EP0663241B1 - Spray nozzle - Google Patents

Abstract

Jet system, has assembly (1) with a laying surface (11) and a channel (13) to feed the medication at the centre of the laying surface (11), extending along the longitudinal line of a jet assembly (1). The holder (2) for the jet assembly (1) has a holding surface (21) to take the laying surface (11) of the jet assembly (1). Groove channels (22) are in the holding surface (21) to feed a pressurised gas, aligned radially to the base shape of the jet holder (2). The channel (13) for the medication and the channels (22) for the gas open into a mixing chamber (23). The cross section surface generally equals the sum of the cross section surfaces of the channels (22) for the gas at their openings.

Description

The present invention relates to an atomizing nozzle for Inhalation with which a powdery or liquid Atomizing material, preferably in the form of a solution or Suspension is atomized.

On atomizing nozzles for the production of an aerosol for Therapeutic purposes are subject to increased demands. The therapeutic quality of the Aerosols; then an aerosol is to be generated, which is a as large a proportion of respirable particles as possible (⊘ <8 µm) contains. In addition, the atomizer nozzle must be simple and residue can be cleaned, which leads to the fact that Atomizer nozzle can be dismantled without great difficulty got to. Despite numerous different designs, there are two Groups of atomizer nozzles based on different Principles work.

A first group of atomizing nozzles works after the Venturi principle. A nozzle of this type is for example known from DE 32 38 149 A1. Through a central Compressed gas duct is supplied with compressed air, which in a Mouth level emerges from an opening in the central channel. In addition to the compressed gas duct, there are usually several intake ducts provided that from the mouth level to a container for the atomizing material is sufficient. The atomization material is from the escaping compressed gas is sucked in through the intake ducts and emerges from openings of the intake ducts in the mouth plane. The openings of the compressed gas duct and the intake ducts are arranged adjacent, so that there is compressed gas and atomization mix intensively and the turbulence that occurs for to provide atomization. With atomizer nozzles of this type aerosols are generated, the primary distribution of which is aerosol particles with a diameter of up to 40 µm. For this The reason for this is that the drying of the Aerosols caused by a sufficiently large amount of air ensures post-treatment of the aerosol required; this includes, for example, separation large particles from the aerosol through constructive measures. The separated atomization material is placed in the container returned and can be atomized again. In some Cases is the circulation of the atomized material unproblematic. However, numerous medications are suitable for this type of atomization not or only poorly, since with a Impaired effectiveness of the drug must become. Furthermore, a comparatively large amount of Atomizing material is provided to suck the Allow atomizing material through the intake channels. In addition, excessive amounts remain in the atomizer, because the atomization material is never completely complete due to the design can be consumed. Add to that the through Concentration of solvent due to solvent evaporation Drug associated with a change in physical Properties of the solution, as well as the direct or indirectly influenced negative influence on the Drug delivery. Some very expensive drugs are being made for these reasons not in the context of inhalation therapy applied, although the medication for this type of Application are quite suitable.

Another group of atomizing nozzles are air and Atomizing material under pressure, i.e. actively fed. Atomizer nozzles of this type are made, for example DE 26 46 251 A1 and DE 28 23 643 A1 are known. The basic one The structure of atomizer nozzles in this group also results from "Atomization and Sprays" by Arthur H. Lefebvre. Differentiate become characteristic designs in this context based on the type and location of what is occurring Atomization process, on the one hand so-called "air-assist" nozzles with mixture inside or outside the Nozzle body and so-called "prefilming" nozzles. This Atomizer nozzles follow a common design principle insofar as circular channels around a central channel are arranged concentrically. This leads to a complex Structure and sometimes considerable dead spaces within the Nozzle body. The atomizer nozzles are for this reason only to dismantle conditionally or only with great effort. For example, the nozzle body consists of DE 26 46 251 A1 known atomizer nozzle made of six elements, five of which have a central opening to which the elements refer must be aligned so that the openings are coaxial are arranged. The atomizing nozzle, which is a "prefilming" nozzle is suitable because of the Orientation of items related issues not for repeated disassembly and cleaning. It also has known atomizer nozzle has a considerable dead space, since the thin liquid film generating gap space from a very much larger annular space is all around what also applies to the nozzle known from DE 28 23 643 A1. This But construction is required to get through the gap Feed atomization material so that a thin liquid film enters the central gas flow on all sides.

