Filter Device

Abstract

A filter device consisting of a combination of various filter elements 10, 12 combined to form a structural unit, one filter element 10 of the various filter elements serving to clean particles and the other filter element 12 serving to clean oil oxidation products from the fluid stream, the filter elements 10, 12 being connected in parallel with each other to clean the fluid stream.

Description

[Technical field]

[0001] The present invention relates to a filter device, freely available on the market in several embodiments. Such a filter device is used to remove particle contamination by means of the filter material of a filter element, to purify a contaminated fluid, for example in the form of a hydraulic working medium, which is fed to a filter housing, and to return the thus purified fluid from the filter housing to a fluid circuit, in particular a hydraulic circuit. When the filter material becomes clogged with dirt after several filter cycles, it is used up and the filter element must be removed from the device housing and replaced with a new element for continued operation. [Background technology]

[0002] Patent document 1 (EP 3334512) describes an oil filtration unit for removing solid particles from contaminated oil, a housing including a housing inlet adapted to receive contaminated oil from the environment and discharge the contaminated oil at a first pressure p1 into an internal opening of the housing, and a housing outlet adapted to discharge filtered oil to the environment; an oil filter for filtering contaminated oil, the oil filter comprising: a filter inlet disposed within the inner opening of the housing and defined by an outer surface of the oil filter; an inner filter volume adapted to receive filtered oil at a second pressure p2 lower than the first pressure p1; and a filter outlet providing a fluid / liquid connection between the inner filter volume and the housing outlet for draining filtered oil from the inner filter volume; an end plate of the oil filter surrounding the filter outlet, the entire end plate comprising a porous material through which oil can flow, such that at least a portion of the end plate forms a portion of the filter outlet; the filter outlet includes a hydraulic resistor forming part of the oil filter; The hydraulic resistor discloses an oil filtration unit that provides a fluid flow restriction between the internal filter volume and the housing outlet to increase a second pressure p2 in the internal filter volume and discharge filtered oil from the internal filter volume to the housing outlet at a third pressure p3 lower than the second pressure p2.

[0003] Furthermore, DE 102005014360 A1 discloses a filter element having a filter material with individual filter folds folded in a star shape, in which at least one fluid-permeable support means extends at least partially in the gap between two adjacent filter folds and / or on the inner and / or outer circumference of the filter folds, this support means comprising or being itself constructed from a filter active material. In this way, a kind of filter aid is obtained, which helps to reduce the effect of fluid components that reduce the service life, whether in the form of certain oil oxidation products, also known technically as varnish, or in the form of other media that damage the fluid. In the known filter element arrangements, the fluid is always made to flow successively through the filter material and the fluid-permeable support medium. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] European Patent No. 3334512 [Patent Document 2] DE 102005014360 [Patent Document 3] International Publication No. 2018 / 082799 Summary of the Invention [Problem to be solved by the invention]

[0005] Based on this prior art, the object of the present invention is to improve the known filter device solution. [Means for solving the problem]

[0006] This problem is solved by a filter device overall having the features of claim 1.

[0007] The filter device according to the invention consists of a combination of various filter elements combined to form a structural unit, one of which serves to clean particles or solid pollutants and the other to clean oil oxidation products (varnish) from the fluid flow, which are connected in parallel with each other to clean the fluid flow. This allows the fluid flow to be divided and in each case the respective filter element to be controlled with a special cleaning option with a predefined division ratio. In this way, the fluid flow can be treated particularly efficiently. Such a filter device is essentially part of a hydraulic supply circuit, and the fluid already treated by the structural unit can be fed back to the filter device as part of the circulation process. Moreover, oil oxidation products or varnishes are not regularly listed in the literature as "hard" particles, so that they do not represent particulate contamination in the true sense of the word, rather they are usually a type of slurry-like contamination of the fluid flow.

[0008] Preferably, the filter elements are arranged one above the other to form a structural unit, with each element material separating the unfiltered side from the filtered side surrounded by the respective element material, in this way it is possible to achieve a continuous flow along the entire periphery side of the structural unit and with the fluid being treated in the same way over the entire surface of the filter elements.

