GUM CONTENTS IN FUELS BY JET EVAPORATION

Existent Gum is the evaporation residue of aviation fuels and other volatile distillates without any further treatment or discarded washings with heptanes. A measured quantity of fuel is evaporated under controlled conditions of temperature and flow of air or steam. For aviation gasoline and aviation turbine fuel, the resulting residue is weighed and reported as milligrams per 100 ml. For motor gasoline, the residue is weighed before and after extracting with heptanes and the results reported as milligrams per 100 ml.