Pressure balancing membrane

Abstract

The invention relates to a pressure equalizing membrane (11) comprising a membrane (1), characterized in that the membrane (1) is sandwiched by a reinforcing edge (4).

Description

TECHNICAL FIELD

[0001] The present invention relates to a pressure equalization membrane for attaching to a surface of an article, such as a housing containing electronic components, at a pressure equalization opening. BACKGROUND

[0002] Many engineering devices, for example in the field of vehicles, buildings and houses, comprise housings, usually equipped with seals, containing electronic components and therefore must be completely sealed to avoid damaging the electronic components, thus prolonging the useful life of the device. By way of example, a housing can be involved of earthmoving equipment, road construction equipment, cranes, forklifts, tractors or any other agricultural vehicle. It can also be a sealed housing of a car headlight or of an external spotlight, for example to illuminate a garden or a monument.

[0003] It is known to provide one or several openings, so-called "pressure equalization openings", in these housings.

[0004] In fact, temperature variations during the day, the season or the altitude, even due to the heat generated by the device itself during its operation, cause pressure differences inside the sealed housing. A sudden drop in temperature generates a vacuum inside the housing. If this pressure difference is not eliminated, the vacuum exerts a constant tension on the seals of the housing that ensure its sealing. Over time, this causes the seals to wear, allowing moisture and other contaminants, such as dust, dirt, to enter the housing, damaging and / or oxidizing the electronic components.

[0005] Therefore, these pressure equalization openings are necessary to allow the air inside the housing to expand, to be expelled in the case of a temperature increase or to flow in the case of cooling.

[0006] For example, the electronic components of a car, designed in particular to control the parameters of the car, generate heat during operation, which not only causes self-heating of the electronic components, but also heats the air inside the housing. Thanks to these pressure equalization openings, in the absence of pressure equalization, an overpressure could occur inside the housing, reaching 300, 500 or 700 millibars depending on the environmental temperature and the intensity of use of the electronic components, in other words their electrical power consumption.

[0007] In addition, the presence of moisture inside a sealed housing can cause serious damage to the device. In fact, when water vapor enters a sealed housing and has no way to escape, it condenses into a liquid. If this condensed liquid remains inside the sealed housing, there is a risk of damaging the proper functioning of the electronic components, in particular by oxidizing them.

[0008] Finally, the pressure equalization openings must not be exposed to dirt (dust, wind-borne particles), rain, external agents (for example insects, gravel, sand) so as not to damage the electronic components inside the sealed enclosure.

[0009] For all these reasons, it is known to cover these openings with pressure equalization membranes.

[0010] These pressure equalization membranes are therefore intended to:

[0011] - allow gas exchange, thus equalizing the pressure inside the enclosure (depending on different climatic events or operating conditions of the enclosure elements or more generally of the device in which the enclosure is integrated), and to reduce condensation inside the enclosure which would oxidize sensitive electronic components,

[0012] - prevent dirt (for example particles carried by the wind or dust), water, humidity, mold, external agents (insects, gravel, sand) from entering the enclosure, thus not damaging the electronic components, so that the electronic components can operate reliably and durably whatever the use conditions of the device comprising said enclosure.

[0013] In addition, in the case where the enclosure contains a battery, its charging cycle generates heat and releases hydrogen gas or other gases. This can lead to an explosion. The pressure equalization membrane effectively eliminates these gases. Thus, by continuously equalizing the pressure inside the enclosure, this membrane reduces the risk of explosion.

[0014] In other words, these pressure equalization membranes are designed to protect electronic components in the most hostile environments and conditions. They combine gas (especially air) permeability, while protecting electronic components from various external agents and contaminants (dirt, dust, water, humidity, insects, sand, gravel, etc.) described above.

[0015] More particularly, as regards the gas permeability, these membranes offer a compact ventilation structure, easy to install and integrate on a device (for example on an enclosure comprising electronic components).

[0016] The pressure equalization membranes are designed to quickly equalize pressure variations inside a sealed enclosure, effectively preventing the internal vacuum or pressure build-up described above, which would:

[0017] - pressurize the seals of the sealed enclosure and prematurely damage them,

[0018] - attract the external contaminants described above inside the sealed enclosure.

[0019] These pressure equalization membranes must therefore have sufficient mechanical strength to withstand adverse weather, the external contaminants described above (in particular gravel) and the pressure fluctuations described above.

[0020] The reliable and durable pressure equalization membrane prolongs the service life of the device, thus reducing the maintenance costs.

[0021] To ensure all these functions listed above, the pressure equalization membrane is usually made of a microporous film of polymeric material, preferably polytetrafluoroethylene, hereinafter referred to as "PTFE". This film of polymeric material has enough micropores to allow the exchange of gas, in particular air, through the membrane, while presenting a certain sealing and solidity to prevent the passage of liquids or other aforementioned contaminants (dirt, sand, gravel, insects) through the membrane. The thickness of this membrane made of PTFE is in the range of 300 pm.

[0022] However, PTFE has the disadvantage that it is an expensive material, not recyclable, its production requires toxic and harmful materials, and when heated it produces greenhouse gases or toxic products. Therefore, in order to limit the cost and environmental impact of the pressure equalization membrane without reducing its solidity and its gas permeability and liquid sealing functions, it is known to limit the amount of PTFE by providing a double membrane with:

[0023] - a first layer of PTFE film with a reduced thickness compared to a single layer of PTFE membrane, i.e. from 20 pm to 30 pm,

[0024] - a second layer of textile material (thickness of about 100 pm) which has been attached to the first layer of PTFE film, for example, by a plurality of glue points (thickness of about 10 pm).

[0025] In this embodiment, it is known to the person skilled in the art that the pressure equalization membrane must be attached to the pressure equalization opening leading to the sealed space of the device in such a way that:

[0026] - the second layer of textile material faces the sealed space, and

[0027] - the first layer of PTFE film faces the outside of this sealed space.

[0028] In this way, when the pressure equalization membrane is subjected to severe external conditions (for example weather: heavy rain) or comes into contact with external factors (for example gravel), the textile material does not risk peeling off or tearing off from the PTFE film layer.

