ICE PRESSURE COMPENSATION ELEMENT

Abstract

A compensation element, in particular a filter system, that is configured for volume compensation for a freezing medium. The compensation element includes an elongated hollow body with a first end and a second end, at the first end a coupling area being situated which closes the hollow body, and the second end in particular being open, the compensation element having an elastically reversible design in order to return back to the initial state after a deformation from an initial state that has taken place due to ice formation by the medium, and the hollow body having a cross section with a circumferentially closed outer area, and including an inner structure that is situated at an inner circumference of the outer area.

Claims

1-15. (canceled)

16. A compensation element including a filter system configured for volume compensation for a freezing medium, the compensation element comprising: an elongated hollow body with a first end and a second end, at the first end, a coupling area being situated which closes the hollow body, and the second end being open; wherein the compensation element has an elastically reversible configuration to return back to an initial state after a deformation from the initial state that has taken place due to ice formation by the medium, and wherein the hollow body has a cross section with a circumferentially closed outer area, and includes an inner structure that extends in a longitudinal direction and that is situated at an inner circumference of the outer area.

17. The compensation element as recited in claim 16, wherein the outer area and the inner structure are made of the same material.

18. The compensation element as recited in claim 16, wherein the outer area and the inner structure have a one-piece configuration, as an injection-molded part.

19. The compensation element as recited in claim 16, wherein the inner structure is configured in such a way that a geometric shape of the inner structure remains essentially unchanged in the event of ice formation, and the outer area is configured n such a way that the deformation takes place predominantly or solely at the outer area.

20. The compensation element as recited in claim 16, wherein the inner structure and the outer area have a constant, identical wall thickness.

21. The compensation element as recited in claim 16, wherein the hollow body at the second end includes a radially outwardly directed flange area.

22. The compensation element as recited in claim 16, wherein a pressure compensation element that closes the second end is situated at the second end.

23. The compensation element as recited in claim 16, wherein the hollow body includes protrusions at an outer circumference, adjacent to the second end, that are configured to fix the compensation element.

24. The compensation element as recited in claim 16, wherein the hollow body is cylindrical or truncated cone-like, and the outer area includes a plurality of flat areas that extend in a direction of a center axis of the hollow body.

25. The compensation element as recited in claim 24, wherein the hollow body includes exactly three flat areas at the outer area, and the inner structure includes three wall areas that meet in the center axis of the compensation element and are situated adjacent to one another at an angle of 120°.

26. The compensation element as recited in claim 16, wherein the hollow body has a cylindrical or truncated cone-like configuration, and the inner structure includes three inwardly protruding triangular areas in such a way that the compensation element in an undeformed state includes a tripod cavity with three hollow areas that have the same configuration, and that meet in a center axis of the hollow body and are each offset relative to one another by 120°.

27. The compensation element as recited in claim 16, wherein the hollow body has a cylindrical or truncated cone-like configuration, and the inner structure includes four inwardly protruding triangular areas in such a way that the hollow body in an undeformed state includes a cross-shaped cavity with four hollow areas that meet in a center axis of the hollow body and in each case are spaced apart from one another by 90°.

28. The compensation element as recited in claim 16, wherein the hollow body has a cylindrical or truncated cone-like configuration, and the inner structure has a cross-shaped configuration with four wall areas that are situated at an angle of 90° relative to one another and that meet in a center axis of the hollow body.

29. A compensation element including a filter system configured for volume compensation for a freezing medium, the compensation element comprising: an elongated hollow body with a first end and a second end, at the first end, a coupling area being situated which closes the hollow body, and the second end being open; wherein the compensation element has an elastically reversible configuration to return back to an initial state after a deformation from the initial state that has taken place due to ice formation by the medium, and wherein the hollow body has a cross section with a circumferentially closed outer area, the hollow body including three flat areas at the outer area and three cylindrical areas at the outer area that are situated in alternation along the circumference, and have the same arc length along the circumference of the hollow body, the arc length being 60°.

