Patent ID: 12186692

The Figures are not drawn to scale. Generally, identical components are denoted by the same reference numerals in the Figures.

DETAILED DESCRIPTION OF EMBODIMENTS

The present disclosure will be described in terms of specific embodiments, which are illustrative of the disclosure and not to be construed as limiting. It will be appreciated by persons skilled in the art that the present disclosure is not limited by what has been particularly shown and/or described and that alternatives or modified embodiments could be developed in the light of the overall teaching of this disclosure. The drawings described are only schematic and are non-limiting.

Use of the verb “to comprise”, as well as the respective conjugations, does not exclude the presence of elements other than those stated. Use of the article “a”, “an” or “the” preceding an element does not exclude the presence of a plurality of such elements.

Furthermore, the terms first, second and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequence, either temporally, spatially, in ranking or in any other manner. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the disclosure described herein are capable of operation in other sequences than described or illustrated herein.

Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiments is included in one or more embodiment of the present disclosure. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to one ordinary skill in the art from this disclosure, in one or more embodiments.

When the wording “collar” or “collar-shaped portion” is used throughout this specification, it can be construed as an element or part of an element configured for enclosing/contouring an element or object or for enclosing/contouring a circumferential wall of an element or object. The collar or collar-shaped portion is not limited to symmetric regular shapes such as shapes of a ring, a cylinder or an obround, but other irregular shapes for forming a contour around elements/objects or around circumferential walls having an irregular radial boundary are conceived as well. Hence, the collar or collar-shaped portion can also have an irregular shape. For example, if a wall having an indentation portion is to be contoured by the collar or by the collar-shaped portion, the collar can have a corresponding irregular shape, for example having a protruding portion, in order to fit with the indentation portion of the wall. Additionally, the shape of the collar or the collar-shaped portion can vary, for example variations can occur between a stretched or a non-stretched state of the collar or collar-shaped portion.

When the wording “coupled” or “sealingly coupled” is used for expressing for example a coupling between two surfaces or two elements, it can be construed as either a direct coupling or an indirect coupling. A direct coupling is a direct connection between for example the two surfaces to be coupled by pressing the two surface together with or without an adhesive in between, such as a glue. On the other hand, an indirect coupling involves the use of for example further additional intermediate elements for establishing the coupling between the two surfaces. The additional intermediate element can for example include additional surfaces that are pressed and/or glued together, or sealingly fixed together in any other way.

The wording “encircling” used herein is to be construed as encompassing, surrounding or forming a circle around something. For example, a sealing surface that is encircling the outer sidewall of a housing when in sealed position implies by definition that the sealing surface is encompassing an outer surface of the outer sidewall of the housing.

As discussed above, the filter element according to the present disclosure is a component for mounting in a housing of a filter system and comprises a filter medium pack wherein a filter medium catches particles and impurities that are present in an incoming fluid flow. Although a number of the drawings presented and discussed below are specifically addressing embodiments of a filter element for filtering air, the present disclosure is not limited to any specific fluid. The fluid is for example a gas such as air.

Filter Medium Packs, Generally

A filter medium pack for use in a filter element according to the present disclosure is first discussed. Referring toFIG.1a,FIG.1bandFIG.1c, a cross-section of respectively a first, a second and a third embodiment of a filter medium pack10is schematically shown. The filter medium pack10is extending along a longitudinal axis Z from a first end z1to a second end z2and comprises an axial inlet side7at the first end z1of the filter medium pack for receiving the unfiltered fluid, for example a gas such as air. A circumferential side6forms a radial boundary of the filter medium pack10. Fluid entering the axial inlet side7, crosses the filter medium5and finally exits the filter medium pack is schematically illustrated with black arrows onFIGS.1ato1c.

Filter elements according to the present disclosure may use different kinds of filter medium packs, including filter medium packs comprising pleated filter media and filter medium packs comprising fluted filter media. A variety of these filter medium packs are commercially available and are known to the skilled person.

The flow direction of the fluid crossing the filter medium pack10can vary depending on the specific type of filter medium pack used. For example, for the first and third embodiment of the filter medium pack10shown onFIG.1aandFIG.1c, respectively, the fluid is crossing the filter medium5in a direction essentially parallel with the longitudinal axis Z and the filtered fluid is exiting the filter medium pack at an axial outlet side8at the second end z2of the filter medium pack. On the other hand, in the second embodiment of a filter medium pack10as shown onFIG.1b, the fluid is crossing the filter medium in a direction transverse to the longitudinal axis Z. In this second embodiment, the filter medium5has the shape of for example a hollow cylinder with a central axis coinciding with the longitudinal axis Z. In this example shown onFIG.1b, the axial inlet side7of the filter medium pack comprises a ring-shaped flange13having an axial opening for supplying the unfiltered fluid to the filter medium5and the axial side8of the filter medium pack at the second end z2is covered with a closed flange14. In the second embodiment shown inFIG.1b, the filter medium can for example be a pleated medium. For each of the examples shown atFIGS.1A-1C, flow can also be the reverse of that shown.

