Data Sheet
Bulletin 74.1:T205B
3
Features
Eliminates setpoint
changes caused by varying inlet pressure. This design
provides smooth opening of the plug for stable ow
and greater regulating ow capacity.
Highly sensitive to changes in
tank pressure. Available in various materials to suit
different applications.
Applicable for low pressure setting as
low as 1 inch water column / 2.5 mbar. Type T205B
reacts quickly in changing tank vapor pressure due to
direct-operated construction.
Type T205B has a large effective diaphragm area that
detects small pressure change and provides accurate
control at low pressure setting. Type T205B is a lever
style regulator; this regulator style increases force
for lockup, thus, shut off can be attained with small
lockup pressure.
Available construction
to meet NACE MR0175-2002.
Refer to Figure 2. Type T205B tank blanketing
regulator controls the vapor space pressure over a
stored liquid. When liquid is pumped out of the tank or
vapors in the tank condense, the pressure in the tank
decreases. Tank pressure is sensed by the actuator
diaphragm. Spring force pushes the pusher post
assembly, the valve disk moves away from the orice,
allowing the blanketing gas ow to increase.
When pressure in the tank increases, the actuator
diaphragm is pushed. Through the action of the
pusher post assembly, lever and valve stem, the valve
disk moves closer to the orice reducing blanketing
gas ow.
The regulator plug is balanced (inlet pressure
creates equal upward and downward forces on these
components), therefore, the outlet (control) pressure of
the unit is not affected by inlet pressure variation.
Figure 2. Type T205B Operational Schematic
Type T205B Tank Blanketing Regulator
MXXXX
November 2012
Type T205B
INLET PRESSURE
OUTLET PRESSURE
ATMOSPHERIC PRESSURE
INLET PRESSURE
OUTLET PRESSURE
ATMOSPHERIC PRESSURE
LOADING PRESSURE