Filtration device, filtration system and method of operating a filtration device

Abstract

A filtration device (1), a filtration system (100) and a method (200) for operating a filtration device are provided. In the disclosed filtration device (1), a stationary control disk unit (30) is provided, which is arranged stationary relative to a filter drum (10) and a sealing disk (20) and which comprises a control disk body (32) with a plurality of fluid control through holes (40), the fluid control through holes (40) comprising at least one initial cake formation through hole (42) and at least one main cake formation through hole (44), the at least one main cake formation through hole (42) and the at least one initial cake formation through hole (44) being separated from each other by a partition wall (34a), and a fluid connection unit (60) is also provided, which comprises a plurality of fluid lines connected with the plurality of fluid control through holes (40) of the control disk unit (30, 30'), wherein the plurality of fluid lines comprises a main filtrate line (64) connected to the at least one main cake formation through hole (44) and an initial filtrate line (62) separate from the main filtrate line (64) and connected to the at least one initial cake formation through hole (42), wherein the at least one main cake formation through hole (42) and the at least one initial cake formation through hole (44) are configured and arranged in the control disk body (32) to be connected to the one or more filtration cells (12), which are to be at least partially submerged among the plurality of filtration cells (12), via the plurality of sealing disk through holes (24) so as to receive and discharge filtrate from said one or more filtration cells (12) and to direct filtrate separately into the main filtrate line (64) and the initial filtrate line (62).

Description

[0001] 93609 1

[0002] FILTRATION DEVICE, FILTRATION SYSTEM AND METHOD OF OPERATING A FILTRATION DEVICE

[0003] Field

[0004] The invention relates to a filtration device, a filtration system and a method of operating a filtration device.

[0005] Background

[0006] Filtration devices are variously used for separating materials in industrial applications, such as in chemical and pharmaceutical industry, wastewater treatment, food processing and mining and mineral processing. For example, filtration devices using filter drums are used in such applications so as to implement continuous filtration processes to separate liquid components and solid components of a slurry from each other. Typically, the liquid components and solid components are at least partially separated into a filtrate (i.e. liquid components with a content of solid components) entering the filter drum and a cake of solid components retained by a filter cloth on an outer surface of the filter drum.

[0007] In many process applications, the amount of solid components entering the filter drum together with the liquid contents and thus the content of solid components in the filtrate forms an important parameter and criterion to be achieved and guaranteed by the filtration process.

[0008] Solid components may be introduced into and remain in the filtrate during the cake formation phase, in which a part of the filter drum enters submergence in the slurry and slurry and its liquid components and solid components are separated through the filter cloth covering the outer surface of the filter drum. Particles smaller than the pore diameter of the filter cloth may enter the filter drum together with the liquid components at the beginning of the cake formation phase, and thus the content of solid components in the filtrate may be high at the beginning of the cake formation phase. During the cake formation phase, as the cake forms on the filter cloth, the content of solid components in the filtrate reduces, since the cake itself then acts as a filter medium and not the filter cloth anymore. 93609 2

[0009] Filter cloths are available in various forms, various materials, various pore diameters and the like and may be selected depending on the actual process application and the process parameters to be achieved. However, selecting the optimal filter cloth for a particular application (e.g. process type, process parameters and process environment) may be difficult and require a significant amount of testing and experimentation. Therefore, considering budget constraints in industrial applications, it may not always be possible to find and select an optimal filter cloth, resulting in lower filtration efficiency and filtration quality. This may be particularly problematic in cases where the content of solid components in the filtrate is of high importance and must be at or below a guaranteed value during the filtration process. Further, with smaller particle size of the solid components in the slurry (e.g. D10 values below 10 microns), there are less and less filter cloths available for separating such small particles from the slurry.

[0010] Various attempts have been in the field to improve the above situation. For example, for further reducing the content of solid components and / or securing a desired content of solid components, a precoat technique may be applied, in which the filter cloth is pre-coated with an auxiliary filtration medium before entering the slurry so that the filtration process is mainly carried out by the auxiliary filtration medium already from the beginning of the cake formation phase. Such precoat techniques however require the use of the auxiliary filtration medium, increasing processing costs as such and further complicating the filtration device designs due to the necessary handling of the auxiliary filtration medium. Further, such precoat techniques may primarily be used in applications where the liquid components form the desired product, since the solid components may be contaminated by the auxiliary filtration medium.

[0011] Other attempts may involve only partial removal of the cake by a scraping device (e.g. a scraping knife) at the end of the filtration cycle such that a small layer of cake may remain on the filter cloth and act as the precoat layer. This approach however has the drawback of reduced throughput, which may require larger filter drums for achieving the same productivity. Further, removing the cake only partially leads to a continuous presence of the precoat layer on the filter cloth, which may result in recrystallization and hardening of the precoat layer and thus in faster deterioration of the filtration performance of the filter cloth. Hence, maintenance and replacement of the filter cloth may be more frequently required and may increase down time of the filtration device, resulting in higher costs and less productivity. 93609 3

[0012] In view of the above, there is a need for new techniques for improving filtration performance (in particular achieving lower content of solid components in the filtrate) while providing low costs and high productivity. Further, it may be also be desirable to provide new techniques, which may also be easily applied to already existing devices, i.e. to allow improvement of already existing devices by means of retrofitting.

[0013] Summary

[0014] By the invention, a filtration device, a filtration system and a method of operating a filtration device are provided, in which an initial cake and initial filtrate with relatively high content of solid components may be initially formed in a dedicated initial cake formation zone and a main cake may then be formed on the initial cake and a main filtrate may be produced by utilizing the initial cake as a precoat for the formation of the main cake in a dedicated main cake formation zone, wherein the main filtrate may have a lower content of solid components.

[0015] By the invention, filtration performance and product quality may thus be improved by utilizing the initial cake as the precoat, and the main filtrate with lower content of solid components may be used in subsequent filtrate processing stages. Further, by separately providing the initial filtrate with higher content of solid component and the main filtrate with lower content of solid components, product quality can be improved and more easily guaranteed. Further, the initial filtrate may be recirculated and reintroduced into the filtration process, thereby increasing the utilization of the liquid and solid components in the slurry and minimizing material loss and waste production. Accordingly, the present invention may provide for higher product quality while minimizing costs and providing or maintaining high productivity.

[0016] Further, since the present invention may allow replacement of some components of the filtration device with corresponding components in accordance with the present invention, without necessarily requiring substantial changes to the mode of operation I working principle of the filtration device, even already existing filtration devices may be retrofitted so as to implement the present invention and to realize the improvements achieved by the present invention.

[0017] To this end, the invention provides a filtration device, comprising: a slurry accommodating unit configured to accommodate a slurry comprising solid components 93609 4 and liquid components therein and to define a slurry level; a filter drum, said filter drum being configured to rotate at least partially submerged in the slurry and comprising a plurality of individual filtration cells, the filtration cells being configured to at least partially separate the solid and liquid components of the slurry by allowing the liquid components to enter the filtration cells in the filter drum as a filtrate and by retaining solid components of a predetermined size or greater on an outer surface of the filter drum so as to form a cake, wherein, upon rotation of the filter drum, one or more filtration cells among the plurality of filtration cells are configured to become at least partially submerged in the slurry when positioned at least partially below the slurry level; a sealing disk, which is connected with the filter drum so as to rotate together with the filter drum and which comprises a plurality of sealing disk through holes, each sealing disk through hole being in (e.g. fluid) connection with a respective filtration cell; a stationary control disk unit, which is arranged stationary relative to the filter drum and the sealing disk and which comprises a control disk body with a plurality of fluid control through holes, the fluid control through holes comprising at least one initial cake formation through hole and at least one main cake formation through hole, the at least one main cake formation through hole and the at least one initial cake formation through hole being separated from each other by at least one partition wall portion, which is formed in the control disk body; and a fluid connection unit, which comprises a plurality of fluid lines connected with the plurality of fluid control through holes of the control disk unit, wherein the plurality of fluid lines comprises a main filtrate line connected to the at least one main cake formation through hole and an initial filtrate line separate from the main filtrate line and connected to the at least one initial cake formation through hole, wherein the at least one main cake formation through hole and the at least one initial cake formation through hole are configured and arranged in the control disk body to be connected to the one or more filtration cells, which are to be at least partially submerged among the plurality of filtration cells, via the plurality of sealing disk through holes so as to receive and discharge filtrate from said one or more filtration cells and to direct filtrate separately into the main filtrate line and the initial filtrate line.

