Disc panel unit, disc filter disc and disc filter apparatus

Abstract

The present invention describes a disc filter disc (1) intended for a disc filter apparatus, said disc filter disc (1) comprising - multiple post units (2) which are attachable and detachable to a center drum (3) of the disc filter apparatus, wherein each post unit (2) has locking portions (211) being locking grooves, holes or slots (211) provided on opposite sides of each post unit (2); - multiple panels (4), wherein each panel (4) has fastening portions (41) which are arranged to be fastened to and unfastened from said locking portions (211) of a post unit (2), to form a disc panel unit (10); wherein the multiple post units (2) and the multiple panels (4) are part of a framework of the disc filter disc (1).

Description

[0001] DISC PANEL UNIT, DISC FILTER DISC AND DISC FILTER APPARATUS

[0002] Field of the invention

[0003] The present invention relates to a disc panel unit, to a disc filter disc comprising the disc panel units and to a disc filter apparatus comprising the same.

[0004] Technical Background

[0005] There are several existing disc filter concepts and apparatus. One example is described in EP2244802, which provides a disc filter comprising filter elements, each filter element comprising a framework carrying a filter cloth on both its side surfaces, where the framework and the filter cloth are permanently joined together forming a single use filter element, and wherein the filter element has at least one passage in each edge for liquid communication between the inside of adjacent filter elements when these adjacent filter elements are mounted edge to edge forming a filter disc.

[0006] One aim of the present invention is to provide a disc filter concept which provides advantages in terms of flexibility for a user and increased simplicity when being assembled and during maintenance events and the like. Summary of the invention

[0007] The latter stated purpose above is achieved by a disc filter disc intended for a disc filter apparatus, said disc filter disc comprising

[0008] - multiple post units which are attachable and detachable to a center drum of the disc filter apparatus, wherein each post unit has locking portions being locking grooves, holes or slots provided on opposite sides of each post unit;

[0009] - multiple panels, wherein each panel has fastening portions which are arranged to be fastened to and unfastened from said locking portions of a post unit, when being fastened to form a disc panel unit; wherein the multiple post units and the multiple panels are part of a framework of the disc filter disc.

[0010] It should be noted that the disc filter disc according to the present has post units with locking grooves, holes or slots which match fastening portions of the panels, or the other way around, that is with locking grooves, holes or slots being arranged on the panels and the matching locking portions on the post units instead. The important perspective is that the post units and panels can be fixed to and dissembled from one another.

[0011] Furthermore, the post unit according to the present invention has locking portions being locking grooves, holes or slots provided on opposite sides of each post unit. To provide these locking grooves, holes or slots on both sides of each post unit is important to ensure stability for the entire disc filter disc when the post units and panels are fastened to each other. In this regard it may also be mentioned that the disc filter discs according to the present invention provides an improved disc filter disc in which the disc filter panels are fastened in a very stable way and where the accessible filter area is increased. This is further discussed below.

[0012] To provide a high filter area while at the same time ensure a high stability is a key feature according to the present invention. This is not provided by known disc filter discs in the same improved way. For instance, in WO 2009 / 011862 A1 there is shown an alternative of a disc filter disc and system therefore, however in this case the stability is ensured by providing cross sectional enforcement ribs which in themselves limit the filter area. Moreover, the solution in WO 2009 / 011862 A1 requires a higher number of post units to ensure a reasonable stability for the disc filter system shown therein.

[0013] Furthermore, and as stated above, the disc filter discs according to the present invention comprise multiple post units which are part of a framework of the disc filter disc. This implies that the post units in fact provides the segments of the disc filter disc. This is not the case in other existing disc filter discs. As a comparison, in EP2244802, the filter elements one by one provide for the disc filter disc, and thus the framework mentioned in is EP2244802 in the filter element as such, and there is therefore no full framework provided by posts to form the entire disc filter disc such as according to the present invention.

[0014] Other advantages of the present invention will become clear when reading the below, also together with the drawings. Brief description of the drawings

[0015] In fig. 1 there is shown one embodiment of the present invention, in this case linked to how post units are attached to a center drum of a disc filter apparatus.

[0016] In fig. 2a there is shown one embodiment of the present invention, in line with the one in fig. 1 , however also with an intermediate post unit and panels being fixed.

[0017] In fig. 2b there is shown one embodiment of a post unit according to the present invention.

