Method for measuring maximum temperature and pressure of temperature and pressure special-shaped sensor

Abstract

The invention provides a maximum temperature and pressure measuring method for a temperature and pressure special-shaped sensor, and relates to the technical field of sensor testing. According to the method, the temperature and pressure special-shaped sensor is installed in an experiment system, and the maximum temperature value and the maximum pressure value are applied to the temperature and pressure special-shaped sensor through temperature and pressure control equipment, so that the sensor is in the maximum temperature and pressure condition; then obtaining a reflection spectrum signal of the sensor through a spectrograph, and demodulating the signal to obtain an optical path difference variable quantity; and finally, the measurement values of the sensor under the maximum temperature value and the maximum pressure value are determined according to the optical path difference variable quantity, systematic verification of the measurement capability of the temperature and pressure special-shaped sensor under the limiting working condition is realized, and a reliable means is provided for evaluating the actual performance of the sensor under the high-temperature and high-pressure environment.

Description

Technical Field

[0001] This invention relates to the field of sensor testing technology, and in particular to a method for measuring the maximum temperature and pressure of a temperature and pressure irregularly shaped sensor. Background Technology

[0002] In the field of high-temperature and high-pressure extreme environment monitoring, the performance verification of temperature and pressure irregularly shaped sensors is crucial, especially their measurement capabilities under their design limits. Currently, there is a lack of a systematic and reliable measurement method to determine whether such sensors can operate stably and accurately at their nominal maximum temperature and pressure values. Conventional testing methods often calibrate only a single physical quantity or are conducted under non-extreme conditions, failing to truly reflect the sensor's comprehensive performance and signal response characteristics when simultaneously subjected to extreme temperatures and pressures. This results in the inability to effectively verify the sensor's maximum measurement capability in practical applications, leading to uncertainty in the reliability and accuracy of its measurements, and consequently limiting the safe application of such sensors in critical fields such as aerospace, energy, and chemical engineering.

[0003] Therefore, there is an urgent need in the field for a solution that can systematically apply the nominal maximum temperature and maximum pressure values ​​to a thermo-pressure shaped sensor and accurately acquire its response signal under these extreme conditions, thereby determining its maximum temperature and pressure measurement value. Summary of the Invention

[0004] To address the aforementioned problems in existing technologies, this invention proposes a method for measuring the maximum temperature and pressure of a non-standard temperature and pressure sensor, comprising: S1: Obtain the thermo-pressure irregular sensor, install the thermo-pressure irregular sensor into the experimental system, and obtain the sensor after installation; S2: Based on the installed sensor, the maximum temperature and maximum pressure values ​​are applied to the installed sensor through the temperature and pressure control equipment of the experimental system to obtain the sensor under the maximum temperature and pressure conditions; S3: Obtain the reflectance spectral signal of the sensor under maximum temperature and pressure conditions using the spectrometer of the experimental system; S4: Demodulate the reflection spectrum signal to obtain the change in optical path difference; S5: Determine the measurement values ​​of the temperature and pressure irregular sensor at the maximum temperature and maximum pressure values ​​based on the change in optical path difference.

[0005] Compared with the prior art, the beneficial effects of the present invention are as follows: Through the close collaboration of five core steps, the challenge of how to systematically verify the measurement capabilities of a thermo- and pressure-sensitive sensor under extreme conditions, as mentioned in the background technology, is effectively solved. First, step S1 involves installing the thermo- and pressure-sensitive sensor into the experimental system, establishing a stable and controllable physical foundation for subsequent application of extreme conditions and accurate measurements, ensuring the reliability of the test environment. Next, step S2, based on this installation foundation, actively applies the sensor's nominal maximum temperature and pressure values ​​to the sensor using the experimental system's temperature and pressure control equipment. This step is crucial, as it proactively creates the most severe operating conditions that the sensor should withstand in its design—the maximum temperature and pressure conditions—ensuring that subsequent measurements accurately reflect the sensor's extreme performance. Then, step S3, under these extreme conditions, acquires the sensor's reflectance spectrum signal using the experimental system's spectrometer. This signal is a direct optical characterization of the sensor's internal physical state changes under extreme temperature and pressure loads, serving as a key information carrier for achieving non-contact, high-precision measurements. Step S4 then demodulates the acquired reflectance spectrum signal to extract the core physical quantity that can quantify the changes in the sensor's internal state—the change in optical path difference. This conversion process is the core step in transforming complex spectral information into physical parameters that can be used for accurate evaluation. Finally, step S5 determines the specific measurement values ​​of the temperature and pressure shaped sensor under the maximum temperature and maximum pressure values ​​based on this change in optical path difference, thereby directly and quantitatively providing the sensor's performance output under extreme conditions.

