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The original Amphibian triple
purpose apparatus, i.e. for use in poison gas or under water, consist of
a steel cylinder, charged with pure oxygen for depths not exceeding 30
feet; CO2 absorbent chamber, mouthpiece, noseclip, goggles, a
streamlined bag, with excess air escape valve; and- for the use under
water only- a lead balance-weight at back, jock strap, etc. For use at
greater depths, a mixture of oxygen and air, or of oxygen and helium is
used in certain proportions according to the depth at which the diver
has to work. (note: first trimix dives?) In some cases the gases are in
separate cylinders, each with its own reducing valve set to deliver the
gases in correct proportion. In the modified Amphibian apparatus the
excess air of exhaust valve is fitted in front of the wearer, over his
shoulder, so as to be more readily accessible. While still of the
automatic type, like the more remotely placed valve, the new arrangement
also enables the valve to be controlled by hand. |
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