A multifunctional measuring system based on fluorescence thermometry

Abstract

This invention belongs to the field of temperature monitoring technology, specifically relating to a multifunctional measurement system based on fluorescence thermometry. It includes a well furnace, a fluorescent powder pellet, a signal amplifier, a detector, a host computer, and a replaceable integrated device cover. The replaceable integrated device cover has two modes: Mode 1, using six LEDs as the light source for the fluorescence intensity ratio method, and Mode 2, using a pulsed laser as the light source for the fluorescence lifetime method. Compared with existing equipment, this invention can not only simulate vacuum or various gas environments, but also perform both intensity ratio and lifetime temperature measurement methods with a single device, truly achieving multi-purpose functionality. This invention features a high degree of integration, optimized optical path structure, high upper limit of temperature measurement, non-contact temperature measurement, wide range of applications, and significant practical value.

Description

Technical Field

[0001] This invention belongs to the field of temperature monitoring technology, specifically relating to a multifunctional measurement system based on fluorescence thermometry. Background Technology

[0002] Temperature monitoring is considered essential in daily life and industrial production. Traditional thermometers and measurement methods, such as thermocouples, infrared pyrometers, thermistors, and temperature-indicating paint, are relatively mature in various applications. However, in some special environments, such as internal combustion engines, gas turbines, and aero engines, the characteristics of ultra-high temperature, ultra-high pressure, complex structure, high-speed movement, and severe vibration limit the application of traditional thermal parameter monitoring technologies. Temperature measurement technology based on fluorescence optical properties offers advantages such as high precision, non-contact, non-destructive detection, and transient response, making it well-suited for measuring thermal parameters in complex and harsh environments. It has already been successfully applied to the internal temperature measurement of power units such as automotive engines and gas turbines.

[0003] The fundamental reason for optical temperature sensing is that when the temperature changes, the optical parameters change synchronously. Generally speaking, the optical parameters affected by temperature mainly include: (a) fluorescence intensity ratio, (b) fluorescence lifetime, (c) fluorescence intensity, (d) peak position of fluorescence emission characteristic peak, (e) polarization, and (f) spectral linewidth. Among them, the intensity ratio method and lifetime method are often used for temperature measurement, while the other methods are difficult to use for practical temperature detection due to many limitations.

[0004] Temperature measurement using the ratio of fluorescence intensities offers advantages over traditional intensity methods, adapting to more complex testing environments. The ratio method's strengths include information dependent on changes in the intensity ratio, unaffected by variations in light source power, wavelength fluctuations, fiber optic bending, and light intensity loss, and less susceptibility to stress. This results in significantly improved sensitivity and accuracy, and the algorithm is relatively simple to implement. Temperature measurement using the fluorescence lifetime of fluorescent materials offers typical advantages of optical measurement techniques, such as resistance to electromagnetic interference, good repeatability, and fast response. Furthermore, lifetime is an intrinsic parameter, unaffected by factors such as the uniformity of excitation light source illumination, phosphor concentration, surface curvature, thickness, and fluctuations in excitation light intensity.

[0005] The fluorescence intensity ratio method uses a continuous excitation light source, which has relatively low requirements for the light source but a long response time. The fluorescence lifetime method uses a pulsed excitation light source, which has higher requirements for the light source, often using high-power LEDs or pulsed lasers, and a short response time. It is difficult to achieve a single device suitable for multiple purposes in the selection of testing equipment for these two methods. Surveys have found that while there are many devices that can perform measurements using a single method, devices that can perform both methods are rare. Summary of the Invention

[0006] (a) Technical problems to be solved

[0007] The technical problem to be solved by this invention is: how to improve the shortcomings of traditional fluorescence thermometry equipment, such as complexity, low integration, and single equipment only being applicable to one temperature measurement method. The invention provides a method that uses a well furnace as the calibration experimental environment and uses a replaceable integrated device to cover the same equipment to achieve temperature measurement by intensity ratio method and lifetime method. The whole set of equipment has a simple structure, low manufacturing cost, selectable temperature measurement environment, good temperature stability, and high temperature measurement accuracy.

[0008] (II) Technical Solution

[0009] To solve the above technical problems, the present invention provides a multifunctional measurement system based on fluorescence thermometry. The multifunctional measurement system includes: a well furnace (1) with a built-in temperature control system, a stage (3) located inside the well furnace (1), a replaceable device cover (7) that can collect fluorescence measurement information, and an information processing module that receives the fluorescence signal transmitted by the replaceable device cover (7).

