Specimen deterioration detection device and detection method

Abstract

To reduce proficient skills required for a worker who installs a device for detecting deterioration of a sample.SOLUTION: A sample deterioration detection device 10 comprises: a piezoelectric element 11 for holding a sample 8 between itself and a measurement reference surface 9; a measurement unit 15 for applying a driving voltage to the piezoelectric element 11 and measuring a vibration state of the piezoelectric element 11; and a determination unit 16 for determining deterioration of the sample 8 based on the vibration state.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an apparatus and method for detecting deterioration of a sample such as grease used in a drive part, which is installed in the same environment as a drive part of a circuit breaker or disconnecting switch provided in a power switchgear such as a gas insulated switchgear (GIS). [Background technology]

[0002] Grease has traditionally been used in power switchgear to lubricate and seal the drive parts. When grease is used in the drive parts of rotating equipment such as electric motors, its properties deteriorate due to overheating or the inclusion of foreign matter. For this reason, rotating equipment is periodically shut down to measure grease degradation.

[0003] For example, in the case of power switches such as gas-insulated switchgear (GIS), the operating frequency of drive parts such as circuit breakers and disconnectors is extremely low. Therefore, the grease usage environment is similar to that of static equipment such as transformers and power converters, and the causes of grease degradation are different from overheating or foreign matter contamination. For example, when gas-insulated switchgear that has been in grid operation for a long period of time is shut down for an extended period of time and then restarted, the grease's base oil evaporates, causing the grease to deteriorate and leading to malfunctions in the drive parts. This can result in malfunctions such as an inability to cut off power in the event of an abnormality, or burnout of electrical circuits such as coils used to drive the arc. For this reason, research into grease degradation in power switches such as gas-insulated switchgear is being conducted.

[0004] An example of a device that continuously detects grease deterioration in an electric power switchgear is the detection device described in Patent Document 1. The detection device in Patent Document 1 can continuously and automatically detect grease deterioration. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-197332 Summary of the Invention [Problem to be solved by the invention]

[0006] In the detection device described in Patent Document 1, when installing the detection device in a switchgear, the worker is required to have the skilled experience to carefully and meticulously place the grease in the grease placement area without any gaps or air bubbles remaining. If gaps or air bubbles remain due to the worker's lack of skill, there is a risk of detection errors, and even if the grease is deteriorated, it may not be detected. There is a need to reduce the skilled experience required of workers who install devices that detect grease deterioration in power switchgears.

[0007] An object of the present invention is to reduce the level of skill required of an operator who installs an apparatus for detecting deterioration of a sample. [Means for solving the problem]

[0008] A sample deterioration detection device according to one aspect of the present invention comprises a piezoelectric element that sandwiches a sample between itself and a measurement reference surface, a measurement unit that applies a drive voltage to the piezoelectric element to measure the vibration state of the piezoelectric element, and a judgment unit that judges the deterioration of the sample based on the vibration state.

[0009] A sample deterioration detection method according to one aspect of the present invention includes a clamping step of clamping a sample between a measurement reference surface and a piezoelectric element, a measurement step of applying a drive voltage to the piezoelectric element to measure a vibration state of the piezoelectric element, and a determination step of determining deterioration of the sample based on the vibration state. [Effects of the Invention]

[0010] According to the present invention, the level of skill required of an operator who installs an apparatus for detecting deterioration of a sample can be reduced. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram schematically illustrating a general configuration of a detection device according to a first embodiment. [Figure 2] FIG. 2 is a perspective view showing a state in which the restraint device according to the first embodiment houses a piezoelectric element. [Figure 3] 1A and 1B are diagrams illustrating the structure of a piezoelectric element and a restraint device according to a first embodiment. [Figure 4] FIG. 2 is a circuit diagram of a measurement unit according to the first embodiment. [Figure 5] 4 is a flowchart showing a processing procedure of a detection method according to the first embodiment. [Figure 6] FIG. 4 is a diagram schematically illustrating a general configuration of a detection device according to a second embodiment. [Figure 7] FIG. 10 is a diagram showing a state in which two piezoelectric elements according to a second embodiment are arranged opposite each other. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description and drawings, the same reference numerals will denote the same or similar components, and therefore, redundant descriptions of the same or similar components will be omitted.

