US4157967A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Blood filter
Assignee: Baxter International Inc
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Filing: 1977-07-19
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Granted: 1979-06-12
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Expires: 1997-07-19
Abstract
Abstract A filter for blood and the like including a housing defining an inlet for fluids to be filtered, and an outlet for filtered fluid, plus a stack of filter pads of thermoplastic fibers positioned within the housing. According to one aspect of this invention, the stack of pads is joined together at their periphery by a heat seal to form an integral filter unit, while, typically, the stack is joined to the housing at such periphery by a second seal. In another aspect of this invention, the fluid inlet is positioned adjacent a first pad of the stack and the fluid outlet is adjacent a last pad of the stack, the diameter of the fibers of the last pad being smaller than the diameter of the fibers of the first pad, typically with the fiber diameter of intermediate pads generally decreasing from pad to pad in the direction of the last pad.
Inventors
- 👤 Richard P. Meyst
- 👤 Ronald M. Porten
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 08:24
CPC Classifications
B; B29; B29C; B29C66/00; B29C66/01; B29C66/05; B29C66/302; B29C66/3022; A; A61; A61M; A61M5/00; A61M5/14; A61M5/165; B29C65/00; B29C65/02; B29C65/08; B29C66/10; B29C66/13; B29C66/131; B29C66/1312; B29C66/20; B29C66/23; B29C66/232; B29C66/50; B29C66/51; B29C66/54; B29C66/541; B29C66/5412; B29C66/70; B29C66/71; B29C66/72; B29C66/723; B29C66/73; B29C66/739; B29C66/7392; B29C66/73921; B29C66/80; B29C66/83; B29C66/832; B29C66/8322; B29L; B29L2031/00; B29L2031/14; B29L2031/753
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
141 words
In a filter for blood and the like including a housing defining an inlet for fluids to be filtered, an outlet for filtered fluid, and a stack of filter pads of thermoplastic fibers positioned within said housing, the improvement comprising, in combination: said stack of pads being joined together at their periphery by a heat seal to form an integral filter unit, said filter unit being carried in said housing by a separate, second seal between the periphery of said integral filter unit and the housing, the inlet of said housing being carried by a housing wall which defines means for compressing said stack of filter pads whereby the shape of the substantially entire inlet-facing surface of said stack of filter pads defines a continuous convex, curved surface with said inlet being positioned adjacent a central area of said convex surface.
Claim 2
Dependent Claim
141 words
In a filter for blood and the like including a housing defining an inlet for fluids to be filtered, an outlet for filtered fluid, and a stack of filter pads of thermoplastic fibers positioned within said housing, the improvement comprising, in combination: said stack of pads being joined together at their periphery by a heat seal to form an integral filter unit, said filter unit being carried in said housing by a separate, second seal between the periphery of said integral filter unit and the housing, the inlet of said housing being carried by a housing wall which defines means for compressing said stack of filter pads whereby the shape of the substantially entire inlet-facing surface of said stack of filter pads defines a continuous convex, curved surface with said inlet being positioned adjacent a central area of said convex surface.
Claim 3
Dependent Claim
50 words
The filter of claim 1 in which the inlet is adjacent a first pad of said stack and said outlet is adjacent a last pad of said stack, the average diameter of the fibers of said last pad being smaller than the diameter of the fibers of said first pad.
Claim 4
Dependent Claim
57 words
The filter of claim 2 in which the average diameter of the fibers of each pad in said stack is at least as great as the fiber diameter of the immediately adjacent pad in the direction of said last pad, said average fiber diameter generally decreasing from pad to pad in the direction of said last pad.
Claim 5
Dependent Claim
30 words
The filter of claim 3 in which the fraction of the pad volume occupied by said fibers in the last pad is greater than said fraction in the first pad.
Claim 6
Dependent Claim
30 words
The filter of claim 4 in which the fraction of the pad volume occupied by said fibers generally increases from pad to pad in the direction of said last pad.
Claim 7
Dependent Claim
19 words
The filter of claim 5 in which most of the fibers of said stack of filter pads are nonwoven.
Claim 8
Dependent Claim
78 words
The filter of claim 6 in which said first pad exhibits a fiber denier of 14 to 16 and a weight of 9 to 11 ounces per square yard, and said last pad exhibits a fiber denier of essentially 1.5 to 4 and a weight of 10 to 14 ounces per square yard; and intermediate pads, positioned between said first and last pads, having fiber deniers which fall between the fiber deniers of said first and last pads.
