JP4571898B2 - Current meter and flow meter - Google Patents

Current meter and flow meter Download PDF

Info

Publication number
JP4571898B2
JP4571898B2 JP2005289184A JP2005289184A JP4571898B2 JP 4571898 B2 JP4571898 B2 JP 4571898B2 JP 2005289184 A JP2005289184 A JP 2005289184A JP 2005289184 A JP2005289184 A JP 2005289184A JP 4571898 B2 JP4571898 B2 JP 4571898B2
Authority
JP
Japan
Prior art keywords
flow
phase difference
signal
drive signal
flow velocity
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.)
Expired - Fee Related
Application number
JP2005289184A
Other languages
Japanese (ja)
Other versions
JP2007101270A (en
Inventor
繁男 木村
隆弘 木綿
佳充 金岡
純也 谷川
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.)
Yazaki Corp
Original Assignee
Yazaki Corp
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 Yazaki Corp filed Critical Yazaki Corp
Priority to JP2005289184A priority Critical patent/JP4571898B2/en
Publication of JP2007101270A publication Critical patent/JP2007101270A/en
Application granted granted Critical
Publication of JP4571898B2 publication Critical patent/JP4571898B2/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Landscapes

  • Measuring Volume Flow (AREA)

Description

本発明は、ガス等の流体の流速乃至流量をその流路上において測定する流速計及び流量計に関するものである。   The present invention relates to a velocimeter and a flow meter that measure the flow velocity or flow rate of a fluid such as a gas on the flow path.

例えばガス等の流体の流量を流路上において測定する際に、既知の流路断面積に乗じて流量を求めるのに必要な、流路を流れる流体の速度を検出する技術として、流路上に配置したヒータを交流の駆動信号により通電駆動し、このヒータから流路における流体の流れ方向に間隔をおいて配置した温度センサが、ヒータから放出される熱の伝搬速度に応じて出力する交流の流速信号と、ヒータの通電駆動に用いる交流の駆動信号との位相差を求める方法が知られている(例えば特許文献1)。
特開平5−264567号公報
For example, when measuring the flow rate of a fluid such as gas on the flow path, it is placed on the flow path as a technique for detecting the velocity of the fluid flowing in the flow path, which is necessary to obtain the flow rate by multiplying the known cross-sectional area of the flow path. The heater is energized and driven by an AC drive signal, and the temperature sensor arranged at an interval in the flow direction of the fluid in the flow path from the heater outputs the AC flow velocity output in accordance with the propagation speed of the heat released from the heater A method for obtaining a phase difference between a signal and an AC driving signal used for energization driving of a heater is known (for example, Patent Document 1).
JP-A-5-264567

上記した、温度センサが出力する流速信号とヒータの通電駆動に用いる交流の駆動信号との位相差から流体の流速を求める方法は、流路を流れる流体の流速が変化すると、温度センサから出力される流速信号の位相が、流速に応じた量だけ変化することを利用して、流体の流速を求めるものであり、その精度は、駆動信号と流速信号との位相差を測定する際の時間に対する分解能によって定まる。   The above-described method for obtaining the flow velocity of the fluid from the phase difference between the flow velocity signal output from the temperature sensor and the AC drive signal used for energization driving of the heater is output from the temperature sensor when the flow velocity of the fluid flowing through the flow path changes. The flow rate of the fluid is calculated by changing the phase of the flow rate signal by an amount corresponding to the flow rate, and the accuracy is determined with respect to the time when the phase difference between the drive signal and the flow rate signal is measured. It depends on the resolution.

駆動信号と流速信号との位相差は、例えば、駆動信号と流速信号とをR,Sの各入力とするフリップフロップ回路を用いて、各信号のゼロクロス時点でR,Sの各入力が反転するタイミングの差から測定することができ、その際の測定分解能を司るファクタには、フリップフロップ回路のクロックの周期と、駆動信号や流速信号の周波数とがある。   The phase difference between the drive signal and the flow velocity signal is reversed, for example, by using a flip-flop circuit that uses the drive signal and the flow velocity signal as the R and S inputs, respectively, and the R and S inputs are inverted at the time of the zero crossing of each signal. The measurement can be performed from the difference in timing, and the factors governing the measurement resolution at that time include the cycle of the clock of the flip-flop circuit and the frequency of the drive signal and the flow velocity signal.

このうち、フリップフロップ回路のクロックの周期については、その周期を短くすればするほど、駆動信号と流速信号との位相差の測定分解能ひいては測定精度が高まるが、仮にフリップフロップ回路のクロック周期を短くすることができない事情がある場合には、駆動信号(ひいては流速信号)の周波数を低く(周期を長く)して、駆動信号や流速信号の一周期中に発生するフリップフロップ回路のクロック数を増やし、結果的に、クロック周期を短くするのと同様の状況にして、駆動信号と流速信号との位相差の測定分解能ひいては測定精度を高めようとすることになる。   Of these, the shorter the cycle of the clock of the flip-flop circuit, the higher the measurement resolution of the phase difference between the drive signal and the flow velocity signal and thus the measurement accuracy, but the clock cycle of the flip-flop circuit is temporarily shortened. If there is a situation that cannot be done, lower the frequency of the drive signal (and hence the flow rate signal) (and increase the cycle) to increase the number of clocks of the flip-flop circuit generated during one cycle of the drive signal or flow rate signal As a result, the measurement resolution of the phase difference between the drive signal and the flow velocity signal, and thus the measurement accuracy, are to be improved in the same situation as when the clock cycle is shortened.

しかしながら、例えば上述した駆動信号と流速信号のゼロクロス時点のタイミング差のように、駆動信号の特定の位相箇所の到来するタイミングと、流速信号の同じ位相箇所の到来するタイミングとの差を検出することで測定される両信号の位相差は、一周期に一度しか測定できないので、駆動信号の周波数を低くすると、駆動信号と流速信号との位相差の測定周期が長くなり、測定された位相差に基づいて求められる流路上の流体の流速の、流路を流れる流体の実流速の変化に対する追従性が低下してしまい、結果的に、流体の流速測定の精度を低下させてしまうことになる。   However, detecting the difference between the arrival timing of a specific phase location of the drive signal and the arrival timing of the same phase location of the flow velocity signal, such as the timing difference between the drive signal and the flow velocity signal described above, for example. Since the phase difference between the two signals measured in step 1 can only be measured once in one period, if the frequency of the drive signal is lowered, the measurement period of the phase difference between the drive signal and the flow rate signal becomes longer, resulting in a measured phase difference. The followability of the flow velocity of the fluid on the flow path obtained based on the change in the actual flow velocity of the fluid flowing through the flow path is lowered, and as a result, the accuracy of the flow velocity measurement of the fluid is lowered.

そして、上記した課題は、交流の駆動信号により通電駆動するのが、通電量によって放出する熱の量が変化するヒータである場合に限らず、例えば、ペルチェ素子のような、通電方向によって熱の放出と吸収とが切り換わり、かつ、通電量によって放出又は吸収する熱の量が変化するものを熱源として用いる場合にも、総じて当てはまるものである。   The above-described problem is not limited to the case where the energization drive is performed by the AC drive signal in a heater in which the amount of heat released changes depending on the energization amount. This also applies to the case where a heat source that switches between emission and absorption and whose amount of heat released or absorbed changes depending on the amount of energization is used as a heat source.

本発明は上記事情に鑑みなされたもので、本発明の目的は、流路における流体の流れ方向に間隔をおいて配置した熱源と温度センサを用い、上記した交流信号やこれを直線シフトした信号のような、一定の周期で電圧が変化する周期電圧波形の駆動信号により通電駆動された熱源から伝搬される熱を検出した温度センサが出力する流速信号の、駆動信号との位相差に基づいて、流路を流れる流体の流速乃至流量を測定する際に、駆動信号と流速信号との位相差の測定精度を高くしつつ、測定された位相差に基づいて求められる流路上の流体の流速乃至流量の、流路を流れる流体の実流速乃至流量の変化に対する追従性の低下を防ぎ、流体の流速乃至流量測定の精度を確保できる流速計及び流量計を提供することにある。   The present invention has been made in view of the above circumstances, and an object of the present invention is to use the heat source and the temperature sensor arranged at intervals in the flow direction of the fluid in the flow path, and use the AC signal described above or a signal obtained by linearly shifting the AC signal. Based on the phase difference from the drive signal of the flow velocity signal output by the temperature sensor that detects the heat propagated from the heat source that is energized and driven by the drive signal of the periodic voltage waveform whose voltage changes at a constant cycle, such as When measuring the flow velocity or flow rate of the fluid flowing through the flow path, the flow velocity of the fluid on the flow path obtained based on the measured phase difference while increasing the measurement accuracy of the phase difference between the drive signal and the flow velocity signal An object of the present invention is to provide a flowmeter and a flowmeter that can prevent deterioration in followability of the flow rate with respect to changes in the actual flow rate or flow rate of the fluid flowing through the flow path, and can ensure the accuracy of the flow rate or flow rate measurement of the fluid.

上記目的を達成する請求項1及び請求項2記載の本発明は流速計に関するものであり、請求項3記載の本発明は流量計に関するものである。   The present invention according to claim 1 and claim 2 that achieves the above object relates to a flow meter, and the present invention according to claim 3 relates to a flow meter.

そして、請求項1に記載した本発明の流速計は、一定の周期で電圧が変化する周期電圧波形の駆動信号により通電駆動される熱源と、該熱源が放出又は吸収する熱を検出しその温度に応じた流速信号を出力する温度センサとを有するフローセンサを、被測定対象の流体の流路上に、前記熱源と前記温度センサとが前記流路における流体の流れ方向に間隔をおくように配置し、前記流速信号と前記駆動信号との位相差を検出した位相差信号出力手段が該位相差に応じて出力する位相差信号に基づいて、前記流路を流れる流体の流速を測定する流速計において、前記流路の前記流体の流れる条件が等しいn箇所(n=2以上の整数)に各々配置される前記フローセンサと、前記各フローセンサを相互に熱的に絶縁する熱絶縁手段と、前記各フローセンサの前記熱源を、1/n周期ずつ互いに位相をずらした前記駆動信号により各々通電駆動する駆動手段とを備えており、前記駆動信号の1/n周期おきに順次前記位相差信号出力手段により検出される前記各フローセンサ毎の前記流速信号と前記駆動信号との位相差に応じた前記位相差信号に基づいて、前記流路を流れる流体の流速を、前記駆動信号の1/n周期おきに測定することを特徴とする。   The current meter according to the first aspect of the present invention detects a heat source that is energized and driven by a drive signal having a periodic voltage waveform whose voltage changes at a constant period, and heat that is released or absorbed by the heat source. A flow sensor having a temperature sensor that outputs a flow velocity signal corresponding to the flow rate is arranged on the flow path of the fluid to be measured so that the heat source and the temperature sensor are spaced apart from each other in the flow direction of the fluid in the flow path. A flowmeter that measures the flow velocity of the fluid flowing through the flow path based on the phase difference signal output by the phase difference signal output means that detects the phase difference between the flow velocity signal and the drive signal according to the phase difference. In the flow path, the flow sensor disposed at each of the n locations where the fluid flow conditions are equal (integer of n = 2 or more), and thermal insulation means for thermally insulating the flow sensors from each other, Each flow Drive means for energizing and driving the heat source of the sensor by the drive signals that are shifted in phase by 1 / n period, and sequentially by the phase difference signal output means every 1 / n period of the drive signal. Based on the phase difference signal corresponding to the phase difference between the flow velocity signal and the drive signal for each detected flow sensor, the flow velocity of the fluid flowing through the flow path is determined every 1 / n period of the drive signal. It is characterized by measuring.

