Filling up tank

You fill up the cryo tank by transferring liquid nitrogen from a commercial tank. Do the following.

1. Hook up the connector shown in the figure with the end labeled "use" on the commercial liquid nitrogen tank. Connect the open end that has the female end of the so-called "easy connect" connector to the dark-gray hose that has the male end of the "easy connect" connector.

2. Connect the black rubber tube between the filling valve of the cryo tank and the "liquid" end of the commercial tank.

3. Turn the switch on the control unit to FILL position, open the valve of the "use" end on the commercial tank and adjust the flow meter to give you a reasonably strong flow (set up 30 or abve). At this time, you should feel gas coming out of the cooling tube nozzle.

4. Lift up the two handles on your cryo tank (one for filling and the other for releasing pressure) and then gradually open the valve of the "liquid" end on the commercial tank. At this time, you'll hear very loud noise because the high pressured liquid nitrogen is rushing to the cryo tank from the commercial tank. Don't worry, it's normal (actually it's abnormal if you do not hear the noise). Also, you'll see gas puffing out the pressure release tube of the cryo tank.

5. About ten to twenty minutes later, check the liquid nitrogen level in the cryo tank by sticking a long and thin black stick (available in the lab) into the tank through the pressure release tube. Let it drop all the way to the bottom, sit there for a couple of seconds and then quickly take it out. In a couple of seconds, you'll see frost on the part of the stick that was soaked in the liquid nitorgen. This tells you how much liquid nitrogen you've filled in the cryo tank. Note you should fill between the minimum and maximum markers on the stick.

6. Once you've filled up to the level you want, close the "liquid" valve on the commercial tank, push down the handles on the sryo tank, and watch the tank pressure indicator on the control station. If it's between the two red markers, you can start run the system; otherwise open the pressure release valve and wait until the pressure comes to the specified range. You may have to do this several times until the pressure stablized.