Filter element

Abstract

A filter element having an element material 22 surrounding a cavity 26, which is in the form of a filtration chamber, the element material 22 extending between two end caps 28, 30 arranged at two ends, each of the element materials 22 having a sealing device 32, 34, one of the sealing devices 32 preferably having a polygonal opening cross-section and the other sealing device 34 preferably having a circular opening cross-section, and one of the sealing devices 32 being part of a spherical bearing 44.

Description

Technical Field

[0001] The present invention relates to a filter element comprising an element material with cavities in the form of filter chambers, extending between two end caps arranged at two ends and each having a sealing device.

Background Art

[0002] Patent Document 1 (German Patent Application Publication No. 102018009187) discloses a filter device having a filter housing and a filter element accommodated therein, the element material of which extends between two end caps, and at least one of the two end caps is mounted on an element holder by a spherical bearing providing two or more degrees of freedom such that the filter element is articulated on the element holder via the one end cap. This provides an option to compensate for possible misalignment errors, and during production, a severe reduction in tolerance limits can occur, thus enabling the filter device to be produced reliably and at low manufacturing costs even when using long filter elements or assembled filter housings.

[0003] In known solutions, in the operating position, the filter element is fixed in a manner defined by its lower end cap via a thread, thereby forming a seal within the holder on the housing side, and at the opposite end cap, it is guided by an O-ring seal so as to be movable longitudinally along a nozzle-shaped element holder on the housing head of the filter housing.

[0004] The above-mentioned filter device and the above-mentioned filter element may be subjected to very heavy loads in severe daily operations, for example, when such a solution is used in part of the operation of a hydraulic hammer where the filter element is regularly exposed to strong hydraulic pulsations. In known solutions, one end of the filter element is stationary and fixed in the housing via a thread, which may surely damage the filter element due to the strong pulsations generated especially during the operation of the hammer and the high differential force on the filter element associated therewith.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Therefore, based on this state of the art, the present invention is based on the purpose of further improving the solution method of known filter elements so that the filter element can operate without failure even when it is subjected to high forces, especially when hydraulic pulsations occur.

Means for Solving the Problems

[0007] The filter element having all the features of claim 1 solves this problem. According to the characterizing part of claim 1, one of the sealing devices preferably has a polygonal opening cross-section, the other sealing device preferably has a circular opening cross-section, and the fact that one of the sealing devices is part of a spherical bearing means that any possible misalignment error can still be compensated via the spherical bearing. Furthermore, different from the known case when one end cap is open and the other end cap is closed, via the free opening cross-section of each sealing device, an "open" end cap is created on the element, which results in a reduction of the differential pressure area on the element. The design of the open end cap can significantly minimize any forces that may occur in the axial direction of the element, enabling trouble-free operation even under high loads. This is not equivalent to the prior art. Different opening cross-sections, preferably one being polygonal and the other being circular, provide the only appropriate option for installation, preventing the possibility of incorrect installation when replacing the element with a new one. Furthermore, protection against theft is implemented, both of which bring benefits to reliable operation.

[0008] In a particularly advantageous embodiment, it is provided that the two sealing devices each have an inner circumferential sealing surface that matches each other when viewed in a virtual projection parallel to the longitudinal axis of the filter element. With this design, the possible differential pressure area is further minimized, and as a result, the forces generated during operation cannot damage the filter element, especially the element material, under any circumstances.

[0009] In an even more preferred embodiment of the filter element according to the invention, the spherical bearing has two shell parts, one of the two shell parts is held stationary on one end cap, and the other of the two shell parts is provided with one of the sealing devices and is rotatably held on one of the shell parts. In this way, a greater tolerance can be compensated, allowing for greater geometric variations from one end cap to the other, so there is no longer a need to strictly maintain very tight manufacturing tolerances, which helps to reduce manufacturing costs.

[0010] In this embodiment, it is preferable that one sealing device has an annular groove on its outer periphery with which the inner edge of the other shell part engages. In this way, a spherical bearing with a multi-component structure equipped with one sealing device is achieved, so that in case of failure of the corresponding sealing device, it can be easily and simply replaced with a new sealing device.

[0011] In a further preferred embodiment of the filter element according to the present invention, one sealing device of a polygon forms a regular polygon, preferably a square, on its inner circumference, and the individual wall parts project outwardly convexly with the same curvature between these rounded ends thus formed, and it is provided that the maximum curvature of one of several wall parts is smaller than the minimum curvature of one of the said rounded ends. In this way, the polygonal sealing device is extremely essentially stable and can safely absorb the radial transverse forces without impairing its sealing effect.