[0018] In fig. 3 there is shown one embodiment of the present invention, again in line with the one already presented, but in this with fixed panels and a cover unit being shown.

[0019] In fig. 4 there is shown one embodiment of the present invention where the cover unit has been locked into the disc panel unit of the disc filter disc.

[0020] In fig. 5a and 5b there are shown a panel according to one embodiment of the present invention.

[0021] In fig. 6 and 7 there are shown yet another embodiment of the present invention.

[0022] In fig. 8 there is shown a disc filter disc according to one embodiment of the present invention.

[0023] In figs. 9a and 9b there is shown one embodiment of the present invention, which embodiment is an alternative to the one shown in figs. 3 and 4.

[0024] Specific embodiments of the invention

[0025] Below some specific embodiments of the present invention are disclosed and discussed further.

[0026] According to one embodiment, dual panels are arranged at a distance from each other between two adjacent post units to form the disc panel unit. It should be noted that two panels may have been connected to one single panel unit before being attached and fixed to the post units of the disc filter disc. Nevertheless, two panel sides with a space in between should be provided by these panel sides. This space is intended for water flowing which is being filtrated. According to yet another embodiment, each post unit has one or more continuous holes for water flowing from one disc panel unit to an adjacent disc panel unit. The continuous holes ensure for liquid connection between different disc filter segments on each side of a single post unit. Moreover, examples are shown in the drawings where two continuous holes are provided in the post units. Furthermore, the continuous holes are arranged so that open frame units may be connected into the continuous holes. These may function to ensure further separation capability of particles from a water flow.

[0027] According to one embodiment, wherein each post unit has locking portions provided on opposite sides of the post unit and arranged on each end side of the post unit, more preferably several locking portions are arranged on each end side of the post unit, more preferably the locking portions are arranged angled into the material of the post unit, most preferably the locking portions are in the form of locking grooves. One example thereof is shown in fig. 2b.

[0028] Furthermore, according to yet another embodiment, each panel has fastening portions in the form of lips which are insertable into the locking grooves to fasten two panels between two adjacent post units on end sides of the two adjacent post units. One example thereof is shown in figs. 5a and 5b.

[0029] It should again be noted that according to the present invention it is also possible with an alternative where the lips instead are provided on the post units and then with panels having matching grooves to these lips.

[0030] These matching locking portions and fastening grooves have several functionalities. By fixating the panels into the post units it is ensured to keep the panels in their intended position. During use, and thus rotation of the center drum, the panels are brought up and down continuously, and the material is exposed to a potential deformation force. Also the pressurization exposes the panels to forces pushing the panels out from their original position. The locking of the panels according to the present invention ensures to keep the panels in place without fatigue, despite these forces. Moreover, this also ensures that the filter cloth of the panels are kept in a stretched condition. These benefits are key functionalities according to the present invention, and these are obtained without incorporating more material strength in the panels or reinforcements “stealing” potential filter surface area.

[0031] According to yet another embodiment, the multiple panels are arranged to be fastened in the framework of the disc filter disc to extend forces in at least an x coordinate direction and an y coordinate direction in a geometrical plane extending from one post unit cross over the panel to another post unit and extending from one disc filter disc to another adjacent disc filter disc, preferably also in an z coordinate direction in or out perpendicular from the geometrical plane. With reference to the x, y and z coordinates, reference can be made to figures 4a, 5 and 9b. Here it should also be noted that to provide locking portions on both sides of the post units is important to ensure that the disc filter disc should be able extend forces in both a minus and a plus x coordinate direction. Fact is that according to the present invention, the disc filter discs may extend both minus and plus directions in all of x, y and z coordinates. This advantage also provides for even further filter area as no enforcements are needed across the filter panels. Furthermore, in +x direction the disc filter panel is locked by the grooves in the main post units, in +y direction the disc filter panel is locked in position by the main post units, the intermediate post units, the drum holes and the cover unit (lid). In +z the disc filter panel is locked via the hooks in the drum and via the snap hooks in the cover unit (lid).

[0032] Moreover, the stability provided according to the present invention is crucial to diminish the risk of fatigue or cracks of the filter panels when exposed to pressure changes when being rotated down into and up from water.

[0033] Moreover, angled locking portions into the material of the post unit even further ensure a stable construction with extension of forces in the x and y coordinates.

