Pump for low flow rates

• US 20050006309A1
• Filed: 08/05/2004
• Published: 01/13/2005
• Est. Priority Date: 06/21/2000
• Status: Active Grant

• Current Assignee: Roche Diabetes Care Inc. (Roche Holding AG)
• Original Assignee: Carlo Effenhauser, Herbert Harttig, Peter Kraemer
• Inventors: Kraemer, Peter, Harttig, Herbert, Effenhauser, Carlo
• Granted Patent: US 6,872,315 B2
• Time in Patent Office: Days
• US Class Current: 210/637
• CPC Class Codes: F04B 17/00 Pumps characterised by combination with, or adaptation to, specific driving engines or motors
• CPC Class Codes: F04B 43/06 Pumps having fluid drive
• CPC Class Codes: Y10T 436/2575 Volumetric liquid transfer

Abstract

The present invention concerns a method of producing flow rates of a transport liquid of about 1 to 1000 nl/min. The method provides a pump having a housing defining a space and including a channel and a wettable membrane positioned in the housing, the membrane including a first side facing toward the channel and a second side facing the space. The method further includes at least partially filling the channel with the transport liquid, contacting the wettable membrane with the transport liquid to generate an underpressure in the channel,evaporating the transport liquid at the wettable membrane to remove the transport liquid from the channel and to create an underpressure in the channel, and maintaining a generally constant vapour pressure of the transport liquid in the space.

Claims

1. A method of producing flow rates of a transport liquid of about 1 to 1000 nl/min, the method comprising the steps of:

providing a pump comprising a housing defining a space and including a channel and a wettable membrane positioned in the housing, the membrane including a first side facing toward the channel and a second side facing the space,

at least partially filling the channel with the transport liquid,

contacting the wettable membrane with the transport liquid to generate an underpressure in the channel,

evaporating the transport liquid at the wettable membrane to remove the transport liquid from the channel and to create an underpressure in the channel, and

maintaining a generally constant vapour pressure of the transport liquid in the space.

2. The method of claim 1 wherein the transport liquid penetrates the membrane due to capillary effects.

3. The method of claim 2 wherein the transport liquid evaporates through the membrane.

4. The method of claim 1 further comprising the step of at least partially filling the channel with a working liquid.

5. The method of claim 4 further comprising the step of segmenting the transporting and working liquids.