EP1054819B1 - Device for regulating relative humidity - Google Patents

Abstract

A device for regulating the relative humidity of a closed chamber includes a layer of material capable of being impregnated with liquid and of adsorbing or desorbing vapor of the liquid. The material has on one of its surfaces a membrane which is permeable to vapor but not to liquid. The membrane having an outer surface which is hydrophobic. The adsorbent/desorbent material can be arranged in a sealed tank with an opening for filling with liquid. The device is especially suitable for a paint palette in a chamber having a cover, so that paint can remain on the hydrophobic surface without drying.

Description

The present invention relates to a relative humidity control device.

It is intended in particular to the realization of paint pallets with removable waterproof lid allowing, unlike traditional pallets to maintain the paint as malleable as the exit of the tube without drying, and for several days.

• pots ou conteneurs humidifiant pour la conservation de substances imprégnées d'eau ou de solvants, telles que pâtes, gels, masses et mélanges divers,
• vitrines, valises, boîtes de présentation ou de transport à humidification constante pour la préservation et la conservation d'oeuvres d'art,
• boîtes à cigares, boîtes de conditionnement diverses,
• humidification de produits secs,
• etc.

The device can however be used for many other applications. For example :

• humidifying pots or containers for the preservation of substances impregnated with water or solvents, such as pastes, gels, masses and mixtures,
• showcases, suitcases, boxes of presentation or transport with constant humidification for the preservation and conservation of works of art,
• cigar boxes, various packaging boxes,
• humidification of dry products,
• etc.

To date, there are a large number of systems or products intended to prevent the deterioration of the contents of an enclosure by drying out or, on the contrary, by absorbing too much moisture.

By way of example, mention may be made of the product "ART.SORB" from the company "FUJI SILYSIA Chemical Ltd", in the form of beads, sheets or cassettes able to adsorb and desorb the moisture from the air , and intended to ensure the conservation of works of art.

Patent No. FR 2,656,848 describes a paint bucket having a lid with a seal equipped with a humidifier provided with holes passing through the bucket of the solvent which is impregnated with a sponge disposed in said humidifier.

EP 363194 discloses a device for controlling the relative humidity existing in a pocket envelope consisting of a microporous membrane containing an adsorbent-desorbent material.

The device according to the present invention as defined in claim 1, makes it possible to compensate for the evaporation of water or solvents contained in a product in order to delay, slow down or even stop its drying and hardening in order to maintain its initial state before evaporation. , thus keeping its original malleability. It also makes it possible to re-impregnate a product with water or solvents, if its nature allows it, to restore it to a certain malleability or, conversely, to extract the vapors of water or solvent from the contents of the product. a container.

It consists of a closed enclosure equipped with a relative humidity control system consisting of a material that can be impregnated with liquid and capable of adsorbing or desorbing the vapor of the liquid, this material having on one of its faces a membrane, permeable to vapor but not to liquid, and whose outer face is hydrophobic, the other side of the adsorbent-desorbent material may comprise a membrane permeable to vapor in a single direction to make the self-moistening system or self-desiccant according to the direction of permeability of this membrane.

• la figure 1 représente en coupe verticale une enceinte comportant à sa partie supérieure un dispositif régulateur d'humidité avec réserve de liquide,
• la figure 2 représente dans les mêmes conditions une palette de peinture à couvercle étanche avec dispositif régulateur d'humidité à réserve de liquide disposé au fond de l'enceinte
• et les figures 3 et 4 sont des coupes transversales de régulateurs d'humidité sans réserve de liquide destinés à maintenir une humidité respectivement plus élevée et plus faible que celle régnant en dehors de l'enceinte équipée du dispositif régulateur d'humidité.

In the accompanying drawings, given as non-limiting examples of embodiments of the subject of the invention:

• FIG. 1 represents in vertical section an enclosure comprising at its upper part a humidity control device with liquid reserve,
• FIG. 2 represents, under the same conditions, a paint palette with a leaktight cover with a humidity control device with a liquid reserve arranged at the bottom of the enclosure
• and FIGS. 3 and 4 are cross-sections of humidity controllers with no reserve of liquid intended to maintain a humidity respectively higher and lower than that prevailing outside the enclosure equipped with the humidity control device.

