AU2012265591B2 - Chemical formulation supply unit for a vapour emanating device - Google Patents

Abstract

The present invention relates to a device for supplying a chemical formulation to a heater unit 50 for vaporising the formulation into an atmosphere, the heater unit 50 having a body housing an internal heating element, the device comprising: a first portion 12 adapted to be inserted through an aperture 52 in said body of the heater unit 50 such that it is at least partially received within said body of the heater unit 50; a second portion 16 configured to store the chemical formulation and being positionable external to the body of the heater unit 50; and a wick element 14 for delivering said chemical formulation from said second portion 16 to an emanation region 27 provided on said first portion 12; wherein, said first portion 12 is configured to be slidingly received by a variety of heater units 50 having apertures 52 of variable configurations, such that the emanation region 27 is optimally positioned adjacent the heating element for vaporisation of the chemical formulation delivered thereto. Fig. 2

Description

AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT ORIGINAL Name of Applicant: Reckitt Benckiser (Australia) Pty Limited Actual Inventors: Jurg Bartholdi and Daniel Jeremy Craven and Graham Norman Duell and Benjamin David Hindle and Graeme Bruce Smith and Kon Wong Address for Service is: SHELSTON IP 60 Margaret Street Telephone No: (02) 9777 1111 SYDNEY NSW 2000 Facsimile No. (02) 9241 4666 CCN: 3710000352 Attorney Code: SW Invention Title: Chemical formulation supply unit for a vapour emanating device Details of Original Application No. 2006303126 dated 18 Oct 2006 The following statement is a full description of this invention, including the best method of performing it known to me/us: File: 67402AUP01 -2 Chemical Formulation Supply Unit for a Vapour Emanating Device Field of the Invention [0001] The present invention relates to a device for dispensing volatile materials present in formulations, such as insecticides, insect repellents and fragrances, into the atmosphere. In particular, the present invention relates to a device for holding and presenting such materials for dispensing. Background of the Invention [0002] Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field. [0003] A variety of vapour emanating devices are known which function by heating a surface containing volatile material to release the volatile material from the surface into the atmosphere, such that the material can then function as an insecticide, insect repellent and/or an air freshener. [0004] Mat-type vapour emanating devices are widely used for such-purposes. Mat-type devices are generally two part devices consisting of a heater unit which is a relatively non disposable part, and a formulation supply unit that contains the volatile material to be dispensed, which is typically a disposable and/or replaceable part. [0005] The heater unit typically comprises a power plug which is connectable to a power source, such as a common electric power outlet in a household or the like. The power source provides the electrical energy necessary to generate a desired heat in a heating element located within the body of the heater unit. An opening is provided in the body of the heater unit to receive the formulation supply unit such that the formulation can be exposed to the heat generated from the heating element within the heater unit. The opening can assume a variety of shapes and sizes to receive a variety of formulation supply units of various shapes and sizes, generally dictated by the specific manufacturer of the device. [0006] The formulation supply unit typically comprises a planar surface, a portion of which contains the volatile material provided within the formulation. The portion of the surface may comprise an exposed porous region, or mat, which is impregnated with the formulation. Upon -3 insertion of the formulation supply unit through the opening in the body of the heater unit, the porous region, or mat, impregnated with the formulation is positioned generally within the region of the heating elements and is therefore exposed to the high temperatures generated by the heating elements. Exposure of the formulation to sufficient temperatures then causes the volatile material present in the formulation to vaporise into the atmosphere, such that the device can function as an insecticide, insect repellent and/or an air freshener. Upon vaporisation of substantially all of the volatile material present in the formulation supply unit, the formulation supply unit is then removed from the heater unit and discarded. The heater unit is then able to receive replacement formulation supply units and as such the user needs to purchase replacement formulation supply units to use with their existing heater unit. [0007] A common problem with such mat-type devices is that the vaporisation of the volatile material occurs quite rapidly such that the formulation supply units typically last for one night, or period of use, before requiring replacement. Further, there are variations between the thicknesses, size, shape, active ingredient properties and manner in which the mats operate between different manufacturers of the formulation supply units. As such, the heater units provided to receive the various types of formulation supply units typically operate over a wide range of operating temperatures (130-180C). This variation in operating temperatures of the heater units causes a wide variation in the rate of emanation of the volatile material from the various formulation supply units which can be used between differing heater units. This can then result in a formulation supply unit of one manufacture inadequately performing when used with a different type of heater unit. [0008] As the formulation supply units in existing mat-type vapour emanating devices require constant replacement, the user's fingers are often in contact with the porous region, or mat, of the unit during the replacement and disposal process. Such exposure to the formulation and the volatile material is undesirable and can contaminate the user's skin. [0009] In order to avoid the need to regularly replace the formulation supply unit such that the devices operate for more extended periods of time whilst still utilising the existing heater units, variations to the formulation supply units have been proposed. Such variations include providing the formulation in a longer lasting gel mat on the surface of the formulation supply unit, such that the volatile material emanates at a slower rate when inserted into the heater unit. Such devices may operate for a period of up to 30 days before requiring replacement. To accommodate the longer lasting gel mat and to enable the variation to be used in a variety of existing heater units, the formulation supply unit is in the form of a malleable aluminium tray which is adapted to be received by a variety of heater units. However, as the tray is adapted -4 to loosely fit a variety of heater units, the gel mat is not consistently located adjacent the heating elements of the heater unit. Accordingly it has been found that there is a large variation in the heat received by the gel. This causes large variations in the emanation rates of the volatile material between different devices. Therefore, in order to ascertain the remaining life of the formulation supply unit and therefore the amount of gel present thereon, the user must physically remove the formulation supply unit from the heater unit to inspect the gel, which is a cumbersome and inexact exercise. [0010] In this regard, bottle-type vapour emanating devices comprising a clear bottle formulation supply unit containing a large amount of formulation in fluid communication with a wicking device have been proposed, with considerable success. Bottle-type devices provide for extended periods of use, due to their large formulation storage capacity, together with a visual indication of the amount of formulation present in the device so that a user can readily ascertain the operational state of the device. However such devices require the user to purchase a new heater unit to accommodate the bottle formulation supply unit, and cannot utilise the existing heater units available for mat-type devices. [0011] Therefore, there is a need to provide a formulation supply unit for an existing mat type vapour emanating device that can be readily adapted to be received by a variety of existing mat-type heater units and which supplies formulation for extended periods of use and provides a visual indication of the amount of formulation present. [0012] Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is solely for the purpose of providing a context for the present invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed before the priority date of each claim of this application. Summary of the Invention [0013] Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps. [0014] According to one aspect of the present invention, there is provided a device for supplying a chemical formulation to a heater unit for vaporising the formulation into an -5 atmosphere, the heater unit having a body housing an internal heating element, the device comprising: a first portion comprising a substantially planar body having a first surface, an opposed second surface, a proximal end and a distal end, said first portion being adapted to be inserted through an aperture in said body of the heater unit such that it is at least partially received within said body of the heater unit, wherein one or more channels are formed in the first and/or second surfaces of the substantially planar body to facilitate insertion of said first portion into a variety of heater units having apertures of variable configurations; a second portion configured to store the chemical formulation and being positionable external to the body of the heater unit; and a wick element for delivering said chemical formulation from said second portion to an emanation region provided on said first portion; wherein, said first portion is configured to be slidingly received by a variety of heater units having apertures of variable configurations, such that the emanation region is optimally positioned adjacent the heating element for vaporisation of the chemical formulation delivered thereto. [0015] According to another aspect, the present invention is a device for supplying a chemical formulation to a heater unit for vaporising the formulation into an atmosphere, the heater unit having a body housing an internal heating element, the device comprising: a first portion adapted to be inserted through an aperture in said body of the heater unit such that it is at least partially received within said body of the heater unit; a second portion configured to store the chemical formulation and being positionable external to the body of the heater unit; and a wick element for delivering said chemical formulation from said second portion to an emanation region provided on said first portion; wherein, said first portion is configured to be slidingly received by a variety of heater units having apertures of variable configurations, such that the emanation region is optimally positioned adjacent the heating element for vaporisation of the chemical formulation delivered thereto. [0016] In one embodiment, the heating element is a plate and the emanation region of the first portion is positioned at least partially over the plate. In another form, the emanation region may be positioned between the centre of the plate and an edge of the plate, and in yet another form, the emanation region may be positioned approximately 2/3 of the distance from an edge of the plate to the centre of the plate.

