EP1123730B1 - Static mixer - Google Patents

Abstract

A static mixer is disclosed comprising a mixer insert and an enclosing housing having a central axis. The insert includes at least three interleaved grids and each of the grids includes a plurality of layers that are superposed parallel one to the others. Each of the layers includes a plurality of bars that are mutually parallel one to the others. There is an angle of 30 to 60 degrees between each of the bars and the axis.

Description

The invention relates to a static mixer consisting of at least one Mixer insert, possibly a support and possibly a hold-down device, with an enclosing housing, the mixer insert from a variety of nested grids, parallel to each other, one on top of the other lying layers arranged webs is composed and wherein the Grid against each other by an angle α around the main direction of flow through the Mixers are arranged twisted.

There are many uses for mixing especially high-viscosity liquids static mixer used. A pump presses the liquid through static mixer built-in pipe, the main flow axis The following liquid is divided into partial flows, which, depending on the type of internals be swirled and mixed.

The following two devices may be mentioned as examples of static mixers:

With the so-called Kenics mixers (see "Mixing during manufacture and processing von Kunststoffe ", publisher VDI Ges. Kunststofftechnik, VDI publishing house 1986, pp. 238-241), the liquid flow of the mixed material is through a into one Pipe installed divider divided into partial flows. This divider is around that Tube axis twisted. A vortex-shaped flow arises in each of the partial flows, which leads to the redistribution of the liquid in the cross section of the tube. Usually several such mixing elements are arranged one behind the other to form the liquid to share again and again and to achieve a sufficient mixer result. A satisfactory mixture is typically only after 10 to 12 mixing elements reached.

The further known so-called SMX mixers (cf. patent specification US-A-40 62 524) consist of two or more mutually perpendicular grids of parallel Metal strips that are welded together at their crossing points and in are made at an angle to the main flow direction of the mixture, in order to to divide and mix the liquid into partial flows. The manufacturing cost for this mixer is very high because of the many welded joints to be made. A single mixing element is unsuitable as a mixer because it only mixes takes place along a preferred direction transverse to the main flow direction. Therefore several mixing elements, which are rotated by 90 ° to each other, must be used one after the other to be ordered. Good mixing typically requires 5 to 6 mixer elements arranged one behind the other.

This can be explained as follows: An SMX mixer only points two against each other grid of parallel webs rotated by 180 °. These grids consist of layers more equidistant Stege. Adjacent layers are aligned. Any location represents a plane of symmetry that is not crossed when mixing.

The object of the invention is to provide a static mixer which the Mixing effect of the known mixers, especially the SMX mixer, exceeds and can be produced with a minimal manufacturing outlay.

The object is achieved according to the invention by a static mixer at least from a housing with possibly a support and possibly a hold-down and with a mixer insert consisting of at least three against each other parallel webs twisted around the direction of flow, leading to Flow direction are set.

The invention relates to a static mixer consisting of at least one Mixer insert, possibly a support and possibly a hold-down device, with an enclosing housing, the mixer insert consisting of at least three nested grids of parallel to each other, one on top of the other lying layers arranged webs is composed and wherein the Grid against each other by an angle α around the main direction of flow through the Mixers are arranged twisted.

With this construction, the bars of one grating can pass through the bars of the other Grids are held in position without being connected have to. Therefore there is no additional effort for welding the Bridges required in this construction.

Because of the arrangement according to the invention, there is no mirror symmetry plane, so that the mixing effect is biaxial.

A preferred embodiment of the static mixer is characterized in that that the webs to the main flow direction through the mixer by an angle β preferably from 30 to 60 °.

In a preferred variant of the static mixer, the webs are a grid through the bars of the other grilles, the housing and the terminal bars fixed in position by the support and / or the hold-down device.

The number of grids in the mixer insert is preferably static Mixer three or four.

The static mixer is particularly preferably rotationally symmetrical the number of grids built up.

A preferred embodiment of the static mixer is characterized in that that three grids with parallel webs are built from parallel layers of webs are, with adjacent layers each sitting on a gap.

