MIXER

Description

[0001] The invention relates to a mixer for mixing pasty and / or flowable components. In particular, the invention relates to a static mixer, i.e., a mixer in which the components to be mixed are not mixed by an actively driven mixing element, but rather flow past a mixing element and are mixed in the process.

[0002] Such mixers are used, among other things, for mixing reacting components, especially those that harden, including in the dental field. These components are typically stored in containers or chambers of a cartridge to which the mixer can be attached, either permanently or as a removable part. As the components are dispensed from the cartridge containers, they pass through the mixer and emerge mixed.

[0003] Examples of such mixers are known from EP 0 815 929 B1, EP 1 125 626 B1, EP 1 312 409 B1, EP 1 588 757 B1, EP 2 133 138 B1, EP 2 599 540 A1, EP 2 301 656 B1, WO 2011 / 119820 A1, US 2017 / 0 036 179 A1 and EP 1 426 099 B1.

[0004] DE 10 2006 047 811 A1 describes a multi-component cartridge with a permanently connected mixing element and a discharge tube, wherein the mixing element is designed as a guide element for the axial displacement of the discharge tube.

[0005] EP 0 815 929 B1 discloses a mixer with a mixing sleeve extending along a longitudinal axis and having at least two inlets and one outlet. The mixer further comprises a mixing element housed within the mixing sleeve, which, together with the mixing sleeve, defines several chambers arranged one behind the other and / or next to each other along a flow path from the inlets to the outlet. The chambers are bounded by transverse walls extending perpendicular to the longitudinal axis and by four side walls extending parallel to the longitudinal axis. Adjacent chambers are connected to each other via through-openings provided in the side walls. However, the described mixers are sometimes difficult to manufacture using injection molding. Furthermore, it has been shown that the flow of the components to be mixed along the side walls has a detrimental effect on the mixing result.

[0006] With this known mixer, depending on the components to be mixed, an unsatisfactory mixing result can occur if, for example, streaks of individual components permeate the entire mixer and exit the outlet essentially unmixed.

[0007] To improve the mixing result and prevent unmixed areas, EP 2 301 656 B1 proposes the use of first and second flow sections. While the first flow sections guide the components from the center to the outer areas of the mixing element, the second flow sections guide the components from the outer areas to the center of the mixing element. These flow sections are intended to reverse the flow direction of some of the components, but are extremely complex to manufacture.

[0008] EP 2 614 883 A1 also describes a static mixer which exhibits an improved mixing result. For this purpose, in addition to deflection elements, so-called release elements are arranged on the radially outer sides of the mixing element, with the release elements pointing radially inwards.

[0009] From EP 2 133 138 B1 a mixer is known which has a first series of mixing elements for dividing the component flows in a first direction and a second series of mixing elements for dividing the component flows in a second direction.

[0010] A mixer known from EP 1 125 626 B1 has several modifications of a rectangular basic structure of mixing chambers, which have inlets and outlets. One modification has a web inclined to the pipe axis, which connects an inlet to an outlet in a mixing chamber such that the flow is deflected by the web from the pipe wall towards the pipe axis or vice versa. Alternatively, the lengths of three adjacent chambers can be shortened, thus reducing the number of inlets or outlets. The three modified chambers formed in this way are arranged such that a pair of chambers, arranged one behind the other along the pipe axis, form two of these chambers, and a third chamber, arranged laterally to the chamber pair, connects the two chambers of the pair via two openings.

[0011] The aforementioned mixers feature highly complex mixing elements designed to address the problem of streaking, making them correspondingly complex and expensive to manufacture. Therefore, such mixers are only conditionally suitable for applications where the mixed components harden and the mixer is thus used as a disposable product.

[0012] A mixer according to the preamble of claim 1 is known from US 2001 / 015936 A1.

[0013] Based on this, it is an object of the present invention to provide a mixer of the type described above which has a simple structure and enables thorough mixing of pasty and / or flowable components.

[0014] This problem is essentially solved by a mixer according to claim 1. The mixer has, in particular cuboid, chambers arranged one behind the other and next to each other, which are connected to each other via through-openings. Along a flow path from the inlets to the outlet, i.e., along the path of the components through the mixer, the components flow through some of the chambers and are thereby mixed together.