[0013] [Summary of the invention] The sample deterioration detection device (hereinafter also simply referred to as the detection device) according to the embodiment of the present invention described below is a device for detecting sample deterioration. The detection device includes a piezoelectric element that sandwiches the sample between itself and a measurement reference surface, a measurement unit that applies a drive voltage to the piezoelectric element to measure the vibration state of the piezoelectric element, and a determination unit that determines sample deterioration based on the vibration state.

[0014] The piezoelectric element can be arranged in a curved state or can be provided on an elastic body.

[0015] The measurement unit can measure the vibration state of each of a reference sample that serves as the basis for judgment and a target sample that is the subject of judgment, and the judgment unit can judge the deterioration of the target sample based on the vibration state measured for the reference sample and the vibration state measured for the target sample.

[0016] The detection device may further include a retainer that keeps the piezoelectric element in a curved state, and may further include an alarm unit that outputs an alarm based on the determination result of the determination unit.

[0017] A detection device according to an embodiment of the present invention is installed in the same environment as a driving part, such as a circuit breaker or disconnecting switch, provided in a power switchgear such as a gas-insulated switchgear (GIS). A sample for which degradation is to be determined is placed inside the detection device. The sample for which degradation is to be determined is the same grease as that used in the driving part, and the detection device detects degradation of the grease placed in the same environment as the driving part.

[0018] For example, when a detection device is installed in a gas-insulated switchgear in system operation, the detection device continuously and automatically detects grease degradation in an insulating gas atmosphere such as SF6, and monitors the degradation status. If the detection device determines that the grease has deteriorated, it transmits information that the grease has deteriorated in the gas-insulated switchgear to a centralized monitoring device (not shown) that centrally monitors the operating status of multiple other power facilities, for example, by wired or wireless communication via a network. The monitor of the centralized monitoring device displays, for example, information that the grease has deteriorated in the gas-insulated switchgear, along with a message urging maintenance of the gas-insulated switchgear with deteriorated grease.

[0019] [First embodiment] Fig. 1 is a diagram showing a schematic configuration of a detection device according to a first embodiment. Fig. 2 is a perspective view showing a state in which a piezoelectric element is housed in a restraint device according to the first embodiment. Fig. 3 is a diagram showing the structure of the piezoelectric element and the restraint device according to the first embodiment. (A) is an exploded side view, (B) is a cross-sectional view, and (C) is a top view.

[0020] In the first embodiment, the detection device 10 determines the deterioration of the sample 8 using one piezoelectric element 11. In the first embodiment, the measurement reference surface 9 can be expressed as the surface of the target device on which the piezoelectric element 11 is installed.

[0021] The detection device 10 according to the first embodiment includes a piezoelectric element 11, a restraint device 12, a measurement unit 15, a determination unit 16, and an alarm unit 17. The measurement unit 15, the determination unit 16, and the alarm unit 17 are connected to each other so that they can communicate data with each other. In the following description, the term "signal" also includes data and information communicated between the measurement unit 15, the determination unit 16, and the alarm unit 17.

[0022] The piezoelectric element 11 sandwiches the sample 8 between itself and the measurement reference surface 9. The measurement reference surface 9 is the surface on which the sample 8 is placed. In this embodiment, the measurement reference surface 9 is the surface of a drive part of a circuit breaker, a disconnector, or the like provided in the gas-insulated switchgear, or the inner surface of a metal pipe that houses a busbar for AC power transmission. In the gas-insulated switchgear, the surfaces of these drive parts and the inner surface of the metal pipe are under an insulating gas atmosphere, such as SF6. In this embodiment, the surface of the drive part of a circuit breaker provided in the gas-insulated switchgear will be described as the measurement reference surface 9, for example. The piezoelectric element 11 and the sample 8 are placed on the surface of the drive part of the circuit breaker. The sample 8 is, for example, grease used in the drive part of the circuit breaker. In this embodiment, the piezoelectric element 11 is kept curved by a retainer 12.

[0023] The restrainer 12 keeps the piezoelectric element 11 in a curved state. When the piezoelectric element 11 is curved, the springiness of the piezoelectric element 11 is enhanced. Springiness refers to the ability to recover from elastic deformation. When the springiness of the piezoelectric element 11 is enhanced, the response current 111 of the piezoelectric element 11, which indicates the vibration state of the piezoelectric element 11, better reflects the lubricity between the sample 8 and the measurement reference surface 9, further improving measurement accuracy.

