OperationThe Model 770-55-U is a pilot controlled valve equipped with an adjustable, 2-Way flow pilot, an orifice assembly, and asolenoid pilot.The needle valve [1] continuously allows flow from valve inlet into the upper control chamber [2]. The pilot [3] senses the differentialpressure across the orifice plate [4], and together with the solenoid [5], controls outflow from the upper control chamber.Should orifice differential pressure rise above pilot setting, the pilot throttles, enabling pressure to accumulate in the uppercontrol chamber, causing the main valve to throttle closed, thereby limiting flow to the pilot setting.Should orifice differential pressure fall below pilot setting, the pilot releases accumulated pressure causing the main valve tomodulate open.Should the solenoid close, pressure in the upper control chamber accumulates causing the main valve to shut off. NormallyClosed, Normally Open and Last Position models are available.The needle valve controls the closing speed. The downstream cock valve [6] enables manual closing.
đang được dịch, vui lòng đợi..
