WO2024032973A1

WO2024032973A1 - Filter unit for filtering a fluid, circuit comprising the filter unit and packaging system comprising the circuit

Info

Publication number: WO2024032973A1
Application number: PCT/EP2023/068151
Authority: WO
Inventors: Giuseppe MURATORE; Luca PISCINA
Original assignee: Sidel Participations
Priority date: 2022-08-09
Filing date: 2023-07-03
Publication date: 2024-02-15

Abstract

A filter unit (1) for filtering a fluid comprising: an outer housing (2) comprising a first lateral wall ( 4) which delimits a receiving space (5); and a filter body ( 3) comprising a second lateral wall (6) provided with a plurality of through openings (7) configured to filter the fluid. The filter body (3) is housed in the receiving space (5) so as to define a gap (8) between the two lateral walls (4, 6). The filter body (3) has a proximal end (EP) and a distal end (ED), each of which has two sealing elements (9, 10). Both sealing elements (9, 10) of each end (EP, ED) are arranged in succession one behind the other and between the two lateral walls (4, 6) to define between them a respective control chamber (11, 12), which is separate and different from the gap (8) and is configured to detect fluid leaks from the gap (8) itself.

Description

TITLE: “FILTER UNIT FOR FILTERING A FLUID, CIRCUIT COMPRISING THE FILTER UNIT AND PACKAGING SYSTEM COMPRISING THE CIRCUIT” *** TECHNICAL FIELD The present invention relates to a filter unit for filtering a fluid, a circuit comprising the filter unit and a packaging system comprising the circuit. In particular, the present invention finds advantageous (but not exclusive) application for fluids comprising a liquid, such as, for example, a cleaning liquid, sterilization liquid or a liquid foodstuff product to be packaged. Preferably, the present invention finds advantageous (but not exclusive) application for sterile circuits. More preferably, the present invention finds advantageous (but not exclusive) application in packaging systems, in particular of the foodstuff industry. PRIOR ART Filters for filtering fluids (such as, for example, a liquid) are known which comprise a cylindrical filter body and an outer housing that is also cylindrical. The filter body is provided in correspondence of one of its cylindrical walls with a plurality of openings (holes) having a predetermined dimension and configured to filter (hold) particles of a dimension larger than the dimension of the openings. The filter body is inserted in the outer housing and is stably connected to it. The outer housing has a radial inlet in correspondence of a first end through which the fluid enters the filter unit, and an axial outlet, which is orthogonal to the radial inlet, in correspondence of the second end (which is opposite to the first end) through which the filtered fluid flows out of the filter unit. The filter body and the outer housing have a transverse dimension (in particular diameter) such that they define a gap between them in which the fluid is arranged before entering inside the through openings of the filter body to be filtered. In correspondence of the second end (namely, the outlet), the outer housing is conformed to define a radial abutment for the filter body. In particular, a sealing element (typically an O-ring) is arranged in proximity to the radial abutment, which is configured to perform the seal between the filter body and the outer housing. However, due to the conformation (required to ensure the aforesaid radial abutment) of the lateral wall of the filter body and of the lateral wall of the outer housing, axial stagnation points are created, that is, areas in which the fed fluid remains, without flowing out. These stagnation points are understandably undesired, as precisely part of the filtered fluid remains in this area resulting in the proliferation of bacteria. Therefore, the filter unit of a known type is not able to ensure the maintenance of the effective sterility of the filter unit itself, and consequently of the circuit and of the system in which it is mounted, set by the foodstuff industry. In addition, the stagnation areas have the drawback of also being difficult to clean and/or sterilize. In other words, the conformation of the stagnation areas do not allow dirt (dust, grease, or liquids) to be removed by cleaning, just as they do not allow bacteria and pathogens to be eradicated during sterilization. In fact, during the cleaning step and/or sterilization step, the cleaning solution and the superheated water are not able to easily reach these areas, thus making it difficult