EP3608013A1

EP3608013A1 - Mixing segment, static mixer, dispensing assembly and method of mixing multi-component material

Info

Publication number: EP3608013A1
Application number: EP18188299.4A
Authority: EP
Inventors: Joachim Schoeck
Original assignee: Sulzer Mixpac AG
Current assignee: Medmix Switzerland AG
Priority date: 2018-08-09
Filing date: 2018-08-09
Publication date: 2020-02-12
Also published as: WO2020030456A1; DE212019000341U1

Abstract

A mixing segment (12) for a static mixer (2,3), the static mixer (2) comprising a plurality of mixing segments (12) for mixing a multi-component material (M, M'), the mixing segment (12) comprising: two or three inlets (13',13'',13''') arranged at a first side (15) of the mixing segment (12); and three outlets (14',14'',14''') arranged at a second side (16) of the mixing segment (12) oppositely disposed of the first side (15), with a longitudinal axis of the mixing segment (12) extending between the first and second sides (15,16); with one of the inlets (13'') being connected to two of the outlets (14',14''') and one or more of the other inlets (13',13'') being connected to the other one of the outlets (14''), with the respective inlets (13) being connected to the respective outlets (14) via respective passages (17) to deflect respective part flows of the multi-component material (M,M') from said inlets (13) to said outlets (14). Additionally a static mixer (2), a dispensing assembly (1,2) and to a method of mixing multi-component material (20) are disclosed.

Description

The present invention relates to a mixing segment of a static mixer. The invention further relates to a static mixer comprising a plurality of mixing segments, to a dispensing assembly comprising a static mixer and a multi-component cartridge filled with respective materials, as well as to a method of mixing multi-component material using a dispensing assembly.
Static mixers respectively mixing tips, as they are also known as, are used to mix multi-component material dispensed from a multi-component cartridge. Such static mixers are used in a plethora of fields of application ranging from industrial applications, such as the use of adhesives to bond structural components one to another, or as protective coatings for buildings or vehicles, to medical and dental applications, for example, to make dental molds.
The multi-component material is, for example, a two-component adhesive comprising a filler material and a hardener. In order to obtain the best possible mixing result, e.g. an adhesive having the desired bond strength, the multi-component material has to be thoroughly mixed.
For this purpose the static mixers comprise several mixing segments arranged one after the other that repeatedly divide and re-combine part flows of the multi-component material to thoroughly mix the multi-component material.
On mixing the multi-component material, the material remaining in the static mixer after the dispensing process is generally discarded as it remains in the static mixer. Depending on the field of application the multi-component material can be comparatively expensive and may only be used for one application at a time. This is particularly true, for example in the dental field, where only part of the multi-component material stored in the cartridge is used for one application/patient at a time with the remaining multi-component material being stored in the multi-component cartridge for future applications. Thus, the excessive use of large volumes of multi-component material remaining in a static mixer after a single use leads to unnecessary cost.
For this reason it is an object of the present invention to provide a static mixer in which the mixing efficiency is increased, with the mixing efficiency being a balance between low waste volume, low pressure loss and a good mixing quality. It is a further object of the invention to make available a static mixer that can be produced in an as facile manner as possible.
This object is satisfied by a mixing segment having the features of claim 1.
Such a mixing segment is configured for a static mixer and comprises a plurality of mixing segments for mixing a multi-component material, the mixing segment comprising:

two or three inlets arranged at a first side of the mixing segment; and
three outlets arranged at a second side of the mixing segment oppositely disposed of the first side, with a longitudinal axis of the mixing segment extending between the first and second sides;
with one of the inlets being connected to two of the outlets and one or more of the other inlets being connected to the other one of the three outlets, with the respective inlets being connected to the respective outlets via respective passages to deflect respective part flows of the multi-component material from said inlets to said outlets, wherein the respective passages have walls that are formed by curved surfaces.

