The automotive industry has many applications that can benefit from proper environmental conditioning including precise moisture control. Needs include improved coating output while reducing waste, prevention of corrosion on machined parts and improved machining accuracy. These and many other applications are all solved with desiccant dehumidification.
Brewing requires large amounts of heat, water and malted grain. Hygiene is important yet typically an inherent problem in any brewery or distillery. The growth of mold and fungus on walls, in the hops storage area and in the fermentation and yeast propagation rooms is caused by one common factor…humidity. If ambient humidity levels remain unchecked, microbes and fungus may grow in its place and disrupt the brewing process.
One of the most important parameters to be considered in the production and storage of fertilizers is the relative humidity (RH) within the production or storage area. As a rule of thumb, most fertilizers must be 40% RH or lower. If the humidity goes above 40%, the prills, being very hygroscopic, absorb moisture causing them to stick together. Another side effect of high humidity is that in contact with hydrocarbon, the ammonium nitrate becomes explosive in nature.
Candies are all manufactured with sugars or a sugar substitute and all are hygroscopic and therefore require attention to the RH% both in manufacturing/packaging and in storage. Moisture can microbiologically contaminate the ingredients or product. Chocolate bloom formed by the action of moisture on the sugar ingredients is a concern as well.
Humidity problems in the marine industry are a constant battle. Moisture causes damage during new construction, attacks vulnerable interior surfaces during sandblasting, damages engine parts and causes millions of dollars worth of damage to moisture sensitive cargo. There is also a demand that the ship’s holds are clean and dry before a new cargo is loaded.
Moisture is an operational concern in many facilities. Cold storage warehouses, product coolers and cold docks typically have large, central refrigeration systems to control the freezers and docks at their operational temperature, but often require a defrost cycle. Below 50°F a refrigeration system alone is not practical for controlling moisture and condensation. Moisture results in wet or icy floors and ceilings, frosted evaporator coils, fog, and frosted product or packaging.
Moisture causes corrosion of circuit points, condensation on microchip circuit surfaces, and improper adhesion of photoresists, all causing operational failure of semiconductor assembly. Moisture should be controlled to a maximum of 30% RH to improve quality and prevent failure.
Proper preservation is achieved through moisture control, which enables rapid deployment of the stored equipment without concern for corrosion, mold, fungus and other contaminates that may impact equipment performance upon reactivation.
Food manufacturers need to prevent condensation on surfaces, as moisture encourages the growth of microbiological organisms in the product. Many plants need to monitor and record humidity levels in food warehouses, processing plants and cold storage.
Controlling moisture in these areas provides many benefits which contribute to a healthier environment not only for the patient but for the medical staff. Trends in dew points for these facilities are dew points of 40°F to 42°F, down from past targets of 45°F to 50°F. Bacteria and viruses flourish in humid air, yet with low dew points we can maintain levels of 35% RH and lower where bacteria and viruses are not a concern.
Moisture naturally migrates through the air from a higher concentration to the lower concentration due to a difference in vapor pressure. When air is cooled it is not able to hold its moisture thus, moisture will condense on any surface that has a lower temperature than the dew point temperature of the air. Excessive moisture creates many problems with ice skating facilities including condensation on the structure leading to dripping and corrosion, puddles on ice, soft ice and fog among other things.
Low humidity environments are critical because lithium reacts with water vapor to form lithium hydroxide, hydrogen and heat. Water vapor acts as a catalyst, thus the rate at which these reactions occur depends upon both the moisture level in the atmosphere and the time that the lithium metal is exposed to moisture. The gas produced by the reaction will cause increased internal air pressure in battery cells which increases their expansion behavior. The more moisture the lower the quality, discharge capacity, performance and shelf life of batteries.
Removing moisture during facility/plant layups is critical to protecting the facility and its equipment from damage from condensation and corrosion. Reducing the amount of water vapor in the atmosphere inside a facility will limit the reaction of the water vapor with the surrounding surfaces. Applications range from entire facilities to individually applied systems on equipment from boilers, generators, turbines, ovens, etc.
Moisture is the natural enemy of preservation. Moisture results in the decay of paper, parchments and photographic film while also causing organic colors, inks, and dyes to fade. If proper measures are not taken with these often irreplaceable artifacts, which are made of organic materials including wood, leather, paper, natural fibre, bone, ivory, etc., history could be lost forever. 30%RH is a typical target for moisture control in these applications.
