Tag: FBG sensors

Fiber Bragg grating sensors for overhead transmission lines’ monitoring

Fiber Bragg grating sensors have a wide range of applications starting from the oil & gas industry and ending with structural health monitoring. However, few people know that FBG sensors are also effectively used to prevent icing on the overhead transmission lines.

According to the statistics, many countries have already faced great accidents and vast economic loss caused by the icing on the overhead transmission lines. The frequent icing load can lead to catastrophic consequences, for example, line breaks, short circuits, and tower collapses. In such disasters, thousands of people find themselves without electricity.

Fiber optic sensors VS electric ones in icing monitoring

Nowadays, there are different technologies for icing monitoring that can be produced both for individual transmission lines and for the whole energy transport infrastructure. The common ways of icing conditions estimation are dip-sag monitoring, video surveillance, non-contact infrared measurement, etc. All these methods usually can’t give accurate data on icing thickness, and they have got difficulties because of electromagnetic interference with the power supply.

Compared to the traditional sensors, fiber optic sensors improve the effectiveness of accident prevention through monitoring and control with the help of automated instruments and systems.

The main system’s features in icing monitoring are:

The system monitors the onset of icing in accordance with changes in the load and sag of the span.
The system includes an ice melting system.
The system monitors the temperature of the ground wire and switches the melting off automatically.

FBG sensors’ main advantages for icing monitoring

In fact, fiber Bragg grating (FBG) sensors have already turned out to be an excellent solution for solving all the issues where electric sensors failed. In comparison with them, fiber optic sensors apply light for change monitoring in strain, temperature, and other parameters. It means that their accuracy doesn’t depend on electromagnetic interference.

Over recent years, FBG sensors have proved to have a lot of potential in monitoring the transmission lines. Fiber Bragg grating (FBG) sensors’ advantages are:

compact size,
lightweight,
tolerance to corrosion and to electromagnetic interference,
resistance to the environmental impact,
high-temperature stability,
explosion and fire safety,
wide range of measurements, etc.

Scientists made FBG sensors able to define the accurate phase without a special reference point. Moreover, they can also suit for grid monitoring and distributed measurement.

Thanks to modern measurement methods such as distributed fiber optic sensors, a complex problem of monitoring the start of the ice formation can be solved, and there is the most effective way to eliminate it.

Optromix is a fast-growing vendor of fiber Bragg grating (FBG) product line such as fiber Bragg grating sensors, for example, fbg strain sensors, FBG interrogators and multiplexers, Distributed Acoustic Sensing (DAS) systems, Distributed Temperature Sensing (DTS) systems. The company creates and supplies a broad variety of fiber optic solutions for monitoring worldwide. If you are interested in structural health monitoring systems and want to learn more, please contact us at info@optromix.com

Fiber Bragg Grating (FBG) sensors for railway monitoring

For the last decade, fiber Bragg grating (FBG) sensors have been attracting more attention from scientists all over the globe thanks to their numeral benefits. Nowadays, they are widely applied in health monitoring, aerospace, civil engineering, oil & gas, smart structures, etc. In this article, we will consider FBG sensors for one of the most used transportation systems, for railways.

FBG sensors in railway transport systems

Railway transport systems have faced a range of difficulties such as longer service availability, providing high safety levels, reduced energy consumption, and optimal operation. Monitoring systems should meet all of these tasks without interruption.

According to many successful pieces of research, fiber optic technology can provide all these aspects at once, it can be applied to ensure railway monitoring. It is important to understand the structural and operating conditions of rails and freight and passenger service cars to provide safe and reliable work.

The point is that FBG sensors have many crucial characteristics that perfectly suit railways’ operational conditions. For instance, it is a very long-range interrogation, that is better, especially in comparison with usual electrical sensors. Fiber Bragg Grating sensors are the only sensors that measure all the data and offer it in real-time. FBGs also are low susceptible to fluctuations. Moreover, they can be interrogated from any end.

All these features are especially significant for the railways in providing safe operations. In addition to that, FBGs are universal and can be applied for measuring many other parameters like inclination and acceleration over a large area.