In this way a so-called wave-shaped mixing segment is made available having at least two and optionally three inlets and three outlets.
Prior art wave-shaped mixing segments, such as helical mixers sold by Sulzer Mixpac for dental, Industrial and other applications, respectively comprise only two inlets and two outlets, with a division of the part flow of materials taking place between directly adjacent mixing segments, by arranging the inlets of one mixing segment at 90° relative to the outlets of the directly adjacent mixing segment. In the prior art wave-shaped mixing segments the respective part flows flowing through a passage of the mixing segment are redistributed by an initial compression and subsequent relaxation within the passage of the mixing segment. However, no division or combination of part flows of the material takes place within one mixing segment of the mixing element. The present invention makes it possible to divide and combine part flows of material both within a mixing segment and between directly adjacent mixing segments to further improve the mixing efficiency.
The mixing segments put forward in the present invention not only permit the redistribution of the individual flow paths within a mixing segment, but also make available a division and a combination of part flows of the multi-component material within the mixing segment in addition to the previously known division and combination between adjacent mixing segments. This is done in order to improve the through mixing of the multi-component material, to ensure a reduction in the pressure loss of the materials flowing through the static mixer and to minimize the amount of material left behind in a static mixer to increase the overall mixing efficiency that can be achieved by the static mixer in comparison to prior art mixers.
In the mixing segment in accordance with the present teaching a first inlet is connected to first and second outlets and a second inlet and optionally a third inlet is/are connected to a third outlet, with the respective inlets being connected to the respective outlets via respective passages to deflect respective part flows of the multi-component material from said first, second and optionally third inlets to said first, second and third outlets by means of division and combination of the part flows within the mixing segment.
The use of at least two and optionally three inlets and three outlets provides a plurality of part flow paths along which the multi-component material can flow, be divided and mixed. Increasing the number of flow paths within a mixing segment leads to an improvement of the mixing results achieved, since the respective part flows of the multi-component material are divided and re-combined more frequently into different part flow paths. This enables the mixing efficiency to be further improved by reducing the waste volume of material left behind in the static mixer.
Thus, the mixing segments are generally designed in order to achieve the best possible mixing results while using as small a volume of the respective material of the multi-component material as possible in order to limit the waste of multi-component material.
It has hitherto been found that the shape of the mixing segments contributes to the quality of the mixing result and also to the volume of multi-component material left behind in the static mixer. By forming the mixing segments such that they comprise curved walls respectively surfaces to guide the multi-component material between the inlets and the outlets, on the one hand, facilitates the mixing of the multi-component material and also reduces the space available within the mixing segment in which the multi-component material can be left behind after a dispensing process has taken place, as less so-called dead space results in curved mixing segments. In this way less of a volume of multi-component material is required to achieve a thorough mixing of the multi-component material while the absence of edges or angled surfaces in the flow paths reduces the pressure loss in the mixing segment. The combination of a reduction in pressure loss, the reduction in dead space and the improvement of the mixing results leads to an overall improvement of the mixing efficiency.
In this connection it should be noted that a curved surface is a surface that is not flat, i.e. planar, but rather is a surface that is rounded or curved in one or more dimensions, such as the outer surface of a ball, an apple, or an orange, i.e. a surface that does not comprise angled surfaces, such as edges, pockets, and protrusions etc.
In this connection it should be noted that the mixing of material present in each flow path is further facilitated by dividing e.g. the material made available at the largest flow path into two smaller flow paths and combining two smaller flow paths made available at the e.g. two outer inlets to then be available at the centrally arranged outlet. This division and combination within the mixing segment also contributes to the compression and relaxation of the material present within a flow path allowing this to be redistributed to further improve the mixing efficiency.
Curved surfaces, on the one hand, facilitate a guiding function of the walls of the passages and, on the other hand, are simple to manufacture in an injection molded process, in particular in comparison to so-called three way or four way mixers as well as T-mixers also sold by Sulzer Mixpac.
In one embodiment the mixing segment may be provided with two inlets and one of the inlets is connected to two of the outlets and the remaining one of the two inlets is connected to the other one of the three outlets, optionally wherein a main extent of the inlets is arranged such it is rotated by an angle of rotation of at least 45°, preferably of at least substantially 90° or of 90°, about the longitudinal axis with respect to a main extent of the outlet. In this way a mixing segment is made available in which the mixing efficiency is improved in comparison to prior art wave-mixing segments.
It is preferred if three inlets are provided and two of the three inlets are connected to only one of the three outlets and the third of the three inlets is connected to the other two of the three outlets, optionally wherein a main extent of the inlets is arranged such that it is in parallel to, or at least substantially in parallel to a main extent of the outlet(s) to which it is connected via the respective passage. The provision of three flow paths within a wave-shaped mixing segment further improves the mixing efficiency.
Preferably a curvature of the curved surfaces is selected such that a cross-section of the respective passage perpendicular to the longitudinal axis gradually changes in size between the respective inlets and the outlets. By forming the walls of the respective passages such that their curvature gradually changes a cross-section of the respective passage means that no abrupt changes in the direction of the flow path are brought about by elements that can be regarded as blocking elements which leads to a more uniform flow of the multi-component material within a mixing segment. This design hence results in a low pressure loss and thus in a higher mixing efficiency.
It should further be noted that a cross-section that gradually changes in size is a cross-section that increases or decreases in size by small degrees, for example linearly or in a curved manner, without jumps in the change in size as e.g. provided by steps, edges, recesses, protrusions or the like.
At least some and preferably all of the curved surfaces of the mixing segment may be curved in two dimensions. In this way the curved surfaces of the mixing segment may resemble a structure formed by a freeform surface. Such surfaces can be designed and manufactured in a comparatively simple manner and enable the production of mixing segments having uniform flow paths present therein.
A surface that is curved in two dimensions, is for example the outer surface of a rugby ball, and can generally be described as a surface that is curved both in a direction perpendicular to the longitudinal axis and in a second direction in parallel to the longitudinal axis.
In this connection it should be noted that a uniform flow path is a flow path in which no elements are present that negatively influence the speed of the respective material flowing in each of the respective passages, so that the speed of the material flowing in each of the respective passages is effectively the same and in which the different passages transport similar volume flows of material.
Mixing segments that are arranged directly adjacent to one another may be spaced apart from one another by means of spacers. The spacers are then present at at least one of the walls forming the respective inlets and one of the walls forming the respective outlets.
It should further be noted that the mixing segment may be formed in an injection molding process from a plastic material. Injection molded processes enable the bulk manufacture of a plethora of mixing segments in a comparatively short period of time in a simple and reproducible manner.
