JP2010002268A - Microwave-type densitometer and liquid temperature correcting method thereof - Google Patents

Microwave-type densitometer and liquid temperature correcting method thereof Download PDF

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JP2010002268A
JP2010002268A JP2008160526A JP2008160526A JP2010002268A JP 2010002268 A JP2010002268 A JP 2010002268A JP 2008160526 A JP2008160526 A JP 2008160526A JP 2008160526 A JP2008160526 A JP 2008160526A JP 2010002268 A JP2010002268 A JP 2010002268A
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liquid
temperature
antenna
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Kazuhiro Watanabe
一弘 渡邉
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Toshiba Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a microwave-type densitometer capable of reducing a measuring error even if a liquid temperature suddenly changes without providing a new receiving antenna or a thermostatic control part covering the periphery of transmitting and receiving antennae, and a liquid temperature correcting method thereof. <P>SOLUTION: The microwave-type densitometer for measuring the concentration of a liquid to be measured is equipped with a temperature correcting arithmetic part which measures the liquid temperature t2 of the liquid to be measured, calculates a liquid temperature correcting value used for correcting the phase difference Δθ on the basis of the temperature difference Δt (=t2-t1) with the preliminarily measured liquid temperature t1 of the liquid containing no substance to be measured, further measures the antenna temperature ta of either one of the transmitting and receiving antennae, calculates the temperature difference between the liquid temperature t2 and the antenna temperature ta to calculate a phase difference correcting liquid temperature-antenna temperature difference correction value, and corrects the phase difference Δθ from the liquid temperature correction value and the liquid temperature-antenna temperature difference correction value to calculate the concentration of the liquid to be measured. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

本発明は、マイクロ波の伝播時間遅れに基づいて、被測定液体の濃度を測定するマイクロ波式濃度計、及びその液温補正方法に係り、特に、被測定液体の液温が急変した場合の濃度の測定誤差を軽減したマイクロ波式濃度計、及びその液温補正方法に関する。   The present invention relates to a microwave concentration meter that measures the concentration of a liquid to be measured based on a delay in the propagation time of the microwave, and a liquid temperature correction method thereof, particularly when the liquid temperature of the liquid to be measured changes suddenly. The present invention relates to a microwave densitometer that reduces concentration measurement errors and a liquid temperature correction method thereof.

従来、被測定物質を含む被測定液体の流れる配管又は被測定液体を収納した容器を介して対向配置されたマイクロ波の送受信器を備え、この送信器から発射され被測定液体を通過し受信器にて受信されたマイクロ波の位相遅れθ２と、予め被測定物質を含まない液体を用いて測定しておいた位相遅れθ１との位相差Δθを求めることにより被測定液体の濃度を測定する、マイクロ波式濃度計がある。（例えば、特許文献１参照。）。   2. Description of the Related Art Conventionally, a microwave transmitter / receiver is provided that is opposed to each other through a pipe through which a liquid to be measured containing a substance to be measured flows or a container that stores the liquid to be measured. The concentration of the liquid to be measured is measured by obtaining a phase difference Δθ between the phase delay θ2 of the microwave received at 1 and the phase delay θ1 measured in advance using a liquid not containing the substance to be measured. There is a microwave densitometer. (For example, refer to Patent Document 1).

このようなマイクロ波式濃度計は、被測定液体の誘電率が温度によって変化し、位相差△θに影響を与えることから、液温を測定して位相差Δθを補正する液温補正が行なわれている。   In such a microwave concentration meter, since the dielectric constant of the liquid to be measured changes with temperature and affects the phase difference Δθ, the liquid temperature is corrected by measuring the liquid temperature and correcting the phase difference Δθ. It is.

この液温補正は、予め液温を測定して記憶しておいた被測定物質を含まない濃度ゼロの基準液体の温度ｔｗと被測定液体の測定時の温度ｔｓとの温度差Δｔ（＝ｔｓ−ｔｗ）と、位相差補正値Δθεとの関係を予め求めておき、位相差Δθと位相差補正値Δθεとの差Δθｔ
Δθｔ＝Δθ−Δθε
を求め、この補正された位相差Δθｔと濃度との関係を予め検量線として求めておき、被測定液体の濃度を求める様にしている。 In this liquid temperature correction, the temperature difference Δt (= ts) between the temperature tw of the zero-concentration reference liquid that does not contain the substance to be measured, which has been measured and stored in advance, and the temperature ts at the time of measurement of the liquid to be measured. −tw) and the phase difference correction value Δθε in advance, and the difference Δθt between the phase difference Δθ and the phase difference correction value Δθε.
Δθt = Δθ−Δθε
The relationship between the corrected phase difference Δθt and the concentration is obtained in advance as a calibration curve, and the concentration of the liquid to be measured is obtained.

この検量線は、被測定液体の濃度が高い場合や、濃度ゼロの基準液体との液温差が大きい場合には、ゼロ点の平行移動だけの補正では不充分であることから温度に応じて誘電率が変化する被測定用液体に対し、検量線をある幅の温度範囲で分割して、その分割された範囲において所定の直線関係で近似した検量線の傾きや、検量線の切片を補正する方法がある（例えば、特許文献２参照。）。   When the concentration of the liquid to be measured is high, or when the liquid temperature difference from the zero-concentration reference liquid is large, it is not sufficient to correct only the zero point translation. For a liquid to be measured whose rate changes, divide the calibration curve in a certain temperature range and correct the slope of the calibration curve approximated by a predetermined linear relationship and the intercept of the calibration curve in the divided range. There is a method (for example, refer to Patent Document 2).

