EP3040127A1

EP3040127A1 - Filter centrifuge

Info

Publication number: EP3040127A1
Application number: EP15192704.3A
Authority: EP
Inventors: Johannes Feller; Gunnar Grim
Original assignee: Andritz KMPT GmbH
Current assignee: Andritz KMPT GmbH
Priority date: 2014-12-23
Filing date: 2015-11-03
Publication date: 2016-07-06
Anticipated expiration: 2035-11-03
Also published as: JP6199946B2; JP2016117059A; ES2635046T3; DE102014119605A1; EP3040127B1

Abstract

A Filter centrifuge (1) for filtering solid from a solid-liquid-suspension may comprise: a filter drum (10) comprising a circumferential groove (19) which groove is formed in an inner surface (21) of the filter drum (10) and runs in circumferential direction of the filter drum (10); a filter cloth (30) which is insertable into the filter drum (10), forms, at least when inserted into the filter drum (10), a hollow cylindrical shape which shape defines an axial direction (X) and a radial direction (R) and which shape has circumferential edges at the axial ends (32) thereof, is configured to hold back the solid from the suspension to be filtered and to let the liquid of the suspension to be filtered pass therethrough, and comprises at at least one of the circumferential edges (32) a circumferential ribbon structure (34; 34'; 34"; 34'"; 34"") which is formed by at least two ribbon layers (36,38; 36',38';36",38"; 36"',38"',39; 36"") which at least substantially overlap each other in the radial direction and are attached to one another, wherein, with the filter cloth (30) inserted into the filter drum (10), the circumferential ribbon structure (34; 34'; 34"; 34'"; 34"") is received in the circumferential groove (19) of the filter drum (10); and a clamping ring (40) which is formed separately from the filter cloth (30), is formed closed and as one piece, is radially spring-elastically pliable, and is disposable inside of the filter drum (10) opposite to the circumferential groove (19) so as to press the circumferential ribbon structure (34; 34'; 34"; 34'"; 34""), received in the circumferential groove (1), radially outwardly against the filter drum (10) such that the filter cloth (30) thereby remains firmly held in the filter drum (10).

Description

Field of the Invention

The present invention relates to a filter centrifuge, such as a filter centrifuge for filtering solid from a solid-liquid-suspension, which filter centrifuge comprises a filter drum, a filter cloth comprising a circumferential ribbon structure, and a clamping ring which is formed separately therefrom, closed and in one piece and which presses the circumferential ribbon structure radially outwards against the filter drum such that the filter cloth thereby remains firmly held in the filter drum.

Background of the Invention

Filter centrifuges are, for example, used in the pharmaceutical industry, the foods industry and the chemical industry for processing pharmaceutical agents, foods or fine chemicals.
As a possible type of construction of a filter centrifuge, for example a discontinuous peeler centrifuge is known. It comprises a filter drum which is rotatably supported in a housing and to which a solid-liquid-suspension to be filtered is supplied by a suspension supply device protruding into the filter drum. Further, a solid discharge device additionally protrudes into the filter drum by means of which the filtered solid is discharged from the filter drum. In addition, the peeler centrifuge comprises a filter means, which is usually a filter cloth, at an inner wall of the filter drum, which filter means serves for separating the solid from the solid-liquid-suspension and is firmly held, in particular in such a way that it is not able to shift substantially, in the filter drum by, e.g., clamping means.
During operation, the solid-liquid-suspension to be filtered is fed to the rotating filter drum via the suspension supply device. Due to the rotation of the filter drum, the solid-liquid-suspension to be filtered is pushed radially outwards to the radially inner wall of the filter drum and therefore to the filter cloth. The liquid of the suspension penetrates the filter cloth as well as the solid matter depositing on the filter cloth and is discharged or rather centrifuged from the filter drum (e.g., by means of drainage bores or drainage channels). The solid remains as filter cake on the filter cloth and, when, for example, a required degree of separation of liquid and solid is obtained by centrifuging the liquid, the solid is finally discharged from the filter drum by means of the discharge device, for example by means of a peeling knife which peels off the filter cake.
As mentioned above, it is important for the function of such filter centrifuges that the filter cloth is attached firmly in the filter drum such that a generation of wrinkles or circumvention of the filter cloth by the solid due to a displacement of the filter cloth cannot occur in order to prevent damage to the filter cloth and loss of product as well as product contamination. In particular, the generation of wrinkles can lead to a destruction of the filter cloth by the peeling knife during discharge of the solid which can mean a longer down time, a re-cleaning, and replacement costs of the filter cloth.
It is likewise required that mounting of the filter cloth into the filter drum can be carried out easily and quickly by the operating personnel, preferably by a single person, and that the filter cloth as well as the corresponding clamping means are cost-efficient and are suitable for a maximized bandwidth of applications of the filter centrifuges, in particular for as many types of materials to be filtered as possible, such as solid-liquid-suspensions that contain solvents, in order to keep the number of different filter cloths and corresponding mounting means and thus also production costs and storage costs low.
Therefore, under the above requirements, there is a continuous demand for improving the mounting of the filter cloth in the drum by clamping means.

