EP3581264B1 - Device for manufacturing a flowable medium - Google Patents

Description

The invention relates to a device for producing a flowable mortar mass, in particular a fine-grained mortar mass, such as a filler.

In the case of fine-grained mortar masses, such as fillers, which are used to fill holes and cracks or to completely fill plasterboard, the mortar mass is mixed by so-called soaking. Dry mortar is sprinkled on top of water, which soaks up the water, and the mortar mass is then mixed. Particularly with fine-grained mortar masses, nodules and smaller lumps form, which make continuous mixing and conveying difficult. In practice, these fine-grain mortar mixtures are therefore first mixed in a separate mixer and, after a longer mixing time, fed to a pump for delivery. Thus, only batch operation is possible with the prior art.

From the DE 197 54 969 A1 a device is known with which thin-bodied foam pulp or a thin-bodied, foamy mortar mass can be continuously produced in a nodule-free, homogeneous consistency and with which a high conveying capacity is achieved. The device comprises a main mixer for mixing dry mortar with water and an eccentric screw pump arranged downstream of the main mixer for conveying the premixed mortar mass to a post-mixer. The post-mixer is arranged at an outlet of the eccentric screw pump and has a vane rotor which is arranged in the center of a housing. Water is fed into the housing, which is mixed with the mortar mass by the vane rotor in order to obtain a thin-flowing mortar mass. Smaller ones However, nodules or lumps are hardly detected by the vane rotor, since they can avoid the vane rotor.

Out EP 1 721 717 B1 a device for producing a flowable mortar mass, in particular a fine-grained mortar mass, is known. The mixer rotor of the post-mixer is attached eccentrically to a conveyor rotor of an eccentric screw pump. The mixing rotor is essentially rod-shaped and serves to grind lumps or nodules contained in the mortar mass between an active surface of the mixing rotor and an opposing surface, in particular an inner surface, of a mixing tube.

From the DE 10 2009 047 717 A1 An eccentric screw pump is known for the delivery of fluids, in particular liquid mortar, with a stator consisting of an elastomer, a pump cavity shaped like a two or more coarse thread, and with a motor-driven stator that extends through the pump cavity with radial eccentricity and is driven by a motor High helix shaped rotor. At the end of the stator on the pressure side, the pump cavity opens into a mixing chamber in which a mixing element connected to the rotor in a rotationally fixed manner engages. The mixing element is equipped with turbine blades, forming a turbine insert, which are directed against the direction of flow of the fluid for a given direction of rotation of the rotor. The inside diameter of the mixing chamber with the mixing element is larger than the pump cavity. The mixing element is spaced from the inner wall of the mixing chamber. With the help of this post-mixer of this well-known eccentric screw pump, an improved mixing quality and an increased proportion of air voids is achieved. The pumped fluid is effectively mixed up and the proportion of air voids is increased, which improves the productivity and workability of mortar.

It is the object of the invention to develop a device of the type mentioned at the beginning in such a way that the mixing effect is preferably further improved.

This object is achieved in particular by a device with the features of claim 1. Advantageous designs and developments emerge in particular from the dependent claims.

In one embodiment, a device for producing a flowable mass, in particular a fine-grain mortar mass such as a filler, comprises a main mixer for mixing dry mortar with water and a rotating displacement pump, in particular an eccentric screw pump, for conveying the premixed mass to a post-mixer. The rotating positive displacement pump has a delivery rotor which can be rotated in a stator, in particular an eccentric worm rotor, with a delivery thread. The post-mixer has a mixing rotor with an active surface, in particular arranged on the outer surface of the mixing rotor, and a mixing tube with a counter surface, in particular arranged on the inner surface of the mixing pipe. The mixing rotor can be driven via the conveying rotor in such a way that the active surface of the mixing rotor can be rotated about a central axis of the mixing tube along the counter surface.

In one embodiment of the invention, the mixing rotor is designed so that the conveying direction or the conveying direction or the conveyed material flow of the mixing rotor of the post-mixer is at least partially or altogether opposite to the conveying direction or conveying direction or conveyed material flow of the conveying thread of the conveying rotor. In this way, turbulence is generated in the material flow, which improves the mixing.

