AU2007308747A1

AU2007308747A1 - Protective sheath

Info

Publication number: AU2007308747A1
Application number: AU2007308747A
Authority: AU
Inventors: Michael Charles Cooke
Original assignee: BRANDO INTERNAT Ltd
Current assignee: BRANDO INTERNATIONAL Ltd
Priority date: 2006-10-24
Filing date: 2007-10-24
Publication date: 2008-05-02
Also published as: EP2079349A1; WO2008049162A1

Description

WO 2008/049162 PCT/AU2007/001620 PROTECTIVE SHEATH FIELD OF THE INVENTION The present invention relates to food processing apparatus and particularly to apparatus immersible in a contaminating liquid. 5 The invention has been developed primarily as a protective sheath for a steam wand of a coffee making machine. However, it will be appreciated that the invention is not limited to this particular field of use. BACKGROUND OF THE INVENTION Any discussion of the prior art throughout the specification should in no way 10 be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field. Coffee making machines typically provide a steam wand for frothing milk to make hot milk-based beverages, such as cafe lattes, hot chocolates and mochacinos. Conventionally, the steam wand is dipped into a container of milk, and hot steam 15 and/or water vapour is discharged from the wand to create a milky froth that is subsequently transferred to the beverage. This results in the steam wand being covered by some of the frothed milk, which if left uncleaned forms a scum-like residue that is unsightly, difficult to remove, unhygienic and encourages the growth of bacteria. Therefore, the steam wand must be cleaned, ideally after each use. 20 However, the wand is usually cleaned manually with a wet rag, which may have been used to clean other surfaces. Thus, contaminants contained in the rag, such as dirt and bacteria, may be transferred onto the steam wand. This creates a hygiene and food safety hazard, In addition, when the milk is heated it is desirable that the temperature of the 25 milk is below 65', otherwise it will "scald" and can lead to a bitter or undesirable aftertaste in the hot milk-based beverage. Typically, stainless steel thermometers have been used to indicate the temperature of the milk to avoid overheating of the milk past its "scalding" temperature. However, it has been found that it is difficult to clean such stainless steel thermometers, and thus there has been a tendency not to use WO 2008/049162 PCT/AU2007/001620 -2 those thermometers and instead guess when the milk is approaching its scalding temperature. This obviously results in an increased risk of adversely affecting the taste of the milk-based beverage. OBJECT OF THE INVENTION 5 It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative. It is an object of the present invention in at least one preferred form to provide a protective sheath for a steam wand of a coffee making machine that inhibits contamination of the steam wand, is easily cleanable and is removable. Lo It is an object of the present invention in at least one preferred form to provide a protective sheath for a steam wand of a coffee making machine that inhibits contamination of the steam wand while indicating the temperature of the milk. SUMMARY OF THE INVENTION One aspect of the present invention provides a protective tubular sheath for a is lance immersible in a, contaminating liquid, said lance having a discharge nozzle at its distal end, said sheath comprising: a neck opening at one end adapted for releasable attachment to said lance adjacent said nozzle and further having a discharge opening at its other end, said sheath being protectively evertable over said lance such that said discharge 20 opening moves over said neck opening to protectively cover an immersible portion of said lance. Another aspect of the present invention provides method of protecting a lance imiersible in a contaminating liquid, said lance having a discharge nozzle at its distal end, said method comprising the steps of; 25 providing a tubular sheath having a neck opening at one end and a discharge opening at its other end; WO 2008/049162 PCT/AU2007/001620 -3 releasably attaching said neck opening to said lance adjacent said nozzle, and everting said sheath over said lance such that said discharge opening moves over said neck opening to protectively cover an immersible portion of 5 said lance. Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "comprising, but not limited to". 10 Preferably, said sheath is. evertable such that the previously inner surface of said sheath is exposed to said contaminating liquid during use. Preferably, the sheath is re-evertable for cleaning said inner surface by fluid discharge from said nozzle and through said discharge opening. Preferably, the neck opening comprises a resilient member for attaching the 15 sheath to the lance. Preferably, the resilient member forms a substantially fluid tight seal with the nozzle. Preferably, the resilient member is in the form of a sleeve. Preferably, the resilient member comprises one or more rings for gripping the lance or nozzle. Preferably, the resilient member comprises one or more fingers for gripping the underside of the nozzle without substantially obstructing fluid discharge 20 therefrom. Preferably, the resilient member comprises a mesh or netting for gripping the underside of the nozzle without substantially obstructing fluid discharge therefrom. Preferably, the discharge opening lies in a plane at an oblique angle to the longitudinal axis of the sheath. Preferably, the sheath has a frusto-conical body. 25 Alternatively, the sheath may substantially conform to the shape of the lance. In this alternative embodiment, the sheath is made of a flexibly resilient material such that the sheath contracts around or grips the lance as it is everted.