Summary of the invention

The invention provides a filter centrifuge in which a filter cloth can be mounted in the filter drum without tools and in few steps by a clamping means, which clamping means can be formed in such a manner that it is suitable for a plurality of applications of the filter centrifuge, and in which a firm mount of the filter cloth is given, whereby a displacement of the filter cloth in the filter drum is prevented and, simultaneously, a simple and quick installation is achieved and production costs and storage costs are kept low. Further, the clamping ring as well as the filter cloth can be manufactured from cost-efficient materials and in a simple manner, whereby the costs for the clamping means as well as the filter cloth can be kept low.
According to an aspect of the present invention, a filter centrifuge (e.g. a discontinuous (peeler) centrifuge, for example a centrifuge as described in the background of the invention) for filtering solid from a solid-liquid-suspension comprises: a filter drum comprising a circumferential groove, which groove is formed in an (radially) inner surface of the filter drum (e.g. a radially inner surface of a filter jacket of the filter drum) and runs (e.g. continuously circumferentially, for example all around or by full 360 degrees continuously circumferentially) in the circumferential direction of the filter drum; a filter cloth which is insertable into the filter drum, forms, at least when inserted into the filter drum, a hollow cylindrical shape which shape defines an axial direction and a radial direction and which shape has circumferential edges provided at axial ends thereof (e.g. a first circumferential edge at a first axial end and a second circumferential edge at a second axial end), is configured to hold back the solid from the suspension to be filtered and to allow the liquid of the suspension to be filtered to pass therethrough, and comprises, at at least one of the circumferential edges, a circumferential ribbon structure which is formed by at least two (e.g. exactly two, exactly three, exactly four, etc.) ribbon layers which at least substantially overlap each other in the radial direction and are attached to one another, wherein, with the filter cloth inserted into the filter drum, the circumferential ribbon structure is received in the circumferential groove of the filter drum; and a clamping ring which is formed separately (e.g. as a separate component) from the filter cloth, is formed closed and as one piece, is radially spring-elastically pliable, and is disposable inside of the filter drum opposite to the circumferential groove so as to press (e.g. spring-elastically clamp) the circumferential ribbon structure, which is received in the circumferential groove, radially outwardly against the filter drum so that the filter cloth thereby remains firmly held in the filter drum. The feature that the clamping ring is formed closed and as one piece means that the closed ring (shape) is provided as one (integral) piece. That is, the clamping ring is a non-detachably endless ring (i.e., is a ring which is endless in a non-detachable manner) such that its ring shape cannot be non-destructively (re)opened. That is, in order to (re)open the ring shape, a portion of the clamping ring needs to be destroyed (e.g., by mechanically or thermally cutting the ring or by mechanically overstressing and breaking the connection by means of which the endless ring shape is formed). Correspondingly, the clamping ring is free of any detachable fasteners and, hence, has to be elastically deformed radially and inwardly in order to be inserted into the drum. According to an embodiment, the ring is formed as one monolithically integral piece. Further, the circumferential ribbon structure does, e.g., not include any supporting sieve (structure) and/or supporting strainer, on which, e.g., otherwise the filter cloth may rest and/or may be supported. In other words, the circumferential ribbon structure omits and/or is free of any such supporting sieve (structure) or supporting strainer. According to an embodiment, the circumferential ribbon structure and/or that portion of the filter cloth which is immediately adjacent to the circumferential ribbon structure are/is of such flexibility that they/it can be radially and outwardly deformed in order to allow the circumferential ribbon structure to be pressed into the circumferential groove by the clamping ring. The said flexibility may be such that low pressures acting on the circumferential ribbon structure in a radial outward direction, such as lower than 5 bar or lower than 2 bar, are sufficient to provide the afore described deformation.
