WO1999030087A1

WO1999030087A1 - Therapeutic air vent filter screen

Info

Publication number: WO1999030087A1
Application number: PCT/AU1998/001016
Authority: WO
Inventors: David Andrew West
Original assignee: David Andrew West
Priority date: 1997-12-09
Filing date: 1998-12-09
Publication date: 1999-06-17
Also published as: WO1999030087A8

Abstract

A therapeutic air vent filter screen (1) for use with air inlet and outlet vents, particularly in air conditioned rooms. The air vent filter screen consists of non-woven fibrous material (6) to cover a vent (2). A light oil is applied to the material to increase its filtering capacity. The light oil also acts as a carrier for a therapeutic agent applied to the material. The therapeutic agent may be an aromatherapeutic oil, a pharmaceutical agent, a disinfectant or an insect repellent. Air passing through the filter screen is both filtered and medicated by the addition of the therapeutic agent.

Description

TITLE "THERAPEUTIC AIR VENT FILTER SCREEN"

FIELD OF THE INVENTION THIS INVENTION relates to a filter screen for an air vent. In particular, it relates to a filter screen that may be impregnated with a carrier and a therapeutic agent to improve the quality of air passing through the vent.

BACKGROUND TO THE INVENTION

During mechanical ventilation of buildings, air is delivered into internal spaces by passage through vents. Air passing through these vents usually carries particles of dust, lint, pollen, spores, mites and other matter suspended in the air flow. These particles may act as provocative agents to incite episodes of asthma, hayfever or other allergies.

Filters are widely use for purifying fluids and various types have been described for use with air. US Patent No 2,243,637 discloses an air conditioner for industrial application in which an air filter element is installed in the circulatory system. The filter simply acts as a permeable barrier to the circulating air.

US Patent No 3, 572, 243 describes a device for delivery of fan-forced air through a filter and across an opening such as a door or window. The primary purpose of the air "curtain" is to prevent ingress of dust and insects into a building. The air provided, however, is simply passed through a dry filter with no other enhancement of its quality.

International Application No PCT/AU94/00690 describes a filter system for an evaporative cooler. Air passes through a dry filter and a wettable filter pad before discharge into a room. This application is restricted to evaporative coolers and although it cools and filters air, the system does not otherwise enhance it.

The use of filters is also known in air conditioning systems that draw air from outside a conditioned chamber and also those systems that recycle air from the chamber. These filters, however, are usually comprised simply of a filter element of a fibrous or paper type which mechanically filter the air for an entire building. It would be of advantage to provide a filter for use with an air vent which, as well as filtering air passing through the filter, also enhanced the air by adding at least one therapeutic agent to it. The use of such a filter would allow individual treatment of the air in one room or treatment of a group of rooms independently of the rest of a building. This may be particularly important in the light of increasing statutory requirements for healthy workplace environments. Empirical evidence strongly supports the theory that enhancing the quality of the air in a workplace causes a direct increase in productivity. This increased productivity results in distinct economic advantage to employers.

A further issue to be considered, particularly in relation to air conditioning systems, is legionnaire's disease. The Legionella organism has been found to successfully colonise air conditioning cooling towers with subsequent distribution through ducting. Any filter system installed between the cooling system and recipient of conditioned air can be of assistance in decreasing the risk of disease. This is particularly so if that system is able to trap bacterial particles as well as exert an antibacterial effect. In this specification, therapeutic agent includes pharmaceutical agents, aromatherapy oils, antiseptic agents and insect repellents.

OBJECT OF THE INVENTION It is an object of the present invention to provide a filter screen for an air vent, wherein the filter screen both filters the air passing through it and adds a therapeutic agent to that air.

It is a further object to provide a means of attaching such a filter to or near an air vent.

