A drainage arrangement for an air filter assembly and an air filter assembly

Abstract

The disclosure relates to a drainage arrangement (1) for an air filter assembly (100), the drainage arrangement (1) being configured to be arranged at an airflow inlet (200) of the air filter assembly (100) to allow liquid that has accumulated inside the air filter assembly (100) to exit, the drainage arrangement (1) comprising: a shield element (10) comprising a deflector section (12) configured to deflect an airflow passing through the airflow inlet (2); wherein the shield element (10) is configured to be arranged so that a first passage (30) for the liquid is formed between the deflector section (12) and a bottom plate (600) of the air filter assembly (100), the first passage (30) allowing the accumulated liquid to flow in a direction essentially opposite to the direction of the airflow; and wherein the shield element (10) further comprises an outlet section (14) forming a second passage (40), in which second passage (40) the flow direction of the liquid is essentially perpendicular to the airflow direction, wherein the second passage (40) comprises an outlet aperture (42) for the liquid, the outlet section (14) being connected to the deflector section (12). The disclosure further relates to an air filter assembly (100).

Description

[0001] A drainage arrangement for an air filter assembly and an air filter assembly

[0002] Technical field

[0003] The present disclosure relates to a drainage arrangement for an air filter assembly and an air filter assembly comprising such a drainage arrangement. Specifically, the disclosure relates to a drainage arrangement for an air filter assembly and an air filter assembly as defined in the introductory parts of the independent claims. More specifically, the disclosure relates to a drainage arrangement for a high-volume air filter assembly used in wet or damp conditions.

[0004] Background art

[0005] Air filter assemblies of various kinds are known and they typically comprise some sort of frame structure and at least one filter element mounted within the frame structure. The filter element may comprise a sheet of filter media, which could be pleated to increase the effective filtering area of the filter element. The frame structure may be configured to provide mechanical support to the filter element(s) and also typically forms an airflow inlet for the air to be filtered through the filter element(s).

[0006] Air filter assemblies are used in a wide range of different applications and some filter assemblies are used in wet or damp environments. This is for example the case where the air filter assembly is an inlet filter to a gas turbine for power supply at oil platforms, in coastal areas or on land-based sites with significant precipitation or fog, or any other filter used on oil platforms, ships or similar. In such applications, high volumes of air are filtered to remove both small particles and liquid in order to minimize degradation of the turbine or other equipment. Air filter assemblies used in these types of applications thus require filter elements with a high degree of separation and substantial amounts of water will thereby be separated from the incoming air. The water will typically fall to the bottom of the air filter assembly by gravity and should be drained through the open end of the air filter assembly.

[0007] In order to drain the collected water on the bottom of the air filter assembly, some solutions exist where the frame structure of the air filter assembly comprises a recess in association with the bottom at the open end of the air filter assembly. However, such solutions require the water to flow in a direction opposite to the incoming air in order to be drained, and due to the high volume of incoming air entering through the airflow inlet, the water collected at the bottom of the frame structure will be pushed towards the rear end of the air filter assembly. The water will this way be prevented from draining out through the open end. Water might thereby build-up on the bottom of the air filter assembly which will cause the filter media to soak. The filter media may this way be weakened and this could lead to damages and leakages. Also, the filter media area available for filtering the air will be reduced, which will increase the pressure drop. There is thus a need for an improved drainage arrangement for air filter assemblies.

[0008] It is an object of the present disclosure to mitigate, alleviate or eliminate one or more of the above-identified deficiencies and disadvantages in the prior art and solve at least the above-mentioned problems.

[0009] An object of the present disclosure is thus to provide a drainage arrangement and an air filter assembly, which is suitable for use in wet or damp environments.

[0010] Another object of the present disclosure is to provide a drainage arrangement and an air filter assembly, which facilitates drainage from the air filter assembly and thereby reduces the risk of leakages.

[0011] According to a first aspect there is provided a drainage arrangement for an air filter assembly, the drainage arrangement being configured to be arranged at an airflow inlet of the air filter assembly to allow liquid that has accumulated inside the air filter assembly to exit the air filter assembly, the drainage arrangement comprising: a shield element comprising a deflector section configured to deflect an airflow passing through the airflow inlet; wherein the shield element is configured to be arranged so that a first passage for the liquid is formed between the deflector section and a bottom plate of the air filter assembly, the first passage allowing the accumulated liquid to flow in a direction essentially opposite to the direction of the airflow; and wherein the shield element further comprises an outlet section forming a second passage, in which second passage the flow direction of the liquid is essentially perpendicular to the airflow direction, wherein the second passage comprises an outlet aperture for the liquid, the outlet section being connected to the deflector section.

[0012] By having a shield element that forms a first passage and a second passage, the liquid accumulated in the air filter assembly will be able to flow in a direction opposite to the incoming airflow direction in the first passage and be drained downwards through the second passage while being protected from the incoming airflow entering the air filter assembly. The deflector section is configured to deflect the incoming airflow away from an adjacent area at the bottom plate of the air filter assembly, such that the liquid in that area is not affected by the incoming airflow. The area at the bottom plate protected or covered by the deflector section constitutes the first passage. Thus, the deflector section of the shield element will deflect the incoming airflow away from the first passage and the outlet section will protect the liquid in the second passage. This way, the dynamic pressure caused by the incoming airflow will be prevented from pushing the liquid back into the air filter assembly. Drainage is thereby facilitated and improved, particularly at high airflow speeds. It is to be understood that the liquid may be water. The deflector section and the outlet section are both integrated in the shield element.

[0013] The air filter assembly is typically arranged such that the liquid stopped by the at least one filter element will fall to the bottom plate of the air filter assembly by gravity. The at least one filter element is thus typically vertically arranged. Some filter assemblies are symmetric and can be arranged in different rotational orientations. Thus, an air filter assembly could for example be rotated 180 degrees and function similarly and the liquid would fall to a bottom plate by gravity. In case the air filter assembly is symmetric, the air filter assembly may comprise more than one plate which could constitute the bottom plate of the air filter assembly depending on the rotational orientation of the air filter assembly. In such cases, the air filter assembly may comprise drainage arrangements on more than one side of the air filter assembly and thus in association with more than one bottom plate. This will be further explained below.

