Device for spraying media on the inner sides of medical products

Abstract

The invention relates to a device (10) for spraying or applying a medium using an auxiliary gas in the form of compressed air or a pressurized inert gas, more particularly to the inner sides of medical products or vessels, said device having a binary nozzle (1) formed from at least two cannulae (2, 3) which are inserted into each other and have a substantially constant diameter over the longitudinal extent thereof, having a nozzle body (4) which is designed as a holder for the binary nozzle (1) and has at least one inlet (11, 12) each for the medium and for compressed air or an inert gas, wherein clamping inserts (5, 6) adapted to receptacles (7, 8) are arranged on the nozzle body (4) to sealingly hold and fix an internal cannula (2) and an external cannula (3), wherein the clamping inserts (5, 6) are provided for securing the cannulae (2, 3) inserted into each other with the formation of a predefined gap (14) between the inner cannula (2) and the outer cannula (3).

Description

[0001] The present invention relates to a device for spraying or applying, for example, liquid media to surfaces using compressed air or a pressurized gas, particularly in the case of medical products, such as the inner surfaces of medical containers or the like. In medical technology, automated systems are required for various medical products, by means of which media must be applied to the inner surfaces of the products, such as pipettes, syringes, or glass containers like test tubes. For example, in certain medical products, the inner surface of such containers is coated in automated systems with media in the form of, for example, water-soluble agents or suspensions such as heparin, BCA, or EDTA before they can be further processed to complete the product.

[0002] A problem with previously known devices for spraying or applying media within such containers or medical products is that the media are often unevenly distributed on the surface because precise dosing in confined spaces is difficult. According to the known principle of a conventional two-fluid nozzle, the liquid (medium) is carried along by compressed air with turbulent flow as it exits the nozzle and distributed as droplets on the surface of the container. However, a problem with these known two-fluid nozzles is that, given the relatively limited space inside the containers, the nozzles are often too large, forcing the exiting compressed air to flow out again at higher flow velocities.This faster flow of compressed air causes already wetted droplets to be carried away from the wall of the container, thus destroying or irregularizing the coating with the medium.

[0003] Furthermore, a problem exists in that achieving uniform media distribution and an adjustable spray pattern within the surfaces of such medical products was not easily accomplished with existing devices or automation systems. Finally, spraying different media, such as liquids, was also problematic, as the inner areas of the medical device surfaces to be treated often have a relatively small diameter, preventing conventional two-component nozzles from being inserted.

[0004] WO 2009 / 153040 A1 describes a coating device intended to enable a uniform distribution of atomized fluid on the inside of a hollow body by improving the atomization of the fluid. For this purpose, an atomizing tube and a hollow needle form a Venturi arrangement, wherein the dispensing opening of the hollow needle is located in a region with the narrowest cross-section of the atomizing tube, or the hollow needle forms this narrowest cross-section together with the atomizing tube.

[0005] Against this background, the object of the present invention is to provide a device for spraying or applying media under compressed air or compressed gas supply, particularly on the inner surfaces of medical products or vessels, which enables the most precise and accurate distribution of the medium to be applied and in which the spray area within the inner surfaces of such products or vessels can be precisely adjusted. Furthermore, the object of the present invention is to provide a device with the simplest possible design for such applications in the medical field for spraying media, which also allows for the rapid exchange of the media to be applied and the spray nozzles to be used.

[0006] This problem is solved by a device having the features of claim 1. Advantageous embodiments and further developments of the invention are the subject of the dependent claims.

[0007] According to the present invention, a device for spraying or applying a medium under compressed air supply or by means of another auxiliary gas, such as z.13.Inert gas under pressure, proposed, which is particularly designed and adapted for spraying or applying the media to the inner surfaces of medical products or narrow vessels and which has a two-component nozzle made of at least two nested cannulas with substantially the same diameter over their longitudinal extent, with a nozzle body designed as a holder for the two-component nozzle, which has at least one inlet each for a medium and for the auxiliary gas, wherein the device is characterized by a nozzle body which has receptacles and clamping inserts adapted to the receptacles for a sealed holder and fixation of an inner cannula and an outer cannula, for example in the form of hollow needles, wherein the clamping inserts on the nozzle body are provided for fastening the nested cannulas with the formation of a predefined gap between the inner cannula and the outer cannula.According to the invention, a device is provided which essentially consists of two cannulas in the form of an inner cannula and an outer cannula, which are held and fixed in a nozzle body, namely a central holding element. The two cannulas, nested one inside the other, are each held and fixed in the nozzle body by means of clamping inserts. The inner and outer cannulas are nested together in such a way that an annular gap with predefined dimensions is formed between them, through which compressed air or another auxiliary gas can flow outwards while a medium simultaneously flows out through the inner cannula. This form of a two-fluid nozzle with two nested cannulas minimizes the influence of the reduced velocity of the outgoing compressed air. The reduced airflow velocity prevents droplets already applied to the inner walls of the vessels from being carried away and removed.The corresponding recesses in the nozzle body are designed so that the respective nested cannulas can be inserted and securely sealed using the clamping inserts. The clamping inserts have the advantage of ensuring automatic centering and sealing of the respective compressed air and medium supply areas.

[0008] The two nested cannulas have a substantially constant diameter and thus a constant cross-section along their longitudinal extent, at least in the direction of the ejection end of the device. This means that the two cannulas, namely the inner cannula and the outer cannula, are each formed from a simple, thin tube with corresponding dimensions, without any tapering or narrowing, for example, at the ejection end of the cannulas. In this way, a predefined annular gap is formed between the inner cannula and the surrounding outer cannula. The predefined annular gap has the specified dimensions and, in particular, a substantially constant distance between the inner and outer cannula. Its position and orientation are fixed and centered by the clamping inserts that firmly fix the cannulas in the nozzle body.

[0009] The nested inner and outer cannulas with their defined annular gap enable a self-centering effect through the compressed air or auxiliary gas flowing between them and back within the vessel. Due to the relatively thin cannulas and their correspondingly small wall thickness, the two cannulas are, in principle, adjustable and movable relative to each other. When the medium flows out through the inner cannula and compressed air is simultaneously supplied through the annular gap in the vessel, a kind of centering between the two cannulas is achieved, allowing for a defined and precisely metered spray pattern when the medium is ejected. Therefore, during use of the device, the inner and outer cannulas are always positioned at a fixed distance from each other and from the inner walls of the vessel, a distance determined by the vessel's diameter.Both cannulas are centered relative to the device's central axis X, yet their delicate design allows for relatively deep penetration of the device into the vessels and products being treated. The predefined annular gap, crucial for precise dosing, is therefore always maintained during operation, whether compressed air is being generated or another pressurized gas (e.g., inert gas) is being supplied, without the need for additional fixation or holding of the individual cannulas at intermediate positions or at the ejection end.

