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 Click here to download and print this article  Adobe Acrobat Reader is required to Download and Print this article A Fine Mist: Dry Winter Air Sparks Humidity Control Debate by Del Williams Beyond traditional humidification, a new method improves coverage and responsiveness while reducing water use, over-wetness, maintenance and installation cost Print facility managers know the problem. If they don't control the facility's relative humidity, paper and print quality as well as production suffer. The problem worsens each winter when cold weather reduces the moisture in the air. To assure consistent quality and production, print experts are turning from traditional humidification techniques to a new method that dramatically improves humidification coverage and responsiveness while reducing water use, over-wetness, maintenance and installation cost. Since paper products are porous, they can quickly gain or lose moisture from the surrounding air in the print or storage process. Low moisture is a particular danger in winter when relative humidity can go as low as 15%. When relative humidity falls below 50 percent, paper shrinks, curls and loses dimensional stability. This can cause paper to stick, mis-feed and mis-align colors. It can also cause tears in web-based newspaper printing, forcing costly downtime. To prevent waste and downtime, print experts must keep the relative humidity of air around print production and storage between 50 and 60 percent. While achieving this once in a while may be easy, doing so thoroughly, consistently and efficiently can be difficult. The challenge is that humidification coverage must be complete, uniform, and responsive to changing moisture levels in the air. It must keep all paper from getting too dry and too wet. Water vapor collecting in the wrong pattern, in fact, can "fall out" to create areas of wetness while other areas may remain too dry. In an age of tight budgets and rising commodity prices, thought also needs to be given to reducing water and energy use, and maintenance and installation cost. In search of a solution, at least one humidification innovator named Fogco aims to achieve complete humidification of facility areas up to 10,000 cubic feet without "fallout" or wetness. But first here's a look at the status quo of industrial humidification. A number of traditional misting systems add moisture to the air in industrial applications. While these offer benefits, they've been limited by drawbacks. Among high-pressure fog systems, which create and distribute tiny water droplets based on the humidity level needed in an area, static line systems and vertical fan systems have been common choices. With static line systems, which mount and align tubes and nozzles to deliver mist, uneven humidification distribution can be a problem. Moisture may not completely or uniformly evaporate into the surrounding air, especially in facilities with low ceilings. Nozzles which spray a certain distance and direction can create areas of too much moisture or wetness under a nozzle. Other areas farther from mist-spraying nozzles may receive too little humidification. With no airstream to spread humidification beyond the nozzle spray areas, it can be difficult to provide complete, uniform coverage and it can take longer to reach desired humidification levels. Water moisture "fall out" can damage paper products and increase water use -- especially in areas with low ceilings -- while labor-intensive tubing alignment and mounting can increase installation and maintenance cost. A vertical fan humidification system adds an airstream to aid air moisture distribution, but a stationary airstream typically covers just a narrow band 25-degrees wide. Like a flashlight's beam, this leaves many areas outside its focus. Thus humidification may be relatively slow to diffuse, with pockets of relative dryness remaining. Adding fan oscillation can distribute mist over a wider area, but still leave areas with less humidification while the airflow is pointed elsewhere. Turbulence is also created when airstreams cross, leading to increased "fallout" and water use with diminished humidification. Air and water humidification systems, combining low-pressure water and high-pressure air to atomize water droplets, also have drawbacks for industrial use. These include high upfront costs for nozzles that combine air and water, expensive air compressors, and expensive separate lines for air and water. The cost of maintaining dual air-water systems typically runs high as well. For print experts seeking to prevent production or quality issues such as dry air-caused shrinking, curling and loss of dimensional stability especially in winter, at least one company, Fogco, believes they have a solution that eliminates the drawbacks of traditional industrial humidification. Developed with input from industrial customers, an integrated climate control system called the "Revolution" by Fogco (www.fogco.com) aims to achieve complete humidification of facility areas up to 10,000 cubic feet without "fallout" or wetness. If, like a flashlight, traditional static lines or vertical fans emit narrow "beams" of humidification, then the Revolution acts like a floodlight, bathing a whole area with humidification. What's unique about the Fogco technology is how it achieves continuous, even, 360-degree humidification coverage from ceiling heights as low as 8'. Hung like a simple ceiling fan, it broadcasts a fine "invisible mist" outward in a horizontal circle along a stream of air. By integrating the horizontal airstream with the fog, its micron-size water droplets stay suspended much farther and longer than traditional systems. This provides better, more even distribution of humidification, more complete evaporation, and virtually no "fallout." "Customers like using a high-pressure humidity system like the Revolution, especially at low ceiling heights," said Hal Wilson, President of Air & Water Systems, a leader in humidification system design and installation. "It's the preferred system because it can put out a lot of moisture without disturbing the work environment." As the industry's first 360-degree vented mist system for humidification, the Revolution provides up to five times the coverage of static line systems with less water, maintenance and installation cost. With more rapid, even humidification distribution, paper can stay closer to an ideal 55% relative humidity. This enhances print production speed and quality, along with storage. Compared to air and water humidification systems, the 360-degree vented mist system offers advantages as well. "The Revolution works for many different applications and, unlike compressed air systems, makes little noise while using a lot less power," said Wilson. For instance, the system uses just 1.8 amps of 120V/1 phase power for 100 lbs per/hour output, compared to a typical compressed air system using a 6-Hp industrial compressor for similar output. In a time of budget constraints where print experts need to minimize cost, the Revolution's simplified installation can save resources too. Since it hangs like a ceiling fan, it reduces installation and maintenance cost. Its set up eliminates the need to work around poles, perimeters, columns, and changes in floor elevation, reducing labor cost and cutting installation time about 90% compared to static line system installation. "Along with ease of installation and low maintenance, the Revolution provides money saving options with improved results," concludes Wilson. The Fogco Revolution can be mounted from any overhead structure, used indoor or out, and comes with an outdoor rated fan and powder coated enclosure. The mist system for humidification is portable when mounted from a custom stand. The system is designed to operate with any Fogco pulley-driven or direct-drive 1,000-psi fog pump, and is customizable by choice of appropriate Fogco nozzles. For more info, call 480-507-6478; fax 480-838-2232; email info@fogco.com; or write to Fogco Systems, Inc., 600 South 56th Street, Suite #9, Chandler, AZ 85226. Del Williams is a technical writer based in Torrance, California |
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