In embodiments wherein the filter medium pack10comprises a fluted filter medium5, the fluted filter medium5comprises for example coiled layers of fluted filter material. Those layers are axially coiled with respect to the longitudinal axis Z. In these embodiments, an outer surface of an outer layer of the coiled fluted filter medium is forming the circumferential side6of the filter medium pack10. Such a coiled fluted filter medium is for example disclosed in U.S. Pat. No. 5,820,646. In other embodiments, as illustrated onFIG.1c, to improve the necessary dimensional stability, the filter medium pack10comprises a supporting shell9, for example made of a rigid plastic, surrounding the filter medium5or surrounding part of the filter medium5. In these embodiments, an outer surface of the supporting shell9is forming the circumferential side6of the filter medium pack10.

The present disclosure is not limited to any specific shape of the filter medium pack. For example, the cross section between the circumferential side6of the filter medium pack10and a plane perpendicular to the longitudinal axis Z, for instance can have a shape of a circle, an oval, obround, an ellipse or a rounded square.

The filter medium packs10are generally dimensioned in accordance with the housing they have to fit with. The filter medium pack/filter element can be inserted in the housing through a service opening of the housing. The insertion of exemplary filter elements100into a housing50so as to enclose or partly enclose the circumferential side6of the filter medium pack10with an outer sidewall51of the housing50is schematically illustrated onFIGS.4ato4f,FIGS.5ato5eandFIGS.6ato6e.

Filter Element with Bridge Seal Arrangement, General Characterization

In general terms, the filter element100according to the disclosure comprises a filter medium pack10as discussed above and a bridge seal arrangement20for bridging a gap between the radial boundary of the filter medium pack and the outer sidewall of the housing.

When for example an air filter element is being used and inserted in a housing50, the bridge seal arrangement20provides for a separation between the filtered air and the ambient air surrounding the housing50. Hence, the filtered air does not get polluted with ambient unfiltered air.

Various embodiments of a bridge seal arrangement20according to an aspect of the disclosure exist and a number of examples are schematically shown onFIGS.2ato2fandFIGS.3ato3e. Such a bridge seal arrangement20of the filter element100is characterized in that it has a first collar-shaped portion20acomprising a first circumferential sealing surface41sealingly coupled to the circumferential side6of the filter medium pack10or sealingly coupled to a border of the axial inlet side7. The bridge seal arrangement20has a second collar-shaped portion20bthat is coupled with the first collar-shaped portion20a, and the second collar-shaped portion20bcomprises a second circumferential sealing surface42configured for encircling and sealingly cooperating with the outer sidewall51of the housing.

In embodiments, illustrated onFIG.2atoFIG.2f, the first collar-shaped portion20aand the second collar-shaped portion20bform a coupled body that can, for example, be made out of a single material, as illustrated on the these Figures with a black colour. This coupled body can for example be made out of an elastomer, such as synthetic rubber or natural rubber.

In other embodiments, the bridge seal arrangement20is composed out of various materials by combining parts made of, for example, an elastomer and other parts made of, for example, a rigid plastic or another rigid material. Examples of embodiments of bridge seal arrangements20being composed of multiple parts made of various materials are illustrated onFIGS.3ato3ewhere the parts coloured in black are made out, of for example, an elastomer and the hatched parts are, for example, made out of a hard plastic or any other relatively more rigid material.

In embodiments, as illustrated for example onFIG.6bandFIG.6e, the bridge seal arrangement20comprises a collar-shaped bridging portion20ccoupling the second collar-shaped portion20bwith the first collar-shaped portion20a. This bridging portion20callows, when the air filter element100is inserted in a housing51, to define and maintain a spacing between the outer side6of the filter medium pack10and an outer wall of the housing. In this way, the filter medium pack10maintains a degree of movement within the housing allowing to absorb vibrations.

The bridge seal arrangement20is not limited to a particular number of collar-shaped portions that are coupled together, for example in alternative embodiments, besides the first collar-shaped portion20a, the second collar-shaped portion20band the collar-shaped bridging portion20c, the bride seal arrangement20comprises additional collar-shaped portions.

Coupling of the Bridge Seal Arrangement with the Filter Medium Pack

As mentioned above, the first collar-shaped portion20aof the bridge seal arrangement20forms a sealed coupling with the filter medium pack10, either with the circumferential side6of the filter medium pack10or either with a border of the axial inlet side7of the filter medium pack10. Both type of coupling arrangements will be discussed.

For coupling the first circumferential sealing surface of the first collar-shaped portion20ato the circumferential side6of the filter medium pack10a glue or any other adhesive means can be used, thereby providing a permanent and sealed connection. Alternatively, or in combination therewith, if the first collar-shaped portion20ais made of an elastic material, such as an elastomer, the inner diameter of the first collar-shaped portion20acan be configured such that the first collar-shaped portion20ais stretched when positioning around the circumferential side6of the filter medium pack. As a result, a radial opposing force is pressing the first circumferential sealing surface against the circumferential side6of the filter medium pack10. Additionally, or in the alternative, or in combination therewith, a fixation strap can be provided around the first collar-shaped portion20afor firmly pressing the first circumferential sealing surface against the circumferential side6of the filter medium pack10.

