Abstract
In our previous papers, it was shown that the results of foundamental and practical experiment on the scale-prevention in the way of the addition of crystal seeds had been investigated. This new repot is concerned with the relations between the condition of evaporation and properties of the seed itself, and five experiments were carried out with the following results. Exp. I: the effect of suspended amounts of seeds-the results showed that the amounts of calcium sulfate crystal were adequate to 20g per liter in brine for the pratical use. Exp. 2: about the size of crystals-the smaller is the more eminent, and then the crystals made by crushing large one were also usable for seed. Exp. 3: the influence of dihydrate in anhydrite-it was found that the contents of dihydrate might be permitted up to 20% in weight. Exp. 4: the effect of temperature of the mo ther liquor and water of crystalization-the transition point was influenced by the seed, and in the temperature range from 90 to 65°C, hemihydrate one was effective relatively. But after long running, the evaporation was disturbed with the scale formation. Exp. 5: the effect of velocity of liquid circulated in heating tube-the quantities of adhered scale increased inversely to the velocity of the liquid flow and as the result of this examination, good data were obtained in the case of 0.25m/sec.
