Nozzle attachment assembly

Abstract

The invention relates to a nozzle attachment assembly (10) comprising a connection element (12) with a coupling point (18) arranged on an end side (16), wherein a jet forming element (22) adjoins the connection element (12) along an axial extension direction (24) of the nozzle attachment assembly, and a jet maintaining element (14) adjoins the jet forming element (22), wherein the jet maintaining element (14) comprises, on an outlet side (26) facing away from the end side (16), an outlet opening (28) which is fluidically connected to the coupling point (18) through the interior of the nozzle attachment assembly (10), wherein the fluidic connection is formed, in the region of the jet maintaining element (14), as an expansion zone (30) which is delimited in a first plane perpendicular to the axial extension direction (24) by cover walls (34, 36) that exhibit a spacing h, and which is delimited in a second plane, which is perpendicular to the first plane, by side walls (40, 42), such that the expansion zone (30) overall simulates a jet geometry of the jet forming element (22) in such a way that a liquid jet formed by the jet forming element (22) is surrounded continuously by an encircling gap within the expansion zone (30) in a radial direction (46) perpendicular to the axial direction (24), and wherein the connection element (12) and / or the jet forming element (22) and / or the jet maintaining element (14) has at least one gas inlet opening (50) which leads into the expansion zone (30).

Description

[0001] NOZZLE ATTACHMENT ASSEMBLY

[0002] The present invention relates to a nozzle attachment assembly.

[0003] The present invention is explicitly based on the findings and disclosure of German patent application DE 10 2023 114 472, to which reference is made herein. The disclosure described therein is compatible with the present invention and can be combined with the present invention in terms of its features.

[0004] Liquid-powered high-pressure cleaners are well-known and are used, for example, for cleaning dirty surfaces or removing varnish and paint residue from surfaces. For this purpose, a high-pressure compressor pumps liquid under high pressure to an outlet nozzle, from which the liquid exits the high-pressure cleaner. The jet emerges in a shape determined by the nozzle. The liquid is often water or water mixed with a cleaning agent. Starting from the nozzle, the liquid jet then moves towards the surface to be cleaned, with the kinetic energy stored in the liquid particles of the liquid jet exerting its cleaning effect upon impact with the surface to be cleaned.

[0005] To enable the fastest possible cleaning of a surface, it is generally advantageous if the jet used is a flat jet. However, a suitable nozzle is not always available to generate a suitable flat jet. The reshaping of an already formed liquid jet, for example, a round or point jet, is already known and is described, for example, in DE 29 06 648 C3, where two plates are pivoted laterally into an already formed jet to create a flat jet with a variable geometry.

[0006] The problem here is that the jet shaping causes a high loss of efficiency and that the transferable kinetic energy and thus the cleaning performance of the liquid jet decreases with the increasing distance between the jet shaping element used and the surface to be cleaned. This effect is already noticeable when cleaning in air because, despite its comparatively low density, air impedes the movement of the liquid jet and leads to a noticeable dispersion of the liquid jet after just a few centimeters. This is particularly true, however, when cleaning is to take place in a significantly denser / more viscous medium. If the liquid jet is used underwater to clean a surface, for example, a noticeable reduction in cleaning performance can be seen even after the liquid jet has to travel significantly shorter distances to the surface to be cleaned (compared to air).

[0007] To date, this problem has been solved by regularly increasing the kinetic energy stored in the water jet by using more powerful compressors to provide the required cleaning performance in the respective application, or by using a nozzle that already generates the desired jet geometry, thus avoiding jet reshaping and the associated losses. However, this approach has its economic and technical limitations.

[0008] The present invention is based on the object of providing a cost-effective and energy-efficient jet transformation for a liquid-operated high-pressure cleaning system.

[0009] This object is achieved by means of a nozzle attachment assembly having the features of independent claim 1. Advantageous embodiments and further developments emerge from the dependent claims.

