System and method for analyzing a gas

Patent metadata

Field	Value
Publication number	US-10175212-B2
Application number	US-201414558219-A
Country	US
Kind code	B2
Filing date	Dec 2, 2014
Priority date	Dec 2, 2013
Publication date	Jan 8, 2019
Grant date	Jan 8, 2019

Abstract

A gas analysis system includes a fluidic channel for flow of a gas to be analyzed, a detector in the channel and adapted for measuring interactions of the gas with the detector, the detector including a resonator of the electromechanical nanosystem (NEMS) type and a heating system for heating a part of the detector, an actuation device for vibrationally actuating the resonator according to an excitation signal applied to an input of the detector, a detection device adapted for providing an output electric signal representative of the vibrations of the resonator, a read-out device connected to an input of the detector and configured for simultaneously measuring, from the output signal of the detector, the change in resonance frequency and the change in amplitude of the vibrations at the resonance frequency of the resonator, and a processing device configured for determining from the changes a fluidic characteristic of the gas.

First claim

The invention claimed is:

1. A gas analysis system comprising:
a fluidic channel intended for the flow of a gas to be analyzed,
at least one detector laid out in said fluidic channel and adapted for measuring interactions of the gas with said detector, said detector comprising at least one resonator of the electromechanical nanosystem (NEMS) type,
an actuation device for vibrationally actuating the resonator according to an excitation signal applied to an input of the detector, and
a detection device adapted for providing an output electric signal representative of the vibrations of said resonator,
a read-out device connected to an input of the detector and configured for simultaneously measuring, from the output signal of said at least one detector, the change in resonance frequency and the change in amplitude of the vibrations at the resonance frequency of the resonator, and
a processing device configured for determining from said changes at least one of a viscosity and an effective viscosity of said gas,
wherein the at least one detector comprises an electrical heating system operable for heating at least a part of the resonator or the detection device by Joule effect.

2. The system of claim 1 , comprising a plurality of detectors electrically connected in parallel so as to form at least one network having:
at least one input for applying, with the read-out device, at least one excitation signal in vibration, to the whole of the detectors of the network, and
at least one output for providing a signal resulting from the output signals of each of the detectors of the network.

3. The system of claim 2 , wherein said resulting signal includes the different output signals of the detectors connected in parallel and the processing device is configured for calculating an average of the output signal of the detectors of the network.

4. The system of claim 2 , wherein said fluidic channel locally has a restriction and/or a widening of its cross-section and the system comprises detectors or networks of detectors laid out in portions of the fluidic channel having different cross-sections.

5. The system of claim 1 , further comprising a chromatography column, the fluidic channel being laid out in at least a downstream portion of the chromatography column relatively to the direction of flow of the gas and at least a portion of said detectors or network of detectors being in said column.

6. The system of claim 1 , comprising at least two detectors or networks of detectors, the resonators of which are functionalized with different chemical species.

7. The system of claim 1 , wherein at least two detectors of a same network of two detectors of networks of distinct detectors have at least one different geometrical characteristic.

8. The system of claim 7 , wherein said at least one different geometrical characteristic of a detector is selected from: the thickness of at least one resonator, the length of at least one resonator, the width of at least one resonator, the distance between at least one resonator and the actuation device.

9. The system of claim 1 , further comprising a vacuum pump downstream from said fluidic channel.

10. The system of claim 1 , wherein said processing device is further configured for applying an algorithm with which the frequency and amplitude variation measurements may be merged.

11. The system of claim 1 , wherein the read-out device comprises a phase locked loop (PLL).

12. The system of claim 1 , wherein the read-out device comprises an oscillator.

13. The system of claim 1 , wherein the read-out device is configured, for a selected resonance mode of the detector, for measuring the resonance frequency on said selected resonance mode of the detector and optionally for measuring the amplitude of the vibrations on at least one higher resonance mode than said selected mode.

14. The system of claim 1 , wherein the resonator is a beam clamped at one of its ends and free at the opposite end and wherein the detection device comprises two piezo-resistive strain gauges laid out on either side of said beam in the vicinity of the clamped end, the heating system being configured to heat the strain gauges by Joule effect.

15. The system of claim 1 , wherein the resonator is a beam clamped at both ends, the heating system being configured to heat the beam by Joule effect.

16. The system of claim 1 , comprising at least one detector or network of detectors, each resonator of which is functionalized with a porous layer.

17. A method for analyzing a gas, wherein:
a gas to be analyzed is injected into a gas analysis system comprising:
a fluidic channel intended for the flow of a gas to be analyzed, wherein the gas is carried by a carrier gas,
at least one detector laid out in said fluidic channel and adapted for measuring interactions of the gas with said detector, said detector comprising at least one resonator of the electromechanical nanosystem (NEMS) type,
an actuation device for vibrationally actuating the resonator according to an excitation signal applied to an input of the detector, and
a detection device adapted for providing an output electric signal representative of the vibrations of said resonator,
an electrical heating system operable for heating at least a part of the resonator or the detection device by Joule effect,
a read-out device connected to an input of the detector and configured for simultaneously measuring, from the output signal of said at least one detector, the change in resonance frequency and the change in amplitude of the vibrations at the resonance frequency of the resonator, and
a processing device configured for determining from said changes at least one of a viscosity and an effective viscosity of said gas,
the heating system is operated to increase a viscosity contrast between the gas to be analyzed and the carrier gas in a vicinity of the heated part of the resonator or detection device,
at least one resonator of a detector or network of detectors of said system is actuated for causing vibration of said resonator at a resonance frequency,
an output signal representative of the vibration of the resonator or of the whole of the resonators of said detector or network of detectors is read out, and
the resonance frequency and the amplitude of the vibrations at the resonance frequency of each detector are measured from the output signal simultaneously, and
a viscosity and an effective viscosity of the gas is determined from changes in said resonance frequency and amplitude.

18. The method of claim 17 , wherein a depression is formed in the fluidic channel in which is laid out said at least one detector or network of detectors.

19. The method of claim 17 , wherein the gas to be analyzed is injected into the system with a carrier gas and wherein said carrier gas is selected so that it has at least one fluidic characteristic different from that of the gas to be analyzed.

20. The method of claim 19 , wherein the gas is heated upstream from the detector or from the network of detectors and/or said detector or network of detectors is heated so as to increase the contrast between said different fluidic characteristic of the carrier gas and that of the gas to be analyzed.

21. The method of claim 17 , wherein a merging algorithm is applied with which the frequency and amplitude variation measurements may be merged.

22. A method for analyzing a gas, wherein:
a gas to be analyzed is injected into a gas analysis system comprising:
a fluidi

Assignees

• California Inst Of Techn
• Commissariat Energie Atomique
• Apix Analytics

Inventors

• Andreucci Philippe
• Colinet Eric
• Duraffourg Laurent
• Myers Edward
• Petitjean Mélanie
• Roukes Mickael Lee
• Whiting Joshua

Classifications

• G01N29/022

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• G01N2291/106

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• B82Y15/00

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