Method and apparatus for filtering suspension of medical and biological fluids or the like

• US 6,491,819 B2
• Filed: 09/18/2001
• Issued: 12/10/2002
• Est. Priority Date: 09/25/1996
• Status: Expired due to Term

• Current Assignee: Baxter International Inc.
• Original Assignee: Baxter International Inc.
• Inventors: Sternberg, Shmuel, Bellamy, David Jr., Prince, Paul R., Pekkarinen, Michael O.
• Primary Examiner(s): Drodge, Joseph W.
• Application Number:
  US09/954,734
• Publication Number:
  US 20020033367A1
• Time in Patent Office: 448 Days
• Field of Search: 210/321.38, 210/321.78, 210/321.87, 210/500.21, 210/500.22, 210/781, 210/497.01, 210/321.67
• US Class Current: 210/321.67
• CPC Class Codes: A61M 1/262 rotating
• CPC Class Codes: A61M 1/265 inducing Taylor vortices
• CPC Class Codes: A61M 1/34 Filtering material out of the blood by passing it through a membrane, i.e. hemofiltration or diafiltration
• CPC Class Codes: A61M 1/3403 Regulation parameters
• CPC Class Codes: A61M 1/341 by measuring the filtrate rate or volume
• CPC Class Codes: A61M 2202/0035 fluid leaving the cross-flow filter without having passed through the filtering element
• CPC Class Codes: A61M 2202/0042 filtrate, i.e. the fluid passing through the filter
• CPC Class Codes: A61M 2202/0429 Red blood cells; Erythrocytes
• CPC Class Codes: A61M 2202/0439 White blood cells; Leucocytes lymphocytes A61M2202/0407
• CPC Class Codes: A61M 2205/3334 Measuring or controlling the flow rate
• CPC Class Codes: B01D 2321/20 By influencing the flow
• CPC Class Codes: B01D 2321/2025 Tangential inlet
• CPC Class Codes: B01D 2321/2058 by vibration of the membrane, e.g. with an actuator
• CPC Class Codes: B01D 2321/2066 Pulsated flow
• CPC Class Codes: B01D 39/1692 Other shaped material, e.g. perforated or porous sheets
• CPC Class Codes: B01D 61/147 Microfiltration
• CPC Class Codes: B01D 61/22 Controlling or regulating
• CPC Class Codes: B01D 63/16 Rotary, reciprocated or vibrated modules
• CPC Class Codes: B01D 65/08 Prevention of membrane fouling or of concentration polarisation
• CPC Class Codes: B01D 69/02 characterised by their properties

Abstract

An apparatus is disclosed for separating a suspension comprising at least two types of particles which are differently sized or shaped and in which the first type of particle may be deformable at a relatively lower force or faster rate than the second type of particle. A housing is provided having a generally cylindrical inner surface in which is mounted a rotor having a generally cylindrical outer surface. The outer surface of the rotor is spaced from the inner surface of the housing to define a suspension processing gap. A filter membrane is provided on the surface of the rotor or the housing that has pores with substantially precisely dimensioned shapes and sizes to correspond substantially to the shape of the first type of particle, thus allowing passage of the first type of particle and blocking passage of the second type of particle. A suspension is directed into the processing gap for either a selected residence time in contact with the filter membrane and/or at a selected force.

Claims

1. Apparatus for separating a suspension comprising at least first and second types of particles of different shape, the first type of particle being deformable at a relatively faster rate than the second type of particle, the apparatus including:

a housing having a generally cylindrical inner surface;

a rotor having a generally cylindrical outer surface mounted for rotation in said housing, the outer surface of the rotor being spaced from the inner surface of the housing to define a suspension processing gap there between;

a filter membrane carried by the cylindrical surface of the rotor or the housing, the membrane having a side facing the suspension processing gap and a side facing the cylindrical surface upon which it is carried, the filter membrane having pores with substantially precisely dimensioned shapes and sizes, said pore shapes and sizes being dimensioned to correspond substantially to shape of the first type of particle to allow passage of the first type and to block passage of the second type of particle,

a suspension inlet in said housing communicating with the suspension processing gap to direct suspension into the processing gap for a selected residence time in contact with the filter membrane, and an outlet communicating with side of the filter membrane facing the cylindrical surface for removing the first type of suspension particle passing through the membrane, the residence time being less than that needed for the second type of particle to deform to a size and shape capable of passing through the membrane.

2. The apparatus of claim 1 in which the filter membrane is carried on the surface of the rotor and defines a curvilinear surface facing the processing gap.

3. The apparatus of claim 1 in which the pores are substantially rectangular in shape and have a width of approximately 1.0 to 3.5 microns and a length of approximately 6 to 14 microns.

4. The apparatus of claim 1 in which the rotor is adapted for rotation at speeds sufficient to create Taylor vortices in said processing gap.

5. The apparatus of claim 1 in which the membrane has a porosity of at least about 10%.

6. Apparatus for separating a suspension comprising at least first and second types of particles of different shape, the first type of particle being deformable at a relatively faster rate than the second type of particle, the apparatus including:

a housing having a generally cylindrical inner surface;

a rotor having a generally cylindrical outer surface mounted for rotation in said housing, the outer surface of the rotor being spaced from the inner surface of the housing to define a suspension processing gap there between;

a filter membrane carried by the cylindrical surface of the rotor or the housing, the membrane having a side facing the suspension processing gap and a side facing the cylindrical surface upon which it is carried, the filter membrane having pores with substantially precisely dimensioned shapes and sizes, said pore shapes and sizes being dimensioned to correspond substantially to shape of the first type of particle to allow passage of the first type and to block passage of the second type of particle,

a suspension inlet in said housing communicating with the suspension processing gap to direct suspension into the processing gap for contact with the filter membrane at a selected force, and an outlet communicating with the side of the filter membrane facing the cylindrical surface for removing the first type of suspension particle passing through the membrane, the contact force being less than that needed for the second type of particle to deform to a size and shape capable of passing through the membrane.

7. The apparatus of claim 6 in which the filter membrane is carried on the surface of the rotor and defines a curvilinear surface facing the processing gap.

8. The apparatus of claim 6 in which the pores are substantially rectangular in shape and have a width of approximately 1.0 to 3.5 microns and a length of approximately 6 to 14 microns.

9. The apparatus of claim 6 in which the rotor is adapted for rotation at speeds sufficient to create Taylor vortices in said processing gap.

10. The apparatus of claim 6 in which the membrane has a porosity of at least about 10%.