EP0488909B1 - Method for controlling the condition of a gas and device therefor - Google Patents

Abstract

Process for regulating the conditioning of a gas stream, in which:   - the temperature of the gas is brought to the desired conditioning temperature,   - the gas is saturated with a so-called conditioning liquid,   - and the saturated and thermally conditioned gas thus obtained is mixed with the said unsaturated unconditioned gas in a proportion which is a function of the desired conditioning. <??>This process consists in saturating the gas in a low-pressure medium at a temperature close to the conditioning temperature of the gas by spraying the conditioning liquid brought to a temperature close to the conditioning temperature of the said gas in the said low-pressure medium. <??>The invention also relates to a device for controlling the conditioning of a gas stream making use of this process. <??>Application: production of air of programmed humidity content. <IMAGE>

Description

The invention relates to a method for regulating the conditioning of a gas. It also relates to a device for conditioning a gas implementing this process; it relates more particularly to an adjustable, controllable regulating device, of the vapor concentration and of the temperature of a gas stream.

• . une amenée de gaz à conditionner,
• . un dispositif saturateur d'évaporation et de mélange,
• . une sortie du courant gazeux conditionné.

As is known, for the most part, a gas conditioning device comprises in a thermostatically controlled enclosure:

• . a gas supply to be conditioned,
• . a saturation device for evaporation and mixing,
• . an outlet from the conditioned gas stream.

In document FR-A-2,558,737, a wet gas generator device has been proposed, in which humidified air is mixed with dry air in order to produce a reference wet gas, in particular for monitoring and the calibration of a hygrometer in industrial operation, particularly suitable for regulation in the steel industry. According to this document, the thermostatically controlled humidifier is constituted by a bubbling chamber partially filled with water at constant level, connected on the one hand by a diffuser to the inlet of gas to be humidified, on the other hand, to a tubing d water supply at constant level, and finally to an outlet for the humidified gas. This solution is perfectly suited to low flow rates, especially for calibrating a probe or a hygrometer. However, because of the very bubbling technique, this device cannot be used for packaging large volumes, such as parts, workshops or spraying devices, which require substantial flow rates, since such flow rates are not not compatible with a bubbling humidification system.

Furthermore, there is an increasing interest in producing air conditioning, the moisture content of which is controlled to within 1%, or even one per thousand. This is particularly the case for measuring devices.

One of the objects of the invention is to propose a process capable of allowing the humidification or saturation of a gas to be carried out, and generally the conditioning of a gas, for relatively large volumes, by optimizing the saturation process of said gas.

A first aspect of the invention is therefore a method for regulating the conditioning of a gas stream according to claim 1.

In other words, the invention consists in saturating the gas already thermally conditioned with the conditioning liquid also thermally conditioned, and this in a low pressure medium, thereby promoting the evaporation process, and optimizing the saturation phenomenon.

Advantageously, the saturation of the gas is self-regulated by the depression itself generated in the low pressure environment.

The device according to the invention makes it possible to obtain these results economically and efficiently.

• . une amenée de gaz à une température programmée, reliée à une source dudit gaz ;
• . un saturateur de gaz pour amener un liquide de conditionnement au contact du gaz à conditionner ;
• . une tubulure de sortie de gaz conditionné reliant l'orifice de sortie du saturateur au volume à conditionner.

This regulating device for conditioning a gas stream, comprises in a thermostated enclosure, intended to receive a heat transfer liquid, and immersed in this enclosure:

• . a gas supply at a programmed temperature, connected to a source of said gas;
• . a gas saturator for bringing a conditioning liquid into contact with the gas to be conditioned;
• . a conditioned gas outlet pipe connecting the outlet port of the saturator to the volume to be conditioned.

• . un convergent relié à la tubulure d'amenée thermostatée, prolongeant l'amenée dudit gaz,
• . un col,
• . un divergent débouchant dans la chambre de vaporisation,

ladite chambre de vaporisation présentant :

• . une tubulure reliant le liquide de conditionnement et débouchant dans le col du venturi,
• . et un orifice de sortie disposé au-dessus du niveau maximum prévu pour le liquide de conditionnement dans la dite chambre de vaporisation.

