WO2003092865A1

WO2003092865A1 - Dehumidifying product

Info

Publication number: WO2003092865A1
Application number: PCT/GB2003/001942
Authority: WO
Inventors: Richard Peter Harbutt; David Bedford
Original assignee: Reckitt Benckiser (Uk) Limited
Priority date: 2002-05-04
Filing date: 2003-05-02
Publication date: 2003-11-13
Also published as: MXPA04010899A; BR0309725A; KR20050030895A; GB0210297D0; AU2003224330A1; ZA200409673B

Abstract

A dehumidifying product comprises a chamber (49) containing a deliquescent agent bounded at least in part by a vapour-permeable membrane (48), and a housing (44). The chamber has a stowed configuration within the housing. In the stowed configuration the chamber is isolated from the surrounding air. The chamber also has an operative configuration in which it is upstanding from the housing and exposed to the surrounding air, to extract water vapour from it.

Description

DEHU IDIFYING PRODUCT

The .present invention relates to a product and method for absorbing water vapour, particularly, although not exclusively, for dehumidifying air in a confined space.

Humidity, or water vapour in air, is often undesirable as water vapour may interfere with the storage of moisture sensitive materials, such as foodstuffs, cosmetics, pharmaceuticals, household goods and clothes, or it may adversely effect the operation of moisture sensitive equipment. This problem may be particularly pronounced in those areas where humidity levels are particularly high, such as those countries having hot humid climates.

It is therefore often desirable to dehumidify air.

Traditional methods for dehumidifying air include the use of mechanical refrigeration equipment and water absorbent materials, such as silica gel.

Typically, methods employing refrigeration equipment involve cooling air to a predetermined temperature below its dew point, so that water condenses from the air and the water may be drained away. Thereafter, the air may be reheated to a predetermined warmer temperature. Techniques including absorbent materials may include continuous operation systems so that water is absorbed by the absorbent in a first cycle and then water desorbed from the absorbent by the application of heat in a second cycle.

Suitably, these techniques suffer from various disadvantages as they typically require bulky and heavy equipment, such as compressors, fans and heaters, which are interconnected by a network of pipes so that water vapour is absorbed continuously from air. Typically, such systems are ill-suited for operation in a confined or limited space. Moreover, the cost associated with such systems may prohibit their use in a domestic environment.

In an attempt to overcome the disadvantages associated with using the aforementioned systems in a confined or limited space, alternative techniques have been developed that include exposing air to an absorbent material. In particular, portable smaller devices comprising a sealed vapour permeable container housing an absorbent material have been employed for dehumidifying air in a limited or confined space, particularly in a domestic environment.

Although absorbents such as silica gel may be employed in these devices, typically silica gel only absorbs up to 30% its weight of water and it is necessary to employ an absorbent having a higher capacity for water vapour absorption to prolong the life and improve the efficiency of the device. Suitably, hygroscopic deliquescent agents, such as calcium chloride, which may absorb 4 to 5 times its weight of water, have been employed in such devices. On absorption of water vapour, the deliquescent agent dissolves to form a liquid.

Although these devices have gone some way to solving the problems associated with absorbing water vapour in a confined or limited space, particularly in a domestic environment, such devices have been bulky and with poor design aesthetics. According to a first aspect the present invention provides a dehumidifying product comprising a chamber containing a deliquescent agent bounded at least in part by a vapour-permeable membrane, and a housing; wherein the chamber has a stowed configuration substantially within or against the housing and an operative configuration in which it is not substantially within or against the housing.

In use, the chamber is preferably upstanding from the housing.^'

Suitably the chamber is retracted from the housing, to move the chamber from its stowed configuration to its operative configuration.

Suitably the housing serves as a stand, by means of which the product may be stood on a surface.

The chamber may have a hook by means of which the product may be hung from a rail, line, hook or the like.

The housing may be adapted to collect liquid which drips from the chamber. In such embodiments the lower region of the chamber may be bounded at least in part by a liquid-permeable membrane. Preferably, the whole membrane is a vapour-permeable liquid-permeable membrane. However in certain embodiments the membrane may be liquid- impermeable; in such embodiments the chamber is designed to retain within it all of the liquid that collects.

