Abstract: An electrode assembly for a conductivity meter or resistivity meter includes: an electrode main body; a test liquid intake flow path passing through the electrode main body; a pair of voltage electrodes which is respectively provided so that surfaces thereof are exposed to opposing inner wall surfaces forming the test liquid intake flow path; and a pair of current electrodes which is respectively provided so that surfaces thereof are exposed to each of the inner wall surfaces, and in this configuration, each of the pair of current electrodes contains a carbon-based material, and each of the surfaces of the pair of current electrodes exposed to the inner wall surfaces is in a strip shape.

Abstract: In order to avoid an electrode from disturbing a flow of a fluid in a flow channel in case that the electrode of an electric conductivity meter is arranged in the flow channel, the electric conductivity meter comprises two tubular electrodes inside of each of which respectively formed is an inner flow channel where the fluid flows, and an electrode holder that communicates each of the inner flow channels of the two electrodes and that holds the two electrodes. The electrode holder holds the two electrodes by making an engagement with each outer peripheral surface of mutually facing axial direction end parts of the two electrodes.

Abstract: An electrode assembly for a conductivity meter or resistivity meter includes: an electrode main body; a test liquid intake flow path passing through the electrode main body; a pair of voltage electrodes which is respectively provided so that surfaces thereof are exposed to opposing inner wall surfaces forming the test liquid intake flow path; and a pair of current electrodes which is respectively provided so that surfaces thereof are exposed to each of the inner wall surfaces, and in this configuration, each of the pair of current electrodes contains a carbon-based material, and each of the surfaces of the pair of current electrodes exposed to the inner wall surfaces is in a strip shape.

Abstract: The present invention is one that makes it possible to continuously measure the resistivity of a liquid sample with accuracy as well as preventing the deterioration of the liquid sample associated with measurement, such as change in quality, and relates to a resistivity-measuring circuit C that measures the resistivity in order to sense the deterioration of the liquid sample. The resistivity-measuring circuit C is one that calculates the resistivity of the liquid sample by detecting voltage generated between an outer electrode and an inner electrode, and between the outer electrode and the inner electrode, applies square wave AC voltage having an amplitude of 1 V to 42 V and a frequency of 0.5 Hz to 30 Hz.

Abstract: In order to avoid an electrode from disturbing a flow of a fluid in a flow channel in case that the electrode of an electric conductivity meter is arranged in the flow channel, the electric conductivity meter comprises two tubular electrodes inside of each of which respectively formed is an inner flow channel where the fluid flows, and an electrode holder that communicates each of the inner flow channels of the two electrodes and that holds the two electrodes. The electrode holder holds the two electrodes by making an engagement with each outer peripheral surface of mutually facing axial direction end parts of the two electrodes.

Abstract: In order to improve measurement accuracy by accurately calibrating sensitivity of a dissolved oxygen meter without impairing easiness in calibration, the present invention includes a dissolved oxygen measuring device that includes a cell to be loaded with a sample solution, and a dissolved oxygen meter that is attached to the cell and measures an oxygen concentration in the sample solution; and a mode switching mechanism to switch between a measurement mode, in which a sensor surface of the dissolved oxygen meter is substantially in contact with the sample solution in the cell, and a calibration mode, in which the sensor surface is substantially not in contact with the sample solution in the cell, by feeding air into the cell through a feed port disposed on the cell, and by discharging part of the sample solution through a discharge port disposed on the cell.

Abstract: A measuring device comprises a guard electrode that is arranged around a cathode, reduces oxygen that is not from an oxygen permeable membrane, and inhibits the oxygen from reaching the cathode. The guard electrode is electrically connected to an anode through a resistor having a prescribed resistance.

Abstract: In order to improve measurement accuracy by accurately calibrating sensitivity of a dissolved oxygen meter without impairing easiness in calibration, the present invention includes a dissolved oxygen measuring device that includes a cell to be loaded with a sample solution, and a dissolved oxygen meter that is attached to the cell and measures an oxygen concentration in the sample solution; and a mode switching mechanism to switch between a measurement mode, in which a sensor surface of the dissolved oxygen meter is substantially in contact with the sample solution in the cell, and a calibration mode, in which the sensor surface is substantially not in contact with the sample solution in the cell, by feeding air into the cell through a feed port disposed on the cell, and by discharging part of the sample solution through a discharge port disposed on the cell.

