Fisher 377 pressure-sensing trip valves are for control applications where a specific valve/actuator action is required when supply pressure falls below a specific point. When supply pressure falls below the trip point (see figure 1), the trip valve causes the actuator to fail up, lock in the last position, or fail down. When the supply pressure rises above the trip point, the 377 trip valve automatically resets, allowing the system to return to normal operation. The trip valve can be top-mounted on a manifold, yoke-mounted, or bracket-mounted to match the application requirements. 377 trip valves can be used with Fisher 480, 585C, 685, 1061, 1066, 1069, and Bettis™ G Series piston actuators.Features:Single trip valve construction reduces costs and spare part requirements of those systems using three separate switching valves to perform the failure functions. A single trip valve greatly simplifies piping requirements.Conversion to any of the fail modes requires only minor hook-up changes.The trip point is adjustable for specific supply pressure requirements.The trip valve design includes large diaphragm areas and few moving parts for efficient performance, minimum maintenance, and long service life.