[0029] However, this embodiment is not entirely satisfactory because the first layer of PTFE film is thinner, so it is more easily damaged than a single layer of PTFE film. For example, in the case of the housing of an automotive headlight, the membrane is more easily worn, scratched or impacted. This will reduce its sealing, thus reducing the sealing of the housing and affecting the service life of the device.

[0030] Finally, the pressure equalization membrane is generally provided on the entire periphery of the face opposite the confined space of the device, with a layer for attachment to the device. This attachment device is generally in the form of a frame whose outer edge corresponds to the periphery of the membrane and which comprises a face covered with adhesive to enable attachment of the membrane at the pressure equalization opening. Thus, a large part of the surface of the membrane, i.e. its entire periphery, is covered by the attachment device and thus does not contribute to the gas exchange described above. In other words, a large part of the pressure equalization membrane is “sacrificed” to allow its attachment to the device.

[0031] US patent application 2014 / 0283691 A1 describes a sealed vent structure comprising a housing having an opening and a gas-permeable sealing membrane covering the opening. A space inside the housing and a space outside the housing are in communication with each other through the opening covered by the membrane. The membrane comprises two layers of material. Double-sided adhesive is used as a means of attaching the membrane on the one hand to the housing and on the other hand to the electronic components contained by the housing to be protected. These double-sided adhesives are flush with the membrane. None of these adhesives protrude beyond the periphery of the membrane.

[0032] US patent 9,875,733 B2 describes a vent device comprising a membrane divided into a central portion and a peripheral portion surrounding said central portion. The peripheral portion is adhered:

[0033] - to a foam lamination layer having an adhesive face at a first face of the membrane;

[0034] and

[0035] - to a double-sided adhesive polyester film at a second face of the membrane.

[0036] The lamination layer and the double-sided adhesive polyester film sandwich the membrane flush around its entire periphery.

[0037] In summary, the pressure equalization membranes known to date have various drawbacks (depending on their different embodiments detailed above), in particular the expensive and non-ecological nature of PTFE, the lack of robustness in the face of bad weather or external factors (gravel), the risk of tearing or loss of sealing. SUMMARY

[0038] The inventors of the present invention sought to overcome these drawbacks and have developed a pressure equalization membrane having the following advantages:

[0039] - said membrane can comprise a reduced amount of PTFE, thereby reducing its economic and environmental impact;

[0040] - excellent durability;

[0041] - excellent resistance to harsh climatic conditions and to the operating conditions of the device in which the membrane is incorporated, and to the aforementioned external factors (gravel, dust, etc.).

[0042] The present application thus relates to a pressure equalizing membrane comprising a membrane and a reinforcing rim, a part or all of the perimeter of the membrane being clamped by the reinforcing rim comprising a first element and a second element,

[0043] The first element and the second element each comprise a support layer,

[0044] The support layer of the first element has a first face and a second face,

[0045] The support layer of the second element has a first face and a second face,

[0046] The pressure equalizing membrane is characterized in that:

[0047] - a part of the second face of the support layer of the second element is attached to a part of the first face of the support layer of the first element, the remaining part of the second face of the support layer of the second element is attached to a part of the membrane, and the remaining part of the first face of the support layer of the first element is attached to a part of the membrane

[0048] or

[0049] - the entire second face of the support layer of the second element is attached to the membrane, and a part of the first face of the support layer of the first element is attached to the membrane.

[0050] The first face of the support layer of the second element of the reinforcing rim is intended to be attached to a device provided with a restricted space opening to a pressure equalizing opening, so that the pressure equalizing membrane according to the application covers the opening of the device.

[0051] The second face of the support layer of the first element of the reinforcing rim is intended to be in contact with the environment external to the restricted space opening to a pressure equalizing opening, covered by the pressure equalizing membrane according to the application.

[0052] In an embodiment of the application, in which the entire second face of the support layer of the second element is attached to the membrane, and a part of the first face of the support layer of the first element is attached to the membrane, the remaining part of the first face of the support layer of the first element of the reinforcing rim is intended to be attached to the device, more precisely around the perimeter of the pressure equalizing opening provided to the device.

[0053] Preferably, the entire perimeter of the membrane is clamped with the reinforcing rim.

[0054] In one embodiment of the application, a part of the perimeter of the membrane is clamped with the reinforcing rim. Preferably, more than 20%, more preferably more than 50% of the perimeter of the membrane is clamped with the reinforcing rim.

[0055] In the context of the present invention, the term "clipping a part or all of the perimeter of the membrane with a reinforcing edge comprising a first element and a second element" means that the membrane is located between the first element and the second element. According to an embodiment of the present invention, both the first element and the second element can protrude from the perimeter of the membrane, or according to other embodiments of the present invention, only the first element can protrude from the perimeter of the membrane, while the second element will be flush with the perimeter of the membrane. What is common to all these embodiments of the present invention is that the membrane is always located between the first element and the second element, and is therefore well clipped by the reinforcing edge.

[0056] Clipping the membrane with a reinforcing edge has the advantage that the reinforcing edge not only reinforces the membrane and therefore makes it more resistant to harsh weather conditions or external aggressions (such as gravel) that could damage it and / or tear it off, but also makes it possible to reduce the necessary amount of membrane. Indeed, thanks to the clipping of the membrane with a reinforcing edge, it is no longer necessary to "sacrifice" a large part of the membrane to allow its attachment to the device. Indeed, a part of the reinforcing edge contributes to the attachment of the pressure equalizing membrane according to the invention to the device.

[0057] The pressure equalizing membrane according to the present invention comprises a membrane, for example a membrane known from the prior art, examples of which have been described in detail above.

[0058] The membrane can therefore exhibit the following non-limiting technical features.

[0059] The membrane can have any geometric shape. For example, the membrane can be square, rectangular, oval, circular, triangular or any other polygonal shape.

[0060] The surface of the membrane can be between 0.1 cm 2 and 100 cm 2 , preferably between 1 cm 2 and 30 cm 2 .

[0061] The thickness of the membrane can be between 20 pm and 2 mm.

[0062] The membrane can comprise at least one microporous material having a gas permeability measured by the air flow rate passing through the membrane (between 10 and 10 000 mL / min / cm 2 at a pressure of +70 mbar.

[0063] The membrane can be single-layer or multi-layer. If it is multi-layer, it is preferably double-layer.

