Detector of liq. contamination - measures rate of cooling gradient of sensor (SW 5.12.77)

摘要

A sensor at a relatively high temp. is immersed into a sample of the tested liquid. It is cooled down to a first temp. at which the presence of a contamination begins to have an effect on the liquid cooling. The rate is measured at which the sensor cools down from the first temp. to a second, lower temp. The liquid is typically an annealing, quenching or hardening oil, for which the temp. range appropriate is 500 deg.C to 200 deg.C. The sensor is pref. in the form of a long bolt of stainless steel. Heating is provided by an electrical resistance oven.