FR2832771A1 - Creation of a slow flow of rising fluid to fuel colored flames, uses a narrow vertical tube to deliver fluid and injects bubbles into base of tube to carry fluid up, with rate of injection of bubbles controlling rate of delivery of fluid - Google Patents

Abstract

The slow delivery of liquid at the top of a vertical tube (4) of small transverse section uses admission of a succession of gas bubbles into a bubble chamber (3) at the bottom of the vertical tube. The gas bubbles (13,17) have a section at least equal to the transverse section of the vertical tube and rise up the tube. The gas or liquid can contain a chemical to produce a colored flame.

Description

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 The present invention relates to a simple and inexpensive method and device for an upward supply of liquid. It is particularly suitable for a regular low flow supply, usable in all cases where a supply pressure is not required; this is the case with lubrication, addition of chemical reagents, release of perfumes into the ambient air, production of bubbles such as soap bubbles and lamps with combustible liquid, without limitation.

 In a preferred embodiment, the method and the device of the invention are used to produce a flame lamp and more particularly a colored flame lamp.

 Devices for supplying small regular flow rates of liquids of the order of, for example, a few tens of milliliters per hour usually require the availability of small parts, static or mobile, of appreciable cost due to the precision required. In addition, these parts may become blocked by the presence of impurities.

 The method and the device of the invention do not have the above drawbacks and are characterized by great simplicity and low cost. They allow in particular to raise a liquid from a lower level to a higher level, without applying pressure to this liquid, the liquid rising under the sole action of gas bubbles.

 The invention relates firstly to a method for producing a low liquid flow rate at the upper end of an ascending tube of small internal cross section from a reserve of the liquid whose level is maintained at the same time lower to that of the upper end of said ascending tube and higher than that of the lower end of this same tube, characterized in that: a) the liquid reserve is placed in communication with a chamber, called bubbling chamber, communicating by elsewhere, on the one hand, at its upper part, with the lower end of said ascending tube and, on the other hand, with a gas source via a gas inlet orifice which is located at a level of the bubbling chamber lower than the level of the lower end of the riser, the section of the gas inlet orifice in the bubbling chamber being sufficient to produce in the liquid of the bubbling chamber successive gas bubbles whose cross section is at least equal to the cross section

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 internal of the ascending tube, the communication of the reserve liquid with the bubbling chamber taking place away from the path of said gas bubbles, and b) while maintaining the reserve liquid level as indicated above , the gas is admitted into the bubbling chamber by passing through the gas inlet orifice at a rate sufficient to produce a succession of bubbles in the liquid, said flow being however less than that which would lead to an accumulation of bubbles of gas in the top of the bubbling chamber, so as to let rise in the ascending tube said succession of gas bubbles separated by portions of entrained liquid and to release said portions of liquid at the upper end of said ascending tube.

 The invention also relates to a device comprising an ascending tube communicating by its lower end with the upper end of a chamber called bubbling chamber, said bubbling chamber being moreover in communication on the one hand with a reservoir for liquid and secondly with a gas source, said reservoir being capable of containing said liquid at a level both higher than the level of the lower end of the riser and lower than the level of the upper end of said riser, the communication between the bubbling chamber and the gas source via a gas inlet orifice located at a level of the bubbling chamber below the level of communication of said chamber with the lower end of the ascending tube and the communication between the bubbling chamber and the liquid reservoir takes place via at least one liquid admission orifice s ituted away from the upward path followed by gas bubbles which can form when the bubbling chamber is filled with liquid and the gas is admitted into said chamber, said device further comprising means for controlling the flow of gas allowing it to be admitted into the bubbling chamber in the form of a train of successive gas bubbles, the cross section of which is at least equal to the internal cross section of the ascending tube.

 It will be readily understood that the gas bubbles can deform when they enter the ascending tube and that they can take a different shape, in particular elongated in the direction of their ascent. However, they remain separated from each other by drawing portions of the liquid between them.

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 According to a preferred embodiment of the invention, the cross section of the bubbling chamber is greater than both the maximum internal cross section of the riser and the cross section of the gas inlet orifice in the chamber bubbling.

