CARBON DIOXIDE ABSORPTION SYSTEMS FOR SCUBA 2. THEORY AND APPLICATIONS OF A NOVEL, NON-CYLINDRICAL LOW-RESISTANCE, CO2 ABSORPTION CANISTER FOR SCUBA. RES REP 4-65.

Abstract

Abstract : Results of underwater swimming experiences, breathing-machine experiments, and recompression-chamber testing to eleven atmospheres absolute pressure (330 feet sea water) with new SCUBA carbon dioxide absorption canisters are reported. Granular Baralyme was employed as the chemical absorbing agent. Certain comparisons, both of design and functional history, with conventional cylindrical canister systems are emphasized and analyzed, and theory of the low-resistance device is discussed. As a three-dimensional geometric solid, the essential canister shape is that of a frustum of a rectangular pyramid. In the two-dimensional aspect of greatest surface the canister perimeter presents as a truncated isosceles trapezoid. Inlet and exhaust hose fittings are situated near the extremes of the larger rectangular base of the canister. The acronyms FLATCAN and Flatcanister denote Flat, Low resistance, carbon dioxide Absorption, Trapezoidal Canisters. Mean delta and resistance results for nine cylindrical canisters (16 mechanical respirator experiments) are about 90% and 15% higher, respectively, than the comparable mean data for seven FLATCAN prototypes (15 respirator experiments). A Reynolds number comparison, measured with a Fisher t test, was significant at the 0.01 confidence level. Size and dimensional parameters have been empirically related to duration of satisfactory carbon- dioxide elimination from SCUBA systems.