JP5634113B2

JP5634113B2 - Ultrasonic flow meter

Info

Publication number: JP5634113B2
Application number: JP2010105473A
Authority: JP
Inventors: 英二三村; 一成浅利; 谷口　和彦; 和彦谷口; 正人江川
Original assignee: Kansai Electric Power Co Inc
Current assignee: Kansai Electric Power Co Inc
Priority date: 2010-04-30
Filing date: 2010-04-30
Publication date: 2014-12-03
Anticipated expiration: 2030-04-30
Also published as: JP2011232297A

Description

本発明は、超音波を用いて気体又は液体の流速を求める超音波流量計に関する。 The present invention relates to an ultrasonic flowmeter that determines the flow velocity of a gas or liquid using ultrasonic waves.

従来、都市ガス、水などの流体の流量を計測する流量計測装置として、超音波を利用して流速を測定する超音波流量計が知られている。その際の測定原理として、一般には、「伝搬時間差法」が用いられる。これは、流路の流体の流れ方向上手側および下手側に一対の超音波送受信部（振動子）を設け、超音波信号の送受信を交互に切り替えて、流れ方向上手側の超音波送信部（送信側の振動子）から流れ方向下手側の超音波受信部（受信側の振動子）に到達するまでの時間（以下、順方向応答時間という）と、流れ方向下手側の超音波送信部（送信側の振動子）から流れ方向上手側の超音波受信部（受信側超音波素子）に到達するまでの時間（以下、逆方向応答時間という）とを計測して、両者の時間差から流路を流れる流体の平均流速および流量を求める方法である。 2. Description of the Related Art Conventionally, an ultrasonic flowmeter that measures flow velocity using ultrasonic waves is known as a flow measurement device that measures the flow rate of a fluid such as city gas or water. In general, a “propagation time difference method” is used as a measurement principle at that time. This is provided with a pair of ultrasonic transmission / reception units (vibrators) on the upper and lower sides of the flow direction of the fluid in the flow path, and alternately switching transmission / reception of ultrasonic signals, The time from the transmission side transducer) to the ultrasonic receiving unit on the lower side in the flow direction (reception side transducer) (hereinafter referred to as forward response time), and the ultrasonic transmission unit on the lower side in the flow direction ( The time required to reach the ultrasonic receiving unit (receiving ultrasonic element) on the upper side in the flow direction from the transmitting transducer) (hereinafter referred to as reverse response time) is measured, and the flow path is determined from the time difference between the two. The average flow velocity and flow rate of the fluid flowing through

ここで、「伝搬時間差法」の中でも、超音波送受信部の配設位置によって、一般に「Ｖ透過法」と呼ばれる測定方法と、一般に「斜め透過法」と呼ばれる測定方法の２つがある。以下、これら「Ｖ透過法」及び「斜め透過法」のそれぞれについて説明する。 Here, among the “propagation time difference methods”, there are two measurement methods, generally referred to as “V transmission method” and measurement methods generally referred to as “oblique transmission method”, depending on the arrangement position of the ultrasonic transmission / reception unit. Hereinafter, each of these “V transmission method” and “oblique transmission method” will be described.

「Ｖ透過法」においては、例えば、図９（ａ）に示したように、配管３００の外表面に配設されている超音波プローブ３０１が用いられる。この超音波プローブ３０１は、プローブケース３０２と、プローブケース３０２内部に配設されている一対の超音波送受信部（振動子）３０３、３０４とを備えているものである。以下、図９（ａ）、図１０、図１１（ａ）を用いて、超音波プローブ３０１を用いた「Ｖ透過法」について説明する。まず、図９（ａ）に示したように、超音波送受信部（振動子）３０３において、配管３００底面側へ所定角度で入射するように超音波３０５を発信して配管３００底面において反射させ、受信波３０６として超音波送受信部（振動子）３０４で受信し、順方向応答時間Ｔａを計測する。続いて、流れに対して反対に超音波送受信部（振動子）３０４において、配管３００底面側へ所定角度で入射するように超音波３０７を発信して配管３００底面において反射させ、受信波３０８として超音波送受信部（振動子）３０３で受信し、逆方向応答時間Ｔｂを計測する。このようにして計測された順方向応答時間Ｔａと逆方向応答時間Ｔｂとの伝播時間差Ｔｂ−Ｔａを検出する（図１０参照）。なお、予め、超音波伝播距離Ｌ（＝Ｌ_１＋Ｌ_２）、超音波の入射角度θ（図１１（ａ）参照）は測定しておく。これらのようにして検出した伝播時間差Ｔｂ−Ｔａなどの各値と下記式（１）とを用いて、流速ｖを算出する。 In the “V transmission method”, for example, as shown in FIG. 9A, an ultrasonic probe 301 disposed on the outer surface of the pipe 300 is used. The ultrasonic probe 301 includes a probe case 302 and a pair of ultrasonic transmission / reception units (vibrators) 303 and 304 disposed inside the probe case 302. Hereinafter, the “V transmission method” using the ultrasonic probe 301 will be described with reference to FIGS. 9A, 10, and 11 A. First, as shown in FIG. 9A, in the ultrasonic transmission / reception unit (vibrator) 303, the ultrasonic wave 305 is transmitted so as to be incident on the bottom surface side of the pipe 300 at a predetermined angle and reflected on the bottom surface of the pipe 300, The received wave 306 is received by the ultrasonic transmission / reception unit (vibrator) 304 and the forward response time Ta is measured. Subsequently, in the ultrasonic transmission / reception unit (vibrator) 304 opposite to the flow, the ultrasonic wave 307 is transmitted so as to be incident on the bottom surface side of the pipe 300 at a predetermined angle and reflected on the bottom surface of the pipe 300, and the received wave 308 is obtained. The signal is received by the ultrasonic transmission / reception unit (vibrator) 303, and the reverse response time Tb is measured. A propagation time difference Tb−Ta between the forward response time Ta and the reverse response time Tb measured in this way is detected (see FIG. 10). Note that the ultrasonic propagation distance L (= L ₁ + L ₂ ) and the ultrasonic incident angle θ (see FIG. 11A) are measured in advance. The flow velocity v is calculated using each value such as the propagation time difference Tb-Ta detected as described above and the following equation (1).

ｖ＝Ｌ／２ｃｏｓθ・（Ｔｂ−Ｔａ）／（Ｔａ・Ｔｂ）（１）
ここで、ｖ（ｍ／ｓｅｃ）は流速、Ｌ（ｍ）は超音波送受信部（振動子）３０１、超音波送受信部（振動子）３０２間の超音波伝播距離（図１１（ａ）における距離Ｌ_１と距離Ｌ_２とを加算したもの）、Ｔａ（ｓｅｃ）は順方向応答時間、Ｔｂ（ｓｅｃ）は逆方向応答時間、θ（ｒａｄ）は配管表面を基準とした超音波の入射角度である。 v = L / 2 cos θ · (Tb−Ta) / (Ta · Tb) (1)
Here, v (m / sec) is a flow velocity, and L (m) is an ultrasonic propagation distance (distance in FIG. 11A) between the ultrasonic transmission / reception unit (vibrator) 301 and the ultrasonic transmission / reception unit (vibrator) 302. L ₁ and distance L ₂ ), Ta (sec) is the forward response time, Tb (sec) is the reverse response time, and θ (rad) is the incident angle of the ultrasonic wave with reference to the pipe surface. is there.

上記式（１）は超音波流量計の計測原理として、最もよく使われている伝播時間逆数差法と呼ばれるものであって、音速の項が計算式から除かれている。したがって、上記式（１）を用いれば、一般的に流体の成分、温度、圧力などにより影響を受ける音速が変化しても、流速演算に影響することがないため、安定した計測が可能となる。また、流量は、上記式（１）で算出した流速ｖに配管断面積Ａを乗じることによって、求めることができる（下記式（２）参照）。 The above equation (1) is called a propagation time reciprocal difference method, which is most commonly used as a measurement principle of the ultrasonic flowmeter, and the term of sound velocity is excluded from the calculation formula. Therefore, if the above equation (1) is used, even if the sound speed that is generally affected by the fluid component, temperature, pressure, or the like changes, the flow velocity calculation is not affected, so that stable measurement is possible. . The flow rate can be obtained by multiplying the flow velocity v calculated by the above formula (1) by the pipe cross-sectional area A (see the following formula (2)).

Ｑ＝Ｖ×Ａ（２）
ここで、Ｑ（ｍ^３／ｓ）は流量、Ａ（ｍ^２）は配管の断面積である。 Q = V × A (2)
Here, Q (m ³ / s) is the flow rate, and A (m ² ) is the cross-sectional area of the piping.

