WO2023026032A1

WO2023026032A1 - An air treatment device

Info

Publication number: WO2023026032A1
Application number: PCT/GB2022/052163
Authority: WO
Inventors: Aleksander MOCZEK
Original assignee: Equipmake Limited
Priority date: 2021-08-23
Filing date: 2022-08-22
Publication date: 2023-03-02
Also published as: GB202112059D0; GB2611866A; GB202212158D0

Abstract

An air treatment device (10) comprises an air inlet (14), an air outlet (16), a conduit (12) defining an air flow path between the air inlet and the air outlet, and a source (18) of infrared radiation in the conduit, wherein the infrared radiation source is configured to emit radiation having a wavelength in the range 820nm to 900μm. An air treatment device including a chamber (38) and a source (40) of microwave radiation for emitting microwaves into the chamber is also provided.

Description

Title: An air treatment device

Field of the disclosure

The present disclosure relates to an air treatment device and more particularly to such a device which is suitable for installation in a vehicle.

Background to the disclosure

There is increasing awareness of the need to treat air supplied to enclosed spaces within vehicles or buildings following the Covid- 19 pandemic. It may be desirable to treat air drawn from the ambient atmosphere, and there is a greater demand to be able to treat air which is recirculated within a vehicle or building. Recirculation allows warmed or cooled air to be retained and thereby reduce the amount of energy consumed in controlling the internal temperature. However, there is a risk that recirculated air may carry bacteria or viruses exhaled by passengers or building users.

Summary of the disclosure

The present disclosure provides an air treatment device comprising: an air inlet; an air outlet; a conduit defining an air flow path between the air inlet and the air outlet; and a source of infrared radiation in the conduit, wherein the infrared radiation source is configured to emit radiation having a wavelength in the range 820nm to 900pm.

Preferably, the infrared radiation source is configured to emit short-wave infrared radiation having a wavelength in the range 2 to 3.5pm. Radiation in this range has been found to interact particularly strongly with water in particles in the air, such as bacteria and viruses, through absorption of the microwaves by the water, whilst minimising heating of the air. The selected wavelength may be around 3 pm for example. In some preferred examples, the infrared radiation source is configured to emit radiation having a wavelength in the range 820 to 1200nm, or 900 to HOOnm, and more preferably around lOOOnm.

It has been found that infrared radiation having a wavelength in the range 820 to 1200nm is effective to dry and kill bacteria and viruses in an air flow. There may be minimal transfer of heat energy to the air flow, which may be particularly beneficial when feeding the air into a temperature-controlled environment.

In further implementations, the infrared radiation source may be configured to emit radiation having a wavelength in the range 700 to 900pm, or 750 to 850pm, and more preferably around 800pm.

Preferably, a reflector is carried by the conduit (or an inwardly facing surface of the conduit may be reflective) for reflecting infrared radiation from the infrared radiation source back towards the interior of the conduit. This serves increase the intensity of the radiation in the conduit for a given power consumption.

In a preferred implementation, the conduit is tubular. The conduit may define a flow path for air passing through the device.

The infrared radiation source may be elongate and extend longitudinally along the conduit. Air flowing through the device may therefore be exposed to the infrared radiation along the length of the source, increasing the likelihood of any bacteria or viruses in the air flow receiving sufficient radiation to kill them.

The conduit may include a chamber, and a source of microwave radiation for emitting microwaves into the chamber. Accordingly, the air flow may be treated using both infrared and microwave radiation, which in combination enhance the ability of the device to disinfect air flowing through the device. In some preferred configurations, the microwave chamber is downstream of the source of infrared radiation. The heating effect of the microwaves is concentrated on any bacteria or virus particles in the air flow that still hold water so as to dry them further.

The present disclosure further provides an air treatment device comprising: an air inlet; an air outlet; a conduit defining an air flow path between the air inlet and the air outlet, wherein the conduit includes a chamber; and a source of microwave radiation for emitting microwaves into the chamber.

The microwaves act to heat up water in viruses and/or bacteria carried by the air flow passing through the device and thereby kill them.

