Recirculating fluid filtration system

Patent metadata

Field	Value
Publication number	US-9345826-B2
Application number	US-201213619010-A
Country	US
Kind code	B2
Filing date	Sep 14, 2012
Priority date	Sep 15, 2011
Publication date	May 24, 2016
Grant date	May 24, 2016

Abstract

A fluid filtration system comprising a cross-flow filter is arranged to permit a first pump to recirculate part of the retentate of the filter to the inlet of the cross-flow filter and a second pump to return part of the permeate to the inlet of the cross-flow filter. A third pump is configured supply source fluid to the inlet of the filter. The flow path between the second pump and the cross-flow filter inlet may include an adsorption filter that may selectively remove contaminants, toxins, or pathogens in the permeate. A controller may control the first, second and third pumps to provide predetermined flow ratios among the fluid flow paths of the system in order to achieve a desired filtration level. This system may be applicable to the removal of harmful substances from blood, by first separating the plasma from the blood and then removing harmful substances from the plasma.

First claim

The invention claimed is:

1. A blood filtration apparatus comprising:
a source blood conduit configured to fluidly connect a source blood inlet to an inlet of a cross-flow plasma filter;
a recirculation conduit configured to recirculate plasma-separated blood from a retentate outlet of the cross-flow plasma filter to the inlet of the cross-flow plasma filter, forming a recirculation loop;
a first pump fluidly disposed within the recirculation loop and configured to recirculate plasma-separated blood from the retentate outlet to the inlet of the cross-flow plasma filter,
an outlet conduit from the recirculation loop fluidly connected to a first outlet of the blood filtration apparatus;
a plasma permeate conduit fluidly connecting a plasma permeate outlet of the cross-flow plasma filter to an adsorption filter for adsorption filtering of plasma permeate;
an outlet of the adsorption filter connected to the recirculation loop; and
a second pump disposed within the plasma permeate conduit configured to pump plasma permeate between the plasma permeate outlet of the cross-flow plasma filter and the adsorption filter; wherein
the second pump is configured to pump a quantity of the plasma permeate into the recirculation loop.

2. The apparatus of claim 1 , wherein the outlet of the adsorption filter is connected to the source blood conduit.

3. The apparatus of claim 1 , further comprising a third pump disposed within the source blood conduit, the third pump configured to pump a source of blood into the recirculation loop.

4. The apparatus of claim 1 , further comprising a flow restrictor within the outlet conduit.

5. The apparatus of claim 1 , further comprising a valve disposed within the plasma permeate conduit and a variable volume chamber interposed between the valve and the second pump, wherein the variable volume chamber is configured to fill with plasma permeate upon closure of the valve.

6. The apparatus of claim 1 , wherein the first pump or the second pump comprises a peristaltic pump, a centrifugal pump, an axial pump, a diaphragm pump or a reciprocating pump.

7. A filtration system comprising:
a source fluid conduit configured to fluidly connect a source fluid inlet to an inlet of a cross-flow filter;
a recirculation conduit configured to recirculate fluid from a retentate outlet of the cross-flow filter to the inlet of the cross-flow filter, forming a recirculation loop;
a first pump fluidly disposed within the recirculation loop and configured to recirculate fluid from the retentate outlet to the inlet of the cross-flow filter,
an outlet conduit from the recirculation loop fluidly connected to a first outlet of the filtration system;
a permeate conduit fluidly connecting a permeate outlet of the cross-flow filter to an adsorption filter for adsorption of permeate;
an outlet of the adsorption filter connected to the recirculation loop;
a second pump disposed within the permeate conduit configured to pump permeate between the permeate outlet of the cross-flow filter and the recirculation loop;
a third pump disposed within the source fluid conduit, the third pump configured to pump a source fluid into the recirculation loop;
a controller configured to control the first, second and third pumps,
wherein the controller controls the first, second or third pumps so that a predetermined fraction of the permeate is returned to the recirculation loop.

8. The filtration system of claim 7 , wherein the controller is configured to control the output of the second pump or the third pump to be a predetermined fraction of the output of the first pump.

