Contaminant control filter with fill port

Filters, methods, and an apparatus for filling housings and both encapsulated porous and non-porous spaces with contaminant control media for placement in electronic enclosures, such as disk drive enclosures, are disclosed. In one embodiment, a filter assembly includes a housing comprising an internal cavity configured to receive contaminant control media, a fill port in communication with the internal cavity, and an opening in communication with the internal cavity, and filter media at least partially covering the opening; and contaminant control media occupying the internal cavity. Contaminant control media is deposited within the internal cavity via the fill port by means of creating a negative pressure within the internal cavity. The application of a partial vacuum facilitates movement of the contaminant control media into the internal cavity and minimizes the contamination of the filter, housing, and work space common to other loose fill filling methods. Other aspects and embodiments are provided herein.

TECHNICAL FIELD

The present invention relates to a filter construction, an apparatus for making the filter construction, and methods for making the filter construction.

BACKGROUND OF THE INVENTION

Contaminant control and recirculation filters have a variety of uses, including uses in electronic equipment. In the computer industry, contaminant control and recirculation filters are used within enclosures for electronic devices to protect the electronic components from particulate and gaseous contaminants. For example, disk drives often include contaminant control and recirculation filters within the disk drive enclosure to protect the drive components and the disks from contaminants including water vapor, organic vapor, and out-gassing. Without such protection, these contaminants can lead to stiction, corrosion, and, in some instances, drive failure.

Frequently, contaminant control and recirculation filters have either a loose fill contaminant control (see U.S. Pat. No. 6,077,335) or a compression molded contaminant control of various configurations (see, e.g., U.S. Pat. No. 5,876,487 or U.S. Pat. No. 6,146,446). Each of these configurations offers distinct advantages and disadvantages. A loose fill contaminant control media is generally less expensive than one that is compression molded. However, loose fill contaminant control media is difficult to manipulate due to its granular or beaded nature, and can cause contamination of the clean room, the filter housing, and the surfaces that require welding after deposition of the loose fill contaminant control media. Compression molded contaminant controls are generally easier to handle and are cleaner to use in a clean room environment. However, they are more expensive, require tooling that adds to cost and labor time, and are much less efficient in contaminant adsorption. Clearly, a new filter design which overcomes these challenges would be desirable.

SUMMARY OF THE INVENTION

Generally, the present invention relates to adsorbent or recirculation filters for placement in an electronic enclosure, such as a hard disk drive, methods of filling these filters with a contaminant control media, and an apparatus capable of accomplishing the filling.

In an embodiment, the invention includes a method for filling a filter assembly with a contaminant control media comprising the steps of: providing a housing containing an internal cavity, at least one fill port formed in the housing and in communication with the internal cavity of the housing, and an opening with filter media at least partially covering the opening; providing contaminant control media; creating a negative pressure with the internal cavity by drawing a partial vacuum within the cavity; and drawing the contaminant control media into the internal cavity under partial vacuum. In addition to drawing in the adsorbent, the partial vacuum also prevents dust created during handling the adsorbent or filling the cavity from escaping and contaminating the manufacturing room. The filter media can comprise ePTFE, the contaminant control media can comprise an adsorbent material and neutralization material, and the filter assembly can be configured for insertion into an electronic enclosure.

In an embodiment, the invention includes a method for filling a porous filter assembly with a contaminant control media, comprising the steps of: providing a porous container at least partially formed of filter media; providing the contaminant control media; drawing a partial vacuum across the porous container; and drawing the contaminant control media into the porous container under partial vacuum. The filter media can comprise ePTFE and the contaminant control media can comprise an adsorbent material and neutralization material. The porous container can comprise a filter bag or a molded housing and the filter assembly can be configured for insertion into an electronic enclosure.

In an embodiment, the invention includes a filter assembly for use in an electronic enclosure including a housing comprising: an internal cavity within the housing, the internal cavity configured to receive contaminant control media, at least one fill port in communication with the internal cavity, an opening in communication with the cavity, and filter media at least partially covering the opening. Contaminant control media occupies the internal cavity. The filter media can comprise ePTFE and the contaminant control media can comprise an adsorbent material and neutralization material. The filter assembly can be configured for insertion into an electronic enclosure.

In an embodiment, the invention includes a delivery apparatus comprising: a holding unit configured to retain contaminant control media; an assembly configured to deposit contaminant control media into an encapsulated space; and a device capable of creating a negative pressure within the encapsulated space to facilitate movement of the contaminant control media into the encapsulated space and to prevent the escape of any dust (aerosol) created during the filling.