[0010] A nozzle attachment assembly is described comprising a connecting element with a coupling point arranged on a front side for receiving a nozzle of a liquid-operated high-pressure cleaner or for spatially fixing the nozzle attachment assembly with respect to a liquid jet generated by the nozzle, wherein a jet-shaping element is connected to the connecting element along an axial extension direction of the nozzle attachment assembly, and a jet-preserving element is connected to the jet-shaping element, wherein the jet-preserving element comprises an outlet opening on an outlet side facing away from the front side, which outlet opening is in fluid-conducting connection through the interior of the nozzle attachment assembly with the coupling point, wherein the fluid-conducting connection in the region of the jet-preserving element is formed as an expansion zone which is delimited by cover walls in a first plane perpendicular to the axial extension direction,which have a distance h and which are delimited by side walls in a second plane which is perpendicular to the first plane, so that the expansion zone as a whole simulates a jet geometry of the jet-shaping element such that a liquid jet formed by the jet-shaping element is continuously surrounded by a circumferential gap within the expansion zone in a radial direction perpendicular to the axial extension direction, and wherein the connecting element and / or the jet-shaping element and / or the jet-preserving element has at least one gas inlet opening which opens into the expansion zone.

[0011] In this way, a fully formed liquid jet that has left a nozzle of a liquid-powered high-pressure cleaning system can be efficiently reshaped to suit a specific application. This eliminates the need for the laborious provision of separate nozzles that must be adapted to each specific application. The combination of jet-shaping element and jet-preserving element, which are fixed to the existing nozzle by means of the coupling element, enables the efficient use of this nozzle for a modified application. The at least one gas inlet opening can, as required, be equipped with a filter or shielding device to prevent the ingress of foreign particles or dirt that could negatively impact gas intake. The outlet opening can be essentially rectangular, but can also have slightly rounded corners.In particular, the two short sides can also be slightly curved. The ratio of the short sides to the long sides of the outlet opening can, for example, be at least 1:10. The expansion zone can accompany the expansion of the liquid jet, for example, by a factor of 20 (in jet width) along the axial extension direction, i.e., from the outlet of the flat jet nozzle to the outlet opening of the nozzle attachment assembly.

[0012] The distance h can be constant or at least essentially constant. However, it is also possible for the distance h between the two cover walls to increase or decrease in the axial direction of extension as seen from the flat nozzle, whereby the increase and decrease can be identified by an opening or closing angle. In this context, the increase or decrease can occur in particular uniformly, so that a plane of symmetry can be found in which the axial direction of extension can run. The opening or closing angle can preferably be constant.Such a variation of the distance h or the provision of an opening / closing angle can, if required, cause additional jet shaping in the expansion zone behind the actual jet shaping element, since these changes initially cause a change in the uniformity of the gas flow and, as a direct consequence, in turn a change in the jet preservation.