In conjunction with a drying oven, a desiccant dehumidifying system is required for final drying. The dehumidifier is typically applied in the final stage where very dry air is required which cannot be accomplished by heat alone without damage to the onion. Onion cold storage should be kept at a temperature of 32°F, keeping the onions dormant and free from decay, provided the onions are sound and properly cured prior to storage.
In general, a dry, cool environment results in faster processing and greater product quality. The majority of tableting operations require humidity levels between 20 and 35%RH. Proper conditions maintain product quality and production equipment reliability, improves yield, and provides safer environments.
The manufacturing of photographic film is a process which is highly sensitive to atmospheric conditions. Both temperature and humidity conditions must be closely controlled and monitored. Light sensitive photographic film consists of a flexible support, called the base, which is coated with a gelatin emulsion containing salts of silver. The film is laminated from several different emulsions and must be dried between each application. Due to the fact that film is sensitive to temperature, desiccant dehumidification with a cool dry discharge provides the solution.
Low humidity provides the ideal environment for the powder particles to sustain their charge prior to impact with the surface to be coated resulting in a more complete and even coat. Because most powders are hygroscopic, humidity control will reduce agglomerates forming on the walls of the recovery duct, filters and tubing.
As with other layup situations, moisture is the enemy. Moisture creates condensation and facilitates corrosion on the surfaces of critical components. Removing the key ingredient for condensation and corrosion via dehumidification improves system reliability, reduces expensive maintenance and repair, extends the life of the system and can increase system output when coupled with other maintenance techniques.
When paper is exposed to temperatures below the ambient temperature, the paper begins to absorb moisture from the surrounding air. This can be the case with storage facilities, which often have limited environmental conditioning, or with protected papers opened for processing. Moisture causes expansion, waviness and curling of paper, resulting in quality issues during printing. Moisture can also delay the drying of inks, leading to smudging and set off.
Traditional air conditioners overcool the airflow in order to lower the humidity. In doing this, the lower air temperature becomes unpleasantly cold. A balance can be achieved with a “packaged” system that applies two technologies: Refrigeration and Desiccant Dehumidification. Desiccant technology is also important in high humidity climates for make-up air due to kitchen exhaust.
Most seed-bearing plants produce seeds that can be dried to a low moisture content and then frozen. Drying, sealing and freezing will often lead to at least a 100-fold increase in seed storage life. Improper drying and storage conditions in handling seeds can have an adverse effect on the seeds life, causing loss in viability, discoloration, toxin production and growth of fungus.
The gelatin capsule is very sensitive to airflow, air temperature and moisture content. If the gelatin sets too rapidly it will become brittle, while too high of an air velocity will disturb the consistent thickness of the gelatin ribbon being formed. If the air temperature and humidity are too high, or the air velocity is too low, the gelatin will not solidify into a ribbon. Thus, the need for constant control of the air being introduced is critical in the process.
When material is stored in a silo there is usually a “dead space” or open area at the top which is left open for air circulation. This empty space can create problems because the variation of temperatures outside the silo will result in condensation in this space. This condensation forms on the walls and can lead to corrosion of the silo itself, caking and agglomeration of hygroscopic material stored inside or microbial activity leading to the spoilage or contamination of the material being stored.
When moisture in the air condenses onto cold pipes, valves, and pumps, a number of destructive effects can occur. High humidity resulting from a damp environment can cause corrosion of metal, deterioration of paint, and failure of electrical components. Sanitation also becomes a concern when a moist location acts as a breeding ground for the development of bacteria, fungus and molds.
Wood products are highly impacted by moisture. Many wood products are stored in improper conditions, resulting in poorly finished product quality and drop or loss from expensive wood trims, floors, etc. Manufacturing of wood products at lower moisture levels produces a precise and repeatable process until assembly and/or finishing. Adhesive application and curing is also improved in many cases.
The drying of yeast is an intricate process, requiring cold dry air to produce quality yeast without destroying the micro-organism. The quality of the air required for drying yeast must be controlled at a temperature of 12 to -18°F and a humidity level of 10 to 14 grains/1b of air. The ideal condition for the manufacturing of yeasts involves low temperature drying. Although elevated temperatures can result in faster drying times, there is a significant risk to product quality.