FILTER AND SEPARATION DEVICE

Description

[0001] The invention relates to a filter device according to the preamble of claim 1, a separation device according to claim 11 and the use of a filter device according to claim 12.

[0002] Filter devices are used to retain undesirable substances from a fluid. For example, coalescence separators are known, which serve to separate a medium from a medium to be cleaned. For this purpose, they use a filter element made of a material that is more difficult for the medium to be separated to penetrate than for the medium to be cleaned. In this way, larger droplets of the medium to be separated form within the filter element. Once they reach the outlet side of the filter element, these droplets sink or rise due to their size and a density difference compared to the medium to be cleaned and can be collected in a designated collection chamber. This collection chamber can then be emptied.

[0003] For example, it is known from DE 38 18 595 A1 that a coalescing separator can be manufactured by using a perforated support tube as a wound core for a glass fiber-reinforced polyamide mat, so that the polyamide mat wound in multiple layers onto the support tube forms a filter element. The support tube is then closed at its ends with a first end plate, which forms an inlet, and a sealing second end plate. The coalescing separator is then used to introduce hydrocarbons containing free water through the inlet into the support tube and to transport them from the inside to the outside through the filter element. The free water is retained and forms droplets that, as soon as they reach the outer surface of the filter element, flow downwards.

[0004] A similar wrapping of a mat-like glass fiber material around a support core to form a filter device or coalescing separator is also described in DE 21 26 080 C3. Additionally, a pleated filter is arranged within the support tube, through which flow flows from the inside to the outside and filters out solids in a pre-filter stage. The pleated filter is supported on the inside of the support tube. In various applications of such filter devices, it was observed that the filter performance deteriorates significantly after a short period of use. This could be attributed to cracks in the pleated filter. Tests to analyze crack damage have now shown that at higher backflow velocities, the pleated filter is compressed to the point of collapse, causing irreparable damage.Depending on the application, such backflow can occur when the forward flow is switched off, for example when the fluid flows backwards into a lower tank.

[0005] US 3,279,607 A discloses a pleated filter in whose cylindrical passage a support body in the form of a helical spring is located. This spring serves to maintain the cylindrical passage. GB 401 287 A teaches the use of a strong spiral spring in a similar pleated filter to support the pleated element so that it is held against an outer, perforated tube, particularly during the intended flow from the outside to the inside. Furthermore, US 2,642,187 A discloses a support body that is designed either as a helical coil or as a perforated tube, wherein the support body serves to support the inner diameter of a pleated filter.

[0006] Furthermore, DE 10 2018 108 986 A1 describes a filter element for a coalescence separator.

[0007] Based on this, the task arose to prevent damage to the pleated filter in order to increase the service life of the coalescing separator. The solution should be cost-effective and reliable, as well as, if possible, not reduce the efficiency of the coalescing separator or the filter device in the normal flow direction.

[0008] Main features of the invention are set out in the characterizing part of claim 1 and claims 11 and 12. Embodiments are the subject of claims 2 to 10 and the description.

[0009] The invention relates to a filter device comprising a support tube having an inner side and an outer side, which forms an interior space on the inner side into which an inlet opening opens, and which has passage openings that connect the interior space with an ambient space located on the outer side of the support tube. The filter device further comprises a first filter element having an inner side and an outer side, wherein the first filter element is arranged in the interior of the support tube and with its outer side adjacent to the inside of the support tube. It is provided that a support body is arranged in the interior of the support tube and adjacent to the inside of the first filter element.

[0010] The advantage of this is that, according to the invention, the first filter element can be supported on the support body during backflow. This prevents the first filter element from collapsing and / or collapsing during backflow.

[0011] According to a more detailed embodiment of the filter device, the support body extends along the support tube, in particular also along the first filter element. This allows the support body to support the first filter element evenly.

[0012] In a special embodiment, the first filter element is a pleated filter. While such pleated filters have a relatively high level of inherent stability, they fail relatively suddenly when a limiting backflow volume flow is exceeded, usually resulting in cracks in the area of ​​the pleats. The support body can reliably prevent this. Such pleated filters have pleats. These can wind along the support tube or, like a bellows, be aligned transversely to the support tube. However, the pleats particularly preferably extend along the support tube, particularly linearly. Pleats of the latter type, in particular, result in low inherent stability under transverse loads such as backflow, so the support body represents an effective means of support.

[0013] According to the invention, the support body is in the shape of a helix, coil, or screw. This is simple and cost-effective to manufacture, offers homogeneously distributed support points, has high inherent stability with low weight and material usage, and allows airflow through the interior in the longitudinal direction. A helix is ​​a curve that winds around the surface of a cylinder at a constant gradient.

