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83-656: 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,

166-503: A constant mass flow of fresh gas to an active type semi-closed rebreather to replenish the gas used by the diver and to maintain an approximately constant composition of the loop mix. Two main types are used: the fixed orifice and the adjustable orifice (usually a needle valve). The constant mass flow valve is usually supplied by a gas regulator that is isolated from the ambient pressure so that it provides an absolute pressure regulated output (not compensated for ambient pressure). This limits

249-513: A hyperbaric chamber , though those gases are generally not reclaimed. A diverter valve is provided to allow the diver to manually switch to open circuit if the reclaim valve malfunctions, and an underpressure flood valve allows water to enter the helmet to avoid a squeeze if the reclaim valve fails suddenly, allowing the diver time to switch to open circuit without injury. Reclaim valves for deep diving may use two stages to give smoother flow and lower work of breathing . The reclaim regulator works on

332-533: A mining engineer from Espalion (France), Benoît Rouquayrol , invented a demand valve with an iron air reservoir to let miners breathe in flooded mines. He called his invention régulateur ('regulator'). In 1864 Rouquayrol met the French Imperial Navy officer Auguste Denayrouze and they worked together to adapt Rouquayrol's regulator to diving. The Rouquayrol-Denayrouze apparatus was mass-produced with some interruptions from 1864 to 1965. As of 1865 it

415-457: 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

498-413: A 5-thread DIN valve socket, are rated for 232/240 bar, and can only be used with valves which are designed to accept them. These can be recognised by a dimple recess opposite to the outlet opening, used to locate the screw of an A-clamp. Block adaptors are generally rated for 200 bar, and can be used with almost any 200 bar 5-thread DIN valve. A-clamp or yoke adaptors comprise a yoke clamp with

581-406: A DIN socket in line. They are slightly more vulnerable to O-ring extrusion than integral yoke clamps, due to greater leverage on the first stage regulator. Most contemporary diving regulators are single-hose two-stage demand regulators. They consist of a first-stage regulator and a second-stage demand valve connected by a low pressure hose to transfer breathing gas, and allow relative movement within

664-406: A back-pressure regulator. When an externally vented BIBS is used at low chamber pressure, a vacuum assist may be necessary to keep the exhalation backpressure down to provide an acceptable work of breathing . The major application for this type of BIBS is supply of breathing gas with a different composition to the chamber atmosphere to occupants of a hyperbaric chamber where the chamber atmosphere

747-465: A black belt the student also begins to instruct, and may be referred to as a senpai (senior student) or sensei (teacher). In others, a black belt student should not be called sensei until they are Sandan (third-degree black belt), or the titles kyosa or sabom in Korean martial arts as a second degree or higher, as this denotes a greater degree of experience and a sensei must have this and grasp of what

830-501: A constant pressure difference between the interstage pressure and the ambient pressure even as the tank pressure drops with consumption. The balanced regulator design allows the first stage orifice to be as large as needed without incurring performance degradation as a result of changing tank pressure. The first stage regulator body generally has several low-pressure outlets (ports) for second-stage regulators and BCD and dry suit inflators, and one or more high-pressure outlets, which allow

913-458: A demand valve which works on the same principles as a regular diving demand valve second stage. Like any other breathing apparatus, the dead space must be limited to minimise carbon dioxide buildup in the mask. In some cases the outlet suction must be limited and a back-pressure regulator may be required. This would usually be the case for use in a saturation system. Use for oxygen therapy and surface decompression on oxygen would not generally need

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996-534: 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

1079-492: A different connection type. CGA 850 Yoke connectors (sometimes called A-clamps from their shape) are the most popular regulator connection in North America and several other countries. They clamp the high pressure inlet opening of the regulator against the outlet opening of the cylinder valve, and are sealed by an O-ring in a groove in the contact face of the cylinder valve. The user screws the clamp in place finger-tight to hold

1162-543: A different kind of regulator to control the flow of exhaled gas to the return hose and through the topside reclaim system, or to the outside of the hyperbaric chamber, these are of the back-pressure regulator class. The performance of a regulator is measured by the cracking pressure and added mechanical work of breathing , and the capacity to deliver breathing gas at peak inspiratory flow rate at high ambient pressures without excessive pressure drop, and without excessive dead space . For some cold water diving applications

