JP2010256075A - Flowmeter and method of measuring flow rate - Google Patents

Flowmeter and method of measuring flow rate Download PDF

Info

Publication number
JP2010256075A
JP2010256075A JP2009103998A JP2009103998A JP2010256075A JP 2010256075 A JP2010256075 A JP 2010256075A JP 2009103998 A JP2009103998 A JP 2009103998A JP 2009103998 A JP2009103998 A JP 2009103998A JP 2010256075 A JP2010256075 A JP 2010256075A
Authority
JP
Japan
Prior art keywords
standard
temperature
flow rate
actual
ultrasonic
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP2009103998A
Other languages
Japanese (ja)
Inventor
Yutaka Tanaka
豊 田中
Yojiro Sugiura
洋次郎 杉浦
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Aichi Tokei Denki Co Ltd
Original Assignee
Aichi Tokei Denki Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Aichi Tokei Denki Co Ltd filed Critical Aichi Tokei Denki Co Ltd
Priority to JP2009103998A priority Critical patent/JP2010256075A/en
Publication of JP2010256075A publication Critical patent/JP2010256075A/en
Pending legal-status Critical Current

Links

Images

Landscapes

  • Measuring Volume Flow (AREA)
  • Details Of Flowmeters (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flowmeter for stably measuring a standard flow rate, etc. and a method of measuring a flow rate. <P>SOLUTION: An ultrasonic flowmeter 10 measures a flow velocity V and temperature T1 of a gas in a measuring tube 13 by using first and second ultrasonic transmitter-receivers 14 and 15 while measuring hydrostatic pressure P1 of the gas in the measuring tube 13 by using a static pressure meter 17. A dynamic pressure P2 of the gas is calculated from the flow velocity V while a total pressure P3 is calculated by using the sum of the hydrostatic pressure P1 and the dynamic pressure P2. By using the measured or calculated actual total pressure P3, actual temperature T1, and actual total pressure P3, and a relational expression based on the Boyle-Charle's law, the actual flow velocity V is output by calculating a standard unit flow rate Qx and the standard flow rate Q. The flow rate Qx is of the gas flowing through a unit area in the measuring tube 13 at previously determined standard temperature T0 and standard total pressure P0. The flow rate Q is found by multiplying the flow rate Qx by the inside cross-section of the measuring tube 13. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

本発明は、計測管内を任意の温度及び圧力で流れる気体の流速を、ボイル・シャルルの法則に基づく関係式を使用して、予め定めた標準温度及び標準圧力で流れる標準流量等に変換して計測する流量計及び流量計測方法に関する。   The present invention converts the flow velocity of a gas flowing through a measuring tube at an arbitrary temperature and pressure into a standard flow rate flowing at a predetermined standard temperature and pressure using a relational expression based on Boyle-Charles' law. The present invention relates to a flow meter to measure and a flow measurement method.

従来、この種の流量計として、温度センサー及び圧力センサーにて検出した温度及び圧力と流量計本体にて計測した流速とをボイル・シャルルの法則に基づく関係式に代入して標準流量に演算するものが知られている(例えば、特許文献1参照)。   Conventionally, as this type of flow meter, the temperature and pressure detected by the temperature sensor and the pressure sensor and the flow velocity measured by the flow meter body are substituted into the relational expression based on Boyle-Charles' law, and the standard flow rate is calculated. Those are known (for example, see Patent Document 1).

特開2007−187506号公報(段落[0003])JP 2007-187506 A (paragraph [0003])

ところが、上述した従来の流量計を、例えば都市ガスの配管網の複数位置に取り付けると、ガス供給元で検出した標準流量と配管網の末端部分の複数位置で検出した標準流量との総和にずれが生じる場合があった。即ち、上述した従来の流量計では、標準流量が正確に計測できていなかった。   However, if the conventional flowmeters described above are attached to, for example, a plurality of positions in a city gas piping network, the sum of a standard flow rate detected at a gas supply source and a standard flow rate detected at a plurality of positions at the end of the piping network is shifted. May occur. That is, the conventional flow meter described above cannot accurately measure the standard flow rate.

本発明は、上記事情に鑑みてなされたもので、標準流量等を安定して正確に計測可能な流量計及び流量計測方法の提供を目的とする。   The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a flow meter and a flow rate measuring method capable of measuring a standard flow rate stably and accurately.

従来の流量計の計測誤差を解析したところ流速が増すに従って計測誤差が大きくなることが判明した。この点から、流速の影響を考慮した演算を行って標準流量等を計測する以下の発明を完成するに至った。   Analysis of the measurement error of a conventional flow meter revealed that the measurement error increased as the flow velocity increased. From this point, the following invention for measuring the standard flow rate and the like by performing calculation in consideration of the influence of the flow velocity has been completed.

請求項1の発明は、計測管内の気体の流速を検出可能な流速検出部と、計測管内の気体の静圧を検出可能な静圧検出部と、流速から気体の動圧を演算する動圧演算部と、静圧及び動圧の和で全圧を演算する全圧演算部と、計測管内の気体の温度を検出可能な温度検出部と、流速検出部、温度検出部及び全圧演算部にて検出した実際の流速、実際の温度及び実際の全圧と、ボイル・シャルルの法則に基づく関係式とを使用して、実際の流速を、予め定めた標準温度及び標準全圧で計測管内の単位面積に流れる気体の標準単位流量に変換するか、又は、標準単位流量に計測管の内側断面積を乗じた標準流量に変換する標準変換部とを備えたことを特徴とする流量計である。   The invention of claim 1 is a flow rate detection unit capable of detecting a flow rate of gas in a measurement tube, a static pressure detection unit capable of detecting a static pressure of gas in the measurement tube, and a dynamic pressure for calculating the dynamic pressure of the gas from the flow rate. A calculation unit, a total pressure calculation unit that calculates the total pressure by the sum of static pressure and dynamic pressure, a temperature detection unit that can detect the temperature of the gas in the measurement tube, a flow rate detection unit, a temperature detection unit, and a total pressure calculation unit Using the actual flow velocity, actual temperature, and actual total pressure detected in Step 1, and the relational expression based on Boyle-Charles' law, the actual flow velocity is measured at a predetermined standard temperature and standard total pressure. A flow meter characterized by comprising a standard conversion unit for converting to a standard unit flow rate of gas flowing in a unit area or converting to a standard flow rate obtained by multiplying the standard unit flow rate by the inner cross-sectional area of the measuring tube. is there.

請求項2の発明は、標準温度をT0、標準全圧をP0、標準温度T0及び標準全圧P0下の気体の密度である標準密度をρ0、実際の温度をT1、静圧をP1、動圧をP2、実際の温度T1及び実際の全圧下の気体の密度である計測時密度をρ1、実際の流速をVとすると、動圧演算部は、下記式(1),(2)に基づいて計測時密度ρ1及び動圧P2を演算することを特徴とする請求項1に記載の流量計である。   In the invention of claim 2, the standard temperature is T0, the standard total pressure is P0, the standard temperature which is the density of the gas under the standard temperature T0 and the standard total pressure P0 is ρ0, the actual temperature is T1, the static pressure is P1, Assuming that the pressure is P2, the actual temperature T1 and the measured density which is the density of the gas under the actual total pressure is ρ1, and the actual flow velocity is V, the dynamic pressure calculation unit is based on the following equations (1) and (2). The flowmeter according to claim 1, wherein the density during measurement ρ1 and the dynamic pressure P2 are calculated.

Figure 2010256075
Figure 2010256075

請求項3の発明は、流速検出部は、計測管の軸方向の異なる2位置に配置され、双方向で超音波を送受波可能な第1と第2の超音波送受波器と、第1から第2の超音波送受波器への超音波の第1伝播時間と第2から第1の超音波送受波器への超音波の第2伝播時間とを計測する伝播時間計測部とを備えて、第1と第2の超音波送受波器の間の計測管の軸方向における距離をL、第1伝播時間をt1、第2伝播時間をt2とすると、下記式(3)に基づいて流速Vを演算するように構成されると共に、超音波の音速をCとすると、下記式(4)に基づいて超音波の音速Cを演算する音速演算部と、音速Cに基づいて計測管内を流れる気体の種類に応じた標準密度を特定する標準密度特定部とを備えたことを特徴とする請求項2に記載の流量計である。   According to a third aspect of the present invention, the flow velocity detectors are arranged at two different positions in the axial direction of the measurement tube, and the first and second ultrasonic transducers capable of transmitting and receiving ultrasonic waves in both directions, A propagation time measuring unit for measuring the first propagation time of the ultrasonic wave from the first to the second ultrasonic transducer and the second propagation time of the ultrasonic wave from the second to the first ultrasonic transducer. If the distance in the axial direction of the measuring tube between the first and second ultrasonic transducers is L, the first propagation time is t1, and the second propagation time is t2, the following equation (3) is used. It is configured to calculate the flow velocity V, and when the ultrasonic sound velocity is C, the sound velocity calculation unit that calculates the ultrasonic sound velocity C based on the following equation (4), and the inside of the measurement tube based on the sound velocity C are calculated. The flowmeter according to claim 2, further comprising a standard density specifying unit that specifies a standard density according to a type of flowing gas. That.

