Data Sheet

VBL Volume Booster
D103393X012
Product Bulletin
62.3:VBL
February 2014
3
Principle of Operation
Refer to figures 1, 2, and 3. Because of the restriction,
large input signal changes register on the booster
input diaphragm sooner than in the actuator. A large,
sudden change in the input signal causes a pressure
differential to exist between the input signal and the
output of the booster. When this occurs, the
diaphragms move to open either the supply port or the
exhaust port, whichever action is required to reduce
the pressure differential. The port remains open until
the difference between the booster input and output
pressures returns to within the deadband limits of the
booster. With the bypass restriction adjusted for stable
operation, signals having small magnitude and rate
changes pass through the bypass restriction and into
the actuator without initiating booster operation.
Both the supply and exhaust ports remain closed,
preventing unnecessary air consumption and possible
saturation of positioner relays.
Figure 1. Volume Booster Sectional View
GE26237-Section
UPPER DIAPHRAGM
DIAPHRAGM PLATE
ASSEMBLY (INCLUDES
LOWER DIAPHRAGM)
DIAPHRAGM SPACER
LOWER SPRING
VALVE PLUG ASSEMBLY
LUBRICANT
HOUSING, TOP
HEX SCREW
EXHAUST PORT
EXHAUST
OUTPUT TO
ACTUATOR
SUPPLY PORT
END CAP
SPRING SEAT
UPPER SPRING
BYPASS RESTRICTION
ADJUSTING SCREW
SUPPLY
HEX NUT
PIN, SLOTTED
SPRING
BYPASS VALVE
O‐RING
HOUSING, BOTTOM
O‐RING
INPUT
SIGNAL