Recent programs with fiber Bragg grating sensors

The most recent project where Fiber Bragg Grating sensors are involved is taken place in India. The main goal is to make the railways there safer with the help of fiber optic technology. Specialists have used sensing technology to reduce travel time and increase the trains’ speed between two states. The railway construction will be conducted by a developed structural health monitoring system.

Thanks to monitoring systems based on fiber optic solutions, rail corporations could easily get real-time data about rail structures’ conditions within 24 hours. Therefore, this feature will fast the warning alerts for possible damage detection. The fiber optic technology can be configured for any type of location and structure, even in vulnerable areas. It is specially referred to as earth slip locations, heavy rainfall areas, etc. However, recently only routine manual inspection is carried out in such cases. Constant monitoring with the FBG sensors will provide real rail safety in such areas.

The government considers that the potential of fiber Bragg grating (FBG) sensors is huge and can be applied in other projects on rail safety. It allows finding the structural defects out as early as possible, not only when an accident occurs. The preventative work gives an opportunity to avoid many troubles and mass casualties that happen.
All in all, thanks to constant real-time monitoring, timely warning alerts, and the possibility of applying in severe environmental circumstances, specialists can use fiber optic technology in many spheres, as well as railways.

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Fiber Optic Technology in earthquake monitoring

The improvement of life quality is the main factor in the development of every new technology including fiber optic technology. Scientists from all over the world have always looked for new solutions for the prevention of seismic events, which is one of the most essential points in life quality improvement.

Seismic data of the previous years, electric sensors, fiber Bragg grating sensors, and modern distributed acoustic sensing have an aim to predict all catastrophes connected to earthquakes in the future. Especially, it concerns areas with high rates of population. More accurate monitoring gives an opportunity to reduce the risks resulting from most common natural events like earthquakes, landslides, eruptions, etc.

FBG sensors in the prediction of seismic events

In the past, the only approach to all the natural phenomena was the information about the cases. Then electric sensors were applied. However, usual electric sensors are hard to comply with the monitoring requirements of high sensitivity and long lifetime. That is why scientists have tried to use different FBG sensors. In fact, fiber Bragg grating temperature sensors were produced for better monitoring and observation of seismic activity. Except for fiber Bragg grating temperature sensors, there are FBG strain sensors that can be also applied for collecting data as geothermal monitoring.

In comparison with the usual electric sensors, FBG sensors can offer ease in signal transmission and immunity to electromagnetic interference that plays an important role. In fact, temperature monitoring with the help of the FBG is considered to be one of the most popular applications. Moreover, modern sensors can be sensitive to both strain and temperature.

Distributed Acoustic Sensing in earthquake prediction

If we speak of seismic activity and the prediction of seismic events, we should definitely mention another fiber optic technology that helps in geothermal monitoring called distributed acoustic sensing. DAS systems are widely applied in various spheres, including vibroacoustic monitoring of the oil wells.

Scientists have already held a number of experiments with the help of the distributed acoustic sensing studying seismic activity in different areas such as metropolitan, oceans, etc. The results prove that DAS systems are able to accurately detect vibrations even in conditions of a highly noisy environment and far away from the epicenter. That’s why this fiber optic technology draws the attention of many researchers and is popular where there is a need for precise and robust information. The DAS’s improved performance has shown its potential to be a powerful instrument in geophysics studies thanks to its bandwidth, waveform fidelity, cost-effectiveness, and simplicity.

Despite all the achievements in fiber optic technology, scientists still consider that DAS technology for seismic monitoring is still in its infancy. However, they are sure that such promising opportunities will play a crucial role in the next seismic networks.

Optromix is a DAS system manufacturer that provides top-of-the-line distributed acoustic sensing systems suitable for monitoring commerce networks. If you have any questions or would like to buy a DAS system, please contact us at info@optromix.com

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Fiber Bragg Grating (FBG) Sensors for Industrial Sensing

Recently, researchers have presented a new generation of fiber Bragg grating (FBG) sensors that are covered with aluminum and copper. These FBG sensors are compact and hermetically sealed. Depending on the applied coating, they are resistant to high or low temperatures and can be applied in harsh environmental conditions. As well as gold-coated fiber Bragg grating sensors, they are representatives of a modern generation of humidity-proof different sensors, for example, temperature sensors, strain sensors, pressure sensors, etc.