[0034] Again, the disc filter disc according to WO 2009 / 011862 A1 is in need of enforcements across the filter panels as the panels are not fastened such as in accordance with the concept according to the present invention.

[0035] As should be understood from the above, the disc filter discs according to the present invention exhibit a large filter area in comparison to other disc filter discs. According to one embodiment, the disc filter disc according to the present invention has a ratio of effective filter area to total disc area of at least 65%, preferably at least 70%, more preferably at least 72%. In this regard it should also be noted that a further advantage linked to this result is the need of less material and less components in a disc filter disc according to the present invention, when compared to known solutions.

[0036] According to yet another embodiment of the present invention, each panel has a middle reinforcement portion. Such a middle reinforcement portion has several functionalities. First of all, also this may ensure to keep the panel in place in the disc filter disc when it is pressurized. Otherwise there is a risk for weakening of the construction and the material may be bent outwards. Secondly, this alternative also enables to keep the total filtration area high, which is important for the capacity. The alternative is otherwise to strengthen the panels with ribs or bars which “steal” possible filtration area of the panels. Moreover, the middle reinforcement portion also ensures to keep the filter cloth in a stretched condition. Furthermore, it may also be an aid when forcing the construction into a certain wanted position. Again to ensure a stretched filter cloth when the disc filter is used.

[0037] Another alternative according to the present invention is to provide intermediate post units. These may be provided so that the panels do not need to have middle reinforcement portion. It should be noted that the combination is also totally possible, that is with intermediate post units and still with panels having middle reinforcement portions. In line with the above, according to one embodiment, the disc filter disc also comprises intermediate post units arranged as reinforcement between two adjacent post units, preferably each intermediate post unit has continuous holes for water flowing, more preferably the intermediate post unit is attachable and detachable to the middle reinforcement portions of two opposite panels, preferably via extending stiffeners of the middle reinforcement portions and fastening grooves of the intermediate post unit provided on each end side of the intermediate post unit. Embodiments including intermediate post units are shown in figs. 2a, 3 and 4. The intermediate post units may also have other benefits. According to one embodiment, these intermediate post units may be arranged with an open II profile providing a channel for extra pellet and particle capture. This feature may be provided on both sides of the intermediate post units. Furthermore, also the regular post units may have such capabilities to capture pellets and particles.

[0038] Furthermore, one advantage of the concept according to the present invention is the module functionality, i.e. simplicity to assemble and dissemble. The fastening means may be provided in different ways according to the present invention. According to one embodiment, the multiple post units are fastened to the center drum of the disc filter apparatus with screws. One such alternative is shown in fig. 1.

[0039] According to yet another embodiment of the present invention, the disc filter disc comprises cover units which are connectable to upper ends of the post units and over two opposite panels to enclose the disc panel unit. The cover units may be provided in different forms and with different type of functionality. The common aspect is that the cover unit locks a disc filter segment tightly together so that the entire framework is fixed, and the filter cloth is stretched as supposed. The post units and panels with matching locking portions and fastening portions also enable some flexibility so that the entire framework can be fixed tightly when the cover units lock the entire structure. The cover units ensure tightening of the entire framework and panels and lock the panels in both a vertical direction and a horizontal direction along the disc filter disc.

[0040] According to one embodiment of the present invention, wherein the cover units are hinged with a joint portion in one end attachable to an upper end of one post unit and wherein each cover unit comprises locking means in the other end thereof, said locking means enabling locking of the cover unit to an upper end of an adjacent post unit, preferably locking of the cover unit to a locking portion of the upper end.

[0041] It may be mentioned that embodiments of the present invention, and linked to the above alternatives, are shown in figs. 3, 4, 6 and 7. According to yet another embodiment of the present invention, the locking means in the other end of the cover units each is arranged with a buckle unit enabling both locking and stretching of an entire disc filter disc. One such embodiment is provided in fig. 7.

[0042] According to yet another embodiment, each panel constitutes an outer part of a circular sector with a frame surrounding one or more filter surface(s), preferably wherein each panel has a middle reinforcement portion so that each panel has two filter surfaces, one on each side of the middle reinforcement portion. As mentioned above, intermediate post units may also be used, and then middle reinforcement portions of the panels are not as important. Moreover, as mentioned before, the important aspect is to ensure as high filter surface area as possible, but still provide a rigid structure possible to tighten and fix (mount) at the right position, without the risk for fatigue of the panels.