30. A filter system including a DeNOx filter system, comprising: a compensation element situated inside a filter medium, the compensation element being configured for volume compensation for a freezing medium, the compensation element including: an elongated hollow body with a first end and a second end, at the first end, a coupling area being situated which closes the hollow body, and the second end being open; wherein the compensation element has an elastically reversible configuration to return back to an initial state after a deformation from the initial state that has taken place due to ice formation by the medium, and wherein the hollow body has a cross section with a circumferentially closed outer area, and includes an inner structure that extends in a longitudinal direction and that is situated at an inner circumference of the outer area.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Preferred exemplary embodiments of the present invention are described in greater detail below with reference to the figures.

[0023] FIG. 1 shows a schematic sectional view of a filter system including a compensation element according to a first preferred exemplary embodiment of the present invention.

[0024] FIG. 2 shows a schematic perspective view of the compensation element from FIG. 1.

[0025] FIG. 3A shows a sectional view of the compensation element along line A-A from FIG. 2 in the undeformed initial state.

[0026] FIG. 3B shows a sectional view corresponding to FIG. 3A in the deformed state.

[0027] FIG. 4A shows a sectional view of a compensation element according to a second exemplary embodiment of the present invention in the initial state.

[0028] FIG. 4B shows a sectional view corresponding to FIG. 4A in the deformed state.

[0029] FIG. 5A shows a sectional view of a compensation element according to a third exemplary embodiment of the present invention in the initial state.

[0030] FIG. 5B shows a sectional view corresponding to FIG. 5A in the deformed state.

[0031] FIG. 6A shows a sectional view of a compensation element according to a fourth exemplary embodiment of the present invention in the initial state.

[0032] FIG. 6B shows a sectional view corresponding to FIG. 6A in the deformed state.

[0033] FIG. 7A shows a sectional view of a compensation element according to a fifth exemplary embodiment of the present invention in the initial state.

[0034] FIG. 7B shows a sectional view corresponding to FIG. 7A in the deformed state.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0035] A gas-filled compensation element 1 and a filter system 100 according to a first preferred exemplary embodiment of the present invention are described in greater detail below, with reference to FIGS. 1, 2, 3A, and 3B.

[0036] FIG. 1 shows a schematic sectional view of filter system 100, which is used in a system for liquid urea solutions for catalytic reduction of nitrogen oxides in the field of internal combustion engines (DeNOx). However, the filter system is suited for all fluid media, in particular also water and aqueous solutions, which are able to freeze.

[0037] As is apparent from FIG. 1, filter system 100 has a design with a cup-like filter housing 101 and a cover 102. A filter medium 103 is situated inside filter housing 101. Compensation element 1 is situated inside filter medium 103. Filter system 100 also includes a retaining ring 104, which in particular retains filter medium 103. In addition, a pressure compensation element 105, which acts as a valve to allow a gas exchange between an inner space of the compensation element and a surroundings side, is situated in cover 102. Filter medium 103 may be part of a replaceable filter element (in the present case, without a reference numeral), which among other things includes retaining ring 104 (as a type of upper or first end cap) and often also a lower or second end cap (in the present case, also without a reference numeral). Filter medium 103 may be a filter paper, for example, such as a filter paper folded in a star shape, or may be made of melt-blown material.

[0038] As is apparent from FIG. 1, compensation element 1 is fixed in filter system 100 only on one side. If ice formation should occur inside filter system 100, compensation element 1 is elastically reversibly deformed in order to provide a volume compensation for the freezing medium in filter system 100.

[0039] After ice formation in filter system 100, which results in an increase in volume of the freezing medium, compensation element 1 may thus undergo a deformation, it being possible for the gas situated inside compensation element 1 to be emitted to the surroundings via pressure compensation element 105.

[0040] Compensation element 1 is apparent in the detail from FIGS. 2, 3A, and 3B. Compensation element 1 includes an elongated hollow body 2 which has an essentially hollow cylindrical, or alternatively a hollow truncated cone-like, design. Hollow body 2 includes a first end 21 and a second, open end 22.