Preferably the product is such that when the chamber is in the stowed configuration the chamber is substantially isolated from the surrounding air. In some embodiments this may be achieved by providing the chamber and preferably the dehumidifying product - in an additional water-impermeable barrier, to be removed for use. In other embodiments this may be achieved by virtue of the design of the product per se . For example the chamber may be sealingly retained inside the housing, until needed. It can be moved out of the housing for use.

The chamber may be of flexible form, for example in the form of a sachet. Alternatively the chamber may be of generally rigid form. To that end it may include a self- supporting plastics material. Suitably it may include strips or ribs of a plastics material separated by windows of membrane.

The housing may be of flexible form, form example in the form of a pouch, especially of ^wDoy bag" form. Alternatively a housing may be of generally rigid form, for example of a self-supporting plastics material.

When the housing is of a flexible form it is preferably of a design such that it can stand on a horizontal surface, with the chamber at the top of the housing, in use.

A flexible housing may be in the form of two side walls of flexible material which are joined together along their side edges but spread apart at the bottom of the housing, such that there is a bottom wall of oval or somewhat oval shape. The side walls approach each other in the upper region of the housing. In one embodiment the walls do not meet to close the upper edge of the housing. Rather, they leave a narrow gap and the chamber may be raised through this opening in order to move it from the stowed configuration to the operative configuration.

5. When the chamber is of a flexible material it may be designed to be folded down, to rest against one of the side walls of the housing in the stowed configuration. In another embodiment the chamber - or a web of material between the chamber and the housing - is formed with a 0 series of folds or pleats, such that in the stowed configuration the chamber is retained in a compact condition against the housing. It is lifted from this compact condition in order to put it in the operative configuration. 5

When the housing is of a flexible material the chamber is preferably also of a flexible material.

When the housing' is of a rigid material it may be in 0 the form of a pot or tub which wholly retains the chamber, in the stowed configuration. Preferably the chamber is in some manner lifted substantially out of the housing, to bring it into the operative configuration. Preferably, the chamber is supported by - for example rests upon - the 5 housing, in its operative configuration.

Preferably, the design of the product is such that the chamber is secured to the housing in the operative configuration, to guard against their accidental 0 separation.

When the housing is of a rigid material the chamber is preferably also of a rigid material. The following paragraphs describe different embodiments in which the housing and the chamber of both of a rigid material.

In one embodiment the product has a securement ring, preferably screw-threaded, by means of which the chamber is firmly secured to the housing, in the stowed configuration and/or the operative configuration. To this end the chamber preferably has an outwardly-facing annular flange which engages the circular rim around the mouth of the housing. In the operative configuration the flange of the chamber rests on the rim and the ring secures them together. To achieve this the ring has a cylindrical wall and an inwardly-facing flange depending orthogonally therefrom. In the operative configuration the chamber rests upon, and projects upwardly from, the housing. In the stowed configuration the chamber is inverted. The other face of the flange of the chamber rests on the rim around the mouth of the housing and the ring secures them together, with the flange of the ring trapping the flange of the chamber against the rim. To keep the product fresh the wall of the chamber which is uppermost in the stowed configuration is impermeable to vapour and liquid in the stowed configuration. Preferably it is only temporarily impermeable to vapour and liquid. Suitably it comprises a said membrane which is covered by a peel-off foil, a removable cap, or the like. That wall is to be lowermost in the operative configuration in this embodiment and given that the housing is beneath the chamber and able to collect liquid, the membrane at that wall may suitably be a liquid-permeable membrane. In an alternative embodiment the user may lift the chamber from its stowed position within the housing to its operative position, upstanding from the housing. In this embodiment the chamber is not removed and inverted, to put it into its operative configuration. It is simply lifted. The chamber is preferably of unchanging horizontal cross- section; for example it may be a prism or a cylinder. Means are provided to retain the chamber in its operative configuration. Such means may comprise a screw-thread, a latch or, preferably, a frictional interference fit.

Preferably the chamber in this ^' embodiment is circularly cylindrical. Preferably the upper end of the chamber in this embodiment has attached to it a lid, and there is screw-threaded engagement between the lid and the housing. To move the chamber to its stowed configuration the user therefore releases the lid from the housing by an unscrewing action; and when the screw threads have disengaged, simply lifts the lid, thereby lifting the chamber to its operative configuration. The lid may have a central circular part which can be disengaged from a ring carrying the screw-thread and the chamber may be provided as a removable and replaceable cartridge, such that the cartridge can be accessed on removal of the lid, lifted out through the ring, liquid poured out of the housing, and a fresh cartridge introduced.

