EP0028025A1 - Method and device for the production of microdroplets of liquid - Google Patents

Abstract

To generate micro liquid droplets, a liquid jet is injected centrally into an atomizing chamber (12) to form a spray cone (17) and an external helical gas flow (13) is applied there. To further reduce the size of the droplets, the droplets (19) are introduced into a transport or reaction space (20) of a small overall length and are carried through this by a likewise helical gas flow (21). The transport or reaction space (20) is preferably delimited by a pot-shaped container, the liquid droplets (19) entering the transport or reaction space (20) on the end face opposite the open end. The method and the arrangement for carrying out the processing is particularly suitable for the practically soot-free combustion of flammable liquids, in particular oil.

Description

The invention relates to a method and a device for producing micro liquid droplets.

In a variety of chemical or physical processes, particularly drying and combustion processes, it is of great importance to obtain reactive microfluidic droplets. For this purpose, a liquid is normally pressed through a specially designed atomizing nozzle, which causes the liquid to be sprayed apart or atomized. Atomization can also be carried out with the help of steam or compressed air, these methods not being used for smaller liquid flows.

It is also generally known to improve or accelerate the exit of a liquid jet from a nozzle by a gas flow concentrically surrounding the emerging jet. However, the gas flow is not intended to atomize the liquid emerging from the nozzle, but rather, on the contrary, to hold the liquid jet together. Finally, it is also known to impart a rotational movement to the thin gas jacket holding the liquid jet or a sponge of droplets in order to thereby maintain a rotation of the liquid jet itself. However, atomization of the liquid jet or further fine atomization should also be avoided in this known solution.

The present invention is based on the object of creating a method and a device for producing microfluidic droplets which allow extremely fine atomization of the liquid even at very low liquid pressure.

• - aus einer Öffnung in einen Zerstäuberraum eine Flüssigkeit eingespritzt wird, derart, dass ein im wesentlichen hohler Sprühkegel entsteht, und dass
• - dieser Sprühkegel von einer äusseren Gasströmung beaufschlagt wird, deren Strömungsbahn etwa konzentrisch und schraubenförmig zur gedachten Achse des Sprühkegels verläuft, so dass der Sprühkegel durch die Gasströmung aufgebrochen wird.

This task is fiction, regarding the method resolved according to that

• - A liquid is injected from an opening into an atomizing chamber such that an essentially hollow spray cone is formed, and that
• - This spray cone is acted upon by an external gas flow, the flow path of which is approximately concentric and helical to the imaginary axis of the spray cone, so that the spray cone is broken up by the gas flow.

According to the invention, it is consciously and controlled that the liquid and the gas flow collide violently. This makes it possible to achieve fine atomization at very low pressure of the liquid emerging from the opening. The method according to the invention gives maximum fine atomization even with very small liquid flows.

Preferably, the radius of the helical flow path of the gas flow in the direction away from the opening through which the liquid is injected into the atomizing chamber is increasingly, preferably steadily, reduced. As a result, the gas flow experiences an additional acceleration, with the result that the entrained liquid droplets are broken up to an increased extent. Extremely fine liquid droplets or micro liquid droplets in the order of magnitude of about 20 μm are obtained. Such a small average droplet size cannot be achieved with the known atomizing nozzles or methods. A reduction in the average tube size below 50 _/ um mostly failed due to the manufacturing possibilities. There are spray nozzles for such coarse atomization / with uniformly distributed over the circumference Sprühschlitzen each having a width of about 100 _/ um. Since manufacturing tolerances between 98 / um and 102 _/ um can not be avoided, such spray nozzles lead to an unequal distribution of the atomization or to a non-uniform droplet distribution. Further, it has been found that approximately 100 _/ um wide Sprühschlitze with the use of liquid with solid particles (impurities), such as oil, can easily clog than liquid to be atomized in a short time. After this, after a long period of use, the droplets are distributed unevenly. The contamination can lead to wear, which also leads to an uneven distribution.

To further reduce the droplet size, it has been shown that it is advantageous to introduce the liquid droplets through an opening into a preferably cylindrical transport space and to carry them through a helical gas flow to the end opposite the inlet opening, which is preferably open.

