Miscellaneous Mechanical Components
DOE-HDBK-1018/2-93
STEAM TRAPS
Although there are several variations of the orifice-type steam trap, each has one thing in
common; it contains no moving parts. One or more restricted passageways or orifices allow
condensate to trickle through, but do not allow steam to flow through. Some orifice-type steam
traps have baffles in addition to orifices.
Summary
The following important information in this chapter is summarized below.
Steam Traps Summary
A steam trap consists of a valve and a device or arrangement that causes the valve
to open and close as necessary to drain the condensate from the lines without
allowing the escape of steam. Steam traps are installed at low points in the system
or machinery to be drained.
The type of steam trap used depends primarily on its application. Types include ball
float, bucket traps, thermostatic traps, bellows-type traps, impulse traps, and orifice-
type traps.
Impulse steam traps pass steam and condensate through a strainer before entering the
trap. A circular baffle keeps the entering steam and condensate from impinging on
the cylinder or on the disk. The impulse type of steam trap is dependent on the fact
that hot water under pressure tends to flash into steam when the pressure is reduced.
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