The Humidity Control Debate by ProQuest

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One system on the market achieves continuous, even, 360-degree humidification coverage from ceiling heights as low as 8 feet. Hung like a 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 water droplets stay suspended farther and longer. This provides better, more even distribution of humidification, more complete evaporation, and virtually no "fallout."

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                                                            FEATURE
                                                                                           The Humidity Control Debate
                                                                      By Del Williams                                        line systems and vertical fan systems have been      Air and water humidification systems, combin-
                                                                      Beyond traditional humidification, a new method        common choices.                                      ing low-pressure water and high-pressure air to
                                                                      improves coverage and responsiveness while                                                                  atomize water droplets, also have drawbacks for
                                                                      reducing water use, over-wetness, maintenance,         With static line systems, which mount and align      industrial use. These include high upfront costs
                                                                      and installation costs.                                tubes and nozzles to deliver mist, uneven humid-     for nozzles that combine air and water, expensive
                                                                                                                             ification distribution can be a problem. Moisture    air compressors, and expensive separate lines for
                                                                      Print facility managers know the problem. If           may not completely or uniformly evaporate into       air and water. The cost of maintaining dual air-
                                                                      they don’t control the facility’s relative humidity,   the surrounding air, especially in facilities with   water systems typically runs high as well.
                                                                      paper and print quality, as well as production,        low ceilings. Nozzles which spray a certain dis-
                                                                      suffer. The problem worsens when cold weather          tance and direction can create areas of too much     New Techniques
                                                                      reduces the moisture in the air.                       moisture or wetness under a nozzle. Other areas      For print experts seeking to prevent production
                                                                                                                             farther from mist-spraying nozzles may receive       or quality issues such as dry air-caused shrinking,
                                                                      To assure consistent quality and production, print     too little humidification.                           curling and loss of dimensional stability, there is
                                                                      experts are turning from traditional humidifica-                                                            another option.
                                                                      tion techniques to a new method that improves          With no airstream to spread humidification
                                                                      humidification coverage and responsiveness             beyond the nozzle spray areas, it can be difficult   If, like a flashlight, traditional static lines or verti-
                                                                      while reducing water use, over-wetness, mainte-        to provide complete, uniform coverage and it can     cal fans emit narrow “beams” of humidification,
                                                                      nance and installation costs.                          take longer to reach desired humidification lev-     then what is needed is a floodlight-type system,
                                                                                                                             els. Water moisture “fall out” can damage paper      bathing a whole area with humidification.
                                                                      A Print Problem
                                                                      Since paper products are porous,                                                                                 One system on the market achieves continu-
                                                                      they can quickly gain or lose mois-                                                                              ous, even, 360-degree humidification cover-
                                                                      ture from the surrounding air in                                                                                 age from ceiling heights as low as 8 feet.
                                                                      the print or storage process. Low                                                                                Hung like a ceiling fan, it broadcasts a fine
                                                                      moisture is a particular danger                                                                                  invisible mist outward in a horizontal circle
                                                                      in winter when relative humidity                                                                                 along a stream of air. By integrating the hori-
                                                                      can go as low as 15 percent. When                                                                                zontal airstream with the fog, its water drop-
                                                                      relative humidity falls below 50                                                                                 lets stay suspended farther and longer. This
                                                                      percent, paper shrinks, curls and                                                                                provides better, more even distribution of
                                                                      loses dimensional stability. This can                                                                            humidification, more complete evaporation,
                                                                      cause paper to stick, mis-feed and                                                                               and virtually no “fallout.”
                                                                      mis-align colors. It can also cause
                                                                      tears in web-based newspaper                                                                                     “Customers like using a high-pressure
                                                                      printing, forcing costly downtime.
								
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