Detection system

Abstract

A detection system 1 comprises: a thermoelectric conversion element 2 that generates an electromotive force due to a temperature difference; and a processing device 6. The processing device 6 executes: an acquisition step for acquiring the value of the electromotive force generated in the thermoelectric conversion element 2 (S1); and a correction step for correcting the value of the electromotive force acquired in the acquisition step (S1) using a correction formula (1) (S3) if the temperature difference increases due to an increase in the outside air temperature (S2: YES) and correcting the value of the electromotive force acquired in the acquisition step (S1) using a correction formula (2) (S4) if the temperature difference decreases due to an increase in the outside air temperature (S2: NO).　Collection formula (1): V2 = V1 - S × (TA - TA0) Collection formula (2): V2 = V1 + S × (TA - TA0) (In the correction formula (1) and the correction formula (2), V1 represents the value of the electromotive force before correction. V2 represents the value of the electromotive force after correction. S represents the value of the electromotive force per temperature difference of 1°C of the thermoelectric conversion element 2. TA represents the actually measured value of the outside air temperature. TA0 represents a reference value for the outside air temperature.)

Description

Detection system

[0001] This invention relates to a detection system.

[0002] Conventionally, sensor modules are known that include a thermoelectric conversion member that generates an electromotive force due to a temperature difference, a conversion circuit that converts the electromotive force of the thermoelectric conversion member into a signal, and a control device capable of recording the signal converted by the conversion circuit (see Patent Document 1 below).

[0003] International Publication No. 2023 / 127590

[0004] When attempting to detect temperature changes in an object using a sensor module such as the one described in Patent Document 1, monitoring the measured value of the electromotive force of the thermoelectric conversion element is considered.

[0005] However, the measured electromotive force of a thermoelectric conversion component fluctuates with temperature differences. For example, if the subject is insulation material for a pipe, even if the temperature of the fluid flowing through the pipe remains constant and the insulation performance of the insulation material has not deteriorated, fluctuations in the outside temperature may cause the electromotive force of the thermoelectric conversion component to decrease. In that case, it may become difficult to accurately detect temperature changes in the insulation material.

[0006] This invention provides a detection system that can accurately detect temperature changes in an object.

[0007] The present invention [1] is a detection system comprising a thermoelectric conversion element that generates an electromotive force in response to a temperature difference, and a processing device, wherein the processing device performs an acquisition step of acquiring the value of the electromotive force generated in the thermoelectric conversion element, and a correction step of correcting the value of the electromotive force acquired in the acquisition step using the following correction formula (1) when the temperature difference increases due to a rise in ambient temperature, and correcting the value of the electromotive force acquired in the acquisition step using the following correction formula (2) when the temperature difference decreases due to a rise in ambient temperature.

[0008] Correction formula (1): V ２ = V １ -S × (T Ａ -T Ａ０ ) Correction formula (2): V ２ = V １ +S × (T Ａ -T Ａ０), (In the above correction formula (1) and the above correction formula (2), V １ represents the value of the electromotive force before correction. V ２ represents the value of the electromotive force after correction. S represents the value of the electromotive force per 1°C of temperature difference of the thermoelectric conversion element. T Ａ represents the measured value of the outside air temperature. T Ａ０ represents the reference value of the outside air temperature.)

[0009] According to such a configuration, when the temperature difference increases due to an increase in the outside air temperature, the value of the electromotive force acquired by the processing device in the acquisition step (the value V of the electromotive force before correction １ ), the electromotive force corresponding to the temperature difference due to the fluctuation of the outside air temperature (= S × (T Ａ − T Ａ０ )) is subtracted.

[0010] On the other hand, when the temperature difference decreases due to an increase in the outside air temperature, the value of the electromotive force acquired by the processing device in the acquisition step (the value V1 of the electromotive force before correction) is added with the electromotive force corresponding to the temperature difference due to the fluctuation of the outside air temperature (= S × (T Ａ − T Ａ０ )).

[0011] As a result, the value of the electromotive force not affected by the fluctuation of the outside air temperature (the value V of the electromotive force after correction ２ ) can be obtained.

[0012] As a result, the temperature change of the object can be accurately detected.

[0013] The present invention [2] includes the detection system of [1] above, in which the thermoelectric conversion element has a first thermoelectric conversion member having a first Seebeck coefficient and a second thermoelectric conversion member having a second Seebeck coefficient different from the first Seebeck coefficient and connected to the first thermoelectric conversion member, and the value S of the electromotive force per 1°C of temperature difference of the thermoelectric conversion element is calculated by the following calculation formula.

[0014] Calculation formula: S = |S １ − S ２ | × n (In the above calculation formula, S １ represents the first Seebeck coefficient. S ２(where n represents the second Seebeck coefficient; n represents the number of cell structures consisting of one first thermoelectric conversion member and one second thermoelectric conversion member.)

[0015] In this configuration, the first Seebeck coefficient is determined during the manufacturing of the first thermoelectric conversion component. The second Seebeck coefficient is determined during the manufacturing of the second thermoelectric conversion component. The number of cell structures is determined during the manufacturing of the thermoelectric conversion element.

[0016] Therefore, the value of the electromotive force per 1°C temperature difference of the thermoelectric conversion element 2 can be set during the manufacturing of the thermoelectric conversion element.

[0017] The present invention [3] includes the detection system of [1] or [2] above, wherein the value S of the electromotive force per 1°C temperature difference of the thermoelectric conversion element is the ratio of the measured change in the electromotive force to the measured change in the temperature difference.

[0018] With this configuration, the value S of the electromotive force per 1°C temperature difference of the thermoelectric conversion element can be set based on the measured change in electromotive force in response to the change in temperature difference.

[0019] The present invention [4] includes any one of the detection systems described in [1] to [3] above, wherein the thermoelectric conversion element comprises an insulating material having a predetermined thickness, and a thermoelectric conversion member disposed inside the insulating material and having a predetermined length in the thickness direction of the insulating material, and generating an electromotive force due to a temperature difference in the thickness direction of the insulating material, wherein the temperature difference is the difference between the temperature of one side of the insulating material in the thickness direction and the temperature of the other side of the insulating material in the thickness direction.