This summary of the present invention is merely an overview of some of the teachings of the present application and is not intended to describe each disclosed embodiment or every implementation of the present invention. Further embodiments will be found in the figures, detailed description, and claims. The scope of the present invention should be determined by the appended claims and their legal equivalents.

While the invention is susceptible to various modifications and alternative forms, specifics thereof have been shown by way of example and drawings, and will be described in detail. It should be understood, however, that the invention is not limited to the particular embodiments described. On the contrary, the intention is to cover modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is applicable to filters and methods of making and using filters to filter a fluid, such as, for example, air or other gases. The filter construction can reduce contaminants within an electronic enclosure, such as a disk drive housing, by a variety of processes. One process for reducing, removing, or preventing contamination within the disk drive housing is to reduce or remove contaminants entering the disk drive housing from regions outside of the disk drive housing (or other device). The breather embodiment of the filter construction is constructed for this purpose. A second process for reducing, removing or preventing contamination from within the disk drive housing is to reduce or remove contaminants present in the disk drive housing atmosphere. The recirculation embodiment of the filter construction, can be constructed for this purpose. In addition, an adsorbent assembly can be used to remove contaminants from the inside of a drive. The adsorbent assembly contains contaminant control media, and is placed within the electronic enclosure, but does not have a recirculation function and does not communicate by a breather hole with the exterior of the enclosure. However, the adsorbent assembly still removes contaminants from the drive interior.

In one embodiment, the invention includes a method for filling a filter assembly with a contaminant control media under partial vacuum in a fashion such that the filter assembly is filled with minimal external contamination. In such embodiments the method comprises the steps of providing a housing containing an internal cavity, at least one fill port in communication with the internal cavity, and an opening with filter media at least partially covering said opening. An air flow through the fill hole is created by applying a partial vacuum to the outside of the porous media and this air flow helps draw in the contaminant control media and prevents dust from escaping through the fill hole. The filter media can comprise ePTFE, the contaminant control media can comprise an adsorbent material and neutralization material, and the filter assembly can be configured for insertion into an electronic enclosure.

The filter construction generally includes a particulate or solid removal element and a contaminant control element. Examples of particulate or solid removal elements include, but are not limited to, filter materials such as polymers, non-woven materials, fibers, paper, and the like. Examples of contaminant control elements include, but are not limited to, adsorbent material, neutralization material, and the like. Additionally or alternatively, a tortuous or extended path, such as a diffusion channel, can be used to restrict contaminant entry into the electronic enclosure when the filter construction is used as a breather filter.

Various aspects of the invention will now be discussed in reference to the figures. Referring toFIGS. 1 and 2, one embodiment of the invention includes a filter assembly10comprising a housing40having a top20, base30, sidewall24, and filter media50secured to the top20. AlthoughFIGS. 1 and 2depict the housing40as generally cylindrical in shape, it will be appreciated that various embodiments can include multiple sidewalls defining various shape and sizes of the filter assembly10. For example, the housing40can be rectangular, oval, square, circular, triangular, or generally any other shape desired.

In many applications the housing will be constructed such that it is customized for a specific electronic enclosure, so that it fits within an appropriate portion of the enclosure without interfering with other equipment within the enclosure. For example, when placed within a disk drive assembly, the filter assembly10having housing40must avoid contact with the spinning disks and read/write head of the disk drive, while also allowing adequate clearance with these moving parts to avoid creating undesirable air turbulence. One of the benefits of the present invention is that it allows a wide variety of shapes and sizes of filter assemblies10to be manufactured with minimal retooling for different assembly configurations.

AlthoughFIGS. 1 and 2depict the filter media50as generally a circular shape covering the majority of the top20, it will be appreciated that the filter media50can be of any shape and can cover different sizes, areas, and dimensions (including one or more sidewall(s) and the base30) of the filter assembly10. It will be appreciated that the filter media50can be secured with a variety of methods including, but not limited to, mold casting, welding, adhesives, mechanical connections, and the like.

FIG. 3portrays a bottom plan view of the embodiment of the filter assembly shown inFIGS. 1 and 2. The base30of the filter assembly10defines a fill port60(indicated by phantom circle). The fill port60is used to fill the internal cavity of the housing40with contaminant control media90(shown inFIG. 5). After the internal cavity of the housing40is filled, the fill port60can be sealed. In one embodiment of the invention, the fill port60is sealed with an adhesive mounting label70.

