HK1069141B - Self-distributing centrifuge and its deviation ring - Google Patents

Description

Automatic discharging type centrifuge and guide ring thereof

Technical Field

The present invention relates to a device for separating liquids and solids in a centrifuge, in particular an automatic discharge disc separator. The invention relates in particular to a paste guide ring for an automatic discharge centrifuge and having an annular baffle wall and to an automatic discharge centrifuge.

Background

A disk separator is a centrifuge equipped with a central inlet for the suspension, wherein a conical disk is located in the drum, which acts as a fine particle separator by the centrifugal forces present and a short settling path. The separated particles slide along the discs into a solids collection chamber until reaching the coarsest part of the drum. The clarified liquid is discharged without pressure through an overflow weir or under pressure through a so-called scoop designed in the form of a pump impeller.

For the case of low solids, a disk separator with a closed drum which has to be emptied by hand is used. If there are more solids, the drum is equipped with an emptying device which allows the discharge of all the objects contained in the drum and containing solids and liquid in the form of a slurry.

Disc separators with fixed or suspended rotating drums have been disclosed.

German patent application publication DE 19846535a1 discloses a centrifuge with a suspended bowl in which a soft pocket is placed below the bowl to collect solids. The container of the centrifuge is designed cylindrically in the centrifugal separation area of the bowl.

This centrifuge has the disadvantage that the centrifuged solids may remain suspended in the centrifugal separation zone and, as a result, the solids cannot be collected centrally.

It is also known that in the case of a solid paste with good fluidity, by opening the drum very briefly, a so-called separation of the sludge can be achieved, which allows a higher solids content of the discharged paste.

In recent years, attempts have been made to produce highly concentrated pastes by withdrawing the liquid portion of the drum before it is emptied and to discharge the highly concentrated paste through a larger gap than has hitherto been common.

Such a device determines that the paste discharge is performed in a horizontal direction on an outer circumference under centrifugal acceleration, and the discharged paste can be collected in an annular container. However, it is desirable that the paste be collected in a container located below the drum. This is best possible in centrifuge embodiments with a suspended bowl. The paste must then be diverted from the horizontal direction downwardly into the container.

Disclosure of Invention

The invention relates to a device comprising a paste guide ring and a paste container which can be connected to or disconnected from the guide ring and which can receive paste discharged by multiple drum discharge. The guide ring is designed to enable steering with as little product depletion as possible.

To this end, the invention provides a paste guide ring for an automatic discharge centrifuge and having an annular wall, the angle of orientation α of the tangent to the guide ring wall opposite the discharge slot of the centrifuge, viewed over the entire opening width of the discharge slot, being between 3 ° and 60 ° to the horizontal, characterized in that the guide ring is designed with a surface cooling.

The solids thrown out of the discharge slot can thus be diverted with great care and low shear into the collection container of the centrifuge.

A special guide ring is characterized in that the inner contour of the retaining wall, viewed in any longitudinal section of the guide ring, is circular or parabolic just below the retaining surface. In this way, the diversion is accomplished with further product protection and the shear forces are further reduced.

In a preferred embodiment, the baffle wall has a curved inner contour, viewed in geometric longitudinal section, in the region below the discharge slot, with a radius of curvature of > 20mm, preferably 30mm to 50 mm. The curved wall surface can also be constructed according to a curve whose radius varies over the course.

In a particularly preferred embodiment, the baffle wall has an angle of orientation γ of 3 ° to 30 °, preferably 5 ° to 15 °, to the horizontal in the region above the width of the opening of the discharge slot.

A preferred variant of the guide ring is characterized in that, viewed in a longitudinal section of the geometric shape, a tangent to the inner contour of the stop face in the region below the deflection contour of the guide ring has an angle of orientation β of up to 30 ° and preferably 5 ° to 15 ° relative to the vertical. In this case, the vertical line is parallel to the axis of rotation of the drum. In this way, it is particularly advantageous to direct the thrown-off product towards the center of the collecting container.

In a preferred variant, the paste guide ring has a profiled edge at the lower end, which is optionally undercut.

In particular, the guide ring is integrated with a collecting container or is detachably connected with the collecting container of the centrifuge.

The surface cooling is, for example, a double wall on the outer circumference of the guide ring, through which a heat exchange medium can flow.