[0012] Preferably, this one sealing device has a flat sealing surface on its inner circumference, and this sealing surface is open at the ends along a plurality of inclined parts when viewed in the direction of the longitudinal axis of the filter element. In this way, a defined central sealing surface is generated that provides a seal without the sealing effect being overly determined by other components of the sealing device.

[0013] In a further preferred embodiment of the filter element according to the present invention, the other sealing device is formed from an O-ring seal, and this O-ring seal is preferably enclosed by the sheet metal part of the other end cap and surrounded, especially excluding the exposed sealing surface. Therefore, both sealing devices are designed such that they are guided longitudinally along some guide parts, and as a result, depending on the adjustment of the pressure situation, the element can be positioned at an appropriate position with little force along these guide parts.

[0014] The present invention further relates to a filter device for accommodating the filter element, wherein a guide part having a cylindrical outer peripheral surface for contact with one sealing device is accommodated in one housing part of the filter housing, which is usually in the form of a filter head, and a further guide part having a cylindrical outer peripheral surface for contact with the other sealing device can be detachably connected to this housing part and is accommodated in a further housing part, which is usually in the form of a filter cup. In this way, an essentially stable positioning of the filter element in the housing part of the filter device is achieved by the guide part.

[0015] Preferably, one guide part is formed from a sleeve, along the outside of which one sealing device is guided displaceably in the longitudinal direction, and the other guide part is formed from a cup-shaped insert, which is designed as a locking part and can be locked to the further housing part, and the outer peripheral surface of the insert forms the longitudinal guide part of the other sealing device. By means of the sleeve and the cup-shaped insert described above, a largely turbulence-free fluid flow for filtration by the filter element can be guided through the filter housing.

[0016] In the following, a solution according to the invention will be explained in more detail using one embodiment with reference to the drawings. The following figures are shown as a principle and the scale is not shown as a principle.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Best Mode for Carrying Out the Invention

[0018] The entire filter device is shown in a longitudinal section in FIG. 1. The filter device according to FIG. 1 has a filter head 10 and a filter cup 12 that is removably screwed to the filter head 10 in a known manner. The filter device according to FIG. 1 is shown in its normal vertical operating position, and the filter head 10 is permanently connected to a hydraulic supply circuit (not shown) to carry fluid and is stationary. Further, the filter head 10 has an inlet 14 for the flow of unfiltered medium and an outlet 16 for the filtered flow. Both the inlet 14 and the outlet 16 are connected to the aforementioned hydraulic supply circuit in a normal manner. A spring-biased bypass valve 18 that opens when the filter element in the filter device becomes clogged or blocked is connected between the inlet 14 and the outlet 16, and this bypass valve 18 directly connects the inlet 14 to the outlet 16, bypasses the filter element, and prevents the flow of fluid in the hydraulic supply circuit from being interrupted. Since this type of structure is common to such filter devices, it will not be discussed in more detail here.

[0019] Both the filter head 10 and the filter cup 12 form components of a filter housing 20 in which filter elements are accommodated. The filter elements typically comprise an element material 22 which is preferably pleated in order to increase its filter surface. The element material 22 is supported on its inside by a perforated support tube 24 and thus surrounds a cavity 26 which is also referred to in technical terms as a filtration chamber. Furthermore, the element material extends between two end caps 28, 30 each having sealing devices 32, 34. The filter elements accommodated within the filter device have a radial distance from the inner circumferential side of the filter housing 20, with the result that the respective inner and outer circumferential sides of the filter elements define an unfiltered media chamber 36 within the filter housing 20. This unfiltered media chamber 36 is connected to an inlet 14 in the direction of the filter head 10 via a channel-shaped fluid connection 38 within the filter head 10. On the other hand, the filtration chamber 26 is connected to an outlet 16 for the filtered flow, and a further fluid connection 39 is guided through a bypass valve 18. Thus, the flow through the element material 22 is from the outside to the inside as seen in the direction of FIG. 1, and any particulate contamination present in the fluid flow is reliably cleaned by the element material 22.

