Valves
DOE-HDBK-1018/2-93
TYPES OF VALVES
Check Valves
Check valves are designed to prevent the reversal of flow in a piping system. These valves are
activated by the flowing material in the pipeline. The pressure of the fluid passing through the
system opens the valve, while any reversal of flow will close the valve. Closure is accomplished
by the weight of the check mechanism, by back pressure, by a spring, or by a combination of
these means. The general types of check valves are swing, tilting-disk, piston, butterfly, and
stop.
Swing Check Valves
A swing check valve is illustrated in Figure 22. The valve allows full, unobstructed flow and
automatically closes as pressure decreases. These valves are fully closed when the flow reaches
zero and prevent back flow. Turbulence and pressure drop within the valve are very low.
A swing check valve is normally recommended for use in systems employing gate valves because
Figure 22 Swing Check Valve
of the low pressure drop across the valve. Swing check valves are available in either Y-pattern
or straight body design. A straight check valve is illustrated in Figure 22. In either style, the
disk and hinge are suspended from the body by means of a hinge pin. Seating is either metal-to-
metal or metal seat to composition disk. Composition disks are usually recommended for
services where dirt or other particles may be present in the fluid, where noise is objectionable,
or where positive shutoff is required.
Rev. 0
ME-04
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