown, by virtue of the arrangement of the UV light source 20 with respect to the photocatalytic reactor 40, and by virtue of the arrangement of the shape of the photocatalytic reactor 40 itself, the UV light source 20 is configured to direct light obliquely onto the photocatalytic reactor 40. By directing light obliquely onto the photocatalytic reactor 40 in this manner, a greater surface area of the photocatalytic reactor 40 may be exposed to the UV light. This in turn may lead to an increased production of hydroxyl radicals and an increased neutralisation of compounds such as VOCs, and thereby an increased air purifying efficacy of the air purifier 100.

In some examples the air purifier 100 further comprises a first air quality sensor 62

-11 exterior to the housing and a second air quality sensor proximal to the first air outlet 12 (described in more detail below with reference to Fig. 12). For example, the first air quality sensor 62 may be coupled to the processor, for example located approximately mid-way along the housing between the air inlet 10 and the first air outlet 12. The second air quality sensor may be located on the top of the air purifier 100, near the first air outlet 12. In examples where the air purifier 100 comprises a remote control 200, the remote control 200 may comprise the second air quality sensor 807.

In such examples the processor may be configured to (i) receive signals from the first and second air quality sensors (for example via a wireless communications interface coupled to the processor) and (ii) make a determination of the air purifying efficacy of the air purifier 100. In such examples the processor may be configured to control the speed of the fan 30 based on the determination of the air purifying efficacy of the air purifier 100. Of course it will be understood that in other examples a different processor (such as a processor of the remote control 200 or a remote device 800) may be configured to make this determination based on signals received from the first and second air quality sensors.

For example, at least one of the first 62 and second 807 air quality sensors may comprise at least one of a CO (carbon monoxide) sensor, a VOC (volatile organic compound) sensor. For example, the first air quality sensor 62 may comprise at least one of a CO (carbon monoxide) sensor and a VOC (volatile organic compound) sensor, and the second air quality sensor 807 in the remote control 200 may comprise at least one of a VOC sensor, CO sensor, light brightness lux sensor, light colour sensor, temperature sensor, humidity sensor and pressure sensor. In some examples the first air quality sensor 62 and/or the second air quality sensor 807 may comprise a plurality of sensors.

The carbon monoxide sensor may comprise a high-performance screen printed electrochemical sensor, although it will be appreciated that there are other types of sensors that can perform the same function. Each of the sensors is individually calibrated and measures from 0 to 500PPM (parts per million), there are other sensors that go up to 1000PPM and greater.

-12 The VOC sensor may be compliant with ISO16000-29 (“Test methods for VOC detectors”). It produces raw resistance values.

Indoor air quality (IAQ) may be determined based on signals received from the first 62 and second 807 air quality sensors. For example, IAQ may be determined based on signals received from CO and VOC sensors. Based on an intelligent algorithm, software provides an indoor air quality (IAQ) output from the raw readings of the sensors 62, 807. This output is in an index that can have values ranging from 0 to 500 with a resolution of 1 to indicate or quantify the quality of the air available in the surrounding.

For example, the index may be:

• Good 0-50 • Moderate 51-100 • Unhealthy for Sensitive Groups 101-150 • Unhealthy 151-200 • Very Unhealthy 201-300 • Hazardous 301-500

In order to determine the effectiveness of the filtration methods readings will be taken from both the first and second air quality sensors 62, 807, for example two CO sensors. The difference between measurements received from the two sensors will be compared in terms of a percentage. This percentage difference will slot into certain performance thresholds in order to determine the effectiveness. This will allow us to, monitor the performance of the filter and also allow us provide a result that can help the user understand how much cleaner the air going out the outlet is compared the inlet. In other purification devices that use HEPA and other means of filtration it can help to determine when filters need to be replaced.

As noted above, in some examples the air purifier 100 comprises an optional second air outlet 14. In such examples the first air outlet 12 may be configured to direct air away from the air purifier 100 in the same direction as the longitudinal axis, and the second air outlet 14 is configured to direct air sideways away from the air purifier 100 in a direction

-13transverse to the longitudinal axis. In such examples the air purifier 100 may be operable to direct air away from the air purifier 100 via either the first air outlet 12 or the second air outlet 14.

The second air outlet 14 may have a smaller cross-sectional area than the first air outlet 12 such that air directed through the second air outlet 14 travels at a greater speed than air directed through the first air outlet 12.

