DEPOSITS

Description

The present invention relates to an assembly for avoiding the build-up of chalk, lime and other deposits on a surface used in environments subject to dry-wet cycles, said assembly comprising a base part being made of a first material having a first expansion in volume when exposed to moisture or a fluid.

The invention relates to the, typically undesired, deposition of chalk, lime and other deposits on surfaces that are subject to dry-wet cycles. The invention relates to the avoidance of such deposit formation.

It is often the case that water deposits chalk and lime on surfaces, which is undesired, such as on surfaces in dry-wet cycle environments. By dry-wet cycle environment is meant environments, i.e. surfaces, which are exposed to moisture or a fluid for a period of time and afterwards not exposed to moisture or fluid for a period of time.

The chalk and lime formation on surfaces is undesired for a number of reasons. The formation of chalk and lime on surfaces makes the surface visually less attractive. In addition, the formation of chalk and lime may alter and sometimes even completely deteriorate the function of the surface.

When chalk, lime and other deposits are deposited on surfaces, it is known to clean the surfaces, either by mechanical removal or by chemical removal such as for instance by applying a chemical/acidic solution to the surface.

It is an object of the present invention to wholly or partly overcome the above disadvantages and drawbacks of the prior art. More specifically, it is an object to provide an improved assembly which in an expedient manner avoids the build-up of chalk, lime and other deposits on a part of the assembly being periodically exposed to moisture or fluid. The above objects, together with numerous other objects, advantages and features, which will become evident from the below description, are accomplished by a solution in accordance with the present invention by an assembly for avoiding the build-up of chalk, lime and other deposits on a surface used in environments subject to dry-wet cycles, comprising :

- a base part being made of a first material having a first expansion in volume when exposed to moisture or a fluid,

wherein a face part is connected with the base part, the face part being made of a second material having hydrophilic properties, the second material being configured to have an expanded state with a second expansion in volume when exposed to moisture or a fluid, the second expansion in volume being at least 2 % larger than the first expansion in volume, the second material being configured to decrease at least 1.5 % compared to the second expansion in volume in the expanded state when being dried.

The inventor of the present invention has realised that by providing a second material having hydrophilic properties which is configured to expand while being exposed to moisture/fluid and contract again when being dried, chalk, lime and many other deposits (such as paint) have very low breakage points for expansion/contraction and will thus break into pieces if expanded/contracted sufficiently. Hence, it is hereby possible to avoid the normal build-up of chalk, lime and other deposits on surfaces by implementing the present invention where surfaces are periodically exposed to moisture/fluid - i.e. dry-wet cycles.

By the term "dried" is meant that the second material dries out by the moisture/fluid evaporating from the second material, whereby it contracts and returns substantially to the unexpanded state.

The principle of the invention is based on the expansion or contraction of rubber, plastics, gums, resins and polymers with hydrophilic properties when in contact with water (Davidson, R. L, 1980 Handbook of water-soluble gums and resins; Calo, E. & Khutoryanskiy, V. V., 2015 Biomedical applications of hydrogels: A review of patents and commercial products; Traubel, H, 1999 New Materials Permeable to Water Vapor; and references therein).

Furthermore, the second material may comprise rubber, plastic, gum, resin and/or polymer. Rubber, plastic, gum, resin and/or polymer have shown to have high expand/contract capalities when moisture/fluid is absorbed by them/evaporated from them.

The second material may comprise rubber, plastic, gum, resin and polymer with hydrophilic properties, or it may comprise rubber, plastic, gum, resin and polymer to which hydrophilic properties have been added by chemical or physical alterations, including the simple addition of hydrophilic elements to the rubber, plastic, gum, resin or polymer. These second materials expand when in contact with moisture/fluid and contract when the moisture/fluid evaporates.

These rubber, plastic, gum, resin and polymer can be made to expand more than 500 % in volume depending on the modifications, but the inventor has realised that only around 2 % expansion in volume of the second material is required to see an effect on chalk and lime formation on the surface. This defines the levels of hydrophilicity of the materials required, which can be directly tested by observing the expansion of (e.g.) a centimetre cube of the second material after 48 hours of submersion in water.

In addition, the rubber may be natural rubber or synthetic rubber or a mixture thereof.

