Microfluidic mixers

Patent metadata

Field	Value
Publication number	US-12383876-B2
Application number	US-202217826943-A
Country	US
Kind code	B2
Filing date	May 27, 2022
Priority date	May 27, 2022
Publication date	Aug 12, 2025
Grant date	Aug 12, 2025

Abstract

An example microfluidic mixer can include an inlet microfluidic channel portion and a fluid splitting channel portion including an overpass microfluidic channel to receive fluid from a first side of the inlet microfluidic channel portion and an underpass microfluidic channel to receive fluid from a second side of the inlet microfluidic channel portion, where the underpass microfluidic channel extends under the overpass microfluidic channel such that the channels overlap at their respective downstream ends. A fluid recombining channel portion is downstream of the fluid splitting portion and includes an angled recombining surface having an acute angle with respect to a direction of fluid flow, where the angled recombining surface is between the downstream ends of the overpass and underpass microfluidic channels. An outlet microfluidic channel portion is fluidly connected downstream from the fluid recombining channel portion.

First claim

What is claimed is:

1. A microfluidic mixer, comprising:
an inlet microfluidic channel portion;
a fluid splitting channel portion downstream from the inlet microfluidic channel portion, wherein the fluid splitting channel portion comprises:
an overpass microfluidic channel fluidly connected to the inlet microfluidic channel portion to receive fluid from a first side of the inlet microfluidic channel portion, and
an underpass microfluidic channel fluidly connected to the inlet microfluidic channel portion to receive fluid from a second side of the inlet microfluidic channel portion, wherein the underpass microfluidic channel extends under the overpass microfluidic channel such that a downstream end of the overpass microfluidic channel overlaps with a downstream end of the underpass microfluidic channel;

a fluid recombining channel portion downstream from the fluid splitting channel portion, wherein the fluid recombining channel portion is fluidly connected to the overpass microfluidic channel and the underpass microfluidic channel, wherein the fluid recombining channel portion comprises an angled recombining surface having an acute angle with respect to a direction of fluid flow through the fluid recombining channel portion, and wherein the angled recombining surface is between the downstream end of the overpass microfluidic channel and the downstream end of the underpass microfluidic channel; and
an outlet microfluidic channel portion fluidly connected to the fluid recombining channel portion to receive recombined fluid from the fluid recombining channel portion.

2. The microfluidic mixer of claim 1 , further comprising a lower layer of photoresist material, a middle layer of photoresist material over the lower layer, and an upper layer of photoresist material over the middle layer; wherein the inlet microfluidic channel portion and the outlet microfluidic channel are both three-layer-high channels formed in the lower layer, middle layer, and upper layer; wherein the overpass microfluidic channel is a single-layer-high channel formed in the upper layer; wherein the underpass microfluidic channel is a single-layer-high channel formed in the lower layer; and wherein the overpass microfluidic channel is separated from the underpass microfluidic channel by solid photoresist material in the middle layer.

3. The microfluidic mixer of claim 1 , wherein the angled recombining surface has a saw tooth shape including multiple angled faces, wherein an angle between adjacent angled faces is from 5° to 45°.

4. The microfluidic mixer of claim 1 , wherein the overpass microfluidic channel comprises a first outwardly concave curved sidewall; wherein a fluid cross-sectional area of the overpass microfluidic channel increases in a fluid flow direction along the first outwardly concave curved sidewall; wherein the underpass microfluidic channel comprises a second outwardly concave curved sidewall curving in an opposite direction to the first outwardly concave curved sidewall; and wherein a fluid cross-sectional area of the underpass microfluidic channel increases in a fluid flow direction along the second outwardly concave curved sidewall.

5. The microfluidic mixer of claim 1 , further comprising a fluid splitting element in the fluid splitting channel portion, extending upstream from an upstream end of the overpass microfluidic channel and an upstream end of the underpass microfluidic channel, wherein the fluid splitting element divides fluid from the first and second sides of the inlet microfluidic channel portion.

6. The microfluidic mixer of claim 5 , wherein the fluid splitting channel portion further comprises a first angled end wall to direct fluid from the first side of the inlet microfluidic channel portion into the overpass microfluidic channel, wherein the first angled end wall is positioned below the upstream end of the overpass microfluidic channel, wherein the first angled end wall forms an acute angle with a sidewall of the fluid splitting channel portion; and wherein the fluid splitting channel portion further comprises a second angled end wall to direct fluid from the second side of the inlet microfluidic channel portion into the underpass microfluidic channel, wherein the second angled end wall is positioned above the upstream end of the underpass microfluidic channel, wherein the second angled end wall forms an acute angle with an opposite sidewall of the fluid splitting channel portion.

7. The microfluidic mixer of claim 1 , further comprising a solid support pillar in the overpass microfluidic channel, or the underpass microfluidic channel, or both, wherein the solid support pillar has a tapered downstream edge having an acute angle such that a fluid cross-sectional area increases in the fluid flow direction along the tapered downstream edge.

8. The microfluidic mixer of claim 1 , wherein the inlet microfluidic channel portion and the outlet microfluidic channel portion have a width from 20 μm to 300 μm and a height from 6 μm to 100 μm.

9. A method of mixing fluid, comprising:
introducing a fluid into an inlet microfluidic channel portion of a microfluidic mixer;
dividing the fluid into a first portion of fluid on a first side of the inlet microfluidic channel portion and a second portion of fluid on a second side of the inlet microfluidic channel portion;
flowing, by capillary action, the first portion through an overpass microfluidic channel;
flowing, by capillary action, the second portion through an underpass microfluidic channel, wherein the underpass microfluidic channel extends under the overpass microfluidic channel such that a downstream end of the overpass microfluidic channel overlaps with a downstream end of the underpass microfluidic channel;
flowing, by capillary action, the first portion of fluid from the overpass microfluidic channel into a fluid recombining channel portion along an angled recombining surface;
flowing, by capillary action, the second portion of fluid from the underpass microfluidic channel into the fluid recombining channel portion along the angled recombining surface, thereby recombining the second portion of fluid with the first portion of fluid, wherein the angled recombining surface has an acute angle with respect to a direction of fluid flow through the fluid recombining channel portion, and wherein the angled recombining surface is between the downstream end of the overpass microfluidic channel and the downstream end of the underpass microfluidic channel; and
flowing, by capillary action, the recombined first portion and second portion of fluid from the fluid recombining channel portion into an outlet microfluidic channel portion.

10. The method of claim 9 , further comprising flowing the fluid from the outlet microfluidic channel portion through a series of multiple additional microfluidic mixers, wherein a total number of microfluidic mixers is from 4 to 20.

11. The method of claim 9 , wherein no additional pressure is applied to the fluid flowing through the microfluidic mixer besides the capillary action.

Assignees

• Hewlett Packard Development Co

Inventors

• Denison Carson
• Seaver Richard W
• Torniainen Erik D
• Kornilovich Pavel
• Govyadinov Alexander
• Jebakumar Anand Samuel
• El Fajri Oumnia

Classifications

• B01F35/7172

  using capillary forces · CPC title

• B01F2101/2204

  Mixing chemical components in generals in order to improve chemical treatment or reactions, independently from the specific application · CPC title

• B01F33/3012 Primary

  Interdigital streams, e.g. lamellae · CPC title