The radial pressing force of the clamping ring is based on its radial spring elasticity according to which the clamping ring is, for example, pressed somewhat radially inwardly for being inserted into the filter drum, wherein, when it is disposed in the filter drum as described above, it then springs back into its original shape due to its elastic restoring force so as to press the circumferential ribbon structure received in the circumferential groove radially outwards against the filter drum.
The circumferential ribbon structure is, for example, formed by the same material, e.g., by the same woven fabric material, as the filter cloth. However, the ribbon layers of the circumferential ribbon structure may be respectively formed by materials which are different from the filter cloth and/or different from each other.
The circumferential ribbon structure is, e.g., stitched or welded or adhered to the one circumferential edge of the filter cloth. For example, the ribbon layers of the circumferential ribbon structure may be stitched and/or welded and/or adhered together and then be commonly stitched and/or welded and/or adhered to the filter cloth as a package. However, the ribbon layers of the circumferential ribbon structure may also be stitched and/or welded and/or adhered to the filter cloth one after another.
The ribbon layers of the circumferential ribbon structure comprise, e.g., widths in the axial direction, which are different from each other, wherein, for example, the ribbon layer that is in the radial direction further outside comprises (e.g., depending on the cross-sectional shape of the circumferential groove) a smaller or greater width in the axial direction than the ribbon layer that is in the radial direction further inside. Further, the ribbon layers have, for example, the same thickness when viewed in the radial direction and are, for example, as thick as the filter cloth or comprise, for example, (e.g., depending on the cross-sectional shape of the circumferential groove) thicknesses in the radial direction which are different from the filter cloth and/or from each other. Further, the volume of the circumferential ribbon structure is, for example, at least substantially equal to the volume of the circumferential groove, and the circumferential ribbon structure, for example, substantially completely fills out the circumferential groove. Thus, the circumferential ribbon structure can be adapted to the shape of the corresponding circumferential groove of the filter drum so that a fit, providing as reduced as possible dead spot and being as accurate and/or form-fitting as possible, of the circumferential ribbon structure in the corresponding circumferential groove can be achieved.
A ribbon layer of the circumferential ribbon structure, optionally the ribbon layer that is the innermost in the radial direction, is, for example, formed by the filter cloth, optionally by the one circumferential edge of the filter cloth.
At least two ribbon layers of the circumferential ribbon structure, optionally all ribbon layers of the circumferential ribbon structure, are, for example, formed by the filter cloth through folding back the circumferential edge of the filter cloth, optionally through hemming the circumferential edge of the filter cloth.
The ribbon layer which is the innermost in radial direction comprises a flap portion or tongue portion which runs out of the circumferential groove towards the filter cloth and is overlapped with the filter cloth and by means of which the circumferential ribbon structure is fixed to the filter cloth.
The filter cloth is made, for example, from a woven fabric material, optionally from a plastic woven fabric material. Further, the filter cloth is, for example, a filter cloth which is circumferentially closed and formed as one piece. The latter means that the closed circumferential shape is formed as one piece.
The clamping ring is, e.g., a clamping ring which is made of metal, optionally of spring steel. The clamping ring is, for example, made monolithically or through bending a flat strip into a ring shape and through welding the abutting longitudinal ends edge to edge. The clamping ring comprise, for example, an (outer) diameter which is at least substantially equal to or slightly smaller than the diameter of the circumferential groove of the filter drum such that, with a circumferential ribbon structure arranged between the circumferential groove and the clamping ring, a radially acting pressing force is applied to the circumferential ribbon structure by an outer side of the clamping ring.