[0020] This configuration comprises an insulating material having a predetermined thickness and a thermoelectric conversion member. The thermoelectric conversion member has a portion that is disposed inside the insulating material. The portion disposed inside the insulating material has a predetermined length in the thickness direction.

[0021] Therefore, thermoelectric conversion components can generate electromotive force by utilizing the temperature difference in the thickness direction of the insulating material.

[0022] The present invention [5] includes the detection system of [4] above, wherein the thermoelectric conversion member is thread-like.

[0023] According to the detection system of the present invention, temperature changes of the target can be accurately detected.

[0024] Figure 1 shows a block diagram of a detection system as one embodiment of the present invention. Figure 2 shows a pipe insulation structure as an example of an application of the detection system shown in Figure 1. Figure 3 is a perspective view of the insulation material shown in Figure 2. Figure 4 is a cross-sectional view taken along line A-A of the insulation material shown in Figure 3. Figure 5 is a flowchart of the detection process performed by the processing device shown in Figure 1. Figure 6 is a perspective view showing a first modified example of the thermoelectric conversion element. Figure 7 is a cross-sectional view showing a second modified example of the thermoelectric conversion element. Figure 8 is a cross-sectional view showing a third modified example of the thermoelectric conversion element. Figure 9 is a cross-sectional view showing a fourth modified example of the thermoelectric conversion element.

[0025] 1. Detection System As shown in Figure 1, the detection system 1 comprises a thermoelectric conversion element 2, a conversion circuit 3, a transmitting module 4, a receiving module 5, and a processing unit 6. The detection system 1 detects temperature changes of an object. The object is not limited. As shown in Figure 2, an example of an object is the insulation material 100 of a pipe P. The insulation material 100 covers the pipe P. The insulation material 100 may be covered by a metal exterior member C. As shown in Figure 3, the insulation material 100 has, for example, a cylindrical shape.

[0026] (1) Thermoelectric Conversion Elements In this embodiment, the detection system 1 includes a plurality of thermoelectric conversion elements 2A, 2B, and 2C. The thermoelectric conversion elements 2A, 2B, and 2C are independent of each other. The thermoelectric conversion elements 2A, 2B, and 2C are arranged at intervals from each other. The thermoelectric conversion elements 2A, 2B, and 2C are arranged, for example, in the direction in which the pipe P extends. Each of the thermoelectric conversion elements 2A, 2B, and 2C utilizes a portion of the insulation material 100 of the pipe P.

[0027] More specifically, as shown in Figure 4, the thermoelectric conversion element 2A includes a thermal insulation material 100 as an example of an insulating material, and a thermoelectric conversion member 21. In other words, the thermoelectric conversion element 2A utilizes a portion of the thermal insulation material 100 of the piping P as an insulating material.

[0028] (1-1) Insulation material The insulation material 100 has a predetermined thickness. The insulation material 100 has one surface S1 and the other surface S2 in the thickness direction of the insulation material 100. In the following description, the thickness direction of the insulation material 100 will be referred to as the "thickness direction". The one surface S1 and the other surface S2 extend in the surface direction. The surface direction intersects with the thickness direction. Preferably, the surface direction is perpendicular to the thickness direction.

[0029] The thermal insulation material 100 has both insulating properties and thermal insulation properties. The insulating properties of the thermal insulation material 100 can be defined by the resistance value of the thermal insulation material 100. The thermal insulation properties of the thermal insulation material 100 can be defined by the thermal conductivity of the thermal insulation material 100.

[0030] The resistance value of the thermal insulation material 100 is not limited as long as it prevents short circuits in the thermoelectric conversion member 21.

[0031] The thermal conductivity of the insulating material 100 is, for example, 1 W / m·K or less, preferably 0.5 W / m·K or less. When the thermal conductivity of the insulating material 100 is below the above upper limit, a temperature difference can be secured in the thickness direction, and the resulting electromotive force can be increased.

[0032] The lower limit of the thermal conductivity of the insulation material 100 is not limited. The thermal conductivity of the insulation material 100 is, for example, 0.01 W / m·K or higher.

[0033] Examples of materials for the thermal insulation material 100 include glass wool, rock wool, calcium silicate, polystyrene, polyethylene, urethane resin, melamine resin, phenolic resin, foamed glass, perlite, cellulose fiber, alumina fiber, ceramic fiber, carbon fiber, fumed silica, and alkali earth silicate. Preferably, the thermal insulation material 100 is glass wool, rock wool, and calcium silicate, and more preferably glass wool.

[0034] The thermal insulation material 100 may consist of only one of the materials described above. The thermal insulation material 100 may contain two or more of the materials described above. The thermal insulation material 100 includes at least one of glass wool, rock wool, and calcium silicate. When the thermal insulation material 100 includes at least one of glass wool, rock wool, and calcium silicate, the thermal insulation performance of the thermal insulation material 100 can be improved. This makes it possible to secure a temperature difference in the thickness direction and increase the electromotive force obtained. Preferably, the thermal insulation material 100 includes a layer made of at least one of glass wool, rock wool, and calcium silicate. More preferably, the thermal insulation material 100 consists of glass wool.

[0035] The thickness of the thermal insulation material 100 is, for example, 10 mm or more, preferably 30 mm or more. If the thickness of the thermal insulation material 100 is greater than or equal to the above lower limit, a temperature difference can be secured in the thickness direction, and the resulting electromotive force can be increased.

[0036] There is no upper limit to the thickness of the insulation material 100. The thickness of the insulation material 100 is, for example, 300 mm or less.

[0037] (1-2) Thermoelectric Conversion Member The thermoelectric conversion member 21 generates an electromotive force due to a temperature difference in the thickness direction. As a result, the thermoelectric conversion element 2 generates an electromotive force due to a temperature difference. The temperature difference is, for example, the difference between the temperature of one side of the insulating material 100 in the thickness direction and the temperature of the other side of the insulating material 100 in the thickness direction. More specifically, the temperature difference is the temperature difference between the temperature of the fluid flowing in the pipe P and the ambient temperature. The temperature of the fluid flowing in the pipe P can be measured by a temperature sensor attached to the pipe P. The thermoelectric conversion member 21 has P-type portions 211A, 211B as an example of a plurality of first thermoelectric conversion members, and N-type portions 212A, 212B as an example of a plurality of second thermoelectric conversion members. In other words, the thermoelectric conversion element 2 has P-type portions 211A, 211B as an example of a first thermoelectric conversion member, and N-type portions 212A, 212B as an example of a second thermoelectric conversion member.

