L'étude de l'encrassement d'un échangeur de chaleur à plaques (modèle VICARB Mots clés: Encrassement -Nettoyage -Echangeur de chaleur à plaques -Desserts chocolatés. Summary Fouling and cleaning study of a plate heat exchanger used for chocolated desserts processing The study of heat exchanger surfaces fouled by cre am based desserts preparation was carried out on a VI CA RB V7 type exchanger. Three trials were made. The fouling evolution was measured on line using the method described by

more »

... Eand CORRIEU F. RENÉ el al. (1979). The exchanger was opened each time and the wet weight of deposits adhering to the plates was measured in arder to establish inside repartition of deposits along the temperature profile. One plate out of two was removed and the deposit was collected and analysed (protein, minerais, fat and carbohydrates content). Then the exchanger was set up with cleaned plates in place of removed ones. Three cleaning tests were made with different alkaline products. Better cleaning, as observed after exchanger opening was obtained when specifie cleaning products are used. Two trials were then performed on an industrial exchanger in arder to quantify cleaning efficiency of these products. Results were compared with those obtained during UHT treatment of milk. Similarity in composition of deposits and mass repartition is presented and discussed. The difficulty of removing soils from surfaces with cleaning in place was observed once again. Compounds like starch, cocoa and chocolate in the mixture certainly interact between them, sa interpretative models developed for milk fouling need ta be used carefully in this case.