Abstract:
The invention relates to a method and a device for generating a nanoaerosol, wherein at least one fluid to be atomized is atomized in a nozzle via a nozzle opening of the nozzle along a discharge direction in the form of fluid particles, the atomized fluid particles are deflected from the discharge direction and larger fluid particles are at least partially separated from smaller fluid particles, the separated larger fluid particles are returned to the fluid to be atomized and the smaller fluid particles are dispensed onto the environment. A cartridge in which the nozzle and the fluid to be atomized are arranged is used. According to the invention, a stream of a carrier gas is generated in the nozzle and at least one fluid to be atomized is brought into contact with the carrier gas.

Description:
TECHNICAL FIELD 
     The present invention relates to a method and to a device for generating a nanoaerosol by atomizing fluids, in particular to a method and to a device for generating a nanoaerosol, especially a nanoaerosol for therapeutic, diagnostic or disinfection purposes. 
     BACKGROUND 
     It is well known that liquid disinfection agents can be sprayed as finely divided droplets, for example to disinfect items or air of a room contaminated with harmful aerosols. In addition, the beneficial effects of vapors or aerosol mists consisting of finely divided water or oil droplets have also long been known. In conventional sauna or steam baths, water or an aqueous emulsion containing a small amount of essential oils is evaporated. The hot steam cools down in the sauna cabinet and condenses to form mist droplets. A disadvantage of generating mist by evaporating water or an aqueous oil emulsion lies in the high temperature of the generated mist. While the stimulating effect of the hot mist can be vital for certain applications, conventional sauna and steam baths still suffer from the disadvantage that the circulation of the bather is severely challenged, and thus saunas and steam baths are contra-indicated for many groups of people. Thus, it has been suggested that aqueous solutions or emulsions be atomized at lower temperatures, typically at temperatures below 35° C. or 40° C., preferably at temperatures in a temperature range of 22-28° C. The stress on the circulation of the person to be treated would be reduced compared with conventional sauna or steam baths. 
     In the international patent application WO 00/44331 A1 a whole body mist bath device and a method for administering a whole body mist bath are described, wherein a mist bath is generated at temperatures below 35° C. To this end, a liquid is compressed to a pressure of more than 100 bar and then expelled through a nozzle in an explosive manner into a treatment cabinet so that on being expelled into the cabinet, the liquid is atomized into many small droplets of liquid due to its high internal pressure. In WO 00/4433 A1 it has already been proposed that aqueous salt solutions or oils with vitamin supplements or essential additives could be used to generate a mist. If a mist is to be produced from two different liquids, according to WO 00/44331, two separate nebulizers are used. In the nebulizers described in that document, a compression volume in the form of a hollow cylinder with a closable opening is provided which is connected via a line to a high pressure pump which delivers the liquid to be nebulized. 
     In the international patent application WO 2009/087053 A1 a method and a device for atomizing fluids is described, in particular for generating a therapeutically effective aerosol in a treatment area, wherein an aerosol generator is used which pressurizes the fluid to be atomized and which expels it at a flow rate in the range 50-300 m/s through at least one discharge opening in the form of small particles into a treatment area. In one embodiment of the device described in WO 2009/087053, the fluid to be atomized is disposed in a cartridge that comprises at least one discharge opening for atomizing fluid and a movable piston that can be moved by means of a drive means. The movable piston exerts a pressure on the fluid in the cartridge such that the fluid is dispensed through the discharge opening at the required flow rate of 50-300 m/s in the form of a finely divided mist of liquid. 
     One of the disadvantages of the known devices described above, however, is that the particles of liquid are generated with a relatively broad size distribution. Typically, the aerosol mist contains a mixture of particles with a diameter from a few nanometers to several micrometers. However, many applications for aerosols require and desire particle sizes in the sub-micrometer range. If in such cases particles are also dispensed with larger diameters, this results in an unnecessary loss of fluid that is not effectively put to use, which is a particular disadvantage when the fluid contains an active substance. 
