AT523366A1 - Mixer of a continuous mixing plant - Google Patents

Abstract

The invention relates to a mixer (5) of a continuous mixing plant for the production of a foamed slurry, in which continuous mixing plant solids and mixing liquid are mixed in a first mixer (3) with a mixing tool (3.1) to form a flowable slurry, the flowable slurry directly into the first, front end of the housing (5.3) of the mixer (5) is pumped pressure-tight, the housing (5.3) at the first, front end has a foam inlet opening (5.3.2) to which the line of a foam cannon is connected pressure-tight, in Mixer (5) a rotatable mixing tool (5.1) is arranged horizontally in the housing (5.3), the mixer (5) has an outlet opening (5.3.3) at its second, rear end.

Description

description

The invention relates to a continuous mixing system which is used to mix powdery and / or granular solids with a liquid to form a slurry (pulpy mass) and to mix this

Foaming up the slurry.

The advantages of the continuous mixing plant according to the invention are particularly valuable when the foamed slurry produced with it is a self-hardening mass, in particular a rapidly hardening mass, for example a mineral formulation such as foam concrete, or a foamed mineral thermal insulation material

is.

One problem with mixing powdery and / or granular solids with liquid to form a self-curing foamed slurry is that the slurry and the foam must be thoroughly mixed without destroying the foam structure.

ren.

Another problem is that after the discharge from the mixer has ended, a residue of slurry remains as an adhesion in the mixer and hardens there if the mixer is not cleaned promptly. By using a continuous mixer, with the help of which you can mix continuously over a longer period of time - and not having to mix in individual separate batches with downtimes in between - the cleaning effort is reduced, but here too, after the discharge or at

cleaning can be carried out if the mixer stops unexpectedly.

Typical continuous mixers for the production of self-hardening slurry from powdery and / or granular solids and water have a conveying device and a mixer, the conveying device continuously moving the solids through an opening into the chamber of the mixer, with liquid entering the mixer chamber through at least one additional opening Chamber of the mixer is introduced, wherein the mixer mixes continuously and the slurry continuously formed in the mixer

naturally flows out of the mixer through another opening.

page 1

There are many methods and devices known from the prior art for adding a foam component or compressed air to the slurry in order to produce a foamed or air-pore-containing one

Obtain building materials.

DE 3100443 A1 shows a continuous mixer for concrete or foam concrete, in which the solids are transported via a screw conveyor from the bottom of a loading container into the chamber of a horizontally arranged mixer. The screw conveyor and the rotor of the mixer lie on a common shaft and are driven jointly by a motor. Mixing water is added in the front part of the mixer and the slurry is mixed. Then foam is added in the rear part of the mixer and mixed into the slurry. From the mixer outlet, the foamed slurry arrives in the storage tank of a pump, with which the foamed slurry is pumped to the place of use. The disadvantage of this inherently robust and simple design is that the foamed slurry produced in the mixer by lifting it under is transported by a pump arranged after the mixer, which means that there is a risk of the foam structure in the pump or by pumping gets destroyed. In addition, the mixer can only be emptied when the screw conveyor has already run empty. Rapid, unplanned shutdown, as required in the event of malfunctions in any part of the system

can be, leads to considerable problems.

DE 3629674 A1 and WO 2011044604 show similar continuous mixers, although the screw conveyor and mixer rotor do not have a common shaft and can be driven separately from one another. This means that the mixer can be emptied if only the screw conveyor and the other material supply are switched off. When cleaning the mixer, which usually takes place by spraying cleaning liquid into the mixing chamber, cleaning liquid can, however, also get to the conveyed material located at the mixer-side end region of the conveyor screw and with it

form this a self-hardening mass.

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WO 2011106816 A1 shows a mixing plant for producing a mineral foam, in which a flowable slurry is mixed in a first mixing section and mixed with foam in a second mixing section. As far as can be inferred from the general description of the system, both mixing sections are arranged horizontally and there is no eccentric screw

pump available.

EP 1065033 A2 shows a continuous mixer in which the powdery and / or granular solids are introduced from above into a vertical mixing chamber and not from one side into a horizontally arranged mixing chamber as in the aforementioned documents. An eccentric screw pump is connected to the lower end of the mixing chamber, which is used to transport the slurry to the place of use. When the mixer is cleaned by sprayed-in liquid, the risk of liquid reaching powdery and / or granular solids that are not yet in the mixing chamber and forming a hardenable mass with them is thus somewhat reduced. Due to the design, in particular the vertical alignment of the material flow through the mixing chamber and the directly following delivery by the pump without an intermediate container, the amount of slurry produced can be set within a wide range and the amount of

Slurry in the system can be reduced.