[0015] According to a first aspect of the present invention, the mixing element comprises two strips, each forming, in particular substantially closed, side walls, which extend, in particular parallel to or converging towards each other, at a distance from one another in the direction of the longitudinal axis of the mixer. The strips are connected by a web that forms further side walls and is arranged perpendicular to the strips. The strips preferably form radially, i.e., projecting laterally from the central or center of gravity and the longitudinal axis of the mixer, outer side walls of the chambers, which can abut the inner wall of the mixing sleeve. In contrast, the web, as a separating element extending parallel to the longitudinal axis, can divide the mixing chamber of the mixing sleeve into two areas.The strips and the web are preferably arranged relative to each other to form an H-shaped cross-section (perpendicular to the longitudinal axis), with the web connecting the strips, in particular, at their midpoints. This basic structure of the mixing element, consisting of two strips and a web, is relatively easy and cost-effective to manufacture, for example, using injection molding. At the same time, this design results in a relatively rigid and stable mixing element, which facilitates its installation in the mixing sleeve.

[0016] A first group of chambers, also called chambers of the first group, has primary through-openings arranged in the web that extend to the strips, and a second group of chambers, also called chambers of the second group, has secondary through-openings positioned at a distance from both strips in the web. In other words, the primary through-openings extend to a radially outer region of the mixing chamber formed by the mixing sleeve, defined by one of the strips, whereas the secondary through-openings, due to their arrangement at a distance from both strips, are radially offset inwards within the mixing chamber. This different arrangement of the through-openings effectively prevents streaks of the components to be mixed from passing unmixed through the outer region of the mixing chamber to the outlet.In particular, the first through-openings can be designed such that they extend, optionally interrupted by a further side wall, across the entire width of the mixing chamber from one of the strips to the other. According to the invention, the second through-openings are designed such that they extend, at a distance from both strips and again optionally interrupted by a further side wall, across a radially inner region of the mixing chamber.

[0017] Preferably, the transverse walls are connected to the web and one of the strips. According to one embodiment, the transverse walls do not extend across the entire width of the web, but, for example, only from one of the strips to the center of the web. This closes off approximately one quarter of the cross-section of the mixing chamber in the direction of the longitudinal axis. Transverse walls can be provided on both sides of the web in one cross-sectional plane of the mixer, i.e., at the same position along the longitudinal axis. It is preferred that the transverse walls are arranged offset from each other, i.e., one transverse wall extends on one side of the web from one of the strips to the center of the mixing chamber, and another transverse wall extends on the other side of the web from the other strip to the center.

[0018] Further side walls of the chambers can extend from the transverse walls towards the inlets, i.e., against the flow direction of the components, parallel to the strips. These further side walls are preferably arranged centrally on the web to further subdivide the halves of the mixing chamber divided by the web into, for example, quarters of the mixing chamber. Preferably, in this design of the mixing element, one of the through-openings in the web is provided in the area along the longitudinal axis where these further side walls are located. Conversely, for example, through-openings are provided in the further side walls in the area along the longitudinal axis where the web is closed.

[0019] According to a preferred embodiment, the chambers of the first group and the chambers of the second group each have exactly four through-openings, two of which are formed in the web and two further through-openings run parallel to the web in the other side walls, so that, in particular, the through-openings running parallel to the web create a flow direction parallel to the web. In other words, in these chambers, the through-openings, which are preferably all arranged offset from one another along the longitudinal axis, are arranged in directions perpendicular to the longitudinal axis and to each other.This allows the components to mix as they enter each chamber from chambers located in different quadrants (viewed in a cross-section perpendicular to the longitudinal axis) and as they exit each chamber into chambers located in different quadrants (viewed in a cross-section perpendicular to the longitudinal axis). Specifically, the two openings formed in the web are provided as recesses in the web, while the two additional openings running parallel to the web can be provided as recesses in the walls running perpendicular to the web.

[0020] Some known mixers suffer from the problem that at the beginning of the mixing process, one of the components enters the mixing chamber too quickly or in too large a quantity, so that the initial quantity of the mixture does not contain the desired mixing ratio of the components. This problem can be addressed, among other things, by having the mixing sleeve and the mixing element form a third group of at least one chamber, which, as a reservoir chamber, has closed side walls and only one opening, formed as an inlet opening in a transverse wall. An initial quantity of the components flowing into the mixer can be collected in this reservoir chamber, so that only subsequent quantities of the components, which then usually have the correct mixing ratio, are mixed in the mixer and discharged from it.Since the storage chamber according to the invention has only one inlet opening, but is otherwise not connected to the other chambers by flow, the components entering the storage chamber are held there, so that they essentially no longer participate in the further mixing process.

