Filter

Abstract

2. The invention relates to a filter for treating process fluid such as that which in particular arises during hydrogen electrolysis, preferably for separating hydrogen and / or oxygen from process water, having a first filter element (10) and a second filter element (12), which encloses the first filter element (10) with the formation of a flow space (14) with a predefinable radial spacing, wherein each filter element (10, 12) has a filter medium (16, 18) through which the process fluid can flow in a flow-through direction (24) from the outside to the inside or preferably from the inside to the outside, wherein, seen in the flow-through direction (24), the one filter medium (16) forms a first degassing stage, which is used to enlarge gas bubbles through coalescence and to remove same from the process fluid through separation caused by buoyancy, and the subsequent further filter medium (18) forms a second degassing stage, which is used to remove very finely distributed gas bubbles remaining in the process fluid, again through coalescence and the separation of same through rising caused by buoyancy.

Description

[0001] filter

[0002] The invention relates to a filter for treating process fluid, such as is produced in particular during hydrogen electrolysis, preferably for separating hydrogen and / or oxygen from process water.

[0003] DE 10 2021 001 631 A1 discloses a method for treating process fluids such as those produced by decomposing a process fluid into different process gases with the aid of electrical current in an electrolysis cell, comprising at least one fluid circuit in which at least one of the process gases is present in the form contained in the process fluid to form the process fluid, wherein at least one fluid storage tank is present as part of the fluid circuit, in which at least one filter device is accommodated, by means of which the process fluid is cleaned of any particle contamination and at the same time the contained process gas is separated from the process fluid while retaining the process fluid.The filter device used here and known in this respect has a preferably replaceable filter element through which a fluid can flow from the inside to the outside, wherein the filter element is surrounded by a housing wall while maintaining a predeterminable radial distance and forming a fluid flow space, which is designed as an outflow pipe and has a plurality of passage points, one part of which is arranged below the respective variable fluid level in the fluid storage tank and the other part above this fluid level.

[0004] Based on this prior art, the object of the invention is to further improve the known solution while retaining its advantages, in particular to achieve an even higher rate of separated gas from a process fluid.

[0005] A filter having the features of patent claim 1 in its entirety solves this problem.

[0006] The filter according to the invention has a first filter element and a second filter element which surrounds the first filter element to form a flow space with a predeterminable radial distance, wherein each filter element has a filter medium through which the process fluid can flow from the outside inwards or preferably from the inside outwards in a flow direction, wherein, viewed in the flow direction, one filter medium forms a first degassing stage which serves to enlarge gas bubbles by coalescence and to remove them from the process fluid by buoyancy-induced separation, and the subsequent further filter medium forms a second degassing stage which serves to remove finely distributed gas bubbles remaining in the process fluid by coalescence and to separate them again by buoyancy-induced rising.

[0007] This creates a two-stage degassing filter in a single unit, which significantly improves the separation of fluid and gas compared to the conventional solution. In the hydrogen electrolysis process mentioned above, oxygen and hydrogen are released from the process water, the process fluid, during the process. Due to the nature of the process, two separate fluid circuits exist for both hydrogen and oxygen: one circuit with water and free hydrogen bubbles, and another with water and free oxygen bubbles. A separate separator is used for each of these circuits, whose task is to separate the corresponding gas from the liquid.The gas contents that can arise during the process can easily range between 30 and 95 percent by volume. With the degassing filter according to the invention, with its improved degassing rates, a significant reduction in the respective separator size or volume can be achieved. Thanks to the resulting savings in installation space, the filter according to the invention can be increasingly used for a variety of practical applications. Preferably, the filter media used for the first and second elements differ from each other depending on the degassing task to be solved.

[0008] In a preferred embodiment of the filter according to the invention, the one filter medium preceding it in the flow direction consists of a depth filter candle, which is designed as a hollow cylindrical filter shell to increase the filter volume. This results in a coaxial arrangement of two filter stages that serve to degas a process fluid, with the first filter stage leading to an initial coalescence of the gas bubbles, which then increase in volume accordingly, rise due to buoyancy, and are thus separated from the process fluid. The air bubbles not yet separated are then retained by the second degassing stage and again fed to a coalescence process, so that the gas bubbles, which are now also finely dispersed in the fluid, increase in volume, rise due to buoyancy, and are then likewise separated from the process fluid, usually in the form of process water.Particularly preferably, the filter uses meltblown fibers to form the depth filter cartridge, which are preferably sprayed onto a fluid-permeable support body against which the filter shell rests along its inner circumference. The depth filter cartridge used is designed to be significantly more voluminous than a pleated element material, resulting in improved gas removal behavior. The meltblown depth filter cartridge thus forms a hollow-cylindrical, solid filter shell block with a predeterminable porosity.