Short Description of the Drawings

Fig. 1 is a schematic cross-sectional view of a filter centrifuge according to various embodiments of the present invention.
Fig. 2 is an enlarged view of an area A of Fig.1 which illustrates a first embodiment of the present invention.
Fig. 3 is an enlarged view of an area A of Fig.1 which illustrates a second embodiment of the present invention.
Fig. 4 is an enlarged view of an area A of Fig.1 which illustrates a third embodiment of the present invention.
Fig. 5 is an enlarged view of an area A of Fig.1 which illustrates a fourth embodiment of the present invention.
Fig. 6 is an enlarged view of an area A of Fig.1 which illustrates a fifth embodiment of the present invention.

In the figures, the same reference signs are used for the same or similar components.

Detailed Description

The invention will be described in detail by means of embodiments with reference to the drawings.
As shown in Fig. 1 and Fig. 6, a filter centrifuge 1 for filtering solid from a solid-liquid-suspension according to various embodiments of the present invention comprises a filter drum 10, a filter cloth 30 and a clamping ring 40.
The filter drum 10 according to various embodiments of the present invention comprises a drum jacket 11 which has a hollow cylindrical shape, a first drum bottom 13 which is connected therewith at an axial end of the drum jacket 11 (e.g., in Fig. 1, the right end of the drum jacket 11) and which closes this end of the drum jacket 11, and a second drum bottom (e.g. a drum collar) 15 which is connected therewith at the other (e.g. the opposite) axial end of the drum jacket 11 (e.g., in Fig. 1, the left end of the drum jacket 11) and which comprises a central opening 17.
Further, the filter drum 10 according to various embodiments of the present invention comprises a (e.g. first) circumferential groove 19 which is formed in a (radially) inner surface 21 of the filter drum 10 at a first axial side 12 of the filter drum 10, optionally in a (radially) inner surface of the drum jacket 11 at a first axial side of the drum jacket 11. Further, the filter drum 10 comprises, for example, a second circumferential groove 20 which is formed in the (radially) inner surface 21 of the filter drum 10 at a second axial side 14, which is opposite to the first axial side of the filter drum, of the filter drum 10, optionally in the (radially) inner surface of the drum jacket 11 at a second axial side of the drum jacket 11, which second axial side is opposite to the first axial side 12 of the drum jacket 11. Further, the circumferential groove 19 runs in the circumferential direction of the filter drum 10, optionally in the circumferential direction of the drum jacket 11.The circumferential groove 20 also runs in the circumferential direction of the filter drum 10, optionally in the circumferential direction of the drum jacket 11.
The filter cloth 30 according to various embodiments of the present invention is insertable into the filter drum through the opening 17 (e.g. with a centrifuge cover 43, to be described later, being open).The filter cloth 30 has, at least when inserted into the filter drum 10, a hollow cylindrical shape which defines an axial direction X and a radial direction R (see Figs. 2 to 6). For example, the filter cloth 30 may be formed as a circumferentially closed filter cloth (e.g. by stitching both longitudinal ends of a filter cloth sheet edge to edge) which is insertable into the filter drum 10 and forms the hollow cylindrical shape. Otherwise, the filter cloth 30 may also be formed as a (open or non-closed) filter cloth sheet which is inserted into the filter drum 10 and forms the hollow cylindrical shape in the filter drum 10 by overlapping both longitudinal ends of the filter cloth sheet therein. In addition, the filter cloth 30 comprises circumferential edges present at axial ends thereof, e.g. a first circumferential edge at a first axial end and a second circumferential edge at a second axial end of the filter cloth 30. In Figures 2 to 6, only the one circumferential edge 32 at the axial end, that is on the left side with reference to Fig. 1, of the filter cloth 30 is exemplarily shown.
The filter cloth 30 is further configured to retain the solid from the suspension to be filtered and to allow the liquid of the suspension to be filtered to pass therethrough. For this, the filter cloth 30 is presently made of a woven fabric material, e.g. of a plastic woven fabric material, e.g. of a polypropylene woven fabric material, which has a predetermined mesh size (or aperture width) for the filtration, is, however, not limited thereto. For example, the filter cloth 30 may also be made from a felt material, or the filter cloth 30 may be a knitted filter cloth. Basically, the filtration characteristics and the material characteristics of the filter cloth may be selected suitably for the intended application and use of the centrifuge.