[0021] It has proven particularly advantageous to provide at least one buffer chamber at the inlet end of the mixing element. In this configuration, the leading component is not first guided through other chambers. In the division of the mixing chamber into four quadrants (viewed in a cross-section perpendicular to the longitudinal axis) as described above, two quadrants, offset from each other, can be equipped with buffer chambers, while the other two quadrants contain chambers of the first or second group.

[0022] The mixing sleeve and the mixing element preferably each form four chambers arranged side by side in cross-section, which are at least partially offset from each other in the direction of the longitudinal axis. In principle, however, more than four chambers can also be arranged side by side.

[0023] The mixing sleeve can have a first section with a rectangular cross-section, in which the mixing element is housed, and a second section with a circular cross-section, on which the outlet is provided. The end of the mixing sleeve, which can be connected to a cartridge, for example, can also have a circular cross-section. This cartridge-side section can be provided with connecting means for attaching the mixer to the cartridge, for example, bayonet fittings or a thread, in particular an external threaded section.

[0024] Preferably, the mixing sleeve has an inlet section in which an insert, having at least two nozzles forming the inlets, is axially sealed and fixed. The seal of the insert against the mixing sleeve can be such that the insert is pressed more firmly into the mixing sleeve as the dispensing pressure increases. Alternatively, circumferential lips can be provided which, depending on the internal pressure in the mixer, form a tighter seal against a sealing surface. If the insert is freely rotatable relative to the mixing sleeve, the nozzles of the insert can engage with corresponding nozzles or openings of the cartridge without hindering any relative rotation of the mixing sleeve that may be necessary for attaching the mixer to the cartridge.

[0025] Preferably, the nozzles of the insert are flow-connected to the chambers via channels that form at least one compensation chamber and / or extend radially inwards, at least in sections. The arrangement and design of the channels can thus also contribute to solving or minimizing the problem described above for known mixers with a component that initially leads the flow.

[0026] If necessary, several first groups of chambers and several second groups of chambers can be arranged in the mixing element. It has proven particularly advantageous to provide one to three first groups and one to three second groups of chambers in the mixing element.

[0027] It is further preferred to arrange the first group of chambers and the second group of chambers in the upper and / or middle region of the mixing element, viewed in the dispensing direction of the components. In other words, the first and second groups of chambers are arranged in the region above 50% or above 70% of the axial length of the mixing element, again viewed in the dispensing direction of the components. Particularly preferred are the first and second groups of chambers arranged in the region between 50% and 95% of the length of the mixing element, again viewed in the dispensing direction of the components.

[0028] It is further preferred if the mixing element has a flow chamber adjacent to the storage chamber, wherein the flow chamber has a through-opening running parallel to the web. In particular, it is preferred if the cross-section of the flow chamber perpendicular to the material discharge direction is 80% to 120% of the cross-section of the through-opening of the flow chamber. This improves the flow behavior of the components in the area of ​​the storage chamber and the flow chamber, as it prevents an increased pressure build-up in the area of ​​the through-opening. For this purpose, the overall length of the mixer, or sections thereof, can be adjusted in the material discharge direction, which affects the cross-section of the through-opening. In particular, the overall length of the mixer can be increased, which also increases the cross-section of the through-opening.

[0029] Alternatively or in addition, the barrier chamber can also be shortened in the material discharge direction, which also increases the cross-section of the passage opening.

[0030] Extending this idea, the flow chamber can be designed to be bounded by a transverse wall in the material discharge direction, and this transverse wall can include an opening so that the components can flow at least partially through the opening. This reduces the discharge pressure when the components are discharged by the mixer, resulting in improved ease of use during discharge.