According to the invention, the saturator is constituted by a pressure-reducing duct with a "venturi" effect associated with a vaporization chamber, comprising means for supplying liquid with a constant level of condi, the venturi duct comprising in order:

• . a convergent connected to the thermostatically controlled supply pipe, extending the supply of said gas,
• . a collar,
• . a divergent opening into the vaporization chamber,

said vaporization chamber having:

• . a tube connecting the packaging liquid and opening into the neck of the venturi,
• . and an outlet orifice disposed above the maximum level provided for the conditioning liquid in said vaporization chamber.

In other words, the conditioning liquid conveyed at the neck of the venturi duct by the depression created at its level, is sprayed into the gas stream already thermally conditioned, this spraying in a low pressure medium also taking place at the temperature gas conditioning system, the saturator being immersed in the thermostatically controlled enclosure. In this way, the evaporation process is favored, since following its passage through the venturi neck, where the gas flow speed and consequently the depression created at this level are the most important, the gas certainly undergoes a decrease in its temperature, but this decrease is immediately compensated for by the supply of heat by convection due to the flow of gas along the conditioned walls of the divergent. This evaporation is further accentuated by the choice of a diverging angle with a small apex, therefore of relatively large length, so that the gas flow speed is not immediately reduced, thereby maintaining a certain depression. In other words, the walls of the divergent compensate for the evaporation due to the adiabatic exchange. In addition, taking into account the particular structure of the device, the conditioning can result in both heating and cooling of the volume, since the operating system is reversible.

Advantageously, the vaporization chamber comprises a liquid-gas separation chamber situated above the level of the conditioning liquid, and connected to the outlet pipe.

In a practical embodiment, the gas stream is compressed air, and the humidifying liquid is water.

In a preferred embodiment, to obtain conditioned air with controlled and programmed humidity, the dry air supply pipe is connected by a connection disposed outside of the thermostatically controlled enclosure to a controlled mixing valve, connected to the outlet tubing of the vaporization chamber, said mixing valve being in turn connected to the outlet tubing which passes through the thermostatically controlled enclosure.

• le gaz comprimé est de l'air comprimé sec dont la source est reliée en série à la tubulure d'amenée par un premier détendeur, puis, par un moyen dessicant, par un second détendeur associé à une vanne, pour introduire dans la tubulure d'amenée de l'air sec comprimé à débit constant ;
• de manière connue, le liquide de transfert thermique (avantageusement de l'eau) de l'enceinte thermostatée, comprend une résistance électrique, un agitateur, un thermomètre et un moyen d'affichage et de programmation de la température de l'eau et de l'enceinte, le tout étant pilotable depuis l'extérieur ;
• le moyen d'alimentation en eau de la chambre de vaporisation à niveau constant, comprend hors de l'enceinte thermostatée, en série, un vase d'expansion, une première vanne autorisant une légère fuite d'air, une réserve d'eau thermostatée par l'eau de l'enceinte, une seconde vanne pilotée, et une tubulure traversant l'enceinte thermostatée, reliée à un orifice débouchant dans la chambre de vaporisation, pour maintenir dans celle-ci un niveau constant ;
• la tubulure de sortie présente en série une vanne mélangeuse pilotable, reliée à un serpentin disposé dans l'enceinte thermostatée ;
• cette vanne mélangeuse est associée à une vanne légèrement ouverte, autorisant une légère fuite destinée à assurer dans tous les cas un débit minimum d'air dans le saturateur ;
• la chambre de vaporisation à niveau constant comporte une succession de plaques ou de grilles parallèles horizontales réalisées en un matériau conducteur thermique, lesdites grilles ou plaques faisant alors corps avec la chambre de vaporisation, et comportant une pluralité d'orifices décalés d'une plaque ou d'une grille par rapport à l'autre ;
• l'humidificateur étanche immergé dans l'enceinte, est réalisé en un matériau conducteur de la chaleur, et comporte des ailettes d'échange thermique avec le liquide de transfert thermostaté ;
• la tubulure reliant la chambre de vaporisation et débouchant dans le col du venturi, présente des orifices opposés disposés horizontalement dans la section du col ;
• l'orifice de sortie de la chambre de vaporisation est relié par un séparateur de gouttelettes de type centrifuge disposé dans l'enceinte au dessus dudit orifice, et dont la sortie de gaz saturé est reliée à la tubulure, le liquide séparé retournant ensuite par une autre tubulure dans le liquide de conditionnement par l'orifice situé au dessous du niveau constant.

