JP6624610B2 - Temperature sensor and temperature measurement method - Google Patents

Description

  The present invention relates to a temperature sensor and a temperature measuring method.

  As a sensor for obtaining time-series information of the abundance of liquid and gas in a gas-liquid two-phase flow at multiple points in a cross section of a fluid flowing through a pipeline, a wire mesh sensor (Wire- Mesh Sensor (WMS) is known. Such a wire mesh sensor includes a first wire electrode and a second wire electrode which cross each other at a predetermined distance in an axial direction of a conduit through which a fluid flows, and are arranged in a square lattice in a cross section of the conduit. And an impedance measurement sensor using the first wire electrode as an excitation electrode and the second wire electrode as a measurement electrode. In the wire mesh sensor, the wires are close to each other but not in contact. Hereinafter, a portion where the wires are close to each other is referred to as an intersection for convenience.

  In the impedance measurement sensor having the wire mesh sensor, the excitation pulse is applied to the input line formed by the first wire electrode by each switch in order from the first row. Here, the excitation pulse is supplied from a power supply via a changeover switch. With the application of the excitation pulse, the impedance at each intersection of the first wire electrode and the second wire electrode changes according to the state of the fluid that short-circuits each intersection. As a result, in the impedance measurement sensor, a measurement signal reflecting the impedance at each intersection is output to an output line formed by the second wire electrode for each row. Then, by processing the output measurement signal in the arithmetic processing unit, the abundance of a desired substance, such as a gas-liquid ratio in a gas-liquid two-phase flow, at each intersection, can be measured by calculation.

  By the way, in recent years, measurement sensors and measurement systems to which the above wire mesh sensors are applied have been developed. Examples of such applications include, for example, a grid sensor (see Patent Document 1) for measuring the conductivity distribution in a flowing medium for the purpose of measuring the void fraction of a gas-liquid two-phase flow, and a method for measuring the void ratio between a plurality of rod-shaped members. And an impedance measurement sensor (see Patent Documents 2 and 3) for measuring a medium (for example, a fluid) existing in the surroundings, or a tertiary that measures a three-dimensional velocity based on the impedance of a measurement target (for example, a bubble) in a flow path. An original speed measurement system (see Patent Documents 4 and 5) and the like.

Japanese Patent No. 4090077 Japanese Patent No. 5728764 Japanese Patent No. 5656219 JP 2013-3052 A JP 2013-246124 A

H. Pietruske. H. -M. Placer / Flow Measurement and Instrumentation 18 (2007) 87-94

  However, in recent years, further application of the above wire mesh sensor is expected.

  The present invention has been made in view of the above circumstances, and has as its object to provide a novel temperature sensor and a temperature measurement method to which a wire mesh sensor is applied.

  According to a first aspect of the present invention, there is provided a temperature sensor, comprising: a plurality of first wire electrodes arranged in a measurement object and spaced apart from each other; A wire mesh sensor comprising: an electrode; and a measurement electrode including a plurality of second wire electrodes disposed at intervals from each other and provided to intersect with the plurality of first wire electrodes. Input means for inputting an excitation signal to the wire electrode, detecting means for detecting a measurement signal reflecting the capacitance, inductance or conductance output from the second wire electrode, and detecting the capacitance, inductance or conductance. Arithmetic processing means for arithmetically processing a measurement signal to detect a temperature change of the measurement object.

  According to the first aspect of the present invention, it is possible to provide a temperature sensor based on a novel idea that a wire mesh sensor is provided in an object to be measured. That is, it is possible to provide a temperature sensor capable of easily and easily measuring a temperature change of a measurement object with time.

  A temperature sensor according to a second aspect of the present invention is characterized in that the object to be measured has a buffer added thereto.

  In the second aspect of the present invention, since the measurement object is a substance to which a buffer is added, it exhibits high conductivity with high stability against temperature change of the measurement object and improves S / N, A temperature sensor that can improve measurement accuracy can be provided.

  In a temperature sensor according to a third aspect of the present invention, the arithmetic processing means performs arithmetic processing on a measurement signal output from the second wire electrode to change a hydrogen ion concentration of the measurement object, It is characterized in that a change in ion concentration or a change in dissolved oxygen concentration is measured.

  In the third aspect of the present invention, in addition to temperature, pH, pOH and dissolved oxygen amount can be measured alone or in combination of a plurality of parameters, and a temperature sensor capable of performing measurement with higher flexibility Can be provided.

  A temperature sensor according to a fourth aspect of the present invention is characterized in that the first wire electrode and the second wire electrode are covered with an insulating material except for regions that intersect each other.

  In the fourth aspect of the present invention, since the wire electrodes are covered with the insulating material except for the region where they intersect with each other, noise of the temperature sensor is reduced and mutual interference is prevented, so that the measurement sensitivity is improved. It is possible to provide a temperature sensor that can be operated.

  In order to achieve the above object, a temperature measuring method according to a fifth aspect of the present invention is characterized in that an excitation electrode composed of a plurality of first wire electrodes arranged at intervals from each other, A wire mesh sensor having a plurality of first wire electrodes and a plurality of second wire electrodes and a measurement electrode formed of a plurality of second wire electrodes provided intersecting the first wire electrode; An excitation signal is input to the wire electrode, a capacitance signal output from the second wire electrode, a measurement signal reflecting the inductance or conductance is detected, and the capacitance, the inductance or the conductance is reflected. It is characterized by detecting a change in temperature of the measurement object, a change in hydrogen ion concentration, a change in hydroxide ion concentration, and / or a change in dissolved oxygen concentration.