In a preferred embodiment, the product-contacting surface of the guide ring has a sliding coating, in particular made of PTFE or a metal alloy.

In a further preferred variant, the guide ring has one or more nozzles for spraying liquid nitrogen.

In particular, the nozzles are distributed over the circumference of the guide ring below the baffle surface, which corresponds to the opening width of the discharge slot.

The invention also provides an automatic discharge centrifuge for the processing of highly concentrated pastes, comprising at least one or coolable housing, a feed line for the suspension, a discharge line for the clarified liquid, a suspension drum which is connected to the upper drive and has two or more discharge slots, a collection container which can be separated from the housing if appropriate, and a paste discharge device, wherein the centrifuge has a guide ring according to the invention.

The collecting container is cylindrical or tapers conically downwards. The conical constriction of the collection vessel facilitates the discharge of e.g. frozen dessert from the vessel. The upper edge of the vessel is especially designed to produce a swirl-less flow below the best obtained guide ring profile edge.

Also, in a preferred embodiment, the product-contacting surface of the collecting container has a sliding coating, in particular made of PTFE or a metal alloy.

It is particularly preferred that a pocket made of flexible material is inserted into the collecting container, which pocket can be fixed to the tube wall, in particular by means of underpressure. Suitable materials for the pockets are all film plastics, in particular polypropylene, polyethylene or polyvinyl chloride.

In a further preferred embodiment of the centrifuge, the collecting container is designed with a temperature control device, in particular with a surface cooling.

The collecting container also preferably additionally has means for transport, in particular by means of a ground conveyor.

It is particularly preferred to configure the upper opening of the collecting container in the shape of an engaging flange. As a result, the collecting container can be closed, for example, by a lid and designed such that it can be connected to further process equipment, in particular a dissolving tank.

For use in the field of biotechnology, for example for the separation of pastes or for the clarification of liquids in human plasma separation, the collection container is designed such that the container surface can be cooled.

In order to be able to intensify the cooling effect, one or more nozzles can be installed, through which liquid nitrogen can be fed into the gas space in the vicinity of the rotating drum, in order to suppress the discharge space from being heated by air friction.

A disc separator is disclosed which can be cleaned automatically by a localized cleaning. For this purpose, the separator is flushed with different cleaning liquids under certain special operating conditions. A dedicated CIP nozzle may be installed to assist in cleaning. In designing the components and the sealing of the components to one another, care is taken that they are readily accessible for cleaning.

The container may be made of a metallic or non-metallic material. The containers may or may not be separately housed in a rack that is transported or stacked by ground transport carts.

The container may be equipped with a lid or with an automatic opening slide and is suitable for filling the dissolving tank.

Like the guide ring, the container may also be provided with the ability to cool the surface of the container, for example for use in bioengineering.

Drawings

The present invention will now be described in detail by way of example with reference to the accompanying drawings. Wherein:

fig. 1 shows a longitudinal section through an improved centrifuge 1;

fig. 2 shows an enlarged part of the longitudinal section shown in fig. 1.

Detailed Description

A centrifugal separation drum 14 discharges the biological paste present during the separation of human plasma at a drum speed of 7000l/min and with deflection by a paste guide ring 4, wherein the centrifugal separation drum 14 has an outer diameter of 468 mm. The centrifuge 1 has a drive 13 for driving the bowl 14 and having a plasma feed line 11. The drum 14 is suspended in a separable lower part of the centrifuge 1, the centrifuge 1 comprising a housing sleeve 10 with a feed line 19 and a discharge line 22 for the cooling liquid and a feed line 9 for the liquid nitrogen, a guide ring 4 and a collecting vessel 7. The collecting container has a cooling jacket 16 with an inlet line 20 and an outlet line 21 and a welded-on transport clamp 18. In addition, the drum 14 has an outlet 12 for clarified liquid. Fig. 2 shows the guide ring 4 in detail. The walls 2 of the paste guide ring 4 in the region of the discharge gap 3 form an angle α of 15 ° with the horizontal (see fig. 2). The angle γ above the opening width of the discharge slot 3 is also inclined by 15 ° with respect to the horizontal, so that the stop face 8 itself and the region above it are aligned in the plane of projection. Below this stop surface, the discharged paste is deflected to the container bottom by a contour which, viewed in longitudinal section, is circular and has a radius of curvature r of 45 °. In order to move the discharged solids away from the vessel wall toward the center of the bottom, the adjacent faces 19 are inclined at an angle β of 10 ° to the vertical. The paste guide ring 5 has a contoured edge 6 at its lower end.