[0014] According to the standards EN779 and EN 1822, air filters are categorized in the filter classes Gl, G2, G3, G4, M5, M6, F7, F8, F9, E10, E11,E12, H13, H14, U15, U16, and U17 with increasing filtration efficiency. The air filter assembly may conform to a filtration class from G4 up to H13 according to the standards EN779 or EN 1822 or equivalent other national or international standards. The air filter assembly may conform to a filtration class from F7 up to H13 according to the standards EN779 or EN 1822 or equivalent other national or international standards. The air filter assembly may conform to a filtration class from F9 up to H13 according to the standards EN779 or EN 1822 or equivalent other national or international standards. The air filter assembly may conform to a filtration class from E10 up to H13 according to the standards EN779 or EN 1822 or equivalent other national or international standards. The air filter assembly may conform to a filtration class from ePMlO up to ePMl according to the international standard ISO16890, or from T1 through T13 according to the international standard ISO 29461 -1 . Air filter assemblies according to these filtration classes will typically also remove water droplets present in the air stream. The at least one filter media element of the present disclosure may be impermeable or substantially impermeable to water droplets present in the air stream. Because the filter media element is impermeable or substantially impermeable to water droplets a substantial amount of water will remain on the upstream side of the filter media when the air filter assembly is operated in wet or damp conditions. In some examples, the at least one filter media element is formed of a filter media which does not absorb water, or which only absorbs water to a very low extent. In some examples, the at least one filter media element is formed of a filter media which is hydrophobic. In some examples, the at least one filter media element is formed of a filter media which has high resistance to water penetration. The resistance to water penetration of a filter media may be measured in pascal (Pa) according to the standard EN20811 or ISO811. In some examples, the at least one filter media element has a resistance to water penetration of at least 3000 Pa, at least 4000 Pa, at least 5000 Pa, or at least 6000 Pa, as determined according to the standard EN20811 or ISO811. The filter media element may be a pleated filter media element.

[0015] The shield element is configured such that the first passage transitions into the second passage. The first passage and the second passage extend essentially perpendicularly to each other. The shield element may be configured to be arranged such that the deflector section extends over a part of the bottom plate of the air filter assembly. Thus, the deflector section of the shield element may be configured to extend over a part of the bottom plate of the air filter assembly. The deflector section may be configured to at least partially extend in parallel with the bottom plate. The deflector section may extend from the airflow inlet and into the air filter assembly. In some examples, the deflector section transitions into the outlet section at a point essentially aligned with the front end of the bottom plate. The deflector section extends over the point where the first passage transitions into the second passage. Thus, the deflector section and / or the outlet section are configured to cover the point where the liquid changes direction and falls essentially perpendicularly to the incoming airflow. This way, the liquid to be drained is protected from the incoming airflow all the way from the first passage, into the second passage and down through the second passage, until it is discharged through the outlet aperture.

[0016] The deflector section may be curved, wherein the convex side is configured to face the incoming airflow and the concave side is facing the bottom plate of the air filter assembly. The deflector section may have an aerodynamic shape to minimize pressure drop. The deflector section may be shaped as a hood. In some examples, the deflector section comprises side walls configured to be extending essentially in parallel with the filter media elements arranged on both sides of the drainage arrangement. When the shield element is mounted, the first passage may thus be delimited on one side by the bottom plate and on the remining sides by the deflector section. The first passage may have an essentially tunnel shaped cross-sectional area.

[0017] The air filter assembly may comprise a front frame forming the air inlet into the air filter assembly. The front frame may be referred to as a header frame and is arranged upstream of the at least one filter element and forms at least one airflow inlet into the air filter assembly. The front frame may at least partly encircle the at least one airflow inlet. The front frame may have a rectangular or square shape. The front frame may comprise four elongated beams arranged to form a square or rectangle. The front frame may thus comprise a top beam, a bottom beam and two side beams. The front frame may further comprise front plates extending between the top beam and the bottom beam and being configured to be sealed to the filter media elements.

[0018] The outlet section may be curved, wherein the convex side is configured to face the incoming airflow and the concave side is configured to face the front frame. Alternatively, the outlet section is essentially flat.

[0019] The outlet aperture may be arranged so that the liquid is discharged through the outlet aperture essentially perpendicularly to the incoming airflow direction. In some examples, the outlet aperture is arranged so that the liquid is discharged through the outlet aperture in a direction opposite to the incoming airflow direction.

[0020] The drainage arrangement is suitably configured to be arranged such that the outlet aperture is aligned with, or below, a circumferentially outer side of the front frame of the air filter assembly, the front frame forming at least one airflow inlet. The front frame has a circumferentially outer side and an opposite circumferentially inner side. The front frame also has a front side facing the incoming airflow. The circumferentially inner side faces inwardly towards the at least one airflow inlet, whereas the circumferentially outer side faces away from the air filter assembly. The front frame may be arranged with the circumferentially inner side essentially aligned with the bottom plate of the air filter assembly, or slightly above the bottom plate. Known drainage solutions often comprises a recess in the circumferentially inner side of the front frame, to allow liquid to drain out from the air filter assembly. By arranging the drainage arrangement according to the present disclosure, such that the outlet aperture is aligned with, or below, the circumferentially outer side of the front frame, a water column is created inside the drainage arrangement. The height of the water column extends from the height of liquid inside the first passage to the outlet aperture of the second passage, and thus in this case to the circumferentially outer side of the front frame or beyond. The pressure head of the liquid will add additional force pushing the liquid downwards through the second passage and more efficient drainage is achieved.

