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Title:
VOLATILE LIQUID EMANATION DEVICE WITH CAPILLARY
Document Type and Number:
WIPO Patent Application WO/2011/161462
Kind Code:
A1
Abstract:
A passive emanation device for emanating a volatile liquid is described wherein the volatile liquid contains one or more active materials wherein the active material comprises at least one of: a fragrance: an insecticide; a fungicide; a pesticide; a sanitising material; and/or a pharmaceutical; and wherein the passive emanation device comprises: a housing: a volatile liquid reservoir; one or more capillary tubes in fluid communication with the reservoir at one end thereof wherein said one or more capillary tubes are in non-vaived fluid communication with the reservoir; a nozzle located at the end of the or each capillary tube(s) remote from the reservoir wherein the or each nozzle is in non-vaived fluid communication with the or each capillary tube{s); and an emanation substrate; wherein the housing is arranged to support the reservoir, capillary tube and nozzle in spatial arrangement over the emanation substrate.

Inventors:
KULKE, Torsten (Symrise AG, Mühlenfeldstraße 1, Holzminden, 37603, DE)
STEPHENSON, Helen (Reckitt Benckiser, Dansom LaneHull, Yorkshire HU8 7DS, GB)
WALSH, Steve (Reckitt Benckiser, Dansom LaneHull, Yorkshire HU8 7DS, GB)
WOODMAN, Cheryl (Reckitt Benckiser, Dansom LaneHull, Yorkshire HU8 7DS, GB)
Application Number:
GB2011/051188
Publication Date:
December 29, 2011
Filing Date:
June 24, 2011
Export Citation:
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Assignee:
RECKITT & COLMAN (OVERSEAS) LIMITED (103-105 Bath Road, Slough, Berkshire SL1 3UH, GB)
KULKE, Torsten (Symrise AG, Mühlenfeldstraße 1, Holzminden, 37603, DE)
STEPHENSON, Helen (Reckitt Benckiser, Dansom LaneHull, Yorkshire HU8 7DS, GB)
WALSH, Steve (Reckitt Benckiser, Dansom LaneHull, Yorkshire HU8 7DS, GB)
WOODMAN, Cheryl (Reckitt Benckiser, Dansom LaneHull, Yorkshire HU8 7DS, GB)
International Classes:
A61L9/12; A01M1/20
Domestic Patent References:
2007-11-01
2004-11-04
Foreign References:
GB2357973A2001-07-11
US3456694A1969-07-22
Other References:
None
Attorney, Agent or Firm:
CARLIN, Robert G. et al. (Reckitt Benckiser Corporate Services Limited, Legal Department - Patents GroupDansom Lane, Hull Yorkshire HU15 1PT, GB)
Download PDF:
Claims:
1. A passive emanation device for emanating a volatile liquid containing one or more active materials wherein the active material comprises at least one of: a Fragrance; an insecticide; a fungicide; a pesticide; a sanitising material; and/or a pharmaceutical;

and wherein the-fsassive emanation device comprises:

a housing;

a volatile liquid reservoir;

one or more capiiiary tubes in fluid communication with the reservoir at one end thereof wherein said one or more capiiiary tubes are in non-va!ved fluid communication with the reservoir;

a nozzle located at tie end of the or each capillary tube(s) remote from the reservoir wherein the or each nozzle is in non-vafved fluid communication with the or each capiiiary tube(s); and an emanation substrate;

wherein the housing is arranged to support the reservoir, capillary tube(s) and nozzle(s) in spatial arrangement over the emanation substrate.

2. A device according to claim 1 , wherein the device is configured to allow liquid on to the emanation substrate at a non-valved flow rate of between substantially 0.1 - 500,</l/hr, and preferably between substantially 20 - 40pL/hr, and most preferably between substantially 26 - 34wUbr.

3. A device according to claim 1 or claim 2t wherein the device is configured to allow the mass of each liquid droplet to be between substantially 0.1 - 5Q0mg, and preferably between substantially 0.5 - 70mg.

4. A device- according to any preceding claim, wherein the reservoir is provided with a vent hole,

5. A device- according to claim 4, wherein the vent hole is covered by a re-sea!abie sealing member which can be opened arid re-sealed.

