A brief history of gas detection 

The evolution of gas detection has changed considerably over the years. New, innovative ideas from canaries to portable monitoring equipment provides workers with continuous precise gas monitoring. 

The Industrial Revolution was the catalyst in the development in gas detection due to the use of fuel that showed great promise, such as coal. As coal can be extracted from the earth through either mining or underground mining, tools like helmets and flame lights were their only protection from the dangers of methane exposure underground that were yet to be discovered. Methane gas is colourless and odourless, making it hard to know it’s presence until a noticeable pattern of health problems was discovered. The risks of gas exposure resulted in experimenting with detection methods to preserve the safety of the workers for years to come. 

A Need for Gas Detection 

Once gas exposure became apparent, miners understood that they needed to know whether the mine had any pocket of methane gas where they were working. In the early 19th century, the first gas detector was recorded with many miners wearing flame lights on their helmets to be able to see while they were working, so being able to detect the extremely flammable methane was paramount. The worker would wear a thick, wet blanket over their bodies while carrying a long wick with the end lit on fire. Entering the mines, the individual would move the flame around and along the walls looking for gas pockets. If found, a reaction would ignite and be noted to the crew while the person detecting was protected from the blanket. With time, more advanced methods of detecting gas were developed. 

The Introduction of Canaries 

Gas detection moved from humans to canaries due to their loud chirps and similar nervous systems for controlling breathing patterns. The canaries were placed in certain areas of the mine, from there, workers would check on the canaries to care for them as well as see if their health had been affected. During the work shifts, miners would listen to the canaries chirp. If a canaries began to shake its cage, that was a strong indicator of a gas pocket exposure in which it has started to affect its health. Miners would then evacuate the mine and noted that it was unsafe to enter. On some occasions if the canary stopped chirping all together, miners knew to make a swifter exit before the gas exposure had a chance to affect their health. 

The Flame Light 

The flame light was the next evolution for gas detection in the mine, as a result of worries about animal safety. Whilst providing light for the miners, the flame was housed in a flame-arrestor shell which absorbed any heat and captured the flame to prevent it from igniting any methane that may be present. The outside shell contained a glass piece with three incisions running horizontally. The middle line was set as the ideal gas environment while the bottom line indicated an oxygen-deficient environment, and the top line indicated methane exposure or an oxygen-enriched environment. Miners would light the flame in an environment with fresh air. If the flame lowered or started to die, it would indicate that the atmosphere had a low oxygen concentration. If the flame grew larger, the miners knew that methane was present with oxygen, both cases indicating that they needed to leave the mine. 

The Catalytic Sensor 

Although the flame light was a development in gas detection technology, it however, was not a ‘one size fits all’ approach for all industries. Therefore, the catalytic sensor was the first gas detector that has a resemblance to modern technology. The sensors work on the principle that when a gas oxidises, it produces heat. The catalytic sensor works through temperature change, which is proportional to the concentration of gas. Whilst this was a step forward in the development of the technology required for gas detection, it still initially required manual operation in order to receive a reading. 

Modern Day Technology 

Gas detection technology has been developed tremendously since the early 19th century in which the first gas detector was recorded. With now over five different types of sensors commonly used across all industries, including Electrochemical, Catalytic Beads (Pellistor), Photoionisation detector (PID) and Infrared Technology (IR), along with the most modern sensors Molecular Property Spectrometer™ (MPS) and Long-Life Oxygen (LLO2), modern day gas detectors are highly sensitive, accurate but most importantly reliable, all of which allow for all personnel to stay safe reducing the number of workplace fatalities. 

What is a Flame Detector and How Does it Work?

What is a Flame Detector? 

A flame detector is a type of sensor that can detect and respond to the presence of a flame. These detectors have the ability to identify smokeless liquid and smoke that can create open fire. For example, in boiler furnaces flame detectors are widely used, as a flame detector can detect heat, smoke, and fire. These devices can also detect fire according to the air temperature and air movement. The flame detectors use Ultraviolet (UV) or Infra-Red (IR) technology to identify flames meaning they can alert to flames in less than a second. The flame detector would respond to the detection of a flame according to its installation, it could for example sound an alarm, deactivate the fuel line, or even activate a fire suppression system. 