[0021] Furthermore, by having the outlet aperture aligned with, or below, the circumferentially outer side of the front frame, the bottom plate can be made to slope downwards towards the second passage. In known solutions where the liquid is drained from the circumferentially inner side of the front frame, a sloping bottom plate will have to be raised at the rear end of the air filter assembly and will this way have a negative effect on the effective filtering area of the filter media element. When the liquid is drained from a lower position, aligned with the circumferentially outer side of the front frame, the bottom plate can be more slanted without affecting the effective filtering area of the filter media element.

[0022] The second passage may be formed by the outlet section of the shield element and the front frame. In some examples, the second passage if formed between the outlet section and a front side of the front frame. In other examples, the second passage is formed between the outlet section and an inner wall section of the front frame.

[0023] The second passage may be laterally inclined in relation to a vertical axis when the drainage arrangement is mounted. The second passage may thus be inclined to the left or the right when being mounted. This way, the drained liquid is prevented from falling straight downwards and the risk of drained liquid entering an air filter assembly positioned below is thereby reduced. Alternatively or additionally, in the event that the air filter assembly comprises drainage arrangements on two opposing sides of the front frame, both at the top of the air filter assembly and at the bottom of the air filter assembly, the second passage of the drainage arrangements at the top may be arranged off-set in relation to the second passage of the drainage arrangements at the bottom. This way, the drainage outlet apertures do not line up when stacking multiple air filter assemblies on each other.

[0024] The first passage may have a first width and the second passage may have a second width. Thus, the deflector section may have a first width and the outlet section may have a second width. The second passage may be tapering in direction away from the first passage and towards the outlet aperture. The first passage may have an essentially constant first width, whereas the second passage may have a varying second width along the length of the second passage. The second width may thus be tapering towards the outlet aperture. The second width at the outlet aperture is typically smaller than the first width of the first passage. This way, the liquid is guided towards the outlet aperture and the drainage is more controlled and focused. Alternatively, the first width and the second width are essentially equal. According to yet another example, the second width of the second passage is diverging in direction towards the outlet aperture. The first width of the first passage may be tapering towards the second passage.

[0025] The drainage arrangement may, according to an example, comprise at least one attachment section configured for snap-fit connection with the air filter assembly. The drainage arrangement may thus be a detachable separate unit which can be retro-fitted to existing air filter assemblies. By having an attachment section configured for snap-fit connection, mounting and demounting of the drainage arrangement is facilitated. The attachment section may be configured to engage with the front frame and / or a front plate of the air filter assembly. The drainage arrangement may comprise two attachment sections, each configured for snap-fit connection with a front plate of the air filter assembly. The attachment section may comprise a snap-fit element configured to engage with an edge of the front frame or with an edge of the front frame. The attachment section may be formed in the deflector section of the shield element. The attachment section(s) may thus be integrated in the shield element. It is to be understood that the attachment section could be configured in many different ways to achieve the snap-fit connection and the illustrated example in this disclosure is solely an example of how it could be configured.

[0026] According to a second aspect there is provided an air filter assembly comprising: a frame structure including a front frame and a bottom plate, and at least one filter media element arranged within the frame structure, the front frame forming at least one airflow inlet into the air filter assembly, wherein the air filter assembly comprises a drainage arrangement according to the first aspect, arranged at the at least one airflow inlet to allow liquid that has accumulated inside the air filter assembly to exit the air filter assembly. The at least one filter media element may be a pleated filter media element.

[0027] It is to be understood that effects and features of the second aspect are to a large extent analogous to those described above in connection with the first aspect. Embodiments mentioned in relation to the first aspect are largely compatible with the second aspect.

[0028] As described above, the front frame may have a rectangular or square shape. The front frame may comprise four elongated beams, a top beam, a bottom beam and two side beams, arranged to form a square or rectangle. The front frame has a circumferentially outer side and an opposite circumferentially inner side. The front frame also has a front side facing the incoming airflow. The circumferentially inner side faces inwardly towards the at least one airflow inlet, whereas the circumferentially outer side faces away from the air filter assembly. The front frame may be arranged with the circumferentially inner side essentially aligned with the bottom plate of the air filter assembly, or slightly above the bottom plate. In some examples, the front frame also comprises integrated front plates configured to seal against the filter media element.

[0029] The bottom plate of the frame structure may also be referred to as a side plate arranged at a bottom of the air filter assembly. It is to be understood that the bottom plate is the plate on which the liquid is accumulated inside the air filter assembly.

[0030] According to an example, the drainage arrangement is detachably connected to the front frame. As mentioned above, the drainage arrangement may be a detachable separate unit, which enables retro-fitting to existing air filter assemblies. It may also facilitate maintenance and service and it will not affect the configuration of the front frame.

[0031] The drainage arrangement may be arranged such that the second passage is upstream of the front frame in the airflow direction. Thus, the drainage arrangement may be arranged with the shield element arranged upstream of the front frame in the airflow direction. As an example, the shield element may be arranged such that the deflector section extends over the bottom plate and the outlet section extends in parallel with the front side of the front frame. In such cases, the second passage may be formed between the outlet section of the shield element and the front frame. More specifically, the second passage may be formed between the outlet section of the shield element and the front side of the front frame.

[0032] According to another example, the drainage arrangement is integrated in the air filter assembly. This way, the risk for leakages is reduced. The drainage arrangement may be integrated in the front frame. The front frame may thus comprise the shield element, including the deflector section extending inwardly into the air filter assembly from the front frame beam. The second passage may comprise a channel in the front frame and the outlet aperture may be formed at the circumferentially outer side of the front frame. The front frame may thus comprise the outlet section of the drainage arrangement.