[0014] Specifically, the pitch angle of the support body can be greater than 20 degrees, preferably greater than 25 degrees. This keeps a large portion of the inside of the first filter element free for flow. A design in which the pitch of the support body is at least 50%, preferably at least 70%, of the total diameter of the support body can also contribute to this.

[0015] A cost-effective variant has a single-threaded support body. This is usually structurally sufficiently stable for support and particularly easy to manufacture.

[0016] According to the invention, the support body is a helical spring, in particular a helical compression spring. Such a spring is particularly easy to install. The helical spring according to the invention elastically returns to its original shape after installation or when subjected to backflow loads. At the same time, it deforms during backflow, thus reducing load peaks at the support points of the first filter element.

[0017] Optionally, the support body can be made of plastic and / or metal, for example.

[0018] Furthermore, the filter device can be designed so that the material cross-sectional area of ​​the support body amounts to a maximum of 10%, preferably a maximum of 5%, of the total cross-sectional area of ​​the support body. This results in a delicate support body with minimal material usage, which has the least possible impact on the fluid flows in the interior of the support tube.

[0019] High stability with low material usage can also be achieved, among other things, by a design according to which the support body has a round material cross-sectional area and / or total cross-sectional area.

[0020] The support element according to the invention is particularly effective in that the support tube and the first filter element are loosely adjacent to one another in a central region and are sealed to one another (only) in the area of ​​the two ends of the support tube. This central region is particularly unstable in the event of backflow and is effectively supported by the support body.

[0021] A closure element can be arranged in the area of ​​each end of the support tube. The inlet opening is then preferably formed in one of the closure elements.

[0022] For multi-stage treatment of a fluid with the filter device, a second filter element is located on the outside of the support tube.

[0023] For the coalescing treatment of the fluid, at least one filter layer of the second filter element is hydrophobic. This allows, for example, free water to be removed from a fuel.

[0024] Alternatively, at least one filter layer of the second filter element can be hydrophilic. This is suitable, for example, for separating free oil from water.

[0025] Furthermore, according to the invention, the filter device comprises a protective sheath surrounding the filter element. The protective sheath is a hydrophilic textile, particularly preferably a hydrophilic cotton sock. The hydrophilicity promotes the drainage of large droplets of the fluid to be separated. A cotton sock is particularly cost-effective.

[0026] The invention also relates to a separation device with a filter device as described above and below, and with a filter housing with an interior space in which the filter device is arranged, wherein a housing inlet opens into the inlet opening of the filter device, wherein the interior space of the support tube is connected to the interior space of the filter housing via the passage openings, and wherein a housing outlet opens out of the interior space of the filter housing.

[0027] Optionally, a collection volume can be formed below the filter device in the filter housing, wherein a housing drain opens out of the filter housing above the collection volume.

[0028] Finally, the invention relates to the use of a filter device as described above and below, wherein a second filter element is located on the outside of the support tube, wherein at least one filter layer of the second filter element is hydrophobic, when a hydrocarbon-based fluid flows through it, wherein the first filter element filters out solids from the fluid, and wherein the second filter element separates free water from the fluid.

[0029] Further features, details, and advantages of the invention will become apparent from the wording of the claims and from the following description of exemplary embodiments with reference to the drawings. They show: Fig. 1 shows a longitudinal section through a filter device; and Fig. 2 shows a cross section through a filter device.

[0030] Fig. 1 shows a longitudinal section and Fig. 2a cross-section through a filter device 1. The same reference numerals therefore refer to equivalent components and the Fig. 1 and 2 are described together. The filter device 1 has a support tube 10 with an inner side 11 and an outer side 12, wherein an interior space IR is formed on the inner side 11. The support tube 10 is closed at its end with closure elements 15, 16, with an inlet opening 13 opening into the interior space IR through one of the closure elements 15. Through-openings 14 are formed in the support tube 10, which connect the interior space IR with an ambient space UR located on the outer side 12 of the support tube 10.

[0031] A first filter element 20, in particular a pleated filter, is located in the support tube 10. Its outer side 22 is arranged adjacent to the inner side 11 of the support tube 10. Pleats 23 of the first filter element 20 extend along the support tube 10.

[0032] Furthermore, a support body 30 is arranged in the interior space IR of the support tube 10 and adjacent to the inner side 21 of the first filter element 20. This extends along the support tube 10. The support body 30 has the shape of a single-start helix, i.e., a curve that winds around the surface of a cylinder at a constant pitch. The pitch angle W of the helical support body 30 is greater than 20 degrees. The pitch H of the helical support body 30 is more than 50% of the total diameter D of the support body 30. A round material cross-sectional area A of the support body 30 is less than 10% of the round total cross-sectional area Q of the support body 30. In particular, the support body 30 is a helical compression spring made of metal.

