US4872988A
Expired / Lapsed
US
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Method and device for separation of colloidal suspensions
Assignee: East West Bank
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Filing: 1988-02-02
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Granted: 1989-10-10
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Expires: 2008-02-02
Abstract
Abstract Particulates are separated from colloidal suspensions by filtration where the filter is oscillated relative to the suspension in order to inhibit plugging of the filter. Plugging is substantially eliminated and filtration rates greatly enhanced by oscillating the membrane at a sufficiently high frequency and with a sufficiently large displacement so that the Reynold's number of the relative flow is greater than about 1.
Inventors
- 👤 Joseph B. Culkin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:08
CPC Classifications
B; B01; B01D; B01D63/00; B01D63/16; B01D29/00; B01D29/11; B01D29/117; B01D29/76; B01D29/86; B01D29/865; B01D33/00; B01D33/01; B01D33/03; B01D33/0307; B01D33/033; B01D33/0346; B01D33/15; B01D33/29; B01D65/00; B01D65/08; B01D2321/00; B01D2321/20; B01D2321/2033; B01D2321/2058
Claims Analysis
Total Claims: 38
Claim 1
Independent Claim
79 words
A method for separating particulates from a colloidal suspension in which plugging of a filter membrane is inhibited said method comprising: inhibiting plugging of a membrane from a sample blood suspension, by passing the suspension through the filter membrane, the filter membrane selected to substantially block passage of the particulates; and simultaneously inducing a relative oscillation between the filter membrane and the suspension with a frequency and displacement selected to provide a Reynold's number of at least about 1.
Claim 2
Independent Claim
79 words
A method for separating particulates from a colloidal suspension in which plugging of a filter membrane is inhibited said method comprising: inhibiting plugging of a membrane from a sample blood suspension, by passing the suspension through the filter membrane, the filter membrane selected to substantially block passage of the particulates; and simultaneously inducing a relative oscillation between the filter membrane and the suspension with a frequency and displacement selected to provide a Reynold's number of at least about 1.
Claim 3
Dependent Claim
18 words
A method as in claim 1, wherein the filter membrane is oscillated while the suspension remains substantially static.
Claim 4
Dependent Claim
19 words
A method as in claim 1, wherein the colloidal suspension is oscillated while the filter membrane remains substantially static.
Claim 5
Dependent Claim
28 words
A method as in claim 1, wherein the suspension is passed through the membrane filter by providing a negative pressure on a downstream side of the membrane filter.
Claim 6
Dependent Claim
28 words
A method as in claim 1, wherein the suspension is passed through the membrane filter by providing a positive pressure on an upstream side of the membrane filter.
Claim 7
Dependent Claim
19 words
A method as in claim 1, wherein the frequency is in the range from about 25 to 250 Hz.
Claim 8
Dependent Claim
26 words
A method as in claim 6, wherein the displacement between the filter membrane and the suspension is in the range from about 0.3 to 5 mm.
Claim 9
Independent Claim
99 words
A method for separating plasma from blood samples with a filter membrane, comprising: inhibiting plugging of the filter membrane, by introducing a blood sample into a receptacle having the filter membrane in contact with said blood sample; providing a differential pressure across the membrane to cause the plasma to flow therethrough; simultaneously reciprocating the receptacle in a direction substantially normal to the direction of blood plasma flow through the filter membrane with a frequency and displacement sufficient to disperse a concentration polarization layer at the membrane surface; and collecting the blood plasma as it flows through the filter membrane.
Claim 10
Independent Claim
99 words
A method for separating plasma from blood samples with a filter membrane, comprising: inhibiting plugging of the filter membrane, by introducing a blood sample into a receptacle having the filter membrane in contact with said blood sample; providing a differential pressure across the membrane to cause the plasma to flow therethrough; simultaneously reciprocating the receptacle in a direction substantially normal to the direction of blood plasma flow through the filter membrane with a frequency and displacement sufficient to disperse a concentration polarization layer at the membrane surface; and collecting the blood plasma as it flows through the filter membrane.
Claim 11
Dependent Claim
26 words
A method as in claim 8, wherein the frequency and displacement of the reciprocation are sufficient to provide a Reynold's number of at least about 1.
Claim 12
Dependent Claim
32 words
A method as in claim 8, wherein the receptacle is an open capillary tube and the blood sample is introduced by contacting a tip of the capillary tube with the blood sample.
Claim 13
Dependent Claim
21 words
A method as in claim 10, wherein the blood sample is a drop of blood drawn by lancing a patient's skin.
Claim 14
Dependent Claim
38 words
A method as in claim 10, wherein the filter membrane forms a portion of a wall of the capillary and the differential pressure is provided by drawing a negative pressure in a receiver jacket circumscribing the filter membrane.
Claim 15
Dependent Claim
51 words
A method as in claim 8, wherein the receptacle is an enclosed bag having flexible walls and wherein the filter membrane is mounted within the bag and attached to a receiver having a port external to the bag, said differential pressure being provided by drawing a negative pressure on the port.
Claim 16
Dependent Claim
40 words
A method as in claim 8, wherein the receptacle is defined by a cylindrical membrane filter and is mounted inside a rigid enclosure having a pressure port, said differential pressure being applied by drawing a negative pressure through said port.
