DE102018002473B4 - Mixing device for fibres or chips and binders - Google Patents

Abstract

Mixing device for continuously mixing fibers or chips with a binding agent for the production of fiberboard or chipboard, wherein the mixing device has at least one mixing chamber (1) supported by a frame (15, 16, 17) with a loading opening (4), binding agent feed pipes (5) and a discharge opening (7) in the lower region of the mixing chamber and therein a plurality of mixing or conveying tools (3, 8, 9, 10) fastened to a rotatable mixer shaft (2), characterized in that the mixer shaft (2) has partially covered grooves (20) in which movable sliding blocks (21) are arranged, which can be connected to a mixing or conveying tool (3, 8, 9, 10).

Description

The invention relates to a mixing device for continuously mixing fibers with a binder for the production of fiberboard or chipboard, wherein the mixing device has at least one mixing chamber supported by a frame with a loading opening, binder feed pipes and a discharge opening in the lower region of the mixing chamber as well as several mixing or conveying tools attached to a rotatable mixer shaft.

Such mixing devices are also known as gluing mixers. The mixing chamber is usually cylindrical in shape as a drum, although this drum does not rotate but is stationary and only the mixer shaft with the mixing or conveying tools rotates.

The gluing of fibers or chips and consequently the mixing of fibers or chips with a binding agent or glue represents an essential process step in the production of fiberboard or chipboard. The quality of the boards produced, e.g. wood-based panels or in particular material boards made from the fibers of straw from annual plants, also depends significantly on the quality of the fibers and in particular on the homogeneous gluing of the fibers. In the following, the description of the invention focuses on the mixing of fibers and binding agents, but this should not exclude the use of chips instead of fibers.

It is generally known to mix fibers with a binding agent or glue in a so-called blowline and then glue them. However, the throughput is limited with this gluing technique. In practice, problems with so-called glue stains occasionally occur. In particular, the handling of isocyanate binding agents causes problems in blowline technology.

For this reason, the gluing of fibers in a gluing mixer has already been proposed. However, the results achieved in practice in the past with known gluing mixers were often unsatisfactory. Isocyanate binders, for example, harden at a certain temperature, which can already occur in the mixer.

A device for the continuous gluing of fibers, which is designed as a horizontally oriented gluing mixer in drum construction, is known for example from DE 24 38 818 or the parallel US 3 734 471 A known. In this embodiment, the mixing shaft is hollow and serves to supply glue. For this purpose, the mixer shaft is fitted with mixing tools which are provided with glue-throwing tubes protruding from the hollow part. The diameter of such a mixing container is approximately 600 mm, and a mixer shaft speed of 1500 revolutions per minute is suggested. This should achieve a throughput of 3 to 4 t of fibers per hour.

In practice, when gluing fibers with such devices, care has been taken to ensure that the fibers to be glued, which are set in a "rotating" movement by the mixing tools, have a predetermined speed or peripheral speed.

Furthermore, the DE 24 38 818 A1 a similar device for the continuous gluing of fibres.

From the EN 10 2009 057 916 B4 However, it is already known that a high centrifugal acceleration of the fibers in the area of the mixer's inner wall in the order of 10,000 to 30,000 m/sec ² can be selected with a correspondingly adjusted ratio of speed and diameter of the mixing chamber. This significantly improves the mixing ratio.

The mixing chamber has at least one loading opening for feeding the fibers and at least one unloading opening for discharging the fiber-binder mixture as well as several binder feed openings for feeding the binder. The invention according to the EN 10 2009 057 916 B4 proposes that several spike combs distributed over the circumference of the mixer shaft, each with several radially outward-oriented spikes, are provided as mixing tools, whereby the spike combs extend essentially parallel to the mixer axis and whereby two adjacent spike combs are arranged offset from one another in the axial direction by a predetermined amount. These spike combs or spikes take on a mixing function on the one hand and a conveying function on the other, because when the mixer shaft rotates with the mixing tools, the fibers are not only mixed with the binding agent, but the mixture is also transported in the conveying direction from the loading opening to the unloading opening perfectly and with high throughput. The axial offset of the individual spike combs achieves a spiral arrangement of the spikes, which improves the conveying effect. The individual spikes can also be referred to as mandrels or pins. It is also known to use shovels instead of these pins, particularly near the loading or unloading opening. like conveying tools. The spikes, pins, mandrels and blades are referred to below simply as mixing or conveying tools

However, this design, which has been successfully tested, also has disadvantages, which are primarily reflected in complicated maintenance work.

