Emerson Fisher 377 Stainless Steel Pressure Sensing Trip Valve Diaphragm Pneumatic Actuator DVC2000 DVC6200 Valve Positioners

Everyone talks digital safety systems, but when the turbine trips or the air supply drops, the last line of defense is still a Fisher 377. It sees the signal drop below 2.5 psi (or whatever you set) and instantly dumps the actuator air so the valve slams to its fail position. No electricity, no solenoid, no software – just pure pneumatic reliability. Thousands are still running on steam turbines, compressor anti-surge valves and boiler FD fans.

• Three separate trip valves in one body – majority voting
• Adjustable trip point 15–100 psi
• Big 1/2" or 3/4" ports – vents huge actuators in under 2 seconds
• Aluminum body, stainless internals – lasts forever
• Manual push-button test on the side
• Works upside-down, sideways, any position

• Steam turbine bypass valves
• Compressor anti-surge valves
• Boiler forced-draft fan dampers
• Gas turbine fuel control backup

Q: Do you still make the 377?
A: Yes – brand new units ship every week from Marshalltown.

Q: Can I replace it with a solenoid?
A: You can, but most plants keep the 377 as backup – solenoids sometimes stick.

Q: Spare parts?
A: Diaphragms and o-rings still in stock, same as 1980.

Phone: +8615000725058
Email: edwardzhao@gbsxj.com

• Fisher 377L – lock-up version (holds position)
• Fisher 377D – dump on low signal only
• Fisher 377U – dump on high signal