WO 2008/049162 PCT/AU2007/001620 -4 Preferably, the sheath is made of a flexibly resilient material. Preferably, the sheath is heat resistant and/or corrosion resistant. Preferably, the sheath comprises an anti-bacterial material. Preferably, the sheath is transparent or translucent. Preferably, the sheath has one or more of these properties, as required. That is, the 5 sheath may be formed with one or more properties selected from the group consisting of heat resistance, corrosion resistance, moisture resistance, anti-bacterial, transparency and translucence. Preferably, the discharge opening comprises a compression member for facilitating eversion and re-eversion of the sheath. Preferably, the compression 10 member is at least partially annular. Preferably, the discharge opening comprises a handle for operating the sheath, Preferably, the handle extends radially outward relative to the lance. Preferably, the discharge opening comprises a lip. Preferably, the lip comprises a hand engaging portion, 15 Preferably, the sheath comprises one or more markings. Preferably, the markings indicate predetermined levels for immersing the lance in the contaminating liquid. Preferably, the sheath is at least partially made of a thermochromic material for indicating one or more predetermined temperatures of the contaminating liquid. 20 Preferably, one or more zones of the sheath comprise thermochromic pigments. Preferably, the zones of the sheath comprise substantially parallel strips along the length of the sheath. Preferably, said everting step comprises exposing the previously inner surface of said sheath to said contaminating liquid during use. Preferably, the everting step 25 is performed such that the sheath engages or grips the lance as it is everted. Preferably, the method comprises the step of re-everting the sheath. Preferably, the re-everting step is performed such that the sheath engages or grips the lance as it is re-everted.