In one embodiment of the invention, the mixing rotor has a mixing thread (or: a mixing helix) which is designed to run in opposite directions to a direction of rotation (also: direction of rotation) of the conveying thread. If the conveying thread of the conveying rotor is thus designed as a right-hand thread (also: right-hand thread), then the mixing thread of the mixing rotor is designed accordingly as a left-hand thread (also: left-hand thread). In the opposite case, if the conveying thread of the conveying rotor is thus designed as a left-hand thread (also: left-hand thread), the mixing thread of the mixing rotor is corresponding designed as a right-hand thread (also: right-hand thread). As a result, an opposite conveying effect or conveying direction or conveying direction or material flow of the mixing rotor compared to the conveying thread is at least partially achieved.

Basically, the device is designed to guide the mortar mass in the remixer between an active surface and a counter surface in such a way that it is conveyed in the conveying direction along the counter surface and the active surface is moved along the counter surface, the active surface in particular rotating or revolving carries out a central axis of the post-mixer along the counter surface. It has now been found that the grinding of lumps between the active surface and the opposing surface can be improved if the mixing rotor itself is provided with a mixing thread which is designed in the opposite direction to the conveying thread of the conveying rotor. The mixing thread thus generates a material flow movement which is directed against the conveying direction of the conveying thread. In this way, a strong turbulence is generated in the material flow, which is effectively moving in the conveying direction.

As a result of the turbulence mentioned, lumps or nodules of the conveyed mortar mass reach the area between the effective surface and the opposing surface. There they are exposed to comparatively high pressure, friction and shear forces and are crushed and ground between the effective surface and the counter surface, so that the mortar mass is effectively homogenized. As a result of the rotating or revolving movement of the active surface, the mortar mass is continuously pressed and rubbed, so that continuous production and delivery of an essentially homogeneous mortar mass is ensured.

In one embodiment, the active surface is formed by the outer surface of the circumferential mixing thread. In particular in the case of opposing surfaces with cylindrical symmetry, this means that the contact area between the effective and opposing surface is essentially the Has the shape of a helix. This structural design of the active surface further favors the conveyance of the material in the direction of the comminution area between the active and counter surface.

As a result of the rotational or revolving movement of the active surface, the mortar mass is pressed and rubbed, so that production and delivery of an essentially homogeneous mortar mass is ensured. In this way, both thin and viscous mortar masses can be effectively homogenized without the need for additional measures to change the consistency, for example the supply of water or compressed air. Since the mixing thread itself moves material in the opposite direction to the conveying direction, more mortar mass is effectively pressed into the area between the active and opposing surface, thus improving the homogenization of the mass flow.

Furthermore, the stator of the rotating displacement pump, in particular a delivery pipe through which the mortar mass is delivered, has a larger internal diameter than the fluidically downstream mixing pipe. In this way, a sufficient conveying effect in the conveying direction is ensured. In addition, the mass flow condenses in the area of the remixer, so that the lumps can possibly already be ground up by internal friction.

In one embodiment, the mixing rotor has a circular, oval or elliptical cross section.

In one embodiment, the mixing rotor of the post-mixer is arranged on an end region of the feed rotor assigned to the post-mixer, in particular formed in one piece with the feed rotor, or connected to the feed rotor in a materially bonded manner by welding. Such, in particular one-piece designs have the advantage of increased stability.

Alternatively, the mixing rotor is connected to the conveyor rotor by means of fastening means, in particular by means of a screw connection. The mixing rotor thus forms an extension of the delivery or screw rotor of the rotating displacement pump. Detachable connections allow in particular in an advantageous manner the exchange of mixing rotors depending on the need or application, in particular depending on the viscosity of the flowable mass to be produced.

In one embodiment, the active surface of the rotor lies essentially close to the counter surface of the mixing tube or it is at least slightly pressed against the counter surface, the active surface and / or the counter surface being made of an elastic material such as a synthetic or natural rubber comprising, wear-resistant rubber are. The use of rubber improves the adhesion and friction of the mortar mass on the respective surface made of rubber. In addition, rubber is sufficiently resilient so that the mortar mass can pass between the surfaces and be squeezed to a large extent.

