EP2181770B1 - Centrifuge - Google Patents

Description

The invention relates to a centrifuge according to the preamble of independent claim 1. Such a centrifuge is made, for example EP-A-1849524 known.

For drying wet substances or moist substance mixtures centrifuges in various embodiments are widely used and are used in a variety of fields. Thus, for example, for the drying of high-purity pharmaceutical products, discontinuously operating centrifuges, such as peeler centrifuges, are preferably used, whereas, in particular, when continuously large quantities of a solid-liquid mixture are to be separated, continuously operating pusher centrifuges are advantageously used. Depending on the requirements, one-stage or multi-stage pusher centrifuges, as well as so-called dual-pusher centrifuges, are used.

Peel centrifuges, in particular horizontal peeler centrifuges are driven by a rotary drive, usually by an electric motor, for example, via a toothed belt with a drive shaft Centrifuge centrifuge drum is connected and so the centrifuge drum is set in rapid rotation.

In Fig. 1 such a known arrangement is shown very schematically. The centrifuge 1 'comprises a centrifuge drum 3' which has a drive shaft 4 'lying in a rotation axis 2' of the centrifuge drum 3 ', a drive belt 40' non-rotatably connecting the drive shaft 4 'to a drive axle 51' of an electric rotary drive 5 ', so that in the operating state the centrifuge drum 3 'is set in rapid rotation by the electric rotary drive 5' via the drive shaft 51 ', the drive belt 40' and finally via the drive shaft 4 '.

The dehumidified solid cake K 'is thereby discharged through an opening 30' of the centrifuge drum 3 'downwards through an ejection hopper 31' from the centrifuge drum 3 ', wherein in particular in high-purity products, e.g. for pharmaceutical products, the discharge funnel 31 'leads directly into a clean room R'.

The drive shaft 4 ', to which the drive belt 40' engages, is arranged concentrically in the discharge funnel 31 'and the drive belt 40' and the drive shaft 4 'are encapsulated in a housing 400' as a rule, so that the interior of the centrifuge drum 3 ' and the clean room R 'are securely sealed against all components of the drive system.

This structurally rather complicated solution has hitherto been necessary, since, in addition to other reasons well known to those skilled in the art, the rotary electric drive 5 'had to be isolated as much as possible from gases emerging from the centrifuge drum. In a whole series of product classes or dehumidification processes, solvents are used in the centrifuge drum 3 ', or the product to be dehumidified contains solvents which, together with atmospheric oxygen, form highly explosive gaseous mixtures can, for example, by sparking in the electric rotary drive 5 'could be exploded.

Therefore, in addition to reasons of cleanliness, hygiene, etc., in the known centrifuges it was imperative to place the electric rotary drive 5 'so remote from the centrifuge drum 3' and to isolate from the inside thereof that both contaminations by the electric rotary drive 5 'and any risk of explosion were excluded.

However, this security was bought at a number of serious disadvantages.

Thus, the entire construction of centrifuge and electric rotary drive occupies a considerable space. By standing under considerable bias drive belt, the drive shaft is under a considerable tensile or bending load. To compensate for this, the drive shaft of the centrifuge drum must be stored in a complex storage device with multiple axially offset bearings, usually at least three bearings are provided in a known storage device, which are arranged at a great axial distance from each other, so that under strong tensile or Bending load standing drive shaft can be stored safely. As a result, the bearings are large in size, have a high weight and are complicated in construction. In addition, the correct tension of the drive belt is difficult to adjust, and must be corrected after a certain number of operating hours.

Overall, the construction of drive structure with motor plate, drive belt, pulleys, mudguards, etc. is very complex and generally unfavorable because the focus of the overall system outside the machine axis, which has an extremely negative effect on the damping of the entire system.

Last but not least, the drive belt develops a high level of noise during operation, which is not only unpleasant, but also questionable for reasons of safety at work, since the operating personnel are exposed to high noise levels, which can lead to permanent damage to health.

The object of the invention is therefore to propose an improved centrifuge which largely avoids the disadvantages known from the prior art.

The problem-solving objects of the invention are characterized by the features of independent claim 1.

The dependent claims relate to particularly advantageous embodiments of the invention.

The invention thus relates to a centrifuge for separating a mixture into a solids cake and into a liquid phase, comprising a rotatable about a rotation axis centrifuge drum, wherein the centrifuge drum is rotatably connected via a lying in the axis of rotation drive shaft with an electric rotary drive for rotational drive of the centrifuge drum. According to the invention, a central drive shaft of the electric rotary drive is connected in a rotationally fixed manner axially aligned with the drive shaft of the centrifuge drum.

