DE102011102988A1 - Slurry mixer has upper agitation zone and lower dispersing zone, where dispersion zone has smaller volume than agitation zone - Google Patents

Abstract

The slurry mixer (1) has an upper agitation zone (2) and a lower dispersing zone (3), where the dispersion zone has a smaller volume than the agitation zone. A mixing tool (7) with a stirring shaft and mixing paddles (9) is provided in the dispersing zone, where a separating element (4) is provided for agitation zone and dispersing zone. An outer passage (6) is controlled from the outside surface during the mixing process. An independent claim is included for a method for manufacturing slurry in the slurry mixer.

Description

The invention relates to a suspension mixer and to a process for the preparation of suspensions.

Suspension mixers are known per se. From the DE 10354888 A1 is a suspension mixer, there referred to as a colloidal mixer, and a method for producing a colloidal mixture described. The mixer has an upper, larger volume premix and a lower volume dispersion zone and a two-part separator comprising a guide ring and a baffle plate which spatially delimits the different zones. The premix and dispersion zones are each equipped with separate agitators. The stirring paddles of the dispersion zone press the mixture against the baffle plate, which is arranged above the stirring paddle zone of the dispersion zone and has a circular recess in the center. The mixture subsequently strikes the guide ring, which is arranged above the baffle plate and with respect to its outer and inner diameter is smaller in diameter than the baffle plate. The mix moves along the guide ring outwards and upwards and is in this case pressed by a circumferential outer annular slot between the guide ring and the mixer inner wall in the premixing zone. The mix then falls together in the middle of the premixing zone and thus passes through the first separating element, the guide ring seen from above, back into the dispersing zone.

It has now been found that the arrangement of the guide ring and baffle plate is not suitable for every mix and allows little flexibility to process different mix. For this purpose, the mixer must be rebuilt in each case, with the separating elements are replaced. This is impossible during a mixing process and also not advantageous due to the time required in practice between two or more mixtures.

Another disadvantage is that the mass transfer between the two zones during a mixing process by the separating elements of DE 10354888 A1 can not be varied. This leads inter alia to longer mixing times as far as certain grain size or grain size distributions are desired.

With changing ingredients of the suspension, as is often the case in the production of suspensions for concrete production, in the suspension mixers known from the prior art, the optimum state for each material flow and processing time can not be set. Moreover, the processing intensity in the premixing and / or dispersing zone during the preparation of the suspension can not be influenced. During the preparation of the suspension, it is also not possible to influence the changing liquid / solid contents and the dosage of different ingredients with different densities and the respective viscosity.

The object of the invention is u. a. It is to provide a set-up with which it is easier to respond to the different requirements of the mixing process, as it results on the one hand by different starting mixtures, on the other hand by the change of the mix during the mixing process.

It has now surprisingly been found that this object is achieved by the subject matter of the independent claims. Preferred embodiments are subject of the dependent claims and / or described below.

The suspension mixer according to the invention has an upper, larger-volume circulation zone and a lower, relatively smaller dispersion zone, and at least one optionally multi-part separation element which delimits the different zones spatially. The dispersion zone is equipped with a mixer. The mixing paddles of the dispersion zone press the mixture either directly or indirectly against the separating element. The mixture is pressed through the mixing unit of the dispersion zone against the separating element and along and / or therethrough to the outside and / or above into the above the dispersing zone arranged Umwälzzone.

The volume of the recirculation zone in a preferred embodiment is at most 10 times the volume of the dispersing zone, ideally the volume ratio of dispersing zone (A) to recirculation zone (B) is 1 (A) to 4 (B) to 1 (A) to 8 (B ). Independently and in other words, when the mixing process is interrupted, mixed material in the dispersion zone (A) and mixture in the circulation zone (B) are in a volume ratio of 1 (A) to 4 (B) to 1 (A) to 8 (B) ,

In the dispersing zone, preferably 3 to 6 mixing paddles are provided. With regard to the mixing paddle length (radially from inside to outside), the mixing paddles preferably occupy greater than 30%, in particular greater than 30 to 50%, of the radius of the dispersion zone. The mixing paddles preferably have a plurality of openings.