According to an advantageous embodiment, the opposing surface is elastic and the active surface is comparatively inelastic or rigid, so that only the opposing surface yields elastically when the mortar mass is passed through and pressed. Due to the elastic counter surface and the inelastic or rigid active surface, the pressure on the mortar mass is noticeably increased with simultaneous squeezing of the mortar mass between the surfaces, so that even smaller lumps or nodules are crushed.

According to another advantageous embodiment, the elastic and inelastic behavior of the surfaces is reversed, the active surface being elastic and the counter surface being comparatively inelastic or rigid, so that only the active surface yields elastically when the mortar mass is passed through and pressed. In this version, too, the mortar mass is squeezed between the surfaces and at the same time subjected to increased pressure.

In a preferred embodiment, the active surface of the mixing rotor and the counter surface of the mixing tube are each formed from materials with different elastic properties, an elastic material such as rubber and a comparatively inelastic material such as metal, preferably steel, being selected as a pair of materials. Such a choice of material exerts increased pressure on the mortar mass and at the same time achieves sufficient elastic resilience of the surface made of rubber.

According to one possible embodiment, the counter surface of the mixing tube is made of rubber, the mixing tube having an outer tube and a rubber insert which is attached to the inside of the outer tube and whose inner surface forms the counter surface, and the effective surface of the rotor is in particular made of metal, preferably made of Formed steel. By using a rubber insert and arranging it on the outer tube, an elastically flexible and at the same time hard-wearing counter surface is created.

In the embodiments described above, with regard to the pressure, friction and shear forces acting on the mortar mass, it is sufficient if the active surface is moved tightly or essentially without any gaps along the opposing surface.

Alternatively, both the active surface and the opposing surface can be elastic, in which case it is particularly advantageous if the active surface is additionally pressed against the opposing surface in order to exert or maintain an increased pressure on the mortar mass.

In particular in designs which have mixing rotors with an elliptical or oval cross-section, a gap is provided in a circumferential section between the mixing rotor and the mixing tube. In other words, the mixing rotor does not fully rest on the mixing tube.

In one embodiment, the mixing tube of the post-mixer is formed in one piece with a delivery tube of the rotating positive displacement pump, the outer tube and the Rubber insert of the mixing tube are each formed in one piece with an outer tube and a rubber insert of the conveyor tube. The remixer and the eccentric screw pump are combined by these structural measures to form a compact and inexpensive to manufacture unit.

According to an alternative embodiment, the mixing tube of the post-mixer and a delivery tube of the eccentric screw pump are designed as separate parts and connected to one another via fastening means, such as a flange or a clamping flange, the flange having a radially inwardly protruding, ring-shaped collar between the Rubber insert of the mixing tube and a rubber insert of the conveyor pipe is arranged and rests on it in a sealing manner. By designing the mixing tube and the delivery tube as separate parts, the mixing tube can be used as required and removed again, for example for cleaning. The sealing collar of the flange prevents mortar from penetrating between the two rubber parts.

The delivery pipe and the mixing pipe are preferably arranged coaxially to one another. In an arrangement of this type, it is provided in an embodiment to brace the fastening means, in particular the flange or clamping flange, in a non-positive manner between the delivery pipe and the mixing pipe via axially acting clamping means, in particular tie rods. The axial bracing is used for increased stability, so that the forces that arise when conveying highly viscous masses can also be compensated.

Preferably, the rubber insert of the mixing tube is materially connected to the outer tube of the mixing tube by vulcanization, as a result of which the rubber insert is firmly seated on the outer tube. As an alternative or in addition, the rubber insert of the delivery pipe is preferably materially connected to the delivery pipe of the positive displacement pump by vulcanization.

The pitch of the mixing thread or the mixing helix can in embodiments be axially constant or also vary axially. Instead of a mixed thread you can In all embodiments, individual mixing thread sections and / or individual mixing rotor blades or mixing rotor blades spaced from one another can also be provided on the mixing rotor, which also have a conveying direction opposite to the conveying thread and whose outer surfaces form individual active surfaces of the mixing rotor in the post-mixer.

The invention is explained in more detail below with regard to further features and advantages using exemplary embodiments and with reference to the accompanying drawings.