The device, Figures 1 to 4, consists of the combination of a membrane 1 permeable to water vapor having a hydrophobic face 2, and a layer 3 of adsorbent-desorbent material conditioning at a moisture content relative determined, the whole being included in a closed enclosure 4.

The adsorbent-desorbent material 3 may be disposed in a sealed water reservoir with internal (FIG. 2) or external (FIG. 1) filler opening. The material adsorbs the water poured into this reservoir until saturation and desorbs at the desired relative humidity level through the membrane 1. The latter is disposed against one side of the layer 3 so as to have a hydrophobic external free surface . The system compensates for the increase or decrease in relative humidity in proportion to the volume of the enclosure 4 that is to be maintained at a stable relative humidity (Figures 1 and 2).

This arrangement can in particular make it possible to produce a paint pallet 6 consisting of a bottom 7 and a sealed cover 8 articulated or removable. The humidity control device extends over the entire bottom surface and the paint 9 is deposited directly on the hydrophobic surface of the membrane 1, which, combined with the maintenance of moisture inside the enclosure formed by the bottom 7 and the cover 8, allows to keep for a prolonged period the paint 9 in the state in which it was at the exit of the tube. This palette can be used for all water-based paints (acrylic, gouache, watercolor, etc.) (Figure 2). The upper peripheral surface of the water tank may have holes promoting the evaporation of the liquid so as to increase the humidity inside the enclosure.

A porous plate may be interposed between the bottom of the enclosure 4 and the layer 3 of adsorbent-desorbent material communicating with a filling opening or an external reservoir so as to avoid saturation of water in the layer 3.

For some applications, a second inverted regulator device is disposed in the lid and arranged to promote a passage of steam from the inside to the outside. This arrangement makes it possible to moisten certain objects or products deposited on the hydrophobic surface of the membrane 1 of the bottom regulator assembly. It can in particular be applied to treat delicate designs.

In order to improve the diffusion of moisture in the membrane 1, a porous plate, possibly rigid (not shown), may advantageously be provided between said membrane and the adsorbent-desorbent layer 3.

According to an alternative embodiment, the liquid reservoir is arranged below the membrane 1 / adsorbent-desorbent layer 3 assembly and the moisture is transmitted by capillarity to the membrane 1 by means of a sheet of porous material disposed under this layer and extended downwards so as to soak in the liquid. This variant can in particular be used to make enclosures for keeping potted plants for an extended period without watering.

The humidity controller can indifferently be arranged in the lower or upper part of the enclosure. It may in particular be located in the lid 10 of a container such as paint storage pot 11, glue, plastic mass or other products tending to dry. It is advantageous to provide a humidity indicator 12, in contact with the adsorbent-desorbent material and visible from the outside, to know at any time if the amount of water in reserve is sufficient (Figure 1).

If the moisture regulating device is manufactured with the adsorbent-desorbent material layer 3 sealed between a two-way water-vapor permeable membrane 1 on one side, and a second water-vapor permeable membrane 13 in one a single direction directed towards the back of the adsorbent material (arrows 14), the system becomes self-moistening and does not require a reserve of liquid. It acts as a moisture condenser towards the outside of the membrane 1 in two directions (Figure 3).

In contrast, if the direction of permeability of the second membrane 13 'is reversed (arrows 15), the system acts as a permanent desiccator outside the membrane 1 in two directions (Figure 4).

The layer 3 of adsorbent-desorbent material will advantageously consist of unsaturated salts or of a silica gel that can be conditioned for a desired relative humidity level by prolonged passage in an oven maintained at this level, and the membrane 1 made of polytetrafluoroethylene (PTFE ) expanded. This material has a high permeability to gases while being perfectly impervious to liquids. In addition its surface is perfectly hydrophobic and non-staining which makes this material particularly effective in the case of the paint palette 6, which is thus washable and reusable immediately. The membrane 1 can be constituted a very thin film or a porous sheet more or less thick.

The described device can give rise to many applications in different fields.

With a water reserve sealed, it can equip eg cigar boxes, clay conservation boxes, showcases, seed boxes and cuttings, or presentation of flower arrangements, bonsai trees, etc. .

With a second membrane 13, 13 'permeable in one direction, it can be used for the previous applications, without water supply, and also allows the realization of wall panels in contact with the outside and intended for moisture compensation premises too dry (central heating) or too humid. It can also be used as a water trap in hot countries or as a permanent self-dryer for various containers such as cans, cans or sachets.

