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Gas Detectors – Gas Analyzers


Gas Detectors

Gas detection systems are very crucial when the customer has to deal with dangerous gases. Gas detection instruments for oxygen, flammable and toxic gas can be supplied by our company providing safety in the detection point. The most vital product categories are the following: Fixed gas detection systems which are installing in a fixed point and protect the plant and Portable gas monitors which mainly are small in size and are protecting people.

Fixed gas detection systems

Crowcon use a variety of measurement, protection and communications technologies to offer a flexible range of products able to measure flammable, toxic and oxygen gases, report their presence and activate alarms or associated equipment.

Utilising the experience gained since their formation in 1970, Crowcon fixed detectors have been proven in many arduous environments, including oil and gas exploration, water treatment, chemical plants and steel mills. They are however also chosen in many other applications where reliability, dependability and lack of false alarms are valued, for example in the automotive and aerospace manufacturing sectors, on scientific and research facilities and in high-utilisation medical, civil or commercial plants.

Series X-Gard is the most usable series detecting almost the most various gases. Cooperating with gas panels such as Gasflag, Gasmaster, Vortex or Gasmonitor can cover from a small laboratory or a storeroom up to a big factory.

Product range overview

F-Gas Detector – A high quality infrared fixed-point detector that delivers dependable detection of freon gases

Xgard A comprehensive range of SIL-rated, intrinsically safe (I.S.) or flameproof (Ex d) fixed point gas detectors, available in aluminium, stainless steel or GRN polymer housings.

Xsafe Features a tough alloy housing and the same standard of design and reliability as Crowcon hazardous area detectors but without the extra cost of certified electronics.

IREX A fast response infra-red flammable gas detector with mV output designed to allow it easy upgrading of existing pellistor based fixed point gas detectors.

IRmax An advanced, low power, SIL 2 infra-red flammable gas detector with multiple output and display options particularly suited to hydrocarbon and chemical installations.

TXgard-IS+ An intrinsically safe (I.S.) toxic or oxygen gas detector with local display and a 4-20mA output, suitable for a wide range of gases.

TXgard Plus A flameproof (Ex d) toxic or oxygen gas detector with local display and a 4-20mA output, suitable for a wide range of gases.

Flamgard Plus A flameproof (Ex d) pellistor based flammable gas detector with local display and a 4-20mA output, suitable for gases including hydrocarbons, hydrogen and petrol vapours.

TCgard Thermal conductivity based, 4-20mA output, Ex d gas detector for detecting % volume levels of gases such as argon, carbon dioxide, methane or hydrogen in binary mixtures.

Open Path IR Detectors Based around a transmitter and a receiver detecting gas within the line of sight between them, these detectors can be used to cover a wider distance (up to 140m) than point detectors.

Flame detectors Complementing Crowcon’s gas detection products is a range of IR and UV based flame detectors capable of detecting hydrocarbon, hydrogen, metal, inorganic and hydroxyl fires

Gas monitors range overview

Gasflag A single 4-20mA input panel with bright alarm LEDs, sounder and relay for switching external devices. Ideal for boiler rooms, LPG vehicle filling stations and swimming pools.

CellarSafe An easy-to-use combined sensor and control system for CO2 & O2 monitoring designed specifically for applications such as cellars, breweries, wineries and hospitality outlets.

Gasmaster Extensively featured 1-4 channel SIL 2 validated control panel with 4-20mA or modbus outputs, large multi-lingual LCD display and alarm / fault relays.

Vortex Wall mount, rack or Ex d flameproof control panel for 1-12 gas detectors with battery back-up, internal alarm, relays and RS-485 Modbus communications.

Gasmonitor 19” rack based modular control system for up to 16 gas detectors or 32 fire zones. Features multiple outputs, alarms and relays, plus voting software functionality.

Hydra32 and 256 Well suited to car park monitoring, Hydra has relays for fan control and can monitor up to 32 or 256 points for carbon monoxide, nitrogen dioxide, petrol vapour or LPG.

Portable Gas detection

Crowcon provide both single gas and multigas monitors for personal monitoring and portable safety applications providing protection against a wide range of industrial gas hazards. Models vary by size and complexity depending on the number and type of gas sensors used, display and certification but it is Crowcon’s philosophy that each should be properly suited to its task.

Small in size instruments easy to carry with you for one up to four gases such as Crowcon Clip, Gasman, T3 or triple plus can protect the personnel from any dangerous gas leakage.

Product range overview

Gas-Pro IR Confined space entry monitor that detects potentially explosive gases using IR sensor technology.

Gas-Pro PID Confined space entry monitor that utilises the Photo Ionization Detection technology that allows users to detect hundreds of Volatile Organic Compounds (VOC’s).

Crowcon Clip Easy to use, event logging single gas detector with display for H2S, CO or O2. Well matched to users looking for a simple unit but who want a display and event / alarm logging.

Gasman Single gas full function detector available for a very wide range of gases. Detailed logging and high gas flexibility mean Gasman is well suited as either an upgrade from disposable units or as a supplementary unit for exotic gases, for example on chemical plants. The CO2 version is ideally matched to the requirements of the hospitality and beverage industry while a specially filtered CO version is a perfect fit with steel plant needs.

Tetra:3 Compact multigas detector with top display. Offering the “standard four” gases of H2S, CO, O2 and flammables, but also SO2, O3 and NH3 as frequently required in the water industry and CO2 (safe area) for use in brewing and beverage sectors. Also available with special filters and sensors for use in the steel industry.

Gas-Pro Confined space monitor with internal pump option and class leading size. Offering up to 5 gases from a range specifically matched to the hazards found in confined spaces, particularly in the water, construction, manufacturing and hydrocarbon industries.

