FIELD OF THE INVENTION

The present invention relates to an air purification apparatus and in one aspect relates to an air purifier having a replaceable filter supporting a catalyst being activated by a UV light source.

BACKGROUND OF THE INVENTION

Catalytic air purifiers, which are used to treat a flow of air such as waste gases, are known or suggested in the published prior art. One type of conventional air purifier uses a UV lamp that acts on a catalyst to produce a photocatalytic reaction for treating organic material within a volume of air by way of oxidative degradation. This process of degradation produces non-hazardous substances such as water and carbon dioxide.

Typically, a UV light source and photo-catalyst, such as TiO?, are used, whereby the TiO? absorbs light thereby generating strong oxidizing agents, including hydroxyl radicals (-OH). The volatile organic compounds (VOC) and pathogens within the flow of air are broken down into water and carbon dioxide. Hydroxyl radicals are important in oxidative destruction of organic pollutants using a series of methodologies collectively known as advanced oxidation processes (AOPs). The destruction of pollutants in AOPs is based on the non-selective reaction of hydroxyl radicals on organic compounds.

One of the advantages with such photocatalytic reactions is that the free radicals typically produced, such as hydroxyl radicals, only last for a short time period, for instance a couple of milliseconds. This means that the reaction zone is contained within a limited area and reactive materials are not released into the environment, as occurs with some other air purifying devices.

In photocatalytic air purifiers, the catalyst is typically titanium dioxide (TiO?) which is irradiated by ultraviolet (UV) light. The titanium dioxide is typically applied as a thin film over a substrate, such as ceramic or metal.

One photocatalytic air treatment device is disclosed in International Patent Application No. PCT/AU2015/000533, in the name of Farmspec Pty Ltd, for an air modifying device configured to extend the shelf life of a fresh product and a method for use thereof. The device comprises a cylindrical hollow body including an inner surface coated with a metal oxide and a source of UV light within the body to direct UV light onto the surface. A fan is used to move air or gas through the hollow body.

One limitation with the Farmspec device, is that only a portion of the air is treated during use. Due to typical fluid flow dynamics through the cylindrical body the air flow at the centre of the tube will move faster than the air adjacent the inner side of the cylinder, on which the coating is applied. Although the laminar flow through the cylinder may be partly disrupted by eddies that form above the surface, typically the centre flow is not treated by the products of the photocatalytic reaction.

Another device is disclosed in U.S. Patent 6,336,998 (Wang) that is one form includes a cylindrical tube of glass-fibre cloth which is coated with TiO?, based on sol gel coating techniques. The impregnated cloth is however wrapped on the UV lamp tube and due to laminar flow, only part of the air is treated during use. Accordingly, the configuration of Wang would still allow potentially harmful matter to pass through the air cleaning or purifying device.

Many photocatalytic oxidation (PCO) air purifiers fail to completely decompose the VOCs in the air stream, which may result in the production of formaldehyde, acetaldehyde, formic acid and acetic acid.

Other air purification devices disclosed in the published prior art include U.S. Patent Application No. 2011/0033346 (Bohlen et al) and U.S. Patent Application No. 2010/0178199 (Schuman).

It should be appreciated that any discussion of the prior art throughout the specification is included solely for the purpose of providing a context for the present invention and should in no way be considered as an admission that such prior art was widely known or formed part of the common general knowledge in the field as it existed before the priority date of the application.

The reader will appreciate that although the term “purification” is used throughout the specification, it should be appreciated that the term encompasses the concept of treatment. For instance, the device could be used to treat a flow of air for the purposes of removing pollutants, chemicals including odours, or pathogens that may adversely affect stored products, such as, but not limited to fruit, vegetables or other foodstuffs. The reader should also appreciate that the device could be used for treating pathogens that may affect human health, such as in hospitals and school settings, or the device may be used in intensive agriculture applications, such as piggeries or poultry sheds, for the removal of harmful VOCs and organisms.

SUMMARY OF THE INVENTION

It is an object of the illustrated embodiments to provide for an air purification or treatment device that maximises contact between a flow of air and free radicals for oxidative degradation. It is a further object of the illustrated embodiments to overcome at least some of the aforementioned problems, or at least provide the public with a useful alternative. The foregoing objects should not necessarily be considered as cumulative and various aspects of the invention may fulfil one or more of the above objects.