The high speeds and centrifugal accelerations are partly responsible for high temperatures in the mixing device. This creates the risk that glues and binding agents that harden quickly at higher temperatures, such as isocyanate, cause damage in the mixing chamber. Other binding agents that could be used would be methylene diphenyl isocyanates, urea formaldehydes, phenolic resins, etc. The mixing chamber then has to be cleaned at great expense during a production shutdown.

The inner wall of the mixing chamber and the tools are also often subject to high levels of wear, depending on the fiber and binding agent material. It is already known that wear-resistant materials can be used for the mixing chamber and the tools. However, repairs or replacement of these parts are relatively frequent, which also leads to production downtime.

Sometimes, for example when there is a change in production volume or when treating other fibers, it is desired to arrange the rotating tools, i.e. spikes, mandrels or shovel-like conveying tools, differently on the mixer shaft or to replace them with different ones or a different number. Nowadays, this involves removing the mixer shaft and equipping it with new tools.

The invention is based on the object of creating a mixing device that is easier to maintain and adapt to different process parameters.

The object is achieved with the features of claim 1 and in particular in that the mixer shaft has partially covered grooves in which movable sliding blocks are arranged, which can be connected to a mixing or conveying tool.

Up to now, agitator blades that can be moved in grooves have only been used in free-standing agitators that comprise a stirring bucket, a top cover, a stirring sleeve, an inner stirring shaft, a motor and a gear box, wherein the stirring bucket has a bucket-shaped structure whose cylindrical upper part is open and the stirring bucket is covered by the top cover, as shown for example in CN 1 07 754 679 A , known.

In this context, sliding blocks also include strips that can be inserted into the groove and have several receptacles for mixing or conveying tools.

Preferably, the mixing or conveying tools are also designed without a binding agent feed within the scope of this invention, i.e. the binding agent is not fed via the mixing or conveying tools themselves, but via separate (non-rotating) binding agent feed pipes which protrude, for example, in a radial direction by a predetermined amount through the mixing chamber casing into the interior of the mixing chamber. It is expedient if the feed pipes protruding into the mixing chamber are arranged offset in the longitudinal direction to the tools. This design enables the mixing or conveying tools to rotate easily at high speeds without colliding with the feed pipes, although the feed pipes can protrude into the area of the mixing or conveying tools.

The mixing device according to the invention is suitable for the gluing of fibers, e.g. for MDF production. Particularly preferably, fibers from annual plants, e.g. fibers from straw, e.g. rice straw, are also glued within the scope of the invention. In particular, for such fibers from annual plants, isocyanate or an isocyanate-containing binder is used as a binder. This binder is particularly useful for such annual plants because some annual plants are often provided with a wax layer. The high adhesive effect of isocyanate-containing binders nevertheless ensures perfect processing.

Surprisingly, the mixing device according to the invention is also particularly suitable for mixing fibers and in particular fibers with thermoplastic fibers, e.g. bicomponent fibers.

Mixing and conveying tools containing binding agent residues can therefore be replaced quickly and easily.

When dealing with different types of fiber and different throughputs, it is very beneficial if the mixing or conveying tools can be adjusted differently. This is done by moving individual sliding blocks or replacing strips. In addition, the mixing or conveying tools wear out over time due to friction with the minerals in and on the fibers. The effort required for such a change in setting or the replacement of tools would be enormous and would interrupt production.