[0064] In embodiments of the application, the membrane comprises at least one microporous film of a polymeric material. It can be a polymeric material selected from polymers having a low surface energy, preferably less than 40 mN / cm. The polymeric material can be selected from PTFE, polychlorotrifluoroethylene (hereinafter referred to as "PCTFE"), polyvinyl fluoride (hereinafter referred to as "PVF"), polysiloxane, polycarbonate (hereinafter referred to as "PC") and polyester. The microporous film of polymeric material preferably has pores of a size of between about 0.01 μιη and about 50 μιη. Most preferably, the polymeric material of the membrane is PTFE.

[0065] In the context of the present application, the film of polymeric material is microporous in order to allow the above-mentioned gas exchange through the membrane.

[0066] In embodiments of the application, the membrane is monolayered and comprises a microporous film of a polymeric material, preferably of a polymeric material as described above. In other words, the membrane is a microporous film of a polymeric material selected from PTFE, PCTFE, PVF, polysiloxane, PC and polyester, in a single layer. In these embodiments of the application, the thickness of the membrane can be between 20 μιη and 2 mm.

[0067] Examples of such monolayered membranes are in particular the membranes sold under the trade name MV72040 by the company MICROVENT, the membranes sold under the trade name AVS 9 by the company GORE and the membranes sold under the trade name M40W by the company BERGHOF.

[0068] In other embodiments of the application, the membrane is bilayered and comprises a microporous film layer of a first polymeric material, for example a polymeric material as described above, and a second fabric material layer attached to the microporous film layer of the first polymeric material.

[0069] The fabric material can be selected from fabrics based on polyethylene terephthalate (hereinafter referred to as "PET"), polyamide, polypropylene, polyethylene, acrylic, PTFE, elastane, glass fibre, carbon or cellulose. Preferably, these are fabrics based on PET or polyamide. The fabric material can be obtained by a weaving process or by agglomerating fibres or yarns, such as non-woven fabrics and felts.

[0070] Thus, in one embodiment of the application, the membrane is bilayered and comprises a microporous film layer of a first polymeric material selected from PTFE, PCTFE, PVF, polysiloxane, PC and polyester, and a second fabric material layer attached to the microporous film layer of the first polymeric material, the fabric material being selected from fabrics based on PET, polyamide, polypropylene, polyethylene, acrylic, PTFE, elastane, glass fibre, carbon or cellulose.

[0071] In this embodiment of the application, the thickness of the microporous film layer of the first polymeric material can be between 10 μιη and 500 μιη and the thickness of the second textile material layer can be between 10 μιη and 1990 μιη.

[0072] The second textile material layer can be attached to the microporous film layer of the first polymeric material with a glue suitable for bonding between the textile material and the polymeric material (for example: a cyanoacrylate-based glue or a hot-melt glue or a hot reactivatable glue) or with another attachment means consisting of heat-sealing the textile material and the polymeric material. The second textile material layer is advantageously attached to a portion of the microporous film layer of the first polymeric material, thus always allowing the above-mentioned gas exchange through the membrane. In other words, the means for attaching the textile material and the polymeric material film are suitably selected so as not to hinder the gas exchange through the membrane. This selection is entirely within the capabilities of the person skilled in the art.

[0073] These embodiments of the application in which the membrane is a double-layer membrane have the advantage of reducing the cost and the environmental impact of the pressure equalization membrane. Indeed, the membrane comprises a reduced amount of microporous film of polymeric material (preferably PTFE), which is generally expensive, and the synthesis method thereof has an environmental impact.

[0074] Examples of such double-layer membranes are in particular the membrane sold by the company PARKER under the trade name QBV657D, the membrane sold by the company BERGHOF under the trade name M100WL and the membranes sold by the company DONALDSON under the trade names EN0711066 and EN0701435.

[0075] In other possible embodiments of the application, the membrane comprises more than 2 layers of material. For example, it can be a film of alternating layers of polymeric material and textile material.

[0076] The first element and the second element of the reinforcing rim can each have a frame shape, the opening of which has a shape similar to the perimeter of the membrane.

[0077] In one embodiment of the application, the outer dimensions of the frame of the first element and of the second element of the reinforcing rim can be identical.

[0078] In another embodiment of the application, the outer dimensions of the frame of the first element of the reinforcing rim can be greater than the outer dimensions of the frame of the second element of the reinforcing rim. In this embodiment, the portion of the first element opposite the face intended to be in contact with the outside environment will be intended to be attached on the perimeter of the pressure equalization opening, the device being provided with a pressure equalization opening.

[0079] The thickness of the first element of the reinforcing rim can be between 20 μιη and 500 μιη.

[0080] The thickness of the second element of the reinforcing rim can be between 30 pm and 500 pm.

[0081] In one embodiment of the application:

[0082] - the first element of the reinforcing rim can cover from 5% to 60% of the surface of the membrane,

[0083] - the second element of the reinforcing rim can cover from 5% to 70% of the surface of the membrane,

[0084] - the second element of the reinforcing rim can cover from 0% to 90% of the surface of the first element of the reinforcing rim.

[0085] As mentioned above, the second element of the reinforcing rim can be flush with the perimeter of the membrane. In this case, the first element of the reinforcing rim does not cover the second element, in other words the coverage of the second element by the first element is 0%.

[0086] The percentage of the membrane covered by the first element of the reinforcing rim is suitably chosen to reinforce the pressure equalization membrane according to the application so that it is not torn and / or damaged when it is subjected to harsh weather conditions and / or contact with external elements such as gravel.

[0087] The percentage of the membrane covered by the second element of the reinforcing rim is suitably chosen to allow the pressure equalization membrane according to the application to be well attached at the pressure equalization opening of the device. Furthermore, in an embodiment of the application, the outer dimensions of the frame of the first element of the reinforcing rim are greater than the outer dimensions of the frame of the second element of the reinforcing rim, the first element also contributing to the attachment of the pressure equalization membrane according to the application at the pressure equalization opening of the device.

[0088] The percentage of the first element of the reinforcing rim covered by the second element of the reinforcing rim is suitably chosen to ensure good reinforcement of the membrane clamped between the first and second elements of the reinforcing rim. Indeed, the assembly constituted by the portions of the first element of the reinforcing rim and the portions of the second element of the reinforcing rim in contact with each other constitutes good reinforcement of the pressure equalization membrane according to the application.

