Patent Description:
Gas turbine engines use lubricant to distribute heat, lubricate bearings, reduce friction, etc. This lubricant is circulated through the engine and can carry physical contaminants, such as carbon particles, metal particles, dirt, etc. Accordingly, lubricant is periodically passed through a lubricant filtration unit comprising one or more filters in order to remove at least a portion of the contaminants from the lubricant before the lubricant is circulated back into the engine.

<CIT> discloses a tank-mounted oil filter assembly.

<CIT> discloses a filter element with an off-axis end cap.

<CIT> discloses an in-tank fluid filter with a valve assembly.

<CIT> discloses crankcase ventilation filter arrangements, components, and methods.

According to an aspect of the present invention, there is provided a filter assembly for an engine in accordance with claim <NUM>.

Optionally, a distal end of the annular flange defines a groove, the sealing member received within the groove and biased against the housing.

Optionally, the housing has a first housing section and a second housing section protruding axially from the first housing section, the second housing section ending at the open end, a first diameter of the first housing section less than a second diameter of the second housing section to define a shoulder between the first housing section and the second housing section.

Optionally, the first housing section and the second housing section are non-concentric, a radial dimension of the shoulder is maximal at the circumferential location.

Optionally, a locking engagement is defined between the cover and the filter cartridge to axially lock the cover to the filter cartridge, the locking engagement defined by a cooperation of a leg slidingly receivable within a slot, the leg defined by one of the cover and the filter cartridge, the slot defined by the other of the cover and the filter cartridge.

Optionally, the leg is movable within the slot along a direction normal to the longitudinal axis of the housing.

Optionally, the slot and the leg includes two slots and two legs parallel to each other, each of the two slots slidingly engageable within a respective one of the two slots.

Optionally, the two legs are located at distal ends of two webs protruding from the one of the cover and the filter cartridge along an axial direction relative to the longitudinal axis, the two legs being transverse to the two webs.

Optionally, the two slots are defined by two protrusions extending axially from the other of the cover and the filter cartridge relative to the longitudinal axis, and wherein the two legs extend transversally from the two webs in a direction normal to the longitudinal axis and away form one another, the two slots facing one another.

Optionally, a first stopper is located at an end of the slot and a second stopper at an end of the leg such that the cover is securable to the filter cartridge in a single circumferential orientation of the cover relative to the filter cartridge.

Optionally, the filter cartridge includes an annular flange extending circumferentially around a filtering medium of the filter cartridge, the sealing member located between the annular flange and the housing, wherein the annular flange and the filtering medium are non-concentric.

Optionally, the housing has two non-concentric sections of different diameters thereby defining a shoulder at an intersection between the two non-concentric sections, the cartridge assembly securable to the housing in a single circumferential orientation one relative to the other.

Optionally, the slot and the leg includes two slots and two legs parallel to each other, each of the two legs slidingly engageable within a respective one of the two slots, a spacing defined between the two legs, the spacing oriented toward the oil outlet of the housing when the cartridge assembly is received in the housing at the single circumferential orientation.

<FIG> illustrates a gas turbine engine <NUM> of a type preferably provided for use in subsonic flight, generally comprising in serial flow communication a fan <NUM> through which ambient air is propelled, a compressor section <NUM> for pressurizing the air, a combustor <NUM> in which the compressed air is mixed with fuel and ignited for generating an annular stream of hot combustion gases, and a turbine section <NUM> for extracting energy from the combustion gases. The fan <NUM>, the compressor section <NUM>, and the turbine section <NUM> are rotatable about a central axis <NUM> of the gas turbine engine <NUM>.

The gas turbine engine <NUM> may include a lubrication system S that may include a pump (not shown), lubrication conduits <NUM>, a lubricant reservoir (not shown), and a filter assembly <NUM>. The lubrication system S may also include additional components such as valve(s) (not shown), heat exchangers, etc. The lubricant reservoir may be in fluid flow communication with one or more components of the gas turbine engine <NUM> in need of lubrication, such as, for instance, bearing cavity(ies), gearbox(es), and so on. The pump induces a flow of the lubricant from the lubricant reservoir, to the one or more components of the gas turbine engine <NUM> in need of lubrication, back from the one or more components toward the reservoir and through the filter assembly <NUM>. The filter assembly <NUM> is used to remove contaminants from the lubricant before flowing the lubricant towards the one or more components.

In some configurations, a lubricant filter assembly, which includes a filter cartridge and a housing containing the filter cartridge, are secured to a gas turbine engine in such a way that replacement of the filter cartridge includes pulling the whole filter assembly downward. However, in some other configurations, the location of the lubricant filter assembly is such that there is no room to allow the lubricant filter cartridge to be moved downwardly and must be changed from a top. Moreover, care should be taken to ensure that there are no debris that falls into a clean lubricant outlet of the filter assembly when changing the filter cartridge. There is disclosed herein a filter assembly that may alleviate at least some of the aforementioned problems. More specifically, the disclosed filter assembly uses a filter housing defining a lower section for receiving the filter cartridge and an upper section for receiving a filter cover that is securable to the filter housing and to the filter cartridge. The upper section has a greater diameter than that of the lower section for creating a shoulder against which the filter cover abuts. A keyway engagement may be defined between the filter cartridge and the filter cover to secure the filter cartridge to the filter cover and to create a sealing engagement therebetween.

The clean lubricant outlet of the filter housing may be defined through a peripheral wall of the filter housing. This may prevent debris from falling into said outlet since the outlet may be out of reach of the debris that would fall vertically with gravity upon removal of the filter cartridge and filter cover.

Referring now to <FIG>, the filter assembly <NUM> is shown in greater detail. In the example shown, the filter assembly <NUM> includes a housing <NUM>, a cover <NUM>, and a filter cartridge <NUM>. The filter cartridge <NUM> may be removably secured to the cover <NUM>. The housing <NUM> is configured to contain the filter cartridge <NUM> and the cover <NUM> is configured to sealingly engage the housing <NUM> to create a filter internal volume, or cavity, C within which the lubricant circulates through the filter cartridge <NUM>; the filter cartridge <NUM> being contain within the filter internal volume C of the housing <NUM>. In the depicted example the filter assembly <NUM> has a generally cylindrical shape and extends about a longitudinal axis L. It is understood that other shapes are contemplated without departing from the scope of the present disclosure.