[0009] Instead of constructing the depth filter candle from meltblown fibers, it is also possible to construct it from a sintered material, either in the form of a sintered metal filter or in the form of a ceramic filter, each with a predeterminable filter permeability.

[0010] For reliable degassing processes with high separation rates, it has proven advantageous to select a depth filter cartridge fineness between 10 fjm and 200 fjm. If meltblown fibers are used extensively or exclusively for the depth filter cartridge, the fiber diameter is preferably between 0.1 fjm and 2000 fjm, and the mean flow pore size (MFP) is preferably between 1 fjm and 2000 fjm.

[0011] For a pure construction of the filter, all essential components are preferably made of one and the same plastic material and if metals are used as the filter medium for the filter, such as stainless steel or titanium, it is preferably provided that in any case all filter media are made of one and the same metal material.

[0012] Particularly preferably, it can be provided that the filter medium following the one filter medium in the flow direction has at least a two-layer, preferably three-layer mat structure, which allows additionally improved particle cleaning from the fluid flow. Furthermore, the invention relates to a device with a container for accommodating at least one filter as described above, wherein the container has at least one inlet for gas-containing process fluid and an outlet for the gas separated in the container and a further outlet for the process fluid freed from the gas, wherein the respective filter flows from the inside to the outside from the inlet of the container, above a fluid level in the container passes the separated gas to one outlet in the container and below this fluid level process fluid collected in the container is discharged from the container via the further outlet.Preferably, it is provided that a parallel flow to the respective filter in the container takes place from below via openings in a separating plate in the container, which extends parallel to the fluid level that occurs during operation, and that a suction connection is provided between the individual filters, which opens out above the adapter plate and below the fluid level in the container and is connected to the further outlet for the process fluid.

[0013] In the following, the filter according to the invention is explained in more detail using various embodiments and in the context of a container installation according to the drawing. The drawings show, in a schematic and not to scale representation, the

[0014] Figure 1 is a perspective view of a filter;

[0015] Figures 2 and 3 show, in the form of a longitudinal section through Figure 1, two different embodiments of the filter;

[0016] Figures 4, 5 and 6, 7 are enlarged views of the head and foot of the filter according to Figure 2 and of the filter according to Figure 3, respectively; and Figures 8 and 9 are side and top views of the installation situation of filters according to Figures 1 to 3 in a container.

[0017] Figures 2, 4, and 5 relate to a first embodiment of the filter according to the invention. This filter is used to treat process fluid, such as that produced in particular during hydrogen electrolysis, preferably for separating hydrogen and / or oxygen from process water. The filter comprises, in one structural unit, a first filter element 10 and a second filter element 12, which surrounds the first filter element 10, forming a flow space 14 with a predeterminable radial spacing.

[0018] It is further provided that the first filter element 10 has a first filter medium 16 and the second filter element 12 has a second filter medium 18. The first filter medium 16 is supported on the inner circumference by a fluid-permeable support body 20 in the form of a support grid. The second filter medium 18 is enclosed on the outer circumference by a further fluid-permeable support body 22, which is also designed in the manner of a support grid. Further fluid-permeable support bodies (not shown) can, if necessary, be arranged on the outer circumference of the first filter medium 16 and on the inner circumference of the second filter medium 18. In the present case, flow through the filter takes place in the flow direction from the inside to the outside, wherein the relevant flow direction is represented in Figure 2 by an arrow 24.

[0019] The first filter medium 16, together with its inner support body 20, is held between an upper end cap 26 and a lower end cap 28. The second filter medium 18, together with the further support body 22, is held between the same end caps 26, 28 and with the correspondingly identical axial length. To this extent, the respective front ends of the first and second filter medium 16, 18, as well as the two support bodies 20, 22, are firmly or fluid-tightly connected to the end caps 26, 28, preferably using a mirror welding process. Further details regarding the end caps 26, 28 will be described in more detail below. Again viewed in the flow direction 24, the first filter medium 16 forms a first degassing stage, which serves to enlarge gas bubbles through coalescence and to remove them from the process fluid through buoyancy-induced separation.The subsequent additional filter medium 18 forms a second degassing stage, which serves to remove the remaining, finely distributed gas bubbles in the process fluid through coalescence and to separate them by buoyancy-induced ascent. The first degassing stage, formed by the first filter element 10 as a whole, thus serves to enlarge existing gas bubbles, which then ascend in the process fluid and are thus separated on the surface of the process fluid. The second filter element 12, which in this respect forms the second degassing stage, serves to further separate the remaining, finely distributed gas bubbles in the process fluid through coalescence into larger bubble arrangements and separation by buoyancy-induced ascent.

