JP2008528286A - Breather filter to reduce pollutant diffusion - Google Patents

Abstract

  The present invention relates to a breather filter (400) that can reduce or prevent the transmission of contaminants due to diffusion. In an embodiment, the present invention includes a breather filter (400) assembly that includes a valve. The valve includes a first layer (420) defining a first opening (403), a second layer (422) defining a second opening (402), and a third layer disposed between the first layer and the second layer. And the third layer includes a filter medium. The first layer (420) is configured to bend away from the second layer (422) that forms an air gap between the first layer and the third layer. In an embodiment, the present invention includes a first layer (420), a second layer (422), a filter element (408) disposed between the first layer and the second layer, a first side and a second side. And a breather filter (400) including a valve assembly including a side. The valve assembly can be configured to change from a closed configuration to an open configuration when the air pressure difference between the first side and the second side exceeds a threshold.

Description

  The present invention relates to a filter for an electronic device container. In particular, the present invention relates to a breather filter that can reduce or prevent entry of contaminants due to diffusion.

  This application is in the name of Donaldson Company Inc., a U.S. company that is the applicant for all designated countries other than the U.S. Was filed as a PCT international patent application on February 3, 2006 in the name of US citizen Amy Butterfield, Japanese citizen Katsushi Isogawa and US citizen Carl Soldner, 2005 Claims priority to US Provisional Patent Application No. 60 / 649,711, filed February 3, 2000.

  Hard disk drives and other electronic devices are often placed in containers to provide the clean environment necessary for optimal operation of the device. However, contaminants can still enter the electronics container from external sources and can be generated from the container during use. Contaminants including particulates, gases and liquids such as water vapor, can gradually damage the drive and cause performance degradation, and in some situations can even cause complete drive failure suddenly.

  When a disk drive or other electronic device is in operation, the air in the container is often heated to increase the pressure of the air in the container. As a result of the increased air pressure, air leaks from the container if the container has a breather hole or is not sealed and airtight. Conversely, when the disk drive or other electronic device stops operating, the air in the container cools and the pressure of the air in the container decreases. As a result of the reduced air pressure, air moves into the drive if the container is not airtight with a breather hole or sealed. If contaminants are present in the air and move into the container, the interior of the container will be contaminated.

  Breather filters are often used to prevent contaminants carried by the exchanged air from entering the electronics enclosure. The breather filter can be placed above the breather hole to remove contaminants from the air entering the container. Many breather filter designs include a fluid communication channel between the interior of the electronics enclosure and the outside environment, but that channel is always open to the air channel. . Therefore, the air moves through the breather filter in order to equalize the pressure difference of the air generated between the inside and outside of the electronic device container. However, because the fluid communication channel is always open, contaminants can move through the channel by a diffusion process even when there is no air ingress or exhaust.

  Accordingly, there is a need for a breather filter that can reduce or prevent contaminant ingress by diffusion.

SUMMARY OF THE DISCLOSURE The present invention relates to a breather filter that can reduce or prevent entry of contaminants into an electronic device container. In an embodiment, the present invention includes a breather filter assembly that includes a valve. The valve includes a first layer defining a first opening, a second layer defining a second opening, and a third layer including a filter medium disposed between the first layer and the second layer. The third layer is attached to at least one of the first layer and the second layer. The first layer is configured to bend away from the second layer that creates an air gap between the first layer and the third layer.

  In one embodiment, the present invention includes an electronic including a first layer, a second layer, a filter element disposed between the first layer and the second layer, and a valve assembly including the first side and the second side. Includes a breather filter for the equipment container. The valve assembly has an open configuration and a closed configuration. The valve assembly is configured to change from the closed configuration to the open configuration when an air pressure difference between the first side and the second side exceeds a threshold value.

  In one embodiment, the present invention includes a valve assembly for a breather filter that includes a first layer defining a plurality of pores and a second layer defining a plurality of pores. The valve assembly can be configured to assume a closed position and an open position, wherein the first layer and the second layer are adjacent to each other in the closed position with non-linearly aligned pores. In the open position, the air gap separates the position of the first layer from the position of the second layer.

  In one embodiment, the present invention includes a breather filter assembly that includes a substrate layer, a valve layer, and a filter media layer. The filter media layer can be disposed between the substrate layer and the valve layer. The valve layer can include a first layer defining a plurality of inner pores and a second layer defining an outer flap. The first layer can be adjacent to the second layer and the outer flap can be configured to bend away from the inner pore.

