An apparatus for in-situ calibration of a photoacoustic sensor includes a measurement device configured to measure an electric signal at an IR emitter of the photoacoustic sensor, wherein the IR emitter generates an electromagnetic spectrum based on the electric signal; and a calibration unit including processing circuitry, configured to compare the electric signal with a comparison value to generate a comparison result used as calibration information. When performing the in-situ calibration, the calibration unit is configured to adjust the electric signal based on the calibration information, or the calibration unit is configured to process an output signal of the photoacoustic sensor based on the calibration information to obtain an adjusted output signal of the photoacoustic sensor.

System and method for measuring a gas concentration are provided. A ball sensor generates a collimated beam of a surface acoustic wave including fundamental wave of first frequency and harmonic wave of second frequency, which propagates through a orbital path on piezoelectric ball while passing through sensitive film to adsorb a target gas. Temperature control unit controls ball temperature of the ball sensor. Signal processing unit transmits a burst signal to sensor electrode of the ball sensor to excite the collimated beam, receives burst signals after the collimated beam has propagated a predetermined number of turns around the piezoelectric ball, and calculates the gas concentration and the ball temperature by first and second relative changes in delay times of the first and second frequencies, respectively, using waveform data of the burst signals.

A photoacoustic detector unit comprises a housing having an opening, and also a photoacoustic transducer designed to convert optical radiation into at least one from a pressure signal or a heat signal. The photoacoustic transducer covers the opening of the housing, such that the photoacoustic transducer and the housing form an acoustically tight cavity. A pressure pick-up is arranged in the acoustically tight cavity.

A system and method for detecting gas sensing employs a waveguide for both electromagnetic and acoustic radiation. Electromagnetic radiation is intensity-modulated and introduced into a waveguide. The waveguide is perforated to admit a gas that absorbs energy at the wavelength of the electromagnetic radiation. An acoustic wave is produced in the waveguide with a frequency equal to the modulation frequency of the electromagnetic radiation. The acoustic wave is received by an acoustic sensor and the presence of the gas is determined in accordance with the received acoustic wave.

The gas-liquid separator comprises: a swirl structure that causes a gas heading from upstream to downstream to swirl about a flow axis heading from upstream to downstream; a separation structure that discharges outward liquid components contained in the gas passing through the swirl structure; and a deflection structure that is provided downstream of the swirl structure and deflects the gas that has passed through the swirl structure. The deflection structure is provided with: a narrowing core portion that has a three-dimensional shape which narrows from upstream to downstream; and deflecting fins that are provided to the side surface of the narrowing core portion and deflect the gas in the opposite direction to the swirling direction resulting from the swirl structure.

The flow regulating structure comprises a plurality of rail structures. Each rail structure has a plurality of rod-shaped members that are arranged side-by-side with the same direction of extension. The plurality of rail structures are disposed along the direction of gas travel in overlapping positions with space therebetween. The extension directions of the rod-shaped members differ between adjacent rail structures. In each rail structure, the plurality of rod-shaped members are arranged side-by-side with the same direction of extension in both a first virtual plane and a second virtual plane, which face one another in the direction of gas travel, and when viewed from the direction of gas travel, the rod-shaped members disposed on the second virtual plane are positioned between adjacent members among the plurality of rod-shaped members disposed on the first virtual plane.

An acoustic analyzer system is provided that includes an acoustic analyzer having a reusable glass flow cell positioned within the acoustic analyzer. A disposable card body may be inserted into the acoustic analyzer and deliver sample fluid to the glass flow cell so that acoustic-wave assisted measurements may be performed on the sample fluid. The disposable card body may also deliver wash fluid to the glass flow cell, and receive waste sample fluid and waste wash fluid from the glass flow cell to prepare the glass flow cell for subsequent sample fluids. Numerous other embodiments are provided.

The invention relates, in a first aspect, to a photoacoustic spectroscope for analyzing gas, comprising an infrared emitter (3), which can be modulated, an analysis volume (1), which can be filled with gas, and a sound pressure detector. The sound pressure detector comprises a structure (5) capable of vibrating, an actuator and a measurement unit, wherein the actuator is configured to actively excite vibration of the structure (5) capable of vibrating and the measurement unit can measure the vibration properties of the structure (5) capable of vibrating, which measurement depends on the formation of the sound pressure waves.

In an additional aspect, the invention relates to a method for analyzing gas, comprising the provision of a photoacoustic spectroscope for analyzing gas, irradiating the gas with infrared radiation, modulated by a modulation frequency, to generate sound pressure waves, exciting the structure (5) capable of vibrating at an excitation frequency, measuring the vibration properties of the structure (5) capable of vibrating, which measurement depends on the sound pressure, and determining the sound pressure of the gas based on the measured vibration properties.

A photo-acoustic gas sensor using a method for modulating the wavelength of the laser radiation, the modulation being obtained via judicious use of an electric current, called the generation current, which pumps the one or more laser sources, and is configured to cause the one or more laser sources to operate in pulsed mode, and of a current, called the base current, which takes non-zero values between each laser pulse with a lower magnitude than the magnitude of the generation current, the magnitude of base current being modulated so that the one or more laser sources emit, into the cell, light radiation having a wavelength that varies periodically about a central wavelength so as to take, at regular intervals, a value specifically suitable for the excitation of a gas to be detected, whereby an interaction between the light radiation and the gas to be detected contained in the cell induces the generation of acoustic waves at a resonant frequency of the cell.

Provided is an apparatus with a gas detection function capable of detecting a detection target gas with high accuracy. An apparatus with a gas detection function comprises: a housing (10); a vibration source (20); and a gas measurement unit (40) located inside the housing and demarcated by a partition, wherein the vibration source is located outside the gas measurement unit, the gas measurement unit includes a detector (41) located on a substrate (30), and a gas detection space (42) provided with a hole (43) through which a gas passes, and a frequency f expressed by the following Formula (1):

[00001]$\begin{array}{cc}f=\frac{c}{2\pi }\sqrt{\frac{S}{\mathrm{VL}}}& \mathrm{Formula}\left(1\right)\end{array}$ is 500 Hz or more, where V is a volume of the gas detection space, S is a cross-sectional area of the hole, L is an effective length of the hole, and c is a sound speed.