WO2016007086A1

WO2016007086A1 - A filter device

Info

Publication number: WO2016007086A1
Application number: PCT/SG2015/000133
Authority: WO
Inventors: Jeffery Philip OBBARD; Chen-Kun Wang
Original assignee: Airazor Technologies Pte Ltd
Priority date: 2014-07-08
Filing date: 2015-07-08
Publication date: 2016-01-14
Also published as: SG10201505357YA

Abstract

A filter member for use with a fan or room ventilator of the type including at least one rotatable fan member, the filter member comprising at least one first filter layer arranged to filter airborne particulate matter whilst permitting air to pass through the at least one first filter layer, and at least one second filter layer arranged to capture volatile organic compounds and thereby substantially remove volatile organic compounds from air that passes through the filter member, the at least one second filter layer having substantially no effect on the rate of air flow through the filter member.

Description

A FILTER DEVICE

Field of the Invention The present invention relates to a filter device for improving the quality of ambient air inside a room, to a filter member for use with such a filter device, and to a fan or room ventilator provided with a filter member.

Background of the Invention

It is known that suspended airborne particulate matter that measures 2.5 microns in diameter or less (referred to as PM<2.5) constitutes a health risk to people, both from a short term (acute) and long term (chronic) health perspective. Air purifiers seek to lower the concentration of PM<2.5 in an indoor environment, and typically such devices rely on positive pressure filtration to force air across a filter configured to remove PM<2.5 to a high degree of efficiency (of the order of 99.5% or higher).

However, while such air purifiers operate at a high level of filter efficiency, their effectiveness at lowering the overall concentration of PM<2.5 in a room may be relatively low because the rate of removal of PM<2.5 from ambient air is dependent on more than just the efficiency of PM<2.5 removal by the filter alone. The rate at which air volume is processed through the filter, as well as the influx of PM<2.5 into the indoor environment from the external environment are also important factors in determining the prevailing concentration of PM<2.5 in the indoor environment.

Therefore, filter efficiency must also be balanced with sufficient airflow through the filter to achieve an effective overall reduction in PM<2.5 concentration in ambient air within a room.

Summary of the Invention

In accordance with a first aspect of the present invention, there is provided a filter member for use with a fan or room ventilator of the type including at least one rotatable fan member, the filter member comprising:

at least one first filter layer arranged to substantially filter airborne particulate matter having a diameter of at least about 0.3 microns whilst permitting at least about 1.5m/s of air to pass through the at least one first filter layer; and

at least one second filter layer arranged to capture volatile organic compounds and thereby substantially remove volatile organic compounds from air that passes through the filter member, the at least one second filter layer having substantially no effect on the rate of air flow through the filter member when the airflow through the filter member is about 1 ,5m/s.

In an embodiment, the filter member is configured so as to be receivable in a filter cover arranged to attach externally to an air outlet of a fan or room ventilator.

In an embodiment, the filter member is configured so as to be received in a fan or room ventilator between at least one rotatable fan member and an air outlet.

In an embodiment, the filter member has a width substantially the same as the width of the air outlet of the fan or room ventilator with which the filter member is to be used. In an embodiment, the filter member includes at least one rim portion disposed adjacent a peripheral edge of the filter member. The filter member may include first and second oppositely disposed rim portions.

In an embodiment, the first filter layer includes at least one filter portion arranged to filter airborne particulate matter having a diameter of at least about 0.3 microns and at least one support portion arranged to provide structural support to the at least one filter portion.

In an embodiment, the at least one filter portion includes polypropylene melt-blown fibre material, for example a web of polypropylene melt-blown fibre material folded into pleats.

In an alternative embodiment, the at least one filter portion includes glass or synthetic fibre material.

The at least one support portion may include polyester and rayon material

In an embodiment, the first and second filter portions are disposed in alternate transverse layers in the first filter layer.

In an embodiment, the filter member is substantially flat. In an embodiment, the second filter layer includes activated carbon material, and may include a mesh layer of polyester material impregnated with activated carbon.

In an alternative embodiment, the at least one second filter layer includes non-woven activated carbon, open cell activated carbon foam or honeycomb type activated carbon material.

In an embodiment, the filter member has a substantially circular or rectangular cross sectional shape.