[0006] The entire process, from building the test environment, actively applying the ultimate load, acquiring key optical signals, demodulating core physical quantities to finally outputting quantitative measurement values, is interconnected, forming a complete and closed-loop measurement chain. This collaboratively achieves an accurate and reliable assessment of the maximum temperature and pressure measurement capability of the temperature and pressure irregular sensor, filling a gap in existing technology. Attached Figure Description

[0007] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0008] Figure 1 The diagram shown is a flowchart illustrating a method for measuring the maximum temperature and pressure of a non-standard temperature and pressure sensor according to an embodiment of the present invention. Detailed Implementation

[0009] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0010] The specific embodiments of the present invention will be described below.

[0011] like Figure 1 As shown, this invention proposes a method for measuring the maximum temperature and pressure of a non-standard temperature and pressure sensor, comprising: S1: Obtain the thermo-pressure irregular sensor, install the thermo-pressure irregular sensor into the experimental system, and obtain the sensor after installation; S2: Based on the installed sensor, the maximum temperature and maximum pressure values ​​are applied to the installed sensor through the temperature and pressure control equipment of the experimental system to obtain the sensor under the maximum temperature and pressure conditions; S3: Obtain the reflectance spectral signal of the sensor under maximum temperature and pressure conditions using the spectrometer of the experimental system; S4: Demodulate the reflection spectrum signal to obtain the change in optical path difference; S5: Determine the measurement values ​​of the temperature and pressure irregular sensor at the maximum temperature and maximum pressure values ​​based on the change in optical path difference.

[0012] This method begins by installing a non-standard thermo-pressure sensor into the experimental system. Here, a "non-standard thermo-pressure sensor" refers to a sensing element with a non-standard structure capable of simultaneously sensing both temperature and pressure. This installation aims to provide a stable and repeatable mechanical and connection foundation for all subsequent tests, ensuring the sensor and experimental system function as a unified whole and avoiding unexpected measurement errors caused by loose connections or misalignment. Next, the experimental system's thermo-pressure control device applies the sensor's nominal maximum temperature and maximum pressure values. These "maximum temperature" and "maximum pressure" values ​​refer to the upper limits of temperature and pressure allowed for normal operation according to the sensor's design specifications. This step is crucial for simulating its extreme operating conditions, aiming to induce sufficient physical deformation or state changes in the sensor's sensitive components under these extreme environments. When the sensor is under these maximum thermo-pressure conditions, its reflectance spectrum signal is acquired using the experimental system's spectrometer. The "reflectance spectrum signal" refers to the light intensity distribution map containing a series of interference peaks or specific spectral patterns formed after light emitted from a broadband light source is reflected internally by the sensor. This signal directly carries information about the changes in the sensor's optical properties caused by temperature and pressure variations.

[0013] Subsequently, the acquired reflectance spectrum signal is demodulated to obtain the change in optical path difference. The change in optical path difference refers to the change in the optical path length of light propagating inside the sensor relative to a certain reference state; it is a key intermediate physical quantity connecting external physical stimuli and internal optical responses. The demodulation process extracts this quantification parameter from the complex reflectance spectrum signal. Finally, based on this change in optical path difference, the measured values ​​of the temperature and pressure shaped sensor at maximum temperature and pressure are determined. Specifically, the "measured values" here refer to the temperature and pressure readings sensed and output by the sensor itself when subjected to maximum ambient temperature and pressure. Its feasibility lies in the fact that, after the sensor is manufactured, there is a definite functional relationship between its change in optical path difference and the external temperature and pressure, which can be obtained through experimental calibration.

[0014] Therefore, once the change in optical path difference under extreme conditions is obtained by demodulating the reflection spectral signal, the sensor can directly map or calculate the temperature and pressure measurements sensed at that moment by querying a pre-stored calibration database containing these correspondences or by substituting the change in optical path difference into a known physical model. This process essentially traces the optical measurement back to the physical quantity, thereby enabling a quantitative evaluation of the sensor's performance under extreme conditions.

[0015] The entire process, from physical installation, environmental simulation, signal acquisition, information extraction to final determination of the quantity, is interconnected and works synergistically to form a complete performance verification method, ensuring the directness and reliability of the evaluation results.

[0016] In some implementations, S1 includes: S1-1: Obtain the thermo-pressure irregular sensor, connect the thermo-pressure irregular sensor to the circulator of the experimental system through optical fiber, and obtain the sensor-circulator connector. S1-2: Based on the sensor-circulator connector, the circulator is connected to the broadband light source and spectrometer of the experimental system to obtain the optical connector; S1-3: Based on the optical connector, the temperature and pressure irregular sensor is placed in the temperature and pressure control device of the experimental system to obtain the sensor after installation.

