US 8,408,073 B2Granted

Microfluidic device and method of use

AssigneeIntegrated Sensing Systems, Inc.

InventorsDouglas Ray Sparks, Richard Thayre Smith, Nader Najafi

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Abstract

A microfluidic device and sensing method that utilize a resonating tube configured to have sufficient sensitivity to be capable of sensing the volume of a gas present as bubbles in a liquid or the flow rate and/or density of a gas or gas mixture flowing through the tube. The tube has a freestanding tube portion supported above a surface of a substrate so as to be capable of vibrating in a plane normal to the surface of the substrate. As a gas-containing fluid flows through an internal passage of the tube, a drive signal vibrates the freestanding tube portion at a resonant frequency thereof. Coriolis-induced deflections of the freestanding tube portion are sensed relative to the substrate to produce an output corresponding to the sensed deflections, and the drive signal and/or the output are assessed to determine the volume, density and/or flow rate of the gas of the gas-containing fluid.

Claims20

Dependent claims

A method of determining at least one property of a gas-containing fluid comprising at least a first gas in at least a first fluid, the method comprising:

providing a freestanding tube portion supported above a surface of a substrate so as to be capable of vibrating in a plane normal to the surface of the substrate, the freestanding tube portion having a continuous internal passage, a fluid inlet portion of the internal passage through which the gas-containing fluid enters the freestanding tube portion, and a fluid outlet portion of the internal passage through which the gas-containing fluid exits the freestanding tube portion;
flowing the gas-containing fluid through the internal passage of the freestanding tube portion;
generating a drive signal to vibrate the freestanding tube portion at a resonant frequency thereof and avoid alternative vibration modes of the freestanding tube portion, wherein the resonant frequency is proportional to the density of the gas-containing fluid, the Coriolis effect causes the freestanding tube portion to twist about an axis of symmetry thereof while being vibrated at the resonant frequency, and the freestanding tube portion exhibits a degree of twist that varies with the mass flow rate of the gas-containing fluid;
sensing deflections of the freestanding tube portion relative to the substrate and producing an output corresponding to the sensed deflections;
and
assessing the drive signal and the output to determine at least the volume of the first gas in the gas-containing fluid.

3 more elements

A method of determining at least one property of a gas-containing fluid comprising at least a first gas dissolved in a liquid, the method comprising:

providing a freestanding tube portion supported above a surface of a substrate so as to be capable of vibrating in a plane normal to the surface of the substrate, the freestanding tube portion having a continuous internal passage, a fluid inlet portion of the internal passage through which the gas-containing fluid enters the freestanding tube portion, and a fluid outlet portion of the internal passage through which the gas-containing fluid exits the freestanding tube portion;
flowing the gas-containing fluid through the internal passage of the freestanding tube portion;
generating a drive signal to vibrate the freestanding tube portion at a resonant frequency thereof and avoid alternative vibration modes of the freestanding tube portion, wherein the resonant frequency is proportional to the density of the gas-containing fluid, the Coriolis effect causes the freestanding tube portion to twist about an axis of symmetry thereof while being vibrated at the resonant frequency, and the freestanding tube portion exhibits a degree of twist that varies with the mass flow rate of the gas-containing fluid;
sensing deflections of the freestanding tube portion relative to the substrate and producing an output corresponding to the sensed deflections;
and
assessing the drive signal and the output to determine at least the volume of the first gas in the gas-containing fluid.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 13/270,817Filed 11 Oct 2011 · division
Priority: 27 Dec 2004
Published: US 2012/0260718 A118 Oct 2012
Granted: 2 Apr 2013
Term ends: Not estimatedThe source records don’t support an estimate.

Classification28 codes

G01N 9/002
Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity: using variation of the…
A61M 5/16831
Means for controlling media flow to the body or for metering media to the body, e.g. drip meters, counters: monitoring, detecting, signalling or…
A61M 5/365
With means for eliminating or preventing injection or infusion of air into body: air detectors
A61M 16/08
Devices for influencing the respiratory system of patients by gas treatment, e.g. ventilators ; Tracheal tubes: bellows; Connecting tubes ; Water…

Family

Application60/639,406Us provisional application · filed 27 Dec 2004
Application60/721,220Us provisional application · filed 29 Sep 2005
Application11/306,395Parent of this continuation-in-part · filed 27 Dec 2005
Application61/002,256Us provisional application · filed 8 Nov 2007
Application61/003,089Us provisional application · filed 15 Nov 2007
Application12/267,263Parent of this division · filed 7 Nov 2008
US 2012/0260718 A1Pre-grant publication · published 18 Oct 2012
Application12/267,263Parent of this continuation-in-part
US 2006/0211981 A1Published application
US 2009/0075129 A1Published application
US 8,408,073 B2This patent

From the US filing history. Foreign family members aren’t listed.