Figure 2010256075
Figure 2010256075

請求項4の発明は、流速検出部は、計測管の軸方向の異なる2位置に配置され、双方向で超音波を送受波可能な第1と第2の超音波送受波器と、第1から第2の超音波送受波器への超音波の第1伝播時間と第2から第1の超音波送受波器への超音波の第2伝播時間とを計測する伝播時間計測部とを備え、第1と第2の超音波送受波器の間の計測管の軸方向における距離をL、第1伝播時間をt1、第2伝播時間をt2、実際の流速をVとすると、上記式(3)に基づいて流速Vを演算するように構成されると共に、超音波の音速をCとすると、上記式(4)に基づいて超音波の音速Cを演算する音速演算部と、気体の温度とその温度に応じた音速とを対応させた音速・温度データテーブルを備え、温度計測部は、音速演算部にて演算した音速Cに基づいて音速・温度データテーブルから実際の温度を特定することを特徴とする請求項1乃至3の何れか1の請求項に記載の流量計である。   According to a fourth aspect of the present invention, the flow velocity detectors are arranged at two different positions in the axial direction of the measurement tube, and the first and second ultrasonic transducers capable of transmitting and receiving ultrasonic waves in both directions, A propagation time measuring unit for measuring the first propagation time of the ultrasonic wave from the first to the second ultrasonic transducer and the second propagation time of the ultrasonic wave from the second to the first ultrasonic transducer. When the distance in the axial direction of the measuring tube between the first and second ultrasonic transducers is L, the first propagation time is t1, the second propagation time is t2, and the actual flow velocity is V, the above formula ( 3) The flow velocity V is configured to be calculated based on 3), and the sound velocity calculation section for calculating the ultrasonic sound velocity C based on the above equation (4), and the temperature of the gas, where C is the ultrasonic sound velocity. And a sound speed / temperature data table that correlates the sound speed according to the temperature, and the temperature measurement section uses the sound speed calculated by the sound speed calculation section. A flow meter according to any one of claims 1 to 3, characterized in that to determine the actual temperature from the sound velocity and temperature data table based on.

請求項5の発明は、計測管内の気体の流速、静圧、動圧及び温度を検出し、それら検出した実際の静圧と実際の動圧との和である実際の全圧と実際の流速と実際の温度とボイル・シャルルの法則に基づく関係式とを使用して、実際の流速を、予め定めた標準温度及び標準全圧で計測管内の単位面積に流れる気体の標準単位流量に変換するか、又は、標準単位流量に計測管の内側断面積を乗じた標準流量に変換して計測することを特徴とする流量計測方法である。   The invention of claim 5 detects the flow velocity, static pressure, dynamic pressure and temperature of the gas in the measuring tube, and the actual total pressure and the actual flow velocity which are the sum of the detected actual static pressure and the actual dynamic pressure. And the actual temperature and the relational expression based on Boyle-Charles' law, the actual flow velocity is converted into the standard unit flow rate of the gas flowing in the unit area in the measuring tube at the predetermined standard temperature and standard total pressure. Alternatively, the flow rate measurement method is characterized in that it is converted into a standard flow rate obtained by multiplying the standard unit flow rate by the inner cross-sectional area of the measurement tube.

請求項6の発明は、標準温度をT0、標準全圧をP0、標準温度T0及び標準全圧P0下の気体の密度である標準密度をρ0、実際の温度をT1、静圧をP1、動圧をP2、実際の全圧をP3、実際の温度T1及び実際の全圧P3下の気体の密度である計測時密度をρ1、実際の流速をVとすると、上記式(1),(2)に基づいて計測時密度ρ1及び動圧P2を演算することを特徴とする請求項5に記載の流量計測方法である。   In the invention of claim 6, the standard temperature is T0, the standard total pressure is P0, the standard temperature which is the density of the gas under the standard temperature T0 and the standard total pressure P0 is ρ0, the actual temperature is T1, the static pressure is P1, When the pressure is P2, the actual total pressure is P3, the actual temperature T1 and the density at the time of measurement, which is the density of the gas under the actual total pressure P3, is ρ1, and the actual flow velocity is V, the above formulas (1) and (2 6 is a flow rate measurement method according to claim 5, wherein the measurement-time density ρ1 and the dynamic pressure P2 are calculated based on.

請求項7の発明は、計測管の軸方向の異なる2位置に第1と第2の超音波送受波器を配置して、第1から第2の超音波送受波器への超音波の第1伝播時間と第2から第1の超音波送受波器への超音波の第2伝播時間とを計測し、第1と第2の超音波送受波器の間の計測管の軸方向における距離をL、第1伝播時間をt1、第2伝播時間をt2、超音波の音速をCとすると、上記式(3)に基づいて流速Vを演算すると共に、上記式(4)に基づいて超音波の音速Cを演算し、音速Cに基づいて計測管内を流れる気体の種類に応じた標準密度を特定することを特徴とする請求項6に記載の流量計測方法である。   According to the seventh aspect of the present invention, the first and second ultrasonic transducers are arranged at two different positions in the axial direction of the measuring tube, and the ultrasonic waves from the first to the second ultrasonic transducers are transmitted. The first propagation time and the second propagation time of the ultrasonic wave from the second to the first ultrasonic transducer are measured, and the distance in the axial direction of the measuring tube between the first and second ultrasonic transducers Is L, the first propagation time is t1, the second propagation time is t2, and the sound velocity of the ultrasonic wave is C, the flow velocity V is calculated based on the above equation (3), and the superfluidity based on the above equation (4) is calculated. The flow rate measuring method according to claim 6, wherein the sound velocity C of the sound wave is calculated, and the standard density corresponding to the type of gas flowing in the measurement tube is specified based on the sound velocity C.

請求項8の発明は、計測管の軸方向の異なる2位置に第1と第2の超音波送受波器を配置して、第1から第2の超音波送受波器への超音波の第1伝播時間と第2から第1の超音波送受波器への超音波の第2伝播時間とを計測し、第1と第2の超音波送受波器の間の計測管の軸方向における距離をL、第1伝播時間をt1、第2伝播時間をt2、実際の流速をV、超音波の音速をCとすると、上記式(3)に基づいて流速Vを演算すると共に、上記式(4)に基づいて超音波の音速Cを演算し、気体の温度とその温度に応じた音速とを対応させた音速・温度データテーブルを備えておき、音速演算部にて演算した音速Cに基づいて音速・温度データテーブルから実際の温度を特定することを特徴とする請求項5乃至7の何れか1の請求項に記載の流量計測方法である。   In the invention according to claim 8, the first and second ultrasonic transducers are arranged at two different positions in the axial direction of the measuring tube, and the first ultrasonic wave to the second ultrasonic transducer is transmitted. The first propagation time and the second propagation time of the ultrasonic wave from the second to the first ultrasonic transducer are measured, and the distance in the axial direction of the measuring tube between the first and second ultrasonic transducers Is L, the first propagation time is t1, the second propagation time is t2, the actual flow velocity is V, and the ultrasonic sound velocity is C, the flow velocity V is calculated based on the above equation (3), and the above equation ( 4) The sound speed C of the ultrasonic wave is calculated based on 4), and a sound speed / temperature data table in which the gas temperature and the sound speed corresponding to the temperature are associated with each other is provided. Based on the sound speed C calculated by the sound speed calculation unit. The actual temperature is specified from the sound speed / temperature data table. The claim according to any one of claims 5 to 7, Which is a flow rate measurement method.

