ASCO（Emerson）

ASCO, founded in 1888 in the United States and now part of Emerson's fluid control and pneumatics business, is the world's best-known manufacturer of solenoid valves — the compact electrically operated valves that switch air, water, gas, steam and refrigerants in virtually every automated system. The catalog spans two-way, three-way and four-way pilot valves in brass, bronze, stainless steel and exotic alloys, with NAMUR-mounted versions designed to sit directly on pneumatic valve actuators, hazardous-location and explosion-proof coils for refinery service, and the RedHat coil platform familiar to generations of maintenance engineers. ASCO also absorbed the Numatics brand of air preparation and pneumatic components, extending the range into filters, regulators and cylinders. In valve automation, ASCO solenoids are the de facto standard pilot valve on quarter-turn spring-return packages: their reliability and coil options determine the fail-safe behavior of the entire assembly. With global manufacturing and documentation in dozens of languages, ASCO remains the first brand most engineers consult when specifying solenoid control for actuators, process media switching and safety shutdown circuits.