[0089] Advantageously, the percentage of the membrane covered by the second element of the reinforcing rim is greater than the percentage of the membrane covered by the first element of the reinforcing rim. This allows the pressure equalization membrane according to the application to be attached very well at the perimeter of the pressure equalization opening of the device by the second element of the reinforcing rim.

[0090] Between 0.5 mm and 20 mm, preferably between 1 mm and 10 mm, more preferably between 1 mm and 5 mm of the film can be covered by the first element of the reinforced edge on all or part of the perimeter of the film. This means that, when the film is for example rectangular shaped, between 0.5 mm and 20 mm of the film can be covered by the first element of the reinforced edge on all or part of the width of the film and on all or part of the length of the film.

[0091] Between 0.5 mm and 20 mm, preferably between 1 mm and 10 mm, more preferably between 1 mm and 5 mm of the first element of the reinforced edge can protrude on all or part of the perimeter of the film. This means that, when the film is for example rectangular shaped, between 0.5 mm and 20 mm of the first element of the reinforced edge can protrude on all or part of the width of the film and on all or part of the length of the film.

[0092] Between 0.5 mm and 20 mm, preferably between 1 mm and 10 mm, more preferably between 1 mm and 5 mm of the film can be covered by the second element of the reinforced edge on all or part of the perimeter of the film.

[0093] Between 0.5 mm and 20 mm, preferably between 1 mm and 10 mm, more preferably between 1 mm and 5 mm of the second element of the reinforced edge can protrude on all or part of the perimeter of the film.

[0094] The material of the support layer of the first and second elements of the reinforced edge can be chosen among PET, polyethylene naphthalate (abbreviation “PEN”), polyvinyl chloride (abbreviation “PVC”), polyamide, polypropylene and metal foil. The material of the support layer of the first element can be the same or different from the material of the support layer of the second element.

[0095] The thickness of the support layer of the first element of the reinforced edge can be between 15 pm and 200 pm, preferably between 30 pm and 100 pm.

[0096] The thickness of the support layer of the second element of the reinforced edge can be between 15 pm and 200 pm, preferably between 30 pm and 100 pm.

[0097] The support layer of the first element can have a Young’s modulus (measured according to ISO 527 standard) comprised between 0.5 GPa and 200 GPa, preferably between 1 GPa and 100 GPa, for example 5 Gpa.

[0098] The support layer of the second element can have a Young’s modulus (measured according to ISO 527 standard) comprised between 0.5 GPa and 200 GPa, preferably between 1 GPa and 100 GPa, for example 5 Gpa.

[0099] The support layer of the first element can have an elasticity greater than 10 MPa, preferably greater than 50 MPa, for example 110 MPa, i.e. the force to obtain an elongation of 5% (measured according to the ISO 527 standard).

[0100] The support layer of the second element can have an elasticity greater than 10 MPa, preferably greater than 50 MPa, for example 110 MPa, i.e. the force to obtain an elongation of 5% (measured according to the ISO 527 standard).

[0101] The physical properties of the support layers of the first and second elements are suitably chosen so that the reinforcing edge reinforces the membrane, as described above.

[0102] In an embodiment of the application, the first face of the support layer of the first element of the reinforcing edge and the second face of the support layer of the second element of the reinforcing edge can be covered with an adhesive.

[0103] A portion of the second face of the support layer of the second element of the reinforcing edge can be glued to a portion of the first face of the support layer of the first element of the reinforcing edge, and the remaining portion of the second face of the support layer of the second element of the reinforcing edge can be glued to a portion of the membrane, and the remaining portion of the first face of the support layer of the first element of the reinforcing edge can be glued to a portion of the membrane.

[0104] Alternatively, the entire second face of the support layer of the second element of the reinforcing edge can be glued to the membrane, and a portion of the first face of the support layer of the first element of the reinforcing edge can be glued to the membrane. The remaining portion of the first face of the support layer of the first element of the reinforcing edge will be intended to be attached to the device on the periphery of the pressure equalization opening, the device being provided with this pressure equalization opening.

[0105] The adhesive can advantageously be chosen from pressure-sensitive adhesives, for example chosen from adhesives based on acrylic resins, silicone resins, rubber or polyurethane.

[0106] The adhesive can optionally be dyed, for example by incorporating a pigment or a dye, so that the first and second elements of the reinforcing edge have the same color or a color similar to that of the membrane.

[0107] The thickness of the adhesive can be between 5 pm and 500 pm, preferably between 25 pm and 100 pm.

[0108] The first face of the support layer of the second element of the reinforcing edge can also be covered with an adhesive. This allows the pressure equalization membrane according to the application to be attached to the device in a manner covering the pressure equalization opening of the device. The first face of the support layer of the second element of the reinforcing edge is attached to the device around the periphery of the pressure equalization opening.

[0109] The adhesive can advantageously be chosen from pressure-sensitive adhesives, for example chosen from adhesives based on acrylic resins, silicone resins, rubber or polyurethane.

[0110] The thickness of the adhesive can be between 5 pm and 500 pm, preferably between 25 pm and 100 pm.

[0111] In other embodiments of the application, the first face of the support layer of the second element of the reinforcing rim is free of adhesive. In these embodiments, an adhesive can be present around the periphery of the pressure equalization opening of the device, so as to attach the first face of the support layer of the second element of the reinforcing rim on this adhesive. The adhesive can advantageously be chosen from pressure-sensitive adhesives, for example chosen from adhesives based on acrylic resins, silicone resins, rubber or polyurethane.

[0112] In other embodiments of the application, the entire first face of the support layer of the second element of the reinforcing rim can be attached to the periphery of the pressure equalization opening by heat welding.

[0113] In one embodiment of the application, a portion of the second face of the support layer of the second element of the reinforcing rim is attached by heat welding to a portion of the first face of the support layer of the first element of the reinforcing rim. Furthermore, the remaining portion of the second face of the support layer of the second element is attached by heat welding to a portion of the membrane, and the remaining portion of the first face of the support layer of the first element is attached by heat welding to a portion of the membrane.

