Filter Device

Abstract

A filter device comprising a filter housing (1) having a cover member (2) and accommodating a replaceable filter element (7), wherein an element member (9) of the filter element (7) extends between two end caps (13, 14) of the filter element (7), characterized in that the filter housing (1) is configured as an outlet pipe (3) and extends between the two end caps (13, 14).

Description

[Technical field]

[0001] The present invention relates to a filter device comprising a filter housing containing a replaceable filter element and having a cover member, the cover member of the filter element extending between two end caps of the filter element. [Background technology]

[0002] Filter devices of this type are known in the prior art in various embodiments with replaceable filter elements corresponding to different specifications. In this type of filter device, the filter elements are used for the maintenance of the fluid, in particular in hydraulic systems. As shown in DE 10 200 03 133 A1, which discloses a filter device of the type mentioned at the beginning, such a filter device can advantageously be used as a so-called in-tank filter device. In the known solution, the filter housing with the filter head and the adjoining filter pot extends vertically into the interior of the tank. The filter pot has the form of a relatively thin-walled cylinder and is fixed to the filter head by flange molding. The length of the filter pot is dimensioned in such a way that the lower end of the filter housing is below the expected fluid level in the tank during operation, e.g. hydraulic oil. During filtering operation, the fluid passes from the flow channel in the bottom region of the tank through the lower end cap to the interior of the filter element and, after passing through the element member, flows out of the filter element as filtrate, with the filter pot forming an outlet pipe which has holes or window openings through which the filtrate can reach the interior of the tank. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] German Patent Application Publication No. 102015003604(A1) Summary of the Invention [Problem to be solved by the invention]

[0004] The object of the present invention is to proceed from this prior art and to provide a filter device of the type mentioned at the outset which is characterised by a particularly simple and cost-effective construction. [Means for solving the problem]

[0005] According to the invention, the above object is achieved by a filter device having in its entirety the features of patent claim 1.

[0006] According to the characterizing part of claim 1, an essential feature of the invention is that the filter housing is configured as an outlet pipe and extends between the two end caps. Due to the fact that the outlet pipe is integrated in the filter element, the entire filter housing extending from the cover into the tank consists of the filter element alone. This eliminates the need for a part of the filter housing in the tank and a filter pot forming an outlet pipe connected to the filter head, as in the prior art. Since the inventive integration of the outlet pipe in the filter element also eliminates the need for a filter head, the filter arrangement according to the invention can be manufactured with a very simplified construction and correspondingly low costs. A further particular advantage is that the outlet pipe as an integral part of the filter element does not form a permanent part of the filter arrangement, but is replaced together with it when the filter element is replaced. The outlet pipe, as a part that does not have to function reliably over the entire service life of the filter arrangement, can therefore be manufactured from simple and inexpensive materials of lightweight construction.

[0007] Advantageously, a slot-shaped annular guide space is provided in each end cap to form a receiving section for the assigned end of the outflow pipe, which can be arranged to engage at least partially on the inner and outer circumferential sides with the wall of the outflow pipe, the received end being fixed in the slot guide by means of an adhesive.

[0008] Advantageously, the annular guide space in the end cap, preferably the end cap assigned to the lid element, allows axial play for the assigned end of the outlet pipe. In this way, the risk of compression of the outlet pipe is avoided if the length between the end caps deviates from the desired value. Therefore, when manufacturing the filter element, tight manufacturing tolerances do not have to be observed for critical components such as the support tube. Thus, in particular in the case of relatively long filter elements with, for example, a support tube assembled from partial segments, the manufacturing is simpler and less expensive, since the tolerances to be observed are not so tight.

[0009] In a particularly advantageous embodiment, the support tube, which runs between the end caps on the outside of the element member, has a support structure consisting of longitudinal and transverse beams which leave the fluid passages free and at least the longitudinal beams are aligned parallel to the longitudinal axis of the filter element to support the element member on the inner circumference and to form a gap between the element member and the outlet pipe as a spacer. If a guide for the outlet pipe is formed in this way, the outlet pipe can be formed very inexpensively, for example from a plastic film.