[0020] As shown in particular in FIG. 5, one of the sealing devices 32 is designed with a polygonal opening cross-section 40, and as shown in particular in the illustration of FIG. 3, the other sealing device 34 defines a circular opening cross-section 42. As shown in more detail in FIG. 4, one of the sealing devices 32 is part of a spherical bearing 44 for the filter element with its element material 22. As can be seen from FIG. 1, the two sealing devices 32, 34 each have inner circumferential sealing surfaces 46, 48 which match each other when viewed in a virtual cylindrical projection parallel to the longitudinal axis of the filter element. In this way, the effective differential pressure area is minimized and a force-free mounting of the filter element within the filter housing 20 of the filter device is greatly achieved.

[0021] As can be seen from FIG. 4, the spherical bearing 44 has two shell parts 50, 52, one shell part 50 being held stationary on one end cap 28, and the other shell part 52 having a sealing device 32 and being rotatably held on the one shell part 50. When the filter element with the spherical bearing 44 according to FIG. 4 is accommodated in the filter head 10 along the sleeve 54 as can be seen in more detail from FIG. 2, the other shell part 52 is fixed in a predetermined position in the radial direction with respect to the filter head 10, and the one shell part 50 can slide in an articulated manner with more than two degrees of freedom along the convex outer peripheral side of the other shell part 52. In this regard, the convex outer peripheral surface of the other shell part 52 fits exactly to the corresponding concave inner peripheral side of the one shell part 50. In this regard, the filter element having the filter element material 22 is then arranged rotatably on the other shell part 52 when viewed in different angular directions with respect to the longitudinal axis of the filter element, and thus can compensate for any possible misalignment error.

[0022] One of the sealing devices 32 has, as shown in FIG. 4, an annular groove 56 on the outer periphery, in which the inner edge 58 protruding of the other shell part 52 engages. The integrally formed end cap 28 has a sleeve-shaped boundary wall 60 near the bottom, and this boundary wall has a predetermined overhang and protrudes into the filtration chamber 26, that is, has a predetermined radial distance with respect to the inner peripheral side of the support tube 24 in this region. In this regard, the end cap 28 having a cylindrical outer edge and an inner boundary wall 60 forms a trough-shaped receiving space for an adhesive bed 62 (not shown in detail), and this adhesive bed 62 is used to fix the end cap 28 to the ends of the element material 22 and the free end faces of the support tube 24.

[0023] As can be further seen from FIGS. 4 and 5, one of the sealing devices 32 of the polygon forms a square having four corners 64 on the inner circumference, and the individual wall portions 66 project outwardly convexly with the same curvature between these rounded ends 64 thus formed. The seal ring having a polygonal opening cross section has a substantially flat annular sealing surface 68 on the inner circumferential side formed by the ends 64 and the wall portions 66, and this annular sealing surface 68 is open at the ends along the inclined portions 70, 72 as seen in the direction of the virtual longitudinal axis of the filter element. By these inclined portions 70, 72, the actual sealing surface 68 is "cut free", and thus forms a sliding surface in a sealed manner for sliding along the outer circumferential side of the sleeve 54 on the head side, as is particularly apparent from the illustration according to FIG. 2.

[0024] In this way, the upper end cap 28 is guided axially along the sleeve 54 via the spherical bearing 44 and one of the sealing devices 32, and is supported radially accordingly. In this regard, the sleeve 54 is at least in part of a further fluid guide 39 within the filter head 10 and is stationary accommodated in a recess on the head side. In this regard, the sleeve 54 forms a guide portion 74, along the outside of which one of the sealing devices 32 is guided so as to be longitudinally movable. The other sealing device is formed from an elastic O-ring 76 as shown in FIG. 3, and this O-ring is enclosed by the sheet metal portion 78 of the other end cap 30 and is enclosed except for the sealing surface 48 exposed on the inside. In this regard, the other end cap 30 is formed from a shaped sheet metal portion and is a sleeve portion 80 protruding in the direction of the filtration chamber 26. The sleeve portion 80 has a sleeve portion 80 that functions to accommodate a further adhesive bed 82 (not shown) together with the annular outer wall of the end cap 30. By this further adhesive bed 82, the lower end region of the element material 22 and the support tube 24 can be fixed to the other end cap 30 in a defined manner. Further, a further guide portion 84 formed from a cup-shaped insert 86 is provided in this lower end region of the filter element. This further guide portion 84 is designed as a locking portion and is locked at the bottom side with another housing portion in the form of the filter cup 12. The cup-shaped insert 86 has a cylindrical independent outer peripheral surface 88 on the outer peripheral side, and this outer peripheral surface forms a longitudinal guide for the other sealing device 34 shown together with the O-ring seal 76. As can be seen from FIG. 1, the filter element is guided axially on both sides of the filter element along the respective guide portions 74, 84 by the two sealing devices 32, 34, and the filter element can be self-supporting and can be positioned independently according to the pressure within the filter housing 20.