[0010] The well furnace (1) is used to simulate a real temperature measurement environment. It has a cylindrical well furnace cavity (2) inside, and a quartz window (9) is installed in the center of its upper part.

[0011] The stage (3) is located at the upper center of the inner cavity (2) of the pit furnace, and a fluorescent powder press (4) is fixed on the upper surface of the stage (3);

[0012] The replaceable device cover (7) is fitted around the quartz window (9) to excite the fluorescent material of the fluorescent powder tablet (4) to generate a fluorescent signal and to collect the fluorescent signal through an optical fiber.

[0013] The information processing module includes a function to receive fluorescence signals transmitted back from the optical fiber, analyze and process the signal data, and obtain temperature measurement information.

[0014] The well furnace (1) is provided with an air inlet (5), a water inlet (6), a flange (8), a quartz window (9), a water outlet (10), and an air extraction port (11);

[0015] The top of the pit furnace (1) has a round hole for mounting the flange (8); the center of the flange (8) has a hole for mounting the quartz window (9); the gas inlet (5) and the gas outlet (11) are located on both sides of the top of the pit furnace (1) to keep the furnace in a vacuum or protective gas environment; the water inlet (6) and the water outlet (10) are the two ends of the water cooling device to effectively reduce the damage of the high temperature environment inside the furnace to other supporting equipment inside the pit furnace (1).

[0016] The information processing module includes a signal amplifier (12), a detector (13), and a host computer (14) connected in sequence. The signal amplifier (12) receives the fluorescence signal transmitted from the optical fiber and amplifies the signal. The signal amplifier (12) is connected to the detector (13), and the detector (13) is connected to the host computer (14) to analyze and process the signal data and obtain temperature measurement information.

[0017] The detector (13) is selected differently according to different testing requirements. For point temperature testing, avalanche photodiodes and photomultiplier tubes are selected; for surface temperature measurement, area array CCD cameras and multi-channel high-speed cameras are selected.

[0018] The stage (3), which has good thermal conductivity and is placed in a high-temperature environment, is used to adjust the position of the fluorescent powder press (4) to ensure that the fluorescent powder press (4) is heated more evenly and the referenced temperature control value is more reliable.

[0019] The replaceable device cover (7) is configured in different forms according to different fluorescence thermometry methods, including fluorescence intensity ratio thermometry and fluorescence lifetime thermometry.

[0020] Among them, the replaceable device cover (7) for the fluorescence intensity ratio thermometry method is an inverted stainless steel container, and the outer shell is the first outer shell (15).

[0021] The first outer shell (15) has several evenly distributed circular holes around its top; a pressure ring (18) is provided at each circular hole, and the pressure ring (18) is used to connect the lens sleeve (16);

[0022] A quartz lens (17) is fixed inside the lens sleeve (16) by a retaining ring. The quartz lens (17) can be focused by adjusting the position of the lens sleeve (16).

[0023] Above each quartz lens (17), there is an LED light (19). Several LED lights (19) are controlled by a synchronous trigger (20). The LED lights (19) are installed in a suitable position above the quartz lens (17) to ensure that the excitation light of more LED lights (19) shines on the fluorescent powder press (4) through the quartz lens (17).

[0024] A first square hole is opened at the top center of the first housing (15) to install a first short-pass filter (26). The first short-pass filter (26) allows light below 600nm to pass through in order to reduce the influence of blackbody radiation.

[0025] On the inner side of the first square hole below, a first single-board machine lens mount (27) is fixed, and a first single-board machine lens (28) is connected to the first single-board machine lens mount (27) for collecting the fluorescence emitted by the fluorescent material;

[0026] On the outer side of the first square hole, a first FC fiber mounting base (25) is fixed. The first FC fiber mounting base (25) is connected to a second Y-type fiber (24). The light inlet port of one end of the second Y-type fiber (24) is set at the focal point of the first single-board camera lens (28) to ensure that more fluorescence is detected.

[0027] The other end of the second Y-type optical fiber (24) is connected to one end of the first Y-type optical fiber (21), and a first narrowband filter (22) and a second narrowband filter (23) are coupled at the connection between the second Y-type optical fiber (24) and the first Y-type optical fiber (21);

[0028] The other end of the first Y-shaped optical fiber (21) is connected to a signal amplifier (12).