In accordance with a second aspect of the present invention, there is provided a filter device comprising;

a filter member having at least one first filter layer arranged to filter airborne particulate matter having a diameter of at least about 0.3 microns whilst permitting at least about 1.5m/s of air to pass through the first filter layer, and at least one second filter layer arranged to capture volatile organic compounds and thereby substantially remove volatile organic compounds from air that passes through the filter member, the at least one second filter having substantially no effect on the rate of air flow through the filter member;

a filter cover arranged to receive the filter member and arranged to attach externally to an air outlet of a fan or room ventilator of the type including at least one rotatable fan member, the filter cover including:

a permeable portion disposed during use adjacent the filter member when the filter member is received in the filter cover, the permeable portion arranged to permit substantially unrestricted airflow through the permeable portion; and

a substantially impermeable retaining portion arranged to retain the filter cover relative to the fan or room ventilator during use;

wherein the filter member is shaped and the filter cover is arranged such that substantially all air moved by the fan or room ventilator is directed through the filter member when the filter member is received in the filter cover and the filter cover is attached externally to the fan or room ventilator.

In an embodiment, the substantially impermeable retaining portion comprises a band portion and a resilient portion arranged to facilitate attachment of the cover member to the fan, the band portion extending between the permeable portion and the resilient portion. The resilient portion may include a circumferential elastic portion disposed adjacent a free circumferential edge of the substantially impermeable retaining portion.

In accordance with a third aspect of the present invention, there is provided a fan comprising:

a housing portion connected to a protective cage portion so as to define an internal cavity for receiving at least one rotatable fan member; and

at least one filter member according to the first aspect of the present invention, the filter member disposed in the cavity between the at least one rotatable fan member and the protective cage.

In accordance with a fourth aspect of the present invention, there is provided a room ventilator comprising:

a housing having a permeable inlet and a permeable outlet;

at least one rotatable fan member mounted in the housing;

at least one filter member according to the first aspect of the present invention, the room ventilator arranged such that the housing is retainable relative to a window with the permeable inlet facing outwardly of the room and the permeable outlet facing inwardly of the room; and

the room ventilator arranged such that at least one rotatable fan member causes air to flow from the permeable inlet to the permeable outlet and through the at least one filter member.

In an embodiment, the filter member is disposed in the housing between the at least one rotatable fan member and the permeable outjet.

In an embodiment, the filter member is configured so as to be receivable in a filter cover arranged to attach to the room ventilator over the permeable outlet.

In an embodiment, the housing is engageable with and disengageable from a stand so as to thereby provide a free standing room ventilator.

Brief Description of the Drawings

The present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a diagrammatic representation of a filter device in accordance with an embodiment of the present invention for use with a conventional ventilation fan; Figure 2 is a diagrammatic partially cut away view of a filter member of the filter device shown in Figure 1 , the filter member in accordance with an embodiment of the present invention;

Figure 3 is a diagrammatic side view shown in partial cross section of the filter member shown in Figure 2 taken along the line III- III in Figure 2;

Figure 4 is a diagrammatic representation of the filter device shown in Figures 2 and 3 with a filter cover and filter member of the filter device shown separately;

Figure 5 is a diagrammatic exploded representation of a fan in accordance with an embodiment of the present invention;

Figure 6 is a diagrammatic representation of a room ventilator in accordance with an embodiment of the present invention;

Figure 7 is a diagrammatic representation of a ventilator housing and stand of the room ventilator shown in Figure 6, with the ventilator housing shown separated from the stand;

Figures 8 and 9 are diagrammatic representations of the ventilator housing of the room ventilator shown in Figure 6, with a cover member of the ventilator housing shown partially removed; and

Figure 10 is a diagrammatic exploded representation of the ventilator housing shown in Figure 6.

Description of an Embodiment of the Invention

Referring to the drawings, a filter device 10 for use with a ventilation fan 12 is shown. The fan 12 is of conventional type that includes at least one rotatable fan member, in this example a rotor blade, disposed inside a protective cage. In this example the fan 12 has a cage of approximately 45cm diameter and a rotor blade of approximately 40cm diameter.

The filter device 10 is configured so as to be engageable with the fan 12 such that during use air moved by the fan is urged to move through the filter device 10, as described in more detail below.

As shown more particularly in Figures 2 and 3, a filter member 14 of the filter device 10 is shown. The filter member 14 is of generally flat circular configuration and includes several filter layers, in this example a first filter layer 16 and a second filter layer 18 sandwiched between first and second rim portions 20, 22. The first filter layer 16 is arranged to filter airborne particles measuring at least about 0.3 microns in size from ambient air, whilst allowing a sufficiently high airflow to yield an effective reduction in PM<2.5 concentration in a room. In order to facilitate sufficiently high air flow through the filter member 14 to effect a reduction in PM<2.5 5 concentration, a filter configuration is used that is capable of passing about 1.5m/s of air through the first filter layer 16 when the filter device 10 is engaged with the fan 12.

