EP0708900B1 - Method and device for evaporating a liquid - Google Patents

Method and device for evaporating a liquid Download PDF

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Publication number
EP0708900B1
EP0708900B1 EP95918659A EP95918659A EP0708900B1 EP 0708900 B1 EP0708900 B1 EP 0708900B1 EP 95918659 A EP95918659 A EP 95918659A EP 95918659 A EP95918659 A EP 95918659A EP 0708900 B1 EP0708900 B1 EP 0708900B1
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EP
European Patent Office
Prior art keywords
substrate
liquid
porous
supplied
water
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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EP95918659A
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German (de)
French (fr)
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EP0708900A1 (en
Inventor
Jacques Pistien
Jean-Louis Giazzi
Robert Desage
Philippe Deblay
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Superba SAS
Cogia SA
Engie SA
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Superba SAS
Gaz de France SA
Cogia SA
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Publication of EP0708900A1 publication Critical patent/EP0708900A1/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B1/00—Methods of steam generation characterised by form of heating method
    • F22B1/28—Methods of steam generation characterised by form of heating method in boilers heated electrically
    • F22B1/287—Methods of steam generation characterised by form of heating method in boilers heated electrically with water in sprays or in films
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B1/00—Methods of steam generation characterised by form of heating method
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B1/00—Methods of steam generation characterised by form of heating method
    • F22B1/28—Methods of steam generation characterised by form of heating method in boilers heated electrically
    • F22B1/284—Methods of steam generation characterised by form of heating method in boilers heated electrically with water in reservoirs
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F6/00—Air-humidification, e.g. cooling by humidification
    • F24F6/02—Air-humidification, e.g. cooling by humidification by evaporation of water in the air
    • F24F6/04—Air-humidification, e.g. cooling by humidification by evaporation of water in the air using stationary unheated wet elements
    • F24F6/043—Air-humidification, e.g. cooling by humidification by evaporation of water in the air using stationary unheated wet elements with self-sucking action, e.g. wicks

Definitions

  • the present invention relates to a method and a device for vaporizing a liquid.
  • DE-C-158 050 is an illustration of this type of steam boiler.
  • Figure 4 of this patent shows the advantage that there may be in using several food trays arranged at different levels elevation, the highest placing the substrate at the horizontal.
  • Tests conducted with such a device show, however, that performance remains poor, and that the amount of liquid in the spray area is quickly too low, that the arrival time of the liquid at this spray zone is often too long.
  • the device of DE-C-158 050 is furthermore bulky, not conducive to industrial achievements of today (high efficiency, compactness, cost of low production for large series, reliability in the weather).
  • Such a device does not provide a continuous vapor release, as long as the direction of the heat flow provided is opposed to the direction of steam output.
  • the object of the invention is to provide a solution to number of the aforementioned drawbacks and offers in in particular a process which can be industrially implemented works under commercially attractive conditions, without exorbitant manufacturing and / or maintenance costs and also offers the advantage of offering flexibility of use, performance and reliability adapted to current needs.
  • the device of the invention provides that the liquid supply means of the substrate considered must include means of implementation liquid pressure to establish a higher pressure at ambient pressure.
  • the knowledge, for a given time interval, of the quantity Q 2 or of the weight of liquid which has entered the substrate (and which therefore has left the container) will make it possible to have the "induced flow" of liquid entering the substrate.
  • the present invention uses the weight of a column of liquid, or we can still force the liquid into the substrate, for example by a pump.
  • the substrate of the present spray device is advisable to make the substrate of the present spray device with thickness between about 0.05 mm and 5 mm, and preferably less than 2 mm.
  • this substrate has a porosity of between about 5% and 90%, and will use a substrate comprising empty volumes of retention of the liquid, so that this liquid can occupy between approximately 5% and 100% of said empty volumes.
  • the use of a substrate almost like a thin porous film has the advantage that the heat flow generated does not find facing it, in or on the surface of the substrate, only a small thickness of liquid to be vaporized, resulting in particularly rapid vapor phase be a few seconds, with a yield that can be particularly high.
  • a characteristic of the invention also provides for increasing the range of flow rate of liquid to be vaporized, supersaturating the substrate with in such a way that part of the liquid flows over a free outer surface thereof, being maintained against this substrate by interfacial tension.
  • a simple way to adjust the flow of liquid flow in the substrate consists of tilt it relative to the horizontal.
  • drip means taking advantage by example for this of capillary pumping of the immersion of a additional porous body in a suitable tank.
  • a pump may also consider using a pump to circulate under pressure the liquid in a local pipe bent between two of the branches of which the substrate porous will have been previously arranged, so that its ends are immersed in the liquid of the tube.
  • the vaporization of the liquid contained in the substrate can be obtained by particular by all or part of the three transfer modes following thermal: radiation, conduction or convection from both flue gas and a source electric, for example, this under conditions of operating which can be both at lower pressure at pressure greater than or equal to the pressure atmospheric, vaporization of many liquids different, such as water, alcohol, liquid petroleum or others may be considered.
  • porous substrate of the invention could be produced from cotton fibers or threads, or even mineral fibers, such as for example glass or quartz fibers, or still metallic, such as wires of steel.
  • substrate formed like a canvas permeable flexible fibrous fabric, or a plate to more rigid structure.
  • the device of the invention may advantageously include two hollow boxes delimiting between them a chimney in which will then circulate the combustion products of the burner, these boxes each containing at least one substrate.
  • FIG. 2 represents an example of the design of a porous "film” 1 with capillary property, made of cotton, of the "honeycomb” type with square mesh 2 of approximately 30 to 50 mm 2 .
  • the latter therefore has a structure integrating empty volumes for retaining the liquid to be vaporized, these volumes being here constituted by the spaces between the wires of the mesh and by the structural empty volumes of the wires themselves.
  • the central part of the substrate 1 illustrated is a weaving of threads of different thicknesses according to the choice of the desired flow capacity. Peripherally, this substrate here consists of wicks three times thicker than those of the central part. Thus, a peripheral buffer for the reserve and diffusion of water is created towards the central parts of the mesh.
  • the choice of substrate permeable is important.
  • its thickness will always be between about 0.05 mm and 5 mm, with porosity to the liquid at spray between about 5 and 90%.
  • Figure 3 is an example of an experimental device feed by pumping a fine porous substrate into the height of a body of water.
  • This device makes it possible to adjust the flow rate of liquid flowing through the effect of gravity right out of the feed tray. It consists of a balance 3, of a container 5 to collect water flowing from the porous "film” 7 and from a water tank 9 into which is submerged the upper part 7a of the porous substrate. To obtain a constant and free flow throughout the width of the porous film passage section, we have indented in 11 the film at its lower part. The measure of flow consists in varying the height h of the body of water tray 9.
  • the table below indicates the characteristics of use of three thicknesses of porous substrates which may be square mesh of the type illustrated in FIG. 2.
  • Density of the substrate heating flux (W / cm2) small mesh 0.2mm 0.104 from 1 to 2.5 medium mesh 0.5mm 0.142 2.5 to 4.5 thick mesh 1 mm 0.196 4.5 to 10
  • FIG. 4 is a diagram which indicates the flow of water flowing in a vertical porous film with small meshes (that is to say of thickness ⁇ 1 mm, for a unitary surface of mesh of the order of 0, 05 mm 2 ) depending on the height of the water body.
  • Curve (A) measures the flow of water which flows freely to the lower part of the substrate.
  • Curve (B) measures the water flow when the same porous film is immersed at its bottom in 2 cm of water.
  • Curve (C) measures the flow rate when the film is pressed against a metal wall without being immersed in its lower part.
  • the steam boiler presented vaporizes water contained in porous films pressed against heat exchange walls 21.
  • heat transfer can be done, as well from a gas ramp type burner, such as 19, with atmospheric air supply, or with supply air, only from one or more radiant burners.
  • a gas ramp type burner such as 19, with atmospheric air supply, or with supply air, only from one or more radiant burners.
  • heat transfer takes place mostly by convection, while in the second it is mainly carried out by radiation.
  • substrates will be used 7a, 7b ... arranged in two distinct rooms 23 defined each by two hollow metal boxes 29 of shape substantially parallelepipedic standing in two planes substantially parallel verticals, being separated from one of the other so as to reserve a space between them intermediate 31 usable as a chimney for the evacuation of fumes that can be produced by the burner, which will preferably be arranged in part bottom of space 31, in a place where space has a truncated pyramid shape going converging in the direction of the smoke evacuation.
  • the chimney is closed laterally by walls (not represented).
  • each partition 21 has been internally fitted with three porous films 7a, 7b, 7c extending in perspective over approximately half the height of the exchange wall, over 3/4 of the remaining height, and on the 1/4 of the highest part.
  • a mesh 33 with large open meshes at a rate of 90% with a mesh surface of 4 cm 2 to, on the one hand, ensure good thermal contact with the substrates and, on the other hand, leave a passage for the steam produced.
  • Each enclosure 29 is also equipped with an upper tank 34 in which is immersed an "upstream" portion of the three porous films which are here of the same thickness. It will be noted that the porous film 7a, in order to reach the top part up to the tank 34, is kept apart from that marked 7b (space d).
  • the entire column of water C1 stored on the thermally protected upper part of the film 7a will serve to supply, under suitable pressure (higher than the ambient pressure prevailing in the enclosure considered), its lower part pressed against the partition 21, therefore fully active in terms of heat exchange and vaporization capacity. It is also the same for the film 7b, but with a column C2 of lesser height practically the entire column being here exposed to the heating flow.
  • the water collected in an appropriate lower reservoir is shown, when the flow rate in the films is greater than that vaporizable by the heat flow. When this excess water reaches a predetermined level, it can be reinjected by a pump into the tanks 34.
  • Figure 7 is a diagram which shows the influence of the number of substrates and the height of water on the vaporization yield depending on the injected power, with either a single porous film of the type aforementioned "small mesh" replacing the two substrates 7a, 7b, or these substrates themselves.
  • the measure consists in varying the height of the water tray 34, it being specified that the tray has in this case been placed approximately 4/5 of the height of the exchange walls.
  • the diagram of Figure 8 shows the influence of the thickness of the substrate (s) on the temperature of the gases leaving the boiler, depending on the variation of its power.
  • a porous film with "small meshes” gives a temperature difference of 120 ° C to 400 ° C while this difference is only from 300 ° C to 370 ° C for a film porous with thick mesh.
  • Figure 9 is a view with cutaway and perspective of an alternative embodiment of a generator of steam use an electrical resistance. It is consists of a cartridge resistor 37 on the surface outside of which a substrate is applied and clamped fibrous appearing as a flexible sleeve 39 sewn in 41 and 43 to form two half-surfaces 45a, 45b which extend towards the lower part of the enclosure 47 while being partially submerged in water at the top in a upper tray 49 whose level could be varied (by a feed pump) and at the bottom in a lower collection tray 51.
  • the enclosure 47 is by elsewhere equipped at its upper part with an outlet for steam 53.
  • the porous film is locally immersed in the spraying water which circulates in closed circuit in a pipeline.
  • This kind of device can operate in different positions by the use of a pump and / or a regulating valve intended to ensure a pressurized supply of the water substrate.
  • the spraying means include a rectangular resistor 59 with a power of 270 Watts.
  • On the resistance is applied and tightened a canvas forming a woven film 61 sewn at 63 and 65 to form a sleeve extending downward, housed and integral with the interior of the lower part 67 of the pipe 69.
  • This sleeve also extends inside the upper part 71 of the same pipe 69.
  • the resistance is housed in a 73 spray enclosure.
  • the vaporization enclosure includes a steam outlet tube 75 and a tube 77 for removing excess water when the water flow too much traffic and flaccid 79 integral with the resistance to be fixed in 81 to the enclosure.
  • a steam outlet tube 75 and a tube 77 for removing excess water when the water flow too much traffic and flaccid 79 integral with the resistance to be fixed in 81 to the enclosure.
  • the circulation of water is provided by a pump 84 whose flow can be adjusted.
  • the outlet 85 of the pipe is provided with a tap 86. On can thus ensure a slight overpressure in the line for the liquid to flow out preferably in the porous film.
  • the vaporization yield in the porous substrate is 20% higher when decreasing the incoming water flow from 57 g / min to 15 g / min.
  • Figure 12 is an example of a drip to feed a vaporizer comparable to that of figure 8.
  • a double woven substrate llla, lllb surrounds, in pendant, an electrical resistance tubular 113, in the lower part of an evaporation enclosure 115.
  • the upper part of the substrate is flared in a "V" shape and rests on two supports. Its liquid supply to evaporating is therefore ensured by a drip, by through two fine woven substrates rectangular 117, 119, hanging vertically and ending at their free lower end with fringes 120 promoting drip and good distribution some cash.
  • the substrates 117, 119 bathe in a liquid supply tank 121, of variable liquid height, filled by a supply not shown.
  • a chimney 123 allows the steam to escape.
  • Figure 13 shows a device for vaporization of liquid using at least one plate in 1 mm thick sintered stainless steel.
  • the liquid is vaporized by the thermal radiation from an electrical resistance.
  • the process of the invention and its examples of realization find their applications in particular in products from the craft sector, the general public, DIY as well as in the processing industries and food.
  • steam generators ranging from a few kg of steam / hour more than a ton / hour.
  • These generators can be used, for example, in catering ovens, the bakery, in consumer stoves, in the cookie industry and pre-baking, in the textile industry for the treatment of fibers, or again, for example, for steam pressing plants, even in biology laboratories for the sterilization. It is also possible, for example, to steam generators for individual irons or with a steam generator, or even for cleaning of floors and walls.
  • heating flux densities usable in the context of the invention can range from a few mW / cm 2 to several tens of W / cm 2 .
  • the device of the invention to operate both under pressure atmospheric that in overpressure or in depression, only the pressurization of the liquid to be provided to ensure the flow conditions sought in the substrate.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Feeding, Discharge, Calcimining, Fusing, And Gas-Generation Devices (AREA)
  • Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
  • Physical Or Chemical Processes And Apparatus (AREA)
  • Chemical Vapour Deposition (AREA)
  • Commercial Cooking Devices (AREA)
  • Motor Or Generator Cooling System (AREA)
  • Sorption Type Refrigeration Machines (AREA)