In one aspect of the invention, but not necessarily the broadest or only aspect, there is proposed an air purification or treatment apparatus, comprising: a housing including an inlet adjoining an inlet compartment, and an outlet adjoining an outlet compartment; a UV light source positioned within or adjacent the outlet compartment; a filter cartridge including a first side positionable adjacent the inlet compartment and a second side positionable adjacent the outlet compartment, wherein the UV light source is configured to irradiate at least the second side of the filter cartridge; and a catalyst substance coating applied substantially at and adjacent the second side of the filter cartridge, whereby larger particulate matter within an inflow of air from the inlet compartment is capturable at or adjacent the first side of the filter cartridge, to thereby inhibit contamination or fouling of the catalyst substance coating by particulates in the air, at and adjacent the second side of the filter cartridge.

The filter cartridge is preferably positioned intermediate of the inlet compartment and the outlet compartment, such that a flow of air moves from the inlet compartment through the filter cartridge, from the first side to the second side, and thereafter into the outlet compartment.

The filter cartridge may be accessed through a filter cartridge cover, for maintenance or replacement purposes. Preferably, the filter cartridge cover being hingedly attached to the housing over an access opening and held closed by way of removable screws. The reader will however appreciate that clips or clasps could also be used to hold the cover closed, or the cover may slidably engage the housing. The opening of the filter cartridge cover may trigger an electromechanical switch or other type of switch, which is configured to disconnect power to the UV light source to thereby inhibit injury to a user from UV radiation discharging through the access opening.

An inlet grille may be attached over the inlet and include fixed vanes and/or a mesh. An outlet fan member, is hingedly connected to the housing over the outlet.

Alternatively, an inlet fan member may be used to force the air through the inlet or inlets, filter and out through the outlet, rather than drawing the air therethrough.

The use and configuration of the fan may be to provide an even speed and generally constant flow of air through the apparatus thereby maximising utilisation of the catalyst, which means greater efficiency is achieved, so that the PCO reaction time and the generation of hydroxyl radicals is enhanced

The housing may be generally divided into three compartments, an electronics compartment for retaining the wiring of the power components, the inlet compartment, and the outlet or PCO process compartment.

The UV light source may be a bank of UV LED light members or another type of ultraviolet radiation source.

Preferably the UV source is a high intensity UV LED technology with a specific UV wavelength, that optimises the photochemical reaction. The UV light emitted may have a wavelength between 200nm and 400nm and more preferably between 200nm to 280nm.

The housing may comprise a number of connected panels and components.

The filter cartridge may be configured to slidably engage a baffle frame member held within the housing. The filter cartridge is preferably configured to pass through the access opening when the filter cartridge cover is open.

The outlet fan member may include an outlet fan, gasket and outlet grille. The UV light source may be accessible through a lamp access port, or may be accessible through the openings formed when the filter cartridge cover or outlet fan member are open.

The power components may include a power inlet, fuse, transformer and power switch. Alternatively, the transformer may be incorporated into a power plug. The apparatus may alternatively include a battery, where mains power is not available.

The power components and circuitry may be configured to control the fan and, in some circumstances, other components, such as but not limited to sensors or transmitters.

The filter cartridge may comprise a plurality of corrugated fibrous cellulose sheets forming an array of hollow tubes or open cells therebetween, or an open honeycomb structure, or a fibrous sheet material or any other type of matrix delineating multiple pores or passageways that permit the air to flow therethrough, thereby maximising surface area contact. A number of pathways or pores preferably extend between the first side and second side of the filter cartridge, wherein the UV light source irradiates the second side and inwardly thereof along the number of pathways or pores through the filter cartridge.

The apparatus may include prefilter/s and/or activated carbon outlet filter/s.

The apparatus may further include sensors to measure air flow, filter efficiency, appropriate fan speed and other quantitative factors, to thereby provide optimal operation of the apparatus. The sensors may also be used to identify carcinogenic compounds in the outgoing airflow or component malfunction/lifespan. The electronics and wiring, or parts thereof, may be contained in any of the aforementioned compartments.

Sensors may be positioned at predetermined locations within the apparatus. The sensors monitor the efficiency of the components of the apparatus both locally and centrally and measure the output of each element thereby allowing for continuous monitoring and control.

The sensors may be gas sensors, selected from a group including non-optical gas sensors, such as but not limited to, wet electrolyte (electrochemical), metal oxide semiconductor, and FIDs, and optical gas sensors, such as but not limited to, NDIR, FTIR, UV DOAS, chemiluminescence and photoionization (VOCs) sensors.

The sensor or sensors may alternatively comprise optical sensors for measuring the reflection of the UV light off the catalyst layer to estimate the degree of contamination/fouling which would influence the effectiveness of the device.

