Yves Le Prieur | |
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| Born | 23 March 1885 Lorient, France |
| Died | June 1, 1963 (aged 78) Nice, France |
| Allegiance | France |
| Service/ | French Navy |
Yves Paul Gaston Le Prieur (23 March 1885 – 1 June 1963) was an officer of the French Navy and an inventor.
Yves Le Prieur | |
|---|---|
| | |
| Born | 23 March 1885 Lorient, France |
| Died | June 1, 1963 (aged 78) Nice, France |
| Allegiance | France |
| Service/ | French Navy |
Yves Paul Gaston Le Prieur (23 March 1885 – 1 June 1963) was an officer of the French Navy and an inventor.
Le Prieur followed his father in joining the French navy. As an officer he served in Asia and used traditional deep sea diving equipment. He studied Japanese and became sufficiently proficient to be promoted to military attaché and translator at the French embassy in Tokyo. While there he became the first Frenchman to earn a Black belt in judo, and the first person to take off in a plane, a glider, from Japanese soil in 1909.
The glider, named Le Prieur No. 2 after an earlier No. 1 unmanned prototype, was 7.2 m long, 7.0 m wide, and weighed 35 kg. The frame was made of Japanese bamboo, which was covered with calico. Le Prieur had designed the glider in collaboration with Shirou Aibara, a Lieutenant of the Japanese Navy, and Aikitsu Tanakadate, a professor at Tokyo Imperial University. The first flight took place in December 1909 just to the East of the University of Tokyo at Shinobazu Pond with Le Prieur sitting on the glider's main wing. The first flight covered 200 m at an altitude of 10 m. [1]
During the First World War he invented the plane-mounted Le Prieur rocket launcher for bringing down observation balloons. This weapon system, which allowed an airplane to fire a single volley of rockets in close succession (the design planned for simultaneous launch, but technical unreliability made it impossible in 1916) was remarkably effective against the German observation balloons, and was only phased out when tracer rounds and incendiary bullets for the on-board machine guns (with similar efficiency and larger ammunition capacity) became widespread among the Allied air forces near the very end of the war. [2]
Le Prieur also patented a number of designs for mechanical lead computing sights for both ship to ship and anti-aircraft guns.
In 1925 Le Prieur saw a demonstration at the Industrial and Technical Exhibition in Paris of a diver using a breathing apparatus invented by Maurice Fernez. The Fernez breathing apparatus consisted of a simple T-shaped rubber mouthpiece. On one side this was connected to a long tube down which air was pumped from the surface. On the other side of the mouthpiece, excess and exhaled air escaped from a simple rubber "ducks bill" valve. The diver's nose was pinched by a pair of spring clamps ("pince nez") to prevent ingress of water, and his eyes were protected by small goggles with rubber surrounds.
Le Prieur was impressed by the simplicity of the Fernez equipment and the freedom it allowed the diver, and he immediately conceived an idea to make it free of the tube to the surface pump by using Michelin cylinders as the air supply. Michelin cylinders contained three litres of air compressed to 150 kilograms per square centimetre (2,100 psi) supplied by Michelin to garages without air compressors for inflation of car tires. Le Prieur approached Fernez, who cooperated to modify his equipment to Le Prieur's idea, and on 6 August 1926 the "Fernez-Le Prieur" diving apparatus was demonstrated at the swimming pool of Tourelles in Paris. The unit consisted of a cylinder of compressed air carried on the back of the diver, connected to a pressure regulator designed by Le Prieur adjusted manually by the diver, with two gauges, one for tank pressure and one for output (supply) pressure. Air was supplied continually to the mouthpiece and ejected through a short exhaust pipe fitted with a valve as in the Fernez design. For the first time a man could breathe underwater with no connection to the surface at all – Le Prieur had invented the open circuit self-contained underwater breathing apparatus – scuba. [3]
Fernez's separate goggles didn't allow a dive deeper than ten metres because they were not pressurised, so as the diver went deeper the goggles were squeezed onto his face and eyeballs by the increasing water pressure, a phenomenon known as "mask squeeze". In 1933, Le Prieur replaced the Fernez goggles, noseclip and valve by a full face mask, directly supplied from the air cylinder, which balanced the pressure in the mask with the external water pressure. Le Prieur remarked that the diver could breathe through the mouth or nose, or both, at will, and that it was even possible to speak with another diver by bringing the glass close to their ear, the glass forming a microphone. [3]
In 1934 Le Prieur was granted French patent 768083 for an improved hand-controlled self-contained underwater breathing apparatus with full face mask. [4] The equipment delivered air at constant pressure without a demand regulator. Compressed air was contained in a cylinder carried on the diver's chest in a harness, delivering air to the full face mask at a pressure controlled by a hand-operated regulator. Excess air, and the diver's exhaled breath, escaped by slightly lifting the edges of the mask.
