Filtration system with primary and secondary filtration elements and a secondary filtration element of such a filtration system - Patents.com

Abstract

The present invention relates to a filtration system (100) having a housing (110), an inlet (102) formed in a housing wall (112), an outlet (108) formed in a housing wall (120), and a primary filtration element (50) and a secondary filtration element (10) housed in the housing (110). The secondary filtration element (10) is positioned downstream from the primary filtration element (50) on a standpipe (150). The standpipe (150) is fixedly connected to one of the housing walls (120), and the interior of the standpipe (150) is fluidly connected to the outlet (108). The secondary filtration element (10) includes a filter medium (16) forming a body (36) having at least one longitudinal seam (18) along a longitudinal axis (L). The secondary filtration element (10) and the standpipe (150) are connected to one another at one of their respective top regions (12, 152) by connecting elements (22, 156). The secondary filtration element (10) and the standpipe (150) have mutual self-positioning elements (30, 180) configured to position the secondary filtration element (10) on the standpipe (150) in a defined rotational position relative to one or more struts (170) of the standpipe (150).

Description

[Technical field]

[0001] The present invention relates to a filtration system, in particular for air filter systems of internal combustion engines, comprising a primary and a secondary filtration element, as well as to a secondary filtration element of such a filtration system. [Background technology]

[0002] It is known to use air filters to control the combustion intake of internal combustion engines, such as passenger cars, commercial vehicles, work machines, agricultural vehicles, stationary generators, and the like. Such air filters generally have a housing, an inlet, and an outlet, with a removable and replaceable main or primary filtering element disposed within the housing. The housing is often provided with a maintenance cover to provide access to the filtering element within the housing during maintenance. This allows the filtering element to be removed and replaced with a new filtering element, or to be overtaken and reused, or to be replaced with a previously used and overtaken filtering element.

[0003] The filtering elements of air filters are usually replaced after a certain operating time. Depending on the load of dust that accumulates on the filtering elements during use, the service life of the filter can range from a few days when used in construction machinery, for example, to a maximum of a few months in a dusty environment.

[0004] It is important to ensure a process-proof seal of the filter element in the housing, especially if the filter element is replaced frequently. The seal should be heat-resistant and vibration-tested. It is also necessary to ensure the sealing of the filter element in systems and devices that are exposed to strong vibrations. At the same time, however, the filter element itself should preferably not contain metal elements, in order to provide problem-free thermal disposal. In order to protect the clean side of the air cleaner system of the internal combustion engine from the ingress of dirt particles when replacing the primary filter element, so-called "secondary filter elements" are used, which remain in the filter housing even when the primary filter element is replaced. The secondary filter element is usually arranged on the clean side of the filter element, for example inside the primary filter element, and is connected to the housing of the filter system. The secondary filter element itself also has a filter medium, which directs residual dirt particles in the air flow away from the filter outlet.

[0005] The secondary filtration element itself can be replaced at will, depending on the load of dirt particles, and has a much longer lifespan than the primary filtration element.

[0006] US Patent No. 8,480,778 discloses an air filter system, in which a secondary filter element is made of a filter medium configured as a hollow cylinder, one end of which is closed by a closed end cap and the other end of which is open. The open end allows the filter element to slide on a support tube connected to a filter housing, which protects the outlet of the filter system from dirt particles. The primary filter element is placed on the free end of the support tube and thus on the end cap of the secondary filter element. The primary filter element is attached to the secondary filter element. Other air filter systems are known from US Patent Application Publication No. 2018 / 036667 and WO 2018 / 111434. Summary of the Invention

[0007] It is an object of the present invention to provide a filtration system containing a secondary filtration element that ensures defined fluid flow characteristics so that a mass flow sensor within the filtration system has a reliable operating condition.

[0008] It is a further object of the present invention to provide a secondary filtration element for such a filtration system.

[0009] The above-mentioned objects are achieved according to one aspect of the present invention by a filtration system having a housing, an inlet and an outlet, respectively, formed in the housing wall, and a primary filtration element and a secondary filtration element, the secondary filtration element being disposed on a standpipe downstream from the primary filtration element, the standpipe being fixedly connected to one of the housing walls, an interior of the standpipe being fluidly connected with the outlet, the secondary filtration element including a filter medium forming a body having at least one longitudinal seam along a longitudinal axis, the secondary filtration element including an end cap at a top region, the secondary filtration element and the standpipe being connected to each other at one of their respective top regions by a connecting element, the secondary filtration element and the standpipe having mutual self-positioning elements configured to position the secondary filtration element on the standpipe in a defined rotational position relative to one or more struts of the standpipe, and by a secondary filtration element of such a filtration system according to another aspect of the present invention.

[0010] Advantageous embodiments and advantages of the invention are described in the further claims, the description and the drawings.

[0011] According to a first aspect of the present invention, a filtration system is proposed having a housing, an inlet formed in the housing wall, an outlet formed in the housing wall, and a primary filtration element and a secondary filtration element housed in the housing. The secondary filtration element is disposed on the standpipe downstream from the primary filtration element. The standpipe is fixedly connected to one of the housing walls, and an interior of the standpipe is fluidly connected to the outlet. The secondary filtration element includes a filter medium forming a body having at least one longitudinal seam. The secondary filtration element includes an end cap at a top region. The secondary filtration element and the standpipe are connected to each other at one of their respective top regions by a connecting element. The secondary filtration element and the standpipe have mutual self-positioning elements configured to position the secondary filtration element on the standpipe in a defined rotational position relative to one or more struts of the standpipe.