なお、本発明の願書に添付した明細書及び特許請求の範囲における「温度」は、摂氏と表記するか「℃」を付記しない限り、「絶対温度」を意味するものとする。   “Temperature” in the specification and claims attached to the application of the present invention means “absolute temperature” unless it is expressed as Celsius or “° C.” is added.

[請求項1及び5の発明]
請求項1及び5の発明によれば、流速の大小によって変化する動圧と静圧との和である全圧を使用して標準単位流量又は標準流量を演算しているので、流速の大小にかかわらず、標準単位流量及び標準流量を安定して正確に計測することができる。また、請求項1の発明に係る流量計では、流速を利用して動圧を演算するので、動圧を求めるために動圧計測用のピトー管のような機器を別途設けた構成に比べて、流量計がコンパクトになる。
[Inventions of Claims 1 and 5]
According to the first and fifth aspects of the present invention, the standard unit flow rate or the standard flow rate is calculated using the total pressure that is the sum of the dynamic pressure and the static pressure that change depending on the magnitude of the flow velocity. Regardless, the standard unit flow rate and the standard flow rate can be measured stably and accurately. Further, in the flow meter according to the invention of claim 1, since the dynamic pressure is calculated using the flow velocity, compared to a configuration in which a device such as a Pitot tube for measuring the dynamic pressure is separately provided in order to obtain the dynamic pressure. The flow meter becomes compact.

[請求項2及び6の発明]
請求項2及び6の発明では、動圧の演算において、上記式(1)の通り全圧を使用して気体の計測時密度ρ1を演算するので、計測時密度ρ1の精度も高くなり、その計測時密度ρ1を使用して上記式(2)の通り動圧を演算するので、正確に動圧を演算することができる。
[Inventions of Claims 2 and 6]
In the inventions of claims 2 and 6, in the calculation of the dynamic pressure, the gas measurement density ρ1 is calculated using the total pressure as in the above formula (1), so the accuracy of the measurement density ρ1 is also increased. Since the dynamic pressure is calculated using the measurement density ρ1 as in the above equation (2), the dynamic pressure can be calculated accurately.

[請求項3及び7の発明]
請求項3及び7の発明では、流速を検出するための第1と第2の超音波送受波器を利用して超音波の音速を演算し、その音速の演算結果と、計測管を通過し得る気体の種類に応じた音速と、気体の種類に応じた標準密度とを対応させた音速・密度データテーブルとから標準密度を決定することができるので、計測管に異なる種類の気体が流れ得る場合も、標準単位流量及び標準流量を安定して正確に計測することができる。
[Inventions of Claims 3 and 7]
In the inventions of claims 3 and 7, the first and second ultrasonic transducers for detecting the flow velocity are used to calculate the sound speed of the ultrasonic wave, the calculation result of the sound speed and the measurement tube are passed through. The standard density can be determined from the sound velocity / density data table corresponding to the sound speed according to the type of gas to be obtained and the standard density according to the type of gas, so that different types of gas can flow through the measurement tube. Even in this case, the standard unit flow rate and the standard flow rate can be measured stably and accurately.

[請求項4及び8の発明]
請求項4及び8の発明では、流速を検出するための第1と第2の超音波送受波器を利用して超音波の音速を演算し、その音速の演算結果と、計測管を通過し得る気体の温度とその温度に応じた音速とを対応させた音速・温度データテーブルとから実際の温度を特定するので、温度計を別途設けた構成に比べて、流量計がコンパクトになる。
[Inventions of Claims 4 and 8]
In the inventions of claims 4 and 8, the first and second ultrasonic transducers for detecting the flow velocity are used to calculate the sound speed of the ultrasonic wave, and the calculation result of the sound speed and the measurement pipe are passed through. Since the actual temperature is specified from the sound speed / temperature data table in which the temperature of the gas to be obtained and the sound speed according to the temperature are associated with each other, the flow meter is more compact than a configuration in which a thermometer is separately provided.

本発明の一実施形態に係る超音波流量計のブロック図The block diagram of the ultrasonic flowmeter concerning one embodiment of the present invention. コントローラのブロック図Controller block diagram 音速と温度の関係を説明する図Diagram explaining the relationship between sound speed and temperature

[第1実施形態]
以下、本発明を超音波流量計に適用した実施形態について図1〜図3に基づいて説明する。図1に示すように、本実施形態の超音波流量計10は、計測本体部11とコントローラ20とからなる。計測本体部11は、例えば、ガス管12の途中に取り付けられる円筒状の計測管13を有し、その計測管13の内側面に第1と第2の超音波送受波器14,15を備えている。それら第1と第2の超音波送受波器14,15は、計測管13の中心軸に対して斜めに交差する直線上に配置されている。なお、本実施形態の超音波流量計10が接続されるガス管12には、空気、都市ガス、LPガスの何れかが流れるようになっている。
[First Embodiment]
Hereinafter, an embodiment in which the present invention is applied to an ultrasonic flowmeter will be described with reference to FIGS. As shown in FIG. 1, the ultrasonic flowmeter 10 of this embodiment includes a measurement main body 11 and a controller 20. The measurement main body 11 has, for example, a cylindrical measurement tube 13 attached in the middle of the gas tube 12, and includes first and second ultrasonic transducers 14 and 15 on the inner surface of the measurement tube 13. ing. The first and second ultrasonic transducers 14 and 15 are arranged on a straight line that obliquely intersects the central axis of the measurement tube 13. Note that any one of air, city gas, and LP gas flows through the gas pipe 12 to which the ultrasonic flowmeter 10 of the present embodiment is connected.

計測管13には、その内側の静圧を検出するための静圧計17が一体に設けられている。具体的には、計測管13の軸方向における第1と第2の超音波送受波器14,15の間の中央位置から、軸方向と直交する側方に向けて分岐路16が延ばされ、分岐路16の末端に静圧計17が接続されている。また、静圧計17は、計測管13内の静圧に応じて変形する例えば図示しないダイヤフラムを内蔵し、そのダイヤフラムの変形量を電気信号に変えて出力する。   The measuring tube 13 is integrally provided with a static pressure gauge 17 for detecting the static pressure inside thereof. Specifically, the branch path 16 is extended from the center position between the first and second ultrasonic transducers 14 and 15 in the axial direction of the measuring tube 13 toward the side perpendicular to the axial direction. The hydrostatic pressure gauge 17 is connected to the end of the branch path 16. The static pressure gauge 17 incorporates, for example, a diaphragm (not shown) that deforms in accordance with the static pressure in the measuring tube 13, and changes the deformation amount of the diaphragm into an electrical signal and outputs it.

コントローラ20には、送受波制御回路21と静圧検出回路25と信号処理部30とが備えられている。静圧検出回路25は、静圧計17が出力した電気信号を静圧の検出値に変換して出力する。なお、本実施形態では、静圧計17と静圧検出回路25とから本発明に係る「静圧検出部」が構成されている。   The controller 20 includes a wave transmission / reception control circuit 21, a static pressure detection circuit 25, and a signal processing unit 30. The static pressure detection circuit 25 converts the electrical signal output from the static pressure gauge 17 into a detected value of static pressure and outputs it. In the present embodiment, the “static pressure detector” according to the present invention is constituted by the static pressure gauge 17 and the static pressure detection circuit 25.

送受波制御回路21は、本発明の「伝播時間計測部」に相当し、所定周期でパルスを出力する発振回路(図示せず)と、第1と第2の超音波送受波器14,15に超音波を出力させる送波回路(図示せず)と、第1と第2の超音波送受波器14,15が超音波を受信したことを検出する受波回路(図示せず)とを備えている。そして、第1超音波送受波器14を送波回路に接続する一方、第2超音波送受波器15を受波回路に接続にして、第1超音波送受波器14に超音波を出力させてから、その超音波を第2超音波送受波器15が受信する迄の間に発振回路が出力したパルス数を超音波の第1伝播時間として計測すると共に、第1超音波送受波器14を受波回路に接続する一方、第2超音波送受波器15を送波回路に接続した状態に切り替えて、第2超音波送受波器15に超音波を出力させてから、その超音波を第1超音波送受波器14が受信する迄の間に発振回路が出力したパルス数を超音波の第2伝播時間として計測する。   The transmission / reception control circuit 21 corresponds to the “propagation time measurement unit” of the present invention, and includes an oscillation circuit (not shown) that outputs pulses at a predetermined period, and the first and second ultrasonic transducers 14 and 15. And a wave receiving circuit (not shown) for detecting that the first and second ultrasonic transducers 14 and 15 have received the ultrasonic wave. I have. Then, the first ultrasonic transducer 14 is connected to the transmission circuit, while the second ultrasonic transducer 15 is connected to the reception circuit, and the first ultrasonic transducer 14 outputs the ultrasonic wave. Until the second ultrasonic transducer 15 receives the ultrasonic wave, the number of pulses output by the oscillation circuit is measured as the first propagation time of the ultrasonic wave, and the first ultrasonic transducer 14 is measured. Is switched to a state in which the second ultrasonic transmitter / receiver 15 is connected to the transmitter circuit, and the second ultrasonic transmitter / receiver 15 outputs an ultrasonic wave. The number of pulses output by the oscillation circuit until reception by the first ultrasonic transducer 14 is measured as the second propagation time of the ultrasonic wave.

