Liquid nitrogen is a fascinating and useful tool that can be used in many different industries including welding, farming, medical and food service. Many schools and families use it for science experiments or ice cream as well. However, there are some things that you need understand about this versatile refrigerant in order to handle it wisely.
One of the most important things that you need to consider when purchasing liquid nitrogen is how you are going to store it. There are many suggestions from people on the internet that say you can use a thermos or some other small storage container when you only need a small amount of liquid nitrogen. However, this is an extremely dangerous suggestion.
Because liquid nitrogen boils at a much lower temperature than room temperature, it turns back into a gas as it warms, and can create extreme amounts of pressure. Specially made liquid nitrogen tanks, called dewars, are vented in order to allow the nitrogen gas to escape. They do not seal shut and are not pressurized because if they were, the nitrogen inside could explode.
Another thing that you need to consider when purchasing liquid nitrogen is how often or quickly you will be using it. Because of the way that it is vented, your supply of liquid nitrogen will deplete over time. If you are using it regularly, having a large storage dewar can save you the hassle of having to get a refill frequently, but if you are only using liquid nitrogen occasionally, it may be better have a smaller container, and simply refill it as needed.
Due to the required ventilation, transporting liquid nitrogen can pose its own set of unique challenges. Liquid nitrogen expands to almost 700 times its original volume when it turns back into a gas. Because of this, transporting liquid nitrogen inside the cab of a closed vehicle is very unsafe. A better idea would be to have the liquid nitrogen delivered. If you are picking up the liquid nitrogen yourself, make sure that you are using a vehicle with an open bed, such as a truck, in order to transport it safely.
By itself, liquid nitrogen is fairly inexpensive. The dewars can be rather pricey if you are buying them outright, but that price can be offset over time if you plan to use a lot of liquid nitrogen. However, if you are only planning on using a small amount of liquid nitrogen, or you don't need it very often, it may be worth finding out if the company you are purchasing your nitrogen from offers equipment rentals. If so, you may be able to rent a dewar from them for a reasonable price.
By considering the storage, time, transport, and price of your liquid nitrogen, you can make sure that your purchase of liquid nitrogen is both safe and economical. Talk to experts like Cryotek Inc for more information.