WO2016142735A1

WO2016142735A1 - Liquid filter and vehicle comprising such an liquid filter

Info

Publication number: WO2016142735A1
Application number: PCT/IB2015/001024
Authority: WO
Inventors: Ladislav VERBO
Original assignee: Volvo Truck Corporation
Priority date: 2015-03-12
Filing date: 2015-03-12
Publication date: 2016-09-15

Abstract

A liquid filter (1) or a filter sub-assembly (11) that is designed to be mounted in the filter chamber of a liquid filter (1), wherein the filter chamber is delimited by a filter housing (12) having a peripheral wall (120), a bottom wall (122) and is also delimited by a removable filter cap (18) that closes a main filter opening (125) of the filter housing (12) through which the filter sub-assembly (11) can be removed. The filter sub-assembly (11) comprises : a liquid retention member (14) that comprises an outer tubular wall (140), an inner tubular wall (142) arranged in the outer tubular wall (140) and an annular bottom wall (144) that extends radially between the inner and the outer tubular walls (142, 140), the outer tubular wall (140), the inner tubular wall (142) and the annular bottom wall (144) form together an annular volume (V14), an annular filter element (16) located in the annular volume (V14) of the liquid retention member (14). The annular bottom wall (144) is liquid-tight. The outer tubular wall (140) and the inner tubular wall (142) are liquid-tight over a height (h142), measured parallel to the central axis (Z12) from the annular bottom wall, that is superior to 50%, preferably 75% of the filter element height (h140). The filter sub-assembly (11) is designed as a removable part of the liquid filter (1) and can be removed from the filter housing (12) through the main opening (125).

Description

LIQUID FILTER AND VEHICLE COMPRISING SUCH AN LIQUID FILTER

TECHNICAL FIELD OF THE INVENTION

The invention concerns a liquid filter, liquid retention member and a filter sub- assembly intended to be used in such a liquid filter used to clean liquid circulating in the engine of a vehicle such as fuel or oil. The invention also concerns a vehicle equipped with such a liquid filter.

BACKGROUND OF THE INVENTION

The invention can be applied in heavy-duty vehicles, such as trucks, buses and construction equipment. Although the invention will be described with respect to a truck, the invention is not restricted to this particular vehicle, but may also be used in other vehicles, such as cars.

In the automotive industry, it is known to equip a vehicle with at least one liquid filter to clean oil used to lubricate mechanical components arranged in the engine of the vehicle. Indeed, oil flowing in the engine compartment is polluted by metallic rubble and other particles coming from friction between mechanical components of the engine and needs to be cleaned so as to avoid clogging the engine.

In known manner, a liquid filter comprises :

· a filter housing closed by a filter cap. The filter housing and the filter cap delimit a filter chamber,

• a removable filter element having globally a cylindrical or a tubular shape around a central axis and that is arranged is the filter chamber.

The filter housing can be fixed on a filter base or the base can be part of the filter housing.

The filter element comprises a tubular grid which supports a filter medium having an annular shape and that is generally folded around the tubular grid. The tubular grid and the filter media form a tubular shape whose axial ends are closed by annular caps. The filter element delimits in the filter chamber an upstream portion, that is upstream of the filter element, and a downstream portion, that is downstream of the filter element, which are also known respectively as an unclean zone and a clean zone or as an unfiltered zone and a filtered zone. The filter cap is removably attached, generally screwed, to the filter housing. When it is needed to change the filter element, during a filter maintenance operation, the housing cap and the filter element are removed together. When removing the filter element, the filtering liquid may splash below and around the filter element and pollute the environment. In particular, the filtering liquid may splash on the engine block or on other equipment, such as electric equipment of the vehicle that can be damaged by splashing liquid.

Moreover, liquid, for instance oil, splashing from inside the filter housing may be very hot, thereby inducing a risk of burning for the user.

In order to solve this drawback, US-B-2 886 180 provides an oil filter with oil retention means. This oil filter comprises a base, a housing and a cover assembly. The housing has a filter chamber within which is arranged a filter element. This filter element includes a filter medium that is made of pervious resin impregnated paper and that is retained by outer and inner tubular perforated wrappers of the filter element. The inner and outer wrappers are connected by two non-permeable-end caps fixed at the axial ends of both wrappers. The filter medium is arranged in an annular volume delimited between a first and a second tube of a filter element secured to the housing, the second tube being disposed coaxially inside the first tube. The first and the second tubes are secured to a bottom wall and delimit two separate chambers disposed on both side of the filter medium. A first chamber is configured to retain a quantity of filtered liquid while a second chamber is configured to retain a quantity of unfiltered liquid. In order to ensure that substantially all of the sediment is drained from the second chamber when the filter element is removed, the bottom wall of the filter element is provided with a plurality of apertures, which communicate with a liquid supply chamber. In operating condition, the bottom cap of the filter element seals the apertures of the bottom wall of the filter element. However, when the filter element is fouled and is removed, the supply of unfiltered liquid retained in the second chamber is immediately drained therefrom and discharged to the inlet side of the filter.

The major drawback with this construction is that, when the filter element is removed, liquid may splash around since the inner and outer wrappers are radially perforated. Consequently, the replacement of the filter element may be dirty.

SUMMARY OF THE INVENTION

An object of the invention is to provide a liquid retention member, a filter subassembly and a liquid filter which limit filtering liquid from splashing around or below the filter element when this latter is removed from the liquid filter, for instance, during a filter maintenance operation.

To this end, the invention concerns first a liquid retention member that is designed to receive an annular filter element and to be removably mounted with the annular filter element in the filter chamber of a liquid filter. The filter chamber is delimited by a filter housing having a peripheral wall, a bottom wall and by a removable filter cap that closes a main filter opening of the filter housing through which can be removed the liquid retention member.

The liquid retention member comprises an outer tubular wall, an inner tubular wall arranged in the outer tubular wall and an annular bottom wall that extends radially between the inner and the outer tubular walls. The outer tubular wall, the inner tubular wall and the annular bottom wall are globally centred on a same central axis that is substantially vertically oriented when the liquid retention member is mounted in the filter chamber of a liquid filter. The outer tubular wall, the inner tubular wall and the annular bottom wall form together an annular volume in which can be arranged the annular filter element. The annular bottom wall is liquid-tight. Furthermore, the outer tubular wall and the inner tubular wall are liquid-tight over a height, measured parallel to the central axis from the annular bottom wall, that is superior to 50%, preferably 75% of the height of the annular filter element for which the liquid retention member is designed.

