Emerson Fisher VBL Data Sheet
VBL Volume Booster
D103393X012
Fisherr VBL Volume Booster
The Fisher VBL volume booster is used in conjunction
with a positioner on a throttling control valve to
increase stroking speed.
The booster incorporates fixed deadband, soft seat
construction, and an integral bypass restriction to
eliminate positioner saturation problems that can
occur with volume boosters that do not have these
features. Adjustment of the integral bypass restriction
is necessary for system stability. This adjustment does
not affect the deadband of the volume booster, but
does permit the control valve to respond to small input
signal changes without sacrificing steady-state
accuracy. It also allows the booster to deliver
high-volume output for fast stroking when large, rapid
input signal changes occur.
The volume booster is used to improve stroking speed.
If precision valve control is required, the use of a
positioner is recommended. If the volume booster is to
be used only with an actuator, for on-off control, the
integral bypass restriction on the booster must be
closed (turned fully clockwise).
X0648
Product Bulletin
62.3:VBL
February 2014
Connectors and piping can be installed with the VBL
volume booster for diagnostic testing.
Features
n Fast Response—Booster delivers the volume needed
for rapid actuator stroking when large input
changes suddenly occur.
n Adjustable Response—Integral bypass restriction
tunes the booster response so that smooth actuator
motion follows the slow signal changes.
n Efficient Operation—Soft seats provide tight shutoff
to reduce unnecessary air consumption and
eliminate saturation of positioner relays.
n Maintains Accuracy—Booster permits high actuator
stroking speeds upon demand without degrading
the positioner steady-state accuracy.
www.Fisher.com
Product Bulletin
62.3:VBL
February 2014
Specifications
VBL Volume Booster
D103393X012
Input Signal
Positioner output
Maximum Input Signal Pressure
VBL-1 and VBL-3: 5.5 bar (80 psig)
VBL-2 and VBL-4: 10.3 bar (150 psig)
(1)
Maximum Flow Coefficients
See table 1
Connections
Input Signal: 1/4 NPT
Supply and Output: 1/2 NPT
Hazardous Area Classification
Input to Output Pressure Ratio
Fixed at 1 to 1
Supply Pressure Ranges
(1)
Complies with the requirements of ATEX Group II
Category 2 Gas and Dust
When used in conjunction with a positioner or other
pneumatic accessory, always pipe the positioner and
booster with one common supply through a Fisher
67D, 67DR, or 95H regulator (see figure 2). A
high-capacity filter, such as the Fisher 262K, should
be installed in the supply line to the regulator. Supply
pressure also must not exceed the maximum
pressure rating of the actuator.
Operative Temperature Limits
(1)
-40 to 93_C (-40 to 200_F)
NOTE: Specialized instrument terms are defined in ANSI/ISA Standard 51.1 - Process Instrument Terminology.
1. The pressure/temperature limits in this document and any applicable code or standard should not be exceeded.
Construction Materials
Body: Aluminum
Diaphragms: HNBR with nylon fabric
Upper and Lower Valves: HNBR
O-Rings: HNBR
Connectors for Diagnostic Testing:
or
Approximate Weight
1.0 kg (2.2 lb)
JStainless steel
Jbrass
Table 1. Maximum Flow Coefficients
Instrument
VBL‐1 volume booster 2.5 1.1
VBL-2 volume booster 2.5 1.1
VBL‐3 volume booster 2.5 1.8
VBL-4 volume booster 2.5 1.8
FIELDVUEt DVC6200, DVC6200 SIS, DVC6200f, DVC6200p,
DVC6000, DVC6000 SIS, DVC6000f digital valve controllers
FIELDVUE DVC2000 digital valve controller:
Low pressure relay
High pressure relay
Fisher 3570 valve positioner 0.25 0.25
Fisher 3582 valve positioner 0.17 0.19
Fisher 3610J, 3610JP, 3611JP, 3620J, 3620JP, 3621JP valve
positioners
Supply Port Coefficients Exhaust Port Coefficients
C
v
0.37 0.31
0.13
0.19
0.37 0.30
C
0.15
0.20
v
2
VBL Volume Booster
D103393X012
Product Bulletin
62.3:VBL
February 2014
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
Figure 1. Volume Booster Sectional View
SPRING SEAT
HEX NUT
BYPASS RESTRICTION
ADJUSTING SCREW
UPPER SPRING
INPUT
SIGNAL
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.
HOUSING, TOP
EXHAUST PORT
HEX SCREW
UPPER DIAPHRAGM
DIAPHRAGM SPACER
HOUSING, BOTTOM
GE26237-Section
PIN, SLOTTED
SPRING
BYPASS VALVE
O‐RING
SUPPLY
O‐RING
END CAP
DIAPHRAGM PLATE
ASSEMBLY (INCLUDES
LOWER DIAPHRAGM)
EXHAUST
SUPPLY PORT
OUTPUT TO
ACTUATOR
LOWER SPRING
VALVE PLUG ASSEMBLY
LUBRICANT
3
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