The housing <NUM>, referred simply as housing <NUM> herein below, is configured to receive the filter cartridge <NUM> therein. The filter housing <NUM> has an inlet (not shown) configured for receiving lubricant to be filtered and has an outlet 32a for outputting a flow of filtered lubricant. The housing <NUM> has an upper section 32b (<FIG>) and a lower section 32c (<FIG>). The lower section 32c is configured to receive a major portion, that is more than half herein, of the filter cartridge <NUM>. The outlet 32a of the housing <NUM> is defined at the upper section 32b of the housing <NUM>.

In the example shown, the housing <NUM> has a peripheral wall 32d and an end wall 32e secured to an end of the peripheral wall 32d. The peripheral wall 32d extends circumferentially around the longitudinal axis L of the filter assembly <NUM> and may be cylindrical. The outlet 32a of the housing <NUM> is defined through the peripheral wall 32d at the upper section 32b of the housing <NUM>. Having the outlet 32a of the housing <NUM> locating as such may avoid contaminant to fall into the outlet 32a upon removal of the cover <NUM> and filter cartridge <NUM> during maintenance and replacement of the filter cartridge <NUM>.

As shown more clearly in <FIG>, the outlet 32a of the housing <NUM> is hydraulically connected with a line <NUM>, which may be part of the housing <NUM>. The line <NUM> may extend substantially perpendicularly to the peripheral wall 32d of the housing <NUM> such that the lubricant exits the filter assembly <NUM> in a radial direction, depicted by arrow A on <FIG>, relative to the longitudinal axis L. Alternatively, the line <NUM> may define an angle different than <NUM> degrees relative to the peripheral wall 32d of the housing <NUM>. Arrows A' and A" in <FIG> show that the line <NUM>, and the flow of lubricant exiting the housing <NUM>, may circulate in a radial direction combined with an axial and/or a circumferential direction relative to the longitudinal axis L. The angle the line <NUM> defines with respect to the housing <NUM> may depend upon a location where the filter assembly <NUM> is installed in the gas turbine engine <NUM>.

Still referring to <FIG>, the housing <NUM> defines a shoulder <NUM> at an intersection between the upper and lower sections 32b, 32c of the housing <NUM>. In the embodiment shown, a diameter D1 of the upper section 32b is greater than a diameter D2 of the lower section 32c thereby creating the shoulder <NUM>. As shown in <FIG>, the upper and lower sections 32b, 32c of the housing <NUM> may be cylindrical and may be radially offset from one another. In other words, the upper and lower sections 32b, 32c may not be concentric. Alternatively, the upper and lower sections 32b, 32c may be concentric. In a particular example this offset between the upper and lower sections 32b, 32c of the housing <NUM> may create additional space to slide the filter cartridge <NUM>, when said filter cartridge <NUM> is secured to the cover <NUM>, within the housing <NUM>. This space may be obtained by having the upper and lower sections 32b, 32c of the housing <NUM> being concentric and by increasing a diameter of the upper section 32b relative to that of the lower section 32c. In a particular example this offset between the upper and lower sections 32b, 32c of the housing <NUM> creates the shoulder near the outlet of the housing and may help in protecting the outlet from contaminants that may be released during removal of the filter assembly. In a particular embodiment, the difference in the diameters D1, D2 between the upper and lower sections 32b, 32c of the housing <NUM> creates the shoulder near the outlet of the housing and may help in protecting the outlet from contaminants that may be released during removal of the filter assembly.

Referring more particularly to <FIG>, the filter cartridge <NUM> may include any suitable filtering medium known in the art. In the embodiment shown, the filter cartridge <NUM> has an annular shape and has an outer wall 36a, an inner wall 36b located radially inwardly of the outer wall 36a relative to the longitudinal axis L of the filter assembly <NUM>. Herein, both the outer and inner walls 36a, 36b extends circumferentially about the longitudinal axis L. Herein, the outer and inner walls 36a, 36b are cylindrical, but other shapes are contemplated. The filter cartridge <NUM> may define a central passage 36c that may extend from a lower end 36d to an upper end 36e of the filter cartridge <NUM>. The filter cartridge <NUM> has an inlet 36i and an outlet 36o. In the embodiment shown, the inlet 36i of the filter cartridge <NUM> corresponds to the outer wall 36a, such that the lubricant enters in the filter cartridge <NUM> in a substantially radial direction relative to the longitudinal axis L of the filter assembly <NUM>, and the outlet 36o of the filter cartridge <NUM> corresponds to the central passage 36c at the upper end 36e of the filter cartridge <NUM>, such that the lubricant exits the filter cartridge <NUM> in a substantially axial direction relative to the longitudinal axis of the filter assembly <NUM>. It is understood that the expressions "upper" and "lower" may be interchanged and that the disclosed filter assembly <NUM> may be used upside down, or at any other angle.

A plug <NUM> is secured to the filter cartridge <NUM> at the lower end 36d thereof. The plug <NUM> may be used to prevent lubricant to enter the filter cartridge <NUM> via an annular end face located at the lower end 36d of the filter cartridge <NUM>. In other words, the plug <NUM> may be used to prevent the lubricant from entering the filter cartridge <NUM> in a substantially axial direction. The plug <NUM> may ensure that the oil passes through the filter cartridge <NUM>. Stated differently, the plug <NUM> may prevent lubricant from penetrating the seal from an axial end face of the filter cartridge <NUM>. The filter cartridge <NUM> may be free of the plug <NUM> by having the filter cartridge <NUM> in abutment against a bottom of the housing <NUM> to avoid oil from bypassing the filter cartridge <NUM>. As shown more clearly on <FIG>, a annular groove 38a is defined by the plug <NUM> and may be configured for receiving a seal, such as an O-ring or any other suitable sealing member, therein.

Referring to <FIG> and <FIG>, for installing a cartridge assembly <NUM> of the cover <NUM> and the filter cartridge <NUM> inside the housing <NUM>, the cartridge assembly <NUM> is inserted into the housing <NUM> substantially along an axial direction relative to the longitudinal axis L via an open end 32f (<FIG>) of the housing <NUM>. The cartridge assembly <NUM> is moved relative to the housing <NUM> along the axial direction toward the end wall 32e (<FIG>) of the housing <NUM> until the cover <NUM> is in abutment against the shoulder <NUM> (<FIG>) defined by the housing <NUM>.

