WO2004010133A1 - 気体濃度計測装置および気体濃度計測方法 - Google Patents
気体濃度計測装置および気体濃度計測方法 Download PDFInfo
- Publication number
- WO2004010133A1 WO2004010133A1 PCT/JP2003/009200 JP0309200W WO2004010133A1 WO 2004010133 A1 WO2004010133 A1 WO 2004010133A1 JP 0309200 W JP0309200 W JP 0309200W WO 2004010133 A1 WO2004010133 A1 WO 2004010133A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- signal
- ultrasonic
- gas concentration
- threshold
- ultrasonic wave
- Prior art date
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Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—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
- G01N29/36—Detecting the response signal, e.g. electronic circuits specially adapted therefor
- G01N29/40—Detecting the response signal, e.g. electronic circuits specially adapted therefor by amplitude filtering, e.g. by applying a threshold or by gain control
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—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
- G01N29/02—Analysing fluids
- G01N29/032—Analysing fluids by measuring attenuation of acoustic waves
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—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
- G01N29/34—Generating the ultrasonic, sonic or infrasonic waves, e.g. electronic circuits specially adapted therefor
- G01N29/341—Generating the ultrasonic, sonic or infrasonic waves, e.g. electronic circuits specially adapted therefor with time characteristics
- G01N29/343—Generating the ultrasonic, sonic or infrasonic waves, e.g. electronic circuits specially adapted therefor with time characteristics pulse waves, e.g. particular sequence of pulses, bursts
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—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
- G01N29/44—Processing the detected response signal, e.g. electronic circuits specially adapted therefor
- G01N29/48—Processing the detected response signal, e.g. electronic circuits specially adapted therefor by amplitude comparison
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/02—Indexing codes associated with the analysed material
- G01N2291/021—Gases
- G01N2291/0212—Binary gases
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/02—Indexing codes associated with the analysed material
- G01N2291/028—Material parameters
- G01N2291/02809—Concentration of a compound, e.g. measured by a surface mass change
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/02—Indexing codes associated with the analysed material
- G01N2291/028—Material parameters
- G01N2291/02818—Density, viscosity
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/02—Indexing codes associated with the analysed material
- G01N2291/028—Material parameters
- G01N2291/02836—Flow rate, liquid level
Definitions
- the present invention relates to a gas concentration measuring device and a gas concentration measuring method for measuring a change in gas concentration in a measurement target area.
- methods for measuring changes in gas concentration and flow rate include the dielectric relaxation method, which measures the permittivity of a substance, the absorption spectrum measurement method, which measures the absorption distribution of electromagnetic waves, and passing There is the “ultrasonic wave propagation wave attenuation measurement method” that measures the attenuation rate of the amplitude of the ultrasonic wave obtained. Neither method has high temporal resolution o
- the propagation time difference method for measuring the propagation time of a sound wave from a transmitter to a receiver is a simple method, and also leads to an improvement in time resolution.
- a stationary wave such as a sine wave is transmitted from the transmitter and received by the receiver, and the source standing wave (transmitted wave) is compared with the signal (received wave) from the receiver.
- the wave peak shift (phase difference) is defined as the propagation time, and the propagation time corresponds to changes in gas concentration and flow rate. Disclosure of the invention
- a gas concentration measuring device that solves the above problem by using a rectangular pulse wave instead of a standing wave has been developed.
- an ultrasonic wave generated based on the rectangular pulse wave is first received by an ultrasonic receiver on the receiving side.
- the time difference between the time when a specified number of waves from the beginning exceed the threshold voltage and the time when the first signal of the rectangular pulse wave is output is calculated.
- the time difference is output as gas concentration change and flow rate change in the measurement target area.
- the above measurement point is located in the time zone immediately after the ultrasonic receiving element receives a sound wave and starts to vibrate. During this time zone, the operation of the ultrasonic receiving element is still unstable, and the measurement results Was unstable. For this reason, conventionally, a large number of measurements and their averaging were performed to obtain a representative value, which took a long time to measure and complicated the measurement work.
- the present invention has been proposed in view of the above, and it is possible to measure a change in gas concentration and the like even when the distance between an ultrasonic transmitting unit and a receiving unit is less than 1 cm, and a single measurement can be performed. It is an object of the present invention to provide a gas concentration measuring device and a gas concentration measuring method capable of obtaining a highly accurate and stable measurement result only by using the gas concentration measuring device.