[0012] According to a preferred embodiment, a first axial end of the standpipe is connected to the housing wall and an opposite second axial end of the standpipe defines a top region of the standpipe. Preferably, the connecting element of the standpipe is located in the top region of the standpipe. More preferably, the one or more connecting elements of the secondary filtration element are provided on end caps of the secondary filtration element, and the secondary filtration element and the standpipe are connected to each other by connecting the connecting elements provided on the end caps and the standpipe.

[0013] Advantageously, the standpipe is fixedly connected to the bottom wall of the housing, so that the position of the longitudinal struts is known. By locating the secondary filtration element in a well-defined rotational position relative to one or more struts of the standpipe, the disturbance of the flow characteristics due to one or more longitudinal seams of the filter medium can be reduced or eliminated. The seams can be located radially in front of one particular strut or between two longitudinal struts. As a result, the position of one or more seams of the secondary filtration element on the standpipe is also known. This allows the longitudinal struts of the standpipe and the seams of the secondary filtration element to be located relative to the mass flow sensor in a preferred air filter system for an internal combustion engine such that the flow characteristics of the fluid, i.e., the air, are known in the area of ​​the mass flow sensor and the measurements of the mass flow sensor are accurate. Also, the mutual self-locating elements of the secondary filtration element and the standpipe allow the longitudinal seams of the filter medium of the secondary filtration element to be located in a specific position. As a result, the disturbance of the flow effects of the longitudinal seams on the flow characteristics can be reduced or eliminated. Additionally, when the secondary filtration element is replaced, repeatable positioning of the one or more seams relative to the mass flow sensor is possible.

[0014] Further advantages of such a filtration system are the safe and stable assembly of both the primary and secondary filtration elements, as well as the very economical replaceability of the primary filtration element during maintenance, and, if necessary, the secondary filtration element.

[0015] The filter medium of the secondary filtration element can be made of nonwoven fabric, or of paper or cellulose, or of mixed fibers of plastic and cellulose. The material can be selected according to the intended use. Advantageously, the filter medium is designed to be continuous in the circumferential direction of the secondary filtration element with at least one longitudinal seam. For example, a flat surface of the filter medium can be used to manufacture the secondary filtration element by wrapping it around a correspondingly shaped member and welding the open ends closed along the longitudinal seam. This allows the secondary filtration element to be airtight.

[0016] According to a preferred embodiment, the mutual self-positioning elements include a guide surface and a protruding element, the guide surface configured to guide the protruding element from an initial position to a final position in which the secondary filtration element is in a defined rotational position relative to one or more struts of the standpipe. A suitable pair of mutual self-positioning elements may be selected.

[0017] According to a preferred embodiment, the mutual self-positioning element includes a contour disposed on an outer surface of one of the standpipe and the secondary filtration element, and a mating contour disposed on an inner surface of the other of the standpipe and the secondary filtration element. Preferably, the polygonal contour of the standpipe can be used to position and attach the standpipe to the bottom wall of the housing. Also, by providing a suitable mating contour on the secondary filtration element, such contour can be used to align the secondary filtration element on the standpipe.

[0018] According to a preferred embodiment, the top region of the standpipe includes a receiving portion for receiving an end cap of the secondary filtration element, the receiving portion having a bottom segment and a top segment aligned with the longitudinal axis, the receiving portion may be shaped to conform to the end cap of the secondary filtration element to securely connect the two components.

[0019] According to a preferred embodiment, the end cap of the secondary filtration element has a recess intended to extend into the interior of the standpipe, in particular the recess extends towards the bottom segment in the accommodation. This allows a safe and secure assembly of the secondary filtration element and the standpipe. In particular, the bottom segment provides at least one mutual self-positioning element, while the top segment may not have at least one mutual self-positioning element. Advantageously, the end cap is at least partially inserted into the top segment without contacting the self-positioning element in the accommodation and is safely guided to the final position.

[0020] According to a preferred embodiment, the top segment of the receiving part has a depth in the receiving part, which is equal to or greater than the longitudinal clearance of the outermost longitudinal surface of the projection element. Preferably, the end cap is introduced into the receiving part and moved to a final position in the receiving part without tilting. In particular, the connecting element of the end cap is inserted into the receiving part without getting stuck.

[0021] According to a preferred embodiment, the connection elements for connecting the secondary filtration element and the standpipe comprise snap-fit ​​elements, in particular one or more snap beams and engagement elements for said snap beams, which allows a reliable connection to be established. The dimensions of the components can be easily adapted to the needs of the actual filtration system.

[0022] According to a preferred embodiment, the length of the snap beam is adjusted to the longitudinal extent of the receiving part such that the connecting elements of the secondary filtration element and the standpipe connect when or after the projection element reaches its final position, thereby ensuring the rotational and axial position of the secondary filtration element on the standpipe in a single joint installation step.

[0023] According to a preferred embodiment, the guide surface comprises at least one, preferably helical, inclined surface. Preferably, the guide surface comprises two helical inclinations, which extend in counter-rotational directions from an apex position to a minimum axial position.

