EP2457629A1 - Evaporation device - Google Patents

Abstract

The device (100) has a reservoir (101) containing liquid to be vaporized (111). A heating element (105) i.e. electrically conductive grid, heats the liquid to vaporize the liquid. An annular capillary barrier (106) is arranged in a capillary pumping direction (102) of liquid, downstream from a cylindrical capillary pump (110). The barrier prevents discharge of unvaporized liquid from the device, and has a non-wetting porous component (116) provided with a polymer membrane. The reservoir, the pump and the barrier are arranged in an outer support made of glass, ceramics and/or plastic material. The non-wetting porous component is made of thermally insulating material. The heating element is made of stainless material.

Description

EVAPORATION DEVICE

The present invention relates to an evaporation device comprising an improved capillary pump for the production of steam for a variety of applications and, more particularly, a device for the vaporization of a liquid, comprising a reservoir capable of containing a liquid to vaporizing, a heating element capable of heating liquid in order to vaporize it, and a capillary pump capable of pumping liquid contained in said reservoir towards said heating element by capillary pumping.

TECHNICAL FIELD AND PRIOR ART

International demand WO 2005/049185 describes such a vaporization device comprising a capillary pump for producing and emitting pressurized and non-pressurized steam from a liquid to be vaporized. In particular, international demand WO 2005/049185 discloses a device using a capillary pump having for capillary pumping a wetting porous medium for passively pumping a liquid to be vaporized from a reservoir to a heating or heated element. In its simplest form, this device comprises a liquid inlet to vaporize, a porous vaporization element and an element for thermal transfer.

Other elements such as an insulating element, an element for preheating the liquid to be sprayed, a liquid supply tank and / or a supply system, an integrated or associated heating element, a storage chamber for steam, a heat distributor, an orifice and / or a steam emission element, can also be associated or integrated with this device.

Nevertheless, the vaporization devices comprising a capillary pump according to the prior art have numerous drawbacks. For example, even if the capillary pumping carried out by the capillary pump provided in the device according to the international application WO 2005/049185 is independent of the orientation of said device, a leak will take place and the liquid contained in the tank will flow in the case where the device is used upside down, that is to say with the supply tank in liquid flipped over the capillary pump. Such leakage will occur because the wetting porous medium performing said capillary pump may limit flow rate, but it can not stop it.

The purpose of the present invention is therefore to overcome these disadvantages by providing a device for the vaporization of a liquid comprising a capillary pump capable of operating without leakage regardless of the orientation of the pump while consuming a minimum electrical power during its operation.

SUMMARY OF THE INVENTION

The devices for vaporizing a liquid according to the present invention are provided for the emission of vapor produced from a liquid to be vaporized. In operation of such a device, a liquid to be vaporized, generally having a first temperature and being provided in a low pressure liquid supply tank, is sucked by a capillary pump through capillary forces. The liquid thus sucked is transported to an area of the device serving as a vaporizer. This zone is provided with a capillary barrier, impervious to the liquid and permeable to vapor, thus defining a liquid / vapor or liquid / gas interface. The liquid migrating to this interface is heated to a second temperature, higher than the first temperature and vaporizes. The capillary barrier impervious to liquid and permeable to the vapor allows the expulsion of the latter from the device.

More particularly, the devices for vaporizing a liquid to be vaporized according to the present invention comprise a reservoir capable of containing a liquid to be vaporized, a heating element capable of heating liquid in order to vaporize it, a capillary pump capable of pumping liquid. contained in said reservoir to said heating element by capillary pumping, and a capillary barrier disposed in a direction of capillary pumping of the liquid to be vaporized downstream of the capillary pump, said capillary barrier being able to prevent non-vaporized liquid from escaping of the device.

The present invention thus makes it possible to propose compact devices, allowing a strong integration, and preventing leakage of liquid regardless of the orientation of the devices when in use.

According to one embodiment, said capillary barrier comprises at least one non-wetting porous component. The at least one non-wetting porous component is preferably impervious to said vapor permeable liquid generated from said liquid to be vaporized.

Thus, a desired seal of the devices according to the present invention can be achieved by using a simple and inexpensive component.

Said at least one non-wetting porous component preferably comprises a membrane of polymeric material.

Thus, a robust and reliable non-wetting porous component can be provided.