Abstract

PCT No. PCT/FR95/00656 Sec. 371 Date Apr. 8, 1996 Sec. 102(e) Date Apr. 8, 1996 PCT Filed May 18, 1995 PCT Pub. No. WO95/31674 PCT Pub. Date Nov. 23, 1995A liquid is vaporized by a device having at least one porous substrate exposed to a certain ambient pressure, means for supplying the substrate with liquid in order for it to be loaded with liquid starting from an upstream portion of the substrate, and at least one energy source for heating the substrate so that at least some of the liquid is vaporized. According to the invention, the means for supplying the substrate with liquid may include means for pressurizing the liquid to a pressure greater than ambient pressure, thereby creating a flow-rate greater than the flow-rate induced by capillarity and vaporization of the liquid alone when the substrate is held in a horizontal position. The invention may be applied to the production of water-vaporization equipment, particularly with electrical or gaseous energy supply.

Description

La présente invention concerne un procédé et un dispositif pour la vaporisation d'un liquide.The present invention relates to a method and a device for vaporizing a liquid.

Il est connu que, pour vaporiser un liquide, on peut utiliser une résistance électrique immergée dans une hauteur d'eau relativement importante. Par cette conception, le temps de chauffage du liquide nécessaire pour le vaporiser est relativement long et le rendement de vaporisation est médiocre, surtout en régime séquentiel. C'est par exemple le cas d'un certain nombre de chaudières vapeurs utilisant des gaz de combustion.It is known that, to vaporize a liquid, one can use an electrical resistance immersed in a relatively large water depth. By this design, the heating time of the liquid required to spray it is relatively long and the yield of vaporization is poor, especially in sequential regime. This is for example the case of a number of boilers vapors using combustion gases.

Par le brevet français FR 78 08 201, on connaít toutefois un générateur de vapeur qui, bien qu'utilisant une résistance électrique de chauffage d'un corps poreux immergé à sa base dans une nappe d'eau, a la particularité de vaporiser relativement rapidement l'eau contenue dans ce corps poreux. Le renouvellement de l'eau est assuré par la capacité de pompage du corps poreux. Pour obtenir un optimum de rendement, on règle la hauteur du plan d'eau en fonction de la densité de flux thermique transmis au corps, ceci en fonction de sa capacité de pompage. Ce procédé est applicable à toutes sortes d'énergies, telles que par exemples les gaz de combustion.By the French patent FR 78 08 201, we know however a steam generator which, although using an electrical resistance for heating a porous body immersed at its base in a sheet of water, has the particularity relatively quickly spray the water in it porous body. Water renewal is ensured by the pumping capacity of the porous body. To get a optimum yield, we adjust the height of the water body in function of the density of heat flux transmitted to the body, this according to its pumping capacity. This process is applicable to all kinds of energies, such as by examples of combustion gases.

Si l'utilisation de la capacité de pompage d'un corps poreux peut donc dans certain cas améliorer les performances des chaudières vapeurs, des limites existent, puisque la quantité de liquide contenue dans le corps est décroissante avec la hauteur de pompage. Ce phénomène a pour première conséquence de limiter en pratique à quelques cm la hauteur d'un corps poreux et, pour seconde conséquence, d'entretenir un faible différentiel de variation de hauteur de liquide, si l'on veut obtenir une optimisation de rendement en fonction de la densité du flux de chauffage. If the use of the pumping capacity of a porous body can therefore in some cases improve the performance of steam boilers, limits exist, since the amount of fluid in the body is decreasing with the pumping height. This phenomenon has the first consequence of limiting in practice to a few cm the height of a porous body and, for a second consequence, to maintain a small differential of variation in liquid height, if you want to obtain a yield optimization based on flux density of heating.

On peut d'une certaine manière considérer que le brevet DE-C-158 050 est une illustration de ce type de chaudière à vapeur.We can somehow consider that DE-C-158 050 is an illustration of this type of steam boiler.

Ainsi, dans ce brevet allemand, il est en particulier connu de pourvoir le dispositif de vaporisation de liquide décrit :

  • au moins un substrat poreux (c'est-à-dire à propriété capillaire) exposé à une pression ambiante déterminée,
  • des moyens d'alimentation en liquide du substrat pour qu'il se charge en liquide, par circulation dudit liquide dans le substrat à partir d'une portion amont,
  • au moins une source d'énergie pour chauffer au moins une zone de vaporisation dudit substrat située en aval de la portion amont et le liquide qui la charge, de sorte qu'une partie au moins de ce liquide y soit vaporisée,
Thus, in this German patent, it is in particular known to provide the liquid vaporization device described:
  • at least one porous substrate (that is to say a capillary property) exposed to a determined ambient pressure,
  • means for supplying the substrate with liquid so that it becomes charged with liquid, by circulation of said liquid in the substrate from an upstream portion,
  • at least one energy source for heating at least one vaporization zone of said substrate located downstream of the upstream portion and the liquid which charges it, so that at least part of this liquid is vaporized there,

Toutefois, dans ce brevet, on utilise comme substrat plusieurs mèches alimentées "par l'effet de la force d'aspiration" c'est-à-dire de pompage capillaire desdites mèches.However, in this patent, it is used as substrate several wicks supplied "by the effect of suction force "ie capillary pumping said wicks.

Dans la mesure où, comme indiqué ci-avant, le débit d'une mèche alimentée par pompage capillaire diminue avec la hauteur du plan d'eau d'alimentation, la figure 4 de ce brevet montre l'intérêt qu'il peut y avoir à utiliser plusieurs bacs d'alimention disposés à différents niveaux d'élévation, le plus haut plaçant le substrat à l'horizontale.Insofar as, as indicated above, the flow rate of a wick supplied by capillary pumping decreases with the height of the supply water body, Figure 4 of this patent shows the advantage that there may be in using several food trays arranged at different levels elevation, the highest placing the substrate at the horizontal.

Des essais menés avec un tel dispositif montrent toutefois que le rendement demeure médiocre, et que la quantité de liquide dans la zone de vaporisation est rapidement trop faible, que le temps d'arrivée du liquide à cette zone de vaporisation étant souvent trop long.Tests conducted with such a device show, however, that performance remains poor, and that the amount of liquid in the spray area is quickly too low, that the arrival time of the liquid at this spray zone is often too long.

Le dispositif de DE-C-158 050 est en outre encombrant, peu propice à des réalisations industrielles d'aujourd'hui (rendement élevé, compacité, coût de fabrication peu élevé pour la grande série, fiabilité dans le temps...).The device of DE-C-158 050 is furthermore bulky, not conducive to industrial achievements of today (high efficiency, compactness, cost of low production for large series, reliability in the weather...).