[0024] According to a preferred embodiment, pockets are arranged in the guide surface which receive the protruding elements when the secondary filtering element is at or near its final position, thereby ensuring a secure fixation of the protruding elements.

[0025] According to a preferred embodiment, a notch is arranged in the guide surface that receives the protruding element when the secondary filtration element is in the final position, which allows a secure fixation of the protruding element and also facilitates removal of the secondary filtration element from the standpipe.

[0026] According to a further aspect of the invention, a secondary filtration element of the filtration system of the invention is proposed, which comprises a filter medium forming a body having at least one longitudinal seam, in particular a welded seam, along a longitudinal axis, and an end cap located in a top region. The end cap comprises one or more connection elements configured to connect the secondary filtration element to a standpipe of the filtration system. The end cap has a self-positioning element configured to position the secondary filtration element on the standpipe of the filtration system in a defined rotational position relative to one or more struts of the standpipe of the filtration system.

[0027] Preferably, the secondary filtration element is conical, the diameter of which decreases from the open end to the closed end. This allows easy assembly of the secondary filtration element to the standpipe. Advantageously, the connection element forms part of a snap-fit ​​connection. The connection element may thus comprise a snap beam and a counter-part on the standpipe side on which the snap beam hooks can be hooked. Similarly, the reverse configuration is also possible.

[0028] According to a preferred embodiment, the end cap of the secondary filtration element has a pot shape and the self-positioning element extends into the interior of the filtration medium, allowing for secure connection and positioning to the standpipe of the filtration system.

[0029] According to a preferred embodiment, the end cap is fixedly connected to the filter media, in particular by welding, gluing, spraying, foam molding, etc. The type of connection can be selected to suit the intended application.

[0030] According to a preferred embodiment, the end cap includes an axially extending protruding element, which can be used as a self-positioning element when mounting the secondary filtration element on a standpipe of the filtration system. In particular, the protruding element is arranged eccentrically on the end cap with respect to a central axis of the end cap, which can be the longitudinal axis of the secondary filtration element. The protruding element can be used as a means for guiding the movement of the end cap, and thus the secondary filtration element, during assembly on the standpipe, which is preferably provided with a radially extending guide surface in the receiving part.

[0031] Advantageously, the filtration system and the secondary filtration element of the invention can be used as an air filter, in particular as an air filter for an internal combustion engine. The safe operation of an internal combustion engine is based on a safe and favorable filtration of the intake air for combustion, in particular with undisturbed flow characteristics of the air at the mass flow sensor. The above-mentioned filtration system shows economical and reliable possibilities for this purpose. Advantageously, the filtration system can also be used as a particle filter, in particular as a particle filter for an internal combustion engine. In this case too, the safe assembly and economical interchangeability of the above-mentioned filtration elements are advantageous. Advantageously, when changing the primary filtration element, the secondary filtration element can remain in the housing. This allows the clean side of the filtration system to be effectively protected from the ingress of dirt particles during maintenance of the filtration system.

[0032] It is to be understood that the present invention may be combined with one or more of the features disclosed in the patent applications entitled "Filtration System Comprising Primary and Secondary Filtration Elements and a Secondary Filtration Element of Such a Filtration System" and "Filtration System Comprising Primary and Secondary Filtration Elements and a Primary Filtration Element of Such a Filtration System", which were filed by the applicant together with this patent application on the same date.

[0033] Further advantages are obtained from the following description of the drawings, in which embodiments of the invention are illustrated. The drawings, the description and the claims contain a number of features in combination, which the skilled person can consider individually and combine to provide further combinations. [Brief description of the drawings]

