GB2481427A - Emanation device comprising one or more capillary tubes - Google Patents

Abstract

An emanation device 1 emanates a volatile liquid 5 containing one or more active materials, wherein the active material comprises at least one of: a fragrance, insecticide, fungicide, pesticide, sanitising material and/or a pharmaceutical. The emanation device comprises: a housing 2, a passive delivery mechanism (12, Fig. 3) and a powered emanation means 6, wherein the housing is arranged to support the passive delivery mechanism in spatial arrangement over the emanation means. The passive delivery mechanism comprises a volatile liquid reservoir 4, one or more capillary tubes 7 in non-valved fluid communication with the reservoir at-one end thereof and a nozzle 8 located at the end of each capillary tube(s) remote from the reservoir, wherein each nozzle is in non-valved fluid communication with each capillary tube(s). Preferably, the emanation means is a heater or an ultrasonic transducer. A method of providing a flow rate of volatile liquid between 0.1-500 mL/hr onto the emanation means is also claimed.

Description

VolatUe Liciuid Eniango.p Device

Field of the lnve ion

The present invention relates to a volatile liquid delivery mechanism for an emanation device wherein said volatile liquids comprise actIve components such as fragrances, insecticides, nu igicices pestimdes sanitizing ma tenals ai d pharmaceuticals are pro' ided and pm twularly tie present inventIon relates to a passive, non-powered volatile liquid delivery mechanism for a powered emanation device. mourd

Convenhunal passwe emanatn-'n devices foi volatile liquids typically voi k by exposing a one sd of a permeable membrane to a reservoir of the volatile liquid, in such membrane-containing emanation devices, the membrane is in constant contact on one side thereof with the liquid and exposed to U-ic external environment on its other side. The contact between lhe 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 simpleto construct they contain several drawbacks, some r.

of which are icentified betow. r

One drawback, particularly with the emanation of air fresheners is that of a phenomenon called 0 Thabituation". 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 it 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 fraorance or not.

A further drawback associated with devices having a membrane in constant ccntact with a volatile matenal such ac a olatue liquid an freshenci rs 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 thu housnq caused by tne emanation of the volaiilc mate ial I nis build up phur oniena can cause unacceptable performance problems with such a device from a consunier perspective.

in the field of air freshening it is generally preferred to use a volatile liquid fragrance/air freshener comprising several components. These components often possess different volatil ities 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 occurleading to an undesirable non-uniform emanation profile for the liquid.

In either or both cases of build-up phenomena and accumulation of low volatility components, the evaporatron rate. and thus the emanEtson rate, of the volatile liquid adopts the profile shown iii Fia 4.

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

A further drawback with known passive volafile liquid en-ianators is that prolonged exposure of the \olatile liquid to a wrking matenal such as a membrane or the like can cause fiaconaton ovei time oue to vmous factors such as the wicking matenal haiing a limited porosit affecting linuid tansfei Jates/evaporation rates which n turn cau chansu the haracler and/or intensity ot the volatile liquid being emanated. Changes in character ol 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 fragranced liquid: and the low nntes rhO evapuiated thereafter shich difects the usai s experience r r Turning to drawbacks with known powered emanation devices, the effect of frectionafion is particularly pronounced for powered emanation devices using a heater to effect emanatton, such 0 as a plugin emanation devico or tne like The phenomenon doecubed abo e herein rhanges c\i in chaiacter for fragranues are noticeahlL as the high notes of a fraqrance are the fiistto be evaporated when the wicking material is first exposed to the fragranced liquid, and the low notes' are evaporated thereafter which affects the user's experience is found to be particularly pronounced when a heater is used to drive the emanation of the fragrance.

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.

qmrnarv of lnventiQfl According to a first aspect of the present invention there is provided therefore an 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 emanation device comprises: a housing; a passive delivery mechanism; a powered emanation means; wherein the housing is arranged to support the passive deiivery mechanism in spatial arrangement over the emanation means; and wherein the delivery mechanism comprises: a votatile iquicl 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-valved fluid communication with the reservoir; and a nozzle oca ted at the end of the o each capibary tubes) remote trom the resorvor whmen the or each nozzle is in non-valved fluid communication sUth the or each capillary tubets).

In the context of the present invention "non-valved" 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 thereth rough.