[0018] Optionally, the at least one partition wall portion may be formed with such a size and shape so as to not be able to completely seal adjacent ones of the plurality of sealing disk through holes from each other. In other words, the at least one partition wall portion may be formed with such a size and shape so as not be able to pressure-safely separate the fluid control through holes of the control disk unit, between which the 93609 5 partition wall portion is arranged in the control disk unit. For example, the at least one partition wall portion may be formed with such a size and shape so that the at least one main cake formation through hole and the at least one initial cake formation through hole may be subjected to the same pressure level.

[0019] The at least one initial cake formation through hole may be formed in the control disk body in advance of the at least one main cake formation through hole, based on a rotation direction of the filter drum. In other words, when moving along the rotation direction of the filter drum, a respective sealing disk through hole may first establish a fluid connection with the at least one initial cake formation through hole and may thereafter (e.g. separated through the partition wall portion) establish a fluid connection with the at least one main cake formation through hole.

[0020] The control disk body may be divided into a plurality of sectors. Each sector may correspond to a process step performed during a filtration process of the filtration device. The plurality of sectors may comprise a cake formation sector, wherein said cake formation sector may comprise an initial cake formation zone for forming an initial cake on the filter drum and in which the at least one initial cake formation through hole is located, and a main cake formation zone for forming a main cake on the initial cake and in which the at least one main cake formation through hole is located.

[0021] The cake formation sector may comprise a predetermined circumferential point of the control disk body, wherein the initial main cake formation zone may form, based on a rotation direction of the filter drum, a first angular range (e.g. a first angle) before the predetermined circumferential point and wherein the initial main cake formation zone may form, based on a rotation direction of the filter drum, a second angular range (e.g. a second angle) after the predetermined circumferential point. The at least one initial cake formation through hole may be formed in the control disk body in the first angular range, and the at least one main cake formation through hole may be formed in the control disk body in the second angular range. Optionally, each of the first angular range and the second angular range includes a range of 0 degree to 90 degree. Further optionally, the first angular range and the second angular range may have the same size or may have different sizes from each other.

[0022] The predetermined circumferential point of the control disk body may be a lowermost point of the control disk body. Said lowermost point of the control disk body 93609 6 may correspond to the lowermost submergence point of the filter drum, i.e. the lowermost point, submerged in the slurry, of the filter drum.

[0023] The at least one main cake formation through hole and the at least one initial cake formation through hole may be formed immediately adjacent to each other in the control disk body, only separated by the at least one partition wall portion formed in the control disk body. The at least one main cake formation through hole may include a plurality of main cake formation through holes, the individual main cake formation through holes being separated from each other by corresponding partition wall portions.

[0024] The at least one main cake formation through hole may extend in a curved shape (e.g. an arc-shape, which may for example be centered on the center point of the control disk body) from the at least one partition wall portion in the same direction as the rotation direction of the filter drum. The at least one initial cake formation through hole may extend in a curved shape (e.g. an arc-shape, which may for example be centered on the center point of the control disk body) from the at least one partition wall portion in the direction opposite to the rotation direction of the filter drum. The at least one main cake formation through hole and the initial cake formation through hole may have identical widths in circumferential direction or may have different widths in circumferential direction. The width in circumferential direction of the at least one initial cake formation through hole may be proportion (or fraction) of the at least one main cake formation through hole, e.g. may be in the range of 0.8 to 0.1 , in particular 0.5 to 0.2, of the width of the at least one main cake formation through hole. The “width in circumferential direction” of a through hole may refer to an angular range covered by the respective through hole (e.g. when viewed along an axis through the center point of the control disk body).

[0025] The at least one partition wall portion may extend substantially radially along a line connecting the center point of the control disk body and the predetermined circumferential point of the control disk body. The partition wall portion may for example have a trapezoidal shape, said trapezoidal shape tapering along the radial direction toward the center point of the control disk body. The partition wall portion may however also have other shapes.

[0026] The at least one partition wall portion of the control disk body may have a width in circumferential direction, which is smaller than a width in circumferential direction of one of the plurality of sealing disk through holes. The “width in 93609 7 circumferential direction” of a wall portion may refer to an angular range covered by the respective wall portion (e.g. partition wall portion or sealing wall portion) of the control disk body (e.g. when viewed along an axis through the center point of the control disk body).

[0027] The control disk body may further comprise at least one sealing wall portion, wherein the at least one sealing wall portion may have a width in circumferential direction, which is larger than the width in circumferential direction of the partition wall portion and larger than a width in circumferential direction of one of the plurality of sealing disk through holes. The at least one sealing wall portion may be formed with such a size and shape so as to be able to completely seal adjacent ones of the plurality of sealing disk through holes from each other. In other words, the at least one sealing wall portion may be formed with such a size and shape so as to be able to pressure- safely separate the fluid control through holes of the control disk unit, between which the sealing wall portion is arranged in the control disk unit. For example, the at least one sealing wall portion may be formed with such a size and shape so that the fluid control through holes of the control disk unit, between which the sealing wall portion is arranged in the control disk unit, may be subjected to different pressure levels.

[0028] The control disk body may further comprise a cake blow and / or bubbling through hole, which may be separated from the at least one initial cake formation through hole by said at least one sealing wall portion and may be configured to be connected a source of pressurized fluid with one or more filtration cells, which are to be at least partially submerged among the plurality of filtration cells, via the plurality of sealing disk through holes.

[0029] The filtrate directed into the main filtrate line may be a main filtrate, the filtrate directed into the initial filtrate line may be an initial filtrate. The initial filtrate may have a higher content of solid components than the main filtrate. The main cake and the initial cake may together form a final cake.

[0030] According to the invention, a filtration system is also provided, the filtration system comprising: a filtration device as described in this application, and a main filtrate accommodating and / or processing device, connected to the main filtrate line and configured to receive filtrate from the main filtrate line as a main filtrate, an initial filtrate accommodating and / or recirculating device, connected to the initial filtrate line and configured to receive filtrate from the initial filtrate line as an initial filtrate. 93609 8

[0031] The main filtrate accommodating and / or processing device may comprise a main filtrate transport line, which may be connected to or may be formed integrally with the main filtrate line so as to transport main filtrate to one or more subsequent main filtrate processing devices.

[0032] The main filtrate accommodating and / or processing device may comprise a main filtrate storage device, which may be connected to the main filtrate line and may store main filtrate received via the main filtrate line, and a main filtrate transport line, which may be connected to the main filtrate storage device and may be configured to transfer filtrate out from the main filtrate storage device to one or more subsequent main filtrate processing devices.

[0033] The initial filtrate accommodating and / or recirculating device may comprise a filtrate recirculation line, which may be connected to the filtration device and may be configured to recirculate the initial filtrate back into the slurry accommodating unit of filtration device.

[0034] The filtration system may further comprise a recirculation pump arranged in the filtrate recirculation line so as to transfer the initial filtrate back to the filtration device.

[0035] The initial filtrate accommodating and / or recirculating device may further comprise an initial filtrate storage device, which may be connected to the initial filtrate line and may store initial filtrate received via the initial filtrate line. An end of the filtrate recirculation line may be connected to the initial filtrate storage device and the other end of the filtrate recirculation line may be connected to the filtration device. Alternatively or additionally, an end of the filtrate recirculation line may branch off from the initial filtrate line upstream of the initial filtrate storage device and the other end of the filtrate recirculation line may be connected to the filtration device.

[0036] The initial filtrate line and the filtrate recirculation line may be connected to each other or formed integrally with each other.

[0037] The filtration system may further comprise a slurry feed vessel configured to store and supply slurry to the slurry accommodating unit of the filtration device. The initial filtrate accommodating and / or recirculating device may comprise a initial filtrate transport line, which may on the one hand (e.g. with one end portion) be connected to or formed integrally with the initial filtrate line and may on the other hand (e.g. with one 93609 9 end portion) be connected to the slurry feed vessel and / or to subsequent initial filtrate processing devices.