-6 [0017] The first portion of the device may comprise a substantially planar body having a first surface and an opposed second surface. In this arrangement, when the first portion is received within the body of the heater unit, the first surface may be that surface which is positioned directly above said heating element. In this regard, the emanation region comprises a recess formed in the second surface. In an embodiment, the wick element comprises an elongate wick member having a first end in fluid communication with said chemical formulation stored in said second portion, and a second end which extends into said recess formed in the second surface of the first portion. The chemical formulation may be vaporised by the heating element from said second end of the wick element, such that the vaporised chemical formulation may be released from said device through said recess. [0018] In another embodiment, the substantially planar body of the first portion of the device has a proximal end and a distal end. The thickness of the substantially planar body may be substantially constant along its length and may taper at its distal end to facilitate insertion of the distal end through the aperture in the body of the heater unit. One or more channels may be formed in the first and/or second surfaces of the substantially planar body to further facilitate insertion of said first portion into a variety of heater units having apertures of variable configurations. Further, one or more guide elements may extend from the first and/or second surfaces of the substantially planar body to contact the body of the heater unit to facilitate optimal positioning of said emanation region adjacent said heating element. The guide elements may be in the form of stepped projections which extend from the first and/or second surfaces of the substantially planar body to contact the aperture formed in the body of the heater unit. One or more stop elements may also project from the first and/or second surfaces of the substantially planar body to contact the body of the heater unit and limit the maximum depth of insertion of said first portion into said heater unit. The one or more stop elements may be provided at the proximal end of the substantially planar body and may be in the form of a wall that at least partially extends across the proximal end of the substantially planar body. [0019] In another embodiment, the second portion of the device may comprise an elongate body defining a substantially tubular space for containing said chemical formulation. In this regard, the body may have a sealed distal end and an opening provided in a proximal end. The first end of the wick member may extend through the opening formed in the proximal end of the elongate body to be in fluid communication with the chemical formulation contained therein. To prevent the wick member from being inserted too deep into the elongate body, a stop member may be provided within said substantially tubular space of said elongate body to abut with said first end of the wick member.