[0020] In one embodiment of the filter according to the invention, the inner filter stage in the form of the filter element 10 consists of a voluminous meltblown depth filter cartridge made of polypropylene. The filter fineness of the depth filter cartridge is preferably between 10 μL / m and 200 μm; alternatively, a sintered filter (not shown in detail) with the same filter fineness can also be used. To produce a depth filter cartridge from meltblown fibers, these are preferably sprayed onto the inner support body 20. The outer filter stage with the second filter medium 18 consists of a three-layer, pleated structure made of polypropylene fabric. The mesh size of the two outer layers facing the support body 22 is preferably approximately 200 to 1000 μm, which is relatively coarse. In contrast, the mesh size of the inner layer is between 0.1 and 500 μm, which can be described as relatively fine.The pleat density of the pleated filter mat, which forms the second filter medium 18, is 0.1 to 6 pleats per centimeter.

[0021] In addition to the aforementioned material polypropylene, other plastic materials that can be used in production include polyamide or polyester. If the same plastic material is used for the filter media 16, 18 as well as for the support bodies 20 and 22 and for the end caps 26, 28, a pure structure is achieved, which helps facilitate the recycling of the filter as a whole. Twill or satin weaves, as well as so-called smooth fabrics, can be used as weaves for the second filter medium 18. The use of other weaves is also possible here. In addition to the three-layer structure described, a structure with two to five layers is also possible, whereby the mesh size should preferably run from coarse to fine as seen in the flow direction 24.

[0022] For the previously mentioned mirror welding process, two identically designed centering rings 30, which are provided with through holes 32, are inserted into the flow chamber 14 in the area of ​​the upper end cap 26 and in the area of ​​the lower end cap 28. The upper centering ring 30, as viewed in the direction of Fig. 2, is fixed to the upper end cap 26 with its upper free end face by mirror welding, and the through holes 32 formed in the centering ring 30 allow rising gas bubbles to pass from the flow chamber 14 between the two filter media 16, 18. Likewise, the lower centering ring 30, as viewed in the direction of Fig. 2, is mirror welded to the lower end cap 28 with its lower free end face. For this purpose, the respective centering ring 30 has an annular securing rib 34 on its inner circumference and a similar annular securing rib 36 on its outer circumference.The respective webs 34, 36 accommodate, approximately centrally between them, a base section 38 of the respective centering ring 30, into which the through-holes 32 are introduced. The through-holes 32 extend at discrete distances from one another along the base section 38, which runs parallel to the alignment of the end caps 26, 28. Towards the outside, the respective securing web 34, 36 is supported on upper parts of the outer circumference of the first filter medium 16 and on the inner circumference of the second filter medium 18. For the sake of simplicity, the two centering rings 30 are designed identically, whereby the lower centering ring 30, as viewed in the direction of Figure 2, does not necessarily have to have the through-holes 32 for the removal of gas bubbles. In any case, the upper and lower free end faces of the two fixing webs 34, 36 of each centering ring 30 are also mirror-welded to the associated end cap 26 or 28.Instead of the aforementioned mirror welding, other welding methods can also be used, for example, transmission welding using laser light, as shown by way of example in the documents DE 10 2007 013 178 A1 and DE 10 2010 005 541 A1 of the patent holder. Ultrasonic welding methods can also be used; the creation of adhesive bonds is also conceivable. The two webs 34, 36 each have pairs of projecting centering webs 39 extending outwardly toward the filter media 16, 18, which can at least partially penetrate into the flexibly yielding filter media 16, 18 in order to facilitate or enable the positioning of the webs 34 for the welding process within the filter. The centering webs 39 are ring-shaped and are an integral part of the respective securing web 34, 36.

