EP2595758B1 - Static spray mixer - Google Patents

Description

The invention relates to a static spray mixer for mixing and spraying of at least two flowable components according to the preamble of the independent claim.

Static mixers for mixing at least two flowable components are for example in the EP-A-0 749 776 and in the EP-A-0 815 929 described. Despite their simple, material-saving construction of their mixer structure, these very compact mixers produce good mixing results, especially when mixing highly viscous substances such as sealants, two-component foams, or two-component adhesives. Typically, such static mixers are designed for single use and are often used for curing products in which the mixer practically can not be cleaned.

In some applications where such static mixers are used, it is desirable to spray the two components onto a substrate after they have been mixed in the static mixer. For this purpose, the mixed components are atomized at the outlet of the mixer by exposure to a medium such as air and can then be applied in the form of a spray or spray on the desired substrate. With this technology, especially higher-viscosity coating media, for. As polyurethanes, epoxy resins or the like can be processed.

A device for such applications is for example in the US-B-6,951,310 disclosed. In this device, a tubular mixer housing is provided, which receives the mixing element for the static mixture and which has an external thread at one end, onto which an annular nozzle body is screwed. The nozzle body also has an external thread. On the end of the mixing element, which looks out from the mixer housing, a cone-shaped Zerstäuberelement is placed, which has on its conical surface a plurality of longitudinal grooves. About this Zerstäuberelement a cap is inverted, the inner surface is also designed conical, so that it rests against the conical surface of the atomizer. Consequently, the grooves form flow channels between the atomizer element and the cap. The cap is fixed together with the atomizer element by means of a union nut, which is screwed onto the external thread of the nozzle body, on the nozzle body. The nozzle body has a connection for compressed air. In operation, the compressed air flows from the nozzle body through the flow channels between the atomizer element and the cap and atomizes the material emerging from the mixing element.

Although this device has proven to be quite functional, so its structure is very complex and the assembly is complex, so that the device is not very economical, especially in terms of single use.

A structurally much simpler static spray mixer is described in the European patent application no. 09168285 Sulzer Mixpac AG. In this spray mixer, the mixer housing and the atomizing nozzle are each designed in one piece, wherein the grooves forming the flow channels are provided in the inner surface of the atomizing sleeve or in the outer surface of the mixer housing.

Starting from this prior art, it is an object of the invention to propose another static spray mixer for mixing and spraying at least two flowable components, which is economical to manufacture and allows efficient mixing and atomization of the components.

The object of the invention solving this object is characterized by the features of the independent claim.

Thus, according to the invention, static spray mixers for mixing and spraying at least two flowable components are proposed, having a tubular mixer housing which extends in the direction of a longitudinal axis to a distal end which has an outlet opening for the components, with at least one mixing element arranged in the mixer housing for mixing the components as well as with a sputtering sleeve, which has an inner surface, which encloses the mixer housing in its end region, wherein the sputtering sleeve having an inlet channel for a pressurized sputtering medium, wherein in the outer surface of the mixer housing or in the inner surface of the sputtering sleeve several each extending to the distal end extending grooves are formed between the sputtering sleeve and the mixer housing separate flow channels through which the sputtering medium from the inlet channel of atomization sleeve can flow to the distal end of the mixer housing. Each flow channel has in the flow direction in each case a changing inclination to the longitudinal axis.

By the measure, the slope of the flow channels over their course in the axial direction not to keep constant, but to change the Stömungsverhältnisse the Zerstäubungsmediums can be optimized so as to achieve a particularly uniform and stable exposure of the sputtering medium to the mixed components, from In particular, a higher reproducibility of the process results.

In addition, since the flow channels are provided in the mixer housing or in the atomizing sleeve, a particularly simple structure of the static spray mixer results, without concessions to the quality of mixing or atomization being necessary for this purpose. The optimal Use of the individual components enables a cost-effective and economical production of the spray mixers, which moreover can-at least largely-be carried out automatically. In principle, the inventive static spray mixer requires only three components, namely the one-piece mixer housing, the atomizer sleeve and the mixing element, which may also be configured in one piece. This results in a low complexity and ease of manufacture or assembly.

In a first preferred embodiment, the changing inclination of the flow channels is realized in that each groove seen in the flow direction has three successively arranged portions, wherein the central portion has a slope to the longitudinal axis, which is greater than the inclination of the two adjacent sections. It is particularly preferred if the central portion has an inclination to the longitudinal axis, which is greater than 45 ° and in particular less than 50 °.

