GB2505432A

GB2505432A - Air purifier which directs the air flow over a surface of water

Info

Publication number: GB2505432A
Application number: GB1215351.6A
Authority: GB
Inventors: Dave Osh
Original assignee: QUEST ION Pte Ltd
Current assignee: QUEST ION Pte Ltd
Priority date: 2012-08-29
Filing date: 2012-08-29
Publication date: 2014-03-05
Also published as: GB201215351D0

Abstract

Air purifier apparatus comprises a housing (10) providing an enclosure above a base (18). The housing (10) has an air inlet (22) and an air outlet (24) from the enclosure, the housing being divided internally by at least one cross wall (11) to define an air inlet chamber (13) and an air outlet chamber (15). A reservoir (20) filled with water (36) is mounted below the base (18) such that an air channel (50) remains between the surface of the water and the base (18). A first opening (28) and a second opening (29) in the base (18) allows the channel (50) to communicate with the chambers (13, 15). An air impeller (14) is mounted in the outlet chamber (15) and is operative to draw air from the inlet chamber (13), through the channel (50) from the first opening (28) to the second opening (29) and finally through an air filter (30) mounted in a compartment (39) between the outlet chamber and the air outlet. The air filter preferably includes a membrane of polyethylene terephthalate (PET) having a pore size low enough to trap particles of a size equal to or greater than 0.1 Î¼m.

Description

AIR PURIFIER

[0001] This invention relates to apparatus for purifying air by removal of particles, such as inorganic dust or particles of organic origin, such as bacteria, fungal spores, pollen, dust mites and the like, and removal of gases, including carbon dioxide, sulphur dioxide, cigarette smoke and odorous substances.

BACKGROUND

[0002] Air filtration apparatus is known where air to be purified is fed through a body of water, which traps particles and dissolves gases. An alternative method whereby air to be purified is merely directed at and across the surface of a body of water is disclosed in WOO1/26781. In this proposal, an air impeller directs jets of air through a nozzle onto the surface of water in a direction substantially perpendicular to the water surface. The air spreads across the surface and it is stated that the heavier particles carried in the air penetrate the liquid surface and remain there, that bacteria are destroyed and that gases in the air are removed into the water. At the same time, some water evaporates into the air, thereby humidifying the air which exits the apparatus.

[0003] An object of the present invention is to provide equally effective or improved air purification apparatus, which can be operated continuously with low energy consumption, and minimal noise.

BRIEF SUMMARY OF THE DISCLOSURE

[0004] According to the present invention air purifier apparatus comprises a housing providing an enclosure above a base, the housing having an air inlet to the enclosure and an air outlet from the enclosure, the housing being divided internally by at least one cross wall to define an air inlet chamber in communication with the air inlet and an air outlet chamber in communication with the air outlet; a reservoir of water mounted below the base such that an air channel remains between the surface of the water and the base; a first opening in the base whereby the inlet chamber is in communication with said channel and a second opening in the base whereby the outlet chamber is in communication with said channel; an air impeller mounted in the outlet chamber and operative to draw air from the exterior via the inlet chamber, through the channel from the first to the second opening, and thereby across the surface of the water, to be returned to the exterior from the outlet chamber; and an air filter mounted between the outlet chamber and the air outlet for passage of all air there through before it exits the apparatus.

[0005] Preferably the air filter has a pore size low enough to trap or exclude particles equal to or greater than 0.1 pm in size.

[0006] Preferably the air filter is made of polyethylene terephthalate (PET). Preferably, the air filter isa" nano-membrane". A nano-membrane is defined as a free-standing structure having a thickness in the range of 1-100 nm and an aspect ratio of over 1 million. Nano-membranes are commonly fabricated using a layer by layer assembly method. A preferred filter material of the invention is fabricated using such method, but may be in the range between 50 and 200 nm in thickness.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The invention will be described further, by way of example, with reference to the accompanying drawings, in which: tO Figure 1 is a perspective view of the exterior of a preferred embodiment of the air purifier apparatus of the invention; Figure 2 is an enlarged scale perspective view of the remote control for the apparatus of figure 1; Figure 3 is a perspective view showing the same apparatus with the upper housing separated from the lower liquid reservoir, the latter in the process of being replenished; Figure 4 is a fragmentary perspective view of the underside of the housing showing removal of the filter element; Figure 5 is a perspective view of the filter element; Figure 6 shows how the filter element is opened to remove and replace the filter membrane; and Figure 7 is a diagrammatic longitudinal cross-section through the apparatus of figure 1.