During a filter maintenance operation, the use of the liquid retention member according to the invention limits splashing of the liquid outside the filter housing and outside the liquid retention member. Indeed, during a filter maintenance operation, when the filter element is removed with the liquid retention member from the filter housing, and due to the specific dimensions of the liquid retention member, the remaining liquid that can flow from the filter element is retained in the liquid retention member. Thanks to that, during a maintenance operation of the liquid filter and in particular during the removing of the filter element with the liquid retention member, liquid splashes are greatly limited provided that the operator maintains the liquid retention member containing the filter element and the filtering liquid in a substantial vertical position. Then, the filter element can be separated from the liquid retention member in a further step that is preferably performed when the filtering liquid is at a non-hazardous temperature and above a liquid collector that is away from the vehicle especially from its engine block and that allows collection of the filtering liquid. Consequently and thanks to the invention, the replacement of a clogged filter element is less dirty.

The invention also concerns a filter sub-assembly that is designed to be mounted in the filter chamber of a liquid filter. The filter chamber is delimited by a filter housing having a peripheral wall, a bottom wall and is also delimited by a removable filter cap that closes a main filter opening of the filter housing through which the filter sub-assembly can be removed..

The filter sub-assembly comprises :

- a liquid retention member such as previously described, an annular filter element located in the annular volume of the liquid retention member and comprising an annular filter medium.

The outer tubular wall and the inner tubular wall of the liquid retention member are liquid-tight over a height, measured parallel to the central axis and from the annular bottom wall of the liquid retention member, that is superior to 50%, preferably 75% of the filter element height. The filter sub-assembly is designed as a removable part of the liquid filter and can be removed from the filter housing through the main opening.

During a filter maintenance operation, the use of the filter sub-assembly according to the invention limits splashing of the liquid outside the filter housing. Indeed, during a filter maintenance operation, when the filter sub-assembly is removed from the filter housing, and due to the specific dimensions of the liquid retention member, the remaining liquid that can flow from the filter element is retained in the liquid retention member. In order to be replaced by a new one, the filter element can be separated from the liquid retention member in a further step that is preferably performed when the filtering liquid is at a non- hazardous temperature and above a liquid collector that is away from the vehicle. Another option is to replace the whole filter sub-assembly.

Consequently and thanks to the invention, the replacement of a clogged filter element or of a filter sub-assembly is less dirty. According to further aspects of the invention which are advantageous but not compulsory, such a filter sub-assembly may incorporate one or several of the following features :

- The annular filter element comprises at least one end-cap fixed at the axial end of the annular filter medium that is opposite to the annular bottom wall of the liquid retention member and the annular filter element is preferably in abutment via one of its axial ends against the annular bottom wall.

- The annular filter element is advantageously dismountable from filter subassembly.

- The annular filter element is attached in liquid-tight manner via one of its axial ends on the annular bottom wall.

- The axial end of the inner tubular wall that is opposite to the bottom wall and that extends in the filter element is axially opened such that the inner tubular wall forms a sub-assembly outlet of the filter sub-assembly.

- The filter sub-assembly can include a movable plug located between the inner tubular wall and a top end-cap of the filter element that is fixed at the axial end of the annular filter medium that is opposite to the annular bottom wall of the liquid retention member. The movable plug is movable between an open position to open said sub-assembly outlet when the filter sub-assembly is mounted in the filter housing and a closed position to close said sub-assembly outlet when the filter sub-assembly is removed from the filter housing. Thanks to this plug risks of liquid splashing outside the filter housing or outside the filter sub-assembly are much reduced during a filter maintenance operation where the filter element has to be removed from the filter housing in order, for instance, to be replaced by a new one.

- Preferably, the movable plug has a tubular portion that is coaxial and in sliding contact with the inner tubular wall. The tubular portion is open at its axial extremity that is on the side of the bottom wall of the liquid retention member such that the inside of the tubular portion of the movable plug is in liquid communication with said sub-assembly outlet and is closed at its opposite extremity. The tubular portion has at least one radial opening that is in liquid communication with the inside of the tubular portion of the movable plug. Said at least one radial opening is, in the open position of the movable plug, at least partially above the axial end of the inner tubular wall to put into liquid communication liquid flowing through the filter element with the sub-assembly outlet. Said at least one radial opening is, in the closed position of the movable plug, below the axial end of the inner tubular wall, such that said at least one radial opening is in front of the tubular surface of the inner tubular wall which closes said radial opening and therefore said subassembly outlet. The positions "partially above" and "below" of the radial opening determined with respect to the axial end of the inner tubular wall are determined when the sub-assembly is in a substantial vertical position, that is to say when the central axis of the liquid retention member is in an substantial vertical orientation and when the annular bottom wall of the filter sub-assembly is in the lowest position compared to the other parts of the filter sub-assembly.

- The movable plug comprises a zone of abutment which contacts the axial end of the inner tubular wall in the closed position of the movable plug and, when the filter-sub-assembly is inserted in the filter housing, the movable plug is urged towards its open position by an axial extension of the filter housing. Preferably, the movable plug is urged towards its closed position by a compression spring or any other elastic mean arranged between the top end-cap of the annular filter element and the movable plug.

The invention further concerns a liquid filter which comprises - a filter housing having a peripheral wall, a bottom wall, and a main filter opening located at a top extremity of the filter housing, at least one liquid inlet opening and at least one liquid outlet opening,

- a removable filter cap removably fixed to the main filter opening and which delimits with the filter housing a filter chamber,

- a filter sub-assembly as previously described that is mounted in the filter chamber of the filter housing and that is removable from the filter housing through the main filter opening.

According to further aspects of the invention which are advantageous but not compulsory, such a liquid filter may incorporate one or several of the following features :

- Preferably, the filter sub-assembly and the removable filter cap include means of attachment of the filter sub-assembly on the removable filter cap. Means of attachment are arranged such that the filter sub-assembly can be removed by removing the removable filter cap from the filter housing.