また、最近では、被測定用液体の液温が急変した場合、基準位相Δθ１を求める基準系経路の周囲温度と被測定液体の位相Δθ２を求める測定系経路の被測定用液体の液温とに温度差が発生した場合に、送信アンテナ、受信アンテナの温度応答特性の相違、及び、送受信アンテナ自身の温度ドリフトによって、マイクロ波の伝播速度が変動し測定誤差が発生する問題がある。   Further, recently, when the liquid temperature of the liquid to be measured has suddenly changed, the ambient temperature of the reference system path for obtaining the reference phase Δθ1 and the liquid temperature of the liquid to be measured for the measurement system path for obtaining the phase Δθ2 of the liquid to be measured When a temperature difference occurs, there is a problem that the propagation speed of the microwave fluctuates due to a difference in temperature response characteristics between the transmission antenna and the reception antenna and a temperature drift of the transmission / reception antenna itself, resulting in a measurement error.

さらに、受信アンテナ、送信アンテナの温度時定数は、測温抵抗体等の小熱容量金属の時定数と異なり、セラミックスなどの熱伝導率の低い誘電体で構成されるため、通常、数分〜６０分程度の時定数を有するので、液温が急変すると測定誤差が長時間発生する問題がある。   Furthermore, the temperature time constants of the receiving antenna and the transmitting antenna are different from the time constants of small heat capacity metals such as resistance temperature detectors and are composed of a dielectric material having a low thermal conductivity such as ceramics. Since it has a time constant of about a minute, there is a problem that a measurement error occurs for a long time when the liquid temperature changes suddenly.

そこで、送信アンテナからのマイクロ波の伝播距離が異なる２台の受信アンテナへの伝播位相差を求めて、送信アンテナ及び受信アンテナ間での温度変化によるマイクロ波の伝播速度の変動を除去して濃度を測定するようにしたマイクロ波式濃度計がある（例えば、特許文献３参照。）。   Therefore, the propagation phase difference between the two receiving antennas with different microwave propagation distances from the transmitting antenna is obtained, and fluctuations in the propagation speed of the microwave due to temperature changes between the transmitting antenna and the receiving antenna are removed to reduce the concentration. There is a microwave densitometer that measures the above (for example, see Patent Document 3).

また、送受信アンテナ、及び基準経路及び測定経路を含む装置の容器または配管を含む周囲を断熱材質のカバー部材により囲み、この部材の内側に設けられた温度センサにより周囲温度を測定し、該温度センサにより測定された温度測定値に基づいて、カバー部材内側の温度を一定値に調整するための発熱体または吸熱体を制御するようにしたマイクロ波式濃度計が開示されている（例えば、特許文献４。）。
特許第２９６５７１２号公報 特開２００１−２４２０９９号公報 特開２００５−８３８２１号公報 特開２００６−１８４２２３号公報 In addition, the periphery including the container or pipe of the device including the transmission / reception antenna and the reference path and the measurement path is surrounded by a cover member made of a heat insulating material, and the ambient temperature is measured by a temperature sensor provided inside the member, and the temperature sensor A microwave densitometer is disclosed that controls a heating element or an endothermic body for adjusting the temperature inside the cover member to a constant value based on the temperature measurement value measured by (for example, Patent Documents). 4)).
Japanese Patent No. 2965712 JP 2001-242099 A Japanese Patent Laying-Open No. 2005-83821 JP 2006-184223 A

しかし、特許文献３に開示されたマイクロ波式濃度計の構成では、新たにもう１つの受信アンテナを備えることが必要となる問題がある。また、特許文献４で開示された方法では、周囲温度を一定に制御する恒温制御部が必要となる問題がある。   However, the configuration of the microwave densitometer disclosed in Patent Document 3 has a problem that it is necessary to newly provide another receiving antenna. Further, the method disclosed in Patent Document 4 has a problem that a constant temperature control unit for controlling the ambient temperature to be constant is required.

本発明は、このような従来の問題点を解決するためになされたもので、新たな受信アンテナや、送受信アンテナ周辺部を覆う恒温制御部を設けることなく、液温の急変があっても測定誤差を軽減することが可能なマイクロ波濃度計、及びその液温補正方法を提供することを目的とする。   The present invention has been made to solve such a conventional problem, and it is possible to measure even if there is a sudden change in liquid temperature without providing a new receiving antenna or a constant temperature control unit covering the periphery of the transmitting / receiving antenna. An object of the present invention is to provide a microwave densitometer capable of reducing errors and a liquid temperature correction method thereof.

上記目的を達成するために、本発明のマイクロ波式濃度計は、被測定物質を含む被測定液体の流れる配管又は前記被測定液体を収納した容器を介して対向配置されたマイクロ波の送受信アンテナと、この送信アンテナから発射され前記被測定液体を通過し前記受信アンテナにて受信されたマイクロ波の位相遅れθ２と、予め前記被測定物質を含まない液体を用いて測定しておいた位相遅れθ１との位相差Δθ（Δθ＝θ２−θ１）を求めることにより前記被測定液体の濃度を測定するマイクロ波式の濃度計であって、前記被測定液体の液温ｔ２を測定し、予め測定しておいた被測定物質を含まない前記液体の液温ｔ１との温度差Δｔ（＝ｔ２−ｔ１）に基づき前記位相差Δθを補正する液温補正値を求め、さらに、前記送受信アンテナのいずれかのアンテナ温度ｔａを測定し、前記液温ｔ２と当該アンテナ温度ｔａとの温度差を求めて前記位相差を補正する液温・アンテナ温度差補正値を求め、前記液温補正値と前記液温・アンテナ温度差補正値とから前記位相差Δθを補正し、前記被測定液体の濃度を求める温度補正演算部を供えたことを特徴とする。   In order to achieve the above object, a microwave concentration meter according to the present invention includes a microwave transmitting / receiving antenna disposed opposite to each other through a pipe through which a liquid to be measured containing a substance to be measured flows or a container containing the liquid to be measured. And the phase lag θ2 of the microwave emitted from the transmitting antenna, passing through the liquid to be measured and received by the receiving antenna, and the phase lag measured in advance using the liquid not containing the substance to be measured A microwave type concentration meter that measures the concentration of the liquid to be measured by obtaining a phase difference Δθ (Δθ = θ2−θ1) with respect to θ1, and measures the liquid temperature t2 of the liquid to be measured in advance. A liquid temperature correction value for correcting the phase difference Δθ is obtained based on a temperature difference Δt (= t2−t1) with respect to the liquid temperature t1 of the liquid that does not include the measured substance, and Kana The antenna temperature ta is measured, the temperature difference between the liquid temperature t2 and the antenna temperature ta is determined to determine the liquid temperature / antenna temperature difference correction value for correcting the phase difference, and the liquid temperature correction value and the liquid temperature / A temperature correction calculation unit is provided that corrects the phase difference Δθ from an antenna temperature difference correction value and obtains the concentration of the liquid to be measured.