Advantageously, in practice:

• the compressed gas is dry compressed air, the source of which is connected in series to the supply manifold by a first expander, then, by desiccant means, by a second expander associated with a valve, to introduce into the manifold d '' supply of compressed dry air at constant flow;
• in known manner, the heat transfer liquid (advantageously water) from the thermostatically controlled enclosure, comprises an electrical resistance, an agitator, a thermometer and a means of displaying and programming the temperature of the water and of the enclosure, the whole being controllable from the outside;
• the means for supplying water to the constant-level vaporization chamber, includes, outside the thermostatically controlled enclosure, in series, an expansion vessel, a first valve allowing a slight leakage of air, a water reserve thermostatically controlled by the enclosure water, a second piloted valve, and a tube passing through the thermostatically-controlled enclosure, connected to an orifice opening into the vaporization chamber, in order to maintain a constant level therein;
• the outlet manifold has in series a controllable mixing valve, connected to a coil disposed in the thermostatically controlled enclosure;
• this mixing valve is associated with a slightly open valve, allowing a slight leak intended in all cases to ensure a minimum air flow in the saturator;
• the constant-level vaporization chamber comprises a succession of horizontal parallel plates or grids made of a thermal conductive material, said grids or plates then forming one body with the vaporization chamber, and comprising a plurality of orifices offset by a plate or one grid with respect to the other;
• the waterproof humidifier immersed in the enclosure, is made of a heat conductive material, and has fins for heat exchange with the thermostatically controlled transfer liquid;
• the tubing connecting the vaporization chamber and opening into the neck of the venturi, has opposite orifices arranged horizontally in the section of the neck;
• the outlet of the vaporization chamber is connected by a centrifugal type droplet separator placed in the enclosure above said orifice, and the outlet of saturated gas of which is connected to the tubing, the separated liquid then returning via a other tubing in the conditioning liquid through the orifice located below the constant level.

The manner in which the invention can be implemented and the advantages which result therefrom will emerge more clearly from the embodiment which follows, supported by the appended figures.

Figure 1 is a schematic representation of a preferred device of the invention.

Figure 2 is a sectional representation of the sealed assembly characteristic of the invention.

Figure 3 is a schematic representation of a simplified embodiment of the invention.

FIG. 4 shows an execution detail suitable for embodiments requiring high flow rates.

The device according to the invention for producing conditioned air with controlled and programmed humidity, firstly comprises a source of air, for example compressed air (1) such as a compressor, a bottle, etc., connected by tubing to a valve (2), then to a pressure regulator (3). This regulator (3) is in turn connected to a known hygroscopic desiccator assembly (4), for example of the type called "VAN AIR" marketed by AUXITROL which, in known manner, has a drain (5). This desiccant assembly (4) is in turn connected to a second pressure reducer (6), then to a pressure gauge (7) and to a valve (8), so as to ensure a constant flow of dry air in the manifold. supply (21) (dry compressed air pressure on the valve (8) between six hundred and one thousand KPa).

The actual packaging device designated by the general reference (10) comprises a thermostatically controlled enclosure, advantageously insulated, filled with distilled water (12) to a level (13). This enclosure (11) is thermostatically controlled by known means (14) essentially comprising, immersed in water, an electrical resistance (15), an agitator (16) associated with a circulation pump, a thermometer (17) and an apparatus (18) temperature programming display and control, the assembly being controllable from the outside.

The dry compressed air opens into the enclosure (11) through an orifice (20), then is connected to a supply pipe (21) forming a coil (22) immersed in this enclosure. This tubing (21) and the coil (22) are connected by a T-shaped connection (23) to two other tubings, respectively a submerged tubing (24), and another non-fully submerged tubing (25), leaving the enclosure. (11). The submerged tubing (24) is connected to the humidifier (30) characteristic of the invention.

