Helium Cylinder
Helium is an inert monatomic gas without color, taste or smell (the chemical formula is He). Helium is the second most abundant chemical substance in the universe after hydrogen (about 23 % by mass) and the second lightest one, also after hydrogen. Despite its prevalence in the universe, helium is scarce on Earth: 1 m3 of air contains only 5.24 cm3 of helium, and each kilogram of Earth's material contains 0.003 mg of helium. Helium is liquefied at about -268 °C, its boiling point is -268.9 °C, and its melting point is -272.2 °C. Helium is the only element that does not solidify, remaining liquid at atmospheric pressure and any low temperature. Transition to solid state is possible only at pressures over 25 atm. There are three main sources of helium: from helium-containing natural gases, from minerals, and from the air. But on an industrial scale, helium is only extracted from helium-containing natural gases (currently, mainly fields containing more than 0.1% helium are being exploited). Helium is separated from the other gases by deep cooling, taking advantage of the fact that it is more difficult to liquefy than all the other gases. The process is usually carried out in two stages: extraction of the so-called raw helium (a concentrate containing 70-90% He) and purification to produce technically pure helium.
APPLICATION:
• to create a protective atmosphere during melting, cutting and welding of active metals (helium is less conductive than the other inert gas - argon, and therefore the electric arc in a helium atmosphere gives higher temperatures, which significantly increases the speed of arc welding); • as a refrigerant for obtaining ultra-low temperatures; • for filling aeronautical crafts (airships and balloons); • for filling balloons and shells of meteorological probes; • as a coolant in some types of nuclear reactors; • for filling gas discharge tubes; • as a carrier in gas chromatography; • for leak detection in pipelines and boilers; • as a component of the working fluid in helium-neon lasers; • as a component of artificial air supplied to divers for breathing (replacement of nitrogen with helium prevents decompression disease). Requirements for transportation, storage and use of cylinders for gaseous helium are established by the Federal standards and regulations in the field of industrial safety "Regulations of industrial safety for hazardous facilities using equipment operating under excessive pressure", GOST 20461-75 "Gaseous helium. Method for determination of impurities volume fraction by emission spectral analysis (with Amendments N 1, 2, 3, 4)", safety standards, as well as other laws and regulations and international agreements in force on the territory of the Russian Federation.Cylinders are not hazardous cargo until they are taken into use, but in any case they should be transported in conditions that exclude mechanical damage. Cylinders filled with gaseous helium shall be transported by all modes of transport in accordance with cargo carriage regulations applicable to this mode of transport, as well as safety rules for transportation of dangerous goods by rail. Cylinders may be transported in special containers, as well as without containers in an upright position, always with spacers between them and secured against possible falling. The cylinders must be transported with caps screwed on.
Cylinders designed for storage and transportation of gaseous helium must not be used for storage and transportation of other gases, and it is prohibited to perform any operations that may contaminate their internal surface and degrade the physical and chemical properties of the gas. It is forbidden to make any modifications to the cylinder bodies using welding or mechanical tools, which can lead to damage to the integrity or appearance of defects that degrade the technical characteristics of the cylinders. When using cylinders for gaseous helium it is not allowed to install them in the places of people passage, movement of goods and passage of vehicles. Cylinders must be located at least 1 m away from radiators and other heating devices and at least 5 m from heat sources with open flame. The nominal pressure of helium in a full cylinder at 20 °C should be 14.7 MPa (150 kgf/cm2) or 19.6 MPa (200 kgf/cm2). The gas in the cylinders must not be completely consumed when in use. The residual gas pressure in the cylinder must be at least 0.05 MPa (0.5 kgf/cm2).
Cylinders with gaseous helium can be stored both in special rooms and in the open air, in the latter case they must be protected from atmospheric precipitation and sunlight. Cylinders filled with gaseous helium may be stored in open areas together with other gases, provided that the storage areas are separated from each other by non-combustible barriers with a height of 1.5 m, joint storage with cylinders filled with combustible gases is also allowed, provided that the storage areas are separated from each other by non-combustible protective walls not less than 2.5 m high. Storage of cylinders should be carried out with the caps screwed on.