  The above summary of the present invention is not intended to describe each discussed embodiment of the present invention. This is the purpose of the figures and the detailed description below.

  While the invention is susceptible to various modifications and alternative forms, specifics thereof have been shown and described in detail through examples and drawings. However, it should be understood that the invention is not limited to the specific embodiments described. On the contrary, the invention can include modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

  The term “valve” as used herein refers to initiating, stopping, or at least, a fluid flow by a moving part that opens, stops, or plugs one or more fluid flow ports or channels. It relates to the device to be relieved.

  As used herein, the term “active valve” refers to the valve itself being operated by external means such as mechanical, hydraulic, pneumatic, electrical or electromagnetic actuation. Regarding the valve.

  The term “passive valve” as used herein relates to a valve whose opening and closing is directly actuated by the pressure in the fluid flow that controls the valve.

  The terms “adsorbent” and “absorbent” as used herein relate both to an absorbent or an adsorbent material, unless the specific context refers to the opposite. That is, no mention is made of the special nature of the interaction between the collected contaminants and the filter material.

  Embodiments of the present invention include a breather filter that can reduce or prevent contaminant ingress due to diffusion. Some embodiments of the present invention include a valve that opens to equalize air pressure when a threshold air pressure difference exists, but when the valve does not exist a threshold air pressure difference Close to prevent or reduce the entry of contaminants into the breather filter and / or the electronics container by diffusion.

  FIG. 1 is a perspective view of a filter 100 according to an embodiment of the present invention. The filter 100 has an upper layer 104 and an air valve assembly 102. In some embodiments, the top layer 104 is made of a material that is substantially impermeable to fluid, such as a barrier membrane. The air valve assembly 102 opens when the pressure difference between the two sides of the valve reaches a threshold value. The air valve assembly 102 is controlled so that the threshold is set to the desired pressure differential.

  FIG. 2 is a plan view of the filter of FIG. The air valve assembly 102 is disposed in the center of the upper layer 104. However, it will be appreciated that the air valve assembly 102 may be offset from the center of the top layer 104. FIG. 3 is a cross-sectional view of the filter 100 of FIG. 1 attached to the electronics container 112 and taken along line A-A ′ of FIG. 2. It will be appreciated that the filter 100 can be attached to the electronics container 112 using conventional techniques including the use of adhesives or mechanical fasteners. The air valve assembly 102 is aligned with the breather port 110 in the electronics container 112. The upper layer 104 of the filter is adjacent to the inner surface 114 of the electronics container 112. Thus, in the illustrated embodiment, the filter is mounted inside the electronics container 112. However, it will be appreciated that in an alternative embodiment, a filter can also be attached outside the electronics container 112. The peripheral edge of the upper layer 104 is attached to the peripheral edge of the lower layer 106.

  In some embodiments, the air valve assembly 102 opens only when the air pressure on the upper side 116 of the air valve assembly 102 is a threshold amount greater than the air pressure on the lower side 118 of the air valve assembly 102. In other embodiments, it opens only when the air pressure on the upper side 116 of the air valve assembly 102 is a threshold amount less than the air pressure on the lower side 118 of the air valve assembly 102. In yet another embodiment, the valve assembly 102 opens when the air pressure on the upper side 116 of the air valve assembly 102 is greater or less than a threshold amount of air pressure on the lower side 118 of the air valve assembly 102.

  The lower layer 106 can be a fluid permeable membrane. In one embodiment, the lower layer 106 is an expanded polytetrafluoroethylene membrane PTFE. However, in some embodiments, the lower layer 106 is made of a material that is substantially impermeable to fluid and has one or more openings (not shown). The filter element 108 is disposed between the upper layer 104 and the lower layer 106. The filter element 108 can include various filter media (including activated carbon) depending on the type of contaminant removed by the breather filter. Various types of filter media are described in further detail below. Filter element 108 can be included in the scrim as desired. In some embodiments, the filter element 108 can absorb water vapor.

  Electronic device containers such as disk drive housings are used inside increasingly smaller electronic components. Therefore, it is advantageous that the breather filter is not larger than necessary. In some embodiments, the total thickness of the breather filter is less than about 5 mm. In certain embodiments, the total thickness of the breather filter is less than about 3 mm, optionally less than 2 mm, and in some embodiments less than 1 mm.

