Instead of switching back and forth like two position valves, selectors (multiposition valves) step incrementally through continuous revolutions (bi-directionally with the microelectric and universal actuators). The preload design allows the rotor to be inspected or replaced without taking the valve off the actuator, and valves ordered with a microelectric actuator are permanently aligned.
INJECTORS, SELECTORS, AND VALVES (Which one do I need?) ACTUATORS FITTINGS PRODUCTS FOR GC LIQUID HANDLING ADDITIONAL PRODUCTS UHPLC / NANO LC
PRODUCT SUPPORT VALVE APPLICATIONS CHROMATOGRAMS GENERAL REFERENCE UNIT CONVERSION REGULATORY SUPPORT