[0017] In the specific process of installing the sensor, it is first connected to the circulator of the experimental system via optical fiber. An optical fiber is a glass or plastic fiber used to transmit optical signals, and a circulator is a multi-port non-reciprocal optical device that allows the optical signal to be transmitted in a circular sequence from port 1 to port 2, and then from port 2 to port 3. This operation constitutes the sensor-circulator connection, the purpose of which is to establish a dedicated path for the signal to return from the sensor and, utilizing the circulator's unidirectional transmission characteristic, initially physically isolate the incident and reflected light paths. Based on this, the remaining ports of the circulator are connected to a broadband light source and a spectrometer, respectively. A broadband light source is a light source that emits light waves with a certain wavelength range, while a spectrometer is an instrument used to measure the intensity distribution of optical signals at different wavelengths. This step completes the construction of the entire optical connection, enabling the optical signal to be emitted from the broadband light source, guided to the sensor via the circulator, reflected by the sensor, and then directionally guided to the spectrometer by the circulator, forming a complete and controllable test optical path. Finally, the sensing head of the temperature and pressure irregularly shaped sensor, i.e. its sensitive area, is securely placed inside the temperature and pressure control equipment, thus completing the entire installation work.

[0018] This step-by-step connection method ensures the orderliness and stability of the optical path construction. The use of the circulator effectively prevents reflected light from returning to the light source and causing disturbance, ensuring the stability of the incident light signal and laying a solid foundation for obtaining high-quality reflected spectral signals. Finally, placing the sensor in a temperature and pressure control device ensures that the extreme temperature and pressure applied externally can be accurately and effectively transmitted to the sensor's sensitive unit.

[0019] In some implementations, S2 includes: S2-1: Based on the installed sensor, set the temperature parameter of the temperature and pressure control device to the target maximum temperature value and generate a temperature setting signal; S2-2: Based on the temperature setting signal, start the temperature and pressure control device to heat the installed sensor to the target maximum temperature value, and obtain the heated sensor; S2-3: Based on the heated sensor, set the pressure parameter of the temperature and pressure control device to the target maximum pressure value and generate a pressure setting signal; S2-4: Based on the pressure setting signal, start the temperature and pressure control device to apply pressure to the heated sensor to the target maximum pressure value, and obtain the sensor after pressure application; S2-5: Confirm that the sensor is under maximum temperature and pressure conditions after pressure is applied, and obtain the sensor under maximum temperature and pressure conditions.

[0020] A step-by-step strategy was adopted when applying the maximum temperature and pressure conditions. First, based on the installed sensor, the temperature parameter of the temperature and pressure control device was set to the target maximum temperature value, and a drive signal was generated to start the device, heating the sensor until it reached and stabilized at the target temperature, resulting in a heated sensor. This step prioritizes the temperature load, allowing the sensor's material properties, such as the coefficient of thermal expansion, to reach a stable state at high temperatures. Subsequently, based on the sensor in this stable high-temperature state, the pressure parameter of the temperature and pressure control device was set to the target maximum pressure value, and the pressurization function was activated to apply pressure to the sensor until the target value was reached, thus obtaining a sensor that simultaneously withstood both extreme temperature and extreme pressure. This sequential application of temperature before pressure facilitates the observation and analysis of the individual effect of pressure or the coupled effect of both after the temperature effect stabilizes, making the testing process more logical and controllable. Finally, through the device's built-in sensor or stability criteria, it was confirmed that the sensor had been continuously operating within the environment defined by the set maximum temperature and maximum pressure values, i.e., the maximum temperature and pressure conditions.

[0021] This step-by-step verification method ensures the clarity and stability of the test conditions, providing a clearly defined and reliable extreme environment for subsequent acquisition of reflectance spectral signals, and avoiding signal inaccuracies caused by fluctuations in operating conditions.

[0022] In some implementations, S3 includes: S3-1: An incident light signal is generated by emitting a light signal to the sensor under maximum temperature and pressure conditions through a broadband light source; S3-2: The sensor under maximum temperature and pressure conditions reflects the incident light signal to generate a reflected light signal; S3-3: The reflected light signal is transmitted to the spectrometer through the circulator, generating a signal for the guided spectrometer; S3-4: The spectrometer receives and processes the signal from the guided spectrometer to obtain the reflection spectrum signal.

