# US 2014/0190884 A1 · Compact hydraulic manifold structure for shear sensitive fluids > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0190884 A1 - Document ID: US20140190884A1 - Status: Published application - Kind: A1 - Application number: 13/736,685 - Filed: 2013-01-08 - Published: 2014-07-10 - Earliest claimed: 2013-01-08 - Assignees: The Charles Stark Draper Laboratory, Inc. - Applicants: The Charles Stark Draper Laboratory - Inventors: Christopher DiBiasio; Joseph L. Charest; Jeffrey T. Borenstein; Ernest S. Kim; Daniel I. Harjes; Kevin Hufford - Web page: https://patentgrep.com/patent/US20140190884A1 ## CPC - B01D 63/088: {Microfluidic devices comprising semi-permeable flat membranes} - B01L 3/502746: {characterised by the means for controlling flow resistance, e.g. flow controllers, baffles or throttle valves} - B01D 61/28: Apparatus therefor - B01D 63/085: {specially adapted for two fluids in mass exchange flow} - B01D 2201/0415: Details of supporting structures - B01D 2313/08: Flow guidance means within the module or the apparatus - B01L 2300/0864: comprising only one inlet and multiple receiving wells, e.g. for separation, splitting - B01L 2300/0874: Three dimensional network - B01L 2300/0887: Laminated structure - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) - B01L: CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE ## Abstract An compact hydraulic manifold for transporting shear sensitive fluids is provided. A channel network can include a trunk and branch architecture coupled to a bifurcation architecture. Features such as tapered channel walls, curvatures and angles of channels, and zones of low fluid pressure can be used to reduce the size while maintaining wall shear rates within a narrow range. A hydraulic manifold can be coupled to a series of microfluidic layers to construct a compact microfluidic device. ## Claims ### Claim 1 A microfluidic device comprising: a first network of channels having a plurality of First Channels, each First Channel having a height in the range of about 50 microns to about 500 microns, a width in the range of about 50 microns to about 1.5 millimeters, and a length in the range of about 3 centimeters to about 20 centimeters; a second network of channels having at least one Second Channel complementary to one or more of the First Channels; a filtration membrane separating the one or more First Channels from the at least one Second Channel; wherein the plurality of First Channels further comprises: an input channel forming a primary channel, a plurality of secondary channels, and an outlet channel, wherein the primary channel bifurcates into first and second secondary channels at a first junction, such that a fluid flow rate through the first secondary channel is substantially the same as a fluid flow rate through the second secondary channel, and the total fluid flow rate between the first and second secondary channels is substantially the same as the fluid flow rate through the primary channel; a first tertiary channel connecting to the first secondary channel at a second junction located at a first distance along the first secondary channel; and a second tertiary channel connecting to the first secondary channel at a third junction located at a second distance, greater than the first distance, along the first secondary channel, wherein the first secondary channel and the first and second tertiary channels are configured such that flow of fluid through the first secondary channel beyond the second junction is substantially greater than flow of fluid into the first secondary channel. ### Claim 2 (depends on 1) The microfluidic device of claim 1, wherein the plurality of First Channels is located within a first substrate. ### Claim 3 (depends on 2) The microfluidic device of claim 2, wherein the first substrate has a thickness of no less than 50 microns and no greater than 10 millimeters. ### Claim 4 (depends on 1) The microfluidic device of claim 1, wherein the filtration membrane separates only a subset of the plurality of First Channels from the at least one Second Channel. ### Claim 5 (depends on 1) The microfluidic device of claim 1, wherein at least one of the first and second tertiary channels bifurcates into first and second quaternary channels at a fourth junction, such that a fluid flow rate through the first quaternary channel is substantially the same as a fluid flow rate through the second quaternary channel, and the total fluid flow rate through the first and second quaternary channels is substantially the same as the fluid flow rate through the portion of the at least one tertiary channel between the first secondary channel and the fourth junction. ### Claim 6 (depends on 5) The microfluidic device of claim 5, further comprising a flow divider for dividing fluid flow between the first and second quaternary channels, wherein the flow divider has a curved surface connecting to the walls of the first and second quaternary channels, and the radius of curvature of the flow divider is not greater than the hydraulic diameter of the at least one tertiary channel. ### Claim 7 (depends on 5) The microfluidic device of claim 5, further comprising third and fourth quaternary channels that converge at a point where they have opposing curvatures to form a third tertiary channel, such that all of the fluid flowing through the third and fourth quaternary channels is subsequently transported into the third tertiary channel. ### Claim 8 (depends on 1) The microfluidic device of claim 1, wherein the diameter of at least one tertiary channel at a portion adjacent to its junction with the secondary channel is significantly greater than the diameter of the downstream portion of the at least one tertiary channel, such that a zone of low fluid pressure is created at the junction. ### Claim 9 (depends on 1) The microfluidic device of claim 1, wherein an angle formed by a centerline of at least one tertiary channel and a downstream portion of the centerline of the secondary channel to which the at least one tertiary channel connects measures between one and sixty degrees. ### Claim 10 (depends on 1) The microfluidic device of claim 1, wherein the plurality of First Channels is further configured to maintain a shear rate of no less than two hundred inverse seconds and no more than two thousand inverse seconds when blood is transported through the channels. ### Claim 11 (depends on 1) The microfluidic device of claim 1, wherein the walls of the primary channel are disposed at an angle of no greater than thirty degrees with respect to the direction of fluid flow through the primary channel. ### Claim 12 (depends on 1) The microfluidic device of claim 1, wherein at least one tertiary channel includes a curved portion directing flow away from at least one secondary channel. ### Claim 13 (depends on 12) The microfluidic device of claim 12, wherein the curved portion of the at least one tertiary channel has a radius of curvature that is not less than its hydraulic diameter. ### Claim 14 (depends on 1) The microfluidic device of claim 1, wherein at least one of the plurality of First Channels or the at least one Second Channel has a substantially semicircular cross section. ### Claim 15 (depends on 1) The microfluidic device of claim 1, wherein at least one of the plurality of First Channels or the at least one Second Channel has substantially flat top and bottom walls joined by curved sidewalls.