It is known in the art to use a gas flow to transport fluid droplets ton from one point to another point along a straight path, the transport path being dimensioned such that the droplets chemically react or undergo a physical change as they move along this path, e.g. B. Evaporation. The solution according to the invention now has the advantage that the reactions mentioned can take place over a relatively short overall length of the transport space. This is of particular importance in the case of combustion devices in order to obtain an overall compact system.

wobei c eine Konstante ist.Die Prozesszeit t ist die notwendige Aufenthaltsdauer im Transport- bzw. Reaktionsraum, wobei durch die erfindungsgemässe Bewegungsbahn der Tröpfchen im Transportraum diese Zeit auch bei einem sehr kleinen Transportraum eingehalten werden kann.The latter solution thus provides an extremely long transport route for the liquid droplets entrained by the gas flow through a relatively short space. So that it is z. B. also possible, liquid droplets within a very small "reaction space" or transport space z. B. to bring to full evaporation. The inventive method proper It is particularly useful for drying and burning a liquid, because it is generally known that the smaller the droplets, the faster and more complete the drying or combustion. The relationship between the process time t (= drying or combustion time) and the droplet diameter d is as follows:

where c is a constant. The process time t is the necessary length of stay in the transport or reaction space, whereby this time can be maintained even with a very small transport space due to the movement path of the droplets in the transport space according to the invention.

In most cases, it must be avoided that the liquid droplets in the atomizing space and / or transport space or reaction space come into contact with the inner surface of the room wall. Corresponding deposits on the inner surface of the room walls should be avoided. In order to achieve this, the gas is introduced into the atomizing space and / or the transport space advantageously at a distance from the inner surface of the room wall.

In order to obtain an even greater refinement of the liquid droplets, a self-twisting or rotating movement can be impressed on the gas along the flow path. The gas flow is then characterized by two superimposed rotational movements.

In terms of the device, the object is achieved by the measures according to claims 10 to 23, the technical advantages of the claimed features being discussed in more detail below. The method according to the invention is explained in more detail below with reference to the preferred exemplary embodiments of the device according to the invention which are schematically illustrated in the accompanying drawings.

• Fig. 1a - 1d verschiedene Ausführungsformen von Flüssigkeits-Zerstäuberräumen im Schnitt,
• Fig. 2 eine schematische Darstellung einer Bewegung eines Flüssigkeitstropfens längs einer geraden Strecke innerhalb eines Transport- bzw. Reaktionszylinders,
• Fig. 3 die Bewegung eines Flüssigkeitströpfchens längs einer Bogenlinie,
• Fig. 4 - 6 drei verschiedene Ausführungsformen von Transport- bzw. Reaktionsräumen,
• Fig. 7 eine Kombination der Zerstäubereinheit gemäss Fig. 1a und Reaktionseinheit gemäss Fig. 6 zur Erzeugung feinster Flüssigkeitströpfchen,
• Fig. 8 eine Anordnung der Einheit gemäss Fig. 7 in einem Wärmetauscher, und
• Fig. 9 u. 10 graphische Darstellungen zur Demonstration der vorteilhaften Wirkung der Einheit gemäss Fig. 7.

Show it:

• 1a-1d different embodiments of liquid atomizing chambers in section,
• 2 shows a schematic representation of a movement of a drop of liquid along a straight line within a transport or reaction cylinder,
• 3 shows the movement of a liquid droplet along an arc line,
• 4 - 6 three different embodiments of transport or reaction rooms,
• 7 shows a combination of the atomizer unit according to FIG. 1a and the reaction unit according to FIG. 6 for producing the finest liquid droplets,
• 8 shows an arrangement of the unit according to FIG. 7 in a heat exchanger, and
• Fig. 9 u. 10 graphical representations to demonstrate the advantageous effect of the unit according to FIG. 7.

A good atomization of a liquid can be achieved by the atomizer units shown in FIGS. 1a to 1d, each consisting of a centrally arranged liquid tube 10, a concentrically surrounding cylindrical jacket 11 with a conically tapering atomizer chamber 12 and the outer circumference of the liquid tube 10 gas guide means or gas inlet openings 16 arranged obliquely to the longitudinal axis of the tube exist which pressure or pressure flow around the liquid tube 10 in the longitudinal direction. Impress atomizing gas a swirl movement 13.

The tube opening or liquid inlet opening 14 is designed such that the liquid jet 15 fans out conically (hollow spray cone 17) as it exits the opening 14.

This brings about a violent collision of the liquid with the gas flow 13, the gas flow 13 being accelerated in the direction of the atomizer chamber outlet opening 18 due to the constant reduction in the diameter of the helical gas flow. The gas flow thus breaks up the spray cone 17 into individual liquid droplets.