to remove the stagnated fluid. Filters of a known type also have the drawback that they do not allow the operator to check externally whether there is any fluid leakage in the abutment areas (for example, due to breakage of the sealing element), resulting in leakages of unfiltered fluid or external contaminants in the filtered fluid. Therefore, in the filter units of a known type, any leakage is not readily detectable. In this regard, in filters of a known type, the operator notices this occurrence, only at the time of routine maintenance, in which he/she disassembles the filter unit and separates the filter body from the outer housing. GB2222536A discloses a filter unit having a filtering body and an outer housing, which define between them a gap in which two sealing elements are positioned. DESCRIPTION OF THE INVENTION An object of the present invention is to provide a filter unit for filtering a fluid, a circuit comprising the filter unit, and a packaging system comprising the circuit which are free from the drawbacks of the state of the art and which are easy and inexpensive to produce. According to the present invention, a filter unit for filtering a fluid, a circuit comprising the filter unit, and a packaging system comprising the circuit are provided according to what is claimed in the appended claims. The claims describe preferred embodiments of the present invention forming an integral part of the present description. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will now be described with reference to the appended drawings, which illustrate non- limiting embodiments, wherein: - Figure 1 is a schematic and perspective view of a first embodiment of a filter unit in accordance with the present invention; - Figure 2 is a schematic and perspective view of the filter unit with a different orientation from Figure 1; - Figure 3 is a schematic and cross-sectional view of the filter unit of Figures 1 and 2 (with some parts removed for clarity); - Figure 4 is a schematic and perspective view of a second embodiment of the filter unit in accordance with the present invention; - Figure 5 is a schematic and perspective view of the filter unit of Figure 4, seen in a different orientation from Figure 4; - Figure 6 is a schematic and cross-sectional view of the filter unit of Figures 4 and 5 (with some parts removed for clarity); - Figure 7 is a schematic and longitudinal sectional view of the filter unit of Figure 1 or 4 (with some parts removed for clarity); and - Figures 8 and 9 are schematic and enlarged views of respective portions of Figure 7. PREFERRED EMBODIMENTS OF THE INVENTION In Figures 1-9, the number 1 denotes as a whole a filter unit for filtering a fluid. Preferably, but not limitedly, the fluid comprises a liquid. In the following discussion, reference will be made explicitly, without loss of generality, to a cleaning fluid and/or a sterilization fluid and/or a liquid or fluid product, (the so-called "pourable products"), to be packaged of a packaging system, in particular of the foodstuff industry. The pourable products can be, for example, carbonated liquids (such as sparkling water, non-alcoholic beverages and beer), non-carbonated liquids (such as still water, fruit juices, wine, tea, milk, flavoured water), emulsions, suspensions, high-viscosity liquids and beverages containing pulp and/or solid pieces. The filter unit 1 comprises an outer housing 2 and a filter body 3. The outer housing 2 comprises a lateral wall 4 that delimits a receiving space 5 (Figure 7). The filter body 3 comprises a lateral wall 6 provided with a plurality of through openings 7 configured to filter the fluid. In other words, the through openings 7 are configured to retain the particles (liquid, semisolid or solid) of the fluid passing through the filter body 3 that have a dimension greater than the dimension of the through openings 7. The through openings 7 are, preferably uniformly, distributed on the lateral wall 6. The through openings 7 have been illustrated schematically in Figures 1, 2, 4 and 5 and partially in Figure 7; whereas in Figures 3 and 6 they have been omitted for clarity. The filter body 3 is configured to be housed in the receiving space 5 of the outer housing 2, in such a way as to define a gap 8 between the lateral wall 4 of the outer housing 2 and the lateral wall 6 of the filter body 3. The filter body 3 has a proximal end EP and a distal end ED, which is opposite to the proximal end EP. A longitudinal axis X of the filter unit 1 extends longitudinally between the proximal end EP and the distal end ED. Each