[0010] The support tube consists of individual part segments arranged one behind the other and latchable to one another by latching means, the two outer part segments having towards their free outer ends respectively latching means for latching with an assignable end cap. In this way, in the case of filter elements of various lengths, the support tube can be produced injection-molded from plastic without the need for separate moulds for each length. As shown in DE 19826032 A, the desired overall length can be realised by assembling the part segments in the manner of a modular system of two or more part segments, each having a prefabricated length.

[0011] In an advantageous embodiment, the end cap assigned to the lid is latched to the lid on its inner side by means of a latch bar, so that the assembly work for installing the filter device in the tank is limited to attaching the lid as a tank plug to the tank opening in question.

[0012] Advantageously, the outflow tube can be formed with a single layer or multiple layers and with channels. A two-layer structure can improve the outflow behavior of the liquid, thereby facilitating the degassing of air from the fluid. The layers can be various combinations of perforated sheets, fabrics or grids, the choice of which depends on the properties of the fluid in question.

[0013] In a preferred embodiment, non-filtrate is fed to the inside of the filter element through a lower end cap facing away from the lid member, and filtrate is discharged through the outside of the filter element towards an outlet tube.

[0014] In an advantageous embodiment, a bypass valve is integrated in the lid, which in the open state forms a flow path leading to the interior of the lid through an opening in an end cap assigned to the lid, the end cap having a passage near its periphery which opens into the gap on the inside of the outlet pipe, so that the volume flow possible when the bypass valve is open also reaches from the upper side of the end cap into the gap forming the filtrate side and thus through the outlet pipe to the tank interior.

[0015] The present invention will now be described in detail with reference to the drawings. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a perspective view of one embodiment of a filter device according to the present invention. [Diagram 2] FIG. 2 is a perspective view of an embodiment in which a cover member is omitted, cut along a central vertical section. [Diagram 3]FIG. 3 is an enlarged, cut-away perspective view of only the upper end region of the embodiment adjacent to the lid member, cut along a central vertical plane. [Figure 4] FIG. 4 is a perspective view of only the upper end region of the filter device of the embodiment, cut along a central vertical section, and further enlarged compared to FIG. [Diagram 5] FIG. 5 is a view corresponding to FIG. 4, showing only the lower end region of an embodiment of a filter element installed in a flow passage. [Figure 6] FIG. 6 is a perspective view of a filter element with the outlet tube partially cut away. [Figure 7] FIG. 7 is a perspective view of a longitudinal portion of an embodiment of a support tube constructed from partial segments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] In FIG. 1, where an embodiment of the filter device according to the invention is shown as a whole in the form of an in-tank filter device, a filter housing is indicated at 1, which is formed from a cover element 2 and an outlet tube 3. The outlet tube 3 has fluid passages in the form of windows 5 (only some of which are numbered) or holes 6, as shown in FIGS. 4 and 6. FIGS. 2 and 6 show a part of the filter housing 1, which extends from the cover element 2 (omitted in FIGS. 2 and 6) to the interior of the tank (not shown) and which consists of a constructional unit formed from the filter element 7 and the outlet tube 3 which is an integral part thereof. The filter element 7 has a hollow cylindrical element part 9 which extends with a support tube 11 between an upper end cap 13 and a lower end cap 14 as is customary. The upper end cap 13 assigned to the cover element 2 can be latched to the inner surface of the cover element 2, as will be explained in detail below with reference to FIGS. 2 to 4. As shown in FIG. 3, the lid 2 has a slightly convexly curved upper surface 15 and a trough-shaped inner chamber 17, the bottom of which 19 has a concave curvature corresponding to the curvature of the upper surface 15. The inner chamber 17 is bounded at its outer periphery by an axially projecting cylindrical side wall 21. The side wall 21 has an external thread 23 by means of which the lid 2 can be screwed onto a fixing flange 25 (FIG. 3) at the tank opening of the tank (not shown). The device for latching the end cap 13 to the lid 2 comprises three latch bars 28 projecting upward from the upper surface 27, which are arranged near the outer periphery of the upper surface 27 at an offset of 120° from each other, although not all of them are visible in the figure. The latch bars 28 each have the form of a cylindrical section coaxial with the longitudinal axis of the device, bent at right angles in the axial direction, and merge into a radially outwardly offset wall 30 with an end piece 31 at its upper end. As shown in FIG. 3, a holder 32 is provided which is assigned to the latch bar 28 and which is connected to the bottom 19 in the inner chamber 17 of the lid part 2 .These retainers 32 have coaxial inner guide links into which the latch bar 28 can enter by relative rotational movement between the end cap 13 and the closure member 2, so that the stepped surfaces 26 and 29 form a type of bayonet lock to lock the end cap 13 to the closure member 2 by form-fitting.