As shown in <FIG>, the filter cover <NUM> has an annular flange 34a at a top end thereof and the filter housing <NUM> has an annular flange <NUM> at the open end 32f thereof. The cartridge assembly <NUM> is moved relative to the housing <NUM> along the axial direction toward the end wall 32e (<FIG>) of the housing <NUM> until the cover <NUM> is in abutment against the annular flange <NUM>. Once the cartridge assembly <NUM> is received within the housing <NUM>, the annular flanges <NUM>, 34a of the housing <NUM> and cover <NUM> may be secured to one another to hold the cartridge assembly <NUM> in place relative to the housing <NUM>. Any suitable means to secure the annular flanges <NUM>, 34a to one another may be used. In a particular example, a sealing engagement is created between the annular flanges <NUM>, 34a. Herein, the annular flanges <NUM>, 34a have substantially circular shapes, but other shapes are contemplated. Captive fasteners may be used to assemble the cover <NUM> to the housing <NUM> in order to reduce the chances of FOD. A quick release latch for a tool may be used to secure the cover <NUM> to the housing <NUM>.

Alternatively, or in combination, a sealing engagement may be created between the cover <NUM> and the housing <NUM> at a location proximate the shoulder <NUM> of the housing <NUM>. As shown in <FIG>, an annular groove 34b is defined by the cover <NUM> at a lower end thereof and extends substantially all around the longitudinal axis L. The annular groove 34b is configured to receive a sealing member, such as an O-ring (not shown), therein. In the example shown, the annular groove 34b faces the radial direction such that the sealing member received therein may be compressed radially between the cover <NUM> and the peripheral wall 32d of the housing <NUM>. Alternatively, the annular groove 34b may be defined at an axial end face of the cover <NUM> such that the annular groove 34b faces the axial direction and faces the shoulder <NUM> of the housing <NUM> such that the sealing member received within the annular groove 34b is compressed axially between the housing at the shoulder <NUM> and the cover <NUM>. The cover <NUM> may define two annular grooves each receiving a respective one of two sealing members; the two annular grooves facing respectively in the radial and axial directions relative to the longitudinal axis L.

Referring more particularly to <FIG>, the cover <NUM> may be used to change a direction of the lubricant from being substantially axial relative to the longitudinal axis L to being substantial radial. As aforementioned, the lubricant exits the filter cartridge <NUM> via its outlet 36o along a direction that is substantially axial and the outlet 32a of the housing <NUM> is defined through the peripheral wall 32d and may have at least a radial component relative to the longitudinal axis L. In the embodiment shown, the cover <NUM> is used to redirect the flow of lubricant from being substantially axial to being substantially radial. The cover <NUM> may be used to impart at least a radial and/or at least a circumferential component to the flow of lubricant.

In the depicted example, the cover <NUM> has an internal passage 34c that fluidly connects an inlet 34i of the cover <NUM> to an outlet 34o thereof. The inlet 34i of the cover <NUM> is in fluid communication with the outlet 36o of the filter cartridge <NUM> and the outlet 34o of the cover <NUM> is in fluid communication with the outlet 32a of the housing <NUM> and with the line <NUM> that extends therefrom. The internal passage 34c may be defined by two bores extending partially through a body of the cover <NUM>. Herein, the internal passage 34c includes: a first bore extending substantially axially relative to the longitudinal axis L from the outlet 36o of the filter cartridge <NUM> toward a top end of the cover <NUM> without extending fully through the cover <NUM>; and a second bore extending from the outlet 34o of the cover <NUM> in a substantially radial direction to a distal end of the first bore such that the first and second bore are in fluid communication with one another. Other configurations are contemplated. The shape of the internal passage 34c and its orientation inside the cover may vary, including straight holes, smooth cores.

The circulation of the lubricant through the filter assembly <NUM> is depicted with arrows in <FIG>. The lubricant enters the internal volume C defined by the housing <NUM> and passes through the filter cartridge <NUM> in a substantially radial direction relative to the longitudinal axis L and toward the longitudinal axis L to reach the central passage 36c of the filter cartridge. The lubricant flows axially along the central passage 36c toward the cover <NUM>, enters the internal passage 34c of the cover <NUM> in a substantially axial direction and is re-oriented, within the internal passage 34c of the cover <NUM>, in a direction having at least a radial component relative to the longitudinal axis L. The lubricant exits the filter assembly <NUM> via the outlet 32a of the housing <NUM> and is directed toward other components indeed of lubrication via the line <NUM> that is hydraulically connected to the housing <NUM>.

With time, the filter cartridge <NUM> may decrease in efficiency and may become partially clog by the contaminants it has removed from the lubricant circulating therethrough. Consequently, it may be required to periodically disassemble the filter assembly <NUM> to replace the filter cartridge <NUM>. It may be beneficial to remove the cartridge assembly <NUM> as a single unit.

Referring to <FIG>, while removing the filter cartridge <NUM> from the housing <NUM>, care should be taken to avoid contact between the filter cartridge <NUM> and the housing to avoid rubbing or scrapping the filter cartridge <NUM> against the peripheral wall 32d of the housing <NUM> which may cause contaminants picked up by the filter cartridge <NUM> to detach therefrom an to fall into the housing <NUM>. In the embodiment shown, a guiding feature <NUM> is secured to an end of the filter cartridge <NUM> that is located at the bottom of the housing <NUM> upon the cartridge assembly <NUM> received therein. More specifically, and in the embodiment shown, the guiding feature <NUM> is secured to the plug <NUM> at an external periphery thereof. The guiding feature <NUM> may be provided in the form of one or more tab(s) <NUM> circumferentially distributed about the longitudinal axis L and that bridge a gap G located radially between the filter cartridge <NUM> and the housing <NUM> relative to the longitudinal axis L. The guiding feature <NUM> may therefore limit contacts between the filter cartridge <NUM> and the housing <NUM>. The guiding feature may have various alternative shapes and length. It may be displayed in a circular pattern, or it can be a plate on the whole circumference with slots to allow fluid to pass.

Referring now to <FIG>, a cover and a filter cartridge in accordance with another example are shown generally at <NUM> and <NUM>, respectively. And, referring concurrently to <FIG> that illustrate steps of assembly the cover <NUM> to the filter cartridge <NUM>. To create a locking engagement E (<FIG>) between the cover <NUM> and the filter cartridge <NUM>, the filter cartridge <NUM> defines a tab or a flange 136t that may extend circumferentially around the longitudinal axis L. In the embodiment shown, the flange 136t is located at a distal end of the filter cartridge relative to a distance from the end wall 32e (<FIG>) of the housing <NUM> (<FIG>) in which the filter cartridge <NUM> may be received. The flange 136t has a thickness t1 (<FIG>) taken along the longitudinal axis L. The flange 136t is configured to be received within a groove <NUM> defined by the cover <NUM>. The groove <NUM> is shown in dashed line in <FIG>. The groove <NUM> may have a depth d1 (<FIG>) taken along the longitudinal axis L and that may corresponds substantially to the thickness t1. As shown more particularly on <FIG>, the groove <NUM> is located axially between an axial end face <NUM> of the cover <NUM> and a lip <NUM>, which extends partially around the longitudinal axis L. The groove <NUM> extends radially outwardly relative to the longitudinal axis from an edge of the lip <NUM>. The cover <NUM> thereby defines an opening <NUM>, a periphery of which is depicted in <FIG> with a dashed line. The periphery of the opening <NUM> is defined partially by the lip <NUM>. As shown in <FIG>, the periphery of the opening <NUM> has a shape that corresponds substantially to a shape of the periphery of the flange 136t of the filter cartridge <NUM>. It is understood that the groove and the flange may be defined by the filter cartridge and by the cover in an alternate example without departing from the scope of the present disclosure. In a particular embodiment, the flange 136t may define a chamfer to ease its insertion in the groove.

