PRELIMINARY EVALUATION OF MSA DILUTER DEMAND AN-R-5 REGULATORS. SERIAL NOS. 45-64 AND 45-67.
NAVAL SCHOOL OF AVIATION MEDICINE PENSACOLA FLA
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Two MSA AN-R-5 regulators were tested for performance. One of them, Serial No. 45-64 was found to have an internal leak. Consequently tests could not be made satisfactorily on the Aro Test Stand and a chamber experiment was not run on it. The other regulator, Serial No. 45-67, met the Navy requirements in the airoxygen ratio tests. The suction necessary for the tested flows of 45 and 70 1pm was very low the maximum suction being .25 inches of water. Related to this was the finding that the demand valve did not reseat completely at the end of inhalation. When suction was released the demand valve remained open and there was a continuous leak. This was noted when testing the regulator in the laboratory and also while using it in the chamber. This regulator was also used at altitude in the low pressure chamber and the subjects hemoglobin oxygen saturation checked with a Coleman oximeter. The saturation remained normal throughout the run. Author