- In an advantageous embodiment, the means of attachment are flexible legs formed in the removable filter cap. In this case, each flexible leg is preferably configured to engage in a groove of the filter sub-assembly and to cooperate with an axial abutment formed in the groove to pull the filter sub-assembly when the removable filter cap is removed from the filter housing.

- According to another aspect of the invention, the axial end of the inner tubular wall of the filter sub-assembly that is opposite to the bottom wall and that extends in the filter element is opened such that the inner tubular wall forms a sub-assembly outlet of the filter sub-assembly. The liquid filter preferably includes a movable plug for closing said sub-assembly outlet when the sub-assembly is removed from the filter housing. The movable plug is attached to, preferably integral with, the removable filter cap. Thanks to this plug risks of liquid splashing outside the filter housing or outside the filter sub-assembly are much reduced during a filter maintenance operation where, for instance, the filter element has to be removed from the filter housing.

- The means of attachment are preferably designed with an axial clearance such that the filter sub-assembly can axially move between at least two axial positions with respect to the removable filter cap. More specifically, between :

• a first axial position, corresponding to an open position of said subassembly outlet when the removable filter cap is fasten onto the filter housing and where the filter sub-assembly is close to the removable filter cap, and • a second axial position, corresponding to a closed position of said subassembly outlet when the removable filter cap is removed from the filter housing and where the filter sub-assembly is away from the removable filter cap, that is to say at an axial distance from the removable filter cap that is higher than in the first axial position.

- The annular filter element comprises a top end-cap fixed at the axial end of the annular filter medium that is opposite to the annular bottom wall of the liquid retention member. The inner tubular wall and said top end-cap define between them at least one radial opening of the filter sub-assembly that is, in operating conditions of the liquid filter, in liquid communication with the sub-assembly outlet to allow the liquid to flow out from the liquid filter sub-assembly through the subassembly outlet. The movable plug has a tubular shape opened at is axial free end and which extends from the removable filter cap, through said top end-cap and up to the inner tubular wall when the filter sub-assembly is attached to the removable filter cap. Said tubular shape comprises a liquid-tight tubular portion and a portion which is provided with at least one radial opening. In the first axial position of the filter sub-assembly, said at least one radial opening of the filter sub-assembly is substantially aligned with said at least one radial opening of the tubular shape such that liquid may flow out through the sub-assembly outlet when the removable filer cap closes the filter chamber. In the second axial position of the filter subassembly, said at least one radial opening of the filter sub-assembly is substantially in front of the liquid-tight tubular portion that plugs, at least partially, said radial opening of the filter sub-assembly such that the liquid is limited from flowing out through the sub-assembly outlet when the removable filter cap is removed with the filter sub-assembly from the filter housing.

- In the second axial position of the filter sub-assembly, said at least one radial opening of the filter sub-assembly is in front of the liquid-tight tubular portion of the movable plug that plugs totally said radial opening of the filter sub-assembly (11) such that the liquid is prevented from flowing out through the sub-assembly outlet when the removable filer cap is removed with the filter sub-assembly from the filter housing.

- The tubular shape is in sliding contact with the inner or outer surface of the inner tubular wall when the filter sub-assembly is attached to the removable filter cap.

- The tubular shape of the plug extends from the removable filter cap up to the inside or outside surface of the inner tubular wall when the filter sub-assembly is attached to the removable filter cap. - In a variant, the means of attachment are flexible legs extending radially from the inner tubular wall to cooperate with corresponding grooves formed on the movable plug.

- In another variant, the means of attachment are flexible legs extending radially from the movable plug to cooperate with corresponding grooves formed in the inner tubular wall.

- Liquid filter includes wiper rings (arranged to remove liquid from an external surface of the outer wall of the liquid retention member when it is removed.

The invention also concerns a vehicle, equipped with a liquid filter as previously

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be explained in correspondence with the annexed figures, and as an illustrative example, without restricting the object of the invention. In the annexed figures:

- figure 1 is a side view of a truck comprising a non-represented liquid filter according to the invention,

- figure 2 is a longitudinal section of an liquid filter according to a first embodiment of the invention,

- figure 3 is a longitudinal section of a filter filter sub-assembly designed to be mounted the filter housing of figure 2,

- figure 4 is a longitudinal section, analog to that of figure 2 and at lower scale, of an liquid filter according to a second embodiment of the invention,

- figure 5 is a longitudinal section analog to figure 4, in which the filter sub-assembly of figure 4 is removed,

- figures 6 and 7 are sections analog to figures 4 and 5 of an liquid filter according to a third embodiment of the invention,

- figures 8 and 9 are sections analog to figures 6 and 7 of an liquid filter according to a fourth embodiment of the invention, and

- figure 10 is a section analog to figure 2, representing an liquid filter according to a fifth embodiment of the invention.

DETAILED DESCRIPTION

Figure 1 represents a truck 2 comprising a traction unit, or lorry 6. The lorry 6 tows a trailer 4 and comprises at least two pairs of wheels 10. The trailer 4 includes two pairs of rear wheels 10. The truck 2 includes an engine compartment 8 in which is arranged at least one liquid filter , this liquid filter 1 being not visible on figure 1.

The liquid filter 1 can be, for instance, adapted to clean fuel or oil circulating in the engine of the truck 1 and therefore the liquid filter represented on figures 2 to 10 can be a fuel or an oil filter. As shown on figure 2, the liquid filter 1 includes a filter housing 12. The filter housing 12 includes a peripheral wall 120 which defines a filter chamber 012 wherein is arranged a filter sub-assembly 11. The filter housing 12 includes an annular bottom wall 122 that extends inwardly from the peripheral wall 120. The filter housing 12 may include an inner tubular wall 124 that is disposed coaxially inside the outer tubular wall 120. In this case, annular bottom wall 122 connects radially the outer tubular wall 120 and the inner tubular wall 124.

The filter housing 12 has a main filter opening 125 arranged to open the filter chamber 012 at a top extremity of the filter housing 12.