As shown more specifically in <FIG>, with continued reference to <FIG>, to assemble the filter cartridge <NUM> to the cover <NUM>, the filter cartridge <NUM> and the cover <NUM> are moved one relative to the other along the longitudinal axis L from a disengaged position shown in <FIG> until the flange 136t is received through the opening <NUM> defined by the cover <NUM>, which corresponds to an intermediate position shown in <FIG>. At which point, a sealing member SM, in this case an o-ring <NUM>, which is received within a groove <NUM> (<FIG>) of the filter cartridge <NUM>, becomes biased between the filter cartridge <NUM> and the axial end face <NUM> of the cover. The filter cartridge <NUM> may be in abutment against the axial end face <NUM> of the cover <NUM> upon the o-ring <NUM> biased therebetween. The sealing member SM may create a sealing engagement between the cover <NUM> and the filter cartridge <NUM> to limit fluid that circulates through the central passage 136c (<FIG>) of the filter cartridge <NUM> and toward the cover <NUM> from leaking at an interface between the cover <NUM> and the filter cartridge <NUM>. The sealing member SM may alternatively be a packing, a c-seal, a piston ring with or without a spring, a spring washer, a magnetic seal, or any other type of axial seal.

Referring more particularly to <FIG>, the cover <NUM> may be moved relative to the filter cartridge <NUM> from the intermediary position shown in <FIG> to a locked position shown in <FIG>. In the embodiment shown, the cover <NUM> and filter cartridge <NUM> are moved one relative to the other along a radial direction R (<FIG>) relative to the longitudinal axis L. In other words, the cover <NUM> and the filter cartridge <NUM> are translated one relative to the other to move them from the intermediary position to the locked position of <FIG>. In the locked position, at least a portion of the flange 136t is received within the groove <NUM> of the cover <NUM>. This creates the locking engagement E that may limit axial movement of the cover <NUM> relative to the filter cartridge <NUM> along the longitudinal axis L. The cooperation of the flange 136t and the groove <NUM> may block axial movements of the cover <NUM> and the filter cartridge <NUM> one relative to the other. In the embodiment shown, the flange 136t becomes sandwiched between the lip <NUM> of the cover <NUM> and the axial end face <NUM> of the cover <NUM>. In the embodiment shown, in the locked position depicted in <FIG>, the lip <NUM> of the cover is slidingly received within a groove <NUM> defined by the cartridge proximate the flange 136t upon the flange 136t received within the groove <NUM> of the cover <NUM>.

In an alternate example, the cover <NUM> and the filter cartridge <NUM> may be rotated one relative to the other about the longitudinal axis L to move the cover and cartridge from the intermediate position to the locked position. Other configurations are contemplated without departing from the scope of the present disclosure. Once the cover <NUM> and the filter cartridge <NUM> are in the locked position, the filter cartridge assembly may be moved within the housing <NUM> (<FIG>) using a handle <NUM> (<FIG>) located on top of the cover <NUM>. Other means of manipulating the cartridge assembly are contemplated.

Referring back to <FIG>, the shape of the opening <NUM> is configured to maximize a surface contact, or retention surface, area between the lip <NUM> and the flange 136t of the cover <NUM> and the filter cartridge <NUM> respectively. In the example shown, the opening <NUM> defines at least one tooth, two teeth 134t in the embodiment shown, and at least one slot, two slots <NUM> in the embodiment shown. Correspondingly, the flange 136t may define at least one slot, two slots <NUM> in the embodiment shown, and at least one tooth, two teeth 136q in the embodiment shown. The teeth 136q of the flange 136t are slidably received within the slots <NUM> of the opening <NUM> and the teeth 134t of the opening <NUM> are slidingly receive within the slots <NUM> of the flange 136t. In other words, the opening <NUM> may have a keyway shape corresponding to a shape of the flange 136t to allow one to be received within the other. In the example shown, the opening <NUM> and the flange 136t are non-axisymmetric and may define a symmetry plane containing the longitudinal axis L.

Referring now to <FIG>, alternative examples of the cover are shown generally at <NUM> and <NUM>, respectively. The cover <NUM>, <NUM> may different from the cover <NUM> of <FIG> by the shape of their opening <NUM>, <NUM>. As shown, a number of teeth/slot may be varied. Any other suitable shape may be used. The shape of the opening of the cover and that of the flange may be used to ensure that the filter cartridge and cover are matingly engageable to one another solely in one orientation of the cover relative to the filter cartridge.

Referring more particularly to <FIG>, the opening <NUM> includes first and second curved sections 234m1, 234m2 diametrically opposed to one another; a diameter the first curved section 234m1 being greater than that of the second section 234m2. The first and second curved sections 234m1, 234m2 are connected via a middle section 234m3. The middle section 234m3 defines two slots 234m4 and two teeth 234m5; the two slots facing one another and the two teeth facing one another. In the embodiment shown, the middle section is tangent to the second section. Other configurations are contemplated. For instance, in <FIG>, the middle section is straight and a junction between the middle and second sections defines a kink. Referring more particularly to <FIG>, the opening <NUM> is similar to the opening <NUM> described above with reference to <FIG>, but the middle section 334m3 is free of the teeth and slot.

The different shapes of the opening and corresponding flange may be selected to provide a uniformity of a biasing force exerted by the interaction of the cover and filter cartridge on the sealing member when in the locked position shown in <FIG>. The shape of the opening may dictate a surface area used to retain the filter as well as its disposition near the seal. The shape shown in <FIG> may offer a larger retaining surface. The teeth may be used as a mean to prevent or limit the rotation of the filter cartridge <NUM> relative to the cover <NUM> should a sliding motion is used to disassemble the filter cartridge <NUM> from the cover <NUM>.