  In the fifth aspect of the present invention, the temperature change and the hydrogen ion concentration of the measurement object are changed by the measurement signal reflecting the capacitance, inductance or conductance obtained by disposing the wire mesh sensor in the measurement object. And a temperature measurement method based on a novel idea of detecting a change in hydroxide ion concentration and / or a change in dissolved oxygen concentration. That is, it is possible to easily measure the temperature change and the like of the measurement target over time and easily, and to appropriately change the two-dimensional measurement distribution according to the form of the measurement target. It can be performed.

  The present invention can provide a novel temperature sensor and a temperature measurement method using a wire mesh sensor.

It is a schematic diagram which shows the measuring device which has a wire mesh sensor. It is a fragmentary sectional view of a measuring device which has a wire mesh sensor, (a) is a fragmentary sectional view in the direction of an axis of a tubular container, and (b) is a fragmentary sectional view of a diameter of a tubular container. It is the perspective view which showed the outline of the wire mesh sensor used in each Example. 4 is a graph showing the relationship between the temperature of boiling water and the measured potential in Example 1. 5 is a graph showing the change over time in the temperature of boiling water in each sensor of Example 1 and Comparative Example 1. 9 is a graph showing temperature sensitivity when 95 ° C. hot water is forcibly injected in Example 2. 9 is a graph showing temperature sensitivity when 95 ° C. hot water is injected by natural convection in Example 3. It is the result which showed the temperature sensitivity of the wire mesh sensor in Example 4, (a)-(d) is the measurement result of a matrix temperature change, (e)-(h) is (a)-(d). Each is a corresponding still image. It is the result which showed pH sensitivity of the wire mesh sensor in Example 5, (a)-(d) is the measurement result of the matrix pH change, (e)-(h) is (a)-(d). Each is a corresponding still image. It is the result which showed the dissolved oxygen sensitivity of the wire mesh sensor in Example 6, (a)-(d) is the measurement result of the change of the amount of dissolved oxygen of a matrix, (e)-(h) is (a)-( Still images corresponding to d). 14 is a graph showing the relationship between pH and measured potential in Example 7. 14 is a graph showing a relationship between a dissolved oxygen amount and a measured potential in Example 8. 19 is a graph showing the relationship between the pH and the conductivity of the aqueous sodium hydroxide solution in Example 9. 18 is a graph showing the relationship between the concentration of the aqueous sodium hydroxide solution and the conductivity in Example 10.

(1st Embodiment)
A configuration of a wire mesh sensor according to an embodiment of the present invention and a measurement device having the wire mesh sensor will be described with reference to FIGS.

  FIG. 1 is a schematic diagram showing a measuring device having a wire mesh sensor. FIG. 2 is a partial cross-sectional view of such a measuring device, in which (a) is a partial cross-sectional view in the axial direction of a tubular container provided with a wire mesh sensor in the measuring device, and (b) is a diameter of the tubular container. FIG.

  As shown in the figure, a measuring device having a wire mesh sensor (hereinafter, referred to as a “measuring device 1”) is provided in a tubular container 10 that holds and holds a measurement target 11 and in the tubular container 10, respectively. A plurality of wire mesh sensors 20, input means 30 for inputting an excitation signal PI to the wire mesh sensor 20, detection means 40 for detecting measurement signals PO1 to PO4 output from the wire mesh sensor 20, and detection means 40 An arithmetic processing means 50 for arithmetically processing the measured signals PO1 to PO4 and detecting a temperature change of the measurement object 11 is provided.

  In the measuring device 1, when the measuring object 11 is accommodated in the tubular container 10, a plurality of wire mesh sensors 20 are arranged in the measuring object 11, and the state is maintained. That is, the measuring device 1 is a temperature sensor based on a novel idea that the wire mesh sensor 20 is disposed in the measurement target 11. With this configuration, the measuring device 1 can easily and easily measure the temperature change of the measurement target 11 over time.

  The tubular container 10 accommodates the measurement target 11 on which the plurality of wire mesh sensors 20 are disposed, and holds the state. The tubular container 10 is only required to be able to maintain the housed state without damaging the plurality of wire mesh sensors 20 disposed in the measurement object 11, and the material, shape, size, etc. are not particularly limited, and the measurement object It can be appropriately changed according to the object 11 and the measuring device 1. In the present embodiment, although not shown, an opening for injecting the measurement object 11 is provided on the upper surface in the axial direction, and the cylindrical tubular container 10 in which the lower surface in the axial direction is closed is used.

  Here, the wire mesh sensor 20 can measure the temperature change of the measurement target 11 and measure the pH, pOH, dissolved oxygen (DO: Dissolved Oxygen), inductance, conductance, capacitance, and the like of the measurement target 11. It can also be measured. The measurement device 1 may measure these parameters independently, or may measure a plurality of parameters simultaneously. As described above, the measurement device 1 can appropriately select measurement parameters as needed, and can perform measurement with a high degree of freedom.

  In the present embodiment, in addition to a fluid such as a liquid, a gas, and a plasma, a solid that is a non-fluid can also be the measurement target 11. The measurement target 11 of the present embodiment is preferably a liquid. When the measurement object 11 is a solid and the temperature change is measured over time, the wire mesh sensor 20 is disposed in the measurement object 11 in advance. The tubular container 10 may not be used.