In operating conditions, a removable filter cap 18 is removably fixed to the main filter opening 125 to close the filter chamber 012, and to prevent or at least to limit liquid from splashing outside of the filter housing 12. This removable filter cap 8 is removable from the filter housing 12 so as to allow replacing inside components of the liquid filter 1. In the example of figure 2, the removable filter cap 18 is screwed onto the filter housing 2 but it may be fixed by any other appropriate means such as by a bayonet fixation type.

The filter housing 12 may include an intermediate inner tube 126, that is disposed coaxially between walls 120 and 24 and that delimits with the outer wall 20 an annular liquid inlet passage V12. Indeed, the annular bottom wall 122 is provided with at least one liquid inlet opening 0122 that face the annular liquid inlet passage V12. On figures 2 and 4 to 0, two liquid inlet openings 0122 are represented. The filter housing 12 includes in the center of the annular bottom wall 122 a liquid outlet opening 0124 that is formed by the inner tubular wall 24 when this latter is provided.

The liquid filter 1 includes an annular filter element 16 having annular shape centered on a central axis Z 2. The annular filter element 16 is arranged inside the filter chamber 012. The annular filter element 16 comprises a filter medium 161 that can be made of a sheet of cellulose or synthetic paper that may be impregnated with a resin and that is pleated in such a manner that the filter medium 161 is ring shaped. The annular filter element 16 may further comprises inside the tube shaped filter medium 161 a tubular grid 15 which extends along the central axis Z12 and which radially supports the filter medium 161. The annular filter element 16 comprises at least one top end cap 150 which is generally liquid-tight and which is sealed to the axial ends of the ring shaped filter medium 161. End cap 150 may have a disc shape, such as represented on figures 2 to 5, or an annular shape, such as represented on figures 6 to 10, and can be bounded on the axial end of the ring shaped filter medium 161. End cap 150 can also be clipped or bounded on the axial extremities of the tubular grid 15.

The annular filter element 16 is fixed or detachable part of a filter sub-assembly 11 which includes a liquid retention member 14, comprising an outer tubular wall 140 that is preferably centred on the axis Z12 and an inner tubular wall 142 arranged coaxially inside the outer wall 140. The outer tubular wall 140 has an external surface S140. The liquid retention member 14 also includes an annular bottom wall 144 that connects radially the inner and outer tubular walls 140 and 142. The annular bottom wall 144 is also preferably centred on the axis Z12. The annular bottom wall 144 is liquid-tight. The outer and inner walls 140 and 142 delimit between them an annular volume V14 wherein is arranged the annular filter element 16. The annular filter element 16 is arranged in the annular volume V14 such that the filter medium 161 does not contact with outer and inner walls 140 and 142. In other words, radial clearances are kept between the filter medium 16 and outer and inner walls 140 and 142 to allow a better liquid circulation and a better distribution of the liquid flowing along the annular filer element 16.

The inner tubular wall 142 extends inside the filter element 16 and is opened at its top extremity 143 extending inside the filter element 16 to form a sub-assembly outlet 19 of the filter sub-assembly 11. When the filter sub-assembly 11 is mounted in the filter housing 12, the sub-assembly outlet 19 is in liquid communication with the liquid outlet opening 0124 of the filter housing 2.

If the liquid filter is not provided with the intermediate inner tube 126, the annular liquid inlet passage V12 is delimited between the peripheral wall 120 and the outer tubular wall 140 of the liquid retention member 14. In the first embodiment of figure 2, the lower end cap of the annular filter element 16, that is opposite to the filter main opening 125, is formed by the annular bottom wall 144. In other words, the lower axial end of the ring shaped filter medium 162 is attached, for instance glued on the annular bottom wall 144 or fused with the annular bottom wall 144 in liquid-tight manner. In a variant, such as represented on figure 10, the annular filter element 16 can also comprises a lower end cap 150' that is distinct from the annular bottom wall 144. In this variant, the lower end cap 150' of the annular filter element 16 is in sealing contact with the annular bottom wall 144.

If the inner tube 126 is provided, a lip seal 128 can be arranged in a peripheral groove 129 of the inner tube 126. This lip seal 128 is adapted to scrape down liquid present on the external surface S 140 of the outer wall 140 when removing the filter sub- assembly 1 . Therefore, the lip seal forms wiper ring, arranged to remove liquid from the external surface S140 of the outer wall 140. In the embodiments corresponding to those of figures 2, 3, 4 and 5, the top end cap 150, that is to say the end cap 150 that is on the side of the main filter opening 125, is disc shaped and, at least during operational state of the filter, is axially contacted by the removable filter cap 18, to axially urge the annular filter element 16 towards the bottom wall 144 of the liquid retention member 16 and the liquid retention member 14 against the the bottom wall 122 of the filter housing 1. Thanks to this arrangement the annular filter element 16 and the liquid retention member 14 are prevented from moving.

For filtration maintenance the filter sub-assembly 11 is entirely removable from the liquid filter 1. Depending whether the filter element 16 if fixed on the liquid retention member 14 or is detachable from it, the spare part that can be replaced by another for filtration maintenance can be the whole filter sub-assembly 11 or the filter element 16 alone.

Here-below one explains the liquid flow circulation in the liquid filter 1 with regards to figure 2.

Firstly, unfiltered, or dirty liquid enters the filter chamber by the openings 0122, as shown by arrows F1 on figure 2. Liquid flows then upwards in the annular liquid inlet V12 delimited between the outer wall 120 and the internal tube 126 of the filter housing 12 or, if this latter is not provided, between the outer wall 120 and the outer tubular wall 140. Afterwards, unfiltered liquid is spilled in the annular volume V14 portion that is radially outside from the filter medium 161 , as shown by the arrows F2. Liquid flows into the liquid retention member 14 and flows radially through the filter medium 161 , as shown by the arrows F3. By flowing through the filter medium 161 , metallic particles and other undesirable particles are trapped by the filter medium 161 and therefore removed from liquid in circulation. Finally, downstream from the filter medium 161 filtered liquid overtops the inner tubular wall 142 and flows outside the filter chamber 012 through the subassembly outlet 19 in a downward direction such as represented by arrows F4.

