Low diffusion disk drive breather vent

Abstract

.[.A vent cap has.]. .Iadd.A low diffusion disk drive breather vent for communicating air between the interior and the exterior of a sealed disk drive housing through a vent passageway, .Iaddend.a long, narrow air communication passage .[.covering the vent outlet of a sealed disk drive. The passage reduces.]. .Iadd.provided to reduce .Iaddend.diffusion of water vapor .[.into the disk drive.]. .Iadd.through the passage.Iaddend..

I claim: 
     
       1. .[.A.]. .Iadd.In an .Iaddend.apparatus for communicating air between the interior and exterior of a sealed disk drive housing while reducing communication of water vapor between the interior and exterior of said disk drive housing.Iadd., said disk drive housing having a disk drive mounted in the interior thereof, the improvement .Iaddend.comprising: .[.a sealed disk drive housing having an interior and an exterior;.].   .[.a disk drive mounted in the interior of said housing;.].   a vent outlet mounted on said sealed disk drive housing and having a passageway communicating between the interior and exterior of said sealed disk drive housing;   a vent cap having exterior and interior surfaces, said cap being mounted over the vent outlet with the interior surface facing said vent outlet passageway;   means for forming an airtight seal between the .[.exterior surface of the.]. cap and the vent passageway; and   a .[.long, narrow.]. passage communicating between the exterior and interior surfaces of said cap, the length and cross section of the passage being arranged to provide airpressure equalization and reduced water vapor communication between the interior and exterior of the housing, the passage .[.generally tracking the circumference of the cap and.]. having a length .[.at least equal to the circumference of the cap.]. and a cross section minimum determined by the length of the passage and a predetermined minimum pressure differential between the interior and exterior of the disk drive housing at a predetermined airflow rate, the passage length further being long enough such that such minimum cross section is large enough that the flow of air and water vapor in the passage is essentially laminar.   
     
     
       2. .Iadd.In an .Iaddend..[.Apparatus.]. .Iadd.apparatus.Iaddend.pparatus for communicating air between the interior and exterior of a sealed disk drive housing while reducing communication of water vapor between the interior and exterior of said disk drive housing.Iadd., said disk drive housing having a disk drive mounted in the interior portion thereof, the improvement .Iaddend.comprising: .[.a sealed disk drive housing having an interior and an exterior;.].   .[.a disk drive mounted in the interior of said housing;.].   a vent outlet mounted on said sealed disk drive housing and having a passageway communicating between the interior and exterior of said sealed disk drive housing;   a gasket mounted about the passageway; and   a vent cap having ridges forming a .[.long, narrow.]. groove between an inlet opening and an outlet opening, said cap being mounted on said vent outlet with said ridges pressed against said gasket and forming an airtight seal therewith such that the groove provides a communicating passage between the vent passageway and the exterior of said disk drive housing, the length and cross section of the groove being arranged to provide air-pressure equalization and reduced water vapor communication between the interior and exterior of the housing, the passage .[.generally tracking the circumference of the cap and having a length at least equal to the circumference of the cap and a cross section minimum determined by the length of the passage and.]. .Iadd.having a length and cross section so as to provide .Iaddend.a predetermined minimum pressure differential between the interior and exterior of the disk drive housing at a predetermined airflow rate, the passage length .[.further.]. being long enough such that such minimum cross section is large enough that the flow of air and water vapor in the passage is essentially laminar.   
     
     
       3. .Iadd.In an .Iaddend..[.Apparatus.]. .Iadd.apparatus.Iaddend.pparatus according to claim 1 wherein the cap is circular and the .[.long, narrow.]. passage follows the curvature of the cap. 
     
     
       4. .Iadd.In an .Iaddend..[.Apparatus.]. .Iadd.apparatus.Iaddend.according to claim 3 wherein said .[.long, narrow.]. passage further includes at least one elbow wherein the passage doubles back on itself. 
     
     
       5. .Iadd.In an .Iaddend..[.Apparatus.]. .Iadd.apparatus.Iaddend.according to claim 2 wherein the cap is circular and the .[.long, narrow.]. groove follows the curvature of the cap. 
     
     
       6. .Iadd.In an .Iaddend..[.Apparatus.]. .Iadd.apparatus.Iaddend.according to claim .[.3.]. .Iadd.2 .Iaddend.wherein said .[.long, narrow.]. groove further includes at least one elbow wherein the passage doubles back on itself. 
     
     
       7. .Iadd.In an .Iaddend..[.Apparatus.]. .Iadd.apparatus.Iaddend.for communicating air between the interior and exterior of a sealed disk drive housing while reducing communication of water vapor between the interior and exterior of said disk drive housing.Iadd., said disk drive housing having a disk drive mounted in the interior thereof, the improvement .Iaddend.comprising: .[.a sealed disk drive housing having an interior and an exterior;.].   .[.a disk drive mounted in the interior of said housing;.].   a vent outlet mounted on said sealed disk drive housing and having at least one passageway communicating between the interior and exterior of said sealed disk drive housing;   .[.a.]. sealing means mounted on said vent outlet and enclosing the passageway;   a vent cap having ridges forming a .[.long, narrow.]. groove between an inlet opening and an outlet opening, the cap mounted on said vent outlet with said ridges pressed against said sealing means and forming an airtight seal therewith such that the groove provides a communicating passage between the vent passageway and the exterior of the housing, the length and cross section of the groove being arranged to provide air-pressure equalization and reduced water vapor communication between the interior and exterior of the housing, the passage .[.generally tracking the circumference of the cap and.]. having a length at least equal to the circumference of the cap and a cross section minimum determined by the length of the passage and a predetermined minimum pressure differential between the interior and exterior of the disk drive housing at a predetermined airflow rate, the passage length further being long enough such that such minimum cross section is large enough that the flow of air and water vapor in the passage is essentially laminar.   
     