Further objects will be evident from the following description. DISCLOSURE OF THE INVENTION In one form, although it need not be the only or indeed the broadest form, the invention resides in a therapeutic air vent filter screen comprising: a non-woven fibrous material which is dimensioned to cover a vent through which air flows; attachment means for maintaining the material in position relative to the air vent such that air passing through the air vent is filtered; a viscous carrier applied to the material; and a therapeutic agent associated with the carrier and of a volatile nature such that the therapeutic agent permeates air passing through the vent. The inventor has found that use of the therapeutic air vent filter screen to control the local environment leads to surprising degree of improvement in air quality. This is particularly the case in air conditioned rooms where pressurisation of the room relative to outside air pressure leads to little intrusion of untreated air. Application of the invention at the air vent level gives unexpected advantages in quality enhancement over and above other forms of air circulation/filtration combinations.

The material is suitably selected from one or more of Rayon™, polyester, wool and hemp.

Suitably, the carrier is a light natural oil. Preferably, the carrier is selected from one or more of tea tree oil, almond oil, hemp oil and neem oil. Suitably, the carrier is impregnated into the material.

Preferably, the therapeutic agent is an aromatherapeutic oil. Alternatively, the therapeutic agent may be a pharmaceutical agent. The pharmaceutical agent may be salbutamol (ventolin™). Further alternatively, the therapeutic agent may be an insect repellent. Preferably, the therapeutic agent has disinfectant properties. The therapeutic agent may comprise two or more of a pharmaceutical agent, an agent having an aromatherapeutic effect, an agent having disinfectant properties and an insect repellent. Suitably, the therapeutic air vent filter screen further comprises a colour additive to indicate the presence of the therapeutic agent. Alternatively, the therapeutic air vent filter screen may include a chemical indicator for indicating a time for replacing the therapeutic air vent filter screen.

Suitably, the attachment means comprises a resilient band attached to the material and expandable so as to engage an air vent and thereby retain the material in position across air flow from the vent.

The attachment means may further comprise an attachment frame that is attachable to or near the air vent and projects from the air vent so that the resilient band can be engaged with the frame. In a further embodiment, the attachment means comprises a frame support to removably receive at least one cartridge, said at least one cartridge confining the non-woven fibrous material.

In yet a further embodiment, the attachment means comprises hook and loop fasteners (Velcro™) for retention of the non- woven fibrous material in position in relation to the vent.

In yet a further embodiment, the attachment means comprises a plurality of hook projections secured to a surface adjacent the air vent and engagable with the material.

If preferred, the attachment means may further comprise an auxiliary fan to augment the flow of air through the non-woven fibrous material.

In another form, a wad treated with one or more therapeutic agents is retained in a wad retaining means joined to the non-woven fibrous material. The wad retaining means is preferably a loop or pocket. The wad is preferably formed from a non-woven cellulose-based fibre material.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional schematic view of a ceiling with an air vent having an air vent filter screen attached. FIG. 2 is an exploded sectional view of a ceiling with an air vent filter screen and attachment frame. FIG. 3 is an exploded sectional view of a ceiling with an air vent and attachment frame with hook fasteners.

FIG. 4 is a plan view of a filter fibre mounting frame and filter fibre locking frame. FIG. 5 is a cross-sectional view of the locking frame of FIG 4 located in the mounting frame.

FIG. 6 is an exploded schematic view of a frame support with filter cartridges and an auxiliary fan.

FIG. 7 is a schematic sectional view of a frame support located above a ceiling air vent.

FIG. 8 is a sectional view of the filter showing air flow paths and a wad retaining loop.

DETAILED DESCRIPTION OF THE DRAWINGS In the drawings, like reference numerals refer to like parts. Referring to FIG. 1 , there is shown an air vent filter screen 1 located adjacent to an air vent 2 which penetrates ceiling 3. Ducting 4 channels air flow 5 through air vent 2 and across air vent filter screen 1. Air vent filter screen 1 is composed of a non-woven fibrous material 6 such that air flow 5 must follow a tortuous track in penetrating the air vent filter screen 1. As a result of following this tortuous track, particles of matter entrained in air flow 5 contact fibres of material 6 and are retained by the filter screen 1.