     SUMMARY 
     Hence, the technical problem underlying the present invention is to provide a method and a device for generating a nanoaerosol wherein fluid particles essentially with a particle diameter of less than 1000 nanometers are produced. The corresponding device in this case should be simple and cheap to manufacture and operate, and in particular be able to atomize fluids containing active substances in a sterile manner. 
     This technical problem is solved by the cartridge for generating a nanoaerosol and an aerosol generator in accordance with the independent claims. Further advantageous embodiments are defined by the subject matter of the dependent claims. 
     Thus, the invention relates to a method for generating a nanoaerosol, wherein at least one fluid to be atomized is atomized in a nozzle via a nozzle opening of the nozzle along a discharge direction in the form of fluid particles, the atomized fluid particles are deflected from the original discharge direction, and larger fluid particles are at least partially separated from smaller fluid particles, and the separated larger fluid particles are returned to the fluid to be atomized, and the smaller fluid particles are dispensed onto the environment. The concept behind the invention is that atomization of a fluid by expelling the fluid from a nozzle necessarily produces fluid particles with a relatively broad distribution of sizes. Instead of dispensing the generated fluid particles directly into the environment, it is proposed that the atomized fluid particles be initially deflected out of the discharge direction so that the larger fluid particles can be separated from the smaller fluid particles. In the method according to the invention, the fluid particles which are eventually dispensed into the environment have a greatly reduced proportion of larger particles, and preferably essentially only smaller fluid particles. Thus, the method of the invention can be used to generate smaller fluid particles in a desired size range, while larger fluid particles are returned to the fluid to be atomized so that loss of fluid to be atomized by dispensing fluid particles in an unwanted size range can be avoided and the fluid to be atomized can be atomized essentially entirely in the form of fluid particles in the desired size range. The desired size range for the dispensed small fluid particles can in particular be adjusted and optimized by modifying the rheological properties of the fluid to be atomized and the operating parameters and the geometry of the atomizing device. 
     In the method according to the invention, a cartridge is preferably employed in which the nozzle and the fluid to be atomized are disposed. The cartridge, which will be described below in more detail, may be a reusable cartridge; particularly preferably, it is a disposable cartridge. 
     The fluid can be expelled from the nozzle in various manners. As an example, a movable piston may be provided which forces the fluid to the nozzle opening. In contrast to the cartridge described in WO 2009/087053 A1, for example, in this case the piston would not expel all of the fluid in a single stroke, since in the context of the present invention, larger fluid particles are returned to the fluid to be atomized. Rather, each stroke would only expel a portion of the fluid so that a piston operating periodically over several cycles would atomize all of the fluid to be atomized including the larger particles returned during each cycle. However, such a variant is not very effective having regard to the separation of larger and smaller fluid particles, since in the absence of further measures, the smaller fluid particles would be dispensed into the environment passively by diffusion. In addition, a mechanically actuated piston is a common source of faults when operating the device. 
     In a particularly preferred variant, a movable piston is not used and a stream of a carrier gas is generated in the nozzle and brings the at least one fluid to be atomized into contact with the carrier gas. The fluid is thus driven out of the nozzle by means of the carrier gas and atomized into fluid particles. The carrier gas also acts to dispense the smaller fluid particles into the environment. 
     The nozzle is thus preferably constructed such that the fluid to be atomized is drawn up and atomized by means of an underpressure generated in the nozzle. This underpressure can be generated by the carrier gas flowing out of the nozzle in an application of the known Venturi principle. 
     Particularly preferably, a hermetically sealed cartridge is used, so that the method of the invention is particularly suited to dispensing sterile fluids which contain active substances and are stored in the cartridge. Prior to use, openings are made in the cartridge to allow the carrier gas to be fed in and the atomized smaller fluid particles to be dispensed into the environment. Depending on the purpose and the fluid used, however, sealable or open cartridges may be used, which means that, for example, they can be refilled while in operation; this may be advantageous when a lot of fluid is used, for example when disinfecting air. 