DETAILED DESCRIPTION

[0008] Referring to the drawings, a preferred practical embodiment of the air purification apparatus of the invention comprises an upper housing 10 which, in use, is mounted onto a lower liquid reservoir in the form of a water tank 20, a removable filter element 30 (figures 4, Sand 6) fitted into one end of the housing 10, a remote control unit 40, and conventional power supply means (not shown).

[0009] The housing 10 is of inverted U-shape in cross-section and aesthetically designed with curving contour. Centrally, at one side it is provided with an elongated recess to provide a carrying handle (not shown). At the other side of the exterior there is a manual power switch button 12 whereby the apparatus, specifically an internal air impeller in the form of a fan 14, can be switched on and off and with low-speed or high-speed operation.

Surrounding the button 12, is an indicator light 16 which is illuminated when the power is switched on. Also adjacent or surrounding the button 12 is an infrared receiver whereby signals from the remote control unit 40 can be used to actuate the apparatus, instead of manual actuation. The base of the housing 10 is defined by a base wall 18. At each end the housing 10 has a respective end wall 19 shaped as a hyperbola and provided with a series of generally vertical slots which serve, respectively, as air inlets 22 and air outlets.

Projecting vertically arranged ribs 26 are formed on each end wall 19 and extend between the air inlets/outlets 22, 24. The base wall 18 has a series of first openings 28, which are elongated parallel to the longer axis of the housing 10, arranged side-by-side transversely of the length of the housing 10 at the end adjacent the air inlets 22, which will be termed the inlet end of the housing. The base wall 18 also has two rows of second openings 29, also elongated parallel to the longer axis of the housing 10, in the vicinity of the housing end adjacent the air outlets 24, which will be termed the outlet end of the housing. This is clearly shown in figure 3.

[0010] Internally, the housing 10 is divided by a transverse cross wall 11 into an inlet chamber 13 at the inlet end and an outlet chamber 15 at the outlet end, the outlet chamber being somewhat larger than the inlet chamber 13, as shown in figure 7. Inside the outlet chamber 15, the fan 14 is mounted onto a supporting wall 17 which extends ata spacing above the base wall 18. Finally, adjacent the outlet end, a short spacing inside the end wall 19 provided with the outlets 24, there is a narrow, substantially vertical compartment 39 to receive and accommodate the filter element 30.

[0011] The water tank (lower reservoir) 20 is formed as a relatively shallow tray having a base 23 of curving profile in the lengthwise direction of the apparatus and opposing side walls 21 which taper from a maximum height at the central region towards each end. The base 23 is provided with support feet 25. One of the side walls 21 has a transparent insert as a window 27 at a central location to provide visual indication of the level to which the reservoir 20 is filled, in use of the device, as shown in figure 3. Maximum and minimum fill levels are indicated externally on that side wall. Internally, the water tank 20 is provided with two spaced apart cross walls 42, 44 to enhance rigidity of the tray and minimise liquid motion when the tray is filled. The cross walls 42, 44 have openingslrecesses so that the liquid spreads evenly and the liquid surface is level throughout the reservoir when it is filled.

[0012] In a specific practical embodiment the size of the housing when mounted onto the reservoir may be 350 mm in length, 200 mm in width and about 295 mm high and the majority of the components may be made of ABS plastics material. A suitable size of fan 14 is about 90x90x30 mm with potential fan speed up to 4000 rpm. Power supply to the fan 14 is suitably by connection to mains via a transformer to provide 12 volt supply with current approximately 170 Ma. However, these details are provided purely by way of example and may be varied in other embodiments within the scope of the invention.