DE 2437231 A1 shows a vertical mixer which has an eccentric screw pump at the lower end. In the middle of the eccentric screw pump, which is preferably designed in two stages, compressed air is added to the slurry. On the output side, the eccentric screw pump is followed by a vortex chamber in which a rapidly rotating tool continues to mix the slurry mixed with compressed air. The disadvantage is that the agitator tool is mounted vertically in the vortex chamber and rotates quickly, which means that the mixing distance in the vortex chamber is limited to the diameter of the agitator tool and the brief, vigorous mixing can have a negative impact on the structure of the air pores.

the.

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DE 3807250 A1 shows a continuous mixer for mixing a slurry and a foam component. The mixer is fed with slurry via the hose line of a concrete pump, with the foam also being injected into the mixer. The disadvantage is that a premixed slurry is used, which is transported to the storage tank of a concrete pump and from there via a hose line to the mixer. The device shown is therefore suitable for use on a construction site in which a certain distance has to be overcome between the pump and the place of use. For the production of prefabricated components such as thermal insulation panels from rapidly hardening foamed slurry, this prerequisite

direction unsuitable.

DE 4408088 A1 shows a method for producing a porous mineral light insulation board. A slurry is mixed in a first mixer, which enters an intermediate container and is transported away by a pump via a line. The line of the slurry and the line of the foam component are combined via a Y-shaped branched mixing tube and homogenized by a static mixer. A static mixer has no rotating parts. The mixing takes place through static obstacles, which cause turbulence in the components. The disadvantage is that the mixing in the static mixer cannot be adapted to a variable delivery rate. In addition, cleaning the static mixer turns out to be difficult, since material cannot be discharged from the static mixer when the pump is at a standstill. In addition, a rapidly hardening compound tends to stick to the complexly shaped obstacles in the static mixer, with areas behind the obstacles only being caused by water which is pumped through the static mixer under pressure

are difficult to clean.

The object on which the invention is based is to provide a continuous mixing plant for the production of a very rapidly hardening

to create highly foamed slurry. Sub-tasks of the invention can be seen in the fact that it is in

the continuous mixing plant does not harden the slurry,

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the amount and density of the foamed slurry produced should be adjustable over a wide range, gentle foaming of the slurry is made possible, destruction of the foam structure is prevented, production can be stopped at any time without major problems and the system

can be cleaned quickly during continuous operation.

To solve the problem, the invention proposes to mix solids and the mixing liquid to a flowable slurry in a first vertically arranged mixer, with an eccentric screw pump being attached to the lower end of the vertical mixing chamber, which transfers the premixed material from the first mixing chamber under pressure directly into the Conveying the starting area of a second mixing chamber, the second mixing chamber being arranged horizontally and having a rotating, horizontally arranged elongated mixing tool. The foam component is also conveyed under pressure via a foam cannon into the starting area of the horizontal mixing chamber, the slurry and the foam being moved through the horizontal mixing chamber, the mixing tool gently adding the foam component to the slurry. It is important that the connection of the foam cannon and the eccentric screw pump to the horizontal mixer is pressure-tight.

leads are.

The amount of slurry and foam is preferably selected so that the conveyance through the horizontal mixing chamber takes place mainly through the higher volume flow of the foam. The amount of slurry which is pumped into the horizontal mixer is preferably between 1 and 12 liters per minute, particularly preferably an amount of 2 to 9 liters / minute. The amount of foam which is pumped into the horizontal mixer is preferably between 30 and 200 liters / minute, particularly preferably between 50 and 100 l / min. The ratio between the volume of the foam and the volume of the slurry is preferably between 200: 1 and 30:12, particularly preferably between 50: 1 and 5: 1. At the rear end of the horizontal mixing chamber there is an outlet opening through

which the ready-mixed foamed slurry the

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Continuous mixing plant leaves and is preferably poured directly into molds. If necessary, a hose can also be connected to the outlet opening, whereby the diameter of the hose

that should correspond to the horizontal mixing chamber.

This results in the following advantages compared to the state of the art

share:

° Since there are no intermediate stores, lines or hoses, the amount of slurry or foamed slurry that is in the mixing system is lower than with known devices and the rapid emptying and cleaning is

relieved.