[0023] The lower end cap 28 has a downwardly projecting hollow cylindrical annular socket 40 with a sealing device 42 in the form of an O-ring, which is received in an outer circumferential groove of the annular socket 40. In this way, the filter as a whole can be secured in a container housing 43 according to Figures 8 and 9, sealed from the environment, and the gas-containing process fluid can be supplied via the hollow passage of the annular socket 40 to the central inner side 44 of the filter, which is designed as an inflow chamber and is surrounded closest to the support body 20 and the first filter medium 16. However, the sealing device 42 with O-ring can also be omitted to maintain a single-material structure and replaced by a clamp connection (not shown).From this inner side 44, the process fluid passes along the flow direction 24 after passing the first filter element 10 into the flow space 14 and from there via the second filter element 12 with the subsequent further support body 22 to the outer side 45 of the filter, which corresponds to the interior of the container housing 43 within the scope of a container receptacle for the respective filter and will be explained in more detail with reference to Figures 8 and 9.

[0024] The upper end cap 26 has outlet openings 46 coaxial with the alignment of the upper through-holes 32 in the centering ring 30, which, as shown in particular in Figure 4, open with one free end into the flow chamber 14 above the centering ring 30 and with their other free end into an annular gap 48, which, starting from the inside of the thus closed upper end cap 26, opens onto the outside 45 of the filter. To form the circumferential annular gap 48 (not shown), an upper cap region 50 is offset from a lower end cap region 52 of the upper end cap 26, forming a radially outwardly projecting shoulder. Instead of a common annular gap 48 for all outlet openings 46 in the cover area of ​​the end cap 26, however, each outlet opening 46 is preferably connected to the outside 45 of the filter via its own flow channel 49, as shown in particular in Figure 1.Furthermore, it has proven advantageous to make the respective flow channel 49 relatively narrow and the free diameter of the outlet openings 46 is selected to be smaller than the free diameter of the through holes 32 in the centering ring 30. In any case, gas bubbles rising in the flow space 14 thus reach the individual flow channels 49 of the upper end cap 26 via the through holes 32 in the upper centering ring 30 and via the outlet openings 46 in order to be able to discharge them from the process fluid and from the filter to the environment in the form of the filter outer side 45.

[0025] In the coaxial arrangement of two filter stages with a flow from the inside to the outside and with a flow from below via the annular nozzle 40, a pure construction of the filter media 16, 18 from metal materials, in particular from stainless steel or titanium, can be used instead of the previous media construction.

[0026] In this embodiment, the inner filter stage in the form of the first filter medium 16 is a three-layer, pleated structure made of stainless steel. This structure replaces the voluminous meltblown structure made of the polypropylene variant shown above. The mesh size of the two outer layers, viewed towards the flow chamber 14, is again relatively coarse, with values ​​between 200 and 1000 fjm. The mesh size of the subsequent inner layer, in contrast, is relatively fine, with values ​​between 0.1 and 500 fjm. In addition to stainless steel, titanium can also be used. The pleat density of the pleated filter material is 4 to 8 pleats per square centimeter, and weaves such as twill, satin, smooth weave, etc. are used. A structure with 2 to 5 layers is also conceivable; here, too, the mesh size should go from coarse to fine as viewed in the flow direction 24.Alternatively, sintered filters with similar degassing properties can be used.

[0027] The outer filter stage, in the form of the second filter medium 18, also consists of a three-layer, pleated stainless steel structure with comparable mesh sizes on the outside and inside, as stated above. The pleat density here is preferably 0.1 to 6 pleats per centimeter, and the weaves described above are also used. Coating the entire filter or just the individual fabrics 16, 18 can lead to a further improvement in the degassing properties, particularly if the coating is applied with coalescence-promoting materials. The materials used for the filter media 16, 18 can also be passivated in this way to prevent the release of electrons and iron ions. Regarding the functionality of a two-stage degassing filter with a purely metallic construction, this corresponds to the solution presented above.Instead of the welding processes presented, the metallic filter media 16, 18 can also be glued to the corresponding end caps 26, 28 or crimped together using a metallic joining technique (not shown). For an improved degassing process, it has proven advantageous to select a correspondingly high pleat density for the first filter medium 16 and a correspondingly low pleat density for the outer filter medium 18.

[0028] The second embodiment according to Figures 3, 6, and 7 will be explained below only insofar as it differs significantly from the embodiment described above. In particular, the same reference numerals as indicated above are used for the same components, and the statements made in this regard accordingly also apply to the further second embodiment. Instead of the centering ring 30 described above, a single circumferential positioning ring 54 is used for the second embodiment, which is supported with a predeterminable axial extent on the inner circumferential side of the second filter medium 18, specifically towards its free end regions.The respective positioning ring 54, in turn, has pairs of centering webs 39 on the outer circumference, which at least partially engage the inner circumference of the second filter medium 18, in order to ensure the positional fixation of the positioning ring 54 at the respective end region of the second filter medium 18. In this way, the mirror welding process can be effectively supported by means of the two positioning rings 54.

