EP1600205A1 - Mixing apparatus and method for adding an additive to a pumpable mixture - Google Patents

Abstract

Apparatus for mixing an additive into a pumpable viscoplastic mixture passing through a conduit (8) comprises injectors in the conduit and a downstream mixing chamber (9) in which the additive is dynamically mixed with the viscoplastic mixture. An independent claim is also included for adding an additive to a pumpable viscoplastic mixture passing through a conduit by adding the additive through injectors and mixing the additive with the pumpable mixture in a downstream dynamic mixing chamber.

Description

Technical area

The invention is based on a mixing device according to the preamble of the first claim.
The invention is also based on a method for adding an additive to a pumpable mixture according to the preamble of the independent method claim.

State of the art

The admixing of small quantities of a substance, e.g. of an additive in a mixture with plastic-viscous behavior occurs in many applications on. However, good mixing is often difficult to achieve. For example, for mixing an additive, e.g. an activator with fine mortar used a static mixer. If you use such static mixers also on standard concrete, the static mixer clogs due to the coarse gravel quickly and the mixer can even be destroyed become.

The addition of the activator in the ready-mix concrete and the mixing becomes Therefore, many already made in the vehicle drum. Of the Activator liquefies the concrete and activates the setting mechanism. The disadvantage is that after the activator the concrete in the vehicle drum was not allowed to pass much time until the activated Concrete is processed in the building, otherwise it already hardens before.

Presentation of the invention

The invention is based on the object at a mixing device and a method of the type mentioned a mixing device To specify which makes it possible to quickly add additives in a plastic-viscous To introduce mixture and to achieve a good mixing.

According to the invention, this is achieved by the features of the first claim reached.

The core of the invention is therefore that in a line at least one Injection means for adding additive is arranged in the mixture, that downstream of a mixing space is arranged, in which the additive is dynamically mixed with the plastic-viscous mixture.

The advantages of the invention are, inter alia, that a good Mixing of plastic-viscous mixture and additive is achieved. This at a relatively short mixing distance and that the mixing shortly before the processing site can be made. The one shown here Method and apparatus are particularly suitable for continuous Adding and mixing very small amounts of chemical additives in one Pumpable mixture with plastic-viscous behavior, especially in a Granules suspension mixture such as concrete.

Further advantageous embodiments of the invention will become apparent from the Dependent claims.

Short description of the drawing

In the following, with reference to the drawings, embodiments of Invention explained in more detail. Same elements are in the different figures provided with the same reference numerals. The flow direction of the media as well as the direction of rotation of the elements of the device is with arrows specified.

Fig. 1

schematisch die Verarbeitung von Beton in einem Bauwerk;

Fig. 2

schematisch die erfindungsgemässe Mischeinrichtung;

Fig. 3a

schematisch Mittel zur Grobverteilung für den Zusatzmittel;

Fig. 3b

Detaildarstellung des Eindüsungsmittels für das Zusatzmittel aus Fig. 3a;

Fig. 4a

schematisch weitere Mittel zur Grobverteilung für das Zusatzmittel;

Fig. 4b

Detaildarstellung des Eindüsungsmittels für das Zusatzmittel aus Fig. 4a;

Fig. 4c

Detaildarstellung des Eindüsungsmittels für das Zusatzmittel aus Fig. 4a;

Fig. 4d

schematisch die Zusatzmittelverteilung im Gemisch;

Fig. 5

schematisch eine Ausführungsform des Mischraums;

Fig. 6

ein Mischelement mit Eindüsungsmitteln für das Zusatzmittel im Teilquerschnitt;

Fig. 7

schematisch mögliche Mischelemente;

Fig. 8

schematisch eine weitere Ausführungsform des Mischraums;

Fig. 9

schematisch eine weitere Ausführungsform des Mischraums mit mehreren Mischwellen;

Fig. 10

Vermischung mit zwei Wellen entsprechend Fig. 9;

Fig. 11

schematisch eine weitere Ausführungsform des Mischraums.