® * The vertical arrangement of the first mixer prevents the inlet for the solids, which is located at the upper end of the vertical mixer, from being in the operating state

Mixing liquid comes into contact.

e The vertical arrangement of the first mixer and the vertically arranged eccentric screw pump ensures that, when the material feed is stopped and the mixing tool of the vertical mixer and the eccentric screw pump continue to operate

Cken pump, can be emptied almost completely.

e The horizontal arrangement of the second mixer ensures that the foam and thus the resulting pores are not compressed, since, in contrast to the vertical arrangement, the influence of gravity is negligibly small. This enables a very regular pore size. The influence of gravity is also negligible due to the very low weight of the foamed slurry when the preferably high proportion of foam is added.

ee Because the outlet opening of the horizontal mixer preferably opens into the open air or a hose with a large diameter and because the horizontal mixer and possibly the hose have a significantly larger diameter than the feed openings for the slurry and foam, the foam is lifted in the horizontal mixer almost pressureless, which means that the foam and thus the resulting pores are not

page 6

be compressed or destroyed. This is particularly advantageous compared to static mixers, since in these the slurry and foam are conveyed through the static mixer under pressure.

e * The rotating, elongated mixing tool in the horizontal mixer ensures that the material is also in this

a conveyor stop of the foam cannon is moved.

° The continuous mixing plant can process self-hardening slurries very quickly, because the amount of slurry in the system is as small as possible, the slurry is constantly and actively moved in every area of the plant, and the system can be emptied almost completely

and is easy to clean and dismantle.

The solids are preferably supplied by a screw conveyor, which the solids continuously from the lower end of a

Promotes reservoir to the top of the vertical mixer.

The shaft of the mixing tool of the vertical mixer preferably has a coupling at the lower end, which is in operative connection with the rotor of the eccentric pump, so that the chamber of the vertical mixer with the motor and the mixing tool mounted on it is separated from the eccentric screw pump and the solids feed

Opening moved away, in particular can be pivoted away.

Particularly preferably, the vertical mixing chamber and / or the horizontal mixing chamber have supply valves for cleaning liquid, via which cleaning liquid can be fed in under high pressure. The vertical mixing chamber preferably has high-pressure injection nozzles, via which the required process

water can be injected.

Vertical mixers with eccentric screw pumps, as are known from the prior art, can be used to implement the invention. These can be used, for example, as mortar mixing pumps (e.g. models from the PFT G4 series from Knauf PFT GmbH &

Co. KG).

With the objective use of solids, which at

Contact with liquid or moisture hardened very quickly

page 7

Form masses, the improvements according to the invention described below have proven to be advantageous. These improvements could be viewed as independent inventions, since the improvement of the individual components is also advantageous when used in other ways or in combination. In combination and when used in the present continuous mixing plant and the very rapidly hardening slurry that is preferably used, these are

particularly valuable.

The first preferred improvement according to the invention of the vertical mixer consists in the fact that an additional cover or gate valve is present. As a result, the vertical mixer can be closed in an area between the supply opening for the solids and the supply opening for the mixing liquid. After the cover or the gate valve is closed, the mixer can be cleaned with cleaning liquid under high pressure or normal pressure. The cleaning liquid is fed through the feed opening of the mixing liquid or through additional nozzles

injected.

The second preferred improvement according to the invention of the vertical mixer consists in the fact that it is designed in two parts, with mixing water not being added until the second, lower section of the mixing chamber. The two sections are formed by using a disk which has a closable opening for the solids to pass through. In the lower section of the mixing chamber there is a mixing tool which sweeps over all surface areas of the inside of the lower section of the mixing chamber at least once per revolution, so that no material can adhere to it and harden. The mixing tool located in this section preferably has two plug-in couplings for connection to the rotor of the eccentric screw pump on the one hand and to the shaft of the motor on the other hand. The housing of the mixing chamber can be opened in the lower section and the mixer

can be removed. The improvement according to the invention of the eccentric screw pump

it says that this is with its lower end in or on the housing

page 8

of the horizontal mixer is mounted so that the housing of the eccentric screw pump is secured at its lower end against horizontal displacement and torsion. Another improvement according to the invention of the eccentric screw pump can consist in the fact that it is provided at its lower end with a bearing plate for mounting the rotor, this bearing plate being connectable directly to the inlet opening of the horizontal mixer in a pressure-tight manner. The rotor of the eccentric screw pump is particularly preferably mounted directly in the mixer housing of the horizontal mixer. A part of the rotor preferably protrudes into the feed opening of the housing of the horizontal mixer, so that the

The outer surface of this opening is swept over by the rotor.

