A magnetic filter apparatus and a filtering system

Abstract

The present disclosure relates to a magnetic filter apparatus (1) for separating magnetic particles (10a) from liquid (10b) comprising a plurality of rods (2), a driving means (3) arranged to drive each of the plurality of rods (2) in a loop and a removal device (4) arranged to remove captured magnetic particles from each rod (2). Furthermore, the wherein the loop defines a trajectory having a lower portion (u1) and an upper portion (u2), wherein the lower portion (u1) is arranged to be immersed in liquid (10b), wherein the driving means (3) is arranged to drive the rods (2) to enable each rod (2) to, when being in the lower portion (u1), be immersed in said liquid (10b) for an initial time-period to capture said magnetic particles (10a).

Description

[0001] A magnetic filter apparatus and a filtering system.

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to a magnetic filter apparatus and a filtering system for separating magnetic particles from liquid.

[0004] BACKGROUND

[0005] Offshore drilling operations often involve the use of heavy machinery and metallic equipment, which can result in the production of magnetic particles as by-products. These particles can be released into the surrounding water, posing a risk to marine ecosystems by contaminating the habitat of various marine species. If not properly managed, these particles can accumulate and cause long-term environmental damage. Therefore, it is crucial to implement effective measures to control and mitigate the release of magnetic particles during offshore drilling activities to protect marine life and preserve ocean health.

[0006] Magnetic filters are conventionally used to remove magnetic substances from such industrial process streams. However, prior art magnetic filter apparatuses are deficient in that the filters are low capacity with uneven contaminant capture. In other words, the conventional magnetic filter apparatuses are generally not as efficient as desirable.

[0007] Accordingly, there is a need in the present art to provide a magnetic filter apparatus which more efficiently can capture magnetic particles from liquid.

[0008] SUMMARY

[0009] It is therefore an object of the present disclosure to alleviate at least some of the mentioned drawbacks to provide a magnetic filter apparatus and a filtering system. The filter apparatus and system herein are suitable for filtering liquids contaminated during an off-shore drilling operation. The apparatus may be utilized in a cleaning process in an off-shore drilling operation. Accordingly, when drilling underwater, liquid residues comprising e.g. water, salt, sludge, clay and magnetic material may be handled to be cleaned. The magnetic material may come from drilling equipment and from the bedrock. Accordingly, the apparatus herein may be utilized to remove said magnetic material from said liquid. The apparatus may be at a final step of the cleaning process.

[0010] The present disclosure is at least partly based on the insight that a magnetic filter apparatus which comprises a driving means arranged to drive a plurality of at least partly magnetic rods along a loop to capture magnetic particles is more efficient compared to magnetic filters of the previous art as the filter apparatus continuously is able to capture magnetic particles from a liquid.

[0011] The present disclosure provides a magnetic filter for separating magnetic particles from a liquid, specifically, the apparatus is suitable for use in off-shore drilling operations so separate magnetic particles from liquid that has been contaminated during the drilling operation.

[0012] The magnetic filter apparatus comprises a plurality of rods, each rod having at least one magnetic portion, each rod extending parallel to a lateral axis of said magnetic filter apparatus. Further, the magnetic filter apparatus comprises a driving means arranged to drive each of the plurality of rods in a loop continuously (i.e. endlessly, while in a filtering state). Further, the apparatus comprises a removal device arranged to remove captured magnetic particles from each rod of the plurality of rods. The loop defines a trajectory having a lower portion and an upper portion (which jointly may form a closed geometric form, such as an oval circle) wherein the lower portion is arranged to be immersed in liquid. Further, the driving means is arranged to drive the plurality of rods to enable / control each rod to, when being in the lower portion, be immersed in said liquid for an (pre-defined) initial time-period to capture said magnetic particles. In other words, the driving means may adapt a speed thereof to allow each rod to be immersed for a pre-defined initial time-period. Advantageously, as the plurality of rods are traveling along the loop, each rod is able to capture magnetic particles, which are subsequently removed by the removal device. Further, after having any captured particles removed, each rod again move along the loop to capture particles again. As the apparatus comprises a plurality of rods, the rods may be arranged to allow the removal device to continuously and iteratively remove magnetic particles from the rods.

[0013] It should be noted that the removal device may be a single removal device.

[0014] Further, the upper portion may preferably be vertically elevated relative to the lower portion. Advantageously, allowing natural discharge of liquid from each rod after the rods have moved past the lower portion.