Referring to <FIG>, a cartridge assembly in accordance with another example is shown generally at <NUM>. The cartridge assembly <NUM> includes a cover which may correspond to the cover <NUM> described above with reference to <FIG> and a filter cartridge <NUM> in accordance with another embodiment. In some cases, it may be required to grab the filter cartridge <NUM> for either assisting its removal from the housing <NUM> (<FIG>) and/or to orient it with respect to the cover <NUM>. However, the filtering medium of the cartridge may be soft and grabbing it directly may deform it, which may impair its filtering efficiency.

In the example shown, the filter cartridge <NUM> includes at least one, two in the example shown, holding tabs 436n, each of which may be L-shaped including a radial protrusion 436n1 extending radially away from a proximal end of the filter cartridge <NUM> and an axial protrusion 436n2 protruding axially from a distal free end of the radial protrusion 436n1. The axial protrusions 436n2 defines a surface 436n3 against which a user may lay his/her finger to manipulate the filter cartridge <NUM>. In the example shown, the axial protrusions 436n2 extends axially relative to the longitudinal axis L toward the end wall of the housing <NUM> (<FIG>) when received therein. As shown in <FIG>, the holding tabs 436n are axially offset from the flange 136t and groove <NUM> defined by the filter cartridge <NUM>.

The support or holding tabs 436n may be used if the pinch (e.g. biasing force) between the cover <NUM> and the sealing member SM (<FIG>) is high enough to expect a deformation of the filter cartridge <NUM> during assembly. The tabs 436n may ease the grip by hand or tool and may be configured to re-direct the load path outside the filter element (e.g. filtering medium). The support may or may not serve as a filter guiding feature once in the locked position. In other words, the tabs may be in abutment against the wall of the housing to maintain the cartridge concentric with the housing.

Referring to <FIG>, another example of a cartridge assembly is shown generally at <NUM>. The assembly <NUM> includes a cover <NUM> and a filter cartridge <NUM>. In the example shown, the cover <NUM> defines two tabs 534t that are diametrically opposed to one another and the filter cartridge <NUM> defines grooves <NUM>, two in the embodiment shown, that are diametrically opposed to one another. Each of the tabs 534t of the cover <NUM> may be slidingly received within a respective one of the grooves <NUM> of the filter cartridge <NUM>. It is understood that the cover may define the grooves and the cartridge may define the tab in an alternate example.

<FIG> illustrate the assembly <NUM> in the disengaged position and <FIG> illustrates the assembly in the locked position in which the sealing member SM is compressed between the cover <NUM> and the filter cartridge <NUM>. To create the locking engagement E between the cover <NUM> and the filter cartridge <NUM>, the cover and cartridge are moved one relative to the other until the grooves <NUM> are in register with the tabs 534t. At which point, the cover <NUM> and the filter cartridge <NUM> are moved one relative to the other in a radial direction R relative to the longitudinal axis L to slide the tabs 534t within the grooves <NUM>.

Referring to <FIG>, another example of a cartridge assembly is shown generally at <NUM>. The assembly <NUM> includes a cover <NUM>, a filter cartridge <NUM>, and a locking member also referred to as a fork <NUM>. In the embodiment shown, the cover <NUM> defines an elongated slot <NUM> dimensioned for receiving the fork <NUM>. The filter cartridge <NUM> defines a tab 636t at an extremity of the filter cartridge <NUM>. A recess 636r is defined by the filter cartridge <NUM> proximate the tab 636t. The cover <NUM> has an opening <NUM> suitably dimensioned for receiving the tab 636t of the filter cartridge <NUM>.

To create the locking engagement E between the cover <NUM> and the filter cartridge <NUM>, the cover <NUM> and the filter cartridge <NUM> are moved one relative to the other along the longitudinal axis L until the tab 636t of the filter cartridge <NUM> is received within the opening <NUM> of the cover <NUM>. At which point, the fork <NUM> may be inserted in the elongated slot <NUM> of the cover <NUM> in a radial direction R relative to the longitudinal axis L. The fork <NUM> thereby locks the tab 636t of the filter cartridge <NUM> within the cover <NUM>. More specifically, the fork <NUM> has an inner dimension suitably dimensioned to be able to be received within the recess 636r of the filter cartridge <NUM> and that is less than a diameter of the tab 636t, and has an outer dimension that is greater than a dimension of the opening <NUM> of the cover <NUM> such that, upon the fork <NUM> received within the elongated slot <NUM> of the cover <NUM>, movement of the cover <NUM> relative to the filter cartridge <NUM> along the longitudinal axis L is limited by the fork <NUM> and, more specifically, limited by the interaction of the fork <NUM> with the tab 636t of the filter cartridge <NUM> and with an annular flange 634f of the cover <NUM>, which defines the opening <NUM> of the cover <NUM>. In other words, the fork <NUM> is configured to be in abutment with both of the tab 636t of the filter cartridge <NUM> and with the annular flange 634f of the cover <NUM> to limit movements of the cover <NUM> relative to the filter cartridge <NUM>.

Referring now to <FIG>, an embodiment of a filter assembly according to the present invention is shown at <NUM>.

The filter assembly <NUM> includes a housing <NUM> and a cartridge assembly <NUM> receivable in the housing <NUM>. The housing <NUM> extends along a longitudinal axis L. The cartridge assembly <NUM> includes a cover <NUM> sealingly engageable to the housing <NUM> to close an open end 732a of the housing <NUM>. The cartridge assembly <NUM> includes a filter cartridge <NUM>, which includes a filtering medium or core, provided here in annular form, for removing unwanted particles from oil flowing through the filter assembly <NUM>.

As shown in <FIG>, the housing <NUM> has an inlet 732i, which is shown here defined through a bottom wall of the housing <NUM>, but may alternatively be defined through a side or peripheral wall of the housing <NUM>. The inlet 732i is hydraulically connectable to an oil system of the gas turbine engine <NUM> (<FIG>) for receiving a flow of oil that may contain debris to be removed. The housing <NUM> has an outlet 732o, which is defined through a side wall of the housing <NUM> proximate the open end 732a of the housing <NUM> as will be explained below. The housing <NUM> may be similar to the housing <NUM> described above with reference to <FIG>.