Because the eccentric screw conveys directly from above without an intermediate piece into the horizontal mixing chamber and the feed opening is swept over by the horizontal mixing tool from below, there is no sticking or hardening of material between the eccentric screw pump and the horizontal mixer. The connection of the eccentric screw pump and the mixer housing is preferably detachable, for example by means of a clamping lever, electric linear drive, or a pneumatic or hydraulic cylinder, so that the horizontal mixer housing can be removed from the eccentric if necessary.

screw pump can be moved away.

The particularly preferred improvement according to the invention of the horizontal mixer consists in that the mixing tool of the horizontal mixer consists of an elongated shaft to which elastically deformable mixing elements, preferably made of high-strength steel, are attached. These mixing elements are exposed to bending forces and vibrations during operation, which results in a change in shape of the flexible spring steel, which causes caking to loosen. This is particularly advantageous if the solids do not contain any coarse-grained particles that would otherwise

would contribute to caking.

The ends of the mixing elements are preferably in contact with the inner wall of the mixing chamber, so that they continuously strip off the material adhering to the inner wall during operation. Particularly

page 9

The mixing elements are preferably designed in such a way that all surface areas of the inner wall are stripped off with one rotation of the mixing tool. Particularly preferably, the mixing elements are made from a 0.5-1.5 mm thick spring steel sheet and against the

Pre-tensioned inner wall of the mixing chamber. The invention is explained in more detail with reference to drawings:

Fig. 1: Shows the continuous mixing plant according to the invention in a partial sectional side view.

Fig. 2: shows a particularly preferred continuous mixing plant according to the invention in a partial sectional side view.

Fig. 3: Shows the bearing plate of the eccentric screw pump in a sectional side view and from above.

4: shows a vertical mixer according to the invention with closed shut-off elements in a partial sectional side view and in a sectional view from above.

5: shows a vertical mixer according to the invention in a side sectional view.

Fig. 6: Shows the exemplary structure of a particularly preferred shut-off element in sectional view.

7: shows a particularly preferred vertical mixer according to the invention in a sectional view.

8: shows a horizontal mixer according to the invention in a view from the rear and in a side sectional view.

9: shows a further horizontal mixer according to the invention in a view from the rear and in a side sectional view.

10: shows a further horizontal mixer according to the invention in a view from the rear and in a side sectional view.

Fig. 11: Shows the particularly preferred mounting of the eccentric screw pump directly on the housing of the horizontal mini

Schers in a side sectional view. As can be seen in FIG. 1, the solid, powdery to granular solids are conveyed from a storage container 1 into the vertical mixer 3 by a conveying device 2. At the bottom

Page 10

At the end of the vertical mixer 3 is an eccentric screw pump 4. The vertical mixer 3 has at least one water connection 3.3 for introducing the mixing liquid, which can consist of water or water with various liquid additives. The water connection 3.3 is located below the feed opening for the solids, which prevents mixing

water reaches or enters the conveyor 2.

In the vertical mixer 3, the solids are mixed with the mixing liquid to form a flowable slurry, which passes from the lower end of the vertical mixer 3 directly into the eccentric screw pump 4. The shaft of the vertical mixing tool 3.1 has a connection to the rotor 4.1 of the eccentric screw pump 4, so that the shaft and the rotor 4.1 are driven by a common drive, the motor 3.2. The eccentric screw pump 4 pumps the slurry directly into the horizontal mixer 5. The slurry passes from above through the slurry inlet opening 5.3.1 in the housing 5.3 of the horizontal mixer 3 into its mixing chamber. Foam is introduced into the horizontal mixer 5 through the foam inlet opening 5.3.2 with a foam cannon. The slurry inlet opening 5.3.1 and the foam inlet opening 5.3.2 are located in the front area of the mixer housing 5.3. The mixer housing 5.3 is elongated and preferably has an annular cross-section, that is to say it is preferably shaped as a horizontal hollow cylinder which is closed at one or both ends with a disk. In the rear area of the mixer 5, the housing 5.3 has the outlet opening 5.3.3 through which the slurry mixed with foam leaves the continuous mixing plant. The horizontal mixing tool 5.1 is located in the mixer 5.3. This consists of an elongated shaft which is provided with several mixing elements 5.1.1. The shaft can be mounted on both sides of the mixer 5 in its housing 5.3. The horizontal mixing tool 5.1 is driven by the motor 5.2 and thereby rotates around its own axis. The rotation of the mixing elements 5.1.1 takes place at an angle of 90 ° to the direction of transport

of the slurry and the foam. The mixing section of slurry and foam

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is determined by the length of the mixing chamber of the horizontal mixer 5. The foamed slurry preferably passes directly from the outlet opening 5.3.3 into a mold 6 in which it can harden to form an element, in particular a plate or plate geometry. Instead of the form 6, the slurry could be filled into pre-formed components such as bricks in order to reduce their thermal insulation properties.

improve.

