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TYPES OF VALVES
DOE-HDBK-1018/2-93
Valves
Globe Valve Body Designs
The three primary body designs for globe valves are Z-body, Y-body, and Angle.
Z-Body Design
The simplest design and most common for water applications is the Z-body. The Z-body
is illustrated in Figure 9. For this body design, the Z-shaped diaphragm or partition
across the globular body contains the seat. The horizontal setting of the seat allows the
stem and disk to travel at right angles to the pipe axis. The stem passes through the
bonnet which is attached to a large opening at the top of the valve body. This provides
a symmetrical form that simplifies manufacture, installation, and repair.
Y-Body Design
Figure 10 Y-Body Globe Valve
Figure 10 illustrates a typical
Y-body globe valve.
This
design is a remedy for the high
pressure drop inherent in globe
valves. The seat and stem are
angled at approximately 45°.
The angle yields a straighter
flowpath (at full opening) and
provides the stem, bonnet, and
packing a relatively pressure-
resistant envelope.
Y-body globe valves are best
suited for high pressure and
other severe services. In small
sizes for intermittent flows,
the pressure loss may not be as
important
as
the
other
considerations favoring the
Y-body design.
Hence, the
flow passage of small Y-body
globe valves is not as carefully
streamlined as that for larger
valves.
ME-04
Rev. 0
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