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Wednesday, September 18, 2013

Cryogenic Flasks

Cryogenic flasks are containers that are specially crafted for holding cryogens, such as liquid nitrogen and liquid helium. Cryogens can potentially be very hazardous and these specialized containers are designed to hold them safely. These containers can come a few different styles, from storage to everyday lab use.

Cryogenic storage dewars are constructed of two or more layers and contain a strong vacuum that is maintained to provide excellent thermal insulation and prevents the cryogenic liquids from evaporating. If these containers are completely sealed, the gas will build up on the inside of the flask and can cause high-velocity explosions which can cause injury and property damage. These containers are constructed with safety valves that allow the evaporating gas to escape through that valve that prevents explosions. More advanced containers are made that are able to trap the gas above the liquid cryogens and are able to hold the gas at higher pressures than standard containers. Some containers may simply be tipped to allow the liquid inside out, but more advanced containers use the pressure at the top to force the liquid out through a pipe in the neck.

Although cryogenic flasks contain the liquids safely, there is no way to prevent the liquids inside from boiling away entirely. These types of containers are not to be used as a permanent home for cryogenic liquids. The vapor from these containers causes a great buildup of gas in the location in which they are stored, which can displace the oxygen in the area. It is highly recommended that these containers be kept in well ventilated areas. Cryogenic dewars are susceptible to ice buildup, which can cause blocked safety valves, which may lead to an excessive buildup of pressure. This is caused by the container being left open and air being able to make contact with the liquid, at which point ice will form and cause this to take place.

Everyday lab use typically requires the use of smaller cryogenic flasks that allow for the ability to transfer and measure the liquid cryogens. These advanced holding containers usually have a specific holding time, which is the maximum amount of time that the liquid cryogens should be left inside of them. They are made of aluminum, polyethylene, glass, and other advanced containment materials to withstand the extreme temperatures of the contents. The flasks often come with weighted bases and are available in many different sizes and depths depending on the various lab uses. This type of flask usually comes with a tip that allows for no-mess pouring.

Shallow, wide mouth flasks are available for lab use and allow a person to contain cryogenic liquids and allow for the option to manipulate them at the same time. Allowing for the insertion of lab tools, this type of flask is convenient for agitation of cryogenic liquids, quick freezing and recovery of organ specimens, and the tempering of stirring rods and pestles.

All of these types of containers are available from laboratory supply dealers. Locate your nearest one, or save time and shop online. Always use proper protection when handling hazardous materials.  

by: getMedOnline

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