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NO-349438-B9 -

NO349438B9NO 349438 B9NO349438 B9NO 349438B9NO-349438-B9

Dates

Publication Date
20260202
Application Date
20240502
Priority Date
20240502

Claims (17)

  1. 1. 349438 11 Claims 1. A water filtration unit (1) comprising a cylinder-shaped filter (2), a rotary shaft (3), a filter housing (4) and a receiver tank (5), wherein 5 the rotary shaft (3) is arranged within the filter housing (4a,4b) and configured to rotate the filter (2) around a horizontal centre axis (C) of the filter; the filter (2) comprises an open end (6), an external surface (10) and an internal surface (11); 10 the filter housing (4a,4b) comprises a water inlet (7) for water to be filtered (W1) and a first water outlet (8) for filtered water (W2), the water inlet (7) being separated from the first water outlet (8) by the filter (2), such that water entering the filter housing (4a,4b) through the water inlet (7) may only pass into the filter (2) via the external surface and the filtered water 15 must exit the first water outlet (8) via the open end (6); and the receiver tank (5) is arranged at the open end (6) of the filter to receive filtered water exiting the first water outlet (8), characterized in that the water filtration unit comprises a floating system (18,19,20) configured to 20 regulate the level of the water filtration unit (1) relative to a surface level of a body of water in which the water filtration unit is partly submerged.
  2. 2. A water filtration unit according to claim 1, wherein the receiver tank comprises, or is connectable to, a second water outlet (25) such that a level 25 (L2) of filtered water in the receiver tank (5) may be kept at a lower level than the level (L1) of water to be filtered in the filter housing, during use.
  3. 3. A water filtration unit according to claim 1 or 2, comprising, or being connectable to, a pump (9) configured to transfer filtered water out of the 30 receiver tank via the second water outlet (25).
  4. 4. A water filtration unit according to any of the preceding claims, wherein the water inlet (7) and the filter housing (4a,4b) are configured such that the level (L1) of water to be filtered inside the filter housing will be equal to a 35 surface level (L1) of a body of water when the water filtration unit is partly submerged in the body of water during use.
  5. 5. A water filtration unit according to any of the preceding claims, comprising a water pipe (23) having an upper end and a lower end, the upper end 40 connected to the water inlet (7) such that water may only enter the water inlet via the lower end of the water pipe. 349438 12
  6. 6. A water filtration unit according to any of the preceding claims, wherein the filter housing (4a,4b) comprises sidewalls (21) on opposite sides of the filter (2) and a bottom panel (22), wherein the water inlet (7) comprises an opening arranged in the bottom panel. 5
  7. 7. A water filtration unit according to any of the preceding claims, comprising a first sensor for measuring the level (L1) of water to be filtered inside the filter housing (4a,4b).
  8. 10 8. A water filtration unit according to claim 7, wherein the first sensor is connected to a control system of the water filtration unit, the control system configured to regulate the level of the water filtration unit relative to a surface level (L1) of a body of water when the filtration unit is partly submerged in the body of water during use, such that the level (L1) of water 15 to be filtered inside the filter housing may be regulated.
  9. 9. A water filtration unit according to any of the preceding claims, comprising a second sensor (14) for measuring the level (L2) of filtered water in the receiver tank (5) or inside the filter. 20
  10. 10. A water filtration unit according to claim 9, wherein the second sensor (14) is connected to a control system of the filtration unit, the control system configured to regulate a flow of water out of the receiver tank (5) such that the level (L2) of filtered water inside the filter or in the receiver tank is 25 maintained between a maximum level and a minimum level.
  11. 11. A water filtration unit according to any of the preceding claims, comprising a plurality of nozzles (12) and a chute (13), the nozzles (12) arranged within the filter (2) and configured to direct pressurized water onto the internal 30 surface (11), such that particles collected on the external surface (10) is removed, and the chute is arranged at the external surface (10) to guide water from the nozzles and the particles away from the filter.
  12. 12. A water filtration unit according to any of the preceding claims, comprising 35 an electric motor (15) configured to rotate the rotary shaft (3), optionally via a gear assembly (16,17).
  13. 13. A water filtration system comprising a water filtration unit according to any of the preceding claims, wherein the water filtration unit is configured to be 40 partly submerged in a body of water such that the level of water to be filtered being inside the water filtration unit is equal to the surface level of the body of water. 349438 13
  14. 14. A water filtration system according to claim 13, wherein the floating system comprises a floating element (18), a ballast tank (19) and a ballast tank pump (20). 5
  15. 15. A water filtration system according to claims 13 or 14, wherein the water filtration unit comprises a first sensor for measuring the level of water to be filtered inside the filter housing, and the sensor is in communication with the floating system, optionally via a control system, such that the level of the 10 water filtration unit relative to the surface level of the body of water, and the capacity of the filter, may be regulated.
  16. 16. A water filtration system according to any of claims 13-15, comprising a pump (9) configured to transfer filtered water out of the receiver tank via the 15 second water outlet (25).
  17. 17. A method of regulating the water filtering capacity of a water filtration unit according to any of claims 1-12 or a water filtration system according to any of claims 13-16, the method comprises the steps of: 20 - arranging the water filtering unit (1) in a body of water; - measuring the level of water to be filtered (L1) in the filter housing (4a,4b); and - increasing or decreasing the water filtering capacity of the filter (2) by 25 respectively lowering or raising the water filtration unit relative to a surface level of the body of water. 30 349438 14

