RU2228223C2 - Liquid spraying device and method - Google Patents

Abstract

FIELD: controllable liquid spraying including particle/droplet dispersion with the purpose of flow velocity, temperature and concentration measurement on the basis of laser usage; atomic analysis with flame and plasma use; ultra-fine powder production; spray drying for fine particles production; sprayers for sub-micron droplets obtaining, fuel atomizing into combustion chamber where particle dimensions are important. SUBSTANCE: spraying device is formed as heating tube having inlet and outlet ends. Liquid is heated during moving through tube, which results in evaporation thereof at tube outlet when liquid passes into space having low-pressure. Tube is electrically heated by transmission of electrical current with the possibility of quick heating process regulation for droplet diameters change during sprayer operation. Different sprayer embodiments are also presented. EFFECT: possibility of forming particles having diameters within desirable diameter range, possibility of changing droplet diameter range, possibility of setting droplet mean diameter. 23 cl,13 dwg

Description

Field of Invention

The present invention relates to a method and apparatus for spraying liquids. More specifically, liquid is sprayed at the outlet of an elongated small-diameter tube or chamber with a small internal surface area using an additional heating device for directly heating the liquid within the tube or chamber. Spray devices are widely used, including but not limited to: flame and plasma atomic spectroscopy; production of a powder having nanometer particle sizes; particle dispersion, droplets for flow diagnostics based on the use of lasers; spray drying for the production of fine powders; atomizers for inhalation in the supply of a therapeutic agent, as well as for spraying fuel for use in combustion chambers.

Level of invention

Sprayers are already widely used to create finely divided aerosols with a uniform distribution of droplet sizes. While some of the atomizers according to the prior art are at least partially effective, there is still a need for an atomizer that can produce finely atomized droplet dust with a controlled and uniform distribution of droplet sizes. An article in the journal Analytical Chemistry, 1990-62, pages 2745-2749, entitled: "Conversion of an Ultrasonic Humidifier to a Continuous-Type Ultrasonic Nebulizer for Atomic Spectrometry" by Clifford et al. Describes the most commonly used solution atomizers for atomic spectrometry. US Pat. No. 4,582,731, to Smith, published April 15, 1986, describes molecular spraying of films using supercritical fluid flowing, as well as a method for forming a powder. Particle generation and scattering in the laser velocity measurement technique is described by James F. Meyers in a 1991-08 lecture series published by the Institute for the Study of Fluid Dynamics: von Karman Institute for fluid dynamics. This link also describes an increase in the accuracy of laser measurements when particles of uniform sizes are used. A spray device for delivering medications is described by Greenspan et al., US Pat. No. 5,511,726, published April 30, 1996. The device uses a piezoelectric crystal and a control circuit to apply voltage to the sprayed solution.

In addition to the aforementioned atomizers of the prior art, in recent years various methods and devices have been developed for preheating or atomizing the fuel. Although some of these devices are relatively efficient, there is still a need for a spray gun that can fully convert the fuel to vapor, as well as increase the temperature of the fuel to avoid condensation at the outlet of the spray gun. This procedure is especially necessary during the cold start and warm-up cycle of the internal combustion engine. After the engine has been cooled significantly below the operating temperature (for example, a few minutes after it is turned off, depending on the weather), and then it was turned on, the fuel entering the combustion chamber is often in a vaporous state, in the form of large drops and in the form of a liquid. A significant part of the fuel, which is in the form of droplets or in the form of a liquid, does not completely burn out. This leads to a decrease in the efficiency of the engine (using unburned fuel), as well as to an increase in the release of unburned hydrocarbons. The engine is not only insufficiently heated to efficiently burn unsprayed fuel, but after processing (i.e. a catalytic converter) it is inoperative during this period, which creates severe pollution. In fact, seventy to eighty percent of all hydrocarbon emissions are produced before the catalytic converter begins to operate. By reducing the size of the fuel droplets and increasing the degree of vaporization of the fuel entering the combustion chamber, the percentage of fuel that burns increases, thereby generating more heat and reducing the time required to bring the engine and catalytic converter to operating temperature.

US Pat. No. 4,011,843, filed by Feuerman and published March 15, 1977, describes a fuel vaporization process for use in internal combustion engines. A spray valve for injected fuel of an internal combustion engine is described in US Pat. No. 4,898,142, published February 6, 1990, owned by Van Wechem et al. US Pat. No. 5,118,451, published June 2, 1992 and owned by Lambert, Sr. et al., another fuel vaporization device is described. US Pat. No. 5,609,297, published March 11, 1997, pending Gladigow et al., Describes several embodiments of fuel atomization devices. The fuel injector with an internal heater is described in US Patent No. 5758826, published June 2, 1998, and owned by Nines. US Pat. No. 5,778,860, published July 14, 1998, owned by Garcia, describes a fuel vaporization system. SAE Technical Paper Series # 900261, entitled "The Effect of Atomization of Fuel Injectors on Engine Performance" by Kashiwaya et al., Describes the use of turbulent injectors. SAE Technical Paper Series # 970040, entitled “Fuel Injection Strategies to Minimize Cold-Start HC Emissions,” by Fisher et al, describes the effect of changes in fuel injector and control parameters on cold start emissions. SAE Technical Paper Series # 1999-01-0792, published by Zimmermann et al., Describes the measurement of the effect of internally heated fuel injectors on hydrocarbon emissions until the engine reaches operating temperature.

SUMMARY OF THE INVENTION

The present invention includes controlled spraying of liquids for various applications, such as: dispersion of particles, droplets for measuring flow velocity, temperature and concentration based on the use of lasers; atomic spectroscopy using flame and plasma; production of a powder having nanometer particle sizes; spray drying to produce a uniform powder; chemical treatment (i.e. phase transformation, dispersion, catalysis and fuel conversion); atomizers for inhalation applications, as well as for spraying fuel for use in combustion chambers. In these and other atomizer applications, controlling the size and uniformity of droplets and / or particles is critical. In some applications, extremely small droplets (less than a micron) are preferred, while in others droplet diameters of a few microns are required. However, in most applications, thoroughly dispersed droplet dust with sufficiently uniform droplets (i.e., monodispersed) is required. In other applications, extremely finely divided droplets are required to provide an increased surface area for interaction, to improve reactions, ensure thermal and chemical equilibrium rates, phase transformations and achieve uniformity. The nebulizer of the present invention has such flexibility in forming droplets with controllable sizes that not only the average droplet size can be ensured, but also a range of sizes can be provided. Methods for using the nebulizer are described below with reference to specific applications.

