Surgery – Respiratory method or device – Means for removing substance from respiratory gas
Reexamination Certificate
2002-08-27
2004-05-18
Lo, Weilun (Department: 3761)
Surgery
Respiratory method or device
Means for removing substance from respiratory gas
C128S206160, C128S206170
Reexamination Certificate
active
06736138
ABSTRACT:
FIELD
The present invention is in the field of fluid-purifying filters. In particular it teaches a seamless pad-type fluid purifying filter and a method for its manufacture.
BACKGROUND
The prior art teaches a variety of structures of pad-type filters and methods for their manufacture. Examples of such teachings are disclosed in U.S. Pat. Nos. Re: 35,062 (a 1995 reissue of U.S. Pat. No. 4,886,058, issued on Dec. 12, 1989), 6,345,620 and 5,992,414, all of which are incorporated in this application by reference. In addition, U.S. Pat. No. 6,309,438 which teaches a “filter unit and dust-proof mask therewith” and discloses highly efficient filtration media, such as biaxially expanded polytetrafluoroethylene porous films, is also incorporated in this application by reference.
In accordance with the present invention, a pad-type filter is defined as a filter comprising at least two layers of filtration media hermetically sealed to one another along a common perimeter and separated from one another by an inner chamber created therebetween and at least one opening in at least one of the layers such that a fluid passing through said opening passes only through at least one of the two layers. A pad-type filter thus offers a larger surface area for fluid flow than the projected area of the filter and, therefore, exhibits a lower overall resistance to flow at the same volume flow rate through the same filtration media than single layer filters having the same projected area. A significant disadvantage, however, of all pad-type filters of the prior art is that the sealed area adjacent to and around the common perimeter is highly compacted and inefficiently, if at all, utilized. Thus, such pad-type filters still suffer severe limitations on their filtration efficiency, resistance to flow and filtration material utilization efficiency. The seamless pad-type filter of the present invention overcomes the problems associated with prior art pad-type filters. In addition, the present invention provides, at more efficient material utilization and lower material and assembly costs, a method for manufacture of seamless pad-type filters. The pad-type filter of the present invention is characterized in that it eliminates the need for having to make a seal between the two sides of the filter along their common perimeter, as necessitated in the prior art.
REFERENCES:
patent: 4886058 (1989-12-01), Brostrom et al.
patent: 5035236 (1991-07-01), Kanegaonkar
patent: 5240479 (1993-08-01), Bachinski
patent: 6161540 (2000-12-01), Fecteau
patent: 6309438 (2001-10-01), Kanno et al.
patent: 6345620 (2002-02-01), Salapow et al.
Lo Weilun
Mendoza Michael
LandOfFree
Seamless pad-type filter does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Seamless pad-type filter, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Seamless pad-type filter will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3241077