 The dosage between liquid and gas flow rates is carried out in the bubbling chamber located at the base of the ascending tube and provided with the following three orifices: - a gas supply orifice, the section of which determines the size of the bubbles formed, - a liquid inlet orifice ensuring the admission of the latter from its reservoir. The geometry of this second orifice is not critical, provided that it is not located at the top of the chamber to prevent the bubbles of gas formed from entering it. This risk can be further reduced by the narrowing of this second orifice or by its positioning at a level lower than the level of arrival of the gas in the bubbling chamber.

 - An orifice for the exit of the bubble train at the upper end of the bubbling chamber, said orifice being constituted by the lower end of the ascending tube. This orifice is preferably arranged above the gas supply nozzle. This third orifice is advantageously preceded by an inverted funnel access to facilitate the collection of bubbles and to avoid their division.

 The gas flow rate is preferably substantially greater than the flow rate of liquid to be supplied with a volumetric base, for example 5 to 20 times greater.

 It is considered that the gas is bubbled through the liquid to be supplied, forming bubbles whose cross section (horizontal) is at least equal and preferably greater than the maximum internal section of the riser. This is achieved by adjusting the gas inlet port. This orifice can have a cross section greater than, equal to or even slightly less than that of the ascending tube because the bubbles tend to increase in cross section and in volume at the outlet from the gas inlet orifice. The section of this orifice can advantageously represent 75 to 200% of the maximum internal section of the ascending tube, subject to compliance with the condition of size of the bubbles formed. This size of the bubbles formed is to a certain extent a function of the nature of the liquid, its density and its viscosity. It is believed that a viscous liquid will promote the magnification of bubbles at the outlet of the gas inlet nozzle.

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 The concept of "maximum internal section" of the ascending tube refers to the case of a tube whose internal section is not constant at all levels. In the more common case of a tube of constant internal section, the maximum internal section is equal to the internal (constant) section of the tube.

 The carrier gas flow rate is chosen as a function of the flow rate desired for the upward supply of liquid. It is however limited as a function of the assembly and in particular of the section and the length of the riser tube. Thus, in this tube, each gas bubble is separated from the previous one and the next one by a small amount of liquid which is entrained at the top of the tube. Excessive gas flow could cause gas to build up in the upper part of the bubble chamber and the liquid would then no longer be entrained in the riser.

 As the level of the top of the riser is located above the level of charge of the liquid located in the supply tank, the liquid is entrained higher than this level of the tank by the effect of the train of gas bubbles. Consequently, stopping the gas supply causes the liquid outlet to stop.

 According to a preferred embodiment of the invention, the cross section of the riser is, in all respects, less than 1 square centimeter, and preferably less than 10 square millimeters, so as to ensure that the liquid pushed upwards by the train of bubbles slides as little as possible between these bubbles and the wall of the riser. To obtain an even lower liquid flow rate, said section can be from 1 to 5 square millimeters or even lower.

 According to another embodiment, at least the upper part of the bubble chamber has the shape of a funnel widening downwards.

 According to another embodiment, the source of gas bubbles in the bubbling chamber is constituted by a single opening so as to create a single column of successive gas bubbles in the liquid.

 According to another embodiment, the device comprises a burner at the upper end of the rising tube, intended for the combustion of the liquid and / or the gas when at least one of them is combustible.

 The burner can be constituted simply by the upper end of the rising tube. It can also be an incombustible or hardly combustible porous body capable of being impregnated with the liquid collected at the top of the ascending tube. The porous body can be, for example, sintered metal, porcelain

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 porous, porous concrete, sintered porcelain or even be made of a wick similar to that of an oil lamp.

 The burner may also include a wire mesh or a packed wire sleeve.

 In another embodiment, the gas of the mixture of gas bubbles and liquid is burnt at the upper end of the riser tube in contact or mixture with an auxiliary flame originating, for example, from a conventional gas burner.

 The method and the device can also be used to produce a colored flame lamp.

 The method and the device are then defined as indicated above except that: a) the liquid contains at least one compound capable of coloring a flame; they are generally compounds of certain metals; b) the gas is combustible, and c) igniting and allowing the mixture of liquid and gas obtained to burn at the top of the rising tube, possibly in contact with the flame of an auxiliary burner.

 For use with a flame (lamp), the gas is preferably combustible, for example methane, ethane, propane, butane or isobutane, and the liquid is preferably combustible. The liquid can even be aqueous if its proportion is small compared to that of the combustible gas; it then serves only as a solvent for the compounds intended to color the flame.

 If the gas is inert (nitrogen, argon, for example) the liquid must be combustible to use it in a flame lamp. The gas can also be air provided that it cannot form an explosive mixture with the liquid or its vapor inside the device of the invention.