[0010] Preferably, the inner and outer cannulas are inserted into each other so that they are flush at the dispensing end. Alternatively, either the outer or the inner cannula can be positioned to protrude slightly from the other. This allows for further variations and modifications to the desired, clearly defined spray pattern or spray profile with the medium on the inner walls of the vessels being treated.

[0011] The device thus formed according to the invention, with a two-component nozzle consisting of two nested cannulas, also allows for the rapid exchange of elements, for example, for cleaning or to change the penetration depth (cannula length). For instance, cannulas of different lengths or thicknesses can be used in the same device simply by exchanging the respective clamping inserts with the hollow needles of the cannulas. The device also allows for improved spraying or application of medical products to their typically relatively confined internal areas. The inner surfaces of syringes, pipettes, glass tubes, or similar items can be easily and effectively sprayed with a medical product using the device, enabling very uniform distribution in both axial and radial directions.The amount of sprayed media or liquids can therefore be precisely adjusted. Furthermore, with the device according to the invention, it is also possible to define a specific area on the inner surfaces of such medical vessels or products onto which the product is to be sprayed.

[0012] By clamping the clamping inserts connected to the cannulas into the corresponding receptacles on the nozzle body, the invention also enables the secure fixation of even relatively thin-walled cannulas, which can be used for spraying such media. The cannulas of the inner and outer cannulas of the two-component nozzle are securely and centrally attached to the nozzle body by the clamping inserts at predefined positions. Furthermore, this makes it possible to easily connect additional ports for compressed air and for the supply of media, for example via a metering pump, to the nozzle body, even though the two-component nozzle with the cannulas has a relatively delicate design. With the device according to the invention, a wide variety of applications in the medical field for coating such internal surfaces of products can thus be easily implemented.Different shapes of inner and outer cannulas can be easily fixed to the same central nozzle body using the clamping inserts. This ensures quick and easy replacement, as well as quick assembly of the two-fluid nozzle. According to the invention, this design also allows for easier and faster cleaning of the components, for example, when switching to a different medium. The cannulas and the nozzle body can be completely disassembled.

[0013] According to the invention, the clamping inserts of the nozzle body have a conically tapered shape, and the nozzle body itself has correspondingly shaped conical receptacles. The nozzle body thus has conically formed receptacles for inserting the also conically tapered clamping inserts. The conically tapered shape of the receptacles and the clamping inserts has the advantage of ensuring automatic sealing and simultaneous centering with respect to a longitudinal axis (central axis X) of the two-fluid nozzle. Due to the form fit, the clamping inserts also create an annular gap between the cannulas and a reliable seal without the need for additional gaskets. The compressed air and the media are thus reliably sealed against leakage. The conicity of the receptacles and the clamping inserts for holding and securing the inner and outer cannulas creates a kind of force-fit connection between the cannulas in the clamping inserts.The nozzle body is generated. The cannulas are held securely in the desired position and location by the pressure and the conical shape of the receptacles and clamping inserts. Furthermore, the force-fit connection in the conical receptacles / clamping inserts ensures a reliable seal of the device's interior, as a relatively large-area force-fit connection is established across these conical shapes. The conically tapered shape can have a straight or curved taper. The respective receptacles have corresponding mating forms adapted to the clamping inserts. Advantageously, according to another aspect of the invention, the taper of the receptacles can also be slightly different from that of the clamping inserts, so that a linear seal is achieved by clamping or pressing the clamping inserts into the receptacles.

[0014] According to a further advantageous embodiment of the invention, the nested cannulas of the two-component nozzle are relatively thin-walled hollow needles with a wall thickness of 20 to 30% of the cannula's inner diameter. Advantageously, it has been shown according to the invention that such thin-walled hollow needles enable very precise spraying of media, even in narrow containers or medical products. For the purposes of this invention, hollow needles are also understood to include those that do not have a pointed tip at the front end, but are simply thin cylindrical tubes. The thin-walled hollow needles have the advantage that they allow the media to be sprayed over a relatively long area in the narrow interior of, for example, syringes or glass containers for medical products, while still allowing for relatively precise dosing of the amount of media sprayed.Due to the relatively thin shape of the hollow needles, a further advantage is that the escaping compressed air has sufficient space to flow out again, even in narrow containers, when spraying the media. This significantly reduces the flow velocity of the compressed air inside the containers compared to previously known devices of this type, preventing already applied droplets from detaching from the inner walls of the container. The thin-walled hollow needles have the advantage of creating a kind of self-centering effect in conjunction with the compressed air. Thus, despite the thin-walled cannulas, the two-fluid nozzle always remains in a central, focused position when applying and spraying the media inside such medical containers.The thin-walled hollow needles also have the advantage of allowing for relatively deep insertion and penetration into such hollow vessels of medical devices. This is not possible with conventional spray nozzles (two-fluid nozzles) with a relatively wide outer diameter.

[0015] According to a further advantageous embodiment of the invention, the annular gap for compressed air or inert gas between the inner and outer cannulas of the two-fluid nozzle has a dimension or gap width of less than 10%, preferably 6%, of the diameter of the inner cannula. A relatively narrow annular gap for the compressed air or pressurized inert gas has the advantage that sufficient atomization of the liquid medium from the inner cannula occurs and good distribution of the sprayed small droplets of the medium is enabled. Thus, very precise dosing of the amount of medium applied to the inner surfaces of the medical vessels is possible. Furthermore, the small annular gap for compressed air has the advantage that a specifically small droplet size for the medium can be set.The width of the annular gap defines the droplet size, while the amount of compressed air is variably adjustable via the atomization pressure to ensure a low flow velocity as the compressed air exits the interior of the vessels. According to the invention, the annular gap's dimensions, for example its width, can be easily adapted to specific conditions and requirements by using different cannula diameters. With a nozzle assembly thus formed, comprising an inner and outer cannula and annular gap, a uniform application of the media is achieved with sufficiently strong compressed air, without damaging the coating in the narrow interior areas of the vessels.