信号処理部30には、CPU21A、ROM21B、RAM21Cが備えられ、ROM21Bに記憶された図示しないデータ処理プログラムを実行することで、信号処理部30が図2のブロック図に示した制御系として機能する。   The signal processing unit 30 includes a CPU 21A, a ROM 21B, and a RAM 21C. The signal processing unit 30 functions as a control system shown in the block diagram of FIG. 2 by executing a data processing program (not shown) stored in the ROM 21B. .

図2の制御系のうち符号31で示した周波数和演算部は、送受波制御回路21で計測した第1伝播時間の逆数と、第2伝播時間の逆数との和を演算し、符号32で示した周波数差演算部は、第1伝播時間の逆数から第2伝播時間の逆数を減算した値を演算する構成になっている。ここで、第1と第2の超音波送受波器14,15の間の計測管13の軸方向(即ち、気体が流れる方向)における距離をL、第1伝播時間をt1、第2伝播時間をt2、計測管13内を流れる気体の実際の流速をV、超音波の音速をCとし、第1超音波送受波器14が第2超音波送受波器15より上流側に配置されているとすると、下記式(5),(6)の等式が成立する。   2 calculates the sum of the reciprocal of the first propagation time measured by the transmission / reception control circuit 21 and the reciprocal of the second propagation time. The frequency difference calculation unit shown is configured to calculate a value obtained by subtracting the reciprocal of the second propagation time from the reciprocal of the first propagation time. Here, the distance in the axial direction of the measurement tube 13 between the first and second ultrasonic transducers 14 and 15 (that is, the gas flow direction) is L, the first propagation time is t1, and the second propagation time. T2, the actual flow velocity of the gas flowing through the measuring tube 13 is V, the ultrasonic velocity is C, and the first ultrasonic transducer 14 is disposed upstream of the second ultrasonic transducer 15. Then, the following equations (5) and (6) are established.

Figure 2010256075
Figure 2010256075

従って、周波数和演算部31は、第1と第2の伝播時間の逆数の和を演算することで、上記式(5)に示すように音速Cの代用値として(2C/L)を演算している。即ち、周波数和演算部31は、定数(2/L)を乗じた実質的な音速Cxを演算している。また、周波数差演算部32は、第1と第2の伝播時間の逆数の差を演算することで、上記式(6)に示すように、流速Vの代用値として(2V/L)を演算している。即ち、周波数差演算部32は、定数(2/L)を乗じた実質的な流速Vxを演算している。   Therefore, the frequency sum calculation unit 31 calculates (2C / L) as a substitute value of the sound velocity C as shown in the above equation (5) by calculating the sum of the reciprocals of the first and second propagation times. ing. That is, the frequency sum calculation unit 31 calculates a substantial sound speed Cx multiplied by a constant (2 / L). Further, the frequency difference calculation unit 32 calculates (2V / L) as a substitute value of the flow velocity V as shown in the above equation (6) by calculating the difference between the reciprocals of the first and second propagation times. is doing. That is, the frequency difference calculation unit 32 calculates a substantial flow velocity Vx multiplied by a constant (2 / L).

図2の制御系のうち符号33で示した流速演算部は、周波数差演算部32の演算結果にL/2を乗じて代用値ではない真の流速Vを演算する。なお、本実施形態では、これら周波数差演算部32及び流速演算部33と、前述した送受波制御回路21と第1と第2の超音波送受波器14,15とから、本発明に係る「流速検出部」が構成されている。   In the control system of FIG. 2, the flow velocity calculation unit denoted by reference numeral 33 multiplies the calculation result of the frequency difference calculation unit 32 by L / 2 to calculate a true flow velocity V that is not a substitute value. In the present embodiment, the frequency difference calculation unit 32 and the flow velocity calculation unit 33, the above-described transmission / reception control circuit 21, and the first and second ultrasonic transducers 14 and 15 according to the present invention. A “flow velocity detection unit” is configured.

図2の制御系のうち符号34で示したガス種特定部は、周波数和演算部31が演算した実質的な音速Cxに基づいて、計測管13を流れる気体が、空気、都市ガス、LPガスの何れであるかを特定する。ここで、超音波が気体を伝播する際の音速は、その気体の種類によって異なると共に温度によっても異なる。また、本実施形態では、ガス管12を流れる気体の温度が、低くても253.1[K](−20[℃])以上であり、高くても333.1[K](60[℃])以下になっている。さらには、図3には、−20〜60[℃]の温度に対する音速の変化が、空気、都市ガス、LPガス毎に示されている。同図に示すように、253.1〜333.1[K](−20〜60[℃])の範囲では、空気、都市ガス、LPガスの間で音速の値が同一になることはない。そこで、ガス種特定部34は、図3に示した特性に基づいて、第1の下限判定値及び上限判定値と、第2の下限判定値及び上限判定値と、又は、第3の下限判定値及び上限判定値とが設定されていて、実質的な音速Cxが、上記第1〜第3の下限判定値及び上限判定値のうち何れかの下限判定値及び上限判定値の間に収まっているかに基づいて、計測管13を流れる気体が、空気、都市ガス、LPガスの何れであるかを特定するようになっている。   In the control system of FIG. 2, the gas type identification unit indicated by reference numeral 34 is based on the substantial sound velocity Cx calculated by the frequency sum calculation unit 31 and the gas flowing through the measurement tube 13 is air, city gas, LP gas. Is specified. Here, the speed of sound when the ultrasonic wave propagates through the gas varies depending on the type of the gas and also on the temperature. In the present embodiment, the temperature of the gas flowing through the gas pipe 12 is 253.1 [K] (−20 [° C.]) or higher at the lowest, and 333.1 [K] (60 [° C.] at the highest. ]) It is as follows. Furthermore, in FIG. 3, the change of the sound speed with respect to the temperature of -20-60 [degreeC] is shown for every air, city gas, and LP gas. As shown in the figure, in the range of 253.1 to 333.1 [K] (−20 to 60 [° C.]), the value of sonic velocity does not become the same among air, city gas, and LP gas. . Therefore, the gas type identification unit 34, based on the characteristics shown in FIG. 3, the first lower limit determination value and the upper limit determination value, the second lower limit determination value and the upper limit determination value, or the third lower limit determination value. Value and upper limit determination value are set, and the substantial sound speed Cx falls between any of the lower limit determination value and the upper limit determination value among the first to third lower limit determination values and the upper limit determination value. Whether the gas flowing through the measuring tube 13 is air, city gas, or LP gas is specified.

