What is a fluorescence fiber thermometer

Sensor de temperatura de fibra òptica, Sistema de monitorització intel·ligent, Fabricant de fibra òptica distribuïda a la Xina

Principi de Fluorescent Fiber Optic Thermometer

Fluorescent fiber optic thermometer is a temperature measurement device based on the photoluminescence phenomenon of fluorescent materials. Compared with traditional thermocouple measurement methods, it has advantages such as anti electromagnetic interference, resistència a la corrosió, and high temperature and high pressure resistance. It can achieve real-time temperature detection in more harsh external environments and has broad application prospects. The current development status of fluorescence fiber optic temperature measurement technology at home and abroad is described, and the unique advantages of fluorescence fiber optic temperature measurement technology compared to other temperature measurement methods are elaborated. By introducing the working principle of fluorescence fiber optic temperature measurement instrument and analyzing the key factors affecting temperature measurement, a theoretical basis is established for the design of fluorescence fiber optic temperature measurement instrument. Aleshores, the overall design of the fluorescent fiber thermometer was carried out, including the optical path, circuit, software, structure, and algorithm. To verify the feasibility of the overall plan, a comparative experiment of temperature measurement was designed, and the overall plan was analyzed and studied based on actual data. The fiber optic temperature measurement system has been summarized and discussed, and future directions and ideas for improving fiber optic temperature measurement have been proposed.

The technology of fluorescent fiber thermometer:

(1) The key technologies of optical mechanical structure include: using a single optical fiber to simultaneously transmit light source signals and fluorescence signals, reducing the volume and fluorescence loss of fluorescence fiber thermometers; Using multiple filters to screen excitation light and fluorescence; Using high-temperature melting technology to achieve sealing of fluorescent fiber optic probes.

(2) The key technology of demodulation circuit includes: using rectangular wave signal and voltage dynamic adjustment signal as two inputs to achieve periodic switching of light source and output power adjustment, indirectly achieving amplitude adjustment of sampling signal; Using differential amplification circuits and differential correction signals to amplify sampling signals and correct biases; Simplify circuit components and integrate control, processing, communication and other functions into one chip, which is conducive to the miniaturization of fluorescence fiber thermometers; Adopting the least squares fitting algorithm and using voltage signals instead of light signals to calculate fluorescence lifetime and convert temperature; Filter the fluorescence lifetime results using a filtering algorithm to reduce errors and improve the accuracy of the output results.
Design of Fluorescent Fiber Optic Thermometer:

 

1、 The fluorescent probe part of the optical path adopts high-temperature melting sealing instead of traditional probe protection schemes such as metal protective covers or heat shrink tubes, which increases the flexibility and sealing effect of the probe;

2、 The electrical characteristics of some components in the demodulator vary with temperature. To reduce the impact of this part on signal demodulation, a dynamic adjustment signal is added to the circuit to adjust the stability of the signal waveform, balance waveform accuracy and error;

3、 The data processing section proposes a combination filtering method for data processing, which effectively reduces errors and improves the accuracy of output results;

4、 The software part is designed with multiple working modes and parameter reading and configuration functions to improve the adaptability of this system.

Why use fluorescent mesura de temperatura de fibra òptica:
Temperature is an important reference quantity in daily production and life, and with the continuous advancement of technology and the development of human society, people have increasingly high requirements for temperature in daily industrial production and daily life. In the field of industrial production, steel production, from raw material processing, ironmaking to mold casting, steel rolling, etc., has strict temperature control. Per exemple, the preservation and transportation of fresh food in daily life, as well as temperature monitoring and control, have a significant impact on food safety and taste. Per això, the importance of accurate temperature measurement is self-evident. Al mateix temps, in the face of increasingly specialized technical requirements classification and continuous refinement of technical conditions, corresponding measurement equipment and measurement technology classification are also increasing, and the demand for temperature measurement devices designed for various specialized environments and special requirements is constantly emerging. Under special circumstances and extreme environmental conditions, as well as different requirements such as fast dynamic response, remote measurement, and multi-point measurement, traditional temperature measurement and signal transmission have become increasingly difficult to meet different demanding conditions, and the difficulty of implementation has also increased.

