Fisherr 377 Trip Valve
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 Bettist G
Series piston actuators.
n Cost Effective—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.
n Ease of Mode Conversion—Conversion to any of the
fail modes requires only minor hookup changes.
n Adjustable Trip Valve—The trip point is adjustable
for specific supply pressure requirements.
n Reliable Operation—The trip valve design includes
large diaphragm areas and few moving parts for
efficient performance, minimum maintenance, and
long service life.
Fisher 377 Trip Valve Mounted on
Size 130 585C Actuator
377 Trip Valve