[0041] A closure cap 5 that closes the inner cavity of hollow body 2 is situated at first end 21. Second end 22 has an open design, strictly as an example here, in order to provide a gas connection to pressure compensation element 105.

[0042] FIGS. 3A and 3B each show a cross section along line A-A from FIG. 2. FIG. 3A shows the undeformed state of compensation element 1, and FIG. 3B shows a maximally deformed state of compensation element 1 after ice formation at the outer circumference of compensation element 1.

[0043] As is apparent from FIG. 3A, hollow body 2 includes a circumferentially closed outer area 3 and an inner structure 4 that extends in the longitudinal direction of the hollow body.

[0044] Inner structure 4 is situated inside outer area 3, and has a one-piece design with outer area 3. Outer area 3 and inner structure 4 are thus made of the same material, preferably with the aid of an injection molding process.

[0045] Outer area 3 in principle has a hollow cylindrical shape, or alternatively, a shape of a hollow truncated cone, outer area 3 including multiple flat areas 30. As is apparent from FIG. 3A, this results in a design such that flat areas 30 and cylindrical areas 31 alternate along the circumference of outer area 3. In this exemplary embodiment, exactly three flat areas 30 and three cylindrical areas 31 are provided. Flat areas 30 are formed over an angle α of 60° along the outer circumference of the outer area, and cylindrical areas 31 are formed along an angle β of likewise 60° along the outer circumference of the outer area.

[0046] Inner structure 4 includes exactly three wall areas 41 which meet in a center axis X-X of compensation element 1. A core area 42 having a circular cross section is situated in center axis X-X, as the result of which the connection between wall areas 41 is reinforced. Wall areas 41 are uniformly situated along the circumference at an angle of 120° in each case, and extend up to the level of closure cap 5.

[0047] As is further apparent from FIG. 3A, wall areas 41 contact outer area 3 at the inner side of cylindrical areas 31. There is no contact between inner structure 4 and flat areas 30 of outer area 3.

[0048] FIG. 3B explains the compressed state of compensation element 1 in the event of ice formation at the outer circumference of hollow body 2. The compressed hollow body is denoted by reference numeral 2′ in FIG. 3B. As is apparent from FIG. 3B, inner structure 4 of compensation element 1 remains unchanged, i.e., without deformation. Outer area 3 deforms in particular at flat areas 30, which are not in contact with inner structure 4. At maximum deformation, which is illustrated in FIG. 3B, flat areas 30 may deform until they make contact with core area 42. Cylindrical areas 31 are likewise deformed; however, due to the curvature of the cylindrical areas, direct contact between deformed cylindrical areas 31 and inner structure 4 is prevented from occurring, in particular at the attachment area between inner structure 4 and outer area 3. In particular, an irreversible adhesion of deformed cylindrical areas 31 to inner structure 4 is thus prevented.

[0049] As illustrated in FIG. 1, inner structure 4 is connected to closure cap 5 via a rod-shaped connection 40, which in this exemplary embodiment is a short cylindrical section. In this exemplary embodiment, the configuration is such that flat areas also include a small portion 30a that is formed at closure cap 5 (cf. FIG. 2). In the event of ice formation, coupling area 5 is thus also deformed slightly, so that excessively large stresses between deformed outer area 3 and closure cap 5 may be avoided.

[0050] As is further apparent from FIGS. 1 and 2, a flange area 6 is provided at open end 22 of hollow body 2. Flange area 6 extends circumferentially and radially outwardly from hollow body 2. Flange area 6 is used in particular to fix compensation element 1 to filter system 100.

[0051] As is apparent from FIG. 2, multiple protrusions 7 are provided at outer area 3. A groove 8 is provided between protrusions 7 and flange area 6. In this exemplary embodiment, three protrusions 7 are situated at the outer circumference of outer area 3, protrusions 7 being situated in the region of cylindrical areas 31.

[0052] As is apparent from FIG. 1, a connection with retaining ring 104 at groove 8 is established by clipping in. Compensation element 1 is thus clamped to retaining ring 104 on one side. First end 21 is freely positioned in filter system 100.