According to one embodiment, said at least one non-wetting porous component is comparatively little heat conductor required for the vaporization of said liquid to be vaporized. Preferably, said at least one porous non-wetting component is adapted to withstand temperatures higher than the vaporization temperature of the liquid, for example 100 ° C for water at atmospheric pressure, and / or comprises a thermally insulating material.

The present invention thus provides the capillary barrier close to the heating element, allowing a strong integration of the device for the vaporization of a liquid to vaporize and the provision of a compact device, resistant and solid.

Said capillary barrier is preferably arranged in a removable manner.

Thus, the capillary barrier can be exchanged or cleaned easily and quickly thus allowing improved healthiness of the device. In more detail, when using the device for vaporizing a liquid to be vaporized according to the present invention, for example in an air analysis system, the capillary barrier may be located inside the system. analysis and in contact with the air to be treated, while being exchangeable between two successive analyzes thanks to its removability. Thus, the risk of a contamination of the analysis system that could distort the results obtained can easily and effectively be ruled out.

According to one embodiment, said reservoir, said capillary pump and said capillary barrier are provided in the form of stacked disks. Alternatively, at least said capillary pump may be provided in cylindrical form and said capillary barrier in annular form, said capillary barrier surrounding said capillary pump at least partially.

Thus, a compact and rigid device for vaporizing a liquid to be vaporized can be obtained.

Said tank, said capillary pump and said capillary barrier are preferably arranged in an external support. Said outer support preferably comprises glass, ceramic and / or plastic adapted to withstand the heat required for the vaporization of said liquid to be vaporized. In addition, such materials have a low thermal conductivity, which minimizes thermal energy losses: the energy consumption of the device is then minimized.

Thus, an inexpensive external support can be proposed, adapted to maintain the constituent components of the device for the vaporization of a liquid to be vaporized according to the present invention in a predefined structure in a safe and solid manner.

According to one embodiment, said heating element comprises at least one stainless material. Preferably, said heating element is disposed in a capillary pumping direction of said liquid to be vaporized between said capillary pump and said capillary barrier. Alternatively, said heating element may be disposed in a capillary pumping direction of said liquid to be vaporized downstream of said capillary barrier.

The present invention thus provides a reliable heating element at a location of the device for the vaporization of a liquid to vaporize, in the vicinity of which the vaporization of the liquid will take place. Thus, the heat required for the vaporization can be produced exactly at the point of vaporization, thus allowing a minimized consumption of electrical power by the heating element and, therefore, by the device during its operation.

Said heating element is preferably provided in the form of an electrically conductive grid.

Thus, a simple and effective heating element can be realized.

According to one embodiment, said capillary pump comprises at least one porous wetting component permeable to said liquid to be vaporized. The porosity of said at least one non-wetting porous component may be greater than the porosity of said at least one porous wetting component. This allows easy evacuation of steam. But the porosity of said at least one non-wetting porous component may also be lower than the porosity of said at least one porous wetting component. This will be particularly the case if it is desired that the non-wetting porous component constitutes a barrier preventing pollution of the device by the external environment, for example a bacteriological pollution.

Thus, a functional and reliable capillary pump can be proposed.

The at least one porous wetting component may be provided with a porosity gradient, or comprise at least a first porous component and a second porous component, the porosity of said first porous component being greater than the porosity of said second porous component. It is known that a decreasing porosity gradient, obtained by a reduction of the pore diameters, according to the pumping direction of the liquid, increases the pumping pressure.

Thus, a simple, robust and efficient wetting porous component can be realized.

It should be noted that devices for spraying a liquid spray according to the present invention can vaporize any type of liquid, provided that it can be vaporized under appropriate conditions, for example a required heat of vaporization and an associated boiling point. Sprayable liquids may include water, ethanol, perfume compounds, crop treatments, insect repellants and / or attractants, antiseptics, inhalants, and other medical compositions, as well as other liquids for which the Spraying is desirable and / or necessary in order, for example, to accurately measure a vapor such as in a process of producing or depositing a chemical vapor. The advantages of using devices for spraying a liquid spray according to the present invention for vaporizing liquids are that the steam can be produced from the top to the bottom of the device and driven by the airflow. Thus, the reservoir containing the liquid can be located above an associated evaporation zone, so that the hydrostatic pressure is substituted for the mechanical pumps and pressurization systems. In addition, the wetting porous components provide uniform supply of the heating element if the device is inclined. Finally, the outer body of the device is of simple geometry so that it is easy to clean.