On connaít par le brevet FR-A-2 144 355 une pompe à vide du type à diffusion de vapeurs portant un évaporateur chauffé électriquement constitué d'un tube support le long duquel est admis le liquide à évaporer, et dont l'extrémité inférieure est entourée par au moins une couche de matière poreuse isolante qui est en contact avec la surface interne d'un élément poreux de chauffage électrique, mais à distance dudit tube.We know from patent FR-A-2 144 355 a pump vacuum of the vapor diffusion type carrying an evaporator electrically heated consisting of a support tube along from which the liquid to be evaporated is admitted, and the end of which is bottom is surrounded by at least one layer of material porous insulator which is in contact with the internal surface of a porous electric heating element, but at distance from said tube.

Un tel dispositif ne permet pas de fournir un dégagement continu de vapeur, dans la mesure où la direction du flux de chaleur fournie s'oppose à la direction de sortie de la vapeur produite.Such a device does not provide a continuous vapor release, as long as the direction of the heat flow provided is opposed to the direction of steam output.

L'invention a pour objet d'apporter une solution à nombre des inconvénients susmentionnés et propose en particulier un procédé pouvant être industriellement mis en oeuvre dans des conditions commercialement intéressantes, sans coûts de fabrication et/ou de maintenance exorbitants et offre également l'avantage d'offrir une souplesse d'utilisation, une performance et une fiabilité adaptées aux nécessités actuelles.The object of the invention is to provide a solution to number of the aforementioned drawbacks and offers in in particular a process which can be industrially implemented works under commercially attractive conditions, without exorbitant manufacturing and / or maintenance costs and also offers the advantage of offering flexibility of use, performance and reliability adapted to current needs.

Par la solution de l'invention telle que revendiquée ou établit, pour un régime de vaporisation donné correspondant à des conditions de fourniture d'énergie déterminées, dans le substrat ("capillaire") un débit d'entrée de liquide supérieur au débit d'entrée de liquide induit dans le même substrat, en position alors supposée horizontale de celui-ci, par la capillarité et la vaporisation du liquide, seulement.By the solution of the invention as claimed or established, for a given vaporization regime corresponding to specified energy supply conditions, in the substrate ("capillary") an input flow of liquid greater than the liquid inlet flow rate induced in the same substrate, in the then supposedly horizontal position of this, by capillarity and vaporization of the liquid, only.

Pour obtenir cela, le dispositif de l'invention prévoit que les moyens d'alimentation en liquide du substrat considéré devront comprendre des moyens de mise en pression du liquide pour y établir une pression supérieure à la pression ambiante.To obtain this, the device of the invention provides that the liquid supply means of the substrate considered must include means of implementation liquid pressure to establish a higher pressure at ambient pressure.

Pour éviter toute ambiguïté, on a représenté sur la figure 1 la manière dont on procédera avantageusement pour mesurer le débit induit comme indiqué ci-dessus, "dans le même substrat, par la capillarité et la vaporisation seulement (bien entendu pour les mêmes conditions de fourniture d'énergie), en position alors supposée horizontale du substrat".To avoid any ambiguity, we have shown on the Figure 1 how we will proceed advantageously to measure the induced flow as indicated above, "in the same substrate, by capillarity and vaporization only (of course for the same conditions of energy supply), in a position then assumed horizontal of the substrate ".

Ainsi, on placera tout d'abord à l'horizontale le substrat 7A considéré avec son environnement pour que puisse être négligé en particulier l'effet de la gravité sur les forces de capillarité.Thus, we will first place horizontally the 7A substrate considered with its environment so that especially the effect of gravity can be overlooked on the capillary forces.

Ensuite, on fera baigner une extrémité 7A1 de ce substrat dans un récipient 5A contenant une quantité Q1 de liquide à vaporiser (bien entendu, il s'agira d'un liquide "libre" : simplement une quantité suffisante comme de liquide dont on a rempli un récipient).Then, we will bathe one end 7A 1 of this substrate in a container 5A containing a quantity Q 1 of liquid to be vaporized (of course, it will be a "free" liquid: simply a sufficient quantity as of liquid which has filled a container).

On exposera alors le substrat à une énergie de chauffage donnée fournie par des moyens 19A appropriés, "cette énergie de chauffage" :

  • devant permettre la vaporisation (au moins partielle) du liquide qui aura entre temps "migré" depuis le récipient 5A dans le substrat, suivant la flèche 6,
  • et devant également être reproductible à l'identique sur le dispositif de l'invention y compris la paroi d'échange thermique 21A, si on doit en utiliser une pour réaliser l'invention (si on employe une résistance électrique, on doit utiliser, pour la comparaison, la même résistance alimentée avec la même intensité ; pour le gaz, on doit employer le même brûleur et l'alimenter dans les mêmes conditions).
The substrate will then be exposed to a given heating energy supplied by appropriate means 19A, "this heating energy":
  • having to allow the vaporization (at least partial) of the liquid which will have meanwhile "migrated" from the container 5A into the substrate, according to arrow 6,
  • and must also be reproducible identically on the device of the invention including the heat exchange wall 21A, if one must be used to carry out the invention (if an electrical resistance is used, one must use, for comparison, the same resistance supplied with the same intensity; for gas, the same burner must be used and supplied under the same conditions).

Ayant placé le substrat 7A "sec" dans le récipient, la connaissance, pour un intervalle de temps donné, de la quantité Q2 ou du poids de liquide qui est entrée dans le substrat (et qui a donc quittée le récipient) va permettre de disposer du "débit induit" d'entrée de liquide dans le substrat.Having placed the "dry" substrate 7A in the container, the knowledge, for a given time interval, of the quantity Q 2 or of the weight of liquid which has entered the substrate (and which therefore has left the container) will make it possible to have the "induced flow" of liquid entering the substrate.

On notera que le "débit de liquide sous pression" propre maintenant à l'invention sera favorablement obtenu par l'utilisation de substrats fins (pouvant être avantageusement de l'ordre ou inférieurs à 2 mm d'épaisseur), ce qui ne peut que favoriser l'évacuation de la vapeur. Cette solution est en outre avantageuse en terme de rapidité de mise en phase vapeur du liquide et plus généralement de rendement. Note that the "liquid flow under pressure "proper now to the invention will favorably obtained by the use of fine substrates (may advantageously be of the order of or less than 2 mm thick), which can only favor steam evacuation. This solution is also advantageous in terms of speed of vaporization of the liquid and more generally yield.

Dans la présente invention, pour obtenir l'écoulement souhaité du liquide dans le substrat, on utilise le poids d'une colonne de liquide, ou on pourra encore forcer le liquide dans le substrat, par exemple par une pompe.In the present invention, to obtain the desired flow of the liquid in the substrate, uses the weight of a column of liquid, or we can still force the liquid into the substrate, for example by a pump.

Selon encore une autre caractéristique de l'invention, il est conseillé de réaliser le substrat du présent dispositif de vaporisation avec une épaisseur comprise entre environ 0,05 mm et 5 mm, et de préférence inférieure à 2 mm.According to yet another characteristic of the invention, it is advisable to make the substrate of the present spray device with thickness between about 0.05 mm and 5 mm, and preferably less than 2 mm.

En outre, avantageusement, ce substrat présente une porosité comprise entre environ 5 % et 90 %, et on utilisera un substrat comprenant des volumes vides de rétention du liquide, de telle sorte que ce liquide puisse occuper entre environ 5 % et 100 % desdits volumes vides.In addition, advantageously, this substrate has a porosity of between about 5% and 90%, and will use a substrate comprising empty volumes of retention of the liquid, so that this liquid can occupy between approximately 5% and 100% of said empty volumes.

Ainsi, contrairement aux mèches très épaisses propres aux dispositifs de vaporisation utilisant (très essentiellement) le pompage capillaire, l'utilisation d'un substrat se présentant quasiment comme un film mince poreux offre l'avantage que le flux thermique généré ne trouve face à lui, dans ou en surface du substrat, qu'une faible épaisseur de liquide à vaporiser, avec pour conséquence un passage en phase vapeur particulièrement rapide, pouvant être de quelques secondes, avec un rendement pouvant être particulièrement élevé.So unlike very thick wicks specific to vaporizing devices using (very essentially) capillary pumping, the use of a substrate almost like a thin porous film has the advantage that the heat flow generated does not find facing it, in or on the surface of the substrate, only a small thickness of liquid to be vaporized, resulting in particularly rapid vapor phase be a few seconds, with a yield that can be particularly high.

En particulier, en combinant un substrat réalisé comme un film mince et un débit de liquide répondant aux exigences précitées de l'invention, on a constaté que pour une densité de flux de chauffage constant, il y avait variation du rendement de vaporisation en même temps que l'on faisait varier le débit d'écoulement du liquide dans le substrat. Inversement, à débit de liquide constant, il y avait variation de ce même rendement de vaporisation en même temps que l'on faisait varier la densité de flux thermique. On a également pu obtenir un maximum de rendement de vaporisation pour un état d'équilibre entre le débit de liquide vaporisable entrant dans le "film" constituant le substrat poreux et le débit du flux de chauffage de ce substrat, avec alors une vapeur pratiquement exempte d'humidité.In particular, by combining a substrate realized as a thin film and a flow of liquid meeting the aforementioned requirements of the invention, we have found that for a heating flux density constant, there was variation in vaporization yield at the same time as the flow rate was varied liquid in the substrate. Conversely, at a rate of constant liquid, there was variation of this same yield vaporization while varying the heat flux density. We also got a maximum vaporization yield for a state of balance between the flow of incoming vaporizable liquid in the "film" constituting the porous substrate and the flow of the heating flow of this substrate, with then a vapor practically free from moisture.

Il est par ailleurs apparu que, pour couvrir une large gamme de densités de flux de chauffage, il fallait utiliser différentes épaisseurs de films poreux constituant le substrat, tout en respectant très avantageusement les caractéristiques sus-mentionnées. Pour chacune de ces épaisseurs, et selon la nature de la matière poreuse, il a en particulier été constaté que l'on pouvait obtenir une plage d'utilisation du débit de liquide à vaporiser entre un minimum contenu en transit et la quantité maximale de liquide saturant (voire sursaturant) le film poreux.It also appeared that, to cover a wide range of heating flux densities there had to use different thicknesses of porous films constituting the substrate, while respecting very advantageously the above-mentioned characteristics. For each of these thicknesses, and depending on the nature of the material porous, in particular it was found that one could obtain a range of use of the liquid flow to spray between a minimum content in transit and the maximum amount of saturating liquid (or even supersaturated) the porous film.