InFIG.4atoFIG.4dandFIG.5atoFIG.5c, examples are shown of bridge seal arrangements20wherein the first circumferential sealing surface of the first collar-shaped portion20ais sealingly coupled to the circumferential side6of the filter medium pack10. These are examples where the first and second collar-shaped portions of the bridge seal arrangement forma coupled body made from a single material, as discussed above.

Bridge seal arrangements20composed of different parts of different materials, and wherein the first collar-shaped portion is for example made of a rigid material, can also be coupled to the circumferential side6of the filter medium pack. The bridge seal arrangement20ofFIG.3dis shown in combination with a filter medium pack10inFIG.5dandFIG.6e, illustrating that the first circumferential sealing surface41is coupled to the circumferential side of the filter medium pack10. In these embodiments, the coupling can also be made with a glue or any other adhesive or fixation means. The bridge seal arrangement20shown onFIG.3dandFIG.6eis a particular bridge seal arrangement that reduces the fluid inflow stream.

The first collar-shaped portion20aof the bridge seal arrangement20according to the present disclosure can be coupled with the circumferential side6of any of the exemplary filter medium packs10discussed above and illustrated onFIG.1atoFIG.1c.

If a filter medium pack10as discussed above and shown onFIG.1aorFIG.1bis used, the coupling of the first collar-shaped portion20ato the circumferential side6of the filter medium pack can be made at any longitudinal position with respect to the longitudinal axis Z, i.e. at any longitudinal position between the first end z1and the second end z2. InFIG.4b, an example is shown where the coupling is made about half-way between the first and second end. In this way, the housing is advantageously being reduced in size.

An example of a first collar-shaped portion20acoupled to the filter medium pack10of the type shown onFIG.1b, is illustrated onFIG.4f. In this example, the first circumferential sealing surface41of the first-collar shaped portion20ais sealingly coupled to a radial side of the ring-shaped flange13at the inlet side7. This coupling can also be made with a glue or any other fixation means.

As mentioned above, in embodiments of a filter element100according to the present disclosure, the first circumferential sealing surface41of the first-collar shaped portion20acan also be coupled to a border of the axial inlet side7. A border of the axial inlet side should be construed in the broadest possible sense. The border is, for example, a peripheral radial edge area of the axial inlet side7or in another example the border is a circumferential surface portion of the axial inlet side7. Two examples of coupling the first collar-shaped portion to a border of the axial inlet side7are further discussed.

InFIG.5e, a filter element100is shown comprising the bridge seal arrangement ofFIG.3e. In this embodiment, the first-collar shaped portion20ais part of the hatched circumferential element40shown onFIG.3e. This circumferential element40is for example made of a rigid material and the first circumferential sealing surface41of the first-collar shaped portion20acan be glued to the border of the inlet side7. When using such a bridge seal arrangement in combination with a filter medium pack10shown onFIG.1aorFIG.1c, the consequence, as can be observed fromFIG.5e, is that the inlet flow surface is reduced.

InFIG.4eandFIG.6d, a further example is shown of a filter element wherein the first-collar shaped portion20ais coupled to a border of the inlet side7. In this example, the bridge seal arrangement20is made of a single material, e.g. an elastomer. In this embodiment, the first circumferential sealing surface41of the first-collar shaped portion20ais coupled, for example with a glue, to a circumferential surface portion of the axial inlet side7forming the border of the axial inlet side7.

Bridge Seal Arrangements, Sealed and Un-Sealed Positions

In embodiments according to the present disclosure, the bridge seal arrangement20can be configured for moving the second collar-shaped portion20bwith respect to the first collar-shaped portion20afrom a first position to a second position and vice-versa. As mentioned above, the first and second positions are also named un-sealed position and sealed position, respectively. For example, to insert or remove the filter element from the housing, the second collar-shaped portion20bis to be moved between a sealed and un-sealed position.

In some embodiments, when moving the second collar-shaped portion20bfrom an un-sealed to a sealed position, the second-collar shaped portion20bis substantially stretched while in other embodiments the second collar-shaped portion20bis not substantially stretched but for example only bent/flexed or folded when in the sealed position. Whether the second-collar shaped portion20bis substantially stretched or not will depend on the detailed design of the bridge seal arrangement and on the material the second-collar shaped portion is made of.

Preferably, the bridge seal arrangement20is configured such that, when moving from the un-sealed to the sealed position, the second collar-shaped portion is stretched and/or flexed such that the second collar-shaped portion is elastically deformed when in the sealed position. In other words, in order to position the second collar-shaped portion20baround the outer sidewall51of the housing50such that the second circumferential sealing surface42is encircling and sealingly cooperating with the outside surfaces51oof the outer sidewall51, the second collar-shaped portion is to be stretched and/or flexed in order to firmly fit around the outer sidewall51.

Advantageously, for embodiments where the second collar-shaped portion is made of an elastomer, the second collar-shaped portion is, due to the stretching and/or flexing, predominantly elastically deformed when in the sealed position. In this way, as a result of the forces applied for stretching and deforming the seal, a radial opposing force is pressing automatically/intrinsically the second circumferential sealing surface against the outer sidewall of the housing. Advantageously, by using a stretchable seal, a secure sealing is obtained and there is no need for adding an additional fixation member, such as for example a fixation clamp around the second collar-shaped portion20b.