図2の制御系のうち符号35で示した温度特定部は、ガス種特定部34から計測管13を流れる気体のガス種の情報を取得すると共に、周波数和演算部31から実質的な音速Cxの演算値を取得し、それらに基づいて気体の温度を特定する。具体的には、コントローラ20のROM21B(図1参照)には、空気の温度とその温度に応じた実質的な音速Cxとを対応させた第1の音速・温度データテーブル41と、都市ガスの温度とその温度に応じた実質的な音速Cxとを対応させた第2の音速・温度データテーブル42と、LPガスの温度とその温度に応じた実質的な音速Cxとを対応させた第3の音速・温度データテーブル43とが記憶されている。そして、温度特定部35は、ガス種の情報に基づき、計測管13を流れる気体の種類に応じた第1〜第3の何れかの音速・温度データテーブル41,42,43にアクセスし、実質的な音速Cxに基づいて音速・温度データテーブルから気体の温度を特定する。   The temperature specifying unit indicated by reference numeral 35 in the control system of FIG. 2 acquires information on the gas type of the gas flowing through the measuring tube 13 from the gas type specifying unit 34, and the substantial sound speed Cx from the frequency sum calculating unit 31. Are obtained, and the temperature of the gas is specified based on them. Specifically, the ROM 21B (see FIG. 1) of the controller 20 includes a first sound speed / temperature data table 41 that associates the temperature of air with a substantial sound speed Cx corresponding to the temperature, and the city gas. The second sonic velocity / temperature data table 42 in which the temperature and the substantial sonic velocity Cx corresponding to the temperature are associated with each other, and the LP gas temperature and the substantial sonic velocity Cx corresponding to the temperature are associated with each other. The sound speed / temperature data table 43 is stored. And the temperature specific | specification part 35 accesses one of the 1st-3rd sound speed and temperature data tables 41, 42, and 43 according to the kind of gas which flows through the measurement pipe | tube 13 based on the information of gas type, and is substantially The gas temperature is specified from the sound speed / temperature data table based on the typical sound speed Cx.

図2の制御系のうち符号36で示した標準密度特定部は、温度特定部35から気体のガス種の情報を取得し、その気体のガス種の情報に基づいて、予め設定された標準温度及び標準全圧下における気体の密度としての標準密度を特定する。ここで、本実施形態の超音波流量計10では、標準温度として273.1[K](摂氏0[℃])、標準全圧として101.3[kPa](1気圧)が予め設定され、それら標準温度273.1[K]、標準全圧101.3[kPa]のデータが前記した図示しないデータ処理プログラム中に組み込まれてROM21B(図1参照)に記憶されている。また、ROM21Bには、ガス種の情報と空気、都市ガス、LPガスの標準密度とを対応させた密度データベース44が記憶されている。そして、標準密度特定部36は、気体のガス種の情報に基づいてROM21Bの密度データベース44から計測管13内を流れる気体の標準密度を取得する。   The standard density specifying unit denoted by reference numeral 36 in the control system of FIG. 2 acquires information on the gas type of the gas from the temperature specifying unit 35, and sets a standard temperature set in advance based on the information on the gas type of the gas. And the standard density as the density of the gas under standard total pressure. Here, in the ultrasonic flowmeter 10 of the present embodiment, 273.1 [K] (0 degrees Celsius) as the standard temperature and 101.3 [kPa] (1 atmosphere) as the standard total pressure are preset, The data of the standard temperature 273.1 [K] and the standard total pressure 101.3 [kPa] are incorporated in the data processing program (not shown) and stored in the ROM 21B (see FIG. 1). The ROM 21B stores a density database 44 in which information on gas types is associated with standard densities of air, city gas, and LP gas. And the standard density specific | specification part 36 acquires the standard density of the gas which flows through the inside of the measurement pipe | tube 13 from the density database 44 of ROM21B based on the information of gaseous gas type.

また、標準密度特定部36は、流速演算部33から気体の流速の演算結果を取得すると共に、静圧検出回路25から静圧の検出結果を取得し、下記式(1),(2)を利用して、計測管13内の実際の温度及び実際の全圧下の気体の密度である計測時密度を演算する。即ち、標準温度をT0、標準全圧をP0、標準密度をρ0、実際の温度をT1、静圧をP1、動圧をP2、計測時密度をρ1、実際の流速をVとすると、以下の式(1),(2)が成立する。   Further, the standard density specifying unit 36 acquires the calculation result of the gas flow velocity from the flow velocity calculation unit 33 and also acquires the detection result of the static pressure from the static pressure detection circuit 25, and the following equations (1) and (2) are obtained. Utilizing this, the density at the time of measurement, which is the actual temperature in the measuring tube 13 and the actual gas density under the total pressure, is calculated. That is, assuming that the standard temperature is T0, the standard total pressure is P0, the standard density is ρ0, the actual temperature is T1, the static pressure is P1, the dynamic pressure is P2, the measurement density is ρ1, and the actual flow velocity is V, Expressions (1) and (2) are established.

Figure 2010256075
Figure 2010256075

具体的には、標準密度特定部36は、まず、式(1)においてP2=0として計測時密度ρ1を演算する。次に、計測時密度ρ1と式(2)から動圧P2を演算し、得られた動圧P2と式(1)から再び計測時密度ρ1を演算する。このように式(1),(2)を繰り返し用いて、計測時密度ρ1を演算する。   Specifically, the standard density specifying unit 36 first calculates the measurement density ρ1 with P2 = 0 in the equation (1). Next, the dynamic pressure P2 is calculated from the measured density ρ1 and the equation (2), and the measured density ρ1 is calculated again from the obtained dynamic pressure P2 and the equation (1). In this way, the measurement density ρ1 is calculated by repeatedly using the equations (1) and (2).

なお、式(1),(2)を変形すると下記式(7)になる。標準密度特定部36はこの式(7)から計測時密度ρ1を演算してもよい。   Note that the following formula (7) is obtained by modifying the formulas (1) and (2). The standard density specifying unit 36 may calculate the measurement density ρ1 from the equation (7).

Figure 2010256075
Figure 2010256075

また、標準密度特定部36は、式(1)においてP2=0として、即ち、式(1),(2)の繰り返し用いないで計測時密度ρ1を簡易的に演算してもよい。   Further, the standard density specifying unit 36 may simply calculate the measurement density ρ1 by setting P2 = 0 in the equation (1), that is, without repeatedly using the equations (1) and (2).

図2の制御系のうち符号37で示した動圧演算部は、標準密度特定部36から計測時密度ρ1を取得すると共に、流速演算部33から流速Vを取得して、上記式(2)から気体の動圧P2を演算する。   The dynamic pressure calculation unit indicated by reference numeral 37 in the control system of FIG. 2 acquires the measured density ρ1 from the standard density specifying unit 36 and the flow velocity V from the flow velocity calculation unit 33, and the above equation (2). From this, the gas dynamic pressure P2 is calculated.

図2の制御系のうち符号38で示した全圧演算部は、動圧演算部37から動圧P2を取得すると共に、静圧検出回路25から静圧P1を取得して、静圧P1及び動圧P2の和で全圧P3(=P1+P2)を演算する。   The total pressure calculation unit denoted by reference numeral 38 in the control system of FIG. 2 acquires the dynamic pressure P2 from the dynamic pressure calculation unit 37, acquires the static pressure P1 from the static pressure detection circuit 25, and generates the static pressure P1 and The total pressure P3 (= P1 + P2) is calculated by the sum of the dynamic pressure P2.

図2の制御系のうち符号39で示した標準単位流量演算部は、全圧演算部38から全圧P3を取得し、流速演算部33から流速Vを取得し、温度特定部35から温度T1の情報を取得して、ボイル・シャルルの法則に基づいた下記式(8)から標準単位流量Qxを演算する。ここで、標準単位流量Qxは、任意の温度及び圧力で流れる気体の実際の流速を、前記した標準温度及び標準全圧で、計測管13内の単位面積に流れる気体の流量である。つまり、標準単位流量Qxは、標準温度及び標準全圧下で計測管13内を流れる気体の流速でもある。   The standard unit flow rate calculation unit indicated by reference numeral 39 in the control system of FIG. 2 acquires the total pressure P3 from the total pressure calculation unit 38, acquires the flow rate V from the flow rate calculation unit 33, and the temperature T1 from the temperature specifying unit 35. The standard unit flow rate Qx is calculated from the following equation (8) based on Boyle-Charles' law. Here, the standard unit flow rate Qx is the flow rate of the gas flowing in the unit area in the measuring tube 13 at the above-described standard temperature and standard total pressure at the actual flow velocity of the gas flowing at an arbitrary temperature and pressure. That is, the standard unit flow rate Qx is also the flow velocity of the gas flowing in the measurement tube 13 under the standard temperature and the standard total pressure.