[0023] In the signal acquisition stage, a broadband light source first emits a broadband beam of light towards the sensor, which is operating under maximum temperature and pressure conditions, forming an incident light signal. This light enters the sensor and undergoes multiple reflections and interferences at its internal structural interfaces, such as the end faces forming the Fabry-Perot cavity. These reflected lights, carrying information about cavity length variations, return to the optical fiber, forming a reflected light signal. This reflected light signal travels along the optical fiber to a circulator. The circulator, based on its unidirectional conduction characteristic, guides the signal from the sensor's direction to the port leading to the spectrometer, preventing it from returning to the light source, thus generating a signal directed to the spectrometer. Finally, the spectrometer receives this signal and decomposes it into intensity distributions of different wavelength components, yielding the reflectance spectral signal that can be used for analysis.

[0024] This complete optical path transmission process ensures that changes in the sensor's internal optical properties under extreme environments can be efficiently and faithfully captured and converted into electronic signals. The broadband light source provides rich wavelength components to form clear spectral characteristics, the circulator ensures the unidirectionality of the optical path and the stability of the light source, and the spectrometer realizes the accurate conversion of optical signals to digital signals. The three work together to provide a high-quality data source for subsequent demodulation.

[0025] In some implementations, S4 includes: S4-1: Identify and extract characteristic peak information from the reflectance spectral signal; S4-2: Calculate the wavelength shift corresponding to the characteristic peak information; S4-3: Based on the predefined relationship between wavelength displacement and optical path difference change, convert the wavelength displacement into optical path difference change.

[0026] When demodulating a reflectance spectral signal, the first step is to identify and extract characteristic peak information. "Characteristic peak information" typically refers to the wavelengths of stable and sharp peaks or troughs in the reflectance spectrum, generated by optical interference. These peak wavelengths are extremely sensitive to changes in the sensor's internal cavity length. Next, the wavelength shift corresponding to these characteristic peaks is calculated. The "wavelength shift" is the difference between the characteristic peak wavelength measured under maximum temperature and pressure conditions and the same peak wavelength measured under reference conditions. This shift directly quantifies the spectral drift caused by changes in the sensor's optical cavity length due to temperature and pressure loads. Finally, based on the relationship between wavelength shift and optical path difference change determined beforehand through theoretical models or experimental calibration, the calculated wavelength shift is converted into the final required optical path difference change. This conversion relationship is the physical core of the entire demodulation process; it is based on the principle of optical interference, allowing abstract spectral shifts to be interpreted as concrete changes in physical length.

[0027] By using this demodulation process of extracting features from the spectrum, calculating relative displacement, and then converting based on physical relationships, it is possible to accurately extract the only physical quantity that characterizes the changes in the internal state of the sensor—the change in optical path difference—from the seemingly complex reflectance spectral signal. This provides crucial data input for ultimately determining the sensor's true sensing capability under extreme conditions.

[0028] In some implementations, S5 includes: S5-1: Based on the change in optical path difference, access the stored calibration database. The calibration database contains the correspondence between optical path difference and temperature and the correspondence between optical path difference and pressure, and generates calibration data access results. S5-2: Based on the calibration data access results, map the change in optical path difference to temperature and pressure measurements; S5-3: Use the temperature measurement value and pressure measurement value as the maximum temperature value and maximum pressure value respectively to determine the measurement value of the temperature and pressure irregular sensor at the maximum temperature value and maximum pressure value.

[0029] In determining the sensor's measured value based on the change in optical path difference, a core step involves precise mapping using a pre-established calibration database. This calibration database is not generated ad hoc during measurement but is pre-constructed through a series of precise standard experiments before the sensor leaves the factory or is used. During construction, the sensor is placed in a calibration environment where temperature and pressure are precisely controlled and measurable by higher-precision standard instruments. The temperature is systematically changed while the pressure remains constant, and the change in optical path difference produced by the sensor at different temperatures is recorded, thus establishing a set of data relating optical path difference to temperature. Similarly, the pressure is systematically changed while the temperature remains constant, and the change in optical path difference produced by the sensor at different pressures is recorded, thus establishing another set of data relating optical path difference to pressure. These two sets of data together constitute the calibration database, which essentially stores a unique, quantified mapping between the optical response (change in optical path difference) of a specific sensor and external physical stimuli (temperature, pressure). Once a specific change in optical path difference is obtained by demodulating the reflection spectrum signal during the maximum temperature and pressure measurement, step S5-1 involves accessing the fully stored calibration database based on this measured change in optical path difference. This access operation can be performed automatically by the program to query the data tables in the database. The purpose is to find the corresponding record that best matches the current change in optical path difference. This search and matching process generates the calibration data access result, which clarifies the temperature and pressure values ​​in the database that best match the current change in optical path difference.

