“Using aerofoils X-Suppress uses the pressure front of an approaching explosion to atomise water into small droplets instanteously.  It requires no detection or initiation device and generates 50 _m sized water droplets within 50msec to suppress the incident flame front,” he comments. Positive advantages:
X-Suppress allows normal ventilation and is said to be an ‘ideal protection solution for ventilation shafts’.  “It can be used for point protection of people or vital components as well as complete protection of larger objects.  With many ignition sources unknown and large scale risk present in many installation X-Suppress allows comprehesive protection to avoid the spread of any conflagration,” Graeme reports.
This new development follows a programme of research from the University of Sheffield and, during demonstrations on a medium scale, has been successful in reducing overpressures arising out of gas explosions, says researchers. 
“Extensive testing has been carried out in a wind tunnel where the predictability of X-Suppress is seeking exploitation partners to build upon its significant body of work for both onshore and offshore applications,” says Graeme.
Key features of X-Suppress include:
• A mitigation device which uses water at ambient temperature and pressure;
• It avoids the use of inerts or energetic injection processes;
• The device uses the initial energy in the explosion to induce water atomisation and halt the progress of the explosion front;
• It needs low energy to activate the device;
• Water droplets continue to be generated where they are needed to suppress the incident flame front;
• Normal levels of ventilation can be maintained with the device in place
Operating principles
Water-filled aerofoils provide both the water reservoir for explosion suppression and the necessary aerodynamic profile for the generation of a fine mist at the onset of explosion.The initial phase of a gas explosion creates a flow of gas away from the point of ignition. This gas flow, interacting with the X-Suppress device, draws water from the device and simultaneously atomises this water into a fine mist. 
“Development work and testing has now been carried out using a high speed wind tunnel combined with explosion mitigation assessment at small and medium scale,” comments Graeme.
“The dynamics of water ejection and droplet creation have been characterised by high speed video and time resolved laser diffraction sizing, which have shown an effective response time of the device of around 50 msec and droplet sizes in the 50 mm range,” he confirms.
Droplet densities produced have apparently been measured in the range of 2 - 3 kg/m3 and are consistent with published values required for explosion suppression. Over 200 small scale tests have been carried out in the University of Sheffield’s 5m long, 0.3m wide explosion tube. More information? Visit: www.xsuppress.com
References
Further information on the research background to the X-Suppress system can be found at the following references
1. B C R Ewan, M Moatamedi,
‘The Study of Induced Water Flow Devices in the Suppression of Gas Explosions’, Trans. IChemE Pt. B, Vol 80, 126 - 134 (2002).
2. B C R Ewan, M Moatamedi, ‘Induced Water Atomisation Devices for Gas Explosion Suppression’, Process Safety Progress Vol 21(2), 1-6 (2002).
3. C Catlin, ‘Passive Explosion Suppression by
Blast-Induced Atomisation from Water Containers’,
J Hazardous Materials A94, 103 - 132 (2002).

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