1245-524: A diving demand valve supplied with air from two gas cylinders through a full-face mask . Commeinhes died in 1944 during the liberation of Strasbourg and his invention was soon forgotten. The Commeinhes demand valve was an adaptation of the Rouquayoul-Denayrouze mechanism, not as compact as was the Cousteau-Gagnan apparatus. It was not until December 1942 that the demand valve was developed to

1328-441: A major loss of breathing gas. This can be a serious problem if it happens when the diver is at depth. Yoke fittings are rated up to a maximum of 240 bar working pressure. The DIN fitting is a type of screw-in connection to the cylinder valve. The DIN system is less common worldwide, but has the advantage of withstanding greater pressure, up to 300 bar, allowing use of high-pressure steel cylinders. They are less susceptible to blowing

1411-548: A positive pressure regulator (a regulator that maintains a pressure inside the mouthpiece, mask or helmet, which is slightly greater than the ambient pressure). Once the valve has opened, gas flow should continue at the smallest stable pressure difference reasonably practicable while the diver inhales, and should stop as soon as gas flow stops. Several mechanisms have been devised to provide this function, some of them extremely simple and robust, and others somewhat more complex, but more sensitive to small pressure changes. The diaphragm

1494-493: 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. In 1946, Le Prieur invented a further improvement to his scuba set. Its fullface mask 's front plate

1577-419: A reclaim regulator, which ensures that gas pressure in the helmet cannot fall below the ambient pressure. The gas is processed at the surface in the helium reclaim system by filtering, scrubbing and boosting into storage cylinders until needed. The oxygen content may be adjusted when appropriate. The same principle is used in built-in breathing systems used to vent oxygen-rich treatment gases from

1660-449: A scuba diver from a scuba cylinder, while a diving helmet demand valve may supply gas from surface supply or a bailout scuba cylinder. A demand valve detects the pressure drop when the diver starts inhaling and supplies the diver with a breath of gas at ambient pressure. When the diver stops inhaling, the demand valve closes to stop the flow. The demand valve has a chamber, which in normal use contains breathing gas at ambient pressure, which

1743-494: 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 . 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

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1826-414: A similar principle to the demand regulator, in that it allows flow only when the pressure difference between the interior of the helmet and the ambient water opens the valve, but uses the upstream over-pressure to activate the valve, where the demand valve uses downstream underpressure. Reclaim regulators are also sometimes used for hazmat diving to reduce the risk of backflow of contaminated water through

1909-456: A sixth dan will wear a red-and-white belt. The red-and-white belt is often reserved only for ceremonial occasions, and a regular black belt is still worn during training. At 9th or 10th dan some schools award red . In some schools of jujutsu , the shihan rank and higher wear purple belts. These other colors are often still referred to collectively as "black belts". Demand regulator A diving regulator or underwater diving regulator

1992-485: A submersible pressure gauge (SPG), gas-integrated diving computer or remote pressure tranducer to read the cylinder pressure. One low-pressure port with a larger bore may be designated for the primary second stage as it will give a higher flow at maximum demand for lower work of breathing. The mechanism inside the first stage can be of the diaphragm or piston type, and can be balanced or unbalanced. Unbalanced regulators produce an interstage pressure which varies slightly as

2075-418: 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

2158-553: Is based on the oxygen system used by pilots. Other early single-hose regulators developed during the 1950s include Rose Aviation's "Little Rose Pro," the "Nemrod Snark" (from Spain), and the Sportsways "Waterlung," designed by diving pioneer Sam LeCocq in 1958. In France, in 1955, a patent was taken out by Bronnec & Gauthier for a single hose regulator, later produced as the Cristal Explorer. The "Waterlung" would eventually become

2241-498: Is commonly more rigorous and more centralised than for lower grades. In contrast to the "black belt as master" stereotype, a black belt commonly indicates the wearer is competent in a style's basic technique and principles. Another way to describe this links to the terms used in Japanese arts; shodan (for a first degree black belt), means literally the first/beginning step, and the next grades, nidan and sandan are each numbered as ni

2324-419: Is connected to a bite-grip mouthpiece, a full-face mask , or a diving helmet , either direct coupled or connected by a flexible low-pressure hose. On one side of the chamber is a flexible diaphragm to sense the pressure difference between the gas in the chamber on one side and the surrounding water on the other side, and control the operation of the valve which supplies pressurised gas into the chamber. This