6. A device according to any preceding claim, wherein the reservoir is sized to retain a volume of volatile liquid between substantially 0.1 - 500ml, and preferably between substantially 10 - 40ml,

7. A device according to any preceding claim, wherein the reservoir is shaped such that the volatile liquid head height therewith in is between substantially 0.1 - 100cm, and preferably between substantially 3 - 10cm, 12337P1

8. A device according to any preceding claim , wherein the reservoir is substantially cylindrically shaped and have a diameter of between substantially 1 - 50cm , but preferably between substantially 4 - 8cm , and have a depth of between substantially 0.1 - 100cm . but preferably between substan tially 0.5 - 2cm. θ. A device according to any preceding claim, wherein a single capillary tube is provided .

10. A device according to any preceding claim, wherein the capillary tube{s) is/are provided with a length of between substantially 0.1 - 50cm.. and preferably with a length of between substantially 3 - 10cm.

11 . A device according to any preceding claim , wherein the capillary tube(s) is/are substantially cylindrical and provided with an internal diameter of between substantially 1 - 1000^m:, and preferably with an interna! diameter of between substantially 75 - 10Ομνη.

12. A device according to any preceding claim .. wherein the nozzle(s) is/are provided with a substantially circular exit orifice having a diameter of between substantially 0.01 - 100mm, but preferably has a diameter of between substantially 0.4— 2mm .

13. A device according to any preceding claim, wherein the emanation substrate is provided in the form of one or more of; cellulose, cardboard (pressed pulp) or fibres; porous plastic ;

graphite; ceram ic: wood ; reeds; most preferably the emanation substrate material is provided in the form of balsa wood.

14. A device according to any preceding claim , wherein the emanation substrate is pre-dosed with the volatile liquid held in the reservoir.

15. A device according to any preceding claim, wherein the housing Is provided in the form of an open framework which is configured to suspend the reservoir such that the capillary and nozzle are held directly above a substantially central point of the emanation substrate.

16. A delivery mechanism for a passive emanation device according to any preceding claim, wherein the delivery mechanism is connectable, preferably releaseably connectabie, to a housing of the passive emanation device and wherein the delivery mechanism comprises:

a volatile liquid reservoir holding s volatile liquid containing one or more active materials wherein iS3S?Pi the active material comprises at least one of: a fragrance; an insecticide.; a fungicide; a pesticide; a sanitising material: and/or a pharmaceutical:

one or more capillary tubes in fluid communication with the reservoir at one end thereof wherein said one or snore capillary tubes are in non-valved fluid communication with the reservoir;

a nozzle located at the end of the or each capillary tube(s) remote from the reservoir wherein the or each nozzle is in non-valved fluid communication with the or each capillary iube{s}.

17. A passive emanation device comprising:

a housing;

a volatile liquid reservoir holding a volatile liquid containing one or more active materials wherein the active material comprises at least one of: a fragrance; an insecticide; a fungicide; a pesticide: a sanitising material; and/or a pharmaceutical;

one or more capillary tubes in fluid communication with the reservoir at one end thereof wherein said one or more capillary tubes are in non-valved fluid communication with the reservoir;

a nozzle located at the end of the or each capillary tube(s) remote from the reservoir wherein the or each nozzle is in non-valved fluid communication with the or each capillary tube(s); and an ema ation substrate;

wherein the housing is arranged to support the reservoir, capillary tube and nozzle in spatial arrangement over the emanation substrate.

18. A mechanism or device according to either claim 16 or claim 17 respectively, wherein the volatile liquid possesses the at least one of, or more preferably two of, or most preferably all three of the following properties;

- viscosity between substantially 0.1 - 10QcP, and preferably between substantially 1 - 5cP;

- density between substantially 0.1 - 10g L, and preferably betwee substantially 0.8 - 1 ,1g/L;

- average surface tension between substantially 1 - 100fflN/m , and prefera bly between substantially 1 - SOrnNAn.

19. A method of providing a flow rate of volatile liquid between substantially 0.1 - 500/.iL/hr on to an emanation substrate, wherein the method comprises the steps of placing a device according to claim 16 in a location where emanation of the volatile liquid is desired and causing the flow of liquid from the device toward the emanation substrate.