This characteristic waterproof humidifier (30) detailed in FIG. 2, essentially comprises a pressure-reducing or pressure-reducing conduit with a venturi effect associated with a vaporization chamber (36). The venturi tube is constituted in order by a convergent (31) connected upstream (32) to the dry air supply pipe (24) immersed, then downstream to a neck (33). This neck (33) is associated with a divergent (34) in turn connected by a conical connection (35) to the characteristic cylindrical vaporization chamber (36). In a practical embodiment, for a venturi duct of axial symmetry, the angle at the top of the convergent (31) is close to 21 °, while the angle at the top of the divergent (34) is close to 6 or 7 ° .

The characteristic vaporization chamber (36) has at the bottom (37) an orifice (38) connected by a tube (39) immersed in the enclosure (11) to a water supply means designated by the general reference ( 40) disposed outside of this enclosure (11). This water supply means (40) is thermostatically controlled by a serpentine tube (41), drawing water (12) from the thermostatically controlled enclosure (11). This water supply means (40) disposed outside the enclosure, essentially comprises in order an expansion tank and water supply distilled (42), connected to a manual valve (43), then to a tank proper (44), opening onto a valve (45) electro-pneumatically controlled, connected to the immersed tubing (39). The valve (43) is slightly open so as to ensure a certain flow rate of air leakage and therefore maintaining the water (50) in the vaporization chamber (36) at a constant level (51), defined by l orifice (38).

According to another characteristic of the invention, the distilled water (50) of the vaporization chamber (36) is connected by a tube (52), first of all to a dust filter (56) intended in particular to avoid the clogging, then to the nozzle arranged in the neck (33) of the venturi. The bottom (53) of this tubing (52) is disposed below the level (51), so that the neck (33) is permanently supplied with distilled water. The upper end (54) of the tubing (52) opens exactly into this neck (33) which, for this purpose, has two opposite through holes (55), arranged horizontally opposite one another in the section even of the neck (33) thus forming a nozzle.

In known manner, the venturi induces a depression at the level of the diverging portion (34), which causes the water (50) to be drawn in at the neck (33) and its instantaneous spraying in the form of fine droplets in the diverging portion (34 ), some of which fall back into the chamber (36).

Advantageously, the characteristic humidifier (30) is machined in bronze, and is therefore a thermal conductor. In addition, it comprises fins (60, 61) intended to facilitate heat exchange with the thermostatically controlled transfer liquid (12). In this way, the temperature of the diverging portion (34) and of the vaporization chamber (36) is very close to the temperature of the thermostatically controlled liquid.

In a practical embodiment, the vaporization chamber (36) has two horizontal plates (not shown), pierced with through orifices offset from one plate to the other, or two appropriate grids, in order to cause the deposit on these plates or on these grids drops of water carried by saturated air. In addition, it is advantageously possible to insert between the two grids sintered metal in the form of shot, or even "PORAL" (registered trademark). These plates or grids are advantageously made of a thermal conductive material, thus making it possible to complete the condensation or evaporation of the liquid as the case may be, by increasing the heat exchange surface. In addition, these grids play a regulating role, insofar as when water droplets are deposited at the level of said grids, thereby reducing the air flow passing through the grids, they in fact reduce the pressure difference between the neck (33) of the venturi and the vaporization chamber. In this way, the quantity of distilled water drawn in at the level of the neck (33) is reduced, and consequently, the spraying decreases. In fact, a smaller amount of droplets is deposited at the grids, increasing the pressure difference, and therefore the amount of water sprayed at the neck (33). One thus obtains a self-regulation of the saturation, and a permanent mode compared to the imposed set point.

According to another characteristic of the invention, the vaporization chamber (36) has, above the constant level of the water (51), an outlet orifice (65), through which the almost saturated air will escape in steam. This outlet port (65) for saturated air is placed just above an annular chamber (66), then is connected by a tube (67) immersed in a controlled mixing valve (70), for example arranged outside of the enclosure (11), and is also connected to the non-submerged dry air supply pipe (25). If it is desired to work at high temperature, it is preferable then that the mixing valve (70) is also immersed in the enclosure (11).

