Thursday 23 January 2014

Facts Concerning Cryogenic Gases That Are Worth Understanding

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 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 used, stored, and transported in highly insulated containers. The containers are constructed in a manner as to endure quick changes in temperature and great differences in temperature. Examples of containers utilized include gas cylinders, laboratory liquid dewar flasks, and liquid dewar flasks. Gas cylinders comprise valves for filling up and dispensing the gas and pressure-regulating valves with frangible disks to act as backup protection.

There are several health hazards associated with these substances and precaution must be taken when handling them. The health hazards are classified into three groups, that is toxicity, asphyxiation, and extreme cold. The cold gas and its associated vapor can cause effects on the skin similar to thermal burns. Brief exposure that cannot affect skin can affect delicate tissues like eyes. Other effects include frostbite, pain, sticking on cold surface, and lung damage.

Many of these gases are usually heavier than air in the atmosphere. They therefore displace atmospheric air and settle on floors creating oxygen shortage. Oxygen deficiency may cause asphyxiation and eventually death. Therefore it is not advisable to handle these materials in enclosed spaces with poor ventilation. Materials such as carbon (II) Oxide are greatly toxic and may cause death in seconds if they leak out into the environment.

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, 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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