Apparatus for measuring impurities in ultrapure water

Claim 1

In an electrical pulse apparatus for measuring impurities in ultrapure water which includes a container for the ultrapure water whose impurities are to be measured, a hollow detector which has a portion extending into said container so as to be surrounded by said ultrapure water, said portion of said hollow detector having a small hole therein to enable ultrapure water in said container to pass into said hollow detector, a supply tank for a liquid electrolyte, a first conduit system connected between said supply tank and said hollow detector for delivering said liquid electrolyte from said supply tank to said hollow detector, a second conduit system connected to said hollow detector to remove liquid therein, a first electrode positioned in said hollow detector, a second electrode extending into said container outside said hollow detector so as to dip into the ultrapure water therein, and electrical means connected to said first and second electrodes to cause a current to flow therebetween through said ultrapure water in said container and the liquid in said hollow detector and to detect voltage pulses produced by impurities passing through said small hole in said hollow detector, the improvement wherein a deaeration device is connected to said first conduit system to deaerate the electrolyte passing through said first conduit system such that bubbles formed by electrolysis at said first and second electrodes will be redissolved, thus increasing the speed and sensitivity of measurement and reducing the current needed for measurement, said deaeration device comprising a chamber, a vacuum pump connected to said chamber and a tube extending through said chamber, said tube being connected into said first conduit system, said tube being made of a synthetic resin which is pervious to gases but not liquids.