For large flows in the saturator (30) (see FIG. 4), a centrifugal-type droplet separator (100), placed in the enclosure (11), is placed between the orifice (65) and the tubing (67). above the orifice (65), and the outlet (101) of saturated gas of which is connected to the tube (80). The separated liquid then returns through the tubing (102) into the liquid (50) through the orifice (103) located below the constant level (51).

The mixing valve (70) is advantageously associated with another valve (71), intended to maintain a slight leak to ensure the ascent of the water in the tubing (52). The mixing valve (70) is then connected by a tubing (72) to a submerged coil (73), which is connected by a new tubing (74) to the volume (75) to be conditioned disposed outside the enclosure (11).

The gas conditioning device according to the invention operates in the following manner.

The compressed air (1) is brought to temperature by passing through the thermostatically controlled enclosure (11). Its forced passage through the venturi (31,33,34) causes the water (50) contained in the vaporization chamber (36) to be sucked in via the pipe (52) and its filter (56). The water which then opens into the neck (33) of this venturi saturates the air which passes through it. This air, after having discharged the heaviest drops of water on the horizontal plates of the vaporization chamber (36), leaves the latter through the orifice (65) and the pipe (67) until reaching the mixing valve (70). This valve (70) is controlled so that the air which escapes therefrom at (72) has a determined hygrometry. Indeed, for a precise position of this valve (70), corresponds to a stable air humidity. If you want to control the operation more precisely, you can measure the temperature and humidity in the volume to be conditioned (75) and keep the setpoint at 0.1% relative humidity by small pulses on this valve (70).

• un appareil de mesure de la température et de concentration en vapeur de gaz conditionné (75) ;
• un système à microprocesseur équipé d'une carte multifonctions entrées/sorties, numériques/analogiques, et un logiciel spécifique de contrôle et de pilotage des éléments pilotables, tels que (2,6,8,14,45,70), gérant les consignes programmées de température et de concentration en vapeur.

In an embodiment not shown, the automated packaging device according to the invention further comprises:

• an apparatus for measuring the temperature and vapor concentration of conditioned gas (75);
• a microprocessor system equipped with a multifunction input / output, digital / analog card, and specific software for controlling and controlling the controllable elements, such as (2,6,8,14,45,70), managing the setpoints temperature and steam concentration.

The water sprayed into the neck (33) is partly evaporated in the diverging portion (34) and the chamber (36), and the excess falls back into the tank (37). The heat required for this evaporation is provided by the conductive body of the humidifier (30) provided with exchange fins (60, 61). As already said, the separation of the droplets and additional evaporation is obtained by passage through baffles (plates, grids) located in the chamber (36). Given the structure of the humidifier, we observe a maximum heat input at the beginning of the divergent, and therefore from the start of the droplets in it, due to the strong depression which reigns in this place. This contribution decreases with the widening of the divergent (34), and therefore corollary with the rise in pressure. This heat exchange is further optimized by the adoption of a divergent tapered profile (6 ° angle at the top). In this way, uniform heating of the assembly is obtained, and a constant supply of heat for a given flow rate.

The saturated air produced (67) is then mixed with dry air (25) in a controllable mixing valve (70) to produce the conditioned air (75). If a slight air leak in (43) allows a sweep and the maintenance of the constant water level (51) in the chamber (36), another controlled leak (71) also makes it possible to maintain a slight flow necessary for the spray when relatively dry air is desired. Indeed, this controlled leak (71) allows the ejection of saturated air, and correspondingly prevents defusing the venturi. Finally, it makes it possible to use this device even for very low flow, since the pressure drop is permanently maintained.

The air contained in the chamber (36) exerts a pressure greater than the column of water contained respectively in the tubing (39) and in the tank (44). As the valve (43) allows a slight flow of air leakage, a reverse water-air flow is established in the duct (39), so that if the water level (51) in the vaporization chamber (36) exceeds that of the high point of the orifice (38), the excess water is discharged into the tank (44). On the other hand, when the water level (51) in the chamber (36) is below the high point of the orifice (38), the water descends from the reservoir (44) towards the chamber (36). Thus, the water level in the vaporization chamber (36) is regulated by excess or by fault, the regulation precision being fixed by the leakage air flow authorized by the valve (46). The reservoir (44) can be filled in a complementary manner from the expansion tank (42), after the closing of the piloted valve (45) and the opening of the valves (43) and (46).