The mounting label70, serves a dual purpose in the embodiment of the invention shown inFIGS. 1,2,3,4, and5. The mounting label70both seals the fill port60and holds the filter assembly10in the electronic enclosure. The mounting label70can be, for example, a double-sided adhesive film that includes an adhesive carrier with adhesive disposed on both sides. In such embodiments the mounting label70can both seal the fill port60during manufacture and later secure the filter assembly10to a mounting surface, such as the interior wall of a hard disk drive. The adhesive carrier is typically a polymer film, such as, for example, a polyethylene, polypropylene, polyester, polycarbonate, polyurethane, or polyvinyl chloride film. Suitable adhesives include, but are not limited to, epoxies, resins, pressure-sensitive adhesives, hot-melt adhesives, solvent-based adhesives, emulsion-based adhesives, and contact adhesives. One example of a suitable adhesive is 3M 502FL adhesive from 3M Co. (St. Paul, Minn.).

It will be appreciated that the fill port60can also be sealed with a variety of other methods including, but not limited to, snug fit plugs, filter media, ultrasonic welding, and the like. If a mounting label70is not used, an additional adhesive media may be necessary. Or, in the alternative, the filter assembly10can be held in the electronic enclosure by mechanical techniques, including, but not limited to, clips, frames, welding, or the like. AlthoughFIG. 3depicts the fill port60as generally a circular shape, it will be appreciated that the fill port60can be any shape.

Referring again toFIG. 3, in the depicted embodiment of the invention the base30of the filter assembly10defines a breather port80. The breather port80permits the flow of fluid from the outside of the electronic enclosure into the electronic enclosure. The breather port80allows the flow of air to come into contact with the contaminant control media90disposed within the internal cavity of the filter housing40prior to the flow of air exiting the filter assembly10. AlthoughFIG. 3depicts the breather port80as generally a circular shape, it will be appreciated that the breather port80can be of any shape. Also, although not depicted herein, the breather port can be connected to a diffusion channel, molded into the base70, formed by one or more thin films, or formed within the surface on which the filter assembly10is ultimately mounted (such as the interior wall of a disk drive).

FIG. 4portrays a schematic side view of the embodiment of the invention shown inFIGS. 1,2, and3. The mounting label70can be seen present on the base30of one embodiment of the invention.

FIG. 5portrays a cross-sectional view of the embodiment of the invention shown inFIG. 1 to 4, with the cross section taken along line A-A′ ofFIG. 2. The filter media50is secured to the top20. The base30of the housing40defines the fill port60that has been sealed by the mounting label70, and the base30of the housing40in conjunction with the mounting label70helps further define the breather port80. The housing40also defines the internal cavity within which the contaminant control media90is deposited via the fill port60. It will be appreciated that the contaminant control media90is of sufficient size, shape, or composition that it is unable to escape through the breather port60in the embodiment depicted. Thus, for example, if the breather port is 2 mm in diameter, then it would be desirable to use contaminant control media that is 3 mm in diameter (or at least greater than 2 mm in diameter). In the alternative a scrim or other material can be placed over the interior or exterior of the breather port to prevent escape of the contaminant control media. Further detailed discussion of the contaminant control media can be found below.

FIG. 6portrays an inverted cross sectional view of one embodiment of the invention, prior to filling the housing with contaminant control media. The filter assembly110is defined by a housing140having a top120, base130, sidewall124, and filter media150secured to the top20. The base130of the housing140defines a fill port160and a breather port180.

FIGS. 7-10portray a schematic diagram, and mechanism of operation, of one embodiment of a filling apparatus capable of loading contaminant control media into the housing of a filter assembly. The filling apparatus191includes contaminant control media190placed within a loading unit192. The filling apparatus191further comprises a loading station194where the housing140for the filter assembly110will be placed. The loading station194will also be capable of drawing a vacuum across a surface of the housing140containing filter media150and therefore will further comprise a vacuum generating apparatus. The loading station194will further contain a coupling device196for attaching the housing140to the loading station194and for facilitating the creation of a seal sufficient to draw a partial vacuum across a surface of the housing140containing filter media150.