Therefore, according to the invention, the mixer shaft is provided with partially covered grooves in which a sliding block or a bar that holds a tool can be moved. Partially covered grooves are therefore understood to mean grooves that have an opening width that allows one end of a tool to be inserted through. Partially covered also means that the groove widens radially inwards so that a sliding block adapted to the expanded cross-section cannot fall out when the mixer shaft rotates. The sliding block can therefore only be pushed into the groove and under the cover from one end of the mixer shaft or an extension hole. Open areas of the groove can also be advantageously protected against dirt deposits by means of covers.

Preferably, several parallel grooves run axially around the circumference of the mixer shaft.

This means that the mixing or conveying tools can be distributed as desired over the entire length of the mixer shaft. For example, depending on the type and length of the fiber, any number of conveying tools can be used in the area of the loading or unloading opening. The mixing tools, such as mandrels, can be accommodated in the middle axial length area of the mixer shaft in the required number. The distance between the tools can also be adjusted as desired.

It is advantageous if the mixing or conveying tools can be screwed into a threaded hole in the sliding block using a threaded bolt at their end.

This attachment is easy to manufacture and makes maintenance and tool replacement much easier. In addition, a rotatable adjustment option for the conveying tools is created.

It is particularly preferred if a lock nut and a washer that diverts the tightening forces to the side of the groove into the mixer shaft are arranged radially outside the groove.

It is particularly easy to attach a lock nut to a threaded bolt that is also screwed into the threaded hole in the sliding block, and tighten it against a thick washer. This avoids the forces of the lock nut on the groove covers, so that the groove is not damaged. The forces can be transferred to the areas of the mixer shaft to the side of the groove by using a thick washer. A self-locking washer can be used here, for example.

It is particularly advantageous if the mixing chamber comprises two half-shells made of bent sheet metal that can be connected.

The mixing chamber can then be divided and the mixer shaft with its tools and the inner peripheral surface of the mixing chamber are freely accessible, which considerably simplifies any maintenance.

Possibly in parallel, it is advantageous if the scaffolding is also divided into an upper and a lower scaffolding, and in particular if the half-shells are supported in an upper scaffolding part and a lower scaffolding part and, if appropriate, if the upper scaffolding part and the lower scaffolding part are connected to one another via a joint.

Then the upper and lower scaffolding parts, which can also be designed like a receiving tray for the half shells, can be opened up with the half shells.

If this opening is made possible, for example, by more than 90°, preferably even by 180°, one obtains the particular advantage that the half-shells of the mixing chamber can be removed from the upper part of the frame and/or the lower part of the frame.

In this case, even a half shell showing signs of wear can be completely replaced in order to shorten maintenance times.

Preferably, cooling channels with at least one coolant inlet and one coolant outlet are provided between the mixing chamber and the frame on the outer peripheral surface of the mixing chamber.

On the one hand, the mixing chamber can be easily cooled in this way, so that premature hardening of binding agents can be suppressed. The cleaning work in the mixing chamber is thus reduced.

On the other hand, when a half-shell is removed from the mixing device, the cooling channels can be removed at the same time and serviced or replaced.

Advantageously, the cooling channels are arranged in a meandering manner on the outer peripheral surface of the mixing chamber.

These can be, for example, two independent cooling circuits, one on each half shell. The cooling channels preferably run in a meandering shape, particularly in the conveying direction of the material, so that the heat absorption in the cooling liquid is distributed relatively evenly over the entire length of the mixing chamber.

Most preferably, a part of a cooling channel is formed by the outer peripheral surface of the mixing chamber.

The cooling liquid therefore has direct contact with the outer peripheral surface of the mixing chamber and the heat transfer value is further improved.

It is advantageous that a cooling channel is detachably attached to the outer peripheral surface of the mixing chamber. When a half-shell is replaced for maintenance purposes, the cooling channels can be easily removed and reused.

Preferably, the inner peripheral surface of the mixing chamber is provided with a low-wear armor plating.

An armored layer made of wear-resistant material ensures that the abrasive components in and around the fibers cause hardly any abrasion on the inner peripheral surface of the mixing chamber. At the very least, maintenance or replacement of the mixing chamber due to wear is significantly delayed.