[0013] With the help of this nozzle attachment assembly, when coupled to a nozzle forming any liquid jet, for example, a point or round jet nozzle, the geometry of the emerging liquid jet can be adapted to the geometry specified by the jet-shaping element and the jet-preserving element. The rigid combination of jet-shaping element and jet-preserving element eliminates the need for a precise alignment of the liquid jet to the jet-preserving element (with regard to entry direction and point), which can be difficult to achieve. Using the described nozzle attachment assembly, the jet geometry of the (formed) liquid jet is advantageously maintained over a longer distance after exiting the nozzle attachment assembly, which is achieved with the help of the jet-preserving element.The term "distance" refers, for example, to the distance from the nozzle at which the liquid jet is generated by the nozzle, at which the "liquid" is currently being viewed. In particular, the typical scattering / atomization of the liquid jet by the medium, such as water or air, through which it passes can be significantly reduced, even after forming, using the provided jet containment element. This effect is achieved with the help of the gas, which can enter or be drawn into the expansion zone via the gas inlet opening.Due to its design, the liquid jet essentially does not touch the expansion zone as it passes through the jet containment element and is, if necessary, evenly spaced circumferentially in a radial direction from the top and side walls bordering the expansion zone, creating a circumferential gap of essentially constant width between the liquid jet and an expansion zone wall. The liquid jet flowing through the expansion zone draws in gas through the gas inlet opening based on the principle of a water jet pump (or suction jet pump). This gas enters the expansion zone and is entrained by the liquid jet.A uniform gas flow forms around the liquid jet in the gap between the surface of the liquid jet and the top and side walls of the expansion zone. This gas flow completely envelops the liquid jet even after it exits the outlet opening and advantageously delays the dispersion of the formed liquid jet after it exits the outlet opening. The generated uniform gas flow thus prevents or delays unwanted atomization or "thickening" of the liquid jet generated by the jet-shaping element during the expansion of the jet in the nozzle attachment assembly. The term "uniform" can be understood, for example, but is not limited to, a gas flow that has at least some properties of a laminar gas flow or a vortex-free gas flow.The term "thickening" can be used to describe a fanning out of the liquid jet, which intensifies or at least continues with the distance traveled. Due to the operating principle, the sucked-in gas is not sucked into the liquid jet, but rather accelerated on its surface in the direction of liquid flow. Although part of the kinetic energy contained in the liquid jet is used to suck in the gas, and the liquid jet is therefore even somewhat slower when it flows out of the nozzle attachment assembly (compared to a (constructively identical) system without a nozzle attachment assembly, which generates a liquid jet with the same geometry as the nozzle attachment assembly), a higher cleaning performance is achieved due to the better focusing of the liquid jet on the surface to be cleaned.A portion of the kinetic energy extracted from the liquid jet remains in the liquid jet in the form of (waste) heat. Experimentally, a measured warming of the liquid jet by 1 to 2°C was observed in the test system used with the described nozzle attachment assembly. This temperature increase, in turn, benefits the increased cleaning performance, as warmer liquids generally clean better than colder ones. By using the described nozzle attachment assembly, energy and liquid savings of 50% each can be achieved (based on cleaning performance) compared to a conventional system (which generates a liquid jet with the same geometry as the nozzle attachment assembly). At the same time, the greatly increased cleaning performance also allows for a significant amount of labor time to be saved.Furthermore, damage to surfaces to be cleaned can be avoided, as the more homogeneous liquid jet does not include any undesired areas with higher power. Because the nozzle attachment assembly completely predetermines the liquid jet in its geometry and orientation upon entry into the jet retention element by means of the jet-shaping element, a complex and precise alignment of the nozzle attachment assembly with respect to the original liquid jet is no longer necessary. The radial direction, in this case, refers particularly in cylindrical coordinates to a radial vector that is perpendicular to the axial extension direction (of the nozzle attachment assembly) and locally rotated by a rotation angle. <p gedreht werden kann und dabei in jeder Winkelposition senkrecht zu der axialen Erstreckungsrichtung steht.

[0014] Usefully, the jet-shaping element can be provided with a free flow volume that is bounded in the radial direction by an inner surface, wherein the inner surface forms a baffle for the liquid jet emerging from the nozzle. In this way, the outer geometry of the liquid jet impinging on the baffle can be subsequently modified upon passing through the jet-shaping element, wherein the geometry of the liquid jet after passing through the jet-shaping element is independent of the geometry of the original liquid jet.

[0015] Furthermore, it can be provided that the impact baffle is circumferentially delimited by a first self-contained contour line at a first end of the beam-shaping element, which faces the connecting element, and is delimited by a second self-contained contour line at a second end of the beam-shaping element, which faces the beam-preserving element, wherein surface elements lie between the two self-contained contour lines, which define flat surface sections of the inner surface between these two contour lines or which define at least partially curved surface sections of the inner surface, and whose respective surface section normals each have a non-vanishing component which points inwards in the radial direction and counter to the axial extension direction.In this way, a completely defined beam transformation can be achieved, whereby the term "completely defined" describes in particular that the transformation takes place or is defined on all sides.

