DE20114076U1 - Homogenizer, especially for the bottom of a mixing and stirring tank - Google Patents

Description

DESCRIPTION

Homogenizer, especially for the bottom of a mixing and stirring vessel

The invention relates to a homogenizer, in particular for a base for mixing and stirring containers, with an axially extending structure, a housing with a first fastening flange, a second flange, a stator and a rotatable rotor acting with the latter at a sufficient thrust rate, as well as a drive shaft which projects through the first fastening flange into the interior of the container.

Homogenizers of this type are known for use in processes in the chemical, fiber, food and pharmaceutical industries, for example. They offer a particularly high level of product protection, for example in the area of mixing technology, for example during homogenization, suspension, emulsification, dispersing, dissolving, dehydration, extraction, gassing, vacuum degassing, etc., where mixing or agitating devices, also known simply as mixers, are used in the production of e.g. pharmaceutical and cosmetic emulsions, ointments, pastes, creams and gels, as well as highly viscous chemical and food products. Mixers of this type have a mixing or agitating container, which is usually cylindrical (pot) shape and has a homogenizer in the lower (container) base, which is usually a dished bottom, which meets the high requirements of sterile process technology and which, for example, B. sterile mixtures to be homogenized are not contaminated.

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A homogenizer is used for homogenization, i.e. mixing immiscible liquids or particles, e.g. fat and water or graphite and water, ultimately by sufficiently crushing the components. This smallest distribution of one substance in another in such a way that its particles float in the other substance is also known as dispersion. This means that to produce emulsions, suspensions or aerosols etc. not only convection and surface exchange are necessary, but also particle crushing. Only in this way is it possible to incorporate the disperse phase into the continuous phase in such a way that the mixture, the dispersion, remains stable over a long period of time. It is known that the extremely high shear and thrust conditions required for this can be met with appropriately toothed rotors and stators, which have a certain shear gap between the rotating teeth.

The company IKA Werke GmbH & Co. KG, 7 9219 Staufen, DE, is known for its dispersing machines with the type designation "ULTRA-TURAX® Type UTE-TP 150/4-P-PH" for installation in open or closed containers and for sterile process control.

The dispersing machine known from this has a housing and is arranged by means of a fastening flange in a correspondingly designed through-opening, preferably in the bottom of a mixing container. The fastening flange is firmly and tightly connected to a central shaft bushing, which is connected by means of a high-quality mechanical seal with several special shaft seals and/or sliding rings made of silicon carbide, essentially externally lubricated and externally

■ cooled, a drive shaft or a drive shaft support is mounted. The drive shaft rotates a disk-shaped rotor with rotor teeth distributed around the outer circumference, the teeth of which rotate at a radial distance from corresponding teeth of a stator fixed to the mounting flange. The drive shaft is driven by a drive, an electric motor with approx. 3000 revolutions per minute. The electric motor is screwed to the dispersing machine via a flange. Although this dispersing machine is suitable for sterile use due to the use of sterile coolant and lubricant, contamination via the mechanical seal is still possible. Contamination of the mixed material with the lubricant and coolant always occurs with mechanical seals due to the design and cannot be completely ruled out even with a design with exclusive self-lubrication. In the case of external lubrication and cooling, the lubricant and coolant must also be checked, spread and circulated. This also requires considerable design and process engineering effort, which usually even has to include a pressure vessel with accessories, which has a negative impact on the high purchase price and also on the operating costs. Accordingly, corresponding dispersing machines only ever lead to quasi-sterile process results within the design-specified tightness limits.

The homogenizers known in the state of the art for sterile operation, in particular the above-mentioned dispersing machines, are, due to the technically complex construction in the high-cost range and the nevertheless not 100% avoidable risk of contamination for

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the mixed material, is not very suitable for satisfactorily solving the problem of the present invention.

The object of the present invention is to provide a homogenizer, in particular for the bottom of a mixing and stirring vessel, which does not have the above disadvantages, has a simple construction, is virtually maintenance-free and self-lubricating and 100% and permanently meets the requirements of sterile process technology.

This object is achieved according to the invention in that a hat-shaped, tight and at least partially magnetically permeable cap is arranged firmly and tightly on the side of the first fastening flange in the container bottom facing into the interior of the container, the cap projects into the container and encloses the end section of the drive shaft in the container and a magnetic drive drives the rotor.

