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US4983288A
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Filter element with membrane-type filter material
Assignee: SEITZ FILTER-WERKE und Co GmbH
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Filing: 1989-06-02
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Granted: 1991-01-08
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Expires: 2009-06-02
Abstract
Abstract A filter element for a filter cartridge has an upstream or prefiltering membrane with frustoconical pores converging in the direction of liquid flow through the filter element and a final filtering membrane at the downstream side with cylindrical pores smaller than the smallest diameter of the frustoconical pores.
Inventors
- 👤 Massoud Karbachsch
- 👤 Manfred Pett
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 15:42
CPC Classifications
B; B01; B01D; B01D69/00; B01D69/12
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
112 words
A filter element, comprising: a support structure; means on said support structure for guiding a flow of a fluid through said support structure from an upstream side to a downstream side; a prefiltering membrane on said upstream side of said support structure, traversed by said fluid and forming an asymmetric pore structure with pores converging in a flow direction from said upstream side to said downstream side; and a final filtering membrane on said downstream side of said support structure, of a chemical composition different from that of said prefiltering membrane, traversed by said fluid in said direction and formed with pores of generally uniform cross section forming a symmetric pore structure.
Claim 2
Dependent Claim
112 words
A filter element, comprising: a support structure; means on said support structure for guiding a flow of a fluid through said support structure from an upstream side to a downstream side; a prefiltering membrane on said upstream side of said support structure, traversed by said fluid and forming an asymmetric pore structure with pores converging in a flow direction from said upstream side to said downstream side; and a final filtering membrane on said downstream side of said support structure, of a chemical composition different from that of said prefiltering membrane, traversed by said fluid in said direction and formed with pores of generally uniform cross section forming a symmetric pore structure.
Claim 3
Dependent Claim
18 words
The filter element defined in claim 1 wherein said support structure and said membranes form a cartridge filter.
Claim 4
Dependent Claim
32 words
The filter element defined in claim 2 wherein said pores of said prefiltering membrane have smallest diameters x2 which are larger than diameters y of the pores of said final filtering membrane.
Claim 5
Dependent Claim
53 words
The filter element defined in claim 3 wherein said smallest diameters x2 are in a range of 0.8 micrometer to 3 micrometers and the diameters of the pores of said prefiltering membrane increase from said smallest diameters in a direction opposite to said flow direction by a factor of two to four times.
Claim 6
Dependent Claim
18 words
The filter element defined in claim 2 wherein said diameters y range from 0.1 micrometer to 0.65 micrometer.
Claim 7
Dependent Claim
41 words
The filter element defined in claim 2 wherein said prefiltering membrane is composed of an aromatic polyamide or polysulfone or a cellulose derivative and said final filtering membrane is composed of an aliphatic polyamide or polysulfone or polyvinylidenefluoride, polytetrafluoroethylene or polypropylene.
Claim 8
Dependent Claim
25 words
The filter element defined in claim 6 wherein said final filtering membrane is composed of an aliphatic polyamide and said aliphatic polyamide is nylon 66.
Claim 9
Dependent Claim
28 words
The filter element defined in claim wherein said prefiltering membrane is composed of an aromatic polyamide and said aromatic polyamide is a copolymer of isophthalic acid and m-phenyldiamine.
Claim 10
Dependent Claim
17 words
The filter element defined in claim 2 wherein said prefiltering membrane is formed on a deep-filter layer.
Claim 11
Dependent Claim
16 words
The filter element defined in claim 9 wherein said deep-filter layer is formed from glass fibers.
Claim 12
Dependent Claim
21 words
The filter element defined in claim 9 wherein said deep-filter layer is embedded in a polyamide, polysulfone or a cellulose derivative.
Claim 13
Dependent Claim
20 words
The filter element defined in claim 2 wherein said final filtering membrane is constituted of at least two membrane layers.
Claim 14
Dependent Claim
14 words
The filter element defined in claim 12 wherein said layers are bonded fixedly together.
Claim 15
Dependent Claim
14 words
The filter element defined in claim 12 wherein said layers have different chemical compositions.
Claim 16
Dependent Claim
23 words
The filter element defined in claim 12 wherein said layers are reinforced by a fibrous fleece or textile fabric interposed between said layers.
Claim 17
Dependent Claim
24 words
The filter element defined in claim 12 wherein said fibrous fleece or textile fabric interposed between said layers is composed of polypropylene or polyester.
Claim 18
Dependent Claim
28 words
The filter element defined in claim 2 wherein the chemical compositions of the prefiltering and final filtering membranes are selected so that the membranes have different surface characteristics.
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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) | 1994-01-07 | 1994-07-09 | 1995-01-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-01-07 | 1998-07-09 | 1999-01-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-01-07 | 2002-07-09 | 2003-01-08 | $7700.00 | Window Closed / Lapsed |