It has proven to be advantageous if the inner peripheral surface of the mixing chamber is provided with tiles made of silicon carbide.

These tiles are very durable. But it is particularly worth mentioning that the tiles can be attached to a smooth sheet of metal (for example by gluing or welding) and then this sheet of metal can be bent to form a half-shell for the mixing chamber.

Alternatively, it is preferred if the inner peripheral surface of the mixing chamber is provided with a weld layer with a surface hardness >600 HV.

In this case too, the armoring is sufficiently effective. Such an armor layer is easy to apply. At least one weld layer is applied to the base shell made of weldable steel, which has a greater hardness than the base shell. The weld layer is provided, for example, in conjunction with a tungsten carbide layer. The weld layer can be applied in a spiral shape.

When applying the armor and bending a sheet into a half-shell, it is advantageous to ensure that the half-shells have been heat treated before installation.

This reduces the stresses in the mixing chamber and prevents deformation. Material properties such as toughness, microstructure, dimensional stability, residual stress and/or the hardness of the mixing chamber wall can be adjusted through heat treatment.

• 1 eine Mischvorrichtung der Erfindung in geschlossenem Zustand in einer perspektivischen Darstellung,
• 2 eine Explosionszeichnung einer Mischvorrichtung der Erfindung in einer perspektivischen Darstellung,
• 3 einen Ausschnitt aus der Mischerwelle der Erfindung in einer perspektivischen Darstellung
• 4 eine Mischkammer der Erfindung in einer perspektivischen Darstellung mit Kühlkanälen und
• 5 eine Draufsicht auf ein Mischsystem im Rahmen der Erfindung.

In the following, the invention is explained in more detail with reference to drawings showing exemplary embodiments.

• 1 a mixing device of the invention in closed state in a perspective view,
• 2 an exploded view of a mixing device of the invention in a perspective view,
• 3 a section of the mixer shaft of the invention in a perspective view
• 4 a mixing chamber of the invention in a perspective view with cooling channels and
• 5 a plan view of a mixing system within the scope of the invention.

In the 1 and 2 a mixing device 101 for continuously mixing fibers with a binding agent for the production of fiberboard is shown. The mixing device 101 has a substantially horizontally arranged, cylindrical mixing chamber 1 with a hollow cylindrical casing 6 and at least one mixer shaft 2 arranged to rotate in the mixing chamber 1, to which several mixing tools 3 are attached. The mixing chamber 1 has a loading opening 4, which in the exemplary embodiment is designed as a loading funnel. The fibers are introduced from above into the interior of the mixing chamber 1 via this loading funnel. The fibers are mixed with a binding agent via the mixer tools 3 attached to the rotating mixer shaft 2 and at the same time are conveyed through the mixer in the conveying direction from front to back. The binding agent is fed via several binding agent feed pipes 5, which are attached to the mixing chamber 1 and protrude through the mixing chamber casing 6 into the interior of the mixing chamber 1. In the embodiment shown, the binding agent is therefore not supplied via the mixer shaft or the mixing tools, but via the fixedly attached to the mixing chamber 1 or the jacket 6 of the mixing chamber 1, which are designed as feed nozzles. The mixing device also has a discharge opening 7, which is arranged at the end in the conveying direction. The mixture of fibers on the one hand and binding agents on the other hand is discharged or ejected via this discharge opening 7. The discharge opening 7 is provided in the lower area of the mixing chamber 1.

A drive (not shown) is connected to the mixer shaft 2 in a manner known per se. In the exemplary embodiment, the drive is arranged at the end or outlet side.

1 clarifies that a drive 34 is connected to the mixer shaft 2 in a manner known per se. In the embodiment, the drive is arranged at the end or outlet side. This should be easy to couple, because one can see a transport means 43 underneath the mixing device, which is suitable for moving the entire mixing device 101 away. This will be explained in more detail in the description of the 5 explained.