By this geometry, the paste deflection can be achieved almost completely. For example, after two discharges of the centrifuge drum, 98.3% of the discharged solids amount is located in the collection container 7 below the centrifuge drum, and only 1.7% remains on the surface of the guide ring. Further experiments with different biological pastes showed that after six discharges the amount of solids in the collection container reached 99.5% with only 0.5% of the solids being lost on the surface of the paste guiding ring.

Claims (20)

1. A paste guide ring for an automatic discharge centrifuge (1) and having an annular retaining wall (2), the positioning angle α of the tangent to the retaining wall (2) of the guide ring (4) opposite the discharge gap (3) of the centrifuge (1) being 3 ° to 60 ° to the horizontal across the entire opening width of the discharge gap (3), characterized in that the guide ring is designed with a surface cooling (8).

2. Guide ring according to claim 1, characterized in that the inner contour of the retaining wall (2) is circular or parabolic just below the retaining surface, viewed in any longitudinal section of the guide ring.

3. Guide ring according to claim 2, characterized in that the baffle wall (2) has a curved inner contour, viewed in geometrical longitudinal section, in the region below the discharge slot (3), with a bending radius > 20 mm.

4. The guide ring of claim 3, wherein the bend radius is 30mm to 50 mm.

5. Guide ring according to one of claims 1 to 4, characterized in that the baffle wall (2) has an orientation angle γ of 3 ° -30 ° relative to the horizontal in the region above the opening width of the discharge slot (3).

6. The guide ring of claim 5, wherein the orientation angle γ is between 5 ° and 15 °.

7. Guide ring according to one of claims 1 to 4, characterized in that, viewed in a longitudinal section of the geometric shape, the tangents to the inner contour of the stop face (5) in the region below the deflection contour of the guide ring have an angle of orientation β of up to 30 ° relative to the vertical.

8. The guide ring of claim 7, wherein the orientation angle β is 5 ° -15 °.

9. Guide ring according to one of claims 1 to 4, characterized in that the paste guide ring (4) has a profiled edge (6) at the lower end, which is undercut if necessary.

10. Guide ring according to one of claims 1 to 4, characterized in that the guide ring (4) is integrated with a collecting container or is detachably connected with a collecting container (7) of the centrifuge (1).

11. Guide ring according to one of claims 1 to 4, characterized in that the positioning angle α is 10 ° -30 °.

12. Guide ring according to one of claims 1 to 4, characterized in that the product-contacting surface of the guide ring has a sliding coating made of PTFE or a metal alloy.

13. Guide ring according to one of claims 1 to 4, characterized in that it has one or more nozzles (9) for spraying liquid nitrogen.

14. An automatic discharge centrifuge (1) for the processing of highly concentrated pastes, comprising at least one coolable housing (10), a feed line (11) for the suspension, a discharge line (12) for the clarified liquid, a suspension drum (14) which is connected to an upper drive (13) and has two or more discharge slots (3), and a collecting container (7), characterized in that the centrifuge (1) has a guide ring (4) as claimed in one of claims 1 to 13.

15. The centrifuge according to claim 14, characterized in that the collecting container (7) is cylindrical or conically tapering downwards.

16. The centrifuge according to claim 14 or 15, characterized in that the inner surface of the collecting container (7) which contacts the product has a sliding coating made of PTFE or a metal alloy.

17. A centrifuge according to claim 14 or 15, c h a r a c t e r i z e d in that a pocket (17) made of flexible material is introduced into the collecting container (7), which pocket can be fixed to the tube wall by means of underpressure.

18. The centrifuge as claimed in claim 14 or 15, characterized in that the collecting container (7) is designed with a temperature control device (16).

19. The centrifuge according to claim 14 or 15, characterized in that the collecting container (7) additionally has means for transport by means of a ground conveyor.

20. A centrifuge according to claim 14 or 15, c h a r a c t e r i z e d in that the upper opening of the collecting container (7) is shaped as a joint flange.