[0033] The support tube 10 and the first filter element 20 lie loosely against each other in a central region and are sealed to each other exclusively in the region of the two ends of the support tube 10, in particular adjacent to the closure elements 15, 16.

[0034] On the outer side 12 of the support tube 10 there is a second filter element 40 with several filter layer layers 41. At least one of these can be designed to be hydrophilic or hydrophobic, for example.

[0035] If the filter device 1 is flowed through with a fluid F1 consisting of a hydrocarbon, as shown in Fig. 2 As indicated, the first filter element 20 filters out solids S from the fluid F1. The second filter element 40 separates free water F2 from the fluid F1. List of reference symbols

[0036] 1 filter device 40 second filter element 10 support tube 41 Filter layer 11 inside 12 outside A Material cross-sectional area 13 Entrance opening D Total diameter 14 Passage opening F1 Fluid 15 locking element F2 free water 16 locking element H Pitch IR Interior 20 first filter element Q Total cross-sectional area 21 inside S Solids 22 outside UR surrounding space 23 fold W Gear angle 30 Support body

Claims

1. Filter device (1) comprising a supporting tube (10) - which has an inner side (11) and an outer side (12), - which on the inner side (11) forms an inner space (IR) into which an inlet opening (13) leads, and - which has through-openings (14) connecting the inner space (IR) to a surrounding space (UR) lying on the outer side (12) of the supporting tube (10), and comprising a first filter element (20) which has an inner side (21) and an outer side (22), the first filter element (20) being arranged in the inner space (IR) of the supporting tube (10) and with its outer side (22) adjacent to the inner side (11) of the supporting tube (10), wherein the supporting tube (10) and the first filter element (20) loosely adjoin one another in a centre region and are sealed with respect to one another in the region of the two ends of the supporting tube (10), wherein a second filter element (40) sits on the outer side (12) of the supporting tube (10), at least one filter layer (41) of the second filter element (40) being hydrophobic, and wherein the filter device (1) has a protective sleeve surrounding the filter element, wherein the protective sleeve is a hydrophilic textile, characterized in that a supporting body (30) is arranged in the inner space (IR) of the supporting tube (10) and adjacent to the inner side (21) of the first filter element (20), with the result that, when backflow is occurring, the first filter element (20) can be supported against the supporting body (30) and thereby prevent collapse and / or subsidence of the first filter element (20) when backflow is occurring, wherein the supporting body (30) has the form of a helix, a coil or a screw, wherein the supporting body (30) is that type of helical spring - that deforms when backflow is occurring and thus reduces loading peaks at the support points of the first filter element (20), and - elastically deforms back into the starting form after being subjected to a backflow loading.

2. Filter device (1) according to Claim 1, characterized in that the supporting body (30) extends along the supporting tube (10).

3. Filter device (1) according to either of Claims 1 and 2, characterized in that the first filter element (20) is a pleated filter.

4. Filter device (1) according to any of the preceding claims, characterized in that a pitch angle (W) of the supporting body (30) is greater than 20 degrees, preferably greater than 25 degrees.

5. Filter device (1) according to any of the preceding claims, characterized in that a pitch (H) of the supporting body (30) is at least 50%, preferably at least 70% of the total diameter (D) of the supporting body (30).

6. Filter device (1) according to any of the preceding claims, characterized in that the supporting body (30) has a single-start form.

7. Filter device (1) according to any of the preceding claims, characterized in that the supporting body (30) is a helical compression spring.

8. Filter device (1) according to any of the preceding claims, characterized in that a material cross-sectional area (A) of the supporting body (30) is at most 10%, preferably at most 5% of the overall cross-sectional area (Q) of the supporting body (30).

9. Filter device (1) according to any of the preceding claims, characterized in that the supporting body (30) has a round material cross-sectional area (A) and / or overall cross-sectional area (Q).

10. Filter device (1) according to any of the preceding claims, characterized in that at least one filter layer (41) of the second filter element (40) is hydrophilic.

11. Separating apparatus comprising a filter device (1) according to any of the preceding claims and comprising a filter housing which has an inner space in which the filter device (1) is arranged, wherein a housing inflow leads into the inlet opening (13) of the filter device (1), wherein the inner space (IR) of the supporting tube (10) is connected to the inner space of the filter housing via the through-openings (14), and wherein a housing outflow leads out of the inner space of the filter housing.

12. Use of a filter device (1) according to any of Claims 1 to 10 when a hydrocarbon-based fluid (F1) is flowing therethrough, wherein solids (S) are filtered out of the fluid (F1) by means of the first filter element (20), and wherein free water (F2) is separated off from the fluid (F1) by means of the second filter element (40).