[0038] The P-type portion 211A behaves as a P-type semiconductor. The P-type portion 211A has a first Seebeck coefficient S１ The P-shaped portion 211A extends in the thickness direction. In this embodiment, the P-shaped portion 211A penetrates the thermal insulation material 100. The P-shaped portion 211A has one end 2111A, the other end 2112A, and a main body portion 2113A. The one end 2111A is located outside the thermal insulation material 100. The one end 2111A is located on one surface S1 of the thermal insulation material 100. The other end 2112A is located outside the thermal insulation material 100. The other end 2112A is located on the other surface S2 of the thermal insulation material 100. The main body portion 2113A is located between the one end 2111A and the other end 2112A. The main body portion 2113A is located inside the thermal insulation material 100. In other words, at least a part of the thermoelectric conversion member 21 (the main body portion 2113A) is located inside the thermal insulation material 100. The main body portion 2113A has the same length in the thickness direction as the thickness of the heat insulating material 100. In other words, the thermoelectric conversion member 21 has a predetermined length in the thickness direction. Note that the main body portion 2113A does not have to extend along the thickness direction. The main body portion 2113A may be inclined with respect to the thickness direction.

[0039] The N-type portion 212A behaves as an N-type semiconductor. The N-type portion 212A has a second Seebeck coefficient S ２ It has the second Seebeck coefficient S ２ This is the first Seebeck coefficient S １ This differs from the previous one. The N-shaped portion 212A extends in the thickness direction. In this embodiment, the N-shaped portion 212A penetrates the thermal insulation material 100. The N-shaped portion 212A has one end 2121A, the other end 2122A, and a main body portion 2123A. The one end 2121A is located outside the thermal insulation material 100. The one end 2121A is located on one surface S1 of the thermal insulation material 100. The other end 2122A is located outside the thermal insulation material 100. The other end 2122A is located on the other surface S2 of the thermal insulation material 100. The main body portion 2123A is located between the one end 2121A and the other end 2122A. The main body portion 2123A is located inside the thermal insulation material 100. The main body portion 2123A has the same length as the thickness of the thermal insulation material 100 in the thickness direction.

[0040] The N-type portion 212A is then connected to the P-type portion 211A. More specifically, one end 2121A of the N-type portion 212A is electrically connected to one end 2111A of the P-type portion 211A. As a result, one cell structure 21A of the π-type thermoelectric conversion element is formed from one P-type portion 211A and one N-type portion 212A. In other words, the cell structure A consists of one P-type portion 211A and one N-type portion 212A. The connection portion between the P-type portion 211A and the N-type portion 212A is placed on the surface S1 of the thermal insulation material 100.

[0041] Furthermore, similar to cell structure 21A, one cell structure 21B of the π-type thermoelectric conversion element is formed from one P-type portion 211B and one N-type portion 212B. In other words, cell structure B consists of one P-type portion 211B and one N-type portion 212B. The connection portion between the P-type portion 211B and the N-type portion 212B is placed on the surface S1 of the thermal insulation material 100.

[0042] Then, the other end 2122A of the N-type portion 212A is electrically connected to the other end 2112B of the P-type portion 211B. This connects the cell structure 21A and the cell structure 21B in series. The connection portion between the N-type portion 212A and the P-type portion 212B is placed on the surface S2 of the thermal insulation material 100.

[0043] In this embodiment, the thermoelectric conversion member 21 is thread-like. The thermoelectric conversion member 21 is sewn into the heat insulating material 100.

[0044] The diameter of the thermoelectric conversion member 21 is, for example, 150 μm or more, preferably 300 μm or more. If the diameter of the thermoelectric conversion member 21 is greater than or equal to the above lower limit, the electromotive force of the thermoelectric conversion member 21 can be increased.

[0045] The "diameter of the thermoelectric conversion member 21" refers to the minimum length of the thermoelectric conversion member 21 in the direction perpendicular to the direction in which the thermoelectric conversion member 21 extends (the radial direction of the thermoelectric conversion member 21). Specifically, if the cross-section of the thermoelectric conversion member 21 in the radial direction is circular, the "diameter of the thermoelectric conversion member 21" refers to the diameter of the circle. If the cross-section of the thermoelectric conversion member 21 in the radial direction is elliptical, the "diameter of the thermoelectric conversion member 21" refers to the length of the minor axis of the ellipse. If the thermoelectric conversion member 21 is ribbon-shaped, the "diameter of the thermoelectric conversion member 21" refers to the thickness of the thermoelectric conversion member 21.

[0046] The diameter of the thermoelectric conversion member 21 is, for example, 3000 μm or less, preferably 1500 μm or less, and more preferably 1000 μm or less. If the diameter of the thermoelectric conversion member 21 is below the above upper limit, the decrease in the thermal insulation performance of the thermal insulation material 100 can be suppressed.

[0047] The thermoelectric conversion member 21 contains a conductive material, a binder, and, if necessary, a dopant.

[0048] The conductive material has conductivity. The conductive material imparts conductivity to the thermoelectric conversion member 21. Examples of conductive materials include semiconductor materials, carbon materials, and conductive polymers.

[0049] Examples of semiconductor materials include bismuth (Bi), tellurium (Te), antimony (Sb), cobalt (Co), zinc (Zn), silicon (Si), germanium (Ge), iridium (Ir), lead (Pb), and their alloys, skutterudite, and constantan. While semiconductor materials may contain metallic elements, their crystal structure or the combination of elements in the alloy can result in higher resistance values ​​than metals, thus behaving as semiconductors. Semiconductor materials may also be semiconductor whiskers.

[0050] Examples of carbon materials include carbon nanotubes, carbon nanofibers, graphene, graphene nanoribbons, and fullerene nanowhiskers.