The use of laser technology in the field of measurement has increased substantially over the past few decades, and this use continues to expand more and more as new and improved technologies develop. The advantage of laser technology is that the radiation is non-intrusive and non-destructive, and the focused radiation intensity inherent in laser beams allows for very accurate perception of very small particles, making very slight changes. One such application is the use of laser beams in order to perform velocity measurements, known as a laser Doppler velocity meter. The laser beam is directed at moving particles, and the particle velocity is measured. Often this type of measurement is used to study the velocity characteristics of a gas stream, such as air passing through a pipeline. In order to provide a target for the laser beam, which will reflect the beam both in air and other gases, it is necessary to introduce some medium, which is large enough to be illuminated. For demonstration measurements, a similar procedure is usually performed with smoke. However, measurements such as laser Doppler measurement usually require slightly larger particles, ranging from submicrons to several microns. In addition to dimensional sensitivity, the reflective medium can also change measured parameters. In order to study the velocity characteristics of the gas stream, it is necessary to “disperse” the gas stream with a sufficient number of particles from submicron sizes to several microns in size to make measurements possible, at the same time without affecting the gas stream or causing its degradation. Such a dispersion requirement is often the most difficult requirement in order to achieve accurate and reliable laser Doppler velocity measurements. Spray devices are currently used for dispersion, but they usually do not provide the required quality. The combination of small volume and inadequate atomization results in too few measurements for the required time period. For example, in order to carry out high-speed measurements, it is necessary to register several thousand measurements in one minute. These measurements can then be averaged to provide accurate results.

The present invention relates to a method and apparatus that is capable of generating droplet dust with small droplets, uniform in size, by means of a superheated atomizer. Such an atomizer was tested as a particle dispersion device for laser Doppler measurements, and it was shown that it provides a significant improvement in the number of samples per minute and signal-to-noise ratios. The improvement is due to the excellent ability of the nebulizer to accurately atomize the liquid in precise doses through the operation of a heating-based atomization method, as opposed to air-induced atomization. In a superheated atomizer, the pressurized liquid is heated to a high temperature in the atomizer nozzle, which leads to heated droplet dust, which is more resistant to re-condensation. Such stability is advantageous because the atomized droplet dust passes into the measuring part without re-condensation. It is expected that improvements in particle scattering for laser Doppler measuring systems that are achieved using the present invention can also improve measurement performance in other systems that use particle scattering, such as wind tunnel tests. In conclusion, the nebulizer according to the present invention was tested for spraying a liquid with suspended particles. The particles used in the test were titanium dioxide particles having sizes in the range of 3-5 microns. The atomizer provided excellent atomization and thus achieved uniform capture of titanium dioxide particles in the air stream in relation to zero buoyancy force. These test results show that the atomizer can be used as a smoke generator for wind tunnel tests. A stable, dense, reproducible and controlled volumetric flow of smoke was easily produced by the atomizer.

It has been demonstrated that the nebulizer according to the present invention can achieve data acquisition rates that are two to three orders of magnitude higher than the data acquisition rates available using known particle nebulizers. By optimizing the flow of liquid and gas, as well as the input power of the atomizer, you can get an additional increase in sensitivity for a wide range of materials and particles. In addition, the use of a nebulizer as a particle diffuser for flow measurements will allow for precise control of the size and density of droplets on the fly. Currently, solid dispersible particles with a fixed size distribution should be replaced between measurement cycles with different flow parameters, which require different particle sizes. In short, the atomizer can control the size of the droplets and their spatial distribution, as well as optimize signal levels, while reducing the interaction of particles with the flow field.

Another nebulizer application is in the field of elemental analysis using flame and plasma. In US patent No. 5997956 published by Hunt et al. On December 7, 1999, entitled: "Chemical vapor deposition and powder formation using thermal spray with near supercritical and super-critical fluid solutions", one embodiment of a nebulizer is described in combination with a gas deposition process with combustion. In such a coating process, the starting materials are dissolved in a solvent acting as a combustible fuel. This solution is sprayed to form droplets of submicron sizes that the oxygen stream carries to the flame where they ignite. The heat from the flame provides the energy necessary for both the droplets and the starting materials to evaporate in order to react and settle on the substrates. By modifying the vapor deposition with combustion of the system, measurements of the optical radiation of the samples excited in the flame can be performed, and these measurements can be analyzed for the presence of microimpurities. One such application includes flame-based atomic emission spectroscopy. Two of the most commonly used analytical methods for elemental analysis are atomic absorption spectroscopy and ion-cyclotron-plasma atomic emission spectroscopy. Atomic absorption spectroscopy devices are relatively inexpensive, but have somewhat limited sensitivity (detection limit). Ion-cyclotron-plasma atomic emission spectroscopy has a much greater sensitivity than atomic absorption spectroscopy, but it is also much more expensive. It has been demonstrated that the atomizer of the present invention can produce flame samples for atomic emission spectroscopy such that the measurements have a sensitivity comparable to the results obtained by atomic absorption spectroscopy of the prior art. Such sensitivity was achieved without fundamental modifications of the existing system of deposition from the gas phase with the combustion of the installation, and the resulting system was far from optimum. By optimizing the flow of liquid and gas, installing the atomizer, arranging the flame, integrating the signal and installing the optics, a significant increase in sensitivity can be obtained. The atomizer according to the present invention will provide high-quality results of ion-cyclotron-plasma atomic emission spectroscopy, and such a device could sell very well, being in the price range of atomic absorption spectroscopy devices. In atomic spectrometry, effective atomization of organic solutions and a decrease in the average droplet size increase the sensitivity of measurements and the efficiency of anolyte transfer. In addition, the kinetics of the vaporization process that occurs in the measuring chamber is determined by the fraction of large aerosols in the chamber, which directly correlates with the average diameter of the primary aerosol droplets produced by the atomizer.

The potential use of such a spray device in flame emission spectroscopy was established by preliminary tests using toluene solutions with known sodium concentrations. In order to observe the intensity “D” of the sodium line for solutions with different concentrations, a fiber-optic spectrometer was used. The lowest concentration tested (1 ppm) was easily detected, with sodium lines having a visually estimated signal to noise ratio much greater than 10: 1, even at such a low concentration. It was found that the system is very sensitive to small changes due to factors such as droplet dust uniformity, nozzle position, etc. The system of the present invention has a sensitivity that could compete with the ion-cyclone-plasma detection limits in terms of the cost of the equipment. In addition, this system can use hydrocarbon solutions. In order to reduce background peaks of the solvent, the present invention can be used in an ion-cyclone-plasma system or with an oxygen-hydrogen flame. Other types of plasma can also be used, for example, a type of microwave and electric arc plasma. In such plasma systems, increased sensitivity will be achieved using the present invention due to finer atomization and due to little or no dissolution from atomizing or propagating gases.