When the filter medium 16 becomes clogged by particles and impurities, it needs to be replaced, the operator removes the filter removable cap 18 from the filter housing 12 and then removes the filter sub-assembly 11 that comprises the liquid retention member 14 and the filter element 16. Indeed, the liquid retention member 14 and the filter element 1 are designed to be removed together from the filter housing via the filter main opening 125.

In the first embodiment represented on figure 2, the filter element 16 is attached via the annular bottom wall 122 to the the liquid retention member 14. In this case, the whole filter sub-assembly 11 constitutes a spare part that is replaced by another during a maintenance operation of the liquid filter 1. In a different manner, such as represented on figure 10, the filter element 16 is detachable from the liquid retention member 14. In this latter case and during maintenance operation, the liquid retention member 14 and the filter element 11 are removed together, and then the filter element 16 can be detached from the liquid retention member to be replaced by a new one and the liquid retention member 14 is re-used with the new filter element.

The lip seal 128 wipes liquid from the external surface S140 of the outer wall 140 of the liquid retention member 14, so as to avoid liquid dripping along to external surface of the outer wall 140.

When the filter sub-assembly 11 is removed from the liquid filter 1 , liquid accumulated in the annular volume V14 does not splash, or in a limited manner, around or below the filter element 11 because the inner wall 142, the outer wall 140 and the bottom wall 144 are liquid-tight. More specifically, the outer tubular wall 140 and the inner tubular wall 142 are liquid-tight over heights h140, h142, measured parallel to the central axis Z12 from the annular bottom wall 144, that are superior to 50%, preferably 75% of the filter element height h140. In other words, liquid can't flow through these walls 140, 142, 144 over the heights h140, h142. Due to these dimensions of the liquid retention member 14, when sub-assembly is removed from the filter housing 12 for a maintenance operation of the liquid filter, main volume of the liquid that can flow from the filter element 16 is retained in the liquid retention member 14. Thanks to that, during a maintenance operation of the liquid filter and in particular during the removing operation of the filter sub-assembly 1 , liquid splashes are greatly limited provided that the operator maintains in a substantial vertical position the sub-assembly filter 11. Consequently, the replacement of a clogged filter element 16 or of the sub-assembly comprising the clogged filter element 16 can be a very clean operation. For instance, walls 140, 142, 144 of the liquid retention member 14 can be made of plastic material, for instance a polyamide plastic material such as PA 66 that is liquid tight. A liquid impervious material can also be used.

On figures 4 to 10, a second to fifth embodiments of a liquid filter 1 are represented. Here-below are mentioned only the differences with the first embodiment represented on figures 2 and 3. Moreover, the components of the liquid filter of the second to fifth embodiments that are analog or identical to that of the first embodiment keep their numerical references while different or additional components have other numerical references. For the sake of clarity, a grid similar to grid 15 of the first embodiment can be used in the second to fifth embodiment, but it is not represented on figures 3 to 10. In the second embodiment represented on figures 4 and 5, liquid circulation is the same as the liquid filter of figures 2 and 3. As shown on figures 4 and 5, the liquid retention member 14 is attached to the removable filter cap 18. Indeed, the removable filter cap 18 includes several flexible legs 180, each configured to be engaged in an annular groove 155 or in an annular section groove formed on the top side of the filter sub-assembly 11. Preferably and such as represented on figures 2, 4, 5, 6, 7 the annular groove 155 or the annular section grooves also form inlet of the filter sub-assembly 11 in order to allow the liquid to access to the annular volume V14. Therefore, when removing the removable filter cap 18 from the filter housing 12, the filter sub-assembly 11 is pulled up since the legs 180 come into abutment against at least one annular bead 188 formed on the top end cap 15 and/or on the inner surface of the outer wall 140 and at the top extremity of the outer wall 140.

The filter sub-assembly 11 of figures 4 and 5 also includes a sealing plug 20. This sealing plug 20 includes a tubular portion centred on axis Z12. The tubular portion has a free end 202 at its lower side and a liquid-tight top crown 200 at its upper side. In operating conditions, the lower end 202 contacts a zone of abutment formed by the top annular surface 1241 of the inner wall 124, such that the non-pervious top crown 200 of the sealing plug 20 is pushed away from the annular top extremity 143 of the inner tubular wall 142 towards the top end cap 150 of the annular filter element 16 . According to a design variant, in operating conditions, the non-pervious top crown 200 of the sealing plug 20 can also contact the top end cap 150 of the annular filter element 16. The tubular portion of the sealing plug 20 delimits radial openings O20, through which liquid may flow, in operating conditions, to access the inside volume of the inner tubular wall 142 forming the sub-assembly outlet 19.

The sealing plug 20 forms a mean of closing the sub-assembly outlet 19 when the sub-assembly filter 1 is removed from the filter housing 12. Indeed, when the removable filter cap 18 is removed from the housing 12, as represented by arrows F5 on figure 5, the removable filter cap 18 pulls the liquid retention member 14 up, such that the tubular portion of the sealing plug 200 slides by gravity into the inner tubular wall 142 that closes the openings O20. Furthermore, the annular top extremity 143 of the inner tubular wall 142 contacts the top crown 200 of the sealing plug 20. The crown 200 can also be used to close the annular top extremity 143 of the inner wall 142. Therefore, liquid can't penetrate the inside of the inner tubular wall 142 when the filter sub-assembly 11 is removed. In an improvement, the sealing plug 200 can be urged towards the closing position by a compression spring (not represented) or any other elastic element arranged for instance, between the sealing plug 200 and the top end-cap 50.

On figures 6 and 7 is represented a third embodiment of a liquid filter 1. This liquid filter 1 is specific in that the the inner wall 124 arranged coaxially within the outer wall 120 has a lower height compared to the heights of the inner walls 124 of the embodiments represented on figures 2, 4 and 5. A non-previous top end cap 151 , having an annular shape is disposed at the upper extremity of the ring shaped filter medium 161. This top end cap 151 is centred on axis Z12.

The inner tubular wall 142 and the annular top end-cap 151 define between them at least one radial opening 0142 in the liquid filter sub-assembly 11 to allow, in operating conditions, the liquid to flow out from the liquid filter sub-assembly 11 through the subassembly outlet 19.