[0031] It is further preferred that the cross-section of the mixing element perpendicular to the longitudinal axis in the section of the storage chamber and / or flow chamber is 105% to 150%, preferably 105% to 120%, and particularly preferably 110% ± 5%, of the cross-section of the mixing element perpendicular to the longitudinal axis in the subsequent section of the mixing element, viewed in the material discharge direction. In other words, the mixing element is enlarged in a region of the storage chamber and / or flow chamber. This allows for a larger flow cross-section in this region while maintaining the same stability of the mixing element, which is advantageous for reducing discharge pressures, especially with highly viscous components. Furthermore, the storage capacity of the storage chamber is improved, enabling the intake of a large volume of feed material.

[0032] The storage chamber and / or flow chamber are preferably provided in the section that overlaps with the inlet section of the mixing sleeve. This has the advantage that a widening of the mixing element can be accommodated in this section by appropriately adapting the inner contour of the inlet section of the mixing sleeve. Alternatively, the mixing sleeve itself can, of course, be adapted to the widened contour of the mixing element.

[0033] The invention is explained in more detail below with reference to exemplary embodiments and the drawings. All features described and / or illustrated, whether individually or in any combination, constitute the subject matter of the invention, irrespective of their compilation in the claims or their cross-references.

[0034] They show schematically: Figure 1a shows the individual parts of a mixer according to a first embodiment in side view, Figure 1b shows the individual parts of the mixer according to Figure 1a In another side view, Figure 1c, the individual parts of the mixer are shown. Figure 1a in perspective view, Figure 2aden mixer after Figure 1a in sectional view, Figure 2b the mixer after Figure 1a in another sectional view, Figure 2c the mixer after Figure 1a Top view, Figure 3 in perspective view, components of the mixer according to Figure 1a with enlarged details, Figure 4a a mixing element of a mixer according to a second embodiment of the invention in perspective view, Figure 4b the mixing element according to Figure 4a in sectional view, Figure 5 a perspective view of a mixer with a third mixing element, an insert and a mixing sleeve, Figures 6a to 6c a perspective view ( Figure 6a ), a side view (Figure 6b) and a longitudinal section ( Figure 6c) along the section plane AA of a fourth mixing element, Figure 7a to 7c a perspective view ( Figure 7a ) and a side view ( Figure 7b ) and a longitudinal section ( Figure 7c ) along the section plane BB of a fifth mixing element, Figure 8a to 8ce a perspective view ( Figure 8a ) and a side view ( Figure 8b ) and a longitudinal section ( Figure 8c ) along the section plane CC of a sixth mixing element, Figure 9a to 9ce a perspective view ( Figure 9a ) and a side view ( Figure 9b ) and a longitudinal section ( Figure 9c ) along the section plane DD of a seventh mixing element, Figure 10a to 10ce a perspective view ( Figure 10a ) and a side view ( Figure 10b ) and a longitudinal section ( Figure 10c ) along the section plane EE of an eighth mixing element, and Figures 11a to 11ce show a perspective view ( Figure 11a ) and a side view ( Figure 11b ) and a longitudinal section ( Figure 11c) along the section plane FF of a ninth mixing element.

[0035] The first embodiment according to the Figures 1a to 3 The static mixer shown is essentially made up of three components: a mixing sleeve 1, a mixing element 2 and an insert 3.

[0036] The mixing sleeve 1 is an elongated component that extends along a longitudinal axis L. The mixing sleeve 1 has a [missing information] in the Figures 1a to 1c The lower inlet area 4 has a substantially circular cross-section, a middle area with a rectangular cross-section defining a mixing chamber 5, and a discharge end 6, which also has a substantially circular cross-section. The inlet area 4 can be provided with a threaded section or similar fastening means for connecting the mixer to a cartridge, as indicated in the illustrated embodiment, and with an external profile.

[0037] The insert 3 is freely rotatable but axially fixed within the inlet area 4 and, for example, locked in place. The insert 3 is provided with two nozzles 7, which form the inlets of the mixer. The dispensing element 6 opposite the insert 3 is provided with an outlet 8. In the illustrated embodiment, a partition 9 is formed between the nozzles 7, which is provided with a coding element 10 projecting beyond the mixing sleeve 1. This coding element, not shown in detail, can engage in a corresponding opening of the cartridge to guide the mixer during the connection process. The nozzles 7 are connected to the mixing chamber 5 via partially radial or arcuate inwards channels 11.