[0016] According to a further advantageous embodiment of the invention, the clamping inserts of the nozzle body, or at least one of the clamping inserts, are attached to the nozzle body by means of clamping caps, in particular by means of screw-on clamping caps. The clamping inserts with their clamping effect can thus be easily mounted and dismounted by screwing the clamping caps onto the nozzle bodies together with the cannulas provided therein, namely the inner cannula for the medium and the outer cannula for compressed air. This is also necessary, for example, to allow cleaning of the device when changing the medium to be applied. Furthermore, the secure sealing of the various areas by means of the clamping inserts can be easily achieved by simply screwing the clamping caps firmly onto the receptacles with the clamping caps.Alternative fastenings for the caps to fix the clamping inserts in the nozzle body, such as retaining springs, snap-on fasteners or bayonet fasteners, may be provided.

[0017] According to a further advantageous embodiment of the invention, the inner and outer cannulas of the two-fluid nozzle are arranged flush with each other at their respective front ejection points. The front end, namely the ejection point for compressed air, and the ejection point for media are thus realized in the same plane. This allows for thorough mixing between the liquid medium and the compressed air. Directly at the front ejection point of the two-fluid nozzle, the media are thoroughly mixed in conjunction with the interior and base of the vessel, thus enabling precise application and spraying of such medical media without the need for complex control of the metering pump and actuators.For very deep internal areas of vessels, actuators for the travel paths of the two-component nozzle can alternatively be used according to the invention, whereby a control system for actuating the actuators in conjunction with pump activation can then be provided. As an alternative to this embodiment of the invention, the inner cannula and the outer cannula can also be provided with a slight protrusion relative to each other. For example, the inner cannula can be provided with a slight protrusion of 0.2 mm relative to the outer cannula, so that further advantages and specific effects can be achieved in the dispensing and application of the media. Conversely, the inner cannula can also be slightly recessed relative to the outer cannula, which can have a protrusion of, for example, 0.2 mm to 0.5 mm.This makes it easy to achieve different nozzle effects at the exit point of the ejectors of the inner cannula and the outer cannula according to the invention, simply by changing the position of the nested cannulas relative to each other.

[0018] According to a further advantageous embodiment of the invention, the relative position of the front nozzles of the inner and outer cannulas is adjustable. With such an adjustable position, for example, the inner cannula can be positioned with a slight protrusion relative to the outer cannula, for example in the range of 0.1 mm to 0.3 mm, preferably 0.2 mm, by simply shifting them relative to the cannula. Conversely, with such an adjustable relative position of the two cannulas, the outer cannula can also be positioned with a slight protrusion relative to the inner cannula without requiring any complex modifications to the design. Different effects and spray profiles for various situations and different types of vessels or medical products can thus be effectively set and accommodated.

[0019] According to a further advantageous embodiment of the invention, the central nozzle body of the two-fluid nozzle of the device contains a cavity for supplying compressed air or inert gas to the two-fluid nozzle. The nozzle body is thus, according to the invention, an element provided internally with a cavity, which is supplied with compressed air or another auxiliary gas via a compressed air connection, the cavity being in flow communication with the annular gap between the inner and outer cannulas. This allows the compressed air to be reliably guided through the essentially very thin spaces between the inner and outer cannulas (gap between hollow needles) with a sufficient quantity and at a sufficiently high pressure. Precise and rapid ejection and atomization with the two-fluid nozzle is thus ensured at all times.After connecting both the compressed air to the compressed air port on the nozzle body and the media port (e.g., from a dosing pump), precise dosing and a accurately defined application of the required amount of active ingredients to the inner surfaces of medical products can be ensured. The nozzle body also provides a compact yet simple central element for holding the individual components: the inner cannula, the outer cannula, the clamping inserts, and the compressed air and media connections.

[0020] According to a further advantageous embodiment of the invention, the hollow needles of the inner and outer cannulas are thin-walled hollow needles with wall thicknesses ranging from 0.1 mm to 0.5 mm. The resulting air needle and metering needle, which consist of nested individual cannulas with relatively thin walls, are thus suitable for applying active ingredients or media even in deeper areas within medical vessels. The relatively thin two-component nozzles can be easily inserted into very narrow spaces and precisely adjusted there for spraying the media applied under compressed air. Surprisingly, with such relatively thin-walled cannulas, the invention has shown that a kind of self-centering occurs automatically inside the vessels.When applying media under compressed air, the front end, the ejecting end of the two-fluid nozzle, is essentially always held in a central position by the escaping compressed air alone, due to the thin-walled design of the two hollow needles – i.e., effectively centered. This makes the two-fluid nozzle particularly suitable for applying active ingredients within medical devices and products, such as syringes, pipettes, tubes, or similar items.

[0021] According to a further advantageous embodiment of the invention, a connection for compressed air or another pressurized auxiliary gas is provided on the nozzle body, arranged laterally, i.e., transversely to the medium line, relative to the longitudinal direction of the cannulas. The nozzle body and the two-fluid nozzle as a whole can thus be designed to be very compact according to the invention. The media connection, provided, for example, on a rear side, can be directly connected to the inner cannula at the clamping insert, while the compressed air connection can be provided laterally on the nozzle body without conflicting with the media connection. No additional channels or lines in the nozzle body are required. This makes the two-fluid nozzle suitable for quick switching between different media by simply changing the connection for the media between one line or another.The compressed air connection, which is located transversely on a side area of ​​the nozzle body, can remain unchanged, as the compressed air connection does not necessarily need to be changed even with different media.

[0022] According to a further advantageous embodiment of the invention, the clamping cap on the front side, on the side of the protruding cannulas, is formed with an externally tapered shape. At the ends facing the ejection point of the two-component nozzle, the clamping cap for the outer cannula and the clamping insert of the outer cannula is thus tapered towards the front. This facilitates deeper penetration into cavities of medical vessels or products. Furthermore, this prevents disruption of the compressed air flow exiting the vessel during application of the media. The compressed air and any remaining excess media can flow out of the interior of the vessel virtually without resistance, even in confined spaces. Finally, this shape has the advantage of further increasing the maximum penetration depth of the two-component nozzle.

[0023] According to a further advantageous embodiment of the invention, the clamping inserts of the two-component nozzle are adapted and designed to center the cannulas relative to a central axis X of the nozzle body or the device as a whole. The clamping inserts and the corresponding receptacles for the clamping inserts on the nozzle body are designed such that the cannulas attached therein, namely the air needle (outer cannula) and the metering needle (inner cannula) for media, are automatically and precisely centered relative to a central axis X of the nozzle body upon insertion. The clamping inserts thus have an advantageous centering function in addition to their holding and sealing functions. With this automatic centering, the hollow needles of the inner and outer cannulas are securely fixed in their relative position when inserted into one another, forming a predefined annular gap through which the compressed air can flow for spraying the media.This eliminates the need for complex machining of the two-fluid nozzle components to create nozzle channels or similar features in order to achieve a predefined shape for the nozzle body and cannulas. Simply inserting the clamping inserts into the concentrically designed receptacles or clamping inserts on the nozzle body automatically centers the cannulas.

