DUAL-PURPOSE DEVICE

This invention relates to wick-based devices for disseminating volatile liquids into the atmosphere.

Wick-based devices for disseminating volatile liquids, such as fragrances, malodour counteractants, disinfectants, insecticides, fungicides, mildewicides and the like are well known. They typically comprise a reservoir of liquid and a wick of porous material, generally cylindrical, which protrudes from the reservoir, with a lower end in contact with the liquid and an upper end exposed to the atmosphere, thus transferring the liquid to the atmosphere. In very simple devices, such as many commercially-available air fresheners, this comprises the entire operating components and dissemination is by unaided evaporation only. However, with the availability of small fans and blowers of the type used to cool laptop computers and of relatively cheap heating elements, one or more of these have been used in conjunction with wicks to augment the dissemination.

An increasing problem is the presence in the atmosphere of particulate matter, such as dust, human and animal tissue and detrius, pollens, and the like. These can cause allergic reactions in many people. The atmosphere can be subjected to filtering by causing the air to flow through a filter. Such filters can be very efficient, but usually at the cost of restricted airflow (generally, the more efficient the filter, the smaller the porosity).

It is often desirable to perform both the dissemination of volatile liquid into an atmosphere and the filtering of the atmosphere at the same time. This can be done, and there have been proposed apparatus comprising dissemination elements, such as wicks, along with filters. However, these have not proved successful, as the filter tends to block the airflow to the wick, thus reducing the efficiency of the dissemination.

It has now been found that it is possible not only to filter the atmosphere in an enclosed space, such as a room, but also to disseminate it at the same time, using not only the same apparatus, but also the same element. There is therefore provided a device adapted

simultaneously to filter particulate matter from an atmosphere and disseminate a desirable volatile liquid into the atmosphere, comprising a generator of forced air flow, a porous wick contacting the liquid in a reservoir and conveying it to a dissemination surface so arranged and configured as to encounter substantially all of the air flow and simultaneously to disseminate liquid and filter particulate matter from the air.

There is also provided a method of simultaneously filtering particulate matter from an atmosphere and disseminating a desirable volatile liquid into the atmosphere, comprising providing a source of volatile liquid and means for conveying this liquid to a liquid dissemination element, which liquid dissemination element is adapted both to filter particulate matter and disseminate liquid, and directing a forced air flow from the atmosphere to the liquid dissemination element, which element is so configured as to encounter substantially all of the air flow.

Porous wicks that are capable of conveying liquid from a reservoir are well known to the art, and have been used for many years as components for air fresheners. Any of the known types may be used in the device. They may be made of any suitable materials that are porous or fibrous, or that function by means of capillary action. Examples include materials such as polymers, natural materials of vegetable or mineral origin, such as cellulosic materials, sintered metals and ceramics.

The wick is in liquid transfer contact with a dissemination element. While the wick and the dissemination surface may be separate components joined by any convenient means that ensures liquid transfer contact, in a particular embodiment, the dissemination element and the wick are formed from a single piece of any suitable porous or fibrous material. Ideally, such material should be self-supporting, that is, it has sufficient inherent strength and rigidity so that auxiliary support means is not required. Typical examples of such self- supporting materials are certain commercially-available porous plastics materials (such as Porex™) and fibrous materials, such as Filtrona™ materials.

The basis of the device is that the dissemination surface, wetted as it is by liquid from the reservoir, acts as both filter and dissemination surface. The wetted surface is very efficient

at trapping particles, much more so than most dry filters. The assurance of an adequate degree of wetting is well within the skill of the art and requires only routine experimentation.

The configuration of the dissemination surface may be any that allows it to contact substantially ail of the air flow. By "substantially all" is meant sufficient air flow to ensure that essentially all atmospheric particulate matter entrained in the air flow is trapped by the dissemination surface. This is achieved by ensuring that the air flow has no direct path past the surface.