 For safety reasons, a liquid with a high flash point is preferred, for example greater than 50 ° C. and preferably greater than 80 ° C.

 For the coloring of the flame, a finely suspended compound, or preferably dissolved, is used in the liquid, one of the constituent elements of which is chosen for the coloring of the flames which it provides. These compounds are well known to those skilled in the art. As examples, mention may be made of: lithium: red, sodium: yellow,

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 copper in halogenated compositions: green or blue, borates: green, carbon: yellow or white.

 These emitting compounds can be mineral, for example nitrate or chloride, in particular if the liquid is aqueous or aqueous alcoholic or aqueous glycolic, or organic, for example acetate, hexanoate, ethylhexanoate, stearate, oleate, acetylacetonate, if the liquid is organic (hydrocarbons , alcohol, glycol, amide, for example). We prefer liquids whose combustion takes place without significant carbon.

 As can be seen, an advantage of the invention is that the device described does not require any moving mechanical part. Another advantage lies in the fact that the flow of liquid produced by the train of bubbles depends little on the level of liquid in the tank under load; the difference in level between the liquid in the reservoir and the top of the riser is preferably between 5 and 20 centimeters, although much higher level differences are possible.

 The unit quantity of liquid supplied to the top of the ascending tube can be adjusted according to the invention by adjusting the size of the bubbles in relation to the section of the ascending tube.

 The quantity of gas required to ensure a regular flow is generally of the order of 5 to 20 times the volume of liquid to be supplied, but can be easily determined, including outside these values, by a person skilled in the art.

 The supply can be started and stopped by opening and closing the gas supply.

 The method described by the invention easily allows the control of several unitary liquid supply devices by a single opening of a gas valve controlling the supply of gas to several ascending tubes, possibly supplied with different liquids and possibly of different bit rates.

 In another embodiment, the liquid is scented and its combustion spreads a scent of perfume in the surrounding atmosphere. This is the case with a scented oil, for example pine essence.

 Figures 1 to 3 illustrate various embodiments of the invention.

- Figure 1 describes the basic principle of the invention.

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- Figure 2 illustrates in partial view an embodiment of the bubble chamber.

- Figure 3 illustrates a preferred embodiment of the invention.

 It should be understood that these illustrations in no way limit the scope of the invention and that it is only limited by the scope of the claims which follow.

 The device of FIG. 1 comprises a liquid reservoir 1, communicating at its base, by a conduit 2, with a bubbling chamber 3, which is surmounted by a small diameter ascending tube 4 and provided with a gas inlet 5 in the form, for example, of a nozzle, the level of which in said chamber is greater than the level of the outlet orifice 6 of the duct 2, so as to avoid a backflow of gas towards the liquid reservoir. The gas comes, through the conduit 7, controlled by the valve 8, from the gas tank 9. At the top of the rising tube 4 is disposed a burner 10, for example in the form of a grid or of a porous fire-resistant material . The level of liquid 11 in the reservoir is maintained above the level of the lower end 15 of the ascending tube and below the level of the upper end 16 of said ascending tube.

 The upper part of the bubbling chamber is in the form of a funnel widening downwards.

 The section of the ascending tube is sufficiently small and the section of the gas inlet sufficiently large for the gas to rise in said tube in the form of successive individual bubbles such as 13 and 17 each occupying almost the entire internal cross-section of the tube, each bubble being separated from the next by a portion of entrained liquid, such as 14 and 18. The gas flow is controlled so that the gas rises in the bubbling chamber towards the ascending tube in the form of successive individual bubbles and not as a continuous stream. The gas flow must also be low enough not to exceed the gas flow in the riser; otherwise, the gas would accumulate below the riser and no longer play its role as a carrier of portions of liquid.

 In FIG. 1, the gas is obtained by vaporization of a pressurized liquid 12 such as butane.

 To avoid a gas leak from the chamber 3 to the reservoir 1, the orifice 6 for the outlet of the liquid in the bubble chamber may include a check valve.

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 back or have a minimal section. This could for example be a micro-orifice, a narrow slot or a porous partition.