Based on the prior art, the invention is the Task based on an atomizer nozzle for inhalation purposes create an aerosol with the largest possible proportion respirable particles can be generated and still easy to handle, especially disassemble and clean, as well as simple and inexpensive to manufacture (mass-produced items).

This task is solved by an atomizing nozzle with the Claim 1 specified features. An atomizer nozzle with the features of the generic term this Claim is known from document DE-U-91 115 96. More beneficial Refinements result from the subclaims.

Fig. 1

eine perspektivische und eine geschnittene Darstellung des Düseneinsatzes einer erfindungsgemäßen Zerstäuberdüse;

Fgi. 2

eine perspektivische und eine geschnittene Darstellung der Düsenaufnahme einer erfindungsgemäßen Zerstäuberdüse;

Fig. 3

die weiteren Bestandteile eines Ausführungsbeispiels einer erfindungsgemäßen Zerstäuberdüse;

Fig. 4

das Ausführungsbeispiel einer erfindungsgemäßen Zerstäuberdüse aus Fig. 3 in zusammengesetztem Zustand; und

Fig. 5

ein weiteres Ausführungsbeispiel der erfindungsgemäßen Zerstäuberdüse mit einem totraumminimierten Zerstäubungsgutanschluß.

The invention is described in more detail below with the aid of a preferred exemplary embodiment and with reference to the accompanying drawings. In the drawings:

Fig. 1

a perspective and a sectional view of the nozzle insert of an atomizing nozzle according to the invention;

Fgi. 2nd

a perspective and a sectional view of the nozzle receptacle of an atomizing nozzle according to the invention;

Fig. 3

the further components of an embodiment of an atomizer nozzle according to the invention;

Fig. 4

the embodiment of an atomizer nozzle according to the invention from Figure 3 in the assembled state. and

Fig. 5

a further embodiment of the atomizer nozzle according to the invention with a nebulized atomization material connection.

In the embodiment described below there is the atomizer nozzle according to the invention from several parts, which in Fig. 3 are shown. The design of the Nozzle body, which consists of two parts, the nozzle insert 1 and the Nozzle holder 2 exists.

In Fig. 1 the nozzle insert is shown; Figure A shows the nozzle insert 1 in a perspective view, Figure B in a sectional view. The basic shape of the nozzle insert 1 is composed of two flat circular cylinders with different diameters and a circular cone, the maximum diameter of which corresponds to that of the smaller circular cylinder. The circular cone defines a contact surface 11 of the nozzle insert 1. The two circular cylinders and the circular cone are arranged axially to one another. The larger circular cylinder is flattened on its circumference at two opposite points 12, only one of which is visible in FIG. 1A. A channel 13 for the atomizing material is provided centrally in the nozzle insert 1 and extends in the longitudinal direction of the basic shape of the nozzle insert 1, so that the outlet opening 14 lies in the tip of the support surface 11. The outlet opening 14 defines the smallest diameter d of the channel 13 and thus its outlet cross-sectional area A _Z ; the channel 13 has a gradually increasing diameter.

FIGS. 2A and 2B show the nozzle holder 2 in a perspective or sectional representation. The basic shape of the nozzle holder is formed by two flat circular cylinders which are arranged axially to each other. The free end face of the larger circular cylinder has a central circular conical depression which defines a receiving surface 21 which is adapted to the shape of the bearing surface 11 of the nozzle insert 1. In the receiving surface 21, three channels 22 for the compressed gas are formed, which run radially to the center of the flat circular cylinder and thereby follow the inclined receiving surface 21 of the circular-conical depression. The channels 22 are evenly distributed over the circumference of the nozzle receptacle 2, so that there is an angle of 120 ° between them, and taper towards the center of the nozzle receptacle. The channels 22 for the compressed gas are grooves in the receiving surface 21 with a rectangular or trapezoidal cross-section and with a minimal cross-sectional area A _D at the mouth end.

