EP0657222A1 - Injector nozzle - Google Patents

Abstract

The invention relates to an injector nozzle for generating air-filled liquid drops, with a metering-nozzle element (2), with a mixing chamber (5), following the latter and provided with an air-suction orifice, for generating a liquid/air mixture, and with an outlet element (7). A particularly high uniformity and largely fluctuation-free distribution characteristic of the liquid drops is achieved in that there is provided between the mixing chamber (5) and the outlet element (7) a homogenising and calming space (13), the inlet cross-section of which is enlarged abruptly relative to the outlet cross-section of the mixing chamber (5). <IMAGE>

Description

The invention relates to an injector nozzle for generating air-filled liquid drops, according to the preamble of claim 1.

So-called two-component nozzles in various embodiments are already known. For example, a liquid and a gaseous medium are fed to these nozzles under pressure, these media being mixed with one another within a mixing chamber. When using such nozzles for the application of crop protection agents, additional air is usually only used to increase the speed of the particles or droplets or to refine the drop spectrum, i.e. used to reduce the mean drop diameter. Due to a relatively high consumption of additional air and the need for a pressure generator, such nozzle systems are technically relatively complex and not very practical. In addition, the air pressure influences the amount of liquid sprayed out, which means that the technical effort is increased by devices for regulating or maintaining the quantity.

For the application of crop protection agents, injector nozzles with automatic air intake are also known, particularly in the case of hand-operated small devices. The advantage of such injector nozzles lies in the unproblematic flow control via the liquid pressure, in a reduced susceptibility to wind due to the discharge of crop protection agents due to greatly enlarged droplet diameters, and in an improvement in the coating structure on the target surface, since the air-filled drops on impact, for example, on plant surfaces burst, whereby larger wetting surfaces are achieved with the same volume of liquid. Due to the expansion of the compressed air or gas particles as they leave the nozzle, the drops experience an additional acceleration, which enables better penetration of the target stocks. However, an inhomogeneity of the liquid-air mixture generated in front of the nozzle outlet opening has proven to be disadvantageous in these known injector nozzles. This creates strong pulsations in the liquid supply, with the result that extremely different droplet sizes and large fluctuations in the distribution characteristics and in the discharge of the liquid-air mixture occur in the micro range at the nozzle outlet opening.

The invention is therefore based on the object to provide an injector nozzle of the type required in the preamble of claim 1, which while maintaining the above-described advantages of the known designs and with a relatively simple construction by a particularly high uniformity of the drop sizes and a largely fluctuation-free distribution characteristic of these Excellent drop of liquid.

This object is achieved by the characterizing part of claim 1.

Advantageous refinements and developments of the invention are the subject of the dependent claims.

In the injector nozzle according to the invention there is a homogenizing and mixing element between the mixing chamber and the outlet element Calming space is provided, the inlet cross section of which is abruptly enlarged compared to the outlet cross section of the mixing chamber. As a result of this measure, the liquid-air mixture formed in the mixing chamber and emerging therefrom is calmed in a space immediately adjacent in the direction of flow and is homogenized particularly favorably in the process. This homogenizing and calming space can be designed, for example, as an air chamber-like cavity and acts to a certain extent as a pulsation damper or pressure accumulator, as a result of which the undesirable fluctuations, such as occur in the known designs explained, can largely and generally even be completely avoided, and this also for so-called micropulsations applies. Through a sensible design of this homogenizing and calming space, a particularly high uniformity in the size of the liquid drops is achieved with an essentially fluctuation-free distribution characteristic. The air-filled liquid droplets emerging from the outlet opening of the outlet element of this injector nozzle are extremely unaffected by the wind and thus ensure an optimal coating structure of the ejected liquid on a target surface, for example on plant surfaces, when it comes to the application and distribution of crop protection agents.

It is particularly expedient if, in the injector nozzle according to the invention, the inlet cross-section of the homogenizing and calming space is approximately 1.5 to 9 times the value, preferably 3 to 5 times the value of the outlet cross-section of the mixing chamber.