The (mean) diameter ratio of dispersion zone (A) to circulation zone (B) is preferably greater than 0.5 (A) to 1 (B), ideally the diameter ratio of dispersion zone to circulation zone is 0.6 (A) to 1 (B) to 0, 9 (A) to 1 (B).

The ratio of the volume of the circulation zone in dm ³ to mixing paddle displacement area (area without passages) in dm ² is preferably less than 100, ideally less than 50.

The ratio of the total mixing paddle area (A) (total area with the passage areas attributed to the total area) to the sum of the passage areas of the mixing paddle openings (B) is preferably 1 (A) to less than 0.6 (B), ideally 1 (A) too small 0.4 (B).

The separator has means for controlling the amount of passage per unit time and hence the exchange between dispersing zone and circulating zone, i. H. to change and control the flow rate as well as the flow resistance during the manufacturing process of the suspension. By this possibility, the processing time and processing intensity in the dispersing zone can also be optimized controlled and adjusted during the mixing process. Depending on the quality and quantity of the ingredients and viscosity of the suspension, it may be advantageous to increase or decrease either the flow rate, the flow resistance or both.

Also with regard to the production time, it is advantageous to set a high / maximized material flow from the dispersion zone into the circulation zone, for example at the beginning of the mixing process or when adding new ingredients to the mix. H. to increase the passage areas of the outer passage, and to reduce towards the end or during metering the passage area and thus the flow of material.

It has been shown that for suspension mixers with a controllable flow rate between the dispersing and circulating zones, the production time of a suspension can be shortened considerably compared to mixers with immobile separating element, which also reduces energy consumption and additionally increases the amount of suspension produced per unit time.

• • einen mittleren Durchlass, der im Bereich über der Achse der Mischwerkzeuge der Dispergierzone angeordnet ist,
• • einen äußeren Durchlass, der zumindest teilweise über den Mischpaddeln und/oder seitlich neben dem äußeren Umfang der Mischpaddel des/der Mischwerkzeuge der Dispergierzone angeordnet ist. Die Durchtrittsfläche des äußeren Durchlasses ist veränderlich. Der Durchlass kann aus einer oder mehreren Durchtrittszonen bestehen.

The separating element between dispersing and circulating zone can be formed in one or more parts and is arranged above the mixing paddles of the dispersing zone and below the circulating zone. The separating element (s) always has / have:

• A middle passage, which is arranged in the area above the axis of the mixing tools of the dispersion zone,
• An outer passage arranged at least partially over the mixing paddles and / or laterally next to the outer periphery of the mixing paddles of the mixing tool (s) of the dispersing zone. The passage area of the outer passage is variable. The passage may consist of one or more passage zones.

The one- or multi-part separator may have a plurality of apertures in the (eg, substantially horizontal) surface of the separator (s), the apertures being disposed over the mixing paddles and causing buildup on the surface of the separator (s) to be removed because the flowable medium is forced through the openings at high speed and removes possible adhesions.

At least one of the separating elements or separating element parts is movable and according to a first embodiment releases on its outer circumference a passage between the separating element and the mixer inner wall, which is preferably in the form of all or part of a circumferential slot between the separating element and the mixer inner wall and the slot provides a passage surface of variable size.

According to the first aspect, the partition member comprises an upwardly movable partition ring for releasing an outer annular gap between the outer partition periphery and the inner wall of the mixer tank.

For this purpose, the inner wall of the container in the region of the outer Trennringumfangs outward on a conical widening, so that decreases with lowered separating ring of the outer annular gap, possibly to zero or almost zero, and increases when lifting the separating ring, the annular gap. The separator ring has one or more apertures internally to return material from the recirculation zone to the dispersion zone. At the same time, a stationary, possibly provided with openings, storage ring is preferably provided as a further constituent of the separating element, in particular directly above the mixing paddles of the dispersion mixing, possibly also partially on the upper inner circumference of the mixing paddles, circumferentially with vertical surface portions. The storage ring is arranged between mixing paddle and movable separating ring. The movable separating ring can, for. B. be arranged on one of two intermeshing and movable away from each other pipes.

