Method for composition for cleaning tubular systems employing moving three-phase lines

Patent metadata

Field	Value
Publication number	US-9492853-B2
Application number	US-201213371765-A
Country	US
Kind code	B2
Filing date	Feb 13, 2012
Priority date	Sep 30, 2008
Publication date	Nov 15, 2016
Grant date	Nov 15, 2016

Abstract

A method for cleaning an internal surface of a narrow diameter channel includes steps of: flowing a liquid cleaning medium and a gas through the narrow diameter channel under a flow regime that creates surface flow entities in contact with and sliding along the internal surface of the narrow diameter channel, the surface flow entities having three-phase contact lines and associated menisci, the surface flow entities detaching contaminants with which they come in contact from the internal surface of the narrow diameter internal surface of the narrow diameter channel; and rinsing the internal surface of the narrow diameter channel to remove residual liquid cleaning medium and detached contaminants from the channel.

First claim

We claim:

1. A method of cleaning an internal surface of a narrow diameter channel, the method comprising:
step (i) flowing a liquid cleaning medium and a gas through the narrow diameter channel under a flow regime that provides surface flow entities in contact with and sliding along the internal surface of the narrow diameter channel, said narrow diameter channel having a diameter of 1.8 millimeter or less, said surface flow entities having three-phase contact lines and associated menisci, said surface flow entities detaching contaminants with which they come in contact from the internal surface of the narrow diameter channel,
wherein the flow regime is Discontinuous Plug Flow, Discontinuous Plug Droplet Flow, or a combination of Discontinuous Plug Flow and Discontinuous Plug Droplet Flow, by pulsing aliquots of the liquid cleaning medium into the channel with a pulse time P t and having the liquid flow at a rate sufficient to form a flowing plug of cleaning medium pushed through the narrow diameter channel by a flowing gas, said flowing plug either remaining intact throughout the channel length or forming fragments, said fragments remaining attached to and sliding along the surface, said liquid plug and fragments detaching contaminants from the internal surface of the narrow diameter channel by the sweeping of the surface of the narrow diameter channel with the three-phase contact lines of the liquid plug or the fragments formed there from; and
step (ii) rinsing the internal surface of the narrow diameter channel to remove residual liquid cleaning medium and detached contaminants from the channel;
wherein during the step (i):
the detachment of contaminants from the internal surface of the narrow diameter channel is produced by a sweeping of the internal surface of the narrow diameter channel with the three-phase contact lines of the surface flow entities,
the cleaning medium is not predispersed in the gas as droplets before entering the channel,
less than 10% of the internal surface of the narrow diameter channel is covered by a contiguous annular film, and there is an absence of entrained liquid droplets in the gas.

2. A method according to claim 1 , wherein the internal surface of the narrow diameter channel is a hydrophobic surface.

3. A method according to claim 2 , wherein the cleaning medium exhibits an advancing contact angle greater than 50 degrees and a receding contact angle greater than zero with the hydrophobic surface.

4. A method according to claim 2 , wherein the cleaning medium exhibits an advancing contact angle greater than about 80 degrees and a receding contact angle greater than zero with the hydrophobic surface.

5. A method according to claim 1 , wherein the internal surface of the narrow diameter channel has a diameter less than 1 millimeter.

6. A method according to claim 1 , wherein the flowing plug has a length which is less than 10% of the length of the internal surface of the narrow diameter channel.

7. A method according to claim 1 , wherein the liquid has flow rate of about 5.0 to about 15.0 ml/minute, and is pulsed into the narrow diameter channel with a pulse time of about 0.1 sec to about 15.0 sec.

8. A method according to claim 1 , wherein the narrow diameter channel is about 0.6 mm in diameter, the liquid has a flow rate of about 5.0 to about 10.0 ml/minute, and is pulsed into the narrow diameter channel with a pulse time of about 0.1 to about 15.0 sec at a gas pressure at or below about 35 psi.

9. A method according to claim 1 , wherein the narrow diameter channel is about 1.2 mm in diameter, the liquid has a flow rate of about 5.0 to about 15.0 ml/minute, and is pulsed into the narrow diameter channel with a pulse time of about 0.1 to about 15.0 sec at a gas pressure at or below about 35 psi.

