COPES-VULCAN INSTRUCTION MANUAL
MODEL 700 DIRECT-ACTING ACTUATOR
Rev.5 (08/10) Page 4 of
20 Form 01:P224:37
1.0 INTRODUCTION
1.1 SCOPE OF MANUAL
This instruction manual provides instructions for all sizes of the direct-acting Model 700 actuator and
includes instructions for top-mounted handwheels, side-mounted handwheels, adjustable travel stops
and fixed travel stops.
1.2 DESCRIPTION
The Model 700 direct-acting pneumatic actuator is a spring-opposed diaphragm actuator that is used
for the operation of control valves. The actuators are available in sizes 60, 100, 160, and 160-5, with
travel up to 5" (125 mm).
For the direct-acting actuator, the spring tends to retract the actuator stem and air pressure acting on
the diaphragm will extend the actuator stem. The initial spring force, or spring preload, is adjustable
and, for the case of a direct-acting actuator on a direct-seated valve, the preload is normally set to a
low value. The spring preload can be expressed as the diaphragm pressure at which stem movement
begins.
The actuator can be attached to the valve bonnet with a screwed ring or with four studs. The valve
stem is connected to the actuator by use of a threaded ring which is locked between surfaces of the
stem connector.
The top-mounted handwheel is designed to extend the actuator stem against the spring force but not
to retract the actuator stem.
The side-mounted handwheel is a worm gear coupled to an ACME thread and provides a large
mechanical advantage and the means to both extend and retract the actuator stem.
Two different types of travel stops can be supplied: an adjustable up/down stop and a fixed down
stop. The up stop provides a means of preventing the actuator from fully retracting, while the down
stop prevents the actuator from fully extending.
For control valve applications, the actuator will almost always require a positioner.
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