The channels 22 for the compressed gas end in a cylindrical Mixing chamber 23 which is coaxial with the flat circular cylinders of the Nozzle holder 2 runs. On the of the deepening on the opposite side, the mouth space 23 opens a circular conical outlet funnel 24.

3 shows, in addition to the nozzle insert 1 and the nozzle holder 2 further parts of the embodiment of the invention Atomizer nozzle shown. A cylindrical housing 3 is used to accommodate the nozzle body, i.e. of the nozzle insert 1 and the nozzle holder 2 in the order shown in Fig. 3. Of the Inner diameter of the housing 3 corresponds to the diameter of the each larger, flat circular cylinder of the two Nozzle body forming parts 1 and 2 by a complete open end face of the housing 3 in its interior can be introduced. The opposite face of the housing 3 only has an opening 31 for receiving the smaller, flat circular cylinder of the nozzle holder 2. Inside on the end face of the housing surrounding the opening 31 3 is a circular groove 32 for receiving an O-ring 33 intended. There is also a groove 34 for receiving another O-rings 35 on the open for receiving the nozzle body End face of the housing 3 is provided in the housing wall. On this side, an external thread 36 is formed on the housing 3.

A cover 4 serves on the one hand to close the housing 3 and on the other hand has connections for the supply of Atomizing material and the compressed gas. The cover 4 has a cylindrical basic shape with an axially arranged Bore 41 for the supply of the atomizing material and one eccentrically arranged bore 42 for the supply of Compressed air. A section of the cover 4 has one Diameter that is sufficient to interact with the O-ring 35 to seal the interior of the housing 3. At that Nozzle insert 1 facing side of the cover 4 are two flat Circular cylinder with a smaller diameter provided; in the The surface of the smaller circular cylinder is a circular groove 43 designed to receive an O-ring 44. The bigger the Both diameters serve to guide the cover 4 in the housing 3. The three O-rings 33, 35, 44 are complete Separation of the gas and liquid part within the nozzle.

A union nut 5 is used to secure the housing 3 used parts and points to an inner Circumferential surface a thread 51. In the opposite An opening 52 is provided on the end face, which provides access to the connection holes 41 and 42 in the cover 4 guaranteed.

Fig. 4 shows the embodiment of the invention Atomizer nozzle in assembled condition. The nozzle body, i.e. the nozzle insert 1 and the nozzle holder 2 are in the housing 3 arranged. The circular conical bearing surface 11 of the Nozzle insert 1 lies on the complementarily shaped Receiving surface 21 of the nozzle receptacle 2. Over the lid 4, the union nut 5 and the housing 3 are the two Parts forming the nozzle body are braced against each other, resulting in a good fit of the nozzle insert in the nozzle holder and one Alignment of the outlet opening 14 with respect to the Mixing chamber 23 guaranteed. The as grooves in the Receiving surface 21 formed channels 22 are on their originally opened top through the contact surface 11 of the nozzle insert 1 closed. The by the eccentric Connection bore 42 in the cover 4 supplied compressed air by the 12 at the flattened points Nozzle insert 1 in the housing 3 resulting space 6 in the annular space 7, which is the flat circular cylinder with smaller Diameter of the nozzle insert 1 forms around. Flows from there the compressed air through the three channels 22 into the mixing chamber 23.

5 shows a further exemplary embodiment of the Atomizer nozzle according to the invention in the assembled state. The structure corresponds in many points to that described above Embodiment, so that reference to its description can be taken. The following are the differences explained by which the two embodiments award.

The nozzle insert 1 has the one shown in FIG Embodiment for the atomization material with a channel 13 one except for a section in the area of the outlet opening 14 constant diameter. This diameter is chosen that a flattened cannula is inserted and thereby the dead space can be minimized. The smallest spout For cleaning reasons, diameter d is as short as possible held.

