CARBON DIOXIDE SENSING SYSTEM

• US 3,754,867 A
• Filed: 09/20/1971
• Issued: 08/28/1973
• Est. Priority Date: 12/11/1970
• Status: Expired due to Term

• Current Assignee: Karl R. Guenther
• Original Assignee: Karl R. Guenther
• Inventors: Guenther, Karl R.
• Primary Examiner(s): Wolk, Morris O.
• Assistant Examiner(s): Serwin, R. E.
• Application Number:
  US05/181,834
• Time in Patent Office: 708 Days
• Field of Search: 23/254E,232E,253TP
• US Class Current: 422/91
• CPC Class Codes: G01N 21/783 for analysing gases
• CPC Class Codes: G01N 33/0027 concerning the detector
• CPC Class Codes: Y10T 436/204998 Inorganic carbon compounds

Abstract

Low cost system for sensing carbon dioxide content of ambient air. It comprises a thin layer of a chemical reversibly absorbent for carbon dioxide, the pH of which changes in relation with the amount of absorbed carbon dioxide at any time; an indicator present in said film which changes color in accordance with the pH, and a photoelectric system to produce an electric signal proportionate to said color change. In this system substantial independence of humidity is gained by the use as principal solvent in the said thin layer of an ionizing solvent having a vapor pressure in the range of 0-10 mm at temperatures up to 150*F, and compatible with the other components of the system.

Claims

2. The gas analyzer of claim 1, in which the said translucent layer consists of one sensor layer and one gas permeable protective film.

3. The gas analyzer of claim 2, in which said translucent layer is less than 20 mil thick and said permeable protective film is less than 10 mil thick.