-7 [0020] The elongate body may be relatively flexible such that as the chemical formulation is removed from said elongate body under action of the wick element, it contracts, thereby reducing the size of the substantially tubular containing space in accordance with the volume of chemical formulation removed. Such an arrangement may assist in maintaining a relatively constant pressure within the substantially tubular space and may prevent the generation of a significant vacuum or negative pressure within the space which may be sufficient to possibly adversely affect the ability of the wick to deliver the chemical formulation to the emanation region. [0021] To further facilitate delivery of the chemical formulation from the elongate body, one or more channels may be formed in an inner surface of the elongate body to extend at least partially from the opening provided in the proximal end, to the distal end. Such one or more channels may provide a path for the chemical formulation to flow along said inner surface to the wick element due to capillary action. [0022] In yet another embodiment, the elongate body of the second portion is relatively transparent to provide a user with a visible indication of the amount of chemical formulation present therein. In this regard, the elongate body may be made from a synthetic plastics material, such as nylon or polypropylene, which also provides sufficient flexibility for the elongate body. In one form, the elongate body of the second portion may contain up to 10 mls of chemical formulation. In another form, the elongate body of the second portion may contain up to 2 mls of chemical formulation. [0023] In yet a further embodiment, the first portion may be formed integrally with said second portion. Alternatively, the first portion may be formed separately to said second portion and be fixedly attachable to said second portion. In yet another arrangement, the first portion may be formed separately to said second portion and be removably attachable to said second portion. [0024] The second portion may be thermally isolated from said first portion to minimise the transfer of heat energy from the heater unit to the chemical formulation contained within said second portion. In this regard, the first portion may be made from a material having high thermal resistance and low thermal conductivity. Such a material may be a polyamide or mineral filled nylon or polyphenylene oxide.

-8 [0025] According to another aspect, the invention is a device for supplying a chemical formulation to a heater unit for vaporising the formulation into an atmosphere, the device comprising: a first portion adapted to be received by said heater unit and having an emanation region which is locatable proximal a heating element of the heater unit; a second portion having a container for storing a volume of the chemical formulation; and a wick element for drawing under capillary action said chemical formulation from said second portion and delivering said chemical formulation to said emanation region of said first portion, for vaporisation by said heating element into the atmosphere; wherein, said container defines a substantially enclosed space for storing the chemical formulation and is sufficiently flexible such that as the volume of chemical formulation contained therein reduces, the container contracts thereby reducing the enclosed space available for storing the chemical formulation and minimising the build-up of negative pressure within the container. [0026] According to another aspect, the present invention is a device for supplying a chemical formulation to a heater unit for vaporising the formulation into an atmosphere, the device comprising: a first portion adapted to be received by said heater unit and having an emanation region which is locatable proximal a heating element of the heater unit; a second portion for storing the chemical formulation; and a wick element for drawing said chemical formulation from said second portion and delivering said chemical formulation to said emanation region of said first portion, for vaporisation by said heating element into the atmosphere; wherein, the second portion is thermally isolated from said first portion to minimise the transfer of heat energy from said heater unit to said chemical formulation contained within said container of said second portion. Brief Description of the Drawings [0027] By way of example only, the invention is now described with reference to the accompanying drawings: [0028] Fig. 1 is a top perspective view of a formulation supply unit in accordance with the present invention; -9 [0029] Fig. 2 depicts an exploded view of the unit of Fig. 1; [0030] Fig. 3 depicts a perspective view of a known heater unit suitable for use with the present invention; [0031] Figs. 4A and 4B depict top perspective views und underside views of the locating portion of the unit of Fig. 1; [0032] Fig. 5 depicts a bottom perspective view of the container portion of the unit of Fig. 1; [00331 Fig. 6 depicts a top perspective view of the container portion of Fig. 5; [0034] Fig. 7 depicts a sectional end view of the container portion of Figs. 5 and 6; [0035] Fig. 8 is a top perspective view of the locating portion of the unit with the wick element in position; [0036] Fig. 9 is a perspective view of the manner in which the locating portion and the container portion of the present invention attach; [0037] Fig. 10 is a perspective view of the wick element and gasket in accordance with an embodiment of the present invention; [0038] Fig. 11 is a perspective view of the gasket of Fig. 10 positioned with respect to the container portion; [0039] Fig. 12 is a sectional view of the wick element and gasket in position with respect to the container portion; and [0040] Fig. 13 is a perspective view of the formulation supply unit of the present invention in use with a conventional mat-type heater unit. Detailed Description of an Exemplary Embodiment of the Invention [0041] Referring to Figs. 1 and 2, there is shown a formulation supply unit 10 in accordance with an embodiment of the present invention.