また、上記目的を達成するために、本発明のマイクロ波式濃度計の液温補正方法は、被測定物質を含む被測定液体の流れる配管又は前記液体を収納した容器を介して対向配置されたマイクロ波の送受信アンテナと、この送信アンテナから発射され前記被測定液体を通過し前記受信アンテナにて受信されたマイクロ波の位相遅れθ２と、予め前記被測定物質を含まない液体を用いて測定しておいた位相遅れθ１との位相差Δθ（Δθ＝θ２−θ１）を求めることにより前記被測定液体の濃度を測定するマイクロ波式の濃度計において、前記被測定液体の液温が急変した場合の液温補正方法であって、前記被測定液体の液温ｔ２を測定し、予め測定しておいた被測定物質を含まない前記液体の液温ｔ１との温度差Δｔ（＝ｔ２−ｔ１）に基づき前記位相差Δθを補正する液温補正値を求める第１のステップと、前記送受信アンテナのいずれかのアンテナ温度ｔａを測定し、前記液温ｔ２と当該アンテナ温度ｔａとの温度差を求めて前記位相差を補正する液温・アンテナ温度差補正値を求める第２のステップと、前記液温補正値と前記液温・アンテナ温度差補正値とから前記位相差Δθを補正し、前記被測定液体の濃度を求める第３のステップとから成る。   Further, in order to achieve the above object, the method for correcting the liquid temperature of the microwave concentration meter of the present invention is disposed so as to face each other through a pipe through which a liquid to be measured containing a substance to be measured flows or a container containing the liquid. Measurement is performed using a microwave transmission / reception antenna, a microwave phase delay θ2 emitted from the transmission antenna, passed through the liquid to be measured and received by the reception antenna, and a liquid not containing the substance to be measured in advance. In the microwave type concentration meter that measures the concentration of the liquid to be measured by calculating the phase difference Δθ (Δθ = θ2−θ1) with respect to the phase delay θ1, the liquid temperature of the liquid to be measured changes suddenly. In this liquid temperature correction method, the liquid temperature t2 of the liquid to be measured is measured, and the temperature difference Δt (= t2−t1) from the liquid temperature t1 of the liquid not including the substance to be measured previously measured. Based on said phase A first step of obtaining a liquid temperature correction value for correcting Δθ, and measuring an antenna temperature ta of any one of the transmission / reception antennas, obtaining a temperature difference between the liquid temperature t2 and the antenna temperature ta, and calculating the phase difference. The second step of obtaining a correction value for the liquid temperature / antenna temperature difference to be corrected, the phase difference Δθ is corrected from the liquid temperature correction value and the liquid temperature / antenna temperature difference correction value, and the concentration of the liquid to be measured is determined. And a third step to obtain.

以上説明したように、本発明によれば、新たな受信アンテナや、送受信アンテナ周辺部を覆う恒温制御部を設けることなく、液温の急変があっても測定誤差を軽減することが可能なマイクロ波濃度計、及びその液温補正方法を提供することができる。   As described above, according to the present invention, the measurement error can be reduced even if there is a sudden change in the liquid temperature without providing a new receiving antenna or a constant temperature control unit that covers the periphery of the transmitting / receiving antenna. A wave densitometer and a liquid temperature correction method thereof can be provided.

図１乃至図５を参照して説明する。図１はマイクロ波式濃度計の構成図である。図１に示す構成が、特許文献1等に示される従来の構成と異なる点は、送信アンテナ２に自身の温度を測定するアンテナ温度センサ６を設け、さらに温度補正演算部１４に、液温・アンテナ温度差補正テーブル１４ｂを備えるようにした点にある。   This will be described with reference to FIGS. FIG. 1 is a configuration diagram of a microwave densitometer. The configuration shown in FIG. 1 is different from the conventional configuration shown in Patent Document 1 and the like in that the antenna temperature sensor 6 for measuring its own temperature is provided in the transmission antenna 2, and the liquid temperature / The antenna temperature difference correction table 14b is provided.

本実施例によるマイクロ波式濃度計の構成は、被測定液体を流す検出部１０と、検出部１０からの信号を受信して被測定液体の濃度を求める信号処理部２０とから成る。   The configuration of the microwave concentration meter according to the present embodiment includes a detection unit 10 for flowing a liquid to be measured, and a signal processing unit 20 that receives a signal from the detection unit 10 and obtains the concentration of the liquid to be measured.