Surprisingly, it has been possible to design the drive for the rotor in the container to be magnetic, despite the high power to be transmitted, which is necessary for the shear and thrust conditions and/or the thrust rate for homogenization with the considerable speeds and torques, and to enable 100% hermetic sealing of the container to the outside, even in the area of the homogenizer, and at the same time to provide only quasi-self-lubricating components, at least those located inside the container and which need to be cleaned.

According to the application, it is advantageously provided that the cap is rotationally symmetrical and in axial

Extension has a central bearing pin to accommodate a bearing for a bearing ring of the rotor. This provides a structurally simple and at the same time robust and precise bearing for the rotor. The dimensions of the bearing pin are virtually completely free and can be designed based solely on the strength requirements, it is accessible at any time from the inside of the container and is washed around by the mixed material. Due to the magnetic drive, further axial locking of the bearing ring can actually be dispensed with.

It is also advantageous that the bearing journal has a central threaded blind hole in its front face to accommodate a screw connection for securing at least one inner and/or outer plain bearing ring. This ensures that the inner plain bearing ring is firmly seated, which can be reached via the easily accessible screw connection. It should be noted here that the screw connection can be dimensioned in such a way that an outer plain bearing ring is also secured accordingly. Due to the significant axial load on the screw connection, it can be implemented using a conventional screw with any screw head, including a hexagonal one, and if necessary a washer with the appropriate diameter.

It is also advantageous that the bearing ring is bush-shaped, accommodates the outer sliding ring of the plain bearing and the screw connection has a bow-like grip. The axial extension of the bushing ensures in particular a tilt-free and thus smooth and low-wear rotation of the bushing, i.e.

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of the bearing ring, and thus ultimately of the rotor supported by it. The bow-shaped handle enables easy and precise handling (assembly or disassembly) of the rotor. In addition, the handle protects against improper contact with the screw connection underneath and the parts of the plain bearing.

According to the application, it is also advantageously provided that the bearing ring has at least two bracket-shaped

1-0 type arms that hold a drive ring close to and at a distance from the outer surface of the cap. This advantageously creates a rotationally symmetrical fastening for the drive ring that hangs when aligned normally. It should be noted at this point that in this application "top" and "bottom" always refer to a vertical axial alignment of the homogenizer, with the rotor pointing upwards. The bow-like arms move the mixed material at the same time. For design reasons, additional arms can also be provided. Due to the precise guidance, the distance to the outer surface, which, as explained below, forms part of the magnetic gap, can be extremely small.

According to the application, it is advantageously provided that the drive ring is made of one piece or several pieces and is sealed and hollow and accommodates at least one permanent magnet with a radial effect on the drive shaft and forms a central section of the rotor via radial spokes, the rotor teeth of which point orthogonally away from the first fastening flange with their free ends. This allows a structurally simple and extremely robust as well as aerodynamic design of the connection of the drive ring to the rotor or its bearing.

This is because the drive ring is self-contained and accommodates the permanent magnet and at the same time forms the hub of the rotor plate of the rotor. This can be a simple welded or screwed construction. The radial distance between the drive ring and the rotor teeth is completely free pointing into the container, so that incoming mixed material can reach the functional area of the rotor and stator unhindered and continuously.

The latter is ensured by the special orthogonal alignment of the rotor teeth, which extends into the container. The field lines of the permanent magnet are aligned radially and thus have the greatest effect.

It is also advantageous that the stator is fixedly arranged on a flange of the cap, with stator teeth that form a shear gap with the rotor teeth at a radial distance and end with the rotor teeth in the axial extension. The flange of the hat-shaped cap thus almost automatically forms a required base for the stator or its stator teeth, which can thus be precisely assigned to the rotor teeth, forming a desired shear gap, and these can also be adapted to the rotor teeth in the axial extension.

It is advantageous that the flange is an integral part of the cap and is firmly and tightly connected to the floor either directly or via a flange ring welded into the floor. This is a structurally simple solution that ensures absolute tightness of the container and thus sterility of the mixed material and is preferably used on flat floors.

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is used. In the case of a dished bottom, a flange ring can be welded into the dished bottom to create a corresponding support surface. The flange of the cap is usually connected directly to the bottom or to the flange ring and sealed against it with an O-ring.