Figure 2010256075
Figure 2010256075

図2の制御系のうち符号40で示した標準流量演算部は、標準単位流量演算部39から標準単位流量Qxを取得し、その標準単位流量Qxに計測管13の内側断面積を乗じて、標準流量Qを演算する。そして、これら標準単位流量Qx及び標準流量Qが信号処理部30から図1に示したコントローラ20の出力回路22に付与され、その出力回路22から超音波流量計10外に出力される。   2 obtains the standard unit flow rate Qx from the standard unit flow rate computation unit 39, multiplies the standard unit flow rate Qx by the inner cross-sectional area of the measuring tube 13, The standard flow rate Q is calculated. Then, the standard unit flow rate Qx and the standard flow rate Q are given from the signal processing unit 30 to the output circuit 22 of the controller 20 shown in FIG. 1 and output from the output circuit 22 to the outside of the ultrasonic flow meter 10.

上記したように本実施形態の超音波流量計10では、気体の流速Vの大小によって変化する動圧P2と静圧P1との和である全圧を使用して標準単位流量Qx及び標準流量Qを演算しているので、流速Vの大小にかかわらず、標準単位流量Qx及び標準流量Qを安定して正確に計測することができる。しかも、第1と第2の超音波送受波器14,15が計測管13全体を横切るように超音波を送受波して流速Vを検出しているので、計測管13全体の平均した流速Vが検出され、この点においても、標準単位流量Qx及び標準流量Qを正確に計測することができる。さらには、全圧P3を使用して気体の計測時密度ρ1を演算するので計測時密度ρ1の精度も高くなり、その計測時密度ρ1を使用して動圧P2を演算するので、この点においても高い精度で動圧P2を演算することができる。   As described above, in the ultrasonic flow meter 10 of the present embodiment, the standard unit flow rate Qx and the standard flow rate Q are obtained using the total pressure that is the sum of the dynamic pressure P2 and the static pressure P1 that change depending on the magnitude of the gas flow velocity V. Therefore, regardless of the flow velocity V, the standard unit flow rate Qx and the standard flow rate Q can be stably and accurately measured. Moreover, since the first and second ultrasonic transducers 14 and 15 transmit and receive ultrasonic waves across the entire measurement tube 13 and detect the flow velocity V, the average flow velocity V of the entire measurement tube 13 is detected. In this respect, the standard unit flow rate Qx and the standard flow rate Q can be accurately measured. Furthermore, since the measurement density ρ1 of the gas is calculated using the total pressure P3, the accuracy of the measurement density ρ1 is also increased, and the dynamic pressure P2 is calculated using the measurement density ρ1. The dynamic pressure P2 can be calculated with high accuracy.

また、流速Vを検出するための第1と第2の超音波送受波器14,15を利用して超音波の音速Cを演算し、その音速Cから計測管13内を流れる気体の種類を特定するので、計測管13に異なる種類の気体が流れ得る場合も、標準単位流量Qx及び標準流量Qを安定して正確に計測することができる。また、流速Vを利用して動圧P2を演算するので、動圧P2を求めるために例えば動圧計測用のピトー管のような機器を別途設けた構成に比べて、超音波流量計10がコンパクトになる。さらには、音速Cの演算結果から実際の温度T1を特定するので、温度計を別途設けた構成に比べて超音波流量計10がコンパクトになる。   Further, the first and second ultrasonic transducers 14 and 15 for detecting the flow velocity V are used to calculate the ultrasonic sound velocity C, and the type of gas flowing in the measuring tube 13 from the sound velocity C is calculated. Therefore, even when different types of gases can flow through the measurement tube 13, the standard unit flow rate Qx and the standard flow rate Q can be stably and accurately measured. In addition, since the dynamic pressure P2 is calculated using the flow velocity V, the ultrasonic flowmeter 10 is compared with a configuration in which a device such as a Pitot tube for measuring the dynamic pressure is separately provided in order to obtain the dynamic pressure P2. It becomes compact. Furthermore, since the actual temperature T1 is specified from the calculation result of the sound velocity C, the ultrasonic flowmeter 10 is more compact than a configuration in which a thermometer is separately provided.

[他の実施形態]
本発明は、前記実施形態に限定されるものではなく、例えば、以下に説明するような実施形態も本発明の技術的範囲に含まれ、さらに、下記以外にも要旨を逸脱しない範囲内で種々変更して実施することができる。
[Other Embodiments]
The present invention is not limited to the above-described embodiment. For example, the embodiments described below are also included in the technical scope of the present invention, and various other than the following can be made without departing from the scope of the invention. It can be changed and implemented.

(1)前記実施形態では、音速Cの演算結果から実際の温度T1を特定していたが、実際の温度T1を温度計により計測してもよい。このような構成であっても、流速Vの大小にかかわらず、標準単位流量Qx及び標準流量Qを安定して計測することができる。   (1) In the above embodiment, the actual temperature T1 is specified from the calculation result of the sound velocity C. However, the actual temperature T1 may be measured by a thermometer. Even with such a configuration, the standard unit flow rate Qx and the standard flow rate Q can be stably measured regardless of the magnitude of the flow velocity V.

(2)前記実施形態において、実質的な音速Cxが第1〜3の下限判定値及び上限判定値の何れの下限判定値及び上限判定値の間にも属さない場合にアラームなどの警報を発する警報装置を備えた構成としてもよい。これにより、空気、都市ガス、LPガス以外のガス混入検知を図ることができる。   (2) In the above-described embodiment, an alarm or the like is issued when the substantial sound speed Cx does not belong to any of the lower limit determination value and the upper limit determination value of the first to third lower limit determination values and the upper limit determination value. It is good also as a structure provided with the alarm device. Thereby, gas mixture detection other than air, city gas, and LP gas can be aimed at.

10 超音波流量計
14 第1超音波送受波器
15 第2超音波送受波器
17 静圧計
21 送受波制御回路
25 静圧検出回路
33 流速演算部
34 ガス種特定部
35 温度特定部
36 標準密度特定部
37 動圧演算部
38 全圧演算部
39 標準単位流量演算部
40 標準流量演算部
DESCRIPTION OF SYMBOLS 10 Ultrasonic flowmeter 14 1st ultrasonic transducer 15 2nd ultrasonic transducer 17 Static pressure meter 21 Transmission / reception control circuit 25 Static pressure detection circuit 33 Flow velocity calculating part 34 Gas type specific | specification part 35 Temperature specific part 36 Standard density Specific unit 37 Dynamic pressure calculation unit 38 Total pressure calculation unit 39 Standard unit flow rate calculation unit 40 Standard flow rate calculation unit

Claims (8)