[0038] The mixing element 2 is received in the rectangular section of the mixing sleeve 1 and has a projection into the Figures 1a to 1cAt its lower end, a plate 12 with a central inlet opening 12a is provided, through which the components to be mixed enter the mixing chamber 5 from the channels 11. In particular, the mixing element 2 can be inserted into the mixing sleeve 1 and is held axially by the plate 12 in such a way that displacement of the mixing element 2 towards the dispensing end 6 of the mixing sleeve 1, e.g., by the dispensing pressure of the components, is prevented. Two strips 13 of the mixing element 2 extend parallel to the longitudinal axis L and are connected to each other by a web 14 such that the mixing element 2 has an H-shape in a cross-section perpendicular to the longitudinal axis L. In the illustrated embodiment, the strips 13 extend over the entire width of the mixing chamber 5 in the region of the mixing sleeve with a rectangular cross-section.

[0039] The web 14 is provided with several passage openings, which in the illustrated embodiment are rectangular. First passage openings 15 extend over the entire width of the web 14 and thus border the two strips 13. Second passage openings 16, on the other hand, do not extend over the entire width of the web 14 and are thus positioned at a distance from the strips 13. This is also evident from Figure 2a and the enlarged detail A of the Figure 3 evident.

[0040] Several transverse walls 17, offset from one another in the direction of the longitudinal axis L, are formed on the web 14. In the illustrated embodiment, these transverse walls extend from one of the strips 13 to approximately the middle of the web 14. In a cross-sectional plane perpendicular to the longitudinal axis L, a first transverse wall 17 is present on one side of the web 14, while on the other side of the web 14, a transverse wall 17 offset from the first transverse wall is provided. In other words, for example, in the enlarged detail view in Figure 3 the front transverse wall 17 is connected to the right strip 13, while the transverse wall 17 provided on the rear of the bridge 14 is connected to the left strip 13.

[0041] Side walls 18 extend downwards from the transverse walls 17 parallel to the longitudinal axis L and perpendicular to the web 14 in the figures, i.e., towards the inlet area 4 of the mixer. In the axial direction, these side walls 18 do not extend to the next transverse wall 17, but are interrupted by further passage openings 19. The passage openings 15, 16 and the passage openings 19 are arranged offset from each other in the direction of the longitudinal axis L such that the passage openings 19 are provided in the areas where the web 14 is closed, i.e., where there are no passage openings 15, 16. Conversely, the passage openings 15, 16 are arranged in the areas where there are no passage openings 19 in the side walls 18.

[0042] The mixing sleeve 1, the strips 13, the web 14, the transverse walls 17, and the side walls 18 define chambers 20 and 21, through which the components to be mixed flow from the inlets to the outlet. The length of the chambers 20 and 21 in the direction of the longitudinal axis L is defined by the distance between two transverse walls 17 arranged one behind the other, parallel to the longitudinal axis L. The chambers differ primarily in the size of the openings 15 and 16 between the first chambers 20 and the second chambers 21, as well as in their arrangement within the mixer. Adjacent chambers are offset from each other by half a chamber length in the direction of the longitudinal axis L.

[0043] In this arrangement, each chamber is provided with two through-openings 15 and 16, respectively, and with two through-openings 19. Each chamber is connected via through-openings 15 and 16 to a chamber set back by half a chamber length along the longitudinal axis L and to a chamber set forward by half a chamber length on the opposite side of the web 14. Furthermore, each chamber is connected via through-openings 19 to a chamber set back by half a chamber length along the longitudinal axis L and to a chamber set forward by half a chamber length on the same side of the web 14. Thus, each chamber is connected via the four through-openings 15, 16, and 19 to four different other chambers. The deflection, splitting into partial flows, and merging of these partial flows of the components during the flow through the different chambers results in intensive mixing of the components.

[0044] In addition to these essentially identical chambers 20, 21, correspondingly incomplete chambers with only one or only two through-openings are present in the area of ​​the inlet and outlet ends of the mixer.

[0045] In the second embodiment of the Figures 4a and 4b The mixing element 2 is modified compared to the first embodiment in that storage chambers 22 are formed near the plate 12, which have only an inlet but no outlets. In these storage chambers 22, the initial quantity of a component that tends to flow forward can be collected and stored before entering chambers 20, 21, without this initial quantity participating in the further mixing process.

