Measuring device including a temperature control element

Abstract

To provide a technique of stably measuring the concentration or the physical property of a measurement target substance in soil.SOLUTION: A measurement device according to an aspect of the present disclosure has a temperature control element, and includes: a plurality of electrodes provided in soil at least partially; and a temperature control element for controlling ambient temperatures; and a measurement unit for measuring the potentials of at least two of the electrodes and measuring one of the concentration and the physical property of a measurement target substance in soil on the basis of the measured potentials. The temperature control element is provided so that soil is between the temperature control element and one of the two electrodes.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a measuring device including a temperature control element.

Background Art

[0002] Measuring devices capable of measuring the concentration or physical properties of ions or molecules have been disclosed (for example, Patent Documents 1-3). In addition, devices having a temperature control element capable of controlling the ambient temperature have been disclosed (for example, Patent Documents 4-6).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Summary of the Invention

Problems to be Solved by the Invention

[0004] For example, in the case of the measuring device described in Patent Document 1, a solution contacts the working electrode to measure the potential difference between the working electrode and the reference electrode, and based on the measured potential difference, the concentration or physical properties of the ions to be measured in the solution are calculated. Therefore, when such a measuring device is installed in soil to measure the concentration or physical properties of the substance to be measured in the soil, it is conceivable that the measurement becomes unstable when the water content in the soil is low.

[0005] The present invention has been made in view of such circumstances, and an object thereof is to provide a technique capable of stably measuring the concentration or physical properties of a substance to be measured in soil.

Means for Solving the Problems

[0006] In order to solve the above-described problems, the present invention employs the following configuration.

[0007] That is, a measuring device according to one aspect of the present invention is a measuring device including a temperature control element, and includes a plurality of electrodes, at least a part of which is provided in soil, a temperature control element capable of controlling the surrounding temperature, and a measuring unit that measures the potentials of at least any two of the plurality of electrodes and measures the concentration or physical properties of a substance to be measured contained in the soil based on the measured potentials. The temperature control element is provided such that a part of the soil is interposed between the temperature control element and at least any one of the two electrodes.

[0008] According to this configuration, the temperature control element can cool the temperature of the surrounding soil. Therefore, water vapor contained in the soil interposed between the temperature control element and at least any one of the two electrodes condenses. Therefore, when a voltage is applied between any two of the plurality of electrodes, the substance to be measured dissolved in water moves. Therefore, a potential corresponding to the concentration of the substance to be measured is generated at the two electrodes. Therefore, even for soil with a low moisture content, it is possible to stably measure the concentration or physical properties of the substance to be measured based on the potential generated at the two electrodes.

[0009] In the measuring device according to the above aspect, the plurality of electrodes have an electrode set including a pair of a first electrode and a second electrode, and the first electrode and the second electrode are provided in the soil. The substance to be measured moves in the direction in which the first electrode exists when a voltage is applied between the first electrode and the second electrode, and the temperature control element may be provided such that a part of the soil is interposed between the temperature control element and the first electrode.

[0010] According to this configuration, water vapor contained in the soil intervening between the temperature control element and the first electrode condenses. Therefore, when a voltage is applied between the first electrode and the second electrode so that the measurement target substance dissolved in water moves in the direction where the first electrode is located, a potential corresponding to the concentration of the measurement target substance is generated at the first electrode and the second electrode. Therefore, even for soil with a low water content, it is possible to stably measure the concentration or physical properties of the measurement target substance based on the potentials generated at the first electrode and the second electrode.

[0011] In the measuring device according to the above aspect, the temperature control element has a heat radiating portion that radiates heat to the surroundings and a cooling portion that absorbs heat from the surroundings, at least a part of the heat radiating portion is disposed in the atmosphere, at least a part of the cooling portion is provided in the soil, and it may be disposed closer to the deeper part of the soil than the heat radiating portion.

[0012] According to this configuration, in winter when the atmospheric temperature is lower than the internal temperature of the soil, the release of the energy of the soil when cooling the soil around the working electrode and the reference electrode is promoted. Therefore, even for soil with a low water content, it is possible to measure the concentration or physical properties of the measurement target substance while suppressing the power consumption of the measuring device.

[0013] In the measuring device according to the above aspect, the temperature control element has a heat radiating portion that radiates heat to the surroundings and a cooling portion that absorbs heat from the surroundings, and the heat radiating portion may be disposed closer to the deeper part of the soil than the cooling portion.

[0014] According to this configuration, in summer when the deep temperature is lower than the surface temperature of the soil, the release of the energy of the soil when cooling the soil around the working electrode and the reference electrode is promoted. Therefore, even for soil with a low water content, it is possible to measure the concentration or physical properties of the measurement target substance while suppressing the power consumption of the measuring device.

