Available Configurations
When supply pressure falls below the trip point,
377D Trip Valve:Fails actuator piston down. Includes
check valve and volume tank.
377L Trip Valve:Locks actuator piston in the last
position.
377U Trip Valve:Fails actuator piston up. Includes
check valve and volume tank.
377CW Trip Valve:Fails fully clockwise to close the
valve. Requires check valve and volume tank. Trip
valve moves piston to either up/down position and
requires actuator configuration for actual clockwise
movement.
377CCW Trip Valve: Fails fully counterclockwise to
close the valve. Requires check valve and volume
tank. Trip valve moves piston to either up/down
position and requires actuator configuration for
actual counterclockwise movement.
All 377 trip valves can be converted to any of the
above fail modes with minor hookup changes
Allowable Supply Pressure for Trip Valve(1)
Maximum:10.3 bar (150 psig)
Minimum:3.8 bar (55 psig)
Outlet Pressure(1)
Normal Operation:Pressure from control device
Fail‐Up or Fail‐Down Mode:Maximum volume tank
pressure
Lock‐In‐Last‐Position:Respective cylinder pressure
Trip Point
(2)
Adjustable from a minimum of 2.8 bar (40 psig) to a
maximum of 72 percent of supply pressure;
see figure 1
Reset:12.5 to 33 percent above adjusted trip point
Flow Coefficients (Cv)
(3)
Depends on flow path (shown in figure 3) as follows:
Port A to Port B and Port D to Port E: 0.5
Port B to Port C and Port E to Port F: 0.6
Body Connections
1/4 NPT internal
Temperature Capabilities
(1)
Nitrile Diaphragms and O‐Rings:-40 to 82°C
(-40 to 180°F)
Fluorocarbon Diaphragms and O‐Rings:-18 to 104°C
(0 to 220°F)
Volume Tank Maximum Internal Working Pressure
(for 377D, 377U, 377CW and 377CCW trip valves)
Standard:10.3 bar (150 psig) for non‐ASME approved
applications
(4)
ASME Approved Applications:Rated 10.3 bar (150
psig), maximum; 9.3 bar (135 psig), recommended
Volume Tank Sizing
See sizing section
Hazardous Area Classification
Complies with the requirements of ATEX Group II
Category 2 Gas and Dust
377 SST
Safety Instrumented System Classification
SIL 3 capable - certified by exida Consulting LLC