[0114] In another embodiment of the application, the entire second face of the support layer of the second element of the reinforcing rim is attached by heat welding to the membrane, and a portion of the first face of the support layer of the first element of the reinforcing rim is attached by heat welding to the membrane. The remaining portion of the first face of the support layer of the first element of the reinforcing rim will be intended to be attached around the periphery of the pressure equalization opening of the device provided with a pressure equalization opening.

[0115] Furthermore, in these two embodiments just described above, the entire first face of the support layer of the second element of the reinforcing rim can be attached by heat welding around the periphery of the pressure equalization opening of the device, and, where appropriate, the remaining portion of the first face of the support layer of the first element of the reinforcing rim can be attached by heat welding around the periphery of the pressure equalization opening of the device.

[0116] In these embodiments of the application, the heat welding can be performed by a method such as ultrasonic or laser welding.

[0117] The method of manufacturing the pressure equalization membrane according to the application is entirely within the capabilities of a person skilled in the art.

[0118] The present invention also relates to a device comprising a surface comprising a pressure equalization opening, said opening being covered by a pressure equalization membrane according to the present invention as described above.

[0119] The device can be selected from earthmoving equipment, road construction equipment, cranes, forklifts, tractors, charging stations, wind turbines, solar panels, containers, boats, car headlights or sealed housings for spotlights used outside.

[0120] In an embodiment of the present invention, wherein the membrane is double-layered and comprises a microporous film layer of a first polymeric material as described above and a second fabric material layer as described above, which is attached to said microporous film layer of a first polymeric material, preferably, and contrary to what is customary and known in the prior art, the microporous film layer of a first polymeric material is preferably opposite to the confined space of the device (in other words, the second fabric material layer is in contact with the external environment). This has the advantage of protecting the microporous film layer of a first polymeric material from external aggressions (e.g. gravel, insects) that could damage it and / or tear the film.

[0121] The present invention also relates to a method for protecting a pressure equalization opening into a confined space of a device according to the present invention as described above, characterized in that a pressure equalization membrane according to the present invention as described above is attached around the entire perimeter of said opening. BRIEF DESCRIPTION OF DRAWINGS

[0122] The present invention will be better understood by means of the detailed description given below, with reference to the attached drawings, which represent, by way of non-limiting example, embodiments of the equalization membrane according to the present invention.

[0123] Figure 1 is a perspective exploded view of a pressure equalization membrane according to the present invention.

[0124] Figure 2 is a top view of said pressure equalization membrane according to the present invention.

[0125] Figure 3 is a sectional view of said pressure equalization membrane according to the present invention along the axis III-III of Figure 2 . DETAILED DESCRIPTION

[0126] Figures 1 to 3 is shown a pressure equalization membrane 11 according to the present invention, comprising:

[0127] - the membrane 1 sold by the company PARKER under the trade name "QBV657D". This is a double-layered membrane comprising a film of PTFE polymeric material having a thickness of 15 pm, to which a layer of polyamide fabric material having a thickness of 100 pm is glued;

[0128] - a reinforcing edge 4.

[0129] The film 1 has a rectangular shape, with a length of 35 mm and a width of 15.5 mm.

[0130] The reinforcing edge 4 comprises a first element 5 and a second element 6, configured to clamp the film 1 around its entire perimeter.

[0131] The second element 6 of the reinforcing edge 4 is intended to be attached to a device (not shown in the figures) so that the pressure equalization film 11 covers a pressure equalization opening (not shown in the figures). The first element 5 of the reinforcing edge 4 is intended to be in contact with the environment outside the device.

[0132] The first and second elements (5, 6) of the reinforcing edge 4 each have the shape of a frame, the opening of which has a similar shape to the perimeter of the film 1.

[0133] More particularly, the first element 5 has the shape of a rectangular frame, with the following dimensions:

[0134] - an outer dimension of the frame of 40 mm in length and 19.5 mm in width;

[0135] - an inner dimension of the frame of 32 mm in length and 11.5 mm in width;

[0136] The second element 6 has the shape of a rectangular frame, with the following dimensions:

[0137] - an outer dimension of the frame of 40 mm in length and 19.5 mm in width;

[0138] - an inner dimension of the frame of 30 mm in length and 9.5 mm in width;

[0139] In view of these aspects, the following covering dimensions exist:

[0140] - 2 mm in width and 1.5 mm in length between the first element 5 and the film 1;

[0141] - 3 mm in width and 2.5 mm in length between the second element 6 and the film 1.

[0142] The first element 5 comprises a PET support layer 2 with a thickness of 50 pm.

[0143] The support layer 2 of the first element 5 has:

[0144] - a first face 7 covered with a first acrylic adhesive layer 12 with a thickness of 90 pm;

[0145] - a second face 8.

[0146] The second element 6 comprises a support layer 3 of PET with a thickness of 50 pm.

[0147] The support layer 3 of the second element 6 has:

[0148] - a first face 9 covered with a second acrylic adhesive layer 13 with a thickness of 60 pm;

[0149] - a second face 10 covered with a third acrylic adhesive layer 14 with a thickness of 60 pm.

[0150] More precisely, the second element 6 is made of a double-sided adhesive material sold by the company GERGONNE SAS under the trade name “GERGOTAP E 296X”.

[0151] Figures 1 to 3 The pressure equalizing membrane 11 shown corresponds to the membrane IQ1 used in the following experiments.

[0152] Experimental section

[0153] Experiments were carried out on pressure equalizing membranes according to the application and on comparative membranes in order to demonstrate the advantages and benefits provided by the pressure equalizing membranes according to the application.

[0154] The 7 pressure equalizing membranes according to the application (IQ1 to IQ7) have the following characteristics.

[0155] The first membrane IQ1 according to the application corresponds to the membrane shown in Figures 1 to 3 and described above.

[0156] The second pressure equalizing membrane IQ2 according to the application differs from the membrane IQ1 only in that this membrane is a membrane sold by the company BERGHOF under the trade name “M100WL”. It is a double-layer membrane with a total thickness of 140 pm comprising a PTFE layer on which a layer of non-woven fabric material made of PET is glued.

[0157] The third pressure equalizing membrane IQ3 according to the application differs from the membrane IQ1 only in that this membrane is a membrane sold by the company DONALDSON under the trade name “EN0711066”. It is a double-layer membrane with a total thickness of 170 pm comprising a PTFE layer on which a layer of non-woven fabric material made of PET is glued.