[0015] In the measuring device according to the above aspect, it may further include a temperature detection element capable of detecting temperature, and the temperature detection element may be provided on the back surfaces of the surfaces of the first electrode and the second electrode facing the soil, respectively.

[0016] According to this configuration, the temperature characteristics of the working electrode and the reference electrode can be corrected by the temperature detected by the temperature detection element. Therefore, even for soil with a low water content, the measurement accuracy of the concentration or physical properties of the substance to be measured is improved.

[0017] In the measuring device according to the above aspect, the cooling unit may be in contact with the soil, and at least a part of the surface in contact with the soil may be hydrophobic.

[0018] According to this configuration, it is possible to prevent condensed water from adhering to the outer surface of the cooling unit. Therefore, even for soil with a low water content, the moisture contained in the soil can be used for measuring the concentration or physical properties of the substance to be measured without being wasted.

[0019] The measuring device according to the above aspect may further include a power source that supplies power to the measuring unit.

[0020] According to this configuration, the measuring device can operate without being connected to a power source outside the measuring device. Therefore, even when the area of the soil is so large that it is difficult to connect to a power source outside the measuring device, it is possible to measure the concentration or physical properties of the substance to be measured.

Advantages of the Invention

[0021] According to the present invention, it is possible to provide a technique for stably measuring the concentration or physical properties of a substance to be measured in soil.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

[0023] [Embodiment] FIG. 1 illustrates an overview of the measuring device 1 according to the present embodiment. FIG. 1(A) is an example of an external perspective view of the measuring device 1. FIG. 1(B) is an example of a side view of the measuring device 1. The measuring device 1 has a portable size and is arranged to be inserted into the soil 11 with a low water content. Then, the concentration of the substance that responds immediately to the growth of the crops contained in the soil 11 is measured. The substance that responds immediately to the growth of the crops is, for example, nitrate nitrogen (an example of the "substance to be measured" in the present disclosure).

[0024] More specifically, the measuring device 1 has an electrode set including a pair of working electrodes 2 and a reference electrode 3. Here, the water content of the soil 11 is, for example, less than 20%. Further, the working electrode 2 is a so-called ion-selective electrode, and its surface is covered with a sensitive film. The sensitive film is a film that can selectively capture nitrate nitrogen. The sensitive film is, for example, a lacquer matrix liquid film or a PVC (polyvinyl chloride) matrix liquid film. The reference electrode 3 is, for example, a silver-silver chloride electrode immersed in KCL (potassium chloride). The working electrode 2 is an example of the "first electrode" in the present disclosure. The reference electrode 3 is an example of the "second electrode" in the present disclosure. um). The working electrode 2 is an example of the "first electrode" in the present disclosure. The reference electrode 3 is an example of the "second electrode" in the present disclosure.

[0025] In addition, the measuring device 1 has a measurement unit 4. The measurement unit 4 is provided in the atmosphere outside the soil above the working electrode 2 and the reference electrode 3. The measurement unit 4 is electrically connected to the working electrode 2 and the reference electrode 3, respectively, and the connection parts are protected by a case 5. The measurement unit 4 is also electrically connected to an external power source of the measuring device 1 (not shown). The diameter of the case 5 is, for example, 2 cm or less. The measurement unit 4 is an example of the "measurement unit" in the present disclosure.

[0026] The measurement unit 4 is provided with a processor such as a CPU, a storage device such as a RAM and a ROM, etc. Various programs and the like are stored in the storage device. Then, the stored program is loaded into the working area of the main storage device and executed. And through the execution of the program, each component such as the application of voltage between the working electrode 2 and the reference electrode 3, the measurement of the potentials of the working electrode 2 and the reference electrode 3, and the calculation of the concentration of nitrate nitrogen from the potential difference between the working electrode 2 and the reference electrode 3 are controlled, so that each function that meets a predetermined purpose can be realized.

[0027] In addition, the measuring device 1 has a Peltier element 6 (an example of the "temperature control element" of the present disclosure). The Peltier element 6 is provided on the outer surface of the case 5 such that the upper part is the heat dissipation part 7 and the lower part is the cooling part 8. Note that the heat dissipation part 7 is provided so as to be exposed to the atmosphere outside the soil 11. Also, the cooling part 8 is provided on the soil 11 side rather than the heat dissipation part 7, and a part of the lower part is buried in the soil 11. Also, the Peltier element 6 is provided such that a part of the soil 11 is interposed between the cooling part 8 and the working electrode 2 is interposed. Note that the Peltier element 6 is electrically connected to the measurement unit 4.