In another embodiment in which the chamber may be lifted relative to the housing, the chamber has a portion which projects from the housing, in the stowed configuration. Preferably this portion does not include any area of vapour-permeable membrane. The user may grasp this portion in order to pull it upwards, relative to the housing, thereby exposing vapour-permeable membrane to the air. Once the operative configuration has been reached the chamber can be pulled upwards no further due to the provision of mechanical stop means .

In some embodiments the chamber may be squeezed inwardly by the user, at its lower region in its operative configuration, in order to release retaining parts acting between the lower region of the chamber and the housing, and enable its removal.

Means may be provided for adjusting the rate at which the dehumidifying product absorbs water vapour. This may be the same means by which the chamber is movable between the stowed configuration and the operative configuration; thus the chamber could be used in an. intermediate position of the chamber or even, in certain embodiments, in the stowed configuration, once unwrapped. It should be noted that references herein to "the operative configuration" do not imply that there is only one operative position; generally we use the term "the operative configuration" to refer to the fully extended configuration and/or the configuration for maximum absorbency rate. Often there are other operative configurations possible, less extended and/or giving a lower absorbency rate.

As noted above, in certain embodiments of the present invention the chamber may be removable from the housing. In such embodiments fresh chambers may be provided as refills.

In accordance with a second aspect of the invention there is provided a dehumidifying kit comprising a dehumidifying product of the present invention as defined above, of a type in which the chamber is removable from the housing, and at least one fresh chamber containing a deliquescent agent, isolated from the surrounding air until required.

Preferably the deliquescent agent is able to absorb at least its own weight of water at 25°C. ^'

Preferably, the deliquescent agent forms a liquid or gel on absorption of water vapour, and is such that liquid seeps from it. Preferred deliquescent agents include calcium chloride and/or magnesium chloride as these not only exhibit an acceptable water absorption capacity but they are relatively non-caustic.

Saturation may be determined by pressing on the membrane in order to assess the gel state of the deliquescent agent. Alternatively the deliquescent agent may contain a colour-change agent acting as an indicator of the saturation of the deliquescent agent. In some embodiments in which water drips into the housing this may be visible.

Suitably, the deliquescent agent as defined above may be admixed with other agents selected from a binder, such as starch, a perfume and an antimicrobial agent or combinations thereof.

Preferably the housing and/or chamber comprise a plastics material, preferably a thermoplastics material such as polyvinyl chloride, polyester, polypropylene and polyethylene. When generally rigid they are preferably formed by a moulding process, preferably from a sheet of plastics material (eg by vacuum forming) or from a polymer material in the melt (eg by injection moulding) . In many embodiments an opening is formed in the moulding process or is subsequently formed; and is then closed by the membrane .

Many suitable membranes are commercially available and/or described in literature. Preferably a material is selected that can admit at least 500g, more preferably at least l,000g, most preferably at least 2,000g water vapour/m²/day. Suitable membranes may be of polyethylene, . polypropylene, polyester and polyamide. They may be microporous and may be liquid-permeable or liquid impermeable, as required. Liquid-permeable membranes may be perforate, provided the deliquescent agent is retained.

The membrane may be secured to an adjoining part of the chamber, or to another membrane when the chamber is in the form of a sachet, by an adhesive seal or heat seal.

Preferably the deliquescent agent is in contact with said membrane, in the chamber.

A surface of the product which faces outwards in the stowed configuration is preferably printed, for example with a trade mark, graphics, explanatory wording and the like. Preferably there is no printed secondary packaging. However the dehumidifying product may suitably be wrapped in vapour- and liquid-impermeable packaging up to the point of sale, in order to have the maximum shelf-life and/or utility for the customer. Such packaging can be transparent film. Alternatively in lieu of such a film a peel-off cover strip or foil can be provided over the or each membrane which is exposed to air in use, the cover strip (s) or foil(s) being removed for use.

In accordance with a third aspect of the present invention there is provided a method of absorbing water vapour from a locus, preferably an enclosed locus, the method comprising the steps (in either order) of a) changing a dehumidifying product of the first aspect from its stowed configuration to its operative configuration, and b) locating it in the locus.