[0029] The overall calibration process of the fluorescence intensity ratio thermometry method is as follows: several LEDs (19) are controlled by a synchronous trigger (20) to excite the fluorescent material of the fluorescent powder tablet (4). When the temperature is known, the fluorescence signals of the two target peak wavelengths are collected by the quartz optical fibers of the first Y-type optical fiber (21) and the second Y-type optical fiber (24). The ratio of fluorescence intensity is recorded by the information processing module consisting of the signal amplifier (12), the detector (13) and the host computer (14). By repeating the operation multiple times, a temperature-fluorescence intensity ratio relationship curve can be determined.

[0030] Based on the calibrated relationship curve, temperature measurement information can be obtained by calculating the fluorescence intensity ratio.

[0031] Among them, the replaceable device cover (7) for the fluorescence lifetime thermometry method is an inverted stainless steel container, and the outer shell is a second outer shell (29).

[0032] A second square hole is opened at the center of the top of the second housing (29). A second short-pass filter (32) and a third narrow-band filter (33) are installed in the second square hole. The second short-pass filter (32) allows light below 600nm to pass through, effectively reducing the influence of blackbody radiation. The third narrow-band filter (33) allows light of the target peak wavelength to pass through.

[0033] A second single-board camera lens mount (31) is fixed on the inner side of the second square hole below. The second single-board camera lens mount (31) is connected to the second single-board camera lens (30) and is used to collect the fluorescence emitted by the fluorescent material.

[0034] On the outer side of the second square hole above, a second FC fiber optic mounting base (34) is fixed. The second FC fiber optic mounting base (34) is connected to a quartz fiber (35). The light inlet of one end of the quartz fiber (35) is located at the focal point of the second single-board camera lens (30) to ensure that more fluorescence is detected. The other end of the quartz fiber (35) is connected to a signal amplifier (12).

[0035] An outwardly extending light shield (36) is provided on the side of the second housing (29); the light outlet of the laser (37) is inserted into the light shield (36); a reflector mounting base (39) is provided on the inner wall of the second housing (29), the reflector mounting base (39) is located in the inner cavity of the second housing (29), and a reflector (38) is provided on it. The light emitted by the laser (37) is irradiated onto the fluorescent powder press (4) at a certain angle through the reflector (38); the reflector mounting base (39) is used to fix and adjust the angle of the reflector (38).

[0036] The overall calibration process of the fluorescence lifetime thermometry method is as follows: a laser (37) source emits a pulse excitation light to irradiate the fluorescent material of the fluorescent powder pellet (4). The fluorescent material is excited and generates a fluorescence signal. When the excitation disappears, the fluorescence intensity decays rapidly. When the temperature is known, the fluorescence decay lifetime can be obtained through the information processing module composed of signal amplifier (12), detector (13) and host computer (14). By repeating the operation multiple times, a temperature-fluorescence lifetime relationship curve can be determined.

[0037] Temperature measurement information can be obtained by calculating the fluorescence lifetime based on the calibrated relationship curve.

[0038] (III) Beneficial Effects

[0039] Compared with existing technologies, this invention achieves multiple uses with a replaceable integrated device cover, and uses a pit furnace as the test environment for calibration experiments, making it easier to install supporting devices. This is of great significance to teams researching fluorescence thermometry.

[0040] Specifically, the system provided by this invention can perform multiple functions, and both the fluorescence intensity ratio method and the lifetime method can obtain good temperature measurement data through this system.

[0041] The beneficial effects of this invention are as follows: temperature measurement using both the intensity ratio method and the lifespan method is realized through two modes of replaceable device covers; the atmosphere protection system can more realistically reproduce the gas environment of the measured temperature field, making the calibration data more applicable to complex temperature measurement environments; it achieves integration and miniaturization, and the equipment operation process is simple, providing a very convenient experimental device for relevant temperature measurement teams, and has great hope and potential to be applied to real life as soon as possible. Attached Figure Description

[0042] Figure 1 This is an overall structural diagram of the temperature measurement system of the present invention.

[0043] Figure 2 This is an overall structural diagram of a replaceable device cover that uses multiple LED lights as excitation light sources.

[0044] Figure 3 This is an overall structural diagram of a replaceable device cover that uses a laser as the excitation light source. Detailed Implementation

[0045] To make the objectives, contents, and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0046] Example 1

[0047] The overall structural diagram of this embodiment is as follows: Figure 1 As shown, first refer to Figure 1 Detailed instructions on setting up a temperature measurement system.

[0048] For ease of explanation, the system is divided into the following four parts: The first part includes a pit furnace (1), a pit furnace cavity (2), an air inlet (5), a water inlet (6), a flange (8), a quartz window (9), a water outlet (10), and an air extraction port (11); the second part includes a stage (3) and a fluorescent powder press (4); the third part includes a signal amplifier (12), a detector (13), and a host computer (14); and the fourth part includes a replaceable device cover (7).