20. A passive emanation device substantially as described herein and with reference to the drawings.

Description:
12397P1

VOLATILE LIQUID EMANATION DEVICE WITH CAPILLARY

Field of the Invention

The present invention relates to a volatile liquid emanation device wherein said volatile liqu ids comprise active components such as fragrances, insecticides, fungicides, pesticides, sanitizing materials and pharmaceuticals are provided, and particularly the present invention relates to a passive, non-powered volatile liquid emanation device.

Background

Conventional passive emanation devices for volatile liquids typically work by exposing a one side of a permeable membrane to a reservoir of the volatile liquid, in such mem rane -contai ing emanation devices, the membrane is in constant contact on one side thereof with the liquid and exposed to the external environment on its other side. The contact between the volatile liquid and membrane causes the membrane to uptake the liquid by capillary action and/or diffusion, thus permitting the emanation of the liquid by evaporation from its surface exposed to the ■environment Whilst such devices are simple to construct they contain several drawbacks, some of which are identified be!ow.

One drawback, particularly with the emanation of air fresheners is that of a phenomenon called "habituation". Habituation is when users of a continuously emanating air freshener get so used to the fragrance of the air freshener that they become unable to notice if after a period of time. This is problematic in particular with non-automated air freshening devices where the user is given no visual clues as to whether the device is emanating a fragrance or not,

A further drawback associated with devices having a membrane in constant contact with a volatile material, such as 8 volatile liquid air freshener, is the phenomena of vacuum build-up. The vacuum build-up phenomena can occur inside the housing due to the wetted membrane being unable to allow sufficient flow of air therethrough in order to equalise the drop in pressure inside the housing caused by the emanation of the volatile material This build-up phenomena can cause unacceptable performance problems with such a device from a consumer perspective.

In the field ©fair freshening it is generally preferred to use a volatile liquid fragrance/air freshener comprising several components. These components often possess different volatilities which can lead to emission problems. In devices having a membrane in constant contact with the volatile liquid, an accumulation of volatile liquid components with the lowest comparative volatilities can occur leading to an undesirable non-uniform emanation profile for the iiquid.

i 123S7P1

In either or both cases of build-up phenomena and accumulation of low volatilit -components, the evaporation rate, and thus the emanation rate, of the ' volatile liquid adopts the profile shown in

Fig. 1

Eventually the emanation rate may reach equilibrium (dashed line) where the rate of evaporation of each individual component of the volatile liquid away from the membrane su rface is equivalent to the rate of deposition due to diffusion and the device cannot maintain any further vacuum.

A further drawback with known passive volatile liquid emanators is that prolonged exposure of the volatile liquid to a wicking material, such as a membrane or the like, can cause fractionation over time due to various factors such as the ' icking material having a limited porosity affecting liquid transfer fates/evaporation rates which, in turn, can change the character and/or intensity of the volatile liquid being emanated. Changes in character of emanated volatile liquids is particularly noticeable for fragrances wherein common wicking materials cause the 'high notes' of a fragrance to be evaporated when the wicking material is first exposed to the fragrartced liquid, and the low notes' are evaporated thereafter which affects the user's experience.

Accordingly, it is an object of the present invention to provide a device that is capable of addressing the abovementioned performance drawbacks and other drawbacks that will be appreciated by a person skilled in the art.

Summary of invention

According to a first aspect of the present invention there is pfovided therefore a passive emanation device for emanating a volatile liquid containing one or more activ materials wherein

7 12397M the active material comprises at least one of: a fragrance; an insecticide; a fungicide; a pesticide; a sanitising material; and/or a pharmaceutical;

and wherein the passive emanation device comprises:

a housing;

a volatile liquid reservoir:

one or more capillary tubes in fluid communication with the reservoir at one end thereof wherein said one or more capillary tubes are in non-vaived fluid communication with the reservoir;

a nozzle Iocated at the end of the or each capillary tube(s) remote from the reservoir wherein the or each nozzle is in non-vaived fluid communication with the or each capillary tube{s) : ; and an emanation substrate;

wherein the housing is arranged to support the reservoir, capillary tube(s) and nozzle(s) in spatial arrangement over the emanation substrate.

