5
STEAM INJECTION INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
Principle of operation
OVERVIEW
1. Boiler steam enters the humidifier at line pressure and flows through a chamber (jacket) surrounding an inner
dispersion tube. The jacket of steam preheats the dispersion tube so that when steam enters the dispersion tube
(at Step 5 below) it does not condense as it would if the tube were cold, thereby eliminating condensation and
dripping.
2. After flowing through the steam jacket, steam with entrained condensate slows from entering the larger space of the
separator and from hitting the perimeter deflector plate, and begins to spin and separate.
3. Separated steam rises through slots in the multi-baffle plate to the separator upper region, and enters the internal
drying tube that excludes any remaining condensate, allowing only dry steam to leave the separator.
4. Separated condensate drains from the separator to the steam trap.
5. The steam valve controls the amount of steam allowed into the preheated dispersion tube. The steam valve is
typically controlled in one of two ways:
• By a signal from a building automation system
• By a humidity controller connected to the steam valve
6. Steam is discharged uniformly through the tubelets into the airstream.
OM-1170
mc_031611_0808
1
2
3
4
5
6
About right-hand and left-hand discharge:
Imagine you are standing in the duct where the Steam
Injection humidifier is to be installed, with airflow blowing
into your face:
• Specify the humidifier with right-hand discharge if the
separator is on your right.
• Specify the humidifier with left-hand discharge if the
separator is on your left.
For consistency, humidifier drawings in this catalog are
shown with right-hand discharge.
FIGURE 5-1: STEAM INJECTION HUMIDIFIER PRINCIPLE OF OPERATION