During operation of the mixing device according to the invention, the fibers are introduced into the mixing chamber 1 via the loading opening 4 and at the same time the binding agent, e.g. a glue such as isocyanate, is fed via the feed pipes 5. The fibers are transported along the longitudinal direction by means of the mixing tools 3 and are brought to the outer area via the centrifugal acceleration and consequently accelerated into the area of the mixer wall 6. The speed n of the mixer shaft and the diameter d of the mixing chamber are coordinated with one another in such a way that the (nominal) centrifugal acceleration a of the fibers in the area of the inner mixer wall is 15,000 to 30,000 m/sec ² . The diameter d is preferably 300 mm to 1500 mm and the speed n of the mixer shaft is preferably 1000 to 4000 rpm. Consequently, relatively small diameters and high speeds are used, so that high centrifugal accelerations are achieved. This ensures that the fibers are pressed well against the casing 6 or the inner wall of the mixer 1 and are compressed at the same time. This leads to increased friction and thus to better gluing behavior. At the same time, high throughputs of e.g. 5 t to 40 t per hour can be achieved.

The representation in 2 shows the structure of the mixing device 101 in a special way. It essentially consists of a lower frame part 17, which is usually detachably attached to the foundation, and an upper frame part 16, which here each have a shell-shaped sheet metal design with reinforcing bandages. The upper frame part 16 and the lower frame part 17 are connected to one another via a joint 18. This joint 18 enables the shell-shaped upper frame part 16 and the shell-shaped lower frame part 17 to be folded together to form a tubular casing 6, but can also be folded open by approximately 180° with the aid of a drive with gear 19.

This means that the mixing chamber 1, which is also divided into an upper half-shell 11 and a lower half-shell 12, can be inserted into the shell-shaped framework parts 16, 17, but can also be removed for quick maintenance. The half-shells 11, 12 are preferably bent from sheet metal and heat-treated. If the mixing chamber 1 is also opened in parts during the swiveling or folding process, the mixer shaft 2 with its mixing tools 3 is freely accessible for easy maintenance. In addition, the upper half-shell 11 or the lower half-shell 12 of the mixing chamber of the respective framework half can be removed and completely replaced if excessive wear occurs.

How 2 As can be seen, in the exemplary embodiment, several mixing tools 3 distributed over the circumference of the mixer shaft 2, each with a large number of spikes 8 oriented radially outwards, are provided as mixing tools 3. The mixing tools 3 extend along the longitudinal direction of the mixing chamber and thus parallel to the longitudinal axis of the mixer. Two adjacent mixing tools 3 are preferably arranged offset from one another by a predetermined amount in the axial direction or in the longitudinal direction. This configuration means that the ends of the individual spikes 8 are arranged in a helical manner in a plan view. This ensures that not only is the fibers mixed perfectly with the binder via the spikes 8, but that the mixture is also transported perfectly with a high throughput. In the exemplary embodiments, several feed pipes 5 are arranged in a row along the longitudinal direction of the mixer.

The binder feed pipes 5 protruding through the mixer wall 6 into the mixing chamber are arranged offset in the longitudinal direction to the spikes 8 of the mixing tools 3.

The 2 further shows that the area of the mixer shaft 2 associated with the loading opening 4 is designed to be free of spikes, with conveying tools 9 being attached to the mixer shaft 2 in this feed area. In the exemplary embodiment, these conveying tools are designed in the form of paddles as push tools or push paddles. They ensure that the fibers entering the mixing chamber 1 via the loading opening 4 are quickly accelerated and conveyed into the gluing area.

It can also be seen that the area of the mixer shaft 2 associated with the discharge opening 7 is partially formed with spikes. In addition, ejection tools 10 are attached to the mixer shaft 2 in this discharge area. These ejection tools 10 are also designed as paddle-shaped ejection paddles. They ensure rapid removal of the mixture of fibers and binding agent and consequently of the glued fibers via the discharge opening 7.