On forming the static mixers comprising a plurality of mixing segments in an injection mold, the shape of the static mixer and hence of the mixing segments is defined by the injection mold. In order to facilitate a fast and reliable removal of the injection molded parts, it is beneficial to avoid the use of too complex shapes to be molded.
The provision of such spacers facilitates the avoidance of too complex shapes in the region between the transition of one mixing segment to the next as the inlets and outlets of the directly adjacent mixing segments can be spaced apart from one another through the use of such spacers.
Additionally the spacers may also be used as flow stabilizing elements at the inlets and outlets of the mixing segments, as the region in which the spacers are arranged permit the flow of material to stabilize in that region as the flows of material do not experience any deflections in this region, as the passages do not comprise any deflection elements at the inlets and/or the outlets of the mixing segments.
The spacers may be formed of webs of material, i.e. strip of materials or projections, that extend at least partly over a complete length of a respective wall forming the respective inlet or outlet, i.e. a web of material may be a strip of material that extends beyond the height of the wall over a part of the length of the wall. In this connection the spacer(s) may integrally be formed with the mixing segment, optionally from the same material as the mixing segment. Forming such spacers that they only extend over a part of the length of a wall forming part of the inlet or outlet of the mixing segment further facilitates the release of the mixing segment from the injection mold thereby improving the manufacture of static mixers.
Walls forming part of the respective inlets and/or of the respective outlets of the mixing segments may be arranged in parallel to one another or at least substantially in parallel to one another at a respective inlet opening or at a respective outlet opening in the plane extending at least substantially perpendicular to or perpendicular to the longitudinal axis, with the respective inlets and outlets optionally being elongate inlets and outlets. The provision of such inlets and/or outlets leads to a particularly beneficial mixing efficiency particularly for mixing segments that are arranged within a housing having a cuboid like inner shape.
In this connection it should be noted that an elongate inlet respectively and elongate outlet is an inlet respectively an outlet that has a longer length than width.
Parts of the walls forming part of the respective inlets and/or the respective outlets may be arranged in parallel to one another or at least substantially in parallel to one another at a respective inlet opening or at a respective outlet opening in the plane extending at least substantially perpendicular to or perpendicular to the longitudinal axis. The remaining parts of the walls may then be arranged as converging or diverging from one another at the respective inlet opening or the respective outlet opening. Such shapes of inlet and/or outlet openings permit the tailoring of improved flow paths of the multi-component material within a series of mixing segments to further improve the mixing efficiency achievable with such a static mixer.
Walls forming part of the respective inlets and/or the respective outlets may alternatively be arranged as diverging from one another along a complete length of the respective wall at the respective inlet opening or the respective outlet opening in the plane extending at least substantially perpendicular to or perpendicular to the longitudinal axis. This design yields a particularly good mixing efficiency for static mixers arranged within a housing having a cylindrical inner shape.
The walls forming at least a part of the respective inlets and/or outlets may comprise edges at the respective inlets and/or outlets, with said edges optionally having a varying thickness along a length of the edge. In this way parts of the mixing segment can be improved in view of their manufacture in an injection mold.
A mixing segment may further comprise wedge shaped sections arranged in one or more of the respective passages. These wedge shaped sections, on the one hand, can improve the flow of multi-component within a mixing segment and, on the other hand, reduce the volume of dead space present within a mixing segment by being formed in regions of the mixing segment where such a dead space is likely to occur.
In this connection it should be noted that a wedge shaped section is a section that has a thick edge and a thin edge with the side walls tapering from the thick edge to the thin edge possibly with the side walls being formed by rounded or curved surfaces.
If three inlets are provided that are arranged next to one another in a mixing segment then an area of a centrally lying inlet may occupy between 40 to 60 % of a complete area of the combined inlet openings and in particular at least substantially 50% or 50% thereof. This means that a ratio of the area of the inlet openings can be selected in the range of 1.5:2:1.5 to 1:3:1, in particular of at least substantially 1:2:1 or of 1:2:1.
The three outlets of a mixing segment are arranged next to one another, with an area of a centrally lying outlet being able to occupy between 40 to 60 % of a complete area of the combined outlet openings and in particular at least substantially 50% or 50% thereof. This means that a ratio of the area of the outlet openings that are arranged next to one another is selected in the range of 1.5:2:1.5 to 1:3:1, in particular of at least substantially 1:2:1 or of 1:2:1.
According to a further aspect the present invention relates to a static mixer, the static mixer comprising a plurality of mixing segments of which at least some are configured as a mixing segment discussed in the foregoing.
The plurality of mixing segments may be arranged in series one after another along a longitudinal axis of the static mixer to form a mixing element. Moreover, the outlets of one mixing segment may be arranged next to the inlets of the next mixing segment of the series. In this connection the elongate inlets of at least some of the plurality of mixing segments may be arranged such that their extents are arranged substantially perpendicular to one another or in parallel to one another.
In this connection it should be noted that the individual mixing segments of the series can be separate from one another, but preferably at least some of the individual mixing segments of the series are connected to one another and are especially integrally formed as part of one mixing element or as one mixing element, for example in an injection molding process.
The advantages discussed in the foregoing in relation to the mixing segments likewise hold true for the static mixer in accordance with the invention.
According to a further aspect the present invention relates to a dispensing assembly, the dispensing assembly comprising a static mixer and a multi-component cartridge filled with respective materials.
The advantages discussed in the foregoing in relation to the mixing segments likewise hold true for the dispensing assembly in accordance with the invention.
The multi-component cartridge can thus be filled with materials selected from the group of members consisting of topical medications, medical fluids, wound care fluids, cosmetic and/or skin care preparations, dental fluids, veterinary fluids, adhesive fluids, disinfectant fluids, protective fluids, paints and combinations of the foregoing.
Such fluids and hence the dispensing assembly can therefore be expediently used in the treatment of target areas such as the nose (e.g. anti-histaminic creams etc.), ears, teeth (e.g. molds for implants or buccal applications (e.g. aphtas, gum treatment, mouth sores etc.), eyes (e.g. the precise deposition of drugs on eyelids (e.g. chalazion, infection, anti-inflammatory, antibiotics etc.), lips (e.g. herpes), mouth, skin (e.g. anti-fungal, dark spot, acne, warts, psoriasis, skin cancer treatment, tattoo removal drugs, wound healing, scar treatment, stain removal, anti-itch applications etc.), other dermatological applications (e.g. skin nails (for example anti-fungal applications, or strengthening formulas etc.) or cytological applications.
Alternatively the fluids and hence the dispensing assembly can also be used in an industrial sector both for the production of products as well as for the repair and maintenance of existing products, e.g. in the building industry, the automotive industry, the aerospace industry, in the energy sector, e.g. for windturbines, etc. The dispensing assembly can, for example, be used for the dispensing of construction material, sealants, bonding material, adhesives, paints, coatings and/or protective coatings.
According to yet a further aspect the present invention relates to a method of mixing multi-component material using a dispensing assembly, the method comprising the steps of:

dispensing multi-component material from the multi-component cartridge;
guiding the multi-component material to the static mixer;
making available at least two preferably three respective part flows of multi-component material at a first inlet and a second inlet and optionally at a third inlet of a mixing segment of the static mixer; and
guiding said one of said respective part flows from a first inlet to first and second outlets of said mixing segment and said respective part flow present at said second inlet and optionally at said third inlet to a common third outlet of said mixing segment to cause at least a partial mixing of the part flow in said mixing segment.

Further embodiments of the invention are described in the following description of the Figures. The invention will be explained in the following in detail by means of embodiments and with reference to the drawing in which is shown:

Fig. 1: a perspective view of a dispensing assembly;
Fig. 2: a perspective view of a mixing element of a static mixer;
Fig. 3: a perspective view of a further mixing element;
Fig. 4: a perspective view of a further mixing element;
Fig. 5: a perspective view of a further mixing element;
Fig. 6: a perspective view of a further mixing element;
Fig. 7: a perspective view of a further mixing element;
Figs. 8a to 8d: schematic views of the inlets of the mixing elements of Figs. 2, 4, 5 & 6; and
Figs. 9a and 9b: schematic views of the inlets and outlets of the mixing element of Fig. 7.

In the following the same reference numerals will be used for parts having the same or equivalent function. Any statements made having regard to the direction of a component are made relative to the position shown in the drawing and can naturally vary in the actual position of application.
Fig. 1 schematically shows a dispensing assembly 1 comprising a static mixer 2 and a multi-component cartridge 3. The multi-component cartridge 3 shown in Fig. 1 is a two-component cartridge 3' that is filled with respective two-component materials M, M', for example, a hardener and a binder material.
The static mixer 2 comprises two inlets 4, 4' at a first end 5 thereof. The two inlets 4, 4' connect to outlets 6, 6' of the two-component cartridge 3'. In the present example the inlets 4, 4' receive the outlets 6, 6' of the two-component cartridge 3'. It should be noted in this connection that other forms of interaction between the inlets 4, 4' and the outlets 6, 6' are possible.
A housing 7 of the schematically illustrated static mixer 2 further comprises alignment means 8, 8' that enable a correct alignment of the inlets 4, 4' of the static mixer 2 relative to the outlets 6, 6' of the two-component cartridge 3'. The alignment means 8, 8' can for example be configured as bayonet-like connection means (not shown) and hence also act as a kind of attachment means (not shown) to attach the static mixer 2 to the two-component cartridge 3'. Other kind of attachment means (also not shown) such as a locking ring can also be used and are well known to the person skilled in the art.
The housing 7 further has a dispensing outlet 9 at a second end 10 of the static mixer 2. The mixed multi-component material M, M' is dispensed via the dispensing outlet 9 following its passage through the static mixer 2. The dispensing outlet 9 is arranged at a longitudinal axis A of the static mixer 2. The longitudinal axis A extends from the inlets 4, 4' of the static mixer 2 to the outlet 9 of the static mixer 2.
Fig. 2 shows a perspective view of a mixing element 11 of the static mixer 2. The mixing element 11 is composed of six wave-shaped mixing segments 12. The six mixing segments 12 are arranged in series one after another along the longitudinal axis A of the static mixer 2. Each mixing segment 12 comprises an inlet region 13 and an outlet region 14. The outlet region 14 of one mixing segment 12 is arranged next to the inlet region 13 of the next mixing segment 12 of the series.
Each inlet region 13 comprises first, second and third inlets 13', 13", 13"' arranged at a first side 15 of the mixing segment 12 (see also Fig. 8 in this regard). Each outlet region 14 comprises first, second and third outlets 14', 14", 14'" arranged at a second side 16 of the mixing segment 12 oppositely disposed of the first side 15, with the longitudinal axis A of the static mixer 2 corresponding to the longitudinal axis A of the mixing segment 12 and extending between the first and second sides 15, 16.
The first and third inlets 13', 13'" of each mixing segment 12 are connected to the second outlet 14". The second inlet 13" is connected to the first and third outlets 14', 14'". The respective inlets 13', 13", 13'" are connected to the respective outlets 14', 14", 14'" via respective passages 17 to deflect respective part flows M" of the multi-component material M, M' from said inlets 13', 13", 13'" to said outlets 14', 14", 14'".
The respective passages 17 have walls 18 that are formed by curved surfaces 18'. The walls 18 are configured to separate the respective inlets 13', 13", 13'" from one another in the inlet region 13. Moreover, the walls are configured to separate the outlets 14', 14", 14"' from one another in the outlet region 14.
A main extent of the inlets 13', 13", 13'" is arranged such that it is in parallel to, or at least substantially in parallel to a main extent of the outlet(s) 14', 14", 14"' to which it is connected via the respective passage 17.
A curvature of the curved surfaces 18' is selected such that a cross-section of the respective passage 17 perpendicular to the longitudinal axis A gradually changes in size between the respective inlets 13, 13', 13", 13'" and the outlets 14, 14', 14", 14'" .
In this connection it should be noted that a cross-section of the respective passage 17 in a plane perpendicular to the longitudinal axis A is smallest in a middle region 32. The middle region 32 is generally the region arranged between the respective inlets 13, 13', 13", 13'" and outlets 14,14', 14", 14'", in particular the region arranged directly between the respective inlets 13, 13', 13", 13"' and outlets 14,14', 14", 14"'. It is in particular true that the cross-section gradually reduces in size between the inlet 13, 13', 13", 13'" and the middle region 32 and then gradually increases in size between the middle region 32 and the outlet 14, 14', 14", 14'" in order to achieve the desired compression and relaxation of the multi-component material M, M' in each flow path for a thorough throughmixing thereof.