The sensor or sensor may also comprise flow meters for determine the impedance to the flow of air to thereby estimate the amount of particulates and pollutants captured by the filter cartridge. Furthermore, the sensor or sensors may be configured to measure ethylene concentration in the flow of air.

The reader should however appreciate that other types of sensors could be used without departing from the scope of the invention.

The apparatus may also include network capabilities, wherein the operation of the device can be monitored remotely. Some of the components of the system may be connected by way of a communication device such as, but not limited to, a modem communication path, a computer network such as a local area network (LAN), Internet, or fixed cables. The system may also utilise 3G/4G/5G/XG telecommunications networks or similar, or be connectable to a device that utilises such a network. Communication may also be by way of long-range or short-range networks, such as but not limited to low power radio network, microwave data links, BLUETOOTH®, BLUETOOTH® Low Energy (BLE), Wi-Fi, LoRa™, NB-loT or any other type of network.

The apparatus may further include a memory component, wherein the data is temporarily stored therein, before it is transmitted at predetermined intervals or is interrogated by a device to retrieve the data. The memory component may be a nonvolatile storage device.

A processor and the memory component may cooperate with each other and with other components of a computer to perform the functionality described herein. Some of the functionality described herein can be accomplished with dedicated electronics hardwired to perform the described functions.

In one form, the filter cartridge may be constructed from a bio-waste material being biodegradable or compostable, such that after use the catalyst matrix substrate can be removed from within the apparatus and placed in a common green waste stream or used as compost. This means that the cartridge can be removed from the general waste stream which would otherwise end up in landfill.

Preferably, the apparatus includes a replaceable cartridge including the substrate, which allows for easy slide-in I slide-out replacement, such as when indicated by a relevant sensor system, or via a regular replacement schedule.

The apparatus may include a prefilter or prefilters adjacent the inlet for removal of large particulate matter, such as dust and other large diameter pollutants.

The prefilter may also be configured to scavenge ammonia from the flow of air being drawn into the apparatus. An inlet sensor may be positioned inwardly of the prefilter to monitor the flow rate.

An activated carbon filter/s may be positioned adjacent the outlet. The activated carbon filter/s may be configured to remove ozone (O3), which may be a byproduct of the photocatalytic oxidation process.

In one form the photocatalytic material comprises titanium dioxide, and other semi conductive components such as SnO? or Fe2Os coated on an organic matrix of the filter cartridge. One side of the filter cartridge may be impregnated with an oxidation catalyst of precious metal such as Pd, Au, Pr or Ag, or a transition metal oxide of Mo, Nb, V, Ce or Cr.

In another aspect of the invention there is proposed a method of purifying or treating a flow of air, including the steps of: providing an apparatus as hereinbefore described; operating the apparatus to undertake a photocatalytic oxidation process; and using a control system configured to modify the flow rate of the flow of air to thereby control the time period that a volume of air is in contact with the catalyst.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an implementation of the invention and, together with the description and claims, serve to explain the advantages and principles of the invention. In the drawings, Figure 1 is a perspective view of the air purification or treatment apparatus of the present invention;

Figure 2 is a perspective view of the air purification or treatment apparatus of Figure 1 , illustrating the removable screws for holding the filter cartridge cover closed;

Figure 3 is a cross-sectional view through A-A of the air purification or treatment apparatus of Figure 2;

Figure 4 is the cross-sectional view of Figure 3 illustrating the movement of air through the apparatus;

Figure 5 is an exploded view of the air purification or treatment apparatus of Figure 1 ;

Figure 6 is a perspective view of the air purification or treatment apparatus of Figure 1 , illustrating the removal of the screws and opening of the filter cartridge cover;

Figure 7 is the perspective view of Figure 6 illustrating the partial removal of the filter cartridge;

Figure 8 is the perspective view of Figure 7 illustrating the complete removal of the filter cartridge from within the baffle frame member;

Figure 9 is a perspective view of the air purification or treatment apparatus of Figure 1 , illustrating the hinging of the filter cartridge cover and the outlet fan member;

Figure 10 is an end view of the air purification or treatment apparatus of Figure 1 illustrating the power inlet, fuse and power switch;

Figure 11 is an opposite end view of the air purification or treatment apparatus of Figure 1 illustrating the outlet fan member;

Figure 12 is a front view air purification or treatment apparatus of Figure 1 illustrating the inlet grille attached over the inlet;

Figure 13 is a top view of the air purification or treatment apparatus of Figure 1 illustrating the filter cartridge cover;

Figure 14 is an underside view of the air purification or treatment apparatus of Figure 1 ; Figure 15 is a perspective view of one embodiment of the filter cartridge; and

Figure 16 is a partial cross-sectional view through B-B of the filter cartridge of

Figure 15, positioned adjacent a bank of UV LED lights.