In a particularly important embodiment for practice, the rotary electric drive is encapsulated by an encapsulation, so that within the enclosure an atmosphere of inert gas can be produced.

In this case, the drive shaft is preferably mounted in first bearing devices and a second bearing device of a bearing device, wherein the first bearing device is arranged offset in relation to the second bearing device in the axial direction along the axis of rotation. In particular, the first bearing device and / or the second bearing device is a tapered roller bearing.

In order to achieve a higher smoothness of the centrifuge drum and to minimize the wear in the bearings, the bearing device may comprise in a conventional manner, a biasing means for biasing the first bearing means and / or the second bearing means, wherein the biasing means is preferably formed by a spring.

For cooling the rotary drive and / or for cooling the storage device, a cooling device can be provided very advantageously, wherein the cooling device for exchanging coolant preferably comprises a coolant supply and a coolant discharge and the coolant is often water in practice.

In particular, the storage device and / or the cooling device is also provided within the enclosure.

In an embodiment which is important for practice, a sealant, for example in the form of a seal for sealing the rotary drive with respect to a product space and / or an ambient atmosphere, is preferably provided on the encapsulation so that, for example, no highly explosive solvent can penetrate into the encapsulation.

In particular, the centrifuge is a discontinuous centrifuge, preferably the centrifuge is a peeler centrifuge, in particular a vertical and / or a horizontal peeler centrifuge.

Fig. 1

schematisch eine aus dem Stand der Technik bekannte Zentrifuge;

Fig. 2

eine erfindungsgemässe Schälzentrifuge;

Fig. 3

Lagervorrichtung mit Antriebswelle einer erfindungsgemässen Schälzentrifuge;

The invention will be explained in more detail below with reference to the schematic drawing. Show it:

Fig. 1

schematically a known from the prior art centrifuge;

Fig. 2

a peeler centrifuge according to the invention;

Fig. 3

Bearing device with drive shaft of a peeler centrifuge according to the invention;

Fig. 1 shows a schematic representation of a known from the prior art horizontal peeler centrifuge with laterally mounted electric rotary drive. There Fig. 1 has already been discussed in detail at the beginning, a further discussion of this state of the art is unnecessary at this point.

In Fig. 2 is schematically sketched a horizontal peeler centrifuge according to the present invention, wherein Fig. 3 a little more detailed the bearing device of the Fig. 2 shows. It goes without saying that the invention is not based on peeler centrifuges or even on horizontal peeler centrifuges Fig. 2 respectively. Fig. 3 is limited. Rather, an electric drive according to the present invention can also be advantageously used in other types of centrifuge, which are all well known to the person skilled in the art.

For a better distinction of the present invention from the known from the prior art centrifuges according to Fig. 1 , carry reference numbers in the Fig. 2 and Fig. 3 illustrated features of the invention centrifuges no apostrophe, while the Reference numerals of Fig. 1 , which refers to the state of the art, are provided with apostrophe.

The inventive centrifuge 1 according to Fig. 1 for separating a mixture into a solid cake and into a liquid phase, comprises a rotatable about a rotation axis 2 centrifuge drum 3, the centrifuge drum 3 is connected via a lying in the rotation axis 2 drive shaft 4 with an electric rotary drive 5 for rotational drive of the centrifuge drum 3 directly rotatably connected , According to the present invention, a central drive shaft 51 of the electric rotary drive 5 is axially connected in a rotationally fixed manner to the drive shaft 4 of the centrifuge drum 3.

That is, the electric rotary drive 5, which may be, for example, a commercially available electric motor 5 for driving a machine tool, such as for driving a lathe, is connected with its drive shaft 51 directly and axially aligned with the drive shaft 4 of the centrifuge drum 3.

This is possible because in the specific example of the Fig. 2 the bearing device 8 with first bearing means 81 and second bearing means 82, which are designed here as tapered roller bearings 81, 82, in which the drive shaft 4 of the centrifuge drum 3 is mounted, together with the electric rotary drive 5 in an encapsulation 6 is encapsulated such that the interior the encapsulation 6, so in particular the electric rotary drive 5 and the bearing device 8 are securely sealed against the external environment.

The interior of the enclosure 6 is flooded with an inert gas 7, for example with nitrogen 7 or a noble gas 7, so that any risk of explosion, for example by sparking in the electric rotary drive. 5 is excluded. The inert gas 7 is introduced via the schematically indicated by the arrow 7 feed into the enclosure 6.

Since considerable amounts of heat can form in the electric rotary drive 5 or in the storage device 8 during operation, a cooling device 9 is provided, in which water is supplied in the encapsulation 6 via the coolant supply 91 and coolant via the coolant discharge 92 in the present example as a coolant is dissipated.

