2R2500 & 2R3500 Actuators
Installation & Maintenance Manual
1
November 13, 2013
www.atcontrols.com
Engineering\documents\products/IOM\
IOM1004.docx
2R-SERIES 2R2500 & 2R3500 DOUBLE ACTING & SPRING RETURN
SCOTCH YOKE ACTUATORS
BRIEF INTRODUCTION
TRIAC 2R2500 & 2R3500 scotch yoke actuators
have been designed and engineered to provide high cycle-life
to meet the demands of our customers. Equipped with dual
travel stops and NAMUR accessory mounting.
!!!WARNING!!!
FOR YOUR SAFETY,
IT IS IMPORTANT THAT THE
FOLLOWING PRECAUTIONS BE TAKEN BEFORE ANY
DISASSEMBLY OF THE ACTUATOR OCCURS.
1.
Depressurize the lines and cylinder of the actuator
before removing any components.
2.
On spring return actuators be careful to loosen the
end cap bolts evenly due to the preload on the
springs.
Installation of Actuator
Triac actuators are adapted to the valve by means of an
intermediate bracket and coupler. The coupler adapts the star
output of the actuator to the valve shaft. Standard mounting
kits provided for mounting the actuator in the direction of the
pipe.
After mounting the actuator, it may be necessary to adjust the
travel stops for proper open or closed valve position.
Pneumatically stroke the actuator several times to assure
proper operation with no binding of the coupler.
Air Supply
Pneumatic piping to the actuator and associated accessories
should follow the best practices for instrument pneumatic
piping systems, I.E. lines free of water, oil, pipe sealant or
other contaminants. The operating medium is to be filtered
dry air or inert gas which is filtered to 50 micron particles size
or less. It is extremely important that the actuator be powered
with the proper air pressure and air volume. Maximum
working pressure is 150 PSI.
The spring housing on spring return actuators, if not piped,
will breathe through the right hand port. It’s important that it
not be exposed to a corrosive atmosphere. Please contact A-T
Controls for possible solutions if this condition exists.
Lubrication
Triac actuators are factory lubricated for life and additional
lubrication is not normally required. However, for actuators
performing 100,000 cycles or more, an oil mist lubricator is
recommended. Oil mist lubrication requires a mineral oil type
ISO VG32 Class 1 for usage in temperature range 15 to 158
Deg. F. Oil mist lubricator must be set to the lowest setting.
Once begun, the oil mist lubrication cannot be discontinued.
CAUTION
If the actuator is equipped with a pneumatic positioner or
pneumatic controller, oil mist lubricated air cannot be used
unless the instrument manufacturer indicates that the
instrument is compatible with lubricated air.
Orientation of Pistons
Double Acting (DA)
The pistons of standard DA actuators are as shown below.
This provides for the highest torque at the “closed” valve
position for valves that rotate clockwise to close. The pistons
are then in their innermost position and the end of travel stop
can be fine ad or – 5 degrees (SEE INSTRUCTIONS
on page 2).
(DL/SAH)
Spring Return (SR)
The pistons of standard SR actuators are mounted as shown
below. Although spring force is diminished, the geometry of
the mechanism provides a greater torque at the end of the
spring stroke than at mid stroke. When the actuator is in the
“opened” valve position (springs fully compressed), the end of
travel stop can be fine ad or – 5 degrees (SEE
INSTRUCTIONS on page 2).
(SAH)
