Data Sheet

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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).

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.

X0648

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.

VBL Volume Booster

D103393X012

Product Bulletin

62.3:VBL

February 2014

Summary of content (8 pages)

PAGE 1
Product Bulletin VBL Volume Booster 62.3:VBL February 2014 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.
PAGE 2
Product Bulletin VBL Volume Booster 62.3:VBL February 2014 D103393X012 Specifications Input Signal Maximum Flow Coefficients See table 1 Positioner output Maximum Input Signal Pressure(1) VBL-1 and VBL-3: 5.5 bar (80 psig) VBL-2 and VBL-4: 10.
PAGE 3
Product Bulletin VBL Volume Booster 62.3:VBL February 2014 D103393X012 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.
PAGE 4
Product Bulletin VBL Volume Booster 62.3:VBL February 2014 D103393X012 Figure 2. Typical Installation with Piston Actuator PIPE NIPPLE VBL VOLUME BOOSTER SUPPLY SIGNAL TOP CYL BOTTOM CYL ACTUATOR 67D, 67DR, OR 95H REGULATOR E1212 POSITIONER Figure 3.
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Product Bulletin VBL Volume Booster 62.3:VBL February 2014 D103393X012 Installation Figures 2 and 3 show typical installations for the VBL volume booster on piston and diaphragm actuators. A single regulator that supplies both the positioner and booster (or boosters) is recommended. The supply medium must be clean, dry, oil-free air or non-corrosive gas.
PAGE 6
Product Bulletin 62.3:VBL February 2014 Ordering Information Specify stroking speed information when being mounted at the factory, for proper tuning of the instruments. Specify either critical or non-critical stroke speed time. Note Critical stroke speed time example: valve to stroke in both directions in 4 seconds or less. Non-critical stroke speed time example: valve to stroke in approximately 4 seconds in both directions.
PAGE 7
VBL Volume Booster D103393X012 Product Bulletin 62.
PAGE 8
Product Bulletin 62.3:VBL February 2014 VBL Volume Booster D103393X012 Neither Emerson, Emerson Process Management, nor any of their affiliated entities assumes responsibility for the selection, use or maintenance of any product. Responsibility for proper selection, use, and maintenance of any product remains solely with the purchaser and end user. Fisher and FIELDVUE are marks owned by one of the companies in the Emerson Process Management business unit of Emerson Electric Co.