end EP and ED has a respective first sealing element 9 and a respective second sealing element 10 (in one non-limiting example they are O-rings). Both the sealing elements 9 and 10 of each end EP and ED are arranged in succession one behind the other and between the two lateral walls 4 and 6, so as to define a respective control chamber 11 or 12 between them, which is separate and different from the gap 8. Each control chamber 11 or 12 is configured to detect fluid leaks from the gap 8 itself. Each sealing element 9 or 10 of each end EP and ED is housed in a respective seat 13 (namely, throat) that is suitably conformed and obtained in the filter body 3. In particular, each seat 13 is obtained externally in the filter body 3, in particular in the area of the lateral wall 6 without the through openings 7. According to what is illustrated in the attached figures, the first sealing element 9A and the second sealing element 10A (Figures 7 and 9) are arranged in correspondence of the proximal end EP of the filter body 3, which define the control chamber 11. The control chamber 11 is delimited axially by the sealing elements 9A and 10A, and laterally (in particular radially) by the lateral walls 4 and 6. The sealing elements 9A and 10A are configured to perform a lateral (in particular radial) seal between the two lateral walls 4 and 6. In particular, the sealing elements 9A and 10A housed in the respective seats 13 are configured to be compressed (namely, squeezed) between the lateral walls 4 and 6 so as to make the seal. The first sealing element 9A is configured to prevent the fluid received in the gap 8 from leaking (passing) into the control chamber 11. The second sealing element 10A is, instead, configured to prevent external contaminants (which may be, for example, fluids and/or solids and/or dust) from entering the control chamber 11 from the outside. Therefore, the sealing element 10A ensures the sterility of the control chamber 11 and therefore of the gap 8. Similarly, the first sealing element 9B and the second sealing element 10B (Figures 7 and 8) are arranged in correspondence of the distal end ED of the filter body 3, which define the control chamber 12. The axial extension of the control chamber 12 is delimited by the sealing elements 9B and 10B, and laterally by the lateral walls 4 and 6. The sealing element 9B is configured to perform a lateral (in particular radial) seal between the two lateral walls 4 and 6; whereas, the sealing element 10B is configured to perform an axial seal. In this regard, please refer to Figures 7 and 8, which illustrate how the sealing element 10B is interposed between the end ED of the filter body 3 and a shoulder 14 of the lateral wall 4 of the outer housing 2, against which the distal end ED of the filter body 3 (and also the sealing element 10B) abuts, effectively compressing the sealing element 10B. In other words, the sealing elements 9B and 10B housed in the respective seats 13 are configured to be compressed (namely, squeezed) between the lateral walls 4 and 6 so as to perform the sealing. Specifically, the sealing element 9B is configured to prevent the fluid received in gap 8 from leaking into control chamber 12; whereas the sealing element 10B is configured to prevent the fluid received within the filter body 3 from leaking (passing) into control chamber 12. Advantageously, but not limitedly, as illustrated in Figures 7 and 9, the sealing elements 9A and 10A are arranged at the same distance from the axis X (namely, they are coradial). Advantageously, but not limitedly, as illustrated in Figures 7 and 8, the sealing elements 9B and 10B are arranged at different distances from the axis X (namely, they are not coradial). In particular, the sealing element 9B is arranged at a greater distance from the axis X than the sealing element 10B. Furthermore, the seat 13 of the sealing element 10B is obtained in the portion of the lateral wall 6 facing the shoulder 14 of the outer housing 2. Preferably, but not limitedly, as illustrated in the attached figures, the outer housing 2 and the filter body 3 each have a hollow cylindrical shape (i.e., they have a tubular shape) and are both arranged coaxial to the axis X which extends longitudinally between the proximal end EP and the distal end ED. Therefore, the gap 8 and each control chamber 11 or 12 have an annular shape and are coaxial to the axis X. The gap 8 is arranged axially between the two control chambers 11 and 12. Advantageously, but not limitedly, the lateral wall 4 of the outer housing 2 has at least one respective control opening 