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Most weld purging is carried out on joints made by the TIG or GTAW arc welding process. [6] When the laser welding process is chosen, joints or welds being made on reactive materials will need to be carried out and in the case of electron beam welding, this is carried out in a vacuum, in which case purging takes place by complete evacuation of all gas.
The purge gas is inert, i.e. by definition [1] non-combustible, or more precisely, non-reactive. The most common purge gases commercially available in large quantities are nitrogen and carbon dioxide. Other inert gases, e.g. argon or helium may be used. Nitrogen and carbon dioxide are unsuitable purge gases in some applications, as these gases ...
A cryogenic gas plant is an industrial facility that creates molecular oxygen, molecular nitrogen, argon, krypton, helium, and xenon at relatively high purity. [1] As air is made up of nitrogen, the most common gas in the atmosphere, at 78%, with oxygen at 19%, and argon at 1%, with trace gasses making up the rest, cryogenic gas plants separate air inside a distillation column at cryogenic ...
Nitrogen, argon, helium and other inert gases are commonly used. To maximize this process called sparging , the solution is stirred vigorously and bubbled for a long time. Because helium is not very soluble in most liquids, it is particularly useful to reduce the risk of bubbles in high-performance liquid chromatography (HPLC) systems.
In other cases, a purge-cycle technique is often employed, where the closed, reaction vessel connected to the line is filled with inert gas, evacuated with the vacuum and then refilled. This process is repeated 3 or more times to make sure air is rigorously removed.
Fig. 1. The surface of a MEMS device is cleaned with bright, blue oxygen plasma in a plasma etcher to rid it of carbon contaminants. (100mTorr, 50W RF) Plasma cleaning is the removal of impurities and contaminants from surfaces through the use of an energetic plasma or dielectric barrier discharge (DBD) plasma created from gaseous species.
A blowout preventer (BOP) (pronounced B-O-P) [1] is a specialized valve or similar mechanical device, used to seal, control and monitor oil and gas wells to prevent blowouts, the uncontrolled release of crude oil or natural gas from a well. They are usually installed in stacks of other valves.
The argon bubbles rise to the surface, bringing with them some of the dissolved hydrogen. The degassing step reduces the occurrence of hydrogen gas porosity . In the steel making process, this method is used very commonly for duplex steel and some high reactivity metals.