In the cover 4, the axial bore 41 is designed so that a Rubber disc 43 with a central hole for the cannula 8 can be inserted. Above this is an intermediate ring 44 arranged on the side of the rubber washer 43 inwards slightly conical, preferably at an angle of 160 ° is trained. With the help of an axially receiving the cannula Pressure screw 45, the cannula after the complete Push into channel 13 by tightening the pressure screw locked and sealed against the environment.

The diameter of the mixing chamber 23 is such that you free cross section about the sum of the free cross sections of the Channels 22 for the compressed gas at the outlet into the mixing chamber 23 results in the energy of the compressed air supplied optimally to take advantage of. If the cross-section of the mixing chamber 23 is too large it leads to premature relaxation if the cross-section is too small to congestion of the compressed air. The goal is an optimized one Exploitation of the implementation of the pressure difference between compressed gas and ambient pressure in the kinetic energy range Outlet openings of the channels 22. A crucial role plays the distance between the channel 13 escaping liquid and the outlet openings of the channels 22 for the compressed air. The length of the mixing chamber corresponds to about their diameter. A mixing chamber that was too short would regarding the required channel depth in the mouth area manufacturing difficulties. With one too long mixing chamber can worsen the Atomization efficiency through impaction and friction, as well as for Tendency to constipation come.

On the basis of these considerations, it was found that the following proportions according to the invention are to be observed. The cross-sectional area A _{M of} the mixing chamber 23 essentially corresponds to the sum of the minimum cross-sectional areas A _{D of} the channels 22. The smallest diameter d of the channel 13 for the atomizing material at the outlet opening 14 is approximately 55% to 85%, preferably 60% to 70% of the Diameter D of the mixing chamber 23.

To the one hand by tightening the nozzle insert and Nozzle holder against each other a secure fit and one Self-centering of the two parts forming the nozzle body guarantee and on the other hand the energy output of the compressed air to the atomization material supplied through the channel 13 favor, the angle of the circular tapered bearing surface 11 or the complementary receiving surface 21 about 120 ° be. Smaller angles than 120 ° do not only affect unfavorable in this connection, but also lead to Problems with the manufacture and cleaning of the nozzle body (Degree formation at the outlet in the nozzle insert at the Injection molding, risk of damage to the edge of the hole in the Nozzle insert, poor access to the mixing chamber the cleaning).

The channels 22 for the compressed air can be different than in the case of The exemplary embodiment described also in the contact surface 11 of the nozzle insert 1 are formed. However, the one above described configuration to be preferred because of the risk of mechanical damage to the channels, especially in the area the mixing chamber 23 is reduced. That too is Cross-sectional shape of the channels 22 for the compressed air not to one rectangular shape or the shape of an isosceles Limited trapezes. With a view to simple Injection molding are the cross-sectional shapes described advantageous and are also particularly suitable in With regard to the reduction in cross section to the middle of the Nozzle body out to accelerate the compressed air under Serves to increase the kinetic energy.

In the described embodiment of the invention Atomizer nozzle are three channels 22 for the compressed air in the Receiving surface 21 is provided. With an approximately square Cross section of the air duct 22 in the region of the mouth into the Mixing chamber 23 is the influence of manufacturing deviations the smallest cross-sectional size. The channel depth should be about correspond to half the mixing chamber length. From geometrical Considerations and in terms of possible Manufacturing accuracy in injection molding seems the number of three channels for the supply of compressed air be. An odd number of channels for the compressed air, stabilized and in particular three channels in 120 ° arrangement centers the outflowing aerosol after exiting the Atomizer nozzle. A tangential can also support this Arrangement of the channels 22 based on the mixing chamber 23 act. This appears due to technical considerations Design to be difficult to implement. To a flat design of the channels 22 is also preferred for the compressed air, since this means that not only cleaning Channels but also the mixing chamber is simplified. The channel 13 for the atomization material in the nozzle insert 1 can with a Wire or nylon cord.

