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Maintenance for Helios

Wednesday, March 6, 2013
Liquid Nitrogen Auto Fill System
Equipment/Beam Line: 

We recently replaced the original liquid nitrogen level sensor with a new one base on capacitance measurement from America Magnetic Inc. The new sensor, solenoid valve and Model 186 level controller are used for the monitoring and Auto-Filling of liquid nitrogen.

The setting used as of 2013

Interval                                25 min                   Maximum fill time

Length                                5.5 inch                 DO NOT CHANGE

LO                                       20 %                     Relay contacts are closed à Warning

B                                          35 %                     Fill

A                                          85 %                     Stop filling

HI                                          100%


For the liquid nitrogen trip (warning) to work on the Remote Annunciator Panel of Helios with the LO signal from the Model 186, we had to reverse the logic in the Remote Annunciator box.

Relay RT2, move 2 wires labeled 9. From the top left corner to the lower right corner of terminal block #2.

Bassam Hitti