Patent US4062773A successfully refreshed from Google Patents.
US4062773A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High surface to volume structure and method of generating same
Assignee: Baxter International Inc
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Filing: 1975-09-02
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Granted: 1977-12-13
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Expires: 1995-09-02
Abstract
Abstract A filter assembly and element are disclosed herein for use in filtering biological fluids. The assembly includes a variable volume housing within which is positioned a cylindrically-shaped, high surface area filter. During operation, the housing volume is changed, but the surface area available for filtration remains substantially constant. This permits the filter to be operated with low priming volumes and also to effectively reduce gas bubble entrapment in the filter. A method of making the element and a method for operating the filter assembly are also disclosed.
Inventors
- 👤 Ronald J. Leonard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 20:57
CPC Classifications
A; A61; A61M; A61M1/00; A61M1/36; A61M1/3621; A61M1/3627; B; B01; B01D; B01D29/00; B01D29/11; B01D29/111; B01D29/13; B01D29/15; B01D29/21; B01D29/213
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
111 words
A filter assembly for use in filtering biological fluids which comprises: an expandable and contractible bellows-configurated housing having a fluid inlet and a fluid outlet; a cylindrically-shaped, high surface area filter element positioned within and cooperatively associated with said housing to filter fluid flowing through said housing between said inlet and said outlet, said filter including an elongated sleeve of filter material and a coil-shaped spring positioned within and engaging said sleeve for shaping said sleeve so as to provide a high surface area for filtration, said filter element being constructed and arranged so that the surface area for filtration remains substantially unchanged as the volume of the housing is changed.
Claim 2
Dependent Claim
111 words
A filter assembly for use in filtering biological fluids which comprises: an expandable and contractible bellows-configurated housing having a fluid inlet and a fluid outlet; a cylindrically-shaped, high surface area filter element positioned within and cooperatively associated with said housing to filter fluid flowing through said housing between said inlet and said outlet, said filter including an elongated sleeve of filter material and a coil-shaped spring positioned within and engaging said sleeve for shaping said sleeve so as to provide a high surface area for filtration, said filter element being constructed and arranged so that the surface area for filtration remains substantially unchanged as the volume of the housing is changed.
Claim 3
Dependent Claim
58 words
A filter assembly as in claim 1, wherein: said filter element is centrally positioned within said housing and an annular chamber is defined by the space between the filter element and the housing; said inlet is positioned to direct unfiltered fluid into said chamber; and said outlet is positioned to receive filtered fluid flow from said filter element.
Claim 4
Dependent Claim
39 words
A filter assembly as in claim 2, wherein said housing includes end walls substantially parallel to each other so that the volume of said housing may be varied by moving said end walls toward and away from each other.
Claim 5
Dependent Claim
59 words
A filter assembly as in claim 3, wherein said filter element is positioned within said housing, such that one end of the filter element engages one of said end walls and the other engages the other end wall so that said filter element is compressed and expanded as said end walls are moved toward and away from each other.
Claim 6
Dependent Claim
17 words
A filter assembly as in claim 4, wherein said inlet extends through one of said end walls.
Claim 7
Dependent Claim
112 words
A filter assembly for use in filtering biological fluids which comprises: a variable volume housing having: first end wall means; second end wall means; expandable sidewall means, which is adapted to expand and contract upon movement of the end walls toward and away from each other so as to vary the volume of the housing; an inlet; and an outlet; and a high surface area filter element positioned within and cooperatively associated with said housing to filter fluid flowing through said housing between said inlet and said outlet, said filter element constructed and arranged so that said surface area for filtration remains substantially unchanged as the volume of the housing is changed.
Claim 8
Dependent Claim
112 words
A filter assembly for use in filtering biological fluids which comprises: a variable volume housing having: first end wall means; second end wall means; expandable sidewall means, which is adapted to expand and contract upon movement of the end walls toward and away from each other so as to vary the volume of the housing; an inlet; and an outlet; and a high surface area filter element positioned within and cooperatively associated with said housing to filter fluid flowing through said housing between said inlet and said outlet, said filter element constructed and arranged so that said surface area for filtration remains substantially unchanged as the volume of the housing is changed.
Claim 9
Dependent Claim
82 words
A filter assembly as in claim 6, wherein said filter element is cylindrically shaped and includes: a sleeve of filter material; and a coil spring positioned within and engaging said sleeve for shaping said sleeve to provide said filtration surface area, with one end of said filter element engaging said first end wall and the other end engaging said second wall so that said filter element is compressed and expanded as said end walls are moved toward and away from each other.
Claim 10
Dependent Claim
59 words
A filter assembly as in claim 6, wherein said filter element is centrally positioned within said housing and an annular chamber is defined by the space between the filter element and the housing; said inlet is positioned to direct unfiltered fluid into said annular chamber; and said outlet is positioned to receive filtered fluid flow from said filter element.
Claim 11
Dependent Claim
17 words
A filter assembly as in claim 8, wherein said inlet extends through one of said end walls.
Claim 12
Dependent Claim
14 words
A filter assembly as in claim 6, wherein said housing sidewalls are bellows shaped.
Claim 13
Independent Claim
117 words
A method for filtering biological fluids in a filter assembly having a variable volume housing with an inlet and an outlet and a filter element having a high surface area, cooperatively associated with said housing and positioned therein to filter fluid flowing between said inlet and said outlet, said filter constructed so that said surface area remains substantially constant as the volume of the housing is changed, said method of filtration including the steps of: expanding said housing; flowing fluid through said housing through said inlet and outlet so as to fill said housing with fluid; pumping said housing so as to remove entrapped gas bubbles; and maintaining said housing in the compressed position during normal operation.
Claim 14
Independent Claim
117 words
A method for filtering biological fluids in a filter assembly having a variable volume housing with an inlet and an outlet and a filter element having a high surface area, cooperatively associated with said housing and positioned therein to filter fluid flowing between said inlet and said outlet, said filter constructed so that said surface area remains substantially constant as the volume of the housing is changed, said method of filtration including the steps of: expanding said housing; flowing fluid through said housing through said inlet and outlet so as to fill said housing with fluid; pumping said housing so as to remove entrapped gas bubbles; and maintaining said housing in the compressed position during normal operation.
Claim 15
Dependent Claim
92 words
A filter element for use in filtering biological fluids which comprises: a sleeve of filter material which includes an outer filter layer and an inner support layer bonded to said outer layer; coil spring means positioned within and engaging said sleeve for shaping said sleeve so as to provide a high surface area for filtration whether said spring is expanded or compressed; said inner support layer being bonded to said shape-sustaining spring; and said spring having a coating of polyethylene or polypropylene for cooperation in bonding said spring to said inner layer.
Claim 16
Dependent Claim
92 words
A filter element for use in filtering biological fluids which comprises: a sleeve of filter material which includes an outer filter layer and an inner support layer bonded to said outer layer; coil spring means positioned within and engaging said sleeve for shaping said sleeve so as to provide a high surface area for filtration whether said spring is expanded or compressed; said inner support layer being bonded to said shape-sustaining spring; and said spring having a coating of polyethylene or polypropylene for cooperation in bonding said spring to said inner layer.
Claim 17
Dependent Claim
44 words
A filter element as in claim 12, wherein said outer filter layer is a nylon mesh having openings therein of about 20-40 microns and said inner layer is of polyethylene or polypropylene and has openings therein greater than the openings in said mesh layer.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-12-12 | 1981-06-13 | 1981-12-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-12-12 | 1985-06-13 | 1985-12-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-12-12 | 1989-06-13 | 1989-12-13 | $7700.00 | Window Closed / Lapsed |