 In operation, the gas, for example butane, is ignited at the top of the riser. Depending on the nature of the compounds which have been dissolved in the liquid, flames (F) of different colors may be obtained.

d'une part supporte le joint 20 et d'autre part agit comme pointeau 25 pour fermer e ou ouvrir l'arrivée du gaz du tube 7. Cette remontée est provoquée par la détente du ressort comprimé 22, disposé à la partie inférieure de l'enceinte 19. Le gaz peut alors remonter dans la pièce creuse puis dans l'injecteur 5, dans la chambre 3 et dans le tube 4. Lorsque le ressort est entièrement détendu, le joint 20 ne remonte plus et la poursuite de l'élévation du tube 4 permet au liquide du réservoir 1 de pénétrer dans la chambre à bulles (3) en passant entre la base 24 de la chambre à bulles et le joint 20. Le gaz forme alors une colonne de bulles (non représentées) dans la chambre à bulles et ces bulles en remontant ensuite dans le tube 4 assurent l'entraînement de portions de liquide dans ce tube. FIG. 2 illustrates a particular embodiment of the bubble chamber 3 formed here by the lower part of the rising tube 4 In this embodiment, the rising tube 4 can be raised or lowered inside an external tubular enclosure fixed 19. The junction not shown here between the tube 4 and the enclosure 19 can be simple friction (for example O-ring) or better comprises a thread such as 23 (see Figure 3); in the latter case, the rotation of the tube 4 makes it possible to raise or lower it with more precision than in the case of simple friction. In the lowered position, the tube 4 rests on a seal 20, for example made of elastomer, and the liquid from the reservoir 1 placed in the upper part of the enclosure 19 cannot enter the bubble chamber 3. The rise of the tube 4 causes the seal 20 and a hollow part 21 to rise

on the one hand supports the gasket 20 and on the other hand acts as a needle 25 to close or open the gas supply from the tube 7. This rise is caused by the relaxation of the compressed spring 22, disposed at the lower part of the enclosure 19. The gas can then rise in the hollow part then in the injector 5, in the chamber 3 and in the tube 4. When the spring is fully relaxed, the seal 20 no longer goes up and the continuation of the rise of the tube 4 allows the liquid from the reservoir 1 to enter the bubble chamber (3) passing between the base 24 of the bubble chamber and the seal 20. The gas then forms a column of bubbles (not shown) in the chamber bubbles and these bubbles then going back into the tube 4 ensure the entrainment of portions of liquid in this tube.

 It will be noted that the enclosure 19 serves as a liquid reservoir in its upper part (above the seal 20) while in its lower part (below the seal 20) it allows the passage of the gas coming from the tube 7.

 FIG. 3 represents a complete installation capable of operating in a flame lamp and using as a gas source a tank of combustible liquefied gas such as butane. The liquefied gas tank 9 and the liquid tank 1 containing a flame dye are arranged one below the other, surrounding the ascending tube and the gas inlet, so as to produce a

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 self-contained one-piece set. The operation is the same as in FIG. 2 or FIG. 1 and the numerical references of FIG. 3 have the same meanings as in FIGS. 1 and 2. The references 23 and 27 to 29, which do not appear in FIGS. 1 and 2, have the following meanings: the reference 23 represents the screw pitch, or equivalent element, which makes it possible to raise or lower the tube 4. The reference 27 designates a liquid recovery pad such as a metal sponge, porous material or the like. Reference 28 represents the filling orifice of the liquid tank 1. Reference 29 represents a vacuum membrane or equivalent.

 The operation will be easily understood in the light of the description of Figures 1 and 2 and one can therefore be satisfied with a brief summary of this operation. When the tube 4 is raised by rotation of the latter around the thread 23, the spring 22 expands, the part 21 and the needle 25 are raised and the gas (for example butane vapor) can penetrate into the chamber surrounding the spring; from there the gas passes through the orifice 21a and goes back up into the tube 26 and the tube 4. When the spring is completely relaxed, the ascent of the tube 4 allows the liquid from the reservoir 1 to enter the bubble chamber 3 passing through the orifice 24 and to rise therein as far as the tube 4. As the reservoir 1 is not under pressure, the liquid cannot rise by itself to the top 16 of the tube 4. On the other hand, the gas forms individual bubbles (13,17) in the tube 4 and these bubbles allow the portions of liquid (14,18) to rise to the top of the tube 4. The gas mixed with the liquid can then be ignited at the top of the tube 4 either directly at the outlet of this tube or after passing through the porous buffer 27. There is thus a flame F which can be colored as a function of the compounds which have been dissolved or dispersed in the liquid of the reservoir 1.