In Fig. 1c baffles 47 are arranged in the gas inlet openings for deflecting the gas flow.

In FIG. 1b, instead of the guide plates 47 in FIG. 1c, swirl grooves 48 are provided on the outer circumference of the liquid tube, which likewise impart a swirl movement to the atomizing gas. The end 49 of the liquid tube 10 protruding into the atomizing chamber 12 extends in the embodiment according to FIG. 1b to close to the outlet opening 18, so that an extremely violent collision of atomizing gas and emerging liquid takes place immediately before this opening. The liquid is virtually "blown up" immediately before it emerges from the atomizing chamber 12. In the embodiment according to FIG. 1b, the outer surface of the part of the tube 10 projecting into the atomizing chamber 12 is conical, corresponding to the atomizing chamber.

In the embodiment according to FIG. 1d, the liquid tube 10 is lengthened by a tube 50 inserted into the opening 14 thereof, which can preferably be arranged in a longitudinally displaceable manner therein.

In the conical jacket part which laterally delimits the atomizer chamber, gas inlet openings for the entry of secondary gas can also be provided in order to reliably avoid contact between the liquid droplets and the inner surface of the atomizer chamber wall and thus deposits on the latter. The secondary gas can also be compressed gas and is preferably introduced in such a way that the swirl movement 13 of the atomizing gas is additionally supported.

To chemical or physical reactions with the z. B. in the atomizer chamber 12 of the liquid droplets obtained in FIGS. 1a to 1d, these are moved through a transport space or reaction space along a predetermined path. 2 and 3 each show cylindrical transport spaces 20 which are each open at the right end. A droplet 19 is moved from a point A to a point B. On this route the droplet z. B. evaporate. FIG. 3 shows that when the droplet moves along an arc line, the distance between points A and B is less than when moving along a straight line (according to FIG. 2). The effective movement distance is of course the same. 3, however, the movement in the second dimension is used, which leads to a shortening of the distance between the two end points of the movement path.

Following this finding, in the solution according to the invention the droplets are guided or carried along the three-dimensional path through the transport or reaction space 20.

In the embodiment according to FIG. 4, the droplets 19 enter the transport space 20, which is delimited by a cup-shaped container with a side wall 28, through a droplet inlet opening 22, which is located in the center of the end face of the cup-shaped container. At a radial distance from the opening 22 there are a plurality of openings 24, which are evenly distributed over the circumference, for the gas entry into the transport space 20, wherein in the openings 24 there are respectively inclined guide plates or blades 26, which form a helical gas flow around the longitudinal axis 9 of the transport - or effect reaction chamber 20.

5 is very similar to the embodiment of FIG. 4, with the only difference that the gas inlet openings 24 are located in the side wall 28 of the pot-shaped container. In this case, more than one gas inlet opening 24 can be provided. The gas inlet openings 24 are inclined to the radial (as section A-A clearly shows) in order to impart a predetermined screw movement through the transport space 20 to the gas flow (see arrows). The inner diameter of the pot-shaped housing can be dimensioned such that the gas flow practically no longer acts on the inner surface of the side wall 28. This eliminates the danger or their reaction products of a deposit of liquid droplets on the inner surface of the side wall 28. Such deposits would lead to a change in the flow conditions and would require cleaning of the transport or reaction space 20 after a certain period of operation.

To ensure that the droplets do not deposit on the inner surface of the side wall 28, the inner surface of the side wall can be inserted into the openings 24 28 protruding tubes 30 are used (cf. FIG. 6 with a corresponding section BB).

To adapt to different droplet sizes, reaction times of the droplet material, etc., it can be advantageous if the tubes 30 are slidably inserted within the openings 24, so that the length of the part projecting beyond the inner surface of the side wall 28 can be changed. The easiest way to solve this problem is to screw the tubes 30 into the openings 24.

As already explained further above, the jet direction of the openings 24 or the tubes 30 can preferably also be changed for the purpose of adaptation to different droplet sizes, etc.

FIG. 7 shows a combination of the atomizer unit shown schematically in FIG. 1 and the transport or reaction unit shown schematically in FIG. 6. The liquid droplets generated in the atomizer chamber 12 pass through the atomizer chamber outlet openings 18 or droplet inlet opening 22 into the transport space 20, where they experience an approximately conical fanning out, which is surprisingly conveyed by the gas introduced through the tubes 30. Evidently, a negative pressure is created in the annular space between the closed end face of the transport space 20 and the gas tubes 30, which pulls the liquid droplets emerging from the opening 22 radially outwards. This will take the liquid droplets 19 by the shortest route in the area of the gas flow shown in Fig ^- 7 characterized by the reference numeral 21..