[0024] In this embodiment, a step 122 is provided on the side wall 121 of the restraint device 12, and a mounting fixture 13 used for attaching to the measurement reference surface 9 is disposed on the step 122. As shown in the figure, it is preferable that at least a portion of the restraint device 12 is open so that the piezoelectric element 11 is exposed to the atmosphere in which it is installed. In the embodiment shown in the figure, the restraint device 12 is U-shaped, with a portion of the side open. The restraint device 12 can be formed using, for example, resin or metal. Any material can be used for the restraint device 12 as long as it is capable of maintaining the piezoelectric element 11 in a curved state.

[0025] For example, a magnet can be used for the mounting fixture 13. As long as it is possible to install the restraint device 12 on the measurement reference surface 9, various mounting methods other than a magnet can be used for the mounting fixture 13, such as installation using adhesive, glue, screws, or external spring force.

[0026] FIG. 4 is a circuit diagram of the measurement unit according to the first embodiment.

[0027] The measuring unit 15 applies a drive voltage to the piezoelectric element 11 and measures the vibration state of the piezoelectric element 11. The drive voltage is a high frequency voltage, and the response current 111 of the piezoelectric element 11 indicates the vibration state of the piezoelectric element 11.

[0028] In this embodiment, the measuring unit 15 includes a high-frequency power supply 151, a resistive element 152, a voltmeter 153, and a memory 154. The high-frequency power supply 151 applies a drive voltage to the piezoelectric element 11 through the signal line 14. The response current 111 of the piezoelectric element 11 is measured by measuring the voltage between both terminals of the resistive element 152 with the voltmeter 153. Data relating to the measured response current 111 is analog-to-digital converted and recorded in the memory 154. The data recorded in the memory 154 is transmitted to the determining unit 16 and used for determination.

[0029] In this embodiment, the vibration state of the piezoelectric element 11 is measured for a reference sample that serves as a reference for judgment and a target sample that is the object of judgment. In this embodiment, the sample 8 is grease used in the drive part of a circuit breaker of a gas-insulated switchgear.

[0030] The reference sample is the same grease as that used in the drive unit, e.g., unused grease that has been confirmed to be undegraded, while the target sample is the same grease as that used in the drive unit, and is placed separately within the detection device 10, in the same environment as the drive unit, and the degree of degradation is determined by the detection device 10.

[0031] In other words, using the expression "system operation," the reference sample is grease that is applied to the measurement reference surface 9 before the gas-insulated switchgear starts system operation, and the target sample is grease that is applied to the measurement reference surface 9 while the gas-insulated switchgear is in system operation. While the gas-insulated switchgear is in system operation, the grease applied to the measurement reference surface 9 deteriorates. Hereinafter, the sample 8 before the gas-insulated switchgear, on which the detection device 10 is to be installed, starts system operation will be referred to as the reference sample, and the sample 8 while the gas-insulated switchgear is in system operation will be referred to as the target sample.

[0032] It should be noted that the vibration state of the piezoelectric element 11 of the reference sample is measured at least once before the determination unit 16 makes a determination.

[0033] The determination unit 16 determines the deterioration of the sample 8 based on the vibration state of the piezoelectric element 11. If the grease in the sample 8 is not deteriorated and has good lubricity, the contact surface between the greased measurement reference surface 9 and the piezoelectric element 11 is free, allowing the piezoelectric element 11 to easily expand and contract. When the piezoelectric element 11 easily expands and contracts in this way, the response current of the piezoelectric element 11 increases. Conversely, if the grease has deteriorated and hardened, causing poor lubricity, the contact surface between the greased measurement reference surface 9 and the piezoelectric element 11 becomes less mobile, making it difficult for the piezoelectric element 11 to expand and contract. When the piezoelectric element 11 has difficulty expanding and contracting in this way, the response current of the piezoelectric element 11 decreases. Therefore, by measuring and monitoring the magnitude of the response current of the piezoelectric element 11, it is possible to estimate the degree of grease deterioration.

[0034] In this embodiment, deterioration of the target sample is determined based on the vibration state of the piezoelectric element 11 measured for the reference sample and the vibration state of the piezoelectric element 11 measured for the target sample. The vibration state of the piezoelectric element 11 is acquired as data on the response current 111 from the memory 154 included in the measurement unit 15.