検出部１０は、金属管で成形される配管３の管外壁側から被測定液体に接液して設けられるマイクロ波の送信アンテナ４及び受信アンテナ５と、これらの送信アンテナ４及び受信アンテナ５は配管３を介して、配管３の管軸と直交する方向の配管管壁面で、互いに対向位置に配置されている。   The detection unit 10 includes a microwave transmission antenna 4 and a reception antenna 5 provided in contact with the liquid to be measured from the pipe outer wall side of the pipe 3 formed of a metal pipe, and the transmission antenna 4 and the reception antenna 5. Via the pipe 3, the pipe pipe wall surfaces in a direction orthogonal to the pipe axis of the pipe 3 are arranged at positions facing each other.

また、送信アンテナ４には、自身の温度を計測するアンテナ温度センサ６が設けられ、被測定液体の液温を測定する液温温度センサ７が、配管３の管壁を貫通して設けられる。   The transmitting antenna 4 is provided with an antenna temperature sensor 6 that measures its own temperature, and a liquid temperature sensor 7 that measures the liquid temperature of the liquid to be measured is provided so as to penetrate the wall of the pipe 3.

送受信アンテナ４、５は、設置される外気温が異なる場合、後述する理由により、夫々の温度が一様となる様に外気と断熱されるように断熱材等で覆うようにすることが望ましい。   When the outside air temperatures to be installed are different, the transmission / reception antennas 4 and 5 are desirably covered with a heat insulating material or the like so as to be insulated from the outside air so that the respective temperatures become uniform for reasons described later.

また、アンテナ温度センサ６と液温温度センサ７とは、同じタイプの温度センサとしておくことが望ましい。   The antenna temperature sensor 6 and the liquid temperature sensor 7 are preferably the same type of temperature sensor.

信号処理部２０は、マイクロ波発信器１と、当該マイクロ波発信器1から送信されるマイクロ波は信号を２系統に分岐ずるパワースプリッタ２と、パワースプリッタ２から送信されたマイクロ波信号を送受信アンテナ４、被測定液体、及び受信アンテナ５を介して送信される一方の測定系経路のマイクロ波信号と、他方のパワースプリッタ２から直接出力された基準系経路のマイクロ波信号との位相差を測定する位相差測定部１１と、当該位相差測定部１１の出力から液温、及び液温とアンテナ温度との温度差による位相差の補正演算を行なう温度補正演算部１４と、温度補正された位相差と濃度との関係を求める濃度演算部１５とから成る。   The signal processing unit 20 transmits / receives a microwave transmitter 1, a microwave transmitted from the microwave transmitter 1, a power splitter 2 that branches the signal into two systems, and a microwave signal transmitted from the power splitter 2. The phase difference between the microwave signal of one measurement system path transmitted via the antenna 4, the liquid to be measured, and the receiving antenna 5 and the microwave signal of the reference system path directly output from the other power splitter 2 is calculated. The phase difference measuring unit 11 to be measured, the temperature correction calculating unit 14 for performing the correction calculation of the liquid temperature from the output of the phase difference measuring unit 11, and the phase difference due to the temperature difference between the liquid temperature and the antenna temperature, and the temperature correction It comprises a density calculator 15 for obtaining the relationship between the phase difference and the density.

また、アンテナ温度センサ６及び液温温度センサ７からの信号を受信して、温度補正演算部１４に温度信号を出力する変換器１２及び変換器１３を備える。   In addition, a converter 12 and a converter 13 that receive signals from the antenna temperature sensor 6 and the liquid temperature sensor 7 and output a temperature signal to the temperature correction calculation unit 14 are provided.

また、このように構成された信号処理部２０は、測定系路と基準経路の同じ温度環境に維持するため、検出部１０と一体の構造としておくことが望ましい。   Further, it is desirable that the signal processing unit 20 configured in this way has a structure integrated with the detection unit 10 in order to maintain the same temperature environment of the measurement system path and the reference path.

次に、送信アンテナの詳細構造について、図２を参照して説明する。図２（ａ）は、送信アンテナ４の断面図で、配管３の管軸と直交する方向から見たものである。   Next, the detailed structure of the transmission antenna will be described with reference to FIG. FIG. 2A is a cross-sectional view of the transmission antenna 4 as viewed from a direction orthogonal to the tube axis of the pipe 3.

アンテナ温度センサ６は、送受信アンテナ４、５の温度が一様と見なせる状態を確保して、いずれか一方に設ける。送信アンテナ４と受信アンテナ５とが異なる点は、アンテナ温度センサ６を備えているか否かにあるので、以下、送信アンテナ５について説明し、受信アンテナ５の説明を省略する。   The antenna temperature sensor 6 is provided on either one of the antennas while ensuring that the temperature of the transmitting and receiving antennas 4 and 5 can be regarded as uniform. Since the difference between the transmission antenna 4 and the reception antenna 5 is whether or not the antenna temperature sensor 6 is provided, the transmission antenna 5 will be described below and the description of the reception antenna 5 will be omitted.

送信アンテナ４は、金属管等で成形される配管３の開口部で被測定液体に接液するように外壁側から挿入して配管３に固定される合成樹脂部材４ａと、セラミックス等の絶縁体の板に設けられ、同軸ケーブル４ｄからマイクロ波信号を供給されて、マイクロ波信号を配管３内の方向に合成樹脂部材４ａを介して送信するアンテナ４ｃと、このアンテナ４ｃから送信されるマイクロ波信号を送信する開口部を備え、配管３の開口部の外壁位置に固定されるアンテナ固定部材４ｂ１と、アンテナ固定部４ｂ１上にアンテナ４ｃ固定するアンテナ固定部材４ｂ２とから成る。   The transmitting antenna 4 includes a synthetic resin member 4a that is inserted from the outer wall side and fixed to the pipe 3 so as to be in contact with the liquid to be measured at the opening of the pipe 3 formed of a metal pipe or the like, and an insulator such as ceramics The antenna 4c is provided on the plate, is supplied with a microwave signal from the coaxial cable 4d, and transmits the microwave signal in the direction of the pipe 3 through the synthetic resin member 4a, and the microwave transmitted from the antenna 4c. The antenna fixing member 4b1 is provided with an opening for transmitting a signal and is fixed to an outer wall position of the opening of the pipe 3, and an antenna fixing member 4b2 for fixing the antenna 4c on the antenna fixing portion 4b1.