[0016] The first contour line may be substantially circular. The term "substantially" generally refers to manufacturing-related tolerances. A circular first contour line enables particularly efficient introduction / absorption of a point or circular beam into the beam-shaping element.

[0017] Furthermore, the second contour line can be substantially rectangular. Here, too, the term "substantially" generally refers to manufacturing-related tolerances. A rectangular second contour line enables efficient transformation of the beam entering the beam-shaping element into a flat beam with a thickness and / or maximum width specified by the rectangle.

[0018] Usefully, the inner surface of the impact baffle extending between the two contour lines can be divided along a sectional plane into two opposing inner surface sections, such that these can be aligned by means of a reflection at the sectional plane and a shift in the axial direction of extension. In this way, a spatial and temporal offset of the deformation of an "upper" and a "lower" jet half can be achieved. This can result in efficiency advantages during jet deformation, as simultaneous "compression" (condensation of the flow) from the top and bottom toward the center of the intended jet geometry is avoided.

[0019] It can also be provided that an area encompassed by the second contour line within the nozzle attachment assembly defines an absolute areal narrow section of the fluid-conducting connection. Furthermore, it can be provided that the second contour line forms a separation edge for a liquid jet formed by the jet-shaping element. In this way, a defined separation of the liquid jet at the end of the jet-shaping element within the nozzle attachment assembly can be ensured.

[0020] Advantageously, the impact baffle can be designed to be interchangeable. This allows the nozzle attachment assembly to be adapted to various nozzles that provide differently shaped liquid jets without having to modify the entire nozzle attachment assembly.

[0021] The present invention is described below by way of example using preferred embodiments.

[0022] They show:

[0023] Figure 1 shows a first external view of a nozzle attachment assembly;

[0024] Figure 2 shows a second external view of the nozzle attachment assembly of Figure 1 from a different angle;

[0025] Figure 3 shows a first external view of an alternative nozzle attachment assembly;

[0026] Figure 4 shows the alternative nozzle attachment assembly shown in Figure 3 in a first sectional view;

[0027] Figure 5 shows the nozzle attachment assembly shown in Figure 3 in a second sectional view; Figure 6 shows the nozzle attachment assembly shown in Figures 1 and 2 in a first sectional view;

[0028] Figure 7 is a sectional view of another alternative nozzle attachment assembly;

[0029] Figure 8 is a detailed view of the section of the nozzle attachment assembly from Figure 6;

[0030] Figure 9 shows a further detailed view of a nozzle attachment assembly; and

[0031] Figure 10 is a further sectional view of the nozzle attachment assembly shown in Figure 3 from a different angle.

[0032] In the following drawings, like reference numerals designate like or similar components.

[0033] Figures 1 and 2 show a nozzle attachment assembly 10 from the outside from various angles. The nozzle attachment assembly 10 shown has an end face 16 with a coupling point 18 on the inlet side. The coupling point 18 can optionally serve to accommodate a nozzle 20 of a liquid-operated high-pressure cleaner or to spatially fix the nozzle attachment assembly 10 with respect to a liquid jet generated by a spaced-apart nozzle 20. In the figure, the nozzle 20 is not yet shown aligned with the nozzle attachment assembly 10. The area of ​​the nozzle attachment assembly 10 directly adjacent to the end face 16, which is referred to below as a connection element 12, can accordingly also be referred to as a spacer element.

[0034] Starting from the connecting element 12, the nozzle attachment assembly 10 extends in an axial direction of extension 24. A jet retention element 14 is provided at an end region of the nozzle attachment assembly 10 opposite the connecting element 12 in the axial direction of extension 24. As can be seen in particular in Figure 1, the jet retention element 14 has an outlet opening 28 on an outlet side 26, which can in particular be rectangular. A liquid jet passing through the nozzle attachment assembly 10 can emerge from the outlet opening. The emerging liquid jet can in particular be designed as a flat jet, wherein the thickness and width of the liquid jet are each less than the height and width of the outlet opening 28, so that the liquid jet does not come into contact with the edges of the outlet opening 28. The functioning of the jet retention element 14 will be explained in more detail below.