 

Fluorescence fiber optic temperature measurement function:

Actualment, traditional temperature measurement equipment has some practical difficulties in use in many special measurement environments, such as the harsh environment of the temperature measurement point, such as corrosion, Alta tensió, narrow space, etc., or the strong electromagnetic interference in the area where the measurement point is located, such as temperature monitoring of motors and high-voltage transformers. In response to the above difficulties, most new temperature sensors need to have advantages such as strong electromagnetic interference resistance, good insulation performance, fast response, and small size. With the application of various new materials and processes, as well as the exploration of new measurement methods, a variety of new temperature measurement devices have emerged. One of them is temperature measurement equipment based on fiber optic communication technology.

 

Before the birth of fiber optic fluorescence measurement technology, there were already various temperature measurement techniques. The first mercury thermometer was born as early as 1714. Mercury thermometers belong to the expansion measurement technology, which utilizes the principle of thermal expansion and contraction, and the space occupied by mercury volume varies with different temperatures. The scale of a mercury thermometer vividly displays the numerical value of temperature. Based on this principle, in addition to liquids, measurement technologies for different materials such as gases and metals have also emerged in the future. With the continuous advancement of technology, the vigorous development of electricity has brought new measurement ideas and technologies. Thermocouple technology is based on the different electrical properties of electronic components at different temperatures, and is currently the most widely used and diverse temperature measurement technology. A més, optical communication technology has also pointed out a new direction for temperature measurement. Infrared temperature measurement devices made using the different characteristics of thermal radiation of objects at different temperatures can achieve temperature measurement over long distances and large ranges, as well as indirect temperature measurement methods using intermediate devices such as fluorescent materials and gratings.

 

Characteristics of temperature measurement system

Expansion temperature measurement system

1. Low price 2. Convenient operation and reading 3. Simple and easy to manufacture mechanism

1. Low accuracy 2. Easy to damage 3. Cannot achieve automation

Infrared thermal imaging temperature measurement system

1. Non contact temperature measurement 2. Easy to use 3. Low cost 1. Large error

2. Can only measure surface temperature. 3. Cost of manual inspection

Wireless temperature measurement system

1. Easy installation 2. Low cost

1. Poor reliability, carrying batteries, short lifespan, high false alarm rate

2. Affects the performance of insulators

3. The large volume of sensors affects heat dissipation and poses a safety hazard to primary equipment

Fiber Bragg Grating Temperature Measurement System

1. It can achieve quasi distributed temperature measurement, suitable for long-distance and large area measurement

2. Adopting fiber optic technology to resist electromagnetic interference

3. Good insulation performance

 

1. The sensor probe is large and difficult to install

2. Low reliability, grating is prone to desensitization and failure

3. Short lifespan

4. Unable to achieve single cabinet matching and on-site display

5. Expensive price

Advantages of Fluorescent Fiber Optic Temperature Measurement System

1. Safe and reliable, can achieve calibration free, with good consistency, interchangeability, and stability

2. Llarga vida útil, sense manteniment

3. The probe has a small volume and can penetrate deep into the hot spot to achieve true monitoring

4. Anti interferències electromagnètiques, good insulation performance

5. It can achieve on-site display, making it easy to integrate into the operating system

6. Easy installation

Fluorescence temperature measurement technology converts temperature signals into optical signals based on the photoluminescence phenomenon of fluorescent materials, and utilizes the high efficiency of optical fiber in optical signal transmission to effectively achieve real-time and long-distance temperature measurement. Fiber optic fluorescence measurement technology inherits the advantages of fiber optic sensing technology. Compared with other temperature measurement technologies, it not only has the characteristics of corrosion resistance, good insulation, and small size, but also effectively reduces electromagnetic interference. Meanwhile, fiber optic fluorescence measurement technology also has the characteristics of long lifespan, sense manteniment, good stability, and consistency. A més, this system also features real-time display, easy integration into other systems, and convenient installation.