The microwave radiation source may emit microwaves having a frequency in the range of 2 to 4 GHz, for example, and preferably around 2.54GHz.

The air flow path may extend longitudinally through the chamber, with the chamber including a plurality of (preferably planar) microwave reflective surfaces which are disposed circumferentially around the air flow path, the microwave radiation source arranged to emit microwaves transversely into the chamber, and the reflective surfaces arranged to reflect the microwaves transversely across the chamber. As a result, the microwaves are transmitted across the chamber multiple times to enhance the effectiveness of the device. The reflective surfaces may be arranged to reflect the microwaves sequentially from one microwave reflective surface to the next, so as to define a path for the microwaves which is incident on all of the reflective surfaces.

The chamber may include a cylindrical wall having a diameter corresponding to half (or around half) of the wavelength of the microwave radiation, or a whole number multiple thereof, in examples where the microwaves are reflected across the chamber by the walls of the chamber itself. For example, the radius of the chamber may correspond to the wavelength of the microwaves. The distance from each microwave reflective surface to the next along the defined path for the microwaves may correspond to half (or around half) of the wavelength of the microwave radiation, or a whole number multiple thereof. For example, this distance may correspond to the wavelength of the microwaves.

Calibration of the chamber configuration to set accurately the length of each transit across the chamber by the microwaves (with reference to their wavelength as referred to above) is advantageous to enhance the effectiveness of the device, as the reflected waves will tend to interfere constructively rather than cancel each other.

The present disclosure also provides a vehicle including a device as disclosed herein for treating air flowing to an interior passenger space of the vehicle.

Brief description of the drawings

Examples of the present disclosure will now be described by way of example with reference to the accompanying drawings, wherein:

Figure 1 shows a schematic cross-sectional side view of an infrared-based air treatment device according to an example of the present disclosure;

Figure 2 shows a perspective view of a micro wave-based air treatment device according to an example of the present disclosure; and

Figure 3 shows a transverse cross-sectional view of the device shown in Figure 2.

Detailed description

Figure 1 is a cross-sectional view of an air treatment device 10 according to one implementation of the present disclosure. It includes an air conduit 12 having an inlet 14 at one end and an outlet 16 at its opposite end. The conduit may have a diameter of around 100mm. An infrared radiation source 18 is located in the conduit. The source may comprise a carbon fibre heating element, for example. The radiation source may be configured to emit radiation having a wavelength in the range 2 to 3.5pm, and preferably around 3 pm.

The heating element may be elongate and extend longitudinally along the conduit. The conduit 12 may have a tubular configuration. The heating element may be spaced from the walls of the conduit. The heating element may extend along a central axis of the conduit.

A reflective surface may surround the heating element. For example, a reflector 20 may be carried by the inner surface of the conduit to reflect radiation emitted by the infrared source back towards the interior of the conduit. The reflector may provide a mirrored surface.

The power rating of the infrared radiation source may be selected having regard to the expected flow rate and humidity of air to pass through the device during its use. For example, a carbon fibre heating element having a power output of between 120W and 1200W may be appropriate for a device to be used in a passenger bus. It may be appropriate to supply around 10 litres/min per passenger in such a vehicle.

Figures 2 and 3 show an air treatment device 30 which uses microwave radiation according to a further aspect of the present disclosure.

The device 30 includes a conduit 32 having an air inlet 34 and an air outlet 36. Air entering the device in direction A (parallel to a central axis 37 of the device) flows longitudinally through the device along an air flow path to the air outlet 36 where it exits in direction B.

The conduit includes a chamber 38 having a magnetron 40 coupled thereto. The magnetron is arranged to generate microwave radiation and to transmit it into the chamber. The chamber includes a central cylindrical portion 42 arranged with its central longitudinal axis aligned with the central axis 37 of the device. The chamber also includes two frustoconical end portions 44 which extend between respective, opposite ends of the cylindrical portion and the adjacent sections of the conduit 32 (and have their longitudinal central axes aligned with the central axis 37). The walls of the end portions 44 may subtend an angle of around 45° with the central axis of the device.

