Abstract: A method and apparatus for analyzing fluid by a multi-fluid modulation mode is characterized by subjecting a plurality of sample fluids (which may be different or a single sample fluid divided into a plurality of systems) to a fluid modulation by reference fluids at various frequencies, respectively. An analytical portion provided with only one sensor is simultaneously and continuously supplied with the respective sample fluids. An output signal from the sensor in the analytical portion is divided into signal components of the respective modulation frequencies for the respective sample fluids to rectify and level, whereby obtaining analyzed values about the respective sample fluids is achieved.

Abstract: A method for analyzing fluid by a multi-fluid modulation mode is characterized by subjecting a plurality of sample fluids (which may be different or a single sample fluid divided into a plurality of systems) to a fluid modulation by reference fluids at various frequencies, respectively. An analytical portion provided with only one sensor is simultaneously and continuously supplied with the respective sample fluids. An output signal from the sensor in the analytical portion is divided into signal components of the respective modulation frequencies for the respective sample fluids to rectify and level, whereby obtaining analyzed values about the respective sample fluids is achieved.

Abstract: A method of measuring the quantity of an ingredient gas in the exhaust gas from a motor vehicle during each of a sequence of driving modes by measuring and storing in real time flow rate data Q.sub.E (t) representative of the flow rate of the exhaust gas at a succession of times during a driving mode, measuring and storing concentration data representative of the concentration of the ingredient gas in the exhaust gas during a time period delayed with respect to the time period of the driving mode in order to compensate for a time delay in correspondence between changes in flow rate and performing an interpolation method and either a data-compression or data-expansion method on the concentration data in order to obtain corrected concentration values C.sub.E (t) on a one-to-one basis in phase and magnitude to the flow rate data, and determining the quantity M(t) of the ingredient gas in the exhaust gas for each of the measurements of flow rate based on the operational equation M(t)=.rho..times.C.sub.E (t).

Abstract: A non-dispersion type infrared analyzer for simultaneously determining plural components of a sample fluid, wherein a standard fluid and a sample fluid are alternately supplied in a cell and a plurality of pneumatic detectors, each of which corresponds respectively to one component to be determined, are arranged optically in series with respect to a light source. The extremely troublesome zero-adjustment, adjustment of the phases and re-adjustment of the compensation for eliminating the influences of interference components due to changes in the zero-drift or the deviation of phases are not required.

Abstract: An apparatus for analyzing oxygen, nitrogen and hydrogen which are contained in metals. The apparatus includes a graphite crucible which has a sample therein and which is heated to generate a gaseous mixture of CO, N.sub.2 and H.sub.2. An oxidizer is used to oxidize the CO and H.sub.2 into CO.sub.2 and H.sub.2 O, respectively. The apparatus further includes a thermal conductivity detecting means for detecting CO.sub.2, N.sub.2 and H.sub.2 O, coming from a first gas-chromatographic column which is used for separating H.sub.2 O from the CO.sub.2 and N.sub.2. A second gas-chromatographic column is used for separating CO.sub.2 from N.sub.2. A passage change valve is used for back-flushing the first column. Helium is preferably used as the carrier gas. The apparatus is simple and operates quickly because the three components, O, N and H, can be measured by using a single carrier gas He and a single sample and thus, only a single measurement operation is required.