また、請求項2に記載した本発明の流速計は、請求項1に記載した本発明の流速計において、前記各フローセンサが、前記熱源及び前記温度センサが配置される絶縁層膜と、該絶縁膜層の前記熱源及び前記温度センサが配置されたダイヤフラム領域の周縁領域に設けられたシリコン基台とを有しており、前記各フローセンサの前記シリコン基台どうしを連結することでn個の前記フローセンサが一体に形成されており、前記熱絶縁手段が、前記各フローセンサの前記シリコン基台によって構成されているものとした。   Moreover, the flowmeter of the present invention described in claim 2 is the flowmeter of the present invention described in claim 1, wherein each flow sensor includes an insulating layer film in which the heat source and the temperature sensor are disposed, The heat source of the insulating film layer and a silicon base provided in the peripheral area of the diaphragm area where the temperature sensor is arranged, and n pieces are obtained by connecting the silicon bases of the respective flow sensors. The flow sensor is integrally formed, and the thermal insulation means is constituted by the silicon base of each flow sensor.

さらに、請求項3に記載した本発明の流量計は、一定の周期で電圧が変化する周期電圧波形の駆動信号により通電駆動される熱源と、該熱源が放出又は吸収する熱を検出しその温度に応じた流速信号を出力する温度センサとを有するフローセンサを、被測定対象の流体の流路上に、前記熱源と前記温度センサとが前記流路における流体の流れ方向に間隔をおくように配置し、前記流速信号と前記駆動信号との位相差を検出した位相差信号出力手段が該位相差に応じて出力する位相差信号に基づいて、前記流路を流れる流体の流量を測定する流量計であって、請求項1又は2記載の流速計を備え、前記流速計により測定された前記流路を流れる流体の流速、及び、前記流路の既知の断面積を用いて、前記流路を流れる流体の流量を測定することを特徴とする。   Furthermore, the flow meter of the present invention described in claim 3 detects a heat source that is energized and driven by a drive signal having a periodic voltage waveform whose voltage changes at a constant period, and detects the heat released or absorbed by the heat source. A flow sensor having a temperature sensor that outputs a flow velocity signal corresponding to the flow rate is arranged on the flow path of the fluid to be measured so that the heat source and the temperature sensor are spaced apart from each other in the flow direction of the fluid in the flow path. And a flowmeter for measuring the flow rate of the fluid flowing through the flow path based on the phase difference signal output in accordance with the phase difference by the phase difference signal output means that detects the phase difference between the flow velocity signal and the drive signal. The flow rate is measured using the flow velocity of the fluid flowing through the flow path measured by the flow velocity meter and the known cross-sectional area of the flow path. Measure the flow rate of flowing fluid And features.

請求項1に記載した本発明の流速計によれば、駆動手段が周期電圧波形の信号の駆動信号により各フローセンサの熱源を通電駆動させると、熱源の通電量乃至放出(又は吸収)熱量が連続的に増減され、これに追従して各フローセンサの温度センサが出力する流速信号のレベルが増減するので、流速信号は、駆動信号と同じ周波数の信号成分、又は、駆動信号の周波数の倍の周波数成分を含む周期電圧波形となる。   According to the velocimeter of the present invention as set forth in claim 1, when the driving means drives the heat source of each flow sensor by the drive signal of the signal of the periodic voltage waveform, the energization amount or the emission (or absorption) heat amount of the heat source is increased. The flow rate signal is increased or decreased continuously, and the level of the flow rate signal output from the temperature sensor of each flow sensor increases or decreases accordingly. Therefore, the flow rate signal is a signal component having the same frequency as the drive signal or twice the frequency of the drive signal. It becomes a periodic voltage waveform including the frequency component.

ところで、各フローセンサの温度センサが出力する周期電圧波形の流速信号に含まれる、駆動信号と同じ周波数の信号成分、又は、駆動信号の周波数の倍の周波数成分は、駆動手段が各フローセンサの熱源の通電駆動に用いる駆動信号との位相差が、流路を流れる流体の流速に応じて変化するので、各フローセンサの温度センサが出力する周期電圧波形の流速信号の、各フローセンサの駆動手段が熱源の通電駆動に用いる駆動信号との位相差の変動を監視すれば、流路を流れる流体の流速が測定されることになる。   By the way, the signal component of the same frequency as the drive signal or the frequency component of the frequency of the drive signal included in the flow velocity signal of the periodic voltage waveform output from the temperature sensor of each flow sensor is determined by the drive means of each flow sensor. Since the phase difference from the drive signal used for energization drive of the heat source changes according to the flow velocity of the fluid flowing through the flow path, the flow rate signal of the periodic voltage waveform output from the temperature sensor of each flow sensor is driven by each flow sensor. If the means monitors the fluctuation of the phase difference from the drive signal used for energization driving of the heat source, the flow velocity of the fluid flowing through the flow path is measured.

そして、駆動手段がn個のフローセンサの熱源を、1/n周期ずつ互いに位相をずらした駆動信号により各々通電駆動することから、位相差信号出力手段が駆動信号の特定の位相箇所の到来するタイミングと流速信号の同じ位相箇所の到来するタイミングとの差を検出して位相差信号を出力するタイミングが、各フローセンサ毎に1/n周期ずつずれて到来することになる。   Then, the drive means drives the heat sources of the n flow sensors by drive signals that are out of phase with each other by 1 / n period, so that the phase difference signal output means arrives at a specific phase portion of the drive signal. The timing for detecting the difference between the timing and the timing at which the same phase portion of the flow velocity signal arrives and outputting the phase difference signal arrives with a shift of 1 / n period for each flow sensor.

しかも、各フローセンサの相互間が熱絶縁手段により互いに熱的に絶縁されていることから、n個のフローセンサの熱源を駆動手段により同時に通電駆動しても、それぞれの熱源が放出又は吸収する熱によって他のフローセンサの温度センサの出力に影響が及ぼされることはない。   In addition, since the flow sensors are thermally insulated from each other by the thermal insulation means, even if the heat sources of the n flow sensors are energized and driven simultaneously by the drive means, the respective heat sources are released or absorbed. The output of the temperature sensor of the other flow sensor is not affected by heat.

そのため、駆動信号の1/n周期毎に位相差検出手段が出力する、各フローセンサの熱源の駆動信号と温度センサの流速信号との位相差に応じた位相差信号が、駆動信号の1/n周期ずつ異なるタイミングにおける流路を流れる流体の流速に応じたものとなることから、駆動信号と流速信号との位相差を測定するタイミングが駆動信号の一周期に一度しか到来しなくても、流路に配置したフローセンサの個数分、駆動信号の一周期を分割した細かいタイミング毎に、流路を流れる流体の流速が測定されることになる。   Therefore, the phase difference signal corresponding to the phase difference between the drive signal of the heat source of each flow sensor and the flow rate signal of the temperature sensor, which is output by the phase difference detection means every 1 / n cycle of the drive signal, is 1 / n of the drive signal. Since it corresponds to the flow velocity of the fluid flowing through the flow path at different timings by n cycles, even if the timing for measuring the phase difference between the drive signal and the flow velocity signal comes only once in one cycle of the drive signal, The flow velocity of the fluid flowing in the flow path is measured at every fine timing obtained by dividing one cycle of the drive signal by the number of flow sensors arranged in the flow path.

よって、駆動信号と流速信号との位相差の測定分解能を高めるために、位相差測定に用いるクロックの周期を短くすることができない場合、それに代えて駆動信号の周波数を低くすることで、駆動信号の低周波数化に伴いフローセンサにおける駆動信号と流速信号との位相差を測定するタイミングの到来する周期が長くなってしまっても、流路を流れる流体の流速の測定周期が長くなってしまうのを防ぎ、測定された位相差に基づいて求められる流路上の流体の流速の、流路を流れる流体の実流速の変化に対する追従性の低下を防ぎ、流体の流速測定の精度を確保することができる。   Therefore, in order to increase the measurement resolution of the phase difference between the drive signal and the flow velocity signal, if the clock cycle used for phase difference measurement cannot be shortened, the drive signal can be reduced by lowering the frequency of the drive signal instead. As the frequency of the flow sensor is lowered, the measurement period of the flow velocity of the fluid flowing in the flow path becomes longer even if the timing of measuring the phase difference between the drive signal and the flow velocity signal in the flow sensor becomes longer. To prevent the fluid flow velocity on the flow path obtained based on the measured phase difference from deteriorating following the change in the actual flow velocity of the fluid flowing through the flow path, and to ensure the accuracy of fluid flow velocity measurement. it can.

また、請求項2に記載した本発明の流速計によれば、請求項1に記載した本発明の流速計において、n個のフローセンサを一体化することで各フローセンサを流路の流体の流れる条件が等しい箇所に容易に配置することができる。   Further, according to the flowmeter of the present invention described in claim 2, in the flowmeter of the present invention described in claim 1, each flow sensor is integrated with the flow sensor by integrating n flow sensors. It can be easily arranged at a location where the flowing conditions are equal.

そして、請求項3に記載した本発明の流量計によれば、請求項1又は2に記載した本発明の流速計によって高精度で測定された、流路を流れる流体の流速を用いて、流路を流れる流体の流量を高精度で計測することができる。   According to the flowmeter of the present invention described in claim 3, the flow rate of the fluid flowing through the flow path, which is measured with high accuracy by the flowmeter of the present invention described in claim 1 or 2, is used. The flow rate of the fluid flowing through the passage can be measured with high accuracy.

以下、本発明による流量計の実施形態を、流速計の実施形態と共に、図面を参照して説明する。   Hereinafter, an embodiment of a flow meter according to the present invention will be described together with an embodiment of a current meter with reference to the drawings.

まず、本発明による流速計を適用した本発明の第1実施形態に係るガス流量計と、後に説明する本発明の第3実施形態に係るガス流量計とにおいて使用されるフローセンサの概略構成について、図1及び図2を参照して説明する。   First, a schematic configuration of a flow sensor used in a gas flow meter according to a first embodiment of the present invention to which a current meter according to the present invention is applied and a gas flow meter according to a third embodiment of the present invention to be described later. A description will be given with reference to FIGS.