Tetra Multigas personal monitor with internal pump option. Popular with utility companies and those looking for pumped units capable of detecting more exotic gases, such as those in the chemical or water treatment industries.

TriplePlus+ Iconic, superior grade multigas detector with IR sensor and internal pump options. Field proven across many oil and gas installations and in applications where IR detection of hydrocarbons is key, eg purging of tanks.

Detective+ Temporary area monitor with compelling audible and visual alarms. Linkable for virtual fencelines and often deployed during turnarounds or construction work. Now available with a wireless module for interconnecting cables.

LaserMethane mini Hazardous area approved, low level (ppm) methane detector suitable for use up to 100m from source of leak. Highly flexible in use, applications range from leak surveys on gas processing plants to localising emission sources in hard to reach places eg on landfill sites, locked premises or difficult to access pipes and ducts.


Gas Analyzers

Common Questions-Information

What is Accuracy?
The “accuracy” of a measurement refers to how close a measurement is to a “true” (actual) value. The accuracy of most instrumentation, is dependant on the accuracy of the device, or method used for calibration. Therefore, most process instruments cannot be quoted for accuracy as they may only be as “accurate” as their calibration. What is normally meant in this case is “reproducible” or “precise”.

What is Precision?
Precision is a measure of the spread of different readings. Precision and accuracy are unrelated to each other, meaning that you can be very PRECISE but not ACCURATE. In practical terms precision is often more relevant to an online analyzer than accuracy. Precision is also as a synonym for the resolution of the measurement e.g. a measurement
that can distinguish the difference between, 0.01 and 0.02 is more precise (has a greater resolution) than one that can only tell the difference between 0.1 and 0.2 even though they may be equally accurate.

What is Resolution?
Resolution refers to the smallest change that a sensor can detect in the quantity it is measuring. Resolution of an online instrument can be affected by the sensor itself, the manner of digitization and the capability of the display. In the past the resolution was limited by the display (a small analogue gauge), so ‘resolutions’ were often reported as the ability to read a gauge. The development of digital displays, means that the display is no longer the limiting factor, but is often still used to define the resolution. Quoting a resolution which is better than the precision is quite misleading. For example quoting to a resolution of the display of an online O2 meter at 0.001 is misleading if the sensor precision is > 0.01.

What is flammable risk?
In order for gas to ignite there must be an ignition source, typically a spark (or flame or hot surface) and oxygen. For ignition to take place the concentration of gas or vapour in air must be at a level such that the ‘fuel’ and oxygen can react chemically. The power of the explosion depends on the ‘fuel’ and its concentration in the atmosphere. The relationship between fuel/air/ignition is illustrated in the ‘fire triangle’.

The ‘fire tetrahedron’ concept has been introduced more recently to illustrate the risk of fires being sustained due to chemical reaction. With most types of fire the original fire triangle model works well – removing one element of the triangle (fuel, oxygen or ignition source) will prevent a fire occurring. However, when the fire involves burning metals like lithium or magnesium, using water to extinguish the fire could result in it getting hotter or even exploding. This is because such metals can react with water in an exothermic reaction to produce flammable hydrogen gas.

Not all concentrations of flammable gas or vapour in air will burn or explode. The Lower Explosive Limit (LEL) is the lowest concentration of ‘fuel’ in air which will burn and for most flammable gases it is less than 5% by volume. So there is a high risk of explosion even when relatively small concentrations of gas or vapour escape into the atmosphere.

LEL levels are defined in following standards: ISO10156, and IEC60079. The ‘original’ ISO standard lists LELs obtained when the gas is in a static state. LELs listed in the EN and IEC standards were obtained with a stirred gas mixture; this resulted in lower LEL’s in some cases (i.e. some gases proved to be more volatile when in motion).

What is toxic risk?
Gases and vapours produced, under many circumstances, have harmful effects on workers exposed to them by inhalation, being absorbed through the skin, or swallowed. Many toxic substances are dangerous to health in concentrations as little as 1ppm (parts per million). Given that 10,000ppm is equivalent to 1% volume of any space, it can be seen that an extremely low concentration of some toxic gases can present a hazard to health.
Gaseous toxic substances are especially dangerous because they are often invisible and/or odourless. Their physical behaviour is not always predictable: ambient temperature, pressure and ventilation patterns significantly influence the behaviour of a gas leak. Hydrogen sulphide for example is particularly hazardous; although it has a very distinctive ‘bad egg’ odour at concentrations above 0.1ppm, exposure to concentrations of 50ppm or higher will lead to paralysis of the olfactory glands rendering the sense of smell inactive. This in turn may result in the assumption that the danger has cleared. Prolonged exposure to concentrations above 50ppm will result in paralysis and death.
Definitions for maximum exposure concentrations of toxic gases vary according to country. Limits are generally time-weighted as exposure effects are cumulative: the limits stipulate the maximum exposure during a normal working day.

What is Oxygen risk?
The normal concentration of oxygen in the atmosphere is approximately 20.9% volume. In the absence of adequate ventilation the level of oxygen can be reduced surprisingly quickly by breathing and combustion processes.

Oxygen levels may also be depleted due to dilution by other gases such as carbon dioxide (also a toxic gas), nitrogen or helium, and chemical absorption by corrosion processes and similar reactions. Oxygen sensors should be used in environments where any of these potential risks exist.

When locating oxygen sensors, consideration needs to be given to the density of the diluting gas and the “breathing” zone (nose level). For example helium is lighter than air and will displace the oxygen from the ceiling downwards whereas carbon dioxide, being heavier than air, will predominately displace the oxygen below the breathing zone. Ventilation patterns must also be considered when locating sensors.

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