Lorsqu'on ne recherche pas particulièrement un très bon rendement de vaporisation, une caractéristique de l'invention prévoit d'ailleurs d'augmenter la plage de débit de liquide à vaporiser, en sursaturant le substrat de telle manière qu'une partie du liquide s'écoule sur une surface extérieure libre de celui-ci, en étant maintenue contre ce substrat par tension interfaciale.When you are not particularly looking for a very good vaporization yield, a characteristic of the invention also provides for increasing the range of flow rate of liquid to be vaporized, supersaturating the substrate with in such a way that part of the liquid flows over a free outer surface thereof, being maintained against this substrate by interfacial tension.

Un moyen simple de réglage du débit d'écoulement de liquide dans le substrat consiste à l'incliner par rapport à l'horizontale.A simple way to adjust the flow of liquid flow in the substrate consists of tilt it relative to the horizontal.

On peut alors créer, comme indiqué ci-avant, une colonne d'eau dans la zone du substrat directement exposée au flux de chauffage et éventuellement au-dessus d'elle, afin de profiter de l'effet de la pesanteur. Lorsque le débit d'écoulement du liquide est supérieur à la densité du flux thermique, on peut récupérer l'excédent de liquide s'écoulant hors de la partie basse du substrat, pour le réinjecter dans sa partie haute.We can then create, as indicated above, a water column in the substrate area directly exposed to the heating flow and possibly above in order to take advantage of the effect of gravity. When the liquid flow rate is higher than the heat flux density, we can recover the excess of liquid flowing out of the lower part of the substrate, to re-inject it into its upper part.

Un moyen supplémentaire d'alimentation en liquide consiste à l'injecter sous pression dans tout ou partie de la section de passage du substrat. On peut ainsi disposer le substrat de manière qu'il baigne à deux extrémités opposées (entre lesquels le liquide à vaporiser coule le long de lui), dans un tube où ledit liquide sera amené par des moyens de circulation forcée. A ce sujet, ce qui suit montre d'abord l'influence de la pression d'une colonne de liquide sur le débit de ce dernier dans le substrat poreux, puis l'influence de l'inclinaison du subtrat sur le même débit de liquide, ceci dans le cas d'espèce d'un substrat poreux constitué par un film par exemple en coton tissé de 0,2 mm d'épaisseur et de 120 mm de largeur.

  • Influence de la hauteur du film poreux sur le débit de liquide : Hauteur du substrat poreux par mm 30 60 90 130 180 Débit d'eau en millilitre par minute 2,3 6,6 11 16 31
  • Influence de l'inclinaison du film poreux sur le débit de liquide : Angle d'inclinaison par rapport à la verticale 0° 15° 65° 75° 90° Débit d'eau en millilitre par minute 5,5 1,7 1,2 0,5 0,3
An additional means for supplying liquid consists in injecting it under pressure into all or part of the passage section of the substrate. It is thus possible to arrange the substrate so that it bathes at two opposite ends (between which the liquid to vaporize flows along it), in a tube where said liquid will be brought by means of forced circulation. On this subject, what follows first shows the influence of the pressure of a column of liquid on the flow of the latter in the porous substrate, then the influence of the inclination of the subtrate on the same flow of liquid , this in the case of a porous substrate consisting of a film for example of woven cotton 0.2 mm thick and 120 mm wide.
  • Influence of the height of the porous film on the liquid flow rate: Height of porous substrate per mm 30 60 90 130 180 Water flow in milliliters per minute 2.3 6.6 11 16 31
  • Influence of the inclination of the porous film on the liquid flow rate: Tilt angle from vertical 0 ° 15 ° 65 ° 75 ° 90 ° Water flow in milliliters per minute 5.5 1.7 1.2 0.5 0.3

Pour alimenter le substrat du dispositif de l'invention avec le débit de liquide souhaité, on peut, conformément à une autre caractéristique de l'invention, utiliser des moyens de goutte à goutte, en profitant par exemple pour cela du pompage capillaire de l'immersion d'un corps poreux supplémentaire dans un réservoir approprié. On peut également songer à utiliser une pompe pour faire circuler sous pression le liquide dans une canalisation localement coudée entre deux des branches de laquelle le substrat poreux aura préalablement été disposé, de telle manière que ses extrémités baignent dans le liquide du tube.To power the substrate of the the invention with the desired liquid flow rate, it is possible, in accordance with another characteristic of the invention, use drip means, taking advantage by example for this of capillary pumping of the immersion of a additional porous body in a suitable tank. We may also consider using a pump to circulate under pressure the liquid in a local pipe bent between two of the branches of which the substrate porous will have been previously arranged, so that its ends are immersed in the liquid of the tube.

On notera également que la vaporisation du liquide contenu dans le substrat peut être obtenue en particulier par tout ou partie des trois modes de transfert thermiques suivants : rayonnement, conduction ou convection provenant tant de gaz de combustion que d'une source électrique, par exemple, ceci dans des conditions de fonctionnement qui peuvent être tant à pression inférieure qu'à pression supérieure ou égale à la pression atmosphérique, la vaporisation de nombre de liquides différents, tels que l'eau, l'alcool, le pétrole liquide ou autres pouvant être envisagée.It will also be noted that the vaporization of the liquid contained in the substrate can be obtained by particular by all or part of the three transfer modes following thermal: radiation, conduction or convection from both flue gas and a source electric, for example, this under conditions of operating which can be both at lower pressure at pressure greater than or equal to the pressure atmospheric, vaporization of many liquids different, such as water, alcohol, liquid petroleum or others may be considered.

Concernant le substrat poreux de l'invention, on notera également qu'il pourrait être réalisé à partir de fibres ou de fils de coton, ou encore de fibres minérales, telles que par exemple des fibres de verre ou de quartz, ou encore métalliques, telles par exemple que des fils d'acier. On peut également envisager réaliser le substrat à partir de matériaux poreux et perméables obtenus par frittage de poudres métalliques.Regarding the porous substrate of the invention, it should also be noted that it could be produced from cotton fibers or threads, or even mineral fibers, such as for example glass or quartz fibers, or still metallic, such as wires of steel. We can also consider making the substrate to from porous and permeable materials obtained by sintering of metal powders.

En pratique deux types de substrat pourront être privilégiés : un substrat formé comme une toile perméable en tissu souple fibreux, ou encore une plaque à structure plus rigide.In practice two types of substrate can be privileged: a substrate formed like a canvas permeable flexible fibrous fabric, or a plate to more rigid structure.

Dans ce qui précède, on a toujours fait référence à l'utilisation d'un seul substrat. Toutefois, l'utilisation de plusieurs substrats est tout à fait prévue. En particulier, on pourra dans un certain nombre de cas tirer avantage à remplacer un substrat unique d'une surface déterminée par plusieurs substrats de dimensions moindres ayant comme surface totale celle dudit substrat unique, chaque substrat de dimensions réduites pouvant en particulier être alimenté par ses propres moyens d'alimentation en liquide, créant ainsi autant de zones de vaporisation pouvant potentiellement être optimisées individuellement.In the above, we have always done reference to the use of a single substrate. However, the use of several substrates is completely planned. In particular, we can in a number of case take advantage of replacing a single substrate of a surface determined by several substrates of dimensions least having as total surface that of said substrate unique, each reduced size substrate being able to individual being self-sustaining liquid supply, creating as many areas of vaporization that can potentially be optimized individually.

Si on utilise plusieurs substrats, on pourra dans certaines applications, prévoir en particulier de faire ces substrats se chevaucher en partie, de manière qu'ils soient écartés les uns des autres sur une partie au moins de leur surface, pour laisser entre eux un espace favorable notamment à la circulation de la vapeur.If we use several substrates, we can in certain applications, provide in particular for make these substrates overlap in part, so that they are separated from each other on at least part of their surface, to leave between them a space favorable in particular to the circulation of the steam.

Egalement, si on utilise au moins deux substrats, on pourra tirer avantage à ce que ces substrats s'étendent de part et d'autre de la source de chauffage en l'encadrant.Also, if we use at least two substrates, we can take advantage of the fact that these substrates extend on either side of the heating source in framing it.

Avant de décrire plus en détail l'invention en relation avec différentes figures d'accompagnement, on notera encore qu'en particulier dans le cas où la source d'énergie comprendra au moins un brûleur à gaz, le dispositif de l'invention pourra avantageusement comprendre deux caissons creux délimitant entre eux une cheminée dans laquelle circuleront alors les produits de combustion du brûleur, ces caissons renfermant chacun au moins un substrat. Before describing the invention in more detail in relationship with different accompanying figures, we will also note that in particular in the case where the source of energy will include at least one gas burner, the device of the invention may advantageously include two hollow boxes delimiting between them a chimney in which will then circulate the combustion products of the burner, these boxes each containing at least one substrate.