Further, the filter cloth 30 according to various embodiments of the present invention comprises at at least one (e.g. at only one or at both) of the circumferential edges a circumferential ribbon structure 34. The circumferential ribbon structure 34 is formed by at least two (e.g. exactly two, exactly three, exactly four, etc.) ribbon layers which at least substantially overlap each other in the radial direction R and are attached to one another (e.g. stitched to each other and/or welded to each other). With the filter cloth 30 inserted into the filter drum 10, the circumferential ribbon structure 34 is received in the circumferential groove 19 of the filter drum 10. The ribbon layers may have widths which are different from each other in the axial direction X, wherein, for example, the ribbon layer that is in the radial direction R further outside may have (e.g. depending on the cross-sectional shape of the circumferential groove) a smaller or a greater width in the axial direction X than the ribbon layer which is in the radial direction R further inside. The ribbon layers may further be equally thick when seen in the radial direction R and, e.g., be as thick as the filter cloth 30 or may (e.g. depending on the cross-sectional shape of the circumferential groove) have thicknesses in the radial direction R, which thicknesses are different from the filter cloth and/or from each other. Further, the volume of the circumferential ribbon structure is, for example, at least substantially equal to the volume of the circumferential groove, and the circumferential ribbon structure, for example, substantially completely fills out the circumferential groove. Thus, the circumferential ribbon structure 34 can be adapted to the shape of the corresponding circumferential groove of the filter drum 10 such that a fit, having as reduced as possible dead spot and being as accurate and/or form-fitting as possible, of the circumferential ribbon structure 34 in the corresponding groove can be achieved.
In the first embodiment, shown in Fig. 2, of the present invention, the circumferential ribbon structure 34 is formed by two ribbon layers 36 and 38 which are disposed one upon the other. Further, the circumferential ribbon structure 34 in Fig. 2 is stitched to the one circumferential edge 32 of the filter cloth 30. For example, the two ribbon layers 36 and 38 may be stitched together and may then be commonly stitched to the filter cloth 30 as a package. However, the two ribbon layers 36 and 38 may also be successively stitched to the filter cloth 30. However, the circumferential ribbon structure 34 of the first embodiment may also be additionally or alternatively attached to the circumferential edge 32 of the filter cloth 30 in a different manner, such as by welding and/or adhering. In the first embodiment of the present invention, the circumferential ribbon structure 34 is (and/or the ribbon layers 36 and 38 of the circumferential ribbon structure 34 are) made from the same woven fabric material as the filter cloth 30. This has, among others, the advantage that the durability of the circumferential ribbon structure is at least substantially the same as that of the filter cloth 30, whereby an early wear of the circumferential ribbon structure 34 in comparison to the filter cloth 30 and thus a possible damage of the filter cloth 30 due to a defective mounting in the filter drum 10 may be prevented.
In the second embodiment, shown in Fig. 3, of the present invention, the circumferential ribbon structure 34' according to the second embodiment is formed by two ribbon layers 36' and 38' (e.g. a first ribbon layer 36' and a second ribbon layer 38') which are disposed one upon the other. In the second embodiment of the invention, the two ribbon layers 36' and 38' may also be attached to the filter cloth 30 by stitching, welding and/or adhering as already described above for the first embodiment of the invention. The two ribbon layers 36' and 38' of the second embodiment of the present invention are made from a material that is different from the filter cloth 30. Further, the two ribbon layers 36' and 38' of the second embodiment may be made from materials that are different from the filter cloth 30 and also different from each other, e.g. from a plastic material, a rubber material, a felt material, etc.. For example, the filter cloth 30 may be made from a woven fabric material, whereas the ribbon layers 36' and 38' are respectively not made from a woven fabric material, but are made from, e.g., an integrally and/or monolithically formed strip of, for example, plastic (e.g. a flat plastic strip), rubber, felt, etc..