Claim 17
Dependent Claim
20 words
A method as in claim 14, wherein the receptacle is rotationally reciprocated about a cylindrical axis of the membrane filter.
Claim 18
Independent Claim
103 words
A system for separating particulates from a colloidal blood suspension in which plugging of a membrane filter by the particulated is inhibited, said system comprising: the filter membrane selected to block passage of the particulates in the suspension; means for passing the colloidal blood suspension through the membrane filter; means for collecting permeate after it has passed through the filter membrane; and means for inhibiting plugging of the membrane by the colloidal blood suspension, including means for inducing relative oscillation between the filter membrane and the suspension with a frequency and displacement sufficient to provide a Reynold's number of at least about 1.
Claim 19
Independent Claim
103 words
A system for separating particulates from a colloidal blood suspension in which plugging of a membrane filter by the particulated is inhibited, said system comprising: the filter membrane selected to block passage of the particulates in the suspension; means for passing the colloidal blood suspension through the membrane filter; means for collecting permeate after it has passed through the filter membrane; and means for inhibiting plugging of the membrane by the colloidal blood suspension, including means for inducing relative oscillation between the filter membrane and the suspension with a frequency and displacement sufficient to provide a Reynold's number of at least about 1.
Claim 20
Dependent Claim
24 words
A system as in claim 16, wherein the filter membrane has a molecular weight cutoff in the range from about 0.1 to 1000 kilodaltons.
Claim 21
Dependent Claim
28 words
A system as in claim 16, wherein the means for passing the colloidal suspension through the membrane filter is a differential pressure generator connected across the filter membrane.
Claim 22
Dependent Claim
23 words
A system as in claim 16, wherein the differential pressure generator applies a negative pressure on a downstream side of the membrane filter.
Claim 23
Dependent Claim
34 words
A system as in claim 19, wherein the means for collecting permeate includes a receiver attached to a downstream side of the filter membrane and wherein said receiver is attached to the negative pressure.
Claim 24
Dependent Claim
23 words
A system as in claim 16, wherein the differential pressure generator applies a positive pressure on an upstream side of the membrane filter.
Claim 25
Dependent Claim
32 words
A system as in claim 16, wherein the means for inducing a relative oscillation includes means for reciprocating the membrane filter in a direction normal to the passage of the permeate therethrough.
Claim 26
Dependent Claim
23 words
A system as in claim 16, further comprising a receptacle for holding the colloidal suspension on an upstream side of the membrane filter.
Claim 27
Dependent Claim
37 words
A system as in claim 23, wherein the means for inducing relative oscillation includes means for applying an oscillatory pressure on the colloidal suspension in the receptacle, whereby the colloidal suspension is reciprocated past the filter membrane.
Claim 28
Dependent Claim
39 words
A system as in claim 16, wherein the means for inducing relative oscillation operates at a frequency in the range from about 25 to 250 Hz and imparts a displacement in the range from about 0.3 to 5 mm.
Claim 29
Dependent Claim
29 words
A system as in claim 25, wherein the means for inducing relative oscillation operates with a frequency and displacement selected to provide a Reynold's number greater than about 10.
Claim 30
Independent Claim
67 words
An apparatus comprising: means for separating particles from a colloidal blood suspension, including: an assembly including a filter membrane having an upstream side and a downstream side, a receiver attached to the downstream side to collect fluid passing through the filter membrane, and means for connecting a differential pressure across the membrane to induce fluid flow thereacross; and means for detachably mounting the assembly on an oscillator.
Claim 31
Independent Claim
67 words
An apparatus comprising: means for separating particles from a colloidal blood suspension, including: an assembly including a filter membrane having an upstream side and a downstream side, a receiver attached to the downstream side to collect fluid passing through the filter membrane, and means for connecting a differential pressure across the membrane to induce fluid flow thereacross; and means for detachably mounting the assembly on an oscillator.
Claim 32
Dependent Claim
25 words
An apparatus as in claim 27, wherein the filter membrane is formed on at least a portion of the inside surface of a capillary tube.
Claim 33
Dependent Claim
17 words
An apparatus as in claim 28, wherein the receiver is a rigid jacket circumscribing the capillary tube.
Claim 34
Dependent Claim
21 words
An apparatus as in claim 29, wherein the means for connecting a differential pressure is a port in the rigid jacket.
Claim 35
Dependent Claim
14 words
An apparatus as in claim 27, wherein the filter membrane is a flat sheet.
Claim 36
Dependent Claim
24 words
An apparatus as in claim 31, wherein the filter membrane includes a pair of sheets sealed over a collection manifold which defines the receiver.
Claim 37
Dependent Claim
23 words
An apparatus as in claim 27, wherein the filter membrane is cylindrical and the receiver is a rigid enclosure circumscribing the filter membrane.
Claim 38
Dependent Claim
15 words
An apparatus as in claim 33, wherein the filter membrane is a hollow porous fiber.
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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) | 1992-10-09 | 1993-04-10 | 1993-10-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-10-09 | 1997-04-10 | 1997-10-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-10-09 | 2001-04-10 | 2001-10-10 | $7700.00 | Window Closed / Lapsed |