FIG. 8portrays the filling apparatus191where the loading station194is occupied by a housing140for the filter assembly110found inFIG. 6. The loading unit192is engaged with the housing140at the fill port160on the base130and is capable of depositing the contaminant control media190into the internal cavity of the housing140. To facilitate delivery of the contaminant control media190, a partial vacuum will be drawn across the filter media150; the vacuum generating apparatus being coupled to the loading station194and the seal for drawing the vacuum across filter media150being facilitated by the coupling device196located on the loading station194. It will be appreciated that in this embodiment the breather port180must be sealed in order to generate the partial vacuum and in this embodiment, the loading unit192is capable of sealing the breather port180. It will be appreciated that the breather port180can also be sealed with any other temporary mechanism, for example, a removable adhesive tape or label.

FIG. 9portrays the loading apparatus loading contaminant control media into the internal cavity of the filter assembly fromFIG. 6; the task being partially completed. The application of a partial vacuum facilitates movement of the contaminant control media190from the loading unit192, through the filler port160on the base130of the housing140, and into the internal cavity of the housing140of the filter assembly110. A seal sufficient to create a partial vacuum is created by 1) temporarily sealing the breather port180and 2) the coupling device196of loading unit194creating a seal across the filter media150of the housing140.

FIG. 10portrays the loading apparatus loading contaminant control media into the internal cavity of the filter assembly; the task being completed. The internal cavity of the housing140of the filter assembly110can be completely and efficiently filled with contaminant control media190because of the application of a partial vacuum across the filter media150of the housing140and the temporary sealing of the breather port180.

It will be appreciated thatFIGS. 7-10only represent a single, simplified schematic of the filling apparatus191and that various embodiments of the filling apparatus will exist to fill various embodiments of the filter assembly. The general purpose of the filling apparatus is to provide a mechanism to fill the internal cavity of a filter housing with contaminant control media. The contaminant control media is drawn into the internal cavity of the filter housing by drawing a partial vacuum on at least a portion of one surface of the filter housing at least partially covered with secured filter media.

FIG. 11portrays the housing for the filter assembly ofFIGS. 6 to 10in an inverted position, after the filter assembly has been removed from the loading apparatus. The internal cavity of the housing140of filter assembly110is completely occupied by the contaminant control media190that was loaded via the fill port160. It will be appreciated that in this embodiment the contaminant control media190is of sufficient size, shape, or composition that is unable to escape the internal cavity of the housing140of the filter assembly110via the breather port180.

FIG. 12Aportrays the filter assembly110in an upright position after a mounting label has been attached to the base130of the housing140. The mounting label170closes the fill port160; thereby preventing the contaminant control media190from escaping the internal cavity of the housing140. The mounting label170further defines the breather port180located on the base130of the housing140of the filter assembly110. The mounting label170can be, for example, a double-sided adhesive film that includes an adhesive carrier with adhesive disposed on both sides. One adhesive surface can bind to the base130of the filter assembly110and the second adhesive surface can be protected by a release liner174. The release liner174can be removed, thereby exposing a second adhesive surface that can be used to secure the filter assembly110to an internal surface of an electronic enclosure.

FIG. 12Bportrays a bottom plan view of the filter assembly ofFIG. 12A. The base130of the housing140of the filter assembly110defines the breather port180and the fill port160(indicated by phantom circle). The base130is partially covered by a mounting label170that can be, for example, a double-sided adhesive film that includes an adhesive carrier with adhesive disposed on both sides. The mounting label170seals the fill port160, while allowing the breather port180to maintain fluid communication with the external environment. The mounting label170further comprises a release liner174that protects the second adhesive surface from environmental exposure. The release liner174can be removed, thereby exposing the second adhesive surface that can then be use to secure the filter assembly110to an internal surface of an electronic enclosure. It will be appreciated that although the fill port160and breather port180are depicted as generally circular, they can be of any shape.

FIG. 13portrays the filter assembly ofFIGS. 6-12where the filter assembly is mounted within an electronic enclosure. The filter assembly110is secured within the electronic enclosure105via the mounting label170. The release liner174ofFIG. 12Bhad been removed, exposing the second adhesive surface, and said surface is used to secure the filter assembly110to the electronic enclosure105. The filter assembly110is in fluid communication with the external environment via the breather port180. It will be appreciated that that contaminant control media190is of a sufficient size, shape, or composition that it is unable to escape via the breather port180. In this embodiment of the invention, the filter assembly110serves as an adsorbent breather filter.