DETAILED DESCRIPTION OF THE ILLUSTRATED AND EXEMPLIFIED EMBODIMENTS

Similar reference characters indicate corresponding parts throughout the drawings. Dimensions of certain parts shown in the drawings may have been modified and/or exaggerated for the purposes of clarity or illustration.

Referring to the drawings for a more detailed description, there is illustrated an air purification or treatment apparatus 10, demonstrating by way of examples, arrangements in which the principles of the present invention may be employed.

In one embodiment, as illustrated in the Figures 1 to 14, the air purification or treatment apparatus 10, includes a housing 12, having a UV light source 14 and filter cartridge 16 retained therein. The filter cartridge 16 can be accessed through a filter cartridge cover 18, for maintenance or replacement purposes. The filter cartridge cover 18 is attached to the housing 12 by way of hinges 20 and is held closed by removable screws 22, as illustrated in Figures 1 and 2.

An inlet grille 24 is attached to the housing 12 over an air inlet 26. An outlet fan member 28, is hingedly connected to the housing 12 by way of hinge 30 and held closed by screws 32. The outlet fan member 28 is attached over an air outlet 34, when is a closed configuration.

As illustrated in Figure 3 the housing 12 is generally divided into three compartments: an electronics compartment 36 for retaining the wiring of the power components 38; an inlet compartment 40 positioned between the air inlet 26 and a first side 42 of the filter cartridge 16; and an outlet compartment or PCO process compartment 44 positioned between a second side 46 of the filter cartridge 16 and the air outlet 34. The UV light source 14, comprising a bank of UV LED lights, is positioned within the outlet compartment 44 and is configured to irradiate the second side 46 of the filter cartridge 16. As is further illustrated in Figure 3, in a one embodiment the filter cartridge 16 is coated in the catalyst substance 48 adjacent the second side 46 thereof and can be irradiated by the UV light source 14.

Figure 4 illustrates the movement of the air through the inlet 26 into the inlet compartment 40. The flow of air, indicated by the arrows, then moves in through the first side 42 of the filter cartridge 16 and passes out through the second side 46, which is coated in the catalyst substance 48, into the outlet compartment 44. The flow of air then moves out through the outlet 34 and exits the apparatus 10.

The catalytic reaction produces hydroxyl radicals that non-selectively oxidise organic compounds within the flow of air adjacent the second side 46 of the filter cartridge 16.

The outlet compartment 44 may be referred to as a photocatalytic oxidation chamber (PCO chamber), which is where the PCO process or a substantial portion thereof occurs, wherein the volatile organic compounds (VOCs), bacteria, mould and/or fungal spores are treated by the photocatalytic oxidation (PCO).

As illustrated in Figure 5, the housing 12 includes a number of panels and components. For the sake of clarity, the fasteners and some components will not be described in detail. Some of the fixing means, in the form of bolts or screws have not been illustrated so as to not obscure details of the invention, however the reader will appreciate that such fixing means are configured to engage one or more of the respective holes shown in the figures. Furthermore, the reader will appreciate that the invention is not limited to the illustrated housing and other configurations are possible.

Generally, as shown in Figure 5, the housing 12 includes side wall panels 50, 52, base panel 54, upper panel 56, internal frame members 58, 60, 62, 64, and baffle frame member 66.

The inlet grille 24 is attachable to the side wall panel 50, and the filter cartridge cover 18 is attached to the upper panel 56 by way of hinges 20 and spacers 68. The filter cartridge 16 is configured to slidably engage the baffle frame member 66 and can pass through opening 70 in the upper panel 56, as will be described in relation to Figures 6 to 8. As further illustrated in Figure 5, the outlet fan member 28 engages respective cooperating recesses 72 is the base panel 54 and upper panel 56 and are attached thereto by respective fixing means. The outlet fan member 28 includes an outlet fan 74, gasket 76 and outlet grille 78.

Figures 6 to 8 illustrate the removal of the filter cartridge 16 from within the apparatus 10. To remove the filter cartridge 16 the three screws 22 are removed such that the filter cartridge cover 18 can be pivoted about hinges 20. A user can then grasp the filter cartridge 16 at either end by utilising the finger slots 80 and slidably remove the filter cartridge 16 from within the baffle frame member 66. In this way the filter cartridge 16 can be easily removed and replaced.