[0018] FIG. 5 shows the configuration of the lower end cap 14, through which the nonfiltrate reaches the inner filter cavity 35 for the filter operation. The end cap 14 has a central opening 56 for the nonfiltrate to enter the inner filter cavity 35. For the supply of nonfiltrate, a channel in the form of a pipe socket 58 is provided in the bottom region of the tank (not shown), which is fixed in place and which, in the functional position, projects into the opening 56 to form a fluid path into the filter cavity 35. The lower end cap 14 has a flat abutment surface 62 on the upper side as a frame for the facing ends of the element member 9 and the support tube 11, which is bounded on the radially outer side by a peripheral edge 64 which projects axially upwards. The peripheral edge 64 has an inner latch notch 65 into which a latch projection 68 of the support tube 11 engages, thereby axially fixing the support tube 11 to the end cap 14. The abutment surface 62 has a planar section extending radially inwards at the periphery 64, which is followed at the radially inner end by a stepped deepening recess 70, forming a transition to the opening 56. At the end of the central opening 56 offset axially downwards from the recess 70, the end cap 14 forms a molded all-around sealing lip 72, which has the shape of a thin tongue in cross section, opens obliquely downwards from the wall of the opening 56 and then extends obliquely upwards towards the filter element 7. The sealing lip 72 is elastically flexible depending on the elastic properties of the plastic material forming the end cap 32 and therefore seals tightly against the outside of the pipe socket 58. The end cap 14 forms a deepened groove 4 in the circumferential area extending radially outwards at the periphery 64, into which a slot-like annular space 80 is formed between the outer circumferential edge 76 and the inner annular body 78, into which the outflow pipe 3 is inserted and received. The outflow pipe 3 can be fixed in the annular space 80 by gluing. On its underside, the end cap 14 extends downwardly from the recess 70 in a tubular section 82, at the end of which a sealing lip 72 is formed.The section 82 together with the guide sleeve 84 forms a guide for the pipe socket 58, which extends through the opening 56 of the end cap 14 into the inner filter cavity 35 when the filter element 7 is fitted. The guide sleeve 84 has an annular flange 88 projecting radially outward above its lower end 86, which is received in the opening 56 of the end cap 14 so that the annular flange 88 fits into the recess 70. The other upper end of the guide sleeve 84 has an inwardly curved edge 90 which forms a stop for the upper edge 60 of the pipe socket 58 and thereby forms an end stop which limits the insertion movement of the pipe socket 58 when the filter element 7 is inserted. To form an insertion aid when the filter element 7 is fitted, the end cap 14 has, as a guide device following the lower end of the opening 56, a rim of shaped guide projections 92 which are distributed in the circumferential direction and project downwards in the shape of wings. The guide projections 92 form a guide surface 94 with their radially inner edge which extends conically upwards and inwards. In this way, the guide surfaces 94 together define a kind of insertion funnel which facilitates mounting of the filter element 7 in the pipe socket 58 .

[0019] Just as the lower end cap 14 has a slot guide for the lower end of the outflow tube 3 through the annular space 80, the upper end cap 13 also has an annular space 37 between the outer peripheral edge 39 of the end cap 13 and an annular body 41 protruding axially from the underside of the end cap 13 as an annular guide space into which the upper end 38 of the outflow tube 3 can be inserted. Further radially inward, a wall portion 43 protruding coaxially downward from the underside of the end cap 13 forms a frame for the upper end of the element member 9 and the upper end of the support tube 11. As in the case of the lower end cap 14, the wall portion 43 is provided with a latch notch 45 for latching the support tube 11, and the support tube 11 is provided with a latch protrusion 47 for latching the support tube 11 to the end cap 13.