FIG 1

eine schematische Darstellung einer erfindungsgemäßen Vorrichtung gemäß einer ersten Ausführungsform in Schnittansicht,

FIG 2

eine schematische Darstellung der erfindungsgemäßen Vorrichtung gemäß einer zweiten Ausführungsform in Schnittansicht, und

FIG 3

eine schematische Darstellung der erfindungsgemäßen Vorrichtung gemäß einer dritten Ausführungsform in Schnittansicht.

Here show:

FIG 1

a schematic representation of a device according to the invention according to a first embodiment in sectional view,

FIG 2

a schematic representation of the device according to the invention according to a second embodiment in sectional view, and

FIG 3

a schematic representation of the device according to the invention according to a third embodiment in sectional view.

In FIG 1 is a schematic representation of a device according to a first embodiment shown in sectional view. The apparatus comprises a main mixer for mixing dry mortar and water (not shown). The main mixer is followed by a rotating displacement pump 8 designed as an eccentric screw pump in order to convey the premixed mortar mass, in particular a fine-grained mortar mass such as a filler, in the conveying direction F to a post mixer 1. The positive displacement pump 8 has a delivery pipe 10 which comprises an outer pipe 11 and a rubber insert 12 which is arranged on the inside of the outer pipe 11. The rubber insert 12 forms a worm gear-shaped conveying channel 13 through which the mortar mass is pumped to the post-mixer 1 by means of a conveying rotor 9 rotating in the conveying channel 13, which is formed by an eccentric worm rotor.

The post-mixer 1 is arranged at an outlet 14 of the rotating displacement pump 8 and comprises a mixing tube 4 and a mixing rotor 2, which is arranged coaxially to the delivery rotor 9. The mixing rotor 2 is arranged on an end region 25 of the conveying rotor 9 assigned to the post-mixer 1 and is fastened to it by means of a screw connection not shown in detail.

In an alternative embodiment, the mixing rotor 2 and the conveying rotor 8 are designed in one piece.

The mixing rotor 2 of the post-mixer 1 extends, starting from the conveying rotor 9, in the conveying direction F or parallel to a central axis A of the mixing tube 4 over the length L of the mixing tube 4.

The mixing tube 4 comprises an outer tube 6 and a rubber insert 7, which is attached to the inside of the outer tube 6 and is materially connected to the outer tube 6 by vulcanization. The mixing rotor 2 of the post-mixer 1 and the conveyor or screw rotor 9 are made of metal, expediently made of steel. The rubber insert 7 and the outer tube 6 of the mixing tube 4 are each formed in one piece with the rubber insert 12 and the outer tube 11 of the delivery tube 10, so that the post-mixer 1 forms an integral part of the positive displacement pump 8.

The mixing rotor 2 has a helical mixing thread 16, the outer surface of which forms an active surface 3 which rests essentially tightly, i.e. essentially without a gap, on the cylindrical inner surface of the rubber insert 7. The inner surface of the rubber insert 7 forms an elastic counter-surface 5 that interacts with the inelastic or rigid active surface 3 of the mixing rotor 2. In addition, the rotor 2 can be pressed with its active surface 3 against the counter-surface 5 of the mixing tube 4.

The mixing rotor 2 is driven by the rotating displacement pump 8, so that its active surface 3 rotates around the central axis A along the counter surface 5 in accordance with the rotational movement of the conveyor or screw rotor 9. The mortar mass, which is conveyed along the opposite surface 5 of the mixing tube 4 in the conveying direction F, is guided, pressed and rubbed between the inelastic or rigid active surface 3 of the mixing rotor 2 and the elastic opposite surface 5 by the rotational or revolving movement of the mixing rotor 2, wherein the elastic mating surface 5 yields elastically when the mortar mass is passed through and pressed.

The mixing thread 16 is formed in the opposite direction to a conveying thread 17 of the conveying rotor, i. H. Mixing thread 16 and conveying thread 17 are shaped opposite to one another with regard to their direction of rotation or their direction of rotation. In the embodiment shown as an example, the conveying thread 17 is right-handed and the mixing thread 16 is left-handed. Since the conveying rotor 9 and the mixing rotor 2 are connected to one another in a rotationally fixed manner, they rotate at the same rotational speed in the conveying mode. The opposing formation of the threads causes opposing conveying movements in the conveying operation. Due to the dimensioning of the conveyor rotor 9 in comparison to the mixing rotor 2, the resulting mass flow is directed in the conveying direction F, but strongly swirled, ie. H. turbulent. Lumps can already be crushed by the increased internal friction or between the active and opposing surfaces 3, 5.