- the invention described in claim 1 is a gas concentration measuring device that measures a change in the concentration of gas in a measurement target area
- the gas pulse measuring device includes a rectangular pulse wave group including a plurality of rectangular pulse waves.
- An ultrasonic transmission means for transmitting an ultrasonic wave in accordance with the ultrasonic generation signal as an ultrasonic generation signal, and converting the ultrasonic wave after passing through the gas in the measurement target region into an electric signal and receiving an ultrasonic reception signal
- An ultrasonic receiving means for detecting the signal output time of the ultrasonic generation signal, and performing an envelope extraction process on the ultrasonic reception signal to obtain an envelope processing signal;
- Gas concentration measuring means for determining a threshold falling time point at which the threshold value becomes equal to or less than the threshold value after exceeding the threshold value, and detecting a difference between the threshold falling time point and the signal output time point as a change in gas concentration. It is characterized in that
- the invention described in claim 3 is a gas concentration measurement method for measuring a change in gas concentration in a measurement target area, wherein a group of rectangular pulse waves including a plurality of rectangular pulse waves is used as an ultrasonic wave generation signal, An ultrasonic wave is transmitted in accordance with the ultrasonic generation signal, and the ultrasonic wave after passing through the gas in the measurement target area is converted into an electric signal to be an ultrasonic reception signal, and a signal output time point of the ultrasonic generation signal On the other hand, an envelope processing is performed on the ultrasonic reception signal to obtain an envelope processing signal.
- a threshold falling time point at which the envelope processing signal falls below the predetermined threshold value after exceeding the predetermined threshold value is obtained, and a difference between the threshold falling time point and the signal output time point is detected as a change in gas concentration.
- FIG. 1 is a block diagram of a gas concentration measuring device of the present invention.
- FIG. 2 is a diagram showing a configuration example of a main part around a measurement target area.
- FIG. 3 is a circuit diagram showing an ultrasonic pulse generator of the gas concentration measuring device.
- FIG. 4 is a circuit diagram showing an ultrasonic pulse receiving unit of the gas concentration measuring device.
- FIG. 5 is a circuit diagram showing a time difference measuring unit of the gas concentration measuring device.
- FIG. 6 is a diagram showing a signal waveform at a predetermined portion of the gas concentration measuring device.
- FIG. 7 is a diagram showing a configuration example of a gas switching device.
- FIG. 8 is a diagram showing the results of switching the gas in the T measurement target area using the gas switching device of FIG. 7 and measuring the change in concentration with the gas concentration measuring device of the present invention.
- FIG. 9 is a diagram showing a result of switching a gas in a measurement target region using the gas switching device of FIG. 7 and measuring a change in the mixture ratio by the gas concentration measuring device of the present invention.
- FIG. 1 is a block diagram of a gas concentration measuring device of the present invention.
- a gas concentration measuring device 1 of the present invention is a gas concentration measuring device 1 for measuring a change in the gas concentration in a measurement target region R.
- the ultrasonic transmission means 2 transmits ultrasonic waves in accordance with the ultrasonic generation signal S 1 and the ultrasonic waves after passing through the gas in the measurement target area R are converted into electric signals to receive ultrasonic waves.
- the ultrasonic receiving means 3 as the signal S 2 and the signal output time point st of the ultrasonic generation signal S 1 are detected, and the envelope receiving processing is performed on the ultrasonic receiving signal S 2 to obtain an envelope processing signal.
- the envelope processing A gas concentration measuring means for obtaining a threshold falling time point sd, which is a time point when a signal exceeds a predetermined threshold value and falls below the threshold value, and detects a difference between the threshold falling time point and a signal output time point st as a change in gas concentration. 4 and.
- FIG. 2 is a diagram showing a configuration example of a main part around a measurement target area.
- the ultrasonic transmitting means 2 and the ultrasonic receiving means 3 each include an ultrasonic transmitting element 21 and an ultrasonic receiving element 31 each formed of, for example, a piezoelectric element.
- 21 transmits an ultrasonic wave of, for example, 400 kHz in response to the ultrasonic wave generation signal S1.