一方、「斜め透過法」においては、例えば、図９（ｂ）に示したように、配管３１０の外表面に配設されている超音波プローブ３１１と、超音波プローブ３１１と反対側の配管３１０外表面に配設されている超音波プローブ３１２とが用いられる。なお、超音波プローブ３１１は、プローブケース３１３と、プローブケース３１３内部に配設されている超音波送受信部（振動子）３１４とを備えているものである。超音波プローブ３１２は、プローブケース３１５と、プローブケース３１５内部に配設されている超音波送受信部（振動子）３１６とを備えているものである。以下、図９（ｂ）、図１０、図１１（ｂ）を用いて、超音波プローブ３０１を用いた「Ｖ透過法」について説明する。まず、図９（ｂ）に示したように、超音波送受信部（振動子）３１４において、配管３１０底面側へ所定角度で入射するように超音波３１７を発信して超音波送受信部（振動子）３１６で受信し、順方向応答時間Ｔａを計測する。続いて、流れに対して反対に超音波送受信部（振動子）３１６において、配管３１００上面側へ所定角度で入射するように超音波３１８を発信して超音波送受信部（振動子）３０３で受信し、逆方向応答時間Ｔｂを計測する。このようにして計測された順方向応答時間Ｔａと逆方向応答時間Ｔｂとの伝播時間差Ｔｂ−Ｔａを検出する（図１０参照）。なお、予め、超音波伝播距離Ｌ、超音波の入射角度θ（図１１（ｂ）参照）は測定しておく。これらのようにして検出した時間差Ｔｂ−Ｔａなどの各値と上記式（１）、（２）を用いて、「Ｖ透過法」と同様に、流速Ｖ及び流量Ｑを算出することができる。 On the other hand, in the “oblique transmission method”, for example, as shown in FIG. 9B, the ultrasonic probe 311 disposed on the outer surface of the pipe 310 and the pipe 310 opposite to the ultrasonic probe 311. An ultrasonic probe 312 disposed on the outer surface is used. The ultrasonic probe 311 includes a probe case 313 and an ultrasonic transmission / reception unit (vibrator) 314 disposed inside the probe case 313. The ultrasonic probe 312 includes a probe case 315 and an ultrasonic transmission / reception unit (vibrator) 316 disposed inside the probe case 315. Hereinafter, the “V transmission method” using the ultrasonic probe 301 will be described with reference to FIGS. 9B, 10, and 11 B. First, as shown in FIG. 9B, in the ultrasonic transmission / reception unit (vibrator) 314, an ultrasonic wave 317 is transmitted so as to be incident on the bottom surface side of the pipe 310 at a predetermined angle, and the ultrasonic transmission / reception unit (transducer). ) Receive at 316 and measure forward response time Ta. Subsequently, in the ultrasonic transmitting / receiving unit (vibrator) 316 opposite to the flow, the ultrasonic wave 318 is transmitted so as to be incident on the upper surface side of the pipe 3100 at a predetermined angle and is received by the ultrasonic transmitting / receiving unit (vibrator) 303. Then, the reverse response time Tb is measured. A propagation time difference Tb−Ta between the forward response time Ta and the reverse response time Tb measured in this way is detected (see FIG. 10). Note that the ultrasonic propagation distance L and the ultrasonic incident angle θ (see FIG. 11B) are measured in advance. Using each value such as the time difference Tb−Ta detected as described above and the above formulas (1) and (2), the flow velocity V and the flow rate Q can be calculated in the same manner as the “V transmission method”.

また、「伝搬時間差法」を用いた従来の超音波流量計の他例として、下記特許文献１に開示されているものがある。具体的には、測定経路に設置した超音波送受信器間の被測定流体中に超音波を伝搬させ、その伝搬時間から被測定流体の移動速度を測定する装置であって、第一の超音波プローブの共振周波数と駆動周波数との差が一定となるように周波数コントロール手段によって超音波プローブ駆動周波数をコントロールしているものが開示されている。 Another example of the conventional ultrasonic flowmeter using the “propagation time difference method” is disclosed in Patent Document 1 below. Specifically, an apparatus for propagating ultrasonic waves into a fluid to be measured between ultrasonic transceivers installed in a measurement path and measuring a moving speed of the fluid to be measured from the propagation time, the first ultrasonic wave An ultrasonic probe driving frequency is controlled by frequency control means so that the difference between the resonance frequency of the probe and the driving frequency is constant.

特開平９−３０４１３８号公報JP-A-9-304138

しかしながら、上記特許文献１に代表される従来の超音波流量計において計測感度を高速化させる（分解能を向上させる）と、例えば従来のサンプリング時間（ナノ秒オーダー程度）では問題とならなかった現象が発生した。ここで、該現象について説明する。図１０に示した受信波（超音波）のパルス幅Ｔｗａ又はパルス幅Ｔｗｂは、図１２（ａ）に示すようなものであるが、超音波送受信部（探触子）に温度変化があると、波形の振幅が変化し、結果として到達時間のずれＴ２−Ｔ１（応答時間の基準からの差ΔＴ）が発生する（図１２（ｂ）参照）。なお、パルス幅の実際の波形にはノイズ成分が含まれていることから（図１２（ｂ）参照）、実際には―定電圧Ｖａで波形をとらえることで、パルス波形の応答時間を検出している。 However, when the conventional ultrasonic flowmeter represented by the above-mentioned Patent Document 1 increases the measurement sensitivity (improves the resolution), for example, there is a phenomenon that does not become a problem in the conventional sampling time (on the order of nanoseconds). Occurred. Here, this phenomenon will be described. The pulse width Twa or pulse width Twb of the received wave (ultrasonic wave) shown in FIG. 10 is as shown in FIG. 12A, but when there is a temperature change in the ultrasonic wave transmitting / receiving unit (probe). As a result, the amplitude of the waveform changes, and as a result, a difference in arrival time T2-T1 (difference ΔT from the response time reference) occurs (see FIG. 12B). Since the actual waveform of the pulse width includes a noise component (see FIG. 12B), the response time of the pulse waveform is detected by actually capturing the waveform with the constant voltage Va. ing.

上述したような状況から、従来のサンプリング時間（ナノ秒オーダー程度）で超音波流量計を使用した場合、温度変化があっても基準からの時間に差が生じなかった（図１３（ａ）参照）のが、ピコ秒オーダー程度のサンプリング時間で従来の超音波流量計を使用した場合、計測感度の高速化に伴う温度影響によって、基準からの応答時間が変化してしまう。例えば、同じ流速であるにもかかわらず温度が高くなった場合には、基準からの応答時間が遅くなり（図１３（ｂ）参照）、遅い流速を算出してしまうことになって、実際の流量との測定誤差を発生させてしまうことがあった。 From the situation described above, when the ultrasonic flowmeter was used with the conventional sampling time (on the order of nanoseconds), there was no difference in the time from the reference even if there was a temperature change (see FIG. 13A). However, when a conventional ultrasonic flowmeter is used with a sampling time on the order of picoseconds, the response time from the reference changes due to the temperature effect accompanying the increase in measurement sensitivity. For example, when the temperature becomes high despite the same flow rate, the response time from the reference is delayed (see FIG. 13B), and the slow flow rate is calculated. Measurement errors with the flow rate may occur.

そこで、本発明の目的は、従来よりも計測感度を高速化させた（高分解能）とした場合に発生する測定誤差を最初から発生させないようにする超音波流量計を提供することである。 Accordingly, an object of the present invention is to provide an ultrasonic flowmeter that prevents a measurement error from occurring from the beginning when the measurement sensitivity is made higher (high resolution) than in the past.

（１）本発明の超音波流量計は、ピコ秒オーダーのサンプリング時間での計測が可能なものであって、流体が流通する流路に、前記流体の流れ方向上手側または下手側に向けて超音波を発振することが可能であって、流れ方向上手側または下手側から到来する超音波を受信することが可能な一対の超音波送受信部と、前記一対の超音波送受信部の温度を所定温度に調整する温度調整部と、前記超音波が前記一対の超音波送受信部間を伝搬する時間を計測する時間計測部と、前記時間計測部によって得られた計測結果に基づいて流量を算出する流量算出部と、液体が内部に封入されているととともに、前記一対の超音波送受信部のそれぞれが前記液体に浸漬された状態で収容されている一対の恒温槽と、前記一対の恒温槽内のそれぞれにおいて前記液体に浸漬された状態で収容されている一対のヒーターと、を備えている。また、前記温度調整部が、前記一対の恒温槽のそれぞれの内部において前記液体に浸漬された状態で収容され、前記一対の超音波送受信部のそれぞれの温度を検知可能な一対の温度検知部と、前記一対の温度検知部において検知した前記一対の超音波送受信部のそれぞれの温度に基づいて、前記一対のヒーターのそれぞれの出力を制御する温度制御部と、を有しているものである。
(1) The ultrasonic flowmeter of the present invention is capable of measurement with a sampling time of the order of picoseconds, and is directed toward the upper or lower side of the fluid flow direction in the flow path through which the fluid flows. A pair of ultrasonic transmission / reception units capable of oscillating ultrasonic waves and capable of receiving ultrasonic waves arriving from the upper side or lower side in the flow direction, and the temperature of the pair of ultrasonic transmission / reception units being predetermined A flow rate is calculated based on a temperature adjustment unit that adjusts to a temperature, a time measurement unit that measures a time during which the ultrasonic wave propagates between the pair of ultrasonic transmission / reception units, and a measurement result obtained by the time measurement unit A flow rate calculation unit, a pair of thermostatic chambers in which liquid is enclosed, and the pair of ultrasonic transmission / reception units are accommodated in a state immersed in the liquid, and the pair of thermostatic chambers In each of A pair of heaters housed in a state of being immersed in the liquid . In addition, the temperature adjustment unit is accommodated in the liquid immersed in each of the pair of constant temperature baths, and a pair of temperature detection units capable of detecting the respective temperatures of the pair of ultrasonic transmission / reception units; And a temperature control unit that controls the outputs of the pair of heaters based on the temperatures of the pair of ultrasonic transmission / reception units detected by the pair of temperature detection units .