In the third embodiment, shown in Fig. 4, of the present invention, a (e.g. first) ribbon layer 36" of the two ribbon layers of the circumferential ribbon structure 34" according to the third embodiment, optionally the layer that is the innermost in the radial direction R, is formed by the filter cloth 30, optionally by the circumferential edge 32 of the filter cloth 30. The second ribbon layer 38" may be attached to the filter cloth 30 through, for example, stitching, welding and/or adhering thereto as described before. Here, the second ribbon layer 38" is made from the same woven fabric material as the filter cloth 30 which results among other things in the advantage, which was described above for the first embodiment, of the same durability of the circumferential ribbon structure 34" and the filter cloth 30. However, the second ribbon layer 38" may also be made from a material which is different from the filter cloth 30, e.g. a plastic material, a rubber material, a felt material, etc.. For example, the filter cloth 30 may be made from a woven fabric material, whereas the second ribbon layer 38" is respectively not made from a woven fabric material, but made from, e.g., an integrally and/or monolithically formed strip of plastic (e.g. a flat plastic strip) or rubber.
In the fourth embodiment, shown in Fig. 5, of the present invention, the circumferential ribbon structure 34"' is formed by three ribbon layers 36"', 38'" and 39, wherein the ribbon layer 39 that is the innermost in radial direction R comprises a flap portion 39' which runs out of the circumferential groove towards the filter cloth 30, and which is overlapped with the filter cloth 30, and by means of which the circumferential ribbon structure 34'" is attached (e.g. stitched and/or welded and/or adhered) to the filter cloth 30. However, the circumferential ribbon structure 34'" may also comprise only two ribbon layers, namely the ribbon layer 39 that is the innermost in radial direction R and that has the flap portion 39', and a second ribbon layer 36. The ribbon layers 36"', 38"' and 39 may be respectively formed from the same material as the filter cloth 30 or may be respectively formed from materials which are different from the filter cloth and/or from each other. For example, the ribbon layer 39 may be formed from the same woven fabric material as the filter cloth 30, whereas the ribbon layers 36'" and 38'" may be formed from a material that is different therefrom.
In the fifth embodiment of the present invention, as exemplary shown in Fig. 6, at least two (e.g., exactly two, exactly three, exactly four, etc.) ribbon layers of the circumferential ribbon structure 34"" are formed by the filter cloth 30 through folding back, optionally hemming, the circumferential edge 32. For example, all ribbon layers 36"" of the circumferential ribbon structure 34"" may be formed by the filter cloth 30, as it is the case in Fig. 6. However, only a certain number (e.g., exactly two, exactly three, exactly four, etc.) of the ribbon layers may be formed by the filter cloth 30 and further ribbon layers may be attached to the ribbon layers formed by the filter cloth 30. The circumferential ribbon structure 34"", shown in Fig. 6, according to the fifth embodiment of the present invention, in which all ribbon layers 36"" are formed by the filter cloth 30, also has the above described advantage that the circumferential ribbon structure has the same durability as the filter cloth.
The clamping ring 40 according to various embodiments of the present invention is formed separately from the filter cloth 30. In case of, for example, wear of the clamping ring 40, it is hereby achieved that only the clamping ring needs to be replaced cost-efficiently and that the filter cloth 30 can be continued to be used. Moreover, the clamping ring 40 is closed as well as formed as one piece (That is, the clamping ring is made in the form of an endless ring, i.e. such that its ring shape cannot be non-destructively (re)opened; i.e., in order to (re)open the ring shape, a portion of the clamping ring needs to be destroyed (e.g., by mechanically or thermally cutting the ring or by mechanically overstressing and breaking the connection by means of which the endless ring shape is formed)) and is disposable inside the filter drum 10 opposite to the circumferential groove 19 in order to press the circumferential ribbon structure 34, 34', 34", 34"' and 34"", which is received in the circumferential groove, radially outwardly against the filter drum 10 such that the filter cloth 30 thereby remains firmly held in the filter drum 10. For this, the clamping ring 40 comprises, for example, a(n) (outer) diameter which is at least substantially equal to or slightly smaller than the diameter of the circumferential groove 19 of the filter drum such that, with the circumferential ribbon structure 34, 34', 34", 34'" and 34"" arranged between the circumferential groove 19 and the clamping ring 