- this ultrasonic wave is received by the ultrasonic receiving element 31, converted into an electric signal, and output as an ultrasonic receiving signal S 2.
- FIG. 3 is a circuit diagram showing the ultrasonic pulse generator of the gas concentration measuring device
- Fig. 4 is a circuit diagram showing the ultrasonic pulse receiving unit of the gas concentration measuring device
- Fig. 5 is the time difference measurement of the gas concentration measuring device.
- FIG. 6 is a circuit diagram showing a portion
- FIG. 6 is a diagram showing a signal waveform at a predetermined portion of the gas concentration measuring device.
- the gas concentration measuring device 1 of the present invention when generating ultrasonic waves, a plurality of (for example, several to approximately Hi) rectangular pulse waves having a predetermined period as shown in FIG. Rectangular wave group S1 is used.
- the rectangular pulse wave group (ultrasonic wave generation signal) S 1 is generated by the ultrasonic wave pulse generator 20 shown in FIG. 3, and is input to the ultrasonic wave transmitting element 21 at the final stage. An ultrasonic wave is output according to the vibration of 21. Then, the ultrasonic generation signal S 1 branched off from the signal line between the ultrasonic pulse generator 20 (the 55 5) and the frequency divider in the ultrasonic pulse generator 20 is converted to the time difference measurement unit shown in FIG. Output to 6.
- the ultrasonic wave that has passed through the measurement target region R and is affected by the gas is received by the ultrasonic receiving element 31 of the ultrasonic pulse receiving unit 5 in FIG. 4 and is converted into an electric signal.
- An ultrasonic reception signal S2 as shown in (b) is obtained.
- the ultrasonic pulse receiving unit 5 then performs an envelope extraction process on the ultrasonic reception signal S2 using a low-pass filter, and obtains an envelope as shown in FIG. 6 (c). And generates a short-circuit processing signal S3.
- the comparison between the envelope processing signal S 3 and the threshold voltage E 0 is performed using a comparator, and when the envelope processing signal S 3 exceeds the threshold voltage E 0, and then falls and drops below the threshold voltage E 0. Is detected as the threshold falling time sd, and the threshold falling time sd is output to the time difference measuring unit 6.
- the time difference measurement unit 6 obtains the first signal output time point st of the ultrasonic generation signal S1. Then, a time difference between the threshold drop time sd and the signal output time st is obtained, and this time difference is output as a change in the gas concentration.
- the ultrasonic transmitting unit 2 corresponds to the ultrasonic pulse generating unit 20
- the ultrasonic receiving unit 3 corresponds to the ultrasonic pulse receiving unit 5.
- the gas concentration measuring means 4 corresponds to the ultrasonic pulse generating section 20 and the time difference measuring section 6 downstream of the ultrasonic receiving element 31.
- the gas concentration measuring device 1 of the invention was to obtain the first time difference between the signal output point st threshold value drops when s d and ultrasonic generation signals S 1 envelope processing signal S 3.
- This time difference is a value corresponding to the gas concentration change and the gas flow rate change in the measurement target area R, and by calculating this time difference, the gas concentration change and the gas flow rate change in the measurement target area R can be accurately determined. You can ask.
- the threshold drop time sd is located in a region where the ultrasonic reception signal S2 is attenuated and stable, so that the measurement result is also stable.Therefore, in order to maintain the accuracy of the data conventionally, This eliminates the need for processing such as averaging, which is necessary for the measurement, and enables the measurement of changes in gas concentration in a single transmission and reception of ultrasonic waves. It is now possible to promptly ask for it.
- the ultrasonic waves are generated using the rectangular pulse wave, the secondary and tertiary reflections, which were conventionally generated when the standing wave was used, are not generated. Even if the distance between the ultrasonic wave transmitting element 21 and the ultrasonic receiving element 31 is shortened to about several mm, measurement becomes possible, and changes in gas concentration and gas flow rate in the thin tube can be measured with high accuracy. It became so. Conventionally, when the predetermined number of waves from the beginning exceeds the threshold voltage (point A in Fig. 6 (b)), the envelope extraction processing is performed on the ultrasonic reception signal S2.