15 in correspondence of each control chamber 11 and 12 that is through and is configured to allow inspection of the respective control chamber 11 or 12. The control opening 15 places the respective control chamber 11 or 12 in communication with the environment outside the filter unit 1. Each opening 15 defines a respective spyhole so that a user can notice the presence of fluid that has entered the respective control chamber 11 or 12. In the case of leakage (passage) of fluid into the control chamber 11 or 12, this leakage is easily detected through the control opening 15, through which the outflow of fluid from the control chamber 11 or 12, or the presence of fluid in the control chamber 11 or 12, can be detected or inspected. Preferably, but not limitedly, several through openings 15 are provided for each control chamber 11 or 12, which may be preferably arranged equidistant from each other. In particular, in the embodiments shown in the attached figures, four through openings 15 arranged at 90° relative to each other around the axis X are provided. Advantageously, but not limitedly, each control aperture 15 extends radially relative to the axis X. According to what is illustrated in the attached non- limiting figures, the proximal end EP is closed by a closing wall 16 that is transverse, in particular orthogonal, to the lateral wall 6. Therefore, to allow the fluid to enter or exit (depending on the direction of feed thereof, as will be described in the following), the filter unit 1 comprises a passage mouth 30. The passage mouth 30 is provided with an axis Y that is transverse, in particular orthogonal, relative to the axis X. The passage mouth 30 projects (externally) from the lateral wall 4 of the outer housing 2. The passage mouth 30 of the filtering unit 1 arranged in this way allows the direction of fluid travel to vary from an axial direction to a radial direction, or vice versa (depending on the direction of feed). In particular, the filter unit 1 is configured to feed fluid with: a) a first direction in which: the unfiltered fluid enters (in particular radially) the outer housing 2 (namely, the gap 8) in correspondence of the passage mouth 30, then passes through the through openings 7 of the filter body 3 in order to be filtered, and finally exits coaxially to the axis X in correspondence of the distal end ED (namely, axially); or b) a second direction of travel (opposite to the first direction of travel) in which: the unfiltered fluid enters (in particular axially) in correspondence of the distal end ED into the filter body 3, passes through the through openings 7 of the filter body 3 in order to be filtered towards the gap 8, and lastly flows out of the passage mouth 30 transversely, in particular orthogonally, to the axis X (namely, radially). Advantageously, but not limitedly, the axis X and axis Y can be incident (namely, intersecting, as illustrated in Figures 1-3) or they can be skewed (namely, not intersecting, as illustrated in Figures 4-6). Advantageously, but not limitedly, by arranging the two axes X and Y askew, it is possible to obtain at least one portion of an inner surface 17 of the passage mouth 30 so that it is arranged tangentially to an inner surface 18 of the outer housing 2 (Figures 4-6). Advantageously, but not limitedly, the outer housing 2 described above has a first terminal portion A and a second terminal portion B, each of which is configured to cooperate with the respective sealing elements 9 and 10 of the respective end EP or ED of the filter body 3, and an intermediate portion C which is interposed between the two terminal portions A and B. The three portions A, B and C are arranged in succession along the axis X. In particular, the first terminal portion A cooperates with the sealing elements 9A and 10A that are arranged in correspondence of the proximal end EP of the filter body 3, and the second terminal portion B cooperates with the sealing elements 9B and 10B that are arranged in correspondence of the distal end ED of the filter body 3. The passage mouth 30 projects from the intermediate portion C. In particular, the passage mouth 30 projects from the intermediate portion C in proximity to the first terminal portion A. Advantageously, but not limitedly, the two terminal portions A and B and the intermediate portion C are made without solution of continuity (that is, they are made of a single piece). According to a possible non-limiting alternative, the two terminal portions A and B are made with a solution of continuity and are connected, in particular welded, with the