[0029] As Figure 7 shows in particular, the second filter element 12 with its outer support body 22 as well as the second filter medium 18 and the lower positioning ring 54 is connected, in particular welded, to an independent annular cap 56 which, in the installed position shown in Figure 7, is supported on the bottom side on a flange-like projection 58 of the lower end cap 28. In this way, the annular cap 56 rests on parts of the lower end cap 28 without any protrusion. For sealing, in the region of the step-like transition between the projection 58 and the rest of the lower end cap 28, a further sealing device 62 is introduced into a radially outwardly open annular groove 60 of the latter, which seals the interior of the filter from the environment in the form of the filter outer side 45.Just as the first sealing device 42 on the ring nozzle 40 can also be dispensed with, the further sealing device 62 can also be dispensed with if a clamp connection (not shown) is to be used at the respective connection point, which can be additionally secured by means of a welded or adhesive connection.

[0030] Accordingly, the bottom side of the outer support body 22 and the second filter medium 18, together with the lower positioning ring 54, are welded, in particular mirror-welded, to the top side of the ring cap 56. Furthermore, the underside of the inner support tube 20, together with the underside of the associated filter medium 16, is welded, in particular mirror-welded, to the top side of the actual lower end cap 28. Accordingly, the upper end of the outer support body 22, together with the associated second filter medium 18 and the upper positioning ring 54, is welded to the lower, flat end face of the upper end cap 26. In this embodiment, too, the outlet openings 46 in the upper end cap 26 open into the flow chamber 14.However, what differs from the previously described embodiments is that the first filter element 10 has its own end cap 64, which, in the form of a flat annular disc, leaves a gap-shaped passage 66 formed by the upper side of the end cap 64 and the adjacent underside of the upper end cap 26. Thus, the hollow-cylindrical flow chamber 14 is connected at its upper end via the passage 66 in a media-conducting manner. This also enables tolerance compensation between the two filter elements 16, 18. For the entire construction of the filter according to the second embodiment, the same materials as described above are used.The connection of the individual filter components to form a complete filter is particularly cost-effective using the materials mentioned and the aforementioned mirror welding process. Overall, due to the strong welded joints, the filter can be designed as an easily recyclable disposable product. Viewing the filters from the outside, as shown in Figures 2 and 3, the filter appears as shown in Figure 1.

[0031] As shown in Figures 8 and 9, a total of six filters are inserted into a container housing 43 as described above, with a cover part 68 that can be removed from the housing 43 for the purpose of removing used filters and replacing them with new elements. The cover part 68 is provided with a hold-down device 70 to hold the individual filters, consisting of the first and second filter elements 10, 12, in position. For this purpose, when the cover part 68 is closed, the hold-down device 70 presses the individual filters from above via the respective annular connector 40 onto a separating or adapter plate 72 with correspondingly designed annular recesses 74.The container housing 43 or the container itself further comprises an inlet 76 for gas-containing process fluid on the bottom side, as well as an outlet 78 for the gas separated in the container 43 and a further outlet 80 for the process fluid freed from the gas. Flow through the respective filter, starting from the inlet 76 of the container 43, flows from the inside to the outside. The separated gas is passed above a fluid level 82 in the container 43 to one outlet 78 in the container 43. Process fluid accumulated below this fluid level 82 in the container 43, however, exits the container 43 via the further outlet 80.

[0032] For a parallel flow to the respective filter from below via the openings in the form of the annular recesses 74 in the adapter or separating plate 72 in the container 43, the filter is vertically aligned as shown in Figure 8. In particular, the respective filter is guided upwards above the fluid level 82 and extends between the separating or adapter plate 72 and the hold-down device 70. For improved removal of the process fluid or process water, a suction connection 84 is provided between the individual filters, which opens laterally above the separating or adapter plate 72 and below the fluid level 82 in the container 43 and is thus connected to the further outlet 80 for the process fluid. In this way, it is easily possible to accommodate 3 to 30 degassing filters in a tank in the form of the container 43. The number of filters used can be selected depending on the volume flow to be treated.What is important is the parallel flow to the degassing filters from below via the separating or adapter plate 72. The container 43 or the container housing is preferably made of stainless steel and has an inner coating for passivation and corrosion protection.