上記（１）の構成によれば、従来よりも高分解能の超音波流量計とした場合に発生する測定誤差を最初から発生させないようにすることが可能である。すなわち、従来よりも高分解能でありながら、高精度な流量測定が可能な超音波流量計を提供できる。特に、配管を低流速で流れる流体についても高精度な流量測定が可能な超音波流量計を提供できる。 According to the configuration of (1) above, it is possible to prevent a measurement error from occurring from the beginning when an ultrasonic flowmeter with higher resolution than in the past is used. That is, it is possible to provide an ultrasonic flowmeter capable of measuring a flow rate with high accuracy while having a higher resolution than before. In particular, it is possible to provide an ultrasonic flowmeter capable of measuring a flow rate with high accuracy even for a fluid flowing through a pipe at a low flow rate.

（２）別の観点として、本発明の超音波流量計は、ピコ秒オーダーのサンプリング時間での計測が可能なものであって、流体が流通する流路に、前記流体の流れ方向上手側または下手側に向けて超音波を発振することが可能であって、流れ方向上手側または下手側から到来する超音波を受信することが可能な一対の超音波送受信部と、前記超音波が前記一対の超音波送受信部間を伝搬する時間を計測する時間計測部と、前記一対の超音波送受信部のそれぞれが受信した受信波形を、予め基準として得ておいた所定温度の前記一対の超音波送受信部のそれぞれが受信した受信波形に、必要に応じて補正処理する受信波形処理部と、必要に応じて前記受信波形処理部で得られた情報を用いて、前記時間計測部によって得られた情報に基づいて流量を算出する流量算出部と、を備えているものであってもよい。特に、前記受信波形処理部において、前記一対の超音波送受信部のそれぞれが受信した受信波形の波高値の情報と、予め得ておいた所定温度の前記一対の超音波送受信部のそれぞれが受信した受信波形の波高値の情報と、前記時間計測部で得られた時間の情報と、温度が高くなるほど超音波の受信波形の波高値が低くなるという受信波形の波高値の温度依存特性の情報と、に基づいて、前記補正処理を行うものであってもよい。
(2) As another aspect, the ultrasonic flowmeter of the present invention is capable of measurement with a sampling time of the order of picoseconds, and is arranged on the upper side of the fluid flow direction or in the flow path through which the fluid flows. A pair of ultrasonic transmission / reception units capable of oscillating ultrasonic waves toward the lower side and receiving ultrasonic waves coming from the upper side or lower side in the flow direction; and The pair of ultrasonic transmission / reception at a predetermined temperature, which is obtained in advance as a reference from the reception waveform received by each of the pair of ultrasonic transmission / reception units and the time measurement unit that measures the time to propagate between the ultrasonic transmission / reception units Information obtained by the time measuring unit using the received waveform processing unit that performs correction processing on the received waveform received by each of the units, and information obtained by the received waveform processing unit as necessary Based on flow rate And a flow rate calculation unit that calculates. In particular, in the reception waveform processing unit, information on the peak value of the reception waveform received by each of the pair of ultrasonic transmission / reception units and each of the pair of ultrasonic transmission / reception units having a predetermined temperature obtained in advance are received. Information on the peak value of the received waveform, information on the time obtained by the time measuring unit, and information on the temperature-dependent characteristics of the peak value of the received waveform that the peak value of the received waveform of the ultrasonic wave becomes lower as the temperature increases. , The correction process may be performed.

上記（２）の構成によれば、簡易な構成でありながら、従来よりも高分解能の超音波流量計とした場合に発生する測定誤差を最初から発生させないようにすることが可能である。すなわち、従来よりも高分解能でありながら、高精度な流量測定が可能な超音波流量計を提供できる。特に、配管を低流速で流れる流体についても高精度な流量測定が可能な超音波流量計を提供できる。また、上記（１）の超音波流量計においては、超音波送受信部の温度が予め定めた基準となる所定温度になるまで測定を待機する必要があるのに対し、上記（２）の構成によれば、最初に一度又は定期的に、予め基準として所定温度の一対の超音波送受信部のそれぞれが受信した受信波形を得ておけば、異なる場所の配管における流量測定を即時に行うことができるので、異なる場所で多数の測定を短時間且つ高精度で行うことが可能であり、様々な場所で行う流量測定の全体作業効率を向上させることが可能となる。
According to the configuration (2), it is possible to prevent a measurement error from occurring from the beginning when the ultrasonic flowmeter has a higher resolution than the conventional one , although it is a simple configuration . That is, it is possible to provide an ultrasonic flowmeter capable of measuring a flow rate with high accuracy while having a higher resolution than before. In particular, it is possible to provide an ultrasonic flowmeter capable of measuring a flow rate with high accuracy even for a fluid flowing through a pipe at a low flow rate. Further, in the ultrasonic flowmeter of (1), it is necessary to wait for the measurement until the temperature of the ultrasonic transmission / reception unit reaches a predetermined temperature that is a predetermined reference, whereas the configuration of (2) is used. According to the above, once the received waveform received by each of the pair of ultrasonic transmission / reception units having a predetermined temperature as a reference is obtained once or periodically in advance, flow rate measurement in pipes at different locations can be immediately performed. Therefore, it is possible to perform a large number of measurements at different locations in a short time and with high accuracy, and it is possible to improve the overall work efficiency of the flow rate measurement performed at various locations.

（３）上記（２）の超音波流量計においては、前記超音波送受信部から検出した受信波形の情報について、予め前記超音波送受信部から取得しておいた所定温度毎の受信波形の情報のうちいずれの情報に合致するか判定し、前記所定温度毎の受信波形の情報のうち合致した受信波形における温度を、流路内を流れる流体の温度として検出する温度検出部を有しているものであってもよい。
( 3 ) In the ultrasonic flowmeter of (2) above, the received waveform information detected from the ultrasonic transmission / reception unit is received from the ultrasonic transmission / reception unit in advance. A temperature detection unit that determines which information matches and detects the temperature of the received waveform that matches the received waveform information for each predetermined temperature as the temperature of the fluid flowing in the flow path It may be.

上記（３）の構成によれば、流体の流量を測定できるだけでなく、流体の温度検出も可能である。
According to the configuration ( 3 ) above, not only the flow rate of the fluid can be measured, but also the temperature of the fluid can be detected.

本発明の第１実施形態に係る超音波流量計の概略構成図である。1 is a schematic configuration diagram of an ultrasonic flowmeter according to a first embodiment of the present invention. 本発明の第２実施形態に係る超音波流量計の概略構成図である。It is a schematic block diagram of the ultrasonic flowmeter which concerns on 2nd Embodiment of this invention. 本発明の実施例１における調査に用いた装置構成の概略構成図である。It is a schematic block diagram of the apparatus structure used for the investigation in Example 1 of this invention. （ａ）が本発明の実施例１に係るグラフであって、超音波流量計における超音波送受信部（振動子）の温度（８℃〜１８℃）と応答時間の基準からの差との相関関係を示すもの、（ｂ）が本発明の実施例２に係るグラフであって、（ａ）とは別の超音波流量計における超音波送受信部（振動子）の温度（２０℃〜６５℃）と応答時間差との相関関係を示すものである。(A) is a graph which concerns on Example 1 of this invention, Comprising: Correlation with the temperature (8 degreeC-18 degreeC) of the ultrasonic transmission-and-reception part (vibrator) in an ultrasonic flowmeter, and the difference from the reference | standard of a response time (B) is the graph which concerns on Example 2 of this invention, Comprising: The temperature (20 degreeC-65 degreeC) of the ultrasonic transmission-and-reception part (vibrator) in the ultrasonic flowmeter different from (a) ) And the response time difference. 本発明の実施例２における調査に用いた装置構成の概略構成図である。It is a schematic block diagram of the apparatus structure used for the investigation in Example 2 of this invention. 本発明の実施例２での測定結果に係るグラフであって、（ａ）が超音波受信部（振動子）の温度を１０℃とした場合における超音波の受信波形の測定結果を示すもの、（ｂ）が超音波受信部（振動子）の温度を４０℃とした場合における超音波の受信波形の測定結果を示すものである。It is a graph which concerns on the measurement result in Example 2 of this invention, Comprising: (a) shows the measurement result of the received waveform of an ultrasonic wave when the temperature of an ultrasonic receiving part (vibrator) is 10 degreeC, (B) shows the measurement result of the received waveform of the ultrasonic wave when the temperature of the ultrasonic wave receiving unit (vibrator) is 40 ° C. 本発明の実施例２に係るグラフであって、受信波の波高値と温度との相関関係を示したものである。It is a graph which concerns on Example 2 of this invention, Comprising: The correlation with the peak value of a received wave and temperature is shown. 本発明の実施例３に係る超音波流量計についての動作確認実験結果（温度変化と流速との相関関係）を示したグラフである。It is the graph which showed the operation | movement confirmation experiment result (correlation with a temperature change and a flow velocity) about the ultrasonic flowmeter which concerns on Example 3 of this invention. 従来の超音波流量計の概略構成図であって、（ａ）が測定原理にＶ透過法を用いたもの、（ｂ）が測定原理に斜め透過法を用いたものである。It is a schematic block diagram of the conventional ultrasonic flowmeter, (a) uses the V transmission method for the measurement principle, (b) uses the oblique transmission method for the measurement principle. 図９（ａ）、（ｂ）に示した超音波流量計の計測原理を説明するためのタイムチャートである。It is a time chart for demonstrating the measurement principle of the ultrasonic flowmeter shown to Fig.9 (a), (b). （ａ）が図９（ａ）に示した超音波流量計の計測原理を説明するための概略図、（ｂ）が図９（ｂ）に示した超音波流量計の計測原理を説明するための概略図である。9A is a schematic diagram for explaining the measurement principle of the ultrasonic flow meter shown in FIG. 9A, and FIG. 9B is a diagram for explaining the measurement principle of the ultrasonic flow meter shown in FIG. 9B. FIG. パルス幅の温度影響を説明するためのグラフであって、（ａ）がパルス幅、（ｂ）が実際のパルス波形である。It is a graph for demonstrating the temperature influence of a pulse width, (a) is a pulse width, (b) is an actual pulse waveform. 温度によるパルス幅の変化を示すグラフであって、（ａ）がサンプリング時間をナノ秒オーダー程度とした場合のもの、（ｂ）がサンプリング時間をピコ秒オーダー程度とした場合のものである。It is a graph which shows the change of the pulse width by temperature, Comprising: (a) is a thing when sampling time is set to about nanosecond order, (b) is a thing when sampling time is set to about picosecond order.