This liquid filter 1 of figure 6 and 7 also has the particularity of including means 182 for closing the sub-assembly outlet 19 when removing it from the housing 12. These means 182 are attached or preferably integral with the housing cap 18. The means are mainly formed by tubular portion 182 that is centred on axis Z12 and that is disposed at the center of the removable filter cap 18. The tubular portion 182 extends downwards through the annular end-cap 151 and includes radial openings 0182 on the upper portion and a non-pervious lower portion 182a. The lower portion 182a is configured to penetrate a liquid-tight portion of the inner tubular wall 142 of the liquid retention member 14 in operating conditions. When the removable filter cap 18 is fastened onto the filer housing, the tubular portion is engaged in the inner tubular wall 142 in such a manner that the radial opening 0142 is substantially aligned with the openings 0182 to create a liquid connection between the annular volume V14 and the sub-assembly outlet 19. Thanks to that, liquid accumulated in the liquid retention member 14 may flow, via said radial opening 0142. and the openings 0182 up to the sub-assembly outlet 19 and then flow out the filter chamber 012.

When removing the removable filter cap 18 with the filter sub-assembly 11 , the lower portion 182a of the tubular portion 182 slides along the internal surface of the inner tubular wall 142 and closes, such as represented on figure 7, the radial opening 0142 so that the liquid is prevented from flowing out from the liquid retention member 14 through the subassembly outlet 19. In parallel, as in the second embodiment of figures 4 and 5, the legs 180 move up inside the annular volume V14 defined between the filter element 16 and the outer tubular wall 140 to pull up the sub-assembly filter 11 when they come into abutment against annular beads 188 extending radially from the top end cap 15 and/or from the inner surface of the outer wall 140 and arranged at the top extremity of the outer wall 140.

In the example of figures 6 and 7, the liquid filter 1 also includes a peripheral seal 22 that is squeezed between the housing 12 and the cap 18 and a seal 24 that is squeezed between the bottom walls 122 and 144, respectively of the housing 12 and the liquid retention member 14. The liquid filter 1 also includes a seal 26 arranged between the inner walls 124 and 142, respectively of the filter housing 12 and the liquid retention member 14.

On figures 8 and 9 is represented a fourth embodiment of a liquid filter 1. This liquid filter 1 has the particularity of having a liquid retention member 14 that includes, on its inner tubular wall 142, prominent parts 142a. The prominent parts 142a are teeth oriented radially away from the axis Z12.

The removable filter cap 18 includes a tubular member 184 that extends downwards inside the inner wall 142 of the liquid retention member 14. This tubular member 184 is centred on axis Z12 and delimits upper radial openings 0184' and lower radial openings 0184. The upper openings 0184' are openings through which liquid flows to access the sub-assembly outlet 19 in operating conditions. The prominent parts 142a of the inner wall 142 penetrate each radially in lower openings 0184 so as to lift the liquid retention member 14 up when removing the housing cap 18. Indeed, when removing the housing cap 18, the lower edge of openings 0184 come into abutment with the prominent parts 142a and the liquid retention member 14 is raised by the cap 18. More precisely, the cap 18 is first lifted along a dead travel before the lower edges of openings 0184 contact the prominent parts 142a. Thanks to this dead travel, a liquid-tight tubular portion 184a of tube 184 projects upwards over the top edge of the liquid retention member 14.

Therefore, liquid has then to overtop the top edge of the liquid-tight tubular portion 184a to access the outlet 19 of the filter sub-assembly 11. Since the liquid-tight tubular portion 184a projects upwards over the top edge of the liquid retention member 14, a bigger volume of the filter element 16 formed by the filter medium 161 and the grid 15 is encompassed when removing the liquid filter sub-assembly 11. The tubular member 184 forms means for limiting liquid from overtopping the inner wall 142 of the liquid retention member 14 when removing the filter sub-assembly 11 from the filter housing 12. Described differently, the inner tubular wall 142 and the annular top end-cap 151 of the filter element 16 define between them at least one radial opening 0142 of the liquid filter sub-assembly 11 and, when the removable filter cap 18 is removed with the filter subassembly 11 from the filter housing 12, the liquid-tight tubular portion 184a plugs at least partially the radial opening 0142 such that the liquid is limited from flowing out through the sub-assembly outlet 9;

In order to be able to disengage the prominent parts 142a from radial lower openings 182a such that the filter sub-assembly can be dismounted from the removable filter cap 16, the prominent parts 142a are preferably flexible or the inner tubular wall 142 is radially deformable. To be radially deformable, the inner tubular wall is preferably made of a flexible material. In a variant of the embodiment of figures 8 and 9, lower openings 0184 could be replaced by longitudinal grooves which are not opened in a radial direction. In another variant prominent parts can be formed around the tubular member 184 and corresponding recess shapes can be formed in the inner tubular wall 142.

On figure 10 is represented a fifth embodiment of a liquid filter 1. This liquid filter 1 is analog to that of figures 8 and 9 but has the particularity of having wiper means M1. These wiper means M1 allow scraping liquid present on the internal surface S142 of the inner wall 142 and on the external surface S140 of the outer wall 140 when removing the filter element 11. The wiper means M1 include a seal 40 attached on the inner side of the outer wall 120 and a seal 42 attached on the outer side of the inner wall 124. The seals 40 and 42 are both centred on axis Z12 and have a triangular cross-section in a plane containing axis Z12. The seal 40 has an internal peripheral edge that is linear or quasi- linear and the seal 42 also has an outer peripheral edge that is linear or quasi-linear. With this arrangement, liquid does not drip either along the internal surface of the inner wall 142 nor along the external surface of the outer wall 140.

The liquid filter of figure 10 also differs from that represented on figures 8 and 9 in that it includes a removable cap having a tubular member 182 projecting inside the filter housing 12 and surrounding the inner tubular wall 142 of the liquid retention element 14 and in that the tubular member 182 is configured to close the sub-assembly outlet 19 of the filter sub-assembly 11 when removing it from the filter housing 12. The inner tubular wall 142 has outwardly oriented prominent parts 142a that are each engaged in radial openings 0182 of the tubular member 182. The tubular member 182 also delimits radial openings 0182' through which liquid flows to access the outlet 19 of the liquid filter element 1 in operating conditions. The openings 0182' are disposed above openings 0182.