In this connection it should further be noted that the cross-section of the respective passage 17 in the middle region 32 is approximately 30 to 80%, especially 40 to 60% of the cross-section of the respective passage at the inlet 13, 13', 13", 13'" and/or at the outlet 14, 14', 14", 14'".
It should further be noted that in one embodiment the shape of one of the respective passage 17 between the inlets 13, 13', 13", 13"' and the outlets 14, 14', 14", 14'" is elliptical or at least substantially elliptical in at least some cross-sections perpendicular to the longitudinal axis A.
In other embodiments the shape of one of the respective passage 17 between the inlets 13, 13', 13", 13'" and the outlets 14, 14', 14", 14'" is hyperbolic or at least substantially hyperbolic in at least some cross-sections perpendicular to the longitudinal axis A.
In other embodiments the shape of one of the respective passages 17 between the inlets 13, 13', 13", 13"' and the outlets 14, 14', 14", 14'" is V-shaped or at least substantially V-shaped in at least some cross-sections perpendicular to the longitudinal axis A.
An angle between the two shanks, i.e. the two walls 18, 18' forming the shanks, of the V-shaped or at least substantially V-shaped cross-section being selected in the range between 20° to 180° in a cross-section perpendicular to the longitudinal axis A.
It should be noted in this connection that if the mixing segment 12 comprises a passage 17 having a V-shaped structure in some cross-sections, such as the one e.g. shown in Fig. 2, then the V-shaped shape of the mixing segment 12 may be mirrored between the inlet 13 and the outlet 14 and the V-shaped shape of the mixing segment 12 changes over a length of the mixing segment 12 in parallel to the longitudinal axis A from e.g. an angle of 30° between the walls 18, 18' for the central passage 17 at the inlet to 330° between the walls 18, 18' for the central passage at the outlet 14, with the passage 17 at the inlet having the V-shaped outer walls 18, 18' not being the same passage at the outlet 14 having the V-shaped outer walls 18, 18'.
In yet further embodiments the shape of the respective passage 17 between the inlets 13, 13', 13", 13'" and the outlets 14, 14', 14", 14'" is a mixture of elliptical and/or hyperbolic and/or v-shaped or a mixture of at least substantially elliptical and/ at least substantially hyperbolic and/or at least substantially V-shaped in at least some cross-sections perpendicular to the longitudinal axis A.
The mixing segments 12 can be designed using e.g. freeform surface modeling such that the curved surfaces of each mixing segment 12 are curved in two dimensions.
In this connection it should be noted that each of the passages 17 is preferably designed such that it has no angular surfaces respectively geometrical elements that may cause dead spaces to arise, with dead spaces being regions in which multi-component material M, M' can collect and not further participate in the mixing procedure and with the dead spaces, for example, being formed by pockets, protrusions and edges etc.
Also indicated by means of a dashed line is one of the flow paths M" of the multi-component material M, M' as it flows through the mixing element 11. The flow path M" enters the first of six mixing segments 12 via the second inlet 13" and exits the mixing segment via the third outlet 14"'. The flow path M" then enters the second mixing segment 12 at the third inlet 13"' and exits the second mixing segment 12 via the second outlet 14". The flow path M" then enters the third mixing segment at the second inlet 13" and exits the third mixing segment 12 via the first outlet 14' to enter the third inlet 13'" of the fourth mixing segment 12 of the series. This progression of the flow path M" continues up until the flow path M" exits the sixth mixing segment 12 of the mixing element 11 via the third outlet 14"'.
Various flow paths M" exist in each mixing segment 12 and due to the arrangement of the mixing segments 12 such that the outlet region 14 of one mixing segment 12 are rotated by 90° with respect to the inlet region 13 of the directly adjacent mixing segment 12 a thorough through mixing of the various flow paths M" is brought about between the inlets 4, 4' of the static mixer and the dispensing outlet 9 of the static mixer 2. The curved surfaces of the mixing segments 12 ensure an as uniform as possible flow path M" is made available within each of the passages 17 of the mixing segments 12.
Ends 20 of the walls 18 of the curved surfaces 18' that form part of the respective inlets 13', 13", 13'" and of the respective outlets 14', 14", 14'" are arranged as diverging from one another at a respective inlet opening 21 and at a respective outlet opening 22 in the plane extending perpendicular to the longitudinal axis A.
In the plane extending perpendicular to the longitudinal axis A, the ends 20 of walls generally have a V-shape, more precisely a rounded V-shape and diverge from a common point 23.
Fig. 3 shows a further type of mixing element 11 with a mixing segment 12. Spacers 19 are arranged between directly adjacent mixing segments 12 of the mixing element 11. The spacers 19 are present at ends 20 of the walls 18 forming the parts of the respective first, second and third inlets 13', 13", 13"'.
It should be noted in this connection that the spacers 19 may also be formed alternatively or additionally at the walls 18 of the curved surfaces 18' forming parts of the respective first, second and third outlets 14', 14", 14"'.
The spacers 19 are formed of webs 19' of material that extend partly over a complete length of the end 20 of the wall 18 forming said part of the respective inlet 13', 13", 13'". In the present example the spacer 19 is integrally formed with the mixing segment 12 and from the same material as the mixing segment 12. It should be noted in this connection that the web 19' of material could be formed from a different material and could be formed by a different form of element.
The ends 20 of the walls 18 forming part of the respective inlets 13', 13", 13'" and/or the respective outlets 14', 14", 14'" are arranged in parallel to one another at the respective inlet opening 21 and at the respective outlet opening 22 in the plane extending perpendicular to the longitudinal axis A. The respective inlets 13', 13", 13'" and outlets 14', 14", 14'" of the mixing segments 12 thus have an elongate shape (see also the examples shown in Figs. 8c and 8d in this regard).
Fig. 4 shows a perspective view of a further mixing element 11. The mixing segments further comprise wedge shaped sections 24 arranged in two of the respective passages 17 of each mixing segment 12.