In a second preferred embodiment, the changing inclination is realized by having each groove in the direction of flow having a portion in which the inclination to the longitudinal axis continuously changes. In this section, therefore, the bottom of the respective groove is designed curved, which can be achieved in particular by the fact that the inner surface of the atomizing sleeve or the outer surface of the mixer housing is formed curved in the direction of the longitudinal axis.

An advantageous measure is that the mixer housing has a distal end region, which tapers towards the distal end and in which the inner surface of the atomization sleeve is designed to cooperate with the distal end region. This rejuvenation improves the atomization effect.

Preferably, the outer surface of the mixer housing in the distal end region is at least partially designed as a frustoconical surface or as a curved surface in the axial direction in order to realize a particularly good interaction with the atomizing sleeve.

With regard to a uniform atomization, it has proved to be advantageous if the distal end of the mixer housing protrudes beyond the atomization sleeve.

In order to allow the greatest possible impact of the atomizing medium on the energy to be atomized components, the flow channels are preferably designed according to the principle of a Laval nozzle with a flow cross-section initially narrowing in the flow direction and then expanding. This measure results in an additional acceleration of the sputtering medium, for example on supersonic speed, resulting in the higher energy input.

An advantageous measure for realizing the principle of a Laval nozzle is that the grooves narrow in the direction of flow with respect to the circumferential direction. With the circumferential direction is meant the direction in which the inner surface of the atomizing sleeve or the outer surface of the mixer housing extends in the direction perpendicular to the longitudinal axis direction.

Such a narrowing can advantageously also be achieved in that each groove is delimited by two walls, of which at least one is curved in the direction of flow.

Furthermore, it is preferable if the extension of the grooves also has a component in the circumferential direction. As a result of this measure, the atomizing medium can be set into a rotational movement about the longitudinal axis as it flows through the flow channels. It has been found that this twist has a stabilizing effect on the exiting at the distal end of the mixer housing flow of the sputtering, which has an advantageous effect on a uniform and reproducible spraying.

One possible embodiment is that the grooves have a substantially spiral profile with respect to the longitudinal axis A.

In order in particular to simplify the production still further, it is advantageous if the sputtering sleeve is connected thread-free with the mixer housing, for example, the sputtering sleeve is fastened by means of a sealing snap connection to the mixer housing

With a view to realizing a stabilizing twist of the atomizing medium, it is particularly advantageous if the inlet channel is arranged asymmetrically with respect to the longitudinal axis. As a result of this measure, as the atomizing medium flows into the atomizing sleeve, a rotational movement is generated, from which a swirl of the atomizing medium results.

Preferably, the inlet channel opens into the inner surface of the atomizing sleeve perpendicular to the longitudinal axis.

Further advantageous measures and embodiments of the invention will become apparent from the dependent claims.

Fig. 1:

einen Längsschnitt eines ersten Ausführungsbeispiels eines erfindungsgemässen statischen Sprühmischers,

Fig. 2:

eine perspektivische Schnittdarstellung des distalen Endbereichs des ersten Ausführungsbeispiels,

Fig. 3:

eine perspektivische Darstellung der Zerstäubungshülse des ersten Ausführungsbeispiels,

Fig. 4:

einen Längsschnitt durch die Zerstäubungshülse des ersten Ausführungsbeispiels

Fig. 5:

eine perspektivische Darstellung des distalen Endbereichs des Mischergehäuses des ersten Ausführungsbeispiels ,

Fig. 6:

einen Querschnitt durch das erste Ausführungsbeispiel entlang der Schnittlinie VI-VI in Fig. 1,

Fig. 7:

einen Querschnitt durch das erste Ausführungsbeispiel entlang der Schnittlinie VII-VII in Fig. 1,

Fig. 8:

einen Querschnitt durch das erste Ausführungsbeispiel entlang der Schnittlinie VIII-VIII in Fig. 1,

Fig. 9:

einen Längsschnitt eines zweiten Ausführungsbeispiels eines erfindungsgemässen statischen Sprühmischers, analog zu Fig. 1

Fig. 10:

eine perspektivische Schnittdarstellung des distalen Endbereichs des zweiten Ausführungsbeispiels,

Fig. 11:

eine perspektivische Darstellung der Zerstäubungshülse des zweiten Ausführungsbeispiels,

Fig. 12:

eine perspektivische Darstellung des distalen Endbereichs des Mischergehäuses des zweiten Ausführungsbeispiels ,

Fig. 13:

einen Querschnitt durch das zweite Ausführungsbeispiel entlang der Schnittlinie XIII-XIII in Fig. 9,

Fig. 14:

einen Querschnitt durch das zweite Ausführungsbeispiel entlang der Schnittlinie XIV-XIV in Fig. 9,

Fig. 15:

einen Querschnitt durch das zweite Ausführungsbeispiel entlang der Schnittlinie XV-XV in Fig. 9.