  The filter shown in FIG. 3 can be functionalized to allow air to pass as needed to prevent large pressure differences formed between the interior and exterior of the electronics enclosure. . For example, when the pressure of air on the lower side 118 of the air valve assembly 102 is greater than the upper side 116 of the air valve assembly, the air passes through the lower layer 106, and the filter element 108, the air valve assembly 102, and then It is possible to go out of the breather port 110 in the container 112 of the electronic device. Thus, when air flows out, the pressure differential across the air valve assembly 102 is reduced and the air valve assembly 102 closes when the pressure differential falls below a threshold. Conversely, when the pressure of air on the upper side 116 of the air valve assembly 102 is greater than on the lower portion 118 of the air valve assembly, the air passes through the breather port 110 and the air valve assembly 102, filter element 108, lower layer 106, electrons Enters the device receptacle and equalizes the air across the valve assembly 102.

  The filter illustrated in FIG. 3 can reduce the amount of contaminants diffusing from the outside into the electronics container as compared to a breather filter that includes a fluid channel that is always open. One reason for this is that since the air valve assembly 102 is closed and the air valve assembly 102 physically obstructs the flow path, the amount of contaminants that can enter the interior of the electronics container is relatively low. Because. Further, the filter element 108 can act to adsorb any contaminants that diffuse through the air valve assembly 102 even when in the closed state.

  It will be appreciated that the air valve assembly 102 may take a variety of forms. The air valve assembly 102 can be either an active valve or a passive valve. In general, passive air valves can be manufactured at a lower cost than active valves. In an embodiment, the filter of the present invention includes a passive air valve. Many different kinds of passive air valves can be used. FIG. 4 shows one embodiment of a sectional view of the passive valve 200. Passive valve 200 includes a first layer 202 and a second layer 206. The first layer 202 has a plurality of pores 204 that are sufficiently large in diameter to allow air flow. Similarly, the second layer 206 has a plurality of pores 208 that are sufficiently large in diameter to allow air flow. In an embodiment, the pores 204 in the first layer 202 and the pores 208 in the second layer 206 are at least about 0.5 mm in diameter.

  The passive valve 200 has a closed configuration illustrated in FIG. 4 and an open configuration illustrated in FIG. In the closed configuration shown in FIG. 4, the first layer 202 and the second layer 206 are positioned relative to each other in such a way that the first layer of pores 204 do not line up with the second layer of pores 208. Therefore, the air flow across the first layer 202 and the second layer 206 is shielded when the passive valve 200 is in a closed configuration. In some embodiments, the valve 200 includes a liquid composition (not shown) between the first layer 202 and the second layer 206. The liquid composition enhances the filter's ability to shield the air flow across the passive valve 200 when the passive valve 200 is in the closed position. The liquid composition can also help control the amount of force required to move the passive valve 200 from the closed position to the open position.

  The first layer 202 of the passive valve 200 can be made from a material that deforms (or bends) when a force is applied. When the air pressure is greater at the second side 212 than at the first side 214 of the valve, the passive valve can assume the open position. In particular, when the air pressure is greater on the second side 212 than the first side 214 of the valve, the first layer 202 bends away from the second layer 206, and the second layer pore 208 and the first layer pore 204 An air flow path is formed between them. In the open position, air can flow through the passive valve in the direction of arrow 210. The first layer 202 can be formed with a pore in the air flow path and is made of a material that is sufficiently flexible so that it can assume an open position when incorporated as part of a passive valve. be able to. For example, the passive valve first layer 202 can be made of a deformable polymer membrane. As a further example, the first layer can include polyurethane, polypropylene, polyester, or expanded polytetrafluoroethylene (PTFE). In some embodiments, the second layer 206 is less flexible than the first layer 202. This can be achieved in various ways. For example, the second layer 206 can be made thicker than the first layer 202. As a further example, the second layer 206 can be made of a material that is less flexible than the material used to make the first layer 202. Also, in certain embodiments, both the first layer 202 and the second layer 206 are sufficiently flexible, depending on the direction of the pressure difference between the first side 214 and the second side 212 of the container, Allow air flow in either direction (into or out of the container).

