FLUIDIC VALVES FOR VARIABLE-CONFIGURATION GAS TREATMENT

he paper surveys recent development in the highly specialized field of chemical engin-eering: vehicle exhaust gas aftertreatment, where variable configuration systems are currently introduced or considered. These respond to varying operating conditions by inserting into the gas treatment flowpath different reactors. The main practical problem are the valves for gas flow switching. Usual mechanical valves are costly, failure prone, heavy (especially the solenoid variants), and not robust enough to withstand the adverse conditions of high temperature, vibration, shocks and dripping water and mud at the usual locations under vehicle body. Fluidic no-moving-part valves, inexpensive and robust, are proposed as an attractive alternative. Especially in their novel axisymmetric layout, they may be very compact, in fact integral with reactor body. The qualitative change brought by the new approaches may provide an inspiration to other areas of chemical engineering