The system object of the invention with a sealed liquid reserve can also be used to prevent the drying of non-aqueous products and in particular for pallets of varnish paint, or of fast-drying oil paint, or for pots of glycerophtalic paint, varnish, for the conservation of waxes paste. In this case, the liquid reserve is filled with a mixture of water and a proportion tolerable by the membrane 1 of solvent, this membrane, as well as the adsorbent-desorbent material being made from products adapted to the water.

The non-aqueous solvent may also not be diluted in water, the layer 3 of adsorbent material and the membrane 1 then being made of specific materials compatible with this solvent.

The positioning of the various constituent elements gives the object of the invention a maximum of useful effects that had not been obtained so far by similar devices.

Claims (16)

1. Relative humidity regulating device for equipping a closed chamber to compensate for the evaporation of a liquid, such as water or a solvent from its content so as to delay or even stop it from drying out or ensure its re-impregnation with water or solvent or, on the contrary, for extracting water or solvent vapours from said chamber, said device being characterised in that it is constituted by a combination:

   - of a layer (3) of an adsorbent/desorbent material able to be conditioned at a specific percentage of relative humidity;

   - of a membrane (1) impervious to water or liquid solvent but permeable to water or solvent vapour disposed on one of the faces of said layer, with the other face constituting an external hydrophobic surface (2); and

   - of a reserve of said liquid enabling said adsorbent/desorbent material to be impregnated with said liquid, or of a second membrane (13) permeable to vapour in a single direction, placed on the other face of said layer.
2. Device according to claim 1, characterised in that said layer of adsorbent/desorbent material is placed in a liquid reserve or communicates with an external liquid reserve.
3. Device according to claim 1 or claim 2, characterised in that a porous plate is inserted between the membrane (1) and the layer (3) of adsorbent/desorbent material.
4. Device according to one of claims 1 to 3, characterised in that a second porous plate is inserted between the bottom of the closed chamber (4) and the layer (3) of adsorbent/desorbent material, said second plate communicating with a filling opening or an external liquid tank.
5. Device according to claim 4, characterised in that said external liquid tank is placed below said second porous plate which latter is extended downwards so as to soak in the liquid.
6. Device according to claim 5, characterised in that the upper peripheral surface of said liquid tank comprises holes favouring evaporation of the liquid so as to increase humidity inside the closed chamber (4).
7. Device according to one of claims 1 to 6, characterised in that it constitutes a first regulating device placed at the bottom of the chamber cooperating with a second reverse regulating device and placed in the cover and arranged so as to enable a passage of vapour from inside to outside so as to favour the moistening of objects placed on the surface of the membrane (1) of said first regulating device placed at the bottom of the chamber.
8. Device according to claim 1, characterised in that said layer (3) of adsorbent/desorbent material is sealed between a membrane (1) permeable to water vapour in two directions on one face, and a second membrane (13) permeable to water vapour in a single direction directed towards said adsorbent/desorbent material (arrows 14), the system being self-moistening and not comprising any liquid reserve.
9. Device according to claim 1, characterised in that said layer (3) of adsorbent/desorbent material is sealed between a membrane (1) permeable to water vapour in two directions on one face, and a second membrane (13) permeable to water vapour in a single direction directed opposite said adsorbent/desorbent material (arrows 15), the system being a self-drying system.
10. Device according to one of claims 1 to 9, characterised in that it is placed at the bottom of a said closed chamber.
11. Device according to one of claims 1 to 10, characterised in that the object to be moistened or dissected or dried out is placed on said first membrane.
12. Device according to one of claims 1 to 9, characterised in that the outer free surface of said first membrane is hydrophobic.
13. Device according to one of the preceding claims, characterised in that the layer (3) of adsorbent/desorbent material is made up of a silica gel able to be conditioned for a desired percentage of relative humidity.
14. Device according to one of the preceding claims, characterised in that the membrane (1) is made of expanded polyetrafluorethylene (PTFE) having good permeability to gases whilst being fully impermeable to liquids.
15. Use of a device according to one of claims 1 to 14, for regulating the humidity of an object inside one said chamber constituted by a display, packaging or transport box, shop window or suitcase of said object.
16. Use according to claim 15, characterised in that said object is constituted by some paint, glue, plastic bun, clay, cigar, work of art, or plant, sowing, slip, flower arrangement or bonsai tree.

Images