Automatic cuvette for determining COD - with rapid removal of hydrogen chloride by rotating inclined cuvette

摘要

A method or rapidly determining the chemical oxygen demand by increasing the surface area of the substance under test with removal of hydrogen chloride and simultaneous processing of a number of specimens (6,12, 18 or 24) comprises rotating the specimen vessels in a vertical or pref. slightly inclined position about their own axis. Pref. a number of specimens are mounted upright and slightly inclined in a circular or rectangular formation and are rotated each about its own axis. A slight vacuum may be applied to the cuvettes to reduce the vapour pressure. Heat is applied to accelerate evaporation of hydrogen chloride. Used for determining the chemical oxygen demand of water, where the potassium dichromate quantity is determined as a measure of the oxygen equivalent. By exposing a larger surface of the liquid, the hydrogen chloride is more rapidly removed and thus the process carried out more rapidly.