Moreover, the synthetic rubber may be acrylonitrile-butadiene rubber, carboxylated acrylonitrile-butadiene rubber, hydrogenated acrylonitrile-butadiene rubber, carboxylated hydrogenated acrylonitrile-butadiene rubber, epichlorohydrin rubber, acrylic rubber, ethylene-propylene rubber, chloroprene rubber, butadiene rubber, styrene-butadiene rubber, fluororubber, silicone rubber, urethane rubber, and isoprene-propylene rubber, as well as mixtures thereof.

Furthermore, a super-absorbing polymer (SAP) and/or an emulsifier may be added to the second material for enhancing the hydrophilic properties and thereby the second expansion in volume. By adding a super-absorbing polymer (SAP) and/or an emulsifier to the second material, it is also obtained that the expansion rate is increased, meaning that the second material absorbs moisture/fluid faster and thereby expands quicker. Additionally, bentonite, clay, wood flour, swellable cellulose products, agar, gelatine, swellable polymers like polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, linseed oil, kiselgur and other chemically modified polymers may be added to the second material for enhancing the hydrophilic properties.

For instance, addition of linseed oil to the second material will promote the expansion of the second material when exposed to moisture or a fluid.

Moreover, a desiccant may be added to the second material.

According to the invention the desiccant may be clay, molecular sieves, bentonite, silica, silicagel or Silica or a mixture thereof.

The second material may be thermally conductive.

Furthermore, the face part may coated on the base part.

Also, the face part may be connected with the base part by a chemical binding or mechanical binding.

The base part and the face part may comprise corresponding engagement members which ensure a mechanical binding between them. In some circumstances it is important that the face part is not going to be separated from the base part during the expansion of the second material. In other embodiments, a net or pattern may be arranged between the base part and the face part in order to enhance the connection between them.

The first material may be metal, ceramics, polymer, compound, compositeor similar materials or even a combination thereof.

The first material when exposed to moisture or a fluid may have substantially no expansion.

In an embodiment of the invention, the the second expansion in volume may be at least 20 % larger than the first expansion in volume, the second material being configured to decrease at least 15 % compared to the second expansion in volume when being dried. The second material may expand immediately by contact with moisture or a fluid.

Furthermore, the face part may be partly or fully covering the base part.

The face part may be configured to resist a temperature which is higher than 50 degrees Celsius.

According to an embodiment of the invention, the assembly may be an aerator for a faucet or a tap.

According to another embodiment of the invention, the assembly may be a shower head.

Furthermore, the base part may be a shower head cabinet and the face part may be a nozzle part.

According to yet another embodiment of the invention, the assembly may be a liquid kettle.

The liquid kettle may be electrically heated.

Also, the assembly may be a building panel, such as a roof panel or a facade panel.

Furthermore, the assembly may be a facade of a building.

In addition, the face part may be a gasket.

The present invention also relates to use of the assembly as described above for preventing deposition of chalk, lime and other deposits on surfaces that are subject to dry-wet cycles environments.

The present invention also relates to a method for avoiding the build-up of chalk, lime and other deposits on a surface used in dry-wet cycles, comprising:

- providing an assembly as described above,

- exposing the face part of the assembly to moisture or a fluid for a period of time so that the face part expands, and - stopping the exposure of the face part of the assembly to moisture or a fluid for a period of time so that the face part decreases in expansion.

The present invention is preferably used in connection with water which normally has a content of chalk.

The invention and its many advantages will be described in more detail below with reference to the accompanying schematic drawings, which for the purpose of illustration show some non-limiting embodiments and in which

Figs, la-lc show, in a cross-sectional view, a part of an assembly according to the present invention,

Fig. 2 shows, in a cross-sectional view, an embodiment of the invention wherein the assembly is a shower head, and

Fig. 3 shows, in a cross-sectional view, another embodiment of the invention wherein the assembly is a water kettle.

All the figures are highly schematic and not necessarily to scale, and they show only those parts which are necessary in order to elucidate the invention, other parts being omitted or merely suggested.