- 10 [0042] As discussed previously, and which will become apparent in the following description, the formulation supply unit 10 is configured to be received within a recess 52 provided in a conventional mat-type heater unit 50, as shown in Fig. 3, which is typically provided for use with a conventional mat-type vapour emanating device. It will be appreciated that the mat-type heater unit 50 as shown in Fig. 3 is merely illustrative of one specific type of a variety of mat-type heater units and the formulation supply unit 10 of the present invention is intended for use with all such varieties. [0043] As is shown, the conventional heater unit 50 includes an electrical plug 54 which enables the unit 50 to be received within a power socket, such as an electrical power socket commonly provided in a home or office environment, to receive electrical power to operate a heating element housed within the heater unit 50. [0044] The heating element for typical mat-type heater units 50 generally employ either a ceramic or a metal plate to distribute heat to the mat portion of the formulation supply unit. A heating resistor is typically located centrally relative to the plate to apply heat energy to the plate. The surface area of the plate can vary, however it generally can be considered to fall with in the range of about 35-45 mm long by about 20-30 mm wide. The ceramic plates are relatively insulating and the temperature gradient measured across the surface of the of the plate can vary considerably. Tests by the present Applicant have indicated that such ceramic plates may have an average temperature measured at its centre of around 1800C and an average temperature measured at its outer edge of around 1150C. With regard to metal plates, such plates are conductive to the heat and have been found to have a more even temperature gradient/profile across its surface. Similar tests by the present Applicant have indicated that such metal plates may have an average temperature measured at its centre of around 150*C and an average temperature measured at its outer edge of around 148*C. [0045] It will be appreciated therefore that for existing mat-type heater units there is a difference in temperature profile between different types of units. As the temperature to which the formulation is exposed controls the emanation rate of the device, such a difference in temperature profiles can greatly affect the emanation rates of the device and as a result the life of the formulation supply unit. Therefore if a mat portion of an existing formulation supply unit is located at the centre of ceramic plate heater unit (1800C) the device would emanate significantly faster than if located over the centre of a metal plate heater unit (1500C), both of which would be much faster than if located at the edge of the ceramic plate heater unit (1150C). Existing mat-type formulation supply units are arranged such that the mat extends substantially wholly over the heater plate when inserted into the heater unit thereby being - 11 subject to a wide variation of temperatures. The present invention takes into consideration this variation in temperature profiles between different existing heater units to provide a relatively even emanation rate when used in both different types of units. [0046] The formulation supply unit 10, generally comprises an elongate body having a two parts: a first locating portion 12 and a second container portion 16. As will be discussed in more detail below, the locating portion 12 is configured to be received within the recess 52 of a conventional heater unit 50 and the container portion 16 is configured to receive and contain a supply of formulation containing the volatile material for emanation in the form of vapour, by the heater unit 50. [0047] As shown more clearly in Fig. 2, a wick element 14 is provided which extends between the locating portion 12 and the container portion 16 to facilitate flow of the formulation present in the container portion 16 to the locating portion 12. The wick element 14 will also be described in more detail below, however is generally in the form of an elongate cylindrical body made of a porous material that allows fluid to flow therethrough under capillary action. A seal member 15 is also provided to ensure a sealed connection between the wick member 14 and the formulation present within the container portion 16. The seal member 15 is in the form of a gasket element through which the wick member is received, and will be described in more detail later in the description. [0048] The formulation supply unit 10 is shown and described in relation to a two part body, namely the locating portion 12 and the container portion 16, which fit together to form a single unit. However, it will be appreciated that both the locating portion 12 and the container portion 16 could be formed integral with one another thereby resulting in a one-piece body. [0049] The locating portion 12 is shown in more detail in relation to Figs. 4A and 4B. The locating portion 12 consists of a substantially planar body 20 having a substantially constant thickness along its length which tapers at a distal end 21. A pair of locating arms 23 extend from a proximal end of the body 20 to facilitate connection of the locating portion 12 to the container portion 16. [0050] Fig. 4A shows a perspective view of what is referred to as the top surface of the locating portion 12. A channel 24 is centrally provided in the top surface of the body 20 and extends along at least a portion of the length of the body. At the distal end of the body 20, the channel 24 spreads out to have a widened neck portion 24a, to assist in inserting the unit 10 into a heater unit 50, and positioning the unit 10 in the desired place. In this regard, the - 12 widened neck portion 24a provides a "lead in" area which enables self-centring of the unit 10 with respect to the heater unit 50 such that a projection (not shown) provided in the body of the heater unit 50 can be readily received in the channel 24 as the unit 10 is inserted into the heater unit 50. As will become more apparent below, this arrangement ensures that the unit 10 is centrally retained within the heater unit 50. To further assist in ensuring that the unit 10 is correctly inserted into the heater unit 50, a pair of cut-out portions 25 are provided in the body 20 in the form of arrows. The arrow shape of the cut-out portions 25 show the direction in which the unit 10 is inserted and may also be provided on the body 20 in the form of adhesive stickers or other indicia which conveys to the user the correct direction of insertion of the unit 10. [0051] A pair of guides 26 are provided on the upper surface of the body 20 as is shown in Fig. 4A. The guides 26 are in the form of stepped projections which extend longitudinally along the upper surface of the body 20 adjacent the proximal end of the body. Each of the guides 26 are provided along the longitudinal edges of the body 20 and aid in locating the unit 10 at an appropriate position within the heater unit 50 and urging the unit 10 against a heating element located with in the heater unit 50. The depth of insertion of the unit 10 into the heater unit 50 is controlled by the presence of the wall 26a located at the proximal end 22 of the unit. In this regard, upon inserting the unit 10 into the heater unit 50, the wall 26a contacts the edge of the recess 52 and prevents the unit 10 from being inserted any deeper into the heater unit 50. [0052] Centrally disposed between the guides 26, adjacent the proximal end 22 of the body 20, is provided an emanation recess 27. The emanation recess 27 is in the form of a substantially rectangular recess formed in the upper surface of the body 20, and has a substantially flat base 29 formed in the lower surface of the body, as is evident in Fig. 4B. A bore 28 extends into the recess 27 through the proximal end 22 of the body 20, such that it is centrally located within the recess 27. [0053] As is shown in Fig. 8, the bore 28 is sized to receive the wick member 14 such that an end of the wick member can extend into the emanation recess 27. In this arrangement, the end of the wick member 14 that extends into the emanation recess 27 is substantially retained within the body 20 and is exposed on the upper surface of the body 20. [0054] Therefore, by inserting the unit 10 into the heater unit 50 such that a projection formed on the recess 52 of the heater unit is received in the channel 24, and inserting the unit to a depth such that