Show it:

Fig. 1

schematically the processing of concrete in a building;

Fig. 2

schematically the inventive mixing device;

Fig. 3a

schematically distribution means for the additive;

Fig. 3b

Detailed representation of the injection means for the additive of Fig. 3a;

Fig. 4a

schematically further coarse distribution means for the additive;

Fig. 4b

Detailed representation of the injection means for the additive of Fig. 4a;

Fig. 4c

Detailed representation of the injection means for the additive of Fig. 4a;

Fig. 4d

schematically the additive distribution in the mixture;

Fig. 5

schematically an embodiment of the mixing chamber;

Fig. 6

a mixing element with injection means for the additive in the partial cross section;

Fig. 7

schematically possible mixing elements;

Fig. 8

schematically a further embodiment of the mixing chamber;

Fig. 9

schematically a further embodiment of the mixing chamber with a plurality of mixing shafts;

Fig. 10

Mixing with two shafts according to Fig. 9;

Fig. 11

schematically another embodiment of the mixing chamber.

It is only essential for the immediate understanding of the invention Elements shown.

Way to carry out the invention

FIG. 1 schematically shows the processing of a plastic-viscous mixture, FIG. shown here by concrete 10 in a building. By means of a Transport vehicle 1 concrete is delivered to the construction site. Not shown that the concrete is usually mounted in a mounted on the transport vehicle, is transported rotating drum. This concrete was in the concrete plant so treated with additives that the hydration or Tying mechanism is delayed by several hours. This concrete corresponds generally to a pumpable granule suspension mixture with plastic-viscous behavior. The concrete 10 is placed in a container 2 stored or directly from the vehicle by means of a pump 3 and a line 4 pumped under pressure to the site. Such a line can while transporting the concrete over several 100 meters or even some Kilometers are used. Prior to the processing of the concrete 10 must this for processing by adding additives 5 (also additive called), such as activators, e.g. a setting accelerator, reactivated become. The addition of the additive takes place in a mixing device 6. About another line 7 may be supplied with further substances, e.g. Water, Concrete from another source, etc .. The mixed with the admixture 5 Concrete 10 'is then at the construction site at the processing 20 accordingly processed. The processing of the concrete can be done by any method take place, e.g. by spraying, casting, etc .. The distance from The mixing device to the processing is arbitrary, but will advantageously chosen as short as possible, so that as little waste accumulates, or activated concrete remains in the line and this possibly makes us unusable. With the present mixing device it is also possible the line from the mixer to the processing with not activated concrete 10 by no activator in the mixing device more is added. This will prevent the line from clogging. By the mixing device shown here it is allowed, small To add additive amounts to the plastic-viscous mixture and to mix, in particular in a ratio of 1: 100 to 1: 1000.

In Fig. 2, the mixing device 6 is shown in more detail. This mixing device 6 comprises a feed line 8 and a mixing chamber 9. The diameter of the mixing chamber 9 is advantageously greater than that of the feed line 8 in order to reduce the flow rate through the mixing chamber. The mixing space is preferably cylindrically shaped because of the high pressures and may have a small volume of less than 100 liters. The present mixing method is preferably carried out as an inline mixing method which is under pressure. In the supply line 8, which is preferably angled, means 11 for coarse distribution of the additive 5 in the concrete 10 are arranged. In the mixing chamber an unillustrated mixing element is arranged, which can be driven by a drive 13 via a shaft 12. Through the shaft 12 and arranged in the mixing chamber 9 mixing element additional additive 5 can be introduced into the concrete. Furthermore, additive 5 can be injected in the initial region of the mixing chamber 9, wherein the injection means to be used can be formed analogously to the injection means 14, 14a. The additive can thus be introduced at the same time at several points over the line cross-section and distributed by the downstream mixing chamber both axially and radially homogeneous, respectively, are mixed. This results in a homogeneous distribution of the additive in the concrete 10 'at the end of the mixing space, so that a uniform activation of the concrete takes place.
The bending of the feed line has several advantages. Thus, the angling allows the drive and the shaft for the mixing chamber to be arranged on one axis without obstructing the mixture flow. In addition, injection means 14a can be arranged in the angling over which additive can be introduced into the edge region of the pumped concrete in spite of the smear layer in the edge region.
The addition of the additive 5 is advantageously carried out at the same or a greater flow rate than that of the concrete. The relative velocity of the additive is then greater than zero compared to the concrete. As a result, a safe injection of the additive can be ensured, and that the nozzles to be used for injection do not clog.