Fig. 2 shows a continuous mixing plant according to the invention, details particularly preferred details of the design being shown

will.

The conveyor device 2 is preferably a screw conveyor. The screw conveyor 2.1 is driven by a motor 2.2. Preferably, the screw conveyor 2.1 is somewhat in the

Mixing chamber of the vertical mixer 3 before.

The shaft of the vertical mixer 3 is preferably connected to the rotor 4.1 via a plug-in coupling. As a result, the vertical mixer 3 can be detached from the eccentric screw pump 4, in particular pivoted away from it. If the vertical mixer 3 is pivoted into the operating position, the parts of the

Plug-in coupling engaged again.

The eccentric screw pump 4 can be firmly connected at its lower end to a bearing plate 4.2, which can be made of high-strength steel, for example. The bearing plate 4.2 serves as a bearing for the rotor 4.1, since it is only connected to the shaft of the vertical mixing tool 3.1 via a plug-in coupling. For this purpose, the rotor 4.1 rests decentrally on the bearing plate 4.2 with an eccentric portion of its lower end. The vertically acting forces are transmitted from the eccentric part of the rotor 4.1 to the bearing plate 4.2. The rotor 4.1 can preferably also be mounted directly in or on the housing 5.3. The housing 5.3 can preferably be moved away from the eccentric screw pump 4 and is, for example, by means of two clamping levers or one

Pneumatic cylinder 9 can be fixed on this.

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An exemplary bearing plate 4.2 is shown in FIG. 3. The body of the support plate 4.2 is shaped as a plate with a central opening, preferably ring-shaped. An additional radial guidance of the rotor 4.1 can take place if it has at its lower end a pin which is eccentric to the axis of rotation and which runs around the outer surface of the opening of the bearing plate. The central opening could also be designed as an elongated hole that is longitudinally oval, the diameter of the pin being the width of the

Corresponds to elongated hole.

On the outer surface of the bearing plate 4, 2 or on the housing 4. By tightening the clamping lever, the horizontal mixer 5 is pressed against the bearing plate 2.4. To improve the sealing effect, a seal made of rubber or a comparable material can be placed between the bearing plate 2.4 and the housing 5.3

to be appropriate.

It is also conceivable not to attach the bearing plate 4.2 to the housing 4.3 of the eccentric screw pump 4, but to connect the bearing plate 4.2 firmly to the housing 5.3 of the horizontal mixer 5, for example by welding and using clamping means or a pneumatic cylinder 9 to connect the housing 5.3 to the bearing plate 4.2 to press against the eccentric screw pump 4. The slurry inlet opening 3.5.1 itself could also be designed with two opening cross-sections of different sizes in order to create a support surface for the rotor 4.1 in the same way as the bearing plate 4.2.

fen.

The vertical mixer preferably has a shut-off element 7. This shut-off element 7 can be moved into the mixing chamber of the vertical mixer 3 in such a way that a liquid-tight separation of the conveying device 2 and the parts of the vertical mixer 3 that come into contact with mixing liquid can be produced. This shut-off element 7 can

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for example, as a cover 7.1, the feed opening through which the conveying device 2 conveys into the mixing chamber of the vertical mixer 3, close. The shut-off element 7, as a shut-off valve 7.2, can close the vertical mixer 3 in a cross-sectional area which lies between the material supply of the solids and the water connection 3.3. For this purpose, the shut-off slide 7.2 preferably consists of two slides which can be moved horizontally into the vertical mixer 3 from two sides. In the closed state, the two end faces of the slide rest against one another, both end faces having a semicircular recess which serve to receive the shaft of the vertical mixing tool 3.1. The end faces as well as the recesses of the two slides are preferably covered with rubber or a

Equipped with the same material in order to improve the sealing effect.

4 shows the vertical mixer 3 with closed shut-off elements 7. Two variants of the shut-off element 7 are shown, with only one of the two when the device is implemented

is used.

The shut-off element 7 can be designed as a slidably held cover 7.1. This cover 7.1 can be pushed into the connecting line between mixer 3 and conveyor 2. When shutting off, the conveyor 2 is first moved a little away from the mixer 3, whereupon the cover 7.1 into the resulting gap

is moved and seals it off.