そして、合成樹脂部材４ａとアンテナ４ｃとが対面する面間は、合成樹脂部材４ａ及びアンテナ４ｃが、周囲温度の変化で変形した場合でもアンテナ４ｃが機械的なストレスを受けないように所定の間隙を備えるように、予め当該アンテナ固定部材４ａ、または前記合成樹脂部材４ｂ１を所定の厚さで成形しておく。   A gap between the surfaces of the synthetic resin member 4a and the antenna 4c facing each other is such that the antenna 4c is not subjected to mechanical stress even when the synthetic resin member 4a and the antenna 4c are deformed due to a change in ambient temperature. The antenna fixing member 4a or the synthetic resin member 4b1 is molded in advance with a predetermined thickness.

さらに、アンテナ４ｃは、温度変化による変形以外に、合成樹脂部材４ａが被測定流体の圧力を受けて変形する恐れがないような隙間としておく。   Further, the antenna 4c is provided with a gap that prevents the synthetic resin member 4a from being deformed due to the pressure of the fluid to be measured, other than deformation due to temperature change.

また、アンテナ固定部材４ｂ２にはメネジ部Ａを備え、アンテナ温度センサ６は、測温抵抗体６ｂとその保護管６ａとからなり、該保護管６ａの先端部にはメネジ部Ａに嵌合するオネジ部を備え、該オネジ部の内部に測温抵抗体６ｂの感温部を密着させ、このメネジ部Ａに保護管６ａのオネジ部をねじ込みして固定する。   The antenna fixing member 4b2 includes a female screw portion A. The antenna temperature sensor 6 includes a resistance temperature detector 6b and a protective tube 6a thereof, and the female screw portion A is fitted to the tip of the protective tube 6a. A male screw part is provided, and the temperature sensing part of the resistance temperature detector 6b is brought into close contact with the male screw part, and the male screw part of the protective tube 6a is screwed into the female screw part A and fixed.

また、配管３内の被測定液体の液温は、配管３の管壁に貫通して設けられる挿入型の液温度センサ７で検出する。   Further, the liquid temperature of the liquid to be measured in the pipe 3 is detected by an insertion type liquid temperature sensor 7 provided penetrating the pipe wall of the pipe 3.

以上のような構成とするので、被測定液体の液温は、配管３、アンテナ固定部材４ｂ１及び４ｂ２とから成る熱伝導の良い金属を介してアンテナ４ｃに効率よく伝熱される。また、測温抵抗体６ｂは、アンテナ４ｃと密着して設けられるので、アンテナ４ｃ自身の温度が精度良く素早く検出できる。   With the configuration as described above, the liquid temperature of the liquid to be measured is efficiently transferred to the antenna 4c through the metal having good heat conductivity including the pipe 3 and the antenna fixing members 4b1 and 4b2. Moreover, since the resistance temperature detector 6b is provided in close contact with the antenna 4c, the temperature of the antenna 4c itself can be detected quickly with high accuracy.

次に、このように構成されたマイクロ波式濃度計の信号処理部２０の動作について説明する。先ず、従来の液温補正テーブル１４ａ及び本発明による液温・アンテナ温度差補正テーブル１４ｂの生成方法について説明する。   Next, the operation of the signal processing unit 20 of the microwave densitometer configured as described above will be described. First, a method for generating the conventional liquid temperature correction table 14a and the liquid temperature / antenna temperature difference correction table 14b according to the present invention will be described.

液温補正テーブル１４ａは、送信アンテナから送信されて配管３内の被測定用液体を伝搬して前受信アンテナにて受信されたマイクロ波の位相遅れθ２を測定し、また、予め配管３内に基準用液体(例えば、濃度０％見なせる水道水)を充填して測定用液体と同じ条件で測定したときのマイクロ波の位相遅れとを比較し、その位相差Δθ＝（θ２−θ１）を測定し、この位相差Δθを、測定用液体の液温ｔ２と基準用液体の液温ｔ１との温度差Δｔ（＝ｔ２−ｔ１）に基づいて補正し、位相差Δθｔと温度差Δｔの関係を一次式で近似し、この一次の傾斜角αをテーブル化しておく。   The liquid temperature correction table 14a measures the phase delay θ2 of the microwave transmitted from the transmitting antenna and propagating through the liquid to be measured in the pipe 3 and received by the previous receiving antenna. Comparing the phase delay of the microwave when filling the reference liquid (for example, tap water with a concentration of 0%) and measuring under the same conditions as the measurement liquid, and measuring the phase difference Δθ = (θ2−θ1) The phase difference Δθ is corrected based on the temperature difference Δt (= t2−t1) between the liquid temperature t2 of the measurement liquid and the liquid temperature t1 of the reference liquid, and the relationship between the phase difference Δθt and the temperature difference Δt is corrected. Approximation is performed using a linear expression, and the primary inclination angle α is tabulated.

この時の濃度Ｘは、一般的に、この液温補正テーブルを参照して、下記検量線で求められる。   The concentration X at this time is generally obtained by the following calibration curve with reference to this liquid temperature correction table.