  FIG. 6 is a perspective view of a filter 300 according to an embodiment of the present invention. In this figure, the filter 300 is shown having an upper layer 304 that defines two upper ports 302. Depending on the configuration of the filter relative to the electronics container, the upper port 302 can provide fluid communication between the interior of the filter and the exterior of the electronics container, or the upper port 302 can be Fluid communication between the interior of the filter and the interior of the electronics container can be provided. It will be appreciated that in some embodiments, the filter includes only one upper port. However, the filter can also include more than one upper port 302. If the upper port is too small, the air flow is obstructed.

  FIG. 7 is a plan view of the filter 300 of FIG. 6 and includes the inside and the bottom of the filter 300. In this figure, the lower port 306 is illustrated by a dotted line. Depending on the filter configuration for the electronics container, the lower port is a fluid port between the filter interior and the electronics container external filter interior, or between the filter interior and the electronics container interior. Communication can be provided. Embodiments of the invention can include more than one lower port. If the lower port is too small, it is not preferable because the air flow is obstructed. FIG. 7 shows the filter element 308 inside the filter. The filter element 308 can be operated to remove contaminants from the air inside the filter. The filter element can be ring-shaped (or ring-shaped). However, the filter element can take other shapes. Filter element 308 can be included in the scrim as desired.

  The filter element 308 can include a filter medium that removes contaminants from the air flow through the breather filter 300. The filter element 308 can also remove contaminants that otherwise diffuse into the breather filter 300. In some embodiments, the filter element 308 can be made of a material that expands in the presence of water vapor. As an example, the filter element 308 may include activated carbon, silica gel, a polymer that absorbs water and expands, or a combination thereof. In one embodiment, the filter element 308 includes a superabsorbent polymer. As an example, the superabsorbent polymer may be Sumitomo Seika Chemical's Aquakeep SA60N Type II or NAFION from DuPont, Wilmington, Delaware.

  8 is a cross-sectional view of the filter 300 of FIG. 6 taken along line B-B ′ of FIG. The upper layer 304 is adjacent to the filter element 308. The filter element is attached to the lower layer 310. In the configuration illustrated in FIG. 8, the filter element 308 blocks the airflow path between the upper port 302 and the lower port 306. 9 is a cross-sectional view of the filter of FIG. 6 taken along line BB ′ of FIG. 7, showing the flow path through the filter when the pressure differential across the filter exceeds a threshold level. Yes. When the pressure of the air on the first side 314 of the filter is greater than the pressure of the air on the second side 316 of the filter, such as when rapidly heating the container, the upper layer 304 has a gap between the upper layer 304 and the filter element 308. Move to form. When this occurs, the airflow path is opened between the upper port 302 and the lower port 306 and the airflow, and the airflow is directed in the direction of the arrow 312. It will be appreciated that the filter element 308 may alternatively be attached to the upper layer 304 instead of the lower layer 310.

  As described above, whenever the filter element 308 is made of a material that expands in the presence of water or water vapor, the filter element 308 will pass through the filter 300 over time when exposed to much water vapor. It is possible to more effectively shield the air flow path. For example, referring again to the configuration illustrated in FIG. 8, the filter element 308 expands when exposed to water vapor so that the filter element 308 contacts the top layer 304 and the bottom layer 310 tightly, thereby providing a good seal. Will form and effectively shield the air flow. The expansion of expandable polymers that absorb water can also prevent diffusion of water vapor through the polymer itself due to a phenomenon known as gel-blocking.

  It will be appreciated that the filter of the present invention is attached to the electronics container above either the outer or inner breather hole of the electronics container. As an example, referring to FIG. 10, a filter of an embodiment of the present invention attached to an outer surface 322 of an electronic container 318 is illustrated. It will be appreciated that the filter may be attached to the electronics container 318 using general purpose techniques including the use of adhesives or mechanical fasteners. The electronic device container 318 has a breather hole 320. The filter is positioned so that the lower port 306 fits above the breather hole 320 of the electronics container. In contrast, FIG. 11 shows a cross-sectional view of a filter of an embodiment of the present invention attached to the interior surface 324 of an electronic container. In this embodiment, the spacer pad 326 provides an air gap between the surface 324 of the electronics container 318 and the upper port 302. The air gap formed by the spacer pad 326 is large enough that the upper layer 304 can bend sufficiently to form a flow path for airflow through the filter. FIG. 12 shows a perspective view from above of the filter of FIG. In this view, it can be seen that the spacer pads 326 are disposed on the upper layer 304 of the filter.