[0033] In the case where the drainage arrangement is integrated in the air filter assembly, the drainage arrangement may comprise an integrated valve element arranged to block the outlet aperture when drainage is not required. The valve element may be manually controlled between an open state and a closed state. In some examples, the outlet section of the shield element constitutes the valve element. Thus, the outlet section may comprise a flexible material, such as rubber or overmolded thermoplastic, and may be configured to be in an open state or a closed state. The outlet section may be curved or dome-shaped and may be configured to have two stable states, the open state and the closed state. In the open state, the outlet section is typically convex and protrudes out from the front frame, whereby the concave side faces the second passage. In the closed position, the outlet section has been pressed in direction towards the front frame whereby the shape of the outlet section is inverted. This way, the outlet section will close the second passage and the outlet aperture. By closing the outlet aperture, any bypass of air or liquid is prevented.

[0034] In the case where the drainage arrangement is integrated in the air filter assembly, the second passage may be formed by the outlet section and a recess in the front frame, allowing the liquid to flow through the second passage down to a level below the bottom plate. The liquid may thus flow essentially vertically from the first passage, through the second passage down to the bottom of the recess, which is below the level of the bottom plate. The step down from the bottom plate to the bottom of the recess may be at least 10 millimetres. The recess will prevent water from re-entering the air filter assembly. The recess is formed in the bottom beam of the front frame. The outlet aperture is formed by the outlet section being smaller than the recess, thus leaving open areas where the liquid can drain out over the front side of the front frame. This version of the drainage arrangement is particularly suitable for symmetric air filter assemblies because there are no openings in the circumferentially outer side of the front frame and there is less risk for bypass of air or liquid even without a valve element. The drainage arrangement may further comprise at least two guiding elements, also referred to as guiding fins, arranged in association with the shield element. The guiding elements are arranged in the recess in the front frame. Typically, a plurality of guiding elements is arranged on both sides of the shield element in the recess. The guiding elements are configured to guide the incoming airflow laterally to the sides of the at least one airflow inlet. This way, the guided airflow will have minimal impact on the liquid drained from the air filter assembly. Also, the guided airflow will help moving the liquid in the recess laterally, away from where it is shielded by the outlet section to the outlet apertures where it is easy for it to fall out of the front side of the front frame. The guiding elements may be integrated in the front frame or in the bottom plate.

[0035] The bottom plate of the air filter assembly may be sloping towards the second passage and / or be through-shaped. This way, the drainage is improved. The bottom plate being trough-shaped means that it has an essentially v-shaped cross-sectional shape. The bottom plate may thus comprise side walls slanting towards the centre of the bottom plate.

[0036] The air filter assembly may be a V-type filter assembly. A V-type filter assembly typically includes at least two pleated filter media elements arranged in a V-configuration.

[0037] The air filter assembly will herein be described as a V-type filter assembly but it is to be understood that the inventive drainage arrangement as disclosed herein also could be used in panel filter assemblies.

[0038] In the event that the air filter assembly is a V-type filter assembly, it comprises at least two pleated filter media elements arranged in a V configuration having an open end and a closed end in the airflow direction. The V configuration also has a top and bottom V-shaped end. The open end may be referred to as an upstream end and the closed end may be referred to as a downstream end. The open end of the V configuration is arranged at a front of the air filter assembly, and the closed end of the V configuration is arranged at a rear end of the air filter assembly. The front frame is arranged at the open end of the V configuration. The frame structure may comprise the front frame, at least one rear plate sealed to the filter media elements at the closed end, and two side plates sealed to the V-shaped ends of the V configuration. The two side plates are thus sealed against the pleated ends of the filter media elements. The two side plates may constitute bottom plates depending on the rotational orientation of the air filter assembly. The front frame may further comprise front plates sealed to the filter media elements at the open end. The front plates extend longitudinally between the top beam and the bottom beam of the front frame. In the event that the V-type air filter assembly comprises a plurality of V configurations, the frame structure comprises a plurality of rear plates and a plurality of front plates. The air filter assembly will also comprise a plurality of airflow inlets formed between the top beam, the bottom beam and the front plates of the front frame. The incoming airflow will enter through the airflow inlet(s) and through the open end of the V configuration(s). Since the V configuration has a closed downstream end, the air will flow through the filter media element in a direction essentially perpendicular to the incoming airflow direction and out from the air filter assembly.

[0039] It is to be understood that a side plate sealed against a pleated (zig-zag) edge of the filter media element, irrespective of the air filter assembly being a panel filter or a V-type filter, may constitute the bottom plate of the invention. Having the filter media element(s) arranged with the pleats (folds) vertically oriented during use improves drainage from the filter media element. The straight, non-pleated edges of the pleated filter media elements may be sealed to the other pair of opposing side plates in the case of a panel filter assembly or to front plates and rear plates in the case of a V-type filter assembly.

[0040] The drainage arrangement and air filter assembly according to the present disclosure are specifically advantageous for high airflow application with high filtration requirements. In such applications, it is important to minimize obstruction of the airflow and thereby minimize pressure drop. The drainage arrangement is therefore configured to leave the at least one airflow inlet as unobstructed as possible.

[0041] The unobstructed cross-sectional area of the at least one airflow inlet is at least 90 %, preferably at least 95%. In other words, the drainage arrangement blocks no more than 10 %, preferably no more than 5%, of the cross-sectional area of the at least one airflow inlet. In order to minimize obstructions of the airflow and resulting pressure drop, the cross-sectional area of the at least one airflow inlet is preferably free from other obstructions besides the drainage arrangement(s). In the examples where the bottom plate is sloping downwards, the drainage arrangement can be moved below the level of the filter media element(s) and the drainage arrangement will thereby add even less obstruction to the incoming airflow.

[0042] The present disclosure will become apparent from the detailed description given below. The detailed description and specific examples disclose preferred embodiments of the disclosure by way of illustration only. Those skilled in the art understand from guidance in the detailed description that changes and modifications may be made within the scope of the disclosure.