[0038] According to the invention, a method of operating a filtration device is provided. Optionally the method may be applied for operating a filtration device as described in this application. The method comprises: rotating a filter drum of the filtration device at least partially submerged in a slurry comprising solid components and liquid components, forming an initial cake on an outer surface of the filter drum and producing an initial filtrate from the liquid components by at least partially separating solid components and liquid components of the slurry in an initial cake formation zone of a cake formation sector among a plurality of sectors, each sector corresponding to a process step performed during a filtration process of the filtration device, forming a main cake on the initial cake and producing a main filtrate from the liquid components by at least partially separating solid components and liquid components of the slurry in a main cake formation zone of the cake formation sector, and transferring the main filtrate and the initial filtrate out of the filtration device separately from each other via a main filtrate line and an initial filtrate line.

[0039] The method may further comprise recirculating all or at least part of the initial filtrate back to the filtration device and into the slurry.

[0040] The method may further comprise storing all or at least part of the initial filtrate in an initial filtrate storage device.

[0041] The method may further comprise storing the main filtrate in a main filtrate storage device and / or transferring the main filtrate to one or more subsequent main filtrate processing devices.

[0042] The initial filtrate may have a higher content of solid components than the main filtrate. The initial cake and the main cake may form a final cake. The method may further comprises removing the final cake from the outer surface of the filter drum before repeating the step of forming an initial cake.

[0043] Brief Description of the Drawings

[0044] Fig. 1 is a drawing illustrating a configuration of relevant component of a filtration device according to an embodiment of the present invention. 93609 10

[0045] Fig. 2 is a drawing illustrating a filter drum and a stationary control disk unit of a filtration device according to an embodiment of the present invention from a frontal perspective.

[0046] Fig. 3 is a drawing illustrating a stationary control disk unit according to an embodiment of the present invention.

[0047] Fig. 4 is a drawing illustrating a stationary control disk unit according to another embodiment of the present invention.

[0048] Fig. 5 is a drawing illustrating a filtration system according to an embodiment of the present invention.

[0049] Fig. 6 is a drawing illustrating a filtration system according to another embodiment of the present invention.

[0050] Fig. 7 is a drawing illustrating a method of operating a filtration device according to an embodiment of the present invention.

[0051] It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various preferred features illustrative of the basic principles of the invention. The specific design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment.

[0052] In the figures, the same reference numbers refer to the same or equivalent components or parts of the present invention.

[0053] Detailed Description

[0054] The following description of diverse embodiments of the invention is not intended to limit the invention to any one of these embodiments or corresponding details. Throughout the drawings, same reference signs are used for same components. Terms like “first”, “second” etc. are intended to merely name a corresponding component, without defining a certain order or number of components so that, e.g., a component named as first component could also be a second component and vice versa. 93609 11

[0055] Referring to Figs. 1 to 4, a filtration device 1 according to an embodiment of the invention comprises at least one of a slurry accommodating unit (not explicitly shown), a filter drum 10, a sealing disk 20, stationary control disk unit 30 and fluid connection unit 60. The filtration device 1 may, e.g., be a pressure filtration device, a vacuum filtration device, a pressure / vacuum filtration device and / or a suction filtration device.

[0056] The slurry accommodating unit is configured to accommodate a slurry comprising solid components and liquid components therein. The slurry accommodating unit may for example be a trough, formed as part of (e.g. integrally with) a housing of the filtration device 1 or formed separately from and located within the housing. The slurry accommodating unit may accommodate the slurry so as to define a slurry level SL.

[0057] The filter drum 10 is configured to rotate at least partially submerged in the slurry. Specifically, the filter drum 10 may be configured to rotate in a rotation direction RD while being located so as to be partially submerged in the slurry, when the slurry is accommodated in the slurry accommodating unit so as to reach the slurry level SL. The filter drum 10 is configured to separate the solid components and liquid components of the slurry from each other. Specifically, the filter drum 10 comprises a plurality of individual filtration cells (e.g. individual filtration compartments) 12. The filtration cells 12 may be arranged adjacent to each other along a circumferential direction CD.

[0058] When the filter drum 10 rotates in the rotation direction RD while being partially submerged in the slurry, one or more filtration cells 12 among the plurality of filtration cells 12 may become at least partially submerged in the slurry when positioned at least partially below the slurry level SL. For example, during rotation of the filter drum 10 in the rotation direction RD, a respective filtration cell among the plurality of filtration cells 12 may be moved along the rotation direction RD below the slurry level and thus enter the slurry so as to finally become fully submerged in the slurry. Said respective filtration cell may then move along the rotation direction RD through the slurry to the lowermost submergence point LP and then again emerge from the slurry.

[0059] The filtration cells 12 are configured to at least partially separate the solid and liquid components of the slurry. For example, the filtration cells 12 may be configured to allow the liquid components to enter the filtration cells 12 in the filter drum 10 as a filtrate. On the other hand, filtration cells 12 may be configured to retain solid 93609 12 components of a predetermined size or greater on an outer surface 13 of the filter drum 10 so as to form a cake on the outer surface 13 of the filter drum 10. For example, the filter drum may comprise a filter cloth arranged along (e.g. defining) the outer surface 13 of the filter drum 10 and covering the filtration cells 12. The filtrate entering the filtration cells 12 in the filter drum 10 may include at least some of the solid components of the slurry, which may be able to pass through the outer surface 13 of the filter drum (e.g. the filter cloth), for example due to being smaller than the predetermined size. In other words, the filtrate entering and passing through the filtration cells 12 may include liquid components of the slurry and also include a content of solid components. Said content may be at least lower than the content of solid components in the slurry. Depending on the type of filtration device, vacuum applied to the filtration cells 12 or an overpressure within the filtration device housing may be used so as to perform the filtration process (e.g. to force the liquid components of the slurry to enter the filtration cells 12 in the filter drum). For example, once a filtration cell submerges in the slurry, vacuum may be applied to said filtration cell and a cake starts to form on the outer surface 13 of the filter drum 10 up to a point where said filtration cell emerges from the slurry. Such filtration principles of filtration devices using filter drums are known to the skilled person, and thus a further detailed description is omitted.

[0060] The sealing disk 20 comprises a sealing disk body 22. The sealing disk body 22 may be formed in a circular plate shape. The sealing disk body 22 of the sealing disk 20 is connected to the filter drum 10 so as to rotate together with the filter drum 10 in the rotation direction RD. The sealing disk body 22 of the sealing disk 20 comprises a plurality of sealing disk through holes 24. Each of the sealing disk through holes 24 is in connection (e.g. fluid connection) with a respective one among the plurality of filtration cells 12 of the filter drum. In more detail, each sealing disk through holes 24 may be connected to a respective one among the plurality of filtration cells 12 of the filter drum 10 via a respective filtration cell connection line 14 provided inside the filter drum 10. Accordingly, a fluid connection between the sealing disk through holes 24 and the filtration cells 12 of the filter drum 10 is established so as to allow fluid from the filtration cells 12 to flow via the filtration cell connection lines 14 towards the sealing disk through holes 24 and to be discharged through the sealing disk through holes 24.

[0061] The filtration device 1 according to an embodiment of the invention comprises the stationary control disk unit 30 and the fluid connection unit 60. The stationary control disk unit 30 and the fluid connection unit 60 may together form a fluid control head (also 93609 13 known in the art as a “valve”), which is in fluid connection with the sealing disk 20 and the filtration cells 12 of the filter drum 10.

[0062] Referring to Fig. 3, the stationary control disk unit 30 in an embodiment of the invention comprises at least one control disk body 32, which may be formed in a circular plate shape. The control disk body 32 includes a plurality of fluid control through holes 40, a plurality of partition wall portions 34a, 34b (commonly also referred to as “plurality of partition wall portions 34), a plurality of sealing wall portions 36a, 36b (commonly also referred to as “plurality of sealing wall portions 36”) and a central shaft hole 38. The stationary control disk unit 30 is arranged stationary relative to the filter drum 10 and the sealing disk 20.