In Fig. 3a, the means 11 for coarse distribution of the additive are more accurate shown. Via arranged in the supply line 8 injection means 14th the additive 5 is introduced by means of several nozzles 15 in the concrete. The injection means 14 are shown in FIG. 3 as a tube with holes as However, nozzles 15 shown, but can also be formed differently. The Injected admixture 5 forms threads in the pumped through the line Concrete. These threads are shown in cross-section II) of Fig. 3. Since the Concrete pumpable granulate suspension mixture with plastic-viscous Behavior corresponds, the Reynolds number Re of the concrete lies in the Line approximately in a range of Re = 1 to 1000, so the flow is laminar, creeping. This means that the additive is not caused by turbulence is mixed, but "as a thread" long remains intact. The over the Set line length and cross-section arranged Eindüsungsmittel 14, 14a several "threads" distributed over the cross section in the laminar concrete stream. As with mixtures such as concrete at the edge of the cross section of the line a Smear layer is formed and because of the rheological properties of the Concrete, the additive is advantageously over the entire Cross-section and not marginally added so that the additive in the Concrete can be introduced.

According to Fig. 3b, the nozzles 15 in the injection means 14 are preferably so arranged that the injection of the additive in the flow direction of the Concrete 10 is done. As a result, the nozzles 15 are not penetrated by the concrete clogged and the added additive forms a thread-like in concrete Structure and does not dwell in the smear layer, as with the addition over Wall openings in the supply line 8 would happen.

In Fig. 4a further means 11 for coarse distribution of the additive are shown. The supply line 8 has an extension, in which an injection means 14 'is arranged. The injection means 14 'serves as a flow divider, which divides the concrete stream 10 into two parts. The additive 5 is introduced at the downstream end of the injection means 14 'by means of a plurality of nozzles 15 in the concrete, see Fig. 4b, 4c. The injection means 14 'has a substantially elliptical cross section with sharp arrival and trailing edges. This injection means 14 'is built relatively solid, for example, to be able to withstand stones in the concrete and thus to prevent damage to the Eindüsungsmittels. The cross-section of the supply line 8 is extended according to the dimensions of the injection means, so that the concrete flow flows evenly and the flow of the concrete is influenced as little as possible. If desired, however, the cross-section can also be adapted so that the flow is accelerated or slowed down in the region of the injection of the admixture.
In addition, in the region of the nozzles 15, injection means 14a can also be arranged in the edge region of the supply line in order to inject additives in the edge region.

According to Fig. 4b and 4c, the injection means 14 'different in Feeding means 8 are aligned. Especially if several Injector means 14 'are arranged in series in the feed means 8 advantageous to align them differently in the feeding means, as this is shown schematically in Figs. 4b and 4c.

In Fig. 4d, the additive distribution in the concrete is downstream of two Injection means 14 'shown in FIG. 4b and 4c. It turns out a good distribution of the additive in the concrete, which by additional Injection agent can be improved.

The task of additive via the injection means 14, 14 ', 14a takes place advantageously such that the additive volume flow is proportional everywhere is adapted to the flow rate of the granular suspension mixture and Thus, over the entire cross section, the same amount of additive is distributed. This means that on the edge quantitatively less additives is admitted as in the middle region of the line. This because the granule suspension mixture on the edge of a much smaller flow velocity as in the middle. The addition of the same amount of additive just on the edge would lead to an accumulation of the additive on the edge lead to the middle region of the line.