[0015] The loop may define any suitable trajectory, preferably in the form of a closed-loop trajectory. The trajectory may be circular, rectangular or have any other suitable form. Preferably, the trajectory is an elongated oval having opposite curve portions adjoined by two linear portions. Preferably, one of the curve portions is said lower portion. Also, preferably, the removal device is located at the opposite curve portion or at one linear portion which is downstream of said curve being in the lower portion so to facilitate natural discharge of liquid from captured magnetic substance for as long as possible.

[0016] Each rod may extend parallel to said lateral axis of said magnetic filter apparatus throughout said loop. An advantage of this is that each rod may be utilized optimally to capture magnetic particles / substance. Each rod may, when being in said lower portion, be fully immersed in said liquid. Moreover, each rod may be static along said lateral axis throughout said loop such that none of the rods will be displaced along the lateral axis throughout said loop.

[0017] Each rod may comprises a plurality of magnetic / magnetized portions, each magnetic portion being interleaved with a non-magnetic portion, wherein end portions of each rod comprises non-magnetic portions. Each rod may have a circular cross-section. Each magnetic portion may be designed to attract magnetic particles / substance from the liquid, e.g. steel. The magnetic portions may each be permanent magnetic portions. Preferably comprising neodymium magnets. The rod may have (excluding the end portions) at least three magnetic portions and at least three non-magnetic portions, or at least four non-magnetic portions, or at least four magnetic portions, or more.

[0018] An advantage of having a rod with magnetic portions being interleaved with non- magnetic / non-permanent magnetic portions is that it allows the removal device to remove the magnetic substance more efficiently. For example, if the whole rod is magnetic, the removal device may struggle to provide force to overcome a magnetic field (as the removal device may also comprise components / parts that are magnetic, such as steel). The magnetic portions may be interleavingly arranged with the non-magnetic portions along the length of each rod. Moreover, end portions of each rod may comprise non-magnetic portions. An advantage of this is that it allows the magnetic device to efficiently remove magnetic substance from a rod by circumferentially stroking a rod from one of the ends to the opposite end. If each end is free from magnetic material, the removal device can initiate removal more efficiently from one of the ends. Also, at an end of the stroke of the removal device, the risk of removed magnetic substance to be "re-captured" by the rod is mitigated if the other end is also non-magnetic.

[0019] In some aspects herein, the term "magnetic" may refer to "permanent magnetic" while "nonmagnetic" may refer to non-permanent magnetic materials and / or a material that does not exhibit any magnetism so to not respond to a magnetic field, e.g. aluminium, and most plastics. Le. non-magnetic may in some aspects be a material that only excludes permanent magnets.

[0020] A distance / gap between adjacent magnetic portions may be at least 10 mm. Preferably, below 30mm to most efficiently capture magnetic substance while maintaining efficiency during removal. The end portions of each rod that are non-magnetic may be at least 10 mm long along the lateral axis, preferably at least 30 mm long. Preferably, one of the ends, associated with an end of the stroke of the removal device, has a length of at least 20 mm, preferably about 30 mm. Each rod may have a diameter of at least 10mm. In some aspects the diameter may be between 10 mm-100 mm, preferably 10 mm-50 mm, more preferably 10-40 mm. The length of each rod may differ depending on the width of a reservoir from which said rod is designed to capture the magnetic substance from. E.g. if the reservoir has a length, A and a width, B, wherein the liquid flows along the length. The rod may have a length of at least 50%, preferably at least 70% of the width B. Accordingly, the rod may have its lateral extension parallel to the width B when the apparatus is placed in the reservoir.

[0021] Any component of the apparatus may be formed by any suitable material, preferably steel, aluminium and antistatic plastic materials. The apparatus may be pneumatically driven to conform with requirements of EX classified environments.

[0022] The rods may be attached to, and distributed throughout a perimeter of said drive band. In some aspects, the rods are substantially evenly distributed throughout said perimeter. The rods may be distributed so that there is a distance or gap of at least 20mm between adjacent rods. Preferably, between 10-40 mm. However, the gap may be less than 150 mm. An advantage of having a gap of between 10-40mm is that any substance material flowing between two adjacent rods may be attracted to one of the rods.