＜第１実施形態＞
以下、図面を参照しながら、本発明の第１実施形態に係る超音波流量計について説明する。 <First Embodiment>
Hereinafter, an ultrasonic flowmeter according to a first embodiment of the present invention will be described with reference to the drawings.

図１に示すように、本実施形態に係る超音波流量計１００は、流体が流通する測定経路（流路）１に着脱可能な第一の超音波送受信部２及び第二の超音波送受信部３と、第一の超音波送受信部２を内部に収容している第一の恒温槽４と、第二の超音波送受信部３を内部に収容している第二の恒温槽５と、第一の超音波送受信部２の温度を検知可能な第一の温度検知部８と、第二の超音波送受信部３の温度を検知可能な第二の温度検知部９と、第一のヒーター６及び第二のヒーター７を制御可能な温度制御部１０と、所定部位の制御等を行う制御部１１と、を備えているものである。 As shown in FIG. 1, the ultrasonic flowmeter 100 according to the present embodiment includes a first ultrasonic transmission / reception unit 2 and a second ultrasonic transmission / reception unit that can be attached to and detached from a measurement path (flow channel) 1 through which a fluid flows. 3, a first thermostatic chamber 4 that houses the first ultrasonic transmission / reception unit 2, a second thermostatic bath 5 that houses the second ultrasonic transmission / reception unit 3, The first temperature detection unit 8 capable of detecting the temperature of one ultrasonic transmission / reception unit 2, the second temperature detection unit 9 capable of detecting the temperature of the second ultrasonic transmission / reception unit 3, and the first heater 6 And the temperature control part 10 which can control the 2nd heater 7, and the control part 11 which controls a predetermined part etc. are provided.

第一の超音波送受信部２及び第二の超音波送受信部３のそれぞれは、発振回路（図示せず）によって駆動し、測定経路１内部の流体の流れ方向上手側または下手側に向けて超音波を発生することができるものである。また、第一の超音波送受信部２及び第二の超音波送受信部３のそれぞれは、流れ方向上手側または下手側から到来した超音波を受信できるものでもある。 Each of the first ultrasonic transmission / reception unit 2 and the second ultrasonic transmission / reception unit 3 is driven by an oscillation circuit (not shown) and is superposed toward the upper side or lower side in the fluid flow direction in the measurement path 1. A sound wave can be generated. In addition, each of the first ultrasonic transmission / reception unit 2 and the second ultrasonic transmission / reception unit 3 can receive ultrasonic waves coming from the upper side or the lower side in the flow direction.

第一の恒温槽４及び第二の恒温槽５の内部には液体が封入されており、第一のヒーター６及び第二のヒーター７において発生した熱を、間接的に第一の超音波送受信部２及び第二の超音波送受信部３のそれぞれに伝導することができるようになっている。 The first thermostat 4 and the second thermostat 5 are filled with liquid, and the heat generated in the first heater 6 and the second heater 7 is indirectly transmitted to the first ultrasonic wave. It is possible to conduct to each of the unit 2 and the second ultrasonic transmission / reception unit 3.

第一の温度検知部８は、第一の恒温槽４の内部を加熱可能な第一のヒーター６と、第一の超音波送受信部２の温度検知に用いる温度検知素子（図示せず）とを、第一の恒温槽４の内部に有している。同様に、第二の温度検知部９は、第二の恒温槽５の内部を加熱可能な第二のヒーター７と、第二の超音波送受信部３の温度検知に用いる温度検知素子（図示せず）とを、第二の恒温槽５の内部に有している。 The first temperature detection unit 8 includes a first heater 6 capable of heating the inside of the first thermostat 4, a temperature detection element (not shown) used for temperature detection of the first ultrasonic transmission / reception unit 2, and In the first thermostat 4. Similarly, the second temperature detection unit 9 includes a second heater 7 capable of heating the inside of the second thermostat 5 and a temperature detection element (not shown) used for temperature detection of the second ultrasonic transmission / reception unit 3. In the second thermostatic chamber 5.

温度制御部１０は、第一の温度検知部８及び第二の温度検知部９において検知した第一の超音波送受信部２及び第二の超音波送受信部３の温度に基づいて、第一のヒーター６及び第二のヒーター７の出力を制御するものである。 Based on the temperature of the first ultrasonic transmission / reception unit 2 and the second ultrasonic transmission / reception unit 3 detected by the first temperature detection unit 8 and the second temperature detection unit 9, the temperature control unit 10 The outputs of the heater 6 and the second heater 7 are controlled.

なお、第一の温度検知部８、第二の温度検知部９、及び、温度制御部１０は、第一の超音波送受信部２及び第二の超音波送受信部３の温度を所定温度に調整する温度調整部の主要部を構成している。 In addition, the 1st temperature detection part 8, the 2nd temperature detection part 9, and the temperature control part 10 adjust the temperature of the 1st ultrasonic transmission / reception part 2 and the 2nd ultrasonic transmission / reception part 3 to predetermined temperature. This constitutes the main part of the temperature adjustment unit.

制御部１１は、超音波が第一の超音波送受信部２、第二の超音波送受信部３間を伝搬する時間を計測する時間計測部１２と、時間計測部１２によって得られた計測結果に基づいて流量を算出する流量算出部１３とを有しているものである。 The control unit 11 includes a time measurement unit 12 that measures the time during which the ultrasonic wave propagates between the first ultrasonic transmission / reception unit 2 and the second ultrasonic transmission / reception unit 3, and the measurement result obtained by the time measurement unit 12. It has a flow rate calculation unit 13 that calculates a flow rate based on it.

次に、超音波流量計１００の動作について説明する。まず、第一の温度検知部８及び第二の温度検知部９において、測定経路１外表面に取り付けられた第一の超音波送受信部２及び第二の超音波送受信部３の温度をそれぞれ検知する。次に、検知した該温度に基づいて、温度制御部１０は、第一の超音波送受信部２及び第二の超音波送受信部３の温度が予め定めた所定温度（例えば、温度変化による測定誤差が生じないように予め定めた基準温度）となるように、第一のヒーター６及び第二のヒーター７の出力を制御し、第一の恒温槽４及び第二の恒温槽５の内部における液体を介して第一の超音波送受信部２及び第二の超音波送受信部３の温度調整を行う。続いて、第一の超音波送受信部２及び第二の超音波送受信部３が所定温度になった後、測定経路１内部に流体が流れている状態において、第一の超音波送受信部２及び第二の超音波送受信部３のそれぞれから超音波を送信し、第一の超音波送受信部２及び第二の超音波送受信部３は相互に受信波を受信する。このとき、時間計測部１２によって、第一の超音波送受信部２及び第二の超音波送受信部３のそれぞれから送信された超音波が、第一の超音波送受信部２、第二の超音波送受信部３間を伝搬する時間を計測しておく。そして、流量算出部１３において、時間計測部１２によって得られた計測結果と、上記式（１）と、上記式（１）に代入するために予め得ておいた各値とを用いて流量を算出する。 Next, the operation of the ultrasonic flowmeter 100 will be described. First, in the first temperature detection unit 8 and the second temperature detection unit 9, the temperatures of the first ultrasonic transmission / reception unit 2 and the second ultrasonic transmission / reception unit 3 attached to the outer surface of the measurement path 1 are detected, respectively. To do. Next, based on the detected temperature, the temperature control unit 10 determines the temperature of the first ultrasonic transmission / reception unit 2 and the second ultrasonic transmission / reception unit 3 at a predetermined temperature (for example, a measurement error due to a temperature change). The output of the first heater 6 and the second heater 7 is controlled so that the liquid is in the first thermostat 4 and the second thermostat 5 so that the liquid is in the first thermostat 4 and the second thermostat 5. The temperature of the first ultrasonic transmission / reception unit 2 and the second ultrasonic transmission / reception unit 3 is adjusted via the. Subsequently, after the first ultrasonic transmission / reception unit 2 and the second ultrasonic transmission / reception unit 3 reach a predetermined temperature, the first ultrasonic transmission / reception unit 2 and the fluid are flowing in the measurement path 1. Ultrasonic waves are transmitted from each of the second ultrasonic transmission / reception units 3, and the first ultrasonic transmission / reception unit 2 and the second ultrasonic transmission / reception unit 3 receive reception waves from each other. At this time, the ultrasonic waves transmitted from the first ultrasonic transmission / reception unit 2 and the second ultrasonic transmission / reception unit 3 by the time measurement unit 12 are converted into the first ultrasonic transmission / reception unit 2 and the second ultrasonic wave, respectively. The time for propagation between the transmission / reception units 3 is measured. Then, in the flow rate calculation unit 13, the flow rate is calculated using the measurement result obtained by the time measurement unit 12, the above formula (1), and each value obtained in advance for substitution into the above formula (1). calculate.