[0051] Examples of conductive polymers include polyacetylene, poly(p-phenylenevinylene), polypyrrole, polythiophene, polyaniline, poly(p-phenylene sulfide), a composite of poly(3,4-ethylenedioxythiophene) and polystyrene sulfonic acid (PEDOT: PSS), a composite of poly(3,4-ethylenedioxythiophene) and polypropylsulfonic acid methylsiloxane (PEDOT: PSiPS), and a composite of poly(3,4-ethylenedioxythiophene) and p-toluenesulfonic acid (PEDOT: Tos).

[0052] Preferably, the conductive material is a carbon material, and more preferably, carbon nanotubes. In other words, the thermoelectric conversion member 21 preferably contains carbon nanotubes, a binder, and optionally, a dopant. When the conductive material is carbon nanotubes, the thermoelectric conversion member 21 can be efficiently manufactured by utilizing the electrical properties of carbon nanotubes as a P-type semiconductor.

[0053] The proportion of conductive material in the thermoelectric conversion member 21 is, for example, 30% by mass or more, preferably 40% by mass or more, and more preferably 50% by mass or more. If the proportion of conductive material is above the above lower limit, the conductivity of the thermoelectric conversion member 21 can be ensured.

[0054] The proportion of conductive material in the thermoelectric conversion member 21 is, for example, 70% by mass or less, preferably 60% by mass or less. When the proportion of conductive material is below the above upper limit, the proportion of binder can be ensured, and the tensile strength of the thermoelectric conversion member 21 can be ensured.

[0055] The proportion of conductive material in the thermoelectric conversion member 21 is, for example, 40 parts by mass or more, preferably 60 parts by mass or more, per 100 parts by mass of binder. If the proportion of conductive material is above the above lower limit, the conductivity of the thermoelectric conversion member 21 can be ensured.

[0056] The proportion of conductive material in the thermoelectric conversion member 21 is, for example, 250 parts by mass or less, preferably 150 parts by mass or less, per 100 parts by mass of binder. When the proportion of conductive material is below the above upper limit, the proportion of binder can be maintained and the tensile strength of the thermoelectric conversion member 21 can be ensured.

[0057] The binder binds the conductive material. If the conductive material is carbon nanotubes, the binder binds the carbon nanotubes. Examples of binders include insulating resins and conductive resins.

[0058] Examples of insulating resins include polyethylene glycol, epoxy resin, acrylic resin, urethane resin, polystyrene resin, polyvinyl resin, and sodium carboxymethylcellulose (CMC-Na). Examples of polyvinyl resins include polyvinyl chloride, polyvinylpyrrolidone, polyvinyl alcohol, and polyvinyl acetate.

[0059] Examples of conductive resins include polyacetylene, poly(p-phenylenevinylene), polypyrrole, polythiophene, polyaniline, poly(p-phenylene sulfide), and poly(3,4-ethylenedioxythiophene).

[0060] Preferably, the binder is an insulating resin, and more preferably, polyethylene glycol.

[0061] The proportion of binder in the thermoelectric conversion member 21 is, for example, 30% by mass or more, preferably 40% by mass or more. If the proportion of binder is above the lower limit, the tensile strength of the thermoelectric conversion member 21 can be ensured.

[0062] The proportion of binder in the thermoelectric conversion member 21 is, for example, 70% by mass or less, preferably 60% by mass or less. When the proportion of binder is below the above upper limit, the proportion of conductive material can be ensured, and the conductivity of the thermoelectric conversion member 21 can be ensured.

[0063] The proportion of binder in the thermoelectric conversion member 21 is, for example, 40 parts by mass or more, preferably 60 parts by mass or more, per 100 parts by mass of conductive material. If the proportion of binder is above the above lower limit, the tensile strength of the thermoelectric conversion member 21 can be ensured.

[0064] The proportion of binder in the thermoelectric conversion member 21 is, for example, 250 parts by mass or less, preferably 150 parts by mass or less, per 100 parts by mass of conductive resin. When the proportion of binder is below the above upper limit, the proportion of conductive material can be ensured, and the conductivity of the thermoelectric conversion member 21 can be ensured.

[0065] The dopant imparts semiconductor electrical properties to the thermoelectric conversion member 21. Examples of dopants include P-type dopants and N-type dopants. The P-type dopant imparts P-type semiconductor electrical properties to the thermoelectric conversion member 21. Note that if the conductive material is carbon nanotubes, the thermoelectric conversion member 21 does not need to contain a P-type dopant because carbon nanotubes have P-type semiconductor electrical properties. The N-type dopant imparts N-type semiconductor electrical properties to the thermoelectric conversion member 21. An example of an N-type dopant is 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF). ６), polyethyleneimine (PEI), ethylenediaminetetrakis(propoxylate-block-ethoxylate) tetrol (trade name: Tetronic® 1107), reduced benzyl viologen (reduced BV), diphenylphosphine (dpp), 1,2-bis(diphenylphosphino)ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp), 1,4-bis(diphenylphosphino)butane (dppb), bis(diphenylphosphinomethyl)phenylphosphine (dppp), bis(diphenylphosphinoethyl)phenylphosphine (ppmdp), bis[(diphenylphosphinomethyl)phenylphosphino]methane (dppmpm), triphenylphosphine (tpp), tris(p-fluorophenyl)phosphine (F-tpp), tris(p-chlorophenyl)phosphine (Cl-tpp), tris(p-methoxy) Examples include phenyl)phosphine (MeO-tpp), tris(4-methoxy-3,5-dimethylphenyl)phosphine (tmdp), indole (Id), polyvinylpyrrole (PVPy), polyvinylpyrrolidone (PVP), 1,3-dimethyl-2-(o-methoxyphenyl)benzimidazole (o-MeO-DMBI), hydrazine monohydrate (HH), phenylhydrazine (MPH), 1,2-diphenylhydrazine (DPH), diazabicycloundecene (DBU), 1,5,7-triazabicyclo[4.4.0]deca-5-ene (TBD), and 7-methyl-1,5,7-triazabicyclo[4.4.0]deca-5-ene (MTBD). Triphenylphosphine is preferred as the N-type dopant.