[0013] The filter element 30, as shown in figures 5 and 6, advantageously comprises a sheet 32 of a commercially available "nano-membrane" material with a pore size of 0.1 pm supported upon and sandwiched between a pair of apertured plastics frames 34. A suitable material of the nano-membrane is a polyethylene terephthalate (PET) based polymer composite. A suitable thickness for this material is less than 0.2 pm (200 nm), preferably about 0.1 pm. Again, these details are only provided by way of example and other types, dimensions, thicknesses of filter material and other manners of mounting of same may be employed in alternative embodiments within the scope of this invention.

[0014] The apparatus as described is for use indoors, typically in a domestic dwelling or office location. The housing 10 can be carried and moved by means of the handle (not shown). It is a relatively loose fit onto the lower reservoir/water tank 20 so it is not recommended to lift the entire apparatus by the handle. At or close to a location where the apparatus is to be brought into use and with the housing 10 lifted away from the water tank 20, as shown in figure 3, the tank 20 is filled with water. Water can be taken directly from the tap or any other clean water source. The tank 20 is filled with clean water to a level between the minimum and maximum markings on the window 27. The housing 10 is then fitted or re-attached above the tank 20. In this embodiment the lower peripheral edge of the housing 10 is conveniently a simple friction press fit over a shallow up stand lip 45 extending adjacent the periphery of the tank 20 with only a modest degree of force required to connect or disconnect these. However, other means of inter-engagement and disconnection of the upper housing 10 and the tank 20 may be employed in other embodiments including any suitable fastener or catch means. After the housing 10 is fitted onto the tank 20, a power cable (not shown) is connected between mains power supply and circuitry in the housing connected to the fan 14, typically with appropriate transformer in between, as previously mentioned, for 12 V direct current power supply to the fan 14.

[0015] When the housing 10 is fitted onto the tank 20, with the latter filled with water to the appropriate level (between minimum and maximum) a gap of between 1 and 3 cm in height remains between the surface of the water and the base wall 18 of the housing, defining a channel 50 through which air will flow from the inlet chamber 13 to the outlet chamber lswhen the fan 14 is operating.

[0016] The fan 14 is actuated either manually by means of the pushbutton switch 12 or by use of the remote control device 40. The indicator light 13 shows whether the fan is operating at low speed (blue light) or high-speed (red light).

[0017] With reference to figure 7, air from the surrounding atmosphere of the room is drawn into the housing 10 through the air inlets 22. Typical airflow may be between 25 and GEM (approximately 11,500 to 12,500 cm3 per second at low and high fan speed respectively) at the inflow. The air passes through the inlet chamber 13, through the first openings 28 in the base wall 18, and along the aforesaid channel 50 and into the outlet chamber 15 by way of the rows of second openings 29. The flow path of the air is upwards to pass through the fan 14 and into the upper region of the outlet chamber 15. The air will typically decelerate in this region. It then passes through the filter element 30, more specifically the nano-membrane 32, before exiting through the outlets 24 back into the surrounding atmosphere. Typical outflows speed may be between 20 and 25 CFM (approximately 10,500 to 11,500 cm3 per second at low and high fan speed respectively).

[0018] Air flowing from the inlet chamber 13 into the channel 50 is forced towards the surface of water in the tank 20, mostly at an angle of less than 90°. Therefore most particulate material is trapped by the water. Heavier, mainly inorganic particles puncture the surface of the water and fall to the bottom of the tank 20. Lighter particles, primarily organic in nature, including dust mites, bacteria, spores, pollen, epithelia dust and animal hairs are likely to be trapped on the surface, and will either be wetted and then sink, or remain floating, trapped by the surface tension. Gaseous substances in the air will also tend to be absorbed or dissolved in the water owing to the force and direction of airflow. All of these effects are enhanced by the length and narrowness of the channel 50 above the surface of the water through which the air is constrained to flow by the structure and layout of the housing 10 and the tank 20 to which it is attached. In other words, the air is exposed to the water surface for a relatively long distance, typically between 5 and 30 cm, preferably between 10 and 20 cm. Additionally, the airflow across the surface of the water and the trapping of pollutant particles by the surface tension, or by speed of air at the region below the first openings 28, sets up small waves on the surface of the water in the pool which further enhances the possibilities for trapping lighter pollutant particles and absorption of gaseous pollutants from the air. Therefore, in the context of the apparatus as a whole, the water pool acts as a first stage purification system owing to the air current and the water current both acting to bring about the extraction of particles greater than about pm and gas from the air into the water.