本実施形態によれば、第一の超音波送受信部２及び第二の超音波送受信部３を、予め定めた所定温度、例えば、温度変化による測定誤差が生じないように予め定めた基準温度に調整できるので、従来よりも高分解能の超音波流量計とした場合に発生する測定誤差を最初から発生させないようにすることが可能である。すなわち、従来よりも高分解能でありながら、高精度な流量測定が可能な超音波流量計１００を提供できる。 According to this embodiment, the first ultrasonic transmission / reception unit 2 and the second ultrasonic transmission / reception unit 3 are set to a predetermined temperature, for example, a predetermined reference temperature so as not to cause a measurement error due to a temperature change. Since it can be adjusted, it is possible to prevent a measurement error from occurring from the beginning when the ultrasonic flowmeter has a higher resolution than in the past. That is, it is possible to provide the ultrasonic flowmeter 100 capable of measuring the flow rate with high accuracy while having a higher resolution than before.

＜第２実施形態＞
次に、本発明の第２実施形態に係る超音波流量計について説明する。なお、本実施形態における符合２０、２３、２４の部位は、順に、第１実施形態における符合１、２、３の部位と同様であるので、説明を省略することがある。 Second Embodiment
Next, an ultrasonic flowmeter according to a second embodiment of the present invention will be described. In addition, since the site | part of the codes | symbols 20, 23, and 24 in this embodiment are the same as that of the codes | symbols 1, 2, and 3 in 1st Embodiment in order, description may be abbreviate | omitted.

図２に示すように、本実施形態に係る超音波流量計２００は、流体が流通する測定経路である配管（流路）２０に着脱可能な超音波プローブ２１と、超音波プローブ２１と接続されている制御部３０とを備え、上述した「Ｖ透過法」と呼ばれる測定方法を用いるものである。 As shown in FIG. 2, an ultrasonic flowmeter 200 according to this embodiment is connected to an ultrasonic probe 21 that can be attached to and detached from a pipe (flow path) 20 that is a measurement path through which a fluid flows, and the ultrasonic probe 21. And a control method called the “V transmission method” described above.

超音波プローブ２１は、プローブケース２２と、プローブケース２２内部の別室にそれぞれ配設されている超音波送受信部（振動子）２３、２４とを備えているものである。 The ultrasonic probe 21 includes a probe case 22 and ultrasonic transmission / reception units (vibrators) 23 and 24 disposed in separate chambers inside the probe case 22.

制御部３０は、送信波発振部３１と、受信部３２と、フィルタ部３３と、増幅部３４と、正規化部３５と、高速演算部３６と、流量算出部３７と、ＣＰＵ３７と、を有している。また、制御部３０は、上記符号３１〜３５の部位と順に同様の送信波発振部３９、受信部４０、フィルタ部４１、増幅部４２、正規化部４３、を有している。 The control unit 30 includes a transmission wave oscillation unit 31, a reception unit 32, a filter unit 33, an amplification unit 34, a normalization unit 35, a high-speed calculation unit 36, a flow rate calculation unit 37, and a CPU 37. doing. Further, the control unit 30 includes a transmission wave oscillating unit 39, a receiving unit 40, a filter unit 41, an amplifying unit 42, and a normalizing unit 43 that are similar to the parts 31 to 35 described above.

送信波発振部３１、３９は、ＣＰＵ３７から発せられた発振開始信号によって、超音波送受信部（振動子）２３、２４を駆動し、超音波２５、２７を発生させるものである。 The transmission wave oscillating units 31 and 39 are configured to drive the ultrasonic transmission / reception units (vibrators) 23 and 24 by the oscillation start signal generated from the CPU 37 and generate the ultrasonic waves 25 and 27.

超音波送受信部（振動子）２３、２４は、図２に示したように、超音波２５、２７を発生した後、超音波２５、２７が測定経路（流路）２０の底部で反射してなる受信波２６、２８をそれぞれ受信することができるものである。 As shown in FIG. 2, the ultrasonic transmission / reception units (vibrators) 23 and 24 generate ultrasonic waves 25 and 27, and then the ultrasonic waves 25 and 27 are reflected from the bottom of the measurement path (flow path) 20. The received waves 26 and 28 can be received, respectively.

受信部３２は、超音波送受信部（振動子）２４で受信した受信波２８の信号を検出する回路（図示せず）を有しているものである。同様に、受信部４０は、超音波送受信部（振動子）２４で受信した受信波２６の信号を検出する回路（図示せず）を有しているものである。 The receiving unit 32 includes a circuit (not shown) that detects a signal of the received wave 28 received by the ultrasonic transmitting / receiving unit (vibrator) 24. Similarly, the receiving unit 40 includes a circuit (not shown) that detects a signal of the received wave 26 received by the ultrasonic transmitting / receiving unit (vibrator) 24.

フィルタ部３３、４１は、入力された電気信号に帯域制限をかけたり、特定の周波数成分を取り出したりすることが可能なフィルタ回路を有しているものである。 The filter units 33 and 41 have a filter circuit capable of band-limiting the input electric signal and extracting a specific frequency component.

増幅部３４、４２は、フィルタ部３３、４１から出力された信号を増幅する増幅回路を有しているものである。 The amplification units 34 and 42 have amplification circuits that amplify the signals output from the filter units 33 and 41.

正規化部３５は、増幅部３４から出力された信号を正規化し、正規化パルスを生成する正規化回路（図示せず）と、増幅部３４から出力された信号と基準電圧または基準電流とを比較し、どちらが大きいかで出力が切り替わるコンパレータとを有しているものである。同様に、正規化部４３は、増幅部４２から出力された信号を正規化し、正規化パルスを生成する正規化回路（図示せず）と、増幅部４２から出力された信号と基準電圧または基準電流とを比較し、どちらが大きいかで出力が切り替わるコンパレータとを有しているものである。なお、正規化部３５、４３は、後述する高速演算部３６、補正処理部３７ｂなどとともに、受信波形処理部（図示せず）の主要部を構成するものでもある。 The normalization unit 35 normalizes the signal output from the amplification unit 34 and generates a normalization pulse (not shown), and the signal output from the amplification unit 34 and the reference voltage or reference current. The comparator has a comparator that switches the output depending on which is larger. Similarly, the normalization unit 43 normalizes the signal output from the amplification unit 42 and generates a normalization pulse, and the signal output from the amplification unit 42 and the reference voltage or reference It has a comparator that compares the current and switches the output depending on which is larger. In addition, the normalization parts 35 and 43 comprise the main part of a received waveform processing part (not shown) with the high-speed calculating part 36, the correction process part 37b, etc. which are mentioned later.

高速演算部３６は、正規化部３５、４３から出力された正規化パルス信号を受信し、正規化パルスの計測を行うものである。 The high-speed computing unit 36 receives the normalized pulse signal output from the normalizing units 35 and 43 and measures the normalized pulse.

ＣＰＵ３７は、時間計測部３７ａと流量算出部３７ｂとを有している。時間計測部３７ａは、送信波発振部３１、３９のそれぞれに超音波の発振開始信号が送信されてから予め設定された一定時間経過後の基準時間から、各正規化パルスの信号を検出するまでの時間を各応答時間として計測するものである。流量算出部３７ｂは、補正処理部３７ａ１で補正処理された応答時間差の値と上記式（１）、（２）とを用いて流体の流速及び流量を算出する処理を行うものである。 The CPU 37 includes a time measurement unit 37a and a flow rate calculation unit 37b. The time measuring unit 37a detects each normalized pulse signal from a reference time after a predetermined time has elapsed after the ultrasonic oscillation start signal is transmitted to each of the transmission wave oscillating units 31 and 39. Is measured as each response time. The flow rate calculation unit 37b performs a process of calculating the flow velocity and flow rate of the fluid using the response time difference value corrected by the correction processing unit 37a1 and the above equations (1) and (2).