To further enhance the effect, the material 6 is impregnated or coated with a light oil, such as tea tree oil (melaleuca alternifolia). Tea tree oil has a double effect on the effectiveness of the filter. Firstly, it has an antimicrobial action to disinfect the air passing through the filter screen 1. Secondly, the oil aids in trapping dust from the air into the filter screen 1.

Although tea tree oil is preferred, it will be appreciated that other light oils, such as hemp oil, neem oil, wheat germ, jojoba, grape seed or almond oil could be used. The inventors have found that the filter material provides a suitable matrix for carrying essential oils used in aromatherapy. Essential oils are volatile oils generally derived from the leaves, stems, flowers or twigs of plants. Chemically, they are principally terpenes (hydrocarbons) but many other types occur. The majority of essential oils have a low oral and dermal toxicity. In a preferred embodiment, the filter is sprayed with a carrier in the form of a light oil, such as tea tree oil and additionally an aromatherapy blend of essential oils is added. The actual blend of essential oils is a matter of taste for the user. Persons having knowledge of aromatherapy will know that a large number of blends are possible from the 36 essential oils.

Alternatively, the therapeutic agent may be a pharmaceutical agent, such as ventolin™ for medication of the environment in a room. Of course, the invention is not limited to ventolin™ but could be used with any medication that may be released into the environment.

The therapeutic agent may be an insect repellent for the purposes of treating the air to avoid the presence of biting insects, such as mosquitos. This may be of particular importance in areas that suffer from arthropod borne diseases, such as Ross River Fever and Dengue Fever.

Because the preferred therapeutic agents evaporate over time, the filter has an effective life limited by the evaporation rate of the agents and the quantity of agents applied to the material. In one embodiment, this lifetime feature is enhanced by treating the therapeutic agent with a colour additive that indicates the presence of the therapeutic agent. When the colour is gone from the filter, it indicates that the therapeutic agent has evaporated and the therapeutic value is negligible. This indicates to the user that it is time to replace the filter. Alternatively, a separate chemical indicator can be used to indicate the time to change the filter. The chemical indicator could be linked directly to duration of use or to dust captured.

FIG. 2 shows a sectional view of an air vent 2 penetrating ceiling 3 and connected to ducting 4. An attachment frame 7 has a base 8 and lip 9. The base 8 can be attached to ceiling 3 by any appropriate means such as screw, adhesive or other fastening device. Material 6 is connected to a resilient band 10. To attach filter screen 1 to the air vent outlet, resilient band 10 may be expanded and located around lip 9 and then released so that it contracts to a tight retention fit. To replace filter screen 1 , it is simply a matter of reversing the above steps to remove an exhausted filter and then locate a replacement filter.

FIG. 3 shows an alternative retention means in which material 6 is engaged with hook projections 11 located on attachment frame 12. In a further embodiment, which is not shown, material 6 may be attachable to attachment frame 12 by means of hook and loop fasteners (Velcro™) wherein the hook portion of the fasteners are attached to either the attachment frame or filter screen and the loop portion is attached to the other.

FIG. 4 shows a further embodiment of an attachment means for use with the air vent of the invention. A filter fibre mounting frame 13 has a series of projecting teeth 14. The mounting frame 13 is attached to a ceiling or wall around an air vent (not shown). Non-woven fibrous material is placed so that its fibres engage the teeth 14 and a locking frame 15 is then located inside filter fibre mounting frame 13 and is retained in position either by a friction fit or positive engagement means, such as a screw, nut or adhesive.

FIG. 5 is a cross-sectional view of one edge of the attachment means of FIG. 4 when assembled. Material 6 is engaged with tooth 14 and locking frame 15 is pushed into contact with filter fibre mounting frame 13. FIG. 6 is a schematic view of a frame support 16 with slots

17 to receive cartridges 18. Each of the cartridges 18 contains non- woven fibrous material 19. The frame support 16 is attachable to ceiling 3 so as to surround the air vent 2 which is connected to ducting 4.

This embodiment allows easy replacement of expired cartridges. It also permits the application of different therapeutic agents to different cartridges in the frame support. A combination of therapeutic agents may then be added to the air to provide a desired result.