Since there by the supply of compressed air into the mixing chamber 23 If there is overpressure, the atomization material must pass through the channel 13 are added under pressure in the nozzle insert 1. Thereby offers the possibility of the ratio of mass flows to vary over the amount of atomization material supplied. Practically any amount of the atomizing material be atomized as a much larger amount (> 250 µl / min) than the sensible amount of up to for therapeutic purposes 50 µl / min can be supplied. With an air flow of 4.5 to 5 l / min and a pressure difference of 2 bar therapeutically useful amount also dried off easily will. This removes particles from the primary aerosol with a Diameters of up to 16 µm due to drying alone greatly reduced that by the atomizer nozzle according to the invention an aerosol is generated without further aftertreatment Contains 100% respirable particles.

The advantages of the atomizing nozzle according to the invention lie in the simple manufacturability (mass article), simple construction (easy cleaning), in the dosage option of Liquid phase (different recipes), fine Primary droplet spectrum (relatively high initial concentration of Drug solution possible, i.e. short inhalation times) and low pneumatic power requirement (Δp <2 bar, Air volume flow <5 l / min, i.e. Compressor operation possible, Home therapy).

The following are the results of investigations shown on differently designed atomizing nozzles were carried out with the structure according to the invention.

It should first be noted that the air flow rate of the examined atomizer nozzles with the pressure difference and the Bore the nozzle holder, i.e. the diameter of the mixing chamber 23 rises. Starting from a nozzle insert 1 with a Exit opening 14 of 0.30 mm (d 0.30), combined with one Nozzle holder 2 with a mixing chamber 23 of 0.40 mm Diameter (D 0.40), takes the mean drop diameter increasing mixing chamber diameter at constant pressure first off, go through a minimum and then pick up easy to close again. The optimum results from the combination d 0.30 / D 0.45. This behavior can be seen from the Energy ratios in the mixing chamber 23 are explained.

The duct dimensions are the same for all three nozzle holders. The liquid flows through a constant volume flow Bore of 0.30 mm diameter in the mixing chamber 23 promoted. With a mixing chamber diameter D of 0.40 mm their free cross-section is smaller than the sum of the free ones Cross sections of channels 22 at the mixing chamber inlet. It comes to The compressed air in the mixing chamber 23 larger diameter of the mixing chamber 23, about 0.50 mm Distance between the channel mouth and the liquid hole 14 larger than with a smaller mixing chamber diameter. The Compressed air can relax too early. In both cases, one too small or too large mixing chamber diameter D, the Delivery of the kinetic energy of the compressed air to the liquid negatively affected and thus the dispersion efficiency worse.

When applying the average droplet diameter over of pneumatic performance, which as the product of Pressure difference Δp and the air flow V is defined, have both nozzle bodies, d 0.30 / D 0.45 and d 0.30 / D 0.40 about the same power efficiency. The Primary droplet spectrum needs one to dry defined amount of dispersing air. The nozzle body 0.30 / DK 0.45 is therefore more suitable, because with it a constant Liquid flow in a spray with a certain mean Droplet diameter with more air flow and lower Pressure difference is dispersed.

The dispersion efficiency of the nozzle body is d 0.30 / D 0.45 independent of liquid flows up to 250 µl / min. In the Mixing chamber prevail due to the air jet deflection and Air jet acceleration determined an operating point corresponding shear forces. These shear forces act Surfaces on the liquid droplets. The Surface force depends on the drop diameter. One certain shear force corresponds to a certain one Drop diameter, below which the drop is no further can be crushed. To disperse the liquid a certain amount of compressed air, the amount of liquid appropriate proportion of energy taken. The rest is used for Transportation or dissipated. With larger liquid flows the compressed air can release more dispersing energy. Because of the drying required is only smaller, from Air flow dependent liquid flows make sense.

The selection of the operating point of a nozzle can be based on the Application of the product from the average drop diameter and the air flow rate over the pressure difference. This criterion also serves to select a suitable one Compressor for home therapy. The optimal operating point corresponds to the minimum in the course of this function. Of the Liquid flow and drug concentration then have to be adapted to the air flow at the operating point. For short Inhalation times are high fluid flows with high Drug concentration necessary, the high air flow rates and require finer primary droplet distributions. The nozzle will operated at higher pressures than the determined energetic Optimum corresponds.