intermediate portion C. Advantageously, the terminal portion B has a transverse dimension (in particular inner diameter) downstream of the second sealing element 10B, which is substantially equal to the transverse dimension (in particular inner diameter) of the filter body 3. In other words, the inner surface 19 of the second terminal portion B downstream of the second sealing element 10B is coradial to the inner surface 20 of the filter body 3 (Figures 7 and 8). Advantageously, but not limitedly, the filter body has in correspondence of its proximal end EP a handle 21 for inserting the filter body 3 inside the outer housing 2, or for extracting the filter body 3 from inside the outer housing 2. Advantageously, but not limitedly, the filter body 3 is held in position in the outer housing 2 by a locking element 22 that is arranged in correspondence of the terminal portion A. The locking element 22 is configured to lock the filter body 3 relative to the outer housing 2, in particular by a mechanical contact connection between the locking element 22 and the outer housing 2. This connection can be threaded. Preferably, the locking element 22 comprises a ring nut. Advantageously, but not limitedly, the filter unit 1 is used while keeping the axis X in a vertical orientation. Alternatively, the filter unit 1 can be used by keeping the axis X tilted relative to the vertical or by keeping it in a horizontal orientation. Advantageously, the filter unit 1 can be used by arranging the passage mouth 30 in an orientation defined by the installation requirement by simply rotating the filter unit 1 around the axis X so as to allow a feed from the right or left relative to the axis X itself. In use, the filter body 3 (provided with the sealing elements 9 and 10) is inserted in the receiving space 5 of the outer housing 2. The filter body 3 is introduced until its distal end ED abuts against the shoulder 14. After which, the outer housing 2 and the filter body 3 are locked by the locking element 22 which prevents relative movement between them. According to an additional aspect of the present invention, a circuit is provided for feeding fluid and comprises feeding ducts (not illustrated) and the previously described filter unit 1. The fluid fed from the feed circuit may comprise, for example (non-exhaustive and non-limiting list): a sterilization fluid and/or a cleaning fluid and/or a liquid product to be packaged, such as, for example, a pourable liquid foodstuff product. According to a further aspect of the present invention, a packaging system is provided comprising the circuit and therefore the filter unit 1. By way of non-limiting example, the packaging system may comprise a forming machine to form containers starting from preforms, and/or a filling machine configured to fill containers with a pourable product, a labelling machine configured to label the containers, and/or a capping machine configured to cap containers, and/or a sterilizing machine to sterilize caps. The containers may be bottles or cans, for example. Advantageously, but not limitedly, the packaging system may comprise cleaning and/or sterilization machines configured to perform cleaning and/or sterilization of at least a part of a machine of the packaging system. The circuit may be part of a cleaning and/or sterilization machine. This part of a machine of the packaging system may be a filling circuit that supplies the pourable product or an environment in which the filling is performed. The embodiments described herein can be combined with one another without departing from the scope of the present invention. The filtering unit 1 as well as the circuit and/or the packaging system described above have several advantages. Firstly, the filtering unit 1 ensures that the sterility standards set for the respective industry, for example foodstuff, are maintained. In particular, the dual presence of the sealing elements 9 and 10 ensures that the sterility of the gap 8 and therefore of the fluid that passes through the gap 8 itself is safeguarded. In fact, to lose the sterility of the gap 8 both the sealing elements 9 and 10 of at least one end EP or ED would have to malfunction (for example, break). Secondly, thanks to the control chamber each through opening 15 allows an operator to easily recognize leakages or outflows of fluid caused by any malfunction (such as, for example, breakage) of at least one of the sealing elements, promptly signalling to the operator also in proximity of which of the control chambers 11 and/or 12 the operator needs to intervene with maintenance (for