[0049] The first part is a pit furnace (1) that simulates a real temperature measurement environment and has its own temperature control system; the inner cavity (2) of the pit furnace is a cylinder with a bottom diameter of 240mm and a height of 250mm; a circular hole with a diameter of 120mm is opened on the top of the pit furnace (1) to install a flange (8) with a diameter of 140mm and a height of 86mm; a hole with a diameter of 80mm is opened in the center of the flange (8) to install a quartz window (9) with a diameter of 80mm; the air inlet (5) and the air outlet (11) are located on both sides of the top of the pit furnace (1) to keep the furnace in a vacuum or special protective gas environment; the water inlet (6) and the water outlet (10) are the two ends of the water cooling device to effectively reduce the damage of the high temperature environment inside the furnace to other supporting equipment.

[0050] The second part is a stage (3) with good thermal conductivity placed in a high-temperature environment, used to adjust the position of the fluorescent powder pellet (4) so ​​that it is located in the center of the well furnace cavity (2). This ensures that the fluorescent powder pellet (4) is heated more evenly and the reference temperature control value is more reliable. The fluorescent powder pellet (4) is fixed to the surface of the stage (3) by a slot.

[0051] The third part is a standard structure for receiving and processing information. The fluorescence signal transmitted by the optical fiber is a weak signal and needs to be amplified by the signal amplifier (12). The signal amplifier (12) is a Variable Gain Photoreceiver-Fast Optical Power Meter of model 0E-200-SI manufactured by FEMTOMesstechnik GmbH, Germany. The detector (13) is selected according to different test requirements. For point temperature testing, avalanche photodiode (APD) and photomultiplier tube (PMT) can be selected. For surface temperature measurement, area array CCD camera and multi-channel high-speed camera can be selected. The detector (13) is connected to the host computer (14) for data analysis and processing.

[0052] The fourth part is a replaceable device cover (7), which has two modes, see attached document. Figure 2 and attached Figure 3 The following section provides further explanation of this part, in conjunction with relevant accompanying drawings and specific examples.

[0053] To achieve temperature measurement of the surface of rotating blades of aero-engines, YAG:Dy is preferred as the phosphor used in the test. This phosphor is suitable for both intensity ratio method and lifetime method, and its absorption wavelength can be selected as 355nm or 365nm; the excitation peak wavelengths are 458nm and 497nm. As the temperature increases, the peak fluorescence intensity at 458nm increases, and the peak fluorescence intensity at 497nm decreases.

[0054] The replaceable device cover (7) is configured in different forms according to different fluorescence thermometry methods. The different fluorescence thermometry methods include: fluorescence intensity ratio thermometry and fluorescence lifetime thermometry.

[0055] Replaceable cover for fluorescence intensity ratio thermometry (7) Figure 2 As shown, the replaceable device cover (7) is an inverted stainless steel container with a bottom thickness of 3mm, a bottom diameter of 18.5mm, a height of 18mm, and an outer shell shape of the first outer shell (15).

[0056] The first outer shell (15) has 6 evenly distributed circular holes around its top, only two of which are shown in the figure; a pressure ring (18) is provided at each circular hole and fixed by screws. The pressure ring (18) is used to connect the lens sleeve (16), and the inner diameter of the lens sleeve (16) is 12.7 mm.

[0057] A quartz lens (17) is fixed at a suitable position inside the lens sleeve (16) by a retaining ring. The quartz lens (17) can be focused by adjusting the position of the lens sleeve (16).

[0058] Above each quartz lens (17), there is an LED lamp (19). The wavelength of the LED lamp (19) is 365mm. The six LED lamps (19) are controlled by a synchronous trigger (20). The six LED lamps (19) are installed in a suitable position above the quartz lens (17) to ensure that more excitation light shines through the quartz lens (17) onto the fluorescent powder press (4).

[0059] A first square hole of 5*5mm is opened at the center of the top of the first housing (15) to install a first short-pass filter (26). The first short-pass filter (26) has a size of 5*5*1.1mm, which allows light below 600nm to pass through and can effectively reduce the influence of blackbody radiation.

[0060] On the inner side of the first square hole below, a first single-board machine lens mount (27) is fixed with screws. A first single-board machine lens (28) is connected to the first single-board machine lens mount (27) to collect the fluorescence emitted by the fluorescent material.