[0030] Next, step S5-2 performs a crucial mapping transformation based on the calibration data access results. Since the calibration database clearly defines the correspondence between the change in optical path difference and the temperature value, as well as the correspondence between the change in optical path difference and the pressure value, the system can accurately decompose and map the single, comprehensive optical physical quantity of the change in optical path difference into two physical quantities with clear engineering significance—the temperature measurement value and the pressure measurement value—based on these preset, one-to-one correspondences. It is important to understand that inside the sensor, the combined effect of temperature and pressure ultimately manifests as a total change in optical path difference, and the calibration database and its mapping process are the mathematical and physical tools for the reverse decoupling of this comprehensive effect. Finally, step S5-3 identifies the two mapped values—the temperature measurement value and the pressure measurement value—as the specific measurement results of the temperature-pressure irregular sensor under the extreme conditions of this test, specifically for the maximum temperature and maximum pressure values. The term "measured value" here has a dual meaning: it refers both to the temperature and pressure readings sensed by the sensor itself when subjected to the maximum external temperature and pressure values; and to the two output quantities ultimately determined by this method for evaluating sensor performance. The logic of directly using the mapped value as the final measured value lies in the traceability of the entire measurement chain: from applying known limiting standard conditions, to obtaining the optical response, and then to reverse calculation through a standard database, the final output measured value should directly correspond to the applied limiting conditions.

[0031] The effectiveness of this method lies in transforming a complex physical measurement problem into a reliable data query and mapping process based on prior calibration, significantly improving the accuracy and repeatability of the final result determination. By accessing a calibration database containing independent correspondences between optical path difference and temperature and pressure, the intermediate variable of optical path difference variation is given a clear physical meaning, allowing it to be accurately interpreted as a specific environmental parameter. Mapping based on calibration data access results ensures the objectivity and consistency of the conversion process from optical signal to physical quantity, avoiding subjective errors that may arise from human interpretation. The mapped temperature and pressure measurements are directly used as the response output to the maximum temperature and pressure conditions, making the measurement results directly correspond to the sensor's performance under extreme conditions. The entire S5 step relies on rigorous prior calibration work, simplifying the complex data processing at the measurement site into efficient database access and mapping, ensuring not only accuracy but also improving measurement efficiency, ultimately providing a solid and reliable data endpoint for evaluating the sensor's maximum temperature and pressure measurement capabilities. This database-based determination method's reliability is rooted in the quality of prior calibration, allowing on-site measurement results to be directly traceable to standard values, forming the cornerstone of the entire measurement method's credibility.

[0032] In some implementations, the thermo-pressure sensor in S1 is a sapphire coaxial thermo-pressure sensor with different diameters. The sapphire coaxial thermo-pressure sensor includes a temperature-sensitive microcavity, a hollow pressure-sensitive microcavity, and an elastic pressure-sensitive diaphragm. S1 includes: A sapphire coaxial temperature and pressure sensor with different diameters was obtained. The structural parameters of the temperature-sensitive microcavity, the hollow pressure-sensitive microcavity, and the elastic pressure-sensitive diaphragm were confirmed. The sapphire coaxial temperature and pressure sensor with confirmed structural parameters was then fixed to the ceramic ferrule with adhesive to obtain the glued sensor. Based on the glued sensor, the ceramic ferrule is connected to the optical fiber to obtain the installed sensor.

[0033] In this embodiment, the thermo-pressure sensor is specifically a sapphire coaxial thermo-pressure sensor with different diameters. This sensor is a special type of sensor made of sapphire material, featuring a coaxial but differently shaped microcavity structure. Its core components include a temperature-sensitive microcavity, a hollow pressure-sensitive microcavity, and an elastic pressure-sensitive diaphragm. The temperature-sensitive microcavity is a Fabry-Perot interferometer that is sensitive to temperature changes; its length expands or contracts with temperature variations. The hollow pressure-sensitive microcavity is another Fabry-Perot interferometer that is sensitive to pressure changes. The elastic pressure-sensitive diaphragm is a thin-film structure that undergoes elastic deformation under pressure, and this deformation directly alters the length of the pressure-sensitive microcavity. During installation, it is first necessary to obtain the sapphire coaxial thermo-pressure sensor with a defined structure and confirm the key structural parameters of its temperature-sensitive microcavity, hollow pressure-sensitive microcavity, and elastic pressure-sensitive diaphragm, such as the initial length of the cavity, the thickness and diameter of the diaphragm, etc. These parameters form the physical basis for subsequent demodulation and calculation. Subsequently, the sensor, whose structural parameters have been confirmed, is securely fixed to a ceramic ferrule using a high-temperature resistant adhesive. The ceramic ferrule is a precision ceramic component, typically containing micropores for aligning and securing the optical fiber. This adhesive bonding step creates the bonded sensor, aiming to mechanically fix the sensitive sapphire sensor to a robust and stable support, while ensuring precise and fixed relative positioning between the sensor and the subsequently connected optical fiber. This prevents micro-movements or slippage under pressure or temperature, thus avoiding measurement errors. Based on the bonded sensor, the ceramic ferrule is then precisely mated and fixedly connected to the optical fiber transmitting the optical signal, ultimately resulting in a mechanically robust sensor with precise optical path alignment.

