# US 10,478,818 B1 · Check valves for microfluidic systems and methods thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,478,818 B1 - Document ID: US10478818B1 - Status: Granted - Kind: B1 - Application number: 15/447,581 - Filed: 2017-03-02 - Granted: 2019-11-19 - Earliest claimed: 2016-03-24 - Assignees: National Technology & Engineering Solutions of Sandia, LLC - Applicants: National Technology & Engineering Solutions of Sandia, LLC - Inventors: Cameron Scott Ball; Ronald F. Renzi; Robert Meagher - Web page: https://patentgrep.com/patent/US10478818B1 ## CPC - B01L 3/502738: {characterised by integrated valves (throttle valves in microfluidic sample containers B01L3/502746)} - F16K 99/0005: {Lift valves} - B01L 3/502707: {characterised by the manufacture of the container or its components} - B01L 3/502715: {characterised by interfacing components, e.g. fluidic, electrical, optical or mechanical interfaces} - B01L 3/50273: {characterised by the means or forces applied to move the fluids} - F16K 99/0009: {the valve element held by multiple arms} - F16K 99/0015: {Diaphragm or membrane valves} - F16K 99/0057: {the fluid being the circulating fluid itself, e.g. check valves} - B01L 2200/10: Integrating sample preparation and analysis in single entity, e.g. lab-on-a-chip concept - B01L 2200/12: Specific details about manufacturing devices - B01L 2300/049: Valves integrated in closure - B01L 2300/0887: Laminated structure - B01L 2400/0487: fluid pressure, pneumatics - B01L 2400/0605: check valves - F16K 2099/008: {Multi-layer fabrications} - F16K 2099/0084: {Chemistry or biology, e.g. "lab-on-a-chip" technology} - F16K 2099/0094: {Micropumps} - B01L: CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE - F16K: VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING {(devices for emptying and evacuating the excess liquid in valves or conduits F16L55/07)} ## Abstract The present invention relates to microfluidic check valves, as well as fluidic cartridges including such check valves. In particular examples, the check valve includes a pre-stressed spring formed from a planar substrate. Various characteristics of the valves, such as size, profile, opening pressure, etc., can be tuned to provide desired performance when employed within a fluidic cartridge. ## Claims ### Claim 1 A fluidic check valve comprising: a base comprising an inlet; an elastomeric pad comprising a first surface and a second surface that opposes the first surface, wherein the first surface is configured to releasably contact the inlet; a pre-stressed spring comprising a plurality of extended beams defined within a planar substrate and connected to a central support, wherein a surface portion of the substrate is configured to contact a surface portion of the base, and wherein the central support is defined within the substrate and configured to align with the second surface of the elastomeric pad, thereby providing a pressurized seal between the inlet of the base, the elastomeric pad, and the central support of the pre-stressed spring; and a lid comprising a cavity, wherein the cavity is configured to encompass the pre-stressed spring and the elastomeric pad. ### Claim 2 (depends on 1) The valve of claim 1, wherein the base further comprises an outlet configured to be in fluidic communication with the inlet upon displacement of the elastomeric pad away from the inlet. ### Claim 3 (depends on 1) The valve of claim 1, further comprising: a channel layer disposed between the planar substrate and the lid, wherein the channel layer comprises a chamber configured to accommodate a dimension the pre-stressed spring and a channel output configured to be in fluidic communication with the inlet upon displacement of the elastomeric pad away from the inlet. ### Claim 4 (depends on 1) The valve of claim 1, wherein the elastomeric pad and the pre-stressed spring comprises a single structure. ### Claim 5 (depends on 1) The valve of claim 1, wherein the base further comprises a ridge surrounding the inlet. ### Claim 6 (depends on 5) The valve of claim 5, wherein the elastomeric pad further comprises an indent configured to accommodate the ridge, thereby providing a seal between the ridge and the indent. ### Claim 7 (depends on 1) The valve of claim 1, wherein the base further comprises a recess configured to accommodate the planar substrate of the pre-stressed spring. ### Claim 8 (depends on 1) The valve of claim 1, wherein the lid is further configured to contact a surface portion of the base. ### Claim 9 (depends on 1) The valve of claim 1, wherein the cavity is configured to provide a conformal surface in proximity to a surface profile of the pre-stressed spring. ### Claim 10 (depends on 1) The valve of claim 1, in which the check valve is a microfluidic check valve. ### Claim 11 (depends on 1) The valve of claim 1, further comprising an adhesive layer disposed between the base and the planar substrate. ### Claim 12 (depends on 1) The valve of claim 1, wherein a first material for the planar substrate is different than a second material for the elastomeric pad. ### Claim 13 (depends on 1) The valve of claim 1, wherein the planar substrate comprises a laser-cut thermoplastic. ### Claim 14 (depends on 1) The valve of claim 1, in which the check valve is a normally closed check valve. ### Claim 15 (depends on 1) The valve of claim 1, further comprising an adhesive layer disposed between the planar substrate and the lid. ### Claim 16 (depends on 1) The valve of claim 1, wherein the elastomeric pad comprises silicone. ### Claim 17 (depends on 1) The valve of claim 1, further comprising a thin elastomeric coating on a surface of the base. ### Claim 18 (depends on 5) The valve of claim 5, wherein the ridge is a concentric annular boss. ### Claim 19 (depends on 18) The valve of claim 18, wherein the elastomeric pad rests against the concentric annular boss over the inlet. ### Claim 20 (depends on 1) The valve of claim 1, wherein the pre-stressed spring is formed from polymethyl methacrylate or polyethylene terephthalate.