[0034] [Figure 1] 1 is a longitudinal cross-sectional view of a filtration system according to an embodiment of the present invention. [Diagram 2] FIG. 2 is an exploded view of the filtration system of FIG. 1. [Diagram 3] 1 illustrates a first embodiment of a secondary filtration element with end caps having recesses on their outer surfaces. [Figure 4] 1 shows a second embodiment of a secondary filtration element with end caps having knobs on their outer surfaces. [Diagram 5] 1 shows the bottom wall of the housing of the filtration system with a standpipe attached to the bottom wall of the housing. [Figure 6] 4 is a longitudinal cross-sectional view of the top region of the secondary filtration element of FIG. 3. [Figure 7] 4 is another longitudinal cross-sectional view of the top region of the secondary filtration element of FIG. 3. [Figure 8] FIG. 4 is a top view of the secondary filtration element of FIG. 3. [Figure 9] FIG. 4 is an isometric view of the inside of the end cap of the secondary filtration element of FIG. [Figure 10] FIG. 4 is an isometric view of the outside of the end cap of the secondary filtration element of FIG. [Figure 11] FIG. 6 is a longitudinal cross-sectional view of the standpipe of FIG. 5, showing the guide surfaces within the receptacle in the top region. [Figure 12] FIG. 12 is a longitudinal cross-sectional view of the standpipe of FIG. 11 rotated 90° about its longitudinal axis, showing pockets in the guide surface. [Figure 13] FIG. 12 is a longitudinal cross-sectional view rotated 180° about the longitudinal axis of the standpipe of FIG. 11 showing pockets in the guide surface. [Figure 14] FIG. 12 is an isometric top view of the top region of the standpipe of FIG. [Figure 15] FIG. 6 is a detailed view showing the initial contact of the secondary filtration element of FIG. 3 and the standpipe of FIG. 5 during assembly. [Figure 16] 6 is a detailed view of the secondary filtration element of FIG. 3 and the standpipe of FIG. 5 after assembly, with the secondary filtration element in its final position, with the protruding elements of the end cap secured in the pockets of the receiving portion of the standpipe. [Figure 17] 5 is a longitudinal cross-sectional view of the top region of the secondary filtration element of FIG. 4. [Figure 18] 5 is another longitudinal cross-sectional view of the top region of the secondary filtration element of FIG. 4. [Figure 19] FIG. 5 is a top view of the secondary filtration element of FIG. 4. [Figure 20] FIG. 5 is an isometric view of the inside of the end cap of the secondary filtration element of FIG. [Figure 21] FIG. 5 is an isometric view of the outside of the end cap of the secondary filtration element of FIG. [Figure 22] FIG. 6 is a longitudinal section of the standpipe similar to FIG. 5, showing the guide surfaces in the receptacle in the top region. [Figure 23] FIG. 23 is a longitudinal cross-sectional view of the standpipe of FIG. 22 rotated 90° about its longitudinal axis, showing the notches in the guide surface. [Figure 24] FIG. 23 is a longitudinal cross-sectional view rotated 180° about the longitudinal axis of the standpipe of FIG. 22, showing the notches in the guide surface. [Diagram 25] FIG. 23 is an isometric top view of the top region of the standpipe of FIG. [Figure 26] FIG. 23 is a detailed view showing the initial contact of the secondary filtration element of FIG. 4 and the standpipe of FIG. 22 during assembly. [Figure 27] 23 is a detailed view of the secondary filtration element of FIG. 4 and the standpipe of FIG. 22 after assembly with the secondary filtration element in its final position with the protruding elements of the end cap secured in the notches of the receiving portion of the standpipe. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] These figures are illustrative only and not limiting, in which similar or identical elements are designated with the same reference numbers.

[0036] Fig. 1 is a longitudinal cross-sectional view of a filtration system 100 according to an embodiment of the present invention. Fig. 2 is an exploded view of the filtration system 100 of Fig. 1.

[0037] The filtration system 100 has a housing 110, an inlet 102 formed in a housing wall 112, and an outlet 108 formed in a bottom housing wall 120. In this embodiment, the housing 110 may be composed of three parts, namely, a bottom housing wall 120, an annular middle housing wall 112 having the inlet 102, and a lid 114. These parts are connected to each other, for example, by clamps. The housing 110 accommodates a hollow cylindrical primary filtration element 50. To remove the primary filtration element 50 for maintenance or replacement, the housing walls 112, 114 may be detached together from the bottom housing wall 120, or only the lid 114 may be removed.

[0038] The main body of the primary filtration element 50 is, for example, composed of pleated filter media 56. The primary filtration element 50 is covered at both ends by annular end plates 52, 54, for example made of polyurethane as known in the art. Sealing structures and support ribs are arranged on the outside of the end plates 52, 54. The primary filtration element 50 is hermetically fixed between the bottom wall 120 and the lid 114 such that the fluid must pass radially through the primary filtration element 50, as shown by the thick arrow in FIG. 1. The end plates 54 of the primary filtration element 50 are received in the bottom housing wall 120, which has a groove 126. An annular projection 128 is arranged in the groove 126 to radially fix the primary filtration element 50.

[0039] The lid 114 has a recess 138 on its front surface 130 that extends into the interior of the housing 110 .

[0040] Disposed within the primary filtration element 50 is the secondary filtration element 10. The primary and secondary filtration elements 50, 10 are concentrically disposed about a longitudinal axis L. The secondary filtration element 10 is disposed downstream of the primary filtration element 50 such that fluid must pass through the secondary filtration element 10 on its way to an outlet 108. The secondary filtration element 10 is disposed on a standpipe 150 that is fixedly connected to the bottom housing wall 120. A lower portion of the standpipe 150 merges with the outlet 108 in the bottom housing wall 120. The secondary filtration element includes a filter medium 16 forming a body 36 having at least one welded seam 18 along the longitudinal direction L.

[0041] The secondary filtration element 10 includes a closed end cap 20 at the top region 12, and the secondary filtration element 10 and the standpipe 150 are interconnected at their top regions 12, 152 by a connecting element. The open end side of the secondary filtration element 10 is received in a circular groove 122 in the bottom wall 120.

[0042] FIG. 3 shows a first embodiment of a secondary filtration element 10 with an end cap 20 having a recess 24 on its outer surface. The secondary filtration element 10 has a body 36 made of a filter medium 16. The filter medium 16 can be a nonwoven material, paper, cellulose, or a mixed fiber of plastic and cellulose. The filter medium 16 is designed to be continuous in the circumferential direction of the secondary filtration element 10 with at least one longitudinal seam 18. The formed filter body 36 has a conical shape with a larger diameter at the bottom surface 14 and a smaller diameter at the top region 12 of the body 36, where the end cap 20 is attached. Preferably, the filter medium 16 is connected to the end cap 20 via a circumferential welded seam 28. The recess 24 of the end cap 20 extends into the interior of the body 36.