[0023] The driving means may be arranged to drive the plurality of rods in said loop continuously at a constant rate, by stepwise movement. The constant rate may allow each rod to be immersed for an equal amount of time in the liquid. The stepwise movement enables the removal device to operate more conveniently. The removal device may be configured to be synchronized relative the movement of the driving means. Accordingly, the stepwise movement may comprise a moving state in which the drive band is moving, and a stop state in which the drive band is sti ll / static. Hence, the removal device may be configured to operate (so to grip a rod and move linearly along a length thereof) upon said stop state and be passive relative to the band in said moving state. In other words, each time a stop state occurs, the removal device may perform a first movement, the first movement comprising to circumfere / embrace a rod. Further, at said stope stat the removal device may perform a second movement which comprises movement linearly along the lateral axis to stroke the length of the rod. The first movement may be performed radially with respect to the rod. The first movement may therefore be a linear movement of the removal device (perpendicular to an axial extension of the rod) in which removal device has two gripping units which move linearly, and radially relative to the rod from a first to a second position. In the first position, the gripping units are spaced apart from the rod from e.g. opposite sides of the rod. In the second position the gripping units embrace the rod so to fully circumfere the rod. Thus, the gripping units may be in contact in the second position. Thus, the gripping units may be fixed with a common orientation.

[0024] It should be noted that even though the driving means drive the rods at a constant rate, the rate may be adjusted by an operator or automatically by the apparatus. The apparatus may have a user input means for receiving user inputs regarding the speed of the drive means. The speed may be adapted, manually or automatically, dependent on the amount of magnetic substance in the liquid.

[0025] The removal device may be located at a distance from said lower portion, wherein the driving means may be arranged to drive the plurality of rods at a constant rate to enable each rod to naturally discharge liquid for at least a secondary time-period after moving past said lower portion. The secondary time-period may be e.g. more than 1 minute, more than 2 minutes, more than 5 minutes or more than 10 minutes.

[0026] The removal device may comprise a gripper, the gripper being arranged to circumferentially grip a rod at one end portion and slide / stroke (while abutting the rod) along a length thereof, to an opposite end portion so to remove said captured magnetic particles from said rod. The apparatus may comprise a sump arranged to receive the magnetic particles removed from the rod.

[0027] An advantage of this is that the gripper efficiently removes any magnetic particles from each rod.

[0028] The removal device may perform a linear movement along the length of the rod to remove magnetic particles therefrom.

[0029] The gripper may comprises a lateral extension being less than 30% of a length of each rod, wherein the gripper comprises a first and a second part arranged to jointly grip each rod so to jointly encircle a rod. Thereby, as the gripper moves along the rod, any magnetic particles captured by the rod will be removed from the rod circumference. As noted herein, the gripper may be configured to be synchronized / harmonized with a stepwise movement of the drive band so to efficiently remove magnetic substance from each rod. In other aspects, the apparatus may comprise sensor devices, wherein the gripper moves based on a control signal generated based on said sensor device. Le. the sensor device may provide sensor data indicative of that a rod has entered a gripping zone.

[0030] The present disclosure further provides a filtering system for separating magnetic particles from a liquid. The filtering system comprises a reservoir arranged to receive an amount of liquid containing magnetic particles. Further, the system comprises the magnetic filter apparatus according to any aspect herein. The reservoir may have a width being parallel to said lateral axis. The magnetic filter apparatus may extend along said lateral axis to at least 80% of said width. Further, the magnetic filter apparatus may be placed in said reservoir so that said lower portion of said trajectory is immersed in said liquid. Further, the system is configured to: drive each of the plurality of rods in said loop continuously to allow the plurality of rods to capture said magnetic particles from said liquid in said reservoir; remove, by said removal device, captured magnetic particles from each rod.

[0031] The system may drive the rods in said loop clockwise or anti-clockwise.

[0032] The reservoir may have an inlet and an outlet. The apparatus may be positioned in the reservoir between the inlet and the outlet. The liquid may flow from the inlet via the apparatus and to the outlet where at least a portion of the magnetic particles of the liquid is removed therefrom. The liquid may flow with a rate of at least 2 liters per minute.