図1の説明図中引用符号3で示すフローセンサは、例えば特開平9−257821号公報において図1を参照して説明されているような、図2の断面図に示されているように、絶縁被膜32を上面に積層したSi基板31(請求項中のシリコン基台に相当)の中央部を違法性エッチングにより除去することで、絶縁性膜32の中央部にダイヤフラム領域32aを形成し、このダイヤフラム領域32a上に、図1に示されているように、マイクロマシニング加工によって、マイクロヒータ33(請求項中の熱源に相当)及びサーモパイル35(請求項中の温度センサに相当)を形成して構成されたものであり、ガス(請求項中の被測定対象の流体に相当)の流路S上に、マイクロヒータ33が流体の流れ方向における上流側に、サーモパイル35が下流側に位置するように配置されている。   The flow sensor indicated by reference numeral 3 in the explanatory diagram of FIG. 1 is shown in a sectional view of FIG. 2 as described with reference to FIG. 1 in, for example, Japanese Patent Laid-Open No. 9-257821. By removing the central portion of the Si substrate 31 (corresponding to the silicon base in the claims) having the insulating film 32 laminated on the upper surface by illegal etching, a diaphragm region 32a is formed in the central portion of the insulating film 32, On the diaphragm region 32a, as shown in FIG. 1, a micro heater 33 (corresponding to a heat source in claims) and a thermopile 35 (corresponding to a temperature sensor in claims) are formed by micromachining. The microheater 33 is disposed on the upstream side in the fluid flow direction on the flow path S of the gas (corresponding to the fluid to be measured in the claims). There are disposed so as to be positioned downstream.

このフローセンサ3では、マイクロヒータ33を駆動信号により通電駆動することでマイクロヒータ33が熱を放出し、マイクロヒータ33から伝達された熱の温度に応じた起電力がサーモパイル35に発生し、この起電力がサーモパイル35から、流路Sを流れるガスの流量に応じた流速信号として出力されるように構成されている。   In this flow sensor 3, the microheater 33 emits heat by energizing and driving the microheater 33 with a drive signal, and an electromotive force corresponding to the temperature of the heat transmitted from the microheater 33 is generated in the thermopile 35. The electromotive force is configured to be output from the thermopile 35 as a flow velocity signal corresponding to the flow rate of the gas flowing through the flow path S.

また、このフローセンサ3は、ダイヤフラム領域32aの熱容量がそれ以外の絶縁被膜32部分の熱容量に比べて非常に小さくなっていて、これにより、マイクロヒータ33が発する熱が流路Sを流れるガス以外の媒体を介してサーモパイル35に伝達されないようになっており、その一方で、ダイヤフラム領域32aを除く絶縁被膜32部分がダイヤフラム領域32aに比べて遙かに熱を伝達しやすいSi基板31によって、周囲の環境と同程度の温度となるように構成されていることから、ダイヤフラム領域32a内の熱分布は周囲から熱的に絶縁されるようになっている。   Further, in the flow sensor 3, the heat capacity of the diaphragm region 32a is very small as compared with the heat capacity of the other insulating coating 32, so that the heat generated by the microheater 33 is other than the gas flowing through the flow path S. On the other hand, the insulating coating 32 excluding the diaphragm region 32a is not easily transmitted to the thermopile 35 through the medium of the medium, and the surrounding area is provided by the Si substrate 31 that is much easier to transfer heat than the diaphragm region 32a. Therefore, the heat distribution in the diaphragm region 32a is thermally insulated from the surroundings.

次に、上述したフローセンサ3を用いて流路Sを流れるガスの流量を測定する、本発明の第1実施形態に係るガス流量計の概略構成について、図3のブロック図を参照して説明する。   Next, a schematic configuration of the gas flowmeter according to the first embodiment of the present invention that measures the flow rate of the gas flowing through the flow path S using the flow sensor 3 described above will be described with reference to the block diagram of FIG. To do.

図3中引用符号1で示す第1実施形態のガス流量計は、前記フローセンサ3と、前記マイクロヒータ33を正弦波状の駆動信号により通電駆動させる駆動回路5(請求項中の駆動手段に相当)と、前記サーモパイル35から出力される流速信号を増幅するアンプ7と、アンプ7によって増幅された流速信号から駆動回路5の駆動信号と同じ周波数成分のみを通過させるバンドパスフィルタ9と、駆動回路5の駆動信号の位相に対するバンドパスフィルタ9を通過した流速信号の位相の差を検出し位相差検出信号(請求項中の位相差信号に相当)を出力する位相差検出回路11(請求項中の位相差信号出力手段に相当)とを有する流速測定ユニットAを3つ備えている。   The gas flow meter of the first embodiment indicated by reference numeral 1 in FIG. 3 is a drive circuit 5 (corresponding to drive means in claims) for energizing and driving the flow sensor 3 and the microheater 33 with a sinusoidal drive signal. ), An amplifier 7 that amplifies the flow velocity signal output from the thermopile 35, a bandpass filter 9 that passes only the same frequency component as the drive signal of the drive circuit 5 from the flow velocity signal amplified by the amplifier 7, and a drive circuit A phase difference detection circuit 11 for detecting a phase difference of the flow velocity signal that has passed through the band pass filter 9 with respect to the phase of the drive signal 5 and outputting a phase difference detection signal (corresponding to the phase difference signal in the claims). Three flow velocity measuring units A having a phase difference signal output means).

また、第1実施形態のガス流量計1は、各流速測定ユニットAの位相差検出回路11からの位相差検出信号から流路Sを流れるガスの流速乃至流量を演算するマイクロコンピュータ等の演算装置13を備えている。   Further, the gas flow meter 1 of the first embodiment is an arithmetic device such as a microcomputer that calculates the flow velocity or flow rate of the gas flowing through the flow path S from the phase difference detection signal from the phase difference detection circuit 11 of each flow velocity measurement unit A. 13 is provided.

尚、前記各流速測定ユニットAのフローセンサ3は、流路Sにおけるガスの流れる条件が等しい箇所に各々離して配置されており、互いのマイクロヒータ33が発する熱が他のフローセンサ3のサーモパイル35によって感知されることのないように、各フローセンサ3どうしが、それぞれのSi基板31と互いの間隔とによって熱的に絶縁されている。   The flow sensors 3 of the respective flow velocity measuring units A are arranged apart from each other at the same flow conditions of the gas in the flow path S, and the heat generated by each microheater 33 is the thermopile of the other flow sensor 3. The flow sensors 3 are thermally insulated from each other by the respective Si substrates 31 so as not to be sensed by 35.

また、前記各流速測定ユニットAの駆動回路5は、図4に回路図で示すように、水晶発振器51の発振周波数に応じた正弦波の信号を、その振幅の全幅に亘って正電位又は負電位となるように、後段のアンプ53により直流シフトさせて、この正電位又は負電位の正弦波による信号を、前記駆動信号として前記フローセンサ3のマイクロヒータ33に出力するように構成されており、かつ、流速測定ユニットAの個数分の1である1/3ずつ互いの位相をずらして駆動信号を出力するように構成されている。   Further, as shown in the circuit diagram of FIG. 4, the driving circuit 5 of each flow velocity measuring unit A outputs a sine wave signal corresponding to the oscillation frequency of the crystal oscillator 51 over the entire width of its amplitude. The signal is shifted by a direct-current amplifier 53 so that it becomes a potential, and a signal based on a positive or negative sine wave is output to the micro heater 33 of the flow sensor 3 as the drive signal. In addition, the drive signals are output with the phases shifted by 1/3, which is one-third of the number of the flow velocity measuring units A.

さらに、前記各流速測定ユニットAの位相差検出回路11は、図5に回路図で示すように、駆動回路5の駆動信号をコンデンサC1でカップリングし、電源Vcc(本実施形態ではDC5V)とプルアップ抵抗R1により、抵抗R2とプルアップ抵抗R1との分圧比により定まる電位にプルアップした後、抵抗R3,R4の中点に生成される駆動信号の振幅の中間電位(本実施形態では2.5V)のDC電圧とコンパレータA1で比較し、コンパレータA1の比較出力をRSフリップフロップF/Fの入力Sに入力すると共に、バンドパスフィルタ9を通過した流速信号をコンデンサC2でカップリングし、電源Vccとプルアップ抵抗R5により、抵抗R6とプルアップ抵抗R5との分圧比により定まる電位にプルアップした後、抵抗R3,R4の中点に生成される駆動信号の振幅の中間電位のDC電圧とコンパレータA2で比較し、コンパレータA2の比較出力をRSフリップフロップF/Fの入力Rに入力して、駆動回路5の駆動信号の位相に対してバンドパスフィルタ9を通過した流速信号の位相がずれている期間、Hレベルの位相差検出信号をRSフリップフロップF/Fから出力するように構成されている。   Further, as shown in the circuit diagram of FIG. 5, the phase difference detection circuit 11 of each flow velocity measuring unit A couples the drive signal of the drive circuit 5 with a capacitor C1, and supplies power Vcc (DC5V in this embodiment). After the pull-up resistor R1 pulls up to a potential determined by the voltage dividing ratio between the resistor R2 and the pull-up resistor R1, the intermediate potential of the amplitude of the drive signal generated at the midpoint of the resistors R3 and R4 (in this embodiment, 2). .5V) is compared with the DC voltage of the comparator A1, the comparison output of the comparator A1 is input to the input S of the RS flip-flop F / F, and the flow rate signal that has passed through the bandpass filter 9 is coupled by the capacitor C2. After pulling up to a potential determined by the voltage dividing ratio of the resistor R6 and the pull-up resistor R5 by the power source Vcc and the pull-up resistor R5, the resistor R3 The comparator A2 compares the DC voltage of the intermediate potential of the drive signal generated at the midpoint of R4 with the comparator A2, inputs the comparison output of the comparator A2 to the input R of the RS flip-flop F / F, and drives the drive circuit 5 The phase difference detection signal of H level is output from the RS flip-flop F / F during a period in which the phase of the flow velocity signal that has passed through the bandpass filter 9 is shifted with respect to the phase of the signal.

尚、本実施形態では、抵抗R1,R2,R3,R4,R5,R6に全て同じ抵抗値のものが使用されている。   In the present embodiment, the resistors R1, R2, R3, R4, R5, and R6 have the same resistance value.

さらに、前記演算装置13は、各流速測定ユニットAの位相差検出回路11から各々出力された位相差検出信号を、流路Sを流れるガスの流速に換算するための換算式に関するデータや、換算したガスの流速から流路Sを流れるガスの流量を演算するために必要な、流路Sの断面積のデータ等を、内部のメモリに記憶している。   Further, the arithmetic device 13 is configured to convert the phase difference detection signal output from the phase difference detection circuit 11 of each flow velocity measurement unit A into data relating to a conversion formula for converting the phase difference detection signal into the flow velocity of the gas flowing through the flow path S, The data of the cross-sectional area of the flow path S and the like necessary for calculating the flow rate of the gas flowing through the flow path S from the flow velocity of the gas is stored in the internal memory.

