Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 14, 2008
Publication Date: July 1, 2008
Citation: Baker, K.D., Hughs, S.E., Chun, D.T. 2008. Use of a rotor spray system for moisture addition to cotton lint. Applied Engineering in Agriculture. 24(4):491-495. Interpretive Summary: Cotton producers and ginners are interested in adding moisture to cotton lint as it is packaged into bales after ginning in order to increase profitability. Systems which use steam to add moisture have been used for many years. Recently, systems which spray a water mist have been marketed for adding moisture to cotton lint. A concern has arisen among the cotton textile industry about the storability of cotton bales that have had moisture added. Certainly, there is a level at which the added moisture will result in microbial growth that can affect the lint color. Steam systems are limited in the amount of moisture that can be added, and color changes have not been a problem to date. The new spray systems are capable of adding many times more water than a steam system, and some problems have been noted. This research is one of several projects to generate data for which a voluntary, industry-wide standard can be forged regarding the acceptable level of moisture addition to cotton lint with spray systems. This study also reports on results from a rotor spray system rather than the alternate spray nozzle system that can be used. The rotor spray system is better for adding moisture to lint because finer droplets are produced and the spray is distributed more evenly across the width of the cotton bale.
Technical Abstract: Tests were conducted using a rotor spray system to apply moisture in the form of fine water droplets to cotton lint at the lint slide just before bale packaging. Initial cotton moisture content ranged from 5.0 to 5.5%, dry basis. Two studies were conducted, one in which bales were stored for six months and another in which bales were stored for fourteen months. In both studies, cotton quality degradation was determined after each of these storage periods. For the six month storage test, five levels of moisture addition were studied, including 6.3, 6.5, 7.0, 7.7, and 7.9 % moisture (after rewetting), in addition to bales with no additional moisture added. For the fourteen month storage test, three levels of moisture addition were studied, including 8.0, 8.4, and 10.0 % moisture (after rewetting). In both tests, no significant changes in micronaire or strength or any AFIS properties were found. Color Rd significantly decreased (color darkened) for bales at moistures above 8.0 % when stored for fourteen months, but was unchanged for other treatments. At moistures of 7.5% and greater, the color +b value decreased slightly and the decrease was statistically significant. When considering the moisture range used in this study, results are consistent with earlier studies using atomizing spray nozzles. Therefore, recommendations for using a rotor spray system for adding moisture to cotton fiber at the lint slide should be the same as those for using an atomizing spray nozzle system.