なお、補正処理部３７ａ１における温度に対する応答時間差の補正処理は、例えば、実際の測定前に、使用する超音波流量計ごとに予め求めておいた下記式（３）のうちいずれか一つを用いて行う。ここで、下記式（３）におけるｙは補正時間（ｎｓ）、ｘは温度（℃）である。なお、下記式（３）の求め方は、後述する本発明の実施例において説明する。ここで、上記補正に用いる式については、下記式（３）に限られず、一次関数、二次関数、指数関数、対数関数、多項式など各種の近似式で表すこともできるが、最も高い相関関係を有した近似式を用いることが好ましい。 In addition, the correction processing of the response time difference with respect to the temperature in the correction processing unit 37a1 uses, for example, any one of the following formula (3) obtained in advance for each ultrasonic flowmeter to be used before actual measurement. Do it. Here, y in the following formula (3) is a correction time (ns), and x is a temperature (° C.). In addition, the method of calculating | requiring following formula (3) is demonstrated in the Example of this invention mentioned later. Here, the formula used for the correction is not limited to the following formula (3), but can be expressed by various approximate expressions such as a linear function, a quadratic function, an exponential function, a logarithmic function, a polynomial, etc., but the highest correlation It is preferable to use an approximate expression having

ｙ＝０．２０８ｘ＋２．３０６（３） y = 0.208x + 2.306 (3)

また、図１２（ｂ）に示したように、超音波の受信波形の波高値は、温度が高くなるほど波高値が低くなるという温度依存特性を示す。ここで、該波高値と温度との相関関係を予め検出しておき、正規化部３５、４３において、例えば、該相関関係から得られる下記式（４）を用いて、受信波形の波高値から温度データを算出し、上記式（３）のうち用いる方に入力することで温度補正処理を行うこととしてもよい。ここで、下記式（４）におけるｙ_１はエコー電圧（ｍＶ）、ｘ_１は温度（℃）である。このような補正処理を行えば、温度計などを用いた別途の温度検出を不要とすることができる。なお、下記式（４）の求め方は、後述する本発明の実施例において説明する。 Further, as shown in FIG. 12B, the peak value of the received waveform of the ultrasonic wave shows a temperature dependence characteristic that the peak value becomes lower as the temperature becomes higher. Here, the correlation between the peak value and the temperature is detected in advance, and the normalizing units 35 and 43 use, for example, the following formula (4) obtained from the correlation to calculate the peak value of the received waveform. Temperature correction processing may be performed by calculating temperature data and inputting the temperature data to the one used in the above formula (3). Here, y ₁ in the following formula (4) is an echo voltage (mV), and x ₁ is a temperature (° C.). If such correction processing is performed, separate temperature detection using a thermometer or the like can be eliminated. In addition, the method of calculating | requiring following formula (4) is demonstrated in the Example of this invention mentioned later.

ｙ_１＝−０.２３２７ｘ_１ ^２＋２.１８５５ｘ＋１３０７.６（４） y ₁ = −0.2327x ₁ ² + 2.1855x + 1307.6 (4)

次に、超音波流量計２００の動作について説明する。まず、ＣＰＵ３７から送信波発信部３１、３９に発振開始信号を発すると同時に、受信部３２、４０の時間計測部３２ａ、４０ａに時間計測開始信号を送信する。ＣＰＵ３７から発信開始信号を受信した送信波発信部３１、３９は、超音波送受信部（振動子）２３、２４を駆動して、超音波２５、２７（図２参照）を発生させる。一方、時間計測開始信号を受信した時間計測部３２ａ、４０ａは、時間計測を開始する。次に、超音波送受信部（振動子）２３、２４において、超音波２５、２７が反射してなる受信波２８、２６を受信し、送信波発信部３１、３９を介して受信信号を受信部３２、４０に送信する。このとき、時間計測部３２ａ、４０ａは、時間計測を終了し、時間計測結果信号を受信信号とともに、フィルタ部３３、４１に出力する。フィルタ部３３、４１から受信した信号を増幅部３４、４２によって増幅した後、正規化部３５、４３に信号を送信する。信号を受信した正規化部３５、４３は、温度に対する応答時間差の補正処理を行うとともに増幅部３４から出力された信号を正規化し、正規化パルスを生成する。このとき、正規化部３５、４３内のコンパレータによって、増幅部３４から出力された信号と基準電圧とを比較し、増幅部３４から出力された信号が基準電圧よりも大きい場合、正規化パルス信号が高速演算部３６に出力される。正規化パルス信号を受信した高速演算部３６は、ＣＰＵ３７で設定した基準時間から数マイクロ秒の時間範囲をピコ秒オーダー（例えば、６５ピコ秒）毎に正規化パルスの計測を行う。そして、高速演算部３６からの正規化パルスの計測結果の信号を受信した流量算出部３７は、流体の流速及び流量を算出する処理を行う。 Next, the operation of the ultrasonic flowmeter 200 will be described. First, the CPU 37 issues an oscillation start signal to the transmission wave transmitters 31 and 39, and simultaneously transmits the time measurement start signal to the time measuring units 32a and 40a of the receivers 32 and 40. The transmission wave transmission units 31 and 39 that have received the transmission start signal from the CPU 37 drive the ultrasonic transmission / reception units (vibrators) 23 and 24 to generate the ultrasonic waves 25 and 27 (see FIG. 2). On the other hand, the time measurement units 32a and 40a that have received the time measurement start signal start time measurement. Next, the ultrasonic transmission / reception units (vibrators) 23 and 24 receive the reception waves 28 and 26 reflected by the ultrasonic waves 25 and 27, and receive the reception signals via the transmission wave transmission units 31 and 39. 32, 40. At this time, the time measurement units 32a and 40a end the time measurement, and output the time measurement result signal to the filter units 33 and 41 together with the reception signal. After the signals received from the filter units 33 and 41 are amplified by the amplification units 34 and 42, the signals are transmitted to the normalization units 35 and 43. The normalization units 35 and 43 that have received the signal perform a correction process of the response time difference with respect to the temperature, normalize the signal output from the amplification unit 34, and generate a normalization pulse. At this time, the comparators in the normalizing units 35 and 43 compare the signal output from the amplifying unit 34 with the reference voltage. If the signal output from the amplifying unit 34 is greater than the reference voltage, the normalized pulse signal Is output to the high-speed calculation unit 36. Receiving the normalized pulse signal, the high-speed computing unit 36 measures the normalized pulse every picosecond order (for example, 65 picoseconds) from the reference time set by the CPU 37 to several microseconds. Then, the flow rate calculation unit 37 that has received the signal of the measurement result of the normalized pulse from the high-speed calculation unit 36 performs a process of calculating the fluid flow velocity and flow rate.

上記構成によれば、温度変化による超音波の応答時間差を補正できるので、従来よりも高分解能の超音波流量計とした場合に発生する測定誤差を最初から発生させないようにすることが可能である。すなわち、従来よりも高分解能でありながら、高精度な流量測定が可能な超音波流量計２００を提供できる。また、上記第１実施形態の超音波流量計１００においては、超音波送受信部２２、２３の温度が予め定めた基準となる所定温度になるまで測定を待機する必要があるのに対し、本実施形態によれば、最初に一度又は定期的に、予め基準として所定温度の超音波送受信部２２及び超音波送受信部２３のそれぞれが受信した受信波形を得ておけば、異なる場所の配管における流量測定を即時に行うことができるので、異なる場所で多数の測定を短時間且つ高精度で行うことが可能であり、様々な場所で行う流量測定の全体作業効率を向上させることが可能となる。 According to the above configuration, since the difference in the response time of the ultrasonic wave due to the temperature change can be corrected, it is possible to prevent a measurement error that occurs when the ultrasonic flowmeter has a higher resolution than the conventional one from the beginning. . That is, it is possible to provide the ultrasonic flowmeter 200 capable of measuring the flow rate with high accuracy while having a higher resolution than before. Further, in the ultrasonic flow meter 100 of the first embodiment, it is necessary to wait for the measurement until the temperature of the ultrasonic transmission / reception units 22 and 23 reaches a predetermined temperature that is a predetermined reference, whereas the present embodiment According to the form, if the reception waveform received by each of the ultrasonic transmission / reception unit 22 and the ultrasonic transmission / reception unit 23 at a predetermined temperature is obtained as a reference in advance once or periodically, the flow measurement in pipes at different locations is obtained. Therefore, it is possible to perform a large number of measurements at different locations in a short time and with high accuracy, and it is possible to improve the overall working efficiency of the flow rate measurement performed at various locations.

（実施例１）
ここで、上述の第２実施形態における補正の式（３）の算出方法について説明する。具体的には、上述の第２実施形態と同様の超音波流量計について、超音波送受信部（振動子）の温度（８℃〜１８℃の範囲）と応答時間差との相関関係を調査して、算出した。以下に、該調査に用いた装置構成について説明する。 Example 1
Here, a calculation method of the correction formula (3) in the second embodiment will be described. Specifically, for the same ultrasonic flowmeter as in the second embodiment described above, the correlation between the temperature of the ultrasonic transmission / reception unit (vibrator) (range of 8 ° C. to 18 ° C.) and the response time difference was investigated. Calculated. The apparatus configuration used for the investigation will be described below.

図３に示したように、恒温槽５０と、恒温槽５０の内部に設けられた水槽５１と、水槽５１の底部に設けられた固定冶具５２と、水槽５１内の水温計測に用いるＫ型熱電対５３に接続された温度計５４と、本発明に係る超音波流量計と、を備えた実験装置を用いて調査した。なお、本発明に係る超音波流量計は、第２実施形態の制御部３０（図２参照）と同様の制御部６０と、固定冶具５２の内側において対向するように且つ互いに超音波の送受信ができるように任意の距離を離して設けられた一対の超音波送受信部６１、６２（超音波プローブ）とを有している。また、制御部６０及び温度計５４で検出されたデータは、記憶部（図示せず）において蓄積されるようになっている。 As shown in FIG. 3, the thermostat 50, the water tank 51 provided in the thermostat 50, the fixed jig 52 provided at the bottom of the water tank 51, and the K-type thermoelectric used for measuring the water temperature in the water tank 51. An investigation was performed using an experimental apparatus including a thermometer 54 connected to the pair 53 and the ultrasonic flowmeter according to the present invention. The ultrasonic flowmeter according to the present invention transmits and receives ultrasonic waves so as to face each other inside the fixing jig 52 and the control unit 60 similar to the control unit 30 (see FIG. 2) of the second embodiment. It has a pair of ultrasonic transmission / reception units 61 and 62 (ultrasonic probes) provided at an arbitrary distance so as to be able to do so. Further, data detected by the control unit 60 and the thermometer 54 is accumulated in a storage unit (not shown).