The invention will now be further, by way of example, with reference to the accompanying drawings, in which:

Fig. 1 is an expanded perspective view of a first embodiment of dehumidifying product of the present invention;

Fig. 2 is a view corresponding to that of Fig. 1 but with the product shown assembled;

Fig. 3 is an outline side view of the dehumidifying product of Figs. 1 and 2, in a stowed configuration;

Fig. 4 is a corresponding view to that of Fig. 3, with the product in the operative configuration;

Figs. 5A-5D are a series of views of a second embodiment of dehumidifying product, ranging from stowed .(as-sold) (Fig. 5A) to operative, configured for maximum rate of absorption (Fig. 5D) ; Fig. 6 is a schematic side view of a third embodiment of dehumidifying product;

Fig. 7 is a corresponding frontal photographic view;

Fig. 8 is a view of the product of Figs. 6 and 7, in a stowed configuration, for reduced absorbency;

Figs. 9A-9B are respective side sectional views of a fourth embodiment of dehumidifying product, in a stowed configuration (Fig. 9A) and in an operative configuration (Fig. 9B) ;

Figs. 10A-10E are a series of perspective representations showing the steps in reconfiguring the stowed product of Fig. 9A into the operative product of Fig. 9B;

Figs. 11A-11B are- side sectional views of a fifth embodiment of dehumidifying product, respectively in stowed and in operative configurations;

Figs. 12A-12B are perspective photographic-style representations corresponding to those of Figs. 11A-11B;^'

Figs. 13A-13B are side sectional views of a sixth embodiment of dehumidifying product respectively in stowed and operative configurations; and

Figs. 14A-14B are perspective views of the sixth embodiment, with Fig. 14A being an exploded view and Fig. 14B showing the product in its operative configuration. In all the embodiments described a vapour-permeable liquid-permeable membrane 20 of microperforated polyethylene is employed. Sealing of the membrane to itself or to adjacent parts of the chamber can be by an adhesive or by application of heat.

In all the embodiments described the deliquescent agent is calcium chloride in granular form.

The first embodiment of dehumidifying product, shown in Figs. 1-4, comprises a chamber 2 containing a deliquescent agent and, beneath the chamber 2, a housing 4. The housing 4 is in the form of a flexible pouch and comprises two sheets of strong, flexible plastics material 6, 8. The sheets come together at their side and upper edges but are spaced apart elsewhere. Thus, the housing additionally comprises a base wall shown in outline as 10 in Fig. 1. By way of the base wall 10 and the supporting properties of the side walls 6 and 8, the product may be stood on the base wall 10 as shown in Fig. 2.

The chamber 2 is in the form of a flexible sachet, semi-oval in elevation and consisting of two sheets of membrane entrapping the deliquescent agent. The chamber is secured to the upper region of the housing 4. In fact, there is a narrow gap between the sheets 6, 8 at the upper edge of the housing and the chamber 2 is secured in fixed position within this gap, but with the major part of the chamber 2 exposed above the housing.

The sheet material which makes up the housing is vapour- and liquid-impermeable . However the membrane of the chamber 2 is of a liquid- and vapour-permeable material.

The upper region of the chamber 2 has secured to it a hook 12 to facilitate hanging of the product from e.g. a wardrobe rail, if it is not wished to stand it on its base wall 10.

As shown by Figs. 3 and 4 the product has a stowed configuration (Fig. 3) and an operative configuration

(Fig. 4) . In the stowed configuration the hook 12 has been folded against a face of the chamber 2, and the chamber 2 has then been folded against a side wall of the housing 4.

This stowed configuration will typically be how the product is offered for sale. To maintain product quality it can simply be sealed in plastics film.

To use the product it is unwrapped and opened out into its operative configuration of Figs. 2 and 4, in which the hook 12, chamber 2 and housing 4 are generally in line with each other. The user may choose to stand the product on its base wall 10 or to hang it, using hook 12. Water vapour passes through the membrane of chamber 2 and is absorbed by the deliquescent agent within it. When the saturation point of the deliquescent agent is reached liquid water is formed and migrates to the bottom of the chamber. At the bottom of the chamber it passes through the membrane, and drips into the interior space of the housing 4. If it is wished in a related embodiment to ensure that water can under no circumstances pass through the membrane of the chamber in the region above the housing, and then run down the outside of the housing, the upper region of the chamber could have a vapour-permeable liquid-impermeable membrane, with only a lowermost portion of the chamber having the liquid-permeable membrane.