Figs, la-lc show, in a cross-sectional view, a sequence of an assembly 1 of the invention. The assembly 1 comprises a base part 2 made of a first material having a first expansion in volume when exposed to moisture or a fluid. The assembly 1 also comprises a face part 3 being connected with the base part 2, the face part 3 being made of a second material having hydrophilic properties, the second material being configured to have an expanded state with a second expansion in volume when exposed to moisture or a fluid, the second expansion in volume being at least 2 % larger than the first expansion in volume, the second material being configured to decrease at least 1.5 % compared to the second expansion in volume in the expanded state when being dried. In Fig. la, the assembly 1 is not exposed to moisture or fluid, and the face part 3 is then in its un-expanded state. In Fig. lb, the face part 3 has been exposed to moisture or fluid, whereby the second material has been absorbing the moisture or fluid so that it expands in volume with a second expansion in volume.

In Fig. lc, the face part 3 is again exposed to the dry cycle of the assembly, whereby the second material is drying up by the moisture or fluid absorbed in the second material evaporating from the second material, so that the second material decreases in expansion and returns to the unexpanded state of the face part 3.

The first material of the base part 2 does substantially not expand when being exposed to moisture or a fluid. The base part 2 may function as a backing layer or support for the face part 3.

By letting the second material expand while it is exposed to moisture/fluid and contract again when it is being dried/evaporated, chalk, lime and many other deposits having very low breakage points for expansion/contraction will thus break into pieces if expanded/contracted sufficiently. Hence, it is hereby possible to avoid the normal build-up of chalk, lime and other deposits on surfaces by implementing the present invention where surfaces are periodically exposed to moisture/fluid - i.e. dry-wet cycles.

Fig. 2 shows, in a cross-sectional view, a schematic drawing of shower head 1. The base part 2 supports the face part 3. The base part 2 has openings through which the face part 3 projects for providing nozzles 4 of the shower head. In the same manner as described above, the second material of the face part 3 is exposed to water 5. During this water exposure the second material absorbs the water and expands. If the water has a chalk content, it will deposit on the face part 3. When the face part 3 is no longer exposed to water, the water present in the second material will start to evaporate, and the second material will decrease in expansion. By the decrease in expansion, the chalk being deposited on the face part 3 will break and stop adhering to the face part 3. Next time the shower head is in use, the chalk may be washed away by the water coming out of the nozzles 4.

Fig. 3 shows, in a cross-sectional view, a schematic drawing of a liquid kettle 1. The inside of the kettle 1 is lined with the face part 3, so that the base part 2 is fully protected from the water 5. The face part 3 may be adhered to the base part 2 by means of an adhesion, or it may be vulcanised on the base part 2. Furthermore, as shown in Fig. 3, the face 3 comprises projections which are configured to engage grooves in the base part so that a mechanical binding between them is obtained. The liquid kettle may comprise an electric heating element (not shown) configured to heat the water in the kettle 1. The electric heating element may also be covered by the face part having the second material.

As is apparent, the present invention may be applied in all technical areas having wet-dry cycle environments.

The present invention may for instance be used for aerators for a faucet or a tap. The face part may be placed near the area of the tap end so that chalk and lime formation may be prevented.

The present invention may also be used in connection with building panels such as facade panels or roof panels. Facade panels and roof panels may be coated with the face part having the second material. Hereby it is obtained that the potential chalk and lime formation may be prevented on the panels.

Other deposits on surfaces subject to dry-wet cycles can be easily washed off with water if treated with the second material of the face part. Examples include graffiti on a wall or even on trains.

The present invention may also be used in connection with tiles to be laid both inside or outside a building. The tiles may be coated with the second material.

The present invention may moreover be used in connection with bathroom elements, such as a sink, a toilet or other plumbing parts, where surfaces exposed to water in a wet-dry cycle may be coated with the second material.

The present invention may furthermore be used in connection with window panes.

Tests have been made for a second material made of silicone rubber with super- absorbing polymers (SAPs) added thereto for enhancing the hydrophilic properties of the second material. The SAP content was 15 %. The test showed that the second material immediately started absorbing the water when being exposed thereto, resulting in the second material expanding in volume. In the same manner it was easily deducible from the tests that when the second material was not exposed to water, the water present in the second material immediately started to evaporate, resulting in the second material starting to contract and decrease in expansion.

Although the invention has been described in the above in connection with preferred embodiments of the invention, it will be evident for a person skilled in the art that several modifications are conceivable without departing from the invention as defined by the following claims.