In general usage they are often manifolded together and managed as a unit.
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Manifolded twin 12l steel cylinders with isolation valve A manifolded twin set with isolation valve is a special case. It is a redundant air supply when the isolation valve is closed, as the cylinders are then for most practical purposes independent, but not when it is open, as a leak will eventually drain both cylinders. Divers who intend to rely on a manifolded twin for bailout need to be able to isolate the cylinders quickly, as a major leak can drain a set in quite a short time. In comparison with independent twins, the manifolded set is less task loading through the most of the dive, but requires skilled and immediate reaction in the event of a catastrophic failure, as it does not fail safe.
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Manifolded twin and triple cylinder sets have been used since the days of Cousteau and Gagnan's development of the open circuit regulator, as can be seen from early photographs of the equipment. These were downstream manifolds, which connected the cylinders together by linking the outlets of the cylinder valves, and had one outlet for a regulator. This arrangement allowed larger gas storage capacity using the limited range of cylinders available. Independent valving of the manifolded cylinders also allowed the gas supply to be monitored in the absence of submersible pressure gauges, by opening and closing the valves in a specific order, as the gas was used up.
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Systems sold directly to the arenas. US Sound Touring Sound System for The Judds/Wynonna Judd : First “Coherent Zone” sound system design including first high- directivity mid/high, 18” bass system and very low-profile stage monitor for improved visual qualities. Electro Voice MT™ Manifold Technology sound reinforcement system: Basic research and invention leading to this breakthrough, multiple manifolded-driver product design.
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These components are still mainstays of the engineered sound product line. Bose Corporation Panaray LT family: Design of core arraying loudspeaker family for high-end large-venue sound including invention and engineering of “V4” manifolded midrange driver. Bose Corporation sound system for the Holy Mosque, Mecca : Designed a unique horn-waveguide system for this acoustically-challenging, aesthetically-demanding all-marble facility.
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Cylinder bands are straps, usually of stainless steel, which are used to clamp two cylinders together as a twin set. The cylinders may be manifolded or independent. It is usual to use a cylinder band near the top of the cylinder, just below the shoulders, and one lower down. The conventional distance between centrelines for bolting to a backplate is .
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Multiple-tank configurations include downstream manifolded twins, with a single regulator, independent or separate doubles which are two cylinders clamped to a backplate, but without a manifold, side mount cylinders, or upstream manifolded twins, with two complete regulator sets, which may have an isolation valve. The function of a manifold is to connect the gas supplies of two back mounted cylinders (called doubles or twins), allowing the diver to breathe simultaneously from both. The manifold is a metal tube which is connected to the cylinder valves or directly to the cylinders, and may include an isolation valve or an outlet to connect a scuba regulator. On an upstream manifold the left and right cylinder valves allow the corresponding first stage regulator to be shut off, leaving the entire gas supply to be used through the remaining regulator.
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Many times, the machine producing the dust will have a port to which a duct can be directly attached. Second, the dust must be conveyed. This is done via a ducting system, properly sized and manifolded to maintain a consistent minimum air velocity required to keep the dust in suspension for conveyance to the collection device. A duct of the wrong size can lead to material settling in the duct system and clogging it.
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Also known as a manifold cage or regulator cage, this is a structure which can be clamped to the neck of the cylinder or manifolded cylinders to protect the valves and regulator first stages from impact and abrasion damage while in use and from rolling the valve closed by friction of the handwheel against an overhead. A valve cage is often made of stainless steel, and some designs can snag on obstructions.
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Another aspect of scuba configuration is how the primary cylinders are carried by the diver. The two basic arrangements are back mount and side mount. Back mount is the system where one or more cylinders are firmly attached to a harness, usually with a buoyancy compensator jacket or wing, and carried on the diver's back. Back mount allows cylinders to be manifolded together as twins, or for special circumstances, trips or quads.
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Scuba divers may dive with a single cylinder, a pair of similar cylinders, or a main cylinder and a smaller "pony" cylinder, carried on the diver's back or clipped onto the harness at the sides. Paired cylinders may be manifolded together or independent. In some cases, more than two cylinders are needed. When pressurised, a cylinder carries an equivalent volume of free gas greater than its water capacity, because the gas is compressed up to several hundred times atmospheric pressure.
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Sidemount diving offers some benefits in the flexibility of equipment. Cylinders suitable for sidemount diving are usually freely available for rental, unlike manifolded twin sets for back-mounted use, which allows the traveller to conduct technical or overhead environment dives without having to source twin cylinder sets. When diving in remote locations, the transportation of single diving cylinders, especially by hand, may be less physically taxing. Sidemount harness can be lighter and less bulky than back-mounted alternatives – allowing for easier and cheaper air travel.
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Mixed breathing gases are provided from high pressure bulk storage systems for saturation diving, but these are less portable, and generally involve manifolded racks of cylinders of approximately 50 litres water capacity arranged as quads and even larger racks of high pressure tubes. If gas reclaim systems are used, the reclaimed gas is scrubbed of carbon dioxide, filtered of other contaminants, and recompressed into high pressure cylinders for interim storage, ans is generally blended with oxygen or helium to make up the required mix for the next dive before re-use.
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The RB80 is usually carried between a set of back mounted isolation manifolded double cylinders, supported on a backplate and wing harness. Dives in shallow open water could be done using a small single tank mounted to one side of the RB80. It can also be side-mounted for tight restrictions. Occasionally extreme dive profiles require the use of a rebreather for bailout, and the RB80 can be carried as a back mounted pair, as one back mount and one side mount, or both side mounted for those occasions.