The wedge shaped sections 24 project into the passages 17 from ends 20 of the walls 18 separating the first, second and third inlets 13', 13", 13'", respectively the outlets 14', 14", 14'" from one another.
The wedge shaped sections 24, on the one hand, act as flow guiding or deflection members that are configured to deflect some of a part flow M" of the multi-component material M, M' within one of the passages 17 between the inlet region 13 and the outlet region 14.
On the other hand, the wedge shaped sections 24 are also configured to occupy a so-called dead space, in which multi-component material M, M' can collect without being readily mixed. Due to the lack of mixing, the multi-component material M, M' can often remain within a static mixer 2 at these positions without having been mixed. Through the provision of the wedge shaped sections 24 the amount of multi-component material M, M' remaining within a static mixer 2 after its use can hence be significantly reduced and the mixing results can further be improved.
As also shown the wedge shaped sections 24 project from the curved surfaces 18 as a triangular prism 25, with a vertex 26 of the respective prism 25 pointing either in or away from the direction of the longitudinal axis A.
Moreover, parts of the walls 18 forming part of the respective inlets 13', 13", 13"' and of the respective outlets 14', 14", 14'" are arranged in parallel to one another at the respective inlet opening 21 and at the respective outlet opening 22 in the plane extending perpendicular to the longitudinal axis A.
The remaining parts of the walls 18 are arranged as diverging from one another at the respective inlet opening 21 and at the respective outlet opening 22. The most spaced apart part of the walls 18 are aligned with two further vertices 27 of the prism 25. The respective bottom face 25' of the prism 25 forms part of the flow path in the region of the respective second inlet 13" or second outlet 14".
Fig. 5 shows a perspective view of a further mixing element 11. The ends 20 of the walls 18 forming the respective parts of the inlets 13', 13", 13'" and of the outlets 14', 14", 14'" are formed of straight sections of material. The straight sections are arranged such that the walls 20 present in the inlet region 13 and the walls 20 present in the outlet region 14 diverge from one another. This means that a spacing at one side 28 of the mixing segment 12 between the walls 18 is less than a spacing at the oppositely disposed side 29 of the mixing segment 12between the walls 18.
Fig. 6 shows a perspective view of a further mixing element 11. The mixing element 11 of Fig. 6 is configured to be placed into a cuboid shaped housing 7. To this end an envelope enclosing the mixing segment 11 along the longitudinal axis A of the mixing segments 12 is cuboid or at least substantially cuboid in shape. In the example shown the inlets 13', 13", 13"' and the outlets 14', 14", 14'" (see also Fig. 8d in this regard) have a generally rectangular shape at the inlet and outlet openings 21, 22.
Fig. 7 shows a perspective view of a further mixing element 11. The mixing segments 12 each comprise first and second inlets 13', 13" as well as first, second and third outlets 14', 14", 14'".
The first inlet 13' is connected to the first and third outlets 14', 14'" and the second inlet 13" is connected to the second outlet 14". A main extent of the inlets 13', 13" is arranged such it is rotated by an angle of rotation of 90° about the longitudinal axis A with respect to a main extent of the outlets 14', 14", 14'". The respective passages 17 are formed by the walls 18 that are formed by the curved surfaces 18'.
In this connection it should be noted that the mixing segments 12 shown in Figs. 2 to 7 can have a height in the direction of the longitudinal axis A selected in the range of 2 to 20 mm. In the example of Fig. 3 the height corresponds to 10 mm. In this connection it should be noted that it is preferable if the height of the mixing segment 12 corresponds to 80 to 120 % of a width or diameter of the mixing segment 12 along the longitudinal axis A.
It should further be noted that a thickness of each of the walls 18 can be selected in the range of 0.12 to 1.5 mm, especially of 0.16 to 1.05 mm. In the example shown e.g. in Fig 2 the walls 18 have a thickness that corresponds to 0.52 mm. In this connection it should be noted that it is preferable if the thickness of the walls 18 corresponds to 1 to 20% of the diameter of the mixing segment 12.
A diameter of the mixing segments 12 in a plane perpendicular to the longitudinal axis A of the mixing segments 12 of Figs. 2 to 5 and 7 can be selected in the range of 1.5 to 18 mm. In the example of Fig. 7 the diameter corresponds to 10 mm. In this connection it should be noted that the diameter of the mixing segment 12 is preferably selected to be between 80 and 120% of the length of the mixing segment 12.
In this connection it should be noted that if a mixing element 11 is configured for a cuboid shaped housing 7, such as the one shown in Fig. 6, that a side length of the mixing segments 12 in the plane perpendicular to the longitudinal axis can be selected in the range of 4 to 20 mm and in the example shown in Fig. 6 have a side length that corresponds to 10 mm. In this connection it should be noted that the side length of the mixing segments 12 is preferably selected in the range of 80 to 120 % of the length of the mixing segment 12 along the longitudinal axis A.
Preferably a wall thickness of each of the walls 21, 22 is selected to be 3 to 10%, preferably of 4 to 7% of the side length, height and/or the diameter of the respective mixing segment 12.
It should be noted that the ends 20 of the walls 18 forming at least a part of the respective inlets 13', 13", 13"' and the outlets 14', 14", 14"' comprise edges 21.
The edges 21 may have a varying thickness along a length of the edge 21. For example, the thickness may vary by up to 50% along the length of the edge 21. If an edge of varying thickness is provided then the reason for this is that the mixing segment 12 can, on the one hand, be carried out stiffer, and, on the other hand, be adapted to improve the flow and mixing path within a mixing segment 12.
The mixing elements 11 of Figs. 2 to 5 and 7 are configured to be placed into a cylindrical shaped housing 7 and to this end an envelope enclosing the mixing segments 12 along the longitudinal axis A of the mixing segments 12 is cylindrical or at least substantially cylindrical in shape.
In all of the embodiments shown the number of mixing segments 12 per mixing element may be selected in the range of 3 to 30, in particular 4 to 20, preferably 8 to 16, mixing segments 12 in dependence on the precise application.