[0034] This specific sensor structure and installation method ensures that, when subjected to extreme temperature and pressure conditions, the two sensitive microcavities inside the sensor can independently and accurately respond to changes in temperature and pressure, converting these physical changes into independent optical signal changes. This lays a solid physical foundation for subsequent demodulation of temperature and pressure. The use of sapphire material benefits from its excellent high-temperature stability and mechanical strength, enabling it to withstand extreme environments. The coaxial, unequal-diameter design achieves a close spatial correlation and relative physical independence between the temperature and pressure signals, facilitating optical differentiation. Fixing it to the ceramic ferrule with adhesive solves the technological challenge of reliably connecting the brittle sapphire material to the optical fiber, ensuring the structural integrity and signal transmission continuity of the entire sensor head under harsh conditions.

[0035] In some implementations, S2 includes: Obtain the design maximum temperature and design maximum pressure values ​​from the design documents of the installed sensor; Set the temperature parameter of the temperature and pressure control equipment to the maximum design temperature value, and the pressure parameter of the temperature and pressure control equipment to the maximum design pressure value; By applying the designed maximum temperature and maximum pressure values ​​to the installed sensor using a temperature and pressure control device, the sensor is obtained under maximum temperature and pressure conditions.

[0036] In another implementation of applying maximum temperature and pressure conditions, the maximum temperature and pressure values ​​are determined directly from the sensor's design specifications. Specifically, the design maximum temperature and design maximum pressure values ​​are obtained from the sensor's design documentation after installation. The design documentation is a technical document defining the sensor's performance specifications, explicitly specifying the upper temperature and pressure limits at which the sensor is designed to operate normally. This step directly links the test conditions to the product's design standards, ensuring the relevance and authority of the performance verification. Next, the temperature parameter of the temperature and pressure control device is set to the previously obtained design maximum temperature value, and its pressure parameter is set to the design maximum pressure value. This means that the target control point of the temperature and pressure control device is directly set to the theoretically maximum operating conditions that the sensor can withstand. Subsequently, these two design maximum values—the design maximum temperature and design maximum pressure—are applied synchronously or sequentially to the installed sensor through the temperature and pressure control device, thereby bringing the sensor into the most severe operating state allowed by its design, i.e., obtaining the sensor under maximum temperature and pressure conditions.

[0037] This method eliminates the step of manually setting or selecting test conditions, making the testing process entirely based on the product's objective design specifications, thus ensuring standardization and comparability. It directly verifies whether the sensor meets its design specifications, which is crucial for product conformity inspection and quality control. In this way, the core question of "whether the sensor can operate normally under its nominal design limits" can be answered most directly, providing indisputable experimental evidence for judging whether the product has achieved its design goals.

[0038] In some implementations, S4 includes: S4-1: Perform a Fourier transform on the reflection spectrum signal to generate a frequency domain signal; S4-2: Extracting phase feature information from frequency domain signals; S4-3: Based on the preset ratio between the wavenumber and phase of the light wave, calculate the change in optical path difference corresponding to the phase characteristic information.

[0039] In another implementation of demodulating the reflection spectrum signal to obtain the optical path difference change, a signal processing technique based on frequency domain analysis is employed. First, a Fourier transform is performed on the acquired reflection spectrum signal. The Fourier transform is a mathematical tool that converts a signal from the wavelength domain to the frequency domain. After this transform, the periodic interference information contained in the reflection spectrum signal manifests as specific peaks in the frequency domain signal. The frequencies corresponding to these peaks are directly related to the cavity length of the optical cavity in the sensor. This transformation effectively separates noise mixed in with the original spectrum from the true interference signal, because noise is usually widely distributed in the frequency domain, while the true interference signal is concentrated near specific frequency points, thereby improving the signal-to-noise ratio of the signal processing. Next, phase feature information corresponding to the cavity length is extracted from the transformed frequency domain signal. The phase feature information reflects the phase change of the light wave during one round trip within the sensor cavity, and it is extremely sensitive to minute changes in the cavity length. Finally, based on the optical principle that there is a fixed proportional relationship between the wave number and the phase of a light wave, the wave number is defined as 2π divided by the wavelength. The amount of phase change is proportional to the amount of optical path difference change, so the corresponding amount of optical path difference change can be calculated from the extracted phase feature information.

