ISHS Acta Horticulturae 116: Symposium on Postharvest Handling of Vegetables
A FLEXIBLE THERMO-COMPENSATION UNIT FOR MARCELLIN-TYPE GAS EXCHANGER-EQUIPPED RIGID STRUCTURED-C.A. ROOMS |
| Authors: | A. Lanson, A. Lanson, M. Baril, C. Phan |
| Abstract:
The invention by MARCELLIN (1, 4) of a selectively permeable plastic membrane-bound gas exchanger, for the realization of controlled atmospheres in fruit storage rooms, has been a landmark in the technology of fresh produces-storage. The gas exchanger proposed, and built, by MARCELLIN is a very simple unit requiring very little energy and practically no maintenance to function. For this reason, it is certainly destined to be -if not the- at least the most prominent C.A.-realizing system of the future. However, in order to have such a unit function properly, some basic principles of physics must be respected. As the whole concept is based on a static diffusion exchange of various gases through the plastic membrane, one must pay attention, not only to the temperatures and the concentrations of the gases, but also to the pressure of the gaseous mixture inside the room-exchanger continuum. The main cause of pressure variation is the rythm of the refrigeration system. And, in the Canadian context, one must add to this the frequent very sharp variations in the atmospheric pressure, and, during winter, the variations of the climatic conditions, all of which will influence the temperature, thence the shape of the rigid structure of the storage room. All these factors have rendered the application in Canada of Marcellin`s technique, which otherwise has proved to be very successful on the laboratory scale (2, 3), somewhat inadequate, even hasardous on the industrial scale. Marcellin's ideas have interested a group of farmers in Quebec who have created the company "Atmolysair Limitée" in order to develop exchangers based on Marcellin`s principles. Not only have they designed a new type of exchanger, but they have also, quite incidentally, developped an extensionbag which proved to be extremely helpful in maintaining the internal pressure, thus allowing the membrane-bound exchanger to function properly. | |
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