Claim 9
Dependent Claim
17 words
The filter of claim 7 in which said filters of the pads consist essentially of polyester fibers.
Claim 10
Dependent Claim
14 words
The filter of claim 8 in which said stack includes essentially five different pads.
Claim 11
Dependent Claim
55 words
The filter of claim 6 in which a binder material is applied to both sides of said first pad, the amount of binder material present on the side of said first pad adjacent said inlet being greater than the amount of binder material present on the side of said first pad opposite to said inlet.
Claim 12
Dependent Claim
176 words
In a filter pad for blood and the like including a housing defining an inlet for fluids to be filtered, an outlet for filtered fluid, and a stack of filter pads positioned within said housing, in which said inlet is adjacent a first pad of said stack and said outlet is adjacent a last pad of said stack, the improvement comprising, in combination: the fiber constitution of each pad being relatively homogeneous throughout said pad, the average diameter of the fibers of each pad being at least as great as the fiber diameter of the immediately adjacent pad in the direction of said last pad, said fiber diameter generally decreasing from pad to pad in the direction of said last pad, the inlet of said housing being carried by a housing wall which defines means for compressing said stack of filter pads whereby the shape of the substantially entire inlet-facing surface of said stack of filter pads defines a continuous convex, curved surface with said inlet being positioned adjacent a central area of said convex surface.
Claim 13
Dependent Claim
176 words
In a filter pad for blood and the like including a housing defining an inlet for fluids to be filtered, an outlet for filtered fluid, and a stack of filter pads positioned within said housing, in which said inlet is adjacent a first pad of said stack and said outlet is adjacent a last pad of said stack, the improvement comprising, in combination: the fiber constitution of each pad being relatively homogeneous throughout said pad, the average diameter of the fibers of each pad being at least as great as the fiber diameter of the immediately adjacent pad in the direction of said last pad, said fiber diameter generally decreasing from pad to pad in the direction of said last pad, the inlet of said housing being carried by a housing wall which defines means for compressing said stack of filter pads whereby the shape of the substantially entire inlet-facing surface of said stack of filter pads defines a continuous convex, curved surface with said inlet being positioned adjacent a central area of said convex surface.
Claim 14
Dependent Claim
30 words
The filter of claim 11 in which the fraction of the pad volume occupied by said fibers in the last pad is greater than said fraction in the first pad.
Claim 15
Dependent Claim
30 words
The filter of claim 12 in which the fraction of the pad volume occupied by said fibers generally increases from pad to pad in the direction of said last pad.
Claim 16
Dependent Claim
19 words
The filter of claim 13 in which most of the fibers of said stack of filter pads are nonwoven.
Claim 17
Dependent Claim
75 words
The filter of claim 14 in which the first pad of said stack is coated with a binder material on both sides thereof, the side of said first pad which is adjacent said inlet carrying a larger amount of binder material than the side of said first pad which is opposite to said inlet, and said stack of filter pads is compressed in said housing, whereby a compression gradient is provided in said first pad.
Claim 18
Dependent Claim
78 words
The filter of claim 15 in which said first pad exhibits a fiber denier of 14 to 16, and a weight of 9 to 11 ounces per square yard, and said last pad exhibits a fiber denier of essentially 1.5 to 4 and a weight of 10 to 14 ounces per square yard; and intermediate pads, positioned between said first and last pads, having fiber deniers which fall between the fiber deniers of said first and last pad.
Claim 19
Dependent Claim
17 words
The filter of claim 16 in which said fibers of the pads consist essentially of polyester fibers.
Claim 20
Dependent Claim
14 words
The filter of claim 17 in which said stack includes essentially five different pads.
Claim 21
Dependent Claim
150 words
In a filter for blood and the like including a housing defining an inlet for fluids to be filtered, an outlet for filtered fluid, and a stack of fiber-containing filter pads positioned within said housing, the improvement comprising, in combination: said stack of pads being joined together at their periphery by a solid seal to define at said periphery a nonporous, gasket-like structure retaining said pads together as an integral filter unit, said filter unit being joined to said housing at said periphery by a second seal between said housing and said gasket-like structure, the inlet of said housing being carried by a housing wall which defines means for compressing said stack of filter pads whereby the shape of the substantially entire inlet-facing surface of said stack of filter pads defines a continuous convex, curved surface with said inlet being positioned adjacent to a central area of said convex surface.