     In accordance with a particularly simple embodiment of the method according to the invention, the larger fluid particles are returned to the fluid to be atomized under gravity, while the smaller fluid particles are dispensed into the environment in a direction that differs from the direction of gravitational pull, for example vertically upwards. In this regard, for example, discharge openings may be provided in the upper region of the cartridge from which the carrier gas can escape, entraining the smaller fluid particles. 
     The fluid to be atomized preferably comprises at least one active substance. The active substance can, for example, be selected from the group formed by active substances consisting of disinfecting agents, deodorizing agents, fragrances, cosmetics and diagnostic and/or therapeutic agents for the treatment of living beings. Examples of typical active substances are pharmaceuticals, hyaluronans, vitamins, acidifying agents or vegetable or synthetic oils. Furthermore, substances that modify the immune system, for example with paramunity-inducing substances, may also be used as active substances. Examples of substances suitable for disinfecting the air are oxidative substances such as percarbonic acid. The fluid to be atomized may be an aqueous solution, an aqueous emulsion, in particular an oil-in-water emulsion, an oily solution, an oily emulsion, in particular a water-in-oil emulsion, an aqueous suspension or an oily suspension. A particularly preferred aqueous solution is a salt solution. A particularly preferred oily solution is a solution which comprises essential oils. The fluid to be atomized may also comprise special active substance preparations typically in the form of negatively charged lipid vesicles with the active substance in the core of a lipid shell or in the lipid shell itself. 
     The therapeutically effective agents for the treatment of living beings, for example, in the case of the topical application of the generated nanoaerosol, may include drugs for the treatment of skin diseases or, in the case of inhalation of aerosol, may include drugs for treating diseases of the airways. Agents for the treatment of general illnesses and agents for enhancing well-being, for example substances familiar to the wellness industry, may also be used. 
     The atomized smaller particles which are dispensed into the environment may, for example, be dispensed onto the items to be treated with a stationary or portable device (for example in the case of a disinfection procedure). Particularly preferably, however, the atomized smaller particles are dispensed into a treatment area. The treatment area in this case may be any area that is suitable for the application in hand which, for example, can allow the skin or airway of a person to be treated or an animal to be treated to come into contact with the atomized nanoaerosol particles. In this respect, the treatment area may, for example, also be an inhalation mask. Preferably, however, the treatment area is a treatment chamber, which partially or completely surrounds the living being to be treated with the nanoaerosol. 
     In a preferred variant of the method of the invention, at least a portion of the smaller fluid particles to be dispensed are electrostatically charged. If the object or living being to be treated is earthed or is connected to an opposite potential, treatment can be particularly effective since in this case the smaller fluid particles to be dispensed are attracted by the object or living being to be treated. 
     In accordance with the invention, the smaller fluid particles have a diameter of less than 1000 nanometer, preferably a diameter of 5-750 nm, in particular 5-300 nm, and particularly preferably a diameter of 10-300 nm, in particular 10-200 nm. By matching the rheological properties of the fluid to be atomized, optimizing the nozzle and the pressure and/or the throughput of the carrier gas, the mean diameter of the smaller fluid particles that are delivered can be adjusted to a certain extent. Since the dispensed aerosol mist contains practically no fluid particles with a diameter of more than one micrometer, when used for inhalation purposes, for example, practically all of the particles generated gain ready access to the lungs. For disinfection applications, using a nanoaerosol means that no film of moisture is deposited on the objects to be disinfected, so that to a certain extent “dry” disinfection is made possible. Harmful agents present in suspended droplets can be attacked by collisions with the fluid particles generated in accordance with the invention resulting, for example, in a reduction in the pH or oxidation in the droplets containing the harmful agents. 
     The invention also relates to a cartridge for generating a nanoaerosol, having at least one reservoir for the fluid to be atomized, a demixing chamber which comprises a deflection device and at least one discharge opening for the fluid to be atomized, a nozzle which has at least one nozzle opening leading into the demixing chamber and at least one channel from the reservoir, which opens into the nozzle. The nozzle opening is preferably disposed on a longitudinal axis of the nozzle; the deflection device is disposed in the extension of the axis. 
     Preferably, there is a communicating connection between the reservoir and the demixing chamber so that a portion of the deflected fluid particles, in particular fluid particles with a larger diameter, can return from the demixing chamber to the reservoir. 