[0035] Also shown in Figure 2 is a radial direction 46, which in cylindrical coordinates denotes a radial vector which is perpendicular to the axial extension direction 24 and locally by an angle of rotation <p gedreht werden kann und dabei in jeder Winkelposition senkrecht zu der axialen Erstreckungsrichtung 24 steht.

[0036] Between the connecting element 12 and the jet retention element 14, the nozzle attachment assembly 10 comprises a jet shaping element 22 which cannot be seen in detail from the outside. The possible structure of the jet shaping element 22 is explained in more detail below in connection with the various sectional views of the nozzle attachment assembly 10.

[0037] On the end face 16 of the connecting element 12 of the nozzle attachment assembly 10, visible in Figure 2, a number of gas inlet openings 50 are visible, particularly circumferentially around the coupling point 18, through which gas, in particular air, can be sucked in in order to keep the liquid jet formed by the jet-shaping element 22 stable in its shape in the jet-preserving element 14. The gas inlet openings continue within the nozzle attachment assembly 10 in the form of gas channels, through which gas, in particular air, is sucked in from the liquid jet flowing through the nozzle attachment assembly according to the functional principle of a suction jet pump. The specific positioning of the gas inlet openings 50 on the end face 16 is optional.In particular, more or fewer individual gas inlet openings 50 can be arranged at different positions distributed over the nozzle attachment assembly 10, wherein only the gas channels running inside the nozzle attachment assembly 10 need to be adapted.

[0038] For example, Figure 3 shows a first external view of an alternative nozzle attachment assembly 10. In contrast to the nozzle attachment assembly 10 previously known from Figures 1 and 2, the nozzle attachment assembly 10 shown externally in Figure 3 shows that the gas inlet openings 50 are arranged directly on the jet retention element 14, and the jet retention element 14 appears significantly flatter. This is due to the fact that the alternative nozzle attachment assembly 10 shown in Figure 3 does not require any gas guide channels to thicken the jet retention element 14, since the gas in the area of ​​the jet retention element 14 can be sucked in directly from the outside by the liquid jet flowing past. Further differences between the two nozzle attachment assemblies shown in Figures 1 to 3 are not directly visible from the outside.

[0039] Figures 4 and 10 show sectional views of the alternative nozzle attachment assembly 10 shown from the outside in Figure 3 from different angles along a sectional plane 58. Visible, this time from the inside out, is the distribution of the gas inlet openings 50 on the jet preserving element 14. Between the jet preserving element 14 and the connecting element 12, the area of ​​the jet shaping element 22 is also marked by dashed lines in Figures 4 and 10. The entire nozzle attachment assembly 10 can be manufactured in one piece or integrally as a single component, with the connecting element 12, jet shaping element 22, and jet preserving element 14 adjoining one another in this order along the axial extension direction and being so firmly connected to one another that they cannot be separated from one another without destruction. However, a detachable connection between the individual elements can also be provided.For example, the jet-shaping element 22 can be designed as a baffle insert 56 that is detachable from the remaining components of the nozzle attachment assembly 10. The baffle insert 56 can, for example, have a frustoconical outer shape and can be inserted into the nozzle attachment assembly 10 from the connection element 12 along the axial extension direction 24. The baffle insert 56 can, if necessary, protrude beyond the actual area of ​​the jet-shaping element 22 in the axial extension direction 24, for example, to ensure secure fixation within the nozzle attachment assembly 10. In this way, a baffle 38 in the baffle insert 56 can be adapted to different nozzles or different liquid jet geometries without having to redesign the entire nozzle attachment assembly 10.