According to another second embodiment, the separating element is in turn formed in two parts and the position of the two parts of the separating element regulates the passage by recesses in the different separator elements are aligned or moved against each other moved away from each other to reduce the passage areas.

This is z. B. according to an embodiment that the separating ring is movable and moves only in one plane. According to this embodiment, the separating element is formed from the stagnation ring and separating ring, wherein the stagnation ring is arranged at least partially over the mixing paddles of the mixing tool of the dispersing zone and the stagnation ring and separating ring have a plurality of outer passage zones as part of the outer passage from the dispersing zone into the circulating zone. The total provided passage area of the passage zones of the separating element is variable during operation of the mixing tool. For this purpose, the separating ring is arranged to be movable relative to the storage ring, storage ring and separating ring have openings and the openings are aligned one above the other, for. B. by turning to provide multiple passage zones with a total of variable passage area. Separating ring and storage ring are preferably aligned plane-parallel to each other.

While pumping it may be z. B. be advantageous to completely close the passage zones of the outer passage, but at least to downsize in order to increase the pumping power (the mixing paddle in the dispersing) during emptying. Also, the locking ring has a hole in the middle to ensure the material backflow from the circulation zone into the dispersion zone.

According to a third embodiment, the separating element has at least two parts, wherein at least one part is movable toward the other or away from it with vertical path portions. When moving away from each other give both parts an enlarged passage area and when moving together the parts a reduced passage area free. The passage area is thus variable during operation of the mixing tool.

According to the third embodiment, the movable part (s) of the at least two-part partition member (s) are moved relative to each other, so that both parts change their distance from each other at least partially in the vertical direction. Hereinafter, at least the storage ring disposed above the mixing paddles has outer openings and the storage ring or both are spaced from one another to provide passage areas with variable passage area radially outward. According to the third embodiment, preferably the separating ring and possibly also the retaining ring have angled surface elements (eg cone-shaped surface elements) which engage in apertures of the respective other ring and partially penetrate when the separating ring or the retaining ring are moved toward one another so as to reduce the passage zones in their (total) passage area. The separating ring can, but must have no openings. The separating ring is arranged above the storage ring.

The separating element can be embodied such that a part, in particular the holding ring, is arranged on a fixed or rotatable first tube, which is located centrally in the vertical, at least partially in the dispersing zone and / or the circulating zone. In addition, a scraper, a mixer and / or a mixing tool can be attached to the tube.

In any case, at least the separating element or a part of the separating element at any time during the mixing process from the outside directly or indirectly (possibly electrically) movable and controllable to vary the material flow between the dispersing and the Umwälzzone and / or to prevent.

Dispersing and recirculation zones can have independently acting and controlled mixing tools. This allows the peripheral speed in the mixer in the dispersing and Circulation zone are regulated differently. Possibly. can be provided in the circulation and no mixing plant or merely a scraper, which attachments, z. B. on the mixer inner walls or the passage area (s) of the separating element detaches.

The improvement in the properties of the mix results z. B. in the length of time required to produce a high quality suspension. When producing a suspension for concrete, the objective may be an improved slump (indicating the degree of processability), a longer processability and / or increasing the compressive strength in the various phases in the hourly range or after a final test period of 28 d (i.e. = Days), 56 d or 90 d of the final product.