In the context of the present invention "passive" should he understood as rheaning that that the r delivery mechansm is operable witnout a power source or some other means which dnves the uelrerv of the vola tie rend to the emanation means in other nrds the delrvcry machanisro of th present mvention only requires gravi: in order de1rver olatrle liquid to tne emanabon means c\i According to a second aspect of the present invention there is provided therefore an emanation device comprising: a housing; a passive delivery mechanism: a powered emanation means; wherein the housing is arranged to support the passive delivery mechanism in spatial arrangement over the emanation means; and wherein the deiivery mechanism comprises: a volatile liquid reservoir holding a volatile liquid containing one or more a ctive materials wherein the active material comprises at least one of: a fragrance; an insecticide: a fungicide; a pesticide; a sanitising material; andior a phannaceu tical; one or more capillary tubes in fluid communication with the reservoir atone end thereof whenain sad ono or more rapdarv tubes ne in non valved fluid rommunca Rn sith the resevr and a nO7Zls locatcd at the end ci the or eacn capillary tubers remore rom the r'sseoi whrrern ho or each nozzle is in non-valved fluid communication with the or each capitlanj tube(s).

According to a third aspect of the present invention there i5 provided therefore a passive dehvery mechanism for an emanation device according to the first aspect of the present invention, wherein the delivery mechanism is connectable, preferably releaseably connectable, to a housing of the emanation device and wherein the passive delivery mechanism comprises: a volatile liquid reservoir holding a volatile liquid containing one or more active materials wherein the active material comprises at ieast 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 comniunicaon 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'nal flow rate of volatile liquid between substantially 0.1 -500pL/hron to an emanation means, 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 the volatile liquid is desired and causing the normal flow of liquid from the passive delivery mechanism toward the emanation means and r activating said emanation means to emanate the volatile liquid into the surrounding environment. r

The non-valved arrangement may provide a delivery mechanism that once the liquid is allowed to 0 flow from the reservoir the liquid will flow substantially continuously from the reservoir into the capillary tube(s) to the nozzle(s) and on to the emanation means at a normal flow rate of between substantially 0.1 -500pL/hr, and preferably between substantially 1 -5OpLJhr. This normal flow rate has, surprisingly, been found to represent the optimal rate to emanate the volatile liquid to ensure satisfactory emanation thereof whilst rninimising the onset of habituation to the volatile liquid. The mass of each droplet is preferably between substantially 0.1 -500mg. and more preferaty between substantially 0 5 -70mg.

The inter-relationship of the various components of the delivery mechanism is critical in ensuring that the desired normal flow rate and droplet size is achieved, The reservoir is preferabiy 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 neqative. pressure or a vacuuni in the headspace of the reservoir. The vent hole is preferably provided in a side wall 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 wfth an area of between substantially 7Sxi03 -. I,9x1 03mm2, and even more preferably with an area of between substantially 0.8 -3imm, The vent hole is preferably substantially cylindrical and provided with a diameter of between substantially 0.01 50mm, and even more preferably with a diameter of between substanhally 1 -2mm.

The vent hole may be covered by a removable seal member such that, once opened it shall remain open. Alternatively, the vent hole may be covered by a re-sealable sealing member which can he 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 hut without providing a user with the ability to select a position therebetween which could alter the normal flow rate.

The reservoir may be sized to retain a volume of volatile liquid between substantially 0.1 500m1.

and preferably between substantially 10 -40m1.

The reservoir may be shaped such that the volatile liquid head height therewithin is between substantially 0.1-100cm, and preferably between substantially 3-lOom; the liquid head height is defined within the context of the present invention as being the height of the liquid from the r nozzle to the hquid-air surface in the reservoir. r

The device and/or delivery mechanism may be provided with a meohanioal boost means which is 0 operable to increase the flow rate of the volatile liquid from the normal flow rate to an enhanced C'J flow nate, Preferably the mechanical boost means is in the form of an 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 teniporarily increase the flow rate from *the normal flow rate to the enhanced flow rate, once the user ceases further pumping the normal 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 beüig closed and the flow rate being returned to the normal 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 route would preferably be provided with a liquid exit orifice located substantially above the emanation substrate.

The auxiliary how route may be connected to a auxfiiary reservoir of volatile Uquid which is adjacent to bt not in liquid rommunication waii the iosarvoir The enhanced flow rate may be between substantially 2 -50 times greater than the normal flow rate, and preferably between substantially 2 5 times greater than the normal flow rate.

The reservoir may be provided in any shape, however, a substantially cylindrical shape is preferred. For substantially cylindrically shaped reservoirs they may be provided with a diameter uf between substantially I -50cm L ut preferably with i hamctci ol between substan'jally 4 8cm, and may be provided with a depth of between substantially 0.1 -100cm, but preferably with a depth of between substantially 0.5 2cm.