In other embodiments, to increase the radial force pressing the second circumferential sealing surface against the outer sidewall of the housing and/or to maintain the second collar-shaped portion in place, a fixation clamp24as shown onFIG.7bcan be optionally added.

Whether a fixation means such as a fixation clamp or a fixation ring is mandatory or not also depends on the type of fluid used and the specific application the filter element is used for. Depending on the application, e.g. use of a liquid such as oil or use of a gas such as air, the pressure differences between the filtered fluid and the unfiltered fluid can be quite different. For applications where the fluid is for example an oil, e.g. for hydraulic applications, and where pressure differences can be high, an additional fixation means is preferably provided.

A number of embodiments of bridge seal arrangements are now discussed in more detail. A distinction can be made between embodiments where the second collar-shaped portion is elastic and is substantially stretched for forming a sealed coupling and embodiments were the second collar-shaped portion is, although potentially elastic, not substantially stretched, i.e. made longer or wider, but only for example bent/flexed when in the sealed position. A third category of embodiments are embodiments wherein the collar-shaped portion is non-stretchable and where fixation means are required for keeping the second collar-shaped portion in the sealed position.

a) Substantially Stretchable Seal Arrangements

Examples of bridge seal arrangements20that are substantially stretched when moving from an un-sealed to a sealed position are, for example, shown onFIG.2fandFIGS.3ato3e. InFIG.5btoFIG.5d, examples of filter elements are shown wherein these type of bridge seal arrangements20are in an un-sealed position, and inFIG.6bandFIG.6cexamples are shown of a sealed position.

A preferred embodiment of a bridge seal arrangement20according to the present disclosure is shown onFIG.2eand is further named wide band seal. This embodiment can indeed be considered as a wide elastic and stretchable band wherein a lower portion and an upper portion forms respectively the first20aand second20bcollar-shaped portion of the bridge seal arrangement20. In other words, the first and second collar-shaped portion form a coupled single body that is preferably made of a stretchable single material such as an elastomer. The wide band seal does not necessarily need to have a cylindrical shape but the wide band seal can have any suitable shape adapted accordingly to the shape of the filter medium pack and/or the shape of the housing the band has to fit with. The opening through the first20aand second20bcollar-shaped portion are also not necessarily the same. For example, the wide band seal can have the shape of a truncated cone wherein a lower base part of the cone corresponds to the first collar-shaped portion20aconfigured to fit with the filter medium pack and a truncated upper part of the cone corresponds to the second collar-shaped portion20bconfigured to firmly fit around the outer sidewall of the housing after folding/stretching/flexing the second collar-shaped portion.

As illustrated onFIG.6bandFIG.13, to form a sealed connection between the outer wall51of the housing and the second collar-shaped portion20bof the wide band seal, the wide band seal is folded and stretched. In some embodiments, in order to facilitate this folding and stretching of the band, one or more folding lines20gare provided, as shown onFIG.2fIndeed, as schematically illustrated on for exampleFIG.2fandFIG.3d, the second collar-shaped portion20bcomprises a first section and a second section wherein a wall thickness of the first section is smaller than a wall thickness of the second section. In this way the one or more predetermined folding lines20gare formed in the second-collar shaped portion. Indeed, the sections where the wall thickness is reduced are predetermined in order to facilitate a folding and/or stretching of the bridge seal arrangement20to the right locations. In further embodiments, as illustrated for example inFIG.11aandFIG.11b, to further improve the folding of the bridge seal arrangement20, the collar-shaped bridging portion20ccomprises a third section and a fourth section wherein a wall thickness of the third section is smaller than a wall thickness of the fourth section. The different wall thicknesses are configured not only to facilitate the folding of the bridge seal arrangement20but also to avoid that the foldable seal is folding back from the sealed to the un-sealed position.

Predetermined folding lines can be made in the second collar-shaped portion20band/or bridging portion20c, as mentioned above, by reducing the wall thickness at specific predetermined locations. Alternatively, starting from a given overall wall thickness, the wall thickness can also be reinforced at predetermined locations in order to generate thickness variations and hence obtain the same effect of facilitating the folding of the bridge seal arrangement.

In the embodiments shown onFIG.2fandFIG.3d, the predetermined folding lines20gare illustrated as radial lines in the elastic band45. However, in alternative embodiments, predetermined folding lines can also be made in a longitudinal direction parallel with a central axis of the bridge seal arrangement. For example if the housing has a rounded square shape, longitudinal predetermined folding lines can be provided in the second collar-shaped portion20bby, for example, reducing the wall thickness of the collar-shaped portion at those specific locations corresponding with the corner portions of the housing. In this way, the second collar-shaped portion will also firmly fit in the corners of the housing.

Reference is made toFIG.11aandFIG.11bwhere an example of a wide band seal is shown in more detail when in the un-sealed position and in the sealed position, respectively. In this example, the bridge seal arrangement20comprises a lip portion20dcoupled to the first collar-shaped portion20aand configured for cooperating with an inner surface51iof the outer wall51of the housing to additionally maintain/position the bridge seal arrangement20in position when folded in the sealed position.