Comparative blends with a suspension mixer, in which compared to the DE 10354888 A1 has been made the ability to change by moving separating element (s) e the flow conditions between the mixing / dispersing and Umwälzzone during the preparation of the suspension, achieve significant improvements in the digestion of the ingredients and additionally expand the application of such suspension mixers as compared in addition Suspensions with higher viscosity can be produced. It has been found to be particularly advantageous that the material flow between the mixing / dispersing zone and circulation zone can be adjusted by movable separating elements during the preparation of the suspension, ie a material flow can also be prevented and / or at the beginning of the preparation of the suspension, ie when dosing the ingredients, an almost uninfluenced material exchange by the largest possible opening of the / the separating elements can take place.

In principle, it should be noted that with larger passages in the separating element also higher viscosities tend to be processed, as long as the suspension basically has a flow behavior.

The mixing tools / mixing paddles should be easily interchangeable, the passages in the mixing paddles can have different geometric shapes. The drive of the mixing tools should advantageously be variable in speed. The drive of the mixing tools or mixing tools and / or Randabstreifer in the Umwälzzone should have its own drive and advantageously be equipped with the ability to go in both directions, ie forward and backward, to brake and / or run free from the drive to be able to.

As a mix are used in slurry in addition to water in particular binder, having z. As cement, water glass, gypsum and / or calcined lime, preferably at least cement. "Gypsum" in the language of this application refers to the naturally occurring gypsum rock, the corresponding products of industrial processes (including anhydrite) and the products resulting from the burning of these raw materials. "Cement" in the context of this invention is an inorganic, finely ground material that automatically solidifies after mixing with water as a result of chemical reactions with the mixing water and hardened (hydraulic setting) and remains solid and stable even after hardening under water. Chemically, it is mainly siliceous calcium with proportions of aluminum and iron compounds, which is present as a complicated mixture. The binder may also contain fly ash, blastfurnace slag and microsilica in addition to the above ingredients.

In particular, the mix comprises less than 15% by weight of the aggregate of the hydraulically setting finished product made by mixing the mix obtainable as a binder concentrate from the suspension mixer with substantially the further aggregate in conventional mixers. As a part mixed material prepared in the suspension mixer, preferably only aggregate having a diameter of less than 4 mm (sieve analysis) is used.

As additives may be added concrete plasticizers, retarders, solidification accelerators, hardening accelerators, flow agents, air entraining agents, sealants and / or stabilizers.

Mention may be made after as a concrete plasticizer polycarboxylates, in particular polycarboxylate (PCE), lignosulfonates (also lignosulfonic acid), melamine-formaldehyde sulfonates, naphthalene-formaldehyde sulfonates, hydroxycarboxylic acids and their salts (concrete liquefier).

Furthermore, surfactants, such as. B. surface-active substances based on modified natural products, such as Wurzelharzseifen (air entraining agent), and in addition emulsions reactive siloxanes / alkylalkoxysilanes, fatty acids, fatty acid salts, polymers (resin dispersions), color pigments and mixtures thereof. In addition, lightweight aggregates such as fibers, Styrofoam, expanded clay, ground waste rubber, possibly in mixture, may be part of the mix.

The invention is explained with the following drawings, without being limited thereto. Show it:

1 a supension mixer according to the first embodiment of the invention

1a and 1b different Trennelementstellungen for the supension mixer after 1 .

2 after the supension mixer 1 with motorized height adjustment of the separating element and

3 the second embodiment of the invention, according to which the separating element consists of a storage ring and a separating ring, wherein the left half of the openings are aligned, centrally aligned completely and not shown right aligned.

In 1 is a supension mixer 1 shown. In this are circulation zone 2 and dispersing zone 3 through a separating ring 4 demarcated. This center has a middle passage 5 for the return of mix from the recirculation zone in the dispersion. At the outer circumference of the separating ring 4 becomes an outer circumferential passage 6 released in the form of a gap. The mixer 7 pushes the mix through the gap into the circulation zone 2 , In the circulation zone 2 are baffles 8th provided that the mix in the middle of the circulation zone 2 to steer. The baffles 8th can be adjusted from the outside by motor in their stop angle.

In 1a is a semi-open partition element position for the supension mixer 1 shown. About the mixing paddling 9 is one with breakthroughs 10 provided sewer ring 11 intended.