In Fig. 5, the mixing chamber 9 is shown in detail. In the mixing chamber 12 several stages of mixing elements 16 are arranged in the flow direction on the shaft, but it can also be used only one mixing element. The shaft 12 is set in rotation via the drive, not shown here, so that the already added thread-shaped additive is cross-mixed in the concrete. The shape of the mixing elements is arbitrary per se, with some possible embodiments being described in the following FIG. 7. Additive 5 can also be supplied directly through the mixing elements 16 in the concrete, the nozzles are formed analogous to the Eindüsungsmitteln. The supply of the additive takes place via the shaft 12. At the edge of the mixing chamber 9 static mixing elements 17 may additionally be arranged, which support the mixing process of the mixing elements 16. The number, shape and position of the static mixing elements 17 mounted on the wall or inside are such that they do not cause clogging. In addition, the static mixing elements 17 prevent marginalities.
The shaft 12, which is mounted on a bearing 12a, need not necessarily lie on the central axis of the line 8, but can also be arranged in a particular case for better mixing next to the central axis, as symbolized in the figure by the double arrow.

In Fig. 6, a mixing element 16 is shown in detail. The shaft 12 and the mixing element 16 have holes through which the additive 5 is passed to nozzles 15 through which exits the additive. Again, the nozzles 15 are preferably arranged in the mixing element 16 so that the injection of the additive takes place in the flow direction of the concrete 10. As a result, the nozzles 15 are not blocked by the concrete. Of course, the nozzles can be arranged over the entire radial extent of the mixing element 16 or only over certain partial areas.
The nozzles do not have to be arranged symmetrically, so that the mixing can be improved depending on the design by a certain asymmetry.

In Fig. 7 are several different possible embodiments of Mixing elements 16 shown. These are a) propeller stirrers, b) Disc stirrer, c) toothed disk stirrer, d) inclined blade stirrer, e) Impeller stirrer, f) anchor stirrer, g) lattice stirrer or blade stirrer, h) Crossbar stirrer, i) MIG stirrer and k) helical stirrer. Basically you can these types of mixing elements alone, in combination or modification be used. Preferably, however, the mixing element should be so be designed that it produces as little resistance in the concrete.

FIG. 8 shows a further embodiment of the mixing chamber 9. in the Mixing chamber are on the shaft 12 a plurality of stages of mixing elements 16 as Arranged helical stirrer. About the shaft 12 and the mixing elements 16 is added to the concrete admixture 5 during cross-mixing. These Design of the mixing element produces little resistance in the concrete and allows a uniform admixture of the additive. Of course you can when using a helical stirrer also two or more Nested spiral agitators are used to allow the Mixing is improved and the addition of additives over the entire cross section is made possible.

FIG. 9 shows a further embodiment of a mixing chamber 9. in the Mixing chamber are two shafts 12 with multiple stages of mixing elements 16th arranged in the flow direction. The two shafts 12 rotate thereby preferably against each other and the mixing elements can interlock, but without touching. In Fig. 10 is the Interlocking of the mixing elements shown in detail. On the right Page is schematically the effect of this mixture, that is the stretching and wrinkles, or the fine distribution of the additive shown in the concrete. Of course, any number of other waves can be used become.

FIGS. 11 a and 11 b show a further embodiment of the mixing chamber 9 shown. The shaft 12 'for driving the mixing elements 16' is not here Mixing room arranged, but outside. By means of the shaft 12 ', which over a drive 13 is driven, are rotating around the mixing chamber Mixing elements 16 'driven. The drive is advantageously over the shaft 12 'arranged gears 18, which in the ring gear 19 of the Engage mixing elements 16 '. The actual mixing elements protrude into the concrete conveyed through the mixing room and mix the concrete and the additive, especially in the periphery. How far the Mixing elements hineineragen, must be adapted to the particular circumstances be such. the plastic-viscous mixture, the geometry of the Mixing room, etc .. About the mixing elements 16 'can also here the concrete Add additive 5 during cross-mixing. These Design of the mixing element produces little resistance in the concrete and allows a uniform admixture of the additive.

