Xylem Bell & Gossett Hoffman Speciality Series Engineering Data Manual page 22

Installation of drip trap ahead of riser or expansion joint
STATIC
HEAD
Installation of drip trap in long run of steam piping or ahead of control valves
STATIC
HEAD
Trapping Ahead of Steam
Regulators
When steam pressure or temperature regula-
tor valves are installed in a steam line, con-
densate may back up ahead of the valve
when it is off. When the valve opens with con-
densate backed up on the inlet side, the con-
densate will cause water hammer.
Where the branch connection to a control
valve is less than 10 ft., the branch line may
pitch toward the steam main to allow conden-
sate to flow back into main.
When the branch line is over 10 ft., pitch the
branch line toward the control valve and
install a steam trap. The steam trap should
be as close to the control valve as possible.
TRAP
SHUT-OFF
VALVE
"Y" STRAINER
TRAP
SHUT-OFF
VALVE
"Y" STRAINER
10' OR LESS
PITCH TOWARD STEAM
MAIN 1/2" PER FOOT
STEAM
MAIN
OVER 10'
PITCH TOWARD
STEAM MAIN
1/2" PER FOOT
STEAM
MAIN
SHUT-OFF
VALVE
SHUT-OFF
VALVE
TRAP
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