An exemplary embodiment and application of a device for vaporizing a liquid to be vaporized according to the present invention as described above is a counter and / or collector of particles included in a gas to be treated, such as air, for example a meter and / or particle collector by semi-wet electrostatic collection. In such counters and / or collectors, the air to be treated is sometimes enriched, or even saturated, with steam so as to cause a magnification of the particles by nucleation, either for meters for counting by optical means, or for collectors for collection purposes. The present invention can be integrated in such devices and improve them by its advantages on the devices of the state of the prior art. An electrostatic collecting device is for example described in the application WO 2007/012447 . The generator The steam according to the invention can be used as a means for producing steam from such an electrostatic collector.

• faire grossir des particules à collecter et ainsi faciliter leur collecte dans un champ électrique intense,
• former un film liquide sur une paroi, qui s'écoule par gravité et entraîne des particules à collecter vers un système d'analyse.

For example, a semi-wet particle collector requires enriching the air with water vapor to:

• make particles to collect collect and thus facilitate their collection in an intense electric field,
• forming a liquid film on a wall, which flows by gravity and causes particles to be collected to an analysis system.

By associating a device for the vaporization of a liquid to vaporize according to the present invention as described above with such a semi-wet particle collector, it would be possible to exploit the flow of air to force the flow of the liquid film on the wall and thus orient the collector differently. In other words, instead of having a flow of air and steam from bottom to top, it would be possible to direct the flow of air and steam from top to bottom using a device for the vaporization of a liquid to be vaporized according to the present invention.

It should nevertheless be noted that the use of the device for the vaporization of a liquid to be sprayed according to the present invention for the production of a counter and / or particle collector has only been described for illustration without limiting the device to such use. On the contrary, a use of the device in many different applications is conceivable, such as for example a use for the production of an apparatus for treatment of the respiratory tract with humidified air.

BRIEF DESCRIPTION OF THE FIGURES

• The figure 1 is a schematic side view diagram illustrating a semi-wet electrostatic collection particle counter and / or collector including a device for vaporizing a liquid to be vaporized according to an embodiment of the present invention.
• The figure 2 is a schematic side view diagram illustrating a device for vaporizing a vaporizing liquid having a capillary pump according to another embodiment of the present invention.
• The figure 3 is a schematic side view diagram illustrating a device for vaporizing a vaporizing liquid having a capillary pump according to yet another embodiment of the present invention with an assembly of disc components.
• The figure 4 is a schematic side view diagram illustrating a device for vaporizing a vaporizing liquid having a capillary pump according to yet another embodiment of the present invention with an assembly of components having a cylindrical geometry.
• The figure 5 is a schematic side view diagram illustrating a particle analysis system having a device for vaporizing a liquid to be vaporized according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The figure 1 shows a counter and / or particle collector by semi-wet electrostatic collection 150 comprising a device for the vaporization of a liquid spray 100 according to a first embodiment of the present invention. An exemplary configuration of a counter and / or particle collector by semi-wet electrostatic collection is described in the international application WO 2007/012447 , the content of which is explicitly referred to and considered to be an integral part of this application. The meter and / or collector 150 is different from the meter and / or collector of the international application WO 2007/012447 essentially by the constitution of its device for the vaporization of a liquid spray 100. Thus, thereafter only the device 100 is described in greater detail, for the sake of brevity and simplicity of the description.

The device for vaporizing a liquid to be vaporized 100 comprises, by way of example, a configuration in the form of stacked disks. During operation of the device 100, a liquid is sucked by one or more capillary pumping layers and then vaporized. The vapor produced is expelled or emitted under pressurized or essentially non-pressurized conditions and can be used directly. For the simplicity of the description below, the device 100 is hereinafter also designated as "evaporation device".