Referring to <FIG>, the housing <NUM> defines an internal volume C sized for receiving at least a portion of the cartridge assembly <NUM> (<FIG>). A first sealing engagement is defined between the cover <NUM> and the housing <NUM> to close the open end 732a of the housing <NUM>. This first sealing engagement may be provided by a first sealing member <NUM>, such as an O-ring, received within a groove 734a defined by the cover <NUM>. The groove 734a and the first sealing member <NUM> may extend circumferentially all around the longitudinal axis L. The first sealing member 734a may be radially biased between an inner face of the housing <NUM> and the cover <NUM>. The groove 734a may alternatively be defined by the housing <NUM>. It will be appreciated that, alternatively or in combination, the sealing engagement may be defined by annular abutting faces of the cover <NUM> and the housing <NUM> at the open end 732a of the housing <NUM>. This first sealing engagement limits oil from leaking outside the internal volume V of the housing <NUM>. Any suitable means may be used for sealing the cover <NUM> to the housing <NUM> such as, for instance, face seal, radial seal, corner packing, gasket, or any combination of the above. A mean may be used to retain the cover <NUM> axially. This mean may include, for instance, a bolded joint including bolds, studs and nuts. A threading engagement between the cove <NUM> and the housing <NUM> is contemplated in conjunction with an O-ring or other suitable sealing means.

In the embodiment shown, the cover <NUM> is secured to the housing <NUM> via an annular flange <NUM> of the cover <NUM> in abutment against an annular flange <NUM> of the housing <NUM>; the annular flange <NUM> of the housing <NUM> extending around the open end 732a of the housing <NUM>. The annular flange <NUM> of the housing <NUM> may be fastened to the annular flange <NUM> of the cover <NUM> using any suitable fasteners. A sealing engagement may be provided between those two flanges <NUM>, <NUM> via a gasket or a face seal located between the two flanges <NUM>, <NUM>.

A second sealing engagement is defined between the filter cartridge <NUM> and the housing <NUM> to divide the internal volume C in a first zone, or un-filtered zone Z1, and a second zone, or filtered zone Z2. The used oil flows in the filter assembly <NUM> via the inlet 732i defined by the housing <NUM> and reaches the un-filtered zone Z1. The oil then flows through the filtering medium of the filter cartridge <NUM> in a substantially radial direction relative to the longitudinal axis L until it reaches an inner passage 736a of the filter cartridge <NUM>. The oil then flows to the filtered zone Z2 via which it exits the filter assembly <NUM> via the outlet 732o defined by the housing <NUM>. The inlet 732i communicates with the unfiltered zone Z1 and the outlet 732o communicates with the filtered zone Z2. The two zones communicate together through the filtering medium of the filter cartridge <NUM>.

Considering that both clean and used oil flow in the filter assembly <NUM>, it may be required to isolate these two zones to prevent used oil from flowing out of the housing <NUM> via the outlet 732o. In the embodiment shown, a second sealing member <NUM> is provided between the housing <NUM> and the filter cartridge <NUM>. In the depicted embodiment, the second sealing member <NUM>, which may be an O-ring, is received within a groove 736b defined by the filter cartridge <NUM>. More specifically, the filter cartridge <NUM> includes a flange 736c that extends in a direction having a radial component relative to the longitudinal axis L. The flange 736c may be monolithic with a top portion of the filter cartridge <NUM>. The flange 736c extends radially beyond the filtering medium in the embodiment shown. The flange 736c extends radially from the filtering medium and defines the groove 736b at its distal end. The groove 736b extends circumferentially all around the longitudinal axis L. The second sealing member <NUM> is therefore biased radially between an inner face of the housing <NUM> and the flange 736c to define a sealing engagement between the filter cartridge <NUM> and the housing <NUM>. Therefore, the oil may flow from the unfiltered zone Z1 to the filtered zone Z2 solely through the filtering medium of the filter cartridge <NUM>. It will be appreciated that any other sealing member may be used such as a C-seal, a face seal, a tight fit, and so on.

As previously explained with reference to <FIG>, the housing <NUM> has an upper section 732u and a lower section <NUM>. The lower section <NUM> is sized to receive a major portion, that is more than half herein, of the filter cartridge <NUM>. The outlet 732o of the housing <NUM> is defined at the upper section 732u of the housing <NUM>. The lower section <NUM> has a diameter less than that of the upper section 732u to define an shoulder <NUM> at an intersection between the lower section <NUM> and the upper section 732u. The shoulder <NUM> faces a direction having an axial component relative to the longitudinal axis L and faces the open end 732a of the housing <NUM>. The distal end of the annular flange 736c that defines the groove 736b receiving the second sealing member <NUM> may be in abutment against the shoulder <NUM>. In the present case, an axial position of the filter cartridge <NUM> relative to the housing <NUM> is established by the cover <NUM> and, more particularly, by the abutment of the flange <NUM> of the cover against the flange <NUM> of the housing <NUM>; a gap may remain between the annular flange 736c of the filter cartridge <NUM> and the shoulder <NUM> of the housing <NUM>. It will be appreciated that, alternatively or in combination, the groove may be located such that the second sealing member <NUM> is located axially between the flange 736c and the shoulder <NUM> and biased axially therebetween.

Still referring to <FIG>, in the embodiment shown, the upper section 732u and the lower section <NUM> are radially offset from one another. In other words, the upper section 732u and the lower section <NUM> are non-concentric. They have respective central axis that may be parallel, but spaced apart from one another. Hence, a dimension of the shoulder <NUM> may vary around the longitudinal axis L. The dimension of the shoulder <NUM>, which corresponds to a radial dimension relative to the longitudinal axis L, is maximal at a first location L1 and minimal at a second location L2. The first location L1 and the second location L2 are diametrically opposed from one another. As shown in <FIG>, the first location L1 where the radial dimension of the shoulder <NUM> is maximal is circumferentially aligned with the outlet 732o of the housing <NUM>. As explained below, this may maximize clearance between the filtering medium of the filter cartridge <NUM> and the outlet 732o thereby minimizing debris falling into the outlet 732o upon replacement of the filter cartridge <NUM>.

In an alternate embodiment, the annular flange 736c and the groove 734b of the filter cartridge <NUM> may have a shape differing than that of the filtering medium of the filter cartridge <NUM>. For instance, the annular flange 736c may be oval-shaped. The housing may be suitably shaped to accommodate this oval-shaped annular flange. The oval-shape of the annular flange may be centered with regards to the housing <NUM>. Alternatively, the oval-shape may be offset from a center of the housing <NUM>.

Moreover, the flange 736c of the filter cartridge <NUM> and the filtering medium, and its inner passage 736a, are non-concentric from one another. Again, they may have respective central axis that are parallel, but spaced apart from one another. Consequently, a radial distance relative to the longitudinal axis L between the groove 736b, which receives the second sealing member <NUM>, and the filtering medium is maximal at the first location L1, which registers with the outlet 732o, and minimal at the second location L2, which is diametrically opposed to the first location L1. This may ensure uniform radial clearance between the housing <NUM> and the filtering medium of the filter cartridge <NUM> all around the circumference of the filtering medium. Moreover, this may further contribute in increasing a distance between the filtering medium and the outlet 732o of the housing <NUM>, which may further help in keeping the outlet 732o free of falling debris from the filtering medium.