Abstract: The present invention is one that makes it possible to continuously measure the resistivity of a liquid sample with accuracy as well as preventing the deterioration of the liquid sample associated with measurement, such as change in quality, and relates to a resistivity-measuring circuit C that measures the resistivity in order to sense the deterioration of the liquid sample. The resistivity-measuring circuit C is one that calculates the resistivity of the liquid sample by detecting voltage generated between an outer electrode and an inner electrode, and between the outer electrode and the inner electrode, applies square wave AC voltage having an amplitude of 1 V to 42 V and a frequency of 0.5 Hz to 30 Hz.

Abstract: The present invention is intended to provide a turbidimeter having a simple and sturdy structure which is hard to break and exhibits excellent long-term stability by reducing a number of sealing positions, wherein a cylindrical sensor head forming a measurement space is formed of an optically-transparent material. A side wall of the sensor head has accommodating spaces for accommodating a light source, transmitted light detector, and scattered light detector. An inner surface of the side wall of the sensor head is configured to serve as: an optical window for guiding inspection light to the measurement space; an optical window for guiding transmitted light to the transmitted light detector; and an optical window for guiding scattered light to the scattered light detector.

Abstract: A measuring device comprises a guard electrode that is arranged around a cathode, reduces oxygen that is not from an oxygen permeable membrane and inhibits the oxygen from reaching the cathode. The guard electrode is electrically connected to an anode through a resistor having a prescribed resistance.

Abstract: The present invention is intended to provide a turbidimeter having a simple and sturdy structure which is hard to break and exhibits excellent long-term stability by reducing a number of sealing positions, wherein a cylindrical sensor head forming a measurement space is formed of an optically-transparent material. A side wall of the sensor head has accommodating spaces for accommodating a light source, transmitted light detector, and scattered light detector. An inner surface of the side wall of the sensor head is configured to serve as: an optical window for guiding inspection light to the measurement space; an optical window for guiding transmitted light to the transmitted light detector; and an optical window for guiding scattered light to the scattered light detector.

Abstract: A fine particle measuring system for semiconductor cleaning fluid includes a sample tank for holding a sample of the cleaning fluid and a pump that can circulate the sample of cleaning fluid. A return conduit is connected to a filter and a bubble discharge opening member to return a major portion of the sample of cleaning fluid to the sample tank. A minor portion of the cleaning fluid is directed respectively to a cooling unit, and then to a deaerator for eliminating any effects of bubbles on the measurement of fine particles in the cleaning fluid. A first conduit is connected to a measuring cell to return the sample cleaning fluid to the sample tank while a second conduit is connected to the deaerator to draw gas from the bubbles that have been separated from the deaerator.

Abstract: An improved apparatus for measuring fine particles in a liquid includes a nozzle for spouting water from within one end of a cell towards an opposite end thereof. An incident light beam traverses the spouted water to scatter light towards a light detection system exteriorly of the cell. The detection system includes a stop for excluding scattered light from being detected and which resulted from fine particles outside a central portion of the spouted liquid.

Abstract: A particle counter for measuring the concentration and particle-size distribution of minute particles in a fluid by irradiating the particles with a laser beam from a direction that is substantially perpendicular to the fluid flow direction and by detecting the light scattered from the particles. The laser beam, prior to irradiating the particles, is flattened with a lens system and its otherwise Gaussian photointensity distribution is converted to a square pattern with a slit member. The light scattered from a central portion of the fluid is detected and formed into a real image with a focusing lens system and a detecting slit that cuts the real image only in the irradiating direction. The scattered light may be detected from a third direction that is substantially perpendicular to the flow direction and the irradiating direction.

Abstract: An apparatus for measuring particles contained in a sample liquid has a cylindrical cell having an incident light transmitting portion, a transmitted light transmitting portion diametrically aligned with the incident light transmitting portion, and a light transmitting portion at an angle to the diameter between the incident light transmitting portion and the transmitted light transmitting portion. An inlet at one end of the cell admits sheath flow liquid having the same index of refraction as the sample liquid, and an outlet is provided at the other end of the cell.