[0025] To prevent oil from being discharged more easily when the filter cup 12 is emptied, the further guide part 84 has a circular notch 85 at the bottom. Since the cup-shaped further guide part 84 is designed to be closed in the direction of the filtration chamber 26, in the normal filter operation, as long as the unfiltered medium does not flow through the element material 22 of the filter element through the support tube 24, the unfiltered medium will not reach the filtration side in this area.

[0026] Also, due to the solution according to the present invention, the filter element enables easy use in so-called hammer operations where it is subjected to high hydraulic pressure loads due to pulsation. The fact that the two open end caps 28, 30 are present on the filter element makes it possible to significantly minimize the effective differential pressure area and thus the axial force. For this purpose, both end caps 28, 30 must be reliably sealed, which is easily possible by means of the aforementioned sealing devices 32, 34. Since one sealing device 32 is fastened (clipped) to the spherical bearing 44 of one end cap 28 and the O-ring 76 of the other sealing device 34 is guided by the sheet metal part 78 of the other end cap 30, there is no need to bond the sealing devices 32, 34, which correspondingly makes the manufacture of the filter element easier and more cost-effective.

Claims

1. In particular, a filter element having an element material (22) that surrounds a cavity (26) which is in the form of a filtration chamber, the element material (22) extending between two end caps (28, 30) located at two ends, and each of the two end caps (28, 30) having a sealing device (32, 34), A filter element characterized in that one sealing device (32) preferably has a polygonal opening cross-section, the other sealing device (34) preferably has a circular opening cross-section, and the one sealing device (32) is part of a spherical bearing (44).

2. The filter element according to claim 1, characterized in that the two sealing devices (32, 34) each have inner circumferential sealing surfaces (46, 48) that fit together when viewed in a virtual projection parallel to the longitudinal axis of the filter element.

3. The filter element according to claim 1, wherein the spherical bearing (44) has two shell portions (50, 52), one of the two shell portions (50) is held stationarily on one of the end caps (28), and the other shell portion (52) has one of the two shell portions (50, 52) and is rotatably held on the one shell portion (50).

4. The filter element according to claim 1, characterized in that one sealing device (32) has an annular groove (56) on its outer circumference, and the other shell portion (52) engages with an inner edge (58) in the annular groove (56).

5. The filter element according to claim 1, wherein the polygonal sealing device (32) has a regular polygon, preferably a square, on its inner circumference, and individual wall portions (66) protrude outward convexly with the same curvature between these rounded endpoints (64) formed in this manner, and the maximum curvature of one of the wall portions (66) is smaller than the minimum curvature of one of the rounded endpoints (64).

6. The filter element according to claim 1, wherein the one sealing device (32) has a flat sealing surface (68) on its inner circumference, and the sealing surface (68) is open at the end along a plurality of inclined portions (70, 72) when viewed in the direction of the longitudinal axis of the filter element.

7. The filter element according to claim 1, characterized in that the other sealing device (34) is formed from an O-seal ring (76).

8. The filter element according to claim 7, characterized in that the O-seal ring (76) is enclosed by the sheet metal portion (78) of the other end cap (30) and surrounded except for the particularly exposed sealing surface (48).

9. A guide portion (74) having a cylindrical outer surface for contact with one of the sealing devices (32) is housed within one of the housing portions (10) of the filter housing (20). A filter device having a filter element according to claim 1, characterized in that a further guide portion (84) having a cylindrical outer surface for contact with the other sealing device (34) is housed in a further housing portion (12) that is detachably connectable to the housing portion (10).

10. One guide portion (74) is formed from a sleeve (54), and the one sealing device (32) is guided along the outside of the sleeve (54) so ​​as to be displaceable in the longitudinal direction. The filter device according to claim 9, characterized in that the other guide portion (84) is formed from a cup-shaped insert (86), the insert (86) is designed as a locking portion and can be locked to the further housing portion (12), and the outer peripheral surface (88) of the insert (86) forms a longitudinal guide for the other sealing device (34).

Images