Another preferred embodiment of the static mixer is characterized in that that four grids with parallel webs are built from parallel layers of webs are, with adjacent layers aligned with each other.

In a further preferred form of the static mixer, adjacent grating planes are of a grid is offset from each other and the number of grids is four.

If the static mixer is also to be used as a heat exchanger, you can the webs are designed as hollow webs which open into the housing wall, wherein the housing wall is a casing with feeds divided into several chambers and has derivatives for a heat transfer medium.

Another object of the invention is the use of the invention static mixer for mixing highly viscous mix, in particular Polymer melts or polymer solutions with additives, other polymers, Dyes, pigments or stabilizers.

The invention is explained below with reference to the figures by the examples which however, do not constitute a limitation of the invention, explained further.

Figur 1a

einen erfindungsgemäßen Mischer in einer perspektivischen Ansicht, dabei ist das Gehäuse geschnitten dargestellt.

Figur 1b

den Mischer aus Figur 1a in der Draufsicht

Figur 2

das Gehäuse des Mischers aus Figur 1 im Längsschnitt

Figur 3

die Anordnung der Stege innerhalb des Mischers aus Figur 1a in perspektivischer Ansicht

Figur 4

die Anordnung der Stege innerhalb des Mischers aus Figur 1a bei Blickrichtung entlang der Stege

Figur 5

eine Anordnung von Stegen für einen Mischer mit einem quadratischen Querschnitt und mit vierzähliger Rotationssymmetrie

Figur 6

die Seitenansicht eines erfindungsgemäßen Mischers in der Funktion als Wärmetauscher

Figur 7

den Querschnitt durch den Mischer/Wärmetauscher aus Fig. 6

Figur 8

den Längsschnitt durch den Mischer/Wärmetauscher aus Fig. 6

Figur 9

den Mischereinsatz im Mischer/Wärmetauscher aus Fig. 6

Figur 10

einen alternativen Mischereinsatz mit vier Gittern

Show it:

Figure 1a

a mixer according to the invention in a perspective view, the housing is shown in section.

Figure 1b

the mixer of Figure 1a in plan view

Figure 2

the housing of the mixer of Figure 1 in longitudinal section

Figure 3

the arrangement of the webs within the mixer of Figure 1a in a perspective view

Figure 4

the arrangement of the webs within the mixer of Figure 1a when looking along the webs

Figure 5

an arrangement of webs for a mixer with a square cross-section and with four-fold rotational symmetry

Figure 6

the side view of a mixer according to the invention in the function of a heat exchanger

Figure 7

the cross section through the mixer / heat exchanger from FIG. 6

Figure 8

the longitudinal section through the mixer / heat exchanger from FIG. 6

Figure 9

the mixer insert in the mixer / heat exchanger from FIG. 6

Figure 10

an alternative mixer insert with four grids

Examples: example 1

A static mixer according to the invention is shown in a perspective view in FIG View shown; the housing 1 is shown cut away.

In the top view of the mixer according to FIG. 1b it can be seen that the mixer is constructed three times rotationally symmetrical around the flow mixture.

In the longitudinal section of the housing 1 in Figure 2, the arrangement of the support 3 and of the hold-down 4 can be seen.

In the representation of the mere mixer insert according to Figure 3 it can be seen that the three nested meshes with parallel webs of parallel layers 5a, 5b of webs 2a, 2b, 2c; 6a, 6b, 6c; 7a, 7b, 7c are constructed, with neighboring ones Layers 5a (with the webs 2a, 2b, 2c) and 5b (with the webs 12a, 12b, 12c) to each other to sit on gap.

Figure 4 shows a view along the bars of a grid. It can be seen that the Bars 2a, 2b, 2c through the bars 6a, 6b, 6c and 7a, 7b, 7c of the other grids in their Location are fixed. Bridges are only added in the top and bottom layers fixed by the support 3 or the hold-down device 4 (not shown in FIG. 4).

Example 2

Figure 5 shows an arrangement of webs for a mixer insert with a square cross-section and with fourfold rotational symmetry of the webs to each other. This mixer insert requires a housing 1 with a square cross section.