[0043] FIG. 4 shows a second embodiment of the secondary filtration element 10 with an end cap 20 having a knob 40 on its outer surface. The secondary filtration element 10 has a body 36 made of a filter medium 16. The filter medium 16 can be a nonwoven material, paper, cellulose, or a mixed fiber of plastic and cellulose. The filter medium 16 is designed to be continuous in the circumferential direction of the secondary filtration element 10 with at least one welded seam 18 in the longitudinal direction. The filter body 36 formed therein has a conical shape with a larger diameter at the bottom surface 14 and a smaller diameter at the top region 12 of the body 36 to which the end cap 20 is attached. Preferably, the filter medium 16 is connected to the end cap 20 via a circumferential welded seam 28. The recess 24 of the end cap 20 extends into the interior of the body 36. The recess 24 accommodates a bridge-like knob 40 that spans the recess 24. Knob 40 can be used to attach and remove secondary filtration element 10 to and from standpipe 150. Secondary filtration element 10 can be attached by rotating secondary filtration element 10 about its longitudinal axis, and secondary filtration element 10 can be removed from standpipe 150 by rotating knob 40 in the opposite rotational direction.

[0044] 5 shows the bottom wall 120 of the filtration system 100 with the standpipe 150 attached to the bottom wall 120 of the housing 110. The lattice body of the standpipe 150 is conical and is composed of longitudinal struts 170 and circumferential struts 172. For clarity, only two of each are labeled with reference numerals.

[0045] The standpipe 150 is provided as a carrier for the secondary filtration element 10, as shown in Figures 3 and 4. The secondary filtration element 10 and the standpipe 150 each have complementary connection means that allow them to be connected to each other at one of their end faces, as shown in the upper part of Figures 3 to 5. This allows a safe and stable assembly of the primary filtration element 50 (Figures 1, 2) and the secondary filtration element 10, as well as a very economical replacement of the primary filtration element 50 during maintenance and, if necessary, the secondary filtration element 10. The secondary filtration element 10 is fixedly arranged on the standpipe 150. The closed end cap 20 of the secondary filtration element 10 allows the clean side of the filtration system 100 to be protected from particulate matter, even when the primary filtration element 50 is removed and even when fluid is drawn through the secondary filtration element 10.

[0046] 6-10 show in greater detail a first embodiment of the secondary filtration element 10 with closed end cap 20 of FIG.

[0047] Figures 6-8 show top region 12 of secondary filtration element 10 with end cap 20 from different perspectives. Figure 6 is a longitudinal cross-section, Figure 7 is a longitudinal cross-section of top region 12 rotated 90° about its longitudinal direction, and Figure 8 is a top view of secondary filtration element 10. Figure 9 is an isometric view of the inside of end cap 20 of secondary filtration element 10, and Figure 10 is an isometric view of the outside of end cap 20.

[0048] End cap 20 of secondary filtration element 10 includes a recess 24 having a closed lower region 26 that extends into a body 36 of secondary filtration element 10. Body 36 is comprised of a filter media attached, e.g., by welding, adhesive, etc., to a flange of end cap 20 at a circumferential seam 28.

[0049] The end cap 20 has a pot shape with two parts, a flanged upper segment 21 with a larger diameter and a lower segment 26 with a smaller diameter. At the interface between the upper segment 21 and the lower segment 26, a step 25 is formed due to the different diameters of the segments 21, 26. The lower segment 26 has a conical section at the interface and a tapered section towards a closed bottom 27. On the outside of the bottom 27, a connecting element 22, for example configured as a snap beam 23, further extends in the longitudinal direction. The connecting element 22 is configured to cooperate with one or more corresponding connecting elements of the standpipe 150.

[0050] Located within recess 24 is self-positioning element 30, configured, for example, as protruding element 32. Protruding element 32 extends from step 25 at the interface between upper segment 21 and lower segment 26 toward the beginning of the tapered portion of lower segment 26. When viewed from the top of end cap 20, protruding element 32 forms a recess at step 25 between upper segment 21 and lower segment 26 and may open toward lower segment 26.

[0051] The end cap 20 is configured to extend into the interior of the standpipe 150 (FIG. 5). In particular, the recess 24 of the end cap 20 extends into the interior of the receiving portion 160 of the standpipe 150. At the mounting position of the secondary filtration element 10 on the standpipe 150, the connecting element 22 cooperates with the mating element 156 and the self-positioning element 30 (the protruding element 32) cooperates with the mating self-positioning element 180 of the standpipe 150 for axial connection.

[0052] Figures 11-14 show a first embodiment of a standpipe 150 for use with a secondary filtration element 10 with an end cap 20 as described in Figures 6-10. Figure 11 is a longitudinal cross-section of the standpipe 150, Figure 12 is a longitudinal cross-section rotated 90° about the longitudinal axis, Figure 13 is a longitudinal cross-section rotated 180° about the longitudinal axis, and Figure 14 is an isometric top view of the top region 164 of the standpipe 150.

[0053] The standpipe 150 provides a guide surface 182 as a self-positioning element 180 in the receiving section 160 in the top region 152 of the standpipe 150. The guide surface 182 is provided on the outer shell of the receiving section 160 and is inclined on both sides from the top axial position to the minimum axial position. The guide surface 182 can therefore be described as including at least one, preferably helical, inclined surface. Preferably, the guide surface includes two inclined portions, which extend in counter-rotating directions from the top position to the minimum axial position. The guide surface 182 extends radially inwards, so that the protruding element 32 can move on the guide surface 182. Preferably, at the minimum axial position, a pocket 186 is arranged, which is configured to accommodate the protruding element 32 (Figures 6 to 10) of the secondary filtration element 10. Preferably, the pocket 186 is arranged directly opposite a maximum point 190 of the guide surface 182. This means that preferably the two inclined portions end at the pocket position from opposite ends, respectively.