     As mentioned above, in a particularly preferred embodiment, the nozzle operates with a carrier gas. Thus, at least one supply line which opens into the nozzle is provided for a carrier gas. 
     In a variant of the cartridge of the invention, the supply line for the carrier gas is formed as a central bore which leads at one end into the base of the cartridge and its other end merges into the nozzle. 
     In order to form a hermetically sealed cartridge, the bore opening in the base of the cartridge is sealed by a pierceable wall. In this case, the at least one discharge opening for the fluid to be atomized is also preferably sealed by a pierceable or tear-open wall. As an example, one or more tear tabs may be disposed on the top of the cartridge by means of which openings can be formed in the top. 
     In a preferred variant of the cartridge of the invention, the nozzle is formed as a Venturi nozzle. 
     The cartridge may also comprise means for connecting the reservoir with an electrical voltage supply source. In a variant, in which the cartridge is exclusively formed from an electrically non-conductive material, for example from a non-conductive plastic material, these means may, for example, consist of a pierceable, initially sealed opening in the base of the cartridge through which, prior to using the cartridge, an electrode connected to the electrical voltage supply source is introduced into the cartridge in such a manner that the electrode comes into contact with the fluid to be atomized. In a further variant, the nozzle may consist at least in part of an electrically conductive material and means may be provided for connecting the nozzle with an electrical voltage supply source. 
     In accordance with a preferred embodiment, the cartridge consists of at least two components which can be connected together after filling with the fluid to be atomized. Connection of the two components may, for example, be by means of a plug and socket type connection, screw type connection or the like. Particularly preferably, the connection is constructed in such a manner that after filling with the fluid to be atomized, the two components are connected such that a user cannot disconnect them. As an example, the two components may be bonded or welded. In this case, the fluid to be atomized can be hermetically sealed in the cartridge so that until it is put to use, it is guaranteed that no contamination can enter the cartridge from outside, thereby ensuring that the fluid contained therein is sterile, for example. 
     In the cartridge sealed in this manner therefore the fluid to be atomized is contained. 
     Subject of the invention is also an aerosol generator comprising a mounting to accommodate at least one cartridge as hereinbefore described and means for expelling the fluid contained in the fluid in the form of a nanoaerosol. 
     Preferably, the means for expelling the fluid contained in the cartridge comprises a source of a carrier gas, wherein the mounting has at least one first hollow spike which communicates with the source of the carrier gas and can penetrate into the supply line for the carrier gas of the cartridge, and at least one second hollow spike which communicates with the environment and can penetrate into the discharge opening for the fluid of the cartridge to be atomized. Prior to expelling the fluid, the first hollow spike and the second hollow spike are mechanically, for example hydraulically or pneumatically, driven into the hermetically sealed cartridge. Instead of the second hollow spike for opening the discharge opening of the cartridge, the cartridge itself may be provided with appropriate tear tabs which are arranged such that on moving the cartridge in the mounting, one or more discharge openings are exposed. The tear tabs may, for example, be disposed on the top of the cartridge such that when the cartridge is moved in the mounting, they snap off and form one or more openings on the top of the cartridge which communicate with the demixing chamber of the cartridge. 
     The source of the carrier gas may, for example, be a compressor or a compressed gas bottle which preferably contains an inert gas. 
     In accordance with a further preferred embodiment, the aerosol generator also comprises an electrical voltage supply source which can be connected with the cartridge, for example in the form of an electrode that can be driven into the cartridge. 
     The invention also relates to a mist bath device with a bath or treatment area to accommodate at least one living being to be treated or parts of the body of a living being to be treated, wherein the mist bath device is characterized in that it comprises at least one aerosol generator of the type described above. The mist bath device may, for example, be an aerosol cabinet as described in international patent applications WO 00/44331 A1 and WO 2009/087053 A1. 
     Preferably, the mist bath device also comprises means for earthing the living being or parts of its body to be treated or to charge it electrostatically with the opposite sign to the liquid to be atomized. In addition, deposition of the charged nanoparticles on the body or parts of the body of the living being may be enhanced by means of an externally applied electromagnetic field. 