  Referring now to FIG. 13, there is illustrated a cross-sectional view of a filter 400 attached to the inner surface of an electronic container 430 according to another embodiment of the present invention. It will be appreciated that the filter 400 may be attached using conventional techniques including the use of adhesives or mechanical fasteners. FIG. 14 shows an enlarged view of a portion 432 of the filter of FIG. The filter has an upper layer 410 that defines an upper port 434. The filter has a valve layer 442 that includes a first layer 423 and a second layer 422. The first layer 423 includes a plurality of pores 402 (not shown in size) and a flap portion 420. The flap portion 420 is flexible and can move. Similarly, the second layer 422 includes a plurality of pores 403 (not shown in size) and a flap portion 418.

  When the valve layer 442 is in the closed position, the first layer 423 and the second layer 422 are arranged such that the flap portion 418 of the second layer 422 covers the pore 402 of the first layer 423. Similarly, in the closed position, the flap portion 420 of the first layer 423 covers the pore 403 of the second layer 422. Thus, in the closed position, air flow through the valve layer 442 is impeded.

  FIG. 15 shows how the filter 400 of FIG. 13 operates to allow air flow from one side of the electronic device container to the other surface of the electronic device container. When the pressure of the air on the inside 436 of the electronics container is greater than on the outside by a threshold, the first layer flap 420 will bend open, allowing air to flow through the filter in the direction of arrow 426. . FIG. 16 shows how the filter 400 of FIG. 13 operates to allow air flow from the outside of the electronic device container to the inside of the electronic device container. When the pressure of the air on the outer side 438 of the electronics container is greater than on the inner side 436, the second layer flap 418 is bent open, allowing the air to flow through the filter in the direction of arrow 428. . Thus, the filter of FIG. 13 will allow air to flow between the inner 436 and outer 438 of the electronics container 430 only when there is a sufficient pressure differential to cause one of the flaps 418, 420 to bend into the open position. Allows to flow forward and backward between.

  The amount of pressure difference required to cause the flaps 418, 420 to bend to the open position is based on factors such as the flexibility of the material used to make the flap, the thickness of the flap, the size of the flap, etc. Can be changed. However, it will be appreciated that the nature of the flap can be altered so that the pressure differential required to open the flap is as desired for the particular application. The first layer 423 and the second layer 422 of the valve layer 442 can be made of a polymer membrane that is substantially impermeable to fluid flow (in the absence of pores 402, 403). In some embodiments, the first layer 423 and the second layer 422 of the valve layer 442 include a shielding film.

  In some embodiments, the upper port 434 is positioned above the breather port in the electronics container 430 as illustrated in FIG. However, in other embodiments, the configuration is reversed as shown in FIG. 17, with the upper port 434 of the filter on the opposite side of the filter adjacent to the breather port 440 of the electronics container 430. It is in.

  Although not shown, it will also be appreciated that a valve layer having only a plurality of flaps on the first layer and a plurality of pores on the second layer can be made. This type of valve layer component would provide a one-way air flow path. Similarly, a valve layer having only a plurality of flaps on the second layer and a plurality of pores on the first layer can be made.

Filter Media In some embodiments of the present invention, the breather filter can contain the filter media in a filter element or filter layer. The filter media can include a particulate filtration media and / or an adsorbent filtration media. The particulate filter media used in the present invention can have efficiencies over a wide range of particle size sizes including from submicron to macroscopic size (preferably 0.02 μm or more). Suitable particulate filter media materials include, but are not limited to, microfiber glass media, high efficiency electo materials and membrane materials such as expanded polytetrafluoroethylene membrane, polypropylene membrane, polycarbonate and polyester. A film, a mixed ester film of cellulose, a polyvinyl chloride film, a cellulose triacetate film, a thin film composite film and / or a laminate thereof. A particularly suitable particulate filtration medium is expanded polytetrafluoroethylene (expanded PTFE or ePTFE) because of excellent filtration performance, suitability for covering the adsorbent layer and cleanliness. A preferred expanded PTFE membrane filters 0.1 μm diameter microparticles with a filtration efficiency of 99.99% with an air velocity of 10.5 ft / min, an airflow resistance of about 20 mm water column. The expanded PTFE copolymer is manufactured by W.W. L. It is commercially available as Gore-Tex (R) of Gore & Associates, Inc. Millipore PVDF can also be used in certain embodiments as a particulate filter media.

