US4965032A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Filter device with non-bypass edge seal
Assignee: Pall Corp
•
Filing: 1989-09-15
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Granted: 1990-10-23
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Expires: 2009-09-15
Abstract
Abstract A process for making filters with a non-bypassing peripheral seal which comprises heating a cylindrical filter housing to expand its internal diameter; inserting a filter disc that has a diameter larger than that of the internal diameter of the housing when cold; and allowing the assembly to cool.
Inventors
- 👤 David B. Pall
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 08:32
CPC Classifications
B; B29; B29C; B29C63/00; B29C63/38; B29C63/42; B01; B01D; B01D27/00; B01D27/08; B01D29/00; B01D29/01; B01D29/012; B29C65/00; B29C65/66; B29C65/665; B29D; B29D99/00; B29D99/005; B29C66/00; B29C66/70; B29C66/71; B29L; B29L2031/00; B29L2031/14; B29L2031/755; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49826; Y10T29/49863; Y10T29/49865
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
160 words
A process for the production of a filter unit, said filter unit comprising at least one nonwoven fibrous filter disc element in a tight fit with the interior wall of a cylindrical filter housing made from a material with a positive coefficient of expansion at temperatures from about 0° to about 100° C. of at least about 3×10 -5 /°C., comprising: (a) compressing a sheet of a non-woven fibrous material while in a heat softened state to a desired density; (b) cutting a filter element disc from such compressed sheet with a diameter from about 0.2 to about 1% greater than the interior diameter of the filter housing at ambient temperature; (c) heating the housing to an elevated temperature at which its interior diameter exceeds the diameter of the disc at ambient temperature; (d) inserting the filter element disc into the housing while maintaining the housing at the elevated temperature; and (e) allowing the assembly to cool to ambient temperature.
Claim 2
Dependent Claim
160 words
A process for the production of a filter unit, said filter unit comprising at least one nonwoven fibrous filter disc element in a tight fit with the interior wall of a cylindrical filter housing made from a material with a positive coefficient of expansion at temperatures from about 0° to about 100° C. of at least about 3×10 -5 /°C., comprising: (a) compressing a sheet of a non-woven fibrous material while in a heat softened state to a desired density; (b) cutting a filter element disc from such compressed sheet with a diameter from about 0.2 to about 1% greater than the interior diameter of the filter housing at ambient temperature; (c) heating the housing to an elevated temperature at which its interior diameter exceeds the diameter of the disc at ambient temperature; (d) inserting the filter element disc into the housing while maintaining the housing at the elevated temperature; and (e) allowing the assembly to cool to ambient temperature.
Claim 3
Dependent Claim
27 words
The process according to claim 1 in which the interior diameter of the heated housing is within about 2% of the ambient temperature diameter of the disc.
Claim 4
Dependent Claim
30 words
The process according to claim 1 in which the disc is cut from laminated sheet compressed to a voids volume in the range of from about 65% to about 85%.
Claim 5
Dependent Claim
17 words
The process according to claim 1 in which the filter disc is made from polybutylene terephthalate fibers.
Claim 6
Dependent Claim
31 words
The process according to claim 1 in which a plurality of discs with differing porosities are inserted into the housing in increasing order of porosity from the bottom to the top.
Claim 7
Dependent Claim
23 words
The process according to claim 1 in which the disc is a preformed filter element comprising a plurality of layers with differing porosities.
Claim 8
Dependent Claim
24 words
The process according to claim 1 in which the disc is at or below ambient temperature when it is inserted into the heated housing.
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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) | 1993-10-22 | 1994-04-23 | 1994-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-10-22 | 1998-04-23 | 1998-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-10-22 | 2002-04-23 | 2002-10-23 | $7700.00 | Window Closed / Lapsed |