EP1470856B1 - Stirrer for mixing, homogenising and dispersing - Google Patents

Abstract

A stirrer for use in the purification of liquids comprises a rotating stirrer head (2) carrying paddles (4). This is mounted in a bearing (3) and has a coupling (5) for contactless-, inductive- or magnetic drive of the head. The drive side coupling components (6) are mounted in a split case (8) A bolt (15) passing centrally through the bearing and fastens it to the split case to prevent a gap forming due to it moving upwards. An independent claim is included for mounting a stirrer as described above on a tank.

Description

The invention relates to a stirrer for substance combining of fluid phases, consisting of a rotatably mounted by means of a bearing stirrer head with stirring, and a clutch for non-contact, inductive or magnetic, drive the stirrer head and a, for example, in a container, fixed containment shell for receiving the drive-side coupling part, wherein means for securing the stirrer head are provided before axial lifting.

Such a stirrer is known from US Pat. No. 4,993,841. When the drive motor is reversed in polarity, the magnetic force prevailing between the stirrer and the drive housing can be overcome and the stirrer can lift off through the axial component of the flow forces. Such an event endangers the entire batch in the container.

In order to avoid such malfunctions, DE 201 14 076 U shows a homogenizer which, in contrast to US Pat. No. 4,993,841, also has means for securing the stirrer head to axial lifting. In this construction, however, disadvantageous new cavities and contact surfaces, between which microorganisms can settle.

Other stirrers are known from the specifications GB-A-2 185 862, US-A-5 393 142 and US-A-6 065 865.

Finally, from DE 42 32 936 C2, a stirrer for stirring sterile liquids known. The stirrer head described is mounted floating on a pin attached to the containment shell. This has the disadvantage that only stirring tools can be provided on the stirrer head, which either cause a radial outflow of the liquid to be stirred or effect an axial flow component of the liquid upwards, so that the stirrer head is pressed by a hydraulic axial force towards the split pot. If the stirrer were operated in axial flow tools opposite to the prescribed direction of rotation, the stirrer head would lift off the containment shell. This however, impacting the stirrer on the container wall could result in damage and failure of the agitator.

Another disadvantage is that in known stirrers with stirrers for generating an axial flow only one direction of rotation can be realized. As a result, the range of use of stirrers with stirring tool for generating an axial flow is limited. It can only be generated a flow profile, which is directed away from the container bottom, so that the stirrer head is pressed in the direction of the split pot.

The known from DE 42 32 935 C2 stirrer, however, is secured against axial lifting by means of a screw. A disadvantage of the known stirrer is that the fuse is provided in the product space. This is a source of infection which can lead to considerable problems, in particular in the pharmaceutical or food-technical field of application.

The invention is therefore based on the object to propose a stirrer, which is particularly suitable for use in the pharmaceutical industry and the food industry.

This object is achieved in that the stirrer head is secured by the Spalttopfunterseite ago from axial lifting, as a means for securing the stirrer head, a screw is provided, which is screwed from the Spalttopfunterseite ago, for example, provided in a pin internal thread. The stirrer head is fixed almost axially. The means for securing the stirrer head take on the axially upward, acting on the stirrer head axial force. Of course, the backup of the stirrer head before axial lifting can be designed so that the stirrer head is axially displaceable in a certain range. This certain clearance may be necessary to allow adequate lubrication of the bearing and compensation for thermal expansion.

The inventive design of the stirrer, it is possible to operate even a stirrer head with stirring tool for generating an axial flow in both directions of rotation. This considerably expands the process engineering field of application. Furthermore, it is possible to use the stirrer according to the invention even with increased safety requirements, for example when working in potentially explosive atmospheres.

The fact that the fuse is outside the product space, ie without product contact, the probability of contamination or contamination of the product is significantly reduced. Another great advantage of the embodiment of the invention is that the fuse can be controlled from the outside.

According to an advantageous embodiment of the invention it is provided that the stirrer head, the bearing, the containment shell and the means for securing the stirrer head are designed as a structural unit. This makes it possible to introduce the preassembled unit in the container and to fix the outer side of the split pot from the outside and secure. This procedure is particularly advantageous since the bearing made mostly of ceramic can be damaged in the conventional assembly, in which the stirrer head with bearing bush is placed on a bearing sleeve attached to the containment shell. Since the stirrer head in the stirrer according to the invention is part of a structural unit, it no longer has to be individually applied in the container. Thus, the bearings are considerably spared during installation.