Figs. 5A-5B show a dehumidifying product which is similar in principle to the product of Figs. 1-4. It also has an upper chamber 14 containing a deliquescent agent and a lower housing 16 in which liquid can collect. The housing is of the similar form, in having side walls which come together at their side and upper edges, but not at the bottom of the housing, where there is a separate base wall .

A significant difference from the embodiment of Figs. 1-4 is that the chamber 14 is moveable in sliding manner relative to the housing 16.

The product is sold in the form shown in Fig. 5A, in which the chamber is wholly contained within the housing; indeed, the housing is sealed around it. To commence use the user cuts off an upper strip 18 from the housing, along marker lines provided. The user can then grasp a pull-tab 20 connected to the chamber. The pull-tab can just be seen in Fig. 5B. In this configuration it is nested against the chamber 14. When grasped it may be moved so that it extends upwards from the chamber, as shown in Fig. 5C. The user may then pull the chamber upwards using the pull-tab 20, to the extent required. If the user wishes to have a lesser dehumidifying effect and prolong the lifetime of the product they may pull the chamber only to a position such as that shown in Fig. 50. If they wish to obtain a greater dehumidifying effect they may withdraw the chamber 14 to a greater extent from the housing 16 as shown in Fig. 5D. The product of Figs. 5A-5D is designed only to be stood on a surface. The pull-tab 20 is not intended to be a hanging device. However if wished it could be made in the shape of a hook.

The chamber is disc shaped but could in another embodiment be elongated, more like a "piston" slidable within the "cylinder" represented by the housing.

The third embodiment, of Figs. 6-8, is similar to the first and second embodiments, in that it also comprises a chamber 22 for dehumidifying material, and a housing 24, both of flexible form. Again, the- housing is manufactured such that it can serve as a stand, as well as a liquid collector. The chamber 22 is designed to be configured either in a fully extended configuration, as shown in Fig. 7, or in a stowed configuration, shown in Fig. 8. The- stowed configuration may be adopted for space-efficiency during transportation or at the point of sale, or to reduce the rate of water absorption, or both. In this embodiment the chamber is pleated, so as to be able to adopt a truncated or compressed form, at the top of the housing.

The ■ first, second and third embodiments are all related to products of the type known in the packaging art as "Doy bags" or "Doy packs". The embodiments which will

• now be described are not of "Doy" form. Rather, they are all of rigid form.

Figs. 9A-9B and 10A-10E show a fourth embodiment of dehumidifying product. This embodiment comprises a housing 26 in a form of a pot or tub, having an upper mouth with a circular rim 27; and a chamber 28 containing the deliquescent agent. The housing 26 and chamber 28 are of circular appearance in plan view. The chamber 28 has extending outwardly around its periphery at one end an annular horizontal flange 30. The housing 26 and chamber 28 both comprise plastics mouldings. In the case of the chamber 28 the plastics moulding comprises the flange 30, a circular band 32 at the other end of the chamber and several ribs 34 therebetween. As can clearly be seen in Figs. 9A-9B and 10A-10B, there are windows 36 between the parts just mentioned, and these are closed by a vapour- permeable and liquid-permeable material.

In the stowed configuration shown in Fig. 9A the chamber 28 is inside the housing 26. The flange 30 of the chamber rests on the rim 27 around the mouth of the housing. To secure the two together a threaded ring 38 is secured to the housing. The ring 38 has a knurled cylindrical wall 39 and, orthogonal to and projecting inwardly from the wall, a securement flange 40, to entrap the flange 30 of the chamber against the rim around the mouth of the housing. It will be noted in Fig. 9A that a wall of the chamber is apparently exposed to the external environment. In order to keep the product in optimum ■ condition until it is used this face is covered by a peel- off foil 42, best seen in Fig. 100.

The steps required to configure the product for use will now be described with reference to Figs. 1-0A-10E. The as-sold configuration is shown in. Fig. 10A. This corresponds to Fig. 9A just described. To configure the product for use, the ring 38 is unscrewed, and the chamber lifted from the housing - Fig. 10B. The foil 42 is then removed - Fig. IOC. The chamber is then inverted, and placed again on the housing - Fig. 10D. However this time it does not nest within the housing, but stands upwardly from it. The ring is then placed over the chamber and is screwed onto the housing, once again entapping the flange 30 against the rim around the mouth of the housing - Figs. 9B, 10E.