  The measurement object 11 may be used with a buffer added from the viewpoint of exhibiting a highly stable conductivity with respect to a temperature change and improving the S / N to improve the measurement accuracy. By adding a buffer to the measurement target 11, the rate of change of the sensor potential with respect to temperature can be increased. Thereby, the stability of the conductivity change with respect to the temperature change of the measuring object 11 can be improved. The amount of the buffer added may be about 1/1000 with respect to the total weight of the measurement object 11. Further, when the measurement object 11 is pure water, the conductivity of the pure water is extremely small, so that a small amount of dust (contamination) adversely affects the measurement sensitivity. However, by adding a buffer to the measurement object 11, the conductivity can be increased and the potential level can be increased to a level where the influence of contamination can be ignored. That is, since there is no need to increase the gain of the wire mesh sensor 20, only the signal amount (Signal) can be increased without changing the noise amount (Noise), and the S / N can be improved. Further, by adding a buffer to the measurement object 11, a highly stable conductivity with respect to a temperature change can be obtained, so that the calibration of the measurement device 1 is unnecessary. However, calibration may be performed as needed.

  The buffer applicable to the present embodiment is not particularly limited as long as it exhibits high conductivity with stability against temperature change and can improve S / N to improve measurement accuracy. When the substance 11 is a liquid, it is preferably added as a solution (buffer solution) containing a buffer. In the present embodiment, an acidic, alkaline, or near-neutral (pH 5 to pH 8) buffer solution can be used depending on the measurement target 11. For an acidic buffer, it is preferable to apply rhodamine B or the like as a buffer, and for an alkaline buffer, it is preferable to apply sodium hydroxide, uranine or the like as a buffer, and a buffer having a pH around neutrality is preferably used. It is preferable to use sodium sulfate, potassium sulfate, sodium nitrate, potassium nitrate or the like as a buffer. In this embodiment, these buffers can be dissolved in a solvent such as water and used as a buffer. The above-mentioned fluorescent dyes such as rhodamine B and uranine are suitable for buffers because they do not show a chemical reaction and have a high ion concentration. However, these fluorescent dyes are particularly suitable for particle image velocimetry (PIV: Particle). This is applicable when used in combination with visualization measurement such as Image Velocimetry.

  The wire mesh sensor 20 includes an excitation electrode 22 composed of four first wire electrodes (transmitter wires) 21a to 21d and a measurement electrode 24 composed of four second wire electrodes (receiver wires) 23a to 23d. It is configured. In the present embodiment, the number of each wire electrode is not limited to this, and can be appropriately changed according to the measurement accuracy of the wire mesh sensor 20 and the form of the measurement target 11.

  In the excitation electrode 22, first wire electrodes 21a to 21d are arranged on the same plane in parallel with each other at intervals. The measurement electrode 24 has second wire electrodes 23a to 23d arranged in parallel on the same plane at an interval from each other, and is provided to intersect with the first wire electrodes 21a to 21d. The plane on which the excitation electrode 22 is disposed and the plane on which the measurement electrode 24 is disposed are planes which are present in the tubular container 10 but are different from each other but are disposed in parallel at a predetermined interval. That is, the excitation electrode 22 and the measurement electrode 24 are arranged in a rectangular lattice shape with a distance from each other, and the wire mesh sensor 20 is obtained. However, the wire mesh sensor 20 is not limited to the above structure as long as the excitation electrode 22 and the measurement electrode 24 do not interfere with each other and do not hinder the measurement of the temperature change of the measurement target 11. For example, the wire electrodes and the electrodes do not have to be arranged in parallel with each other, and the mesh shape does not have to be rectangular.

  Further, in the present embodiment, the plurality of wire mesh sensors 20 are arranged in the tubular container 10 in parallel with a certain interval in the depth direction of the tubular container 10. Although the number of the wire mesh sensors 20 can be changed as appropriate according to the measurement target 11, it is preferable to provide a plurality of wire mesh sensors 20 from the viewpoint of measurement accuracy.

  As described above, in the wire mesh sensor 20, the excitation electrode 22 and the measurement electrode 24 are close to but not in contact with each other. Hereinafter, a region where the wire electrodes of each electrode are close to each other is referred to as an intersection for convenience. In the present embodiment, this intersection is the measurement point of the temperature change of the measurement object 11 ([1, 1], [2, 1], [3, 1], [4, 1],... [1, 4] , [2,4], [3,4], [4,4]). These measurement points exist in the space between the wire electrodes of each electrode. Specifically, as shown in FIG. 2A, for example, the measurement point [1,1] exists between the first wire electrode 21a and the second wire electrode 23a. That is, the wire mesh sensor 20 detects a temperature change of the measurement target 11 existing at each measurement point between the first wire electrode 21a and the second wire electrode 23a by a two-dimensional measurement distribution.

  As shown in FIGS. 1 and 2, measurement points ([1, 1], [2, 1], [3, 1], [4, 1],. ], [2, 4], [3, 4], [4, 4]) are distributed in a plane where a pair of the excitation electrode 22 and the measurement electrode 24 exist, and a plurality of wire mesh sensors 20 are formed. Many are formed in combination. That is, since the wire mesh sensor 20 is a multipoint electrode sensor, it is possible to detect a temperature change of the measurement target 11 at each measurement point by a three-dimensional measurement distribution. For example, it is possible to detect the presence or absence of a partial temperature change of the measurement target 11 by comparing the temperature change of the measurement target 11 for each wire mesh sensor 20 based on the two-dimensional measurement distribution. Therefore, the measuring device 1 can measure the temperature change of the measurement target 11 with higher accuracy.

  In the present embodiment, the mode using the excitation electrode 22 composed of the first wire electrodes 21a to 21d and the measurement electrode 24 composed of the second wire electrodes 23a to 23d is employed. A mode using an excitation electrode composed of the wire electrodes 23a to 23d and a measurement electrode composed of the first wire electrodes 21a to 21d may be adopted.