It is particularly useful if the bearing is arranged above the gap pot and in particular is formed as a combination of axial and radial bearings. Since the stirrer head can be operated in both directions, it is necessary that the axial forces of the stirrer can be absorbed in both directions and directed into the containment shell.

According to an advantageous embodiment of the invention it is provided that as a means for securing the stirrer head, a pin is arranged with a head, wherein the pin bearing, preferably centrally, penetrates and is fixed directly or indirectly on the split pot and the pin head absorb the axial forces of the stirrer head can. The pin head is virtually the counterpart to the front side of the gap pot. The end face of the split pot takes the axial forces in Spalttopfrichtung and the pin head absorbs the axial forces in the opposite direction. Which force component is acting depends on the design of the stirring tool and the direction of rotation of the stirrer head. If the pin penetrates the entire camp, it is possible to fix the pin from the gap pot underside on the split pot and secure. However, it is also conceivable that the pin does not penetrate the entire camp, but only screwed into a bearing core or anchored in any other way. However, it is indispensable that directly or indirectly an upper contact surface for the stirrer head, is formed for receiving the upward axial force component, wherein this contact surface, in an advantageous embodiment - the pin head, directly or indirectly attached to the containment shell or a stationary component.

It is of particular advantage that the bearing as a product-lubricated sliding bearing with a mounted in the stirrer head, preferably shrunken bearing bush and a bearing sleeve therein, wherein the pin, the bearing sleeve, preferably centrally penetrates and the lower annular surface of the pin head, the upper end surface of the bearing bush at least partly covered. The overlap is necessary so that the lower annular surface of the pin head can absorb the axial forces of the bearing bush connected to the stirrer head. The pin head thus forms a contact surface for the bearing bush. It is conceivable that the lower annular surface of the pin head is arranged at a distance from the bearing bush. As a result, a certain mobility of the stirrer head is achieved in the axial direction. The pin can serve as the sole hub of the bearing, which is concentrically enclosed by the bearing sleeve. This has the great advantage that the fixation of the pin can take place from the lower side of the split pot. However, it is also possible that the bearing sleeve does not directly surround the pin, but that an additional, connected to the gap pot, metal sleeve is provided. In this case, the pin does not force the metal sleeve penetrate completely, but can be anchored directly in the metal sleeve. The actual bearing sleeve is then arranged concentrically to the metal sleeve. Since the bearing is located in the product space and lubricated with product, the resulting minimum frictional heat is dissipated through the product. For a sufficient lubricating film between the bearing sleeve and bearing bush is provided by the flow profile and the oscillating movement in the concentric cavity between the stirrer head and split pot.

It is of particular advantage if the bearing sleeve is formed below the pin head with a collar and forms a contact surface for the upper end side of the bearing bush. The contact surface provides for the absorption of the axial forces of the stirrer. The formed with a collar bearing sleeve is at the outer edge of sealed lower ring surface of the pin head relative to this by means of an O-ring. This avoids the product being able to penetrate into the space between the bearing sleeve and the pin.

Thus, the axial direction of the stirrer head directed in the direction of the can, a contact surface for the lower end side of the bearing bush is provided below the bearing bush.

Particularly wear-free bearings are obtained when the bearing and / or the contact surfaces are made of ceramic.

To prevent twisting or even loosening of the pin, an anti-twist device is provided in the pin. For example, the pin is rotatably connected at its lower end with the containment shell. In addition, an axial lock can be attached.

It is particularly useful if the bearing bush has at least one connection opening, and the means for supplying liquid are provided through this connection opening. Thus, it is possible that from the interior of the gap pot forth a line is guided through the pin to the connection opening. Through this, a liquid can be introduced into the intermediate space between the bearing sleeve and the bearing bush.

A further advantageous possibility for introducing liquids into the intermediate space between the bearing sleeve and bearing bush is that the bearing bush is divided into two, or that at least two bearing bushes arranged one above the other in the axial direction are provided, and that means for feeding fluids, in particular lubricating but Also cleaning fluids are provided in the space between the sockets.

Both variants make it possible to introduce liquids from the inside of the can into the bearing gap.