[0040] This demodulation method based on Fourier transform and phase analysis is particularly suitable for processing reflectance spectral signals with low signal-to-noise ratio or low contrast of interference fringes. It effectively suppresses noise interference through frequency domain analysis and utilizes the high sensitivity of phase information to cavity length changes to achieve optical path difference measurement with higher accuracy than simply tracking peak wavelength. It is especially suitable for detecting minute deformations that may occur under extreme temperature and pressure conditions.

[0041] In some implementations, S5 includes: S5-1: Based on the change in optical path difference, obtain the reference optical path difference change corresponding to the maximum temperature value and the maximum pressure value from the reference database; S5-2: Calculate the difference between the change in optical path difference and the change in the reference optical path difference; S5-3: If the difference is within the preset acceptable range, the measurement value of the temperature and pressure shaped sensor at the maximum temperature and maximum pressure values ​​shall be determined based on the change in optical path difference.

[0042] In another implementation of determining the final measured value based on the change in optical path difference, a comparison step is introduced to verify the accuracy of the measurement. First, based on the change in optical path difference calculated from the current reflectance spectral signal, a corresponding reference change in optical path difference is retrieved from a pre-established reference database. This database stores standard optical path difference change data calibrated using standard measuring instruments under known, precisely controlled maximum temperature and pressure conditions. Next, the difference between the currently measured change in optical path difference and the reference change in optical path difference retrieved from the database is calculated. This difference quantifies the deviation between the current measured response of the sensor and the ideal standard response. Then, this difference is compared with a preset acceptable range. This acceptable range is a threshold set based on the allowable measurement error range of the sensor. If the calculated difference is within this preset acceptable range, it indicates that the sensor's response matches expectations, and its performance is within the allowable error range. Only then, based on the change in optical path difference, is the final measured value of the temperature and pressure shaped sensor at the maximum temperature and maximum pressure values ​​determined through a predetermined mapping relationship or calculation model.

[0043] This process adds a verification mechanism that not only obtains the measured values ​​but also assesses their reliability. By comparing the measured data with reference standards, it effectively identifies measurements that, while yielding results, may be unreliable due to sensor performance degradation, installation issues, or accidental interference. This ensures the correctness and validity of the final results, which is crucial for rigorous performance verification and product screening.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the technical solutions of the embodiments of the present invention.

Claims

1. A method for measuring the maximum temperature and pressure of a non-standard temperature and pressure sensor, characterized in that, include: S1: Obtain the thermo-pressure irregular sensor, install the thermo-pressure irregular sensor into the experimental system, and obtain the sensor after installation; S2: Based on the installed sensor, the maximum temperature and maximum pressure values ​​are applied to the installed sensor through the temperature and pressure control equipment of the experimental system to obtain the sensor under the maximum temperature and pressure conditions; S3: Obtain the reflectance spectral signal of the sensor under maximum temperature and pressure conditions using the spectrometer of the experimental system; S4: Demodulate the reflection spectrum signal to obtain the change in optical path difference; S5: Determine the measurement values ​​of the temperature and pressure irregular sensor at the maximum temperature and maximum pressure values ​​based on the change in optical path difference.

2. The method for measuring the maximum temperature and pressure of a non-standard temperature and pressure sensor according to claim 1, characterized in that, S1 includes: S1-1: Obtain the thermo-pressure irregular sensor, connect the thermo-pressure irregular sensor to the circulator of the experimental system through optical fiber, and obtain the sensor-circulator connector. S1-2: Based on the sensor-circulator connector, the circulator is connected to the broadband light source and spectrometer of the experimental system to obtain the optical connector; S1-3: Based on the optical connector, the temperature and pressure irregular sensor is placed in the temperature and pressure control device of the experimental system to obtain the sensor after installation.