  The adsorbent media used in some embodiments of the present invention can be selected from a wide range of adsorbents prepared for a particular gas or gas of interest. These gases can cause oxidation or corrosion of, or affect the operation of, water vapor, dioctyl phthalate, silicone, chlorine, hydrogen sulfide, nitrogen dioxide, mineral acid gases, hydrocarbon compounds, and critical elements. Contains other gases that can condense on critical elements. The selected adsorbent medium can be one type of a combination of different medium types. The adsorbent medium may be a specially selected adsorbent targeted to a specific gas or may be an adsorbent with good adsorption performance for a wide range of gases.

  The adsorbent media used in the examples of the present invention are not limited to physical adsorbents such as silica gel, activated carbon, activated alumina, molecular sieves, desiccants such as clay, or without limitation, calcium carbonate, calcium sulfate. Chemical adsorbents such as potassium permanganate, sodium carbonate, potassium carbonate, sodium phosphate, powder materials or activated materials that react chemically to collect gas phase corrosive materials or contaminants, or others Of reactants.

  If a combination of adsorbents is used, they can be individual layers placed on top of each other or a single mixed layer. Alternatively, the adsorbent medium can be an adsorbent medium impregnated with one or more additional adsorbents, where the additional adsorbents include, but are not limited to, one or more chemical adsorbents as described above. For example, impregnated activated carbon, silica gel or alumina. A preferred broad range of adsorbent is activated carbon having a wide pore size distribution, impregnated with one or more chemical adsorbents such as calcium carbonate or sodium carbonate. A wide pore size distribution is used to provide a wide range of gases to be adsorbed, creating a broad base physical adsorbent. Carbonate is usually a good candidate for impregnation because the compounds released by chemical reaction with the chemical adsorbent are carbon dioxide, oxygen and water. The preferred adsorbent for a given contaminant depends on the contaminant, the pore size of the physical adsorbent selected to optimize performance for the particular contaminant, and the chemical composition of the chemical adsorbent.

  Adsorbent media include, but are not limited to, one or more of the following structures, such as 100% adsorbent material such as granular adsorbent, carbonized woven or non-woven material and latex, acrylic Nonwoven fabric impregnated with adsorbents such as cellulose or polymeric nonwoven fabrics or other binder systems, porous shaped adsorbents containing polymers or ceramics to maintain a porous structure, voids within the scaffold A polymer or polymer membrane impregnated with an adsorbent that functions as a porous scaffold with spaces filled with adsorbent. Polymeric scaffolds include, but are not limited to, expanded PTFE, polypropylene film, polyethylene film, polypropylene film, polyethylene film, polyvinylidene fluoride film, polyvinyl alcohol film, polyethylene terephthalate film, and films made of other polymers including. The adsorbent material may be a complete type or a mixture of numerous physical and / or chemical adsorbents.

  In some examples, the adsorbent medium can include a water-swellable component. In one embodiment, the adsorbent medium includes a water-absorbable polymer that is expandable with water. Water-swellable water-absorbing polymers are known as superabsorbent polymers. Water-swellable water-absorbing polymers include anionic polymers such as alkali metals and poly (acrylic acid) ammonium salts, poly (methacrylic acid), isobutylene / maleic anhydride copolymers, poly (vinyl acetate), poly ( Vinyl phosphonic acid), poly (vinyl sulfonic acid), carboxymethyl cellulose, carboxymethyl starch, carrageenan, alginic acid, polyaspartic acid, polyglutamic acid, combinations thereof, copolymers thereof, cationic polymers, poly (vinyl amines) ), Poly (ethylene imine), poly (amino propanol vinyl ether), poly (allyl amine), poly (quaternary ammonium), poly (diaryl dimethyl ammonium hydroxide), poly asparagine, polyglutamine , Polly Emissions, polyarginine, combinations thereof and copolymers thereof, may comprise a mixture of the above listed anionic polymer and cationic polymer. In one example, the water-swellable water-absorbing polymer comprises one of sodium polyacrylate, polyvinyl amine salt, polyacrylic acid, polyvinyl amine, and combinations and derivatives thereof. In one embodiment, the water-swellable water-absorbing polymer comprises AQUAKEEP SA60N available from Sumitomo Seika Chemicals. In another example, the water-swellable water-absorbing polymer can include NAFION available from DuPont, Wilmington, Delaware.