[0061] On the outer side of the first square hole at the top, a first FC fiber mounting base (25) is fixed with screws. The first FC fiber mounting base (25) is connected to a second Y-type fiber (24) made of quartz. The light inlet port at one end of the second Y-type fiber (24) is set at the focal point of the first single-board camera lens (28) to ensure that more fluorescence is detected.

[0062] The other end of the second Y-type optical fiber (24) is connected to one end of the first Y-type optical fiber (21). At the connection between the second Y-type optical fiber (24) and the first Y-type optical fiber (21), a first narrowband filter (22) and a second narrowband filter (23) are coupled. The center wavelength of the first narrowband filter (22) is 458nm, the center wavelength of the second narrowband filter (23) is 497nm, and the bandwidth is 10nm.

[0063] The other end of the first Y-shaped optical fiber (21) is connected to a signal amplifier (12).

[0064] Replaceable device cover (7) suitable for fluorescence lifetime thermometry Figure 3 As shown, the whole is an inverted stainless steel container with a bottom thickness of 3mm, a bottom diameter of 18.5mm, a height of 18mm, and an outer shell shape of a second shell (29);

[0065] A 5*5mm square hole is opened at the center of the top of the second housing (29). A second short-pass filter (32) and a third narrow-band filter (33) are installed in the second square hole. Both of them are 5*5*1.1mm in size. The second short-pass filter (32) allows light below 600nm to pass through, which can effectively reduce the influence of blackbody radiation. The third narrow-band filter (33) allows light of the target peak wavelength to pass through.

[0066] On the inner side of the second square hole below, a second single-board machine lens mount (31) is fixed with screws. The second single-board machine lens mount (31) is connected to the second single-board machine lens (30) and is used to collect the fluorescence emitted by the fluorescent material.

[0067] On the outer side of the second square hole above, a second FC fiber optic mounting base (34) is fixed with screws. The second FC fiber optic mounting base (34) is connected to a quartz fiber (35). The light inlet of one end of the quartz fiber (35) is located at the focal point of the second single-board camera lens (30) to ensure that more fluorescence is detected. The other end of the quartz fiber (35) is connected to a signal amplifier (12).

[0068] A light shield (36) with an opening diameter of 48 mm and an outward extension of 50 mm is provided on the side of the second housing (29); the light outlet of the laser (37) is inserted into the light shield (36), and the laser wavelength is 355 nm; a reflector mounting base (39) is provided on the inner wall of the second housing (29), the reflector mounting base (39) is located in the inner cavity of the second housing (29), and a reflector (38) is provided on it. The light emitted by the laser (37) is irradiated onto the fluorescent powder press (4) at a certain angle through the reflector (38); the reflector mounting base (39) is used to fix and adjust the angle of the reflector (38).

[0069] The overall calibration process of the fluorescence intensity ratio thermometry method in this invention is as follows: six LEDs (19) are controlled by a synchronous trigger (20) to excite the fluorescent material of the fluorescent powder tablet (4). When the temperature is known, the fluorescence signals of the two target peak wavelengths are collected by the quartz optical fibers of the first Y-type optical fiber (21) and the second Y-type optical fiber (24). The ratio of fluorescence intensity is recorded by the information processing module consisting of a signal amplifier (12), a detector (13) and a host computer (14). By repeating the operation multiple times, a temperature-fluorescence intensity ratio relationship curve can be determined.

[0070] The overall calibration process of the fluorescence lifetime thermometry method in this invention is as follows: a laser (37) source emits a pulse excitation light to irradiate the fluorescent material of the fluorescent powder tablet (4). The fluorescent material is excited and produces fluorescence. When the excitation disappears, the fluorescence intensity decays rapidly. When the temperature is known, the fluorescence decay lifetime can be obtained by the information processing module consisting of signal amplifier (12), detector (13) and host computer (14). By repeating the operation multiple times, a temperature-fluorescence lifetime relationship curve can be determined.

[0071] The temperature can be determined by calculating the fluorescence intensity ratio / fluorescence lifetime based on the calibrated relationship curve.

[0072] The YAG:Dy fluorescent materials described in the above examples are intended to facilitate understanding and use of the invention by those skilled in the art. The invention is not limited to any particular fluorescent material or intermediate technology. Any changes or modifications to the above embodiments based on the design concept of this invention should be within the scope of protection of this invention.

[0073] Example 2

[0074] This embodiment provides a multifunctional measurement system based on fluorescence thermometry. The multifunctional measurement system includes: a temperature measurement environment based on a pit furnace, a fluorescent powder pellet, a signal processing unit, and a replaceable device cover; the pit furnace is equipped with a temperature control system, an atmosphere protection system, and a water cooling system; the signal processing unit includes a signal amplifier, a detector, and a host computer; the replaceable device cover has two modes, which are used to realize the intensity ratio method and the lifetime method for temperature measurement, respectively.