 The following examples, which do not limit the invention, are intended to illustrate it.

EXAMPLES
Example 1
A mechanical assembly to be lubricated is equipped with a series of ascending tubes with an internal diameter of 4 millimeters, with a length between
15 and 50 centimeters, each equipped with a bubbling chamber supplied with oil by a supply network from a single loaded tank, the filling level of which is located 3 centimeters below the upper end

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 of the tube feeding at the lowest level, and 5 centimeters above the bottom end of the highest ascending tube, it being understood that, for all the tubes, the upper ends are at a level higher than said filling level and the lower ends are at a level lower than said filling level. The orifice of the gas inlet nozzles in the bubbling chambers has a diameter of 4 mm and forms bubbles with an average diameter of approximately 6 mm.

 The gas source is compressed air and the flow rate of each gas orifice is 1.3 liters per hour and the oil flow rate at the outlet of each of the tubes varies from 80 to 150 milliliters per hour depending on the length of the risers.

Example 2
A colored flame lamp is made up of the following components: A liquid tank (1) with a capacity of 250 milliliters is filled with a liquid made up of 94% (by weight) of dimethylformamide, 4% of lithium nitrate and 12% ammonium nitrate, the indicated salts being dissolved in the liquid.

This tank has a height of 6 cm and is provided with an air inlet at the top with anti-spillage device, and a liquid outlet bringing the latter by a small conduit (2) to the bubbling (3). This bubbling chamber, placed at the lowest part of the lamp, has a capacity of 2 milliliters; it is penetrated at the bottom by a gas supply tube terminated by an orifice (5) with a diameter of 1.5 mm forming bubbles of approximately 2 mm in diameter. On the top of the bubbling chamber, vertically above the gas outlet, is located the lower end of a stainless steel tube (4) with an outside diameter of 2 mm and d '' an internal diameter of 1.6 mm. This tube (4) is arranged vertically and has a length of 18 cm.

 The tube bringing the gas into the bubbling chamber is supplied by a liquefied butane tank (9) with a capacity of 25 grams provided with a control valve (8) equipped with an upstream throttle ensuring a flow rate of 5 grams per hour of gas during operation.

 At the top of the vertical tube and outside of it is arranged a metal wick (27) intended to retain the liquid leaving this tube during combustion.

 When the gas opening is activated, the butane gas leaves the top of the tube (4) in a small flow as indicated above and allows the ignition of a small flame the size of that of a lighter. After a few seconds, the liquid

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 ascends in small portions (14,18) separated by a train of gas bubbles (13,17) provided by the device of the invention at a rate of approximately 50 grams per hour. It ignites easily on contact with the small butane flame and produces a beautiful, stable red flame (F) with a height of approximately 5 to 6 cm, without risk of effusion. The lamp thus produced has an autonomy of approximately 5 hours.

 Due to the low gas flow rate ensuring the rise of the liquid, it is advisable not to lose the effectiveness of the latter, which could come from the dissolution of this gas in the liquid to be supplied. In the case where the chosen gas has appreciable solubility in the chosen liquid, the cited disadvantage would be avoided by the dissolution in the liquid of constituents reducing the solubility of the gas.

In Example 2, the addition of ammonium nitrate makes it possible to avoid a significant dissolution of butane in dimethylformamide.

Claims (20)