[0054] The contour of the receiving section 160 corresponds to the outer contour of the end cap 20 of the secondary filtration element 10. The receiving section 160 has an open bottom with a connecting element 156 at its end for the connecting element 22 of the secondary filtration element 10. That is, as an engagement element 157, the snap beam 23 can be hooked to the bottom of the receiving section 160, and a snap fit between the standpipe 150 and the secondary filtration element 10 is formed. The receiving section 160 is funnel-shaped in its bottom region to facilitate the introduction of the snap beam 23.

[0055] A ring having a polygonal radial outer surface is arranged on the surface of the top region 152 of the standpipe 150. The polygonal contour 184 allows the standpipe 150 to be attached to the bottom wall 120 of the housing 110 (FIGS. 1, 2) in a specific position. In particular, the longitudinal struts 170 can be arranged in a well-defined rotational position relative to the bottom wall of the housing. This allows the longitudinal struts 170 of the standpipe 150 to be arranged relative to the mass flow sensor in an air filter system for an internal combustion engine such that the flow characteristics of the fluid, i.e. the air, are known in the area of ​​the mass flow sensor and the measurements of the mass flow sensor are accurate. The mutual self-positioning elements 30, 180 of the secondary filtration element and the standpipe 150 also allow the longitudinal seam of the filter medium of the secondary filtration element to be located in a specific position. As a result, the influence of the weld seam on the flow characteristics as a disturbance of the flow can be reduced or eliminated.

[0056] In an embodiment not shown, contour 184 may be used as a self-positioning element for specific positioning of secondary filtration element 10 on standpipe 150 (not shown). The hexagonal contour allows for placement of secondary filtration element 10 in six specific rotational positions on standpipe 150. In this case, end cap 20 of secondary filtration element 10 has a shape following the corresponding contour.

[0057] Figures 15 and 16 show how the secondary filtration element 10 according to the first embodiment of Figure 3 is attached to the standpipe 150 in a self-locating manner. Figure 15 is a detailed view of the secondary filtration element 10 of Figure 3 and the standpipe 150 of Figure 5 in initial contact during assembly. Figure 16 is a detailed view of the assembled secondary filtration element 10 and standpipe 150 with the secondary filtration element 10 in its final position with the protruding elements 32 of the end caps 20 secured in the pockets 186 of the receiving portions 160 of the standpipe 150.

[0058] To attach the secondary filtration element 10 to the standpipe 150 , the body 36 of the secondary filtration element 10 is placed onto the standpipe 150 and moved along the standpipe 150 until the end cap 20 is adjacent to the receiving portion 160 of the standpipe 150 .

[0059] The end cap 20 is first inserted into the receiving part 160 by the snap beam 23 towards the funnel-shaped bottom region of the receiving part 160. The end cap 20 can be introduced into the receiving part 160 until the projection element 32 abuts against the guide surface 182. The longitudinal extent 90 of the projection element 32 is smaller than the depth 168 of the top segment 162 of the receiving part 160. The top segment 21 of the end cap can thus be partially inserted into the top segment 162 such that the step 25 is located securely in the receiving part 160. As a result, the end cap 20 can be guided further into the receiving part 160 safely without tilting.

[0060] The guide surface 182 has a maximum point 190 at the bottom segment 164 of the housing 160 and is sloped on either side of the maximum point 190. The maximum point 190 of the guide surface 182 is at the interface of the top segment 162 and the bottom segment 164 of the housing 160. Rotating the end cap 20 in either direction about the longitudinal axis L will cause the protruding element 32 to move further within the housing 160 as the protruding element 32 is guided on the guide surface 182 until the protruding element 32 reaches the pocket 186 in the guide surface 182.

[0061] Now, the end cap 20 is moved axially until the protruding element 32 is received in the pocket 186. The snap beam 23 also moves axially downwards so that it can snap against the edge of the funnel-shaped bottom segment 164, which is the engagement element 157 of the standpipe 150. The snap beam 23 securely fastens the end cap 20 to the standpipe 150. The end cap 20 can be removed from the standpipe 150 in the opposite movement sequence by pulling and turning the end cap 20.

[0062] A tool, such as a handle, may be attached to the recess 24 of the end cap 20 to rotate the end cap 20 .

[0063] With the protruding elements 32 received in the pockets 186, the secondary filtration element 10 is precisely positioned in a well-defined rotational position relative to the standpipe 150. Thus, the longitudinal weld seams (not shown) are well-defined relative to the longitudinal struts 170 of the standpipe 150, and thus relative to the mass flow sensor located in a specific position close to the filtration element. Preferably, the hooks of the snap beams 23 have an inclined surface to allow them to loosen when some force is applied to the end cap 20.

[0064] The length of the end cap 20 with the snap beam 23 matches the depth of the receptacle 160 so that the snap beam 23 contacts the funnel-shaped end of the receptacle 160, i.e., the engagement element 157, when the end of the protruding element 32 reaches into the pocket 186. The step 25 of the end cap 20 rests on the maximum point 190 of the guide surface 182 in the receptacle 160.