以上の構成による第1実施形態のガス流量計1では、各流速測定ユニットAの駆動回路5がマイクロヒータ33を通電駆動させるのに用いる、正弦波を直流シフトさせた正電位又は負電位の駆動信号は、極性が正負の相互間で反転せず単にその電位が正弦波状に変化するだけであり、マイクロヒータ33の通電量も正弦波状に増減されるので、各流速測定ユニットAのマイクロヒータ33から放出される熱を検出したサーモパイル35が出力する流速信号の波形は、駆動信号と同じ周波数の波形となる。   In the gas flow meter 1 of the first embodiment having the above-described configuration, the drive circuit 5 of each flow velocity measurement unit A is used to drive the microheater 33 by energization. The signal does not invert between the positive and negative polarities, and the potential merely changes in a sine wave form. The energization amount of the micro heater 33 is also increased or decreased in a sine wave form. The waveform of the flow velocity signal output from the thermopile 35 that has detected the heat released from is a waveform having the same frequency as the drive signal.

駆動信号と同じ周波数の波形であるとはいえ、サーモパイル35が出力する流速信号には、駆動信号と同じ基本周波数成分に加えて他の周波数成分が重畳されているのに対し、流速の変化に対する流速信号の位相差の変化は流速信号の周波数に依存して定まるため、基本周波数以外の周波数成分を含んでいるサーモパイル35からの流速信号をそのままの波形で使用したのでは、位相差検出回路11における駆動信号との位相差検出を正確に行うことができない。   Although the waveform has the same frequency as that of the drive signal, the flow velocity signal output from the thermopile 35 is superimposed with other frequency components in addition to the same basic frequency component as that of the drive signal. Since the change in the phase difference of the flow velocity signal is determined depending on the frequency of the flow velocity signal, if the flow velocity signal from the thermopile 35 containing frequency components other than the fundamental frequency is used as it is, the phase difference detection circuit 11 In this case, it is impossible to accurately detect the phase difference from the drive signal.

しかし、この流速信号に含まれる基本周波数以外の周波数成分はバンドパスフィルタ9において除去されるので、位相差検出回路11に入力されるのは、駆動信号の基本周波数による正弦波となる。   However, since the frequency components other than the fundamental frequency included in the flow velocity signal are removed by the bandpass filter 9, what is input to the phase difference detection circuit 11 is a sine wave based on the fundamental frequency of the drive signal.

そして、各流速測定ユニットAのサーモパイル35が出力する流速信号の波形は、流路Sを流れるガスの流速が速ければ速いほど、位相が進んで駆動信号に対する位相の遅れが縮小し、かつ、振幅が増加するように変形するので、駆動回路5の駆動信号の位相に対するバンドパスフィルタ9を通過した流速信号の位相の差に応じたHレベルの期間を有する、各流速測定ユニットAの位相差検出回路11からの位相差検出信号のディーティー比は、流路Sを流れるガスの流速を反映した値となる。   The waveform of the flow velocity signal output from the thermopile 35 of each flow velocity measuring unit A is such that the higher the flow velocity of the gas flowing through the flow path S, the more the phase is advanced and the phase delay with respect to the drive signal is reduced. The phase difference detection of each flow velocity measuring unit A has an H level period corresponding to the phase difference of the flow velocity signal that has passed through the band-pass filter 9 with respect to the phase of the drive signal of the drive circuit 5. The duty ratio of the phase difference detection signal from the circuit 11 is a value reflecting the flow velocity of the gas flowing through the flow path S.

さらに、3つの流速測定ユニットAの駆動回路5からマイクロヒータ33に各々出力される駆動信号の位相が1/3ずつ互いにずれていることから、各流速測定ユニットAの位相差検出回路11のRSフリップフロップF/FからHレベルの位相差検出信号が出力される期間も、駆動信号の一周期の1/3ずつずれることになる。   Further, since the phases of the drive signals output from the drive circuits 5 of the three flow velocity measuring units A to the micro heater 33 are shifted from each other by 1/3, the RS of the phase difference detection circuit 11 of each flow velocity measurement unit A The period during which the H-level phase difference detection signal is output from the flip-flop F / F is also shifted by 1/3 of one cycle of the drive signal.

このため、各流速測定ユニットAの位相差検出回路11から駆動信号の一周期の1/3ずつずれて出力される位相差検出信号を取り込んだ演算装置13において、内部のメモリに記憶されたデータに基づいて、流路Sを流れるガスの流速乃至流量が、駆動信号の一周期の1/3の周期毎に測定されることになる。   For this reason, the data stored in the internal memory in the arithmetic unit 13 that has fetched the phase difference detection signal output from the phase difference detection circuit 11 of each flow velocity measurement unit A with a shift of 1/3 of one cycle of the drive signal. Based on the above, the flow rate or flow rate of the gas flowing through the flow path S is measured every 1/3 period of one period of the drive signal.

よって、流速測定の分解能を高めるためにRSフリップフロップF/Fのクロック周期を短くすることができず、その代わりに駆動回路5が出力する駆動信号の周波数を低く(周期を長く)することになっても、駆動信号の一周期の1/3の短い周期でガスの流速乃至流量の測定が行えるようにして、測定された位相差に基づいて求められる流路S上のガスの流速の、流路Sを流れるガスの実流速の変化に対する追従性の低下を防ぎ、ガスの流量測定の精度を確保することができる。   Therefore, the clock cycle of the RS flip-flop F / F cannot be shortened in order to increase the resolution of the flow velocity measurement. Instead, the frequency of the drive signal output from the drive circuit 5 is lowered (the cycle is increased). Even so, the flow rate or flow rate of the gas can be measured in a cycle that is 1/3 of one cycle of the drive signal, and the flow rate of the gas on the flow path S obtained based on the measured phase difference is It is possible to prevent a decrease in followability with respect to a change in the actual flow velocity of the gas flowing through the flow path S and to ensure the accuracy of the gas flow rate measurement.

次に、本発明による流速計を適用した本発明の第2実施形態に係るガス流量計と、後に説明する本発明の第4実施形態に係るガス流量計とにおいて使用されるフローセンサの概略構成について、図6の説明図を参照して説明する。   Next, a schematic configuration of a flow sensor used in the gas flow meter according to the second embodiment of the present invention to which the current meter according to the present invention is applied and the gas flow meter according to the fourth embodiment of the present invention to be described later. Will be described with reference to the explanatory diagram of FIG.

図6中引用符号3Aで示すフローセンサは、図1及び図2を参照して説明したフローセンサ3のマイクロヒータ33に代えて、ペルチェ素子37を用いて構成されたものであり、ガスの流路S上に、ペルチェ素子37が流体の流れ方向における上流側に、サーモパイル35が下流側に位置するように配置されている。   The flow sensor denoted by reference numeral 3A in FIG. 6 is configured by using a Peltier element 37 instead of the micro heater 33 of the flow sensor 3 described with reference to FIGS. On the path S, the Peltier element 37 is disposed on the upstream side in the fluid flow direction, and the thermopile 35 is positioned on the downstream side.

このフローセンサ3Aでは、ペルチェ素子37を駆動信号により通電駆動することで、電流の流れる方向に応じてペルチェ素子37が熱を放出又は吸収し、ペルチェ素子37から伝達された熱の温度に応じた起電力がサーモパイル35に発生し、この起電力がサーモパイル35から、流路Sを流れるガスの流量に応じた流速信号として出力されるように構成されている。   In this flow sensor 3A, the Peltier element 37 is energized and driven by a drive signal, whereby the Peltier element 37 releases or absorbs heat according to the direction of current flow, and according to the temperature of the heat transmitted from the Peltier element 37. An electromotive force is generated in the thermopile 35, and the electromotive force is output from the thermopile 35 as a flow velocity signal corresponding to the flow rate of the gas flowing through the flow path S.

また、ペルチェ素子37が放出又は吸収する熱が流路Sを流れるガス以外の媒体を介してサーモパイル35に伝達されないように、ダイヤフラム領域32aがこれを除く絶縁被膜32部分に対してSi基板31によって熱的に絶縁されている点は、図1及び図2を参照して説明したフローセンサ3と同様である。   In addition, the diaphragm region 32a is formed by the Si substrate 31 with respect to the insulating coating 32 except for the heat that the Peltier element 37 emits or absorbs to the thermopile 35 through a medium other than the gas flowing in the flow path S. It is the same as the flow sensor 3 described with reference to FIGS. 1 and 2 in that it is thermally insulated.

次に、上述したフローセンサ3Aを用いて流路Sを流れるガスの流量を測定する、本発明の第2実施形態に係るガス流量計の概略構成について、図7のブロック図を参照して説明する。   Next, a schematic configuration of the gas flowmeter according to the second embodiment of the present invention that measures the flow rate of the gas flowing through the flow path S using the flow sensor 3A described above will be described with reference to the block diagram of FIG. To do.

図7中引用符号1Aで示す第2実施形態のガス流量計は、各流速測定ユニットAのフローセンサ3をフローセンサ3Aに替えた他、駆動回路5から直流シフト用のアンプ53を省略して正電位と負電位とに跨った電位の正弦波による交流信号を、前記駆動信号として前記フローセンサ3Aのペルチェ素子37に出力する駆動回路5Aを用いた点の他は、第1実施形態のガス流量計1と同様に構成されている。   In the gas flow meter of the second embodiment indicated by reference numeral 1A in FIG. 7, the flow sensor 3 of each flow velocity measuring unit A is replaced with the flow sensor 3A, and the DC shift amplifier 53 is omitted from the drive circuit 5. The gas according to the first embodiment is used except that the drive circuit 5A is used to output an AC signal based on a sine wave of a potential across a positive potential and a negative potential to the Peltier element 37 of the flow sensor 3A as the drive signal. The configuration is the same as that of the flow meter 1.

以上の構成による第2実施形態のガス流量計1Aでは、各流速測定ユニットAの駆動回路5Aがペルチェ素子37を、正電位と負電位とに跨った電位の正弦波による交流の駆動信号で通電駆動させても、極性が正負の相互間で反転した際にペルチェ素子37を流れる電流の向きが反転し、反転前にペルチェ素子37で生じていたペルチェ効果とは逆のペルチェ効果(暖→冷、又は、冷→暖)が発生し、ペルチェ素子37の通電量の増減に対するペルチェ素子37の放出乃至吸収熱量の増減傾向には、ペルチェ素子37を流れる電流の向きの反転の前後に亘って逆転現象が発生しないので、各流速測定ユニットAのペルチェ素子37により放出又は吸収される熱を検出したサーモパイル35が出力する流速信号の波形は、駆動信号が、その極性が正負の相互間で反転する交流信号であるか、それとも、その極性が正負の相互間で反転しない直流(シフト)信号であるかに拘わらず、駆動信号と同じ周波数の正弦波状となる。   In the gas flowmeter 1A of the second embodiment having the above configuration, the drive circuit 5A of each flow velocity measuring unit A energizes the Peltier element 37 with an alternating drive signal by a sine wave of a potential straddling a positive potential and a negative potential. Even if it is driven, the direction of the current flowing through the Peltier element 37 is reversed when the polarity is reversed between the positive and negative, and the Peltier effect (warm → cold) opposite to the Peltier effect generated in the Peltier element 37 before the reversal. Or cold / warm), and the increase / decrease tendency of the emission or absorption heat amount of the Peltier element 37 with respect to the increase / decrease of the energization amount of the Peltier element 37 is reversed before and after the reversal of the direction of current flowing through the Peltier element 37. Since the phenomenon does not occur, the waveform of the flow velocity signal output from the thermopile 35 that detects the heat released or absorbed by the Peltier element 37 of each flow velocity measurement unit A is the drive signal whose polarity is Whether the AC signal is inverted between positive and negative mutual, or its polarity regardless of whether the non inverting DC (shift) signal between positive and negative mutual, a sinusoidal with the same frequency as the drive signal.