In this embodiment according to the invention, the cavity forming the homogenizing and calming space can have at least about twice the volume as the mixing chamber, the shapes and configurations of this space being able to be adapted to various purposes in an extremely favorable manner. Accordingly, the homogenization and calming space can have an overall length that is greater than the length of the mixing chamber.

Furthermore, it can be particularly advantageous if the homogenizing and calming space has a rear area that surrounds the component forming the mixing chamber in a ring. In this embodiment of the space mentioned, the liquid-air mixture flowing in from the mixing chamber partially expands. against the general flow direction backwards - which has a particularly favorable effect on avoiding micropulsations.

If necessary, the uniformity of the size of the liquid drops can also be improved in an advantageous manner by providing a perforated element, preferably formed by a wire mesh or a perforated plate, between the mixing chamber and the outlet element.

It can also be advantageous if the air intake opening of the mixing chamber can be connected to a device, preferably a throttle device, for changing the amount of air sucked in. In this way, the drop exit speed and drop size can be influenced if necessary.

The air intake opening of the mixing chamber can also be connectable to an air system under excess pressure, preferably to the exhaust system of a carrier vehicle. This can be the case, for example, if the injector nozzle belongs to an injection unit with which crop protection agents are to be applied and which is carried by a motor vehicle with an internal combustion engine.

In some applications, it may also be expedient to provide at least one additional suction opening for feeding further liquids and / or gases into the mixing chamber, which, for example, could be designed and attached similarly to the air suction opening of the mixing chamber.

Fig.1

einen Axial-Längsschnitt durch eine erste Ausführungsform der erfindungsgemäßen Injektordüse;

Fig.2

eine auseinandergezogene Perspektivansicht dieser erfindungsgemäßen Injektordüse;

Fig.3 bis 7

ähnliche Axial-Längsschnitte wie Fig.1, jedoch zur Erläuterung einiger weiterer Ausführungsformen, insbesondere im Bereich des Homogenisier- und Beruhigungsraumes;

Fig.8 und 9

ähnliche Axial-Längsschnitte wie Fig.1, jedoch zur Erläuterung einiger Ausführungsvarianten für das Austrittselement.

The invention is described in more detail below with the aid of a few exemplary embodiments illustrated in the drawing. Show in this drawing

Fig. 1

an axial longitudinal section through a first embodiment of the injector nozzle according to the invention;

Fig. 2

an exploded perspective view of this injector nozzle according to the invention;

Fig. 3 to 7

Axial longitudinal sections similar to FIG. 1, but to explain some further embodiments, in particular in the area of the homogenizing and calming space;

Fig. 8 and 9

Similar axial longitudinal sections as Figure 1, but to explain some variants of the outlet element.

The overall construction of the injector nozzle according to the invention will first be explained with reference to the first exemplary embodiment illustrated in FIGS. 1 and 2. This injector nozzle 1 is designed to generate air-filled liquid drops and contains as main components a metering nozzle element 2 for generating a liquid jet, a central nozzle body 3 with a mixing chamber 5, which is formed centrally therein and follows the metering nozzle element 2 in the direction of flow (arrow 4) of the liquid jet, which has a Air intake opening 6 is provided and serves to produce a liquid-air mixture, and an outlet element in the form of a distributor mouthpiece 7, which is provided with at least one outlet opening 8 for the liquid-air mixture. This outlet element or distributor mouthpiece 7 is interchangeably provided by being fastened to the nozzle body 3 with the aid of a quick-locking system, which can preferably be a bayonet fitting 9.

In the embodiment illustrated in FIGS. 1 and 2, the end of the nozzle body 3 facing away from the distributor mouthpiece 7 is provided with an outwardly open, central, axial threaded bore 10, on the bottom 10a of which the metering nozzle element 2 is loosely supported in such a way that its Nozzle opening is aligned coaxially to the central longitudinal axis 1a and to the immediately adjacent mixing chamber 5.