In the following the invention will be explained in more detail by means of embodiments and with reference to the drawing. In the schematic drawing show partly in section:

Fig. 1:

a longitudinal section of a first embodiment of an inventive static spray mixer,

Fig. 2:

a perspective sectional view of the distal end portion of the first embodiment,

3:

a perspective view of the atomizing sleeve of the first embodiment,

4:

a longitudinal section through the atomizing sleeve of the first embodiment

Fig. 5:

a perspective view of the distal end portion of the mixer housing of the first embodiment,

Fig. 6:

a cross-section through the first embodiment along the section line VI-VI in Fig. 1 .

Fig. 7:

a cross section through the first embodiment along the section line VII-VII in Fig. 1 .

Fig. 8:

a cross section through the first embodiment along the section line VIII-VIII in Fig. 1 .

Fig. 9:

a longitudinal section of a second embodiment of an inventive static spray mixer, analogous to Fig. 1

Fig. 10:

a perspective sectional view of the distal end portion of the second embodiment,

Fig. 11:

a perspective view of the atomizing sleeve of the second embodiment,

Fig. 12:

a perspective view of the distal end portion of the mixer housing of the second embodiment,

Fig. 13:

a cross section through the second embodiment along the section line XIII-XIII in Fig. 9 .

Fig. 14:

a cross section through the second embodiment along the section line XIV-XIV in Fig. 9 .

Fig. 15:

a cross section through the second embodiment along the section line XV-XV in Fig. 9 ,

Fig. 1 shows a longitudinal section of a first embodiment of an inventive static spray mixer, which is generally designated by the reference numeral 1. The spray mixer is used for mixing and spraying of at least two flowable components. Fig. 2 shows one perspective view of the distal end portion of the first embodiment.

In the following, reference will be made to the case, which is particularly relevant for practice, in that exactly two components are mixed and sprayed. It is understood, however, that the invention can also be used for mixing and spraying more than two components.

The spray mixer 1 comprises a tubular, one-piece mixer housing 2 which extends in the direction of a longitudinal axis A to a distal end 21. By the distal end 21 is meant that end at which the mixed components leave the mixer housing 2 in the operating state. For this purpose, the distal end 21 is provided with an outlet opening 22. At the proximal end, meaning the end at which the components to be mixed are introduced into the mixer housing 2, the mixer housing 2 has a connecting piece 23, by means of which the mixer housing 2 can be connected to a reservoir for the components. This reservoir can be, for example, a known two-component cartridge, designed as a coaxial or side-by-side cartridge, or two tanks in which the two components are kept separate from each other. Depending on the configuration of the reservoir, or its output, the connector is designed, e.g. as a snap connection, as a bayonet connection, as a threaded connection or combinations thereof.

In the mixer housing 2, at least one static mixing element 3 is arranged in a manner known per se, which rests against the inner wall of the mixer housing 2, so that the two components can only pass through the mixing element 3 from the proximal end to the outlet opening 22. Either several, successively arranged mixing elements 3 may be provided, or as in the present embodiment, a one-piece mixing element 3, which is preferably injection molded and consists of a thermoplastic. Such static mixers or mixing elements 3 per se are well known to the person skilled in the art and therefore require no further explanation.

Particularly suitable are those mixers or mixing elements 3 such as those sold under the brand name QUADRO® by the company Sulzer Chemtech AG (Switzerland). Such mixing elements are for example in the already cited documents EP-A-0 749 776 and EP-A-0 815 929 described. Such a mixing element 3 of the Qudro® type has a rectangular, in particular a square cross section, perpendicular to the longitudinal direction A. Accordingly, the one-piece mixer housing 2, at least in the region in which it encloses the mixing element 3, a substantially rectangular, in particular square cross-sectional area perpendicular to the longitudinal axis A.

The mixing element 3 does not extend all the way to the distal end 21 of the mixer housing 2, but ends at a stop 25 (see Fig. 2 ), which is realized here by the transition of the mixer housing 2 from a square to a round cross-section. Seen in the direction of flow, therefore, the interior of the mixer housing 2 up to this stop 25 has a substantially square cross-section for receiving the mixing element 3. At this stop 25, the interior of the mixer housing 2 is in a circular cone shape, which realizes a taper in the mixer housing 2. Here, the interior thus has a circular cross section and forms an exit region 26, which tapers in the direction of the distal end 21 and there opens into the outlet opening 22.