[0040] In the area of ​​the beam-shaping element 22, the aforementioned impact baffle 38 is provided, which lies between a first contour line 48 and a second contour line 52. The first contour line 48 represents a closed circumferential line at the end of the beam-shaping element 22 pointing towards the connecting element 12, whereby in Figures 4 and 10 only a lower half of the actually self-contained first contour line 48 is visible. Accordingly, at the opposite end of the beam-shaping element 22 there is the second contour line 52, which is also a self-contained contour line. In Figures 4 and 10, only one half of the two contour lines 48, 52 can be seen in each case due to the sectional view in the sectional plane 58. Between the two contour lines 48, 52 there extends a passage which narrows in the axial extension direction 24 of the nozzle attachment assembly and which is delimited by an inner surface 32.The inner surface 32 ultimately extends between the two self-contained contour lines 48, 52. The part of the inner surface 32 onto which the liquid jet to be reshaped ultimately impacts is referred to as the impact baffle 38. The impact baffle 38 reshapes the impinging jet according to the geometry of the second contour line 52, which forms a separation edge 54 for the passing liquid jet. Ultimately, it can be determined that in the region of the second contour line 52, the cross-section through which the liquid jet can flow forms a constriction, in particular an absolute constriction, in the nozzle attachment assembly 10.

[0041] The effect achieved by the jet-preserving element on the liquid jet formed by the jet-shaping element can be described as follows: The liquid jet emerging from the jet-shaping element draws in gas, particularly air, as it flows past the gas inlet openings. The drawn-in gas is distributed in the expansion zone of the nozzle attachment assembly, which is located in the jet-preserving element, forming a sliding layer between the formed liquid jet, which can particularly be a flat jet, and the side walls of the jet-preserving element. This optimizes the flowing liquid jet formed by the jet-shaping element.Optimization can be understood in particular as both compaction (e.g., in the sense of focusing the liquid jet) and homogenization (e.g., in the sense of equalizing the energy contained in the liquid jet). After the liquid jet has been optimized and thus preserved, the optimized liquid jet is then ejected from the nozzle attachment assembly. This is also the point at which the reshaped liquid jet exits the used nozzle attachment assembly.

[0042] The inner surface 32, or the impact baffle 38, visible in Figures 4 and 10 as part of the inner surface 32, which extends between the two contour lines 48, 52, is formed from individual surface sections, which together form a curved inner surface 32 or a curved impact baffle 38. The curvature of the impact baffle 38 or the inner surface 32 serves to deform the liquid jet impinging on the impact baffle 38 as efficiently as possible, i.e. with minimal energy loss. At the same time, with the aid of the optionally curved impact baffle 38, a comparatively homogeneous liquid jet can be generated, which already exhibits a high degree of dimensional stability along its flow direction.

[0043] During the forming process, the already fully formed (original) liquid jet, which will generally already be surrounded by air on all sides and was previously generated by the (external) nozzle 20, strikes the impact baffle 38, so that due to the low compressibility of the impinging liquid, a spatial deflection of the volume flow occurs according to the shape predetermined by the impact baffle 38. The second contour line 52 will generally circumscribe a substantially rectangular area and, on each of its longer sides, provide a separation edge 54 for the formed liquid jet. In the region of the separation edge 54, the formed liquid jet completely separates from the inner surface of the nozzle attachment assembly 10 and is thus once again surrounded on all sides by at least a thin layer of air when it enters the jet containment element 14.In the jet-shaping element 22, an original liquid jet is converted into a reshaped liquid jet at the impact gate 38. The jet-preserving element 14 then creates a sliding layer of sucked-in air around the reshaped liquid jet, as already described above. This can stabilize the external shape of the liquid jet emerging from the jet-preserving element 14 over a certain period of time / distance, which ultimately benefits the cleaning performance when it impacts a distant surface.

