2
Anderson Greenwood
SerieS 95 Pilot oPerated Safety relief ValVeS
InstallatIon and MaIntenance InstructIons
1 GenerAl VAlVe description
Refer to Figure 1
the anderson Greenwood Series 95 Valve
consists of a main valve and pilot. the main
valve has an unbalanced piston with o-ring
seat. tank pressure is applied to the top of the
piston by means of the pilot. the area of the top
of the piston is larger than the bottom and the
valve remains closed.
When the tank pressure increases to the
set pressure of the pilot, the pilot opens and
vents the pressure from the top of the piston.
the force acting on the bottom of the piston is
now greater than that acting on the top and the
valve opens.
When the tank pressure decreases to the
closing pressure of the pilot, the pilot closes
and tank pressure is directed to the top of the
piston. the force acting on the top of the piston
is now greater than the force on the bottom and
the valve closes.
fiGure 1
P (tank)
P (tank)
field test
auxiliary setting device
Bonnet vent
Check
valve
tank pressure
sense line
Main valve
unbalanced
piston
dome (top of the piston)
Pilot vent
Pilot
inlet (tank pressure)
o-ring seat
outlet
