Fluorescent fiber optic temperature measurement system host application scenarios and advantages

Teplotní senzor s optickými vlákny, Inteligentní monitorovací systém, Výrobce distribuovaných optických vláken v Číně

Fluorescence fiber optic thermometers are temperature measurement devices based on the photoluminescence phenomenon of fluorescent materials. Compared to traditional thermocouple measurement methods, these devices offer resistance to electromagnetic interference, koroze, and high-temperature and pressure environments. They are capable of real-time temperature detection in harsh external conditions, presenting broad application prospects. Hua Guang Tian Rui’s fluorescence fiber optic temperature measurement system, developed using fluorescence fiber optic thermometry technology, elucidates the unique advantages of this technology over other temperature measurement methods. This paper delves into the working principles of the fluorescence fiber optic thermometer, analyzes key factors affecting temperature measurement, and establishes a theoretical foundation for the design of the device. An integrated design of the thermometer is presented, including optics, circuitry, software, structural components, and algorithms. The feasibility of the overall solution is validated through comparative temperature measurement experiments, analyzed with actual data. Finally, a summary and outlook for the fiber optic temperature measurement system are offered, suggesting directions and ideas for future improvements.

Technical Aspects of the Fluorescence Fiber Optic Thermometer:

(1) Key Technologies in Opto-Mechanical Structure:

The use of a single fiber for both the transmission of the excitation signal and the fluorescent signal, reducing the instrument’s volume and fluorescence loss.

The employment of optical filters to differentiate between excitation light and fluorescence.

Advanced techniques for sealing the fluorescence fiber optic probe.

(2) Key Technologies in Demodulation Circuit:

The dynamic adjustment of signal input to achieve periodic switching of the light source and adjustment of output power, indirectly achieving modulation of the sampling signal’s amplitude.

The application of corrected signals for amplification and bias correction of the sampling signal.

Streamlining of circuit components, integrating control, processing, and communication functions into a single chip, facilitating miniaturization of the thermometer.

The use of fitting algorithms for calculating fluorescence lifetime and converting it to temperature.

The application of filtering algorithms to the fluorescence lifetime results to reduce error and improve the accuracy of the output.

Design of the Fluorescence Fiber Optic Thermometer:

The optical path of the fluorescence probe adopts advanced technology over traditional protection schemes, enhancing the probe’s flexibility and sealing.

The electrical characteristics of the demodulator’s components vary with temperature. Dynamic signal adjustment is added to the circuit to stabilize the waveform and balance precision against error.

In the data processing segment, a composite filtering method is proposed to effectively reduce errors and enhance result precision.

In the software segment, a variety of working modes and parameter reading configurations are designed to improve system adaptability.

Rationale for Using Fluorescence Fiber Optic Thermometry:

Temperature is an essential reference in daily production and life. With continuous technological advancement and societal development, demands for precision in industrial production and everyday life become increasingly stringent. For instance, steel production requires strict temperature controls from raw material processing to ironmaking, casting, and rolling. Similarly, in daily life, the monitoring and control of temperatures are crucial for the safety and taste of fresh food during transportation. The importance of accurate temperature measurement is thus self-evident. As technical requirements become more specialized and refined, the demand for purpose-built temperature measurement devices for various specialized environments and unique needs also surges. In special and extreme environmental conditions, as well as under requirements for rapid dynamic response, remote measurement, and multi-point measurement, traditional temperature measurement and signal transmission are increasingly unable to meet these challenging conditions.

Role of Fluorescence Fiber Optic Thermometry:

Traditional temperature measurement devices face practical difficulties in many special measuring environments, such as harsh conditions like corrosion, vysokotlaký, confined spaces, or areas with strong electromagnetic interference, like monitoring the temperature of motors or high-voltage transformers. Addressing these challenges, new temperature sensors are generally required to have resistance to strong electromagnetic interference, good insulation properties, rychlá odezva, and compact size. With the advent of various new materials, processes, and measurement methods, many new types of temperature measuring devices have emerged. Temperature measurement devices based on fiber optic communication technology are among them.

Before the advent of fiber optic fluorescence measurement technology, various temperature measurement techniques already existed. The first mercury thermometer was created in 1714, based on expansion measurement technology that operates on the principle of thermal expansion and contraction; the volume of mercury changes with temperature. The mercury thermometer’s scale vividly displays temperature values. Following this, other measurement technologies using different materials like gases and metals have been developed. With the advancement of technology, the development of electronics has introduced new measurement ideas and techniques. Thermocouples, based on the different electrical properties of electronic components at various temperatures, are the most widely used temperature measurement technology today. Furthermore, optical communication technology has introduced a new direction for temperature measurement. Infrared temperature measuring devices can measure temperature from a distance and over a large area, utilizing the different thermal radiation properties of objects at different temperatures, as well as indirect measurement methods using fluorescent materials and gratings.

