Abstract

The purpose of the present invention is to achieve a flow regulating structure that improves the performance of a gas sensor. The flow regulating structure (32) comprises a plurality of rail structures. Each rail structure has a plurality of rod-shaped members (50) 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 (50) differ between adjacent rail structures. In each rail structure, the plurality of rod-shaped members (50) 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 (50) disposed on the second virtual plane are positioned between adjacent members among the plurality of rod-shaped members (50) disposed on the first virtual plane.

IPC Classes  ?

• G01N 29/024 - Analysing fluids by measuring propagation velocity or propagation time of acoustic waves
• G01N 29/32 - Arrangements for suppressing undesired influences, e.g. temperature or pressure variations

Abstract

The purpose of the present invention is to achieve a gas-liquid separator that improves the performance of a gas sensor. The gas-liquid separator (16) 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 (26) that has a three-dimensional shape which narrows from upstream to downstream; and deflecting fins (32) that are provided to the side surface of the narrowing core portion (26) and deflect the gas in the opposite direction to the swirling direction resulting from the swirl structure.

IPC Classes  ?

• B01D 45/12 - Separating dispersed particles from gases or vapours by gravity, inertia, or centrifugal forces by centrifugal forces
• G01N 29/32 - Arrangements for suppressing undesired influences, e.g. temperature or pressure variations

Abstract

The objective of the present invention is to measure gas concentration with a high degree of accuracy. A gas sensor (10) is provided with: a sensor enclosure (14); an ultrasonic transducer (30) provided at one end of the sensor enclosure (14); an ultrasonic wave reflecting surface (44) which is provided at the other end of the sensor enclosure (14) and which intersects an axial direction of the sensor enclosure (14); and a plurality of ventilation holes (16) provided in a side wall of the sensor enclosure (14). The plurality of ventilation holes (16) are provided in positions such that one side of the sensor enclosure (14) cannot be seen from the other side thereof when viewed from a side surface side of the sensor enclosure (14), and each ventilation hole (16) has a shape extending in the axial direction of the sensor enclosure (14).

IPC Classes  ?

• G01N 29/024 - Analysing fluids by measuring propagation velocity or propagation time of acoustic waves
• G01N 29/22 - Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object - Details

Abstract

The purpose of the present invention is to improve the precision of measuring the propagation time of ultrasonic waves. A processor 28 serving as a computation unit is configured to include a correlation object determination unit 32 for establishing: a first to-be-correlated signal established on the basis of a first upper-limit rate of change, which is the rate of change of an upper-limit envelope of a direct wave signal, and a first lower-limit rate of change, which is the rate of change of a lower-limit envelope of the direct wave signal; and a second to-be-correlated signal established on the basis of a second upper-limit rate of change, which is the rate of change of an upper-limit envelope of a round-trip-delayed wave signal, and a second lower-limit rate of change, which is the rate of change of a lower-limit envelope of the round-trip-delayed wave signal. The processor 28 is also configured to include a correlation processing unit 34 for establishing a correlation value between the first to-be-correlated signal and a signal in which the second to-be-correlated signal is moved on a time axis. The correlation processing unit 34 functions as a propagation time measurement unit for establishing the time difference between the first to-be-correlated signal and the second to-be-correlated signal on the basis of the correlation value, and establishing the time for ultrasonic waves to propagate through a concentration measurement space on the basis of the time difference.

IPC Classes  ?

• G01N 29/024 - Analysing fluids by measuring propagation velocity or propagation time of acoustic waves
• G01M 3/24 - Investigating fluid tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using infrasonic, sonic, or ultrasonic vibrations
• G01N 29/50 - Processing the detected response signal using auto-correlation techniques or cross-correlation techniques

Abstract

The purpose of the present invention is to improve the precision of measuring the propagation time of ultrasonic waves. A gas concentration measurement device comprises: a transmission circuit 38 and a transmission oscillator 16 for transmitting first ultrasonic waves in a concentration measurement space and also transmitting second ultrasonic waves, which continue temporally from the first ultrasonic waves in the concentration measurement space; a reception oscillator 18 and a reception circuit 40 for receiving the ultrasonic waves that have propagated through the concentration measurement space; and a propagation time measurement unit 32 for determining, on the basis of the timings at which the first ultrasonic waves and the second ultrasonic waves were transmitted and the timings at which the first ultrasonic waves and the second ultrasonic waves were received, the time in which ultrasonic waves propagate through the concentration measurement space. The second ultrasonic waves have an opposite phase with respect to that of the first ultrasonic waves, and the amplitude of the second ultrasonic waves is greater than that of the first ultrasonic waves.

IPC Classes  ?

• G01N 29/024 - Analysing fluids by measuring propagation velocity or propagation time of acoustic waves
• G01M 3/24 - Investigating fluid tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using infrasonic, sonic, or ultrasonic vibrations
• G01N 29/44 - Processing the detected response signal

Abstract

The objective of the present invention is to improve the measuring accuracy of a gas concentration measuring device. A variable value calculating process includes: a step of measuring a propagation time of the propagation of an ultrasound wave through a measurement sector inside a housing 10; a step of obtaining a temperature calculated value on the basis of the measured value of the propagation time and a reference distance for the measurement sector; a step of obtaining a temperature measured value by measuring the temperature inside the housing 10; and a step of obtaining a temperature replacement fluctuation value indicating a difference between the temperature calculated value and the temperature measured value. The variable value calculating process is executed for each of a plurality of temperature conditions under which the temperature of a reference gas inside the housing 10 differs. A temperature compensation table in which the temperature of a gas to be measured is associated with a temperature compensation value relating to the temperature is obtained on the basis of the temperature replacement fluctuation values obtained under each temperature condition.

IPC Classes  ?

• G01N 29/024 - Analysing fluids by measuring propagation velocity or propagation time of acoustic waves