Accession Number : AD0655936

Title :   ELECTROCHEMICAL CARBON DIOXIDE SENSOR.

Descriptive Note : Final rept. Oct 65-Oct 66,

Corporate Author : IONICS INC WATERTOWN MASS

Personal Author(s) : Leitz,Frank B.

Report Date : MAY 1967

Pagination or Media Count : 55

Abstract : The purpose of the program was to develop a novel carbon dioxide sensor based on obtaining changes in the electrical resistance of anion-exchange resin proportional to the ambient partial pressure of carbon dioxide. The change in resistance is due to the increased ionization of a weakly ionized base in the presence of a sightly acid gas. A laboratory program was conducted to evaluate the response of various types of weak-base ion-exchange polymers to carbon dioxide concentrations in the range of 0 to 4%. The optimum material consisted of a condensation polymer of resorcinol, formaldehyde and triethylenetetramine. A laboratory model of the CO2 Sensor was fabricated using these sensing elements in the form of small, thin strips. In order to minimize the effects of humidity and temperature, the model contained two sensing elements, one being a reference. A guard chamber was provided to absorb any strongly-acid gases. Electrical readout is made on a balancing potentiometer with an earphone detector. The Sensor is small (about 50 cubic inches), weighs less than 6 ounces, has a power requirement of less than 0.5 watts, and its operation is independent of gravity. (Author)

Descriptors :   (*GAS ANALYSIS, INSTRUMENTATION), (*CARBON DIOXIDE, DETECTORS), ELECTROCHEMISTRY, ION EXCHANGE RESINS, ELECTRICAL RESISTANCE, BASES(CHEMISTRY), IONIZATION, MEMBRANES, CONCENTRATION(CHEMISTRY)

Subject Categories : Industrial Chemistry and Chemical Processing
      Life Support Systems

Distribution Statement : APPROVED FOR PUBLIC RELEASE