Émile Gagnan – Co-Inventor of the Diving Regulator

The diving world owes a debt to genius of Émile Gagnan and Jacques-Yves Cousteau, a French Navy diver. Both men developed the diving regulator – also known as the demand valve – which is responsible for reducing pressurized breathing gas into ambient pressure then sends this back to the diver. Their invention was used for the Aqua-Lung – a scuba equipment which was the first open-circuit, self-contained underwater breathing apparatus (SCUBA) to gain popularity and worldwide success – in 1943. Of course, the Aqua-Lung is now better known as a diving regulator.

Born in the French province of Burgundy in November 1900, Gagnan went to technical school where he finished in the early 1920s. He is an engineer and chose employment with Air Liquide, a large gas-supply firm. With Air Liquide, he specialized in high-pressure pneumatic design.

Together with Cousteau, they invented the Aqua-Lung in Parish during the winter of 1942-1943. Both met through Gagnan's boss who was also Cousteau's father-in-law, Henri Melchior. Gagnan was able to miniaturize and adapt an underwater breathing regulator patented by Benoit Rouquayrol to gas generators. Melchior was aware that his son-in-law was searching for an automatic demand regulator that increases the useful period of the underwater breathing apparatus invented by Commander Yves le Prieur.

Their invention was called “Scaphandre Autonome” or better known as Aqua-Lung. It was first released in 1946 in France where its identification code was CG45. The C stands for Cousteau while the G represents Gagnan while 45 means 1945, the year of the patent.

Shortly after the release of the Aqua-Lung – a year to be exact (1947) – Gagnan moved his family to Montreal, Canada. There he was employed by Canadian Liquid Air Ltd. During his stay there, he put up a lab and went on to design, engineer, prototype and patent a large number of SCUBA equipment. In fact, a lot of the scuba regulators existing today are derived from Gagnan's work.