Fisher 2625 2625NS Volume Boosters
Fisher 2625 series volume boosters are used in conjunction with a
positioner on a throttling control valve to increase stroking
speed. The 2625NS is a nuclear service version and uses elastomeric
components that better withstand high temperature and radiation
environments. The 2625 and 2625SST are certified for use in Safety
Instrumented System (SIS) applications. Certification is by exida
Consulting LLC, a global provider of functional safety and control
system security.
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 either 2625 or 2625NS
volume booster for diagnostic testing.
The 2625 is certified for use in Safety Instrumented System (SIS)
applications. Certification is by exida Consulting LLC, a global
provider of functional safety and control system security. SIS
certification is identified on the product by a label affixed to
the ower housing.
| Certifications | ATEX, CUTR |
| Diagnostics | No |
| Input Signal | Pneumatic |
| Max Outlet Pressure | 150 psi |
| Mounting Type | Actuator Mount |
| Operating Temperature | Standard Temperature, High Temperature |
| Position Control | Modulating Control |
| Safety Certification | SIL 3 capable |
| Supply Media | Air, Natural Gas |
Specifications
Supply Pressure Ranges
When used in conjunction with a positioner or other pneumatic
accessory, always pipe the positioner and volume booster with one
common supply through a Fisher 67D, 67DR, or 95H regulator . 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. Constructions
are available in two maximum supply ranges.When Normally Used With
Diaphragm Actuators: Up to 2.8 bar (40 psig) When Normally Used
With Piston Actuators: Up to 10.3 bar (150 psig)
Input Signal Pressure
Positioner output
Maximum Input Signal Pressure
10.3 bar (150 psig)
Fixed Input‐to‐Output Pressure Ratio
1 to 1
Nominal Deadband
Percent of Positioner Output Span(1):
2.4 mm (0.094 inch) exhaust port: 2%
9.5 mm (0.375 inch) exhaust port: 3.5%
12.7 mm (0.5 inch) exhaust port: 5%