9. The filtration system of claim 7 , wherein the permeate conduit comprises a first branch fluidly connected to the recirculation loop and a second branch fluidly connected to the outlet conduit, a valve being interposed at a junction of the branches to selectively restrict fluid flow in one or both of the branches.

10. The filtration system of claim 9 , wherein the source fluid is blood, the cross-flow filter is a plasma filter, and a hematocrit sensor is positioned in the recirculation loop, and wherein the controller receives data from the hematocrit sensor and is configured to adjust the valve to regulate flow to the first branch based on the hematocrit data.

11. A filtration method comprising the steps:
supplying fluid from a source to an inlet of a cross-flow filter;
recirculating fluid from a retentate outlet of the cross-flow filter to the inlet of the cross-flow filter;
passing a permeate fluid from a permeate outlet of the cross-flow filter through an adsorption filter;
recirculating the permeate fluid from an outlet of the adsorption filter to the inlet of the cross-flow filter;
returning a portion of the fluid from the retentate outlet of the cross-flow filter to the source.

12. A blood filtration system comprising:
a source blood conduit configured to fluidly connect a source blood inlet to an inlet of a cross-flow plasma filter;
a recirculation conduit configured to recirculate plasma-separated blood from a retentate outlet of the cross-flow plasma filter to the inlet of the cross-flow plasma filter, forming a recirculation loop;
a first pump fluidly disposed within the recirculation loop and configured to recirculate plasma-separated blood from the retentate outlet to the inlet of the cross-flow plasma filter;
an outlet conduit from the recirculation loop fluidly connected to a first outlet of the blood filtration system;
a plasma permeate conduit fluidly connecting a plasma permeate outlet of the cross-flow plasma filter to an adsorption filter for adsorption filtering of plasma permeate;
an outlet of the adsorption filter connected to the recirculation loop;
a second pump configured to pump plasma permeate between the plasma permeate outlet of the cross-flow plasma filter and the adsorption filter, or between the adsorption filter and the recirculation loop; and
a controller configured to control the first and second pumps,
wherein the controller controls the first and second pumps so that a predetermined fraction of the plasma permeate is returned to the recirculation loop.

13. The blood filtration system of claim 12 , wherein the controller controls the first and second pumps so that the output of the second pump is a predetermined fraction of the output of the first pump.

14. The blood filtration system of claim 12 , wherein the plasma permeate conduit comprises a first branch fluidly connected to the recirculation loop and a second branch fluidly connected to the outlet conduit, and wherein the controller controls a valve at a junction of the branches to selectively restrict plasma permeate flow in one or both of the branches.

15. The blood filtration system of claim 14 , further comprising a hematocrit sensor positioned in the recirculation loop, wherein the controller is configured to receive data from the hematocrit sensor and is configured to adjust the valve to regulate flow of plasma permeate to the first branch based on the hematocrit data.

16. A blood filtration method comprising the steps:
supplying blood from a source to an inlet of a cross-flow plasma filter;
recirculating plasma-separated blood from a retentate outlet of the cross-flow plasma filter to the inlet of the cross-flow plasma filter;
passing a plasma permeate from a plasma permeate outlet of the cross-flow plasma filter through an adsorption filter;
recirculating a first portion of the plasma permeate from an outlet of the adsorption filter to the inlet of the cross-flow plasma filter;
returning a second portion of the plasma

Assignees

• Kenley Rodney S
• Larocque Ryan K
• Schnellinger Andrew A
• Deka Products Lp

Inventors

• Kenley Rodney S
• Larocque Ryan K
• Schnellinger Andrew A

Classifications

• B01D37/046

  by pressure measuring · CPC title

• A61M1/3472

  with treatment of the filtrate · CPC title

• A61M1/3486

  Biological, chemical treatment, e.g. chemical precipitation; treatment by absorbents · CPC title

• B01D24/48

  integrally combined with devices for controlling the filtration · CPC title

• A61M2202/206

  Viruses · CPC title