[0063] The fluid control through holes 40 are formed in the control disk body 32 so as to extend in the circumferential direction CD. The fluid control through holes 40 are configured to become fluid connected to the sealing disk through holes 24 so as to receive the fluid discharged from the sealing disk through holes 24 and to distribute the fluid discharged from the sealing disk through holes 24 in a controlled manner to different fluid lines in the fluid connection unit 60. The fluid control through holes 40 may have fixed sizes and fixed cross-sectional shapes or may have variable sizes and variable cross-sectional shapes (e.g. variable by means of an opening adjustment mechanism, such as disclosed in e.g. EP 4 321 232 A1 ). Although the fluid control through holes 40 are illustrated in the drawings of the present invention in a curved shape (e.g. arc-shaped), the fluid control through holes 40 are not limited to the shapes illustrated in the drawings of the present invention and may have other shapes or shape features, such as rounded corner and the like.

[0064] The fluid control through holes 40 may include a plurality of cake formation through holes 42, 44, one or more cake washing and / or cake drying through holes 46, one or more cake blow and / or bubbling through holes 48.

[0065] The fluid control through holes 40 may be separated from each other by respective partition wall portions 34 or sealing wall portions 36. The partition wall portions 34 of embodiments of the present invention may be formed with such a size and shape so as to not be able to completely seal adjacent ones of the plurality of sealing disk through holes 24 from each other. For example, adjacent fluid control through holes separated by a partition wall portion may be subjected to the same pressure level (e.g. both to vacuum or both to overpressure). On the other hand, the 93609 14 sealing wall portions 36 of embodiments of the present invention may be formed with such a size and shape so as to be able to completely seal adjacent ones of the plurality of sealing disk through holes 24 from each other. In other words, a partition wall portion of the control disk body 32 of the present invention may have a width in circumferential direction CD, which is smaller than a width in circumferential direction CD of one of the plurality of sealing disk through holes 24. On the other hand, a sealing wall portion may have a width in circumferential direction CD, which is larger than the width in circumferential direction CD of a partition wall portion and larger than a width in circumferential direction of one of the plurality of sealing disk through holes 24. For example, adjacent fluid control through holes separated by a sealing wall portion may be subjected to different pressure levels (e.g. one to vacuum and the other one to overpressure). In this regard, the above-mentioned “width in circumferential direction CD” of a respective wall portion may refer to an angular range (or angle) covered by the respective wall portion of the control disk body 32 (e.g. when viewed along the axis through a center point CP of the control disk body 32, such as in Fig. 3). As shown for example in Fig. 3, the partition wall portions 34 or sealing wall portions 36 may trapezoidal shape (e.g. when viewed along the axis through a center point CP of the control disk body 32, such as in Fig. 3), said trapezoidal shape tapering along the radial direction toward the center point CP of the control disk body 32. The partition wall portions 34 or sealing wall portions 36 may however also have other shapes and are not limited to the shapes as illustrated herein.

[0066] In the embodiments of the present invention (see e.g. Figs. 3 and 4), one combined through hole for cake washing and cake drying may be provided as the cake washing and / or cake drying formation through hole 46. Similarly, the cake blow and / or bubbling through hole 48 may be provided as one combined through hole for cake blowing and bubble generation. The present invention is however not limited thereto. For example, the cake washing through hole and the cake drying through hole may be separate (i.e. individual) through holes and may be separated from each other through a partition wall portion or a sealing wall portion positioned therebetween. Similarly, the cake blow through hole and the bubbling through hole may be separate (i.e. individual) through holes and may be separated from each other through a partition wall portion or a sealing wall portion positioned therebetween.

[0067] In embodiments of the present invention (see e.g. Figs. 3 and 4), the cake formation through holes 42, 44 are - on one end in the circumferential direction CD - 93609 15 separated from the cake washing and / or cake drying through hole 46 through a partition wall portion or a sealing wall portion. In the stationary control disk unit 30 of Fig. 3, a second partition wall portion 34b is formed in the control disk body 32 between the cake formation through holes 42, 44 and the cake washing and / or cake drying through hole 46. The cake washing and / or cake drying through hole 46 is separated from the cake blow and / or bubbling through hole 48 through a first sealing wall portion 36a. The cake formation through holes 42, 44 are - on the other end in the circumferential direction CD - separated from the cake blow and / or bubbling through hole 48 through a second sealing wall portion 36b.

[0068] According to the present invention, the cake formation through holes comprise at least one initial cake formation through hole and at least one main cake formation through hole. The at least one initial cake formation through hole and at least one main cake formation through hole are separated from each other by a partition wall portion formed in the control disk body 32.

[0069] This may enable the filtration device 1 according to embodiments of the present invention to differentiate the filtrate into multiple different stages depending on the content of (non-filtered) solid components in the filtrate. That is, the provision of at least one initial cake formation through hole and at least one main cake formation through hole in the filtration device 1 according to embodiments of the present invention may allow the formation of an initial cake (also called “pre cake”, “precoat cake” or “primary cake”) on the outer surface 13 of the filter drum 10 in the cake formation zone covered by the at least one initial cake formation through hole and the separation of an initial filtrate with relatively higher content of solid components from the slurry via said at least one initial cake formation through hole, while also allowing the formation of a main cake (also called “mother cake” or “secondary cake”) on the outer surface 13 of the filter drum 10 in the cake formation zone covered by the at least one main cake formation through hole and the separation of a main filtrate with relatively lower content of solid components from the slurry via said at least one main cake formation through hole.

[0070] Referring to Fig. 3 illustrating an embodiment of the stationary control disk unit 30, the cake formation through holes may comprise an initial cake formation through hole 42 and a main cake formation through hole 44. A first partition wall portion 34a is formed in the control disk body 32 between the initial cake formation through hole 42 and the main cake formation through hole 44. As for example illustrated in Fig. 3, the 93609 16 main cake formation through hole 44 and the initial cake formation through hole 42 are formed immediately adjacent to each other in the control disk body 32, only separated (e.g. in the circumferential direction CD) by the first partition wall portion 34a formed in the control disk body 32.

[0071] The main cake formation through hole 44 and the initial cake formation through hole 42 are configured and arranged in the control disk body 32 such that the main cake formation through hole 44 and the initial cake formation through hole 42 are connected to the filtration cells 12, which are at least partially submerged in the slurry, via the plurality of sealing disk through holes 24 so as to receive and discharge filtrate from said at least partially submerged filtration cells 12. Due to the first partition wall portion 34a, the filtrates entering the main cake formation through hole 44 and the initial cake formation through hole 42 may be fluidly separated from each other and may thus be subject to different downstream processes and handling.

[0072] The initial cake formation through hole 42 may be formed in the control disk body 32 in advance of the main cake formation through hole 44, based on the rotation direction RD of the filter drum 10. As for example illustrated in Fig. 3, on the one hand, the main cake formation through hole 44 extends in a curved shape from the first partition wall portion 34a in the same direction as the rotation direction RD of the filter drum 10. On the other hand, the initial cake formation through hole 42 extends in a curved shape from the first partition wall portion 34a in the direction opposite to the rotation direction RD of the filter drum 10. The initial cake formation through hole 42 may have a first width W1 in circumferential direction CD, and the main cake formation through hole 44 may have a second width W2 in circumferential direction CD. The first width W1 and the second width W2 may be identical to each other or may be different to each other. In other words, the initial cake formation through hole 42 and the main cake formation through hole 44 may be symmetrical based on the first partition wall portion 34a or may be asymmetric based on the first partition wall portion 34a. In case that the first and second widths W1 and W2 are different or asymmetric, the first width W1 may be a proportion (or fraction) of the second width W2, e.g. may be in the range of 0.8 to 0.1 , in particular 0.5 to 0.2, of the first width W1 . The first and second widths W1 and W2 of the initial cake formation through hole 42 and the main cake formation through hole 44 may correspond to an angular range (or angle) covered by the respective through hole (e.g. when viewed along the axis through a center point CP of the control disk body 32, such as in Fig. 3). 93609 17

[0073] The first partition wall portion 34a extends substantially radially along a line connecting the center point CP of the control disk body 32 and a predetermined circumferential point P of the control disk body 32 (as e.g. shown in Fig. 3). The predetermined circumferential point P of the control disk body 32 may be a lowermost point of the control disk body 32. Said lowermost point of the control disk body 32 may correspond to the lowermost submergence point LP of the filter drum 10.