[0043] According to yet another embodiment of the present invention, the multiple panels comprise filter cloth fastened to a frame of each panel to an open area inside the frame, and wherein the filter cloth covers the entire open area(s), preferably on both open areas of a middle reinforcement portion. As mentioned above, this implies that the filter panels according to the present invention do not have any cross sectional enforcement ribs which limit the total filter area. The only portions on the filter panel not being filter cloth provided according to the present invention are the peripheral filter framework and the preferred middle reinforcement portions.

[0044] Furthermore, according to yet another embodiment, an outermost portion of the frame has fastening portions to be fixed into locking grooves, holes or slots provided on one or both sides of a cover unit. For example, these fastening portions may be lips as shown in embodiments provided in figs. 5a and 6.

[0045] According to one embodiment of the present invention, an outermost portion of the frame has an extending stiffener, preferably wherein the middle reinforcement portion has an extending stiffener. Embodiments are shown in figs. 5a and 5b. The extending stiffener provided on the outermost portion of the frame is provided to ensure stability so that the disc filter segment keeps when a filter cloth is fastened onto the panel and stretched. Moreover, the panels should hold their shape when the filter cloth is fastened onto the panel and stretched, and also when water pressure is applied.

[0046] The extending stiffener provided on the middle reinforcement portion is a possibility as an alternative to intermediate post units, or as an add-on to such.

[0047] According to yet another embodiment, an innermost portion of the frame comprises guides intended to be positioned against the center drum. Also these guides may be provided to further ensure that panels are not pushed outwards when a water pressure is applied. It should be noted that instead of guides provided on the panel, other types of units, e.g. barbs, may be used which fastens each panel to the center drum.

[0048] As hinted above, the concept of the present invention ensures to keep the panels in place so that there is no problematic axial or radial movement of the panels when the disc filter disc and system is pressurized.

[0049] According to yet another embodiment, filter cloth is fastened to the frame of each panel to open areas inside the frame so that filter cloth is provided on a both sides of the disc filter disc.

[0050] Moreover, the present invention also provides a disc filter apparatus comprising multiple disc filter discs according to the present invention, which disc filter discs are fixed around a center drum and into holes of the center drum. The disc filter apparatus according to the present invention may be used in any type of technical application. It should, however, be noted that aqua culture application, such as fish farming is of special interest. Based on this, the present invention also refers to use of a disc filter apparatus according to the present invention, in aqua culture applications, especially in use for water purification in fish farming.

[0051] As hinted above, the present invention exhibits several advantages in comparison with known disc filter systems.

[0052] Firstly, mounting or assembling and dissembling of the disc filter apparatus is simplified in comparison to known devices. This is important during maintenance and washing procedures etc. Moreover, it should be noted that no tools are needed when performing such operations. Secondly, the disc filter apparatus according to the present invention is based on modules and individual repetitive components, which implies that the system may be adjusted in a simple manner for specific user needs, such as for specific capacity needs.

[0053] Furthermore, and as mentioned, the disc filter disc according to the present invention provides both flexibility and stability. The device is possible to adjust and fix so that the disc filter cloth is stretched and stays in place when an apparatus according to the present invention is pressurized. Moreover, the concept according to the present invention also ensures that a high filter area can be obtained, without limiting the stability. The different components included and discussed above contribute in different ways to provide for these benefits.

[0054] Detailed description of the drawings

[0055] In fig. 1 there is shown one embodiment of the present invention. The disc filter disc 1 comprises multiple post units 2 which are attachable and detachable to a center drum 3 of a disc filter apparatus. As an example, a center drum may hold a number of disc filter discs, such as e.g. 12 or 14 disc filter discs. Moreover, the center drum 3 may be of plastic or metal.

[0056] Each post unit 2 has locking portions 211 , in this case locking grooves, holes or slots 211 , provided on opposite sides of each post unit 2 (see also fig. 2b). In this case, the multiple post units 2 are fastened to the center drum 3 of the disc filter apparatus with screws 6. Each post unit 2 has two continuous holes 22 for water flowing from one disc panel unit 10 to an adjacent disc panel unit 10.

[0057] In fig. 2a there is shown one embodiment of the present invention, in line with the one in fig. 1 . Here one also can see the multiple panels 4 being part of the disc filter disc, wherein each panel 4 has fastening portions 41 which are arranged to be fastened to and unfastened from said locking portions 211 of the post unit 2, when being fastened to form a disc panel unit 10.