3. The method for measuring the maximum temperature and pressure of a non-standard temperature and pressure sensor according to claim 1, characterized in that, S2 include: S2-1: Based on the installed sensor, set the temperature parameter of the temperature and pressure control device to the target maximum temperature value and generate a temperature setting signal; S2-2: Based on the temperature setting signal, start the temperature and pressure control device to heat the installed sensor to the target maximum temperature value, and obtain the heated sensor; S2-3: Based on the heated sensor, set the pressure parameter of the temperature and pressure control device to the target maximum pressure value and generate a pressure setting signal; S2-4: Based on the pressure setting signal, start the temperature and pressure control device to apply pressure to the heated sensor to the target maximum pressure value, and obtain the sensor after pressure application; S2-5: Confirm that the sensor is under maximum temperature and pressure conditions after pressure is applied, and obtain the sensor under maximum temperature and pressure conditions.

4. The method for measuring the maximum temperature and pressure of a non-standard temperature and pressure sensor according to claim 1, characterized in that, S3 include: S3-1: An incident light signal is generated by emitting a light signal to the sensor under maximum temperature and pressure conditions through a broadband light source; S3-2: The sensor under maximum temperature and pressure conditions reflects the incident light signal to generate a reflected light signal; S3-3: The reflected light signal is transmitted to the spectrometer through the circulator, generating a signal for the guided spectrometer; S3-4: The spectrometer receives and processes the signal from the guided spectrometer to obtain the reflection spectrum signal.

5. The method for measuring the maximum temperature and pressure of a non-standard temperature and pressure sensor according to claim 1, characterized in that, S4 include: S4-1: Identify and extract characteristic peak information from the reflectance spectral signal; S4-2: Calculate the wavelength shift corresponding to the characteristic peak information; S4-3: Based on the predefined relationship between wavelength displacement and optical path difference change, convert the wavelength displacement into optical path difference change.

6. The method for measuring the maximum temperature and pressure of a non-standard temperature and pressure sensor according to claim 1, characterized in that, S5 include: S5-1: Based on the change in optical path difference, access the stored calibration database. The calibration database contains the correspondence between optical path difference and temperature and the correspondence between optical path difference and pressure, and generates calibration data access results. S5-2: Based on the calibration data access results, map the change in optical path difference to temperature and pressure measurements; S5-3: Use the temperature measurement value and pressure measurement value as the maximum temperature value and maximum pressure value respectively to determine the measurement value of the temperature and pressure irregular sensor at the maximum temperature value and maximum pressure value.

7. The method for measuring the maximum temperature and pressure of a non-standard temperature and pressure sensor according to claim 1, characterized in that, The S1 temperature and pressure sensor is a sapphire coaxial temperature and pressure sensor with varying diameters. The sapphire coaxial temperature and pressure sensor includes a temperature-sensitive microcavity, a hollow pressure-sensitive microcavity, and an elastic pressure-sensitive diaphragm. S1 includes: A sapphire coaxial temperature and pressure sensor with different diameters was obtained. The structural parameters of the temperature-sensitive microcavity, the hollow pressure-sensitive microcavity, and the elastic pressure-sensitive diaphragm were confirmed. The sapphire coaxial temperature and pressure sensor with confirmed structural parameters was then fixed to the ceramic ferrule with adhesive to obtain the glued sensor. Based on the glued sensor, the ceramic ferrule is connected to the optical fiber to obtain the installed sensor.

8. The method for measuring the maximum temperature and pressure of a non-standard temperature and pressure sensor according to claim 1, characterized in that, S2 includes: Obtain the design maximum temperature and design maximum pressure values ​​from the design documents of the installed sensor; Set the temperature parameter of the temperature and pressure control equipment to the maximum design temperature value, and the pressure parameter of the temperature and pressure control equipment to the maximum design pressure value; By applying the designed maximum temperature and maximum pressure values ​​to the installed sensor using a temperature and pressure control device, the sensor is obtained under maximum temperature and pressure conditions.

9. The method for measuring the maximum temperature and pressure of a non-standard temperature and pressure sensor according to claim 1, characterized in that, S4 includes: S4-1: Perform a Fourier transform on the reflection spectrum signal to generate a frequency domain signal; S4-2: Extracting phase feature information from frequency domain signals; S4-3: Based on the preset ratio between the wavenumber and phase of the light wave, calculate the change in optical path difference corresponding to the phase characteristic information.

10. The method for measuring the maximum temperature and pressure of a non-standard temperature and pressure sensor according to claim 1, characterized in that, S5 include: S5-1: Based on the change in optical path difference, obtain the reference optical path difference change corresponding to the maximum temperature value and the maximum pressure value from the reference database; S5-2: Calculate the difference between the change in optical path difference and the change in the reference optical path difference; S5-3: If the difference is within the preset acceptable range, the measurement value of the temperature and pressure shaped sensor at the maximum temperature and maximum pressure values ​​shall be determined based on the change in optical path difference.

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