When removing the housing cap, the lower edge of openings 0182 come into abutment with the prominent parts 142a and the liquid retention member 14 is raised by the removable filter cap 18. More precisely, the removable filter cap 18 is first lifted along a dead travel before the lower edges of openings 0182 contact the prominent parts 142a. Thanks to this dead travel, when the filter sub-assembly 11 is removed, a non-pervious tubular portion 182a that is disposed between openings 0182 and 0182' projects upwards over the top edge of the liquid retention member 14.. Therefore, when the filter sub-assembly 11 is removed with the removable filter cap 18, the tubular portion 182a closes at least partially radial opening 0142 formed between the inner tubular wall 142 and the top end cap 151. In a non-represented alternative embodiment, close to that of figures 8 to 10, the liquid retention member 14 includes only one prominent part 142a that is engaged in one opening of the tubular member 182 or 184.

It is to be understood that the present invention is not limited to the embodiments described above and illustrated in the drawings. Rather, the skilled person will recognize that many changes and modifications may be made within the scope of the appended claims.

Besides, the technical features of the different embodiments and alternative embodiments of the invention described here-above can be combined together to generate new embodiments of the invention.

Claims

1- A liquid retention member (14) that is designed to receive an annular filter element (16) and that is designed to be removably mounted with the annular filter element (16) in the filter chamber (012) of a liquid filter (1) wherein the filter chamber (012) is delimited by a filter housing (12) having a peripheral wall (120), a bottom wall (122) and by a removable filter cap (18) that closes a main filter opening (125) of the filter housing (12) through which can be removed the liquid retention member (14),

wherein :

- the liquid retention member (14) comprises an outer tubular wall ( 40), an inner tubular wall (142) arranged in the outer tubular wall (140) and an annular bottom wall (144) that extends radially between the inner and the outer tubular walls (142, 140),

- the outer tubular wall (140), the inner tubular wall (142) and the annular bottom wall (144) are globally centred on a same central axis (Z12), that is substantially vertically oriented when the liquid retention member (14) is mounted in the filter chamber (012), and the outer tubular wall (140), the inner tubular wall (142) and the annular bottom wall (144) form together an annular volume (V14) in which can be arranged the annular filter element (16),

- the annular bottom wall (144) is liquid-tight,

- the outer tubular wall (140) and the inner tubular wall (142) are liquid- tight over a height (h142), measured parallel to the central axis (Z12) from the annular bottom wall (144), that is superior to 50%, preferably 75% of the height (h140) of the annular filter element (16) for which the liquid retention member (11) is designed.

2- A filter sub-assembly (11) that is designed to be mounted in the filter chamber of a liquid filter (1), wherein the filter chamber is delimited by a filter housing (12) having a peripheral wall (120), a bottom wall (122) and by a removable filter cap (18) that closes a main filter opening (125) of the filter housing (12) through which the filter subassembly (11) can be removed,

wherein the filter sub-assembly (11) comprises :

a liquid retention member (14) according to claim 1 ,

- an annular filter element (16) located in the annular volume (V14) of the liquid retention member (14) and comprising an annular filter medium (161), wherein :

the outer tubular wall (140) and the inner tubular wall (142) are liquid-tight over a height (h142), measured parallel to the central axis (Z12) from the annular bottom wall (144), that is superior to 50%, preferably 75% of the height (h140) of the annular filter element (16),

the filter sub-assembly (11) is designed as a removable part of the liquid filter (1) and can be removed from the filter housing (12) through the main opening (125).

Filter sub-assembly (11) according to claim 2, characterized in that the annular filter element (16) comprises at least one end-cap (150, 151) fixed at the axial end of the annular filter medium (161) that is opposite to the annular bottom wall (144) of the liquid retention member (14) and in that the annular filter element ( 6), is in abutment via one of its axial ends against the annular bottom wall (144).

Filter sub-assembly (11) according to claim 2 or 3, characterized in that the annular filter element (16) is dismountable from the filter sub-assembly (11).

Filter sub-assembly (11) according to claim 2 or 3, characterized in that the annular filter element (16) is attached in liquid-tight manner via one of its axial ends on the annular bottom wall (144).

Filter sub-assembly (11) according to anyone of claims 2 to 5, characterized in that the axial end (143) of the inner tubular wall (142) that is opposite to the bottom wall (144) and that extends in the filter element (16) is axially opened such that the inner tubular wall (142) forms a sub-assembly outlet (19) of the filter sub-assembly (11).

Filter sub-assembly according to claim 6, characterized in that said filter sub-assembly (1 ) includes a movable plug (20) located between the inner tubular wall (142) and a top end-cap (150) of the filter element (16) that is fixed at the axial end of the annular filter medium (161) that is opposite to the annular bottom wall (144) of the liquid retention member (14), wherein the movable plug (20) is movable between an open position to open said sub-assembly outlet (19) when the filter sub-assembly (11) is mounted in the filter housing and a closed position to close said sub-assembly outlet (19) when the filter sub-assembly (11) is removed from the filter housing (12). 8- Filter sub-assembly according to claim 7, characterized in that the movable plug (20) has a tubular portion that is coaxial and in sliding contact with the inner tubular wall

(142) , the tubular portion being open at its axial extremity that is on the side of the bottom wall (144) such that the inside of the tubular portion of the movable plug (20) is in liquid communication with said sub-assembly outlet (19) and is closed at its opposite extremity, the tubular portion having at least one radial opening (O20) that is in liquid communication with the inside of the tubular portion of the movable plug (20) and that is, in the open position of the movable plug (20), at least partially above the axial end

(143) of the inner tubular wall (142) to put into liquid communication liquid flowing through the filter element (16) with the sub-assembly outlet (19) and that is, in the closed position of the movable plug (20), below the axial end (143) of the inner tubular wall (142), such that said at least one radial opening (O20) is in front of the tubular surface of the inner tubular wall (142) which closes said sub-assembly outlet (19).