[0024] According to a further advantageous embodiment of the invention, an adjustment unit for adjusting the relative position between the cannulas or the overall position of the cannulas is provided on at least one of the inner and outer cannulas. The adjustment unit can, for example, be implemented as a linear actuator or a servo motor that engages a holding element of the cannulas and thus allows them to change their relative position. With such an adjustment unit, variable spray patterns of the medium to be applied can be generated according to the invention. For example, depending on the position and relative orientation in the vessel to be treated, the relative position between the inner and outer cannula can be selectively changed to achieve a larger spray volume or a different spray radius of the sprayed medium. With such a measure, variable spray characteristics can be achieved when applying the medium.The adjustment of the relative position of the cannulas to each other via the adjustment mechanism can also be achieved, for example, in conjunction with the overall vertical stroke of the device when moving in and out of the interior of the medical vessels. For instance, a stronger spray pattern can be set in a first lower region than in an upper region by changing the position of the respective cannulas relative to each other during the vertical stroke, according to the invention. Such an adjustment unit can be implemented, for example, as a servo motor, screw mount, or linear actuator. Preferably, the adjustment unit is integrated into a part of the cannula retaining cap or into a retaining element for the cannula holder. The adjustment unit can also be built into and integrated within the nozzle body itself.

[0025] According to a further advantageous embodiment of the invention, at least one of the clamping inserts is attached to the nozzle body by means of a retaining cap with an adjusting element that is adjustable in the longitudinal direction of a central axis X of the device, such that the relative position between the cannulas can be changed. At least one of the caps for attaching the clamping inserts of the inner and outer cannulas is thus attached to the nozzle body via a special retaining cap. This retaining cap has an adjusting element with which the relative position of the respective cannula can be changed. For example, an inner cannula can be adjusted relative to the outer cannula by simply actuating the adjusting element on the retaining cap.This essentially provides a kind of holder for at least one of the clamping inserts for the cannulas, allowing for adjustment to adapt to different conditions and spray profiles or characteristics. This adjustability also offers advantages with regard to cleaning the device. For example, if deposits from the medium accumulate on the ejection end of the inner and outer cannulas, targeted cleaning can be achieved by removing the residue through relative adjustment between the inner and outer cannulas. In addition to this cleaning function, a dosing operation can also be implemented with the device according to the invention: By advancing, for example, the inner cannula relative to the outer cannula, targeted dosing of the medium alone can be achieved without spraying the medium, for example, by temporarily switching off the supply of compressed air (atomizing air).Instead of a simple dosing operation, this also allows for a special adjustment of the spray pattern so that a variable application of the medium to the inner walls of the vessels can be achieved in different areas.

[0026] According to a further advantageous embodiment of the invention, the clamping inserts are centered and sealed in the receptacles of the nozzle body by means of retaining caps, which are held to the nozzle body by an elastic spring, a bayonet fitting, or a snap-lock mechanism. The retaining caps are therefore not necessarily designed as screw-on clamping caps according to the invention. Instead of clamping caps, retaining caps can be provided that are held to the nozzle body by means of a spring element or another snap-lock element. A spring or spring element can provide a clamping effect instead of a screw-on clamping cap, generating a defined contact pressure for holding the cannulas to the nozzle body. Such a spring can, for example, be inserted between the nozzle body and a receiving area of ​​the retaining caps.Various types of springs are known to experts in the field to be suitable for this purpose. Alternatively, a bayonet fitting or a snap-lock fastener can be used to secure the retaining caps to the nozzle body. Compared to screwing the retaining caps to the nozzle body, these designs offer the advantage of allowing quick assembly and disassembly of the individual parts, especially the cannulas, from the nozzle body. This is advantageous when converting from one type of cannula to another with a different length or diameter, or for cleaning purposes, for example. The individual components, and especially the cannulas, can be removed and reattached to the nozzle body very quickly, even without tools.According to the invention, such retaining caps with a clamping function via springs or by means of a bayonet fitting or snap closure can also be easily manufactured, for example as injection-molded parts, which can be readily produced with the appropriate material properties for the required spring action of fixation to the nozzle body. This results in a cost-effective and user-friendly design of the devices.

[0027] According to a further advantageous embodiment of the invention, at least one of the cannulas is securely fixed to the clamping inserts by means of an end-side retaining element, in particular by a crimp, a crimp, or an adhesive bond. This ensures a secure hold of the inner or outer cannula in the respective clamping inserts within the nozzle body. Slippage or displacement of the individual cannulas is thus effectively prevented. The fixing or retaining element in the form of a crimp can, for example, be implemented as a bend at the inner (rear) end of the cannulas within the nozzle body. Alternatively, another method of securely fixing the cannula in the clamping insert can be provided, for example, by crimping or by bonding to the clamping inserts, so that the relative position of at least one of the cannulas is firmly fixed.Nevertheless, both the outer and inner cannulas have a substantially constant cross-section and diameter along their longitudinal extent, as already explained above with respect to claim 1. Other alternative methods of fixing the cannulas in the clamping inserts can also be used. For example, a press fit of the cannulas in the material of the clamping inserts can be provided. Detachable methods of fixing, for example via threads or screw elements, are also conceivable within the scope of the present invention.

[0028] According to a further advantageous embodiment of the invention, an air guide or flow direction element for the compressed air or pressurized inert gas is provided inside the nozzle body, for example, in the cavity within the nozzle body. A flow direction element, which is provided, for example, between the inlet on the nozzle body and the inner (rear) end of the outer cannula, has the advantage that the flow of compressed air is applied very uniformly around the annular gap between the outer and inner cannulas with a consistent pressure distribution. This improves the supply and ensures a uniform generation of compressed air inside the annular gap. This further enhances the self-centering effect of the two nested cannulas resulting from their function and design.The uniformly introduced airflow, with a consistent flow velocity within the nozzle body, reliably centers the position of the inner and outer cannulas, even at their free ends, to maintain the shape of the predefined annular gap for the most precise metered application of the medium. Other flow elements can also be provided within the nozzle body in the area of ​​the compressed air or gas supply: for example, air guide elements or channels. A flow guide element according to the invention preferably has a tubular, constant cross-section, resembling a sleeve element. Other flow guide elements can also be used.Such measures allow for the targeted and easy adjustment of the shape and distribution of the compressed air for the precisely defined generation of the atomized liquid, according to the respective specifications and requirements. A kind of nozzle effect can thus be created within the nozzle body itself using simple means, or varied as needed.