[0033] The removal device may be stationary, so that it only performs a linear movement along a length of each corresponding rod. Hence, the removal device may be located at a part of said trajectory so that each rod passes the removal device in order to circulate the trajectory (i.e. a full turn). BRIEF DESCRIPTION OF THE DRAWINGS

[0034] These and other features and advantages of the present disclosure will now be further clarified and described in more detail, with reference to the appended drawings;

[0035] Figure 1 illustrates an objective view of a magnetic filter apparatus in accordance with some aspects of the present disclosure;

[0036] Figure 2 illustrates a side cross-sectional view of a magnetic filter apparatus in accordance with some aspects of the present disclosure;

[0037] Figure 3 illustrates a front view of a rod before and after capturing magnetic substance in accordance with some aspects of the present disclosure;

[0038] Figure 4 illustrates a side view of a magnetic filter apparatus with an enlarged view A in accordance with some aspects of the present disclosure;

[0039] Figure 5 illustrates an objective view of a removal device in accordance with some aspects of the present disclosure;

[0040] Figure 6 illustrates a side view of a trajectory which each of the plurality of rods may follow in accordance with some aspects of the present disclosure; and

[0041] Figure 7 illustrates a system from a front view in accordance with some aspects of the present disclosure.

[0042] DETAILED DESCRIPTION

[0043] In the following detailed description, some embodiments of the present disclosure will be described. However, it is to be understood that features of the different embodiments are exchangeable between the embodiments and may be combined in different ways, unless anything else is specifically indicated. Even though in the following description, numerous specific details are set forth to provide a more thorough understanding of the present disclosure, it will be apparent to one skilled in the art that the present disclosure may be practiced without these specific details. In other instances, well known constructions or functions are not described in detail, so as not to obscure the present disclosure. It is also to be understood that the terminology used herein is for purpose of describing particular aspects only, and is not intended to be limiting. It should be noted that, as used in the specification and the appended claim, the articles "a", "an", "the", and "said" are intended to mean that there are one or more of the elements unless the context clearly dictates otherwise. Thus, for example, reference to "a unit" or "the unit" may refer to more than one unit in some contexts, and the like. Furthermore, the words "comprising", "including", "containing" do not exclude other elements or steps. It should be emphasized that the term "comprises / comprising" when used in this specification is taken to specify the presence of stated features, integers, steps, or components. It does not preclude the presence or addition of one or more other features, integers, steps, components, or groups thereof. The term "and / or" is to be interpreted as meaning "both" as well and each as an alternative. More specifically, the wording "one or more" of a set of elements (as in "one or more of A, B and C" or "at least one of A, B and C") is to be interpreted as either a conjunctive or disjunctive logic. Put differently, it may refer either to all elements, one element or combination of two or more elements of a set of elements. For example, the wording "A, B and C" may be interpreted as A or B or C, A and B and C, A and B, B and C, or A and C.

[0044] It will also be understood that, although the term first, second, etc. may be used herein to describe various elements or features, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the embodiments. The first element and the second element are both elements, but they are not the same element.

[0045] Various embodiments of the present disclosure will be described in detail with reference to the drawings, wherein like reference numerals represent like parts and assemblies throughout the several views. Various directions and orientations, such as "upward," "downward," "top," "bottom," "upper," "lower", etc. are generally described herein with reference to the drawings in the usual gravitational frame of reference, regardless of how the components may be oriented.

[0046] Figure 1 illustrates an objective view of a magnetic filter apparatus 1 for separating magnetic particles (not shown, see Figure 3) from liquid (not shown, see Figure 7). The apparatus 1 of Figure 1 comprises a plurality of rods 2, each rod 2 having at least one magnetic portion, each rod 2 extending parallel to a lateral axis xl of said magnetic filter apparatus 1. Further, the apparatus 1 comprises a driving means 3 arranged to drive each of the plurality of rods 2 in a loop continuously. The apparatus 1 may be dimensioned to be stationary on a surface, accordingly, the apparatus 1 may as illustrated in Figure 1 comprise a standing platform 16 arranged to be on a surface. Hence, as illustrated the apparatus 1 extends vertically along a second axis x2 from said standing platform 16.

[0047] Moreover, the apparatus 1 as illustrated in Figure 1 comprises a plurality of rods, e.g. 10-20 rods 2. The rods 2 are parallel to each other, wherein adjacent rods are spaced apart along said second and / or third axis x2, x3 (parallel to their axial extension). Further, Figure 1 illustrates that the rods 2 are not displaced relative each other along the lateral axis xl. Also, the rods 2 as illustrated, may have an equal length and equal diameter, so that each of the plurality of rods 2 are identical.