  Further, in the present embodiment, stainless steel (SUS304) is used as a material of the first wire electrodes 21a to 21d and the second wire electrodes 23a to 23d. The material is not particularly limited as long as the material does not deteriorate due to contact with 11 or a temperature change according to the measurement mode. Further, each wire electrode may be coated with a covering material made of an insulating material except for regions intersecting with each other, from the viewpoint of improving measurement sensitivity by reducing noise and preventing interference of the measurement device 1. Here, the region of each wire electrode other than the region that intersects each other is a region that does not participate in detection of a measurement signal reflecting each parameter described later and does not function as a measurement point. Examples of the insulating material that can be a coating material include a fluororesin, a paraxylylene resin, and an enamel, and the material can be appropriately selected as needed.

  The input means 30 includes a power supply 31, a changeover switch SP, and switches S1 to S4, and the first wire electrodes 21a to 21d connected to the switches S1 to S4 serve as input lines. In the input means 30, the excitation signal PI is supplied from the power supply 31 via the changeover switch SP, and the excitation signals PI are applied in order from the first wire electrodes 21a in the first row by the switches S1 to S4. Note that the configuration of the input unit 30 is not limited to the above as long as the excitation signal PI can be supplied to the first wire electrodes 21a to 21d, and can be appropriately changed as needed.

  The detection means 40 includes A / D converters 41a to 41d and a detection unit 42, and the second wire electrodes 23a to 23d connected to the A / D converters 41a to 41d become output lines. In the detection means 40, the excitation signal PI applied to the first wire electrodes 21a to 21d by the input means 30 is applied to the intersection of the first wire electrodes 21a to 21d and the second wire electrodes 23a to 23d, ie, measurement. Points ([1,1], [2,1], [3,1], [4,1] ... [1,4], [2,4], [3,4], [4,4] ]), The signals are converted into measurement signals PO1 to PO4 reflecting the temperature change of the measurement object 11 and output via the A / D converters 41a to 41d, respectively, and the measurement signals PO1 to PO4 are detected by the detection unit 42. Is done.

  FIG. 1 shows only the measurement signals PO1 to PO4 from the viewpoint of avoiding the complexity of the drawing. However, in practice, the excitation signal PI is converted into one measurement signal at one intersection, and this signal is The detection is performed by the detection unit 42. Each measurement signal is determined based on the detection timing. For example, the excitation signal PI applied to the first line of the first wire electrode 21a from the switch S1 is applied to each intersection, that is, each measurement point ([4,1], [3,1], [2,1], [1] , 1]). Therefore, the measurement signal first detected by the detection unit 42 is a signal converted at the measurement point [4, 1]. However, the detection timing of each measurement signal can be appropriately changed by opening and closing the switches S1 to S4.

  Here, the measurement signals PO1 to PO4 reflecting the temperature change of the measurement target 11 reflect, for example, a measurement parameter based on the temperature change of the measurement target 11, that is, a change in capacitance, inductance, or conductance. These parameters have eigenvalues for each substance, and the eigenvalues change according to the temperature of the substance. That is, since the capacitance, the inductance, or the conductance has a dependency on the temperature, the present embodiment utilizes the characteristics of such a substance. That is, by measuring these measurement parameters and performing arithmetic processing by the arithmetic processing means 50, it is possible to indirectly detect a temperature change of the measurement object 11. Note that the configuration of the detection unit 40 is not limited to the above as long as the measurement signals PO1 to PO4 can be output from the second wire electrodes 23a to 23d to the detection unit 42, and can be appropriately changed as needed.

  The arithmetic processing unit 50 includes an arithmetic processing unit 51 and a storage unit 52. In the arithmetic processing means 50, the arithmetic processing section 51 performs arithmetic processing on the measurement signals PO1 to PO4 output from the detection means 40 based on various data stored in the storage section 52, and based on the result, the measurement object 11 Is detected.

  Here, the various types of data stored in the storage unit 52 are data (temperature-dependent data) indicating the relationship between capacitance, inductance, or conductance, which is a measurement parameter of the measurement target 11, and temperature. That is, the storage unit 52 stores temperature dependency data of measurement parameters corresponding to the measurement target object 11, reads out temperature dependency data corresponding to the measurement signals PO1 to PO4 output from the detection unit 40, A temperature change of the measurement target 11 can be detected.

  In the present embodiment, the measurement parameter may be measured indirectly by measuring the voltage (potential) and the current without directly measuring the capacitance, inductance, or conductance, which is the measurement parameter of the measurement target 11. it can. That is, the capacitance, inductance, and conductance of the measurement target 11 can be calculated from the measured values of the voltage (potential) and the current. Then, it is possible to detect a temperature change of the measuring object 11 using the above-described temperature dependency data.

The capacitance Cp of the measuring object 11 can be calculated from the dielectric constant ε as shown in the following equation (1), and the dielectric constant ε is obtained by measuring the voltage V, the current I, and the following equation (2). ) To (4). Here, in the following equations (1) to (4), Cp is the capacitance of the measurement target 11, V is the measured voltage value of the measurement target 11, Q is the charge, and d is the distance between the first and second wire electrodes. , Ε is the permittivity of the measurement object 11, S is the area between the first and second wire electrodes, I is the measured current value of the measurement object 11, and t is the time.
Cp = εS / d (1)
V = Qd / εS (2)
I = Q / t (3)
ε = Idt / VS (4)

The inductance L can be calculated from the measured value V of the voltage, the measured value I of the current, and the following equations (5) and (6). However, in the following equations (5) and (6), V is the measured voltage value of the measurement object 11, L is the inductance of the measurement object 11, I is the measurement current value of the measurement object 11, and t represents time. .
V = L (dI / dt) (5)
L = V (dt / dI) (6)