[0029] Furthermore, a device for spraying or applying liquid media under compressed air or by means of a pressurized gas, such as inert gas, is disclosed, which is particularly designed and adapted for spraying or applying the media to the inner surfaces of medical products or narrow vessels and which has a two-component nozzle made of at least two nested cannulas with a substantially constant diameter over their longitudinal extent, with a nozzle body designed as a holder for the two-component nozzle, which has at least one inlet each for a medium and for compressed air or inert gas under pressure, wherein the device is characterized by a nozzle body which has clamping inserts adapted to receptacles for a sealed holder and fixation of an inner cannula for media and an outer cannula for compressed air or inert gas in the form of hollow needles,The clamping inserts on the nozzle body are provided for securing the nested cannulas, forming a predefined gap between the inner and outer cannulas in corresponding receptacles of the nozzle body. According to the invention, a device is thus provided which essentially consists of two hollow needles in the form of an inner cannula and an outer cannula, which are held and fixed in a nozzle body, namely a central holding element. The two nested cannulas are each held and fixed in the nozzle body by means of clamping inserts. The inner and outer cannulas are nested together in such a way that an annular gap with predefined dimensions is formed between them.This nozzle allows compressed air or another pressurized gas to flow outwards while simultaneously allowing a medium to flow out through the inner cannula. This type of two-fluid nozzle with two nested cannulas minimizes the impact of the reduced velocity of the outgoing compressed air. The reduced airflow velocity prevents droplets already applied to the inner walls of the containers from being carried away and removed. The corresponding recesses in the nozzle body are designed so that the nested cannulas can be inserted and securely sealed using the clamping inserts. These clamping inserts offer the advantage of automatically centering and sealing the respective compressed air and medium supply areas.

[0030] Further features, aspects, and advantageous embodiments of the invention will be described in more detail below with reference to exemplary embodiments, which are explained in conjunction with the accompanying drawings. The drawings show: Fig. 1 shows a cross-sectional view of a first embodiment of a device according to the invention with a detailed front view. Fig. 1a Fig. 2 a sectional view of an embodiment of a device according to the invention for spraying media in an application on a medical vessel to illustrate the function of the two-component nozzle with nested hollow needles; Fig. 3 an enlarged cross-sectional view of the first embodiment of the device according to the invention in the area of ​​the nozzle body with clamping inserts for the inner and outer cannulas and connections for compressed air and media supply; Fig. 4 several views of the sequence of the method for applying media with the embodiment of a device with a two-component nozzle according to the invention. Fig. 1 bis 3 on an example of a medical vessel with steps A) to E); Fig. 5 a cross-sectional view of a second embodiment of a device according to the invention with an adjusting unit for adjusting the relative position between the inner cannula and the outer cannula; Fig. 6 a partial cross-sectional view of a third embodiment of a device according to the invention with a snap-lock fastener for fixing the retaining caps for the clamping inserts of the cannula; Fig. 7 a partial cross-sectional view of a fourth embodiment of a device according to the invention with a flow-directing element for compressed air or compressed gas; and Fig. 8 a partial cross-sectional view of a fifth embodiment of a device according to the invention with a retaining element provided as a crimp on the outer cannula.

[0031] In the Fig. 1 and the resulting enlarged detail view of Fig. 1a Figure 1 shows a first embodiment of a device 10 according to the invention for spraying or applying liquid media to surfaces under compressed air with a two-component nozzle 1 in a cross-sectional view, wherein in Fig. 1a The front ejector is shown enlarged in a top view to illustrate the two-fluid nozzle 1 formed from nested cannulas 2, 3 with an annular gap 14. In this embodiment, the device 10 comprises a central nozzle body 4, which, together with the cannulas 2, 3, essentially forms the two-fluid nozzle 1. The cannulas 2, 3, which are formed as thin-walled hollow needles, namely the inner cannula 2 and the outer cannula 3, are attached to the nozzle body 4 in clamping inserts 5 provided for this purpose. The outer cannula 3 is located at its left end in the Fig. 1 The clamping insert 5 is inserted into a correspondingly formed receptacle 7 of the nozzle body 4 and secured there in a sealing and centered manner. For this purpose, clamping caps 13 are provided on each of the clamping inserts 5, 6 for the two hollow needles 2, 3, which are firmly fixed to the nozzle body by screwing them on, thereby securing the clamping inserts 5, 6 firmly and securely in the respective receptacles 7, 8.

[0032] The internal structure of the two-fluid nozzle 1 of the device 10 is also shown again in an enlarged view of this embodiment in the Fig. 3 As shown. A connection 12 for compressed air is provided laterally on the nozzle body 4, i.e., transversely to the longitudinal direction of the two-fluid nozzle 1. In this embodiment, a compressed air fitting is screwed into the nozzle body 4 at the compressed air inlet 12, which is periodically supplied with compressed air by a compressed air supply (not shown in detail). The front end of the compressed air inlet 12 points into an inner cavity 15 in the nozzle body 4, from which the compressed air flows into the annular gap 14 between the inner cannula 2 and the outer cannula 3. At the rear end of the two-fluid nozzle 1 (right in Fig. 1 A screw-in connection on an inlet 11 for media is shown. A liquid medium, for example a medical device such as heparin or similar, is introduced into the two-component nozzle via this media connection 11. Supplyed by a metering pump (not shown), the media is thus fed to the two-component nozzle 1 of the device 10 and, together with the compressed air from the cavity 15 in the inner region of the nozzle body 4, is directed into the hollow needles 2, 3. The compressed air expelled at the front nozzle then mixes with the liquid media from the inner cannula 2, so that precise and well-metered application of the media to surfaces in, for example, a medical container 20 is achieved.

[0033] This process is repeated in the Fig. 2 The invention is illustrated in conjunction with the application of media in a medical vessel 20. The air and media exiting at the front nozzle of the inner cannula 2 and outer cannula 3 are redirected by 180° at the bottom of the vessel 20, and the finely atomized droplets are evenly applied to the inside of the vessel. The dispensed quantity, which can be adjusted accordingly by a metering pump and control system, is thus distributed on the inner surfaces of the vessel 20, and the compressed air flows upwards out of the upper opening of the vessel 20. With a simultaneous process of the device 10 with the two-component nozzle 1 from the interior of the vessel 20 (see figure 1), the air is expelled from the inner region of the vessel 20. Fig. 4 This ensures the precise application of a predefined spray quantity of media to specific areas of the inner surfaces of medical products.