This metering nozzle element 2 is thus interchangeably received in the threaded bore 10 and fixed by a plug-like threaded adapter 11 provided with an external thread, which has a through bore 11a aligned coaxially with the longitudinal axis 1a of the nozzle and is provided with a union nut 12 at its end opposite the metering nozzle element 2, through which the entire injector nozzle 1 can be connected to a corresponding line (line system), not illustrated here, through which a liquid to be distributed is introduced under pressure.

As FIG. 1 also shows, there is a cavity between the mixing chamber 5 and the distributor mouthpiece 7, through which a homogenizing and calming space 13 is formed, the inlet cross-section of which (indicated approximately by the dash-dotted line 13a) jumps in relation to the outlet cross-section 5a of the mixing chamber 5 is enlarged. This inlet cross section 13a of the homogenizing and calming space 13 has approximately 1.5 to 9 times the value, preferably 3 to 5 times the value of the outlet cross section 5a of the mixing chamber 5.

As has already been mentioned above, the homogenizing and calming space 13 can be designed differently in accordance with the respective application requirements of the injector nozzle 1.

It can be seen in FIG. 1 that the homogenizing and calming space 13 can have an overall length L which is greater than the length of the mixing chamber 5. The homogenizing and calming space 13 has in this case a rear space area 13b, which surrounds the component 3a of the nozzle body 3 forming the mixing chamber 5 in a ring shape. It is also advantageous if between the end 3b of the nozzle body 3 pointing in the direction of flow (arrow 4) on the one hand and the inner end 7a of the distributor mouthpiece 7 or a corresponding shoulder 9a within the bayonet catch 9 on the other hand an annular sealing body 14 made of a suitable sealing or Buffer material is arranged, the interior of which also forms part of the homogenizing and calming space 13.

In the exemplary embodiment illustrated in FIG. 1, the mixing chamber 5, which extends coaxially to the longitudinal axis 1a of the nozzle, is designed in such a way that it widens conically towards the homogenizing and calming space 13, so that there is an overall design in the manner of the known Venturi system . In this case, the air intake opening 6 can be made approximately in the form of a radial bore and - viewed in the direction of flow (arrow 4) of the liquid jet - open into the rear, approximately cylindrically widened end 5b of the mixing chamber 5.

The interchangeable metering nozzle element 2 can also be designed in various ways. According to the exemplary embodiment in FIG. 1, it is assumed that it is designed to be self-centering. For this purpose, the front end 2b of the metering nozzle element 2 containing the nozzle opening 2a can be approximately conical and partially engage in the approximately cylindrical rear end 5b of the mixing chamber 5.

As far as the design of the distributor mouthpiece 7 is concerned, the outlet opening 8 provided therein can have any configuration suitable for the respective application of the injector nozzle 1 in order to give the emerging liquid-air mixture, for example, the shape of a flat jet, full cone, cone or the like.

3 to 7, a few further embodiments and variants of the injector nozzle according to the invention are first explained, and these embodiments relate in particular, but not only to the area of the homogenizing and calming space, while all other components of the injector nozzle - to the extent they are not specifically addressed - can be carried out essentially the same, as has been explained with reference to FIGS. 1 and 2.

In the example in FIG. 3, the homogenizing and calming space 13 'is of particularly large volume within the injector nozzle 1' and is designed with a spatial area 13'a which has a larger diameter than the other spatial areas of this homogenizing and calming space 13 '. This space region 13'a, which has an enlarged diameter, is provided approximately in the longitudinal section of the homogenizing and calming space 13 ', which surrounds the outlet cross section 5a of the mixing chamber 5, so that here a particularly large inlet cross section of the homogenizing and calming space 13' compared to the outlet cross section 5a the mixing chamber 5 is present. Here, too, the rear area 13b 'of this homogenizing and calming space 13' can surround the component 3a forming the mixing chamber 5 in a ring. At least the front area 13'c of the room 13 'can also expand slightly conically in the direction of flow (arrow 4) of the liquid jet.