[0074] In the direction opposite to the rotation direction RD of the filter drum 10, the initial cake formation through hole 42 may be separated from the cake blow and / or bubbling through hole 48 by the second sealing wall portion 36b. The cake blow and / or bubbling through hole 48 and configured to be connected a source of pressurized fluid with one or more filtration cells, which are to be at least partially submerged among the plurality of filtration cells, via the plurality of sealing disk through holes. In the rotation direction RD of the filter drum 10, the main cake formation through hole 44 may be separated from the cake washing and / or cake drying through hole 46 by the second partition wall portion 34b.

[0075] With further reference to Fig. 3, the control disk body 32 may be divided into a plurality of sectors. The sectors may be adjacent to each other in the circumferential direction CD around the control disk body 32 and may be centered on the center point CP of the control disk body 32. Each sector may correspond to a process step performed during a (e.g. continuous) filtration process of the filtration device 1 . The plurality of sectors may include a cake formation sector, a cake washing and / or cake drying sector 56, a first sealing sector 57a, a cake blow sector 58a, a bubbling sector 58b and a second sealing sector 57b.

[0076] The present invention is however not limited to the order and number of sectors illustrated in Fig. 3, and there may be further or other sectors depending on the actual application and usage scenario for the filtration device. For example, the cake washing and / or cake drying sector 56 may be sub-divided (e.g. either by a partition wall portion or a sealing wall portion) into individual sub-sectors for the cake washing process and the cake drying process. Further, there may even be multiple cake washing sub-sectors when using multiple different cake washing fluids. Similarly, there may also be additional other sectors, such as e.g. additional sealing sectors.

[0077] In a filtration process of the filtration device, a process cycle, through which a respective filtration cell 12 among the plurality of filtration cells proceeds upon rotation 93609 18 of the filter drum 10 in the rotation direction RD, may for example be continuously performed in the following order: starting with the formation of a cake on the outer surface 13 of the filter drum (while forming filtrate by the liquid components) in the cake formation sector, followed by washing and drying the cake in the cake washing and / or cake drying sector 56, creating a pressure-safe seal via the first sealing sector 57a, blowing off the cake in the cake blow sector 58a, creating bubbles when submerging again in the bubbling sector 58b, and creating another pressure-safe seal via the second sealing sector 57b, then starting again with the formation of a cake in the cake formation sector.

[0078] In embodiments of the present invention, the cake formation sector comprises an initial cake formation zone 52 for forming an initial cake on the outer surface 13 of the filter drum 10, and a main cake formation zone 54 for forming a main cake on the initial cake. In the initial cake formation zone 52, the initial cake formation through hole 42 is located. In the main cake formation zone 54, the main cake formation through hole 44 is located.

[0079] Further, the cake formation sector comprises the predetermined circumferential point P of the control disk body 32. Specifically, the cake formation sector may be separated into the initial cake formation zone 52 and the main cake formation zone 54 based on the predetermined circumferential point P. For example, the initial cake formation zone 52 may form a first angular range a1 before the predetermined circumferential point P, based on a rotation direction of the filter drum. Further, the main cake formation zone 52 may form a second angular range a2 after the predetermined circumferential point P, based on the rotation direction RD of the filter drum 10. The initial cake formation through hole 42 may be formed in the control disk body 32 in the first angular range a1 , and the main cake formation through hole 44 may be formed in the control disk body 32 in the second angular range a2. As an example, the first angular range a1 and the second angular range a2 may each include a range of 0 degree to 90 degree, respectively. The first angular range a1 and the second angular range a2 may be identical to each other or may be different to each other. In other words, the initial cake formation zone 52 and the main cake formation zone 52 may be symmetrical based on the predetermined circumferential point P or may be asymmetric based on the predetermined circumferential point P. In case that the first and second angular ranges a1 and a2 are different or asymmetric, the first angular range a1 may be a proportion (or fraction) of the second angular range a2, e.g. may be in the range of 0.8 93609 19 to 0.1 , in particular 0.5 to 0.2, of the first angular range a1. Referring to the embodiment of Fig. 3, the first angular range a1 may for example be about 80 degrees, and the second angular range a2 may for example be about 40 degrees. The present invention is however not particularly limited in this regard and various values for the first angular range a1 and the second angular range a2 may be applied depending on the actual application and usage scenario for the filtration device.

[0080] The fluid connection unit 60 in an embodiment of the invention comprises a plurality of fluid lines connected to the plurality of fluid control through holes 40 of the control disk unit 30. Referring to Figs. 1 and 3, the plurality of fluid lines may comprise a main filtrate line 64, which is connected to the main cake formation through hole 44, and an initial filtrate line 62, which is separate from the main filtrate line 64 and connected to the initial cake formation through hole 42. The plurality of fluid lines of the fluid connection unit 60 may also include other fluid lines (not shown), such as e.g. a washing fluid supply line for supplying washing fluid, a washing filtrate discharge line for discharging washing filtrate (i.e. used washing filtrate), a pressurized fluid supply line for supplying pressurized fluid for cake blowing and / or bubbling and the like. The plurality of fluid lines (e.g. the initial filtrate line 62 and the main filtrate line 64) may be configured to be connected via internal piping / channels in the fluid connection unit 60 to the associated fluid control through holes 40 of the control disk unit 30.

[0081] The filtrate directed into the main filtrate line 64 is referred to herein as a “main filtrate”, and the filtrate directed into the initial filtrate line 62 is referred to herein as an “initial filtrate”. The initial filtrate may have a higher content of solid components than the main filtrate. Specifically, the formation of the initial cake in the initial cake formation zone 52 may act as a precoat for the formation of the main cake in the main cake formation zone 54, resulting in a lower content of solid components in the main filtrate compared to the initial filtrate.

[0082] The main cake formation through hole 44 and the initial cake formation through hole 42 may direct filtrate separately into the main filtrate line 64 and the initial filtrate line 62, respectively. In other words, the initial filtrate line 62 may receive initial filtrate from the initial cake formation through hole 42, and the main filtrate line 64 may receive main filtrate from the main cake formation through hole 44. Hence, the initial filtrate and the main filtrate may be separately conveyed by different fluid paths in the 93609 20 fluid connection unit 60 and the control disk unit 30, which are in connected to each other.

[0083] The main filtrate line 64 and the initial filtrate line 62 may be connected to subsequent fluid lines and / or processing stages of a filtration system, such as exemplarily described hereinbelow.

[0084] Referring now to Fig. 4, another embodiment of a stationary control disk unit 30’ is illustrated, in which a plurality of main cake formation through holes is provided, the individual main cake formation through holes being separated from each other by corresponding partition wall portions. Said stationary control disk unit 30’ accordingly differs from the stationary control disk unit 30 of Fig. 3 in that a first main cake formation through hole 44a and a second main cake formation through hole 44b are provided, and the main the main cake formation zone is accordingly sub-divided into a first main cake formation zone 54a and a second main cake formation zone 54b. Such a configuration may be useful for applications, in which multiple filtrates of different (e.g. gradually lowered) content of solid components may be separated from the slurry. Accordingly, a first main filtrate may be provided via the first main cake formation through hole 44a, and a second main filtrate second main cake formation through hole 44b. The content of solid components in the first main filtrate may be higher than the content of solid components in the second main filtrate.

[0085] With reference to Fig. 5, a filtration system according to an embodiment of the present invention is provided. The filtration system of the present invention is not limited to the configuration of Fig. 5 and may include additional components or use less components than those illustrated in Fig. 5, depending on the actual application and usage scenario.