Claims (14)

1. Atomiser nozzle for atomising a powdered or liquid atomisation product, preferably in the form of a solution or suspension, for inhalation therapy, with a nozzle body consisting of

   a nozzle insert (1) with

   -- a supporting surface (11) and

   -- a channel (13) for supply of the atomisation product, which is arranged at the centre of the supporting surface (11) and which extends in the longitudinal direction of the basic shape of the nozzle insert (1),

   and

   a nozzle receptacle (2) for receiving the nozzle insert (1) with

   -- a receiving surface (21) on which rests the supporting surface (11) of the nozzle insert (1),

   -- channels (22) for the supply of a compressed gas which extend essentially radially to the basic shape of the nozzle receptacle (2), and

   -- a circular cylindrical mixing chamber (23) into which open the channel (13) for the atomisation product and the channels (22) for the compressed gas,

   characterised in that

   the channels (22) for the compressed gas are formed in the receiving surface (21) of the nozzle receptacle (2) in the form of grooves and open into the mixing chamber (23) through the peripheral surface thereof, and

   the sum of the minimum cross-sectional areas A_D of the channels (22) for the compressed gas in the opening region essentially corresponds to the cross-sectional area A_M of the mixing chamber (23).
2. Atomiser nozzle according to claim 1, characterised in that the mixing chamber (23) is circular cylindrical.
3. Atomiser nozzle according to claim 2, characterised in that the diameter D of the mixing chamber (23) is approximately equal to its length.
4. Atomiser nozzle according to any of the preceding claims, characterised in that the channels (22) for the compressed gas in the nozzle receptacle (2) have a rectangular or trapezoidal cross-section.
5. Atomiser nozzle according to claim 4, characterised in that the channels (22) have a trapezoidal cross-section and the side walls of the trapezoidal channels (22) for the compressed gas are inclined at an angle of 3° to 15° to a side wall perpendicular to the bottom of the channels.
6. Atomiser nozzle according to any of the preceding claims, characterised in that the channels (22) for the compressed gas have a cross-section tapering towards the mixing chamber (23).
7. Atomiser nozzle according to any of the preceding claims, characterised in that the diameter d of the outlet opening of the channel (13) for the atomisation product corresponds to about 55% to 85% of the diameter D of the mixing chamber (23).
8. Atomiser nozzle according to any of the preceding claims, characterised in that the diameter d of the outlet opening of the channel (13) for the atomisation product corresponds to about 60% to 70% of the diameter D of the mixing chamber (23).
9. Atomiser nozzle according to any of the preceding claims, characterised in that the diameter d of the outlet opening of the channel (13) is equal to 0.3 mm and the diameter D of the mixing chamber (23) is equal to 0.48 mm.
10. Atomiser nozzle according to any of the preceding claims, characterised in that the nozzle insert (1) and the nozzle receptacle (2) have a circular cylindrical basic shape, the supporting surface (11) and the receiving surface (21) are circular conical, and three channels (22) offset by 120° along the circumference are provided in the receiving surface (21).
11. Atomiser nozzle according to claim 10, characterised in that the nozzle insert (1) is constructed from two flat circular cylinders of different diameter and a circular cone, which are arranged coaxially with each other, so that after reception of the nozzle insert (1) in a cylindrical housing (3) in the region of the smaller circular cylinder is formed an annular gap (7) through which the compressed air is supplied to the channels (22) of the nozzle receptacle (2).
12. Atomiser nozzle according to claim 11, characterised in that the larger circular cylinder of the nozzle insert (11) at the circumference comprises flattened portions (12) in the region of which in the housing (3) is fixed a gap (6) through which the compressed air is supplied to the annular gap (7).
13. Atomiser device according to any of the preceding claims, characterised in that the supporting surface (11) of the nozzle insert (1) and the receiving surface (21) of the nozzle receptacle (2) are circular conical.
14. Atomiser device according to claim 13, characterised in that the circular cone has an angle in the range from 100° to 140°, preferably 120°.

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