Cryogenics, a branch of low-temperature physics concerned with the effects of very low temperatures on the phenomenas and materials, was first investigatred by Micahel Faraday, who demonstrated that gases could be liquefied leading to the production of low temperatures around 173 K.
The most prominent contributors to cryogenic technology include five distinguished physicist and chemists, namely, Andrews, C. de la Tour, Faraday, Joule and Thomson. Between 1820 and 1870, the latter two demonstrated the dependence of the gas's energy on the operating pressure and temperature. Andrew performed a series of experiments in 1869 with CO2 and discovered a critical temperature above which the liquid state cannot exists regardless of pressure. Later researcher studied the properties of permanent gases. A french scientist, Cailletet, liquified oxygen for the first time in 1877; Polish physicists Wroblewski and Olszewski liquified oxygen and air in large quantities during the 1880s; and English physicist, Dewar, first liquified hydrogen gas in 1898; and a Dutch physicist, Kamerlingh-Onnes, first liquified helium gas in 1908.
Most cryogenic liquids are odorless, colorless, and tasteless when vaporized. When cryogenic liquids are exposed to the atmosphere, the cold boil-off gases condense the moisture in the air, creating a highly visible fog.
• Cryogenic liquids MUST be used in a well ventilated area. All crogenic liquids produce large volumes of gas when they vaporize. For example, one liter of liquid nitrogen dispalces 694 liters of air when it vaporizes.
• When used in sealed containers, this vaporization can produce enourmous pressures.
• Always wear proper gloves.
• Always use proper containers designed for the transport and use of cryogenic liquids.
• Examine containers and pressure relief valves for signs of defect. Never use a container which has defects.
• Always handle these liquids carefully to avoid skin burns and frostbite. Exposure that may be too brief to affect the skin of the face or hands may damage delicate tissues, such as the eyes.
• Boiling and splashing always occur when charging or filling a warm container with cryogenic liquid or when inserting objects into these liquids. Perform these tasks slowly to minimize boiling and splashing. Use tongs to withdraw objects immersed in a cryogenic liquid.
• When transferring into a secondary container, do not fill the secondary container to more than 80% of capacity
• Use wooden or rubber tongs to remove small items from cryogenic liquid baths. Cryogenic gloves are for indirect or splash protection only, they are not designed to protect against immersion into cryogenic liquids.