Furthermore, a connection 11 can be seen, can be added to the other operating materials, such as lubricant and / or discharged, and an electrical connection 12 via the electric rotary drive 5 electrical energy can be supplied or via the example, electrical control signals or also sensor signals of all kinds can be exchanged.

In Fig. 3 is the storage facility according to Fig. 2 shown in more detail. Clearly visible is the drum hub 300 via which the drive shaft 4 in a conventional manner rotatably connected to the centrifuge drum 3 and the two tapered roller bearings 81, 82, in which the drive shaft 4 is securely stored. Since no tensile forces acting on the drive shaft 4 by a drive belt, the two tapered roller bearings 81, 82 are arranged in a relatively small distance in the axial direction along the axis of rotation 2 to each other, whereby the bearing device is less expensive, more compact and thus lighter, cheaper and less susceptible to interference, as the storage devices known from the prior art.

In Fig. 3 is the interior of the enclosure 6 while sealed with special seals 10 safe to the outside.

In summary, the advantage of the present invention are obvious: the fact that no tensile forces act on the storage of the centrifuge drum, a small bearing clearance can be achieved through the use of tapered roller bearings, resulting in a very compact design of the bearing device. The drive shaft of the engine is only torsioned. The assembly and disassembly of the drive and bearing device is considerably simplified and the maintenance intervals are significantly greater, since the loads on drive and storage are significantly reduced. Overall, the machine dimensions are significantly reduced and a low center of gravity of the centrifuge is achieved, which is also symmetrical in the machine axis, resulting in a significantly better running behavior and less vibration in the operating condition. The drive noise is drastically reduced and the risk of accidents is significantly reduced, because all moving parts of the centrifuge are completely and safely encapsulated. Since no drive belt must be brought to the drive shaft, the centrifuge drum can be performed with symmetrical spokes, which also increases the smoothness significantly.

Overall, space and weight is saved by the more compact design and the use of erfindunsgemässen centrifuge operating costs, especially the energy costs and maintenance costs can be significantly reduced.

Claims (12)

1. A centrifuge for separating a mixture into a solid cake and into a liquid phase, comprising a centrifuge drum (3) rotatable about an axis of rotation (2), wherein the centrifuge drum (3) is rotationally fixedly connected via a drive shaft (4) disposed in the axis of rotation (2) to an electrical rotary drive (5) for the rotational drive of the centrifugal drum (3); and wherein a central drive axle (51) of the electrical rotary drive (5) is rotationally fixedly connected in an axially aligned manner to the drive shaft (4) of the centrifugal drum (3), characterized in that the drive shaft (4) is supported in first bearing devices (81) and in a second bearing device (82) of a bearing apparatus (8) and the first bearing device (81) is arranged displaced with respect to the second bearing device (82) in the axial direction along the axis of rotation (2) and the first bearing device (81) and/or the second bearing device (82) is/are a tapered roller bearing (81, 82).
2. A centrifuge in accordance with claim 1, wherein the electrical rotary drive (5) is encapsulated by an encapsulation (6) such that an atmosphere of inert gas (7) can be established within the encapsulation (6).
3. A centrifuge in accordance with one of the claims 1 or 2, wherein the bearing apparatus (8) comprises a preload device for preloading the first bearing device (81) and/or the second bearing device (82).
4. A centrifuge in accordance with claim 3, wherein the preload device is formed by a spring.
5. A centrifuge in accordance with any one of the preceding claims, wherein a cooling device (9) is provided for cooling the rotary drive (5) and/or for cooling the bearing apparatus (8).
6. A centrifuge in accordance with claim 5, wherein the cooling device (9) comprises a coolant infeed (91) and a coolant outlet (92) for exchanging coolant.
7. A centrifuge in accordance with one of the claims 5 or 6, wherein the coolant is water.
8. A centrifuge in accordance with any one of the preceding claims, wherein the bearing apparatus (8) and/or the cooling device (9) is/are provided within the encapsulation (6).
9. A centrifuge in accordance with any one of the preceding claims, wherein a sealant (10) is provided for sealing the rotary drive (5) with respect to a product space and/or with respect to an environmental atmosphere.
10. A centrifuge in accordance with claim 9, wherein the sealant (10) is provided at the encapsulation (6).
11. A centrifuge in accordance with any one of the preceding claims, wherein the centrifuge is a discontinuously operating centrifuge.
12. A centrifuge in accordance with any one of the preceding claims, wherein the centrifuge is a knife-discharge centrifuge, in particular a horizontal knife-discharge centrifuge.

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