In some examples the air purifier 100 may further comprise a selector 90 coupled to the air purifier 100 and configured to block at least one of the first air outlet 12 and the second air outlet 14. The selector 90 may be operable to vary the degree to which the first air outlet 12 and the second air outlet 14 are blocked by the selector 90, for example, between (a) a first configuration where the first air outlet 12 is open and the selector 90 blocks the second air outlet 14, and (b) a second configuration where the selector 90 blocks the first air outlet 12 and the second air outlet is open 14. For example, the selector 90 may be operable to partially block both the first air outlet 12 and the second outlet 14.

Figs. 7 and 11 show the air purifier 100 of Figs. 1 to 6 highlighting the functionality of the selector 90. In the example shown in Fig. 7, the selector 90 is coupled to the both the first air outlet 12 and the second air outlet 14. The first air outlet 12 comprises a series of alternating apertures for the passage of air therethrough. The apertures are tessellated, in other words they are repeating. The selector 90 comprises a first plate 91 having a complementary set of apertures, such that in one configuration the apertures of both the first air outlet 12 and the selector 90 align to allow the passage of air therethrough, but in a second configuration the first plate 91 of the selector 90 blocks the apertures of the first air outlet 12 such that the passage of air therethrough is inhibited. The second air outlet 14 also comprises a series of apertures. The selector 90 comprises a second plate 92 that can slide across the apertures of the second air outlet 14 to block or partially block the apertures of the second air outlet 14. The first plate 91 of the selector 90 for the first air outlet 12 is coupled to the second plate 92 of the selector 90 for the second air outlet 14 such that the two plates 91, 92 move at the same time.

- 14In the example shown, the selector 90 is operable by rotating a portion of the end of the housing of the air purifier 100. Rotating the portion of the end of the housing of the air purifier 100 causes the two plates to move, blocking either the first air outlet 12 or the second air outlet 14, or partially blocking both air outlets 12, 14. In this way, the directionality of air output from the air purifier 100 can be controlled based on the user’s preference, for example to provide a local purifying mode if the user is sitting next to the air purifier 100 (for example air may be directed into their face via the second air outlet 14) or a room-wide purifying mode (for example by directing air via the first air outlet 12) as desired.

As shown in Figs. 2 and 3, in some examples the air purifier 100 may comprise a remote control 200. In such examples the air purifier 100 and the remote control 200 may be part of an air purification system. An example schematic view of a remote control 200 is shown in Fig. 8.

The remote control 200 is a detachable component that is designed to be carried around by a user and thereby could be considered as a “wearable” device. The remote control 200 has a self-contained source of power 801, such as a battery or capacitive power source, and can recharge wirelessly by placing it on top of the air purifier 100. For example, the remote control 200 comprises a battery 801 coupled to a wireless charging interface 803. In some examples the air purifier 100 comprises a wireless charging interface 75 configured to couple with the wireless charging interface 803 of the remote control 200 for charging the battery 801 of the remote control 200. The wireless charging interface 803 of the remote control 200 may be a coil configured to couple and interact with the wireless charging interface 75 of the air purifier 100, for example the wireless charging interface 75 of the air purifier 100 may be configured to inductively charge the battery of the remote control 200. The remote control 200 may also comprise means to detachably secure the remote control 200 to the air purifier 100, such as one or more magnets.

In the example shown in Fig. 8, the remote control 200 comprises a battery 801 coupled to a wireless charging interface 803. It also comprises a processor 805 coupled to a means for identifying its location 815, such as a GPS chip, a sensor 807 and a wireless

-15communications interface 819. The processor 805 is coupled to both the battery 801 and a display 809, which in this example is an LCD display bonded to glass which provides the top surface of the remote control 200. The processor 805 is also coupled to a button 817 on the side of the remote control 200. Coupled to the remote control is a lanyard 813. The sensor 807 is an air quality sensor, such as the second air quality sensor mentioned above. It may also comprise other sensors, such as an air pressure sensor, a temperature sensor, a humidity sensor and a carbon monoxide sensor, a light (lux) sensor and a colour sensor. One or more of the sensors may be integrated into the same chip.

The remote control also comprises air vents 811 that are configured to allow the passage of air to flow into the remote control 200 such that the sensor 807 can take measurements on the incoming air. The display 809 is configured to display, amongst other things, air quality information. It may also be configured to display information such as temperature, humidity, efficiency of the coupled air purifier 100, fan speed etc. The processor 805 is configured to make a determination based on signals received from the sensor 807 and display the results of these determinations to the user. The button 817 is configured to power on/off the display and/or the remote control 200. The wireless communications interface 819, may be, for example a BlueTooth® interface, and is configured to communicate with an air purifier 100 and/or a user’s mobile device.