[0086] The filtration system 100 according to an embodiment of the present invention includes a filtration device (such as filtration device 1 ) according to embodiments of the present invention. The filtration device 1 is illustrated exemplarily in Fig. 5 only through the stationary control disk unit 30 so as to illustrate the connection relationship between system components and the fluid control through holes 40 of the stationary control disk unit 30. In this regard, the illustration of the stationary control disk unit 30 in Fig. 5 is also representative of the filter drum 10. 93609 21

[0087] The filtration system 100 further comprises a main filtrate accommodating and / or processing device 110. The main filtrate accommodating and / or processing device 110 may be connected to the main filtrate line 64 and may be configured to receive the main filtrate from the main filtrate line 64. As illustrated in Fig. 5, the main filtrate accommodating and / or processing device 110 according to an embodiment of the present invention comprises a main filtrate transport line 112, a main filtrate storage device 114 and one or more subsequent main filtrate processing devices 116. The main filtrate storage device 114 is connected to the main filtrate line 64 and may store main filtrate received via the main filtrate line 64. The main filtrate storage device 114 may be a tank or reservoir or the like, and may be external to the filtration device 1 . Although not shown, the main filtrate accommodating and / or processing device 110 may also include a suction device between the main filtrate storage device 114 and the main filtrate line 64 so as to generate underpressure (e.g. vacuum) in the main filtrate line 64 in order to draw in main filtrate via vacuum from the slurry. The main filtrate transport line 112 is connected to the main filtrate storage device 114 and may transfer filtrate stored main filtrate storage device 114 out from the main filtrate storage device 114 to one or more subsequent main filtrate processing devices 116. The one or more subsequent main filtrate processing devices 116 may include various processing and storage devices for further processing the main filtrate and may depend on the actual application and usage scenario of the filtration system 100. The present invention is however not limited to the configuration illustrated in Fig. 5. In other embodiments, the main filtrate transport line 112 may be (e.g. directly) connected to or formed integrally with the main filtrate line 64 and be configured to directly transport main filtrate to the one or more subsequent main filtrate processing devices 116 (i.e. without intermediate storage in a main filtrate storage device 114).

[0088] The filtration system 100 further comprises an initial filtrate accommodating and / or recirculating device 120. The initial filtrate accommodating and / or recirculating device 120 may be connected to the initial filtrate line 62 and may be configured to receive initial filtrate from the initial filtrate line 62. As illustrated in Fig. 5, the initial filtrate accommodating and / or recirculating device 120 according to an embodiment of the present invention comprises a(n) (initial) filtrate recirculation line 122, an initial filtrate storage device 124 and a(n) (initial) recirculation pump 126. The initial filtrate storage device 124 is connected to the initial filtrate line 62 and may store initial filtrate received via the initial filtrate line 62. The initial filtrate storage device 124 may be a tank 93609 22 or reservoir or the like, and may be external to the filtration device 1 . Although not shown, the initial filtrate accommodating and / or recirculating device 120 may also include a suction device between the initial filtrate storage device 124 and the initial filtrate line 62 so as to generate underpressure (e.g. vacuum) in the initial filtrate line 62 in order to draw in initial filtrate via vacuum from the slurry. The initial filtrate accommodating and / or recirculating device 120 and the main filtrate accommodating and / or processing device 110 may utilize the same suction device together or utilize individual suction devices. The filtrate recirculation line 122 connects the initial filtrate storage device 124 and the filtration device 1 so as to recirculate the initial filtrate back into the slurry accommodating unit of filtration device 1 . To this end, an end of the filtrate recirculation line 122 is connected to the initial filtrate storage device 124 and the other end of the filtrate recirculation line 122 is connected to the filtration device 1 . In the filtration device 1 , the other end of the filtrate recirculation line 122 may open into the slurry accommodating unit of the filtration device 1 . The recirculation pump 126 is arranged in the filtrate recirculation line 122 and may be operated so as to transfer (i.e. pump) the initial filtrate through the filtrate recirculation line 122 back to the filtration device 1. The present invention is however not limited to the configuration illustrated in Fig. 5. For example, the recirculation pump 126 may be optional and may in some embodiments thus be omitted. In other embodiments, an end of the filtrate recirculation line 122 may branch off from the initial filtrate line 62 upstream of the initial filtrate storage device 124 and the other end of the filtrate recirculation line 122 may be connected to the filtration device 1. In other words, the filtrate recirculation line may recirculate only a portion of the initial filtrate from the initial filtrate line 62, while the remainder of the initial filtrate may continue to flow into the initial filtrate storage device 124 for storage therein. Further, in another embodiment, the filtrate recirculation line 122 and the initial filtrate line 62 may be directly connected to each other or formed integrally with each other (i.e. without intermediate storage in an initial filtrate storage device 124).

[0089] Referring now to Fig. 6, another embodiment of a filtration system 100 is illustrated, having a different configuration of the initial filtrate accommodating and / or recirculating device 120 than that of Fig. 5. The filtration system 100 of Fig. 6 includes a slurry feed vessel 160 configured to store and supply slurry to the slurry accommodating unit of the filtration device 1 . The slurry feed vessel 160 may be a tank or reservoir or the like, and may be external to the filtration device 1. The initial filtrate accommodating 93609 23 and / or recirculating device 120 of Fig. 6 includes an initial filtrate transport line 128, which is directly connected to or formed integrally with initial filtrate line 62 (i.e. without intermediate storage in an initial filtrate storage device 124). The initial filtrate transport line 128 may further be connected to the slurry feed vessel 160. Accordingly, the initial filtrate accommodating and / or recirculating device 120 of Fig. 6 may omit the filtrate recirculation line 122 and the recirculation pump 126, which may be provided for (e.g.) direct recirculation of the initial filtrate into the slurry accommodating unit of the filtration device 1. In another embodiment, the filtrate recirculation line 122 and the recirculation pump 126 may additionally be provided and may branch off from the initial filtrate transport line 128.

[0090] In further embodiments, the initial filtrate may not (or only at least partially) be return to the slurry (i.e. may not only at least partially be returned the initial filtrate to the slurry accommodating unit of the filtration device 1 and / or the slurry feed vessel 160), and the initial filtrate transport line 128 may alternatively or additionally be connected to subsequent initial filtrate processing devices for further processing the initial filtrate.

[0091] Various other embodiments (e.g. other arrangements and layouts, combinations of the above-described arrangements and so on) for the filtration system with the main filtrate accommodating and / or processing device and the initial filtrate accommodating and / or recirculating device may be possible, and the filtration system of the present invention is not limited to the embodiments illustrated herein, e.g. in Figs. 5 and 6.

[0092] In the filtration system 100 according to the present invention, it is possible to separate the initial filtrate, which has a higher content of solid components than the main filtrate, from the main filtrate and to recirculate the initial filtrate. This way, the utilization ratio of the liquid and solid components in the slurry can be improved, material loss can be minimized and product quality can be improved and more easily guaranteed by using the main filtrate in subsequent filtrate processing stages.

[0093] The filtration system 100 may further comprise various other components, such as a cake washing fluid device 130, a washing filtrate device 140 and a pressurized fluid device 150.

[0094] The cake washing fluid device 130 may include a cake washing fluid supply unit 132 and a cake washing nozzle unit 134. The cake washing nozzle unit 134 may be 93609 24 provided inside the filtration device 1 and may also form part of the filtration device 1 . The cake washing fluid supply unit 132 may supply cake washing fluid to the cake washing nozzle unit 134, which may be configured to spray the washing fluid onto the cake formed on the outer surface of the filter drum. Although a single cake washing fluid device 130 may be illustrated in Fig. 5, the present invention is not limited thereto, and a plurality of cake washing fluid devices 130 may be provided, when using multiple different cake washing fluids.

[0095] The washing filtrate device 140 may comprise a washing filtrate discharge line 142 and a washing filtrate discharge unit 144. The washing filtrate discharge line 142 may be connected to the cake washing and / or cake drying formation through hole 46 of the control disk unit 30 so as to discharge the washing filtrate, generated when washing the cake using the cake washing fluid supplied by the cake washing fluid device 130. The washing filtrate discharge unit 144 may receive the washing filtrate via the washing filtrate discharge line 142 and may store or otherwise process the washing filtrate. The washing filtrate discharge unit 144 may apply underpressure (e.g. vacuum) to the washing filtrate discharge line 142 so as to suck in washing filtrate and / or moisture from the cake. The washing filtrate device 140 may also serve to dry and / or dewater the cake. Although a single washing filtrate device 140 may be illustrated in Fig. 5, the present invention is not limited thereto, and a plurality of washing filtrate devices 140 may be provided, e.g. when using multiple different cake washing fluids and / or when high moisture removal performance is desired.