Concernant maintenant les dessins joint, en plus de la figure 1, à titre d'exemples non limitatifs, ceux-ci s'organisent comme suit :

  • La figure 2 montre une structure possible de substrat conforme à l'invention,
  • la figure 3 est une vue en perspective d'un montage pour mesurer le débit dans substrat poreux, en fonction de la hauteur de son plan d'eau d'alimentation,
  • la figure 4 est un diagramme montrant la variation du débit d'eau d'un substrat poreux conforme à l'invention en fonction de la hauteur de son plan d'eau,
  • la figure 5 est une vue de côté (flèche V) du générateur de vapeur illustré en perspective partielle, avec arrachement, sur la figure 6,
  • la figure 7 est un diagramme montrant, pour une installation du type de celle des figures 5 et 6, la variation du rendement de vaporisation en fonction de la puissance du chauffage générée, ceci pour plusieurs hauteurs d'eau disponibles et pour deux épaisseurs différentes de substrats poreux,
  • la figure 8 est un diagramme montrant, en fonction de la puissance injectée, l'influence de l'épaisseur du substrat sur la température de sortie des gaz pour une installation toujours conforme à celle des figures 5 et 6,
  • la figure 9 est une vue en perspective avec arrachement d'une chaudière à vapeur utilisant une résistance électrique de type cartouche,
  • les figures 10 et 11 sont des vues en coupe (respectivement suivant les lignes XI-XI et X-X) d'un dispositif de vaporisation électrique équipé de deux substrats poreux baignant localement dans une canalisation où circule de l'eau à vaporiser injectée par l'intermédiaire d'une pompe,
  • la figure 12 est une vue en perspective partielle avec arrachement de l'alimentation par goutte à goutte d'un dispositif conforme à l'invention, et
  • la figure 13 est une vue également en perspective partielle avec arrachement d'un autre générateur produisant de la vapeur par rayonnement thermique d'une résistance.
    • Now concerning the attached drawings, in addition to FIG. 1, by way of nonlimiting examples, these are organized as follows:
  • FIG. 2 shows a possible structure of the substrate in accordance with the invention,
  • FIG. 3 is a perspective view of an assembly for measuring the flow rate in porous substrate, as a function of the height of its supply water body,
  • FIG. 4 is a diagram showing the variation of the water flow rate of a porous substrate according to the invention as a function of the height of its water level,
  • FIG. 5 is a side view (arrow V) of the steam generator illustrated in partial perspective, with cutaway, in FIG. 6,
  • FIG. 7 is a diagram showing, for an installation of the type of that of FIGS. 5 and 6, the variation in the vaporization yield as a function of the heating power generated, this for several heights of water available and for two different thicknesses of porous substrates,
  • FIG. 8 is a diagram showing, as a function of the power injected, the influence of the thickness of the substrate on the gas outlet temperature for an installation always conforming to that of FIGS. 5 and 6,
  • FIG. 9 is a perspective view with cutaway of a steam boiler using an electrical resistance of cartridge type,
  • Figures 10 and 11 are sectional views (respectively along lines XI-XI and XX) of an electric vaporization device equipped with two porous substrates bathing locally in a pipe where circulates the water to be vaporized injected by the through a pump,
  • FIG. 12 is a partial perspective view with cutaway of the drip feed of a device according to the invention, and
  • Figure 13 is also a partial perspective view with cutaway of another generator producing steam by thermal radiation of a resistance.

    • Dans ce qui suit, on ne fera référence qu'à la vaporisation d'eau bien que d'autres liquides pourraient être vaporisés par les mêmes dispositifs.In what follows, we will only refer to the water spray although other liquids could be vaporized by the same devices.

    La figure 2 représente un exemple de conception d'un "film" poreux 1 à propriété capillaire, en coton, type "nid d'abeille" à mailles 2 carrées d'environ 30 à 50 mm2. Comme tous les substrats compatibles avec l'invention, celui-ci présente donc une structure intégrant des volumes vides de retention du liquide à vaporiser, ces volumes étant ici constitués par les espaces entre les fils du maillage et par les volumes vides structuraux des fils eux mêmes. La partie centrale du substrat 1 illustré est un tissage de fils de différentes épaisseurs selon le choix de la capacité d'écoulement désirée. Périphériquement, ce substrat est ici constitué de mèches trois fois plus épaisses que celles de la partie centrale. Ainsi on crée un tampon périphérique de réserve et de diffusion de l'eau vers les parties centrales du maillage.FIG. 2 represents an example of the design of a porous "film" 1 with capillary property, made of cotton, of the "honeycomb" type with square mesh 2 of approximately 30 to 50 mm 2 . Like all substrates compatible with the invention, the latter therefore has a structure integrating empty volumes for retaining the liquid to be vaporized, these volumes being here constituted by the spaces between the wires of the mesh and by the structural empty volumes of the wires themselves. same. The central part of the substrate 1 illustrated is a weaving of threads of different thicknesses according to the choice of the desired flow capacity. Peripherally, this substrate here consists of wicks three times thicker than those of the central part. Thus, a peripheral buffer for the reserve and diffusion of water is created towards the central parts of the mesh.

    Dans l'invention, le choix du substrat perméable est important. Dans ce qui suit, on pourra constater que son épaisseur sera toujours comprise entre environ 0,05 mm et 5 mm, avec une porosité au liquide à vaporiser comprise entre environ 5 et 90 %.In the invention, the choice of substrate permeable is important. In what follows, we can note that its thickness will always be between about 0.05 mm and 5 mm, with porosity to the liquid at spray between about 5 and 90%.

    Pour mieux comprendre les modes de fonctionnement des exemples de réalisation qui vont suivre, la figure 3 est un exemple d'un dispositif expérimental d'alimentation par pompage d'un fin substrat poreux dans la hauteur d'un plan d'eau. Ce dispositif permet d'ajuster le débit du liquide qui s'écoule par l'effet de la pesanteur dès la sortie du bac d'alimentation. Il se compose d'une balance 3, d'un récipient 5 pour recueillir l'eau s'écoulant du "film" poreux 7 et d'un bac 9 à eau dans lequel est immergé la partie haute 7a du substrat poreux. Pour obtenir un débit constant et libre dans toute la largeur de la section de passage du film poreux, on a échancré en 11 le film à sa partie basse. La mesure de débit consiste à faire varier la hauteur h du plan d'eau du bac 9.To better understand the modes of operation of the examples of realization which will follow, Figure 3 is an example of an experimental device feed by pumping a fine porous substrate into the height of a body of water. This device makes it possible to adjust the flow rate of liquid flowing through the effect of gravity right out of the feed tray. It consists of a balance 3, of a container 5 to collect water flowing from the porous "film" 7 and from a water tank 9 into which is submerged the upper part 7a of the porous substrate. To obtain a constant and free flow throughout the width of the porous film passage section, we have indented in 11 the film at its lower part. The measure of flow consists in varying the height h of the body of water tray 9.

    Le tableau ci-après indique les caractéristiques d'utilisation de trois épaisseurs de substrats poreux pouvant être à mailles carrées du type illustré sur la figure 2. Type de substrat poreux en coton épaisseur du substrat Capacité d'enmagasinage d'eau à saturation (g/cm2) Densité du flux de chauffage du substrat (W/cm2) à petites mailles 0,2 mm 0,104 de 1 à 2,5 à mailles moyennes 0,5 mm 0,142 de 2,5 à 4,5 à mailles épaisses 1 mm 0,196 de 4,5 à 10 The table below indicates the characteristics of use of three thicknesses of porous substrates which may be square mesh of the type illustrated in FIG. 2. Type of porous cotton substrate substrate thickness Saturation water storage capacity (g / cm2) Density of the substrate heating flux (W / cm2) small mesh 0.2mm 0.104 from 1 to 2.5 medium mesh 0.5mm 0.142 2.5 to 4.5 thick mesh 1 mm 0.196 4.5 to 10

    La figure 4 est un diagramme qui indique le débit d'eau sécoulant dans un film poreux vertical à petites mailles (c'est-à-dire d'épaisseur < 1 mm, pour une surface unitaire de maille de l'ordre de 0,05 mm2) en fonction de la hauteur du plan d'eau. La courbe (A) mesure le débit d'eau qui s'écoule librement jusqu'à la partie basse du substrat. La courbe (B) mesure le débit d'eau lorsque le même film poreux est immergé à sa partie basse dans 2 cm d'eau. La courbe (C) mesure le débit lorsque le film est plaqué contre une paroi en métal sans être immergé à sa partie basse.FIG. 4 is a diagram which indicates the flow of water flowing in a vertical porous film with small meshes (that is to say of thickness <1 mm, for a unitary surface of mesh of the order of 0, 05 mm 2 ) depending on the height of the water body. Curve (A) measures the flow of water which flows freely to the lower part of the substrate. Curve (B) measures the water flow when the same porous film is immersed at its bottom in 2 cm of water. Curve (C) measures the flow rate when the film is pressed against a metal wall without being immersed in its lower part.

    Ainsi, selon les conditions d'utilisation du substrat, on peut faire varier le débit du liquide qui y coule dans un rapport de 1 à 8 selon la courbe (A), dans un rapport de 1 à 5, courbe (B), et voisin de ce dernier, courbe (C), quand le film poreux est plaqué contre une paroi d'échange.Thus, according to the conditions of use of the substrate, we can vary the flow rate of the liquid which flows in a ratio of 1 to 8 according to curve (A), in a ratio of 1 to 5, curve (B), and neighbor of the latter, curve (C), when the porous film is pressed against a exchange wall.

    Aux figures 5 et 6, la chaudière à vapeur présentée vaporise de l'eau contenue dans des films poreux plaqués contre des parois d'échange thermique 21. Dans ce type de chaudière, le transfert thermique peut se faire, aussi bien à partir d'un brûleur type rampe à gaz, tel que 19, à alimentation d'air atmosphérique, ou à air soufflé, qu'à partir d'un ou de plusieurs brûleurs radiants. Dans le premier cas, le transfert thermique s'effectue majoritairement par convection, tandis que dans le second il s'effectue majoritairement par rayonnement.In Figures 5 and 6, the steam boiler presented vaporizes water contained in porous films pressed against heat exchange walls 21. In this type of boiler, heat transfer can be done, as well from a gas ramp type burner, such as 19, with atmospheric air supply, or with supply air, only from one or more radiant burners. In the first case, heat transfer takes place mostly by convection, while in the second it is mainly carried out by radiation.

    De préférence, on utilisera plusieurs substrats 7a, 7b...disposés dans deux chambres 23 distinctes définies chacune par deux caissons métalliques creux 29 de forme sensiblement parallélépipédique se dressant dans deux plans verticaux sensiblement parallèles, en étant écartés l'un de l'autre de manière à réserver entre eux un espace intermédiaire 31 utilisable comme cheminée pour l'évacuation des fumées pouvant être produites par le brûleur, lequel sera de préférence disposé en partie inférieure de l'espace 31, en un endroit où l'espace présente une forme en tronc de pyramide allant en convergeant dans le sens de l'évacuation des fumées. La cheminée est fermée latéralement par des parois (non représentées).Preferably, several substrates will be used 7a, 7b ... arranged in two distinct rooms 23 defined each by two hollow metal boxes 29 of shape substantially parallelepipedic standing in two planes substantially parallel verticals, being separated from one of the other so as to reserve a space between them intermediate 31 usable as a chimney for the evacuation of fumes that can be produced by the burner, which will preferably be arranged in part bottom of space 31, in a place where space has a truncated pyramid shape going converging in the direction of the smoke evacuation. The chimney is closed laterally by walls (not represented).