[0044] Figure 5 shows a further sectional view of the nozzle attachment assembly 10 already known from Figures 4 and 10, but now with the visible sectional plane set perpendicular to the previously used sectional plane 58. The jet-shaping element 22, which forms the inner surface 32 between the two closed contour lines 48, 52, is again clearly visible. Furthermore, at the end of the connecting element 12 facing the jet-shaping element 22, gas inlet openings opening towards the interior are also visible, through which gas, in particular air, can be drawn in by the liquid jet striking the impact baffle 38, based on the principle of a suction jet pump. This gas then flows laterally through the jet-shaping element 22 alongside the transforming liquid jet in the areas where the liquid jet does not strike the impact baffle 38.In the axial direction of extension 24 behind the jet-shaping element 22, i.e. in the jet-preserving element 14, the formed liquid jet is separated on all sides by a (thin) gas layer from the inner wall of the nozzle attachment assembly downstream of the separation edge 54 and, according to the principle of a suction jet pump, sucks in further gas at the gas inlet openings 50 as it flows past them.

[0045] Figures 6, 8 and 9 each show sections through the nozzle attachment assembly shown from the outside in Figures 1 and 2, with Figures 8 and 9 showing detailed views of the area of ​​the jet-shaping element 22. In contrast to the previously described embodiment of the jet-shaping element 22, in the jet-shaping element 22 shown in Figures 6, 8 and 9, the impact baffle 38, i.e. the part of the inner surface 32 between the two closed contour lines 48, 52, against which the liquid jet bounces and is thereby (re)shaped, is formed by opposing flat surfaces which are not curved in themselves. The opposing surfaces can be selected to be optimized with regard to their respective angle of attack relative to the axial extension direction 24.In particular, it can also be provided that the two opposing surfaces have different angles of attack. Furthermore, it can be provided that the liquid jet to be reshaped impinges on the two surfaces in unequal proportions, particularly at different angles of attack, and is accordingly reshaped unequally. This can be understood in particular to mean that more of the liquid jet to be reshaped impinges on and is reshaped on one of the two flat surfaces. The flat surface on which more of the liquid jet to be reshaped impinges on and is reshaped can in particular be the one with a lower / smaller angle of attack.The different angles of attack and the uneven distribution of the impinging liquid quantity can be coordinated in such a way that the deformation of the liquid jet in the jet-forming element 22 does not generate a force component that deviates from the axial direction of extension 24, which might have to be compensated for by a user.

[0046] In Figures 6 and 7, a structure can be seen in the area of ​​the jet containment element 14, in which the sucked-in gas, in particular air, is guided from the gas inlet openings 50 within the nozzle attachment assembly 10. This structure represents the previously mentioned gas channels. Cover walls 34, 36 are provided inside the jet containment element 14, between which the liquid jet flows, separated from each other by a gas layer.

[0047] Figure 7 shows a section through an alternative nozzle attachment assembly 10, in which a displacement 60 along the axial direction 24 of surface portions of the inner surface 32 or the impact gate 38 that are opposite one another along the sectional plane is visible. In this way, jet shaping in the jet-shaping element 22 is performed spatially and temporally offset on the opposite sides of the liquid jet flowing through the jet-shaping element 22 in the axial extension direction 24, which can be advantageous with regard to energy losses occurring within the liquid jet.

[0048] The features of the invention disclosed in the above description, in the drawings, and in the claims may be essential for the realization of the invention, both individually and in any combination. List of reference symbols