次に、上記装置を用いた応答時間差の調査方法を示す。恒温槽５０において、水槽５１内の水温を５℃〜２０℃に徐々に変化させるように制御することによって、超音波送受信部６１、６２の温度を経時的に変化させつつ８℃〜１８℃までの範囲で、第２実施形態の動作と同様に超音波の送受信を行った際のＫ型熱電対５４による水温のデータと、第２実施形態の動作と同様にして制御部６０で得た応答時間差のデータとを検出して、調査した。なお、水温と超音波送受信部６１、６２の温度とが十分に一致するようにしてから、調査は行った。このようにして得られたデータから作成した超音波送受信部（振動子）の温度（８℃〜１８℃の範囲）と応答時間差ΔＴとの相関関係を図４に示す。 Next, a method for investigating the response time difference using the above apparatus will be described. In the thermostat 50, by controlling the water temperature in the water tank 51 to be gradually changed from 5 ° C. to 20 ° C., the temperature of the ultrasonic transmission / reception units 61 and 62 is changed over time to 8 ° C. to 18 ° C. In the range, the data of the water temperature by the K-type thermocouple 54 when the ultrasonic wave is transmitted / received similarly to the operation of the second embodiment, and the response obtained by the control unit 60 similarly to the operation of the second embodiment Time difference data was detected and investigated. The investigation was performed after the water temperature and the temperature of the ultrasonic transmission / reception units 61 and 62 sufficiently matched. FIG. 4 shows the correlation between the temperature (range of 8 ° C. to 18 ° C.) of the ultrasonic transmission / reception unit (vibrator) created from the data thus obtained and the response time difference ΔT.

図４から、最小二乗法により近似関数を作成するとよい相関があることがわかる。そして、温度ｘ（℃）、応答時間差ｙ（ｎｓｅｃ）とすると，yはｘの１次関数で近似することができる。すなわち、上記式（３）に示したように、１℃あたり０．２０８（ｎｓｅｃ）程度の補正をする必要があることがわかる。 It can be seen from FIG. 4 that there is a good correlation when an approximate function is created by the least square method. If the temperature is x (° C.) and the response time difference is y (nsec), y can be approximated by a linear function of x. That is, as shown in the above formula (3), it is necessary to correct about 0.208 (nsec) per 1 ° C.

（実施例２）
次に、上述の第２実施形態における補正の式（４）の算出方法について説明する。 (Example 2)
Next, the calculation method of the correction formula (4) in the second embodiment will be described.

まず、以下の装置構成を用いて、超音波の受信波形の温度依存特性について調査した。すなわち、図５に示したように、恒温槽７０と、恒温槽７０の内部に設けられた水槽７１と、水槽７１の底部に設けられた固定冶具７２と、オシロスコープ７３と、水槽７１内の水温計測に用いるＫ型熱電対７４に接続された温度計７５と、本発明に係る超音波流量計と、を備えた実験装置を用いて調査した。なお、本発明に係る超音波流量計は、第２実施形態の制御部３０（図２参照）と同様の制御部８０と、固定冶具７２の内側において対向するように且つ互いに超音波の送受信ができるように任意の距離を離して設けられた一対の超音波送受信部８１、８２（超音波プローブ）とを有している。 First, the temperature dependence characteristics of the received waveform of ultrasonic waves were investigated using the following apparatus configuration. That is, as shown in FIG. 5, the thermostat 70, the water tank 71 provided in the thermostat 70, the fixing jig 72 provided at the bottom of the water tank 71, the oscilloscope 73, and the water temperature in the water tank 71. An investigation was performed using an experimental apparatus including a thermometer 75 connected to a K-type thermocouple 74 used for measurement and the ultrasonic flowmeter according to the present invention. The ultrasonic flowmeter according to the present invention transmits and receives ultrasonic waves so as to face each other inside the fixed jig 72 and the control unit 80 similar to the control unit 30 (see FIG. 2) of the second embodiment. It has a pair of ultrasonic transmission / reception units 81 and 82 (ultrasonic probes) provided at an arbitrary distance so as to be able to.

超音波流量計における超音波受信部（振動子）の温度が１０℃の場合と４０℃の場合とにおける超音波の受信波形をオシロスコープ７３で実測すると、図６（ａ）（１０℃の場合）、図６（ｂ）（４０℃の場合）に示すような結果が得られた。すなわち、温度が高くなるほど、受信波形の波高値が低くなることがわかった。したがって、適正な温度補正を行えば、温度計などによる実測定ごとの別途温度検出を不要とすることができる。 When the ultrasonic wave reception waveform is measured with an oscilloscope 73 when the temperature of the ultrasonic wave receiver (vibrator) in the ultrasonic flowmeter is 10 ° C. and 40 ° C., FIG. The result as shown in FIG. 6B (in the case of 40 ° C.) was obtained. That is, it was found that the peak value of the received waveform decreases as the temperature increases. Therefore, if appropriate temperature correction is performed, it is not necessary to separately detect temperature for each actual measurement using a thermometer or the like.

次に、上記温度補正を行うための式を得るために、受信波の波高値と温度との相関関係を、図５に示した装置構成を用いて調査した。具体的には、恒温槽７０において、水槽７１内の水温を５℃〜５０℃に徐々に変化させるように制御することによって、超音波送受信部８１、８２の温度を経時的に変化させつつ５℃〜５０℃までの範囲で第２実施形態の動作と同様に超音波の送受信を行い、Ｋ型熱電対７４による水温のデータと、オシロスコープ７３から受信波形を取得し、制御部７０で計測した波高値とを検出して、超音波送受信部８１、８２の温度と受信波の波高値との相関関係を調査した。なお、水温と超音波送受信部８１、８２の温度とが十分に一致するようにしてから、調査を行った。 Next, in order to obtain an equation for performing the temperature correction, the correlation between the peak value of the received wave and the temperature was investigated using the apparatus configuration shown in FIG. Specifically, in the thermostatic chamber 70, the temperature of the ultrasonic transmission / reception units 81 and 82 is changed over time by controlling the water temperature in the water tank 71 to be gradually changed from 5 ° C. to 50 ° C. Ultrasonic waves were transmitted and received in the range from 50 ° C. to 50 ° C. in the same manner as the operation of the second embodiment, the water temperature data by the K-type thermocouple 74 and the received waveform from the oscilloscope 73 were acquired and measured by the control unit 70. The peak value was detected, and the correlation between the temperature of the ultrasonic transmission / reception units 81 and 82 and the peak value of the received wave was investigated. The investigation was conducted after the water temperature and the temperature of the ultrasonic transmission / reception units 81 and 82 were sufficiently matched.

上述のようにして得られた受信波の波高値と超音波送受信部８１、８２の温度との相関関係を図７に示す。この相関関係から補正の式（４）が得られた。受信波形の波高値から温度データを算出し、応答時間差の補正の式（３）に入力することで温度補正を行った。この結果、実測定ごとの別途温度検出を不要とすることができた。 FIG. 7 shows the correlation between the peak value of the received wave obtained as described above and the temperature of the ultrasonic transmission / reception units 81 and 82. From this correlation, the correction formula (4) was obtained. Temperature correction was performed by calculating temperature data from the peak value of the received waveform and inputting it into Equation (3) for correcting the response time difference. As a result, it was not necessary to separately detect the temperature for each actual measurement.

（実施例３）
上記第２実施形態と同様の装置構成で作製した超音波流量計について動作確認実験を行った。具体的には、配管内を６０ｍｍ／ｓの一定流速で流れる水について、水温を８℃〜６０℃まで経時的に変化させつつ、時間、温度及び流速の相関関係を調査した。その結果を図８に示す。 Example 3
An operation confirmation experiment was performed on an ultrasonic flowmeter manufactured with the same apparatus configuration as that of the second embodiment. Specifically, for water flowing at a constant flow rate of 60 mm / s in the pipe, the correlation between time, temperature and flow rate was investigated while changing the water temperature from 8 ° C. to 60 ° C. over time. The result is shown in FIG.

図８の結果から、流速の計測値については、補正前が２５ｍｍ／ｓ〜８８ｍｍ／ｓの範囲で経時的に変化したのに対し、補正後は５３ｍｍ／ｓ〜６７ｍｍ／ｓの範囲で安定して計測ができた。したがって、上記第２実施形態と同様の装置構成で作製した超音波流量計について、温度の変化が生じても、一定流速を安定して計測できることが確認できた。 From the result of FIG. 8, the measured value of the flow velocity changed over time in the range of 25 mm / s to 88 mm / s before the correction, but stabilized in the range of 53 mm / s to 67 mm / s after the correction. I was able to measure. Therefore, it was confirmed that a constant flow rate can be stably measured even when a temperature change occurs in the ultrasonic flowmeter manufactured with the same apparatus configuration as that of the second embodiment.