In the context of the present invention "non-vaived" should be understood as meaning that that component of the device has no mechanical features which enable it to regulate or adjust the flow of liquid therethrough .

In the context of the present invention "passive" should be understood as meaning that that the device is operable without a power source or some other means which drives the emanation of the volatile liquid; in other words the device of the present invention only requires gravity in order emanate volatile liquid.

According to a second aspect of the present invention there is provided therefore a passive emanation device comprising:

a housing;

a volatile liquid reservoir holding a volatile liquid containing one or more active materials wherein the active material, comprises at least one of; a fragrance; an insecticide; a fungicide; a pesticide; a sanitising material: and/or a pharmaceutical;

one or more capillary tubes In fluid communication with the reservoir at one end thereof wherein said one or more capillary tubes are in non-vaived fluid communication with the reservoir;

a nozzle iocated at the end of the or each capiliary tube(s) remote from the reservoir wherein the o each nozzle is in non-vaived fluid communication with the or each capillary tube(s); and an emanation substrate;

wherein the housing is arranged to support the reservoir, capillary tube and nozzle in spatial arrangement over the emanation substrate. 12397P1

According to a third aspect of the present invention there is provided therefore a delivery mechanism for a passive emanation device according to the first aspect of -tie present invention, wherein the delivery mechanism is cormeciab!e, preferabiy releaseahly correctable, to a housing of the passive emanation device and wherein the delivery mechanism comprises:

a volatile liquid resen/oir holding a volatile liquid containing one or more active materials wherein the active material comprises at least one of: a fragrance; an insecticide; a fungicide; a pesticide; a sanitising material; and/br a pharmaceutical;

one or more capillary tubes in fluid communication with the reservoir at one end thereof wherein said one or more capillary tubes are in non-vaived fluid communication with the reservoir;

a nozzle located at the end of the or each capiiiary tube(s) remote from the reservoir wherein the or each nozzle is in non-valved fluid communication with the or each capillary tube (s).

According to a forth aspect of the present invention there is provided a method of providing a non-valved flow rate of volatile liquid between substantially 0,1 - 50G L hr on to an emanation substrate, wherein the method comprises the steps of placing a device according to the second aspect of the present invention in a location where emanation of I e volatile liquid is desired and causing the norvvaived flow of liquid front the device toward the emanation substrate.

The non-vaived arrangement may provide a device that once the liquid is allowed to flow from the reservoir the liquid will flow substantially continuously from the reservoir into the capillary tube to the nozzle snd:in the form of dropiets on to the emanation substrate at a non-valved flow rate of between substantially 0.1 - SOQt L/hr, and preferably between substantially 20 - 40/ L br, and most preferably between substantially 26 - 34 /L/hr.

With a non-valved passive emanation device, it is critical to provide the device with a flow rate that is suited to ensure a peak emanation delivery rate from the emanation substrate, If th e flow rate is too low the emanation rate will also be low and potentially produce a non-uniform emanation rate from the emanation substrate due to the substrate being generall dry or semi-dry when the liquid contacts the substrate with thus causing the substrate absorb and only slowly release the liquid as well as potentially exposing the components of the liquid to fractionation as the liquid is carried by wicking/capillary action, along the substrate. Conversely if the flow rate is too high the emanation rate may be too high which in the case of a fragraneed liquid could be oveipowering for a user. A high flow rate also the risk of the liquid pooling on the emanatio substrate as the substrate becomes saturated with the liquid, in the case of volatile liquids that can present dangers to the surface on which the device is located since volatile liquids may pose a potential health and/or fire hazard as well as a staining hazard to the surface supporting the device. The present inventors have advantageously found the aforementioned flow rate of 20 - 12397P1

4 ( ¾uL/hr to represent the peak fiow rate to emanate the volatile liquid to ensure satisfactory emanation rate thereof and ensuring the uniform emanation of the liquid whilst substantially preventing any pooling of the liquid on the emanation substrate.

The mass of each droplet is preferably between substantially 0.1 - 500mg, and more preferabl between substantially 0.5 - 7Qrng.