[0075] The well-type furnace adopts a top-opening design, which is more conducive to the installation of supporting devices. It can also simulate a vacuum or other gas environment through the gas extraction and filling function of the atmosphere protection system, and use K-type thermocouple temperature measurement data as a temperature control reference.

[0076] The fluorescent powder tablets are made using a fully automatic powder tablet press with a production pressure of 18.5 tons, a holding time of 20 seconds, and a finished product diameter of 40 mm and a thickness of 0.5 mm.

[0077] The phosphor is a self-synthesized YAG:Dy powder. By changing the synthesis conditions that affect the phosphor's luminescence performance, the performance of different samples was characterized (absorption spectrum, emission spectrum, etc.), and the sample with the optimal characterization results was obtained. The synthesis conditions for this sample were Dy doping. 3+ The ion concentration was 2 mol%, the flux LiF content was 10 wt%, and the firing time was 7 h.

[0078] The signal amplifier has a spectral range of 320-1060nm, a bandwidth of up to 500kHz, an input interface of FC, and remote control capability.

[0079] The detector can be selected from a variety of options. The recommended options are: for point detection, APD or PMT can be used, and for area detection, multi-channel high-speed camera or area array CCD camera can be used.

[0080] The replaceable device cover has two modes: Mode 1 uses 6 LEDs as the light source and is suitable for fluorescence intensity ratio temperature measurement; Mode 2 uses a pulsed laser as the light source and is suitable for fluorescence lifetime temperature measurement.

[0081] Mode 1 uses six or more synchronously triggered LEDs to compensate for the insufficient light power of a single LED, so that they are evenly distributed on the top of the device cover, ensuring that the light spots of all LEDs illuminate the same position of the fluorescent material.

[0082] Mode 2 uses a pulsed laser to excite the fluorescent material, with a pulse width of 1 ms and a period of 1 s.

[0083] Mode 1 uses two Y-shaped optical fibers as the transmission optical path, and two narrowband filters with different center wavelengths are coupled to the connection of the two optical fibers respectively, so as to allow the fluorescence signals of the two target peaks to pass through.

[0084] The aforementioned multifunctional measurement system based on fluorescence thermometry integrates temperature measuring devices based on intensity ratio and lifetime methods into a single system via a replaceable cover. Furthermore, the atmosphere protection system can simulate vacuum or other gaseous environments, truly achieving multiple uses from a single device.

[0085] Example 3

[0086] This embodiment uses a pit furnace as the testing environment for calibration experiments. Its vertical structure allows for easy installation of related auxiliary devices on its top. The pit furnace has a built-in temperature control system, providing a stable temperature field over extended periods. A water-cooling system is installed on top, significantly reducing the damage to the optical system at the openings caused by internal temperatures. Furthermore, the pit furnace can provide various gas or vacuum environments. Cylindrical fluorescent powder tablets with a diameter of 40mm and a thickness of 0.5mm were fabricated using a fully automatic powder press. Two interchangeable device covers were designed for use in intensity ratio and lifetime measurements, respectively. The overall design of this invention is a non-contact temperature measurement system, with a simple structure and comprehensive functions.

[0087] The technical solution of this embodiment is as follows: A multifunctional measurement system based on fluorescence thermometry includes a well furnace, a fluorescent powder pellet, a replaceable device cover, a light source, a lens, a filter, a reflector, an optical fiber, a signal amplifier, a detector, and a host computer; the well furnace has a top opening and is equipped with a temperature control system, a water cooling system, and an atmosphere protection system; the fluorescent powder pellet is adjusted to the center of the furnace cavity via a stage with good thermal conductivity; the replaceable device cover is a stainless steel container; the specific operation steps are as follows:

[0088] 1) A flange is installed at the opening on the top of the well-type furnace, and water-cooled pipes are installed around the flange; there are two pagoda nozzles on the top of the furnace, which are connected to the air extraction and air filling equipment respectively; the interior is heated by four silicon molybdenum rods, and a temperature control system based on K-type thermocouples is installed.

[0089] 2) The fluorescent powder tablet making instrument is a fully automatic powder tablet press, with a pressure set to 18.5 tons, a holding time of 20 seconds, a mold diameter of 40 mm, and a final fluorescent powder tablet thickness of 0.5 mm.