In some examples, the remote control 200 is configured to communicate wirelessly with the air purifier 100 (or a plurality of air purifiers 100), for example with the processor of the air purifier 100. The remote control 200 may be configured to communicate wirelessly, for example via Bluetooth®, with the air purifier 100. The remote control 200 may be configured to communicate with the processor of the air purifier 100 to control the speed of the fan 30 of the air purifier 100 based on at least one of: (i) an air quality measurement determined based on signals received from the air quality sensor of the remote control 200; and (ii) the proximity of the remote control 200 (or a remote control 200 from a selected group of remote controls 200) to the air purifier 100. It will of course be appreciated that a number of remote controls 200 may communicate with the same air purifier 100.

-16The remote control 200 may be configured to record air quality measurements (as well as other measurements such as light intensity (lux), colour, humidity, temperature etc. as a function of time and location. For example, the remote control 200 may be configured to be a wearable device, for example it may be configured to be carried around by a user, for example, on a lanyard 813 in a manner similar to a FitBit®. The remote control 200 may be configured to keep a record of the air quality experienced by the user throughout the day, and may, for example, provide a report at the end of the day/week/month as appropriate.

For example, the remote control 200 and/or an air purification system comprising the remote control 200 may be configured to communicate with a remote device 800 that aggregates air quality measurements from a plurality of locations as a function of time. The remote device 800 may map the air quality measurements to a transport infrastructure, and determine a route to take on the transport infrastructure based on the air quality measurements. For example, the remote device 800 may be configured to determine a route to take on the transport infrastructure for a user based on historical routes taken on the transport infrastructure by that user. In another example, if a user normally walks or cycles to work along a particular route on the transport infrastructure, based on aggregated air quality data, the remote device 800 may determine an alternative route to take that is less polluted. The aggregated air quality data may include data obtained from other users (i.e. “crowdsourced” data).

In some examples the remote control 200 is configured to communicate with a user’s mobile device (for example with a bespoke application on the mobile device). For example, the remote control 200 may be configured to provide a notification to the user’s device in the event that the determined air quality measurement falls below a selected threshold. For example, if the user is in a polluted environment, the remote control 200 may make a determination that the air quality is below a selected threshold and in response to determining that the air quality is below a selected threshold, send a notification to the mobile device. The notification may comprise an action to take, for example to leave the polluted area or to open a window.

Fig. 9 shows an example remote device 900 that may be used as part of an air

-17purification system, or that may communicate with remote control 200 as described above. The remote device 900 comprises a wireless interface 902 coupled to a processor 904 that is also coupled to a data store 906. The wireless interface 902 may be configured to communicate with the remote control 200.

The processor 904 may be programmed with instructions that mean, when executed, the remote device 900 can receive and aggregate a plurality of air quality measurements from a plurality of portable air quality sensors (such as from remote control 200 as described above) as a function of time and position, map the air quality measurements to a transport infrastructure, and determine a route to take on the transport infrastructure based on the air quality measurements.

Also described herein is a method of monitoring air quality. Fig. 10 shows an example method of monitoring air quality 1000. The method of monitoring air quality 1000 comprises receiving 1001 and aggregating a plurality of air quality measurements from a plurality of portable air quality sensors as a function of time and position, mapping 1003 the air quality measurements to a transport infrastructure, and determining 1005 a route to take on the transport infrastructure based on the air quality measurements.

Fig. 12 shows the details of the processor and power interface 23 in closer detail. As can be seen in Fig. 12, the power interface is a USB-C interface and is coupled to processor. The processor is also coupled to the first air quality sensor 62 and a button 64. It will of course be understood that the processor may be coupled to other sensors as well. The power interface 23, processor and button 64 are mounted on the ring 22 that supports the UV LEDs 20. As such and as described above, the ring 22 is elliptical in shape to provide a larger area for the power interface 23 and button 64 to be mounted on. Also mounted on the ring 22 is the “break-off’ printed circuit board (PCB) 60, comprising the first air quality sensor 62. The “break-off’ PCB 60 is mounted transverse to the ring 22 and parallel to the longitudinal axis L of the elongate housing against the wall of the elongate housing. The “break-off’ PCB 60 board slots into the purifier’s housing behind an aperture in the elongate housing covered with a layer of fabric and a logo. This may stop the first air quality sensor 62 from sensing internal filtered air - only allowing it to sense air outside of the purifier 100 which in the examples shown may be

-18done through the open back logo and fabric.

