operation. 



A detailed assessment of the operation of this system versus that of an 

 Orsat-monitored system will be published later. However, an obvious benefit 

 was the time-saving achieved by automatic monitoring of atmospheric conditions 

 in the CA rooms. This savings was especially appreciated during the initial 

 pull-down period. At this time, the hourly program was deactivated and a 

 continuous O2 reading was taken for the room being flushed with liquid-N2. 

 This allowed the operators to watch the changes in O2 level as the liquid-N2 

 was metered into the room. 



Total cost of the equipment was approximately $8500. However, the 

 dewpoint indicator cost $1300 and was included in our system for research 

 purposes. Likewise, our system has greater control capability built into it 

 than a commercial operator might desire, since we may wish to completely 

 automate controls for research purposes. 



The establishment of this system has created the opportunity for us to 

 demonstrate the feasibility and advantages of automatic CA operation. This is 

 neither a new idea nor new technology. Similar — and often more sophisticated — 

 systems are in commercial use in many parts of the world. Our objective in 

 this project is to lead the way in upgrading New England storage operations to 

 the level of many of the area's competitors, and through better storage 

 operation to provide a higher quality apple for the market. 



***** 



PCMOLOGICAL PARAGRAPH 



Use of Liquid-N2 for O2 Pulldown in CA Storages 



William J. Bramlage 



Department of Plant and Soil Sciences 



University of Massachusetts 



During the past two years a number of New England CA storage operators 

 have used liquid-N2 for O2 pulldown. At the Horticultural Research Center, 

 Belchertown, we have used this system and have been very pleased with the 

 results (Proc. Mass. Fruit Growers' Assoc. 92:102-105). Dr. James A. Bartsch 

 of the Department of Agricultural Engineering, Cornell University, recently 

 published a factsheet entitled, "Creating a Low Oxygen Atmosphere with Liquid 

 Nitrogen." This information should be of interest and value to anyone using 

 this system or considering use of it. The factsheet "Agricultural Engineering 

 Facts, EF-9" can be obtained from William J. Bramlage, Department of Plant and 

 Soil Sciences, French Hall, University of Massachusetts, Amherst, MA 01003. 



***** 