     Finally, the present invention relates to a use of the cartridge of the invention for the therapeutic treatment of living beings, wherein the nanoaerosol which is generated is taken up via the lungs, skin or in the form of a whole body inhalation. 
     Typical quantities of liquid atomized in the context of a treatment depend on the dimensions of the treatment area in which the aerosol mist is to be generated. When handling parts of a person&#39;s body, liquid quantities of a few milliliters are amply sufficient. When treating a person in a mist bath device accommodating the whole person, typically 1 to 25, preferably 1-20 ml of liquid is atomized, whereas when treating large animals, for example horses in appropriate stalls or cubicles, up to 100 ml of liquid per treatment can be atomized. The dimensions of the cartridge of the invention are each matched to the quantity of liquid to be atomized. Alternatively, the required quantity of liquid can be atomized by means of several cartridges either one after the other or simultaneously. The principle of the cartridge of the invention, however, does not limit it to a specific volume. Substantially larger volumes of fluid than those mentioned above are also possible. Thus, for example, when disinfecting the air of large areas over a long time period, for example an aircraft cabin during an intercontinental flight, much larger cartridges may be used. Variants may also be envisaged wherein the cartridge of the invention can be refilled or recharged. The cartridge may, for example, have a refilling opening or be connected via a refill line to a storage vessel for the fluid to be atomized. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will now be described in more detail with reference to the accompanying drawings. In the drawing: 
         FIG. 1  shows a mist bath device suitable for carrying out the method according to the invention; 
         FIG. 2  shows a schematic diagram of the principle of one embodiment of the aerosol generator according to the invention; 
         FIG. 3  shows a preferred embodiment of the cartridge of the invention in side view; 
         FIG. 4  shows a base view of the cartridge of  FIG. 3 ; 
         FIG. 5  shows a top view of the cartridge of  FIG. 3 ; 
         FIG. 6  shows a longitudinal axial section through the cartridge of  FIG. 3  along the line VI-VI of  FIG. 5 ; 
         FIG. 7  shows a detailed enlargement of the section of  FIG. 6 ; 
         FIG. 8  shows a longitudinal axial section of the cartridge of  FIG. 3  along the line VIII-VIII in  FIG. 5 ; 
         FIG. 9  shows an enlarged detailed view of the section of  FIG. 8 ; 
         FIG. 10  shows a variant of the upper part of the cartridge of  FIG. 3 ; 
         FIG. 11  shows a top view of the variant of the upper part of  FIG. 10 ; 
         FIG. 12  shows a first variant of the tear tab of  FIG. 10 ; 
         FIG. 13  shows a second variant of the tear tab of  FIG. 10 ; and 
         FIG. 14  shows a variant of the drive for the cartridge housing of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a mist bath device with the general reference numeral  10  as has been described, for example, in international patent applications WO 00/44331 A1 and WO 2009/087053 A1. The mist bath device  10  is spatially defined by a base panel  11 , a top panel  12 , side screens  13  formed from acrylic glass and two front screens  14 ,  15  which are movable in the directions of arrows A, B and which provide access to the treatment chamber  10 . A pipe  16  in the mist bath device  10  extends between the base panel  11  and the top panel  12 . In addition, a waterproof bench seat  17  is disposed above the base panel  11 . Instead of the means for generating an aerosol described in WO 00/44331 A1 and WO 2009/087053 A1, in the pipe  16  the mist bath device  10  has an aerosol generator in accordance with the invention which will be described in more detail below. The aerosol which is generated can flow via a grille  18  disposed in the pipe  16  into the treatment area  19 . 
