Patent US2539803A successfully refreshed from Google Patents.
Patent US5507847A successfully refreshed from Google Patents.
US5507847A
Expired / Lapsed
US
⏱️ 0.0 years remaining
ULPA filter
Assignee: W.L. Gore and Associates Inc
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Filing: 1994-07-29
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Granted: 1996-04-16
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Expires: 2014-07-29
Abstract
Abstract An improved filter unit suitable for use in a variety of clean air filtration applications is taught. The filter unit employs continuous microporous filtration membranes, such as expanded polytetrafluoroethylene, to deliver exceptional filtration efficiencies on the order of 99.99999% at 0.1 mu m with minimal pressure drop produced across the filter. Additionally, the filter unit of the present invention has the further advantage of avoiding many previous deficiencies in HEPA and ULPA filter units, such as filter contamination from shedding particles and/or out-gassing, and limitations on chemicals to which the filter can be exposed without deterioration. As a result, the present invention provides a cleaner and more durable filter that can be used to address growing contamination problems in many different industries, such as electronics and pharmaceuticals.
Inventors
- 👤 Nelson A. George
- 👤 Michael G. Sutsko
- 👤 Douglas B. McKenna
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 10:48
CPC Classifications
B; B32; B32B; B32B27/00; B32B27/06; B32B27/08; B01; B01D; B01D39/00; B01D39/08; B01D39/083; B01D39/14; B01D39/16; B01D39/1692; B01D46/00; B01D46/10; B01D46/52; B01D46/521; B01D71/00; B01D71/06; B01D71/30; B01D71/32; B01D71/36; B32B27/32; B32B27/322; B32B27/38; B32B27/40; B32B7/00; B32B7/04; B32B7/12; B01D2239/00; B01D2239/06; B01D2239/065; B01D2239/0654; B01D2275/00; B01D2275/10; B01D2279/00; B01D2279/50; B01D2279/51; B32B37/00; B32B37/12; B32B37/1207; B32B2037/1215; B32B2305/00; B32B2305/02; B32B2305/026; B32B2327/00; B32B2327/12; B32B2327/18; B32B2363/00; B32B2375/00
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
91 words
A filter for use in air conditioning systems in clean facilities which comprises: a primary filtration layer of microporous polytetrafluoroethylene (PTFE); at least one upstream layer of permeable support material; at least one down stream layer of permeable support material, the filtration layer being loosely sandwiched between the upstream layer and downstream layer of support material; wherein the primary filtration layer and the support materials combine to provide a filtration efficiency of at least 99.97% at 0.3 μm and less than 1 inch water pressure drop at 100 ft/min air velocity.
Claim 2
Dependent Claim
91 words
A filter for use in air conditioning systems in clean facilities which comprises: a primary filtration layer of microporous polytetrafluoroethylene (PTFE); at least one upstream layer of permeable support material; at least one down stream layer of permeable support material, the filtration layer being loosely sandwiched between the upstream layer and downstream layer of support material; wherein the primary filtration layer and the support materials combine to provide a filtration efficiency of at least 99.97% at 0.3 μm and less than 1 inch water pressure drop at 100 ft/min air velocity.
Claim 3
Dependent Claim
32 words
The filter of claim 1 that further comprises a second filtration layer of microporous PTFE mounted in series with the primary filtration layer so as to provide uniform filtration through the filter.
Claim 4
Dependent Claim
26 words
The filter of claim 1 wherein the upstream support material comprises a layer of screen; and the down stream support material comprises a layer of screen.
Claim 5
Dependent Claim
20 words
The filter of claim 3 wherein the upstream support material includes an additional layer of relatively soft, flexible support material.
Claim 6
Dependent Claim
31 words
The filter of claim 4 wherein a second filtration layer of microporous PTFE is mounted in series with the primary filtration layer so as to provide uniform filtration through the filter.
Claim 7
Dependent Claim
15 words
The filter of claim 3 wherein the primary filtration layer and the screens are pleated.
Claim 8
Dependent Claim
19 words
The filter of claim 6 wherein the pleated filtration layer and screens are mounted and sealed in a frame.
Claim 9
Dependent Claim
24 words
The filter of claim 7 wherein the pleated filtration layer and screens are sealed in the frame with a potting material resistant to out-gassing.
Claim 10
Dependent Claim
23 words
The filter of claim 8 wherein the potting material is selected from the group consisting of silicone, polyurethane, epoxy, plastic adhesives, and plastisol.
Claim 11
Dependent Claim
19 words
The filter of claim 1 wherein the filter has a filtration efficiency of at least 99.99% at 0.1 μm.
Claim 12
Dependent Claim
19 words
The filter of claim 1 wherein the filter has a filtration efficiency of at least 99.999% at 0.1 μm.
Claim 13
Dependent Claim
19 words
The filter of claim 10 wherein the filter has a filtration efficiency of at least 99.99999% at 0.1 μm.
Claim 14
Dependent Claim
46 words
The filter of claim 1 which further comprises a second filtration layer of microporous PTFE mounted against the primary filtration layer; wherein the two filtration layers serve to protect one another from damage and avoid leakage through random holes in either one of the filtration layers.
Claim 15
Dependent Claim
100 words
A filter for use in clean facilities for filtering air of contaminates which comprises: a first filtration layer of microporous material; a second filtration layer of microporous material mounted parallel to the first filtration layer; at least one layer of support material mounted upstream of the filtration layers; at least one layer of support material mounted downstream of the filtration layers; wherein the filtration layers and the support material layers are pleated; and wherein the filter has a filtration efficiency of at least 99.999% at 0.1 μm and less than 1 inch water pressure drop at 100 ft/min air velocity.
Claim 16
Dependent Claim
100 words
A filter for use in clean facilities for filtering air of contaminates which comprises: a first filtration layer of microporous material; a second filtration layer of microporous material mounted parallel to the first filtration layer; at least one layer of support material mounted upstream of the filtration layers; at least one layer of support material mounted downstream of the filtration layers; wherein the filtration layers and the support material layers are pleated; and wherein the filter has a filtration efficiency of at least 99.999% at 0.1 μm and less than 1 inch water pressure drop at 100 ft/min air velocity.
Claim 17
Dependent Claim
19 words
The filter of claim 14 wherein an additional layer of support material is mounted upstream of the filtration layers.
Claim 18
Dependent Claim
34 words
The filter of claim 14 wherein the pleated filtration layers and support material are mounted in a frame with an air tight connection between the frame and the pleated filtration layers and support material.
Claim 19
Dependent Claim
26 words
The filter of claim 16 wherein the air tight connection comprises a potting material selected from the group comprising: silicone, hot-melt adhesive, polyurethane, epoxy, or plastisol.
Claim 20
Dependent Claim
34 words
The filter of claim 14 wherein each of the filter layers comprises microporous expanded polytetrafluoroethylene (PTFE) comprising a filtration efficiency of at least 99.99% at 0.1 μm at an airflow velocity of 10.5 ft/min.
Claim 21
Dependent Claim
31 words
The filter of claim 18 wherein each of the filter layers comprises material having a pressure drop of less than 0.5 inches of water at an airflow velocity of 12 ft/min.
Claim 22
Dependent Claim
37 words
The filter of claim 18 wherein each of the filter layers comprises a material with a mean ball burst value of at least 3.0 lb-force within a range of less than 1.4 between maximum and minimum values.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-04-16 | 1999-10-16 | 2000-04-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-04-16 | 2003-10-16 | 2004-04-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-04-16 | 2007-10-16 | 2008-04-16 | $7700.00 | Window Closed / Lapsed |