Advantageously, the wide band seal embodiment can be used in combination with any of the filter medium packs10discussed above and shown onFIG.1atoFIG.1c.FIG.10aandFIG.10billustrate for example a filter element100wherein a wide band seal is coupled to a filter medium pack10corresponding to respectivelyFIG.1aandFIG.1c.

In embodiments, the second circumferential sealing surface42forms a radially outward-facing circumferential surface and a radially inward-facing circumferential surface when the second collar-shaped portion20bis in respectively the un-sealed and the sealed position. InFIG.2f, an example is shown of an un-sealed position, illustrating that the second circumferential sealing surface42of the second collar-shaped portion20bis facing radially outwardly, i.e. the second circumferential sealing surface42is located at the outside of the second collar-shaped portion20bwhen in the un-sealed position. On the other hand, inFIG.6b, an example of a sealed position is shown, illustrating that the second circumferential sealing surface42of the second collar-shaped portion20bis facing radially inwardly, i.e. the second circumferential sealing surface42is located at the inside of the second collar-shaped portion20bwhen in the sealed position. In these embodiments, a circumference of the circumferential sealing surface42is increasing from a first value Coutto a second value Cinwhen moving from the un-sealed to the sealed position, with

Ci⁢n-CoutCo⁢u⁢t≥1⁢%,
preferably

Ci⁢n-CoutCo⁢u⁢t≥5⁢%,
more preferably

Ci⁢n-CoutCo⁢u⁢t≥10⁢%.

Alternative embodiments of bridge seal arrangements20comprising an elastic and stretchable band45are shown onFIGS.3a,3dand3e. In these embodiments the band45, made out of for example an elastomer, is coupled to a further circumferential element40that is made out of a rigid material such as a hard plastic or a metal. In these embodiments, as illustrated onFIG.3a,FIG.3dandFIG.3e, the first collar-shaped portion20aof the bridge seal arrangement20corresponds to a portion of the circumferential element40and the second collar-shaped portion20bcorresponds to an upper portion of the elastic band45. These type of bridge seal arrangements20are further illustrated onFIG.5d,FIG.5eandFIG.6e, where the bridge seal arrangements are shown in combination with a filter medium pack10and a housing50.

A further example of a substantially stretchable bridge seal arrangement20is shown onFIG.3candFIG.8awherein a flexible and stretchable band, preferably made out of an elastomer and coloured in black onFIG.3c, is coupled to a circumferential element that is made out of a rigid material such as a hard plastic or a metal, and wherein this circumferential element is forming the first collar-shaped portion20aof the bridge seal arrangement20.

b) Substantially Flexible/Bendable Seal Arrangement

Filter elements comprising bridge seal arrangements20as for example shown onFIG.2atoFIG.2d,FIG.4atoFIG.4dandFIG.6aandFIG.6c, are examples where there is no major stretching necessary to bring the second collar-shaped portion20bin the sealed position. These type of bridge seal arrangements can be brought in the sealed position by, for example, slightly bending/flexing the second collar-shaped portion outwardly when inserting the filter element in the housing. When this second collar-shaped portion20bis made of an elastomer, the bending/flexing also results in an elastic deformation. As discussed above, an opposing radial force will press the second circumferential sealing surface against the outer sidewall of the housing. However, when compared to the wide band seal discussed above the opposing radial force can be weaker. Hence, in these embodiments, a fixation clamp can optionally be added around the second collar-shaped portion to increase the radial force and/or keep the bridge seal arrangement in place.

c) Bridge Seal Arrangements Using a Fixation Clamp

For embodiments where the second collar-shaped portion20bis not being stretched when positioning the second collar-shaped portion20baround the outer sidewall51of the housing50, but for example only bent or folded without elastic deformation, a fixation clamp24or any other fixation means is needed to press and maintain the second circumferential surface42against the outer sidewall51. For example, when using a bridge seal arrangement20as shown onFIG.3bwherein the second collar-shaped portion20bis mainly made of a rigid material, the second collar-shaped portion20bcan be folded or bent with respect to the first collar-shaped portion20adue to a bridging portion20ccoupling the first and second collar-shaped portions. In this example, the second collar-shaped portion20bcomprises a sealing member47that is for example made out of an elastomer and that comprises the second circumferential sealing surface42. To maintain this second circumferential sealing surface42pressed against the outer sidewall of the housing, a fixation means such as a clamp is used.

A further example of a bridge seal arrangement requiring a fixation clamp is shown onFIG.2e. In this embodiment, the second collar shaped portion20b, is made out of an elastic material such as an elastomer and needs to be moved/folded in the direction shown by the arrows in order to bring the second sealing surface42in contact with the outer wall of the housing. These type of embodiments require a fixation clamp to maintain the second sealing surface42pressed against the outer wall51of the housing and when releasing and removing the clamp, the second collar shaped portion20bwill automatically, due to the elastic properties of the second collar-shaped portion, move back to the unsealed position shown onFIG.2e.

