VALVE ACTUATORS
DOE-HDBK-1018/2-93
Valves
VALVE ACTUATORS
Some type of actuator is necessary to allow for the positioning of a valve.
Actuators vary from simple manual handwheels to relatively complex electrical
and hydraulic manipulators.
EO 1.6
DESCRIBE the construction and principle of operation for the
following types of valve actuators:
a.
Manual
b.
Electric motor
c.
Pneumatic
d.
Hydraulic
e.
Solenoid
Introduction
Valve actuators are selected based upon a number of factors including torque necessary to operate
the valve and the need for automatic actuation. Types of actuators include manual handwheel,
manual lever, electrical motor, pneumatic, solenoid, hydraulic piston, and self-actuated. All
actuators except manual handwheel and lever are adaptable to automatic actuation.
Manual, Fixed, and Hammer Actuators
Manual actuators are capable of
Figure 30 Fixed Handwheel
placing the valve in any position but
do not permit automatic operation.
The most common type mechanical
actuator is the handwheel.
This
type includes handwheels fixed to
the stem, hammer handwheels, and
handwheels connected to the stem
through gears.
Handwheels Fixed to Stem
As
illustrated
in
Figure
30,
handwheels fixed to the stem
provide
only
the
mechanical
advantage of the wheel.
When
these valves are exposed to high operating temperatures, valve binding makes operation difficult.
ME-04
Rev. 0
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