Ｘ＝ａ×（Δθ（＝θ２-θ１）−α×（ｔ２−ｔ１））＋ｂ
ここで、ａ及びｂは、一次式で示される検量線の傾きａ及び切片ｂで、被測定液体の濃度や液温差（ｔ２−ｔ１）が大きい場合、零点の補正のみで不十分である場合の補正値である。 X = a × (Δθ (= θ2−θ1) −α × (t2−t1)) + b
Here, a and b are the slope a and the intercept b of the calibration curve expressed by the linear expression, and when the concentration of the liquid to be measured and the liquid temperature difference (t2-t1) are large, it is not sufficient only to correct the zero point. Is the correction value.

次に、液温・アンテナ温度差補正テーブル１４ｂの生成方法について図３及び図４を参照して説明する。図３は、液温ｔ２を６５℃から１７℃に急変させたときの液温補正テーブルのみを備えたマイクロ波式濃度計の測定誤差εｘと、アンテナ温度ｔａの応答を図示したものである。   Next, a method for generating the liquid temperature / antenna temperature difference correction table 14b will be described with reference to FIGS. FIG. 3 shows the response of the measurement error εx of the microwave densitometer having only the liquid temperature correction table and the antenna temperature ta when the liquid temperature t2 is suddenly changed from 65 ° C. to 17 ° C.

この実験に用いたマイクロ波式濃度計の場合、液温温度センサ７の出力がほぼ一定の１７℃に安定する時間(約７分)を経過した後の濃度の測定誤差εｘ（％）は、液温補正が除かれた後の誤差要因に因るもの見なせる。   In the case of the microwave densitometer used in this experiment, the concentration measurement error εx (%) after the time (about 7 minutes) during which the output of the liquid temperature sensor 7 is stabilized at a substantially constant 17 ° C. has passed. This can be attributed to the error factor after the liquid temperature correction is removed.

この測定誤差εｘは、液温ｔ２と送受信アンテナ温度ｔａとの温度差Δｔａが減少すれば減少し、温度差Δｔａが無ければ０％と見なせる。そこで、図４に示すように、この温度差Δｔａと測定誤差εｘとの関係を一次式で近似して、その傾きβを求め、この傾きβ（＝−０．８４９）をテーブル化して、液温・アンテナ温度差補正テーブル１４ｂとする。   This measurement error εx decreases when the temperature difference Δta between the liquid temperature t2 and the transmission / reception antenna temperature ta decreases, and can be regarded as 0% if there is no temperature difference Δta. Therefore, as shown in FIG. 4, the relationship between the temperature difference Δta and the measurement error εx is approximated by a linear expression to obtain the slope β, and this slope β (= −0.849) is tabulated to form a liquid. The temperature / antenna temperature difference correction table 14b is used.

このようにして求めた液温・アンテナ温度差補正テーブル１４ｂを使用して、図３の測定値を補正すると、図５に示すように液温補正後の測定誤差がεｘは、測定誤差εｘｃに示すように補正される。   When the measured value of FIG. 3 is corrected using the liquid temperature / antenna temperature difference correction table 14b thus obtained, the measurement error εx after the liquid temperature correction becomes the measurement error εxc as shown in FIG. Corrected as shown.

即ち、このような温度補正演算部１４によれば、濃度の測定誤差は、下記検量線で求められる。   That is, according to such a temperature correction calculation unit 14, the concentration measurement error can be obtained by the following calibration curve.

Ｘ＝ａ×（Δθ−α×（ｔ２−ｔ１）−β（ｔ２−ｔａ））＋ｂ
ここで、ａ及びｂは、夫々、検量線の傾き及び切片の値である。また、液温とアンテナ温度差を補正する傾きβは、配管３の口径、肉厚等の形状及び材質により、また、測定する被測定液体の液温温度範囲によって変わるので、配管３を含む検出部１０と被測定液体の測定する液温範囲毎に液温・アンテナ温度差補正テーブル１４ｂを作成しておく。 X = a × (Δθ−α × (t2−t1) −β (t2−ta)) + b
Here, a and b are values of the slope and intercept of the calibration curve, respectively. In addition, since the inclination β for correcting the difference between the liquid temperature and the antenna temperature varies depending on the shape and material of the diameter, thickness, etc. of the pipe 3 and the liquid temperature range of the liquid to be measured, detection including the pipe 3 The liquid temperature / antenna temperature difference correction table 14b is created for each liquid temperature range measured by the unit 10 and the liquid to be measured.

以上述べたように、本実施例に拠れば、液温とアンテナとの温度差による測定誤差を予め記憶しているので、測定する被測定液体の液温が急変して、測定誤差を液温温度センサ、アンテナ温度センサの応答速度で素早く補正することが出来る。   As described above, according to this embodiment, since the measurement error due to the temperature difference between the liquid temperature and the antenna is stored in advance, the liquid temperature of the liquid to be measured changes suddenly, and the measurement error is Correction can be made quickly with the response speed of the temperature sensor and antenna temperature sensor.

本発明は、上述したような実施例に何ら限定されるものではなく、アンテナ温度センサ及びその固定方法は、送信アンテナまたは受信アンテナの温度を近接して測定できるものであれば良く、その構造により本発明の主旨を逸脱しない範囲内で種々変形して実施することができる。   The present invention is not limited to the above-described embodiments, and the antenna temperature sensor and its fixing method may be any as long as the temperature of the transmitting antenna or the receiving antenna can be measured in close proximity. Various modifications can be made without departing from the spirit of the present invention.

本発明の構成図。The block diagram of this invention. 送信アンテナ、または、受信アンテナの構造図。The structure diagram of a transmitting antenna or a receiving antenna. 従来の液温補正時の測定誤差。Measurement error at the time of conventional liquid temperature correction. 本発明の液温・アンテナ温度差補正（β）を求める例。The example which calculates | requires liquid temperature and antenna temperature difference correction | amendment ((beta)) of this invention. 本発明の液温及び液温・アンテナ温度差補正時の測定誤差。Measurement error at the time of liquid temperature and liquid temperature / antenna temperature difference correction of the present invention.