CLAIMS 1. Method for producing a flow of liquid at the upper end of an ascending tube with a small internal cross-section from a reserve of the liquid whose level is maintained both below that of the end upper of said ascending tube and higher than that of the lower end of this same tube, characterized in that: a) the reserve of liquid is placed in communication with a chamber, called bubbling chamber, communicating on the other hand, at its upper part, with the lower end of said ascending tube and on the other hand with a gas source via a gas inlet orifice which is located at a level of the bubbling chamber lower than the level of the lower end of the ascending tube, the section of the gas inlet orifice in the bubbling chamber being sufficient to produce in the liquid of the bubbling chamber bubbles of successive gases d have the cross-section is at least equal to the internal cross-section of the ascending tube, the communication of the liquid of the reserve with the bubbling chamber taking place away from the path of said gas bubbles, and b) while maintaining the reserve liquid level as indicated above, the gas is admitted into the bubbling chamber by passing through the gas inlet orifice at a rate sufficient to produce a succession of bubbles in the liquid, said rate being however less than that which would lead to an accumulation of gas bubbles in the top of the bubbling chamber, so as to let rise in the ascending tube said succession of gas bubbles separated by portions of entrained liquid and to release said portions of liquid at the upper end of said riser.  2. Method according to claim 1, characterized in that it is implemented in an ascending tube of internal section less than 1 square centimeter and preferably less than 10 square millimeters.  3. Method according to any one of claims 1 and 2, characterized in that it is implemented with a bubbling chamber whose cross section is greater than both the maximum internal cross section of the ascending tube and the cross section of the gas inlet in the bubbling chamber. <Desc / Clms Page number 13>  4. Method according to any one of claims 1 to 3, characterized in that it is implemented with an outlet for gas bubbles whose section represents from 75 to 200% of the maximum internal section of the ascending tube .  5. Method according to any one of claims 1 to 4, characterized in that the gas flow represents 5 to 20 times the liquid flow on a volumetric basis.  6. Method according to any one of claims 1 to 5, characterized in that the gas is combustible and in that one ignites and allows to burn the mixture of gas bubbles and liquid at the upper end of the ascending tube so as to operate as a flame lamp.  7. Method according to claim 6, characterized in that the ignition is carried out on the surface of a wire mesh, a sleeve of compacted metal wire or a non-combustible or hardly combustible porous body disposed at the end top of the riser.  8. Method according to claim 6 or 7, characterized in that the liquid contains in solution or in suspension at least one chemical compound chosen for the coloring of the flames which it provides, so as to operate in a colored flame lamp.  9. Method according to one of claims 6 to 8, characterized in that the mixture of gas bubbles and liquid is burnt at the upper end of the ascending tube in contact or mixed with an auxiliary flame.  10. Device comprising an ascending tube (4) communicating by its lower end with the upper end of a chamber called bubbling chamber (3), said bubbling chamber being moreover in communication on the one hand with a reservoir (1 ) for liquid and on the other hand with a gas source (9), said tank being capable of containing said liquid at a level which is both higher than the level of the lower end of the ascending tube and lower than the level of the upper end of said ascending tube, the communication between the bubbling chamber and the gas source taking place via a gas inlet orifice (5) situated at a level of the bubbling chamber lower than the communication level of said chamber with the lower end of the ascending tube and the communication between the bubbling chamber and the liquid reservoir taking place via at least one liquid admission orifice (6) sit ue away from the upward path followed by gas bubbles which can form when the bubbling chamber is filled with liquid and the gas is <Desc / Clms Page number 14>  admitted into said chamber, said device further comprising means for controlling the gas flow making it possible to admit it into the bubbling chamber in the form of a train of successive gas bubbles whose cross section is at least equal to the internal cross section of the riser.  11. Device according to claim 10, in which the upper part of the bubbling chamber (3) has the form of a funnel widening downwards, intended to receive the gas bubbles and to direct them towards the end. lower of the riser (4), the cross section of the bubbling chamber being greater than both the maximum internal cross section of the riser and the cross section of the gas inlet (5) into the chamber bubbling.  12. Device according to claim 10 or 11, wherein the bubbling chamber (3) is located at least partially inside the liquid tank (1).  13. Device according to claim 12, in which the liquid reservoir comprises a well at its base, and in which the bubbling chamber is arranged at least partly in said well.  14. Device according to any one of claims 10 to 13, wherein the ascending tube (4) has at all points an internal section less than 1 square centimeter and preferably less than 10 square millimeters.  15. Device according to any one of claims 10 to 14, wherein the section of the gas bubble outlet represents 75 to 200% of the maximum internal section of the riser.  16. Device according to any one of claims 10 to 15, comprising a burner (10) at the upper end of the riser tube, intended for the combustion of liquid and / or gas.  17. Device according to claim 16, in which the burner consists of a metallic fabric, a compacted wire sleeve or a non-combustible or hardly combustible porous body.  18. Device according to claim 16 or 17, further comprising an auxiliary gas burner disposed in contact with the burner of the upper end of the riser.  19. Use of the method according to any one of claims 6 to 9 or the device according to any one of claims 16 to 18 to produce <Desc / CRUD Page number 15>  a flame, the liquid and / or the gas being combustible (s) and the ignition being carried out at the level of the burner.  20. Use according to claim 19, in which the liquid contains in solution or in suspension at least one chemical compound chosen for the coloring of the flames which it provides.