2407-536: Is controlled, and contamination by the BIBS gas would be a problem. This is common in therapeutic decompression, and hyperbaric oxygen therapy, where a higher partial pressure of oxygen in the chamber would constitute an unacceptable fire hazard, and would require frequent ventilation of the chamber to keep the partial pressure within acceptable limits. Frequent ventilation is noisy and expensive, but can be used in an emergency. Rebreather systems used for diving recycle most of

2490-445: Is done by a mechanical system linking the diaphragm to a valve which is opened to an extent proportional to the displacement of the diaphragm from the closed position. The pressure difference between the inside of the mouthpiece and the ambient pressure outside the diaphragm required to open the valve is known as the cracking pressure. This cracking pressure difference is usually negative relative to ambient, but may be slightly positive on

2573-524: Is involved in teaching a martial art. In Japanese martial arts the further subdivisions of black belt ranks may be linked to dan grades and indicated by 'stripes' on the belt. Yūdansha (roughly translating from Japanese to "person who holds a dan grade") is often used to describe those who hold a black belt rank. While the belt remains black, stripes or other insignia may be added to denote seniority, in some arts, very senior grades will wear differently colored belts. In judo and some forms of karate ,

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2656-405: Is protected by a cover with holes or slits through which outside water can enter freely. This cover reduces sensitivity of the diaphragm to water turbulence and dynamic pressure due to movement, which might otherwise trigger gas flow when it is not needed. When the diver starts to inhale, the removal of gas from the casing lowers the pressure inside the chamber, and the external water pressure moves

2739-421: Is two and san is three, meaning second step, third step, etc. As a "black belt" is commonly viewed as conferring some status, achieving one has been used as a marketing gimmick. For example, a school might guarantee that one will be awarded within a certain period, or for a certain amount of money. Such schools are sometimes referred to as McDojos or belt factories. In some Japanese schools, after obtaining

2822-466: The black belt is associated with expertise, but may indicate only competence, depending on the martial art. The use of colored belts is a relatively recent invention dating from the 1880s. The systematic use of belt colour to denote rank was first used in Japan by Jigoro Kano , the founder of judo in the 1880s. Previously, Japanese Koryu instructors tended to provide rank certificates only. Initially

2905-417: 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

2988-451: The O-ring seal if banged against something while in use. DIN fittings are the standard in much of Europe and are available in most countries. The DIN fitting is considered more secure and therefore safer by many technical divers . It is more compact than the yoke fitting and less exposed to impact with an overhead. Several manufacturers market an otherwise identical first stage varying only in

3071-455: The bailout demand valve in order to bail out onto open circuit. Although costly, this reduction in critical steps makes the integrated BOV a significant safety advantage, particularly when there is a high partial pressure of carbon dioxide in the loop, as hypercapnia can make it difficult or impossible for the diver to hold their breath even for the short period required to swap mouthpieces. Constant mass flow addition valves are used to supply

3154-415: The breathing gas, but are not based on a demand valve system for their primary function. Instead, the breathing loop is carried by the diver and remains at ambient pressure while in use. Regulators may be used in scuba rebreathers to make up a deficit in loop gas volume, and to provide oxygen-rich gas to compensate for metabolic use. The automatic diluent valve (ADV) is used in a rebreather to add gas to

3237-500: The breathing loop. It can be isolated while the diver is using the rebreather to recycle breathing gas, and opened, while at the same time isolating the breathing loop, when a problem causes the diver to bail out onto open circuit. The main distinguishing feature of the BOV is that the same mouthpiece is used for open and closed-circuit, and the diver does not have to shut the dive/surface valve (DSV), remove it from their mouth, and find and insert

3320-419: The capacity to deliver high flow rates at low ambient temperatures without jamming due to regulator freezing is important. The diving regulator is a mechanism which reduces the pressure of the supply of breathing gas and provides it to the diver at approximately ambient pressure. The gas may be supplied on demand, when the diver inhales, or as a constant flow past the diver inside the helmet or mask, from which

3403-646: The choice of cylinder valve connection. In these cases it may be possible to buy original components to convert yoke to DIN and vice versa. The complexity of the conversion may vary, and parts are not usually interchangeable between manufacturers. The conversion of Apeks regulators is particularly simple and only requires an Allen key and a ring spanner . Adaptors are available to allow connection of DIN regulators to yoke cylinder valves (A-clamp or yoke adaptor), and to connect yoke regulators to DIN cylinder valves. There are two types of adaptors for DIN valves: plug adaptors and block adaptors. Plug adaptors are screwed into