[0034] The Fig. 2 Figure 1 shows a cross-sectional view of an embodiment of the device 10 according to the invention with a two-component nozzle 1 in an application for applying a liquid medical product to the inner surface of the vessel 20, in an application to illustrate the function and advantages of the invention. As can be seen from the Fig. 2 As can be clearly seen, the two-fluid nozzle, which extends deep into the interior of the narrow vessel 20, with its narrow inner cannula 2 and narrow outer cannula 3, is suitable for applying and spraying liquid media onto the inner surfaces of the vessel 20, even in interior areas with a small inner diameter. Due to the annular gap 14 (see figure 3), the nozzle is designed to allow for the application and spraying of liquid media onto the inner surfaces of the vessel 20, even in interior areas with a small inner diameter. Fig. 1a The compressed air exiting the inner cannula 2, along with the discharged media, is forced by a metering pump from the flow channel of the inner cannula 2, creating a downward and laterally upward flow along the inner walls of the vessel 20. This results in an advantageous effect according to the invention: The relatively thin-walled inner cannula 2 and the relatively thin-walled outer cannula 3, which, for example, have wall thicknesses in the range of 0.1 mm to 0.5 mm, are automatically centered relative to each other by the air and media flows. This enables the precise application and spraying of well-metered quantities of an active ingredient or medium, such as a medical product like heparin or BCA. (Blood Clotting Accelerant) or EDTA (Ethylendiamintetraacetat) may be.

[0035] The device 10 according to this embodiment in the Fig. 2 The nozzle body 4 has a central cavity 15 for the compressed air, which flows out into the annular gap 14 between the inner cannula 2 and the outer cannula 3. The size of the annular gap 14 can be easily varied by simply exchanging the cannulas 2 and 3 for different diameters. The outer cannula 3 is held in a clamping insert 5 in the nozzle body 4 by means of a clamping cap 13, thereby automatically achieving a secure seal, centering, and fixation of the position of the inner cannula 2 relative to the outer cannula 3. This positive-locking and force-locking connection of the conical shape between the receptacle 7 on the nozzle body 4 and the clamping insert 5 ensures both a sufficient seal and a secure hold of the cannulas 2 and 3 with a predefined annular gap 14. This reliably prevents the escape of compressed air or liquid media.

[0036] The Fig. 3 Figure 1 shows an enlarged cross-sectional view of the first embodiment of the device 10 according to the invention with a two-fluid nozzle 1 in the area of ​​the nozzle body 4. The internal structure with two nested cannulae 2, 3 of the two-fluid nozzle 1, which are fixed and held on the nozzle body 4 by respective clamping inserts 5, 6, can be seen in more detail. The clamping inserts 5, 6 are preferably made of a plastic material, so that they allow for a force-fit retention of the cannulae 2, 3 (hollow needles) and a secure seal on the, for example, metallic nozzle body 4. The annular gap 14 is thus automatically formed between the compressed air-supplied cavity 15 and the front ejection end of the two-fluid nozzle 1. The compressed air inlet 12 is provided with a screw-in connection fitting to which a compressed air-supplied compressed air hose (not shown) is connected. At the rear end of the two-fluid nozzle 1 (right in Figure 1) Fig. 3 A screw fitting for connecting a media supply in the form of a hose or similar is provided at the inlet 11 for media, which is equipped with a controllable dosing pump and controller (not shown in the diagram). Fig. 3 The clamping insert 5 in the first receptacle 7 has a bore or opening x1 with a first diameter d1, which corresponds at least partially to the outer diameter of the outer cannula 3. The other clamping insert 6 in the second receptacle 8 has an opening or bore x2 with a different diameter, the diameter d2 of which corresponds at least partially to the outer diameter of the inner cannula 2. Both bores x1, x2 are concentric with a common central axis X.

[0037] By moving the two-fluid nozzle 1 out of the interior of the vessel 20, the supply of the media together with the supply of compressed air is controlled so that the flows correspond to the flow arrows of the Fig. 2 Due to the narrow design of the cannulas 2 and 3, there is sufficient space for the escaping compressed air, preventing the generation of harmful high flow velocities. The ejected media are thus mixed with the compressed air at the nozzle tip and atomized and applied as defined, small droplets on the order of < 0.5 mm. This allows for very precise dosing of the ejected media to be applied to the vessel 20. The precisely adjustable spray pattern is thus achieved in both axial and radial directions with a very uniform distribution. The quantities of media ejected are, for example, in a variable range of 5 to 60 µl. Both the clamping insert 5 for the outer cannula 3, in the form of a thin-walled hollow needle, and the clamping insert 6 for the inner cannula 2 for the media are firmly fixed in the receptacles 7 and 8, and are thus precisely centered and positioned, sealing within the nozzle body 4.The clamping inserts 5, 6 are screwed firmly onto the nozzle body using the preferably screw-on clamping caps 13, thereby achieving an effective seal. Nevertheless, the components can be quickly disassembled, e.g., for cleaning purposes or for replacement with cannulas 2, 3 of a different diameter or length.

[0038] In the Fig. 4 Various process steps A, B, C, D, and E of an application example of an embodiment of the device 10 according to the invention, with a two-fluid nozzle 1 for spraying media onto an inner surface area of ​​medical vessels 20 in the form of bottomed tubes, are shown. The device 10 is moved into the interior of the vessel 20 with the ejecting end of the two-fluid nozzle 1 (step A). ​​After insertion and setting the starting point for spraying the media inside the vessel 20 (step B), the two-fluid nozzle 1 of the device 10 is simultaneously activated, along with the activation of the metering pump for the media and the compressed air supply to the compressed air connection 11, and is then gradually moved out of the interior of the vessel 20 (see step C).

[0039] Compressed air is sprayed through the relatively narrow annular gap 14 of the two cannulas 2, 3 and distributed with the media from the inner cannula 2. The media is then precisely metered and applied to the inner surface of the vessel 20 and sprayed in precisely predefined quantities as required, according to the adjustment movement of the device 10 (see steps C and D). The spray volume and the size of the atomized droplets are very precisely adjustable, allowing for optimized application of active ingredients in medical products 20 compared to the prior art. Shortly before or after the device 10 extends from the inner surface of the vessel 20 (step E), the metering pump for the media is switched off and the compressed air supply is terminated.