[0158] The fourth pressure equalizing membrane IQ4 according to the application differs from the membrane IQ1 only in that this membrane is a membrane sold by the company DONALDSON under the trade name “EN0701435”. It is a double-layer membrane comprising a PTFE layer with a thickness of 50 pm on which a layer of polyamide non-woven fabric material with a thickness of 200 pm is glued.

[0159] ​Therefore, the pressure equalizing membranes IQ1 to IQ4 all have a double-layer membrane and are identical in size in terms of the membrane and the reinforcing edge.

[0160] The fifth pressure equalizing membrane IQ5 according to the present application differs from the membrane IQ1 in that:

[0161] - the membrane is a single-layer membrane sold by the company MICROVENT under the trade name "MV72040". It is a single-layer PTFE membrane with a thickness of 200 pm;

[0162] - the second element of the reinforcing edge is a double-sided adhesive material sold by the company TESA under the trade name "TESA4965".

[0163] More particularly, said second element comprises a PET support layer with a thickness of 12 pm and has:

[0164] - a first face covered with a layer of acrylic adhesive with a thickness of 97 pm;

[0165] - a second face covered with a layer of acrylic adhesive with a thickness of 97 pm.

[0166] The dimensions of the fifth pressure equalizing membrane IQ5 according to the present application are as follows:

[0167] - the membrane has a rectangular shape with a length of 40 mm and a width of 19.5 mm,

[0168] - the first element of the reinforcing edge has the shape of a rectangular frame with outer dimensions of 48 mm in length and 27.5 mm in width and inner dimensions of 32 mm in length and 11.5 mm in width;

[0169] - the second element of the reinforcing edge has the shape of a rectangular frame with outer dimensions of 40 mm in length and 19.5 mm in width and inner dimensions of 30 mm in length and 9.5 mm in width.

[0170] In view of these aspects, the following covering dimensions exist:

[0171] - 4 mm in the width direction and 4 mm in the length direction between the first element of the reinforcing edge and the membrane;

[0172] - 5 mm in the width direction and 5 mm in the length direction between the second element of the reinforcing edge and the membrane.

[0173] The sixth pressure equalizing membrane IQ6 according to the present application differs from the membrane IQ5 in that:

[0174] - the membrane is a single-layer PTFE membrane with a thickness of 150 pm;

[0175] - the second element of the reinforcing edge is a double-sided adhesive material,

[0176] The assembly consisting of the film and the second element is sold by the company GORE under the trade name "AVS 9".

[0177] More precisely, the second element has a total thickness of 140 pm and comprises a support layer having:

[0178] - a first face covered with a layer of silicone adhesive;

[0179] - a second face covered with a layer of silicone adhesive.

[0180] The seventh pressure equalizing film IQ7 according to the application differs from the film IQ5 in that:

[0181] - the film is a film sold by the company BERGHOF under the trade name "M40W". It is a single-layer PTFE film with a thickness of 300 pm;

[0182] - the second element reinforcing the edge is made of the same double-sided adhesive material as the films IQ1 to IQ4 (i.e. the double-sided adhesive material sold by the company GERGONNE SAS under the trade name "GERGOTAPE 296X").

[0183] Thus, the pressure equalizing films IQ5 to IQ7 all have a single-layer film and the same dimensions in terms of film and reinforcing edge.

[0184] The 11 comparative pressure equalizing films (C1 to C11) have the following characteristics.

[0185] The first comparative pressure equalizing film C1 differs from the first pressure equalizing film IQ1 according to the application in that it does not have a reinforcing edge. It only comprises a film identical to that of the pressure equalizing film IQ1 but with different dimensions (i.e. a length of 40 mm and a width of 19.5 mm) and means for attaching to the device. This attachment means is identical to the second element of the reinforcing edge of the pressure equalizing film IQ1 according to the application. Thus, it has the shape of a rectangular frame whose outer dimensions correspond to those of the film and is attached around the entire periphery of said film.

[0186] The second comparative pressure equalizing film C2 differs from the second pressure equalizing film IQ2 according to the application in that it does not have a reinforcing edge. It only comprises a film identical to that of the pressure equalizing film IQ2 but with different dimensions (i.e. a length of 40 mm and a width of 19.5 mm) and means for attaching to the device. This attachment means is identical to the second element of the reinforcing edge of the pressure equalizing film IQ2 according to the application. Thus, it has the shape of a rectangular frame whose outer dimensions correspond to those of the film and is attached around the entire periphery of said film.

[0187] The third comparative pressure equalizing membrane C3 differs from the third pressure equalizing membrane IQ3 according to the application in that it does not have a reinforcing edge. It comprises only the same membrane as the pressure equalizing membrane IQ3 but with different dimensions, namely a length of 40 mm and a width of 19.5 mm, and means for attachment to a device. The attachment means are identical to the second element of the reinforcing edge of the pressure equalizing membrane IQ3 according to the application. It thus has the shape of a rectangular frame whose outer dimensions correspond to the dimensions of the membrane and is attached around the entire periphery of said membrane.

[0188] The fourth comparative pressure equalizing membrane C4 differs from the fourth pressure equalizing membrane IQ4 according to the application in that it does not have a reinforcing edge but only comprises the same membrane as the pressure equalizing membrane IQ4 but with different dimensions, namely a length of 40 mm and a width of 19.5 mm, and means for attachment to a device. The attachment means are identical to the second element of the reinforcing edge of the pressure equalizing membrane IQ4 according to the application. It thus has the shape of a rectangular frame whose outer dimensions correspond to the dimensions of the membrane and is attached around the entire periphery of said membrane.

[0189] The fifth comparative pressure equalizing membrane C5 differs from the fifth pressure equalizing membrane IQ5 according to the application in that it does not have a reinforcing edge but only comprises the same membrane as the pressure equalizing membrane IQ5 and means for attachment to a device. The attachment means are identical to the second element of the reinforcing edge of the pressure equalizing membrane IQ5 according to the application. It thus has the shape of a rectangular frame whose outer dimensions correspond to the dimensions of the membrane and is attached around the entire periphery of said membrane.

