SAFETY IN THE PLANT
New generation Ventex valves are easily integrated into a process
VALUE-ADDED VALVES
Steve Bell presents an innovative new design for explosion isolation valves
S
everal techniques and protective devices – such as explosion venting, isolation or suppression devices – are available to contain or mitigate the major effects of an explosion in an industrial process. Major effects associated with explosions include the risk of flame and pressure wave propagation throughout the installation. Te pressure waves generated by the initial explosion can cause dust in adjacent equipment or areas to become airborne again, which can trigger secondary explosions. In practice, secondary explosions are often more energetic explosions than the initial explosion in part due to compression effects in ducts and piping.
Te purpose of non-return valves such
as Ventex valves is to prevent pressure waves, generated by the initial explosion, from propagating throughout the installation thereby avoiding secondary explosions from happening. Te Ventex valve is passive, meaning that it does not require any external source of power to operate. Te energy of the initial pressure wave is sufficient to close the valve effectively blocking the pressure wave and flames and preventing any further propagation. Te valve ‘isolates’ adjacent equipment and areas from the equipment where the initial explosion event took place.
MAXIMUM EXPLOSION PRESSURE RESISTANCE Unlike conventional explosion non- return or flap valves, Ventex valves are able to withstand much higher explosion
pressures. For example, these valves can withstand a maximum pressure of 10 bar and are a good option to protect process equipment such as hoppers designed to withstand higher pressures as well; 10 bar being generally the maximum pressure allowed in a confined environment. Te most recent series of Ventex valves,
available in diameters ranging from DN100 to DN600, is now suitable for velocities up to 30m/s in the direction of the explosion, compared with 20 and 25m/s for older models. To validate the performance of the valve, numerous pre-certification tests were carried out and it was found that pressure losses are 20% lower when compared with previous models.
NEW SEAL Obviously, the seat and seal of a Ventex valve are important construction elements. Te seat and seal help to ensure proper
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