If wished a spent chamber can be replaced by a refill, water being poured out of the housing at the same time.

The fifth embodiment, to be described with reference to Figs. 11A-11B and 12A-12B is somewhat similar to the fourth embodiment in having generally rigid parts, namely a housing 44 in the form of a pot or tub, and a chamber 46 of moulded plastics form but having windows 48 of. vapour- permeable and liquid-permeable material. The principal difference is that to move the chamber into the operative configuration does not require its removal and inversion; it merely requires a lifting operation.

As best seen in Figs. 12A and 12B the chamber 49 is surmounted by a knurled cap 50. In the stowed configuration the cap is screwed onto a thread 52 formed on the outside of an upper neck of the housing 44. Once the cap has been unscrewed sufficiently it may be lifted to raise the chamber to the operative configuration. It remains there by frictional interference.

As best seen in Fig. 11B, the cap is formed with a removable central upper face 54. The face 54 may be removed by means of, for example, a watch buckle or a blade. The face 54 is a simple press-fit within the cap. Once • the face 54 has been removed access to the chamber is permitted. Thus, it may be removed, and replaced by a fresh chamber. The water collected in the housing may be poured out at this. time.

The sixth embodiment will now be described with reference to Figs. 13A-13B and 14A-14B. It also comprises a generally rigid housing 56 and a generally rigid chamber 58, able to slide out of and into the housing 56. In this embodiment the housing 56 and chamber 58 are generally oval in plan view. In particular the chamber 58 is an oval-section cylinder. As with the fourth and fifth embodiments, the chamber is a plastics moulding but formed with windows 60 for a vapour-permeable and liquid- permeable membrane.

The as-sold configuration is that of Fig. 13A. The chamber is wholly nested within the housing. The uppermost extension of the chamber wall is all that protrudes from the housing. However this portion has opposed finger dimples 62 to facilitate lifting of the chamber, to the position shown in Figs. 13B and 14B. The chamber stays in this position because of frictional interference between the parts.

As with the other embodiments the dehumidifying agent within the chamber absorbs water vapour. Liquid water begins to collect inside the chamber and migrate to the bottom of the chamber, where it can pass through a portion of the membrane (not shown) and drip into the housing 56.

Claims

1. A dehumidifying product comprising a chamber containing a deliquescent agent bounded at least in part by a vapour-permeable membrane, and a housing; wherein the chamber has a stowed configuration substantially within or against the housing and an operative configuration in which it is not substantially within or against the housing.

2. A dehumidifying product according to claim 1 wherein the housing is adapted to collect liquid which drips from the chamber.

3. A dehumidifying product according to claim 1 or 2 ' wherein the chamber is isolated from the surrounding air when in its stowed configuration.

4. a dehumidifying product as claimed in claim 3 wherein the chamber is sealingly retained within the housing in the stowed configuration.

5. A dehumidifying product according to any preceding claim wherein the chamber and the housing are both of flexible form.

6. A dehumidifying product as claimed in claim 5, wherein the housing is a Doy pack.

7. A dehumidifying product as claimed in claim 5 or 6, wherein the chamber is movable relative to the housing in one or more of the following ways translation movement; up and down relative to the housing folding movement; the chamber being folded against a side wall of the housing.

8. A dehumidifying product as claimed in any of claims- 1 to 4, wherein the chamber and the housing are both of substantially rigid form.

9. A dehumidifying product as claimed in claim 8 wherein the housing retains the chamber in the stowed configuration, and the chamber is lifted substantially out of the housing into the operative position.

10. A dehumidifying kit comprising a dehumidifying product of the present invention as defined above, of a type in which the chamber is removable from the housing, and at least one fresh chamber containing a deliquescent agent, isolated from the surrounding air until required.

11. A method of absorbing water vapour from a locus, preferably an enclosed locus, the method comprising the steps (in either order) of a) changing a dehumidifying product as claimed in any of claims 1 to 9 from its stowed configuration to its operative configuration, and b) locating it in the locus .

12. A dehumidifying product or kit substantially as described herein with, reference to the accompanying drawings.

13. A method of absorbing water vapour substantially has described herein with reference to the drawings and description.