     If, as will be described below in more detail, the aerosol particles generated are electrostatically charged, the bench seat  17  can be earthed or oppositely charged. When the person to be treated sits on the bench seat, the aerosol particles in the treatment area  19  will be attracted by the person to be treated. Correspondingly, for example, the side walls  13  of the mist bath device  10  may, for example, be formed from a conductive material which, after the treatment is completed, is oppositely charged to the aerosol particles. The rest of the aerosol particles in the treatment area are then attracted to the side walls and can then be readily wiped away. Alternatively or in addition, a blower (not shown in  FIG. 1 ) may be provided which draws the remaining aerosol particles from the treatment area  19  after the treatment. This ensures that even the sub-micrometer aerosols produced with the aerosol generator of the invention can be effectively removed from the treatment area  19  before the mist bath device is used again. 
       FIG. 2  diagrammatically shows an aerosol generator according to the invention, with general reference numeral  20 , which may be used in the mist bath device  10  of  FIG. 1 . The aerosol generator  20  has a mounting  21  for an exchangeable cartridge which contains the fluid to be atomized. In the example shown, the mounting  21  has a fixed upper part  22  and a movable lower part  23 , which is connected to a pneumatic drive  24 . The mounting  21  and the pneumatic drive  24  may, for example, be disposed in the pipe  16  of the mist bath device  10  of  FIG. 1 . The pneumatic drive  24  is connected to a compressor  25  which, for example, may be disposed under the bench seat  17  of the mist bath device  10 . Two compressed air lines  26 ,  27  are pressurized alternately and lead from the compressor to the pneumatic drive in order to move the piston  28  to and fro. The piston  28  is connected with the movable lower part  23  of the mounting  21  via a piston shaft  29 . A central hollow spike  30  is disposed in the mounting  23  and is also connected to the compressor  25 , via a line  31 , and can be pressurized with compressed air. Further, in the movable lower part  23  of the mounting  21 , a metal tip  32  is disposed which is connected via an electrical cable  33  with one pole  34  of a low current supply  35 . The other pole  36  of the low current supply  35  may, for example, be connected with a metal plate  37  set into the seat  17  of the mist bath device  10  of  FIG. 1 . In the embodiment shown, the fixed upper part  22  of the mounting  21  has a central guide spike  38  and hollow spikes  39  disposed in a circle around the guide spike  38 . 
     An initially hermetically sealed cartridge  40 , which will be described in more detail in connection with  FIGS. 3-13 , is inserted in the mounting  21 . Fluid  41  to be atomized is in the cartridge  40 . The pneumatic drive  24  compresses the cartridge  40  between the upper part  22  and the lower part  23  of the mounting  21  such that the hollow spike  30  and the metal tip  32  can penetrate the base  42  of the cartridge  40 , while the spikes  39  pierce the top  43  of the cartridge. The guide spike  38  in this case penetrates into a depression  44  provided in the top of the cartridge  40 . In order to generate the nanoaerosol, compressed air is blown into the cartridge  40  via the hollow spike  30 . The compressed air and smaller aerosol particles in the sub-micrometer range leave the cartridge  40  via the hollow spikes  39  and enter the environment from the top  45  of the upper part  22  of the mounting  21 . In order to prevent deposition of aerosol particles on the upper part  22  of the mounting  21 , the upper part  22  can be connected to the same pole  34  of the electrical supply  35  which is also connected to the metal tip  32  which acts as an electrode so that the upper part  22  and the aerosol particles generated develop the same charge. 
       FIG. 3  is a first variant of the cartridge  40  according to the invention in a diagrammatic side view. The outer housing of the cartridge  40  consists of two injection molded parts  47 ,  48  which can be connected together after filling with the fluid to be atomized in a manner, for example by bonding or ultrasound welding, such that a user cannot separate them. In the sealed condition shown in  FIG. 3 , the fluid to be atomized is hermetically sealed in the cartridge  40 . The lower part  48  of the cartridge  40  has a protruding lug  49  to assist in correctly inserting the cartridge in the mounting  21  of the aerosol generator of  FIG. 2 . In the example shown, the cartridge is approximately 55 mm high, with a diameter of approximately 30 mm. Several milliliters of a fluid can be dispensed into the mist bath device of  FIG. 1  using such a cartridge. 