The interrelationship of the various components of the device/delivery mechanism is critical in ensuring that the desired non-vaived flow rate and droplet size is achieved.

The reservoir is preferably substantially completely enclosed to prevent the evaporation of volatile liquid therefrom. The reservoir is preferably provided with a vent hole that can be opened to permit the flow of volatile liquid from the reservoir without the build up of negative pressure or a vacuum in the headspace of the reservoir * The vent hole is preferably provided in a side wail or an upper cover of the reservoir above the max height of the volatile liquid retained therein to permit air to vent into the headspace of the reservoir above the volatile liquid . The vent hole is preferably provided with an area of between substantially 7.9x10"* - LQxlO^mm^ and even more preferably with an area of between substantially 0.8 - 3.1mm 2 . The vent hole is preferably substantially cylindrical and provided with a diameter of between substantially 0,01 - SQmm. and even more preferably with a diameter of between substantially 1 ~ 2mm.

The vent hole ma be covered by a removable sea! member such thai once opened it shall remain open. Alternatively, the vent hole may be covered by a re-sealabie sealing member which can be opened and re-sealed as desired by the user to, in effect, turn the emanation of volatile liquid from the device between a binary on and off position but without providing a user with the ability to select a position therebetween which could alter the non-val ed flow rate.

The reservoir may b sized to retain a volume of volatile liquid between substantially 0.1 - 500ml, and preferably between substantially 10 ~ 40m!.

The reservoir may be shaped such thai the volatile liquid head height therewith In is between substantially 0,1 - 100cm . and preferably between substantially 3 - 10cm; the liquid head height is defined within the context of the present invention as being the height of the liquid from the nozzle to the liquid-air surface in the reservoir. 12397P1

The device/delivery mechanism may be provided with a mechanical boost means which is operable to increase the flow rate of the volatile liquid from the non-valved flow rate to -an enhanced flow rate.

Preferably the mechanical boost means is in the form of ah air pump connected to the reservoir which allows a user to pump air into the headspace of the reservoir to increase the air pressure thereof to at least temporarily increase the flow rate from the non-vaived flow rate to ' the enhanced flow rate, once the user ceases further pumping the non-vaived flow rate will resume once the air pressure in the head space equalises over a period of time.

Alternatively an auxiliary flow route for the volatile liquid may be provided, said auxiliary flow route being operable to being opened by a user to increase the flow rate to the enhanced flow rate before being closed and the flow rate being returned to the non-valved flow rate. The auxiliary flow route may be provided in the form of an aperture in the reservoir, possibly connected to a conduit, wherein the flow of volatile liquid therethrough is controlled by a valve that can be manipulated by a user. The auxiliary flow rout would preferably be provided with a liquid exit orifice located substantially above t e emanation substrate.

The auxiliary flow route may be connected to a auxiliary reservoir of volatile liquid which is adjacent to but not in liquid communication with the reservoir,

The enhanced flow rate may be between substantially 2 - 50 times greater than the non-valved flow rate, and preferabi between substantially 2 - 5 times greater than the non-valved flow rate.

The reservoir may be provided in any shape, however, a substantially cylindrical shape is preferred. For substantially cylindftcally shaped reservoirs they may be provided with a diameter of between substantially 1 - 50cm, but preferably with a diameter of between substantially 4 - 8cm, and may be provided with a depth of between substa tially 0.1 - 100cm, but preferably with a depth of between substantially 0.5 - 2cm.

Preferably at least a portion of the reservoir is transparent to permit a user to see the level of volatile liquid held within , preferably substantially all of the reservoir is transparent.

Preferably the devices/delivery mechanisms according to the present invention are provided with a single capillary connected to the reservoir. The or each capillary tube is preferably made of glass or plastic and may be substantially cylindrical although it could be provided in numerous other geometric shapes. The capillary tube(s) is preferably of a uniform shape and cross-section throughout its length. The capillary iube(s) may be provided with a length of between substantially 0.1 - 50cm, and preferably with a length of between substantially 3 ~ 10cm, In the most preferred embodiment the capillary tufae(s) is/are substantially cylindrical and provided With an internal diameter of between substantially 1 - lOOOjum, and preferably with an internal diameter of between substantially 75 - 1 Q0^m.