The conductance G can be calculated from the measured value V of the voltage, the measured value I of the current, and the following equations (7) and (8). Here, in the following equations (7) and (8), R is the resistance value of the measurement object 11, V is the measurement voltage value of the measurement object 11, I is the measurement current value of the measurement object 11, and G is the conductance. Show.
R = V / I (7)
G = 1 / R = I / V (8)

  In addition, a voltage (potential) or a current is used as a measurement parameter of the measurement target 11, and data (voltage (potential) or current temperature dependency data) indicating a relationship between these and a temperature is stored in the storage unit 52, and the measurement target is measured. It is also possible to detect a temperature change of the object 11. For example, calibration data (see FIG. 4) indicating a change in the potential of the measurement object 11 with respect to the temperature in the storage unit 52, and temporal change data relating to a temporal change in the temperature created based on the calibration data (see FIG. 5). Is stored, and the temperature change of the measurement target 11 can be detected (measured) by the temperature change data stored in the storage unit 52 by the arithmetic processing unit 50. In the present embodiment, a voltage change (potential) is applied as a measurement parameter, and a calibration curve between the voltage (potential) and the temperature is created in advance, so that a temperature change of the measurement target 11 can be detected.

  The configuration of the arithmetic processing means 50 is not limited to the above as long as it can detect a temperature change of the measurement target 11 based on the measurement signals PO1 to PO4 output from the detection means 40, and may be appropriately changed as necessary. Can be done. For example, a known capacitance (dielectric constant), inductance or conductance measuring device may be applied to detect a temperature change of the measurement target 11. In addition, a known pH measuring device, pOH measuring device, DO measuring device, or the like may be used for measuring the characteristic value of the measurement target 11.

  Next, a method for measuring the temperature of the measuring object 11 using the measuring device 1 will be described in detail.

  First, in the measuring device 1, the measurement object 11 provided with the wire mesh sensor 20 is housed and held inside the tubular container 10, the input means 30 is connected to the excitation electrode 22 side, and the detection is performed on the measurement electrode 24 side. The arithmetic processing means 50 are connected via the means 40 respectively.

  Next, the excitation signal PI is supplied from the power supply 31 of the input means 30 via the changeover switch SP, and the excitation signals PI are applied in order from the first wire electrodes 21a in the first row by the switches S1 to S4. Thereby, the excitation signal PI applied to each of the first wire electrodes 21a to 21d is applied to the intersection (measurement point ([1, 1]) of the first wire electrodes 21a to 21d and the second wire electrodes 23a to 23d. , [2,1], [3,1], [4,1] ... [1,4], [2,4], [3,4], [4,4]) The signals are converted into measurement signals PO1 to PO4 reflecting the temperature change of 11. These signals are output from the second wire electrodes 23a to 23d to the A / D converters 41a to 41d.

  Next, after the A / D converters 41 a to 41 d A / D convert the measurement signals PO <b> 1 to PO <b> 4 reflecting the temperature change of the measurement target 11 output from the second wire electrodes 23 a to 23 d, the detection unit 42. Output to Then, these signals are detected by the detection unit 42 and output to the arithmetic processing unit 51.

  Next, the arithmetic processing unit 51 receives the measurement signals PO1 to PO4 that reflect the temperature change of the measurement target 11 output from the detection unit 42. Then, in the arithmetic processing unit 51, based on the data (temperature-dependent data) indicating the relationship between the capacitance and the inductance or the conductance, which are the measurement parameters of the measurement target 11, and the temperature stored in the storage unit 52, the measurement target 11 The arithmetic processing is performed on the measurement signals PO1 to PO4 reflecting the temperature change. That is, the arithmetic processing unit 51 reads the temperature dependency data corresponding to the measurement signals PO1 to PO4 output from the detection unit 40, and detects a temperature change of the measurement target 11. As a result, in the measuring device 1, each intersection (measurement point ([1, 1], [2, 1], [3, 1], [4, 1], ..., [1, 4], [2, 4] ], [3, 4], [4, 4]), the temperature change of the measurement target 11 can be measured.

  When measuring the pH of the measurement target 11 using the measurement device 1 of the present embodiment, the arithmetic processing unit 51 uses the measurement parameter of the measurement target 11 stored in the storage unit 52 such as capacitance, inductance, or conductance. Based on data (pH-dependent data) indicating the relationship between the measurement signals PO1 and PO4, the measurement signals PO1 to PO4 reflecting the pH change of the measurement object 11 are processed.

  When measuring the dissolved oxygen amount of the measurement target 11 using the measurement device 1 of the present embodiment, the arithmetic processing unit 51 uses the measurement parameters of the measurement target 11 stored in the storage unit 52 such as capacitance and inductance. Alternatively, based on data indicating the relationship between conductance and dissolved oxygen (dissolved oxygen dependence data), measurement signals PO1 to PO4 reflecting the change in the dissolved oxygen amount of the measurement target 11 are calculated.

  As described above, by using the measurement device 1 having the wire mesh sensor 20, the wire mesh sensor 20 is disposed in the measurement target 11, and the measurement signal reflecting the capacitance, inductance, or conductance of the measurement target 11 is reflected. PO1 to PO4 are subjected to arithmetic processing, and the temperature change of the measurement object 11, the change of the hydrogen ion concentration (pH), the change of the hydroxide ion concentration (pOH), the change of the dissolved oxygen concentration (DO), and the like are changed over time. It can be easily measured. In addition, by disposing the wire mesh sensor 20 in the measurement target 11, the two-dimensional measurement distribution can be appropriately changed according to the form of the measurement target 11, thereby performing measurement with higher flexibility. Can be. In addition, by disposing a plurality of wire mesh sensors 20 in the measurement target 11, the above-described temperature change and the like of the measurement target 11 can be detected with high accuracy by a three-dimensional measurement distribution.