[0096] The pressurized fluid device 150 may comprise a pressurized fluid supply line 152 and source of pressurized fluid 154 (also referred to as “pressurized fluid source 154”). The pressurized fluid source 154 may be a source of pressurized fluid, for example pressurized gas (e.g. pressurized air), and may provide the pressurized fluid to the pressurized fluid supply line 152. The pressurized fluid supply line 152 may be connected to the cake blow and / or bubbling through hole 48 so as to provide pressurized fluid for effectuating cake blow-off (supporting the removal of the cake from the outer surface of the filter drum) and for effectuating bubble generation (bubbling) in the slurry. Although a single pressurized fluid source 154 and a single pressurized fluid supply line 152 may be illustrated in Fig. 5, the present invention is not limited thereto, and multiple pressurized fluid sources for providing different pressure levels may be provided and / or multiple pressurized fluid supply lines for separately supplying pressurized fluid for cake blow and bubbling may be provided (e.g. in case that the cake 93609 25 blow through hole and the bubbling through hole may be separate individual through holes).

[0097] With reference to Fig. 7, a method 200 of operating a filtration device according to an embodiment of the present invention is provided. The filtration device may be a filtration device (e.g. filtration device 1 ) according to embodiments of the present invention. Further, the method of Fig. 7 may also utilize / operate a filtration system comprising a filtration device according to embodiments of the present invention. Furthermore, the below described method steps may be performed subsequent to each other or parallel to each other.

[0098] The method 200 includes the steps of: rotating (S210) the filter drum 10 of the filtration device 1 at least partially submerged in the slurry, forming (S220) the initial cake on the outer surface 13 of the filter drum 10 and producing initial filtrate from the liquid components by at least partially separating solid components and liquid components of the slurry in the initial cake formation zone 52 of the cake formation sector, forming (S230) the main cake on the initial cake and producing a main filtrate from the liquid components by at least partially separating solid components and liquid components of the slurry in the main cake formation zone 54 of the cake formation sector, and transferring (S240) the main filtrate and the initial filtrate out of the filtration device 1 separately from each other via the main filtrate line 64 and the initial filtrate line 62.

[0099] The step S220 of forming of the initial cake on the outer surface 13 of the filter drum 10 may form the initial cake on a filter cloth covering the outer surface 13. The thus formed initial cake ma act as a precoat in the step S230 of forming the main cake on the initial cake. Accordingly, the initial filtrate may have a higher content of solid components than the main filtrate.

[0100] In the step S230 of forming the main cake on the initial cake, a final cake may be formed from the initial cake and the main cake. The method 200 may further include the step of removing the final cake from the outer surface 13 of the filter drum 10 before repeating the step S220 of forming an initial cake during continuous rotation of the filter drum 10.

[0101] For further processing the initial filtrate and the main filtrate, the method 200 may further include the following steps. For example, the method 200 may further 93609 26 include the step of recirculating all or at least part of the initial filtrate back to the filtration device 1 and into the slurry. The method 200 may further include the step of storing all or at least part of the initial filtrate in the initial filtrate storage device 124.

[0102] The method 200 may further include the step of storing the main filtrate in the main filtrate storage device 114. Alternatively or additionally to the storing of the main filtrate, the method 200 may further include the step of transferring the main filtrate to one or more subsequent main filtrate processing devices 116.

[0103] According to the present invention as described-above, an initial cake and initial filtrate with relatively high content of solid components may be initially formed in a dedicated initial cake formation zone, and a main cake may then be formed on the initial cake and a main filtrate may be produced by utilizing the initial cake as a precoat for the formation of the main cake in a dedicated main cake formation zone, wherein the main filtrate may have a lower content of solid components. Filtration performance and product quality may thus be improved by utilizing the initial cake as the precoat, and the main filtrate with lower content of solid components may be used in subsequent filtrate processing stages.

[0104] Further, by separately providing the initial filtrate with higher content of solid component and the main filtrate with lower content of solid components, filtration performance and product quality can be improved and more easily guaranteed. Further, the initial filtrate may be recirculated and reintroduced into the filtration process, thereby increasing the utilization of the liquid and solid components in the slurry and minimizing material loss and waste production. Accordingly, the present invention may provide for higher product quality while minimizing costs and providing or maintaining high productivity.

[0105] Further, since the present invention may allow replacement of some components of the filtration device with corresponding components in accordance with the present invention, without necessarily requiring substantial changes to the mode of operation I working principle of the filtration device, even already existing filtration devices may be retrofitted so as to implement the present invention and to realize the improvements achieved by the present invention.

[0106] The present invention has been described above in detail with reference to detailed embodiments thereof. It will be appreciated by those skilled in the art that 93609 27 changes may be made in these embodiments without departing from the principles of the present invention, the scope of which is defined in the appended claims.

[0107] Accordingly, the detailed description of the present invention is not intended to limit the present invention to the disclosed embodiments.

Claims

93609 28Claims1 . A filtration device (1 ), comprising a slurry accommodating unit configured to accommodate a slurry comprising solid components and liquid components therein and to define a slurry level (SL); a filter drum (10), said filter drum (10) being configured to rotate at least partially submerged in the slurry and comprising a plurality of individual filtration cells (12), the filtration cells (12) being configured to at least partially separate the solid and liquid components of the slurry by allowing the liquid components to enter the filtration cells (12) in the filter drum (10) as a filtrate and by retaining solid components of a predetermined size or greater on an outer surface (13) of the filter drum (10) so as to form a cake, wherein, upon rotation of the filter drum (10), one or more filtration cells (12) among the plurality of filtration cells (12) are configured to become at least partially submerged in the slurry when positioned at least partially below the slurry level (SL); a sealing disk (20), which is connected with the filter drum (10) so as to rotate together with the filter drum (10) and which comprises a plurality of sealing disk through holes (24), each sealing disk through hole (24) being in connection with a respective filtration cell (12); a stationary control disk unit (30, 30’), which is arranged stationary relative to the filter drum (10) and the sealing disk (20) and which comprises a control disk body (32) with a plurality of fluid control through holes (40), the fluid control through holes (40) comprising at least one initial cake formation through hole (42) and at least one main cake formation through hole (44), the at least one main cake formation through hole (44) and the at least one initial cake formation through hole (42) being separated from each other by at least one partition wall portion (34a), which is formed in the control disk body (32) and which is optionally formed with such a size and shape so as to not be able to completely seal adjacent ones of the plurality of sealing disk through holes (24) from each other; and a fluid connection unit (60), which comprises a plurality of fluid lines connected with the plurality of fluid control through holes (40) of the control disk unit (30, 30’), wherein the plurality of fluid lines comprises a main filtrate line (64) connected to the at93609 29 least one main cake formation through hole (44) and an initial filtrate line (62) separate from the main filtrate line (64) and connected to the at least one initial cake formation through hole (42), wherein the at least one main cake formation through hole (44) and the at least one initial cake formation through hole (42) are configured and arranged in the control disk body (32) to be connected to the one or more filtration cells (12), which are to be at least partially submerged among the plurality of filtration cells (12), via the plurality of sealing disk through holes (24) so as to receive and discharge filtrate from said one or more filtration cells (12) and to direct filtrate separately into the main filtrate line (64) and the initial filtrate line (62).

2. Filtration device (1 ) according to claim 1 , wherein the at least one initial cake formation through hole (42) is formed in the control disk body (32) in advance of the at least one main cake formation through hole (44), based on a rotation direction (RD) of the filter drum (10).

3. Filtration device (1 ) according to claim 1 or 2, wherein the control disk body (32) is divided into a plurality of sectors, each sector corresponding to a process step performed during a filtration process of the filtration device (1 ), wherein the plurality of sectors comprises a cake formation sector, wherein said cake formation sector comprises an initial cake formation zone (52) for forming an initial cake on the filter drum (10) and in which the at least one initial cake formation through hole (42) is located, and a main cake formation zone (54) for forming a main cake on the initial cake and in which the at least one main cake formation through hole (44) is located.