The rubber insert 7 and the rubber insert 12 are formed from a wear-resistant elastomer made from synthetic or natural rubber, for example NR and / or SBR.

In FIG 2 is an alternative embodiment of the device of FIG FIG 1 shown in sectional view. The mixing tube 4 of the post-mixer 1 and the delivery tube 10 of the rotating positive displacement pump 8 are designed as separate parts and are connected to one another via an annular flange 15. The flange 15 has a radially inwardly projecting, annular collar 19 which is arranged between the rubber insert 7 of the mixing tube 4 and the rubber insert 12 of the conveying tube 10 and rests against it in a sealing manner. The collar 19 ends approximately flush with the rubber insert 7 and the rubber insert 12 and thus forms a continuous transition from the rubber insert 12 to the rubber insert 7.

For the rest, reference is made to the statements made with reference to FIG 1 referenced.

In FIG 3 is a schematic representation of a further embodiment of the device shown in sectional view. The mixing tube 4 of the post mixer 1 and the Delivery pipe 10 of the rotating positive displacement pump 8 are - as in the embodiment of FIG FIG 2 - Separate components that are connected to one another via a clamping flange 18. The clamping flange 18 likewise has an annular collar 19 which projects radially inward and which lies in a sealing manner between the rubber insert 7 of the mixing tube 4 and the rubber insert 12 of the conveying tube 10. In addition, the clamping flange 18 has two diametrically outwardly projecting holding elements 20 to which tension rods 21 are attached. The tie rods 21 are each supported at one end of the conveying pipe 10 or on one end of the mixing pipe 4 via holding elements 22. Axial forces can be exerted along the tension rods 21 via screws 23 and thus the components fastened to them can be braced axially to one another in the axial direction, that is to say in the direction of the central longitudinal axis A.

For the rest, reference is made to the statements made with reference to FIG 1 referenced.

In the exemplary embodiments of FIGS. 1 to 3 the active surface 3 is each formed from an inelastic material, such as a metal, in particular steel. The counter surface 5 is formed from a relatively elastic material such as rubber.

As an alternative to this, the opposing surface 5 can be formed, for example, from a metal and the active surface 3 from a relatively elastic material, such as rubber. For this purpose, the mixing rotor 2 with the mixing thread 16 can be provided with a rubber coating, for example. Alternatively, both the active surface 3 of the mixing rotor 2 and the counter surface 5 of the mixing tube 4 can be designed to be elastic, the mixing tube 4 having the rubber insert 7 and the mixing rotor 2 additionally being provided with a rubber coating.

The mixing thread or the mixing helix can have a constant or a varying pitch.

Instead of a continuous mixed thread, individual mixed thread sections and / or individual ones from one another can also be used in non-illustrated embodiments spaced mixing rotor blades or mixing rotor blades can be provided on the mixing rotor, which likewise have a conveying direction opposite to the conveying thread and the outer surfaces of which form individual active surfaces of the mixing rotor in the post-mixer.

List of reference symbols

1

Remixer

2

Mixing rotor

3

Effective area

4th

Mixing tube

5

Counter surface

6th

Outer tube

7th

Rubber insert

8th

Positive displacement pump

9

Conveyor rotor

10

Delivery pipe

11

Outer pipe (delivery pipe)

12th

Rubber insert

13th

Conveyor channel

14th

Outlet

15th

flange

16

Mixed thread

17th

Conveying thread

18th

Clamping flange

19th

collar

20th

Fastener

21

Tie rods

22nd

Retaining element

23

screw

25th

End area

A.

Central axis

F.