計測管内の気体の流速を検出可能な流速検出部と、
前記計測管内の気体の静圧を検出可能な静圧検出部と、
前記流速から前記気体の動圧を演算する動圧演算部と、
前記静圧及び前記動圧の和で全圧を演算する全圧演算部と、
前記計測管内の気体の温度を検出可能な温度検出部と、
前記流速検出部、前記温度検出部及び前記全圧演算部にて検出した実際の流速、実際の温度及び実際の全圧と、ボイル・シャルルの法則に基づく関係式とを使用して、前記実際の流速を、予め定めた標準温度及び標準全圧で前記計測管内の単位面積に流れる気体の標準単位流量に変換するか、又は、前記標準単位流量に前記計測管の内側断面積を乗じた標準流量に変換する標準変換部とを備えたことを特徴とする流量計。
A flow rate detector that can detect the flow rate of the gas in the measurement tube;
A static pressure detector capable of detecting the static pressure of the gas in the measuring tube;
A dynamic pressure calculator that calculates the dynamic pressure of the gas from the flow velocity;
A total pressure calculation unit that calculates a total pressure by the sum of the static pressure and the dynamic pressure;
A temperature detector capable of detecting the temperature of the gas in the measuring tube;
Using the actual flow velocity detected by the flow velocity detection unit, the temperature detection unit, and the total pressure calculation unit, the actual temperature and the actual total pressure, and the relational expression based on Boyle-Charles' law, Is converted to a standard unit flow rate of gas flowing in a unit area in the measurement tube at a predetermined standard temperature and standard total pressure, or a standard obtained by multiplying the standard unit flow rate by an inner cross-sectional area of the measurement tube. A flow meter comprising a standard conversion unit for converting into a flow rate.
前記標準温度をT0、前記標準全圧をP0、前記標準温度T0及び前記標準全圧P0下の気体の密度である標準密度をρ0、前記実際の温度をT1、前記静圧をP1、前記動圧をP2、前記実際の温度T1及び前記実際の全圧下の気体の密度である計測時密度をρ1、前記実際の流速をVとすると、
前記動圧演算部は、
Figure 2010256075
、の式に基づいて前記計測時密度ρ1及び前記動圧P2を演算することを特徴とする請求項1に記載の流量計。
The standard temperature is T0, the standard total pressure is P0, the standard density that is the density of the gas under the standard temperature T0 and the standard total pressure P0 is ρ0, the actual temperature is T1, the static pressure is P1, the dynamic When the pressure is P2, the actual temperature T1 and the density at the measurement, which is the density of the gas under the actual total pressure, is ρ1, and the actual flow velocity is V,
The dynamic pressure calculator is
Figure 2010256075
The flowmeter according to claim 1, wherein the measurement density ρ <b> 1 and the dynamic pressure P <b> 2 are calculated based on the following formula.
前記流速検出部は、前記計測管の軸方向の異なる2位置に配置され、双方向で超音波を送受波可能な第1と第2の超音波送受波器と、前記第1から第2の超音波送受波器への超音波の第1伝播時間と前記第2から第1の超音波送受波器への超音波の第2伝播時間とを計測する伝播時間計測部とを備えて、
前記第1と第2の超音波送受波器の間の前記計測管の軸方向における距離をL、前記第1伝播時間をt1、前記第2伝播時間をt2とすると、
Figure 2010256075
、の式に基づいて前記流速Vを演算するように構成されると共に、前記超音波の音速をCとすると、
Figure 2010256075
、の式に基づいて前記超音波の音速Cを演算する音速演算部と、前記音速Cに基づいて前記計測管内を流れる気体の種類に応じた前記標準密度を特定する標準密度特定部とを備えたことを特徴とする請求項2に記載の流量計。
The flow velocity detectors are arranged at two different positions in the axial direction of the measuring tube, and are capable of transmitting and receiving ultrasonic waves in both directions, and the first to second ultrasonic transducers. A propagation time measuring unit for measuring the first propagation time of the ultrasonic wave to the ultrasonic transducer and the second propagation time of the ultrasonic wave from the second to the first ultrasonic transducer;
When the distance in the axial direction of the measurement tube between the first and second ultrasonic transducers is L, the first propagation time is t1, and the second propagation time is t2,
Figure 2010256075
The flow velocity V is calculated on the basis of the equation (2), and the sound velocity of the ultrasonic wave is C.
Figure 2010256075
A sound speed calculation unit that calculates the sound speed C of the ultrasonic wave based on the equation (1), and a standard density specifying unit that specifies the standard density corresponding to the type of gas flowing in the measurement tube based on the sound speed C. The flow meter according to claim 2, wherein
前記流速検出部は、前記計測管の軸方向の異なる2位置に配置され、双方向で超音波を送受波可能な第1と第2の超音波送受波器と、前記第1から第2の超音波送受波器への超音波の第1伝播時間と前記第2から第1の超音波送受波器への超音波の第2伝播時間とを計測する伝播時間計測部とを備え、
前記第1と第2の超音波送受波器の間の前記計測管の軸方向における距離をL、前記第1伝播時間をt1、前記第2伝播時間をt2、前記実際の流速をVとすると、

Figure 2010256075
、の式に基づいて前記流速Vを演算するように構成されると共に、前記超音波の音速をCとすると、
Figure 2010256075
、の式に基づいて前記超音波の音速Cを演算する音速演算部と、前記気体の温度とその温度に応じた音速とを対応させた音速・温度データテーブルを備え、
前記温度計測部は、前記音速演算部にて演算した音速Cに基づいて前記音速・温度データテーブルから前記実際の温度を特定することを特徴とする請求項1乃至3の何れか1の請求項に記載の流量計。
The flow velocity detectors are arranged at two different positions in the axial direction of the measuring tube, and are capable of transmitting and receiving ultrasonic waves in both directions, and the first to second ultrasonic transducers. A propagation time measuring unit for measuring the first propagation time of the ultrasonic wave to the ultrasonic transducer and the second propagation time of the ultrasonic wave from the second to the first ultrasonic transducer;
When the distance in the axial direction of the measuring tube between the first and second ultrasonic transducers is L, the first propagation time is t1, the second propagation time is t2, and the actual flow velocity is V. ,

Figure 2010256075
The flow velocity V is calculated on the basis of the equation (2), and the sound velocity of the ultrasonic wave is C.
Figure 2010256075
A sound speed calculation unit for calculating the sound speed C of the ultrasonic wave based on the equation, and a sound speed / temperature data table in which the temperature of the gas and the sound speed corresponding to the temperature are associated with each other.
The temperature measurement unit identifies the actual temperature from the sound speed / temperature data table based on the sound speed C calculated by the sound speed calculation unit. The flow meter described in 1.
計測管内の気体の流速、静圧、動圧及び温度を検出し、それら検出した実際の静圧と実際の動圧との和である実際の全圧と実際の流速と実際の温度とボイル・シャルルの法則に基づく関係式とを使用して、前記実際の流速を、予め定めた標準温度及び標準全圧で前記計測管内の単位面積に流れる気体の標準単位流量に変換するか、又は、前記標準単位流量に前記計測管の内側断面積を乗じた標準流量に変換して計測することを特徴とする流量計測方法。   The flow velocity, static pressure, dynamic pressure, and temperature of the gas in the measuring tube are detected, and the actual total pressure, the actual flow velocity, the actual temperature, and the boil, the sum of the detected actual static pressure and the actual dynamic pressure are detected. Using the relational expression based on Charles' law, the actual flow velocity is converted into a standard unit flow rate of a gas flowing in a unit area in the measuring tube at a predetermined standard temperature and standard total pressure, or A flow rate measuring method, wherein the flow rate is converted into a standard flow rate obtained by multiplying the standard unit flow rate by the inner cross-sectional area of the measuring tube. 前記標準温度をT0、前記標準全圧をP0、前記標準温度T0及び前記標準全圧P0下の気体の密度である標準密度をρ0、前記実際の温度をT1、前記静圧をP1、前記動圧をP2、前記実際の温度T1及び前記実際の全圧下の気体の密度である計測時密度をρ1、前記実際の流速をVとすると、
Figure 2010256075
、の式に基づいて前記計測時密度ρ1及び前記動圧P2を演算することを特徴とする請求項5に記載の流量計測方法。
The standard temperature is T0, the standard total pressure is P0, the standard density that is the density of the gas under the standard temperature T0 and the standard total pressure P0 is ρ0, the actual temperature is T1, the static pressure is P1, the dynamic When the pressure is P2, the actual temperature T1 and the density at the measurement, which is the density of the gas under the actual total pressure, is ρ1, and the actual flow velocity is V,
Figure 2010256075
The flow rate measuring method according to claim 5, wherein the measurement density ρ1 and the dynamic pressure P2 are calculated based on the following formula.
前記計測管の軸方向の異なる2位置に第1と第2の超音波送受波器を配置して、前記第1から第2の超音波送受波器への超音波の第1伝播時間と前記第2から第1の超音波送受波器への超音波の第2伝播時間とを計測し、
前記第1と第2の超音波送受波器の間の前記計測管の軸方向における距離をL、前記第1伝播時間をt1、前記第2伝播時間をt2、前記超音波の音速をCとすると、
Figure 2010256075
、の式に基づいて前記流速Vを演算すると共に、
Figure 2010256075
、の式に基づいて前記超音波の音速Cを演算し、前記音速に基づいて前記計測管内を流れる気体の種類に応じた前記標準密度を特定することを特徴とする請求項6に記載の流量計測方法。
The first and second ultrasonic transducers are arranged at two different positions in the axial direction of the measurement tube, and the first propagation time of the ultrasonic waves from the first to the second ultrasonic transducers and the Measuring the second propagation time of the ultrasonic wave from the second to the first ultrasonic transducer;
The distance between the first and second ultrasonic transducers in the axial direction of the measuring tube is L, the first propagation time is t1, the second propagation time is t2, and the ultrasonic sound velocity is C. Then
Figure 2010256075
And calculating the flow velocity V based on the formula
Figure 2010256075
The flow rate according to claim 6, wherein a sound velocity C of the ultrasonic wave is calculated based on the formula, and the standard density corresponding to the type of gas flowing in the measuring tube is identified based on the sound velocity. Measurement method.
前記計測管の軸方向の異なる2位置に第1と第2の超音波送受波器を配置して、前記第1から第2の超音波送受波器への超音波の第1伝播時間と前記第2から第1の超音波送受波器への超音波の第2伝播時間とを計測し、
前記第1と第2の超音波送受波器の間の前記計測管の軸方向における距離をL、前記第1伝播時間をt1、前記第2伝播時間をt2、前記実際の流速をV、前記超音波の音速をCとすると、
Figure 2010256075
、の式に基づいて前記流速Vを演算すると共に、
Figure 2010256075
、の式に基づいて前記超音波の音速Cを演算し、前記気体の温度とその温度に応じた音速とを対応させた音速・温度データテーブルを備えておき、
前記音速演算部の演算結果に基づいて前記音速・温度データテーブルから前記実際の温度を特定することを特徴とする請求項5乃至7の何れか1の請求項に記載の流量計測方法。
The first and second ultrasonic transducers are arranged at two different positions in the axial direction of the measurement tube, and the first propagation time of the ultrasonic waves from the first to the second ultrasonic transducers and the Measuring the second propagation time of the ultrasonic wave from the second to the first ultrasonic transducer;
The distance in the axial direction of the measurement tube between the first and second ultrasonic transducers is L, the first propagation time is t1, the second propagation time is t2, the actual flow velocity is V, If the ultrasonic velocity is C,
Figure 2010256075
And calculating the flow velocity V based on the formula
Figure 2010256075
The sound speed C of the ultrasonic wave is calculated on the basis of the equation, and a sound speed / temperature data table in which the temperature of the gas is associated with the sound speed corresponding to the temperature is prepared.
The flow rate measuring method according to claim 5, wherein the actual temperature is specified from the sound speed / temperature data table based on a calculation result of the sound speed calculation unit.
JP2009103998A 2009-04-22 2009-04-22 Flowmeter and method of measuring flow rate Pending JP2010256075A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2009103998A JP2010256075A (en) 2009-04-22 2009-04-22 Flowmeter and method of measuring flow rate

