Optical gas detector

• US 8,253,942 B2
• Filed: 09/27/2007
• Issued: 08/28/2012
• Est. Priority Date: 09/27/2007
• Status: Active Grant

• Current Assignee: Teledyne Detcon, Inc. (Teledyne Technologies Incorporated)
• Original Assignee: Scott Technologies, Inc. (3M Company)
• Inventors: Bristol, L. Rodney
• Primary Examiner(s): Toatley, Gregory J
• Assistant Examiner(s): VALENTIN II, JUAN D
• Application Number:
  US11/862,959
• Publication Number:
  US 20090086191A1
• Time in Patent Office: 1,797 Days
• Field of Search: None
• US Class Current: 356/437
• CPC Class Codes: G01N 21/0303 Optical path conditioning in cuvettes, e.g. windows; adapted optical elements or systems; path modifying or adjustment G01N21/031 - G01N21/15 take precedence
• CPC Class Codes: G01N 21/3504 for analysing gases, e.g. multi-gas analysis
• CPC Class Codes: G02B 27/1073 characterized by manufacturing or alignment methods
• CPC Class Codes: G02B 27/144 using partially transparent surfaces without spectral selectivity G02B27/147 takes precedence

Abstract

A gas detector is provided. The gas detector includes a measurement source of optical radiation, a reference source of optical radiation, a measurement detector configured to provide an output signal indicative of a gas of interest, a reference detector configured to provide an output signal at least partially independent of the gas of interest, a measurement optical path extending from the measurement source to the reference and measurement detectors, and a sample region for receiving a gaseous sample. The sample region is located along the measurement optical path. A window is positioned in the measurement optical path downstream from the measurement source and upstream from the reference and measurement detectors. The window is partially transparent to optical radiation and partially reflective to optical radiation. The window is positioned to either reflect a portion of the optical radiation emitted by the reference source into the measurement optical path or to allow a portion of the optical radiation emitted by the reference source to pass through the window into the measurement optical path.

Claims

1. A gas detector comprising:

a measurement source of optical radiation;

a reference source of optical radiation;

a measurement detector configured to provide an output signal indicative of a gas of interest;

a reference detector configured to provide an output signal at least partially independent of the gas of interest; and

a beam splitter partially transparent to optical radiation and partially reflective to optical radiation, the beam splitter being configured to allow a portion of the optical radiation emitted by both the reference and measurement sources to pass therethrough to one of the measurement detector and the reference detector, the beam splitter being configured to reflect a portion of the optical radiation emitted by both the reference and measurement sources to the other of the measurement and reference detectors.

2. The gas detector according to claim 1, wherein the beam splitter is configured to allow approximately the same amount of optical radiation from the measurement source and the reference source to pass therethrough, and the beam splitter is configured to reflect approximately the same amount of optical radiation from the measurement source and the reference source.