WO 2008/049162 PCT/AU2007/001620 -5 Preferably, the method comprises the step of cleaning the inner surface. Preferably, the cleaning step is performed after the re-everting step. Preferably, the cleaning step comprising discharging fluid from said nozzle and through said discharge opening. 5 Preferably, the attaching step comprises forming a substantially fluid tight seal between the neck opening and the nozzle. Preferably, the sheath providing step comprises forming the sheath with one or more properties selected from the group consisting of heat resistance, corrosion resistance, moisture resistance, anti-bacterial, transparency and translucence. 10 Preferably, the method comprises the step of indicating predetermined levels on the sheath for immersing the lance in the contaminating liquid. Preferably, the method comprises the step of at least partially forming the sheath with a thernochromic material for indicating one or more predetermined temperatures of the contaminating liquid on the sheath. 15 Preferably, the contaminating liquid is a beverage, comprising milk. Preferably, the lance is a steam wand, Preferably, the nozzle is an aspirating nozzle. BRIEF DESCRIPTION OF THE DRAWINGS Preferred embodiments of the invention will now be described, by way of 20 example only, with reference to the accompanying drawings in which: Figure 1 is a perspective view of a protective sheath according to one embodiment the invention prior to attachment to a steam wand of a coffee making machine; Figure 2 is a perspective view illustrating the protective sheath of Figure 1 25 attached to the steam wand; WO 2008/049162 PCT/AU2007/001620 -6 Figure 3 is a perspective view illustrating the protective sheath of Figure 1 being everted; Figure 4 is a perspective view illustrating the protective sheath fully everted on the wand; 5 Figure 5 is a perspective view illustrating the protective sheath in use; Figure 6 is' a perspective view illustrating the protective sheath re-everted; Figure 7 is a perspective view of a protective sheath according to another embodiment of the invention attached to a steam wand of a coffee making machine; Figure 8 is a perspective view illustrating the protective sheath fully everted on 10 the wand; Figure 9 is a perspective view of a protective sheath according to a further embodiment of the invention attached to a steam wand of a coffee making machine; Figure 10 is a side view illustrating the protective sheath of Figure 9 in an installed position attached to the steam wand; 15 Figure 11 is a perspective view illustrating the protective sheath of Figure 9 in use; Figure 12 is a side view of the protective sheath of Figure 9 in use; Figure 13 is a front view of the protective sheath of Figure 9 in use; Figure 14 is a top view of the protective sheath of Figure 9 in use; 20 Figure 15 is a partial cut-away cross-sectional view of the neck opening of'the protective sheath of Figure 9 in use; Figures 16 to 19 are cut-away cross-sectional views of the protective sheath of Figure 9 in use; WO 2008/049162 PCT/AU2007/001620 -7 Figure 20 is a cross-sectional view of the sheath of Figure 9 in use, with a stirrup for attaching the sheath to the wand; Figure 21 is a cross-sectional view of the sheath of Figure 9 in use, with a mesh cage for attaching the sheath to the wand; 5 Figures 22A to 22C are cross-sectional views of an adaptor ring for attaching the sheath of Figure 9 to different types of wands and nozzles; and Figure 23 is a perspective view of the sheath according to a further embodiment of the invention in a collapsed form in its packaging for storage and transport. 10 PREFERRED EMBODIMENTS OF THE INVENTION The drawings illustrate a protective tubular sheath I applicable to a lance 2 immersible in a contaminating liquid 3. The lance is in the form of a steam wand 2 of a coffee making machine (not shown) and has an aspirating discharge nozzle 4 at its distal end 5. The sheath I has a neck opening 6 at one end 7 adapted for 15 releasable attachment to the wand 2 adjacent the nozzle 4, and further has a discharge opening 8 at its other end 9. As best shown in Figures 3 and 4, the sheath 1 is protectively evertable over the wand 2 such that the discharge opening 8 moves over the neck opening 6 to protectively cover an immersible portion 10 of the wand 2. This exposes the 20 previously inner surface 11 of the sheath 1 to the contaminating liquid 3 during use. Figure 4 illustrates the protective sheath 1 in its operative position, protectively covering the innersible portion 10 of the wand 2. The neck opening 6 comprises a resilient sleeve 12, which is either bonded to or formed integrally with the transparent frusto-conical body of the sheath 1. The 25 resilient sleeve 12 forms a substantially fluid tight seal between the nozzle 4 and the neck opening 6, thus inhibiting or preventing the egress of any froth or liquid into contaminating contact with the wand 2. The discharge opening 8 lies in a plane 13 WO 2008/049162 PCT/AU2007/001620 that is at an oblique angle to a longitudinal axis 14 of the sheath 1. The discharge opening 8 also comprises a lip 15, from which depends a hand engaging portion 16. The sheath comprises a circumferential marking 17 on its outer surface, which indicates a predetermined optimum level for immersing the wand 2 in the 5 contaminating liquid when the sheath 1 is everted. To this end, the sheath I is substantially transparent to enable the marking 17 to be visible when the sheath I is everted to expose the inner surface 11. Alternatively, the marking 17 can be provided on the inner surface 11 so that it only becomes visible when the sheath I is eveted into its operative position as shown in Figure 4. 1.0 In this embodiment, the invention also provides a method of protecting a lance 2 immersible in a contaminating liquid 3, the lance 2 having a discharge nozzle 4 at its distal end 5. The method comprises the steps of providing a tubular sheath I having a neck opening 6 at one end 7 and a discharge opening 8 at its other end 9, and releasably attaching the neck opening 6 to the lance 2 adjacent said nozzle 4. Is The method further comprises everting the sheath 1 over the lance 2 such that the discharge opening 3 moves over the neck opening 6 to protectively cover an immersible portion 10 of the lance 2. The steps of the method and operation of the sheath according to this embodiment of the invention is described in more detail below. 20 To install the sheath 1, it is attached to the wand 2 by inserting the nozzle 4 into the neck opening 6 so that resilient sleeve 12 engages and grips the nozzle 4, forming a substantially fluid tight seal between the nozzle 4 and the neck opening 6, as best shown in Figure 2. From this installed position, the hand engaging portion 16 is used to lift the discharge opening 8 over the neck opening 6 and nozzle 4, everting 25 the sheath I so as to expose the previously inner surface 11 of the sheath 1, as best shown in Figure 3. That is, the sheath 1 is turned inside out as the discharge opening 8 is lifted over the neck opening 6. Once the sheath 1 is fully everted into its operative position, as shown in Figure 4, the sheath I now protectively covers the immersible portion 10 of the wand 2 to shield this immersible portion from any WO 2008/049162 PCT/AU2007/001620 -9 potential contaminants which may adhere to its surface when the wand 2 is being used to make a beverage, such as to froth milk. To use the wand 2, for example to froth milk for a cafe latte, the wand with the protective sheath I is dipped into a container 18 of nilk 3 up to the line defined by 5 circumferential marking 17, as best shown in Figure 5. The wand 2 is then actuated to froth the milk 3 in the usual way. Since the protective sheath 1 surrounds the now immersed portion 10 of the wand 2, it prevents any froth from adhering to the surface of the wand 2 during its operation. After completing the milk frothing operation, the container 18 is removed and 10 the frothed milk poured over the cafe latte, Any milk or froth residue that remains adheres only to the exposed, previously inner surface 11 of the everted sheath 1, leaving the wand 2 free from any potential contaminants. To remove or clean the sheath 1, it is re-everted from its operative position of Figure 4 into its installed position, as shown in Figure 2. If the sheath 1 is to be 15 disposed, it is simply removed by pulling the sheath 1 to detach the resilient sleeve 12 from the nozzle 4. However, if the sheath 1 is to be cleaned for reuse, the wand 2 is simply actuated to discharge hot water, water vapour or steam 19 and flush the inner surface 11 of the sheath 1, as best shown in Figure 6. Any froth or liquid milk residue is removed by the hot water or steam 19 through the discharge opening 8 into 20 an empty container 20. The re-evertwd sheath also protects the user from the hot steam during the cleaning process. The protective sheath 1 is preferably made of a flexibly resilient material which is heat-resistant to sustain repeated use. The sheath may comprise a coat of anti bacterial material to further inhibit the growth of bacteria in proximity to the wand 2. 25 In addition, the sheath 1 is sufficiently stiff to support itself. Alternatively, the lip 15 or hand engaging portion 16 can be tied to the coffee making machine using a hook, catch, latch or other attachment means.

