Method of preventing air from becoming entrapped within a filtration device

• US 6,251,292 B1
• Filed: 11/04/1999
• Issued: 06/26/2001
• Est. Priority Date: 03/10/1994
• Status: Expired due to Term

• Current Assignee: Pall Corporation (Danaher Corporation)
• Original Assignee: HemaSure, Inc.
• Inventors: Zuk, Peter Jr.
• Primary Examiner(s): Kim, John
• Application Number:
  US09/434,182
• Time in Patent Office: 600 Days
• Field of Search: 210/650, 210/767, 210/435, 210/436, 210/456, 210/472, 210/498, 210/416.1
• US Class Current: 210/767
• CPC Class Codes: A61M 1/0209 Multiple bag systems for separating or storing blood components
• CPC Class Codes: A61M 1/0218 with filters
• CPC Class Codes: A61M 1/0231 with gas separating means, e.g. air outlet through microporous membrane or gas bag
• CPC Class Codes: A61M 1/3627 Degassing devices; Buffer reservoirs; Drip chambers; Blood filters
• CPC Class Codes: A61M 1/3633 Blood component filters, e.g. leukocyte filters
• CPC Class Codes: A61M 1/3643 Priming, rinsing before or after use
• CPC Class Codes: A61M 1/3652 using gas, e.g. air
• CPC Class Codes: A61M 2202/005 residue retained by the filter due to size
• CPC Class Codes: A61M 2202/0439 White blood cells; Leucocytes lymphocytes A61M2202/0407
• CPC Class Codes: A61M 2205/7536 allowing gas passage, but preventing liquid passage, e.g. liquophobic, hydrophobic, water-repellent membranes
• CPC Class Codes: B01D 19/0031 by filtration
• CPC Class Codes: B01D 36/001 Filters in combination with devices for the removal of gas, air purge systems
• CPC Class Codes: B01D 61/18 Apparatus therefor
• CPC Class Codes: B01D 61/20 Accessories; Auxiliary operations
• CPC Class Codes: B01D 63/08 Flat membrane modules

Abstract

An in-line gravity filtration device for biological fluids such as blood or blood products is disclosed. The device includes a series of channels formed downstream of filtration elements. The channels are defined in cross sectional area by the distance between the filtration elements and their bottoms. The channels are configured to form flow paths to an outlet port so that air within the channels is forced downstream through the outlet port thereby minimizing air being trapped on the downstream side of the device. For optimum performance, the cross section area of a single continuous channel, or the sum of the cross sectional area of parallel channels, leading to a single outlet port, should not exceed the cross sectional area of the outlet port.

Claims

1. A method of preventing air from becoming entrapped within a filtration device of a biological liquid filtration system comprising:

flowing biological liquid through said filtration system and through said filtration device;

utilizing gravity to create a negative pressure downstream of a filtration media within said filtration device; and

forcing air within said filtration device downstream of said filtration media to flow through an outlet at a flow rate sufficient to force air to flow into the outlet of said device and utilizing said negative pressure downstream of said filtration media to force air within said filtration device downstream of said filtration media to flow through said outlet after biological liquid flows through said outlet thereby preventing air from becoming trapped downstream of said filtration media within said filtration device.

2. The method of claim 1 further comprising forcing air located downstream of said filtration device to flow into a flow path comprising a first channel leading to said outlet of said device using filtered biological liquid.

3. The method of claim 2 further comprising flowing filtered biological liquid from a second channel into said first channel at a flow rate sufficient to force air from within said second channel into said first channel.

4. The method of claim 3 further comprising flowing filtered biological liquid from parallel channels into the second channel at a flow rate sufficient to force air from said parallel channels into said second channel.

5. The method of claim 4 further comprising flowing filtered biological liquid from cross flow channels into the parallel channels at a flow rate sufficient to force air therein into said parallel channels.

6. The method of claim 1 further comprising allowing biological liquid to remain within a tube located downstream of said filtration media.

7. The method of claim 1 wherein said biological liquid is filtered for the removal of cells.

8. The method of claim 1 wherein said biological liquid is filtered for the removal of chemical agents.

9. The method of claim 1 wherein said biological liquid is blood or a blood product.

10. The method of claim 9 further comprising forcing air located downstream of said filtration device to flow into a flow path comprising a first channel leading to said outlet of said device using filtered blood or blood product.

11. The method of claim 10 further comprising flowing filtered blood or blood product from a second channel into said first channel at a flow rate sufficient to force air from within said second channel into said first channel.

12. The method of claim 11 further comprising flowing filtered blood or blood product from parallel channels into the second channel at a flow rate sufficient to force air from said parallel channels into said second channel.

13. The method of claim 12 further comprising flowing filtered blood or blood product from cross flow channels into the parallel channels at a flow rate sufficient to force air therein into said parallel channels.

14. The method of claim 9 further comprising allowing blood or blood product to remain within a tube located downstream of said filtration media.

15. The method of claim 9 wherein said blood or blood product is filtered for the removal of cells.

16. The method of claim 9 wherein said blood or blood product is filtered for the removal of chemical agents.

17. The method of claim 3 further comprising allowing biological liquid to remain within a tube located downstream of said filtration media.

18. The method of claim 3 wherein said biological liquid is filtered for the removal of cells.

19. The method of claim 3 wherein said biological liquid is filtered for the removal of chemical agents.