LIQUID QUALITY-EVALUATING APPARATUS FOR DETERMINING BOILING OR VAPOUR LOCK POINT OF A LIQUID SUCH AS BRAKE FLUID

摘要

A liquid quality-evaluating apparatus for liquids whose boiling point or vapour lock point vary by deterioration includes a heating vessel made of heat conductive and electrically conductive material and adapted to hold a brake fluid whose quality is to be determined. The heating vessel has its opening closed by an electrically insulating cover and the wall of the heating vessel near the bottom is fitted with a nozzle acting as a syphon. The cover is fitted with a hollow cylindrical electrode so disposed as slightly to dip into a brake fluid received in the vessel. A heat-responsive resistance clement for detecting the temperature of the brake fluid is received in the hollow cylindrical electrode. A heater is provided below the heating vessel to heat the brake fluid received therein. A current cutoff-detecting circu? is electrically connected between the heating vessel and the hollow cylindrical electrode. A liquid temperature-indicating circuit for displaying the temperature of the brake fluid is connected to the heat-responsive resistance element. A liquid temperature-indicating pointer used with the liquid temperatureindicating circuit is locked by an output signal from the current cutoff-detecting circuit which is actuated when the level of the brake fluid falls when the brake fluid boils.