WO 2008/049162 PCT/AU2007/001620 - 10 Another embodiment of the invention is illustrated in Figures 7 and 8, where corresponding features have been given the same reference numerals. In this embodiment, the sheath I is formed from a flexibly resilient material such that the sheath contracts around or grips the lance 2 as it is everted. Thus, the sheath 1 can be 5 everted and re-everted by moving the sheath up and down the wand 2, respectively, so as to substantially conform to the shape of the wand 2. This also allows the sheath 1 to be self-supporting; that is, the sheath I is able to hold itself in the operative position without the assistance of any other attachment mechanism, such as hooks, catches and latches. This embodiment minimises the amount of milk displaced and 0 maximises the throughput of the steam into the milk and the visibility of the frothing process. The neck opening 6 has also replaced the resilient sleeve 12 with an integrally formed circumferential ring 21 that is able to stretch over the nozzle 4 and form a fluid tight seal with the 'wand 2. Furtbennore, the discharge opening 8 comprises an is enlarged handle 22 that extends radially outwardly to enable the sheath I to be used with one hand and thus minimises the risk of the barista coming into contact with the heated wand 2, thus enabling the sheath to be everted and re-everted safely. This embodiment operates in a similar fashion to the embodiment described in Figures 1 to 6. To install the sheath 1, the ring 21 is stretched over the wand 2 so 20 that it grips the wand just above the nozzle 4, thus forming a substantially fluid tight seal between the nozzle 4 and the neck opening 6, as best shown in Figure 7. From this installed position, the handle 22 is used to lift the discharge opening 8 over the neck opening 6 and nozzle 4, everting the sheath 1 so as to expose the previously inner surface 11 of the sheath, as best shown in Figure 8. That is, the sheath 1 is 25 turned inside out as the discharge opening 8 is lifted over the neck opening 6. Once the sheath 1 is fully everted into its operative position, as shown 'in Figure 8, the sheath I now protectively covers the immersible portion 10 of the wand 2 to shield this immersible portion from any potential contaminants which may adhere to its surface when the wand 2 is being used to make a beverage, such as to froth milk.