[0065] 17-21 show in greater detail a second embodiment of the secondary filtration element 10 with closed end cap 20 of FIG.

[0066] Figures 17-19 show different views of the top region 12 of the secondary filtration element with the end cap 20. Figure 17 is a longitudinal cross-section, Figure 18 is a longitudinal cross-section of the top region 12 rotated 90° about its longitudinal direction, and Figure 19 is a top view of the secondary filtration element 10. Figure 20 is an isometric view of the inside of the end cap 20 of the secondary filtration element 10, and Figure 21 is an isometric view of the outside of the end cap 20.

[0067] Its features are substantially the same as those of the secondary filtering element 10 of the first embodiment, in which respect reference is made to the description of the first embodiment.

[0068] Unlike the first embodiment, the end cap 20 has a bridge-like knob 40 within the recess 24. The knob 40 facilitates rotation and manipulation of the secondary filtration element 10 during installation and removal from the standpipe 150. No additional tools are required to manipulate the secondary filtration element 10.

[0069] To better stabilize knob 40 within recess 24 , the tapered region of lower segment 26 of recess 24 has a greater longitudinal extent than the tapered region in the first embodiment of secondary filtration element 10 .

[0070] 22-25 show a second embodiment of a standpipe 150 similar to that of FIG. 5 in conjunction with a secondary filtration element 10 having an end cap 20 as described in FIGS. 17-19.

[0071] FIG 22 is a longitudinal cross-sectional view of the standpipe 150 showing the guide surface 182 within the receptacle 160 of the top region 152 of the standpipe 150. FIG 23 is a longitudinal cross-sectional view rotated 90° about the longitudinal axis L of the standpipe 150, FIG 24 is a longitudinal cross-sectional view rotated 180° about the longitudinal axis L, and FIG 25 is an isometric top view of the top region 152 of the standpipe 150.

[0072] Its features are substantially the same as those of the standpipe 150 of the first embodiment, in which regard reference is made to the description of the first embodiment.

[0073] Unlike the first embodiment, the receiving portion 160 of the standpipe 150 comprises a guide surface having a notch 188 instead of a pocket 186. In this case, the notch 188 is a broad structure of the guide surface 182 created at the boundary of two branches that slope downwards from a maximum point 190 of the guide surface 182. Preferably, the notch 188 is located directly opposite the maximum point 190 of the guide surface 182.

[0074] 26 and 27 show how the secondary filtration element 10 is positioned on the standpipe 150. As shown in FIGS. 26 and 27, the bridge-like knob 40 facilitates removal of the secondary filtration element 10 from the standpipe 150. By rotating the end cap 20, and thus the secondary filtration element, about the axis L, the protruding element 32 slides along the guide surface 182 and descends into the housing 160. When the snap beam 23 reaches the notch 188, it hooks onto the edge of the funnel-shaped bottom segment 164 of the housing 160, which is the engagement element 157 of the snap beam 23. The step 25 of the end cap 20 rests on the maximum point 190 of the guide surface 182 in the housing 160.

Claims

1. A filtration system (100) having a housing (110), an inlet (102) formed in a housing wall (112), an outlet (108) formed in a housing wall (120), and a primary filtration element (50) and a secondary filtration element (10) housed in the housing (110), the secondary filtration element (10) is disposed on a standpipe (150) downstream from the primary filtration element (50), a first axial end of the standpipe (150) is fixedly connected to one of the housing walls (120), an interior of the standpipe (150) is fluidly connected to the outlet (108), and a top region (152) of the standpipe (150) is disposed axially opposite the first axial end and includes one or more connection elements (156) configured to connect to a connection element (22) of the secondary filtration element (10); The secondary filtration element (10) includes a filter medium (16) forming a body (36) having at least one longitudinal seam (18) along a longitudinal axis (L); the secondary filtration element (10) includes an end cap (20) at a top region (12), the end cap (20) including one or more connection elements (22) configured to connect to a connection element (156) of the standpipe; the secondary filtration element (10) and the standpipe (150) are connected to each other by the connecting element (22, 156); the end cap (20) of the secondary filtration element (10) and the standpipe (150) having mutual self-positioning elements (30, 180) configured to position the secondary filtration element (10) on the standpipe (150) in a defined rotational position relative to one or more struts (170) of the standpipe (150); The filtration system, wherein the mutual self-positioning elements (30, 180) include a guide surface (182) and a protrusion element (32), the guide surface (182) configured to guide the protrusion element (32) from an initial position to a final position in which the secondary filtration element (10) is in a defined rotational position relative to one or more struts (170) of the standpipe (150).