In order to additionally increase the fanning out of the liquid droplets introduced into the transport space at a distance from the liquid droplet inlet opening 22, a distributor body 32 is arranged, the side of which is oriented toward the opening 22 is flat. Depending on the external parameters, such as gas entry speed, droplet size, etc., the plane of the distributor body 32 facing the opening 22 can also be convex or conical.

The distributor body 32 thus favors rapid mixing of the droplets with the gas flow 21, the degree of mixing being able to be set by the shape of the distributor body 32. The distance between the distributor body 32 and the opening 22 also has an influence on the degree of mixing or fanning out of the liquid droplets introduced into the transport space. In order to vary the degree of mixing or fanning out, the distributor body 32 is therefore preferably mounted such that it can be moved back and forth in the direction of the longitudinal axis 9 of the transport or reaction space 20. Good results can be achieved if the distributor body 32 lies in a plane between the droplet inlet opening 22 and the plane defined by the gas tubes 30 close to the same. The distributor body 32 promotes in particular the uniform distribution of the introduced droplets 19 over the cross-section of the transport or reaction space 20. The distributor body 32 thus prevents local droplet accumulations, as a result of which uniform mixing into the gas stream 21 is achieved. In the exemplary embodiment according to FIG. 7, the distributor body 32 is fastened to a stiff wire. However, other fastening options are also conceivable, although care must be taken to ensure that the fastening means do not adversely affect the flow, in particular the swirl movement of the gas-droplet flow in the transport space 20.

If the transport space or reaction chamber 20 to serve as a combustion chamber, in this still preferably a Zündeinrichtun ^g / provided in the area of the droplet inlet port 22 to the combustion of the liquid droplets, z. B. oil droplets to start.

In FIG. 8 the unit according to FIG. 7 is used as an oil burner and is identified by the reference number 41. The burner 41 is attached to the upper end of an upright heat exchanger 42, the transport or reaction space 20 projecting slightly into an exhaust gas space 43. In the application example shown schematically in FIG. 8, the reaction chamber 20 serves as the combustion chamber, the flame 44 slightly knocking out of the combustion chamber 20. The hot combustion gases are passed through the exhaust gas space 43 in accordance with the arrows 45, a tubular radiation body 34 being arranged concentrically inside the exhaust gas space 43 at the end remote from the burner. The outside diameter of the tubular radiation body 34 is somewhat smaller than the inside diameter of the exhaust gas chamber 43, which is also tubular in the embodiment shown. Both the radiation body 34 and the wall of the exhaust gas space 43 are preferably made of heat-resistant metal (steel) and have a dark, preferably black color, so that they serve as ideal radiation bodies. The additional radiation body 34 and the exhaust pipe delimiting the exhaust gas space 43 promote the heat exchange between the hot combustion gases and the environment, in the present case a heat exchange medium 38, which is passed at a distance from the exhaust pipe. the exhaust pipe as well as between the hot combustion gases and / in particular the black radiation body 34 is heated exchange by convection. The heat absorbed by the exhaust pipe and / or radiation body 34 is emitted again by radiation to the environment or to the heat exchange medium 38 and transported through this to another location.

In addition to the tubular radiation body 34 or instead, black radiation bodies, which are “flushed” by the hot combustion gases, can also be arranged behind the outlet of the exhaust pipe or in the gas guide channels 46 extending through the heat exchanger 42. The shape of the radiation body can e.g. B. be egg-shaped. However, tubular radiation bodies can also be used again. Of course, care must be taken to ensure that the arrangement of the radiation bodies in the gas guide channels does not cause excessive pressure drops.

The black radiation bodies are made of metal, preferably of heat-resistant, stainless steel. But they can just as well be made of ceramic or stone. The material depends on the gas flowing around the radiation body or the chemical and / or physical reactions taking place in the reaction space 20.

If the radiation bodies are arranged relatively far from the combustion flame, the flame temperature and thus the combustion are not influenced by the radiation bodies.