[0043] Hence, it is to be understood that the herein disclosed disclosure is not limited to the particular component parts of the device described or steps of the methods described since such device and method may vary. It is also to be understood that the terminology used herein is for purpose of describing particular embodiments 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 explicitly dictates otherwise. Thus, for example, reference to "a unit" or "the unit" may include several devices, and the like. Furthermore, the words "comprising", "including", "containing" and similar wordings does not exclude other elements or steps.

[0044] Brief of the The above objects, as well as additional objects, features and advantages of the present disclosure, will be more fully appreciated by reference to the following illustrative and non-limiting detailed description of example embodiments of the present disclosure, when taken in conjunction with the accompanying drawings.

[0045] Figure 1 schematically shows an air filter assembly according to an example of the present disclosure.

[0046] Figures 2a-c schematically show a drainage arrangement according to examples of the present disclosure.

[0047] Figures 3a-c schematically show a drainage arrangement according to examples of the present disclosure.

[0048] Figures 4a-d schematically show drainage arrangements according to examples of the present disclosure.

[0049] Figures 5a-b schematically show details of an air filter assembly according to examples of the present disclosure.

[0050] Figures 6 schematically show a drainage arrangement according to examples of the present disclosure.

[0051] Figure 7 schematically shows an air filter assembly according to an example of the present disclosure.

[0052] Detailed description

[0053] The present disclosure will now be described with reference to the accompanying drawings, in which preferred example embodiments of the disclosure are shown. The disclosure may, however, be embodied in other forms and should not be construed as limited to the herein disclosed embodiments. The disclosed embodiments are provided to fully convey the scope of the disclosure to the skilled person.

[0054] Figure 1 schematically shows an air filter assembly 100 according to an example of the present disclosure. The air filter assembly 100 comprises a frame structure 400 including a front frame 500 and a bottom plate 600, and at least one filter media element 700 arranged within the frame structure 400. The front frame 500 is forming at least one airflow inlet 200 into the air filter assembly 100. The air filter assembly 100 comprises a drainage arrangement 1 as described in any of the following figures, arranged at the at least one airflow inlet 200 to allow liquid that has accumulated inside the air filter assembly 100 to exit the air filter assembly 100. Specifically, the drainage arrangement 1 is arranged to drain liquid that has accumulated at the bottom plate 600.

[0055] Figure 1 shows a V-type filter assembly 100. The V-type filter assembly 100 comprises at least two pleated filter media elements 700 arranged in a V configuration having an open end 710 and a closed end 720 in the airflow direction. The V configuration also has a top and a bottom V-shaped end 731, 732. The open end 710 is arranged upstream of the closed end 720. The air filter assembly 100 in this example comprises three V configurations as shown in this figure.

[0056] The frame structure 400 comprises the front frame 500, three rear plates 410 sealed to the filter media elements 700 at the closed end 720, and two side plates 420 sealed to the V- shaped ends 731, 732 of the V configurations. The front frame 500 is arranged at the open end 710 of the V configuration and thus at the front end of the air filter assembly 100. The front frame 500 comprises four elongated beams 501 arranged to form a square or rectangle, a top beam, a bottom beam and two side beams. The front frame 500 has a circumferentially outer side 510 and an opposite circumferentially inner side 520. The front frame 500 also has a front side 530 facing the incoming airflow illustrated by an arrow. The front frame 500 is typically arranged with the circumferentially inner side 520 essentially aligned with the bottom plate 600 of the air filter assembly 100. The two side plates 420 are connected to the front frame 500 and constitute bottom plates 600 depending on the rotational orientation of the air filter assembly. The rear plates 410 extend longitudinally between the two side plates 420 and are connected to the two side plates 420. The front frame 500 further comprises four front plates 430 sealed to the filter media elements 700 at the open end 710. The front plates 430 extend longitudinally between the top beam 501 and the opposing bottom beam 501 of the front frame 500. When the air filter assembly 100 is arranged with the filter media elements 700 arranged vertically as shown in the figure, the front plates 430 extend vertically between the top beam 501 and the bottom beam 501 of the front frame 500.

[0057] The air filter assembly 100 will this way comprise three airflow inlets 200, formed by the front frame 500. Each airflow inlet 200 is essentially rectangular and comprises a part of the top and bottom beams 501 at the short ends of the rectangle and front plates 430 at the long sides of the rectangle. A drainage arrangement 1 is arranged at each airflow inlet 200. More specifically, a drainage arrangement 1 is arranged in association with the bottom plate 600 and the front frame 500 at each airflow inlet 200. The drainage arrangements 1 are arranged at the bottom beam 501 of the front frame 500. In the example shown in this figure, the drainage arrangements 1 are removably connected to the front plates 430. However, it is to be understood that the drainage arrangements 1 could be integrated in the front frame 500 of the air filter assembly 100.

[0058] Figures 2a-c show a drainage arrangement 1 for an air filter assembly 100 according to examples of the present disclosure. The air filter assembly 100 may be configured as in Figure 1. The drainage arrangement 1 is configured to be arranged at an airflow inlet 200 of the air filter assembly 100 to allow liquid that has accumulated inside the air filter assembly 100 to exit the air filter assembly 100. The drainage arrangement 1 in Figures 2a-c is a separate unit, configured to be removably attached to the air filter assembly 100.

[0059] The drainage arrangement 1 comprises a shield element 10 with a deflector section 12 configured to deflect an airflow passing through the airflow inlet 200. In Figures 2a-b the incoming airflow being deflected by the deflector section 12 is illustrated as black arrows. The shield element 10 is configured to be arranged so that the deflector section 12 extends over a bottom plate 600 of the air filter assembly 100. A first passage 30 for the liquid is thereby formed between the deflector section 12 and the bottom plate 600 of the air filter assembly 100. The first passage 30 allows the accumulated liquid to flow in a direction essentially opposite to the direction of the airflow. Thus, the deflector section 12 will prevent the incoming airflow from affecting the liquid in the first passage 30. The shield element 10 further comprises an outlet section 14 forming a second passage 40. In the second passage 40 the flow direction of the liquid is essentially perpendicular to the airflow direction. The second passage 40 is configured to drain the liquid downwards and the downward drain direction of the liquid is illustrated by a black arrow. The second passage 40 comprises an outlet aperture 42 for the liquid.

