systems remove moisture from the air without cooling it, allowing for the separate
control of temperature and humidity and saving costly energy. Gas desiccant systems
can remove more than twice as much moisture from the air as a refrigeration system.
This is because they generally require less than half the air volume required
by conventional electric cooling systems to control humidity. Natural gas desiccant
systems also complement conventional gas or electric air conditioning systems
because drier air is easier to cool. This allows the cooling equipment to operate
more efficiently and the system's air handling equipment to be downsized.
mold coolant temperature must be maintained for optimum results in the plastic
injection molding process. Yet rapid cooling of the mold causes water vapor in
the surrounding air to condense on the tool surfaces, which can lead to corrosion
in addition to watermarks and cracks on the finished part. If coolant temperatures
are raised to avoid condensation, cycle times become slower, production decreases,
and resin processing parameters change.
provides year-round control and increased productivity by preventing condensation,
eliminating slippery floors, improving refrigeration efficiency plus reducing
the cooling load and defrost cycles. Controlling the environment results in lower
operating costs and an improved bottom line for most facilities.
moisture from the air, chilled water can be used instead of room temperature water
to significantly decrease machine cycle time. As a result, parts cool faster,
molding equipment lasts longer, and maintenance and retooling costs are reduced.
desiccant dryers offer the following benefits:
- Removes High
- Reduces Corrosion
through the Elimination of Condensation
- Safer Working
- Lowers Energy
and Maintenance Costs
- Fewer Molding
- Produces Faster
- Reduces Scrap
- Lower Coolant
Temperatures Made Possible
Desiccant systems can be used in three ways:
1. Spot dehumidifiers
deliver dry air directly over the surface of the mold when it opens. This method
uses a small dehumidifier and requires ductwork to bring the dehumidified air
to the mold cavity.
shrouding involves construction of a small chamber to encase the molding machine
and limit the infiltration of moist air to the machine.
conditioning eliminates distribution ductwork. However, with a larger space to
condition, the unit must be sized to compensate for room openings, people and
the presence of other types of equipment.
Any manufacturing or processing function that is sensitive to humidity,
temperature or microorganisms is a natural application for a dehumidification
- Plastic injection
- Food process
- Clean rooms
encapsulation and packaging
films and papers
- Glass lamination
- Heat sensitive
Gas-fired dehumidification uses either liquid or solid desiccants to
remove water vapor from the air.
Liquid desiccant material is a highly stable, nontoxic solution that
attracts moisture. As the air to be dehumidified comes into contact with the liquid
desiccant, the moisture is absorbed into the solution. The amount of moisture
taken out of the air is directly related to the concentration and temperature
of the solution. The solution is then boiled off, and the moisture is removed
and released into the atmosphere. This restores the solution's ability to reabsorb
moisture and begin the cycle again.
Solid desiccants are used in a wheel-type system that resembles a round
honeycomb. The holes serve as air channels, each coated with solid desiccant material.
Air passes through the holes allowing the desiccant to absorb any moisture in
the channels. As the desiccants continue to pick up moisture, their ability to
absorb at 100 percent is diminished. This is where natural gas is used. While
slowly rotating, 25 percent of the desiccant wheel is dried using a natural gas
heat source. The heat evaporates the moisture, releasing it into the atmosphere,
while the desiccants regain their maximum absorption ability.