Main Fiber Bragg Grating Sensors advantages

It’s a well-known fact that FBG sensors are widely applied in various fields and spheres thanks to their advantages. A lot of measurements in harsh environmental conditions would become possible by the usage of fiber optic technology.

Here are the most common advantages of fiber Bragg grating sensors:

absolute temperature and other measurements in comparison with usual electric sensors;
rapid linear response in strain, pressure, or temperature measurements;
the compact size of the construction reduces the weight and allows to use of many sensing points on a single fiber strand;
measurements over long distances;
acceptable price, etc.

The new type of FBG Sensors

However, a usual FBG sensor with the glass fiber coating can have several limitations because of the high humidity, high temperatures, corrosion, etc. The new type of Fiber Bragg Gratings are embedded into optical fibers coated with aluminum, copper, or gold have much more applications.

Scientists have offered processes that allow providing two lays of metal coatings. It gives an opportunity to create different lengths of window stripping and make the second layer with the needed thickness and length.

In conclusion, we must say that scientists from all over the world keep finding new fiber optic solutions to solve the modern problems we face in real life. That means that fiber optic technology will be better and more effective every day.

Optromix is a fast-growing vendor of fiber Bragg grating (FBG) product line such as fiber Bragg grating sensors, for example, FBG strain sensors, FBG interrogators and multiplexers, Distributed Acoustic Sensing (DAS) systems, Distributed Temperature Sensing (DTS) systems. The company creates and supplies a broad variety of fiber optic solutions for monitoring worldwide. If you are interested in structural health monitoring systems and want to learn more, please contact us at info@optromix.com

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Fiber Optic Technology for corrosion detection

It is a well-known fact that fiber optic technology has a wide range of applications in different spheres, starting from medicine and ending with 3D visualization. In particular, it is applied in the oil and gas industry where Fiber Optic Technology solves several issues, including corrosion detection.

Corrosion impact and Fiber Optic Technology

Corrosion is the deterioration of the metal because of its being under exposure to electrochemical molecules that damage its surface and lead to other worse changes. It has already become a real problem for the oil and gas industry. According to the research in 2015, the annual cost amounted to $500,000 in the US. That’s a six-time bigger than the budget for natural disasters. In fact, 33 percent of the cases occurring in the gas and oil industry are connected to corrosion.

That is why scientists from all over the world are looking for new ways to solve the corrosion problem by using modern fiber optic solutions. There are several methods of corrosion detection, but fiber optic technology is still considered to be one of the most cost-effective ones.

FBG sensors to Detect Corrosion

Thanks to modern scientifically developed alloys, the number of corrosion cases has declined. However, there are still challenges connected to contaminating fluids that come into contact with the metals and accelerate the corrosion process. This can definitely lead to the compromising of the structures and lives of the wells over time.

Fiber Bragg grating sensors and distributed sensing systems are considered to be some of the most cost-effective instruments that are created to locate corrosion at an early stage. Distributed sensing pipeline leak detection systems can be divided into two types: distributed acoustic sensing (DAS) or distributed temperature sensing (DTS). They are considered to be the most successful systems and are widely applied in many projects across tens of thousands of kilometers of pipelines.

That’s why FBG sensors are widely applied for corrosion detection in pipes. Fiber Bragg grating sensors transmit the data about the whole picture of the pipe’s integrity. So the corrosion can be noticed at the early stage at different levels. Thanks to the fiber optic technology, it is possible to reduce the detection period and the company losses because of the corrosion cases. Actually, the majority of gas and oil pipelines lie in urban wetlands, mountains, and forests that are the perfect environment for corrosion. And most of the pipes were not prepared for it.

That is why scientists have used the best advantages of distributed sensing to apply the FBG sensors as data lines and detectors. These FBG sensors are constantly reading the internal pipe material conditions caused by corrosion. The Fiber Bragg grating sensors read the thickness of the pipe and transmit the information to the center. They even have the ability to warn when the pipe drops below a 3 mm thickness. Moreover, FBG sensors help in detecting internal changes and events like flow constrictions and liquid accumulations. They can easily detect changes in temperature, noise, and vibration.

All in all, we must conclude that Fiber Bragg grating sensors rank among the most effective corrosion detection methods that allow solving the problem in time.