According to the application, it is advantageously provided that at least the outer surface of the cap and the inner outer surface of the drive ring are extremely thin-walled and made of magnetically permeable material. This makes it possible to have a small air gap, which is necessary for the magnetic force transmission, which is also secured by the precise guidance of the rotor and the drive shaft, as explained later.

Furthermore, it is advantageously provided that the sliding bearing is made of a PTFE-graphite compound or graphite compound or silicon carbide and a sealing ring between the flange of the cap and the base or the flange ring is made of a polymer. This ensures that the homogenizer can be dismantled easily and at the same time satisfies the sterile process technology.

According to the application, it is further provided that the end section of the drive shaft has a bushing inside the cap and at a distance from the cap, which integrally accommodates at least one permanent magnet with a radial field path in or on its outer surface. This achieves a process-related advantage that has an extremely cost-reducing effect. This is because only a bushing with a permanent magnet in the required quality needs to be manufactured and not, as

otherwise usual, a complete shaft. If repairs are required, it is also possible to replace only a defective shaft or a defective bushing, while the other component can continue to be used.

It is also advantageous that the end section of the drive shaft opposite the bushing has an end face with a central blind hole for receiving a shaft of a drive means and ends in the housing. This enables extremely cost-effective mounting of the bushing, which in particular makes use of the short longitudinal extension of the drive shaft and therefore does not require any additional mounting of the drive shaft. If required, there is also sufficient space in the housing for this.

It is also advantageous that the blind hole interacts with the shaft of the drive means in a fixed and removable manner and has a radial shaft lock. In this way, i.e. solely through the choice of coupling, a sufficiently fixed and at the same time removable connection can be created, which only has a shaft lock, e.g. via a tongue and groove connection.

Furthermore, it is advantageously provided that the drive shaft can be dismantled together with the bushing and the drive means. This makes the homogenizer according to the invention particularly easy to assemble, maintain and repair. All moving parts on the outside of the container can thus be dismantled with one move.

According to the application, it is also advantageously provided that an electric motor with several thousand revolutions per minute forms a drive means with geometries that are coordinated with one another in such a way that a peripheral speed of several tens of m/sec can be achieved at the shear gap. This ensures the physical conditions of dispersion, etc., without having to use special, non-commercially available components. Due to the direct coupling, commercially available electric motors and standard rotors and stators can be used, for example.

Further preferred embodiments of the invention emerge from the subclaims. An embodiment of the invention is explained in more detail with reference to a drawing. Therein shows:

Fig. 1 is a schematic longitudinal section through a homogenizer according to the invention mounted in a base, and

Fig. 2 is a schematic plan view of a homogenizer according to the invention according to arrow A in Fig. 1.

Fig. 1 shows a schematic longitudinal section through a homogenizer 10 according to the invention, which is arranged in a (container) bottom 11 of a mixing container (not shown in more detail). The orientation of the rotationally symmetrical homogenizer 10 shown in Fig. 1, with its essentially vertical longitudinal extension, with a lower drive means 12 and an upper section with a stator 13 and a rotor 14 inside the mixing container, corresponds to the orientation referred to in this application. It also corresponds to the preferred

Installation position of the homogenizer 10 in or on a mixing container. The bottom 11 of the mixing container shown is a so-called dished bottom. The assembly in such a dished bottom is carried out by means of a flange ring 15 which is welded to the through opening 16 in the bottom 11. The flange 17 of a cap 18 is screwed to this flange ring 15 from the outside and below by means of several screws 19 and is sterilely sealed to the inside of the mixing container via a sealing ring 20 to the flange ring 15.

Particularly in the case of a flat base 11, a welded-in flange ring 15 can be dispensed with and the flange 17 of the cap 18 can be screwed directly to the base 11 in the area of the through-opening by means of screws 19. The sealing ring 20 then seals the mixing container between the flange 17 and the through-opening 16 in a sterile manner in the same way.

A first fastening flange 21 of a housing 22 engages from the outside and below into the flange 17 of the cap 18 and is fixedly arranged on the flange 17 by means of screws 23. According to the application, a special sealing of this connection is not required.

The homogenizer 10, which is essentially rotationally symmetrical, is equipped with a further second flange 24 at the lower end of the housing, which serves to connect to a flange of a drive means 12, for example an electric motor. According to the application, this connection also does not require any special sealing.