Preferably atleasta portion of the reservoir is transparent to permit a user o see the evel 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. r r

The or each capillary tube is preferably made ol glass or plastic and may be substantially cylindrical although it could be provided in numerous other geometric shapes. The capillary 0 tube(s) is preferably of a uniform shape and cross-section throughout its length. The capillary tube(s) may be provided with a length of between subslanlially 0.1 -50cm, and preferably with a length of between substantially 3-10cm. In the most preferred embodiment the capillary tube(s) is/are substantially cylindrical and provided with an internal diameter of between substantially I - 1000pm. and preferably with an internal diameter of between substantially 75-100pm.

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/arepreferably provided with a substantially circular exit orifice having a diameter of between substantially 0.01 -100mm, but preferably has a diameter of between substuntially 0.4 -2mm. The. nozzle(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 a least o e of or mnre pre'erabl two of or most preferably al ibreu ot the fotiowing properties: \ iccsit'1 hetwL.en substantially 0 -iGOoP and prmer'3My beweLn substant'ah1 1 -cP -density between substantially 0.1 lOg/L, and preferably between substantially 0.8 1.ig/L: avecige suifae tensirn between suhstint ally 1 -lOOinN/m and preferabk hebeen substantially I -5Gm N/rn.

The emanation means is preferably provided in the form of a heater thermally connected to a heater plate which is operable to increase its temperature to accelerate the evaporation of the volatile liquid from the heater plate. Alternatively the heater plate could he provided in the form of an ahani bent matenal such as a wick material which is capable of transportinq the tolatile liqiid toward the heater to volatise the liquid from the absorbent material.

Altematively, the emanation means is provided in the form of a ultrasonic transducer element, such as a piezo-actuated emenator wherein the volatile liquid drops directly on to the piezo emanator or on to a plate connected to said piezo-actuated emanator arid volatised therefrom once the emanator is activated.

r The emanation means may be powered by mans supplied electricity and/or be battery powered and/or be powered by solar cells located on the device, preferably the emanation means are battenj powered however to afford greater portability over a device wherein the emanation means 0 use mains-supplied electricity. Alternatively the device may be provided with a docking station which may be batten, powered and/or mains electricity powered n order to provide a charge to batteries held within the device to power the emanation means such that the device may be removed from the docking station for improved portability.

The housing is preferably provided in the form of an open framewori< which is configured to suspend the reservoir such that the capillary and nozzle are held directly above a substantially central point of the emanation rneau Wnnst an open framework is pieferred since a user will ue able to monitor the progress of volatile tiquid from the reservoir through the capillary tube and out of the nozzle on to the emanation means, the framework may be totally or partially enclosed to improve the safe operation of the device by preventing a user from being able to interrupt the flovv from the liquid from the nozzie to the emanation means.

The preferred volatile liquid used with the deviceklelivery 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 natuna of fragranced volatile liquids.

DescrigjionfJjeDjis Embuoinints of the invertion wili now be Jescnbed by way rf e'ampto iily wth rcferooce to the following drawings in which: Fig. I 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.

Qgs"ipon of an Embodiment Figs. 1 & 2 illustrate an emanation device I which is generaUy arranged to have a housing 2 provided in the form of framework 3 supporting a delivery mechanism 12 which contains a quantity of volatile liquid 5. The delivery mechanism 12 is supported over an emanation means 6.

The delivery mechanism 12 has a reservoir 4 which is provided in this embodiment with a single capillary tube 7 which extends from a substantially central portion of the reservoir 4 toward the emanation means 6. At the remote end of the capillary tube 7 is located a nozzleS from which, in use, volatile liquid wilt drop towards the emanation means 6.

r Speciflcally the delivery mechanism 12 is a passive nibchanism as it is not powered by any form r of propulsion or motor or electricity etc. rather it simply relies on the foroe of gravity to be operable end provide a normal flow rate. The delivery mechanism 12 is, importanUy, nonvaived 0 in that there are no mechanical features of the delivery mechanism which can he altered to c\i reduce the normal flow rate of liquid from the reservoir 4 to the emanation means 6 once the (\J liquid has been allowed to flow, thus ensuring that the device is operating atan optimum flow rate or not operaUng at all. The optimum flow rate (the normal flow rate) for this device is 0.1 -SDOpLIhr, butpreferabty the rate is between substantially I -SOpLihr. This optimum flow rate is, ideally, 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-r&ationship of the v'wous ccmpouent of the delvery mecnanism 12 u cntical in ensunnq that this optimum flow rate and droplet mass is achieved.