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3486-425: The constraints of hose length and flexibility. The first stage is mounted to the cylinder valve or manifold via one of the standard connectors (Yoke or DIN), and reduces cylinder pressure to an intermediate pressure, usually about 8 to 11 bars (120 to 160 psi) higher than the ambient pressure, also called interstage pressure, medium pressure or low pressure. A balanced regulator first stage automatically keeps

3569-405: The cylinder pressure changes and to limit this variation the high-pressure orifice size is small, which decreases the maximum capacity of the regulator. A balanced regulator maintains a constant interstage pressure difference for all cylinder pressures. The second stage, or demand valve reduces the pressure of the interstage air supply to ambient pressure on demand from the diver. The operation of

3652-547: The depth range in which constant mass flow is possible through the orifice, but provides a relatively predictable gas mixture in the breathing loop. An over-pressure relief valve in the first stage is used to protect the output hose. Unlike most other diving gas supply regulators, constant mass flow orifices do not control the downstream pressure, but they do regulate the flow rate. Manual and electronically controlled addition valves are used on manual and electronically controlled closed circuit rebreathers (mCCR, eCCR) to add oxygen to

3735-405: The diaphragm inwards operating a lever which lifts the valve off its seat, releasing gas into the chamber. The inter-stage gas, at about 8 to 10 bars (120 to 150 psi) over ambient pressure, expands through the valve orifice as its pressure is reduced to ambient and supplies the diver with more gas to breathe. When the diver stops inhaling the chamber fills until the external pressure is balanced,

3818-519: The diaphragm returns to its rest position and the lever releases the valve to be closed by the valve spring and gas flow stops. When the diver exhales, one-way valves made from a flexible air-tight material flex outwards under the pressure of the exhalation, letting gas escape from the chamber. They close, making a seal, when the exhalation stops and the pressure inside the chamber reduces to ambient pressure. The vast majority of demand valves are used on open circuit breathing apparatus, which means that

3901-407: The diver inhales, a free flow regulator provides a constant flow rate at the delivery pressure, reclaim and built-in-breathing-systems regulators allow exhaust outflow only during exhalation. Rebreathers use demand regulators to make up a volume deficit in the loop, and may use constant mass flow regulators to refresh the oxygen content of the loop gas mixture. A scuba diving regulator is used to supply

3984-450: The diver uses what is necessary, while the remainder goes to waste. The gas may be provided directly to the diver, or to a rebreather circuit, to make up for used gas and volume changes due to depth variations. Gas supply may be from a high-pressure scuba cylinder carried by the diver, or from a surface supply through a hose connected to a compressor or high pressure storage system. An open circuit demand valve provides gas flow only while

4067-610: The diver. These are the earliest type of breathing set flow control. The diver must physically open and close the adjustable supply valve to regulate flow. Constant flow valves in an open circuit breathing set consume gas less economically than demand valve regulators because gas flows even when it is not needed, and must flow at the rate required for peak inhalation. Before 1939, self contained diving and industrial open circuit breathing sets with constant-flow regulators were designed by Le Prieur , but did not get into general use due to very short dive duration. Design complications resulted from

4150-403: 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. 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

4233-491: The downstream pressure which is limited by the ambient pressure of the exhaust and the flow resistance of the delivery system (mainly the umbilical and exhaust valve) and not much influenced by the breathing of the diver. Diving rebreather systems may also use regulators to control the flow of fresh gas, and demand valves, known as automatic diluent valves , to maintain the volume in the breathing loop during descent. Gas reclaim systems and built-in breathing systems (BIBS) use

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4316-424: The exhaled gas is discharged into the surrounding environment and lost. Reclaim valves can be fitted to helmets to allow the used gas to be returned to the surface for reuse after removing the carbon dioxide and making up the oxygen. This process, referred to as "push-pull", is technologically complex and expensive and is only used for deep commercial diving on heliox mixtures, where the saving on helium compensates for

4399-403: The exhaust hose, the spring returns this valve to the closed position, cutting off further flow, and conserving the chamber atmosphere. A negative or zero pressure difference over the exhaust diaphragm will keep it closed. The exhaust diaphragm is exposed to the chamber pressure on one side, and exhaled gas pressure in the oro-nasal mask on the other side. The supply of gas for inhalation is through

