Helium is a really special specialty gas: in addition to what is probably the best-known use of helium as a lifting gas for balloons and airships, this rare gas has a whole range of other uses thanks to its special properties. For example, it is used in many processes in welding and laser technology because of its high thermal conductivity. “However, its high diffusibility also makes it an ideal carrier gas in gas chromatography and the most widely used test gas for leak detection,” explains Dr. Michael Hanisch, Technology Manager Specialty Gases, Messer Group.

Extremely cold
In a liquid state, helium has the lowest boiling point of all gases at 4.2 Kelvin or minus 269 degrees Celsius. This makes liquid helium the coldest liquid on Earth. It is used as a refrigerant wherever extremely low temperatures (below minus 200 degrees Celsius) are required. An example of this would be applications connected with the generation of very strong magnetic fields using superconductive magnets. From a technical viewpoint, the most important applications are magnetic resonance imaging (MRI) in medicine and nuclear magnetic resonance spectroscopy (NMR) as well as several applications in pure research. Helium is extracted from helium-rich natural gas wells, which are found in only a few places worldwide. For the European market, Messer draws on a very reliable Russian source. To import the gas, Messer operates a fleet of special super vacuum-insulated tank containers with a capacity of 40,000 liters each. Continued on page 10 These are used to transport the helium to our European filling plants in MMitry-Mory (France), Lenzburg (Switzerland) and Gumpoldskirchen (Austria). At these plants, Messer transfers the helium into smaller dewars, which are designed for supplying customers and are also super vacuum-insulated. Gaseous helium is also filled at these plants. Our Chinese plant in Wujiang is supplied from a source in the USA.

High-purity gases and gas mixtures
Many technologies require pure gases or gas mixtures of defined composition and quality in order to operate safely and efficiently. The inert gas filling in incandescent lamps prevents the filament from burning up. Nowadays, krypton mixtures are also frequently used for this. The lower thermal conductivity allows higher filament temperatures and therefore greater light output. If a particularly high luminance is required, for example in car headlights, then xenon-filled gas discharge lamps are used. The rare gas filling in insulated glass units ensures improved thermal and acoustic insulation. Very high demands are also placed on gases that are used in the operation of sensitive analytical equipment in environmental analysis, safety engineering or quality assurance. In addition to the carrier and process gases for the instruments and detectors used in gas analysis, gas mixtures with a specific and precise composition are also used in order to calibrate the devices. “There are only a few standard products in this area, so Messer produces calibration gases to individual customer specifications,” says Jerry Girardi, Sales Manager Specialty Gases for Messer in Switzerland. In line with the many different applications, there are very different requirements in terms of the quality and form of delivery of the gases. Messer offers a comprehensive range of standard products. The purities range from “technical” through to “6.0 quality” with a purity level of 99.9999 percent. Messer supplies the gases as and when required. Our products range from one-liter pressure cans to cylinders and bundles through to trailer and liquid supplies.

Knowing how it's done...
The production of specialty gases consists of various stages, from the pretreatment of cylinders to filling technology through to quality assurance analysis. A sound understanding of each individual area as well as a firm grasp of the entire process chain are essential. “Through our many years of experience in the local specialty gas plants, Messer is able to supply almost any technically feasible gas mixture with the desired composition and the required degree of precision,” says Dr. Bruno Reimann, Coordinator Specialty Gases Production/Analysis Europe. We can also offer the option of supplying a wide range of calibration gases with a certificate of accreditation. However, specialty gases also require special know-how in terms of their application. In order to ensure that the desired quality is maintained from the storage vessel to the application, special precautions are necessary at the installations. Not all technically approved fittings can also be used for specialty gases as well. Together with our sister company, Messer Cutting & Welding, a leading manufacturer of fittings and gas supply systems, Messer offers suitable solutions for every application – from planning through to complete installation.