Apparatus for measuring impurities in super-pure water without exposure

Abstract

A measuring apparatus for measuring the number and size of impurities such as dust and bacteria in super-pure water includes a sealed container; a sample supply line which sealingly interconnects a source of super-pure water with the sealed container and supplies a sample mixture of super-pure water and electrolyte to the sealed container; an overflow pipe which sealingly connects with the side of the sealed container; a negative electrode which extends into the sample mixture in the sealed container; a hollow sensor which extends into the sample mixture in the sealed container, the hollow sensor containing a positive electrode surrounded by electrolyte and having a small hole at its lower end; and a detecting circuit connected to said negative and positive electrodes for supplying a certain DC current therebetween and detecting voltage pulses caused by impurities passing through the small hole into the hollow sensor.