    En l'espèce, chaque cloison 21 a été intérieurement équipée de trois films poreux 7a, 7b, 7c s'étendant perspectivement sur environ la moitié de la hauteur de la paroi d'échange, sur les 3/4 de la hauteur restante, et sur le 1/4 de la partie la plus haute. Sur chaque film poreux est appliqué un grillage 33 à larges mailles ouvertes à un taux de 90 % avec une surface de mailles de 4 cm2 pour, d'une part, assurer un bon contact thermique aux substrats et, d'autre part, laisser un passage pour la vapeur produite. Chaque enceinte 29 est également équipée d'un bac supérieur 34 dans lequel est immergée une portion "amont" des trois films poreux qui sont ici de même épaisseur. On notera que le film poreux 7a, pour parvenir en partie haute jusqu'au bac 34, est maintenu écarté de celui repéré 7b (espace d). Ainsi, toute la colonne d'eau C1 enmagasinée sur la partie haute thermiquement protégée du film 7a va servir à alimenter sous pression convenable (supérieure à la pression ambiante régnant dans l'enceinte considérée) sa partie inférieure plaquée contre la cloison 21, donc pleinement active en termes d'échange thermique et de capacité de vaporisation. Il en est d'ailleurs de même pour le film 7b, mais avec une colonne C2 de moindre hauteur pratiquement toute la colonne étant ici exposée au flux de chauffage. A la partie basse de chacune des enceintes, on a figuré en 35 l'eau recueillie dans un réservoir inférieur approprié, lorsque le débit d'écoulement dans les films est supérieur à celui vaporisable par le flux thermique. Lorsque cette eau exécendaire atteint un niveau prédéterminé, elle peut êre réinjectée par une pompe dans les bacs 34.In the present case, each partition 21 has been internally fitted with three porous films 7a, 7b, 7c extending in perspective over approximately half the height of the exchange wall, over 3/4 of the remaining height, and on the 1/4 of the highest part. On each porous film is applied a mesh 33 with large open meshes at a rate of 90% with a mesh surface of 4 cm 2 to, on the one hand, ensure good thermal contact with the substrates and, on the other hand, leave a passage for the steam produced. Each enclosure 29 is also equipped with an upper tank 34 in which is immersed an "upstream" portion of the three porous films which are here of the same thickness. It will be noted that the porous film 7a, in order to reach the top part up to the tank 34, is kept apart from that marked 7b (space d). Thus, the entire column of water C1 stored on the thermally protected upper part of the film 7a will serve to supply, under suitable pressure (higher than the ambient pressure prevailing in the enclosure considered), its lower part pressed against the partition 21, therefore fully active in terms of heat exchange and vaporization capacity. It is also the same for the film 7b, but with a column C2 of lesser height practically the entire column being here exposed to the heating flow. At the bottom of each of the enclosures, the water collected in an appropriate lower reservoir is shown, when the flow rate in the films is greater than that vaporizable by the heat flow. When this excess water reaches a predetermined level, it can be reinjected by a pump into the tanks 34.

    La figure 7 est un diagramme qui montre l'influence du nombre de substrats et de la hauteur d'eau sur le rendement de vaporisation en fonction de la puissance injectée, avec soit un seul film poreux du type précité "à petites mailles" remplaçant les deux substrats 7a, 7b, soit ces substrats eux mêmes. Pour chaque cas, la mesure consiste à faire varier la hauteur du plan d'eau du bac 34, étant précisé que le bac a en l'espèce été placé environ aux 4/5 de la hauteur des parois d'échange.Figure 7 is a diagram which shows the influence of the number of substrates and the height of water on the vaporization yield depending on the injected power, with either a single porous film of the type aforementioned "small mesh" replacing the two substrates 7a, 7b, or these substrates themselves. For each case, the measure consists in varying the height of the water tray 34, it being specified that the tray has in this case been placed approximately 4/5 of the height of the exchange walls.

    Sur l'une des courbes, pour un corps poreux unique et en référence à une hauteur d'eau de H-9 mm par rapport à la hauteur maximale H autorisée jusqu'au bord supérieur du bac, on constate une augmentation de rendement de 0,30 g/Wh à 0,8 g/Wh, puis une diminution de celui-ci jusqu'à 0,65 g/Wh, lorsque l'on fait varier la puissance injectée de 1,2 Kw à 2,4 Kw.On one of the curves, for a porous body unique and with reference to a water height of H-9 mm by relative to the maximum height H authorized up to the edge upper part of the tank, there is an increase in yield from 0.30 g / Wh to 0.8 g / Wh, then a reduction thereof up to 0.65 g / Wh, when the power is varied injected from 1.2 Kw to 2.4 Kw.

    Lorsque l'on augmente encore la puissance, et que l'on augmente également la hauteur d'eau à H-4 mm, on observe une même forme de courbe (repéré par des losanges), avec un rendement augmentant encore jusqu'à 3,2 Kw, puis une baisse de celui-ci à 3,4 Kw. Cette baisse de rendement est encore plus importante si l'on se place à H-2 mm, pour atteindre la valeur de 0,9 g/Wh.When the power is further increased, and that we also increase the water height to H-4 mm, we observes the same shape of curve (marked by diamonds), with a yield increasing further up to 3.2 Kw, then a drop of it to 3.4 Kw. This drop yield is even more important if we look at H-2 mm, to reach the value of 0.9 g / Wh.

    Par la mise en place de deux corps poreux, en ramenant la hauteur d'eau à H-9 mm, on augmente encore le rendement jusqu'à 1,10 g/Wh pour une puissance de 4 Kw, pour ensuite conserver un rendement voisin de cette puissance jusqu'à H-2 mm de hauteur d'eau.By the establishment of two porous bodies, in reducing the water height to H-9 mm, we further increase the yield up to 1.10 g / Wh for a power of 4 Kw, to then keep a yield close to this power up to H-2 mm water height.

    Ainsi, il faut ajuster la hauteur d'eau en fonction de la puissance de la source thermique lorsque l'on veut obtenir un optimum de rendement. Par contre, au-delà de cet optimum le rendement diminue lorsque l'on augmente la puissance, ceci du fait d'un débit trop faible de liquide dans le substrat. On constate encore que le rendement de vaporisation augmente lorsque l'on dispose deux substrats pour une même surface d'échange.So you have to adjust the water height by function of the power of the heat source when we want to obtain an optimum yield. However, beyond from this optimum the yield decreases when increases the power, this due to a too low flow liquid in the substrate. We also see that the vaporization efficiency increases when available two substrates for the same exchange surface.

    On constate encore, qu'à puissance pratiquement constante de 2,4 Kw, le rendement de vaporisation passe de 0,6 g/Wh à 0,8 g/Wh, soit un gain de 30 % sur le rendement de la chaudière. Ce gain est obtenu lorsque l'on fait varier la hauteur d'eau de H-2 mm à H-4 mm, puis à H-9 mm.We can still see that at practically power constant of 2.4 Kw, the vaporization efficiency goes from 0.6 g / Wh to 0.8 g / Wh, a 30% gain in yield of the boiler. This gain is obtained when we make vary the water height from H-2 mm to H-4 mm, then to H-9 mm.

    Pour une chaudière à vapeur correspondant à celle des figures 5 et 6, le diagramme de la figure 8 montre l'influence de l'épaisseur du (des) substrat(s) sur la température des gaz en sortie de la chaudière, ceci en fonction de la variation de sa puissance. Dans ce genre de mesure du transfert thermique, un film poreux à "petites mailles" donne un écart de température de 120°C à 400°C tandis que cet écart est que de 300°C à 370°C pour un film poreux à mailles épaisses. For a steam boiler corresponding to that of Figures 5 and 6, the diagram of Figure 8 shows the influence of the thickness of the substrate (s) on the temperature of the gases leaving the boiler, depending on the variation of its power. In this kind of measurement of heat transfer, a porous film with "small meshes "gives a temperature difference of 120 ° C to 400 ° C while this difference is only from 300 ° C to 370 ° C for a film porous with thick mesh.

    La figure 9 est une vue avec arraché et en perspective d'une variante de réalisation d'un générateur de vapeur utilisation une résistance électrique. Il se compose d'une résistance à cartouche 37 sur la surface extérieur de laquelle est appliqué et serré un substrat fibreux se présentant comme un manchon souple 39 cousu en 41 et 43 pour former deux demi-surfaces 45a, 45b qui s'étendent vers la partie basse de l'enceinte 47 en étant immergées partiellement dans l'eau en partie haute dans un bac supérieur 49 dont on pourrait faire varier le niveau (par une pompe d'alimentation) et en partie basse dans un bac inférieur 51 de collecte. L'enceinte 47 est par ailleurs équipée à sa partie supérieure d'une sortie pour la vapeur 53.Figure 9 is a view with cutaway and perspective of an alternative embodiment of a generator of steam use an electrical resistance. It is consists of a cartridge resistor 37 on the surface outside of which a substrate is applied and clamped fibrous appearing as a flexible sleeve 39 sewn in 41 and 43 to form two half-surfaces 45a, 45b which extend towards the lower part of the enclosure 47 while being partially submerged in water at the top in a upper tray 49 whose level could be varied (by a feed pump) and at the bottom in a lower collection tray 51. The enclosure 47 is by elsewhere equipped at its upper part with an outlet for steam 53.