Inside, the jail ring is running 11 in a vertical area 12 out, which is guided vertically downwards and behind the paddle surfaces engages or is supplemented by this as a separate component. Similarly, the separator ring has a vertical surface 13 on. In 1b is the passage 6 minimized and the outer circumference of the separator ring 4 guided close to the inner surface of the suspension mixer. At the outer circumference of the separating ring 4 expands the inner circumference of the slurry mixer to the passage 6 The enabling of.

2 shows a possible construction of the suspension mixer 1 in the also the pipe work 14 shown is the separator ring 4 to move in height, as well as a platform on the suspension mixer 1 together with an electric motor for driving the mixing paddles 9 is arranged.

3 shows the second embodiment of the invention, after which the separating element zweeilg of a separating ring 4 and a jail ring 11 is formed. separating ring 4 and jail 11 are arranged directly above one another and each have apertures ( 15 . 16 ), which are to be brought by misalignment along a common axis to align (shown in the middle), are completely separated (shown right) or partially aligned (left), so each passage surfaces partially (shown left), whole (shown in the middle) or not (shown on the right).

Examples of preparing suspensions containing binders are shown below.

Example 1: cement suspension

In a colloidal mixer after DE 10354888 A1 (Mixer 1 ) and comparative in a suspension mixer according to the invention as in 1 and 2 were prepared under identical conditions and ingredients cement suspensions prepared with the following recipe. The slump on the Hägermanntisch as a guideline of processability and viscosity was tested immediately. The compressive strength on the basis of 3 prisms was checked from the average value after 3 days. In suspension production with mixer 1 was worked with a mixing time including dosage of the ingredients of 240 sec.

In suspension production with mixer 2 was worked with a mixing time including dosage of the ingredients of 180 sec. In the suspension mixer, the distance between the cutting disk and the mixing zone with respect to the colloidal mixer was changed from 12 mm to 40 mm at the beginning of suspension production and to 24 mm after 90 seconds.

As a result, a 27% improved processability, a 12% improvement in compressive strength and a 25% reduction in mixing time can be seen. Table 1 W / Z value 0.30 Mixer after DE 103 54 888 A1 Mixer according to invention test series 389 389 Mixing quantity in l 15 15 Water in l 7,154 7,154 Plasticizer PCE in kg 0.162 0.162 Cement in kg 23.845 23.845 Mixing time in sec 240 180 Slump in mm 180 229 3 d pressure values N / mm ² 75.59 84.7 AB change in% 27.22% Pressure change in% 12.05%

Example 2: Cement / fly ash suspension

In a colloidal mixer after DE 10354888 A1 and comparing a suspension mixer after 1 Cement / flyash suspensions with the following formulation were prepared under identical conditions and ingredients. The slump on the Hägermanntisch as a guideline of processability and viscosity was tested immediately. The compressive strength on the basis of 3 prisms was checked from the average value after 3 days. In the preparation of the suspension with the colloidal mixer according to DE 10354888 A1 was worked with a mixing time including dosage of the ingredients of 240 sec.

In the suspension production with the mixer after 1 was worked with a mixing time including dosage of the ingredients of 120 sec. At the mixer after 1 The distance between cutting disc and mixing zone with respect to the mixer was after DE 10354888 A1 changed from 12 mm to 40 mm at the beginning of the suspension production and to 24 mm after 60 sec.