Outer Sidewall of the Housing

When using a bridge seal arrangement20wherein at least the second collar-shaped portion20bis stretched and/or flexed and thereby elastically deformed when moving from the un-sealed to the sealed position, the second circumferential sealing surface42of the second collar-shaped portion20bcan sealingly cooperate with outer surface51oof the sidewall51of various shapes. Indeed, the outer sidewall surface51ocan for example have a drop shape or any other shape that can be contoured by the second circumferential sealing surface42of the second collar-shaped portion20b. Due to the opposing force resulting from the elastic deformation, the second circumferential sealing surface42will be firmly pressed against the outer sidewall surface51oindependently of the shape of the outer wall.

In embodiments according to the present disclosure, and as illustrated inFIG.5b, the second collar-shaped portion20bcomprises a sealing rib21wherein a radial surface of the radial sealing rib21forms the second circumferential sealing surface42. Advantageously, a groove51acan be provided in the outer sidewall51of the housing as illustrated onFIG.5band be configured such that when the bridge seal arrangement is in the sealed-position, the sealing rib21engages with the groove51afor forming a firm sealing, illustrated onFIG.6b. In particular embodiments, the outer sidewall51of the housing comprises as an alternative, or in addition to the groove51a, further anchoring means. For example, instead of a continuous radial groove, one or more discrete indentations can be made onto the outer sidewall51and the second circumferential sealing surface42is then adapted accordingly with for example corresponding discrete bulbous portions that sealingly fit with the indentations.

In an embodiment, illustrated onFIG.9a, the second collar-shaped portion20bcomprises an inwardly protruding portion20fconfigured for fitting and/or cooperating with an indentation portion51bof the outer sidewall51. As shown onFIG.9a, this indentation portion51bis for example a portion that is forming a convex surface portion at the inside surface51iof the outer sidewall51and forming a concave surface portion on the outside surface51oof the outer sidewall51. The convex portion can also be construed as an inwardly directed portion. In this way, a specific orientation can be defined for the filter element100with respect to the housing. In some embodiments as shown onFIG.9b, the second collar-shaped portion20bcomprises multiple inwardly protruding portions20fand the outer wall51comprises corresponding multiple indentation portions51b. In this example shown onFIG.9b, four indentation portions51band four corresponding inwardly protruding portions20fare schematically illustrated.

In embodiments, the second collar-shaped portion of the bridge seal arrangement can have a different radial stretchability along its perimeter.

In embodiments comprising a stretchable bridge seal arrangement20, as discussed above, the second collar-shaped portion20bcomprises an engaging section20hconfigured for engaging with a matching section of the outer sidewall51of the housing. In this way, the second collar-shaped portion20bof the bridge seal20is hold in place when being in the sealed position. A further advantage of such a bridge seal configuration is that when moving the second collar-shaped portion20bfrom the un-sealed to the sealed position, the positioning of the second collar-shaped portion around the outer sidewall51of the housing is facilitated. Examples of such embodiments are shown inFIG.19aandFIG.19bwherein the circles indicate the area where the engaging section20hof the seal20is engaging with a corresponding matching section of the outer sidewall51of the housing.

In the embodiment shown inFIG.19a, the matching section of the outer sidewall51is formed by a circumferential rim51cand the engaging section20hof the seal has a circumferential indentation configured such that when the seal20is in the sealed position, as shown inFIG.19a, the indentation20his engaging with the rim51cof the outer sidewall51of the housing, so as to hold the seal20in the sealed position.

In the embodiment shown inFIG.19b, the matching section of the outer sidewall51is formed by a circumferential groove51dand the engaging section20hof the seal has a circumferential lip20jconfigured such that when the seal20is in the sealed position, as shown inFIG.19b, the lip20jis engaging with the groove51dof the outer sidewall51of the housing, so as to hold the seal20in the sealed position. In the embodiment shown onFIG.19b, the seal20comprises a further lip20iconfigured for cooperating with a wall portion of for example a cover of the housing or a pre-cleaner75.

Installation Tools and Auxiliary Equipment

As already discussed above and as shown onFIG.7ba fixation clamp24can be positioned around the second collar-shaped portion20bof any of the bridge seal arrangements20according to the present disclosure. Such fixation clamp24is configured for pressing the second circumferential sealing surface42against the outer sidewall51of the housing. In this way, a secure sealing can be established and air leakage can be avoided, especially for situations where the air filter element100is exposed to heavy vibrations.

In some embodiments, installation tools are provided for switching a foldable bridge seal arrangement between an unsealed and a sealed position. For example,FIG.8apresents an embodiment wherein the bridge seal arrangement20comprises a rigid guiding element22attached to the second collar-shaped portion20b. This rigid guiding element22allows for facilitating the folding and unfolding of the bridge seal arrangement by performing a translation motion of the rigid element22, for example along an axis parallel with the longitudinal axis Z of the filter element as indicated by the black arrow onFIG.8a. In a further example, shown onFIG.8b, a removable installation tool23is provided between the first and second collar-shaped portions of the bridge seal arrangement20in order to increase a distance between the first and second collar-shaped portions and generate for example an elastic deformation to the second collar-shaped portion20b. In this embodiment, the bridge seal arrangement20is configured such that after removing the installation tool23by moving the installation tool in a direction that is for example parallel with the longitudinal axis as shown with the black arrow onFIG.8b, a radial opposing force is pressing the second circumferential sealing surface42against the outer sidewall51of the housing.