9- Filter sub-assembly according to claim 8, characterized in that the movable plug (20) comprises a zone of abutment which contacts the axial end (143) of the inner tubular wall (142) in the closed position of the movable plug (20) and in that, when the filter- sub-assembly (11) is inserted in the filter housing (12), the movable plug (20) is urged towards its open position by an axial extension (124) of the filter housing (12).

10- Liquid filter (1), comprising :

- a filter housing (12) having a peripheral wall (120), a bottom wall (122), and a main filter opening (125) located at a top extremity of the filter housing (12), at least one liquid inlet opening (0122) and at least one liquid outlet opening (0124),

- a removable filter cap (18) removably fixed to the main filter opening (125) and which delimits with the filter housing (12) a filter chamber (012),

- a filter sub-assembly (11) according to anyone of claims 2 to 9, that is mounted in the filter chamber (012) of the filter housing (12) and that is removable from the filter housing ( 2) through the main filter opening (125).

11- Liquid filter according to claim 10, characterized in that the filter sub-assembly (11) and the removable filter cap (18) include means (180) of attachment of the filter subassembly (11) on the removable filter cap (18) which are arranged such that the filter sub-assembly can be removed by removing (F5) the removable filter cap (18) from the filter housing (12). 12- Liquid filter according to claim 11 , characterized in that the means of attachment are flexible legs (180) formed in the removable filter cap, each flexible leg being configured to engage in a groove of the filter sub-assembly (11) and to cooperate with an axial abutment formed in the groove to pull the filter sub-assembly (11) when the removable filter cap (18) is removed from the filter housing (12).

13- Liquid filter according to claim 11 or 12, characterized in that the axial end (143) of the inner tubular wall (142) of the filter sub-assembly (11) that is opposite to the bottom wall (144) and that extends in the filter element (16) is opened such that the inner tubular wall (142) forms a sub-assembly outlet (19) of the filter sub-assembly (11) and in that the liquid filter (1) includes a movable plug ( 182, 184) for closing said subassembly outlet (19) when the sub-assembly (11) is removed from the filter housing (12), wherein the movable plug (182, 184) is attached to, preferably integral with, the removable filter cap (18).

14- Liquid filter according to claim 13, characterized in that the means (180) of attachment are designed with an axial clearance such that the filter sub-assembly (11) can axially move between at least two axial positions with respect to the removable filter cap (18), a first axial position corresponding to an open position of said sub-assembly outlet (19) when the removable filter cap (18) is fasten onto the filter housing and where the filter sub-assembly (11) is close to the removable filter cap (18) and a second axial position corresponding to a closed position of said sub-assembly outlet (19) when the removable filter cap (18) is removed from the filter housing (12) and where the filter sub-assembly (11) is away from the removable filter cap (18).

15- Liquid filter according to claim 14, characterized in that the annular filter element (16) comprises a top end-cap (151) fixed at the axial end of the annular filter medium (161) that is opposite to the annular bottom wall (144) of the liquid retention member (14) , in that the inner tubular wall (142) and said top end-cap (151) define between them at least one radial opening (0142) of the filter sub-assembly (1 ) that is, in operating conditions of the liquid filter, in liquid communication with the sub-assembly outlet (19) to allow the liquid to flow out from the liquid filter sub-assembly (1 ) through the subassembly outlet (19), in that the movable plug (182, 184) has a tubular shape opened at is axial free end and which extends from the removable filter cap, through said top end-cap (151) and up to the inner tubular wall (142) when the filter sub-assembly (11) is attached to the removable filter cap (18), wherein said tubular shape comprises a liquid-tight tubular portion (182a, 184a) and a portion which is provided with at least one radial opening (0182', 0184') and in that, in the first axial position of the filter subassembly (11) said at least one radial opening (0142) of the filter sub-assembly (11) is substantially aligned with said at least one radial opening (0182', 0184') of the tubular shape such that liquid may flow out through the sub-assembly outlet (19) when the removable filer cap (18) closes the filter chamber (012) and, in the second axial position of the filter sub-assembly (11), said at least one radial opening (0142) of the filter sub-assembly (1 ) is substantially in front of the liquid-tight tubular portion (182a, 184a) that plugs, at least partially, said radial opening (0142) of the filter sub-assembly (11) such that the liquid is limited from flowing out through the sub-assembly outlet (19) when the removable filter cap (18) is removed with the filter sub-assembly (11) from the filter housing (12).

16- Liquid filter according to claim 15, characterized in that in the second axial position of the filter sub-assembly (11) said at least one radial opening (0142) of the filter subassembly (11) is in front of the liquid-tight tubular portion (182a) that plugs totally said radial opening (0142) of the filter sub-assembly (11) such that the liquid is prevented from flowing out through the sub-assembly outlet (19) when the removable filer cap (18) is removed with the filter sub-assembly (1 ) from the filter housing (12).

17- Liquid filter according to claim 15 or 16, characterized in that the tubular shape is in sliding contact with the inner or outer surface of the inner tubular wall (142) when the filter sub-assembly (11) is attached to the removable filter cap (18). 18- Liquid filter according to any one of claim 15 to 17, characterized in that the tubular shape of the movable plug (182, 184) extends from the removable filter cap up to the inside or outside surface of the inner tubular wall (142) when the filter sub-assembly ( 1) is attached to the removable filter cap (18). 19- Liquid filter according to anyone of claims 13 to 18, characterized in that the means of attachment are flexible legs (142a) extending radially from the inner tubular wall (142) to cooperate with corresponding grooves formed on the movable plug (182, 184).

20- Liquid filter according to anyone of claims 13 to 18, characterized in that the means of attachment are flexible legs extending radially from the movable plug (182, 184) to cooperate with corresponding grooves formed in the inner tubular wall (142). 21- Liquid filter according to anyone of claims 10 to 20, characterized in that Liquid filter includes wiper rings (128 ; M1) arranged to remove liquid from an external surface (S140) of the outer wall (140) of the liquid retention member (14) when it is removed.

22- Vehicle (2), characterized in that it includes an liquid filter (1) according to anyone of claims 10 to 21.