As a result, a 33% improved processability, a 12% increase in compressive strength and a 50% reduction in mixing time can be seen. Table 2 W / B value 0.34 (factor 0.4) Mixer after DE 103 54 888 A1 Mixer according to invention test series 389 389 Mixing quantity in l 15 15 Water in l 7,014 7,014 Plasticizer PCE in kg 0.13 0.13 Cement in kg 19.079 19.079 Fly ash in kg 3,928 3,928 Mixing time in sec 240 120 Slump in mm 188 251 3 d pressure values N / mm ² 65,55 73.7 AB change in% 33.51% Pressure change in% 12.43%

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10354888 A1 [0002, 0004, 0031, 0050, 0052, 0053, 0054, 0055]

Claims (9)

Suspension mixer ( 1 ) having an upper circulation zone ( 2 ) and a lower dispersion zone ( 3 ), wherein the dispersion zone ( 3 ) has a smaller volume than the circulation zone ( 2 ), in the dispersion zone ( 3 ) at least one mixing tool ( 7 ) with stirring axis and mixing paddles ( 9 ) is provided and at least one separating element ( 4 ) Circulation zone ( 2 ) and dispersing zone ( 3 ) spatially delimited from each other and the separating element ( 4 ) at least one outer sleeve remote from the passage ( 6 ) and an internal near-passage ( 5 ), the inner passage ( 5 ) the material flow from the circulation zone ( 2 ) in the dispersion zone ( 3 ) and the outer passage ( 6 ) the material flow from the dispersion zone ( 3 ) in the circulation zone ( 2 ) and the outer passage ( 6 ) above the level of the mixing paddles ( 9 ) and / or laterally adjacent thereto, wherein at least the outer passage ( 6 ) in its passage area controllable from the outside during the mixing process is changeable. Suspension mixer according to claim 1, wherein the outer passage ( 6 ) as a slot between the separating element ( 4 ) and mixer inner wall is pronounced, in particular circular slot. Suspension mixer according to claim 1 or 2, wherein the separating element ( 4 ) upwards from the mixer ( 7 ) is movable away and an outer passage ( 6 ) and between the outer separating element circumference and the inner wall of the suspension mixer in the region of the outer separating element circumference, a conical widening in the inner circumference of the suspension mixer (FIG. 1 ) is given, so that when lowered separating element ( 4 ) the outer passage ( 6 ) and when lifting the separating element ( 4 ) the passage ( 6 ), in particular in the form of an annular gap, increased. Suspension mixer according to claim 1 or 2, wherein the separating element ( 4 ) is formed in several parts and at least one storage ring ( 11 ) with openings ( 15 ) and at least one separating ring ( 4 ) with openings ( 16 ) and at least one of the rings is movable relative to the other from the outside and the storage ring ( 11 ) at least partially above the mixing tool of the dispersion zone ( 3 ) and the separating ring ( 4 ) at least partially over the storage ring ( 11 ) is arranged and the separating ring ( 4 ) by a relative movement relative to the storage ring ( 11 ) Passages ( 6 ) opens or closes. Suspension mixer according to claim 4, wherein the storage ring ( 11 ) and the separating ring ( 4 ) Breakthroughs ( 15 . 16 ) and Stauring ( 11 ) and separating ring ( 4 ) are pushed one above the other to the openings ( 15 . 16 ) with passage surfaces aligned over each other to passages ( 6 ) with total enlarged passage areas. Suspension mixer according to claim 4, wherein the separating ring ( 4 ) and / or the storage ring ( 11 ) Comprise engagement elements, in particular the separating ring ( 4 ), which penetrate the openings ( 15 . 16 ) engage the other ring and at least partially immerse when separating ring ( 4 ) and / or storage ring ( 11 ) are moved towards each other so as to create passage zones with smaller (total) Druchtrittsfläche. A process for producing a suspension in the suspension mixer according to at least one of the preceding claims, wherein a mix is introduced and at the beginning of the mixing process or when adding new ingredients to the mix increased material flow from the Dipergierzone ( 3 ) in the circulation zone ( 2 ) by increasing the passage area (s) of the outer passages ( 6 ) and after completion of the metering, the passage area (s) ( 6 ), possibly with a time delay, is reduced (s). The method of claim 7, wherein during the mixing process, the rotational speed of the mixing paddles is changed controllable from the outside. A method according to claim 7 or 8, wherein the mix comprises a) water b) hydraulically setting binders, in particular cement, and c) additives, especially concrete plasticizers.

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