The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 01, 1980
Filed:
Mar. 07, 1978
Frank Kitzinger, Montreal, CA;
Noranda Mines Limited, Toronto, CA;
Abstract
An apparatus for detecting the presence of a specific substance in a gas stream is disclosed. The apparatus comprises a sensing chamber adapted to receive a test paper which is subject to coloration when contacted by a specific substance in a gas contained in the sensing chamber, means for generating a light beam and directing it toward the test paper in the sensing chamber, a light beam sensing device responsive to the extent to which the test paper in the sensing chamber undergoes coloration in response to exposure to the specific substance in the gas stream, an amplifier connected to the light beam sensing device for providing an output voltage which is proportional to the coloration of the test paper, and means connected to the amplifier for providing an output signal which is an instantaneous indication of the concentration of the substance to be monitored, comprising a signal conditioning circuit connected to the amplifier for providing an output which is a linear function of the cumulative amount of the substance to be detected contacting the test paper, and a differentiator responsive to the output of said amplifier for deriving the instantaneous concentration of the substance in the gas stream. The apparatus is further provided with a beam splitter for dividing the light beam into two separate beams, one directed toward the test paper in the sensing chamber and the other toward a variable optical density filter, and a second light beam sensing device responsive to the transmittance of the variable optical density filter. The amplifier is responsive to the two light beam sensing devices for providing an output which is a function of the ratio of the light sensed by the two light sensing devices irrespective of the light source intensity variations. An automatic zero adjustment device is also provided for resetting the output of the amplifier to zero prior to taking measurements.