  Next, the present invention will be described in more detail with reference to the following Examples and Comparative Examples.

(Wire mesh sensor)
FIG. 3 is a perspective view schematically showing a wire mesh sensor used in Examples 1 to 10 described later. As shown in FIG. 3, the wire mesh sensor 100 is a simplified version of the wire mesh sensor 20 according to the present embodiment for an experiment, and includes four wire electrodes (transmitter wires 121a and 121b and receiver wires 122a and 122b). ) Are alternately arranged in parallel and formed in a substantially square lattice shape (mesh shape) in the same manner as the measuring device 1 except that they are arranged inside the container 110 holding the measurement object 130. did. In the wire mesh sensor 100, the transmitter wires 121a and 121b are input lines for inputting excitation signals, respectively, and the receiver wires 122a and 122b are output lines for outputting measurement signals (here, signals based on voltage changes). . In each embodiment, stainless steel (SUS304) was used as a material of the transmitter wires 121a and 121b and the receiver wires 122a and 122b. In the wire mesh sensor 100, a portion where the wires are close to each other but not in contact with each other is defined as an intersection ([1a, 1b], [1a, 2b], [2a, 1b], [2a, 2b]). These were used as measurement points. In each of the embodiments described below, unless otherwise specified, an excitation signal is input to the transmitter wires 121a and 121b by input means (not shown), and these signals are output as measurement signals from the receiver wires 122a and 122b, respectively. The change of the voltage with respect to the measurement time was measured by a detecting means and an arithmetic processing means (not shown).

(Example 1)
In the first embodiment, the boiling water (100 ° C.), which is the measurement object 130, is filled in the container 110 of the wire mesh sensor 100, and then the cooling water is injected into the container 110 to rapidly cool the boiling water. Temperature changes were sensed, and the results are shown in FIG. FIG. 4 is a graph showing the relationship between the temperature of the boiling water and the measured potential in Example 1. An approximate expression (y = 0.0263x + 0.0734) showing the relationship between the temperature (x) of the boiling water and the measured potential (y) was obtained from the temperature sensing result of the boiling water shown in FIG. Then, a linear correlation equation represented by the following equation (9) was calculated from the approximate equation. Here, in the following equation (9), T represents the temperature of the boiling water, and V represents the measured potential of the boiling water.
T = (V−0.0734) /0.0263 (9)

  Next, the potential measurement changeover switch is switched OFF / ON twice every 1000 Hz / 30 seconds to perform temperature sensing a total of three times, and converted into a change with time in temperature based on the linear correlation equation obtained in FIG. The results are shown in FIG.

(Comparative Example 1)
In Comparative Example 1, a linear correlation equation was calculated from the relationship between the measured potential (y) and the temperature (x) of boiling water in the same manner as in Example 1 except that a thermocouple was used instead of the wire mesh sensor 100. FIG. 5 shows the result of conversion into a change with time in temperature based on this. FIG. 5 is a graph showing the change over time in the temperature of boiling water in each sensor of Example 1 and Comparative Example 1.

  As shown in FIG. 5, it can be confirmed that the wire mesh sensor 100 of the first embodiment functions as a temperature sensor for measuring the temperature in the same manner as the thermocouple of the first comparative example. It was confirmed that it was possible to acquire data in a two-dimensional distribution using the sensor 100. Further, in the wire mesh sensor 100, the spatial resolution can be increased by the interval between the intersections (measurement points [1a, 1b], [1a, 2b], [2a, 1b], [2a, 2b]), and time can be increased. It is considered that the resolution is theoretically possible up to the order of 10,000 Hz.

(Example 2)
In Example 2, a continuous injection test of hot water was performed on the wire mesh sensor 100 based on the conditions (test parameters) shown in Table 1 below. Specifically, the inside of the container 110 of the wire mesh sensor 100 was filled in advance with room temperature pure water (liquid phase) as the measurement object 130. Next, on the top of the measurement object 130 corresponding to the obtained intersection (measurement points [1a, 1b], [1a, 2b], [2a, 1b], [2a, 2b]) in the measurement object 130 , 95 ° C warm water was continuously injected. That is, the hot water injection field was set near the measurement point. Then, a change in voltage in the wire mesh sensor 100 based on the injection of hot water was measured, and the result is shown in FIG. Note that the downward arrow at the top of FIG. 6 indicates that the injection of warm water into the measurement object 130 has started at that time. The measured voltage value is a measured value at an arbitrary measurement point selected from the above-described four measurement points.

  FIG. 6 is a graph showing temperature sensitivity when hot water of 95 ° C. is forcibly injected in Example 2. As shown in FIG. 6, when the magnitude of the voltage value of the measurement object 130 is confirmed up to three seconds before the injection of the hot water into the measurement object 130 (liquid phase), there is no large change in the voltage value. At the time of continuous injection, the voltage value near each measurement point increased. That is, as the temperature of the measuring object 130 increases, the voltage value also increases.

  In Example 2, the voltage value of the measurement target 130 was changed by forcibly injecting 95 ° C. hot water into the normal temperature pure water, which is the measurement target 130 on which the wire mesh sensor 100 was disposed. That is, it was confirmed that the temperature change of the measurement target 130 can be detected by arranging the wire mesh sensor 100 on the measurement target 130 and measuring the change in the voltage value.