[0028] [Operation example] [[ID=**13**]]Next, an outline of the measurement operation of the measuring device 1 will be exemplified. First, the measurement unit 4 controls the current applied to the Peltier element 6. Then, when a predetermined amount of current flows through the Peltier element 6, an endothermic reaction occurs in the cooling part 8. Therefore, the surrounding soil 11 below the cooling part 8 is cooled. On the other hand, in the heat dissipation part 7, heat is dissipated to the atmosphere conversely.

[0029] Figure 2 is an example of a graph showing the relationship between temperature and the amount of saturated water vapor. As shown in Figure 2, as the temperature decreases, the amount of saturated water vapor also decreases. Therefore, when the cooling part 8 is cooled, water vapor condenses in the surrounding soil 11 below the cooling part 8.

[0030] Subsequently, the measurement unit 4 applies a voltage across the working electrode 2 and the reference electrode 3. The voltage is applied such that the working electrode 2 serves as the anode and the reference electrode 3 serves as the cathode. Then, since the nitrate nitrogen that exists between the working electrode 2 and the reference electrode 3 and is bound to water is an anion, it moves in the direction of the working electrode 2, which is the anode. The nitrate nitrogen is then captured by the sensing film covering the outer surface of the working electrode 2. The measurement unit 4 measures the potential of the working electrode 2 and the potential of the reference electrode 3, and calculates the potential difference between the two potentials. Then, the measurement unit 4 relatively calculates the concentration of nitrate nitrogen contained in the soil 11 with respect to the reference concentration of nitrate nitrogen by comparing the calculated potential difference with the reference potential difference. Note that the concentration of nitrate nitrogen contained in the soil 11 may be calculated from the absolute value of the potential difference without comparing the calculated potential difference with the reference potential difference.

[0031] [Function and Effect] According to the measurement device 1 as described above, by cooling the soil 11 with the cooling unit 8, dew water is generated in the soil 11 to increase the moisture content, and then the concentration of nitrate nitrogen is measured. Therefore, even in the soil 11 with a low volumetric water content, it is possible to stably measure the concentration of nitrate nitrogen, which is a substance that responds immediately to the growth of crops. Also, the concentration of nitrate nitrogen can be measured in real time. Therefore, the concentration of nitrate nitrogen can be precisely controlled in real time to improve the yield and quality of crops.

[0032] Also, according to the measurement device 1 as described above, the heat dissipation unit 7 is disposed in the atmosphere. Therefore, in winter when the atmospheric temperature is lower than the internal temperature of the soil 11, the release of energy from the soil 11 when cooling the soil 11 around the working electrode 2 and the reference electrode 3 is promoted. Therefore, it is possible to measure nitrate nitrogen in the soil 11 with a low volumetric water content while suppressing the power consumption of the measurement device 1.

[0033] [Modification 1] FIG. 3 illustrates an overview of the measurement device 1A according to the first modification. FIG. 3(A) illustrates an overview of the front view of the measurement device 1A. FIG. 3(B) illustrates an overview of the side view of the measurement device 1A.

[0034] In the measuring device 1A, as shown in FIG. 3, the entire Peltier element 6A is provided inside the soil 11. Further, the Peltier element 6A is provided such that the heat radiating portion 7A is closer to the deeper part of the soil 11 than the cooling portion 8A.

[0035] [Operation and Effect] According to the measuring device 1A as described above, in summer when the temperature of the deeper part of the soil 11 is lower than the surface temperature of the soil 11, the release of energy from the soil 11 when cooling the soil 11 around the working electrode 2A and the reference electrode 3A is promoted. Therefore, it is possible to measure the concentration of nitrate nitrogen in the soil 11 with a low volumetric water content while suppressing the power consumption of the measuring device 1A.

[0036] [Modification 2] FIG. 4 is an example of a partially enlarged view of the working electrode 2B and the reference electrode 3B of the measuring device 1B according to the second modification. The measuring device 1B according to the second modification has the same configuration as the measuring device 1 according to the embodiment. Further, in the measuring device 1B, as shown in FIG. 4, a temperature detection element 9 is provided on the back surface of the surface of the working electrode 2B and the reference electrode 3B facing the soil 11.

[0037] [Operation and Effect] According to the measuring device 1B as described above, the temperature characteristics of the working electrode 2B and the reference electrode 3B when the soil 11 is cooled by the Peltier element 6B can be corrected by the temperature detected by the temperature detection element 9. Therefore, it is possible to measure the concentration of nitrate nitrogen with high accuracy even in the soil 11 with a low volumetric water content. Further, since the temperature detection element 9 is arranged on the back surfaces of the working electrode 2B and the reference electrode 3B, it is suppressed that the application of the voltage between the working electrode 2B and the reference electrode 3B is adversely affected.

[0038] [Modification 3] FIG. 5 illustrates the outline of the measuring device 1C according to the third modification. The measuring device 1C according to the third modification has the same configuration as the measuring device 1A according to the first modification. Further, a hydrophobic region 10 is provided on a part of the outer surface of the cooling portion 8C of the measuring device 1C.

