Pressure equalising device and housing comprising the pressure equalising device

Abstract

A pressure equalising device for a housing, including an inside, an outside, and a lattice-like cage having a gas passage opening. The gas passage opening connects the inside and the outside in a differential pressure-dependent and flow-conducting manner. The gas passage opening is covered by a gas-permeable membrane which includes at least one nonwoven layer. The nonwoven layer includes fibers which are substantially completely sheathed by a sheath of an elastomer.

Claims

1. A pressure equalising device for a housing, comprising: an inside; an outside; and a lattice-like cage having a gas passage opening, wherein the gas passage opening connects the inside and the outside in a differential pressure-dependent and flow-conducting manner, wherein the gas passage opening is covered by a gas-permeable membrane which comprises at least one nonwoven layer, wherein the nonwoven layer comprises fibers which are substantially completely sheathed by a sheath of an elastomer, and wherein the fibers of the nonwoven layer are each individually and completely sheathed.

2. The pressure equalising device as claimed in claim 1, wherein the elastomer is formed by a fluoroelastomer (FKM) blend.

3. The pressure equalising device as claimed in claim 1, wherein the sheath of the elastomer is formed by an elastomer impregnation.

4. The pressure equalising device as claimed in claim 1, wherein the nonwoven layer has a substantially identical air permeability in a temperature range from ?40? C. to +150? C.

5. The pressure equalising device as claimed in claim 1, wherein the nonwoven layer and a further nonwoven layer are arranged in a functional in-series configuration and form a subassembly.

6. The pressure equalising device as claimed in claim 5, wherein the further nonwoven layer is designed as a laminate of nonwoven and expanded polytetrafluoroethylene (ePTFE).

7. The pressure equalising device as claimed in claim 5, wherein the nonwoven layer is arranged on a side of the membrane which faces the inside and the further nonwoven layer is arranged on a side of the membrane which faces the outside.

8. The pressure equalising device as claimed in claim 7, wherein the nonwoven layer and the further nonwoven layer are of substantially congruent design.

9. A housing comprising the pressure equalising device as claimed in claim 1.

10. The housing as claimed in claim 9, wherein the housing encloses electronic components.

11. The pressure equalising device as claimed in claim 1, wherein the nonwoven layer comprises at least a first fiber and a second fiber, wherein the first fiber is sheathed by a first sheath, and wherein the second fiber is sheathed by a second sheath.

12. A pressure equalising device for a housing, comprising: an inside; an outside; and a lattice-like cage having a gas passage opening, wherein the gas passage opening connects the inside and the outside in a differential pressure-dependent and flow-conducting manner, wherein the gas passage opening is covered by a gas-permeable membrane which comprises at least one nonwoven layer, wherein the nonwoven layer comprises fibers which are substantially completely sheathed by a sheath of an elastomer, and wherein the nonwoven layer and a further nonwoven layer are arranged in a functional in-series configuration and form a subassembly.

13. The pressure equalising device as claimed in claim 12, wherein the further nonwoven layer is designed as a laminate of nonwoven and expanded polytetrafluoroethylene (ePTFE).

14. The pressure equalising device as claimed in claim 12, wherein the nonwoven layer is arranged on a side of the membrane which faces the inside and the further nonwoven layer is arranged on a side of the membrane which faces the outside.

15. The pressure equalising device as claimed in claim 14, wherein the nonwoven layer and the further nonwoven layer are of substantially congruent design.

16. A pressure equalising device for a housing, comprising: an inside; an outside; and a lattice-like cage having a gas passage opening, wherein the gas passage opening connects the inside and the outside in a differential pressure-dependent and flow-conducting manner, wherein the gas passage opening is covered by a gas-permeable membrane which comprises at least one nonwoven layer, wherein the nonwoven layer comprises fibers which are substantially completely sheathed by a sheath of an elastomer, wherein the nonwoven layer comprises at least a first fiber and a second fiber, wherein the first fiber is sheathed by a first sheath, and wherein the second fiber is sheathed by a second sheath.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) Two exemplary embodiments of a pressure equalising device according to the invention are explained in more detail below with reference to the schematically illustrated FIGS. 1 and 2.