[0053] It is noted that for secure sealing between an inner space of filter system 100 and the surroundings, additional sealing elements, for example O-rings or the like, may also be provided at second end 22.

[0054] The material of one-part compensation element 1 is preferably EPDM.

[0055] FIGS. 4A and 4B show a compensation element 1 according to a second exemplary embodiment of the present invention. Identical or functionally equivalent parts are denoted by the same reference numerals as in the preceding exemplary embodiment.

[0056] The second exemplary embodiment corresponds essentially to the first exemplary embodiment, compensation element 1 including a hollow body 2 that includes only an outer area 3. Hollow body 2 of the second exemplary embodiment thus includes no inner structure. Outer area 3 is designed as in the first exemplary embodiment, with three flat areas 30 and three cylindrical areas 31. The completely deformed state is illustrated in FIG. 4B.

[0057] FIGS. 5A and 5B show a third exemplary embodiment of the present invention, identical or functionally equivalent parts being denoted by the same reference numerals as in the preceding exemplary embodiments.

[0058] As is apparent from FIG. 5A, hollow body 2 includes a cylindrical outer area 3, and three triangular areas 43 as inner structure 4. Triangular areas 43 extending in the longitudinal direction have a triangular shape with a curved side situated at the inner circumference of outer area 3, and two straight sides having an angle of 120° between them. The three triangular areas 43 are uniformly distributed along the inner circumference of outer area 3, and have a one-piece design with outer area 3. This results in three hollow areas 33 inside hollow body 2, which meet in center axis X-X. This results in a tripod cavity inside hollow body 2 in the undeformed state of compensation element 1. FIG. 5B shows the compressed state during ice formation, hollow body 2′ being compressed in such a way that the three triangular areas 43 remain undeformed, and the deformation takes place solely at outer area 3 situated between the three triangular areas 43. The three triangular areas 43 may touch one another in the completely deformed state.

[0059] FIGS. 6A and 6B show a compensation element 1 according to a fourth exemplary embodiment of the present invention. Identical or functionally equivalent parts are once again denoted by the same reference numerals as in the preceding exemplary embodiments.

[0060] As is apparent from FIG. 6A, hollow body 2, similarly as for the third exemplary embodiment, includes a cylindrical outer area 3, and four triangular areas 44 as inner structure 4. The four triangular areas 44 extending in the longitudinal direction are adjacently situated at an angle γ of 90° in each case. Similarly as for the third exemplary embodiment, triangular areas 44 have a triangular shape with a curved side that is in contact with the inner circumference of outer area 3 and that has a one-piece design with outer area 3. The other two sides of triangular area 44 have a straight design and form a right angle between them. This results in a cavity inside hollow body 2 which includes four hollow areas 34 that meet at center axis X-X of compensation element 1. As illustrated in the completely compressed state in FIG. 6B, the four hollow areas 34 completely disappear when hollow body 2 is compressed by ice formation. A very intense deformation occurs in the outer area, at whose inner side the four hollow areas 34 are formed.

[0061] FIGS. 7A and 7B show a compensation element 1 according to a fifth exemplary embodiment of the present invention. Identical or functionally equivalent parts are once again denoted by the same reference numerals as in the preceding exemplary embodiment.

[0062] The fifth exemplary embodiment includes a hollow body 2 with a cylindrical outer area 3 and inner structure 4, designed as a cross, extending in the longitudinal direction. Inner structure 4 once again has a one-piece design with outer area 3. Inner structure 4 includes four wall areas 41 that are each situated at a right angle relative to one another. This results in four hollow areas 35 that are in contact with one another only at the respective ends of hollow body 2. At maximum deformation, illustrated in FIG. 7B, only slight deformations of compensation element 1 result, since compensation element 1 is very rigid due to cross-shaped inner structure 4. This results in a slight compression of inner structure 4 in the area of center axis X-X of compensation element 1. In comparison to the preceding exemplary embodiments, a compensation function of the fifth exemplary embodiment in the event of ice formation is thus reduced.