The evaporation device 100 comprises for the illustration a reservoir 101 capable of containing a liquid to be vaporized 111, a heating element 105 capable of heating liquid in order to vaporize it, a capillary pump 110 capable of pumping liquid contained in the reservoir 101 to the heating element 105 by capillary pumping, and a capillary barrier 106 disposed in a capillary pumping direction 102 of the liquid to be vaporized 111 downstream of the capillary pump 110. According to the invention, the capillary barrier 106 is capable of preventing non-vaporized liquid from escaping from the device 100 and preferably comprises at least one non-wetting porous component 116.

The capillary pump 110 is permeable to the liquid to be vaporized 111 and has at least one wetting porous component 103, 104. The pore diameter of this wetting porous component 103, 104 may be larger than the pore diameter of the non-wetting porous component. By way of example, the capillary pump 110 comprises a first porous component 103 and a second porous component 104. The porosity of the first porous component 103 is greater than the porosity of the second porous component 104. In other words, the pores of the second Wet porous component 104 is preferably much smaller than that of the first wetting porous component 103. In addition, the first porous wetting component 103 is preferably thick with respect to the second wetting porous component 104 to provide good thermal insulation between the heating element 105. and the reservoir 101 of the liquid to be vaporized 111. The pumping function of the liquid 111 can be ensured by capillarity p provided that the capillaries or pores of the porous wetting components 103, 104 are of a sufficiently small diameter, preferably less than a millimeter, of a few tenths of a micron to a few hundred microns. Thus, in a preferred embodiment of the invention, the first wetting porous component 103 is provided with a porosity of a few tens of microns or even hundreds of microns and the second porous wetting component 104 is provided with a porosity of a few tenths of a micron to a few microns.

It should nevertheless be noted that the second wetting porous component 104 is purely optional. The evaporation device 100 can therefore be produced according to an embodiment of the present invention without the second wetting porous component 104. In this case, the first wetting porous component 103 constitutes, for example, in itself only the capillary pump 110 according to the invention. the present invention and is then preferably provided with a porosity gradient.

During operation of the evaporation device 100, the first wetting porous component 103 and the second wetting porous component 104 provide a capillary pumping of the spraying liquid 111 from the reservoir 101. A liquid path is established in the direction of the arrow 102, and a heat circulation path is established in the zone comprising the heating element 105.

As has been stated before, one of the advantages of the evaporation device 100 is that it operates passively with respect to capillary pumping and without any leakage regardless of its orientation in use. However, as mentioned above, a wetting porous medium can not stop the flow of a liquid. In the situation where the evaporation device 100 is turned over, the liquid reservoir 101 then being above the wetting porous components 103, 104, the tank 101 would be emptied drop by drop. In such a situation, the wetting porous components 103, 104 would only serve to limit the flow rate by introducing a high pressure drop. To overcome this problem, the evaporation device 100 according to the present invention comprises the non-wetting porous component 116. This non-wetting porous component 116 is impervious to said vapor-permeable liquid 111 generated from said liquid to be vaporized. 111. In this configuration, a liquid / vapor or liquid / air interface is blocked at the interface between the two wetting porous media 103, 104 and non-wetting 116.

In the context of the present invention, a material is said to be "wetting" when a drop placed on it leads to a contact angle of the triple line less than 90 ° according to a commonly accepted definition. Thus, a wetting and porous material is permeable to a liquid, for example the spraying liquid 111. The term "hydrophilic" is reserved for wetting materials with respect to water. A material is said to be "non-wetting" when a drop placed on it leads to a contact angle of the triple line greater than 90 °. A non-wetting material is generally impermeable (or poorly permeable) to a liquid, for example the spraying liquid 111, and may be vapor permeable if porous. The term "hydrophobic" is reserved for non-wetting materials with respect to water.

According to one embodiment, the non-wetting porous component 116 comprises a membrane made of a polymer material, such as, for example, Teflon. Preferably, the non-wetting porous component 116 is comparatively little heat conductor required for the vaporization of said liquid spray 111 and adapted to withstand the vaporization temperatures, for example 100 ° C for water. To do this, the non-wetting porous component 116 may comprise a thermally insulating material.

