Osaka Sanso Kogyo Ltd.

Akira Makihara

Takahiko Kijima

Edward Frederick Ezell

Junichi Nishizawa

Yoshiro Matsumoto

Hiroshi Nakamura

Shigeki Hayashi

Ken Ohmae

Shigeru Kikuchi

Juinchi Nishizawa

A method for analyzing the oxygen concentration of a gas with an oxygen concentration analyzer of such a type that a probe sensor, when supplied with a gas to be analyzed, produces an electrical output which is proportional to the concentration of oxygen in the gas, comprising the steps of preparing a first gas mixture in which an oxygen-free gas and a sample gas are mixed at a certain flow ratio and a second gas mixture in which the oxygen-free gas and the sample gas are mixed at a different flow ratio than in the first gas mixture, passing the first gas mixture and the second gas mixture asynchronously into the probe sensor, and comparing the electrical outputs from the sensor for the first gas mixture and the second gas mixture, as well as the proportions of the flow of the sample gas in the first gas mixture and the second gas mixture to thereby calculate the oxygen concentration in the sample gas. The method eliminates the need to perform frequent zero adjustment and enables the oxygen concentration in the sample gas to be measured with consistent results.

Method for analyzing the oxygen concentration of a gas

Method of measuring the dew point or frost point of a gas having low

The invention relates to an apparatus for determining the frost point of a gas containing a very small amount of water. The apparatus comprises (I) compartment A made of a good heat conductor; (II) an inlet for the gas to be measured, which inlet is provided on compartment A; and (III) a heater for adjusting the temperature in compartment A, and a temperature sensor. The apparatus further comprises (IV) compartment B which is adjacent to compartment A. At least part of compartment B is made of a poor heat conductor. Further, the apparatus comprises (V) a hole at the interface between compartments A and B and (VI) a reflector mirror having a temperature sensor. The reflector mirror is provided on compartment B in such a way as to cover the hole is connected thermally to a freeze source in such a way that the temperature of the reflector mirror can be varied from room temperature to at least -80.degree. C. Also, the apparatus comprises (VII) a gas outlet provided on compartment B; (VIII) a small gap formed between the hole and the reflector mirror; (IX) a device that allows convergent rays of light or laser light to be emitted onto the surface of the reflector mirror; and (IX) a photodetector equipped with a condenser lens. The condenser lens condenses light from frost formed on the surface of the reflector mirror when said gas to be measured contacts said mirror and said water in said gas condenses as frost. Finally the apparatus comprises (XI) a detector device that senses the temperature at which frost occurs on the reflector mirror.

Apparatus for measuring the dew point or frost point of a gas having low

A method of determining the dew point of a gas containing a very small amount of water using (1) a reflector mirror the temperature of which can be varied from room temperature down to at least -80.degree. C.; (2) a source of condensed rays of light for irradiating the reflector mirror; and (3) a light recovering device that detects changes in scattered light due to condensation on the reflector mirror by exposing the mirror to the gas. The method comprises cooling the mirror and detecting the temperature at which the scattered light has a maximum intensity; slowly raising the temperature and detecting the temperature at which the scattered light has a minimum intensity and repeating the cycle until the temperature at which the intensity is a maximum and the temperature at which the intensity is a minimum are almost the same.

Method and apparatus for measuring the dew point and/or frost point of a

A method of cleaning a reflector mirror in an optical dew point meter that measures the dew point or frost point of a sample gas by a process including the steps of bringing the sample gas into contact with the reflector mirror whose temperature is variable, projecting condensed rays of light or laser light onto said reflector mirror, and detecting the change in the intensity of scattered light and/or reflected light on account of the dew or frost formed on said reflector mirror, characterized by bringing a CO.sub.2 gas or a CO.sub.2 containing gas into contact with the reflector while the latter is in a cooled state, thereby condensing CO.sub.2 on the surface of the reflector mirror, and the subsequent step of heating the reflector mirror to vaporize the CO.sub.2 is dischosed.

Method of cleaning the reflector mirror in an optical dew point meter

An improved oxygen analyzer device is disclosed which comprises a gas flow passage having inlet and exhaust ports, an oxygen concentration detector in proximity to the exhaust port and first and second parallel intermediate flow passages, one of which contains a purifier to remove oxygen from the gas flowing therethrough. The device is characterized by the use of metal, diaphram-type, three-way valves in the branch-off and junction points between the intermediate flow passages. The valves eliminate dead space in conventional devices that extends both the calibration and analysis time of such devices.

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Chiba, Japan

Akira Makihara