[0049] 10 Nozzle attachment assembly

[0050] 12 connecting element

[0051] 14 Beam preservation element

[0052] 16 Front side

[0053] 18 coupling point

[0054] 20 nozzle

[0055] 22 Beam shaping element

[0056] 24 axial extension direction

[0057] 26 Exhaust side

[0058] 28 Outlet opening

[0059] 30 Expansion Zone

[0060] 32 inner surface

[0061] 34 Ceiling wall

[0062] 36 Ceiling wall

[0063] 38 impact backdrop

[0064] 40 side wall

[0065] 42 side wall

[0066] 46 radial direction

[0067] 48 first contour line

[0068] 50 Gas inlet opening

[0069] 52 second contour line

[0070] 54 tear-off edge

[0071] 56 Impact splitter insert

[0072] 58 cutting plane

[0073] 60 displacement h distance

Claims

Claims 1. Nozzle attachment assembly (10) comprising a connecting element (12) with a coupling point (18) arranged on an end face (16) for receiving a nozzle (20) of a liquid-operated high-pressure cleaner or for spatially fixing the nozzle attachment assembly (10) with respect to a liquid jet generated by the nozzle (20), wherein a jet-shaping element (22) adjoins the connecting element (12) along an axial extension direction (24) of the nozzle attachment assembly (10), and a jet-preserving element (14) adjoins the jet-shaping element (22), wherein the jet-preserving element (14) comprises an outlet opening (28) on an outlet side (26) facing away from the end face (16), which outlet opening is in fluid-conducting connection with the coupling point (18) through the interior of the nozzle attachment assembly (10), wherein the fluid-conducting Connection in the region of the beam preservation element (14) is designed as an expansion zone (30),which is delimited in a first plane perpendicular to the axial extension direction (24) by cover walls (34, 36) which have a distance h and which is delimited in a second plane perpendicular to the first plane by side walls (40, 42), so that the expansion zone (30) as a whole simulates a jet geometry of the jet-shaping element (22) such that a liquid jet formed by the jet-shaping element (22) within the expansion zone (30) is continuously surrounded by a circumferential gap in a radial direction (46) perpendicular to the axial extension direction (24), and, wherein the connecting element (12) and / or the beam-shaping element (22) and / or the beam-preserving element (14) has at least one gas inlet opening (50) which opens into the expansion zone (30).

2. Nozzle attachment assembly (10) according to claim 1, wherein the jet shaping element (22) has a free flow volume which is delimited in the radial direction (46) by an inner surface, the inner surface (32) forming an impact baffle (38) for the liquid jet emerging from the nozzle (20).

3. Nozzle attachment assembly (10) according to claim 2, wherein the impact gate (38) is circumferentially delimited by a first self-contained contour line (48) at a first end of the jet-shaping element (22) facing the connecting element (12) and is delimited by a second self-contained contour line (52) at a second end of the jet-shaping element (22) facing the jet-preserving element (14), wherein surface elements lie between the two self-contained contour lines (48, 52) which define flat surface sections of the inner surface (32) between these two contour lines (48, 52) or which define at least partially curved surface sections of the inner surface (32), and whose respective surface section normals each have a non-vanishing component which points inwards in the radial direction (46) and counter to the axial extension direction (24).

4. Nozzle attachment assembly (10) according to claim 3, wherein the first contour line (48) is substantially circular.

5. Nozzle attachment assembly (10) according to claim 3 or 4, wherein the second contour line (52) is substantially rectangular.

6. Nozzle attachment assembly (10) according to one of claims 2 to 5, wherein the inner surface (32) of the impact gate (38) extending between the two contour lines (48, 52) can be divided along a cutting plane (58) into two opposing inner surface parts in such a way that these can be made to coincide with one another by means of a reflection at the cutting plane (58) and a displacement (60) in the axial extension direction (24).

7. Nozzle attachment assembly (10) according to one of claims 3 to 6, wherein an area encompassed by the second contour line (52) within the nozzle attachment assembly (10) defines an area-absolute constriction of the fluid-conducting connection.

8. Nozzle attachment assembly (10) according to one of claims 3 to 7, wherein the second contour line (52) forms a separation edge (54) for a liquid jet formed by the jet-shaping element (22).

9. Nozzle attachment assembly (10) according to one of claims 2 to 8, wherein the impact gate (38) is designed to be replaceable.

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