Figure 3 shows as already said a simplified embodiment of the invention. The parts common to Figures 1,2 and 3 have kept the same references.

In this embodiment, the pressurized air (1) is expanded to a set pressure by passing it through a controlled pressure regulator (6) before the inlet (20) of the thermostatically controlled enclosure (11). The dry air supply tubing (24) is integrally connected to the sealed humidifier (30), and the saturated air outlet port (65) is integrally connected to a tubing (80,67) associated in series to a pressure reducer (81), then to a pressure gauge (82) and a valve (83), and always in series to the submerged coil (73) in turn connected to the volume (75) to be conditioned. Alternatively, the regulator (81) / valve (83) assembly can be replaced by a flow regulator. In this way, by simply varying the flow rate, it is possible to obtain the desired conditioning of the volume (75) of gas of constant concentration in water vapor, directly a function of the pressure and the temperature prevailing in the humidifier (30). .

In this embodiment, the operation of the installation is particularly stabilized at constant air flow. Variations in the humidity of the outlet air (75) are directly linked to the pressure and temperature in the humidifier (30), and to the temperature and working pressure. This completely reversible form of use can also be used to dehumidify the air for room conditioning, for example, or can be used for compressed gases other than air, and liquids other than water. This solution is particularly advantageous, because it leads to controlled air which can be calculated from known physical laws, since everything passes through the venturi (33). However whatever the humidity required, the flow rate is always constant in the vaporization chamber (36).

• une bonne compacité et un faible encombrement ;
• la possibilité d'obtenir de grands débits conditionnés de manière efficace, ce que ne permettait pas les solutions décrites dans le préambule ;
• un fonctionnement autonome ;
• une souplesse de fonctionnement ;
• une possibilité de programmation et de gestion du conditionnement par micro-ordinateur ou automate programmable ;
• une efficacité accrue, de par l'utilisation d'un humidificateur particulièrement performant.

The device according to the invention has many advantages compared to those known and marketed to date. We can cite :

• good compactness and compactness;
• the possibility of obtaining large conditioned flows efficiently, which the solutions described in the preamble did not allow;
• autonomous operation;
• flexibility of operation;
• a possibility of programming and management of packaging by microcomputer or programmable controller;
• increased efficiency, through the use of a particularly efficient humidifier.

In this way, this device can be used successfully for the conditioning of any volume or any enclosure requiring a hygrometric degree controlled and programmed with precision, such as for example in measuring devices, in particular in laboratories, or in spray guns. spraying, for example of paint, gas and solvent mixtures, etc.

Claims (13)

1. Method for regulating thg conditioning of a gaseous flow, in which :

   - the temperature of the gas is brought to the desired conditioning temperature,

   - the gas is saturated by means of a liquid called conditioning liquid,

   - and the saturated and thermally conditioned gas thus obtained is mixed with the said non-saturated non-conditioned gas in a proportion depending on the desired conditioning,

   characterised in that it consists :

   - in bringing the liquid temperature to a temperature in the vicinity of the temperature for conditioning the gas ;

   - in sauurating the gas by pulverisation of said liquid in a pipe generating a partial vacuum by Venturi effect itself thermally conditioned, and comprising in order :

   . a converging region connected to a compressed gas inlet tubing ;

   . a neck, at the level of which the conditioning liquid emerges ;

   . a diverging region emerging in a vaporisation chamber delivering the saturated and conditioned gas.
2. Method according to claim 1, characterised in that the saturation of the gas is self-regulated by the reduced pressure itself generated in the reduced-pressure environment.
3. Method according to one of claims 1 and 2, characterised in that the gas is previously pressure-regulated at the input by a controllable means and is integrally introduced into the converging region of the Venturi, and in that the saturated gas coming from the vaporisation chamber has a pressure which is reduced at a constant rate to the pressure of use, so as to obtain a conditioning of the gas to a constant concentration of vapour of the cooling liquid and directly depending on the temperature and pressure in the humidifier.
4. Method according to one of claims 1 to 3, characterised in that the gas to be conditioned is compressed air and in that the conditioning liquid is water.
5. Regulating device for conditioning a gaseous flow, comprising in a thermostatted enclosure (11) intended to receive a heat transfer liquid (12), immersed in this enclosure (11) :