The atomizer can also be used in the manufacture of powders having nanometer particle sizes (1-100 nm). There are many technologies for the production of fine powders, including chemical vapor deposition, flame deposition, and plasma treatment. Such methods are necessary for the production of a homogeneous powder with a small particle size, but they consume a lot of energy and therefore expensive. Compared with these methods, the present invention provides a significant reduction in processing costs. In addition, the spraying process will also allow the production of numerous dust formulations with nanometer-sized particles that cannot be obtained by conventional methods. In methods of condensing vapor of a burning liquid, cheap metal-carrying reagents that do not react with surrounding materials are dissolved in solvents, which also serve as combustible fuel. When using the nebulizer according to the present invention, this solution is atomized in order to form submicron droplets, which then ignite in a flare, forming a vapor. The condensable samples thus formed homogeneously form nuclei in the form of aerosol dust with nanometer-sized particles, which are then collected in a dispersion medium or on a solid collector. Pre-mixed solutions of the starting materials make it possible to realize great versatility in synthesizing a wide variety of dust compounds with nanometer-sized particles with essentially uniform sizes and composition. By condensing the vapors of the burning liquid of the method, it is possible to obtain powders with nanometer-sized particles that are collected as colloidal dispersed systems, which are a convenient form for use and subsequent work. Preferred applications providing the benefits of producing such nanometer-sized powders include the manufacture of fine-shaped ceramics, powder coatings, and rheological fluids. Other applications of such high-quality, multicomponent powders with nanometer-sized particles include electronic, optical, magnetic, mechanical and catalytic applications. In a gas-phase chemical treatment, powders or powders with nanometer-sized particles can be introduced to react or act as catalysts. The use of an atomizer with condensing vapor of a burning liquid leads to simple and economical production processes to obtain a variety of the most advanced nanophase powders.

Another application of this atomizer is the latest atomizer to generate droplet dust with small droplets. The atomizer, using an innovative combination of simple, reliable components with moderate power requirements, allows for very fine atomization and evaporation of liquid solvents and fuels, as well as complete and fast atomization control. Such characteristics are necessary for introducing samples into the flame and for induction-excited plasma atomic spectroscopy, as explained above, as well as in many other similar important processes, including mass spectrometry and atomic emission spectrometry, drug delivery, analysis and fuel injection. In another chemical process application, hazardous materials can be more finely and uniformly separated in order to allow safer and more complete processing by fission using thermal energy, plasma, flame or other methods of reaction.

Spray drying technology is used to generate small particles. The atomizer allows for very fine atomization and evaporation of liquid solvents, as well as complete control of the degree of atomization. Such characteristics are useful in spray drying processes for the manufacture of pharmaceutical dry powders and the spraying of suspensions and mixtures for food and chemical products. The present invention can also provide more efficient production of polymer powders with precise particle sizes. Spray drying processes use the conversion of liquid to dry powder particles. This is achieved by spraying the fluid into the drying chamber, in which liquid droplets pass through a stream of hot air and are converted into solid particles by a mechanism controlled by local heat and mass transfer conditions. These particles are then collected and stored for future use. The main objective of the sprayer is to produce droplet dust with a high surface to mass ratio, droplets that can quickly and uniformly evaporate water or other solvents. This step in the spray drying process determines the primary size of the droplets and therefore significantly affects the quality of the produced powder. In applications such as protein delivery to the lungs, as well as peptide therapy, the drug should be delivered in the form of small particles in order to prevent exhalation or sedimentation in the upper respiratory tract. Other applications of the spray drying method using the atomizer according to the present invention include ceramic products and pressed powders for electronic technology, which play an important role in the industrial development of high-quality (state-of-the-art) ceramics. The ability to meet the requirements of particle size distributions, to produce a spherical shape of particles and to operate with abrasive raw materials for industry is an important reason for the widespread use of spray drying devices in ceramic industries. Spray drying devices for the chemical industries also produce a variety of powdery, granular, and agglomerated products in systems that minimize the generation of gaseous and liquid emissions, as well as particulate emissions. Highly efficient gas cleaning systems and high-quality bag filters prevent powder emissions, while processing systems eliminate solvent handling problems, product toxicity and flame explosion risks. Food products that exist in the form of a powder or agglomerate, such as coffee / coffee substitutes, food colors, maltodextrin, soup mixes, extracts of spices / herbs, tea, tomatoes, vegetable proteins, can be obtained by spray drying. Such an atomizer application is useful because the formation of these heat-sensitive products requires careful selection of the system and its operation in order to keep the highly nutritious product powders and high-quality powders accurate specifications.

The present invention also relates to spraying fuel for supply to combustion chambers in order to increase the burning of this fuel, thereby increasing fuel and heat efficiency, while reducing the amount of unburned hydrocarbon contaminants from combustion. The methods and apparatus described here are necessary when they are used to provide fuel atomization during the start-up and warm-up cycle during operation of the internal combustion engine, when fuel consumption and the production of environmental pollutants reaches the highest level (however, it should be understood that the invention is not limited to use any specific fuel or combustion chamber, but has a wide range of uses). Until a normal operating temperature is reached when the engine is already operating (a situation that is characteristic of all engines that must be started), internal surfaces of the engine having an ambient temperature (especially the inlet line) interferes with the process of vaporization of the fuel and even induces wetting of these surfaces. The non-vapor phase of the fuel does not burn, thus reducing the vaporization of the fuel leads to an increase in fuel consumption, as well as to the production of environmental pollutants (namely, unburned fuel), as well as to a decrease in the efficiency. By directing fuel through a small tube channel or chamber and quickly heating the fuel in the tube, the present invention provides thoroughly atomized heated fuel with droplets ranging in size from submicron to micron. Such highly atomized fuel burns out almost completely, reducing emissions during cold start and warming up to levels similar to those produced after the engine has reached operating temperature.

By providing heated, well atomized fuel, the fuel atomizer according to the present invention prevents wetting and lubrication in the fuel injector, throttle valve, inlet walls, valves, valve legs, valve seats, valve topography, cylinder wall, cylinder head, spark plug, spark plug thread, piston chamfers, piston clearances, piston ends, piston rings and other internal surfaces of the engine. The liquid fuel that collects on these surfaces not only increases fuel consumption by not being burned, but also acts as a heat sink, thereby preventing heat transfer to the engine and increasing the engine warm-up time. The atomizer heats the fuel by direct contact of the fuel with the heating element at the point of injection of fuel into the engine. The atomizer can be used to inject fuel at several different locations in the engine, or as an additional injector (i.e. a cold start injector), or as a primary fuel injector. Fuel can be supplied to the intake manifold, orifice, or directly to the combustion chamber, pre-chamber, or stratification chamber. In addition, the atomizer can be arranged to work in any combination of these locations, for example, as a central hole injector, or as a separate component of an injection system with multiple holes, or as a complete fuel supply system with flow rate control , or as an additional fuel injection system designed for cold start.