WO 2008/049162 PCT/AU2007/001620 - i1 To use the sheath covered wand 2, for example to froth milk for a cafe latte, it is dipped into a container of milk, and the wand 2 is actuated to froth the milk in the usual way. Since the protective sheath 1 surrounds the now immersed portion 10 of the wand 2, it prevents any froth from adhering to the surface of the wand 2 during 5 its operation. After completion of the milk frothing operation, any milk or froth residue that remains adheres only to the exposed, previously inner surface 11 of the everted sheath 1, leaving the wand 2 free from any potential contaminants. The sheath I is then either removed or cleaned, as described in relation to the embodiment of Figures 1 to 6. That is, the sheath 1 is re-everted from its operative 10. position in Figure 8 into its installed position of Figure 7, where it can be detached for disposal or cleaned for reuse by actuating the wand 2 to discharge hot water, water vapour or steam 19 and flush the inner surface 11 of the sheath 1. In the latter case, the discharge opening 8 contracts to create a cigar-like tube farming a pressurised chamber, thus ensuring an elevated temperature within the volume 15 enclosed by the re-everted sheath. This effectively sterilises the sheath for repeated use. A further embodiment of the invention is illustrated in Figures 9 to 19, where corresponding features have been given the same reference numerals. This embodiment is similar to the embodiment of Figures 7 and 8 in that the sheath 1 is 20 made of silicone to contract around or grip the wand 2 as it is everted so as to substantially conform to the shape of the wand. The sheath 1 has a discharge opening 8 arranged to flare radially outwards in the everted position, as best shown in Figures I1 to 14 and 16 to 19. A relatively rigid compression ring 23 is formed at the discharge opening 8 to facilitate repeated 25 everting and re-everting. Due to the equilateral elastic forces in the attached sheath 1, the compression ring 23 effectively hovers clear of the wand 2. The compression ring 23 comprises a highly visible handle 24 to assist in use of the sheath I with one hand. The arrangement of the flared discharge opening 8, compression ring 23 and handle 24 ensures that the user does not come into contact with the heated wand 2 30 during the everting.and re-everting operation.

WO 2008/049162 PCT/AU2007/001620 - 12 The sheath 1 also has a second relatively rigid circumferential ring 25 below the ring 21. Together the rings 21 and 25 permit retrofitting of the sheath 1 to a wide variety of steam wands in commercial use. The rings 21 and 25 also securely attach the sheath 1 to the wand 2, as well as ensuring a fluid tight seal with the nozzle 4. 5 The ring 25 also helps to hold the neck opening 6 down during the everting operation so that the sheath is not everted above the nozzle 4, compromising the fluid tight seal. Where there are steam ports in the nozzle 4 above the line of the second ring 25, the ports can still discharge steam past the ring 25 during a steaming operation, and afterwards, the ring 25 seals against the underside of the nozzle 4 to inhibit the 10 ingress of milk and contaminated water. The subsequent steam cleaning of the sheath also sterilises this area of the nozzle. The handle 24 also includes written material for indicating the type of contaminating liquid that the sheath in being immersed. For example, in a coffee making machine iWith several wands 2, one wand may be dedicated to soy milk, 15 whereas another wand is dedicated to milk, and the written matter on handle 24 provides a convenient means of reference. Alternatively, the handles 24 can be colour coded to indicate the type of contaminating liquid. The colour-coding could also be used to indicate how long the sheath has been in use; for example, red coloured handles indicate a day shift, yellow coloured handles for the afternoon shift 20 and blue coloured handles for the night shift. This permits the sheaths to be replaced regularly to improve hygiene. Written advertising matter can be marked on the handle, including the product name of the sheath "Wandom" 26. In addition, this embodiment is at least partially formed with tbermochromic material to indicate a predetermined temperature of the milk, This feature 25 advantageously prevents overheating of the milk. Typically, the temperature of the milk should be monitored to prevent it from overheating, otherwise the milk will "scald" (usually at 65") and add a bitter or undesirable aftertaste to the milk-based beverage, especially coffee. Conventionally, stainless steel thermometers are used to determine when the milk approaches its scalding temperature so that the barista will 30 know when to stop frothing the milk. However, it has been found that it is difficult WO 2008/049162 PCT/AU2007/001620 - 13 to clean such stainless steel thermometers, and thus there has been a tendency for baristas to guess when the milk is ready before it reaches the scalding temperature. In the embodiment, the entire sheath comprises thermochromic material so that the sheath changes colour to indicate the temperature of the milk. The 5 thermochromic material takes the form of thermochromic pigments that change colour at a temperature just below the scalding temperature of 65*, and then changes colour again once the milk temperature reaches or exceeds 65". The thermochromic pigments then change colour when the temperature drops to ambient temperature. Alternatively, the thermochromic material may permanently change colour once the 10 scalding temperature is reached. It will be appreciated that the thermochromic material can be formed with the sheath 1 in several ways. For example, in another embodiment, the sheath has one or more zones or areas of thermochromic material. Alternatively, the thermochromic material is embedded into the sheuth. In one preferred embodiment, the sheath 15 comprises an area or zone having thermochromic pigments in the form of parallel strips running along the length of the sheath. It will be appreciated that the thermochromic zones can be formed in any manner as desired, such as letters, symbols, shapes, logos, numbers, or even the predetermined level markings on the sheath. Thus, the sheath may provide a useful indicator to a barista as to when to 20 stop frothing the milk and thus avoid contamination by exceeding the scalding temperature. This embodiment operates in a similar fashion to the embodiment described in Figures 7 and 8. To install the sheath 1, the ring 21 is stretched over the wand 2 so that it grips the wand just above the nozzle 4 and the ring 25 grips the end of the 25 nozzle 4, as best shown in Figures 10 and 15. Thus, the sheath I conforms to the shape of the nozzle, thus forming a substantially fluid tight seal between the nozzle 4 and the neck opening 6. From this installed position, the handle 24 is grasped to lift the compression ring 23 and discharge opening 8 over the neck opening 6 and nozzle 4, everting the sheath I so as to expose the previously inner surface 11 of the sheath. 30 Thus, the sheath I is turned inside out as the discharge opening 8 is lifted over the WO 2008/049162 PCT/AU2007/001620 -14 neck opening 6. During the everting operation, the compression ring 23 ensures that the handle 24 is spaced from the wand 2 as it moves parallel to the axis of the wand. Once the sheath 1 is fully everted into its operative position, the sheath 1 now protectively covers the immersible portion 10 of the wand 2 to shield this immersible 5 portion from any potential contaminants which may adhere to its surface when the wand 2 is being used to make a beverage, such as to froth milk. To use the sheath covered wand 2, for example to froth milk for a cafe latte, it is dipped into a container of milk, and the wand 2 is actuated to froth the milk in the usual way. Since the protective sheath 1 surrounds the now immersed portion 10 of 10 the wand 2, it prevents any froth from adhering to the surface of the wand 2 during its operation. Once the milk temperature is close to the scalding temperature, the thermochromic pigments in the sheath react and change colour, indicating to the user that the frothing of the milk should cease. If frothing continues and the scalding temperature is reached, the sheath changes colour again to indicate that the frothed 15 milk cannot be used and should be replaced with a new batch of milk. After completion of the milk frothing operation, any milk or froth residue that remains adheres only to the exposed, previously inner surface 11 of the everted sheath 1, leaving the wand 2 free from any potential contaminants. The sheath 1 is then either removed or cleaned by re-everting it from its 20 operative position into its installed position. The sheath 1 is re-everted along the same parallel axis, assisted by the compression ring 23, to ensure that the user's hand is protected from the heated wand 2. From its installed position, the sheath 1 is detached for disposal or cleaned for reuse by actuating the wand 2 to discharge hot water, water vapour or steam 19 and flush the inner surface I I of the sheath 1. 25 Again, the discharge opening 8 contracts to ensure an elevated temperature within the volume enclosed by the re-everted sheath, thus effectively sterilising the sheath for subsequent use. Thus, the preferred embodiments provide a semi-reusable protective sheath I that prevents the accumulation of milk residue on the steam wand 2, reducing any 30 labour involved in removing the residue and preventing contamination of the wand 2.