  Although the present invention has been described with reference to several specific implementations, those skilled in the art will recognize many modifications can be made without departing from the spirit and scope of the invention.

1 is a perspective view of a filter according to an embodiment of the present invention. It is a top view of the filter of FIG. FIG. 3 is a cross-sectional view of the filter of FIG. 1 taken along line A-A ′ of FIG. 2. 1 is a cross-sectional view of a closed passive valve according to an embodiment of the present invention. FIG. FIG. 5 is a cross-sectional view of the passive valve of FIG. 4 in an open state. 1 is a perspective view of a filter according to an embodiment of the present invention. It is a top view of the filter of FIG. FIG. 8 is a cross-sectional view of the filter of FIG. 6 taken along line BB of FIG. It is sectional drawing of the filter of FIG. 6 which shows the air which passes a filter. It is sectional drawing of the filter of one Example of this invention attached to the exterior of the container of an electronic device. It is sectional drawing of the filter of one Example of this invention attached inside the container of an electronic device. FIG. 12 is a perspective view of the filter shown in FIG. 11. FIG. 6 is a cross-sectional view of another filter according to an embodiment of the present invention. It is sectional drawing to which some filters of FIG. 13 were expanded. FIG. 14 is a partial cross-sectional view of the filter of FIG. 13 showing the air flow path through the filter. FIG. 14 is another cross-sectional view of a portion of the filter of FIG. 13 showing the air flow path through the filter. FIG. 6 is a cross-sectional view of another filter according to an embodiment of the present invention.

Claims (20)

A breather filter assembly including a valve,
The valve is
A first layer defining a first opening;
A second layer defining a second opening;
A third layer including a filter medium disposed between the first layer and the second layer;
The third layer is attached to at least one of the first layer and the second layer;
The breather filter assembly of claim 1, wherein the first layer is configured to bend away from the second layer to create an air gap between the first layer and the third layer.   The breather filter assembly of claim 1, wherein the valve is a passive valve.   The breather filter assembly of claim 1, wherein the filter media absorbs water vapor.   The breather filter assembly of claim 1, wherein the filter medium comprises a water-absorbable polymer that is expandable with water.   The breather filter assembly according to claim 1, wherein the first layer and the second layer include a substantially non-permeable polymer membrane.   The breather filter assembly of claim 1, wherein the first layer defines a plurality of openings.   The breather filter assembly of claim 1, wherein the second layer defines a plurality of openings.   The breather filter assembly of claim 1, wherein the third layer is annular.   The breather filter assembly of claim 1, wherein the first layer has a peripheral edge and the second layer has a peripheral edge attached to the peripheral edge of the first layer. . A breather filter assembly,
A substrate layer;
The valve layer,
A filter media layer disposed between the substrate layer and the valve layer;
The valve layer is
A first layer defining a plurality of inner pores;
A second layer defining an outer flap;
The first layer is adjacent to the second layer;
The outer flap is disposed on the plurality of inner pores;
A breather filter assembly, wherein the outer flap is configured to bend away from the plurality of inner pores.   The second layer defines a plurality of outer pores and an inner flap, the inner flap is disposed above the plurality of outer pores, and the outer flap is bent away from the inner pore. The breather filter assembly of claim 10, wherein the breather filter assembly is constructed.   The breather filter assembly of claim 10, further comprising a liquid composition disposed between the first layer and the second layer.   The breather filter assembly of claim 10, wherein the filter media comprises activated carbon.   The breather filter assembly according to claim 10, wherein the first layer and the second layer include a polymer membrane that is substantially impermeable.   The breather filter assembly of claim 10, wherein the filter media absorbs water vapor. A breather filter for an electronic device container,
A first layer defining an opening;
A second layer;
A filter element disposed between the first layer and the second layer;
A valve assembly including a first side and a second side;
Have
The valve assembly is attached to the first layer;
The valve assembly has an open configuration and a closed configuration;
The valve assembly is configured to change from the closed configuration to the open configuration when an air pressure difference between the first side and the second side exceeds a threshold. Breather filter.   The breather filter of claim 16, wherein the valve assembly comprises a passive valve.   The breather filter according to claim 16, wherein the filter element absorbs water vapor.   The breather filter according to claim 16, wherein the second layer includes a membrane that allows fluid flow.   The breather filter according to claim 19, wherein the second layer includes an expanded polytetrafluoroethylene membrane.

Images