17 Nov

Dry Ice

Where to get dry ice?  Laboratories which may need an intermittent supply of dry ice can produce it in the lab with dry ice makers; these use a 50lb liquid CO2 dip tube(syphon) cylinder. The dry ice machines use the expansion of the CO2 gas from the compressed gas cylinder to cool the Carbon Dioxide into dry ice by adiabatic cooling process. When a gas is under pressure and then released to the atmosphere heat is removed from the surroundings, this is how refrigerators and air conditioners work. In general 80% of the gas is used to cool the CO2 and 20% becomes dry ice in a dry ice maker. Bel-Art Scienceware manufactures the Frigimat dry ice maker which makes dry ice blocks and dry ice flakes SCA Thermosafe also produces a dry ice machine which make dry ice blocks.

Carbon Dioxide is one of many substances which pass from a solid to a gas without going through a liquid state; this is known as sublimation. Solid Carbon Dioxide -Dry Ice – Card Ice, will sublimate at room temperature and atmospheric pressure. Naphthalene (mothballs) also sublimates at room temperature. Iodine crystals will sublimate at atmospheric pressure if heated. Snow and ice sublimate on a sunny day in winter.

Dry ice is used commonly as a refrigerant in transporting food and biological materials. Dry Ice is used in the laboratory along with organic solvents to quickly chill samples; it is also used in the condensers of rotary evaporators. Where to buy dry ice?  Dry ice can be supplied regularly from local welding or refrigeration supply companies.

 

Robin Prymula