Abstract
In order to find the basis of the plan of the heat exchanger of a digester, the writer studied the quantity of the digesting heat by calculation, from which he deduced the steam quantity of digestion. He found the quantity of the heat which was transmitted to the digested solution from the heating surface of the heat exchanger. Relying on the basis of the calculation, he explained the method to know the area of heat transmission of the heat exchanger. In the end, he explained by real examples the changes of the quantity of sulphur in the digester, and referred to the gas cooler.