The static spray mixer 1 further comprises a sputtering sleeve 4 having an inner surface which encloses the mixer housing 2 in its end region. The atomizing sleeve 4 is designed in one piece and is preferably injection-molded, in particular made of a thermoplastic. It has an inlet channel 41 for a pressurized atomizing medium, which is in particular gaseous. Preferably, the atomization medium is compressed air. The inlet channel 41 can be designed for all known connections, in particular also for a Luer lock.

In order to allow a particularly simple assembly or production, the atomizing sleeve 4 is preferably connected thread-free with the mixer housing, in the present embodiment by means of a Snap connection. For this purpose, a flange-like elevation 24 is provided on the mixer housing 2 (see Fig. 2 ), which extends over the entire circumference of the mixer housing 2. On the inner surface of the atomizing sleeve 4, a circumferential groove 43 is provided, which is designed to cooperate with the survey 24. If the atomizing sleeve 4 is pushed over the mixer housing 2, the projection 24 snaps into the circumferential groove 43 and ensures a stable connection of the atomizing sleeve 4 to the mixer housing 2. Preferably, this snap connection is designed to be sealing, so that the atomizing medium - in this case not the compressed air can escape through this from the circumferential groove 43 and the survey 24 existing connection. Furthermore, the atomizing sleeve 4 lies with its inner surface in a region between the mouth of the inlet channel 41 and the elevation 24 closely on the outer surface of the mixer housing 2, so that also a sealing effect is achieved, which prevents leakage or a reverse flow of the atomizing medium.

Of course, it is also possible to arrange additional sealing means, for example an O-ring, between the mixer housing 2 and the atomizing sleeve 4.

Alternatively to the illustrated embodiment, it is also possible to provide a circumferential groove on the mixer housing 2 and on the atomizing sleeve 4 a survey, which engages in this circumferential groove.

Preferably, the connection between the atomizing sleeve 4 and the mixer housing 2 is designed such that the atomizing sleeve 4 connected to the mixer housing 2 is rotatable about the longitudinal axis A. This is ensured for example in a snap connection with the fully circumferential circumferential groove 43 and the survey 24. The rotatability of the atomizing sleeve 4 has the advantage that the inlet channel 41 can always be aligned so that it can be connected as simply as possible to a source for the atomizing medium.

In the outer surface of the mixer housing 2 or in the inner surface of the atomizing sleeve 4, several are each to the distal end 21st extending grooves 5 are provided, which form separate flow channels 51 between the sputtering sleeve 4 and the mixer housing 2, through which the sputtering medium from the inlet channel 41 of the sputtering sleeve 4 to the distal end 21 of the mixer housing 2 can flow. In the embodiment described here, the grooves 5 are provided in the inner surface of the atomizing sleeve 4, they can of course also be provided in a similar manner analogously or in addition in the outer surface of the mixer housing 2.

The grooves 5 may be curved, for example, arcuate or rectilinear or may be configured by combinations of curved and rectilinear sections.

For a better understanding of the course of the grooves 5 shows Fig. 3 another perspective view of the atomizing sleeve 4 of the first embodiment, wherein the view into the atomizing sleeve 4 takes place in the flow direction. In Fig. 4 is a longitudinal section through the atomizing sleeve 4 is shown

According to the invention, each flow channel 51 or the associated grooves 5 is formed such that, viewed in the flow direction, it has in each case a changing inclination to the longitudinal axis A. In the first embodiment, this is realized so that each groove 5 seen in the flow direction comprises three consecutively arranged sections 52, 53, 54 (see also Fig. 3 and Fig. 4 ), wherein the central portion 53 has an inclination α ₂ to the longitudinal axis A, which is greater than the inclination α ₁ , α _{3 of} the two adjacent sections 52 and 54. In sections 52, 53 and 54, the inclination of the grooves 5 with respect the longitudinal axis A respectively constant. In the first section 52 seen in the flow direction, which is adjacent to the mouth of the inlet channel 41, the inclination α _{1 may} also be zero (see Fig. 4 ), that is, this section 52 may extend in the direction of the longitudinal axis A seen parallel to the longitudinal axis A. Thus, in the sections 53, 54 and optionally also in the first section 52, the bottom of each groove 5 is part of a conical or truncated cone surface, wherein the cone angle α ₂ in the central portion 53 is greater than the cone angle α ₁ , α ₃ in the adjacent sections 52 and 54. In the first As already mentioned, section 52 can also be zero in relation to the longitudinal axis; In this case, the grooves 5 in this first section 52 are each part of a cylindrical surface, the angle α ₁ has the value 0 °. In the middle section 53, which has the greatest inclination with respect to the longitudinal axis A, the inclination α _{2 is} preferably greater than 45 ° and less than 50 °. In the embodiment described here, the inclination is α ₂ against the longitudinal axis A in the middle section 46 °. In the first section 52, the inclination α ₁ here is 0 °. In the third section 54, which lies at the distal end 21, the inclination α ₃ egen the longitudinal axis A is preferably less than 20 °, in the present example, it is about 10 ° to 11 °.