Conveying direction

L.

length

Claims (10)

1. Device for producing a flowable mass, in particular a fine-grained mortar mass such as a filler, comprising a main mixer for mixing dry mortar with water, a secondary mixer (1), and a rotating displacement pump (8), in particular an eccentric screw pump, for conveying the premixed mass to the secondary mixer (1), the rotating displacement pump (8) having a conveying rotor (9), in particular an eccentric screw rotor, which can be rotated in a stator, in particular in a conveying pipe (10), and comprises a conveying thread (17), and the secondary mixer (1) having a mixing rotor (2) which comprises an active surface (3) arranged in particular on the outer surface of the mixing rotor (2), and having a mixing pipe (4) which comprises a counter surface (5) arranged in particular on the inner surface of the mixing pipe (4), it being possible to drive the mixing rotor (2) via the conveying rotor (9) in such a way that the active surface (3) of the mixing rotor (2) can be rotated along the counter surface (5) about a central axis (A) of the mixing pipe (4), the mixing rotor (2) being designed such that the conveying direction of the mixing rotor of the secondary mixer is at least partially opposite to the conveying direction of the conveying thread of the conveying rotor, as a result of which in particular turbulence is generated in the mass, and/or the mixing rotor (2) having a mixing thread (16) or a mixing helix or mixing rotor blades or vanes which is/are designed to rotate in the opposite direction to that of the conveying thread (17), characterized in that the stator, in particular the conveying pipe (10), of the rotating displacement pump (8) has a larger internal diameter than the mixing pipe (4) arranged fluidically downstream.
2. Device according to claim 1, wherein the mixing rotor (2) has a circular, oval or elliptical cross section.
3. Device according to either of the preceding claims, wherein the mixing rotor (2) of the secondary mixer (1) is arranged on an end region (25) of the conveying rotor (9) that is associated with the secondary mixer (1), in particular is integral with the conveying rotor (9) or is connected to the conveying rotor (9) by welding or via fastening means, in particular by means of a screw connection.
4. Device according to any of the preceding claims, wherein the active surface (3) of the mixing rotor (2) lies substantially tightly against the counter surface (5) of the mixing pipe (4) or is at least slightly pressed against the counter surface (5), wherein the active surface (3) and/or the counter surface (5) are made from an elastic material, such as a wear-resistant rubber made from synthetic or natural rubber, and/or the active surface (3) of the mixing rotor (2) and the counter surface (5) of the mixing pipe (4) are each made from materials having different elastic properties, wherein an elastic material such as rubber and a comparatively inelastic material such as metal, preferably steel, are selected as the material pair.
5. Device according to any of the preceding claims, wherein the counter surface (5) of the mixing pipe (4) is made from a rubber, wherein the mixing pipe (4) has an outer pipe (6) and a rubber insert (7) which is attached to the inside of the outer pipe (6) and the inner surface of which forms the counter surface (5).
6. Device according to claim 5, wherein the mixing pipe (4) of the secondary mixer (1) is integral with a conveying pipe (10) of the displacement pump (8), wherein the outer pipe (6) and the rubber insert (7) of the mixing pipe (4) are respectively integral with an outer pipe (11) and a rubber insert (12) of the conveying pipe (10).
7. Device according to claim 5, wherein the mixing pipe (4) of the secondary mixer (1) and a conveying pipe (10) of the displacement pump (8) are designed as separate parts and are connected to one another via fastening means such as a flange (15) or clamping flange (18), wherein the flange (15) has an annular collar (19) which protrudes radially inwards, is arranged between the rubber insert (7) of the mixing pipe (4) and a rubber insert (12) of the conveying pipe (10) and rests against said inserts in a sealing manner.
8. Device according to claim 7, wherein the conveying pipe (10) and the mixing pipe (2) are arranged coaxially with respect to one another and the fastening means are frictionally braced between the conveying pipe (10) and the mixing pipe (2) via axially acting tension means, in particular tension rods (21).
9. Device according to any of claims 6 to 8, wherein the rubber insert (7) of the mixing pipe (4) is integrally bonded with the outer pipe (6) of the mixing pipe (4) by means of vulcanization and/or the rubber insert of the conveying pipe (10) is integrally bonded with the conveying pipe (10) of the displacement pump by means of vulcanization.
10. Device according to any of the preceding claims, comprising a mixing thread or a mixing helix, the mixing thread or the mixing helix having a constant or a varying pitch.

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