FIGS.10aand10bpresent a cross sectional view of an example of a filter element100comprising an air filter pack10and a foldable/stretchable bridge seal arrangement20positioned in an un-sealed position. In this example, the bridge seal arrangement20comprises one or more handles20ecoupled to the second collar-shaped portion20b. These handles allow to help to fold the bridge seal arrangement from the unsealed position to the sealed position. As will be discussed below, when in the sealed position, the handles can also be attached to protruding elements56of the housing as further illustrated onFIG.12andFIG.13.

FIG.7cillustrates part of an embodiment of an air filter element comprising a bridge seal arrangement20for use with a pre-cleaner75or a cover. The pre-cleaner75or cover is configured for pushing the second collar-shaped portion20bof the bridge seal arrangement20from an unsealed position to a sealed position. As illustrated by the black arrow onFIG.7c, by translating the pre-cleaner75or the cover along an axis parallel with the longitudinal axis of the air filter element, the second collar-shaped portion20bwill be folded with respect to the first collar-shaped portion until the second circumferential sealing surface42is making contact with the outer sidewall51of the housing.

Filtering Element Kit

The filtering elements100according to the present disclosure, as discussed above, have two major parts, namely the filter medium pack10and the bridge seal arrangement20.

The filter element100can either be construed as a single unit or as a kit of parts comprising at least a first part being the filter medium pack10and a second part being the bridge seal arrangement20.

For example, the filter element can be provided as a unit manufactured in a factory where the first circumferential sealing surface41of the first collar-shaped portion20ais sealingly coupled to the circumferential side6of the filter medium pack10or sealingly coupled to a border of the axial inlet side7in the factory as part of the manufacturing process of the filtering element100.

Alternatively, a filter element kit can be provided comprising a filter medium pack10and a bridge seal arrangement20, wherein the end-user can sealingly couple the first circumferential sealing surface41to the circumferential side6of the filter medium pack10, or to a border of the axial inlet side7, for example at the moment of installation of the filter element100in the housing50.

Filter Systems

The present disclosure also pertains to a filter system comprising a filter element100as discussed above. A perspective view and a cross-sectional view of an exemplary embodiment of a filter system200is illustrated in respectivelyFIG.12andFIG.14b. The filter system is for example an air filter system comprising an air filter element.

Such a filter system200according to the present disclosure comprises a housing50having an outer sidewall51enclosing or partly enclosing the circumferential side of the filter medium pack10of the filter element100. As shown onFIG.15b, the second circumferential sealing surface of the second collar-shaped portion20bis encircling and sealingly cooperating with the outer sidewall51of the housing.

The housing50of the filter system100comprises a receptacle chamber for receiving the air filter element100and a service opening in the housing allows to insert or replace a filter element100from the housing. In the embodiments shown onFIG.12toFIG.17, the housing has a cylindrical shape and the service opening is an axial opening in the housing. In other embodiments the housing can have a different shape adapted to for example the shape of the filter medium pack.

FIG.12presents a perspective view of an embodiment of a filter system200according to the disclosure wherein a filter element100is inserted in a housing50and wherein the filter element comprises a foldable/stretchable bridge seal arrangement20as discussed above. InFIG.12, the bridge seal arrangement20is in an unsealed position whereas inFIG.13the bridge seal arrangement20is folded/stretched into a sealed position.FIG.14aandFIG.15bcorrespond to a top view of the air filter system shown onFIG.12andFIG.13, respectively.FIGS.14band15bcorrespond to cross sectional views taken with respect to a plane A shown onFIGS.14aand15a, respectively.

In embodiments of an air filter system200according to the present disclosure, a pre-cleaner75is provided for pre-cleaning the unfiltered air before entering the filter medium pack10. Pre-cleaners for pre-cleaning the air before entering the filter medium pack are known in the art. As illustrated onFIG.16aandFIG.16b, the pre-cleaner75is removably coupled to the housing50. In these embodiments, the second collar-shaped portion20bcomprises a third circumferential sealing surface43configured for cooperating with an inner surface of the pre-cleaner75. Typically the third circumferential sealing surface43and the second circumferential sealing surface42are opposing surfaces. Advantageously, with the bridge seal arrangement20according to the present disclosure, no additional seal is needed for sealing the coupling between the pre-cleaner and the housing of the air filter system.

In embodiments of a filter system200, one or more protruding elements56are attached to the outer sidewall51of the housing, as shown onFIG.12. As further illustrated onFIG.13, when the bridge seal arrangement20comprises one or more handles20eas discussed above, these one or more handles20ecan be coupled to corresponding protruding elements56for keeping the bridge seal arrangement20in place.

FIG.17shows an air filter system200comprising one or more latches80for latching a pre-cleaner75or for latching a filter cover to the housing50. Advantageously, the one or more latches80is coupled with a corresponding handle of the one or more handles20eof the bridge seal arrangement20.

In embodiments, the filter system200comprises a filter cover to for example protect at least part of the axial inlet side of the filter medium pack and wherein the filter cover comprises a circumferential cover portion that is positioned around the second collar-shaped portion20band configured for pressing the second circumferential sealing surface42against the outer sidewall51of the housing.

