Facts Concerning Cryogenic Gases That Should Be Understood

By Grace Rivas

Cryogenic gases are gases that are kept in either liquid or gaseous form at extremely low temperatures. They have boiling points of low than -150 degrees Celsius. At normal temperature and pressure, these substances exist in their gaseous form. They usually have 2 main characteristics. The first characteristic is, when liquefied, small quantities of liquid can melt into very large quantities of gas. The 2nd property is that they are very cold.

Because of their extremely low temperatures, they condense atmospheric air to form fog that is visible to the eye. When kept in containers that are insulated poorly, they condense surrounding air to create a mixture of liquid and air. According to WHMIS criteria, they are categorized as compressed gasses.

Every cryogenic substance has its own properties, although most of them can be placed in one of the following classes. The classes are, oxygen, inert and flammable gasses. Any inert gas does not have much chemical reaction with other substances. They include neon, Oregon, krypton, and nitrogen. Flammable gas can burn in atmospheric air. Common examples are liquefied natural gas, methane, and hydrogen among others. Most substances considered non-combustible burn when mixed with liquid oxygen. This makes it important to handle oxygen with precautions that are different from those of 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 many uses in various domestic, governmental and industrial applications. First, the liquefied forms are utilized as fuels in fuelling rockets and other high-velocity planes. Other applications consist of food and blood preservation, magnetic resonance imaging, electrical power transmission, forward looking infrared, and nuclear magnetic resonance spectroscopy. Certain rare blood groups need to be kept under extremely low temperature to remain useful. They are also utilized in making detectors.

Of all Cryogenic gases, liquefied nitrogen gas is the most commonly utilized. It is legal for acquisition and can be bought from any place around the globe. Dewar flasks are apparently the best storage containers used.

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