The capillary tube(s) may be provided with a filter to ensure that any contaminants in the volatile liquid do not inadvertently cause a blockage to liquid entering and moving along the capillary during use, thus, potentially affecting the flow rate.

The nozzle's) is/are preferably provided with a substantially circular exit orifice having a diameter of between substantially 0.01 - 1 ' OOmm . but preferably has a diameter of between substantially 0.4 - 2mm. The nozzie(s) may be provided with a cap to ensure that no volatile liquid is lost therefrom prior to use by a user.

The volatile liquid for use with the device/delivery mechanism of the present invention preferably possesses the at least one of, or more preferably two of, or most preferably al three of the following properties;

- viscosity between substantially 0.1 - 100cP, and preferably between substantially 1 - 5cP;

- density between substantially 0.1 - 10g/L, and preferably between substantially 0.8 - 1.ig/L;

- average surface tension between substantiall 1 - 100mN/m, and preferably between substantially 1 - 50mN/m.

The effieiency of a particular emanation substrate material depends on the nature of the liquid, or component liquids within the liquid. Most available emanation substrate materials have a limited porosity and liquid transfer rate/evaporation rate due, at least in part, to fractionation and/or blocking/clogging of the material. Fractionation over time will change the character and/or intensity of the active and will slow evaporation, this is particularly noticeable for fragrances wherein common emanation substrate ma terials cause the 'high notes' of a fragrance to be evaporated when the material is first exposed to the fragranced liquid, and the ow notes' are evaporated thereafter which affects the user's experience.

The emanation substrate according to the present invention may e provided in the form of one or more of. cellulose, cardboard (pressed pulp) or fibres; porous plastic; graphite; ceramic; wood 1Z3S7P1

(such as bamboo); reeds (suc as rattan). A particularly preferred emanation substrate material is provided in " the form of balsa wood.

Dried balsa wood has, surprisingly, demonstrated the desired properties of being able to efficientl transfer liquids containing actives, both aqueous and non-aqueous liquids, at a uniform evaporation rate without significant fractionation.

The balsa wood emanation substrate material is dried and may be used in crude form, or it may be first sanded or shaved . Alternatively or additionally said balsa wood emanation substrate material may be shaped by any convenient means to give rods or sheeis of regular cross-section, shaping may be effected by routing, sawing, planing, cutting, lathing or forming in a die. The regular cross-section may by any desired shape, such as circular, elliptical, square, rectangular or polygonal.

As a fu ther alternative the balsa wood emanation substrate .materia! may be molded into a desired shape, said molding may be of the balsa wood before it is first dried or of balsa wood that is initially dried before being wetted to undergo the molding process. Preferably the molding of the balsa wood emanation substrate materia! is to impart a curved shape thereto, whilst the internal mechanics of the resulting structure is not fully understood, it is thought that the curved surface leads to improved emanation of volatile material due a stretching and/or opening of the internal capillaries of the material.

The emanation substrate material of the present invention may be formed into appropriate sizes and shapes suitable for -emanation surfaces having cross-sections with an area of 10mm 2 - 500mm 2 , and preferably 25mm 2 - 400mm 2 , and more preferably 50mm 2 - 300mm 2 , and most preferably 50mm 2 - 250mm '2 .

The emanation substrate material of the present invention may be formed into appropriate sizes and shapes suitable for emanation surfaces having lengths ' -of 1cm - 150cm, and preferably 5cm

- 100cm, and more preferably 0cm - 50cm , and even most preferably 10cm - 25cm.