[0040] In the Fig. 5 The second embodiment of the device 10 according to the invention, shown in a cross-sectional view, has a fundamentally similar structure to the first embodiment described above. In addition, an adjustment unit 16 is located at the right end in the Fig. 5 for adjusting the inner cannula 2 relative to the outer cannula 3. For this purpose, the clamping insert 6 of the inner cannula 2, which is inserted into the conically enlarged receptacle 8 on the nozzle body 4 in a corresponding shape, is not clamped by a clamping cap 13, but by means of a type of retaining cap 17, which allows a relative displacement of the inserted adjusting element 9 of the adjusting unit 16, as indicated by the arrow R in the Fig. 5 This is illustrated. The inlet 11 for the medium is located inside the adjusting element 9 of the adjusting unit 16. The inner cannula 2 is fixed to a U-shaped insert screwed into the retaining cap 17 and, together with the latter, can be adjusted as needed along the longitudinal axis X of the device 10 by a servo motor, a linear actuator, or the like. Thus, the relative position between the inner cannula 2 and the outer cannula 3 can be changed as required and for various purposes, for example, to adjust the spray cone. For instance, different spray profiles can be achieved at the ejector (left side in the illustration). Fig. 5 The adjustment of the cannulae 2, 3 is achieved by adjusting the annular gap 14 not by flush-fitting cannulae 2, 3, but by slightly offsetting them relative to each other. This also allows, for example, cleaning functions of the device 10 to be implemented: If the front nozzle becomes encrusted at the annular gap 14, the cannulae 2, 3 can be adjusted relative to each other using the adjustment unit 16, causing the encrusted elements to break off or detach. Other functions, such as targeted metering of medium without a supply of compressed air, can also be achieved by advancing the inner cannula 2 relative to the outer cannula 3 and at least briefly stopping the supply of compressed air via the inlet 12. With this design, not only can different spray profiles and other functions be implemented with the device 10 without the complex additional constructions described above.This also allows for better adaptation to the respective dimensions, shapes and conditions of the medical vessels to be treated.

[0041] The Fig. 6 Figure 1 shows a third embodiment of a device 10 according to the invention, again in a partial cross-sectional view, with an alternative form of attachment of the retaining caps 18 to the nozzle body 4. In this embodiment, instead of a screw connection for fixing the clamping caps 13, which is partially shown in the previous embodiments, the retaining cap 18 is implemented with a snap-lock mechanism 19, which is achieved by means of appropriately shaped recesses and projections and a certain degree of elasticity in the material of the retaining cap 18. By simply attaching and clipping the retaining cap 18, the clamping insert 5 for the outer cannula 3 is securely fixed in the corresponding conical receptacle 7. The snap-lock mechanism 19 generates a kind of preload and clamping force that ensures a secure seal and fixation of the outer cannula 3 to the nozzle body 4.An analogous, corresponding method of securing the inner cannula can be used on the opposite side, not in the . Fig. 6 The other end of the nozzle body 4 shown can also be provided. Instead of the snap-lock fasteners 19 shown here, other forms of holders or retaining devices can also be provided for attaching the retaining caps 17, 18 or clamping caps 13. For example, instead of the screw connections as in the first embodiment, bayonet fittings or spring elements can also be used to ensure the necessary clamping force and holding effect of the caps 13, 17, 18 on the nozzle body for fixing and holding the clamping inserts 5, 6. In the embodiment of the Fig. 6 Furthermore, as described below, a flare 3.1 is provided at the rear (inner) end of the outer cannula 3, which ensures secure retention and prevents the outer cannula 3 from slipping out of the clamping insert 5. In this example, a flow guide 21 is also included. Fig. 6 shown, which is mounted for aligning and equalizing the flow velocity of the compressed air for introduction into the annular gap 14 in the cavity 15, as will be explained further below.

[0042] A fourth embodiment of a device 10 according to the invention for spraying liquid media is described in the Fig. 7 This is shown in a partial cross-sectional view. In this fourth embodiment, a flow guide 21 is inserted inside the cavity 15 of the nozzle body 4 between the inlet 12 for compressed air or compressed gas and the inlet to the annular gap 14 at the rear end of the outer cannula 3. In this example, the flow guide 21 has a double-sleeve shape with a constant cross-section. The incoming compressed air from the inlet 12 is thus distributed evenly and directed towards the annular gap, ensuring the most uniform possible generation of compressed air at the inlet of the annular gap 14 and thus up to the front ejection end of the cannulas 2, 3. The compressed air flows through the flow guide 21, which has a narrower cross-section compared to the cavity 15, and is thereby distributed evenly and directed precisely around the annular gap 14 to the inlet between the inner cannula 2 and the outer cannula 3.This further improves the flow characteristics and the compressed air effect in the device 10 according to the invention. The self-centering effect is also further enhanced by the narrow shape of the annular gap 14 and the relatively thin-walled inner cannulas 2 and outer cannulas 3. During use, the cannulas 2 and 3 self-center relative to each other and to the interior of a medical vessel 20 being treated due to the introduced compressed air (see figure). Fig. 2 and Fig. 4 ). In this example of the Fig. 7 Here too, the outer cannula 3 is securely fixed at its rear end behind the clamping insert 5 inside the nozzle body 4 by means of a crimp 3.1. The fixing of the outer cannula 3 can also have a different form, for example, a clamping fit or an adhesive bond in the bore of the clamping insert 5. As illustrated, the various aspects of the illustrated embodiments of the invention can also be combined with one another in order to adapt the device 10 variably according to the requirements and the specific functionalities desired.

[0043] In the Fig. 8A fifth embodiment of a device 10 according to the invention for spraying or applying liquid media is shown. In this embodiment, the outer cannula 3 is firmly fixed inside the nozzle body, namely at the rear end of the clamping insert 5, by means of a crimp 3.1 as a retaining element. Displacement of the outer cannula 3 is reliably prevented even at high pressures from the compressed air coming from the inlet 12. The firm fixing of the outer cannula 3 or, alternatively, the inner cannula 2 can also be achieved by means other than crimping: crimping or bonding within the respective clamping inserts 5, 6 is also conceivable.In the design of the device 10, which provides adjustability for at least one of the cannulae 2, 3, the fixation of the cannulae 2, 3 is selected such that a relative displacement of their position is enabled by a screw or sliding mechanism via a servomotor or similar device. The sealing can be achieved in a separate element from the clamping inserts 5, 6, in which the fixed fixation for the adjustability is then carried out.