In an alternative embodiment not shown, the invention also includes embodiments in which the binding agent is supplied via the mixer shaft and the mixing tools, e.g. the spikes. In such a mixer with "internal gluing", the mixer shaft is designed as a hollow shaft and the spikes are also designed as binding agent supply pipes which are connected to the mixer shaft.

If glue feed pipes are used which extend essentially radially through the mixer casing 6 into the mixing chamber 1, it is possible for these glue pipes or their nozzles to be designed to be height-adjustable. This means that the immersion depth of the glue pipes in the radial direction into the interior of the mixing chamber can be adjusted.

3 shows clearly how the mixing and conveying tools 3, 8, 9, 10 are adjustably attached to the mixer shaft 2 in a maintenance-friendly manner. In this embodiment, the mixer shaft 2 has several T-grooves arranged in the longitudinal direction, i.e. grooves 20, which are partially covered. The shape of the groove 20 can vary within the scope of the invention and can also be dovetail-shaped, for example.

Sliding blocks 21 are slidably mounted within the groove 20 and are provided with a threaded hole. Each mixing and conveying tool 3, 8, 9, 10 has a threaded bolt 23 on a lower shaft that can be screwed into the sliding block 21. The mixing and conveying tool 3, 8, 9, 10 is fixed in place with the aid of a lock nut 24. A thick washer 25 with a larger diameter than that of the lock nut 24 helps to direct the forces beyond the groove cover into the mixer shaft 2.

4 shows the cooling of the mixing chamber 1 within the scope of this invention. The jacket of the mixer is preferably water-cooled. For this purpose, cooling channels made of semi-finished products 26 with at least one coolant inlet 28 and one coolant outlet 29 are attached to the outer surface of the mixing chamber. In this embodiment, the individual channel sections 27.1, 27.2 run parallel in the axial direction and are connected in a meandering manner via deflections 31.

Preferably, the semi-finished products are pipes, pipe sections or bent sheets that are glued, welded or screwed onto the outer circumference of the mixing chamber 1 using interposed seals. Then it is possible to form part of the channel wall 30 through the outer surface 14 of the mixing chamber 2 itself. This significantly improves the heat transfer. An example of a screw connection 35 of bent sheets 26 with the mixing chamber 1, which together with part of the surface 30 of the mixing chamber form a cooling channel 26, is shown in 4a shown. If the cooling channel 26 is detachably mounted on the mixing chamber 1, it can easily be serviced separately.

Just as the spikes or pins are designed as wear-resistant spikes or pins, the inner walls of the mixing chamber 1 can also be designed to be wear-resistant, e.g. armored with abrasion-resistant coatings. Examples of this could be a build-up weld 33 with a surface hardness >600 HV or tiles made of silicon carbide 32.

5 finally shows an entire mixing system 100, for example for a large rice straw plant. In such a plant, the mixing devices are particularly at risk because the fibers to be mixed with binding agents are still very abrasive. In order to meet the maintenance requirements, working positions 41.1, 41.2, 41.3, 41.4 are provided for the mixing devices 101 as well as two maintenance positions 42.1, 42.2 in a separate maintenance room. In both positions, the upper frame part 16 and the upper half-shell 11 are shown unfolded by 180°.

Transport means capable of transporting a mixing device 101 move between the individual work and maintenance positions. A mixing device 101a that is about to be transported is shown in the closed state.

The preferred solution shown in the embodiment includes transport carriages that can be moved on rails 44. It is intended that a lifting device 45 is present (visible in 1 ), which can lift the mixing device 101 detached from the foundation so that a transport vehicle can drive underneath. The mixing device is then placed in its entirety on the transport means 43 and, for example, from a working position 41.1, 41.2, 41.3, 41.4 to a maintenance position 42.1, 42.2. The transport means can move lengthways and crossways, as is offered, for example, by Strothmann Machines and Handlingssysteme GmbH with its round rail system.

In the maintenance position, the mixing device can then be conveniently opened and cleaned without interrupting the production process. If the mixing device is connected to a drive 34, the mixer shaft 2 can be rebalanced.