そして、各流速測定ユニットAのサーモパイル35が出力する流速信号の波形は、流路Sを流れるガスの流速が速ければ速いほど、位相が進んで駆動信号に対する位相の遅れが縮小し、かつ、振幅が増加するように変形するので、駆動回路5の駆動信号の位相に対するバンドパスフィルタ9を通過した流速信号の位相の差に応じたHレベルの期間を有する、各流速測定ユニットAの位相差検出回路11からの位相差検出信号のディーティー比は、流路Sを流れるガスの流速を反映した値となる。   The waveform of the flow velocity signal output from the thermopile 35 of each flow velocity measuring unit A is such that the higher the flow velocity of the gas flowing through the flow path S, the more the phase is advanced and the phase delay with respect to the drive signal is reduced. The phase difference detection of each flow velocity measuring unit A has an H level period corresponding to the phase difference of the flow velocity signal that has passed through the band-pass filter 9 with respect to the phase of the drive signal of the drive circuit 5. The duty ratio of the phase difference detection signal from the circuit 11 is a value reflecting the flow velocity of the gas flowing through the flow path S.

さらに、3つの流速測定ユニットAの駆動回路5からペルチェ素子37に各々出力される駆動信号の位相が1/3ずつ互いにずれていることから、各流速測定ユニットAの位相差検出回路11のRSフリップフロップF/FからHレベルの位相差検出信号が出力される期間も、駆動信号の一周期の1/3ずつずれることになる。   Furthermore, since the phases of the drive signals output from the drive circuits 5 of the three flow velocity measuring units A to the Peltier element 37 are shifted from each other by 1/3, the RS of the phase difference detection circuit 11 of each flow velocity measuring unit A The period during which the H-level phase difference detection signal is output from the flip-flop F / F is also shifted by 1/3 of one cycle of the drive signal.

このため、各流速測定ユニットAの位相差検出回路11から駆動信号の一周期の1/3ずつずれて出力される位相差検出信号を取り込んだ演算装置13において、内部のメモリに記憶されたデータに基づいて、流路Sを流れるガスの流速乃至流量が、駆動信号の一周期の1/3の周期毎に測定されることになる。   For this reason, the data stored in the internal memory in the arithmetic unit 13 that has fetched the phase difference detection signal output from the phase difference detection circuit 11 of each flow velocity measurement unit A with a shift of 1/3 of one cycle of the drive signal. Based on the above, the flow rate or flow rate of the gas flowing through the flow path S is measured every 1/3 period of one period of the drive signal.

よって、第2実施形態のガス流量計1Aにおいても、第1実施形態のガス流量計1と同様に、流速測定の分解能を高めるためにRSフリップフロップF/Fのクロック周期を短くすることができず、その代わりに駆動回路5が出力する駆動信号の周波数を低く(周期を長く)することになっても、駆動信号の一周期の1/3の短い周期でガスの流速乃至流量の測定が行えるようにして、測定された位相差に基づいて求められる流路S上のガスの流速の、流路Sを流れるガスの実流速の変化に対する追従性の低下を防ぎ、ガスの流量測定の精度を確保することができる。   Therefore, in the gas flow meter 1A of the second embodiment, similarly to the gas flow meter 1 of the first embodiment, the clock cycle of the RS flip-flop F / F can be shortened in order to increase the resolution of the flow velocity measurement. Instead, even if the frequency of the drive signal output from the drive circuit 5 is lowered (the cycle is increased), the flow rate or flow rate of the gas can be measured in a cycle that is 1/3 of one cycle of the drive signal. The flow rate of the gas on the flow path S obtained based on the measured phase difference can be prevented from being lowered in the followability to the change in the actual flow speed of the gas flowing through the flow path S. Can be secured.

以上の第1実施形態のガス流量計1では、正弦波を直流シフトさせた正電位又は負電位の駆動信号によりマイクロヒータ33を駆動するものとしたが、本発明は、方形波のように一定の周期で電圧が変化する周期電圧波形の信号を直流シフトさせた正電位又は負電位の駆動信号でマイクロヒータ33を駆動する場合にも適用可能である。   In the gas flow meter 1 of the first embodiment described above, the microheater 33 is driven by a positive potential or negative potential drive signal obtained by direct-shifting a sine wave. However, the present invention is constant like a square wave. The present invention can also be applied to the case where the microheater 33 is driven by a drive signal having a positive potential or a negative potential obtained by direct-shifting a signal having a periodic voltage waveform in which the voltage changes with the period of.

そこで、上述した第1実施形態のガス流量計1の変形例に相当し、方形波を直流シフトさせた正電位又は負電位の駆動信号でマイクロヒータ33を駆動する、本発明の第3実施形態に係るガス流量計の概略構成について、図8のブロック図を参照して説明する。   Accordingly, the third embodiment of the present invention corresponds to a modification of the gas flow meter 1 of the first embodiment described above, and the microheater 33 is driven by a positive or negative potential drive signal obtained by direct-shifting a square wave. A schematic configuration of the gas flowmeter according to the present invention will be described with reference to the block diagram of FIG.

図8中引用符号1Bで示す第3実施形態のガス流量計は、第1実施形態のガス流量計1の各流速測定ユニットAについて、駆動回路5に代えて、方形波を直流シフトさせた正電位又は負電位の駆動信号によりマイクロヒータ33を駆動する駆動回路5B(請求項中の駆動手段に相当)を用いた点を除くと、その他は第1実施形態のガス流量計1と同様に構成されている。   The gas flow meter of the third embodiment indicated by reference numeral 1B in FIG. 8 is a positive flow rate measurement unit A of the gas flow meter 1 of the first embodiment, in which a square wave is DC-shifted instead of the drive circuit 5. Except for the point of using a drive circuit 5B (corresponding to the drive means in the claims) for driving the microheater 33 by a drive signal of potential or negative potential, the other configuration is the same as the gas flow meter 1 of the first embodiment. Has been.

そして、駆動回路5Bとしては、改めて図示しての説明は省略するものの、例えば周知の無安定マルチバイブレータを用いることができる。   As the drive circuit 5B, although not shown and described again, for example, a known astable multivibrator can be used.

以上の構成による第3実施形態のガス流量計1Bでは、各流速測定ユニットAの駆動回路5Bがマイクロヒータ33を通電駆動させるのに用いる、方形波を直流シフトさせた正電位又は負電位の駆動信号は、極性が正負の相互間で反転せず単にその電位が方形波状に変化するだけであり、したがって、マイクロヒータ33の通電量も方形波状に増減されるので、マイクロヒータ33からの放出熱量は、立ち上がり及び立ち下がりに若干の遅延による変形が生じた方形波状となり、各流速測定ユニットAのマイクロヒータ33から放出される熱を検出したサーモパイル35が出力する流速信号の波形も、駆動信号と同じ周波数の立ち上がり及び立ち下がりに若干の遅延による変形が生じた方形波状となる。   In the gas flow meter 1B of the third embodiment having the above-described configuration, the driving circuit 5B of each flow velocity measuring unit A is used to drive the microheater 33 by energization. The signal does not invert between the positive and negative polarities, and the potential merely changes in a square wave shape. Therefore, the energization amount of the microheater 33 is also increased or decreased in a square wave shape. The waveform of the flow velocity signal output from the thermopile 35 that detects the heat released from the micro heater 33 of each flow velocity measurement unit A is also a drive signal. It becomes a square wave shape in which deformation due to a slight delay occurs at the rise and fall of the same frequency.

ところで、方形波を直流シフトさせた正電位又は負電位のマイクロヒータ33の駆動信号は、基本周波数成分に加えて高調波成分を含んでいるので、各流速測定ユニットAのサーモパイル35が出力する方形波状の流速信号にも、駆動回路5Bが各流速測定ユニットAのマイクロヒータ33を通電駆動させるのに用いる駆動信号と同様に、基本周波数以外の高調波成分が含まれているが、流速の変化に対する流速信号の位相差の変化量は流速信号の周波数に依存して定まるため、基本周波数以外の高調波成分を含んでいるサーモパイル35からの流速信号をそのままの波形で使用したのでは、位相差検出回路11における駆動信号との位相差検出を正確に行うことができない。   By the way, since the drive signal of the positive potential or negative potential micro heater 33 obtained by DC-shifting the square wave includes a harmonic component in addition to the fundamental frequency component, the square output from the thermopile 35 of each flow velocity measuring unit A is output. The wavy flow velocity signal also includes harmonic components other than the fundamental frequency, like the drive signal used by the drive circuit 5B to energize and drive the micro heater 33 of each flow velocity measurement unit A. Since the amount of change in the phase difference of the flow velocity signal with respect to the flow velocity signal is determined depending on the frequency of the flow velocity signal, if the flow velocity signal from the thermopile 35 containing harmonic components other than the fundamental frequency is used as it is, the phase difference The detection circuit 11 cannot accurately detect the phase difference from the drive signal.

しかし、この流速信号に含まれる高調波成分はバンドパスフィルタ9において除去されるので、各流速測定ユニットAの位相差検出回路11に入力されるのは、駆動信号の基本周波数による正弦波となる。   However, since the harmonic component contained in this flow velocity signal is removed by the bandpass filter 9, what is input to the phase difference detection circuit 11 of each flow velocity measurement unit A is a sine wave based on the fundamental frequency of the drive signal. .

そして、各流速測定ユニットAのサーモパイル35が出力してバンドバスフィルタ9を通過した正弦波の流速信号は、流路Sを流れるガスの流速が速ければ速いほど、位相が進んで駆動信号に対する位相の遅れが縮小し、かつ、振幅が増加するように変形するので、駆動回路5Bの駆動信号の位相に対するバンドパスフィルタ9を通過した流速信号の位相の差に応じたHレベルの期間を有する、各流速測定ユニットAの位相差検出回路11からの位相差検出信号のディーティー比は、流路Sを流れるガスの流速を反映した値となる。   The sine wave flow velocity signal output from the thermopile 35 of each flow velocity measurement unit A and passed through the band-pass filter 9 is advanced in phase as the flow velocity of the gas flowing through the flow path S is higher, and the phase relative to the drive signal is increased. The delay is reduced and the amplitude is increased so that the phase of the flow rate signal passing through the band-pass filter 9 with respect to the phase of the drive signal of the drive circuit 5B has an H level period. The duty ratio of the phase difference detection signal from the phase difference detection circuit 11 of each flow velocity measurement unit A is a value reflecting the flow velocity of the gas flowing through the flow path S.