[0020] As can be seen most clearly in Figures 6 and 7, the support tube 11 is assembled as a lattice-like support structure from three partial segments 49. These partial segments 49 are formed by the same part, injection-molded from plastic, and can be connected to each other by latching means. Each of the outer partial segments 49, which can be latched with the end caps 13, 14, has two latch tongues 51 arranged diametrically with respect to each other on the outer periphery, and are formed with latch projections 47 projecting radially outward, by means of which the upper end of the support tube 11 can be latched with the end caps 13, 14 (see Figures 3 and 4). As can be seen most clearly in Figure 7, the lattice structure is made up of ring-shaped elements 53, which form cross beams and extend at equal intervals from each other in the radial plane, and longitudinal beams connecting the ring-shaped elements 53. The longitudinal beams are formed by parallel flat strips 55 (again not all p numbered) which extend at equal intervals from each other and extend radially like wings from the ring-shaped elements 53. The flat strips 55 have their outer edges forming guide surfaces for the abutting outlet pipe 3 and, because they project radially from the ring-shaped element 53, act as spacers, forming a gap 57 between the element element 9 and the surrounding outlet pipe 3. During filter operation, when the fluid flows from the inner filter cavity 35 through the element element 9 to the outside, this gap forms the filtrate side from which it flows through the passage of the outlet pipe 3 into the tank interior.

[0021] The upper end cap 13 has a central opening 61 providing a possible passage from the filter cavity 35 to the interior chamber 17 of the lid member 2, which is normally closed by a closure body 63 of a bypass valve in the interior chamber 17 of the lid member. The bypass valve has a guide sleeve 67 projecting coaxially from the bottom 19 of the lid member 2, in which a shaft 69 of the closure body 63 is slidably guided. A compression spring 71 surrounding the guide sleeve 67 is clamped between the bottom 19 of the lid member 2 and the plate-shaped closure body 63 of the bypass valve and biases the bypass valve to a closed position. As can be seen most clearly in Figures 4 and 6, the upper end cap 13 has near its periphery a rim of a passage 73 which provides a fluid path from the upper surface 27 of the end cap 13 to the gap 57 located therebelow. When the bypass valve is opened by the pressure of the nonfiltrate, the nonfiltrate flowing into the interior chamber 17 of the lid member can pass through the passage 73 to the filtrate side in the gap 57 and from there through the outlet pipe 3 to the inside of the tank.

[0022] If the guide for the outflow pipe 3 is formed by a wing-shaped flat strip material 55, the outflow pipe 3 can be formed from a thin-walled sheet of material, for example in the form of a plastic film. A multi-layer construction can be provided in a particularly advantageous manner. For example, a two-layer construction can improve the outflow behavior and facilitate the degassing of the fluid. As shown in FIG. 4, the end 38 of the outflow pipe 3 is located at a small distance from the base 40 of the annular guide space 37. An axial play is thus provided for the inserted end of the outflow pipe 3, which can compensate for length errors in the spacing of the end caps 13, 14 and thus prevent possible bulging of the outflow pipe 3. The present invention has the following aspects (configurations). [Aspect 1] A filter device comprising a filter housing (1) having a cover member (2) and a replaceable filter element (7) therein, A filter device in which the element member (9) of the filter element (7) extends between two end caps (13) of the filter element (7), The filter device is characterized in that the filter housing (1) is configured as an outlet pipe (3) and extends between two end caps (13, 14). [Aspect 2] The filter device of aspect 1, characterized in that a slot-shaped annular guide space (37, 80) is provided in each of the two end caps (13, 14) to form a receiving portion for the assigned end (38) of the outflow pipe (3), and the annular guide space (37, 80) at least partially contacts the inner and outer wall portions of the outflow pipe (3). [Aspect 3] The filter device according to aspect 1 or 2, characterized in that an annular guide space in the end cap (13, 14), preferably the end cap (13) assigned to the cover member (2), allows axial play for the assigned end (38) of the outflow tube (3). [Aspect 4] The filter device according to any one of aspects 1 to 3, characterized in that the support pipe (11) extending outside the element member (9) between the two end caps (13, 14) has a support structure consisting of vertical beam members (55) and horizontal beam members (53), the vertical beam members (55) and the horizontal beam members (53) leave a fluid passage open, and at least the vertical beam members (55) are aligned parallel to the longitudinal axis of the filter element (7) to support the element member (9) on the inner peripheral side, and function as a spacer to form a gap (57) between the element member (9) and the outflow pipe (3). [Aspect 5] A filter device according to any one of aspects 1 to 4, characterized in that the support tube (11) consists of individual partial segments (49) arranged one behind the other and latchable to one another by latching means, the two outer partial segments (49) having towards their free outer ends latching means (47, 51) for latching the end caps (13, 14) which can respectively be assigned thereto. [Aspect 6] The filter device according to any one of aspects 1 to 5, wherein the end cap (13) assigned to the cover member (2) is latched to the inner surface of the cover member (2) by a latch bar (28). [Aspect 7] 7. The filter device according to any one of aspects 1 to 6, wherein the outflow pipe (3) is formed in a single layer or multiple layers and is provided with passages (5, 6). [Aspect 8] The filter device according to any one of aspects 1 to 7, wherein unfiltrated liquid is supplied to the inside (35) of the filter element (7) through a lower end cap (14) facing away from the cover member (2), and filtrate is discharged through the outside of the filter element (7) toward the outlet pipe (3). [Aspect 9] 9. The filter device according to any one of aspects 1 to 8, wherein a bypass valve (67) is integrated into the cover member (2), and when the bypass valve (67) is in an open state, the bypass valve (67) forms a fluid path in an inner chamber (17) of the cover member (2) through an opening (62) of an end cap (13) assigned to the cover member (2), and the end cap (13) has a passage (73) near its periphery that opens into a gap (57) inside the outflow pipe (3).