the wall 26a contacts the edge of the recess 52, the emanation recess 27, -13 and as a result the end of the wick element 14, is positioned adjacent to the heating elements of the heater unit 50. In this regard, flat base 29 of the emanation recess 27 is positioned to extend over the heating elements of the heater unit 50, allowing heat to transfer through the base 29 to the end of the wick element 14. This alignment and exposure of the end of the wick element 14 to the heating elements of the heater unit 50 is automatic and achieved by merely inserting the unit 10 in accordance with directions and the particular shape of the body 20. [0055] Due to the variation in temperature profiles that exists between different types of existing mat-type heater units 50, as discussed in detail above, the position of the emanation recess 27 with respect to the locating portion 12 has been determined so as to give a relatively even emanation rate when used in different types of heater units. In this regard, the emanation recess 27 is positioned such that when the unit 10 is inserted into the heater unit 50 in the desired manner as discussed above, the exposed end of the wick element 14 is positioned between the edge of the heater plate and the centre of the heater plate. In particular, the end of the wick element 14 is positioned within the unit 10 such that it extends up to about half of the distance to the centre of the plate from the edge of the plate. More preferably, the end of the wick element 14 is positioned such that it is positioned up to about 2/3 of the distance to the centre of the heater plate. In this arrangement, the end of the wick element 14 is located adjacent a region of the heater plate that has a relatively even temperature profile between different types of existing mat-type heater units 50. [0056] Exposure of the end of the wick element 14 to the heat generated by the heating elements/plates of the heater unit 50 enables the volatile material present on the surface of the wick element 14 to be vaporised by the heat applied by the heating elements and released into the atmosphere. [0057] As the heat applied by the heating elements of the heater unit 50 is significantly high, in order to ensure that the body 20 of the locating portion 12 is able to withstand such heat when it is inserted into the heater unit 50, the body 20 is made from a material having high temperature tolerance and low thermal conductivity thereby ensuring that little heat is conducted through the locating portion to the formulation provided in the container portion. [0058] In this regard, the body 20 may be made from a polyphenylene oxide plastic, such as Noryl@ which is able to withstand temperatures in excess of 190"C. Such a material also enables the body 20 to be injection moulded to the desired tolerances to ensure the correct positioning of the emanation recess 27 over the heating elements of the heater element 50. It -14 will be appreciated that other types of heat resistant material may also be used, as would be appreciated by a person skilled in the art. [0059] Whilst the locating portion 12 has been described as having a body 20 specifically configured to be received by recess 52 of a heater unit 50, it will be appreciated that the configuration of the body 20, including the channel 24 and the guides 26 may vary, to conform to a variety of recess shapes and sizes associated with a variety of existing mat-type heater units. In this regard, as in one form the locating portion is detachable from the container portion 16, various locating portions 12 can be produced to be used with a variety of existing mat-type heater units, to be attached to the container portion 16, as necessary. [0060] The container portion 16, is now shown in more detail in relation to Figs. 5 to 7. The container portion 16 comprises a elongate body 30 having a proximal end 31 and a distal end 32. [0061] The proximal end 31 is arranged to engage with the proximal end 22 of the locating portion 12 in the manner as shown in Fig. 9. The proximal end 31 has a pair of receiving passages 33 for receiving the locating arms 23 which extend from the proximal end 31 of the locating portion 12. An opening 34 is provided in the passages 33 into which the barbs 23a of the locating arms 23 are received to secure the arms 23 in position within the locating passages 33 and to provide a secure connection between the locating portion 12 and the container portion 16 as shown. To assist in gripping and securing the locating portion 12 and the container portion 16 together during manufacture, a pair of support wings 35 are provided. [0062] The body 30 of the container portion 16 is crimped, by a heat sealing process or the like, at the distal end 32 to provide a sealed end. As is shown in Fig. 7, the interior of the body 30 defines a space for receiving the formulation to be emanated and the proximal end 31 is provided with a circular opening 36, through which the wick element 14 is received to enter the interior of the body 30. A stop member 37 is provided in the interior of the body 30 upon which the wick member 14 abuts when received through the opening 36, as shown in Fig. 7. The stop member 37 ensures that the length of the wick element 14 inserted into the interior of the body 30 is controlled such that there is a consistent length of the wick element 14 extending into the emanation recess 27 of the locating portion 12. [0063] The wick element 14 transports the formulation present in the body 30 to the emanation recess 27 of the locating portion 12 such that the active ingredients in the formulation can be dispersed into the atmosphere. The wick element 14 extends through the - 15 opening 36 to be in fluid contact with the formulation contained therein. As the formulation is vaporised from the end of the wick element 14 located in the emanation recess 27, formulation present in the body 30 is drawn to the emanation recess 27 under capillary action, until the supply of formulation present in the body 30 is exhausted. [0064] To ensure that fluid present at the distal end 32 of the body 30 is able to be drawn from the body 30 by the wick element 14, one or more channels 38 are formed in the interior walls of the body 30 which extend from the opening 36 at least partially towards the distal end 32. The channels 38 are in fluid contact with the wick element 14 such that fluid can flow, under capillary action, along the channels to the wick element 14 and to the emanation recess 27. [0065] In order to enable a user to readily determine the presence and amount of formulation in the body 30, the body is made from a transparent material, such as nylon, polypropylene and the like which is also relatively flexible. The body is able to store a volume of formulation sufficient to provide at least 100 hours of operation of the device. In this regard, in the event that the device is being used as an insect repellent, this can amount to 10 nights usage of 10 hours per night. As such, the device employing the present invention may be able to achieve an emanation rate of between 0.1-50 mg/hr, preferably between 1-20 mg/hr and more preferably between 3-10 mg/hr. [0066] The container portion 16 is able to store between 0.1-10 mL of formulation, more preferably between 0.3-2 mL of formulation which is sufficient to provide prolonged periods of emanation. Indicia such as arrows or the like may be provided on the external surface of the body 30 to assist the user in orientating the unit 10 for insertion into a heater unit 50. [0067] As discussed previously, the formulation supply unit 10 of the present invention is intended for use in insecticide, insect repellent and/or fragrance dispensing situations. In this regard, the chemical formulation stored within the container portion 16 will vary depending upon the specific situation. [0068] For situations where the formulation supply unit 10 is employed as an insecticide or insect repellent, the chemical formulation may comprise one or more vapour active pyrethroids. It will be appreciated that vapour active pyrethroids are those that are volatile at ambient temperature without heat or combustion. The volatile pyrethroids are preferably selected from the group consisting of metofluthrin transfluthrin, empenthrin, methothrin, tefluthrin, d-allethrin, prallethrin, esbiothrin and fenfluthrin. Preferably, the vapour active - 16 pyrethroid is metofluthrin or transfluthrin. Metofluthrin has high potency against mosquitoes. The chemical name of metofluthrin is 2