It should be noted that, while the examples and data presented here mainly relate to the combustion of gasoline in an internal combustion engine, the atomizer is fully adapted for use with any combustion device, as well as with other types of fuel. Examples of fuels include gasoline, diesel, kerosene, biofuels, heating oil or gas, fuels such as A1, JP-5 and JP-8. Examples of applications include two- and four-stroke internal combustion engines, furnaces, turbines, and heaters. There are an unlimited number of fuels and applications to which the present invention may be applicable, and therefore it is not necessary to limit the fuel atomizer to any specific application. In conclusion, the terms “combustion chamber” and “fuel” were used here to refer to any device that burns fuel and can provide the advantage of increased atomization of such fuel. However, one of the most beneficial uses of the fuel atomizer of the embodiments of the present invention is to reduce pollution emissions and fuel consumption during the start of the internal combustion engine; this application should be investigated first.

The nebulizer according to the present invention can be made in several different embodiments. In the main embodiment, the atomizer is a heated tube or chamber. A method of heating a tube may be selected from a variety of different methods, including, but not limited to: direct electric resistive heating (using a resistive tube or an internal heating element); heating by heat transfer (placing the tube in a block of material, and then heating the block with a cartridge heater) by passing heated fluid through or through the block, or other heating means); heating by radiation using laser, infrared, microwave radiation or other energy radiation source (s); hot gases or liquids (oil, water, glycol), a flame directed around the tube; or any combination of these and other known heating methods capable of providing the required temperature of the liquid. Electrical resistive heating is preferred because it provides a large range of controlled heating in a relatively small space. In a basic embodiment with electrically heated, a conductive / resistive tube or chamber is used. The term “tube” is intended to indicate a structural system having an internal surface area that is small compared to the length of the system. This can be better represented by introducing the ratio of length to characteristic internal width. The value of the characteristic internal width can be expressed as the square root for the average cross section of the inner area of the chamber. For example, a homogeneous square tube with sides of 3 mm would have an average cross-sectional area of 9 mm ² and a characteristic internal width of 3 mm. If this tube were 12 mm long, then the ratio of length to characteristic internal width would be 4. Although some systems may work with such a small ratio of length to characteristic internal width as 1, in most cases a length to a characteristic internal width ranging from 50 to 100. Higher ratios of the length to the characteristic internal width usually provide smaller and more uniform droplets. Ratios of even more than 1000 are preferred. At higher ratios of length to characteristic internal width, back pressure increases, which may be useful in some applications or limiting in others. In fact, for a specific application, the required internal cross-sectional area and length depend on the flow rate. For a flow rate of 25 ml / min, a certain ratio of about 100 can be expected. The exhaust manifold of the spray device includes one or more openings for supplying the spray liquid to the desired location, which depends on the specific use (smoke chamber, suction manifold, etc.). In embodiments with electric heating, the electrode is attached directly to the end of the device, and to the connecting joints or to any conductive object in electrical contact with a portion of the heating element of the atomizer. Voltage is applied through the electrodes, directing an electric current through the material around the chamber (or internal heating element) in order to thereby heat the material, which is in direct contact with the liquid inside the tube. When the liquid passes through the device, its temperature quickly rises to a level above the boiling point of the liquid under atmospheric pressure. However, since the liquid is maintained at elevated pressure, it remains in the liquid phase inside the heating chamber. The pumping pressure used to move the fluid through the device increases the boiling point of the liquid, thereby ensuring that the temperature is much higher than the boiling point of the liquid under atmospheric pressure. After exiting the device, the heated liquid is in a metastable state and it rapidly expands in the surrounding atmosphere or in a rarefied surrounding space. Such rapid expansion of the hot liquid results in extremely fine atomization of the liquid. The electrical power applied in this way can be adjusted to calibrate the heating of the tube so as to provide atomization for a specific fluid and / or application. In addition, such adjustment can be performed on the fly to allow controlled spraying of various liquids and / or combinations of liquids for which there are different spraying requirements, or to regulate the average particle size and size distribution required for a specific use. While the main embodiment illustrated here has a direct configuration with a circular cross section, in order to meet the requirements of use as well as spatial requirements, other forms of chambers can be used, for example, such as wound, bent, curved or others. Also not the tube or chamber is required to be round in cross section, it can be square, triangular, elliptical, etc. The spray can be made from a wide range of different materials, depending on the required resistance, strength, thermal characteristics, etc.

In addition to the main embodiment, several modifications are described below. A further embodiment has a tube or body that is made of a non-conductive material, such as ceramic or glass. The central heating wire or element extends along the longitudinal axis of the ceramic tube, thereby contacting and heating the liquid as it passes through the tube near the heating device. A ceramic tube provides electrical and thermal insulation for the heating element, and also provides structural strength for the heating wire or element. Other embodiments include a spirally twisted heating wire that extends along the inner surface of the chamber, from one end to the other, or within any portion of the interior space. This configuration provides additional surface area of the heating element per unit length of the chamber, which may be required at high flow rates or with increased heating. An advantage of a ceramic or insulated embodiment of the chamber is the ability to use a heating element in the form of a wire made of a more efficient, but still potentially less reliable material. In addition, the insulating material of the atomizer can be electrically, as well as thermally, insulating, thereby reducing the transfer of heat to the surrounding elements and increasing efficiency. As in the case of the first embodiment, the feed end of the ceramic pipe may include one or more fluid supply openings.

The above described embodiments may also include additional modifications designed to maximize the overall efficiency of the spray device and its specific use. Any of the aforementioned nebulizers may comprise a plurality, a group, or parallel tubes. Such tubes may have alternating sizes, shapes or cross sections depending on the requirements of the combustion chamber or other factors. For example, the tubes or chambers may have a successively decreasing diameter with the source tubes or wound chambers, and the end tubes with a direct configuration for directing fluid after leaving the spray gun. The specific combination of tubes having similar or different diameters, cross-sections, lengths, thicknesses, configurations (wound, bent, spiral, multi-tube twisted, etc.), as well as nozzle sizes, depend on the use.