[0033] The gas bubbles separated by the first filter medium 16 and the second filter medium 18 through coalescence and buoyancy-induced separation pass through the flow chamber 14 from the process fluid side to the gas side, which is located above the fluid level 82 in the container 43. The gas collected in the flow chamber 14 then passes, as already explained, via the channel guides in the upper end cap 26, which are arranged above the fluid level 82, to the gas discharge side of the container 43 with the gas connection 78. Overall, a sequential flow through the two filter stages in the form of the first filter element 10 and the second filter element 12 with associated filter media 16, 18 takes place with gas-containing process fluid. The first filter stage in the form of the first filter element 10 then leads to a first coalescence or pre-separation of the gas bubbles (air / hydrogen / oxygen).The retained gas bubbles coalesce and rise upwards, as do the enlarged gas bubbles after flowing through the filter stages 10, 12 in the annular gap between the first stage 10 and the second stage 12 formed by the flow space 14. After passing through the indicated degassing openings in the upper end cap 26, the gas bubbles reach the fluid surface, i.e., the fluid level region 82, which varies in height, as shown in Figure 8. The air bubbles not yet separated are retained by the outer second degassing stage in the form of the second filter element 12, coalesce to this extent, and then also rise upwards due to buoyancy, above the fluid level 82. The filter arrangement mentioned, using appropriate container geometries, can be used for any degassing process for process fluids and is not restricted to process water, such as that produced during hydrogen electrolysis.

Claims

Patent claims Filter for the treatment of process fluid, as it arises in particular during hydrogen electrolysis, preferably for separating hydrogen and / or oxygen from process water, with a first filter element (10) and with a second filter element (12) which surrounds the first filter element (10) to form a flow space (14) with a predeterminable radial distance, wherein each filter element (10, 12) has a filter medium (16, 18) through which the process fluid can flow from the outside in or preferably from the inside out in a flow direction (24), wherein, viewed in the flow direction (24), one filter medium (16) forms a first degassing stage which serves to enlarge gas bubbles by coalescence and to remove them from the process fluid by buoyancy-induced separation, and the subsequent further filter medium (18) forms a second degassing stage,which serves to remove finely distributed gas bubbles remaining in the process fluid by coalescence and to separate them by buoyancy-induced ascent. Filter according to claim 1, characterized in that the one filter medium (16) preceding in the flow direction (24) consists of a depth filter candle, which is designed as a hollow cylindrical filter shell to increase the filter volume. Filter according to claim 2, characterized in that meltblown fibers are used to form the depth filter candle, which are preferably sprayed onto a fluid-permeable support body (20) against which the filter shell is supported along its inner circumferential side.

4. Filter according to claim 3, characterized in that the depth filter candle is constructed from a sintered material.

5. Filter according to one of claims 2 to 4, characterized in that the filter fineness of the depth filter candle constructed from meltblown fibers is between 10 fjm and 200 fjm, the fiber diameter is between 0.1 fjm and 2,000 fjm, and the average flow-effective pore diameter is between 1 fjm and 2,000 ji / m.

6. Filter according to one of claims 1 to 5, characterized in that for a pure construction all components of the filter, such as filter media (16, 18), end caps (26, 28) and support bodies (20, 22) consist of one and the same plastic material, preferably of polypropylene.

7. Filter according to one of the preceding claims, characterized in that the filter medium (18) following the one filter medium (16) in the flow direction has at least a two-layer, preferably a three-layer mat structure.

8. Filter according to claim 1, characterized in that for a pure construction the respective filter medium is constructed to form a two-stage degassing filter from metals, such as stainless steel or titanium, and that the respective filter medium (16, 18) of at least one filter element (10, 12) has at least a two-layer, preferably three-layer, pleated mat structure made of metal threads or metal fibers, preferably is constructed entirely from stainless steel materials.

9. Device with a container (43) for receiving at least one filter according to one of the preceding claims, which has at least one inlet (76) for gas-containing process fluid and an outlet (78) for the gas separated in the container (43) and a further outlet (80) for the process fluid freed from the gas, wherein the respective filter flows from the inside to the outside starting from the inlet (76) of the container (43), above a fluid level (82) in the container (43) the separated gas is passed on to the one outlet (78) in the container (43) and below this fluid level (82) process fluid collected in the container (43) is discharged from the container (43) via the further outlet (80).Container according to claim 9, characterized in that a parallel flow to the respective filter from below via openings (74) in a partition plate (72) in the container (43) which extends parallel to the fluid level (82) and that a suction connection (84) is provided between the individual filters, which opens out above the partition plate (72) and below the fluid level (82) in the container (43) and is connected to the further outlet (80) for the process fluid.

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