Dust explosions are often catastrophic, causing irreversible damage and sadly, human fatalities. When an ignition source, such as electrical or thermal equipment, enters a space where there is a high concentration of dust in the air, typically in a confined building or vessel, extreme heat increases pressure in the space and causes an explosion. In such an environment you’d likely notice very low visibility, much like being in a dense fog. But these situations are not uncommon. In fact, records show that almost every industry has fallen victim to dust explosions – a series of devastating incidents throughout history, even in recent years.
Most industries which store, handle and process materials and substances, produce dust.
Firstly, there are a great number of substances in food processing that produce dusty environments. Sugar and flour processing are huge industries, but also grains, or anything that usually comes in a powdered form, such as instant coffee, custard and soup to name a few.
It is not just food that is processed on an enormous scale. Processing plants for wood and chemicals often involve handling great volumes of powder, which undergo or become a by-product of the multiple stages in the process, whether it’s coating, cutting, mixing or just transporting from one point to another. Recycling facilities similarly, handle large volumes of plastic and paper powder.
The agricultural industry relies on numerous processes and environments daily, many of which also contain potentially hazardous dust volumes. This includes processing sites, like fertilizer plants and industrial composting, and vast storage facilities like grain elevators and silos.
In coal mines, processing methods generate coal dust much like in processing plants. When the rock is crushed it disperses dust into the surroundings, and when transported, the rock often gets knocked and damaged, throwing more dust into the air. What’s more, coal mining releases methane gas which collects in coal rock over millennia. Methane gas is highly flammable and is equally prone to explosion.
How can Cygnus 1 Ex help?
There are many ignition sources that may be brought into these areas for various reasons. One of these reasons performs a rather crucial task – ultrasonic testing equipment designed to carry out essential maintenance checks on the machinery operating to these processes. Whilst maintenance is also vital to the safety of these areas, and may even contribute to prevention of dust clouds by preventing leakage, the maintenance equipment itself needs to be safe to handle in these hazardous environments.
The Cygnus 1 Ex is certified safe to use in locations where there is a risk of fire or explosion due to the presence of ignitable or flammable substances in the air at concentrations high enough to produce an ignitable mixture. This includes gases, vapours, and in this case, dust.
This is because Cygnus 1 Ex is Intrinsically Safe. For any equipment like Cygnus 1 Ex, that contains electronic components including batteries, intrinsic safety technology limits the energy present in a system, meaning no arc or spark can be generated, and no component can heat up enough ignite a hazardous atmosphere under any conditions. This applies under both normal use and with applied fault conditions, at low power levels, and low stored energy.
Cygnus 1 Ex has an Intrinsically Safe Design, featuring:
- Limited output energy to prevent ignition of explosive atmospheres.
- Anti-static enclosure to prevent static electricity discharge.
- Multiple redundant safety components.
- In the event of damage or a fault, no high surface temperatures are generated that could ignite an explosive atmosphere.
‘Intrinsically Safe’ is an Ex Protection Concept, used to determine which areas of a facility (‘zones’) the equipment is suitable for. The term ‘Ex’ is recognized globally when referring to explosive atmospheres and the schemes used to prevent explosions. In both IECEx, ATEX and North American systems, intrinsically safe equipment can be used in any Zone or Division with the correct equipment protection level.
When it comes to dust, Cygnus 1 Ex is certified to Zones 21 and 22. Zone 21 identifies areas where combustible dust is occasionally present. Zone 22 identifies areas where combustible dust is not usually present but could be for short periods.
More first-class Cygnus 1 Ex features
The Cygnus 1 Ex ultrasonic thickness gauge offers an invaluable leap forward for safe structural inspection in hazardous areas. Reviewed as “versatile, multifunctional, robust and intuitive,” by our customers, this intrinsically-safe gauge provides first-class user control and flexibility, eliminating the need for plant shutdown or a Hot Work permit. Equipped with 3 measuring modes and a selection of probes, the gauge is capable of measuring a range of materials and metals with severe corrosion or protective coatings up to 20mm thick. This saves considerable time and money removing coatings!
The great news for advanced users is, the Manual Measurement Mode ensures measurement on trickier areas like heavy corrosion, is easier and more accurate thanks to more versatile settings. Like a flaw detector, you can manually adjust two gates, positioning them anywhere on the A-scan, alter gate height, start-point and width, and measure from a gate or between gates. Furthermore, Time-Controlled Gain (TCG) enables introduction of different gains to boost weaker echoes.
When storing and analysing data, you’ll enjoy equal flexibility. Comprehensive data logging offers linear, templates, and 2-D or 3-D grid formats, with 16 grid patterns and annotation capability. Radial Points enable further investigation on areas of interest or heavy corrosion, allowing you to add up to 12 additional measurements ‘around’ the principal measurement.
To learn more, please visit cygnus-instruments.com/product/cygnus-1-ex/.