[0046] In the Figure 5A third embodiment of the mixing element 2 is shown. Compared to the embodiments described above, the mixing element 2 shown here comprises both a rectangular area 2a and a helical area 2b, which extends from the rectangular area 2a in the direction of component application. This has the advantage that the length of the mixing element 2 can be adapted to the specific application requirements. Since the rectangular area 2a provides good mixing but a high application pressure, while the helical area 2b provides a lower application pressure, the mixing effect, length, and application pressure can be adjusted to the specific application requirements by modifying the lengths of the rectangular area 2a and the helical area 2b.

[0047] The Figures 6a to 11cFigure 1 shows further embodiments of a mixing element 2 with a storage chamber 22. The components to be mixed can flow in through the inlet opening 12a provided centrally in the collar 15 from the insert 3 (not shown).

[0048] Figures 6a to 6c Show a mixing element 2 according to a fourth embodiment. From the longitudinal view of the Figure 6b The arrangement of the storage chamber 22 in the first part of the mixing element 2, viewed in the material discharge direction, can be seen. Furthermore, the section plane AA is shown, while the corresponding longitudinal section in the Figure 6c shown.

[0049] As the components flow in through the inlet opening 12a, they are divided at a side wall 18 and flow partly into a storage chamber 22 and partly into a flow chamber 23. From the flow chamber 23, the components flow through a passage opening 19 to the chambers 20, 21 of the mixing element 2.

[0050] In the fourth embodiment shown here, the cross-section of the passage opening 19 is smaller than the cross-section of the flow chamber 23. The smaller cross-section, in this case the cross-section of the passage opening 19, is decisive for the pressure drop during the discharge of the components.

[0051] This can result in relatively high discharge pressures, whereby the discharge pressure is also influenced by the specific design of the mixing element 2 and the specific viscosity of the components.

[0052] In the Figures 7a to 7c is a fifth mixing element 2 shown in a perspective view, a side view, and as a longitudinal section along the section plane BB. Compared to the one in the Figures 6a to 6c In the example shown, the mixing element 2 was shortened at its end located in the material discharge direction. This reduces the discharge pressure, making this embodiment suitable for components with higher viscosity.

[0053] The Figures 8a to 8c show a mixing element 2 in a sixth embodiment. Compared to the fourth embodiment according to the Figures 6a to 6c The draft angles on the open sides of the mixing element were increased. The draft angles have, in particular, an angular range of 0.1° to 2°, preferably 0.1° to 1°, and most preferably 0.5° ± 0.1°.

[0054] In the Figures 9a to 9c A seventh mixing element is shown, which has been widened in the area of ​​the reservoir chamber 22 and the flow chamber 23. This reduces the pressure during the discharge of the components, as the overall flow cross-section is increased in this area. Therefore, this embodiment is particularly advantageous for highly viscous components. In addition, the volume of the reservoir chamber 22 is increased, so that even larger feed flows can be compensated for.

[0055] An eighth mixing element 2 is in the Figures 10a to 10cAs shown, in this embodiment, the storage chamber 22 is reduced in size compared to the previous embodiments, thereby increasing the size of the through-opening 19. Here, the flow cross-section of the flow chamber 23 and the through-opening 19 are the same size. This, in turn, leads to a reduction in the discharge pressure compared to other embodiments.

[0056] The Figures 11a to 11c Figure 1 shows a ninth mixing element. Here, a transverse wall opening 24 has been added to a transverse wall 17 that closes off the flow chamber 23 in the material discharge direction. This allows some of the components to flow directly into the adjacent mixing chamber through the transverse wall opening 24 without having to pass through the through-opening 19. This reduces the discharge pressure of the components, as some of them do not have to change their flow direction to flow through the through-opening 19. Reference symbol list

[0057] 1 Mixing sleeve 2 Mixing element 2a Rectangular area 2b Helical area 3 Insert 4 Inlet area 5 Mixing chamber 6 Dispensing 7 Nozzle (Inlet) 8 Outlet 9 Partition 10 Coding element 11 Channel 12 Disc 12a Central inlet opening 13 Strip 14 Web 15 Through-opening 16 Through-opening 17 Transverse wall 18 Side wall 19 Through-opening 20 Chamber 21 Chamber 22 Storage chamber 23 Flow chamber 24 Transverse wall opening L Longitudinal axis