このため、各流速測定ユニットAの位相差検出回路11から駆動信号の一周期の1/3ずつずれて出力される位相差検出信号を取り込んだ演算装置13において、内部のメモリに記憶されたデータに基づいて、流路Sを流れるガスの流速乃至流量が、駆動信号の一周期の1/3の周期毎に測定されることになる。   For this reason, the data stored in the internal memory in the arithmetic unit 13 that has fetched the phase difference detection signal output from the phase difference detection circuit 11 of each flow velocity measurement unit A with a shift of 1/3 of one cycle of the drive signal. Based on the above, the flow rate or flow rate of the gas flowing through the flow path S is measured every 1/3 period of one period of the drive signal.

よって、第3実施形態のガス流量計1Bにおいても、第1実施形態のガス流量計1と同様に、流速測定の分解能を高めるためにRSフリップフロップF/Fのクロック周期を短くすることができず、その代わりに駆動回路5Bが出力する駆動信号の周波数を低く(周期を長く)することになっても、駆動信号の一周期の1/3の短い周期でガスの流速乃至流量の測定が行えるようにして、測定された位相差に基づいて求められる流路S上のガスの流速の、流路Sを流れるガスの実流速の変化に対する追従性の低下を防ぎ、ガスの流量測定の精度を確保することができる。   Therefore, in the gas flow meter 1B of the third embodiment, similarly to the gas flow meter 1 of the first embodiment, the clock cycle of the RS flip-flop F / F can be shortened in order to increase the resolution of the flow velocity measurement. Instead, even if the frequency of the drive signal output from the drive circuit 5B is lowered (the cycle is increased), the flow rate or flow rate of the gas can be measured in a short cycle of 1/3 of one cycle of the drive signal. The flow rate of the gas on the flow path S obtained based on the measured phase difference can be prevented from being lowered in the followability to the change in the actual flow speed of the gas flowing through the flow path S. Can be secured.

また、以上の第2実施形態のガス流量計1Aでは、正電位と負電位とに跨った電位の正弦波による交流の駆動信号によりマイクロヒータ33を駆動するものとしたが、本発明は、方形波のように一定の周期で電圧が変化する周期電圧波形の、正電位と負電位とに跨った電位の交流の駆動信号でペルチェ素子37を駆動する場合にも適用可能である。   In the gas flowmeter 1A of the second embodiment described above, the microheater 33 is driven by an AC drive signal by a sine wave of a potential straddling a positive potential and a negative potential. The present invention can also be applied to the case where the Peltier element 37 is driven by an AC drive signal having a potential that straddles a positive potential and a negative potential in a periodic voltage waveform in which the voltage changes at a constant cycle such as a wave.

そこで、上述した第2実施形態のガス流量計1Aの変形例に相当し、正電位と負電位とに跨った電位の方形波による交流の駆動信号でペルチェ素子37を駆動する、本発明の第4実施形態に係るガス流量計の概略構成について、図9のブロック図を参照して説明する。   Accordingly, this corresponds to a modification of the gas flow meter 1A of the second embodiment described above, and the Peltier element 37 is driven by an alternating drive signal by a square wave of a potential across a positive potential and a negative potential. A schematic configuration of the gas flowmeter according to the fourth embodiment will be described with reference to the block diagram of FIG.

図9中引用符号1Cで示す第4実施形態のガス流量計は、第2実施形態のガス流量計1Aの各流速測定ユニットAについて、駆動回路5Aに代えて、第3実施形態のガス流量計1Bの駆動回路5Bから直流シフト用の構成を省略して正電位と負電位とに跨った電位の方形波による交流信号を、前記駆動信号として前記フローセンサ3Aのペルチェ素子37に出力する駆動回路5C(請求項中の駆動手段に相当)を用いた点を除くと、その他は第2実施形態のガス流量計1Bと同様に構成されている。   The gas flow meter of the fourth embodiment shown by reference numeral 1C in FIG. 9 is the gas flow meter of the third embodiment, instead of the drive circuit 5A, for each flow velocity measuring unit A of the gas flow meter 1A of the second embodiment. A driving circuit that omits the DC shift configuration from the driving circuit 5B of 1B and outputs an AC signal by a square wave of a potential straddling a positive potential and a negative potential to the Peltier element 37 of the flow sensor 3A as the driving signal. Except for the point using 5C (corresponding to the driving means in the claims), the rest is configured in the same manner as the gas flow meter 1B of the second embodiment.

そして、駆動回路5Cとしては、改めて図示しての説明は省略するものの、例えば周知の無安定マルチバイブレータを用いることができる。   As the drive circuit 5C, for example, a well-known astable multivibrator can be used, although the illustration and illustration are omitted.

以上の構成による第4実施形態のガス流量計1Cでは、各流速測定ユニットAの駆動回路5Cがペルチェ素子37を、正電位と負電位とに跨った電位の方形波による交流の駆動信号で通電駆動させても、極性が正負の相互間で反転した際にペルチェ素子37を流れる電流の向きが反転し、反転前にペルチェ素子37で生じていたペルチェ効果とは逆のペルチェ効果(暖→冷、又は、冷→暖)が発生し、ペルチェ素子37の通電量の増減に対するペルチェ素子37の放出乃至吸収熱量の増減傾向には、ペルチェ素子37を流れる電流の向きの反転の前後に亘って逆転現象が発生しないので、各流速測定ユニットAのペルチェ素子37により放出又は吸収される熱を検出したサーモパイル35が出力する流速信号の波形は、駆動信号が、その極性が正負の相互間で反転する交流信号であるか、それとも、その極性が正負の相互間で反転しない直流(シフト)信号であるかに拘わらず、駆動信号と同じ周波数の立ち上がり及び立ち下がりに若干の遅延による変形が生じた方形波状となる。   In the gas flow meter 1C of the fourth embodiment having the above-described configuration, the drive circuit 5C of each flow velocity measurement unit A energizes the Peltier element 37 with an alternating drive signal by a square wave of a potential straddling a positive potential and a negative potential. Even if it is driven, the direction of the current flowing through the Peltier element 37 is reversed when the polarity is reversed between the positive and negative, and the Peltier effect (warm → cold) opposite to the Peltier effect generated in the Peltier element 37 before the reversal. Or cold / warm), and the increase / decrease tendency of the emission or absorption heat amount of the Peltier element 37 with respect to the increase / decrease of the energization amount of the Peltier element 37 is reversed before and after the reversal of the direction of current flowing through the Peltier element 37. Since the phenomenon does not occur, the waveform of the flow velocity signal output from the thermopile 35 that detects the heat released or absorbed by the Peltier element 37 of each flow velocity measurement unit A is the drive signal whose polarity is Regardless of whether the signal is an AC signal that is inverted between positive and negative or a DC signal that is not inverted between the positive and negative polarities (shift), there is a slight rise and fall at the same frequency as the drive signal. It becomes a square wave with deformation caused by delay.

ところで、正電位と負電位とに跨った電位の方形波によるペルチェ素子37の駆動信号は、基本周波数成分に加えて高調波成分を含んでいるので、各流速測定ユニットAのサーモパイル35が出力する方形波状の流速信号にも、駆動回路5Cが各流速測定ユニットAのペルチェ素子37を通電駆動させるのに用いる駆動信号と同様に、基本周波数以外の高調波成分が含まれているが、流速の変化に対する流速信号の位相差の変化量は流速信号の周波数に依存して定まるため、基本周波数以外の高調波成分を含んでいるサーモパイル35からの流速信号をそのままの波形で使用したのでは、位相差検出回路11における駆動信号との位相差検出を正確に行うことができない。   By the way, since the drive signal of the Peltier element 37 by the square wave of the potential straddling the positive potential and the negative potential includes the harmonic component in addition to the fundamental frequency component, the thermopile 35 of each flow velocity measuring unit A outputs. Similarly to the drive signal used for the drive circuit 5C to energize and drive the Peltier element 37 of each flow velocity measurement unit A, the square wave flow velocity signal includes harmonic components other than the fundamental frequency. Since the amount of change in the phase difference of the flow velocity signal with respect to the change is determined depending on the frequency of the flow velocity signal, the flow velocity signal from the thermopile 35 containing harmonic components other than the fundamental frequency is used as it is in the waveform. The phase difference with the drive signal in the phase difference detection circuit 11 cannot be accurately detected.

しかし、この流速信号に含まれる高調波成分はバンドパスフィルタ9において除去されるので、各流速測定ユニットAの位相差検出回路11に入力されるのは、駆動信号の基本周波数による正弦波となる。   However, since the harmonic component contained in this flow velocity signal is removed by the bandpass filter 9, what is input to the phase difference detection circuit 11 of each flow velocity measurement unit A is a sine wave based on the fundamental frequency of the drive signal. .

そして、各流速測定ユニットAのサーモパイル35が出力してバンドバスフィルタ9を通過した正弦波の流速信号は、流路Sを流れるガスの流速が速ければ速いほど、位相が進んで駆動信号に対する位相の遅れが縮小し、かつ、振幅が増加するように変形するので、駆動回路5Cの駆動信号の位相に対するバンドパスフィルタ9を通過した流速信号の位相の差に応じたHレベルの期間を有する、各流速測定ユニットAの位相差検出回路11からの位相差検出信号のディーティー比は、流路Sを流れるガスの流速を反映した値となる。   The sine wave flow velocity signal output from the thermopile 35 of each flow velocity measurement unit A and passed through the band-pass filter 9 is advanced in phase as the flow velocity of the gas flowing through the flow path S is higher, and the phase relative to the drive signal is increased. The delay is reduced and the amplitude is increased so that the phase of the flow rate signal passing through the band-pass filter 9 with respect to the phase of the drive signal of the drive circuit 5C has an H level period. The duty ratio of the phase difference detection signal from the phase difference detection circuit 11 of each flow velocity measurement unit A is a value reflecting the flow velocity of the gas flowing through the flow path S.

このため、各流速測定ユニットAの位相差検出回路11から駆動信号の一周期の1/3ずつずれて出力される位相差検出信号を取り込んだ演算装置13において、内部のメモリに記憶されたデータに基づいて、流路Sを流れるガスの流速乃至流量が、駆動信号の一周期の1/3の周期毎に測定されることになる。   For this reason, the data stored in the internal memory in the arithmetic unit 13 that has fetched the phase difference detection signal output from the phase difference detection circuit 11 of each flow velocity measurement unit A with a shift of 1/3 of one cycle of the drive signal. Based on the above, the flow rate or flow rate of the gas flowing through the flow path S is measured every 1/3 period of one period of the drive signal.

よって、第4実施形態のガス流量計1Cにおいても、第2実施形態のガス流量計1Aと同様に、流速測定の分解能を高めるためにRSフリップフロップF/Fのクロック周期を短くすることができず、その代わりに駆動回路5Cが出力する駆動信号の周波数を低く(周期を長く)することになっても、駆動信号の一周期の1/3の短い周期でガスの流速乃至流量の測定が行えるようにして、測定された位相差に基づいて求められる流路S上のガスの流速の、流路Sを流れるガスの実流速の変化に対する追従性の低下を防ぎ、ガスの流量測定の精度を確保することができる。   Therefore, in the gas flow meter 1C of the fourth embodiment, similarly to the gas flow meter 1A of the second embodiment, the clock cycle of the RS flip-flop F / F can be shortened in order to increase the resolution of the flow velocity measurement. Instead, even if the frequency of the drive signal output from the drive circuit 5C is lowered (longer cycle), the flow rate or flow rate of the gas can be measured in a cycle shorter than 1/3 of one cycle of the drive signal. The flow rate of the gas on the flow path S obtained based on the measured phase difference can be prevented from being lowered in the followability to the change in the actual flow speed of the gas flowing through the flow path S. Can be secured.