FIG. 14Aportrays a schematic cross sectional view of another embodiment of the invention where the fill port is configured for use as the breather port. Thus, the fill port is initially used to fill the housing with contaminant control media, after which the port's diameter is typically reduced to prevent escape of the contaminant control media, but to still allow the fill port to function as a breather port. In alternative to reducing the diameter of the fill port, it is possible to place a porous media or scrim over the fill port to retain contaminant control media. The internal cavity of the housing240of the filter assembly210contains the contaminant control media290. The contaminant control media290is loaded into the internal cavity of the housing240via the fill port260found on the base230of the filter assembly210. The housing240further comprises a top220to which filter media250is secured. In this embodiment of the invention, a mounting label270is affixed to the base230to decrease the diameter of the fill port260.

The diameter of the fill port260should be decreased so that 1) the fill port260can be configured into the breather port and 2) the contaminant control media290does not escape through the fill port260. It will be appreciated that that contaminant control media290is of a sufficient size, shape, or composition, that it is unable to escape via the breather port. The mounting label270can be, for example, a double-sided adhesive film that includes an adhesive carrier with adhesive disposed on both sides. The mounting label270will further allow the filter assembly210to be secured within an electronic enclosure.

FIG. 14Bportrays a bottom plan view of the filter assembly ofFIG. 14A. The base230of the filter assembly210defines a fill port260(indicated by phantom circle). Initially, the fill port260is used to fill the internal cavity of the housing240with contaminant control media290; later the fill port260is configured into the breather port (indicated by the intact circle within the phantom circle that defined the fill port260) by the addition of the mounting label270. The mounting label270sufficiently decreases the size of the fill port260so that the contaminant control media290cannot escape. Additionally, the mounting label270will allow the filter assembly210to be secured within an electronic enclosure. It will be appreciated that although the fill port260and breather port are depicted as generally circular, they can be of any shape. In this embodiment of the invention, the filter assembly210serves as an adsorbent breather filter.

FIG. 15Aportrays another embodiment of the invention where the fill port is completely sealed and there is no breather port. The internal cavity of the housing340of the filter assembly310contains the contaminant control media390. The contaminant control media390was loaded into the internal cavity of the housing340via the fill port360found on the base330of the filter assembly310. The housing340further comprises a top320to which filter media350is secured. The base330is partially covered by a mounting label370that can be, for example, a double-sided adhesive film that includes an adhesive carrier with adhesive disposed on both sides. The mounting label370seals the fill port360after the contaminant control media390has been loaded into the internal cavity of the housing340. The mounting label370can further comprise a release liner that protects the second adhesive surface from environmental exposure. The release liner can be removed, thereby exposing the second adhesive surface, and the entire filter assembly310can be secured to an internal surface of an electronic enclosure. The assembly ofFIG. 15Ais particularly useful as an adsorbent assembly within an electronic enclosure.

FIG. 15Bportrays a bottom plan view of the filter assembly ofFIG. 15A. The base330of the filter assembly310defines a fill port360(indicated by phantom circle). This fill port360is used to fill the internal cavity of the housing340with contaminant control media390. The mounting label370is affixed to the base330of the filter assembly310to seal the fill port360. This embodiment of the invention lacks a breather port and therefore can be used as an adsorbent filter.

FIG. 16Aportrays another embodiment of the filter assembly where the fill port is positioned on a side wall of the filter assembly. The internal cavity of the housing440of the filter assembly410contains the contaminant control media490. The contaminant control media490was loaded into the internal cavity of the housing440via the fill port460found on the sidewall424of the filter assembly410. The housing440further comprises a top420to which filter media450is secured.

The base430is partially covered by a mounting label470that can be, for example, a double-sided adhesive film that includes an adhesive carrier with adhesive disposed on both sides. The mounting label470is used to secure the filter assembly410to a mounting surface, such as the interior surface of an electronic enclosure. The fill port460can be sealed with an adhesive label464and can be, for example, a single sided adhesive film that includes an adhesive carrier with adhesive disposed on a single side. In an alternative embodiment, the fill port460can be designed so that it can be sealed with tight fitting plug.

FIG. 16Bportrays a bottom plan view of the filter assembly ofFIG. 16A. To the base430of the housing440of the filter assembly410is affixed a mounting label470. The mounting label470can further comprise a release liner that protects the second adhesive surface from environmental exposure. The release liner can be removed, thereby exposing the second adhesive surface, and the entire filter assembly410can be secured to an internal surface of an electronic enclosure. On the sidewall424of the housing440is the fill port460ofFIG. 16Athat can be sealed with an adhesive label464. It will be appreciated that although the filter assembly410in this embodiment is cubical in shape, the filter assembly410can be of any shape. This embodiment of the invention lacks a breather port and therefore can be used as an adsorbent filter.

