| 摘要 |
PURPOSE:To remove fouling due to action of an electrode made of carbon automatically and quickly, by running an acid liquid to perform a specified potential scanning when a measured value of a reference liquid is not valid after the measurement of a measuring liquid for a specified time. CONSTITUTION:Normally, valves 2a and 3a of a reference liquid tube 2 and an acid liquid tube 3 are closed while a valve 1a of a measuring liquid tube 1 is opened with a controller 9 and a measuring liquid runs into an electrolytic cell 5 to perform a measurement for a specified time. After a specified time passes, the valve 1a is closed while the valve 2a is opened and a reference liquid runs into the electrolytic cell 5 to measure the density thereof. When a current value recorded with a recorder 8 coincides with the density of the reference liquid, the valve 1a is opened while the valve 2a is closed to measure the measuring liquid in the same way as in the normal operation. Otherwise, the valve 1a is closed while the valve 3a opened and an acid liquid runs into the electrolytic cell 5 to fill. Thereafter, a specified potential scanning of the electrolytic cell 5 is performed to remove fouling accumulated in a working electrode 5b made of carbon. Subsequently, the valve 3a is closed while the valve 2a opened and a reference liquid runs into the electrolytic cell 5 to measure and improvements in characteristic are judged by potential scanning.
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