Additional seals can be dispensed with if the containment shell is designed as a weld-in flange and is welded directly into the container wall.

The installation of the stirrer is greatly facilitated if the containment shell is designed as a Einsteckflansch and inserted from the interior of the tank through a mounting flange and then fixed and secured to the gap pot face from the outside.

According to one embodiment of the invention it is provided that in addition to the stirrer with stirring a concentric, preferably designed as a guide tube, stator is provided. By this measure, one obtains a rotor-stator system as Leitstrahlmischer or Disperspergrührwerkzeug. While the mixing of liquid components with not very different viscosities is still very simple, but the demand for the mixing element increases with increasing density and viscosity difference. While in a typical axial or radial advancing stirrer, low dissipation ratios, i. In the case of a rotor-stator system, a local high energy input to achieve certain mixing and dispersing effects is possible.

If simultaneously with the improved mixing by the use of a stator, a dispersing effect is to be achieved, it is advantageously provided that in addition to the agitator a concentric shearing ring is provided which is arranged to rotate with the agitator and that concentric to this shearing a further Scherkranz am Stator is provided. It is possible that the stator is designed as a combination between the guide tube and Scherkranz or as the sole Scherkranz. The shear gradient increases with decreasing distance between the two shear rings. The use of this development according to the invention is particularly suitable for difficult-to-mix liquid components.

Especially with large stirrers with a pin with a large diameter, it is advantageous that the pin is formed by the containment shell, or is integrally connected thereto, wherein the pin has a vertical through hole and above the pin, a fastening washer is provided with internal thread, wherein the mounting disc is arranged so that it receives the axial forces of the stirrer and through the through hole from the split pot bottom forth a screw is guided, which is screwed into the internal thread of the mounting plate and thus the Stirrer head fixed to the containment shell to prevent axial lifting. Such an embodiment is not possible with small diameter cones because then the screw would have too small a cross section. The embodiment has the advantage that it can be dispensed with the O-ring below the lower thrust washer.

To prevent twisting of the mounting plate, a locking pin is advantageously provided between pin and mounting plate. The locking pin advantageously does not come into contact with the product.

Fig. 1:

einen erfindungsgemäßen Rührer,

Fig. 2:

einen erfindungsgemäßen Rührer mit einem Rotor-Stator-System

Fig. 3:

einen Rührer mit geteilter Lagerhülse

Fig. 4:

einen Rührer mit großen Zapfen.

Three embodiments of the invention will be explained in more detail with reference to the drawings. Show it:

Fig. 1:

a stirrer according to the invention,

Fig. 2:

a stirrer according to the invention with a rotor-stator system

3:

a stirrer with split bearing sleeve

4:

a stirrer with big cones.

FIG. 1 shows a stirrer 1 according to the invention for stirring sterilizable liquids. The stirrer 1 consists of a stirrer head 2, which is rotatably mounted by means of a bearing 3. At the stirrer 1, a stirring tool 4 is provided. In this embodiment, these are stirring tools 4 for generating an axial flow.

Furthermore, a clutch 5 is provided for non-contact drive of the stirrer head 2. In this embodiment, it is a magnetic coupling 5 with a drive-side coupling part 6, which is designed as a drive magnet and a concentric arranged secondary coupling part. 7

The drive magnet 6 is connected to a drive shaft in connection, which in turn is connected to the drive, in particular an electric motor.

The drive-side coupling part 6 is arranged within a split pot 8. In the left half of the drawing, the containment shell 8 is designed as a plug-in flange. The Einsteckflansch was introduced from the container interior in a mounting flange 9 and fixed at its lower end by means of a locking ring 10. The mounting flange 9 is welded in the container 11. The Einsteckflansch is circumferentially sealed relative to the mounting flange by means of an O-ring 12.

In the right half of the drawing, the containment shell is designed as a weld-in flange. This is welded directly to the container. On the O-ring 12 and the locking ring 10 can be dispensed with advantage.

Of course, either only the Einsteckflanschvariante or Einschweißflanschvariante be selected.

The bearing 3 is designed as a product-lubricated ceramic or high-performance plastic plain bearing. However, it is also conceivable to use, for example, a ceramic ball bearing or roller bearings.

The bearing consists of a shrunk in the stirrer head 2 ceramic bushing 13 and a running therein bearing sleeve 14, also made of ceramic.