Figs. 8a to 8d show views of the inlet regions 13 of the mixing elements of Figs. 2, 4, 5 & 6 respectively. The housing 7 surrounding the mixing segments at the inlet regions 13 is also indicated. In this connection it should be noted that the views of the outlet regions 14 are the same which is why they have been omitted. Needless to say any comments made with regard to the design and shape of the inlet regions 13 in Figs. 8a to 8d also hold true for the corresponding outlet region 14.
Fig. 8a shows a view of the inlet region 13 of the mixing segments 12 described in connection with Fig. 2. The inner wall of the housing 7 and the ends of the walls 18 of the curved surfaces 18' together form the inlet openings 21 of the first, second and third inlets 13', 13", 13"'. The first and third inlets 13', 13"' like the first and third outlets 14', 14" have a shape in the region of the inlet opening 21 respectively the outlet opening 22 that resembles that of a crescent. Whereas the shape of the second inlet 13" like that of the second outlet 14" resembles that of a curvilinear triangle.
Fig. 8b shows a view of the inlet region 13 of the mixing segment 12 described in connection with Fig. 4. The inlet region 13 has a circular cross-section in the plane perpendicular to the longitudinal axis A. Moreover, parts of the walls 18 forming part of the respective inlets 13', 13", 13"' (and of the respective outlets 14', 14", 14"') are arranged in parallel to one another at the respective inlet opening 21 (and at the respective outlet opening 22 respectively) in the plane extending perpendicular to the longitudinal axis A. The remaining parts of the walls 18 are arranged as diverging from one another at the respective inlet opening 21 (and at the respective outlet opening 22).
Fig. 8c shows a view of the inlet region 13 of the mixing segment 12 described in connection with Fig. 5. The ends 20 of the walls 18 are formed from straight sections of material that diverge from one side 28 of the mixing segment 12 to another side 29 arranged opposite from the one said side 28.
Fig. 8d shows a view of the inlet region 13 of the mixing segment 12 described in connection with Fig. 6. This is configured to be positioned within a housing 7 of cuboid shape. The inlet region 13 is divided into three inlet openings 21, with a sum of the area of the inlet openings 21 of the second and third inlets 13', 13'" corresponding to the same area as that of the second inlet 13". The three inlets 13', 13", 13'", like the three outlets 14', 14", 14'" have a rectangular shape at the respective inlet and outlet opening 21, 22.
In the embodiment of the mixing element 11 of Fig. 3 a drawing such as those shown in connection with Fig. 8a to 8d would show a circle of a cylindrical shaped housing 2 in the plane perpendicular to the longitudinal axis A and two walls 18 extending in parallel to one another, with the first and the third inlets 13', 13'" having a semicircular shape either side of the elongate second inlet 13".
From the examples shown in Figs. 8a to 9b it is apparent that the walls 18 that are formed by the curved surfaces 18' comprise edges 30 that are configured to be arranged directly adjacent to an inner surface 31 (see Figs. 8a to 9b) of the housing 7 of the static mixer 2. The edges 30 may generally be aligned relative to the inner surface 31 in such a way that none of the multi-component material M, M' can pass between the edges 30 and the inner surface 31.
Figs. 9a and 9b show views of the inlet region 13 and of the outlet region 14 of the mixing element of Fig. 7. The inlet region 13 is divided into two inlet openings 21 respectively having half the overall area of the combined inlet openings 21. The division is made by the wall 18 of the curved surface 18' as indicated in Fig. 9a. The outlet region 14 is divided into three outlet openings 22, with a sum of the area of the outlet openings of the second and third outlets 14', 14'" corresponding to the same area as that of the second outlet opening 14".
As indicated in the foregoing Figs. 8a to 9b if three inlets are provided and arranged next to one another, then an area of the inlet opening 21 of the second inlet 13", i.e. the centrally lying inlet, occupies between 40 to 60 % of a complete area of the combined inlet openings 21. It is preferred if the inlet opening 21 of the second inlet 13" occupies at least substantially 50% or 50% of the combined area of the inlet openings 21 of the first, second and third inlets 13', 13", 13'".
In this connection it should also be noted that if three outlets 14', 14", 14'" are provided and arranged next to one another, then an area of a centrally lying outlet opening 22 of the outlet 14" occupies between 40 to 60 % of a complete area of the combined outlet openings 22. It is preferred if the outlet opening 22 of the second inlet occupies at least substantially 50% or 50% of the combined area of the outlet openings 22 of the first, second and third inlets 13', 13", 13"'.
On use of the dispensing assembly 1, multi-component material M, M' is dispensed from the multi-component cartridge 3, 3'. The multi-component material M, M' is then guided to the static mixer 2. Depending on the precise design of the mixing element 11 of the static mixer 2 either two (see e.g. Fig. 7) or three (see e.g. Figs. 2 to 6) respective part flows M" of multi-component material M, M' are made available at the first inlet 13' and the second inlet 13" and, if provided, the third inlet 13'" of the first mixing segment 12 of the series of mixing segments 12 forming the mixing element 11 of the static mixer 2.
Once the multi-component material M, M' is made available at the inlet region 13 one of said respective part flows M" is guided from the second inlet 13" to the first and third outlets 14', 14'" of said mixing segment 12. In this way the part flow M" present at said second inlet 13" is divided into two part flows M" within the mixing segment. The respective part flow present at said first inlet 13' and optionally at said third inlet 13'" is guided to the second outlet 14" of said mixing segment 12, i.e. to a common outlet and thus these part flows are combined.
This division and combination of part flows M" takes place within one mixing segment. This causes at least a partial mixing of the part flows M" within said one mixing segment 12. This mixing of the part flows M" takes place in addition to the division and combination of part flows M" that takes place also in prior art mixers at the interface between directly adjacent mixing segments 12.