40, a radially acting pressing force is applied to the circumferential ribbon structure 34, 34', 34", 34'" and 34"" by an outer side 41 of the clamping ring 40. Further, the clamping ring 40 is radially spring-elastically pliable so as to be insertable into the filter drum 10 by being radially and inwardly pressed, and so as to spring back to its original shape when it is inserted into the filter drum 10. Since the described clamping ring 40 does not require any special tool for mounting the same in the filter 10 and may be mounted and dismounted manually in a simple manner with a few simple steps by a single person, the manufacturing costs and maintenance costs as well as the down time of the filter centrifuge 1 may be reduced.
The clamping ring 40 according to various embodiments of the present invention may be a clamping ring formed from metal, optionally from spring steel. Further, the clamping ring may be manufactured monolithically (e.g. may be cast as an endless ring in a single mould) or by bending a flat (metal) strip into a ring shape and by welding the abutting longitudinal ends edge to edge (i.e., the ring shape cannot be (re)opened in a nondestructive manner). The ends of the said flat strip may also overlap and may be welded or riveted or otherwise fixed to each other in a non-detachable manner. It is, however, also possible that the clamping ring is made from a material that is different from metal, e.g. from plastic, or from a combination of materials. By using a clamping ring made from metal, it can be manufactured in a cost-efficient manner. Further, a clamping ring made from metal is suitable for a plurality of applications of the filter centrifuge, in particular in the pharmaceutical industry, and offers a long life span and reusability.
The filter centrifuge 1 according to various embodiments of the present invention may, as shown in Fig. 1, further comprises a centrifuge cover 43 which is pivotably connected to a machine frame 45 or a machine housing in order to be opened. At the centrifuge cover 43, there are attached a suspension supply device 55 for supplying the solid-liquid-suspension to the filter drum 10 as well as a solid discharge device 50 for discharging the solid from the filter drum 10. In the closed-condition of the centrifuge cover 43, the centrifuge cover 43 closes the opening 17 of the filter drum 10 in a sealed manner, wherein the suspension supply device 55 and the solid discharge device 50 protrude into the filter drum 10, and surrounds the filter drum 10 together with the machine frame 45 such that the filter drum 10 is disposed in a room 47 which is formed in a sealed manner between the centrifuge cover 43 and the machine frame 45. Further, a liquid discharge device 57 which is in connection with the room 47 is provided in the machine frame 45 at the level of a lowest point of the room 47. The filter drum 10 is connected unilaterally to a drive shaft 60 and is attached to the machine frame 45 by the drive shaft 60 in an overhung manner. The filter drum 10 is driven by torque which is transmitted from a drive device 65, e.g. an electric drive, via a transmission device 70, e.g. a belt drive as shown in Fig. 1 or a chain drive or a gear drive, to the drive shaft 60. However, the drive shaft 60 may also be connected to the drive device 65 via a clutch or be integrally formed with the output shaft of the drive device 65.
The function of the filter centrifuge shown in Fig. 1 is as follows. The solid-liquid-suspension to be filtered is supplied to the filter drum 10 by means of the suspension supply device 55. The filter drum 10 is rotated by the drive device 65, whereby the solid-liquid-suspension is pushed towards the inner surface 21 of the filter drum 10. The liquid in the solid-liquid-suspension is able to penetrate the filter cloth 30, which is attached to the inner surface 21, and the filter drum 10 (e.g. by means of bores in the filter drum 10) and can therefore be centrifuged from the filter drum 10 into the room 47 to the centrifuge cover (e.g. an inner wall of the centrifuge cover) 43 and to the machine frame 45. The liquid is finally discharged from the room 47 by means of the liquid discharge device 57. The solid in the solid-liquid-suspension is retained by the filter cloth 30 and is separated from the solid-liquid-suspension in this way. Finally, when reaching a sufficient ejection of the liquid, the solid present at the filter cloth 30 as a filter cake is removed from the filter cloth 30 by means of the solid discharge device 50, e.g., by peeling the solid from the filter cloth 30 through the solid discharge device 50 (e.g. by means of a peeling knife provided at the solid discharged device 50) by rotating the filter drum 10 in a controlled manner, and is discharged from the filter drum 10 by means of the solid discharge device 50.

