Coalescence Element and Filter Element Having a Coalescence Element

Abstract

A coalescence element is provided with at least one coalescence medium configured to coalesce water contained in a fluid. The at least one coalescence medium is made of a material with a packing density of at most 10%. The coalescence element is embodied as a single layer formed as a cylindrical jacket and has a fluid path for a fluid between an inlet side and an outlet side of the cylindrical jacket. A filter element with a filter bellows and a support pipe arranged coaxially inside the filter bellows is provided with such coalescence element that is arranged between the filter bellows and the support pipe in the flow direction so as to surround the support pipe at a radial outer side.

Claims

1. A coalescence element embodied as a single layer formed as a cylindrical jacket and comprising a fluid path for a fluid between an inlet side and an outlet side of the cylindrical jacket, the coalescing element comprising at least one coalescence medium configured to coalesce water contained in the fluid and comprised of a material with a packing density of at most 10%.

2. The coalescence element according to claim 1, wherein the packing density is at most 8% and at least 2%.

3. The coalescence element according to claim 1, wherein the material of the at least one coalescence medium comprises an average pore size of at least 100 m.

4. The coalescence element according to claim 1, wherein the at least one coalescence medium is comprised of polyester and the at least one coalescence medium comprises a thickness in a range between 2 mm and 5 mm.

5. The coalescence element according to claim 4, wherein the at least one coalescence medium comprises an air permeability of at least 1,000 l/cm.sup.2 h.

6. The coalescence element according to claim 1, wherein the at least one coalescence medium is comprised of polyester and the at least one coalescence medium comprises an air permeability of at least 1,000 l/cm.sup.2 h.

7. The coalescence element according to claim 1, wherein the at least one coalescence medium is comprised of viscose and the at least one coalescence medium comprises a thickness in a range between 0.5 mm and 4 mm.

8. The coalescence element according to claim 7, wherein the at least one coalescence medium comprises an air permeability of at least 1,000 l/cm.sup.2 h.

9. The coalescence element according to claim 1, wherein the at least one coalescence medium is comprised of viscose and the at least one coalescence medium comprises an air permeability of at least 1,000 l/cm.sup.2 h.

10. The coalescence element according to claim 1, further comprising a final separator arranged at the outlet side, wherein the final separator is comprised of a hydrophobic material or a material with a hydrophobic surface.

11. The coalescence element according to claim 10, wherein the final separator comprises a mesh size of 40 m.

12. The coalescence element according to claim 1, further comprising end disks that are fluid-tightly connected to oppositely positioned end faces of the cylindrical jacket.

13. A filter element comprising: a raw side and a clean side and a flow path for a fluid to be filtered in a flow direction from the raw side to the clean side; at least one filter bellows comprising oppositely positioned end faces; end disks fluid-tightly connected to the oppositely positioned end faces of the at least one filter bellows; at least one support pipe arranged coaxially inside the at least one filter bellows, the at least one support pipe connected to the end disks, wherein the at least one support pipe comprises passages allowing the fluid to be filtered to pass through the at least one support pipe; at least one coalescence element embodied as a single layer formed as a cylindrical jacket and comprising a fluid path for the fluid to be filtered between an inlet side and an outlet side of the cylindrical jacket, the coalescing element comprising at least one coalescence medium configured to coalesce water contained in the fluid to be filtered and comprised of a material with a packing density of at most 10%. wherein the cylindrical jacket of the at least one coalescence element is arranged between the at least one filter bellows and the at least one support pipe in the flow direction and surrounds the at least one support pipe at a radial outer side of the at least one support pipe.

14. The filter element according to claim 13, wherein a shape of the coalescence element is supported and stabilized between the at least one filter bellows and the at least one support pipe.

15. The filter element according to claim 13, wherein the at least one filter bellows comprises a hollow cylindrical shape and wherein the fluid path extends radially through the at least one filter bellows and the at least one coalescence element.

16. The filter element according to claim 15, wherein the flow direction of the fluid path extends radially from an exterior region to an interior region of the hollow cylindrical shape of the at least one filter bellows.

17. The filter element according to claim 13, wherein the coalescence element is arranged at a clean side of the at least one filter bellows.

18. A filter system for filtering a fluid, the filter system comprising: a filter housing; a filter element arranged in the filter housing and comprising a raw side and a clean side and a flow path for a fluid to be filtered in a flow direction from the raw side to the clean side; wherein the filter element comprises at least one filter bellows comprising oppositely positioned end faces, wherein the end disks are fluid-tightly connected to the oppositely positioned end faces of the at least one filter bellows; wherein the filter element further comprises at least one support pipe arranged coaxially inside the at least one filter bellows, the at least one support pipe connected to the end disks, wherein the at least one support pipe comprises passages allowing the fluid to be filtered to pass through the at least one support pipe; wherein the filter element further comprises at least one coalescence element embodied as a single layer formed as a cylindrical jacket and comprising a fluid path for the fluid to be filtered between an inlet side and an outlet side of the cylindrical jacket, the coalescing element comprising at least one coalescence medium configured to coalesce water contained in the fluid to be filtered and comprised of a material with a packing density of at most 10%. wherein the cylindrical jacket of the at least one coalescence element is arranged between the at least one filter bellows and the at least one support pipe in the flow direction and surrounds the at least one support pipe at a radial outer side of the at least one support pipe. wherein the at least one coalescence element of the filter element is arranged at a clean side of the filter element.

19. The filter system according to claim 18, wherein the at least one filter bellows is a hollow cylindrical filter bellows.