Through the center of the bearing sleeve 14, a pin 15 is guided with a head 16. The pin 15 has the hub of the bearing 3. The pin 15 has at its lower end to prevent rotation and is fixed in the containment shell 8, from below by means of a screw. The lower annular surface 18 of the pin head 16 projects beyond the upper end face 19 of the bearing bush 13.

The bearing sleeve 14 is formed with a collar which serves as a contact surface for the upper end face 19 of the bearing bush 13. The bearing sleeve 14 in turn is supported on the lower annular surface 18 of the pin head 16 and sealed with respect to this by means of an O-ring 20. Opposite the end face is a thrust washer 21 for receiving the oppositely acting axial forces of the stirrer head 2. Bearing sleeve, bearing bush and thrust washer are made of ceramic.

If designed as a Einsteckflansch gap pot 8, the bearing 3, the stirrer head 2, and the pin 15 are formed as a unit, this unit can be guided from the container interior by means of the Einsteckflansches 8 through the mounting flange 9 and fixed by means of the securing ring 10. This eliminates damage to the bearings 3 during assembly.

Between the stirrer head 2 and the split pot 8, a cavity 22 is provided, which is designed to be open at the bottom. Furthermore, 22 leading openings 23 are provided in the cavity. When the stirrer head 2 is set in rotation, a pressure difference arises in the cavity 22 relative to the rest of the container, so that the cavity is constantly traversed by liquid medium. At the same time, this airfoil provides lubricating film wetting for lubrication of the sliding bearing 3.

FIG. 2 also shows an agitator 1 according to the invention with a bearing 3, agitator 4 and a clutch for non-contact drive of the agitator head 2. Concentric with the stirring tool 4, a stator 24 is provided, which is formed in its upper region as a guide tube.

In order to achieve an additional dispersing effect, an axially aligned shearing collar 25 is provided concentrically with the axis of rotation of the stirrer head 2 at the outer ends of the stirrer 4. The stator is also formed in the opposite region as a shearing ring 26. By choosing the distance between the two Scherkränzen 25, 26, the shear gradient can be varied.

By providing the shear rings with profiling, the agitator fulfills the role of a disperser. The dispersing effect is significantly improved.

FIG. 3 likewise shows a stirrer 1 with stirrer head 2 and bearing 3. The bearing 3 contains two bearing bushes (13, 13 ') arranged one above the other in the axial direction. There is a line 27 is provided, by means of a pump, not shown, liquids, in particular of lubricating and rinsing liquids, in the space between the bushes (13, 13 ') and thus also in the bearing gap can be introduced. The feed is to be adapted constructively depending on the size of the stirrer. The wiring can be made from above, through the container, or from below, for example through the flange.

As a result, a novel possibility for flushing and cleaning of the bearing gap is given.

FIG. 4 shows a large stirrer 1, wherein the pin 15 has a larger diameter than the pins of the stirrer in FIGS. 1 to 3. The pin 15 is formed by the split pot 8 in this exemplary embodiment. In the pin 15 is a central, vertical through hole 28 is provided. Above the pin a resting on this mounting plate 29 is provided with internal thread 30. The mounting plate 29 projects beyond the upper end face of the bearing bush 13, whereby it can receive an axial force component of the stirrer head. Through the through hole 28 is from the split pot bottom her a screw 31 out, which is screwed into the internal thread 30 of the mounting plate 29 and thus the stirrer head 2 fixed to the split pot 8 and thus secures against axial lifting. Also in this embodiment, therefore, the backup takes place against axial lifting of the split pot bottom side.

In order to prevent rotation of the mounting plate 29, 29, a locking pin 32 is provided between pin 15 and mounting plate. The locking pin 32 is advantageously not in contact with product.