[0066] The surface of the thermoelectric conversion member 21 may be coated. In other words, the thermoelectric conversion member 21 may have a core containing a conductive material, a binder, and a dopant, and a coating layer that coats the surface of the core. Examples of materials for the coating layer include resins, carbon fibers, metals, metal oxides, and silicon compounds. Examples of resins include epoxy resins, acrylic resins, urethane resins, fluororesins, polyvinyl alcohol, ethylene vinyl alcohol, polybutylene terephthalate, polyamides, polyimides, polyvinyl acetals, polysilsesquioxanes, polysilazanes, and parylenes. Examples of carbon fibers include carbon nanofibers. Examples of metals include aluminum and chromium. Examples of metal oxides include smectite, indium tin oxide (ITO), indium zinc oxide (IZO), aluminum zinc oxide (AZO), and zinc tin oxide (ZTO). Examples of silicon compounds include silica nanoparticles, silicon dioxide, and silicon nitride. The coating layer improves the strength and wear resistance of the thermoelectric conversion member 21. Furthermore, the coating layer suppresses the deterioration of the thermoelectric conversion member 21 due to oxygen and moisture.

[0067] Note that thermoelectric elements 2B and 2C have the same structure as thermoelectric element 2A. Therefore, the explanation of thermoelectric elements 2B and 2C is omitted.

[0068] (2) Conversion Circuit As shown in the diagram 1, the conversion circuit 3 converts the electromotive force generated in each of the thermoelectric conversion elements 2A, 2B, and 2C into an electrical signal. More specifically, the conversion circuit 3 converts the electromotive force of each of the thermoelectric conversion elements 2A, 2B, and 2C into a digital signal. The conversion circuit 3 is electrically connected to each of the thermoelectric conversion elements 2A, 2B, and 2C. The conversion circuit 3 includes an AFE (analog front-end) circuit and an analog-to-digital conversion circuit. The conversion circuit 3 adjusts the electromotive force of each of the thermoelectric conversion elements 2A, 2B, and 2C by the AFE circuit and converts it into a digital signal by the analog-to-digital conversion circuit.

[0069] (3) Transmitting Module The transmitting module 4 transmits the electrical signal converted by the conversion circuit 3. The transmitting module 4 has at least a transmitting antenna. The conversion circuit 3 and the transmitting module 4 may be mounted on the transmitter 10.

[0070] (4) Receiving module The receiving module 5 receives electrical signals transmitted by the transmitting module 4. The receiving module 5 has at least a receiving antenna. The communication standard between the transmitting module 4 and the receiving module 5 is not limited.

[0071] (5) Processing Unit The processing unit 6 performs a detection process (see Figure 5) described later based on the electrical signal received by the receiving module 5. The processing unit 6 is not limited as long as it can perform the detection process described later. The processing unit 6 includes, for example, a processor and memory. The processing unit 6 may be installed in a personal computer together with the receiving module 5.

[0072] 2. Detailed Detection Process As shown in Figure 5, the processing device 6 performs a process to detect the temperature of the target (detection process). In this embodiment, the processing device 6 detects a decrease in the temperature difference (i.e., thermal insulation performance) between the temperature of the thermal insulation material 100 on the side of the pipe P and the temperature of the thermal insulation material 100 on the opposite side of the pipe P.

[0073] For example, if the insulation material 100 gets wet, its thermal insulation performance decreases. When the thermal insulation performance of the insulation material 100 decreases, the temperature difference between the insulation material 100 on the side of the pipe P and the insulation material 100 on the opposite side of the pipe P decreases. As a result, the electromotive force of the thermoelectric conversion element 2 decreases.

[0074] Furthermore, even if the insulation material 100 is not wet, if water penetrates between the insulation material 100 and the pipe P, the surface temperature of the pipe P will decrease due to the penetrated water. When the surface temperature of the pipe P decreases, the temperature difference between the insulation material 100 on the pipe P side and the insulation material 100 on the opposite side of the pipe P decreases. As a result, the electromotive force of the thermoelectric conversion element 2 decreases.

[0075] The detection system 1 detects the intrusion of water into the insulating structure of the piping P by detecting a decrease in the electromotive force of the thermoelectric conversion element 2.

[0076] The detection process includes an acquisition step (S1) and correction steps (S2 to S4). In other words, the processing device 6 performs the acquisition step (S1) and the correction steps (S2 to S4).

[0077] (1) Acquisition step In the acquisition step (S1), the processing unit 6 acquires the value of the electromotive force generated in the thermoelectric conversion element 2. Specifically, in the acquisition step (S1), the processing unit 6 acquires the value of the electromotive force (measured value) generated in each of the thermoelectric conversion elements 2A, 2B, and 2C based on the electrical signal received by the receiving module 5 (see Figure 1).

[0078] Here, the electromotive force value (measured value) acquired by the processing device 6 in the acquisition step (S1) fluctuates depending on the temperature difference between the temperature on one side of the insulation material 100 in the thickness direction (specifically, the ambient temperature) and the temperature on the other side of the insulation material 100 in the thickness direction (specifically, the temperature of the fluid flowing inside the pipe P). For example, even if the temperature of the fluid flowing inside the pipe P is constant and the insulation performance of the insulation material 100 has not deteriorated, the electromotive force of the thermoelectric conversion member 2 may decrease due to fluctuations in ambient temperature. In that case, it may become difficult to accurately detect the intrusion of water into the insulation structure of the pipe P.

[0079] (2) Correction step In the correction step, if the temperature difference increases due to the rise in ambient temperature (S2: YES), the processing device 6 corrects the value of the electromotive force (measured value) acquired in the acquisition step (S1) using the correction formula (1) below (S3). If the temperature difference decreases due to the rise in ambient temperature (S2: NO), the processing device 6 corrects the value of the electromotive force (measured value) acquired in the acquisition step (S1) using the correction formula (2) below (S4).

[0080] Correction formula (1): V ２ = V １ -S × (T Ａ -T Ａ０ ) Correction formula (2): V ２ = V １ +S × (T Ａ -T Ａ０ ) In the above correction formula (1) and the above correction formula (2), V １This indicates the value of the electromotive force before correction, i.e., the value of the electromotive force acquired by the processing unit 6 in the acquisition step (S1) (measured value). ２ This indicates the corrected electromotive force value. Ａ This indicates the actual measured value of the outside temperature.