       FIG. 4  shows the base  42  of the cartridge  40  of  FIG. 3 . The base  42  has a central opening into which a stopper  50  is inserted. The hollow spike  41  can penetrate into the stopper and bore through its base  51  and thus penetrate into the interior of the cartridge  40 . Further, a plurality of rings  52  are formed thereon; their floors  53  are also sealed. One of the floors  53  of the rings  52  may, for example, be pierced by the spike  32  acting as an electrode. 
       FIG. 5  shows a top view of the cartridge  40  of  FIG. 3 . It can be seen that the top  43  of the upper part  47  of the cartridge  40  is formed as a ring which borders the depression  44  into which the guide spike  38  of the mounting  21  of the aerosol generator  20  can penetrate. The hollow spikes  39  of the mounting  21  are preferably disposed such that when the spikes penetrate into the top  43 , evenly distributed openings in the ring  43  are introduced into the top of the cartridge  40 . 
       FIG. 6  shows a longitudinal section of the cartridge  40  of  FIG. 3  along the plane defined by line VI-VI of  FIG. 5 . It can be seen that the cartridge has a central bore  54  which extends from the base  51  of the central ring  50  and leads into a nozzle tip  55 .  FIG. 7  is an enlarged view of the nozzle tip  55  circled at VII in  FIG. 6 . 
     The bore  54  acts as a supply line for the carrier gas which is blown into the nozzle  55 . The nozzle tip  55  is formed as a Venturi nozzle so that the carrier gas passing through the nozzle can draw in the fluid to be atomized from a reservoir  56  of the cartridge  40 . The nozzle  55  consists of an outer shell  57  which in the present case is formed together with the lower part  48  as a single injection molded part. An inner shell  58  representing a separate injection molded part is inserted through the base  42  of the cartridge into the outer shell when manufacturing the cartridge such that an annular channel  59  is left between the inner shell and the outer shell which communicates with the reservoir  56  and via which the fluid  41  to be atomized can be drawn into the nozzle tip  55 . To keep the annular channel  59  open even when the central bore  54  is pressurized, a plurality of ribs  60  may be provided on the top side of the inner shell  58  or on the underside of the outer shell  57  to act as spacers (see  FIG. 7  in particular). The carrier gas flowing out from the opening  61  of the inner shell  58  through the opening  62  of the outer shell  57  results in an underpressure in the annular gap  59  which draws the fluid to be atomized out of the reservoir  56  towards the opening  62 . The angle of the opening  62  of the outer shell  57  in the example shown is approximately 32°. The diameter of the opening  61  in the example of  FIGS. 3 to 9  is approximately 0.6 mm and the diameter of the opening  62  at the narrowest point is 0.9 mm. If the supply line  54  is pressurized with a carrier gas pressure of approximately 2 bar, fluid particles in the sub-micrometer range and fluid particles with diameters of more than 1 μm are produced on leaving the nozzle tip  55 . In order to separate the larger from the smaller fluid particles, a demixing chamber  63  is provided in the cartridge in the transitional region between the upper part  47  and the lower part  48 . The demixing chamber  43  comprises a deflection device  64 , which has a die  65  which in the assembled condition of the cartridge is positioned approximately 2 mm above the nozzle opening  62 . Within the limits of the set angle of the nozzle opening  62 , the mixture of larger and smaller fluid particles leaving the nozzle  62  is expelled essentially axially upwards out of the nozzle  62  and impinges immediately directly on the deflection device  64 . The fluid particles are thus deflected sideways so that larger fluid particles can flow under gravity back into the fluid reservoir  56 , while smaller fluid particles in the sub-micrometer range are carried out through openings  66  which are formed by the spikes  39  of the mounting  21  in the top  43  of the cartridge  40 . With the cartridge according to the invention, it can thus be ensured that the fluid  41  in the cartridge is essentially dispensed completely in the form of a nanoaerosol into the environment. In order to be able to use up the last drops of fluid, the base  67  of the fluid reservoir  56  is inclined towards the gap  68  at the bottom of the channel  59 . 
       FIG. 8  shows a longitudinal section of the cartridge  40  of  FIG. 3  in the plane defined by the line VIII-VIII. Inwardly directed ribs to reinforce the cartridge lie in this plane. 