Further modifications include the addition of materials to the outer surface of the atomizer. Such materials can be integrated with the main tube and be made in the form of an increased thickness of the tube, or they can be in the form of bushings or bushings made of various materials (such as materials with a positive coefficient of thermal expansion), covering, binding, or in some other way attached to the outer surface of the atomizer. The function of these materials can be any of the combinations: adding strength to the entire atomizer, acting as a heat sink or thermostat to stabilize the temperature, and / or thermal / electrical insulation. The overall shape and size of the atomizer can be optimized for specific use.

In order to make various elements of the liquid atomizer according to the present invention, many different materials can be used. The heating element (wire, pipe, etc.) can be any thermally / electrically conductive / resistive material that does not degrade under the influence of a liquid or the required heat and pressure. As is well known in the art, materials with a positive coefficient of thermal expansion can be used to maintain a specific temperature. In electric heated tube embodiments, stainless steel has shown satisfactory results in terms of electrical conductivity, heat transfer, strength and resistance to liquid. In embodiments with an electrically insulated tube, the tube may be made of any electrically insulating material that is not sensitive to the effects of the sprayed liquid. Heat loss can be minimized by using a thermal insulation material or air gap and / or increasing the wall thickness of the tube.

In order to control the temperature and pressure of the liquid, many methods for controlling the power of the atomizer can be used, thus changing the average droplet size, droplet size distribution and other specific application factors. In some applications, partial boiling of the liquid may be preferred. As the temperature of the liquid increases, the droplet size decreases, and the fraction of the gaseous and vaporous state of the liquid increases. Depending on the application, wt.% Of these stable gases and vapors can be 1, 5, 10, 20 or even reach 40% of the entire fluid leaving the chamber. The optimal thermodynamic state of the fluid exiting the nozzle (temperature and pressure) is selected based on the above factors. Spray level and fluid flow are properties that directly dictate the power requirements of the device. As in the known devices, the required power level is determined by a comparative analysis of the power input / output to the device and the spray level, which is determined by the average droplet size and uniformity for the type of liquid, as well as the heating method, the materials used to make the atomizer, and the heat transfer rate and other factors. The device can operate in a wide range of installed capacities. Setting very low power values results in medium atomization and droplets having sizes in the range of 20-100 microns. However, high power levels result in submicron atomization. As described above, the power setting can be adjusted during operation of the sprayer by simply changing the voltage applied to the sprayer material or the heating element. A power setting results in a specific maximum fluid temperature within the chamber (usually when the fluid exits the chamber). This maximum temperature may be maintained for a short time interval from fractions of a millisecond to 0.01 or 0.1 seconds, or may be maintained for one second, 10 seconds, or even one minute, depending on the properties of the liquid spray and the flow rate through the chamber. The pressure of the fluid entering the chamber is also controlled (by a pump located at the inlet or pressure regulator) in order to provide a specific pressure drop between the inlet and outlet of the chamber. Pressure drop 10 psi an inch may be adequate; however, a pressure drop of 50 psi may be required. inch, 100 psi inch or even 300 psi inch. In order to realize the required flow rate and the required back pressure, a change in the characteristic internal width, as well as the ratio of length to characteristic internal width, can be used. Some of the characteristics of liquid atomization, which determine the required temperature and pressure, include the relationship between the temperature and pressure of the liquid and gas (such as the boiling point), surface tension, viscosity, and the degree and size of any suspended solids that may be in the liquid .

Accordingly, the main objective of the invention is to provide a method of controlled spraying of liquid to obtain specific average droplet sizes and droplet size distributions depending on the particular use.

Brief Description of the Drawings

The invention is further explained in the description of specific variants of its embodiment with reference to the accompanying drawings, in which:

figure 1 shows a combined circuit diagram and a sectional view of a fluid supply system and an embodiment of a liquid atomizer, respectively, wherein a sectional view depicts details of an atomizer according to the present invention,

figure 2 shows a diagram of a drip dust supply system using the atomizer of the present invention,

3 is an isometric view of another embodiment of a liquid atomizer of the present invention,

4 is an isometric view of yet another embodiment of a liquid atomizer of the present invention,

figure 5 shows a vertical projection of the feed end of the spray liquid

figure 6 shows the results of laser Doppler velocity measurements obtained using a spray device for dispersing particles, according to the prior art,

Fig.7 shows the results of laser Doppler velocity measurements obtained using a spray device for dispersing particles according to the present invention,

on Fig shows the size distribution of droplets for alcohol at a flow rate of 4 ml / min for several levels of input power in the sprayer,

figure 9 shows the integral size distribution of droplets for alcohol at a flow rate of 4 ml / min for several levels of input power in the atomizer,

figure 10 shows the average size distribution of droplets for isopropyl alcohol at a flow rate of 4 ml / min for several levels of input power in the sprayer,

figure 11 shows the size distribution of droplets for spraying water near the edge of the droplet dust at a high level of spraying in various axial locations,

12 is a view showing a spray droplet dust produced using the atomizer of the present invention,

13 is a graph of hydrocarbon exhausts of an engine equipped with a spray gun operating at a low steady-state RPM under full load as a function of electrical power supplied to the fuel injector, as well as for comparing the graph of hydrocarbon exhausts from a modern well-known electronic fuel injection system.

Detailed Description of Preferred Embodiments

1, a general-type fluid supply system is generally indicated by a reference number 2. The supply system 2 includes a fluid source 6 that contains a supply fluid, the specific fluid used depends on the particular use. Through the fluid supply line 8, fluid is supplied to the inlet of the pump 12 through a filter 10 installed in front of the pump. The pump 12 delivers the liquid through a filter 14, installed after the pump, the control valve 16, the flow meter 18, and finally to the input 42 of the sprayer 4. The electronic control unit 3 receives the input signals from the flow meter 18, as well as other special feedback signals. Based on these feedback signals, the control unit 3 determines the appropriate power for supplying to the pump 12 and to the atomizer 4 in order to control both the liquid flow rate and the atomization level, as explained below. In addition, the control valve 16 can be electronically controlled so that the control unit 3 can control the pressure on the fly as soon as required.