WO 2008/049162 PCT/AU2007/001620 - 15 Furthermore, the sheath 1 avoids the need for manual cleaning of the wand 2, thus preventing the transfer of contaminants such as dirt and harmful bacteria from a cleaning rag. In addition, the sheath I can be cleaned hygienically using hot water or steam 19 from the nozzle 4. Alternatively, the sheath 1 can be replaced after each 5 use. Preferred flexibly resilient materials for the embodiments of the invention comprise plastic, rubber, silicone and other elastic materials. Naturally, the sheath is also composed of material that is biochemcially inert to comply with food safety requirements. 10 In a further embodiment of the invention, the sheath 1 can be everted and re everted by -rolling the sheath up and down the wand 2, respectively, so as to substantially conform to the shape of the wand 2. In other embodiments, the sheath 1 is generally cylindrical rather than frusto conical in shape. The sheath may also reverse its orientation so that the sheath tapers 15 inwardly from the neck opening to the discharge opening, provided that it is evertable over the lance in the manner described. Other configurations for the sheath body are also contemplated. In another embodiment, the sheath may use a flexible handle ring as an alternative to the compression ring of Figures 9 to 19. The flexible handle ring also 20 facilitates version of the sheath, and has a greater diameter than the majority of the sheath when in the everted position Furthermore, the flexible handle ring could comprise a loop to hook up with the top of the sheath, where the sheath is not made of an elastic material to conform to the shape of the wand. In a further embodiment, the compression ring 23 can be replaced with a 25 partially annular shape, such as a hook-shape, horseshoe-shape or V-shape, so long as it enables the expansion, eversion and manipulation of the discharge opening 8. In yet another embodiment, multiple compression rings 23 are provided along the length of the sheath to improve its rigidity in the everted position. The compression WO 2008/049162 PCT/AU2007/001620 -16 ring 23 and its variants can also be formed as part of the packaging or packaging support to minimise the materials used in the sheath. A further embodiment provides a handle on the sheath for manipulating the wand itself, either via the handles 22 and 24 or an entirely separate handle 5 attachment. This obviates the need for the user to use the grommet that is usually installed on the coffee making machine when the sheath is installed, The sheath can also be provided with suitable attachments for retrofitting the sheath to a wide array of steam wands that are found in use, Aside for the double ring arrangement of Figures 9 to 19, one form of attachment comprises replacing the 10 lower second ring 25 with one or more "stirrups", which are elastically connected to the upper ring 21. A further variation involves elastically connecting one or more stirrups to the lower second ring, which in this case would be less rigid than its counterpart in the double ring arrangement. As best shown in Figure 20, the ring 21 is placed just above the nozzle 4 and the elastically draws the stirrup 27 into 15 engagement with the underside of the nozzle. The stirrup 27 allows any steam ports above to discharge steam unhindered or unobstructed by the sheath 1. As best shown in Figure 21, another form of attachment comprises a stainless steel mesh cage 28 attached to the upper ring 21 to fit around the nozzle 4 and its underside, again permitting the steam ports above to discharge steam unhindered or unobstructed by 20 the sheath. As shown in Figures 22A to 22C, a further embodiment employs an adaptor ring 29 that enables the sheath to be fitted to different types of wands and nozzles. Referring to Figure 22A, the adaptor ring 29 is fitted to the wand 2 above the nozzle 4 like a washer, over which the sheath I is attached so as to secure it to the wand. 25 In a further embodiment, the sheath is collapsible or articulated so that it can be folded into a compact body for case of storage and minimising the volume of the packaged sheath and the amount of material required for packaging the sheath, as best shown in Figure 23. The packaging 30 comprises a heat seated pack 31 containing the collapsed sheath 1, and pre-formed peel apart tabs 32 to ensure that 30 the sheath can be removed without contamination, Collapse of the sheath may be WO 2008/049162 PCT/AU2007/001620 - 17 achieved by pre-forming concertina or origami-like folds in the sheath, or the use of multiple rings acting as fold lines. It will be appreciated that the sheath may be used for other applications where a lance needs to be protected from a contaminating liquid. Accordingly, the sheath 5 can be formed to have additional or alternative anti-contamination properties, if required. Such properties could comprise corrosion resistance or moisture resistance. Furthermore, it will be appreciated that these anti-contamination properties for the sheatb can be individually selected or combined, according to the desired properties. Although the invention has been described with reference to specific examples, 10 it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.