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Fiber Optic Solutions for fusion power plants

According to the researchers from the American university, the faster specialists can detect thermal shifts the faster they can prevent disruptive quench in the HTS magnets for fusion devices in power plants. That is why scientists hope to solve this issue with the help of newly developed fiber optic solutions.

Recently, fusion became considered a safe, constant, and carbon-free energy source. The HTS magnets play a crucial role in many such programs. It increases the necessity of different instruments such as sensors and controls that help magnets to work in severe environmental conditions of a fusion power plant.

The research team had an aim to prevent quenches in power plants that are based on magnetic-confinement fusion devices. Scientists also focused on the commercialization, availability, and simplicity in the conditions of the accelerating fusion’s viability as an energy source. They aimed to create a fiber optic system that would provide minimal risks and would be robust.

Scientists used optical fibers with fiber Bragg gratings (FBGs) as a promising instrument that can measure temperature. FBG reflects just one of the wavelengths that are determined by the spacing while most of the light passes through. The reflected wavelength can demonstrate the small differences in temperature and strain. That is why the installation of fiber Bragg gratings along the fiber optic cable can help in temperature monitoring all over the length.

FBGs have been applied in many various areas for strain and temperature measurement. However, according to the researchers, they’ve never been applied for larger cables with high current densities as they have. This cable is able to handle the intense electrical and electromagnetic stresses of severe environmental conditions.

The research team designed new ultra-long fiber Bragg gratings. They behave as a long quasi-continuous FBG, but all the lengths can be meters long instead of millimeters. When the usual FBGs can monitor temperature locally, these new fiber Bragg gratings can simultaneously trace the temperature modifications along the whole cable. This fiber optic technology enables fast detection of temperature changes regardless of the heat source location. It means that the accurate location can’t be defined but the utmost importance in such systems is early detection of the problem.

As a result of the real operating conditions, the fiber optic system was able to detect small temperature changes very quickly. It was even demonstrated to be more effective than the usually applied voltage taps. Moreover, the FBG sensors’ response times could be tuned and their sensitivity became higher as quench regions expanded. All these helped to find quench events faster in comparison with voltage taps even in difficult cases.

The research team offered the fiber optic system providing the technological effectiveness and minimal technological risk of the approach. And scientists are sure that they can make a contribution to other industries where superconducting magnets are really important with the help of fiber optic technology.

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Fiber Optic Technology in humans movement tracking

A team of researchers from the US university applied fiber optic technology to demonstrate the changes in city traffic because of the lockdown. Scientists had tapped into an underground telecommunication fiber optic cable and made a scientific monitoring device. Thanks to this fiber optic system, they could watch how Covid-19 brought life to a halt.

According to researchers, they shined a laser through the fiber optics and could locate vibrations from cars and pedestrians above. The fiber optic cable could detect the movement through the unique seismic signals from them. That allowed scientists to create a detailed picture of how a community ground to a halt, and then slowly came back to life when the lockdown eased.

This experiment with the fiber optic cable showed that the pedestrian traffic almost disappeared in April and stayed almost the same in June. However, the car traffic started increasing after initially declining. As a result, the vehicle traffic is actually back to normal, while people walking is still minimal. Moreover, scientists could distinguish the vibration signals from fiber optic cable from construction vehicles. In April there was no industrial activity as the construction halted. But in June the construction vehicles’ movement had started again.

Fiber optic cables trap light pulses and transport them to vast distances as signals. And when a car or person passes, the vibrations introduce a disturbance, and a scattering light returns. The researchers measured vibrations at different lengths of the fiber optic cable by estimating the time it took the back-scattered light to travel. This method is well-known as distributed acoustic sensing (DAS).

Distributed acoustic sensing (DAS) can become an instrument for tracking people’s movement instead of cell phone location data studying. Researchers can apply fiber optic cables to monitor pedestrians and cars. However, DAS can’t help in identifying a particular car or person. It can only identify a type of vehicle, for example, truck or bike.

In comparison with usual seismometers, such fiber optic cable is cost-effective and doesn’t need a source of power. There is a need for just an FBG interrogator that gets the information.

Engineers have already produced DAS systems to detect soil deformation, biologists use offshore fiber optic cables to listen in on whales, and scientists made measurements of earthquakes and water temperature in the Arctic with the help of FBG sensors. Every day fiber optic technology gets a new application.