[0090] 3) The stainless steel container has a flange inside it and is fixed to the top of the furnace with screws; optical components such as light source, lens, filter, reflector, and optical fiber are integrated into the bottom of the 3mm thick stainless steel container; and a signal amplifier is connected through optical fiber.

[0091] 4) The signal amplifier is connected to the detector.

[0092] 5) The detector is connected to the host computer.

[0093] After completing the system setup steps 1), 2), 3), 4), and 5), a calibration experiment is conducted. At a known temperature, the relevant optical parameters are measured, and the temperature-fluorescence intensity ratio and temperature-fluorescence lifetime relationship curves are obtained through the calibration experiment. After obtaining the calibration curve, temperature measurement can be performed based on the curve.

[0094] The optical system involved must meet the principle of spectral matching, and the wavelength of the excitation light source must be consistent with the excitation wavelength of the phosphor; the filter only allows fluorescence at the target peak wavelength to pass through, reducing interference from other stray light; the optical fiber should have good transmission efficiency for light at the target wavelength; and the detector should have high response efficiency for fluorescence at the peak wavelength.

[0095] The essence of this invention is still based on the relationship between the luminescence characteristics of phosphor and temperature for temperature measurement. Therefore, the requirements for the optical path are relatively high. The entire optical path system adopts a closed structure, which can effectively avoid the influence of external light.

[0096] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A multifunctional measurement system based on fluorescence thermometry, characterized in that, The multifunctional measurement system includes: a well furnace (1) with its own temperature control system, a stage (3) located inside the well furnace (1), a replaceable device cover (7) that can collect fluorescence measurement information, and an information processing module that receives the fluorescence signal transmitted by the replaceable device cover (7). The well furnace (1) is used to simulate a real temperature measurement environment. It has a cylindrical well furnace cavity (2) inside, and a quartz window (9) is installed in the center of its upper part. The stage (3) is located at the upper center of the inner cavity (2) of the pit furnace, and a fluorescent powder press (4) is fixed on the upper surface of the stage (3). The replaceable device cover (7) is fitted around the quartz window (9) to excite the fluorescent material of the fluorescent powder tablet (4) to generate a fluorescent signal and to collect the fluorescent signal through an optical fiber. The information processing module includes a function to receive fluorescence signals transmitted back from the optical fiber, analyze and process the signal data, and obtain temperature measurement information. The information processing module includes a signal amplifier (12), a detector (13), and a host computer (14) connected in sequence. The signal amplifier (12) receives the fluorescence signal transmitted from the optical fiber and amplifies the signal. The signal amplifier (12) is connected to the detector (13), and the detector (13) is connected to the host computer (14) to analyze and process the signal data and obtain temperature measurement information. The replaceable device cover (7) is configured in different forms according to different fluorescence thermometry methods, including: fluorescence intensity ratio thermometry and fluorescence lifetime thermometry. Among them, the replaceable device cover (7) for the fluorescence intensity ratio thermometry method is an inverted stainless steel container, and the outer shell is the first outer shell (15). The first outer shell (15) has several evenly distributed circular holes around its top; a pressure ring (18) is provided at each circular hole, and the pressure ring (18) is used to connect the lens sleeve (16). A quartz lens (17) is fixed inside the lens sleeve (16) by a retaining ring. The quartz lens (17) can be focused by adjusting the position of the lens sleeve (16). Above each quartz lens (17), there is an LED lamp (19). Several LED lamps (19) are controlled by a synchronous trigger (20). The LED lamps (19) are installed in a suitable position above the quartz lens (17) to ensure that the excitation light of more LED lamps (19) shines on the fluorescent powder press (4) through the quartz lens (17). A first square hole is opened at the center of the top of the first housing (15) to install a first short-pass filter (26). The first short-pass filter (26) allows light below 600nm to pass through in order to reduce the influence of blackbody radiation. On the inner side of the first square hole below, a first single-board machine lens mount (27) is fixed, and a first single-board machine lens (28) is connected to the first single-board machine lens mount (27) for collecting the fluorescence emitted by the fluorescent material; On the outer side of the first square hole above, a first FC fiber mounting base (25) is fixed. The first FC fiber mounting base (25) is connected to a second Y-type fiber (24). The light inlet port at one end of the second Y-type fiber (24) is set at the focal point of the first single-board camera lens (28) to ensure that more fluorescence is detected. The other end of the second Y-type optical fiber (24) is connected to one end of the first Y-type optical fiber (21), and the connection between the second Y-type optical fiber (24) and the first Y-type optical fiber (21) is coupled with a first narrowband filter (22) and a second narrowband filter (23). The other end of the first Y-type optical fiber (21) is connected to a signal amplifier (12); The replaceable device cover (7) for the fluorescence lifetime thermometry method is an inverted stainless steel container with a second outer shell (29). A second square hole is opened at the center of the top of the second housing (29). A second short-pass filter (32) and a third narrow-band filter (33) are installed in the second square hole. The second short-pass filter (32) allows light below 600nm to pass through, effectively reducing the influence of blackbody radiation. The third narrow-band filter (33) allows light of the target peak wavelength to pass through. A second single-board camera lens mount (31) is fixed on the inner side of the second square hole below. The second single-board camera lens mount (31) is connected to the second single-board camera lens (30) and is used to collect the fluorescence emitted by the fluorescent material. A second FC fiber optic mounting base (34) is fixed on the outer side of the second square hole above. The second FC fiber optic mounting base (34) is connected to a quartz fiber (35). The light inlet of one end of the quartz fiber (35) is located at the focal point of the second single-board camera lens (30) to ensure that more fluorescence is detected. The other end of the quartz fiber (35) is connected to a signal amplifier (12). An outwardly extending light shield (36) is provided on the side of the second housing (29); the light outlet of the laser (37) is inserted into the light shield (36); a reflector mounting base (39) is provided on the inner wall of the second housing (29), the reflector mounting base (39) is located in the inner cavity of the second housing (29), and a reflector (38) is provided on it. The light emitted by the laser (37) is irradiated onto the fluorescent powder press (4) at a certain angle through the reflector (38); the reflector mounting base (39) is used to fix and adjust the angle of the reflector (38).