FIG. 17Aportrays another embodiment of the invention where filter media is secured to two dimensions of the filter assembly. The internal cavity of the housing540of the filter assembly510contains the contaminant control media590. The contaminant control media590was loaded into the internal cavity of the housing540via the fill port560found on the sidewall524of the filter assembly510. The housing540further comprises a top520and base530to which filter media550is secured. It will be appreciated that the filter media550can be secured with a variety of methods including, but not limited to, mold casting, welding, adhesives, mechanical connections, and the like. It will be further appreciated that the filter assembly510can be held in the electronic enclosure by mechanical techniques, including, but not limited to, clips, frames, welding, or the like. The fill port560can be sealed with an adhesive label564that can be, for example, a single sided adhesive film that includes an adhesive carrier with adhesive disposed on a single side. In an alternative embodiment, the fill port560can be designed so that it can be sealed with tight fitting plug.

FIG. 17Bportrays a top plan view of the filter assembly ofFIG. 17A. The top520of the housing540of the filter assembly510partially comprises secured filter media550. The fill port560ofFIG. 17Alocated on sidewall424is sealed with an adhesive label464. It will be appreciated that although the filter assembly510in this embodiment is cubical in shape, the filter assembly410can be of any shape. This embodiment of the invention lacks a breather port and therefore can be used as an adsorbent filter.

FIG. 18Aportrays another embodiment of the invention where the secured filter media and the fill port are located on the same surface of the filter assembly. The internal cavity of the housing640of the filter assembly610contains the contaminant control media690. The contaminant control media690was loaded into the internal cavity of the housing640via the fill port660found on the same surface upon which the secured filter media650is positioned. The fill port660, inFIG. 18A, is shown “unsealed”. A weld horn, in conjunction with ultrasonic welding, can be used on the protrusions664of the fill port660to seal the filter assembly610. The housing640further comprises a top620to which filter media650is secured and a base630that defines a breather port680. The breather port is further defined by a mounting label670. The base630is partially covered by a mounting label670that can be, for example, a double-sided adhesive film that includes an adhesive carrier with adhesive disposed on both sides. The mounting label670is used to secure the filter assembly610to a mounting surface, such as the interior surface of an electronic enclosure.

FIG. 18Bportrays a top plan view of the filter assembly ofFIG. 18A. The top620of the housing640of the filter assembly610partially comprises secured filter media650. The fill port660ofFIG. 18Alocated on the top620and has been sealed with a weld horn in conjunction with ultrasonic welding. It will be appreciated that although the filter assembly610in this embodiment is generally oval in shape, the filter assembly610can be of any shape. This embodiment of the invention can be used as a breather adsorbent filter.

FIG. 19Aportrays another embodiment of the invention where the secured filter media and the fill port are located on the same surface of the filter assembly and a scrim that covers the breather port is located within the internal cavity of the housing. The internal cavity of the housing740of the filter assembly710contains the contaminant control media790. The contaminant control media790was loaded into the internal cavity of the housing740via the fill port760found on the same surface upon which the secured filter media750is positioned. The fill port760can be sealed with an adhesive label764that can be, for example, a single sided adhesive film that includes an adhesive carrier with adhesive disposed on a single side.

In an alternative embodiment, the fill port760can be designed so that it can be sealed with tight fitting plug. The housing740further comprises a top720to which filter media750is secured and a base730that defines a breather port780. The breather port is further defined by a mounting label770. The base730is partially covered by a mounting label770that can be, for example, a double-sided adhesive film that includes an adhesive carrier with adhesive disposed on both sides. The mounting label770is used to secure the filter assembly710to a mounting surface, such as the interior surface of an electronic enclosure. Within the housing740, adjacent to the base730, and above the breather port780, is placed a scrim752. This scrim752can be composed of similar material as the filter media750and the scrim752can function to filter the incoming fluid or prevent the contaminant control media790from escaping through the breather port780.

In the embodiment portrayed inFIG. 19B, the scrim752defines a diffusion channel756and a breather port780. The diffusion channel756provides a tortuous or extended path that can be used to restrict contaminant entry into the electronic enclosure. The diffusion channel756can be formed as a straight or curved path. Alternatively, the diffusion channel756may be formed to have a more complex path, such as a winding path or a spiral path. For example, the diffusion channel can be configured as an inwardly spiraling channel, an outwardly spiraling channel, or as a maze-like configuration. The diffusion channel756can, in some embodiments, have two or more branches.