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Fiber Optic Technology and its recent advances

During the last 60 years, fiber optic technology has been applied to improve the efficiency of developed systems in various spheres like medicine, vehicles, and other industries. Modern fiber optic solutions expand the abilities by implementing levels of data and sensing technology in the energy, medical field, and even aerospace. There are various fiber optic solutions that help researchers improve their development and make new discoveries in science.

Intrinsic and extrinsic fiber optic sensors are two wide categories of fiber optic sensors. Extrinsic fiber optic sensors utilize the fiber to manage the light to a sensing region. Then the optical signal is modulated in another environment. Talking about the intrinsic fiber optic sensors, the light remains within the waveguide. So it measures the influence of the optical fiber signal.

Intrinsic fiber optic sensor technology, where the fiber optic sensor is the fiber optic cable itself, has improved significantly during recent years. There are two main technologies connected to intrinsic fiber optic sensors: scattering and FBG. FBG methods can be fully distributed or have many sensing points. With the help of FBG sensors, scientists can define the changes by getting precise measurements. Scattering techniques depend on natural imperfections occurring in the fiber optic cable. The FBGs have a high signal-to-noise ratio in comparison with scattering techniques.

Both scattering and FBGs use different demodulation techniques. Scattering techniques get the information by observing changes in naturally back-scattering patterns. For FBG based technology, wavelength division multiplexing is the most prevalent demodulation technique. However, in certain circumstances, optical frequency domain reflectometry can become the most useful method.

Wavelength division multiplexing is able to spread to large distances and get the data rapidly. This technology can also support multiple fiber Bragg gratings on a fiber. It observes critical points more than the whole field of the data. That is why it is mostly applied in automobile crash testing as a monitoring instrument.

The scattering techniques can cover long distances and give a distributed profile of the data. They obtain information all over the entire fiber optic cable. Many systems on the market measure temperature or acoustics and are called Distributed Temperature Sensing (DTS) or Distributed Acoustic Sensing (DAS). These techniques are usually applied in monitoring a pipeline for tampering, for example, where there is no need for high-speed acquisition.

Optical frequency domain reflectometry is another demodulation technique that is mostly applied with FBG sensors where fiber Bragg gratings are placed really close and create a fully distributed sensing fiber. It has many advantages like the combination of high spatial resolution, a bunch of fiber optic sensors, a quick refresh rate, and a full distribution set. Apart from distributed sensing of a strain and temperature, this technology allows defining 2D deflection, liquid level, magnetic fields, etc.

Nowadays, thanks to fiber optic technology, scientists have an opportunity to solve any problems in their designs by using fiber optic systems. And there are still many possibilities for fiber optic technology in the future.

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Fiber Bragg Gratings (FBG) sensors’ applications

The sensing technology market has a rapid growth in the last few decades. Most of all, this is explained by the main advantages like small size, environmental and electrical immunity, and distribution capabilities. The new units of FBG sensors and fiber optic cables are valuable instruments for monitoring industrial processes and infrastructure. That’s why fiber Bragg grating (FBG) sensors are applied in many different spheres.

Fiber Bragg grating (FBG) sensors are becoming more popular each year because fiber optic applications are spreading in different aspects of life and science. Some of them are security, transportation, civil engineering, medical, and etc.

Despite the diverse application space, the market driver for fiber Bragg grating sensors has been monitoring smart structures like bridges, dams, and pipelines. FBG sensors also have had an impact on the aerospace industry by controlling the temperature, vibration, strain, and other data in real-time.

There are a lot of fiber optic applications in the oil and gas industry. Fiber Bragg grating technology, fiber optic monitoring systems, and distributed temperature sensing are commonly applied for in-well temperature monitoring and exploration activities. Distributed fiber optic sensors are also widespread in the wind power industry. They are used for the measurement of stress and strain in turbine blades.

In medicine, the ability to perform all the fiber optic solutions’ benefits is very useful for operations and certain medical procedures. Fibers can be inserted in hypodermic needles or catheters. That allows for more precise positioning of the fiber optic sensors. Moreover, fiber Bragg grating sensors are applied for temperature profiling near patients’ internal organs. And finally, FBG sensors are produced for endoscopic/colonoscopic pressure profiling.