[0044] The various aspects of the invention presented can also be combined with one another, as is already partially shown with the variants of the illustrated embodiments in conjunction with the drawings. In particular, the type and form of fastening the inner cannula 2 and the outer cannula 3 can vary. Retaining caps 17, 18 as well as clamping caps 13 can be used for this purpose. The basic structure of the nozzle body 4 can also be designed symmetrically, as partially shown in the figures of the embodiments. An asymmetrical shape of the nozzle body 4 and the device 10 as a whole is also conceivable, for example, if a projecting mounting flange is required on one side for mounting to adjacent components.In alternative embodiments of the invention, the shape of the clamping inserts 5, 6 can also be provided differently than with the straight conical shape in the manner of a truncated cone, as long as the outer cannula 3 and the inner cannula 2 are securely held and mounted inside the nozzle body 4 to produce a defined and firmly fixed annular gap 14.

[0045] Compressed air has been described as a pressure medium for producing the atomization. Other types of pressurized or auxiliary gases can also be used within the scope of the invention. For example, in certain applications, an inert gas can be used to minimize the reaction of the pressurized gas with the environment. For instance, CO₂ can be used to maintain a low-reactivity O₂ environment in the spraying area of ​​the device 10, which is important in certain medical applications.

Claims

1. Device (10) for spraying or applying a medium using an auxiliary gas in the form of compressed air or inert gas under pressure, in particular on the inner sides of medical products or vessels, with a two-substance nozzle (1) consisting of at least two cannulas (2, 3) inserted into one another and having a substantially constant diameter over their longitudinal extent, with a nozzle body (4) designed as a holding for the two-substance nozzle (1), which has at least one inlet (11, 12) for the medium and for the auxiliary gas in each case, characterised in that clamping inserts (5, 6) adapted to receptacles (7, 8) for a sealed holding and fixing of an inner cannula (2) and an outer cannula (3) are arranged on the nozzle body (4), the clamping inserts (5, 6) for fastening the cannulas (2, 3) inserted into one another with the formation of a predefined gap (14) between inner cannula (2) and outer cannula (3), characterised in that the clamping inserts (5, 6) have a conically tapered shape and the nozzle body (4) has correspondingly conically shaped receptacles (7, 8).

2. Device (10) according to claim 1, characterised in that the cannulas (2, 3) inserted into one another are relatively thin-walled hollow needles with a wall thickness of 20% to 30% of the inner diameter of the cannulas (2, 3).

3. Device (10) according to any of the preceding claims, characterised in that the gap or annular gap (14) for compressed air or inert gas between the inner cannula (2) and the outer cannula (3) has a dimension of less than 10%, preferably 6%, of the diameter of the inner cannula (2).

4. Device (10) according to any of the preceding claims, characterised in that at least one of the clamping inserts (5, 6) is fastened to the nozzle body (1) by means of a clamping cap (13), in particular a screwable clamping cap (13).

5. Device (10) according to any of the preceding claims, characterised in that the inner cannula (2) and the outer cannula (3) are arranged flush with one another at the front discharge end.

6. Device (10) according to any of the preceding claims, characterised in that the relative position of front discharge ends of the inner cannula (2) and the outer cannula (3) is adjustable.

7. Device (10) according to any of the preceding claims, characterised in that a cavity (15) is provided in the nozzle body (4) for feeding compressed air or inert gas into the two-substance nozzle (1).

8. Device (10) according to any of the preceding claims, characterised in that the cannulas (2, 3) are provided as hollow needles, the hollow needles of the cannulas (2, 3) being thin-walled in the range of wall thicknesses between 0.1 mm and 0.5 mm.

9. Device (10) according to any of the preceding claims, characterised in that a laterally arranged connection (12) for compressed air is provided on the nozzle body (4) in relation to the longitudinal direction of the cannulas (2, 3).

10. Device (10) according to any of the preceding claims, characterised in that the clamping cap (13) is conically tapered on the outside on the side of the cannulas (2, 3).

11. Device (10) according to any of the preceding claims, characterised in that the clamping inserts (5, 6) are adapted to centre the cannulas (2, 3) of the two-substance nozzle (1) in relation to a central axis (X) of the nozzle body (4).

12. Device (10) according to any of the preceding claims, characterised in that an adjusting unit (16) for adjusting the relative position between the cannulas (2, 3) is provided on at least one of the inner cannula (2) and the outer cannula (3).

13. Device (10) according to any of the preceding claims, characterised in that at least one of the clamping inserts (5, 6) is fastened to the nozzle body (4) by means of a holding cap (17) with an adjusting element (9), which is adjustable in the longitudinal direction of a central axis (X), in such a way that the relative position between the cannulas (2, 3) can be changed.

14. Device (10) according to any of the preceding claims, characterised in that the clamping inserts (5, 6) are centred and fixed in a sealing manner in the receptacles (7, 8) via holding caps (18), which are held on the nozzle body (4) by means of an elastic spring, a bayonet lock or a snap-in lock (19).

15. Device (10) according to any of the preceding claims, characterised in that at least one of the cannulas (2, 3) is fixed to the clamping inserts (5, 6) in a fixed manner by means of a holding means at the end, in particular by flanging (3.1), crimping or gluing.

16. Device (10) according to any of the preceding claims, characterised in that an air guiding or flow directing element (21) for the compressed air or an inert gas under pressure is provided in the nozzle body (4).

17. Device according to any of the preceding claims, wherein a first receptacle (7) or clamping insert (5) has an opening or bore (x1), the diameter (d1) of which corresponds at least in sections to an outer diameter of the outer cannula (3), wherein a second receptacle (8) or clamping insert (6) has an opening or bore (x2), the diameter (d2) of which differs from the diameter (d1) of the first receptacle (7) and corresponds at least in sections to an outer diameter of the inner cannula (2), and wherein the bores (x1, x2) are arranged in particular concentrically with respect to a common central axis (X).

18. Device (10) for spraying or applying liquid media under compressed air supply or by means of compressed gas, in particular on the inner sides of medical products or vessels, according to any of claims 1 to 18, with a two-substance nozzle (1) consisting of at least two cannulas (2, 3) inserted into one another with a substantially constant diameter over their longitudinal extent, with a nozzle body (4) designed as a holding for the two-substance nozzle (1), which has at least one inlet (11, 12) for the medium and for compressed air or an inert gas, characterised in that clamping inserts (5, 6) adapted in each case to the shape of receptacles (7, 8) are provided on the nozzle body (4) for a sealed holding and fixing of an inner cannula (2) for media and an outer cannula (3) for compressed air in the form of hollow needles, which are provided for fastening the cannulas (2, 3) inserted into one another with the formation of a predefined gap (14) between inner cannula (2) and outer cannula (3) in the corresponding receptacles (7, 8).

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