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Face sealed manifolded twin 12l steel cylinder set A scuba manifold is used to connect two diving cylinders containing breathing gas, providing a greater amount of gas for longer dive times or deeper dives. An isolation manifold allows the connection between the cylinders to be closed in the case of a leak from one of the cylinders or its valve or regulator, conserving the gas in the other cylinder. Diving with two or more cylinders is often associated with technical diving. Several configurations are used, each with its own range of applications, advantages and disadvantages.
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Early scuba sets were simply a set of harness straps connected to a cylinder or manifolded group of cylinders, with a regulator connected to the cylinder valve. This works quite satisfactorily for twin and triple sets, which are inherently quite stable on the back, and have little tendency to roll from side to side. A simple backplate solved the rolling problem, and was often developed into a more ergonomically formed metal, fibreglass, or later, blow- moulded plastic backplate. These usually used simple webbing harness, and were cheap, reliable, and easily repaired.
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Photos gas cabinet inventory The major industrial gases can be produced in bulk and delivered to customers by pipeline, but can also be packaged and transported. Most gases are sold in gas cylinders and some sold as liquid in appropriate containers (e.g. Dewars) or as bulk liquid delivered by truck. The industry originally supplied gases in cylinders to avoid the need for local gas generation; but for large customers such as steelworks or oil refineries, a large gas production plant may be built nearby (typically called an "on-site" facility) to avoid using large numbers of cylinders manifolded together.
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Technical divers have generally used a redundant gas supply system, either isolation-manifolded or independent back-mounted cylinders. Recreational divers have traditionally resorted to using buddy supplied gas, or relatively small bailout ‘pony cylinders’ or ‘ascent bottles’ for out-of-air emergencies. Whether attached to the primary cylinder, or slung at the chest, these cylinders often present problems with stability and streamlining, whilst not always providing more than a bare minimum supply of air for emergency ascent. Sidemount diving with two equal-sized cylinders helps resolve stability and streamlining issues, and can ensure that an adequate redundant reserve of air is maintained, similar to back-mounted twins.
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It is possible to accidentally turn off an isolation valve during a fill or a safety drill, and a closed isolator can cause problems. The isolator is normally left completely open, so the manifolded cylinders maintain equal pressure during filling and use, and are closed during an emergency to prevent gas loss from both cylinders, during safety drills, or to identify a fault. Symptoms of a closed isolator depend on which tank the diver is breathing from. If the gauge is on the same tank that the diver is breathing from, the diver may notice an unusually quick reduction in pressure, and mistakenly believe that they are running out of gas.
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Savarkar's Bande Mataram contained exhortations [advocating terrorism] ... This sort of propaganda produced a natural effect. A. M. T. Jackson, the Magistrate ... was shot dead on 21 December 1909 ... charges against him [Savarkar] included the sending of pistols and seditious pamphlets to India. Another charge was that in 1908 he with the help of residents in the India House manifolded in type a number of copies of a work describing minutely the manner of preparing explosives and bombs. He despatched these copies to various addresses in India. One of the two charges against Savarkar during his trial in Bombay was for abetting the murder of the District Magistrate of Nasik, A.M.T. Jackson, by Anant Kanhere in December 1909.
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The commonly used configurations for multiple cylinders are to either carry the bottom gas in back-mounted cylinders of sufficient total volume, either manifolded or independent, and the other mixes in sling-mounts clipped off to the sides of the diver's harness on D-rings, or to carry all gases in side-mounted cylinders. Decompression gas, when different from the gas used for the main part of the dive, is commonly carried in one or more cylinders suspended from the side of the diver's harness by clips. Multiple cylinders may be carried this way for extreme dives. Sidemount harnesses require the cylinders to be carried individually clipped to the harness at the sides of the diver.
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J-valves fell out of favor with the introduction of pressure gauges, which allow divers to keep track of their air underwater, especially as the valve-type is vulnerable to accidental release of reserve air and increases the cost and servicing of the valve. J-valves are occasionally still used when work is done in visibility so poor that the pressure gauge cannot be seen, even with a light. Most side-spindled valves are right handed, meaning that the knob is on the diver's right hand side, but left handed valves are also produced for manifolded sets and other applications where it is more convenient. Axial spindle valves are also available where the spindle lies on the axis of the thread which connects the valve to the cylinder, with the knob on top.
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Helium Quad - Breathing gas storage asset Gas storage and blending equipment are provided to pressurize and flush the system, and treatment gases should be available appropriate to the planned storage depths. Bulk stock of premixed gas is usually provided to suit the planned depth of the operation, and separate bulk stock of helium and oxygen to make up additional requirements, adjust chamber gas composition as the oxygen is used up, and mix decompression gas. Bulk gas is usually stored in manifolded groups of storage cylinders known as "quads", which usually carry about 16 high pressure cylinders, each of about 50 litres internal volume mounted on a frame for ease of transport, or larger frames carrying larger capacity high pressure "tubes". These tube frames are usually designed to be handled by intermodal container handling equipment, so are usually made in one of the standard sizes for intermodal containers.
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These include a secondary regulator on a manifolded twin set without isolation valve, a secondary regulator on a double cylinder valve on a single cylinder, an auxiliary second stage on a single regulator (octopus regulator), and the pneumofathometer line for surface supplied divers. The use of two independent regulators on independent cylinder valves supplied from the same cylinder is a system most applicable to cold-water diving, where a regulator can ice up and free flow, so the diver needs to be able to close the cylinder valve for that regulator, and fall back on a second regulator. The pneumofathometer line on a surface supplied umbilical is a valuable backup supply in case of damage to the main supply hose, or if a diver needs to supply air to another diver on surface supply, as the usual configurations of helmet and full face mask do not allow buddy breathing of the conventional kind. The Pneumo line can be tucked into the neck dam or under the skirt of a full face mask, and provided the helmet or mask is not leaking heavily, will supply adequate air for an assisted ascent.
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