(2) The pressure equalising devices can be used for all types of housings in which unwanted differential pressures between the inside 1 and the outside 2 are to be avoided. The pressure equalising devices have an inside 1 and an outside 2, wherein the pressure from the interior of a housing acts on the inside 1 and the ambient pressure, usually atmospheric pressure, acts on the outside 2 of the gas-permeable membrane 5.

(3) The pressure equalising devices each comprise a lattice-like cage 3 having the gas passage opening 4, which connects the inside 1 and the outside 2 in a flow-conducting manner as a function of the differential pressure acting on the membrane 5. In both exemplary embodiments, the membrane 5 comprises the porous nonwoven layer 6. The fibers 7 of the nonwoven layer 6 are substantially completely sheathed by the sheath 8 of elastomer 9.

(4) In order to be able to operate the pressure equalising device reliably in a large temperature range, for example from ?40? C. to +150? C., the elastomer 9 in the exemplary embodiments shown here consists in each case of an FKM blend.

(5) FIG. 1 shows a first exemplary embodiment, in which the gas-permeable membrane comprises only the nonwoven layer 6, the fibers 7 of which are sheathed by the sheath 8 consisting of the elastomer 9.

(6) FIG. 2 shows a further exemplary embodiment, which differs from the exemplary embodiment from FIG. 1 in that the gas-permeable membrane 5 is assigned the further nonwoven layer 11.

(7) The nonwoven layer 6 is arranged on the side of the membrane 5 which faces the inside 1 and the further nonwoven layer 11 is arranged on the side of said membrane which faces the outside 2. The further nonwoven layer 11 is designed as a laminate 12 of nonwoven and ePTFE.

(8) In both exemplary embodiments, the nonwoven layer 6 with the fibers 7 sheathed by the sheath 8 of elastomer 9 ensures that oil in its various states is retained on the inside 1, as required, and does not penetrate the gas-permeable membrane 5 in the direction of the outside 2 and thus enter the environment and contaminate it. The elastomer impregnation 10 of the nonwoven layer 6 prevents oil from sticking in the pores of the nonwoven layer 6. Air permeability and thus the function of pressure equalisation between the inside 1 and the outside 2 are thereby ensured at all times.

(9) In FIG. 2, the further nonwoven layer 11 is additionally provided, which is designed as a laminate 12 of nonwoven and ePTFE. This further nonwoven layer 11 prevents the nonwoven layer 6 from being undesirably exposed to large amounts of liquid from the outside 2, which could then penetrate to the inside 1 under unfavorable circumstances.

(10) In the normal case, the further nonwoven layer 11 has no effect on the service properties of the pressure equalising device.

(11) The laminate 12 of nonwoven and ePTFE is used if, in addition to oil repellency with respect to the inside, waterproofness with respect to the outside is also required.

(12) The pressure equalising device according to an embodiment of the invention prevents oil from escaping from the inside 1 through the gas-permeable membrane 5 to the outside 2 over a large temperature range and at the same time ensures excellent pressure equalisation between the inside 1 and the outside 2 during a long service life.

(13) While subject matter of the present disclosure has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. Any statement made herein characterizing the invention is also to be considered illustrative or exemplary and not restrictive as the invention is defined by the claims. It will be understood that changes and modifications may be made, by those of ordinary skill in the art, within the scope of the following claims, which may include any combination of features from different embodiments described above.

(14) The terms used in the claims should be construed to have the broadest reasonable interpretation consistent with the foregoing description. For example, the use of the article a or the in introducing an element should not be interpreted as being exclusive of a plurality of elements. Likewise, the recitation of or should be interpreted as being inclusive, such that the recitation of A or B is not exclusive of A and B, unless it is clear from the context or the foregoing description that only one of A and B is intended. Further, the recitation of at least one of A, B and C should be interpreted as one or more of a group of elements consisting of A, B and C, and should not be interpreted as requiring at least one of each of the listed elements A, B and C, regardless of whether A, B and C are related as categories or otherwise. Moreover, the recitation of A, B and/or C or at least one of A, B or C should be interpreted as including any singular entity from the listed elements, e.g., A, any subset from the listed elements, e.g., A and B, or the entire list of elements A, B and C.