[0039] [Function and Effect] According to the measuring device 1C as described above, by cooling the soil 11 with the Peltier element 6C, it is possible to prevent condensed water from adhering to the surface of the cooling part 8C. Therefore, the soil moisture in the soil 11 with a low volumetric water content is utilized for measuring the concentration of nitrate nitrogen at the working electrode 2C without being wasted.

[0040] [Modification Example 4] FIG. 6 illustrates an overview of the measuring device 1D according to the fourth modification example. The measuring device 1D according to the fourth modification example has the same configuration as the measuring device 1A according to the first modification example. Further, the measuring device 1D has a self - contained power source 12. The self - contained power source 12 is provided, for example, above the measuring unit 4D. And the self - contained power source 12 supplies power to the measuring unit 4D.

[0041] [Function and Effect] According to the measuring device 1D as described above, the measuring device 1D can operate without being connected to a power source outside the measuring device 1D. Therefore, it is possible to measure the concentration of nitrate nitrogen even in a wide area of soil 11 with a low volumetric water content where it is difficult to supply power from an external power source.

[0042] [Other Modification Examples] In the above-described embodiment, one set of an electrode group composed of a pair of working electrodes 2 and reference electrodes 3 is provided, but a plurality of sets of electrode groups composed of a pair of electrodes may be provided. Further, the lower portions of the working electrode 2 and the reference electrode 3 may be buried in the soil 11, and the concentration of nitrate nitrogen inside the soil 11 may be measured. Further, the Peltier element 6 may be provided such that a part of the soil 11 is interposed between the cooling unit 8 and the reference electrode 3. Further, as an alternative to the Peltier element 6, other temperature control means capable of cooling the surrounding soil 11 may be provided. Further, an ion-selective field-effect transistor may be provided at the tip of the electrode group. Further, in the above-described embodiment, an example of measuring the concentration of nitrate nitrogen is shown, but the concentration of other substances may be measured. In such a case, the sensing film is changed to a film that selectively captures other substances. Further, using the potential information of the working electrode 2 and the reference electrode 3, physical properties such as the diffusion coefficient of nitrate nitrogen may be measured. Further, the concentration or physical properties of nitrate nitrogen may be measured using only the potential information of the working electrode 2. Further, the measuring device 1 does not have to be of a portable size.

[0043] The matters described in the embodiments and modifications disclosed above can be combined with each other.

Explanation of Reference Numerals

[0044] 1, 1A, 1B, 1C, 1D: Measuring device 2, 2A, 2B, 2C: Working electrode 3, 3A, 3B: Reference electrode 4, 4D: Measurement unit 5: Case 6, 6A, 6B, 6C: Peltier element 7, 7A: Heat dissipation unit 8, 8A, 8C: Cooling unit 9: Temperature detection element 10: Hydrophobic region 11: Soil 12: Self-powered source

Claims

1. A measuring device comprising a temperature control element, a plurality of electrodes, at least a part of which is provided in the soil, a temperature control element capable of controlling the ambient temperature, a measuring unit that measures the potentials of at least any two of the plurality of electrodes and measures the concentration or physical properties of a measurement target substance contained in the soil based on the measured potentials, wherein the temperature control element is provided such that a part of the soil is interposed between the temperature control element and at least any one of the two electrodes, a measuring device.

2. The plurality of electrodes have an electrode set consisting of a pair of a first electrode and a second electrode, the first electrode and the second electrode are provided in the soil, the measurement target substance moves in the direction in which the first electrode exists when a voltage is applied between the first electrode and the second electrode, wherein the temperature control element is provided such that a part of the soil is interposed between the temperature control element and the first electrode, The measuring device according to claim 1.

3. The temperature control element, has a heat radiating part that radiates heat to the surroundings, and a cooling part that absorbs heat from the surroundings, at least a part of the heat radiating part is disposed in the atmosphere, at least a part of the cooling part is provided in the soil and is disposed closer to the deeper part of the soil than the heat radiating part, The measuring device according to claim 2.

4. The temperature control element, has a heat radiating part that radiates heat to the surroundings, and a cooling part that absorbs heat from the surroundings, wherein the heat radiating part is disposed closer to the deeper part of the soil than the cooling part, The measuring device according to claim 2.

5. further comprising a temperature detection element capable of detecting temperature, wherein the temperature detection element is provided on the back surface of each of the surfaces of the first electrode and the second electrode facing the soil, The measuring device according to claim 2.

6. The cooling part is in contact with the soil, and at least a part of the surface in contact with the soil is hydrophobic, The measuring device according to claim 3 or 4.

7. further comprising a power supply that supplies power to the measuring unit, The measuring device according to claim 3 or 4.

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