[0058] Furthermore, in this case there is also provided intermediate post units 5 arranged as reinforcement between two adjacent post units 2. The intermediate post unit 5 has continuous holes 52 for water flowing (see fig. 3), and the intermediate post unit 5 is attachable and detachable to middle reinforcement portions 42 of two opposite panels 4. As seen in fig. 5a, the panel 4 has an extending stiffener 421 of the middle reinforcement portion 42, and. The panel 4 is adapted to fit into fastening grooves 511 of the intermediate post unit 5.

[0059] As seen in fig. 2a, the disc filter disc 1 also comprise a cover unit 7. According to this embodiment, the cover unit 7 is hinged with a joint portion 71 in one end attachable to an upper end of one post unit 2 and where the cover unit 7 also comprises locking means 72 in the other end thereof, said locking means 72 enabling locking of the cover unit 7 to an upper end of an adjacent post unit 2, preferably locking of the cover unit 7 to a locking portion 251 of the upper end (see fig. 3).

[0060] In fig. 3, the same type of embodiment is shown, however here is also shown that an outermost portion of the frame 43 of the panels 4 has fastening portions 431 to be fixed into locking grooves, holes or slots 73 provided on one or both sides of the cover unit 7. This further enables a stretch of the disc filter disc and the filter cloth and entire framework.

[0061] In fig. 4 there is shown one embodiment of the present invention where the cover unit 7 has been locked into the disc panel unit 10 of the disc filter disc 1 .

[0062] In fig. 5a and 5b there are shown a panel according to one embodiment of the present invention. In addition to what has been mentioned above, here is also shown that an outermost portion of the frame 43 has an extending stiffener 432. Moreover, an innermost portion of the frame 43 comprises guides 411 intended to be positioned against the center drum 3. As seen in fig. 5b, the filter cloth 200 is fastened to the frame 43 of each panel 4 to open areas inside the frame 43 so that filter cloth 200 is provided on a both sides 1a, 1 b of the disc filter disc 1 (see fig. 8).

[0063] In fig. 6 and 7 there are shown yet another embodiment of the present invention. In this case, there are no intermediate post units 5. The panels 4, however have extending stiffeners 421 of the middle reinforcement portions 42. The cover unit 7 has locking means 72 with a buckle unit 721 enabling both locking and stretching of an entire disc filter disc 1 . In fig. 8 there is shown a full disc filter disc 1 according to one embodiment of the present invention.

[0064] In figs. 9a and 9b there are shown an embodiment similar to the one shown in figs. 3 and 4, however in this case there is also provided mid locking means 720 which fasten to mid locking portions 2510.

Claims

Claims1 . A disc filter disc (1 ) intended for a disc filter apparatus, said disc filter disc(1 ) comprising- multiple post units (2) which are attachable and detachable to a center drum (3) of the disc filter apparatus, wherein each post unit (2) has locking portions (211 ) being locking grooves, holes or slots (211 ) provided on opposite sides of each post unit (2);- multiple panels (4), wherein each panel (4) has fastening portions (41) which are arranged to be fastened to and unfastened from said locking portions(211 ) of a post unit (2), when being fastened to form a disc panel unit (10); wherein the multiple post units (2) and the multiple panels (4) are part of a framework of the disc filter disc (1 ).

2. The disc filter disc (1 ) according to claim 1 , wherein dual panels (4) are arranged at a distance from each other between two adjacent post units (2) to form the disc panel unit (10).

3. The disc filter disc (1 ) according to claim 1 or 2, wherein each post unit (2) has one or more continuous holes (22) for water flowing from one disc panel unit (10) to an adjacent disc panel unit (10).

4. The disc filter disc (1 ) according to any of claims 1 -3, wherein each post unit (2) has locking portions (211 ) provided on opposite sides of the post unit(2) and arranged on each end side of the post unit (2), more preferably several locking portions (211 ) are arranged on each end side of the post unit (2), more preferably the locking portions (211) are arranged angled into the material of the post unit (2), most preferably the locking portions (211) are in the form of locking grooves (211 ).

5. The disc filter disc (1) according to claim 4, wherein each panel (4) has fastening portions (41 ) in the form of lips which are insertable into the lockinggrooves (211 ) to fasten two panels (4) between two adjacent post units (2) on end sides of the two adjacent post units (2).

