Infrared ray gas analyzing apparatus

Abstract

An infrared type gas analyzer having measuring and reference cells is equipped with alternately switchable valves so that the cells can alternate acting as the measuring and reference cells. The output of the detector is stored for each configuration and these outputs are subtracted from one another to provide the output of the analyzer.

Description

BACKGROUND OF THE INVENTION

This invention relates to an infrared ray gas analyzing apparatus in which the infrared ray wavelength absorption characteristics inherent in various gases are utilized for measuring the amount of energy absorbed, to thereby subject a sample gas to quantitative analysis.

In general, an infrared ray gas analyzer is extensively used for analyzing various gases because it is excellent in stability and reliability. For instance, it is used for detecting a minute quantity gas contained in the air, or the low density CO gas in the air for the purpose of circumstancemeasurementmeasurement sample gas and the reference gas. The advantages of this effect should be well appreciated. Furthermore, as the measurement sample gas and the reference gas are alternately allowed to flow in the first cell and the second cell, the contamination of these cells is uniform and, thus, the optical balance is substantially maintained at all times.

With respect to the reference gas, the analysis component is eliminated by means of the low temperature combustion furnace; however, besides combustion, various chemical reactions and absorption may be readily employed. In the embodiment, the converter for converting CO gas into CO₂ is employed; however, if a converter for converting H₂ S gas into SO₂ gas or a converter for converting NH₃ gas into NO gas is employed, then H₂ S or NH₃ gas may be subjected to analysis. In this case, it is used as a SO₂ analyzer in which the gas passing through the converter is the reference case and the other gas is the sample gas. If a hydrogen carbide absorbent or a SO₂ absorbent is utilized, the apparatus may be employed as a hydrogen carbide meter or a SO₂ meter. Furthermore, the same object can be achieved by supplying the reference gas from a standard gas cylinder separately provided. In addition, the output holding function and the differential operation function may be achieved by using a digital computer or the like.

Claims

1. An infrared ray gas analyzing apparatus of the type having a first cell irradiated by a first light beam of infrared rays, a second cell irradiated by a second light beam of infrared rays, a gas suppy means for supplying a sample gas to said first cell during a first period of time and a reference gas to said first cell during a second periof of time, a detector for receiving and comparing said first and second light beams passed through said first and second cells and providing an output signal, and a signal process circuit having a first output signal holding circuit for storing the output of said detector during said first period of time, a second output signal holding circuit for storing the output of said detector during said second period of time and a differential amplifier to which the outputs of said first and second signal holding circuits are applied, said amplifier providing the analyzer output signal, wherein the improvement comprises:

said gas supply means supplying said reference gas to said second cell during said first period of time and supplying said sample gas to said second cell during said second period of time.

2. An infrared gas analyzing apparatus according to claim 1, wherein said gas supply means comprises:

first and second gas inlet passages for providing gas to said first and second chambers, respectively;

first and second three-way valves each having one input and two outputs, each of said three-way valves having one output connected to each said inlet passage;

a reference gas source for supplying reference gas to the inlet of said first three-way valve;

a sample gas source for supplying sample gas to the inlet of said second three-way valve; and

valve control means for controlling said first and second three-way valves to thereby supply said reference and sample gases to opposite inlet passages during said first and second periods of time.

3. An analyzing-apparatus using infrared rays for measuring the density of an analysis gas in a sample gas comprising: a first cell irradiated by a first light beam of infrared rays; a second cell irradiated by a second light beam of infrared rays; means for receiving said first and second light beams passed through said first and second cells and providing an output signal in response thereto indicative of a density of the analysis gas contained in said sample gas being measured; and gas supply means for periodically supplying said sample gas containing said analysis gas to one of said first and second cells and a reference gas to the other of said first and second cells and, alternately, supplying said sample gas to said other of said first and second cells and said reference gas to said one of said first and second cells.

4. An infrared gas analyzing apparatus according to claim 3, wherein said gas supply means comprises: first and second gas inlet passage for providing gas to said first and second cells, respectively; first and second three-way valves each having one input and two outputs, each of said three-way valves having an output connected to each said inlet passage; a reference gas source for supplying reference gas to the input of said first three-way valve; a sample gas source for supplying sample gas to the input of said first three-way valve; and valve control means for controlling said first and second three-way valves to alternately supply said reference and sample gases to opposite inlet passages.