Infrared radiation gas analyzer

• US 4,501,968 A
• Filed: 03/02/1983
• Issued: 02/26/1985
• Est. Priority Date: 03/09/1982
• Status: Expired due to Fees

• Current Assignee: Horiba Limited
• Original Assignee: Horiba Limited
• Inventors: Ebi, Hiroyuki, Miyatake, Kimio
• Primary Examiner(s): Howell, Janice A.
• Application Number:
  US06/471,455
• Time in Patent Office: 727 Days
• Field of Search: 250/338 R, 250/343, 250/347, 250/352, 356/437
• US Class Current: 250/343
• CPC Class Codes: G01J 5/60 using determination of colour temperature
• CPC Class Codes: G01N 21/314 with comparison of measurements at specific and non-specific wavelengths dual wavelength spectrometry G01J3/427
• CPC Class Codes: G01N 21/71 thermally excited

Abstract

An infrared radiation gas analyzer for determining the concentration of an ingredient in a sample gas has a sample gas container for containing a sample gas at a temperature at which the ingredient the concentration of which is to be determined will emit infrared radiation in a range characteristic of the ingredient and a window for allowing the infrared radiation to escape from the container. A pair of filters is provided, one of the filters transmitting only radiation in the range and the other of the filters transmitting only radiation in a range near to the firstmentioned range. A disc with the filters thereon rotates in front of the window for passing the filters across the path of radiation escaping from the container. An infrared radiation detector is positioned for receiving the radiation passed by the respective filters and emitting a pulsed signal, which is fed to a comparator for determining the difference between or the ratio of the respective pulses of the signal as an indication of the concentration of the ingredient the concentration of which is to be determined in the sample gas.

Claims

1. An infrared radiation gas analyzer for determining the concentration of an ingredient in a sample gas, comprising:

a sample gas containing means for containing a sample gas at a temperature at which the ingredient the concentration of which is to be determined will emit infrared radiation in a range characteristic of the ingredient and means for allowing said infrared radiation to escape from said containing means;

a pair of filters, one of said filters transmitting only radiation in said range and the other of said filters transmitting only radiation in a range near to said firstmentioned range;

means for alternately passing said filters across the path of radiation escaping from said containing means;

an infrared radiation detector positioned for receiving the radiation passed by said respective filters and emitting a pulsed signal;

means for determining the difference between or the ratio of the respective pulses of said signal as an indication of the concentration of the ingredient the concentration of which is to be determined in the sample gas.

2. An infrared radiation gas analyzer as claimed in claim 1 in which said sample gas containing means is a sample gas container having heating means for heating a sample gas in said container.

3. An infrared radiation gas analyzer as claimed in claim 1 in which said sample gas containing means is a pipe for carrying a heated gas from a source of heated gas.

4. An infrared radiation gas analyzer as claimed in claim 1 in which said means for passing said filters comprises a rotatable disc having said filters thereon spaced circumferentially of said disc.