,

3 ,5,6-tetrafluro-4-(methoxymethyl)benzyl(EZ) (1 RS,3RS; 1 RS,3SR)-2,2-dimethy-3-(prop-1 -enyl)cyclopropanecarboxylate. Metofluthrin is available from Sumitomo Chemical Company. The chemical name of transfluthrin is [(2,3,5,6 tetrafluoro-phenyl)methyl] 1R, 3

R-(

2

,

2 -dichlorethenyl)-2,2-dimethylcyclopropane-carboxylate. The formulation may also include hydrocarbon solvents (eg Isopars, Exsols etc), dyes, fragrances (maybe) & preservatives. In a preferred form, the chemical formulation may comprise -11% transfluthrin (active), 0.002% Sudan Blue (dye), 0.2% Butylated Hydroxy Toluene (antioxidant), remainder is a mixture of Exsol D110 and Exsol D130 (hydrocarbons). [0069] For situations where the formulation supply unit 10 is employed in a fragrance dispensing device, the chemical formulation may include natural or synthetically derived aroma chemicals. These chemicals include substances that preferably have a boiling point range of about 60-250*C (e.g. monoterpenes and sesquiterpenes, including monoterpene and sesquiterpene alcohols, aldehydes, ketones, esters, oxides and hydrocarbons such as linalool, geraniol, citronellal, citral, geranial, menthone, linalyl acetate, bornyl acetate, 1,8-cineole and limonene); and essential oils. The term "essential oils" refers to a volatile and aromatic liquid which is isolated by a physical process from an odoriferous plant of a single botanical species. The oil bears the name of the plant from which it is derived; for example rose oil or lavender oil. These essential oils obtained from plants may be extracted by distillation, steam distillation, expression or by extraction with fats or organic solvents. (0070] In each of the above situations, the active component of the chemical formulation may be dissolved in a carrier solvent. The carrier solvent may be any solvent or combination of solvents in which the vapour active pyrethroid is soluble. The carrier solvent may be selected from, but not limited to, chlorinated hydrocarbons (e.g. 1,1,1-trichloroethane, dichloromethane, chloroform); alcohols (e.g. methanol, ethanol, n-propanol); ketones (e.g. acetone); alcohol and ketone mixtures (e.g. acetone/ethanol (1:1 by volume)); normal paraffins (e.g. Norpar@ 12); dearomatised aliphatic hydrocarbons and their blends (e.g. pentane, heptane, hexane, Exxsol D40, Exxsol D80 and Exxsol D100); isoparaffins (e.g. Isopar@ G, and Isopar@ M); glycol ethers; natural or synthetically derived aroma chemicals as discussed above. The Norpar@, Exxsol@ and Isopar@ solvents are all available from Mobil Exxon. [0071] One common problem with bottle-type vapour emanating devices of the prior art, is that as the formulation is drawn from the bottle portion of the device through the wicking or capillary action of the wick element, a negative pressure, or vacuum, is created within the bottle. This is typically due to the rigid nature of the bottle portion which stores the formulation.

