Arrangement for mixing fluids in a capillary driven fluidic system
Inventors
Assignees
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Publication Number
US-11590498-B2
Publication Date
2023-02-28
Expiration Date
Abstract
There is provided an arrangement (100) which allows for mixing a first fluid with a second fluid at a predetermined volume mixing ratio in a capillary driven fluidic system. The arrangement (100) allows filling an initially empty mixing chamber (110) with the first fluid. The arrangement then allows emptying a predetermined fraction of the first fluid from the mixing chamber (110) such as to form an empty space in the mixing chamber (110). The arrangement then allows filling the empty space of the mixing chamber (110) with the second fluid, thereby allowing a predetermined volume of the first fluid to mix with a predetermined volume of the second fluid over time.
Core Innovation
The arrangement in a capillary driven fluidic system mixes a first fluid with a second fluid at a predetermined volume mixing ratio using a mixing chamber that includes a main chamber and one or more inner chambers. The main chamber and each inner chamber are separated by a respective structure including at least one opening that allows for fluid communication between the chambers. During use, the opening is arranged to generate a capillary pressure (CP2) larger than a capillary pressure (CP3) in the main chamber.
The mixing chamber extends in a longitudinal direction (D), and the main chamber extends along a full length of the mixing chamber. The mixing chamber is arranged to receive the first fluid so as to fill the main chamber and the one or more inner chambers via the respective at least one opening. A capillary pump draws fluid from the main chamber after the main chamber and the one or more inner chambers have been filled with the first fluid, wherein the capillary pump operates at a capillary pressure (CP1) between CP3 and CP2 such that the main chamber but not the one or more inner chambers is emptied of the first fluid.
After the main chamber has been emptied, the mixing chamber is arranged to receive the second fluid so as to fill the main chamber with the second fluid. The first fluid in the one or more inner chambers and the second fluid in the main chamber are enabled to mix through the at least one opening of the respective structure. This mixing behavior is achieved by using the relative capillary pressure arrangement to selectively empty only the main chamber before refilling it.
Claims Coverage
The independent claim covers an arrangement for capillary-driven two-fluid mixing at a predetermined volume mixing ratio using selective emptying of a main chamber based on relative capillary pressures (CP1, CP2, CP3). The key inventive features in the independent claim and its identified dependent refinements relate to chamber/opening capillary-pressure relationships, longitudinal geometry, and additional components for delivery and timing of the second-fluid refill sequence.
Selective emptying of the main chamber by intermediate capillary pressure operation
A capillary pump draws fluid from the main chamber after the main chamber and the one or more inner chambers have been filled with the first fluid, wherein the capillary pump is arranged to operate at a capillary pressure (CP1) between the capillary pressure (CP3) of the main chamber and the capillary pressure (CP2) in the at least one opening such that the main chamber but not the one or more inner chambers is emptied of the first fluid.
Capillary-pressure hierarchy between openings and the main chamber
A mixing chamber including a main chamber and one or more inner chambers is arranged so that the main chamber and each inner chamber are separated by a respective structure each including at least one opening which is arranged to generate a capillary pressure (CP2) in the at least one opening larger than a capillary pressure (CP3) in the main chamber.
Two-stage filling to enable mixing through openings
The mixing chamber is arranged to receive a first fluid so as to fill the main chamber and the one or more inner chambers via the respective at least one opening, and then to receive a second fluid so as to fill the main chamber after the main chamber has been emptied of the first fluid, such that the first fluid in the one or more inner chambers and the second fluid in the main chamber are enabled to mix through the at least one opening.
Longitudinal extension of the mixing chamber with full-length main chamber
The mixing chamber extends in a longitudinal direction (D) and the main chamber extends in said longitudinal direction (D) along a full length of the mixing chamber.
Equidistant pillar spacing to affect capillary pressure in openings
A structure includes a plurality of pillars arranged equidistantly at a spacing (W), wherein the capillary pressure (CP2) in the openings varies depending on that spacing.
Uniform cross section along the longitudinal direction to stabilize capillary pressure
The main chamber has a substantially uniform cross section along the longitudinal direction (D), making the capillary pressure (CP3) substantially constant.
First reservoir and capillary-driven first channel for first-fluid delivery
A first reservoir and a capillary-driven first channel deliver a first fluid into a mixing chamber and its main and inner chambers through respective openings.
Second reservoir and second channel/valve system for second-fluid refill
A second reservoir and second channel/valve system use capillary forces to draw a second fluid into the main chamber after the first fluid has been removed, thereby refilling the main chamber with the second fluid.
Overall, the claims coverage emphasizes a capillary-pressure-based sequence in which a capillary pump operates at an intermediate capillary pressure to empty only the main chamber while leaving first fluid in the one or more inner chambers, followed by refilling the main chamber with a second fluid so that mixing occurs through the openings. Dependent refinements identified in the provided material further specify structural and component features related to capillary pressure behavior and the delivery/timing of the first and second fluids.
Stated Advantages
Predetermined volume mixing ratio.
Largely independent of fluid viscosities.
Reduced mixing impact from macroscopic flow cessation.
Potential diagnostic/lab-on-chip measurement integration.
Documented Applications
A diagnostic device including the arrangement.
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