LIST OF REFERENCE NUMBERS

1

stirrer

2

stirrer head

3

camp

4

agitator

5

clutch

6

drive-side coupling part

7

secondary coupling part

8th

containment shell

9

mounting flange

10

circlip

11

container

12

O-ring

13

bearing bush

13 '

bearing bush

14

bearing sleeve

15

spigot

16

head

17

twist

18

lower ring surface

19

upper end of the bearing bush

20

O-ring

21

thrust washer

22

cavity

23

openings

24

stator

25

shearing crown

26

shearing crown

27

management

28

Through Hole

29

mounting disk

30

inner thread

31

Screw with fuse

32

safety pin

Claims (18)

1. A stirrer for combining substances in the liquid phase, including a stirrer head (2) with a stirring tool (4) and with a coupling (5) for contactless, inductive or magnetic drive of the stirrer head (2), and a containment shell (8) secured in a container to accommodate the drive-side coupling member (6), means (15) being provided to prevent axial lifting of the stirrer head (2), characterised in that the stirrer head (2) is prevented from lifting axially by the underside of the containment shell, a screw being provided as the means (15) for securing the stirrer head (2).
2. The stirrer as recited in claim 1, characterised in that the stirrer head (2), the bearing (3) and the means (15) for safeguarding the stirrer head (2) are conformed as a single unit.
3. The stirrer as recited in either of the preceding claims, characterised in that the bearing (3) is situated above the containment shell (8) and is particularly conformed as a combination of axial and radial bearing.
4. The stirrer as recited in any of the preceding claims, characterised in that a journal (15) with a head (16) is provided as the means for safeguarding the stirrer head (2), the journal (15) penetrates the bearing (3) preferably centrally and is fixed to the containment shell (8) either directly or indirectly, and the journal head (16) is disposed to absorb the one axial force component of the stirrer head (2).
5. The stirrer as recited in any of the preceding claims, characterised in that the bearing (3) has the form of a lubricated sliding bearing with a bearing bush (13) mounted, preferably shrink-fitted, in the stirrer head (2), and a bearing sleeve (14) moving therein, the journal (15) penetrating the bearing sleeve (14) preferably centrally and the lower annular bearing surface of the journal head (16) at least partly covers the upper frontal face (19) of the bearing bushing (13).
6. The stirrer as recited in any of the preceding claims, characterised in that the bearing sleeve (14) is conformed with a collar below the journal head (16), thus forming a thrust surface for the upper frontal face (19) of the bearing bushing (13).
7. The stirrer as recited in any of the preceding claims, characterised in that a thrust surface for the lower frontal face of the bearing bushing (13) is provided below the bearing bushing (13).
8. The stirrer as recited in any of the preceding claims, characterised in that the bearing (3) and/or the thrust surfaces are made from ceramic or high-performance plastic.
9. The stirrer as recited in any of the preceding claims, characterised in that the journal is equipped with an anti-twist device.
10. The stirrer as recited in any of the preceding claims, characterised in that the bearing bushing (13) is furnished with at least one connection aperture, and that means are provided for supplying liquid, particularly lubricant and flushing fluid, through this connection aperture into the bearing gap.
11. The stirrer as recited in any of the preceding claims, characterised in that at least two bearing bushings (13) are provided and are disposed axially one above the other, and that means are provided for supplying liquid, particularly lubricant and flushing fluid, to the cavity between the bushings.
12. The stirrer as recited in any of the preceding claims, characterised in that the containment shell (8) is realised as a welding flange.
13. The stirrer as recited in any of the preceding claims, characterised in that the containment shell (8) is realised as a fitting flange.
14. The stirrer as recited in claim 13, characterised in that the fitting flange is secured against axial displacement via a locking feature.
15. The stirrer as recited in any of the preceding claims, characterised in that a concentric stator (24), preferably realised as a conduit tube, is provided in addition to the stirrer head (2) with stirring tool (4).
16. The stirrer as recited in any of the preceding claims, characterised in that a concentric shearing crown (25) is provided in addition to the stirring tool (4), and is situated so as to rotate with the stirring tool (4), and that a shearing crown (26) concentric with this shearing crown (25) is provided on the stator (24).
17. The stirrer as recited in any of the preceding claims, characterised in that the journal (15) is formed by the containment shell (8), or is attached integrally thereto, wherein the journal (15) is furnished with a vertical through hole (28), and a fixing disc (29) with internal thread (30) is provided above the journal (15), wherein the fixing disc (29) is disposed in such manner that it absorbs an axial force component of the stirrer, wherein a screw (28) is passed through the through hole (3) from the underside of the containment shell, and is screwed into the internal thread (3) of the fixing disc (29), thus preventing the stirrer head (2) from lifting axially.
18. The stirrer as recited in claim 17, characterised in that a locking pin (32) is provided between the journal (15) and the fixing disc (29).

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