The emanation substrate material of the present invention may be formed into appropriate sizes and shapes suitable for emanation surfaces having widths of 1 rnm - 500mm. and preferably 2mm

- 200mm t and more preferably 3mm - 100mm, and even most preferably 5mm - 50mm. ίΖ337Ρ1

Preferably where the emanation, substrate material is elongate, such as with rod or sheet shapes and the like, the elongate aspect of the emanation substrate materia! is substantially co-axial with the grain of the material . in a preferred embodiment of the present invention, the emanatio substrate is pre-dosed with the volatile liquid held in the reservoir. To maintain the level of pre-dosing of ihe emanation substrate the emanation substrate ma e covered in a removable pro ective film to prevent er substantially prevent the emanation of the liquid therefrom until the film is removed by a user before use. Alternatively or additionally, the whole device may be sealed in a protective atmosphere ' to reduce or limit any natural evaporation of the pre-dosed volatile liquid from the emanation substrate until a user removes the protective atmosphere immediately prior to use. Such a protective atmosphere may be provided in the form of a sealed packaging or the like. The pre-dosing of the emanation substrate has been found to be particularly advantageous as it ensures that when the non-vaived flow of liquid from: fie reservoir on to the emanation substrate commences, emanation from the substrate is immediately affected whereas without pre-dosing the substrate will, for a initial period of time, mainly absorb the liquid before emanating the liquid into the surrounding environment.

The housing is preferably provided in the form of an open framework which is configured to suspend the reservoir such that the capillary and nozzle are held directly above a substantially centra! point of the emanation substrate. Whilst an open framework is preferred since a user will be able to monitor the progress of volatile liquid from the reservoir t ough the capillary tube and out of the nozzle on to the emanation substrate, ihe framework may be totally o partially enclosed to improve the safe operation of the device by preventing a user from being able to interrupt the flow from the liquid from the nozzle to the emanation substrate.

The preferred volatile liquid used with the device/delivery mechanism/method of the present invention is fragranced liquid for use as an air freshener. The present invention has been found to be particularly advantageous compared with known emanation methods due to the natu e of fragranced volatile liquids.

Brief Description of the . ' Drawings

Embodiments of the invention will now be described, by way of example only, with reference to the following drawings in which:

Fig . 1 illustrates a side sectioned view of an emanation device;

Fig. 2 illustrates a perspective view of ' the emanation device; and

Fig. 3 illustrates a perspective view of a delivery mechanism for a passive emanation device. 123S7P1

Description of an Embodiment

Figs. 1 & 2 illustrate an passive emanation device 1 which is generally arranged to have a housing 2 provided in the form of framework 3 supporting a reservoir 4 which contains a quantity of volatile liquid 5- The reservoir 4 is supported over an emanation substrate 6. The reservoir is provided with a capillary tube 7 which extends from a substantially central portion of the reservoir 4 toward the emanation substrate 6. At the remote end of the capillary tube 7 is located a nozzle 8 from which, in use, volatile liquid will drop towards the emanation substrate 6,

Specifically the device 1 is a passive e nanator as it is not powered by any form of propulsion or motor or electricity etc, rather si simply relies on the force of gravity to be operable and provide a nors-valved flow rate. The device 1 is, importantly, non-valved in that there are no mechanical features of the delivery mechanism which can be altered to Increase or reduce the non-valved flow rate of liquid from the reservoir 4 to the emanation substrate 6 once the liquid has been a!iowed to flow, thus ensuring that the device is operating at an optimum flow rate or not operating at all. The optimum flow rate (the non-valved flow rate) for this device is 0.1 ~ 500/jL/hr, and preferably between substantially 20 - 40 Uhr, and most preferably between substantially 26 - 34jifL/hr. Between 26 - 34>LiL/hr is the optimum flow rate and this is achieved whilst maintaining the mass of each droplet at between substantially 0.1 - 500mg, and but preferably between substantially 0.5 - 70mg. Clearly the inter-relationship of the various components of the device 1 are critical in ensuring that this optimum flow rate and droplet mass is achieved.

As shown in Figs. 1 & 2 the reservoir 4 is substantially completely enclosed which acts to prevent evaporation of volatile liquid 5 therefrom. The reservoir 4 has a vent hole 9 that can be opened to permit the flow of volatile liquid 5 from the reservoir 4 without the biiild up of negative pressure or a vacuum in the head-space of the reservoir. The vent hole 9 is provided in the upper cover of the reservoir. The vent hole 9 is covered by a re-sealabie sealing member 10 which operates via a screw thread mechanism to allow it to be brought into and out of sealing engagement with a upper surface of the vent hole 9.