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2009103998A JP2010256075A (en) 2009-04-22 2009-04-22 Flowmeter and method of measuring flow rate

Publications (1)

Publication Number Publication Date
JP2010256075A true JP2010256075A (en) 2010-11-11

Family

ID=43317175

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2009103998A Pending JP2010256075A (en) 2009-04-22 2009-04-22 Flowmeter and method of measuring flow rate

Country Status (1)

Country Link
JP (1) JP2010256075A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013099724A1 (en) * 2011-12-27 2013-07-04 三菱重工業株式会社 Mist-containing gas analysis device
JP2014071058A (en) * 2012-10-01 2014-04-21 Aichi Tokei Denki Co Ltd Ultrasonic flowmeter
JP2017096979A (en) * 2017-01-30 2017-06-01 愛知時計電機株式会社 Ultrasonic flowmeter
JP2017111140A (en) * 2015-12-15 2017-06-22 株式会社堀場製作所 Flow rate measurement device, fuel consumption measurement device, program for flow rate measurement device, and flow rate measuring method

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6379013A (en) * 1986-09-22 1988-04-09 Toyota Central Res & Dev Lab Inc Flow measuring apparatus
JPS63131027A (en) * 1986-11-19 1988-06-03 Tokyo Keiki Co Ltd Ultrasonic gas flowmeter
JPH09329477A (en) * 1996-06-10 1997-12-22 Nikkei Kk Dynamic pressure measurement
JPH10206202A (en) * 1997-01-24 1998-08-07 Nagano Keiki Co Ltd Composite sensor
JP2000221068A (en) * 1999-01-29 2000-08-11 Kansai Gas Meter Co Ltd Ultrasonic flow speed measuring method
JP2000337938A (en) * 1999-06-01 2000-12-08 Aichi Tokei Denki Co Ltd Gas meter
JP2001082994A (en) * 1999-09-14 2001-03-30 Yazaki Corp Flow measuring apparatus
JP2005003678A (en) * 2003-05-20 2005-01-06 Nippon Applied Flow Kk Flow measuring instrument, flow rate measuring instrument, and flow rate instrumentation method
JP2007017157A (en) * 2005-07-05 2007-01-25 Aichi Tokei Denki Co Ltd Ultrasonic flowmeter

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6379013A (en) * 1986-09-22 1988-04-09 Toyota Central Res & Dev Lab Inc Flow measuring apparatus
JPS63131027A (en) * 1986-11-19 1988-06-03 Tokyo Keiki Co Ltd Ultrasonic gas flowmeter
JPH09329477A (en) * 1996-06-10 1997-12-22 Nikkei Kk Dynamic pressure measurement
JPH10206202A (en) * 1997-01-24 1998-08-07 Nagano Keiki Co Ltd Composite sensor
JP2000221068A (en) * 1999-01-29 2000-08-11 Kansai Gas Meter Co Ltd Ultrasonic flow speed measuring method
JP2000337938A (en) * 1999-06-01 2000-12-08 Aichi Tokei Denki Co Ltd Gas meter
JP2001082994A (en) * 1999-09-14 2001-03-30 Yazaki Corp Flow measuring apparatus
JP2005003678A (en) * 2003-05-20 2005-01-06 Nippon Applied Flow Kk Flow measuring instrument, flow rate measuring instrument, and flow rate instrumentation method
JP2007017157A (en) * 2005-07-05 2007-01-25 Aichi Tokei Denki Co Ltd Ultrasonic flowmeter

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013099724A1 (en) * 2011-12-27 2013-07-04 三菱重工業株式会社 Mist-containing gas analysis device
JP2013134153A (en) * 2011-12-27 2013-07-08 Mitsubishi Heavy Ind Ltd Mist-containing gas analysis apparatus
US9395342B2 (en) 2011-12-27 2016-07-19 Mitsubishi Heavy Industries, Ltd. Mist-containing gas analysis device
JP2014071058A (en) * 2012-10-01 2014-04-21 Aichi Tokei Denki Co Ltd Ultrasonic flowmeter
JP2017111140A (en) * 2015-12-15 2017-06-22 株式会社堀場製作所 Flow rate measurement device, fuel consumption measurement device, program for flow rate measurement device, and flow rate measuring method
JP2017096979A (en) * 2017-01-30 2017-06-01 愛知時計電機株式会社 Ultrasonic flowmeter

Similar Documents

Publication Publication Date Title
KR20160029656A (en) Ultrasonic flowmeter and method for measuring flow rate
JP4535065B2 (en) Doppler ultrasonic flow meter
JP2020109360A (en) Ultrasonic gas flowmeter
CN104729582A (en) Temperature detection method for ultrasonic flow detection and ultrasonic flow metering device
JP2010256075A (en) Flowmeter and method of measuring flow rate
CN108351239A (en) Flow measurement device based on vortex flow measuring principle
JP2007051913A (en) Correction method for ultrasonic flowmeter
JP2007187506A (en) Ultrasonic flowmeter
JP2006078362A (en) Coaxial-type doppler ultrasonic current meter
JP5282955B2 (en) Ultrasonic flow meter correction method and ultrasonic flow meter
RU2396518C2 (en) Method and device for acoustic measurement of gas flow rate
JP5934622B2 (en) Temperature measuring instrument, flow meter and temperature measuring method
EP3063508A1 (en) A flow meter for ultrasonically measuring the flow velocity of fluids
JP2010223855A (en) Ultrasonic flowmeter
Chun et al. Assessment of combined V/Z clamp-on ultrasonic flow metering
KR101522249B1 (en) a gas mass flow meter program using ultra sonic wave and the measuring device using thereof
JP5663288B2 (en) Ultrasonic measuring device
JP7151344B2 (en) Pressure measuring device
WO2019097570A1 (en) Ultrasonic flow-rate measurement device and ultrasonic flow-amount measurement method
JP6876643B2 (en) Ultrasonic flow measuring device and ultrasonic flow measuring method
JP2016206147A (en) Ultrasonic type thermal energy meter
JP2020159790A (en) Measurement position determination method and ultrasonic flowmeter
JP7037883B2 (en) Exhaust flow rate measuring device, fuel consumption measuring device, program for exhaust gas flow rate measuring device, and exhaust gas flow rate measuring method
JP4561071B2 (en) Flow measuring device
JPH0882540A (en) Ultrasonic flow-rate measuring method and ultrasonic flowmeter

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20120229

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20130612

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20130717

A02 Decision of refusal

Free format text: JAPANESE INTERMEDIATE CODE: A02

Effective date: 20131113