[0019] The level of the water should be monitored by quick and simple visual inspection of the window 27. It will need to be topped up periodically, or replaced completely, along with removal of the accumulated debris (trapped particles).

[0020] Once the air has passed through the fan 14, its subsequent passage through the filter element 30. more specifically the nano-membrane 32, constitutes a second stage of purification. The thin membrane of PET traps particles greater than 0.1 pm in size, thus removing from the air circulating through the apparatus any remaining particles greater than 10 pm which have not been removed in the first water surface purification stage, as well as smaller particles between 0.1 and 10 pm, so that the air exiting from the outlets 24 may be considered 99% pure by that stage, in that 99% of original pollutants can be expected to have been removed by passage through the apparatus.

(0021] The nano-membrane 32 should be replaced after six months to one year depending on the quality of the air being circulated through the air purifier device and the total period of operation. To change the membrane 32, with the power turned off, the housing 10 should be lifted off from the water tank 20 and placed on its side, as shown in figure 3, or inverted. An edge of the filter element 30 protruding from the compartment can then be accessed and withdrawn by means of a recess or opening providing a hand grip, as shown in figure 4. The element 30 is pulled out for inspection of the membrane 32 and if it is a dusty brown in colour it should be replaced, as this colouration indicates that the pores are becoming clogged with particles. One of the plastic frames 34 is unclipped and lifted, as shown in figures 5 and 6 so that the dirty, used membrane 32 can be removed from the other supporting frame 34 and replaced. The frames are then close together again and the element 30 slid back into the compartment 39 and the housing 10 is filled back onto the tank 20 by reverse sequence of operations, ready for further operation of the apparatus as a whole.

(0022] An additional advantage of this apparatus is that the air flowing through the apparatus, in addition to being purified, is raised to a comfortable level of humidity by the passage across the water surface and consequent evaporation of water into the air which returns to the surrounding atmosphere. Indeed, the air may circulate many times through the apparatus during the course of operation of the apparatus, i.e. it may be continuously circulating for a considerable period of time.

(0023] The foregoing is illustrative and not limitative of the scope of the invention. In other words, the invention is not restricted to the details of any foregoing embodiment. Many other variations in detail are possible in other embodiments.

(0024] Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of them mean "including but not limited to", and they are not intended to (and do not) exclude other components. Features described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith.

Claims

CLAIMS1. Air purifier apparatus comprising: a housing providing an enclosure above a base, the housing having an air inlet to the enclosure and an air outlet from the enclosure, the housing being divided internally by at least one cross wall to define an air inlet chamber in communication with the air inlet and an air outlet chamber in communication with the air outlet; a reservoir of water mounted below the base such that an air channel remains between the surface of the water and the base; and an air impeller mounted in the enclosure and operative to draw air from the exterior via the inlet chamber, into contact with the surface of the water, to be returned to the exterior from the outlet chamber; characterised in that the air impeller is mounted in the outlet chamber; in that a first opening is provided in the base whereby the inlet chamber is in communication with said channel and a second opening is provided in the base whereby the outlet chamber is in communication with said channel; in that the air impeller is operative to draw air from the exterior via the inlet chamber, through the channel from the first to the second opening, and thereby across the surface of the water, to be returned to the exterior from the outlet chamber; and in that an air filter is mounted between the outlet chamber and the air outlet for passage of all air there through before it exits the apparatus.
2. Air purifier apparatus according to claim 1 wherein the air filter has a pore size low enough to trap particles of a size equal to or greater than 0.1 pm.
3. Air purifier apparatus according to claim 1 or claim 2 wherein the air filter comprises polyethylene terephthalate (PET).
4. Air purifier apparatus according to any preceding claim wherein the air channel has a length between the first opening and the second opening of between 50 and 250 mm, preferably between 100 and 200 mm.
5. Air purifier apparatus according to any preceding claim wherein the air channel has a height between 10 and 30mm, preferably between 15 and 20 mm.
6. Air purifier apparatus according to any preceding claim wherein the air impeller is mounted in the outlet chamber in a central region of the housing.
7. Air purifier apparatus substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings. l0