Examples of diffusion channels for use with computer disk drive systems are described in U.S. Pat. No. 4,863,499, incorporated herein by reference. Other examples of a diffusion channels defined by diffusion channel layer of film are described in U.S. Pat. No. 5,997,614, incorporated herein by reference. Fluid enters the breather port780, travels through diffusion channel756, and then enters the internal cavity of the filter housing740. Fluid can also travel through this pathway in the reverse direction depending on relative air pressure.

Referring again toFIG. 19B, the base730includes a scrim752. The scrim752defines the diffusion channel756. The boundary layer754can be formed using a polymer or metallic film or a plastic layer. The boundary layer754is typically nonporous and has a low permeability to the fluid to be filtered, particularly, at the fluid pressures expected for operation of the filter assembly710. Examples of suitable polymer films for use in the boundary layer754include polyester (e.g., Mylar), polyethylene, polypropylene, nylon, polycarbonate, polyvinyl chloride, and polyvinyl acetate films. Preferably, the polymer films have relatively low or no out-gassing. Suitable metallic films for use in the diffusion boundary layer754include films formed using metals, such as, for example, copper and aluminum, and alloys, such as, for example, stainless steel. Preferred metal films do not significantly corrode or form reaction products (e.g., rust) that can be dislodged from the film under the expected operating conditions of the filter. In some embodiments, the metallic film may be deposited or otherwise formed on a base material, such as, for example, a polymer film.

FIG. 19Cportrays a top plan view of the filter assemblies ofFIGS. 19A and 19B. The top720of the housing740of the filter assembly710partially comprises secured filter media750. The fill port760can be sealed with an adhesive label764that can be, for example, a single sided adhesive film that includes an adhesive carrier with adhesive disposed on a single side. In an alternative embodiment, the fill port760can be designed so that it can be sealed with tight fitting plug. It will be appreciated that although the filter assembly710in this embodiment is generally oval in shape, the filter assembly710can be of any shape. This embodiment of the invention can be used as a breather adsorbent filter

FIG. 20portrays a top plan view of another embodiment of the invention. Arrows show fluid entering the filter assembly810through one secured filter media850and exiting the filter assembly810housing840through a second secured filter media850. The housing840further defines a top820upon which a fill port860is located; the fill port860being used to deposit contaminant control media within the internal cavity of the housing840. In alternative embodiments, the fill port860can be located on the base or the sidewall of the housing840. The fill port860can be sealed with an adhesive label864that can be, for example, a single sided adhesive film that includes an adhesive carrier with adhesive disposed on a single side. In an alternative embodiment, the fill port860can be designed so that it can be sealed with tight fitting plug. In this embodiment, the invention can be used as a recirculation filter.

In an alternative embodiment ofFIG. 20, the invention further comprises a base that can define a breather port that is in fluid communication with both the internal cavity of the housing of the filter assembly and the external environment. In this embodiment, the invention can be used as a breather recirculation filter. In an alternative embodiment ofFIG. 20, the invention further comprises a breather port and diffusion channel. In this embodiment, the invention can be used as a breather recirculation filter.

Contaminant Control Material

Typically, the contaminant control media is disposed within the internal cavity of the housing or within a porous or non-porous encapsulated space. The contaminant material can be any suitable material for the removal, reduction, entrapment, immobilization, adsorption, absorption, and neutralization of contaminants.

The contaminant control media is typically provided for the removal of chemical contaminants. The contaminant control media can remove contaminants from the air entering the enclosure atmosphere or already present within the enclosure atmosphere by adsorption, neutralization, or immobilization. As used throughout this application, the terms “adsorb,” “adsorption,” “adsorbent” and the like, are intended to also include the mechanism of absorption. Typically, the contaminant control media is selected to be stable and adsorb or neutralize contaminants within normal disk drive operating temperatures, for example, within a range of about −40° C. to 100° C.