The reservoir 4 may be sized to retain a volume of volatile liquid between substantially 0.1 - 500ml, but in Figs. 1 & 2 it is sized to retain between substantially 10 - 40ml. The volatile liquid head height therewithin may be between substantially 0,1 - 100cm , but is preferably between substantially 5 - 12cm. The reservoir 4 may be provided in any shape, however, Figs. 1 &2 show the reservoir 4 to be substantially cylindrical with a diameter of■between substantially 4 - 8cm and a depth of between substantially 0.5 - 2cm.

The framework 3 is of an open configuration so thai it does not obscure the reservoir 4 which is transparent, thus permitting a user to see the level of olatile liquid held within. The capillary tube 7 is also transparent which .allows the user to monitor the progress of liquid therethrough on its journey toward the emanation substrate 6.

The capillary tube 7 is shown as being made Of glass and having a substantially uniform cylindrical shape having an internal diameter of between substantially 75 - 10<¾urn and a length between substantially 3 - 10cm. The capillary tube 7 ends at its lowermost portion with the nozzle 8 which is shown as having an exit orifice between substantially 0. - 2mm. The nozzle .is shown as being surrounded by a capillary housing 11 which provides additional safety for the operation of the device but ensuring tha the potentially delicate capillary tube 7 and nozzle 8 can not be accidentally interfered with by a user during normal operation. Furthermore, the capillary housing 1 1 offers the nozzle 8 a degree of shielding from air currents surrounding which may affect the flow rate of volatile liquid droplets leaving the nozzle. Although not shown, the capillary housing 11 and/or the nozzle 8 may be provided with a cap to ensure that no volatile liquid is lost therefrom prior to use by a user.

The emanation substrate 6 could be made from any natural or synthetic material that is at least partially absorbent but is shown here as being made from a natural material which is at least partially absorbent so that it can emanate the volatile liquid over a prolonged period and, also, ensure that the liquid dropped thereon does not remain in drop form resistant to evaporation due to the surface tension thereof.

Fig. 3 shows a delivery mechanism 12 which consists of a reservoir 4 which holds a quantify of volatile liquid 5 covered by a cap of the like (not shown), the reservoir 4 having a capillary tube 7 terminating in a nozzle 8. The delivery mechanism 12 could be used as a refill wherein it is replaceable within the housing 2 once the reservoir 4 held therewithin has been exhausted.

With a hcn-vajved passive emanation system , it is critical to provide the system with a llow rate that is suited to ensure a peak emanation delivery rate from the emanation substrate. To determine the peak emanation delivery rate a series of sensory evaluation tests were conducted using a panel of 16 trained sensory evaluators. A syringe pump rig was placed in an unmarked 28m J sensory booth arranged to dispense a fragranced volatile liquid on to an emanation

\ 1 12397P1 substrate of balsa wood at a defined flow rate. The trained evaluafors were required to assess each booth and accord a sirength of fragrance value on a scale of -1Ό. Samples of Tables 1-3 show the results of different flow rates tested at different times.

Table 1

"Spring Delight " is a fragrance available in liquid form from the AIRWiC ( T ) brand of fragrances.

In addition to the absence of liquid pooling on the emanation substrate, the optimum score for a strength of fragrance value is between 2.75 - 3.50. The results illustrate that flow rates of 2 /L/hr and 34/jL/hr produce a value within the optimum score range, whereas the lower and higher flow rates of 10 L./hr & .SOjuL/h ' r produced values outside of the optimum score range.

Examples are now described which illustrate the interope r tion of the various parameters required to produce a device having the peak flow rates called for in the devices of the preseni invention. ί230ΤΡί

Example 1

Both devices from examples 1 & 2 were operated for a continuous period until the fragranced volatile liquid was exhausted and both devices consistently produced the flow rates and drop weights described above.

All of the features disclosed In this ' specifica tion {including any accompsnying claims, abstract and drawings), and/or ai! of the steps of any method or process so disclosed, may be combined 123S7P1 in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in t is specification (incfuding any accompanying: claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiments ' ); The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accom anying claims, abstract and drawings), or to any novei one, or any novel combination, of the steps of any method or process so disclosed.




 
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