As illustrated in Figure 9, both the filter cartridge cover 18 and outlet grille 78, are hingedly connected to the housing 12 to permit access to the internal space of the apparatus 10. The UV light source 14 may also be accessed through a lamp access port (not shown) or may be accessible through the opening formed when the filter cartridge cover 18 or outlet fan member 28 are open.

Figure 10 illustrates an end view of the apparatus 10 illustrating the power components 38, comprising the power inlet 82, fuse 84 and power switch 86. Figure 11 illustrates the opposite end of the apparatus 10 illustrating the position of the outlet fan member 28.

Figures 12 to 14 illustrate the front, top and underside views of the apparatus 10 showing the respective positions of the filter cartridge cover 18, power components 38, inlet grille 24 and outlet grille 78.

Figures 15 and 16, illustrate one possible configuration of the filter cartridge 16, comprising a plurality of corrugated fibrous cellulose sheets forming an array of hollow tubes or open cells therebetween. The filter cartridge 16 produces turbulent flow of air rather than laminar flow. The reader should appreciate that the figures are provided for illustration purposes only and any type of open cell, open honeycomb structure or fibrous sheet could be used without departing from the scope of the invention. Furthermore, although the arrows indicating the movement of air through the filter are straight, this should not be interpreted as laminar air flow, since the configuration of the filter of the preferred embodiments would result in turbulent air flow through the filter. Generally, the filter cartridge 16 could be understood to be a matrix delineating multiple pores or passageways that permit the air to flow therethrough, thereby maximising surface area contact. As the air passes through the matrix the volatile organic compounds (VOCs), bacteria, viruses, mould, fungal spores and/or other pathogens are treated by the photocatalytic oxidation (PCO) process adjacent the second side of the filter cartridge 16.

As illustrated, the filter cartridge 16 includes a first side 42 which is positioned adjacent the inlet compartment 40 and a second side 46 positioned adjacent the outlet compartment 44. The catalyst substance coating 48 is applied to the filter cartridge 16 adjacent the second side 46 which is irradiated 88 by the UV light source 14.

This means that as the air is drawn in through the inlet compartment 40 (shown in Figure 1 ) the larger particulates 90 are captured by the filter cartridge 16 adjacent the first side 42, as illustrated in Figure 16. As the reader should now appreciate, since the larger particulates are captured by the filter cartridge 16 adjacent the first side of the filter, they are thereby inhibited from fouling the catalyst substance coating 48, which would reduce the efficiency of the apparatus 10. In this way the lifespan of the catalyst substance coating 48 is enhanced and therefore the time between required filter cartridge replacement is increased.

The configuration of the filter cartridge 16 may reduce the need for prefilters, however the reader will appreciate that in some circumstances prefilters may be used. An activated carbon outlet filter (not shown) may also be positioned adjacent the air outlet 34. The activated carbon outlet filter may be configured to act like a sponge wherein any odour-causing vapours are captured. All filters may be replaceable.

Various sensors (not shown) may be used to measure air flow, filter efficiency, appropriate fan speed and other quantitative factors, to thereby provide the optimum time for photocatalytic oxidation within the PCO process chamber 44. The use of sensors and controllers may assist in the optimal operation of the apparatus 10 and can be used to identify carcinogenic compounds in the outgoing air flow or component malfunction/lifespan. The power components 38 and circuitry may be configured to control the outlet fan 74 and, in some circumstances, other components, such as but not limited to sensors or transmitters.

In use the power components 38 of the present embodiment are configured to operate the outlet fan 74 to thereby draw air in through the air inlet 26. The larger particulate matter 90 is filtered by the fibrous cellulose material adjacent the first side 42 of the filter cartridge 16, this includes dust and other large diameter pollutants which could otherwise foul or contaminate the catalyst substance coating 48, which would influence its efficiency.

The skilled addressee will now appreciate the advantages of the illustrated invention over the prior art. In one form, the apparatus is configured to purify or treat a flow of air passing therethrough by way of photocatalytic oxidation, wherein a single replaceable, biodegradable filter cartridge is used. In some embodiments, the speed with which the air is passed through the apparatus may also be monitored and controlled to optimise the photocatalytic oxidation process and minimise the generation of carcinogenic compounds.

Various features of the invention have been particularly shown and described in connection with the exemplified embodiments of the invention, however it must be understood that these particular arrangements merely illustrate the invention and it is not limited thereto. Accordingly, the invention can include various modifications, which fall within the spirit and scope of the invention. In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.