The shut-off element 7 can be designed as a gate valve 7.2. This shut-off slide 7.2 preferably consists of two slides which can be moved horizontally into the mixer 3 from two sides. Both slides have a recess with which they enclose the shaft of the vertical mixing tool 3.1 in the locked state. On the side surfaces on which the slides come into contact with one another and with the shaft, these can be provided with rubber or a comparable material

be.

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It is also conceivable to attach a gate valve 7.2 instead of the cover 7.1 in the area of the mouth opening of the conveying device. In this case it is not necessary to move the conveyor device 2 away from the mixer 3 and the gate valve 7.2 only points

open a slider.

Fig. 5 shows the particularly preferred embodiment of the vertical mixer 3 with a two-part mixing chamber. The separation into two sections is made by the partition plate 3.4. The actual mixing element 3.1.1 is arranged in the lower section of the mixing chamber. The partition plate 3.4 has an opening concentric to the shaft of the vertical mixing tool 3.1. The gap between the shaft and the partition plate forms the opening for the passage of the solids from the upper section of the vertical mi

Schers 3 in the lower section.

In Fig. 5, the shut-off element 7 is designed as an automatically adjustable sealing body 7.3, which can seal the two sections of the vertical mixing chamber. The sealing body 7.3 has a hollow cylindrical shape, which is tapered in the shape of a truncated cone at the lower and upper end. The opening in the partition plate 3.4 is funnel-shaped so that the surface of the truncated cone of the sealing body 7.3 rests against the surface of the opening in the closed state. The hollow cylinder of the sealing body 7.3 encloses the drive shaft of the vertical mixing tool 3.1, the sealing body 7.3 along the

drive shaft can be moved.

The drive shaft of the vertical mixing tool 3.1 is rotatably mounted with respect to the part of the sealing body 7.3 which rests against the partition plate 3.4 in the closed state. In this way, the mixing element 3.1.1 and the rotor 4.1 of the eccentric screw pump 4 can still be driven even after the two sections of the mixing chamber have been tightly separated. The upper section of the mixing chamber should not have any areas in which solids can be deposited, i.e. no horizontal surface areas. For this purpose, the upper section preferably has a funnel-shaped internal shape. In the example, this is achieved in that above

page 15

the partition plate 3.4 a funnel insert, for example made of plastic, is inserted into the mixing chamber. The movement of the solids through the opening of the partition plate 3.4 can be supported by a shaker or vibrator, which is located on the outside of the housing

of the upper portion of the mixing chamber is attached.

In Fig. 6 the cross section of an exemplary sealing body 7.3 is shown. This is mounted in an outer sleeve so as to be translationally displaceable. The outer sleeve is connected to the housing of the mixer, for example as shown via two webs. The outer sleeve and the sealing body 7.3 have an opening for the passage of the drive shaft of the vertical mixing tool 3.1, it being possible for seals (not shown) to be provided at these points. The sealing body 7.3 can be hydraulic, pneumatic or

be adjustable via an electric drive.

7 shows a further advantageous variant of the vertical mixer 3, in which case the conveying device 2 delivers material into a chute. This chute opens into an opening in the housing of the mixing chamber, the opening being spaced apart from the passage opening of the drive shaft of the vertical mixing tool 3.1. The drop shaft can be closed by a gate valve 7.2. The mouth opening of the chute is preferably provided diagonally opposite the water connection 3.3 in the upper side of the mixer housing. Advantages of this design are the simple structure and the simple sealable

speed.

According to the invention, at least one air pressure nozzle can be present in the transition area from the solids zone to the slurry zone of the vertical mixer 3, i.e. in the area of the mouth opening of the chute or the opening in the separating plate 3.4, which for better introduction of the powdery solids, in particular the cement

powder leads.

By closing the shut-off element 7, 7.1, 7.2, 7.3 before cleaning the continuous mixing plant, it can be ensured

that even with high pressure cleaning of the vertical mixer 3

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no cleaning liquid reaches the conveying device 2 and forms a self-hardening mass with the solids located there. This has the advantage that cleaning can take place at any time without the conveying device 2 having to be emptied beforehand

would have to.

As shown in FIG. 2, the vertical mixer 3 and / or the horizontal mixer 5 preferably has at least one nozzle opening 8, via which cleaning liquid can be sprayed, preferably under high pressure. This enables quick and automated cleaning of the continuous mixing plant. The cleaning liquid can also be injected exclusively or additionally via the water connection 3.3, the cleaning liquid subsequently being fed through the eccentric screw pump 4 in

the horizontal mixer 5 is pumped.