The surface of the flange 17 of the cap 18 facing into the mixing container serves as a fixed support for fastening the stator 13, which is also rotationally symmetrical and has a circular base with an outer annular edge formed by stator teeth 25 which are arranged longitudinally away from the flange 17 and have a greatest height which corresponds to that of the rotor teeth 26, with which the stator teeth 25 form a radial shear gap 27.

The flange 17 is an integral, one-piece component of the rotationally symmetrical and hat-shaped cap 18, which has an extremely thin outer surface 28 that extends into the interior of the mixing container and has an integral cover section 29 that closes the cap 18 that projects into the interior in this area. The mixing container is thus completely closed by means of the cap 18 according to the application. The cap 18 is thus an integral component of the container base 11.

The rotor 14 is firmly connected to a drive ring 31 via two or more radial webs or spokes 30 distributed around the circumference, which essentially completely encloses the outer surface 28 of the cap 18 and is in turn attached to a bush-shaped bearing ring 33 with bearing 49 by means of two or more arms 32 distributed symmetrically around the circumference. The arms 32 serve, in addition to their function as a fastening, also to move the mixed material. The bush-shaped bearing ring 33 encloses a bearing pin 34 and can be placed on the bearing pin 34 in the direction of arrow A in a freely accessible manner from above. The bearing ring 33 and the bearing pin 34 are each provided with a sliding ring 35, preferably

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made of a PTFE graphite compound or graphite compound or silicon carbide and work together in a self-lubricated/self-cooled manner through the mixture. The bearing ring 33 also has a bow-shaped handle 36 for handling it, and the bearing journal 34 has a threaded blind hole 38 in its upper face 37 for receiving a screw connection 39 for axially locking at least the inner sliding ring 35. If a slightly larger diameter of the screw connection 39 or an additional disk with a larger diameter is selected, the outer sliding ring 35 or even the bearing ring 33 itself can be secured at the same time.

The drive ring 31 is hollow and can be constructed in one or more pieces, is in any case tightly and firmly closed and has in its cavity at least one permanent magnet 40, the field lines of which point radially inward and penetrate the inner, magnetically permeable surface 41.

Inside the cap 18, an end section of a drive shaft 42 is arranged, which is provided with a bushing 43, which also integrally accommodates at least one permanent magnet 40 on its outer circumference, the field lines of which emerge radially outwards and penetrate the magnetically permeable material of the outer surface 28 of the cap 18 and come into action with the drive ring 31 via the narrow air gap thus formed and forms the magnetic drive.

The downward pointing end section of the drive shaft 42 ends axially in the housing 22 and has a central blind hole 45 in its front surface for coupling with

a shaft 46 of the flanged drive means 12. The clearance between the blind hole 45 and the shaft 46 is such that the drive shaft 42 itself does not need to be further supported. Furthermore, a shaft lock 47, which essentially acts against slip, is advantageously provided in the area of the blind hole 45.

According to the application, by dismantling the drive means 12, the drive shaft 42 can be dismantled together with its bushing 43. In the event of a necessary repair, the bushing 43 can even be separated from the drive shaft 42.

Fig. 2 shows a schematic top view of the homogenizer 10 according to arrow A in Fig. 1. The homogenizer 10 is clearly constructed in a rotationally symmetrical manner. From the inside to the outside, the handle 36, which spans the bearing ring 33, is shown first. The bearing ring 33 is in turn arranged via the sliding rings 35 of the sliding bearing 49 on the invisible bearing journal 34 below the screw connection 37. The cover section 29 of the hat-shaped cap 18 can be seen between the three arms shown. The drive ring 31 follows radially outwards, which is provided, for example, with three webs 30 that create a firm connection between the drive ring 31 and the outer ring-shaped edge of the rotor 145, which is provided with the required number of specially shaped rotor teeth 26. A barely visible shear gap 27 then follows radially outwards to the ring of stator teeth 25 of the stator 13.

The flange ring 15 and the flange 24 with partially shown screw connections 48 of the drive means 12 then follow radially outwards. The flange 24 and the screw connections 48 are visible because the base 11 is not shown here.

The features of the invention disclosed in the above description, in Figures 1 and 2 and in claims 1 to 15 may be essential for the realization of the invention in its different embodiments both individually and in any combination.