example, by replacing the sealing element 9 and/or 10). In this regard, the breakage of at least one of the sealing elements 9A, 9B and 10B can be signalled by the outflow of fluid from the control opening 15 of the respective control chamber 11 and/or 12, or it can be detected by inspecting the chamber 11 or the chamber 12 by means of the opening 15; whereas, breakage of only the element 10A still allows the sterility of the gap 8 (and therefore of the fluid fed through the filter unit 1) to be maintained thanks to the action of the sealing element 9A. Each control chamber 11 or 12 can store and/or collect the fluid resulting from a leakage or spillage from the gap 8. As for the control chamber 12, the first sealing element 9B ensures that the fluid that has entered the chamber 12 due to leakage or breakage of the second sealing element 10B remains confined in the chamber 12 so that an operator can recognize the presence of this fluid by means of the opening 15 in communication with the chamber 12. As for the control chamber 12, the second sealing element 10B ensures that the fluid that has entered the chamber 12 due to leakage or breakage of the first sealing element 9B remains confined in the chamber 12, so that an operator can recognize the presence of this fluid by means of the opening 15 in communication with the chamber 12. As for control chamber 11, the second sealing element 10A ensures that the fluid that has entered the chamber 11 due to leakage or breakage of the first sealing element 9A remains confined in the chamber 11, so that an operator can recognize the presence of this fluid by means of the opening 15 in communication with the chamber 11. In this way, greater simplicity and/or safety is achieved during detection of any leakages and/or damage and/or breakages that could affect the cleanliness and/or sterility of the filter unit 1, or the efficiency of the same unit 1. Therefore, a filter unit is made available that allows a more effective monitoring of the sterility and/or cleanliness and/or efficiency of the circuit in which the unit is used, or the system in which the circuit is used or the unit is used. For the distal end, the first sealing element 9B is in radial abutment between said lateral walls 4 and 6, and the second sealing element 10B is in axial abutment between said lateral wall 6 and the shoulder 14 of the lateral wall 4. In this way, a further increase in hygiene of the filter unit 1 is achieved. In particular, the sealing element 10B can define, by deforming, a continuous surface that connects the inner surface 20 of the filter body 3 and the inner surface 19 of the terminal portion B, so as to reduce and/or eliminate the presence of hard-to-wash gaps. Deformation of each of the sealing elements 9B and 9A can define, in the same way, a continuous surface that connects the lateral wall 4 to the lateral wall 6, so as to reduce and/or eliminate the presence of hard-to-wash gaps. The locking element 22 keeps the filter body 3 in the housing so as to press the sealing element 10B against the shoulder 14. Thirdly, the filter unit 1 is easily cleaned. In particular, by making the fluid flow in the first direction (namely, with radial inlet in correspondence of the passage mouth 30 and axial outlet in correspondence of the distal end ED), impurities (solid or semi-solid) are retained externally on the filter body 3 (namely, on the side of the filter body 3 facing the gap 8), which allows the user to easily clean the filter body 3, by simply slipping it out of the outer housing 2. In addition, in the embodiment in which the terminal portion B is coradial with the lateral wall 6, the filter unit 1 has no fluid stagnation areas in proximity to the end ED (which may be the fluid outlet or inlet, as previously described). Further fluid stagnation areas can be eliminated by making the passage mouth 30 tangent to the outer housing 2. Lastly, by using the filter unit 1 described above in the circuit and/or packaging system, it is possible to meet the degree of sterility required by current regulations that are increasingly stringent. LIST OF REFERENCE NUMBERS OF THE FIGURES 1 filter unit 2 outer housing 3 filter body 4 lateral wall 5 receiving space 6 lateral wall 7 through openings 8 gap 9 sealing element 10 sealing element 11 control chamber 12 control chamber 13 seat 14 shoulder 15 control opening 16 closing wall 17 inner surface 18 inner surface 19 inner surface 20 inner surface 21 handle 22 locking element 30 passage mouth A terminal portion B terminal portion C intermediate portion X axis Y axis