The foam inlet opening 5.3.2, the water connection 3.3 and the cleaning nozzles 8 have non-return valves which prevent slurry or cleaning liquid from entering one of the lines for

Foam, mixing water and cleaning liquid penetrate.

The mixing elements 5.1.1 are preferably made of high-strength steel

out, which leads to a self-cleaning effect of this.

8-10 show horizontal mixer 5 according to the invention. As shown here, the motor 5.2 is preferably not located at the rear end of the horizontal mixer 5 but at its front end, that is to say the end at which the slurry and foam are supplied. As a result, the rear end of the horizontal mixer 5 can be open, designed as an outlet opening 5.3.3. The storage of the drive shaft in the passage opening at the front end of the

Housing 5.3 must be pressure-tight.

The mixing elements 5.1.1 consist of an elastic material, in particular of high-strength sheet steel or wear-resistant plastic. The individual mixing elements 5.1.1 are preferably formed by a web which runs parallel to and at a distance from the drive axis of the horizontal mixing tool 5.1. The bridge

is about two legs, which are preferred at both ends

page 17

attach, connected to the drive shaft. Of course, more than two webs can also be provided, in particular in order to increase the stability if the web is made of thin sheet metal and / or is made very long. The mixing elements 5.1.1 are designed to be longer than the distance between the shaft and the inside of the housing, viewed radially, so that the mixing elements 5.1.1 rest against the inside of the housing and are pretensioned against it. Bending moments due to the preload on the shaft can be compensated for in that the mixing elements 5.1.1 are attached radially offset from one another, so that the radially acting forces of the preload cancel each other out. It is important that the webs of the mixing elements 5.1.1 in total sweep over the entire surface area of the inside of the housing 5.3 at least once during one revolution. Lateral top surfaces of the inside of the housing 5.3 can each be swept over by the adjacent leg of the mixing element 5.1.1 adjoining the top surface. Since all inner surfaces of the housing 5.3 are swept over during one rotation, this prevents slurry or foamed slurry from adhering to them and hardening. In areas in which two or more mixing elements 5.1.1 overlap on a circumferential area, the inside of the housing 5.3 is swept over several times per revolution. In addition to the mixing elements 5.1.1 described, for example in the area between two legs of a mixing element 5.1.1 and radially offset from this, differently shaped mixing elements 5.1.1 can also be attached to the shaft. These could, for example, be designed as high-strength steel plates, which do not extend to the inner surface of the housing

5.3 extend.

As shown in FIG. 8, the mixing elements 5.1.1, especially in the two end regions of the horizontal mixer 5, can be designed differently. At the front end of the mixing chamber, at which the slurry inlet opening 5.3.1 is located, the thickness of the spring steel sheet should be made somewhat thicker, for example 1.5 mm. In the rear end of the mixing chamber, where the

Outlet opening 5.3.3 is located, a larger number of

page 18

5.1.1 mixing elements can be provided on the same circumferential area of the shaft. In the example, these are two mixing elements 5.1.1, which are arranged at an angle of 180 ° to one another. The number of mixing elements 5.1.1 on a circumferential area could also be selected to be greater, in particular three at an angle of 120 ° to one another, four at an angle of 90 ° to one another, five at an angle of 72 ° to one another, and so on. As a result of the configuration with several mixing elements 5.1.1 arranged radially offset from one another, the horizontal mixing tool 5.1 is supported and guided in the housing 5.3, so that a separate mounting of the shaft at the rear end of the mixing chamber can be dispensed with. This allows the outlet 5.3.3 over the entire rear

Extend the side surface of the housing 5.3.

As shown in Fig. 10, the rear end of the tubular horizontal mixing chamber can be largely open, even when the shaft is supported, if an, for example, circular sector-shaped bearing plate is provided, which is connected with its one end to the housing 5.3 and in the area of the other end a Recess for

Has storage of the shaft.

As shown in FIG. 9, the legs of the mixing element 5.1.1 can be attached to the shaft, radially offset from one another. Depending on the direction of the offset with respect to the direction of rotation, the discharge of the foamed slurry is supported or

counteracted.

In a further variant, not shown, the outlet opening 5.3.3 can have a cover 7.1 or a gate valve 7.1. As a result, the horizontal mixer 5 can be closed in a sealing manner. For example, the horizontal mixer 5 can be closed during cleaning and filled with cleaning liquid which is circulated by the horizontal mixing tool 5.1. For example, the outlet opening 5.3.3 can also be closed in the periods in which a filled mold 6

is exchanged for an unfilled form 6.