Example 3

Figures 6, 7 and 8 show a mixer / heat exchanger consisting of a Outer housing 10 and an inner housing 1, with nozzle 13 for the product supply and nozzle 14 for product removal, and a feed line 11 and a drain 12 for a temperature control medium. Walls between outer housing 10 and inner housing 1 divide the space into two chambers 15 and 16 for the supply and discharge of the heat transfer medium. FIG. 9 shows the arrangement of the tubes Ridges 17 inside the mixer / heat exchanger. It is marked by four grids with parallel webs, which are at 90 ° to each other Flow direction are arranged rotated.

A particularly narrow pipe arrangement is achieved in that adjacent grid levels of a grid are arranged offset from one another.

Example 4

Figure 10 shows an alternative arrangement of the hollow webs of the mixer insert for a mixer / heat exchanger as shown in Example 4. Adjacent grid levels aligned with each other, the number of grids is four.

Such a mixer / heat exchanger is particularly suitable for 2-phase flows. Since the distance of the pipes across the flow direction is large compared to the distance in the main flow direction, there are large flow channels for the product. The arrangement of the tubes results in one in these flow channels Swirl flow with separation into a gas flow inside the channel and a liquid flow on the outside of the channel. This can cause pressure loss when Flow through such a mixer / heat exchanger can be kept small.

Claims (13)

1. A static mixer consisting at least of a mixer insert (2), where appropriate a support (3) and where appropriate a hold-down device (4), with a surrounding casing (1), the mixer insert (2) being composed of at least three nested trellises of slats (2a, 2b, 2c; 12a, 12b, 12c) which are parallel to one another and arranged in superimposed layers (5a, 5b), and the trellises being arranged in relation to one another twisted by an angle α about the direction of main flow through the mixer.
2. Static mixer according to Claim 1, wherein the slats (2a, 2b, 2c; 12a, 12b, 12c) are positioned at an angle β relative to the direction of main flow through the mixer.
3. Static mixer according to Claim 2, wherein the angle β amounts to from 30° to 60°.
4. Static mixer according to one of Claims 1 to 3, wherein the slats (2a, 2b, 2c; 12a, 12b, 12c) of one trellis are fixed in their positions by the slats (6a, 6b, 6c, 7a, 7b, 7c) of the other trellises, the casing (1) and also in the case of the terminal slats (2a, 2b, 2c) by the support (3) and/or by the hold-down device (4).
5. Static mixer according to one of Claims 1 to 4, wherein the number of trellises amounts to three.
6. Static mixer according to one of Claims 1 to 4, wherein the number of trellises amounts to four.
7. Static mixer according to one of Claims 1 to 6, wherein the mixer is constructed to be rotationally symmetrical, corresponding to the number of trellises.
8. Static mixer according to Claim 5, wherein the three trellises with parallel slats (2a, 2b, 2c; 6a, 6b, 6c; 7a, 7b, 7c) are constructed from parallel layers of slats (2a, 2b, 2c; 12a, 12b, 12c), respectively adjacent layers being seated relative to one another on an interstice.
9. Static mixer according to Claim 6, wherein the four trellises with parallel slats are constructed from parallel layers of slats, adjacent layers being aligned with one another.
10. Static mixer according to one of Claims 1 to 9, wherein the slats (2a, 2b, 2c; 12a, 12b, 12c) take the form of hollow slats and open out in the wall of the casing, the wall of the casing exhibiting a jacket divided into several chambers, with feeds and drains for a heat-transfer medium.
11. Static mixer according to one of Claims 1 to 10, wherein adjacent trellis planes of a trellis are offset in relation to one another and the number of trellises amounts to four.
12. Static mixer according to one of Claims 1 to 10, wherein adjacent trellis planes of a trellis are aligned with one another and the number of trellises amounts to four.
13. Use of the static mixer according to one of Claims 1 to 12 for mixing high-viscosity material to be mixed, in particular polymer melts or polymer solutions with additives, other polymers, dyestuffs, pigments or stabilising agents.

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