If the radiation bodies are arranged in the immediate vicinity of the flame or the reaction site, a cooling effect is achieved by the radiation bodies, which dissipate heat to the outside, ie to the environment. B. causes the reaction rate is reduced or a reaction does not take place at all (e.g. cracking processes).

In some chemical or physical processes, it may also be necessary to apply heat from the outside to allow the reactions to take place. Up to now, this has usually only been accomplished by heating the reaction space by means of a heater or the like. It has now been shown to be significantly intensify the heat transfer from the outside into the reaction chamber by using the _ch orbeschrie- surrounded radiant body in the reaction chamber /. The radiation bodies arranged in the reaction space enable additional heat to be supplied by means of heat radiation.

The radiation bodies are also particularly suitable for the controlled afterburning of exhaust gases in an exhaust duct. For this purpose, the radiation bodies are arranged in the exhaust duct at a suitable distance from the combustion flame and are heated from the outside by heat radiation. The heat then emitted from the radiation body to the exhaust gases by means of convection causes the exhaust gases to re-ignite, so that complete combustion is achieved before the exhaust gases exit into the open. As can be clearly seen from the above, the described invention is particularly suitable for an oil burner. Therefore, the conditions in an oil burner and the advantages achieved by the solution according to the invention are discussed in detail again below.

wobei

• ṁ = die Massendurchflussrate pro Masseneinheit eines Tröpfchens,
• d = der Tröpfchendurchmesser,
• c_y= die Konzentration des "Öldampfes" an der Tröpfchenoberfläche,
• c_f= die Dampfkonzentration in der Flamme,
• δ = die Dichte des Öls bei Tropfentemperatur, und
• B = der Transferkoeffizient für den Dampf

bedeuten.There are many methods to reduce soot formation in an oil burner. Some of these methods are e.g. B. in a publication by Peterson and Skoog "Stoftbildning vid oljeeldning", Stockholm, 1972, described in more detail. The known methods relate primarily to the use of heavy oils. Among these known methods, the use of an emulsion of oil and water has been found to be the most suitable. However, this process cannot avoid the formation of small _{soot particles} that _lead to aggressive SO ₃ concentrations if light oils are used as fuel. The formation of these small soot particles, which are dangerous for human lungs, can be reduced by improving combustion. The combustion intensity or mass flow rate that is burned per unit mass of oil can be defined as follows:

in which

• ṁ = the mass flow rate per unit mass of a droplet,
• d = the droplet diameter,
• c _y = the concentration of the "oil vapor" at the droplet surface,
• c _f = the vapor concentration in the flame,
• δ = the density of the oil at drop temperature, and
• B = the transfer coefficient for the steam

mean.

• a) einerReduzierung des Tröpfchendurchmessers,
• b) einer Zunahme des Wertes von c_y, der durch Erhöhung der Öltemperatur, z. B. durch Vorwärmung, erhöht werden kann, und
• c) einerErhöhung des Wertes von B, der durch folgende Gleichung bestimmt wird:
  
  wobei
• D = der Diffusionskoeffizient,
• _Pf = der Partialdruck entsprechend dem Wert von c_y, und
• P_tot = der Gesamtdruck in der Brennzone

bedeuten.From the above equation (1) it can be seen that the combustion intensity increases with:

• a) a reduction in the droplet diameter,
• b) an increase in the value of c _y caused by an increase in the oil temperature, e.g. B. can be increased by preheating, and
• c) an increase in the value of B, which is determined by the following equation:
  
  in which
• D = the diffusion coefficient,
• _Pf = the partial pressure corresponding to the value of c _y , and
• P _tot = the total pressure in the firing zone

mean.

The application of equation (2) is limited to the case in which there is no influence of a relative movement between the droplet and the environment.

As can be seen from equation (2), the value β - and consequently the value m - can be increased by increasing the temperature of the environment around the oil droplet, usually the air atmosphere, since the value of D is temperature-dependent and -dD / dT> 0 is. The droplet size is therefore of great importance, since smaller droplets lead to a higher value of B.

• - kleine Öltröpfchen,
• - höhere Temperaturen des die Tröpfchen umgebenden Mediums, meist Luft.

In summary, it follows that the combustion can be improved by

• - small droplets of oil,
• - higher temperatures of the medium surrounding the droplets, mostly air.

The first condition is optimally met by a nozzle according to FIGS. 1a to 1d. The second condition can very easily be met by introducing preheated air into the atomizing chamber 12 and optionally the reaction chamber 20.