[0060] Figures 2a-b schematically show side views of examples where the drainage arrangement 1 is configured to be arranged such that the outlet aperture 42 is essentially aligned with the circumferentially outer side 510 of the front frame 500 of the air filter assembly 100. More specifically, the outlet aperture 42 is essentially aligned with the circumferentially outer side 510 of the bottom beam 501 of the front frame 500. This way, a water column is created. The height H of the water column extends from the water level inside the first passage 30 to the outlet aperture 42 of the second passage 40. Figures 2a-c also show that the drainage arrangement 1 is arranged such that the second passage 40 is upstream of the front frame 500 in the airflow direction. Furthermore, the second passage 40 is formed between the outlet section 14 of the shield element 10 and the front frame 500. The shield element 10 is thus arranged with the outlet section 14 extending downwards along and possibly beyond the front side 530 of a bottom beam 501 of the front frame 500.

[0061] Figure 2c shows a cross-sectional view and a front view of an example of the drainage arrangement 1. The deflector section 12, and thus the first passage 30, has a first width W1 and the outlet section 14, and thus the second passage 40, has a second width W2. In this example, the first width W1 of the deflector section 12 essentially corresponds to the width of the at least one airflow inlet 200 of the air filter assembly 100.

[0062] Also, in this example the second passage 40 is tapering in direction away from the first passage 30 and towards the outlet aperture 42. The outlet section 14, and thus the second passage 40, has a tapering second width W2. The second width W2 at the outlet aperture 42 is smaller than the first width W1 of the first passage 30.

[0063] Figure 2c also shows the drainage arrangement 1 comprising two attachment sections 54 configured for snap-fit connection with the air filter assembly 100. In this example, the attachment sections 54 are configured to be connected to a respective front plate 430 of the air filter assembly 100. The attachment sections 54 may be integrated in the deflector section 12 of the shield element 10. Each attachment section 54 typically comprises a snap-fit element configured to engage with an edge of the front plate 430. This way, the shield element 10 will be held in place during use.

[0064] Figures 3a-c show a drainage arrangement 1 for an air filter assembly 100 according to examples of the present disclosure. The drainage arrangement 1 is in this example integrated in an air filter assembly 100. The air filter assembly 100 may be configured as in Figure 1. Specifically, the drainage arrangement 1 is integrated in the bottom beam 501 of the front frame 500 of the air filter assembly 100. The drainage arrangement 1 comprises a shield element 10 comprising a deflector section 12 configured to deflect an airflow passing through the at least one airflow inlet 200 of the air filter assembly 100. The deflector section 12 extends over the bottom plate 600 of the air filter assembly 100 and thereby forms a first passage 30 for the liquid. In the first passage 30, the accumulated liquid can flow in a direction essentially opposite to the direction of the airflow. The shield element 10 further comprises an outlet section 14 forming a second passage 40. In the second passage 40, the flow direction of the liquid is essentially perpendicular to the airflow direction. The second passage 40 comprises an outlet aperture 42 for the liquid.

[0065] In these examples, the second passage 40 constitutes a channel 44 in the bottom beam 501 of the front frame 500 and the outlet aperture 42 is formed at the circumferentially outer side 510 of the front frame 500. Thus, the outlet section 14 of the shield element 10 is integrated in the front frame 500. The outlet section 14 may form an inner part of the bottom beam 501 of the front frame 500 as shown in Figure 3a, or the outlet section 14 may form part of the front side 530 of the front frame 500 as shown in Figure 3b and 3c. The second passage 40 is formed by the outlet section 14 and an inner wall section 550 of the bottom beam 501 of the front frame 500. The inner wall section 550 of the front frame may be connected to the bottom plate 600 of the air filter assembly 100. In the example shown in Figure 3a, the outlet section 14 is essentially straight, whereas in Figure 3b and 3c the outlet section 14 is curved with the concave side facing the second passage 40. Furthermore, in the example shown in Figure 3c, the first passage 40 is tapering towards the second passage 40, and the second passage 40 is diverging towards the outlet aperture 42.

[0066] In the examples shown in figure 3b and 3c, the outlet section 14 comprises a resilient material, such as rubber, and also acts as a valve element 46. Thus, in these examples, the drainage arrangement 1 comprises an integrated valve element 46. In the figures, the valve element 46 is in an open state and thus allow liquid to flow through the second passage 40 and out through the outlet aperture 42. In order to close the second passage 40 and the outlet aperture 42, the valve element 46 is pushed in direction towards the inner wall section 550 of the front frame 500 so that the shape of the valve element 46 and thus the outlet section 14 is inverted. The inner side of the outlet section 14 will thereby abut the inner wall section 550 of the front frame 500 and no liquid will be able to pass through the second passage 40 or the outlet aperture 42.

[0067] Figures 4a-b schematically shows a drainage arrangement 1 according to an example of the present disclosure. The drainage arrangement 1 is in this example integrated in an air filter assembly 100. The air filter assembly 100 may be configured as in Figure 1. Specifically, the drainage arrangement 1 is integrated in the front frame 500 of the air filter assembly 100. The drainage arrangement 1 extends between two front plates 430 of the front frame 500. The drainage arrangement 1 comprises a shield element 10 comprising a deflector section 12 configured to deflect an airflow passing through the at least one airflow inlet 200 of the air filter assembly 100. The deflector section 12 extends over the bottom plate 600 of the air filter assembly 100 and thereby forms a first passage 30 for the liquid. In the first passage 30, the accumulated liquid can flow in a direction essentially opposite to the direction of the incoming airflow. The shield element 10 further comprises an outlet section 14 forming a second passage 40 together with a recess 45 in the front frame 500. In the second passage 40, the flow direction of the liquid is essentially perpendicular to the airflow direction. The second passage 40 comprises at least one outlet aperture 42.

