Maurice Fernez

Maurice Fernez (30 August 1885 - 31 January 1952, Alfortville, Paris, France) was a French inventor and pioneer in the field of underwater breathing apparatus, respirators and gas masks. He was pivotal in the transition of diving from the tethered diving helmet and suit of the nineteenth century to the free diving with self-contained equipment of the twentieth century. All Fernez invented apparatus were surface-supplied but his inventions, especially his mouthpiece equipped with a one-way valve, inspired the scuba diving pioneer Yves le Prieur. He was also a talented businessman who created a company to manufacture and sell the breathing apparatus he invented, and expanded its range of products to include gas masks, respirators and filters.

After a traumatic accident during childhood play when he was thrown into water and injured his foot, which left him with a lifelong limp, Fernez became fascinated with creating a device which would enable a swimmer to stay under water for a few minutes to help save drowning people. This should be a light and simple device which could be quickly put into action, unlike the heavy traditional equipment of diving suit and massive metal helmet. From 1905 Fernez experimented with devices for breathing underwater.

Fernez's first idea was a rubber balloon connected to the swimmer's mouth with a tube. The idea was that this would provide a reservoir of air which could be breathed in and out. But Fernez quickly realised that this worked for only two or three breaths. His next idea was to use a flexible rubber tube connecting the diver's mouth to an air intake on the surface supported by a float. Fernez registered a patent on this invention on 14 May 1912, which was granted on 22 July 1912. The swimmer's end of the tube had a T shaped mouthpiece, one side connected to the air hose through a one way (non-return) valve, the other side to an exhaust with a "duck bill" check valve. Fernez's idea was that the divers normal inhalation would be sufficient to draw air down the tube through the one way valve, and his exhalation to expel used air through the exhaust.

Fernez soon found that beyond a depth of one metre, or at most a metre and a half, inhaling air down the tube and exhaling it thorough the exhaust valve becomes impossible because of the pressure of water compressing the chest. He quickly realised that the air needed to be supplied to the diver under sufficient pressure to balance the pressure of the water at whatever depth the diver was operating. He added a manual Michelin air pump, the type used to inflate car tyres, to pump air down the tube, and also a clamp for the diver's nose to prevent water entry, and goggles to protect the eyes and permit underwater vision. Air was pumped continuously down the tube and flowed out of the exhaust valve of the mouthpiece, causing the pressure in the mouthpiece to be exactly the same as the external water pressure. The diver could breathe in and out from this stream of air without difficulty. This breathing apparatus was called the Fernez model 1.

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