20. The filter system according to claim 18, wherein the filter element further comprises a final separator arranged inside the filter element at the clean side.

21. The filter system according to claim 18, configured as a fuel filter system.

22. The filter system according to claim 18, configured as a prefilter or a suction-side filter system of a fuel supply system of an internal combustion engine.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0053] Further advantages result from the following FIGURE description. In the drawing, embodiments of the invention are illustrated. The drawing, the description, and the claims contain numerous features in combination. A person of skill in the art will consider the features expediently also individually and combine them to other expedient combinations.

[0054] FIG. 1 shows a longitudinal section of a filter system according to an embodiment of the invention for the fuel filtration in a motor vehicle with a single-layer coalescence element.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0055] In the FIGURES, same or same-type components are identified with same reference characters. The FIGURES show only examples and are not to be understood as limiting.

[0056] The invention is illustrated with the aid of a fuel filter for filtering fuel, in particular diesel fuel, but can also be provided for other filter systems with appropriate adaptation of the construction.

[0057] FIG. 1 shows a longitudinal section of a filter system 100 according to an embodiment of the invention for the fuel filtration in a motor vehicle with a single-layer coalescence element 30. The filter system 100 comprises a filter element 10 arranged in a filter housing 108 for filtering a fluid, wherein the filter element 10 provides at its clean side 50 a coalescence element 30 for coalescing water contained in the fluid. The filter element 10 is inserted as a round filter element in a round filter housing 108 which is comprised of a housing top part 112 and a housing bottom part 114. The filter element 10 is centrally seated in the housing 108 and is clamped with two end disks 16, 18 in the filter housing 108. Within the filter element 10, a final separator 106 is arranged at a clean side 50 and covers the entire fluid path 40 because the final separator 106 projects at both end faces 15, 17 past the filter element 10 and is connected fluid-tightly with the housing top part 112 and the housing bottom part 114. Fluid is supplied to the filter housing 108 from the exterior by an inlet, not illustrated, and passes from the radial outer side through the filter element 10 and can reach an interior of the filter housing 108 through the filter bellows 12, the coalescence element 30 as well as the final separator 106. The filtered fluid is then discharged via this interior through an outlet 104, illustrated in FIG. 1 at the top.

[0058] The separated water is collected in a water collecting space 116 from where it can be discharged to the exterior. For this purpose, the filter system 100 can be screwed with this water collecting space 116 by a screw thread 110 onto a connecting socket (not illustrated).

[0059] The filter element 10 for filtering a fluid, with the fluid path 40 between a raw side 52 and a clean side 50, comprises a filter bellows 12 which is fluid-tightly connected at its oppositely positioned end faces 15, 17 to an end disk 16, 18, respectively. The filter element 10 comprises furthermore a support pipe 14 which is coaxially arranged within the filter bellows 12 and which is connected with the two end disks 16, 18 and which comprises passages 20 for flow of the fluid therethrough. Furthermore, the filter element 10 comprises a coalescence element 30 with a coalescence medium 32 which is arranged in the flow direction between the filter bellows 12 and the support pipe 14 and which is provided for coalescing water contained in the fluid. The coalescence element 30 is of a single-layer configuration and surrounds the support pipe 14 as a cylindrical jacket at a radial outer side 22. The fluid flows through the coalescence element 30 from an inlet side 53 to an outlet side 51.

[0060] The coalescence medium 32 is preferably formed of a material with a packing density of at most 10%, in particular at least 2%, for example of 6%. The coalescence medium 32 can comprise an average pore size of at least 100 m. The coalescence medium 32 is expediently made of polyester wherein the coalescence medium 32 has a thickness in a range between 2 mm and 5 mm, preferably in a range between 2.8 mm and 4 mm, and/or an air permeability of at least 1,000 l/cm.sup.2 h, preferably of at least 1,500 l/cm.sup.2 h, particularly preferred up to 4,500 l/cm.sup.2 h. Alternatively, it is also conceivable that the coalescence medium 32 is made of viscose wherein the coalescence medium 32 then has a thickness in a range between 0.5 mm and 4 mm, preferably of 1 mm and 3 mm, and/or an air permeability of at least 1,000 l/cm.sup.2 h, preferably up to 3,000 l/cm.sup.2 h.

[0061] The coalescence element 30 is fluid-tightly connected to the two end disks 16, 18 and is supported in a shape-stabilizing way between the filter bellows 12 and the support pipe 14. The filter bellows 12 is embodied of a hollow cylindrical shape wherein the fluid path 40 extends radially through the filter bellows 12 and the coalescence element 30, in particular from an outer region 42 into an inner region 44 of the hollow cylindrical shape. The coalescence element 30 is thus arranged at the clean side 50 of the filter bellows 12.

[0062] Free water in the fluid is guided mostly through the filter bellows 12. In the coalescence medium 32, the small water drops are enlarged as they pass through the coalescence element 30. In the gap between the coalescence element 30 and the final separator 106, large drops, assisted by gravity, fall downwardly into a collecting space 116 of the filter system 100 from where the collected water, for example, by means of a screw, is drained to the exterior during servicing.

[0063] Smaller drops which are initially not falling downwardly due to gravity are hindered by the hydrophobic surface of the final separator 106 from passing to the clean side 50 and also fall downwardly into the collecting space. The final separator 106 is made of a hydrophobic material, in particular of PET, and comprises preferably a mesh size of 40 m. Water drops with a drop size that is smaller than the mesh size of the final separator, which is, for example, 40 m, pass through the final separator 106 to the clean side 50 and are comminuted in a downstream low-pressure pump so that they can be separated in a downstream main filter.