[0190] The sixth comparative pressure equalizing membrane C6 differs from the sixth pressure equalizing membrane IQ6 according to the application in that it does not have a reinforcing edge but only comprises the same membrane as the pressure equalizing membrane IQ6 and means for attachment to a device. The attachment means are identical to the second element of the reinforcing edge of the pressure equalizing membrane IQ6 according to the application. It thus has the shape of a rectangular frame whose outer dimensions correspond to the dimensions of the membrane and is attached around the entire periphery of said membrane.

[0191] The seventh comparative pressure equalizing membrane C7 differs from the seventh pressure equalizing membrane IQ7 according to the application in that it does not have a reinforcing edge. It comprises only the same membrane as the pressure equalizing membrane IQ7 and means for attachment to a device. The attachment means are identical to the second element of the reinforcing edge of the pressure equalizing membrane IQ7 according to the application. It thus has the shape of a rectangular frame whose outer dimensions correspond to the dimensions of the membrane and is attached around the entire periphery of said membrane.

[0192] The eighth comparative pressure equalizing membrane C8 differs from the first pressure equalizing membrane IQ1 according to the application in that:

[0193] - the dimensions of the membrane are different (i.e. 40 mm long, 19.5 mm wide);

[0194] - the internal dimensions of the frame of the second element are different (i.e. 32 mm long, 11.5 mm wide).

[0195] The ninth comparative pressure equalizing membrane C9 differs from the second pressure equalizing membrane IQ2 according to the application in that:

[0196] - the dimensions of the membrane are different (i.e. 40 mm long, 19.5 mm wide);

[0197] - the internal dimensions of the frame of the second element are different (i.e. 32 mm long, 11.5 mm wide).

[0198] The tenth comparative pressure equalizing membrane C10 differs from the third pressure equalizing membrane IQ3 according to the application in that:

[0199] - the dimensions of the membrane are different (i.e. 40 mm long, 19.5 mm wide);

[0200] - the internal dimensions of the frame of the second element are different (i.e. 32 mm long, 11.5 mm wide).

[0201] The eleventh comparative pressure equalizing membrane C11 differs from the fifth pressure equalizing membrane IQ5 according to the application in that the first element of the reinforced edge has the shape of a rectangular frame with external dimensions of the frame of 40 mm long, 19.5 mm wide and internal dimensions of the frame of 30 mm long, 9.5 mm wide.

[0202] Thus, the equalizing membranes IQ1 to IQ4 according to the application all comprise a membrane with a surface of 542.5 mm 2 , while the comparative equalizing membranes C1 to C4 all comprise a membrane with a surface of 780 mm 2 . These equalizing membranes IQ1 to IQ4 according to the application have the advantage of containing less PTFE than the corresponding comparative equalizing membranes C1 to C4.

[0203] The comparative pressure equalizing membranes C8 to C11 are pressure equalizing membranes in which the first element and the second element sandwich the membrane flush around the entire perimeter of the membrane. Thus, the pressure equalizing membranes C8 to C11 have a configuration similar to the venting device described in the above- cited US patent 9,875,733 B2.

[0204] Test No. 1 with double layer films IQ1 to IQ4, C1 to C4 and C8 to C10

[0205] The pressure equalizing membranes IQ1 to IQ4, C1 to C4 and C8 to C10 are from the same manufacturer The water jet of the high-pressure cleaner was pressurized to evaluate the improvement of the membrane according to the application compared to the comparative membranes in terms of resistance to delamination.

[0206] The pressurized water jet simulates the severe conditions that a pressure equalizing membrane can be subjected to, i.e. for example bad weather.

[0207] The pressure equalizing membrane under test was applied to a solid aluminum raw material plate of 400 mm in length 24 hours before the test. The plate was positioned at an angle of 150° to the water jet of the high-pressure cleaner, the water jet of the high-pressure cleaner was set to a pressure of 210 bar and the distance between the nozzle of the cleaner and the plate was set to 50 cm. The water jet thus impacted the membrane under test.

[0208] The test was carried out for a maximum duration of 2 minutes. However, the test was stopped as soon as the entire pressure equalizing membrane under test was damaged. During the entire test, the water jet was moved from left to right in order to pressurize the membrane under test. The nozzle was moved at a speed of 5 back and forth movements per minute.

[0209] Test No. 2 with single layer films IQ5 to IQ7, C5 to C7 and C11

[0210] The procedure of the second test was identical to that of the first test, except that the severity of the test was increased.

[0211] In fact, the aluminum plate was positioned at an angle of 150° to the water jet of the high-pressure cleaner, the water jet of the high-pressure cleaner was set to a pressure of 210 bar and the distance between the nozzle of the cleaner and the plate was set to 35 cm (no longer 50 cm). The water jet thus impacted the membrane under test.

[0212] The test was carried out for a maximum duration of 2 minutes. However, the test was stopped as soon as the entire pressure equalizing membrane under test was damaged. During the entire test, the water jet was moved from left to right in order to pressurize the membrane under test. The nozzle was moved at a speed of 5 back and forth movements per minute.

[0213] Table 1 below details the results obtained for all the pressure equalizing membranes tested. More specifically, for each membrane under test, the resistance time to the pressurized water is shown as well as its condition after the test was stopped.

[0214] For the pressure equalizing membranes comprising a double-layer membrane, the second column of Table 1 indicates:

[0215] - when the microporous membrane layer of the polymeric material of the membrane, i.e. PTFE, is exposed to the high-pressure water jet, this column is “polymer”;

[0216] - when the layer of textile material of the membrane, i.e. polyamide or PET, is exposed to the high-pressure water jet, this column is “textile”.

[0217] Therefore, two possible configurations were tested for the films IQ1, IQ2, C1 and C2.

[0218] In the last column of Table 1, the following terms are understood:

[0219] - "[...] % of the surface on which cohesive failure of the adhesive" means that at the end of the test, the pressure equalizing film under test detached from the aluminum plate on [...]% of the surface and parts of the adhesive were found on the aluminum plate;

[0220] - "[...] % of the surface on which adhesive failure between the film and the adhesive" means that at the end of the test, the pressure equalizing film under test detached from the aluminum plate on [...]% of the surface and all the adhesive remained on the second element of the reinforced edge.