Claims

1. Mixer for mixing pasty components with a mixing sleeve (1) extending along a longitudinal axis (L) and having at least one inlet, preferably two inlets (7), and an outlet (8), and with at least one mixing element (2) received in the mixing sleeve (1), which together with the mixing sleeve (1) defines several chambers (20, 21) arranged one behind and / or beside each other along a flow path from the inlets (7) to the outlet (8), wherein the chambers (20, 21) are bounded by transverse walls (17) extending transversely to the longitudinal axis (L), and by four side walls (13, 14, 18) extending parallel to the longitudinal axis (L), and wherein adjacent chambers (20, 21) are in flow communication with each other via through-openings (15, 16, 19) provided in the side walls (14, 18), wherein the mixing element (2) has two strips (13) forming side walls which are connected by a web (14) forming further side walls and arranged perpendicular to the strips (13), and that a first group of chambers (20) has first passage openings (15) arranged in the web (14) which extend to a strip (13), and a second group of chambers (21) has second passage openings (16) characterized in that the mixing sleeve (1 ) has a first section with a rectangular cross-section in which the mixing element (2) is received, and a second section with a circular cross-section (6) in which the outlet (8) is provided, and in that the second passage openings (16) are positioned at a distance from at least one strip (13) in the web (14) spanning over a radial inner region of a mixing area.

2. Mixer according to claim 1, characterized in that the mixing sleeve (1) and the mixing element (2) form a third group of at least one chamber (22) which has closed side walls (13, 14, 18) as a storage chamber (22) and only one opening, which is formed as an inlet opening in a transverse wall (17).

3. Mixer according to claim 2, characterized in that at least one storage chamber (22) is provided at the inlet-side end of the mixing element (2).

4. Mixer according to one of the preceding claims, characterized in that the web (14) connects the strips (13) centrally.

5. Mixer according to one of the preceding claims, characterized in that the transverse walls (17) are connected to the web (14) and one of the strips (13), and that side walls (18) extend from the transverse walls (17) in the direction of the inlets (7) parallel to the strips (13).

6. Mixer according to one of the preceding claims, characterized in that chambers (20) of the first group and chambers (21) of the second group each have exactly four passage openings (15, 16, 19), of which two passage openings (15, 16) are formed in the web (14) and two further passage openings (19) run parallel to the web (14).

7. Mixer according to one of the preceding claims, characterized in that the mixing sleeve (1) and the mixing element (2) each form four chambers (20, 21, 22) arranged side by side in cross-section, which are at least partially offset from each other in the direction of the longitudinal axis (L).

8. Mixer according to one of the preceding claims, characterized in that the mixing sleeve (1) has an inlet section (4) in which an insert (3) having at least two nozzles (7) forming the inlets is sealed and is fixed, preferably in a manner rotatably with respect to the mixing sleeve (1).

9. Mixer according to claim 8, characterized in that the nozzles (7) of the insert (3) are flow-connected to the chambers (20, 21, 22) via channels (11) forming at least one compensation chamber and / or extending at least partially radially inwardly.

10. Mixer according to one of the preceding claims, characterized in that the chambers (20) of the first group and the chambers (21) of the second group are arranged in the middle and / or upper region of the mixing element (2) when viewed in the direction of application of the components.

11. Mixer according to one of claims 2 to 10, characterized in that the mixing element (2) has at least one flow chamber (23) adjacent to the storage chamber (22), wherein the at least one flow chamber (23) has at least one passage opening (19) running parallel to the web (14).

12. Mixer according to claim 11, characterized in that the cross-section of the flow chamber (23) perpendicular to the material discharge direction is 80% to 120% of the cross-section of the passage opening (19) of the flow chamber (23).

13. Mixer according to one of claims 11 or 12, characterized in that the flow chamber (23) is limited in the material discharge direction by a transverse wall (17), and that the transverse wall (26) has a transverse wall opening (27).

14. Mixer according to one of claims 2 to 13, characterized in that the cross-section of the mixing element (2) lying perpendicular to the longitudinal axis (L) in the section of the storage chamber (22) and / or flow chamber (23) is 105% to 150% of the cross-section of the mixing element (2) lying perpendicular to the longitudinal axis (L) in the subsequent section of the mixing element (2) viewed in the material discharge direction.