Claims

1. A protective sheath for a lance immersible in a contaminating liquid, said lance having a discharge nozzle at its distal end, said sheath comprising: a neck opening at one end adapted for releasable attachment to said lance adjacent 5 said nozzle and further having a discharge opening at its other end, said sheath being protectively evertable over said lance such that said discharge opening moves over said neck opening to protectively cover an immersible portion of said lance.

2. The sheath of claim 1, wherein said sheath is evertable such that the previously inner surface of said sheath is exposed to said contaminating liquid during use. 10

3. The sheath of claim 1 or 2, wherein sheath is re-evertable for cleaning said inner surface by fluid discharge from said nozzle and through said discharge opening.

4. The sheath of any one of the preceding claims, wherein the neck opening comprises a resilient member for attaching the sheath to the lance.

5. The sheath of claim 4, wherein the resilient member forms a substantially fluid 15 tight seal with the nozzle.

6. The sheath of claim 4 or 5, wherein the resilient member is in the form of a sleeve.

7. The sheath of claim 4 or 5, wherein the resilient member comprises one or more rings for gripping the lance or nozzle.

8. The sheath of any one of claims 4 to 7, wherein the resilient mmber comprises 20 one or more fingers for gripping the underside of the nozzle without substantially obstructig fluid discharge therefrom.

