Fi-sher 377 Pneumatic Pressure Trip Valve Control Valve Safety Device Valve Trip Valve
Fi-sher 377 Series Trip Valve
The Fi-sher 377 pressure-sensing trip valve provides automatic fail-safe action for pneumatic actuators when instrument air supply pressure drops below a predetermined level. Upon recovery of supply pressure, the unit resets automatically to restore normal control.
Product Overview
A single 377 trip valve can perform the functions that previously required multiple switching valves, reducing complexity and spare parts. Fail modes (up, down, or lock-in-last-position) are selectable with minor piping changes. The design emphasizes large diaphragms, minimal moving parts, and durable construction in aluminum or stainless steel. It is suitable for use with Fi-sher 480, 585C, 685, 1061 and similar piston actuators, with mounting options for manifold, yoke, or bracket installation.
Technical Specifications
| Specification | Details |
|---|---|
| Product | Fi-sher 377 Pressure-Sensing Trip Valve |
| Fail Modes | Fail-down (377D), Lock-in-last (377L), Fail-up (377U), Clockwise/Counterclockwise close (377CW/CCW) |
| Max Supply Pressure | 10.3 bar (150 psig) |
| Min Supply Pressure | 3.8 bar (55 psig) |
| Trip Point Range | 2.8 bar (40 psig) minimum up to 72% of supply |
| Connections | 1/4 NPT |
| Temperature Capabilities | Nitrile seals -40 to 82°C; Fluorocarbon seals -18 to 104°C |
| Materials | Housing: Aluminum or SST; Diaphragms/O-rings: Nitrile or Fluorocarbon |
| Certifications | ATEX, CUTR; SIL 3 capable version available |
| Weight | Approx. 0.95 kg (aluminum) / 2.31 kg (SST) |
Application Industry
Applied in process plants requiring reliable actuator protection, including refining, petrochemical, power, and general industrial control systems that depend on instrument air.
Common Problems
Common issues include incorrect volume tank selection for fail-up/down modes or mismatch between trip setting and system pressure. Proper configuration and the unit’s adjustable trip point help resolve these during installation and commissioning.
Replacement Models
Compatible as a replacement for other Fi-sher trip valves or similar pressure-sensing protection devices in existing actuator systems.
Why Buy From Us
We focus on authentic Em-erson Fi-sher instrumentation and provide knowledgeable assistance for trip valve selection and application matching.
Stock & Delivery Time
Standard lead time is 6-8 weeks.
RFQ Form
Submit your required fail action, actuator model, operating pressure, temperature conditions, and material needs for a detailed quote.
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