The skilled person will realise that there are many possibilities of realising this. In general, it means that, if the air flow is entrained through a channel en route to the dissemination element, that dissemination element must extend completely across the channel. It may be, for example, a porous or fibrous sheet of material, in liquid transfer contact with the wick in the reservoir. Such sheets may be made of any suitable material, such as cellulosic materials such as paper and cardboard, polymeric materials, and sintered porous ceramics and metals. These may be self-supporting, or supported in suitable frames.

In a particular embodiment, the dissemination element has the form of at least two essentially parallel upright plates, each plate being broken by apertures that allow the air flow to pass through. The apertures in the various plates are arranged so that they are not aligned with each other, and such that there is no straight-through path for the air-flow. The air-flow is thus forced to change course repeatedly, this bringing it into contact with a substantial part of the exposed surfaces of the plates and catching essentially all of any airborne particulates.

The apertures may be holes in the plates, or they may extent the entire height of the plates, so that each plate has the form of a comb with very wide teeth, the plates being arranged such that the teeth of the comb are staggered with respect to each other, such that there is no straight-through path for the air flow. Such an element may be self-supporting and formed from any suitable material, such as porous plastics materials (such as Porex™) and fibrous materials, such as Filtrona™ materials, as hereinabove mentioned In a further

embodiment, the wick and the dissemination element hereinabove described are formed from a single piece of self-supporting material.

One of the advantages of this embodiment is that the reservoir, liquid, wick and dissemination element can be supplied as a single unit, which can be made available separately as a refill. Thus refilling and renewing the filter element can be achieved in one simple operation.

The remainder of the device may be made of conventional materials and components. The fan may by any suitable small fan or blower and any housing or container for the device may be made of any desired materials or in any shape.

The device is easily and inexpensively made from known components and materials, and is effective in use.

The invention is further described with reference to the drawings, which depict preferred embodiments by way of example only, and which are not intended to be in any way limiting on the scope of the invention.

Figure 1 is a schematic, perspective part-section view of an air freshener.

Figure 2 is a schematic, exploded view of a reservoir/wick combination for use in the device of Figure 1.

Figure 3 is a transverse cross-section of one part of a further embodiment of the invention.

In Figure 1, an air freshener has a housing 1, in which is housed a centrifugal blower 2, rotated by an electric motor 3 and blowing through an outlet 4. The blower draws air into the housing through a series of vents 5 in an extension 6 of the housing 1. Within this extension is positioned a liquid dissemination element 7, which will be further described hereinunder with respect to Figure 2. This dissemination element is formed as a single unit with a wick 8, which is immersed in fragrance in a reservoir 9.

In Figure 2, the dissemination element 7 can be seen to have the form of two broad-toothed combs, the combs being arranged such that the teeth are staggered, thus not permitting any air flow to take a direct path through the element. The wick 8 is formed with the dissemination element as a single piece of Filtrona™ fibrous material, the wick being inserted into the reservoir 9. It is held in place by a supporting member 10 that fits into a neck of the reservoir 9. The components of Figure 2 can be provided as a single unit to refill a device whose liquid is exhausted or whose filtering capacity has been considerably reduced or exhausted.

In operation, the blower 2 draws in atmospheric air through the vents 5. The air flow encounters the dissemination element, whose surface is wetted by fragrance from the reservoir 9 and which also acts as a filter for atmospheric particulate matter. It is assisted in this by the staggered design of the combs, which ensure that substantially all of the air flow contacts a surface of the comb. When the air flow reaches an inlet 11 of the blower 2, it has been cleansed of substantially all airborne particulate matter and has received a charge of fragrance. It is then blown by the blower through the outlet 4 and into the atmosphere.

Figure 3 depicts an embodiment in which a blower 2 blows air over a dissemination element 7, as opposed to the drawing in of air as in Figure 1.

The skilled person will comprehend that there are many other possible variants of this invention, which lie within the scope of this invention and which can be realised by the simple, non-inventive exercise of the skill of the art.