A particularly effective embodiment of the liquid atomizer is shown in FIG. 1 under reference number 4. The liquid enters the atomizer 4 at the inlet 42 of the inlet 56 and is sent to the first end 48 of the ceramic or glass tube 44. Inside the ceramic tube 44 is a wound heating element 46, which passes along the length of the ceramic tube 44 (it should be noted that only part of the heating element 46 is shown). As the fluid flows down the tube 44, it progressively heats up to the desired temperature. The liquid exits the tube 44 at the other end 50 and is forced through a thin channel 52 located in the outlet block 54. When it enters the channel 52, the fluid pressure decreases due to friction losses in the channel 52, and when leaving the channel 52 at the outlet 58 the liquid rapidly drops to ambient pressure, thus spraying the liquid and producing a stream of finely divided drip dust. The inlet unit 56 and the outlet unit 54 are made of electrically conductive material and include channels 60 for inserting the ends of the heating element 46. The channel 60 may be only an internal blind channel so as to eliminate any leakage that still remains and to support the end of the wound heating element 46 in contact with the inlet and outlet blocks. A terminal 62 (shown here as a screw in a threaded hole, although other terminals can be used) connects electrical wires 64 and 66 to input 56 and output 54, respectively. It should be noted that although wire 64 is shown connected to ground and wire 66 is connected to control unit 3, other configurations can be used. For example, it may be necessary to attach a control wire to the inlet 56 and have a contact system with the outlet 54 that is directly earthed (for example, on the top of the engine in fuel injection applications).

A fuel supply system 70 using an atomizer according to the present invention is shown schematically in FIG. Fuel tank 72 provides a fuel storage tank (gasoline, diesel, JP-8 or other fuels) that is supplied to pump inlet 78 through fuel line 74 or fuel filter 76. The fuel pump 78 delivers fuel to a regulator 80, which returns excess fuel to the fuel tank 72 through the fuel return pipe 82. The fuel flow meter provides a signal indicative of fuel consumption for the atomizer 86. The control unit 88 supplies the atomizer with power based on the desired atomization level, type of fuel and other conditions. The flow meter may provide a signal to control unit 88 to compensate for fuel consumption. The atomizer delivers finely divided droplet dust 90 into the combustion chamber, the intake manifold or other places of the engine, depending on the specific application or type of engine. Although the pump 78 and the control unit 88, as shown, are supplied with a constant voltage of 12 V, it should be understood that other constant or alternating voltages can be used depending on the type of vehicle and the supplied voltages.

Figure 3 shows a detailed view of a simpler embodiment of the atomizer. This embodiment is essentially a hollow tube 25 (shown here with a circular cross section, although other shapes may be used) having a length L, an inner diameter D, a wall thickness T, an inlet end 27 and an outlet end 28. The tube 25 may be formed from any electrically conductive / resistive material whose temperature rises when an electric current passes through it. The actual material used depends on the full size of the atomizer, the type of liquid, heating requirements and other factors, although stainless steel was satisfactory. A pair of electrical wires 26 is connected to the tube 25 via electrical contacts 23 and 24, one at each end. The contacts 23 and 24 can be connected to the tube 25 by welding, soldering or in any other convenient way. As an integral part of the particle testing or particle production device, the outlet end 28 can contact the metal part of the device, so that a ground connection can be made at the outlet end of the tube 25. In this configuration, only one electrical connection 23 at the inlet end 27 is required. In another embodiment, both connections 23 and 24 are connected to the ground, and the central connection 37 provides a voltage potential. The central connection 37 can be located closer to the connection 24, thereby increasing the resistance between the connections 37 and 23 and at the same time reducing the resistance between the connections 37 and 24. This leads to a greater current flowing between the connections 37 and 24 and two levels of heating. When the liquid is heated to a higher level closer to the outlet end 28, the likelihood of wide boiling of the liquid in the tube decreases. The physical installation of the tube 25 can be achieved by means of internal or external threaded portions of the tube 25, pressing the tube, or by any other method that provides adequate strength, while ensuring free flow of fluid through the tube.

During operation, fluid enters the inlet end of the atomizer 20. Electric current passes through the atomizer tube 25, thereby heating the material of the tube, and also the liquid in the tube, which is in direct contact with the inner walls of the tube 25. As long as the liquid flows through the tube 25, it remains in liquid form, while its temperature increases. When exiting the outlet end of the tube 25, the fluid pressure rapidly decreases, resulting in a spray of fluid. The atomized liquid obtained in this way consists of extremely small droplets (of the order of several microns), and its temperature rises, which reduces the likelihood of condensation on the inner surfaces of the device under test. It should be noted that the temperature can be increased to a point where a two-phase flow (liquid and gas) can occur, or even at higher temperatures, the liquid can completely turn into steam, leading to a gas outlet. Although there may be applications in which this is desired, the main advantage of the nebulizer according to the present invention is its ability to control droplet size. This ability is lost as soon as the liquid has turned into steam, forming atoms or molecules of a particular material. Also, dissolved materials are more likely to settle on the tube at vaporization temperatures and change the fluid flow through the tube. A sleeve 29 of additional material may be installed along the entire length of the tube 25 or only along part of the tube 25. The sleeve 29 may simply add structural strength to the atomizer 20 or may provide electrical and / or thermal insulation between the atomizer 20 and other components of the device.

Figure 4 shows a further embodiment of the atomizer 30 according to the present invention. As in the main embodiment, the atomizer is in the form of a hollow tube 31 having an inlet end 32 and an outlet end 33. However, in this embodiment, the tube 31 is preferably made of a non-conductive material, such as, for example, ceramic. The centrally located heating element 35 extends along the central axis of the tube 31 (although in some configurations the heating element 35 may be offset from the center). Power is supplied to the heating element 35 through electrical wires 34 that are connected to each end of the heating element. Any end of the element 35 may be attached to a metal portion of the device to provide grounding. The ends of the heating element 35 may be supported by protrusions of the tube 31 itself or devices that support the tube 31. When the heating element 35 is placed inside the tube 31, the liquid completely surrounds the heating element 35, thereby increasing the efficiency of the heating element 35 compared to heating the entire tube that is in contact with liquid only inside. The tube 31 provides structural strength to the heating element 35, while isolating the heating element 35 from the electrically conductive elements of the device. 4 also shows an alternative heating means 98. The heating means 98 may include any number of radiating, conductive, or other heating means described above. Depending on the heating requirements, these heat sources 98 can be used in conjunction with or instead of the resistive heating means described above.

Figure 5 shows several holes for the outlet end for any of the above sprayer embodiments. Although for extremely small tube diameters the outlet end can be completely open, in the larger diameter tubes the outlet end is closed and includes a set of fluid supply openings 92, 94. In embodiments in which the tube is a heating element, making holes 92 along the outer portion of the outlet end 50 results in a temperature separation of the liquid, the liquid that is closest to the heating element, therefore, has a higher temperature than the liquid in the center of the tube. In some embodiments, one centrally located opening 94 can be made, while in other embodiments, the location, number and configuration of the holes can be adjusted to maximize atomizer efficiency. In applications in which the liquid comprises suspended particles, these openings 92 and 94 are made with diameters of at least twice the diameter of the particles to avoid clogging.