Each of the grooves 5 is bounded laterally by two walls, which are formed by ribs 55, which are each arranged between two adjacent grooves 5. How this particular out Fig. 3 and Fig. 4 As can be seen, change these ribs 55 seen in the direction of flow their height H, which means their extension in the direction perpendicular to the longitudinal axis A radial direction. The ribs begin in the region of the mouth of the inlet channel 41 and in the first section 52 with a height of zero and then rise continuously until they have reached their maximum height in the central portion 53.

Fig. 5 shows a perspective view of the distal end portion 27 of the mixer housing 2 with the distal end 21. The distal end portion 27 of the mixer housing 2 tapers toward the distal end 21. In the first exemplary embodiment, the distal end region 27 is conical and comprises two successively arranged regions, namely an upstream flat region 271 and a steeper region 272 adjoining it means in the areas 271 and 272, the outer surface of the mixer housing 2 is configured in each case as a frustoconical surface, wherein the measured against the longitudinal axis cone angle of the flat portion 271 is smaller than the measured against the longitudinal axis A cone angle of the steeper region 272. The function of this structural measure explained further below.

Alternatively, it is also possible that the flat portion 271 is configured with a cone angle of 0 °, that is, the flat portion 271 is then cylindrical. The outer surface of the mixer housing 2 is then in the flat region 271, the lateral surface of a cylinder whose cylinder axis coincides with the longitudinal axis A.

Like that too Fig. 1 shows that sticks out in Fig. 5 illustrated distal end 21 of the mixer housing 2 on the sputtering 4 also.

In order to make the exact course of the grooves 5 of the first embodiment even clearer are in addition to the Fig. 3 and 4 in the Fig. 6-8 in each case a cross section perpendicular to the longitudinal axis A shown, in Fig. 6 along the section line VI-VI in Fig. 1 ; in Fig. 7 along the section line VII-VII; and in Fig. 8 along the section line VIII-VIII in Fig. 1 ,

The inner surface of the atomizing sleeve 4 is configured to cooperate with the distal end portion 27 of the mixer housing 2. The provided between the grooves 5 ribs 55 of the atomizing sleeve 4 and the outer surface of the mixer housing 2 are close and sealing to each other so that the grooves 5 in the respective separate flow channel 51 between the inner surface of the Zerstäubungshülse 4 and the outer surface of the mixer housing 2 form (see Fig. 6 ).

Further upstream, in the region of the mouth of the inlet channel 41 (see also Fig. 4 ), the height H of the ribs 55 is so small that an annular space 6 exists between the outer surface of the mixer housing 2 and the inner surface of the atomizer sleeve 4. The annular space 6 is in fluid communication with the inlet channel 41 of the atomizer sleeve 4. Through the annular space 6, the sputtering medium can pass from the inlet channel 41 into the separate flow channels 51. The height H of the ribs 55 within the annular space 6 is not necessarily everywhere zero. As this particular from the Fig. 4 and 8th It can be seen that all or some of the ribs 55 in the annular space 6 still have a different height from zero H, so that they protrude with respect to the vertical axis to the longitudinal axis A radial direction into the annulus, but without touching the outer surface of the mixer housing 2 in this area.

The grooves 5, in this embodiment, eight grooves 5, are evenly distributed over the inner surface of the atomizing sleeve 4. It has proved to be advantageous with regard to the most complete and homogeneous atomization of the mixed components emerging from the outlet opening when the compressed air flows generated by the grooves 5 have a twist, ie a rotation on a helix about the longitudinal axis A. This twist causes a clear stabilization of the compressed air flow. The circulating atomizing medium, in this case compressed air, generates a jet which is stabilized by the swirl and thus acts evenly on the mixed components emerging from the outlet opening 22. This results in a very uniform and in particular reproducible spray pattern. Particularly favorable in this case is a possible cone-shaped compressed air jet, which is stabilized by the spin. This extremely uniform and reproducible air flow results in significantly lower overspray during use.