The button 64 is configured to control operation of the air purifier 100. For example, by operating the button 64 the operator may be able to power on the air purifier 100. The air purifier 100 may be configured to operate in different modes of operation, for example five modes of operation. Each mode of operation may involve the fan 30 operating at a different speed. Further presses of the button 64 may cycle the air purifier 100 through the different modes of operation. To provide an indication to the user of which mode of operation the air purifier 100 is operating in, the air purifier 100 also comprises a visual indicator 69 adjacent to the power interface 23 (shown more clearly in Fig. 1). In the example shown the visual indicator 69 is a series of five LEDs that are lit depending on the mode of operation.

The air purifier 100 and/or remote control 200 may be manufactured by way of ‘3D printing’ whereby a three-dimensional model of the air purifier 100/remote control 200, or any component thereof, are supplied, in machine readable form, to a ‘3D printer’ adapted to manufacture the air purifier 100/remote control 200, or any component thereof. This may be by additive means such as extrusion deposition, Electron Beam Freeform Fabrication (EBF), granular materials binding, lamination, photopolymerization, or stereolithography or a combination thereof. The machine readable model comprises a spatial map of the object to be printed, typically in the form of a Cartesian coordinate system defining the object’s surfaces. This spatial map may comprise a computer file which may be provided in any one of a number of file conventions. One example of a file convention is a STL (STereoLithography) file which may be in the form of ASCII (American Standard Code for Information Interchange) or binary and specifies areas by way of triangulated surfaces with defined normals and vertices. An alternative file format is AMF (Additive Manufacturing File) which provides the facility to specify the material and texture of each surface as well as allowing for curved triangulated surfaces. The mapping of the air purifier 100/remote control 200, or any component thereof may then be converted into instructions to be executed by 3D printer according to the printing method being used. This may comprise splitting the model into slices (for example, each slice corresponding to an x-y plane, with successive layers building the z dimension) and encoding each slice into a series of instructions. The instructions sent to the 3D printer

-19may comprise Numerical Control (NC) or Computer NC (CNC) instructions, preferably in the form of G-code (also called RS-274), which comprises a series of instructions regarding how the 3D printer should act. The instructions vary depending on the type of 3D printer being used, but in the example of a moving printhead the instructions include:

how the printhead should move, when/where to deposit material, the type of material to be deposited, and the flow rate of the deposited material.

In the context of the present disclosure other examples and variations of the apparatus and methods described herein will be apparent to a person of skill in the art.

Claims

CLAIMS:

1. An air purifier, comprising:

an elongate housing comprising an air inlet and an air outlet, wherein the elongate housing has a longitudinal axis;

a photocatalytic reactor;

a fan configured to direct air through the elongate housing from the air inlet to the air outlet via the photocatalytic reactor in an air flow direction;

a UV light source configured to direct UV light onto the photocatalytic reactor; and wherein the photocatalytic reactor is slanted to deflect, obliquely to the longitudinal axis, air flowing in the airflow direction from the air inlet to the air outlet.

2. The air purifier of claim 1 wherein the UV light source is configured to direct light obliquely onto the photocatalytic reactor.

3. The air purifier of claim 1 or 2 wherein the photocatalytic reactor is shaped to rotate air flowing in the air flow direction in at least a part-circular motion relative to the longitudinal axis.

4. The air purifier of any of the previous claims wherein the photocatalytic reactor forms at least a part-turn of a helix.

5. The air purifier of any of the previous claims wherein the photocatalytic reactor comprises at least two photocatalytic reactor plates transverse to each other along the airflow direction.

6. The air purifier of any of the previous claims further comprising a filter comprising a non-woven fabric between the air inlet and the fan, wherein the filter is configured to allow the passage of air therethrough.

7. The air purifier of any of the previous claims wherein the photocatalytic reactor is porous.

8. The air purifier of any of the previous claims wherein the photocatalytic reactor comprises an open cell material.

9. The air purifier of any of the previous claims further comprising a first air quality sensor exterior to the air purification system and a second air quality sensor proximal to the air outlet, and wherein the air purification system comprises a processor configured to (i) receive signals from the first and second air quality sensors and (ii) make a determination of the air purifying efficacy of the air purifier.

