T20和T21型顶装式浮球液位开关.pdf

Top Mounting T20 and T21 Liquid Level Switches D E S C R I P T I O N T20 and T21 units are simple, reliable float switches, designed for top mounting into tanks or vessels. T20 units utilize a single switch mechanism and float. T21 tandem units utilize two switch mechanisms and two separate floats. T20 and T21 models are available for any type of open or closed vessel, with either threaded or flanged type mounting, and actuating depths of up to 48 inches (1219 mm). F E A T U R E S 1 • Float diameters of 3 × 5, 4 and 4⁄2 available • Tank connections available in 1 NPT, cast iron, forged, or stainless steel flanges • Choice of switch mechanism: Mercury Pneumatic Dry contact Hermetically sealed • Choice of switch enclosure: NEMA 1 carbon steel for pneumatics NEMA 4X/7/9 Class I, Div. 1, Groups C D, O P T I O N S polymer coated aluminum • NACE NEMA 4X/7/9 Class I, Div. 1, Group B, polymer coated aluminum • CENELEC approved cast iron housing • Housing heater A P P L I C A T I O N S • Float guide cage • Day tanks • Condensate receivers • Tropicalized switch mechanism • Fuel storage tanks • Cooling towers • Special flange face finishes • Flash tanks • Interface • Submersible ho