The emerging at the distal end 21 of the respective separate flow channels 51 individual compressed air jets (or jets of Zerstäubungsmediums) are initially formed at their exit as discrete individual jets, which then unite due to their swirl attachment to a uniform stable overall jet, which emerges from the mixer housing dcem mixed components atomized. This total jet preferably has a conical shape.

To generate the swirl in the flow of atomizing medium, several measures are provided. The grooves 5, which form the flow channels 51, do not extend exactly in the axial direction defined by the longitudinal axis A or inclined not only on the longitudinal axis, but the extension of the grooves 5 also has a component in the circumferential direction of the atomizing sleeve 4. Dies is particular from the illustration in Fig. 3 and in Fig. 6 seen. In addition to the inclination against the longitudinal axis A, the course of the grooves 5 is at least approximately helical or helical about the longitudinal axis A. Another measure that supports the formation of the twist is realized by the design of the ribs 55 which the walls of the Form grooves 5. Like this best Fig. 3 and Fig. 7 can be seen, the ribs 55 are formed so that, at least in the central portion 53, one of the two walls, each defining the grooves 5 laterally, viewed in the flow direction curved or designed by a polygon approximately curved. The respective other wall is formed linearly but extends obliquely to the longitudinal axis A, that they each have a component in the circumferential direction. Due to the curvature of one wall, the generation of the twist can be positively influenced.

Another measure for generating the twist, which is also completely independent of the other design of the static spray mixer can be realized, is to arrange the inlet channel 41, through which the sputtering medium enters the flow channels 51, asymmetrically with respect to the longitudinal axis A. This measure is best in the Fig. 8 to recognize. The inlet channel 41 has a central axis Z. The inlet channel 41 is arranged so that its central axis Z does not intersect the longitudinal axis A, but has a vertical distance e from the longitudinal axis A. This asymmetric or even eccentric arrangement of the inlet channel 41 with respect to the longitudinal axis A has the consequence that the atomizing medium, in this case the compressed air, when entering the annular space 6 in a rotational or swirling motion about the longitudinal axis A is added. Preferably, the inlet channel 41 is as in Fig. 8 shown - arranged that it opens perpendicular to the longitudinal axis A in the inner surface of the atomizing sleeve 4. Of course, such embodiments are possible in which the inlet channel 41 opens at an angle different from 90 °, ie obliquely to the longitudinal axis A.

In order to increase the energy input from the sputtering medium to the exiting from the outlet opening 22 components, it is a particularly advantageous measure to design the flow channels 51 according to the principle of a Laval nozzle with a first narrowing in the flow direction and then expanding flow cross-section. In order to realize this narrowing of the flow cross section, two dimensions are available, namely the two directions of the plane perpendicular to the longitudinal axis A. One direction is referred to as a radial direction, which on the longitudinal axis A is meant perpendicular direction, which has radially outward from the longitudinal axis A. The other direction is referred to as the circumferential direction, which means the direction which is perpendicular both in the direction defined by the longitudinal axis A and in the radial direction. The extent of the flow channels 51 in the radial direction is referred to as their depth.

With regard to the radial direction, the principle of the Laval nozzle can be realized in that in the middle steep section 53, the depth of the flow channels 51 in the flow direction decreases sharply. The depth becomes minimal where the mixer housing 2 makes the transition from the flat area 271 to the steeper area 272. Downstream of this transition, the depth of the flow channels 51 increases again, mainly due to the fact that here the outer surface of the mixer housing 2 part of a steeper truncated cone and the inclination of the inner surface of the Zerstäubungshülse 4 in the third section 54 remains substantially constant. By this measure can be achieved with respect to the radial direction of the effect of a Laval nozzle.

Additionally or alternatively, the flow channels 51 may also be configured with respect to the circumferential direction according to the principle of a Laval nozzle. This is best in the presentation of Fig. 3 to recognize. The grooves 5 are designed in the central portion 53 so that they narrow in the flow direction with respect to the circumferential direction. This is realized in that the walls of the grooves 5 formed by the ribs 55 do not run parallel for each groove 5, but the one wall extends to the other, so that a reduction of the extent of the groove 5 in the circumferential direction. As already mentioned above, in the exemplary embodiment described here, the one wall is formed linearly in each groove 5, while the other wall is designed curved in the flow direction in such a way that the flow channel 51 narrows with respect to the circumferential direction.

