Page 80 - Instrumentation and Measurement
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FIGURE 5.21 Body globe valve: (A) single and (B) double seated.
Figure 5.22 shows the basic elements of a common form of such a control valve. The term globe
valve is used because of their spherical bodies, though some modern valves no longer have much of
a spherical shape. The two halves of their body are separated by an internal baffle which has an
opening that forms a seat through which a movable plug can be moved to close the valve. The plug
is connected to a stem which is moved by an actuator assembly.
FIGURE 5.22 Direct action: (A) air pressure increase to close and (B) air pressure increase to open.
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