[0221]

[0222] Table 1 details the results of the resistance time test for all the pressure equalizing films and the condition of the films after the test was stopped

[0223] In view of the results detailed in Table 1 above, the following notable points are noted:

[0224] - unlike the pressure equalizing films C1 to C4, the pressure equalizing films IQ1 to IQ4 according to the invention all remained intact after 2 minutes of test No. 1. They were not damaged when subjected to a pressurized water jet.

[0225] - as regards the pressure equalizing film IQ1, this pressure equalizing film remained intact in the configuration in which the fabric material was exposed to the pressurized water jet. In fact, in the configuration in which the PTFE film was exposed to the pressurized water jet, this PTFE layer was torn on 40% of the surface of the film. This experiment shows that it can be more advantageous to expose the fabric material layer to the outside environment for the equalizing film according to the invention.

[0226] - as regards the pressure equalizing film IQ2, this pressure equalizing film remained intact whatever its configuration, i.e. whether the fabric material (PET) or the microporous film of polymer material (PTFE) of the film was exposed to the pressurized water jet.

[0227] - test No. 2 is more aggressive (reduction of the nozzle-aluminum plate distance). However, the pressure equalizing films IQ5 to IQ7 according to the invention all resisted the pressurized water jet better than the comparative films C5 to C7. The film IQ5 remained intact at the end of the test.

[0228] - comparing the results of films IQ6 and C6, the film IQ6 has a longer protection time (120 s against 80 s) and is less damaged at the end of test No. 2 (cohesive failure of the adhesive occurs on 50% of the surface, whereas it occurs on 100% of the surface for the film C6).

[0229] - The comparative pressure balanced membranes C8 to C10 all deteriorate when subjected to a pressurized water jet.

[0230] - The comparative pressure balanced membrane C11 cannot withstand a pressurized water jet.

[0231] These experimental results show that the pressure balanced membranes according to the present application have better robustness and reliability compared to comparative pressure balanced membranes that do not have a reinforced edge, or in which the first and second elements of the reinforced edge are flush with the membrane, as is the case for the vent described in US patent 9,875,733 B2.

[0232] Furthermore, as mentioned above, some of the pressure balanced membranes according to the present application, namely IQ1 to IQ4, have the advantage of comprising less PTFE than the corresponding comparative pressure balanced membranes, namely C1 to C4. They are thus less impactful on the environment and more economical.

Claims

1. A pressure equalizing membrane (11) comprising a membrane (1) and a reinforcing edge (4), a part or all of the perimeter of the membrane (1) being clamped by the reinforcing edge (4) comprising a first element (5) and a second element (6), each of the first element (5) and the second element (6) comprising a support layer (2, 3), the support layer (2) of the first element (5) having a first face (7) and a second face (8), the support layer (3) of the second element (6) having a first face (9) and a second face (10), characterized in that: - a part of the second face (10) of the support layer (3) of the second element (6) is attached to a part of the first face (7) of the support layer (2) of the first element (5), the remaining part of the second face (10) of the support layer (3) of the second element (6) being attached to a part of the membrane (11), and the remaining part of the first face (7) of the support layer (2) of the first element (5) being attached to a part of the membrane (11) or - the entire second face (10) of the support layer (3) of the second element (6) is attached to the membrane (11), and a part of the first face (7) of the support layer (2) of the first element (5) is attached to the membrane (11).

2. Pressure equalizing membrane (11) according to claim 1, characterized in that the membrane (1) is a monolayer microporous film of a polymeric material selected from the group consisting of polytetrafluoroethylene (hereinafter "PTFE"), polychlorotrifluoroethylene (hereinafter "PCTFE"), polyvinyl fluoride (hereinafter "PVF"), polysiloxane, polycarbonate (hereinafter "PC") and polyester.

3. Pressure equalizing membrane (11) according to claim 1, characterized in that the membrane (1) is a bilayer and comprises a microporous film layer of a first polymeric material selected from the group consisting of PTFE, PCTFE, PVF, polysiloxane, PC and polyester, and a second fabric material layer attached to the microporous film layer of the first polymeric material, the fabric material being selected from fabrics based on polyethylene terephthalate (hereinafter "PET"), polyamide, polypropylene, polyethylene, acrylic, PTFE, elastane, glass fiber, carbon or cellulose.

4. Pressure equalizing membrane (11) according to any one of claims 1 to 3, characterized in that the first element and the second element (5, 6) of the reinforcing edge (4) each have a frame shape, the opening of the frame having a similar shape to the perimeter of the membrane (1).

5. Pressure equalizing membrane (11) according to any one of claims 1 to 4, characterized in that the material of the support layers (2, 3) of the first element (5) and of the second element (6) is selected from the group consisting of PET, polyethylene naphthalate (abbreviated as "PEN"), polyvinyl chloride (abbreviated as "PVC"), polyamide, polypropylene and metal foil, the material of the support layer (2) of the first element (5) being the same as or different from the material of the support layer (3) of the second element (6).

6. The pressure equalizing membrane (11) according to any one of claims 1 to 5, characterized in that: - the first face (7) of the support layer (2) of the first element (5) is covered with an adhesive (12), - the second face (10) of the support layer (3) of the second element (6) is covered with an adhesive (14).

7. Pressure equalizing membrane (11) according to claim 6, characterized in that The first face (9) of the support layer (3) of the second element (6) is covered with an adhesive (13).

8. Pressure equalizing membrane (11) according to any one of claims 6 and 7, characterized in that The adhesive (12, 13, 14) is selected from pressure sensitive adhesives, preferably adhesives based on acrylic resin, silicone, rubber or polyurethane.

9. A device comprising a surface, which surface comprises a pressure equalization opening, which pressure equalization opening is covered by a pressure equalization membrane (11) according to any one of claims 1 to 8.

10. The apparatus of claim 9, wherein, The device is a sealed enclosure selected from earthmoving equipment, road building equipment, cranes, forklifts, tractors, charging stations, wind turbines, solar panels, containers, ships, car headlights or spotlights for external use.

11. A method for protecting a pressure equalization opening, which pressure equalization opening opens into a restricted space of a device according to claim 9 or 10, characterized in that, The pressure equalization membrane (11) according to any one of claims 1 to 8 is attached around the entire periphery of the opening. The pressure equalization membrane (11) according to any one of claims 1 to 8 is attached around the entire periphery of the opening.

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