List of reference symbols

1

Mixing chamber

2

Mixer shaft

3

Mixing tool

4

Loading opening

5

Binder feed pipes

6

Coat

7

Discharge opening

8th

Spines

9

Conveying tool

10

Ejection tool

11

Upper half shell

12

Lower half shell

13

Inner peripheral surface of the mixing chamber

14

Outer peripheral surface of the mixing chamber

15

framework

16

Upper scaffolding part

17

Lower scaffolding part

18

joint

19

Drive with gearbox

20

Groove

21

Scenic stone

22

Threaded hole of the sliding block

23

Threaded bolt

24

Lock nut

25

Washer

26

Cooling channel made of semi-finished products

27.1, 27.2

Canal section

28

Coolant inlet

29

Coolant outlet

30

Part of the cooling channel

31

Redirection

32

Tiles

33

Weld layer

34

Drive of the mixer shaft

35

Screw connection

36

Curved sheet metal

41.1, 41.2

Working position

42

Maintenance position

43

Mode of Transport

44

rail

45

Lifting or lowering device

100

Mixing system

101

Mixing device

Claims (15)

Mixing device for continuously mixing fibers or chips with a binding agent for the production of fiberboard or chipboard, wherein the mixing device has at least one mixing chamber (1) supported by a frame (15, 16, 17) with a loading opening (4), binding agent feed pipes (5) and a discharge opening (7) in the lower region of the mixing chamber and therein a plurality of mixing or conveying tools (3, 8, 9, 10) fastened to a rotatable mixer shaft (2), characterized in that the mixer shaft (2) has partially covered grooves (20) in which movable sliding blocks (21) are arranged, which can be connected to a mixing or conveying tool (3, 8, 9, 10). Mixing device according to Claim 1 , characterized in that several parallel grooves (20) run axially on the circumference of the mixer shaft (2). Mixing device according to Claim 1 or 2 , characterized in that the mixing or conveying tools (3, 8, 9, 10) are provided with a threaded bolt (23), the end of which can be screwed into a threaded bore (22) of a sliding block (21). Mixing device according to one of the Claims 1 until 3 , characterized in that a lock nut (24) and a washer (25) which diverts the tightening forces laterally of the groove into the mixer shaft (2) are arranged radially outside the groove (20). Mixing device according to Claim 1 until 4 , characterized in that the mixing chamber (1) comprises two half-shells (11, 12) bent from sheet metal and connectable. Mixing device according to Claim 5 , characterized in that the half-shells (11, 12) are supported in an upper frame part (16) and a lower frame part (17). Mixing device according to Claim 6 , characterized in that the upper frame part (16) and the lower frame part (17) are connected to one another via a joint (18). Mixing device according to one of the Claims 6 until 7 , characterized in that the respectively associated half-shell (11, 12) is detachably fastened and removable in the upper frame part (16) and/or the lower frame part (17). Mixing device according to one of the Claims 1 until 8th , characterized in that cooling channels (26) with at least one coolant inlet (28) and one coolant outlet (29) are provided between the mixing chamber (1) and the frame (15) on the outer peripheral surface of the mixing chamber (1). Mixing device according to Claim 9 , characterized in that the cooling channels (26) are arranged in a meandering shape on the outer peripheral surface of the mixing chamber (1). Mixing device according to one of the Claims 9 until 10 , characterized in that a part of a cooling channel (26) is formed by the outer peripheral surface of the mixing chamber (1). Mixing device according to one of the Claims 1 until 11 , characterized in that the inner peripheral surface of the mixing chamber (1) is provided with a low-wear armoring. Mixing device according to Claim 12 , characterized in that the inner peripheral surface of the mixing chamber (1) is provided with tiles (32) made of silicon carbide. Mixing device according to Claim 12 , characterized in that the inner peripheral surface of the mixing chamber (1) is provided with a weld layer (33) with a surface hardness > 600 HV. Mixing device according to one of the Claims 5 until 14 , characterized in that the half-shells (11, 12) were subjected to heat treatment before installation.