[0068] The bottom beam 501 of the front frame 500 comprises a recess 45 allowing the liquid to flow vertically from the first passage 30 down to a level below the bottom plate 600. The recess 45 is formed at the front of the bottom beam 501 and the at least one outlet aperture 42 is arranged so that the liquid eventually flows out from the recess 45 and down over the front side 530 of the front frame 500. The liquid will thus flow through the outlet aperture 42 in a direction opposite to the incoming airflow. The recess 45 is delimited at a rear end by an inner wall section 550 of the front frame, which inner wall section 550 is connected to the bottom plate 600. The inner wall section 550 may comprise an essentially vertical portion and an essentially horizontal portion, wherein the horizontal portion is aligned with the bottom plate 600 and forms an extension of the bottom plate 600. The outlet section 14 extends from the deflector section 12 down to the bottom of the recess 45, aligned with the front side 530 of the bottom beam 501. The second passage 40 is thus formed by the inner wall section 550 of the bottom beam 501 of the front frame 500 and the outlet section 14. The outlet section 14 is configured to extend at least beyond the point where the liquid leaves the bottom plate 600 and starts flowing downwards in the second passage 40. This way, the liquid is protected from the incoming airflow and can be drained in an efficient way. The outlet section 14 may have a larger width closer to the deflector section 12 and a smaller width closer to the bottom of the recess 45. At the bottom of the recess 45, the outlet section 14 has a smaller width than the width of the recess 45. The outlet section 14 is arranged centrally in the recess 45 and thereby creates two outlet apertures 42, one on each side of the outlet section 14.

[0069] By having a shield element 10 that protects the liquid when it flows from the first passage 30 into the second passage 40 efficient drainage is achieved. Furthermore, by having the outlet apertures 42 formed in the front side 530 of the front frame 500 instead of at the circumferentially outer side 510 of the front frame, no valve element is required.

[0070] Figures 4c-d schematically show a drainage arrangement 1 according to an example of the present disclosure. Figure 4c shows a front view of the drainage arrangement 1, and Figure 4d shows a cross-sectional view. The drainage arrangement 1 is in this example integrated in an air filter assembly 100. The air filter assembly 100 may be configured as in Figure 1 or 4a-b. Specifically, the drainage arrangement 1 is integrated in the front frame 500 of the air filter assembly 100. The drainage arrangement 1 is arranged between two front plates 430 of the front frame 500. The drainage arrangement 1 comprises a shield element 10 comprising a deflector section 12 configured to deflect an airflow passing through the at least one airflow inlet 200 of the air filter assembly 100. As shown in Figure 4d, the deflector section 12 extends over a part of the bottom plate 600 of the air filter assembly 100 and thereby forms a first passage 30 for the liquid. In the first passage 30, the accumulated liquid can flow in a direction essentially opposite to the direction of the incoming airflow. The shield element 10 further comprises an outlet section 14 forming a second passage 40 together with a recess 45 in the front frame 500. In the second passage 40, the flow direction of the liquid is essentially perpendicular to the airflow direction and perpendicular to the flow direction in the first passage. The second passage 40 comprises two outlet apertures 42. The outlet section 14 is arranged centrally in the recess 45 and thereby creates two outlet apertures 42, one on each side of the outlet section 14.

[0071] The bottom beam 501 of the front frame 500 comprises a recess 45 allowing the liquid to flow vertically from the first passage 30 down to a level below the bottom plate 600. The recess 45 is formed at the front of the bottom beam 501 and the outlet apertures 42 are arranged so that the liquid eventually flows out from the recess 45 and down over the front side 530 of the front frame 500. The liquid will thus flow through the outlet apertures 42 in a direction opposite to the incoming airflow. The recess 45 may be delimited at a rear end by a wall section of the bottom plate 600. The outlet section 14 extends from the deflector section 12 down to the bottom of the recess 45, aligned with the front side 530 of the bottom beam 501. The second passage 40 is thus formed by the wall section of the bottom plate 600, the front frame 500 and the outlet section 14. The outlet section 14 is configured to extend at least beyond the point where the liquid leaves the bottom plate 600 and starts flowing downwards in the second passage 40. This way, the liquid is protected from the incoming airflow and can be drained in an efficient way. The outlet section 14 may have a larger width closer to the deflector section 12 and a smaller width closer to the bottom of the recess 45. At the bottom of the recess 45, the outlet section 14 has a smaller width than the width of the recess 45.

[0072] The drainage arrangement 1 further comprises a plurality of guiding elements 16 arranged in association with the shield element 10. A plurality of guiding elements 16 is arranged in the recess 45 on both sides of the shield element 10. The guiding elements 16 are configured to guide the incoming airflow laterally to the sides of the at least one airflow inlet 200. The main body of liquid typically flows centrally on the bottom plate 600 and will therefore not be affected by the laterally guided airflow. The airflow guided by the guiding elements 16 will help drag the liquid in the recess 45 laterally away from where it is shielded by the outlet section 14, and thus towards the two outlet apertures 42 where it falls out over the front side 530 of the front frame 500. Draining is thereby improved. The guiding elements 16 are curved and arranged so that channels are formed between two adjacent guiding elements 16. The guiding elements 16 may be integrated in the front frame 500 or in the bottom plate 600. The height of the guiding elements 16 may be at least 10 millimetres.

[0073] Figures 5a-b schematically show details of an air filter assembly 100 according to examples of the present disclosure. The air filter assembly 100 may be configured as disclosed in Figure 1. In this example, the bottom plate 600 of the air filter assembly 100 is sloping downwards towards the second passage 40 of the drainage arrangement 1 as shown in Figure 5a. The bottom plate 600 may additionally or alternatively be through-shaped as shown in Figure 5b.