6. The disc filter disc (1 ) according to any of claims 1 -5, wherein the multiple panels (4) are arranged to be fastened in the framework of the disc filter disc (1 ) to extend forces in at least an x coordinate direction and an y coordinate direction in a geometrical plane extending from one post unit (2) cross over the panel to another post unit (2) and extending from one disc filter disc (1 ) to another adjacent disc filter disc (1 ), preferably also in an z coordinate direction in or out perpendicular from the geometrical plane.

7. The disc filter disc (1 ) according to any of claims 1 -6, wherein the disc filter disc (1 ) has a ratio of effective filter area to total disc area of at least 65%, preferably at least 70%, more preferably at least 72%.

8. The disc filter disc (1 ) according to any of claims 1 -7, wherein each panel(4) has a middle reinforcement portion (42).

9. The disc filter disc (1 ) according to any of claims 1 -8, wherein the disc filter disc (1 ) also comprises intermediate post units (5) arranged as reinforcement between two adjacent post units (2), preferably each intermediate post unit(5) has continuous holes (52) for water flowing, more preferably the intermediate post unit (5) is attachable and detachable to the middle reinforcement portions (42) of two opposite panels (4), preferably via extending stiffeners (421 ) of the middle reinforcement portions (42) and fastening grooves (511 ) of the intermediate post unit (5) provided on each end side of the intermediate post unit (5).

10. The disc filter disc (1 ) according to any of claims 1 -9, wherein the multiple post units (2) are fastened to the center drum (3) of the disc filter apparatus with screws (6).11 . The disc filter disc (1 ) according to any of claims 1 -10, wherein the disc filter disc (1 ) comprises cover units (7) which are connectable to upper ends of the post units (2) and over two opposite panels (4) to enclose the disc panel unit (10).

12. The disc filter disc (1 ) according to claim 11 , wherein the cover units (7) are hinged with a joint portion (71 ) in one end attachable to an upper end of one post unit (2) and wherein each cover unit (7) comprises locking means (72) in the other end thereof, said locking means (72) enabling locking of the cover unit (7) to an upper end of an adjacent post unit (2), preferably locking of the cover unit (7) to a locking portion (251 ) of the upper end.

13. The disc filter disc (1) according to claim 12, wherein the locking means (72) in the other end of the cover units (7) each is arranged with a buckle unit (721 ) enabling both locking and stretching of an entire disc filter disc (1 ).

14. The disc filter disc (1 ) according to any of claims 1 -13, wherein each panel (4) constitutes an outer part of a circular sector with a frame (43) surrounding one or more filter surface(s), preferably wherein each panel (4) has a middle reinforcement portion (42) so that each panel (4) has two filter surfaces, one on each side of the middle reinforcement portion (42).

15. The disc filter disc (1 ) according to any of claims 1 -14, wherein the multiple panels (4) comprise filter cloth (200) fastened to a frame (43) of each panel (4) to an open area inside the frame (43), and wherein the filter cloth (200) covers the entire open area(s), preferably on both open areas of a middle reinforcement portion (42).

16. The disc filter disc (1) according to claim 14 or 15, wherein an outermost portion of the frame (43) has fastening portions (431 ) to be fixed into locking grooves, holes or slots (73) provided on one or both sides of a cover unit (7).

17. The disc filter disc (1 ) according to any of claims 14-16, wherein an outermost portion of the frame (43) has an extending stiffener (432),preferably wherein the middle reinforcement portion (42) has an extending stiffener (421).

18. The disc filter disc (1 ) according to any of claims 14-17, wherein an innermost portion of the frame (43) comprises guides (411 ) intended to be positioned against the center drum (3).

19. The disc filter disc (1 ) according to any of claims 14-18, wherein filter cloth(200) is fastened to the frame (43) of each panel (4) to open areas inside the frame (43) so that filter cloth (200) is provided on a both sides (1 a, 1 b) of the disc filter disc (1 ).

20. A disc filter apparatus (100) comprising multiple disc filter discs (1 ) according to any of claims 1 -19, which disc filter discs (1 ) are fixed around a center drum (3) and into holes (30) of the center drum (3).21 . Use of a disc filter apparatus (100) according to claim 20, in aqua culture applications, especially in use for water purification in fish farming.

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