10. A photocatalytic air purifier comprising:

an air inlet and an air outlet;

a first air quality sensor exterior to the air purifier; and a second air quality sensor proximal to the air outlet;

wherein the air purifier comprises a processor configured to (i) receive signals from the first and second air quality sensors and (ii) make a determination of the air purifying efficacy of the air purifier.

11. The air purifier of claim 10 further comprising a fan configured to direct air from the air inlet to the air outlet via a photocatalytic reactor in an air flow direction.

12. The air purifier of claim 9 or 11 wherein the processor is configured to control the speed of the fan based on the determination of the air purifying efficacy of the air purifier.

13. The air purifier of any of the previous claims, wherein the air outlet comprises a first air outlet for directing air away from the air purifier in the same direction as the longitudinal axis, and a second air outlet for direction air away from the air purifier in a direction transverse to the longitudinal axis, and wherein the air purifier is operable to direct air away from the air purifier via either the first air outlet or the second air outlet.

14. A photocatalytic air purifier comprising:

a fan configured to direct air from the air inlet to the air outlet via a photocatalytic

-22 reactor in an airflow direction; and wherein the air outlet comprises a first air outlet for directing air away from the air purifier in the same direction as the longitudinal axis, and a second air outlet for directing air away from the air purifier in a direction transverse to the longitudinal axis, and wherein the air purifier is operable to direct air away from the air purifier via either the first air outlet or the second air outlet.

15. The air purifier of claim 13 or 14 wherein the second air outlet has a smaller cross-sectional area than the first air outlet such that air directed through the second air outlet travels at a greater speed than air directed through the first air outlet.

16. The air purifier of any of claims 13 to 15 wherein the air purifier further comprises a selector coupled to the air purifier and configured to block at least one of the first air outlet and the second air outlet, wherein the selector is operable to vary the degree to which the first air outlet and the second air outlet are blocked by the selector between (a) a first configuration where the first air outlet is open and the selector blocks the second air outlet, and (b) a second configuration where the selector blocks the first air outlet and the second air outlet is open.

17. An air purification system comprising the air purifier of any of the previous claims, and a remote control, wherein the remote control comprises an air quality sensor, and wherein the remote control is configured to communicate wirelessly with the air purifier to control the speed of the fan of the air purifier based on at least one of:

18. An air purification system comprising a photocatalytic air purifier and a remote control, wherein the air purifier comprises:

an air inlet and an air outlet;

a fan configured to direct air from the air inlet to the air outlet via a photocatalytic reactor in an airflow direction along a longitudinal axis; and wherein the remote control comprises an air quality sensor and a wireless

-23interface for communicating with the air purifier;

wherein the air purifier comprises a wireless communications interface for communicating with the remote control, and a processor coupled to the wireless communications interface and to the fan, wherein the processor is configured to receive signals from the air quality sensor of the remote control and to control the speed of the fan based on at least one of:

19. The air purification system of claim 17 or 18, wherein the air purifier comprises a wireless charging interface, and wherein the remote control also comprises a wireless charging interface configured to couple with the wireless charging interface of the air purifier for charging a battery of the remote control.

20. The air purification system of any of claims 17 to 19 wherein the remote control is configured to record air quality measurements as a function of time and location, and wherein the air purification system is configured to communicate with a remote device that aggregates air quality measurements from a plurality of locations as a function of time, and map the air quality measurements to a transport infrastructure, and wherein the remote device is configured to determine a route to take on the transport infrastructure based on the air quality measurements.

21. The air purification system of claim 20 wherein the remote device is configured to determine a route to take on the transport infrastructure for a user based on historical routes taken on the transport infrastructure by that user.

22. The air purification system of any of claims 17 to 21 wherein the remote control is configured to communicate with a user’s mobile device and to provide a notification to the user’s device in the event that the determined air quality measurement falls below a selected threshold.

23. A remote control for an air purifier, wherein the remote control comprises an air

-24quality sensor, and wherein the remote control is configured to communicate wirelessly with the air purifier to control operation of the air purifier based on at least one of:

24. A computer-implemented air quality monitoring system, where the system is configured to:

receive and aggregate a plurality of air quality measurements from a plurality of portable air quality sensors as a function of time and position;

map the air quality measurements to a transport infrastructure; and determine a route to take on the transport infrastructure based on the air quality measurements.

25. A method of monitoring air quality, comprising:

receiving and aggregating a plurality of air quality measurements from a plurality of portable air quality sensors as a function of time and position;

mapping the air quality measurements to a transport infrastructure; and determining a route to take on the transport infrastructure based on the air quality measurements.