4482-448: The exhaust valve is provided by the loop overpressure valve. Some passive semi-closed circuit rebreathers use the ADV to add gas to the loop to compensate for a portion of the gas discharged automatically during the breathing cycle as a way of maintaining a suitable oxygen concentration. The bailout valve (BOV) is an open circuit demand valve built into a rebreather mouthpiece or other part of

4565-407: The exhaust valves into the helmet. In this application there would not be an underpressure flood valve, but the pressure differences and the squeeze risk are relatively low. The breathing gas in this application would usually be air and would not actually be recycled. BIBS regulators for hyperbaric chambers have a two-stage system at the diver similar to reclaim helmets, though for this application

4648-402: The expense and complications of the system, and for diving in contaminated water, where the gas is not reclaimed, but the system reduces the risk of contaminated water leaking into the helmet through an exhaust valve. These are generally used in surface supply diving with free-flow masks and helmets. They are usually a large high-flow rated industrial gas regulator that is manually controlled at

4731-438: The first single-hose regulator to be widely adopted by the diving public. Over time, the convenience and performance of improved single hose regulators would make them the industry standard. Performance still continues to be improved by small increments, and adaptations have been applied to rebreather technology. The single hose regulator was later adapted for surface supplied diving in lightweight helmets and full-face masks in

4814-444: The first stage. In 1994 a reclaim system was developed in a joint project by Kirby-Morgan and Divex to recover expensive helium mixes during deep operations. 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

4897-412: The flow must be controlled so that only exhaled gas is vented through the system, and it does not drain the contents of the chamber to the outside. This is achieved by using a controlled exhaust valve which opens when a slight over-pressure relative to the chamber pressure on the exhaust diaphragm moves the valve mechanism against a spring. When this over-pressure is dissipated by the gas flowing out through

4980-529: The form which gained widespread acceptance. This came about after French naval officer Jacques-Yves Cousteau and engineer Émile Gagnan met for the first time in Paris . Gagnan, employed at Air Liquide , had miniaturized and adapted a Rouquayrol-Denayrouze regulator used for gas generators following severe fuel restrictions due to the German occupation of France ; Cousteau suggested it be adapted for diving, which in 1864

5063-423: The full-face mask or helmet. In twin-hose regulators the demand valve is included in the body of the regulator which is usually attached directly to the cylinder valve or manifold outlet, with a remote mouthpiece supplied at ambient pressure. A pressure-reduction regulator is used to control the delivery pressure of the gas supplied to a free-flow helmet or full-face mask, in which the flow is continuous, to maintain

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5146-465: The gas flow from the diving cylinder to its final use. The first-stage of the scuba regulator will usually be connected to the cylinder valve by one of two standard types of fittings. The CGA 850 connector, also known as an international connector, which uses a yoke clamp, or a DIN screw fitting. There are also European standards for scuba regulator connectors for gases other than air , and adapters to allow use of regulators with cylinder valves of

5229-414: The gas panel on the surface to the pressure required to provide the desired flow rate to the diver. Free flow is not normally used on scuba equipment as the high gas flow rates are inefficient and wasteful. In constant-flow regulators the pressure regulator provides a constant reduced pressure, which provides gas flow to the diver, which may be to some extent controlled by an adjustable orifice controlled by

5312-420: The glass close to their ear, the glass forming a microphone. In 1934 Le Prieur was granted French patent 768083 for an improved hand-controlled self-contained underwater breathing apparatus with full face mask. 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

5395-466: The glider's main wing. The first flight covered 200 m at an altitude of 10 m. 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)

5478-438: 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

5561-510: The loop to compensate automatically for volume reduction due to pressure increase with greater depth or to make up gas lost from the system by the diver exhaling through the nose while clearing the mask or as a method of flushing the loop . They are often provided with a purge button to allow manual flushing of the loop. The ADV is similar in concept and function to the open circuit demand valve and may use many similar components, but does not have an integral exhaust valve. An equivalent function to

5644-440: The loop to maintain oxygen partial pressure set-point. A manually or electronically controlled valve is used to release oxygen from the outlet of a standard scuba regulator first stage into the breathing loop. An over-pressure relief valve on the first stage is necessary to protect the hose in case of first stage leaks. Strictly speaking, these are not pressure regulators, they are flow control valves. The first recorded demand valve