[0009] In a particularly preferred embodiment of the filter device according to the invention, the filter element for particle cleaning has a pleated, preferably multi-layered, element material, and the filter element for receiving the oil oxidation products is formed by individual annular disks arranged one above the other, which consist at least partially of cellulose, preferably completely of cellulose. Due to the folding of the element material, the surface area of ​​the filter element is correspondingly increased, so that solid particles can be cleaned to a high degree from the fluid flow. Whereas in the prior art cellulose filter elements are mainly used for particle cleaning (EP 3334512) or even for separating water from oil fluid flows (WO 2018 / 082799), in the present invention the annular cellulose-containing discs are used for cleaning oil oxidation products (varnish), whereby when the fluid flows through the cellulose fibers as in the prior art, it still has a coalescence effect, whereby enlarged droplets of oil-containing emulsion are formed from the water part, which sink downwards due to the density difference between water and oil, so that the less dense medium is also separated and thus the water is separated from the hydraulic working medium.

[0010] In a further preferred embodiment of the filter device according to the invention, the structural unit formed by a number of filter elements in each case has an end cap at each end, one of which seals at the bottom a filter element for particle cleaning and the other end cap seals at the top a filter for cleaning oil oxidation products and is provided with through holes for the filtered flow. In this way, the structural unit as a whole is a replacement product, which can be replaced by a new unused structural unit as part of the entire complete device when the filter element material is exhausted.

[0011] In a particularly preferred embodiment of the filter device according to the invention, at least one throttle or orifice point is present on the filtration side of the structural unit, which divides the fluid volume flow rate between the individual filter elements in a predetermined ratio. Since cellulose materials often form a denser cleaning medium than pleated filter element materials, the flow resistance of the cellulose elements is increased so that, for simultaneous uniform flow through the structural unit on the filtration side, the throttle or orifice point is arranged on the filtration side, preferably at the fluid outlet of the filter element for particle filtration and at the adjacent inlet of the filter element for cleaning oil oxidation products. In this way, the flow resistance at the outlet of the particle filter element can be increased in the direction of the filtration discharge side of the particle filter, so that a uniform fluid flow is achieved for both filter elements arranged above and below.

[0012] This restriction or orifice point is preferably located in an intermediate cap between one filter element and the other, in order to save space.

[0013] In a further preferred embodiment of the filter device according to the invention, all filter discs with cellulose material have the same filter properties, in particular the same filter grade, and the annular filter discs are all constructed identically with respect to their component material. In this way, a type of stack structure or stack sequence is achieved, in which the filter discs can be stacked one on top of the other in a predetermined number of identical components depending on the respective filtering task, in order to obtain a varnish element of a predetermined height.

[0014] To ensure improved flow with low turbulence, the individual annular filter discs have recesses at their periphery, formed by cuts, indentations or adjacent spacers between the filter discs.

[0015] The above-mentioned cellulose filter discs are produced in accordance with DIN EN ISO 5269-2 using the so-called rapid Köthen process, which is a standardized process so that a high level of process reliability is achieved during production.

[0016] In the following, the filter device according to the invention will be explained in more detail using embodiments according to the drawings, in which: Figure 1 shows a filter device according to the invention; [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 shows the entire filter device in longitudinal section. [Diagram 2] FIG. 2 is a side view of a modified example of the filter device shown in FIG. [Diagram 3] FIG. 3 shows a perspective view of a further variant embodiment of the filter device according to FIGS. [Figure 4] Figure 4 shows in the form of a hydraulic circuit diagram the basic parallel connection of the filter devices according to Figures 1 to 3, integrated into a simplified hydraulic supply circuit with a motor-pump unit and a storage tank. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Fig. 1 shows the filter device as a whole, which forms a structural unit and represents the assembled combination of two different filter elements 10, 12, of which one filter element 10 serves mainly to clean particles and the other filter element 12 serves mainly to clean oil oxidation products (varnish) from the fluid flow, the fluid guides are shown in Fig. 1 as lines and the arrows show the flow direction, whereby the flow circulates from the outside to the inside throughout the filter device. By the shown arrows and lines it is also clear that the two filter elements 10, 12 are connected in parallel with each other to clean the fluid flow. The fluid to be cleaned can consist of a hydraulic working medium or a hydraulic oil, but also of another fluid accessible to the cleaning process mentioned here.

[0019] The filter arrangement shown in FIG. 1 consists of only two filter elements 10, 12, but within the scope of the solution of the arrangement according to the invention it is possible to choose different arrangements with further filter elements (not shown).

[0020] 1 shows the filter arrangement and the normal operating position of the filter elements 10, 12, which form a structural unit by being stacked one on top of the other and which separate the so-called unfiltered side 18 from the filtered side 20, which is surrounded by the respective hollow-tubular element material 14, 16, by the respective element material 14, 16. In the configuration shown in FIG. 1, the further filter element 12 is arranged above the first filter element 10, and in principle it is also possible to rotate this configuration if necessary (not shown). However, the illustrated configuration is particularly advantageous with regard to the flow behavior of the fluids, which will be explained in more detail below.