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11 shows the particularly preferred embodiment in which the eccentric screw pump 4 conveys directly into the horizontal mixing chamber without a bearing plate 4.2. As shown, the rotor 4.1 can thereby preferably somewhat into the slurry inlet opening 5.3.1. The rotor 4.1 of the eccentric screw pump is not supported at its lower end. This is possible if an upward force acts on the rotor 4.1 when the eccentric screw pump 4 is in operation due to its rotational movement in the approximately helical housing 4.3. In order to secure the housing 4.3 against displacement, a ring 4.4 is welded onto the housing 5.3 of the horizontal mixer 5, which ring serves for the horizontal mounting of the eccentric screw pump 4. In order to secure the housing 4.3 of the eccentric screw pump 4 against twisting, a retaining pin 4.3.1 protrudes therefrom, which is inserted into a U-shaped retaining plate, wel-

surface is attached to the housing 5.3, engages.

As also shown in FIG. 9, a pneumatic cylinder 9 can preferably be attached to the horizontal mixer 5. Instead of the pneumatic cylinder 9, a hydraulic cylinder or an electromechanical linear drive could also be used. By means of the pneumatic cylinder 9, the horizontal mixer 5 can either be pressed against the eccentric screw pump 4 or moved away from it. The ring 4.4 has a phase at the upper edge of its opening which is used to center the eccentric screw pump

4 serves.

Since many detailed improvements according to the invention are specifically described in the description of the figures, reference should finally be made again to the basic solution according to the invention, consisting of the conveyance of a flowable slurry with an eccentric screw pump 4 connected to the lower end of a vertical mixer 3 directly into the starting area of a horizontal mixer 5, whereby the foam of a foam cannon is also pumped into the starting area of the horizontal mixer 5 and the foam and the slurry on the way through the horizontal mixer 5 to its outlet opening 5.3.3 through the rotating horizontal one

Mixing tool 5.1 are mixed.

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Claims (10)

Claims 1. Mixer (5) of a continuous mixing plant for the production of a foamed slurry, in which continuous mixing plant solids and mixing liquid are mixed in a first mixer (3) with a mixing tool (3.1) to form a flowable slurry the, characterized in that - the flowable slurry is pumped pressure-tight directly into the first, front end of the housing (5.3) of the mixer (5), - the housing (5.3) at the first, front end has a foam inlet opening (5.3.2) to which the line of a foam cannon is connected in a pressure-tight manner, - In the mixer (5) a rotatable mixing tool (5.1) is arranged horizontally in the housing (5.3), - The mixer (5) at its second, rear end one Has outlet opening (5.3.3). 2. Mixer (5) of a continuous mixing plant according to claim 1, characterized in that the motor (5.2) for driving the mixing tool (5.1) is attached to the front end of the housing (5.3) is arranged. 3. Mixer (5) of a continuous mixing plant according to one of claims 1 to 2, characterized in that the housing (5.3) is designed as a hollow cylinder closed on one side, wherein the rear end of the housing (5.3) is open. 4. Mixer (5) of a continuous mixing plant according to one of claims 1 to 3, characterized in that the mixing tool (5.1) consists of a shaft on which elastic Mixing elements (5.1.1) are attached. 5. mixer (5) of a continuous mixing plant according to one of claims 1 to 4, characterized in that at least one mixing lement (5.1.1) with at least two spaced legs page 21 the shaft of the mixing tool (5.1) is connected, which through are connected to a web running parallel to the shaft. 6. mixer (5) of a continuous mixing plant according to claim 5, characterized in that the web is in contact with the in- inside of the mixer housing (5.3). 7. mixer (5) of a continuous mixing plant according to one of claims 1 to 6, characterized in that the inside of the mixer housing (5.3) over its entire length with one or several mixing elements (5.1.1) is in contact. 8. mixer (5) of a continuous mixing plant according to one of claims 1 to 7, characterized in that the mixing elements (5.1.1) against the inside of the horizontal mixer housing (5.3) are preloaded. 9. Mixer (5) of a continuous mixing plant according to one of claims 1 to 8, characterized in that the at least two legs of a mixing element (5.1.1) are radially offset from one another. which are attached to the shaft. 10. Mixer (5) of a continuous mixing plant according to one of claims 1 to 9, characterized in that the mixing elements (5.1.1) are made of a 0.5 mm - 1.5 mm thick spring steel sheet. forms are. page 22