The first diving club was created in France in 1935 by le Prieur and Jean Painleve, it was called the "club des scaphandres et de la vie sous l'eau", the club for divers and life under water. [5] [6] [7]
In 1946, Le Prieur invented a further improvement to his scuba set. Its fullface mask's front plate was loose in its seating and acted as a very big, and therefore very sensitive, diaphragm for a demand regulator: see Diving Regulator.
A scuba set, originally just scuba, is any breathing apparatus that is entirely carried by an underwater diver and provides the diver with breathing gas at the ambient pressure. Scuba is an anacronym for self-contained underwater breathing apparatus. Although strictly speaking the scuba set is only the diving equipment that is required for providing breathing gas to the diver, general usage includes the harness or rigging by which it is carried and those accessories which are integral parts of the harness and breathing apparatus assembly, such as a jacket or wing style buoyancy compensator and instruments mounted in a combined housing with the pressure gauge. In the looser sense, scuba set has been used to refer to all the diving equipment used by the scuba diver, though this would more commonly and accurately be termed scuba equipment or scuba gear. Scuba is overwhelmingly the most common underwater breathing system used by recreational divers and is also used in professional diving when it provides advantages, usually of mobility and range, over surface-supplied diving systems and is allowed by the relevant legislation and code of practice.
The timeline of underwater diving technology is a chronological list of notable events in the history of the development of underwater diving equipment. With the partial exception of breath-hold diving, the development of underwater diving capacity, scope, and popularity, has been closely linked to available technology, and the physiological constraints of the underwater environment.
Aqua-Lung was the first open-circuit, self-contained underwater breathing apparatus to achieve worldwide popularity and commercial success. This class of equipment is now commonly referred to as a twin-hose diving regulator, or demand valve. The Aqua-Lung was invented in France during the winter of 1942–1943 by two Frenchmen: engineer Émile Gagnan and Jacques Cousteau, who was a Naval Lieutenant. It allowed Cousteau and Gagnan to film and explore underwater more easily.
A rebreather is a breathing apparatus that absorbs the carbon dioxide of a user's exhaled breath to permit the rebreathing (recycling) of the substantially unused oxygen content, and unused inert content when present, of each breath. Oxygen is added to replenish the amount metabolised by the user. This differs from open-circuit breathing apparatus, where the exhaled gas is discharged directly into the environment. The purpose is to extend the breathing endurance of a limited gas supply, while also eliminating the bubbles otherwise produced by an open circuit system. The latter advantage over other systems is useful for covert military operations by frogmen, as well as for undisturbed observation of underwater wildlife. A rebreather is generally understood to be a portable apparatus carried by the user. The same technology on a vehicle or non-mobile installation is more likely to be referred to as a life-support system.
A diving regulator or underwater diving regulator is a pressure regulator that controls the pressure of breathing gas for underwater diving. The most commonly recognised application is to reduce pressurized breathing gas to ambient pressure and deliver it to the diver, but there are also other types of gas pressure regulator used for diving applications. The gas may be air or one of a variety of specially blended breathing gases. The gas may be supplied from a scuba cylinder carried by the diver, in which case it is called a scuba regulator, or via a hose from a compressor or high-pressure storage cylinders at the surface in surface-supplied diving. A gas pressure regulator has one or more valves in series which reduce pressure from the source, and use the downstream pressure as feedback to control the delivered pressure, or the upstream pressure as feedback to prevent excessive flow rates, lowering the pressure at each stage.
A full-face diving mask is a type of diving mask that seals the whole of the diver's face from the water and contains a mouthpiece, demand valve or constant flow gas supply that provides the diver with breathing gas. The full face mask has several functions: it lets the diver see clearly underwater, it provides the diver's face with some protection from cold and polluted water and from stings, such as from jellyfish or coral. It increases breathing security and provides a space for equipment that lets the diver communicate with the surface support team.
Scuba diving is a mode of underwater diving whereby divers use breathing equipment that is completely independent of a surface breathing gas supply, and therefore has a limited but variable endurance. The name scuba is an anacronym for "Self-Contained Underwater Breathing Apparatus" and was coined by Christian J. Lambertsen in a patent submitted in 1952. Scuba divers carry their own source of breathing gas, usually compressed air, affording them greater independence and movement than surface-supplied divers, and more time underwater than free divers. Although the use of compressed air is common, a gas blend with a higher oxygen content, known as enriched air or nitrox, has become popular due to the reduced nitrogen intake during long or repetitive dives. Also, breathing gas diluted with helium may be used to reduce the effects of nitrogen narcosis during deeper dives.
Porpoise is a tradename for scuba developed by Ted Eldred in Australia and made there from the late 1940s onwards. The first Porpoise was a closed circuit oxygen rebreather, and the following models were all single hose open circuit regulators.
In underwater diving, an alternative air source, or more generally alternative breathing gas source, is a secondary supply of air or other breathing gas for use by the diver in an emergency. Examples include an auxiliary demand valve, a pony bottle and bailout bottle.
Vintage scuba is scuba equipment dating from 1975 and earlier, and the practice of diving using such equipment.