ちなみに、第1実施形態のガス流量計1で用いた各流速測定ユニットAの駆動回路5は、第2実施形態のガス流量計1Aの各流速測定ユニットAで用いた、駆動回路5から直流シフト用のアンプ53を省略して正電位と負電位とに跨った電位の正弦波による交流信号を駆動信号として出力する駆動回路5Aに替えてもよい。   Incidentally, the drive circuit 5 of each flow velocity measurement unit A used in the gas flow meter 1 of the first embodiment is DC-shifted from the drive circuit 5 used in each flow velocity measurement unit A of the gas flow meter 1A of the second embodiment. The amplifier 53 may be omitted and replaced with the drive circuit 5A that outputs an AC signal as a drive signal by a sine wave having a potential straddling a positive potential and a negative potential.

その場合には、各流速測定ユニットAの駆動回路5Aがマイクロヒータ33を通電駆動させるのに用いる正弦波の駆動信号は、極性が正負の相互間で反転し、マイクロヒータ33の通電量が所謂半波整流波形状になり、電流と電圧の積である電力に比例するマイクロヒータ33の放熱量は、マイクロヒータ33の通電駆動に用いる駆動信号の2倍の周波数を持つ正弦波となるので、マイクロヒータ33から放出される熱を検出した各流速測定ユニットAのサーモパイル35が出力する流速信号の波形は、マイクロヒータ33の放出熱量に追従して、駆動信号の倍の周波数の正弦波となる。   In that case, the sine wave drive signal used by the drive circuit 5A of each flow velocity measurement unit A to drive the microheater 33 is reversed between the positive and negative polarities, and the current flow of the microheater 33 is so-called. Since the heat dissipation amount of the microheater 33, which has a half-wave rectified wave shape and is proportional to the power that is the product of current and voltage, becomes a sine wave having a frequency twice that of the drive signal used for energization driving of the microheater 33, The waveform of the flow velocity signal output from the thermopile 35 of each flow velocity measurement unit A that has detected the heat released from the microheater 33 follows the amount of heat released from the microheater 33 and becomes a sine wave having a frequency twice that of the drive signal. .

このため、各流速測定ユニットAの位相差検出回路11では、駆動信号と、駆動信号の倍の周波数の正弦波となるサーモパイル35からの流速信号との位相差が検出されることになる。   Therefore, the phase difference detection circuit 11 of each flow velocity measuring unit A detects the phase difference between the drive signal and the flow velocity signal from the thermopile 35 that is a sine wave having a frequency twice that of the drive signal.

よって、第1実施形態のガス流量計1において、駆動回路5Aによりマイクロヒータ33を通電駆動するように構成しても、第1実施形態のガス流量計1と同様の効果を得ることができる。   Therefore, even if the gas flow meter 1 of the first embodiment is configured such that the microheater 33 is energized and driven by the drive circuit 5A, the same effect as the gas flow meter 1 of the first embodiment can be obtained.

尚、上記の各実施形態では、サーモパイル35がマイクロヒータ33やペルチェ素子37よりも流体の流れ方向における下流側に位置する場合について説明したが、本発明は、サーモパイル35がマイクロヒータ33やペルチェ素子37よりも流体の流れ方向における上流側に位置する場合についても、適用可能である。   In each of the above embodiments, the case where the thermopile 35 is located downstream of the microheater 33 and the Peltier element 37 in the fluid flow direction has been described. However, in the present invention, the thermopile 35 is the microheater 33 and the Peltier element. The present invention can also be applied to a case where it is located upstream of 37 in the fluid flow direction.

その場合にも、サーモパイル35がマイクロヒータ33やペルチェ素子37よりも流体の流れ方向における下流側に位置する場合と同じく、サーモパイル35が出力する流速信号の波形は、流路Sを流れるガスの流速が速ければ速いほど、位相が進んで駆動信号に対する位相の遅れが縮小するように変形するので、駆動回路5,5A,5B,5Cの駆動信号の位相に対するバンドパスフィルタ9を通過した流速信号の位相の差に応じたHレベルの期間を有する位相差検出回路11からの位相差検出信号のディーティー比は、流路Sを流れるガスの流速を反映した値となる。   Also in this case, the waveform of the flow velocity signal output from the thermopile 35 is the flow velocity of the gas flowing through the flow path S, as in the case where the thermopile 35 is located downstream of the micro heater 33 and the Peltier element 37 in the fluid flow direction. The higher the speed is, the more the phase is advanced and the phase delay with respect to the drive signal is reduced so that the phase of the flow rate signal that has passed through the band-pass filter 9 with respect to the phase of the drive signal of the drive circuits 5, 5A, 5B, 5C. The duty ratio of the phase difference detection signal from the phase difference detection circuit 11 having an H level period corresponding to the phase difference is a value reflecting the flow velocity of the gas flowing through the flow path S.

このため、サーモパイル35がマイクロヒータ33よりも流体の流れ方向における上流側に位置する場合でも、第1乃至第4実施形態のガス流量計1,1A,1B,1Cにおける各流速測定ユニットAの位相差検出回路11からの位相差検出信号を取り込んだ演算装置13において、内部のメモリに記憶されたデータに基づいて、流路Sを流れるガスの流速乃至流量を、駆動信号の一周期の1/3の周期毎に高精度で測定することができる。   For this reason, even when the thermopile 35 is located upstream of the micro heater 33 in the fluid flow direction, the position of each flow velocity measurement unit A in the gas flow meters 1, 1A, 1B, 1C of the first to fourth embodiments. In the arithmetic unit 13 that has captured the phase difference detection signal from the phase difference detection circuit 11, the flow rate or flow rate of the gas flowing through the flow path S is set to 1 / cycle of one cycle of the drive signal based on the data stored in the internal memory. It is possible to measure with high accuracy every three periods.

また、以上の第1乃至第4実施形態のガス流量計1,1A,1B,1Cでは、3つのフローセンサ3,3Aを、流路Sにおけるガスの流れる条件が等しい箇所に、各々離して配置し、各フローセンサ3,3Aの間隔を利用して、各フローセンサ3のマイクロヒータ33が発する熱や、各フローセンサ3Aのペルチェ素子37が放出又は吸収する熱が、他のフローセンサ3,3Aのサーモパイル35によって感知されることのないように構成した。   Further, in the gas flowmeters 1, 1A, 1B, and 1C of the first to fourth embodiments described above, the three flow sensors 3 and 3A are arranged separately at locations where the gas flow conditions in the flow path S are equal. The heat generated by the micro heater 33 of each flow sensor 3 or the heat released or absorbed by the Peltier element 37 of each flow sensor 3A is converted into the other flow sensors 3, 3A using the interval between the flow sensors 3 and 3A. It was configured not to be sensed by the 3A thermopile 35.

しかし、図10に説明図で示すように、3つのフローセンサ3,3AのSi基台31どうしを連結して一体化したフローセンサユニットBを、流路S上に、マイクロヒータ33が流体の流れ方向における上流側に、サーモパイル35やサーモパイル35が下流側に位置するように配置することで、3つのフローセンサ3,3Aを流路Sにおけるガスの流れる条件が等しい箇所に各々配置する構成としてもよい。   However, as shown in the explanatory diagram of FIG. 10, the flow sensor unit B in which the Si bases 31 of the three flow sensors 3, 3 </ b> A are connected and integrated is connected to the flow path S with the micro heater 33 being a fluid. By arranging the thermopile 35 and the thermopile 35 on the upstream side in the flow direction so as to be located on the downstream side, the three flow sensors 3 and 3A are arranged at locations where the gas flow conditions in the flow path S are equal. Also good.

この場合、各フローセンサ3,3Aのサーモパイル35は、他のフローセンサ3,3Aのマイクロヒータ33が発する熱やペルチェ素子37が放出又は吸収する熱に対して、一体に連結されたそれぞれのSi基板31によって熱的に絶縁すればよい。   In this case, the thermopile 35 of each flow sensor 3, 3 </ b> A is connected to each Si that is integrally connected to the heat generated by the micro heater 33 of the other flow sensor 3, 3 </ b> A and the heat released or absorbed by the Peltier element 37. What is necessary is just to thermally insulate with the board | substrate 31.

そして、このように構成すれば、各フローセンサ3,3Aを容易に流路Sにおけるガスの流れる条件が等しい箇所に各々配置することができる。   And if comprised in this way, each flow sensor 3 and 3A can each be easily arrange | positioned in the location where the conditions where the gas flows in the flow path S are equal.

さらに、上記の各実施形態ではフローセンサ3,3Aを3つ用い、各フローセンサ3,3Aる場合について説明したが、フローセンサ3,3Aのマイクロヒータ33やペルチェ素子37を、流速測定ユニットAの個数分の1である1/3ずつ互いの位相をずらした駆動信号により各々通電駆動する場合について説明したが、フローセンサ3,3Aの数は2つ以上であればいくつであっても良く、各フローセンサ3,3Aのマイクロヒータ33やペルチェ素子37の通電駆動に使用する駆動信号は、使用するフローセンサ3,3Aの個数分の1(n個のフローセンサ3,3Aを使用する場合は1/n)ずつ互いの位相をずらせばよい。   Further, in each of the above embodiments, the case where the three flow sensors 3 and 3A are used and the flow sensors 3 and 3A are used has been described. However, the micro heater 33 and the Peltier element 37 of the flow sensors 3 and 3A are connected to the flow velocity measurement unit A. In the above description, the energization driving is performed using the drive signals whose phases are shifted by 1/3, which is one-third of the number of the flow sensors. However, the number of the flow sensors 3 and 3A may be any number as long as it is two or more. The drive signal used for energization driving of the micro heater 33 and the Peltier element 37 of each flow sensor 3, 3 A is 1 / the number of the flow sensors 3, 3 A to be used (when n flow sensors 3, 3 A are used) Can be shifted by 1 / n).

また、上記の各実施形態ではガスの流量を測定するガス流量計を例に取って説明したが、本発明は、ガス以外の気体や液体等、様々な流体の流速乃至流量測定について適用可能であり、また、流量を測定せずその前段階の流速のみ測定する場合についても、広く適用可能であることは言うまでもない。   In each of the above embodiments, the gas flowmeter for measuring the gas flow rate has been described as an example. However, the present invention is applicable to the measurement of the flow rate or flow rate of various fluids such as gases and liquids other than gas. In addition, it goes without saying that the present invention can be widely applied to the case where only the flow velocity at the previous stage is measured without measuring the flow rate.