[0035] The alarm unit 17 outputs an alarm based on the judgment result of the judgment unit. The alarm unit 17 is not an essential component and can be an optional component. When the judgment unit 16 judges that the sample 8 (target sample) has deteriorated, the alarm unit 17 outputs an alarm to the effect that the target sample has deteriorated. In this embodiment, the alarm is an alarm signal to another centralized monitoring device (not shown), and the alarm signal is transmitted to the other centralized monitoring device, for example, via a network 19 by wired communication or wireless communication.

[0036] For example, a known general-purpose computer or various information terminal devices such as a smartphone, which are equipped with a CPU, memory, etc. as hardware, can be used for the determination unit 16 and the warning unit 17. The determination unit 16 and the warning unit 17 can be configured as an integrated unit.

[0037] FIG. 5 is a flowchart showing the processing procedure of the detection method according to the first embodiment.

[0038] In this embodiment, the vibration state of the piezoelectric element 11 is measured for each of a reference sample that serves as a basis for judgment and a target sample that is the subject of judgment. Steps S1 to S2 are steps for preparing for judgment using the reference sample, and steps S3 to S6 are steps for judging the degree of deterioration of the target sample.

[0039] <Preparation> In step S1 (clamping step), the reference sample is sandwiched between the measurement reference surface 9 and the piezoelectric element 11. In this embodiment, unused grease is applied to the surface of the piezoelectric element 11 as the reference sample, and the piezoelectric element 11 and the restrainer 12 are placed so that the grease and the piezoelectric element 11 come into contact with the surface of the drive part of the circuit breaker, which is the measurement reference surface 9.

[0040] In step S2 (measurement step), a drive voltage is applied to the piezoelectric element 11 to measure the vibration state of the piezoelectric element 11 for the reference sample. Data on the response current 111 measured for unused grease, which is the reference sample, is recorded in advance in the memory 154 of the measurement unit 15, for example.

[0041] The preparation for the determination in steps S1 to S2 is performed at least once before the determination of the degree of deterioration in steps S3 to S6, for example, at the time of maintenance before the gas-insulated switchgear is put into system operation.

[0042] <Verdict> In this embodiment, the piezoelectric element 11 and the retainer 12 are removed from the surface of the circuit breaker's drive part, and the reference sample is not removed from the surface of the piezoelectric element 11. Instead, the unused grease used as the reference sample is left on the surface of the circuit breaker's drive part, and the gas-insulated switchgear is then put into system operation. That is, in this embodiment, the reference sample grease used in preparation for the assessment is used as the target sample grease, the target sample for which the degree of degradation is to be assessed. After executing the processes of steps S1 and S2, the processes are repeated from step S3 with the piezoelectric element 11 and the retainer 12 still installed on the surface of the circuit breaker's drive part, to continuously and automatically detect the degradation of the target sample and monitor the degradation status. The assessment of the degree of degradation in steps S3 to S6 is automatically and repeatedly performed while the gas-insulated switchgear is in system operation.

[0043] In step S3 (measurement step), a drive voltage is applied to the piezoelectric element 11 to measure the vibration state of the target sample of the piezoelectric element 11. Data on the response current 111 measured for the target sample is recorded in the memory 154 of the measurement unit 15, for example.

[0044] In step S4 (determination step), deterioration of the target sample is determined based on the vibration state of the piezoelectric element 11 measured for the reference sample and the vibration state of the piezoelectric element 11 measured for the target sample. The determination unit 16 acquires data on the response current 111 of the piezoelectric element 11 measured for the reference sample and data on the response current 111 of the piezoelectric element 11 measured for the target sample from the memory 154 of the measurement unit 15, and determines deterioration of the target sample based on the data on the response current 111.

[0045] If the determination result shows that the target sample has deteriorated (Yes in step S5), an alarm is output in step S6 (alarm step) and the process ends. If the determination result shows that the target sample has not deteriorated (No in step S5), the process is repeated from step S3 after a predetermined measurement interval (for example, one day) has elapsed, and the deterioration of the target sample is continuously and automatically detected and the deterioration status is monitored.

[0046] [Second embodiment] Fig. 6 is a diagram showing a schematic configuration of a detection device according to a second embodiment. Fig. 7 is a diagram showing a state in which two piezoelectric elements according to the second embodiment are arranged facing each other. (A) is a perspective view, and (B) is a side view. For ease of understanding, the restraint device is omitted from Fig. 7.

