Ultrasonic atomisers have long been used to vapourise liquid fragrance compositions to freshen the air. They offer advantages over alternative methods (heated liquid electricals/candles for example) in that they do not require heating to operate. Which means they are safer, no naked flames and they use much less power than heated emanators, so they can be readily run with batteries for extended periods. This gives them flexibility of placement.

Such devices usually comprise a vibrating plate, a source of power, a reservoir of liquid fragrance and a means to transport the liquid fragrance to the plate for atomisation.

Examples of such devices in the prior art are included in documents JP3342095, US2008041972 Al, US2001042794A, US6446880 Bl and US6341732 Bl. The contents of which are hereby incorporated by reference into the present application.

Problems associated with these devices include obtaining consistent and reliable emanation and leaks. The contact between the piezo vibrating plate and the source of the liquid fragrance must be in finely balanced to allow for successful operation. Drop out and un-atomised spray of the liquids is common when the plates are not vibrating optimally.

Summary of the invention

An atomiser for dispensing a fragrance; the atomiser comprising a) an outer housing;

b) an orifice plate and piezo electric element;

c) a liquid reservoir, comprising a liquid to be atomised, the liquid comprising a fragrance composition and a carrier solvent; and

d) a liquid transport member wherein the liquid transport member extends from within the liquid reservoir to abut the orifice plate; and wherein the liquid transport member is substantially contained within the liquid reservoir and both the liquid transport member and liquid reservoir are readily detachable together from the atomiser; and wherein the carrier solvent comprises at least 50% by weight, branched chain alkanes.

Description

Piezo devices and systems for fragrancing the air in the art suffer from a variety of inefficiencies. Poorly aligned interfaces between the vibrating plates and the source of liquid fragrance to be atomised cause many difficulties. As does the rate at which fluid is delivered to the plate from the wick. A low fluid delivery rate means poor fragrance release rate and a high delivery rate gives rise to spray formation (incomplete atomisation). It has surprisingly been found that a lot of these issues can be resolved by the use of particular solvents as carrier fluids in the fragrancing liquids to be atomised. Liquid fragrance compositions containing high concentrations of branched or so-alkanes seem to provide excellent atomising properties and delivery properties. Low levels of spray (large particle sizes) and very low residues (particle drop out) are obtained when high levels of branched alkane solvents are used in the carrier liquids.

Fragrance compositions containing at least 50% branched alkanes in the carrier solvent have superior dispensing characteristics in ultrasonic atomising dispensers.

For the purposes of the present invention branched alkanes means any alkanes that are not completely linear. They may have single or multiple branching. Preferred alkanes are /so-alkanes.

Preferably the branched alkanes of the present invention comprise mixtures (or single compounds) with between 11 and 16 carbon atoms.

Commercial examples of useful branched alkanes include the Isopar™ class of products from Exxon mobile. A particularly advantageous branched chain solvent for use in the present invention is Isopar M™ Preferably the branched alkane carrier solvent has a boiling point of between 240 and 270 °C, preferably between 250 and 260 degrees °C and most preferably between 252 and 258 degrees °C.

Preferably the branched alkane carrier solvent has a molecular weight of between 160 and 200, preferably between 185 and 195 and most preferably 188.

Preferably the carrier solvent consists substantially of branched chain alkanes.

The fragrancing liquid of the present invention is preferably composed of a) Fragrance composition 2-25% by weight and

b) Carrier solvent 75 -98% by weight Preferably the liquid comprises at least 5% by weight of fragrance composition, preferably at least 10% by weight fragrance composition and most preferably at least 15% by weight fragrance composition.

Preferably the liquid comprises at least 50% by weight carrier solvent, preferably at least 75%, more preferably at least 80% and most preferably at least 85% by weight of carrier solvent.

The liquid transport member is a key part of the device. For successful operation the liquid transport member and orifice plate have to interact successfully. The liquid transport member may be made from any suitable material. Preferably the liquid transport member moves liquid from the reservoir to the plate by wicking or capillary action.

Preferably the liquid transport member of the present invention is a wick comprising paper, cotton, nylon, or polypropylene. Most preferably the wick will be formed from polypropylene.

Preferably the wick is between 4cm and 14 cm in length, more preferably between 5cm and 12 cm and most preferably between 6 and 10 cm in length. Preferably the atomiser is powered by battery. Preferably the atomiser comprises at least one battery, and more preferably at least two batteries.

The atomiser may require between 1 and 12 volts to operate, more preferably 3- 4.5 volts. The atomiser may be provided with control circuitry to allow for regular activation of the device over time. Settings may be provided to control length of activation and time between activations. This allows the device to be left in the home or office and provide a constant release of fragrance over many weeks and days.

Activations of the orifice plate to release atomised liquid fragrance composition may last between 1 second and 30 seconds, preferably between 2 seconds and 15 seconds, more preferably between 3 seconds and 10 seconds.

Timing between activations may be between 2 mins and 30 mins, preferably between 5 mins and 20 mins, most preferably between 7 mins and 15 mins.

The skilled person can vary these parameters depending on the intensity of the fragrance desired, strength of fragrance used and concentration of the fragrance composition within the fragrance liquid.

A second aspect to the present invention involves a method of fragrancing the air comprising activating the device of the first aspect of the invention.

This may be manually or automatically by setting up dispensing parameters. Automatic dispensing will require control circuits to activate the device at intervals.

A third aspect of the present invention is a separate refill of fragrance suitable for use as the liquid reservoir with the device of the first aspect of the invention.

This will comprise a container suitable for standalone sale.

Preferably this will be a small flask or bottle. This may be made of any material.

Preferably this will be made of glass or plastic. This will preferably be readily insertable into the atomiser device of the present invention. This should be such that the user may easily remove empty refills. The user may also decide to replace a partially used refill for a refill of a differing fragrance if desired. The fragrance refill will comprise

1) a liquid; further comprising A fragrance composition and a carrier solvent; and

2) a wick, extending from inside the refill to the outside; wherein the carrier solvent comprises at least 50% by weight of branched alkanes.

Including the wick with the refills prevents the mixing of fragrances in the wick. A rapid fragrance change can be carried out without blending different fragrances.

Wicks can get clogged in time. Using a new wick with each refill prevents this from happening.

The refill may comprises at least 5% by weight of fragrance composition, preferably at least 10% by weight fragrance composition and most preferably at least 15% by weight fragrance composition.

The refill liquid may comprise at least 60% by weight carrier solvent, preferably at least 75%, more preferably at least 80% and most preferably at least 85% by weight of carrier solvent.

The carrier solvent may comprises at least 60% by weight of branched alkanes, preferably at least 70% by weight of branched alkanes and most preferably at least 90% by weight branched alkanes.

The carrier solvent of the refill may consist entirely of branched-alkanes.

The branched alkane carrier solvent may have a boiling point of between 240 and 270 °C, preferably between 250 and 260 °C and most preferably between 252 and 258 degrees °C. The branched alkane carrier solvent may have a molecular weight of between 170 and 200, preferably between 185 and 195 and most preferably 188.

A particularly preferred refill contains:

15% by weight of fragrance composition; and 85% by weight of a branched alkane solvent.

More preferably the branched alkane solvent comprises Isopar-M ^® .

A device comprising the refill above and a polypropylene wick has been shown to yield excellent fragrance dispersion characteristics with virtually no residues remaining.