Referring more particularly to <FIG>, a locking engagement LE is defined between the cover <NUM> and the filter cartridge <NUM>. The locking engagement LE is used to secure the filter cartridge <NUM> to the cover <NUM> and to limit an axial movement of the cover <NUM> relative to the filter cartridge <NUM> relative to the longitudinal axis L. In the depicted embodiment, the locking engagement LE is defined by a cooperation of one or more legs into one or more slots.

The filter cartridge <NUM> includes top wall 736d that defines the flange 736c, and from which protrudes the filtering medium. The top wall 736d has an aperture 736e (<FIG>) defined therethrough. The aperture 736e communicates with the inner passage 736a of the filtering medium to allow clean oil to flow from the first zone Z1 to the second zone Z2. As shown in <FIG> and <FIG>, the filter cartridge <NUM> includes two protrusions 736p each extending from the top wall 736d along a direction having an axial component relative to the longitudinal axis L and away from the filtering medium. The two protrusions 736p are spaced apart from one another and are disposed on respective opposite sides of the aperture 736e. In other words, the aperture 736e is between the two protrusions 736p. It will be appreciated that, in one embodiment, only one protrusion may be provided. Each of the two protrusions 736p defines a respective one of slots <NUM> that are engageable by the cover <NUM> as will be explained below. The two slots <NUM> face one another, they may alternatively face away from on another. In the depicted embodiment, the two slots <NUM> are parallel to one another, but other configurations are contemplated.

The cover <NUM> includes two legs <NUM> located at distal ends of two webs 734w. The two legs <NUM> are transverse to the two webs 734w. The two legs extend away from one another, although they may alternatively face toward one another. Each of the two legs <NUM> is sized to be slidingly received within a respective one of the two slots <NUM> along a direction that may be normal to the longitudinal axis L. The locking engagement LE is defined by the two legs <NUM> received within the two slots <NUM> and is shown in <FIG>. As illustrated, each of the two protrusions 736p defines an abutment face that faces and abuts a respective one of the two legs <NUM> when the two legs <NUM> are received into the two slots <NUM>. It will be appreciated that, in an alternate embodiment, the one or more legs may be defined by the filter cartridge <NUM> and the one or more slots may be defined by the cover <NUM>. In some other configurations, a T-shaped groove may be defined by one of the cover <NUM> and the filter cartridge <NUM> and sized to receive a correspondingly shaped member defined by the other of the cover <NUM> and the filter cartridge <NUM> to lock the cover <NUM> to the filter cartridge <NUM>. Any other suitable means of locking axially the cover <NUM> to the filter cartridge <NUM> are contemplated without departing from the scope of the present disclosure. In some cases, a rotation of the cover <NUM> relative to the filter cartridge <NUM> may lock these two components together. Dogs and slots may be used for this purpose. A combination of axial and radial movements may be used to axially lock the cover <NUM> to the filter cartridge <NUM>. The legs <NUM> may be reinforced by ribs or bent sections to improve performance in compression during assembly and in tension during dis-assembly.

Referring more particularly to <FIG>, the two slots <NUM> are closed-ended. In other words, stoppers 736t are located at ends of the two slots <NUM>. Similarly, stoppers 734t are located at ends of the legs <NUM>. Hence, the cover <NUM> is securable to the filter cartridge <NUM> in solely a single relative circumferential orientation one relative to the other. In other words, the slots <NUM> of the filter cartridge <NUM> define each a single inlet via which the legs <NUM> may be inserted. And, the legs <NUM> are blocked at one end by the stoppers 734t. Consequently, this configuration may deter a user from mis-assembling the cover <NUM> to the filter cartridge <NUM> in a wrong relative orientation.

Moreover, because of the non-concentricity of the upper section 732u and the lower section <NUM> of the housing <NUM>, the cartridge assembly <NUM> may be received into the housing <NUM> in a single relative orientation to ensure that the location L1, where the radial dimension of the flange 736c (<FIG>) of the filter cartridge <NUM> is circumferentially aligned with the outlet 732o of the housing <NUM> and aligned with the location L1 where the radial dimension of the shoulder <NUM> is maximal.

In the embodiment shown, if one were to insert the cartridge assembly <NUM> in the wrong orientation relative to the housing <NUM>, the cover <NUM> might not be able to be received into the open end 732a of the housing <NUM>. This may prevent the annular flange <NUM> of the cover <NUM> from abutting the annular flange <NUM> of the housing <NUM>. This may also prevent the first sealing member <NUM> from sealingly engaging the housing <NUM>. This may indicate to a user that the orientation is incorrect and, consequently, the user may rotate the housing <NUM> relative to the cartridge assembly <NUM> until the proper orientation is achieved. Additionally, or in combination, a bolt pattern to fasten the cover <NUM> to the housing <NUM> may be designed such that respective holes are in register in a single relative orientation of the cover <NUM> relative to the housing <NUM>.

As shown in <FIG>, when the cover <NUM> is secured to the filter cartridge <NUM> in the correct orientation, and when the cartridge assembly <NUM> is received into the housing <NUM> in the correct orientation, a space between the two webs 734w is aligned with the outlet 732o of the housing <NUM>. This may minimize pressure drops of the oil flowing through the filter assembly <NUM> since the oil may flow substantially uninterrupted from the inner passage 736a of the filtering medium to the outlet 732o of the housing <NUM>. The spacing is therefore circumferentially aligned with the location L1, to face the outlet 732o, where the radial dimensions of both the flange 736c of the filter cartridge <NUM> and of the shoulder <NUM> between the upper section 732u and lower section <NUM> of the housing <NUM> are maximal.