The assembly further includes a removable housing 20 which supports an auxiliary fan 21 to augment the flow of air through the frame support 16 when fully assembled. The fan 21 is not essential but may be required when the thickness and type of cartridges 18 used restrict the flow of air to such an extent that ventilation is significantly impeded. Alternatively, the use of the fan 21 may be required in ventilation systems in which the pressure of air delivery is decreased due to the inherent characteristics of the system or due to deterioration and subsequent leakage in the air ducting system.

FIG. 7 shows a view of a filter support frame 22 which is located between an air vent 23 and ceiling or wall 24. This arrangement presents a less obtrusive end result as the only projection from the ceiling or wall 24 is flange 25. FIG. 8 shows the tortuous air path followed by air flow 5 as it traverses material 6. In a further embodiment, therapeutic agents may be applied to a wad which is held by a wad retaining means in the air flow. Such a wad retaining means is shown in FIG 8. Loop 26 is stitched to material 6 so as to ensure that air flows past and through a wad (not shown) inserted in loop 26. The wad (not shown) is suitably formed from a non-woven cellulose-based fibre.

Throughout the specification the aim has been to describe the preferred embodiments of the invention without limiting the invention to any one embodiment or specific collection of features.

Claims

1. A therapeutic air vent filter screen comprising: a non-woven fibrous material which is dimensioned to cover a vent through which air flows; attachment means for maintaining the material in position relative to the air vent such that air passing through the air vent is filtered; a viscous carrier applied to the material; and a therapeutic agent associated with the carrier and of a volatile nature such that the therapeutic agent permeates air passing through the vent.

2. The therapeutic air vent filter screen as claimed in Claim 1 wherein the material comprises one or more of RayonΓäó, polyester, wool and hemp.

3. The therapeutic air vent filter screen as claimed in Claim 1 wherein the carrier is one or more light natural oils selected from a group including tea tree oil, almond oil, hemp oil and neem oil.

4. The therapeutic air vent filter screen as claimed in Claim 1 wherein the therapeutic agent is one or more of a pharmaceutical agent, an agent having an aromatherapeutic effect, an agent having disinfectant properties and an insect repellent.

5. The therapeutic air vent filter screen as claimed in Claim 1 wherein the therapeutic agent is salbutamol (ventolinΓäó).

6. The therapeutic air vent filter screen as claimed in Claim 1 further comprising a colour additive for indicating the presence of the therapeutic agent.

7. The therapeutic air vent filter screen as claimed in Claim 1 further comprising a chemical indicator for indicating a time for replacing the therapeutic air vent filter screen.

8. The therapeutic air vent filter screen as claimed in Claim 1 wherein the attachment means comprises a resilient band attached to the material wherein the resilient band is expandable to engage an air vent, thereby retaining the material in position across air flow from the vent.

9. The therapeutic air vent filter screen as claimed in Claim 1 wherein the attachment means includes an attachment frame located in the vicinity of the air vent and engagable by a resilient band attached to the material.

10. The therapeutic air vent filter screen as claimed in Claim 1 wherein the attachment means comprises a plurality of hook projections secured to a surface adjacent the air vent and engagable with the material.

11. The therapeutic air vent filter screen as claimed in Claim 1 wherein the attachment means comprises a frame support to removably receive at least one cartridge, wherein said cartridge confines the non- woven fibrous material.

12. The therapeutic air vent filter screen as claimed in Claim 1 wherein the attachment means further comprises an auxiliary fan, wherein said auxiliary fan augments the flow of air through the non-woven fibrous material.

13. The therapeutic air vent filter screen as claimed in Claim 1 further comprising a wad retaining means for retaining a wad treated with one or more therapeutic agents.

14. The therapeutic air vent filter screen as claimed in Claim 13 wherein the wad retaining means is a loop or pocket joined to the material.

15. The therapeutic air vent filter screen as claimed in Claim 13 wherein the wad is formed from a non-woven, cellulose-based fibre.