A User-build System for Automated Monitoring 

 and Controlling of CA Apple Storages 



William J. Bramlage 



Department of Plant & Soil Sciences, University of Massachusetts 



The Orsat gas analyzer is used almost exclusively in 

 New England to determine the concentration of Oj and 

 COj in controlled atmosphere storages. Adjustments of 

 the Oj and the COj levels are then performed manually by 

 the storage operator. Use of the Orsat is subject to 

 considerable operation error. It also is time-consuming, 

 resulting in atmosphere sampling no more often than once 

 a day in most storages, which in turn can result in signifi- 

 cant atmosphere fluctuations, or in problems going unno- 

 ticed or uncontrolled for some time. Probably for these 

 reasons, CA operators tend to be very conservative in their 

 desired O^ and CO^ levels, thus forfeiting some of the 

 potential benefits to the fruit from the CA atmosphere. 



To try to improve on CA management in New Eng- 

 land we have developed a demonstration system at the 

 Horticultural Research Center, Belchertown, that auto- 

 mates the CA control procedure. This idea is not new. 

 Numerous automatic control systems have been devel- 

 oped in other areas, and some excellent systems are 

 commercially available. 



Our approach was to try to develop a system at 

 minimal cost to the storage operator, since many New 

 England storages are small and the operators are short on 

 investment capital. It is a system using off-the-shelf com- 

 ponents, in which the storage operator is involved from the 

 outset in developing a system to meet his or her specific 

 conditions and needs. 



Our system was developed by Katrin Kaminsky, as 

 part of her M.S. thesis, in cooperation with personnel in the 

 Department of Food Engineering who have expertise and 

 experience in control systems and computer technology. 

 The project was funded by a grant from the Massachusetts 

 Society for Promoting Agriculture, with supplemental 

 funding from the Massachusetts Agricultural Experiment 

 Station. 



The system is designed as a working demonstration of 

 automated sampling and control of a CA atmosphere. It is 

 in ongoing use at the Horticultural Research Center. To 

 provide storage operators with ready access to information 

 about the system, a University of Massachusetts Coopera- 

 tive Extension Publication has been prepared and is now 

 available. The publication provides a step-by-step descrip- 

 tion of the system we have developed, and a complete 

 listing of supplies and costs that were involved. 



The publication, entitled, "A User-built System for 

 Automated Monitoring and Controlling of CA Apple 

 Storages," publication C-197, is available from William 

 Bramlage or Wesley Autio, Department of Plant & Soil 

 Sciences, Bowditch Hall, University of Massachusetts, 

 Amherst, MA 01003. We sincerely hope that CA opera- 

 tors will obtain a copy and carefully evaluate the applica- 

 tion of this system to their operation. We hope that many 

 operators will take the appropriate steps to upgrade their 

 storage operations with the technology that is now in hand. 



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