符号の説明Explanation of symbols

１ マイクロ波発信器
２ パワースプリッタ
３ 配管
４ 送信アンテナ
４ａ 合成樹脂部材
４ｂ１、４ｂ２ アンテナ固定部材
４ｂ２ 温度センサ取り付けネジ穴
４ｃ アンテナ
４ｄ 同軸ケーブル
５ 受信アンテナ
６ アンテナ温度センサ
６ａ 保護管
６ｂ 測温抵抗体
７ 液温温度センサ
１０ 検出部
１２、１３ 変換器
１４ 温度補正演算部
１５ 濃度演算部
２０ 濃度演算部 DESCRIPTION OF SYMBOLS 1 Microwave transmitter 2 Power splitter 3 Piping 4 Transmitting antenna 4a Synthetic resin member 4b1, 4b2 Antenna fixing member 4b2 Temperature sensor attachment screw hole 4c Antenna 4d Coaxial cable 5 Receiving antenna 6 Antenna temperature sensor 6a Protective tube 6b Resistance temperature detector 7 Liquid temperature sensor 10 Detection unit 12, 13 Converter 14 Temperature correction calculation unit 15 Concentration calculation unit 20 Concentration calculation unit

Claims (5)

被測定物質を含む被測定液体の流れる配管又は前記被測定液体を収納した容器を介して対向配置されたマイクロ波の送受信アンテナと、この送信アンテナから発射され前記被測定液体を通過し前記受信アンテナにて受信されたマイクロ波の位相遅れθ２と、予め前記被測定物質を含まない液体を用いて測定しておいた位相遅れθ１との位相差Δθ（Δθ＝θ２−θ１）を求めることにより前記被測定液体の濃度を測定するマイクロ波式の濃度計であって、
前記被測定液体の液温ｔ２を測定し、予め測定しておいた被測定物質を含まない前記液体の液温ｔ１との温度差Δｔ（ｔ２−ｔ１）に基づき前記位相差Δθを補正する液温補正値を求め、さらに、前記送受信アンテナのいずれかのアンテナ温度ｔａを測定し、前記液温ｔ２と当該アンテナ温度ｔａとの温度差を求めて前記位相差を補正する液温・アンテナ温度差補正値を求め、前記液温補正値と前記液温・アンテナ温度差補正値とから前記位相差Δθを補正し、前記被測定液体の濃度を求める温度補正演算部を供えたことを特徴とするマイクロ波式濃度計。 A microwave transmission / reception antenna disposed oppositely through a pipe through which the liquid to be measured flows containing the substance to be measured or a container containing the liquid to be measured, and the receiving antenna emitted from the transmission antenna and passing through the liquid to be measured Is obtained by obtaining a phase difference Δθ (Δθ = θ2−θ1) between the phase delay θ2 of the microwave received at 1 and the phase delay θ1 measured in advance using a liquid not containing the substance to be measured. A microwave type concentration meter for measuring the concentration of a liquid to be measured,
A liquid that measures the liquid temperature t2 of the liquid to be measured and corrects the phase difference Δθ based on a temperature difference Δt (t2−t1) with respect to the liquid temperature t1 of the liquid that does not include the substance to be measured. Liquid temperature / antenna temperature difference for obtaining a temperature correction value, further measuring the antenna temperature ta of any of the transmission / reception antennas, and obtaining the temperature difference between the liquid temperature t2 and the antenna temperature ta to correct the phase difference A correction value is obtained, and a temperature correction calculation unit is provided for correcting the phase difference Δθ from the liquid temperature correction value and the liquid temperature / antenna temperature difference correction value to obtain the concentration of the liquid to be measured. Microwave densitometer. 前記配管は金属で成形され、該配管の管軸と直交する管壁面の対向する位置には、前記送受信アンテナを取り付ける開口部を備え、
前記送受信アンテナは、セラミックス等の絶縁体の板に設けられるアンテナと、前記配管の前記開口部で前記被測定液体に接液するように外壁側から挿入して当該配管に固定される合成樹脂部材と、当該開口部の外壁に固定され、該外壁側から前記アンテナを固定する金属から成るアンテナ固定部材とから成り、
当該アンテナ固定部材または前記合成樹脂部材は、前記合成樹脂部材と前記アンテナが周囲温度の変化による変形と前記合成樹脂部材が前記被測定流体の圧力による変形とが同時に、または、夫々が個別に発生しても、当該アンテナと当該合成樹脂部材とが接触しない隙間を確保できるように夫々の厚さを成形し、
いずれかの前記アンテナ固定部材には、当該アンテナ固定部材に密着して設けられるアンテナ温度センサを備えた請求項１に記載のマイクロ波式濃度計。 The pipe is formed of metal, and has an opening for attaching the transmitting / receiving antenna at a position facing the pipe wall surface perpendicular to the pipe axis of the pipe,
The transmission / reception antenna includes an antenna provided on an insulating plate such as ceramics, and a synthetic resin member that is inserted from the outer wall side and fixed to the pipe so as to be in contact with the liquid to be measured at the opening of the pipe And an antenna fixing member made of a metal fixed to the outer wall of the opening and fixing the antenna from the outer wall side,
In the antenna fixing member or the synthetic resin member, the synthetic resin member and the antenna are deformed due to a change in ambient temperature and the synthetic resin member is deformed due to the pressure of the fluid to be measured simultaneously or individually. Even then, the respective thicknesses are molded so as to ensure a gap where the antenna and the synthetic resin member do not contact,