Located between the first wetting porous component 103 and the nonwetting porous component 116, the heating element 105 directly heats the liquid / vapor or liquid / air interface. Note that the liquid / vapor interface is not necessarily located at the level of the heating element, but can move in the porous medium 103, 104 to the tank 101. In more detail, the heating element 105, located at this interface or in the immediate vicinity of this interface, can vaporize the pumped liquid to this interface. This heating element 105 is advantageously a grid, electrically conductive and preferably made of a stainless material. The heating element 105 may be provided with and electrically connected to a power source (not shown). Crossed by an electric current of this source, it warms up by the Joule effect and heats the interface liquid / vapor or liquid / air where it is located. The energy supplied is thus transmitted directly and only where it is needed. In addition, by choosing porous components 103, 104 and / or 116 in low heat-conducting materials, the heat energy losses are very low. The heating element 105 may for example consist of a grid consisting of stainless steel son diameter 100 microns, the distance between each wire being of the order of magnitude of the diameter, powered by a voltage of a few volts.

More generally, when a source of electric power is available, a heating element that can be heated by electrical energy can be used to provide the heating element 105 to provide the thermal energy required for vaporization. Heating elements based on electrical resistors or having a thermistor or other resistive heating material suitable and suitable for heating, when traversed by an electric current, may be used. The resistive heating material may be designed as a wire, a porous material, a perforated plate or a disc, or may be deposited as a thin or thick film. Preferably, it is incorporated so that the vapor permeability at the vapor emission surface of the vaporizer component, i.e., non-wetting porous component 116, is substantially maintained. Alternatively, the heat can be applied directly to the surface of the non-wetting porous component 116 by means of a resistive heating material in direct contact with or deposited directly on the porous non-wetting component 116.

The constituent components of the evaporation device 100 described above are sufficiently aligned to produce and maintain the liquid flow pathways so that liquid and vapor can travel in or on associated surfaces of different components by capillary pumping. The various wetting porous components 103, 104 constituting the pump are in contact with each other, and are also in contact with the tank 101. In some embodiments, each of the surfaces of the various components comes into close contact with one another. adjacent surface substantially without gaps or voids. The relative thickness, or the volume, of the different components depends on the function that the component provides and the application for capillary pumping.

The components constituting the evaporation device 100 according to the present invention described above may be selected from different materials. Thus, the wetting porous components 103, 104 are preferably made using materials with low heat conductivity such as, for example, a glass sinter, glass beads, glass fibers, sintered or porous stainless steel. Other exemplary porous materials that may be used include porous ceramic, such as alumina grinding material (as provided, for example, by Abrasives Unlimited Inc., San Leandro, Calif.). Other types of absorbents and / or porous materials including cotton, fiberglass (such as EI Dupont de Nemours & Co., Nomextm, Wilmington, Delaware) and the like, known to those skilled in the art, can alternatively be used. These materials have a maximum thermal conductivity of about 0.03 to 3 W / m-K.

The figure 2 shows a sectional view of a second embodiment of the invention of an evaporation device 200. The evaporation device 200 is essentially identical to that described in FIG. figure 1 and comprises a reservoir 201 capable of containing a vaporizing liquid 211, a capillary pump 210 having a first porous wetting component 203 and a second wetting porous component 204, a heating element 206 and a capillary barrier 205 having a porous non-wetting component 215. A capillary pumping associated up to the capillary barrier 205 is designated by an arrow 202.

The difference between the device 200 and the device 100 of the figure 1 consists in arranging the non-wetting porous component 215 below the heating element 206. In more detail, the non-wetting porous component 215 is positioned just above the second wetting porous component 204 and between the latter and the element heating 206.

The arrangement according to the figure 2 allows the heating element 206 to be used to mechanically maintain the various layers of the evaporation device 200 in the form of disks, established by the various constituent components of the device 200, between them. In other words, in the evaporation device 200, the heating element 206 mechanically holds the reservoir 201, the first wetting porous component 203, the second wetting porous component 204 and the non-wetting porous component 205.

The figure 3 shows a sectional view of an evaporation device 300 according to a third embodiment of the present invention. The device 300 consists of an assembly of materials in the form of stacked disks, as illustrated in FIG. figure 1 , and comprises for example a reservoir 301 capable of containing a liquid to vaporize 311. The reservoir 301 is arranged adjacent to a capillary pump 310 having a first wetting and thermally insulating porous medium 304 itself arranged by adjacent to a second wetting and thermally insulating porous medium 305. The capillary pump 310 is arranged below a heating element 307 which is covered by a non-wetting porous component 316 forming a capillary barrier 306. Pumping associated capillary to the capillary barrier 306 is designated by an arrow 302.

