| By Aekawat Joorong
Bettis Actuator representative Thailand
In developing the G-Series actuators, Bettis improved a basic
concept - the reaction bar, by adding state-of-the-art Powr-Swivl,
replaceable bearings that feature an efficient wear and corrosion
resistant coating system, and tension rod compressed spring.
This enhanced design significantly improves efficiency, reduces
wear and extends the actuator's life. Typical applications
would include the automation of ball, butterfly and plug valves,
louvers and dampers and quarter-turn mechanisms.

The piston rod connection is contained by the guide block,
which is supported by a high strength alloy steel reaction
bar treated to provide a highly corrosion and wear-resistant
finish. The superior surface finishes and self-lubricating
bearings maximise the transfer of input energy directly to
the valve stem. The tension-loaded spring minimises radial
loads on the piston rod, further enhancing efficiency.
G-Series models are qualified by accelerated wear testing.
The actual service life may be predicted based upon specific
application parameters and environmental conditions. Proper
actuator selection, enhanced by proprietary data analysis
methods, allows optimum performance and operating economy.
Low friction, permanently lubricated, high performance bearings
protect sliding and rotating components, significantly extending
actuator life.
G-Series actuators incorporate protective internal and external
coatings, assuring the actuator's reliable operation in the
harshest of environments. The actuator exhibits excellent
corrosion resistance, confirmed by salt spray testing per
ASTM B117 criteria. Construction features prevent water ingress,
allowing the actuators to meet IP66 and IP67M specifications
and severe high-pressure water deluge test.
Safe installation and removal of the spring module is facilitated
by the design. It incorporates Bettis' Tension-Lok, which
allows for the removal of the spring module in a manner that
eliminates accidental release of the spring force. Each module
is tagged with detailed product information, minimising the
potential for incorrect installation, operation, or misapplication
of a reconfigured actuator.
The ease of interchanging the power and spring modules allows
quick reversal of the 'fail-safe' mode, while providing for
the addition of overrides, accessories and other modules.
For instance, the actuator may be easily altered from a single-acting
to double-acting power cylinder configuration, and/or a hydraulic
manual override may be added after the actuator has been installed.
Field serviceable modules include the drive, power, spring
and override. They are removable, serviceable and interchangeable
without removing the actuator from the valve. This procedure
requires no special tools or disassembly of any module, reducing
the required plant shutdown time for service. Modules may
be replaced as an assembly or serviced at the client's maintenance
facility - and all modules may be purchased separately or
in any combination. This feature allows reduced parts and
spares inventory at the distribution facility, while increasing
the availability of different model configurations.
For more information contact http://www.bettis.com
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