- the time when the threshold voltage is exceeded is set as the sound wave arrival time, the time difference between the sound wave arrival time and the signal output time st is calculated, and the time difference is used as the gas concentration change and flow rate change in the measurement target region R Output.
- the vicinity of the point at which the ultrasonic receiving element 31 receives a sound wave and starts to vibrate (around point A in FIG. 2) is unstable. This is being dealt with using the algorithm.
- the measurement result is still unstable. Therefore, the average value is measured multiple times and the average value is used. In other words, a stable signal was obtained at the expense of time resolution.
- the inventor of the present invention has concluded that the first half of the ultrasonic receiving element 31 which starts receiving sound waves is unstable as mentioned above, ) was found to be very stable (blurring is unlikely to occur under the same experiment), and the latter half of this stable measurement was used for measurement. Therefore, in the present invention, the envelope of the received wave is first extracted by using the low-pass filter, and the time sd at which the envelope falls rather than rising is detected. That is, instead of calculating the time point when the voltage exceeds the threshold voltage E 0, the time when the voltage falls below the threshold voltage E 0 was calculated. As a result, it is possible to measure changes in gas concentration and flow rate by transmitting and receiving ultrasonic waves once without performing processing such as averaging.
- Fig. 2 shows a configuration example of a gas switching device. It is a figure showing a result.
- both air and nitrogen can always flow into the measurement target area R, and the switching unit R1 is connected to, for example, the air side, and when the air is sucked from the switching unit R1, Only nitrogen flows through the measurement target region R. Then, the gas concentration measurement device 1 transmits ultrasonic waves from the ultrasonic transmission element 21 and passes the gas in the measurement target region R, thereby measuring a change in the gas concentration.
- the measurement of the present invention measures the molecular weights of nitrogen and air having a molecular weight of 28 and 28, which are close to each other, and has a higher SZN ratio than the conventional one even though it is a single measurement. Has been realized.
- FIG. 9 shows the results of measuring the time difference between the threshold drop time sd and the signal output time st when the air) was changed to 25%.
- the time difference is measured by detecting the threshold falling time point sd located in the latter half of the ultrasonic reception signal S2, so that the measurement is performed with high accuracy and high speed. It is performed stably and, as a result, as can be seen from Fig. 9, the time difference linearly responds to the gas mixture ratio (composition ratio).
- the present invention which is capable of high-accuracy, high-speed, and stable measurement of gas concentration changes, enables high-resolution measurement of changes in fluids such as chemical plants and engines. Become. In the above description, the case where air and nitrogen or oxygen and nitrogen flow alternately in the measurement target region R has been described. However, this gas is not limited to air and nitrogen, and any gas may be used. can do. Industrial applicability
- the time difference between the time point when the threshold value of the envelope processing signal falls and the time point when the signal of the ultrasonic wave generation signal is output is determined.
- the measurement result is stable because it is located in the area where the signal is being transmitted, so that processing such as averaging, which was conventionally required to maintain data accuracy, is no longer necessary, and the transmission of one ultrasonic wave ⁇ It is possible to measure the change in concentration in gas by receiving. Therefore, the measurement of the gas concentration change can be obtained promptly in a short time.
- the ultrasonic wave is generated using the rectangular pulse wave, the secondary and tertiary reflections that were generated when the conventional standing wave was used are not generated. Even if the distance between the sensor and the ultrasonic receiving element is reduced to about several mm, measurement can be performed, and changes in gas concentration and gas flow rate in the thin tube can be measured with high accuracy.