The assembly is held by a support 308. The latter comprises an annular upper support 309 (illustrated in FIG. figure 3 on the right and left sides of the device 300 above the porous non-wetting component 316) and an annular lower support 303 (illustrated at the bottom of the figure 3 between the reservoir 301 and the first wetting porous component 304).

The figure 4 shows a sectional view of an evaporation device 400 according to a fourth embodiment of the present invention. The device 400 consists of an assembly of materials and components in a cylindrical geometry and comprises by way of example a reservoir 401 capable of containing a liquid to be sprayed 411, a capillary pump 410 with a first wetting and thermally insulating porous component 403 and a second wetting and thermally insulating porous component 407, a heating element 408 and a capillary barrier 409, which includes, by way of example, a non-wetting porous component 419. Associated capillary pumping to the capillary barrier 409 is designated by arrows 402 and 406.

The first wetting porous component 403 has a cylindrical shape and is held with the cylindrical reservoir 401 by an annular support 404, and a disc-shaped support 405. In more detail, at the bottom of the figure 4 , the reservoir 401 is held by the support 404, which has an annular configuration and illustratively surrounds the end of the reservoir 401. At the top of the figure 4 the first wetting porous component 403 is covered by the disc-shaped support 405.

In addition, the first wetting porous component 403 is surrounded by the second wetting porous component 407 having as an example a tube shape and also held by the support 404, 405. The second wetting porous component 407 is surrounded by the element 408, provided in the form of a spiral and which can serve to maintain the arrangement of the figure 4 in a cylindrical geometry. Finally, the heating element 408 is surrounded by the non-wetting porous component 419 in the form of a tube.

The figure 5 shows a sectional view of a particle analysis system 550 having an evaporation device 500 according to a fifth embodiment of the present invention. The device 500 consists of an assembly of materials in the form of stacked disks, as illustrated in FIG. figure 3 but in comparison with it, turned upside down.

The device 500 comprises, by way of example, a tank 501 capable of containing a liquid to be vaporized 521, the tank 501 being arranged in the figure 5 above a first wetting and thermally insulating porous component 504, which is itself arranged in the figure 5 on top of a second porous wetting and thermally insulating component 505. The two wetting porous components 504, 505 provide for illustration a capillary pump 520, arranged in the figure 5 above a heating element 506 preferably provided in the form of a grid.

The reservoir 501, the first and second wetting porous components 504, 505 and the heating element 506 are held by a support 510. first annular lower support 509 and a second annular lower support 507 in the form of a flange (illustrated in FIG. figure 5 on the right and left sides of the device 500 below the heating element 506), an annular medium support 503 (illustrated in the middle of the figure 5 between the reservoir 501 and the first wetting porous component 504) and an annular upper support 512 having an orifice 511 and being placed or fixed on the device 500 as a cover.

The second symmetrical lower support 507 is provided to hold the reservoir 501, the first and second wetting porous components 504, 505 and the heating element 506 in the form of stacked disks, as illustrated in FIG. figure 3 . Between this second symmetrical lower support 507 and the first symmetrical lower support 509 is provided a removable non-wetting porous component 518 producing a capillary barrier 508. A capillary pumping associated up to the capillary barrier 508 is designated by an arrow 502.

According to one embodiment, the first symmetrical lower support 509 is removable and allows quick and easy replacement and / or cleaning of the removable non-wetting porous component 518, while the other components are maintained during these replacement operations and / or cleaning the component 518 by the second symmetrical lower support 507. As already mentioned above and as visible in the figure 5 , the non-wetting porous component 518 is located inside the analysis system 550 is in contact with the air to be treated. Thus, to avoid the risk of contamination of the device 500, the porous non-wetting component 518 is changeable and / or cleanable between two analyzes.

The present invention has been described above in detail concerning specific embodiments and embodiments with respect to the accompanying figures. These specific modes should not be interpreted as limitations of the scope of the invention, but as exemplary embodiments and embodiments. It should be noted that modifications and substitutions may be made to devices for vaporizing a liquid to be vaporized, as well as to methods of their use, without departing from the scope of the invention.