[0048] Figure 2 illustrates a side-cross sectional view of the apparatus 1 of Figure 1. Figure 2 illustrates that the apparatus 1 comprises a removal device 4 arranged to remove captured magnetic particles from each rod 2.

[0049] Moreover, Figure 2 illustrates that the loop defines a trajectory having a lower portion ul and an upper portion u2, wherein the lower portion ul is arranged to be immersed in liquid. Moreover, Figure 2 illustrates a driving means 3 arranged to drive the rods 2 to enable each rod 2 to, when being in the lower portion ul, be immersed in said liquid 10b for an initial timeperiod to capture said magnetic particles. The initial time-period may differ depending on how contaminated the liquid is of magnetic particles. Le. the initial time-period may be 1-20 minutes such that each rod is in said lower portion ul for 1-20 minutes.

[0050] Figure 2 illustrates that the drive means 3 is arranged to drive the rods, which may form a series of rods 2, along a trajectory which is oval, clockwise. Nonetheless, the trajectory may have any other suitable shape. Figure 2 illustrates that the trajectory is oval wherein the trajectory has two curved portions adjoined by two linear portions. Figure 2 comprises dashed arrows indicating the clockwise motion of the rods 2. Moreover, Figure 2 illustrates that eight rods 2 are in said lower portion ul, however the amount of rods 2 in said lower portion may differ.

[0051] Figure 2 further illustrates that the driving means 3 may comprise a drive band structure 3a forming a perimeter, said perimeter defining said trajectory. The drive band structure 3a in Figure 2 comprises a chain structure which is wound about an actuating arrangement 3b in the form of a gear arrangement. Accordingly, Figure 2 illustrates that the plurality of rods 2 are distributed along said drive band structure 3a, wherein the actuating arrangement 3b is arranged to circulate the drive band structure 3a, thereby driving each of the plurality of rods 2 in said loop. In Figure 2, the gear arrangement comprises at least two gears displaced by a distance. Le. the two are arranged to be displaced in a manner to allow the chain to be wrapped therearound with a tension allowing the gears to drive the chain structure endlessly in a loop along said trajectory. The drive band structure 3a may be any other suitable structure so it is not limited by a chain structure. The drive band structure 3a may have attachment means for receiving the rods 2 so that the rods 2 are driven by the drive band structure 3a. It should be noted that the drive band structure 3a may drive each rod 2 from opposite ends / end portions of each rod 2. This visible in Figure 1 where it is illustrated that the actuating arrangement 3b, in the form of a chain structure comprises two chains displaced along the lateral axis xl, each associated with a corresponding end of each rod 2.

[0052] Hence, the gear arrangement may be pair-wise configurated (e.g. as shown in Figure 1) so that there are four gears, wherein two of the gears are connected at opposite ends of a common drive shaft and the other two are connected by opposite ends of a common other drive shaft. Nonetheless, it should be appreciated that the gear arrangement and the chain structure may be configurated in any other way which also allows the drive band structure 3a to drive the rods 2 in a loop along said trajectory.

[0053] As illustrated in Figure 2 the rods 2 may be attached to, and distributed throughout said perimeter of said drive band structure 3a. In Figure 2 the rods are 2 evenly distributed throughout said perimeter. Each rod 2 may be distanced from an adjacent rod by a distance d, being e.g. 10 mm. It should be noted that the actuating arrangement 3b may also comprise a motor unit (not shown) for providing power to drive the drive band structure 3a. The motor unit may be pneumatic driven by compressed air. The motor unit may have an air compressor, air tank, air lines, control valves and any other suitable unit for allowing the motor unit to convert air to mechanical motion which is supplied to the drive band structure 3a thereby driving the plurality of rods 2.

