AIR
HANDLING UNIT HUMIDIFIER
humidifiers add moisture to warm, circulated air in order
to protect furnishings and reduce static electricity. They
use deionized, demineralized, softened, or untreated water.
There are several basic types of industrial humidifiers. Conventional
steam humidifiers use an electrical or gas-fired heater to
boil water and release steam into the air. Direct or live
steam humidifiers inject steam directly into an air handling
system or ductwork. By contrast, liquid-to-steam systems transfer
energy from a hot liquid, usually water, through a heat exchanger
inside a water-filled chamber. Steam-to-steam systems that
use a heat exchanger inside a water-filled chamber are also
available. Unlike other types of industrial humidifiers, ultrasonic
devices vibrate a piezoelectric transducer at a very high
frequency to create tiny water droplets instead of steam.
In some systems, specialized nozzles are used to discharge
a mist of atomized water and compressed air.
Specifications for industrial humidifiers include primary
voltage, power demand, output capacity, steam pressure,
rated input, and control tolerance. For non-ultrasonic systems,
the primary voltage is the voltage supplied to the heater
or heat exchanger. Power demand, the rated power of the
humidifier, is typically expressed in kilowatts (kW). Output
capacity is the amount of steam or vapor that industrial
humidifiers can generate in a fixed amount of time. Steam
pressure is the pressure supplied for both direct duct injection
and indirect heating. Measured in British thermal units
(BTUs), rated input applies only to systems that use gas-fired
heaters. For all types of industrial humidifiers, control
tolerance is the percentage of control around a given set
point. For example, if a system is set to 60% humidification,
then a control tolerance of 5% allows for positive adjustments
to 65% and negative adjustments to 55%.
Industrial humidifiers vary in terms of features and mounting
styles. Some devices include built-in diagnostics, an integral
control panel, or remote communications. Others are self-contained
and include water demineralization or cleaning features.
Modular systems can be linked together in order to increase
output capacity. Industrial humidifiers with temperature
sensors and proportional controls are also available. In
terms of mounting styles, industrial humidifiers can be
mounted on ceilings or walls, or in air handling systems.
Free standing and portable devices are commonly available.
Remote systems use steam piped in from another location.
Industrial humidifiers are used in the heating, ventilation
and air conditioning (HVAC) systems of office buildings,
and in a variety of commercial and industrial applications.
For example, printing plants use industrial humidifiers
to reduce static electricity in the ink wells of large,
high-speed web presses. Plastic manufacturers also use industrial
humidifiers, but to reduce the buildup of dust on rollers
and machinery. Industrial humidifiers are used widely in
computer rooms, laboratories, and semiconductor manufacturing
facilities.
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