FISHER – 377sensing trip valve series – Sensing Adjustable Trip Valves in Aluminum and Stainless Steel

The FISHER 377 series is not a traditional pressure regulator but a pressure – sensing trip valve series. It is suitable for control applications where a specific valve or actuator action is required when the supply pressure falls below a specific point. Here is its introduction:
Working Principle: During normal operation, the supply pressure is applied to the upper diaphragm of the trip valve. The valve core spring ensures that the exhaust port is closed. At the same time, the pressure is applied to the lower diaphragm through the throttle valve, causing the valve core assembly to move and connect the corresponding valve ports. The normal control pressure of the actuator flows from the control device to the cylinder. When the supply pressure is lower than the trip point, the trip valve will have different actions in different modes. For example, in the fail – down mode, the exhaust port opens to release the supply pressure applied to the lower diaphragm, causing the valve core assembly to act, shut off the normal pressure, the pressure of the gas storage tank flows to the top of the actuator cylinder, and the pressure at the bottom of the cylinder is released, forcing the piston to move downward. After the supply pressure is restored, the trip valve resets.
Features:
Cost – effective: Compared with the system using three separate switching valves to perform the failure function, a single trip valve can reduce costs and spare part requirements, and greatly simplify the piping requirements.
Convenient mode conversion: Converting to any failure mode only requires a minor connection change.
Adjustable trip point: The trip point can be adjusted according to specific supply pressure requirements.
Reliable operation: The design includes a large diaphragm area and few moving parts, which can improve the effective performance, reduce the maintenance requirements and prolong the service life.
Installation method: It can be top – mounted on a manifold, yoke – mounted, or bracket – mounted to meet the application requirements.
Compatible actuators: It can be used with Fisher 480, 585C, 685, 1061, 1066, 1069 and Bettis G – series piston actuators.