[0081] T Ａ０ This indicates the reference value for outside temperature. Reference value for outside temperature T Ａ０ This may be pre-stored in the memory of the processing unit 6. The initial outside temperature when the insulation material 100 was installed on the piping P is set to the reference value T of the outside temperature. Ａ０ That is also acceptable.

[0082] In the insulated structure of pipe P, the ambient temperature T is lower than the temperature of the fluid flowing inside pipe P. Ａ０ When the temperature is high, the temperature difference between the temperature on one side of the insulation material 100 in the thickness direction and the temperature on the other side of the insulation material 100 in the thickness direction increases due to the rise in ambient temperature. In other words, in the insulation structure of the pipe P, "when the temperature difference increases due to the rise in ambient temperature" means that the ambient temperature is higher than the temperature of the fluid flowing inside the pipe P. Ａ０ This is the case when the value is high (S2: YES).

[0083] Furthermore, in the thermal insulation structure of the pipe P, the ambient temperature T is higher than the temperature of the fluid flowing inside the pipe P. Ａ０ When the ambient temperature is low, the temperature difference between the temperature on one side of the insulation material 100 in the thickness direction and the temperature on the other side of the insulation material 100 in the thickness direction decreases as the ambient temperature rises. In other words, in the insulation structure of the pipe P, "when the temperature difference decreases as the ambient temperature rises" means that the ambient temperature is lower than the temperature of the fluid flowing inside the pipe P. Ａ０ This is the case when the value is low (S2: NO).

[0084] S represents the electromotive force value per 1°C temperature difference of the thermoelectric conversion element 2. The electromotive force value S per 1°C temperature difference of the thermoelectric conversion element 2 can be calculated, for example, by the following formula.

[0085] Calculation formula: S=|S １ -S ２ | × n In the above calculation formula, S １ This shows the Seebeck coefficient (first Seebeck coefficient) of the P-type portions 211A and 211B. ２This represents the Seebeck coefficient (second Seebeck coefficient) of the N-type portions 212A and 211B. n represents the number of cell structures 21A and 21B.

[0086] The Seebeck coefficients of the P-type sections 211A and 211B, the Seebeck coefficients of the N-type sections 212A and 212B, and the number of cell structures 21A and 21B are determined during the manufacturing of the thermoelectric conversion element 2. Therefore, the value S of the electromotive force per 1°C temperature difference of the thermoelectric conversion element 2 is also determined during the manufacturing of the thermoelectric conversion element 2.

[0087] In the correction formula (1) described above, the measured value of the electromotive force acquired by the processing device 6 in the acquisition step (S1) (the value of the electromotive force before correction V) １ ) From the standard value T of the outside temperature Ａ０ and the measured value of the outside temperature T Ａ The electromotive force equivalent to the difference between (= S × (T)) Ａ -T Ａ０ Subtracting the value of the electromotive force that is not affected by fluctuations in outside temperature (corrected electromotive force value V) ２ ) can be obtained.

[0088] Furthermore, in the correction formula (2) described above, the measured value of the electromotive force acquired by the processing device 6 in the acquisition step (S1) (the value of the electromotive force before correction V) １ ) with the standard value T for outside temperature Ａ０ and the measured value of the outside temperature T Ａ The electromotive force equivalent to the difference between (= S × (T)) Ａ -T Ａ０ Add the values ​​of ()) to obtain the electromotive force value that is not affected by fluctuations in ambient temperature (corrected electromotive force value V). ２ ) can be obtained.

[0089] While the detection system 1 is running (S3: NO), the processing unit 6 repeats the acquisition step (S1) and the correction step (S2).

[0090] 3. Effects (1) The detection system 1 comprises a thermoelectric conversion element 2 and a processing device 6, as shown in Figure 1. The processing device 6, as shown in Figure 5, detects a reference value T of the ambient temperature which is higher than the temperature of the fluid flowing in the pipe P. Ａ０If the temperature difference is high (i.e., the temperature difference increases due to the rise in ambient temperature, S2: YES), the measured value of the electromotive force acquired in the acquisition step (S1) is corrected using the correction formula (1) below (S3). If the temperature difference decreases due to the rise in ambient temperature (S2: NO), a correction step is performed in which the value of the electromotive force acquired in the acquisition step is corrected using the correction formula (2) below.

[0091] Correction formula (1): V ２ = V １ -S × (T Ａ -T Ａ０ ) Correction formula (2): V ２ = V １ +S × (T Ａ -T Ａ０ ) (In the above correction formula (1) and the above correction formula (2), V １ V indicates the value of the electromotive force before correction. ２ T indicates the corrected value of the electromotive force. S indicates the value of the electromotive force per 1°C temperature difference of the thermoelectric conversion element. Ａ This indicates the measured value of the outside temperature. Ａ０ (This indicates the standard value for outside temperature.)

[0092] Therefore, if the temperature difference increases due to the rise in ambient temperature, the electromotive force value acquired by the processing unit in the acquisition step (the electromotive force value before correction V) １ From ), the electromotive force (= S × (T) corresponds to the temperature difference due to fluctuations in the outside temperature. Ａ -T Ａ０ Subtracting the value of the electromotive force that is not affected by fluctuations in outside temperature (corrected electromotive force value V) ２ ) can be obtained.

[0093] Furthermore, if the temperature difference decreases due to a rise in the outside temperature, the electromotive force value acquired by the processing unit in the acquisition step (the electromotive force value before correction V) １ ) and the electromotive force (= S × (T) corresponding to the temperature difference due to fluctuations in the outside temperature. Ａ -T Ａ０ Add the values ​​of ()) to obtain the electromotive force value that is not affected by fluctuations in ambient temperature (corrected electromotive force value V). ２ ) can be obtained.

[0094] As a result, temperature changes in the target can be accurately detected.

[0095] (2) According to the detection system 1, the value S of the electromotive force per 1°C temperature difference of the thermoelectric conversion element 2 is calculated by the following formula.