Claim 22
Dependent Claim
150 words
In a filter for blood and the like including a housing defining an inlet for fluids to be filtered, an outlet for filtered fluid, and a stack of fiber-containing filter pads positioned within said housing, the improvement comprising, in combination: said stack of pads being joined together at their periphery by a solid seal to define at said periphery a nonporous, gasket-like structure retaining said pads together as an integral filter unit, said filter unit being joined to said housing at said periphery by a second seal between said housing and said gasket-like structure, the inlet of said housing being carried by a housing wall which defines means for compressing said stack of filter pads whereby the shape of the substantially entire inlet-facing surface of said stack of filter pads defines a continuous convex, curved surface with said inlet being positioned adjacent to a central area of said convex surface.
Claim 23
Dependent Claim
50 words
The filter of claim 19 in which the inlet is adjacent a first pad of said stack and said outlet is adjacent the last pad of said stack, the average diameter of fibers of said last pad being smaller than the average diameter of the fibers of said first pad.
Claim 24
Dependent Claim
84 words
The filter of claim 20 in which the inlet is adjacent a first pad of said stack, both sides of said first pad being coated with a binder material, the amount of said binder material on the side of said first pad adjacent said inlet being greater than the amount of binder material on the side of said first pad opposite to said inlet, said stack of filter pads being compressed in said housing, whereby a compression gradient is provided through said first pad.
Claim 25
Dependent Claim
27 words
The filter of claim 21 in which essentially five times as much binder material is placed on the side of the first pad opposite to said inlet.
Claim 26
Dependent Claim
113 words
In a filter including a housing defining an inlet for fluids to be filtered, an outlet for filtered fluid, and a fiber-containing filter pad positioned within said housing, said filter pad being treated with a binder material to provide increased stiffness to the filter pad, the improvement comprising, in combination: the side of said filter pad facing said inlet carrying a quantity of binder material more than that of the side of said filter pad facing said outlet, said quantity being sufficient that said filter pad being compressed in the housing defines a density gradiant across its width with the outlet-facing side of said filter pad being compressed more than said inlet-facing side.
Claim 27
Dependent Claim
113 words
In a filter including a housing defining an inlet for fluids to be filtered, an outlet for filtered fluid, and a fiber-containing filter pad positioned within said housing, said filter pad being treated with a binder material to provide increased stiffness to the filter pad, the improvement comprising, in combination: the side of said filter pad facing said inlet carrying a quantity of binder material more than that of the side of said filter pad facing said outlet, said quantity being sufficient that said filter pad being compressed in the housing defines a density gradiant across its width with the outlet-facing side of said filter pad being compressed more than said inlet-facing side.
Claim 28
Dependent Claim
38 words
The filter of claim 23 in which approximately five times as much binder is present on the inlet-facing side of said filter pad compared with the amount of binder present on the outlet-facing side of said filter pad.
Claim 29
Dependent Claim
132 words
In a filter device comprising first and second housing members, and a filter pad initially having generally flat, parallel, first and second surfaces, each of said housing members further comprising fluid duct means, and filter pad compression means, the surfaces of said filter pad being impregnated with binder, said first surface of the filter pad being impregnated with a higher concentration of binder than the second surface thereof, said higher concentration being sufficient, to render said first surface sufficiently more rigid than said second surface, said filter pad compression means cooperatively functioning to compress said filter pad therebetween in such a manner as to compress said second surface to a greater extent than said first surface, so as to provide an increasing density gradient from said first surface to said second surface.
Claim 30
Dependent Claim
132 words
In a filter device comprising first and second housing members, and a filter pad initially having generally flat, parallel, first and second surfaces, each of said housing members further comprising fluid duct means, and filter pad compression means, the surfaces of said filter pad being impregnated with binder, said first surface of the filter pad being impregnated with a higher concentration of binder than the second surface thereof, said higher concentration being sufficient, to render said first surface sufficiently more rigid than said second surface, said filter pad compression means cooperatively functioning to compress said filter pad therebetween in such a manner as to compress said second surface to a greater extent than said first surface, so as to provide an increasing density gradient from said first surface to said second surface.
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) | 1982-06-11 | 1982-12-11 | 1983-06-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-06-11 | 1986-12-11 | 1987-06-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-06-11 | 1990-12-11 | 1991-06-12 | $7700.00 | Window Closed / Lapsed |