EXAMPLES Description of an embodiment

The invention may for example be achieved by stacking various components, described above with reference to the figure 1 in a support that is both thermally and electrically insulating and capable of withstanding a temperature of use greater than 100 ° C. For example, a support comprising polycarbonate can be made, resistant to operating temperatures up to approximately 130 ° C max.

In an exemplary embodiment, the first wetting porous component 103 consists of a glass frit 1 mm thick and with a porosity of about 100 to 200 μm. The second wetting porous component 104 consists of a 260 μm thick fiberglass filtration membrane having a filtration threshold of 1.6 μm. The heating element 105 is a wire cloth made of stainless steel wires 97 μm in diameter, and spaced a distance close to this diameter. These stainless steel son are traversed by an electric current and thus constitute the heating element 105. The non-wetting porous component 116 consists of a teflon filtration membrane having a filtration threshold of 20 .mu.m. The membranes used may be, for example, commercially available filters. Their diameters are commonly 25, 47 or 90 mm. The diameter of the evaporation devices is generally between 3 and 20 cm, and their height is between 2 and 20 cm.

Claims (20)

Device (100) for vaporizing a liquid, said device (100) comprising: a reservoir (101) capable of containing a liquid to be vaporized (111), a heating element (105) capable of heating liquid in order to vaporize it , and a capillary pump (110) capable of pumping liquid contained in said reservoir (101) to said heating element (105) by capillary pumping, characterized by a capillary barrier (106) disposed in a capillary pumping direction (102) of liquid spray (111) downstream of the capillary pump (110), said capillary barrier (106) being able to prevent non-vaporized liquid from escaping from the device (100). The device of claim 1, wherein said capillary barrier (106) comprises at least one porous non-wetting component (116). The device of claim 2, wherein said at least one non-wetting porous component (116) is impervious to said vapor permeable (111) liquid generated from said vaporizing liquid (111). The device of claim 2 or 3, wherein said at least one non-wetting porous component (116) comprises a membrane of polymeric material. The device of any one of claims 2 to 4, wherein said at least one non-wetting porous component (116) is comparatively little heat conductor required for the vaporization of said spraying liquid (111). The device of claim 5, wherein said at least one non-wetting porous component (116) is adapted to withstand temperatures above 100 ° C. The device of claim 5 or 6, wherein said at least one non-wetting porous component (116) comprises a thermally insulating material. The device of any one of the preceding claims, wherein said capillary barrier (106) is removably disposed. The device of any one of the preceding claims, wherein said reservoir (101), said capillary pump (110) and said capillary barrier (106) are provided as stacked disks. The device according to any one of claims 1 to 8, wherein at least said capillary pump (410) is provided in cylindrical form and said capillary barrier (409) is provided in annular form, said capillary barrier (409) surrounding said pump capillary (410) at least partially. The device of any of the preceding claims, wherein said reservoir (101), said capillary pump (110) and said capillary barrier (106) are disposed in an outer support (308; 405). The device of claim 11, wherein said outer support (308; 405) comprises glass, the ceramic and / or plastic adapted to withstand the heat required for the vaporization of said liquid spray (111). The device of any one of the preceding claims, wherein said heating element (105) comprises at least one stainless material. The device of any one of the preceding claims, wherein said heating element (105) is disposed in a capillary pumping direction (102) of said liquid to be vaporized (111) between said capillary pump (110) and said capillary barrier (106). ). The device of any one of claims 1 to 13, wherein said heating element (206) is disposed in a capillary pumping direction (202) of said liquid to vaporize (211) downstream of said capillary barrier (205). The device of any of the preceding claims, wherein said heating element (105) is provided in the form of an electrically conductive grid. The device of any one of the preceding claims, wherein said capillary pump (110) comprises at least one porous wetting component (103, 104) permeable to said vaporizing liquid (111). The device of claim 17, wherein the porosity of said at least one non-wetting porous component (116) is greater than the porosity of said at least one porous wetting component (103, 104). The device of claim 17 or 18, wherein said at least one porous wetting component (103, 104) is provided with a porosity gradient, or comprises at least a first porous component (103) and a second porous component (104). ), the porosity of said first porous component (103) being greater than the porosity of said second porous component (104). Counter and / or particle collector by semi-wet electrostatic collection (150) having a device (100) according to any one of the preceding claims.

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