[0047] In the second embodiment, the detection device 20 determines the deterioration of the sample 8 using two piezoelectric elements 11A and 11B arranged opposite to each other. In the second embodiment, the measurement reference surface 9 is not represented by the surface of the target device on which the detection device 20 is installed, but is represented by the two piezoelectric elements 11A and 11B arranged opposite to each other. That is, in the second embodiment, the first piezoelectric element 11A sandwiches the sample 8 with the surface of the opposing second piezoelectric element 11B serving as the measurement reference surface 9, and the second piezoelectric element 11B sandwiches the sample 8 with the surface of the opposing first piezoelectric element 11A serving as the measurement reference surface 9.

[0048] The configuration of the detection device 20 according to the second embodiment described below is the same as the configuration of the detection device 10 according to the first embodiment unless otherwise specified, and therefore a duplicated description will be omitted.

[0049] The detection device 20 of the second embodiment includes a first piezoelectric element 11A, a second piezoelectric element 11B, a first restraint device 12A, a second restraint device 12B, a measurement unit 15, a judgment unit 16, and an alarm unit 17.

[0050] The detection device 20 according to the second embodiment includes two sets of piezoelectric elements 11 and restraint devices 12 according to the first embodiment. That is, the detection device 20 includes a first set of a first piezoelectric element 11A and a first restraint device 12A and a second set of a second piezoelectric element 11B and a second restraint device 12B. The first restraint device 12A and the second restraint device 12B are combined and attached so that the first piezoelectric element 11A and the second piezoelectric element 11B are arranged opposite each other. The sample 8 is sandwiched between the first piezoelectric element 11A and the second piezoelectric element 11B, which are arranged opposite each other.

[0051] The measuring unit 15 applies a driving voltage to the first piezoelectric element 11A and the second piezoelectric element 11B via the signal lines 14A and 14B, respectively.

[0052] The first piezoelectric element 11A and the second piezoelectric element 11B, which are arranged opposite to each other, are placed on the surface of the driving part of the circuit breaker. The sample 8 is placed in the same environment as the first piezoelectric element 11A and the second piezoelectric element 11B.

[0053] As described above, the sample deterioration detection device according to the embodiment of the present invention can reduce the level of skill required of an operator who installs the device for detecting sample deterioration.

[0054] In the detection devices 10 and 20 according to the embodiments of the present invention, grease as a sample 8, the degree of deterioration of which is to be determined, is arranged so as to be sandwiched between a measurement reference surface 9 and a piezoelectric element 11. The detection devices 10 and 20 are installed by pressing the piezoelectric element 11 against the measurement reference surface 9 on which the sample 8 has been applied. This allows the sample 8 to be easily arranged regardless of the skill of the operator installing the detection devices 10 and 20, and stable determination results can be obtained.

[0055] The detection devices 10 and 20 measure the response current 111 from the piezoelectric element 11 and use it for judgment. As a result, even if gaps or bubbles remain between the grease (sample 8) and the measurement reference surface 9, the response current 111 from the piezoelectric element 11 is measured and used for judgment, so more stable judgment results can be obtained compared to conventional judgment methods using acoustic viscosity sensors that detect surface acoustic waves. Deterioration detection of the sample 8 can also be performed continuously and automatically.

[0056] [Other forms] Although the present invention has been described above with reference to specific embodiments, the present invention is not limited to the above-described embodiments.

[0057] In the above-described embodiment, the piezoelectric elements 11, 11A, and 11B are arranged in a curved state. However, as long as the vibration state of the piezoelectric element 11 can be measured to determine the deterioration of the sample 8, the piezoelectric elements 11, 11A, and 11B do not have to be used in a curved state. Instead of arranging the piezoelectric elements 11, 11A, and 11B in a curved state, the piezoelectric elements 11, 11A, and 11B may be provided on an elastic body having spring properties. Such an elastic body may be formed using, for example, resin or metal, and phosphor bronze, for example, may be used for the elastic body. Any material may be used for the elastic body as long as it has spring properties.

[0058] In the above-described embodiment, the deterioration of the target sample is determined by comparing the measurement results of the reference sample and the target sample, but the method for determining the deterioration of the target sample is not limited to this. For example, the deterioration of the target sample may be determined by comparing with a predetermined threshold value that is set in advance.

[0059] In the above-described embodiment, the deterioration of the target sample is determined by comparing the magnitudes of the response currents 111 of the piezoelectric elements 11, 11A, and 11B, but the measurement values ​​used for the comparison are not limited to this. Instead of the magnitude of the response currents 111, the deterioration of the target sample may be determined by comparing waveform data of the response currents 111. In this case, the waveform data of the response currents 111, which change over time, may be recorded in the memory 154 of the measurement unit 15.

