The Ebb and Flow of Liquid Nitrogen through the Years



Portable Dewar from the "old" days



When the tissue bank was established, our liquid nitrogen freezers were attached to portable dewar tanks which had to be exchanged periodically.  In order to get the tanks into our building, they had to be wheeled up a rather long ramp.  This process was not easy and required more than one person to heave the tanks to their destination.  I imagine the architect did not take into consideration how much exertion would be required to move a large tank up a long hill… As we grew and moved into a new facility, we switched to two 1500 gallon stationary bulk tanks for our supply source.  We monitored the levels in the tanks daily and telephoned in our order every 2 weeks.



Filling bulk tank with liquid nitrogen



Several years later, we transitioned to one 3000 gallon tank. The  video below shows the venting of liquid nitrogen out of the tank into the atmosphere.  This had to be done before the unit was taken out of service.  If I had planned ahead, we would have had enough Dippin Dots for the entire department. The larger 3000 gallon tank offered several improvements.  Along with a cost savings, there are less frequent fill ups and a high-tech monitoring system.  The new tank is equipped with wireless telemetry allowing remote monitoring of the nitrogen level.  Deliveries of nitrogen are automatically scheduled without a call from us!