       FIG. 9  shows the bottom region of the inner shell  58  and outer shell  57  enclosed in the circle in  FIG. 8  with the gap  68  formed at the bottom of the channel  59  formed between the inner shell and the outer shell shown in more detail. 
       FIG. 10  shows a variant  47 ′ of the upper part  47  of the cartridge  40  in  FIG. 3 . In this case, the upper part  47 ′ has tear tabs  69 ′ on its top  43 ′ which are formed as one piece with the upper part  47 ′. When the tear tabs  69 ′ are snapped off, they expose openings in their bottom region  70 ′ formed in the top  43 ′ of the upper part  47 ′, through which the nanoaerosol can escape from the cartridge. In order to guarantee snapping off of the tear tabs  69 ′, the upper part  22  of the mounting  21  of  FIG. 2  has no spikes  39  but may, for example, have a slightly tapered inner surface which pushes the tear tabs inwards when the pneumatic drive  24  pushes the cartridge into the upper part  22  via the movable lower part  23  of the mounting  21 . Thus, the upper part  22  of the mounting is particularly easy to clean. 
       FIG. 11  shows a top view of the upper part  47 ′ of  FIG. 10 . 
       FIG. 12  shows a variant  69 ″ of the tear tabs  69 ′ of  FIG. 10 . In the example shown, the tear tabs  69 ″ differ from the triangular tear tabs  69 ′ of  FIG. 10  in that they have a recess  71 ″ at one side. In order to form an opening  70 ″ in the top of the upper part  47 ″ of  FIG. 12 , the tear tabs  69 ″ are not bent inwards, but are pushed downwards in the plane of  FIG. 12 . The tear tabs  69 ″ thus essentially turn about a corner point  72 ″ into the configuration of the tear tab shown in dashed lines in  FIG. 12 , whereupon an opening  70 ″ in the surface  43 ″ is exposed. 
       FIG. 13  shows a further variant  69 ′″ of the tear tab  69 ′″ of  FIG. 10 . The tear tab  69 ′″ of  FIG. 13  is essentially rectangular and has a rounded upper edge  74 ′″. Thus, the upper part  22  of the mounting  21  ( FIG. 2 ) can be formed as a hollow cylinder, making cleaning thereof even simpler. 
     Finally,  FIG. 14  diagrammatically shows a less expensive variant  24 ′″ of the cartridge drive  24  of the aerosol generator of  FIG. 2 . The aerosol generator essentially corresponds to the aerosol generator  20  of  FIG. 2 ; for the sake of clarity, therefore, not all of its components are shown. The aerosol generator again has a mounting  21  for a replaceable cartridge  40  which contains the fluid to be atomized. Instead of a pneumatic drive (reference numeral  24  in  FIG. 2 ) to drive the spikes into the cartridge, in the variant of  FIG. 14 , a purely mechanical drive  24 ′ is provided. The cartridge  40  is placed on an upper cradle  81  which is movably mounted in the mounting  21 . The central hollow spike  30  described in  FIG. 2  is positioned on a movable lower cradle  82 . In the example shown, the lower cradle  82  is moved upwards by means of a manually actuatable toggle lever  83  so that on the one hand the spike  30  is stabbed into the base of the cartridge  40  and on the other hand the upper cradle  81  with the cartridge  40  is forced against the upper part  22  (not shown in  FIG. 14 ) of the mounting. To this end, the toggle lever  83  has an actuating arm  84  that can be operated by the user. The upper part  22 , not shown, has spikes the form of which depend on the embodiment of the cartridge  40  to produce the discharge openings in the cartridge (comparable to the spikes  38  in  FIG. 2 ) or only an appropriate counter ring to snap off the tear tabs of the cartridge  40 . The compressor  25  (not shown in  FIG. 14 ) is then no longer responsible for the drive, but only for generating compressed air which is blown through the hollow spike  30  into the cartridge  40 . Clearly, in this variant, an electrode (not shown here but analogous to electrode  32  in  FIG. 2 ) may be inserted into the cartridge in order to charge the fluid electrostatically.