Photoacoustic detection system with clocked tuning fork positions

Patent metadata

Field	Value
Publication number	US-11754533-B2
Application number	US-201917053864-A
Country	US
Kind code	B2
Filing date	May 8, 2019
Priority date	May 11, 2018
Publication date	Sep 12, 2023
Grant date	Sep 12, 2023

Abstract

A photoacoustic detection system (20) includes a detector (22) that has a chamber (24), a pulsed light source (26), piezoelectric tuning forks (28), and a photosensor (30). The chamber has an inlet and an outlet for flow of an analyte. The pulsed light source is adjacent the chamber and is operable to emit a light beam along a path through the chamber. The tuning forks are arranged along the path, and each of the tuning forks is operable to emit first sensor signals. The photosensor is arranged along the path and is operable to emit second sensor signals. A controller (38) is connected to receive the first and second sensor signals. The controller is configured to determine whether a target species is present in the analyte based on the first sensor signals and determine whether the target species is present in the analyte based on the second sensor signals.

First claim

What is claimed is:

1. A photoacoustic detection system comprising:
a detector including,
a pulsed light source operable to emit a light beam along a path,
a plurality of piezoelectric tuning forks arranged side-by-side so as to form a resonance cavity along the path, each of the piezoelectric tuning forks having a respective unique resonant frequency, and each of the piezoelectric tuning forks operable to emit sensor signals indicative of a photoacoustic response of an analyte to interaction of the analyte with the light beam; and

a controller connected to receive the sensor signals,
wherein the path defines a central axis and each of the piezoelectric tuning forks having first and second tines that straddle the central axis, and
wherein each of the piezoelectric tuning forks has an opening defined between tips of the first and second tines, and each opening is oriented at a different clocked position about the central axis without a continuous gap between the openings.

2. The system as recited in claim 1 , wherein the first and second tines include gold and quartz.

3. The system as recited in claim 1 , wherein the controller is configured to determine whether a target species is present in the analyte based on an intensity of the photoacoustic response.

4. The system as recited in claim 1 , wherein the controller is configured to determine an identity of a target species that is present in the analyte based on a spectrum of the photoacoustic response across the piezoelectric tuning forks.

5. The system as recited in claim 1 , wherein the unique resonant frequencies fall within a range of 4 kHz between a largest one of the unique resonant frequencies frequency and a smallest one of the unique resonant frequencies.

6. A photoacoustic detection system comprising:
a series of piezoelectric tuning forks arranged side-by-side along an axis, each of the piezoelectric tuning forks having a unique resonant frequency and each of the piezoelectric tuning forks having first and second tines that straddle the axis so as to form a resonance cavity,
wherein each of the piezoelectric tuning forks has an opening defined between tips of the first and second tines, and each opening is oriented at a different clocked position about the central axis without a continuous gap between the openings.

7. The system as recited in claim 6 , wherein the unique resonant frequencies fall within a range of 4 kHz between a largest one of the unique resonant frequencies frequency and a smallest one of the unique resonant frequencies.

Assignees

• Carrier Corp

Inventors

• Lincoln David L
• Birnkrant Michael J
• Harris Peter R
• Piech Marcin
• Blanc Arthur
• Castillo-Garza Jose-Rodrigo

Classifications

• G01N21/1702 Primary

  with opto-acoustic detection, e.g. for gases or analysing solids · CPC title

• G01N29/2425 Primary

  optoacoustic fluid cells therefor · CPC title

• G01N21/3504

  for analysing gases, e.g. multi-gas analysis · CPC title

• G01N29/022

  Fluid sensors based on microsensors, e.g. quartz crystal-microbalance [QCM], surface acoustic wave [SAW] devices, tuning forks, cantilevers, flexural plate wave [FPW] devices (microdevices per se B81B) · CPC title

• G01N29/2418

  using optoacoustic interaction with the material, e.g. laser radiation, photoacoustics (photoacoustic cells G01N21/1702; measuring characteristics of vibrations by using radiation-sensitive means G01H9/00; acousto-optical conversion techniques for short-range imaging G01S15/8965; sound-producing devices using laser bundle G10K15/046) · CPC title