[0054] The driving means 3 illustrated in Figures 1-2 may be arranged to drive the plurality of rods 2 in said loop continuously, at a constant rate, by stepwise movement. This allows for a more efficient and reliable harmonization with the removal device 4. The step-wise movement may comprise a moving state in which the driving means 3 moves the rods along the trajectory. Further, the step-wise movement may comprise a stop state in which the rods are still. The stop state may be 1-10 minutes long. Accordingly, after 1-10 minutes, the driving means 3 may further move the rods 2 another step. The apparatus 1 may be configured to operate autonomously, once the apparatus is active. In other words, the apparatus 1 may receive an input (by user or automatically) indicative of a speed it should move. Subsequently, the apparatus 1 may loop the rods 2 along the trajectory while removing potentially captured magnetic substance by the removal device 4 autonomously without any further input. To allow this, the movement of the removal device 4 may be harmonized / clock-synchronized with the movement of the rods 2 along the trajectory so to allow for said autonomous operation. Hence, after the apparatus 1 is activated, a flow of liquid may be supplied via the apparatus 1 i.e. so to flow along the third axis x3 through the rods 2. In some aspects the apparatus 1 may autonomously be configured to adapt a speed (of moving the rods) based on the flow of liquid and / or a level of contamination of the liquid (which may be read by sensor devices).

[0055] Figure 3 illustrates a single rod 2 from a front view, in two states, before being immersed in liquid and one after being immersed in liquid. Figure 3 illustrates that after being immersed in liquid the rod 2 has captured magnetic substance 10a.

[0056] Figure 3 illustrates that the magnetic substance 10a is captured interleavingly along the axial length of the rod 2 which occur by that the rod 2 of Figure 3 comprises a plurality of magnetic portions 2a, each magnetic portion 2a being interleaved with a non-magnetic portion 2b (formed by e.g. aluminum), wherein end portions el, e2 of each rod 2 comprises nonmagnetic portions 2b. The magnetic portions 2a may be separated by a pre-determined distance to allow magnetic substance 10a to be captured efficiently without hampering / adversely affecting the motion of the removal device when cleaning / rinsing the substance 10a off of the rod 2. Preferably, an end portion el, e2 associated with an end of the stroke of the removal device may have a longer non-magnetic portion 2a than the end associated with a start of the stroke of the removal device. The term "stroke" may refer to a motion performed by the removal device which is linear and allows any magnetic substance on a rod 2 to be removed.

[0057] Figure 4 illustrates a side view of the apparatus 1 with an enlarged view A that emphasized the removal device 4. In Figure 4 it is illustrated that the removal device 4 is located at a distance from said lower portion ul to allow for natural discharge of liquid for a time-period after magnetic substance is captured by each rod 2. Figure 4 illustrates that the removal device 4 may comprise a gripper, the gripper being arranged to circumferentially grip a rod 2 at one end portion el and slide along a length thereof, to an opposite end portion e2 so to remove said captured magnetic particles 10a from said rod 2. Accordingly, Figure 4 illustrates that the gripper comprises a first and a second part 4a, 4b arranged to oppositely grip each rod 2 at one end and stroke the rod throughout its length to remove any magnetic particles.

[0058] Figure 5 illustrates an objective view of a removal device 4 relative a rod 2. Figure 5 illustrates that the removal device 4 may be arranged to (as indicate by arrows) grip the rod 2 circumferentially and further (as indicated by the dashed arrow) stroke along a length of the rod 2 to allow any magnetic substance to be removed from the rod 2. The end of the stroke motion may be associated with a sump arranged relative the rod 2 to receive magnetic substance which is removed from the rod 2.

[0059] Figure 6 illustrates a side view of the trajectory which is defined by the driving means 3. Figure 6 illustrates that the trajectory is oval, wherein the trajectory comprises a first curve part, a second curve part cl, c2 adjoined by a first and a second linear connecting line al, a2 so to form a closed trajectory. Preferably, the connecting lines extend along a traveling axis ml which is angled relative to the second and third axis x2, x3 of the apparatus (i.e. nonparallel with either of x2 and x3. The second axis x2 extending vertically. In other words, the connecting lines al, a2 may be tilted vertically by e.g. 5-85 degrees, preferably 20-70 degrees, more preferably 20-60 degrees. An advantage of this is that it allows the rods, which are distributed throughout the trajectory to form a grid-like structure to efficiently capture any magnetic substance flowing through the apparatus. For example, if the lines al, a2 are parallel with either of axis x2 and x3 the apparatus 1 will capture magnetic substance less efficiently compared to the orientation of Figure 6. As apparent, the portions al, a2, cl, c2 jointly form the perimeter of said trajectory and the rods move in the loop through said trajectory. The term "loop" may refer to that the apparatus is configured to drive each rod throughout the trajectory for more than one turn.