2. A filtration system (100) having a housing (110), an inlet (102) formed in a housing wall (112), an outlet (108) formed in a housing wall (120), and a primary filtration element (50) and a secondary filtration element (10) housed in the housing (110), the secondary filtration element (10) is disposed on a standpipe (150) downstream from the primary filtration element (50), a first axial end of the standpipe (150) is fixedly connected to one of the housing walls (120), an interior of the standpipe (150) is fluidly connected to the outlet (108), and a top region (152) of the standpipe (150) is disposed axially opposite the first axial end and includes one or more connection elements (156) configured to connect to a connection element (22) of the secondary filtration element (10); The secondary filtration element (10) includes a filter medium (16) forming a body (36) having at least one longitudinal seam (18) along a longitudinal axis (L); the secondary filtration element (10) includes an end cap (20) at a top region (12), the end cap (20) including one or more connection elements (22) configured to connect to a connection element (156) of the standpipe; the secondary filtration element (10) and the standpipe (150) are connected to each other by the connecting element (22, 156); the end cap (20) of the secondary filtration element (10) and the standpipe (150) having mutual self-positioning elements (30, 180) configured to position the secondary filtration element (10) on the standpipe (150) in a defined rotational position relative to one or more struts (170) of the standpipe (150); The mutual self-positioning elements (30, 180) include a contour (184) disposed on an outer surface of one of the standpipe (150) and the secondary filtration element (10), and a mating contour disposed on an inner surface of the other of the standpipe (150) and the secondary filtration element (10).

3. 3. The filtration system of claim 1, wherein the top region (152) of the standpipe (150) includes a receiving portion (160) for receiving an end cap (20) of the secondary filtration element (10), the receiving portion (160) having a bottom segment (164) and a top segment (162) along the longitudinal axis (L).

4. 4. The filtration system of claim 3, wherein the end cap (20) of the secondary filtration element (10) has a recess (24) intended to extend into the interior of the standpipe (150).

5. A filtration system as described in claim 4, wherein the recess (24) extends within the accommodating portion (160) toward the bottom segment (164).

6. 6. The filtration system of claim 3, wherein the bottom segment (164) provides at least one mutual self-positioning element (180) and the top segment (162) does not have the at least one mutual self-positioning element (180).

7. The mutual self-positioning element (30, 180) includes a guide surface (182) and a protruding element (32), the guide surface (182) configured to guide the protruding element (32) from an initial position to a final position in which the secondary filtration element (10) is in a defined rotational position relative to one or more struts (170) of the standpipe (150); 7. The filtration system of claim 3, wherein the top segment (162) of the housing (160) has a depth (168) within the housing (160), the depth (168) being equal to or greater than a longitudinal clearance (90) of an outermost longitudinal surface of the projection element (32).

8. The connection element (22) of the secondary filtration element (10) includes a first snap-fit ​​element, The filtration system of any one of claims 1 to 7, wherein the connection element (156) of the standpipe (150) comprises a second snap-fit ​​element.

9. The first snap-fit ​​element includes one or more snap beams (23), The filtration system of claim 8, wherein the second snap-fit ​​element includes an engagement element (157) for the snap beam (23).

10. The mutual self-positioning elements (30, 180) include a guide surface (182) and a protruding element (32), the guide surface (182) configured to guide the protruding element (32) from an initial position to a final position in which the secondary filtration element (10) is in a defined rotational position relative to one or more struts (170) of the standpipe (150); a top region (152) of the standpipe (150) including a receiving portion (160) for receiving an end cap (20) of the secondary filtration element (10); 10. The filtration system of claim 9, wherein the length of the snap beam (23) is adjusted to the longitudinal extent of the receiving portion (160) such that the connecting elements (22, 156) of the secondary filtration element (10) and the standpipe (150) connect when or after the protruding element (32) reaches its final position.

11. The mutual self-positioning elements (30, 180) include a guide surface (182) and a protruding element (32), the guide surface (182) configured to guide the protruding element (32) from an initial position to a final position in which the secondary filtration element (10) is in a defined rotational position relative to one or more struts (170) of the standpipe (150); The filtration system of any one of claims 1 to 10, wherein a pocket (186) is disposed in the guide surface (182) that receives the protruding element (32) when the secondary filtration element (10) is at or near a final position.

12. The mutual self-positioning element (30, 180) includes a guide surface (182) and a protruding element (32), the guide surface (182) configured to guide the protruding element (32) from an initial position to a final position in which the secondary filtration element (10) is in a defined rotational position relative to one or more struts (170) of the standpipe (150); The filtration system according to any one of claims 1 to 10, wherein a notch (188) is arranged in the guide surface (182) that receives the protruding element (32) when the secondary filtration element (10) is in a final position.

13. A secondary filtration element (10) for a filtration system (100) according to any one of claims 1 to 12, comprising The secondary filtration element (10) includes a filter medium (16) forming a body (36) having at least one longitudinal seam (18) along a longitudinal axis (L) and an end cap (20) located at a top region (12); the end cap (20) includes one or more connection elements (22) configured to connect the secondary filtration element (10) to a standpipe (150) of the filtration system (100); A secondary filtration element, wherein the end cap (20) has a self-positioning element (30) configured to position the secondary filtration element (10) on the standpipe (150) of the filtration system (100) in a determined rotational position relative to one or more struts (170) of the standpipe (150) of the filtration system (100).

14. A secondary filtration element as described in claim 13, wherein at least one longitudinal seam (18) is a welded seam (18).

15. 15. The secondary filtration element of claim 13 or 14, wherein the end cap (20) of the secondary filtration element (10) has a pot shape and the self-positioning element (30) extends into the interior of the filter media (16).

16. The secondary filtration element of any one of claims 13 to 15, wherein the end cap (20) includes a protruding element (32) extending in an axial direction (L).

17. A secondary filtration element as described in claim 15, wherein the end cap (20) includes a protruding element (32) positioned eccentrically on the end cap (20) relative to a central axis of the end cap (20).

Images