Fiber optic technology has an impact on chemical and biochemical sensing. There are bioassays based on fiber Bragg gratings as the sensing element for protein or DNA interactions.

Nowadays, because of the development of fiber optic solutions, new fiber Bragg gratings were created. They are able to cope with high temperatures and harsh environments. It is highly useful and even crucial in power plants and for combustion and jet engines.

Today FBG sensors are becoming irreplaceable tools in different fields because of their simplicity in comparison with other technologies and advantages that they provide. And according to the tendency, fiber Bragg grating sensors will continue to apply in many existing and emerging applications.

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Fiber optic sensing solutions for extreme conditions

Electrical sensing systems (strain sensors, string-based, potentiometric, etc.) have been the main method of measuring physical and mechanical phenomena for decades. Despite their widespread application, electric sensing systems have a number of disadvantages, such as loss of signal transmission, susceptibility to electromagnetic interference, the need to organize an intrinsically safe electrical circuit (if there is a danger of explosion).

These inherent limitations make electrical sensors unsuitable or difficult to use for a number of tasks. The application of fiber optic sensing solutions is an excellent way to overcome these problems. The signal in fiber optic sensors is light in the optical fiber used instead of electricity in the copper wire of standard electrical sensors.

Over the past twenty years, a huge number of innovations in optoelectronics and in the field of fiber optic telecommunications have led to a significant reduction in the price of fiber sensor components and to a significant improvement in the quality of fiber optic systems. These improvements allow fiber optic sensors to move from the category of experimental laboratory devices to the category of widely used devices in such areas as monitoring of buildings and structures, etc.

The most widespread type of sensors

One of the most commonly used fiber optic sensors is considered to be fiber Bragg grating sensors (FBG). The fiber Bragg gratings in these sensors reflect a light signal whose spectral characteristic (wavelength) shifts along with changes in the measured parameter (temperature and/or deformation). During the manufacture of gratings, a region with a periodic change in the refractive index is created inside the optical fiber core, herewith, this region is directly called the FBG.

Optical fibers and fiber sensors are non-conductive, electrically passive, and immune to EM interference. The interrogation using a tunable high-power laser allows measurements to be made over long distances with virtually no signal loss. Additionally, in contrast to the electrical sensing system, each optical fiber channel can interrogate a variety of FBG sensors, which significantly reduces the size and complexity of such a fiber optic system.

Applications of fiber sensors

Fiber optic sensing solutions are ideal for applications where conventional electrical sensors (strain gauges, strings, thermoresistors, etc.) have proved difficult to use due to extreme conditions (long distances, EM fields, explosion protection, etc.). Since the installation and operation of fiber sensors are similar to conventional electrical sensors, it is easy to switch to fiber optic solutions. Understanding how such fiber optic systems work and the benefits of using them can greatly facilitate various measurement tasks (for example, structural health monitoring).

Benefits of FBG type

In short, the main advantages of FBG sensors include:

high sensitivity and performance;
relatively large range of measured deformations;
the best weight and overall dimensions, small size;
high noise immunity, insensitivity to electromagnetic interference, such as microwave field, spark discharge, magnetic fields, electromagnetic pulses of various nature and any intensity;
absolute electrical safety due to the absence of electrical circuits between the fiber optic sensor and the recording module;
full electrical, explosion and fire safety, high chemical resistance of sensor elements.

Extreme environmental conditions

The conditions of the environment and controlled conditions in which one or more external factors — radiation, temperature, electromagnetic field, aggressiveness, humidity, pressure, and deformation — have the maximum possible constant values are regarded as extreme.

In such conditions, primary converters of control systems for dangerous technological processes (oil production, transportation, and processing of oil and gas, nuclear power generation, storage of radioactive waste), monitoring and diagnostics systems for complex construction and engineering structures (dams, bridges, mines, etc.), and military and emergency management systems operate.

Currently, fiber optic technologies are widely used in various fields of science and technology. One of the main applications of fiber optics is the creation of portable high-sensitivity sensors. Pressure, strain, vibration, tilt, linear motion, and temperature sensors are widely applied in the industries of structural health monitoring pipelines, heating lines, power cables, mines, etc.