[0096] Calculation formula: S=|S １ -S ２ | × n (In the above calculation formula, S １ This shows the Seebeck coefficients of the P-type portions 211A and 211B. ２ (where n represents the Seebeck coefficients of the N-type portions 212A and 212B, and n represents the number of cell structures 21A and 21B.)

[0097] Seebeck coefficient S of P-type portions 211A and 211B １ Seebeck coefficient S of N-type portions 212A and 212B ２ The number of cell structures 21A and 21B is determined during the manufacturing of the thermoelectric conversion element 2.

[0098] Therefore, the value S of the electromotive force per 1°C temperature difference of the thermoelectric conversion element 2 can be set during the manufacturing of the thermoelectric conversion element 2.

[0099] (3) According to the detection system 1, as shown in Figure 3, the thermoelectric conversion element 2 comprises a thermal insulation material 100 having a predetermined thickness and a thermoelectric conversion member 21. The thermoelectric conversion member 21 has a portion that is placed inside the thermal insulation material 100. The portion that is placed inside the thermal insulation material 100 has a predetermined length in the thickness direction.

[0100] Therefore, the thermoelectric conversion member 21 can generate electromotive force by utilizing the temperature difference in the thickness direction of the insulating material 100.

[0101] 4. Modified Examples Modified examples will be described. In the modified examples, the same reference numerals are used for components similar to those in the embodiments described above, and their descriptions are omitted.

[0102] (1) The detection system 1 is not limited to the insulation material 100 of the piping P. Examples of objects that the detection system 1 can detect include insulation materials for the roofs and exterior walls of houses, vacuum insulation materials, insulation materials for cooler boxes, insulation materials for liquefied gas tanks, and insulation materials for fermentation culture tanks.

[0103] (2) The value S of the electromotive force per 1°C temperature difference of the thermoelectric element 2 may be the ratio of the "measured change in electromotive force" to the "measured change in temperature difference". For example, after the thermoelectric element 2 is manufactured, the "change in electromotive force with respect to the change in temperature difference" of the thermoelectric element 2 may be measured, and the value S of the electromotive force per 1°C temperature difference of the thermoelectric element 2 may be set. Alternatively, for example, if the insulation material 100 of the pipe P described above is used, the "change in electromotive force with respect to the change in temperature difference" of the thermoelectric element 2 may be measured with the insulation material 100 having the thermoelectric element 2 attached to the pipe P, and the value S of the electromotive force per 1°C temperature difference of the thermoelectric element 2 may be set.

[0104] According to this modified example, the value S of the electromotive force per 1°C temperature difference of the thermoelectric conversion element 2 can be set based on the measured change in electromotive force in response to the change in temperature difference.

[0105] (3) As shown in Figure 6, the detection system 1 may have a P-type thermoelectric conversion member 200A consisting only of a P-type portion 211 and an N-type thermoelectric conversion member 200B consisting only of an N-type portion 212. A part of the P-type thermoelectric conversion member 200A and a part of the N-type thermoelectric conversion member 200B may be electrically connected by a conductive paste 213 or the like.

[0106] In this case, the P-type thermoelectric conversion member 200A and the N-type thermoelectric conversion member 200B may each be thread-like and sewn into the insulation material 100.

[0107] The detection system 1 may also include a metal wire instead of the P-type thermoelectric conversion member 200A. In other words, the detection system 1 may have a cell structure consisting of an N-type thermoelectric conversion member and a metal wire electrically connected to the N-type thermoelectric conversion member.

[0108] Furthermore, the detection system 1 may be equipped with a metal wire instead of the N-type thermoelectric conversion member 200B. In other words, the detection system 1 may have a cell structure consisting of a P-type thermoelectric conversion member and a metal wire electrically connected to the P-type thermoelectric conversion member.

[0109] (4) As shown in Figure 7, the thermoelectric conversion element 300 may have cover layers 110A and 110B that cover the connection portion between the P-type portion 211 and the N-type portion 212. The thermoelectric conversion element 300 may consist only of the heat insulating material 100, the thermoelectric conversion member 21, and the cover layers 110A and 110B. As the material for the cover layers 110A and 110B, for example, the material of the heat insulating material 100 described above can be cited. The cover layers 110A and 110B may have a coating layer. As the material for the coating layer, for example, the material of the coating layer of the thermoelectric conversion member 21 described above can be cited.

[0110] Furthermore, as shown in Figure 8, the entire thermoelectric conversion member 21 may be placed inside the thermal insulation material 100. In other words, the thermoelectric conversion member 21 may consist only of the portion placed inside the thermal insulation material 100.

[0111] (5) The insulating material is not limited to the heat insulating material 100 described above. As shown in Figure 9, the thermoelectric conversion element 400 may have a resin body 401 as an example of an insulating material and a thermoelectric conversion member 21. In this case, the thermoelectric conversion element 400 may be embedded in the heat insulating material 100 described above. Examples of materials for the resin body 401 include thermoplastic resins and thermosetting resins.

[0112] Examples of thermoplastic resins include polyvinyl chloride (PVC), polystyrene (PS), styrene-based resins (HIPS, SAN, ABS), acrylic resin (PMMA), polyethylene (PE), polypropylene (PP), polycarbonate (PC), modified polyetherphenyl (m-PPE), polyacetal (POM), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyamide (PA), polyarylate (PAR), polysulfone (PSU), polyethersulfone (PES), thermoplastic polyimide (TPI, PEI, PAI), polyphenylene sulfide (PPS), polyetheretherketone (PEEK), liquid crystal polymer (LCP), and fluororesins (PTFE, PFA, PVDF, ETFE).

[0113] Examples of the thermosetting resin include an epoxy resin (EP), a silicone resin (SI), a diallyl phthalate resin (PDAP), a phenol resin (PF), an unsaturated polyester resin (UP), a polyimide resin (PI), a polyurethane resin (PUR), a melamine resin (MF), a urea resin (UF), and a thermosetting acrylic resin (PAR).

[0114] As the material of the resin body 401, preferably, a thermosetting resin, more preferably, an epoxy resin is exemplified.