-17 The presence of such a negative pressure, or vacuum, generates an opposing force that counteracts the flow of liquid from the bottle portion, which can significantly slow, and in some instances completely stop, the rate of emanation of the device by reducing the capillary effect of the wicking element. In the present arrangement, as the body 30 has a degree of flexibility and is sealed at one end, as the formulation is drawn from the body under capillary action, the body 30 collapses as it empties. This collapsing of the body 30 reduces the volume of the body as the formulation empties thereby maintaining a relative constant pressure within the body 30. Hence, the creation of a vacuum within the body 30 is minimised ensuring that the formulation can be drawn from the body at a relatively constant rate to maintain a constant rate of emanation of the device. [0072] The wick element 14 is made from a high density ceramic material having a high capillary action. In a preferred form the wick element 14 is cylindrical and has a diameter of approximately 2.0 mm and a length of 16 mm. To provide a liquid tight seal around the wick element 14 and between the locating portion 12 and the containing portion 16, a seal member 15 is provided as is shown in Figs. 10 to 12. [0073] The seal member 15 is in the form of a gasket 40 having an inner ring portion 42 and an outer ring portion 43 connected by flanges 44. The inner ring portion 42 has central bore 41 which forms a first sealing surface around the wick element 14 as shown in Fig. 10. The rear and front surfaces of the inner ring portion 42 for second and third sealing surfaces between the container portion 16 and the locating portion 12 respectively. [0074] As shown more clearly in Fig. 11, the proximal end 31 of the body 30 of the container member 16 has a ridge 45 formed about the opening 36 for receiving and retaining the gasket 40 in position. In this regard, the outer surface of the outer ring portion 43 substantially conforms to the inner surface of the ridge 45, securing the gasket 40 in position. The flanges 44 which connect the inner ring portion 42 and the outer ring portion 43 act to retain the portions together as well as providing room for the gasket 40 to expand during use and temperature fluctuations. [0075] The outer ring portion 43 acts to provide structural robustness and integrity to the unit 10 when in the assembled form as shown in Fig. 1. In this regard, any bending moment acting on the wick element 14 is transferred to the outer ring portion 43 which acts against the ridge 45. This flexible portion can minimise the direct bending moments transferred to the wick element 14 thereby reducing the likelihood of damage to and breakage of the wick element 14 during use of the unit 10.

-18 [0076] The gasket 40 is preferably made from a rubber material, such as nitrile butadiene rubber (NBR) or hydrogenated nitrile butadiene rubber (HNBR). [0077] During use, the unit 10 is provided in the manner substantially as shown in Fig. 1. A label (not shown) is provided which extends over the emanation recess 27 prior to usage of the unit 10, and seals emanation recess 27, thereby protecting the user form potential contamination with the formulation before use. In this regard, the label is in the form of an adhesive that adheres to the upper surface of the locating portion 12 and is readily peelable from the surface to initiate use and insertion of the unit 10. In another embodiment, the label may be heat sealable peelable label. [0078] Upon removal of the label, the unit 10 is then inserted through the recess 52 into the heater unit 50 whereby the locating portion 12 is substantially received within the heater unit 50 whilst the container portion 16 is located externally with respect to the heater unit 50, as shown in Fig. 13. [0079] As discussed above, due to the manner in which the surface of the locating portion 12 is configured, the unit 10 is automatically positioned such that the emanation recess 27 into which the end of the wick element extends, is positioned accurately and consistently over the desired region of the heating elements of the heater unit. The heat generated by the heating elements is sufficiently high and of a consistent temperature to then cause vaporisation of the formulation present on the wick element 14, releasing the volatile ingredients into the atmosphere at the desired rate to perform their desired function. [0080] Whilst the locating portion 12 is subject to the high temperatures present in the heater unit 50, which can amount to around 1800C, the container portion 16, and in particular the formulation contained therein, is retained at near ambient temperature. This is achieved through the locating portion 12 being made from a heat resistant material having very low heat conductivity, such that the volatile ingredients present in the formulation are not subject to temperatures that can cause them to become released from the formulation prior to being drawn to the end of the wick element 14. Further, as the container portion 16 is located externally to the heater unit 50 as shown in Fig. 13, it is not subject to a confined heat space which may result in the formulation being exposed to undesirable temperatures. [0081] The formulation supply unit 10 as shown, provides a safe and convenient means for supplying formulation to a heater unit that provides an indication to the user of the state of the unit and the amount of formulation present therein, without requiring visual inspection and - 19 potential contact of the user with the formulation as is the case with existing mat units. The unit 10 is able to be inserted into an existing heater unit in a variety of orientations, each controlled to automatically present the end of the wick element 14 to the heating elements of the heater unit, for emanation therefrom. [0082] It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims (30)