4. Filtration device (1) according to claim 3,93609 30 wherein said cake formation sector comprises a predetermined circumferential point (P) of the control disk body (32), wherein the initial cake formation zone (52) forms, based on a rotation direction (RD) of the filter drum (10), a first angular range (a1 ) before the predetermined circumferential point (P) and wherein the main cake formation zone (54) forms, based on a rotation direction (RD) of the filter drum (10), a second angular range (a2) after the predetermined circumferential point (P), wherein the at least one initial cake formation through hole (42) is formed in the control disk body (32) in the first angular range (a1 ) and the at least one main cake formation through hole (44) is formed in the control disk body (32) in the second angular range (a2), wherein optionally each of the first angular range (a1 ) and the second angular range (a2) includes a range of 0 degree to 90 degree.

5. Filtration device (1 ) according to claim 3 or 4, wherein the predetermined circumferential point of the control disk body is a lowermost point of the control disk body, said lowermost point of the control disk body corresponding to the lowermost submergence point, being submerged in the slurry, of the filter drum.

6. Filtration device (1 ) according to any one of claims 1 to 5, wherein the at least one main cake formation through hole (44) and the at least one initial cake formation through hole (42) are formed immediately adjacent to each other in the control disk body (32), only separated by the at least one partition wall portion (34a) formed in the control disk body (32).

7. Filtration device (1) according to any one of claims 1 to 6,93609 31 wherein the at least one main cake formation through hole (44) extends in a curved shape from the at least one partition wall portion (34a) in the same direction as the rotation direction (RD) of the filter drum (10), and wherein the at least one initial cake formation through hole (42) extends in a curved shape from the at least one partition wall portion (34a) in the direction opposite to the rotation direction (RD) of the filter drum (10), wherein optionally the at least one initial cake formation through hole (42) may have the same or a smaller width (W1 ) in circumferential direction (CD) than the width (W2) in circumferential direction (CD) of the at least one main cake formation through hole (44), wherein further optionally the at least one initial cake formation through hole (42) may have a width in circumferential direction, which is 0.8 to 0.1 , in particular 0.5 to 0.2, of the width in circumferential direction of the at least one main cake formation through hole (44).

8. Filtration device (1 ) according to any one of claims 1 to 7, in combination with claim 4 or 5, wherein the at least one partition wall portion (34a) extends substantially radially along a line connecting a center point (CP) of the control disk body (32) and the predetermined circumferential point (P) of the control disk body (32).

9. Filtration device (1 ) according to any one of claims 1 to 8, wherein the at least one partition wall portion (34a) of the control disk body (32) has a width in circumferential direction (CD), which is smaller than a width in circumferential direction (CD) of one of the plurality of sealing disk through holes (24).

10. Filtration device (1 ) according to any one of claims 1 to 9, wherein the control disk body (32) further comprises at least one sealing wall portion (36b), wherein the at least one sealing wall portion (36) has a width in circumferential direction (CD), which is larger than the width in circumferential direction (CD) of the at least one partition wall93609 32 portion (34a) and larger than a width in circumferential direction (CD) of one of the plurality of sealing disk through holes (24), wherein the control disk body (32) optionally further comprises a cake blow and / or bubbling through hole (48) separated from the at least one initial cake formation through hole (42) by said at least one sealing wall portion (36b) and configured to connect a source of pressurized fluid with one or more filtration cells (12), which are to be at least partially submerged among the plurality of filtration cells (12), via the plurality of sealing disk through holes (24).11 . Filtration device (1 ) according to any one of claims 1 to 10, wherein the filtrate directed into the main filtrate line (64) is a main filtrate, wherein the filtrate directed into the initial filtrate line (62) is an initial filtrate, wherein the initial filtrate has a higher content of solid components than the main filtrate.

12. A filtration system (100), comprising a filtration device (1 ) according to any one of claims 1 to 11 , and a main filtrate accommodating and / or processing device (110), connected to the main filtrate line (64) and configured to receive filtrate from the main filtrate line (64) as a main filtrate, an initial filtrate accommodating and / or recirculating device (120), connected to the initial filtrate line (62) and configured to receive filtrate from the initial filtrate line (62) as an initial filtrate.

13. Filtration system (100) according to claim 12, wherein the main filtrate accommodating and / or processing device (110) comprises93609 33 a main filtrate transport line (112), connected to or formed integrally with the main filtrate line (64) so as to transport main filtrate to one or more subsequent main filtrate processing devices (116).

14. Filtration system (100) according to claim 12, wherein the main filtrate accommodating and / or processing device (110) comprises a main filtrate storage device (114), connected to the main filtrate line (64) and storing main filtrate received via the main filtrate line (64), and a main filtrate transport line (112), connected to the main filtrate storage device (114) and configured to transfer filtrate out from the main filtrate storage device (114) to one or more subsequent main filtrate processing devices (116).

15. Filtration system (100) according to any one of claims 12 to 14, wherein the initial filtrate accommodating and / or recirculating device (120) comprises a filtrate recirculation line (122), being connected to the filtration device (1 ) and being configured to recirculate the initial filtrate back into the slurry accommodating unit of filtration device (1 ), wherein, optionally, the filtration system (100) further comprises a recirculation pump (126) arranged in the filtrate recirculation line (122) so as to transfer the initial filtrate back to the filtration device (1 ).

16. Filtration system (100) according to claim 15, wherein the initial filtrate accommodating and / or recirculating device (120) further comprises an initial filtrate storage device (124), connected to the initial filtrate line (62) and storing initial filtrate received via the initial filtrate line (62), wherein an end of the filtrate recirculation line (122) is connected to the initial filtrate storage device (124) and the other end of the filtrate recirculation line (122) is connected to the filtration device (1 ),93609 34 and / or wherein an end of the filtrate recirculation line (122) branches off from the initial filtrate line (62) upstream of the initial filtrate storage device (124) and the other end of the filtrate recirculation line (122) is connected to the filtration device (1 ).

17. Filtration system (100) according to claim 15, wherein the initial filtrate line (62) and the filtrate recirculation line (122) are connected to each other or formed integrally with each other.

18. Filtration system (100) according to any one of claims 15 to 17, wherein the initial filtrate accommodating and / or recirculating device (120) comprises an initial filtrate transport line (128), which is on the one hand connected to or formed integrally with the initial filtrate line (62) and is on the other hand connected to a slurry feed vessel (160) of the filtration system (100) and / or to subsequent initial filtrate processing devices, said slurry feed vessel (160) being configured to store and supply slurry to the slurry accommodating unit of the filtration device (1).

19. A method of operating a filtration device, optionally a filtration device (1 ) according to one of claims 1 to 11 , the method comprising: rotating (S210) a filter drum (10) of the filtration device at least partially submerged in a slurry comprising solid components and liquid components; forming (S220) an initial cake on an outer surface (13) of the filter drum (10) and producing an initial filtrate from the liquid components by at least partially separating solid components and liquid components of the slurry in an initial cake formation zone (52) of a cake formation sector among a plurality of sectors, each sector corresponding to a process step performed during a filtration process of the filtration device; forming (S230) a main cake on the initial cake and producing a main filtrate from the liquid components by at least partially separating solid components and liquid93609 35 components of the slurry in a main cake formation zone (54) of the cake formation sector; and transferring (S240) the main filtrate and the initial filtrate out of the filtration device separately from each other via a main filtrate line (62) and an initial filtrate line (64).

20. Method according to claim 19, further comprising recirculating all or at least part of the initial filtrate back to the filtration device and into the slurry.21 . Method according to claim 19 or 20, further comprising storing all or at least part of the initial filtrate in an initial filtrate storage device (124).

22. Method according to anyone of claims 19 to 21 , further comprising storing the main filtrate in a main filtrate storage device (114), and / or transferring the main filtrate to one or more subsequent main filtrate processing devices (116).

23. Method according to anyone of claims 19 to 22, wherein the initial filtrate has a higher content of solid components than the main filtrate.

24. Method according to anyone of claims 19 to 23, wherein the initial cake and the main cake form a final cake,93609 36 wherein the method further comprises removing the final cake from the outer surface (13) of the filter drum (10) before repeating the step of forming an initial cake.

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