[0115] In the correction step, when the reference value T of the outside air temperature is higher than the temperature of the fluid flowing in the pipe P (that is, when the temperature difference increases due to the rise of the outside air temperature, S2: YES), the electromotive force corresponding to the difference between the change in the outside air temperature and the change in the temperature of the pipe P may be subtracted from the value of the electromotive force acquired by the processing device 6 in the acquisition step (S1) (the value of the electromotive force before correction V Ａ０ ). In this case, for example, the value of the electromotive force generated in the thermoelectric conversion element 2 is corrected by the following correction formula (1). １

[0116] Correction formula (1): V ２ = V １ - S × [(T Ａ - T Ａ０ ) - (T Ｂ - T Ｂ０ )] Also, when the reference value T of the outside air temperature is lower than the temperature of the fluid flowing in the pipe P (that is, when the temperature difference decreases due to the rise of the outside air temperature, S2: NO), the electromotive force corresponding to the difference between the change in the outside air temperature and the change in the temperature of the pipe P may be added to the value of the electromotive force acquired by the processing device 6 in the acquisition step (S1) (the value of the electromotive force before correction V Ａ０ ). In this case, for example, the value of the electromotive force generated in the thermoelectric conversion element 2 is corrected by the following correction formula (2). １

[0117] Correction formula (2): V ２ = V １ + S × [(T Ａ - T Ａ０ ) - (T Ｂ - T Ｂ０ )] In the above correction formula (1) and the above correction formula (2), T Ｂ ​​This shows the measured temperature of pipe P. Ｂ０ This indicates the reference temperature for pipe P.

[0118] Measured temperature T of pipe P Ｂ This may be the measured temperature of the surface of pipe P. Alternatively, the measured temperature of the fluid (liquid or gas) flowing inside pipe P may be used as the measured temperature T of pipe P. Ｂ That is also acceptable.

[0119] Reference value T for the temperature of pipe P Ｂ０ This may be pre-stored in the memory of the processing unit 6. The initial temperature of the pipe P after the insulation material 100 has been installed on the pipe P is set to the reference value T of the temperature of the pipe P. Ｂ０ That is also acceptable.

[0120] In this modified example, the ambient temperature T is lower than the temperature of the fluid flowing through the pipe P. Ａ０ If the value is high (i.e., the temperature difference increases due to the rise in ambient temperature, S2: YES), the value of the electromotive force acquired by the processing unit 6 in the acquisition step (S1) (the value of the electromotive force before correction V) １ Subtract the electromotive force corresponding to the difference between the fluctuation in ambient temperature and the fluctuation in the temperature of pipe P from the above.

[0121] Furthermore, the ambient temperature T is lower than the temperature of the fluid flowing through the pipe P. Ａ０ If the value is low (i.e., if the temperature difference decreases due to the rise in ambient temperature, S2: NO), the value of the electromotive force acquired by the processing unit 6 in the acquisition step (S1) (value of the electromotive force before correction V) １ ) is then combined with the electromotive force corresponding to the difference between the fluctuation in ambient temperature and the fluctuation in the temperature of pipe P.

[0122] Therefore, it can detect temperature changes in the target more accurately.

[0123] (7) The same effects and advantages as the embodiments can be obtained with the above-described modifications (1) to (6). Although the above-described invention is provided as an illustrative embodiment of the present invention, this is merely illustrative and should not be interpreted restrictively. Modifications of the present invention that are obvious to those skilled in the art are included in the claims below.

[0124] The detection system of the present invention can be used, for example, to detect temperature changes in insulation material around piping.

[0125] 1 Detection system 2 Thermoelectric conversion element 6 Processing device 21 Thermoelectric conversion member 211A P-type portion (an example of the first thermoelectric conversion member) 212A N-type portion (an example of the second thermoelectric conversion member) 100 Thermal insulation material (an example of an insulating material)

Claims

1. A detection system comprising a thermoelectric conversion element that generates an electromotive force due to a temperature difference and a processing device, wherein the processing device executes an acquisition step of acquiring a value of the electromotive force generated in the thermoelectric conversion element, and a correction step of correcting the value of the electromotive force acquired in the acquisition step by the following correction formula (1) when the temperature difference increases due to an increase in the outside air temperature, and correcting the value of the electromotive force acquired in the acquisition step by the following correction formula (2) when the temperature difference decreases due to an increase in the outside air temperature. Correction formula (1): V ２ = V １ - S × (T Ａ - T Ａ０ ) Correction formula (2): V ２ = V １ + S × (T Ａ - T Ａ０ ) (In the above correction formula (1) and the above correction formula (2), V １ represents the value of the electromotive force before correction. V ２ represents the value of the electromotive force after correction. S represents the value of the electromotive force per 1 °C of the temperature difference of the thermoelectric conversion element. T Ａ represents the measured value of the outside air temperature. T Ａ０ represents the reference value of the outside air temperature.) 2. The detection system according to claim 1, wherein the thermoelectric conversion element comprises a first thermoelectric conversion member having a first Seebeck coefficient, and a second thermoelectric conversion member having a second Seebeck coefficient different from the first Seebeck coefficient and connected to the first thermoelectric conversion member, and the value S of the electromotive force per 1°C temperature difference of the thermoelectric conversion element is calculated by the following formula: Formula: S = |S １ -S ２ | × n (In the above calculation formula, S １ This represents the first Seebeck coefficient. ２ (where n represents the second Seebeck coefficient; n represents the number of cell structures consisting of one first thermoelectric conversion member and one second thermoelectric conversion member.) 3. The detection system according to claim 1, wherein the value S of the electromotive force per 1°C temperature difference of the thermoelectric conversion element is the ratio of the measured change in the electromotive force to the measured change in the temperature difference.

4. The detection system according to any one of claims 1 to 3, wherein the thermoelectric conversion element comprises an insulating material having a predetermined thickness, and a thermoelectric conversion member disposed inside the insulating material and having a predetermined length in the thickness direction of the insulating material, and generating an electromotive force due to a temperature difference in the thickness direction of the insulating material, wherein the temperature difference is the difference between the temperature of one side of the insulating material in the thickness direction and the temperature of the other side of the insulating material in the thickness direction.

5. The detection system according to claim 4, wherein the thermoelectric conversion member is thread-shaped.

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