Claims (15)

1. Homogenizer, in particular for the bottom of a mixing and stirring container, with an axially extending structure, a housing with a first fastening flange, a second flange, a stator and a rotatable rotor acting with the latter at a sufficient thrust rate, and a drive shaft which projects through the first fastening flange into the interior of the container, characterized in that a hat-shaped, tight and at least partially magnetically permeable cap ( 18 ) is arranged firmly and tightly on the side of the first fastening flange ( 21 ) facing the interior of the container in the container bottom ( 11 ), the cap ( 18 ) projects into the container and encloses the end section of the drive shaft ( 42 ) in the container, and a magnetic drive drives the rotor ( 14 ). 2. Homogenizer according to claim 1, characterized in that the cap ( 18 ) is rotationally symmetrical and has a central bearing pin ( 34 ) in its axial extension for receiving a bearing ( 49 ) for a bearing ring ( 33 ) of the rotor ( 14 ). 3. Homogenizer according to claim 2, characterized in that the bearing pin ( 34 ) has in its front surface ( 37 ) a central threaded blind bore ( 38 ) for receiving a screw connection ( 39 ) for securing at least one inner and/or outer plain bearing ring ( 35 ). 4. Homogenizer according to claim 3, characterized in that the bearing ring ( 33 ) is bush-shaped, receives the outer sliding ring ( 35 ) of the sliding bearing ( 49 ) and the screw connection ( 39 ) has a bow-like handle ( 36 ) extending across it. 5. Homogenizer according to claim 4, characterized in that the bearing ring ( 33 ) has at least two bracket-like arms ( 32 ) distributed around the circumference, which hold a drive ring ( 31 ) close to and at a distance from the outer surface ( 28 ) of the cap ( 18 ). 6. Homogenizer according to claim 5, characterized in that the drive ring ( 31 ) is in one piece or in several pieces and is tight and hollow and accommodates at least one permanent magnet ( 40 ) with a radial effect to the drive shaft ( 42 ) and forms a central section of the rotor ( 14 ) via radial spokes ( 30 ), the rotor teeth ( 26 ) of which point with their free ends orthogonally away from the first fastening flange ( 21 ). 7. Homogenizer according to claim 6, characterized in that the stator ( 13 ) is fixedly arranged on a flange ( 17 ) of the cap ( 18 ), with stator teeth ( 25 ) which form a shear gap ( 27 ) at a radial distance with the rotor teeth ( 26 ) and end in axial extension with the rotor teeth ( 26 ). 8. Homogenizer according to claim 7, characterized in that the flange ( 17 ) is an integral part of the cap ( 18 ) and is firmly and tightly connected to the base ( 11 ) directly or via a flange ring ( 15 ) welded into the base ( 11 ). 9. Homogenizer according to claim 8, characterized in that at least the outer surface ( 28 ) of the cap ( 18 ) and the inner outer surface ( 41 ) of the drive ring ( 31 ) are extremely thin-walled and made of magnetically permeable material. 10. Homogenizer according to claim 9, characterized in that the sliding bearing ( 49 ) is made of a PTFE-graphite compound or graphite compound or silicon carbide and a sealing ring ( 20 ) between the flange ( 17 ) of the cap ( 18 ) and the base ( 11 ) or the flange ring ( 15 ) is made of a polymer. 11. Homogenizer according to one or more of the preceding claims, characterized in that the end section of the drive shaft ( 42 ) has a bushing ( 43 ) inside the cap ( 18 ) and at a distance from the cap ( 18 ) which integrally accommodates at least one permanent magnet ( 40 ) with a radial field profile in or on its outer surface. 12. Homogenizer according to claim 11, characterized in that the end portion of the drive shaft ( 42 ) opposite the bushing ( 43 ) has an end face ( 44 ) with a central blind hole ( 45 ) for receiving a shaft ( 46 ) of a drive means ( 12 ) and ends in the housing ( 22 ). 13. Homogenizer according to claim 12, characterized in that the blind hole ( 45 ) cooperates firmly and detachably with the shaft ( 46 ) of the drive means ( 12 ) and has a radial shaft lock ( 47 ). 14. Homogenizer according to claim 13, characterized in that the drive shaft ( 42 ) can be dismantled together with the bushing ( 43 ) and the drive means ( 12 ). 15. Homogenizer according to one or more of the preceding claims, characterized in that an electric motor with several thousand revolutions/minute forms a drive means ( 12 ) with geometries coordinated with one another in such a way that a peripheral speed to the shear gap ( 27 ) of several tens of m/sec can be achieved.