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Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/521,746 US7201034B2 (en) | 2002-07-19 | 2003-07-18 | Gas concentration measurement instrument and gas concentration measurement method |
EP03765333A EP1542003B1 (en) | 2002-07-19 | 2003-07-18 | Gas concentration measurement instrument and gas concentration measurement method |
AU2003252224A AU2003252224A1 (en) | 2002-07-19 | 2003-07-18 | Gas concentration measurement instrument and gas concentration measurement method |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2002-210512 | 2002-07-19 | ||
JP2002210512A JP3700000B2 (ja) | 2002-07-19 | 2002-07-19 | 気体濃度計測装置および気体濃度計測方法 |
Publications (1)
Publication Number | Publication Date |
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WO2004010133A1 true WO2004010133A1 (ja) | 2004-01-29 |
Family
ID=30767734
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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PCT/JP2003/009200 WO2004010133A1 (ja) | 2002-07-19 | 2003-07-18 | 気体濃度計測装置および気体濃度計測方法 |
Country Status (5)
Country | Link |
---|---|
US (1) | US7201034B2 (ja) |
EP (1) | EP1542003B1 (ja) |
JP (1) | JP3700000B2 (ja) |
AU (1) | AU2003252224A1 (ja) |
WO (1) | WO2004010133A1 (ja) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
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KR100583556B1 (ko) | 2005-12-05 | 2006-05-26 | 웨스글로벌 주식회사 | 포락선 신호를 이용한 농도계측장치 및 방법 |
US20160023770A1 (en) * | 2014-07-25 | 2016-01-28 | Nathan Thompson | Air heating apparatus useful for heating an aircraft interior |
DE102015222583A1 (de) * | 2015-11-16 | 2017-05-18 | Robert Bosch Gmbh | Überwachungsverfahren und Überwachungssystem für Brenngas |
JP6909697B2 (ja) * | 2017-10-04 | 2021-07-28 | 上田日本無線株式会社 | 伝搬時間測定器、気体濃度測定装置、および伝搬時間測定プログラム |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH08136651A (ja) * | 1994-11-14 | 1996-05-31 | Suzuki Motor Corp | 超音波距離測定装置 |
JP2002005900A (ja) * | 2000-06-20 | 2002-01-09 | Ngk Spark Plug Co Ltd | ガス濃度センサ |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4520654A (en) * | 1983-03-14 | 1985-06-04 | General Electric Company | Method and apparatus for detecting hydrogen, oxygen and water vapor concentrations in a host gas |
JPS63163161A (ja) * | 1986-12-25 | 1988-07-06 | Calsonic Corp | オイル状態検知装置 |
JP2891767B2 (ja) * | 1989-10-25 | 1999-05-17 | 日本たばこ産業株式会社 | Ae発生位置標定装置 |
JPH0658751A (ja) * | 1992-06-09 | 1994-03-04 | Nkk Corp | 超音波信号処理装置及び超音波厚み計 |
JP3130223B2 (ja) * | 1994-11-18 | 2001-01-31 | 三菱電機株式会社 | 検出方法及び検出装置 |
FR2739185B1 (fr) * | 1995-09-25 | 1997-11-14 | Schlumberger Ind Sa | Procede de mesure acoustique d'un debit de fluide |
JP2002520584A (ja) * | 1998-07-10 | 2002-07-09 | パナメトリクス・インコーポレイテッド | 誘導モードによる流量測定システム |
JP2002005901A (ja) * | 2000-06-21 | 2002-01-09 | Ngk Spark Plug Co Ltd | ガスセンサ、ガス濃度及び流量測定方法 |
-
2002
- 2002-07-19 JP JP2002210512A patent/JP3700000B2/ja not_active Expired - Lifetime
-
2003
- 2003-07-18 WO PCT/JP2003/009200 patent/WO2004010133A1/ja active Application Filing
- 2003-07-18 AU AU2003252224A patent/AU2003252224A1/en not_active Abandoned
- 2003-07-18 US US10/521,746 patent/US7201034B2/en not_active Expired - Fee Related
- 2003-07-18 EP EP03765333A patent/EP1542003B1/en not_active Expired - Fee Related
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH08136651A (ja) * | 1994-11-14 | 1996-05-31 | Suzuki Motor Corp | 超音波距離測定装置 |
JP2002005900A (ja) * | 2000-06-20 | 2002-01-09 | Ngk Spark Plug Co Ltd | ガス濃度センサ |
Non-Patent Citations (1)
Title |
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See also references of EP1542003A4 * |
Also Published As
Publication number | Publication date |
---|---|
EP1542003A4 (en) | 2008-11-19 |
EP1542003A1 (en) | 2005-06-15 |
JP2004053385A (ja) | 2004-02-19 |
JP3700000B2 (ja) | 2005-09-28 |
US7201034B2 (en) | 2007-04-10 |
AU2003252224A1 (en) | 2004-02-09 |
US20050235734A1 (en) | 2005-10-27 |
EP1542003B1 (en) | 2011-10-19 |
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