2. The multifunctional measurement system based on fluorescence thermometry as described in claim 1, characterized in that, The well furnace (1) is equipped with an air inlet (5), a water inlet (6), a flange (8), a quartz window (9), a water outlet (10), and an air extraction port (11). The top of the pit furnace (1) has a round hole for mounting the flange (8); the center of the flange (8) has a hole for mounting a quartz window (9); the gas inlet (5) and the gas outlet (11) are located on both sides of the top of the pit furnace (1) to keep the furnace in a vacuum or protective gas environment; the water inlet (6) and the water outlet (10) are the two ends of the water cooling device to effectively reduce the damage of the high temperature environment inside the furnace to other supporting equipment inside the pit furnace (1).

3. The multifunctional measurement system based on fluorescence thermometry as described in claim 1, characterized in that, The detector (13) is selected differently according to different test requirements. For point temperature testing, avalanche photodiodes and photomultiplier tubes are selected; for surface temperature measurement, area array CCD cameras and multi-channel high-speed cameras are selected.

4. The multifunctional measurement system based on fluorescence thermometry as described in claim 1, characterized in that, The stage (3), which has good thermal conductivity, is placed in a high-temperature environment to adjust the position of the fluorescent powder press (4), ensuring that the fluorescent powder press (4) is heated more evenly and the referenced temperature control value is more reliable.

5. The multifunctional measurement system based on fluorescence thermometry as described in claim 1, characterized in that, The overall calibration process of the fluorescence intensity ratio thermometry method is as follows: several LEDs (19) are controlled by a synchronous trigger (20) to excite the fluorescent material of the fluorescent powder tablet (4). When the temperature is known, the fluorescence signals of the two target peak wavelengths are collected by the quartz optical fibers of the first Y-type optical fiber (21) and the second Y-type optical fiber (24). The ratio of fluorescence intensity is recorded by the information processing module consisting of the signal amplifier (12), the detector (13) and the host computer (14). By repeating the operation multiple times, a temperature-fluorescence intensity ratio relationship curve can be determined. Based on the calibrated relationship curve, temperature measurement information can be obtained by calculating the fluorescence intensity ratio.

6. The multifunctional measurement system based on fluorescence thermometry as described in claim 1, characterized in that, The overall calibration process of the fluorescence lifetime thermometry method is as follows: a laser (37) source emits a pulse excitation light to irradiate the fluorescent material of the fluorescent powder pellet (4). The fluorescent material is excited and generates a fluorescence signal. When the excitation disappears, the fluorescence intensity decays rapidly. When the temperature is known, the fluorescence decay lifetime can be obtained through the information processing module composed of signal amplifier (12), detector (13) and host computer (14). By repeating the operation multiple times, a temperature-fluorescence lifetime relationship curve can be determined. Temperature measurement information can be obtained by calculating the fluorescence lifetime based on the calibrated relationship curve.

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