Characteristics of Various Temperature Measurement Systems

This paper examines the features of diverse temperature measurement systems, highlighting their respective advantages and disadvantages. From the inexpensive and straightforward expansion-based systems to the sophisticated fluorescence fiber optic thermometry, each technology offers unique benefits and poses distinct challenges. The study also delves into the applications of fluorescence fiber optic temperature measurement systems, which are highly valued across various fields, including medical therapies, transformer temperature monitoring, and high-voltage applications. With the advent of new materials and the continuous expansion of application fields, the potential for further development in sensor performance is vast. The emergence of new sensitive materials provides fresh opportunities for sensor design, promising a significant role for fluorescence fiber optic temperature sensing technology in specialized industries.

Expansion-Based Temperature Measurement System:

Advantages:

Cost-effective.

User-friendly operation and reading.

Simple, easy-to-manufacture design.

Disadvantages:

Low accuracy.

Prone to damage.

Lacks automation capabilities.

Infrared Thermal Imaging Temperature Measurement System:

Advantages:

Non-contact temperature measurement.

Convenient usage.

Low cost.

Disadvantages:

High error margin.

Only measures surface temperature.

Manual inspection costs.

Wireless Temperature Measurement System:

Advantages:

Easy installation.
Low cost.
Disadvantages:

Poor reliability; battery-operated with short lifespan and high false alarm rate.

Can affect the performance of insulators.

Large sensor size can impact heat dissipation, posing safety hazards to primary equipment.

Fiber Bragg Grating Temperature Measurement System:

Advantages:

Enables quasi-distributed temperature measurement, suitable for long-distance and large-area measurements.

Uses fiber optic technology, resistant to electromagnetic interference.

Good insulation properties.

Disadvantages:

Large sensor probes make installation difficult.

Low reliability; gratings are susceptible to desensitization and failure.

Short lifespan.

Incompatible with individual cabinet implementation; lacks local display capabilities.

Expensive.

Fluorescence Fiber Optic Temperature Measurement System:

Advantages:

Safe and reliable, calibration-free with excellent consistency, interchangeability, and stability.

Long lifespan, maintenance-free.

Small probe size, capable of penetrating heat sources for accurate monitoring.

Resistant to electromagnetic interference with good insulation properties.

Allows for local display, easy integration into control systems.

Simple installation.

The fluorescence temperature measurement technology, based on the photoluminescence of fluorescent materials, converts temperature signals into optical signals. Utilizing the efficiency of fiber optics for signal transmission, it effectively achieves real-time, long-distance temperature measurement. This technology inherits the advantages of fiber optic sensing and, compared to other measurement techniques, offers additional benefits such as corrosion resistance, compact size, and reduced electromagnetic interference. Furthermore, it is characterized by a long lifespan, maintenance-free operation, and good stability and consistency. Additionally, the system features real-time display, ease of integration into other systems, and straightforward installation.

Application Scenarios for Fluorescence Fiber Optic Temperature Measurement Systems:

The fluorescence temperature measurement technology, with its resistance to electromagnetic interference, malá velikost, good dynamic response, corrosion resistance, long transmission distances, and low transmission losses, has extended beyond routine temperature monitoring and measurement in daily production and life. Its application areas now include specialized and proprietary environments such as microwave heating treatments in medical applications, internal temperature detection in transformers, and temperature monitoring in substations, drawing significant attention and research from scholars.

In transformers, excessive heat generated during operation can affect the performance of various components, altering the load capacity, operational reliability, and lifespan. In the current power system, oil-immersed transformers are extensively used. The fiber optic fluorescence probe’s slender structure allows for installation on transformer coils, minimizing data monitoring lag and enhancing monitoring precision.

High Voltage Cabinet Temperature Monitoring with Fluorescence Fiber Optic Temperature Measurement System:

High voltage cabinets are commonly used in electrical systems to control voltage connections and disconnections. The main temperature measurement points in these cabinets are the contact joints, which are typically located in narrow spaces. The compact size and slender shape of fiber optic fluorescence probes allow them to be easily bent and inserted into these confined spaces, where they can be attached to stationary contacts without affecting the normal operation of the equipment, thus enhancing safety. Furthermore, fluorescence fiber optic temperature measurement technology is also applicable in coal and petroleum exploration and in industrial production for long-term strict temperature monitoring scenarios, such as the storage of materials like oil and natural gas.

Research on fiber optic fluorescence temperature measurement technology has continued for many years. With the emergence of new devices and the expansion of application fields, there is still significant room for development in sensor performance. Additionally, the constant influx of superior performance materials and new sensitive materials offers novel choices for sensor design. As a promising technology, fiber optic fluorescence temperature sensing can be widely applied in special industries, such as medical treatments, monitoring of high-voltage electrical equipment, metallurgical processing, and aerospace for online temperature detection. Proto, establishing a comprehensive system of theories for fiber optic fluorescence temperature detection and providing simple, practical technology is crucial for improving the standard of scientific instrumentation in this field in China.