Data Sheet

Bulletin 74.2:T208
2
Available Congurations
Type T208: Tank Blanketing Vapor Recovery regulator
with control pressure range of 2 in.w.c. to 7 psig /
5 mbar to 0.48 bar in six different spring ranges
and has internal pressure registration requiring no
control line.
Type T208M: Similar to Type T208 but has a blocked
throat and a control line connection for external
pressure registration.
Body Sizes and End Connection Styles
See Table 1
Maximum Allowable Inlet (Casing) Pressure
(1)
See Table 1
Maximum Outlet Pressure
(1)
35 psig / 2.4 bar
Maximum Emergency Inlet Pressure to Avoid Internal
Parts Damage
(1)
With Nitrile (NBR) or Fluorocarbon (FKM)
diaphragm: 35 psig / 2.4 bar
With Fluorinated Ethylene Propylene (FEP)
diaphragm: 10 psig / 0.69 bar
Control Pressure Ranges
(1)
See Table 3
Flow and Sizing Coefcients
See Table 4
C
v
Coefcients and Flow Capacities
See Table 5
Orice Size
7/16 in. / 11 mm
Body and Casing Materials
Gray Cast Iron, WCC Carbon Steel and
CF8M/CF3M Stainless Steel
(2)
Trim Materials
See Table 2
Material Temperature Capabilities
(1)(3)
Elastomer Parts
Nitrile (NBR): -40 to 180°F / -40 to 82°C
Fluorinated Ethylene Propylene (FEP): -20 to 180°F /
-29 to 82°C
Fluorocarbon (FKM): 40 to 300°F / 4 to 149°C
Ethylene Propylene Diene (EPDM): -20 to 225°F /
-29 to 107°C
Peruoroelastomer (FFKM): 0 to 300°F / -18 to 149°C
Body Materials
Gray Cast Iron: -20 to 300°F / -29 to 149°C
WCC Carbon Steel: -20 to 300°F / -29 to 149°C
CF8M/CF3M Stainless Steel: -40 to 300°F /
-40 to 149°C
Spring Case Vent Connection
1/4 NPT
Diaphragm Case Control Line Connection (Type T208M)
1/2 NPT
Approximate Weight
17.7 lbs / 8 kg
1. The pressure/temperature limits in this Bulletin and any applicable standard or code limitation should not be exceeded.
2. Pipe nipples and anges are 316 Stainless steel for anged body assemblies.
3. See Table 2 for operating temperature ranges for available trim combinations.
Specications
This section lists the specications of the T208 Series Tank Blanketing Vapor Recovery Regulator. Factory specication, such
as maximum temperature, maximum inlet and outlet pressures, spring range and seat or orice size are stamped on the
nameplate fastened on the regulator at the factory.
Introduction
The T208 Series are direct-operated tank blanketing vapor
recovery regulators. These regulators are used to sense
an increase in vessel pressure and vent excessive internal
tank pressure to an appropriate vapor recovery disposal
or reclamation system. T208 Series may also be used as
backpressure regulators or relief valves.
Principle of Operation
Type T208 vapor recovery regulator senses the change in
tank pressure internally (see Figure 2), while Type T208M
regulator senses the change in tank pressure through a
1/2 NPT control line tapped in its lower casing (see Figure 3).
When vessel pressure increases above the setpoint of the
regulator due to thermal heating or pump-in of the product, the
pressure on the diaphragm overcomes the force of the control
spring. The disk moves away from the orice, allowing gas to
ow from the vessel to the vapor recovery system.
As vessel pressure is reduced, the force of the back disk spring
causes the disk to move toward the orice, decreasing the ow
of gas out of the vessel. As vessel pressure drops below the
setpoint of the regulator, the disk will seat against the orice,
shutting off the gas ow.
Table 1. Body Sizes, End Connection Styles and Maximum Allowable Inlet (Casing) Pressures
BODY SIZE
BODY MATERIAL END CONNECTION STYLE
(1)
MAXIMUM ALLOWABLE INLET (CASING) PRESSURE
In. DN psig bar
3/4 or 1 20 or 25
Gray cast iron NPT 35 2.4
WCC Carbon steel
NPT, CL150 RF, CL300 RF or
PN 16/25/40 RF
75 5.2
CF8M/CF3M Stainless steel
(2)
1. All flanges are welded. Weld-on flange dimension is 14 in. / 356 mm face-to-face.
2. Pipe nipples and anges are 316 Stainless steel for anged body assemblies.