The radius of the chamber may correspond to half of the wavelength of the microwave radiation emitted by the magnetron, or a whole number multiple thereof. In one example, the microwave radiation has a frequency of 2.54 GHz, and the chamber has a radius equal to the wavelength of the radiation, that is 11.8cm. The axial length of the chamber may be equal to its radius. The radius of the chamber may be twice that of the conduit, for example.

Figure 3 illustrates how the chamber 38 is arranged to reflect microwave radiation emitted by the magnetron across the air flowing through the device 30. A plurality of planar microwave reflective surfaces are arranged circumferentially around the inner surface of the cylindrical portion 42.

Microwaves are emitted by the magnetron into the chamber along a transverse direction D. Those waves are then reflected by a reflective surface along another transverse direction which forms an angle with the direction of the waves received from the magnetron. The reflected waves then travel towards another reflective surface within the chamber to be reflected again towards a further reflective surface, causing the waves to travel across the body of the chamber multiple times, as illustrated in Figure 3.

The microwaves are reflected towards each reflective surface in turn, so that the path of the microwaves is incident on all of the reflective surfaces. The chamber may include sixteen planar reflective surfaces for example. The reflective surfaces may be provided by polished aluminium mirrors or by the surface of another metal.

The power consumption of the microwave device will depend on the humidity of the air flow. In relatively high humidity, such a device designed for use in a vehicle may consume around IkW. In lower humidity conditions, the power consumption may be reduced to about 200W.

In the present disclosure, the term “around” may mean +/-5% of the stated value.

Claims

8 Claims

1. An air treatment device comprising: an air inlet; an air outlet; a conduit defining an air flow path between the air inlet and the air outlet; and a source of infrared radiation in the conduit, wherein the infrared radiation source is configured to emit radiation having a wavelength in the range 820nm to 900pm.

2. A device of claim 1, wherein the infrared radiation source is configured to emit radiation having a wavelength in the range 2 to 3.5pm.

3. A device of claim 1, wherein the infrared radiation source is configured to emit radiation having a wavelength in the range 820 to 1200nm.

4. A device of claim 1, wherein the infrared radiation source is configured to emit radiation having a wavelength in the range 700 to 900pm.

5. A device of any preceding claim including a reflector carried by the conduit for reflecting infrared radiation from the infrared radiation source back towards the interior of the conduit.

6. A device of any preceding claim, wherein the conduit is tubular.

7. A device of any preceding claim wherein the infrared radiation source is elongate and extends longitudinally along the conduit.

8. A device of any preceding claim, wherein the infrared radiation source comprises a carbon fibre heating element.

9. A device of any preceding claim, wherein the conduit includes a chamber, and a source of microwave radiation for emitting microwaves into the chamber. 9

10. A device of claim 9, wherein the chamber is downstream of the source of infrared radiation.

11. An air treatment device comprising: an air inlet; an air outlet; a conduit defining an air flow path between the air inlet and the air outlet, wherein the conduit includes a chamber; and a source of microwave radiation for emitting microwaves into the chamber.

12. A device of any of claims 9 to 11, wherein the air flow path extends longitudinally through the chamber, the chamber includes a plurality of microwave reflective surfaces which are disposed circumferentially around the air flow path, and the microwave radiation source is arranged to emit microwaves transversely into the chamber, and the reflective surfaces are arranged to reflect the microwaves transversely across the chamber.

13. A device of claim 12, wherein the reflective surfaces are arranged to reflect the microwaves sequentially from one microwave reflective surface to the next, so as to define a path for the microwaves.

14. A device of claim 13, wherein the distance from each microwave reflective surface to the next along the defined path corresponds to half of the wavelength of the micro wave radiation, or a multiple thereof.

15. A device of any of claims 9 to 14, wherein the chamber includes a cylindrical wall having a diameter corresponding to half of the wavelength of the microwave radiation, or a multiple thereof.

16. A vehicle including a device of any preceding claim for treating air flowing to an interior passenger space of the vehicle.