     
       8. .Iadd.In an .Iaddend..[.Apparatus.]. .Iadd.apparatus.Iaddend.according to claim 7 wherein the sealing means comprises double-sided adhesive tape. 
     
     
       9. .Iadd.In an .Iaddend..[.Apparatus.]. .Iadd.apparatus.Iaddend.according to claim 7 .Iadd.the improvement .Iaddend.further .[.including.]. .Iadd.comprising.Iaddend.: a central boss mounted on said cap;   an O-ring mounted about said boss; and   a filter captured at an inner portion between the O-ring and the cap.   
     
     
       10. .Iadd.In an .Iaddend..[.Apparatus.]. .Iadd.apparatus.Iaddend.according to claim 8 .Iadd.the improvement .Iaddend.further .[.including.]. .Iadd.comprising.Iaddend.: a central boss mounted on said cap;   an O-ring mounted about said boss; and   a filter captured at an inner portion between the O-ring and the cap and at an outer portion between said double-sided adhesive tape and said disk drive.   
     
     
       11. .Iadd.In an .Iaddend..[.Apparatus.]. .Iadd.apparatus.Iaddend.according to claim 7 wherein the cap is circular and the .[.long, narrow.]. groove follows the curvature of the cap. 
     
     
       12. .Iadd.In an .Iaddend..[.Apparatus.]. .Iadd.apparatus.Iaddend.according to claim 11 wherein said .[.long, narrow.]. groove further includes at least one elbow wherein the passage doubles back on itself. .Iadd.13. In an apparatus for communicating air between the interior and exterior of a sealed disk drive housing while reducing communication of water vapor between the interior and exterior of the disk drive housing, said disk drive housing having a disk drive mounted in the interior thereof, the improvement comprising: vent means mounted on the sealed disk drive housing for providing communication between the interior and exterior of the sealed disk drive housing; and   air passage means for equalizing air-pressure between the interior and exterior of the sealed disk drive housing and for reducing water vapor communication between the interior and exterior thereof, the air passage means comprising a passage communicating between the exterior of the sealed disk drive housing and the vent means, the passage having a cross section minimum determined by the length of the passage and a predetermined minimum pressure differential between the interior and exterior of the sealed disk drive housing at a predetermined airflow rate, the passage length and cross section determined to effect essentially laminar flow of air and water vapor therethrough. .Iaddend. .Iadd.14. In an apparatus according to claim 13 wherein the vent means comprises:   a vent outlet mounted on the sealed disk drive housing;   a vent cap; and   wherein the passage of the air passage means comprises a groove extending between an inlet opening and an outlet opening, the vent cap mounted on the vent outlet such that the passage is formed therebetween. .Iaddend. .Iadd.15. In an apparatus of claim 14 the improvement comprising:   gasket means disposed between the sealed disk drive housing and the vent cap so as to be disposed adjacent the ridges of the air passage means. .Iaddend. .Iadd.16. In an apparatus of claim 15 wherein the vent cap is circular and wherein the passage of the air passage means follows the curvature of the cap. .Iaddend. .Iadd.17. In an apparatus of claim 16 wherein the passage includes at least one elbow wherein said passage doubles back on itself. .Iaddend. .Iadd.18. In an apparatus of claim 13 wherein the vent means further comprises:   filter means for filtering air communicated to the interior of the sealed disk drive housing. .Iaddend. .Iadd.19. In a disk drive apparatus in which air is communicated between the interior and the exterior of a sealed disk drive housing having a disk drive mounted therein, improvement comprising:   vent means for providing air communication between the interior and exterior of the sealed disk drive housing; and   air passage means communicating with the vent means for equalizing air-pressure between the interior and exterior of the sealed disk drive housing and for reducing water vapor communication between the interior and exterior thereof, the air passage means comprising a passage communicating between the exterior of the sealed disk drive housing and the vent means, the passage having a cross section minimum determined by the length thereof so that a predetermined minimum pressure differential is established between the interior and exterior of the sealed disk drive housing at a predetermined airflow rate, the length and cross section of the passage determined to effect laminar air and water vapor flow therethrough. .Iaddend. .Iadd.20. In a disk drive according to claim 19 wherein the vent means comprises:   a vent outlet supported by the sealed disk drive housing;   a vent cap; and wherein the passage of the air passage means comprises a groove formed between the vent cap and the sealed disk drive housing and which extends between an inlet opening and an outlet opening. .Iaddend. .Iadd.21. In a disk drive apparatus of claim 20 the improvement further comprising:     gasket means disposed between the sealed disk drive housing and the vent cap ridges for forming an airtight seal. .Iaddend. .Iadd.22. In a disk drive apparatus of claim 21 wherein the vent cap is circular, and wherein   
     
     
        the passage follows the curvature of the cap. .Iaddend. .Iadd.23.  In a disk drive apparatus of claim 22 wherein the passage includes at least one 
     
     
        elbow wherein said passage doubles back on itself. .Iaddend. .Iadd.24.  In a disk drive apparatus of claim 23 wherein the improvement further comprises: filter means for filtering air communicated to the interior of the sealed disk drive housing. .Iaddend.