Of course, the invention is not limited to the one shown and described Embodiment limited. Instead of the activator can be any Additives or other substances that are used in relatively small amounts Quantities should be mixed in a plastic-viscous mixture. Also the plastic-viscous mixture to be used is arbitrary per se. Consequently For example, such mixing devices as those set forth above can not only for the admixture of additives in concrete, but also wherever something has a mixture with plastic-viscous behavior must be mixed. Applications are thus in the construction industry, Oil refining, pyrometallurgical addition in the extraction of metals Ores, alloying metals, pasta production, introduction of Additives in doughs, for example of nuts in bread, berries, etc. in Yoghurt, plastic processing, emulsifying aromatic oils into various Food, honey processing, chemical industry, pharmaceutical industry, Colorant industry, etc .. Especially in ceramic production by means of Schlickerguss the sludges are transported to the ceramic factory and the Slip before casting a Thyxotropierungsmittel added.

LIST OF REFERENCE NUMBERS

1

transport vehicle

2

container

3

pump

4

management

5

Additive / activator

6

mixing device

7

management

8th

feed pipe

9

mixing room

10

Concrete delayed

10 '

Concrete activated

11

Grob distribution means

12

wave

12 '

wave

12a

Bearing shaft

13

drive

14

injection means

14 '

injection means

14a

injection means

15

jet

16

mixing element

16 '

mixing element

17

static mixing elements

18

Gear on shaft

19

Sprocket 16 '

20

processing site

Claims (15)

Mixing device (6) for admixing an additive in a pumpable mixture (10) with plastic-viscous behavior, in particular concrete, wherein the mixture is conveyed in a line (4, 8),
characterized in that in the line (8) at least one injection means (14, 14 ', 14a) for adding additive (5) in the mixture (10) is arranged, and that downstream of a mixing chamber (9) is arranged, in which the admixture (5) is dynamically mixed with the plastic-viscous mixture (10). Mixing device according to claim 1,
characterized in that in the mixing space at least one rotatable mixing element (16) is arranged. Mixing device according to claim 2,
characterized in that the mixing element (16) is arranged on a shaft (12) and that the drive (13) of the shaft is arranged axially to the shaft. Mixing device according to claim 2 or 3,
characterized in that the rotatable mixing element (16) is a helical stirrer. Mixing device according to claim 2, 3 or 4,
characterized in that the mixing element (16) comprises means for adding additive (5) into the mixture (10). Mixing device according to one of the preceding claims,
characterized in that in the mixing space at least one static mixing element (17) is arranged. Mixing device according to one of the preceding claims,
characterized in that the injection means (14, 14 ', 14a) are arranged in the flow of the plastic-viscous mixture (10). Mixing device according to one of the preceding claims,
characterized in that the injection means (14, 14 ', 14a) have nozzles (15) which are directed substantially downstream. Mixing device according to one of the preceding claims,
characterized in that the upstream of the mixing chamber (9) arranged line (8) is angled. Mixing device according to one of the preceding claims,
characterized in that the pumpable mixture (10) with plastic-viscous behavior is a granular suspension mixture such as concrete. Method for adding an admixture (5) to a pumpable mixture (10) having plastic-viscous behavior, in particular concrete, the mixture being conveyed in a duct (4, 8),
characterized in that the additive (5) to the pumpable mixture (10) via at least one injection means (14, 14 ', 14a) is present and then in a downstream dynamic mixing space in the pumpable mixture (10) is mixed. Method according to claim 11,
characterized in that the additive (5) is added by means of the injection means (14, 14 ', 14a) at a plurality of points distributed over the cross section of the conduit. Method according to claim 11 or 12,
characterized in that additive (5) is added in the dynamic mixing chamber. Method according to claim 13,
characterized in that the additive (5) is added via at least one mixing element (16) arranged in the mixing chamber. Method according to claim 14,
characterized in that the additive (5) via the shaft of the mixing element (16) is conveyed to the mixing element.

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