Chemical apparatus and process disinfecting – deodorizing – preser – Analyzer – structured indicator – or manipulative laboratory... – Means for analyzing liquid or solid sample
Patent
1996-07-25
2000-02-15
Scheiner, Laurie
Chemical apparatus and process disinfecting, deodorizing, preser
Analyzer, structured indicator, or manipulative laboratory...
Means for analyzing liquid or solid sample
422 8213, 422 83, 422 98, 422 50, 204406, G01N 2730
Patent
active
060249226
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to an oxygen analyzer suitable for use in the oxygen analysis of gases containing very small amounts of oxygen.
BACKGROUND ART
With the increasing scale of integration of semiconductor circuits, as well as the advances in the technology of ultrahigh precision working, it has become necessary to keep surveillance of the fabrication process, particularly for the oxygen concentration of the process gas which need be monitored over the range from the ppb to sub-ppb level. In such precision measurements, even the oxygen analyzers that have heretofore been used without any problems are found to cause various problems and need be improved.
Among the problems that need be dealt with are that of back flow due to the pressure difference between a pipe for entrance gas to the detector and a pipe for exit gas, the problem of back diffusion of aerial oxygen from the pipe exit gas, the problem due to the dead zones in the apparatus and, further, the problem of dissolved oxygen in the water to be additionally supplied to the detector. As typified by these problems, it has been found that the results of measurements are affected by the presence of such small amounts of oxygen as have been insignificant to the conventional oxygen analyzers.
The present invention has been accomplished with a view to meeting these rigorous requirements. In order to enable precise measurements, the present inventors searched for certain factors of variations ascribable to the analyzer, located the causes of such variations and have proposed effective countermeasures. Thus, the problems to be solved by the invention are novel ones that have been first identified by the present inventors. It should be noted that the term "very small amounts" as used with oxygen in the specification refers to concentrations of no more than about 1 ppm.
DISCLOSURE OF THE INVENTION
The oxygen analyzer of the invention is suitable for use in the oxygen analysis of gases containing very small amounts of oxygen and it features various improvements typified by a bypass pipe coupling between a pipe for gas supply to a detector and a pipe at gas outlet, a check valve provided halfway said bypass pipe and means for detecting the pressure difference between said gas supply pipe and said gas outlet pipe.
It should also be noted that the oxygen analyzer to be used in the invention is of a Hersch galvanic type and contains an aqueous solution (electrolyte) of a specified concentration range within a detector; the operating principle of the analyzer is such that the oxygen in a feed gas undergoes chemical reaction with the water in the electrolyte, whereby an electric current flows between electrodes in the electrolyte to permit the measurement of oxygen concentration. It should further be noted that the detector is capable of being supplied with a gas to be measured, a zero gas and a gain gas and these feed gases can be switched from one type to another by suitable means such as a valve. For the parts that are not particularly mentioned in the specification, any parts of and means in known oxygen analyzers may be applied.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram showing a prior art oxygen analyzer having no bypass line;
FIG. 2 is a diagram showing the oxygen analyzer of the invention having a bypass line;
FIG. 3 is a diagram showing the line configuration of the prior art analyzer, as well as the arrangement of valves used for switching between lines;
FIG. 4 shows a diagram showing the configuration of a combination valve; and
FIG. 5 is a diagram of an oxygen analyzer that has an automatic water replenisher, as well as a device for purging a water tank as with an effluent gas from a detector.
BEST MODE FOR CARRYING OUT THE INVENTION
The inventions recited in the respective claims are hereunder described seriatim.
The invention recited in claim 1 relates to an oxygen analyzer suitable for use in the oxygen analysis of gases containing very small amounts of oxygen and it is characterized by having a bypass pipe c
REFERENCES:
patent: 3698384 (1972-10-01), Jones
patent: 3760831 (1973-09-01), Colvin
patent: 3933593 (1976-01-01), Sternberg
patent: 4657737 (1987-04-01), Kampelmuhler
patent: 4973395 (1990-11-01), Mayer et al.
patent: 5312761 (1994-05-01), Suzuki et al.
"Testing Methods for Determination of Trace Components in Diluent Gas and Zero Gas"; Japanese Industrial Standard JIS K 0225--1990.
Hersch/Osaka Oxygen--PPB Oxygen Analyzer, MKIV/Y; Galvanic-cell Type, Osaka Sanso Kogyo Ltd., dated Sep. 1, 1993.
Hersch/Osaka Oxygen--MKIV/S, Trace Oxygen Gas Analyzer, Osaka Sanso Koygo, Ltd., dated Aug. 1, 1993.
Matsumoto Yoshiro
Tanaka Yoshiyasu
Osaka Sanso Kogyo Ltd.
Parkin J. S.
Scheiner Laurie
LandOfFree
Method of controlling an oxygen analyzer of the Hersch galvanic does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of controlling an oxygen analyzer of the Hersch galvanic , we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of controlling an oxygen analyzer of the Hersch galvanic will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1903370