[0021] The particle cleaning filter element 10 comprises a pleated, preferably multi-layered element material 14. Such an element material 14 or multi-layered filter medium may have, for example, the following layer structure from one side to the other: 1.Mesh structure, metal wire mesh, synthetic fiber or plastic mesh 2. Polyester fleece, 3. Fiberglass mat or meltblown fleece 4. Paper fleece, glass fiber mat or meltblown fleece 5. Polyester fleece 6. Stainless steel-polyester mixed fabric, with mesh structure, metal wire mesh or synthetic fiber or plastic mesh

[0022] At this point, it should be emphasized that this layer structure is merely an example, but has proven to be particularly effective for particle filtration. However, there is also the possibility of using a different structure, in which case it is particularly advantageous to place a pre-filter layer upstream of the main filter layer in the direction of fluid flow. It is also advantageous to form the individual filter folds with different fold heights, with the folds of a lower fold height preferably being inserted between the folds of a higher fold height, in order to provide a support function for the individual filter folds. Furthermore, the star-folded filter layer in the form of the element material 14 can be supported in the usual way on a hollow cylindrical perforated support tube 22.

[0023] The filter element 12 for collecting oil oxidation products or varnish, respectively, consists of individual annular discs 24 which, when arranged one above the other, form a stack or a laminated sequence, the individual annular discs consisting at least partly of cellulose, preferably entirely of cellulose material.

[0024] As shown in particular in Fig. 1, the individual filter discs 24 can in one embodiment also be formed by part halves 24a, 24b which between them, viewed in the diametric direction relative to the longitudinal axis of the structural unit, have a number of recesses 26 of the same shape facing each other, which recesses are formed by notch-like cuts or indentations in the filter disc 24 or by two filter disc halves 24a, 24b of the respective filter disc 24 arranged adjacent to each other. Furthermore, further recesses 28, which are configured correspondingly to the recesses 26, are located in the stacking sequence between the filter discs 24. Each recess 26, 28 thus extends from a rectangular central area tapering at the edges into the respective filter disc 24 or into the adjacent disc half 24a, 24b. The aforementioned recesses 26, 28 in the form of cuts or impressions are arranged only on the upper side of the respective element material 16 and do not engage the hollow cylindrical inner chamber 30 of the filter element 12, which also forms the filtering side 20 of the filter arrangement, as shown in particular in FIG.

[0025] In the variant embodiment according to Fig. 2, the recesses 26, 28 are formed by corresponding circumferential indentations or cuts, which in each case serve to reinforce the stability of the cellulose element as a whole and to improve the flow guidance for the flow of unfiltered material from the exterior of the filter element 12 to the inner chamber 30. In each case, on each filter disc or between the disc halves 24a, 24b of the filter disc 24, there are four recesses 26, 28 located in a common radial plane. In particular, the disc-shaped element material 16, which is configured to be closed up to its porous area, is formed by a filter blank originating from a sheet former. In the embodiment according to Fig. 3, the individual filter discs 24 which together form the individual disc halves 24a, 24b, have a number of radially extending limiting rods facing each other as spacers 32, which define recesses 34 between them, which serve to improve the channel-like fluid guidance, but which again do not completely penetrate the filter element material 16 comparable to the recesses 26, 28 according to the previous embodiment. The multiple disks 24 arranged one on top of the other in this manner serve to clean oil oxidation products from the fluid stream as indicated by the arrowed lines in Figure 1. At this point, there is a simultaneous flow through both filter elements 10, 12 from the unfiltered side 18 to the filtered side 20.

[0026] As further shown in FIG. 1, the disk 24 arranged at the bottom, as viewed in the direction of the drawing, is only a half-body provided in the form of a partial half-body 24a. As can be seen from FIGS. 1-3, the structural unit formed by the filter elements 10, 12 in each case has end caps 36, 38 at each end, of which one end cap 36 seals the filter element 10 for particle cleaning at the bottom and the other end cap 38 seals the filter element 12 for cleaning oil oxidation products at the top and is provided with a through hole 40 for draining the filtered flow from the filter device. According to the illustration in FIG. 1, the lower bottom cap 36 can be provided with a flow guider 42 for improving the flow guidance, which protrudes into the filtering side 20 of the filter element 10. In this case, the flow guider 42 is formed by a solid block, which is provided with a boundary surface 44 at its end face, which emerges at its edge into a convex peripheral edge 46 that runs across the longitudinal axis of the filter device and is defined from the outside by the support tube 22. The height of the flow guider 42 is preferably 1 / 5 to 1 / 4 of the total height of the filter element 10 for particle cleaning.