An embodiment of the injector nozzle 1 ″ is illustrated in FIG. 4, the homogenizing and calming space 13 ″ of which can be designed similar to the homogenizing and calming space 13 ′ according to FIG. 3, with the exception that none (FIG. 4) there is an enlarged area in diameter. Rather, the homogenizing and calming space 13 '' according to FIG. 4 widens slightly conically over its entire length in the direction of flow (arrow 4).

According to the embodiments in FIGS. 5 and 6 of the injector nozzle 1 ″ ″ and 1 ″ ″, the homogenizing and calming space 13 formed therein can basically have the same design and arrangement, as has been explained in detail with reference to FIG. 1 . A peculiarity of these two embodiments can be seen in the fact that a perforated element is provided between the mixing chamber 5 and the distributor mouthpiece 7. This perforated element can be formed by a perforated plate 15 in the case of FIG. 5 and by a wire mesh or screen 16 in the case of FIG. In both embodiments (FIGS. 5 and 6), this perforated element 15 or 16 is installed in the annular sealing body 14. This perforated element 15 or 16 optimally ensures extremely good uniformity of the liquid droplet sizes.

Compared to the exemplary embodiment described and illustrated with reference to FIG. 1, the embodiment of the injector nozzle 1 ″ ″ in FIG. 5 has yet another Special feature insofar as there the metering nozzle element 2 ', which is in turn interchangeably arranged in the threaded bore 10 and fixed by the threaded adapter 11, can be embodied essentially in the form of a nozzle disk which is surrounded by an O-ring 17, which can consist of an elastic sealing material and aligns this metering nozzle element 2 'with its nozzle opening 2'a coaxial to the longitudinal axis 1''' a, whereby a kind of self-centering can also be achieved here.

7 shows an embodiment of the injector nozzle in which the homogenizing and calming space 13 '' '' 'between the mixing chamber 5 and the distributor mouthpiece 7 is kept particularly small in volume, but also an abrupt increase in its inlet cross section compared to that Has outlet cross section of the mixing chamber 5. In this case too, it is again assumed that a perforated element (preferably wire mesh 16 or perforated plate 15) is provided between the mixing chamber 5 and the distributor mouthpiece 7, which - similar to that in FIGS. 5 and 6 - can be installed in the annular sealing body 14 can. The advantages of the injector nozzle according to the invention can also be achieved with this embodiment, in which case a particularly compact, space-saving design is added.

Another special feature should be mentioned when designing the injector nozzle according to FIG. According to this, the air intake opening 6 can also be protected by a cover 18 which, as illustrated in FIG. 7, is preferably in the form of an annular diaphragm is, which covers a type of annular space or annular gap 18a and can also be integrated in a fastening nut or union nut in an axial extension of the sleeve-like fastening part 19 of the bayonet fitting 9 or in another embodiment of the quick-release system for the distributor mouthpiece 7. Such a cover 18 of the air intake opening 6 can possibly catch back flowing liquid particles, so that there a separate check valve with the associated operational disadvantages can be avoided in a simple manner.

With regard to the structural design in the area of the air intake opening 6, the exemplary embodiment illustrated in FIG. 4 will be discussed again. There is also a possibility of how the air intake opening 6 of the mixing chamber 5 can be connected to a device, preferably a throttle device 20, for changing the amount of air drawn in. This throttle device illustrated at 20 can of course also be formed by any other suitable device which permits a corresponding change or control of the amount of air to be drawn in.

With regard to these design options in the area of the air intake opening 6 previously explained with reference to FIGS. 7 and 4, it should be expressly emphasized that these design options not only apply to the exemplary embodiments of the injector nozzle with the special shapes of the homogenizing and calming space explained with reference to FIGS. 7 and 4 are connected, but that they also with all other described embodiments the injector nozzle according to the invention can be combined.

Finally, with reference to FIGS. 8 and 9, some possibilities for the configuration of the outlet element designed as a distributor mouthpiece are illustrated.

8 shows an embodiment of the distributor mouthpiece 7 'with a single outlet opening 8', which has a cross-section that can be adjusted in terms of shape and size. The latter can be achieved in that, for example in the area in front of this outlet opening 8 ', an adjusting perforated disk 21 can be provided in the manner of an adjusting diaphragm, which can either be rotated or shifted transversely or radially around the nozzle outlet opening 8' or its cross section in to adjust as desired.