In this example, the first filter layer 16 has alternating transversely disposed sub-layers including a first sub-layer 17 formed of a web of polypropylene (PP) melt-blown fibre i o material folded in a pleated configuration, and a second sub-layer 19 formed of

polyester and rayon fibres that provides the first filter layer 16 with the necessary structural integrity and strength.

In this example, the diameter of the filter member 14 is approximately 45cm; the first 15 filter layer 16 is arranged to provide approximately a MERV 13 filtration efficiency; the first filter layer 16 is configured to permit air flow of about 0.0661 m³/s; and the typical pressure drop across the first filter layer 16 is about 17.65Pa.

Also in this example, the first sub-layer 17 has a width of about 2.5cm and the second 20 sub-layer 19 has a width of about 3mm.

However, while the present embodiment uses a polypropylene (PP) melt-blown fibre first sub-layer 17, it will be understood that alternatives are possible. For example, the first sub-layer 17 may be formed of glass fibre media or synthetic fibre media that can 25 achieve similar filtration efficiency.

The second filter layer 18 is arranged to remove volatile organic compounds, such as formaldehyde, that are typically associated with undesirable odours, for example associated with smoke-haze.

30

In this example, the second filter layer 18 includes a mesh layer of activated carbon material formed of polyester (PET) fibres impregnated with activated carbon. The mesh size of the second filter layer 18 is chosen so as to be sufficiently large that the second filter layer 18 has a negligible effect on the rate of airflow through the filter member 14 35 when the filter device 10 is engaged with the fan 12. In this example, the mesh size is about 4mm diameter. However, it will be understood that other types of structures and materials are envisaged for the second filter layer 18, the important aspect being that the second filter layer 18 is capable of removing volatile organic compounds from air that passes through the second filter layer 18 without unduly affecting the rate of airflow through the filter member 14 when the filter device 10 is engaged with the fan 12. For example, the second filter layer 18 may be include nonwoven activated carbon, open cell activated carbon foam or honeycomb type activated carbon filter media.

Each of the rim portions 20, 22 in this example is of generally annular configuration and comprises a polypropylene (PP) structure that is biodegradable because polypropylene is liable to chain degradation on exposure to heat and UV radiation. The rim portions 20, 22 enable a user to handle the filter member 14 without touching the first or second filter layers 16, 18. In this example, the rim portions 20, 22 are approximately 29mm wide and 2mm thick.

In this example, the filter member 14 has a thickness of approximately 2.54cm, with the first filter layer 16 about 24mm thick and the second filter layer 18 about 1 mm thick, although it will be understood that any suitable thicknesses for the first and second filter layers 16, 18 are envisaged.

The filter member 14 is receivable in a filter cover 24 shown more particularly in Figure 4, the filter cover 24 including a mesh layer 28 configured to permit substantially unrestricted airflow through the mesh layer 28 when the filter device 10 is engaged with the fan 12, and a retaining band 29 extending from the mesh layer 28 and having a circumferential elastic portion 30 at an edge of the retaining band 29.

During use, the filter member is received in the filter cover 24 such that the first filter layer 16 is disposed adjacent the mesh layer 28 and the second filter later 18 is disposed adjacent the fan cage 26 when the filter device 10 is attached to the fan 12.

The retaining band 29 and the elastic portion 30 are arranged to enable the filter cover 24 to be engaged with the fan cage 26. In this example, the retaining band 29 is configured so as to cover about 1/3 of a rear portion of the fan cage 26, thereby leaving a sufficient rear portion of the fan cage 26 open to allow adequate intake of air.

The retaining band 29 is formed of substantially impermeable material, in this example polyester material, although it will be understood that any suitable substantially impermeable material is envisaged.

The filter member 14 and the filter cover 24 both have a generally circular

configuration. It will be understood that the shape and size of the filter cover 24 and the filter member 14, and the configuration of the retaining band 29 and the elastic portion 30 are such that, when the filter device 10 is engaged with the fan 12, the filter member 14 is tightly disposed against the fan cage 26 such that substantially all air moved by the rotor blade of the fan 12 passes through the filter member 14 and the mesh layer 28 with substantially no opportunity for leakage of air around sides of the filter member 14.

It will be appreciated that the first and second layers 16, 18 of the filter member 14 are configured such that the filter member is able to filter particles measuring at least about 0.3 microns in size from ambient air at a sufficiently high rate to achieve an effective reduction in PM<2.5 concentration in a room, and at the same time substantially remove VOCs from the room. In other words, when the filter device is used with a fan in a room, the filter member 14 reduces the amount of VOCs, and provides a practical balance between PM<2.5 particle removal efficiency and effectiveness in reducing particle concentration in the room because a sufficiently high airflow through the filter member 14 can be achieved.

