Steam Generation; Steam Distribution - Nortec NHTC Installation And Operation Manual

How the Humidifier Works
The NHTC/PC is an atmospheric steam generator that uses heat generated by electrical current
flowing between submerged electrodes to generate heat and steam. The NHTC/PC is designed
for air humidification via steam distributor, blower pack, or steam manifold (SAM-e).

Steam Generation

 Once the unit receives a demand signal, the door interlock switch is closed, and the safety
loop between terminal 1 and 2 is closed the humidifier closes the contactor and measures
the current.
 If the demand is lower than the actual output the inlet valve is kept closed and output is
reduced by letting the water level in the cylinder decrease by evaporation.
 If demand is higher than the actual output after a brief delay the fill valve is activated and
water flows into the fill cup. Water from the fill cup flows into the bottom of the cylinder
through a hose connected to the drain valve housing.
Note: The cylinder is gravity fed from the fill cup. If backpressure from the steam line is too
high it will cause water to back up in the fill cup and flow down the overflow line to the
drain.
 ·As soon as the water in the cylinder comes in contact with the energized electrodes current
flows through the water. The resistance of the water to the electrical current heats the
water and turns it to steam. The more electrode is covered by water the higher is the
current and output. The unit continues to fill until the current matches demand or the high
water sensor detects a high water level.
 The NHTC/PC repeats the fill and boil down cycle repeatedly to match output to demand.
 Over time minerals in the water will adhere to the cylinder's electrodes. The humidifier will
automatically fill to a higher water level to maintain full capacity during the life of the
cylinder. Eventually because of scale formation it will no longer be possible for the
humidifier to reach its full capacity. The NHTC/PC's software monitors this condition and will
display a warning when the cylinder needs to be replaced.
Drains
 As steam is produced minerals are left behind increasing the conductivity of the water. The
NHTC/PC's patented auto adaptive cycle will monitor the water conductivity and perform
drains to maintain the water at optimal conductivity for peak performance.
 The auto adaptive cycle provides the longest cylinder life in combination with keeping the
tightest control and most efficient use of water during the entire cylinder life.

Steam Distribution

Steam generated by the humidifier may be introduced into the air in several different ways. The
most common method for adding the steam into the air is to mount a steam distributor tube in
a supply air duct as shown in Figure 36: Humidifier Schematic. For larger ducts or larger loads it
is also common to use a steam manifold with a single steam line connection and multiple tubes
for distributing the steam, see Figure 37: SAM-e Manifold. For introducing steam directly into a
room, humidifier mounted or remote mounted blower packs are used see Figure 38: Remote
Blower Pack.
Operation | 44