[0060] Figure 7 illustrates a front view of a filtering system 100 for separating magnetic particles from liquid 10b, the system 100 comprising a reservoir 110 arranged to receive an amount of liquid 10a containing magnetic particles. Further, the system 100 comprises a magnetic filter apparatus 1, the magnetic filter apparatus 1 being placed in said reservoir 100 so that said lower portion of said trajectory is immersed in said liquid 10a. Moreover, the system 100 is configured to: drive each of the plurality of rods 2 in said loop continuously to allow the plurality of rods 2 to capture said magnetic particles from said liquid 10b in said reservoir 110; and remove, by said removal device 4, captured magnetic particles from each rod 2.

[0061] The liquid may flow through the reservoir 110 via the apparatus 1. The width of the reservoir

[0062] 110 may be substantially equal to the width of the rods e.g. 5-20% wider than each rod.

Claims

CLAIMS1. A magnetic filter apparatus (1) for separating magnetic particles (10a) from liquid (10b) comprising: a plurality of rods (2), each rod (2) having at least one magnetic portion (2a), each rod (2) extending parallel to a lateral axis (xl) of said magnetic filter apparatus (1); a driving means (3) arranged to drive each of the plurality of rods (2) in a loop; a removal device (4) arranged to remove captured magnetic particles from each rod (2); wherein the loop defines a trajectory having a lower portion (ul) and an upper portion (u2), wherein the lower portion (ul) is arranged to be immersed in liquid (10b), wherein the driving means (3) is arranged to drive the rods (2) to enable each rod (2) to, when being in the lower portion (ul), be immersed in said liquid (10b) for an initial time-period to capture said magnetic particles (10a).

2. The magnetic filter apparatus (1) according to claim 1, wherein each rod (2) extends parallel to said lateral axis (xl) of said magnetic filter apparatus (1) throughout said loop.

3. The magnetic filter apparatus (1) according to claim 1 or 2, wherein each rod (2) comprises a plurality of magnetic portions (2a), each magnetic portion (2a) being interleaved with a non-magnetic portion (2b), wherein end portions (el, e2) of each rod (2) comprises non-magnetic portions (2b).

4. The magnetic filter apparatus (1) according to any one of the preceding claims, wherein the driving means (3) comprises: a drive band structure (3a) forming a perimeter, said perimeter defining said trajectory; an actuating arrangement (3b); wherein the plurality of rods (2) are distributed along said drive band structure (3a), wherein the actuating arrangement (3b) is arranged to circulate the drive band structure(3a), thereby driving each of the plurality of rods (2) in said loop.

5. The magnetic filter apparatus (1) according to claim 4, wherein the rods (2) are attached to, and distributed throughout said perimeter of said drive band structure (3a), preferably evenly distributed throughout said perimeter.

6. The magnetic filter apparatus (1) according to any one of the preceding claims, wherein said driving means (3) is arranged to drive the plurality of rods (2) in said loop continuously, at a constant rate, by stepwise movement.

7. The magnetic filter apparatus (1) according to any one of the preceding claims, wherein said removal device is located at a distance from said lower portion (ul), wherein the driving means (3) is arranged to drive the plurality of rods (2) at a constant rate to enable each rod to naturally discharge liquid for at least a secondary timeperiod after moving past said lower portion (ul).

8. The magnetic filter apparatus (1) according to any one of the preceding claims, wherein the removal device (4) comprises a gripper, the gripper being arranged to circumferentially grip a rod (2) at one end portion (el) and slide along a length (LI) thereof, to an opposite end portion (e2) so to remove said captured magnetic particles (10a) from said rod (2).

9. The magnetic filter apparatus (1) according to claim 8, wherein the removal device comprises a lateral extension being less than 30% of a length of each rod, wherein the removal device comprises a first and a second part (4a, 4b) arranged to jointly grip each rod (2).

10. A filtering system (100) for separating magnetic particles (10a) from liquid (10b) comprising: a reservoir (110) arranged to receive an amount of liquid (10a) containing magnetic particles (10b);the magnetic filter apparatus (1) according to any one of the claims 1-9, the magnetic filter apparatus (1) being placed in said reservoir (100) so that said lower portion (ul) of said trajectory is immersed in said liquid (10a); wherein the system (100) is configured to: - drive each of the plurality of rods (2) in said loop continuously to allow the plurality of rods (20) to capture said magnetic particles (10a) from said liquid (10b) in said reservoir (110); remove, by said removal device (4), captured magnetic particles from each rod (2).

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