Industrial 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.