    Avec ce type de chaudière à résistance électrique, on a réalisé le même genres de mesures que sur la chaudière à gaz des figures 5 et 6. Chacun des tableaux ci-après montre, à débit d'eau constant, le rendement de vaporisation en faisant varier la densité de flux thermique pour quatre épaisseurs de film poreux. 1) Film poreux épaisseur 0,2 mm Densité de flux en W/cm2 2,50 3,30 5,00 6,10 6,90 8 Rendement de vaporisation g/Wh 1,02 1,05 1,24 1,14 2) Film poreux épaisseur 1 mm Densité de flux en W/cm2 2,50 3,30 5,00 6,10 6,90 8 Rendement de vaporisation 0,89 1,04 1,16 1,20 1,24 1,28 3) Film à mèches parallèles épaisseur 2 mm Densité de flux en W/cm2 2,50 3,30 5,00 6,10 6,90 8 Rendement de vaporisation 0,85 1,02 1,14 1,17 1,18 1,17 4) Film à mèches parallèles épaisseur 4 mm Densité de flux en W/cm2 2,50 3,30 5,00 6,10 6,90 8 Rendement de vaporisation 0,85 1,02 1,10 1,11 1,10 1,08 With this type of electric resistance boiler, the same kinds of measurements were carried out as on the gas boiler in FIGS. 5 and 6. Each of the tables below shows, at constant water flow rate, the vaporization yield by making vary the heat flux density for four thicknesses of porous film. 1) 0.2 mm thick porous film Flux density in W / cm2 2.50 3.30 5.00 6.10 6.90 8 Vaporization yield g / Wh 1.02 1.05 1.24 1.14 2) 1 mm thick porous film Flux density in W / cm2 2.50 3.30 5.00 6.10 6.90 8 Vaporization efficiency 0.89 1.04 1.16 1.20 1.24 1.28 3) Film with parallel wicks, thickness 2 mm Flux density in W / cm2 2.50 3.30 5.00 6.10 6.90 8 Vaporization efficiency 0.85 1.02 1.14 1.17 1.18 1.17 4) Film with parallel wicks, thickness 4 mm Flux density in W / cm2 2.50 3.30 5.00 6.10 6.90 8 Vaporization efficiency 0.85 1.02 1.10 1.11 1.10 1.08

    Ainsi, pour les mêmes variations de densité de flux thermique, on observe une variation du rendement de vaporisation de 20 % pour une épaisseur de 0,2 mm, de 40 % pour une épaisseur de 1 mm, de 30 % pour une épaisseur de 2 mm et de 25 % pour une épaisseur de 4 mm.So, for the same density variations of heat flux, there is a variation in the efficiency of vaporization of 20% for a thickness of 0.2 mm, of 40% for a thickness of 1 mm, 30% for a thickness of 2 mm and 25% for a thickness of 4 mm.

    Dans le cas d'un substrat poreux de 1 mm d'épaisseur, à l'optimum de rendement de 1,28 W/cm2, on observe qu'il n'y a pratiquement plus d'écoulement de liquide à la partie basse du substrat (en supposant celui-ci disposé verticalement). Il y a alors équivalence entre la quantité de liquide vaporisable entrant dans le film poreux et le débit de la source thermique, pour une densité de flux de 8 W/cm2.In the case of a porous substrate 1 mm thick, at the optimum yield of 1.28 W / cm 2 , it is observed that there is practically no more liquid flow at the bottom of the substrate (assuming it is arranged vertically). There is then equivalence between the quantity of vaporizable liquid entering the porous film and the flow rate of the thermal source, for a flux density of 8 W / cm 2 .

    Sur les figures 10 et 11, le film poreux est localement immergé dans l'eau à vaporiser qui circule en circuit fermé dans une canalisation. Ce genre de dispositif peut fonctionner dans différentes positions par l'utilisation d'une pompe et/ou d'un robinet de réglage ayant pour but d'assurer une alimentation sous pression du substrat en eau. Les moyens de vaporisation comprennent une résistance rectangulaire 59 d'une puissance de 270 Watts. Sur la résistance est appliquée et serrée une toile formant un film tissé 61 cousu en 63 et 65 pour former un manchon s'étendant vers le bas, logé et solidaire de l'intérieur de la partie basse 67 de la canalisation 69. Ce manchon s'étend également à l'intérieur de la partie haute 71 de la même canalisation 69. La résistance est logée dans une enceinte 73 de vaporisation. L'enceinte de vaporisation comporte un tube de sortie 75 de la vapeur et un tube 77 d'évacuation de l'eau excédentaire lorsque le débit d'eau de circulation est trop important et d'un flasque 79 solidaire de la résistance pour être fixé en 81 à l'enceinte. On a figuré le maillage d'une toile souple baignant en parties supérieure et inférieure dans l'eau à travers des fentes pratiquées dans le tube 69 où l'eau entre en 83 pour ressortir en 85 avant d'être recyclée. Des connexions 87 et 89 permettent par ailleurs l'alimentation de la résistance électrique.In Figures 10 and 11, the porous film is locally immersed in the spraying water which circulates in closed circuit in a pipeline. This kind of device can operate in different positions by the use of a pump and / or a regulating valve intended to ensure a pressurized supply of the water substrate. The spraying means include a rectangular resistor 59 with a power of 270 Watts. On the resistance is applied and tightened a canvas forming a woven film 61 sewn at 63 and 65 to form a sleeve extending downward, housed and integral with the interior of the lower part 67 of the pipe 69. This sleeve also extends inside the upper part 71 of the same pipe 69. The resistance is housed in a 73 spray enclosure. The vaporization enclosure includes a steam outlet tube 75 and a tube 77 for removing excess water when the water flow too much traffic and flaccid 79 integral with the resistance to be fixed in 81 to the enclosure. We figured the mesh of a flexible canvas bathing in upper and lower parts in water at through slits in the tube 69 where the water comes in 83 to come out in 85 before being recycled. Of connections 87 and 89 also allow power electrical resistance.

    Dans ce dispositif, la circulation de l'eau est assurée par une pompe 84 dont on peut régler le débit. La sortie 85 de la canalisation est munie d'un robinet 86. On peut assurer ainsi une légère surpression dans la canalisation pour que le liquide s'écoule préférentiellement dans le film poreux.In this device, the circulation of water is provided by a pump 84 whose flow can be adjusted. The outlet 85 of the pipe is provided with a tap 86. On can thus ensure a slight overpressure in the line for the liquid to flow out preferably in the porous film.

    Par le réglage du robinet, on peut également sursaturer le substrat en liquide, en créant un film d'eau maintenu en surface par la tension interfaciale du liquide sur les faces du film poreux.By adjusting the tap, you can also oversaturate the substrate in liquid, creating a film of water maintained at the surface by the interfacial tension of the liquid on the faces of the porous film.

    Avec la pompe 84 et le robinet 86, on va ainsi disposer de moyens de mise du liquide à une pression supérieure à la pression ambiante dans l'enceinte 73, ceci en amont de la zone où le substrat 61 est exposé à la chaleur de la résistance 59, permettant ainsi d'obtenir les conditions déjà énoncées de débit dans le substrat.With the pump 84 and the tap 86, we go like this have means for putting the liquid at a pressure higher than the ambient pressure in enclosure 73, this upstream of the zone where the substrate 61 is exposed to the resistance 59 heat, thus obtaining the already stated flow conditions in the substrate.

    Le tableau ci-après montre des résultats obtenus avec cette installation à densité de flux constant de 4,7 W/cm2, lorsque l'on fait varier le débit d'eau d'alimentation et que l'on utilise un substrat "à petites mailles" du type déjà présenté. Débit d'eau de circulation g/mn 7 15 22 30 40 50 57 Rendement de vaporisation g/Wh 1,31 1,32 1,30 1,26 1,16 1,12 1,10 The table below shows the results obtained with this installation at a constant flux density of 4.7 W / cm 2 , when the supply water flow rate is varied and a substrate "at small meshes "of the type already presented. Circulating water flow g / min 7 15 22 30 40 50 57 Vaporization yield g / Wh 1.31 1.32 1.30 1.26 1.16 1.12 1.10

    Ainsi, le rendement de vaporisation dans le substrat poreux est de 20 % plus élevé lorsque l'on diminue le débit d'eau entrant de 57 g/mn à 15 g/mn.Thus, the vaporization yield in the porous substrate is 20% higher when decreasing the incoming water flow from 57 g / min to 15 g / min.

    La figure 12 est un exemple de dispositif de goutte à goutte pour alimenter un appareil de vaporisation comparable à celui de la figure 8. Par l'utilisation de toute une gamme de corps poreux interchangeables établissant des débits de liquide constants, on peut alors obtenir une bonne répartition d'écoulement sur de grandes largeurs de substrats et pour de très faible débits. On peut en outre aisément adapter le débit de liquide à la source de vaporisation, voire sursaturer le film poreux. Ce dispositif peut également être utilisé comme piégeage de sels contenus dans de l'eau, ou bien encore comme filtre de liquide interchangeable.Figure 12 is an example of a drip to feed a vaporizer comparable to that of figure 8. By the use of a whole range of interchangeable porous bodies establishing constant liquid flow rates, we can then obtain good flow distribution over large areas substrate widths and for very low flow rates. We can also easily adapt the liquid flow to the source of vaporization, or even oversaturate the porous film. This device can also be used as trapping of salts contained in water, or even as a filter of interchangeable liquid.

    Sur cette figure 12, un double substrat tissé llla, lllb entoure, en pendant, une résistance électrique tubulaire 113, en partie basse d'une enceinte d'évaporation 115. La partie haute du substrat est évasée en "V" et repose sur deux supports. Son alimentation en liquide à évaporer est donc assurée par un goutte à goutte, par l'intermédiaire de deux fins substrats tissés rectangulaires 117, 119, pendant verticalement et se terminant à leur extrémité inférieure libre par des franges 120 favorisant le goutte à goutte et une bonne répartition du liquide.In this figure 12, a double woven substrate llla, lllb surrounds, in pendant, an electrical resistance tubular 113, in the lower part of an evaporation enclosure 115. The upper part of the substrate is flared in a "V" shape and rests on two supports. Its liquid supply to evaporating is therefore ensured by a drip, by through two fine woven substrates rectangular 117, 119, hanging vertically and ending at their free lower end with fringes 120 promoting drip and good distribution some cash.

    En partie haute, les substrats 117, 119 baignent dans un réservoir 121 d'alimentation en liquide, de hauteur de liquide variable, rempli par une alimentation non représentée. Une cheminée 123 permet à la vapeur de s'échapper.In the upper part, the substrates 117, 119 bathe in a liquid supply tank 121, of variable liquid height, filled by a supply not shown. A chimney 123 allows the steam to escape.

    La figure 13 montre un dispositif de vaporisation de liquide utilisant au moins une plaque en acier inoxydable fritté de 1 mm d'épaisseur. Dans cet exemple de réalisation, on vaporise le liquide par le rayonnement thermique d'une résistance électrique.Figure 13 shows a device for vaporization of liquid using at least one plate in 1 mm thick sintered stainless steel. In this example of embodiment, the liquid is vaporized by the thermal radiation from an electrical resistance.