Where would you find these Detectors? 

  • Industrial warehouses
  • Chemical production plants 
  • Chemical stores 
  • Petrol storage and pump stations 
  • Arc welding workshops 
  • Power plants 
  • Transformer stations 
  • Underground tunnels 
  • Motor testbeds 
  • Wood stores 

What are the Components of a Flame Monitoring System and does it work?

The major component of a flame detector system is the detector itself. It comprises of photoelectric detective circuits, signal conditioning circuits, microprocessor systems, I/O circuits, and wind cooling systems. The sensors in the flame detector will detect the radiation that is sent by the flame, the photoelectric converts the radiant intensity signal of the flame to a relevant voltage signal and this signal would be processed in a single chip microcomputer and converted into a desired output. 

How many types of Flame Detectors are there and how do they work? 

There are 3 different types of flame detector: Ultra-Violet, Infra-Red and a combination of them both Ultra-Violet-Infra-Red 

Ultra-Violet (UV) 

This type of flame detector works by detecting the UV radiation at the point of ignition. Almost entirely all fires emit UV radiations, so in case of the flame, the sensor would become aware of it and produce a series of the pulses that are converted by detector electronics into an alarm output.  

There are advantages and disadvantages of a UV detector. Advantages of UV detector include High-speed response, the ability to respond to hydrocarbon, hydrogen, and metal fires. On the other hand, the disadvantages of UV detectors include responding to welding at long range, and they may also respond to lightning, sparks, etc. 

Infra-Red (IR) 

The infra-red flame detector works by checking the infrared spectral band for certain ornamentation that hot gases release. However, this type of device requires a flickering motion of the flame. The IR radiation may not only be emitted by flames, but may also be radiated from ovens, lamps, etc. Therefore, there is a higher risk for a false alarm 

UV-IR 

This type of detector is capable to detect both the UV and IR radiations, so it possesses both the UV and IR sensor. The two sensors individually operate the same as those described, but supplementary both circuitry processes signals are present due to there being both sensors. Consequently, the combined detector has better false alarm rejection capability than the individual UV or IR detector. 

Although there are advantages and disadvantages of UV/IR flame detector. Advantages include High-speed response and are immune to the false alarm. On the other hand, the disadvantages of UV/IR flame detector include the issue that it cannot be used for non-carbon fires as well as only being able to detect fires that emits both the UV/IR radiation not individually.  

Are any products available? 

The FGard IR3 delivers superior performance in the detection of hydrocarbon fires. The device utilises the latest IR flame detection algorithms to ensure maximum false alarm immunity. The detector has been independently tested to demonstrate it can detect a hydrocarbon fuel pan fire at nearly 200 feet in less than 5 seconds. The FGuard IR3 has a multi spectrum IR allowing for 60 metre flame detection range. That can detect all Hydrocarbon fires with no condensation forming on the window, improving reliability and performance across temperature. This product has fast detection time responding in less than 5 seconds to 0.1m² fire at 60 metres.  

Crowcon offers a range of infra-red (IR) and ultra-violet (UV) based flame detectors for quickly detecting flames at a distance. Depending on model, this includes a variety of gas and fuel fires including those generated from hydrocarbons, hydrogen, metals, inorganic and hydroxyl sources.

Are Silicone Implants Degrading your Gas Detection?

In gas detection terms, pellistors have been the primary technology for detecting flammable gases since the 60s.  In most circumstances, with correct maintenance, pellistors are a reliable, cost-effective means of monitoring for combustible levels of flammable gases.  However, there circumstances under which this technology may not be the best choice, and infrared (IR) technology should be considered instead.

Continue reading “Are Silicone Implants Degrading your Gas Detection?”