(Example 3)
In the third embodiment, the position corresponds to a position 10 cm away from the intersection (measurement points [1a, 1b], [1a, 2b], [2a, 1b], [2a, 2b]) in the obtained measurement object 130. A continuous hot water injection test was performed in the same manner as in Example 2 except that hot water at 95 ° C. was continuously injected into the upper portion of the measurement object 130. Then, a change in voltage in the wire mesh sensor 100 based on the injection of hot water was measured, and the result is shown in FIG. The measured voltage value is a measured value at an arbitrary measurement point selected from the above-described four measurement points.

  FIG. 7 is a graph showing the temperature sensitivity when 95 ° C. hot water is injected by natural convection in Example 3. As shown in FIG. 7, when the magnitude of the voltage value at the measurement object 130 is confirmed up to 5 seconds before hot water is injected into the measurement object 130 (liquid phase), there is no large change in the voltage value here. , The voltage value gradually increased. That is, due to natural convection using the temperature gradient of the measurement object 130 as a driving force, the temperature near each measurement point of the measurement object 130 rises and the voltage value also increases, so that the voltage value inside the measurement object 130 increases and decreases. It could be measured.

  In the third embodiment, 95 ° C. hot water is injected from a point distant from each measurement point into room temperature pure water, which is the measuring object 130 on which the wire mesh sensor 100 is disposed, so that the voltage value of the measuring object 130 is increased. Gradually changed. That is, it was confirmed that the wire mesh sensor 100 was disposed on the measurement target 130, and even when the change in the voltage value was small, measurement could be performed, and a small temperature change of the measurement target 130 could be detected. . Therefore, in Example 3, it was confirmed that even if a small change in temperature of the measurement target 130 could be detected by disposing the wire mesh sensor 100 in the same manner as in Example 2.

(Example 4)
In the fourth embodiment, a 10 × 10 wire mesh sensor using ten transmitter wires and ten receiver wires is used, and the container 110 is filled with room temperature pure water as the measurement target 130 to make it visually easy to understand. A continuous hot water injection test was performed in the same manner as in Example 3 except that 90 ° C. pure water (hot water) containing methylene blue was continuously injected from one of the four corners of the container 110. Then, a change in matrix temperature in a 10 × 10 wire mesh sensor based on the injection of hot water was measured, and the results are shown in FIG. FIGS. 8A and 8B are results showing the temperature sensitivity of the 10 × 10 wire mesh sensor according to the fourth embodiment. FIGS. 8A to 8D show the measurement results of the matrix temperature change, and FIGS. In addition, still images corresponding to (a) to (d) showing changes over time of the temperature difference of the pure water in the container 110 are shown. FIGS. 8A to 8D show a difference in temperature due to a change in color. In addition, methylene blue is used as a colorant that makes it easy to visually confirm the movement of warm water in the container 110, and does not have any effect on a change (substance change) of the measurement object 130 including temperature. .

(Example 5)
In the fifth embodiment, the container 110 is filled with pure water (pH = 6.35) as the measurement object 130, and 0.001 wt% containing methylene blue from one of the four corners of the container 110 for easy visual recognition. A continuous injection test of an aqueous solution having a pH different from that of pure water was conducted in the same manner as in Example 4 except that an aqueous sodium hydroxide solution (pH = 10.34) was continuously injected. Then, a change in matrix pH in a 10 × 10 wire mesh sensor based on injection of aqueous solutions having different pH values was measured, and the results are shown in FIG. FIG. 9 shows the results showing the pH sensitivity of the 10 × 10 wire mesh sensor in Example 5, (a) to (d) show the measurement results of the matrix pH change, and (e) to (h) show the results. In addition, still images corresponding to (a) to (d) showing changes with time of the pH difference of pure water in the container 110 are shown. FIGS. 9A to 9D show a difference in pH value due to a change in color.

(Example 6)
In the sixth embodiment, degassed water (DO = 1.65 mg / L) filled with pure water and evacuated as the measurement object 130 in the container 110 is used. In the same manner as in Example 4 except that methylene blue-containing saturated water (DO = 8.49 mg / L) was continuously injected from one side, a continuous aqueous solution having a different dissolved oxygen (DO) from pure water was obtained. An injection test was performed. Then, a change in the amount of dissolved oxygen in the matrix in a 10 × 10 wire mesh sensor based on the injection of aqueous solutions having different amounts of dissolved oxygen was measured, and the results are shown in FIG. FIG. 10 is a result showing the dissolved oxygen amount sensitivity of the 10 × 10 wire mesh sensor in Example 6, (a) to (d) are measurement results of changes in the amount of dissolved oxygen in the matrix, and (e) to (e). (H) shows the still images corresponding to (a) to (d) showing the change with time of the dissolved oxygen amount difference of the pure water in the container 110. FIGS. 10A to 10D show the difference in the amount of dissolved oxygen due to a change in color.

  The detailed measurement of the temperature using the wire mesh sensor becomes possible by the relationship between the result of the matrix temperature change in FIG. 8 and the potential calibrated by the calibration curve in FIG. Further, detailed measurement of pH using a wire mesh sensor becomes possible based on the relationship between the result of the matrix pH change in FIG. 9 and the potential calibrated by the calibration curve in FIG. Further, the DO can be measured in detail by the relationship between the result of the change in the amount of dissolved oxygen (DO) in the matrix in FIG. 10 and the potential calibrated by the calibration curve in FIG.

(Example 7)
The seventh embodiment is different from the first embodiment except that a solution having a different hydrogen ion concentration (pH) is used as the measurement object 130 and a linear correlation equation is calculated from the relationship between the measured potential (y) and the pH (x) of the solution. The test was performed similarly. In Example 7, conversion into a change with time in pH was performed based on the obtained linear correlation equation, and the result is shown in FIG. FIG. 11 is a graph showing the relationship between the solution pH and the measured potential in Example 7. As shown in FIG. 11, it was confirmed that the wire mesh sensor 100 of Example 7 functions as a pH sensor for measuring pH.