Claims

CLAIMS 1. Filter unit (1) for filtering a fluid comprising: an outer housing (2) comprising a first lateral wall (4), which delimits a receiving space (5); and a filter body (3) comprising a second lateral wall (6) provided with a plurality of through openings (7) configured to filter the fluid; the filter body (3) is housed in the receiving space (5) in such a way as to define a gap (8) between the two lateral walls (4, 6); the filter body (3) has a proximal end (EP) and a distal end (ED), which is opposite the proximal end (EP), and each of which has a respective first sealing element (9) and a respective second sealing element (10); both sealing elements (9, 10) of each end (EP, ED) are arranged in succession one behind the other and between the two lateral walls (4, 6) to define a respective control chamber (11, 12) between them, which is separate and different from the gap (8) and is configured to detect fluid leaks from the gap (8) itself; characterized in that, for at least one of these ends (EP, ED) and with respect to the first axis (X), one of the respective sealing elements (9B, 10B) is in radial abutment between said lateral walls (4, 6), and the other (10B) is in axial abutment between said second lateral wall (6) and a shoulder (14) of said first lateral wall (4).

2. Filter unit (1) according to claim 1, wherein the first lateral wall (4) has at least one control opening (15) in correspondence with each control chamber (11, 12) which is through and is configured for allow the inspection of the respective control chamber (11, 12) itself.

3. Filter unit (1) according to claim 1 or 2, in which the outer housing (2) and the filter body (3) each have a cylindrical shape and are both arranged coaxial to a first axis (X) which extends longitudinally between the proximal end (EP) and the distal end (ED); and the gap (8) and each control chamber (11, 12) have an annular shape, are coaxial to the first axis (X) and the gap (8) is axially arranged between the two control chambers (11, 12).

4. Filter unit (1) according to claim 3, comprising a passage mouth (30) of the fluid, which projects from the outer housing (2) and which is provided with a second axis (Y) which is transverse, in particular orthogonal, with respect to the first axis (X); in which the filter unit (1) is configured for: let the fluid enter in correspondence of the passage mouth (30) in the outer housing (2) and after passing through the filter body (3), to let the fluid flow out coaxially to the first axis (X) in correspondence of the distal end (ED); or allow the fluid to enter in correspondence of the distal end (ED) into the filter body (3) and then to pass through the filter body (3) in the gap (8), to let the fluid flow out of the outer housing (2) transversely, in particular orthogonally, to the first axis (X) in correspondence of the passage mouth (30).

5. Filter unit (1) according to claim 4, wherein the first axis (X) and the second axis (Y) are incident to each other.

6. Filter unit (1) according to claim 4, wherein the first (X) and the second axis (Y) are skewed to each other.

7. Filter unit (1) according to claim 6, wherein at least a portion of an inner surface (17) of the passage mouth (30) is arranged tangent to an inner surface (18) of the outer housing (2).

8. Filter unit (1) according to any one of the previous claims, in which the outer housing (2) has: a first terminal portion (A) and a second terminal portion (B), each of which is configured to cooperate with the respective two sealing elements (9, 10) of the respective end (EP, ED) of the filter body (3), and an intermediate portion (C) which is interposed between the two terminal portions (A, B) and from which the passage mouth (30) projects.

9. Filter unit (1) according to claim 8, in which the two terminal portions (A, B) and the intermediate portion (C) are made without solution of continuity.

10. Filter unit (1) according to claim 8, in which the two terminal portions (A, B) are made with a solution of continuity and are connected, in particular welded, with the intermediate portion (C).

11. Filter unit (1) according to any one of claims 1 to 10, wherein the filter body (3) has a handle (19) for inserting the filter body (3) inside the outer housing (2) or for extracting the filter body (3) from inside the outer housing (2).

12. Filter unit (1) according to any one of claims 1 to 11, comprising a locking element (20) configured to lock the filter body (3) with respect to the outer housing (2), in particular by means of a threaded connection between the locking element (22) and the outer housing (2).

13. Circuit for feeding a fluid comprising the filter unit (1) made in accordance with one of claims 1 to 12.

14. Packaging plant for a pourable product comprising the filter unit (1) made in accordance with one of claims 1 to 12 or the circuit made in accordance with claim 13.