   - an inlet (21, 22) of gas at a programmed temperature, connected to a source (1) of gas ;

   - a gas humidifier (30) for bringing a conditioning liquid (50) into contact with the gas (1) to be conditioned ;

   - a conditioned gas outlet tubing (67, 72, 73, 74, 80) connecting the outlet orifice of the humidifier to the volume (75) to be conditioned,

   characterised in that the humidifier (30) is formed by a pipe generating a partial vacuum by Venturi effect, associated with a liquid constant level vaporisation chamber (36) comprising liquid supplying means, the Venturi pipe comprising, in order :

   - a converging region (31) connegted (32) to the thermostatted inlet tubing (24), extending the inlet (20, 21) of said compressed gas ;

   - a neck (33),

   - a diverging region (34) emerging in the vaporisation chamber (36),

   said vaporisation chamber (36) having :

   . a tubing (52) connecting the conditioning liquid (50) and emerging in the neck (33) of the Venturi,

   . and an outlet orifice (65) disposed above the maximum specified level of the conditioning liquid (50) in said vaporisation chamber (36).
6. Regulating device for conditioning a gaseous flow according to claim 5, characterised in that the vaporisation chamber (36) comprises a liquid-gas separation chamber (66) itself located above the specified level (51) of the liquid (50) and connected to the outlet tubing (67, 72, 73, 74, 80).
7. Conditioning device according to one of claims 5 and 6,! characterised in that the vaporisatioo chamber (36) has a means (40) for supplying liquid to a constant level (51), formed by an expansion vessel (42), a first valve (43) allowing a slight leakage, a thermostatted liquid reservoir (44) and a controlled second valve (45), this thermostatted assembly eisposed outside or inside the enclosure (11) being connected via a tubing (39) which traverses the enclosure (11) and is connected to an orifice (38) emerging in the vaporisation chamber (36) having a constant level (51).
8. Conditioning device according to one of claims 5 to 7, characterised in that the end of the tubing (52) connecting, by means of a filter (56), the vaporisation chamber (36) to the neck (33) of the Venturi, comprises two traversing orifices (55) facing each other horizontally in the cross-section of the neck (33).
9. Conditioning device according to one of claims 5 to 8, characterised in that the vaporisation chamber (36) having a constant level (51) comprises a succession of horizontal plates or grids made from a thermally conductive material, and integral with said chamber, the grids or plates comprising a plurality of orifices offset from one plate in relation to another, which are intended to stop the condensation droplets of the conditioning liquid and, hence, to promote the heat exchange between the saturated gas and the vaporisation chamber.
10. Conditioning device according to one of claims 5 to 9, characterised in that the outlet orifice (65) of the vaporisation chamber (36) is connected via a centrifuge-type droplet separator (100) disposed in the enclosure (11) above said outlet orifice (65) and whose saturated gas outlet (101) is connected to the outlet tubing (80), the outlet of the separated liquid being connected by a tubing (102) to the liquid reserve (50) via an orifice (103) situated below the constant specified level (51) of the liquid.
11. Conditioning device according to any one of claims 5 to 10, characterised in that the dry gas inlet tubing (22) is connected via a branch-off (23) to a second tubing (25) connected via a controlled mixer valve (70) to the saturated gas outlet tubing (67) of the vaporisation chamber (36), said mixer valve (70) being connected in series, in turn, to a thermostatted tubing (73) connected to the outlet tubing (74).
12. Conditioning device according to claims 5 to 11, characterised in that the source of compressed air (1) is connected to the inlet tubing (21) in series via a pressure-reducing valve (3), a drying means (4) and a second pressure-reducing valve (6) in order to bring into the tubing (21) dry air at a constant rate.
13. Conditioning device according to claim 11, automated, comprising :

    - an apparatus for measuring the temperature and vapour concentration of conditioned gas (75) ;

    - a microprocessor system equipped with a digital/ analog, input/output multifunctional card ;

    - specific software for monitoring and controlling the controllable elements (2, 6, 8, 14, 45, 70) managing the programmed temperature and vapour concentration reference values.

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