Nitrox refers to any gas mixture composed of nitrogen and oxygen. This includes atmospheric air, which is approximately 78% nitrogen, 21% oxygen, and 1% other gases, primarily argon. In the usual application, underwater diving, nitrox is normally distinguished from air and handled differently. The most common use of nitrox mixtures containing oxygen in higher proportions than atmospheric air is in scuba diving, where the reduced partial pressure of nitrogen is advantageous in reducing nitrogen uptake in the body's tissues, thereby extending the practicable underwater dive time by reducing the decompression requirement, or reducing the risk of decompression sickness.
Pneumatics use of gas or pressurized air in mechanical systems.
An air compressor is a machine that takes ambient air from the surroundings and discharges it at a higher pressure. It is an application of a gas compressor and a pneumatic device that converts mechanical power into potential energy stored in compressed air, which has many uses. A common application is to compress air into a storage tank, for immediate or later use. When the delivery pressure reaches its set upper limit, the compressor is shut off, or the excess air is released through an overpressure valve. The compressed air is stored in the tank until it is needed. The pressure energy provided by the compressed air can be used for a variety of applications such as pneumatic tools as it is released. When tank pressure reaches its lower limit, the air compressor turns on again and re-pressurizes the tank. A compressor is different from a pump because it works on a gas, while pumps work on a liquid.
A self-contained breathing apparatus (SCBA) is a respirator worn to provide an autonomous supply of breathable gas in an atmosphere that is immediately dangerous to life or health from a gas cylinder. They are typically used in firefighting and industry. The term self-contained means that the SCBA is not dependent on a remote supply of breathing gas. They are sometimes called industrial breathing sets. Some types are also referred to as a compressed air breathing apparatus (CABA) or simply breathing apparatus (BA). Unofficial names include air pack, air tank, oxygen cylinder or simply pack, terms used mostly in firefighting. If designed for use under water, it is also known as a scuba set.
A breathing gas is a mixture of gaseous chemical elements and compounds used for respiration. Air is the most common and only natural breathing gas, but other mixtures of gases, or pure oxygen, are also used in breathing equipment and enclosed habitats. Oxygen is the essential component for any breathing gas. Breathing gases for hyperbaric use have been developed to improve on the performance of ordinary air by reducing the risk of decompression sickness, reducing the duration of decompression, reducing nitrogen narcosis or allowing safer deep diving.
A diving cylinder or diving gas cylinder is a gas cylinder used to store and transport high pressure gas used in diving operations. This may be breathing gas used with a scuba set, in which case the cylinder may also be referred to as a scuba cylinder, scuba tank or diving tank. When used for an emergency gas supply for surface supplied diving or scuba, it may be referred to as a bailout cylinder or bailout bottle. It may also be used for surface-supplied diving or as decompression gas. A diving cylinder may also be used to supply inflation gas for a dry suit or buoyancy compensator. Cylinders provide gas to the diver through the demand valve of a diving regulator or the breathing loop of a diving rebreather.
A diving air compressor is a breathing air compressor that can provide breathing air directly to a surface-supplied diver, or fill diving cylinders with high-pressure air pure enough to be used as a hyperbaric breathing gas. A low pressure diving air compressor usually has a delivery pressure of up to 30 bar, which is regulated to suit the depth of the dive. A high pressure diving compressor has a delivery pressure which is usually over 150 bar, and is commonly between 200 and 300 bar. The pressure is limited by an overpressure valve which may be adjustable.
An anaesthetic machine or anesthesia machine is a medical device used to generate and mix a fresh gas flow of medical gases and inhalational anaesthetic agents for the purpose of inducing and maintaining anaesthesia.
Bottled gas is a term used for substances which are gaseous at standard temperature and pressure (STP) and have been compressed and stored in carbon steel, stainless steel, aluminum, or composite containers known as gas cylinders.
Gas blending for scuba diving is the filling of diving cylinders with non-air breathing gases such as nitrox, trimix and heliox. Use of these gases is generally intended to improve overall safety of the planned dive, by reducing the risk of decompression sickness and/or nitrogen narcosis, and may improve ease of breathing.
An oxygen concentrator is a device that concentrates the oxygen from a gas supply by selectively removing nitrogen to supply an oxygen-enriched product gas stream. They are used industrially, to provide supplemental oxygen at high altitudes, and as medical devices for oxygen therapy.
Pressure swing adsorption (PSA) is a technique used to separate some gas species from a mixture of gases under pressure according to the species' molecular characteristics and affinity for an adsorbent material. It operates at near-ambient temperature and significantly differs from the cryogenic distillation commonly used to separate gases. Selective adsorbent materials are used as trapping material, preferentially adsorbing the target gas species at high pressure. The process then swings to low pressure to desorb the adsorbed gas.
Industrial gases are the gaseous materials that are manufactured for use in industry. The principal gases provided are nitrogen, oxygen, carbon dioxide, argon, hydrogen, helium and acetylene, although many other gases and mixtures are also available in gas cylinders. The industry producing these gases is also known as industrial gas, which is seen as also encompassing the supply of equipment and technology to produce and use the gases. Their production is a part of the wider chemical Industry.
The Pin Index Safety System (PISS) is a means of connecting high pressure cylinders containing medical gases to a regulator or other utilization equipment. It uses geometric features on the valve and yoke to prevent mistaken use of the wrong gas. This system is widely used worldwide for anesthesia machines, portable oxygen administration sets, and inflation gases used in surgery.
A cascade filling system is a high-pressure gas cylinder storage system that is used for the refilling of smaller compressed gas cylinders. In some applications, each of the large cylinders is filled by a compressor, otherwise they may be filled remotely and replaced when the pressure is too low for effective transfer. The cascade system allows small cylinders to be filled without a compressor. In addition, a cascade system is useful as a reservoir to allow a low-capacity compressor to meet the demand of filling several small cylinders in close succession, with longer intermediate periods during which the storage cylinders can be recharged.
An air separation plant separates atmospheric air into its primary components, typically nitrogen and oxygen, and sometimes also argon and other rare inert gases.
A booster pump is a machine which increases the pressure of a fluid. It may be used with liquids or gases, and the construction details vary depending on the fluid. A gas booster is similar to a gas compressor, but generally a simpler mechanism which often has only a single stage of compression, and is used to increase pressure of a gas already above ambient pressure. Two-stage boosters are also made. Boosters may be used for increasing gas pressure, transferring high pressure gas, charging gas cylinders and scavenging.
Scuba gas management is the aspect of scuba diving which includes the gas planning, blending, filling, analysing, marking, storage, and transportation of gas cylinders for a dive, the monitoring and switching of breathing gases during a dive, efficient and correct use of the gas, and the provision of emergency gas to another member of the dive team. The primary aim is to ensure that everyone has enough to breathe of a gas suitable for the current depth at all times, and is aware of the gas mixture in use and its effect on decompression obligations, nitrogen narcosis, and oxygen toxicity risk. Some of these functions may be delegated to others, such as the filling of cylinders, or transportation to the dive site, but others are the direct responsibility of the diver using the gas.
Gas blending is the process of mixing gases for a specific purpose where the composition of the resulting mixture is specified and controlled. A wide range of applications include scientific and industrial processes, food production and storage and breathing gases.
