The voltage in the terminal area of standard resistance and this standard resistance and the aforementioned electrode which are in series connected to the volume resistivity meter and the liquid purity monitor

摘要

PROBLEM TO BE SOLVED: To provide a purity-monitoring method that can safely measure even a flammable liquid such as IPA (isopropylene alcohol) containing water and at the same time can continuously and accurately measure even a liquid for causing polarization. ;SOLUTION: A reference resistor Rs that is connected in series with electrodes 6 and an amplifier 7 for converting voltage at a connection part P between the reference resistor Rs and the electrode from a high impedance Vxh to a low impedance Vxl and for outputting it are provided at a sensor part 2 for measuring the resistivity of a liquid that exists between the electrodes 6. In this case, the resistivity of the liquid is measured according to the ratio of the output voltage Vxl of the amplifier 7 to a reference voltage Vs being applied to the sensor part 2, and the purity of the liquid is monitored based on the resistivity.;COPYRIGHT: (C)1999,JPO