1. A device for supplying a chemical formulation to a heater unit for vaporising the formulation into an atmosphere, the heater unit having a body housing an internal heating element, the device comprising: a first portion comprising a substantially planar body having a first surface, an opposed second surface, a proximal end and a distal end, said first portion being adapted to be inserted through an aperture in said body of the heater unit such that it is at least partially received within said body of the heater unit, wherein one or more channels are formed in the first and/or second surfaces of the substantially planar body to facilitate insertion of said first portion into a variety of heater units having apertures of variable configurations; a second portion configured to store the chemical formulation and being positionable external to the body of the heater unit; and a wick element for delivering said chemical formulation from said second portion to an emanation region provided on said first portion; wherein, said first portion is configured to be slidingly received by a variety of heater units having apertures of variable configurations, such that the emanation region is optimally positioned adjacent the heating element for vaporisation of the chemical formulation delivered thereto.

2. A device according to claim 1, wherein the heating element is a plate and said emanation region of the first portion is positioned at least partially over said plate.

3. A device according to claim 2, wherein the emanation region is positioned between the centre of the plate and an edge of the plate.

4. A device according to claim 3, wherein the emanation region is positioned approximately 2/3 of the distance from an edge of the plate to the centre of the plate.

5. A device according to any one of the preceding claims, wherein said first surface is positionable to face said heating element.

6. A device according to any one of the preceding claims, wherein said emanation region comprises a recess formed in said second surface.

7. A device according to claim 6, wherein said wick element comprises an elongate wick member having a first end in fluid communication with said chemical formulation stored in said - 21 second portion, and a second end which extends into said recess formed in the second surface of the first portion.

8. A device according to claim 7, wherein said chemical formulation is vaporised by said heating element from said second end of the wick element, such that the vaporised chemical formulation is released from said device through said recess.

9. A device according to any one of the preceding claims, wherein the substantially planar body has a substantially constant thickness which tapers at its distal end to facilitate insertion of said distal end through said aperture in said body of the heater unit.

10. A device according to any one of the preceding claims, wherein one or more guide elements extend from the first and/or second surfaces of the substantially planar body and are configured to contact the body of the heater unit to facilitate optimal positioning of said emanation region adjacent said heating element.

11. A device according to claim 10, wherein said guide elements are stepped projections which extend from the first and/or second surfaces of the substantially planar body to contact the aperture formed in the body of the heater unit.

12. A device according to claim 10 or claim 11, wherein one or more stop elements project from the first and/or second surfaces of the substantially planar body to contact the body of the heater unit and limit the maximum depth of insertion of said first portion into said heater unit.

13. A device according to claim 12, wherein the one or more stop elements are provided at the proximal end of the substantially planar body.

14. A device according to claim 13, wherein the one or more stop elements comprise a wall that at least partially extends across the proximal end of the substantially planar body.

15. A device according to any one of the preceding claims, wherein the second portion comprises an elongate body defining a substantially tubular space for containing said chemical formulation, said body having a sealed distal end and an opening provided in a proximal end. - 22

16. A device according to claim 15, wherein the first end of said wick member extends through said opening formed in the proximal end of the elongate body to be in fluid communication with the chemical formulation contained therein.

17. A device according to claim 16, wherein a stop member is provided within said substantially tubular space of said elongate body to abut with said first end of the wick member.

18. A device according to claim 15, wherein the elongate body is relatively flexible such that as the chemical formulation is removed from said elongate body under action of the wick element, the elongate body contracts thereby reducing the size of the substantially tubular containing space in accordance with the volume of chemical formulation removed, to maintain a relatively constant pressure within the substantially tubular space.

19. A device according to any one of claims 15 to 18, wherein one or more channels are formed in an inner surface of the elongate body and extend at least partially from said opening provided in the proximal end to the distal end, said one or more channels providing a path for said chemical formulation to flow along said inner surface to said wick element.

20. A device according to any one of the preceding claims, wherein said body is relatively transparent and provides a user with a visible indication of the amount of chemical formulation present therein.

21. A device according to claim 20, wherein the body is made from a synthetic plastics material.

22. A device according to claim 21, wherein the synthetic plastics material is nylon or polypropylene.

23. A device according to claim 1, wherein the second portion contains up to 10 mls of chemical formulation.

24. A device according to claim 23, wherein the second portion contains up to 2 mls of chemical formulation.

25. A device according to any one of the preceding claims, wherein the first portion is formed integrally with said second portion. - 23

26. A device according to any one of claims 1 to 24, wherein the first portion is formed separately to said second portion and is fixedly attachable to said second portion.

27. A device according to any one of claims 1 to 24, wherein the first portion is formed separately to said second portion and is removably attachable to said second portion.

28. A device according to any one of the preceding claims, wherein the second portion is thermally isolated from said first portion to minimise the transfer of heat energy from said heater unit to said chemical formulation contained within said second portion.

29. A device according to claim 28, wherein the first portion is made from a material having high thermal resistance and low thermal conductivity.

30. A device for supplying a chemical formulation to a heater unit for vaporising the formulation into an atmosphere substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying drawings and/or examples.