The breathing performance of regulators is a measure of the ability of a breathing gas regulator to meet the demands placed on it at varying ambient pressures and temperatures, and under varying breathing loads, for the range of breathing gases it may be expected to deliver. Performance is an important factor in design and selection of breathing regulators for any application, but particularly for underwater diving, as the range of ambient operating pressures and temperatures, and variety of breathing gases is broader in this application. A diving regulator is a device that reduces the high pressure in a diving cylinder or surface supply hose to the same pressure as the diver's surroundings. It is desirable that breathing from a regulator requires low effort even when supplying large amounts of breathing gas as this is commonly the limiting factor for underwater exertion, and can be critical during diving emergencies. It is also preferable that the gas is delivered smoothly without any sudden changes in resistance while inhaling or exhaling, and that the regulator does not lock up and either fail to supply gas or free-flow. Although these factors may be judged subjectively, it is convenient to have standards by which the many different types and manufactures of regulators may be objectively compared.
Freeflow in underwater diving apparatus is a continuous flow of gas from a storage or supply unit. In scuba diving it is usually undesirable and considered a malfunction, while in surface supplied diving it may be a malfunction or a user selected option in demand systems, or the standard mode of operation in freeflow systems.
Maurice Fernez 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.
The history of underwater diving starts with freediving as a widespread means of hunting and gathering, both for food and other valuable resources such as pearls and coral. By classical Greek and Roman times commercial applications such as sponge diving and marine salvage were established. Military diving also has a long history, going back at least as far as the Peloponnesian War, with recreational and sporting applications being a recent development. Technological development in ambient pressure diving started with stone weights (skandalopetra) for fast descent. In the 16th and 17th centuries diving bells became functionally useful when a renewable supply of air could be provided to the diver at depth, and progressed to surface-supplied diving helmets—in effect miniature diving bells covering the diver's head and supplied with compressed air by manually operated pumps—which were improved by attaching a waterproof suit to the helmet and in the early 19th century became the standard diving dress.
The history of scuba diving is closely linked with the history of the equipment. By the turn of the twentieth century, two basic architectures for underwater breathing apparatus had been pioneered; open-circuit surface supplied equipment where the diver's exhaled gas is vented directly into the water, and closed-circuit breathing apparatus where the diver's carbon dioxide is filtered from the exhaled breathing gas, which is then recirculated, and more gas added to replenish the oxygen content. Closed circuit equipment was more easily adapted to scuba in the absence of reliable, portable, and economical high pressure gas storage vessels. By the mid-twentieth century, high pressure cylinders were available and two systems for scuba had emerged: open-circuit scuba where the diver's exhaled breath is vented directly into the water, and closed-circuit scuba where the carbon dioxide is removed from the diver's exhaled breath which has oxygen added and is recirculated. Oxygen rebreathers are severely depth limited due to oxygen toxicity risk, which increases with depth, and the available systems for mixed gas rebreathers were fairly bulky and designed for use with diving helmets. The first commercially practical scuba rebreather was designed and built by the diving engineer Henry Fleuss in 1878, while working for Siebe Gorman in London. His self contained breathing apparatus consisted of a rubber mask connected to a breathing bag, with an estimated 50–60% oxygen supplied from a copper tank and carbon dioxide scrubbed by passing it through a bundle of rope yarn soaked in a solution of caustic potash. During the 1930s and all through World War II, the British, Italians and Germans developed and extensively used oxygen rebreathers to equip the first frogmen. In the U.S. Major Christian J. Lambertsen invented a free-swimming oxygen rebreather. In 1952 he patented a modification of his apparatus, this time named SCUBA, an acronym for "self-contained underwater breathing apparatus," which became the generic English word for autonomous breathing equipment for diving, and later for the activity using the equipment. After World War II, military frogmen continued to use rebreathers since they do not make bubbles which would give away the presence of the divers. The high percentage of oxygen used by these early rebreather systems limited the depth at which they could be used due to the risk of convulsions caused by acute oxygen toxicity.
The following outline is provided as an overview of and topical guide to underwater diving:
The following index is provided as an overview of and topical guide to underwater diving:
The mechanism of diving regulators is the arrangement of components and function of gas pressure regulators used in the systems which supply breathing gases for underwater diving. Both free-flow and demand regulators use mechanical feedback of the downstream pressure to control the opening of a valve which controls gas flow from the upstream, high-pressure side, to the downstream, low-pressure side of each stage. Flow capacity must be sufficient to allow the downstream pressure to be maintained at maximum demand, and sensitivity must be appropriate to deliver maximum required flow rate with a small variation in downstream pressure, and for a large variation in supply pressure, without instability of flow. Open circuit scuba regulators must also deliver against a variable ambient pressure. They must be robust and reliable, as they are life-support equipment which must function in the relatively hostile seawater environment, and the human interface must be comfortable over periods of several hours.
Jarry, Maud (September 2003). "La bataille des saucisses: les fusées d'Yves Le Prieur en 1916" [The Battle of the Sausages: Yves Le Prieur's Rockets in 1916]. Le Fana de l'Aviation (in French) (406): 28–35. ISSN 0757-4169.
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