The third condition can also be very simple by preheating the oil to be burned.

As has already been explained in detail above in connection with the reaction space 20, the screw movement of the liquid droplets through the reaction space according to the invention achieves a sufficient residence time for the droplets in the reaction space 20 for complete combustion although the reaction space 20 is of very short construction. The short construction of the reaction space 20 has the additional advantage that heat radiation losses in the area of the reaction space are correspondingly low.

Despite the short construction of the reaction space 20, complete combustion in this space is thus ensured in the solution according to the invention.

Tests have shown that the soot formation when using the method according to the invention or using the device according to the invention according to FIG. 7 is almost zero. It has proven to be advantageous if, when the atomizer chamber and transport or reaction chamber are arranged one behind the other, about 15% of the compressed gas available is introduced into the atomizer chamber and 85% into the transport chamber. The speed of the compressed gas introduced into the transport space, e.g. B. air, is preferably between about 50 to about 150 m / second. These values have proven to be particularly advantageous, in particular excess air is avoided, which leads to undesired S0 ₃ formation. A low S0 ₃ formation also results in a decrease in soot formation, as has already been the case by Gaydon et al in Proc. of Royal Society, London, 1947.

A few words about the formation of nitrogen oxides should be mentioned below. Nitrogen oxides (NOX) are especially dangerous for animals /. For this reason, laws in many countries require that the nitrogen oxide concentration in exhaust gases must not exceed a certain value. In Germany, the nitrogen oxide concentration in oil burners (operated with heavy oil) must not exceed 500 ppm in the exhaust gas.

• - dem Anteil von Stickstoffatomen in den Öl bildenden Substanzen.Etwa 50 % der Stickoxide, die bei der Verbrennung entstehen, stammen unmittelbar von den Öl bildenden Komponenten,
• - der Bildung von Stickoxiden bei der Verbrennung.

The formation of nitrogen oxides is a consequence of

• - The proportion of nitrogen atoms in the oil-forming substances. About 50% of the nitrogen oxides that are produced during combustion come directly from the oil-forming components,
• - The formation of nitrogen oxides during combustion.

• - eine Erhöhung der Flammentemperatur vermindert die Entstehung von N0,
• - geringer Luftüberschuss fördert die Bildung von NO,
• - die Bildung von NO ist sehr stark abhängig von der Zeit, die für die Bildung zur Verfügung steht. Es wird in diesem Zusammenhang auf die Fig. 9 hingewiesen, in der die Entstehung von NO-in Abhängigkeit von der Verweilzeit der Verbrennungsgase im Brennraum graphisch dargestellt ist. Aus Fig. 9 geht auch hervor, dass die Entstehung von NO von der Brennlufttemperatur abhängt.

The latter produces NO and N0 ₂ . The formation of NO has been intensively investigated. The following results were obtained:

• an increase in the flame temperature reduces the formation of N0,
• - low excess air promotes the formation of NO,
• - The formation of NO is very dependent on the time available for the formation. In this connection, reference is made to FIG. 9, in which the formation of NO as a function of the residence time of the combustion gases in the combustion chamber is shown graphically. 9 also shows that the formation of NO depends on the combustion air temperature.

When the unit according to FIG. 7 is used as an oil burner, the small design (extremely short reaction space 20) results in a correspondingly short residence time for the combustion gases. Furthermore, the burning time is reduced to a minimum even due to the extremely small liquid or oil droplets. The residence time of the droplets and exhaust gases in the unit according to FIG. 7 is approximately 0.07 seconds. According to FIG. 9, approximately 20 ppm NO are formed when the unit according to FIG. 7 is used as an oil burner. With this short dwell time, it hardly matters if the combustion air is preheated. As has been explained above, preheating the combustion air improves the combustion itself or the combustion intensity.

In FIG. 10, the NO values of an oil burner designed according to the invention are again shown schematically in comparison to conventional oil burners, specifically as a function of the oil flow rate (l / h) and the oxygen content during combustion.

The use of the device according to FIG. 7 with an atomizer unit and reaction unit as an oil burner thus leads to an optimal, soot-free combustion with extremely low excess air with an efficiency of at least 92%.

All features disclosed in the documents are claimed as essential to the invention, provided that they are not anticipated individually or in combination by the prior art.