    En l'espèce, deux plaques 125, 127 en "S" d'un alliage fritté en acier inoxydable d'une porosité de 30 % ont été utilisées et disposées dos à dos pour former une voûte en "U" inversé autour de la résistance tubulaire 129. Ces plaques rigides sont accolées en partie supérieure où elles sont maintenues en 131 pour être engagée de manière étanche dans une canalisation 133 où circule le liquide 135 à vaporiser. Par cette disposition et par le fait d'une légère pression dans la canalisation (grâce, par exemple, à une pompe), le liquide va s'écouler dans les volumes vides renfermés par les deux plaques. Au centre de la voûte, et à 10 mm des deux parois, on a localisé la résistance électrique 129 qui s'étend sur toute la longueur de la voûte. En partie basse, on recueille en 137 l'excédent de liquide non vaporisé qui peut être réinjecté à l'entrée du tube 133 pour contribuer à alimenter les substrats.In this case, two plates 125, 127 in "S" of a sintered stainless steel alloy with 30% porosity were used and arranged back to back to form a inverted "U" vault around tubular resistance 129. These rigid plates are joined at the top where they are maintained in 131 to be engaged so watertight in a pipe 133 where the liquid 135 circulates to spray. By this provision and by the fact of a slight pressure in the pipeline (thanks, for example, to a pump), the liquid will flow into the empty volumes enclosed by the two plates. In the center of the vault, and at 10 mm from both walls, we have located the resistance electric 129 which extends over the entire length of the vaulted. In the lower part, we collect in 137 the excess of non-vaporized liquid which can be reinjected at the inlet of the tube 133 to help feed the substrates.

    Si on a immergé localement les parois poreuses 125, 127, le tube réservoir 133, on peut aussi alimenter cet élément de vaporisation par le dispositif de goutte à goutte de la figure 12.If we have locally immersed the porous walls 125, 127, the reservoir tube 133, it is also possible to supply this element of vaporization by the drop device drop of figure 12.

    Le procédé de l'invention et ses exemples de réalisation trouvent leurs applications notamment dans les produits des secteurs de l'artisanat, du grand public, du bricolage ainsi que dans les industries de transformation et de l'agro-alimentaire. Ainsi, en utilisant la combustion du gaz naturel ou l'énergie électrique, on peut créer des générateurs de vapeur allant de quelques kg de vapeur/heure à plus de la tonne/heure. Ces générateurs peuvent être utilisés, par exemple, dans des fours de restauration, de la boulangerie, dans des gazinières grand public, dans l'industrie de la biscuiterie et la pré-cuisson, dans l'industrie du textile pour le traitement des fibres, ou encore, par exemple, pour des centrales vapeur en pressing, voire dans des laboratoires de biologie pour la stérilisation. On peut également réaliser, par exemple, des générateurs de vapeur pour des fers à repasser individuels ou avec centrale vapeur, ou encore, pour des appareils de nettoyage de sols et de murs.The process of the invention and its examples of realization find their applications in particular in products from the craft sector, the general public, DIY as well as in the processing industries and food. So, using combustion natural gas or electrical energy, we can create steam generators ranging from a few kg of steam / hour more than a ton / hour. These generators can be used, for example, in catering ovens, the bakery, in consumer stoves, in the cookie industry and pre-baking, in the textile industry for the treatment of fibers, or again, for example, for steam pressing plants, even in biology laboratories for the sterilization. It is also possible, for example, to steam generators for individual irons or with a steam generator, or even for cleaning of floors and walls.

    Concernant la gamme des densités de flux de chauffage utilisable dans le cadre de l'invention, on notera par ailleurs que l'on peut aller de quelques mW/cm2 à plusieurs dizaines de W/cm2.Regarding the range of heating flux densities usable in the context of the invention, it will also be noted that it can range from a few mW / cm 2 to several tens of W / cm 2 .

    Par ailluers, il doit être clair que le dispositif de l'invention pour fonctionner tant à pression atmosphérique qu'en surpression ou en dépression, seule la mise en pression du liquide devant être prévue pour assurer les conditions de débit rechechées dans le substrat.By the way, it should be clear that the device of the invention to operate both under pressure atmospheric that in overpressure or in depression, only the pressurization of the liquid to be provided to ensure the flow conditions sought in the substrate.

    Claims (16)

    1. Method for evaporating a liquid, in which a porous substrate is supplied with said liquid to be evaporated, and at least one zone of said substrate is exposed to a heat flux, to raise the temperature of at least a part of the surface of the liquid up to its temperature of evaporation, characterized in that a porous substrate is used which is constituted by at least one film which is disposed substantially vertically so that one of its faces is exposed to the heat flux supplied, and that the liquid to be evaporated is supplied to the porous substrate from its upper surface, so that the liquid moves downwardly, evaporating at least from the other face of the substrate.
    2. Method according to Claim 1, characterized in that the thickness of the substrate is included between 0.05 mm and 5 mm.
    3. Method according to Claim 1, characterized in that an additional excess of pressure is created in said column of liquid by a pump.
    4. Method according to any one of Claims 1 to 3, characterized in that the substrate is supplied with liquid at a flowrate slightly greater than the capacity of flow of the liquid within the substrate, so that a small part of this liquid flows over the free surface of said substrate, being maintained thereagainst by interfacial tension.
    5. Method according to any one of the preceding Claims, characterized in that a first end of the substrate is supplied with liquid so that it flows thereover while evaporating and the second end of the substrate is bathed in a bath of the same liquid, and the liquid contained in the bath is used for supplying said first end of the substrate.
    6. Device for evaporating a liquid comprising at least one porous substrate, means for supplying liquid to this substrate, and at least one source of heat energy, for heating at least one zone of the substrate, which is disposed downstream of the supply means, characterized in that:
      the liquid supply means are disposed at a level located above that of the substrate,
      the porous substrate is constituted by at least one essentially vertical film, comprising a face exposed to the heat flux supplied by said source of heat energy and an upper part supplied with liquid to be evaporated under the pressure of the supply means, so that the liquid moves downwardly, evaporating at least from its other face.
    7. Device according to Claim 6, characterized in that the thickness of the substrate is included between 0.05 mm and 5 mm.
    8. Device according to either one of Claims 6 or 7, characterized in that it comprises a plurality of substrates which overlap in part, being spaced apart from one another over at least a part of their surface.
    9. Device according to Claim 8, characterized in that the source of heat energy extends over a certain height, in the form of an exchange wall, and in that three porous films (7a, 7b, 7c) extend respectively over about half of the height of the source of heat energy, three quarters of the remaining part, and a quarter of the uppermost part.
    10. Device according to any one of Claims 6 to 9, characterized in that the substrate is a permeable cloth made of supple fibrous fabric.
    11. Device according to any one of Claims 6 to 10, characterized in that the substrate is a plate of rigid structure, such as metallic and in particularly sintered.
    12. Device according to any one of Claims 6 to 9, characterized in that the substrate comprises yarns of fabric of different diameters.
    13. Device according to any one of Claims 6 to 12, characterized in that the means for supplying liquid to the substrate further comprise drop-by-drop means.
    14. Device according to any one of Claims 6 to 13, characterized in that it comprises at least two substrates having a determined width along at least the essential of which they are supplied with liquid, the two substrates extending on either side of the source of energy, which extends over at least the essential of the width of the substrates.
    15. Device according to any one of Claims 6 to 14, characterized in that:
      said source of energy comprises at least one gas burner,
      and it further comprises two hollow caissons defining therebetween a chimney in which the combustion products of said burner circulate, said caissons each containing at least one substrate.
    16. Device according to any one of Claims 6 to 15, characterized in that the substrate bathes at two of its opposite ends in a tube where said liquid is conducted by forced circulation means, between which the liquid flows.
    EP95918659A 1994-05-18 1995-05-18 Method and device for evaporating a liquid Expired - Lifetime EP0708900B1 (en)

    Applications Claiming Priority (3)

    Application Number Priority Date Filing Date Title
    FR9406076 1994-05-18
    FR9406076A FR2720143B1 (en) 1994-05-18 1994-05-18 Steam generator and associated heating device.
    PCT/FR1995/000656 WO1995031674A1 (en) 1994-05-18 1995-05-18 Evaporation method and heating device therefor

    Publications (2)

    Publication Number Publication Date
    EP0708900A1 EP0708900A1 (en) 1996-05-01
    EP0708900B1 true EP0708900B1 (en) 1998-12-16

    Family

    ID=9463316

    Family Applications (1)

    Application Number Title Priority Date Filing Date
    EP95918659A Expired - Lifetime EP0708900B1 (en) 1994-05-18 1995-05-18 Method and device for evaporating a liquid

    Country Status (9)

    Country Link
    US (1) US5771845A (en)
    EP (1) EP0708900B1 (en)
    JP (1) JPH09500957A (en)
    AT (1) ATE174680T1 (en)
    CA (1) CA2167598A1 (en)
    DE (1) DE69506669T2 (en)
    ES (1) ES2128058T3 (en)
    FR (1) FR2720143B1 (en)
    WO (1) WO1995031674A1 (en)

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    EP2264372A3 (en) * 2009-05-29 2013-02-20 LG ELectronics INC. Ventilation device and controlling method of the same

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    AU2006338580B2 (en) * 2006-02-22 2012-02-16 Texaco Development Corporation Vaporizer and methods relating to same
    US20110147579A1 (en) * 2009-12-18 2011-06-23 First Solar, Inc. Particulate monitoring
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    JP2014518095A (en) 2011-09-06 2014-07-28 ブリティッシュ アメリカン タバコ （インヴェストメンツ） リミテッド Smoking material heating
    RU2606326C2 (en) 2011-09-06 2017-01-10 Бритиш Америкэн Тобэкко (Инвестментс) Лимитед Heating smokable material
    EP3892125A3 (en) 2011-09-06 2022-01-05 Nicoventures Trading Limited Heating smokable material
    RU2595971C2 (en) 2011-09-06 2016-08-27 Бритиш Америкэн Тобэкко (Инвестментс) Лимитед Heating smoking material
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    Also Published As

    Publication number Publication date
    JPH09500957A (en) 1997-01-28
    ATE174680T1 (en) 1999-01-15
    FR2720143B1 (en) 1996-07-12
    DE69506669D1 (en) 1999-01-28
    DE69506669T2 (en) 1999-09-09
    EP0708900A1 (en) 1996-05-01
    ES2128058T3 (en) 1999-05-01
    WO1995031674A1 (en) 1995-11-23
    US5771845A (en) 1998-06-30
    CA2167598A1 (en) 1995-11-23
    FR2720143A1 (en) 1995-11-24

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