Application in radioactive conditions

Compared to fiber sensors, the lack of power supply at the location of electrical sensing systems does not prevent continuous remote monitoring of dangerous objects, such as nuclear power plants, in an emergency beyond design situations. For instance, the well-known events at the Japanese nuclear power plant “Fukushima-1” in 2011 were characterized by the fact that during the two weeks when the nuclear power plant was completely de-energized, there was no information from electronic sensors, which was extremely important for monitoring the technical condition of the emergency station.

Application in extreme temperatures

Problems of standard sensing systems control of tightness of tanks with liquid hydrogen, which is the fuel of modern rocket engines, has a temperature of -253 °C and very high fluidity, due to the fact that at such temperatures, most materials become very fragile, and the sensitivity of palladium sensors quickly decreases.

It is problematic to measure the pressure and dryness of superheated steam in gas generators and superheated gas in jet engine nozzles at temperatures up to + 600 °C since piezoelectric sensors quickly degrade at temperatures above + 300 °C. Modern FBG sensors of physical quantities are heat-resistant (up to +2300 °C) and cold-resistant (up to -270 °C). This provides reliable and long-term monitoring of the technical condition of high-temperature and cryogenic objects.

Operation during electromagnetic interference

Measurements of physical quantities using electrical sensing systems in conditions of high-power electromagnetic interference, including guidance on coaxial electrical cables and sensors from lightning discharges, in conditions of monitoring the patient’s pulse in a medical nuclear magnetic resonance facility, as well as measurements of high voltages and high currents in electrical engineering, are highly problematic.

Fiber Bragg grating sensors are completely immune to electromagnetic interference and are stable insulators. This makes it possible to measure high voltages up to 800 kV and high currents up to 200 kA with high accuracy (class 02s) by fiber optic sensing technology.

Application in an aggressive environment

Measurements of physical quantities of chemically aggressive media, long — term measurements of deformation of dynamically loaded objects and structures, as well as multi-sensor measurements-with the number of control points in several hundred and thousands, are also problematic for electrical sensing systems since the volume of measuring electrical cables is unacceptably increasing.

Distributed fiber optic sensors are multi-sensors: up to 10 thousand consecutive intra-fiber sensors can be used in one optical fiber (fiber optic cable) to measure physical quantities (temperature, strain, seismoacoustics, pressure, radiation, etc.). Multimode fiber optic cables allow performing remote measurements with high accuracy using borehole video cameras, and temperature fields — using pyrometers and thermal imagers.

Advantages of metrological calibration

A serious problem of electrical sensing systems embedded in objects (in the concrete of hydraulic dams and bridges, in the pylons and walls of high-rise buildings, etc.) presents the practical difficulty of their periodic calibration (metrological verification).

Modern fiber sensors have the function of metrological self-monitoring (FMSM) due to the multimodality of the optical signal, which allows for self-calibration of fiber optic sensors in real-time without stopping the controlled processes and without verification standards.

Today’s situation

In the last decade, there were implemented many similar applications of modern fiber sensors and systems in extreme environments of nuclear, oil and gas, and aerospace industries, shipbuilding, hydraulic engineering, energy, construction, military, and natural emergencies.

Moreover, the durability of FBG sensors in these extreme conditions creates an obvious advantage of their use in the energy, oil and gas, aerospace, construction, and transport industries in comparison with non-optical types of measuring systems.

Thus, the extreme operating conditions of fiber Bragg grating sensors, for example in wells (extreme parameters, flammable, aggressive and abrasive environments) or power plants (ultra-high currents and discharges, voltages and fields, significant ionizing radiation), actually belong to the usual operating conditions of fiber optic sensors.

How to find the best fiber optic solution?

If you are looking for reliable fiber optic sensing solutions for structural health monitoring, you should choose the Optromix company. Optromix is a fast-growing vendor of fiber Bragg grating (FBG) product line such as fiber Bragg grating sensors, FBG interrogators and multiplexers, Distributed Acoustic Sensing (DAS) systems, Distributed Temperature Sensing (DTS) systems. The company creates and supplies a broad variety of fiber optic solutions for monitoring worldwide. If you are interested in structural health monitoring systems and want to learn more, please contact us at info@optromix.com

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