(Example 8)
Example 8 Example 8 differs from Example 1 in that solutions having different dissolved oxygen amounts (DO) were used as the measurement target 130, and a linear correlation equation was calculated from the relationship between the measured potential (y) and DO (x) of the solution. The test was performed similarly. In Example 8, DO was converted into a change with time based on the obtained linear correlation equation, and the result is shown in FIG. FIG. 12 is a graph showing the relationship between the dissolved oxygen amount of the solution and the measured potential in Example 8. As shown in FIG. 12, it was confirmed that the wire mesh sensor 100 of Example 8 functions as a DO sensor that measures DO.

  In addition, since the pH value and the DO value change due to the chemical reaction or evaporation of the substance, strict evaluation of the electrical conductivity, the potential of the wire mesh sensor, and the like is performed by using the various sensors of Embodiments 7 and 8. Can be.

(Example 9)
In the ninth embodiment, the container 110 of the wire mesh sensor 100 is filled with a 0.005 wt% aqueous solution of sodium hydroxide (pH = 8.9, conductivity = 300 μS / cm), which is the object 130 to be measured, and then its concentration is increased. The conductivity at 25 ° C. of the aqueous sodium hydroxide solution when the amount was slightly increased was measured, and the results are shown in FIG. FIG. 13 is a graph showing the relationship between the pH and the conductivity when the concentration is changed based on a 0.005 wt% aqueous sodium hydroxide solution. As shown in FIG. 13, it was found that the pH and the conductivity of the aqueous sodium hydroxide solution showed a correlation. In addition, according to the result of Example 9, since there is conductivity sensitivity in pH, simultaneous measurement with temperature can be performed in combination with the temperature sensor of Example 1 and more accurate measurement can be performed. . Similarly, since pOH (hydroxide ion concentration) and DO (dissolved oxygen amount) also have conductivity sensitivity, these pOH sensors and DO sensors can be combined with the temperature sensor of the first embodiment.

(Example 10)
In Example 10, after filling the container 110 of the wire mesh sensor 100 with aqueous sodium hydroxide solutions having different concentrations as the measurement object 130, the conductivity of the aqueous sodium hydroxide solution filled in the container 110 was measured, FIG. 14 shows the result. FIG. 14 is a graph showing the relationship between pH and conductivity when the concentration of the aqueous sodium hydroxide solution is changed. As shown in FIG. 14, similarly to the temperature of Example 1, it was found that the concentration of the aqueous sodium hydroxide solution and the electrical conductivity showed a correlation. Accordingly, when the wire mesh sensor 100 of the first embodiment is used as a sensor for temperature or the like, particularly when the measurement object 130 is a solution, by adding a buffer such as sodium hydroxide, the conductivity with respect to temperature change can be improved. The measurement accuracy can be improved by increasing the stability of the rate and improving the S / N.

  INDUSTRIAL APPLICABILITY The present invention can be widely used in industrial fields to which sensors such as temperature, pH, pOH, and DO are applied.

DESCRIPTION OF SYMBOLS 1 Measuring device 10 Tubular container 11, 130 Measurement object 20, 100 Wire mesh sensor 21a, 21b, 21c, 21d First wire electrode 22 Excitation electrode 23a, 23b, 23c, 23d Second wire electrode 24 Measurement electrode 30 Input Means 31 Power supply 40 Detecting means 41a, 41b, 41c, 41d A / D converter 42 Detecting unit 50 Arithmetic processing unit 51 Arithmetic processing unit 52 Storage unit 110 Container 121a, 121b Transmitter wire 122a, 122b Receiver wire SP Switch S1, S2 , S3, S4 switch

Claims (5)

Placed in the measurement object,
An excitation electrode including a plurality of first wire electrodes disposed at intervals from each other; and a plurality of excitation electrodes disposed at intervals from each other and intersecting the plurality of first wire electrodes. A wire mesh sensor having a measurement electrode composed of a second wire electrode;
Input means for inputting an excitation signal to the first wire electrode;
Detecting means for detecting a measurement signal reflecting the capacitance, inductance or conductance output from the second wire electrode;
Arithmetic processing means for arithmetically processing the measurement signal reflecting the capacitance, inductance or conductance and detecting a temperature change of the object to be measured.   The temperature sensor according to claim 1, wherein the measurement target has a buffer added thereto.   The arithmetic processing means performs arithmetic processing on a measurement signal output from the second wire electrode to measure a change in a hydrogen ion concentration, a change in a hydroxide ion concentration, or a change in a dissolved oxygen concentration of the measurement object. The temperature sensor according to claim 1 or 2, wherein:   The temperature according to any one of claims 1 to 3, wherein the first wire electrode and the second wire electrode are coated with an insulating material except for a region intersecting with each other. Sensors. An excitation electrode including a plurality of first wire electrodes disposed at intervals from each other; and a plurality of excitation electrodes disposed at intervals from each other and intersecting the plurality of first wire electrodes. A wire mesh sensor having a measurement electrode composed of a second wire electrode is disposed in the measurement object,
Inputting an excitation signal to the first wire electrode;
Detecting a measurement signal reflecting the capacitance, inductance or conductance output from the second wire electrode,
Detecting a change in temperature, a change in hydrogen ion concentration, a change in hydroxide ion concentration, and / or a change in dissolved oxygen concentration of the measurement object based on the measurement signal reflecting the capacitance, inductance, or conductance. Characteristic temperature measurement method.