（実施例４）
実施例３と同様の超音波流量計により基準流量を設定し、実施例３と同様の超音波流量計と、従来の外付型の超音波流量計（計測可能な最小流速が３０ｍｍ／ｓ）との流量計測性能を比較した。 Example 4
The reference flow rate is set using the same ultrasonic flow meter as in Example 3, and the same ultrasonic flow meter as in Example 3 and a conventional external ultrasonic flow meter (minimum measurable flow velocity is 30 mm / s). The flow measurement performance was compared.

上記比較の結果を下記表１に示す。下記表１の結果から、実施例４と同様の超音波流量計においては、従来の超音波流量計では測定不可能な流速３０ｍｍ／ｓ以下の流量域において計測できるということが確認できた。 The results of the comparison are shown in Table 1 below. From the results shown in Table 1 below, it was confirmed that the ultrasonic flow meter similar to that of Example 4 can be measured in a flow rate range of 30 mm / s or less, which is impossible to measure with a conventional ultrasonic flow meter.

なお、本発明は上記実施形態及び実施例に限定されるものではなく、本発明の趣旨に基づいて種々の変形が可能であり、これらを本発明の範囲から排除するものではない。例えば、第１実施形態において、所定温度を高く設定したとしても冷却して所定温度に調整できるように、ヒーターの代わりに冷却装置を設けた超音波流量計としてもよい。 In addition, this invention is not limited to the said embodiment and Example, A various deformation | transformation is possible based on the meaning of this invention, and these are not excluded from the scope of the present invention. For example, in the first embodiment, an ultrasonic flow meter provided with a cooling device in place of the heater may be used so that it can be cooled and adjusted to the predetermined temperature even if the predetermined temperature is set high.

また、上記第１実施形態の超音波流量計においては、超音波送受信部を点対称配置としたが、第２実施形態に示したような並列配置としてもよい。逆に、第２実施形態の超音波流量計においては、超音波送受信部を並列配置としたが、第１実施形態に示したような点対称配置としてもよい。 Moreover, in the ultrasonic flowmeter of the said 1st Embodiment, although the ultrasonic transmission / reception part was made into point symmetry arrangement | positioning, it is good also as parallel arrangement | positioning as shown in 2nd Embodiment. Conversely, in the ultrasonic flowmeter of the second embodiment, the ultrasonic transmission / reception units are arranged in parallel, but may be arranged in a point-symmetric arrangement as shown in the first embodiment.

また、上記第１実施形態と第２実施形態とを組み合わせた超音波流量計としてもよい。すなわち、上記恒温槽を温度制御部等によって所定温度に調整して温度変化による測定誤差を発生させないようにすることができるとともに、超音波送受信部に温度変化が生じても補正処理して温度変化による測定誤差を発生させないようにすることができる超音波流量計としてもよい。 Moreover, it is good also as an ultrasonic flowmeter which combined the said 1st Embodiment and 2nd Embodiment. That is, the thermostat can be adjusted to a predetermined temperature by a temperature control unit or the like so as not to cause a measurement error due to a temperature change, and even if a temperature change occurs in the ultrasonic transmission / reception unit, a correction process is performed to change the temperature change. It is also possible to use an ultrasonic flow meter that can prevent the measurement error caused by.

また、上記第２実施形態においては、実際に超音波送受信部から検出した受信波形の情報について、予め超音波送受信部から取得し記憶部（図示せず）に記憶させておいた所定温度毎の受信波形の情報のうちいずれの情報に合致するか判定し、所定温度毎の受信波形の情報のうち合致した受信波形における温度を、配管（流路）内を流れる流体の温度として検出する温度検出部（図示せず）をＣＰＵ３７内に有していてもよい。なお、上記温度検出部による温度検出は、実測した際の超音波送受信部、配管、流体の温度がほぼ同様になった時点以降に行うことが好ましい。 In the second embodiment, information on the received waveform actually detected from the ultrasonic transmission / reception unit is acquired from the ultrasonic transmission / reception unit in advance and stored in a storage unit (not shown) for each predetermined temperature. Temperature detection that determines which of the received waveform information matches and detects the temperature in the received waveform that matches the received waveform information for each predetermined temperature as the temperature of the fluid flowing in the pipe (flow path) A unit (not shown) may be included in the CPU 37. In addition, it is preferable to perform the temperature detection by the said temperature detection part after the time when the temperature of the ultrasonic transmission / reception part at the time of actual measurement, piping, and the fluid became substantially the same.

上記第２実施形態及び変形例においては、ＣＰＵの内部に時間計測部、流量算出部、温度算出部などを設け作動させることができる構成としているが、これに限られず、時間計測部、流量算出部、温度検出部などを実行するプログラムをＣＰＵ外部の記憶装置内に設け、必要に応じてＣＰＵに読み込んで実行する構成としてもよい。 In the second embodiment and the modified example, a time measurement unit, a flow rate calculation unit, a temperature calculation unit, and the like can be provided and operated inside the CPU. However, the configuration is not limited thereto, and the time measurement unit and the flow rate calculation are not limited thereto. A program for executing the control unit, the temperature detection unit, and the like may be provided in a storage device outside the CPU, and read into the CPU and executed as necessary.

１測定経路
２、３、２３、２４、６１、６２、８１、８２、３０３、３０４、３１４、３１５超音波送受信部（振動子）
４、５、５０、７０恒温槽
６、７ヒーター
８、９温度検知部
１０温度制御部
１１、３２、６０、８０制御部
１２、３２ａ時間計測部
１３、３７流量算出部
２０、３００、３１０配管
２１、３０１、３１１、３１２超音波プローブ
２２、３０２、３１３、３１５プローブケース
５１、７１水槽
５２、７２固定冶具
５３、７３Ｋ型熱電対
５４、７５温度計
７３オシロスコープ
１００、２００超音波流量計
1 Measurement path 2, 3, 23, 24, 61, 62, 81, 82, 303, 304, 314, 315 Ultrasonic transceiver (vibrator)
4, 5, 50, 70 Constant temperature bath 6, 7 Heater 8, 9 Temperature detection unit 10 Temperature control unit 11, 32, 60, 80 Control unit 12, 32a Time measurement unit 13, 37 Flow rate calculation unit 20, 300, 310 Piping 21, 301, 311, 312 Ultrasonic probe 22, 302, 313, 315 Probe case 51, 71 Water tank 52, 72 Fixed jig 53, 73 K-type thermocouple 54, 75 Thermometer 73 Oscilloscope 100, 200 Ultrasonic flow meter

Claims

An ultrasonic flowmeter capable of measuring with a sampling time of the order of picoseconds,
It is possible to oscillate ultrasonic waves toward the upper or lower flow direction of the fluid in the flow path through which the fluid flows, and to receive ultrasonic waves coming from the upper or lower flow direction. A pair of possible ultrasonic transceivers;
A temperature adjustment unit for adjusting the temperature of the pair of ultrasonic transmission / reception units to a predetermined temperature;
A time measuring unit for measuring a time during which the ultrasonic wave propagates between the pair of ultrasonic transmitting / receiving units;
A flow rate calculation unit that calculates a flow rate based on a measurement result obtained by the time measurement unit;
A pair of thermostatic baths that are housed in a state where each of the pair of ultrasonic transmission / reception units is immersed in the liquid, with the liquid being sealed inside,
A pair of heaters housed in a state immersed in the liquid in each of the pair of thermostats ,
The temperature adjustment unit is
A pair of temperature detectors that are housed immersed in the liquid inside each of the pair of thermostats, and that can detect the temperature of each of the pair of ultrasonic transmission / reception units,
A temperature control unit that controls each output of the pair of heaters based on the temperature of each of the pair of ultrasonic transmission / reception units detected by the pair of temperature detection units. Ultrasonic flow meter.

An ultrasonic flowmeter capable of measuring with a sampling time of the order of picoseconds,
It is possible to oscillate ultrasonic waves toward the upper or lower flow direction of the fluid in the flow path through which the fluid flows, and to receive ultrasonic waves coming from the upper or lower flow direction. A pair of possible ultrasonic transceivers;
A time measuring unit for measuring a time during which the ultrasonic wave propagates between the pair of ultrasonic transmitting / receiving units;
Received waveform processing for correcting the received waveform received by each of the pair of ultrasonic transmitting / receiving units to the received waveform received by each of the pair of ultrasonic transmitting / receiving units having a predetermined temperature obtained in advance as necessary. And
A flow rate calculation unit that calculates a flow rate based on information obtained by the time measurement unit using information obtained by the reception waveform processing unit as necessary, and
In the reception waveform processing unit, information on the peak value of the reception waveform received by each of the pair of ultrasonic transmission / reception units and the reception waveform received by each of the pair of ultrasonic transmission / reception units having a predetermined temperature obtained in advance. Information on the crest value of the received waveform, information on the time obtained by the time measurement unit, and information on the temperature dependence characteristics of the crest value of the received waveform that the crest value of the received waveform of the ultrasonic wave becomes lower as the temperature increases. An ultrasonic flowmeter that performs the correction processing based on the above .

About the information of the received waveform detected from the ultrasonic transmission / reception unit, it is determined which information among the information of the reception waveform for each predetermined temperature previously acquired from the ultrasonic transmission / reception unit, and for each predetermined temperature The ultrasonic flowmeter according to claim 2, further comprising: a temperature detection unit that detects the temperature in the received waveform that matches the received waveform information as the temperature of the fluid flowing in the flow path.