Claims

1. A filter device comprising a filter housing (1) having a cover member (2) and a replaceable filter element (7) therein, A filter device in which the element member (9) of the filter element (7) extends between two end caps (13) of the filter element (7), The filter housing (1) is configured as an outlet pipe (3) and extends between two end caps (13, 14), a slot-like annular guide space (37, 80) is provided in each of the two end caps (13, 14) to form a receiving portion for an assigned end (38) of the outlet pipe (3), the annular guide space (37, 80) being at least partially in contact with the inner and outer peripheral walls of the outlet pipe (3); A filter device comprising:

2. 2. The filter device according to claim 1, characterized in that annular guide spaces in the end caps (13, 14) allow axial play for the assigned end (38) of the outlet pipe (3).

3. 3. The filter device according to claim 1 or 2, characterized in that the support pipe (11) extending outside the element member (9) between the two end caps (13, 14) has a support structure consisting of vertical beam members (55) and horizontal beam members (53), the vertical beam members (55) and the horizontal beam members (53) leave a fluid passage open, and at least the vertical beam members (55) are aligned parallel to the longitudinal axis of the filter element (7) to support the element member (9) on the inner peripheral side, and function as a spacer to form a gap (57) between the element member (9) and the outflow pipe (3).

4. 4. The filter device according to claim 3, characterized in that the support tube (11) is made up of individual part segments (49) arranged one behind the other and latchable to one another by latching means, the two outer part segments (49) having towards their free outer ends latching means (47, 51) for latching the respective assignable end caps (13, 14).

5. The filter device according to any one of claims 1 to 4, characterized in that the end cap (13) assigned to the lid element (2) is latched on the inner surface of the lid element (2) by means of a latch bar (28).

6. 6. The filter device according to claim 1, wherein the outlet pipe (3) is made of a single layer or of multiple layers and is provided with passages (5, 6).

7. 7. The filter device according to claim 1, wherein unfiltered liquid is supplied to the inside (35) of the filter element (7) through a lower end cap (14) facing away from the cover member (2), and filtrate is discharged through the outside of the filter element (7) towards the outlet pipe (3).

8. 8. The filter device according to claim 1, characterized in that a bypass valve (67) is integrated in the cover element (2), which in the open state forms a fluid path to the inner chamber (17) of the cover element (2) through an opening (62) in an end cap (13) assigned to the cover element (2), the end cap (13) having, in the vicinity of its periphery, a passage (73) opening into the gap (57) inside the outlet pipe (3).

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