In an alternative embodiment shown in Figure 5, instead of receiving the filter member 14 in a filter cover 24 and attaching the filter cover 24 externally to a conventional fan 12, a fan 40 according to an embodiment of the invention may be provided that includes an internally disposed filter member 14.

In this embodiment, the fan 40 includes a housing portion 42 connected to a protective cage portion 44 so as to define an internal cavity for housing at least one rotatable fan member 46. The housing portion 42 and the cage portion 44 are shaped such that the filter member 14 is receivable in the internal cavity with the filter member disposed between the rotatable fan member 46 and the protective cage 44.

The protective cage 44 is readily disconnectable from the housing portion 42 in order to facilitate replacement of the filter member 14, for example by connecting the protective cage 44 to the housing portion using corresponding projections and grooves that engage with each other when the protective cage 44 is rotated relative to the housing portion 42, or using screws. In a further alternative embodiment shown in Figures 6 to 10, a room ventilator 50 incorporates a filter member 52 of similar characteristics to the filter member 14 shown in Figures 1 to 5. As with the filter member 14 shown in Figures 1 to 5, the filter member 52 is arranged to filter airborne particles measuring at least about 0.3 microns in size from ambient air, and substantially remove volatile organic compounds from ambient air, whilst allowing a sufficiently high airflow of the order of .5m/s to yield an effective reduction in PM<2.5 concentration in a room. The room ventilator 50 in this example is arranged so as to operate free standing or connect to a window, for example by connecting to a louvre/slat mechanism provided on the window. For this purpose, the room ventilator 50 includes a ventilator housing 53 and a stand 54, with the ventilator housing 53 selectively engageable with and disengageable from the stand 54.

The ventilator housing 53 has a base portion 56 and a cover member 58 engageable with and disengageable from the base portion 56, in this example by providing grooves 60 in the base portion 56 and complimentary projections 62 on the cover member 58. The base portion 56 houses at least one rotatable fan member 64, in this example 4 fan members 64, and the filter member 52 is receivable in the ventilator housing 53 between the fan members 64 and the cover member 58 when the cover member 58 is engaged with the base portion 56. The base portion 56 has apertures 66 that serve as a permeable inlet, and the cover member 58 has a permeable mesh 65 that serves as a permeable outlet.

The ventilator housing 53 can be used as a free standing room ventilator by engaging the ventilator housing 53 with the stand 54.

In this example, in order to facilitate engagement and disengagement of the ventilator housing 53 with the stand 54, the stand 54 is provided with grooves 68 that are arranged to receive sides 70 of the base portion 56. The ventilator housing 53 is configured so as to be retained relative to a window (not shown) of louvre/slat type, with the permeable inlet facing outwardly of the room and the permeable outlet facing inwardly of the room. In this example, this is achieved by removing a louvre/slat from a louvre/slat retaining device on a window and disposing ends 72, 74 of the base portion 56 in the louvre/slat retaining device in place of the removed louvre/slat. In an alternative arrangement, instead of disposing the filter member 52 in the ventilator housing 53 between the rotatable fan member(s) 64 and the permeable cover member 58, the filter member may be attached externally of the ventilator, housing 53, for example by receiving a filter member similar to the filter member 14 in a filter cover arranged to attach externally to the ventilator housing 53 over the cover member 58.

It will be understood that by enabling the room ventilator 53 to attach to a window, an arrangement is provided wherein PM<2.5 filtered air is delivered into a room from outside the room, thereby reducing the concentration of PM<2.5 in the room by increasing the air pressure in the room and reducing ingress of external air into the room.

It will be understood that while the above embodiments include a generally flat circular filter member, other shapes are possible, for example depending on the shape of the fan with which the filter device is to be engaged. For example, the filter member may be rectangular shaped or otherwise shaped such that the shape of the filter member is complementary to the shape of the fan or room ventilator.

Modifications and variations as would be apparent to a skilled addressee are deemed to be within the scope of the present invention.

Claims

Claims:

1. A filter member for use with a fan or room ventilator of the type including at least one rotatable fan member, the filter member comprising:

at least one first filter layer arranged to filter airborne particulate matter having a diameter of at least about 0.3 microns whilst permitting at least about 1.5m/s of air to pass through the at least one first filter layer; and

at least one second filter layer arranged to capture volatile organic compounds and thereby substantially remove volatile organic compounds from air that passes through the filter member, the at least one second filter layer having substantially no effect on the rate of air flow through the filter member when the airflow through the filter member is about 1.5m/s.