[0027] As can also be seen from Fig. 1, a throttle or orifice point 48 is provided in the middle of the filtering side 20 of the structural unit, which divides the fluid volume flow rate between the adjacent individual filter elements 10, 12 in a predetermined ratio depending on the selected free cross-sectional area. The throttle or orifice point 48 is arranged in an intermediate cap 50 between one filter element 10 and the other filter element 12. In particular, the throttle or orifice point 48 is arranged at the fluid outlet 52 of the filter element 10 for particle filtration and at the corresponding adjacent inlet 54 of the filter element 12 for cleaning oil oxidation products, and thus at the filtering side 20.

[0028] In Fig. 4 the basic function of the throttle or orifice point 48 is shown in more detail by means of a hydraulic supply circuit with a motor pump unit 56. This motor pump unit 56 takes hydraulic fluid from a storage tank 58 and, as part of the above-mentioned parallel connection, supplies both filter elements 10, 12 with fluid equally, and as already explained, the throttle or orifice point 48 is arranged at the outlet 52 of the filter element 10 for particle contamination, seen in the direction of fluid flow. With regard to the parallel connection referred to here, the throttle of the fluid flow at the outlet 52 of the filter element 10 affects the fluid supply at the inlet 54 of the filter element 12. In the simplified representation according to Fig. 4 the filtered flow then flows back to the storage tank 58 at the filtered discharge side of both filter elements 10, 12, but in reality hydraulic components such as hydraulic actuating cylinders, valve devices, hydraulic accumulators, etc. are generally connected to the filtered side 20 of the filter device, which require purified fluid from the filter device for proper operation. Total resistance R ges is as follows:

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Claims

1. A filter device consisting of a combination of various filter elements (10, 12) combined to form a structural unit, One filter element (10) of said various filter elements (10, 12) serves to clean particles and the other filter element (12) serves to clean oil oxidation products from the fluid stream; A filter device, wherein the various filter elements (10, 12) are mounted in parallel with one another for cleaning the respective fluid flows.

2. 2. The filter device according to claim 1, wherein the various filter elements in a stacked arrangement form the structural unit, and the respective element materials (14, 16) of the various filter elements separate an unfiltered side (18) from a filtered side (20) surrounded by the respective element materials (14, 16).

3. The filter element (10) comprises a pleated, preferably multi-layered element material (14) for particle cleaning, 2. A filter device according to claim 1, characterized in that the filter element (12) is formed by individual annular filter discs (24) arranged one above the other to receive the oil oxidation products, the annular filter discs (24) consisting at least partly of cellulose, preferably entirely of cellulose.

4. the structural units formed by the filter elements (10, 12) are in each case provided with end caps (36, 38) at each end, One of the end caps (36) seals the filter element (10) at the bottom for particle cleaning; 2. The filter device of claim 1, wherein the other end cap (38) seals the filter element (12) for cleaning away the oil oxidation products and has through holes (40) for filtered flow.

5. 2. The filter device according to claim 1, characterized in that there is at least one throttle or orifice point (48) on the filtering side (20) of the structural unit, which divides the fluid volume flow between the various individual filter elements (10, 12) in a predetermined ratio.

6. 2. The filter device according to claim 1, characterized in that a throttle or orifice point (48) is arranged at a fluid outlet (52) of the filter element (10) for particle filtration and at an adjacent inlet (54) of the filter element (12) for removing oil oxidation products on the filtration side (20).

7. 2. A filter device according to claim 1, characterized in that a throttle or orifice point (48) is arranged in an intermediate cap (50) between the one filter element (10) and the other filter element (12).

8. 4. A filter device according to claim 3, characterized in that all filter discs (24) made of cellulose material have the same filtering properties, in particular the same filter fineness, and the annular filter discs (24) are all constructed identically with respect to their component materials.

9. 4. The filter device according to claim 3, wherein each of the annular filter discs (24) has a recess (26, 28, 34) on its outer periphery formed by a cut, an indentation, or an adjacent spacer (32) between the annular filter discs (24).

10. 3. A filter device according to claim 2, characterized in that the closed disc-shaped element of material (16) is formed by a filter blank, preferably made of sheet material.

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