Method of Servicing a Filter System

The present disclosure also pertains to a method of servicing a filter system for filtering a fluid comprising a housing50having a service opening. The filter system is for example an air filter system for filtering air. The method comprising steps ofproviding a filter element100comprising a filter medium pack10including a filter medium5such as a fluted medium or a pleated medium or any other medium suitable for filtering the fluid,providing a bridge seal arrangement20comprisinga) a first collar-shaped portion20ahaving a first circumferential sealing surface suitable for sealingly coupling to a circumferential side6of the filter medium pack10or suitable for sealingly coupling to a border of an axial inlet side of the filter medium pack10, andb) a second collar-shaped portion20bcoupled to the first collar-shaped portion20a, and having a second circumferential sealing surface suitable for encircling an outer sidewall51of the housing50,sealingly coupling the first circumferential sealing surface to the circumferential side6of the filter medium pack10, or sealingly coupling the first circumferential sealing surface to a border of the axial inlet side of the filter medium pack10,inserting the filter element100in the housing50through the service opening,positioning the filter element100and/or the second collar-shaped portion20bsuch that the second circumferential sealing surface is encircling and is sealingly cooperating with the outer sidewall51of the housing50.
Bridge Seal Arrangements for Inner Wall Coupling

The embodiments of filter elements100for filtering a fluid according to the present disclosure as discussed above are embodiments wherein the bridge seal arrangement20has a second circumferential surface42configured for encircling and sealingly cooperating with the outer sidewall51of the housing of a filter system. An alternative filter element100wherein the bridge seal arrangement20has a circumferential surface configured for encircling and sealingly cooperating with a surface of a tube-shaped wall portion that is located inside the housing of a filter system, is further discussed below. This wall portion is not necessarily a cylindrical tube-shaped portion but it can have any shape including irregular shapes such as a drop shape.

Examples of these alternative embodiments of filter elements100for filtering a fluid are illustrated onFIG.18atoFIG.18dwhere a filter element100is shown that is inserted in a housing50of a filter system. The fluid can be a liquid or a gas, such as for example air.

The embodiment of a filter element for filtering a fluid as illustrated onFIG.18atoFIG.18dcomprises a filter medium pack10extending along a longitudinal axis Z and having a first7and a second8axial side forming an axial boundary of the filter medium pack, and a circumferential side6is forming a radial boundary of the filter medium pack. The filter element100comprises a bridge seal arrangement20having a first ring-shaped or collar-shaped portion20acomprising a first circumferential sealing surface sealingly coupled to the circumferential side6or sealingly coupled to a border of the second axial side8, and a second collar-shaped portion20bcoupled with the first collar-shaped portion20a, and wherein the second collar-shaped portion20bcomprises a second circumferential sealing surface configured for encircling and sealingly cooperating with an outer surface55oof a tube-shaped wall portion55that is located inside the housing50of a filter system200.

In embodiments, as shown onFIG.18atoFIG.18d, the seal20comprises a liner element26coupled to the collar-shaped portion20b. This liner element26facilitates the insertion of the filter element in the housing and to maintain the seal in a firm sealing contact. The thick black arrows indicate a direction for pushing the liner element26such that the seal is well positioned in a sealed position.

The embodiments of filter elements shown onFIG.18candFIG.18dcomprise a filter medium pack10as shown onFIG.1a, i.e., unfiltered fluid is received at the first axial side7and filtered fluid is exiting the filter medium pack at the second axial side8.

The embodiments of filter elements shown onFIG.18aandFIG.18buse a different type of filter medium pack10. Indeed, these filter medium packs10include an annular filter medium radially delimited by an outer side6and an inner side6a. The outer side is permeable for receiving unfiltered fluid, such as air in case the filter element is an air filter element, and this outer side is corresponding to the circumferential side6of the filter medium pack10. The inner side6ais configured for outputting filtered fluid into a cavity30of the annular filter medium. A flange17is closing the first axial side7of the filter medium pack and the second axial side8of the filter medium pack is configured for evacuating filtered fluid from the cavity30.

The disclosure also pertains to a filter system200comprising an alternative filter element as discussed above and as illustrated onFIGS.18ato18d. The filter system200further comprises a housing50comprising an outer sidewall51enclosing or partly enclosing the circumferential side6of the filter medium pack10, and a tube-shaped wall portion55defining an inner radial surface55iand an outer radial surface55o, and wherein the second circumferential sealing surface of the second collar-shaped portion20bis encircling and sealingly cooperating with the surface55oand/or surface55iof the tube-shaped wall portion55located inside the housing.

According to a further aspect of the disclosure, a housing50for a filter element100discussed above in relation toFIGS.18ato18bis provided. The housing50comprises a tube-shaped wall portion55located inside the housing and wherein an outer surface55oof the tube-shaped wall portion is configured for forming an internal sealing surface for cooperating with the second collar-shaped portion20bof the bridge seal arrangement20. As mentioned above, this wall portion is not necessarily a cylindrical tube-shaped portion but it can have any shape including irregular shapes such as a drop shape.