Description

[0001] 349438 [0004] 1 [0006] Water filtration unit [0008] Field of the invention [0009] The present invention relates to a water filtration unit, a water filtration system 5 comprising the water filtration unit, and a method for filtration of water. [0011] Background [0013] In many applications there is a need for providing a large volumetric flow of 10 filtered water, e.g. in fish farms based on the flow-through method. Such fish farms may be land based or comprise a floating structure having a closed-off fish farming pen. [0015] The water is often sourced from a sea depth of 20-30 meters to reduce or eliminate 15 the presence of sea lice and to obtain a desired water temperature. [0017] In the prior art water filtration systems, water is commonly obtained by using a suction pump connected to a water pipe to both transport the water up from the desired depth and through a filter. The solution is not energy efficient and requires a 20 powerful high-capacity pump to overcome a pressure differential needed to filter the water. [0019] WO 2019/198063 A1 discloses a fish farm based on the flow-through method. The water for the land based fish farm may be retrieved from various depths, from 25 below 120 meters to 25 meters, depending on the time of year to obtain water at a desired temperature. To transfer the water from the sea to a pool of the fish farm, a pipe is arranged having a water intake at the required sea depth and an outlet connected to a suction pump. The suction pump must be sufficiently powerful to overcome the pressure differential between the water intake and an outlet side of a 30 pressure filter arranged within the pool of the fish farm. [0021] Patent documents US10792595B2, US5558042A and CN220245620U disclose various water filtration units based on the use of drum filters. [0023] 35 The goal of the present invention is to provide an improved water filtration system, in which at least some of the disadvantages of the prior art systems are avoided or alleviated. In particular, the present invention provides a water filtration system capable of providing large volumes of filtered water in a highly energy efficient manner. [0024] 40 [0025] Summary of the invention [0026] 349438 [0029] 2 [0031] The present invention is defined by the appended claims and in the following: [0033] In a first aspect, the present invention provides a water filtration unit comprising a cylinder-shaped filter, a rotary shaft, a filter housing and a receiver tank, wherein 5 the rotary shaft is arranged within the filter housing and configured to rotate the filter around a horizontal centre axis of the filter; [0034] the filter comprises an open end, an external surface and an internal surface; [0035] the filter housing comprises a water inlet for water to be filtered and a 10 first water outlet for filtered water, the water inlet being separated from the first water outlet by the filter, such that water entering the filter housing through the water inlet may only pass into the filter via the external surface (i.e. pass into a cylindrical space defined by the internal surface of the filter) and the filtered water must exit the first water outlet via the open end; and 15 the receiver tank is arranged at the open end of the filter to receive filtered water exiting the first water outlet, wherein [0037] the water filtration unit comprises a floating system configured to regulate the level of the water filtration unit relative to a surface level of a body of 20 water in which the water filtration unit is partly submerged. [0039] In other words, the water inlet may be separated from the first water outlet by the filter such that water entering the filter housing through the water inlet may only exit via the open end by passing into the filter via the external surface. [0040] 25 [0041] The water filtration unit may be configured to be partly submerged in a body of water during use, the body of water providing the water to be filtered. [0043] The water filtration unit may comprise or be directly or indirectly connected to a 30 height regulating system configured to maintain the filtration unit partly submerged in a body of water at a desired level during use. The height regulating system may be a floating system or support system. The support system may e.g. be an elevator system configured to raise and lower the filtration system relative to a platform fixed to the bottom of the body of water. [0044] 35 [0045] The filter may comprise a second end arranged opposite the open end, the second end may be closed off by the filter housing or may be open to provide filtered water to a second receiver tank. [0047] 40 The filter housing may comprise a frame in which the rotary shaft and filter is arranged, and a cradle housing into which the frame may be lowered. [0048] 349438 [0051] 3 [0053] In an embodiment of the water filtration unit, the rec