The contaminant control media adsorbs or neutralizes one or more types of contaminants, including, for example, water, water vapor, acid gas, and volatile organic compounds. The contaminant control media can include adsorbent material (physisorbent or chemisorbent material), such as, for example, a desiccant (i.e., a material that adsorbs or absorbs water or water vapor) or a material that adsorbs or absorbs volatile organic compounds, acid gas, or both. Suitable adsorbent materials include, for example, activated carbon, activated alumina, molecular sieves, silica gels, potassium permanganate, calcium carbonate, potassium carbonate, sodium carbonate, calcium sulfate, or mixtures thereof. Carbon is suitable for most implementations, and carbon suitable for use with the present invention is disclosed in U.S. Pat. No. 6,077,335, incorporated herein by reference in its entirety.

Additionally, contaminant control media can include neutralization material. Neutralization material can include acid or base impregnated substances that can effectively neutralize the gaseous contaminants found within the housing or electronic enclosure. Neutralization material can also include enzyme or catalyst impregnated substances that increase the rate of degradation of the gaseous contaminants found with the housing or electronic enclosure.

Although contaminant control media can be manufactured from a single substance, mixtures of materials are also useful, for example, silica gel can be blended with carbon particles. In some embodiments, the contaminant control media includes layers or combinations of materials, so that different contaminants are selectively removed as they pass through or by the different materials.

It will be appreciated that, contaminant control media can undertake many forms including powdered (passes through 100 mesh), granular (passes through 28 to 200 mesh), beads, slurry, paste and any combination thereof.

Filter Media

Filter media of the present invention may contain one or more particulate filter layers to prevent particulate contaminants from entering the electronic enclosure from the filter assembly. Such particulate contaminants may originate outside of the electronic enclosure or may be shed from the contaminant control media. Filters of the present invention may also include particulate filter layers to prevent particulate contaminants from entering the filter assembly from outside of the electronic enclosure. They may be disposed on the outside of the filter assembly or disposed inside of the filter assembly.

The filter media may comprise a variety of porous or microporous membranes. The size of the pores in the membranes and the thickness of the membranes often determine, at least in part, the size of particles allowed through the membrane and filter.

Often the porous or microporous membranes are formed from polymers. Examples of suitable porous or microporous membranes include porous or microporous polyethylene, polypropylene, nylon, polycarbonate, polyester, polyvinyl chloride, polytetrafluoroethylene (PTFE), and other polymeric membranes. An especially suitable filtering layer is expanded polytetrafluoroethylene (ePTFE) because of its good filtration performance, conformability to cover adsorbent layers, and cleanliness. A preferred ePTFE membrane has a filtration efficiency of 99.99% at 0.1 micrometer diameter sized particles with a resistance to airflow of approximately 20 mm water column at an airflow of 10.5 feet per minute face velocity. ePTFE is commercially available under the registered trademark GORE-TEX by W. L. Gore & Associates, Inc.

In one embodiment, the filter assembly is shown with a porous support layer disposed within the internal cavity of the filter housing. The contaminant control media is disposed on the porous support layer. For example, a mesh or scrim can be used as the porous support layer to hold the contaminant control media. Polyester and other suitable materials (such as polypropylene, polyethylene, nylon and PTFE) can be used as the mesh or scrim. The porous support layer can be used as a base on which the adsorbent media is disposed.

Typically, any porous support layer is not more than about 40% of the weight of the adsorbent material, and is generally about 10 to 20% of the total filter media weight.

Filter Housing

The filter housing may be, for example, an outer covering, a casing, or a shell. The housing is typically formed from a plastic material, such as, for example, polycarbonate, polyvinyl chloride, nylon, polyethylene, polypropylene, or polyethylene terephthalate. The housing may be a single piece or, alternatively, the housing may be formed as two or more pieces that are combined together using, for example, an adhesive, mechanical connectors, heat sealing, and ultrasonic welding to form, for example, a perimeter seal.

It should be noted that in the context of this invention the reference to the “reduction” or “removal” of contaminants refers to the clarification of a fluid (e.g., gas or liquid) being filtered. The fluid being clarified in a hard disk drive enclosure is typically an air stream. It should be appreciated, however, that streams of other gases or liquids could also be clarified by the filter construction of the present invention. The reduction or removal of contaminants from a liquid or gas stream by a filter construction can also be referred to as entrapment, immobilization, adsorption, absorption, neutralization, or otherwise binding (e.g., by covalent, ionic, coordinative, hydrogen, or Van der Waals bonds, or combinations thereof) of the contaminants inside or on the surface of the filter construction.

This application is intended to cover adaptations or variations of the present subject matter. It is to be understood that the above description is intended to be illustrative, and not restrictive. The scope of the present subject matter should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.