Claims

Filter centrifuge (1) for filtering solid from a solid-liquid-suspension, comprising:
a filter drum (10) comprising a circumferential groove (19) which is formed in an inner surface (21) of the filter drum (10) and runs in circumferential direction of the filter drum (10);

a filter cloth (30) which
- is insertable into the filter drum (10),

- forms, at least when inserted into the filter drum (10), a hollow cylindrical shape which defines an axial direction (X) and a radial direction (R) and which has circumferential edges at the axial ends (32) thereof,

- is configured to retain the solid from the suspension to be filtered and to allow the liquid of the suspension to be filtered to pass therethrough, and

- comprises, at at least one of the circumferential edges (32), a circumferential ribbon structure (34; 34'; 34"; 34'"; 34"") which is formed by at least two ribbon layers (36,38; 36',38';36",38"; 36"',38"',39; 36"") which at least substantially overlap each other in the radial direction and are attached to one another, wherein, with the filter cloth (30) inserted into the filter drum (10), the circumferential ribbon structure (34; 34'; 34"; 34'"; 34"") is received in the circumferential groove (19) of the filter drum (10); and

a clamping ring (40) which
- is formed separately from the filter cloth (30),

- is formed closed and as one piece,

- is radially spring-elastically pliable, and

- is disposable inside of the filter drum (10) opposite to the circumferential groove (19) so as to press the circumferential ribbon structure (34; 34'; 34"; 34"'; 34""), received in the circumferential groove (1), radially outwardly against the filter drum (10) so that the filter cloth (30) thereby remains firmly held in the filter drum (10).
Filter centrifuge (1) according to claim 1, wherein the circumferential ribbon structure (34; 34'; 34"; 34'"; 34"") is formed by the same material as the filter cloth (30).
Filter centrifuge (1) according to claim 1 or 2, wherein the circumferential ribbon structure (34; 34'; 34"; 34'"; 34"") is stitched and/or welded and/or adhered to the one circumferential edge (32) of the filter cloth (30).
Filter centrifuge (1) according to any one of the preceding claims, wherein a ribbon layer (36") of the circumferential ribbon structure (34"), optionally the ribbon layer (36") that is the innermost in the radial direction (R), is formed by the filter cloth (30).
Filter centrifuge (1) according to any one of the preceding claims, wherein at least two ribbon layers (36"") of the circumferential ribbon structure (34""), optionally all ribbon layers (36"") of the circumferential ribbon structure (34""), are formed by the filter cloth (30) through folding back the circumferential edge (32) of the filter cloth (30), optionally through hemming the circumferential edge (32) of the filter cloth (30).
Filter centrifuge (1) according to any one of the claims 1 to 3, wherein the ribbon layer (39) that is the innermost in radial direction (R) comprises a flap portion (39') which runs out of the circumferential groove (19) towards the filter cloth (30) and overlaps with the filter cloth (30), and by means of which the circumferential ribbon structure (34"') is fixed to the filter cloth (30).
Filter centrifuge (1) according to any one of the preceding claims, wherein the filter cloth (30) is made from a woven fabric material, optionally from a plastic woven fabric material.
Filter centrifuge (1) according to any one of the preceding claims, wherein the filter cloth (30) is a filter cloth (30) which is circumferentially closed and formed as one piece.
Filter centrifuge (1) according to any one of the preceding claims, wherein the clamping ring (40) is a clamping ring (40) which is made from metal, optionally from spring steel.
Filter centrifuge (1) according to any one of the preceding claims, wherein the clamping ring (40) is made monolithically or wherein the clamping ring (40) is made through bending a flat strip into a ring shape and through welding the abutting longitudinal ends edge to edge.
Filter centrifuge (1) according to any one of the preceding claims, wherein the volume of the circumferential ribbon structure (34; 34'; 34"; 34'"; 34"") is at least substantially equal to the volume of the circumferential groove (19), and the circumferential ribbon structure substantially completely fills out the circumferential groove (19).