A commercially available atomization device of the prior art and a modern laser Doppler measurement system were used to measure the rate of air intake in the suction rotor of an automobile engine. Speed measurements were carried out in accordance with the position of the engine crankshaft. Within one minute, 78 measurements were performed. The results are shown in Fig.6, with each spot showing one of the 78 data points. These results show the inadequacy of using the prior art spray device for dispersion.

In a system with the same test configuration with laser Doppler measurement as for the prior art atomizer shown in FIG. 6, the atomizer according to the present invention was tested. The results are shown in Fig.7. Using a nebulizer according to the present invention as a dispersion device, 10,000 measurements were obtained over a one minute test period. Such an increased measurement number is indicative of a large number of particles of suitable size supplied to the air stream. Only particles of a suitable size reflect the laser light in such a way as to provide data measurements without affecting the air flow itself.

Droplet sizes were measured using organic solvents and using water. Measurements with organic solvents were performed using a Fraunhofer diffraction laser system (type Malvem Instruments Model 2600c), while a laser Doppler phase analyzer was used to simultaneously determine the distribution of droplet sizes and their velocity for experiments with water. On Fig shows that the distribution of droplet sizes can be controlled by adjusting the input power of the atomizer. For the experiments shown in Figs.

Also with respect to FIGS. 8-10, the following should be noted:

in Fig. 8, the vertical scale represents the volume, expressed in%, for particles of a certain size and

the horizontal scale represents the particle sizes in microns;

9, the vertical scale represents the volume, expressed in%, for all particles with sizes below a certain size, and

the horizontal scale represents the size of the particles in microns (for example, for an input power of 100% (40 watts) all particles smaller than 4 microns); and

10, a vertical scale represents the average droplet size in microns, and

horizontal scale represents input power in%.

This flexibility in droplet size selection is important in many applications, such as, for example, spray drying, particle coating, nanometer-sized powder production, and liquid fuel combustion. Extremely small droplets (most of which are in the submicron range, below the detection limit) can be created in the range of higher input powers of the atomization device. For a very low input power (20%), the droplet size distribution shows two distinct peaks (below 30 μm), followed by a wider peak with droplet sizes greater than 100 micrometers. When the power of the atomization device increases to 60%, the peaks shift towards smaller droplets and the main peak is centered in the vicinity of 4 μm. Under such operating conditions, more than 40% (volume) aerosol had droplet diameters of less than 4 micrometers (Fig. 9), despite the fact that no efforts were made to correct erroneous data obtained for droplet sizes below 1.2 μm . It was found that the size distribution of droplets shifts from large droplets (20-40 microns) for low input powers, to smaller droplets (2-10 microns) at moderate input powers. For higher input powers, most droplets are in the submicron range, and equipment like the Malvem Instruments Model 2600c was unable to properly register the droplet size distribution. The results presented here show that the aerosol obtained by the atomization device according to the present invention is distributed over a very narrow range of droplet sizes, and that at higher power levels, most droplets are in the submicron range (below the detection threshold of the instrument).

The average droplet size decreases with increasing input power; thus, sprayer performance can be optimized for varying flow rates and spray chamber requirements. The results show that the average droplet size decreases exponentially with increasing input power (FIG. 10). Measurements of the average droplet size for various solvent flow rates (1-5 ml / min) show that smaller primary droplets are obtained due to increased flow rate. Preliminary results show that the droplet size distribution is narrower than in the known pneumatic and ultrasonic atomizers. Even under suboptimal operating conditions, the droplet size distribution obtained using the atomizer of the present invention is limited to a few microns. 11 shows the size distribution of droplets for water at the highest setting of the atomizer mode (input power = 40 watts) on the center line of the droplet dust stream. The vertical scale is the particle count, while the horizontal scale is the droplet size in microns. It should be noted that for all axial positions, the distribution of droplet sizes is very narrow. The average droplet diameter is concentrated between 1 and 3 microns, and there are very few droplets larger than 5 microns. The Sauter average diameter (ratio of the third and second moment of droplet size distribution) increases from about 1 μm at an angle of 0.5 "from the nozzle to 2.5 μm at an angle of 1.5" from the nozzle.

The above described test results show that, in addition to the simple spray increase results achieved with the nebulizer according to the present invention, excellent control of the average droplet size and droplet size distribution can be realized. It is possible to vary the input power of the atomizer, as well as the flow rate of the fluid (liquids, suspensions, and combinations thereof) to achieve the results required for a particular application. As described previously, the size and number of nebulizers or openings of the nebulizer used may be adapted to a particular fluid or application. For example, in smoke chambers used for aerodynamic testing, a set of nebulizers can be used to show airflow along different sections of the test article. In smaller fluid flow tests, a single atomizer may be used. When the test flows vary from point to point, atomizers of various sizes in different positions can be used to provide the most efficient particle distributions. In the production of nanometer-sized powders, all parameters: size, flow rate, input power and outlet size can be adjusted to produce the average diameter of the powder and the desired size distribution.

The ability of various embodiments of the nebulizer according to the present invention to produce extremely small droplets is clearly illustrated by the photograph shown in Fig. 12. In order to show the sprayed liquid in contrast with the dark background, the sprayed stream of droplet dust exiting the sprayer was illuminated. In the right part of the photograph, the sprayed liquid dispersed before the appearance of “smoke”, which is especially useful in a number of the above applications.

The test of the main embodiment of the atomizer for use in fuel atomization was carried out using a fully equipped two-cylinder internal combustion engine with an upper clown connected to the engine traction meter. In order to simulate the heating of the engine, tap water was used to cool it during steady-state operation until the temperature of the water leaving the unit reached 20 ° C. Although warming up the engine is an unsteady process, the tests carried out are valid at some point in time during the warm-up cycle. In the test, a comparison was made between hydrocarbon exhausts for a standard injector and an atomizer for an engine operating at 1200 rpm with a relatively high load (19 lbfSft). The electrical power supplied to the atomizer tube varied in the range of approximately 90-215 watts. The test results can be seen in Fig.13. The vertical scale shows the hydrocarbon levels in parts per million (ppm), and the horizontal scale shows the atomizer input power in watts. For an electronic fuel injector, the measured hydrocarbon levels were 10,100 ppm. When a little more than 90 watts was supplied to the atomizer tube, the measured exhaust levels were approximately 8900 ppm. As the power supplied to the atomizer increased, hydrocarbon emissions decreased significantly up to an atomizer power of approximately 180 watts. At this point, measured hydrocarbon levels were approximately 7100 ppm, and did not decrease significantly when atomizer power was increased above 180 watts. It should be understood that this test was carried out in steady state on a slightly warm engine. However, the most significant reduction in hydrocarbon emissions can be expected during a substantially cold start of the engine in the first few minutes of its operation.