Due to the design of the grooves 5 and the flow channels 51 according to the principle of a Laval nozzle, the air used as a sputtering medium can also be additionally with downstream even the narrowest point Apply kinetic energy and thus accelerate. As with a Laval nozzle, this happens through the flow cross-section widening again in the direction of flow. This results in a higher energy input into the components to be atomized. In addition, the beam is stabilized by this realization of the lavaline principle. The diverging, that is again widening opening of the respective flow channel 51 also has the positive effect of avoiding or at least a significant reduction of fluctuations in the beam.

In operation, this first embodiment operates as follows. The static spray mixer is connected by means of its connecting piece 23 to a storage vessel containing the two components separated from each other, for example with a two-component cartridge. The inlet channel 41 of the atomizing sleeve 4 is connected to a source of the atomizing medium, for example a compressed air source. Now the two components are discharged, get into the static spray mixer 1 and are intimately mixed there by means of the mixing element 3. As homogeneously mixed material, the two components, after flowing through the mixing element 3, pass through the outlet region 26 of the mixer housing 2 to the outlet opening 22. The compressed air flows through the inlet channel 41 of the atomizing sleeve 4 into the annular space 6 between the inner surface of the atomizing sleeve 4 and the outer surface of the mixer housing 2 , Obtained by the asymmetric arrangement a twist and passes from there through the grooves 5, which form the flow channels 51, to the distal end 21 and thus to the outlet opening 22 of the mixer housing 3. Here, the stabilized by the swirl compressed air flow meets the through the outlet opening 22 exiting mixed material, atomizes it evenly and transports it as a spray to the substrate to be treated or coated. Since in some applications the discharge of the components from the storage vessel takes place with compressed air or compressed air, the compressed air can also be used for the atomization.

An advantage of the static spray mixer 1 according to the invention can be seen in its particularly simple construction and production. In principle, only three parts are required in the exemplary embodiment described here, namely, a one-piece mixer housing 2, a one-piece mixing element 3 and a one-piece atomizing sleeve 4, wherein each of these parts can be produced in a simple and economical manner by injection molding. The particularly simple design also allows for - at least largely - automated assembly of the parts of the static spray mixer 1. In particular, no screwing these three parts are necessary.

With regard to a particularly simple and cost-effective production, it is advantageous if the mixer housing and / or the atomizing sleeve are injection-molded, preferably made of a thermoplastic.

For the same reason, it is advantageous if the mixing element is configured in one piece and injection-molded, preferably of a thermoplastic.

The following is based on the Fig. 9-15 A second embodiment of the inventive static spray mixer explained. In this case, only the essential differences in comparison with the first embodiment will be discussed. In the second embodiment, the same or functionally equivalent parts are given the same reference numerals as in the first embodiment. The explanations given with respect to the first exemplary embodiment and the measures and variants explained with reference to the first exemplary embodiment also apply analogously to the second exemplary embodiment.

Fig. 9 shows a longitudinal section of the second embodiment, analogous to Fig. 1 , Fig. 10 shows a perspective sectional view of the distal end portion of the second embodiment. In Fig. 11 is analogous to Fig. 3 a perspective view of the atomizing sleeve 4 is shown, wherein the view takes place in the flow direction in the Zerstäubungshülse inside. Fig. 12 shows in one too Fig. 5 analog representation of the distal end portion 27 of the mixer housing. In order to make the exact course of the grooves 5 of the second embodiment even clearer is in addition to Fig. 11 in the Fig. 13-15 in each case a cross section perpendicular to the longitudinal axis A shown, in Fig. 13 along the section line XIII-XIII in Fig. 9 ; in Fig. 14 along the line XIV-XIV; and in Fig. 15 along the section line XV-XV in Fig. 9 ,

In the second embodiment, the changing inclination of the flow channels 51 to the longitudinal axis A is realized by a continuous change. For this purpose, the atomizing sleeve 4 has a portion 56 (see Fig. 11 ), in which the inclination of the grooves 5 in the direction of flow changes continuously. For this purpose, the inner surface of the atomizing sleeve 4 is curved at least in the section 56 in the flow direction, so that here the inclination of the grooves 5 changes continuously.

For generating or for amplifying the twisting movement, the flow channels 51 extend helically about the longitudinal axis A, their extent in the circumferential direction in the section 56 decreasing in the direction of flow.