Referring now to <FIG>, steps of assembling the filter assembly <NUM> are shown. As illustrated in <FIG>, the cover <NUM> is attached to the filter cartridge <NUM> by first rotating the cover <NUM> relative to the filter cartridge <NUM> until the legs <NUM> are aligned with the slots <NUM> in the proper orientation. Then, the cover <NUM> may be translated relative to the filter cartridge <NUM> along direction D1 to insert the legs <NUM> into the slots <NUM>. The direction D1 is substantially transverse to the longitudinal axis L. In <FIG>, the cartridge assembly <NUM> is moved relative to housing <NUM> along direction D2, which is substantially parallel to the longitudinal axis L, to insert the filtering medium of the filter cartridge <NUM> into the housing <NUM>. The cartridge assembly <NUM> may be rotated relative to the housing <NUM> about the longitudinal axis L until the spacing between the legs <NUM> faces the outlet 732o, and until the location L1 where the radial dimension of the flange 736c of the filter cartridge <NUM> is maximum is substantially circumferentially aligned with the outlet 732o of the housing <NUM>. The cartridge assembly <NUM> is moved relative to the housing <NUM> until the flange <NUM> of the cover <NUM> abuts the flange <NUM> of the housing <NUM> as explained above and until the sealing engagement between the filter cartridge <NUM> and the housing <NUM> is created. This results in the sealing engagement between the cover <NUM> and the housing <NUM>. At which point, the cover <NUM> may be fastened to the housing <NUM> using the bores 734d defined through the annular flange <NUM> of the cover <NUM>. The first and second sealing members <NUM>, <NUM> are therefore biased, radially in the embodiment shown, to provide the required sealing engagement.

The disclosed filter assembly <NUM> may provide protection against contaminants, ease maintenance by removing the filter with the filter cover, minimize risks of disassembly in operation or mis-assembly that might lead to improper sealing between inlet and outlet. The filter legs may prevent the second sealing member <NUM> from disengaging and may allow to disassemble it with the cover. The legs may also locate the filter angularly and prevent the filter to be assembled before the cover. The stoppers on the filter and cover further limit the angular position.

In an alternate embodiment, the filter cartridge may be installed in the housing <NUM> without pre-assembling the cover to the filter cartridge. The cover may therefore be used to axially lock a position of the filter cartridge relative to the housing to maintain a sealing engagement between the second sealing member <NUM> and the housing <NUM>.

As part of the regular scheduled maintenance of an aircraft turbine engine, the lubricant/fuel filters may have to be replaced. It may be important that the filters are easily accessible as this may minimize the risk of introducing debris into the engine. On a twin engine application, the filter may have to be accessible from both sides of the engine. The disclosed filter assembly may minimize the risk of disassembly or mis-assembly that may lead to improper sealing between the inlet and outlet.

In some cases, filter upright position may be the most desirable one. The outlet may need to be protected against falling debris and filter contaminants. There may be an interest to ease the maintenance by removing the filter with the filter cover. The disclosed filter assemblies may be able to hide the outlet of the filter into the filter cover; ensure a connection to the engine that may not expose the outlet; and ensure a sub-assembly (e.g., cartridge assembly <NUM>) between the filter cartridge and the filter cover that may be required by design to assemble the sub-assembly in the filter housing. These may be achieved by a stepped housing <NUM>; a filter assembly sequence that may include an axial seal and a keyway shape interface; and/or filter guiding features.

A stepped filter housing may allow a filter to be mounted vertically upwards. The cover may transfer the fluid to a horizontal connection located on the outlet bore further from the filter bore. This recess may allow the connection to be protected against the filter contaminants in case contaminants are scraped on the filter housing bore during maintenance. The horizontal orientation may minimize the possibility of introducing dirt back into the engine. This step may be achieved by two concentric or non-concentric bores, or by a stepped bore of different shape. If the filter is mounted near the top of the engine it may be equally accessible from both sides of the engine.

The filter assembly sequence may ensure a minimized disassembly or mis-assembly risk when installed in the housing while allowing to remove the filter with the filter cover. The filter may feature a keyway-shaped flange and an axial seal. The filter cover may feature a keyway-shape slot and a groove. To assemble, the keyway-shaped flange and groove may be aligned and engaged. The filter may slide transversely to apply an axial load on the seal and to fix the filter on the filter cover. The assembly sequence may ensure the axial seal is loaded and the sub-assembly can only be assembled in the housing if the second step is completed.

The filter guiding features may ensure the filter is properly assembled and sealed on the filter cover when finally assembled in the housing. If the guiding features are located at the bottom of the filter, they may ensure the filter remains concentric to the filter bore in order to reduce the risk of scraping the contaminant from the filter to the housing outlet when the filter is being removed.

The stepped housing bore may allow for additional radial space to slide the filter on the cover. The filter guiding feature may ensure the filter remains assembled after final assembly when used with a face seal.

The disclosed filter assemblies and cartridge assemblies may ease maintainability since securing the outlet from debris may allow to use an upright positioned filter. This may be preferable from a maintenance perspective since the bolts and filter may be directly visible/accessible from the top facilitating their access from both sides of the engine. The disclosed filter assemblies and cartridge assemblies may ease packaging since they may minimize the overall envelope required in the nacelle when mounted near the top and when the nacelle door is located at the top. The disclosed filter assemblies and cartridge assemblies may ease maintenance since they allow to remove the filter with the filter cover which may avoid the use of standard or special tooling to remove the filter.

Claim 1:
A filter assembly (<NUM>) for an engine (<NUM>), comprising:
a housing (<NUM>) having a longitudinal axis (L) and defining an internal volume (C), the housing (<NUM>) having an open end (732a), the housing (<NUM>) defining an oil inlet (732i) and an oil outlet (732o), the internal volume (C) having a first zone (Z1) and a second zone (Z2), the first zone (Z1) in fluid communication with the oil inlet (732i), the second zone (Z2) in fluid communication with the oil outlet (732o);
a cartridge assembly (<NUM>) having a filter cartridge (<NUM>) extending into the internal volume (C), and a cover (<NUM>) sealingly engageable to the housing (<NUM>) to close the open end (732a) of the housing (<NUM>), the filter cartridge (<NUM>) axially locked in the housing (<NUM>) by the cover (<NUM>), the cover (<NUM>) removably securable to the housing (<NUM>) to allow replacement of the filter cartridge (<NUM>) via the open end (732a); and
a sealing member (<NUM>) between the housing (<NUM>) and the filter cartridge (<NUM>), the sealing member (<NUM>) separating the first zone (Z1) from the second zone (Z2) such that the first zone (Z1) communicates with the second zone (Z2) through the filter cartridge (<NUM>),
wherein the filter cartridge (<NUM>) includes an annular flange (736c) extending circumferentially around a filtering medium of the filter cartridge (<NUM>), the sealing member (<NUM>) located between the annular flange (736c) and the housing (<NUM>),
wherein a radial dimension of the annular flange (736c) relative to the longitudinal axis (L) is maximal at a circumferential location (L1) relative to the longitudinal axis (L), the circumferential location (L1) registering with the oil outlet (732o) of the housing (<NUM>),
characterised in that:
the annular flange (736c) and the filtering medium are non-concentric.