ASCO Joucomatic’s new 551 series of stainless steel (316L) valves has been developed for use in corrosive and hazardous environments in the petrochemical, process, chemical, oil and gas and food industries. ATEX approved for all categories including 1GD (zones 0/20) and/or SIL level 4, the marine grade (316L) stainless steel valves are particularly suited to piloting process actuators in hazardous areas, both on and offshore. The 551 valves employ internal parts of 316L or 304L stainless steel and seals of silicone and polyurethane. This combination enables the valves to be used on filtered air and neutral gases at pressures up to 10bar, and across a wide ambient temperature range from -40C to +60C. The 551 series are 1/4” valves which are available in both NAMUR interface and body ported (BSP and NPT) versions. They are offered as of 3/2 or 5/2 configurations, with either mono-stable (solenoid/spring) or bi-stable (solenoid/solenoid) operators. In both cases, the solenoids have the option of being equipped with manual (impulse-type) overrides.