Claims (23)

1. A method for producing micro liquid droplets, characterized in that - A liquid is injected from an opening into an atomizing chamber, in such a way that a substantially hollow spray cone is formed, and that - This spray cone is acted upon by an external gas flow, the flow path of which is approximately concentric and helical to the imaginary axis of the spray cone, so that the spray cone is broken up by the gas flow. 2. The method according to claim 1, characterized in that the radius of the helical flow path of the gas flow in the direction away from the opening, through which the liquid is injected into the atomizing chamber, is increasingly, preferably steadily, reduced. 3. The method according to claim 1 or 2, characterized in that the atomizing gas is introduced under pressure into the atomizing space. 4. A process for producing micro liquid droplets, characterized in that - After atomization of the liquid in droplets, in particular according to the method according to one of claims 1 to 3, these are introduced through an opening into a preferably cylindrical transport space and - Carried by this from a helical gas flow to the end opposite the inlet opening. 5. The method according to claim 4, characterized in that the droplets in the region of the imaginary axis of the helical gas flow enter the transport space. 6. The method according to any one of claims 1 to 5, characterized in that the gas flow direction in the transport space is chosen to be the same as that in the upstream atomizing space. 7. The method according to any one of claims 1 to 5, characterized in that the gas flow direction in the transport space is chosen opposite to that in the upstream atomizing space. 8. The method according to any one of claims 1 to 7, characterized in that the gas introduction into the atomizing space and / or transport space at a distance from the inside Surface of the room wall takes place in such a way that contact of the liquid droplets with the inner surface of the room walls is avoided. 9. The method according to any one of claims 1 to 8, characterized in that the gas performs a self-twisting or rotating movement along its flow path. 10. Device for producing micro liquid droplets, in particular for carrying out the method according to one of claims 1 to 9,
marked by - A liquid tube (10) which opens approximately centrally in an atomizing chamber (12), and - By gas inlet openings (16) arranged at a radial distance from the tube opening (14), which are designed such that they impart a helical movement through the gas blown into the atomizing space (12). 11. The device according to claim 10, characterized in that the cross section of the atomizing chamber (12) in the flow direction preferably decreases continuously up to the outlet opening (18). 12. The device according to claim 10 or 11, characterized in that the liquid tube (10) is extended to just before the outlet opening (18) of the atomizing chamber (12). 13. Device for producing micro liquid droplets, characterized by - a, preferably cylindrical liquid droplet transport space (20) following an atomizing space, preferably according to one of claims 10 to 12, at one end of which a droplet inlet opening (22) is provided and the opposite end of which is preferably open, and by - Gas inlet openings (24) which are arranged at a radial distance from the droplet inlet opening (22) and are designed such that they impart a helical movement through the gas introduced into the transport space (20). 14. The apparatus according to claim 13, characterized in that at least one opening (24) is provided for the gas inlet on the end of the transport space (20) opposite the open end, and that in the opening baffles (26) or the like. For the deflection of the gas introduced into the space (20) are arranged. 15. The apparatus according to claim 13, characterized in that at least one bore (24) or the like which extends obliquely to the radial is provided on the side wall (28) which laterally delimits the transport space for the gas inlet. 16. The apparatus according to claim 15, characterized in that a tube (30) projecting beyond the inner surface of the side wall (28) is inserted into the bore (24), so that contact of the liquid droplets carried by the helical gas flow through the transport space during their transport is avoided with the inner surface of the side wall. 17. The apparatus according to claim 16, characterized in that the length of the tubes (30) projecting into the transport space (20) is adjustable. 18. Device according to one of claims 15 to 17, characterized in that the bore (24) is also slightly inclined in the direction of flow. 19. Device according to one of claims 10 to 18, characterized in that in the transport space (20) at a distance from the droplet inlet opening (22) a distributor body (32) is provided, which for radial fanning out and uniform distribution over the cross-section of space in the transport space introduced droplet is used. 20. The apparatus according to claim 19, characterized in that the distributor body (32) is a plate with a flat or convex surface. 21. Device according to one of claims 13 to 20, characterized in that behind the transport space (20) dark, preferably black radiation bodies (34) are provided which absorb the heat absorbed by convection from the droplet-gas mixture or reaction gas by radiation give the environment. 22. The apparatus according to claim 21, characterized in that a tube section which is arranged concentrically in a channel (42) following the reaction space (20) serves as the radiation body (34). 23. Device according to one of claims 13 to 22, characterized in that the ratio of the length of the transport or reaction space (20) to its average diameter is approximately 1: 1, preferably 5: 3.

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