A.J. Morse & Son US Navy Helium Helmet w/Double Exhaust Valve

Product Features

A.J. Morse & Son Was one of three Mark V helmet manufacturers building the Helium helmet variant. We have never seen or heard of a US Navy Helium Helmet being made by Miller Dunn. The design was introduced just before WWII. The early version had an exhaust tube running from a Mark V exhaust valve assembly to the back of the helmet jus above the canister. It was found that any leakage back into the helmet through the exhaust could allow salt water to mix with the carbon dioxide scrubber media. This would cause a chemical reaction which could injury or kill a diver. In the early 1950s the Navy designed a secondary exhaust valve with two rubber flapper disks stacked in a housing at the end of the duct. Those flapper disks were from the exhaust valve of the Jack Browne Mask exhaust. Today double exhaust valves are standard on diving helmets to protect divers form exposure to contaminated water. The base helmet for this Helium helmet is the AJMS Mark V. It is built using the US Navy plans from 1942.