10. A method according to claim 1 , wherein the liquid has a flow rate of about 10.0 to about 30.0 ml/minute, and is pulsed into the narrow diameter channel with a pulse time of about 0.1 to about 15.0 sec at a gas pressure at or below about 35 psi.

11. A method according to claim 1 , wherein the liquid has a flow rate of about 15.0 to about 45.0 ml/minute, and is pulsed into the narrow diameter channel with a pulse time of about 0.1 to about 15.0 sec at a gas pressure at or below about 35 psi.

12. A method according to claim 1 , wherein the liquid has a flow rate of about 25.0 to about 65.0 ml/minute, and is pulsed into the narrow diameter channel with a pulse time of about 0.1 to about 15.0 sec at a gas pressure at or below about 35 psi.

13. A method according to claim 1 , wherein the number of aliquots pulsed into the narrow diameter channel over a cleaning cycle is about 10 to about 1000 pulses per cleaning cycle.

14. A method according to claim 1 , wherein the narrow diameter channel comprises a capillary.

15. A method according to claim 14 , wherein the method comprises cleaning internal surfaces of a plurality of capillaries.

16. A method according to claim 15 , wherein the plurality of capillaries are in a hemodialyzer.

17. A method according to claim 1 , wherein the contaminants comprise blood serum and platelets.

18. A method according to claim 1 , wherein the contaminants comprise protein films or flakes.

19. A method according to claim 1 , wherein the step of rinsing comprises rinsing with water provided as a single phase liquid flow.

20. A method according to claim 1 , wherein the narrow diameter channel has a diameter of 0.2 millimeter to 1.8 millimeter.

21. A method of cleaning an internal surface of a narrow diameter channel, the method comprising:
step (i) flowing a liquid cleaning medium and a gas through the narrow diameter channel under a flow regime that provides surface flow entities in contact with and sliding along the internal surface of the narrow diameter channel, said narrow diameter channel having a diameter of 1.8 millimeter or less, said surface flow entities having three-phase contact lines and associated menisci, said surface flow entities detaching contaminants with which they come in contact from the internal surface of the narrow diameter channel, by pulsing aliquots of the liquid cleaning medium into the channel with a pulse time Pt and having the liquid flow at a rate sufficient to form a flowing plug of cleaning medium pushed through the narrow diameter channel by a flowing gas, said flowing plug either remaining intact throughout the channel length or forming fragments, said fragments remaining attached to and sliding along the surface, said liquid plug and fragments detaching contaminants from the internal surface of the narrow diameter channel by the sweeping of the surface of the narrow diameter channel with the three-phase contact lines of the liquid plug or the fragments formed there from; and
step (ii) rinsing the internal surface of the narrow diameter channel to remove residual liquid cleaning medium and detached contaminants from the channel;
wherein during the step (i):
the detachment of contaminants from the internal surface of the narrow diameter channel is produced by a sweeping of the internal surface of the narrow diameter channel with the three-phase contact lines of the surface flow entities,
the cleaning medium is not predispersed in the gas as droplets before entering the channel,
less than 10% of the internal surface of the narrow diameter channel is covered by a contiguous annular film, and there is an absence of entrained liquid droplets in the gas.

22. A method according to claim 21 , w

Assignees

• Labib Mohamed Emam
• Dukhin Stanislav S
• Murawski Joseph J
• Tabani Yacoob
• Lai Ching-Yue
• Olympus Corp

Inventors

• Labib Mohamed Emam
• Dukhin Stanislav S
• Murawski Joseph J
• Tabani Yacoob
• Lai Ching-Yue

Classifications

• B08B9/032 Primary

  by the mechanical action of a moving fluid, e.g. by flushing (B08B9/04 takes precedence {; by fluid jets mounted on cleaning devices B08B9/0433}) · CPC title

• B08B9/0326

  Using pulsations · CPC title

• B08B9/0325

  Control mechanisms therefor · CPC title