It should be understood that the terminology used here is intended only for the purpose of describing specific embodiments, but not for limitation. It should be noted that the singular numbers used in the description and in the claims include plural variations, unless the context clearly dictates otherwise.

Throughout the description, where publications are mentioned, the disclosures of these publications are incorporated by reference into the present description to more fully describe the state of the art to which the present invention relates.

Claims (23)

1. A method of spraying liquid, comprising the following steps: (a) providing a chamber having a first end and a second end; (b) directing the pressurized fluid into the first end of the chamber; (c) heating the liquid in the chamber; and (d) controlling the pressure and temperature of the liquid at the outlet of the chamber so that the average droplet size and size distribution of the droplets of the sprayed liquid are maintained within the desired range, with partial boiling occurring in the chamber. 2. The method according to claim 1, in which the liquid includes solid particles suspended in it, and the solid particles are dispersed by spraying the liquid. 3. The method according to claim 1, in which the average droplet size is less than 20 microns. 4. The method according to claim 1, wherein said step of providing a camera comprises providing a camera in which the second end of the camera is closed, and it includes many holes. 5. A method of spraying liquid, comprising the following steps: (a) providing a chamber having a first end and a second end; (b) directing the pressurized fluid into the first end of the chamber; (c) heating the liquid in the chamber; and (d) controlling the pressure and temperature of the liquid at the outlet of the chamber so that the average droplet size and size distribution of the droplets of the sprayed liquid are maintained within the required range in which the average size is 1 to 20 μm. 6. A method of spraying a liquid, comprising the following steps: (a) providing a chamber having a first end and a second end; (b) directing the pressurized fluid into the first end of the chamber; (c) heating the liquid in the chamber; and (d) controlling the pressure and temperature of the liquid at the outlet of the chamber so that the average droplet size and size distribution of the droplets of the sprayed liquid are maintained within the desired range, while the liquid is heated by passing an electric current through the material surrounding the chamber thus heating the liquid in the chamber. 7. A method for spraying liquid, comprising the following steps: (a) providing a chamber having a first end and a second end; (b) directing the pressurized fluid into the first end of the chamber; (c) heating the liquid in the chamber; and (d) controlling the pressure and temperature of the liquid at the outlet of the chamber so that the average droplet size and size distribution of the droplets of the sprayed liquid are maintained within the required range, while the liquid at the outlet of the chamber is in the form of liquid droplets, and also in the form of vapors and gases formed from the liquid, and stable gases and vapors at the outlet of the chamber consist of at least 1 wt.% of the sprayed liquid. 8. The method according to claim 7, in which the stable gases at the outlet of the chamber consist of at least 5 wt.% Of the sprayed liquid. 9. The method according to claim 7, in which stable gases and vapors located at the outlet of the chamber, consist of at least 20 wt.% Sprayed liquid. 10. A method of spraying a liquid, comprising the following steps: (a) providing a chamber having a first end and a second end; (b) directing the pressurized fluid into the first end of the chamber; (c) heating the liquid in the chamber; and (d) controlling the pressure and temperature of the liquid at the outlet of the chamber so that the average droplet size and size distribution of the droplets of the sprayed liquid are maintained within the required range, while the liquid at the first end of the chamber is under the first pressure, and at the outlet of the chamber, it is under a second pressure, the first pressure being at least 10 psi higher than the second pressure. 11. The method according to claim 10, in which the first pressure is higher than the second pressure by at least 50 psi. 12. The method according to claim 10, in which the liquid includes solid particles suspended in it, and these solid particles are dispersed by spraying the liquid. 13. The method according to claim 10, in which the second end of the chamber is closed, which includes many holes. 14. A method of spraying liquid, comprising the following steps: (a) providing a chamber having a first end and a second end; (b) directing the pressurized fluid into the first end of the chamber; (c) heating the liquid in the chamber; and (d) controlling the pressure and temperature of the liquid at the outlet of the chamber so that the average droplet size and size distribution of the droplets of the sprayed liquid are maintained within the required range, while the liquid at the outlet of the chamber has a certain temperature and the liquid inside The camera takes the same temperature or above this temperature for less than 1 min. 15. The method according to 14, in which the liquid at the outlet of the chamber has a certain temperature, and the liquid inside the chamber takes the same temperature or above this temperature in less than 0.01 s. 16. A device for spraying liquid, containing (a) a chamber having a first end and a second end; (b) means for heating the liquid in the chamber, in which the liquid is supplied under pressure to the first end and sprayed when it leaves the second end of the chamber, and (c) means for controlling the pressure and temperature of the liquid so that the average droplet size and size distribution droplets of sprayed liquid were maintained within the required range, while the means for heating the liquid includes a first electrical connection to the camera, a second electrical connection to the camera, spaced from the first electrical connection a source of electrical power, designed to provide voltage on electrical connections, and the voltage on the connections induces electric current through the material surrounding the chamber, thereby heating the fluid inside the chamber. 17. A device for spraying a liquid containing (a) a chamber having a first end and a second end; (b) means for heating the liquid in the chamber, in which the liquid is supplied under pressure to the first end and sprayed when it leaves the second end of the chamber, and (c) means for controlling the pressure and temperature of the liquid so that the average droplet size and size distribution droplets of sprayed liquid were maintained within the required range, while the liquid at the first end of the chamber was under the first pressure, and at the outlet of the chamber was under a second pressure, the first pressure being higher than the second pressure, at least e, at 10 lb / sq. inch. 18. The device according to 17, in which the second end of the chamber is closed and includes many holes that allow fluid to exit from the second end of the chamber. 19. A method of spraying fuel, comprising the following steps: (a) providing a chamber having a first end and a second end, as well as a ratio of length to characteristic internal width of at least 10; (b) directing the pressurized liquid into the first end of the chamber; and (c) directly heating the fuel in the chamber, the fuel being sprayed when it leaves the second end of the chamber. 20. The method according to claim 19, in which the camera has a ratio of length to a characteristic internal width of at least 20. 21. The method according to claim 19, in which the camera has a ratio of length to a characteristic internal width of at least 50. 22. A fuel atomization device comprising (a) a chamber having a first end and a second end and a ratio of length to a characteristic internal width of more than 10; and (b) means for directly heating the fuel in the chamber, wherein the fuel is supplied under pressure to the first end and sprayed when it comes out of the second end of the camera. 23. The device according to item 22, in which the second end of the chamber is closed and includes many holes that provide fuel exit from the second end of the chamber.

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