2. A filter member as claimed in claim 1 , wherein the filter member is configured so as to be receivable in a filter cover arranged to attach externally to an air outlet of a fan or room ventilator.

3. A filter member as claimed in claim 1 , wherein the filter member is configured so as to be received in a fan or room ventilator between at least one rotatable fan member and an air outlet.

4. A filter member as claimed in any one of claims 1 to 3, comprising at least one rim portion disposed adjacent a peripheral edge of the filter member. 5. A filter member as claimed in claim 4, comprising first and second oppositely disposed rim portions.

6. A filter member as claimed in any one of claims 1 to 5, wherein the first filter layer includes at least one filter portion arranged to filter airborne particulate matter having a diameter of at least about 0.3 microns and at least one support portion arranged to provide structural support to the at least one filter portion.

7. A filter member as claimed in claim 6, wherein the at least one filter portion includes polypropylene melt-blown fibre material.

8. A filter member as claimed in claim 6 or claim 7, wherein the at least one filter portion includes a web of filter material folded into pleats.

9. A filter member as claimed in any one of claims 6 to 8, wherein the at least one filter portion includes glass or synthetic fibre material. 10. A filter member as claimed in any one of claims 6 to 9, wherein the at least one support portion includes polyester and rayon material

1 1. A filter member as claimed in any one of claims 6 to 10, wherein the first and second filter portions are disposed in alternate transverse layers in the first filter layer.

12. A filter member as claimed in any one of the preceding claims, wherein the filter member is substantially flat.

13. A filter member as claimed in any one of the preceding claims, wherein the second filter layer includes activated carbon material.

14. A filter member as claimed in claim 13, wherein the second filter layer includes a mesh layer of polyester material impregnated with activated carbon. 15. A filter member as claimed in any one of the preceding claims, wherein the at least one second filter layer includes nonwoven activated carbon, open cell activated carbon foam or honeycomb type activated carbon material.

16. A filter member as claimed in any one of the preceding claims, wherein the filter member has a substantially circular or rectangular cross sectional shape.

17. A filter member as claimed in any one of the preceding claims, wherein the filter member has a width substantially the same as the width of the air outlet of the fan or room ventilator with which the filter member is to be used.

20. A filter device comprising:

a filter member as claimed in any one of the preceding claims;

a filter cover arranged to receive the filter member and attach externally to an air outlet of a fan or room ventilator of the type including at least one rotatable fan member, the filter cover including:

a permeable portion disposed adjacent the filter member when the filter member is received in the filter cover, the permeable portion arranged to permit substantially unrestricted airflow through the permeable portion; and

wherein the filter member^' is shaped and the filter cover is arranged such that 5 substantially all air moved by the fan is directed through the filter member when the filter member is received in the filter cover and the filter cover is attached externally to the fan or room ventilator.

21. A filter device as claimed in claim 20, wherein the substantially impermeable i o retaining portion comprises a band portion and a resilient portion arranged to facilitate attachment of the cover member to the fan, the band portion extending between the permeable portion and the resilient portion.

22. A filter device as claimed in claim 21 , wherein the resilient portion includes a 15 circumferential elastic portion disposed adjacent a free circumferential edge of the substantially impermeable retaining portion.

23. A fan comprising:

a housing portion connected to a protective cage portion so as to define an 20 internal cavity for housing at least one rotatable fan member; and

at least one filter member as claimed in any one of the preceding claims, the filter member disposed in the cavity between the at least one rotatable fan member and the protective cage.

25 24. A room ventilator comprising:

a housing having a permeable inlet and a permeable outlet;

at least one rotatable fan member mounted in the housing;

at least one a filter member as claimed in any one of the preceding claims, the room ventilator arranged such that the housing is retainable relative to a 30 window with the permeable inlet facing outwardly of the room and the permeable outlet facing inwardly of the room; and

the room ventilator arranged such that at least one rotatable fan member causes air to flow from the permeable inlet to the permeable outlet through the at least one filter member.

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25. A room ventilator as claimed in claim 24, wherein the filter member is disposed in the housing between the at least one rotatable fan member and the permeable outlet.

26. A room ventilator as claimed in claim 24, wherein the filter member is configured so as to be receivable in a filter cover arranged to attach to the room ventilator over the permeable outlet.

27. A room ventilator as claimed in any one of claims 24 to 26, wherein the housing is engageable with and disengageable from a stand so as to thereby provide a free standing room ventilator.