Facts About Cryogenic Gases That Need To Be Understood

By Grace Rivas

Cryogenic gases refer to gases that are maintained in either gaseous or liquid form at very low temperatures. The gasses have a boiling point of low than -150 degrees Centigrade. At normal pressure and temperature, these substances exist in gaseous form. They normally have two main characteristics. The first one is, when liquefied, small amounts of liquid can expand into very large amounts of gas. The second characteristic is that they are extremely cold.

Because of their low temperatures, they condense the atmospheric air to create fog that can be seen by the eyes. When stored in tanks that are poorly insulated, they condense the surrounding air to form a mixture of air and liquid. According to the WHMIS criteria, they are classified as compressed gasses.

Every cryogenic material has its own characteristics, although many of them can be classified in one of these groups. The groups are oxygen and flammable or inert gasses. Inert gas does not undergo a lot of chemical reactions with other materials. Materials classified under the inert group include neon, krypton, nitrogen, and Oregon. Flammable gas can undergo combustion in atmospheric air. Main examples are methane, hydrogen, and liquefied natural gas among others. Most materials considered non-combustible burn when combined with liquid atmospheric oxygen. This makes it vital to handle oxygen with safety measures that are not similar to those of the other cryogenics.

These substances are stored, transported, and used in containers that are highly insulated. The containers are designed in a way that they can withstand fast changes in temperature and they can also endure great temperature differences. Examples of containers that are used include laboratory liquid dewar flasks, liquid dewar flasks, and gas cylinders. Gas cylinders have valves for dispensing and filling the gas and pressure-control valves with frangible disks for backup protection.

There are many health hazards connected to these substances and care must be taken in handling them. The health dangers are classified into 3 groups, that is, asphyxiation, extreme cold, and toxicity. The cold gas and the associated vapor may cause effects on skins similar in appearance and effect as thermal burns. Brief exposures that cannot affect skins can affect delicate tissues such as eyes. Other effects are frostbite, pain, lung damage, and sticking on cold surfaces.

Many of cryogenic gases are heavier than air. They therefore displace air and settle down on floors creating a vacuum of oxygen. Oxygen deficiency might cause asphyxiation and death. Hence it is not recommendable to handle these materials inside enclosed poorly ventilated spaces. Materials like carbon (II) Oxide are very toxic and might cause death immediately if they seep out into the surroundings.

These substances have several uses in various applications. First, the liquid forms are used as fuels in powering rockets and other high-speed planes. Other applications include food and blood conservation, electrical power transmission, magnetic resonance imaging, nuclear magnetic resonance spectroscopy, and forward looking infrared. Certain rare blood types need to be stored under extremely low temperatures to remain viable. They are also used in making detectors.

Of all Cryogenic gases, liquid nitrogen is the most widely used. It is legal for purchase and can be purchased from anywhere around the world. Dewar flasks are seemingly the best storage units used.

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