The microwave densitometer according to claim 1, wherein any one of the antenna fixing members includes an antenna temperature sensor provided in close contact with the antenna fixing member. 前記アンテナ固定部材にはメネジ部を備え、前記アンテナ温度センサは、測温抵抗体とその保護管とからなり、該保護管の先端部に前記メネジ部に嵌合するオネジ部を備え、前記オネジ部の内部に前記測温抵抗体の感温部を密着させ、前記メネジ部に前記保護管６ａのオネジ部をねじ込みしたことを特徴とする請求項２に記載のマイクロ波式濃度計。   The antenna fixing member includes a female screw portion, and the antenna temperature sensor includes a resistance temperature detector and its protective tube, and includes a male screw portion that fits into the female screw portion at a distal end portion of the protective tube, The microwave densitometer according to claim 2, wherein the temperature sensing part of the resistance temperature detector is brought into close contact with the inside of the part, and the male thread part of the protective tube 6a is screwed into the female thread part. 前記温度補正演算部は、前記被測定液体を予め定められる第1の液温として、予め求められた前記液温補正値を使用して液温補正演算を実行し、
その後、前記被測定液体を第２の液温に急変させた時の濃度の測定誤差と、当該被測定液体の液温と前記送受信アンテナの温度との温度差との応答関係を一次式で直線近似して当該一次式の傾きを求めて液温・アンテナ温度差補正値としてテーブル化したことを特徴とする請求項１に記載のマイクロ波式濃度計。 The temperature correction calculation unit performs a liquid temperature correction calculation using the liquid temperature correction value determined in advance as the first liquid temperature to be measured in advance,
Thereafter, a linear relationship between the measurement error of the concentration when the liquid to be measured is suddenly changed to the second liquid temperature and the temperature difference between the liquid temperature of the liquid to be measured and the temperature of the transmitting / receiving antenna is a linear expression. The microwave densitometer according to claim 1, characterized in that the slope of the linear expression is approximated and tabulated as a liquid temperature / antenna temperature difference correction value. 被測定物質を含む被測定液体の流れる配管又は前記液体を収納した容器を介して対向配置されたマイクロ波の送受信アンテナと、この送信アンテナから発射され前記被測定液体を通過し前記受信アンテナにて受信されたマイクロ波の位相遅れθ２と、予め前記被測定物質を含まない液体を用いて測定しておいた位相遅れθ１との位相差Δθ（Δθ＝θ２−θ１）を求めることにより前記被測定液体の濃度を測定するマイクロ波式の濃度計において、前記被測定液体の液温が急変した場合の液温補正方法であって、
前記被測定液体の液温ｔ２を測定し、予め測定しておいた被測定物質を含まない前記液体の液温ｔ１との温度差Δｔ（＝ｔ２−ｔ１）に基づき前記位相差Δθを補正する液温補正値を求める第１のステップと、
前記送受信アンテナのいずれかのアンテナ温度ｔａを測定し、前記液温ｔ２と当該アンテナ温度ｔａとの温度差を求めて前記位相差を補正する液温・アンテナ温度差補正値を求める第２のステップと、
前記液温補正値と前記液温・アンテナ温度差補正値とから前記位相差Δθを補正し、前記被測定液体の濃度を求める第３のステップとから成るマイクロ波式濃度の液温補正方法。 A microwave transmission / reception antenna disposed oppositely through a pipe through which the liquid to be measured flows containing the substance to be measured or a container containing the liquid, and the reception antenna that is emitted from the transmission antenna and passes through the liquid to be measured. The phase to be measured is obtained by obtaining a phase difference Δθ (Δθ = θ2−θ1) between the phase delay θ2 of the received microwave and the phase delay θ1 measured in advance using a liquid not containing the substance to be measured. In the microwave type concentration meter for measuring the concentration of the liquid, a liquid temperature correction method when the liquid temperature of the liquid to be measured changes suddenly,
The liquid temperature t2 of the liquid to be measured is measured, and the phase difference Δθ is corrected based on a temperature difference Δt (= t2−t1) with respect to the liquid temperature t1 of the liquid that does not contain the substance to be measured. A first step for obtaining a liquid temperature correction value;
A second step of obtaining a liquid temperature / antenna temperature difference correction value by measuring the antenna temperature ta of any of the transmission / reception antennas, obtaining a temperature difference between the liquid temperature t2 and the antenna temperature ta, and correcting the phase difference. When,
A microwave concentration liquid temperature correction method comprising a third step of correcting the phase difference Δθ from the liquid temperature correction value and the liquid temperature / antenna temperature difference correction value to obtain the concentration of the liquid to be measured.
JP2008160526A 2008-06-19 2008-06-19 Microwave-type densitometer and liquid temperature correcting method thereof Pending JP2010002268A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012026978A (en) * 2010-07-27 2012-02-09 Toshiba Corp Microwave densitometer
JP2014048048A (en) * 2012-08-29 2014-03-17 Toshiba Corp Microwave densitometer
CN105723196A (en) * 2013-11-07 2016-06-29 滤波器感知技术有限公司 Advanced radio frequency sensing probe

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012026978A (en) * 2010-07-27 2012-02-09 Toshiba Corp Microwave densitometer
JP2014048048A (en) * 2012-08-29 2014-03-17 Toshiba Corp Microwave densitometer
CN105723196A (en) * 2013-11-07 2016-06-29 滤波器感知技术有限公司 Advanced radio frequency sensing probe
JP2016538540A (en) * 2013-11-07 2016-12-08 フィルター・センシング・テクノロジーズ・インコーポレイテッドＦｉｌｔｅｒ Ｓｅｎｓｉｎｇ Ｔｅｃｈｎｏｌｏｇｉｅｓ，Ｉｎｃ． Advanced radio frequency sensing probe
US10890603B2 (en) 2013-11-07 2021-01-12 Cts Corporation Advanced radio frequency sensing probe

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