FIG. 9 shows an exemplary embodiment in which the outlet element, which is again designed as a distributor mouthpiece 7 ″, has a plurality of outlet openings 8 ″, which can be aligned with one another in a divergent manner with respect to the longitudinal axis 1a of the nozzle.

Also with regard to these design options for the nozzle outlet opening or openings 8 'or 8' 'previously described with reference to FIGS. 8 and 9, it should be emphasized that these configurations of the distributor mouthpiece 7' or 7 '' with all other previously described embodiments the injector nozzle according to the invention can be combined.

Claims (17)

Injector nozzle for generating air-filled liquid drops containing a) a dosing nozzle element (2, 2 ') for generating a liquid jet, b) a mixing chamber (5), which follows the metering nozzle element in the flow direction (4) of the liquid jet and is provided with an air intake opening (6), for producing a liquid-air mixture c) and an outlet element (7) provided with at least one outlet opening (8) for the liquid-air mixture, characterized in that d) between the mixing chamber (5) and the outlet element (7) a homogenizing and calming space (13, 13 ', 13'',13''''') is provided, the inlet cross-section (13a) of which is abrupt compared to the outlet cross-section (5a ) of the mixing chamber (5) is enlarged. Injector nozzle according to Claim 1, characterized in that the inlet cross section (13a) of the homogenizing and calming space (13) is 1.5 to 9 times the value, preferably 3 to 5 times the value of the outlet cross section (5a) of the mixing chamber (5) having. Injector nozzle according to claim 1, characterized in that the homogenizing and calming space (13, 13 ', 13' ') has an overall length (L) which is greater than the length of the mixing chamber (5). Injector nozzle according to Claim 1, characterized in that the homogenizing and calming space (13, 13 ', 13' ') has a rear space area (13b, 13') which surrounds the component (3a) forming the mixing chamber (5) in a ring. Injector nozzle according to claim 1, characterized in that the homogenizing and calming space (13 ') has at least one spatial area (13'a) which has a larger diameter than the other spatial areas of the homogenizing and calming space. Injector nozzle according to claim 1, characterized in that between the mixing chamber (5) and the outlet element (7) there is a perforated element, preferably formed by a wire mesh (16) or a perforated plate (15). Injector nozzle according to one of the preceding claims, characterized in that the mixing chamber (5) widens conically towards the homogenizing and calming space (13). Injector nozzle according to one of the preceding claims, characterized in that the outlet element (7) can be replaced. Injector nozzle according to claim 8, characterized in that the outlet element (7) is fastened by means of a quick-lock system, preferably a bayonet lock (9). Injector nozzle according to one of the preceding claims, characterized in that the metering nozzle element (2, 2 ') can be replaced. Injector nozzle according to one of the preceding claims, characterized in that the metering nozzle element (2) is self-centering. Injector nozzle according to one of the preceding claims, characterized in that the outlet element (7 '') has a plurality of outlet openings (8 ''). Injector nozzle according to one of the preceding claims, characterized in that the outlet opening (8 ') of the outlet element (7') has a cross section which can be adjusted in terms of shape and size. Injector nozzle according to one of the preceding claims, characterized in that the air intake opening (6) of the mixing chamber (5) can be connected to a device, preferably a throttle device (20), for changing the amount of air drawn in. Injector nozzle according to one of the preceding claims, characterized in that the air intake opening of the mixing chamber is at an excess pressure Air system, preferably connected to the exhaust system of a carrier vehicle. Injector nozzle according to one of the preceding claims, characterized in that the air intake opening (6) of the mixing chamber (5) is protected by a cover (18), which is preferably formed by an annular screen which is inserted into a fastening part (19) of the quick-release system (9) for the outlet element (7) is integrated. Injector nozzle according to one of the preceding claims, characterized in that at least one further suction opening is provided for feeding further liquids and / or gases into the mixing chamber.

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