9. The sheath of any one of claims 4 to 7, wherein the resilient member comprises a mesh or netting for gripping the underside of the nozzle without substantially obstructing fluid discharge therefrom. 25

10. The sheath of any one of the preceding claims, wherein the sheath substantially conforms to the shape of the lance. WO 2008/049162 PCT/AU2007/001620 - 19 It.

The sheath of claim 10,- wherein the sheath is made of a flexibly resilient material such that the sheath contracts around or grips the lance as it is everted,

12. The sheath of any one of claims 1 to 9, wherein the discharge opening lies in a plane at an oblique angle to the longitudinal axis of the sheath. 5

13. The sheath of any one of the preceding claims, wherein the sheath is formed with one or more properties selected from the group consisting of heat resistance, corrosion resistance, moisture resistance, anti-bacterial, transparency and translucence.

14. The sheath of any one of the preceding claims, wherein the discharge opening flares outwardly in the everted position. 10

15. The sheath of any one of the preceding claims, wherein the discharge opening comprises a compression member for facilitating version and re-eversion of the sheath.

16. The sheath of claim 15, wherein the compression member is at least partially annular.

17. The sheath of any one of the preceding claims, wherein the discharge opening IS comprises a handle for operating the sheath,

18. The sheath of claim 17, wherein the handle extends radially outward relative to the lance.

19. The sheath of any one of the preceding claims, wherein the sheath comprises one or more markings for indicating predetermined levels for immersing the lance in the 20 contaminating liquid.

20. The sheath of any one of the preceding claims, wherein the sheath is at least partially made of a thermochromic material for indicating one or more predetermined temperatures of the contaminating liquid.

21. The sheath of claim 20, wherein one or more zones of the sheath comprise 25 thermochromic pigments. WO 2008/049162 PCT/AU2007/001620 - 20

22. The sheath of claim 20 or 21, wherein said zones of the sheath comprise one or more strips at least partially along the length of the sheath.

23. The sheath of any one of the preceding claims, further comprising an adaptor ring for attaching the sheath to different types of lances and nozzles. 5

24. The sheath of any one of the preceding claims, wherein the contaminating liquid is a beverage, comprising milk.

25. The sheath of any one of the preceding claims, wherein the lance is a steam wand and the nozzle is an aspirating nozzle.

26. A method of protecting a lance immersible in a contaminating liquid, said lance 10 having a discharge nozzle at its distal end, said method comprising the steps of: providing a tubular sheath having a neck opening at one end and a discharge opening at its other end; releasably attaching said neck opening to said lance adjacent said nozzle, and everting said sheath over said lance such that said discharge opening moves over 1.5 said neck opening to protectively cover an immersible portion of said lance.

*27. The method of claim 26, wherein said everting step comprises exposing the previously inner surface of said sheath to said contaminating liquid during use.

28. The method of claim 26 or 27, the everting step is performed such that the sheath contracts around or grips the lance as it is everted. 20

29. The method of any one of claims 26 to 28, wherein the method comprises the step of re-everting the sheath.

30. The method of any one of claims 26 to 29, wherein the method comprises the step of cleaning the inner surface.

31. The method of claim 30, wherein the cleaning step is performed after the re 25 everting step. WO 2008/049162 PCT/AU2007/001620 -21

32. The method of claim 30 or 31, wherein the cleaning step comprises discharging fluid from said nozzle and through said discharge opening.

33. The method of any one of claims 26 to 32, wherein the attaching step comprises forming a substantially fluid tight seal between the neck opening and the nozzle. 5

34. The method of any one of claims 26 to 33, wherein the sheath providing step comprises forming the sheath with one or more properties selected from the group consisting of heat resistance, corrosion resistance, moisture resistance, anti-bacterial, transparency and translucence.

35. The method of any one of claims 26 to 34, wherein the method comprises the step 10 of indicating predetermined levels on the sheath for immersing the lance in the contaminating liquid.

36. The method of any one of the claims 26 to 35, wherein the method comprises the step of at least partially forming the sheath with a thernochromic material for indicating one or more predetermined temperatures of the contaminating liquid on the sheath. 15

37. The method of any one of claims 26 to 36, wherein the contaminating liquid is a beverage, comprising milk.

38. The method of any one claims 26 to 37, wherein the lance is a steam wand and the nozzle is an aspirating nozzle.

39. A protective sheath for a lance immersible in a contaminating liquid, 20 substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying drawings and/or examples.

40. A method of protecting a lance immersible in a contaminating liquid, substantially as herein described with reference to any one of the embodiments of the invention 25 illustrated in the accompanying drawings and/or examples.