Nitrogen Fill

1. Check the sensor for the helium.  Turn the sensor on by moving the switch to the right.  Wait a few minutes to get an accurate reading.  In the black note book that is placed by the sensor box, write down the date on a new line and the percentage of the helium that is in the tank and the flow rate.  Turn off the sensor and place the book back where it was.
2. Connecting the nitrogen tank to the NMR.  Unplug the rubber hoses at the top of the NMR and place the rubber stoppers in the middle of the top. Check to see if the hoses are touching the tank, if they are then move them to where they are not touching the NMR. Take the hose off of the hooks on the wall.  The hose is the one with the weave on it.  Connect the end with out a turn to the nitrogen tank at the liquid nozzle.  Take the other side with the turn and connect it with the NMR.  The opening to place the nozzle is on the other side of the two rubber hoses and it sticks up with a cap on it, on top of the NMR.  Make sure that the hose nozzle is completely down on the opening and tighten the end.  The hose should not be touching the tank.  Make sure both ends are tight so the nitrogen does not leak.  There are wrenches to help tighten the ends. 
3. Filling the nitrogen tank.  Turn the knob above the nozzle to start the nitrogen flow but don’t turn it on all the way, just a little.  Wait until the nitrogen flow is steady.  To tell if the nitrogen flow is steady, watch the vapor that comes out of the rubber tubes, it will pulse if the flow is unsteady. Listen for the liquid nitrogen flowing through the transfer line (a gurgling noise).  Once the flow is steady, you may open the nozzle a little more to make the fill faster.  When liquid nitrogen starts coming out of the rubber hoses then the nitrogen fill is done.  Take a work glove and turn the knob to stop the flow of nitrogen.  Sometimes there is not enough nitrogen in the nitrogen tank to do a complete fill, if that happens the nitrogen tank will start a steady hissing noise that come from the hose.  Turn off the flow with the work glove.
4. Disconnecting the nitrogen tank from the NMR.  Wait a half an hour so the hose can warm up to room temperature.  Unscrew the ends of the hose and place the hose on the hooks on the wall.  Place the cap back on the opening on the NMR and put the rubber stoppers back into the rubber hoses.