INSTALLATION, OPERATION, &
MAINTENANCE MANUAL
TITLE:
F84L Series Liquid Relief Valve
Rev. J
Page 4 of 18
2.0
DESCRIPTION, OPERATION, SERVICE ENVELOPE,
INSTALLATION, and STARTUP
2.1
DESCRIPTION / OPERATION
CLOSED
OPEN
The FLOW SAFE F84L Series liquid relief valve is a direct-acting spring-loaded relief valve, suitable for
liquid service. The Type F84L is plastic-seated with elastomeric seals.
Orifice sizes are available in -2, -3, -4, -8, -G, and -J with set pressures from 30 to 24,277 psig (depending
on the orifice size).
Blowdown is nonadjustable, designed to be a maximum of 20% for the -3, -4, -8, -G, and –J. For the -2
orifice, blowdown may approach 30-35% whether the valve pops fully open or partially opens at low flow
rates.
OUTLET
SPINDLE
SEAT (PLASTIC)
(Balanced against
backpressure)
HUDDLING
CHAMBER
Fully open
at 7.5%
overpressure
BODY
PRESSURE
ADJUSTMENT
(PA) SCREW
INLET
SPRING
PRESSURE ASSIST
DRAG SEAL
(ELASTOMER)
BONNET
LIFT
ATMOSPHERIC
VENT
STATIC
BACKFLOW SEAL
(ELASTOMER)
BUSHING