List of reference numerals:

1: dispensing assembly
2: static mixer
3, 3': multi-component cartridge, two-component cartridge
4,4': inlet
5: first end
6, 6': outlet
7: housing
8, 8': alignment means
9: dispensing outlet
10: second end
11: mixing element
12: mixing segment
13, 13', 13", 13"': inlet, first inlet, second inlet, third inlet
14, 14', 14", 14"': outlet, first outlet, second outlet, third outlet
15: first side
16: second side
17: passage
18, 18': wall, curved surface
19, 19': spacer, web of material
20, 20': end, edge
21: inlet opening
22: outlet opening
23: point
24: wedge shaped section
25, 25': prism, bottom face of 25
26: vertex
27: vertex
28: side
29: side
30: edge
31: inner surface
32: middle region
A: longitudinal axis
M, M', M": material, material, flow path

Claims

A mixing segment (12) for a static mixer (2), the static mixer (2) comprising a plurality of mixing segments (12) for mixing a multi-component material (M, M'), the mixing segment (12) comprising:
two or three inlets (13', 13", 13"') arranged at a first side (15) of the mixing segment (12); and

three outlets (14', 14", 14"') arranged at a second side (16) of the mixing segment (12) oppositely disposed of the first side, with a longitudinal axis (A) of the mixing segment (12) extending between the first and second sides;

with one of the inlets (13") being connected to two of the outlets (14', 14"') and one or more of the other inlets (13', 13'") being connected to the other one of the three outlets (14"), with the respective inlets (13', 13", 13'") being connected to the respective outlets (14', 14", 14'") via respective passages (17) to deflect respective part flows (M") of the multi-component material (M, M') from said inlets (13', 13", 13'") to said outlets (14', 14", 14'"), wherein the respective passages (17) have walls (18) that are formed by curved surfaces (18').
A mixing segment (12) in accordance with claim 1,
wherein three inlets (13', 13", 13'") are provided and two of the three inlets (13', 13'") are connected to only one of the three outlets (14") and the third of the three inlets (13") is connected to the other two of the three outlets (14', 14'"), optionally wherein a main extent of the inlets (13', 13", 13'") is arranged such that it is in parallel to, or at least substantially in parallel to a main extent of the outlet(s) (14', 14", 14"') to which it is connected via the respective passage (17).
A mixing segment (12) in accordance with claim 1,
wherein two inlets (13', 13") are provided and one of the inlets (13") is connected to two of the outlets (14', 14'") and the remaining one of the two inlets (13') is connected to the other one of the three outlets (14"), optionally wherein a main extent of the inlets (13', 13", 13'") is arranged such it is rotated by an angle of rotation of at least 45°, preferably of at least substantially 90° or of 90°, about the longitudinal axis (A) with respect to a main extent of the outlets (14', 14", 14'").
A mixing segment (12) in accordance with at least one of the preceding claims, wherein a curvature of the curved surfaces (18') is selected such that a cross-section of the respective passage (17) perpendicular to the longitudinal axis (A) gradually changes in size between the respective inlets (13', 13", 13'") and the outlets (14', 14", 14'").
A mixing segment (12) in accordance with at least one of the preceding claims, wherein at least some and preferably all of the curved surfaces (17') are curved in two dimensions, such as a freeform surface.
A mixing segment (12) in accordance with at least one of the preceding claims, wherein directly adjacent mixing segments (12) are spaced apart from one another by means of spacers (19) present at at least one of the walls (18) forming the respective inlets (13', 13", 13'") and one of the walls (18) forming the respective outlets (14', 14", 14'").
A mixing segment (12) in accordance with claim 6, wherein the spacers (19) are formed of webs (19') of material that extend at least partly over a complete length of a respective wall (18) forming the respective inlet (13', 13", 13"') or outlet (14', 14", 14'"), preferably with the spacer (19) being integrally formed with the mixing segment (12), optionally from the same material as the mixing segment (12).
A mixing segment (12) in accordance with at least one of the preceding claims, wherein walls (18) forming part of the respective inlets (13', 13", 13'") and/or the respective outlets (14', 14", 14'") are arranged in parallel to one another or at least substantially in parallel to one another at a respective inlet opening (21) or at a respective outlet opening (22) in the plane extending at least substantially perpendicular to or perpendicular to the longitudinal axis (A), with the respective inlets (13', 13", 13'") and outlets (14', 14", 14'") optionally being elongate inlets (13', 13", 13'") and outlets (14', 14", 14'").
A mixing segment (12) in accordance with at least one of the preceding claims 1 to 7, wherein parts of the walls (18) forming part of the respective inlets (13', 13", 13'") and/or the respective outlets (14', 14", 14'") are arranged in parallel to one another or at least substantially in parallel to one another at a respective inlet opening (21) or at a respective outlet opening (22) in the plane extending at least substantially perpendicular to or perpendicular to the longitudinal axis (A) and the remaining parts of the walls (18) are arranged as converging or diverging from one another at the respective inlet opening (21) or the respective outlet opening (22).
A mixing segment (12) in accordance with at least one of the preceding claims 1 to 7, wherein walls (18) forming part of the respective inlets (13', 13", 13'") and/or the respective outlets (14', 14", 14'") are arranged as diverging from one another at the respective inlet opening (21) or the respective outlet opening (22) in the plane extending at least substantially perpendicular to or perpendicular to the longitudinal axis (A).
A mixing segment (12) in accordance with at least one of the preceding claims 8 to 10, wherein the walls (18) forming at least a part of the respective inlets (13', 13", 13"') and/or outlets (14', 14", 14'") comprise edges (20') at the respective inlets (13', 13", 13'") and/or outlets (14', 14", 14'"), with said edges (21) having a varying thickness along a length of the edge.
A mixing segment (12) in accordance with at least one of the preceding claims, further comprising wedge shaped sections (24) arranged in one or more of the respective passages.
A mixing segment (12) in accordance with at least one of the preceding claims, wherein three inlets (13', 13", 13'") are provided that are arranged next to one another, with an area of a centrally lying inlet (13") occupying between 40 to 60 % of a complete area of the combined inlet openings (21) and in particular at least substantially 50% or 50% thereof; and/or wherein the three outlets (14', 14", 14'") are arranged next to one another, with an area of a centrally lying outlet (14") occupying between 40 to 60 % of a complete area of the combined outlet openings (22) and in particular at least substantially 50% or 50% thereof.
A static mixer (2) comprising a plurality of mixing segments (12) of which at least some are formed in accordance with at least one of the preceding claims.
A dispensing assembly (1) comprising a static mixer (2) in accordance with claim 14 and a multi-component cartridge (3, 3') filled with respective materials (M, M').
A method of mixing multi-component material using a dispensing assembly (1) in accordance with claim 14, the method comprising the steps of:
- dispensing multi-component material (M, M') from the multi-component cartridge (3, 3');

- guiding the multi-component material (M, M') to the static mixer (2);

- making available at least two preferably three respective part flows of multi-component material at a first inlet (13') and a second inlet (13") and optionally at a third inlet (13"') of a mixing segment (12) of the static mixer (2); and

- guiding said one of said respective part flows from a second inlet (13") to first and third outlets of said mixing segment (12) and said respective part flow present at said first inlet (13') and optionally at said third inlet (13'") to a common third outlet of said mixing segment (12) to cause at least a partial mixing of the part flow in said mixing segment (12).