5727-537: The metal surfaces of cylinder valve and regulator first stage in contact, compressing the o-ring between the radial faces of valve and regulator. When the valve is opened, gas pressure presses the O-ring against the outer cylindrical surface of the groove, completing the seal. The diver must take care not to screw the yoke down too tightly, or it may prove impossible to remove without tools. Conversely, failing to tighten sufficiently can lead to O-ring extrusion under pressure and

5810-424: The need to put the second-stage flow control valve where it could be easily operated by the diver. The cost of breathing gas containing a high fraction of helium is a significant part of the cost of deep diving operations , and can be reduced by recovering the breathing gas for recycling. A reclaim helmet is provided with a return line in the diver's umbilical , and exhaled gas is discharged to this hose through

5893-406: The outlet regulator dumps the exhaled gas through an outlet hose to the atmosphere outside the chamber. These are systems used to supply breathing gas on demand in a chamber which is at a pressure greater than the ambient pressure outside the chamber. The pressure difference between chamber and external ambient pressure makes it possible to exhaust the exhaled gas to the external environment, but

5976-399: The pressure at each stage. The terms "regulator" and "demand valve" (DV) are often used interchangeably, but a demand valve is the final stage pressure-reduction regulator that delivers gas only while the diver is inhaling and reduces the gas pressure to approximately ambient. In single-hose demand regulators, the demand valve is either held in the diver's mouth by a mouthpiece or attached to

6059-428: The relatively hostile seawater environment. Diving regulators use mechanically operated valves. In most cases there is ambient pressure feedback to both first and second stage, except where this is avoided to allow constant mass flow through an orifice in a rebreather, which requires a constant upstream pressure. The parts of a regulator are described here as the major functional groups in downstream order as following

6142-612: The tradition of the Rouquayrol-Denayrouze equipment to economise on gas usage. By 1969 Kirby-Morgan had developed a full-face mask - the KMB-8 Bandmask - using a single hose regulator. This was developed into the Kirby-Morgan SuperLite-17B by 1976, making use of the neck dam seal invented by Joe Savoie . Secondary (octopus) demand valves, submersible pressure gauges and low pressure inflator hoses were added to

6225-575: The wide obi was used. As practitioners trained in a kimono , only white and black obi were used. This kind of ranking is less common in arts that do not claim a far Eastern origin, though it is used in the Marine Corps Martial Arts Program . Rank and belts are not equivalent between arts, styles, or even within some organisations. In some arts, a black belt may be awarded in three years or even less, while in others it takes dedicated training of ten years or more. Testing for black belt

6308-447: Was invented in 1838 in France and forgotten in the next few years; another workable demand valve was not invented until 1860. On 14 November 1838, Dr. Manuel Théodore Guillaumet of Argentan, Normandy, France, filed a patent for a twin-hose demand regulator; the diver was provided air through pipes from the surface to a back mounted demand valve and from there to a mouthpiece. The exhaled gas

6391-633: 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

6474-505: Was acquired as a standard by the French Imperial Navy, but never was entirely accepted by the French divers because of a lack of safety and autonomy. In 1926 Maurice Fernez and Yves Le Prieur patented a hand-controlled constant flow regulator (not a demand valve), which used a full-face mask (the air escaping from the mask at constant flow ). In 1937 and 1942 the French inventor, Georges Commeinhes from Alsace , patented

6557-494: Was its original purpose. The single hose regulator, with a mouth held demand valve supplied with low pressure gas from the cylinder valve mounted first stage, was invented by Australian Ted Eldred in the early 1950s in response to patent restrictions and stock shortages of the Cousteau-Gagnan apparatus in Australia. In 1951 E. R. Cross invented the "Sport Diver," one of the first American-made single-hose regulators. Cross' version

6640-571: Was loose in its seating and acted as a very big, and therefore very sensitive, diaphragm for a demand regulator: see Diving Regulator . 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 . Black belt (martial arts) In East Asian martial arts ,

6723-699: 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

6806-553: 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. 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

6889-534: Was vented to the side of the head through a second hose. The apparatus was demonstrated to and investigated by a committee of the French Academy of Sciences: On 19 June 1838, in London, William Edward Newton filed a patent (no. 7695: "Diving apparatus") for a diaphragm-actuated, twin-hose demand valve for divers. However, it is believed that Mr. Newton was merely filing a patent on behalf of Dr. Guillaumet. In 1860

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