Fig. 12 shows a perspective view of the distal end portion 27 of the mixer housing 2 with the distal end 21. The distal end portion 27 of the mixer housing 2 tapers toward the distal end 21. In the second exemplary embodiment, the distal end region 27 is configured as part of an ellipsoid of revolution, ie, in addition to the curvature in the circumferential direction, a curvature is also provided in the axial direction defined by the longitudinal axis A. The two successively arranged in the direction of the longitudinal axis A arranged areas, namely the upstream flat portion 271 and the subsequent steeper area 272. are each curved in the axial direction, that is, in the areas 271 and 272 is the outer surface of the mixer housing. 2 each configured as a partial surface of an ellipsoid of revolution, wherein the curvature of the flat portion 271 is smaller than the curvature of the steeper region 272. This can be realized in the second embodiment, the principle of a Laval nozzle with respect to the radial direction in the interaction of the mixer housing 2 and the Zerstäubungshülse.

Claims (15)

1. A static spray mixer (1) for the mixing and spraying of at least two flowable components having a tubular mixer housing (2) which extends in the direction of a longitudinal axis (A) up to a distal end (21) which has an outlet opening (22) for the components, having at least one mixing element (3) arranged in the mixer housing (2) for the mixing of the components as well as having an atomization sleeve (4) which has an inner surface which surrounds the mixer housing (2) in its end region (27), wherein the atomization sleeve (4) has an inlet channel (41) for a pressurized atomization medium, wherein a plurality of grooves (5) are provided in the outer surface of the mixer housing (2) or in the inner surface of the atomization sleeve (4) which respectively extend toward the distal end (21) and which form separate flow channels (51) between the atomization sleeve (4) and the mixer housing (2) through which the atomization medium can flow from the inlet channel (41) of the atomization sleeve (4) to the distal end (21) of the mixer housing (2), characterized in that each flow channel (51) has a respective changing inclination toward the longitudinal axis (A) in the direction of flow.
2. A static spray mixer in accordance with claim 1, wherein each groove (5) has three sections (52, 53, 54) arranged after one another, viewed in the direction of flow, with the middle section (53) having an inclination toward the longitudinal axis (A) which is larger than the inclination of the two adjacent sections (52, 54).
3. A static spray mixer in accordance with claim 2, wherein the middle section (53) has an inclination toward the longitudinal axis (A) which is larger than 45°.
4. A static spray mixer in accordance with any one of the preceding claims, wherein each groove (5) has a section (56), viewed in the direction of flow, in which the inclination toward the longitudinal axis (A) changes continuously.
5. A static spray mixer in accordance with any one of the preceding claims, wherein the mixer housing (2) has a distal end region (27) which tapers toward the distal end (21) and wherein the inner surface of the atomization sleeve (4) is configured for cooperation with the distal end region (27).
6. A static spray mixer in accordance with claim 5, wherein the outer surface of the mixer housing (2) is configured at least partly as a frustoconical surface or as a surface curved in the axial direction in the distal end region (27).
7. A static spray mixer in accordance with any one of the preceding claims, wherein the distal end (21) of the mixer housing (2) projects beyond the atomization sleeve (4).
8. A static spray mixer in accordance with any one of the preceding claims, wherein the flow channels (51) are configured in accordance with the principle of a Laval nozzle having a flow cross-section first narrowing and subsequently widening, viewed in the direction of flow.
9. A static spray mixer in accordance with any one of the preceding claims, wherein the grooves (5) narrow with respect to the peripheral direction, viewed in the direction of flow.
10. A static spray mixer in accordance with any one of the preceding claims, wherein each groove (5) is bounded by two walls of which at least one is configured as curved, viewed in the direction of flow.
11. A static spray mixer in accordance with any one of the preceding claims, wherein the extent of the grooves (5) also has a component in the peripheral direction.
12. A static spray mixer in accordance with any one of the preceding claims, wherein the grooves (5) have a substantially spiral extent with respect to the longitudinal axis (A).
13. A static spray mixer in accordance with claim 1, wherein the atomization sleeve (1) is connected in a thread-free manner to the mixer housing (2).
14. A static spray mixer in accordance with any one of the preceding claims, wherein the inlet channel (41) is arranged asymmetrically with respect to the longitudinal axis (A).
15. A static spray mixer in accordance with any one of the preceding claims, wherein the inlet channel (4) opens into the inner surface of the atomization sleeve (4) perpendicular to the longitudinal axis (A).

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