ASCO Joucomatic’s new 2oo2D-SOV safety enclosure system is designed as a key component to provide added levels of operating safety in emergency shutdown systems (ESD) and other critical applications in water treatment, pharmaceutical and petrochemical industries – typically flaring systems on stack pipes. The 2oo2D-SOV is a factory-assembled and factory-tested enclosure, designed to ensure complete functional reliability and the reduction of spurious tripping in the most critical of process applications. The unit comprises a stainless steel or powder coated steel enclosure, housing ISO-2 solenoid valve assemblies. The valve assemblies provide the end user with either redundant control “2oo2” (two out of two) protection, or single solenoid with a Hot Back-up “1oo1” (one out of one) standby. Optimising the operation of the solenoid valves are three pressure switches, which constantly monitor the solenoid valve position and provide diagnostics information.
When configured in 2oo2D-SOV mode, the safety system functions as a redundant actuating device to control air to process valves. In this operation the “two-out-of-two” voting offers high levels of safety protection as both solenoids must be de-energised to trip the system. In redundant mode the operation of the 2oo2-SOV is optimised with a PLC, which is used to perform diagnostics and periodic on-line testing to assure high availability.