[0074] Figure 6 schematically shows a drainage arrangement 1 according to an example of the present disclosure. In this example, the drainage arrangement 1 is arranged in an air filter assembly 100 as disclosed in Figure 1. The figure shows a first air filter assembly 100 arranged on top of a second air filter assembly 100. At least the second air filter assembly 100 is a symmetric air filter assembly, an example is illustrated in Figure 7, and thus comprises drainage arrangements 1 both at the top and the bottom of the air filter assembly 100. Specifically, the air filter assembly 100 comprises drainage arrangements 1 both at the top beam 501 and the bottom beam 501 of the front frame 500. The drainage arrangement 1 may be configured as in Figure 2a-c or 3a-c but in this example, the second passage 40 is laterally inclined in relation to a vertical axis. This way, the liquid drained from a drainage arrangement 1 in the first air filter assembly 100 will not flow straight down into the second passage 40 of the second air filter assembly 100. The figure also shows that the second passages 40 of the drainage arrangements 1 this way are offset in relation to each other.

[0075] Figure 7 shows a drainage arrangement 1 according to an example of the present disclosure. The air filter assembly 100 is configured as disclosed in Figure 1 but with integrated drainage arrangements 1. The air filter assembly 100 thus comprises three airflow inlets 200, each formed between a top beam 501, a bottom beam 501, and two front plates 430 of the front frame 500. The air filter assembly 100 is symmetric and could thus be rotated 180 degrees, and therefore comprises two drainage arrangements 1 per airflow inlet 200. One drainage arrangement 1 is arranged at each top beam 501 and bottom beam 501 sections of the airflow inlets 200. Thus, when rotated 180 degrees, the previous top beam 501 of the front frame 500 will be the bottom beam 501 of the front frame 500 and the side plate 420 previously at the top of the air filter assembly 100 would be at the bottom of the air filter assembly 100 and thereby constitute the bottom plate 600.

[0076] The person skilled in the art realizes that the present disclosure is not limited to the preferred embodiments described above. The person skilled in the art further realizes that modifications and variations are possible within the scope of the appended claims. Additionally, variations to the disclosed embodiments can be understood and effected by the skilled person in practicing the claimed disclosure, from a study of the drawings, the disclosure, and the appended claims.

Claims

CLAIMS1. A drainage arrangement (1) for an air filter assembly (100), the drainage arrangement (1) being configured to be arranged at an airflow inlet (200) of the air filter assembly (100) to allow liquid that has accumulated inside the air filter assembly (100) to exit the air filter assembly (100), the drainage arrangement (1) comprising:- a shield element (10) comprising a deflector section (12) configured to deflect an airflow passing through the airflow inlet (2); wherein the shield element (10) is configured to be arranged so that a first passage (30) for the liquid is formed between the deflector section (12) and a bottom plate (600) of the air filter assembly (100), the first passage (30) allowing the accumulated liquid to flow in a direction essentially opposite to the direction of the airflow; and wherein the shield element (10) further comprises an outlet section (14) forming a second passage (40), in which second passage (40) the flow direction of the liquid is essentially perpendicular to the airflow direction, wherein the second passage (40) comprises an outlet aperture (42) for the liquid, the outlet section (14) being connected to the deflector section (12).

2. The drainage arrangement (1) according to claim 1, wherein the drainage arrangement (1) is configured to be arranged such that the outlet aperture (42) is aligned with, or below, a circumferentially outer side (510) of a front frame (500) of the air filter assembly (100), the front frame (500) forming the airflow inlet (200).

3. The drainage arrangement (1) according to claim 1 or 2, wherein the second passage (40) is laterally inclined in relation to a vertical axis when the drainage arrangement (1) is mounted.

4. The drainage arrangement (1) according to any one of the preceding claims, wherein the second passage (40) is tapering in direction away from the first passage (30) and towards the outlet aperture (42).

5. The drainage arrangement (1) according to any one of the preceding claims, wherein the drainage arrangement (1) comprises at least one attachment section (54) configured for snap-fit connection with the air filter assembly (100).

6. An air filter assembly (100) comprising:- a frame structure (400) including a front frame (500) and a bottom plate (600), and- at least one filter media element (700) arranged within the frame structure (400), the front frame (500) forming at least one airflow inlet (200) into the air filter assembly (100), wherein the air filter assembly (100) comprises a drainage arrangement (1) according to any one of claims 1-4, arranged at the airflow inlet (200) to allow liquid that has accumulated inside the air filter assembly (100) to exit the air filter assembly (100).

7. The air filter assembly (100) according to claim 6, wherein the drainage arrangement (1) is detachably connected to the front frame (500).

8. The air filter assembly (100) according to claim 7, wherein the drainage arrangement (1) is arranged such that the second passage (40) is upstream of the front frame (500) in the airflow direction.

9. The air filter assembly (100) according to claim 7 or 8, wherein the second passage (40) is formed between the outlet section (14) of the shield element (10) and the front frame (500).

10. The air filter assembly (100) according to claim 6, wherein the drainage arrangement (1) is integrated in the air filter assembly (100).

11. The air filter assembly (100) according to claim 10, wherein the second passage (40) comprises a channel (44) in the front frame (500) and the outlet aperture (42) is formed at a circumferentially outer side (510) of the front frame (500).

12. The air filter assembly (100) according to claim 10 or 11, wherein the drainage arrangement (1) further comprises an integrated valve element (46) arranged to block the outlet aperture (42) when drainage is not required.

13. The air filter assembly (100) according to claim 10, wherein the second passage (40) is formed by the outlet section (14) and a recess (45) in the front frame (500), allowing the liquid to flow through the second passage (40) down to a level below the bottom plate (60).

14. The air filter assembly (100) according to any one of claims 6-13, wherein the air filter assembly (100) is a V-type filter assembly.

15. The air filter assembly (100) according to any one of claims 6-14, wherein the bottom plate (600) is sloping towards the second passage (40) and / or is through-shaped.

Images