As shown in Figs. I & 2 the reservoir 4 is substantially completely enclosed which acts to prevent evaporation of volatfle liquid Stherefromn. The reservoir4has a vent hole 9 that can be opened to permit the flow of volatile liquid 5 from the reservoir 4 without the build up of negative pressure or a vacuum in the headspace 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-sealable 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 500m1, hut in Figs. I & 2 it is sized tn retain between substantially 10 -40m1, The volatile liquid head height therewithin may be between substantially 0.1 -100cm, but is shown as being between substantially 5-12cm.

The reservoir 4 may be provided in any shape, however. Figs. I &2 show the reservoir 4 to be substantially cylindrical witha diameter of between substantially 4 -8cm and a depth of between substantially 0.5 -2cm.

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

The capillary tube 7 is shown as being made of glass and having a substantially uniforn'i cylindn,al shape having an internal diameter of between substantially 75 -100pm an a lengtn r r 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 0.4-2mm. The nozzle is shown as being currounded by a capillary housing 11 which provides adoitional safety for tho 0 opeiaton of the deiue but onsunnq that the potenually delicate rapillary tube 7 and nozzle 8 can not be accidentally interfered with by a user during normal operation. Furthermore, the capillary housing 11 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 Ii andJor the nozzle 8 maybe provided with a cap to ensure that no volatile tiquid is lost ft ererrom piior 10 use ova usr The emanation means 6 is provided in the form of an ultrasonic transducer powered by a piezo-actuator. The transducer is pow ered by batteries (not shown) and iS operable to actuate at routine intervals in order to cause the break up of the volatile liquid drops dropped thereon into small paruclec haang enough kinetc ene,q to travel into the suiwundinq environeinent Fig. 3 shows the dehvery mechanism 12 which consists of a reservoir 4 which holds a quantity of volatile liquid 5 covered by a cap of the like (not shown), the reservoir 4 having a capillary tube 7 temiinating in a nozzie 8, The delivery mechanism 12 could be used as a refill wherein it is replaceable within the housing 2 once the reservoir 4 held therewith in has been exhausted.

EmpIes are now described which iUustrate the interoperation of the various parameters required to pioduLe a deIun1 mechanism having the optimum flov iates cafled for n he devi-es of the present invention.

Example I

CapfflaryLengi 46 mm __________ nnerCapfflsry_Diameter 100um __________ Nozzle Diameter 1 4 mm Drop weight ________ 115mg Reservoir Volume 30 mL (fragrance) ___________ ___________________ Liquid Head Height (from Sb 6 mm nozzle tip to top of JquifQ ________ _____ Reservoir D!amete 6cm ______________ Reservoir Depth 1.06 cm Vent Hole Diameter ________ 1 mm _______________ aranceViscosit'_3.2 oP____ Fragrance Density 0.89g/L ftance &a-facc Tension 26 8 mN/m v" flow Rate 29.7 uL/hr r 0 Exampe2 Capillary Length ________ ___________ timer Capillary Diameter 100 tim ________________ Nozzle Diameter _________ 6.9 mm ______________ PtqRs11.t_______ __________ Reservoir \/olume 30 i-n L (fragrance) _______ ____ ____________ Liquid Hearl Hcight (Sum 1106mm noLzie tip tompofjq_ ____ -_____________ Reservoir Diameter _______ $ cm _________ Reservoir Depth 1.06 cm ffragranceY __________ _____ ______________ Vent Hole Diameter 1 mm pranreVsLosity 32cP _____________ 0.89 giL Fra3rante Si rfar'e Tension 26 8 mN'm -FlowRate _________ 26.7 uL/hr _____ Both devu es from examples 1 & 2 wcie operated for a con inuuus period until the fragranced oLtile liowc was Lmaubtd end tne rleHve& mcLhinism of both devices cons tenty produced the flow rates and drop weights described above. It)

AU of the features disclosed in this specification (including any accompanying claims, abstract and drawings) and or -ll of the stepc or ant mothoi cii piocess so oislosd may be conibucd in any rornbmahon exept comhnatjons where at least some of such features and/or steos are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may he replaced by ci ternative features serc4ng the same, equivalent or similar purpnse unless epressl sterJ otherwise Thus unless expressly stated oth,L vise each feature disclcced is oie c <ample only cit a qenenr sene of equivalent ci irnuar features The invenhon is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanythg claims, abstract and drawings), or any novel one, or any novel combination, of the steps of any meThod or process so disclosed. r r c'J (4 Ii