[0060] The method for determining the deterioration of the target sample is not limited to comparing the waveform data of the response current 111 between measurements of a reference sample and measurements of the target sample. For example, the waveform data of the response current 111 obtained by measuring the target sample while the system is in operation may be used as learning data, and the correlation between the actual degree of deterioration of the sample and changes in the measured waveform data may be machine-learned in advance, so that the deterioration of the target sample may be determined only by measurements of the target sample.

[0061] The equipment on which the detectors 10 and 20 are to be installed is not limited to the surface of the drive part of a circuit breaker included in the gas-insulated switchgear described above, but may also be the surface of a drive part of a disconnector or the like, the inner surface of a metal pipe accommodating a busbar for AC power transmission, the surface of a stationary equipment such as a transformer or power converter, the surface of a rotating equipment such as an electric motor, or the surface of power equipment including power transmission and transformation equipment such as a transformer or switchgear. The object on which the detectors 10 and 20 are to be installed may be any surface that is placed in an environment in which the sample 8 deteriorates.

[0062] The sample 8, the degradation of which is to be determined, is not limited to the grease exemplified in the above embodiment. As long as the sample 8 can be sandwiched between the measurement reference surface 9 and the piezoelectric element 11 and the response current 111 of the piezoelectric element 11 can be measured, the degradation of various samples 8, not limited to grease, can be determined.

[0063] The judgment unit 16 and the alarm unit 17 may be configured as an integral part of the measurement unit 15, or may be provided outside the detection devices 10, 20 and connected to the detection devices 10, 20 via a wired or wireless network 19. [Explanation of symbols]

[0064] 8 Samples 9 Measurement reference plane 10. Sample Deterioration Detection Device 11 (11A, 11B) Piezoelectric element (first piezoelectric element, second piezoelectric element) 12 (12A, 12B) Retainer (first retainer, second retainer) 13 Mounting fixture 14(14A,14B) Signal line 15 Measuring part 16 Judgment section 17 Alarm section 19 Network 20 Detection device 111 Response Current 121 Side wall 122 steps 151 High frequency power supply 152 Resistor element 153 Voltmeter 154 memory

Claims

1. a piezoelectric element that sandwiches a sample between itself and a measurement reference surface; a measurement unit that applies a drive voltage to the piezoelectric element and measures the vibration state of the piezoelectric element; a determination unit for determining deterioration of the sample based on the vibration state; A sample deterioration detection device comprising:

2. The detection device according to claim 1 , wherein the piezoelectric element is arranged in a curved state.

3. The detection device according to claim 2 , further comprising a restrainer for holding the piezoelectric element in a curved state.

4. The detection device according to claim 1 , wherein the piezoelectric element is provided on an elastic body.

5. the measuring unit measures the vibration state for each of a reference sample that serves as a reference for judgment and a target sample that is an object of judgment; The detection device according to claim 1 , wherein the determination unit determines deterioration of the target sample based on the vibration state measured for the reference sample and the vibration state measured for the target sample.

6. The detection device according to claim 1 , further comprising an alarm unit that outputs an alarm based on the determination result of the determination unit.

7. the piezoelectric elements include a first piezoelectric element and a second piezoelectric element that are arranged opposite to each other and sandwich the sample therebetween; 7. The detection device according to claim 1, wherein the first piezoelectric element sandwiches the sample with the surface of the opposing second piezoelectric element serving as the measurement reference surface, and the second piezoelectric element sandwiches the sample with the surface of the opposing first piezoelectric element serving as the measurement reference surface.

8. a clamping step of clamping the sample between the measurement reference surface and the piezoelectric element; a measuring step of applying a drive voltage to the piezoelectric element and measuring a vibration state of the piezoelectric element; a determining step of determining deterioration of the sample based on the vibration state; A method for detecting deterioration of a sample, comprising:

9. The measuring step measuring the vibration state of a reference sample that serves as a reference for judgment; measuring the vibration state of a target sample to be determined; Including, 9. The detection method according to claim 8, wherein the determining step determines the deterioration of the target sample based on the vibration state measured for the reference sample and the vibration state measured for the target sample.

10. The detection method according to claim 8 or 9, further comprising an alarm step of outputting an alarm based on the determination result of said determining step.

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