本発明の第1及び第3実施形態に係るガス流量計において使用されるフローセンサの概略構成を示す説明図である。It is explanatory drawing which shows schematic structure of the flow sensor used in the gas flowmeter which concerns on 1st and 3rd embodiment of this invention. 図1に示すフローセンサの断面図である。It is sectional drawing of the flow sensor shown in FIG. 本発明による流速計を適用した本発明の第1実施形態に係るガス流量計の概略構成を示すブロック図である。It is a block diagram which shows schematic structure of the gas flowmeter which concerns on 1st Embodiment of this invention to which the current meter by this invention is applied. 図3の駆動回路の内部構成を示す回路図である。FIG. 4 is a circuit diagram showing an internal configuration of the drive circuit of FIG. 3. 図3の位相差検出回路の内部構成を示す回路図である。FIG. 4 is a circuit diagram showing an internal configuration of the phase difference detection circuit of FIG. 3. 本発明の第3及び第4実施形態に係るガス流量計において使用されるフローセンサの概略構成を示す説明図である。It is explanatory drawing which shows schematic structure of the flow sensor used in the gas flowmeter which concerns on 3rd and 4th embodiment of this invention. 本発明による流速計を適用した本発明の第2実施形態に係るガス流量計の概略構成を示すブロック図である。It is a block diagram which shows schematic structure of the gas flowmeter which concerns on 2nd Embodiment of this invention to which the current meter by this invention is applied. 本発明による流速計を適用した本発明の第3実施形態に係るガス流量計の概略構成を示すブロック図である。It is a block diagram which shows schematic structure of the gas flowmeter which concerns on 3rd Embodiment of this invention to which the current meter by this invention is applied. 本発明による流速計を適用した本発明の第4実施形態に係るガス流量計の概略構成を示すブロック図である。It is a block diagram which shows schematic structure of the gas flowmeter which concerns on 4th Embodiment of this invention to which the current meter by this invention is applied. 本発明の他の実施形態に係るガス流量計において使用されるフローセンサの概略構成を示す説明図である。It is explanatory drawing which shows schematic structure of the flow sensor used in the gas flowmeter which concerns on other embodiment of this invention.

符号の説明Explanation of symbols

1,1A,1B,1C ガス流量計
3,3A フローセンサ
5,5A,5B,5C 駆動回路(駆動手段)
11 位相差検出回路(位相差信号出力手段)
31 Si基板(シリコン基台、熱絶縁手段)
32 絶縁層膜
32a ダイヤフラム領域
33 マイクロヒータ(熱源)
35 サーモパイル(温度センサ)
37 ペルチェ素子(熱源)
S 流路
1, 1A, 1B, 1C Gas flow meter 3, 3A Flow sensor 5, 5A, 5B, 5C Drive circuit (drive means)
11 Phase difference detection circuit (phase difference signal output means)
31 Si substrate (silicon base, thermal insulation means)
32 Insulating layer film 32a Diaphragm region 33 Micro heater (heat source)
35 Thermopile (temperature sensor)
37 Peltier element (heat source)
S channel

Claims (3)

一定の周期で電圧が変化する周期電圧波形の駆動信号により通電駆動される熱源と、該熱源が放出又は吸収する熱を検出しその温度に応じた流速信号を出力する温度センサとを有するフローセンサを、被測定対象の流体の流路上に、前記熱源と前記温度センサとが前記流路における流体の流れ方向に間隔をおくように配置し、前記流速信号と前記駆動信号との位相差を検出した位相差信号出力手段が該位相差に応じて出力する位相差信号に基づいて、前記流路を流れる流体の流速を測定する流速計において、
前記流路の前記流体の流れる条件が等しいn箇所(n=2以上の整数)に各々配置される前記フローセンサと、
前記各フローセンサを相互に熱的に絶縁する熱絶縁手段と、
前記各フローセンサの前記熱源を、前記駆動信号の1/n周期ずつ互いに位相をずらした前記駆動信号により各々通電駆動する駆動手段とを備えており、
前記駆動信号の1/n周期おきに順次前記位相差信号出力手段により検出される前記各フローセンサ毎の前記流速信号と前記駆動信号との位相差に応じた前記位相差信号に基づいて、前記流路を流れる流体の流速を、前記駆動信号の1/n周期おきに測定する、
ことを特徴とする流速計。
A flow sensor having a heat source that is energized and driven by a drive signal having a periodic voltage waveform whose voltage changes at a constant period, and a temperature sensor that detects heat released or absorbed by the heat source and outputs a flow rate signal according to the temperature Is disposed on the flow path of the fluid to be measured so that the heat source and the temperature sensor are spaced apart from each other in the flow direction of the fluid in the flow path, and the phase difference between the flow velocity signal and the drive signal is detected. In the velocimeter for measuring the flow velocity of the fluid flowing through the flow path based on the phase difference signal output by the phase difference signal output means according to the phase difference,
The flow sensors respectively arranged at n locations (n = 2 or more integers) where the fluid flows in the flow path are equal;
Thermal insulation means for thermally insulating the flow sensors from each other;
Drive means for energizing and driving the heat sources of the flow sensors by the drive signals that are out of phase with each other by 1 / n period of the drive signal,
Based on the phase difference signal corresponding to the phase difference between the flow velocity signal and the drive signal for each flow sensor detected by the phase difference signal output means sequentially every 1 / n cycle of the drive signal, Measuring the flow velocity of the fluid flowing through the flow path every 1 / n period of the drive signal;
An anemometer characterized by that.
前記各フローセンサは、前記熱源及び前記温度センサが配置される絶縁層膜と、該絶縁層膜の前記熱源及び前記温度センサが配置されたダイヤフラム領域の周縁領域にシリコン基台を設けて構成されていて、前記シリコン基台どうしを連結することでn個の前記フローセンサが一体に形成されており、前記熱絶縁手段は、前記各フローセンサの前記シリコン基台によって構成されている請求項1記載の流速計。   Each flow sensor is configured by providing a silicon base in a peripheral region of the insulating layer film in which the heat source and the temperature sensor are disposed, and a diaphragm region of the insulating layer film in which the heat source and the temperature sensor are disposed. The n flow sensors are integrally formed by connecting the silicon bases, and the thermal insulation means is constituted by the silicon bases of the flow sensors. The anemometer described. 一定の周期で電圧が変化する周期電圧波形の駆動信号により通電駆動される熱源と、該熱源が放出又は吸収する熱を検出しその温度に応じた流速信号を出力する温度センサとを有するフローセンサを、被測定対象の流体の流路上に、前記熱源と前記温度センサとが前記流路における流体の流れ方向に間隔をおくように配置し、前記流速信号と前記駆動信号との位相差を検出した位相差信号出力手段が該位相差に応じて出力する位相差信号に基づいて、前記流路を流れる流体の流量を測定する流量計であって、
請求項1又は2記載の流速計を備え、
前記流速計により測定された前記流路を流れる流体の流速、及び、前記流路の既知の断面積を用いて、前記流路を流れる流体の流量を測定する、
ことを特徴とする流量計。
A flow sensor having a heat source that is energized and driven by a drive signal having a periodic voltage waveform whose voltage changes at a constant period, and a temperature sensor that detects heat released or absorbed by the heat source and outputs a flow rate signal according to the temperature Is arranged on the flow path of the fluid to be measured so that the heat source and the temperature sensor are spaced apart from each other in the flow direction of the fluid in the flow path, and the phase difference between the flow velocity signal and the drive signal is detected. A flowmeter that measures the flow rate of the fluid flowing through the flow path based on the phase difference signal output by the phase difference signal output means according to the phase difference,
The anemometer according to claim 1 or 2,
Using the flow velocity of the fluid flowing through the flow path measured by the anemometer and the known cross-sectional area of the flow path, the flow rate of the fluid flowing through the flow path is measured.
A flow meter characterized by that.
JP2005289184A 2005-09-30 2005-09-30 Current meter and flow meter Expired - Fee Related JP4571898B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2005289184A JP4571898B2 (en) 2005-09-30 2005-09-30 Current meter and flow meter

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2005289184A JP4571898B2 (en) 2005-09-30 2005-09-30 Current meter and flow meter

Publications (2)

Publication Number Publication Date
JP2007101270A JP2007101270A (en) 2007-04-19
JP4571898B2 true JP4571898B2 (en) 2010-10-27

Family

ID=38028368

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2005289184A Expired - Fee Related JP4571898B2 (en) 2005-09-30 2005-09-30 Current meter and flow meter

Country Status (1)

Country Link
JP (1) JP4571898B2 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4987548B2 (en) * 2006-04-17 2012-07-25 矢崎総業株式会社 Flowmeter

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04343024A (en) * 1991-05-20 1992-11-30 Tokico Ltd Flowrate sensor
JPH0572001A (en) * 1991-05-02 1993-03-23 Yamaha Corp Measuring device
JPH09243413A (en) * 1996-03-07 1997-09-19 Tokyo Gas Co Ltd Sensor having coating

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0572001A (en) * 1991-05-02 1993-03-23 Yamaha Corp Measuring device
JPH04343024A (en) * 1991-05-20 1992-11-30 Tokico Ltd Flowrate sensor
JPH09243413A (en) * 1996-03-07 1997-09-19 Tokyo Gas Co Ltd Sensor having coating

Also Published As

Publication number Publication date
JP2007101270A (en) 2007-04-19

Similar Documents

Publication Publication Date Title
WO2011161873A1 (en) Ultrasonic flow rate measurement device
EP1044355B1 (en) Self-oscillating fluid sensor
EP1995571A1 (en) Current velocity detection method and current velocity detector employing heat signal
US20130031973A1 (en) Method for detecting accretion or abrasion in a flow measuring device
WO2013172028A1 (en) Flow rate measurement device
JPS6161013A (en) Fluid flow-rate sensor
CN101258385A (en) Sensor unit for fluids
JP4939128B2 (en) Fluid velocity measuring device
JP4571898B2 (en) Current meter and flow meter
JP2003065820A (en) Flow-measuring instrument
JP4588604B2 (en) Current meter and flow meter
JP2006138838A (en) Current meter and flowmeter
JP2000039344A (en) Flowmeter and gas meter
JP2006138840A (en) Current meter and flowmeter
JP3822771B2 (en) Flow rate measuring method and flow rate measuring device
JPH05157603A (en) Method for correcting flow rate of flowmeter
JPH11325999A (en) Thermal flow sensor and fluid measuring method
JPH11281422A (en) Vortex flow meter
JP6537566B2 (en) Method of driving temperature sensitive device, driving device, and vortex flowmeter
JP5227061B2 (en) Flow measuring device
JP3335600B2 (en) Coriolis mass flowmeter
RU2548123C1 (en) Measurement of gas and fluid characteristics
JP2009109285A (en) Thermal flowmeter
JP2002048615A (en) Flowmeter using thermal flow sensor
JPH08136298A (en) Fluidic type gas meter

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20080903

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20100804

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20100810

A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20100813

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20130820

Year of fee payment: 3

R150 Certificate of patent or registration of utility model

Free format text: JAPANESE INTERMEDIATE CODE: R150

LAPS Cancellation because of no payment of annual fees